Working machinery

Abstract

To provide a work machine capable of improving the reliability of a steering operation device.SOLUTION: A steering operation device 42 includes a joystick 43, a first electric lever 60, and an input part 110. The joystick 43 receives the operation by the operator. The first electric lever 60 has a first body part 61, and a first lever part 62 capable of inclining to the first body part 61 for outputting the inclination angle of the first lever part 62 to the first body part 61. The input part 110 gives input to the first lever part 62 to incline the first lever part 62 of the first electric lever 60 to the first body part 61. The input part 110 has a long hole 111 extending in the longitudinal direction. The first lever part 62 is arranged in the long hole 111.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present disclosure relates to a working machine.

Background Art

[0002] Japanese Unexamined Patent Application Publication No. 2020-26230 (Patent Document 1) discloses a steering device for operating an articulated work vehicle. The joystick lever is configured to be rotatable with respect to a base member or a support portion. The lever angle sensor detects the angle of the joystick lever with respect to the support portion. The vehicle body frame angle sensor detects the rotation angle of the front frame with respect to the rear frame. The controller controls the electromagnetic pilot valve based on the detection value of the lever angle sensor and the detection value of the vehicle body frame angle sensor. The electromagnetic pilot valve adjusts the pilot hydraulic pressure supplied to the hydraulic valve. The hydraulic valve adjusts the flow rate of the oil supplied to the steering cylinder according to the input pilot hydraulic pressure.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Instead of a pilot valve that supplies pilot hydraulic pressure to a hydraulic valve, a steering operation device including an electric lever that detects the operation of a joystick is being devised. An electric signal corresponding to the operation of the joystick is output from the electric lever to the controller, and the controller controls the steering actuator according to the received electric signal.

[0005] In a steering operation device including an electric lever, it is desired to avoid a situation where no electric signal is output from the electric lever and improve reliability.

[0006] This disclosure proposes a work machine that can improve the reliability of the steering control device. [Means for solving the problem]

[0007] A work machine according to this disclosure comprises a body frame, a steering actuator, and a steering control device. The body frame has a rear frame and a front frame rotatably connected to the rear frame. The steering actuator changes the angle of the front frame relative to the rear frame. The steering control device is operated by an operator to operate the steering actuator. The steering control device includes a joystick, at least one electric lever, and an input unit. The joystick accepts input from the operator. The electric lever has a body and a lever portion that is tiltable relative to the body. The electric lever outputs the tilt angle of the lever portion relative to the body. The input unit inputs an input to the lever portion that tilts the lever portion relative to the body. The input unit has at least one elongated hole extending in a direction perpendicular to the direction in which the operator tilts the joystick. The lever portion is located within the elongated hole. [Effects of the Invention]

[0008] The working machine of this disclosure can improve the reliability of the steering control device. [Brief explanation of the drawing]

[0009] [Figure 1] This is a side view of a wheel loader as an example of a work machine based on an embodiment. [Figure 2] This is a perspective view showing the structure around the driver's seat inside the cab. [Figure 3] This is a schematic diagram of a wheel loader in a bent position, viewed from above. [Figure 4] This is a schematic diagram showing the linkage mechanism that transmits the current vehicle body bending angle to the steering control device. [Figure 5] This is a perspective view showing the configuration of the steering control system. [Figure 6] This is a perspective view of the joystick from a different angle. [Figure 7] This is a cross-sectional view of the steering control device. [Figure 8] This is a plan view of the steering control device. [Modes for carrying out the invention]

[0010] The embodiments will be described below with reference to the figures. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed descriptions of them will not be repeated.

[0011] <Overall configuration of wheel loader 1> In this embodiment, a wheel loader 1 will be described as an example of a work machine. Figure 1 is a side view of the wheel loader 1 as an example of a work machine based on this embodiment.

[0012] As shown in Figure 1, the wheel loader 1 comprises a body frame 2, a work implement 3, a running gear, a cab 5, and an engine hood 6. The body of the wheel loader 1 (the main body of the work implement) is composed of the body frame 2, cab 5, etc. The work implement 3 and running gear are attached to the body of the wheel loader 1.

[0013] The running gear is used to move the body of the wheel loader 1 and includes running wheels 4 and 7. The wheel loader 1 is a wheeled vehicle equipped with running wheels 4 and 7 as rotating bodies for travel on both sides of the body in the left-right direction. The wheel loader 1 is self-propelled by the rotational drive of the running wheels 4 and 7 and can perform desired operations such as excavation and loading of soil using the work implement 3.

[0014] In this specification, the direction in which the wheel loader 1 travels in a straight line is referred to as the longitudinal direction of the wheel loader 1. In the longitudinal direction of the wheel loader 1, the side on which the work equipment 3 is positioned relative to the vehicle frame 2 is defined as the forward direction, and the side opposite to the forward direction is defined as the rear direction. The left-right direction of the wheel loader 1 is the direction perpendicular to the longitudinal direction when the wheel loader 1 is viewed from above on a flat ground. Looking at the forward direction, the right and left sides of the left-right direction are the right direction and left direction, respectively. The up-down direction of the wheel loader 1 is the direction perpendicular to the plane defined by the longitudinal and left-right directions. In the up-down direction, the side with the ground is the down side, and the side with the sky is the up side.

[0015] In the drawings, the X direction, indicated by a double-headed arrow in Figure 1, represents the front-to-back direction. The XF direction is the forward direction, and the XR direction is the rear direction. In the drawings described later, the Y direction represents the left-to-right direction. The YL direction is the left direction, and the YR direction is the right direction.

