Work Machine

Abstract

To provide a work machine in which a motor can be appropriately arranged for generating driving force to drive working equipment.SOLUTION: An electric shovel includes a vehicle body frame 3, working equipment 10, a motor 30, and a power transmission device 40, the working equipment 10 including a boom 11 supported by the vehicle body frame 3, and a bucket 13 movable relative to the boom 11, the motor 30 being mounted on the vehicle body frame 3. The motor 30 generates driving force to move the bucket 13 relative to the boom 11. The power transmission device 40 mechanically transmits the driving force generated by the motor 30 to the bucket 13.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to work machines. [Background technology]

[0002] Japanese Patent Laid-Open Publication No. 2015-190587 (Patent Document 1) discloses a hydraulic excavator equipped with a front working mechanism. The front working mechanism includes a boom, an arm, and a bucket. The boom is driven by a boom cylinder. The arm is driven by an arm cylinder. A hydraulic pump is driven by an electric motor, and hydraulic oil discharged from the hydraulic pump is supplied to the arm cylinder, causing the arm cylinder to extend and retract. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2015-190587 A Summary of the Invention [Problem to be solved by the invention]

[0004] 2. Description of the Related Art In a work machine equipped with a work implement, when a driving force for driving the work implement is generated by an electric motor, it is necessary to appropriately position the electric motor.

[0005] The present disclosure proposes a work machine in which an electric motor that generates driving force for driving the work machine can be appropriately arranged. [Means for solving the problem]

[0006] A work machine according to the present disclosure includes a vehicle body frame, a work implement, an electric motor, and a power transmission device. The work implement includes a boom supported by the vehicle body frame and an attachment movable relative to the boom. The electric motor is mounted on the vehicle body frame. The electric motor generates a driving force that moves the attachment relative to the boom. The power transmission device mechanically transmits the driving force generated by the electric motor to the attachment. Effect of the Invention

[0007] According to the present disclosure, it is possible to appropriately arrange an electric motor that generates driving force for driving a working implement of a work machine. [Brief description of the drawings]

[0008] [Figure 1] 1 is a side view showing generally the configuration of a work machine based on a first embodiment. [Diagram 2] FIG. [Diagram 3] FIG. 4 is a first diagram showing an excavation operation by the work machine. [Figure 4] FIG. 4 is a second diagram showing the excavation operation by the work machine. [Diagram 5] FIG. 11 is a third diagram showing an excavation operation by the work machine. [Figure 6] FIG. 11 is a side view showing generally the configuration of a work machine based on a second embodiment. [Figure 7] FIG. 11 is a plan view showing generally the configuration of a work machine based on a third embodiment. [Figure 8] FIG. 11 is a side view showing generally the configuration of a work machine based on a fourth embodiment. [Figure 9] FIG. 13 is a side view showing generally the configuration of a work machine based on a fifth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment will be described with reference to the drawings. In the following description, the same components are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

[0010] In the following description, the terms "up," "down," "front," "rear," "left," and "right" are directions based on the operator seated in the driver's seat 4S in the driver's cab 4.

[0011] [First embodiment] <Overall composition> Fig. 1 is a side view showing a schematic configuration of an electric shovel 100 as an example of a work machine based on a first embodiment. Fig. 1 shows a schematic configuration of the electric shovel 100 as viewed from the right. As shown in Fig. 1, the electric shovel 100 of the embodiment mainly has a revolving body 2, a running body 5, and a working machine 10. The revolving body 2 and the running body 5 form a vehicle body 1 of the electric shovel 100.

[0012] The running body 5 has a pair of left and right track belt devices 5Cr. Each of the pair of left and right track belt devices 5Cr has a track. The pair of left and right track belts are rotationally driven to self-propel the electric excavator 100. The running body 5 may have wheels (tires) instead of the track belt devices 5Cr.

[0013] The rotating body 2 is installed so as to be freely rotatable with respect to the traveling body 5. The rotating body 2 mainly has a vehicle body frame 3, an operator's cab (cab) 4, and a counterweight 6. The operator's cab 4 and the counterweight 6 are mounted on the vehicle body frame 3.

[0014] An operator sits in the cab 4 to operate the electric shovel 100. The cab 4 is disposed, for example, on the front left side (front side of the vehicle) of the rotating body 2. A cab 4S for the operator to sit in is disposed in the internal space of the cab 4. In the present disclosure, the electric shovel 100 is operated from within the cab 4, but the electric shovel 100 may also be remotely operated wirelessly from a location away from the electric shovel 100. The counterweight 6 is disposed on the rear side of the rotating body 2 (rear side of the vehicle) relative to the cab 4. The counterweight 6 is disposed at the rear of the rotating body 2.

