JP2624488B2 - Air relay - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an air relay that changes an extraction secondary pressure in response to a displacement of an external reciprocating input unit, and more particularly to an air relay having improved frequency response characteristics.

"Prior art and its problems" Referring to FIG. 4, an air relay to which the present invention is applied will be described first.

The housing 11 is denoted by reference numerals 11a, 11b,
It is composed of four members 11c and 11d. In the lowermost housing 11d, a primary pressure inlet 12 and a secondary pressure outlet 13 are opened, and a secondary pressure chamber communicating with the secondary pressure outlet 13 is provided.
14 are formed. A communication passage 16 between the primary pressure inlet 12 and the secondary pressure outlet 13 (secondary pressure chamber 14) is opened and closed by a main valve 17, and the main valve 17 is normally operated by the force of a compression spring 18. 17 closes the communication passage 16.

A control chamber 20 is formed between the uppermost housings 11a and 11b and communicates with the secondary pressure chamber 14 via a communication passage 19, and a measuring capsule 21 is located in the control chamber 20.
The measuring capsule 21 is a hollow container made of an elastic body, and its size is changed according to a pressure difference with the outside.

The measuring capsule 21 is moved up and down by external reciprocating input means.
The elevating shaft 22 is slidably held by a guide cylinder 23 fixed to the housing 11a. A pressing head 24 is fixed to a protruding portion of the upper end of the elevating shaft 22 from the guide cylinder 23, and a compression spring 26 is provided between the pressing head 24 and a fixing nut 25 on the guide cylinder 23 side. Inserted, elevating shaft
22, that is, the measuring capsule 21 is urged to move upward in the figure. The pressing head 24 is pressed by a peripheral cam 28 as external reciprocating input means, which is driven to rotate by a shaft 27, for example, and the measuring capsule 21
Moves up and down.

The pressing head 24 is screwed to the elevating shaft 22, and by adjusting the screwing position, the effective length of the elevating shaft 22 changes. That is, the vertical position of the measuring capsule 21 in the control room 20 when moved by the peripheral cam 28 is
It can be adjusted by the screwing position of the pressing head 24.
29 is a fixing screw for fixing the pressing head 24 to the elevating shaft 22 after the adjustment.

The measuring capsule 21 opens and closes the pilot valve 30 by the reciprocating movement (up and down movement) to move the floating piston 31 up and down.
To open and close between the primary pressure inlet 12 and the secondary pressure outlet 13.

That is, the pilot diaphragm is provided between the housings 11b and 11c and between the housings 11c and 11d, respectively.
33 and a peripheral edge of the controller diaphragm 34 are sandwiched therebetween, and a pilot pressure chamber 35 is formed by the housing 11b and the pilot diaphragm 33. A floating piston 31 is supported at the center of the pilot diaphragm 33 and the control diaphragm.

The upper end of the pilot valve 30 is a measuring capsule.
The valve portion of the lower surface is in contact with the lower surface of the pilot pressure chamber 35 via the communication passage 36 formed in the housing 11b. The pilot valve 30 has a ball body 37 at the upper end thereof.
7, i.e. the pilot valve 30 is always a measuring capsule 2
1 is pressed against the lower surface. The leaf spring 38 is fixed to the housing 11b by a fixing screw 39.

The pilot valve 30 changes the flow passage area of the communication passage 36, that is, the flow passage area between the control chamber 20 and the pilot pressure chamber 35, according to its vertical position. The pilot pressure chamber 35 communicates with the outside air through a bleed hole 40.

The floating piston 31 has a retainer plate 41 along the pilot diaphragm 33, a retainer plate 42 along the control diaphragm 34, a center block 43 sandwiched between both plates, and a balance weight 44. Shaft passage 45 open to pressure chamber 14
Is pierced. The shaft passage 45 communicates with a relief chamber 47 formed by the pilot diaphragm 33 and the control diaphragm 34 via a radial passage 46, and the relief chamber 47 further communicates with outside air via a relief hole 48. The opening end of the shaft passage 45 to the secondary pressure chamber 14 is opened and closed by a relief valve 49. The relief valve 49 is integrated with the main valve 17 by a connecting shaft.

