Work machine

Abstract

To provide a work machine equipped with a power supply device capable of reducing the load on a power supply cable.SOLUTION: A work machine includes a vehicle body and a power supply device that obtains power to operate the vehicle body through a power supply cable. The power supply device includes a base supported on the vehicle body, a housing supported on the base so as to be rotatable about a rotation axis extending in a first direction, a slip ring housed in the housing, and a cable protection bracket that protects the power supply cable connected to the slip ring. The cable protection bracket includes a bracket that supports the power supply cable, and a hinge that supports the bracket relative to the housing so as to be rotatable about a pivot axis extending in a second direction perpendicular to the first direction. The hinge is positioned at a position that is off an imaginary line that passes through the rotation axis and is perpendicular to the pivot axis when the power supply device is viewed from the first direction.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to an electric work machine. [Background technology]

[0002] Electric hydraulic excavators that operate using power supplied via a power supply cable have been known (see, for example, Patent Document 1). The electric hydraulic excavator described in Patent Document 1 connects the power supply cable to a slip ring mounted on the vehicle body to prevent twisting of the power supply cable caused by movement of the vehicle body. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5937534 Summary of the Invention [Problem to be solved by the invention]

[0004] However, if an external force directed toward the center of rotation of the slip ring is applied to the power supply cable, the slip ring may not rotate and a large load may act on the power supply cable.

[0005] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a work machine equipped with a power supply device that can reduce the load on the power supply cable. [Means for solving the problem]

[0006] In order to achieve the above object, the present invention provides a work machine including a vehicle body and a power supply device that obtains power to operate the vehicle body through a power supply cable, wherein the power supply device includes a base supported on the vehicle body, a housing supported on the base so as to be rotatable about a rotation axis extending in a first direction, a slip ring housed in the housing, and a cable protection bracket that protects the power supply cable connected to the slip ring, wherein the cable protection bracket includes a bracket that supports the power supply cable, and a hinge that supports the bracket relative to the housing so as to be rotatable about a rotation axis that extends in a second direction perpendicular to the first direction, and the hinge is arranged at a position that is off an imaginary line that passes through the rotation axis and is perpendicular to the rotation axis when the power supply device is viewed from the first direction. [Effects of the Invention]

[0007] According to the present invention, it is possible to reduce the load on the power supply cable. Note that problems, configurations, and effects other than those described above will become apparent from the following description of the embodiments. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a side view of a hydraulic excavator. [Figure 2] FIG. [Figure 3] 3A and 3B are perspective views of the cable protection bracket when the bracket is in a first position (A) and a second position (B). [Figure 4] 3A and 3B are side views of the cable protection bracket when the bracket is in a first position (A) and a second position (B). [Figure 5] FIG. [Figure 6] 10A and 10B are diagrams illustrating how an external force applied to the power supply cable causes the bracket to rotate and the housing to turn. DETAILED DESCRIPTION OF THE INVENTION

[0009] [Configuration of Hydraulic Excavator 1] An embodiment of a hydraulic excavator 1 (work machine) according to the present invention will be described with reference to the drawings. The hydraulic excavator 1 according to this embodiment is an electrically powered work machine that operates using power supplied through a wired power supply cable 20. However, specific examples of the work machine are not limited to the hydraulic excavator 1, and may include a wheel loader, a dump truck, a crane truck, etc. Furthermore, unless otherwise specified, the terms front, back, left, and right in this specification are based on the viewpoint of an operator who is on board and operating the hydraulic excavator 1.

[0010] Fig. 1 is a side view of a hydraulic excavator 1. As shown in Fig. 1, the hydraulic excavator 1 includes a lower traveling body 2 and an upper rotating body 3 supported by the lower traveling body 2. The lower traveling body 2 and the upper rotating body 3 are an example of a vehicle body.

[0011] The lower traveling body 2 is equipped with a pair of left and right crawlers 4, which are endless tracks. The pair of left and right crawlers 4 are rotated independently by driving a traveling motor 5. As a result, the hydraulic excavator 1 travels. However, the lower traveling body 2 may be of a wheeled type instead of the crawlers 4.

[0012] The upper rotating body 3 is supported on the lower traveling body 2 so as to be rotatable by a swing motor 6. That is, when the swing motor 6 rotates, the upper rotating body 3 swings relative to the lower traveling body 2. The upper rotating body 3 mainly comprises a swing frame 7 serving as a base, a cab (operator's seat) 8 disposed on the front left side of the swing frame 7, a counterweight 9 disposed at the rear of the swing frame 7, a front work machine 10 (working device) attached to the front center of the swing frame 7 so as to be rotatable in the vertical direction, and a power supply device 30.

