Carrier

Abstract

To provide a crawler mechanism capable of more efficiently transmitting driving force on a pivot to a front chassis and a rear chassis.SOLUTION: A transport vehicle 11 comprises: one vehicle body; right and left front crawlers 13; a front chassis 15 which supports the front crawler 13 and couples the front crawler 13 to the vehicle body pivotally on a first pivotal axis 16; right and left rear crawlers 14 which are arranged behind the front crawler 13; a rear chassis 17 which supports the rear crawler 14, and couples the rear crawler 14 to the vehicle body pivotally on a second pivotal axis 18 arranged behind the first pivotal axis 16 at an interval; and a steering mechanism 81 which couples the rear chassis 17 to the front chassis 15 and drives the rear chassis 17 on the second pivotal axis 18 reversely to the front chassis 15 as the front chassis 15 swivels.SELECTED DRAWING: Figure 8

Description

Technical Field

[0001] The present invention relates to a carrier vehicle including a body, left and right front crawlers, a front chassis that supports the front crawlers and connects the crawlers to the body so as to be rotatable about a swivel axis, and left and right rear crawlers disposed behind the front crawlers.

Background Art

[0002] Patent Document 1 discloses a crawler-type construction machine including left and right front crawlers and left and right rear crawlers disposed behind the front crawlers. In the body of this crawler-type construction machine, a front chassis (front frame) and a rear chassis (rear frame) are connected to each other so as to be bendable in a horizontal plane. In swivel traveling, the front chassis is steered in the left-right direction with respect to the rear chassis. In steering, expandable and contractible actuators such as hydraulic cylinders are connected to the front chassis and the rear chassis. [[ID=|13]]

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] In Patent Document 1, among the driving forces exerted by the actuators, the tangential component (tangential component of the driving force) around the swivel axis significantly contributes to the bending of the front chassis and the rear chassis. However, since the front chassis and the rear chassis are directly connected by a single rotation axis, at the acting points of the forces established by the front chassis and the rear chassis, the hydraulic cylinders must intersect at a large crossing angle with respect to the tangential direction. Thus, as the crossing angle increases, the tangential component of the driving force acting on the front chassis or the rear chassis from the hydraulic cylinders decreases.

[0005] An object of the present invention is to provide a crawler mechanism that can more efficiently transmit a driving force around a turning axis to a front vehicle body or a rear vehicle body. **Means for Solving the Problem**

[0006] According to a first aspect of the present invention, there is provided a transport vehicle including: one vehicle body; left and right front crawlers; a front vehicle body that supports the front crawlers and connects the front crawlers to the vehicle body rotatably about a first turning axis; left and right rear crawlers disposed behind the front crawlers; a rear vehicle body that supports the rear crawlers and connects the rear crawlers to the vehicle body rotatably about a second turning axis disposed at a distance rearward from the first turning axis; and a steering mechanism that connects the front vehicle body to the rear vehicle body and drives the rear vehicle body about the second turning axis in a direction opposite to the rotation of the front vehicle body in response to the turning of the front vehicle body.

[0007] During turning travel, the front vehicle body turns about a first turning axis in front of the vehicle body. The rear vehicle body turns about a second turning axis behind the vehicle body. Thus, since the turning axes are separated between the front vehicle body and the rear vehicle body, the crossing angle between the tangential direction around the turning axis and the acting direction of the driving force can be reduced at the acting points of the forces established by the front vehicle body and the rear vehicle body. The tangential direction component of the driving force increases in the front vehicle body and the rear vehicle body. The driving force can be efficiently transmitted to the front vehicle body and the rear vehicle body.

[0008] A larger ground contact area may be set for the rear crawlers than for the front crawlers. Since the resistance to turning is set smaller for the front crawlers than for the rear crawlers, good steering performance can be ensured.

[0009] The front chassis may be connected to the vehicle body so as to be tiltable in the left-right direction, and the rear chassis may be connected to the vehicle body so as to be tiltable in the left-right direction. When the vehicle body is maintained in a specific position in the left-right direction, the front crawlers and the rear crawlers can be supported on the ground with as large a contact area as possible by following the slope in the left-right direction. As a result, propulsive force can be efficiently transmitted from the front crawlers and the rear crawlers to the ground.

