JPS61197805A - Fluid pressure servo valve - Google Patents

Abstract

PURPOSE:To securely move a main valve with low power by changing fluid pressure applied to the main valve by means of a nozzle flapper and coupling the main valve with a nozzle by means of an elastic body. CONSTITUTION:A nozzle 36 is bored in a rod-shaped member 34 connected to a first oil path 42, a flapper 30 is fixed at a position, of a leaf spring 28, in opposition to the nozzle 36, and a central portion of the rod-shaped member 34 is coupled with one end of a rod 20 via a feedback spring 38. Hereby, the main valve 12 is moved by fluid pressure without directly moving the main valve 12 by means of a forcing motor, whereby the main valve 12 can securely be moved with low power an furthermore the valve can be miniaturized since there is no need to provide the core of a displacement gauge.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fluid pressure servo valve, and more particularly to a two-stage servo valve driven by a force motor.

[Conventional technology]

As shown in U.S. Patent No. 4=215g723, conventional servo valves have a main valve that is housed in a body and is movable, a force motor that directly drives the main valve, and a feedback control system. Yo .

In order to maintain the position of the main valve at a predetermined position, the main valve is equipped with a flow change needle core that detects the position of the main valve. This servo valve is
Because it uses a force motor button air-core coil, it has the feature of high responsiveness, so it is used particularly in fields where it is necessary to drive large-diameter main valves.

[Problem that the invention seeks to solve]

However, the Sarze Susumuφ equipped with the conventional large diameter main valve!
, In the middle of the test, I also have seven fortunes.

In addition, the force motor's magnet part is large, and the servo valve itself is large because it is equipped with a displacement gauge core for feedback control, making it difficult to use in fields where compactness is required. There was a problem that. On the other hand, if you try to make the servo valve itself smaller by making the force motor magnet smaller, the amplifier
Since it is necessary to increase the size of 9W, there is a problem in that it becomes large or small.

The present invention was made in order to solve the above problems, and by adopting mechanical feedback control instead of electrical feedback control using a displacement meter core, it is possible to reduce the size and power of fluid pressure. The purpose is to provide servo valves.

[Failure to solve the problem]

In order to achieve the above object, the present invention provides a fluid pressure servo valve in which flow paths are switched by movement of a main valve.
A fluid resistance converter that changes fluid resistance and displaces the fluid pressure acting on the main valve is configured by a valve body moved by the SIOUS motor and a flow path formed in a member that can be deformed or moved in the movement direction of the main valve. In addition, an elastic body is interposed between the main valve and the member so that the movement of the main valve is transmitted to the member of the fluid resistance converter.

[For production]

According to the present invention, when the valve body is moved by the force motor, the fluid resistance of the fluid resistance converter changes, and the fluid pressure acting on the main valve changes. This change in fluid pressure causes the main valve to move toward the low pressure chamber.

Movement of the main valve is transmitted to a member of the fluid resistance converter through the elastic body, deforming or moving this member. The fluid resistance of the fluid resistance converter changes due to the deformation or movement of the member, and the movement of the main valve is stopped when the fluid resistance reaches its original size. That is, the main valve is moved by fluid pressure to a position proportional to the position of the valve body moved by the force motor.

〔Effect of the invention〕

As explained above, according to the present invention, the main valve is moved by fluid pressure without being moved directly by the force motor, so the main valve can be moved reliably with a small or small machine. Also, since no displacement meter core is provided, the device can be made smaller.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.
FIG. 1 shows a sectional view of a fluid pressure servo valve according to a first embodiment of the present invention. A main valve 12 is housed inside the body 1° so as to be movable in the axial direction. The body 10 has pressure ports Ps, /-A connected to a hydraulic pumper.
t B and return port R are drilled. A piston 14 is fixed to one end of the main valve 12, and the piston 14 divides the inside of the body 10 into a first chamber 16 and a second chamber 18. A rod 2 with a diameter smaller than that of the main valve 12 is mounted on the side end face.
0 is fixed. This rod 2o passes through the valve body 10 and extends in the axial direction of the main valve 12. In this embodiment, the pressure receiving surface of the piston 14 on the first chamber 16 side is
A force motor storage chamber 32 is provided at the end of the housing 10 in which the diameter of the rod 20 is set to be twice that of the pressure receiving surface on the second chamber 18 side of the fourth chamber. The force motor is housed in. This force motor is composed of a core 22 housed at the end of the body, and a pobbin 26 around which a coil 24 is wound and inserted into the core 22. This bobbin 26
is supported by a leaf spring 28 whose peripheral edge is fixed to the inner wall of the body 10. A flat/arm 30 is fixed to the center of the leaf spring 28, which acts as a main body. A rod-shaped member 34 made of a hollow flexible member is provided in the force motor storage chamber 32, and both ends of this rod-shaped member 340 are fixed to the inner wall of the force motor storage chamber 32. Further, a nozzle 36 is bored in the rod-shaped member 34 at a position facing the flannel 430. Furano above! 3Q and the nozzle 36 constitute a fluid resistance converter. A central portion of the rod-shaped member 34 is connected to one end of the rod 20 fixed to the piston 14 via a feedback spring 38. The force motor storage chamber 32 is communicated with the oil tank through a return date R bored in the body 10. Note that 4o is a connector that supports a lead wire for exciting the coil 24.

