JP2001182101A - Switch operation of service car - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem of operation which is not easy, because the number of levers is too many, even through fine operations can be conducted due to the levers corresponding to each application being installed to a conventional service car. SOLUTION: In the service car, mode switches capable of selecting an operation mode or a nonoperation mode are mounted, and traveling speed in the case of operation and the PTO rotating speed are determined simultaneously by selecting the mode switches. In the nonoperation mode, traveling speed and a change gear ratio corresponding to the rotation of an accelerator pedal are determined, a traveling speed in the case of operation determined by selecting the mode switches is constituted in a changeable manner by a speed-adjusting means, and the speed-adjusting means is constituted of the accelerator pedal as an accelerating means and a brake pedal as a decelerating means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a traveling operation and a working operation of a working vehicle such as a tractor, and more particularly to a switch operation for changing a vehicle speed or a working machine driving state in accordance with a traveling operation or a working state. The object of the present invention is to reduce the burden on the user and to enable a comfortable operation with a simple operation.

[0002]

2. Description of the Related Art Conventionally, in a working vehicle such as a tractor,
Various types of operation levers are arranged on an operation unit near a seat where an operator is located. For example, a main shift lever and a sub-shift lever for performing a traveling shift, a reversing lever for switching between forward and backward traveling, an accelerator lever (pedal), a brake pedal, and the like are provided. Further, a PTO clutch lever, a PTO shift lever, and the like for operating a work machine connected to the traveling vehicle are provided. When traveling, the main transmission lever and the sub transmission lever are operated to change the traveling speed. At the time of work, the main transmission lever and the sub transmission lever are also operated to perform the traveling speed shift according to the work state. In order to change the driving speed of the working machine and the PTO clutch for connecting and disconnecting the drive to the working machine, the user has been working while operating the PTO shift lever.

[0003]

In the above prior art, since the levers corresponding to the respective applications are provided, it is possible to perform a fine operation, but on the other hand, the number of levers is too large. However, there is a problem that operation becomes difficult. Also, in actual work, the appropriate vehicle speed and work machine drive speed according to the work state are roughly determined, so even if the above-mentioned levers are not finely operated, the vehicle speed and work machine drive suitable for the work state If the speed is obtained immediately, the work efficiency will be greatly improved, the burden on the operator will be reduced,
Work comfort will also be improved.

[0004]

The above is the problem to be solved by the present invention. Next, means for solving the problem will be described. That is, in the work vehicle, a mode switch capable of selecting a work mode or a non-work mode is provided.

[0005] Further, the running speed at the time of work is determined by selecting the mode switch.

According to a third aspect of the present invention, the PTO rotation speed during operation is determined by selecting the mode switch.

According to a fourth aspect of the present invention, the traveling speed and the PTO rotation speed during operation are determined simultaneously by selecting the mode switch.

According to a fifth aspect of the present invention, in the non-operation mode, the traveling speed is determined according to the rotation of the accelerator pedal.

According to a sixth aspect of the present invention, in the non-working mode, the running speed is changed in conjunction with the rotation of the accelerator pedal.

Further, according to a seventh aspect of the present invention, the traveling speed during the work determined by the selection of the mode switch can be changed by speed adjusting means.

Further, the speed adjusting means is constituted by an accelerator pedal as a speed increasing means and a brake pedal as a speed reducing means.

Further, when the mode switch of the work mode is selected and the PTO clutch is connected, an alarm sound is generated.

According to a tenth aspect of the present invention, in the non-working mode, the functions of automatic braking, front wheel acceleration, and back elevation are limited.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a schematic diagram showing a drive system of a work vehicle, FIG. 2 is a configuration diagram of a switch operation system according to the present invention,
FIG. 3 is a view showing one embodiment of the operation unit, and FIG. 4 is a view showing one embodiment of the display panel.

First, a schematic configuration of a working vehicle, which is an embodiment provided with a mode switch according to the present invention, will be described with reference to FIG. The work vehicle transmits the output of the engine 1 from the engine output shaft 1a to a hydraulic continuously variable transmission 2 (hereinafter, referred to as HST2) which is a continuously variable transmission. In this embodiment, the HST is used as the continuously variable transmission, but a configuration may also be adopted in which a belt continuously variable transmission (CVT) or the like is mounted.

