Work machine, and method for controlling work machine

Abstract

To provide a work machine which can be easily and appropriately revolved by an operator.SOLUTION: A work machine includes a vehicle body, a steered road wheel, a first actuator, a second actuator, a steering angle sensor, a leaning angle sensor, and a controller. The steered road wheel is supported by the vehicle body. The first actuator changes a steering angle of the steered road wheel. The second actuator changes a leaning angle of the steered road wheel. The steering angle sensor outputs a first angle signal indicating the steering angle. The leaning angle sensor outputs a second angle signal indicating the leaning angle. The controller acquires the first angle signal and the second angle signal. The controller acquires the steering angle on the basis of the first angle signal. The controller acquires the leaning angle on the basis of the second angle signal. The controller acquires a target leaning angle in correspondence with the steering angle. The controller controls the second actuator so that the leaning angle becomes the target leaning angle.SELECTED DRAWING: Figure 7A

Description

Technical Field

[0001] The present invention relates to a working machine and a method for controlling the working machine.

Background Art

[0002] Some conventional working machines have a vehicle body, a steering wheel supported by the vehicle body, and a leaning mechanism (see Patent Document 1). In this type of working machine, the working machine can be turned by changing the steering angle of the steering wheel. Further, the turning radius of the working machine can be adjusted by changing the leaning angle of the steering wheel by the leaning mechanism.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above-described conventional working machine, when the working machine turns, the operator needs to operate both the steering lever for changing the steering angle and the leaning lever for changing the leaning angle at the same time. That is, the operation when the working machine turns is complicated for the operator. For this reason, if the operator cannot accurately operate both the steering lever and the leaning lever, there is a possibility that the operator cannot turn the working machine as desired.

[0005] An object of the present invention is to provide a working machine that can be easily and suitably turned by an operator.

Means for Solving the Problems

[0006] A working machine according to one aspect of the present invention includes a vehicle body, a steering wheel, a first actuator, a second actuator, a steering angle sensor, a leaning angle sensor, and a controller. The steering wheel is supported by the vehicle body. The first actuator changes the steering angle of the steering wheel. The second actuator changes the leaning angle of the steering wheel. The steering angle sensor outputs a first angle signal indicating the steering angle. The leaning angle sensor outputs a second angle signal indicating the leaning angle. The controller acquires the first angle signal and the second angle signal. The controller acquires the steering angle based on the first angle signal. The controller acquires the leaning angle based on the second angle signal. The controller acquires a target leaning angle corresponding to the steering angle. The controller controls the second actuator so that the leaning angle becomes the target leaning angle.

[0007] A method according to another aspect of the present invention is a method for controlling a working machine. The working machine includes a vehicle body, a steering wheel supported by the vehicle body, a first actuator that changes the steering angle of the steering wheel, a second actuator that changes the leaning angle of the steering wheel, a steering angle sensor that outputs a first angle signal indicating the steering angle, and a leaning angle sensor that outputs a second angle signal indicating the leaning angle.

[0008] The method according to this aspect includes acquiring the first angle signal and the second angle signal, acquiring the steering angle based on the first angle signal, acquiring the leaning angle based on the second angle signal, acquiring a target leaning angle corresponding to the steering angle, and controlling the second actuator so that the leaning angle becomes the target leaning angle.

Advantages of the Invention

[0009] According to the present invention, the second actuator is controlled so that the leaning angle of the steering wheel becomes the target leaning angle corresponding to the steering angle of the steering wheel. Thereby, the operator can automatically set the leaning angle only by changing the steering angle. Thereby, the operator can easily and suitably turn the working machine.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5A

Figure 5B

Figure 6A

Figure 6B

Figure 7A

Figure 7B

Figure 8A

Figure 8B

MODE FOR CARRYING OUT THE INVENTION

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view of a working machine 1 according to an embodiment. FIG. 2 is a side view of the working machine 1. As shown in FIG. 1, the working machine 1 includes a vehicle body 2, front wheels 3A and 3B, rear wheels 4A to 4D, and a working device 5. The vehicle body 2 includes a front frame 11, a rear frame 12, a cab 13, and a power chamber 14.

[0012] The rear frame 12 is connected to the front frame 11. The front frame 11 is coupled to the rear frame 12 so as to be rotatable with respect to the rear frame 12. For example, the front frame 11 can articulate left and right with respect to the rear frame 12.

[0013] In the following description, the front, rear, left, and right directions are defined in a state where the articulation angle of the front frame 11 with respect to the rear frame 12 is zero, that is, in a state where the front frame 11 and the rear frame 12 are straight, and the front, rear, left, and right directions of the vehicle body 2.

[0014] The cab 13 and the power unit compartment 14 are arranged on the rear frame 12. A driver's seat (not shown) is arranged in the cab 13. The power unit compartment 14 is arranged behind the cab 13. The front frame 11 extends forward from the rear frame 12. The front wheels 3A, 3B are attached to the front frame 11. The front wheels 3A, 3B are arranged apart in the left-right direction. The front wheels 3A, 3B are rotatably supported by the front frame 11. The rear wheels 4A - 4D are attached to the rear frame 12.

