JP3106438B2 - Electric / pneumatic converter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric / pneumatic converter for converting an electric signal into a pneumatic signal corresponding to an electric signal in a state in which a supply air pressure is applied, and in particular, fixing a coil spring so as to secure a stable output. The present invention relates to an electric / pneumatic converter having an improved structure.

[0002]

2. Description of the Related Art The structure shown in FIG. 3 is employed as a conventional structure for fine positioning of a nozzle / flapper mechanism.
Reference numeral 10 denotes a flapper.
Are fixed to the support portion 12 via a leaf spring 11.

A driving force F corresponding to the electric signal Id is applied to one surface of the flapper 10 by, for example, a torque motor 13 to which an electric signal Id is applied, so that the flapper 10 can be displaced.

A nozzle 14 is provided on the opposite side of the flapper 10.
Are arranged facing each other while maintaining a small gap L. The supply pressure Ps is applied to the nozzle 14 through the throttle 15, and a nozzle back pressure Pb corresponding to the gap L is taken out.

On the other hand, on the other end 10B of the flapper 10, hooks 16B and 17B, which are the other ends of the coil springs 16 and 17 each having a pair of one ends 16A and 17A fixed to a case or the like, are screwed. Are fixed together. These coil springs 16 and 17 are for adjusting the operation position of the nozzle back pressure Pb.

FIG. 4 is an exploded view showing details of a fixing structure for fixing the coil springs 16 and 17 to the hook 10B of the flapper 10. A washer 19 is interposed between the hooks 16B, 17B of the coil springs 16, 17, and these hooks 16B, washer 19, and hook 1 are provided.
7B is a flapper 1 with a screw 18 through a washer 20.
The hook 10B is fixed to a screw hole 10C formed in the hook 10B.

The operation of the electric / pneumatic converter constructed as described above is as follows. When the electric signal Id is applied to, for example, the torque motor 13, a driving force F corresponding to the electric signal Id is applied to the flapper 10.

As a result, the flapper 10 changes the gap L with the nozzle 14 with the one end 10A as a fulcrum, and the nozzle back pressure Pb changes accordingly. The reference operating point in this case is determined by the coil springs 16 and 17. As described above, the electric signal for obtaining the nozzle back pressure Pb, which is the air pressure signal corresponding to the electric signal Id,
It constitutes a pneumatic converter.

[0009]

However, the conventional electric / pneumatic converter described above has the following problems.

This will be described with reference to FIG. FIG. 5 is an explanatory diagram for explaining the drawbacks of the conventional electric / pneumatic converter. Even a slight displacement of the hooks 16B and 17B of the coil springs 16 and 17 greatly affects the change of the nozzle back pressure Pb and causes a change in the air pressure signal. Then, hook 16B, 17B
It is necessary to prevent the displacement by fixing each of the coil springs 16 and 17 with the screw 18 in a state where the coil springs 16 and 17 are pulled upward or downward with a constant force f in consideration of the fact that the coil spring 18 is larger than the screw 18.

Since the hooks 16B and 17B are twisted in the rotation direction when screwing, the coil spring 1
It is difficult to fix 6, 17 in a predetermined direction. further,
If the washer 19 is not interposed between the hooks 16B and 17B, the hooks 16B and 17B will be in direct line contact with each other directly, causing a positional shift, and the fixing will be unstable due to variations in the shape of the hooks.

[0012]

In order to achieve this object, the present invention provides an electric / pneumatic converter for converting an electric signal into a pneumatic signal corresponding to an electric signal in a state where a supply pressure is applied. A flapper whose other end is displaced in response to the electric signal, and a nozzle back disposed opposite to the flapper and corresponding to a gap generated between the flapper and the flapper due to the supply pressure being applied through a throttle and being displaced. A nozzle for extracting pressure, at least one coil spring having one end formed in a hook shape and the other end fixed, a metal plate formed of a material softer than the coil spring,
The hook-shaped part itself is directly pressed onto one surface of the metal plate.
This hook-shaped part is pressed at least
Turn the metal plate to a depth of at least half the diameter of the ring.
Comprising a coupling means which is write bond, in which the metal plate is the electro / pneumatic converter, characterized in that fixed to the other end of the flapper.

[0013]

[Operation] The flapper has one end fixed and the other end displaced in response to an input electric signal. The nozzle is disposed to face the flapper, and the supply pressure is applied through a throttle to take out the nozzle back pressure corresponding to the gap generated between the nozzle and the flapper due to the previous displacement.

In this case, a metal plate connected to a coil spring is fixed to the other end of the flapper. This metal plate is formed of a material softer than the coil spring. The hook-shaped part itself is pressed directly on one side of the plate , and at least the hook-shaped part is
Also metal to a depth of more than half the diameter of the coil spring
It is embedded in the board and joined. Since such a coupling method is employed, the flapper can be stably positioned with a small number of components.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a partial perspective view showing a main part of the present invention.
Parts having the same functions as those of the conventional electric / pneumatic converter shown in FIG. 3 and FIG.

A screw hole 21 is formed in the end 10B of the flapper 10.
Are formed. On the other hand, a rectangular metal plate 22 is fixed to the screw hole 21 using the screw 18. Metal plate 22
It is fixed a pair of coil springs 23, 24 the tip portion is formed as a hook 23B, 24B is sinking in. A screw 18 is provided at the center of the metal plate 22.
Is inserted in the through hole 25.

