JP3635685B2 - Solenoid valve control device such as tractor - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a configuration of a solenoid valve control device such as a tractor . For example , a rotary plowing device mounted on a tractor, a harvesting device for a combine, a vehicle body tilting posture control device, and a rolling control for a seedling planting device. It can be used to use a solenoid valve.
[0002]
[Background Art and Problems to be Solved by the Invention]
The working part rolling solenoid valve such as a tractor is operated by switching the spool form, and the switching state continues for a while. At this time, since the high hydraulic pressure area and the non-pressure area that leads to the tank port, neutral port, etc. are provided adjacent to each other at the axial position of the spool valve, there will be a lot of leakage between the differential pressure areas and the contamination of the hydraulic pressure. When the degree is high, dust flows into each seal portion, resulting in a dust lock phenomenon, and the spool may not operate in the neutral position.
[0003]
[Means for Solving the Problems]
In view of the above problems, the present invention is a rolling cylinder (3) driven by pressure oil sent from a pump (P) to roll the work device (2) to the left and right with respect to the vehicle body, as in the invention of claim 1. And a rolling control solenoid valve (4) for switching an oil passage communicating with the cylinder (3) in order to drive the rolling cylinder (3) to extend or shorten, and an expansion / contraction length of the rolling cylinder (3) is detected. A stroke sensor (23) and a tilt sensor (19) provided on the vehicle body are provided, and the rolling cylinder (3) detects the left-right tilt angle of the vehicle body or the left-right tilt angle of the work device (2), and A tractor provided with a rolling control device for outputting energization to the solenoid valve (4) so as to maintain the horizontal horizontal posture or the horizontal tilt posture of the work device (2). Te,
In the rolling control device, the rolling control solenoid valve (4) can be switched by a manual switch operation so as to drive the rolling cylinder (3) to extend or shorten, and the manual switch operation allows the work device (2) to be switched. After the left / right inclination angle is operated to the maximum inclination angle, a dither frequency for vibrating the spool of the valve is output to the solenoid valve (4) .
[0004]
[Operation and effect of the invention]
In the invention of claim 1 configured as described above, in the operation by the automatic control, the rolling control solenoid valve 4 is moved in accordance with the inclination of the traveling ground so as to maintain the right and left inclined state or the horizontal state of the work device 2. An output is generated and the rolling cylinder 3 is driven to extend and contract.
On the other hand, when the solenoid valve 4 is switched by a manual switch operation and the rolling cylinder 3 is driven, a dither frequency for vibrating the spool of the valve 4 is output after the working device 2 stops at the maximum inclination angle.
[0005]
Thereby, for example, dust flowing into the seal portion or the like can be removed, and the dust lock phenomenon can be reduced. Moreover, such a rolling control solenoid valve 4 is vibrated by changing the energization output to the solenoid valve, so that the operation and configuration can be simplified.
[0006]
【Example】
1-7, the case where rolling control is performed by using the rotary tiller of the tractor as the work device 2 is illustrated. The vehicle body 1 has an engine mounted in a front bonnet 6, a clutch housing 7, a transmission case 8, and the like are provided in series, and a pair of left and right front wheels 10 that can be driven by a steering handle 9 are provided in the front portion. A rear wheel 11 is provided on the left and right sides of the rear portion of the case 8 with rear axle housings. Both the front and rear wheels 10 and 11 can be driven by a transmission mechanism in the transmission case 8. Reference numeral 12 denotes a hydraulic case on the transmission case 8, which has an oil pressure riff cylinder 13 and can lift and lower the lift arm 14. Reference numeral 15 is a fender, 16 is a cockpit, 17 is a controller, 18 is an operation lever, and 19 is a tilt sensor.
[0007]
On the rear side of the mission case 8, a rotary tilling device that rotationally transmits the tilling claws 22 is mounted as the work device 2 through a three-point link including a pair of left and right lower rings 20 and a top link 21. The pair of left and right lower links and the lift arm 14 are connected by a lift rod. The left and right lift rods are provided with a double-acting rolling cylinder 3 that can be expanded and contracted by hydraulic pressure. The lower link 20 on one side can be swung up and down with respect to the other to control the rolling of the work device 2, that is, the posture such as left and right inclination and horizontal. Reference numeral 23 denotes a feedback stroke sensor for detecting the expansion / contraction length of the rolling cylinder 3. Reference numeral 24 denotes a PTO shaft that interlocks with the tilling shaft of the tilling claw 22. Reference numeral 25 denotes a flat plate that covers the rear upper part of the tilling device.