[0010] According to a second aspect of the present invention, there is provided a transport vehicle comprising a vehicle body, left and right front crawlers, a front chassis that supports the front crawlers and is connected to the vehicle body so as to be tiltable in the left and right directions, left and right rear crawlers that are arranged behind the front crawlers, and a rear chassis that supports the rear crawlers and is connected to the vehicle body so as to be tiltable in the left and right directions.

[0011] When the vehicle body is maintained in a specific position in the left-right direction, the front and rear crawlers can be supported on the ground with as large a contact area as possible by following the slope in the left-right direction, thereby efficiently transmitting propulsive force from the front and rear crawlers to the ground. [Effects of the Invention]

[0012] As described above, the transporter disclosed herein can provide a crawler mechanism that can transmit driving force around the turning axis to the front chassis and rear chassis more efficiently. [Brief explanation of the drawings]

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

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Figure 8

Figure 9

Figure 10

Embodiments for Carrying out the Invention

[0014] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0015] FIG. 1 is a side view schematically showing the overall configuration of a transporter according to an embodiment of the present invention. The transporter 11 includes a single vehicle body 12, left and right front crawlers 13 that support the vehicle body 12 on the ground GD, and left and right rear crawlers 14 that are arranged behind the front crawlers 13 and support the vehicle body 12 on the ground GD. The front crawlers 13 are supported by the front vehicle platform 15. The front vehicle platform 15 connects the front crawlers 13 to the vehicle body 12 so as to be rotatable around the first turning axis 16. The rear crawlers 14 are supported by the rear vehicle platform 17. The rear vehicle platform 17 connects the rear crawlers 14 to the vehicle body 12 so as to be rotatable around the second turning axis 18. The second turning axis 18 is arranged parallel to the first turning axis 16 at a position behind the first turning axis 16. When the first turning axis 16 and the second turning axis 18 are arranged in the vertical direction (gravity direction), the horizontal posture of the vehicle body 12 is established.

[0016] As shown in FIG. 2, the vehicle body 12 includes a main body frame 21 that is rotatably connected to the front vehicle platform 15 around the first turning axis 16 and is rotatably connected to the rear vehicle platform 17 around the second turning axis 18, and a work floor 23 that has a front end rotatably connected around a coupling shaft 22 at the front end of the main body frame 21 and changes its posture with respect to the main body frame 21 around the coupling shaft 22. The work floor 23 can be maintained in a horizontal posture regardless of the inclination of the ground GD according to the movement around the coupling shaft 22.

[0017] An engine 24, which is a power source, is mounted on the work floor 23. The engine 24 generates power by burning fuel supplied from a fuel tank 25. The fuel can be gasoline, diesel, alcohol, hydrogen, or other fuel. The structure of the engine 24 is determined depending on the type of fuel. The power can be extracted, for example, as rotational force of a drive shaft. The fuel tank 25 is attached to the work floor 23, for example.

[0018] A hydraulic pump 26 is connected to the engine 24. The hydraulic pump 26 is capable of generating hydraulic pressure based on the power supplied from the engine 24. To generate hydraulic pressure, hydraulic oil is supplied to the hydraulic pump 26 from a hydraulic oil tank 27. The hydraulic oil tank 27 is attached to the work floor 23, for example.

[0019] An operating device 28 is installed on the work platform 23. The operating device 28 is connected to the hydraulic pump 26 and hydraulic oil tank 27, and includes a control valve 29 that controls the hydraulic pressure supplied to the hydraulic motors and hydraulic cylinders described below. The hydraulic pressure of the hydraulic pump 26 is distributed to each hydraulic cylinder and hydraulic motor by the action of the control valve 29. The hydraulic cylinders and hydraulic motors operate in accordance with the distribution of the hydraulic pressure. The operating device 28 is connected to the control valve 29 and can include an operating lever 31 that is operated to distribute the hydraulic pressure. The operation of the hydraulic cylinders and hydraulic motors can be controlled in accordance with the operation of the operating lever 31.