The pressure Pg is applied to the rod-shaped member 3 through the first oil passage 42.
4 and the second chamber 18 via the first and second oil passages 44.

Further, the first oil passage 42 is provided with an adjustable throttle 48 , and the first oil passage 42 is communicated with the first chamber via a branch oil passage 46 .

Next, the operation of this embodiment will be explained. The pressure oil generated by the hydraulic pressure I is introduced into the first chamber 16 from a pressure of $-) Pa through the throttle shaft 48, the first oil passage 42, and the branch oil passage 46, and is also introduced into the second oil It is introduced into the second chamber 18 via a channel 44 . Further, the pressure oil introduced into the first oil passage 42 is returned to the oil tank via the cavity of the rod-shaped member 34, the nozzle, the force motor storage chamber 32, and the return/torque R. In this case, the hydraulic pressure per unit area acting on the pressure receiving surface on the 10th chamber 16 side of the piston 14 is
Due to the resistance of Since it is larger than the side pressure receiving surface, the hydraulic pressure acting on both pressure receiving surfaces of the piston 7140 is balanced, and the main valve 12 is held at a predetermined position.

The balance of this oil pressure can be adjusted by the throttle valve 48. In the above state, the current flowing through the coil 24 of the force motor is controlled to attract the brush 130 against the elastic force of the leaf spring 28, and the flange z43 When the gap between Q and the nozzle 36 is increased, the fluid resistance of the fluid resistance converter becomes smaller, more pressure oil passes through the nozzle 36, and the hydraulic pressure acting on the pressure receiving surface of the first chamber 16 side of the piston 14 becomes smaller. Become. On the other hand, since the hydraulic pressure from the pressure port P8 is acting on the second chamber 18 side pressure receiving surface of the piston 14, a difference occurs in the hydraulic pressure acting on both pressure receiving surfaces of the piston, and this hydraulic pressure difference causes the main valve 12 to It is moved to the low pressure side, that is, the first chamber 16 side.

This movement of the main valve 12 is transmitted to the rod-shaped member 34 via the rod 20 and the feedback spring 38, causing the rod-shaped member 34 to deform. Due to the deformation of the rod-shaped member 34, the gap between the flange 930 and the nozzle 36 becomes smaller, and the fluid resistance increases.

Then, when the magnitude of the fluid resistance of the fluid resistance converter reaches the original magnitude K, the hydraulic pressure acting on both pressure receiving surfaces of the piston is balanced, and the movement of the balance main valve 12 is stopped.

On the other hand, if the current flowing through the force motor coil is controlled to reduce the gap between the furan 30 and the nozzle 36,
The fluid resistance of the fluid resistance converter increases, and the amount of pressure oil passing through the nozzle 36 decreases, causing the first chamber 1 of the piston 14 to
The hydraulic pressure acting on the 6th side pressure receiving surface increases. On the other hand, since the hydraulic pressure from the pressure port Pe is acting on the second chamber 18 side pressure receiving surface of the piston 14, a difference occurs in the hydraulic pressure acting on both pressure receiving surfaces of the piston, and this hydraulic pressure difference causes the main valve 12 to It is moved to the low pressure side, that is, to the second chamber 18 side.

The force is transmitted to the rod-shaped member 34 via the dopak spring 38, causing the rod-shaped member 34 to deform. Due to the deformation of the rod-shaped member 34, the gap between the flange 130 and the nozzle 36 becomes larger, and the fluid resistance becomes smaller. Then, when the fluid resistance of the fluid paper ii'c variable body reaches its original magnitude, the hydraulic pressure acting on both pressure receiving surfaces of the piston is balanced and the movement of the main valve is stopped.

As explained above, according to this embodiment, the main valve is moved by quickly applying a pressure change using a small displacement by the force motor, and 1. Since the movement of the main valve can be feedback-controlled by moving the main valve with a large driving force, the main valve can be moved stably. Further, by increasing the elastic coefficients of the rod-shaped member and the feedback spring, feedback control can be extremely stabilized, and highly accurate positioning control can be performed.