[0008]
The hydraulic circuit 27 such as the single-acting lift cylinder 13, the double-acting rolling cylinder 3, and the auxiliary cylinder 26 has a hydraulic pump P 1 and a tank port T. The hydraulic circuit 27 includes the auxiliary cylinder 26. A sub-control valve 28 for expanding and contracting is provided to operate the work device 2 portion. Further, 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 through the flow dividing valve 29. The circuit on the lift cylinder 13 side includes an elevating control valve 32 having an electronically operated raising valve 30 and a lowering valve 31, a slow return valve 33, and the like.
[0009]
The circuit 5 of the rolling cylinder 3 includes a rolling solenoid valve 4 that electromagnetically switches from the neutral position to the expansion / contraction position, a pilot check valve 34, and the like. By the expansion and contraction of the rolling cylinder 3, the distance of the lower link 20 to the lift arm on the rolling cylinder 3 side is changed with respect to the lift rod of a certain length on either the left or right side. As a result, the working device 2 can be rolled with respect to the vehicle body 1, and the working device 2 can be maintained in a horizontal horizontal posture, or can be maintained at a constant left-right inclination angle.
[0010]
In addition to the hydraulic circuit 27 by the hydraulic pump P1, the hydraulic circuits 40 and 41 by the hydraulic pump P2 have a pressure reducing valve 42 and switch the orbit roll 43 that steers the front wheel 10 by the steering handle 9 and forward / reverse transmission. A reverser clutch actuator 44, an actuator 45 that engages and disengages the clutch of the PTO shaft, and the transmission of the front wheel 10 is switched from the neutral position to the rear wheel 11 at substantially the same speed or double speed to drive two wheels, constant speed four wheels, or double speed four A clutch actuator 46 or the like for selecting wheel drive is disposed, and a shift actuator 47 for shifting the traveling transmission is also disposed.
[0011]
The rolling solenoid valve 4 is provided as a direction switching valve in a spool valve state on the valve body 35 as shown in FIGS. 3 to 5, and the outputs of the solenoids A and B at both ends of the rolling solenoid valve 4 The spool valve is switched to the left and right. In 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.
[0012]
In the extended position (FIG. 4), the spool valve is pushed to the right side by the output of the solenoid A, and the pressure oil in the pump port P passes through the area of the pilot spool 36 to the extended port C of the rolling cylinder 3. Sent. In the contracted position (FIG. 5), on the contrary, the spool valve is pushed to the left by the output of the solenoid B, and the pressure oil in the pump port P is sent to the contracted port D of the rolling cylinder 3 through the pilot check valve 34. It is done.
[0013]
In the rolling control, the left / right inclination angle of the vehicle body 1 or the left / right inclination angle of the work device 2 is detected, whereby the rolling cylinder 3 is expanded / contracted by the output of the rolling solenoid valve 4, thereby Automatic control to maintain the tilted posture.
Such automatic rolling control is switched to manual, and the rolling solenoid valve 4 is output manually. Accordingly, when the inclination angle of the working device 2 to the left or right side with respect to the vehicle body 1 reaches the maximum, a dither frequency is applied to the solenoid A or B, and the spool valve is vibrated.
[0014]
When the rolling control is manually operated, the solenoid A or B is activated and the state continues for a while when the inclination amount of the working device 2 is maximum. At this time, the expansion port C or the contraction port D communicating with the pump port P is a high pressure portion by the main relief valve, and the T port and the neutral port N are zero on both sides of the high pressure portion. If it is high and there is a lot of leakage, dust tends to flow into each seal portion. However, the dust due to the dither frequency of the spool valve is removed to prevent dust lock around the spool.
[0015]
8 and 9, the difference from the above example is that a control valve 38 that is turned ON / OFF by a spring 37 and a solenoid E from a contraction port D of the rolling solenoid valve 4 to a port L below the rolling cylinder 3 in the vertical direction. Is not operated by normal rolling control, but when performing automatic rolling work with a rotary tiller or the like, this control valve 38 is operated (FIG. 9) to improve the followability of the rotary tiller (FIG. 9), 3. Sensitively follow the unevenness or horizontal surface of the soil surface, improve the leveling.
