Work vehicles

Abstract

The present invention provides a work vehicle that can appropriately determine whether or not to apply the brakes to one side and can appropriately apply the brakes to one side. [Solution] The work vehicle 1 comprises a running body 11, a power unit 31 having electric motors 34 that drive each wheel 22 provided on the left and right sides of the running body 11, a brake operating device 52, a single brake indicator 57, a steering device 41 that steers the running body 11 based on the operation of a steering operating device 42, and a running control unit 101a. When the single brake indicator 57 is operated, the running control unit 101a controls the electric motor 34 corresponding to the inner wheel to suppress the rotation speed of the inner wheel located in the steering direction of the steering operating device 42, based on whether or not the brake operating device 52 is being operated.

Description

Technical Field

[0001] The present invention relates to a work vehicle such as an electric tractor in which wheels are driven by an electric motor.

Background Art

[0002] Patent Document 1 discloses a drive system for a tractor that detects the operating states of a right brake pedal and a left brake pedal in a work vehicle equipped with a two-piece brake pedal for independently braking the left and right wheels on both sides, and controls the activation and deactivation of all-wheel drive and differential lock.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The drive system of the tractor in Patent Document 1 is configured to drive the wheels by a drive source using an internal combustion engine (engine), and is not configured to drive the wheels by an electric motor. Therefore, it is not possible to control the rotational speeds of the electric motors of the left and right wheels appropriately in response to a braking operation by the user. In the drive system of Patent Document 1, since it is a two-piece brake pedal, when the two-piece brake pedal is changed to a single brake pedal, it is not possible to determine the execution or non-execution of a single brake, and it is not possible to appropriately execute a single brake.

[0005] The present invention has been made to solve such problems of the prior art, and an object thereof is to provide a work vehicle that can appropriately determine the execution or non-execution of a single brake and can appropriately execute a single brake.

Means for Solving the Problems

[0006] A work vehicle according to one aspect of the present invention comprises a vehicle body, a power unit having electric motors for driving each wheel provided on the left and right sides of the vehicle body, a brake operating device, a single brake indicator, a steering device for steering the vehicle body based on the operation of a steering operating device, and a driving control unit, wherein when the single brake indicator is operated, the driving control unit controls the electric motor corresponding to the inner wheel to suppress the rotational speed of the inner wheel located in the steering direction of the steering operating device, based on whether or not the brake operating device is being operated.

[0007] A work vehicle according to another aspect of the present invention comprises a vehicle body, a power unit having electric motors for driving each wheel provided on the left and right sides of the vehicle body, a steering device for steering the vehicle body based on the operation of a steering control device, an input unit for receiving an operation input to suppress the rotation speed of an inner wheel located in the steering direction of the steering control device, and a driving control unit, wherein the driving control unit controls the electric motor corresponding to the inner wheel to suppress the rotation speed of the inner wheel when an operation input is received from the input unit while braking force is applied to both wheels by brake operation. [Effects of the Invention]

[0008] According to the above-mentioned work vehicle, it is possible to appropriately determine whether or not to apply the brakes to one side, and to apply the brakes to one side appropriately. [Brief explanation of the drawing]

[0009] [Figure 1] This is a diagram illustrating an example of a work vehicle system. [Figure 2] This figure shows an example of equipment and devices related to propulsion using a traction device. [Figure 3] This is a schematic side view showing an example of a work vehicle. [Figure 4] This is a schematic plan view showing an example of a work vehicle. [Figure 5] This is a schematic side view showing another example of a work vehicle. [Figure 6] This is a diagram showing the area around the driver's seat. [Figure 7] It is a perspective view of the lifting device seen from the rear. [Figure 8] It is a diagram showing another example of devices and equipment related to the traveling by the traveling device. [Figure 9A] It is a diagram showing the traveling control unit of the work vehicle and peripheral devices, etc. [Figure 9B] It is a diagram showing that the traveling control unit controls the electric motor and the braking mechanism. [Figure 10A] It is a flowchart showing the first example of the traveling control process by the traveling control unit. [Figure 10B] It is a flowchart showing the second example of the traveling control process by the traveling control unit. [Figure 10C] It is a flowchart showing the third example of the traveling control process by the traveling control unit. [Figure 10D] It is a flowchart showing the fourth example of the traveling control process by the traveling control unit. [Figure 10E] It is a flowchart showing the fifth example of the traveling control process by the traveling control unit. [Figure 10F] It is a flowchart showing the sixth example of the traveling control process by the traveling control unit. [Figure 10G] It is a flowchart showing the seventh example of the traveling control process by the traveling control unit. [Figure 10H] It is a flowchart showing the eighth example of the traveling control process by the traveling control unit. [Figure 10I] It is a flowchart showing the ninth example of the traveling control process by the traveling control unit. [Figure 10J] It is a flowchart showing the tenth example of the traveling control process by the traveling control unit. [Figure 10K] It is a flowchart showing the eleventh example of the traveling control process by the traveling control unit. [Figure 11] It is a diagram showing the first determination table. [Figure 12] It is a diagram showing the second determination table. [Figure 13] It is a diagram showing the third determination table. [Figure 14]It is a diagram showing the 4th determination table. [Figure 15] It is a diagram showing the 5th determination table. [Figure 16] It is a diagram showing the 6th determination table. [Figure 17] It is a schematic plan view explaining the rear wheel disc brake and the front wheel disc brake. [Figure 18] It is a diagram showing the 7th determination table.

Embodiments for Carrying Out the Invention

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram explaining an example of the system of the work vehicle 1. FIG. 2 is a diagram showing an example of devices and equipment related to traveling by the traveling device 21. FIG. 3 is a schematic side view showing an example of the work vehicle 1, and FIG. 4 is a schematic plan view showing an example of the work vehicle 1. The work vehicle 1 is a vehicle that can travel by the traveling device 21. In the present embodiment, the work vehicle 1 is a tractor capable of mounting the work device 2 (implement) on the traveling vehicle body 11 (airframe). Hereinafter, the work vehicle 1 will be described mainly with respect to a tractor that operates by manual operation by an operator seated in the driver's seat 12.

[0011] Although detailed description is omitted, the work vehicle 1 may operate by automatic driving control not based on the manual operation of the operator, or by remote driving control by manual operation with a remote operation device at a remote location. Further, the work vehicle 1 only needs to be a vehicle that can travel by the traveling device 21 and can attach and detach the work device 2, and is not limited to a tractor. For example, the work vehicle 1 may be a construction work machine such as a compact track loader or a backhoe that can attach and detach a work device (attachment).

[0012] Also, in the following description, the direction in which the operator seated in the driver's seat 12 of the work vehicle 1 faces (FIG 3. The left side of Figure 4 is called the front, and the opposite direction (right side of Figures 3 and 4) is called the rear. The left side of the worker (the front side in Figure 3, the bottom side in Figure 4) is called the left, and the right side of the worker (the back side in Figure 3, the top side in Figure 4) is called the right. The horizontal direction, which is perpendicular to the front-back direction, is called the width direction. And the direction perpendicular to the horizontal direction is called the up-down direction.

[0013] As shown in Figures 3 and 4, the work vehicle 1 comprises a vehicle body 11 and a running gear 21. The vehicle body 11 supports various devices and equipment provided by the work vehicle 1. For example, the vehicle body 11 is provided with a driver's seat 12 and a protective mechanism 13 for protecting the driver's seat 12. The protective mechanism 13 is, for example, a cabin 13A that surrounds the driver's seat 12. The protective mechanism 13 is not limited to a cabin 13A, and may be a canopy or a rope erected behind the driver's seat 12.

[0014] The running gear 21 is a device that supports the vehicle body 11 so that it can move. The running gear 21 provides propulsion to the vehicle body 11 by being driven. The running gear 21 has one or more wheels 22 that rotate by power supplied from the power unit 31. In this embodiment, the running gear 21 has a plurality of wheels 22, and these plurality of wheels 22 are spaced apart in the longitudinal direction or in the width direction. The running gear 21 has a pair of front wheels 22F that support the front side of the vehicle body 11, and a pair of rear wheels 22R that support the rear side of the vehicle body 11. In the example shown in Figures 3 and 4, the outer diameter of the rear wheels 22R is larger than the outer diameter of the front wheels 22F, but it may be set to be approximately the same as the outer diameter of the front wheels 22F.

[0015] Specifically, the left front wheel 22F1 and the right front wheel 22F2 are spaced apart in the width direction of the vehicle body 11. The left rear wheel 22R1 and the right rear wheel 22R2 are spaced apart in the width direction of the vehicle body 11. Furthermore, the left front wheel 22F1 and the left rear wheel 22R1 are spaced apart in the longitudinal direction of the vehicle body 11. And the right front wheel 22F2 and the right rear wheel 22R2 are spaced apart in the longitudinal direction of the vehicle body 11.

[0016] In the examples shown in Figures 3 and 4, the multiple wheels 22 of the running gear 21 are wheeled wheels 22A, each consisting of a tire 23. The wheeled wheel 22A includes a tire 23, an annular rim 24 on which the tire 23 is fitted around the outer circumference, and a hub 25 located in the center of the tire 23 and to which the rim 24 is attached to the axle.

[0017] Note that the multiple wheels 22 are not limited to wheeled wheels 22A, but may also be crawler-type wheels 22B (endless tracks), as shown in Figure 5. Figure 5 is a schematic side view showing another example of the work vehicle 1. The crawler-type wheel 22B has a crawler 26, a drive wheel 27 that circulates the crawler 26, and a driven wheel 28 that rotates in conjunction with the circulating drive of the crawler 26. The crawler 26 is, for example, a rubber crawler made of an elastic material such as rubber. In addition to the crawler 26, drive wheel 27, and driven wheel 28, the crawler-type wheel 22B may also include multiple idler wheels 29.

[0018] Furthermore, while it is preferable that at least one pair of wheels 22 in the width direction have a similar configuration among the multiple wheels 22, the front wheels 22F and rear wheels 22R may have different configurations. That is, as shown in the modified example in Figure 5, the front wheels 22F may be wheeled wheels 22A and the rear wheels 22R may be crawler-type wheels 22B, or all of the multiple wheels 22 may be crawler-type wheels 22B. Also, the running gear 21 may not have both the front wheels 22F and the rear wheels 22R, i.e., a total of four wheels 22, but may have only one pair in the width direction, i.e., a total of two crawler-type wheels 22B. The following explanation will focus on the case where all of the multiple wheels 22 are wheeled wheels 22A, as shown in Figures 3 and 4.

[0019] The power unit 31 is a device that supplies power to the running gear 21. As shown in Figure 1, the power unit 31 includes, for example, one or more electric motors 34, and drives the running gear 21 with the power (rotational driving force) generated by the one or more electric motors 34. In other words, the work vehicle 1 is an electric work vehicle driven by electric motors 34. The electric motors 34 are permanent magnet embedded type AC synchronous motors or wound field type synchronous motors, etc. The electric motors 34 are driven by power supplied from a first battery 111 (main battery) provided in the running body 11. The first battery 111 is a rechargeable secondary battery such as a lithium-ion battery or a lead-acid battery. The first battery 111 has multiple cells inside, and the multiple cells are electrically connected in series and parallel. A PDU 73 and multiple (four in this case) inverters 74 are provided in the power supply path connecting the first battery 111 and the electric motors 34. The PDU 73 is a Power Distribution Unit that distributes power from the first battery 111 and supplies it to four inverters 74. The inverters 74 are devices that drive the electric motors 34, converting DC power into three-phase AC power and supplying this three-phase AC power to the electric motors 34. The inverters 74 can arbitrarily change the current and voltage of the power supplied to the electric motors 34.

[0020] In this embodiment, the power unit 31 includes a plurality of electric motors 34 that supply power to each wheel 22 of the running gear 21. In other words, the power unit 31 has a plurality of electric motors 34 corresponding to each wheel 22, and each wheel 22 is driven independently by the corresponding electric motor 34. The plurality of electric motors 34 include a first electric motor 34a that drives the left front wheel 22F1, a second electric motor 34b that drives the right front wheel 22F2, a third electric motor 34c that drives the left rear wheel 22R1, and a fourth electric motor 34d that drives the right rear wheel 22R2. At least the first electric motors 34a to the fourth electric motors 34d are capable of forward and reverse rotation.

[0021] The power unit 31 may also supply power to a device other than the traveling device 21. In this embodiment, the power unit 31 includes, in addition to a plurality of electric motors 34 that drive the traveling device 21, a fifth electric motor 34e for driving the PTO shaft 36 that supplies power to the work device 2, and a sixth electric motor 34f for driving the hydraulic pump that operates the hydraulic equipment provided on the work vehicle 1. In this embodiment, the PTO shaft 36 is provided projecting rearward from the rear of the traveling vehicle body 11. The PTO shaft 36 may also be provided projecting forward from the front of the traveling vehicle body 11, and the PTO shaft 36 is provided on at least one of the front and rear of the traveling vehicle body 11.

