Work vehicle

Abstract

The present invention prevents a reduction in work efficiency between interruption and reinstatement of automatic excavation. A work vehicle (100) comprises: a vehicle body (100A,B) that has a travel wheel (19); a front work device (102); a travel direction switching device (5) that switches the travel direction of the vehicle body; and a controller (9) that automatically controls the front work device when a start condition has been met in an automatic excavation mode. When the controller is automatically controlling the front work device and an interruption condition for interrupting the automatic excavation mode is met, the controller interrupts the automatic excavation mode to suspend the automatic control of the front work device. When the controller has interrupted the automatic excavation mode and a reinstatement condition for reinstating the interrupted automatic excavation mode is met, the controller reinstates the automatic excavation mode. The start condition includes the travel direction switching device being in a position that indicates forward travel, and the reinstatement condition is the travel direction switching device being in a position that indicates neutrality or backward movement.

Description

Work vehicle

[0001] The present invention relates to a work vehicle such as a wheel loader.

[0002] In recent years, work vehicles that automatically excavate an excavation target have been known. For example, the wheel loader described in Patent Document 1 starts automatic excavation by operating an automatic excavation start switch.

[0003] International Publication No. 2015-004809

[0004] In the conventional technique described in Patent Document 1, one of the conditions for automatic excavation is that the wheel loader is moving forward and the bucket is in contact with the ground. Therefore, when an operator accidentally starts automatic excavation or when it is desired to redo excavation, once automatic excavation is interrupted, it is necessary to bring the bucket into contact with the ground again to resume automatic excavation. Therefore, improvement of work efficiency has been an issue to be solved in the above-mentioned conventional technique.

[0005] An object of the present invention is to provide a work vehicle that can prevent a decrease in work efficiency from the interruption of automatic excavation to the resumption thereof.

[0006] In order to achieve the above object, one aspect of the present invention provides a work vehicle including: a vehicle body having traveling wheels; a front work device attached to a front portion of the vehicle body; a traveling direction switching device that switches a traveling direction of the vehicle body; and a controller that automatically controls the front work device when a start condition is satisfied during an automatic excavation mode, wherein the controller interrupts the automatic excavation mode and stops automatic control of the front work device being executed when an interruption condition for interrupting the automatic excavation mode is satisfied during automatic control of the front work device, resumes the interrupted automatic excavation mode when a resumption condition for resuming the interrupted automatic excavation mode is satisfied during interruption of the automatic excavation mode, the start condition includes that the traveling direction switching device is at a position instructing forward travel, and the resumption condition is that the traveling direction switching device is at a position instructing neutral or reverse travel.

[0007] According to the present invention, it is possible to provide a work vehicle that can prevent a decrease in work efficiency from the interruption of automatic excavation to its resumption. Other problems, configurations, and effects will be clarified by the following description of the embodiments.

[0008] This is a side view of a wheel loader according to an embodiment of the present invention. This is a block diagram showing the internal configuration of the wheel loader. This is a diagram showing an example of the interior of the driver's cab. This is a diagram showing the transition of control modes of the wheel loader. This is a diagram showing the excavation posture of the wheel loader. This is a flowchart showing the control procedure for excavation work.

[0009] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Figure 1 is a side view of a wheel loader (work vehicle) 100 according to an embodiment of the present invention.

[0010] The wheel loader 100 is an articulated work vehicle that is steered by bending its body in the middle near its center. The front frame 100A, which is the front part of the body, and the rear frame 100B, which is the rear part of the body, are connected by a center joint 103 so as to be rotatable in the left-right direction, and the front frame 100A bends in the left-right direction relative to the rear frame 100B.

[0011] The vehicle body is equipped with four wheels (running wheels) 19. Two of the wheels 19 are front wheels 19A, located on the left and right sides of the front frame 100A, and the remaining two wheels 19 are rear wheels 19B, located on the left and right sides of the rear frame 100B. Note that in Figure 1, only the front wheels 19A and rear wheels 19B located on the left side are shown.

[0012] A hydraulically driven front work device 102 is attached to the front of the front frame 100A for performing cargo handling operations, such as excavating soil, sand, or minerals and loading them onto dump trucks or hoppers.

[0013] The rear frame 100B is provided with a driver's cab 112 where the operator sits, a machine room 113 that houses the equipment necessary for driving the wheel loader 100, and a counterweight 114 that maintains balance with the front working device 102 to prevent the vehicle body from tilting. In the rear frame 100B, the driver's cab 112 is located at the front, the counterweight 114 is located at the rear, and the machine room 113 is located between the driver's cab 112 and the counterweight 114.

