JP2562497Y2 - Air micrometer air control valve - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air micrometer air control valve for automatically reducing the amount of air discharged from a measurement nozzle when measurement is not performed.

[0002]

2. Description of the Related Art A conventional air control valve for an air micrometer is shown in FIG.
No. 5-3369). That is, the air control valve 31
Comprises a first chamber 33 formed by the first diaphragm 32,
A second chamber formed by a second diaphragm having a smaller area than the first diaphragm;
The second diaphragms 32 and 33 are connected by a block 36. In addition, both the first chamber 33 and the second chamber 35 are provided with inflow passages 37 and 38 for pressurized air for measurement, respectively, and the second chamber 35 is communicated with a measurement nozzle of an air micrometer. An outflow channel 39 is provided. Second room 35
A flow regulator 41 supported by the block 36 for adjusting the amount of pressurized air flowing into the second chamber 35 by changing the opening degree of the communication port 40 is provided in the communication port 40 between the flow path and the inflow path 38. It is fitted. Further, the flow rate adjuster 41 (block 36)
The first and second diaphragms 32 and 34 are pressed toward the first chamber 33 by the spring 43 supported by the adjusting screw 42.

In the air control valve 31, the measurement adjuster 41 is operated by the balance between the force of the block 36 toward the second chamber and the force of the spring 43, and the measurement controller 41 connected to the outflow passage 40 is provided. When the nozzle is in the non-measurement state, the opening degree of the communication port 40 is reduced by the flow rate adjuster 41, thereby automatically reducing the amount of air discharged from the measurement nozzle.

[0004]

However, in such a conventional air control valve 31, the flow regulator is controlled by the balance between the force of the spring 43 adjusted by the adjusting screw 42 and the force generated in the block 36. Because of the structure for operating the air flow control valve 41, the operating characteristics of the flow regulator 41, that is, the air control valve 31 change due to the hysteresis of the spring 42. Also, the force of the spring 43 is
Since it is required that the spring 43 be kept constant irrespective of the operating position, the overall length of the spring 43 must be increased. For this reason, there were problems such as difficulty in downsizing the air control valve 31.

The present invention has been made in view of such conventional problems, and an object of the present invention is to provide an air control valve of an air micrometer that can ensure stable control operation and can be downsized.

[0006]

In order to solve the above-mentioned problems, according to the present invention, an inflow passage into which pressurized air for measurement flows, and a valve seat is formed in a communicating portion with the inflow passage. A back pressure chamber communicated with the measurement nozzle, a first diaphragm facing the valve seat and constituting the back pressure chamber, and a bypass flow path having a throttle communicating the inflow path and the back pressure chamber, A constant pressure chamber that maintains a constant internal pressure greater than the internal pressure of the back pressure chamber, and is disposed to face the first diaphragm and has a smaller area than the first diaphragm. A second diaphragm, and a core block connecting the second diaphragm and the first diaphragm. Further, it is preferable that the throttle provided in the bypass flow path is configured by a throttle valve.

[0007]

In the above construction, when the internal pressure of the back pressure chamber is lower than a predetermined pressure, the internal pressure of the constant pressure chamber is higher than the internal pressure of the back pressure chamber. And the second diaphragm bends toward the back pressure chamber. Accordingly, the first diaphragm sits on the adjacent valve seat and closes the inflow passage. Therefore,
The flow rate of the measurement pressurized air flowing into the back pressure chamber is a very small flow rate flowing through the bypass flow path having the throttle.

On the other hand, when the internal pressure of the back pressure chamber increases and becomes equal to or higher than the predetermined pressure, the first diaphragm and the second diaphragm have a difference in area between them and a difference between the back pressure chamber and the constant pressure chamber. It bends toward the constant pressure chamber due to the force generated by the pressure difference. Accordingly, the first diaphragm is separated from the valve seat, and the inflow path and the back pressure chamber communicate with each other.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. That is, as shown in FIG. 1, the air control valve 1 of the present invention comprises a first diaphragm 3 and a second block 4 for holding a first diaphragm 2, and a second diaphragm 5 between the second block 4. And a third block 6 which sandwiches the three-layer structure. A back pressure chamber 7 is separated from the first block 3 by the first diaphragm 2, and an inflow passage 8 for supplying pressurized air for measurement is connected to the back pressure chamber 7. Has been established. In the middle part of the back pressure chamber 7, a valve seat 10 facing a valve member 9 affixed to the first diaphragm 2 is formed in a communication part with the inflow passage 8.