[0022] The following description of the work vehicle 1 will be based on the example where the power unit 31 includes multiple electric motors 34 that supply power to each of the wheels 22. However, the power unit 31 may also include a common electric motor 34 that supplies power to the multiple wheels 22. In such a case, the multiple wheels 22 are driven by the power supplied from the common electric motor 34. Furthermore, the electric motor 34 may also supply power to other devices (PTO shaft 36, hydraulic pump, etc.) in addition to the multiple wheels 22, and the number of electric motors 34 in the power unit 31 and the destinations of the power supply (each wheel 22, PTO shaft 36, etc.) are not limited to the example described above.

[0023] The output shaft of the electric motor 34 is directly or indirectly connected to the input shaft of the power supply destination, and transmits the generated power to the destination. The output shaft of the electric motor 34 is indirectly connected to the input shaft of the power supply destination, for example, via a transmission 35 that includes multiple gears.

[0024] As shown in Figures 1 and 2, the work vehicle 1 is equipped with a steering device 41. The steering device 41 is a device that changes the steering direction and steering angle (rudder angle) of the work vehicle 1. The steering device 41 includes a steering control tool 42, a steering shaft 43, a steering control valve 44, a steering cylinder 45, an arm 46 (knuckle arm), and a steering angle detection device 47.

[0025] The steering control device 42 has a steering handle 42a (steering wheel). The steering handle 42a is located around the driver's seat 12 and is operated by an operator seated in the driver's seat 12.

[0026] The steering shaft 43 is a pivot that rotatably supports the steering wheel 42a.

[0027] The steering control valve 44 is supplied with hydraulic fluid discharged by the hydraulic pump and adjusts the hydraulic fluid supplied to the steering cylinder 45. The steering control valve 44 is a three-position control valve that can be switched by, for example, the movement of a spool, and switches according to the steering direction (rotation direction) of the steering shaft 43.

[0028] The steering cylinder 45 is driven by hydraulic fluid supplied from the steering control valve 44. The steering cylinder 45 expands or contracts in one or the other widthwise direction depending on the switching position and opening degree of the steering control valve 44.

[0029] The arm 46 is connected to the steering cylinder 45 and moves in accordance with the extension and retraction of the steering cylinder 45, thereby changing the steering (steering direction and steering angle) of the front wheel 22F.

[0030] The steering angle detection device 47 detects the steering operation (steering direction and steering angle) performed by the steering control device 42 and outputs a detection signal indicating the steering operation value to the control device 101. The steering angle detection device 47 is, for example, a steering angle sensor such as a rotary encoder.

[0031] The steering device 41 described above is merely an example and is not limited to the configuration described above. For example, as in this embodiment, if each electric motor 34 is driven independently, the running device 21 can make one thrust force in the width direction different from the other, thereby changing the steering angle. In such a configuration, the running device 21 may also serve as a part of the steering device 41. In such a case, the power unit 31 changes the driving force of the electric motor 34 according to the rotation angle of the steering wheel 42a (steering shaft 43), making one thrust force in the width direction different from the other, and changing the steering angle.

[0032] As shown in Figures 1 and 2, the work vehicle 1 is equipped with a braking device 51. The braking device 51 can brake the running gear 21. In this embodiment, the braking device 51 can brake the left rear wheel 22R1 and the right rear wheel 22R2. The braking device 51 includes a brake operating tool 52 and a braking mechanism 53.

[0033] Figure 6 shows the area around the driver's seat 12. As shown in Figure 6, the brake control device 52 is provided around the driver's seat 12 and is operated by the operator seated in the driver's seat 12. The brake control device 52 can be exemplified by a pedal (foot pedal), lever, button, switch, dial, or other control device. In this embodiment, the brake control device 52 is a single brake pedal 52a that controls the braking of the left rear wheel 22R1 and the right rear wheel 22R2. In other words, by operating a single brake pedal 52a, the left rear wheel 22R1 and the right rear wheel 22R2 are braked simultaneously.

[0034] Furthermore, as shown in Figure 1, the braking system 51 has a parking brake 56 (brake lever) that operates the braking of the left rear wheel 22R1 and the right rear wheel 22R2. As shown in Figure 6, the parking brake 56 is located around the driver's seat 12 and is operated by an operator seated in the driver's seat 12.

[0035] The braking mechanism 53 is, for example, a disc-type hydraulic brake. The braking mechanism 53 includes a first braking mechanism 53a capable of braking the left rear wheel 22R1 and a second braking mechanism 53b capable of braking the right rear wheel 22R2. The first braking mechanism 53a is provided on the axle of the left rear wheel 22R1. The second braking mechanism 53b is provided on the axle of the right rear wheel 22R2.

[0036] When the brake pedal 52a is pressed down (for example, from the release side to the braking side), the first braking mechanism 53a increases the braking force of the left rear wheel 22R1 and the second braking mechanism 53b increases the braking force of the right rear wheel 22R2, in proportion to the amount of operation. On the other hand, when the brake pedal 52a is released (for example, from the braking side back to the release side), the first braking mechanism 53a decreases the braking force of the left rear wheel 22R1 and the second braking mechanism 53b decreases the braking force of the right rear wheel 22R2, in proportion to the amount of operation.

[0037] When the parking brake 56 is operated from the release position to the braking position, the first braking mechanism 53a and the second braking mechanism 53b increase the braking force. On the other hand, when the parking brake 56 is operated from the braking position to the release position, the braking mechanism 53 decreases the braking force.

[0038] Furthermore, the braking device 51 is not limited to the example described above, and may also brake the left front wheel 22F1 and the right front wheel 22F2 in addition to the left rear wheel 22R1 and the right rear wheel 22R2.

[0039] As shown in Figure 1, the work vehicle 1 has a single-brake indicator 57 that instructs the application of single-brake braking. The single-brake indicator 57 only instructs the application of single-brake braking, and does not specify whether to apply the left or right brake.

[0040] As shown in Figure 6, the single brake indicator 57 is positioned in the center of the steering wheel 42a. The operator seated in the driver's seat 12 can operate the single brake indicator 57 while operating the steering wheel 42a. Note that the single brake indicator 57 is not limited to the steering wheel 42a; it may also be positioned in any location within the range of operation for the operator seated in the driver's seat 12.

[0041] The single-brake indicator 57 is, for example, a momentary operation switch, which is ON only while pressed and outputs a single-brake ON signal to the control device 101. When not pressed, the single-brake indicator 57 returns to the OFF state and does not output a single-brake ON signal to the control device 101 (it may output a single-brake OFF signal). The single-brake indicator 57 may also be an alternate operation switch. In addition to a switch, the single-brake indicator 57 may also be a pedal (foot pedal), lever, button, dial, etc.

[0042] As shown in Figure 1, the work vehicle 1 is equipped with an input unit 57A that receives input for controlling the rotation speed of the inner wheel located in the steering direction using the steering control device 42. Examples of the input unit 57A include a single brake indicator 57 and an operation icon that is displayed on the display device 103 and accepts touch operation. The operation icon is, for example, an icon indicating a single brake button. In the case of an operation icon, the display device 103 (input interface E) outputs a single brake ON signal to the control device 101 when the user touches the operation icon, and does not output a single brake ON signal to the control device 101 when the user does not touch the icon (it may output a single brake OFF signal).

[0043] As shown in Figures 3 and 4, the coupling device 61 can connect the work device 2 to the vehicle body 11. The work device 2 can be detachably attached to the coupling device 61. The coupling device 61 is provided at the front and / or rear of the vehicle body 11, and connects the work device 2 to the vehicle body 11. They can be coupled together. In this embodiment, the coupling device 61 is provided at both the front and rear of the vehicle body 11. The coupling device 61 may also be provided at either the front or the rear of the vehicle body 11.

[0044] The coupling device 61 includes, for example, a lifting device 63 that supports the work device 2 so that it can be raised and lowered. The lifting device 63 can change the relative position between the vehicle body 11 and the work device 2 by raising and lowering the work device 2 relative to the vehicle body 11. The lifting device 63 can be coupled to the work device 2. In the example shown in Figures 3 and 4, the lifting device 63 is provided at the rear of the vehicle body 11.

[0045] Figure 7 is a perspective view of the lifting device 63 from the rear. The lifting device 63 includes a lift arm 63a, a lower link 63b, a top link 63c, a lift rod 63d, and a lift cylinder 63e.

[0046] The front end of the lift arm 63a is supported on the upper rear of the vehicle body 11 so as to be able to swing upward or downward. The lift arm 63a swings (rises and falls) by the drive of the lift cylinder 63e. The lift cylinder 63e is made up of a hydraulic cylinder. The lift cylinder 63e is connected to a hydraulic pump via a lift control valve 63f. The lift control valve 63f is a solenoid valve or the like, which changes the hydraulic fluid supplied from the hydraulic pump to the lift cylinder 63e or the hydraulic fluid discharged from the lift cylinder 63e, thereby extending and retracting the lift cylinder 63e.

[0047] The front end of the lower link 63b is supported on the lower rear of the vehicle body 11 so as to be able to swing upward or downward. The front end of the top link 63c is supported on the rear of the vehicle body 11, above the lower link 63b, so as to be able to swing upward or downward. The lift rod 63d connects the lift arm 63a and the lower link 63b. The rear ends of the lower link 63b and the top link 63c are formed in a hook shape.

[0048] When the lift cylinder 63e is driven (extends), the lift arm 63a moves up and down, and the lower link 63b, which is connected to the lift arm 63a via the lift rod 63d, also moves up and down. As a result, the work device 2 swings (moves up and down) upward or downward, with the front of the lower link 63b as the pivot point.

[0049] The work device 2 is connected to the vehicle body 11 by a coupling device 61 and is a device that performs work. The work device 2 includes a tilling device for tilling, a furrowing device for making ridges, a furrowing device for making furrows, a harvesting device for harvesting crops, a mowing device for cutting pasture grass, a spreading device for spreading pasture grass, a grass collecting device for collecting pasture grass, a shaping device for shaping pasture grass, a fertilizer spreading device for spreading fertilizer, a pesticide spraying device for spraying pesticides, a crop separation device for separating crops, and a trolley capable of carrying materials, etc.

[0050] As shown in Figures 3 and 4, the work device 2 mounted on the rear of the vehicle body 11 is sometimes called the rear work device 2A (rear impulse), and the work device 2 mounted on the front of the vehicle body 11 is sometimes called the front work device 2B (front impulse). For example, a front work device 2B (front impulse) could be a front loader, but is not limited to that.

[0051] As shown in Figure 1, the battery unit 71 is capable of supplying power to drive the work vehicle 1. For example, the battery unit 71 has a second battery 72 (sub-battery, range extender) to supplement the first battery 111 provided in the vehicle body 11. The second battery 72 is rechargeable and is a secondary battery such as a lithium-ion battery or a lead-acid battery. The second battery 72 has a plurality of cells inside, and the plurality of cells are electrically connected in series and parallel. In this embodiment, the second battery 72 It stores power supplied via an external charger and supplies the stored power to the electric motor 34 directly or indirectly via the first battery 111.

[0052] The battery unit 71 only needs to be capable of supplying power to drive the work vehicle 1, and the second battery 72 may store the power generated by the fuel cell. In such a case, the battery unit 71 has, in addition to the second battery 72, a tank for containing gas (e.g., hydrogen gas, methane gas, etc.) and a fuel cell (fuel cell stack) that generates electricity from the gas supplied from the tank.

[0053] The equipment and devices mounted on the work vehicle 1 will be described in detail below, mainly using Figure 1. As shown in Figure 1, the work vehicle 1 is equipped with a control device 101. The work vehicle 1 is also equipped with a storage device 102.

[0054] The control device 101 includes one or more processors. The control device 101 is a controller for the work vehicle 1 and performs various controls related to the work vehicle 1. The control device 101 is communicably connected to each device and equipment mounted on the work vehicle 1 via an in-vehicle network such as CAN, ISOBUS, LIN, or FlexRay. The control device 101 can acquire the status of each device and equipment via the in-vehicle network. For example, the control device 101 can acquire information indicating the mounting status of the work device 2 (whether it is mounted or not, front-mounted, and rear-mounted) and information indicating the type of work device 2 (direct-mounted type, towed type) via the in-vehicle network. Alternatively, the control device 101 may acquire this information by inputting it through an input device (a display unit 103a having a touch panel, which will be described later).

[0055] The control device 101 includes one or more memories, various analog circuits, various digital circuits, etc. One or more memories store (remember) software programs and various data to be executed by one or more processors. The control device 101 can read software programs from one or more memories using one or more processors and execute various processes based on said software programs. The control device 101 may also execute various processes based on predetermined logic circuits using one or more processors.

[0056] Processors include, for example, CPUs (Central Processing Units), GPUs (Graphics Processing Units), DSPs (Digital Signal Processors), FPGAs (Field Programmable Gate Arrays), and ASICs (Application Specific Integrated Circuits).