[0016] The vehicle frame 2 includes a front frame 11 and a rear frame 12. The front frame 11 is positioned in front of the rear frame 12. The front frame 11 is connected to the rear frame 12 in a manner that allows for bending. The front frame 11 is rotatably connected to the rear frame 12 by a connecting shaft portion 13. The connecting shaft portion 13, which forms the pivot point of the front frame 11 relative to the rear frame 12, is an axis that extends in the vertical direction. The connecting shaft portion 13 is located in the center of the vehicle frame 2 in the left-right direction. The front frame 11 and the rear frame 12 constitute the articulated vehicle frame 2. The wheel loader 1 is an articulated type work machine in which the front frame 11 and the rear frame 12 are connected.

[0017] The front frame 11 and the rear frame 12 are connected by a steering actuator 21. The steering actuator 21 is disposed across the front frame 11 and the rear frame 12. The proximal end of the steering actuator 21 is attached to the rear frame 12. The distal end of the steering actuator 21 is attached to the front frame 11. The steering actuator 21 is provided in a pair on the left and right. The steering actuator 21 is arranged side by side on both sides in the left-right direction with the connecting shaft portion 13 interposed therebetween.

[0018] When the steering actuator 21 drives to expand and contract, the front frame 11 moves left and right with respect to the rear frame 12 about the connecting shaft portion 13. The steering actuator 21 is, for example, a hydraulic actuator. The steering actuator 21 is, for example, a hydraulic cylinder. The steering actuator 21 rotates the front frame 11 with respect to the rear frame 12. The expansion and contraction of the steering actuator 21 changes the bending angle of the front frame 11 with respect to the rear frame 12.

[0019] The front frame 11 is attached with a working machine 3 and a pair of left and right traveling wheels (front wheels) 4. The working machine 3 is disposed in front of the vehicle body and is supported by the vehicle body of the wheel loader 1. The working machine 3 includes a boom 14 and a bucket 15. The bucket 15 is disposed at the tip of the working machine 3. The bucket 15 is a working tool for excavation and loading.

[0020] The working machine 3 includes a boom cylinder 16. The front frame 11 and the boom 14 are connected by a pair of boom cylinders 16. The proximal end of the boom cylinder 16 is attached to the front frame 11. The distal end of the boom cylinder 16 is attached to the boom 14. The boom cylinder 16 is a hydraulic actuator that moves the boom 14 up and down with respect to the front frame 11. As the boom 14 moves up and down, the bucket 15 attached to the tip of the boom 14 also moves up and down.

[0021] The work machine 3 further includes a bell crank 18, a connecting link 19, and a bucket cylinder 17. The bell crank 18 is rotatably supported by the boom 14, approximately in the center of the boom 14. The bucket cylinder 17 connects the bell crank 18 to the front frame 11. The connecting link 19 is connected to the tip of the bell crank 18. The connecting link 19 connects the bell crank 18 to the bucket 15.

[0022] The base end of the bucket cylinder 17 is attached to the front frame 11. The tip of the bucket cylinder 17 is attached to the base end of the bell crank 18. The bucket cylinder 17 is a hydraulic actuator that moves the bucket 15 up and down relative to the boom 14. The bucket cylinder 17 is a work tool cylinder that drives the bucket 15. The bucket 15 is configured to be movable relative to the boom 14. The bucket 15 is configured to be movable relative to the front frame 11.

[0023] The rear frame 12 is fitted with an engine hood 6, a cab 5 where the operator sits, and a pair of running wheels (rear wheels) 7. The engine hood 6 is located behind the cab 5. Inside the engine hood 6 are the hydraulic oil tank, engine, hydraulic pump, and air cleaner.

[0024] The box-shaped cab 5 is located behind the work equipment 3. The cab 5 is mounted on the vehicle frame 2. The cab 5 is mounted on the rear frame 12. The cab 5 partitions the interior space where the operator sits. A door is provided on the left side of the cab 5, which is opened and closed when the operator enters or exits the cab 5.

[0025] Figure 2 is a perspective view showing the structure around the driver's seat 31 inside the cab 5. Inside the cab 5 are the driver's seat 31 where the operator sits, and operating devices operated by the operator to operate the wheel loader 1. The driver's seat 31 is located in the interior space partitioned by the cab 5. The operator operates the wheel loader 1 while seated in the driver's seat 31 inside the cab 5. As shown in Figure 2, the driver's seat 31 has a seat cushion 33, a seat back 32, a headrest 34, and a suspension mechanism 35.

[0026] The seat cushion 33 is installed horizontally. The seat cushion 33 is the seat portion on which the operator sits. The seat back 32 is installed so as to rise upward from the rear end of the seat cushion 33. The seat back 32 is the seat portion that serves as the operator's backrest. The headrest 34 is attached to the upper end of the seat back 32. The headrest 34 is the seat portion that supports the operator's head.

[0027] The suspension mechanism 35 is provided in the vertical direction between the floor surface of the cab 5 and the seat cushion 33. The suspension mechanism 35 elastically supports the seat cushion 33.

[0028] Inside the cab 5, a right armrest 36 and a right console 37 are located. The right armrest 36 and the right console 37 are located to the right of the driver's seat 31. The right console 37 is equipped with a work implement operating lever 38 and a dial device 39, among other things. The work implement operating lever 38 is operated to control the operation of the work implement 3. The dial device 39 is operated to control the movement of the wheel loader 1. The dial device 39 may also be a speed limit dial that is operated to specify the maximum speed at which the wheel loader 1 travels.

[0029] Inside cab 5, a left armrest 40 and a left console 41 are located. The left armrest 40 and left console 41 are located to the left of the driver's seat 31. The left console 41 is located between the driver's seat 31 and the door of cab 5 in the left-right direction. The right console 37 and left console 41 are located above the seat cushion 33. The right armrest 36 and left armrest 40 are located above the seat cushion 33. The right armrest 36 and left armrest 40 have cushioning material made of urethane foam or the like, and are used as elbow rests for the operator.

