Dozer blade driving mechanism

Abstract

To operate a dozer blade using an electric motor as a power source.SOLUTION: A shovel car 500 includes: an arm 70 which is rotatably connected to a housing main part 410, and can mount a dozer blade 300 on a side opposite to a connection part with the housing main part 410; a power generator 30 which includes a motor 31 as a driving source, and generates a torque with a center axis 31A parallel with a rotation center axis of the arm 70 as a center; and a link mechanism 40 for transmitting the torque generated by the power generator 30, as rotation operation of the dozer blade 300 with the rotation center axis as a center. The center axis 31A of the motor 31 is located on a side closer to the dozer blade 300 than the center of an arm line segment LX connecting a connection part with the housing main part 410 in the arm 70, and a connection part with the dozer blade 300 in the link mechanism 40, when being viewed in a direction parallel with the center axis 31A of the motor 31.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a dozer blade drive mechanism. [Background technology]

[0002] The hydraulic excavator disclosed in Patent Document 1 includes a dozer blade, a dozer cylinder, and a dozer arm. The dozer arm connects the dozer blade to the frame of the hydraulic excavator. The dozer arm rotates around the connection point with the frame. The dozer cylinder connects the dozer blade to the frame at a position above the dozer arm. Hydraulic oil is supplied to and discharged from the dozer cylinder. The dozer cylinder expands and contracts in response to the supply and discharge of hydraulic oil. The dozer blade rises and falls in response to the expansion and contraction of the dozer cylinder. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-88796 Summary of the Invention [Problem to be solved by the invention]

[0004] Patent Document 1 only discloses hydraulic pressure as a power source for raising and lowering the dozer blade, and does not consider raising and lowering the dozer blade using a power source other than hydraulic pressure. [Means for solving the problem]

[0005] A dozer blade drive mechanism for solving the above problem comprises a connecting member that is rotatably connected to the body of a construction machine and to which a dozer blade can be attached on the side opposite to the point of connection with the body, a power generating device that includes an electric motor as a drive source and generates torque about a central axis parallel to the central axis of rotation of the connecting member, and a link mechanism that transmits the torque generated by the power generating device as a rotational movement of the dozer blade about the central axis of rotation, and when viewed in a direction parallel to the central axis, the central axis is located closer to the dozer blade than the center of the line segment connecting the point of connection of the connecting member with the body and the point of connection of the link mechanism with the dozer blade.

[0006] According to the above configuration, the torque of the power generating device can be transmitted to the dozer blade via the link mechanism. The dozer blade then rotates in response to the power of the electric motor. In other words, according to the above configuration, the dozer blade can be operated using the electric motor as a power source.

[0007] In the dozer blade drive mechanism, the link mechanism has a first link that receives torque from the power generating device and rotates about the central axis, and a second link that is rotatably connected to both the first link and the dozer blade, and when viewed in a direction parallel to the central axis, a line segment connecting the central axis and a connection point of the first link with the second link is defined as a first line segment, and a line segment connecting the connection point of the second link with the first link and a connection point of the second link with the dozer blade is defined as a second line segment, the length of the first line segment may be 50% or more and 200% or less of the length of the second line segment.

[0008] In the dozer blade drive mechanism, the link mechanism has a first link that receives torque from the power generating device and rotates around the central axis, and a second link that is rotatably connected to both the first link and the dozer blade, and when it is assumed that the dozer blade is in contact with the ground on which the construction machine is traveling, the connection point of the second link with the dozer blade may be located lower than the connection point of the second link with the first link.

[0009] In the dozer blade drive mechanism, when viewed in a direction parallel to the central axis, a line segment connecting the central axis and a connection point of the first link with the second link is defined as a first line segment, and a line segment connecting a connection point of the second link with the first link and a connection point of the second link with the dozer blade is defined as a second line segment, and assuming that the dozer blade is in contact with the ground, the minor angle formed by the first line segment and the second line segment may be 75 degrees or more and 105 degrees or less.

[0010] In the dozer blade drive mechanism, the first line segment may be parallel to the ground when it is assumed that the dozer blade is in contact with the ground. The dozer blade drive mechanism for solving the above problem comprises a power generating device that is disposed within a traveling crawler of a construction machine, includes an electric motor, and generates torque; and a connecting member that is connected to the power generating device, is rotatable upon receiving torque from the power generating device, and can attach a dozer blade to the side opposite the connecting point with the power generating device.

[0011] According to the above configuration, the torque of the power generating device can be transmitted to the dozer blade via the connecting member. The dozer blade then rotates in response to the power of the electric motor. That is, according to the above configuration, the dozer blade can be operated using the electric motor as a power source.

[0012] The dozer blade drive mechanism may include two sets of power transmission mechanisms, each set consisting of the power generating device and the connecting member, and the two sets of power transmission mechanisms may be provided corresponding to one and the other of the pair of traveling crawlers in the construction machine.

[0013] The dozer blade drive mechanism is provided in each of the two sets of power transmission mechanisms and includes a universal joint located at the attachment point of the dozer blade on the connecting member and connecting the connecting member to the dozer blade, and a control device that controls the electric motors of the two sets of power transmission mechanisms, and the control device may be capable of individually controlling each of the electric motors of the two sets of power transmission mechanisms.

[0014] The dozer blade drive mechanism may include a driven sprocket that is annular and coaxial with the central axis of rotation of the power generating unit, has a plurality of teeth formed on its outer peripheral surface, and has the power generating unit inserted therethrough, and a bearing that is arranged between the driven sprocket and the power generating unit and supports the driven sprocket rotatably relative to the power generating unit, wherein the driven sprocket is located at an end of the traveling crawler opposite to the driving sprocket for traveling across the center of the traveling crawler, and the connecting member may extend from the point of connection with the power generating unit toward the opposite side to the driving sprocket.

[0015] A dozer blade drive mechanism for solving the above problem is attached to the body of a construction machine and includes a power generating unit that includes an electric motor and generates torque, and a connecting member that is connected to the power generating unit, is rotatable by receiving torque from the power generating unit, and allows a dozer blade to be attached to the side opposite to the connecting point with the power generating unit.

[0016] According to the above configuration, the torque of the power generating device can be transmitted to the dozer blade via the connecting member. The dozer blade then rotates in response to the power of the electric motor. That is, according to the above configuration, the dozer blade can be operated using the electric motor as a power source.

[0017] In the dozer blade drive mechanism, a wall portion of the vehicle body for mounting the power generating device may straddle the center between the pair of crawlers. The dozer blade drive mechanism may include two sets of power transmission mechanisms, each set consisting of the power generating device and the connecting member, and the two sets of power transmission mechanisms may be located on one side and the other side of the center between the pair of crawlers.

[0018] The dozer blade drive mechanism for solving the above problem is attached to an upper body that is rotatable relative to the lower body of the construction machine, and includes a power generating unit that includes an electric motor as a drive source and generates torque, and a connecting member that is connected to the power generating unit, is rotatable by receiving torque from the power generating unit, and can attach a dozer blade to the side opposite the connecting point with the power generating unit.

[0019] According to the above configuration, the torque of the power generating device can be transmitted to the dozer blade via the connecting member. The dozer blade then rotates in response to the power of the electric motor. That is, according to the above configuration, the dozer blade can be operated using the electric motor as a power source.

[0020] In the dozer blade drive mechanism, the construction machine is equipped with a bucket for excavation, and when viewed in a direction parallel to the central axis of rotation of the power generating unit, the bucket may be located on the first direction side when viewed from the connecting point, where the direction in which the dozer blade is located when viewed from the connecting point is defined as a first direction.

[0021] In the dozer blade drive mechanism, the power generating unit has a transmission member that outputs torque corresponding to the rotation of the electric motor, and the transmission member has a first member and a second member that are aligned in a direction along the central axis of rotation of the power generating unit, and the first member has a first flat surface facing the second member and a recess that is recessed from the first flat surface and extends along a first axis parallel to the first flat surface, and the second member may have a second flat surface facing the first flat surface and a convex portion that protrudes from the second flat surface at a position facing the concave portion and extends along the first axis.

[0022] A dozer blade drive mechanism for solving the above problem comprises a connecting member that is rotatably connected to the body of the construction machine and to which a dozer blade can be attached on the side opposite to the point of connection with the body, a power generating device that includes an electric motor as a drive source and generates torque, a conversion mechanism that converts the torque generated by the power generating device into linear movement in a direction along the power central axis when an axis along the top and bottom of the construction machine is taken as the power central axis, and a link mechanism that transmits the linear movement converted by the conversion mechanism as rotational movement of the dozer blade.

[0023] According to the above configuration, the torque of the power generating device can be transmitted to the dozer blade via the link mechanism. The dozer blade then rotates in response to the power of the electric motor. In other words, according to the above configuration, the dozer blade can be operated using the electric motor as a power source.

[0024] In the dozer blade drive mechanism, the conversion mechanism may include a nut that rotates upon receiving torque from the power generating device, a screw shaft that is inserted into the nut, and a plurality of balls that are interposed between the nut and the screw shaft.

[0025] In the dozer blade drive mechanism, the power generating device may have a reducer that changes the rotational speed of the electric motor and outputs the changed rotational speed, the reducer may be cylindrical with the power central axis as its central axis, and may have an output member on one end face side in a direction along the power central axis for outputting torque to the nut, the nut may be connected to the output member of the reducer, and the screw shaft and the nut may be inserted into the reducer.

[0026] In the dozer blade drive mechanism, the power generating device may be connected to the vehicle body so as to be rotatable about a central axis that is parallel to a central axis of rotation of the connecting member. A dozer blade drive mechanism for solving the above problem comprises a connecting member that is rotatably connected to the body of a construction machine and to which a dozer blade can be attached on the side opposite to the point of connection with the body, a power generating unit that includes an electric motor as a drive source and generates torque, and an eccentric cam that receives the torque generated by the power generating unit and rotates around a rotation center axis that is parallel to the rotation center axis of the connecting member, and the cam surface, which is the outer peripheral surface of the eccentric cam, is in contact with the connecting member.

[0027] According to the above configuration, the torque of the power generating unit can be transmitted to the dozer blade through the contact action between the eccentric cam and the connecting member. The dozer blade then rotates in response to the power of the electric motor. In other words, according to the above configuration, the dozer blade can be operated using the electric motor as a power source.

[0028] In the dozer blade drive mechanism, when the eccentric cam is a first eccentric cam, the cam surface is a first cam surface, and a rotation center axis of the first eccentric cam is a first rotation center axis, the dozer blade drive mechanism includes a second eccentric cam that rotates about a second rotation center axis that is parallel to the first rotation center axis and is located on the opposite side of the first eccentric cam across the connecting member, and an interlocking mechanism that interlocks and rotates the first eccentric cam and the second eccentric cam, and the second cam surface that is the outer circumferential surface of the second eccentric cam is a first cam surface that interlocks with the first cam The first eccentric cam and the second eccentric cam may be in contact with the connecting member from the opposite side of the first eccentric cam surface, the first eccentric cam and the second eccentric cam having the same shape and dimensions, and the first eccentric cam and the second eccentric cam may rotate in conjunction with each other so that, when viewed from the first rotation center axis, a direction in which a portion of the first cam surface farthest from the first rotation center axis is located coincides with a direction in which a portion of the second cam surface farthest from the second rotation center axis is located.

[0029] The dozer blade drive mechanism may include a spring that applies a biasing force to the connecting member so that the connecting member rotates in one direction relative to the vehicle body, and the one direction may be the side opposite to the side on which the contact point is located when viewed from the rotation center axis of the eccentric cam, when the distance from the rotation center axis of the eccentric cam to the contact point between the cam surface and the connecting member is minimum.

[0030] A dozer blade drive mechanism for solving the above problems comprises a connecting member that is rotatably connected to the body of a construction machine and has a dozer blade attached to the side opposite the point of connection with the body; a power generating unit that is attached to the dozer blade and includes an electric motor that serves as a drive source and generates torque about a central axis that is parallel to the central axis of rotation of the connecting member; and a link mechanism that connects the power generating unit to the body and transmits the torque generated by the power generating unit as a rotational movement of the dozer blade about the central axis of rotation.

[0031] According to the above configuration, the torque of the power generating device can be transmitted to the dozer blade via the link mechanism. The dozer blade then rotates in response to the power of the electric motor. In other words, according to the above configuration, the dozer blade can be operated using the electric motor as a power source. [Effects of the Invention]

[0032] In the above technical concept, the dozer blade can be operated using an electric motor as a power source. [Brief explanation of the drawings]

[0033] [Figure 1] FIG. 1 is a side view showing a schematic configuration of a backhoe according to a first embodiment. [Figure 2] FIG. 2 is a top view schematically illustrating the backhoe of the first embodiment. [Figure 3] FIG. 3 is a diagram showing the base position of the connecting mechanism of the first embodiment. [Figure 4] FIG. 4 is a diagram showing the posture of the connecting mechanism when the dozer blade of the first embodiment is at the upper limit position of the movable range. [Figure 5] FIG. 5 is a diagram showing the posture of the connecting mechanism when the dozer blade of the first embodiment is at the lower limit position of the movable range. [Figure 6] FIG. 6 is a side view showing a schematic configuration of the backhoe of the second embodiment. [Figure 7] FIG. 7 is a top view showing a schematic configuration of the backhoe of the second embodiment. [Figure 8] FIG. 8 is a perspective view of a first member of the transmission member. [Figure 9] FIG. 9 is a perspective view of a second member of the transmission member. [Figure 10] FIG. 10 is a diagram schematically illustrating an example of a usage mode of the dozer blade according to the second embodiment. [Figure 11] FIG. 11 is a side view showing a schematic configuration of a backhoe according to the third embodiment. [Figure 12]FIG. 12 is a top view showing a schematic configuration of the backhoe of the third embodiment. [Figure 13] FIG. 13 is a side view showing a schematic configuration of a backhoe according to the fourth embodiment. [Figure 14] FIG. 14 is a top view showing a schematic configuration of the backhoe of the fourth embodiment. [Figure 15] FIG. 15 is a diagram schematically illustrating a power generating device according to the fourth embodiment. [Figure 16] FIG. 16 is a top view showing one aspect of the backhoe according to the fourth embodiment. [Figure 17] FIG. 17 is a top view showing one aspect of the backhoe according to the fourth embodiment. [Figure 18] FIG. 18 is a top view showing a modified example of the backhoe of the fourth embodiment. [Figure 19] FIG. 19 is a side view showing a schematic configuration of a backhoe according to the fifth embodiment. [Figure 20] FIG. 20 is a top view showing a schematic configuration of the backhoe of the fifth embodiment. [Figure 21] FIG. 21 is a cross-sectional view that schematically illustrates a dozer blade driving mechanism according to the fifth embodiment. [Figure 22] FIG. 22 is a top view schematically illustrating the link mechanism of the fifth embodiment. [Figure 23] FIG. 23 is a side view showing a state in which the dozer blade of the fifth embodiment has been rotated upward. [Figure 24] FIG. 24 is a side view showing a state in which the dozer blade of the fifth embodiment has been rotated downward. [Figure 25] FIG. 25 is a side view showing a schematic configuration of a backhoe according to the sixth embodiment. [Figure 26] FIG. 26 is a top view showing a schematic configuration of the backhoe of the sixth embodiment. [Figure 27] FIG. 27 is a diagram schematically illustrating a first mode of the dozer blade driving mechanism of the sixth embodiment. [Figure 28]FIG. 28 is a diagram schematically illustrating a second mode of the dozer blade driving mechanism of the sixth embodiment. [Figure 29] FIG. 29 is a diagram showing a modified example of the dozer blade drive mechanism of the sixth embodiment. [Figure 30] FIG. 30 is a side view showing a schematic configuration of the backhoe of the seventh embodiment. [Figure 31] FIG. 31 is a diagram showing a state in which the dozer blade of the seventh embodiment has been rotated upward. [Figure 32] FIG. 32 is a diagram showing a state in which the dozer blade of the seventh embodiment has been rotated downward. DETAILED DESCRIPTION OF THE INVENTION

[0034] First Embodiment A first embodiment of the dozer blade drive mechanism will be described below with reference to the drawings. Note that the drawings may show components enlarged for ease of understanding. Also, the dimensional ratios of the components may differ from those in the actual drawings or from those in other drawings.

[0035] <Overall structure> As shown in FIG. 1 , a backhoe 500, which is a construction machine, includes a vehicle body 520. The vehicle body 520 further includes a lower housing 400 and an upper body 530. The lower housing 400 is also simply referred to as the lower body. The upper body 530 is located on the opposite side of the lower housing 400 from the ground G. The upper body 530 includes a seat for an operator, a battery storage section, and the like. In this embodiment, up, down, front, back, left, and right are defined based on the backhoe 500. That is, the direction in which the upper body 530 is located as viewed from the lower housing 400 is the upward direction, and the opposite direction is the downward direction. Furthermore, a specific direction among directions orthogonal to the upward direction is the forward direction, and the opposite direction is the backward direction. Furthermore, one of the directions orthogonal to both the upward direction and the forward direction is the leftward direction, and the other is the rightward direction. Hereinafter, the front and rear directions may be collectively referred to as the X direction, the left and right directions as the Y direction, and the up and down directions as the Z direction. The upper body 530 is rotatable left and right relative to the lower housing 400, centering on an axis extending substantially in the Z direction.

[0036] The lower housing 400 includes a main housing part 410 and a front housing part 420. The main housing part 410 has an outer shape of, for example, a rectangular parallelepiped. The main housing part 410 houses various mechanisms necessary for operating the backhoe 500. The main housing part 410 is not limited to a box shape, and may have any shape as long as it can accommodate necessary components. The front housing part 420 is located forward of the main housing part 410. The front housing part 420 is fixed to the main housing part 410. As shown in FIG. 2, the front housing part 420 straddles the center of the main housing part 410 in the Y direction. Note that the upper body 530 is not shown in FIG. 2. The outer shape of the front housing part 420 is a rectangular parallelepiped as a whole. As shown in FIG. 1, the outer surface of the front housing part 420 opposite the main housing part 410 is curved in an arc shape so that, for example, the central portion is convex forward when viewed in the Y direction. The interior of the housing front part 420 is hollow.

[0037] As shown in FIGS. 1 and 2, the excavator 500 is equipped with a pair of traveling devices 550. The pair of traveling devices 550 are located on both the left and right sides of the lower housing 400. The traveling devices 550 are equipped with endless belt-like crawlers and an operating mechanism that moves the crawlers. The operating mechanism is located within an area surrounded by the crawlers. Of the traveling devices 550, the operating mechanism is included as one element that constitutes the vehicle body 520.

[0038] As shown in FIG. 1, the excavator 500 is equipped with a work attachment 510. The work attachment 510 is equipped with a columnar boom 515, a columnar work arm 513, and a box-shaped bucket 511. The boom 515 extends forward from an upper body 530. The boom 515 is rotatable up and down relative to the upper body 530, centering on the point where it is connected to the upper body 530. The work arm 513 is connected to the tip of the boom 515. The work arm 513 is rotatable up and down relative to the boom 515, centering on the point where it is connected to the boom 515. The bucket 511 is connected to the tip of the work arm 513. The bucket 511 is rotatable up and down relative to the work arm 513, centering on the point where it is connected to the work arm 513. Note that the work attachment 510 is not shown in FIG. 2.

[0039] As shown in FIG. 1, the excavator 500 includes a dozer blade 300. The dozer blade 300 is located forward relative to the front housing part 420. The dozer blade 300 includes a dozer blade body 310 and a pair of attachment pieces 320. The dozer blade body 310 is plate-shaped. When viewed in the Y direction, the dozer blade body 310 is bent so as to convex rearward at a position midway in the Z direction. As shown in FIG. 2, the dozer blade body 310 is elongated in the Y direction. Note that FIG. 2 illustrates the arrangement of the components when the dozer blade 300 is in the lowermost position shown in FIG. 5, as viewed from above. The pair of attachment pieces 320 are located near the center of the dozer blade body 310 in the Y direction. The pair of attachment pieces 320 extend rearward from the rear surface of the dozer blade body 310. The pair of attachment pieces 320 are spaced apart in the Y direction. 1, the pair of mounting pieces 320 are located within the range in the Z direction where the dozer blade body 310 is present. The pair of mounting pieces 320 are connected to the lower housing 400 via a connecting mechanism 100, which will be described later.

[0040] <Connection mechanism> As shown in FIG. 2, the excavator 500 includes a coupling mechanism 100. The coupling mechanism 100 is also referred to as a dozer blade drive mechanism. The coupling mechanism 100 includes a pair of arms 70. The arms 70 are also referred to as coupling members. The pair of arms 70 are located on both the left and right sides of the lower housing 400. The pair of arms 70 are symmetrical in the Y direction. Therefore, only one of the pair of arms 70 will be described in detail below. The arm 70 is elongated in the front-to-rear direction. A first support shaft 21 passes through one end of the arm 70. The first support shaft 21 is fixed to the housing main part 410. In other words, the arm 70 is connected to the housing main part 410 via the first support shaft 21. The first support shaft 21 is cylindrical. A central axis 21A of the first support shaft 21 extends substantially in the Y direction. As shown in FIG. 1 , the arm 70 is rotatable relative to the main housing part 410 around the first support shaft 21. That is, the central axis 21A of the first support shaft 21 is the central axis of rotation of the arm 70. The arm 70 extends linearly forward from the first support shaft 21. The dozer blade 300 can be attached to the front end of the arm 70, i.e., the side of the arm 70 opposite the connection point with the main housing part 410, using an attachment means. Various attachment means can be used, such as bolting or welding. In this embodiment, the rear surface of the dozer blade body 310 is attached to the front end of the arm 70. Note that in FIG. 1 , the arm 70 is partially cut away to make it easier to understand the positional relationship of each component.

[0041] As shown in FIG. 1, it is assumed that the ground G on which the crawler of the traveling device 550 travels is flat, and that the flat ground G continues forward of the crawler along the underside of the crawler. Assuming that the excavator 500 is positioned on such ground G, it is assumed that the lower end of the dozer blade body 310 is in contact with the ground G. This assumption is referred to as the base assumption. In this base assumption, the first support shaft 21 is located near the center of the dozer blade body 310 in the Z direction, slightly above the center. Therefore, the arm 70 is positioned at a slight downward angle so that it is positioned more downward as it moves forward.

[0042] <Power Generation Device> 1, the connecting mechanism 100 includes a power generating device 30. As shown in FIG. 2, the power generating device 30 includes a motor 31, a reducer 35, and a transmission member 36.

[0043] The motor 31 is a drive source of the power generating device 30. The motor 31 includes a housing 32 and an output shaft 33. The motor 31 is an electrically powered motor that operates in response to power supplied from a battery (not shown). The housing 32 is fixed inside the front housing portion 420. Most of the output shaft 33 is located inside the housing 32. A portion of the output shaft 33 protrudes to the right from the housing 32. The output shaft 33 is cylindrical. The output shaft 33 is rotatable relative to the housing 32. The output shaft 33 rotates about its own central axis 31A. The central axis 31A of the output shaft 33 extends approximately in the Y direction. In other words, the central axis 31A of the output shaft 33 is approximately parallel to the central axis 21A of the first support shaft 21 and, therefore, the central axis of rotation of the arm 70. The output shaft 33 is rotatable in both forward and reverse directions in response to power supplied to the motor 31. Hereinafter, the central axis 31A of the output shaft 33 may be referred to as the central axis 31A of the motor 31. As shown in FIG. 1, the central axis 31A of the output shaft 33 is located above the central axis 21A of the first support shaft 21.

[0044] As shown in FIG. 2 , the reducer 35 is adjacent to the motor 31 in the direction along the central axis 31A of the output shaft 33 of the motor 31. In this embodiment, the reducer 35 is located to the right of the motor 31. The reducer 35 is housed in the front housing part 420. The reducer 35 is connected to the output shaft 33 of the motor 31. The torque of the output shaft 33 of the motor 31 is input to the reducer 35. The reducer 35 amplifies the torque of the output shaft 33 of the motor 31 at a predetermined ratio and outputs the amplified torque. The reducer 35 may be, for example, an eccentric oscillating gear type or a planetary gear type. Any type of reducer 35 may be used as long as it is configured to amplify and output the torque from the motor 31.

[0045] The transmission member 36 is connected to the reducer 35. In this embodiment, the transmission member 36 is located to the right of the reducer 35. For example, the transmission member 36 is located in a position exposed from the front part 420 of the housing. For example, the transmission member 36 is plate-shaped. The torque output by the reducer 35 is input to the transmission member 36. The transmission member 36 rotates in response to the torque from the reducer 35. The rotation center axis of the transmission member 36 coincides with the central axis 31A of the motor 31. In other words, the transmission member 36 outputs torque centered on the central axis 31A of the motor 31. As described above, the power generating device 30 uses the motor 31 as a drive source and performs the function of generating torque centered on the central axis 31A of the motor 31.