[0014] The front work device 102 includes a lift arm 121 that is rotatably mounted vertically to the front frame 100A, a pair of left and right lift arm cylinders 16 that act as hydraulic cylinders to drive the lift arm 121, a bucket 123 that is rotatably mounted vertically to the tip of the lift arm 121, a bucket cylinder 17 that acts as a hydraulic cylinder to drive the bucket 123, and a bell crank 125 that is rotatably connected to the lift arm 121 and forms a link mechanism between the bucket 123 and the bucket cylinder 17.

[0015] The lift arm 121 rotates upward relative to the front frame 100A as the rods of the pair of lift arm cylinders 16 extend, and rotates downward relative to the front frame 100A as the rods of the pair of lift arm cylinders 16 retract.

[0016] The bucket 123 rotates upward relative to the lift arm 121 and tilts backward toward the front frame 100A (vehicle body) when the rod of the bucket cylinder 17 extends (tilt operation), and rotates downward relative to the lift arm 121 and tilts forward when the rod of the bucket cylinder 17 retracts (dump operation). As a result, the bucket 123 can scoop up and discharge (dump) the work material such as soil and minerals.

[0017] Furthermore, the bucket 123 can be replaced with various attachments such as blades, and the wheel loader 100 can perform various tasks such as snow removal and soil pushing in addition to cargo handling using the bucket 123.

[0018] This wheel loader 100 can be operated manually by an operator in the cab 112, as well as by an automated excavation operation as described later. Alternatively, the wheel loader 100 may be operated remotely by an operator located some distance away.

[0019] Next, the internal configuration of the wheel loader 100 will be described. Figure 2 is a block diagram showing the internal configuration of the wheel loader 100. In Figure 2, solid lines represent lines through which hydraulic fluid flows, and dotted lines represent electrical signal lines.

[0020] As shown in Figure 2, the wheel loader 100 is equipped with a controller 9 that controls the entire vehicle body. The controller 9 is located, for example, in the driver's cab 112. The controller 9 has a configuration in which a CPU, RAM, ROM, HDD, input I / F, and output I / F are connected to each other via a bus. In this hardware configuration, the CPU reads the calculation program (software) stored in a recording medium such as ROM, HDD, or optical disc, expands it onto RAM, and executes the expanded calculation program. The calculation program and hardware work together to realize the functions of the controller 9.

[0021] The controller 9's input interface is electrically connected to the following: the work equipment lever 1, the accelerator pedal 2, the parking switch 3, the activation switch 4, the forward / reverse lever 5, the lift cylinder pressure sensor 6, the lift arm angle sensor 7, the bucket angle sensor 8, the brake pressure sensor 12, and the vehicle speed sensor 21.

[0022] The work equipment lever (operating device) 1 is a component for operating the front work equipment 102, and is composed of, for example, an arm operating lever and a bucket operating lever. The accelerator pedal 2 adjusts the rotational speed of the engine 13 according to the amount it is pressed. The parking switch 3 activates and deactivates the parking brake device (not shown). The parking brake device brakes the propeller shaft when the parking switch 3 is operated.

[0023] The activation switch 4 is a switch for activating the automatic excavation mode, which will be described later. The forward / reverse lever (travel direction switching device) 5 is a component for switching the travel direction of the wheel loader 100 to forward (F), neutral (N), or reverse (R). The forward / reverse lever 5 can be switched to a position that indicates forward (F), neutral (N), or reverse (R) (forward position, neutral position, reverse position). When the forward / reverse lever 5 is in the neutral position, the wheel loader 100 is unable to move under its own power.

[0024] The lift cylinder pressure sensor 6 detects the bottom pressure of the lift arm cylinder 16. The lift arm angle sensor 7 detects the angle of the lift arm 121. The bucket angle sensor 8 detects the angle of the bucket cylinder 17. The brake pressure sensor 12 detects the pressure of the hydraulic fluid supplied to the brake (brake device) 20. The vehicle speed sensor 21 detects the rotational speed of the propeller shaft. The vehicle speed of the wheel loader 100 is calculated from the rotational speed of the propeller shaft.

[0025] The output interface of the controller 9 is electrically connected to the engine 13, the control valve 15, and the display panel 26.