[0015] The working machine 5 is movably connected to the vehicle body 2. The working machine 5 includes a support member 15 and a blade 16. The support member 15 is movably connected to the vehicle body 2. The support member 15 supports the blade 16. The support member 15 includes a drawbar 17 and a circle 18. The drawbar 17 is arranged below the front frame 11.

[0016] The drawbar 17 is connected to the front portion 19 of the front frame 11. The drawbar 17 extends rearward from the front portion 19 of the front frame 11. The drawbar 17 is supported by the front frame 11 so as to be swingable at least in the vertical and horizontal directions of the vehicle body 2. For example, the front portion 19 includes a ball joint. The drawbar 17 is rotatably connected to the front frame 11 via the ball joint.

[0017] Circle 18 is connected to the rear part of the drawbar 17. Circle 18 is rotatably supported with respect to the drawbar 17. Blade 16 is connected to circle 18. Blade 16 is supported by drawbar 17 via circle 18. As shown in FIG. 2, blade 16 is rotatably supported by circle 18 around tilt axis 21. Tilt axis 21 extends in the left - right direction.

[0018] As shown in FIG. 2, the work machine 1 includes a plurality of steering actuators 41A, 41B for steering the front wheels 3A, 3B, and a plurality of articulation actuators 27, 28.

[0019] The plurality of steering actuators 41A, 41B are used to steer the front wheels 3A, 3B. For example, the plurality of steering actuators 41A, 41B are hydraulic cylinders. The plurality of steering actuators 41A, 41B are separately connected to the front wheels 3A, 3B. The plurality of steering actuators 41A, 41B expand and contract by hydraulic pressure. In the following description, the expansion and contraction of the plurality of steering actuators 41A, 41B, for example, the expansion and contraction of the hydraulic cylinders, is referred to as a "stroke operation".

[0020] The plurality of steering actuators 41A, 41B include a left steering cylinder 41A and a right steering cylinder 41B. The left steering cylinder 41A and the right steering cylinder 41B are arranged apart from each other in the left - right direction.

[0021] The left steering cylinder 41A is connected to the front frame 11 and the front wheel 3A. The right steering cylinder 41B is connected to the front frame 11 and the front wheel 3B. By the stroke operations of the left steering cylinder 41A and the right steering cylinder 41B, the front wheels 3A, 3B are steered.

[0022] In FIG. 2, the left steering actuator 41A is shown, while the right steering actuator 41B is not shown. Since the left steering actuator 41A and the right steering actuator 41B are paired members, in FIG. 2, the reference signs are shown in parentheses for the members not shown.

[0023] The plurality of articulated actuators 27, 28 are used to rotate the front frame 11 with respect to the rear frame 12. For example, the plurality of articulated actuators 27, 28 are hydraulic cylinders. The plurality of articulated actuators 27, 28 are connected to the front frame 11 and the rear frame 12. The plurality of articulated actuators 27, 28 expand and contract by hydraulic pressure.

[0024] The plurality of articulated actuators 27, 28 include a left articulated cylinder 27 and a right articulated cylinder 28. The left articulated cylinder 27 and the right articulated cylinder 28 are arranged apart from each other in the left-right direction.

[0025] The left articulated cylinder 27 is connected to the front frame 11 and the rear frame 12 on the left side of the vehicle body 2. The right articulated cylinder 28 is connected to the front frame 11 and the rear frame 12 on the right side of the vehicle body 2. By the stroke operations of the left articulated cylinder 27 and the right articulated cylinder 28, the front frame 11 rotates left and right with respect to the rear frame 12.

[0026] In FIG. 1, the right articulated cylinder 28 is shown, while the left articulated cylinder 27 is not shown. In FIG. 2, the left articulated cylinder 27 is shown, while the right articulated cylinder 28 is not shown. Since the left articulated cylinder 27 and the right articulated cylinder 28 are paired members, in FIGS. 1 and 2, the reference signs are shown in parentheses for the members not shown.

[0027] Figure 3 is a front view of the front part of the working machine 1. As shown in Figure 3, the working machine 1 is provided with a leaning mechanism 6. The leaning mechanism 6 tilts the front wheels 3A and 3B to the left and right. The leaning mechanism 6 includes an axle beam 56, a leaning rod 57, and a leaning actuator 61. The axle beam 56 extends horizontally from the front frame 11. The axle beam 56 is supported by the front frame 11 so as to be rotatable around a pivot shaft 58.

[0028] The axle beam 56 is connected to the front wheel 3A via a wheel bracket 59A. The axle beam 56 supports the front wheel 3A so as to be rotatable around a leaning shaft 54A. The axle beam 56 is connected to the front wheel 3B via a wheel bracket 59B. The axle beam 56 supports the front wheel 3B so as to be rotatable around a leaning shaft 54B. The leaning shafts 54A and 54B extend in the front-rear direction.