[0046] <Link mechanism> As shown in FIG. 1, the connecting mechanism 100 includes a link mechanism 40. The link mechanism 40 includes a first link 50 and a second link 60. Hereinafter, a plan view of the excavator 500 in a direction parallel to the central axis 31A of the motor 31 will be referred to as a specific plan view. As shown in FIG. 1, the first link 50 is a linear link component in the specific plan view. On the other hand, as shown in FIG. 2, the first link 50 has a crank shape that is bent twice midway when viewed in the Z direction. That is, the first link 50 includes a connection portion 51 that extends linearly in the front-to-rear direction, a step portion 52 that is bent relative to the connection portion 51, and an extension portion 53 that extends linearly in the front-to-rear direction from the end of the step portion 52 opposite the connection portion 51. The connection portion 51 and the extension portion 53 are parallel to each other and are offset in the X direction. In this embodiment, the connection portion 51 is located on the right side of the power generating device 30. The connection portion 51 is fixed to the transmission member 36 of the power generating unit 30. The connection portion 51 operates integrally with the transmission member 36. In other words, the connection portion 51, and therefore the entire first link 50, receives torque from the power generating unit 30 and rotates about the central axis 31A of the motor 31. The end of the connection portion 51 closer to the stepped portion 52 extends forward of the front housing portion 420. The stepped portion 52 and the extension portion 53 are located forward of the front housing portion 420. The extension portion 53 is located near the center of the front housing portion 420 in the Y direction.

[0047] As shown in FIG. 1, the second link 60 is a linear link component in a specific plan view. On the other hand, as shown in FIG. 2, the second link 60 includes a U-shaped leg 61 and a trunk 62 extending linearly from the bottom of the U-shape of the leg 61 toward the opposite side of the fork of the U-shape when viewed in the Z direction. The end of the extension 53 of the first link 50 is located between the fork of the U-shape of the leg 61. A second support shaft 22 penetrates the leg 61 and the extension 53 of the first link 50. In other words, the leg 61 and the extension 53 of the first link 50 are connected via the second support shaft 22. The second support shaft 22 is prevented from coming off the leg 61 and the extension 53 by a retaining means (not shown). The second support shaft 22 is cylindrical. A central axis 22A of the second support shaft 22 extends substantially in the Y direction. That is, the central axis 22A of the second support shaft 22 is substantially parallel to the central axis 21A of the first support shaft 21. The leg 61 and the extension 53 of the first link 50 are rotatable relative to the second support shaft 22. At the same time, the leg 61 and the extension 53 of the first link 50 are rotatable relative to each other around the second support shaft 22.

[0048] The end of the body 62 of the second link 60 opposite the leg 61 is located between a pair of attachment pieces 320 of the dozer blade 300. A third support shaft 23 penetrates the pair of attachment pieces 320 and the body 62. That is, the body 62 and the attachment pieces 320 are connected via the third support shaft 23. The third support shaft 23 is prevented from coming off the body 62 and the attachment pieces 320 by a retaining means (not shown). The third support shaft 23 is cylindrical. A central axis 23A of the third support shaft 23 extends substantially in the Y direction. That is, the central axis 23A of the third support shaft 23 is substantially parallel to the central axis 22A of the second support shaft 22. The body 62 and the attachment pieces 320 are rotatable relative to the third support shaft 23. At the same time, the body 62 and the attachment pieces 320 are rotatable relative to each other about the third support shaft 23. In this way, the second link 60 is rotatable relative to both the first link 50 and the dozer blade 300 .

[0049] As described above, the first link 50 and the second link 60 connect the power generating unit 30 and the dozer blade 300. At the same time, the second link 60 is rotatable relative to both the first link 50 and the dozer blade 300. As a result of this connection structure, when the power generating unit 30 generates torque, the first link 50 and the second link 60 can transmit the torque to the dozer blade 300 through the mutual rotational movement. The associated operation of the dozer blade 300 will be described in the section on operation of the embodiment below.

[0050] <Positional and dimensional relationships> The positional and dimensional relationships of the components of the coupling mechanism 100 will be described. As shown in FIG. 1 , in a specific plan view, a line segment connecting the central axis 21A of the first support shaft 21 and the central axis 23A of the third support shaft 23 is referred to as the arm line segment LX. The central axis 21A of the first support shaft 21 corresponds to the connection point of the arm 70 with the housing main section 410. The central axis 23A of the third support shaft 23 corresponds to the connection point of the second link 60 with the dozer blade 300. Furthermore, in a specific plan view, a line segment connecting the central axis 31A of the motor 31 and the central axis 23A of the third support shaft 23 is referred to as the link line segment. The positional and dimensional relationships of the components of the coupling mechanism 100 are determined so that the link line segment is shorter than the arm line segment LX.

[0051] In detail, in the connecting mechanism 100, the position of each support shaft and the length of each link and arm 70 are determined so as to satisfy the following first condition in a specific plan view. The first condition is that, in the X direction, the central axis 31A of the motor 31 is located closer to the dozer blade 300 than the center of the arm line segment LX. In other words, it can be said that the central axis 31A of the motor 31 is located further forward than the center of the arm line segment LX. In this embodiment, the position of each support shaft and the length of each link and arm 70 are determined so as to satisfy the first condition throughout the entire movable range of the dozer blade 300.

[0052] In this embodiment, when the base assumption is satisfied, the arm line segment LX extends substantially in the X direction. Therefore, when the base assumption is satisfied, the first condition is satisfied when the central axis 31A of the motor 31 is located closer to the dozer blade 300 than the center of the arm line segment LX in the direction along the arm line segment LX.

[0053] In the connecting mechanism 100, the dimensional relationship between the first link 50 and the second link 60 is determined to satisfy the following second condition. As shown in FIG. 1 , in a specific plan view, a line segment connecting the central axis 31A of the motor 31 and the central axis 22A of the second support shaft 22 is referred to as a first line segment L1. The central axis 22A of the second support shaft 22 corresponds to the connection point of the first link 50 with the second link 60. In a specific plan view, a line segment connecting the central axis 22A of the second support shaft 22 and the central axis 23A of the third support shaft 23 is referred to as a second line segment L2. The central axis 22A of the second support shaft 22 corresponds to the connection point of the second link 60 with the first link 50. As described above, the central axis 23A of the third support shaft 23 corresponds to the connection point of the second link 60 with the dozer blade 300. The second condition is that the length of the first line segment L1 is set to a predetermined value that is 150% or more and 200% or less of the length of the second line segment L2.

[0054] In the connecting mechanism 100, the position of each support shaft and the length of each link and arm 70 are determined to satisfy the following third condition. The third condition is that, assuming that the base assumption is established, the minor angle θ formed by the first line segment L1 and the second line segment L2 is greater than or equal to 75 degrees and less than or equal to 105 degrees in a specific planar view. Specifically, the third condition is that all of the following three requirements are satisfied. The first requirement is that, when the base assumption is established, the central axis 31A of the motor 31 and the central axis 22A of the second support shaft 22 are located at approximately the same position in the Z direction. In other words, in a specific planar view, it can be said that the first line segment L1 extends approximately in the X direction and is parallel to the ground G. The second requirement is that, when the base assumption is established, the central axis 23A of the third support shaft 23 is located below the central axis 22A of the second support shaft 22. The third requirement is that, when the base assumption is satisfied, the central axis 22A of the second support shaft 22 and the central axis 23A of the third support shaft 23 are located at approximately the same position in the X direction. In other words, in the specific planar view, it can be said that the second line segment L2 extends approximately in the Z direction. In this embodiment, by satisfying the third condition, the minor angle θ is approximately 90 degrees. Note that the minor angle θ formed by the first line segment L1 and the second line segment L2 is the angle formed by the first line segment L1 and the second line segment L2 that is smaller than 180 degrees.

[0055] <Operation of the First Embodiment> The lifting and lowering operation of the dozer blade 300 will now be described. The clockwise direction on the plane of FIG. 3, that is, the clockwise direction when the backhoe 500 is viewed from the left in a specific plane, is referred to as the first direction V1, and the counterclockwise direction is referred to as the second direction V2. Hereinafter, the posture of the components of the connecting mechanism 100 and the dozer blade 300 when the base assumption shown in FIG. 3 is established is referred to as the base posture. In this base posture, the first support shaft 21 is positioned slightly above the third support shaft 23 in the Z direction. As described above, the arm line segment LX extends approximately in the X direction.

[0056] Assume now that the components of the connecting mechanism 100 are in the base position. Assume that the output shaft 33 of the motor 31 rotates in the first direction V1 from this position. Then, as shown by arrow P1 in FIG. 4 , the first link 50 rotates upward about the central axis 31A of the motor 31. At the same time, the second link 60, the dozer blade 300, and the arm 70 move upward. At this time, the dozer blade 300 rotates upward together with the arm 70 about the first support shaft 21. In other words, the dozer blade 300 rises. While the dozer blade 300 rises from the base position, the minor angle θ between the first line segment L1 and the second line segment L2 in the specific plan view gradually decreases. When the dozer blade 300 reaches the upper limit of its movable range, the minor angle θ between the first line segment L1 and the second line segment L2 in the specific plan view is, for example, approximately 70 degrees. At this upper limit position, the third support shaft 23 is positioned higher than the first support shaft 21. The second support shaft 22 is positioned even higher than the third support shaft 23.

[0057] As shown in FIG. 3, it is assumed that the components of the connecting mechanism 100 are again in the base position. From this state, it is assumed that the output shaft 33 of the motor 31 is rotated in the second direction V2. For example, when the work attachment 510 is used to dig into the ground G, the excavator 500 can move the dozer blade 300 downward below an imaginary plane formed by extending the bottom surface of the crawler. When the output shaft 33 of the motor 31 is rotated in the second direction V2, the first link 50 rotates downward about the central axis 31A of the motor 31, as shown by arrow P2 in FIG. 5. At the same time, the second link 60, the dozer blade 300, and the arm 70 move downward. At this time, the dozer blade 300 rotates downward together with the arm 70 about the first support shaft 21. In other words, the dozer blade 300 descends. While the dozer blade 300 descends from the base position, the minor angle θ formed by the first line segment L1 and the second line segment L2 in the specific plan view gradually increases. When the dozer blade 300 reaches the lower limit position of its movable range, the minor angle θ formed by the first line segment L1 and the second line segment L2 in the specific plan view is, for example, approximately 150 degrees. At this lower limit position, the second support shaft 22 is positioned lower than the first support shaft 21. The third support shaft 23 is positioned further downward than the second support shaft 22.

[0058] As described above, the first link 50 and the second link 60 function to transmit the torque generated by the power generating device 30 as a rotational movement of the dozer blade 300 about the central axis 21A of the first support shaft 21.

[0059] <Effects of the first embodiment> (1-1) According to the configuration of this embodiment, the rotation of the output shaft 33 of the motor 31 can be transmitted to the dozer blade 300 via the first link 50 and the second link 60. This allows the dozer blade 300 to be raised and lowered. That is, according to the configuration of this embodiment, the dozer blade 300 can be raised and lowered using the motor 31 as a power source. In adopting such an electric lifting mechanism for the dozer blade 300, in this embodiment, the positions and dimensions of the components of the connecting mechanism 100 are determined to satisfy the first condition. That is, as shown in FIG. 1 , in the X direction, the central axis 31A of the motor 31 is located closer to the dozer blade 300 than the center of the arm line segment LX. In other words, in this embodiment, the power generating device 30 including the motor 31 is located relatively close to the dozer blade 300. Here, for example, to realize the raising and lowering of the dozer blade 300 using the motor 31 as a power source, it is conceivable to provide the power generating device 30 near the rear end of the arm 70 and apply torque to the rear end of the arm 70 to rotate the arm 70. Compared to the configuration of such a comparative example, in the configuration of this embodiment, the distance from the central axis 31A of the motor 31 to a location, such as the third support shaft 23, where the torque of the power generating device 30 acts on the dozer blade 300 is shorter. In such a configuration of this embodiment, the torque output by the motor 31 and therefore the power generating device 30 can be reduced when raising and lowering the dozer blade 300. Reducing the torque of the power generating device 30 contributes to the miniaturization of the power generating device 30.

[0060] (1-2) In this embodiment, the dimensional relationship between the first link 50 and the second link 60 is determined so as to satisfy the second condition. That is, the length of the first line segment L1 is 150% or more and 200% or less of the length of the second line segment L2. In this case, the dimension of the first link 50 in the radial direction centered on the central axis 31A of the motor 31 can be secured to be appropriately large. This contributes to increasing the movable range of the dozer blade 300.

[0061] (1-3) During use of the excavator 500, a load may be input to the dozer blade 300 from the front side due to a collision with earth and sand, etc. This load may be input from the dozer blade 300 to the connecting mechanism 100. Depending on the configuration of the connecting mechanism 100, most of this load may be input to the power generating device 30. If most of the external load may be input to the power generating device 30, it is necessary to provide the power generating device 30 with a structure to deal with the load in advance so that the power generating device 30 can bear such a large load. An example of such a structure is to enlarge the bearings and supports provided in the reducer 35. However, adopting such a structure to deal with the load may result in a concern that the power generating device 30 may become larger.

[0062] In this regard, in the configuration of this embodiment, the positions and dimensions of the components of the connecting mechanism 100 are determined so as to satisfy the third condition. The third condition includes the following second requirement. Specifically, as shown in FIG. 1 , when the lower end of the dozer blade body 310 is in contact with the ground G, the third support shaft 23 is positioned below the second support shaft 22, and the second link 60 extends generally vertically. In this configuration, assume that a load acts on the dozer blade 300 from the front side. Here, the load acting on the dozer blade 300 from the front side has a component mainly in the X direction. Therefore, this load is unlikely to act as a force that moves each component in a direction intersecting the X direction. In other words, this load is unlikely to act as a force that moves the second link 60, which extends generally in the Z direction, and thus the second support shaft 22, located at its upper end, upward, and therefore hardly contributes to the rotation of the first link 50. Furthermore, there is a gap between the through-hole through which the support shaft of each link passes and the outer circumferential surface of the support shaft, sufficient for both to rotate. Even if the second link 60 moves slightly due to a load acting on the dozer blade 300, the movement of the second link 60 is prevented from being transmitted to the first link 50 by the gap. Due to these factors, even if a load acts on the dozer blade 300 from the front side, this load is unlikely to be input to the power generator 30. On the other hand, as described above, the load acting on the dozer blade 300 from the front side has a component in the X direction. Therefore, this load acts mainly on the first support shaft 21, which is located rearward of the dozer blade 300, and thus on the main housing part 410. The main housing part 410 then absorbs most of this load. Overall, in this embodiment, when a load acts on the dozer blade 300 from the front side, the force associated with the load can be prevented from being input to the power generator 30. Therefore, the power generating device 30 can be prevented from becoming large.

[0063] (1-4) By satisfying the third condition, the minor angle θ between the first line segment L1 and the second line segment L2 is approximately 90 degrees. In other words, in the base position, the first link 50 and the second link 60 are approximately perpendicular to each other. When the first link 50 and the second link 60 are in this positional relationship, there is a considerable margin for the first link 50 and the second link 60 to rotate relative to each other, regardless of whether the dozer blade 300 in the base position is moved up or down. Therefore, with the configuration of this embodiment, it is possible to ensure a sufficient range of movement both upward and downward from the base position.

[0064] (1-5) In this embodiment, since all three requirements of the third condition are satisfied, the second link 60 is arranged to extend vertically approximately along the Z direction. As described above, the load acting on the dozer blade 300 from the front side has an X-direction component. Therefore, in the configuration of this embodiment in which the second link 60 is arranged so as to be perpendicular to this load, in relation to (1-3), it is possible to significantly prevent the load on the dozer blade 300 from reaching the power generating unit 30.

[0065] <Modification of the first embodiment> The first embodiment can be modified as follows: The first embodiment and the following modifications can be combined and implemented within the scope of technical compatibility.

[0066] The third condition does not necessarily include the first requirement. In other words, when the base assumption is true, the first line segment L1 may be tilted to some extent with respect to the X direction in the specific planar view. For example, the first line segment L1 may be tilted approximately 15 degrees downward or upward with respect to the X direction in the specific planar view. Furthermore, the third condition does not necessarily include the third requirement. In other words, when the base assumption is true, the second line segment L2 may be tilted to some extent with respect to the Z direction in the specific planar view. Either the first requirement or the third requirement may be omitted from the third condition, or both may be omitted. As a result of changing the third condition, when the base assumption is true, the minor angle θ formed by the first line segment L1 and the second line segment L2 in the specific planar view may deviate from the range between 75 degrees and 105 degrees. Even in this case, the effect of (1-3) can be achieved if the third condition includes the second requirement. Furthermore, in view of the second requirement, the base assumption that the lower end of the dozer blade body 310 is in contact with the ground G may be abolished. Here, the dozer blade 300 is basically often used with the lower end of the dozer blade body 310 in contact with the ground G. However, even when the lower end of the dozer blade body 310 is not in contact with the ground G, a load may be input to the dozer blade 300 from the front side. Even when the lower end of the dozer blade body 310 is not in contact with the ground G, as long as the first line segment L1 and the second line segment L2 intersect and the central axis 23A of the third support shaft 23 is located below the central axis 22A of the second support shaft 22 in the specific plan view, this is suitable for suppressing a force acting on the dozer blade 300 from the front side from reaching the power generating device 30.

[0067] When determining the positions of the support shafts in the connecting mechanism 100 and the lengths of the links and arms 70, the third condition may be omitted. The second condition is not limited to the example of the above embodiment. The second condition requires that the length of the first line segment L1 be set to a predetermined value that is 50% or more and 200% or less of the length of the second line segment L2. If such a second condition is set, a correspondingly large movable range of the dozer blade 300 can be ensured.

[0068] - When determining the dimensional relationship between each link, the second condition may be abolished. It is not essential that the first condition be satisfied throughout the entire movable range of the dozer blade 300. For example, depending on the setting of the upper limit position or the lower limit position of the dozer blade 300, the first condition may not be satisfied within the movable range of the dozer blade 300. It is sufficient that the first condition is satisfied in at least a part of the movable range of the dozer blade 300, such as the base position.

[0069] The configuration of the link mechanism 40 is not limited to the example of the above embodiment. The dimensions and shape of each link component can be changed as appropriate from the example of the above embodiment. Furthermore, the number of link components constituting the link mechanism 40 can also be changed as appropriate from the example of the above embodiment. The link mechanism 40 only needs to be configured to be able to transmit the torque generated by the power generating device 30 as a rotational movement of the dozer blade 300 about the central axis 21A of the first support shaft 21.

[0070] The configuration of the arm 70 is not limited to the example of the above embodiment. The dimensions and shape of the arm 70 can be modified as appropriate from the example of the above embodiment. The arm 70 only needs to be rotatably connected to the vehicle body 520 and be able to attach the dozer blade 300 to the side opposite the connection point with the vehicle body 520. The manner in which the arm 70 is attached to the dozer blade 300 can be modified as appropriate. Furthermore, as will be described in the modified examples below, the connection point on the vehicle body 520 side for connecting the arm 70 to the vehicle body 520 is not limited to the main housing part 410 or the lower housing 400.

[0071] The configuration of the power generating device 30 is not limited to the example of the above embodiment. The power generating device 30 may be configured to include an electric motor 31 as a drive source and to generate torque centered on a central axis parallel to the central axis of rotation of the arm 70. For example, the left and right positions of the motor 31 and the reducer 35 may be interchanged from those of the above embodiment. Accordingly, the configuration for connecting the power generating device 30 and the link mechanism 40 may be changed. The transmission member 36 may be eliminated from the power generating device 30. The reducer 35 and the link mechanism 40 may be connected so that the torque output by the reducer 35 is directly transmitted to the link mechanism 40.

[0072] The structure of the vehicle body 520 for attaching the power generating unit 30 to the vehicle body 520 is not limited to the example of the above embodiment. As long as the power generating unit 30 can be attached to the vehicle body 520, the structure is not critical.

[0073] The manner in which the arm 70 is connected to the vehicle body 520 is not limited to the example in the above embodiment. For example, the arm 70 and the first support shaft 21 may be fixed. The first support shaft 21 may then be connected to the main housing part 410 so that the first support shaft 21 is rotatable relative to the main housing part 410. As long as the arm 70 can be connected to the vehicle body 520 so that the arm 70 is rotatable relative to the vehicle body 520, the manner in which the arm 70 is connected is not important.

[0074] As with the above-described modified example, the manner in which the first link 50 and the second link 60 are connected is not limited to the example of the above-described embodiment. For example, the second support shaft 22 may be fixed to either the first link 50 or the second link 60. It is sufficient that the first link 50 and the second link 60 can be connected so that they can rotate relative to each other. The same applies to the manner in which the second link 60 is connected to the dozer blade 300.

[0075] The arrangement of the link mechanism 40, the arm 70, and the power generating unit 30 is not limited to the example of the above embodiment. For example, the arm 70 may be provided on the outside in the Y direction relative to the traveling unit 550. In other words, the arm 70 may be located on the opposite side of the traveling unit 550 from the lower housing 400. The arm 70 may be connected to a wall of the operating mechanism of the traveling unit 550. For example, the arrangement of the link mechanism 40 and the power generating unit 30 may be changed from the example of the above embodiment in accordance with such a change in the arrangement of the arm 70. Depending on such a change in arrangement, the positional relationship between the link mechanism 40, the arm 70, and the power generating unit 30 may be changed from the example of the above embodiment. Even in this case, it is sufficient that the first condition is satisfied.

[0076] The range of movement of the dozer blade 300 is not limited to the example of the above embodiment. The range of movement of the dozer blade 300 may vary depending on the configuration of the link mechanism 40, the arm 70, etc. The configuration of the dozer blade 300 is not limited to the example of the above embodiment. For example, the structure for attaching the link mechanism 40 to the dozer blade 300 may be different from that of the example of the above embodiment. The dozer blade 300 may be configured to perform the required purpose, such as leveling, excavation, and shoveling soil.

[0077] The construction machine to which the coupling mechanism 100 for the dozer blade 300 is applied is not limited to the example of the above embodiment. For example, the coupling mechanism 100 can also be applied to a bulldozer or a compact track loader.

[0078] In the above embodiments, if an object is made up of multiple objects, the multiple objects may be integrated, and conversely, if an object is made up of a single object, it may be divided into multiple objects. Regardless of whether the objects are integrated or not, it is sufficient that the object of the invention can be achieved.

[0079] Second Embodiment A second embodiment of the dozer blade drive mechanism will be described below with reference to Figures 6 to 10. Note that the drawings may show components enlarged to facilitate understanding. The dimensional ratios of the components may differ from the actual ones or from those in other drawings. In Figures 6 to 10, parts that are the same as or function substantially the same as those in Figures 1 to 5 are denoted by the same reference numerals as in Figures 1 to 5. In the following description, parts that overlap with the first embodiment may be omitted or simplified as appropriate.

[0080] As shown in FIG. 6, an excavator 600, which is a construction machine, includes a vehicle body 603. The vehicle body 603 includes a lower body 605 and an upper body 530. The configuration of the lower body 605 is substantially the same as that of the main housing 410 of the first embodiment. The configuration of the upper body 530 is the same as that of the first embodiment. The upper body 530 is located on the opposite side of the ground from the lower body 605. Note that in this embodiment, up, down, left, right, front, and rear are defined in the same way as in the first embodiment. The upper body 530 is rotatable left and right relative to the lower body 605 about an axis extending substantially in the Z direction.

[0081] As shown in FIG. 6, the backhoe 600 is equipped with a work attachment 510. The configuration of the work attachment 510 is the same as that of the first embodiment. The backhoe 600 is also equipped with a dozer blade 608. The dozer blade 608 is located forward of the lower body 605. The dozer blade 608 is plate-shaped. When viewed in the Y direction, the dozer blade 608 is bent so as to convex backward at a position midway in the Z direction. As shown in FIG. 7, the dozer blade 608 is elongated in the Y direction. Note that the upper body 530 and the work attachment 510 are not shown in FIG. 7.

[0082] <Traveling device> As shown in FIG. 7, the excavator 600 is equipped with a pair of traveling devices 610. The pair of traveling devices 610 are located on both the left and right sides of the lower body 605. The pair of traveling devices 610 are configured symmetrically. Therefore, in the following, the traveling device 610 located on the left side of the lower body 605 will be described as an example.

