JP7798660B2 - Work machinery - Google Patents

Description

This disclosure relates to a work machine.

JP 2020-26230 A (Patent Document 1) discloses a steering device for operating an articulated work vehicle. The joystick lever is configured to be rotatable relative to a base member or support. A lever angle sensor detects the angle of the joystick lever relative to the support. A vehicle frame angle sensor detects the rotation angle of the front frame relative to the rear frame. A controller controls an electromagnetic pilot valve based on the detection values of the lever angle sensor and the vehicle frame angle sensor. The electromagnetic pilot valve adjusts the pilot oil pressure supplied to the hydraulic valve. The hydraulic valve adjusts the flow rate of oil supplied to the steering cylinder according to the input pilot oil pressure.

Japanese Patent Application Laid-Open No. 2020-26230

Instead of a pilot valve that supplies pilot oil pressure to a hydraulic valve, a steering operation device is being devised that includes an electric lever that detects joystick operation. An electric signal corresponding to the joystick operation is output from the electric lever to a controller, and the controller controls the steering actuator in accordance with the received electric signal.

The electrical wires connected to the steering operation device can become deformed when the joystick is operated. It is necessary to provide some space for movement for these wires, and it is desirable to reduce this space in order to make the steering operation device more compact.

This disclosure proposes a work machine that reduces the moving space of the steering operation device.

A work machine according to the present disclosure includes a body frame, a steering actuator, and a steering operation 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 operation device is operated by an operator to operate the steering actuator. The steering operation device includes a joystick and at least one electric lever. The joystick accepts operation by the operator. The electric lever has a main body portion and a lever portion that can be tilted relative to the main body portion. The electric lever outputs the tilt angle of the lever portion relative to the main body portion. The joystick and main body portion operate integrally.

The work machine disclosed herein allows for a reduction in the space required for the steering operation device to move.

1 is a side view of a wheel loader as an example of a work machine based on an embodiment. FIG. FIG. 2 is a perspective view showing the structure around the driver's seat in the cab. FIG. 1 is a schematic plan view of a wheel loader in a bent state. 3 is a schematic diagram showing a link mechanism that transmits the current vehicle body bending angle to a steering operation device. FIG. FIG. 2 is a perspective view showing the configuration of a steering operation device. 10A and 10B are perspective views of the joystick from different angles. FIG. 2 is a cross-sectional view of a steering operation device. FIG. 2 is a plan view of the steering operation device. FIG. 2 is a front view of the steering operation device with the joystick in a neutral position. FIG. 2 is a front view of the steering operation device with the joystick tilted to the left. FIG. 2 is a front view of the steering operation device with the joystick tilted to the right.

The following describes the embodiments with reference to the accompanying drawings. In the following description, identical components are designated by the same reference numerals. Their names and functions are also the same. Therefore, detailed descriptions of them will not be repeated.

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

As shown in FIG. 1, the wheel loader 1 comprises a body frame 2, a work implement 3, a traveling device, a cab 5, and an engine hood 6. The body frame 2, cab 5, etc. make up the body (work machine body) of the wheel loader 1. The work implement 3 and traveling device are attached to the body of the wheel loader 1.

The traveling gear allows the body of the wheel loader 1 to travel, and includes traveling wheels 4, 7. The wheel loader 1 is a wheeled vehicle equipped with traveling wheels 4, 7 on both the left and right sides of the body as rotating bodies for traveling. The wheel loader 1 is self-propelled by driving the traveling wheels 4, 7 to rotate, and can perform desired tasks such as excavating and loading earth and sand using the work implement 3.