[0029] The leaning rod 57 extends horizontally through the front frame. The leaning rod 57 connects the front wheels 3A and 3B to each other. The leaning rod 57 is connected to the front wheel 3A via a wheel bracket 59A. The leaning rod 57 is connected to the front wheel 3B via a wheel bracket 59B.

[0030] The leaning actuator 61 is used to tilt the front wheels 3A and 3B. For example, the leaning actuator 61 is a hydraulic cylinder. The leaning actuator 61 is connected to the front frame 11 and the front wheels 3A and 3B. The leaning actuator 61 expands and contracts by hydraulic pressure. That is, by expanding and contracting the leaning actuator 61, the front wheels 3A and 3B rotate around the leaning shafts 54A and 54B. Thereby, the front wheels 3A and 3B tilt to the left and right.

[0031] As shown in FIG. 2, the working machine 1 includes a plurality of actuators 22-26 for changing the posture of the working implement 5. For example, the plurality of actuators 22-25 are hydraulic cylinders. The actuator 26 is a rotary actuator. In the present embodiment, the actuator 26 is a hydraulic motor. The actuator 26 may be an electric motor.

[0032] The plurality of actuators 22-25 are connected to the working implement 5. The plurality of actuators 22-25 expand and contract hydraulically. By expanding and contracting, the plurality of actuators 22-25 change the posture of the working implement 5 with respect to the vehicle body 2.

[0033] Specifically, the plurality of actuators 22-25 include a left lift cylinder 22, a right lift cylinder 23, a drawbar shift cylinder 24, and a blade tilt cylinder 25.

[0034] The left lift cylinder 22 and the right lift cylinder 23 are arranged apart from each other in the left-right direction. The left lift cylinder 22 and the right lift cylinder 23 are connected to the drawbar 17. The left lift cylinder 22 and the right lift cylinder 23 are connected to the front frame 11 via a lifter bracket 29. By the stroke operation of the left lift cylinder 22 and the right lift cylinder 23, the drawbar 17 swings up and down. Thereby, the blade 16 moves up and down.

[0035] The drawbar shift cylinder 24 is connected to the drawbar 17 and the front frame 11. The drawbar shift cylinder 24 is connected to the front frame 11 via a lifter bracket 29. The drawbar shift cylinder 24 extends obliquely downward from the front frame 11 toward the drawbar 17. By the stroke operation of the drawbar shift cylinder 24, the drawbar 17 swings left and right.

[0036] The blade tilt cylinder 25 is connected to the circle 18 and the blade 16. Due to the stroke operation of the blade tilt cylinder 25, the blade 16 rotates around the tilt axis 21.

[0037] The actuator 26 is connected to the drawbar 17 and the circle 18. The actuator 26 rotates the circle 18 relative to the drawbar 17. Thereby, the blade 16 rotates around the rotation axis extending in the vertical direction.

[0038] FIG. 4 is a schematic diagram showing the configuration of the working machine 1. As shown in FIG. 4, the working machine 1 includes a drive source 31 and a hydraulic pump 32. The working machine 1 includes a steering valve 42A, an articulation valve 42B, a leaning valve 42C, and a work implement valve 34. The working machine 1 includes a power transmission device 33.

[0039] The drive source 31 is, for example, an internal combustion engine. Alternatively, the drive source 31 may be an electric motor, or a hybrid of an internal combustion engine and an electric motor.

[0040] The hydraulic pump 32 is driven by the drive source 31 to discharge hydraulic oil. The hydraulic pump 32 supplies hydraulic oil to the steering valve 42A, the articulation valve 42B, and the work implement valve 34. Thereby, a plurality of steering actuators 41A, 41B, a plurality of articulation actuators 27, 28, and a plurality of actuators 22 - 26 operate. In FIG. 4, only one hydraulic pump 32 is shown, but a plurality of hydraulic pumps may be provided.

[0041] The steering valve 42A is connected to the hydraulic pump 32 and a plurality of steering actuators 41A, 41B via a hydraulic circuit. The steering valve 42A controls the flow rate of the hydraulic oil supplied from the hydraulic pump 32 to the plurality of steering actuators 41A, 41B. When the hydraulic oil of the hydraulic pump 32 is supplied to the steering valve 42A, the plurality of steering actuators 41A, 41B perform a stroke operation.

[0042] The articulation valve 42B is connected to the hydraulic pump 32 and a plurality of articulation actuators 27, 28 via a hydraulic circuit. The articulation valve 42B controls the flow rate of the hydraulic oil supplied from the hydraulic pump 32 to the plurality of articulation actuators 27, 28. When the hydraulic oil of the hydraulic pump 32 is supplied to the articulation valve 42B, the plurality of articulation actuators 27, 28 perform a stroke operation.