[0083] 6, the traveling device 610 includes an operating mechanism 615 and a traveling crawler 611. The operating mechanism 615 includes a crawler frame 620, a plurality of rollers 616, an output unit 617, and a drive sprocket 618. The operating mechanism 615 is included as one element of the traveling device 610 that constitutes the vehicle body 603.

[0084] As shown in FIG. 7, the crawler frame 620 includes a first side wall 621 and a second side wall 622. The first side wall 621 and the second side wall 622 are aligned in the Y direction. The first side wall 621 is located on the opposite side of the lower body 605, with the second side wall 622 sandwiched between them. Both the first side wall 621 and the second side wall 622 are rectangular plate-shaped. Both the first side wall 621 and the second side wall 622 are elongated in the X direction. The main surfaces of the first side wall 621 and the second side wall 622 face each other. The main surfaces are the outer surfaces of the plate-shaped members with the largest area. The first side wall 621 and the second side wall 622 are connected to each other via an upper wall (not shown).

[0085] The crawler frame 620 has a front wall 623. The front wall 623 extends forward from the front end of the second side wall 622. The front wall 623 has a storage hole 623A. The storage hole 623A penetrates the front wall 623 in the Y direction. The outer shape of the storage hole 623A is cylindrical.

[0086] 6, the crawler frame 620 has a rear wall 624. Although not shown in detail, the rear wall 624 extends rearward from the rear end of the second side wall 622. Although detailed illustration is omitted, the rollers 616 are positioned between the first side wall 621 and the second side wall 622. The number of rollers 616 is, for example, three. The rollers 616 are aligned in the X direction. The rollers 616 are rotatably supported by the first side wall 621 and the second side wall 622. The central axis of rotation of each roller 616 extends in the Y direction.

[0087] The output unit 617 is supported by the rear wall 624. The output unit 617 includes an electric motor and a reducer that reduces the rotation of the motor and outputs the reduced speed. The motor can rotate in both forward and reverse directions. In other words, the output unit 617 can output torque in both forward and reverse directions.

[0088] The drive sprocket 618 is attached to the output unit 617. The drive sprocket 618 is annular. The output unit 617 is fixed to a central hole of the drive sprocket 618. The central axis of the drive sprocket 618 extends in the Y direction. A plurality of teeth are formed on the outer circumferential surface of the drive sprocket 618. The plurality of teeth are arranged at equal intervals in the circumferential direction around the central axis of the drive sprocket 618. The drive sprocket 618 rotates in response to the torque output by the output unit 617.

[0089] As shown in Fig. 6, the traveling crawler 611 is in the form of an endless belt. The traveling crawler 611 is made of, for example, metal or rubber. The traveling crawler 611 surrounds the operating mechanism 615. The traveling crawler 611 extends in the X direction as a whole and is open on both sides in the Y direction. The traveling crawler 611 has a constant width in the Y direction.

[0090] 7, a plurality of grooves 611A are recessed in the inner circumferential surface of the traveling crawler 611. The grooves 611A are located in the center of the traveling crawler 611 in the Y direction. The plurality of grooves 611A are arranged at equal intervals around the entire circumference of the traveling crawler 611.

[0091] As shown in Fig. 6, a drive sprocket 618 is located at the rear end of the traveling crawler 611. The teeth of the drive sprocket 618 mesh with grooves 611A of the traveling crawler 611. A plurality of rollers 616 are located near the center of the traveling crawler 611 in the X direction. The outer circumferential surfaces of the rollers 616 are in contact with the inner circumferential surface of the traveling crawler 611. A driven sprocket 637, which will be described later, is located at the forefront of the traveling crawler 611.

[0092] <Dozer blade drive mechanism> As shown in Fig. 7, the excavator 600 is equipped with a dozer blade drive mechanism 600A. The dozer blade drive mechanism 600A is equipped with two sets of power transmission mechanisms 630. The two sets of power transmission mechanisms 630 are provided corresponding to one and the other of a pair of traveling crawlers 611, respectively. In other words, a power transmission mechanism 630 is provided for each traveling crawler 611. The two sets of power transmission mechanisms 630 are configured symmetrically. Therefore, the power transmission mechanism 630 located on the left side of the lower body 605 will be described below as an example of the two sets of power transmission mechanisms 630.

[0093] The power transmission mechanism 630 is configured as a set of a power generating device 631, a connecting member 633, a universal joint 635, a driven sprocket 637, and a bearing 639. The power generating device 631 includes a motor 31, a reducer 35, and a transmission member 640. The motor 31 is located in a front portion of the crawler frame 620. The motor 31 is a drive source for the power generating device 30. The motor 31 includes a housing 32 and an output shaft 33. The motor 31 is an electrically driven motor that operates in response to power supplied from a battery (not shown). The housing 32 is fixed to a receiving hole 623A in the front wall 623. That is, the housing 32 is located within the range of the traveling crawler 611 in the Y direction. The housing 32 is cylindrical as a whole. The central axis of the housing 32 extends in the Y direction. Most of the output shaft 33 is located inside the housing 32. A portion of the output shaft 33 protrudes from the housing 32 toward the opposite side of the lower body 605. The output shaft 33 is cylindrical. The central axis 31A of the output shaft 33 extends in the Y direction. The output shaft 33 is rotatable relative to the housing 32. The output shaft 33 rotates about its own central axis 31A. The output shaft 33 is rotatable in both forward and reverse directions depending on the power supply to the motor 31. Hereinafter, the central axis 31A of the output shaft 33 may be referred to as the central axis 31A of the motor 31.

[0094] The reducer 35 is adjacent to the motor 31 in the direction along the central axis 31A of the motor 31. The reducer 35 is located on the opposite side of the motor 31 from the lower body 605. In the Y direction, the reducer 35 is located within the range of the traveling crawler 611. The reducer 35 is cylindrical overall. The central axis of the reducer 35 substantially coincides with the central axis 31A of the motor 31. The reducer 35 is connected to the output shaft 33 of the motor 31. The torque of the output shaft 33 of the motor 31 is input to the reducer 35. The reducer 35 amplifies the torque of the output shaft 33 of the motor 31 at a predetermined ratio and outputs the amplified torque. The reducer 35 may be, for example, an eccentric oscillating gear type or a planetary gear type. Any type of reducer 35 may be used as long as it is capable of amplifying and outputting the torque from the motor 31.

[0095] The transmission member 640 is adjacent to the reducer 35 in the direction along the central axis 31A of the motor 31. The transmission member 640 is located on the opposite side of the reducer 35 from the motor 31. In addition, in the Y direction, the transmission member 640 is located in a position exposed from the traveling crawler 611. The transmission member 640 is connected to the reducer 35. The transmission member 640 is cylindrical overall. The central axis of the transmission member 640 approximately coincides with the central axis 31A of the motor 31. Details of the transmission member 640 will be described later. The torque output by the reducer 35 is input to the transmission member 640. The transmission member 640 rotates upon receiving the torque from the reducer 35. The central axis of the rotation of the transmission member 640 coincides with the central axis 31A of the motor 31. In other words, the transmission member 640 outputs torque centered on the central axis 31A of the motor 31 in response to the rotation of the motor 31 and therefore the reducer 35. As described above, the power generating device 631 uses the motor 31 as a drive source to generate torque centered on the central axis 31A of the motor 31. Hereinafter, the central axis 31A of the motor 31 may be referred to as the central axis 31A of the power generating device 631. The central axis 31A of the motor 31 may also be referred to as the central axis of rotation of the power generating device 631. Note that FIG. 6 shows only the outer shape of the transmission member 640 of the power generating device 631.

[0096] <Connecting member> As shown in FIG. 7 , the connecting member 633 is adjacent to the transmission member 640 in the direction along the central axis 31A of the motor 31. The connecting member 633 is located on the opposite side of the transmission member 640 from the reducer 35. The connecting member 633 includes a rod-shaped main body 633A and a connecting portion 633B located at one longitudinal end of the main body 633A. The connecting portion 633B is plate-shaped. A main surface of the connecting portion 633B faces the end face of the transmission member 640 on the opposite side from the reducer 35. The connecting portion 633B is connected to the transmission member 640 by an attachment means. Various attachment means can be used, such as bolting or welding.

[0097] 6, the main body 633A of the connecting member 633 extends linearly forward from the connecting portion 633B. In other words, the connecting member 633 extends from the point of connection with the power generating unit 631 toward the opposite side from the drive sprocket 618. The dozer blade 608 can be attached to the front end of the main body 633A of the connecting member 633, i.e., to the side of the connecting member 633 opposite to the point of connection with the power generating unit 631. In this embodiment, the connecting member 633 is attached to the dozer blade 608 via a universal joint 635.

[0098] 7, the connecting portion 633B of the connecting member 633 is connected to the transmission member 640. Therefore, the connecting member 633 rotates together with the transmission member 640. That is, the connecting member 633 receives torque from the power generating device 631 and is rotatable around the central axis 31A of the motor 31 and therefore the power generating device 631 as the rotation center.

[0099] <Universal joint> As shown in Fig. 7, universal joint 635 is a ball joint. That is, universal joint 635 includes socket 635A and rod 635B. Socket 635A has a cylindrical outer shape. Main body 633A of connecting member 633 is fixed to one end face of socket 635A in the direction of its central axis. The end of socket 635A opposite to the side where connecting member 633 is fixed forms a spherical housing space.

[0100] The rod 635B is cylindrical overall. The head of the rod 635B is spherical. The head of the rod 635B is housed in the housing space of the socket 635A. The head of the rod 635B is freely rotatable within the housing space of the socket 635A. The angle between the rod 635B and the socket 635A can be freely changed. Although not shown, a flange protruding from the outer circumferential surface of the rod 635B is provided at the end of the rod 635B opposite the head. The flange is attached to the rear surface of the dozer blade 608 using an attachment means. Various attachment means can be used, such as bolting or welding. In this way, the universal joint 635 is located at the attachment point of the connecting member 633 to the dozer blade 608 and connects the connecting member 633 and the dozer blade 608.

[0101] <Driven sprocket> As shown in FIG. 6 , the driven sprocket 637 is located at the forefront of the traveling crawler 611. That is, the driven sprocket 637 is located at the end of the traveling crawler 611 opposite the drive sprocket 618 across the front-to-rear center of the traveling crawler 611. The driven sprocket 637 is annular. As shown in FIG. 7 , the central axis of the driven sprocket 637 substantially coincides with the central axis 31A of the power generator 631. That is, the driven sprocket 637 is arranged coaxially with the power generator 631. The reducer 35 is inserted through a central hole of the driven sprocket 637. A plurality of teeth are formed on the outer circumferential surface of the driven sprocket 637. The teeth are arranged at equal intervals in the circumferential direction around the central axis of the driven sprocket 637. The teeth of the driven sprocket 637 mesh with the grooves 611A of the traveling crawler 611.

[0102] The bearing 639 is located between the driven sprocket 637 and the reducer 35. The bearing 639 is cylindrical overall. The bearing 639 is, for example, a roller bearing. That is, the bearing 639 includes an inner ring, an outer ring, and multiple rolling elements. Both the inner ring and the outer ring are cylindrical. The outer diameter of the inner ring is smaller than the inner diameter of the outer ring. The central axes of both the inner ring and the outer ring substantially coincide with the central axis 31A of the power generating device 631. The rolling elements are, for example, cylindrical or spherical. The inner peripheral surface of the inner ring is fixed to the outer peripheral surface of the reducer 35. The outer peripheral surface of the outer ring is fixed to the inner peripheral surface of the driven sprocket 637. As a result, the bearing 639 supports the driven sprocket 637 rotatably relative to the reducer 35. Note that the bearing 639 is not shown in FIG. 6.

[0103] <Transmission components> The transmission member 640 will be described in detail. As shown in FIG. 7, the transmission member 640 includes a first member 641 and a second member 642. Both the first member 641 and the second member 642 are disk-shaped overall. The diameter of the first member 641 and the diameter of the second member 642 are the same. The central axis of the first member 641 approximately coincides with the central axis 31A of the power generating device 631. The central axis of the second member 642 also approximately coincides with the central axis 31A of the power generating device 631. The first member 641 and the second member 642 are aligned in a direction along the central axis 31A of the power generating device 631. In this embodiment, the first member 641 is adjacent to the reducer 35. The second member 642 is located on the opposite side of the first member 641 from the reducer 35.

[0104] 8, the first member 641 has a first mounting surface 641A that faces the reducer 35. The first mounting surface 641A is flat. The first mounting surface 641A is in surface contact with the end surface of the reducer 35. The first mounting surface 641A is fixed to the end surface of the reducer 35.

[0105] The surface of the first member 641 opposite the first mounting surface 641A is a first opposing surface 641B that faces the second member 642. The first opposing surface 641B forms a flat first surface. A recess 641C is formed in the first opposing surface 641B. The recess 641C is recessed from the first opposing surface 641B toward the reducer 35 in the Y direction. The recess 641C extends linearly along a first axis that is parallel to the first opposing surface 641B. The first axis extends in the longitudinal direction of the main body 633A of the connecting member 633. When the first member 641 is viewed in a plan view in the Y direction, the recess 641C passes through the center of the circle of the first member 641. When the first member 641 is viewed in a plan view in the Y direction, both ends of the recess 641C reach the outer edges of the first opposing surface 641B. In addition, in the direction along the first axis, both ends of the recess 641C are open toward the outside of the first member 641. The outer shape of the recess 641C is a rectangular parallelepiped.

[0106] As shown in FIG. 9 , the second member 642 has a second opposing surface 642A that faces the first opposing surface 641B of the first member 641. The second opposing surface 642A forms a flat second surface. A convex portion 642C protrudes from the second opposing surface 642A. The convex portion 642C extends linearly along the first axis. When the second member 642 is viewed in a plan view in the Y direction, the convex portion 642C is located opposite the concave portion 641C of the first member 641. When the second member 642 is viewed in a plan view in the Y direction, the convex portion 642C passes through the center of the circle of the second member 642. When the second member 642 is viewed in a plan view in the Y direction, both ends of the convex portion 642C reach the outer edge of the second opposing surface 642A. The outer shape of the convex portion 642C is a rectangular parallelepiped.

[0107] The dimensions of the rectangular parallelepiped of the protrusion 642C are basically the same as the dimensions of the rectangular parallelepiped of the recess 641C in the first member 641. Specifically, the protrusion length of the protrusion 642C from the second opposing surface 642A is slightly smaller than the depth of the recess 641C from the first opposing surface 641B. Furthermore, the dimension of the protrusion 642C in a direction perpendicular to both the first axis and the central axis of the second member 642 is slightly smaller than the dimension of the recess 641C in a direction perpendicular to both the first axis and the central axis of the first member 641. Based on this size relationship between the protrusion 642C and the recess 641C, the protrusion 642C is accommodated in the recess 641C. At the same time, the second opposing surface 642A is in surface contact with the first opposing surface 641B.

[0108] The surface of the second member 642 opposite to the second opposing surface 642A is a second mounting surface 642B that faces the connecting portion 633B of the connecting member 633. The second mounting surface 642B is flat. The second mounting surface 642B is in surface contact with the connecting portion 633B. The second mounting surface 642B is fixed to the connecting portion 633B.

[0109] Although not shown, the transmission member 640 has a structure such as a stopper for preventing the protrusion 642C from coming off the recess 641C. As a structure for preventing the protrusion 642C from coming off the recess 641C, for example, the outer circumferential surfaces of the first member 641 and the second member 642 may be covered with an annular cover. Furthermore, an elastic member such as a spring may be provided between such a cover and both end surfaces of the protrusion 642C in the direction along the first axis.

[0110] <Control configuration> As shown in FIG. 6 , the excavator 600 includes a control device 601. The control device 601 is mounted on, for example, the upper body 530. The control device 601 may include a processing circuit including one or more processors that execute various processes according to a computer program (software). The control device 601 may also include a processing circuit including one or more dedicated hardware circuits, such as an application-specific integrated circuit (ASIC), that executes at least some of the various processes, or a processing circuit including a combination of the processor and the dedicated hardware circuit. The processor includes a CPU and memory such as RAM and ROM. The memory stores program code or instructions configured to cause the CPU to execute processes. The memory, i.e., computer-readable medium, includes any available medium accessible by a general-purpose or dedicated computer. The memory includes electrically rewritable non-volatile memory. The control device 601 controls the motors 31 of the two power transmission mechanisms 630. The control device 601 also controls the motor of the output unit 617.

[0111] <Operation of the Second Embodiment> The control device 601 drives the motor of the output unit 617 in response to instructions from the occupant. When the motor of the output unit 617 is driven, the drive sprocket 618 rotates. At the same time, the drive sprocket 618 drives the traveling crawler 611 to rotate. As the traveling crawler 611 rotates, the excavator 600 travels forward or backward. As the traveling crawler 611 rotates, the multiple rollers 616 guide the traveling crawler 611 as it rotates. Furthermore, as the traveling crawler 611 rotates, the driven sprocket 637 rotates in accordance with the rotation of the traveling crawler 611.

[0112] In response to an instruction from the occupant, the control device 601 drives the motors 31 of the two power transmission mechanisms 630. When driving these motors 31, the control device 601 controls the motors 31 in either a synchronous mode or an individual mode in response to an instruction from the occupant.

[0113] In the synchronous mode, the control device 601 controls the two motors 31 in synchronization. That is, in the synchronous mode, the control device 601 rotates the output shafts 33 of the two motors 31 in the same rotation direction at the same rotation speed. When the control device 601 rotates the output shafts 33 of the two motors 31 in the synchronous mode, the left and right connecting members 633 rotate in the same direction around the central axis 31A of the power generating device 631. At the same time, the dozer blade 608 rotates around the central axis 31A of the power generating device 631. By controlling the rotation in the same direction, the dozer blade 608 rotates upward or downward as indicated by the arrow 630A. That is, the control device 601 raises and lowers the dozer blade 608.

[0114] In the individual mode, the control device 601 controls the two motors 31 individually. That is, in the individual mode, the control device 601 rotates one of the output shafts 33 of the two motors 31 while keeping the other stationary, rotates one and the other in the same rotation direction at different rotation speeds, or rotates one and the other in opposite directions. For example, the control device 601 rotates the left-side connecting member 633 downward as indicated by arrow 600M in FIG. 10, while rotating the right-side connecting member 633 upward as indicated by arrow 600N in FIG. 10. As a result, as indicated by the two-dot chain line in FIG. 10, the dozer blade 608 is tilted so that the right-side end is positioned higher than the left-side end.

[0115] <Effects of the second embodiment> (2-1) In the backhoe 600 of this embodiment, the power generating unit 631 is located inside the traveling crawler 611. This eliminates the need to provide mounting space for the power generating unit 631 in the upper body 530 and the lower body 605. This makes it possible to reduce the size of the upper body 530 and the lower body 605, and increase the space available in the upper body 530 and the lower body 605 for other uses.

[0116] Here, when transmitting the torque of the power generating unit 631 to the dozer blade 608, it is conceivable to connect the power generating unit 631 and the dozer blade 608 with a link mechanism. Then, it is conceivable to provide a connecting member 633 for rotatably supporting the dozer blade 608 with respect to the vehicle body 603, in addition to the link mechanism. However, when such an embodiment is adopted, it is necessary to mount not only the connecting member 633 but also the link mechanism on the excavator 600, and therefore the number of parts mounted on the excavator 600 increases by the amount of the link mechanism. In this regard, in the excavator 600 of this embodiment, the power generating unit 631 and the connecting member 633 are directly connected, so that the torque of the power generating unit 631 can be directly transmitted to the connecting member 633. In such an embodiment, the connecting member 633 can perform both the function of rotatably supporting the dozer blade 608 with respect to the vehicle body 603 and the function of transmitting the torque of the power generating unit 631 to the dozer blade 608, and therefore the link mechanism is not necessary in the excavator 600. Therefore, in the configuration of this embodiment, the number of parts mounted on the backhoe 600 can be reduced.

[0117] (2-2) The backhoe 600 of this embodiment includes two sets of power transmission mechanisms 630 and therefore two power generating units 631. Therefore, when raising and lowering the dozer blade 608, the torque output by each power generating unit 631 can be reduced. This contributes to the miniaturization of each power generating unit 631.

[0118] (2-3) In the excavator 600 of this embodiment, the connecting member 633 and the dozer blade 608 are connected via a universal joint 635. Furthermore, in the excavator 600 of this embodiment, the motors 31 of the left and right power transmission mechanisms 630 can be controlled in an individual mode. By operating the left and right motors 31 separately in this individual mode, the excavator 600 of this embodiment can use the dozer blade 608 by tilting it up and down.

[0119] (2-4) In the excavator 600 of this embodiment, when the power generating unit 631 is disposed inside the traveling crawler 611, the driven sprocket 637 is wound around the reducer 35 of the power generating unit 631 via a bearing 639. This makes it possible to dispose the power generating unit 631 at the forefront inside the traveling crawler 611. Furthermore, by disposing the power generating unit 631 at the forefront inside the traveling crawler 611, it is possible to shorten the distance between the dozer blade 608, which is positioned forward of the traveling crawler 611, and the power generating unit 631. This makes it possible to shorten the dimension of the connecting member 633 in the X direction.

[0120] (2-5) In the backhoe 600 of this embodiment, the transmission member 640 is composed of two members, a first member 641 and a second member 642. A convex portion 642C of the second member 642 fits into a concave portion 641C of the first member 641. This fitting relationship between the convex and concave portions makes the following possible. Here, as shown in FIG. 8, of the wall surfaces defining the concave portion 641C of the first member 641, two surfaces perpendicular to both the first shaft and the central axis of the first member 641 are referred to as first side surfaces 641CX. Furthermore, as shown in FIG. 9, of the outer surfaces constituting the convex portion 642C of the second member 642, two surfaces perpendicular to both the first shaft and the central axis of the second member 642 are referred to as second side surfaces 642CX. When the motor 31 in the power generating device 631 is driven, the first member 641 of the first member 641 and the second member 642 receives torque from the reducer 35 and rotates. When the first member 641 rotates, a first side surface 641CX of the recessed portion 641C of the first member 641 comes into contact with a second side surface 642CX of the protruding portion 642C of the second member 642. The first side surface 641CX then transmits the torque to the second side surface 642CX. That is, the transmission member 640 transmits the torque between the first member 641 and the second member 642 by the engagement of the recessed and protruding portions. The second member 642 then transmits the torque to the connecting member 633. In this way, the transmission member 640 can reliably transmit the torque output by the reducer 35 to the connecting member 633.

[0121] As described above, in the excavator 600 of this embodiment, the power generating unit 631 and the connecting member 633 are directly connected to each other, so that the torque of the power generating unit 631 is directly transmitted to the connecting member 633. In this case, while the effect of (2-1) can be obtained, there is the following trade-off. That is, when the power generating unit 631 and the connecting member 633 are directly connected to each other, when an external force acts on the dozer blade 608 from the forward direction, there is a risk that the load associated with this external force will be input from the connecting member 633 to the power generating unit 631. The power generating unit 631 of this embodiment has a function of releasing this load. Specifically, the transmission member 640 of the power generating unit 631 performs this function. This point will be explained below. As a premise, the load acting on the dozer blade 608 has a component in the longitudinal direction of the connecting member 633. That is, the load acts on the connecting member 633 and, in turn, on the second member 642 of the transmission member 640 connected to the connecting member 633 in the longitudinal direction of the connecting member 633. Meanwhile, the recessed portion 641C of the first member 641 and the protruding portion 642C of the second member 642 extend in the longitudinal direction of the first axis and, in turn, of the connecting member 633. Therefore, when the load acts on the second member 642 of the transmission member 640 via the connecting member 633, the protruding portion 642C of the second member 642 moves slightly in the direction along the first axis within the recessed portion 641C of the first member 641. This allows the load acting on the second member 642 from the connecting member 633 to be released. With this configuration of the present embodiment, it is possible to prevent an external force acting on the dozer blade 608 from reaching the reducer 35 and the motor 31. This contributes to preventing the power generating device 631 from becoming large, as described in (1-3) of the first embodiment, for example.

[0122] <Modification of the second embodiment> The second embodiment can be modified as follows: The first embodiment, the second embodiment, and the following modifications can be combined and implemented within the scope of technical compatibility.

[0123] It is not essential that the transmission member 640 be divided into two members, the first member 641 and the second member 642. For example, the transmission member 640 may be a cylindrical member in which the first member 641 and the second member 642 are integrated. It is sufficient that the transmission member 640 is able to transmit the torque from the reducer 35 to the connecting member 633.

[0124] It is not essential that the power generating device 631 include the reducer 35 and the transmission member 640. The power generating device 631 may include an electric motor 31. For example, the power generating device 631 may be configured with only the motor 31, and the motor 31 may be directly connected to the connecting member 633.

