JPH0727107A - Servo valve - Google Patents

Abstract

PURPOSE:To remove the foreign matters entering the tip part of a flapper nozzle while an adequate operation is ensured. CONSTITUTION:A slide nozzle 14 having a passage 18 in its center part is slidably provided in a nozzle body 43. A spring 16 for energizing the slide nozzle 14 toward the tip part is provided in a space 15 between the slide nozzle 14 and the nozzle body 13. Passages 20 are formed between the outer peripheral surfaces close to the tip part and the rear end part of the slide nozzle 14 and the inner peripheral surface of the nozzle body 13 so as to allow the passages 20 to function as dampers for damping the sliding speed of the slide nozzle 14. The gap DELTAZ between the tip part of the nozzle body 13 and a flapper 6 is made larger than the gap DELTAx between the tip part of the slide nozzle 14 and the flapper 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a servo valve used for a servo mechanism or the like.

[0002]

2. Description of the Related Art Conventionally, servo valves have been widely used in servo mechanisms and the like. Here, a servo mechanism using this servo valve will be described by taking the one shown in FIG. 4 as an example.
When an external force F acts on the lever 2 of the servo mechanism 1, the lever 2 is swung about the fulcrum 3 and the servo valve 4
The distance Δx between the flapper nozzle 5 and the flapper 6 provided at the end of the lever 2 is narrowed. And this interval Δ
By narrowing x, the pressure in the space 7 inside the flapper nozzle 5 increases and a difference in pressure with the space 8 occurs.
As a result, the piston 9 moves in the direction of arrow A in FIG.
The distance Δx between the flapper 6 and the tip of the flapper nozzle 5 is returned to the predetermined distance.

[0003]

By the way, in the servo mechanism 1 using the servo valve 4 including the flapper nozzle 5 and the flapper 6 as described above, for example, foreign matter is contained in the fluid supplied to the flapper nozzle 5. When the foreign matter is mixed in, the foreign matter is caught by the tip of the flapper nozzle 5 and the flapper 6.
There is a risk that the lever 2 may not operate correctly and the device using the servo mechanism 1 may malfunction.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a servo valve capable of extremely easily removing foreign matter that has entered the tip end portion of a flapper nozzle and obtaining an appropriate operation. Has an aim.

[0005]

A servo valve according to a first aspect of the present invention is a servo valve having a flapper and a flapper nozzle for maintaining the flapper at positions spaced apart by a pressure of fluid, the flapper nozzle comprising: A first nozzle portion provided at a predetermined interval with respect to the flapper and slidable in the axial direction of the flapper nozzle, and a second nozzle portion provided at an interval larger than the predetermined interval. And the first nozzle portion is urged in the flapper direction by urging means. The servo valve of the second invention is characterized in that the sliding speed of the first nozzle portion of the first invention is damped by a damper.

A servo valve according to a third aspect of the present invention is a servo valve having a flapper and a flapper nozzle for maintaining the flapper at positions spaced apart by a predetermined pressure by fluid pressure, wherein the flapper nozzle is provided with respect to the flapper. A first nozzle portion provided with a predetermined interval and a second nozzle portion provided with an interval larger than the predetermined interval, and the flapper has the first nozzle portion. A plate body slidably provided in the axial direction of the flapper nozzle at a position facing the flapper nozzle, and the plate body is biased in the flapper nozzle direction by a biasing means. There is. A servo valve of a fourth invention is characterized in that the sliding speed of the plate body of the third invention is damped by a damper.

[0007]

According to the servo valve of the first invention, when foreign matter is caught between the flapper and the first nozzle portion when the flapper is moved toward the first nozzle portion by an external force, The first nozzle portion slides against the biasing force, and the interval between the second nozzle portion and the flapper is narrowed.

As a result, the flapper is moved in the direction away from the flapper nozzle by the pressure of the fluid in the flapper nozzle, and the first nozzle portion is also slid in the flapper direction by the biasing means. At this time, since the flapper is moved first, the sliding of the first nozzle portion in the flapper direction by the biasing means is delayed compared to the movement of the flapper, and thus the distance between the first nozzle portion and the flapper is increased. The foreign material that has spread and is caught is dropped and eliminated.

According to the servo valve of the second invention, in addition to the first invention, the sliding of the first nozzle portion by the urging means is further delayed by the damper, so that the first nozzle portion is further delayed. The distance between the flapper and the flapper can be expanded reliably.

According to the servo valve of the third invention, when the flapper is moved toward the flapper nozzle by an external force,
When a foreign substance is caught between the flapper and the first nozzle portion, the flapper plate is slid against the urging force of the urging means, and the distance between the second nozzle portion and the flapper is narrowed.

