Working machinery

Abstract

The present invention provides a work machine in which the output unit, including the electric motor, is positioned further away from the road surface. [Solution] The work machine 100 includes a traveling body 200 that can be driven by drive wheels 203. The drive wheels 203 are mounted on a side frame 2012. The side frame 2012 is connected to the lower side of a center frame 2011. The work machine 100 has an output unit 1 and a transmission mechanism 3. The output unit 1 is supported by the center frame 2011 and outputs the driving force of an electric motor 11. The transmission mechanism 3 transmits the driving force from the output unit 1 to the drive wheels 203. The transmission mechanism 3 has a transmission shaft 33. The transmission shaft 33 extends downward from the output unit 1 side toward the drive wheels 203 side.

Description

[[Technical Field]]

[0001] The present invention relates to a work machine. [[Background Art]]

[0002] Conventionally, as disclosed in Patent Document 1, a swing-type construction machine is known that includes a lower traveling structure on which a traveling electric motor for rotationally driving a drive wheel is mounted coaxially with the drive wheel. [[Prior Art Documents]] [[Patent Documents]]

[0003] [[Patent Document 1]] Japanese Patent Laid-Open No. 2014-163190 [[Summary of the Invention]] [[Problem to be Solved by the Invention]]

[0004] However, when rotating a drive wheel by an electric motor, it is necessary to use a speed reducer in combination that increases the driving force (rotational force) of the electric motor. Therefore, compared to conventionally used hydraulic traveling motors, a drive system using an electric motor has a larger size, which increases the risk of damage caused by earth, sand, stones, rocks and the like. Furthermore, since the electric motor is positioned closer to the road surface, the possibility of damage to the electric motor becomes higher.

[0005] In view of the above situation, an object of the present invention is to provide a work machine in which an output unit including an electric motor is arranged at a position further away from the road surface. [[Means for Solving the Problem]]

[0006] To achieve the above objective, a work machine according to one aspect of the present invention comprises a traveling body that can be driven by drive wheels. The drive wheels are mounted on side frames. The side frames are connected to the lower sides of a center frame. The work machine has an output unit and a transmission mechanism. The output unit is supported by the center frame and outputs the driving force of an electric motor. The transmission mechanism transmits the driving force from the output unit to the drive wheel side. The transmission mechanism has a transmission shaft. The transmission shaft extends downward from the output unit side toward the drive wheel side.

[0007] Further features and advantages of the present invention will be further revealed by the embodiments described below. [Effects of the Invention]

[0008] The present invention can provide a work machine in which the output unit, including an electric motor, is positioned further away from the road surface. [Brief explanation of the drawing]

[0009] [Figure 1] A schematic side view showing an example configuration of a hydraulic excavator according to this embodiment. [Figure 2] A schematic block diagram showing the configuration of the hydraulic system and other components of a hydraulic excavator. [Figure 3] A top view showing a schematic example of the lower running body configuration. [Figure 4] Rear view showing an example of the drive unit configuration in the first embodiment. [Figure 5] Rear view showing another configuration example of the drive unit in the first embodiment. [Figure 6A] Schematic diagram showing a first configuration example of the output unit in the first embodiment. [Figure 6B] Schematic diagram showing a second configuration example of the output unit in the first embodiment. [Figure 6C] Schematic diagram showing a third configuration example of the output unit in the first embodiment. [Figure 6D] Schematic diagram showing a fourth configuration example of the output unit in the first embodiment. [Figure 6E]Schematic diagram showing the fifth configuration example of the output unit in the first embodiment [Figure 7A] Schematic diagram showing the first configuration example of the drive unit [Figure 7B] Schematic diagram showing the second configuration example of the drive unit [Figure 7C] Schematic diagram showing the third configuration example of the drive unit [Figure 7D] Schematic diagram showing the fourth configuration example of the drive unit [Figure 7E] Schematic diagram showing the fifth configuration example of the drive unit [Figure 8] Rear view showing a configuration example of the drive unit in the second embodiment [Figure 9] Rear view showing another configuration example of the drive unit in the second embodiment [Figure 10A] Schematic diagram showing the first configuration example of the output unit in the second embodiment [Figure 10B] Schematic diagram showing the second configuration example of the output unit in the second embodiment [Figure 10C] Schematic diagram showing the third configuration example of the output unit in the second embodiment [Figure 10D] Schematic diagram showing the fourth configuration example of the output unit in the second embodiment [Figure 10E] Schematic diagram showing the fifth configuration example of the output unit in the second embodiment [Figure 11] Rear view showing a configuration example of the drive unit in the third embodiment [Figure 12] Schematic diagram showing a configuration example of the drive unit in the fourth embodiment DETAILED DESCRIPTION OF THE INVENTION

[0010] Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic side view showing a configuration example of the hydraulic excavator 100 according to the present embodiment. FIG. 2 is a block diagram schematically showing the configuration of a hydraulic system and the like of the hydraulic excavator 100. The hydraulic excavator 100 is an example of the "working machine" of the present invention.

[0011] <1. Hydraulic Excavator 100> The hydraulic excavator 100 comprises a lower traveling body 200, a work implement 300, and an upper rotating body 400. In this embodiment, the upper rotating body 400 (particularly the part including the engine room 404 described later) may be collectively referred to as the "machine body".

[0012] In this disclosure, direction is defined as follows. First, the direction in which the lower vehicle 200 moves forward and backward is defined as the "forward-reverse direction." Of the "forward-reverse direction," the direction in which the lower vehicle 200 moves forward is defined as "forward," and the direction in which the lower vehicle 200 moves backward is defined as "rear." Therefore, when the upper rotating body 400 is not rotating relative to the lower vehicle 200 (rotation angle 0°), the forward-reverse direction of the lower vehicle 200 coincides with the direction from one side to the other of the driver's seat 4011, described later, in which the operator (driver, pilot) is seated in the upper rotating body 400.

[0013] Furthermore, when viewed from the rear towards the front, the direction from one side of the lower vehicle 200 to the other is referred to as the "left-right direction." Of the "left-right direction," the direction of the lower vehicle 200 toward the left is referred to as the "leftward direction," and the direction of the lower vehicle 200 toward the right is referred to as the "rightward direction."

[0014] Furthermore, the direction from one of the lower traveling body 200 and the upper rotating body 400 to the other is defined as the "up and down direction." Of the up and down directions, the direction from the lower traveling body 200 to the upper rotating body 400 is defined as "upward," and the direction from the upper rotating body 400 to the lower traveling body 200 is defined as "downward." Therefore, when the hydraulic excavator 100 is positioned on a horizontal plane with the vertical direction as the normal direction, the up and down direction of the hydraulic excavator 100 coincides with the vertical direction. Moreover, the upward direction coincides with the vertical upward direction, and the downward direction coincides with the vertical downward direction.

[0015] The front-to-back, left-to-right, and up-to-down directions are perpendicular to each other.

[0016] However, the above definition of direction is used merely for explanatory purposes and is not intended to limit actual positional relationships or directions.

[0017] <1-1. Lower running body 200> Figure 3 is a top view showing a schematic configuration example of the lower running body 200. As shown in Figures 1 and 3, the lower running body 200 comprises a track frame 201, an idler 202, a sprocket 203, an upper roller 204, a lower roller 205, a crawler 206, a holding member 207, and a drive unit 208.

[0018] The track frame 201 is a structural component of the lower running body 200. The track frame 201 comprises a center frame 2011, a pair of left and right side frames 2012, and a pair of left and right link frames 2013.

[0019] The center frame 2011 is a box-shaped structure that rotatably supports the upper rotating body 400. An opening 2014 is formed in the center of the top plate of the center frame 2011. A swivel bearing is positioned along the outer edge of the opening 2014 of the top plate, which rotatably connects the upper rotating body 400.

[0020] A pair of left and right side frames 2012 are connected via link frames 2013 to the lower sides of the center frame 2011 in the left-right direction. For example, the left side frame 2012 is positioned diagonally to the left and below (i.e., left and below) the left end of the center frame 2011 via the left link frame 2013. The right side frame 2012 is positioned diagonally to the left and below (i.e., left and below) the right end of the center frame 2011 via the right link frame 2013.

[0021] Each side frame 2012 extends in the front-to-back direction. As shown in Figure 2, each side frame 2012 is fitted with an idler 202, a sprocket 203, an upper roller 204, a lower roller 205, a crawler 206, a retaining member 207, and a drive unit 208.

[0022] Link frames 2013 connect the center frame 2011 to each of the side frames 2012. The right end of the left link frame 2013 connects to the left end of the center frame 2011. The left end of the left link frame 2013 is located below the right end and connects to the left side frame 2012. The left end of the right link frame 2013 connects to the right end of the center frame 2011. The right end of the right link frame 2013 is located below the left end and connects to the right side frame 2012.