[0020] A lift mechanism 33 is connected to the work platform 23 and the main body frame 21. The lift mechanism 33 is connected to the main body frame 21 by a first connecting shaft 34 and includes a first arm member 35 extending forward from the first connecting shaft 34, and a second arm member 38 connected to the front end of the first arm member 35 by a second connecting shaft 36 and extending rearward from the second connecting shaft 36, with a rear end connected to the work platform 23 by a third connecting shaft 37. The first connecting shaft 34 is disposed rearward and spaced apart from the connecting shaft 22 and parallel to it. The second connecting shaft 36 is disposed forward and spaced apart from the first connecting shaft 34 and parallel to it. The third connecting shaft 37 is disposed rearward and spaced apart from the second connecting shaft 36 and parallel to it.

[0021] The lift mechanism 33 includes a first hydraulic cylinder 39 connected to the main body frame 21 and a second arm member 38. One end of the first hydraulic cylinder 39 is connected to the main body frame 21 so as to be rotatable about a rotation axis 41 parallel to the connecting shaft 22. The other end of the first hydraulic cylinder 39 is connected to the second arm member 38 between the second connecting shaft 36 and the third connecting shaft 37 so as to be rotatable about a rotation axis 42 parallel to the connecting shaft 22. The inclination angle α between the main body frame 21 and the work platform 23 can be adjusted by extending and retracting the first hydraulic cylinder 39. By adjusting the inclination angle α in this way, the horizontal position of the work platform 23 can be established regardless of the fore-and-aft inclination of the ground GD.

[0022] A winch 43 is installed on the main body frame 21. A first hydraulic motor 44, which is driven in response to hydraulic pressure supplied from the hydraulic pump 26, is connected to the winch 43. The winch 43 can wind up the wire Wr based on the power supplied from the first hydraulic motor 44. The winch 43 has a drum that rotates, for example, around an axis parallel to the connecting shaft 22 and holds the wire Wr.

[0023] 3, the front chassis 15 is provided with a rotating body 45 that is disposed below the work platform 23 and is connected to the main frame 21 so as to be rotatable about a first rotation axis 16, and a support body 47 that is disposed below the rotating body 45 and is connected to the rotating body 45 so as to be rotatable about a first fulcrum axis 46 that is perpendicular to the first rotation axis 16. A tilt adjustment mechanism 48 is connected to the rotating body 45 and the support body 47.

[0024] The tilt adjustment mechanism 48 includes a swinging body 49 fixed to the support 47 and extending away from the first fulcrum axis 46, and a second hydraulic cylinder 51 connected to the swinging body 49 and the rotating body 45. One end of the second hydraulic cylinder 51 is connected to the swinging body 49 at a position away from the first fulcrum axis 46 so as to be rotatable about a rotation axis 52 parallel to the first fulcrum axis 46. The other end of the second hydraulic cylinder 51 is connected to the rotating body 45 so as to be rotatable about a rotation axis 53 parallel to the first fulcrum axis 46. As shown in FIG. 4 , the tilt angle β between the rotating body 45 and the support 47 about the first fulcrum axis 46 can be adjusted by extending or retracting the second hydraulic cylinder 51. By adjusting the tilt angle β, the horizontal position of the work platform 23 can be maintained regardless of the lateral tilt of the ground GD.