[0015] The work machine 10 is supported by the rotating body 2 at a front portion of the rotating body 2, for example, to the right of the operator's cab 4. The work machine 10 has a boom 11, an arm 12, and a bucket 13.

[0016] The base end of the boom 11 is rotatably connected to the rotating body 2 by a boom foot pin 15. The boom foot pin 15 extends in the left-right direction and passes through the base end of the boom 11. The base end of the arm 12 is rotatably connected to the tip of the boom 11 by an arm connecting pin 16. The arm connecting pin 16 extends in the left-right direction and passes through the tip of the boom 11 and the base end of the arm 12. The bucket 13 is rotatably connected to the tip of the arm 12 by an attachment connecting pin 17. The attachment connecting pin 17 extends in the left-right direction and passes through the tip of the arm 12 and the base end of the bucket 13.

[0017] The bucket 13 constitutes the tip portion of the work machine 10. The bucket 13 in this embodiment is connected to the boom 11 via the arm 12. The bucket 13 moves relative to the boom 11 as the bucket 13 rotates about the attachment connecting pin 17 and / or the arm 12 rotates about the arm connecting pin 16. The bucket 13 is configured to be movable relative to the boom 11.

[0018] Bucket 13 has a plurality of blades. The tip of bucket 13 is referred to as cutting edge 13A. Bucket 13 does not necessarily have to have a blade. The tip of bucket 13 may be formed of a straight steel plate. Bucket 13 of the embodiment has neck 13B between its main body and attachment connecting pin 17, which is formed to be thinner than the main body.

[0019] The bucket 13 is an example of an attachment that is detachably attached to the tip of the work machine 10 and is rotatable with respect to the arm 12. Depending on the type of work, the attachment can be changed to a breaker, a grapple, a lifting magnet, or the like.

[0020] FIG. 2 is a plan view of the vehicle body frame 3. The vehicle body frame 3 has a pair of left and right vertical plates 7, 8. The vertical plates 7, 8 extend in the front-rear direction (the up-down direction in FIG. 2). The vertical plates 7, 8 are arranged at an interval in the width direction (left-right direction) of the rotating body 2. The vertical plates 7, 8 are composed of plates standing in the up-down direction, and are arranged at a distance from each other in the left-right direction. The operator's cab 4 is arranged to the left of the left vertical plate 7. The working machine 10 is arranged between the vertical plates 7, 8 in the left-right direction. The working machine 10 is arranged to the right of the left vertical plate 7 and to the left of the right vertical plate 8.

[0021] <Electric motor 30> In the electric shovel 100 of the embodiment, the electric motor 30 generates driving force for driving the work machine 10. The electric motor 30 is capable of driving the work machine 10. The boom 11, the arm 12, and the bucket 13 are each driven by the electric motor 30, thereby enabling the work machine 10 to operate.

[0022] The electric motor 30 is mounted on the vehicle body frame 3. The electric motor 30 has a boom motor 31, an arm motor 32, and an attachment motor 33. The boom motor 31, the arm motor 32, and the attachment motor 33 are all mounted on the vehicle body frame 3. The boom motor 31, the arm motor 32, and the attachment motor 33 may be geared motors integrated with reduction gears.

[0023] The boom electric motor 31 drives the boom 11 and generates a driving force for moving the boom 11 relative to the vehicle body frame 3. Driven by the boom electric motor 31, the boom 11 can rotate relatively to the vehicle body frame 3 about the boom foot pin 15. The boom foot pin 15 is disposed across both the left and right vertical plates 7, 8. The left end of the boom foot pin 15 is supported by the left vertical plate 7, and the right end of the boom foot pin 15 is supported by the right vertical plate 8. As a result, the boom 11 is supported by the vehicle body frame 3 so as to be rotatable about the boom foot pin 15.

[0024] The arm motor 32 drives the arm 12 and generates a driving force for moving the arm 12 relative to the boom 11. The arm 12 is driven by the arm motor 32 to be rotatable relative to the boom 11 about the arm connecting pin 16.