[0043] The leaning valve 42C is connected to the hydraulic pump 32 and the leaning actuator 61 via a hydraulic circuit. The leaning valve 42C controls the flow rate of the hydraulic oil supplied from the hydraulic pump 32 to the leaning actuator 61. When the hydraulic oil of the hydraulic pump 32 is supplied to the leaning valve 42C, the leaning actuator 61 performs a stroke operation.

[0044] The work implement valve 34 is connected to the hydraulic pump 32 and a plurality of actuators 22 - 26 via a hydraulic circuit. The work implement valve 34 includes a plurality of valves respectively connected to the plurality of actuators 22 - 26. The work implement valve 34 controls the flow rate of the hydraulic oil supplied from the hydraulic pump 32 to the plurality of actuators 22 - 26.

[0045] The power transmission device 33 transmits the driving force from the drive source 31 to the rear wheels 4A - 4D. The power transmission device 33 may include a torque converter and / or a plurality of transmission gears. Alternatively, the power transmission device 33 may be a transmission such as an HST (Hydraulic Static Transmission) or an HMT (Hydraulic Mechanical Transmission).

[0046] As shown in FIG. 4, the work machine 1 includes a steering member 45, an articulation lever 55, a leaning lever 63, a work implement operation member 35, a shift member 53, and an accelerator operation member 36.

[0047] The steering member 45 is operable by an operator to steer the front wheels 3A, 3B. The steering member 45 is a lever such as a joystick. Alternatively, the steering member 45 may be a member other than a lever. For example, the steering member 45 may be a steering wheel.

[0048] The steering member 45 is connected to an operation sensor 51. The operation sensor 51 is included in the work machine 1. The operation sensor 51 outputs a steering operation signal indicating the operation of the steering member 45 by the operator.

[0049] The articulation lever 55 is operable by an operator to rotate the front frame 11 with respect to the rear frame 12. The articulation lever 55 is a lever such as a joystick. Alternatively, the articulation lever 55 may be a member other than a lever. The articulation lever 55 is connected to an operation sensor 60. The operation sensor 60 is included in the work machine 1. The operation sensor 60 outputs an articulation operation signal indicating the operation of the articulation lever 55 by the operator.

[0050] The leaning lever 63 is operable by an operator to tilt the front wheels 3A, 3B. The leaning lever 63 is a lever such as a joystick. Alternatively, the leaning lever 63 may be a member other than a lever. The leaning lever 63 is connected to the operation sensor 52. The operation sensor 52 outputs a leaning operation signal indicating the operation of the leaning lever 63 by the operator.

[0051] The work implement operation member 35 is operable by an operator to change the posture of the work implement 5. The work implement operation member 35 includes, for example, a plurality of operation levers. Alternatively, the work implement operation member 35 may be other members such as a switch or a touch panel. The work implement operation member 35 outputs a signal indicating the operation of the work implement operation member 35 by the operator.

[0052] The shift member 53 is operable by an operator to switch between forward and reverse travel of the working machine 1. The shift member 53 includes, for example, a shift lever. Alternatively, the shift member 53 may be other members such as a switch or a touch panel. The shift member 53 outputs a signal indicating the operation of the shift member 53 by the operator.

[0053] The accelerator operation member 36 is operable by an operator to run the working machine 1. The accelerator operation member 36 includes, for example, an accelerator pedal. Alternatively, the accelerator operation member 36 may be other members such as a switch or a touch panel. The accelerator operation member 36 outputs a signal indicating the operation of the accelerator operation member 36 by the operator.

[0054] The working machine 1 is equipped with a steering angle sensor 40, an articulation angle sensor 30, and a leaning angle sensor 62. The steering angle sensor 40 is used to detect the steering angle θ1 of the front wheels 3A and 3B. The steering angle sensor 40 outputs a steering angle signal (first angle signal) indicating the steering angle θ1. The steering angle signal is, for example, the stroke amounts of a plurality of steering actuators 41A and 41B. Note that the steering angle sensor 40 may directly detect the steering angle θ1.

[0055] Here, the steering angle θ1 is defined as follows. FIGS. 5A and 5B are top views showing the front part of the working machine 1. In FIGS. 5A and 5B, the working machine 1 in a state where the articulation angle is 0 degrees, that is, the front frame 11 is not bent with respect to the rear frame 12, is shown.

[0056] As shown in FIG. 5A, the working machine 1 includes a first steering shaft 43A and a second steering shaft 43B. The first steering shaft 43A and the second steering shaft 43B are the rotation shafts of the front wheels 3A and 3B.

[0057] The first steering shaft 43A and the second steering shaft 43B are provided on the front frame 11. The first steering shaft 43A and the second steering shaft 43B extend in the vertical direction. The first steering shaft 43A and the second steering shaft 43B respectively and rotatably support the front wheels 3A and 3B.