[0026] The driving force from the engine 13 mounted on the wheel loader 100 is reduced by the transmission 14 and transmitted to the front and rear axles 18 via a propeller shaft (not shown). The driving force transmitted to the axles 18 is then transmitted to the left and right wheels 19 (19A, 19B), which are the running gear, via a differential and final reduction gear (not shown) within the axles 18, causing the wheel loader 100 to move.

[0027] The wheel loader 100 also includes a hydraulic pump 22 for supplying hydraulic fluid and a hydraulic fluid tank (not shown) for storing the hydraulic fluid. The hydraulic pump 22 is driven by the engine 13, and the hydraulic fluid supplied from the hydraulic pump 22 operates the front working device 102 (lift arm cylinder 16, bucket cylinder 17).

[0028] The control valve 15 switches the oil passages to the lift arm cylinder 16 and bucket cylinder 17 in response to operation signals from the work equipment levers 1 (arm operation lever, bucket operation lever) located in the driver's cab 112 of the wheel loader 100, thereby causing the lift arm cylinder 16 and bucket cylinder 17 to extend and retract according to the operator's instructions.

[0029] Furthermore, the wheel loader 100 brakes the wheels 19 with a brake 20. The brake 20 is, for example, a wet disc brake. The brake 20 is housed in the case of the axle 18. When hydraulic fluid is supplied to the brake 20 via the brake valve 11, the brake 20 generates a braking force corresponding to the pressure of the hydraulic fluid. The wheel loader 100 is equipped with a hydraulic source (not shown) that supplies hydraulic fluid to the brake 20. The hydraulic source is a pressure source with a pressure lower than the discharge pressure of the hydraulic pump 22, and is, for example, composed of an accumulator that stores hydraulic fluid that has been depressurized from the hydraulic pump 22.

[0030] The brake valve 11 is a pressure reducing valve that reduces the hydraulic fluid supplied from the hydraulic source to a pressure corresponding to the compression force of the spring. When the operator presses down on the brake pedal 10, the brake valve 11 reduces the pressure of the hydraulic fluid supplied from the hydraulic source to a pressure corresponding to the pressing force (amount of pressing) of the brake pedal 10. The brake valve 11 reduces the pressure of the hydraulic fluid so that the higher the compression force of the spring, that is, the greater the pressing force of the brake pedal 10, the higher the pressure of the hydraulic fluid supplied to the brake 20.

[0031] Next, the internal configuration of the driver's cab 112 will be described. Figure 3 shows an example of the interior of the driver's cab 112.

[0032] As shown in Figure 3, the driver's cab 112 is equipped with a work equipment lever 1, a steering wheel 25 for steering operations, an accelerator pedal 2, a brake pedal 10, a parking switch 3, an activation switch 4, a forward / reverse lever 5, and a display panel 26.

[0033] The steering wheel 25 is used to steer the wheel loader 100. The display panel 26 displays the travel speed of the wheel loader 100 detected by the vehicle speed sensor 21. The display panel 26 also displays the current control mode. Specifically, it shows whether the system is in normal digging mode 51, automatic digging mode 52, or automatic digging mode interrupted 53 (see Figure 4).

[0034] Next, the control modes of the wheel loader 100 will be described. Figure 4 is a diagram showing the transitions between the control modes of the wheel loader 100. As shown in Figure 4, the controller 9 switches the control mode of the wheel loader 100 between normal excavation mode 51, automatic excavation mode 52, and automatic excavation mode interrupted 53.

[0035] The normal drilling mode 51 is a control mode that allows manual drilling by the operator. In normal drilling mode 51, the operator can operate the work equipment lever 1 to perform drilling work with the front work device 102. In other words, in normal drilling mode 51, automatic drilling is disabled. On the other hand, the automatic drilling mode 52 is a control mode that allows automatic drilling work (automatic drilling operation) with the front work device 102. Switching between normal drilling mode 51 and automatic drilling mode 52 is done by turning the activation switch 4 on or off.

[0036] In the normal drilling mode 51, when the activation switch 4 is turned on, the controller 9 switches the control mode to the automatic drilling mode 52. In this embodiment, in order to avoid unexpected situations, the activation switch 4 is only accepted when the forward / reverse lever 5 is in the neutral position. Of course, it is also possible to configure the system to accept operation of the activation switch 4 regardless of the position of the forward / reverse lever 5.

