JP2886048B2 - Work vehicle control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power device, a working device driven by the power of the power device, power on / off means for turning on and off power transmission from the power device to the working device, and The present invention relates to a control device for a work vehicle provided with on / off state detection means for detecting an on / off state of on / off means, and control means for controlling operation of the working device.

[0002]

2. Description of the Related Art For example, a control device for a work vehicle transmits an engine mounted on a combine as a work vehicle to a power device, a threshing device to a work device, and a power on / off means to transmit power of the engine to a threshing device. In the threshing clutch, the on / off state detecting means is configured as a threshing switch for detecting the operation state of the threshing clutch. Control is performed so that threshing is performed in this state. Conventionally, after confirming that the threshing switch is in the ON state, that is, that the power from the engine is being transmitted to the threshing apparatus with the threshing clutch engaged, control on the threshing apparatus is started.

[0003]

However, in the above prior art, since the control is activated on the premise that the threshing switch has not failed, proper control cannot be performed when the threshing switch has failed. Will be. For example,
In the ON failure that occurs when the threshing switch is short-circuited to the power supply, for example, the power is transmitted even though the threshing clutch is disengaged and the power from the engine is not transmitted to the threshing device. An erroneous determination will cause unnecessary control to be activated. On the other hand, in an OFF failure that occurs when the threshing switch is short-circuited to the earth side, etc., power is transmitted even though the threshing clutch is engaged and power from the engine is transmitted to the threshing device. As a result, the control is stopped because it is incorrectly judged that the operation has not been performed, and as a result, the work equipment is stopped in an inappropriate state, causing the work equipment etc. to be damaged in the worst case, or the control is not started and the work is executed There is a problem that it is no longer possible.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to solve the above-mentioned disadvantages of the prior art by making it possible to accurately determine the state of power transmission from a power unit to a working unit. It is in.

[0005]

A first characteristic configuration of a work vehicle control device according to the present invention is a power generation detection means for detecting generation of power of the power device, and a work detection for detecting operation of the work device. Means, wherein the control means is configured to detect a state in which the on / off state detection means detects the input of the power transmission based on information of the power generation detection means, the work detection means, and the on / off state detection means. An on-failure determination process for determining whether or not an on-failure is to be fixed, and an off-failure for determining whether or not the on-failure is to be fixed in a state in which the on / off state detecting means detects the cutoff of the power transmission. The determination process is performed so that the on / off state detection unit determines whether or not there is a failure.

[0006] In a second feature configuration, in addition to the first feature configuration, the control means is configured to control whether the on / off state detecting means is not out of order and when the on / off state detecting means is in the on state. The present invention is characterized in that the control for the working device is started, and the control for the working device is not started when the ON / OFF state detecting means is out of order.

[0007]

According to the first characteristic configuration of the present invention, for example, power is generated from a power device based on detection information of the power generation detection means and the work detection means, and the work device operates. If the ON / OFF state detecting means detects the cutoff of the power transmission, the ON / OFF state detecting means detects the cutoff of the power transmission by the OFF failure determination processing. Is determined to be an off fault that is fixed at. Further, when it is determined that power is generated from a power device and the operation of the work device is stopped based on the detection information of the power generation detection device and the work detection device, the on / off state is determined. If the detection means is in the state of detecting the input of the power transmission, the on-failure determination processing determines that the on / off state detection means is an on-failure that is fixed in a state of detecting the input of power transmission. . In addition, the control unit determines whether the ON / OFF state detection unit is faulty by executing the OFF fault determination process and the ON fault determination process, respectively, so that any of the ON fault and the OFF fault is determined. It can be properly determined.

Further, according to the second characteristic configuration, when the on / off state detecting means for detecting the on / off state of the power transmission from the power unit to the work apparatus is determined not to be out of order, the power transmission of the power transmission is performed. When the entering state is detected, control for the working device is performed. On the other hand, when the ON / OFF state detecting means is determined to be faulty, the control for the working device is not performed.

[0009]

Therefore, according to the first characteristic configuration of the present invention, the failure of the on / off state detecting means for detecting the on / off state of the power transmission from the power unit (engine or the like) to the work apparatus is an ON failure. In this case, the power transmission from the power unit to the work equipment can be accurately determined based on the failure determination information, and the operation of the work equipment can be determined accurately. It will be controlled in an appropriate state.