In this specification, the direction in which the wheel loader 1 travels straight ahead is referred to as the fore-and-aft direction of the wheel loader 1. In the fore-and-aft direction of the wheel loader 1, the side on which the work implement 3 is arranged relative to the vehicle body frame 2 is referred to as the front direction, and the side opposite the front direction is referred to as the rear direction. The left-and-right direction of the wheel loader 1 is the direction perpendicular to the fore-and-aft direction when the wheel loader 1 is viewed from above on flat ground. Looking forward, the right and left sides of the left-and-right direction are the right direction and left direction, respectively. The up-and-down direction of the wheel loader 1 is the direction perpendicular to the plane defined by the fore-and-aft direction and the left-and-right direction. In the up-and-down direction, the side with the ground facing is the bottom side, and the side with the sky facing is the top side.

In the drawings, the X direction indicated by the double arrow in Figure 1 is the front-to-back direction. The XF direction is the front direction, and the XR direction is the rear direction. The Y direction shown in the drawings described below is the left-to-right direction. The YL direction is the left direction, and the YR direction is the right direction.

The vehicle body frame 2 includes a front frame 11 and a rear frame 12. The front frame 11 is disposed in front of the rear frame 12. The front frame 11 is connected to the rear frame 12 so that it can be bent. The front frame 11 is rotatably connected to the rear frame 12 by a connecting shaft 13. The connecting shaft 13, which forms the center of rotation of the front frame 11 relative to the rear frame 12, is an axis that extends in the vertical direction. The connecting shaft 13 is located in the center of the vehicle body frame 2 in the left-right direction. The front frame 11 and rear frame 12 form the vehicle body frame 2 with an articulated structure. The wheel loader 1 is an articulated work machine in which the front frame 11 and rear frame 12 are connected.

The front frame 11 and rear frame 12 are connected by a steering actuator 21. The steering actuator 21 is arranged across the front frame 11 and the rear frame 12. The base end of the steering actuator 21 is attached to the rear frame 12. The tip end of the steering actuator 21 is attached to the front frame 11. A pair of steering actuators 21 are provided, one on the left and one on the right. The steering actuators 21 are arranged side by side on both sides of the connecting shaft 13 in the left-right direction.

When the steering actuator 21 is driven to extend and retract, the front frame 11 moves left and right relative to the rear frame 12 around the connecting shaft 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 relative to the rear frame 12. The extension and contraction of the steering actuator 21 changes the angle of bending of the front frame 11 relative to the rear frame 12.

A work implement 3 and a pair of left and right running wheels (front wheels) 4 are attached to the front frame 11. The work implement 3 is disposed at the front of the vehicle body and is supported by the vehicle body of the wheel loader 1. The work implement 3 includes a boom 14 and a bucket 15. The bucket 15 is located at the tip of the work implement 3. The bucket 15 is a work tool used for excavating and loading.

The work implement 3 includes boom cylinders 16. The front frame 11 and the boom 14 are connected by a pair of boom cylinders 16. The base ends of the boom cylinders 16 are attached to the front frame 11. The tips of the boom cylinders 16 are attached to the boom 14. The boom cylinders 16 are hydraulic actuators that move the boom 14 up and down relative 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.

The work implement 3 further includes a bell crank 18, a connecting link 19, and a bucket cylinder 17. The bell crank 18 is rotatably supported on the boom 14 at approximately 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.

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.

Attached to the rear frame 12 are an engine hood 6, a cab 5 in which the operator sits, and a pair of left and right running wheels (rear wheels) 7. The engine hood 6 is located behind the cab 5. The engine hood 6 houses a hydraulic oil tank, engine, hydraulic pump, air cleaner, etc.

The box-shaped cab 5 is located behind the work implement 3. The cab 5 is mounted on the body frame 2. The cab 5 is mounted on the rear frame 12. The cab 5 defines an interior space for the operator. A door is provided on the left side of the cab 5, which is opened and closed when the operator enters and leaves the cab 5.

Figure 2 is a perspective view showing the structure around the driver's seat 31 inside the cab 5. Inside the cab 5, there is the driver's seat 31 where the operator sits, as well as operating devices that the operator operates to operate the wheel loader 1. The driver's seat 31 is located in an interior space defined by the cab 5. The operator sits in the driver's seat 31 in the cab 5 to operate the wheel loader 1. 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.