[0025] The attachment electric motor 33 drives the bucket 13 to generate a driving force for moving the bucket 13 relative to the arm 12 and relative to the boom 11. Driven by the attachment electric motor 33, the bucket 13 can rotate relative to the arm 12 about the attachment connecting pin 17.

[0026] Boom 11 is heavier than arm 12, which is heavier than bucket 13. The rated output of boom motor 31 that drives boom 11, which is a heavy object, is greater than the rated output of arm motor 32 that drives arm 12. The rated output of arm motor 32 is greater than the rated output of attachment motor 33 that drives bucket 13, which is lighter in weight. Here, the rated output of a motor refers to the maximum output that the motor can safely achieve under specified conditions.

[0027] 2 are all mounted on the vehicle body frame 3 and disposed at the base end of the work machine 10 (the base end of the boom 11). The boom motor 31, the arm motor 32 and the attachment motor 33 may be disposed concentrically with the boom foot pin 15. One or more of the output shaft 34 of the boom motor 31, the output shaft 35 of the arm motor 32 and the output shaft 36 of the attachment motor 33 may extend in the left-right direction and may be disposed in a straight line with the boom foot pin 15.

[0028] <Power transmission device 40> The electric shovel 100 of the embodiment includes a power transmission device 40 that mechanically transmits the driving force generated by the electric motor 30 to the work machine 10. The power transmission device 40 will be described with reference to Figs.

[0029] The output shaft 34 of the boom motor 31 is connected to the base end of the boom 11. The driving force generated by the boom motor 31 is transmitted to the boom 11 via the output shaft 34. As a result, the boom 11 is driven to rotate around the boom foot pin 15.

[0030] The power transmission device 40 has an arm rotating member 51 and an arm link member 53. The output shaft 35 of the arm electric motor 32 is connected to the arm rotating member 51. The arm rotating member 51 is disposed at the base end of the boom 11. The arm rotating member 51 receives the driving force of the arm electric motor 32 and can rotate about the connection point with the output shaft 35. The arm rotating member 51 extends forward and downward from the connection point with the output shaft 35. The arm link member 53 has a rod-like shape. The arm link member 53 is connected at a first end thereof to the arm rotating member 51 via a connection pin 56. The arm link member 53 is connected at a second end thereof to the arm 12 via a connection pin 57.

[0031] 1, the arm link member 53 is connected to the arm 12 between the arm connecting pin 16 and the attachment connecting pin 17. The arm link member 53 is connected to the arm 12 at a position closer to the arm connecting pin 16 and farther from the attachment connecting pin 17 in the longitudinal direction of the arm 12. The distance between the connecting pin 57 and the arm connecting pin 16 is smaller than the distance between the connecting pin 57 and the attachment connecting pin 17.

[0032] The arm rotating member 51 , the arm link member 53 and the connecting pins 56 , 57 constitute an arm power transmission device that mechanically transmits the driving force generated by the arm electric motor 32 to the arm 12 .

[0033] The power transmission device 40 has an attachment rotating member 61, an intermediate member 62, a first attachment link member 63, and a second attachment link member 64. The output shaft 36 of the attachment electric motor 33 is connected to the attachment rotating member 61. The attachment rotating member 61 is disposed at the base end of the boom 11. The attachment rotating member 61 receives the driving force of the attachment electric motor 33 and is rotatable about the connection point with the output shaft 36. The attachment rotating member 61 extends downward and forward from the connection point with the output shaft 36.

[0034] The intermediate member 62 is supported by the arm 12 via a support pin 65 so as to be rotatable relative to both the boom 11 and the arm 12. The support pin 65 shown in Figures 1 and 2 extends in the left-right direction and is disposed concentrically with the arm connecting pin 16. The support pin 65 may be connected to the arm 12 at a position deviated from the arm connecting pin 16.

[0035] The first attachment link member 63 has a rod-like shape. A first end of the first attachment link member 63 is connected to the attachment rotating member 61 via a connecting pin 66. A second end of the first attachment link member 63 is connected to the intermediate member 62 via a connecting pin 67.

[0036] The second attachment link member 64 has a rod-like shape. A first end of the second attachment link member 64 is connected to the intermediate member 62 via a connecting pin 68. A second end of the second attachment link member 64 is connected to the bucket 13 via a connecting pin 69. The connecting pin 69 may be disposed in the neck portion 13B of the bucket 13.

[0037] The second attachment link member 64 is connected to the intermediate member 62 at a position farther from the attachment connecting pin 17 than the position at which the first attachment link member 63 is connected to the intermediate member 62. Therefore, in the side view shown in Figure 1, the first attachment link member 63 and the second attachment link member 64 cross each other.