[0023] The sprocket 203 is a gear-shaped drive wheel mounted on the side frame 2012. In this embodiment, the sprocket 203 is positioned at the rear end of the side frame 2012 and allows the crawler 206 to rotate seamlessly. The lower running body 200 is able to move using the sprockets 203 mounted on each of the side frames 2012.

[0024] The idler 202 is a free-moving wheel mounted on the side frame 2012 on the side opposite to the front-rear sprocket 203. In this embodiment, the idler 202 is rotatably connected to the front end of the side frame 2012. The upper roller 204 is rotatably positioned above the side frame 2012. The lower roller 205 is rotatably positioned below the side frame 2012. The idler 202, upper roller 204, and lower roller 205 guide the rotational movement of the crawler 206.

[0025] The crawler 206 is an annular track that spans across the idler 202, sprocket 203, upper roller 204, and lower roller 205. Multiple protrusions are arranged on the inner surface of the crawler 206, aligned in the direction of rotation. These protrusions engage with the teeth of the sprocket 203. As a result, the crawler 206 rotates in accordance with the rotation of the sprocket 203.

[0026] The drive unit 208 outputs driving force to the sprocket 203, causing it to rotate. The power source of the drive unit 208 (for example, the electric motor 11 described later) is supported at the rear end of the center frame 2011. The output terminal of the drive unit 208 is connected to the sprocket 203. The detailed configuration of the drive unit 208 will be described later.

[0027] The retaining member 207 holds the output terminal of the drive unit 208 relative to the side frame 2012. In this embodiment, it is positioned at the rear end of the side frame 2012.

[0028] <1-2. Work Machine 300> The work machine 300 comprises a boom 301, a boom cylinder 3011, an arm 302, an arm cylinder 3021, a bucket 303, and a bucket cylinder 3031. The hydraulic excavator 100 can perform excavation work such as soil by independently driving the boom 301, arm 302, and bucket 303. The base end of the boom 301 is supported at the front right side of the upper slewing body 400. The boom 301 is rotatable vertically relative to the upper slewing body 400 by a boom cylinder 3011 that is retractable. The base end of the arm 302 is connected to the tip of the boom 301. The arm 302 is rotatable vertically relative to the boom 301 by an arm cylinder 3021 that is retractable. The bucket 303 is supported at the tip of the arm 302. The bucket 303 is rotatable relative to the arm 302 by a bucket cylinder 3031 that is retractable and movable.

[0029] <1-3. Upper rotating body 400> The upper rotating body 400 is positioned above the lower running body 200 and is rotatable relative to the lower running body 200. The upper rotating body 400 includes a control unit 401, a body frame 402, a rotating motor 403, an engine room 404, and a bonnet 405.

[0030] The control unit 401 houses the driver's seat 4011. The operator sits in the driver's seat 4011. Various devices (operating levers, monitors, etc.) are arranged around the driver's seat 4011. By the operator sitting in the driver's seat 4011 and operating the operating levers, etc., the hydraulic actuator 4084 and hydraulic motor 4085, which will be described later, are driven. As a result, the hydraulic excavator 100 can perform tasks such as moving the lower traveling body 200, excavating with the work equipment 300, and rotating the upper rotating body 400.

[0031] The aircraft frame 402 is the base of the aircraft and is a plate-like structure that extends vertically and vertically. The control unit 401, the swing motor 403, and various equipment mounted in the engine room 404 are mounted on the aircraft frame 402.

[0032] The slewing motor 403 rotates the upper slewing body 400 via a slewing bearing. In this embodiment, the slewing motor 403 is a hydraulic motor, but it is not limited to this example and may be an electric motor. The engine room 404 is the internal space of the aircraft surrounded by the aircraft frame 402 and the bonnet 405, and is located below the control unit 401.

[0033] The upper rotating body 400 further includes a battery unit 406, a motor 407, a hydraulic pump 4081, a reservoir 4082, a control valve 4083, a hydraulic actuator 4084, and a hydraulic motor 4085 (see Figure 2). The battery unit 406, motor 407, hydraulic pump 4081, reservoir 4082, and control valve 4083 are housed in the engine room 404.

[0034] The battery unit 406 has a rechargeable secondary battery, such as a lithium-ion battery, and supplies power to components of the hydraulic excavator 100 that require power (for example, a motor 407). The motor 407 drives the hydraulic pump 4081.

[0035] The hydraulic pump 4081 supplies hydraulic fluid from the reservoir 4082 to the control valve 4083. The reservoir 4082 is a working fluid tank that stores the hydraulic fluid. The control valve 4083 has multiple directional control valves and controls the flow (flow direction and flow rate, etc.) of the working fluid pumped from the hydraulic pump 4081. For example, the control valve 4083 supplies the working fluid to the hydraulic actuator 4084 and the hydraulic motor 4085, etc. The hydraulic actuator 4084 includes, for example, a boom cylinder 3011, an arm cylinder 3021, and a bucket cylinder 3031. The hydraulic motor 4085 includes, for example, a slewing motor 403.

[0036] Furthermore, the hydraulic excavator 100 may be configured in combination with hydraulic equipment such as a hydraulic actuator 4084 and a hydraulic motor 4085, as well as an actuator driven by electric power. Examples of actuators driven by electric power include an electric travel motor, an electric cylinder, and an electric swing motor.

[0037] <1-4. Drive Unit 208> Next, with reference to Figures 3 to 5, an example of the configuration of the drive unit 208 in the first embodiment will be described. Figure 4 is a rear view showing an example of the configuration of the drive unit 208 in the first embodiment. Figure 5 is a rear view showing another example of the configuration of the drive unit 208 in the first embodiment. The structures of the left and right drive units 208 are symmetrical and otherwise identical. Therefore, in describing the configuration of the drive unit 208, the example of the configuration of the left drive unit 208L will be described, and the description of the configuration of the right drive unit 208 will be omitted. Also, Figures 4 and 5 are views of the left drive unit 208L as seen from the rear looking forward. In Figures 4 and 5, the left side corresponds to the outward direction in the left-right direction, and the right side corresponds to the inward direction in the left-right direction.

[0038] As shown in Figures 3 to 5, the drive unit 208 includes an output unit 1, a drive unit 2, and a transmission mechanism 3. The output unit 1 generates a driving force (rotational force) to rotate the sprocket 203 and outputs this driving force to the sprocket 203 via the transmission mechanism 3 and the drive unit 2. The output unit 1 is supported by the center frame 2011. The output unit 1 is positioned horizontally at the rear end of the center frame 2011 such that the output shaft 14 that outputs the driving force faces outward in the left-right direction (i.e., to the left). The drive unit 2 is positioned diagonally below and diagonally behind the output unit 1, and drives the sprocket 203. The transmission mechanism 3 transmits the driving force from the output unit 1 to the sprocket 203. For example, the transmission mechanism 3 connects the output unit 1 and the drive unit 2 and transmits the driving force (rotational force) transmitted from the output unit 1 to the drive unit 2. The drive unit 2 rotates the sprocket 203 using the driving force (rotational force) from the output unit 1, which is transmitted via the transmission mechanism 3.

[0039] Furthermore, in Figures 3 to 5, the output unit 1 is positioned away from the drive unit 2 in the left-right direction. However, the examples in Figures 3 to 5 do not exclude configurations in which the left-right position of a part of the output unit 1 is the same as the left-right position of a part of the drive unit 2.

[0040] Furthermore, the output unit 1 is positioned inward (forward) in the front-to-back direction from the rotation axis J1 of the sprocket 203 when viewed from above (see Figure 3). The rotation axis J1 extends in the left-to-right direction, passing through the rotation center of the sprocket 203. However, this example does not exclude configurations in which a part of the output unit 1 overlaps with the rotation axis J1 when viewed from above.

[0041] <1-4-1. Output Section 1> The output unit 1, for example in Figure 4, includes an electric motor 11, a brake device 12, an output shaft 14, an output gear 15, and an output cover 16. The electric motor 11, brake device 12, output shaft 14, and output gear 15 are arranged in the above order from the inside to the outside in the left-right direction. The output unit 1 outputs the driving force of the electric motor 11.

[0042] The electric motor 11 is supported by the center frame 2011 and is positioned horizontally such that its output shaft (not shown) faces outward in the left-right direction (i.e., to the left). The output shaft of the electric motor 11 extends along the motor rotation axis J2 and is rotatable around the motor rotation axis J2. The motor rotation axis J2 is parallel to the left-right direction, as shown in Figures 3 and 4.