[0057] The control device 101 may perform various processes through the cooperation of multiple physically separated processors, and its configuration is not limited to the configuration described above. In such a case, the multiple processors are each mounted on one or more computers physically separated from the work vehicle 1, and these processors are connected to each other via a network such as an in-vehicle network, LAN, WAN, and the Internet.

[0058] Furthermore, the software program may be stored in a storage device 102 that is communicably connected to the control device 101, or in an external server device connected via the network, and then installed into the memory from these devices.

[0059] The storage device 102 is a device capable of storing information. The storage device 102 is a non-volatile memory such as an HDD (Hard Disk Drive) or SSD (Solid State Drive). The storage device 102 is connected to the control device 101 in a communicative manner, and the control device 101 stores various information in the storage device 102 and retrieves information stored in the storage device 102.

[0060] As shown in Figure 1, the work vehicle 1 is equipped with a display device 103. The display device 103 consists of a display unit 103a, such as a liquid crystal display. The display device 103 is controlled by the control device 101 and displays various information related to the work vehicle 1. The display device 103 is located around the driver's seat 12. A touch panel may be provided on the display unit 103a of the display device 103.

[0061] As shown in Figure 1, the work vehicle 1 may be equipped with a sensing device 104 that detects the surrounding conditions. The sensing device 104 is connected to a control device 101 via wired or wireless communication and outputs sensing results to the control device 101. Based on the sensing results from the sensing device 104, the control device 101 can detect obstacles around the work vehicle 1 or estimate the position of the work vehicle 1 based on the sensing results (detected point cloud data) and environmental map information stored in a storage device 102, etc. In the following description, the position of the work vehicle 1 estimated by the sensing results may be referred to as the estimated position.

[0062] The sensing device 104 includes an optical distance measuring sensor and a signal processing circuit, etc. An example of the optical distance measuring sensor in the sensing device 104 is a LiDAR (Light Detection and Ranging) sensor.

[0063] LiDAR (laser sensors) emit pulsed measurement light (laser beam) millions of times per second from a light source such as a laser diode. This measurement light is reflected by a rotating mirror and scanned horizontally or vertically, projecting it into a predetermined detection range (sensing range, e.g., 360°). The LiDAR then receives the reflected light from the object using a photodetector. The signal processing circuit detects the distance to the object based on the time from when the LiDAR emits the measurement light until the reflected light is received (Time of Flight (ToF) method).

[0064] In addition to LiDAR, other examples of optical distance measuring sensors for the sensing device 104 include imaging devices such as CCD cameras equipped with CCD (Charge Coupled Devices) image sensors, CMOS cameras equipped with CMOS (Complementary Metal Oxide Semiconductor) image sensors, and ToF cameras. Furthermore, although the above example illustrates a case where the sensing device 104 has an optical distance measuring sensor, an ultrasonic distance measuring sensor (for example, an airborne ultrasonic sensor such as sonar) may be used instead of an optical distance measuring sensor.

[0065] Furthermore, as shown in Figure 1, the work vehicle 1 may be equipped with a positioning device 105. The positioning device 105 is a device that performs positioning (detection of the position of the work vehicle 1) of the work vehicle 1. The positioning device 105 is communicably connected to the control device 101 and outputs the position of the work vehicle 1 that it has positioned to the control device 101. The positioning device 105 receives satellite signals from the satellite positioning system using a GPS antenna and performs positioning of the work vehicle 1 using said satellite signals. As positioning of the work vehicle 1, the positioning device 105 performs positioning of a predetermined position on the work vehicle 1. In the following description, the position of the work vehicle 1 that the positioning device 105 has positioned may be referred to as the positioning position. In addition to the positioning position, the positioning device 105 may also detect the orientation of the work vehicle 1 (for example, the orientation in which the front of the vehicle body 11 faces, the vehicle orientation).

[0066] As shown in Figure 1, the work vehicle 1 may be equipped with an attitude detection device 106. The attitude detection device 106 is a device that detects the attitude of the work vehicle 1 (vehicle body 11). The attitude detection device 106 is communicatively connected to the control device 101 and outputs the detected attitude of the vehicle body 11 to the control device 101. Specifically, the attitude detection device 106 detects the three-dimensional inertial motion of the vehicle body 11 as the attitude of the vehicle body 11. The attitude detection device 106 is an inertial measurement unit (IMU) that includes, for example, an acceleration sensor and a gyroscope. The attitude detection device 106 detects the tilt information (roll angle, pitch angle, and yaw angle) of the vehicle body 11.

[0067] As shown in Figure 1, the work vehicle 1 is equipped with an input interface E. The input interface E accepts information input. The input interface E is also connected to the control device 101 for communication and outputs the received information to the control device 101.

[0068] The input interface E accepts operations from, for example, an operator and outputs information (operation information, operation signals) based on those operations to the control device 101. In such cases, the input interface E includes one or more operating devices that accept operations from the operator. The operating devices are either hardware types such as physical levers or switches, or software types such as display images that are displayed and operable on the display unit 103a of the display device 103. Software-type operating devices accept operations when the operator operates a touch panel.

[0069] As shown in Figure 1, the control device 101 has a driving control unit 101a. The driving control unit 101a acquires information received by the input interface E and controls each device and equipment of the work vehicle 1 according to that information. The control device 101 is configured to function as a driving control unit 101a by having one or more processors execute a program. The input interface E and specific examples of the control performed by the driving control unit 101a based on the information received by the input interface E will be described below.

[0070] The input interface E receives input of travel instructions related to travel by the travel device 21. When the input interface E receives input of a travel instruction, the travel control unit 101a acquires the travel instruction and controls the travel by the travel device 21. An example of a travel instruction is an operation instruction for the power unit 31.

[0071] The input interface E that receives operation instructions (driving instructions) for the power unit 31 is the accelerator control device 32. The accelerator control device 32 receives operation instructions for the power supplied from the power unit 31 to the driving unit 21. The accelerator control device 32 has, for example, an accelerator pedal or an accelerator lever, and detects these operations (direction of operation, amount of operation, etc.) using sensors and outputs them as operation signals to the control device 101.

[0072] When the driving control unit 101a receives an operation signal (driving instruction, operation instruction) from the accelerator control device 32, it controls the power unit 31 based on the operation signal and a predetermined control table or calculation formula stored in the memory device 102. Specifically, the driving control unit 101a controls the rotational speed of the electric motor 34 and controls the driving unit 21 based on the operation signal from the accelerator control device 32.

[0073] The driving control unit 101a controls the inverter 74 in response to the operation signal from the accelerator pedal 32, and can arbitrarily change the current and voltage of the power supplied to the electric motor 34. For example, as the amount of operation of the accelerator pedal 32 increases, the driving control unit 101a increases the power supplied to the electric motor 34 and increases the rotational speed of the electric motor 34. On the other hand, as the amount of operation of the accelerator pedal 32 decreases, the driving control unit 101a decreases the power supplied to the electric motor 34 and decreases the rotational speed of the electric motor 34.

[0074] The driving instruction can be any operation instruction related to driving by the driving device 21, and is not limited to operation instructions for the power unit 31. For example, as shown in Figure 2, if the driving control unit 101a is capable of controlling the braking device 51, the input interface E may accept an operation instruction for the braking device 51 as a driving instruction.

[0075] The braking device 51 shown in Figure 2 has a hydraulic actuation unit 54. The hydraulic actuation unit 54 is supplied with hydraulic fluid. The hydraulic actuation unit 54 is operated by and also operates the braking mechanism 53. The hydraulic actuation unit 54 includes a first hydraulic actuation unit 54a that operates the first braking mechanism 53a and a second hydraulic actuation unit 54b that operates the second braking mechanism 53b. The first hydraulic actuation unit 54a and the second hydraulic actuation unit 54b are, for example, brake master cylinders. In Figure 2, there are two hydraulic actuation units, the first hydraulic actuation unit 54a and the second hydraulic actuation unit 54b, but a single hydraulic actuation unit 54 (for example, a brake master cylinder) may operate both the first braking mechanism 53a and the second braking mechanism 53b.

[0076] A first brake control valve 55a is connected to the first hydraulic actuation unit 54a via an oil passage. The first brake control valve 55a is, for example, a solenoid valve and is controlled by the travel control unit 101a to actuate the first hydraulic actuation unit 54a. On the other hand, a second brake control valve 55b is connected to the second hydraulic actuation unit 54b via an oil passage. The second brake control valve 55b is, for example, a solenoid valve and is controlled by the travel control unit 101a to actuate the first hydraulic actuation unit 54a.

[0077] The input interface E that receives operation instructions (driving instructions) for the braking mechanism 53 is, for example, a brake operating device 52. In this case, the brake operating device 52 detects the operation (direction of operation, amount of operation, etc.) of the brake pedal 52a and the parking brake 56, etc., using a sensor, and outputs it to the control device 101 as an operation signal.

[0078] When the driving control unit 101a receives an operation signal (driving instruction, operation instruction) from the brake operating device 52, it performs regenerative cooperative brake control based on a predetermined control table and calculation formula stored in the storage device 102, the operation signal, and the rotational speed of each electric motor 34. Regenerative cooperative brake control is a brake control method that coordinates the braking force (hydraulic braking force) from the braking mechanism 53 (hydraulic brake) and the braking force (regenerative braking force) from regeneration to obtain a braking force corresponding to the operation signal from the brake operating device 52.

[0079] The driving control unit 101a calculates the braking force based on the operation signal from the brake operating device 52 and the rotational speed of each electric motor 34, and uses the control table and calculation formula to calculate and distribute the braking force into regenerative braking force and hydraulic braking force, thereby generating regenerative braking force and hydraulic braking force. For example, in the case of a weak brake operation (when the amount of operation of the brake operating device 52 is the first operation amount), the driving control unit 101a generates only regenerative braking force, and in the case of a strong brake operation (when the amount of operation of the brake operating device 52 is the second operation amount which is greater than the first operation amount), it generates both regenerative braking force and hydraulic braking force.

[0080] Specifically, the driving control unit 101a generates regenerative braking force by putting the electric motor 34 into a regenerative state until the rotational speed of the electric motor 34 is suppressed (reduced) to a target rotational speed. The regenerative state is a state in which the kinetic energy of the vehicle body 11 is recovered as electrical energy by rotating the electric motor 34 with the kinetic energy of the vehicle body 11. Regenerative braking in an electric motor with rotational speed control generates a negative torque in the electric motor 34 to charge the battery by setting "target rotational speed < actual rotational speed". Furthermore, the system controls the braking to prevent sudden braking by setting a threshold for this negative torque (negative value) or a threshold for the rate of change of rotational speed (amount of change of rotational speed per unit time). In addition, the driving control unit 101a outputs a control signal corresponding to the hydraulic braking force to the braking control valve (first braking control valve 55a and / or second braking control valve 55b), and activates the braking mechanism 53 to generate hydraulic braking force (i.e., apply the hydraulic brakes). In regenerative braking coordinated braking control, regenerative braking is performed in the first half of the braking period, and hydraulic braking is performed after the regenerative braking. However, regenerative braking and hydraulic braking may be performed simultaneously throughout the entire braking period, or at least in the latter half of the braking period.

[0081] Regarding hydraulic braking force, as the amount of operation of the brake pedal 52a increases, the driving control unit 101a reduces the opening of the first brake control valve 55a and the second brake control valve 55b. The hydraulic actuation unit 54 increases the braking force of the braking mechanism 53. On the other hand, as the amount of operation of the brake pedal 52a decreases, the driving control unit 101a increases the opening of the first brake control valve 55a and the second brake control valve 55b, and the hydraulic actuation unit 54 decreases the braking force of the braking mechanism 53.

[0082] Figure 8 shows another example of devices and equipment related to the running gear 21. The running gear 21 shown in Figure 8 may be configured without the first braking mechanism 53a, the second braking mechanism 53b, the hydraulic actuation unit 54, the first braking control valve 55a, and the second braking control valve 55b. The running control unit 101a may stop the running vehicle body 11 by stopping the electric motor 34. In other words, the function of stopping the electric motor 34 by the running control unit 101a corresponds to the braking mechanism 53.

[0083] The input interface E that receives operation instructions (driving instructions) for the steering device 41 is, for example, a steering control device 42. In this case, the steering control device 42 detects the rotation direction and rotation angle of the steering wheel 42a using a sensor and outputs it to the control device 101 as an operation signal.

[0084] When the driving control unit 101a receives an operation signal (steering instruction, operation instruction) from the steering control device 42, it controls the steering of the front wheels 22F based on the operation signal and a predetermined control table or calculation formula stored in the storage device 102. Specifically, the driving control unit 101a changes the steering of the front wheels 22F by switching the steering control valve 44 in response to the operation signal from the steering control device 42 and moving the arm 46 in accordance with the extension and retraction of the steering cylinder 45.