[0030] The left console 41 is located in front of the left armrest 40. The left console 41 is equipped with a steering control device 42. The steering control device 42 is located inside the cab 5. The steering control device 42 is located to the left of the driver's seat 31. The steering control device 42 is operated by an operator seated in the cab 5 to rotate the front frame 11 and the rear frame 12. The steering control device 42 is operated by an operator seated in the driver's seat 31 to operate the steering actuator 21.

[0031] The steering control device 42 includes a joystick 43. The joystick 43 protrudes upward from the upper surface of the left console 41. The joystick 43 has a lever shape. The joystick 43 accepts operator input. The operator sets the angle of bending of the front frame 11 relative to the rear frame 12 by grasping the joystick 43 with their left hand and tilting it left or right.

[0032] Figure 3 is a schematic diagram of a wheel loader 1 in a bent state, viewed from above. The bending of the front frame 11 relative to the rear frame 12 is achieved by extending and retracting the steering actuators 21 connected to the front frame 11 and the rear frame 12. The vehicle body bending angle shown in Figure 3 is the angle at which the front frame 11 bends relative to the rear frame 12. When the wheel loader 1 is in a straight line, the vehicle body bending angle is 0 degrees. When either the left or right steering actuator 21 extends and the other contracts, the vehicle body bending angle becomes greater than 0 degrees. The bending of the front frame 11 relative to the rear frame 12 shown in Figure 3 is achieved by the right steering actuator 21 extending and the left steering actuator 21 contracting.

[0033] Figure 4 is a schematic diagram showing a linkage mechanism that transmits the current vehicle body bending angle to the steering control device 42. The linkage mechanism includes a first link member 91 and a second link member 92.

[0034] The first link member 91 and the second link member 92 are rod-shaped members. The front end of the second link member 92 is rotatably connected to a bracket fixed to the front frame 11. The rear end of the second link member 92 and the front end of the first link member 91 are rotatably connected. The rectangle formed by the connecting shaft portion 13, the front end of the second link member 92, the rear end of the second link member 92, and the rear end of the first link member 91 is a parallelogram, forming a parallel link. The mechanical link mechanism connects from the front frame 11 to the steering control device 42 inside the cab 5.

[0035] <Configuration of the steering control device 42> The details of the configuration of the steering control device 42 of this embodiment will be described below. Figure 5 is a perspective view showing the configuration of the steering control device 42. Figure 6 is a perspective view of the joystick 43 from a different angle. Figure 7 is a cross-sectional view of the steering control device 42. Figure 8 is a plan view of the steering control device 42.

[0036] The operator tilts the joystick 43 left or right (Y direction). Tilting the joystick 43 to the right (YR direction) sets the vehicle frame 2 to bend so that the front frame 11 tilts to the right relative to the rear frame 12. Tilting the joystick 43 to the left (YL direction) sets the vehicle frame 2 to bend so that the front frame 11 tilts to the left relative to the rear frame 12. The angle of the front frame 11 relative to the rear frame 12 is set according to the angle of tilt of the joystick 43 from the neutral position.

[0037] The joystick 43 has a knob portion 44 at its tip. The knob portion 44 is provided with a switch portion 45 that is operated by the operator with their finger. The switch portion 45 includes, for example, a horn operation button 46 that is pressed to sound the horn. The switch portion 45 includes, for example, a speed gear selector switch 47 that is operated to switch the transmission speed gear when the wheel loader 1 is traveling. The speed gear selector switch 47 has a shift up button 47U that is pressed to shift the transmission speed gear up, and a shift down button 47D that is pressed to shift the transmission speed gear down. The switch portion 45 includes, for example, a forward / reverse selector switch 48 that is operated to switch the forward, reverse, and neutral positions of the wheel loader 1.

[0038] The steering control device 42 includes a knob wire 49. The knob wire 49 extends from inside to outside the joystick 43. One end of the knob wire 49 is electrically connected to the switch section 45. The knob wire 49 corresponds to an example of a first wire.

[0039] The steering control device 42 includes a support 50. The support 50 supports a joystick 43 so that it is movable relative to the support 50. The support 50 is mounted on the left console 41. The joystick 43 rotates relative to the left console 41. A fixing clamp 58 is fixed to the support 50.

[0040] The steering control device 42 includes two electric levers (steering switches). Specifically, the steering control device 42 includes a first electric lever 60 and a second electric lever 65.

[0041] The first electric lever 60 includes a first main body 61 and a first lever portion 62 that is tiltable relative to the first main body 61. The first lever portion 62 has a first core portion 63C protruding from the first main body 61 and a first spacer 63S surrounding the first core portion 63C. One end of the first lever wire 64 is connected to the first main body 61. The first lever wire 64 corresponds to an example of a second wire. The first electric lever 60 has a sensor that detects the tilt angle of the first lever portion 62 relative to the first main body 61. The first electric lever 60 outputs an electrical signal indicating the tilt angle of the first lever portion 62 relative to the first main body 61 to the outside via the first lever wire 64.

[0042] The second electric lever 65 includes a second main body 66 and a second lever portion 67 that is tiltable relative to the second main body 66. The second lever portion 67 has a second core portion 68C protruding from the second main body 66 and a second spacer 68S surrounding the second core portion 68C. One end of the second lever wire 69 is connected to the second main body 66. The second lever wire 65 corresponds to an example of the second wire. The second electric lever 65 has a sensor that detects the tilt angle of the second lever portion 67 relative to the second main body 66. The second electric lever 65 outputs an electrical signal indicating the tilt angle of the second lever portion 67 relative to the second main body 66 to the outside via the second lever wire 69.