[0043] The brake device 12 is, for example, a parking brake and is located on the left-right outward side of the electric motor 11. The brake device 12 suppresses or prevents the transmission of driving force from the electric motor 11 to the output shaft 14 in response to the operator's movements in the control unit 401. In other words, when the brake device 12 is activated, the transmission of driving force is suppressed or prevented. On the other hand, when the brake device 12 is deactivated, the transmission of driving force is neither suppressed nor prevented. Alternatively, the brake device 12 suppresses or prevents the driving (rotation) of the output shaft, output shaft 14, etc. of the electric motor 11 in response to the operator's movements in the control unit 401. The configuration of the brake device 12 is not particularly limited. For example, the brake device 12 may be an electromagnetic clutch type, a mechanical type, or a hydraulic type.

[0044] The output shaft portion 14 is connected to the output shaft of the electric motor 11 and extends along the motor rotation axis J2. At least a portion of the output shaft portion 14 protrudes outward in the left-right direction from the left-right outward end of the brake device 12.

[0045] The output gear 15 is mounted on the output shaft portion 14. More specifically, the output gear 15 is positioned on the left-right outward side of the output shaft portion 14 and extends radially with respect to the motor rotation axis J2. In Figure 4, the output gear 15 is a bevel gear and is positioned at the left-right outward end of the output shaft portion 14. The output gear 15 engages with the output portion 1 side end of the transmission mechanism 3.

[0046] In this embodiment, the output shaft portion 14 extends in a direction parallel to the rotation axis J1 of the sprocket 203. That is, the motor rotation axis J2 is parallel to the rotation axis J1 of the sprocket 203. In this way, the output unit 1 can output driving force outward in the left-right direction (i.e., towards the sprocket 203 in the left-right direction). This makes it possible to shorten the distance in the left-right direction between the output end of the output shaft portion 14 and the sprocket 203 side. Therefore, the output unit 1 can be moved away from the road surface while suppressing an increase in the length of the driving force transmission path (for example, the transmission shaft portion 33) from the output unit 1 side to the sprocket 203 side.

[0047] The output shaft 14 and the output gear 15 are rotatable together with the output shaft of the electric motor 11 around the motor rotation axis J2. The output shaft 14 outputs the driving force of the electric motor 11 to the transmission mechanism 3 via the output gear 15.

[0048] The output cover 16 is positioned at the left-right outward end of the brake device 23 and covers the output shaft portion 14 and the output gear 15, etc. An opening 161 is formed in the center of the left-right outward end of the output cover 16. The output gear 15 engages with the transmission mechanism 3 through the opening 161. Note that the example in Figure 4 does not exclude a configuration in which at least a part of the output gear 15 is positioned outside the output cover 16 through the opening 161, nor does it exclude a configuration in which the left-right outward end of the output shaft portion 14 is positioned outside the output cover 16 through the opening 161.

[0049] Furthermore, the edge of the output cover 16 along the outer edge of the opening 161 is connected to and covered by the inward end in the left-right direction of the transmission cover 34 of the transmission mechanism 3. The output cover 16 and the transmission cover 34 prevent dust (especially sand and dust generated when the lower traveling body moves back and forth or turns, splashed water, mud, etc.) from adhering to the output shaft 14 and output gear 15, or from entering their interiors.

[0050] <1-4-2. Drive Unit 2> The drive unit 2 includes an input shaft 21, a passive gear 22, a reduction gear 24, a drive shaft 25, a drive bearing 26, and an input cover 27. The input cover 27, passive gear 22, input shaft 21, reduction gear 24, and drive shaft 25 are arranged in this order from the inside to the outside in the left-right direction.

[0051] The input shaft portion 21 extends parallel to the rotation axis J1, and in Figure 4, it extends along the rotation axis J1. In Figure 4, the left and right outer ends of the input shaft portion 21 are connected to the input shaft of the reduction gear 24, which extends inward in the left and right directions along the rotation axis J1. Alternatively, the input shaft portion 21 may be the input shaft of the reduction gear 24.

[0052] The passive gear 22 is mounted on the input shaft portion 21. The passive gear 22 is positioned on the left-right inward side of the input shaft portion 21, and further inward in the left-right direction than the reduction gear 24. The passive gear 22 expands radially with respect to an axis (e.g., rotation axis J1) that extends left-right through the center of the input shaft portion 21. In Figure 4, the passive gear 22 is a bevel gear and is positioned at the left-right inward end of the input shaft portion 21. The passive gear 22 engages with the drive unit 2 side end of the transmission mechanism 3. The passive gear 22 is rotatable together with the input shaft of the input shaft portion 21 and the input shaft of the reduction gear 24 about an axis (e.g., rotation axis J1) that extends left-right through the center of the input shaft portion 21. As a result, the driving force output from the transmission mechanism 3 to the passive gear 22 is input to the reduction gear 24.

[0053] The reduction gear 24 increases the driving force transmitted from the transmission mechanism 3 by reducing it at a predetermined reduction ratio and outputs it to the sprocket 203. In Figure 4, the reduction gear 24 is positioned between the passive gear 22 and the drive shaft 25 (and sprocket 203), and increases the driving force input to the input shaft by reducing it at a predetermined reduction ratio and outputs it to the drive shaft 25. In this way, the drive unit 2 can efficiently output the driving force increased by the reduction gear 24 to the nearest sprocket 203, depending on the position of the reduction gear 24.

[0054] The drive shaft portion 25 extends along the rotation axis J1. The sprocket 203 extends radially outward from the outer circumferential surface of the drive shaft portion 25 with respect to the rotation axis J1. The left and right inner ends of the drive shaft portion 25 are connected to the output shaft of the reduction gear 24, which extends left and right outward along the rotation axis J1. Alternatively, the drive shaft portion 25 may be the output shaft of the reduction gear 24.

[0055] The drive shaft 25, together with the output shaft and sprocket 203 of the reduction gear 24, is rotatable around the rotation axis J1. As a result, the driving force output from the transmission mechanism 3 is output to the sprocket 203. In other words, the sprocket 203 rotates due to this driving force, causing the crawler 206 to rotate seamlessly.

[0056] The drive shaft portion 25 is rotatably held by the retaining member 207 via a drive bearing 26. For example, in this embodiment, the drive bearing 26 is a ball bearing. The inner ring of the drive bearing 26 is connected to the drive shaft portion 25. An opening is formed at the left-right outward end of the retaining member 207. A bearing retaining portion for holding the outer ring of the drive bearing 26 is positioned at the edge of the opening. In this way, the outer ring of the drive bearing 26 is fixed to the retaining member 207.

[0057] The input cover 27 is a plate-shaped member that extends in a direction intersecting the left-right direction, and is positioned outward in the left-right direction (to the right in Figure 4) from the passive gear 22. An opening 271 is formed in the input cover 27. The passive gear 22 engages with the transmission mechanism 3 through the opening 271. Note that the example in Figure 4 does not exclude a configuration in which at least a part of the passive gear 22 is positioned outside the input cover 27 through the opening 271, nor does it exclude a configuration in which the left-right outward end of the input shaft portion 21 is positioned outside the input cover 27 through the opening 271.

[0058] Furthermore, the outer edge of the input cover 27 is connected to the inner surface of the retaining member 207 and the rear end surface of the side frame 2012. The edge of the input cover 27 along the outer edge of the opening 271 is connected to and covered by the left-right outward end of the transmission cover 34 of the transmission mechanism 3. As a result, the input cover 27, together with the retaining member 207 and the transmission cover 34, covers the left-right inward portion of the drive unit 2 excluding the input cover 27. For example, the input shaft 21, passive gear 22, reduction gear 24, and drive bearing 26 are covered. This prevents dust (especially sand and dust generated during the movement and turning of the lower traveling body, splashed water, mud, etc.) from adhering to the above-mentioned parts or entering their interiors.

[0059] <1-4-3. Transmission Mechanism 3> The transmission mechanism 3 includes a transmission shaft 33, a first transmission gear 31, a second transmission gear 32, and a transmission cover 34. The transmission shaft 33 extends along the rotation axis J3. The rotation axis J3 extends diagonally downward and diagonally backward as it moves outward in the left-right direction. The first transmission gear 31 and the second transmission gear 32 are bevel gears, and they expand radially with respect to the rotation axis J3.

[0060] The first transmission gear 31 is mounted on the output section 1 side of the transmission shaft 33. The second transmission gear 32 is mounted on the drive section 2 side of the transmission shaft 33. In this case, for example, the first transmission gear 31 is engaged with the output section 1, and the second transmission gear 32 is engaged with the sprocket 203 side. As a result, the transmission mechanism 3 can transmit the driving force of the electric motor 11 to the sprocket 203 side with a simple configuration.

