Construction machinery, drive systems and drive devices

Abstract

To provide a construction machine capable of driving a work element rotatably connected to a construction machine body with a low output drive device or while suppressing the output of the drive device.SOLUTION: A construction machine 1 of one embodiment is a shovel. The construction machine 1 includes a work element 20 having a boom, an arm, and a bucket rotatably connected to a construction machine main body 10, a driving device 30 that outputs rotational force, and a link mechanism 40 that connects the driving device 30 and the work element 20 and inputs the rotational force of the driving device 30 to the work element 20.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a construction machine in which a working element is driven by a drive device, a drive system, and a drive device. [Background technology]

[0002] A typical driving device of a construction machine is a hydraulic actuator such as a hydraulic cylinder, etc. The hydraulic actuator is usually operated by the pressure of hydraulic oil discharged from a hydraulic pump in response to the power of the engine.

[0003] For example, a typical hydraulic excavator, which is an example of a construction machine, has a working element including a boom, an arm, and a bucket connected to an upper rotating body that is part of the construction machine body, and the boom, the arm, and the bucket are each driven by a hydraulic cylinder.

[0004] Meanwhile, the electrification of construction machinery has recently been attracting attention. For example, Patent Document 1 discloses an excavator in which the boom is directly driven by an electric motor connected to the shaft at the base end of the boom, while the arm and bucket are each driven by a hydraulic cylinder. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 11-343642 Summary of the Invention [Problem to be solved by the invention]

[0006] The advantages of electrifying construction machinery include reduced environmental impact and noise, while the disadvantage is a lack of power (insufficient output).

[0007] In Patent Document 1, the shaft at the base end of the boom is directly driven by an electric motor. However, in this case, the torque borne by the electric motor to rotate the boom increases. Therefore, depending on the size of the electric motor, for example, there may be cases where it is not possible to ensure sufficient torque to drive the boom, and it may become necessary to increase the size of the drive device including the electric motor.

[0008] Therefore, when electrifying construction machinery, even if it is not possible to ensure a sufficiently large output in the drive unit, in other words, it is desirable to devise a way to drive the working elements in a desirable manner while preventing the machine from becoming too large.

[0009] The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide a construction machine, a drive system, and a drive unit that can drive a working element that is rotatably connected to the construction machine body with a low-output drive unit or while suppressing the output of the drive unit. [Means for solving the problem]

[0010] A construction machine according to one embodiment comprises a working element rotatably connected to the construction machine body, a drive unit that outputs rotational force, and a link mechanism that connects the drive unit and the working element and inputs the rotational force of the drive unit to the working element.

[0011] The drive device may be provided on the construction machine body, and the link mechanism may have a drive link directly connected to the drive device, and a connecting link connecting the drive link and the working element. In this case, the length from the connection position of the drive link to the construction machine body to the connection position of the connecting link may be shorter than the length from the connection position of the work element to the construction machine body to the connection position of the connecting link. Furthermore, when the working element assumes a predetermined posture, the angle formed by the line connecting the connection position of the drive link to the construction machine body and the connection position of the connecting link and the line connecting the connection position of the connecting link to the driving link and the connection position of the working element may be 45 degrees or more and 90 degrees or less, and the angle formed by the line connecting the connection position of the connecting link to the driving link and the connection position of the working element and the line connecting the connection position of the working element to the construction machine body and the connection position of the connecting link may be 45 degrees or more and 90 degrees or less.

[0012] The working element may include a first element that is rotatably connected directly to the construction machine body, and a second element that is rotatably connected to the first element at a position different from the connection position between the construction machine body and the first element, and the link mechanism may include a drive link that is directly connected to the drive device, and a connecting link that connects the drive link and the second element. In this case, the drive device may be provided on the construction machine body or on a portion of the first element closer to the construction machine body than the center. Furthermore, the first element or the first element and the construction machine main body considered as a rigid body, the drive link, the connecting link and the second element may form a cross-type four-bar link. Furthermore, the length from the connection position of the drive link to the construction machine body to the connection position of the connecting link may be shorter than the length from the connection position of the second element to the first element to the connection position of the connecting link. Furthermore, the length from the connection position of the second element to the first element to the connection position of the connecting link may be shorter than the length from the connection position of the connecting link to the drive link to the connection position of the second element, and the length from the connection position of the connecting link to the drive link to the connection position of the second element may be shorter than the length from the connection position of the first element to the construction machine body to the connection position of the second element. Furthermore, when the working element assumes a predetermined posture, the angle formed by the line connecting the connection position of the drive link to the construction machine body and the connection position of the connecting link and the line connecting the connection position of the connecting link to the drive link and the connection position of the second element may be 45 degrees or more and 90 degrees or less, and the angle formed by the line connecting the connection position of the connecting link to the drive link and the connection position of the second element and the line connecting the connection position of the second element to the first element and the connection position of the connecting link may be 45 degrees or more and 90 degrees or less. Also, an input rotation angle at which the drive unit rotates the drive link may be greater than an output rotation angle at which the second element rotates relative to the first element.

[0013] In addition, an expandable damper may be provided in at least one of the working element and the link mechanism. The drive device may also have an electric motor and an eccentric oscillating reducer that reduces the rotation speed of the electric motor, and an output shaft of the eccentric oscillating reducer may output the rotational force.

[0014] A drive system according to one embodiment includes a drive unit that outputs a rotational force, and a link mechanism that connects the drive unit to a working element that is rotatably connected to a construction machine body and inputs the rotational force of the drive unit to the working element. This drive system is specifically a drive system for a construction machine, and more specifically a drive system for a working element of a construction machine.

