JPS623338Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention includes a single-acting cylinder that operates a steering clutch, a second control valve that controls the supply of pressure fluid to the single-acting cylinder, and a downstream of the second control valve. a first control valve that is connected to the side flow path and receives pressure fluid only when the second control valve is in the neutral position;
A portion of the second return flow path connected to the tank port of the second control valve is connected to a first return flow path from the first control valve to the tank, so that the second control valve is neutralized. The present invention relates to a steering clutch operating structure configured to open the single-acting cylinder to a tank via the first return flow path at the first position.

This configuration is such that the single-acting cylinder is opened to the tank via the first return flow path when the second control valve is in the neutral position.
There is an advantage that the flow path and the valve can be simplified without providing separate return flow paths from the control valve to the tank and without increasing the number of valve ports.

On the other hand, if, for example, the single-acting steering cylinder and another fluid pressure actuator with a larger drive load are to be driven by one pump, the pressure required to operate the steering cylinder may be considerably greater than the pressure required to operate the steering cylinder. A pump with a discharge pressure of

In such a case, due to the high viscosity of the low-temperature working fluid at the time of engine startup, the pressure in the first return passage from the first control valve to the tank increases as the large-capacity pump operates, and the pressure increases. As a result, the pressure in the first return flow path may actuate the steering cylinder to the clutch disengaged side, making it impossible to drive, and the engine cannot run unless the viscosity decreases as the temperature of the working fluid increases. There was a problem that made it impossible.

In view of these circumstances, the present invention aims to solve the above-mentioned problems by adding a simple structure while maintaining the simplification of the valve and flow path configurations.

Embodiments of the present invention will be described in detail below with reference to the drawings.

A pre-processing section 5 consisting of a planted grain culm lifting device 2, a reaping device 3, and a reaped grain culm conveying device 4 is mounted on the front part of the machine body equipped with the crawler type traveling device ₁ , and is rotated up and down around the horizontal axis P1. The grain culm conveying device 4 is configured such that the cutting height can be _changed ;
By changing the stock delivery position with respect to the threshing feed chain 6, it is possible to change the length of the tip portion supplied to the threshing device 7, that is, to change the handling depth. The threshing device 9 is provided in the center of the machine for threshing by the cooperation of the feed chain 6 and the threshing section 7, and for transferring the threshed grains to the bagging section 8. A combine harvester is provided at the rear of the machine to shred the threshed waste straw to harvest and thresh the grain culms, and to shred the waste straw and discharge it from the rear of the machine.

Speed control for changing the traveling speed of the traveling device 1, direction control by selectively transmitting driving force to the left and right crawlers 1a, 1a of the traveling device 1, and
The cutting height control for raising and lowering the pre-processing section 5 and the handling depth control by the harvested grain culm conveying device 4 are configured to be performed by pressurized fluid supplied from one hydraulic pump 12, respectively.

Explain cutting height control.

A ground following sensor 22 which is rotatably biased downward around the horizontal axis _P3 is provided on the grass dividing rod 10, and a device is provided to detect the amount of sensor swing when this sensor 22 comes into contact with the ground. The detection results,
The signal is configured to be transmitted to the cutting height control electromagnetic valve 23. This cutting height control electromagnetic valve 23 includes ports for switching between a pressurized oil supply state and a dischargeable state to the single-acting cylinder 26, and supplies pressure oil from the pump 12 to a direction control valve (described later). There is also a center bypass port. The height of the pre-processing section 5 above the ground is maintained at a set height by driving the heavy pre-processing section 5 up and down by the extension and shortening of the single-acting hydraulic cylinder 26 and using its large weight. It is configured to perform automatic cutting height control as much as possible.

Explain direction control.

Sensors 1 are installed on the left and right branching rods 10, 10, which form paths for introducing grain culms to be harvested into the lifting device 1, respectively.
1 and 11 are rotatably biased so as to take a grain culm detection posture that enters the introduction path, and can be rotated to be retired by contact with the planted grain culm.

Then, the steering clutch 13 or 13 is actuated by the retiring rotation of the sensor 11 or 11, and the driving force is selectively transmitted to the left and right crawlers 1a, 1a, so that the aircraft is planted in a row. It is configured to automatically control the direction so as to follow the grain culm.