The screw 18 is screwed into the screw hole 21 formed at the end 10 of the flapper 10 through the through hole 25 to fix the metal plate 22. The other points are almost the same as the configuration shown in FIG. The connection between the metal plate 22 and the coil springs 23 and 24 will be further described with reference to the explanatory view shown in FIG.

FIG. 2A is a plan view, and FIG. 2B is a side view. The metal plate 22 is made of a material softer than the coil springs 23 and 24, for example, brass, copper, aluminum or the like. Therefore, the hooks 23B and 24B are
2 and pressed against the metal plate 22 from above in a direction indicated by an arrow P with an avar press or the like.
Directly molded into the metal plate 22 hooks 23B, 24B of the shape by making sink into in.

When the coil springs 23 and 24 are sunk into the metal plate 22 by the above-described molding, the coil springs 23 and 24 are pressed onto the metal plate 22 in the form of the individual hooks 23B and 24B themselves, and the coil springs are displaced due to variations in parts. 23, 24 hooks 23B, 24B and metal
The gap generated between the groove of the plate 22 and the groove of the plate 22 can be avoided.

Since the insides of the hooks 23B and 24B enclose the metal plate 22, the coil springs 23
No displacement occurs even if a tensile force acts in the direction of arrow fA on 24.

Coil springs 23 and 24 and metal plate 22
At the time of joining with the coil spring 2, for example, when heating is required, such as welding, the coil spring 2
Although the spring constants 3 and 24 change, such a concern is unnecessary according to the molding shown in FIG.

In the case of miniaturization, the size of the metal plate 22 itself is limited. However, even in such a case, according to the forming shown in FIG. It can be used in a small space without requiring extra space.

The pressure-bonding portion may be fixed with a fixing material such as an adhesive if necessary. Further, the shape of the hook is not limited to the ring shape, but may be any shape such as an L-shape as long as it can wrap the metal plate 22.

[0024]

Effect of the Invention] As has been specifically described with examples, according to the present invention, the coil to the metal plate by the individual fluoride <br/> click itself of the coil spring to press directly on the metal plate Since the spring is inserted into the structure and fixed to the flapper, no gap is formed between the coil spring hook and the metal plate.Therefore, there is no displacement of the flapper in use and stable positioning of the flapper. It becomes possible. That is, individual variations in hook shape
An electric / pneumatic converter which is not affected by the above is obtained. Further, in the past, there was a gap between the coil spring and the screw for mounting, so that it was pulled and fixed at the time of mounting. . Further, according to the present invention, the number of components can be reduced as compared with the related art, which contributes to cost reduction.

[Brief description of the drawings]

FIG. 1 is a main part configuration diagram showing a main part configuration of one embodiment of the present invention.

FIG. 2 is an explanatory diagram specifically explaining a main part configuration shown in FIG. 1;

FIG. 3 is a configuration diagram showing a configuration of a conventional electric / pneumatic converter.

FIG. 4 is an exploded view for explaining an assembling order of the electric / pneumatic converter shown in FIG.

FIG. 5 is an explanatory diagram for explaining a problem of the electric / pneumatic converter shown in FIG. 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Flapper 13 Torque motor 14 Nozzle 15 Restrictor 16, 17, 23, 24 Coil spring 16B, 17B, 23B, 24B Hook 22 Metal plate

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takeshi Nishijima 2-9-132 Nakamachi, Musashino-shi, Tokyo Inside Yokogawa Electric Corporation (72) Inventor Ryusaku Kubota 2-9-132 Nakamachi, Musashino-shi, Tokyo Inside Yokogawa Electric Corporation (72) Inventor Minoru Midorikawa 2-9-132 Nakamachi, Musashino City, Tokyo Yokogawa Electric Corporation (72) Inventor Yasuo Kasahara 2-9-132 Nakamachi, Musashino City, Tokyo Yokogawa Inside Electric Co., Ltd. (72) Inventor Akira Inoue 2-9-32 Nakamachi, Musashino-shi, Tokyo Examiner, Yokogawa Electric Co., Ltd. Kento Sato (56) References JP-A-55-47002 (JP, A) Sho-62-28118 (JP, U) Jiko 38-25711 (JP, Y1) (58) Fields investigated (Int. Cl. ⁷ , DB name) F15B 5/00

Claims (1)

(57) [Claims] 1. An electric / pneumatic converter for converting a pneumatic signal corresponding to an electric signal in a state where a supply pressure is applied, comprising: a flapper having one end fixed and the other end displaced corresponding to the electric signal; A nozzle arranged opposite to the flapper to take out a nozzle back pressure corresponding to a gap generated between the flapper and the supply pressure applied through the throttle when the supply pressure is applied through the throttle; At least one fixed coil spring, a metal plate formed of a material softer than the coil spring, and the hook-shaped portion itself directly pressed against one surface of the metal plate.
This hook-shaped part is pressed at least
Turn the metal plate to a depth of at least half the diameter of the ring.
Inclusive bound are provided with coupling means, said metal plate electrical / pneumatic converter, characterized in that fixed to the other end of the flapper.