JP2807128B2 - Tractor hydraulic system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a tractor hydraulic system.

[0002]

2. Description of the Related Art A tractor provided with a hydraulic device having a lift arm is provided with a front loader (first working device) and a backhoe (second working device).
The hydraulic pressure of the tractor that is sent to the control valve (third control valve) of the hydraulic device via the control valve (first control valve) of the first working device and the control valve (second control valve) of the second working device Systems are conventionally known.

[0003]

In the tractor hydraulic system described above, the loader, the backhoe, and the hydraulic device for the three-point link have the same hydraulic system. Therefore, an excessive flow rate flows into the hydraulic device for the three-point link, There were issues such as pressure loss, rise, and shock when the implement rose.

If a priority valve is mounted to prevent this, the valve is expensive and there is a problem in terms of cost. Therefore, an object of the present invention is to make it possible to flow an appropriate amount of flow to the hydraulic device without using an expensive priority valve even if the loader, the backhoe and the hydraulic device for the three-point link are of the same hydraulic system.

[0005]

According to the present invention, a tractor 1 provided with a hydraulic device 4 having a lift arm 4A is provided with first and second working devices 2 and 3 which are operated by hydraulic pressure, and a hydraulic oil from a pump P is provided. To the first control valve 6 of the first working device 2 and the second
The following technical measures are taken in the tractor hydraulic system for sending to the second control valve 8 of the industrial device 3 and the third control valve 11 of the hydraulic device 4 in order to achieve the above-mentioned object.

That is, the present invention provides a pump
Pressurized oil by connecting the first control valve 6 and the second control valve 8
A first feed to be sent to the third control valve 11 via the second control valve 8
The first control valve 6 without passing through the control line and the second control valve 8.
And the third control valve 11 connected to the third control valve 11
It is configured to select and send to two feed lines,
Entry of the third control valve 11 in the first and second feed lines
A switching valve 15 is provided in the side circuit 14, and the switching valve 15
Return oil from the second control valve 8 at the time of the first feed line
The position for closing the control valve 11 and draining it to the tank T
Of the total flow rate of the first control valve 6 at the time of the second feed line,
A small amount is drained to the tank T via the throttle 24 and the remaining amount is set to the third.
It is configured to be switchable to a position to be sent to the control valve 11.
It is characterized by having.

[0007]

[Function] When the backhoe (second working device) 3 is mounted, the three-point link is not used. Therefore, the return from the second control valve 8 in the second working device 3 is performed via the switching valve 15. Drain the entire amount into tank T. Remove the second working device 3 from the tractor 1 and use a three-point link to move the impulse to the hydraulic device.
4 when moving up and down, etc., the first control valve 6 of the first working device 2
To the input side of the switching valve 15 and the switching valve 15
To the state shown in Fig. 1 (B), and
And sends an appropriate amount to the control valve 11 of the hydraulic system 4.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. In FIG. 6, reference numeral 1 denotes a wheel-type tractor, on which a front loader 2 as a first working device and a backhoe 3 as a second working device are mounted, and a hydraulic device 4 for a three-point link is provided.

The loader 2 is operated by a lever 5 by a first control valve 6.
Is operated by hydraulic pressure, and the backhoe 3 is
By operating the second control valve 8 by means of 7, it operates hydraulically. In FIG. 6, reference numeral 9 denotes a driver's seat, 10 denotes a safety frame, and the backhoe 3 is detachable from the tractor 1 when the impulse is mounted by a three-point link. FIG.
Referring to FIG. 4, the hydraulic device 4 includes a lift arm 4A, includes a lift arm 4A by sending pressure oil to a piston fitted to the hydraulic cylinder by a control valve 11, and is fitted to the hydraulic cylinder by the control valve 11. The lift arm 4A is raised and lowered by sending pressure oil to the piston, which is mounted on the rear of the vehicle body 1A.

The control valve 6 of the loader 2, the control valve 8 of the backhoe 3, and the third control valve 11 of the hydraulic device 4 are provided in the same hydraulic system as follows. As shown in FIG.
The pump P driven by the engine 12 supplies the oil from the tank T, which is substantially the vehicle body 1A, via the line filter F to the first control valve 6 of the loader 2 and the second control valve 8 of the backhoe 3 The liquid can be sent to the third control valve 11 of the hydraulic device 4.

The first control valve 6 and the second control valve 8 can be connected and separated by male and female couplers 12A and 12B, and the second control valve 8 and the third control valve 11 are connected by male and female couplers 13A and 13B. When the backhoe 3 is removed, the male and female couplers
The first control valve 6 and the third control valve 11 are connected in series by connecting 12A and 13B. In the circuit 14 on the return side of the first and second control valves 6, 8 and on the input side of the third control valve 11, a switching valve 15 is provided on the side wall of the hydraulic device 4 in this embodiment.

