JP2019060418A - Hydraulic pilot valve - Google Patents

Abstract

To provide a hydraulic pilot valve capable of steplessly and stably adjusting a secondary pressure characteristic.SOLUTION: A hydraulic pilot valve has: an insertion member 11 inserted into an open hole 2a penetrating a valve case 2, at a position on one end side in a stroke direction with respect to a spool 4, and opposite to the spool 4 in the stroke direction; and a spring 12 arranged between the insertion member 11 and the spool 4. A position of the insertion member 11 in the stroke direction of the spool 4 can be adjusted steplessly from the outside of the valve case 2.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a hydraulic pilot valve that strokes a spool in accordance with an amount of operation from the outside and changes a secondary pressure in accordance with the position of the spool in the stroke direction.

  Hydraulic pilot valves are used in hydraulic circuits in construction machines such as hydraulic shovels and hydraulic cranes. The hydraulic pilot valve strokes the spool provided in the valve case by lever operation, and changes the secondary pressure (pilot pressure) according to the lever operation amount. At this secondary pressure, an attachment such as a shovel provided on the construction machine is operated.

  In a hydraulic pilot valve, when the lever depresses the seat, a spring provided between the seat and the spool compresses to move the spool. At this time, the force F pressing the spool in accordance with the amount of operation of the lever balances the force f of the primary pressure which overflows from the opening of the spool, and the secondary pressure is determined.

  The secondary pressure characteristics with respect to the amount of lever operation are determined by the specifications of the spring. And, by changing the secondary pressure characteristic, it is possible to change the movement of the construction machine, that is, the operability of the construction machine. However, in order to change the secondary pressure characteristics, it is necessary to replace the spring, which takes time from disassembling the hydraulic pilot valve to reassembly.

  Therefore, Patent Document 1 discloses a pilot valve provided with resistance means for selectively applying a force in the direction of resisting the operation force F from the outside to the remote control spool. The piston provided in the resistance means presses the remote control spool by the secondary pressure of the pilot valve. Thereby, the secondary pressure characteristic of the pilot valve with respect to the operation amount X is switched.

  Further, Patent Document 2 discloses a hydraulic pilot valve in which a valve body that generates a pilot pressure by stroke operation of a spool and a proportional valve unit that opposes the spool of the valve body are incorporated in a valve case. . The plunger is stroked to the reaction force spring side by the pilot hydraulic pressure from the outside, the reaction force to the spool is strengthened, and the pilot pressure is reduced.

Japanese Patent Application Laid-Open No. 10-132107 JP 2003-329008 A

  However, in Patent Document 1, the secondary pressure characteristic to be changed is one pattern, which is determined by the piston diameter. Therefore, the secondary pressure characteristic can not be adjusted steplessly. Moreover, in patent document 2, when the pilot oil pressure from the outside leaks into the space which a plunger moves, the pressure in this space fluctuates, and there exists a problem that adjustment of a secondary pressure characteristic disperses.

  An object of the present invention is to provide a hydraulic pilot valve capable of steplessly and stably adjusting the secondary pressure characteristic.

  The present invention is a hydraulic pilot valve that strokes a spool provided in a valve case in accordance with the amount of operation from the outside, and changes the secondary pressure in accordance with the position of the spool in the stroke direction. Also, at a position on one end side of the stroke direction, it is inserted into a through hole that penetrates the valve case, and is disposed between an insertion member facing the spool in the stroke direction, the insertion member, and the spool A spring, and the position of the insertion member in the stroke direction can be adjusted steplessly from the outside of the valve case.

  According to the present invention, the spring is disposed between the insertion member and the spool. Therefore, when the spool moves toward the insertion member, the spool receives the biasing force of the spring. The position of the insertion member in the stroke direction of the spool can be adjusted steplessly from the outside of the valve case. Therefore, by adjusting the position of the insertion member, it is possible to intensify or weaken the biasing force from the spring received by the spool. Thereby, the secondary pressure characteristic can be adjusted steplessly. Further, since the biasing force of the spring is utilized, even if the pressure leaks into the space where the spring is disposed, the pressure is not affected and the adjustment of the secondary pressure characteristic does not vary. Thereby, the secondary pressure characteristic can be stably adjusted.

It is sectional drawing of the hydraulic pressure pilot valve in 1st Embodiment. It is a figure which shows the relationship of the operation amount from the outside, and secondary pressure in 1st Embodiment. It is sectional drawing of the hydraulic pressure pilot valve in 2nd Embodiment. It is a figure which shows the relationship of the operation amount from the outside, and secondary pressure in 2nd Embodiment.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

First Embodiment
(Configuration of hydraulic pilot valve)
The hydraulic pilot valve of the first embodiment is provided in a construction machine such as a shovel. The hydraulic pilot valve strokes the spool in accordance with the amount of operation from the outside, and changes the secondary pressure (pilot pressure) in accordance with the position of the spool in the stroke direction. The operation of an attachment or the like provided to the construction machine is controlled by switching and operating the control valve (not shown) by the secondary pressure.

