JP2577208Y2 - Hydraulic pilot operated valve - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic pilot operated valve for supplying hydraulic oil to a boom cylinder, a lift cylinder, etc. of a construction machine.

[0002]

2. Description of the Related Art Various types of hydraulic pilot operated valves are known. For example, the spool is slidably fitted into the left and right pressure oil supply positions with the neutral position as a boundary in the spool hole of the valve body, and the spool is neutralized by the left and right springs provided in the left and right spring cases attached to the left and right sides of the valve body. When the pilot pressure oil is supplied to the left and right one-way spring case, the spool slides in the other direction to the left and right to the pressure oil supply position. There is a known one that slides in one direction to become a pressure oil supply position.

[0003]

The pilot pressure oil is supplied from the pressure reducing hydraulic pilot valve into the left and right spring cases of the hydraulic pilot operating valve, and the output pressure of the hydraulic pilot valve is proportional to the operating stroke of the operating lever. Since the pressure characteristic becomes linear and the spring characteristic of the spring in the spring case is linear, a plurality of springs are combined in the spring case to make the spring characteristic non-linear, thereby making the spool minute. Fine controllability is improved by allowing a small amount of pressure oil to be supplied to the actuator by making a stroke. As described above, fine controllability can be improved by increasing the number of springs provided in the spring case. However, since the size of the spring case is limited, conventionally only two springs are provided and the pilot pressure oil Fine controllability was not sufficient because the characteristics and the spring characteristics did not perfectly match.

Therefore, an object of the present invention is to provide a hydraulic pilot type operation valve which can solve the above-mentioned problem.

[0005]

The spool 22 is biased in both left and right directions by left and right springs to hold the spool 22 at the neutral position A,
By supplying pilot pressure oil from the hydraulic pilot valve 12 to one of the left and right pressure receiving portions 13, the spool 22 is moved from the neutral position A to the other left and right raising position B against the other left and right springs. Left and right other pressure receiving part 14
In the hydraulic pilot type operation valve which moves the spool 22 from the neutral position A to one of the left and right lowering positions C and the floating position D by supplying the pilot pressure oil to the left and right springs, The step 22 of the spool 22 is placed in a spring case 23 having a spring that biases the other side.
a, a second retainer 27 that contacts the bottom wall 23a of the spring case 23 and has a first stopper 26 and a fourth stopper 36, and a second stopper that contacts the small-diameter end 22b of the spool 22. A third retainer 29 having a second stopper 28, a seat plate 32 provided on the small-diameter end portion 22b of the spool 22 via a long bolt 31 and a third stopper 35 movable along the collar 30 in the left-right direction. The first and second retainers 33 are provided.
A first-stage spring 24 is provided between the retainers 25 and 27 to urge the spool 22 to the other left and right, and the third and fourth retainers 2 are provided.
A fourth-stage spring 34 is provided between the second and third retainers 33 and 33.
Is biased to one of the left and right sides to abut against the seat plate 32, a third-stage spring 37 is provided between the seat plate 32 and the fourth stopper 36, and the first and second stoppers 2 are provided when the spool 22 is in the neutral position.
The distance _{L 1} between 6, 28 and the same as stroke up the floating position D from the neutral position A of the spool 22, the spool 22
Is in the neutral position A, the third stopper 35 and the fourth
L ₁ the distance L2 between the stopper 36 identical to the stroke up to the position C is lowered from the neutral position A of the spool 22>
Hydraulic pilot type control valves, characterized in that the L _2.

[0006]

[Operation] The second-stage spring 3 is provided on the inner peripheral side of the first-stage spring 24.
The fourth and third-stage springs 37 can be provided in parallel in the axial direction, and three springs can be provided in the small spring case 23. Therefore, matching between the spring characteristics and the pilot hydraulic characteristics is improved to improve fine controllability. it can.
When the pilot pressure oil is supplied to the other left and right pressure receiving portions 14, the spool 22 starts moving from the neutral position A to the left or right while compressing the left and right first-stage springs 24 and the third-stage springs 37, and moves to the lower position. C. When the spool 22 is at the lower position C, the third stopper 35 contacts the fourth stopper 36. When the spool 22 moves further to the left or right, the spool 22 moves from the lowered position C to the floating position D while compressing the second-stage spring 34 together with the first-stage spring 24 and the third-stage spring 37 on the left or right. Then, the first stopper 26 and the second stopper 28 come into contact with each other and are positioned at the floating position D. As described above, while the spool 22 is moved from the neutral position A to the lowered position C, the left and right first-stage springs 24 and the third-stage spring 37 are compressed, and are moved from the lowered position C to the floating position D. Left and right first-stage springs 24,
Since the second-stage spring 34 and the third-stage spring 37 are compressed, the spring force rapidly increases, and the pilot pressure oil must be rapidly increased to move the spool 22 from the lower position to the floating position. . Therefore, the hydraulic pilot valve 12
If the operating stroke is within a certain range, the spool 22 is held at the lowered position. Therefore, in the hydraulic pilot type operating valve having the floating position, even if there is a variation in the spring force or a variation in the output pressure of the hydraulic pilot valve, the spool 22 is moved. Can be moved to the lowered position accurately. Therefore, for example, when supplying pressurized oil to the lift cylinder, the flow rate of return oil from the lift cylinder to the tank can be set to a predetermined value, and the descending speed can be set to a predetermined speed.