[0038] The intermediate member 62 may have a generally polygonal shape. The support pin 65 and the connecting pins 66 and 67 may be connected to the intermediate member 62 near different vertices of the generally polygonal shape.

[0039] The attachment rotating member 61, the intermediate member 62, the first attachment link member 63, the second attachment link member 64, the support pin 65, and the connecting pins 66, 67, 68, 69 constitute an attachment power transmission device that mechanically transmits the driving force generated by the attachment electric motor 33 to the bucket 13.

[0040] 2, the power transmission device 40 is disposed on the opposite side of the cab 4 with respect to the work machine 10. In the configuration of the embodiment in which the cab 4 is disposed on the front left side on the body frame 3 and the cab 4 is disposed on the left side with respect to the work machine 10, the power transmission device 40 is disposed on the right side with respect to the work machine 10.

[0041] <Excavation Operation by Working Machine 10> An explanation will now be given of the excavation operation performed by the work machine 10 of the electric shovel 100 having the above-mentioned configuration.

[0042] In the posture of the work machine 10 shown in Fig. 3, the cutting edge 13A of the bucket 13 is in contact with the ground. From this state, the boom 11 is raised, the arm 12 is moved in the excavation direction (the direction in which the arm 12 approaches the boom 11), and the bucket 13 is moved in the excavation direction (the direction in which the cutting edge 13A of the bucket 13 approaches the arm 12), thereby resulting in the posture shown in Fig. 4. By further raising the boom 11, moving the arm 12 in the excavation direction, and moving the bucket 13 in the excavation direction, the posture shown in Fig. 5 is obtained. By moving the work machine 10 in this manner, an excavation operation is performed in which the object to be excavated, such as soil and sand, is scooped up into the bucket 13.

[0043] 3 to 5 causes bucket 13 to move closer to body frame 3. During excavation operation, arm link member 53, first attachment link member 63 and second attachment link member 64 are subjected to a tensile force.

[0044] 3 to 5, a force acts on the arm link member 53 in a direction pulling the arm link member 53 towards the base end connected to the arm rotating member 51. In this way, a tensile force acts on the arm link member 53, so that the arm 12 moves in the excavation direction and approaches the boom 11.

[0045] 3 to 5, a force acts on the first attachment link member 63 in a direction pulling the first attachment link member 63 towards the base end connected to the attachment rotating member 61. In response to the movement of the first attachment link member 63, the intermediate member 62 rotates around the support pin 65 in a clockwise direction in FIGS. 3 to 5. As the intermediate member 62 rotates, a force acts on the second attachment link member 64 in a direction pulling the second attachment link member 64 towards the base end connected to the intermediate member 62. In this way, a tensile force acts on the first attachment link member 63 and the second attachment link member 64, causing the bucket 13 to move in the excavation direction, and the bucket 13 approaches the vehicle body frame 3.

[0046] <Action and Effects> Although some of the description herein overlaps with the above description, the characteristic configuration and effects of this embodiment can be summarized as follows.

[0047] 2, the electric shovel 100 includes an electric motor 30 that generates driving force to drive the work machine 10. By driving the work machine 10 electrically rather than by a hydraulic cylinder, it is possible to reduce power, reduce the effects of fluctuations in hydraulic pressure, reduce the effects of changes in dynamic viscosity characteristics due to temperature changes in the hydraulic oil, and reduce noise generated during work.

[0048] As shown in Fig. 2, the electric motor 30 is mounted on the vehicle body frame 3. An arm electric motor 32 that drives the arm 12 at the tip of the boom 11 is not mounted on the boom 11, but is mounted on the vehicle body frame 3. An attachment electric motor 33 that drives the bucket 13 at the tip of the arm 12 is not mounted on the arm 12, but is mounted on the vehicle body frame 3. By not mounting heavy objects on the work machine 10, the weight of the work machine 10 can be reduced. By mounting heavy objects on the vehicle body frame 3, the stability of the electric excavator 100 can be increased.

[0049] By locating electric motor 30 in a position away from bucket 13, which is subjected to a load during work, it is possible to reduce the impact transmitted to electric motor 30, thereby improving the reliability of electric motor 30. When dredging the bottom of a river, harbor, etc., bucket 13 and arm 12 will move into the water, but since electric motor 30 mounted on body frame 3 does not need to be considered for being submerged, electric motor 30 can be configured simply.