[0061] The first transmission gear 31 meshes with the output gear 15 of the output unit 1. The second transmission gear 32 meshes with the passive gear 22 of the drive unit 2. The transmission shaft 33, the first transmission gear 31, and the second transmission gear 32 are rotatable around the rotation axis J3. In this way, the meshing structure of the first transmission gear 31 and the output gear 15, and the meshing structure of the second transmission gear 32 and the passive gear 22, enable the driving force of the electric motor 11 to be transmitted to the sprocket 203.

[0062] The transmission cover 34 is a cylindrical member that houses the first transmission gear 31, the second transmission gear 32, and the transmission shaft portion 33, and extends along the transmission shaft portion 33. As described above, the end of the transmission cover 34 on the output portion 1 side is connected to the edge of the output cover 16 along the outer edge of the opening 161. The end of the transmission cover 34 on the drive portion 2 side is connected to the edge of the input cover 27 along the outer edge of the opening 271. This prevents dust (especially sand and dust generated when the lower traveling body 200 moves back and forth and turns, as well as splashed water and mud) from adhering to the components inside the transmission cover 34 (for example, the transmission shaft portion 33, the first transmission gear 31, and the second transmission gear 32) or entering the interior of those components.

[0063] The transmission shaft 33 extends from the output shaft 14 side and transmits the driving force output from the output 1 to the sprocket 203 side. The transmission shaft 33 extends downward from the output shaft 14 side toward the sprocket 203 side, in other words, it extends outward in the left-right direction and diagonally downward.

[0064] In this configuration, the output unit 1 is positioned further inward and upward from the sprocket 203 in the left-right direction. Consequently, the hydraulic excavator 100 can position the output unit 1, including the electric motor 11, further away from the road surface on which the lower traveling body 200 travels. Therefore, even when traveling on a rough road surface, the hydraulic excavator 100 can suppress or prevent the output unit 1 (especially the electric motor 11) from coming into contact with soil, rocks, or other objects exposed on the road surface.

[0065] Furthermore, the hydraulic excavator 100 can position the output unit 1, including the electric motor 11, away from the sprocket 203 mounted on the side frame 2012, in the left-right direction. Therefore, the hydraulic excavator 100 can prevent interference between the output unit 1 (especially the electric motor 11) and components mounted on the side frame 2012 (such as the sprocket 203 and crawler 206), while improving the flexibility of the arrangement design for both.

[0066] Furthermore, the hydraulic excavator 100 can suppress or prevent soil, rocks, mud, etc., that are kicked up from the road surface by the sprocket 203 and crawler 206, etc., from hitting the output unit 1 while it is in motion.

[0067] Preferably, the transmission shaft portion 33 extends further outward in the longitudinal direction (i.e., rearward) as it moves from the output shaft portion 14 side toward the sprocket 203 side (see Figure 3). In this way, the output unit 1 is positioned inward in the longitudinal direction relative to the sprocket 203. Therefore, the output unit 1 supported by the center frame 2011 can be compactly arranged. Also, the output unit 1 can be positioned further inward in the longitudinal direction relative to the sprocket 203. Therefore, the hydraulic excavator 100 can further suppress or prevent soil, rocks, mud, etc., kicked up from the road surface by the sprocket 203 and crawler 206, etc., from hitting the output unit 1 during operation. However, this example does not exclude a configuration in which the transmission shaft portion 33 does not extend outward in the longitudinal direction as it moves from the output shaft portion 14 side toward the sprocket 203 side.

[0068] <1-4-4. Other configuration examples of drive unit 208> Next, with reference to Figure 5, another example of the drive unit 208 configuration will be described. The drive unit 208 includes an output unit 1, a drive unit 2, and a transmission mechanism 3. In Figure 5, as in Figure 4, the output unit 1 is positioned horizontally at the rear end of the center frame 2011 such that the output shaft 14 that outputs driving force faces outward in the left-right direction (i.e., to the left).

[0069] The output unit 1 includes an electric motor 11, a brake device 12, a reduction gear 13, an output shaft 14, an output gear 15, and an output cover 16. The electric motor 11, brake device 12, reduction gear 13, output shaft 14, and output gear 15 are arranged in the above order from the inside to the outside in the left-right direction.

[0070] The electric motor 11 outputs a driving force (rotational force) to the input shaft of the reduction gear 13. The braking device 12 is, for example, a parking brake and is located between the electric motor 11 and the reduction gear 13.

[0071] The braking device 12 suppresses or prevents the transmission of driving force from the electric motor 11 to the input shaft of the reduction gear 13 in response to the operator's movements in the control unit 401. Alternatively, the braking device 12 suppresses or prevents the drive (rotation) of the output shaft of the electric motor 11, the input shaft of the reduction gear 13, etc., in response to the operator's movements in the control unit 401.

[0072] The reduction gear 13 is positioned on the left-right outward side of the brake device 12. The reduction gear 13 increases the driving force input to the input shaft by reducing it at a predetermined reduction ratio and outputs it to the output gear 15 via the output shaft 14. In other words, the output unit 1 increases the driving force output from the electric motor 11 by reducing it at a predetermined reduction ratio and outputs it to the transmission mechanism 3. As a result, the output unit 1 can efficiently output and increase the driving force of the electric motor 11 to the nearest reduction gear 13 due to the arrangement of the reduction gear 13. Furthermore, the output unit 1 can output a larger driving force to the transmission mechanism 3.

[0073] The output shaft portion 14 is connected to the output shaft of the reduction gear 13 and extends along the motor rotation axis J2. At least a portion of the output shaft portion 14 protrudes outward in the left-right direction from the left-right outward end of the reduction gear 13. However, the example is not limited to this, and the output shaft portion 14 may be the same member as the output shaft of the reduction gear 13.

[0074] The output cover 16 is positioned at the left-right outer end of the reduction gear 13 and covers the output shaft 14 and the output gear 15, etc.

[0075] Next, the drive unit 2 includes an input shaft 21, a passive gear 22, a drive bearing 26, and an input cover 27.

[0076] The input shaft portion 21 extends along the rotation axis J1 and is connected to the sprocket 203. The rotation axis J1 extends in the left-right direction, passing through the rotation center of the sprocket 203.

[0077] The passive gear 22 is positioned on the left-right inward side of the input shaft portion 21, further inward in the left-right direction than the sprocket 203 and the drive bearing 26. In Figure 5, the passive gear 22 is a bevel gear and is positioned at the left-right inward end of the input shaft portion 21.

[0078] The input shaft 21, together with the passive gear 22 and the sprocket 203, is rotatable around the rotation axis J1. As a result, the driving force output from the transmission mechanism 3 to the passive gear 22 is transmitted to the sprocket 203. In other words, the sprocket 203 rotates due to this driving force, causing the crawler 206 to rotate seamlessly.

[0079] Furthermore, the input shaft portion 21 is rotatably held by the retaining member 207 via a drive bearing 26. For example, in this embodiment, the drive bearing 26 is a ball bearing. The inner ring of the drive bearing 26 is connected to the input shaft portion 21. The outer ring of the drive bearing 26 is fixed to the retaining member 207.

[0080] Note that the configurations of the output unit 1 and the drive unit 2 are not limited to the examples shown in Figures 4 and 5. For example, the output unit 1 in the first embodiment may have at least an electric motor 11, an output shaft 14, an output gear 15, and an output cover 16. The drive unit 2 in the first embodiment may have at least an input shaft 21, a passive gear 22, a drive bearing 26, and an input cover 27. Furthermore, in these cases, the brake devices 12, 23 and the reduction gears 13, 24 may each be located in at least one of the output unit 1 and the drive unit 2. However, this example does not exclude configurations in which the brake devices 12, 23 and the reduction gears 13, 24 are not located in either the output unit 1 or the drive unit 2.

[0081] <1-4-5. First to Fifth Configuration Examples of Output Unit 1> Figure 6A is a schematic diagram showing a first configuration example of the output unit 1 in the first embodiment. Figure 6B is a schematic diagram showing a second configuration example of the output unit 1 in the first embodiment. Figure 6C is a schematic diagram showing a third configuration example of the output unit 1 in the first embodiment. Figure 6D is a schematic diagram showing a fourth configuration example of the output unit 1 in the first embodiment. Figure 6E is a schematic diagram showing a fifth configuration example of the output unit 1 in the first embodiment. Figures 6A to 6E show the output unit 1 of the left drive unit 208L viewed from the rear, facing forward. In Figures 6A to 6E, the left side corresponds to the outward direction in the left-right direction, and the right side corresponds to the inward direction in the left-right direction.