According to the second characteristic configuration, necessary control for the working device is performed in a state where power from the power device is transmitted to the working device, while unnecessary control is performed in a state where the power is not transmitted. Malfunctions such as damaging the work equipment by starting up the appropriate control, or the control is stopped even though the power from the power unit is transmitted to the work equipment, The occurrence of troubles such as stoppage of operation and inability to work can be effectively avoided.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a combine as a working vehicle will be described below with reference to the drawings. As shown in FIG. 2, the combine includes a pair of right and left crawler traveling devices 1, a threshing device 2 as a working device, and
A reaper G is attached to the front of a body K having a driver's seat 3 so as to be able to swing up and down.

The cutting section G comprises a device 4 for raising the planted grain culm, a cutting blade 5 for cutting the root of the planted grain culm that has been raised, and an auxiliary for collecting the cut and harvested grain culm and transporting it backward. The transporting device 6 includes a transporting device 6 and a vertical transporting device 8 that transports the transported harvested culm toward the threshing feed chain 15 of the threshing device 2 while gradually turning over.
In the drawing, S0 is a stock sensor that contacts the stock of the harvested grain culm at the transport start end of the vertical transport device 8, and the harvested grain culm contacts the stock sensor S0 during the harvesting operation. The state where the stock sensor S0 is ON continues, and when the harvesting operation is completed, the supply of the harvested grain culm is interrupted so that the grain stem does not contact the stock sensor S0 and the stock sensor S0 is turned off. The presence or absence of the cereal stem transported by the vertical transport device 8 is detected by the stock sensor S0.

The vertical transport device 8 includes a nipping transport device 8A for nipping and transporting the root side of the harvested grain culm, an engaging transport device 8B for latching and transporting the ear side of the harvested grain culm, and a grain culm guide plate 8C. The harvested culm from the auxiliary transport device 6 is transported toward the rear of the machine in a vertical position, and is transferred to the feed chain 15 after being changed to a sideways position at a transport end portion. ing. Although not described in detail, the vertical transport device 8 is pivotally mounted at the end portion around the horizontal axis P so as to be vertically swingable, and is supplied from the auxiliary transport device 6 with the vertical swing. The support position of the harvested grain culm is changed in the direction of the culm, the position of the harvested grain culm transferred from the vertical transport device 8 to the feed chain 15 is changed in the culm direction, and the handling depth in the threshing device 2 is changed. Are configured to be changed and adjusted.

As shown in FIG. 2, an inverted U-shaped member 13 which is also used as a frame of the
A pair of head sensors Sa and Sb for detecting the position of the tip of the transported grain culm conveyed by the above are provided at intervals in the direction of the culm body of the grain culm, and the installation location of the pair of tip sensors Sa and Sb Is set on the lower side in the grain stalk transport direction from the handling depth adjustment point, that is, the starting end of the vertical transport device 8. Each of the pair of ear sensors Sa and Sb is reciprocatingly oscillated to the lower side of the conveyance due to contact with the grain culm and is urged to return to the upper side of the conveyance, and a switch for detecting the reciprocating oscillation of the sensor bar. Consists of In other words, the sensor bar retreats and swings due to contact with the grain
If N is operated, the presence of a grain stalk is detected, and if the switch is OFF, the absence of a grain stalk is detected. Although not described in detail, the state in which only the sensor Sb on the stock side of the pair of ear sensors Sa and Sb detects the presence of a grain culm is regarded as an appropriate handling depth state, and maintained in that state. The vertical transport device 8 is vertically swung around the horizontal axis P.

As shown in FIG. 3, the threshing apparatus 2 comprises a handling drum 24 for handling and processing threshing grain stems nipped and conveyed by the feed chain 15 from the front to the rear of the machine.
, A receiving net 43 disposed below the handling room A, a swing sorting plate 44 for swinging and sorting the material leaked from the receiving net 43, and a swing Karamin 45, which blows the sorting wind to the sorting plate 44, a rotary diffusion cylinder 46 acting on the straw chips sent out from the handling room A, and sucks and discharges dust generated inside the threshing device outside the machine. A dust exhaust fan 7; a first screw 28 for collecting the grains as the first thing from the swing sorting plate 44; a second screw 9 for collecting the grains mixed with the straw as a second thing; And a thrower 10 for reducing the second product collected by the number 9 screw onto the swing sorting plate 44. In the figure, reference numeral 11 denotes a grain sheave disposed above the first screw 28, and reference numeral 12 denotes a chaff sheave located above the Glen sheave 11.