The switching valve 15 has an import port 17, an out port 18, and a drain port 19 in a valve block 16. A communication port 20 between the import port 17 and the drain port 19 is provided with a rotary pool 21. The valve block 16 is attached to the side wall of the hydraulic device 4 with bolts 22,
The rotary pool 21 has a hole 21 with the same area as the communication port 20.
A is formed in the radial direction, and when the spool 21 is rotated by operating the operation lever 23, the spool is fully opened (drain posture) shown in FIG. In FIG. 1A, reference numeral 25 denotes a relief valve of the same hydraulic system.

In the above embodiment, when the backhoe 3 is mounted and, for example, a groove excavation operation is performed, the three-point link does not need to be mounted. ) To fully open spool,
The male and female couplers 12A, 12B, 13A, 13B are connected respectively. In this state, the pressure oil from the pump P is sent to the second control valve 8 of the backhoe 3 via the first control valve 6, and the backhoe work is performed by operating the control valve 8, and the second control valve 8 In the return, the entire flow is returned to the tank from the drain port 19.

On the other hand, when the backhoe 3 is detached and the work of the impulse by the three-point link is performed, the male and female couplers 12A, 1
3B, the series circuit 14 is formed, and the rotary pool 21 is switched to the position having the diaphragm 24 as shown in FIG. In this state, the pressure oil from the pump P is sent to the third control valve 11 of the hydraulic device 4 via the import 17 and the out port 18 via the first control valve 6, and has a throttle 24 at this time. Therefore, a part of the total flow is released from the drain port 19 via the throttle 24, and an appropriate amount is sent to the third control valve 11. That is, in the present invention, the pressure oil from the pump P
And the first control valve 6 and the second control valve 8
2A, 12B and male and female couplers 13
A and 13B are connected to each other via the second control valve 8.
A first feed line for sending to a third control valve 11 and the second control valve
8 without passing through the male and female couplers 12A and 13B.
By connecting, the first control valve 6 and the third control valve 11 are connected.
To the second feed line to be sent to the third control valve 11
To the first and second feed lines.
A switching valve 15 in the inlet circuit 14 of the third control valve 11
The switching valve 15 is connected to the second feed line at the time of the first feed line.
Close the return oil from the control valve 8 to the third control valve 11
At the position of draining to tank T and the second feed line
A small amount of the total flow rate of the first control valve 6 is reduced
Drain to the tank T and send the remaining amount (appropriate amount) to the third control valve 11
It is configured to be able to switch to the position .

When the rotary pool 21 is fully closed as shown in FIG. 4 (B), the entire flow is sent to the three-point link. Can be for users who prefer the faster one. FIG. 5 shows a second embodiment of the present invention, and the first embodiment described above.
In the embodiment, the throttle 24 of the rotary pool 21 is formed by the amount of rotation, whereas in FIG.
24 are formed separately.

The second working device may be a box sprayer or the like other than the backhoe.

[0017]

The present invention is as described above. A part of the total flow is drained to a hydraulic device having a lift arm so that pressure loss and shock can be reduced without using an expensive priority valve or the like. Generation can be prevented.

[Brief description of the drawings]

1A is a configuration diagram of a hydraulic system, and FIG. 1B is a cross-sectional view of a switching valve.

FIG. 2 is a side view of the hydraulic device.

FIG. 3 is a rear view of the hydraulic device.

FIG. 4A is a cross-sectional view of the switching valve in a fully open state, and FIG.

FIG. 5 is a sectional view of a switching valve according to a second embodiment.

FIG. 6 is a side view of the tractor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Tractor 2 1st working device 3 2nd working device 4 Hydraulic device 6 1st control valve 8 2nd control valve 11 3rd control valve 15 switching valve 24 throttle

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁶ , DB name) B62D 41/00-63/08 A01B 63/10 E02F 9/22 F15B 11/00

Claims (1)

(57) [Claims] 1. A hydraulically operated first tractor (1) having a hydraulic device (4) having a lift arm (4A).
-It is equipped with two working devices (2) and (3), and supplies pressure oil from the pump (P) to the first control valve (6) and the first control valve (6) of the first working device (2) .
And the second control valve (8) of the second working device (3) and the hydraulic device
In the tractor hydraulic system for sending to the third control valve (11) in the position (4), the pressure oil from the pump (P) is supplied to the first control valve (6).
And the second control valve (8) by connecting the second control valve (8)
Via the first feed line to be sent to the third control valve (11) via
The first control valve (6) and the second control valve (8)
The third control valve (11) is connected and sent to the third control valve (11).
To be selected and sent to the second feed line.
The third control valve (1) in the first and second feed lines.
A switching valve (15) is provided in the inlet circuit (14) of 1),
The switching valve (15) performs the second control when the first feed line is used.
Return oil from valve (8) is closed to third control valve (11)
The position to drain to the stop tank (T) and the second feed line
, Throttle a small amount of the total flow of the first control valve (6)
Drain into tank (T) via (24) and regulate remaining amount to third
It is configured so that it can be switched to the position to send to the control valve (11).
Tractor hydraulic system, characterized by being.