JPH025924B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a force motor type fluid pressure servo valve using a drive line wheel, and in particular improves responsiveness by reducing the weight of the drive wheel support member. Regarding servo valves.

[Conventional technology]

A force motor type servo valve using a drive line directly connects the drive line and the spool, the force generated in the drive line directly drives the spool, and the spool opens and closes the fluid flow path. . This servo valve will be further explained with reference to the drawings.

FIG. 1 is a diagram showing a schematic configuration of a commonly used force motor type fluid pressure servo valve.

In FIG. 1, the servo valve includes a force motor 10 as a driving force generator and a force motor 1.
0, the direction of fluid flow, the flow rate,
It is composed of a valve section 12 that controls pressure and the like.

The valve part 12 has a spool 14, a sleeve 16, and a valve body 18 as its main components, and controls the direction and flow rate of the fluid flowing into the flow paths 20a to 20e by controlling the relative position of the spool 14 with respect to the sleeve 16 with high precision. Or control pressure etc.

On the other hand, the force motor 10 has a magnet 2
2, yoke 24, pole 26, said spool 14
The main components are a drive line wheel support member 28 fixed to the end of the drive line wheel support member 28 and a drive line ring 30 attached around the drive line wheel support member 28. The direction and magnitude of the force generated in the axial direction of the spool 14 are controlled by controlling the force. That is, magnet 22, yoke 2
4. A magnetic path is formed by the pole 26, and a force for driving the spool 14 and the drive line wheel support member 28 is generated by passing current to the drive line wheel 30 placed in this magnetic path. The magnitude of this generated force F (=
Bli) is proportional to the magnetic flux density B, the effective length l of the coil, and the magnitude of the current i. The force F generated in the drive line wheel 30 in this manner is transmitted to the spool 14 of the valve portion 12 via the drive line wheel support member 28, and drives this spool 14. An elastic body 32 interposed between the left end surface of the pole 26 in FIG.
A displacement is applied to the spool 14 in proportion to the force F generated. When the force F is not generated on the drive line wheel 30 due to the action of this elastic body 32, the spool 14
is held in a neutral position. In addition, the drive line wheel 3
By displacing the spool 14 in proportion to the force F generated at zero, the flow rate or pressure of the fluid is controlled.

FIG. 2 shows a partial cross-sectional view of the drive line wheel 30 and drive line wheel support member 28 of a conventionally used servo valve. A drive line wheel support member 28 is attached to the end of the spool 14 by a bolt 34. The drive line wheel 30 is wound around a recess provided on the outer periphery of the support member 28 and fixed with an adhesive 38. The end 40 of the drive line wheel is connected to a terminal 42
Fixed. Lead wire 4 from terminal 42
4 is drawn out, and a command current is supplied to this lead wire 44. Note that the insulator 46 is
8 and the terminal 42.

The movable part is composed of the spool 14, the drive line wheel 30, and the drive line wheel support member 28, and the weight of this movable part is the sum of these weights. Each member 1
4, 30, and 28 are designed to be as light as possible from the viewpoint of the responsiveness of the servo valve and the efficiency of the force motor.

The reason for reducing the weight of each component in this way is the first
This is because if the force generated by the drive line wheels is constant, the smaller the weight of the movable part, the greater the acceleration can be obtained, and the responsiveness will be improved. The second reason is that
This movable part is urged in one direction by an elastic body 32, and in order to make the natural frequency of this system above a certain value, the spring constant of the elastic body 32 is increased in proportion to the weight of the movable part. However, given the constant output of the force motor, the weight of the moving part is small, which means that the spring constant can be selected to be small to achieve the same natural frequency, which is advantageous as it allows for a large displacement of the spool. This is because there is an advantage.

[Problem that the invention seeks to solve]

However, the dimensions of the spool are determined by the required flow rate of the servo valve, and the length l and the diameter of the drive line 30 are determined by the required output of the force motor. Therefore, there is a limit to the weight reduction of the spool 14 and the drive line wheel 30.

On the other hand, as for the drive line wheel support member 28, it is desirable to reduce the weight as much as possible for the above-mentioned reasons, as long as the purpose of transmitting the force generated in the drive line wheel 30 to the spool is achieved. For this reason, conventionally, the drive line wheel support member 28 has been constructed using a lightweight alloy, such as an aluminum alloy. Therefore, when comparing the weights of each member, the weight of the drive line wheel support member 28 is equal to that of the drive line wheel 30 and the spool 14.
It was several times the weight of .

