JPH0475502A - Tractor hydraulic circuit switching valve device - Google Patents

Abstract

PURPOSE:To change an oil-hydraulic unit and an auxiliary working machine to a state in which both the oil-hydraulic unit and the auxiliary working machine can independently be operated in starting an engine by connecting a detecting switch for detecting the separation position of a switching valve and for performing ON- operation to a key switch for starting the engine in a series. CONSTITUTION:The first oil-hydraulic pump (P1) is connected through the first oil path 6 to a control valve 3 of an oil-hydraulic unit 2 and the second oil-hydraulic pump (P2) is connected through the second oil path 7 to an auxiliary control valve 5 of an actuator 4 of an auxiliary working machine. A switching valve 8 existing in the middle of the first oil path 6 and the second oil path 7 has a separation position (A) and a confluence position (B). The separation position (A) connects the first oil- hydraulic pump (P1) and the second oil-hydraulic pump (P2) respectively to the control valve 3 and the auxiliary valve 5. The confluence position (B) connects both the first and second oil-hydraulic pumps (P1) and (P2) to the auxiliary control valve 5. A detecting switch 14 is connected to a starter 10 and a key switch 11 in a series and the detecting switch 14 is switched on when the switching valve 8 exists at the separation position (A).

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a hydraulic circuit switching valve device for a tractor.

(Prior art) In the case of a tractor, in addition to the hydraulic system for lifting and lowering the work equipment, which is normally provided, it is necessary to operate the hydraulic equipment of the auxiliary work equipment (front loader, cane rack, etc.) that is detachably attached to the tractor. The pressure oil supply to these actuators is
It is configured such that pressure oil is supplied to each actuator from an engine-driven hydraulic pump. Then, in consideration of cases where the auxiliary work equipment requires or does not require a large flow of pressure oil, or when the hydraulic system and the auxiliary work equipment are used at the same time, for example, two hydraulic pumps can be connected via a switching valve. is connected to the control valve of the hydraulic system and the auxiliary control valve of the auxiliary work equipment, and by switching the switching valve, one hydraulic pump can be set to wtm.
A valve is being considered in which the other hydraulic pumps can be connected to the auxiliary control valve, or the pressure oil of the two hydraulic pumps can be combined and connected to the auxiliary control valve. .

(Problem to be solved by the invention!) In the conventional system described above, after using the auxiliary work machine with the switching valve in the position where the two hydraulic pumps merge, the tractor is stopped and the auxiliary work machine is removed. Thereafter, even if an attempt was made to start the tractor and operate the hydraulic system with the switching valve in the merging position, the hydraulic system would not operate, and there was a risk that the operator would misunderstand that the hydraulic system or the like was malfunctioning.

Therefore, an object of the present invention is to prevent such a situation.

(Means for Solving the Problem) The technical means taken by the present invention to achieve the above object is that the first hydraulic pump P1 and the control valve 3 of the hydraulic device 20 for lifting and lowering the work machine are connected in the first oil path 6. The second hydraulic pump P2 and the auxiliary control valve 5 for the auxiliary working machine are connected by the second oil passage 7, and the first and second oil passages Hydraulic pump P1. P2 to the control valve 3 and the auxiliary control valve 5, respectively, and an independent position A, and the first and second hydraulic pumps P1. In a tractor having a hydraulic circuit 1 equipped with a switching valve 8 having a merging position B that merges P2 and connects it to an auxiliary control valve 5, the independent position A of the switching valve 8 is detected and the ON operation is performed. A detection switch 14 is connected in series to a key switch 11 connected to a starter lO for starting the engine.

(Function) The switching valve 8 is set to the independent position A, that is, the first hydraulic pump P1.
is connected to the hydraulic system 20 control valve 3, and the second hydraulic pump P2
When the switch is placed in the position where it is connected to the auxiliary control valve 5 for the auxiliary working machine, the detection switch 14 is turned on and the starter 10 can be started by the key switch 11. Therefore, when starting the engine, the switching valve 8 is turned on. is set to the independent position A, so that the hydraulic system 2 and the auxiliary working machine can be operated independently.

Note that when the auxiliary working machine requires a large flow of pressure oil, the switching valve 8 may be switched to the merging position after the engine is started.

(Example) Hereinafter, an example of the present invention will be described based on the drawings. 1st
In the figure, numeral 1 indicates a hydraulic circuit of the tractor, numeral 2 is a hydraulic device for lifting and lowering a working machine mounted on the rear upper part of the transmission case of the tractor, and numeral 3 is a control valve for controlling this. Reference numeral 4 denotes an actuator such as a hydraulic cylinder or a hydraulic motor of an auxiliary work machine that is detachably attached to the tractor and is controlled by an auxiliary control valve 5.

