Work vehicle

Abstract

To provide a work vehicle that can make operator's work easy and suppress increase in the number of switches, etc. around an operator's seat.SOLUTION: A work vehicle includes a travelling machine body, a farm field work device supported on the travelling machine body so as to be lifted and lowered for performing work for a farm field, a state changing part capable of changing the state of the farm field work device over a work state and a non-work state, a travelling detection part for detecting a travelling state of the travelling machine body, a non-work state switching control part for performing change control for the state changing part to change the farm field work device to the non-work state when the travelling detection part detects shift from reciprocating travelling to turning travelling, a work state switching control part for performing change control for the state changing part to change the farm field work device to the work state when the travelling detection part detects the shift from turning travelling to reciprocating travelling, and an operation part S configured to operate the non-work state switching control part and the work state switching control part to an effective state and an invalid state with a single operation device 18.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to a work vehicle having a work device that can be raised and lowered at the rear end of a vehicle body.

Background Art

[0002] Taking a tractor as an example, Patent Document 1 describes a tractor in which a work device automatically rises when the steering wheel is turned significantly.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Such a tractor may have not only a function of automatically raising the work device but also, for example, a function of automatically lowering the work device. If switches or the like are arranged for each function, the number of switches increases, resulting in the inconvenience that the operator's operation work becomes complicated. Also, every time such a function increases, it is necessary to increase switches or the like, and the arrangement of switches or the like around the driver's seat has become complicated.

[0005] An object of the present invention is to provide a work vehicle that can simplify the operator's operation and suppress an increase in the number of switches or the like.

Means for Solving the Problems

[0006] The present invention relates to a work vehicle that performs work in a field by repeatedly performing reciprocating movements interspersed with turning movements, comprising: a traveling body; a field work device supported by the traveling body so as to be able to be raised and lowered and performing work on the field; a state change unit capable of changing the state of the field work device between a working state and a non-working state; a traveling detection unit for detecting the traveling state of the traveling body; a non-working state switching control unit that, when the traveling detection unit detects a transition from the reciprocating movement to the turning movement, controls the state change unit to change the field work device to the non-working state; a working state switching control unit that, when the traveling detection unit detects a transition from the turning movement to the reciprocating movement, controls the state change unit to change the field work device to the working state; and an operating unit configured to enable and disable the non-working state switching control unit and the working state switching control unit with a single operating device. In each of the four states in which the operating device is pressed, the device switches from the set state to another state among the four states: a state in which both the non-work state switching control unit and the work state switching control unit are disabled; a state in which the non-work state switching control unit is enabled and the work state switching control unit is disabled; a state in which the non-work state switching control unit is disabled and the work state switching control unit is enabled; and a state in which both the non-work state switching control unit and the work state switching control unit are enabled.

[0007] According to this invention, since the operating device for switching the non-working state switching control unit and the working state switching control unit to the enabled state and the disabled state, respectively, is composed of a single operating device, the operator only needs to operate this single operating device, making the operator's work easier.

[0008] In the present invention, the vehicle is provided with steering wheels provided on the vehicle body, a vehicle speed acquisition unit for detecting the vehicle speed, a steering acquisition unit for detecting the steering angle of the steering wheels, and a turning angle calculation unit for calculating the turning angle of the vehicle body during turning based on the wheelbase of the vehicle body, the vehicle speed acquisition unit for detecting the vehicle speed, and the steering angle of the steering wheels detected by the steering acquisition unit. Preferably, the vehicle detection unit detects a transition from turning to reciprocating when the calculated turning angle is within a predetermined range and the steering angle detected by the steering acquisition unit is less than a predetermined threshold.

[0009] With this configuration, when detecting the transition from turning to reciprocating motion, it is possible to calculate the transition using the travel speed and steering angle detection results of the steering wheels, which are used in displaying the travel speed, etc. As a result, the transition from turning to reciprocating motion can be detected without using a large number of sensors or other devices, thus reducing costs.

[0010] In the present invention, the vehicle is provided with steering wheels provided on the vehicle body, a vehicle speed acquisition unit for detecting the vehicle speed, a steering acquisition unit for detecting the steering angle of the steering wheels, and a displacement amount calculation unit which calculates a displacement amount, which is the amount by which the vehicle body is displaced along the reference direction during the turning run, based on the direction of travel immediately before the turning run as the reference direction, the wheelbase of the vehicle body, the vehicle speed acquisition unit for detecting the vehicle speed, and the steering angle of the steering wheels for detecting the steering acquisition unit. Preferably, the vehicle detection unit detects a transition from the turning run to the reciprocating run when the calculated displacement amount becomes less than 0.