As a result, the flapper is moved in the direction away from the flapper nozzle by the pressure of the fluid in the flapper nozzle, and the plate member is slid toward the first nozzle portion by the biasing means. At this time, since the flapper body is moved earlier than the plate body, the sliding of the plate body in the direction of the first nozzle portion by the biasing means is delayed compared to the movement of the flapper body.
As a result, the gap between the first nozzle portion and the plate body is expanded,
The foreign matter that was sandwiched is dropped and eliminated.

According to the servo valve of the fourth invention, in addition to the third invention, the sliding of the plate body by the urging means is further delayed by the damper, so that the first nozzle portion and the plate body are further delayed. The space between and can be reliably expanded.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the servo valve of the present invention will be described below with reference to the drawings. The same parts as those of the conventional example are designated by the same reference numerals and the description thereof will be omitted. First, the servo valve of the first embodiment will be described with reference to FIG. In the figure, reference numeral 11
Is a servo valve of the present embodiment, and reference numeral 12 is a flapper nozzle.

The flapper nozzle 12 has a nozzle body (second nozzle portion) 13 and a flow passage 18 at the center, and a slide nozzle (first nozzle) which is slidably provided at the tip of the nozzle body 13. Nozzle portion) 14, and a space portion 15 is formed between the slide nozzle 14 and the nozzle body 13.

A spring (biasing means) 16 is provided in the space portion 15, and the spring 16 constantly biases the slide nozzle 14 toward the distal end portion. A locking piece 17 is provided on the inner peripheral side near the tip of the nozzle body 13, and the locking piece 17 is provided.
The slide nozzle 14 urged by the spring 16 toward the tip portion is locked so that the slide nozzle 14 does not drop from the tip portion of the nozzle body 13.

Further, between the outer periphery near the tip of the slide nozzle 14 and the inner periphery of the nozzle body 13, and between the outer periphery near the rear end of the slide nozzle 14 and the inner periphery of the nozzle body 13, Flow paths 20 and 20 formed of gaps are formed respectively. Then, the flapper nozzle 1 having the above configuration
In the servo valve 11 including 2 and the flapper 6, the distance between the tip of the slide nozzle 14 and the flapper 6 becomes Δx due to the supply of fluid, and the distance between the tip of the nozzle body 13 and the flapper 6 becomes larger than Δx. It has a large Δz.

Next, the operation of the servo valve 11 having the above structure will be described with reference to FIG. When the external force F acts on the lever 2, the lever 2 is swung about the fulcrum 3 and the distance Δx between the flapper nozzle 12 of the servo valve 11 and the flapper 6 is narrowed. Then, by narrowing this interval Δx, the pressure in the space 7 inside the flapper nozzle 12 increases, and a difference in pressure with the space 8 occurs. This allows
The piston 9 moves in the direction of arrow B in FIG. 4, and the distance Δx between the flapper 6 and the tip of the flapper nozzle 12 is returned to the predetermined distance.

When foreign matter is mixed in the fluid supplied to the flow path 18 of the flapper nozzle 12 through the space 7, the foreign matter is mixed with the tip of the slide nozzle 14 of the flapper nozzle 12 and the flapper 6. It may be sandwiched between and. At this time, according to the servo valve 11 of the present embodiment, the following operation is performed to remove the foreign matter sandwiched between the tip end of the slide nozzle 14 and the flapper 6.

The tip of the slide nozzle 14 and the flapper 6
When an external force F acts on the lever 2 with a foreign substance sandwiched between the flap nozzle 6 and the flapper 6, the gap Δx between the tip of the slide nozzle 14 and the flapper 6 does not decrease, and the slide nozzle 14 and the flapper 6 are attached to the spring 16. Contrary to the influence, it is moved in the direction of arrow B in FIG. As a result, the flapper 6
The distance Δz between the flapper 6 and the tip of the nozzle body 13 is narrowed with the movement of. At this time, the space 15 between the nozzle body 13 and the slide nozzle 14
The fluid therein flows out from the flow paths 20, 20.

By narrowing this interval Δz, the pressure in the space 7 inside the flapper nozzle 12 rises, and a pressure difference with the space 8 occurs, and the piston 9 moves in the direction of arrow a in FIG. , The interval Δz is expanded. Further, when the flapper 6 moves, the slide nozzle 14 also follows the tip end direction (direction of arrow C in FIG. 1) by the urging force of the spring 16.