[0013] The cab 8 is disposed adjacent to the front working implement 10 in the left-right direction (the width direction of the vehicle body). More specifically, the cab 8 is disposed to the left (one side in the left-right direction) of the front working implement 10. However, the location of the cab 8 is not limited to the example described above, and the cab 8 may be disposed on one side of the front working implement 10 in the left-right direction.

[0014] The cab 8 is formed with a space for an operator to ride in and operate the hydraulic excavator 1. Inside the cab 8, a seat for the operator and an operating device to be operated by the operator seated in the seat are arranged. The operating device receives operations from the operator to operate the hydraulic excavator 1. When the operator operates the operating device, the lower traveling body 2 travels, the upper rotating body 3 rotates, and the front working implement 10 operates. Specific examples of the operating device include a lever, a steering wheel, a pedal, a switch, etc.

[0015] The front work implement 10 includes a boom 11 supported on the upper rotating body 3 so that it can be raised and lowered, an arm 12 supported at the tip of the boom 11 so that it can rotate (crowd, dump), a bucket 13 (attachment) supported at the tip of the arm 12 so that it can rotate (crowd, dump), a boom cylinder 14 that drives the boom 11, an arm cylinder 15 that drives the arm 12, and a bucket cylinder 16 that drives the bucket 13. Note that specific examples of the attachment are not limited to the bucket 13, and may include a grapple, cutter, crusher, breaker, etc. The counterweight 9 is a heavy object that has an arc shape when viewed from above and is used to balance the weight of the front work implement 10.

[0016] The power supply device 30 is a device that obtains power for operating the hydraulic excavator 1 from an external power source (not shown) via the power supply cable 20. More specifically, the power supply device 30 uses the power supplied from the power supply cable 20 to operate a motor (not shown), a controller (not shown), and other electrically powered devices (not shown) mounted on the hydraulic excavator 1.

[0017] The motor operates a hydraulic pump (not shown) that pumps hydraulic oil stored in a hydraulic oil tank (not shown). The hydraulic oil pumped from the hydraulic pump is then supplied to hydraulic actuators (for example, the travel motor 5, the swing motor 6, the boom cylinder 14, the arm cylinder 15, and the bucket cylinder 16), thereby operating the hydraulic excavator 1. The configuration of the hydraulic excavator 1 that operates using power output from an external power source is already well known, so a detailed description will be omitted.

[0018] The power feed cable 20 is a flexible (in other words, bendable) cable. The power feed cable 20 hangs down from, for example, the ceiling 21. As one example, the power feed cable 20 may be configured to be movable along a rail installed on the ceiling 21 as the hydraulic excavator 1 moves. As another example, the power feed cable 20 may be wound around a drum installed on the ceiling 21 and reeled out or wound up as the hydraulic excavator 1 moves. A specific configuration for hanging the power feed cable 20 down from the ceiling 21 is already well known, and therefore a detailed description thereof will be omitted. Furthermore, the power feed cable 20 may extend from a wall, a floor, or a housing of an external power source instead of the ceiling 21.

[0019] [Configuration of power supply device 30] Fig. 2 is a perspective view of the housing 32. Fig. 3 is a perspective view of the cable protection bracket 34 when the bracket 40 is in the first position (A) and the second position (B). Fig. 4 is a side view of the cable protection bracket 34 when the bracket 40 is in the first position (A) and the second position (B). Fig. 5 is a plan view of the power supply device 30. Fig. 6 is a diagram illustrating how the bracket 40 rotates and the housing 32 rotates due to an external force F applied to the power supply cable 20.

[0020] As shown in Fig. 1, the power supply device 30 is supported on the upper surface of the upper rotating body 3 (more specifically, rearward of the cab 8 and the front working implement 10). As shown in Figs. 1 to 5, the power supply device 30 mainly includes a base 31, a housing 32, a slip ring 33, and a cable protection bracket 34.

[0021] Hereinafter, the direction perpendicular to the mounting surface G of the hydraulic excavator 1 will be referred to as the "first direction," and the direction perpendicular to the first direction (i.e., the direction parallel to the mounting surface G) will be referred to as the "second direction." In other words, when the hydraulic excavator 1 is mounted on a horizontal surface, the first direction coincides with the up-down direction, and the second direction coincides with the horizontal direction. However, the absolute directions of the first direction and the second direction are not limited to the above-mentioned example, and may be any directions that are perpendicular to each other.