[0011] With this configuration, when detecting the transition from turning to reciprocating motion, it is possible to calculate the transition using the travel speed and steering angle detection results of the steering wheels, which are used in displaying the travel speed, etc. As a result, the transition from turning to reciprocating motion can be detected without using a large number of sensors or other devices, thus reducing costs.

[0012] In the present invention, the state changing unit has a state changing operation tool that changes the state of the field work device between the working state and the non-working state by human operation, and when the state changing operation to change the state of the field work device to the non-working state is performed by the state changing operation tool, it is preferable that the working state switching control unit temporarily stops the change control.

[0013] In this configuration, when temporarily suspending the change control that transitions to the working state, the operator performs the state change operation using a state change control device. As a result, it becomes possible to temporarily suspend the change control without increasing the number of control devices, thus reducing the number of components.

[0014] In the present invention, when the state change operation to change to the non-work state is performed for a predetermined period of time, it is preferable for the work state switching control unit to discontinue the change control.

[0015] In this configuration, when canceling the change control that transitions to the working state, the operator continues the state change operation using the state change control device for a predetermined time. As a result, it becomes possible to cancel the change control without increasing the number of control devices, thus reducing the number of components. [Brief explanation of the drawing]

[0016] [Figure 1] This is a side view of the tractor. [Figure 2] This is a plan view of the tractor. [Figure 3] This is a plan view of the switching lever, the forced lift lever, and the steering wheel. [Figure 4] This is a block diagram of the control configuration. [Figure 5] This is a flowchart for change control. [Figure 6] This diagram shows the configuration of the control panel. [Figure 7] This diagram shows the transition of the lighting state of the first and second lighting devices when the mode switch is pressed. [Figure 8] This is an explanatory diagram illustrating the reciprocating and turning movements of a tractor. [Figure 9] This is an explanatory diagram schematically showing the reciprocating and turning movements of a tractor in another embodiment. [Modes for carrying out the invention]

[0017] Hereinafter, embodiments of the present invention will be described based on the drawings. 〔Basic Configuration〕 As shown in FIGS. 1 and 2, a tractor A (an example of a work vehicle) includes a traveling body 1, front wheels 2 as steering wheels on the left and right sides of the front part of the traveling body 1, rear wheels 3 on the left and right sides of the rear part of the traveling body 1, left and right rear wheel fenders 4 at the rear part of the traveling body 1, and a driver's seat 5 disposed between the left and right rear wheel fenders 4.

[0018] The traveling body 1 is provided with a steering sensor 2S for detecting the steering angle of the front wheels 2.

[0019] In this tractor A, the front direction of the traveling body 1 is designated as AF, the rear direction as AB, the upward direction as AU, and the downward direction as AD, as shown in the figure. Also, the left direction of the traveling body 1 is designated as AL and the right direction as AR, as shown in the figure.

[0020] As shown in FIG. 8, this tractor A performs work traveling in the field by repeating a reciprocating travel Rt with a turning travel Tt interposed therebetween.

[0021] As shown in FIGS. 1 and 2, the tractor A houses an engine E inside a bonnet 6 at the front part of the traveling body 1. A transmission case 7 connected to the rear end of this engine E is provided with a hydrostatic continuously variable transmission T.

[0022] The tractor A is provided with a pair of left and right lift arms 8 at the upper position of the rear end of the transmission case 7. The left and right lift arms 8 are swingably supported by the transmission case 7 via a shaft body with its base end in the lateral direction (the direction of AR - AL).

[0023] A rotary tiller B, a field work device that performs work on the field, is connected to the lift arm 8 via a three-point linkage mechanism. The tractor A is equipped with a lift cylinder 9 (an example of a state-changing part) at the rear of the transmission case 7 that drives the left and right lift arms 8 up and down, and changes the state of the rotary tiller B between working and non-working states. In other words, the rotary tiller B is supported by the traveling machine body 1 so that it can be raised and lowered via the lift arm 8 and the lift cylinder 9.

[0024] As shown in Figures 1 and 3, the steering wheel 11 and the instrument panel 12 are located in front of the driver's seat 5.

[0025] As shown in Figure 2, tractor A is equipped with a main gear lever 13 for setting the travel speed V and a lifting lever 14 for controlling the raising and lowering of the rotary tiller B, located to the right of the driver's seat 5 (in the direction of AR). Tractor A is also equipped with a vehicle speed sensor VS (see Figure 4) for detecting the steering speed of the traveling machine 1.