At this time, first, since the flapper 6 is moved, the slide nozzle 14 is moved slightly later than the movement of the flapper 6, and when the slide nozzle 14 moves toward the tip end portion. In addition, since the fluid gradually flows from the flow paths 20, 20 into the space 15 in which the spring 16 between the slide nozzle 14 and the nozzle body 13 is accommodated, the spring 16 moves the slide nozzle 14 in the flapper 6 direction. Is further delayed.
That is, the flow paths 20 and 20 function as a damper that delays the sliding of the slide nozzle 14.

As a result, the distance Δx between the tip of the slide nozzle 14 and the flapper 6 is slightly widened, and the foreign matter sandwiched between the tip of the slide nozzle 14 and the flapper 6 falls off and is eliminated. To be done. As described above, according to the servo valve 11 of the above-described embodiment, even if the foreign matter mixed in the fluid supplied to the flapper nozzle 12 is caught between the tip portion of the slide nozzle 14 and the flapper 6,
The foreign matter can be removed very easily while maintaining the function of the servo valve 11, and the malfunction of the servo mechanism 1 due to the entrapment of the foreign matter can be surely prevented, and the reliability of the servo mechanism 1 is greatly improved. Can be made.

Next, the servo valve of the second embodiment will be described with reference to FIG. As shown in the figure, this servo valve 2
The flapper nozzle 22 constituting the first nozzle is a nozzle body (second
Nozzle part) 23 inside the nozzle part (first nozzle part)
24 is formed, and the fluid is ejected from the tip of the nozzle portion 24. The distance between the tip of the nozzle portion 24 and the flapper 6 is Δx, and the distance between the tip of the nozzle body 23 and the flapper 6 is Δz, which is larger than Δx.

Further, in the flapper 6 of this embodiment, a concave portion 25 is formed in the flapper body 6a at a position facing the nozzle portion 24 of the flapper nozzle 22, and the concave portion 25 is formed.
Is provided with a plate 26 that is slidable in the axial direction of the flapper nozzle 22, and a locking piece 29 attached to the opening edge prevents the plate 26 from falling out of the recess 25. There is. Further, between the bottom portion 25a of the recess 25 and the plate body 26, a spring (biasing means) 27 for urging the plate body 26 toward the nozzle portion 24, and the plate body 2 are provided.
And a damper 28 for damping the sliding speed of No. 6 are provided.

Then, the servo valve 2 thus constructed
In the case of 1, the external force F acts on the lever 2 and the flapper 6 causes the flapper 6 to operate when the foreign matter is sandwiched between the tip end of the nozzle portion 24 of the flapper nozzle 22 and the plate body 26 of the flapper 6. When moved toward the nozzle 22, the plate 26
Since foreign matter is sandwiched between the nozzle 24 and
The plate member 26 is not moved in the direction of the nozzle portion 24, but only the flapper body 6a is moved in the direction of the flapper nozzle 22 (direction of arrow D in FIG. 2).

That is, as the flapper 6 moves, the plate member 26 moves in the recess 25 in the direction of the bottom 25a of the recess 25 against the biasing force of the spring 27. As a result, the gap Δz between the flapper body 6a and the nozzle body 23 is narrowed, the pressure in the space portion 7 inside the flapper nozzle 22 is increased, and the pressure in the space portion 8 becomes different, and the piston 9 moves in the direction of the arrow in FIG. In the direction a, the flapper 6 moves in a direction away from the flapper nozzle 22 (direction indicated by arrow E in FIG. 2).

When the flapper 6 moves, the plate body 26 moves toward the nozzle portion 24 due to the urging force of the spring 27, but the movement of the plate body 26 by the spring 27 is slightly delayed. That is, the movement of the plate 26 is further delayed by the action of the damper 28.

As a result, the distance Δx between the tip of the nozzle 24 and the plate 26 is slightly widened, and the foreign matter sandwiched between the tip of the nozzle 24 and the plate 26 falls off. Are eliminated. As described above, according to the servo valve 21 of the above-described embodiment, the foreign matter mixed in the fluid supplied to the flapper nozzle 22 is trapped between the tip portion and the flapper 6 as in the first embodiment. Even if this is the case, it is possible to very easily remove this foreign substance while maintaining the function of the servo valve 21, and it is possible to reliably prevent malfunction of the servo mechanism 1 due to the entrapment of this foreign substance, and to improve the reliability of the servo mechanism 1. Can be significantly improved.

In the above embodiment, the slide nozzle 1
Although the springs 16 and 27 are used as the urging means for urging the plate 4 or the plate body 26, the size can be reduced by using the plate springs instead of the springs 16 and 27. Also, hydraulic pressure may be used as the biasing means by the springs 16 and 27. That is, in the above-described embodiment, pressure oil is supplied into the space portion in which the springs 16 and 27 are housed, instead of the springs 16 and 27, and the slide nozzle 14 or the plate 26 is biased by the pressure oil. Is also good.