[0050] As shown in Figs. 1 and 2, the electric shovel 100 is equipped with a power transmission device 40. The power transmission device 40 mechanically transmits the driving force generated by the electric motor 30 to the work machine 10. By mechanically transmitting the driving force of the electric motor 30 to the work machine 10 without converting it into hydraulic power, the amount of power consumed by the electric motor 30 can be reduced. This makes it possible to reduce the capacity of the battery mounted on the vehicle body frame 3, thereby improving the space efficiency on the vehicle body frame 3. Furthermore, the manufacturing costs and maintenance costs of the electric shovel 100 can be reduced by the amount of the battery reduction.

[0051] As shown in Figs. 1 and 2, the power transmission device 40 has a rod-shaped arm link member 53, a rod-shaped first attachment link member 63, and a rod-shaped second attachment link member 64. As shown in Figs. 3 to 5, a tensile force is applied to the arm link member 53, the first attachment link member 63, and the second attachment link member 64, thereby moving the bucket 13 closer to the vehicle body frame 3. By configuring the link members so that no compressive force is applied to them during excavation work, which places a relatively large load on the work machine 10, buckling of the rod-shaped link members can be suppressed. Since it is not necessary to increase the rigidity of the link members to prevent buckling, and link members with smaller diameters can be used, the weight of the work machine 10 can be reduced.

[0052] As shown in FIG. 2, the power transmission device 40 is disposed on the opposite side of the cab 4 with respect to the work machine 10. This allows the power transmission device 40 to be disposed freely without interfering with the cab 4. The movement of the power transmission device 40 is not hindered by the cab 4, and the power transmission device 40 can reliably transmit the driving force of the electric motor 30 to the work machine 10. By disposing the power transmission device 40 so as not to be interposed between the cab 4 and the power transmission device 40, the operator in the cab 4 can visually check the work machine 10 without being hindered by the power transmission device 40. By improving the visibility of the work machine 10, it becomes possible to perform work using the work machine 10 more easily.

[0053] 2, the electric motor 30 is disposed at the base end of the work machine 10. By disposing it in this manner, it is possible to simplify the structure of the power transmission device 40 that transmits driving force from the electric motor 30 to the work machine 10. Since the path for transmitting power from the electric motor 30 to the work machine 10 can be shortened, it is possible to improve the power transmission efficiency.

[0054] The boom 11 is heavier than the bucket 13. By making the rated output of the boom motor 31 that drives the boom 11 greater than the rated output of the attachment motor 33 that drives the bucket 13, it becomes possible to reliably drive the heavy boom 11, and also to make the attachment motor 33 more compact and less costly.

[0055] 1 and 2, the power transmission device 40 has an arm rotating member 51 that is arranged at the base end of the boom 11 and can rotate by receiving the driving force of the arm electric motor 32, and a rod-shaped arm link member having one end connected to the arm rotating member 51 and the other end connected to the arm 12. The driving force generated by the arm electric motor 32 can be reliably transmitted to the arm 12 via the arm rotating member 51 and the arm link member 53.

[0056] 1 and 2, the arm link member 53 is connected to the arm 12 between the arm connecting pin 16 and the attachment connecting pin 17. This ensures that a tensile force is applied to the rod-shaped arm link member 53 during excavation work.

[0057] 1 and 2, the power transmission device 40 has an attachment rotating member 61 that is arranged at the base end of the boom 11 and rotatable by receiving the driving force of the attachment electric motor 33, an intermediate member 62 that is supported by the arm 12 so as to be rotatable relative to the boom 11 and the arm 12, a rod-shaped first attachment link member 63 having one end connected to the attachment rotating member 61 and the other end connected to the intermediate member 62, and a rod-shaped second attachment link member 64 having one end connected to the intermediate member 62. The driving force generated by the attachment electric motor 33 can be reliably transmitted to the bucket 13 via the attachment rotating member 61, the first attachment link member 63, the intermediate member 62, and the second attachment link member 64.

[0058] 1 and 2, the other end of the second attachment link member 64 is connected to the bucket 13. By directly connecting the second attachment link member 64 to the bucket 13, the configuration of the power transmission device 40 can be simplified.

[0059] 1 and 2, the second attachment link member 64 is connected to the intermediate member 62 at a position farther from the attachment connecting pin 17 than the position at which the first attachment link member 63 is connected to the intermediate member 62. This ensures that a tensile force is applied reliably to the rod-shaped first attachment link member 63 and second attachment link member 64 during excavation work.