[0043] The first core portion 63C and the second core portion 68C are made of, for example, a metal material. The first spacer 63S and the second spacer 68S are made of, for example, a metal material.

[0044] The steering control device 42 includes a movable part 70. The movable part 70 moves relative to the support part 50 in conjunction with the joystick 43 as the operator tilts the joystick 43. The movable part 70 mainly consists of a base part 71, a flange part 72, a sleeve part 73, a holding part 74, and a movable clamp 78.

[0045] A first connector 75 is provided on the base portion 71. The first lever wire 64 is connected to the first connector 75. A second connector 76 is provided on the base portion 71. The second lever wire 69 is connected to the second connector 76.

[0046] The holding part 74 holds the first body part 61 of the first electric lever 60 and the second body part 66 of the second electric lever 65. The first body part 61 of the first electric lever 60 and the second body part 66 of the second electric lever 65 operate integrally with the movable part 70. Therefore, the first body part 61 and the second body part 66 operate integrally with the joystick 43 as the operator tilts the joystick 43. The first body part 61 and the second body part 66 rotate relative to the left console 41.

[0047] The first lever wire 64 and the second lever wire 69 are inserted into the wire sleeve 79 and wired through the wire sleeve 79. The movable clamp 78 bundles the knob wire 49 and the wire sleeve 79. The movable clamp 78 bundles the knob wire 49, the first lever wire 64, and the second lever wire 69. Similarly, the fixed clamp 58 bundles the knob wire 49 and the wire sleeve 79, and bundles the knob wire 49, the first lever wire 64, and the second lever wire 69.

[0048] In the path of the knob wire 49, the movable clamp 78 bundles the knob wire 49, the first lever wire 64, and the second lever wire 69 at a position closer to the joystick 43 than the fixed clamp 58. In the path of the first lever wire 64, the movable clamp 78 bundles the knob wire 49, the first lever wire 64, and the second lever wire 69 at a position closer to the first electric lever 60 than the fixed clamp 58. In the path of the second lever wire 69, the movable clamp 78 bundles the knob wire 49, the first lever wire 64, and the second lever wire 69 at a position closer to the second electric lever 65 than the fixed clamp 58.

[0049] The flange portion 72 is fixed to the base portion 71 and also to the base end of the joystick 43. The flange portion 72 has a plate-like shape and has a through hole that penetrates in the thickness direction, as shown in Figure 7. The sleeve portion 73, the frame portion 80, and the transmission member 96 are arranged within the through hole of the flange portion 72.

[0050] The frame portion 80 is attached to the left console 41. The frame portion 80 has a roughly hollow cylindrical shape. A cylindrical shaft-shaped transmission member 96 is inserted inside the frame portion 80. The internal bearing 82 rotatably supports the transmission member 96 relative to the frame portion 80. The inner ring of the internal bearing 82 is attached to the outer circumferential surface of the transmission member 96, and the outer ring of the internal bearing 82 is attached to the inner circumferential surface of the frame portion 80.

[0051] One end of the transmission member 96 (the rightmost end in Figure 7) is connected to the first link member 91 shown in Figure 4. A mechanical linkage mechanism is formed, connecting the front frame 11 to the steering control device 42 via the second link member 92, the first link member 91, and the transmission member 96. Through this linkage mechanism, the current angle of the front frame 11 relative to the rear frame 12, i.e., the current vehicle body bending angle (Figure 3), is mechanically transmitted from the front frame 11 to the steering control device 42. The transmission member 96 corresponds to an example of a link.

[0052] A sleeve portion 73 is positioned on the outer circumference of a cylindrical frame portion 80. The outer bearing 81 rotatably supports the sleeve portion 73 relative to the frame portion 80. The inner ring of the outer bearing 81 is attached to the outer surface of the frame portion 80, and the outer ring of the outer bearing 81 is attached to the sleeve portion 73.

[0053] The joystick 43, flange portion 72, and sleeve portion 73 are configured to operate as a single unit. The joystick 43 is rotatable relative to the frame portion 80. The transmission member 96 is rotatable relative to the frame portion 80. The joystick 43 and the transmission member 96 are rotatable independently relative to the frame portion 80. The rotation of the joystick 43 relative to the frame portion 80 does not affect the operation of the transmission member 96. Furthermore, the rotation of the transmission member 96 relative to the frame portion 80 does not affect the operation of the joystick 43. The external bearing 81 supports the joystick 43 so that it is rotatable relative to the transmission member 96.

[0054] The transmission member 96 is positioned to pass through the connecting portion 100. The other end of the transmission member 96 (the left end in Figure 7) is positioned to abut against the input portion 110. The bolt 97 passes through the input portion 110 and is fixed to the transmission member 96. The transmission member 96 and the input portion 110 are fitted together and connected integrally by the bolt 97. The bolt 98 fits the input portion 110 and the connecting portion 100, thereby making the connection between the input portion 110 and the transmission member 96 even stronger.

[0055] In the cross-sectional view shown in Figure 7, the input section 110 has an L-shape. The L-shaped input section 110 has a first side extending in the vertical direction (vertical direction in Figure 7) and a second side extending in the front-to-back direction (X direction; left-to-right direction in Figure 7). The first side of the input section 110 is connected to the transmission member 96 by a bolt 97. The second side of the input section 110 has two elongated holes 111 and 112. The elongated holes 111 and 112 are formed by penetrating the plate-shaped input section 110 in the thickness direction. Referring also to Figure 8, the elongated holes 111 and 112 extend in the front-to-back direction (X direction). The elongated holes 111 and 112 extend in a direction perpendicular to the left-to-right direction (Y direction), which is the direction in which the operator tilts the joystick 43.

