Electric work machine

Abstract

In the present invention, an electric shovel (1) comprises: a hydraulic pump (65) that discharges a hydraulic oil; an electric motor (64) that drives the hydraulic pump (65); a hydraulic oil tank (66) that supplies the hydraulic oil to the hydraulic pump (65); and a suction pipe (70) that is connected to the hydraulic pump (65) and the hydraulic oil tank (66) and extends along an output shaft (64a) of the electric motor (64). In a top view, the suction pipe (70) overlaps the electric motor (64).

Description

electric work machine

[0001] The present disclosure relates to electric work machines.

[0002] Patent Document 1 discloses an electric shovel as an example of an electric work machine. The electric shovel includes an electric motor driven by electricity stored in a battery device. The electric motor drives a hydraulic pump that supplies pressure oil to a hydraulic cylinder of the work machine.

[0003] Japanese Patent Application Laid-Open No. 2020-045630

[0004] In an electric work machine, a large battery must be placed in the center of the vehicle body, so it is preferable to appropriately arrange hydraulic equipment such as a hydraulic pump and an electric motor in a limited space.

[0005] An object of the present disclosure is to provide an electric work machine that allows a hydraulic pump and an electric motor to be appropriately arranged in a limited space.

[0006] An electric work machine according to the present disclosure includes a hydraulic pump that discharges hydraulic oil, an electric motor that drives the hydraulic pump, a hydraulic oil tank that supplies hydraulic oil to the hydraulic pump, and a suction pipe that is connected to the hydraulic pump and the hydraulic oil tank and extends along an output shaft of the electric motor. In a top view, the suction pipe overlaps with the electric motor.

[0007] According to the present disclosure, it is possible to provide an electric work machine in which a hydraulic pump and an electric motor can be appropriately arranged in a limited space.

[0008] Fig. 1 is a perspective view of an electric shovel according to an embodiment; Fig. 2 is a perspective view showing an internal configuration of a body cover according to an embodiment; Fig. 3 is a side view showing an internal configuration of a body cover according to an embodiment; Fig. 4 is a top view showing an internal configuration of a body cover according to an embodiment;

[0009] (Electric Shovel 1) The configuration of an electric shovel 1 (an example of an "electric work machine") according to this embodiment will be described with reference to the drawings.

[0010] FIG. 1 is a perspective view of an electric shovel 1 as seen from the right rear.

[0011] In this specification, "up" and "down" mean above and below based on the vertical direction, "front" and "rear" mean forward and rear based on the direction of travel of the electric shovel 1, and "left" and "right" mean left and right when facing forward of the electric shovel 1.

[0012] As shown in FIG. 1 , the electric excavator 1 includes a lower traveling body 2 , an upper rotating body 3 , a work machine unit 4 , and a cab 5 .

[0013] The undercarriage 2 has a track frame 20, driving wheels 21, driven wheels 22, and crawler belts 23. The track frame 20 extends in the front-to-rear direction. The driving wheels 21 are supported at the rear end of the track frame 20. The driven wheels 22 are supported at the front end of the track frame 20. The crawler belts 23 are stretched between the driving wheels 21 and the driven wheels 22.

[0014] The upper rotating body 3 is disposed above the lower traveling body 2. The upper rotating body 3 is rotatable relative to the lower traveling body 2. The upper rotating body 3 has a rotating frame 31 and a vehicle body cover 32.

[0015] The revolving frame 31 is formed in a plate shape that extends horizontally. The revolving frame 31 is supported by the lower traveling body 2. The revolving frame 31 is revolvable with respect to the lower traveling body 2.

[0016] The body cover 32 covers the space above the revolving frame 31. The body cover 32 is made of a plate-shaped member. The body cover 32 accommodates a battery device 61, a BTMS (battery thermal management system) 62, an inverter 63, an electric motor 64, a hydraulic pump 65, a hydraulic oil tank 66, a hydraulic valve 67, and the like.

[0017] 1, the hydraulic pump 65, the electric motor 64, and the hydraulic oil tank 66 are disposed on the opposite side of the cab 5 in the vehicle width direction. The hydraulic pump 65, the electric motor 64, and the hydraulic oil tank 66 are disposed in this order from rear to rear. The internal configuration of the body cover 32 will be described later.

