JPH053759U - Hydraulic pilot operated valve - Google Patents

Abstract

(57) [Summary] [Purpose] To be able to provide three springs in a small spring case. A first-stage spring 24 is provided between a second retainer 27 in contact with a bottom wall 23a of a spring case 23 and a first retainer 25 in contact with a step portion 22a of a spool 22, and a first-stage spring 24 is in contact with a small diameter portion 22b of the spool 22. A second step spring 34 is provided between the third retainer 29 and the fourth retainer 33, and the fourth retainer 33 is brought into contact with the seat plate 32 attached to the small diameter portion 22b of the spool 22 with the collar 30 and the long bolt 31. , A third step spring 37 is provided between the seat plate 32 and the second retainer 27.
Is provided, and the second-stage springs 34 and 3 are provided on the inner peripheral side of the first-stage spring 24.
The step springs 37 can be arranged side by side in the axial direction.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 The present invention relates to a hydraulic pilot operated valve that supplies pressurized oil to a boom cylinder, a lift cylinder, etc. of a construction machine.

[0002]

[Prior Art]

 Various hydraulic pilot type operation valves are known. For example, the spool is slidably inserted into the left and right pressure oil supply positions with the neutral position as the boundary in the spool hole of the valve body, and the left and right springs installed in the left and right spring cases attached to the left and right sides of the valve body provide spooling. When the pilot pressure oil is supplied to the spring case in the left and right directions, the spool slides in the left and right directions to the pressure oil supply position, and the pilot pressure oil is inserted in the spring case in the left and right directions. It is known that when the oil is supplied, the spool slides in one direction to the left and right to reach the pressure oil supply position.

[0003]

[Problems to be solved by the device]

 The pressure reducing hydraulic pilot valve supplies pilot pressure oil into the left and right spring cases of the hydraulic pilot operating valve, and the output pressure of the hydraulic pilot valve increases in proportion to the operating stroke of the operating lever. The pressure characteristic is linear, and the spring characteristic of the spring in the spring case is linear.Therefore, multiple springs are combined in the spring case to make the spring characteristic non-linear, which causes a slight stroke of the spool. Fine controllability is improved by supplying a small amount of pressure oil to the actuator. In this way, the fine controllability can be improved by increasing the number of springs provided in the spring case, but since the size of the spring case is limited, only two bars have been provided in the past and the pilot has been limited. Fine pressure controllability was not sufficient because the pressure oil characteristics and spring characteristics did not completely match.

Therefore, an object of the present invention is to provide a hydraulic pilot type operation valve capable of solving the above-mentioned problems.

[0005]

[Means for Solving the Problems]

 In a spring case 23 having a spring for urging the spool 22, a first retainer 25 abutting on a step 22a of the spool 22, a second retainer 27 abutting on a bottom wall 23a of the spring case 23 and having a first stopper 26, The third retainer 29 having the second stopper 28 is brought into contact with the small-diameter end 22b of the spool 22, the collar 30 is attached to the small-diameter portion 22b of the spool 22, the seat plate 32 is provided with long bolts 31, and the seat plate 32 is brought into contact with the seat plate 32. A fourth retainer 33 having a third stopper 35 is provided, a first-step spring 24 is provided between the first and second retainers 25 and 27, and a second-step spring is provided between the third and fourth retainers 29 and 33. A hydraulic pilot operated valve provided with a spring 34 and a third stage spring 37 provided between the seat plate 32 and the second retainer 27.

[0006]

[Work]

 Since the second-stage spring 34 and the third-stage spring 37 can be arranged side by side in the axial direction on the inner peripheral side of the first-stage spring 24, three springs can be provided in the small spring case 23. Not only can the matching of oil pressure characteristics be improved to improve fine controllability, but also the spring case 23 can be made compact.

[0007]