[0015] A drive device according to one embodiment includes an output shaft that outputs rotational force, and the output shaft is connected to a link mechanism that is rotatably connected to a working element that is rotatably connected to a construction machine body. This drive device is specifically a drive device for a construction machine, and more specifically a drive device for a working element of a construction machine. [Effects of the Invention]

[0016] According to the present invention, a working element rotatably connected to a construction machine body can be driven by a drive unit with a small output or while suppressing the output of the drive unit. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a side view of a construction machine according to a first embodiment of the present invention. [Figure 2] 2 is a side view of the construction machine according to the first embodiment in a state in which the working element has been rotated upward from the state shown in FIG. 1. FIG. [Figure 3] 2 is a side view of the construction machine according to the first embodiment in a state in which the working element has been rotated downward from the state shown in FIG. 1. FIG. [Figure 4] FIG. 4 is a schematic cross-sectional view of the construction machine taken along line IV-IV shown in FIG. [Figure 5] FIG. 1 is a diagram showing the geometry of a four-bar link. [Figure 6A] 3 is a side view of the construction machine according to the first embodiment in a standby position in which the working element has been rotated further upward from the state shown in FIG. 2. FIG. [Figure 6B] FIG. 10 is a side view of a construction machine according to a modified example. [Figure 7] FIG. 4 is a side view of a construction machine according to a second embodiment of the present invention. [Figure 8] FIG. 8 is a side view of the construction machine according to the second embodiment in a state where the boom is lowered and the arm is extended forward from the state shown in FIG. 7. [Figure 9] 9 is a side view of the construction machine according to the second embodiment in a state where the arm has been pulled forward from the state shown in FIG. 7, in the opposite direction to that in FIG. 8. FIG. [Figure 10] 8 is a schematic cross-sectional view of the construction machine taken along line XX shown in FIG. 7. [Figure 11] FIG. 10 is a side view of a construction machine according to a third embodiment of the present invention. [Figure 12] FIG. 10 is a side view of a construction machine according to a fourth embodiment of the present invention. [Figure 13] FIG. 10 is a side view of a construction machine according to a fifth embodiment of the present invention. [Figure 14] FIG. 10 is a diagram showing the vicinity of a drive device of a construction machine according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, each embodiment of the present invention will be described.

[0019] First Embodiment The construction machine 1 according to the first embodiment shown in Fig. 1 is a shovel. The construction machine 1 includes a construction machine body 10, a working element 20 rotatably connected to the construction machine body 10, a drive unit 30 that outputs a rotational force to drive the working element 20, and a link mechanism 40 that connects the drive unit 30 and the working element 20.

[0020] The construction machine main body 10 has a lower traveling body 11 and an upper rotating body 12. The lower traveling body 11 drives a pair of crawlers with a motor to cause the construction machine 1 to travel in the forward and backward directions. The motor used in the lower traveling body 11 may be an electric motor, a hydraulic motor, or an engine.

[0021] The upper rotating body 12 is disposed above the lower traveling body 11 and is rotatably connected to the lower traveling body 11. The upper rotating body 12 can rotate relative to the lower traveling body 11 around an axis extending in the direction in which the lower traveling body 11 and the upper rotating body 12 overlap, specifically around an axis extending in the vertical direction.

[0022] The working element 20 is rotatably connected to the upper rotating body 12 of the construction machine body 10. More specifically, the working element 20 is connected to the front portion of the upper rotating body 12. The working element is a part that performs the work expected of the construction machine, for example, by changing its posture, movement, etc. The working element is sometimes called a working device or a working unit. The construction machine body is the part that supports the working element.

[0023] The working element 20 has a boom 21, an arm 22, and a bucket 23. A base end portion of the boom 21 is rotatably connected to a front portion of the upper rotating body 12. A base end portion of the arm 22 is rotatably connected to a tip end portion of the boom 21. A base end portion of the bucket 23 is rotatably connected to a tip end portion of the arm 22.

[0024] 1 indicates an axis passing through the center of a connecting shaft that connects a base end portion of the boom 21 and a front portion of the upper rotating body 12. The boom 21 is rotatable relative to the upper rotating body 12 about the axis A1.

[0025] The boom 21 can rotate about the axis A1 by receiving the rotational force of the drive unit 30 via the link mechanism 40. When the boom 21 rotates, the entire working element 20 rotates.

[0026] Figure 2 shows a state in which the construction machine 1 has driven the boom 21 with the rotational force of the drive unit 30, causing the working element 20 to rotate upward (in the direction of the arrow CW) from the state shown in Figure 1. Figure 3 shows a state in which the construction machine 1 has driven the boom 21 with the rotational force of the drive unit 30, causing the working element 20 to rotate downward (in the direction of the arrow CCW) from the state shown in Figure 1.

[0027] The arrow CW indicates the direction of clockwise rotation about the axis A1 on the paper of Figures 1 to 3. The arrow CCW indicates the direction of counterclockwise rotation about the axis A1 on the paper of Figures 1 to 3.

[0028] 1 indicates an axis that passes through the center of a connecting shaft that connects a base end portion of the arm 22 and a tip end portion of the boom 21. The arm 22 is rotatable relative to the boom 21 around the axis A2.

[0029] The portion of the boom 21 between the connection position to the construction machine body 10 and the connection position to the arm 22 is connected to a portion of the base end of the arm 22 that is different from the position of the axis A2 by an arm cylinder 24. The arm 22 can rotate around the axis A2 in response to the extension and contraction of the arm cylinder 24. The arm cylinder 24 may be a hydraulic cylinder or an electric cylinder.

[0030] 1 indicates an axis that passes through the center of a connecting shaft that connects a base end portion of the bucket 23 and a tip end portion of the arm 22. The bucket 23 is rotatable relative to the arm 22 about the axis A3.

[0031] A portion of arm 22 on the base end side that is different from the position of axis A2 and a portion of bucket 23 on the base end side that is different from the position of axis A3 are connected by bucket cylinder 25. Bucket 23 can rotate about axis A3 in response to extension and contraction of bucket cylinder 25. Note that bucket cylinder 25 may be a hydraulic cylinder or an electric cylinder.