[0037] In automatic drilling mode 52, the control state first becomes "determining automatic drilling start" 52A. "Determining automatic drilling start" 52A is a state where the system waits until the conditions for starting automatic drilling (described later) are met. When the conditions for starting automatic drilling are met in "determining automatic drilling start" 52A, the controller 9 switches the control state to "controlling automatic drilling" 52B and performs automatic drilling, which is the automatic control of the front work device 102.

[0038] Furthermore, when the conditions for ending automatic drilling (described later) are met during automatic drilling control 52B, the controller 9 terminates the automatic drilling by the front work device 102 and transitions the control state to automatic drilling start determination 52A.

[0039] Furthermore, during automatic drilling control 52B, if the conditions for interrupting automatic drilling (described later) are met, the controller 9 will stop (interrupt) the automatic drilling by the front work device 102 and transition the control state to automatic drilling mode interrupted 53.

[0040] Then, while the automatic drilling mode is suspended 53, if the conditions for returning to automatic drilling (described later) are met, the controller 9 will transition (return) to the automatic drilling start determination state 52A and wait until the conditions for disclosing automatic drilling are met.

[0041] Here, the start condition, interruption condition, return condition, and termination condition are as follows:

[0042] Starting conditions: All of the following conditions in the <State Conditions> and <Entry Conditions> must be met. <State Conditions> (11) The bucket angle detected by the bucket angle sensor 8 is within a predetermined angle range (for example, ±10 degrees or less), and the bucket height calculated from the lift arm angle sensor 7 is below a predetermined height position. That is, the bucket 123 is in the digging position (see digging positions 1 and 2 in Figure 5). (12) The forward / reverse lever 5 is in the forward position, the accelerator pedal 2 is depressed, and the brake pedal 10 is not operated. (13) The vehicle speed of the wheel loader 100 detected by the vehicle speed sensor 21 is below a predetermined speed (for example, 10 km / h). (14) The work equipment lever 1 is not operated.

[0043] <Entry Conditions> (21) The accelerator pedal 2 is depressed, and the vehicle body is decelerating. (22) The bottom pressure of the lift arm cylinder 16 detected by the lift cylinder pressure sensor 6 is equal to or higher than a threshold value. (23) The traction force is equal to or lower than a threshold value. Here, the traction force is calculated based on the engine speed, the speed ratio / gear ratio of the transmission 14, the diameter of the wheels 19 (tire diameter), and the inertia force (vehicle weight / acceleration / deceleration). Specifically, the engine speed is converted into the speed transmitted to the wheels 19 by the speed ratio and the gear ratio. The forward force of the vehicle body is calculated from the rotation speed of the wheels 19 and the tire diameter. The inertia force is calculated from the vehicle weight and the acceleration (deceleration), and the difference between the inertia force and the aforementioned forward force is calculated to obtain the traction force. Then, when the traction force becomes equal to or lower than a predetermined threshold value, the controller 9 determines that the wheel loader 100 (the bucket 123) is in contact with a pile.

[0044] Interruption conditions: At least any one of the following conditions is satisfied. (31) The work equipment lever 1 is operated. (32) The brake pedal 10 is depressed (the brake 20 is activated). (33) The forward / reverse lever 5 is not in a forward position (that is, it is in a neutral position or a reverse position).

[0045] Restoration conditions: (41) The forward / reverse lever 5 is not in a forward position (that is, it is in a neutral position or a reverse position).

[0046] Termination conditions: At least any one of the following conditions is satisfied. (51) The enabling switch 4 is turned off. (52) The bucket 123 is not in an excavation posture.

[0047] Next, the automatic excavation control performed by the controller 9 will be described. Figure 6 is a flowchart showing the control procedure of excavation work by the controller 9.

[0048] When, for example, a key switch of an engine 13 is turned on, the controller 9 starts the process shown in FIG. 6. Once the process is started, in step S1, the controller 9 determines whether automatic excavation is enabled (whether the enabling switch 4 is turned on, and whether the system is in the automatic excavation mode). If automatic excavation is enabled (S1 / YES), the controller 9 proceeds to step S2, and determines whether the start condition for automatic excavation is satisfied (whether automatic excavation is to be started) (during automatic excavation start determination 52A / FIG. 4). On the other hand, if automatic excavation is not enabled (S1 / NO), the controller 9 waits in step S1 until automatic excavation becomes enabled.