[0125] Among the components constituting the power generating device 631, the component through which the driven sprocket 637 is inserted is not limited to the reducer 35. It is sufficient that one or more components constituting the power generating device 631 are inserted through the driven sprocket 637.

[0126] A roller may be used instead of the driven sprocket 637 as a driven part for the traveling crawler 611, which is disposed on the outer periphery of the power generating device 631. In other words, a driven part that does not have teeth formed on its outer periphery may be used.

[0127] It is not essential to provide a driven part that follows the traveling crawler 611 on the outer periphery of the power generating device 631. Regardless of the presence or absence of a driven part, the traveling device 610 and the like may be configured appropriately so that the traveling crawler 611 can move smoothly around.

[0128] The position of the power generating unit 631 within the traveling crawler 611 is not limited to the example in the above embodiment. For example, the output unit 617 and the drive sprocket 618 may be disposed at the forefront of the traveling crawler 611, and the power generating unit 631 and the driven sprocket 637 may be disposed at the rearmost part of the traveling crawler 611. When adopting such an embodiment, for example, if the dozer blade 608 is disposed rearward of the traveling crawler 611, the distance in the X direction from the power generating unit 631 to the dozer blade 608 becomes shorter, as in the above embodiment. Therefore, the connecting member 633 connecting the power generating unit 631 and the dozer blade 608 can be shortened.

[0129] The universal joint 635 is not limited to the example of the above embodiment. The universal joint 635 may be any joint that can freely change the connection angle between the connecting member 633 and the dozer blade 608. The universal joint 635 is not essential. That is, the connecting member 633 and the dozer blade 608 may be directly connected.

[0130] When the universal joint 635 is eliminated, the use of the individual mode may be eliminated in the control device 601. In other words, it is not essential that the control device 601 be able to use the individual mode. Either one of the left or right power generating units 631 may be eliminated. When eliminating one of the left or right power generating units 631, the connecting member 633 on the side where the power generating unit 631 is eliminated may be rotatably connected to the front wall 623 of the crawler frame 620 on the side opposite to the connection point with the dozer blade 608 using, for example, a shaft-shaped member such as the first support shaft 21 of the first embodiment. In this case, the connecting member 633 on the side where the power generating unit 631 is eliminated rotates up and down around the shaft-shaped member as the center of rotation, following the elevation and lowering of the dozer blade 608. Note that eliminating either the left or right power generating units 631 is equivalent to eliminating either the left or right power transmission mechanisms 630. In other words, it is not necessary to provide a power transmission mechanism 630 corresponding to both of the two traveling crawlers 611.

[0131] The configuration of the connecting member 633 is not limited to the example of the above embodiment. For example, the connecting member 633 may be a rectangular plate. The connecting member 633 only needs to be connected to the power generating device 631 and to allow the dozer blade 608 to be attached to the side opposite to the point where it is connected to the power generating device 631.

[0132] The configuration of the crawler frame 620 is not limited to the example in the above embodiment. The crawler frame 620 may be configured to support the output unit 617, the rollers 616, and the power generating device 631.

[0133] It is not essential that the power generating device 631 be supported by the crawler frame 620. For example, the power generating device 631 may be supported by the lower body 605. As long as the power generating device 631 can be placed inside the traveling crawler 611, the configuration for supporting the power generating device 631 is not important.

[0134] The configuration of the dozer blade 608 is not limited to the example of the above embodiment. The dozer blade 608 may have any configuration that can achieve the required purpose, such as grading, digging, and stirring up earth and sand.

[0135] The construction machine to which the dozer blade drive mechanism 600A is applied is not limited to the example of the above embodiment. For example, the dozer blade drive mechanism 600A can also be applied to a bulldozer or a compact track loader.

[0136] In the above embodiments, if an object is made up of multiple objects, the multiple objects may be integrated, and conversely, if an object is made up of a single object, it may be divided into multiple objects. Regardless of whether the objects are integrated or not, it is sufficient that the object of the invention can be achieved.

[0137] Third Embodiment A third embodiment of the dozer blade drive mechanism will be described below with reference to Figures 11 and 12. Note that the drawings may show components enlarged to facilitate understanding. The dimensional ratios of the components may differ from the actual ones or from those in other drawings. In Figures 11 and 12, parts that are the same as or function substantially the same as those in Figures 1 to 10 are denoted by the same reference numerals as those in Figures 1 to 10. In the following description, parts that overlap with the first or second embodiment may be omitted or simplified as appropriate.

[0138] As shown in FIG. 11, an excavator 650, which is a construction machine, includes a vehicle body 653. The vehicle body 653 includes a lower body 660 and an upper body 530. The configuration of the upper body 530 is the same as that of the first embodiment. The configuration of the lower body 660 will be described later. The upper body 530 is located on the opposite side of the lower body 660 from the ground. In this embodiment, up, down, left, right, front, and rear are defined in the same way as in the first embodiment. The upper body 530 is rotatable left and right relative to the lower body 660 around an axis extending substantially in the Z direction.

[0139] As shown in FIG. 11, the backhoe 650 includes a work attachment 510 and a dozer blade 608. The configuration of the work attachment 510 is the same as that of the first embodiment. The configuration of the dozer blade 608 is the same as that of the second embodiment. As shown in FIGS. 11 and 12, the backhoe 650 includes a pair of traveling devices 550. The configuration of the traveling devices 550 is the same as that of the first embodiment. That is, the pair of traveling devices 550 include endless belt-like crawlers and an operating mechanism for moving the crawlers. The operating mechanism is included in a vehicle body 653 of the backhoe 650. Note that the upper body 530 and the work attachment 510 are not shown in FIG. 12.

[0140] <Dozer blade drive mechanism> The backhoe 650 is equipped with a dozer blade drive mechanism 651. In this embodiment, the lower body 660 is included as one element of the dozer blade drive mechanism 651. As shown in FIG. 12 , the lower body 660 is equipped with a main section 661, a support wall section 665, and a pair of extension wall sections 663. The main section 661 has an outer shape of, for example, a rectangular parallelepiped. The main section 661 houses various mechanisms required to operate the backhoe 650. Note that the main section 661 is not limited to a box shape, and may have any shape as long as it can be fitted with necessary parts, etc.

[0141] The support wall portion 665 protrudes forward from the front surface of the main portion 661. The support wall portion 665 is fixed to the main portion 661. The center of the main portion 661 in the Y direction is referred to as the base center 661C. The base center 661C is also the center between the left and right traveling devices 550 and, ultimately, the crawlers in the Y direction. In the Y direction, the support wall portion 665 is disposed so as to straddle the base center 661C. The outer shape of the support wall portion 665 is a rectangular parallelepiped. One side of the rectangular parallelepiped of the support wall portion 665 is aligned with the Y direction. The center of the support wall portion 665 in the Y direction is located at the base center 661C. The support wall portion 665 has an accommodation hole 665A. The accommodation hole 665A penetrates the support wall portion 665 in the Y direction. The support wall 665 constitutes a wall for mounting a power generating device 631, which will be described later.

[0142] The pair of extension wall portions 663 are located on the left and right sides of the body center 661C. The pair of extension wall portions 663 protrude forward from the front surface of the main portion 661. The pair of extension wall portions 663 are fixed to the main portion 661. One of the pair of extension wall portions 663 is located at the left end of the main portion 661. The other of the pair of extension wall portions 663 is located at the right end of the main portion 661. The extension wall portion 663 is plate-shaped. The main surface of the extension wall portion 663 faces the Y direction. As already explained, the main surface is the surface with the largest area among the outer surfaces of the plate-shaped member. Although not shown in the figure, the extension wall portion 663 has a support hole. The support hole penetrates the extension wall portion 663 in the Y direction.

[0143] As shown in Fig. 12, the dozer blade drive mechanism 651 includes two sets of power transmission mechanisms 670. The two sets of power transmission mechanisms 670 are provided corresponding to the left and right sides of the main body center 661C. The two sets of power transmission mechanisms 670 are configured symmetrically. Therefore, the following description will be given of the power transmission mechanism 670, taking as an example the one of the two sets of power transmission mechanisms 670 located on the left side of the main body center 661C.

[0144] The power transmission mechanism 670 is configured as a set of a power generating device 631 and a connecting member 633. The power generating device 631 includes a motor 31, a reducer 35, and a transmission member 640.

[0145] The motor 31 is located in the accommodation hole 665A of the support wall portion 665. More specifically, the motor 31 is located on the left side of the accommodation hole 665A with respect to the body center 661C. The motor 31 is a drive source for the power generating device 30. The motor 31 includes a housing 32 and an output shaft 33. The motor 31 is an electrically powered motor that operates in response to power supplied from a battery (not shown). The housing 32 is fixed to the inner surface of the accommodation hole 665A. Most of the output shaft 33 is located inside the housing 32. A portion of the output shaft 33 protrudes from the housing 32 toward the opposite side from the body center 661C. The output shaft 33 is cylindrical. A central axis 31A of the output shaft 33 extends in the Y direction. The output shaft 33 is rotatable relative to the housing 32. The output shaft 33 rotates about its own central axis 31A. The output shaft 33 is rotatable in both forward and reverse directions in response to the supply of power to the motor 31. Hereinafter, the central axis 31A of the output shaft 33 may be referred to as the central axis 31A of the motor 31.

[0146] The reducer 35 is adjacent to the motor 31 in the direction along the central axis 31A of the motor 31. The reducer 35 is located on the opposite side of the motor 31 across the body center 661C. A portion of the reducer 35 is located in the accommodating hole 665A of the support wall portion 665. The remaining portion of the reducer 35 is exposed to the outside of the support wall portion 665. The portion of the reducer 35 located inside the accommodating hole 665A is fixed to the inner surface of the accommodating hole 665A. The reducer 35 is cylindrical overall. The central axis of the reducer 35 substantially coincides with the central axis 31A of the motor 31. The reducer 35 is connected to the output shaft 33 of the motor 31. The torque of the output shaft 33 of the motor 31 is input to the reducer 35. The reducer 35 amplifies the torque of the output shaft 33 of the motor 31 at a predetermined ratio and outputs it. The reducer 35 may be, for example, an eccentric oscillating gear type or a planetary gear type. Any type of reducer may be used as the reducer 35 as long as it is configured to amplify and output the torque from the motor 31.

[0147] The transmission member 640 is adjacent to the reducer 35 in the direction along the central axis 31A of the motor 31. The transmission member 640 is located on the opposite side of the reducer 35 from the motor 31. The transmission member 640 is connected to the reducer 35. The configuration of the transmission member 640 is the same as that of the second embodiment. That is, the transmission member 640 includes a first member 641 and a second member 642. The torque output by the reducer 35 is input to the transmission member 640. The transmission member 640 rotates upon receiving the torque from the reducer 35. The rotation center axis of the transmission member 640 coincides with the central axis 31A of the motor 31. That is, the transmission member 640 outputs torque centered on the central axis 31A of the motor 31. As described above, the power generating device 30 uses the motor 31 as a drive source to generate torque centered on the central axis 31A of the motor 31. Hereinafter, the central axis 31A of the motor 31 may be referred to as the central axis 31A of the power generating device 631.

[0148] The connecting member 633 is adjacent to the transmission member 640 in the direction along the central axis 31A of the motor 31. Specifically, the connecting member 633 is located on the opposite side of the transmission member 640 from the reducer 35. The configuration of the connecting member 633 is the same as that of the second embodiment. That is, as shown in FIG. 11 , the connecting member 633 includes a rod-shaped main body 633A and a connecting portion 633B located at one longitudinal end of the main body 633A. As shown in FIG. 12 , the connecting portion 633B is located between the transmission member 640 and the extension wall portion 663. The connecting portion 633B is fixed to the second member 642 of the transmission member 640 by an attachment means. Various attachment means, such as bolting or welding, can be used. A support shaft 671 penetrates the connecting portion 633B. The support shaft 671 protrudes from a support hole in the extension wall portion 663. The support shaft 671 is fixed to the inner surface of the support hole. The support shaft 671 is cylindrical. The central axis of the support shaft 671 extends in the Y direction. The central axis of the support shaft 671 substantially coincides with the central axis 31A of the motor 31. The support shaft 671 and the connecting portion 633B are not fixed to each other and are capable of rotating relative to each other.

[0149] The main body 633A of the connecting member 633 extends linearly forward from the connecting portion 633B. The dozer blade 608 can be attached by an attachment means to the front end of the connecting member 633, i.e., the side of the connecting member 633 opposite to the point where the connecting member 633 is connected to the power generating device 631. Various attachment means can be used, such as bolt fastening or welding. In this embodiment, the rear surface of the dozer blade 608 is attached to the front end of the main body 633A of the connecting member 633. Although not shown in the drawings, similar to the second embodiment, the longitudinal direction of the main body 633A substantially coincides with the extension direction of the recessed portion 641C and the protruding portion 642C of the transmission member 640.

[0150] <Operation of the Third Embodiment> As described above, the connecting portion 633B of the connecting member 633 is connected to the transmission member 640. Therefore, when the transmission member 640 rotates in accordance with the rotation of the output shaft 33 of the motor 31, the connecting member 633 rotates together with the transmission member 640. That is, as shown by the arrow 650A in FIG. 11 , the connecting member 633 receives torque from the power generating device 631 and rotates upward or downward about the central axis 31A of the motor 31. At the same time, the dozer blade 608 rotates upward or downward about the central axis 31A of the motor 31. That is, the dozer blade 608 moves up and down.

[0151] <Effects of the third embodiment> As explained in (3-1) and (2-1), it is conceivable to mount a link mechanism in addition to the connecting member 633 on the excavator 650 to transmit the torque of the power generating device 631 to the dozer blade 608. However, in this case, the number of parts mounted on the excavator 650 increases. In this regard, in the excavator 650 of this embodiment, the power generating device 631 and the connecting member 633 are directly connected to each other, so that the torque of the power generating device 631 is directly transmitted to the connecting member 633. In this case, the connecting member 633 has both the function of rotatably supporting the dozer blade 608 with respect to the vehicle body 653 and the function of transmitting the torque of the power generating device 631 to the dozer blade 608, so that a link mechanism is not necessary. With the configuration of this embodiment, the number of parts mounted on the excavator 650 can be reduced.

[0152] In addition, the power generating device 631 of this embodiment employs a transmission member 640 composed of a first member 641 and a second member 642. Therefore, similar to the second embodiment (2-5), it is possible to prevent the external force acting on the dozer blade 608 from reaching the reducer 35 and the motor 31.

[0153] (3-2) In the backhoe 650 of this embodiment, the support wall 665 for supporting the power generating unit 631 straddles the main body center 661C. When the support wall 665 is provided in this position, unlike when the support wall 665 is provided in a position offset to the left or right of the main body center 661C, the weight of the power generating unit 631 is supported at approximately the center in the Y direction of the main part 661 of the lower body 660. Therefore, it is possible to prevent the weight acting from the main part 661 on the pair of traveling devices 550 from being offset to the left or right of the backhoe 650. This stabilizes the balance of the backhoe 650 when traveling, for example.

[0154] (3-3) The backhoe 650 of this embodiment includes two sets of power transmission mechanisms 670 and therefore two power generating units 631. Therefore, when raising and lowering the dozer blade 608, the torque output by each power generating unit 631 can be reduced. This contributes to the miniaturization of each power generating unit 631.

[0155] <Modification of the third embodiment> The third embodiment can be modified as follows: Furthermore, the first to third embodiments and the following modifications can be combined with each other within the scope of technical compatibility.

[0156] The shape of the support wall portion 665 is not limited to the example in the above embodiment. The support wall portion 665 may be configured to be able to support the power generating device 631. The configuration for supporting the power generating device 631 by the support wall portion 665 is not limited to the example of the above embodiment. For example, the support wall portion 665 may be provided with an uneven structure for supporting the power generating device 631, or the power generating device 631 may be fixed to the outer surface of the support wall portion 665 with bolts or the like.

[0157] The arrangement of the support wall portion 665 is not limited to the example in the above embodiment. The support wall portion 665 may be biased to either the left or right side of the base center 661C. Furthermore, the support wall portion 665 does not have to straddle the base center 661C.

[0158] The portion to which the power generating device 631 is attached may not be a wall portion that falls under the category of the support wall portion 665. In other words, the support wall portion 665 is not essential. The power generating device 631 only needs to be attached to the lower body 660. Furthermore, the power generating device 631 only needs to be attached somewhere on the body 653 of the backhoe 650.

[0159] The shape of the extension wall portion 663 is not limited to the example in the above embodiment. The extension wall portion 663 may be configured to be able to support the support shaft 671. The extension wall portion 663 may be eliminated.

[0160] Either one of the left and right power generating devices 631 may be eliminated. When eliminating either one of the left and right power generating devices 631, the connecting member 633 on the side where the power generating device 631 is eliminated may be rotatably supported by the support shaft 671 on the side opposite to the connection point with the dozer blade 608, for example. Eliminating either one of the left and right power generating devices 631 corresponds to eliminating either one of the left and right power transmission mechanisms 670.

[0161] The configuration of the connecting member 633 is not limited to the example of the above embodiment. The connecting member 633 may be connected to the power generating device 631 and may have a dozer blade 608 attached to the side opposite to the connection point with the power generating device 631.

[0162] It is not essential that the transmission member 640 be divided into two members, the first member 641 and the second member 642. For example, the transmission member 640 may be a cylindrical member in which the first member 641 and the second member 642 are integrated. It is sufficient that the transmission member 640 is able to transmit the torque from the reducer 35 to the connecting member 633.

[0163] It is not essential that the power generating device 631 include the reducer 35 and the transmission member 640. For example, the power generating device 631 may be configured with only the motor 31, and the motor 31 may be directly connected to the connecting member 633. The power generating device 631 may simply include an electric motor 31.

[0164] The configuration of the dozer blade 608 is not limited to the example of the above embodiment. The dozer blade 608 may have any configuration that can achieve the required purpose, such as grading, digging, and stirring up earth and sand.

[0165] The construction machine to which the dozer blade drive mechanism 651 is applied is not limited to the example of the above embodiment. For example, the dozer blade drive mechanism 651 can also be applied to a bulldozer or a compact track loader.

[0166] In the above embodiments, if an object is made up of multiple objects, the multiple objects may be integrated, and conversely, if an object is made up of a single object, it may be divided into multiple objects. Regardless of whether the objects are integrated or not, it is sufficient that the object of the invention can be achieved.

[0167] <Fourth embodiment> A fourth embodiment of the dozer blade drive mechanism will be described below with reference to Figs. 13 to 17. Note that the drawings may show components enlarged to facilitate understanding. The dimensional ratios of the components may differ from the actual ones or from those in other drawings. In Figs. 13 to 17, parts that are the same as or function substantially the same as those in Figs. 1 to 12 are denoted by the same reference numerals as in Figs. 1 to 12. In the following description, parts that overlap with the first to third embodiments may be omitted or simplified as appropriate.

[0168] As shown in FIG. 13, an excavator 700, which is a construction machine, includes a vehicle body 703. The vehicle body 703 includes a lower body 705 and an upper body 710. The configuration of the lower body 705 is substantially the same as that of the main housing part 410 of the first embodiment. The configuration of the upper body 710 will be described later. The upper body 710 is located on the opposite side of the lower body 705 from the ground. In this embodiment, up, down, left, right, front, and rear are defined in the same way as in the first embodiment.

[0169] The excavator 700 is equipped with a slewing mechanism 707. The slewing mechanism 707 rotatably connects the upper body 710 to the lower body 705. Although not shown, the slewing mechanism 707 includes an annular inner ring, an annular outer ring, multiple rolling elements, and a slewing drive unit. The outer diameter of the inner ring is smaller than the inner diameter of the outer ring. The central axis of the inner ring approximately coincides with the central axis of the outer ring. The central axes of both the inner ring and the outer ring extend approximately in the Z direction. The multiple rolling elements are, for example, balls. The multiple rolling elements are located between the inner ring and the outer ring. The multiple rolling elements support the inner ring and the outer ring so that they can rotate relative to each other. As a result, the outer ring can rotate around its own central axis relative to the inner ring. The inner ring is fixed to the lower body 705. The outer ring is fixed to the upper body 710. That is, the upper body 710 is rotatable relative to the lower body 705 around an axis extending approximately in the Z direction. The slewing drive unit includes a motor and a reducer that decelerates and outputs the rotation of the motor. The motor is rotatable in both forward and reverse directions. As the motor is rotatable in both forward and reverse directions, the slewing drive unit is able to output torque in both forward and reverse directions. The torque output by the slewing drive unit drives the rotation of the outer wheel relative to the inner wheel. At the same time, the upper body 710 rotates left and right relative to the lower body 705.

[0170] The upper body 710 will be described in detail. As shown in FIG. 13, the upper body 710 includes a storage section 711, a riding section 712, and an extension section 713. The outer shape of the storage section 711 is a rectangular parallelepiped. The interior of the storage section 711 is hollow. Hereinafter, the interior of the storage section 711 will be referred to as a storage chamber 711A. The lower surface of the storage section 711 faces the lower body 705. The lower surface of the storage section 711 is fixed to the outer ring of the turning mechanism 707.

[0171] The riding section 712 is located above the storage section 711. The riding section 712 includes a seat for the operator, etc. The extension section 713 protrudes forward from the front surface of the storage section 711. The extension section 713 is fixed to the storage section 711. As shown in FIG. 14, the extension section 713 is located approximately in the center of the storage section 711 in the Y direction. Note that the riding section 712 is not shown in FIGS. 14, 16, and 17.

[0172] 13 and 14, the backhoe 700 includes a pair of traveling devices 550 and a dozer blade 608. The configuration of the traveling devices 550 is the same as that in the first embodiment. The configuration of the dozer blade 608 is the same as that in the second embodiment.

[0173] As shown in Figures 13 and 14, the excavator 700 is equipped with a work attachment 510. The configuration of the work attachment 510 is the same as that of the first embodiment. That is, the work attachment 510 is equipped with a columnar boom 515, a columnar work arm 513, and a box-shaped bucket 511. The boom 515 is connected to an extension 713 of the upper body 710. The bucket 511 is capable of digging up earth and sand.

[0174] <Dozer blade drive mechanism> The excavator 700 includes a dozer blade driving mechanism 701. As shown in FIGS.

[0175] As shown in FIG. 15, most of the power generating device 720 is located in the accommodation chamber 711A. The power generating device 720 includes a motor 722 and a pair of reducers 724. As shown in FIG. 14, the motor 722 is located in a front portion of the accommodation chamber 711A. The motor 722 is also located approximately in the center of the accommodation chamber 711A in the Y direction. The motor 722 is a drive source for the power generating device 720. The motor 722 is an electrically driven motor that operates in response to power supplied from a battery (not shown). As shown in FIG. 15, the motor 722 includes a housing 722A, an output shaft 722B, and a bevel gear 722C. The housing 722A is fixed to the wall surface of the accommodation chamber 711A. The output shaft 722B is cylindrical. The central axis of the output shaft 722B extends approximately in the Z direction. A portion of the output shaft 722B protrudes downward from the housing 722A. The output shaft 722B is rotatable relative to the housing 722A. The output shaft 722B rotates around its own central axis. The output shaft 722B is rotatable in both forward and reverse directions depending on the power supply to the motor 722. The bevel gear 722C is attached to the tip of the output shaft 722B that protrudes from the housing 722A. The bevel gear 722C has a truncated cone shape. The central axis of the bevel gear 722C approximately coincides with the central axis of the output shaft 722B. The diameter of the bevel gear 722C decreases downward. A plurality of teeth are formed on the outer circumferential surface of the bevel gear 722C.

[0176] The pair of reducers 724 are located on both the left and right sides of the motor 722. The pair of reducers 724 are located below the motor 722. The pair of reducers 724 are configured symmetrically. Therefore, in the following, the reducer 724 located on the left side of the motor 722 will be described as an example.

[0177] The reducer 724 includes a bevel gear 724D, an input shaft 724B, a main body 724A, and an output shaft 724C. The input shaft 724B is cylindrical. A central axis 724V of the input shaft 724B extends in the Y direction. The bevel gear 724D is attached to the input shaft 724B. The bevel gear 724D is frustoconical. The central axis 724V of the bevel gear 724D approximately coincides with the central axis 724V of the input shaft 724B. In this embodiment, parts whose axes approximately coincide with the input shaft 724B are designated by the unified reference symbol 724V. The diameter of the bevel gear 724D increases as it moves away from the motor 722 in the Y direction. A plurality of teeth are formed on the outer circumferential surface of the bevel gear 724D. The teeth of the bevel gear 724D mesh with the teeth of the bevel gear 722C of the motor 722. For convenience, the bevel gear 724D is depicted in FIG.