At the upper part of the feed chain 15, the culm to be conveyed is pressed downward to feed chain 15
, A rail mechanism 26 is provided. That is,
Each rail of the pressing member 26a composed of a plurality of rails pivotally connected in the transport direction is separately elastically urged downward by a coil spring or the like, and pivots between the first rail and the second rail from the front. A culm thickness sensor S8 using a potentiometer is provided to detect the upward displacement of the supporting point. As shown in FIG. 8, the culm thickness sensor S8 includes a fixed resistor R1 on the high voltage side, a fixed resistor R2 on the low voltage side, and a fixed resistor R2 between the two terminals a and b for supplying power supply voltage. , The voltage at the upper limit position a ′ of the moving contact c of the volume VR is, for example, lower than the power supply voltage (for example, 5 V) supplied to the terminal a on the high voltage side. Also becomes a low voltage (for example, 4.5 V), and the lower limit position b ′ of the moving contact c of the volume VR.
Is higher (for example, 0.5 V) than the voltage (for example, 0 V) of the terminal b on the low voltage side. Therefore, when the fixed resistor R1 and R2 are not provided and only the volume VR is used, whether the volume VR is not faulty and its moving contact c is at the upper or lower limit position, or whether the volume VR has failed and the moving contact c is high voltage This eliminates the problem that it is not possible to distinguish whether a short-circuit has occurred to the terminal on the low-side or low-voltage side.

The culm thickness sensor S8 is a feed chain 1
5 to detect the thickness of the grain culm sandwiched between the culm 5 and the rail mechanism 26. The thickness of the grain culm detected by the culm thickness sensor S8 and a feed chain sensor S6 described later.
Feed chain 15 detected by (see FIG. 4)
The product of the detected amount and the transport amount of the threshed culm transported by the feed chain 15 is proportional to the transported amount of the threshing cereal culm transported by the feed chain 15. The transport amount of the cereal stem is detected.

Next, the power transmission system of the combine will be described. As shown in FIG. 4, the driving force of a diesel engine E as a power unit is transmitted to a continuously variable transmission 19 for traveling via a belt transmission, and the output of the continuously variable transmission 19 after shifting is output. The power is transmitted to the mission case 18. Then, the pair of left and right crawler traveling devices 1 is driven via the auxiliary transmission D in the transmission case 18. The output of the continuously variable transmission 19 after shifting is transmitted through the transmission case 18,
The cutting unit G is driven via the one-way clutch 27 to drive each unit of the cutting unit G so that the cutting unit G is driven only when the machine body advances. still,
The sub-transmission D is operated by a sub-transmission lever (not shown) provided in the driver's seat 3. Further, the transmission case 18 is provided with a speed sensor S1 for detecting an input rotation speed from the continuously variable transmission 19 to detect a vehicle speed or a grain culm conveying speed of the cutting unit G. I have.

As shown in FIG. 4, the power of the engine E is supplied to the engine E so that the threshing device 2 is driven.
After passing through a threshing clutch 14 as a power on / off means for turning on / off the power transmission from the thruster 24 to the threshing apparatus 2
, The rotation shaft 45a of the carving 45, and the first screw 28 via a belt transmission and a gear transmission. The threshing clutch 14 is provided with a threshing switch S3 as on / off state detecting means for detecting the on / off state of the clutch. Further, by detecting the number of revolutions on the output shaft of the engine E, the engine E is detected.
An engine speed detection sensor S4 is provided as power generation detection means for detecting the generation of power. The driving force of the engine E transmitted to the first screw 28 is transmitted to the rotating shaft 46 a of the diffusion cylinder 46, the second screw 9, and the rotating shaft 44 a of the swing selection plate 44 by a belt in that order. . Further, a screw rotation number detection sensor S5 for detecting the rotation number of the second screw 9 is provided, and since the second screw 9 rotates during the operation of the threshing device 2, the screw rotation number detection sensor S5 detects the screw rotation number sensor S5.
An operation detecting means for detecting the operation of the device is constituted.