[0082] (First configuration example of output unit 1) The output unit 1 of the first configuration example shown in Figure 6A has the same configuration as the output unit 1 in Figure 5, and includes an electric motor 11, a brake device 12, a reduction gear 13, an output shaft 14, an output gear 15, and an output cover 16. The electric motor 11, brake device 12, reduction gear 13, output shaft 14, and output gear 15 are arranged in the above order from the inside to the outside in the left-right direction.

[0083] The brake device 12 may be positioned on the left-right inward side of the reduction gear 13.

[0084] (Second configuration example of output unit 1) The output unit 1 of the second configuration example shown in Figure 6B includes an electric motor 11, a brake device 12, a reduction gear 13, an output shaft 14, an output gear 15, and an output cover 16. The electric motor 11, reduction gear 13, brake device 12, output shaft 14, and output gear 15 are arranged in this order from the inside to the outside in the left-right direction.

[0085] The electric motor 11 outputs a driving force (rotational force) to the input shaft of the reduction gear 13. The reduction gear 13 is located on the left-right outward side of the electric motor 11 and increases the driving force input to the input shaft by reducing it at a predetermined reduction ratio, and outputs it to the output gear 15 via the output shaft 14.

[0086] The brake device 12 suppresses or prevents the transmission of driving force from the output shaft of the reduction gear 13 to the output shaft portion 14 in response to the operator's movements in the control unit 401. Alternatively, the brake device 12 suppresses or prevents the driving (rotation) of the output shaft, output shaft portion 14, etc. of the reduction gear 13 in response to the operator's movements in the control unit 401.

[0087] The output shaft portion 14 is connected to the output shaft of the reduction gear 13 and extends along the motor rotation axis J2. At least a portion of the output shaft portion 14 protrudes outward in the left-right direction from the left-right outward end of the brake device 12. In the output portion 1 of the second configuration example, the output shaft portion 14 may be made of a different material from the output shaft of the reduction gear 13, or it may be made of the same material as the output shaft of the reduction gear 13.

[0088] The output cover 16 is positioned at the left-right outer end of the brake device 12 and covers the output shaft 14 and the output gear 15, etc.

[0089] (Third configuration example of output unit 1) The output unit 1 of the third configuration example shown in Figure 6C has the same configuration as the output unit 1 in Figure 4, and includes an electric motor 11, a brake device 12, an output shaft 14, an output gear 15, and an output cover 16. The electric motor 11, brake device 12, output shaft 14, and output gear 15 are arranged in the above order from the inside to the outside in the left-right direction.

[0090] (Fourth example configuration of output unit 1) The output unit 1 of the fourth configuration example shown in Figure 6D includes an electric motor 11, a reduction gear 13, an output shaft 14, an output gear 15, and an output cover 16. The electric motor 11, reduction gear 13, output shaft 14, and output gear 15 are arranged in the above-described order from the inside to the outside in the left-right direction.

[0091] The electric motor 11 outputs a driving force (rotational force) to the input shaft of the reduction gear 13. The reduction gear 13 is located on the left-right outward side of the electric motor 11 and increases the driving force input to the input shaft by reducing it at a predetermined reduction ratio, and outputs it to the output gear 15 via the output shaft 14.

[0092] The output shaft portion 14 is connected to the output shaft of the reduction gear 13 and extends along the motor rotation axis J2. At least a portion of the output shaft portion 14 protrudes outward in the left-right direction from the left-right outward end of the reduction gear 13. However, the example is not limited to this, and the output shaft portion 14 may be the same member as the output shaft of the reduction gear 13.

[0093] The output cover 16 is positioned at the left-right outer end of the reduction gear 13 and covers the output shaft 14 and the output gear 15, etc.

[0094] (Fifth configuration example of output unit 1) The output unit 1 of the fifth configuration example shown in Figure 6E includes an electric motor 11, an output shaft 14, an output gear 15, and an output cover 16. The electric motor 11, the output shaft 14, and the output gear 15 are arranged in the above-described order from the inside to the outside in the left-right direction.

[0095] The electric motor 11 outputs driving force (rotational force) to the output gear 15 via the output shaft portion 14. The output shaft portion 14 is connected to the output shaft of the electric motor 11 and extends along the motor rotation axis J2. Note that this is not an example, and the output shaft portion 14 may be the same component as the output shaft of the electric motor 11. The output cover 16 is positioned at the left-right outward end of the electric motor 11 and covers the output shaft portion 14 and the output gear 15, etc.

[0096] <1-4-6. First to Fifth Configuration Examples of the Drive Unit 2> Figure 7A is a schematic diagram showing a first configuration example of the drive unit 2. Figure 7B is a schematic diagram showing a second configuration example of the drive unit 2. Figure 7C is a schematic diagram showing a third configuration example of the drive unit 2. Figure 7D is a schematic diagram showing a fourth configuration example of the drive unit 2. Figure 7E is a schematic diagram showing a fifth configuration example of the drive unit 2. Figures 7A to 7E show the drive unit 2 of the left drive unit 208L as seen from the rear looking forward. In Figures 7A to 7E, the left side corresponds to the outward direction in the left-right direction, and the right side corresponds to the inward direction in the left-right direction.

[0097] (First configuration example of drive unit 2) The drive unit 2 of the first configuration example shown in Figure 7A includes an input shaft 21, a passive gear 22, a brake device 23, a reduction gear 24, a drive shaft 25, a drive bearing 26, and an input cover 27. The input cover 27, passive gear 22, input shaft 21, brake device 23, reduction gear 24, and drive shaft 25 are arranged in this order from the inside to the outside in the left-right direction.

[0098] The input shaft portion 21 extends parallel to the rotation axis J1, for example, along the rotation axis J1. The left and right outer ends of the input shaft portion 21 are connected to the input shaft of the reduction gear 24, which extends left and right inward along the rotation axis J1. Alternatively, the input shaft portion 21 may be the input shaft of the reduction gear 24.

[0099] The passive gear 22 is positioned on the left-right inward side of the input shaft portion 21 and engages with the end of the transmission mechanism 3 on the drive portion 2 side. The passive gear 22 is rotatable together with the input shaft portion 21 and the input shaft of the reduction gear 24 about an axis (for example, a rotation axis J1) that extends left-right through the center of the input shaft portion 21.

[0100] The brake device 23 is, for example, a parking brake and is positioned between the passive gear 22 and the reduction gear 24. The brake device 23 suppresses or prevents the transmission of driving force from the transmission mechanism 3 to the sprocket 203 in response to the operator's movements in the control unit 401. Alternatively, the brake device 23 suppresses or prevents the drive (rotation) of the input shaft 21, the output shaft of the reduction gear 24, etc., in response to the operator's movements in the control unit 401. The configuration of the brake device 23 is not particularly limited. For example, the brake device 23 may be an electromagnetic clutch type, a mechanical type, or a hydraulic type.

[0101] The reduction gear 24 is positioned between the brake device 23 and the drive shaft section 25 (and sprocket 203), and increases the driving force input to the input shaft by reducing it at a predetermined reduction ratio before outputting it to the drive shaft section 25.

[0102] The drive shaft portion 25 extends along the rotation axis J1. The left-right inner end of the drive shaft portion 25 is connected to the output shaft of the reduction gear 24, which extends left-right outward along the rotation axis J1. Alternatively, the drive shaft portion 25 may be the same component as the output shaft of the reduction gear 24. The drive shaft portion 25 is rotatable around the rotation axis J1 together with the output shaft and sprocket 203 of the reduction gear 24.

[0103] The drive bearing 26 is positioned between the reduction gear 24 and the sprocket 203. The drive shaft portion 25 is rotatably held by the retaining member 207 via the drive bearing 26. For example, in this embodiment, the drive bearing 26 is a ball bearing. The inner ring of the drive bearing 26 is connected to the drive shaft portion 25.

[0104] The brake device 23 may be positioned between the reduction gear 24 and the drive bearing 26.

[0105] (Second example of drive unit 2 configuration) The drive unit 2 in the second configuration example shown in Figure 7B includes an input shaft 21, a passive gear 22, a brake device 23, a reduction gear 24, a drive shaft 25, a drive bearing 26, and an input cover 27. The input cover 27, passive gear 22, input shaft 21, reduction gear 24, brake device 23, and drive shaft 25 are arranged in this order from the inside to the outside in the left-right direction.

[0106] The reduction gear 24 increases the driving force input to the input shaft via the input shaft section 21 by reducing it at a predetermined reduction ratio and outputs it to the drive shaft section 25.