[0032] The drive unit 30 is provided on the upper revolving body 12 of the construction machine body 10. Specifically, the drive unit 30 shown in Fig. 1 is provided on the upper revolving body 12 at a position rearward and above the position of the axis A1.

[0033] FIG. 4 is a schematic cross-sectional view of the construction machine 1 taken along line IV-IV shown in FIG. 1, and is a diagram illustrating the positional configuration and connection configuration of the working element 20 and the drive device 30 in the construction machine 1.

[0034] As shown in Fig. 4, the drive unit 30 has an electric motor 31 and a reducer 32. The electric motor 31 and the reducer 32 are supported by a support plate 12A that extends upward and is part of the upper rotating body 12, and are positioned so as to face each other in the thickness direction of the support plate 12A with the support plate 12A in between. The support plate 12A is formed by a side wall that is part of the upper rotating body main body 120 (construction machine main body 10) of the upper rotating body 12. The electric motor 31 is located inside the upper rotating body main body 120, and is covered from above by the upper wall portion 12R of the upper rotating body main body 120.

[0035] The electric motor 31 has a rotary shaft 31A, which extends parallel to an axis A1 of a connecting shaft portion that connects the base end portion of the boom 21 and the front portion of the upper rotating body 12. Symbol A4 in Figures 1 and 4 indicates an axis that passes through the center of the rotary shaft 31A, and the rotary shaft 31A rotates around the axis A4. The electric motor 31 may be a DC motor or an AC motor.

[0036] The reducer 32 has an input shaft 32A coaxially connected to the rotary shaft 31A, and an output shaft 32B that outputs a rotational speed obtained by reducing the rotational speed transmitted from the rotary shaft 31A to the input shaft 32A at a predetermined reduction ratio. In other words, the output shaft 32B outputs the rotational force of the drive unit 30.

[0037] 4 is an eccentric oscillating reducer. In this case, in the reducer 32, the rotation of the input shaft 32A, which is rotated by the rotary shaft 31A, is transmitted to the crankshaft 32D via the transmission gear 32C, which is disposed on the outer periphery of the input shaft 32A. The crankshaft 32D oscillates the external gear 32E that it supports, thereby rotating the external gear 32E relative to the internal gear 32F, which is disposed on the outer periphery of the external gear 32E.

[0038] 4, the internal gear 32F is fixed to the construction machine body 10 (support plate 12A), so the external gear 32E rotates relative to the internal gear 32F and the construction machine body 10. Then, the output shaft 32B, also known as a carrier, rotates around the axis A4, supporting the oscillating motion of the external gear 32E.

[0039] The internal gear 32F is cylindrical, has internal teeth on its inner circumferential surface, and has a flange portion 32FA on its outer circumferential surface. The reducer 32 is fixed to the support plate 12A by fastening a fastening member 300, such as a bolt, through the flange portion 32FA. A first seal 121, such as an O-ring, is provided between the flange portion 32FA and the support plate 12A. The first seal 121 is housed in a groove formed in the support plate 12A, but may also be housed in a groove formed in the flange portion 32FA. The first seal 121 is disposed radially inward of the fastening member 300. The support plate 12A is also provided with a plate recess 12A1. The support plate 12A supports the reducer 32 with a portion of the reducer 32 housed in the plate recess 12A1. The end of the output shaft 32B on the support plate 12A side and the end of the internal gear 32F are housed in the plate recess 12A1. The electric motor 31 has a cylindrical case with a flange 31F on the outer circumferential surface of the case. The electric motor 31 is fixed by fastening fastening members such as bolts passed through the flange 31F to the support plate 12A. A second seal 122 such as an O-ring is provided between the flange 31F and the support plate 12A. The second seal 122 is housed in a groove formed in the support plate 12A, but may also be housed in a groove formed in the flange 31F.

[0040] In an eccentric oscillating reducer, speed reduction occurs between the input shaft 32A and the transmission gear 32C and between the crankshaft 32D and the external gear 32E, enabling a high reduction ratio and high torque output. Furthermore, a large contact area between the tooth surfaces of the external gear 32E and the internal gear 32F can be ensured, ensuring high durability and reliability. Figure 4 shows an eccentric oscillating reducer configured with multiple crankshafts 32D arranged circumferentially. However, it goes without saying that the eccentric oscillating reducer used as the reducer 32 may be a center crank type in which the crankshaft is coaxial with the rotation axis of the external gear. The reducer 32 may also be of another type.

[0041] As shown in FIGS. 1 and 4, the link mechanism 40 has a drive link 41 and a connecting link 42, and the drive link 41 and the connecting link 42 connect the drive device 30 and the boom 21 together.

[0042] One of the two ends of the drive link 41 is connected to the output shaft 32B of the reducer 32. In other words, the drive link 41 is directly connected to the drive device 30. The other of the two ends of the drive link 41 is connected to the connecting link 42. The drive link 41 rotates about the axis A4 as the output shaft 32B of the reducer 32 rotates. As shown in FIG. 4 , a link recess 41A is provided in the drive link 41, and the drive link 41 is connected to the output shaft 32B with a part of the reducer 32 housed in the link recess 41A. The end of the output shaft 32B on the drive link 41 side and the end of the internal gear 32F are housed in the link recess 41A.

[0043] On the other hand, one of the two ends of the connecting link 42 is rotatably connected to the other end of the drive link 41. One end of the connecting link 42 is connected to the drive link 41 in a state where it overlaps the face of the drive link 41 on the side where the drive link 41 is connected to the output shaft 32B. This makes it possible to reduce the area occupied by the drive unit 30 and the link mechanism 40. In addition, the other end of the connecting link 42 is rotatably connected to a portion of the boom 21 between the connection position of the boom 21 to the construction machine body 10 and the connection position of the boom 21 to the arm 22.

[0044] 1 and 4, the symbol A5 indicates an axis that passes through the center of the connecting shaft that connects the driving link 41 and the connecting link 42. The connecting link 42 is rotatable relative to the driving link 41 about the axis A5.