The pressure receiving area of the pilot diaphragm 33 and the control diaphragm 34 is
Is set larger.

When the peripheral capsule 28 is rotated and the measuring capsule 21 is reciprocated, the air relay described above
Regardless of the magnitude of the primary pressure on the side, a secondary pressure that changes in magnitude according to the reciprocating motion of the measuring capsule 21 can be taken out to the secondary pressure outlet 13 side. Ie the main valve
Assume that the measuring capsule 21 is lowered by the peripheral cam 28 in a state where the communication path 16 is closed by the communication path 17. Then, the pilot valve 30 is lowered to open the communication passage 36. As a result, the pressure in the pilot pressure chamber 35 is increased, and the pilot diaphragm 33 and the floating piston 31 are lowered. The lowered floating piston 31 pushes the relief valve 49 by the end of the shaft passage 45, and lowers the main valve 17 integrated therewith to open the communication passage 16, so that the primary pressure introduction port is inserted into the secondary pressure chamber 14. A high pressure on the side 12 is introduced and is withdrawn from the secondary pressure outlet 13.

On the other hand, when the measuring capsule 21 rises,
Along with this, the pilot valve 30 rises and narrows the communication passage 36. Then, the introduction of the primary pressure air flowing into the pilot pressure chamber 35 is restricted. On the other hand, since the pilot pressure chamber 35 communicates with the atmosphere through the bleed hole 40, the internal pressure decreases. As a result, the floating piston 31 rises and the main valve 17
Rises accordingly and closes the communication passage 16. Therefore, the communication between the secondary pressure chamber 14 and the primary pressure introduction 12 is cut off, and the pressure in the secondary pressure chamber 14 decreases.

When the pressure in the secondary pressure chamber 14 fluctuates, the pressure in the control chamber 20 communicating with the secondary pressure chamber 14 via the communication passage 19 fluctuates, and the measuring capsule 21 itself expands / contracts due to this pressure fluctuation. . The same operation as described above occurs also by the expansion and contraction of the measuring capsule 21. Therefore, even if the primary pressure fluctuates, a constant secondary pressure can be taken out. Further, the vertical position of the measuring capsule 21 in the control chamber 20 can be adjusted by changing the screwing position of the pressing head 24 to the elevating shaft 22. Therefore, the bias pressure at which the main valve 17 starts to open the communication passage 16 can be adjusted.

However, in this precision air relay, the peripheral cam 28
When the rotation speed of the lifting shaft 22 rises, that is, the lifting frequency of the measuring capsule 21 increases, the secondary pressure outlet 13
It has been found that there is a problem that the secondary pressure taken out of the measuring capsule 21 is not synchronized with the elevation of the measuring capsule 21. In other words, the frequency response characteristic when trying to take out the pressure that fluctuates to the secondary pressure outlet 13 in response to the vertical movement of the measuring capsule 21 is poor.

FIG. 5 is a graph for explaining this problem. When the reciprocating cycle of the measuring capsule 21 is long (frequency is low), the secondary pressure taken out to the secondary pressure outlet 13 follows this. However, when the reciprocating cycle is short (frequency is high), the secondary pressure does not follow this.

"Object of the Invention" An object of the present invention is to obtain an air relay having good frequency response characteristics based on the discovery of such a problem with a conventional product.

`` Summary of the Invention '' The present invention, as a result of research on the problems of the above-mentioned conventional air relay, shows that the frequency characteristics are poor, when the measuring capsule 21 rises, the discharge of air in the pilot pressure chamber 35 is slow, It was concluded that this was because the ascending speed of the floating piston 31 was reduced, and this was improved and completed.

That is, the present invention provides a primary pressure inlet; a secondary pressure outlet; a main valve for opening and closing between the primary pressure inlet and the secondary pressure outlet; and a pressure difference between the secondary pressure outlet and the pilot pressure chamber. A floating piston that moves and opens and closes a main valve; a pilot valve that changes a communication area between a pilot pressure chamber and a secondary pressure outlet; a pressure regulating mechanism that reciprocates the pilot valve by external reciprocal input means In the air relay provided with, an air release valve is provided in the pilot pressure chamber, and further, when the air release valve and the external reciprocating input means move in the direction in which the pilot valve closes, the air release valve is provided. When moving in the opening and opening directions, they are interlocked by an interlocking opening / closing mechanism that closes.