[0026] The lifting lever 14 is supported so that it can be swung along the front-rear direction (AF-AB direction). The set position of this lifting lever 14 is detected by a potentiometer-type lifting lever sensor 14S at its base end (see Figure 4).

[0027] As shown in Figure 3, tractor A is equipped with a switch lever 15 on the left side of the steering wheel 11 (in the direction of AL) for switching the direction of travel of the vehicle body 1 forward and backward. It is also equipped with a forced lifting lever 16 (state change control device) on the right side of the steering wheel 11 (in the direction of AR) for raising and lowering the lift arm 8.

[0028] The selector lever 15 is positioned overlapping with the steering wheel 11 in a plan view. This selector lever 15 extends outward to the left and is supported so as to be operable along a linear operating path M that runs along the longitudinal direction of the vehicle body 1. The selector lever 15 is configured to be set to a neutral position N in the middle of this operating path M, a forward position F ahead of the neutral position N, and a reverse position R behind the neutral position N.

[0029] The switching lever 15 has its operating end supported inside the steering column, and its set position is detected by a potentiometer-type switching lever sensor 15S located at its base end.

[0030] [Forced lifting lever] The forced lifting lever 16 is positioned overlapping with the steering wheel 11 in a plan view. This forced lifting lever 16 extends to the right from the handle post 17 and is supported so as to be operable in the vertical direction.

[0031] As shown in Figure 3, the forced lifting lever 16 is held in the neutral position Ln when not being operated. Furthermore, the forced lifting lever 16 is supported so as to be operable to an upward position Lu, which is above the neutral position Ln, and a downward position Ld, which is below the neutral position Ln.

[0032] A forced lifting lever sensor 16S is provided at the base end of the forced lifting lever 16. The forced lifting lever sensor 16S detects whether the forced lifting lever 16 has been operated to the neutral position Ln, the upward position Lu, or the downward position Ld.

[0033] As shown in Figure 1, tractor A raises the rotary tiller B to the set height by operating the forced lifting lever 16 to the raised position Lu while the rotary tiller B is being lowered by automatic tilling depth control.

[0034] Furthermore, when the rotary tiller B is raised to the set height, tractor A lowers the rotary tiller B to the working height for automatic tilling depth control by operating the forced lifting lever 16 to the lowered position Ld. In other words, by manually operating the forced lifting lever 16, the operator can change the state of the rotary tiller B between a working state where it is lowered to the working height and a non-working state where it is raised to the set height.

[0035] Furthermore, regardless of whether the lifting lever 14, the forced lifting lever 16, or the switching lever 15 is operated, when the operator raises the rotary tiller B to the set height, the clutch of the transmission system is disengaged in conjunction with the rise, and the driving force transmitted from the traveling machine 1 to the rotary tiller B is interrupted.

[0036] The lifting and lowering of this rotary tilling device B is achieved by the control device C shown in Figure 4, which controls the lift cylinder 9.

[0037] [Rotary tiller] As shown in Figures 1 and 2, the tractor A has a rotary tilling device B connected to the rear end of the traveling body 1 via a three-point linkage mechanism. The three-point linkage mechanism has left and right lower links 41 at the rear end position and a single top link 42 above these.

[0038] The left and right lower links 41 are supported by the left and right lift arms 8 by being lifted by the lift rods 43. This allows the left and right lift arms 8 to be raised and lowered by the extension or contraction of the lift cylinder 9, thereby raising and lowering the rotary tilling device B via the three-point linkage mechanism.

[0039] The rotary tiller B has multiple tilling tines 44 that rotate together with a lateral drive shaft by the driving force transmitted from the transmission case 7, and is equipped with an upper cover 45 that covers the tilling tines 44 and a rear cover 46.

[0040] [Control device] As shown in Figure 4, the control device C includes a control processing unit 50 such as a microprocessor or a DSP (digital signal processor).

[0041] The control processing unit 50 includes a lifting control unit 51, which is composed of software, and an automatic work state switching unit 52. Note that the lifting control unit 51 and the automatic work state switching unit 52 are not limited to being composed of software; they may also be composed of hardware such as logic circuits.

[0042] The control processing unit 50 receives signals from the vehicle speed sensor VS (vehicle speed acquisition unit), steering sensor 2S (steering acquisition unit), lift lever sensor 14S, switching lever sensor 15S, forced lift lever sensor 16S, lift arm sensor 8S, and the mode switch 18, which will be described later.