The HST 2 comprises a variable displacement hydraulic pump 21 and a hydraulic motor 22. By tilting the movable swash plates 21a and 22a, the pump discharge amount and the motor output are changed, and The engine output input to the device 3 is shifted.

The movable swash plate 21a is provided with a forward electromagnetic proportional valve 12 and a reverse electromagnetic proportional valve 13, which will be described later. The movable swash plate 21a is moved forward by operating the respective electromagnetic proportional valves 12 and 13. The hydraulic oil is tilted to the side or the reverse side to control the direction and flow rate of the hydraulic oil flowing into and out of the hydraulic motor 22. The movable swash plate 22a is provided with a motor electromagnetic proportional valve 14, and the motor electromagnetic proportional valve 14 is provided.
4, the movable swash plate 22a is tilted, and the rotational speed of the hydraulic motor 22, which is rotationally driven by the inflow and outflow of hydraulic oil from the hydraulic pump 21, is changed. That is,
The vehicle speed is mainly shifted by the tilting operation of the movable swash plate 21a, and the auxiliary speed is changed by the tilting operation of the movable swash plate 22a.

The engine output shifted in the HST 2 is transmitted to front and rear differentials 4a and 5a disposed in front of and behind the work vehicle via a transmission device 3, and transmitted to the front and rear wheels 4.5 via an axle. Drive. In addition,
In the present embodiment, the HST 2 is of a variable displacement type for both the hydraulic pump and the motor, but it may be configured such that either one is of the variable displacement type. Further, a configuration in which only the rear wheel 5 is driven may be employed.

Further, the engine output shaft 1a extends through the hydraulic pump 21 and extends into the transmission device 3, and after passing through the PTO clutch 6 and the PTO transmission 7 in the transmission device 3, the engine output shaft 1a is connected to the PTO shaft 8a. Connected. In such a configuration, the engine output is the PTO transmission 7
After that, the work machine 8 connected to the end of the PTO shaft 8a is driven.

Next, the overall configuration of the switch operation system according to the present invention will be described with reference to FIGS. The control means 10, which is the main controller of the switch operation system, has a CP
U, storage means, etc., and switches, sensors, actuators and the like of each operation system are connected, and the switch operation system according to the present invention is controlled by a control program.

The accelerator pedal 50 is provided with an angle sensor 50s for detecting the turning angle of the pedal, and the brake pedal 51 is also provided with an angle sensor 51s for detecting the turning angle of the pedal. The control means 10 is connected to the accelerator / brake pedal 50.
The stepping state of 51 is constantly sensed.

The reversing lever 52 is provided with a reversing switch 52s.
Are connected to the control means 10 and the reverser lever 52
(F), neutral (N), and reverse (R) switching by the operation of.

An electronic governor controller 11 is connected to the control means 10 and controls the number of revolutions of the engine 1 in accordance with a control command from the control means 10. The electromagnetic proportional valve 12 for forward movement, the electromagnetic proportional valve 13 for reverse movement, and the electromagnetic proportional valve 14 for motor,
, Respectively, according to the control command of the control means 10,
The swash plate angles of the hydraulic pumps / motors 21 and 22 are controlled.
The traveling speed changing means is constituted by the electronic governor controller 11 and the electromagnetic proportional valves 12, 13 and 14 which are the speed change actuators described above.

The PTO clutch 6 and the PTO transmission 7 are provided with proportional solenoid valves 16 and 17, respectively, and are connected to the control means 10, respectively. Then, in accordance with an instruction from the control means 10, by operating the electromagnetic proportional valve 16, the on / off operation of the PTO clutch 6 is performed, and the connection / disconnection of the engine output to / from the PTO shaft 8a is performed. Also, the electromagnetic proportional valve 1
By operating the PTO transmission 7, the PTO transmission 7 is switched to a multi-stage (three stages in this embodiment), and the PTO shaft 8 is switched.
The rotation speed of a is controlled.