Briefly speaking according to the above conventional example, the pilot pressure chamber 35
An air release valve is provided to release the air to the atmosphere, and this air release valve is interlocked with the measuring capsule 21 so as to be closed in the lowering step of the measuring capsule 21 and opened in the ascending step.

The pilot pressure chamber 35 communicates with the atmosphere through the bleed hole 40, but the effect of restricting the flow path by the bleed hole 40 is required only when the measuring capsule 21 is lowered, and is not required when the measuring capsule 21 is raised. Therefore, the pilot pressure chamber
Even if the air release valve is provided in 35, no inconvenience occurs.

"Examples of the Invention" The present invention will be described below with reference to illustrated examples. 1 to 3 show an embodiment of an air relay according to the present invention. FIG. 1 differs from the conventional apparatus of FIG. 4 only in the part of the atmosphere release valve 50, and is otherwise the same as FIG. The leaf spring 38 is shown by a chain line in FIG.

The atmosphere release valve 50 is provided on the housing 11b.
The housing 11b is provided with an axial passage 51 penetrating the control chamber 20 and the pilot pressure chamber 35, and a radial passage 52 communicating with the axial passage 51 and opening to the atmosphere. Has been inserted. The lower end of the valve shaft 53 is a valve portion 54 that opens and closes the open end of the axial passage 51.
The open end of the axial passage 51 is normally closed by a leaf spring 55 that urges the valve shaft 53 to move. The valve shaft 53 is provided with a radial passage 52.
Above, it is in sliding contact with an O-ring 56 fitted in the axial passage 51, thereby blocking communication between the control chamber 20 and the pilot pressure chamber 35. A small-diameter portion is provided at the end of the valve shaft 53 projecting into the control chamber 20.
57 and a retaining head 58 are formed.

On the other hand, an interlocking lever 60 is
Is pivoted. The inner end of the interlocking lever 60 is coupled to the lower surface of the measuring capsule 21 so as to be movable a small distance in the lateral direction, and the outer end has a forked portion 61 that engages with the small diameter portion 57 of the valve shaft 53. Is formed. The forked portion 61 moves without engaging with the small diameter portion 57, but engages with the step portion 62 or the retaining head 58 at both ends of the small diameter portion 57. The bifurcated portion 61 is located near the step 62 at the neutral position of the measuring capsule 21.

The other parts are the same as the conventional example shown in FIG.
The same portions are denoted by the same reference numerals and description thereof will be omitted.

The air relay having the above configuration is provided with a measuring capsule 21.
At the time of lowering, the device operates in the same manner as the conventional device. That is, when the measuring capsule 21 is lowered from the neutral position, the pilot valve 30 opens the communication passage 36, and as a result, the pilot pressure chamber
The pressure in 35 rises, and the pilot diaphragm 33 and the floating piston 30 fall. Descending floating piston 31
Presses the relief valve 49 by the end of the shaft passage 45, lowers the main valve 17 integrated therewith, opens the communication passage 16, and introduces the high pressure of the primary pressure introduction port 12 side to the secondary pressure chamber 14. I do.

When the measuring capsule 21 is lowered, the
The shaft 60 swings about the shaft 59, and the forked portion 61 moves upward.
However, the forked portion 61 only moves on the small diameter portion 57 of the valve shaft 53, and the valve shaft 53 does not move. That is, the atmosphere release valve 50 remains closed.

On the other hand, when the measuring capsule 21 rises from the neutral position, the interlocking lever 60 swings in a direction opposite to that in the downward movement. Then, the forked portion 61 of the interlocking lever 60 comes into contact with the step portion 62 to push down the valve shaft 53 against the leaf spring 55. Therefore the valve part 54
Is separated from the open end of the axial passage 51 and the pilot pressure chamber 35
Communicates with the atmosphere, and the pressure in the pilot pressure chamber 35 drops rapidly. As a result, the floating piston 31 rises, and the main valve 17 rises accordingly, closing the communication passage 16. Therefore, the communication between the secondary pressure chamber 14 and the primary pressure inlet 12 is cut off,
The pressure in the secondary pressure chamber 14 decreases.