[0018] The work implement unit 4 has a work implement 40 and a work implement drive section 41. The work implement 40 includes a boom 42, an arm 43, and a bucket 44. The work implement drive section 41 includes a boom cylinder 45, an arm cylinder 46, and a bucket cylinder 47. The boom cylinder 45, the arm cylinder 46, and the bucket cylinder 47 are operated by hydraulic oil supplied from a hydraulic valve 67.

[0019] The cab 5 is disposed on the left front end of the revolving frame 31. Various operating members and the like are disposed inside the cab 5.

[0020] (Internal Configuration of Body Cover 32) Fig. 2 is a perspective view of the internal configuration of the body cover 32 as seen from the front right. Fig. 3 is a side view of the internal configuration of the body cover 32 as seen from the right. Fig. 4 is a top view of the internal configuration of the body cover 32 as seen from above.

[0021] Inside the body cover 32, a battery device 61, a BTMS 62, an inverter 63, an electric motor 64, a hydraulic pump 65, a hydraulic oil tank 66, and a hydraulic valve 67 are arranged.

[0022] The battery device 61 is disposed on the rear end of the revolving frame 31. As shown in Figure 4, the battery device 61 is disposed approximately in the center of the revolving frame 31 in the vehicle width direction. The vehicle width direction is synonymous with the left-right direction. The battery device 61 supplies DC power to the inverter 63.

[0023] The battery system 61 includes multiple battery packs stacked vertically and a water jacket through which a heat transfer fluid circulates. Multiple batteries are arranged inside each battery pack. The heat transfer fluid circulates inside the water jacket, maintaining each battery within an appropriate temperature range (e.g., 20°C to 35°C). The battery system 61 also functions as a counterweight, which is provided in conventional hydraulic excavators.

[0024] The BTMS 62 is disposed above the battery device 61. The BTMS 62 manages the temperature of the battery device 61. The BTMS 62 supplies a heat transfer fluid for cooling or heating the battery device 61 to a water jacket of the battery device 61.

[0025] The inverter 63 is disposed in front of the battery device 61. The inverter 63 converts DC power supplied from the battery device 61 into AC power of a desired frequency. The inverter 63 is electrically connected to the electric motor 64 by a high-voltage cable 68. The inverter 63 supplies AC power to the electric motor 64 via the high-voltage cable 68. In this embodiment, two high-voltage cables 68 are used, but the number of high-voltage cables 68 can be changed as appropriate.

[0026] The electric motor 64 is disposed on a side end (the right end in this embodiment) of the revolving frame 31 , in front of the hydraulic pump 65 and behind the hydraulic oil tank 66 .

[0027] 3 and 4, the front end of the electric motor 64 is located rearward of the rotation center Ax of the upper rotating body 3. A line La indicating the position of the front end of the electric motor 64 in the fore-and-aft direction is a distance Da rearward from the rotation center Ax of the upper rotating body 3. The distance Da is not particularly limited and can be set to any value greater than 0.

[0028] The electric motor 64 is electrically connected to the inverter 63 via a high-voltage cable 68. The electric motor 64 is driven by AC power supplied from the inverter 63 via the high-voltage cable 68. Specifically, the electric motor 64 rotates a drive shaft 64a disposed along the front-rear direction. As shown in FIGS. 3 and 4 , the drive shaft 64a is connected to a rotary shaft 65a of a hydraulic pump 65 (described later). The electric motor 64 drives the hydraulic pump 65 by the rotation of the drive shaft 64a.

[0029] The electric motor 64 is fixed to the hydraulic pump 65 by a coupling 69. The coupling 69 is formed in an annular shape. The coupling 69 is spline-connected to both the electric motor 64 and the hydraulic pump 65.

[0030] The hydraulic pump 65 is disposed on a side end (the right end in this embodiment) of the revolving frame 31 and behind the electric motor 64 .

[0031] The hydraulic pump 65 has a rotary shaft 65a arranged along the front-rear direction. The axis of the rotary shaft 65a of the hydraulic pump 65 substantially coincides with the axis of the drive shaft 64a of the electric motor 64. The rotary shaft 65a of the hydraulic pump 65 is coupled to the drive shaft 64a of the electric motor 64 on the inner side of a coupling 69. Note that the rotary shaft 65a of the hydraulic pump 65 may be coupled to the drive shaft 64a of the electric motor 64 via an intermediate member.