[0060] [Second embodiment] 6 is a side view showing a schematic configuration of a work machine according to a second embodiment. In an electric excavator 100 of the second embodiment, a work machine 10 has a bucket link 21. The bucket link 21 has a first link member 22 and a second link member 23. The first link member 22 and the second link member 23 are connected to each other so as to be capable of relative rotation. The first link member 22 and the second link member 23 are connected to each other by a link pin 24. The first link member 22 is rotatably connected to the arm 12 by a link pin 25. The second link member 23 is rotatably connected to a bracket at the base of the bucket 13 by a link pin 26.

[0061] The first link member 22 has a rod-like shape. One end of the first link member 22 is connected to the second link member 23, and the center portion of the first link member 22 is connected to the arm 12. The other end of the first link member 22 is connected to the second attachment link member 64 by a connecting pin 69.

[0062] During the excavation operation, the intermediate member 62 rotates clockwise in FIG. 6 around the support pin 65. As the intermediate member 62 rotates, a force acts on the second attachment link member 64 in a pulling direction toward the base end connected to the intermediate member 62. In response to the movement of the second attachment link member 64, the first link member 22 rotates clockwise in FIG. 6 around the link pin 25. As the first link member 22 rotates, a force acts on the second link member 23 in a pushing direction from one end connected to the first link member 22 toward the other end connected to the bucket 13. This causes the bucket 13 to move in the excavation direction.

[0063] Instead of the configuration in which the second attachment link member 64 is directly connected to the bucket 13 as described in the first embodiment, the second attachment link member 64 can be connected to the bucket link 21. In this case as well, the driving force generated by the attachment electric motor 33 can be reliably transmitted to the bucket 13 via the bucket link 21. Since the angle of relative rotation of the bucket 13 with respect to the arm 12 can be increased, work using the work machine 10 can be performed more easily. By forming the bucket 13 in a shape that does not have a neck portion 13B, the strength of the bucket 13 can be improved.

[0064] [Third embodiment] 7 is a plan view showing a schematic configuration of a work machine according to the third embodiment. In an electric shovel 100 of the third embodiment, a power transmission device 40 has a power transmission mechanism 45 on a power transmission path from the arm motor 32 to the arm 12, a power transmission mechanism 46 on a power transmission path from the attachment motor 33 to the bucket 13, and a power transmission mechanism 47 on a power transmission path from the boom motor 31 to the boom 11.

[0065] More specifically, a boom rotating member 71 is fixed to a side surface of the boom 11. The driving force generated by the boom electric motor 31 is transmitted from the output shaft 34 to the power transmission mechanism 47, and then transmitted from the power transmission mechanism 47 to the boom rotating member 71. The boom rotating member 71 rotates upon receiving the driving force of the boom electric motor 31. This causes the boom 11 to rotate around the boom foot pin 15.

[0066] The driving force generated by the arm motor 32 is transmitted from the output shaft 35 to the power transmission mechanism 45, and then from the power transmission mechanism 45 to the arm rotating member 51. The arm rotating member 51 rotates upon receiving the driving force of the arm motor 32. The driving force generated by the attachment motor 33 is transmitted from the output shaft 36 to the power transmission mechanism 46, and then from the power transmission mechanism 46 to the attachment rotating member 61. The attachment rotating member 61 rotates upon receiving the driving force of the attachment motor 33.

[0067] The power transmission mechanisms 45-47 may be any mechanism as long as they can transmit the rotational driving force generated by the electric motor 30 to the work machine 10. The power transmission mechanisms 45-47 may have a propeller shaft or a flexible shaft. The power transmission mechanisms 45-47 may have a belt and a pulley. The power transmission mechanisms 45-47 may achieve power transmission and deceleration by meshing of a plurality of gears.

[0068] The driving force of the electric motor 30 is transmitted to the work implement 10 via the power transmission mechanisms 45-47, which improves the degree of freedom in arranging the electric motor 30 on the body frame 3. If the electric motor 30 is arranged on the rear side of the body frame 3, opposite the front part of the body frame 3 that supports the work implement 10, the counterweight 6 (FIG. 1) can be reduced by an amount corresponding to the weight of the electric motor 30.