[0049] Next, if the start condition for automatic excavation is satisfied (S2 / YES), the controller 9 proceeds to step S3, and determines whether an interruption condition is satisfied (whether an interruption operation has been performed). On the other hand, if the start condition for automatic excavation is not satisfied (S2 / NO), the controller 9 waits in step S2 until the start condition is satisfied.

[0050] Next, if the interruption condition is not satisfied (S3 / NO), the controller 9 proceeds to step S4, and executes automatic excavation for automatically controlling the front working device 102 (during automatic excavation control 52B / FIG. 4). Then, the controller 9 proceeds to step S5, and determines whether an end condition is satisfied (whether automatic excavation has been completed). If automatic excavation has been completed (S5 / YES), the process returns to step S2 (during automatic excavation start determination 52A / FIG. 4). On the other hand, if automatic excavation has not been completed (S5 / NO), the process returns to step S3.

[0051] Furthermore, if the interruption condition is met in step S3 (S3 / YES), the controller 9 proceeds to step S6 and stops (interrupts) automatic drilling (automatic drilling mode interrupted 53 / Figure 4). Then, the controller 9 proceeds to step S7 and determines whether or not the recovery condition has been met (whether or not a recovery operation has been performed). If the recovery condition has been met (S7 / YES), the controller 9 returns to step S2 and waits until the start condition is met (automatic drilling start determination in progress 52A / Figure 4). Specifically, the controller 9 determines whether or not the forward / reverse lever 5 has been switched to a position other than forward (neutral or reverse), and if it has been switched to a position other than forward, it determines that a recovery operation has been performed and returns to step S2.

[0052] On the other hand, if the recovery condition is not met (S7 / NO), that is, if the forward / reverse lever 5 is in the forward position, the controller 9 waits until the recovery condition is met.

[0053] According to this processing procedure, when the return conditions are met (the return operation is performed), the front work device 102 can transition (return) to a state where it is waiting to start automatic excavation (during automatic excavation start determination 52A), with the posture of the front work device 102 remaining the same as when automatic excavation was interrupted. Therefore, as in the conventional method, it is not necessary to return the bucket 123 to its initial position where it touches the ground, thus saving the time required for that return operation. This improves work efficiency.

[0054] As described above, this embodiment can achieve the following effects.

[0055] Automatic excavation (during automatic excavation control 52B / Figure 4) begins when the start conditions, including the forward / reverse lever 5 being switched to the forward position, are met. However, if the operator wants to restart the automatic excavation for reasons such as adjusting the position of the front work device 102 and the excavation target (ground), they would interrupt the automatic excavation and switch the forward / reverse lever 5 to reverse in order to move the vehicle in reverse. In this embodiment, when automatic excavation is interrupted (automatic excavation mode interrupted 53), the system returns from automatic excavation mode interrupted 53 to automatic excavation mode 52 (automatic excavation start determination 52A) when the forward / reverse lever 5 is switched to reverse. By doing this, the operator's operation (switching the forward / reverse lever 5 to reverse after interrupting automatic excavation) and the transition of the control mode are linked, thus preventing a decrease in work efficiency from the interruption to the resumption of automatic excavation.

[0056] Furthermore, it becomes possible to operate the system in a way that aligns with the operator's intention to restart the automatic drilling, improving usability. In addition, if automatic drilling starts at a time unintended by the operator, the system can be interrupted (automatic drilling mode interrupted 53), and then the forward / reverse lever 5 can be switched to neutral or reverse to return from automatic drilling mode interrupted 53 to automatic drilling mode 52 (automatic drilling start determination in progress 52A). Therefore, the operator can return from automatic drilling mode interrupted 53 to automatic drilling mode 52 and resume automatic drilling at any time of their choosing.

[0057] Furthermore, if the forward / reverse lever 5 is switched from the forward position to the neutral or reverse position during automatic excavation, the interruption condition is met, and automatic excavation by the front work device 102 is interrupted. However, the recovery condition is also met at the same time, so the system immediately returns from the "automatic excavation mode interrupted" state 53 to the "automatic excavation start determination" state 52A. Therefore, if the operator wants to restart automatic excavation, they can interrupt the automatic excavation by switching the forward / reverse lever 5 to the neutral or reverse position, and then quickly resume automatic excavation by the front work device 102 by switching the forward / reverse lever 5 back to the forward position.