[0022] The pedestal 31 is fixed to the upper surface of the upper rotating body 3 (for example, the engine building or the counterweight 9). The pedestal 31 has a cylindrical outer shape extending upward from the upper rotating body 3. Inside the pedestal 31, a power line is routed that connects the slip ring 33 and the motor.

[0023] 2, the housing 32 is supported on the upper end of the base 31. The housing 32 is supported on the base 31 so as to be rotatable about a rotation axis X1, which is an imaginary line that passes through the center of the cylindrical base 31 and extends in a first direction. The housing 32 is box-shaped and has an internal space that houses the slip ring 33. The housing 32 has an outer surface that is provided with a support surface 35 and a connection surface 36.

[0024] The support surface 35 is a surface (more specifically, a plane) perpendicular to the first direction. The support surface 35 is also a surface facing upward. The support surface 35 is also a surface that supports the cable protection bracket 34. The connection surface 36 is a surface (more specifically, a plane) perpendicular to the second direction. The connection surface 36 is also a surface that protrudes upward from the outer edge of the support surface 35. That is, the support surface 35 and the connection surface 36 are surfaces that are perpendicular to each other. Furthermore, the connection surface 36 has a connection portion 37 formed thereon to which the tip of the power supply cable 20 is connected.

[0025] The connection portion 37 is a terminal that electrically connects the power feed cable 20 and the slip ring 33. When the tip of the power feed cable 20 is connected to the connection portion 37, power output from an external power source is supplied to the slip ring 33 through the power feed cable 20. In this embodiment, an example will be described in which the tip of the power feed cable 20 branches and is connected to four connection portions 37, but the number of connection portions 37 is not limited to this.

[0026] The slip ring 33 is an electrical component that transmits power between a stationary body and a rotating body. The slip ring is composed of, for example, a rotating body that is supported rotatably about a rotation axis X1, and a brush that slides against the rotating body. Electric power output from the power supply cable 20 connected to the connection part 37 is supplied to a motor or the like via the rotating body and the brush. The configuration of the slip ring 33 is already well known, so a detailed description thereof will be omitted.

[0027] The cable protection bracket 34 is a member that supports the power feed cable 20 (a portion near the tip connected to the connection portion 37) and protects that portion of the power feed cable 20. More specifically, the cable protection bracket 34 linearly supports a portion of the power feed cable 20. As shown in FIGS. 3 and 4 , the cable protection bracket 34 mainly includes, for example, a base plate 38, a hinge 39, a bracket 40, a fixing member 41, and a damper 42.

[0028] The base plate 38 is a flat plate-shaped member fixed onto the support surface 35. The base plate 38 also supports the hinge 39 and the damper 42. Note that the base plate 38 may be omitted, and the hinge 39 and the damper 42 may be fixed directly onto the support surface 35.

[0029] The hinge 39 is fixed onto the base plate 38 and supports the bracket 40 rotatably relative to the base plate 38. The hinge 39 is configured, for example, by a pair of plates that are rotatable relative to each other about a rotation axis X2, which is an imaginary line extending in the second direction. One of the pair of plates is fixed to the base plate 38, and the other is fixed to the lower end of the bracket 40. When the pair of plates open and close, the bracket 40 rotates about the rotation axis X2 relative to the base plate 38. The rotation axis X1 and the rotation axis X2 extend in directions perpendicular to each other.

[0030] The bracket 40 is supported by a support surface 35 (more specifically, a base plate 38) so as to be rotatable about a rotation axis X2 between a first position shown in FIGS. 3A and 4A and a second position shown in FIGS. 3B and 4B. The bracket 40 (more specifically, a main wall 40a, which will be described later) extends obliquely upward from the support surface 35 (more specifically, in a direction away from the connection surface 36). The bracket 40 also linearly supports a portion of the power supply cable 20. The bracket 40 is composed of, for example, the main wall 40a, a pair of side walls 40b and 40c, and a protective wall 40d.

[0031] The main wall 40a is a flat plate with a substantially rectangular shape having a short side direction and a long side direction. The pair of side walls 40b, 40c are flat plates fixed to both ends of the main wall 40a in the short side direction and extending in a direction perpendicular to the main wall 40a. The protective wall 40d is fixed to the pair of side walls 40b, 40c at a position spaced a predetermined distance from the main wall 40a. That is, a space into which the power supply cable 20 can enter is formed between the main wall 40a, the pair of side walls 40b, 40c, and the protective wall 40d.