[0043] The control processing unit 50 outputs a control signal to the lifting control valve 55, which supplies and discharges hydraulic fluid to the lift cylinder 9.

[0044] [Lifting and lowering control unit] The lifting control unit 51 performs the lifting and lowering operation of the lift arm 8 based on the set position of the lifting lever 14 obtained from the detection signal of the lifting lever sensor 14S and the set position of the forced lifting lever 16 obtained from the detection signal of the forced lifting lever sensor 16S.

[0045] The lifting control unit 51 performs position control to raise or lower the rotary tiller B to a height corresponding to the set position when the lifting lever 14 is set to a predetermined position control range. In this position control, a target height is set corresponding to the set position of the lifting lever 14, and the lift cylinder 9 is controlled in a manner that feeds back the detection signal from the lift arm sensor 8S.

[0046] [Automatic operation state switching unit] The automatic work state switching unit 52 includes a travel detection unit 52a that detects the travel state of the traveling machine 1. When the travel detection unit 52a detects a transition from reciprocating travel Rt to turning travel Tt as shown in Figure 8, it performs change control to change to a non-working state in which the rotary tiller B is raised to a set height. When it detects a transition from turning travel Tt to reciprocating travel Rt, it performs change control to change to a working state in which the rotary tiller B is lowered to the working height.

[0047] The automatic work state switching unit 52 is equipped with a turning angle calculation unit 52b that calculates the turning angle Tθ (see Figure 8), as shown in Figure 4. Here, the turning angle Tθ is the angle by which the traveling machine 1 has turned from the start of turning travel Tt. The travel detection unit 52a detects the transition from turning travel Tt to reciprocating travel Rt based on the calculation result of the turning angle calculation unit 52b.

[0048] The travel detection unit 52a detects a transition from turning travel Tt to reciprocating travel Rt when the turning angle Tθ calculated by the turning angle calculation unit 52b is within a predetermined range (for example, 130 degrees to 180 degrees) and the steering angle θ detected by the steering sensor 2S is less than a predetermined threshold (for example, less than 5 degrees). Although not described in detail here, the travel detection unit 52a detects a transition from reciprocating travel Rt to turning travel Tt in a similar manner.

[0049] The turning angle calculation unit 52b calculates the turning angle Tθ using a predetermined formula. For example, the turning angle calculation unit 52b calculates the turning angle Tθ based on the wheelbase Hb of the mobile body 1 shown in Figure 1, the travel speed V detected by the vehicle speed sensor VS, and the steering angle θ of the front wheels 2 detected by the steering sensor 2S. Specifically, it is as follows:

[0050] The rotation angle for each period t (for example, 10 ms) is defined as the periodic rotation angle θd, and the control period dt is defined as 1 / t. Then, the rotation angle calculation unit 52b calculates the periodic rotation angle θd using the formula "θd = (V / Hb)tanθ·dt". The rotation angle calculation unit 52b then calculates the cumulative value obtained by summing up the periodic rotation angles θd as the rotation angle Tθ.

[0051] Furthermore, the automatic work state switching unit 52 includes a non-work state switching control unit 52c that performs change control to change the rotary tiller B to a non-work state, and a work state switching control unit 52d that performs change control to change the rotary tiller B to a work state.

[0052] The flowchart shown in Figure 5 illustrates the control flow of the automatic work state switching unit 52.

[0053] In this control, the driving detection unit 52a executes a process to detect the driving state (step #001).

[0054] When the travel detection unit 52a detects a transition from reciprocating travel Rt to turning travel Tt (Yes in step #002), the non-working state switching control unit 52c performs a change control on the lift cylinder 9 to change the rotary tilling device B to a non-working state (step #004). However, if the non-working state switching control unit 52c is OFF (disabled) due to the operation of the mode switch 18 described later, step #004 is not executed and the system proceeds to step #001.

[0055] When the travel detection unit 52a detects a transition from turning travel Tt to reciprocating travel Rt (Yes in step #003), the work state switching control unit 52d performs change control on the lift cylinder 9 to change the rotary tilling device B to the working state (step #005). However, if the work state switching control unit 52d is OFF (disabled) due to the operation of the mode switch 18 described later, step #005 is not executed and the system proceeds to step #001.

[0056] The automatic work state switching unit 52 repeats the processes from #001 to #005.