[0085] More specifically, as the amount of steering wheel 42a is operated increases, the driving control unit 101a increases the opening of the steering control valve 44, and the steering cylinder 45 increases the steering angle. Conversely, as the amount of steering wheel 42a is operated decreases, the driving control unit 101a decreases the opening of the steering control valve 44, and the steering cylinder 45 decreases the steering angle.

[0086] Furthermore, the input interface E may accept, in addition to or instead of, travel instructions, work instructions related to work performed by the work device 2. When the input interface E receives a work instruction, the travel control unit 101a acquires the work instruction and controls the work performed by the work device 2. An example of a work instruction is an operation instruction for the lifting device 63.

[0087] The input interface E that receives operation instructions (work instructions) for the lifting device 63 is the lifting control device 62. The lifting control device 62 receives operations to raise or lower the lifting device 63. The lifting control device 62 has a lifting lever, and a sensor detects the operation of the lifting lever (direction of operation and amount of operation) and outputs it as an operation signal to the control device 101. The lifting control device 62 may also have a lifting switch in addition to the lifting lever, and the operation signal detected by the lifting switch may also be output to the control device 101.

[0088] When the travel control unit 101a receives an operation signal (work instruction, operation instruction) from the lifting device 62, it controls the lifting device 63 based on the operation signal and a predetermined control table or calculation formula stored in the storage device 102. Specifically, the travel control unit 101a controls the lifting control valve 63f in response to the operation signal from the lifting device 62, and can change the amount of hydraulic fluid supplied from the hydraulic pump to the lift cylinder 63e via the lifting control valve 63f, or the amount of hydraulic fluid discharged from the lift cylinder 63e via the lifting control valve 63f.

[0089] The work instructions may be any operational instructions relating to work performed by the work device 2, and are not limited to operational instructions for the lifting device 63. For example, the input interface E may accept an input of an operational instruction for the rotational speed of the PTO shaft 36 as a work instruction.

[0090] The input interface E that receives operation instructions (work instructions) for the rotation speed of the PTO shaft 36 is a rotary operating device 33. The rotary operating device 33 has, for example, a dial that can be switched to multiple positions, and a sensor detects the operation (switching position) of the dial, etc., and outputs it to the control device 101 as an operation signal.

[0091] When the travel control unit 101a receives an operation signal (work instruction, travel instruction) from the rotary operating tool 33, it controls the fifth electric motor 34e that rotates the PTO shaft 36 based on the operation signal and a predetermined control table or calculation formula stored in the storage device 102.

[0092] Specifically, the travel control unit 101a controls the inverter 74 in response to the operation signal from the rotary operating tool 33, and arbitrarily changes the current and voltage of the power supplied to the fifth electric motor 34e. For example, as the amount of operation of the rotary operating tool 33 increases, the travel control unit 101a increases the power supplied to the fifth electric motor 34e, increasing the rotational speed of the PTO shaft 36. On the other hand, as the amount of operation of the rotary operating tool 33 decreases, the travel control unit 101a decreases the power supplied to the fifth electric motor 34e, decreasing the rotational speed of the PTO shaft 36.

[0093] Furthermore, the input interface E is not limited to the examples described above, and may include operation switches for starting and ending automatic driving control, etc., if the work vehicle 1 is capable of operating with automatic driving control.

[0094] Furthermore, the input interface E only needs to be able to accept information input and output the received information to the control device 101, and is not limited to an operating device that accepts operation by an operator. For example, the input interface E may include a communication device 107 that receives information transmitted from an external source. The communication device 107 is the communication interface of the work vehicle 1 and includes a communication circuit. The communication device 107 wirelessly communicates with an external server device, mobile terminal, remote control device, etc., using, for example, Wi-Fi (Wireless Fidelity, registered trademark) of the IEEE 802.11 series, a mobile phone communication network, or a data communication network. The communication device 107 communicates wirelessly with the server device, etc., and receives various information, data, and signals. The communication device 107 may also serve as an output interface capable of outputting (transmitting) various information, data, and signals to the server device, etc.

[0095] For example, if the work vehicle 1 is capable of operation by remote driving control, the communication device 107 receives operation instructions (driving instructions and / or work instructions) transmitted from the remote control device and outputs these operation instructions as operation signals to the control device 101. As a result, when the driving control unit 101a receives each operation signal (operation instruction), it controls each device and equipment based on that operation signal. Also, if the work vehicle 1 is capable of operation by automatic driving control, the communication device 107 receives operation instructions (driving instructions and / or work instructions) transmitted from the remote control used to start and end automatic driving control, etc., and outputs these operation instructions as operation signals to the control device 101. As a result, when the driving control unit 101a receives each operation signal (operation instruction), it controls the start and end of automatic driving control, etc., based on that operation signal.

[0096] Here, the detailed configuration and driving control of the driving control unit 101a will be explained using Figures 9A and 9B. Figure 9A shows the driving control unit 101a and peripheral equipment of the work vehicle 1. Figure 9B shows that the driving control unit 101a controls the electric motor 34 and the braking mechanism 53.

[0097] As shown in Figures 1 and 9A, the work vehicle 1 is equipped with one or more rotation detection devices 108. The rotation detection devices 108 are communicatively connected to the control device 101 and output the detection results to the control device 101. The rotation detection devices 108 detect the rotation of the travel device 21. The rotation detection device 108 is, for example, an optical or magnetic rotation sensor. For example, the rotation detection device 108 detects the rotation of the traveling device 21 as a pulse signal and outputs the pulse signal to the control device 101. In this embodiment, the rotation detection device 108 is provided on the output shaft of each electric motor 34.

[0098] As shown in Figure 9A, the driving control unit 101a includes an actual vehicle speed calculation unit 101a1, a target vehicle speed calculation unit 101a2, a motor control unit 101a3, and a braking force calculation unit 101a4.

[0099] The actual vehicle speed calculation unit 101a1 calculates the actual speed of the running gear 21. For example, the actual vehicle speed calculation unit 101a1 calculates the rotational speed of the running gear 21 per predetermined time based on the detection result output from the rotational speed detection device 108, and calculates the actual vehicle speed of the running gear 21 from the calculated rotational speed of the running gear 21. Here, the actual vehicle speed is obtained from the rotational speed detection device 108 (i.e., the wheel speed sensor) (i.e., the actual vehicle speed is detected), but this is not the only option. For example, as a modified example, an inverter 74 (or control device 101) calculates the motor rotational speed from the current value, frequency and the specifications of the electric motor 34, and calculates the actual rotational speed by multiplying the calculated rotational speed of the electric motor 34 (motor RPM) by the gear ratio.

[0100] The target vehicle speed calculation unit 101a2 calculates the target vehicle speed of the running gear 21 based on the amount of operation of the accelerator pedal 32 and the actual vehicle speed of the running gear 21 calculated by the actual vehicle speed calculation unit 101a1. For example, the target vehicle speed increases in proportion to the amount of operation of the accelerator pedal 32.

[0101] The motor control unit 101a3 calculates the target rotational speed of each electric motor 34 from the target vehicle speed calculated by the target vehicle speed calculation unit 101a2. As shown in Figures 9A and 9B, the motor control unit 101a3 controls each inverter 74 to change the power supplied to each electric motor 34 (first electric motor 34a to fourth electric motor 34d) to power required to achieve the target rotational speed, thereby setting each electric motor 34 to the target rotational speed.

[0102] The braking force calculation unit 101a4 calculates the braking force based on the amount the brake pedal 52a is pressed and the rotational speed of each electric motor 34 detected by the rotation detection device 108, and then calculates how to distribute the braking force between regenerative braking force and hydraulic braking force. The target vehicle speed calculation unit 101a2 calculates the rotational speed corresponding to the regenerative braking force. The motor control unit 101a3 puts each inverter 74 into a regenerative state until the rotational speed of each electric motor 34 reaches the rotational speed corresponding to the target vehicle speed, which is a value smaller than the actual vehicle speed calculated by the target vehicle speed calculation unit 101a2. If hydraulic braking force is allocated, after regenerative braking of each electric motor 34, the braking force calculation unit 101a4 outputs a control signal corresponding to the hydraulic braking force to the braking control valve (the first braking control valve 55a and / or the second braking control valve 55b shown in Figure 2), and as shown in Figures 9A and 9B, the hydraulic actuation unit 54 (brake master cylinder) operates the braking mechanism 53 (first braking mechanism 53a and second braking mechanism 53b) with the hydraulic braking force.

[0103] The rotation detection device 108 may also detect the rotation of the axle of the wheel 22 or the rotation of a predetermined gear in the power transmission path from the electric motor 34 that drives the wheel 22 to the wheel 22. For example, if the rotation detection device 108 detects the rotation of a predetermined gear in the power transmission path, the actual vehicle speed calculation unit 101a1 converts the rotation of the gear into the rotation of each wheel 22 based on a predetermined calculation formula or the like stored in the memory device 102.

[0104] Now, when the single brake indicator 57 is operated, the driving control unit 101a controls the electric motor 34 corresponding to the inner wheel to suppress the rotation speed of the inner wheel located in the steering direction using the steering control unit 42, based on whether or not the brake operating device 52 is being operated.

[0105] In other words, when the driving control unit 101a receives an input from the input unit 57A while braking force is applied to both wheels (left and right wheels 22) by brake operation (operation by the brake operating device 52), it controls the electric motor 34 corresponding to the inner wheel to suppress the rotation speed of the inner wheel located in the steering direction of the steering operating device 42. For example, the driving control unit 101a further suppresses the rotation speed of the inner wheel. "Further suppressing the rotation speed of the inner wheel" here means suppressing the rotation speed of the inner wheel to a rotation speed lower than the rotation speed due to braking, or to a rotation speed lower than the rotation speed immediately before the input from the input unit 57A.

[0106] A first example of the driving control process will be explained using Figures 10A and 11. Figure 10A is a flowchart showing a first example of the driving control process by the driving control unit 101a. Figure 11 is a diagram showing the first determination table TB1. For example, as shown in Figure 11, the storage device 102 stores the first determination table TB1 which defines the determination of whether or not to perform single-sided braking and the details of single-sided braking. The first determination table TB1 stores that if the single-sided braking indicator 57 is operated, and the steering angle of the steering control device 42 is greater than or equal to a predetermined angle, and the brake control device 52 is operated (pressed down), the operation of the single-sided braking indicator 57 is enabled, and if the brake control device 52 is not operated (not pressed down), the operation of the single-sided braking indicator 57 is disabled.

[0107] The driving control unit 101a uses the first determination table TB1 shown in Figure 11 to determine whether or not to perform single-sided braking and to determine whether to perform single-sided braking. The driving control unit 101a activates the operation of the single-sided brake indicator 57 and performs single-sided braking if the single-sided brake indicator 57 is operated, the steering angle of the steering control device 42 is greater than or equal to a predetermined angle (turn start angle), and the brake control device 52 is operated (pressed down). On the other hand, if the brake control device 52 is not operated (not pressed down), the driving control unit 101a deactivates the operation of the single-sided brake indicator 57 and does not perform single-sided braking.

[0108] As shown in Figure 10A, the driving control unit 101a determines whether or not the single brake indicator 57 has been operated (S11). If the single brake indicator 57 has not been operated (No in S11), the driving control unit 101a returns to S11. On the other hand, if the single brake indicator 57 has been operated (Yes in S11), the driving control unit 101a determines whether or not the steering angle of the steering control device 42, as detected by the steering angle detection device 47, is greater than or equal to a predetermined angle (S12).

[0109] The driving control unit 101a determines whether the brake lever 52 has been operated (S13) if the steering angle of the steering lever 42 is greater than or equal to a predetermined angle (Yes in S12). If the brake lever 52 has been operated (Yes in S13), the driving control unit 101a controls the electric motor 34 corresponding to the inner wheel to suppress the rotation speed of the inner wheel located in the steering direction of the steering lever 42 (S14).

[0110] For example, when the single brake indicator 57 is operated (Yes in S11), the brake operating device 52 is operated (Yes in S13), and the steering device 42 is used to steer the vehicle to the left, the driving control unit 101a controls the first electric motor 34a and the third electric motor 34c corresponding to the inner wheels to suppress the rotational speed of the inner wheels, the left front wheel 22F1 and the left rear wheel 22R1 (for example, by reducing the rotational speed by 10%). Specifically, the driving control unit 101a puts the second electric motor 34b and the fourth electric motor 34d into a regenerative state for the outer wheels, the right front wheel 22F2 and the right rear wheel 22R2, until their rotational speeds reach the rotational speeds corresponding to the regenerative braking force calculated by the aforementioned braking force calculation unit 101a4 and target vehicle speed calculation unit 101a2. At the same time, it puts the first electric motor 34a and the third electric motor 34c into a regenerative state for the inner wheels, the left front wheel 22F1 and the left rear wheel 22R1, until their rotational speeds are reduced by a further 10% from the rotational speeds corresponding to the regenerative braking force.