The seat cushion 33 is provided lying horizontally. The seat cushion 33 is the seat portion on which the operator sits. The seat back 32 is provided rising upward from the rear end of the seat cushion 33. The seat back 32 is the seat portion against which the operator rests. 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.

The suspension mechanism 35 is located between the floor of the cab 5 and the seat cushion 33 in the vertical direction. The suspension mechanism 35 elastically supports the seat cushion 33.

A right armrest 36 and a right console 37 are arranged inside the cab 5. The right armrest 36 and right console 37 are located to the right of the driver's seat 31. The right console 37 is provided with a work implement control lever 38, a dial device 39, and other devices. The work implement control lever 38 is operated to control the operation of the work implement 3. The dial device 39 is operated to control the travel of the wheel loader 1. The dial device 39 may be a vehicle speed limit dial that is operated to specify the maximum vehicle speed at which the wheel loader 1 can travel.

A left armrest 40 and a left console 41 are located inside the cab 5. The left armrest 40 and the 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 cab 5 door in the left-right direction. The right console 37 and the left console 41 are located higher than the seat cushion 33. The right armrest 36 and the left armrest 40 are located higher than the seat cushion 33. The right armrest 36 and the left armrest 40 have cushioning material such as urethane foam and are used as armrests for the operator.

The left console 41 is provided in front of the left armrest 40. A steering operation device 42 is provided on the left console 41. The steering operation device 42 is located inside the cab 5. The steering operation device 42 is located to the left of the driver's seat 31. The steering operation 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 operation device 42 is operated by an operator seated in the driver's seat 31 to operate the steering actuator 21.

The steering operation device 42 includes a joystick 43. The joystick 43 protrudes upward from the top surface of the left console 41. The joystick 43 has a lever shape. The joystick 43 accepts operation by the operator. The operator holds the joystick 43 in his left hand and tilts it left or right to set the angle of bending of the front frame 11 relative to the rear frame 12.

Figure 3 is a schematic plan view of the wheel loader 1 in a bent state. The front frame 11 is bent relative to the rear frame 12 by extending and retracting the steering actuators 21 connected to the front frame 11 and rear frame 12. The vehicle body bending angle shown in Figure 3 is the angle at which the front frame 11 is bent relative to the rear frame 12. When the wheel loader 1 is traveling straight, the vehicle body bending angle is 0 degrees. When one of the left and right steering actuators 21 extends and the other contracts, the vehicle body bending angle becomes an angle greater than 0 degrees. The front frame 11 is bent relative to the rear frame 12 shown in Figure 3 by extending the right steering actuator 21 and contracting the left steering actuator 21.

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

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 connecting the connecting shaft 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. A mechanical link mechanism connects the front frame 11 to the steering operation device 42 inside the cab 5.

<Configuration of steering operation device 42>
The configuration of the steering operation device 42 of the embodiment will be described in detail below. Fig. 5 is a perspective view showing the configuration of the steering operation device 42. Fig. 6 is a perspective view of the joystick 43 viewed from a different angle. Fig. 7 is a cross-sectional view of the steering operation device 42. Fig. 8 is a plan view of the steering operation device 42.

The operator tilts the joystick 43 left and right (Y direction). By tilting the joystick 43 rightward (YR direction), the body frame 2 is set to bend so that the front frame 11 tilts to the right relative to the rear frame 12. By tilting the joystick 43 leftward (YL direction), the body frame 2 is set 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 state.

The joystick 43 has a knob 44 at its tip. The knob 44 is provided with a switch 45 that is operated by the operator's finger. The switch 45 includes, for example, a horn operation button 46 that is pressed to sound the horn. The switch 45 includes, for example, a speed stage changeover switch 47 that is operated to change the transmission speed stage when the wheel loader 1 is traveling. The speed stage changeover switch 47 has a shift-up button 47U that is pressed to shift up the transmission speed stage, and a shift-down button 47D that is pressed to shift down the transmission speed stage. The switch 45 includes, for example, a forward/reverse changeover switch 48 that is operated to switch the travel of the wheel loader 1 between forward, reverse, and neutral.