[0016]
10 and 11, the hydraulic circuit 40, 41 is different from the above example in that a power steering orbit roll 43 circuit is provided on the primary pressure side of the pressure reducing valve 42, and other various actuators 44 are arranged. The circuit 41 on the secondary side is provided as a secondary side, and a relief safety valve 48 for preventing the occurrence of abnormal pressure is provided in the circuit 41 on the secondary pressure side.
The circuit 40 on the primary pressure side of the pressure reducing valve 42 is higher than the set pressure on the secondary pressure side and rises to the maximum working pressure. When the secondary pressure rises to a constant pressure due to a failure of the pressure reducing valve 42 or the like, the safety valve 48 operates in the secondary pressure side circuit 41, so that no abnormal pressure is generated and the actuators 44 to 47 are prevented from being damaged.
[0017]
10 and 11, the valve body 49 of the pressure reducing valve 42 is provided with a poppet 50 pushed by a spring 51 on the side communicating from the pump port P to the primary pressure circuit 40, and the pilot needle against the pressure of the spring 51 is provided. The primary pressure is obtained by applying the pressure of the pilot chamber 39 from 52.
The pump port P communicates with the area 54 of the spool 53, and further communicates from the area 54 through the notch 55 to the area 56 of the secondary pressure circuit 41, and the secondary pressure on the secondary pressure circuit 41 side is obtained by opening the notch 55. The spool 53 is moved left and right by the oil pressure in the pilot chamber 57 at one end and the pressure by the spring 58 at the other end, and the secondary pressure is maintained at a constant pressure. The pilot chamber 57 communicates with the area 56 with a needle 59, and between the area 56 and a drain chamber T having a spring 58, a safety valve 48 made of a ball pushed by a spring 60 and a needle 61 are interposed. Let them communicate.
[0018]
When the spool 53 stops moving for some reason and the oil pressure on the pump port P side becomes high, the poppet 50 is opened to increase the pressure on the primary pressure circuit 40 side, and this pressure also increases the pressure on the secondary pressure circuit 41. It will be. At this time, the pressure in the area 56 prevents the abnormal increase in the pressure of the secondary pressure circuit 41 by the oil drained from the needle 61 through the safety valve 48 to the drain chamber T, and also prevents the abnormal increase in the primary pressure circuit 40. To do.
[Brief description of the drawings]
FIG. 1 is a hydraulic circuit diagram for hydraulically operating each part actuator.
FIG. 2 is a flowchart of rolling control.
FIG. 3 is a cross-sectional view of a rolling solenoid valve portion.
FIG. 4 is a cross-sectional view showing the operation.
FIG. 5 is a cross-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 a part of another embodiment.
FIG. 9 is a chart showing the operation.
FIG. 10 is a hydraulic circuit diagram showing a part of another embodiment.
FIG. 11 is a cross-sectional view of the pressure reducing valve portion.
[Explanation of symbols]
1 Car body 2 Working device 3 Rolling cylinder 4 Rolling solenoid valve 5 Rolling hydraulic circuit

Claims (1)

A rolling cylinder (3) driven by pressure oil sent from a pump (P) to roll the working device (2) left and right with respect to the vehicle body, and the cylinder (3) for extending or shortening the rolling cylinder (3) 3) A rolling control solenoid valve (4) for switching an oil passage communicating with 3), a stroke sensor (23) for detecting the expansion / contraction length of the rolling cylinder (3), and an inclination sensor (19) provided on the vehicle body. And the rolling cylinder (3) detects the left / right inclination angle of the vehicle body or the left / right inclination angle of the work device (2) to maintain the left / right horizontal posture or the left / right inclination posture of the work device (2). A tractor including a rolling control device for performing energization output to the solenoid valve (4),
In the rolling control device, the rolling control solenoid valve (4) can be switched by a manual switch operation so as to drive the rolling cylinder (3) to extend or shorten, and the manual switch operation allows the work device (2) to be switched. A solenoid valve control device for a tractor or the like , wherein a dither frequency for vibrating the spool of the valve is output to the solenoid valve (4) after the left / right tilt angle is operated to the maximum tilt angle .

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