For this reason, in the case of conventional servo valves, most of the force for accelerating the movable part is applied to the drive line wheel support member 2.
8, the effective force for accelerating the spool 14 is reduced, resulting in extremely poor efficiency.

Next, the natural frequency fn of the movable part is determined based on the responsiveness required of the servo valve. This natural frequency fn is given by the mass m of the movable part and the spring constant k of the elastic body 32 that supports this movable part, as fn=k/m. In order to keep this natural frequency fn above a certain value, the heavier the movable part, the larger the spring constant k must be. In addition, the force motor output F,
The relationship between the spool displacement x and the acceleration of the movable part is F=kx, and in order to secure the necessary amount of spool displacement x, the output F of the force motor had to be increased. Increasing the output F of the force motor means increasing the size of the force motor, which poses a problem in that the weight of the movable part increases. In other words, it is necessary to reduce the weight of the movable parts, especially the drive line wheel support member 28, either from the viewpoint of response or from the viewpoint of natural frequency.

The present invention was made in order to eliminate the problems of the conventional servo valves, and an object of the present invention is to provide a servo valve in which the weight of the drive line wheel support member of the movable part of the servo valve is reduced.

[Means for solving problems]

The present invention, which solves the above-mentioned problems, includes a valve body having a flow path formed therein, and a valve portion including a spool that is slidably disposed within the valve body and opens and closes the flow path.
An end of a driveline wheel support member is fixed to the spool of the valve portion, and the driveline wheel support member is biased in one direction by an elastic body, and a driveline wheel is attached to the driveline wheel support member. This drive line wheel portion is arranged in a magnetic path including a magnetic yoke and a pole, and by passing a current through the drive line wheel, the spool and drive line are moved against the biasing force of the elastic body. In the servo valve, the drive line wheel support member is integrally formed by embedding the drive line ring inside fiber-reinforced plastic. It is characterized by being formed.

[Effect]

The movable part of the servo valve consists of a spool, a drive line wheel, and a drive line wheel support member, and the weight of this movable part is the sum of the weights of the above-mentioned members. The lighter the weight of the movable part, the better the responsiveness and the efficiency of the driving force generating section. Comparing the weight of each member of the movable part, it was found that the drive line wheel support member weighs several times as much as the other members. Furthermore, in order to achieve high response, the smaller the inductance component of the drive line, the faster the rise of the current flowing into the drive line. Therefore, the drive line wheel supporting member is integrally formed by embedding the drive line inside the fiber plastic, thereby reducing the weight and the inductance.

As a result, the weight of the drive line wheel support member that transmits the driving force generated in the drive line wheel to the spool can be reduced, and the current rises quickly, resulting in high responsiveness and improved efficiency of the drive force generating section. become. Furthermore, since the drive line ring is embedded inside the fiber-reinforced plastic, the drive line ring is not damaged from the outside.This allows the magnetic path gap between the drive line ring portions to be reduced, and the magnetic flux in this gap area Density can be increased.

〔Example〕

Preferred embodiments of the servo valve according to the present invention will be described in detail below with reference to the accompanying drawings.

First Embodiment FIG. 3 is a sectional view showing the structure of an embodiment of a servo valve according to the present invention.

In the embodiment shown in FIG. 3, the same or similar members in the servo valve shown in FIGS. 1 and 2 are designated by the same reference numerals, and detailed explanation thereof will be omitted.

In the embodiment shown in FIG.
8 is composed of a coil bobbin 48 in which the drive line wheel 30 is embedded, and a core member 50 for fixing the drive line wheel support member 28 to the spool 14. The coil bobbin 48 is made of lightweight synthetic resin, such as fiber-reinforced plastic. The core member 50 is formed using a lightweight alloy, such as an aluminum alloy. In the embodiment shown in FIG.
The terminal 42 is also embedded in the coil bobbin 48, and the drive line wheel 30 is also embedded in the coil bobbin 48.
The end 40 of the coil bobbin 48 is connected to a terminal 42 inside the coil bobbin 48 . Therefore, the insulation and adhesion of the drive wire 30 are automatically performed during the manufacturing process of the coil bobbin 48, and there is no need to perform them in a separate process.

Further, in the embodiment shown in FIG. 3, the core member 50 is provided with a collar 52, and the core member 50 and the coil bobbin 4 are
Connect with 8. By adopting such a connection structure, loosening between the coil bobbin 48 and the core member 50 due to a difference in coefficient of thermal expansion due to a temperature change of the drive wire 30 can be eliminated.