[0058] The steering angle θ1 is the angle at which the front wheels 3A and 3B rotate with respect to the front frame 11 about the first steering shaft 43A and the second steering shaft 43B. For example, the steering angle θ1 is the rotation angle of the front wheels 3A and 3B with respect to the front-rear direction of the front frame 11.

[0059] Specifically, a center line L1 is defined on the front frame 11. The center line L1 is the center line of the front frame 11 extending in the front-rear direction of the front frame 11. The first center line L1 passes through an articulation axis 44, which will be described later, in a top view of the working machine 1. The steering angle θ1 is the rotation angle of the front wheels 3A and 3B with respect to the center line L1.

[0060] The steering angle θ1 changes from the neutral position to the left and right by the stroke operation of a plurality of steering actuators 41A and 41B. The steering angle θ1 in the neutral position is zero degrees. The front wheels 3A and 3B are arranged parallel to the first center line L1 of the front frame 11 in the neutral position. In FIG. 5A, 3A' and 3B' indicate the front wheels in a state where they are steered by the steering angle θ1 to the left from the neutral position. In FIG. 5B, 3A' and 3B' indicate the front wheels in a state where they are steered by the steering angle θ1 to the right from the neutral position.

[0061] The articulation angle sensor 30 is used to detect the articulation angle of the front frame 11 with respect to the rear frame 12. The articulation angle sensor 30 outputs an articulation angle signal indicating the articulation angle. The articulation angle signal is, for example, the stroke amount of the left articulation cylinder 27 and the right articulation cylinder 28. Note that the articulation angle sensor 30 may directly detect the articulation angle.

[0062] Here, the articulation angle is defined as follows. As shown in FIGS. 5A and 5B, the working machine 1 includes an articulation axis 44. The articulation axis 44 is provided on the front frame 11 and the rear frame 12. The articulation axis 44 extends in the vertical direction. The front frame 11 and the rear frame 12 are connected to each other so as to be rotatable around the articulation axis 44. The articulation angle is the angle at which the front frame 11 rotates with respect to the rear frame 12 around the articulation axis 44.

[0063] The leaning angle sensor 62 is used to detect the leaning angle θ2 of the front wheels 3A and 3B. The leaning angle sensor 62 outputs a leaning angle signal (second angle signal) indicating the leaning angle θ2. The leaning angle signal is, for example, the stroke amount of the leaning actuator 61. Note that the leaning angle sensor 62 may directly detect the leaning angle θ2.

[0064] Here, the leaning angle θ2 is defined as follows. As shown in FIGS. 6A and 6B, the leaning angle θ2 is the tilting angle in the left-right direction of the front wheels 3A and 3B when the vehicle body 2 is viewed from the front. For example, the leaning angle θ2 is the tilting angle at which the front wheels 3A and 3B tilt around the leaning axes 54A and 54B when the vehicle body 2 is viewed from the front. In the following description, the state where the front wheels 3A and 3B are upright with respect to the horizontal plane H1 (3A and 3B shown by solid lines) is referred to as the neutral state of the front wheels 3A and 3B. When the front wheels 3A and 3B are in the neutral state, the leaning angle θ2 is zero degrees.

[0065] In FIG. 6A, the front wheels 3A and 3B have changed by the leaning angle θ2 to the left from the neutral state (3A” and 3B” shown by dashed lines). In FIG. 6B, the front wheels 3A and 3B have changed by the leaning angle θ2 to the right from the neutral state (3A and 3B shown by solid lines) (3A” and 3B” shown by dashed lines).

[0066] As shown in FIG. 4, the work machine 1 includes a controller 37. The controller 37 includes a storage device 38 and a processor 39. The processor 39 is, for example, a CPU and executes a program for controlling the work machine 1. The storage device 38 includes memories such as a RAM and a ROM, and auxiliary storage devices such as an SSD or an HDD. The storage device 38 stores a program and data for controlling the work machine 1.

[0067] The controller 37 controls the power transmission device 33 in response to the operation of the shift member 53. Thereby, the traveling direction of the work machine 1 is switched between forward and reverse. Alternatively, the shift member 53 may be mechanically connected to the power transmission device 33. By mechanically transmitting the operation of the shift member 53 to the power transmission device 33, the forward and reverse gears of the power transmission device 33 may be switched.

[0068] The controller 37 controls the drive source 31 and the power transmission device 33 in response to the operation of the accelerator operation member 36. Thereby, the work machine 1 travels. Further, the controller 37 controls the hydraulic pump 32 and the work machine valve 34 in response to the operation of the work machine operation member 35. Thereby, the work machine 5 operates.

[0069] The controller 37 acquires the operation amount of the steering member 45 based on the steering operation signal from the operation sensor 51. The controller 37 controls the steering valve 42A in response to the steering operation signal, thereby expanding and contracting the plurality of steering actuators 41A, 41B. Thereby, the controller 37 changes the steering angle θ1 of the front wheels 3A, 3B. The controller 37 acquires the steering angle signal from the steering angle sensor 40. The controller 37 calculates the steering angle θ1 of the front wheels 3A, 3B based on the steering angle signal.