The first block 3 includes a back pressure chamber 7.
And a bypass channel 11 that communicates with the inflow channel 8 is provided,
A throttle valve 12 is interposed in the bypass passage 11.
The throttle valve 12 has a hole 13 that penetrates the second block from the outer periphery of the third block 6 and communicates with the bypass flow passage 11, is screwed into the hole 13, and has a needle-shaped tip. And an adjustment knob 15 integrally formed. Further, in the first block 3,
An outflow passage 16 for communicating the back pressure chamber 7 with a measurement nozzle (not shown) of an air micrometer is formed.

On the other hand, in the second block 4, an intermediate chamber 17 communicating with the atmosphere is separated by the first and second diaphragms 2 and 5 facing each other, and the first and second diaphragms 2 and 5 are separated from each other. , 5 are connected by a core block 18. The third block 6 is provided with a constant pressure chamber 19 separated from the intermediate chamber 17 by the second diaphragm 5. The constant pressure chamber 19 has the outer dimensions of the back pressure chamber 7 formed in the first block 3.
, The second diaphragm 5 has a smaller area than the first diaphragm 2. The constant pressure chamber 19 communicates with a pilot-side inflow passage 20 that passes through the first and second blocks 3 and 4.

In the above configuration, the pressurized air for measurement is supplied to the inflow passage 8 and the pressurized air of a constant pressure is supplied to the pilot-side inflow passage 20 from the same air source as the pressurized air. When the gap between the measurement nozzle and the non-measurement surface changes when the measurement nozzle (not shown) of the air micrometer is connected to the outflow passage 16, the back pressure of the measurement nozzle, that is, the pressure in the back pressure chamber 7, changes. .

[0013] Figure 2 is a characteristic diagram of the air micrometer in such case, in FIG. 2, P ₀ is the constant pressure chamber 1
Pressure in 9 (a constant pressure), P ₁ is the pressure (back pressure of the measurement nozzle) in the back pressure chamber 7, Q ₀ is the total outflow, Q is runoff, curve B
Represents the change characteristic of P ₁ / P _{0 with} respect to the change of the ejection area A of the air at the measurement nozzle, and the curve C represents the change characteristic of Q / Q ₀ . The range between the points m and n on the curve B is the normal measurement range by the air micrometer, and the range of the corresponding outflow amount is between the points i and j on the curve C, respectively.
Thus, although the back pressure P ₁ does not use the measurement at lower than n points, outflow amount Q of the air at this time is large, so much larger than the measurement of air consumption. The point k on the curve B is P ₀ × S ₀ ≒ P ₁ × S where the area of the first diaphragm 2 is S ₀ and the area of the second diaphragm 5 smaller than this is S _1. and in that the _first relationship, q point on the curve C indicates the outflow of air supplied to the measuring nozzle through the back pressure chamber 7 from the bypass passage 11.

Therefore, the measurement nozzle is in a non-measurement state (the ejection area A is large) and the pressure P ₁ in the back pressure chamber 7 is not measured.
Is lower than the pressure corresponding to the point k on the curve B in FIG. 2, the relationship between the pressure P ₀ in the constant pressure chamber 19 and the pressure P ₁ in the back pressure chamber 7 is P ₀ > due to being P _1, more force F ₂ to the first back pressure chamber 7 direction occurs in the second diaphragm 5 than the force F ₁ to the constant pressure chamber 19 direction generated in the diaphragm 2 increases. Therefore, the first
And the second diaphragms 2 and 5 bend in the direction of the back pressure chamber 7 (the valve closing direction), and the valve member 9 of the first diaphragm 2
However, the inflow passage 8 is closed by sitting on the adjacent valve seat 10. Therefore, at the time of non-measurement, the amount of air ejected from the measurement nozzle has a very small flow rate corresponding to the point q on the curve C passing through the bypass channel 11.

On the other hand, when the measurement nozzle is in the measurement state (the ejection area A
Becomes smaller), the pressure P ₁ in the back pressure chamber 7 suddenly increases to exceed the pressure corresponding to the point k on the curve C and to the pressure corresponding to the point m, n between the measurement ranges. Become. For this reason,
Relationship between the area S ₁ of the first area S ₀ of the diaphragm 2 second diaphragm 5 is, S _0> due to an S _1, reversed the relationship between F ₁ and F ₂ as described above The first and second diaphragms 2 and 5 bend in the direction of the constant pressure chamber 19 (valve opening direction), the first diaphragm 2 is separated from the valve seat, and the inflow passage 8 and the back pressure chamber 7 communicate with each other ( 1). Therefore, at the time of measurement, air having an outflow amount according to the characteristic of the curve C is ejected from the measurement nozzle, and normal measurement can be performed.