[0178] The main body 724A is connected to the input shaft 724B. The torque of the motor 722 is input to the main body 724A via the input shaft 724B. The main body 724A amplifies the torque of the motor 722 at a predetermined ratio and outputs it to its own output shaft 724C. The main body 724A may be, for example, an eccentric oscillating gear type or a planetary gear type. Any type of main body 724A may be used as long as it is configured to amplify and output the torque from the motor 722.

[0179] The output shaft 724C is cylindrical. A central axis 724V of the output shaft 724C substantially coincides with a central axis 724V of the input shaft 724B. A portion of the output shaft 724C protrudes to the outside of the accommodation chamber 711A.

[0180] The power generating device 720 is configured as described above. In the power generating device 720, when the output shaft 722B of the motor 722 rotates, the torque of the motor 722 is input to the reducer 724 through meshing between the bevel gear 722C of the motor 722 and the bevel gear 724D of the reducer 724. The reducer 724 generates torque centered on the central axis 724V of the output shaft 724C of the reducer 724 in accordance with the rotation of the output shaft 722B of the motor 722. In this embodiment, the central axis 724V of the output shaft 724C of the reducer 724 is the central axis of rotation of the power generating device 720. As described above, the power generating device 720 is accommodated in the accommodation chamber 711A of the accommodation unit 711. That is, the power generating device 720 is attached to the upper body 710.

[0181] 14, a pair of connecting members 715 are located on both the left and right sides of upper body 710. The pair of connecting members 715 are configured symmetrically. Therefore, the following description will be given of the connecting member 715 on the left side of the pair of connecting members 715 as an example.

[0182] As shown in FIG. 13, when the connecting member 715 is viewed from above in the Y direction, the connecting member 715 is L-shaped. That is, the connecting member 715 includes a first portion 715A corresponding to the vertical side of the L shape and a second portion 715B corresponding to the horizontal side of the L shape. The first portion 715A is elongated in the front-to-rear direction. The second portion 715B extends downward from the front end of the first portion 715A. The second portion 715B is approximately perpendicular to the first portion 715A. The dimensions of the second portion 715B are, for example, approximately half the dimensions of the first portion 715A.

[0183] 14, an output shaft 724C of the reducer 724 penetrates the rear end of the first portion 715A. The rear end of the first portion 715A and the output shaft 724C of the reducer 724 are fixed to each other. In other words, the first portion 715A is connected to the power generating device 720. The first portion 715A receives torque from the reducer 724 and rotates integrally with the output shaft 724C of the reducer 724.

[0184] 13, the dozer blade 608 can be attached to the end of the second portion 715B opposite to the end connected to the first portion 715A using an attachment means. That is, the dozer blade 608 can be attached to the end of the connecting member 715 opposite to the connection point with the power generating device 720. Various attachment means can be used, such as bolt fastening or welding. In this embodiment, an upper portion of the rear surface of the dozer blade 608 is attached to the second portion 715B.

[0185] As described above, the first portion 715A of the connecting member 715 is connected to the output shaft 724C of the reducer 724. Therefore, the central axis 724V of the output shaft 724C of the reducer 724 can be said to be the connecting point of the connecting member 715 with the power generating unit 720. Now, due to the positional relationship between the connecting member 715 and the dozer blade 608 described above, the dozer blade 608 is located forward of the central axis 724V of the output shaft 724C of the reducer 724. Meanwhile, the bucket 511 located at the tip of the work attachment 510 is also located forward as viewed from the central axis 724V of the output shaft 724C of the reducer 724. In other words, the dozer blade 608 and the bucket 511 are located on the same side as viewed from the central axis 724V of the output shaft 724C of the reducer 724. This positional relationship between the dozer blade 608 and the bucket 511 is referred to as a first relationship. Here, when the excavator 700 is viewed in the Y direction, that is, when the excavator 700 is viewed in a direction parallel to the central axis 724V of the output shaft 724C of the reducer 724, the direction in which the dozer blade 608 is located as viewed from the central axis 724V of the output shaft 724C of the reducer 724 is referred to as the first direction. Since the above first relationship is satisfied, the bucket 511 is also located on the first direction side as viewed from the central axis 724V of the output shaft 724C of the reducer 724.

[0186] <Operation of the Fourth Embodiment> As described above, the first portion 715A of the connecting member 715 is connected to the output shaft 724C of the reducer 724. Therefore, when the output shaft 724C of the reducer 724 rotates in accordance with the rotation of the output shaft 722B of the motor 722, the connecting member 715 rotates together with the output shaft 724C. That is, as shown by the arrow 700S in FIG. 13 , the connecting member 715 receives torque from the power generating device 720 and rotates upward or downward about the central axis 724V of the output shaft 724C of the reducer 724 as the rotation center. At the same time, the dozer blade 608 rotates upward or downward about the output shaft 724C of the reducer 724. That is, the dozer blade 608 moves up and down.

[0187] In this embodiment, the dozer blade 608 can be raised and lowered as described above, and can also pivot left and right together with the upper body 710. That is, in this embodiment, the connecting member 715, and therefore the dozer blade 608, are attached to the upper body 710. Therefore, for example, as shown in FIG. 16 , when the upper body 710 pivots approximately 30 degrees to the right relative to the lower body 705, the dozer blade 608 pivots approximately 30 degrees to the right together with the upper body 710. Furthermore, for example, as shown in FIG. 17 , when the upper body 710 pivots approximately 90 degrees to the right relative to the lower body 705, the dozer blade 608 pivots approximately 90 degrees to the right together with the upper body 710. Note that, although the case where the upper body 710 is pivoted to the right relative to the lower body 705 has been described as an example here, the dozer blade 608 also pivots together with the upper body 710 when the upper body 710 is pivoted to the left relative to the lower body 705.

[0188] <Effects of the Fourth Embodiment> (4-1) In the excavator 700 of this embodiment, the power generating unit 720, the connecting member 715, and the dozer blade 608 are attached to the upper body 710. Therefore, as described in the operation of the above embodiment, when the upper body 710 is rotated, the dozer blade 608 rotates together with the upper body 710. This makes it possible to do the following, for example. Now, as shown in FIG. 16 , assume that the dozer blade 608 is rotated approximately 30 degrees to the right with respect to the X direction. In this state, when the excavator 700 is driven forward, the operator can use the dozer blade 608 with the dozer blade 608 tilted with respect to the traveling direction of the excavator 700. This mode of use is not limited to excavating earth and sand, and is also effective for, for example, clearing snow.

[0189] (4-2) Suppose the dozer blade 608 is attached to the lower body 705. In this case, when the upper body 710 is rotated, the work attachment 510 and the dozer blade 608 may be positioned on opposite sides, i.e., front and rear. If the bucket 511 is used to excavate while the dozer blade 608 supports the ground in this state, the distance from the dozer blade 608 to the bucket 511 is long, which may cause the excavator 700 to lean forward and become unstable in its supporting state. In this regard, in the excavator 700 of this embodiment, when the upper body 710 is rotated, the bucket 511 and the dozer blade 608 are always positioned on the same side of the upper body 710. Therefore, when the dozer blade 608 supports the ground, the distance between the dozer blade 608 and the bucket 511 is short. Therefore, the supporting state of the excavator 700 is stable when excavating while the dozer blade 608 supports the ground.

[0190] (4-3) In the backhoe 700 of this embodiment, the connecting member 715 and the reducer 724 are directly connected to each other. Therefore, when an external force acts on the dozer blade 608 from the front side, the load associated with this external force can be input to the reducer 724 via the connecting member 715. Here, in the power generating device 720 of this embodiment, the central axis line of the output shaft 722B of the motor 722 and the central axis line 724V of the output shaft 724C of the reducer 724 are perpendicular to each other. Therefore, it is possible to prevent the load acting on the reducer 724 from reaching the motor 722.

[0191] <Modification of the Fourth Embodiment> The fourth embodiment can be modified as follows: The first to fourth embodiments and the following modifications can be combined with each other within the scope of technical compatibility.

[0192] The connecting member 715 and the reducer 724 may be connected via the transmission member 640 described in the second embodiment. The orientation of the motor 722 when it is disposed in the accommodation chamber 711A is not limited to the example of the above embodiment. For example, the motor 722 may be disposed so that its output shaft 722B extends in the Y direction. In this case, for example, a double-shaft motor in which the output shaft 722B protrudes on both sides of the housing 722A in the Y direction may be used. In this case, when the motor 722 is disposed so that the output shaft 722B extends in the Y direction, the bevel gear 722C of the motor 722 and the bevel gear 724D of the reducer 724 can be eliminated, and the output shaft 722B of the motor 722 and the input shaft 724B of the reducer 724 can be directly connected.

[0193] One of the pair of reducers 724 may be eliminated. At the same time, the torque of the power generating device 720 may be transmitted to only one of the pair of connecting members 715. In this case, the connecting member 715 located on the side where the reducer 724 is eliminated may be rotatably connected to the upper body 710 on the side opposite to the connection point with the dozer blade 608 using, for example, a shaft-shaped member such as the first support shaft 21 of the first embodiment. In this case, the connecting member 715 located on the side where the reducer 724 is eliminated rotates up and down around the shaft-shaped member as the center of rotation, following the elevation and lowering of the dozer blade 608.

[0194] As in the excavator 700A shown in FIG. 18, a dozer blade drive mechanism 701A may be provided with two power generating units 720A, each of which is a set of a motor 722 and a reducer 724. Torque may be transmitted separately from each power generating unit 720A to the left and right connecting members 715. Furthermore, the first dozer blade 608A attached to the left-hand connecting member 715 and the second dozer blade 608B attached to the right-hand connecting member 715 may be separate units. For example, the first dozer blade 608A and the second dozer blade 608B are obtained by splitting the dozer blade 608 of the above embodiment in half along the Y direction. With this configuration, a control device 700M that controls the motors 722 of the two power generating units 720A may be configured to individually control the motors 722 of the two power generating units 720A. 18, similar to Fig. 14, the riding section 712 is omitted from the illustration. In Fig. 18, parts that are the same as or have substantially the same functions as those in Figs. 1 to 17 are denoted by the same reference numerals as those in Figs. 1 to 17.

[0195] When the excavator 700 is viewed in a direction parallel to the central axis of rotation of the power generating unit 720, it is not essential that the bucket 511 be located on the side of the connecting member 715 where the dozer blade 608 is located, as viewed from the point where the connecting member 715 is connected to the power generating unit 720. For example, the dozer blade 608 and the bucket 511 may be located on opposite sides of the upper body 710 in the X direction. It is sufficient that the power generating unit 720, the connecting member 715, and therefore the dozer blade 608 are attached to the upper body 710. It is also sufficient that the dozer blade 608 can rotate together with the upper body 710 relative to the lower body 705.

[0196] The configuration of the connecting member 715 is not limited to the example of the above embodiment. The connecting member 715 may be connected to the power generating unit 720 and may have a dozer blade 608 attached to the side opposite to the connection point with the power generating unit 720.

[0197] It is not essential that the power generating device 720 includes the reducer 724. For example, the power generating device 720 may be configured with only the motor 722, and the motor 722 may be directly connected to the connecting member 715. When the power generating device 720 is configured with only the motor 722, the central axis of the output shaft 722B of the motor 722 becomes the central axis of rotation of the power generating device 720. It is sufficient that the power generating device 720 includes the electric motor 722.

[0198] The configuration of the dozer blade 608 is not limited to the example of the above embodiment. The dozer blade 608 may have any configuration that can achieve the required purpose, such as grading, digging, and stirring up earth and sand.

[0199] The construction machine to which the dozer blade drive mechanism 701 is applied is not limited to the example of the above embodiment. For example, the dozer blade drive mechanism 701 can also be applied to a bulldozer or a compact track loader.

[0200] In the above embodiments, if an object is made up of multiple objects, the multiple objects may be integrated, and conversely, if an object is made up of a single object, it may be divided into multiple objects. Regardless of whether the objects are integrated or not, it is sufficient that the object of the invention can be achieved.

[0201] Fifth Embodiment A fifth embodiment of the dozer blade drive mechanism will be described below with reference to Figures 19 to 24. Note that the drawings may show components enlarged to facilitate understanding. The dimensional ratios of the components may differ from the actual ones or from those in other drawings. In Figures 19 to 24, parts that are the same as or function substantially the same as those in Figures 1 to 18 are given the same reference numerals as in Figures 1 to 18. In the following description, parts that overlap with the first to fourth embodiments may be omitted or simplified as appropriate.

[0202] As shown in FIG. 19, a backhoe 800, which is a construction machine, includes a vehicle body 803. The vehicle body 803 further includes an upper body 530 and a lower body 810. The configuration of the upper body 530 is the same as that of the first embodiment. The configuration of the lower body 810 will be described later. The upper body 530 is located on the opposite side of the lower body 810 from the ground. In this embodiment, up, down, left, right, front, and rear are defined in the same way as in the first embodiment. The upper body 530 is rotatable left and right relative to the lower body 810 around an axis extending substantially in the Z direction.

[0203] The lower body 810 will now be described in detail. As shown in Figures 19 and 20, the lower body 810 includes a main section 811 and a pair of extension wall sections 812. The main section 811 has an outer shape of, for example, a rectangular parallelepiped. The main section 811 houses various mechanisms required to operate the backhoe 800. Note that the main section 811 is not limited to a box shape, and may have any shape as long as it can accommodate required parts and the like.

[0204] The pair of extension wall portions 812 are located on the front side of the main portion 811. The pair of extension wall portions 812 are fixed to the main portion 811. As shown in FIG. 20, the pair of extension wall portions 812 are located on the left and right sides of the center of the main portion 811 in the Y direction. The extension wall portions 812 are plate-shaped. The main surface of the extension wall portion 812 faces the Y direction. As already explained, the main surface is the surface with the largest area among the outer surfaces of a plate-shaped member. The extension wall portion 812 has a support hole 812A. The support hole 812A penetrates the extension wall portion 812 in the Y direction. The central axes of the pair of support holes 812A are approximately aligned with each other. Note that the support hole 812A is exaggerated in FIG. 20.

[0205] As shown in Figures 19 and 20, the backhoe 800 is equipped with a pair of traveling devices 550, a work attachment 510, and a dozer blade 608. The configurations of the traveling devices 550 and the work attachment 510 are the same as those in the first embodiment. The configuration of the dozer blade 608 is the same as that in the second embodiment. Note that the upper body 530 and the work attachment 510 are not shown in Figure 20.

[0206] <Dozer blade drive mechanism> As shown in Fig. 20, the excavator 800 includes a dozer blade drive mechanism 801. The dozer blade drive mechanism 801 includes a pair of connecting members 815. The pair of connecting members 815 are located on both the left and right sides of the lower body 810. The pair of connecting members 815 are configured symmetrically. Therefore, the following will describe in detail only one of the pair of connecting members 815.

[0207] The connecting member 815 is elongated in the front-to-rear direction. A support shaft 817 penetrates the rear end of the connecting member 815. The support shaft 817 is fixed to the main section 811 of the lower body 810. In other words, the connecting member 815 is connected to the main section 811 via the support shaft 817. The support shaft 817 is cylindrical. A central axis 817A of the support shaft 817 extends substantially in the Y direction. As shown by arrow 817B in FIG. 19 , the connecting member 815 is rotatable up and down relative to the main section 811 around the central axis 817A of the support shaft 817. In other words, the central axis 817A of the support shaft 817 is the central axis of rotation of the connecting member 815. The connecting member 815 extends linearly forward from the support shaft 817. The dozer blade 608 can be attached to the front end of the connecting member 815, i.e., the side of the connecting member 815 opposite to the connection point with the main section 811 of the lower body 810, using an attachment means. Various attachment means can be used, such as bolt fastening or welding. In this embodiment, the rear surface of the dozer blade 608 is attached to the front end of the connecting member 815. Note that in FIG. 19, the connecting member 815 is shown partially cut away to make it easier to understand the positional relationship of each component. Also, in FIGS. 21 to 24, the dozer blade 608 is shown in a simplified form.

[0208] <Case> As shown in Fig. 19, the dozer blade drive mechanism 801 includes a case 825. The case 825 is located forward of the main portion 811 of the lower body 810. In the Z direction, the case 825 is located downward of the upper body 530. As shown in Fig. 20, the case 825 is located between the pair of extension wall portions 812 in the Y direction.

[0209] The case 825 includes a case main body 826 and a pair of pins 827. The outer shape of the case main body 826 is a rectangular parallelepiped. The interior of the case main body 826 is hollow. Two of the multiple side surfaces of the case main body 826 form lateral surfaces facing the Y direction. The pair of pins 827 protrude in the Y direction from each of the two lateral surfaces. The pair of pins 827 are provided symmetrically. The pins 827 are cylindrical. The central axis of the pin 827 extends in the Y direction. The pin 827 is inserted into the support hole 812A of the extension wall portion 812. The pin 827 is rotatably supported by the support hole 812A. As described above, the rotation central axis of the connecting member 815 extends in the Y direction. In other words, the central axis of the pin 827 is parallel to the rotation central axis of the connecting member 815. Due to this arrangement, the case 825 is rotatable about a central axis parallel to the central axis of rotation of the connecting member 815 .

[0210] <Power Generation Device> 20 , the dozer blade driving mechanism 801 includes a power generating device 830. The power generating device 830 is housed inside a case main body 826. The power generating device 830 includes a motor 831 and a reducer 840. The motor 831 is a drive source of the power generating device 830.

[0211] As shown in FIG. 21 , the motor 831 includes a housing 832, an output shaft 833, and a bevel gear 834. The motor 831 is an electrically driven motor that operates in response to power supplied from a battery (not shown). The housing 832 is fixed inside the case main body 826. The output shaft 833 protrudes from inside the housing 832 to the outside. Specifically, the output shaft 833 protrudes forward relative to the housing 832. The output shaft 833 is cylindrical. The output shaft 833 is rotatable relative to the housing 832. The output shaft 833 rotates about its own central axis. The central axis of the output shaft 833 extends substantially in the X direction. The output shaft 833 is rotatable in both forward and reverse directions in response to power supplied to the motor 831. The bevel gear 834 is attached to a portion of the output shaft 833 that protrudes from the housing 832. The outer shape of the bevel gear 834 is a truncated cone. The output shaft 833 is fixed to a central hole of the bevel gear 834. The central axis of the bevel gear 834 approximately coincides with the central axis of the output shaft 833. The diameter of the outer circumferential surface of the bevel gear 834 decreases toward the front. A plurality of teeth are formed on the outer circumferential surface of the bevel gear 834.

[0212] The reducer 840 includes an input member 842, a bevel gear 843, a reducer body 841, and an output member 844. The input member 842 is cylindrical. A central axis 840C of the input member 842 extends substantially in the Z direction. An upper end face of the input member 842 is located slightly below the output shaft 833 of the motor 831. The input member 842 is connected to the reducer body 841 in a state where it can rotate about its own central axis 840C.

[0213] The bevel gear 843 is attached to the input member 842. The outer shape of the bevel gear 843 is a truncated cone. The input member 842 is fixed to a central hole of the bevel gear 843. The central axis 840C of the bevel gear 843 approximately coincides with the central axis 840C of the input member 842. In this embodiment, parts that approximately coincide with the central axis 840C of the input member 842 are designated by the unified reference symbol 840C. The diameter of the bevel gear 843 decreases toward the upper side. A plurality of teeth are formed on the outer peripheral surface of the bevel gear 843. The teeth of the bevel gear 843 mesh with the teeth of the bevel gear 834 of the motor 831. For convenience, in FIG. 21 , the bevel gear 843 is depicted at a position separated from the bevel gear 834 of the motor 831.

[0214] The reducer body 841 is located below the input member 842. The reducer body 841 is fixed inside the case body 826. The reducer body 841 is cylindrical. A central axis 840C of the reducer body 841 approximately coincides with a central axis 840C of the input member 842. The inner diameter of the reducer body 841 approximately coincides with the inner diameter of the input member 842. For example, the outer diameter of the reducer body 841 is larger than the outer diameter of the input member 842. An upper end face of the reducer body 841 is connected to a lower end face of the input member 842. The torque of the motor 831 is input to the reducer body 841 via the input member 842. The reducer body 841 amplifies the torque of the motor 831 at a predetermined ratio and outputs the amplified torque to the output member 844. In other words, the reducer body 841 reduces the rotation speed of the output shaft 833 of the motor 831 and outputs the reduced rotation speed to the output member 844. The reducer body 841 may be, for example, an eccentric oscillating gear type or a planetary gear type. Any type of reducer body 841 may be used as long as it is configured to amplify the torque from the motor 831 and output it.

[0215] The output member 844 is located below the reducer body 841. The output member 844 is cylindrical. A central axis 840C of the output member 844 substantially coincides with the central axis 840C of the reducer body 841. The inner diameter of the output member 844 substantially coincides with the inner diameter of the reducer body 841. For example, the outer diameter of the output member 844 substantially coincides with the outer diameter of the input member 842. An upper end face of the output member 844 is connected to a lower end face of the reducer body 841. The output member 844 receives torque from the reducer body 841 and is rotatable about its own central axis 840C. The output member 844 outputs the torque from the reducer body 841 to a nut 851 (described later). In this manner, the power generating device 830 generates torque centered on the central axis 840C of the reducer 840 in response to rotation of the output shaft 833 of the motor 831. In this embodiment, the central axis 840C of the reducer 840 is the central axis of rotation of the power generating device 830.

[0216] Here, as described above, case main body 826 is connected to extension wall portion 812 so as to be rotatable about a central axis parallel to the central axis of rotation of connecting member 815. Therefore, power generating device 830 housed in this case main body 826 is also connected to extension wall portion 812 in a state where it can be rotatable about a central axis parallel to the central axis of rotation of connecting member 815.

[0217] <Conversion mechanism> 21, the dozer blade driving mechanism 801 includes a conversion mechanism 850. The conversion mechanism 850 includes a nut 851, a screw shaft 855, and a plurality of balls 858.

[0218] The nut 851 includes a nut body 852 and a connecting portion 853. The nut body 852 is cylindrical. A central axis 840C of the nut body 852 substantially coincides with the central axis 840C of the reducer 840. The outer diameter of the nut body 852 substantially coincides with the inner diameter of the reducer body 841. The nut body 852 is inserted through the input member 842, the reducer body 841, and the output member 844 of the reducer 840. There is a gap between the outer peripheral surface of the nut body 852 and the inner peripheral surfaces of the respective members of the reducer 840. The outer peripheral surface of the nut body 852 is slidable relative to the inner peripheral surfaces of the respective members of the reducer 840. An internal thread is formed on the inner peripheral surface of the nut body 852. The internal thread is formed over the entire area of ​​the nut body 852 in the direction along the central axis 840C. In FIG. 21, the female thread is shown only in a portion of the nut body 852.

[0219] The connecting portion 853 is located near the lower end of the nut body 852. The connecting portion 853 protrudes radially outward from the outer peripheral surface of the nut body 852, centered on the central axis 840C of the nut body 852. The connecting portion 853 extends around the entire circumference of the nut body 852. In other words, the connecting portion 853 is annular. The central axis 840C of the connecting portion 853 substantially coincides with the central axis 840C of the nut body 852. The upward-facing surface of the connecting portion 853 is in surface contact with the downward end surface of the output member 844 of the reducer 840. The connecting portion 853 and the output member 844 are fixed together, for example, by a bolt B. In other words, the connecting portion 853 is connected to the output member 844. Then, the connecting portion 853 and therefore the entire nut 851 receive the torque of the output member 844 and rotate integrally with the output member 844 around the central axis 840C of the nut 851.

[0220] The screw shaft 855 extends from the inside to the outside of the nut 851. The screw shaft 855 is cylindrical. A central axis 840C of the screw shaft 855 substantially coincides with the central axis 840C of the reducer 840. The diameter of the screw shaft 855 is smaller than the inner diameter of the nut body 852. A male thread is cut on the outer peripheral surface of the screw shaft 855. The male thread is formed over the entire area of ​​the screw shaft 855 in the direction along the central axis 840C. The screw shaft 855 is inserted through the nut 851 and therefore the reducer 840. A lower portion of the screw shaft 855 penetrates the lower surface of the case body 826. The lower portion of the screw shaft 855 is exposed to the outside of the case 825.

[0221] The plurality of balls 858 are interposed between the inner peripheral surface of the nut body 852 and the outer peripheral surface of the screw shaft 855. The plurality of balls 858 are held between the female thread of the nut body 852 and the male thread of the screw shaft 855. The plurality of balls 858 guide the relative rotation between the nut body 852 and the screw shaft 855. Note that FIG. 21 shows six of the plurality of balls 858 as representatives. The number of balls 858 is not limited to six.