Next, a method of controlling the traveling speed by the switch operation system will be described. As shown in FIG. 3, the operation unit 30 is provided with a plurality of mode switches corresponding to a work mode and a non-work mode. In this embodiment, the mode switches are a road running switch 31a, a rough switch 32a, a fine earth switch. 32b, scratch switch 32
A switch of four modes c is provided. As will be described later, the mode switch enables the vehicle speed to be increased / decreased and the driving state of the working machine to be changed only by operating the switch. In the present invention, the conventional speed change lever, auxiliary speed change lever, PTO speed change A simple operation by a switch operation is enabled without any levers such as a lever. The operation unit 30 is arranged near the driver's seat of the work vehicle, and is arranged so that the operator can operate the switch while operating the steering wheel.

Of the mode switches, three switches, a roughing / small soil / scratch switch 32a, 32b and 32c, are defined as a work mode switch 32, and a road running switch 31a is defined as a non-work mode switch 31. The work mode is a state in which the work machine 8 connected to the work vehicle is driven, and the non-work mode is a state in which the work machine 8 is stopped, that is, when the work vehicle travels on the road (moving travel). Mode.

Then, as shown in FIG. 2, running on the road, roughing, fine earth, and scraping switches 31a, 32a, 32b, 3
2c are connected to the control means 10, respectively. Also,
The control means 10 is provided with a set speed storage means 60. The set speed storage means 60 has a speed ratio of the HST2 and an engine corresponding to the mode of the rough / small / scratch switch 32a / 32b / 32c. The number of rotations of 1 is stored.

In such a configuration, if any of the mode switches of the roughing / small soil / scratching switches 32a, 32b and 32c is selected, the control means 10 stores the respective speeds in the set speed storage means 60. The gear ratio and the engine speed corresponding to the mode are acquired, and the tilt angle of the swash plate is instructed to the forward electromagnetic proportional valve 12, the reverse electromagnetic proportional valve 13, or the motor electromagnetic proportional valve 14 according to the set values. Then, the shift of HST2 is performed, and an instruction is sent to the electronic governor controller 11 to adjust the engine speed to the set value.

That is, when the speed ratio acquired by the set speed storage means 60 is the forward speed ratio (normally, when performing work, the speed is forward, so the forward speed ratio is set. In (), the main shift is performed by operating the electromagnetic forward proportional valve 12 to change the discharge amount of the hydraulic pump 21. Further, if necessary, the motor proportional solenoid valve 14 may be used.
Is operated to change the rotational drive of the hydraulic motor 22 to perform the sub-shift. Similarly, when the speed ratio acquired from the set speed storage means 60 is the reverse speed ratio, the reverse gear ratio is operated by operating the reverse electromagnetic proportional valve 13 and the motor proportional valve 14. . In this embodiment, since the initial setting of the operation mode is the maximum engine speed, the roughing / small soil / scratch switch 3 is used.
When any one of the mode switches 2a, 32b, and 32c is selected, the control unit 10 controls the electronic governor controller 11 to maximize the engine speed.

On the other hand, when the on-road switch 31a is selected, the control means 10 changes the vehicle speed according to the operation amount of the accelerator pedal 50. That is, the control means 1
0 calculates the target speed of the work vehicle from the detected value of the angle sensor 50s, and in order to achieve this target speed, the electromagnetic actuator proportionally moving valve 12, the electromagnetic proportional valve 14 for the motor, and the electronic governor controller 11 is operated. When the reverser lever 52 is switched to the reverse (R) side, the accelerator pedal 50 is operated by operating the reverse electromagnetic proportional valve 13, the motor electromagnetic proportional valve 14, and the electronic governor controller 11. The reverse shift is performed according to the amount. When the reverser lever 52 is operated to the neutral (N) position, the speed change actuators 12, 13, 14
Is controlled at the neutral position. That is, the movable swash plates 21a and 22
When a is tilted to the neutral position, the drive to the front and rear wheels is stopped.

As described above, in the work vehicle according to the present invention, since a plurality of selectable mode switches corresponding to the work mode and the non-work mode are provided near the driver's seat of the work vehicle, the shift lever and the like are operated. The mode can be switched between the work mode and the non-work mode by a switch operation without any operation, and the configuration is excellent in operability. Further, since the configuration is such that the traveling speed during work is determined by selecting the mode switch, the operator selects the switch without operating a plurality of shift levers (main shift lever, sub shift lever, etc.) as in the related art. With just a simple operation, an appropriate speed can be obtained according to the work application.