[0056] The first lever portion 62 of the first electric lever 60 is located in the elongated hole 111. The second lever portion 67 of the second electric lever 65 is located in the elongated hole 112. The steering control device 42 has two electric levers (first electric lever 60, second electric lever 65). The input section 110 has the same number of elongated holes 111, 112 as the electric levers. The lever portion of each electric lever is located in a different elongated hole.

[0057] The first electric lever 60 and the second electric lever 65 are positioned side by side in the front-to-back direction (X direction), which is perpendicular to the left-to-right direction (Y direction) in which the operator tilts the joystick 43. The first electric lever 60, the second electric lever 65, and the joystick 43 are positioned in this order in the front-to-back direction (X direction). The first electric lever 60 and the second electric lever 65 are positioned away from the joystick 43 in the front-to-back direction (X direction).

[0058] In the top-down plan view shown in Figure 8, the elongated holes 111 and 112 have an elongated shape with their longitudinal direction in the front-to-back direction (X direction) and their shortened direction in the left-to-right direction (Y direction). The periphery of the elongated holes 111 and 112 shown in Figure 8 is a closed curve.

[0059] The distance between the outer surface of the first lever portion 62 (first spacer 63S) and the periphery of the elongated hole 111 is maximum in the front-to-back direction (X direction) and minimum in the left-to-right direction (Y direction). The distance between the first lever portion 62 (first spacer 63S) and the periphery of the elongated hole 111 in the front-to-back direction (X direction) is greater than the distance between the first lever portion 62 (first spacer 63S) and the periphery of the elongated hole 111 in the left-to-right direction (Y direction).

[0060] The distance between the outer surface of the second lever portion 67 (second spacer 68S) and the periphery of the elongated hole 112 is maximum in the front-to-back direction (X direction) and minimum in the left-to-right direction (Y direction). The distance between the second lever portion 67 (second spacer 68S) and the periphery of the elongated hole 112 in the front-to-back direction (X direction) is greater than the distance between the second lever portion 67 (second spacer 68S) and the periphery of the elongated hole 112 in the left-to-right direction (Y direction).

[0061] The periphery of the elongated holes 111 and 112 does not necessarily have to be a closed curve. The elongated holes 111 and 112 can be elongated gaps extending in the front-to-back direction (X direction). The elongated hole 111 may extend to the edge of the input section 110 and open at the edge of the input section 110. The elongated hole 112 may extend to the edge of the input section 110 and open at the edge of the input section 110. The elongated holes 111 and 112 may be in communication with each other.

[0062] The first spacer 63S of the first lever portion 62 has a hollow cylindrical shape. The second spacer 68S of the second lever portion 67 has a hollow cylindrical shape. The first spacer 63S and the second spacer 68S extend in the vertical direction. The first spacer 63S passes through the elongated hole 111. The second spacer 68S passes through the elongated hole 112. The first spacer 63S and the second spacer 68S pass through the plate-shaped input portion 110 in the thickness direction. The axial length of the first spacer 63S and the second spacer 68S is greater than the thickness of the plate-shaped input portion 110.

[0063] <Steering operation of wheel loader 1> The operation of changing the body bending angle (Figure 3) of the wheel loader 1 by operating the steering control device 42 described above, and thereby changing the direction of travel of the wheel loader 1, will be explained below.

[0064] When the operator seated in the driver's seat 31 tilts the joystick 43 left or right, the first main body 61 of the first electric lever 60 and the second main body 66 of the second electric lever 65 tilt left or right together with the joystick 43.

[0065] Meanwhile, the transmission member 96 rotates axially in the front-rear direction (X direction) according to the current vehicle body bending angle. The input unit 110, which is connected to the transmission member 96, moves left and right integrally with the transmission member 96 as the transmission member 96 rotates. The input unit 110 has elongated holes 111 and 112. The first lever unit 62 is positioned in the elongated hole 111. The second lever unit 67 is positioned in the elongated hole 112. The input unit 110, which moves left and right, presses the first lever unit 62 and the second lever unit 67 left and right. The input unit 110 inputs the current vehicle body bending angle transmitted by the transmission member 96 to the first lever unit 62 and the second lever unit 67. By pressing the first lever unit 62, the input unit 110 changes the angle at which the first lever unit 62 is inclined relative to the first main body 61. The input unit 110 changes the angle at which the second lever unit 67 is tilted relative to the second main unit 66 by pressing the second lever unit 67.

[0066] The first electric lever 60 and the second electric lever 65 are mechanically input to both the tilt angle of the joystick 43 from its neutral position and the current vehicle body bending angle. By tilting the joystick 43 from its neutral position, the first body portion 61 of the first electric lever 60 and the second body portion 66 of the second electric lever 65 move left and right in conjunction with the joystick 43, changing the tilt angle of the first lever portion 62 relative to the first body portion 61 and the tilt angle of the second lever portion 67 relative to the second body portion 66. According to the current vehicle body bending angle, the input unit 110 presses the first lever portion 62 of the first electric lever 60 and the second lever portion 67 of the second electric lever 65 left and right, changing the tilt angle of the first lever portion 62 relative to the first body portion 61 and the tilt angle of the second lever portion 67 relative to the second body portion 66.

[0067] If the angle set by the joystick 43 relative to the rear frame 12 differs from the current angle of the front frame 11 relative to the rear frame 12 that is fed back to the steering control device 42, the first lever portion 62 is positioned at an angle relative to the first main body portion 61, and the second lever portion 67 is positioned at an angle relative to the second main body portion 66. An electrical signal indicating the angle of inclination of the first lever portion 62 relative to the first main body portion 61 is output to the outside via the first lever wire 64. An electrical signal indicating the angle of inclination of the second lever portion 67 relative to the second main body portion 66 is output to the outside via the second lever wire 69.