[0045] 1 and 4, the reference symbol A6 indicates an axis that passes through the center of the connecting shaft that connects the connecting link 42 and the boom 21. The connecting link 42 is rotatable relative to the boom 21 about the axis A6.

[0046] In this embodiment, as shown in Fig. 1, the drive link 41, the connecting link 42, the boom 21, and the upper rotating body 12 form a four-bar link (more specifically, a non-parallel four-bar link). In this case, when the drive unit 30 rotates the drive link 41 clockwise in Fig. 1 around the axis A4, the boom 21 rotates clockwise as indicated by the arrow CW around the axis A1 as shown in Fig. 2. When the drive unit 30 rotates the drive link 41 counterclockwise in Fig. 1 around the axis A4, the boom 21 rotates counterclockwise as indicated by the arrow CCW around the axis A1 as shown in Fig. 3.

[0047] Referring to Figure 1, in the four-bar link formed by the construction machine 1 of this embodiment, the length B from the connection position of the drive link 41 to the construction machine body 10 (position on axis A4) to the connection position of the connecting link 42 (position on axis A5) is shorter than the length D from the connection position of the boom 21 to the construction machine body 10 (position on axis A1) to the connection position of the connecting link 42 (position on axis A6).

[0048] FIG. 5 is a diagram showing the geometry of a four-bar link, and is a diagram for explaining the relationship between link length and input / output torque in a four-bar link. The symbols A, B, C, and D shown in FIG. 5 respectively indicate the lengths of the four links. Symbol L indicates a diagonal line connecting the connection point of a link of length B and a link of length C to the connection point of a link of length A and a link of length D. α1, α2, α3, and α4 respectively indicate the angles when the diagonal line divides the interior angle. Also, T i indicates the input torque when a link of length B is rotated around the connection point with a link of length A, and T O is the input T i indicates the output torque when a link of length D rotates around its connection point with a link of length A.

[0049] For a four-bar link, the following mathematical relationship holds true:

[0050]

number

[0051] The above formula shows that when length B is smaller than length D, the output torque T O is the input torque T i This indicates that the output torque of the boom 21, which is rotated by the input torque output by the drive link 41, is greater than the input torque. Taking this relationship into consideration, in this embodiment, the length B from the connection position of the drive link 41 to the connection position of the connecting link 42 is made shorter than the length D from the connection position of the boom 21 to the connection position of the connecting link 42, as described above, so that the output torque of the boom 21, which is rotated by the input torque output by the drive link 41, is greater than the input torque. This allows the working element 20 to efficiently apply force to a work target, such as the ground, on which the working element 20 works.

[0052] Furthermore, in this embodiment, while the above-mentioned relationship that length B of the drive link 41 is smaller than length D of the boom 21 holds, a relationship also holds that the input rotation angle at which the drive unit 30 rotates the drive link 41 is greater than the output rotation angle at which the boom 21 rotates relative to the construction machine body 10. In other words, this means that the rotation at the time of input is decelerated, and the output torque is greater than the input torque. Even when this relationship holds, force can be efficiently applied from the working element 20 to the work target.

[0053] 2, symbol L1 indicates a straight line connecting the connection position of the drive link 41 to the construction machine body 10 (position of axis A4) and the connection position of the connecting link 42 (position of axis A5). Symbol L2 indicates a straight line connecting the connection position of the connecting link 42 to the drive link 41 (position of axis A5) and the connection position of the boom 21 (position of axis A6). Symbol L3 indicates a straight line connecting the connection position of the boom 21 to the construction machine body 10 (position of axis A1) and the connection position of the connecting link 42 (position of axis A6).

[0054] As shown in FIG. 2, in this embodiment, when the boom 21 is rotated upward, the angle X between the lines L1 and L2 is between 45 degrees and 90 degrees, and the angle Y between the lines L2 and L3 is between 45 degrees and 90 degrees. Specifically, when the angle X is approximately 50 degrees, the angle Y is approximately 70 degrees. With this relationship, the force of the drive link 41 is efficiently transmitted to the boom 21. Note that the angles X and Y are interior angles.

[0055] When scraping away earth and sand with the bucket 23 and then rotating the working element 20 upward to move it to the bed of a truck, the load on the boom 21 may become large. Taking such a situation into consideration, in this embodiment, the above relationship is determined when the boom 21 is in a position rotated upward, but the position of the working element 20 that establishes this relationship may be determined arbitrarily depending on the work content.

[0056] In addition, with regard to the relationship between the angles X and Y, when the angle X is 67.5 degrees or more and 90 degrees or less, it is more preferable that the angle Y is 67.5 degrees or more and 90 degrees or less, and when the angle X is 75 degrees or more and 90 degrees or less, it is even more preferable that the angle Y is 75 degrees or more and 90 degrees or less.

[0057] Furthermore, the shape of the four-bar link formed by the drive link 41, connecting link 42, boom 21, and upper rotating body 12 is not particularly limited, and may be a parallel four-bar link or a cross-type four-bar link. Furthermore, the drive link 41 and connecting link 42 are detachable from each other and from the construction machine main body 10 or the boom 21. This allows the drive link 41 and connecting link 42 to be changed to different shapes as needed, making it possible to adjust the range of movement, acceleration / deceleration, and power multiplication ratio as needed. In this embodiment, the link with length B in FIG. 5 corresponds to the drive link 41, and the link with length D in FIG. 5 corresponds to the boom 21. However, the lengths of the four-bar link formed by the drive link 41, connecting link 42, boom 21, and upper rotating body 12 are not particularly limited. For example, a configuration in which the link with length B in FIG. 5 corresponds to the connecting link 42, or a configuration in which the link with length C in FIG. 5 corresponds to the drive link 41, may be adopted. 1 to 3, the lengths of the drive link 41, the connecting link 42, etc. are exaggerated and differ from the actual lengths. The drive device 30 and the link mechanism 40 constitute a drive system.