[0069] [Fourth embodiment] 8 is a side view showing a schematic configuration of a work machine according to a fourth embodiment. In an electric shovel 100 according to the fourth embodiment, a first attachment link member 63 is connected to an intermediate member 62. A second attachment link member 64 is connected to the intermediate member 62. The second attachment link member 64 is connected to the intermediate member 62 at a position closer to the attachment connecting pin 17 than the position at which the first attachment link member 63 is connected to the intermediate member 62.

[0070] Even with this configuration, the driving force generated by the attachment electric motor 33 can be reliably transmitted to the bucket 13 via the attachment rotating member 61, the first attachment link member 63, the intermediate member 62, and the second attachment link member 64.

[0071] In the case of the fourth embodiment, as the attachment rotating member 61 rotates counterclockwise in Fig. 8, a force acts on the first attachment link member 63 in a pushing direction from the base end connected to the attachment rotating member 61 toward the tip end connected to the intermediate member 62. This causes the intermediate member 62 to rotate clockwise in Fig. 8 around the support pin 65. Therefore, in the case of the fourth embodiment, a compressive force acts on the rod-shaped first attachment link member 63 during excavation work.

[0072] [Fifth embodiment] FIG. 9 is a side view showing a schematic configuration of a work machine according to a fifth embodiment. In an electric excavator 100 according to the fifth embodiment, an attachment rotating member 61 extends rearward and upward from a connection point with the output shaft 36. A first attachment link member 63 is connected to the intermediate member 62 above a support pin 65. A second attachment link member 64 is connected to the intermediate member 62 above a support pin 65. The bucket 13 has a neck portion 13B, which extends across both sides of the arm 12. At a middle portion of the neck portion 13B, the bucket 13 is connected to the arm 12 by an attachment connecting pin 17. At a tip portion of the neck portion 13B, the second attachment link member 64 is connected to the bucket 13 by a connecting pin 69.

[0073] Even with this configuration, the driving force generated by the attachment electric motor 33 can be reliably transmitted to the bucket 13 via the attachment rotating member 61, the first attachment link member 63, the intermediate member 62, and the second attachment link member 64.

[0074] In the case of the fifth embodiment, as a result of the attachment rotating member 61 rotating in the clockwise direction in Fig. 9, a force acts on the first attachment link member 63 in a direction pushing the first attachment link member 63 from the base end connected to the attachment rotating member 61 toward the tip end connected to the intermediate member 62. As a result, the intermediate member 62 rotates in the clockwise direction in Fig. 8 around the support pin 65. As a result of the intermediate member 62 rotating, a force acts on the second attachment link member 64 in a direction pushing the second attachment link member 64 from the base end connected to the intermediate member 62 toward the tip end connected to the bucket 13. As a result, the bucket 13 rotates in the clockwise direction in Fig. 9 around the attachment connecting pin 17, and the bucket 13 moves in the excavation direction, and the cutting edge 13A of the bucket 13 approaches the vehicle body frame 3.

[0075] Therefore, in the case of the fifth embodiment, a compressive force acts on the rod-shaped first attachment link member 63 and second attachment link member 64 during excavation work.

[0076] In the above embodiment, an example has been described in which the power transmission device 40 has a rod-shaped link member. The power transmission device 40 may have a mechanism other than a link member as long as it can mechanically transmit the driving force of the electric motor 30 to the work machine 10. For example, the power transmission device 40 may have any one or a combination of a steel cable, a chain, a pulley, a rack and pinion, and the like.

[0077] In the embodiment, an example has been described in which the cab 4 is disposed on the front left side of the body frame 3, the work implement 10 is disposed to the right of the cab 4, and the power transmission device 40 is disposed to the right of the work implement 10. The arrangement is not limited to this, and for example, by disposing the cab 4 behind the work implement 10, it becomes possible to dispose the power transmission device 40 on both the left and right sides of the work implement 10, thereby improving the degree of freedom in disposing the power transmission device 40.

[0078] In the embodiment, an example has been described in which the electric motor 30 has the boom electric motor 31, the arm electric motor 32, and the attachment electric motor 33 separately. The electric motors 30 that generate driving forces for the boom 11, the arm 12, and the bucket 13 do not necessarily have to be provided separately. A configuration may be adopted in which power is distributed from the output shaft of a single electric motor 30 to transmit the driving force to the boom 11, the arm 12, and the bucket 13, respectively. In this case, the transmission of driving force to the boom 11, the arm 12, and the bucket 13 may be switched by an operation of an operator in the cab 4.