The mode switch is provided with four modes of driving on the road, rough running, fine soil, and sowing in the operation unit 30, and the set speed ratio and the engine speed corresponding to each mode are stored and held. So the operator
The desired vehicle speed can be obtained by selecting the mode switch corresponding to the name of each work instead of numerical values such as speed and second speed, so that the operation method is clear and malfunction can be prevented, and operability has been improved. .

In this embodiment, three working mode switches 32 and one non-working mode switch 31 are provided.
Is provided in the operation unit 30, but the configuration is not limited to the present embodiment, and the configuration may be such that four or more work mode switches 32 are used to hold fine settings according to the work application. And narrow down the work application 2
It is also possible to adopt a configuration in which emphasis is placed on simple operations.

Next, an interlocking structure between the shift switch, the PTO clutch 6 and the PTO transmission 7 will be described. When the on-road running / roughing / small / scratch switch 31a / 32a / 32b / 32c of the operation unit 30 is selected, the control means 10 increases and decreases the vehicle speed as described above, The control is also performed.

As shown in FIG. 2, the control means 10 has a PTO setting storage means 61 for storing the set speed (the gear position of the PTO shaft) of the work machine 8 in accordance with the roughing, fine soil and substitute scraping modes. Electromagnetic proportional valves 16 and 17 are connected to the control means 10 to switch the PTO clutch 6 and the PTO transmission 7, respectively. When the mode switch is selected, the control device 10 instructs the traveling speed changing means to increase or decrease the vehicle speed, and also instructs the electromagnetic proportional valves 16 and 17 to perform the PTO shift / PT
An instruction to connect and disconnect the O-clutch is issued.

Here, when the selected mode switch is the road operation switch 31a in the non-work mode,
An instruction to turn off the PTO clutch 6 is given by the electromagnetic proportional valve 16.
Send to In addition, the selected mode switch is the work mode roughing / fine soiling / scratching switch 32a / 32b / 32
c, the corresponding PTO speed is obtained from the PTO setting storage means 61, and P
An instruction to shift the TO transmission 7 is issued, and an instruction to make the PTO clutch 6 “connected” is sent to the electromagnetic proportional valve 16. In other words, roughing, fine earth, slash switch 32a
Work mode switch 32 composed of 32b and 32c
Is a switch for increasing / decreasing the vehicle speed, and at the same time, has a function as a connection / disconnection of a work machine and a shift switch.

For example, in this embodiment, when the roughing switch 32a is selected, the vehicle speed is reduced to approximately 0.5 m.
/ S, the PTO transmission 7 is shifted to the first speed, and when the fine earth switch 32b is selected, the vehicle speed is set to approximately 0.3 m / s and the PTO transmission 7 is set to the second speed. When the shift switch 32c is selected, the vehicle speed is set to approximately 0.7 m / s, and
That is, the TO transmission 7 is controlled to shift to the second speed.

As described above, in the switch operation according to the present invention, the configuration is such that the PTO rotation speed at the time of work is determined by the selection of the mode switch. A PTO rotation speed suitable for the state was obtained, and operability was improved. In addition, since the traveling speed and the PTO rotation speed at the time of the work are simultaneously determined by selecting the mode switch, the operation procedure of the operator is greatly simplified, and the stable work becomes possible.

As described above, the operation of the conventional work vehicle is performed while making full use of the main shift lever, the auxiliary shift lever, and the like.
In order to adjust the traveling speed and adjust the working machine 8 to an appropriate driving state, the working machine is shifted by the PTO shift lever. In addition, the power transmission to the working machine 8 must be turned on and off by the PTO clutch lever. However, according to the switch operation system of the present invention, all of these lever operations can be performed by one switch operation, and the operability has been significantly improved. Further, since the mode switch is given a name according to the work application, the operation is clear and malfunction can be prevented.

Further, in the present invention, when the mode switch of the operation mode is selected and the PTO clutch 6 is connected, an alarm sound is generated. By adopting such a configuration, the operator and the persons in the vicinity can know that the PTO shaft is driven, so that it is possible to explicitly recognize the start of driving of the work machine 8 and prevent erroneous operation. Made it possible.