【Example】

 As shown in FIG. 1, the hydraulic pilot operated valve 1 is provided between the hydraulic pump 2 and the cylinder 3, and an inlet port 4 connected to the discharge side of the hydraulic pump 2 is connected to a tank port 6 connected to a tank 5. The neutral position A that shuts off the first and second actuator ports 9 and 10 that communicate with each other, and that communicates with the raising chamber 7 and the lowering chamber 8 of the cylinder 3, and the communication between the inlet port 4 and the first actuator port 9 And a lowering position C where the second actuator port 10 communicates with the tank port 6 and a lowering position C where the inlet port 4 communicates with the second actuator port 10 and the first actuator port 9 communicates with the tank port 6. A floating position D communicating with the port is provided, and the hydraulic pilot valve 12 supplies the discharge oil of the pilot hydraulic pump 11 to the left and right pressure receiving portions 13, 14 as pilot pressure oil. In position B increased from the neutral position A, lowered position C, switching Erareru to the floating position D. As shown in FIG. 2, the spool 22 is slidably fitted in the spool hole 21 of the operation valve body 20, and the spool 22 projects into the spring cases 23 provided on the left and right end surfaces of the operation valve body 20, In the left spring case 23, a first retainer 25 that contacts the step portion 22a of the spool 22 and a second retainer 27 that contacts the bottom wall 23a of the spring case 23 and that has a cylindrical first stopper 26 are provided. The first-stage spring 24 is provided between the first retainer 25 and the second retainer 27, and the small diameter end 22b of the spool 22 is provided with a second cylindrical stopper 28. The third retainer 29 is in contact with the collar 30, and the collar 30 is attached through the long bolt 31 and the seat plate 32. The fourth retainer 33 in contact with the seat plate 32 and the third retainer 29 have two stages. Eye spring 34 is provided The first stopper 26 and the second stopper 28 face each other, and the distance L1 between them is the same as the stroke between the neutral position and the floating position of the spool 22, and the cylindrical shape provided on the fourth retainer 33 is provided. The third stopper 35 faces the fourth stopper 36 provided on the second retainer 27, and the distance L2 between them is the same as the stroke from the neutral position to the lowered position of the spool 22. A third step spring 37 is provided between the seat plate 32 and the seat plate 32.

Next, the operation will be described. The spool 22 is held in the neutral position by the first-stage spring 24 and the second-stage spring 34, and when pilot pressure oil is supplied to the inside of the left spring case 23, that is, the pressure receiving portion 13 on the left in FIG. When the eye spring 34 is compressed to the right and moved from the neutral position A to the raised position B, and the pilot pressure oil is supplied to the inside of the spring case 23 on the right side, that is, the pressure receiving portion 14 on the right side of FIG. When the third stopper 35 slides to the left against the third-stage springs 24 and 37, and the third stopper 35 comes into contact with the fourth stopper 36 of the second retainer 27, the neutral position A is lowered to the lowered position C, and the right pressure is received. When the pilot pressure oil is supplied to the portion 14, the spool 22 slides leftward while compressing the first-step spring 24 and the second-step spring 34, and the second stopper 28 comes into contact with the first stopper 26 so that the sp Lower 22 The floating position D from location C.

[0009]

[Effect of the device]

 The second-stage spring 34 and the third-stage spring 37 can be provided in parallel in the axial direction on the inner peripheral side of the first-stage spring 24, and three springs can be provided in the small spring case 23. Fine controllability can be improved by improving matching of pilot hydraulic characteristics.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view of a hydraulic pilot type operation valve.

FIG. 2 is a cross-sectional view of a hydraulic pilot type operation valve.

[Explanation of symbols]

12 hydraulic pilot valve, 13 one pressure receiving part, 14
The other pressure receiving portion, 22 spool, 23 spring case, 24
1st step spring, 25 1st retainer, 26 1st stopper, 27 2nd retainer, 28 2nd stopper, 29
3rd retainer, 30 collar, 31 long bolt, 32
Seat plate, 33 4th retainer, 342 step spring, 35 3rd stopper, 36 4th stopper, 37 3rd step spring.

Claims (1)

[Claims for utility model registration] 1. The spool 22 is held at the neutral position A by a spring force, and pilot pressure oil is supplied from the hydraulic pilot valve 12 to one of the pressure receiving portions 13 so that the spool 22 is at the neutral position. A hydraulic pilot type in which the spool 22 is moved from the neutral position A to one pressure oil supply position by moving from A to the other pressure oil supply position and supplying pilot pressure oil from the hydraulic pilot valve 12 to the other pressure receiving portion 14. In the operation valve, in a spring case 23 having a spring that biases the spool 22 to a neutral position, a first retainer 25 that abuts a step portion 22a of the spool 22, a bottom wall 23a of the spring case 23, and a first stopper. Second retainer 2 having 26
7, a third retainer 29 that comes into contact with the small-diameter end 22b of the spool 22 and has a second stopper 28, a collar 30 on the small-diameter portion 22b of the spool 22, a seat plate 32 provided with long bolts 31, and the seat plate 32. A fourth retainer 33, which is in contact with and has a third stopper 35, is provided, and the first and second retainers 2 are provided.
A first-stage spring 24 is provided between the fifth retainer 5 and the second retainer 27, a second-stage spring 34 is provided between the third and fourth retainers 29 and 33, and a third-stage spring 37 is provided between the second retainer 27 and the seat plate 32. A hydraulic pilot operated valve characterized by being provided with.