[0058] For example, by switching the forward / reverse lever 5 from the forward position to the reverse position to interrupt automatic excavation, and simultaneously returning to automatic excavation mode, the vehicle can be reversed to adjust its position relative to the excavation target, and then by switching the forward / reverse lever 5 from the reverse position to the forward position, automatic excavation can be quickly restarted. Therefore, interruption and restart of automatic excavation can be achieved with a series of operations on the forward / reverse lever 5. Thus, work efficiency is improved.

[0059] Furthermore, after interrupting automatic excavation by operating the work equipment lever 1 or pressing the brake pedal 10, the system can be returned to automatic excavation mode 52 from the interrupted automatic excavation mode 53 by switching the forward / reverse lever 5 to the neutral or reverse position, thereby enabling smooth automatic excavation work.

[0060] Furthermore, since the system is configured to start automatic excavation only when the height of the bucket 123 is below a predetermined height, automatic excavation can be started without touching the bucket to the ground, as in conventional systems. Also, by not allowing automatic excavation if the height of the bucket 123 exceeds the predetermined height, it is possible to prevent automatic excavation from being performed with the bucket 123 in an unsuitable position for automatic excavation. In other words, it is possible to avoid automatic excavation being performed when the bucket 123 is not in an excavation position.

[0061] Furthermore, by setting the angle of the bucket 123 to be within a predetermined angle as a condition for starting automatic excavation, it is possible to prevent automatic excavation from being performed while the bucket 123 is tilted too much. In other words, it is possible to avoid automatic excavation being performed when the bucket 123 is not in the correct excavation position.

[0062] Furthermore, by setting the vehicle speed of the wheel loader 100 to be low (below a predetermined speed) as a condition for starting automatic excavation, the risk of automatic excavation starting at a time unintended by the operator can be reduced.

[0063] In the above embodiment, the starting condition was defined as all of the state conditions (11) to (14) and the entry conditions (21) to (23) being met. However, the starting condition may also be defined as any one or more combinations of the state conditions being met, or any one or more combinations of the entry conditions being met. Furthermore, it is also acceptable for only some of the conditions to be met. For example, among the state conditions (12), at least the forward / reverse lever 5 being switched to the forward position may be defined as the starting condition being met. Also, regarding the interruption conditions (31) to (33) and the termination conditions (51) to (52), it was defined as any one of the conditions being met, but it is also acceptable for all of the conditions to be met.

[0064] 1. Work equipment lever (operating device) 5. Forward / reverse lever (travel direction switching device) 7. Lift arm angle sensor (attitude sensor) 8. Bucket angle sensor (attitude sensor) 9. Controller 19. Wheels (traveling wheels) 20. Brake (brake device) 21. Vehicle speed sensor 100. Wheel loader (work vehicle) 100A. Front frame (vehicle body) 100B. Rear frame (vehicle body) 102. Front work equipment 121. Lift arm 123. Bucket

Claims

1. A work vehicle comprising: a vehicle body having wheels; a front work device attached to the front of the vehicle body; a travel direction switching device for switching the travel direction of the vehicle body; and a controller for automatically controlling the front work device when a start condition is met during an automatic digging mode, wherein the controller interrupts the automatic digging mode and stops the automatic control of the front work device while it is automatically controlling the front work device when an interruption condition for interrupting the automatic digging mode is met; and resumes the automatic digging mode when a resume condition for resuming the interrupted automatic digging mode is met during the interruption of the automatic digging mode, the start condition includes the travel direction switching device being in a position that indicates forward movement, and the resume condition is that the travel direction switching device is in a position that indicates neutral or reverse movement.

2. A work vehicle according to claim 1, characterized in that the interruption condition includes the travel direction switching device being in a position indicating neutral or reverse.

3. A work vehicle according to claim 1, comprising: an operating device for operating the front work device; and a braking device for applying braking to the movement of the vehicle body, wherein the interruption condition includes the operation of the operating device or the activation of the braking device.

4. A work vehicle according to claim 1, wherein the front work device includes a bucket, and is equipped with a posture sensor for detecting the posture of the front work device, and the start condition further includes that the height of the bucket detected by the posture sensor is less than or equal to a predetermined height.

5. A work vehicle according to claim 4, wherein the starting condition further includes that the angle of the bucket detected by the attitude sensor is within a predetermined angular range.

6. A work vehicle according to claim 1, wherein it is equipped with a vehicle speed sensor for detecting the speed of the vehicle body, and the start condition further includes that the speed of the vehicle body detected by the vehicle speed sensor is less than or equal to a predetermined speed.

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