[0058] 6A is a side view of the construction machine 1 in a standby position where the working element 20 has been further rotated upward from the state shown in FIG. 2. Specifically, the boom 21 has reached the boom standby position by rotating further upward from the state shown in FIG. 2. The arm 22 has reached the arm standby position by rotating downward in a counterclockwise direction from the state shown in FIG. 2. The boom standby position is the rotation limit position of the boom 21 in the clockwise direction on the page. The arm standby position is the rotation limit position of the arm 22 in the counterclockwise direction on the page. The standby position is formed when the boom 21 reaches the boom standby position and the arm 22 reaches the arm standby position.

[0059] As shown in Fig. 6A, when the boom 21 reaches the boom standby position, the drive link 41, which rotates clockwise on the page, comes into contact with a stopper portion 12S provided on the upper rotating body 12 of the construction machine main body 10, and its rotation is restricted. With reference to Figs. 1 to 4, the stopper portion 12S is provided behind the drive unit 30 provided on the support plate 12A of the upper rotating body 12 (see Fig. 4).

[0060] The stopper portion 12S shown in the figure forms a contact surface that extends horizontally, and this contact surface comes into contact with the drive link 41. However, the contact surface of the stopper portion 12S can extend vertically or at an angle depending on the rotation limit position of the boom 21, which is determined arbitrarily.

[0061] In FIG. 6A, the symbol Gp indicates the center of gravity of the working element 20 in the standby position. The symbol V indicates a vertical line extending vertically from the axis A1, which is the center of rotation of the boom 21. In the standby position shown in FIG. 6A, the center of gravity Gp of the working element 20 is behind the vertical line V and above the axis A1. In this case, the working element 20 attempts to rotate clockwise on the page. Here, in this embodiment, the rotation is restricted by the drive link 41 coming into contact with the stopper portion 12S.

[0062] 1 to 3 and 6A also show the locking member 12L for the working element 20 in the standby position. FIG. 6A shows area T when viewed in the direction of arrow VIA in the same figure. Referring to area T, when the working element 20 in the standby position is not locked, the locking member 12L extends in the front-to-rear direction along the side wall of the upper rotating body 12, as indicated by the dashed line. When the working element 20 in the standby position is locked, the locking member 12L rotates in the width direction around its rear portion. The locking member 12L overlaps with the drive link 41 above the drive link 41 connected to the working element 20 in the standby position. This also limits the counterclockwise rotation of the drive link 41 as viewed in the drawing. The stopper 12S and locking member 12L described above enable safe storage of the construction machine 1 with the working element 20 in the standby position. More specifically, the working element 20 is in a standby position, and when the power is turned off, the working element 20 does not rotate forward or backward.

[0063] Figure 6B shows a modified example of the construction machine 1. In the modified example of Figure 6B, the configuration of the locking member 12L differs from that of Figure 6A. The locking member 12L shown in Figure 6B is a columnar member. This locking member 12L is fitted into the side wall of the upper rotating body 12 so as to be located above the drive link 41 connected to the working element 20 in the standby position.

[0064] Next, the operation of the construction machine 1 according to this embodiment will be described.

[0065] When the boom 21 is rotated, the rotational force of the drive device 30 is input to the boom 21 via the link mechanism 40. As a result, the boom 21 rotates about the axis A1.

[0066] Specifically, when the drive unit 30 rotates the drive link 41 clockwise in Fig. 1 around the axis A4, the boom 21 rotates clockwise as indicated by the arrow CW around the axis A1 as shown in Fig. 2. When the drive unit 30 rotates the drive link 41 counterclockwise in Fig. 1 around the axis A4, the boom 21 rotates counterclockwise as indicated by the arrow CCW around the axis A1 as shown in Fig. 3.

[0067] In this embodiment, the rotational force of the drive unit 30 is converted by the link mechanism 40 into a unidirectional force that acts on the boom 21. This force acting on the boom 21 is applied at a position away from the rotation axis (connection shaft portion where axis A1 is located) of the boom 21 on the construction machine body 10 side. This ensures a sufficient distance between axis A1, which is the center of rotation of the boom 21, and the point of application of the force, and even in the case of a drive unit 30 with a low output or when the output of the drive unit 30 is reduced, it is possible to ensure a large torque input to the boom 21, making it possible to rotate the boom 21 easily.

[0068] Therefore, according to the construction machine 1 of this embodiment, the working element 20 can be driven by a drive unit 30 with a small output or while suppressing the output of the drive unit 30. Specifically, for example, even if the drive unit 30 uses an electric motor and it is difficult to ensure a larger output than a general hydraulic motor, the working element 20 can be driven in a manner that compares favorably with a hydraulic motor.

[0069] Furthermore, in this embodiment, the drive unit 30 is provided on the construction machine body 10, and the link mechanism 40 has a drive link 41 that is directly connected to the drive unit 30, and a connecting link 42 that connects the drive link 41 and the boom 21. As a result, the drive link 41, connecting link 42, boom 21, and construction machine body 10 form a four-joint link, and the boom 21 rotates as the drive link 41 rotates relative to the construction machine body 10, without complicating the structure. This makes it possible to avoid the construction machine 1 becoming excessively complex, heavy, and large.

[0070] Furthermore, in this embodiment, the drive unit 30 is located rearward of the connection position between the boom 21 and the construction machine body 10. This prevents the center of gravity of the construction machine 1 from being shifted forward, thereby achieving a good weight balance.

[0071] Furthermore, the length B from the connection position of the drive link 41 to the construction machine body 10 to the connection position of the connecting link 42 is shorter than the length D from the connection position of the boom 21 to the connection position of the connecting link 42 to the connection position of the boom 21 to the connection position of the connecting link 42. In this configuration, the rotational force (torque) of the boom 21 rotating around the construction machine body 10 is greater than the rotational force (torque) of the drive link 41 rotating around the drive unit 30. This allows the working element 20 to efficiently apply force to the work target.