[0111] Furthermore, if the steering is set to turn to the right, the driving control unit 101a will control the left front wheel, which is the outer wheel. The first electric motor 34a and the third electric motor 34c are set to regenerative mode until the rotational speed of 22F1 and the left rear wheel 22R1 reaches a rotational speed corresponding to the regenerative braking force, and the second electric motor 34b and the fourth electric motor 34d corresponding to the inner wheels, the right front wheel 22F2 and the right rear wheel 22R2, are set to regenerative mode to suppress the rotational speed of the inner wheels (for example, by 10% reduction in rotational speed).

[0112] On the other hand, if the answer is No in S12 or No in S13, the driving control unit 101a does not suppress the rotation speed of the inner wheel (S15). In other words, if the brake operating device 52 is not operated (not pressed), the driving control unit 101a disables the operation of the single brake indicator 57 and does not perform single braking.

[0113] In this case, work vehicle 1 is four-wheel drive (4WD), and the rotation speed of the inner wheels (left front wheel 22F1 and left rear wheel 22R1, or right front wheel 22F2 and right rear wheel 22R2) is suppressed. If work vehicle 1 is two-wheel drive (2WD), the rotation speed of the inner drive wheels is suppressed. For example, in the case of rear-wheel drive, the rotation speed of the inner drive wheels (left rear wheel 22R1, or right rear wheel 22R2) is suppressed, and in the case of front-wheel drive, the rotation speed of the inner drive wheels (left front wheel 22F1, or right front wheel 22F2) is suppressed.

[0114] Next, a second example of the driving control process will be explained using Figures 10B and 12. Figure 10B is a flowchart of the second example of the driving control process. Figure 12 is a diagram of the second decision table TB2. For example, as shown in Figure 12, the storage device 102 stores a second decision table TB2 which defines the execution details of single-sided braking. The second decision table TB2 stores that strong single-sided braking is executed when the single-sided brake indicator 57 is operated, the steering angle of the steering control device 42 is greater than or equal to a predetermined angle, and the brake control device 52 is operated (pressed down), and weak single-sided braking is executed when the brake control device 52 is not operated (not pressed down).

[0115] When the single brake indicator 57 is operated, the driving control unit 101a reduces the rotational speed of the inner wheel to a rotational speed corresponding to a first suppression ratio (e.g., a 20% reduction in rotational speed) if the brake operating device 52 is also operated, and reduces the rotational speed of the inner wheel to a rotational speed corresponding to a second suppression ratio (e.g., a 10% reduction in rotational speed) which is smaller than the first suppression ratio, if the brake operating device 52 is not operated. Note that the rotational speed reduction for the first suppression ratio is set at 20%, but it may be other than 20%. The rotational speed reduction for the second suppression ratio is set at 10%, but it may be other than 10% as long as it is smaller than the first suppression ratio.

[0116] The driving control unit 101a uses the second determination table TB2 shown in Figure 12 to determine the content of the single-sided braking. If the single-sided braking indicator 57 is operated, the steering angle of the steering control device 42 is greater than or equal to a predetermined angle (turn start angle), and the brake control device 52 is operated (pressed down), the driving control unit 101a reduces the rotational speed of the inner wheel to a rotational speed corresponding to the first suppression ratio (e.g., 20% reduction in rotational speed) and performs strong single-sided braking. On the other hand, if the brake control device 52 is not operated (not pressed down), the driving control unit 101a reduces the rotational speed of the inner wheel to a rotational speed corresponding to the second suppression ratio (e.g., 10% reduction in rotational speed) and performs weak single-sided braking.

[0117] Steps S21 to S23 in Figure 10B are the same as steps S11 to S13 in Figure 10A, so their explanation is omitted here. In step S23 in Figure 10B, the driving control unit 101a controls the electric motor 34 corresponding to the inner wheel to reduce the rotational speed of the inner wheel located in the steering direction of the steering control unit 42 to a rotational speed corresponding to a first suppression ratio (for example, a 20% reduction in rotational speed) (S24), and performs strong single-sided braking.

[0118] For example, when the single brake indicator 57 is operated, the driving control unit 101a will react (in S21) If the brake lever 52 is operated (Yes in S23) and the steering lever 42 is used to steer the vehicle to the left, the first electric motor 34a and the third electric motor 34c corresponding to the inner wheels are controlled to suppress the rotational speed of the inner wheels, the left front wheel 22F1 and the left rear wheel 22R1 (for example, by reducing the rotational speed by 20%). In other words, the second electric motor 34b and the fourth electric motor 34d enter a regenerative state so that the outer wheels, the right front wheel 22F2 and the right rear wheel 22R2, reach a rotational speed corresponding to the regenerative braking force calculated by the braking force calculation unit 101a4 and the target vehicle speed calculation unit 101a2 described above. Furthermore, the first electric motor 34a and the third electric motor 34c enter a regenerative state so that the rotational speed of the inner wheels, the left front wheel 22F1 and the left rear wheel 22R1, is suppressed to a rotational speed that is 20% lower than the rotational speed corresponding to the regenerative braking force. Furthermore, when steering to the right, the second electric motor 34b and the fourth electric motor 34d corresponding to the inner wheels are controlled to suppress the rotational speed of the inner wheels, namely the right front wheel 22F2 and the right rear wheel 22R2 (for example, by reducing the rotational speed by 20%).

[0119] On the other hand, if the answer to S23 is No, the driving control unit 101a controls the electric motor 34 corresponding to the inner wheel to reduce the rotational speed of the inner wheel to a rotational speed corresponding to the second suppression ratio (for example, a 10% reduction in rotational speed) (S25) when the single brake indicator 57 is operated (Yes in S21), the steering angle of the steering control device 42 is greater than or equal to a predetermined angle (Yes in S22), and the brake control device 52 is not operated (No in S23), thereby performing a weak single brake.

[0120] On the other hand, if the answer in S22 is No, the driving control unit 101a does not suppress the rotation speed of the inner wheel (S26). In other words, if the steering angle is not greater than or equal to a predetermined angle, the driving control unit 101a disables the operation of the single brake indicator 57 and does not apply single brakes.

[0121] Next, a third example of the driving control process will be explained using Figures 10C and 13. Figure 10C is a flowchart of the third example of the driving control process. Figure 13 is a diagram of the third decision table TB3. For example, as shown in Figure 13, the memory device 102 stores the third decision table TB3 which defines the execution content of single-sided braking. In addition to the second decision table TB2, the third decision table TB3 stores that a pivot turn (pivot turn) or spin turn (super pivot turn) will be executed if the single-sided brake indicator 57 is operated, the steering angle of the steering control device 42 is greater than or equal to a predetermined angle, and the amount of operation of the brake control device 52 is greater than or equal to a predetermined value. The predetermined value can be exemplified by cases such as when the brake control device 52 is pressed all the way down, or when it is pressed down to a position a certain amount before the all the way down.

[0122] When the single brake indicator 57 is operated, the driving control unit 101a controls the rotation speed of the inner wheel to zero or a negative rotation speed if the amount of operation of the brake operating device 52 is greater than or equal to a predetermined value. Specifically, when the single brake indicator 57 is operated, the driving control unit 101a controls the rotation speed of the inner wheel to zero or a negative rotation speed if the amount of operation of the brake operating device 52 is greater than or equal to a predetermined value. When the single brake indicator 57 is operated, if the brake operating device 52 is operated to less than a predetermined value, the driving control unit 101a reduces the rotation speed of the inner wheel to a rotation speed corresponding to a first suppression ratio (e.g., 20% reduction in rotation speed). If the brake operating device 52 is not operated, the driving control unit 101a reduces the rotation speed of the inner wheel to a rotation speed corresponding to a second suppression ratio smaller than the first suppression ratio (e.g., 10% reduction in rotation speed).

[0123] The driving control unit 101a determines the execution of single-sided braking using the third determination table TB3 shown in Figure 13. If the single-sided braking indicator 57 is operated, the steering angle of the steering control device 42 is greater than or equal to a predetermined angle (turn start angle), and the amount of operation of the brake control device 52 is greater than or equal to a predetermined value, the driving control unit 101a suppresses the rotation speed of the inner wheel to zero and executes a pivot turn (pivot turn). In addition, the driving control unit 101a executes a spin turn (super pivot turn) by suppressing the rotation speed of the inner wheel to a negative rotation speed. The execution of strong single-sided braking and single-sided braking is the same as in the second example, so the explanation is omitted.

[0124] Steps S31 to S33 in Figure 10C are the same as steps S21 to S23 in Figure 10B, so their explanation is omitted here. In step S34 in Figure 10C, if the amount of operation of the brake lever 52 is greater than or equal to a predetermined value (Yes in S34), the driving control unit 101a suppresses the rotation speed of the inner wheel located in the steering direction using the steering lever 42 to zero through regenerative coordinated brake control of hydraulic braking force and regenerative braking force, thereby executing a pivot turn (S35). The driving control unit 101a also executes a spin turn by suppressing the rotation speed of the inner wheel to a negative rotation speed (S35). If the amount of operation of the brake lever 52 is not greater than or equal to a predetermined value (No in S34), the driving control unit 101a controls the electric motor 34 corresponding to the inner wheel to reduce the rotation speed of the inner wheel to a rotation speed corresponding to a first suppression ratio (for example, a 20% reduction in rotation speed) (S36), thereby executing strong single-sided braking.

[0125] For example, if the single brake indicator 57 is operated (Yes in S31), steering to the left is performed using the steering control device 42 (Yes in S32), and the amount of operation of the brake control device 52 is greater than or equal to a predetermined value (Yes in S34), the driving control unit 101a controls the first electric motor 34a and the third electric motor 34c corresponding to the inner wheels, the left front wheel 22F1 and the left rear wheel 22R1, to suppress their rotational speeds to zero (or negative rotational speeds) (S35).

[0126] On the other hand, if the answer to S34 is No, the drive control unit 101a reduces the rotational speed of the inner wheel to a rotational speed corresponding to the first suppression ratio (e.g., a 20% reduction in rotational speed) (S36) and applies strong braking. If the brake operating device 52 is not operated (No in S33), the electric motor 34 corresponding to the inner wheel controls the motor to reduce the rotational speed of the inner wheel to a rotational speed corresponding to the second suppression ratio (e.g., a 10% reduction in rotational speed) (S37) and applies weak braking.

[0127] On the other hand, if the answer in S32 is No, the driving control unit 101a does not suppress the rotation speed of the inner wheel (S38). In other words, if the steering angle is not greater than or equal to a predetermined angle, the driving control unit 101a disables the operation of the single brake indicator 57 and does not apply single brakes.

[0128] Next, we will explain a fourth example of the driving control process using Figure 10D. Figure 10D is a flowchart of the fourth example of the driving control process.

[0129] When the single brake indicator 57 is operated, the driving control unit 101a controls the rotation speed of the inner wheel to zero or a negative rotation speed if the amount of operation of the brake operating device 52 is greater than or equal to a predetermined value and the speed of the driving vehicle body 11 is less than or equal to a predetermined speed. The predetermined speed is a speed at which there is no risk of the work vehicle 1 tipping over when the work vehicle 1 pivots, and is, for example, a low speed. Examples of low speeds include 10 km / h, but the speed is not limited to this.

[0130] Steps S41-S44 and S46-S49 shown in Figure 10D are the same as steps S31-S34 and S35-S38 in Figure 10C, so their explanation is omitted here. In step S45 shown in Figure 10D, if the amount of operation of the brake lever 52 is greater than or equal to a predetermined value (Yes in S44) and the speed of the vehicle body 11 is less than or equal to a predetermined speed (Yes in S45), the driving control unit 101a suppresses the rotation speed of the inner wheel located in the steering direction of the steering lever 42 to zero by regenerative coordinated brake control of hydraulic braking force and regenerative braking force, thereby executing a pivot turn (S46). The driving control unit 101a also executes a spin turn by suppressing the rotation speed of the inner wheel to a negative rotation speed (S46).

[0131] On the other hand, if the amount of operation of the brake operator 52 is greater than or equal to a predetermined value (Yes in S44), but the condition that the speed of the vehicle body 11 is less than or equal to a predetermined speed is not met (No in S45), or if the amount of operation of the brake operator 52 is not greater than or equal to a predetermined value (No in S44), the driving control unit 101a controls the electric motor 34 corresponding to the inner wheel to reduce the rotation speed of the inner wheel to a rotation speed corresponding to a first suppression ratio (for example, a 20% reduction in rotation speed) (S47), and performs strong single-sided braking.

[0132] In addition, in S47, the driving control unit 101a may maintain the position of the inner rear wheel or inner front wheel so that it does not change. For example, by performing feedback control to fine-tune the position of the inner wheel by rotating it in the forward direction, zero rotation, or in the reverse direction in response to the displacement of the inner rear wheel or inner front wheel, the position of the inner rear wheel or inner front wheel can be maintained so that it does not change.