According to the embodiment shown in FIG. 3, the driveline wheel support member 28 is composed of a coil bobbin 48 and a core member 50, and the coil bobbin 48 is made of fiber-reinforced plastic, so that the driveline wheel support member 28 is composed of a coil bobbin 48 and a core member 50. It is possible to reduce the weight of the support member 28 by about 30% compared to a conventional drive line wheel support member while having sufficient strength, and the force generated by the force motor can be efficiently transmitted to the spool. Therefore,
Since the natural frequency fn of the movable part of the servo valve increases, the displacement of the spool 14 of the servo valve can be increased, and as a result, the control flow rate of the servo valve can be increased.

Furthermore, in the embodiment shown in FIG. 3, the coil bobbin 48 is made of fiber-reinforced plastic and the drive wire ring 30 is embedded in the coil bobbin 48, so that the thickness t of the coil bobbin 48 can be reduced. As a result, the gap between the pole 26 and the yoke 24 can be made smaller, the magnetic flux density B in this part becomes larger, and the output of the force motor can be improved.

Conventionally, the attachment part of the drive line wheel 30 of the drive support member 28 was done by machining.
It was impossible to form the coil bobbin 48 below a certain thickness, but by making the coil bobbin 48 from fiber-reinforced plastic as in the above embodiment, the thickness t could be reduced compared to the conventional thickness. It is possible to make it significantly thinner.

Second Embodiment FIG. 4 shows another embodiment according to the present invention. In the embodiment shown in FIG. 4, the drive line wheel support member is composed of a coil bohin 48 and a core member 50,
Embedding the drive wire 30 inside the coil bobbin 48 and embedding the terminal 42 in the coil bobbin 48 is similar to the embodiment shown in FIG. 3, but in the embodiment shown in FIG. The difference is that 40 is connected to a terminal 42 on the outside of the coil bobbin 48.

Third and Fourth Embodiments FIGS. 5 and 6 show still other embodiments of the present invention. In the embodiment shown in FIGS. 3 and 4, the drive line wheel support member 28
was divided into a coil bobbin 48 and a core member 50, and only the coil bobbin 48 was made of fiber-reinforced plastic, but in the embodiment shown in FIGS. 5 and 6, the drive line wheel support The member 28 is of one-piece construction, and the driveline wheel support member 28 is constructed entirely of fiber reinforced plastic. As shown in FIGS. 5 and 6, when all parts of the drive line wheel support member 28 are integrally formed from fiber-reinforced plastic, the weight of the drive line wheel support member 28 can be further reduced. Can be done.

〔Effect of the invention〕

As explained above, according to the servo valve according to the present invention, the drive line wheel supporting member is integrally formed by embedding the drive line wheel inside fiber-reinforced plastic, making the movable part of the servo valve lightweight. In addition, the inductance of the drive line wheel can be reduced, and the efficiency and responsiveness of the force motor as the driving force generating section of the servo valve can be improved. Further, according to the present invention, since the drive line ring is embedded inside the fiber-reinforced plastic, the drive line ring is not damaged from the outside, and the gap in the magnetic path of the drive line ring is thereby reduced. As a result, the magnetic flux density of the drive line ring portion can be increased.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing the overall structure of a servo valve, Fig. 2 is a drawing showing the structure of a conventional servo valve, with an enlarged sectional view of the vicinity of the drive line wheel support member, and Fig. 3 is an embodiment according to the present invention. A drawing showing the structure of a servo valve.
FIGS. 4 to 6 are enlarged sectional views of the vicinity of the drive line wheel support member. FIGS. 4 to 6 are drawings showing the structure of other embodiments of the present invention, and each is an enlarged sectional view of the vicinity of the drive line wheel support member. 10...Force motor, 12...Valve part, 14
...Spool, 18...Valve body, 20a to e...
...Flow path, 28... Drive line wheel support member, 30... Drive line wheel, 32... Elastic body.

Claims (1)

[Claims] 1. A valve part consisting of a valve body in which a flow path is formed and a spool that is slidably disposed within the valve body and opens and closes the flow path, and an end of the drive line wheel support member is fixed to the spool of the valve part. At the same time, the drive line wheel support member is urged in one direction by an elastic body, and a drive line wheel is provided on the drive line wheel support member, and this drive line wheel portion is connected to a magnetic yoke and a pole. The spool and the drive line support member can be slid within the valve body against the biasing force of the elastic body by passing a current through the drive line. 1. A servo valve having a driving force generating section comprising a driving force generating section, wherein the drive line wheel support member is integrally formed by embedding the drive line wheel inside fiber-reinforced plastic.