[0072] Furthermore, in the construction machine 1, when the working element 20 assumes a predetermined posture, specifically when the boom 21 is rotated upward, the angle between the lines L1 and L2 is between 45 degrees and 90 degrees, and the angle between the lines L2 and L3 is between 45 degrees and 90 degrees, as shown in Figure 2. This allows the rotational force of the drive unit 30 to be efficiently transmitted to the boom 21.

[0073] <Second embodiment> Next, a construction machine 2 according to a second embodiment will be described.

[0074] FIG. 7 is a side view of the construction machine 2. FIG. 8 shows the construction machine 2 in a state in which the boom 21 has been lowered from the state shown in FIG. 7 and the arm 22 has been extended forward (away from the construction machine body). FIG. 9 shows the construction machine 2 in a state in which the arm 22 has been pulled forward (toward the construction machine body), opposite to the state in FIG. 8, from the state shown in FIG. 7. FIG. 10 is a schematic cross-sectional view of the construction machine 2 taken along line XX shown in FIG. 7, and shows the positional configuration and connection configuration of the working element 20 and the drive unit 30 in the construction machine 2. Components in this embodiment that are the same as those in the first embodiment are given the same reference numerals, and description thereof will be omitted.

[0075] In this embodiment, the connecting link 42 in the link mechanism 40 is connected to the arm 22 of the working element 20 .

[0076] The drive unit 30 is provided on the construction machine body 10, and one of the two ends of the drive link 41 is connected to the output shaft 32B of the reducer 32 in the drive unit 30. The other of the two ends of the drive link 41 is rotatably connected to one of the two ends of the connecting link 42. The other of the two ends of the connecting link 42 is rotatably connected to the arm 22.

[0077] More specifically, the other end of the connecting link 42 is connected to a portion between the connection position of the arm 22 to the boom 21 (position of the axis A2) and the connection position of the arm 22 to the bucket 23 (position of the axis A3).

[0078] 7 to 9, the symbol A6' indicates an axis passing through the center of the connecting shaft portion that connects the connecting link 42 and the arm 22. In this embodiment, the boom 21 corresponds to the first element, and the arm 22 corresponds to the second element.

[0079] In this embodiment, the upper rotating body 12 is provided with a boom drive device 50. As shown in Fig. 10, the boom drive device 50 has a boom electric motor 51 and a boom reducer 52. The boom electric motor 51 and the boom reducer 52 are supported by a boom support plate 12B that is part of the upper rotating body 12 and extends upward.

[0080] The rotation shaft of the boom electric motor 51 and the output shaft of the boom reducer 52 are positioned coaxially, and axis A1 is positioned straddling the central axes of the rotation shaft and output shaft. In this embodiment, the drive unit 30 and the boom drive unit 50 are arranged so that axis A1, which is the rotation center of the boom 21, and axis A4, which is the rotation center of the drive link 41 on the construction machine body 10 side, are coaxial. However, the drive unit 30 and the boom drive unit 50 are not rotationally connected, and each is driven independently.

[0081] Boom reducer 52 in this embodiment is configured as an eccentric oscillating reducer, similar to reducer 32. Although a detailed description of the structure of boom reducer 52 will be omitted, boom reducer 52 has a base end side portion of boom 21 fixed to its output shaft. That is, in this embodiment, boom 21 is directly rotated by boom drive device 50.

[0082] In this embodiment, by connecting the drive unit 30 and the arm 22 via the link mechanism 40 as described above, the drive link 41, the connecting link 42, the arm 22, and the boom 21 and the construction machine body 10, which are considered to be rigid bodies, form a cross-type four-bar link, as shown in FIG. 7.

[0083] In this case, when the driving device 30 rotates the driving link 41 counterclockwise in Fig. 7 about the axis A4 from the state in Fig. 7, the arm 22 rotates clockwise in Fig. 7 about the axis A2 as shown by the arrow CW, as shown in Fig. 8. Also, when the driving device 30 rotates the driving link 41 clockwise in Fig. 7 about the axis A4 from the state in Fig. 7, the arm 22 rotates counterclockwise in Fig. 7 about the axis A2 as shown by the arrow CCW, as shown in Fig. 9.

[0084] Furthermore, in this embodiment, as shown in FIG. 7, the length B from the connection position of the drive link 41 to the construction machine body 10 (position on axis A4) to the connection position of the connecting link 42 (position on axis A5) is shorter than the length D from the connection position of the arm 22 to the boom 21 (position on axis A2) to the connection position of the connecting link 42 (position on axis A6').

[0085] That is, in this embodiment, length B is made shorter than length D so that the output torque output by the arm 22, which rotates due to the input torque output by the drive link 41, is greater than the input torque. At the same time as this relationship, there is also a relationship that the input rotation angle at which the drive unit 30 rotates the drive link 41 is greater than the output rotation angle at which the arm 22 rotates relative to the construction machine body 10.

[0086] Further, to explain the lengths of the parts that make up the four-bar link in more detail, the length D of the arm 22 is shorter than the length C from the connection position of the connecting link 42 to the drive link 41 (position on axis A5) to the connection position of the arm 22 (position on axis A6'). The length C of the connecting link 42 is shorter than the length D from the connection position of the boom 21 to the construction machine body 10 (position on axis A1) to the connection position of the arm 22 (position on axis A2). After extensive research, the inventors of the present invention found that when the arm 22 of the shovel is driven by the link mechanism 40, this length relationship allows for a force to be suitably applied to the work target.