Pl is a first hydraulic pump, which has a capacity suitable for the operation of the hydraulic system 2, and is connected to a control valve 3 of the hydraulic system 2 via a first oil passage 6. P2 is a second hydraulic pump, which supplies the actuator 4 of the auxiliary working machine with auxiliary v! via the second oil passage 7. i
It is connected to the lIm valve 5. Further, a switching valve 8 is interposed between the first oil passage 6 and the second oil passage 7, and this switching valve 8 has an independent value 1 [A and a merging position B. The independent position A connects the first hydraulic pump PI to the control valve 3 and the second hydraulic pump P2 to the auxiliary control valve 5, making both oil passages 6 and 7 independent. 1. Second hydraulic pump PI.

P2 are both connected to the auxiliary control valve 5 to supply a large flow rate of combined pressure oil.

Further, in FIG. 1, reference numeral 9 denotes an electric circuit for a starter starting system, which connects a starter 10 and a key switch 11 to a traveling system safety switch 12 and a PTO system safety switch 1.
3 and a detection switch 14 are connected in series. The detection switch 14 is provided on the valve body of the switching valve 8, the operating lever mechanism for operating the switching valve 8, or the connecting mechanism that interlocks and connects the switching valve 8 and the operating lever mechanism, and the switching valve 8 is in the independent position A. When the valve is in the position, it contacts the spool of the switching valve 8, the operating lever, the link of the coupling mechanism, etc., and turns on. Further, the driving system safety switch 12 is turned on when the driving system clutch is OFF, and the PTO system safety switch 13 is turned ON when the PTO system clutch is OFF.
It is something that will be done. Therefore, the traveling system and PTO system clutches are turned OFF, and the switching valve 8 is set to the independent position A.
Otherwise, the starter 10 cannot be started using the key switch 11.

(Effects of the Invention) According to the present invention, the first hydraulic pump P1 and the control valve 3 of the hydraulic device 2 for lifting and lowering the work machine are connected by the first oil passage 6, and the second hydraulic pump P2 and the control valve 3 of the hydraulic system 2 for lifting and lowering the work machine are connected. The auxiliary control valve 5 is connected to the second oil passage 7, and in the middle of these first and second oil passages 6, 7,
An independent position A where the first and second hydraulic pumps PL and P2 are connected to the control valve 3 and the auxiliary control valve 5, respectively, and a merging position where the first and second hydraulic pumps PI and P2 are merged and connected to the auxiliary control valve 5. In a tractor having a hydraulic circuit 1 having a switching valve 8 interposed therein, a detection switch 14 which is turned ON upon detecting the independent position A of the switching valve 8 is connected to a starter 10 for starting the engine. The starter 10 cannot be started by the key switch 11 unless the switching valve 8 is set to the independent position A. Therefore, when starting the tractor engine, the oil pressure must be The device 2 and the auxiliary working machine can each be operated independently, and there is no possibility of misunderstanding as in the conventional case.

[Brief explanation of drawings]

FIG. 1 shows an embodiment of the present invention, and is a simplified explanatory diagram showing a hydraulic circuit and an electric circuit of an engine starting system. 2-hydraulic system, 3-.-control valve, 5-auxiliary control valve,
6--First oil passage, 7--Second oil passage, 8-Switching valve, 1o-Starter, 11-Key switch, 14-Detection switch, PL-11 first hydraulic pump, P2--Second hydraulic pump. Patent Applicant: Ri Botamuhai 6 Co., Ltd.

Claims (1)

[Claims] (1) Connect the first hydraulic pump (P1) and the control valve (3) of the hydraulic system for lifting and lowering the work machine (2) through the first oil path (6), and connect the second hydraulic pump (P2) and the auxiliary work machine. Auxiliary control valve (5
) are connected by a second oil passage (7), and the first and second hydraulic pumps (P1
) (P2) to the control valve (3) and auxiliary control valve (5), respectively (A) and the first and second hydraulic pumps (P1).
(P2) and a merging position (B) that connects the auxiliary control valve (5) to the auxiliary control valve (5). A detection switch (14) that is turned ON upon detecting the independent position (A) of 8) is connected in series to a key switch (11) connected to a starter (10) for starting the engine. Hydraulic circuit switching valve device for tractors.