Next, a second embodiment of the present invention will be described with reference to FIG. Note that in FIG. 2, parts corresponding to those in FIG. 1 are designated by the same reference numerals, and explanations thereof will be omitted. Fallen. A compression spring 52 is interposed between the support plate 50 and the core 22, and a spool 54 is fixed to the support plate 50 so as to protrude in the axial direction of the main valve 12. A sleeve 56 is housed in the force motor housing chamber 32 on the first chamber 16 side. This sleeve 56 is composed of the core 22 and the sleeve 5.
compression spring 5 and piston 14 interposed between
It is supported by a feedback spring 38 interposed between the sleeve 56 and the sleeve 56 . The sleeve 56 includes a flow path 58 that communicates the first oil path 42 and the return port R;
A branch oil passage 60 is formed that communicates the first oil passage 42 with the force motor storage chamber 32 and the first chamber 16.

The spool 54 described above is inserted into the sleeve 32 to change the flow path resistance of the flow path 58. Here, the spool 54 and the flow path 58 formed in the sleeve 56 constitute a fluid resistance converter.

The operation of this embodiment will be explained below. The pressure oil generated in the hydraulic tank is transferred from the pressure port Ps to the throttle 48 and the first oil path 4.
2 and the branch oil passage 60 into the first chamber 16 and the force motor storage chamber 32, and the second oil passage 44 into the second chamber 18).
The pressure oil introduced into the second oil passage 42 is returned to the oil tank via the flow passage 58 of the sleeve 56 and the return port R. In this case, the magnitude of the hydraulic pressure acting on both pressure receiving surfaces of the sleeve 560 is equal, and the magnitude of the hydraulic pressure acting on both pressure receiving surfaces of the piston 7140 is equal, so the sleeve 560
6 and main valve 12 do not move.

In the above state, when the spool 54 is moved in the axial direction by the force motor, the fluid resistance of the fluid resistance converter changes, and the amount of pressure oil passing through the flow path 58 changes. This change in the flow rate of the pressure oil causes a hydraulic pressure difference between both pressure receiving surfaces of the piston 14, and this hydraulic pressure difference moves the main valve 12 toward the low pressure chamber. In this case, since the first chamber 16 and the force motor storage chamber 32 are communicated with each other by the branch oil passage 60, there is no oil pressure difference between the pressure receiving surfaces of the sleeve 560, and the sleeve 56 cannot be moved depending on the oil pressure. Not done.

Movement of main valve 12 causes sleeve 56 to move via feedback spring 38. The movement of the sleeve 560' changes the fluid resistance of the fluid resistance converter, and when the fluid resistance reaches its original size, the hydraulic pressures acting on both pressure receiving surfaces of the piston are balanced and the movement of the main valve 12 is stopped.

As explained above, according to this embodiment, similarly to the first embodiment, the main valve is moved by quickly applying a pressure change by a small displacement by the force motor, and the main valve is moved by moving the main valve with a large driving force. Since the movement of the main valve can be feedback-controlled, the main valve can be moved stably. Also,
By increasing the elastic coefficients of the compression spring and the feedback spring, feedback control can be extremely stabilized, and highly accurate positioning control can be performed.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a servo valve according to a first embodiment of the present invention;
FIG. 2 is a sectional view of a servo valve according to a second embodiment of the present invention. 12... Main valve, 3o... Fran arm, 3
6... Nozzle, 54... Spool, 56...
··sleeve. Agent Tatsuyuki Unuma Figure 1 Figure 2

Claims (3)

[Claims] (1) In a fluid pressure servo valve in which the flow path is switched by movement of the main valve, the flow path is formed in a member that can be deformed or moved in the direction of movement of the valve body and the main valve moved by a force motor. a fluid resistance converter that changes the fluid pressure acting on the main valve by changing the fluid resistance by the passageway, and a fluid resistance converter configured such that the movement of the main valve is transmitted to the members of the fluid resistance converter. A fluid pressure servo valve characterized in that an elastic body is interposed between the main valve and the member. (2) Claim (1), wherein the fluid resistance converter is constituted by a flapper moved by a force motor and a nozzle formed in a flexible member that can be deformed in the direction of movement of the main valve. Fluid pressure servo valve. (3) Claim (1) wherein the fluid resistance converter is constituted by a spool moved by a force motor and a flow path formed in a sleeve supported by a spring so as to be movable in the moving direction of the main valve. The fluid pressure servo valve described.