[0079] In the embodiment, the electric shovel 100 including the electric motor 30 that generates driving force for driving the work machine 10 has been described. The electric shovel 100 may be an electric vehicle in which the driving force for traveling of the traveling body 5 and for rotating the rotating body 2 relative to the traveling body 5 is also generated by the electric motor. The electric shovel 100 does not have to include an internal combustion engine. The electric shovel 100 does not have to include a hydraulic circuit.

[0080] In the embodiment, an electric shovel 100 is given as an example of a work machine, but the present invention is not limited to the electric shovel 100 and can be applied to other types of work machines equipped with articulated work implements such as wheel loaders.

[0081] Although the embodiments have been described above, configurations that can be combined with each other in each embodiment may be appropriately combined. In addition, the embodiments disclosed herein are illustrative in all respects and should not be considered as limiting. The scope of the present invention is indicated by the claims rather than the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0082] 1 vehicle body, 2 rotating body, 3 vehicle body frame, 4 driver's cab, 4S driver's seat, 5 running body, 5Cr track device, 10 work equipment, 11 boom, 12 arm, 13 bucket, 13A cutting edge, 13B neck, 15 boom foot pin, 16 arm connecting pin, 17 attachment connecting pin, 21 bucket link, 22 first link member, 23 second link member, 24, 25, 26 link pin, 30 electric motor, 31 boom electric motor, 32 arm electric motor, 33 attachment electric motor, 34, 35, 36 output shaft, 40 power transmission device, 45, 46, 47 power transmission mechanism, 51 arm rotating member, 53 arm link member, 56, 57, 66, 67, 68, 69 connecting pin, 61 attachment rotating member, 62 Intermediate member, 63 first attachment link member, 64 second attachment link member, 65 support pin, 71 boom rotating member, 100 electric excavator.

Claims

1. The vehicle frame, a working machine including a boom supported by the vehicle body frame and an attachment movable relative to the boom; an electric motor mounted on the vehicle body frame and configured to generate a driving force for moving the attachment relative to the boom; a power transmission device that mechanically transmits a driving force generated by the electric motor to the attachment, The power transmission device has a rod-shaped link member, A work machine in which the attachment is moved closer to the vehicle body frame by applying a tensile force to the link member.

2. a driver's cab mounted on the vehicle body frame, arranged to the side of the work machine, and in which an operator who operates the work machine sits; The work machine according to claim 1 , wherein the power transmission device is disposed on an opposite side of the operator's cab with respect to the work implement.

3. The work machine according to claim 1 or 2, wherein the electric motor is disposed at a base end of the boom.

4. a boom motor mounted on the vehicle body frame and generating a driving force for moving the boom relative to the vehicle body frame, The work machine according to claim 1 , wherein the rated output of the boom motor is greater than the rated output of the electric motor.

5. The work machine further includes an arm attached to a tip of the boom and an arm connecting pin supporting the arm so as to be rotatable relative to the boom, the work machine further includes an arm motor mounted on the vehicle body frame and generating a driving force for moving the arm relatively to the boom, and an arm power transmission device mechanically transmitting the driving force generated by the arm motor to the arm, 5. The work machine according to claim 1, wherein the arm power transmission device comprises: an arm rotating member that is disposed at a base end of the boom and is rotatable by receiving driving force from the arm electric motor; and a rod-shaped arm link member having one end connected to the arm rotating member and the other end connected to the arm.

6. The work machine further includes an attachment connecting pin that supports the attachment so as to be rotatable relative to the arm, The work machine according to claim 5 , wherein the arm link member is connected to the arm at a position between the arm connecting pin and the attachment connecting pin.

7. 7. The work machine according to claim 5 or claim 6, wherein the power transmission device comprises: an attachment rotating member that is arranged at a base end of the boom and can rotate by receiving driving force from the electric motor; an intermediate member supported by the arm so as to be rotatable relative to the boom and the arm; a rod-shaped first attachment link member having one end connected to the attachment rotating member and the other end connected to the intermediate member; and a rod-shaped second attachment link member having one end connected to the intermediate member.

8. 8. The work machine of claim 7, wherein the second attachment link member has an other end connected to the attachment.

9. The work machine further includes an attachment connecting pin that supports the attachment so as to be rotatable relative to the arm, 9. A work machine according to claim 7 or claim 8, wherein the second attachment link member is connected to the intermediate member at a position farther from the attachment connecting pin than a position at which the first attachment link member is connected to the intermediate member.

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