[0133] Note that S48 (weak single brake) and S49 (no single brake) are the same as S37 (weak single brake) and S38 (no single brake) in Figure 10C, so their explanation is omitted here.

[0134] Next, we will explain the fifth example of the driving control process using Figure 10E. Figure 10E is a flowchart of the fifth example of the driving control process.

[0135] When the single brake indicator 57 is operated, the driving control unit 101a prohibits controlling the rotation speed of the inner wheel to zero or a negative rotation speed if the amount of operation of the brake operating device 52 is greater than or equal to a predetermined value and the work device 2 connected to the vehicle body 11 is of the towing type, and controls the rotation speed of the inner wheel to zero or a negative rotation speed if the work device 2 connected to the vehicle body 11 is not of the towing type.

[0136] Steps S51-S54 and S56-S59 shown in Figure 10E are the same as steps S41-S44 and S46-S49 in Figure 10D, so their explanation is omitted here. In step S55 shown in Figure 10E, if the amount of operation of the brake lever 52 is greater than or equal to a predetermined value (Yes in S54), and the work device 2 connected to the vehicle body 11 is not of the towing type (Yes in S55), the driving control unit 101a suppresses the rotation speed of the inner wheel located in the steering direction using the steering lever 42 to zero by regenerative coordinated brake control of hydraulic braking force and regenerative braking force, thereby executing a pivot turn (S56). The driving control unit 101a also executes a spin turn by suppressing the rotation speed of the inner wheel to a negative rotation speed (S56).

[0137] On the other hand, if the amount of operation of the brake operator 52 is greater than or equal to a predetermined value (Yes in S54), but the work device 2 connected to the vehicle body 11 is of the towing type (No in S55), or if the amount of operation of the brake operator 52 is not greater than or equal to a predetermined value (No in S54), the driving control unit 101a controls the electric motor 34 corresponding to the inner wheel to reduce the rotation speed of the inner wheel to a rotation speed corresponding to a first suppression ratio (for example, a 20% reduction in rotation speed) (S57), and performs strong single-sided braking.

[0138] Note that S58 (weak single brake) and S59 (no single brake) are the same as S48 (weak single brake) and S49 (no single brake) in Figure 10D, so their explanation is omitted here.

[0139] Next, we will explain the sixth example of the driving control process using Figure 10F. Figure 10F is a flowchart of the sixth example of the driving control process.

[0140] When the single brake indicator 57 is operated, the driving control unit 101a controls the rotation speed of the inner wheel to zero or a negative rotation speed if the amount of operation of the brake operating device 52 is greater than or equal to a predetermined value and the weight of the work device 2 connected to the vehicle body 11 is less than or equal to a predetermined weight. If the weight of the work device 2 connected to the vehicle body 11 is not less than or equal to a predetermined weight, the driving control unit 101a prohibits controlling the rotation speed of the inner wheel to zero or a negative rotation speed.

[0141] Steps S61-S64 and S66-S69 in Figure 10F are the same as steps S51-S54 and S56-S59 in Figure 10E, so their explanation is omitted here. In step S65 in Figure 10F, if the amount of operation of the brake lever 52 is greater than or equal to a predetermined value (Yes in S64), and the weight of the work device 2 connected to the vehicle body 11 is less than or equal to a predetermined weight (Yes in S65), the driving control unit 101a suppresses the rotation speed of the inner wheel located in the steering direction using the steering lever 42 to zero by regenerative coordinated brake control of hydraulic braking force and regenerative braking force, thereby executing a pivot turn (S66). The driving control unit 101a also executes a spin turn by suppressing the rotation speed of the inner wheel to a negative rotation speed (S66).

[0142] On the other hand, if the amount of operation of the brake operating tool 52 is greater than or equal to a predetermined value (Yes in S64), but the weight of the work device 2 connected to the vehicle body 11 is not less than or equal to a predetermined weight (No in S65), or if the amount of operation of the brake operating tool 52 is not greater than or equal to a predetermined value (No in S64), the driving control unit 101a controls the electric motor 34 corresponding to the inner wheel to reduce the rotational speed of the inner wheel to a rotational speed corresponding to a first suppression ratio (for example, a 20% reduction in rotational speed) (S67), and performs strong single-sided braking.

[0143] Note that S68 (weak single brake) and S69 (no single brake) are the same as S58 (weak single brake) and S59 (no single brake) in Figure 10E, so their explanation is omitted here.

[0144] Next, we will explain the seventh example of the driving control process using Figure 10G. Figure 10G is a flowchart of the seventh example of the driving control process.

[0145] When the single brake indicator 57 is operated, the driving control unit 101a controls the rotation speed of the inner wheel to zero or a negative rotation speed, provided that the amount of operation of the brake operating device 52 is greater than or equal to a predetermined value and the inclination angle of the driving vehicle body 11 is less than or equal to a predetermined inclination angle. If the inclination angle of the driving vehicle body 11 is not less than or equal to a predetermined inclination angle, the control unit 101a prohibits controlling the rotation speed of the inner wheel to zero or a negative rotation speed.

[0146] Steps S71-S74 and S76-S79 shown in Figure 10G are the same as steps S61-S64 and S66-S69 in Figure 10F, so their explanation is omitted here. In step S75 shown in Figure 10G, if the amount of operation of the brake lever 52 is greater than or equal to a predetermined value (Yes in S74) and the inclination angle of the vehicle body 11 is less than or equal to a predetermined inclination angle (Yes in S75), the driving control unit 101a suppresses the rotation speed of the inner wheel located in the steering direction of the steering lever 42 to zero by regenerative coordinated brake control of hydraulic braking force and regenerative braking force, thereby executing a pivot turn (S76). The driving control unit 101a also executes a spin turn by suppressing the rotation speed of the inner wheel to a negative rotation speed (S76).

[0147] On the other hand, if the amount of operation of the brake operator 52 is greater than or equal to a predetermined value (Yes in S74), but the inclination angle of the vehicle body 11 is not less than or equal to a predetermined inclination angle (No in S75), or if the amount of operation of the brake operator 52 is not greater than or equal to a predetermined value (No in S74), the driving control unit 101a controls the electric motor 34 corresponding to the inner wheel to reduce the rotation speed of the inner wheel to a rotation speed corresponding to a first suppression ratio (for example, a 20% reduction in rotation speed) (S77), and performs strong single-sided braking.

[0148] Note that S78 (weak single brake) and S79 (no single brake) are the same as S68 (weak single brake) and S69 (no single brake) in Figure 10F, so their explanation is omitted here.

[0149] Next, an eighth example of the driving control process will be explained using Figures 10H and 14. Figure 10H is a flowchart of the eighth example of the driving control process. Figure 14 is a diagram of the fourth decision table TB4. For example, as shown in Figure 14, the storage device 102 stores the fourth decision table TB4 which defines the execution details of single-sided braking. The fourth decision table TB4 stores that strong single-sided braking is performed when the single-sided brake indicator 57 is operated, the steering angle of the steering control device 42 is greater than or equal to a predetermined angle, the brake control device 52 is operated (pressed down), and the work device 2 is not connected to the vehicle body 11, and weak single-sided braking is performed when the work device 2 is connected to the vehicle body 11.

[0150] When the single brake indicator 57 is operated, if the brake operating device 52 is operated and the working device 2 is not connected to the vehicle body 11, the driving control unit 101a reduces the rotation speed of the inner wheel to a rotation speed corresponding to the first suppression ratio, and if the working device 2 is connected to the vehicle body 11, it reduces the rotation speed of the inner wheel to a rotation speed corresponding to a second suppression ratio which is smaller than the first suppression ratio.

[0151] The driving control unit 101a uses the fourth determination table TB4 shown in Figure 14 to determine the content of the single-sided brake application. If the single-sided brake indicator 57 is operated, the steering angle of the steering control device 42 is greater than or equal to a predetermined angle (turning start angle), the brake control device 52 is operated, and the work device 2 is not connected to the vehicle body 11, the driving control unit 101a controls the electric motor 34 corresponding to the inner wheel to reduce the rotation speed of the inner wheel to a rotation speed corresponding to the first suppression ratio (e.g., 20% reduction in rotation speed), and performs strong single-sided braking. On the other hand, if the work device 2 is connected to the vehicle body 11, the driving control unit 101a reduces the rotation speed of the inner wheel to a rotation speed corresponding to the second suppression ratio (e.g., 10% reduction in rotation speed), and performs weak single-sided braking.

[0152] Steps S81-S83 and S85-S87 shown in Figure 10H are the same as steps S21-S26 in Figure 10B, so their explanation is omitted here. In step S84 shown in Figure 10H, if the brake operator 52 is operated (Yes in S83) and the work device 2 is not connected to the vehicle body 11 (Yes in S84), the travel control unit 101a controls the electric motor 34 corresponding to the inner wheel to reduce the rotation speed of the inner wheel to a rotation speed corresponding to a first suppression ratio (e.g., a 20% reduction in rotation speed) (S85), thereby performing strong single-sided braking. On the other hand, if the brake operator 52 is operated (Yes in S83) but the work device 2 is connected to the vehicle body 11 (No in S84), the travel control unit 101a controls the electric motor 34 corresponding to the inner wheel to reduce the rotation speed of the inner wheel to a rotation speed corresponding to a second suppression ratio (e.g., a 10% reduction in rotation speed) (S86), thereby performing weak single-sided braking.

[0153] On the other hand, if the answer is No in S82 or No in S83, the driving control unit 101a does not suppress the rotation speed of the inner wheel (S87). In other words, if the steering angle is not greater than or equal to a predetermined angle, and there is no operation of the brake operating device 52, the driving control unit 101a disables the operation of the single brake indicator 57 and does not perform single braking.

[0154] Next, the ninth example of the driving control process will be explained using Figures 10I and 15. Figure 10I is a flowchart of the ninth example of the driving control process. Figure 15 is a diagram of the fifth decision table TB5. For example, as shown in Figure 15, the storage device 102 stores the fifth decision table TB5 which defines the execution details of single-sided braking. The fifth decision table TB5 stores that if the single-sided brake indicator 57 is operated, the steering angle of the steering control device 42 is greater than or equal to a predetermined angle, the brake control device 52 is operated (pressed down), and the type of work device 2 connected to the vehicle body 11 is a direct-mount type, then strong single-sided braking will be executed, and if the type of work device 2 is a towing type, then weak single-sided braking will be executed.

[0155] When the single brake indicator 57 is operated, if the brake operating device 52 is also operated and the work device 2 connected to the vehicle body 11 is of the direct-mount type, the running control unit 101a reduces the rotation speed of the inner wheel to a rotation speed corresponding to the first suppression ratio, and if the work device 2 is of the towing type, it reduces the rotation speed of the inner wheel to a rotation speed corresponding to a second suppression ratio which is smaller than the first suppression ratio.

[0156] The driving control unit 101a uses the fifth determination table TB5 shown in Figure 15 to determine whether or not to perform single-sided braking and to determine the details of single-sided braking. - If the steering indicator 57 is operated, the steering angle of the steering control device 42 is greater than or equal to a predetermined angle (turning start angle), and the brake control device 52 is operated, and the type of work device 2 connected to the vehicle body 11 is a direct-mount type, the electric motor 34 corresponding to the inner wheel is controlled to reduce the rotation speed of the inner wheel to a rotation speed corresponding to a first suppression ratio (e.g., 20% reduction in rotation speed), and strong single-sided braking is performed. On the other hand, if the type of work device 2 is a towing type, the travel control unit 101a reduces the rotation speed of the inner wheel to a rotation speed corresponding to a second suppression ratio (e.g., 10% reduction in rotation speed), and weak single-sided braking is performed.

[0157] Steps S91-S93 and S95-S97 in Figure 10I are the same as steps S81-S83 and S85-S87 in Figure 10H, so their explanation is omitted here. In step S94 in Figure 10I, if the brake operator 52 is operated (Yes in S93) and the type of work device 2 connected to the vehicle body 11 is a direct-mount type (Yes in S94), the travel control unit 101a controls the electric motor 34 corresponding to the inner wheel to reduce the rotation speed of the inner wheel to a rotation speed corresponding to a first suppression ratio (e.g., a 20% reduction in rotation speed) (S95), and performs strong single-sided braking. On the other hand, if the brake operator 52 is operated (Yes in S93) but the type of work device 2 is a towing type (No in S94), the travel control unit 101a controls the electric motor 34 corresponding to the inner wheel to reduce the rotation speed of the inner wheel to a rotation speed corresponding to a second suppression ratio (e.g., a 10% reduction in rotation speed) (S96), and performs weak single-sided braking.

[0158] On the other hand, if the answer is No in S92 or No in S93, the driving control unit 101a does not suppress the rotation speed of the inner wheel (S97). In other words, if the steering angle is not greater than or equal to a predetermined angle, and there is no operation of the brake operating device 52, the driving control unit 101a disables the operation of the single brake indicator 57 and does not perform single braking.