Further, in the above embodiment, the sliding speed of the slide nozzle 14 or the plate body 26 is attenuated by the flow passage 20 or the damper 28 functioning as a damper to move the slide nozzle 14 or the plate body 26, respectively. The flow path 20
Alternatively, without providing the damper 28, the slide nozzle 1
4. Even with a slight delay in the follow-up of the plate member 26 by the springs 16 and 27, the distance between the slide nozzle 14 and the flapper 6 or the distance between the plate member 26 and the nozzle portion 24 can be increased to reliably remove foreign matter. Of course you can.

The servo mechanism using the servo valves 11 and 21 of the above embodiment is not limited to the embodiment, and may be used in the electro-hydraulic servo mechanism shown in FIG. 3, for example. Here, in FIG. 3, reference numeral 31 is a torque motor that changes the input current into torque, and reference numeral 32 is the hydraulic device 3.
6 is a spool driven by hydraulic pressure from 6. The torque motor 31 is a kind of DC electromagnet, and is adapted to convert an input current supplied to a coil 34 wound around a torsion spring 33 for torque transmission into torque by electromagnetic force. The spool 32 is driven by the converted signal pressure from the flapper 6 to be displaced, and the feedback spring 35 arranged at the end of the flapper 6 is acted on by the feedback torque due to the displacement of the spool 32. It has become.

Further, in the above embodiment, the servo valve 1 having a structure in which the fluid is ejected from the flapper nozzles 12 and 22.
1 and 21 have been described as an example, this servo valve 11,
As a reference numeral 21, it is needless to say that it can be applied to a servo valve of a type in which a fluid is introduced into the flapper nozzle and the flapper provided in the flapper nozzle is drawn into the nozzle, that is, a negative type servo valve. .

[0033]

As described above, according to the servo valve of the present invention, the following effects can be obtained. According to the first or third aspect, even if foreign matter is caught between the flapper nozzle's first nozzle portion and the flapper, the gap between the flapper nozzle's first nozzle portion and the flapper is maintained while maintaining the function of the servo valve. Alternatively, the foreign matter can be removed very easily by expanding the distance between the first nozzle portion and the flapper plate, and the malfunction of the servo mechanism due to the entrapment of the foreign matter can be reliably prevented, and the reliability of the servo mechanism can be improved. It is possible to significantly improve the sex.

Further, according to the second or fourth aspect of the invention, since the sliding speed of the plate of the first nozzle portion or the flapper can be attenuated by the damper, the gap between the first nozzle portion and the flapper can be reduced. Alternatively, the gap between the first nozzle portion and the plate body can be expanded more easily to more reliably remove the foreign matter.

[Brief description of drawings]

FIG. 1 is a sectional view of a servo valve illustrating a configuration and a structure of a servo valve according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a servo valve for explaining the configuration and structure of the servo valve of the second embodiment of the present invention.

FIG. 3 is a schematic configuration diagram of a servo mechanism for explaining an example of another servo mechanism using a servo valve.

FIG. 4 is a schematic configuration diagram of a servo mechanism for explaining an example of a servo mechanism using a servo valve.

[Explanation of symbols]

 6 flapper 11, 21 servo valve 12, 22 flapper nozzle 13, 23 nozzle body (second nozzle part) 14 slide nozzle (first nozzle part) 16, 27 spring (biasing means) 20 flow path (damper) 26 Plate 28 damper

Claims (4)

[Claims] 1. A servo valve having a flapper and a flapper nozzle for maintaining the flapper at a position spaced apart by a pressure of a fluid, wherein the flapper nozzle is spaced apart from the flapper by a predetermined distance. A first nozzle part slidably provided in the axial direction of the nozzle, and a second nozzle part provided with a gap larger than the predetermined gap, the first nozzle part Is a servo valve which is biased in the flapper direction by a biasing means. 2. The servo valve according to claim 1, wherein a sliding speed of the first nozzle portion is damped by a damper. 3. A servo valve having a flapper and a flapper nozzle for maintaining the flapper at a position spaced apart by a fluid pressure, wherein the flapper nozzle is provided at a predetermined distance from the flapper. A first nozzle part and a second nozzle part provided with a space larger than the predetermined space, and the flapper is provided at a position facing the first nozzle part.
A servo valve comprising a plate body slidably provided in an axial direction of the flapper nozzle, the plate body being biased in the flapper nozzle direction by a biasing means. 4. The servo valve according to claim 3, wherein a sliding speed of the plate body is damped by a damper.