Next, a method of using and controlling the accelerator pedal 50 and the brake pedal 51 in the work mode and the non-work mode according to the present invention will be described.
First, a case where the work mode switch 32 is selected will be described. As described above, the work mode switch 32
Is selected, the set speed storage means 60
The vehicle speed is automatically determined based on the set speed ratio and the engine speed corresponding to each switch stored in the switch.
Hereinafter, traveling at this set speed is referred to as automatic traveling.

When the operator does not like the set speed or wants to change the speed to a more optimum speed, he operates the accelerator pedal 50 and the brake pedal 51 as speed adjusting means to change the speed. It is possible to do it. Specifically, when the operator depresses the accelerator pedal 50 in the automatic driving state, the control means 10 sends a control command to the speed change actuator based on the detection value of the angle sensor 50s to increase the speed ratio of the HST2. Or electronic governor controller 1
1 to increase the number of revolutions of the engine 1. Conversely, when the brake pedal 51 is depressed, the speed ratio of the HST 2 is reduced or the rotation speed of the engine 1 is reduced based on the detection value of the angle sensor 51s.

That is, a control command is sent to the forward electromagnetic proportional valve 12 (or the backward electromagnetic proportional valve 13) and the motor electromagnetic proportional valve 14 based on the detected value of the angle sensor 50s or the angle sensor 51s. Then, based on this control command, the swash plates of the movable swash plates 21a and 22a of the hydraulic pumps / motors 21 and 22 are tilted by the respective electromagnetic proportional valves 12, 13 and 14. The control means 10 sends a control command to the electronic governor controller 11 based on the detected value of the angle sensor 50s or the angle sensor 51s,
Is controlled to the target rotation speed.

As described above, in the work mode, the engine speed is normally set as the maximum speed, so that the HST2 is operated by operating the speed change actuator to increase the vehicle speed from the set speed. Will be increased. However, if the operator has made a setting change to decrease the engine speed, or if the engine speed is reduced by depressing the brake pedal 51, the shift speed and the electronic governor controller 11 are operated to reduce the target speed. Control it to get it.

As described above, in the switch operation system according to the present invention, the running speed according to the rotation of the accelerator pedal 50 is determined in the non-working mode as described above. Thus, a general-purpose structure with good maneuverability is provided, and the running speed is changed in accordance with the rotation of the accelerator pedal 50. Therefore, the speed change according to the vehicle speed is automatically performed, and stable running is possible. On the other hand, in the work mode, the running speed can be increased / decreased by operating the accelerator pedal 50 and the brake pedal 51, which are speed adjusting means, while enabling easy operation by automatic running, thereby flexibly responding to the demands of the operator. It became possible.

In the present invention, when the mode switch in the non-working mode is selected, that is, when the on-road drive switch 31a is selected, functions such as automatic braking, front wheel acceleration, and back-up are limited. I am trying to be. In tilling work of tractors, etc., automatic braking and front wheel speed-up functions are used to perform turning operations with a small radius, but these functions are not activated during road running, enabling stable road running. This prevents unexpected operation by the operator. Further, in the conventional working vehicle, when the shift lever or the like is operated to the reverse side, the working machine 8 is raised, but in the non-working mode according to the present invention, during work such as garage parking. In order to prevent the work machine 8 from rising, the back lifting function is also limited.

FIG. 4 shows a display panel 40 for visually grasping the state of the switch operation system. Display panel 40
Is arranged at the front of the operation unit to make it easy for the operator to check the operation status while running and working. On the display panel 40, a plurality of confirmation lamps 41 to 4 are provided.
9 are arranged, and these confirmation lamps 41 to 49 are connected to the control means 10 as shown in FIG.

When the mode switch of the working mode / non-working mode is selected, the corresponding mode confirmation lamps 41 to 44 are turned on. Are turned on. As described above, the easy operation is realized by the switch operation of the operation unit 30, and the display panel 40 is configured so that the operator can easily visually confirm the operation state, thereby improving the operability.

[0049]

As described above, the present invention has the following advantages. That is, in the work vehicle, the work vehicle is provided with the mode switch capable of selecting the work mode and the non-work mode, so that the mode can be switched between the work mode and the non-work mode by operating the switch without operating the shift lever or the like. Thus, the configuration was excellent in operability.

Further, since the traveling speed during the operation is determined by selecting the mode switch, the operator can use a plurality of shift levers (main shift lever, sub shift lever) as in the prior art. Etc.), and a simple operation of selecting a switch can be performed to obtain an appropriate speed according to the application of the work.