[0159] Next, the tenth example of the driving control process will be explained using Figures 10J, 16, and 17. Figure 10J is a flowchart of the tenth example of the driving control process. Figure 16 is a diagram of the sixth decision table TB6. Figure 17 is a schematic plan view illustrating the rear wheel single brake and the front wheel single brake. For example, as shown in Figure 16, the memory device 102 stores the sixth decision table TB6, which defines the execution details of the single brake. The sixth decision table TB6 stores that the front wheel single brake will be executed when the single brake indicator 57 is operated, the steering angle of the steering control device 42 is greater than or equal to a predetermined angle, the brake control device 52 is operated (pressed down), and the type of work device 2 connected to the vehicle body 11 is the front work device 2B (front impulse), and the rear wheel single brake will be executed when the type of work device 2 is the rear work device 2A (rear impulse) or when the work device 2 is not installed.

[0160] When the single brake indicator 57 is operated, if the brake operating device 52 is operated and the work device 2 is connected to the front of the vehicle body 11, the driving control unit 101a controls the electric motor 34 corresponding to the front inner wheel to suppress the rotation speed of the front inner wheel. If the work device 2 is connected to the rear of the vehicle body 11 or the work device 2 is not connected to the vehicle body 11, the electric motor 34 corresponding to the rear inner wheel controls the electric motor 34 corresponding to the rear inner wheel to suppress the rotation speed of the rear inner wheel.

[0161] The driving control unit 101a uses the sixth determination table TB6 shown in Figure 16 to determine whether to apply the brake to one wheel. The driving control unit 101a applies the brake to the front wheel if the brake indicator 57 is operated, the steering angle of the steering control device 42 is greater than or equal to a predetermined angle (turning start angle), the brake control device 52 is operated, and the type of work device 2 is the front work device 2B (front impulse), as shown on the right side of Figure 17. On the other hand, the driving control unit 101a applies the brake to the rear wheel if the type of work device 2 is the rear work device 2A (rear impulse), or if the work device 2 is not installed, as shown on the left side of Figure 17.

[0162] Steps S101 to S103 and S107 in Figure 10J are the same as steps S91 to S93 and S97 in Figure 10I, so their explanation is omitted here. In step S104 in Figure 10J, the travel control unit 101a controls the electric motor 34 corresponding to the front inner wheel to suppress the rotation speed of the front inner wheel if the brake operator 52 is operated (Yes in S103) and the type of work device 2 connected to the travel vehicle body 11 is the front work device 2B (front impulse) (Yes in S104) (S105). On the other hand, if the brake operator 52 is operated (Yes in S103), but the type of work device 2 is the rear work device 2A (rear impulse) or the work device 2 is not installed (No in S104), the travel control unit 101a controls the electric motor 34 corresponding to the rear inner wheel to suppress the rotation speed of the rear inner wheel (S106).

[0163] On the other hand, if the answer in S102 is No, or if the answer in S103 is No, the driving control unit 101a does not suppress the rotation speed of the inner wheel (S107). In other words, if the steering angle is not greater than or equal to a predetermined angle, and there is no operation of the brake operating device 52, the driving control unit 101a disables the operation of the single brake indicator 57 and does not perform single braking.

[0164] Alternatively, Figure 10K may be used instead of Figure 10J above, and the 7th decision table TB7 shown in Figure 18 may be used instead of the 6th decision table TB6 shown in Figure 16 above. Figure 10K is a flowchart showing the 11th example of the driving control processing by the driving control unit 101a. Figure 18 is a diagram showing the 7th decision table TB7.

[0165] As shown in Figure 18, the seventh determination table TB7 stores that if the single brake indicator 57 is operated, the steering angle of the steering control device 42 is greater than or equal to a predetermined angle, the brake control device 52 is operated (pressed down), and the type of work device 2 connected to the vehicle body 11 is a front work device 2B (front impulse), the front single brake is set to a strong single brake and the rear single brake is set to a weak single brake. If the type of work device 2 on the vehicle body 11 is a rear work device 2A (rear impulse), the rear single brake is set to a strong single brake and the front single brake is set to a weak single brake.

[0166] When the work device 2 is connected to the front of the vehicle body 11, the driving control unit 101a reduces the rotational speed of the front inner wheel to a rotational speed corresponding to a first suppression ratio (e.g., 20% reduction in rotational speed) and reduces the rotational speed of the rear inner wheel to a rotational speed corresponding to a second suppression ratio smaller than the first suppression ratio (e.g., 10% reduction in rotational speed).

[0167] The travel control unit 101a reduces the rotational speed of the rear inner wheel to a rotational speed corresponding to a first suppression ratio (e.g., 20% reduction in rotational speed) when the work device 2 is connected to the rear of the travel vehicle body 11 or when the work device 2 is not connected to the travel vehicle body 11, and reduces the rotational speed of the front inner wheel to a rotational speed corresponding to a second suppression ratio (e.g., 10% reduction in rotational speed) which is smaller than the first suppression ratio.

[0168] Steps S111 to S114 and S117 shown in Figure 10K are the same as steps S101 to S104 and S107 in Figure 10J, so their explanation is omitted here. In step S114 shown in Figure 10K, the travel control unit 101a controls the electric motor 34 corresponding to the front inner wheel to reduce the rotational speed of the front inner wheel to a rotational speed corresponding to a first suppression ratio (e.g., 20% reduction in rotational speed) and the rotational speed of the rear inner wheel to a rotational speed corresponding to a second suppression ratio (e.g., 10% reduction in rotational speed), which is smaller than the first suppression ratio (S115).

[0169] On the other hand, the running control unit 101a will determine if the brake operating tool 52 is being operated (Yes in S113), but the type of working device 2 is the rear working device 2A (rear impulse) or if the working device 2 If the rear inner ring is not installed (No in S114), the electric motor 34 corresponding to the rear inner ring is controlled to reduce the rotational speed of the rear inner ring to a rotational speed corresponding to a first suppression ratio (e.g., 20% reduction in rotational speed) and to reduce the rotational speed of the front inner ring to a rotational speed corresponding to a second suppression ratio smaller than the first suppression ratio (e.g., 10% reduction in rotational speed) (S116).

[0170] On the other hand, if the answer is No in S112 or No in S113, the driving control unit 101a does not suppress the rotation speed of the inner wheel (S117). In other words, if the steering angle is not greater than or equal to a predetermined angle, and there is no operation of the brake operating device 52, the driving control unit 101a disables the operation of the single brake indicator 57 and does not perform single braking.

[0171] The main characteristic features and effects of the work vehicle 1 in the embodiments described above are as follows:

[0172] (Item A1) A work vehicle 1 comprising a running body 11, a power unit 31 having electric motors 34 that drive each wheel 22 provided on the left and right sides of the running body 11, a brake operating tool 52, a single brake indicator 57, a steering device 41 that steers the running body 11 based on the operation of a steering operating tool 42, and a running control unit 101a, wherein the running control unit 101a controls the electric motor 34 corresponding to the inner wheel to suppress the rotation speed of the inner wheel located in the steering direction of the steering operating tool 42, based on whether or not the brake operating tool 52 is being operated when the single brake indicator 57 is operated.

[0173] With this configuration, it is possible to appropriately determine whether or not to apply single-sided braking based on whether or not the brake operator 52 is operated when the single-sided brake indicator 57 is operated. Furthermore, when the brake operator 52 is operated when the single-sided brake indicator 57 is operated, the rotation speed of the inner wheel located in the steering direction is suppressed by the steering operator 42, so that single-sided braking can be applied appropriately. Therefore, it is possible to appropriately determine whether or not to apply single-sided braking and to apply single-sided braking appropriately.

[0174] (Item A2) The work vehicle 1 described in Item A1, wherein when the single brake indicator 57 is operated, the driving control unit 101a executes control to suppress the rotation speed of the inner wheel if the brake operating device 52 is operated, and does not execute control to suppress the rotation speed of the inner wheel if the brake operating device 52 is not operated.

[0175] With this configuration, as shown in Figure 10A, when the single brake indicator 57 is operated, single braking is performed if the brake operator 52 is also operated, and single braking is not performed if the brake operator 52 is not operated. Therefore, operation of the single brake indicator 57 when the brake operator 52 is not operated can be determined as an incorrect operation. Thus, single braking due to incorrect operation can be prevented.

[0176] (Item A3) The work vehicle 1 as described in Item A1, wherein when the single brake indicator 57 is operated, the driving control unit 101a reduces the rotation speed of the inner wheel to a rotation speed corresponding to a first suppression ratio if the brake operating device 52 is operated, and reduces the rotation speed of the inner wheel to a rotation speed corresponding to a second suppression ratio which is smaller than the first suppression ratio if the brake operating device 52 is not operated.

[0177] With this configuration, as shown in Figure 10B, when the single-sided brake indicator 57 is operated, if the brake operating device 52 is also operated, the rotational speed of the inner wheel is reduced to a rotational speed corresponding to the first suppression ratio, thus enabling strong single-sided braking. On the other hand, if the brake operating device 52 is not operated, the rotational speed of the inner wheel is reduced to a rotational speed corresponding to a second suppression ratio, which is smaller than the first suppression ratio, thus enabling weak single-sided braking. Therefore, single-sided braking When the indicator 57 is operated, one-sided braking can be performed, and strong and weak one-sided braking can be performed appropriately.

[0178] (Item A4) The work vehicle 1 described in Item A1 or A3, wherein when the single brake indicator 57 is operated, the driving control unit 101a controls the rotation speed of the inner wheel to zero or a negative rotation speed if the amount of operation of the brake operating device 52 is greater than or equal to a predetermined value.

[0179] With this configuration, as shown in Figure 10C, when the single brake indicator 57 is operated, the driving control unit 101a controls the rotation speed of the inner wheel to zero or a negative rotation speed if the amount of operation of the brake operating device 52 is greater than or equal to a predetermined value, thereby enabling the driving vehicle body 11 to perform a pivot turn (tight turning) or a spin turn (super-tight turning).

[0180] (Item A5) The work vehicle 1 described in Item A4, wherein when the single brake indicator 57 is operated, the operating amount of the brake operating tool 52 is equal to or greater than the predetermined value and the speed of the vehicle body 11 is equal to or less than the predetermined speed, the running control unit 101a controls the rotation speed of the inner wheel to zero or a negative rotation speed.

[0181] With this configuration, as shown in Figure 10D, when the single brake indicator 57 is operated, if the amount of operation of the brake operating device 52 is greater than or equal to a predetermined value, and the speed of the vehicle body 11 is less than or equal to a predetermined speed, the driving control unit 101a controls the rotation speed of the inner wheel to zero or a negative rotation speed, thereby enabling the vehicle body 11 to perform a pivot turn or spin turn appropriately. In other words, it is possible to prevent the vehicle body 11 from performing a pivot turn or spin turn when its speed exceeds a predetermined speed.

[0182] (Item A6) The work vehicle 1 as described in Item A4, wherein the running control unit 101a prohibits controlling the rotation speed of the inner wheel to zero or a negative rotation speed when the work device 2 connected to the running vehicle body 11 is of the towing type.

[0183] With this configuration, as shown in Figure 10E, it is possible to prevent the vehicle body 11 to which the towing type work device 2 (implement) is connected from performing pivot turns and spin turns.

[0184] (Item A7) The work vehicle 1 described in Item A4, wherein the travel control unit 101a controls the rotation speed of the inner wheel to zero or a negative rotation speed, provided that the weight of the work device 2 connected to the travel vehicle body 11 is less than or equal to a predetermined weight.

[0185] With this configuration, as shown in Figure 10F, when the implement 2 connected to the vehicle body 11 is below a predetermined weight, the vehicle body 11 is made to perform pivot turns and spin turns, thus preventing the field from being damaged by each turn. In other words, the field would be damaged if the vehicle body 11 with an implement 2 exceeding the predetermined weight were made to perform pivot turns and spin turns, so this can be prevented.

[0186] (Item A8) The work vehicle 1 described in Item A4, wherein the driving control unit 101a controls the rotation speed of the inner wheel to zero or a negative rotation speed, provided that the inclination angle of the driving vehicle body 11 is less than or equal to a predetermined inclination angle.

[0187] With this configuration, as shown in Figure 10G, when the inclination angle of the vehicle body 11 is less than or equal to a predetermined inclination angle, the rotation speed of the inner wheel is controlled to zero or a negative rotation speed, thereby enabling the vehicle body 11 to perform a pivot turn or spin turn appropriately.

[0188] (Item A9) The work vehicle 1 according to Item A1, wherein when the single brake indicator 57 is operated, the brake operating device 52 is operated and the work device 2 is not connected to the vehicle body 11, the driving control unit 101a reduces the rotation speed of the inner wheel to a rotation speed corresponding to a first suppression ratio, and when the work device 2 is connected to the vehicle body 11, the rotation speed of the inner wheel is reduced to a rotation speed corresponding to a second suppression ratio which is smaller than the first suppression ratio.