In actuating the steering clutches 13, 13,
Single acting cylinders 14, 14 which are elastically biased in the clutch engagement direction are connected to the respective clutches 13, 13,
Between these two cylinders 14, 14 and a constantly driven hydraulic pump 12 driven by the engine, there are ports 15, 16 for selectively switching the hydraulic pressure supply to both cylinders 14, 14, and both cylinders 14, 14 in a pressure oil release state, and a neutral port 17 forming a bypass path for further supplying pressure oil from the bypass port of the cutting height control valve 23 to a cutting depth control valve (described later). The sensors 11, 11 detect the lateral displacement of the machine body with respect to the planted grain culms arranged in rows.
An electromagnetic control valve 18 is provided which is configured to be activated in response to the detection result.

Explain depth control.

The pulling device 2 is provided with culm length detection sensors 24 in three stages, upper and lower, and these sensors 2
4... is configured to transmit the culm length detection result to the handling depth control electromagnetic valve 25. The handling depth control valve 25 is provided with ports for switching the direction of pressure oil supply to the double-acting cylinder 27 and a port for returning the pressure oil supplied from the direction control valve 18 to the tank. be. Further, by expanding and shortening the hydraulic cylinder 27, handling depth control is performed to cope with changes in culm length and maintain the handling depth at a set state.

The direction control cylinders 14, 14 when the electromagnetic valves 23, 18, 25 are in the neutral state, respectively.
A second return passage from said cylinders 14, 14 to a first return passage 19 from pump 12 to the tank.
The return flow path 20 is connected to simplify the flow path configuration.

In the second return flow path 20 when the valve 18 is in the neutral state, from the pump 12 to the cylinder 14,
Portion 20a not involved in supplying pressure fluid to 14
A check valve 21 is provided to prevent pressure fluid from being supplied to the cylinders 14, 14 from the first return passage 19 through the second return passage 20, so that the working fluid is kept at a low temperature when the engine is started. Due to the high viscosity state caused by the operation of the large capacity pump 12, the 119th and second return passages 20
Due to the extremely large increase in the internal pressure of the steering cylinders 14, 14, the steering clutches 13, 13
This prevents the vehicle from becoming unable to travel due to activation on the cut side.

As clarified in the above embodiments, the characteristic configuration of the present invention includes a single-acting cylinder that operates the steering clutch, a second control valve that controls the supply of pressure fluid to the single-acting cylinder, and a second control valve that controls the supply of pressure fluid to the single-acting cylinder. a first control valve that is connected to the flow path downstream of the second control valve and receives pressure fluid only when the second control valve is in a neutral position;
A portion of the second return flow path connected to the tank port of the second control valve is connected to a first return flow path from the first control valve to the tank, so that the second control valve is neutralized. In the steering clutch operation part structure configured to open the single-acting cylinder to the tank via the first return passage at a position, the steering clutch operating part structure is configured such that the single-acting cylinder is opened to the tank via the first return passage. This configuration includes a check valve that prevents pressure fluid from flowing back into the single-acting cylinder, and this configuration provides the following effects.

That is, by providing a check valve in the middle of the second return flow path, the steering clutch is prevented from increasing pressure inside the pipe due to the high viscosity state of the working fluid when starting the engine, etc. It is possible to reliably prevent the cylinder from operating toward the clutch disengaged side, and it is therefore possible to start driving immediately after starting the engine. Moreover, since this is a simple improvement in which a check valve is provided in an existing flow path, the original purpose of simplifying the control valve and piping configuration by merging the return flow paths of the cylinders is not impaired.

In this way, as a means to prevent the vehicle from being unable to run, it is possible to increase the stress of the spring that biases the steering clutch in the direction of engagement. Involves structural changes.

[Brief explanation of the drawing]

The drawings show an embodiment of the structure of the steering clutch operating section according to the present invention, and FIG. 1 is a side view of the entire combine harvester, and FIG. 2 is an explanatory diagram showing the hydraulic operating system. 13... Steering clutch, 14... Single acting cylinder, 18... Second control valve, 19, 20a...
...Return flow path, 21...Check valve, 25...First control valve.

Claims (1)

[Scope of utility model registration request] Single acting cylinder 14 operating steering clutch 13
and a second control valve 18 that controls the supply of pressure fluid to the single-acting cylinder 14; and a second control valve 18 that is connected to a flow path downstream of the second control valve 18, and the second control valve 18 is in a neutral position. The second control valve 18 is provided in the first return passage 19 from the first control valve 25 to the tank. The portion 20a of the second return flow path 20 connected to the tank port is connected to the single-acting cylinder 1 at the neutral position of the second control valve 18.
4 is opened to the tank via the first return flow path 19, in the steering clutch operating section structure, in the middle of the second return flow path portion 20a,
From the first return passage 19 to the single acting cylinder 14
A steering clutch operating section structure characterized by being provided with a check valve 21 for preventing backflow of pressure fluid to the steering clutch.