[0068] These electrical signals are input to a controller (not shown). The controller generates a control signal that commands the angle of the front frame 11 relative to the rear frame 12 in response to the input electrical signals. The controller outputs this control signal to the steering actuator 21 to control the steering actuator 21. More specifically, the controller extends and retracts the left and right steering actuators 21 so that the vehicle body bending angle approaches the set angle of the front frame 11 relative to the rear frame 12.

[0069] For example, when the wheel loader 1 is traveling in a straight line, the angle of the front frame 11 relative to the rear frame 12 is zero degrees, and at this time the input unit 110 does not tilt the first lever unit 62 and the second lever unit 67 to the left or right.

[0070] From this state, when the operator tilts the joystick 43 to the right, the first main body 61 of the first electric lever 60 and the second main body 66 of the second electric lever 65 move in conjunction with the joystick 43. Because it takes time for the steering actuator 21 to move in response to the operation of the joystick 43, the angle of the front frame 11 relative to the rear frame 12 remains at zero degrees. The angle of tilt of the joystick 43 from its neutral position becomes the angle difference between the current angle of the front frame 11 relative to the rear frame 12 and the set angle of the front frame 11 relative to the rear frame 12. The angle of tilt of the joystick 43 from its neutral position becomes the inclination angle of the first lever portion 62 relative to the first main body 61, and the inclination angle of the second lever portion 67 relative to the second main body 66.

[0071] Upon receiving electrical signals indicating these tilt angles, the controller extends the left steering actuator 21 and retracts the right steering actuator 21, bending the front frame 11 to the right relative to the rear frame 12. This changes the body bending angle of the wheel loader 1. The body bending angle increases from zero degrees, approaching the set angle of the front frame 11 relative to the rear frame 12.

[0072] The current vehicle body bending angle is fed back to the steering control device 42 via a mechanical linkage mechanism. When the front frame 11 bends to the right relative to the rear frame 12, and the vehicle body bending angle changes, the input unit 110 presses the first lever unit 62 and the second lever unit 67, tilting them to the right. The tilt angle of the first lever unit 62 relative to the first main body unit 61 decreases, and the tilt angle of the second lever unit 67 relative to the second main body unit 66 decreases.

[0073] Control is performed to adjust the amount of extension and retraction of the steering actuator 21 until the vehicle body bending angle becomes equal to the set angle of the front frame 11 relative to the rear frame 12.

[0074] When the vehicle body bending angle becomes equal to the set angle of the front frame 11 relative to the rear frame 12, the first lever portion 62 stops tilting relative to the first main body portion 61, and the second lever portion 67 stops tilting relative to the second main body portion 66. The tilt angle of the first lever portion 62 relative to the first main body portion 61 output from the first electric lever 60 becomes zero, and the tilt angle of the second lever portion 67 relative to the second main body portion 66 output from the second electric lever 65 becomes zero. Upon receiving these electrical signals indicating zero tilt angles, the controller stops the extension and retraction of the steering actuator 21 and maintains the current amount of extension and retraction of the steering actuator 21. As a result, the bending movement of the front frame 11 relative to the rear frame 12 stops, and the vehicle body bending angle is maintained at the set angle.

[0075] <Mechanism of Action and Effects> Although some of the above description overlaps with the above, the characteristic configuration and effects of the work machine of this embodiment are summarized as follows.

[0076] As shown in Figures 5,7-8, the steering control device 42 includes a joystick 43, a first electric lever 60, and an input unit 110. The joystick 43 accepts operator input to set the angle of the front frame 11 relative to the rear frame 12 of the wheel loader 1. The first electric lever 60 has a first body 61 and a first lever portion 62 that is tiltable relative to the first body 61. The first electric lever 60 outputs the tilt angle of the first lever portion 62 relative to the first body 61. The input unit 110 inputs an input to the first lever portion 62 of the first electric lever 60 to tilt the first lever portion 62 relative to the first body 61. The input unit 110 has an elongated hole 111 extending in the front-rear direction (X direction). The first lever portion 62 is located within the elongated hole 111.

[0077] When a force is applied to move the input unit 110 in the left-right direction (Y direction), which is the direction of operation of the joystick 43, a force is applied from the input unit 110 to the first lever unit 62, causing the first lever unit 62 to tilt relative to the first main body unit 61. When a force is applied to move the input unit 110 in the front-back direction (X direction), which is perpendicular to the direction of operation of the joystick 43, the first lever unit 62 can move relative to the input unit 110 along the elongated hole 111.

[0078] The first electric lever 60 may not have sufficient strength to withstand tilting of the first lever portion 62 in a direction different from the originally intended tilting direction of the first lever portion 62 relative to the first main body portion 61. Even in this case, the first lever portion 62 can move relative to the input portion 110 in that different direction, thus preventing the first lever portion 62 from tilting in that different direction. Therefore, the occurrence of failures of the first electric lever 60 can be suppressed, and the reliability of the steering control device 42 can be improved.

[0079] As shown in Figure 7, the first lever portion 62 has a first core portion 63C protruding from the first main body portion 61 and a first spacer 63S surrounding the first core portion 63C. An input from the input portion 110 that tilts the first lever portion 62 relative to the first main body portion 61 acts on the first spacer 63S, causing the first core portion 63C to tilt relative to the first main body portion 61 together with the first spacer 63S.

