JPH0244659Y2 - - Google Patents

Description

[Detailed description of the invention] (a) Industrial application field The present invention relates to a hydraulic system for controlling the ground pressure of a rice transplanter.

(b) Prior art A technique for reducing power loss by providing an on-off valve between the suction side and the discharge side of a pump and opening the on-off valve when the pump's discharge pressure is unnecessary is disclosed in Japanese Patent Application Laid-Open No. 51
The technique described in Japanese Patent No. 73700 is known.

(c) Problems to be solved by the invention Among agricultural machinery, walking type rice transplanters and riding rice transplanters use automatic ground pressure control to keep the ground pressure of the float constant.

This automatic control raises the hydraulic control valve and puts it in neutral.
By switching to ``lower'', the hydraulic cylinder expands and contracts, raising and lowering the wheels and raising and lowering the planting area to achieve the optimal ground pressure.However, during automatic control, ``neutral'' and ``lower'' ” and “raise”, the hydraulic control valve is always in a transitional switching state, and the spool of the hydraulic control valve continues to move while returning to the position between.

If the pressure oil is switched to the "raise", "lower", or "neutral" positions without fail, the pressure oil will flow into the hydraulic cylinder or return to the hydraulic oil tank as drain oil, allowing the relief valve to open. does not work, but during switching transitions such as between "neutral" and "up" and between "neutral" and "down", the hydraulic circuit becomes locked, and the connection between the hydraulic pump and the hydraulic control valve The relief valve is activated, pushing the relief valve,
The power consumption of the hydraulic pump increases to push out the pressure oil, resulting in a lack of engine horsepower.

In order to eliminate these drawbacks, the present invention provides a hydraulic system that can reduce power during unloading, has little circuit loss, can control flow rate by adjusting the opening of the on-off valve, and has a simple structure. It is something to do.

(d) Means for solving the problem The purpose of the present invention is as described above, and next, the configuration for achieving the purpose will be explained.

A planting section is attached to the rear of the traveling section via a hydraulic lifting device, the lower part of the planting section is supported by a float 10 that is grounded on the soil surface, and a ground pressure sensor is installed between the float 10 and the planting section. 5, and a hydraulic control valve 16 that feeds back the detection signal of the ground pressure sensor 5 via a wire, the hydraulic control valve 16
In a ground pressure control device that extends and retracts the hydraulic cylinder 4 of a hydraulic lifting device by operating "raise", "neutral", and "lower", the hydraulic control valve 16 is in the "neutral" position, and in the "raise" and "neutral" positions. The hydraulic pump 20 controls the opening/closing valve 18, which opens to prevent the hydraulic circuit from becoming locked when the hydraulic circuit is in the transition period between ``neutral'' and ``lower'' and the transition period between ``neutral'' and ``lower''. The opening/closing valve 18 is interposed between the suction side and the discharge side of the ground pressure sensor 5 and is configured to open and close in conjunction with the operation of the ground pressure sensor 5.

(E) Embodiment The purpose and structure of the present invention are as described above. Next, the structure of the embodiment shown in the attached drawings will be explained.

Fig. 1 is an overall side view of a riding rice transplanter, Fig. 2 is a hydraulic circuit diagram of the main parts of the present invention, and Fig. 3 is a drawing showing the relationship between the control position of the hydraulic control valve and the opening/closing position of the opening/closing valve.

FIG. 1 shows a state in which ground pressure control is performed in a riding rice transplanter.

The running parts of the riding rice transplanter are front wheels 13, 13 and rear wheels 1.
2 and 12 support the fuselage, 3 is a rear wheel drive case, 11 is an engine compartment, and 14 is a seat.

Engine and hydraulic pump 20 in engine room 11
is provided. A hydraulic control valve 16 is also provided within this. Reference numeral 17 is an operating lever for operating this hydraulic control valve 16, and a hydraulic cylinder 4 for moving the planting section up and down is also provided in the engine room 11.