[0189] With this configuration, as shown in Figure 10H, when the single-sided brake indicator 57 is operated, if the brake operating device 52 is also operated and the work device 2 (implement) is not connected, the travel control unit 101a reduces the rotational speed of the inner wheel to a rotational speed corresponding to the first suppression ratio, thus enabling strong single-sided braking. If the work device 2 is connected, the travel control unit 101a reduces the rotational speed of the inner wheel to a rotational speed corresponding to the second suppression ratio, which is smaller than the first suppression ratio, thus enabling weak single-sided braking. Therefore, strong single-sided braking can be applied when the work device 2 is not connected, and weak single-sided braking can be applied when the work device 2 is connected. Thus, appropriate single-sided braking can be applied depending on whether the work device 2 is connected or not.

[0190] (Item A10) The running control unit 101a, when the single brake indicator 57 is operated and the brake operating device 52 is operated, reduces the rotation speed of the inner wheel to a rotation speed corresponding to a first suppression ratio if the work device 2 connected to the running vehicle body 11 is of a direct-mount type, and reduces the rotation speed of the inner wheel to a rotation speed corresponding to a second suppression ratio which is smaller than the first suppression ratio if the work device 2 is of a tow type, as described in Item A1.

[0191] With this configuration, as shown in Figure 10I, when the single-sided brake indicator 57 is operated, and the brake operating device 52 is also operated, the driving control unit 101a reduces the rotational speed of the inner wheel to a rotational speed corresponding to the first suppression ratio if the work device 2 (implement) connected to the driving vehicle body 11 is a direct-mount type, thereby enabling strong single-sided braking. If the work device 2 is a towed type (e.g., a trailer), the driving control unit 101a reduces the rotational speed of the inner wheel to a rotational speed corresponding to a second suppression ratio, which is smaller than the first suppression ratio, thereby enabling weak single-sided braking. Therefore, if the work device 2 is a direct-mount type, strong single-sided braking can be applied, and if the work device 2 is a towed (trailer) type, weak single-sided braking can be applied. Thus, appropriate single-sided braking can be applied depending on whether the work device 2 is a direct-mount type or a towed (trailer) type.

[0192] (Item A11) The work vehicle 1 according to Item A1, wherein when the single brake indicator 57 is operated, the driving control unit 101a controls the electric motor 34 corresponding to the front inner wheel to suppress the rotation speed of the front inner wheel when the brake operating device 52 is operated and the work device 2 is connected to the front of the driving vehicle body 11, and controls the electric motor 34 corresponding to the rear inner wheel to suppress the rotation speed of the rear inner wheel when the work device 2 is connected to the rear of the driving vehicle body 11 or when the work device 2 is not connected to the driving vehicle body 11.

[0193] According to this configuration, as shown in Figure 10J, when the single brake indicator 57 is operated, and the brake operating device 52 is also operated, and the working device 2 is connected to the front of the vehicle body 11, the center of gravity of the vehicle body 11 including the front working device 2 becomes more forward, so as shown on the right side of Figure 17, the rotation speed of the front inner wheel is suppressed. When the working device 2 is connected to the rear of the vehicle body 11 or when the working device 2 is not connected, the center of gravity of the vehicle body 11 including the rear working device 2 becomes more rearward, and when the center of gravity of the vehicle body 11 without the working device 2 becomes more rearward, as shown on the left side of Figure 17. This suppresses the rotation speed of the rear inner wheel. Therefore, even if the center of gravity of the entire vehicle body 11 changes forward or backward due to the connection of the working device 2 to the front or rear, the single-sided brake can be properly applied.

[0194] (Item A12) The work vehicle 1 according to Item A11, wherein when the work device 2 is connected to the front of the vehicle body 11, the driving control unit 101a reduces the rotational speed of the front inner wheel to a rotational speed corresponding to a first suppression ratio, and reduces the rotational speed of the rear inner wheel to a rotational speed corresponding to a second suppression ratio which is smaller than the first suppression ratio.

[0195] With this configuration, as shown in Figure 10K, when the work device 2 is connected to the front of the vehicle body 11, the rotational speed of the front inner wheel is reduced to a rotational speed corresponding to the first suppression ratio, thus enabling strong single-sided braking, and the rotational speed of the rear inner wheel is reduced to a rotational speed corresponding to the second suppression ratio, which is smaller than the first suppression ratio, thus enabling weak single-sided braking. In other words, in the case of front-side impulse, the center of gravity of the vehicle body 11 is closer to the front, so the front inner wheel, which is closer to the center of gravity, can be subjected to strong single-sided braking, and the rear inner wheel can be subjected to weak single-sided braking. For this reason, in the case of front-side impulse, the vehicle body 11 can be rotated with the front inner wheel, which is closer to the center of gravity, as the pivot point.

[0196] (Item A13) The work vehicle 1 according to Item A11, wherein the travel control unit 101a reduces the rotational speed of the rear inner wheel to a rotational speed corresponding to a first suppression ratio, and reduces the rotational speed of the front inner wheel to a rotational speed corresponding to a second suppression ratio which is smaller than the first suppression ratio, when the work device 2 is connected to the rear of the travel vehicle body 11 or when the work device 2 is not connected to the travel vehicle body 11.

[0197] With this configuration, as shown in Figure 10K, when the work device 2 is connected to the rear of the vehicle body 11, or when the work device 2 is not connected to the vehicle body 11, the rotational speed of the rear inner wheel is reduced to a rotational speed corresponding to the first suppression ratio, thereby enabling strong single-sided braking. Conversely, the rotational speed of the front inner wheel is reduced to a rotational speed corresponding to a second suppression ratio, which is smaller than the first suppression ratio, thereby enabling weak single-sided braking. In other words, in the case of rear impulse or without impulse, the center of gravity of the vehicle body 11 is closer to the rear, so the rear inner wheel, which is closer to the center of gravity, can be subjected to strong single-sided braking, and the front inner wheel can be subjected to weak single-sided braking. For this reason, the vehicle body 11 can be rotated with the rear inner wheel, which is closer to the center of gravity, as the pivot point, in the case of rear impulse or without impulse.

[0198] (Item A14) The brake operating device 52 is a single operating device as described in any one of items A1 to A13 of the work vehicle 1.

[0199] This configuration allows for proper single-wheel braking in a work vehicle 1 having a single brake operating device 52, unlike conventional work vehicles that have a two-piece brake pedal system (i.e., a left brake pedal and a right brake pedal) for independently braking the left and right wheels.

[0200] (Item A15) A work vehicle 1 comprising: a running body 11; a power unit 31 having electric motors 34 that drive each wheel 22 provided on the left and right sides of the running body 11; a steering device 41 that steers the running body 11 based on the operation of a steering control device 42; an input unit 57A that receives an operation input for suppressing the rotation speed of an inner wheel located in the steering direction of the steering control device 42; and a running control unit 101a, wherein the running control unit 101a controls the electric motor 34 corresponding to the inner wheel to suppress the rotation speed of the inner wheel when an operation input is received from the input unit 57A while braking force is applied to both wheels by brake operation.

[0201] With this configuration, when both wheels are braking during steering, it is possible to appropriately determine whether or not to apply single-sided braking based on the operation input of the input unit 57A. Furthermore, when there is an operation input to the input unit 57A while both wheels are braking during steering, the inner wheel (the inner wheel located in the steering direction by the steering control device 42) can be braked even more strongly. In other words, single-sided braking can be appropriately applied. Therefore, it is possible to appropriately determine whether or not to apply single-sided braking, and to appropriately apply single-sided braking.

[0202] Although the present invention has been described above, 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 rather than by the foregoing description, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of Symbols]

[0203] 1: Work vehicles 2: Working equipment 11: Vehicle body 31: Power plant 22 :Wheel 34: Electric motor 41: Steering gear 42: Steering controls 52: Brake operating device 57: Single brake indicator 57A: Input section 101a: Driving control unit

Claims

1. The vehicle body and A power unit having electric motors that drive each wheel, located on the left and right sides of the vehicle body, Brake operating device, A single brake indicator, A steering device that steers the vehicle body based on the operation of a steering control device, It comprises a driving control unit, A work vehicle, wherein the driving control unit controls the electric motor corresponding to the inner wheel to suppress the rotation speed of the inner wheel located in the steering direction of the steering control device, based on whether or not the brake control device is being operated when the single brake indicator is operated.

2. The work vehicle according to claim 1, wherein the driving control unit, when the single brake indicator is operated, executes control to suppress the rotation speed of the inner wheel if the brake operating device is operated, and does not execute control to suppress the rotation speed of the inner wheel if the brake operating device is not operated.

3. The work vehicle according to claim 1, wherein the driving control unit, when the single brake indicator is operated, reduces the rotational speed of the inner wheel to a rotational speed corresponding to a first suppression ratio if the brake operating device is operated, and reduces the rotational speed of the inner wheel to a rotational speed corresponding to a second suppression ratio smaller than the first suppression ratio if the brake operating device is not operated.

4. The work vehicle according to claim 1, wherein the driving control unit controls the rotation speed of the inner wheel to zero or a negative rotation speed when the single brake indicator is operated and the amount of operation of the brake operating device is greater than or equal to a predetermined value.

5. The work vehicle according to claim 4, wherein the driving control unit controls the rotation speed of the inner wheel to zero or a negative rotation speed when the single brake indicator is operated and the amount of operation of the brake operating device is equal to or greater than the predetermined value and the speed of the driving vehicle is equal to or less than the predetermined speed.

6. The work vehicle according to claim 4, wherein the running control unit prohibits controlling the rotation speed of the inner wheel to zero or a negative rotation speed when the work device connected to the running vehicle body is of the towing type.

7. The work vehicle according to claim 4, wherein the driving control unit controls the rotation speed of the inner wheel to zero or a negative rotation speed, provided that the weight of the work device connected to the driving vehicle body is less than or equal to a predetermined weight.

8. The work vehicle according to claim 4, wherein the driving control unit controls the rotation speed of the inner wheel to zero or a negative rotation speed on the condition that the inclination angle of the driving vehicle body is less than or equal to a predetermined inclination angle.

9. The work vehicle according to claim 1, wherein the running control unit reduces the rotational speed of the inner wheel to a rotational speed corresponding to a first suppression ratio when the single brake indicator is operated and the brake operating device is operated and no work device is connected to the running vehicle body, and reduces the rotational speed of the inner wheel to a rotational speed corresponding to a second suppression ratio smaller than the first suppression ratio when a work device is connected to the running vehicle body.

10. When the single brake indicator is operated, the running control unit, if the brake operating device is operated and the working device connected to the running vehicle body is of the direct-mount type, reduces the rotation speed of the inner wheel to a rotation speed corresponding to the first suppression ratio, and the working device is of the towing type In the case of the P, the work vehicle according to claim 1, wherein the rotational speed of the inner ring is reduced to a rotational speed corresponding to a second suppression ratio that is smaller than the first suppression ratio.

11. The work vehicle according to claim 1, wherein the driving control unit controls the electric motor corresponding to the front inner wheel to suppress the rotation speed of the front inner wheel when the single brake indicator is operated and the brake operating device is operated and the work device is connected to the front of the vehicle body, and controls the electric motor corresponding to the rear inner wheel to suppress the rotation speed of the rear inner wheel when the work device is connected to the rear of the vehicle body or when the work device is not connected to the vehicle body.

12. The work vehicle according to claim 11, wherein, when the work device is connected to the front of the vehicle body, the driving control unit reduces the rotational speed of the front inner wheel to a rotational speed corresponding to a first suppression ratio, and reduces the rotational speed of the rear inner wheel to a rotational speed corresponding to a second suppression ratio smaller than the first suppression ratio.

13. The work vehicle according to claim 11, wherein the travel control unit reduces the rotational speed of the rear inner wheel to a rotational speed corresponding to a first suppression ratio, and reduces the rotational speed of the front inner wheel to a rotational speed corresponding to a second suppression ratio that is smaller than the first suppression ratio, when the work device is connected to the rear of the travel vehicle body or when the work device is not connected to the travel vehicle body.

14. The work vehicle according to any one of claims 1 to 13, wherein the brake operating device is a single operating device.

15. The vehicle body and A power unit having electric motors that drive each wheel, located on the left and right sides of the vehicle body, A steering device that steers the vehicle body based on the operation of a steering control device, An input unit that receives an input for controlling the rotation speed of the inner ring located in the steering direction of the steering control device, It comprises a driving control unit, The aforementioned driving control unit controls the electric motor corresponding to the inner wheel to suppress the rotation speed of the inner wheel when an operation input is received from the input unit while braking force is applied to both wheels by brake operation, in a work vehicle.

Images