[0222] The central axis 840C of the reducer 840 is referred to as the power central axis 840C. Because the central axis 840C of the reducer body 841 extends substantially in the Z direction, the power central axis 840C is aligned vertically. As described above, the nut 851 rotates in accordance with the torque of the reducer 840. This rotation of the nut 851 is transmitted to the screw shaft 855 via the balls 858. At the same time, the screw shaft 855 moves upward or downward along the power central axis 840C. In this way, in the conversion mechanism 850, the torque generated by the reducer 840 is converted into linear motion in a direction along the power central axis 840C.

[0223] <Link mechanism> 21, the dozer blade driving mechanism 801 includes a link mechanism 820. The link mechanism 820 is located below a case 825. As shown in FIG. 22, the link mechanism 820 includes a link 822 and a joint 821.

[0224] As shown in Fig. 21, when the link 822 is viewed in the Y direction, the link 822 extends linearly in the X direction. On the other hand, as shown in Fig. 22, when the link 822 is viewed in the Z direction, the link 822 includes a U-shaped leg 823 and a body 824 that extends linearly from the bottom of the U in the leg 823 to the opposite side to the bifurcation of the U. The end of the body 824 opposite to the leg 823 is attached to the rear surface of the dozer blade 608 by an attachment means. Various attachment means can be used, for example, bolting or welding.

[0225] The lower end of the screw shaft 855 is located between the two prongs of the U-shape of the leg portion 823. A joint 821 passes through the leg portion 823 and the lower end of the screw shaft 855. That is, the leg portion 823 and the screw shaft 855 are connected via the joint 821. The joint 821 is prevented from coming off the leg portion 823 by a retaining means (not shown). The joint 821 is cylindrical. The central axis of the joint 821 extends approximately in the Y direction. That is, the central axis of the joint 821 is approximately parallel to the central axis of the support shaft 817, which serves as the rotation center of the connecting member 815. The central axis of the joint 821 is also approximately parallel to the central axis of the pin 827 in the case 825. The joint 821 connects the leg portion 823 and the screw shaft 855 so as to be rotatable relative to each other. In other words, the leg portion 823 and the screw shaft 855 are rotatable relative to each other around the joint 821 .

[0226] <Operation of the Fifth Embodiment> The lifting and lowering operation of the dozer blade 608 will now be described. Assume that the members related to the dozer blade drive mechanism 801 are in the first position shown in Figs. 19 and 21. In this first position, the amount of protrusion of the screw shaft 855 from the case main body 826 is a first value. Also, in this first position, the connecting member 815 is inclined slightly downward with respect to an imaginary line that passes through the support shaft 817 and extends in the X direction.

[0227] First, the raising operation of the dozer blade 608 will be described. In the first position described above, when the output shaft 833 of the motor 831 rotates, the bevel gear 834 of the motor 831 meshes with the bevel gear 843 of the reducer 840, causing the output shaft 833 of the reducer 840 and therefore the nut 851 to rotate about the power central axis 840C. This rotation of the nut 851 drives the linear movement of the screw shaft 855 through the relative rotation between the nut 851 and the screw shaft 855. Specifically, as shown in FIG. 23 , the screw shaft 855 moves upward relative to the nut 851. At the same time, the amount of protrusion of the screw shaft 855 from the case main body 826 becomes smaller than the first value. When the screw shaft 855 moves upward, the joint 821 moves upward together with the screw shaft 855. As a result, the link 822 connected to the joint 821, the dozer blade 608 connected to the link 822, and the connecting member 815 connected to the dozer blade 608 move upward. In other words, the upward movement of the screw shaft 855 acts as a force that pulls the link 822, the dozer blade 608, and the connecting member 815 upward. On the other hand, the connecting member 815 is in a state where it can rotate around the support shaft 817. Therefore, the upward movement of the screw shaft 855 rotates the link 822, the dozer blade 608, and the connecting member 815 upward around the support shaft 817 as shown by arrow 800A in FIG. 23 . In this way, the link mechanism 820 constituted by the joint 821 and the link 822 has the function of transmitting the linear motion converted by the conversion mechanism 850 to the dozer blade 608 and the connecting member 815 as the rotational motion of the dozer blade 608 .

[0228] As described above, the joint 821 is connected to the connecting member 815 via the link 822 and the dozer blade 608. In this regard, when the joint 821 moves upward, strictly speaking, the joint 821 moves on an imaginary circle centered on the central axis 817A of the support shaft 817, which is the rotation center of the connecting member 815. In other words, when the screw shaft 855 moves up and down, the joint 821 does not simply move linearly in the Z direction but rotates. To allow such rotation of the joint 821, the case 825 of this embodiment is swingably connected to the extension wall portion 812. Therefore, when the joint 821 rotates, the case main body 826, which is integrated with the joint 821, rotates around the pin 827. As a result, as shown in FIG. 23 , the power central axis 840C is slightly inclined with respect to the Z direction. As such, the extension direction of the power center axis 840C does not always coincide with the Z direction, and may be tilted within a range of approximately 15 degrees relative to the Z direction, for example. Including such cases, the power center axis 840C can be said to be aligned with the Z direction as long as it extends vertically as a whole. Note that the tilt angle of the power center axis 840C shown in Figure 23 is an example used to explain the rotation of the case main body 826, and does not necessarily coincide with the actual angle.

[0229] Next, the lowering operation of the dozer blade 608 will be described. Now, from the first position described above, assume that the output shaft 833 of the reducer 840, and therefore the nut 851, rotates in the opposite direction to that of the raising operation in response to the drive of the motor 831. This rotation of the nut 851 drives the linear movement of the screw shaft 855 through the relative rotation between the nut 851 and the screw shaft 855. Specifically, as shown in FIG. 24 , the screw shaft 855 moves downward relative to the nut 851. At the same time, the amount of protrusion of the screw shaft 855 from the case main body 826 becomes greater than the first value. This downward movement of the screw shaft 855 acts as a force pushing the link 822, the dozer blade 608, and the connecting member 815 downward. Meanwhile, the connecting member 815 is in a state in which it can rotate about the support shaft 817. Therefore, as shown by arrow 800B in FIG. 24, the movement of the screw shaft 855 rotates the link 822, the dozer blade 608, and the connecting member 815 downward around the support shaft 817. When the dozer blade 608 rotates in this manner, the link 822 and the joint 821 transmit the linear motion converted by the conversion mechanism 850 to the dozer blade 608 and the connecting member 815 as the rotational motion of the dozer blade 608. As with the lifting operation, when the dozer blade 608 rotates, the case main body 826 rotates around the pin 827 as the rotational center in the opposite direction to that in the lifting operation. At the same time, the power center axis 840C is slightly inclined with respect to the Z direction. As with FIG. 23, the inclination angle of the power center axis 840C shown in FIG. 24 is an example for explaining the rotation of the case main body 826 and does not necessarily correspond to the actual angle.

[0230] <Effects of the Fifth Embodiment> (5-1) Suppose that the reducer 840 is attached to the lower body 810 so that its central axis 840C extends in the Y direction. In this case, the outer diameter of the reducer 840 is restricted by the need to avoid interference between the ground and the upper body 530. In this regard, in the excavator 800 of this embodiment, the reducer 840 is attached to the lower body 810 so that its central axis 840C extends generally vertically. Therefore, even if the outer diameter of the reducer 840 is increased, a space for mounting the reducer 840 on the excavator 800 can be ensured. With the configuration of this embodiment, it becomes possible to employ a relatively large reducer 840 in order to output a large torque, for example.

[0231] An external force may act on the dozer blade 608 from the front side. The load acting on the dozer blade 608 from the front side has a component mainly in the X direction. Therefore, as described in (1-3) of the first embodiment, this load is unlikely to act as a force that moves each component in a direction intersecting the X direction. In other words, this load is unlikely to act as a force that moves the screw shaft 855, which extends roughly in the Z direction, upward, and is unlikely to affect the conversion mechanism 850 and the power generating unit 830. With the configuration of this embodiment, it is possible to prevent the external force acting on the dozer blade 608 from reaching the reducer 840 and the motor 831. This contributes to preventing the power generating unit 830 from becoming larger, for example, as described in (1-3) of the first embodiment.

[0232] (5-2) In the backhoe 800 of this embodiment, a so-called ball screw mechanism is used as a mechanism for converting power between the power generating device 830 and the link mechanism 820. The use of such a ball screw mechanism is suitable for converting the rotational motion of the reducer 840 into linear motion.

[0233] (5-3) In the excavator 800 of this embodiment, the reducer 840 is cylindrical. The nut 851 and the screw shaft 855, which are the conversion mechanism 850, are housed inside the reducer 840. In this way, by using the interior of the reducer 840 as a space for housing the conversion mechanism 850, the overall installation space for the power generating device 830 and the conversion mechanism 850 can be reduced. This allows the structural parts of the case 825 that houses the power generating device 830 and the conversion mechanism 850, and the lower body 810 in which the case 825 is arranged, to be made compact.

[0234] (5-4) As described in the operation of the above embodiment, in the configuration of this embodiment, when joint 821 moves in response to the up-and-down movement of screw shaft 855, joint 821 moves on an imaginary circle centered on central axis 817A of support shaft 817. If case main body 826 were not rotatably supported, a universal joint, for example, would need to be interposed between joint 821 and screw shaft 855 to allow rotation of joint 821. However, in this case, providing a universal joint between joint 821 and screw shaft 855 increases the number of parts and complicates the connection configuration between joint 821 and screw shaft 855. In this regard, in backhoe 800 of this embodiment, case main body 826 is rotatably supported by extension wall 812. This makes it possible to realize a configuration that allows movement of joint 821, with respect to the connection between conversion mechanism 850 and link mechanism 820, while suppressing an increase in the number of parts and a complicated configuration.

[0235] <Modification of the fifth embodiment> The fifth embodiment can be modified as follows: The first to fifth embodiments and the following modifications can be combined and implemented as long as no technical contradiction occurs.

[0236] The shape of the case 825 is not limited to the example in the above embodiment. The case 825 may be any shape that can accommodate the power generating device 830. The case 825 may be eliminated. When the case 825 is eliminated, for example, the housing 832 of the motor 831 may be fixed to the outer surface of the reducer body 841, thereby allowing the motor 831 and the reducer 840 to be configured as an integrated assembly. When the case 825 is eliminated, for example, the reducer 840 may be directly connected to the vehicle body 803. This point will be explained in the next modified example.

[0237] The configuration for rotatably connecting the power generating unit 830 to the vehicle body 803 is not limited to the example of the above embodiment. For example, when the case 825 is eliminated as in the above modified example, a shaft-shaped member may protrude to both the left and right sides from the outer peripheral surface of the reducer body 841. The shaft-shaped member may then be rotatably supported by the extension wall portion 812. The power generating unit 830 may be connected to the vehicle body 803 so as to be rotatable about a central axis parallel to the central axis of rotation of the connecting member 815. The vehicle body 803 is not limited to the lower body 810, and may also be the operating mechanism of the upper body 530 or the traveling device 550.

[0238] It is not essential that the power generating unit 830 be rotatably connected to the vehicle body 803. When the power generating unit 830 is not rotatably connected to the vehicle body 803, for example, a universal joint may be provided between the joint 821 and the screw shaft 855. When raising and lowering the dozer blade 608, it is only necessary that the power generating unit 830, the conversion mechanism 850, the link mechanism 820, the dozer blade 608, and the connecting member 815 are connected so that each member can operate smoothly.

[0239] As described above, the structure of the vehicle body 803 for attaching the power generating unit 830 to the vehicle body 803 is not limited to the example of the above embodiment. This structure is not important as long as the power generating unit 830 can be attached to the vehicle body 803. As described above, the vehicle body 803 includes the operating mechanism of the traveling device 550 in addition to the lower body 810 and the upper body 530.

[0240] The shape of the reducer 840 is not limited to the example in the above embodiment. That is, the reducer 840 is not limited to a cylindrical shape. For example, the reducer main body 841 may be a rectangular tube. If the reducer 840 is cylindrical, various components of the conversion mechanism 850 can be disposed inside the reducer 840. Furthermore, the reducer 840 may be a shape other than a cylindrical shape, for example. Regardless of the shape of the reducer 840, it is sufficient that the reducer 840 can change the rotational speed of the motor 831 and output the changed rotational speed. Then, the reducer 840 and the conversion mechanism 850 can be appropriately connected so that the output of the reducer 840 can be transmitted to the conversion mechanism 850.

[0241] The configuration of the conversion mechanism 850 is not limited to the example of the above embodiment. The conversion mechanism 850 only needs to convert the rotational motion from the power generating device 830 into linear motion. For example, in the conversion mechanism 850, the ball 858 may be eliminated from between the nut 851 and the screw shaft 855. The inner circumferential surface of the nut 851 and the outer circumferential surface of the screw shaft 855 may be screwed together. Even in this case, the screw shaft 855 can be linearly moved through the relative rotation between the nut 851 and the screw shaft 855.

[0242] The configuration of the link mechanism 820 is not limited to the example of the above embodiment. The link mechanism 820 only needs to be able to transmit the linear motion converted by the conversion mechanism 850 as a rotational motion of the dozer blade 608. For example, in the above embodiment, the link 822 is connected to the dozer blade 608. Instead of this configuration, the shape of the link 822 may be changed so that the link 822 is connected to the connecting member 815. The linear motion of the threaded shaft 855 may then be transmitted from the joint 821 and ultimately the link 822 to the connecting member 815. Even in this case, the dozer blade 608 can be raised and lowered by, for example, moving the connecting member 815 up and down together with the joint 821. The link mechanism 820 may also be configured without using the joint 821. Furthermore, the link mechanism 820 may be configured with three or more link components.

[0243] The configuration of the connecting member 815 is not limited to the example of the above embodiment. The connecting member 815 only needs to be connected to the vehicle body 803 and to allow the dozer blade 608 to be attached to the side opposite to the point where it is connected to the vehicle body 803.

[0244] The manner in which the connecting member 815 is connected to the vehicle body 803 is not limited to the example in the above embodiment. For example, the connecting member 815 and the support shaft 817 may be fixed together. The support shaft 817 may then be connected to the main portion 811 of the lower body 810 so that the support shaft 817 is rotatable relative to the main portion 811. Any manner may be used as long as the connecting member 815 can be rotatably connected to the vehicle body 803.

[0245] The transmission mechanism for inputting the rotation of the motor 831 to the reducer 840 is not limited to one that uses a bevel gear. For example, a so-called worm gear mechanism may be used as this transmission mechanism. As long as the rotation of the motor 831 can be input to the reducer 840, the configuration of the transmission mechanism is not important.

[0246] It is not essential that the power generating device 830 includes the reducer 840. For example, the power generating device 830 may be configured with only the motor 831, and the motor 831 may be connected to the conversion mechanism 850. In this case, it is conceivable to arrange the motor 831 so that the central axis of its output shaft 833 is along the Z direction. When the power generating device 830 is configured with only the motor 831, the central axis of the output shaft 833 of the motor 831 can form the power central axis. It is sufficient that the power generating device 830 includes the electric motor 831.

[0247] The configuration of the dozer blade 608 is not limited to the example of the above embodiment. The dozer blade 608 may have any configuration that can achieve the required purpose, such as grading, digging, and stirring up earth and sand.

[0248] The construction machine to which the dozer blade drive mechanism 801 is applied is not limited to the example of the above embodiment. For example, the dozer blade drive mechanism 801 can also be applied to a bulldozer or a compact track loader.

[0249] In the above embodiments, if an object is made up of multiple objects, the multiple objects may be integrated, and conversely, if an object is made up of a single object, it may be divided into multiple objects. Regardless of whether the objects are integrated or not, it is sufficient that the object of the invention can be achieved.

[0250] Sixth Embodiment A sixth embodiment of the dozer blade drive mechanism will be described below with reference to Figures 25 to 29. In Figures 25 to 29, parts that function the same as or substantially the same as those in Figures 1 to 24 are given the same reference numerals as those in Figures 1 to 24. In the following description, parts that overlap with the first to fifth embodiments may be omitted or simplified as appropriate.

[0251] As shown in Fig. 25, the backhoe 870 includes a vehicle body 803. The configuration of the vehicle body 803 is the same as that of the fifth embodiment, except for the configuration of an extension wall portion 813, which will be described later. In this embodiment, up, down, left, right, front, and rear are defined in the same manner as in the first embodiment.

[0252] The lower body 810 will be described in detail. As shown in Figures 25 and 26, the lower body 810 includes a main portion 811 and an extension wall portion 813. The main portion 811 has an outer shape of, for example, a rectangular parallelepiped. The main portion 811 houses various mechanisms necessary for operating the backhoe 870. Note that the main portion 811 is not limited to a box shape as long as it can accommodate necessary parts and the like. Hereinafter, the position that is the center of the left and right of the main portion 811 in the Y direction may be referred to as the center of the main body.

[0253] The extension wall portion 813 is located on the front side of the main portion 811. The extension wall portion 813 is fixed to the main portion 811. The extension wall portion 813 has, for example, a rectangular parallelepiped shape. The extension wall portion 813 is hollow inside. Note that the extension wall portion 813 may have any shape as long as it can support a power generating device 873, which will be described later.

[0254] As shown in Figures 25 and 26, the backhoe 870 is equipped with a pair of traveling devices 550, a work attachment 510, and a dozer blade 608. The configurations of the traveling devices 550 and the work attachment 510 are the same as those in the first embodiment. The configuration of the dozer blade 608 is the same as that in the second embodiment. Note that the upper body 530 and the work attachment 510 are not shown in Figure 26. Also, Figure 26 shows only one of the pair of traveling devices 550.

[0255] <Dozer blade drive mechanism> The excavator 870 is equipped with a dozer blade drive mechanism 871. The dozer blade drive mechanism 871 is equipped with two sets of power transmission mechanisms 872. Note that FIGS. 25 and 26 show only one of the two sets of power transmission mechanisms 872. The two sets of power transmission mechanisms 872 are provided on the left and right sides of the center of the main body. The two sets of power transmission mechanisms 872 are configured symmetrically. Therefore, in the following, the power transmission mechanism 872 will be described using as an example the one of the two sets of power transmission mechanisms 872 that is located on the left side of the center of the main body.

[0256] As shown in FIGS. 25 and 26, the power transmission mechanism 872 includes a connecting member 879. As shown in FIG. 25, the connecting member 879 extends forward from the main portion 811 of the lower body 810. As shown in FIG. 26, the connecting member 879 is located between the lower body 810 and the traveling device 550 in the Y direction. As shown in FIG. 25, the connecting member 879 includes a rod-shaped main body 879A and a connecting portion 879B located at one longitudinal end of the main body 879A. The connecting portion 879B is plate-shaped. As shown in FIG. 26, the main surface of the connecting portion 879B faces the main portion 811 of the lower body 810. As already explained, the main surface is the surface with the largest area among the outer surfaces of a plate-shaped object. A support shaft 817 penetrates the connecting portion 879B. The support shaft 817 is fixed to the main portion 811 of the lower body 810. That is, the connecting portion 879B is connected to the main portion 811 via the support shaft 817. The support shaft 817 is cylindrical. A central axis 817A of the support shaft 817 extends substantially in the Y direction. Note that the central axis 817A of the support shaft 817 is not shown in FIG. 26. The connecting member 879 is rotatable up and down relative to the main portion 811 around the support shaft 817. That is, the central axis 817A of the support shaft 817 is the central axis of rotation of the connecting member 879.

[0257] As shown in Fig. 25, a main body 879A of the connecting member 879 extends linearly forward from a connecting portion 879B. The dozer blade 608 can be attached to the front end of the main body 879A of the connecting member 879, i.e., the side of the connecting member 879 opposite to the point where the connecting member 879 is connected to the lower body 810, using an attachment means. Various attachment means can be used, such as bolt fixing or welding. In this embodiment, the connecting member 879 is attached to the rear surface of the dozer blade 608. Note that Figs. 27 to 29 show the dozer blade 608 in a simplified form.

[0258] 26 , the power transmission mechanism 872 includes a power generating device 873. The power generating device 873 is located inside the extension wall portion 813 of the lower body 810. The power generating device 873 includes a motor 874, a reducer 875, and a transmission member 876.

[0259] The motor 874 is a drive source for the power generating device 873. The motor 874 includes a housing 874A and an output shaft 874B. The motor 874 is electrically driven and operates in response to power supplied from a battery (not shown). The housing 874A is fixed to the inner wall of the extension wall portion 813. Most of the output shaft 874B is located inside the housing 874A. A portion of the output shaft 874B protrudes from the housing 874A toward the opposite side from the center of the main body. The output shaft 874B is cylindrical. A central axis F1 of the output shaft 874B extends in the Y direction. The output shaft 874B is rotatable relative to the housing 874A. The output shaft 874B rotates around its own central axis F1. The output shaft 874B is rotatable in both forward and reverse directions in response to power supplied to the motor 874. Hereinafter, the central axis F1 of the output shaft 874B may be referred to as the central axis F1 of the motor 874. In addition, in this embodiment, the axis that substantially coincides with the central axis F1 of the output shaft 874B is uniformly designated by the symbol F1.

[0260] The reducer 875 is adjacent to the motor 874 in the direction along the central axis F1 of the motor 874. In the Y direction, the reducer 875 is located on the opposite side of the motor 874 across the center of the base body. The reducer 875 is fixed to the inner wall of the extension wall portion 813. The reducer 875 is connected to the output shaft 874B of the motor 874. The torque of the output shaft 874B of the motor 874 is input to the reducer 875. The reducer 875 amplifies the torque of the output shaft 874B of the motor 874 at a predetermined ratio and outputs the amplified torque. The reducer 875 may be, for example, an eccentric oscillating gear type or a planetary gear type. Any type of reducer may be used as the reducer 875 as long as it is configured to amplify and output the torque from the motor 874.

[0261] The transmission member 876 is adjacent to the reducer 875 in the direction along the central axis F1 of the motor 874. The transmission member 876 is located on the opposite side of the reducer 875 from the motor 874. The transmission member 876 is connected to the reducer 875. The transmission member 876 is cylindrical. The central axis F1 of the transmission member 876 substantially coincides with the central axis F1 of the motor 874. The torque output by the reducer 875 is input to the transmission member 876. The transmission member 876 receives the torque from the reducer 875 and rotates about the central axis F1 of the transmission member 876. In other words, the transmission member 876 outputs torque centered on the central axis F1 of the motor 874. As described above, the power generating device 873 uses the motor 874 as a drive source to generate torque centered on the central axis F1 of the motor 874. Hereinafter, the central axis F1 of the motor 874 may be referred to as the central axis F1 of the power generating device 873. The central axis F1 of the power generating device 873 is parallel to the central axis of the connecting member 879 about which the motor 874 rotates.

[0262] <Eccentric cam> As shown in FIGS. 25 and 26 , the power transmission mechanism 872 includes a first eccentric cam 880. As shown in FIG. 26 , the first eccentric cam 880 is adjacent to the transmission member 876 in the direction along the central axis F1 of the power generating device 873. The first eccentric cam 880 is located on the opposite side of the transmission member 876 from the reducer 875. The first eccentric cam 880 includes a first cam main body 881 and a first input shaft 882. The first input shaft 882 is connected to the transmission member 876. The first input shaft 882 is cylindrical. The central axis F1 of the first input shaft 882 substantially coincides with the central axis F1 of the transmission member 876. The first input shaft 882 is coaxial with the transmission member 876 and rotates integrally therewith. That is, the first input shaft 882 receives torque generated by the power generating device 873 and rotates about the central axis F1 of the power generating device 873. In the Y direction, approximately half of the first input shaft 882 that is closer to the transmission member 876 is located within the extension wall portion 813. The first input shaft 882 is rotatably supported by a bearing 885 within the extension wall portion 813. Approximately half of the first input shaft 882 that is opposite to the transmission member 876 protrudes from the extension wall portion 813. The bearing 885 is fixed to the inner wall of the extension wall portion 813. As a result of the first input shaft 882 being supported by the bearing 885, the central axis F1 of the first input shaft 882 is always maintained at a constant position.