In the above-described rising process of the measuring capsule 21, since the air release valve 50 is opened and the air in the pilot pressure chamber 35 is rapidly discharged, the rising speed of the floating piston 31 is reduced by the remaining air pressure in the pilot pressure chamber 35. Never do. In other words, the control chamber 20 (secondary pressure chamber 14) and the pilot pressure chamber
The pressure difference between 35 becomes larger than in the conventional device, so that the floating piston 31 rises instantaneously. Therefore, even if the elevating cycle of the measuring capsule 21 is shortened, the secondary pressure taken out to the secondary pressure outlet 13 sufficiently follows this.

In the above-described embodiment, the peripheral cam 28 is exemplified as the external reciprocating input means, in order to facilitate the description of the frequency response. In practice, however, a control device is provided which includes, for example, an operating device that operates by pressure from the secondary pressure outlet 12, and a detector that detects a certain displacement caused by the operating device, and outputs an output of the detector to the operating device. It is common in systems to use the detector as an external reciprocal input means. The present invention does not ask about the external reciprocating input means.

[Effects of the Invention] As described above, when the pilot valve moves in the closing direction by the external reciprocating input means, the air release valve is opened to release the pressure in the pilot pressure chamber. Even when the input frequency of the secondary pressure increases, the secondary pressure taken out from the secondary pressure outlet can follow the frequency, and the frequency characteristics can be improved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of the air relay of the present invention,
2 is an enlarged sectional view of a part II in FIG. 1, FIG. 3 is a perspective view of a main part in FIG. 2, FIG. 4 is a sectional view of a conventional air relay, and FIG.
FIG. 2 is a graph showing an example of a frequency response characteristic of a conventional air relay. 11 ... housing, 12 ... primary pressure inlet, 13 ... secondary pressure outlet, 14 ... secondary pressure chamber, 16 ... communicating passage, 17 ...
Main valve, 18 compression spring, 19 communication passage, 20 control room,
21 ... measuring capsule, 22 ... elevating shaft, 23 ... guide cylinder, 24 ... pressing head, 26 ... peripheral cam, 30 ... pilot valve, 31 ... floating piston, 33 ... pilot diaphragm, 34 ... Control diaphragm, 35 ... Pilot pressure chamber, 36 ... Communication passage, 40 ... Bleed hole, 47 ...
Relief chamber, 49 …… Relief valve, 50 …… Air release valve, 51
... axial passage, 52 ... radial passage, 53 ... valve shaft, 54 ...
... Valve part, 55 ... Leaf spring, 57 ... Small diameter part, 58 ... Retaining head, 59 ... Shaft, 60 ... Interlocking lever, 61 ... Bifurcated part, 62
…… the step.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Juichi Aoki 1-840 Mitsuhashi, Omiya City, Saitama Prefecture Fujikura Rubber Industries Co., Ltd. Omiya Plant (72) Inventor Mitsuru Hoshi 1-840 Mitsuhashi Omiya City, Saitama Prefecture Fujikura Rubber Industries (72) Inventor Takashi Ejiri 3-13-16 Nakano, Nakano-ku, Tokyo (56) References Japanese Utility Model Sho 62-112714 (JP, U) Japanese Utility Model Sho 56-35966 (JP, U) 62-126680 (JP, U)

Claims (1)

(57) [Claims] A primary pressure inlet; a secondary pressure outlet; a main valve for opening and closing the primary pressure inlet and the secondary pressure outlet; a pressure difference between the secondary pressure outlet and a pilot pressure chamber. A floating piston which moves in accordance with the above and opens and closes the main valve; a pilot valve which changes a communication area between the pilot pressure chamber and a secondary pressure outlet; and reciprocally operates the pilot valve by external reciprocating input means. An air release valve provided in the pilot pressure chamber, further comprising an air release valve and external reciprocating input means,
An air relay, wherein the external reciprocating input means opens the air release valve when moving the pilot valve in the closing direction and closes the air release valve when moving the pilot valve in the opening direction.