  The hydraulic pilot valve 1 has a valve case 2, a spring seat 3, and a spool 4 as shown in FIG. 1 which is a cross sectional view.

  A lever attachment portion 5 is attached to an upper portion in the center of the valve case 2 so as to be rotatable in the lateral direction in the drawing. A lever (not shown) is attached to the lever attachment portion 5. A cam plate 6 is fixed around the lever mounting portion 5.

  The spring seat 3 is disk-shaped and disposed inside the valve case 2. The spool 4 is inserted through the center of the spring seat 3. A push rod 7 is disposed above the spring seat 3 in the figure. When the lever is turned, the push rod 7 is pushed downward in the figure by the cam plate 6 by a height corresponding to the amount of operation. When the push rod 7 is pushed down, the spring seat 3 is pushed down by the push rod 7 and moves downward in the figure from the illustrated home position.

  The spool 4 is provided inside the valve case 2 and disposed in the vertical direction in the drawing. The upper portion 4 a of the spool 4 is larger in diameter than a portion through which the spring seat 3 is inserted, and is in contact with the spring seat 3 from above.

  A spring 8 is provided between the spool 4 and the spring seat 3. When the spring seat 3 moves downward, the spool 4 is pushed by the spring 8 and moves downward in FIG.

  When the spool 4 moves downward, a part of the primary pressure supplied from the lower input port 10 of the valve case 2 is output as the secondary pressure from an output port (not shown). The secondary pressure changes according to the position of the spool 4.

  A spring 9 is provided between the valve case 2 and the spring seat 3. When the lever is not operated, the spring seat 3 which has been moved downward is pushed up by the biasing force of the spring 9 and returns to the home position. At this time, the upper portion 4a of the spool 4 is pushed up by the spring seat 3, whereby the spool 4 returns to the home position. Thus, the spool 4 is stroked according to the amount of operation from the outside.

(Insertion member)
Further, the hydraulic pilot valve 1 has an insertion member 11. The insertion member 11 is inserted through the through hole 2 a passing through the valve case 2 at a position closer to the lower end (one end) in the stroke direction than the spool 4 and is opposed to the spool 4 in the stroke direction.

  The insertion member 11 is coupled to the through hole 2 a by a screw. That is, the screw is cut on the outer periphery of the insertion member 11, and the inner periphery of the through hole 2a is also screwed. Therefore, by turning the screw, it is possible to adjust the position of the insertion member 11 in the stroke direction of the spool 4 steplessly.

  At the upper end of the insertion member 11 in the drawing, a protrusion 11 a that protrudes toward the spool 4 is provided.

  The hydraulic pilot valve 1 also has a spring 12 disposed between the insertion member 11 and the spool 4. The upper end of the spring 12 is in contact with the spool 4 in a non-compressed state. Further, the lower end of the spring 12 is fixed to the insertion member 11 by fitting the lower end thereof to the projection 11 a.

  In such a configuration, when the spool 4 moves toward the insertion member 11, the spool 4 receives the biasing force of the spring 12. Then, by adjusting the position of the insertion member 11 in the stroke direction of the spool 4, it is possible to intensify or weaken the biasing force from the spring 12 that the spool 4 receives. Thereby, the secondary pressure characteristic can be adjusted steplessly. Further, since the biasing force of the spring 12 is used, even if the pressure leaks into the space where the spring 12 is disposed, the pressure is not affected and the adjustment of the secondary pressure characteristic does not vary. Thereby, the secondary pressure characteristic can be stably adjusted.

  The relationship between the operation amount from the outside and the secondary pressure is shown in FIG. When the spring 12 is not provided, as indicated by the line A, the secondary pressure is generated when the operation amount reaches a predetermined amount, and linearly increases as the operation amount increases. On the other hand, when the spring 12 is provided, since the spool 4 receives the biasing force of the spring 12, the secondary pressure is lower than the value on the A line even with the same operation amount. Then, the closer the position of the insertion member 11 to the spool 4, the lower the secondary pressure for the same amount of operation. When the position of the insertion member 11 is closest to the spool 4, the operation amount and the secondary pressure have a relationship of line B in the figure. By adjusting the position of the insertion member 11, the secondary pressure characteristics can be arbitrarily adjusted between the A line and the B line in the region from the start to the end of the operation amount from the outside.

(effect)
As described above, according to the hydraulic pilot valve 1 according to the present embodiment, the spring 12 is disposed between the insertion member 11 and the spool 4. Therefore, when the spool 4 moves toward the insertion member 11, the spool 4 receives the biasing force of the spring 12. The position of the insertion member 11 in the stroke direction of the spool 4 can be adjusted steplessly from the outside of the valve case 2. Therefore, by adjusting the position of the insertion member 11, it is possible to intensify or weaken the biasing force from the spring 12 that the spool 4 receives. Thereby, the secondary pressure characteristic can be adjusted steplessly. Further, since the biasing force of the spring 12 is used, even if the pressure leaks into the space where the spring 12 is disposed, the pressure is not affected and the adjustment of the secondary pressure characteristic does not vary. Thereby, the secondary pressure characteristic can be stably adjusted.