[0263] The first cam body 881 is located outside the extension wall portion 813. In the Y direction, the first cam body 881 is located at the same position as the body 879A of the connecting member 879. As shown in FIG. 27 , the first cam body 881 is located above the body 879A of the connecting member 879 in the Z direction. The first cam body 881 has a cylindrical outer shape. The central axis of the cylinder of the first cam body 881 extends in the Y direction. The first cam body 881 has a first through hole 881H. The first through hole 881H penetrates the first cam body 881 in the Y direction. The central axis F1 of the first through hole 881H is offset from the central axis F1 of the cylinder of the first cam body 881. On the other hand, the central axis F1 of the first through hole 881H substantially coincides with the central axis F1 of the first input shaft 882 and therefore the power generating unit 873. The diameter of the first through hole 881H is approximately the same as the diameter of the first input shaft 882. The first input shaft 882 is positioned inside the first through hole 881H. The inner surface of the first through hole 881H and the first input shaft 882 are fixed together. The first cam main body 881 is coaxial with the first input shaft 882 and rotates integrally with the first input shaft 882. That is, the central axis F1 of the first input shaft 882 is the rotation central axis of the first cam main body 881 and therefore the first eccentric cam 880. Hereinafter, this rotation central axis may be referred to as the first rotation central axis F1. Note that in FIGS. 25 and 27, for convenience, the power generating unit 873 is represented by a circle having a diameter smaller than the first through hole 881H.

[0264] The entire outer peripheral surface of first cam body 881 constitutes first cam surface 881A. In the circumferential direction centered on the central axis of the cylinder of first cam body 881, a portion of first cam surface 881A contacts main body 879A of connecting member 879 from above.

[0265] 27, the power transmission mechanism 872 includes a second eccentric cam 890. The second eccentric cam 890 is located below the first eccentric cam 880. In detail, in the Z direction, the second eccentric cam 890 is located on the opposite side to the first eccentric cam 880 across the main body 879A of the connecting member 879.

[0266] The second eccentric cam 890 includes a second cam body 891 and a second input shaft 892. The second eccentric cam 890 is configured to have the same shape and dimensions as the first eccentric cam 880. That is, the second input shaft 892 is cylindrical, similar to the first input shaft 882. The center axis F2 of the second input shaft 892 extends in the Y direction. Although not shown, the second input shaft 892 is located at approximately the same position as the first input shaft 882 in both the X and Y directions. Like the first input shaft 882, a portion of the second input shaft 892 is located within the extension wall portion 813. The remaining portion of the second input shaft 892 protrudes outside the extension wall portion 813. The second input shaft 892 is rotatably supported by a bearing on the inner wall of the extension wall portion 813. The second input shaft 892 is supported by a bearing and is therefore rotatable about a central axis F2 of the second input shaft 892. As with the first input shaft 882, the position of the central axis F2 of the second input shaft 892 is always maintained constant.

[0267] The second cam body 891 is located at approximately the same position as the first cam body 881 in both the X and Y directions. The outer shape of the second cam body 891 is cylindrical, similar to the first cam body 881. The central axis of the cylinder of the second cam body 891 extends in the Y direction. The second cam body 891 has a second through hole 891H. The second through hole 891H penetrates the second cam body 891 in the Y direction. The central axis F2 of the second through hole 891H is offset from the central axis of the cylinder of the second cam body 891. A portion of the second input shaft 892 that protrudes from the extension wall portion 813 is located inside the second through hole 891H. The inner surface of the second through hole 891H and the second input shaft 892 are fixed together. Therefore, when the second input shaft 892 rotates, the second cam body 891 is coaxial with the second input shaft 892 and rotates integrally therewith. That is, the central axis F2 of the second input shaft 892 is the central axis of rotation of the second cam body 891 and therefore the entire second eccentric cam 890. Hereinafter, this central axis of rotation may be referred to as the second central axis of rotation F2. The second central axis of rotation F2 is parallel to the first central axis of rotation F1.

[0268] The entire outer peripheral surface of second cam main body 891 constitutes second cam surface 891A. In the circumferential direction centered on the central axis of the cylinder of second cam main body 891, a portion of second cam surface 891A contacts main body 879A of connecting member 879 from the downward side. That is, second cam surface 891A contacts main body 879A of connecting member 879 from the side opposite to first cam surface 881A. In both the X and Y directions, second cam surface 891A is located at approximately the same position as first cam surface 881A. Then, second cam surface 891A and first cam surface 881A sandwich main body 879A of connecting member 879 from above and below.

[0269] The relationship between the attitudes of the first eccentric cam 880 and the second eccentric cam 890 will be described. The following description of the attitudes of the first eccentric cam 880 and the second eccentric cam 890 is based on the assumption that the first eccentric cam 880 and the second eccentric cam 890 are viewed in the Y direction. The attitude of the first eccentric cam 880 refers to the relative positional relationship between the first rotation center axis F1 and the central axis of the cylinder of the first cam main body 881. The attitude of the first eccentric cam 880 can be determined by a first defined direction, which is the direction in which the central axis of the cylinder of the first cam main body 881 is located when viewed from the first rotation center axis F1. For example, in the first mode shown in FIG. 27 , the first defined direction is the upward direction. The first defined direction can also be considered to be the direction in which the farthest portion of the first cam surface 881A is located when viewed from the first rotation center axis F1. The posture of the second eccentric cam 890 is the relative positional relationship between the second rotation center axis F2 and the central axis of the cylinder of the second cam body 891. The posture of the second eccentric cam 890 can be determined by a second specified direction, which is the direction in which the central axis of the cylinder of the second cam body 891 is located when viewed from the second rotation center axis F2. For example, in the first mode shown in FIG. 27, the second specified direction is the upward direction. The second specified direction can also be said to be the direction in which the farthest portion of the second cam surface 891A is located when viewed from the second rotation center axis F2. In this embodiment, the posture of the first eccentric cam 880 and the posture of the second eccentric cam 890 are the same. For example, in the first mode shown in FIG. 27, the first specified direction and the second specified direction are approximately the same. In other words, the first eccentric cam 880 and the second eccentric cam 890 are in a relationship in which they are moved parallel to each other in the Z direction while maintaining the same orientation. As will be described later, the first eccentric cam 880 and the second eccentric cam 890 rotate in conjunction with each other. Even when the first eccentric cam 880 and the second eccentric cam 890 rotate, their orientations always approximately match. In other words, the first eccentric cam 880 and the second eccentric cam 890 rotate in conjunction with each other so that the first specified direction and the second specified direction match.

[0270] <Belt> As shown in FIG. 27 , the power transmission mechanism 872 includes an endless belt 888. The belt 888 constitutes an interlocking mechanism. As shown in FIG. 26 , the belt 888 is located inside the extension wall portion 813. As shown in FIG. 27 , the belt 888 is wound around the first input shaft 882 of the first eccentric cam 880 and the second input shaft 892 of the second eccentric cam 890. As described above, the first input shaft 882 receives torque transmitted from the power generating device 873. Accordingly, the first input shaft 882 rotates. The belt 888 transmits the rotation of the first input shaft 882 to the second input shaft 892. Specifically, the belt 888 travels around the first input shaft 882 and the second input shaft 892 in response to the operation of the first input shaft 882. The second input shaft 892 rotates in response to the operation of the belt 888. That is, the belt 888 rotates the second input shaft 892 in conjunction with the first input shaft 882 .

[0271] <Operation of the Sixth Embodiment> Assume now that the dozer blade drive mechanism 871 is in the first position shown in FIG. 27. In this first position, the first prescribed direction related to the attitude of the first eccentric cam 880 and the second prescribed direction related to the attitude of the second eccentric cam 890 are upward, as described above. In relation to the fact that the first prescribed direction and the second prescribed direction are upward, the rotation position of the dozer blade 608 in the first position is the upper limit position of the rotation range of the dozer blade 608. In this first position, the distance from the first rotation central axis F1 to the contact point between the first cam surface 881A and the main body 879A of the connecting member 879 is minimum within one rotation of the first eccentric cam 880. In addition, in this first position, the distance from the second rotation central axis F2 to the contact point between the second cam surface 891A and the main body 879A of the connecting member 879 is maximum within one rotation of the second eccentric cam 890. In the first mode, the main body 879A of the connecting member 879 extends substantially in the X direction.

[0272] Now, in the first mode shown in FIG. 27, suppose that the first input shaft 882 of the first eccentric cam 880 rotates counterclockwise on the page of FIG. 27 in response to the drive of the motor 874. Then, as shown by arrow W1 in FIG. 28, the first cam main body 881 rotates counterclockwise together with the first input shaft 882. Furthermore, when the first input shaft 882 rotates, the second input shaft 892 rotates counterclockwise together with the first input shaft 882 as shown by arrow W2 in FIG. 28 through the transmission of power by the belt 888. Then, the second cam main body 891 rotates together with the rotation of the second input shaft 892. As a result of these rotations, the postures of both the first eccentric cam 880 and the second eccentric cam 890 change. Specifically, in the position of the first eccentric cam 880 shown in Fig. 28, the central axis of the cylinder of the first cam body 881 is located forward when viewed from the first rotation center axis F1. In addition, in the position of the second eccentric cam 890 shown in Fig. 28, the central axis of the cylinder of the second cam body 891 is located forward when viewed from the second rotation center axis F2. With such rotation of the first eccentric cam 880 and the second eccentric cam 890, the connecting member 879 rotates downward as shown by arrow W3 in Fig. 28. This rotation of the connecting member 879 is driven by the contact action between the first cam surface 881A and the second cam surface 891A and the connecting member 879.

[0273] Specifically, when first eccentric cam 880 rotates counterclockwise from the first position, the distance from first rotation center axis F1 to the contact point between first cam surface 881A and main body 879A of connecting member 879 gradually increases due to the eccentricity of first rotation center axis F1. At the same time, first cam surface 881A gradually presses connecting member 879 downward. On the other hand, when second eccentric cam 890 rotates counterclockwise from the first position, the distance from second rotation center axis F2 to the contact point between second cam surface 891A and main body 879A of connecting member 879 gradually decreases due to the eccentricity of second rotation center axis F2. At the same time, second cam surface 891A supports connecting member 879 upward while allowing connecting member 879 to move downward. In this way, when the first eccentric cam 880 and the second eccentric cam 890 rotate, the first cam surface 881A and the second cam surface 891A guide the downward rotation of the connecting member 879. Then, when the connecting member 879 rotates, the dozer blade 608 rotates downward together with the connecting member 879 around the support shaft 817.

[0274] Note that, here, the downward rotation of the dozer blade 608 has been described using as an example a case where the first eccentric cam 880 and the second eccentric cam 890 rotate approximately 90 degrees from the first state, but the amount of rotation of the first eccentric cam 880 and the second eccentric cam 890 is not limited to approximately 90 degrees. Depending on the amount of rotation of the first eccentric cam 880 and the second eccentric cam 890, the dozer blade 608 may rotate further downward than in the second state shown in Fig. 28. In other words, the rotation position of the dozer blade 608 shown in Fig. 28 does not indicate the lower limit position of the rotation range of the dozer blade 608.

[0275] 28, assume that the first input shaft 882 of the first eccentric cam 880 rotates clockwise on the paper surface of FIG. 28 in response to the drive of the motor 874. Then, the entire first eccentric cam 880 rotates clockwise, and the entire second eccentric cam 890 also rotates clockwise in conjunction with the first eccentric cam 880. With this rotation of the first eccentric cam 880 and the second eccentric cam 890, the first cam surface 881A and the second cam surface 891A guide the upward rotation of the connecting member 879. Then, when the connecting member 879 rotates, the dozer blade 608 rotates upward together with the connecting member 879 around the support shaft 817.

[0276] <Effects of the Sixth Embodiment> (6-1) As described in the operation of the above embodiment, in the back shovel 870 of this embodiment, the dozer blade 608 can be raised and lowered through the contact action between the first cam surface 881A and the second cam surface 891A and the connecting member 879.

[0277] As described in (1-3) of the first embodiment, an external force may act on the dozer blade 300 from the front side. As already described, the load associated with this external force mainly has a component in the X direction. Therefore, this load is unlikely to act on parts located in the Z direction with respect to the main body 879A of the connecting member 879. In other words, this load is unlikely to act on the first eccentric cam 880 located on the upper side with respect to the main body 879A of the connecting member 879. Similarly, this load is unlikely to act on the second eccentric cam 890 located on the lower side with respect to the main body 879A of the connecting member 879. Therefore, with the configuration of this embodiment, even if a load acts on the dozer blade 300 from the front side, it is possible to prevent this load from being input to the power generating device 873 via the first eccentric cam 880. Furthermore, the configuration of this embodiment can prevent the above-mentioned load from being input to the power generating device 873 via the path of the second eccentric cam 890, the belt 888, and the first eccentric cam 880. By being able to prevent the load from being input to the power generating device 873, it is possible to prevent the power generating device 873 from becoming larger, similar to (1-3) of the first embodiment.

[0278] (6-2) In the excavator 870 of this embodiment, eccentric cams are arranged above and below the main body 879A of the connecting member 879. The connecting member 879 is sandwiched between these upper and lower eccentric cams. By arranging the eccentric cams above and below the connecting member 879 in this manner, the supporting state of the connecting member 879 is stabilized when guiding the rotation of the connecting member 879. Furthermore, in the excavator 870 of this embodiment, the two eccentric cams are operated in conjunction with each other by the belt 888. This allows the postures of the two eccentric cams to be constantly synchronized. This allows the connecting member 879 to be smoothly guided by the two eccentric cams.

[0279] <Modification of the Sixth Embodiment> The sixth embodiment can be modified as follows: The first to sixth embodiments and the following modifications can be combined with each other within the scope of technical compatibility.

[0280] The movable range of the dozer blade 608 is not limited to the example of the above embodiment. To achieve a favorable movable range when using the dozer blade 608, the connecting member 879 and other members may be attached to the backhoe 870 in consideration of the attitudes of the first eccentric cam 880 and the second eccentric cam 890.

[0281] The interlocking mechanism is not limited to the example of the above embodiment. The interlocking mechanism may be any mechanism that can rotate the first eccentric cam 880 and the second eccentric cam 890 in conjunction with each other. For example, a chain may be used as the interlocking mechanism instead of the belt 888. When a chain is used as the interlocking mechanism, a plurality of teeth may be formed on the outer circumferential surfaces of the first input shaft 882 and the second input shaft 892 around which the chain is wound, and these may be used as sprockets.

[0282] The configuration of the first eccentric cam 880 is not limited to the example of the above embodiment. It is sufficient that the outer shape of the first eccentric cam 880, when viewed toward its own rotational axis, includes a portion that deviates from a circle centered on the rotational axis. The first eccentric cam 880 is positioned so that this portion forms the first cam surface 881A that contacts the connecting member 879. For example, the outer shape may be an arc or an ellipse centered at a position deviated from the rotational axis of the first eccentric cam 880. The first cam surface 881A that contacts the connecting member 879 is not limited to the entire outer peripheral surface of the first eccentric cam 880, but may be a portion of the outer peripheral surface of the first eccentric cam 880. Similar to the first eccentric cam 880, the configuration of the second eccentric cam 890 is not limited to the example of the above embodiment.

[0283] It is not essential that the postures of the first eccentric cam 880 and the second eccentric cam 890 are the same. Also, it is not essential that the first eccentric cam 880 and the second eccentric cam 890 have the same shape and dimensions. It is sufficient that the connecting member 879 can be rotated up and down through contact with each cam surface.

[0284] The configuration for transmitting the torque of the power generating unit 873 to each eccentric cam is not limited to the example in the above embodiment. For example, another member may be interposed between the first eccentric cam 880 and the power generating unit 873. The arrangement of the power generating unit 873 may be changed from that in the above embodiment so that the torque of the power generating unit 873 is transmitted to the second eccentric cam 890 instead of the first eccentric cam 880. Two power generating units 873 may be provided, and each may transmit torque to both the first eccentric cam 880 and the second eccentric cam 890 individually. It is sufficient that the torque of the power generating unit 873 can be transmitted to at least one of the eccentric cams.

[0285] One of the two eccentric cams may be eliminated. When one of the two eccentric cams is eliminated, for example, a dozer blade drive mechanism 871A and a power transmission mechanism 872A shown in Fig. 29 may be employed. In Fig. 29, parts that function the same as or substantially the same as those in Figs. 25 to 28 are given the same reference numerals as those in Figs. 25 to 28. As in Fig. 27, in the reference state shown in Fig. 29, the connecting member 879 and the dozer blade 608 are positioned at the upper limit of their movable ranges.

[0286] In the power transmission mechanism 872A shown in Fig. 29, the connecting member 879 includes an extension 879C in addition to a main body 879A and a connecting portion 879B. The extension 879C is located on the opposite side of the connecting portion 879B from the main body 879A. The extension 879C is, for example, rod-shaped. The extension 879C extends linearly on the same straight line as the main body 879A.

[0287] The rotation direction of the connecting member 879 will be described below, assuming that the power transmission mechanism 872A is viewed from the Y direction. As described above, in the reference state shown in FIG. 29 , the dozer blade 608 is positioned at the upper limit of its movable range. That is, in the reference state shown in FIG. 29 , the central axis of the cylinder of the first cam body 881 is positioned upward as viewed from the first rotation central axis F1. At this time, the distance from the first rotation central axis F1 to the contact point between the first cam surface 881A and the body 879A of the connecting member 879 is minimized within one rotation of the first eccentric cam 880. Under this circumstance, the rotation direction on the side where the contact point is located as viewed from the first rotation central axis F1 is referred to as the first rotation direction U1. The first rotation direction U1 is the counterclockwise direction on the paper surface of FIG. 29 . On the other hand, the direction opposite to the first rotation direction U1 is referred to as the second rotation direction U2. The second rotation direction U2 is the clockwise direction on the paper surface of FIG.

[0288] The power transmission mechanism 872A includes a spring 896. In the X direction, the spring 896 is located on the opposite side of the support shaft 817 from the first eccentric cam 880. In the Y direction, the spring 896 is located at the same position as the extension 879C of the connecting member 879. In the Z direction, the spring 896 is located above the extension 879C of the connecting member 879. The spring 896 is cylindrical as a whole. The lower end of the spring 896 along the central axis is fixed to the extension 879C of the connecting member 879. Although not shown in the drawings, the upper end of the spring 896 is fixed to the vehicle body 803. An example of the vehicle body 803 is the main portion 811 of the lower body 810. The spring 896 applies a downward biasing force to the extension 879C of the connecting member 879. In other words, the spring 896 applies a biasing force to the connecting member 879 so that the connecting member 879 rotates in the second rotation direction U2 relative to the vehicle body 803. At this time, the rotation center of the connecting member 879 is the support shaft 817, as described above.

[0289] The power transmission mechanism 872A includes a damper 895. A spring 896 is inserted through the damper 895. The damper 895 is, for example, hydraulic. Although not shown, the damper 895 includes a damper body and a rod. The damper body is cylindrical. The lower end of the damper body along its central axis is fixed to an extension 879C of the connecting member 879. The rod protrudes upward from inside the damper body relative to the damper body. The upper end of the rod is fixed to the vehicle body 803. An example of the vehicle body 803 is the main portion 811 of the lower body 810. The damper body has a damping function that damps the movement of the rod.

[0290] The operation of the power transmission mechanism 872A shown in FIG. 29 will be described. First, the downward rotation of the dozer blade 608 will be described. Note that, as above, clockwise and counterclockwise in the following description refer to the plane of FIG. 29. Now, assume that the first eccentric cam 880 rotates counterclockwise from the reference state shown in FIG. 29. Then, through contact between the first cam surface 881A and the main body 879A of the connecting member 879, the connecting member 879 rotates about the support shaft 817 toward the first rotation direction U1. Specifically, as the first eccentric cam 880 rotates counterclockwise, the distance from the first rotation central axis F1 to the contact point between the first cam surface 881A and the main body 879A of the connecting member 879 gradually increases. At the same time, the first cam surface 881A gradually presses the main body 879A of the connecting member 879 downward. At the same time, the main body 879A of the connecting member 879 and therefore the dozer blade 608 rotate in the first rotation direction U1. That is, the dozer blade 608 rotates downward. At this time, the damping function of the damper 895 causes the connecting member 879 and the dozer blade 608 to rotate gently.

[0291] Next, the upward rotation of the dozer blade 608 will be described. Assume that the dozer blade 608 is positioned below the upper limit position. In this state, assume that the first eccentric cam 880 rotates clockwise. If the spring 896 were not present, the first cam surface 881A would move away from the main body 879A of the connecting member 879 as the first eccentric cam 880 rotates clockwise. However, in the power transmission mechanism 872A shown in FIG. 29 , the extension 879C of the connecting member 879 is biased toward the second rotation direction U2 by the spring 896. Accordingly, the main body 879A of the connecting member 879 is pressed downward against the first cam surface 881A. Therefore, when the first eccentric cam 880 moves away from the main body 879A of the connecting member 879, the main body 879A of the connecting member 879 rotates upward following the first cam surface 881A. That is, the main body 879A of the connecting member 879 rotates upward around the support shaft 817. At the same time, the dozer blade 608 rotates upward. In this way, in the power transmission mechanism 872A shown in Fig. 29, the dozer blade 608 can be raised and lowered while maintaining a balance between the first eccentric cam 880 and the spring 896.

[0292] The use of the power transmission mechanism 872A shown in FIG. 29 has the following advantages. When two eccentric cams are used, the shape and dimensions of the eccentric cams must be appropriately designed so that they can smoothly guide the rotation of the connecting member 879. Furthermore, when two eccentric cams are used, two bearings and an interlocking mechanism must be provided, which tends to increase the overall number of parts. Furthermore, when two eccentric cams are used, the two eccentric cams must be attached to the vehicle body 803 with their postures aligned, which can be time-consuming. In this regard, the use of the spring 896 can eliminate the above-mentioned complex design, the increased number of parts, and the time-consuming attachment work.

[0293] In the power transmission mechanism 872A shown in FIG. 29, the damper 895 is not essential. In the power transmission mechanism 872A shown in FIG. 29 , the positions of the first eccentric cam 880 and the spring 896 in the X direction may be interchanged. That is, the spring 896 may be disposed on the front side of the support shaft 817, and the first eccentric cam 880 may be disposed on the rear side of the support shaft 817. Furthermore, the first eccentric cam 880 and the spring 896 may both be disposed on the same side of the support shaft 817 in the X direction. In this case, the first eccentric cam 880 and the spring 896 may be positioned above and below the connecting member 879. The key is that the direction in which the first eccentric cam 880 rotates the connecting member 879 as the first eccentric cam 880 rotates is opposite to the direction in which the spring 896 biases the connecting member 879.

[0294] When using only one eccentric cam to raise and lower the connecting member 879 and therefore the dozer blade 608, it is not essential to employ the spring 896. Any mechanism may be used as long as it can rotate the connecting member 879 and therefore the dozer blade 608 up and down. Note that even without using any mechanism, if an eccentric cam is disposed below the main body 879A of the connecting member 879, the weight of the main body 879A of the connecting member 879 and the contact action of the eccentric cam with the connecting member 879 can rotate the connecting member 879 and therefore the dozer blade 608 up and down.

[0295] The shape of the extension wall portion 813 is not limited to the example in the above embodiment, as long as the extension wall portion 813 is configured to be able to support the power generating device 873, the eccentric cams, and the like. The extension wall portion 813 may be eliminated. In this case, the power generating device 873 and the eccentric cams may be attached to the main portion 811 of the lower body 810.

[0296] Either one of the left or right power generating devices 873 may be eliminated. At the same time, the eccentric cam on the side where the power generating device 873 is eliminated may be eliminated. When eliminating either one of the left or right power generating devices 873, the connecting member 879 on the side where the power generating device 873 is eliminated may be rotatably supported by the support shaft 817 on the side opposite to the connection point with the dozer blade 608, for example. Eliminating either one of the left or right power generating devices 873 corresponds to eliminating either one of the left or right power transmission mechanisms 872.

[0297] The configuration of the connecting member 879 is not limited to the example of the above embodiment. The connecting member 879 only needs to be connected to the vehicle body 803 and be able to attach the dozer blade 608 to the side opposite the point of connection with the vehicle body 803. The vehicle body 803 includes the operating mechanisms of the lower body 810, the upper body 530, and the traveling device 550.

[0298] It is not essential that the power generating device 873 include the reducer 875 and the transmission member 876. For example, the power generating device 873 may be configured with only the motor 874, and the motor 874 may be directly connected to the eccentric cam. The power generating device 873 may include the electric motor 874.

[0299] The configuration of the dozer blade 608 is not limited to the example of the above embodiment. The dozer blade 608 may have any configuration that can achieve the required purpose, such as grading, digging, and stirring up earth and sand.

[0300] The construction machine to which the dozer blade drive mechanism 871 is applied is not limited to the example of the above embodiment. For example, the dozer blade drive mechanism 871 can also be applied to a bulldozer or a compact track loader.

[0301] In the above embodiments, if an object is made up of multiple objects, the multiple objects may be integrated, and conversely, if an object is made up of a single object, it may be divided into multiple objects. Regardless of whether the objects are integrated or not, it is sufficient that the object of the invention can be achieved.

