JPH0856410A - Rolling solenoid valve of working part of tractor or the like - Google Patents

Abstract

PURPOSE: To prevent a space part between a spool valve and a valve body from clogging caused by making dust flow into the space part and keep smooth operation of the spool valve in a rolling solenoid valve for carrying out rolling control of a working part of tractor, combine, etc. CONSTITUTION: Dither frequency is imparted to a rolling solenoid valve 4 by changing over a rolling solenoid valve of hydraulic circuit for carrying out automatic rolling control by manual operation and maximizing left and right tilting angles of an operating apparatus to a vehicle body.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a working part rolling solenoid valve for a tractor, etc., and relates to a rotary tiller mounted on a tractor, a combine harvester, a vehicle body inclination control device, and a seedling planter. It can be used as a rolling solenoid valve for devices.

[0002]

2. Description of the Related Art A working part rolling solenoid valve such as a tractor is operated by switching spool types, and the switching state continues for a while. At this time, in the axial position of the spool valve, the high hydraulic pressure area and the non-pressure area communicating with the tank port, neutral port, etc. are provided adjacent to each other. If the degree is high, dust may flow into each seal portion, resulting in a dust lock phenomenon, and the spool may not operate in the neutral position.

[0003]

The present invention relates to a double-acting rolling cylinder 3 for rolling a working device 2 left and right with respect to a vehicle body 1, and a rolling solenoid valve 4 for controlling expansion and contraction of the rolling cylinder 3 by hydraulic pressure. In the rolling hydraulic circuit 5 having the above, the rolling solenoid valve 4 is manually switched to maximize the horizontal inclination angle of the work device 2 with respect to the vehicle body 1, thereby giving a dither frequency to the rolling solenoid valve 4. A rolling solenoid valve for a working unit such as a tractor.

[0004]

The left and right rolling action of the working device 2 with respect to the vehicle body 1 is performed by the rolling solenoid valve 4 of the rolling hydraulic circuit 5 being output in accordance with the inclination of the traveling ground to expand and contract the rolling cylinder 3. The left and right inclinations of the device 2 are controlled so as to be corrected and maintained horizontally.

Such a rolling solenoid valve 4
Is switched to the manual operation, and the work device 2 with respect to the vehicle body 1 is continued so as to maximize the horizontal inclination angle. This working device 2
The rolling cylinder 3 is expanded and contracted by switching the rolling solenoid valve 4, and the maximum tilt angle is obtained.
As a result, the rolling solenoid valve 4 is given a dither frequency and vibrates. This can reduce the dust lock phenomenon due to contaminants in the pressure oil. Moreover, since such a rolling solenoid valve 4 is vibrated by applying a dither frequency, its operation and structure can be simplified.

[0006]

1 to 7, a case where a rotary control device for a tractor is used as a working device 2 to perform rolling control is illustrated. The vehicle body 1 has an engine mounted in a front hood 6, a clutch housing 7, a transmission case 8 and the like are connected in series, and a pair of left and right front wheels 10 which can be driven by a steering handle 9 are provided in the front portion of the transmission. Rear wheels 11 are provided on the left and right sides of the case 8 by means of rear axle housings, and these front and rear wheels 10, 1
Both can be driven by a transmission mechanism in the mission case 8. Reference numeral 12 denotes a hydraulic case on the mission case 8, which has a hydraulic riff cylinder 13 therein and can lift and rotate the lift arm 14. Reference numeral 15 is a fender, 16 is a cockpit, 17 is a controller, 18 is an operating lever, and 19 is an inclination sensor.

On the rear side of the mission case 8, a rotary tiller for rotating and transmitting a tiller claw 22 through a three-point link consisting of a pair of left and right lower rings 20 and a top link 21 is mounted as a working device 2. The pair of left and right lower links and the lift arm 14 are connected by a lift rod,
A double-acting rolling cylinder 3 that is expanded and contracted by hydraulic pressure is provided on one of the left and right lift rods, and the expansion and contraction of the rolling cylinder 3 causes the lower link 20 on one of the left and right sides to swing up and down with respect to the other, thereby providing the working device 2 It is possible to control the rolling control, that is, the postures such as the right and left inclination and the horizontal. Reference numeral 23 denotes a feedback stroke sensor for detecting the length of expansion and contraction by the rolling cylinder 3. Reference numeral 24 denotes a PTO shaft, which interlocks with the tilling shaft of the tilling claw 22. Reference numeral 25 is a flat plate that covers the upper rear portion of the tiller.