The rotation shaft 24a of the handle cylinder 24 is transmitted by a belt via a split pulley type first transmission 20 (belt continuously variable transmission) in which the power of the engine E is disposed in the middle of the transmission path. It is rotationally driven by the driving force. The first transmission 20 includes an input pulley 20b attached to an input shaft 20a to which the driving force of the engine E is transmitted.
And an output pulley 20c whose belt is transmitted to the input pulley 20b.
Is attached to the rotary shaft 24a. The input pulley 20b is configured as a split pulley type, and the diameter of the pulley is changed based on the movement of the pulley in the thickness direction. A shift operation of the first transmission 20 is performed to change the rotation speed of the first transmission 24. In addition, the rotating shaft 24a of the handling cylinder 24 includes
A cylinder rotation speed sensor S2 for detecting the rotation speed is additionally provided.

The dust discharging fan 7 is driven to rotate by a driving force transmitted from a rotating shaft 46a of the diffusion cylinder 46 to a belt via a split pulley-type second transmission 21 (a belt continuously variable transmission). It has become. The second transmission 21 includes an input pulley 21 attached to an input shaft 21 a which is gear-transmitted from a rotation shaft 46 a of the diffusion cylinder 46.
b and an output pulley 21c whose belt is transmitted to the input pulley 21b. The output pulley 21c is attached to the rotary shaft 7a of the dust discharging fan 7. The input pulley 21b and the output pulley 21c are both configured as split pulleys, and when one diameter is changed from small to large, the other diameter is changed from large to small in conjunction. The driving force transmitted to the dust exhaust fan 7 via the second transmission 21 is a gear-type reduction mechanism 22 and a clutch 23.
The transmission is transmitted to the drive sprocket 15a of the feed chain 15 through the second transmission 2
1 is operated, the dust discharge fan 7 and the feed chain 15 are linked to change the speed. still,
The drive sprocket 15a of the feed chain 15 is provided with a feed chain sensor S6 for detecting the number of revolutions thereof in order to determine the feed speed of the feed chain 15.

As shown in FIG. 1, a control device 100 using a microcomputer is provided.
The stock sensor S0, the speed sensor S1, the handle cylinder speed sensor S2, the threshing switch S3, the engine speed sensor S4, the screw speed sensor S5, the feed chain sensor S6, and the culm. Each signal from the thickness sensor S8 and the pair of head sensors Sa and Sb is input, and the control device 100 outputs drive signals to the first and second transmissions 20 and 21 and the alarm device 25. Is output. The alarm device 25 includes a buzzer and a blinking lamp provided in the driver's seat 3.

Then, using the control device 100,
A control means C for controlling the operation of the threshing device 2 is provided, and this control means C, as shown in FIGS. 7A and 7B, transfers the threshing grain culm by the feed chain sensor S6 and the culm thickness sensor S8. Based on the information on the amount, the operation of the first transmission 20 is controlled so that the rotation speed of the handling drum 24 increases as the amount of threshing culm transport increases, and the feed rate increases as the amount of threshing cereal culm transport increases. The operation of the second transmission 21 is controlled so that the transport speed of the chain 15 increases.

In addition, the control means C controls the engine speed detection sensor S4 and the screw speed detection sensor S4.
5 and the information of the threshing switch S3, it is configured to determine whether or not the threshing switch S3 is faulty. Further, the control means C is configured to determine whether the threshing switch S3 is not faulty and the threshing switch S3 Is activated so that the control for the threshing apparatus 2 is started when the state is in the ON state, and the control for the threshing apparatus 2 is not started when the threshing switch S3 is out of order.

Since the first transmission 20 and the second transmission 21 are both constituted by a belt continuously variable transmission as described above, the speed change operation is performed by each of the pulleys 20b, 2
It is necessary to start under the condition that 0c and 21b, 21c are rotating respectively. Therefore, the control device 10
0 is a condition that the first transmission 20 has the threshing switch S3 in the ON state, and that the rotation speed of the engine E detected by the engine rotation speed detection sensor S4 is equal to or higher than a certain value. In addition, the second speed change device 21 performs a speed change operation on condition that the rotation speed of the second screw 9 detected by the screw rotation speed detection sensor S5 is equal to or higher than a certain value. .