[0107] The brake device 23 is, for example, a parking brake and is positioned between the reduction gear 24 and the drive shaft 25 (and sprocket 203). The brake device 23 suppresses or prevents the transmission of driving force from the reduction gear 24 to the drive shaft 25 (and sprocket 203) in response to the operator's movements in the control unit 401. Alternatively, the brake device 23 suppresses or prevents the drive (rotation) of the output shaft of the reduction gear 24, the drive shaft 25, etc., in response to the operator's movements in the control unit 401.

[0108] The drive shaft portion 25 extends along the rotation axis J1. The left-right inner end of the drive shaft portion 25 is connected to the output shaft of the reduction gear 24, which extends left-right outward along the rotation axis J1. Alternatively, the drive shaft portion 25 may be the same component as the output shaft of the reduction gear 24. The drive shaft portion 25 is rotatable around the rotation axis J1 together with the output shaft and sprocket 203 of the reduction gear 24.

[0109] The drive bearing 26 is positioned between the reduction gear 24 and the sprocket 203. The drive shaft portion 25 is rotatably held by the retaining member 207 via the drive bearing 26. For example, in this embodiment, the drive bearing 26 is a ball bearing. The inner ring of the drive bearing 26 is connected to the drive shaft portion 25.

[0110] (Third example configuration of the drive unit 2) The drive unit 2 in the third configuration example shown in Figure 7C has the same configuration as the drive unit 2 in Figure 4, and includes an input shaft 21, a passive gear 22, a reduction gear 24, a drive shaft 25, a drive bearing 26, and an input cover 27. The input cover 27, passive gear 22, input shaft 21, reduction gear 24, and drive shaft 25 are arranged in this order from the inside to the outside in the left-right direction.

[0111] (Fourth example configuration of the drive unit 2) The drive unit 2 of the fourth configuration example shown in Figure 7D includes an input shaft 21, a passive gear 22, a brake device 23, a drive bearing 26, and an input cover 27. The passive gear 22, input shaft 21, reduction gear 24, and drive shaft 25 are arranged in this order from the inside to the outside in the left-right direction.

[0112] The input shaft portion 21 extends along the rotation axis J1 and is connected to the sprocket 203. The rotation axis J1 extends in the left-right direction, passing through the rotation center of the sprocket 203. The input shaft portion 21 is rotatable around the rotation axis J1 together with the passive gear 22 and the sprocket 203. The input shaft portion 21 is also rotatably held by a retaining member 207 via a drive bearing 26. For example, the drive bearing 26 is a ball bearing in this embodiment. The inner ring of the drive bearing 26 is connected to the input shaft portion 21.

[0113] The brake device 23 is, for example, a parking brake and is positioned between the passive gear 22 and the sprocket 203. The brake device 23 suppresses or prevents the transmission of driving force from the input shaft 21 to the sprocket 203 in response to the operator's movements in the control unit 401. Alternatively, the brake device 23 suppresses or prevents the driving (rotation) of the input shaft 21, etc., in response to the operator's movements in the control unit 401.

[0114] (Fifth configuration example of the drive unit 2) The drive unit 2 of the fifth configuration example shown in Figure 7E has the same configuration as the drive unit 2 in Figure 5, and includes an input shaft 21, a passive gear 22, a drive bearing 26, and an input cover 27. The input cover 27, passive gear 22, input shaft 21, and sprocket 203 are arranged in this order from the inside to the outside in the left-right direction.

[0115] <1-4-7. Arrangement of brake devices 12 and 23> Preferably, the brake devices 12 and 23 are positioned between the electric motor 11 and the reduction gears 13 and 24 in the power transmission path. In this case, the brake devices 12 and 23 suppress or prevent the transmission of power from the electric motor 11 to the reduction gears 13 and 24.

[0116] For example, in Figure 4, in the drive unit 208, the brake device 12 is positioned between the electric motor 11 and the reduction gear 24 in the power transmission path.

[0117] Furthermore, in Figures 5 and 6A, in the output unit 1, the brake device 12 is positioned between the electric motor 11 and the reduction gear 13 in the driving force transmission path. In other words, preferably in the output unit 1 having a reduction gear 13, the brake device 12 is positioned between the electric motor 11 and the reduction gear 13 in the driving force transmission path (in other words, on the input end side of the reduction gear 13).

[0118] Furthermore, in Figure 7A, the brake device 23 is positioned between the passive gear 22 and the reduction gear 24 in the drive unit 2. In other words, preferably, in the drive unit 2 having a reduction gear 24, the brake device 23 is positioned between the electric motor 11 and the reduction gear 24 in the power transmission path (in other words, on the input end side of the reduction gear 24).

[0119] This allows the brake devices 12 and 23 to be positioned before the reduction gears 13 and 24 (on the input end side). The driving force output to the reduction gears 13 and 24 is less than the driving force output from the reduction gears 13 and 24. Therefore, the brake devices 12 and 23 can suppress or prevent the transmission of driving force from the electric motor 11 to the reduction gears 13 and 24 with a smaller load compared to a configuration where the brake devices 12 and 23 are positioned after the reduction gears 13 and 24 (on the output end side).

[0120] However, the above examples do not exclude configurations in which the brake devices 12 and 23 are not located between the electric motor 11 and the reduction gears 13 and 24 in the power transmission path. For example, in the drive unit 208, the brake devices 12 and 23 may be located between the reduction gears 13 and 24 and the sprocket 203 in the power transmission path. One example is a configuration in which the drive unit 208 has an output unit 1 as shown in Figure 6D and a drive unit 2 as shown in Figure 7D. Also, in the output unit 1 as shown in Figure 6A, the brake device 12 may be located between the reduction gear 13 and the output gear 15 in the power transmission path (in other words, on the output end side of the reduction gear 13). Also, in the drive unit 2 as shown in Figure 7B, the brake device 12 may be located between the sprocket 203 and the reduction gear 24 in the power transmission path (in other words, on the output end side of the reduction gear 24).

[0121] Preferably, as shown in Figures 7A, 7B, and 7D, the drive unit 2 has a brake device 23. The brake device 23 is positioned between the transmission mechanism 3 (or passive gear 22) and the sprocket 203 in the power transmission path to suppress or prevent the transmission of power to the sprocket 203. In this way, by positioning the brake device 23 in the hydraulic excavator 100 and the drive unit 2, the transmission of power to the sprocket 203 can be reliably suppressed or prevented. For example, even if the electric motor 11 becomes inoperable, the brake device 23 can reliably suppress or prevent the driving (rotation) of the sprocket 203. However, this example does not exclude configurations in which the drive unit 2 does not have a brake device 23, as shown in Figures 7C and 7E.

[0122] <2. Second Embodiment> Next, a second embodiment will be described. In the second embodiment, the output unit 1 is positioned diagonally horizontally such that the output shaft 14 faces outward and downward in the left-right direction. The following describes a configuration that differs from the first embodiment. The same reference numerals are used for components that are the same as in the first embodiment. Also, descriptions of components that are the same as in the first embodiment may be omitted.

[0123] Figure 8 is a rear view showing an example configuration of the drive unit 208 in the second embodiment. Figure 9 is a rear view showing another example configuration of the drive unit 208 in the second embodiment. The structures of the left and right drive units 208 are symmetrical and otherwise identical. Therefore, in the description of the configuration of the drive unit 208, the configuration example of the left drive unit 208L will be described, and the description of the configuration of the right drive unit 208 will be omitted. Also, Figures 8 and 9 are views of the left drive unit 208L as seen from the rear looking forward. In Figures 8 and 9, the left side corresponds to the outward direction in the left-right direction, and the right side corresponds to the inward direction in the left-right direction.

[0124] In Figure 8, the output section 1 of the drive unit 208 includes an electric motor 11, a brake device 12, an output shaft 14, and an output cover 16. The electric motor 11, brake device 12, and output shaft 14 are arranged in this order from the inside to the outside in the left-right direction.

[0125] Furthermore, in Figure 9, the output section 1 of the drive unit 208 includes an electric motor 11, a brake device 12, a reduction gear 13, an output shaft section 14, and an output cover 16. The electric motor 11, brake device 12, reduction gear 13, and output shaft section 14 are arranged in this order from the inside to the outside in the left-right direction.

[0126] In the second embodiment, the electric motor 11 is positioned diagonally horizontally such that the output shaft (not shown) is directed outward and downward in the left-right direction. The output shaft extends along the motor rotation axis J4 and is rotatable around the motor rotation axis J4. As shown in Figures 8 and 9, the motor rotation axis J4 extends downward as it is directed outward in the left-right direction. Preferably, the motor rotation axis J4 extends further outward in the left-right direction as it is directed outward in the left-right direction. However, this example does not exclude configurations in which the motor rotation axis J4 does not extend outward in the left-right direction as it is directed outward in the left-right direction.