[0032] The hydraulic pump 65 is connected to a hydraulic oil tank 66 by a suction pipe 70. The suction pipe 70 is a pipe that guides hydraulic oil from the hydraulic oil tank 66 to the hydraulic pump 65. The hydraulic pump 65 is connected to a hydraulic valve 67 by a supply pipe 71. The supply pipe 71 is a pipe that guides hydraulic oil from the hydraulic pump 65 to the hydraulic valve 67. In this embodiment, two supply pipes 71 are used, but the number of supply pipes 71 can be changed as appropriate.

[0033] When the rotation shaft 65a of the hydraulic pump 65 rotates in accordance with the rotation of the drive shaft 64a of the electric motor 64, the hydraulic pump 65 sucks hydraulic oil from the suction pipe 70 and discharges the hydraulic oil to the supply pipe 71. In this way, hydraulic oil is supplied from the hydraulic oil tank 66 to the hydraulic valve 67.

[0034] The hydraulic oil tank 66 is disposed on a side end (the right end in this embodiment) of the revolving frame 31, in front of the electric motor 64. The hydraulic oil tank 66 is a box-shaped container. The hydraulic oil tank 66 stores hydraulic oil therein.

[0035] The hydraulic oil tank 66 supplies hydraulic oil to the hydraulic pump 65 via a suction pipe 70. The front end of the suction pipe 70 is connected to the lower end of the hydraulic oil tank 66. The hydraulic oil stored in the hydraulic oil tank 66 is sucked into the hydraulic pump 65 through the suction pipe 70.

[0036] The hydraulic valve 67 is disposed on a side end (the right end in this embodiment) of the revolving frame 31, in front of the hydraulic oil tank 66. Hydraulic oil discharged from the hydraulic pump 65 is supplied to the hydraulic valve 67 via a supply pipe 71. The hydraulic valve 67 supplies hydraulic oil to the work implement drive section 41 of the work implement unit 4. This drives the work implement 40 of the work implement unit 4.

[0037] The high-voltage cable 68 is connected to the inverter 63 and the electric motor 64. The high-voltage cable 68 supplies the electric power supplied from the battery device 61 via the inverter 63 to the electric motor 64.

[0038] As shown in Figure 4, the high-voltage cable 68 extends from the electric motor 64 toward the center in the vehicle width direction. In this embodiment, the electric motor 64 is disposed on the right end of the revolving frame 31, and therefore the high-voltage cable 68 extends leftward from the electric motor 64 toward the inverter 63. In Figure 4, the center in the vehicle width direction is indicated by a line Lb that passes through the center of the revolving frame 31 in the vehicle width direction.

[0039] As shown in Figure 4, the high-voltage cable 68 is disposed closer to the center in the vehicle width direction than the outer edge of the electric motor 64 in the vehicle width direction in top view. In this embodiment, the electric motor 64 is disposed on the right end of the revolving frame 31, and therefore the high-voltage cable 68 is disposed closer to the center in the vehicle width direction than the right outer edge of the electric motor 64. The outer edge of the electric motor 64 in the vehicle width direction is the area of ​​the electric motor 64 that faces the body cover 32 (not shown in Figure 4, see Figure 1) in top view. In Figure 4, the right outer edge of the electric motor 64 is indicated by line Lc.

[0040] The suction pipe 70 is connected to the hydraulic pump 65 and the hydraulic oil tank 66. As shown in Fig. 4, the suction pipe 70 extends along the drive shaft 64a of the electric motor 64. In this embodiment, since the drive shaft 64a of the electric motor 64 extends in the front-rear direction, the suction pipe 70 also extends in the front-rear direction.

[0041] 4, the suction pipe 70 overlaps with the electric motor 64 in a top view. The suction pipe 70 passes inside the electric motor 64 in a top view. The suction pipe 70 does not protrude to the left or right of the electric motor 64. In this embodiment, the suction pipe 70 is disposed below the electric motor 64. Therefore, the suction pipe 70 extends in the front-rear direction between the electric motor 64 and the revolving frame 31.