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

The steering operation device 42 includes a support portion 50. The support portion 50 supports the joystick 43 so that it can move relative to the support portion 50. The support portion 50 is attached to the left console 41. The joystick 43 rotates relative to the left console 41. A fixing clamp 58 is fixed to the support portion 50.

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

The first electric lever 60 includes a first main body portion 61 and a first lever portion 62 that can be tilted relative to the first main body portion 61. The first lever portion 62 has a first core portion 63C that protrudes from the first main body portion 61 and a first spacer 63S that surrounds the periphery of the first core portion 63C. One end of a first lever electric wire 64 is connected to the first main body portion 61. The first lever electric wire 64 corresponds to an example of a second electric 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 portion 61. The first electric lever 60 outputs an electric signal that indicates the tilt angle of the first lever portion 62 relative to the first main body portion 61 to the outside via the first lever electric wire 64.

The second electric lever 65 includes a second main body portion 66 and a second lever portion 67 that can be tilted relative to the second main body portion 66. The second lever portion 67 has a second core portion 68C that protrudes from the second main body portion 66 and a second spacer 68S that surrounds the periphery of the second core portion 68C. One end of a second lever electric wire 69 is connected to the second main body portion 66. The second lever electric wire 65 corresponds to an example of a second electric 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 portion 66. The second electric lever 65 outputs an electric signal indicating the tilt angle of the second lever portion 67 relative to the second main body portion 66 to the outside via the second lever electric wire 69.

The first core 63C and the second core 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.

The steering operation device 42 includes a movable portion 70. The movable portion 70 moves relative to the support portion 50 together with the joystick 43 as the operator tilts the joystick 43. The movable portion 70 mainly includes a base portion 71, a flange portion 72, a sleeve portion 73, a holding portion 74, and a movable clamp 78.

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.

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

The first lever electric wire 64 and the second lever electric wire 69 are inserted into the electric wire sleeve 79 and routed through the electric wire sleeve 79. The movable clamp 78 bundles the knob electric wire 49 and the electric wire sleeve 79. The movable clamp 78 bundles the knob electric wire 49, the first lever electric wire 64, and the second lever electric wire 69. The fixed clamp 58 similarly bundles the knob electric wire 49 and the electric wire sleeve 79, and bundles the knob electric wire 49, the first lever electric wire 64, and the second lever electric wire 69.

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.

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

The frame section 80 is attached to the left console 41. The frame section 80 has a roughly hollow cylindrical shape. A cylindrical shaft-shaped transmission member 96 is inserted inside the frame section 80. The inner bearing 82 supports the transmission member 96 so that it can rotate relative to the frame section 80. The inner ring of the inner bearing 82 is attached to the outer peripheral surface of the transmission member 96, and the outer ring of the inner bearing 82 is attached to the inner peripheral surface of the frame section 80.

One end of the transmission member 96 (the right end in Figure 7) is connected to the first link member 91 shown in Figure 4. A mechanical link mechanism is configured that connects the front frame 11 to the steering operation device 42 via the second link member 92, the first link member 91, and the transmission member 96. Via this link 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 operation device 42. The transmission member 96 corresponds to an example of a link.

The sleeve portion 73 is disposed on the outer periphery of the cylindrical frame portion 80. The outer bearing 81 supports the sleeve portion 73 so that it can rotate relative to the frame portion 80. The inner ring of the outer bearing 81 is attached to the outer periphery of the frame portion 80, and the outer ring of the outer bearing 81 is attached to the sleeve portion 73.