[0087] 7, in this embodiment, when the arm 22 is oriented generally in the vertical direction, angle X' is 45 degrees or more and 90 degrees or less, and angle Y' is 45 degrees or more and 90 degrees or less. Angle X' is the angle (interior angle) formed by a line connecting the connection position of the drive link 41 to the construction machine body 10 and the connection position of the connecting link 42, and a line connecting the connection position of the connecting link 42 to the drive link 41 and the connection position of the arm 22. Angle Y' is the angle formed by a line connecting the connection position of the connecting link 42 to the drive link 41 and the connection position of the arm 22, and a line connecting the connection position of the arm 22 to the boom 21 and the connection position of the connecting link 42.

[0088] When scraping away earth and sand with bucket 23, the load on arm 22 may become large. In this embodiment, the above relationship is determined taking such a situation into consideration, but the posture of working element 20 that satisfies the above relationship may be determined arbitrarily depending on the work content.

[0089] In addition, with regard to the relationship between the angles X' and Y', when the angle X' is 67.5 degrees or more and 90 degrees or less, it is more preferable that the angle Y' is 67.5 degrees or more and 90 degrees or less, and when the angle X' is 75 degrees or more and 90 degrees or less, it is even more preferable that the angle Y' is 75 degrees or more and 90 degrees or less.

[0090] Furthermore, the shape of the four-bar link formed by the drive link 41, connecting link 42, boom 21, and upper rotating body 12 is not particularly limited, and may be a parallel four-bar link or a non-intersecting non-parallel four-bar link.

[0091] Furthermore, in this embodiment, the drive unit 30 is provided on the construction machine body 10, but the drive unit 30 may also be provided on the boom 21. In this case, in consideration of weight balance, the drive unit 30 is preferably provided on a portion of the boom 21 closer to the construction machine body 10 than the center.

[0092] In the third embodiment described above, the link mechanism 40 converts the rotational force of the drive unit 30 into a unidirectional force acting on the arm 22. Then, this force acting on the arm 22 is applied at a position away from the rotation axis (the connection axis portion where the axis A2 is located) of the arm 22 on the boom 21 side. This ensures a sufficient distance between the axis A2, which is the center of rotation of the arm 22, and the point of application of the force. Therefore, even in the case of a drive unit 30 with a small output or when the output of the drive unit 30 is reduced, it is possible to ensure a large torque input to the arm 22, and it becomes possible to rotate the arm 22 easily.

[0093] Therefore, according to the construction machine 3 of this embodiment, the work element 20 can be driven by a drive unit 30 with a small output or while suppressing the output of the drive unit 30.

[0094] Furthermore, by using the link mechanism 40, the arm can be driven by a drive unit 30 located away from the arm 22, thereby improving the degree of freedom in the placement of the drive unit 30. In this embodiment, the drive unit 30 that drives the arm 22 is provided on the construction machine body 10, so heavy objects can be brought closer to the center of gravity of the construction machine 3, achieving good weight balance.

[0095] Furthermore, in this embodiment, by providing the drive unit 30 to the construction machine body 10, the boom 21 and construction machine body 10 are regarded as rigid bodies, and the drive link 41, connecting link 42, and arm 22 form a four-bar link, which allows the arm 22 to rotate as the drive link 41 rotates without complicating the structure. The above four-bar link is a cross-type four-bar link. This allows the link mechanism and the working element to partially cross each other, thereby reducing the area occupied by the components.

[0096] <Third embodiment> Next, a construction machine 3 according to a third embodiment will be described. Fig. 11 is a side view of the construction machine 3. Of the components in this embodiment, the same components as those in the first and second embodiments will be given the same reference numerals, and their description will be omitted.

[0097] In this embodiment, the bucket drive device 60 provided on the arm 22 and the bucket 23 are connected by a bucket link mechanism 400. Like the drive device 30 described above, the bucket drive device 60 has an electric motor and a reducer. The bucket link mechanism 400 has a bucket drive link 401 that is directly connected to the bucket drive device 60, and a bucket connection link 402 that connects the bucket drive link 401 and the bucket 23. The other configurations are the same as those in the second embodiment.

[0098] With the construction machine 3 according to this embodiment, the bucket 23 can be driven by a bucket driving device 60 with a low output, or while suppressing the output of the bucket driving device 60. Furthermore, in this embodiment, the bucket driving device 60 is provided on the arm 22 closer to the connection between the arm 22 and the boom 21 than to the connection between the bucket 23 and the arm 22, while the driving device 30 and the boom driving device 50 are provided on the construction machine main body 10. This makes it possible to prevent the center of gravity of the construction machine 3 from being positioned too far forward, achieving a good weight balance.

[0099] <Fourth embodiment> Next, a construction machine 4 according to a fourth embodiment will be described. Fig. 12 is a side view of the construction machine 4. Of the components in this embodiment, the same components as those in the first to third embodiments will be given the same reference numerals, and their description will be omitted.

[0100] In this embodiment, an expandable damper 44 is provided on the connecting link 42 of the link mechanism 40. When a compressive force of a predetermined value or more is applied to the connecting link 42, the damper 44 discharges oil filled therein through a relief valve 45, thereby compressing the connecting link 42. The configuration of the damper 44 is not particularly limited. The other configurations are the same as those of the third embodiment.

[0101] In the construction machine 4 according to the fourth embodiment, the compressive force acting on the working element 20 is released through the damper 44 before being transmitted to the driving device 30, thereby protecting the driving device 30, and in particular the tooth surface of the reducer 32. When the connecting link 42 is connected to the arm 22, a compressive force is applied to the connecting link 42 due to a reaction force applied to the bucket 23 from a work object such as the ground, which may increase the load on the reducer 32. In consideration of this, in this embodiment, the connecting link 42 is provided with the damper 44. The damper 44 may be provided on the working element 20 or on the drive link 41.

[0102] <Fifth embodiment> Next, a construction machine 5 according to a fifth embodiment will be described. Fig. 13 is a side view of the construction machine 5. Of the components in this embodiment, the same components as those in the first to fourth embodiments will be given the same reference numerals, and their description will be omitted.