[0070] The controller 37 acquires the operation amount of the articulation lever 55 based on the articulation operation signal from the articulation lever 55. The controller 37 controls the articulation valve 42B. For example, the controller 37 controls the articulation valve 42B in response to the articulation operation signal, thereby expanding and contracting the left articulation cylinder 27 and the right articulation cylinder 28. Thereby, the controller 37 changes the articulation angle. The controller 37 acquires the articulation angle signal from the articulation angle sensor 30. The controller 37 calculates the articulation angle based on the articulation angle signal.

[0071] The controller 37 acquires the operation amount of the learning lever 63 based on the learning operation signal from the learning lever 63. The controller 37 controls the learning valve 42C. For example, the controller 37 controls the learning valve 42C according to the learning operation signal to expand and contract the learning actuator 61. Thereby, the controller 37 changes the learning angle θ2 according to the operation of the learning lever 63 by the operator. The controller 37 acquires a learning angle signal from the learning angle sensor 62. The controller 37 calculates the learning angle θ2 based on the learning angle signal.

[0072] The controller 37 executes automatic learning control for changing the learning angle θ2 according to the steering angle θ1. Hereinafter, the automatic learning control will be described. In the automatic learning control, the controller 37 controls the learning valve 42C according to the steering angle θ1 to expand and contract the learning actuator 61. Thereby, the controller 37 automatically changes the learning angle θ2 without depending on the operation of the learning lever 63. FIGS. 7A and 7B are flowcharts showing the process of the automatic learning control.

[0073] In step 101, the controller 37 acquires the current steering angle θ1. In step 102, the controller 37 acquires the traveling direction of the vehicle body 2. In step 103, the controller 37 determines whether the traveling direction of the vehicle body 2 is the forward direction.

[0074] Here, when the traveling direction of the vehicle body 2 is the forward direction (Yes in S103), in step 104, the controller 37 acquires the first table data as the target learning angle table data. The first table data is stored in the storage device 38.

[0075] The first table data is the steering angle θ1 of the front wheels 3A and 3B when the vehicle body 2 travels forward and the target learning angle θ T2It defines the relationship with. FIG. 8A is a diagram showing an example of first table data. As shown in FIG. 8A, in the first table data, when the leftward steering angle θ1 of the front wheels 3A, 3B is α1 or less, the target leaning angle θ T2 is 0. When the leftward steering angle θ1 of the front wheels 3A, 3B is greater than α1, as the steering angle θ1 increases, the leftward target leaning angle θ T2 increases.

[0076] When the rightward steering angle θ1 of the front wheels 3A, 3B is α2 or less, the target leaning angle θ T2 is 0. When the rightward steering angle θ1 of the front wheels 3A, 3B is greater than α2, as the steering angle θ1 increases, the rightward target leaning angle θ T2 increases.

[0077] When the traveling direction of the vehicle body 2 is not the forward direction (No in S104), that is, when the traveling direction of the vehicle body 2 is the backward direction, in step 106, the controller 37 acquires the second table data as the target leaning angle table data. The second table data is stored in the storage device 38.

[0078] The second table data defines the relationship between the steering angle θ1 of the front wheels 3A, 3B when the vehicle body 2 travels backward and the target leaning angle θ T2 FIG. 8B is a diagram showing an example of the second table data. As shown in FIG. 8B, in the second table data, when the leftward steering angle θ1 of the front wheels 3A, 3B is α1 or less, the target leaning angle θ T2 is 0. When the leftward steering angle θ1 of the front wheels 3A, 3B is greater than α1, as the steering angle θ1 increases, the rightward target leaning angle θ T2 increases.

[0079] When the rightward steering angle θ1 of the front wheels 3A, 3B is α2 or less, the target leaning angle θ T2 is 0. When the rightward steering angle θ1 of the front wheels 3A, 3B is greater than α2, as the steering angle θ1 increases, the leftward target leaning angle θ T2increases. In the first table data and the second table data, the steering angle θ1 and the target leaning angle θ T2 may be associated using a function. In this case, a function indicating the correspondence between the steering angle θ1 and the target leaning angle θ T2 is stored in the storage device 38.

[0080] In step 106, the controller 37 refers to the target leaning angle table data and acquires the target leaning angle θ T2 corresponding to the steering angle θ1 from the target leaning angle table data.

[0081] In step 107, the controller 37 controls the leaning actuator 61 so that the leaning angle θ2 becomes the target leaning angle θ T2 . In step 107, the controller 37 controls the leaning actuator 61 by executing the process shown in FIG. 8B.

[0082] In step 107A, the controller 37 acquires the current leaning angle θ2. In step 107B, the controller 37 calculates the error between the target leaning angle θ T2 and the current leaning angle θ2 (= θ T2 - θ2). In step 107C, the controller 37 acquires the speed table data.