[0080] Since the first spacer 63S is interposed between the first core portion 63C and the periphery of the elongated hole 111, even if a misalignment of the first core portion 63C relative to the input portion 110 occurs in the left-right direction, the input to tilt the first lever portion 62 can be reliably input from the input portion 110 to the first lever portion 62. Since the first spacer 63S is positioned through the elongated hole 111, even if a misalignment of the first core portion 63C relative to the input portion 110 occurs in the direction in which the first lever portion 62 protrudes from the first main body portion 61, the input to tilt the first lever portion 62 can be reliably input from the input portion 110 to the first lever portion 62. Therefore, the reliability of the steering control device 42 can be improved.

[0081] When a force is applied that moves the input section 110 in the extending direction of the first lever section 62, the first lever section 62 can move relative to the input section 110. The first lever section 62 may not have sufficient strength against loads acting on it in the direction in which it protrudes from the first main body section 61. Even in this case, the first lever section 62 can move relative to the input section 110 in the direction of protrusion, so it is possible to avoid loads acting on the first lever section 62 in the direction of protrusion. Therefore, it is possible to suppress the occurrence of failures of the first electric lever 60.

[0082] As shown in Figures 5,7-8, the joystick 43 and the first lever portion 62 are positioned apart in the front-to-back direction (X direction). Since the joystick 43 is not directly attached to the first lever portion 62, even if an operation is made to tilt the joystick 43 in a direction different from its intended tilt direction (left-to-right direction) (for example, in the front-to-back direction), the force generated by that operation of the joystick 43 is not directly transmitted to the first lever portion 62. This reliably prevents the first lever portion 62 from tilting in a direction different from the originally intended tilt direction of the first lever portion 62 relative to the first main body portion 61, thereby suppressing the occurrence of failures of the first electric lever 60.

[0083] As shown in Figures 4 and 7, the transmission member 96 mechanically transmits the current angle of the front frame 11 relative to the rear frame 12 to the steering control device 42. The input unit 110 is connected to the transmission member 96. The current vehicle body bending angle is fed back to the steering control device 42 via the transmission member 96. The input unit 110 inputs the current vehicle body bending angle transmitted by the transmission member 96 to the first lever portion 62 of the first electric lever 60. The first electric lever 60 outputs the inclination angle of the first lever portion 62 relative to the first main body portion 61, based on the angle difference between the set angle of the front frame 11 relative to the rear frame 12, which is determined by the operation of the joystick 43, and the current vehicle body bending angle. By appropriately controlling the steering actuator 21 based on this inclination angle, the angle of the front frame 11 relative to the rear frame 12 can be easily adjusted to the set value.

[0084] As shown in Figure 7, the steering control device 42 includes an external bearing 81. The external bearing 81 supports the joystick 43 so that it can rotate relative to the transmission member 96. The configuration is such that the joystick 43 is not directly attached to the first lever portion 62, as it is held by the external bearing 81. The external bearing 81 receives the force generated by the operation of the joystick 43 to tilt it in a direction different from its original tilt direction (left-right direction) (for example, the front-back direction), making it impossible to tilt the joystick 43 in that different direction. This reliably prevents the first lever portion 62 from tilting in a direction different from the originally intended tilt direction of the first lever portion 62 relative to the first main body portion 61, thereby suppressing the occurrence of failures of the first electric lever 60.

[0085] As shown in Figure 7, the transmission member 96 rotates with the front-to-back direction (X direction) as its axial direction. An input unit 110 is connected to the transmission member 96, and the rotation of the transmission member 96 is input to the first lever unit 62 via the input unit 110. This allows the first lever unit 62 to be reliably tilted in the left-to-right direction relative to the first main body unit 61, which is the direction in which the joystick 43 is tilted.

[0086] As shown in Figures 5,7-8, the steering control device 42 has a first electric lever 60 and a second electric lever 65. The input section 110 has an elongated hole 111 and an elongated hole 112. The first lever portion 62 of the first electric lever 60 is located in the elongated hole 111. The second lever portion 67 of the second electric lever 65 is located in the elongated hole 112. Since the steering control device 42 has multiple electric levers and is redundant, the reliability of the steering control device 42 is improved.

[0087] When a force is applied to move the input section 110 in a direction perpendicular to the direction of operation of the joystick 43, the first lever section 62 can move relative to the input section 110 along the elongated hole 111, and the second lever section 67 can move relative to the input section 110 along the elongated hole 112. This suppresses the occurrence of failures of the first electric lever 60 and the second electric lever 65. Since the first electric lever 60 is located in the elongated hole 111 which extends in the front-rear direction, and the second electric lever 65 is located in the elongated hole 112 which extends in the front-rear direction, a misalignment of the relative positions of the first electric lever 60 and the second electric lever 65 in the front-rear direction is permitted.

[0088] As shown in Figures 5,7-8, the first electric lever 60 and the second electric lever 65 are arranged side by side in the front-to-back direction (X direction). The first lever portion 62 is located in the elongated hole 111, and an input to tilt the first lever portion 62 is input to the first lever portion 62 from the periphery of the elongated hole 111. The second electric lever 65 is located in the elongated hole 112, and an input to tilt the second lever portion 67 is input to the second lever portion 67 from the periphery of the elongated hole 112. As a result, even if the positions of the first electric lever 60 and the second electric lever 65 are misaligned in the left-to-right direction, this misalignment can be absorbed, and the input from the input unit 110 can cause the first lever portion 62 and the second lever portion 67 to be tilted in the same way.

[0089] In the above description of the embodiment, an example was given in which the input unit 110 is connected to the transmission member 96 and the main body of the electric lever and the joystick 43 operate as a single unit. However, the example is not limited to this, and the main body of the electric lever and the transmission member 96 may operate as a single unit, and the vehicle body bending angle that is fed back may be transmitted as the tilt of the main body. The input unit 110 may also be connected to the joystick 43, and the lever portion of the electric lever may tilt in accordance with the tilt of the joystick 43. The lever portion of the electric lever and the joystick 43 do not necessarily have to be positioned far apart in the front-rear direction, and the joystick 43 may be directly attached to the lever portion.