The joystick 43, flange portion 72, and sleeve portion 73 are configured to operate integrally. 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 transmission member 96 are rotatable independently relative to the frame portion 80. Rotation of the joystick 43 relative to the frame portion 80 does not affect the operation of the transmission member 96. Furthermore, rotation of the transmission member 96 relative to the frame portion 80 does not affect the operation of the joystick 43. The outer bearing 81 supports the joystick 43 so that it can rotate relative to the transmission member 96.

The transmission member 96 is positioned so that it passes through the connecting portion 100. The transmission member 96 is positioned so that the other end of the transmission member 96 (the left end in Figure 7) abuts against the input portion 110. A 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 together by the bolt 97. A bolt 98 fits between the input portion 110 and the connecting portion 100, further strengthening the connection between the input portion 110 and the transmission member 96.

In the cross-sectional view shown in FIG. 7, the input unit 110 has an L-shape. The L-shaped input unit 110 has a first side extending in the vertical direction (vertical direction in FIG. 7) and a second side extending in the front-rear direction (X direction; horizontal direction in FIG. 7). The first side of the input unit 110 is connected to the transmission member 96 by a bolt 97. Two elongated holes 111, 112 are formed in the second side of the input unit 110. The elongated holes 111, 112 are formed so as to penetrate the plate-shaped input unit 110 in the thickness direction. Referring also to FIG. 8, the elongated holes 111, 112 extend in the front-rear direction (X direction). The elongated holes 111, 112 extend in a direction perpendicular to the left-right direction (Y direction), which is the direction in which the operator tilts the joystick 43.

The first lever portion 62 of the first electric lever 60 is disposed within the elongated hole 111. The second lever portion 67 of the second electric lever 65 is disposed within the elongated hole 112. The steering operation device 42 has two electric levers (the first electric lever 60 and the second electric lever 65). Two elongated holes 111, 112, the same number as the number of electric levers, are formed in the input portion 110. The lever portions of each electric lever are disposed within different elongated holes.

The first electric lever 60 and the second electric lever 65 are arranged side by side in the front-to-back direction (X direction), which is a direction 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 arranged side by side in this order in the front-to-back direction (X direction). The first electric lever 60 and the second electric lever 65 are arranged away from the joystick 43 in the front-to-back direction (X direction).

In the plan view from above shown in Figure 8, the long holes 111 and 112 have an elongated shape with their longitudinal direction in the front-to-back direction (X direction) and their lateral direction in the left-to-right direction (Y direction). The periphery of the long holes 111 and 112 shown in Figure 8 is a closed curve.

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).

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).

The periphery of the long holes 111, 112 does not necessarily have to be a closed curve. The long holes 111, 112 may be long, narrow gaps extending in the front-to-rear direction (X direction). The long hole 111 may extend to the edge of the input unit 110 and open to the edge of the input unit 110. The long hole 112 may extend to the edge of the input unit 110 and open to the edge of the input unit 110. The long holes 111 and 112 may be connected to each other.

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.

<Steering Operation of Wheel Loader 1>
The operation of changing the direction of travel of the traveling wheel loader 1 by operating the steering operation device 42 described above to change the body bending angle (FIG. 3) of the wheel loader 1 will be described below.

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

Meanwhile, the transmission member 96 rotates with the longitudinal direction (X direction) as its axis in accordance with 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 disposed within the elongated hole 111. The second lever unit 67 is disposed within 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 tilted relative to the first main body unit 61. The input unit 110 presses the second lever unit 67, thereby changing the angle at which the second lever unit 67 is inclined relative to the second main body unit 66.

The first electric lever 60 and the second electric lever 65 are mechanically input with both the tilt angle of the joystick 43 from its neutral position and the current vehicle body bending angle. Tilting the joystick 43 from its neutral position causes the first body portion 61 of the first electric lever 60 and the second body portion 66 of the second electric lever 65 to move left and right together 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. 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 in accordance with the current vehicle body bending angle, 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.