[0007]

[Embodiment] As shown in FIG. 1, a hydraulic pilot type operation valve 1 is provided between a hydraulic pump 2 and a cylinder 3.
An inlet port 4 connected to the discharge side of the hydraulic pump 2 communicates with a tank port 6 which communicates with a tank 5, and a cylinder 3
A neutral position A for shutting off the first and second actuator ports 9 and 10 communicating with the raising chamber 7 and the lowering chamber 8, and the inlet port 4 and the first actuator port 9, and the second actuator port 10 and the tank. A lifting position B communicating the port 6, a lowering position C communicating the inlet port 4 with the second actuator port 10 and communicating the first actuator port 9 with the tank port 6, and a floating position D communicating the ports; The hydraulic pilot valve 12 supplies the oil discharged from the pilot hydraulic pump 11 as pilot pressure oil to the left and right pressure receiving units 13 and 14, thereby switching the neutral position A to the raising position B, the lowering position C, and the floating position D. As shown in FIG. 2, a spool 22 is slidably fitted in a spool hole 21 of the operation valve body 20, and this spool 22 projects into a spring case 23 provided on the left and right end surfaces of the operation valve body 20, and The first retainer 25 in contact with the step 22a of the spool 22 and the spring case 23
First stopper 26 which abuts against the bottom wall 23a of the
A first-stage spring 24 is provided between the first retainer 25 and the second retainer 27, and a second cylindrical retainer 27 is provided on the small-diameter end 22 b of the spool 22. A third retainer 29 having a stopper 28 is in contact with the collar 30 and a collar 30 is mounted via a long bolt 31 and a seat plate 32, and the fourth retainer 3 is in contact with the seat plate 32.
A second-stage spring 34 is provided between the third stopper 29 and the third retainer 29, the first stopper 26 and the second stopper 28 are opposed to each other, and the distance L1 between the two stops from the neutral position of the spool 22 to the floating position. The third stopper 35 provided on the fourth retainer 33 is opposed to the fourth stopper 36 provided on the second retainer 27, and the distance L2 between them is set at the neutral position of the spool 22. A third-stage spring 37 is provided between the fourth stopper 36 and the seat plate 32 in the same stroke as the stroke from the position to the lowered position.

Next, the operation will be described. The spool 22 is held at a neutral position by a first-stage spring 24 and a second-stage spring 34, and inside the left spring case 23, that is, the left pressure receiving portion 13 in FIG.
When the pilot pressure oil is supplied to the spool 22, the spool 22 is turned to the right while compressing the second-stage spring 34 to the raised position B from the neutral position A, and the inside of the right spring case 23, that is, FIG.
When the pilot pressure oil is supplied to the right pressure receiving portion 14, the spool 22 digs into the first-stage and third-stage springs 24 and 37 and slides to the left, and the third stopper 35 moves the fourth retainer 27 of the second retainer 27.
When it comes into contact with the stopper 36, the neutral position A is moved to the lower position C.
When the pilot pressure oil is further supplied to the right pressure receiving portion 14, the spool 22 slides to the left while compressing the first-stage spring 24 and the second-stage spring 34, and the second stopper 28
The spool 22 comes into contact with the stopper 26 to move from the lowered position C to the floating position D.

[0009]

[Effect of the Invention] The second-stage spring 3 is provided on the inner peripheral side of the first-stage spring 24.
The fourth and third-stage springs 37 can be provided in parallel in the axial direction, and three springs can be provided in the small spring case 23. Therefore, matching between the spring characteristics and the pilot hydraulic characteristics is improved to improve fine controllability. it can.

[Brief description of the drawings]

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

FIG. 2 is a 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 part, 22 spool, 23 spring case, 24
1st stage spring, 25 first retainer, 26 first stopper, 27 second retainer, 28 second stopper, 29
3rd retainer, 30 collars, 31 long bolts, 32
Seat plate, 33 4th retainer, 342nd stage spring, 35 3rd stopper, 36 4th stopper, 37 3rd stage spring.

Continuation of front page (58) Fields surveyed (Int.Cl. ⁶ , DB name) F16K 31/12 F15B 13/042

Claims (1)

(57) [Scope of request for utility model registration] 1. A spool 22 is moved left and right by left and right springs.
Hydraulic pilot
Pilot pressure oil is supplied from the valve 12 to one of the left and right pressure receiving sections 13.
The spool 22 against the other spring on the left and right.
From the standing position A to the left or right raising position B, the hydraulic pie
The pilot pressure is applied from the lot valve 12 to the other
By supplying oil, the spool 22 resists one of the left and right springs.
From the neutral position A to one of the left and right lowering positions C and the floating position D
Sequentially moved to the hydraulic pilot type control valves, bar having a spring for biasing the spool 22 to the other of the left and right
Abuts the step 22a of the spool 22 in the necessity 23;
The first retainer 25 and the bottom wall 23a of the spring case 23.
Contact the first stopper 26 and the fourth stopper 36
2nd retainer 27 having, small diameter end 22 of spool 22
b and a third retainer having a second stopper 28
29, a collar 30 on the small-diameter end 22b of the spool 22,
The seat plate 32 provided via the bolt 31 and the collar 30
Has a third stopper 35 that can move in the left-right direction along
A fourth retainer 33 is provided, and the first and second retainers 2 are provided.
The first stage spring 24 is provided between 5 and 27 and the spool 22 is moved to the left.
Energize to the other right side, between the third and fourth retainers 29 and 33
And the fourth retainer 33 in one of the left and right directions.
To abut against the seat plate 32, and the seat plate 32 and the fourth stopper
A third stage spring 37 is provided between the spool 22 and the spool 22.
Between the first and second stoppers 26 and 28 when in the neutral position.
The floating position D from the neutral position A of the distance _{L 1} spool 22 or
And the spool 22 is in the neutral position A
The third stopper 35 and the fourth stopper 3
6 from the neutral position A of the spool 22
_L identical to the stroke to bottom position C 1> _{L 2} Toshitako
And a hydraulic pilot operated valve.