JPH061121U - Switching mechanism for four-wheel steering system for agricultural vehicles - Google Patents

Abstract

(57) [Abstract] [Purpose] An agricultural vehicle equipped with a four-wheel steering device is automatically switched to a two-wheel steering state when traveling on the road to avoid the danger of a sharp turn. [Structure] A switch for switching between a four-wheel steering state and a two-wheel steering state is interlocked with a main gear shift lever of an agricultural vehicle so that a four-wheel steering state is set when traveling on a field and a two-wheel steering state is set when traveling on a road.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a means for switching a four-wheel steering device for agricultural vehicles such as rice transplanters and chemical sprayers (speed sprayer) to a four-wheel steering state when traveling in the field and a two-wheel steering state when traveling on the road.

[0002]

[Prior art]

 In an agricultural vehicle equipped with a four-wheel steering system, when traveling in the field at a relatively low speed, the front wheels and the rear wheels are steered in opposite phases so that a steerable turn can be made and high speed is achieved. When traveling on the road, a means for switching to a two-wheel steering state in which only the front wheels are steered is adopted.

[0003]

[Problems to be solved by the device]

 However, if the above switching is forgotten, the front and rear wheels may be steered by the four wheels in opposite phases when driving on the road at high speed, which may cause a sharp turn, which is dangerous. Therefore, the purpose of this plan is to automatically switch to the two-wheel steering state when driving on the road to avoid the above danger.

[0004]

[Means for Solving the Problems]

 Therefore, a switch for switching between the four-wheel steering state and the two-wheel steering state is linked to the main shift lever of the agricultural vehicle, so that the four-wheel steering state is set when traveling on the field and the two-wheel steering state is set when traveling on the road.

[0005]

[Action]

 When the main gear shift lever of the agricultural vehicle is driven on the road, the switch is switched and the four-wheel steering state is switched to the two-wheel steering state.

[0006]

Embodiments Embodiments of the present invention will be described below. FIG. 1 is a perspective view of an agricultural vehicle, in which 1 is a front wheel and 2 is a rear wheel. A steering 4 is provided in front of the driver's seat 3, and a main transmission lever 5 is provided beside the driver's seat 3. As shown in FIG. 2, the main speed change lever 5 can be operated along the guide groove 6, and when the main speed change lever 5 is in the neutral position is when working on the agricultural vehicle, and is pushed forward. Time is when driving on the road, and when being pulled backward is when moving backward. A switch 7 is arranged at the front end of the guide groove 6 as described above, and when the main transmission lever 5 is pushed forward to switch to traveling on the road, the switch 7 is turned on and steering is performed via the cable 8. An ON signal is input to the control device 9. Further, a steering signal from the steering wheel 4 and a signal from a manual selector switch 10 for manually switching between a four-wheel steering state and a two-wheel steering state are input to the steering control device 9.

FIG. 3 shows a hydraulic pressure supply circuit for steering the front wheels 1 and the rear wheels 2, and 11 is a pump for supplying pressure oil. Pressure oil is supplied to the left chamber 13 and the right chamber 14 of the power steering cylinder 12 of the front wheel 1 via a control valve 15, and the control valve 19 is provided to the left chamber 17 and the right chamber 18 of the power steering cylinder 16 of the rear wheel 2. Pressure oil is supplied via The electromagnetic solenoids of the control valves 15 and 19 are controlled by the steering control device 9 described above. In the four-wheel steering state, both control valves 15 and 19 are activated, and in the two-wheel steering state. Only the control valve 15 of the front wheel 1 is activated.

By the way, when the main gear shift lever 5 is in the neutral position and the vehicle is traveling in the field, the switch 7 is not pushed and is in the OFF state. When the steering wheel 4 is steered during traveling in such a field, the electromagnetic solenoids of both the control valves 15 and 19 of the front wheels 1 and the rear wheels 2 are activated by the signal from the steering control device 9, and the front wheels 1 and the rear wheels 2 are operated. Steers are made in opposite phases and a sharp turn is made. On the other hand, when the main transmission lever 5 is pushed forward to switch to traveling on the road, the switch 7 provided at the front end of the guide groove 6 is turned on, and an ON signal is input to the steering control device 9 via the cable 8. . As a result, when the steering is switched to the two-wheel steering state and the steering ring 4 is steered, only the electromagnetic solenoid of the control valve 15 of the front wheel 1 operates, and the control valve 19 of the rear wheel 2 does not supply hydraulic pressure. As a result, only the front wheels 1 are steered, and a sharp turn is not made. It should be noted that the switching between the four-wheel steering state and the two-wheel steering state associated with the operation of the main transmission lever 5 as described above is performed with priority over the manual changeover switch 10.

[0009]

[Effect of device]

 According to the switching mechanism of the present proposal, the two-wheel steering state is automatically switched when traveling on the road, so there is no concern that the operator forgets to switch and makes a sharp turn at high speed, which is safe.

[Brief description of drawings]

FIG. 1 is a perspective view of an agricultural vehicle.

[Fig. 2] Relational diagram of main shift lever and switch

FIG. 3 is a hydraulic pressure supply circuit diagram of the steering device.

[Explanation of symbols]

 5 Main shift lever 7 Switch

Claims (1)

[Scope of utility model registration request] 1. A configuration in which a switch for switching between a four-wheel steering state and a two-wheel steering state is interlocked with a main gear shift lever of an agricultural vehicle so as to switch to a four-wheel steering state when traveling on a field and to switch to a two-wheel steering state when traveling on a road. Switching mechanism for four-wheel steering system for agricultural vehicles.