[0025] On the support body 47, the left and right front crawlers 13 are individually connected so as to be rotatable around a second fulcrum axis 55 extending in the left - right direction of the vehicle body 12. As shown in FIG. 5, the front crawler 13 includes a second hydraulic motor 56, a drive wheel 58 connected to the second hydraulic motor 56 and rotating around a rotation axis 57 according to the driving force of the second hydraulic motor 56, a roller 61 disposed in front of the drive wheel 58 and rotating around a rotation axis 59 parallel to the rotation axis 57 of the drive wheel 58, and a crawler (shoe) 62 wound around the drive wheel 58 and the roller 61, received by the ground GD between the drive wheel 58 and the roller 61, and transmitting the driving force of the drive wheel 58 to the ground GD. As shown in FIG. 6, the front crawler 13 can rotate around the second fulcrum axis 55 and follow the unevenness of the ground GD. The second hydraulic motor 56 is incorporated into each front crawler 13 for each individual front crawler 13. Since each individual front crawler 13 may have a structure similar to that of an existing crawler, the detailed description of the front crawler 13 is omitted here.

[0026] As shown in FIG. 7, the rear chassis 17, similar to the front chassis 15, is disposed below the work floor 23 and includes a swivel body 64 rotatably connected to the main body frame 21 around a second swivel axis 18, and a support body 66 disposed below the swivel body 64 and rotatably connected to the swivel body 64 around a third fulcrum axis 65 orthogonal to the second swivel axis 18. An inclination adjustment mechanism 67 is connected to the swivel body 64 and the support body 66.

[0027] The inclination adjustment mechanism 67 is fixed to the support 66 and includes a swing body 68 that extends away from the third fulcrum axis 65, and a third hydraulic cylinder 69 that is connected to the swing body 68 and the swivel body 64. One end of the third hydraulic cylinder 69 is connected to the swing body 68 rotatably about a rotation axis 71 parallel to the third fulcrum axis 65 at a position away from the third fulcrum axis 65. The other end of the third hydraulic cylinder 69 is connected to the swivel body 64 rotatably about a rotation axis 72 parallel to the third fulcrum axis 65. According to the expansion and contraction of the third hydraulic cylinder 69, the inclination angle between the swivel body 64 and the support 66 about the third fulcrum axis 65 can be adjusted. According to such adjustment of the inclination angle, the horizontal posture of the work floor 23 can be established regardless of the left-right inclination of the ground GD.

[0028] The left and right rear crawlers 14 are individually connected to the support 66 rotatably about a fourth fulcrum axis 73 extending in the left-right direction of the vehicle body 12. The rear crawler 14 includes a third hydraulic motor 74, a drive wheel 76 that is connected to the third hydraulic motor 74 and rotates about a rotation axis 75 according to the driving force of the third hydraulic motor 74, a roller 78 that is disposed in front of the drive wheel 76 and rotates about a rotation axis 77 parallel to the rotation axis 75 of the drive wheel 76, and a crawler (shoe) 79 that is wound around the drive wheel 76 and the roller 78 and receives the driving force of the drive wheel 76 between the drive wheel 76 and the roller 78 and transmits it to the ground GD. As shown in FIG. 6, the rear crawler 14 can rotate about the fourth fulcrum axis 73 and follow the unevenness of the ground GD. The third hydraulic motor 74 is incorporated into each individual rear crawler 14 for each rear crawler 14. Since each individual rear crawler 14 may have the same structure as an existing crawler, the detailed description of the rear crawler 14 is omitted here.

[0029] In the rear crawler 14, the distance between the rotation axis 75 of the drive wheel 76 and the rotation axis 77 of the roller 78 is set to be larger than the distance between the drive wheel 58 and the roller 61 of the front crawler 13. Therefore, a larger ground contact area is set for the rear crawler 14 than for the front crawler 13. When increasing the ground contact area, the width of the crawler 79 can be set larger for the rear crawler 14 than for the front crawler 13.