[0083] The speed table data defines the relationship between the leaning angles θ2 of the front wheels 3A and 3B and the target leaning speed. In the speed table data, the greater the leaning angle θ2, the greater the target leaning speed. The speed table data is stored in the storage device 38. The correspondence between the leaning angle θ2 and the target leaning speed may be associated using a function. In this case, a function indicating the correspondence between the leaning angle θ2 and the target leaning speed is stored in the storage device 38.

[0084] In step 107D, the controller 37 refers to the speed table data and obtains the target leaning speed corresponding to the current leaning angle θ2 from the leaning speed table. In step 107E, the controller 37 operates the leaning actuator 61 at the target leaning speed until the above error becomes zero. When the above error becomes zero, the controller 37 ends the process of step 107.

[0085] As described above, when the vehicle body 2 is moving forward, the controller 37 refers to the first table data and determines the target leaning angle θ from the steering angle θ1. T2 Therefore, when the leftward steering angle θ1 is less than or equal to α1, and when the rightward steering angle θ1 is less than or equal to α2, the target leaning angle θ T2 is 0. Therefore, the controller 37 maintains the front wheels 3A, 3B in a neutral state. Alternatively, the controller 37 may maintain the previous leaning angle θ2 according to the operator's operation.

[0086] When the leftward steering angle θ1 is greater than α1, the controller 37 controls the leaning actuator 61 so that the leaning angle θ2 becomes the leftward target leaning angle θ T2 that increases as the steering angle θ1 increases. Thereby, as shown in FIG. 5A, when the front wheels 3A, 3B are steered to the left, the leaning actuator 61 is controlled so that the front wheels 3A, 3B lean to the left as shown in FIG. 6A.

[0087] When the rightward steering angle θ1 is greater than α2, the controller 37 controls the leaning actuator 61 so that the leaning angle θ2 becomes the rightward target leaning angle θ T2 that increases as the steering angle θ1 increases. Thereby, as shown in FIG. 5B, when the front wheels 3A, 3B are steered to the right, the leaning actuator 61 is controlled so that the front wheels 3A, 3B lean to the right as shown in FIG. 6B.

[0088] When the vehicle body 2 is moving backward, the controller 37 refers to the second table data to determine the target leaning angle θ from the steering angle θ1. Therefore, when the leftward steering angle θ1 is equal to or less than α1 and when the rightward steering angle θ1 is equal to or less than α2, the target leaning angle θ T2 is 0, similar to when the vehicle body 2 is moving forward. T2

[0089] When the leftward steering angle θ1 is greater than α1, the controller 37 controls the leaning actuator 61 so that the leaning angle θ2 becomes the rightward target leaning angle θ T2 that increases as the steering angle θ1 increases. When the rightward steering angle θ1 is greater than α2, the controller 37 controls the leaning actuator 61 so that the leaning angle θ2 becomes the leftward target leaning angle θ T2 that increases as the steering angle θ1 increases. Therefore, the tilting direction of the front wheels 3A and 3B during backward movement is opposite to that during forward movement.

[0090] In the working machine 1 according to the present embodiment described above, the controller 37 acquires the steering angle θ1 based on the steering angle signal. The controller 37 acquires the leaning angle θ2 based on the leaning angle signal. The controller 37 acquires the target leaning angle θ T2 corresponding to the steering angle θ1. The controller 37 controls the leaning actuator 61 so that the leaning angle θ2 becomes the target leaning angle θ T2 . Thereby, the leaning angle θ2 is changed according to the steering angle θ1.

[0091] For this reason, the operator can automatically set the leaning angle θ2 corresponding to the steering angle θ1 only by operating the first steering member 45 and / or the second steering member 46, without operating the leaning lever 63. That is, the operator can easily and suitably turn the working machine 1.

[0092] ​Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the gist of the invention.

[0093] When the front frame 11 is rotated with respect to the rear frame 12, the leaning angle θ2 may be changed according to the steering angle θ1. For example, when the articulation angle is "θ3", the difference between the steering angle θ1 and the articulation angle θ3 (= θ1 - θ3), and the target leaning angle θ T2 Table data showing the correspondence with is used.

[0094] In this case, by replacing the steering angle θ1 on the horizontal axis in FIGS. 7A and 7B with the difference between the steering angle θ1 and the articulation angle θ3 (= θ1 - θ3), the leaning angle θ2 is set to the target leaning angle θ in the same processing mode as in the above embodiment. T2 can be automatically set to.

[0095] It may be possible to switch between enabling and disabling the automatic leaning control. The controller 37 acquires the current roll angle of the vehicle body 2, and may enable the automatic leaning control when the roll angle is equal to or less than a predetermined roll angle, and disable the automatic leaning control when the roll angle is greater than the predetermined roll angle.

Industrial Applicability

[0096] According to the present invention, the operator can automatically set the leaning angle simply by changing the steering angle. That is, the operator can easily and suitably turn the work machine.