[0090] Even in such cases, because the lever portion of the electric lever is positioned within an elongated hole extending in the front-to-back direction, when a force acting on the joystick 43 to tilt it in the front-to-back direction, the lever portion can move relative to the joystick 43 in the front-to-back direction. Since tilting of the lever portion in the front-to-back direction can be avoided, the occurrence of malfunctions of the electric lever can be suppressed.

[0091] In the above description of the embodiment, a wheel loader 1 is given as an example of a work machine, but it is also applicable to other types of work machines such as articulated dump trucks and motor graders.

[0092] <Note> The above description includes the following features.

[0093] (Note 1) A vehicle body frame having a rear frame and a front frame rotatably connected to the rear frame, A steering actuator that changes the angle of the front frame relative to the rear frame, The steering actuator is operated by an operator and includes a steering control device. The steering control device is A joystick that accepts operator input, An electric lever having a main body and a lever that can be tilted relative to the main body, and outputting the tilt angle of the lever relative to the main body, The input unit includes input to the lever unit that causes the lever unit to tilt relative to the main body unit, The input section has at least one elongated hole extending in a direction perpendicular to the direction in which the operator tilts the joystick, The lever portion is positioned within the elongated hole in the working machine.

[0094] (Note 2) The lever portion comprises a core portion protruding from the main body portion and a spacer surrounding the core portion, as described in Appendix 1 of the working machine.

[0095] (Note 3) The work machine according to Appendix 1 or Appendix 2, wherein the joystick and the lever portion are arranged separately in the orthogonal direction.

[0096] (Note 4) The system further includes a link that mechanically transmits the current angle of the front frame relative to the rear frame to the steering control device. The input unit is connected to either the link or the joystick, and is a work machine as described in any one of the appendices 1 to 3.

[0097] (Note 5) The working machine according to Appendix 4, wherein the steering device further includes a bearing that supports the joystick so as to be rotatable relative to the link.

[0098] (Note 6) The link is a working machine as described in Appendix 4 or Appendix 5, which rotates with the orthogonal direction as its axial direction.

[0099] (Note 7) The aforementioned at least one electric lever has a plurality of electric levers, The input section has the same number of elongated holes as the electric lever, The work machine according to any one of the appendices 1 to 6, wherein the lever portion of each of the aforementioned electric levers is arranged in a different elongated hole.

[0100] (Note 8) The work machine described in Appendix 7, wherein the plurality of electric levers are arranged in the orthogonal directions.

[0101] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the invention is indicated by the claims rather than by the foregoing description, and all modifications within the meaning and scope equivalent to the claims are intended. [Explanation of Symbols]

[0102] 1 Wheel loader, 2 Body frame, 3 Work equipment, 4,7 Driving wheels, 5 Cab, 11 Front frame, 12 Rear frame, 13 Connecting shaft section, 14 Boom, 15 Bucket, 21 Steering cylinder, 31 Driver's seat, 40 Left armrest, 41 Left console, 42 Steering control device, 43 Joystick, 44 Knob section, 45 Switch section, 46 Horn control button, 47 Speed ​​gear selector switch, 47D Shift down button, 47U Shift up button, 48 Forward / reverse selector switch, 49 Knob wire, 50 Support section, 58 Fixing clamp, 60 First electric lever, 61 First main body section, 62 First lever section, 63C First core section, 63S First spacer, 64 First lever wire, 65 Second electric lever, 66 Second main body section, 67 Second lever section, 68C Second core section, 68S 69 Second spacer, 70 Second lever wire, 71 Movable part, 72 Base part, 73 Flange part, 74 Sleeve part, 75 Holding part, 76 First connector, 78 Second connector, 79 Movable clamp, 80 Wire sleeve, 80 Frame part, 81 Outer bearing, 82 Inner bearing, 91 First link member, 92 Second link member, 96 Transmission member, 97, 98 Bolt, 100 Connecting part, 110 Input part, 111, 112 Slotted hole, X Front-back direction, Y Left-right direction.

Claims

1. A vehicle body frame having a rear frame and a front frame rotatably connected to the rear frame, A steering actuator that changes the angle of the front frame relative to the rear frame, The steering actuator is operated by an operator and includes a steering control device. The steering control device is A joystick that accepts operator input, An electric lever having a main body and a lever that can be tilted relative to the main body, and outputting the tilt angle of the lever relative to the main body, The input unit includes input to the lever unit that causes the lever unit to tilt relative to the main body unit, The input section has at least one elongated hole extending in a direction perpendicular to the direction in which the operator tilts the joystick, The lever portion is positioned within the elongated hole in the working machine.

2. The work machine according to claim 1, wherein the lever portion has a core portion protruding from the main body portion and a spacer surrounding the core portion.

3. The work machine according to claim 1 or claim 2, wherein the joystick and the lever portion are arranged apart in the orthogonal direction.

4. The system further includes a link that mechanically transmits the current angle of the front frame relative to the rear frame to the steering control device. The work machine according to claim 1 or claim 2, wherein the input unit is connected to either the link or the joystick.

5. The working machine according to claim 4, wherein the steering device further includes a bearing that supports the joystick so as to be rotatable relative to the link.

6. The work machine according to claim 4, wherein the link rotates with the orthogonal direction as its axial direction.

7. The aforementioned at least one electric lever has a plurality of electric levers, The input section has the same number of elongated holes as the electric lever, The working machine according to claim 1 or claim 2, wherein the lever portion of each of the electric levers is arranged in different elongated holes.

8. The work machine according to claim 7, wherein the plurality of electric levers are arranged in the orthogonal direction.

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