[0030] As shown in FIG. 8, a steering mechanism 81 is connected to the swivel body 45 of the front chassis 15 and the swivel body 64 of the rear chassis 17. The steering mechanism 81 includes a connecting member 82 that connects the swivel body 64 of the rear chassis 17 to the swivel body 45 of the front chassis 15, and a fourth hydraulic cylinder 83 that is connected to the swivel body 45 of the front chassis 15 and the connecting member 82. One end of the connecting member 82 is rotatably connected to the swivel body 45 of the front chassis 15 around a rotation axis 84 parallel to the first swivel axis 16. The other end of the connecting member 82 is rotatably connected to the swivel body 64 of the rear chassis 17 around a rotation axis 85 parallel to the second swivel axis 18. The connecting member 82 intersects a virtual plane Vp including the first swivel axis 16 and the second swivel axis 18. Therefore, the rear chassis 17 is driven counterclockwise with respect to the front chassis 15 in response to the turning of the front chassis 15. When the front chassis 15 turns clockwise around the first swivel axis 16, the connecting member 82 causes the rear chassis 17 to turn counterclockwise around the second swivel axis 18. When the front chassis 15 turns counterclockwise around the first swivel axis 16, the connecting member 82 causes the rear chassis 17 to turn clockwise around the second swivel axis 18.

[0031] One end of the fourth hydraulic cylinder 83 is rotatably connected to the swivel body 45 of the front chassis 15 around a rotation axis 86 parallel to the first swivel axis 16. The other end of the fourth hydraulic cylinder 83 is rotatably connected to the connecting member 82 around a rotation axis 87 parallel to the first swivel axis 16. The inclination angle γ between the connecting member 82 and the swivel body 45 changes according to the expansion and contraction of the fourth hydraulic cylinder 83. As shown in FIG. 9, the turning of the front crawler 13 and the turning of the rear crawler 14 are caused in response to such a change in the inclination angle γ. The turning of the front crawler 13 and the turning of the rear crawler 14 are interlocked.

[0032] As shown in FIG. 10 , a control device 91 that controls the operation of the control valve 29 is connected to the control valve 29. An operating lever 31 is connected to the control device 91. The rotation and steering of the front crawler 13 and rear crawler 14, and the rotation of the winch 43 can be controlled according to the operation of the operating lever 31. The traveling speed and traveling direction can be determined based on the rotation and steering of the front crawler 13 and rear crawler 14. The rotation of the winch 43 can be switched between an independent mode in which it is controlled independently from the operation of the front crawler 13 and rear crawler 14, and an interlocking mode in which it is interlocked with the operation of the front crawler 13 and rear crawler 14. In the interlocking mode, for example, the winding length of the wire Wr is adjusted to match the traveling distance. The interlocking mode can be used, for example, when going up and down slopes.

[0033] A level sensor 92 that detects the horizontal level of the work platform 23 in the left-right direction is connected to the control device 91, for example. The control device 91 can control the operation of the inclination adjustment mechanisms 48, 67 in accordance with the output of the level sensor 92. In this way, the horizontal position of the work platform 23 in the left-right direction can be maintained. The control device 91 may calculate the horizontal level of the work platform 23 in the front-to-rear direction based on the output of the level sensor 92. The control device 91 can control the operation of the lift mechanism 33 based on the calculated horizontal level. In this way, the horizontal position of the work platform 23 in the front-to-rear direction can be ensured. In addition, the control device 91 can control the operation of the lift mechanism 33 in accordance with the operation of the operating lever 31. In this way, the worker can set the work platform 23 to any inclination angle α by operating the operating lever 31.

[0034] Next, the operation of the carrier 11 according to this embodiment will be described. When hydraulic pressure is supplied to the second hydraulic motor 56 and the third hydraulic motor 74 in response to the operation of the operation lever 31, the front crawler 13 and the rear crawler 14 rotate. The carrier 11 travels. During turning, hydraulic pressure is supplied to the fourth hydraulic cylinder 83 in response to the steering of the operation lever 31. As shown in FIG. 9, the inclination angle γ between the connecting member 82 and the swivel body 45 changes. In response to the change in the inclination angle γ, turning of the front crawler 13 and the rear crawler 14 is caused. So-called articulated steering is realized. Since the front crawler 13 and the rear crawler 14 travel in the direction of the traveling path respectively, the front crawler 13 and the rear crawler 14 can efficiently transmit the propulsive force to the ground GD without skidding. Since skidding is not required, good turning travel can be realized even on a hard and uneven ground GD.