Next, the control operation of the control device 100 will be described with reference to the flowcharts shown in FIGS. This control operation is executed at predetermined time intervals by interrupt processing. First, failure detection is performed as an ON failure determination process for detecting an ON failure fixed in a state where the threshing switch S3 is in an ON state, that is, a state where power transmission from the engine E to the threshing device 2 is detected (1). And the threshing switch S3 is in the OFF state, that is, the engine E
The failure detection (2) is executed as an OFF failure determination process for detecting a fixed OFF (off) failure in a state where the power transmission to the threshing apparatus 2 is detected and the threshing switch S
If 3 is faulty, no control is performed. If the threshing switch S3 is not at fault, the state in which the threshing switch S3 is ON and the stock sensor S0 is ON is set to a state where the control condition is satisfied, and if this control condition is satisfied. The first transmission 20 and the second transmission so that the rotation speed and the feed chain speed are appropriate for the threshing grain culm transport amount detected by the feed chain sensor S6 and the culm thickness sensor S8. 21
(See FIG. 7).

In the failure detection (1), as shown in FIG. 6 (a), after confirming that the engine E has a rotation speed equal to or higher than the minimum rotation speed rmin and power is being generated, the threshing switch S3 Check the status of. Here, if the rotation speed (second rotation speed) of the second screw 9 has not reached the appropriate rotation speed r2 when the threshing switch S3 is ON and a predetermined time has elapsed after the switch is turned ON, the threshing clutch 14 Is determined to have not been operated, so that the threshing switch S
3 is determined to be an ON failure. In addition, threshing switch S3
Waiting until a predetermined time elapses after turning ON is that the second rotation speed may not reach the appropriate rotation speed r2 immediately after the threshing clutch 14 is turned on and the threshing switch S3 is turned on. This is to prevent the switch S3 from being erroneously determined to be an ON failure.

In the failure detection (2), as shown in FIG. 6 (b), it is confirmed that the engine E has a rotation speed equal to or higher than the minimum rotation speed rmin and power is generated. It is checked whether or not the number of rotations 9 (second number of rotations) has reached the appropriate number of rotations r2. Here, when the second rotation speed has reached the appropriate rotation speed r2, the threshing switch S3 is set to O.
In the FF state, the threshing switch S3 is in the OFF state while the threshing clutch 14 is engaged and operated, so that the OFF failure of the threshing switch S3 is determined.

[Alternative Embodiment] In the above embodiment, the shift result of the split pulley type first transmission device 20 for shifting the rotation speed of the cylinder is detected by the rotation speed sensor S2. In addition to this, for example, As shown in FIG.
0b is provided with a volume Ra interlocked with the operation position of the speed change motor M for changing the diameter of the pulley.
May be input to the control device 100 to detect the shift state based on the input voltage value. In the figure, a and b are power supply terminals, and Rb is a ground resistance. Here, a configuration for detecting a failure such as a contact failure of the contact point of the volume Ra will be described with reference to FIG.
As shown in (b), when the output voltage of the volume Ra suddenly decreases (becomes 0 V or the like) when the speed change motor M is operated at a constant speed, the contact point indicates a poor contact at that point. It is determined that it is awake.

In the above embodiment, the failure detection is performed only for the threshing switch S3. However, the failure detection may be similarly performed for the stock switch S0 used to determine whether the control condition is satisfied. FIG. 10 shows a flowchart in this case. First, the height of the cutting unit G is checked by a cutting height detection device (not shown). When the mowing part G is raised and is at the mowing end position, the mowing part G is in a rotating state, and at least a predetermined time after the mowing is completed, that is, a time required for the mowing grain culm to be transported through the mowing part G has elapsed. However, when the stock switch S0 has not changed from the ON state to the OFF state, it is determined that the stock switch S0 has an ON failure. On the other hand, when the mowing part G is at the mowing position, the mowing part G is in a rotating state, and at least a predetermined time after the start of rotation, that is, even when a time required for the mowing grain culm to be transported through the mowing part G has elapsed. When the stock switch S0 has not changed from the OFF state to the ON state, it is determined that the stock switch S0 has an OFF failure.