[0057] [Operation unit] As shown in Figure 2, tractor A is equipped with an operating unit S on which multiple switches are located. As shown in Figure 6, in this embodiment, the operating unit S is equipped with a momentary type mode switch 18 (an example of an operating device). To the left of the mode switch 18 on the operating unit S, "automatic lifting function" and "automatic lowering function" are indicated, and a first lighting device L1 and a second lighting device L2 corresponding to them are provided.

[0058] When the non-working state switching control unit 52c is turned ON (enabled), the first lighting device L1 lights up, and when the working state switching control unit 52d is turned ON (enabled), the second lighting device L2 lights up.

[0059] As shown in Figure 7, each time the mode switch 18 is pressed, "both the non-working state switching control unit 52c and the working state switching control unit 52d are turned OFF (disabled)." Non-working state switching control unit 52c The system repeatedly switches between "only ON (enabled)", "only the work state switching control unit 52d ON (enabled)", and "both the non-work state switching control unit 52c and the work state switching control unit 52d ON (disabled)". This configuration allows the non-work state switching control unit 52c and the work state switching control unit 52d to be operated between ON (enabled) and OFF (disabled) using a single operating device, the mode switch 18.

[0060] Furthermore, the control unit S is equipped with an adjustment switch 19 that adjusts the timing for the rotary tilling device B to be changed to the working state by the work state switching control unit 52d. Although the details will not be explained here, this is achieved, for example, by changing the conditions under which the travel detection unit 52a detects the transition from turning travel Tt to reciprocating travel Rt.

[0061] When the rotary tiller B is being transitioned from a non-working state to a working state by the work state switching control unit 52d, if a state change operation is performed using the forced lifting lever 16 to change the rotary tiller B back to a non-working state, that is, if the forced lifting lever 16 shown in Figure 3 is moved to the raised position Lu, the work state switching control unit 52d temporarily stops the change control. After that, when the forced lifting lever 16 is returned to its original lifting neutral position Ln, the rotary tiller B resumes the transition to the working state.

[0062] If the rotary tiller B is continuously operated for a predetermined time (for example, 10 seconds) using the forced lifting lever 16 to change its state to a non-working state, that is, by moving the forced lifting lever 16 to the raised position Lu, the working state switching control unit 52d will stop the change control. Both the non-working state switching control unit 52c and the working state switching control unit 52d will turn OFF (disabled), and the rotary tiller B will be operated manually using the forced lifting lever 16.

[0063] [Another embodiment] The following are examples of alternative embodiments that modify the above embodiments.

[0064] (1) In the above embodiment, a configuration in which the transition from turning travel Tt to reciprocating travel Rt is detected based on the turning angle Tθ calculated by the turning angle calculation unit 52b was described as an example, but the present invention is not limited to the above embodiment. For example, as shown in Figure 9, the direction of travel immediately before turning travel Tt is set as the reference direction SD, and the configuration may include a displacement amount calculation unit 52e (see Figure 4) that calculates a displacement amount DL, which is the amount that the traveling body 1 has been displaced along the reference direction SD during turning travel Tt, based on the wheelbase Hb of the traveling body 1, the travel speed V detected by the vehicle speed sensor VS, and the steering angle θ of the front wheel 2 detected by the steering sensor 2S.

[0065] At this time, for example, when the displacement amount DL calculated by the displacement amount calculation unit 52e becomes less than 0, the transition from rotational travel Tt to reciprocating travel Rt is detected.

[0066] (2) In the above embodiment, a configuration in which the transition from turning travel Tt to reciprocating travel Rt is detected based on the turning angle Tθ calculated by the turning angle calculation unit 52b was described as an example. However, the present invention is not limited to the above embodiment, and for example, a configuration in which the transition from turning travel Tt to reciprocating travel Rt is detected using a positioning device that utilizes a satellite positioning system may also be used.

[0067] (3) In the above embodiment, the rotary tiller B was described as a field work device, with the state in which the rotary tiller B is lowered to the working height being considered the working state, and the state in which the rotary tiller B is raised to the set height being considered the non-working state. However, the embodiment is not limited to this, and for example, a fertilizer application device that supplies fertilizer to the field may be described as a field work device, with the state in which fertilizer is being supplied being considered the working state, and the state in which fertilizer supply is stopped being considered the non-working state.

[0068] (4) In the above embodiment, a configuration was described in which the change control of the work state switching control unit 52d is temporarily stopped or canceled by manually operating the forced lifting lever 16. However, the present invention is not limited to the above embodiment, and for example, a configuration may be provided with a separate dedicated operating tool.