[0103] The construction machine 5 according to this embodiment is a bulldozer, and the working element 20 connected to the construction machine body 10 has a lift arm 26 rotatably supported directly on the construction machine body 10, and a blade 27 rotatably connected to the lift arm 26. A drive unit 30 is provided on the construction machine body 10, and a link mechanism 40 has a drive link 41 connected to the drive unit 30, and a connecting link 42 that connects the drive link 41 and the lift arm 26.

[0104] In the construction machine 5 according to this embodiment, the lift arm 26 can be moved up and down by rotating the drive link 41 with the drive unit 30. As exemplified in this embodiment, the link mechanism 40 can also be applied to various construction machines other than shovels.

[0105] The aspects of the present invention are not limited to the individual embodiments described above, but include various modifications that may be conceived by those skilled in the art, and the effects of the present invention are not limited to the above. In other words, various additions, modifications, and partial deletions are possible within the scope of the conceptual idea and spirit of the present invention as derived from the content defined in the claims and their equivalents. Among the embodiments disclosed in this specification, those consisting of multiple objects may be integrated, and conversely, a single object may be divided into multiple objects. Regardless of whether they are integrated, it is sufficient that the object of the invention can be achieved.

[0106] For example, in the first embodiment, the electric motor 31 and the reducer 32 of the drive unit 30 are arranged to face each other in the thickness direction of the support plate 12A, with the support plate 12A sandwiched therebetween. Alternatively, as shown in a modified example in FIG. 14 , the electric motor 31 and the reducer 32 may be supported on one side of the support plate 12A. The electric motor 31 and the reducer 32 may be arranged inside the upper rotating body main body 120 of the upper rotating body 12 and covered by the upper rotating body main body 120. In FIG. 14 , a fastening member 300 is passed between the support plate 12A and a flange portion 32FA on the outer periphery of the internal gear of the reducer 32. Furthermore, the fastening member 300 extends from the flange portion 32FA side and is fastened to a motor mounting base 301. The motor mounting base 301 is cylindrical and supports the electric motor 31 at the end opposite to the flange portion 32FA side. 14, the electric motor 31 may be supported on a motor mounting base 301 fixed to the output shaft 32B. In the embodiment shown in FIGS. 1 to 12 above, the working element 20 is attached to the side of the construction machine body 10. However, the attachment position of the working element 20 is not particularly limited. The working element 20 may be attached to the center of the front of the construction machine body 10, for example. [Explanation of symbols]

[0107] 1, 2, 3, 4, 5...construction machine, 10...construction machine body, 11...undercarriage, 12...upper rotating body, 120...upper rotating body body, 121...first seal material, 122...second seal material, 12A...support plate, 12A1...plate recess, 12B...boom support plate, 12R...upper wall portion, 12S...stopper portion, 12L...locking member, 20...working element, 21...boom, 22...arm, 23...bucket, 24...arm cylinder, 25...bucket cylinder, 26...lift arm, 27...blade, 30...drive device, 31...electric motor, 31A...rotating shaft, 31F...flange portion, 32...reduction gear, 32A...input shaft, 3 2B...output shaft, 32C...transmission gear, 32D...crankshaft, 32E...external gear, 32F...internal gear, 32FA...flange portion, 300...fastening member, 301...motor mounting base, 40...link mechanism, 41...driving link, 41A...link recess, 42...connecting link, 42A...recess, 42B...locking portion, 42C...mating member, 400...bucket link mechanism, 401...bucket driving link, 402...bucket connecting link, 44...damper, 50...boom drive device, 51...boom electric motor, 52...boom reducer, 60...bucket drive device, A1, A2, A3, A4, A5, A6, A6'...axis line

Claims

1. a working element rotatably connected to the construction machine body; a drive unit that outputs a rotational force; a link mechanism that connects the drive device and the working element and inputs a rotational force of the drive device to the working element, The working element includes a first element that is directly rotatably connected to the construction machine body, and a second element that is rotatably connected to the first element at a position different from a connection position between the construction machine body and the first element, the link mechanism includes a drive link directly connected to the drive device and a connecting link connecting the drive link and the second element, the drive device is provided on a portion of the first element closer to the construction machine body than the center or on the construction machine body, A construction machine in which the first element or the first element and the construction machine main body are considered to be rigid bodies, the drive link, the connecting link, and the second element form a cross-type four-bar link.

2. 2. The construction machine according to claim 1, wherein a length from a connection position of the drive link to the construction machine body to a connection position of the connecting link is shorter than a length from a connection position of the second element to the first element to a connection position of the connecting link.

3. a length from a connection position of the second element to the first element to a connection position of the connecting link is shorter than a length from a connection position of the connecting link to the drive link to a connection position of the second element, 3. The construction machine according to claim 2, wherein the length from the connection position of the connecting link to the drive link to the connection position of the second element is shorter than the length from the connection position of the first element to the construction machine body to the connection position of the second element.

4. 4. A construction machine according to claim 1, wherein, when the working element is in a predetermined posture, an angle formed by a straight line connecting the connection position of the drive link to the construction machine main body and the connection position of the connecting link and a straight line connecting the connection position of the connecting link to the drive link and the connection position of the second element is between 45 degrees and 90 degrees, and an angle formed by the straight line connecting the connection position of the connecting link to the drive link and the connection position of the second element and a straight line connecting the connection position of the second element to the first element and the connection position of the connecting link is between 45 degrees and 90 degrees.

5. 5. The construction machine according to claim 1, wherein an input rotation angle at which the drive unit rotates the drive link is larger than an output rotation angle at which the second element rotates relative to the first element.

6. 6. The construction machine according to claim 1, wherein an expandable damper is provided in at least one of the working element and the link mechanism.

7. 7. The construction machine according to claim 1, wherein the drive device includes an electric motor and an eccentric oscillating reducer that reduces the rotation of the electric motor, and an output shaft of the eccentric oscillating reducer outputs the rotational force.

Images