When the set angle of the front frame 11 relative to the rear frame 12 set by operating the joystick 43 differs from the current angle of the front frame 11 relative to the rear frame 12 fed back to the steering operation 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.

These electrical signals are input to a controller (not shown). In response to the input electrical signals, the controller generates a control signal that commands the angle of the front frame 11 relative to the rear frame 12. The controller outputs this control signal to the steering actuator 21, controlling 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.

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

From this state, when the operator tilts the joystick 43 to the right, the first body portion 61 of the first electric lever 60 and the second body portion 66 of the second electric lever 65 move integrally 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 the neutral state is 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 the neutral state is 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.

The controller receives electrical signals indicating these tilt angles and extends the left steering actuator 21 and contracts 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 and approaches the set angle of the front frame 11 relative to the rear frame 12.

The current vehicle body bending angle is fed back to the steering operation device 42 via a mechanical link 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.

Control is performed to adjust the amount of extension and contraction 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.

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 no longer tilts relative to the first main body portion 61, and the second lever portion 67 no longer tilts 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 a zero tilt angle, the controller stops the extension and contraction of the steering actuator 21 and maintains the amount of extension and contraction of the steering actuator 21 at that time. This stops the bending movement of the front frame 11 relative to the rear frame 12, and the vehicle body bending angle is maintained at the set angle.

Figure 9 is a view from the front of the steering operation device 42 with the joystick 43 in the neutral position. Figure 10 is a view from the front of the steering operation device 42 with the joystick 43 tilted to the left (YL direction). Figure 11 is a view from the front of the steering operation device 42 with the joystick 43 tilted to the right (YR direction).

The joystick 43 can be tilted left or right by the operator. The support part 50 is fixed to the left console 41 and does not move even when the joystick 43 is tilted. The joystick 43 moves relative to the support part 50. 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 joystick 43.

The knob wire 49 is electrically connected to the switch 45 (Figure 6) provided on the knob 44 at the tip of the joystick 43, and extends from the inside to the outside of the joystick 43. The knob wire 49 moves relative to the support 50 as the joystick 43 tilts left or right. The wire sleeve 79 houses the first lever wire 64 connected to the first body 61 of the first electric lever 60 and the second lever wire 69 connected to the second body 66 of the second electric lever 65. The first lever wire 64 moves relative to the support 50 as the first body 61 moves left or right. The second lever wire 69 moves relative to the support 50 as the second body 66 moves left or right.

The joystick 43, the first main body 61, and the second main body 66 are configured to operate as a single unit. The knob wire 49 connected to the joystick 43, the first lever wire 64 connected to the first main body 61, and the second lever wire 69 connected to the second main body 66 form the same movement system. As shown in Figures 9 to 11, the knob wire 49, the first lever wire 64, and the second lever wire 69 move in the same way.

The portions of the knob wire 49, first lever wire 64, and second lever wire 69 between the portion bound by the fixed clamp 58 and the portion bound by the movable clamp 78 move significantly left and right. Movement of other portions of the knob wire 49, first lever wire 64, and second lever wire 69 is relatively small. The movable space that needs to be secured for movement of the knob wire 49, first lever wire 64, and second lever wire 69 only needs to be large enough to accommodate movement of the portions between the portion bound by the fixed clamp 58 and the portion bound by the movable clamp 78. This makes it possible to reduce the movable space.

<Action and effect>
Although some of the description overlaps with the above description, the characteristic configuration and effects of the work machine of this embodiment can be summarized as follows.

As shown in Figures 5, 7 and 8, the steering operation device 42 includes a joystick 43 and a first electric lever 60. The joystick 43 accepts operation by the operator 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 main body portion 61 and a first lever portion 62 that can be tilted relative to the first main body portion 61. The first electric lever 60 outputs the tilt angle of the first lever portion 62 relative to the first main body portion 61. The joystick 43 and first main body portion 61 operate integrally.