In the above embodiment, the power unit is constituted by the diesel engine E. However, the power unit may be constituted by a gasoline type internal combustion engine or an electric motor operated by a battery. In addition, the power generation means also includes the engine E
It is not limited to the rotation speed sensor (engine rotation speed detection sensor S4) for detecting the rotation speed of the output shaft of (1).

In the above embodiment, the working device is the threshing device 2
The power on / off means for the threshing device 2 is
4 shows an example in which the on / off state detecting means is constituted by the threshing switch S3, but a cutting unit G or the like other than the threshing device 2 may be used as a working device. In this case, the power on / off means is a cutting clutch. In addition, the on / off state detecting means is configured as a mowing switch. The power on / off means is not limited to the clutch.

In the above embodiment, when the working device is the threshing device 2, the work detecting means is constituted by the screw rotation speed detecting sensor S5 for detecting the rotation speed of the second screw 9, but other than this, for example, A rotation speed detection sensor that detects the rotation speed of the screw 28 first may be used. Further, when the working device is the cutting unit G, for example, a sensor that detects the number of rotations of the conveying devices 6 and 8 that convey the cut culm can be used as the work detecting means.

In the above-described embodiment, an example in which the present invention is applied to a combine as a work vehicle is illustrated. However, the present invention can be applied to various work vehicles other than the combine.

Incidentally, reference numerals are written in the claims for convenience of comparison with the drawings, but the present invention is not limited to the configuration of the attached drawings by the entry.

[Brief description of the drawings]

FIG. 1 is a block diagram of a control configuration.

FIG. 2 is a side view of the combine.

FIG. 3 is a side perspective view of the threshing apparatus.

FIG. 4 is a system diagram showing power transmission.

FIG. 5 is a flowchart of a control operation.

FIG. 6 is a flowchart of a control operation.

FIG. 7 is a graph of threshing control characteristics

FIG. 8 is a specific configuration diagram of a volume sensor.

FIG. 9 is a configuration diagram for detecting a failure of a volume sensor according to another embodiment.

FIG. 10 is a flowchart for detecting a failure of a sensor according to another embodiment.

[Explanation of symbols]

 E Power device 2 Working device 14 Power on / off means S3 On / off state detecting means C Control means S4 Power generation detecting means S5 Work detecting means

──────────────────────────────────────────────────続 き Continued on the front page (72) Tamaki Naka, 64 Ishizukita-cho, Sakai City, Osaka Prefecture Inside Kubota Sakai Factory (72) Inventor, Masaru Kawane 64, Ishizukitacho, Sakai City, Osaka Prefecture Kubota Sakai Co., Ltd. Inside the factory (72) Inventor Yasunori Nishiyama 64 Ishizukita-cho, Sakai-shi, Osaka Kubota Sakai Factory Co., Ltd. (56) References JP-A-62-1881 (JP, Y2) JP-A-3-45555 (JP, Y2) (58) Field surveyed (Int. Cl. ⁶ , DB name) A01F 12/56 A01D 69/00

Claims (2)

(57) [Claims] 1. A power unit (E), and the power unit (E)
Working device (2) driven by the power of the above, power on / off means (14) for turning on / off the power transmission from the power device (E) to the working device (2), and the power on / off means (14) ON / OFF state detecting means (S
3) and a control device for a work vehicle provided with control means (C) for controlling the operation of the work device (2), wherein power generation detection means for detecting generation of power of the power device (E). (S4), and a work detecting means (S5) for detecting the operation of the working device (2) are provided. The control means (C) includes the power generation detecting means (S4) and the work detecting means (S
5) Based on the information of the on / off state detection means (S3), the on / off state detection means (S3) determines whether the power transmission is on.
Judge whether it is an ON failure that is fixed in the state to be detected
ON failure determination processing and on / off state detection means (S3)
Is fixed in the state of detecting the cutoff of the power transmission.
And an off-failure determination process for determining whether a failure has occurred.
A work vehicle control device configured to determine whether or not the on / off state detection means (S3) is out of order by execution . 2. The working device (2) is configured to control the operation device (2) when the on / off state detection means (S3) is not faulty and when the on / off state detection means (S3) is in an on state.
2. The control device for a work vehicle according to claim 1, wherein the control for the work vehicle is not started when the on / off state detection means (S3) is out of order. .