[0127] The output shaft portion 14 is connected to the output shaft of the electric motor 11 and extends along the motor rotation axis J2. At least a portion of the output shaft portion 14 protrudes outward in the left-right direction from the left-right outward end of the brake device 12.

[0128] The configuration of the drive unit 2 in Figure 8 is the same as in Figure 4. Similarly, the configuration of the drive unit 2 in Figure 9 is the same as in Figure 5. Therefore, a description of the configuration of the drive unit 2 in the second embodiment is omitted.

[0129] The transmission mechanism 3 includes a transmission shaft 33, a transmission cover 34, and a transmission gear 35. The transmission shaft 33 is connected to the output shaft 14 and extends along the motor rotation axis J4. In other words, the output shaft 14 and the transmission shaft 33 extend along the same axis J4. This way, for example, even if the end of the output shaft 14 on the transmission mechanism 3 side is connected to the end of the transmission shaft 33 on the output shaft 14 side, both the output shaft 14 and the transmission shaft 33 can be rotated around the same axis J4. Therefore, the transmission shaft 33 can be connected to the output shaft 14 in a simple configuration so that it can rotate together. Note that this is not an example, and the transmission shaft 33 may be made of the same material as the output shaft 14.

[0130] The transmission gear 35 is a bevel gear and expands radially with respect to the motor rotation shaft J4. The transmission gear 35 is located on the drive unit 2 side of the transmission shaft portion 33 and meshes with the passive gear 22 of the drive unit 2. The transmission gear 35, together with the output shaft portion 14 and the transmission shaft portion 33, is rotatable around the motor rotation shaft J4.

[0131] The transmission cover 34 is a cylindrical member that houses the transmission shaft portion 33 and the transmission gear 35, and extends along the transmission shaft portion 33.

[0132] Note that the configuration of the output unit 1 and the drive unit 2 in the second embodiment is not limited to the examples shown in Figures 8 and 9. For example, the output unit 1 in the second embodiment may have at least an electric motor 11, an output shaft 14, and an output cover 16. The drive unit 2 in the second embodiment may have at least an input shaft 21, a passive gear 22, a drive bearing 26, and an input cover 27. Furthermore, in these cases, the brake devices 12, 23 and the reduction gears 13, 24 may each be located in at least one of the output unit 1 and the drive unit 2. However, this example does not exclude configurations in which the brake devices 12, 23 and the reduction gears 13, 24 are not located in either the output unit 1 or the drive unit 2.

[0133] In the second embodiment, each component of the output unit 1 can be arranged in the same manner as in Figures 6A to 6E of the first embodiment, except for the direction in which the output gear 15 and the motor rotation shaft J4 extend.

[0134] Figure 10A is a schematic diagram showing a first configuration example of the output unit 1 in the second embodiment. Figure 10B is a schematic diagram showing a second configuration example of the output unit 1 in the second embodiment. Figure 10C is a schematic diagram showing a third configuration example of the output unit 1 in the second embodiment. Figure 10D is a schematic diagram showing a fourth configuration example of the output unit 1 in the second embodiment. Figure 10E is a schematic diagram showing a fifth configuration example of the output unit 1 in the second embodiment. Figures 10A to 10E show the output unit 1 of the left drive unit 208L viewed from the rear, facing forward. In Figures 10A to 10E, the left side corresponds to the outward direction in the left-right direction, and the right side corresponds to the inward direction in the left-right direction.

[0135] For example, in the output unit 1 shown in Figures 10A to 10E, the output gear 15 is not located on the transmission mechanism 3 side of the output shaft 14. Also, the end of the output shaft 14 on the transmission mechanism 3 side is connected to the end of the transmission shaft 33 on the output unit side. Apart from these, each component of the output unit 1 in Figures 10A to 10E is arranged along the motor rotation axis J4 in the same manner as in Figures 6A to 6E.

[0136] Furthermore, each component of the drive unit 2 in the second embodiment can be arranged in the same manner as in Figures 7A to 7E of the first embodiment.

[0137] <3. Third Embodiment> Next, a third embodiment will be described. In the third embodiment, the output unit 1 is arranged horizontally such that the output shaft 14 faces outward in the front-rear direction. The following describes a configuration that differs from the first and second embodiments. The same reference numerals are used for components that are the same as in the first and second embodiments. Also, descriptions of configurations that are the same as in the first and second embodiments may be omitted.

[0138] Figure 11 is a rear view showing an example of the configuration of the drive unit 208 in the third embodiment. The structures of the left and right drive units 208 are symmetrical and otherwise identical. Therefore, in the explanation of the configuration of the drive unit 208, the configuration example of the left drive unit 208L will be explained, and the explanation of the configuration of the right drive unit 208 will be omitted. Also, Figure 11 is a view of the left drive unit 208L as seen from the rear looking forward. In Figure 11, the left side corresponds to the outward direction in the left-right direction, and the right side corresponds to the inward direction in the left-right direction.

[0139] In Figure 11, the configuration of the output unit 1, drive unit 2, and transmission mechanism 3 is the same as in Figure 4, except for the arrangement of the output unit 1. In the output unit 1 of Figure 11, the output shaft, output shaft portion 14, etc. of the electric motor 11 extend along the motor rotation axis J5. The motor rotation axis J5 extends in a direction perpendicular to the vertical direction and the direction in which the rotation axis J1 of the sprocket 203 extends, that is, parallel to the front-rear direction. For example, the output shaft of the electric motor 11 protrudes outward (rearward) in the front-rear direction from the main end portion of the electric motor 11. The output shaft portion 14 is positioned outward (rearward) from the electric motor 11 in the front-rear direction and extends in the front-rear direction.

[0140] According to the third embodiment, the output unit 1 can be placed horizontally with the output shaft portion 14 extending in the front-rear direction. Therefore, even if the number of components arranged in the front-rear direction increases, the size of the output unit 1 in the left-right and up-down directions does not increase easily. Consequently, the output unit 1 can be compactly positioned away from the road surface.

[0141] <4. Fourth Embodiment> Next, a fourth embodiment will be described. In the fourth embodiment, each end of the transmission shaft portion 33 of the transmission mechanism 3 is connected to the output shaft portion 14 of the output portion 1 and the input shaft portion 21 of the drive portion 2 by universal joints 41, 42 (for example, universal joints), instead of a bevel gear meshing structure. The following describes a configuration that differs from the first to third embodiments. The same reference numerals are used for components that are the same as those in the first to third embodiments. Also, the description of configurations that are the same as those in the first to third embodiments may be omitted.

[0142] Figure 12 is a schematic diagram showing an example of the configuration of the drive unit 208 in the fourth embodiment. The structures of the left and right drive units 208 are symmetrical and otherwise identical. Therefore, in the explanation of the configuration of the drive unit 208, the configuration example of the left drive unit 208L will be explained, and the explanation of the configuration of the right drive unit 208 will be omitted. Also, Figure 12 is a view of the left drive unit 208L from the rear looking forward. In Figure 12, the left side corresponds to the outward direction in the left-right direction, and the right side corresponds to the inward direction in the left-right direction.

[0143] As shown in Figure 12, the end of the transmission shaft 33 on the output section 1 side is connected to the end of the output shaft 14 on the transmission mechanism 3 side by a universal joint 41 so as to be able to rotate three-dimensionally. In other words, the connection angle between the two can be freely changed. For example, at the connection point between the two, the transmission shaft 33 is rotatable in the pitch direction and the yaw direction relative to the output shaft 14.

[0144] Similarly, the end of the transmission shaft 33 on the drive unit 2 side is connected to the end of the input shaft 21 on the transmission mechanism 3 side by a universal joint 42, allowing for three-dimensional rotation. In other words, the connection angle between the two can be freely changed. For example, at the connection point between the two, the transmission shaft 33 is rotatable in the pitch direction and the yaw direction relative to the input shaft 21.

[0145] Even when the configuration of the fourth embodiment is adopted, the transmission shaft 33 rotates around the rotation axis J3 and the input shaft 21 rotates around the rotation axis J1 in accordance with the rotation of the output shaft 14 around the motor rotation axis J2. Therefore, similar to the first to third embodiments, the drive unit 208 can transmit the driving force (rotational force) of the output unit 1 to the drive unit 2 via the transmission mechanism 3, and drive the sprocket 203.

[0146] <5. Remarks> The embodiments of the present invention have been described above. It should be noted that the embodiments described above are illustrative, and various modifications are possible in the combination of each component and each process, and this will be understood by those skilled in the art as being within the scope of the present invention.

[0147] For example, the configurations described in the first to fourth embodiments can be combined in accordance with the spirit of the present invention, as long as no particular contradictions arise.

[0148] <6. Summary> The embodiments described above will be summarized below.