  Further, the insertion member 11 is coupled to the through hole 2a by a screw. Therefore, the position in the stroke direction of the insertion member 11 can be adjusted steplessly easily by turning the screw. Further, the structure for steplessly adjusting the position in the stroke direction of the insertion member 11 can be simplified.

Second Embodiment
Next, a hydraulic pilot valve according to a second embodiment will be described with reference to the drawings. The description of the configuration common to the first embodiment and the effects exerted thereby will be omitted, and mainly the points different from the first embodiment will be described. In addition, about the same member as 1st Embodiment, the same code | symbol as 1st Embodiment is attached | subjected.

(Configuration of hydraulic pilot valve)
In the hydraulic pilot valve 101 of the present embodiment, as shown in FIG. 3 which is a cross sectional view, the lower end of the spring 112 disposed between the insertion member 11 and the spool 4 is the insertion member 11 in a non-compressed state. And the upper end is not in contact with the spool 4. The spring 112 may have a configuration in which the upper end is fixed to the spool 4 and the lower end is not in contact with the insertion member 11 in a non-compressed state.

  Since the upper end of the spring 112 is not in contact with the spool 4 in a state where the spring 112 is not compressed, the spool 4 does not receive a biasing force from the spring 112 until the spool 4 abuts on the upper end of the spring 112 . Therefore, the secondary pressure characteristic does not change until the spool 4 contacts the spring 112. On the other hand, when the spool 4 comes into contact with the spring 112 and the spring 112 is compressed, the secondary pressure characteristic changes due to the biasing force of the spring 112. As a result, the secondary pressure characteristic can be adjusted in the region from the intermediate region to the end of the operation amount from the outside.

  The relationship between the operation amount from the outside and the secondary pressure is shown in FIG. When the spring 112 is not provided, the operation amount and the secondary pressure have a relationship of line A in the figure. On the other hand, when the spring 112 is provided, the spool 4 does not receive the biasing force from the spring 112 in the region from the start end of the operation amount from the outside to the intermediate region where the spool 4 abuts the spring 112. Does not change. Since the spool 4 receives the biasing force from the spring 112 in the region from the intermediate region to the end of the operation amount from the outside, the secondary pressure is lower than the value on the A line even with the same operation amount. When the position of the insertion member 11 is closest to the spool 4, the operation amount and the secondary pressure have a relationship of a C line in the drawing. By adjusting the position of the insertion member 11, it is possible to arbitrarily adjust the secondary pressure characteristics between the A line and the C line in the region from the intermediate region to the end of the operation amount from the outside.

(effect)
As described above, according to the hydraulic pilot valve 101 according to the present embodiment, the spring 112 is fixed to the insertion member 11 in a non-compressed state and does not contact the spool 4. Therefore, the secondary pressure characteristics do not change with respect to the case where the spring 112 is not provided until the spool 4 contacts the spring 112. When the spool 4 comes into contact with the spring 112 and the spring 112 is compressed, the biasing force of the spring 112 changes the secondary pressure characteristics with respect to the case where the spring 112 is not provided. As a result, the secondary pressure characteristic can be adjusted in the region from the intermediate region to the end of the operation amount from the outside.

  As mentioned above, although embodiment of this invention was described, only the specific example was illustrated and it does not specifically limit this invention, and a design change can be suitably carried out for a specific structure. Further, the actions and effects described in the embodiments of the invention merely list the most preferable actions and effects resulting from the present invention, and the actions and effects according to the present invention are described in the embodiments of the present invention. It is not limited to what was done.

  For example, the insertion member 11 is not limited to a configuration in which the insertion member 11 is coupled to the through hole 2a by a screw. For example, the insertion member 11 may be a rod inserted into the through hole 2a, and a fixing member capable of fixing the movement of the rod in the stroke direction may be attached to the valve case 2. Even with such a configuration, the position of the insertion member 11 in the stroke direction can be continuously adjusted from the outside of the valve case 2 and the position of the insertion member 11 can be fixed. The insertion member 11 may be a telescopic rod or the like which can adjust its length steplessly and can fix its length.

1, 101 hydraulic pilot valve 2 valve case 2a through hole 3 spring seat 4 spool 5 lever mounting portion 6 cam plate 7 push rod 8 spring 9 spring 10 input port 11 insertion member 12, 112 spring

Claims (3)

A hydraulic pilot valve that causes a spool provided in a valve case to make a stroke in accordance with the amount of operation from the outside, and changes the secondary pressure in accordance with the position of the spool in the stroke direction,
An insertion member that is inserted into a through hole that penetrates the valve case at a position on one end side in the stroke direction with respect to the spool, and an insertion member that faces the spool in the stroke direction;
A spring disposed between the insertion member and the spool;
Have
A hydraulic pilot valve, wherein the position of the insertion member in the stroke direction can be adjusted steplessly from the outside of the valve case.   The hydraulic pilot valve according to claim 1, wherein the insertion member is screwed to the through hole.   The hydraulic pilot valve according to claim 1 or 2, wherein the spring is fixed to one of the insertion member and the spool in a non-compressed state and is not in contact with the other.

Images