If the joystick 43 and the first main body 61 move separately, two separate moving spaces are required for these separate movements, resulting in a large amount of moving space being required. By operating the joystick 43 and the first main body 61 as a single unit, it is possible to combine the moving spaces into one. Therefore, the moving space required for the steering operation device 42 can be reduced.

As shown in FIG. 6, the joystick 43 has a switch unit 45 that is operated by the operator's finger. As shown in FIGS. 5 to 7, the steering operation device 42 includes a knob wire 49 that is electrically connected to the switch unit 45 and extends from the inside to the outside of the joystick 43, and a first lever wire 64 that has one end connected to the first main body 61 of the first electric lever 60. By operating the joystick 43 and the first main body 61 together, the knob wire 49 and the first lever wire 64 can be made to function as the same movement system. As shown in FIGS. 9 to 11, the knob wire 49 and the first lever wire 64 can be made to move in the same way. Because the movement spaces required for the movement of the knob wire 49 and the first lever wire 64 can be combined into one, the movement space of the steering operation device 42 can be reduced.

As shown in Figures 5, 9-11, the steering operation device 42 includes a clamp that bundles the knob wire 49 and the first lever wire 64. Because the knob wire 49 and the first lever wire 64 are in the same motion system and move in the same way, it is possible to bundle both the knob wire 49 and the first lever wire 64 at the same clamp position. This simplifies the configuration of the steering operation device 42.

As shown in Figures 5, 7 to 11, the steering operation device 42 includes a support portion 50 that supports the joystick 43 so that it can move relatively. As shown in Figures 5, 9 to 11, the clamp that binds the knob wire 49 and the first lever wire 64 includes a fixed clamp 58 and a movable clamp 78. The fixed clamp 58 is fixed to the support portion 50. The movable clamp 78 moves relative to the support portion 50 together with the joystick 43 as the operator tilts the joystick 43.

The fixed clamp 58 bundles the knob wire 49 and the first lever wire 64 and secures them to the support part 50, while the movable clamp 78 bundles the knob wire 49 and the first lever wire 64 at a position separate from the fixed clamp 58. By bundling the knob wire 49 and the first lever wire 64 with clamps in two locations, the movable spaces of the knob wire 49 and the first lever wire 64 can be reliably combined into one.

As shown in Figures 5, 9-11, the movable clamp 78 bundles the knob wire 49 and the first lever wire 64 at a position along the path of the knob wire 49 that is closer to the joystick 43 than the fixed clamp 58. By positioning the fixed clamp 58 and the movable clamp 78 in this manner, the movable space for movement of the knob wire 49 and the first lever wire 64 is defined in the area between the movable clamp 78 and the fixed clamp 58. This clarifies the position of the movable space that needs to be secured.

As shown in FIG. 7 , the transmission member 96 mechanically transmits the current angle of the front frame 11 relative to the rear frame 12 to the steering operation device 42. The steering operation device 42 includes an input unit 110. The input unit 110 is connected to 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 unit 62 of the first electric lever 60. Operation of the joystick 43 by the operator is input to the first main body unit 61, and the movement of the vehicle body of the wheel loader 1 is fed back and input to the first lever unit 62. The first electric lever 60 can output the angle difference between the set value for the angle of the front frame 11 relative to the rear frame 12 and the current vehicle body bending angle. By appropriately controlling the steering actuator 21 based on this angle difference, the angle of the front frame 11 relative to the rear frame 12 can be easily adjusted to the set value.

As shown in Figures 5, 7-8, the steering operation device 42 has a first electric lever 60 and a second electric lever 65. The joystick 43, the first main body 61 of the first electric lever 60, and the second main body 66 of the second electric lever 65 operate integrally. Because the steering operation device 42 has multiple electric levers for redundancy, the reliability of the steering operation device 42 is improved. By operating the multiple main bodies of the multiple electric levers and the joystick 43 integrally, the moving space of the steering operation device 42 can be significantly reduced.