The hydraulic circuit 27 including the single-acting lift cylinder 13, the double-acting rolling cylinder 3 and the auxiliary cylinder 26 has a hydraulic pump P1 and a tank port T. A sub-control valve 28 for expanding and contracting the auxiliary cylinder 26 is provided to operate the part of the working device 2. In the middle of the hydraulic circuit 27, the flow is divided into a circuit on the lift cylinder 13 side and a circuit on the rolling cylinder 3 side via a flow dividing valve 29. In the circuit on the side of the lift cylinder 13, a lift control valve 3 having an electronically operated raising valve 30 and a lowering valve 31 is provided.
2, a slow return valve 33, and the like.

In addition, the circuit 5 of the rolling cylinder 3 includes:
A rolling solenoid valve 4 that electromagnetically switches from a neutral position to a telescopic position, and a pilot check valve 34
And so on. The expansion and contraction of the rolling cylinder 3 changes the distance between the lower link 20 and the lift arm on the rolling cylinder 3 side with respect to the lift rod having a constant length on either the left or right side. This makes the car body 1
On the other hand, by rolling the working device 2, the working device 2 can be maintained in a horizontal posture in the left-right direction or can be maintained in a constant inclination angle in the left-right direction.

In addition to the hydraulic circuit 27 by the hydraulic pump P1, the hydraulic circuits 40, 41 by the hydraulic pump P2 have pressure reducing valves 42, and the orbit roll 43 for steering the front wheels 10 by the steering wheel 9 and the forward and backward movement. Reverser clutch actuator 44, PT for switching transmission
A clutch for selecting the two-wheel drive, constant-speed four-wheel drive, or double-speed four-wheel drive by switching the transmission of the actuator 45 for turning the O-axis clutch on and off, and the transmission of the front wheel 10 from the neutral position to almost the same speed or double speed as the rear wheel 11. An actuator 46 and the like are arranged, and further, a speed change actuator 47 that changes the speed of travel transmission is arranged.

Incidentally, the rolling solenoid valve 4
3 to 5, the valve body 35 is provided as a direction switching valve in a spool valve state, and the spool valve is switched left and right by the outputs of the solenoids A and B at both ends of the rolling solenoid valve 4. To be done. At the neutral position (FIG. 3), the left and right solenoids A and B are OFF, the hydraulic pressure supplied from the pump port P is sent to the neutral port N, and the rolling cylinder 3 is fixed at a fixed position.

At the extended position (FIG. 4), the solenoid A is
Is output to push the spool valve to the right, and the pressure oil in the pump port P is sent to the extension port C of the rolling cylinder 3 through the area of the pilot spool 36. At the retracted position (Fig. 5), on the contrary, the solenoid B
The spool valve is pushed to the left by the output of the pilot check valve 34
And is sent to the contraction port D of the rolling cylinder 3.

The rolling control is performed by adjusting the left and right inclination angles of the vehicle body 1,
Alternatively, the horizontal tilt angle of the working device 2 is detected, and thereby the rolling cylinder 3 is expanded and contracted by the output of the rolling solenoid valve 4, and the working device 2 is automatically controlled so as to maintain the horizontal horizontal position or the horizontal tilt position. Such automatic rolling control is switched to manual, and the rolling solenoid valve 4 is output manually. As a result, when the inclination angle of the work device 2 to the left or right reaches the maximum with respect to the vehicle body 1, the dither frequency is given to the solenoid A or B, and the spool valve is vibrated.

When manually operating the rolling control,
When the inclination amount of the work device 2 is maximum, the solenoid A or B is operated and this state continues for a while. At this time, the expansion port C or the contraction port D communicating with the pump port P is a high pressure part due to the main relief valve, and the pressures of the T port and the neutral port N become zero on both sides of this high pressure part, so that the differential pressure If there is a large amount and there is a large amount of leakage, dust tends to flow into each seal portion, but the vibration due to the dither frequency of the spool valve removes dust adhering to the spool and prevents dust lock.