Further, the operability is improved because the PTO rotation speed at the time of work is determined by selecting the mode switch.

Further, since the running speed and the PTO speed during the operation are determined simultaneously by selecting the mode switch, the operation procedure of the operator is greatly simplified. Stable work became possible.

Further, in the non-working mode, the running speed is determined in accordance with the rotation of the accelerator pedal, so that the operation is the same as that of a passenger car, and the operation is versatile and versatile. It became a good configuration.

In the non-working mode, the running speed is changed in conjunction with the rotation of the accelerator pedal, so that the speed is automatically changed according to the vehicle speed and the running speed is stabilized. Became possible.

Further, since the traveling speed during the work determined by the selection of the mode switch can be changed by the speed adjusting means, an easy operation by the switch operation is made possible while the operator operates the switch. It became a configuration that can flexibly respond to requests.

Further, since the speed adjusting means is constituted by an accelerator pedal which is a speed increasing means and a brake pedal which is a decelerating means, the speed adjusting means is constituted by using existing parts. Thus, the configuration is excellent in operability and cost.

Further, when the PTO speed is other than neutral, an alarm sound is generated, so that the operator and persons in the vicinity can know that the PTO shaft is driven. Therefore, it is possible to explicitly recognize the start of driving of the work machine, thereby preventing erroneous operation.

In the non-working mode, the functions of automatic braking, front wheel acceleration, and back-up are limited, so that unexpected operations by the operator can be prevented and stable operation can be achieved. Road driving is now possible.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a drive system of a work vehicle.

FIG. 2 is a configuration diagram of a switch operation system according to the present invention.

FIG. 3 is a view showing an embodiment of an operation unit.

FIG. 4 is a diagram illustrating an example of a display panel.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine 2 HST 6 PTO clutch 7 PTO transmission 8 Work implement 10 Control means 11 Electronic governor control 12 Electromagnetic proportional valve for forward 13 Electromagnetic proportional valve for reverse 14 Electromagnetic proportional valve for motor 16 Electromagnetic proportional valve 17 Electromagnetic proportional valve 21 (HST ) Hydraulic pump 22 (HST) hydraulic motor 30 Operating unit 31 Non-work mode switch 31a Road running switch 32 Work mode switch 32a Roughing switch 32b Fine earth switch 32c Substitution switch 40 Display panel 50 Accelerator pedal 51 Brake pedal

Continued on the front page F term (reference) 2D003 AB01 AB06 BA01 BA03 BA07 BB07 CA02 DA04 DB04 FA02 3D040 AA10 AA22 AA35 AA40 AB04 AC02 AC49 AC50 AD12 AD13 AD19 3D042 AA01 AB12 BA02 BA08 BD04

Claims (10)

[Claims] 1. A switch operation of a work vehicle, wherein the work vehicle is provided with a mode switch capable of selecting a work mode or a non-work mode. 2. The switch operation of a work vehicle according to claim 1, wherein a traveling speed during work is determined by selecting the mode switch. 3. The switch operation of a work vehicle according to claim 1, wherein a PTO rotation speed during operation is determined by selecting the mode switch. 4. The switch operation of a work vehicle according to claim 1, wherein a running speed and a PTO rotation speed during work are determined simultaneously by selecting the mode switch. 5. The switch operation of a work vehicle according to claim 1, wherein in the non-work mode, a traveling speed according to rotation of an accelerator pedal is determined. 6. The switch operation of a work vehicle according to claim 1, wherein in the non-work mode, the running speed is changed in conjunction with rotation of an accelerator pedal. 7. The switch operation of a work vehicle according to claim 2, wherein a traveling speed at the time of work determined by selection of the mode switch can be changed by speed adjusting means. 8. The switch operation of a work vehicle according to claim 7, wherein said speed adjusting means is constituted by an accelerator pedal as a speed increasing means and a brake pedal as a speed reducing means. 9. The switch operation of a work vehicle according to claim 3, wherein an alarm sound is issued when the mode switch of the work mode is selected and the PTO clutch is connected. 10. The switch operation of a work vehicle according to claim 1, wherein in the non-work mode, the functions of automatic braking, front wheel speed increase, and back ascent are limited.