A three-point link type work machine mounting device consisting of a top link 1 and lower links 2, 2 is provided between a running section and a planting section of a riding rice transplanter.

Of these, the top link 1 is connected to the hydraulic cylinder 4.
It is pushed up. In the planting section, a seedling platform 6 moves left and right on a seedling take-out plate, and a planting claw is driven by a planting drive case 8.

A ground pressure sensor 5 is provided between the float 10 and the planting drive case 8, and when the traveling part sinks due to unevenness of the tiller, the entire weight of the seedling stand 6, etc. is placed on the float 10, increasing the ground pressure. becomes large.

In such a case, the sensor 5 detects a change in the ground pressure, the signal is fed back through a wire, etc., the hydraulic control valve 16 is operated, and the hydraulic cylinder 4 lifts the planted area. 9 is a PTO connection shaft that transmits power.

FIG. 2 is a drawing of a hydraulic section showing an embodiment of the present invention. Pulley 15 is rotated by the engine,
Hydraulic pump 20 is rotated. Hydraulic oil is sucked from the hydraulic oil tank 24 through the oil supply path,
The pressure oil is discharged from the pressure oil passage 22 as pressure oil. The hydraulic pressure control valve 16 controls the direction of the hydraulic pressure to move the wheels up and down, or conversely to move the planting section up and down.

In the present invention, an on-off valve 18 is provided in the oil passage connecting the oil supply passage and the pressure oil passage. Open/close valve 1
8. The hydraulic control valve 16, the ground pressure sensor 5, and the hydraulic operating lever 17 are all connected by wires, links, etc., and when the hydraulic operating lever 17 is in the neutral position and in the transition period, the opening/closing valve is open, but when it is in the neutral position The opening/closing valve is configured to close when the transition period is left and the transition period is "up" or "down".

The relationship between "raise", "lower", "neutral", and "transition period" of the hydraulic control valve and the opening/closing of the on-off valve 18 is shown in FIG.

(f) Effects of the invention Since the invention is constructed as described above, it has the following effects.

The ground pressure control of the rice transplanter, which raises and lowers the planting area by detecting the ground pressure with the ground pressure sensor 5, is performed by continuously switching the spool of the hydraulic control valve 16 during the operation of the rice transplanter, and reciprocating near the transition period. Most of the time, control is performed with the spool of the hydraulic control valve 16 positioned near the switching transition period.

Therefore, the relief valve is open and pressurized oil is spouted out during the rice transplanting process, but by installing the on-off valve 18 as in the present invention, the relief valve can be kept open for a long period of time. This made it possible to avoid the problem of the heat generating state being maintained in the open state.

[Brief explanation of the drawing]

Fig. 1 is an overall side view of a riding rice transplanter, Fig. 2 is a drawing of the main parts of the present invention, and Fig. 3 is a drawing showing the relationship between the control position of the hydraulic control valve and the opening/closing position of the opening/closing valve. 16...Hydraulic control valve, 18...Opening/closing valve, 2
0...Hydraulic pump.

Claims (1)

[Scope of utility model registration request] A planting section is attached to the rear of the traveling section via a hydraulic lifting device, the lower part of the planting section is supported by a float 10 that is grounded on the soil surface, and a ground pressure sensor 5 is installed between the float 10 and the planting section. and a hydraulic control valve 16 that feeds back the detection signal of the ground pressure sensor 5 via a wire, and by operating the hydraulic control valve 16 to the "raise", "neutral", and "lower" positions, the hydraulic lifting device can be operated. In the ground pressure control device that expands and contracts the hydraulic cylinder 4 of
An on-off valve 18 is interposed between the suction side and the discharge side of the hydraulic pump 20, and opens the on-off valve 18 to prevent the hydraulic circuit from becoming locked when the hydraulic circuit is in the switching transition period. 18 is configured to open and close in conjunction with a ground pressure sensor 5.