8 and 9, the difference from the above example is that
From the contraction port D of the rolling solenoid valve 4 to the port L below the rolling cylinder 3 in the vertical direction,
An ON / OFF control valve 38 is provided by the spring 37 and the solenoid E so that it does not operate under normal rolling control, but when automatic rolling work is performed by a rotary tiller or the like, this control is performed to enhance the followability of the rotary tiller. The valve 38 is operated (FIG. 9) to sensitively follow the unevenness or the horizontal surface of the soil surface of the rolling cylinder 3 to improve the leveling property.

10 and 11, the difference from the above example is that in the hydraulic circuits 40 and 41, a circuit of a power steering orbit roll 43 is provided on the primary pressure side of the pressure reducing valve 42, and other various actuators 44 and the like are provided. The circuit 41 on the side to be arranged is the secondary side, and the relief safety valve 48 for preventing the abnormal pressure from being generated is provided in the circuit 41 on the secondary pressure side. Pressure reducing valve 4
The circuit 40 on the primary pressure side of 2 is higher than the set pressure on the secondary pressure side and rises to the maximum working pressure. Due to a failure of the pressure reducing valve 42,
When the secondary pressure rises to a constant pressure, this secondary pressure side circuit 41
Since the safety valve 48 operates, the abnormal pressure does not rise and the actuators 44 to 47 are prevented from being damaged.

In FIGS. 10 and 11, the pressure reducing valve 42
The valve body 49 of the poppet 50 is pushed by the spring 51 on the side communicating with the primary pressure circuit 40 from the pump port P.
Is provided, and the pressure of the pilot chamber 52 from the pilot needle 52 acts on the pressure of the spring 51 to obtain the primary pressure. The pump port P communicates with the area 54 of the spool 53, and further from this area 54 through the notch 55 to the area 56 of the secondary pressure circuit 41, and by opening the notch 55, the secondary pressure on the secondary pressure circuit 41 side is obtained. The spool 53 is moved left and right by the hydraulic pressure in the pilot chamber 57 at one end and the pressure by the spring 58 at the other end, so that the secondary pressure is maintained at a constant pressure. The pilot chamber 57 communicates with the area 56 by a needle 59, and a spring 6 is provided between the area 56 and a drain chamber T having a spring 58.
Safety valve 48 consisting of a ball pushed by 0 and needle 6
1 and communicate with each other.

When the spool 53 does not move for some reason and the hydraulic pressure on the pump port P side increases, the poppet 50 is opened to increase the pressure on the primary pressure circuit 40 side, and this pressure is the pressure on the secondary pressure circuit 41. Will also be higher. At this time, the pressure in the area 56 is from the needle 61,
The drainage of oil flowing through the safety valve 48 into the drain chamber T prevents the pressure in the secondary pressure circuit 41 from rising abnormally, and also prevents the pressure in the primary pressure circuit 40 from rising abnormally.

[Brief description of drawings]

FIG. 1 is a hydraulic circuit diagram for hydraulically operating each actuator.

FIG. 2 is a flowchart of rolling control.

FIG. 3 is a sectional view of a rolling solenoid valve portion.

FIG. 4 is a sectional view showing the operation.

FIG. 5 is a sectional view showing the operation.

FIG. 6 is a side view of the tractor.

FIG. 7 is a rear view thereof.

FIG. 8 is a hydraulic circuit diagram showing another embodiment.

FIG. 9 is a chart showing the operation.

FIG. 10 is a hydraulic circuit diagram showing another embodiment.

FIG. 11 is a sectional view of the pressure reducing valve section.

[Explanation of symbols]

 1 vehicle body 2 working device 3 rolling cylinder 4 rolling solenoid valve 5 rolling hydraulic circuit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shiro Katsuno No.1 Hachikura, Tobe Town, Iyo-gun, Ehime Prefecture

Claims (1)

[Claims] 1. A rolling hydraulic circuit 5 having a double-acting rolling cylinder 3 for rolling a working device 2 left and right with respect to a vehicle body 1, and a rolling solenoid valve 4 for controlling expansion and contraction of the rolling cylinder 3 by hydraulic pressure.
In order to maximize the horizontal tilt angle of the working device 2 with respect to the vehicle body 1 by manually switching the rolling solenoid valve 4, a working unit such as a tractor characterized by giving the rolling solenoid valve 4 a dither frequency. Rolling solenoid valve.