[0302] Seventh Embodiment A seventh embodiment of the dozer blade drive mechanism will be described below with reference to Figures 30 to 32. Note that the drawings may show components enlarged to facilitate understanding. The dimensional ratios of the components may differ from the actual ones or from those in other drawings. In Figures 30 to 32, parts that are the same as or function substantially the same as those in Figures 1 to 29 are given the same reference numerals as in Figures 1 to 29. In the following description, parts that overlap with the first to sixth embodiments may be omitted or simplified as appropriate.

[0303] As shown in FIG. 30, an excavator 900, which is a construction machine, includes a vehicle body 901. The vehicle body 901 further includes an upper body 530 and a lower body 902. The configuration of the upper body 530 is the same as that of the first embodiment. The configuration of the lower body 902 will be described later. The upper body 530 is located on the opposite side of the lower body 902 from the ground G. In this embodiment, up, down, left, right, front, and rear are defined in the same way as in the first embodiment. The upper body 530 is rotatable left and right relative to the lower body 902, centering on an axis extending substantially in the Z direction.

[0304] The lower body 902 will be described in detail. The lower body 902 includes a main section 903 and a connecting wall section 904. The outer shape of the main section 903 is, for example, a rectangular parallelepiped. The main section 903 houses various mechanisms required to operate the backhoe 900. Note that the main section 903 is not limited to a box shape, and may be any shape that can accommodate required parts, etc.

[0305] The connecting wall portion 904 is located forward relative to the main portion 903. The connecting wall portion 904 protrudes forward from the front surface of the main portion 903. The connecting wall portion 904 is fixed to the front surface of the main portion 903. The connecting wall portion 904 is, for example, a rectangular plate. The main surfaces of the connecting wall portion 904 face left and right. The main surfaces are the outer surfaces of the plate-shaped member with the largest area. The connecting wall portion 904 is located near the center of the main portion 903 in the Y direction. In the Z direction, the connecting wall portion 904 is located near the upper end of the main portion 903. The external dimensions of the connecting wall portion 904 are significantly smaller than the external dimensions of the power generating device 30, which will be described later.

[0306] The excavator 900 includes a pair of traveling devices 550, a work attachment 510, and a dozer blade 300. The configurations of the traveling devices 550 and the work attachment 510 are the same as those in the first embodiment. The configuration of the dozer blade 300 is basically the same as that in the first embodiment. However, the dozer blade 300 includes an attachment structure 330 instead of the attachment piece 320 in the first embodiment. That is, the attachment structure 330 is fixed to the rear surface of the dozer blade body 310. The attachment structure 330 is a wall portion for attaching the power generating unit 30, which will be described later. The attachment structure 330 may have any shape as long as it can attach the power generating unit 30.

[0307] <Dozer blade drive mechanism> The excavator 900 is equipped with a dozer blade drive mechanism 900A. The dozer blade drive mechanism 900A is equipped with a pair of connecting members 907. The pair of connecting members 907 are located on both the left and right sides of the lower body 902. The configuration of the connecting members 907 is the same as that of the arm in the first embodiment. That is, the connecting member 907 is long in the front-to-rear direction. A support shaft 915 passes through the rear end of the connecting member 907. The support shaft 915 is fixed to the main section 903 of the lower body 902. That is, the connecting member 907 is connected to the main section 903 via the support shaft 915. The support shaft 915 is located rearward of the connecting wall section 904 of the lower body 902. In addition, in the Z direction, the support shaft 915 is located downward of the connecting wall section 904. The support shaft 915 is cylindrical. The central axis 915A of the support shaft 915 extends substantially in the Y direction. As indicated by arrow 907V in FIG. 30 , the connecting member 907 can rotate up and down relative to the main section 903 around the central axis 915A of the support shaft 915. In other words, the central axis 915A of the support shaft 915 is the central axis of rotation of the connecting member 907. The dozer blade 300 is attached to the front end of the connecting member 907, i.e., the side of the connecting member 907 opposite the connection point between the lower body 902 and the main section 903, using an attachment means. Various attachment means can be used, such as bolting or welding. Note that in FIG. 30 , the connecting member 907 is partially cut away to make it easier to understand the positional relationship of the various components.

[0308] The dozer blade drive mechanism 900A includes a power generating device 30. The power generating device 30 is attached to a mounting structure 330 of the dozer blade 300. The configuration of the power generating device 30 is the same as that of the first embodiment. That is, the power generating device 30 includes a motor 31 serving as a drive source, a reducer 35, and a transmission member. Note that the transmission member is not shown in the drawings. As described in the first embodiment, the motor 31 is an electrically driven motor that operates in response to power supplied from a battery (not shown). The output shaft 33 of the motor 31 is rotatable with respect to the housing. The output shaft 33 rotates about its own central axis 31A. The reducer 35 is aligned with the motor 31 in the direction along the central axis 31A of the output shaft 33 of the motor 31. The reducer 35 is connected to the output shaft 33 of the motor 31. The torque output by the output shaft 33 of the motor 31 is input to the reducer 35. The reducer 35 amplifies the torque from the motor 31 and outputs it to the transmission member. The transmission member is aligned with the reducer 35 in a direction along the central axis 31A of the output shaft 33 of the motor 31. The transmission member is located on the opposite side of the reducer 35 from the motor 31. The transmission member receives torque from the reducer 35 and outputs torque centered on the central axis 31A of the output shaft 33 of the motor 31. The rotation direction of the transmission member coincides with the rotation direction of the output shaft 33 of the motor 31. Hereinafter, the central axis 31A of the output shaft 33 of the motor 31 will be referred to as the central axis 31A of the power generating unit 30. When the power generating unit 30 is attached to the dozer blade 300, the central axis 31A of the power generating unit 30 extends in the Y direction. In other words, the central axis 31A of the power generating unit 30 is approximately parallel to the rotation central axis of the connecting member 907. Although not shown in the drawings, the power generating device 30 is covered with, for example, a cover to prevent soil and sand from adhering thereto.

[0309] The dozer blade driving mechanism 900A includes a link mechanism 910. The link mechanism 910 includes a first link 911 and a second link 912. The first link 911 and the second link 912 are linear link components when viewed in a plan view facing the Y direction.

[0310] A first end of the first link 911 is connected to the connecting wall portion 904 of the lower body 902. Specifically, a first support shaft 916 passes through the first end of the first link 911. The first support shaft 916 is fixed to the connecting wall portion 904. That is, the first link 911 is connected to the connecting wall portion 904 via the first support shaft 916. The first support shaft 916 is cylindrical. The central axis of the first support shaft 916 extends substantially in the Y direction. That is, the central axis of the first support shaft 916 is substantially parallel to the rotation central axis of the connecting member 907. The first link 911 is in a state where it can rotate relatively to the first support shaft 916. The first link 911 is prevented from coming off from the first support shaft 916 by a retaining means (not shown).

[0311] A second end of the first link 911 is connected to a first end of the second link 912. Specifically, a second support shaft 917 penetrates between the second end of the first link 911 and the first end of the second link 912. The second support shaft 917 is cylindrical. The central axis of the second support shaft 917 extends substantially in the Y direction. That is, the central axis of the second support shaft 917 is substantially parallel to the central axis of the first support shaft 916. The second support shaft 917 is prevented from coming off the first link 911 and the second link 912 by a retaining means (not shown). Both the first link 911 and the second link 912 are rotatable relative to the second support shaft 917. Therefore, the first link 911 and the second link 912 are rotatable relative to each other around the second support shaft 917.

[0312] The second end of the second link 912 is fixed to a transmission member of the power generating unit 30. The second end of the second link 912 rotates integrally with the transmission member. In other words, the second link 912 rotates around the central axis 31A of the motor 31. As described above, the link mechanism 910 connects the power generating unit 30 and the connecting wall 904, which is a part of the vehicle body 901.

[0313] <Operation of Seventh Embodiment> The raising and lowering operation of the dozer blade 300 will be described. As shown in FIG. 30, the posture of each component of the dozer blade drive mechanism 900A when the dozer blade body 310 is in contact with the ground G is referred to as the base posture. In the base posture, the connecting member 907 is arranged roughly along the X direction. In addition, in the base posture, the first link 911 and the second link 912 are arranged in a V-shape with the second support shaft 917 at the lower end when the backhoe 900 is viewed facing the Y direction. Hereinafter, the clockwise direction on the paper surface of FIG. 30, that is, the clockwise direction when the backhoe 900 is viewed from the left in plan, will be referred to as the first direction 31P, and the counterclockwise direction will be referred to as the second direction 31Q.

[0314] Assume now that the components of the dozer blade drive mechanism 900A are in the base position. Assume that the output shaft 33 of the motor 31 rotates in the first direction 31P from this position. Then, as shown in FIG. 31 , the second link 912 and the first link 911 operate in conjunction with each other, and the power generating unit 30 approaches the connecting wall 904. Specifically, as shown in FIG. 31 , the minor angle formed between the first link 911 and the second link 912 when viewed from the Y direction becomes smaller than that in the base position. At the same time, as shown by the arrow 900P in FIG. X, the power generating unit 30 and the dozer blade 300 move upward relative to the base position. Specifically, the power generating unit 30 and the dozer blade 300 rotate upward around the support shaft 915. To achieve this rotational movement, the minor angle formed between the first link 911 and the second link 912 becomes smaller, and thus the torque generated by the power generating device 30 is transmitted to the dozer blade 300 and the connecting member 907 so that the dozer blade 300 rotates upward. In other words, the link mechanism 910 transmits the torque generated by the power generating device 30 to the dozer blade 300 and the connecting member 907 as a rotational movement of the dozer blade 300 about the rotation central axis of the connecting member 907. The minor angle is the angle formed between the first link 911 and the second link 912 that is smaller than 180 degrees.

[0315] As shown in FIG. 30 , it is assumed that the components of the dozer blade drive mechanism 900A are again in the base posture. From this state, it is assumed that the output shaft 33 of the motor 31 is rotated in the second direction 31Q. For example, when the work attachment 510 is used to excavate the ground G, the excavator 900 can move the dozer blade 300 downward from an imaginary plane formed by extending the underside of the crawler of the traveling device 550. When the output shaft 33 of the motor 31 is rotated in the second direction 31Q, the second link 912 and the first link 911 operate in conjunction with each other, as shown in FIG. 32 , causing the power generating unit 30 to move away from the connecting wall 904. Specifically, the recessive angle between the first link 911 and the second link 912 when viewed from the Y direction becomes larger than that in the base posture. At the same time, the power generating unit 30 and the dozer blade 300 move downward from the base posture, as indicated by the arrow 900Q in FIG. 32 . The power generating unit 30 and the dozer blade 300 rotate downward around the support shaft 915. To achieve this rotational movement, the minor angle formed between the first link 911 and the second link 912 increases, and the torque generated by the power generating unit 30 is transmitted to the dozer blade 300 and the connecting member 907 so that the dozer blade 300 rotates downward. In other words, the link mechanism 910 transmits the torque generated by the power generating unit 30 to the dozer blade 300 and the connecting member 907 as a rotational movement of the dozer blade 300 around the rotation central axis of the connecting member 907.

[0316] <Effects of the Seventh Embodiment> According to the configuration of this embodiment, the rotation of the output shaft 33 of the motor 31 can be transmitted to the dozer blade 300 via the first link 911 and the second link 912. This allows the dozer blade 300 to be raised and lowered. That is, according to the configuration of this embodiment, the dozer blade 300 can be raised and lowered using the motor 31 as a power source. In adopting such an electric lifting mechanism for the dozer blade 300, in this embodiment, the power generating unit 30 is attached to the dozer blade 300 and is connected to the lower body 902 by a link mechanism 910. Here, consider a comparative example in which the power generating unit 30 is attached to the lower body 902 and is connected to the dozer blade 300 by the link mechanism 910, as in the first embodiment. In this comparative example, the power generating unit 30 is disposed near the front surface of the main section 903 of the lower body 902. The external dimensions of the power generating unit 30 are accordingly large. Therefore, in the comparative example, a large space for the power generating device 30 is allocated near the front surface of the main part 903. As a result, the space for arranging other members near the front surface of the main part 903 is reduced.

[0317] In this regard, in the configuration of this embodiment, the power generating unit 30, which has a large outer dimension, is attached to the dozer blade 300. In other words, the power generating unit 30 is disposed at a position away from the front surface of the main section 903. In this case, it is not necessary to place a large member near the front surface of the main section 903. All that is required is to secure a space near the front surface of the main section 903 for attaching the first support shaft 916, which has a small outer dimension. With this configuration of this embodiment, it is easy to secure a free space near the front surface of the main section 903. It becomes possible to place other members in this free space.

[0318] <Modification of the Seventh Embodiment> The seventh embodiment can be modified as follows: The first to seventh embodiments and the following modifications can be combined with each other within the scope of no technical contradiction.

[0319] The configuration of the link mechanism 910 is not limited to the example of the above embodiment. The dimensions and shape of each link component can be changed as appropriate from the example of the above embodiment. Furthermore, the number of link components constituting the link mechanism 910 can also be changed as appropriate from the example of the above embodiment. The link mechanism 910 only needs to be configured to transmit the torque generated by the power generating unit 30 as a rotational movement of the dozer blade 300 about the central axis 915A of the support shaft 915.

[0320] The configuration of the connecting member 907 is not limited to the example of the above embodiment. The connecting member 907 only needs to be rotatably connected to the vehicle body 901 and to allow the dozer blade 300 to be attached to the side opposite the point of connection with the vehicle body 901. Also, as with the modified example of the first embodiment, the manner in which the connecting member 907 is connected to the vehicle body 901 is not limited to the example of the above embodiment. The connection point on the vehicle body 901 for connecting the connecting member 907 to the vehicle body 901 is not limited to the main portion 903 of the lower body 902.

[0321] As with the modified example of the first embodiment, the configuration of the power generating device 30 is not limited to the example of the above embodiment. The power generating device 30 may be configured to include an electric motor 31 as a drive source and to generate torque centered on a central axis parallel to the central axis of rotation of the connecting member 907.

[0322] The structure of the dozer blade 300 for attaching the power generating unit 30 to the dozer blade 300 is not limited to the example of the above embodiment. As long as the power generating unit 30 can be attached to the dozer blade 300, any structure is possible. For example, the power generating unit 30 may be attached to the dozer blade body 310.

[0323] The construction machine to which the dozer blade drive mechanism 900A is applied is not limited to the example of the above embodiment. For example, the dozer blade drive mechanism 900A can also be applied to a bulldozer or a compact track loader.

[0324] In the above embodiments, if an object is made up of multiple objects, the multiple objects may be integrated, and conversely, if an object is made up of a single object, it may be divided into multiple objects. Regardless of whether the objects are integrated or not, it is sufficient that the object of the invention can be achieved. [Explanation of symbols]

[0325] G...ground L1...first line segment L2...Second line segment LX...Arm segment 21...1st support shaft 22…Second support shaft 23…Third support shaft 30,631,720,830,873...Power generating device 31,722,831,874...Motor 70...Arm 40,820,910...Link mechanism 50...1st link 60...Second link 100...Connection mechanism 300,608...Dozer blade 400...Lower housing 410...Main body of the housing 420…Front of the housing 500, 600, 650, 700, 700A, 800, 870, 900... Excavator 511...Bucket 520, 653, 703, 803, 901...Body 600A, 651, 701, 701A, 801, 871, 871A, 900A...Dozer blade drive mechanism 601...Control device 611...Travel crawler 618...Drive sprocket 630...Power transmission mechanism 633,715,815,879,907...Connecting members 635...Universal joint 637...Driven sprocket 639...Bearing 640...Transmission member 641...First member 641B…First facing surface 641C...recess 642...Second member 642C…Convex part 642A…Second opposing surface 665…Support wall part 670...Power transmission mechanism 705...Lower body 710...Upper body 840...Reducer 844...Output member 850...Conversion mechanism 851...Nut 855...Screw shaft 858...ball 880...First eccentric cam 881A...First cam surface 890...Second eccentric cam 891A...Second cam surface 888...Belt 896...Spring

Claims

1. a connecting member that is rotatably connected to a vehicle body of the construction machine and that can attach a dozer blade to the side opposite to the connecting point with the vehicle body; a power generating device including an electric motor as a drive source, and configured to generate torque centered on a central axis parallel to the central axis of rotation of the connecting member; a link mechanism that transmits the torque generated by the power generating device as a rotational motion of the dozer blade about the rotation central axis, When viewed in a direction parallel to the central axis, the central axis is located closer to the dozer blade than the center of a line segment connecting a connection point of the connecting member with the vehicle body and a connection point of the link mechanism with the dozer blade. Dozer blade drive mechanism.

2. the link mechanism includes a first link that receives torque from the power generating device and rotates about the central axis, and a second link that is rotatably connected to both the first link and the dozer blade, When viewed in a direction parallel to the central axis, a line segment connecting the central axis and a connection point of the first link with the second link is defined as a first line segment, and a line segment connecting the connection point of the second link with the first link and a connection point of the second link with the dozer blade is defined as a second line segment, The length of the first line segment is 50% or more and 200% or less of the length of the second line segment.

2. The dozer blade drive mechanism of claim 1.

3. the link mechanism includes a first link that receives torque from the power generating device and rotates about the central axis, and a second link that is rotatably connected to both the first link and the dozer blade, Assuming that the dozer blade is in contact with the ground on which the construction machine is traveling, the connection point of the second link with the dozer blade is located below the connection point of the second link with the first link.

2. The dozer blade drive mechanism of claim 1.

4. When viewed in a direction parallel to the central axis, a line segment connecting the central axis and a connection point of the first link with the second link is defined as a first line segment, and a line segment connecting the connection point of the second link with the first link and a connection point of the second link with the dozer blade is defined as a second line segment, Assuming that the dozer blade is in contact with the ground, the minor angle formed by the first line segment and the second line segment is equal to or greater than 75 degrees and equal to or less than 105 degrees.

4. The dozer blade drive mechanism of claim 3.

5. When it is assumed that the dozer blade is in contact with the ground, the first line segment is parallel to the ground.

5. The dozer blade drive mechanism of claim 4.

6. a power generating device that is disposed within a traveling crawler of the construction machine, includes an electric motor, and generates torque; a connecting member that is connected to the power generating device, that is rotatable by receiving torque from the power generating device, and that can have a dozer blade attached to the side opposite to the connecting point with the power generating device; Dozer blade drive mechanism.

7. two sets of power transmission mechanisms, each set including the power generating device and the connecting member; The two sets of power transmission mechanisms are provided corresponding to one and the other of the pair of traveling crawlers of the construction machine.

7. The dozer blade drive mechanism of claim 6.

8. a universal joint provided in each of the two sets of power transmission mechanisms, the universal joint being located at a mounting location of the connecting member to the dozer blade and connecting the connecting member to the dozer blade; a control device that controls the electric motors of the two power transmission mechanisms, The control device is capable of individually controlling each of the electric motors of the two sets of power transmission mechanisms.

8. The dozer blade drive mechanism of claim 7.

9. a driven sprocket having an annular shape coaxial with the rotational axis of the power generating device, a plurality of teeth formed on an outer circumferential surface thereof, and through which the power generating device is inserted; a bearing disposed between the driven sprocket and the power generating device, the bearing supporting the driven sprocket rotatably relative to the power generating device; the driven sprocket is located at an end opposite to the driving sprocket across the center of the traveling crawler, within the traveling crawler; The connecting member extends from a point of connection with the power generating device toward a side opposite to the drive sprocket.

7. The dozer blade drive mechanism of claim 6.

10. a power generating device attached to a body of the construction machine, including an electric motor, and configured to generate torque; a connecting member that is connected to the power generating device, that is rotatable by receiving torque from the power generating device, and that can have a dozer blade attached to the side opposite to the connecting point with the power generating device; Dozer blade drive mechanism.

11. The wall portion of the vehicle body for mounting the power generating device straddles the center between the pair of crawlers.

11. The dozer blade drive mechanism of claim 10.

12. two sets of power transmission mechanisms, each set including the power generating device and the connecting member; The two sets of power transmission mechanisms are located on one side and the other side of the center between the pair of crawlers.

11. The dozer blade drive mechanism of claim 10.

13. a power generating device that is attached to an upper body that is rotatable relative to a lower body of the construction machine, includes an electric motor that serves as a drive source, and generates torque; a connecting member that is connected to the power generating device, that is rotatable by receiving torque from the power generating device, and that can have a dozer blade attached to the side opposite to the connecting point with the power generating device; Dozer blade drive mechanism.

14. The construction machine is equipped with an excavation bucket, When viewed in a direction parallel to the rotation center axis of the power generating device, the direction in which the dozer blade is located as viewed from the connection point is defined as a first direction, and the bucket is located on the first direction side as viewed from the connection point.

14. The dozer blade drive mechanism of claim 13.

15. the power generating device has a transmission member that outputs torque corresponding to rotation of the electric motor, the transmission member includes a first member and a second member arranged in a direction along a rotation central axis of the power generating device, the first member has a first flat surface facing the second member and a recess recessed from the first flat surface and extending along a first axis parallel to the first flat surface; The second member has a second flat surface facing the first flat surface, and a convex portion protruding from the second flat surface at a position facing the recess and extending along the first axis.

14. A dozer blade drive mechanism according to any one of claims 6, 10 or 13.

16. a connecting member that is rotatably connected to a vehicle body of the construction machine and that can attach a dozer blade to the side opposite to the connecting point with the vehicle body; a power generating device including an electric motor serving as a drive source and generating torque; When the axis along the top and bottom of the construction machine is the power center axis, a conversion mechanism that converts the torque generated by the power generating device into linear motion in a direction along the power central axis; a link mechanism that transmits the linear motion converted by the conversion mechanism as a rotational motion of the dozer blade; Dozer blade drive mechanism.

17. The conversion mechanism is a nut that rotates by receiving torque from the power generating device; a screw shaft inserted through the nut; a plurality of balls interposed between the nut and the screw shaft; 17. The dozer blade drive mechanism of claim 16.

18. the power generating device has a reducer that changes the rotational speed of the electric motor and outputs the changed rotational speed; the reducer is cylindrical with the power central axis as its central axis, and has an output member on one end face side in a direction along the power central axis for outputting torque to the nut, the nut is connected to the output member of the reducer, The screw shaft and the nut are inserted into the reducer.

18. The dozer blade drive mechanism of claim 17.

19. The power generating device is connected to the vehicle body so as to be rotatable about a central axis parallel to the rotation central axis of the connecting member.

17. The dozer blade drive mechanism of claim 16.

20. a connecting member that is rotatably connected to a vehicle body of the construction machine and that can attach a dozer blade to the side opposite to the connecting point with the vehicle body; a power generating device including an electric motor serving as a drive source and generating torque; an eccentric cam that receives torque generated by the power generating device and rotates about a rotation center axis that is parallel to the rotation center axis of the connecting member, The cam surface, which is the outer peripheral surface of the eccentric cam, is in contact with the connecting member. Dozer blade drive mechanism.

21. When the eccentric cam is a first eccentric cam, the cam surface is a first cam surface, and the rotation center axis of the first eccentric cam is a first rotation center axis, a second eccentric cam that rotates about a second rotation central axis that is parallel to the first rotation central axis and is located on the opposite side of the connecting member from the first eccentric cam; a linkage mechanism that links and rotates the first eccentric cam and the second eccentric cam, a second cam surface, which is an outer peripheral surface of the second eccentric cam, contacts the connecting member from the side opposite to the first cam surface, the first eccentric cam and the second eccentric cam have the same shape and dimensions; The first eccentric cam and the second eccentric cam rotate in conjunction with each other so that a direction in which a portion of the first cam surface farthest from the first rotation central axis is located, as viewed from the first rotation central axis, coincides with a direction in which a portion of the second cam surface farthest from the second rotation central axis is located, as viewed from the second rotation central axis.

21. The dozer blade drive mechanism of claim 20.

22. a spring that applies a biasing force to the connecting member so that the connecting member rotates in one direction relative to the vehicle body; The one-way side is the side opposite to the side on which the contact point is located when viewed from the rotation center axis of the eccentric cam in a state where the distance from the rotation center axis of the eccentric cam to the contact point between the cam surface and the connecting member is minimum.

21. The dozer blade drive mechanism of claim 20.

23. a connecting member that is rotatably connected to a vehicle body of a construction machine and has a dozer blade attached to the side opposite to the connecting point with the vehicle body; a power generating device attached to the dozer blade, including an electric motor as a drive source, and configured to generate torque about a central axis parallel to the rotation central axis of the connecting member; a link mechanism that connects the power generating device and the vehicle body and transmits the torque generated by the power generating device as a rotational movement of the dozer blade about the rotation central axis. Dozer blade drive mechanism.

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