Explanation of Reference Numerals

[0097] 1 Work machine 2 Vehicle body 3A, 3B Front wheels 11 Front frame 12 Rear frame 37 Controller 40 Steering angle sensor 41 Steering actuator 61 Leaning actuator 62 Leaning angle sensor θ1 Steering angle θ2 Leaning angle θ T2 Target leaning angle

Claims

1. A vehicle body, a steering wheel supported by the vehicle body, a first actuator for changing the steering angle of the steering wheel, a second actuator for changing the leaning angle of the steering wheel, a steering angle sensor that outputs a first angle signal indicating the steering angle, a leaning angle sensor that outputs a second angle signal indicating the leaning angle, a controller that acquires the first angle signal and the second angle signal, and comprising, the controller, acquires the steering angle based on the first angle signal, acquires the leaning angle based on the second angle signal, acquires a target leaning angle corresponding to the steering angle, controls the second actuator so that the leaning angle becomes the target leaning angle, when the steering angle is less than a predetermined angle, the target leaning angle is zero, when the steering angle is greater than the predetermined angle, the greater the steering angle, the greater the target leaning angle, a working machine.

2. The target leaning angle includes a first target leaning angle when the steering angle is less than or equal to the predetermined angle and a second target leaning angle when the steering angle is greater than the predetermined angle, the controller, when the steering angle is less than the predetermined angle, controls the second actuator so that the leaning angle becomes the first target leaning angle, when the steering angle is greater than the predetermined angle, controls the second actuator so that the leaning angle becomes the second target leaning angle, The working machine according to Claim 1.

3. As the steering angle increases, the second target leaning angle increases, The working machine according to Claim 2.

4. the controller, acquires the target leaning angle corresponding to the steering angle based on table data indicating the correspondence between the steering angle and the target leaning angle, The working machine according to any one of Claims 1 to 3.

5. A vehicle body, a steering wheel supported by the vehicle body, a first actuator for changing the steering angle of the steering wheel, a second actuator for changing the leaning angle of the steering wheel, a steering angle sensor that outputs a first angle signal indicating the steering angle, a leaning angle sensor that outputs a second angle signal indicating the leaning angle, a controller that acquires the first angle signal and the second angle signal, and comprising, the controller, acquires the steering angle based on the first angle signal, Obtain the leaning angle based on the second angle signal, Obtain the target leaning angle corresponding to the steering angle, Control the second actuator so that the leaning angle becomes the target leaning angle, Control the second actuator so that the tilting direction of the steering wheel during reverse travel is opposite to the tilting direction of the steering wheel during forward travel, Work machine.

6. A method for controlling a work machine including a vehicle body, a steering wheel supported by the vehicle body, a first actuator for changing the steering angle of the steering wheel, a second actuator for changing the leaning angle of the steering wheel, a steering angle sensor for outputting a first angle signal indicating the steering angle, and a leaning angle sensor for outputting a second angle signal indicating the leaning angle, comprising: Obtaining the first angle signal and the second angle signal, Obtaining the steering angle based on the first angle signal, Obtaining the leaning angle based on the second angle signal, Obtaining the target leaning angle corresponding to the steering angle, Controlling the second actuator so that the leaning angle becomes the target leaning angle, Comprising, When the steering angle is smaller than a predetermined angle, the target leaning angle is zero, When the steering angle is larger than the predetermined angle, the larger the steering angle, the larger the target leaning angle, Method.

7. The target leaning angle includes a first target leaning angle when the steering angle is less than or equal to the predetermined angle and a second target leaning angle when the steering angle is greater than the predetermined angle, When the steering angle is smaller than the predetermined angle, controlling the second actuator so that the leaning angle becomes the first target leaning angle, When the steering angle is larger than the predetermined angle, controlling the second actuator so that the leaning angle becomes the second target leaning angle, The method according to claim 6, further comprising.

8. Increasing the second target leaning angle as the steering angle increases, The method according to claim 7, further comprising.

9. Obtaining the target leaning angle corresponding to the steering angle based on table data indicating the correspondence between the steering angle and the target leaning angle, The method according to any one of claims 6 to 8, further comprising.

10. A method for controlling a working machine including a vehicle body, a steering wheel supported by the vehicle body, a first actuator for changing the steering angle of the steering wheel, a second actuator for changing the leaning angle of the steering wheel, a steering angle sensor for outputting a first angle signal indicating the steering angle, and a leaning angle sensor for outputting a second angle signal indicating the leaning angle, comprising: acquiring the first angle signal and the second angle signal; acquiring the steering angle based on the first angle signal; acquiring the leaning angle based on the second angle signal; acquiring a target leaning angle corresponding to the steering angle; controlling the second actuator so that the leaning angle becomes the target leaning angle; controlling the second actuator so that the tilting direction of the steering wheel during reverse travel is opposite to the tilting direction of the steering wheel during forward travel; A method comprising the above.

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