JPH0459576U

JPH0459576U -

Info

Publication number: JPH0459576U
Application number: JP10304390U
Authority: JP
Priority date: 1990-09-29
Filing date: 1990-09-29
Publication date: 1992-05-21

Description

[Brief explanation of the drawing]

第１図は本考案による自走式作業車両の四輪操
舵装置の全体構成図である。第２図はその処理手
順を示すフローチヤートである。第３図は動作を
説明する図である。第４図は従来例を示す全体構
成図である。１……油圧ポンプ、２……エンジン、３……ス
テアリングバルブ、４……ステアリングハンドル
、９Ｒ，９Ｌ……前輪ステアリングシリンダ、１
０Ｒ，１０Ｌ……後輪ステアリングシリンダ、１
３Ｒ，１３Ｌ……前輪、１４Ｒ，１４Ｌ……後輪
、３１……電磁切換弁、３２……コントローラ、
Ｓ１……前輪ストロークエンド検出用センサ、Ｓ
２……後輪中立位置検出用センサ、ＳＲ，ＳＬ，
ＳＭ……検出板、ＰＲ，ＰＬ……圧力スイツチ。 FIG. 1 is an overall configuration diagram of a four-wheel steering system for a self-propelled work vehicle according to the present invention. FIG. 2 is a flowchart showing the processing procedure. FIG. 3 is a diagram explaining the operation. FIG. 4 is an overall configuration diagram showing a conventional example. 1... Hydraulic pump, 2... Engine, 3... Steering valve, 4... Steering handle, 9R, 9L... Front wheel steering cylinder, 1
0R, 10L...Rear wheel steering cylinder, 1
3R, 13L...front wheel, 14R, 14L...rear wheel, 31...electromagnetic switching valve, 32...controller,
S1...Front wheel stroke end detection sensor, S
2... Sensor for detecting rear wheel neutral position, SR, SL,
SM...Detection plate, PR, PL...Pressure switch.

Claims

[Scope of Claim for Utility Model Registration] 1. A single hydraulic pump, a front wheel steering cylinder and a rear wheel steering cylinder operated by the oil discharged from this hydraulic pump, and a flow rate of pressure oil from the hydraulic pump according to the operation of the steering handle. A four-wheel steering system for a self-propelled work vehicle, comprising a steering valve capable of supplying pressure oil to the front and rear wheel steering cylinders by controlling the direction and the direction of the steering wheel, a switching valve that is provided and can be switched between a first position for supplying pressure oil to the front wheel steering cylinder and a second position for supplying pressure oil to the rear wheel steering cylinder; and detecting a neutral position of the rear wheel steering cylinder. and a valve drive control means for switching and driving the switching valve to a first position so as to send oil discharged from the hydraulic pump to the front wheel steering cylinder while the neutral position is detected by the neutral detection means. A four-wheel steering device for a self-propelled work vehicle, comprising: 2. The steering system according to claim 1, further comprising a stroke end detection means for detecting a stroke end of the front wheel steering cylinder, and wherein the valve drive control means controls the hydraulic pump until the stroke end is detected by the stroke end detection means. The switching valve is held in a first position so as to send the discharged oil to the front steering cylinder, and when the stroke end is detected, the switching valve is switched to a second position so as to send the oil to the rear steering cylinder. A four-wheel steering device for a self-propelled work vehicle characterized by: 3. The steering system according to claim 2, wherein when switching from rear wheel steering to front wheel steering, the pressure oil is supplied to the front wheel steering cylinder when the neutral detection means detects that the rear wheel steering cylinder is neutral. A four-wheel steering device for a self-propelled work vehicle, characterized in that a switching valve is switched to a first position. 4. A single hydraulic pump, a front wheel steering cylinder and a rear wheel steering cylinder operated by the discharge oil of this hydraulic pump, and controlling the flow rate and direction of the pressure oil of the hydraulic pump according to the operation of the steering handle to A four-wheel steering system for a self-propelled work vehicle comprising a steering valve capable of supplying pressurized oil to front and rear wheel steering cylinders, wherein the four-wheel steering system is provided between the steering valve and the front and rear wheel steering cylinders, and is provided between the steering valve and the front and rear wheel steering cylinders to supply pressure to the front wheel steering cylinders. a switching valve that can be switched between a first position for supplying oil and a second position for supplying pressure oil to a rear steering cylinder; a stroke end detection means for detecting a stroke end of the front steering cylinder; The switching valve is held in the first position so as to send oil discharged from the hydraulic pump to the front wheel steering cylinder until a stroke end is detected by the means, and when the stroke end is detected, the oil is sent to the rear wheel steering cylinder. and valve drive control means for switching and driving the switching valve to a second position. 5. The steering system according to claim 4, further comprising neutral detection means for detecting a neutral position of the rear wheel steering cylinder, and wherein the valve drive control means is configured such that when switching from rear wheel steering to front wheel steering, the neutral detection means detects the neutral position of the rear wheel steering cylinder. A four-wheel steering system for a self-propelled work vehicle, characterized in that the switching valve is switched to a first position so that pressure oil is supplied to the front steering cylinder when a neutral state of the rear steering cylinder is detected.