Then, when the measurement nozzle returns to the non-measurement state and the pressure P ₁ in the back pressure chamber 7 falls below the pressure corresponding to the point k on the curve B, the first diaphragm 2 moves in the valve closing direction. Deflection closes the inflow path 8 again. Therefore,
It is possible to automatically reduce and control the amount of air ejected from the measurement nozzle during non-measurement.

As described above, in the air control valve 1, the operation of the first diaphragm 2 is controlled by a change in the balance between the back pressure chamber 7 and the constant pressure chamber 19 caused by a change in the pressure in the back pressure chamber 7, and Therefore, there is no hysteresis due to the structure of opening and closing the inflow passage 8. Therefore, when controlling the flow rate of the air discharged from the measurement nozzle, a stable control operation can always be obtained, and the response at the time of the control operation is good. Further, since the first diaphragm 2 can be operated with a simple structure without using a spring as in the conventional air control valve 31 shown in FIG. 3, the air control valve 1 can be manufactured easily and at low cost. It is possible to reduce the size. As a result, assembly to the air micrometer main body is also possible.

On the other hand, in the air control valve 1, when the opening of the throttle valve 12 is changed by the adjustment knob 15 shown in FIG. The flow rate of air constantly ejected from the nozzle changes. In other words, the point q shown in FIG. 2 can be moved in the horizontal axis direction to change the opening / closing timing of the control valve so as to correspond to the characteristics of the air micrometer.

In this embodiment, a separate valve member 9 is provided on the first diaphragm 2 to open and close the inflow hole 8 by the valve member 9, thereby improving the durability of the air control valve 1. The valve member 9 is shown in FIG.
Need not necessarily be provided.

[0020]

[Effect of the Invention] As described above, in the present invention,
The pressure balance between the back pressure chamber to which the measurement nozzle of the air micrometer communicates and the constant pressure chamber that maintains a predetermined internal pressure larger than the internal pressure of the pressure chamber of the nozzle is changed by the change in the internal pressure of the back pressure chamber. , Thereby controlling the operation of the first diaphragm forming the back pressure chamber connected by the core block and the second diaphragm forming the constant pressure chamber, and controlling the air in the measurement nozzle during non-measurement. The flow rate was automatically reduced.

For this reason, no hysteresis exists during the control operation due to the configuration, and the first and second diaphragms always have constant operating characteristics. Therefore, it is possible to provide an air control valve that ensures a stable control operation when controlling the flow rate of the air ejected from the measurement nozzle, and has good responsiveness during the control operation. In addition, the first and second diaphragms can be operated without using a spring, and the structure is simple, so that the air control valve can be easily reduced in size at low cost. As a result, it can be assembled to the air micrometer main body.

In the case where a throttle provided in a bypass flow path connecting the inflow path into which the pressurized air for measurement flows and the back pressure chamber is formed by a throttle valve, the throttle nozzle is constantly ejected from the measurement nozzle. The air flow is changed by the opening of the throttle valve. Therefore, the open / close timing of the control valve can be made to correspond to the characteristics of the air micrometer without being conscious of the operation characteristics of the air control valve itself.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an air control valve of an air micrometer according to an embodiment of the present invention.

FIG. 2 is a characteristic diagram of the air micrometer in the embodiment.

FIG. 3 is a diagram showing a conventional air control valve.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Air control valve 2 1st diaphragm 5 2nd diaphragm 7 Back pressure chamber 8 Inflow path 10 Valve seat 11 Bypass flow path 13 Throttle valve (throttle) 16 Outflow path 18 Core block 19 Constant pressure chamber

Claims (2)

(57) [Scope of request for utility model registration] 1. An inflow passage into which pressurized air for measurement flows,
A back pressure chamber having a valve seat formed in a communication portion with the inflow passage and communicating with the measurement nozzle; a first diaphragm facing the valve seat and constituting the back pressure chamber; A bypass passage having a throttle communicating with the back pressure chamber, and a constant pressure chamber configured to maintain a constant internal pressure larger than the internal pressure of the back pressure chamber, and disposed to face the first diaphragm. And a second diaphragm having an area smaller than that of the first diaphragm, and a core block connecting the second diaphragm and the first diaphragm. Meter air control valve. 2. The air control valve for an air micrometer according to claim 1, wherein the throttle provided in the bypass flow path is constituted by a throttle valve.