[0035] At this time, the front chassis 15 turns around the first turning axis 16 in the front with respect to the vehicle body 12. The rear chassis 17 turns around the second turning axis 18 in the rear with respect to the vehicle body 12. Thus, since the turning axes are separated by the front chassis 15 and the rear chassis 17, the crossing angle θ can be reduced between the tangential direction around the turning axes 16, 18 and the acting direction of the driving force at the acting points of the forces established by the front chassis 15 and the rear chassis 17. The tangential direction component of the driving force increases at the front chassis 15 and the rear chassis 17. The driving force can be efficiently transmitted from the steering mechanism 81 to the front chassis 15 and the rear chassis 17.

[0036] In particular, in this embodiment, a larger ground contact area is set for the rear crawler 14 than for the front crawler 13. The resistance to turning is set smaller for the front crawler 13 than for the rear crawler 14. Therefore, good steerability can be ensured.

[0037] During high-altitude work, as shown in FIG. 2, the carrier 11 travels on a mountainside or other slope. For example, when hydraulic pressure is supplied to the first hydraulic cylinder 39 in response to the operation of the operation lever 31, the work floor 23 can be positioned at a specified inclination angle α. The horizontal posture of the work floor 23 can be ensured in the front-rear direction in response to the adjustment of the inclination angle α.

[0038] When hydraulic pressure is supplied to the second hydraulic cylinder 51, the tilt angle β between the rotating body 45 and the support body 47 can be adjusted in the left-right direction. In the front chassis 15, the horizontal position of the working platform 23 can be ensured in the left-right direction in accordance with the adjustment of the tilt angle β. Similarly, when hydraulic pressure is supplied to the third hydraulic cylinder 69, the tilt angle between the rotating body 64 and the support body 66 can be adjusted in the left-right direction. In the rear chassis 17, the horizontal position of the working platform 23 can be ensured in the left-right direction in accordance with the adjustment of the tilt angle.

[0039] In this embodiment, the front chassis 15 is connected to the main frame 21 of the vehicle body 12 so as to be tiltable in the left-right direction, and the rear chassis 17 is connected to the main frame 21 of the vehicle body 12 so as to be tiltable in the left-right direction. When the vehicle body 12 is maintained in a specific posture in the left-right direction, the front crawlers 13 and the rear crawlers 14 can be received on the ground GD with as large a contact area as possible by following the slope in the left-right direction. As a result, propulsive force can be efficiently transmitted from the front crawlers 13 and the rear crawlers 14 to the ground GD. Here, it is conceivable to set a height difference between the left and right crawlers so that they follow the slope in the left-right direction when maintaining the posture in the left-right direction. In this case, although the horizontal posture of the work platform can be maintained in the left-right direction, for example, depending on the height difference between the left and right, the contact area of the crawlers with the ground GD will be reduced. [Explanation of symbols]

[0040] 11...transport vehicle, 12...vehicle body, 13...front crawler, 14...rear crawler, 15...front chassis, 16...first turning axis, 17...rear chassis, 18...second turning axis, 81...steering mechanism.

Claims

1. One vehicle body, Left and right front crawlers, A front chassis that supports the left and right front crawlers and connects the left and right front crawlers to the vehicle body so as to be rotatable about a common first rotation axis, Left and right rear crawlers arranged behind the left and right front crawlers, A rear chassis that supports the left and right rear crawlers and connects the left and right rear crawlers to the vehicle body so as to be rotatable about a common second rotation axis arranged at a distance rearward from the first rotation axis, A steering mechanism that connects the front chassis to the rear chassis with a connecting member that intersects a virtual plane including the first rotation axis and the second rotation axis, and drives the rear chassis about the second rotation axis in the counterclockwise direction of the front chassis in response to the rotation of the front chassis A transport vehicle characterized by comprising.

2. The transport vehicle according to claim 1, further comprising a hydraulic cylinder connected to the connecting member and causing displacement of the connecting member with respect to the virtual plane according to expansion and contraction.

3. The transport vehicle according to claim 2, wherein a larger ground contact area is set for the rear crawler than for the front crawler.

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