In the description of the above embodiment, a wheel loader 1 is given as an example of a work machine, but the invention can also be applied to other types of work machines, such as articulated dump trucks and motor graders.

<Additional Notes>
The above description includes the following additional features.

(Appendix 1)
a vehicle body frame having a rear frame and a front frame rotatably connected to the rear frame;
a steering actuator for changing the angle of the front frame relative to the rear frame;
a steering operation device that is operated by an operator to operate the steering actuator,
The steering operation device is
a joystick that accepts operator operations;
at least one electric lever having a main body and a lever that is tiltable relative to the main body, and that outputs a tilt angle of the lever relative to the main body;
A work machine in which the joystick and the main body operate integrally.

(Appendix 2)
The joystick has a switch portion that is operated by an operator's finger,
The work machine described in Appendix 1, wherein the steering operation device further includes a first electric wire electrically connected to the switch portion and extending from the inside to the outside of the joystick, and a second electric wire having one end connected to the main body portion.

(Appendix 3)
3. The work machine according to claim 2, wherein the steering operation device further includes a clamp that bundles the first electric wire and the second electric wire.

(Appendix 4)
the steering operation device further includes a support portion that supports the joystick so that the joystick can move relatively;
The work machine described in Appendix 3, wherein the clamp includes a movable clamp that moves relatively to the support part integrally with the joystick in response to an operation of tilting the joystick by an operator, and a fixed clamp that is fixed to the support part.

(Appendix 5)
The work machine according to claim 4, wherein the movable clamp bundles the first electric wire and the second electric wire together at a position in the path of the first electric wire that is closer to the joystick than the fixed clamp.

(Appendix 6)
a link that mechanically transmits a current angle of the front frame relative to the rear frame to the steering operation device,
The work machine according to any one of Supplementary Note 1 to Supplementary Note 5, wherein the steering operation device further includes an input unit connected to the link and inputting the current angle transmitted by the link to the lever unit.

(Appendix 7)
the at least one electric lever comprises a plurality of electric levers;
7. The work machine according to any one of claims 1 to 6, wherein the joystick and the main body portions of the electric levers operate integrally.

The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims, not the above description, and is intended to include all modifications that are equivalent in meaning to and within the scope of the claims.

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

Claims (7)

a vehicle body frame having a rear frame and a front frame rotatably connected to the rear frame;
a steering actuator for changing the angle of the front frame relative to the rear frame;
a steering operation device that is operated by an operator to operate the steering actuator,
The steering operation device is
a joystick that accepts operator operations;
at least one electric lever having a main body and a lever that is tiltable relative to the main body, and that outputs a tilt angle of the lever relative to the main body;
A work machine in which the joystick and the main body operate integrally. The joystick has a switch portion that is operated by an operator's finger,
2. The work machine according to claim 1, wherein the steering operation device further includes: a first electric wire electrically connected to the switch portion and extending from the inside to the outside of the joystick; and a second electric wire having one end connected to the main body portion. The work machine described in claim 2, wherein the steering operation device further includes a clamp that bundles the first electric wire and the second electric wire. the steering operation device further includes a support portion that supports the joystick so that the joystick can move relatively;
4. The work machine according to claim 3, wherein the clamp includes a movable clamp that moves integrally with the joystick relative to the support portion in response to an operation of tilting the joystick by an operator, and a fixed clamp that is fixed to the support portion. The work machine described in claim 4, wherein the movable clamp bundles the first electric wire and the second electric wire at a position in the path of the first electric wire that is closer to the joystick than the fixed clamp. a link that mechanically transmits a current angle of the front frame relative to the rear frame to the steering operation device,
6. The work machine according to claim 1, wherein the steering operation device further includes an input unit connected to the link and inputting the current angle transmitted by the link to the lever unit. the at least one electric lever comprises a plurality of electric levers;
The work machine according to claim 1 , wherein the joystick and the plurality of main body portions of the plurality of electric levers operate integrally.