[0042] As shown in Figure 4, the suction pipe 70 is composed of a horizontal pipe 70a and a vertical pipe 70b. The horizontal pipe 70a extends horizontally (in the front-to-rear direction in this embodiment) below the electric motor 64 and the hydraulic pump 65. The vertical pipe 70b extends vertically below the hydraulic pump 65. The front end of the horizontal pipe 70a is connected to the lower end of the hydraulic oil tank 66. The rear end of the horizontal pipe 70a is connected to the lower end of the vertical pipe 70b. The upper end of the vertical pipe 70b is connected to the lower surface of the hydraulic pump 65.

[0043] (Features) (1) In the electric excavator 1, the suction pipe 70 overlaps with the electric motor 64 in a top view. This reduces the space required in the vehicle width direction to accommodate the electric motor 64 and the suction pipe 70 compared to when the suction pipe 70 does not overlap with the electric motor 64. This allows the hydraulic pump 65 and the electric motor 64 to be appropriately positioned in a limited space.

[0044] (2) In the electric shovel 1, the suction pipe 70 is disposed below the electric motor 64. This makes it easy to connect the front end of the suction pipe 70 to the lower end of the hydraulic oil tank 66. Therefore, hydraulic oil that does not contain air bubbles can be taken into the suction pipe 70 from the hydraulic oil tank 66.

[0045] (Modifications of the Embodiment) Although the embodiment of the present invention has been described above, the present invention is not limited to this and can be modified as appropriate within the scope of the technical idea of ​​the invention.

[0046] (Variation 1) In the above embodiment, the hydraulic pump 65, the electric motor 64, and the hydraulic oil tank 66 are arranged on the right end of the revolving frame 31, but they may also be arranged on the left end of the revolving frame 31. In this case, the cab 5 is arranged on the right end of the revolving frame 31.

[0047] (Variant 2) In the above embodiment, the front end of the electric motor 64 is located rearward of the rotation center Ax of the upper rotating body 3, but it may also overlap with the rotation center Ax or be located forward of the rotation center Ax.

[0048] (Modification 3) In the above embodiment, the hydraulic valve 67 is arranged in front of the hydraulic oil tank 66, but this is not limitative. The position of the hydraulic valve 67 can be changed as appropriate.

[0049] (Modification 4) In the above embodiment, the high-voltage cable 68 extends from the electric motor 64 toward the center in the vehicle width direction, but this is not limited to this. For example, the high-voltage cable 68 may extend from the electric motor 64 toward the front or rear.

[0050] (Variation 5) In the above embodiment, the high-voltage cable 68 is arranged closer to the center in the vehicle width direction than the outer edge of the electric motor 64 in the vehicle width direction when viewed from above, but this is not limited to this. For example, only a portion of the high-voltage cable 68 may be arranged outside the outer edge of the electric motor 64 in the vehicle width direction.

[0051] (Modification 6) In the above embodiment, the hydraulic pump 65, the electric motor 64, and the hydraulic oil tank 66 are arranged in this order from rear to front, but they may also be arranged in this order from front to back.

[0052] (Seventh Modification) In the above embodiment, the suction pipe 70 is arranged below the electric motor 64 , but it may be arranged above the electric motor 64 .

[0053] (Variation 8) In the above embodiment, an electric shovel has been described as an example of an electric work machine, but the electric work machine is not limited to this. The electric work machine may be any machine that operates the work equipment using power from a battery device, and examples of such electric work machines include an electric wheel loader and a motor grader.

[0054] 1...electric excavator, 2...undercarriage, 3...upper rotating body, 31...swivel frame, 32...body cover, 4...working machine unit, 5...cab, 61...battery device, 62...BTMS, 63...inverter, 64...electric motor, 65...hydraulic pump, 66...hydraulic oil tank, 67...hydraulic valve, 68...high voltage cable, 69...coupling, 70...suction pipe, 80...distribution board

Claims

1. An electric working machine comprising: a hydraulic pump that discharges hydraulic oil; an electric motor that drives the hydraulic pump; a hydraulic oil tank that supplies hydraulic oil to the hydraulic pump; and a suction pipe that is connected to the hydraulic pump and the hydraulic oil tank and extends along an output shaft of the electric motor, wherein the suction pipe overlaps with the electric motor in a top view.

2. The electric working machine according to claim 1, wherein the suction pipe is disposed below the electric motor.

3. The electric working machine according to claim 1 or 2, wherein the hydraulic oil tank is disposed in front of the electric motor.

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