[0032] The fixing member 41 is a member that fixes a portion of the power feed cable 20 to the main wall 40a. The fixing member 41 is composed of, for example, a plurality of U-bolts spaced apart in the extension direction of the power feed cable 20 and a thin plate with a U-shaped cross section that connects the plurality of U-bolts. The fixing member 41 is attached to the main wall 40a so as to cover the power feed cable 20 that extends along the main wall 40a. As a result, a portion of the power feed cable 20 is linearly supported by the main wall 40a.

[0033] 4(A), the first posture is a posture of the bracket 40 in which the angle θ1 formed between the part of the power supply cable 20 linearly supported by the bracket 40 (in other words, the main wall 40a) and the first direction is the largest. The first posture is also a posture of the bracket 40 in which the pair of plates constituting the hinge 39 abuts against each other (i.e., the hinge 39 is closed), and the weight of the bracket 40 is supported by the hinge 39.

[0034] 4(B), the second posture is a posture of the bracket 40 in which the angle θ2 formed between a part of the power supply cable 20 linearly supported by the bracket 40 (in other words, the main wall 40a) and the first direction is smaller than the angle θ1 in the first posture. The second posture is also a posture of the bracket 40 when a pair of plates constituting the hinge 39 are separated (i.e., the hinge 39 is open). The second posture is also a posture of the bracket 40 when the hinge 39 is fully opened.

[0035] That is, the bracket 40 in the first position is prevented from rotating away from the second position by the hinge 39. Furthermore, the bracket 40 in the second position is prevented from rotating away from the first position by the hinge 39. In other words, the hinge 39 allows the bracket 40 to rotate within the range between the first position and the second position, and prevents the bracket 40 from rotating beyond the range between the first position and the second position.

[0036] 5 and 6, when the bracket 40 in the first position is viewed from the first direction, the portion of the feed cable 20 supported by the bracket 40 extends in a direction perpendicular to the connection surface 36. On the other hand, when the bracket 40 in the second position is viewed from the first direction, as shown in the center diagram of FIG. 6, when the bracket 40 in the second position is viewed from the first direction, the portion of the feed cable 20 supported by the bracket 40 extends in a direction inclined (≠90°) with respect to the connection surface 36.

[0037] The damper 42 has one end rotatably connected to the bracket 40 (more specifically, the side wall 40b), and the other end rotatably connected to the support surface 35 (more specifically, the base plate 38). The rotation axes of both ends of the damper 42 extend in the second direction (i.e., parallel to the rotation axis X2). The damper 42 according to this embodiment is a coil spring type damper. The damper 42 generates resistance when the bracket 40 rotates from the first position to the second position. The damper 42 also biases the bracket 40 in the direction of rotation from the second position to the first position.

[0038] However, the specific configuration of the damper 42 is not limited to the above example, and may be gas-, air-, or oil-type. The damper 42 does not necessarily have the function of biasing the bracket 40 in the direction of rotation from the second position to the first position, and may instead generate resistance when the bracket 40 rotates from the second position to the first position. Furthermore, the damper 42 is not an essential component and may be omitted.

[0039] When no external force other than gravity is acting on the power feed cable 20 and no tension is applied to the power feed cable 20, the bracket 40 is maintained in the first position by its own weight and the biasing force of the damper 42. The own weight of the bracket 40 and the biasing force of the damper 42 are supported by the hinge 39. That is, the first position is the most stable position of the bracket 40.

[0040] On the other hand, when the hydraulic excavator 1 shown in FIG. 1 moves backward, tension is applied to the power feed cable 20, and an external force F is applied to the bracket 40. More specifically, as shown in the left diagram of FIG. 6, when the power feeding device 30 is viewed from the first direction, an external force F may be generated in a direction opposite to the extending direction of the power feed cable 20 and overlapping with the rotation axis X1. In this case, the external force F is resolved into a component force F1 parallel to the rotation axis X2 and a component force F2 perpendicular to the rotation axis X2. When the component force F2 becomes larger than the weight of the bracket 40 and the biasing force of the damper 42, the bracket 40 rotates from the first position to the second position.

[0041] 6, when the power supply device 30 is viewed from the first direction, the bracket 40, which is rotated from the first position to the second position by the component force F2, is inclined with respect to the direction of the external force F. When the bracket 40 reaches the second position, the hinge 39 prevents the bracket 40 from rotating.

[0042] Here, when viewing power supply device 30 from the first direction, the direction of component force F2 is deviated from rotation axis X1, and therefore component force F2 after bracket 40 reaches the second position acts as a moment load that rotates housing 32 relative to base 31. As a result, housing 32 rotates (clockwise in the case of FIG. 6) as shown in the right diagram of FIG. 6, and external force F acts in a direction that rotates bracket 40 from the second position to the first position. As a result, bracket 40 rotates again from the second position to the first position.