[0149] For example, the work machine 100 disclosed herein is A work machine 100 comprising a traveling body 200 that is movable by drive wheels 203 mounted on side frames 2012 connected to the lower side of a center frame 2011, Supported by the aforementioned center frame 2011, the output unit 1 outputs the driving force of the electric motor 11, A transmission mechanism 3 that transmits the driving force from the output unit 1 to the drive wheel 203 side, It has, The transmission mechanism 3 has a transmission shaft portion 33 that extends downward from the output portion 1 towards the drive wheel 203 (first configuration).

[0150] The work machine 100 of the first configuration described above is The transmission shaft portion 33 may also be configured to extend further outward in the front-rear direction (for example, to the rear in Figure 3) as it moves from the output portion 1 side toward the drive wheel 203 side (second configuration).

[0151] Furthermore, the work machine 100 having the first or second configuration described above, The output unit 1 has an output shaft 14 that outputs the driving force to the transmission mechanism 3. The output shaft portion 14 may be configured to extend in a direction parallel to the rotation axis J1 of the drive wheel 203 (third configuration).

[0152] Furthermore, the work machine 100 having any of the above configurations from the first to the third is, The transmission mechanism 3 is The first bevel gear 31 is mounted on the output section 1 side of the transmission shaft section 33, The second bevel gear 32 is mounted on the drive wheel 203 side of the transmission shaft portion 33, It may also be a configuration that further includes (a fourth configuration).

[0153] Furthermore, the work machine 100 of the fourth configuration described above is The system further includes a drive unit 2 that drives the drive wheel 203, The output unit 1 is, The output shaft portion 14 outputs the aforementioned driving force to the transmission mechanism 3, A third bevel gear 15 is mounted on the output shaft portion 14 and meshes with the first bevel gear 31, It has, The drive unit 2 is The input shaft portion 21 to which the driving force is transmitted from the transmission mechanism 3, A fourth bevel gear 22 is mounted on the input shaft portion 21 and meshes with the second bevel gear 32, It may also be a configuration having (the fifth configuration).

[0154] Furthermore, the work machine 100 having the first or second configuration described above, The output unit 1 has an output shaft 14 that outputs the driving force to the transmission mechanism 3. The output shaft portion 14 and the transmission shaft portion 33 may be configured to extend along the same axis J4 (sixth configuration).

[0155] Furthermore, the work machine 100 having the first or second configuration described above, The rotating shaft J5 of the electric motor 11 may be configured to extend in a direction perpendicular to the vertical direction and the direction in which the rotating shaft J1 of the drive wheel 203 extends (seventh configuration).

[0156] Furthermore, the work machine 100 having any of the above configurations 1 to 7 is, First reduction gears 13, 24 increase the driving force by reducing the speed at a predetermined reduction ratio, The first braking devices 12 and 23 are positioned between the electric motor 11 and the first reduction gears 13 and 24 in the power transmission path, and suppress or prevent the transmission of power from the electric motor 11 to the first reduction gears 13 and 24. It may also be a configuration that further includes (the eighth configuration).

[0157] Furthermore, the work machine 100 having any of the above configurations 1 to 8 is, The output unit 1 may also have a configuration (the ninth configuration) that includes a second reduction gear 13 that increases the driving force output from the electric motor 11 by reducing it at a predetermined reduction ratio and outputs it to the transmission mechanism 3.

[0158] Furthermore, the work machine 100 having any of the above configurations 1 to 9 is, The system further includes a drive unit 2 that drives the drive wheel 203, The drive unit 2 may further include a third reduction gear 24 that increases the driving force transmitted from the transmission mechanism 3 by reducing it at a predetermined reduction ratio and outputs it to the drive wheel 203 (the tenth configuration).

[0159] Furthermore, the work machine 100 having any of the above configurations 1 to 10 is, The system further includes a drive unit 2 that drives the drive wheel 203, The drive unit 2 may also have a configuration (the 11th configuration) that further includes a second brake device 23 positioned between the transmission mechanism 3 and the drive wheel 203 in the driving force transmission path, which suppresses or prevents the transmission of the driving force to the drive wheel 203. [Industrial applicability]

[0160] This invention can be used, for example, in work machinery such as construction machinery and agricultural machinery. [Explanation of Symbols]

[0161] 100...Hydraulic excavator (working machine), 200...Lower chassis (working body), 201...Track frame, 2011...Center frame, 2012...Side frame, 2013...Link frame, 202...Idler, 203...Sprocket (drive wheel), 204...Upper roller, 205...Lower roller, 206...Crawler, 207...Retaining member, 208...Drive unit, 300...Working machine, 301... ...Boom, 3011...Boom cylinder, 302...Arm, 3021...Arm cylinder, 303...Bucket, 3031...Bucket cylinder, 400...Upper slewing body, 401...Control unit, 4011...Driver's seat, 402...Aircraft frame, 403...Slewing motor, 404...Engine room, 405...Bonnet, 406...Battery unit, 407...Motor, 4081...Hydraulic pump, 4082 ...Reservoir, 4083...Control valve, 4084...Hydraulic actuator, 4085...Hydraulic motor, 1...Output section, 11...Electric motor, 12...Brake device (first brake device), 13...Reduction gear (first reduction gear, second reduction gear), 14...Output shaft section, 15...Output gear (third bevel gear), 16...Output cover, 161...Opening, 2...Drive section, 21...Input shaft section, 22...Passive gear (fourth 23. Bevel gear, 24. Brake device (first brake device, second brake device), 25. Reducer (first reducer, third reducer), 26. Drive shaft, 27. Drive bearing, 27. Input cover, 271. Opening, 3. Transmission mechanism, 31. First transmission gear (first bevel gear), 32. Second transmission gear (second bevel gear), 33. Transmission shaft, 34. Transmission cover, 35. Transmission gear, 41, 42. Universal joint

Claims

1. A work machine comprising a traveling body that is propelled by drive wheels mounted on side frames connected to the lower side of the center frame, Supported by the aforementioned center frame, the output unit outputs the driving force of the electric motor, A transmission mechanism that transmits the driving force from the output unit to the drive wheel side, It has, The transmission mechanism is a working machine having a transmission shaft that extends downward from the output side toward the drive wheel side.

2. The work machine according to claim 1, wherein the transmission shaft portion extends further outward in the front-rear direction as it moves from the output portion side toward the drive wheel side.

3. The output unit has an output shaft that outputs the driving force to the transmission mechanism, The work machine according to claim 1 or claim 2, wherein the output shaft portion extends in a direction parallel to the rotation axis of the drive wheel.

4. The aforementioned transmission mechanism is A first bevel gear is mounted on the output side of the transmission shaft portion, The second bevel gear is mounted on the drive wheel side of the transmission shaft, The work machine according to claim 1 or claim 2, further comprising the above.

5. The system further includes a drive unit that drives the aforementioned drive wheels, The output section is, An output shaft portion that outputs the aforementioned driving force to the transmission mechanism, A third bevel gear is mounted on the output shaft and meshes with the first bevel gear, It has, The aforementioned drive unit is The input shaft portion to which the driving force is transmitted from the transmission mechanism, A fourth bevel gear is mounted on the input shaft and meshes with the second bevel gear, The work machine according to claim 4, having the following features.

6. The output unit has an output shaft that outputs the driving force to the transmission mechanism, The work machine according to claim 1 or claim 2, wherein the output shaft portion and the transmission shaft portion extend along the same axis.

7. The working machine according to claim 1 or claim 2, wherein the rotating shaft of the electric motor extends in a direction perpendicular to the vertical direction and the direction in which the rotating shaft of the drive wheel extends.

8. A first reduction gear that increases the driving force by reducing the speed at a predetermined reduction ratio, A first brake device is positioned between the electric motor and the first reduction gear in the power transmission path, and suppresses or prevents the transmission of power from the electric motor to the first reduction gear. The work machine according to claim 1 or claim 2, further comprising the above.

9. The work machine according to claim 1 or 2, wherein the output unit has a second reduction gear that increases the driving force output from the electric motor by reducing it at a predetermined reduction ratio and outputs it to the transmission mechanism.

10. The system further includes a drive unit that drives the aforementioned drive wheels, The work machine according to claim 1 or 2, wherein the drive unit further comprises a third reduction gear that increases the driving force transmitted from the transmission mechanism by reducing it at a predetermined reduction ratio and outputs it to the drive wheel.

11. The system further includes a drive unit that drives the aforementioned drive wheels, The work machine according to claim 1 or claim 2, wherein the drive unit further comprises a second brake device disposed between the transmission mechanism and the drive wheel in the driving force transmission path, for suppressing or preventing the transmission of the driving force to the drive wheel.

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