[0069] (5) In the above embodiment, a configuration in which the running machine body 1 is equipped with front wheels 2 and rear wheels 3 was described as an example, but the present invention is not limited to the above embodiment, and may be configured as a semi-crawler specification in which crawlers are provided instead of rear wheels 3, or as a full crawler specification in which crawlers are provided instead of front wheels 2 and rear wheels 3.

[0070] (6) In the above embodiment, the operating unit S was described as having a configuration in which the mode switch 18 is a momentary type switch. However, the present invention is not limited to the above embodiment, and for example, the mode switch 18 may be a dial type switch or the like.

[0071] Furthermore, the configurations disclosed in the above embodiments (including other embodiments, the same applies hereinafter) can be applied in combination with configurations disclosed in other embodiments, as long as no inconsistencies arise. In addition, the embodiments disclosed herein are illustrative, and the embodiments of the present invention are not limited thereto, and can be modified as appropriate without departing from the object of the present invention. [Industrial applicability]

[0072] This invention can be used not only for tractors but also for various other work vehicles such as combine harvesters and rice transplanters. [Explanation of Symbols]

[0073] 1: Mobile body 16: Forced lifting lever (state change control device) 18: Mode switch (operating device) 52a: Driving detection unit 52b: Swivel angle calculation unit 52c: Non-working state switching control unit 52d: Operation State Switching Control Unit Rt: Round trip Tt: Turning and driving S:Operation section Hb: Wheelbase Tθ: Swivel angle V: Traveling speed θ: Steering angle DL: Displacement SD: Reference direction

Claims

1. A work vehicle that operates within a field by repeatedly moving back and forth with turning sections in between, The vehicle and A field work device is supported on the aforementioned traveling machine so as to be able to be raised and lowered, and is used for performing work in the field. The aforementioned field work device includes a state changing unit that can change between a working state and a non-working state, A running detection unit for detecting the running state of the aforementioned mobile unit, When the travel detection unit detects a transition from the reciprocating travel to the turning travel, the non-working state switching control unit performs change control on the state change unit to change the field work device to the non-working state, When the travel detection unit detects a transition from turning travel to reciprocating travel, the work state switching control unit performs change control on the state change unit to change the field work device to the work state, The non-working state switching control unit and the working state switching control unit are provided, and an operating unit is configured to allow the operating unit to be switched between an enabled state and an disabled state with a single operating device. A work vehicle that, each time the operating device is pressed, switches from one of the four set states to another of the four states in four states: a state in which both the non-work state switching control unit and the work state switching control unit are disabled; a state in which the non-work state switching control unit is enabled and the work state switching control unit is disabled; a state in which the non-work state switching control unit is disabled and the work state switching control unit is enabled; and a state in which both the non-work state switching control unit and the work state switching control unit are enabled.

2. Steering wheels provided on the aforementioned running body, A vehicle speed acquisition unit that detects the travel speed of the aforementioned mobile vehicle, A steering acquisition unit that detects the steering angle of the steering wheels, The system includes a turning angle calculation unit that calculates the angle at which the vehicle turns during the turning maneuver as the turning angle, based on the wheelbase of the vehicle, the vehicle speed detected by the vehicle speed acquisition unit, and the steering angle of the steering wheels detected by the steering acquisition unit. The work vehicle according to claim 1, wherein the travel detection unit detects a transition from the turning travel to the reciprocating travel when the calculated turning angle is within a predetermined range and the steering angle detected by the steering acquisition unit is less than a predetermined threshold.

3. Steering wheels provided on the aforementioned running body, A vehicle speed acquisition unit that detects the travel speed of the aforementioned mobile vehicle, A steering acquisition unit that detects the steering angle of the steering wheels, The system includes a displacement calculation unit that calculates the amount of displacement, which is the amount the vehicle body is displaced along the reference direction during the turning maneuver, based on the direction of travel immediately before the turning maneuver, the wheelbase of the vehicle body, the travel speed detected by the vehicle speed acquisition unit, and the steering angle of the steering wheels detected by the steering acquisition unit. The work vehicle according to claim 1, wherein the travel detection unit detects a transition from turning travel to reciprocating travel when the calculated displacement amount becomes less than 0.

4. The state changing unit has a state changing operation tool that manually changes the state of the field work device between the working state and the non-working state. The work vehicle according to claim 1, wherein when the state change operation is performed by the state change operating device to change the state of the field work device to the non-work state, the work state switching control unit temporarily stops the change control.

5. The work vehicle according to claim 4, wherein when the state change operation to change to the non-work state is performed for a predetermined period of time, the work state switching control unit cancels the change control.

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