[0043] In order for the power supply device 30 to operate as described above, the extension direction of the rotation axis X2 when the power supply device 30 is viewed from the first direction (i.e., the second direction) should be inclined (≠90°) with respect to the line connecting the hinge 39 and the rotation axis X1 (i.e., the arrow indicating the external force F). In other words, as shown in Fig. 5, when the power supply device 30 is viewed from the first direction, the hinge 39 should be disposed at a position that is off an imaginary line L that passes through the rotation axis X1 and is perpendicular to the rotation axis X2.

[0044] [Effects of the embodiment] 6 , the extension direction of the rotation axis X2 when the power supply device 30 is viewed from the first direction is inclined with respect to the line connecting the hinge 39 and the rotation axis X1, so that the direction of the component force F2 of the external force F deviates from the rotation axis X1 when the power supply device 30 is viewed from the first direction. This causes the housing 32 to rotate in response to the external force F, thereby preventing a large load from acting on the power supply cable 20.

[0045] Furthermore, according to the above embodiment, the damper 42 generates resistance when the bracket 40 rotates from the first position to the second position, thereby preventing the bracket 40 from rotating suddenly. As a result, it is possible to prevent an impact load from being applied to the bracket 40 that is stopped in the second position. Similarly, if resistance is generated when the bracket 40 rotates from the first position to the second position, it is possible to prevent an impact load from being applied to the bracket 40 that is stopped in the first position.

[0046] Furthermore, according to the above embodiment, when the bracket 40 in the first position is viewed from the first direction as shown in Fig. 5 , the portion of the feed cable 20 supported by the bracket 40 is orthogonal to the connection surface 36, so that the tip of the feed cable 20 can be connected to the connection part 37 without being bent significantly. As a result, the load on the feed cable 20 is reduced.

[0047] The above-described embodiments are merely illustrative examples of the present invention, and are not intended to limit the scope of the present invention to these embodiments. Those skilled in the art can implement the present invention in various other forms without departing from the spirit of the present invention. [Explanation of symbols]

[0048] 1: Hydraulic excavator 2: Lower running body 3: Upper rotating body 4: Crawler 5:Traction motor 6: Swing motor 7: Swivel frame 8: Cab 9: Counterweight 10: Front work equipment 11: Boom 12: Arm 13: Bucket 14: Boom cylinder 15: Arm cylinder 16: Bucket cylinder 20: Power supply cable 21: Ceiling 30: Power supply device 31: Pedestal 32: Housing 33: Slip ring 34: Cable protection bracket 35: Support surface 36: Connection surface 37: Connection part 38: Base plate 39: Hinge 40: Bracket 40a: Main wall 40b,40c: Side wall 40d: Protective wall 41: Fixing member 42: Damper F: External force F1,F2: component force G: Placement surface X1: Rotation axis X2: Rotation axis

Claims

1. A work machine including a vehicle body and a power supply device that obtains power to operate the vehicle body through a power supply cable, The power supply device is a base supported by the vehicle body; a housing supported by the base so as to be rotatable about a rotation axis extending in a first direction; a slip ring housed in the housing; a cable protection bracket for protecting the power supply cable connected to the slip ring; The cable protection bracket is a bracket for supporting the power supply cable; a hinge that supports the bracket with respect to the housing so as to be rotatable about a rotation axis that extends in a second direction perpendicular to the first direction, a hinge disposed at a position deviated from an imaginary line that passes through the rotation axis and is perpendicular to the pivot axis when the power supply device is viewed from the first direction;

2. 2. The work machine according to claim 1, The bracket is a first position in which the weight of the bracket is supported by the hinge; a second orientation in which the angle between the power supply cable supported by the bracket and the first direction is smaller than the first orientation, When the power supply device is viewed from the first direction, of the external force applied to the bracket, a component of a force that rotates the bracket from the first posture to the second posture is in a direction that is deviated from the rotation axis.

3. 3. The work machine according to claim 2, The work machine, wherein the cable protection bracket further comprises a damper that generates resistance when the bracket rotates from the first position to the second position.

4. 3. The work machine according to claim 2, The housing includes: a support surface that is perpendicular to the first direction and supports the cable protection bracket; a connection surface that is perpendicular to the support surface and that is provided with a connection portion to which a tip of the power supply cable is connected.

5. 5. The work machine according to claim 4, a portion of the power supply cable supported by the bracket extending in a direction perpendicular to the connection surface when the bracket in the first position is viewed from the first direction.

Images