JP3504941B2 - Switching valve - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention can be used in a switching valve, and more particularly in an air leak detection device capable of performing accurate and stable air leak detection without being affected by fluctuations in the measurement environment or operating environment. The present invention relates to a switching valve that can realize detection.

[0002]

2. Description of the Related Art Conventionally, a container which is hermetically sealed while leaving an empty chamber inside has been used in various industrial fields. For example, in a sealed relay which is a microelectronic component, a movable contact and an exciting coil are housed in a plastic container, and a sealed small small power relay element can be obtained by sealing the container. In such a sealed relay, the air or inert gas sealed in the container keeps the moving parts of the relay and other internal parts stable.
Since the internal parts are not affected by dust or the like, it is possible to maintain stable operation characteristics of the microelectronic parts for a long period of time. Of course, the hermetically-sealed container is applicable not only to the above-mentioned microelectronic parts but also to a wide range of fields such as medical use, food, and the like, and similarly, the object in the hermetically-sealed container can be stabilized and protected.

Such a hermetically sealed container may not be able to maintain a perfect hermetically sealed state due to defective sealing during manufacture, damage to the container itself, or the presence of through holes or the like. The hermetically sealed container in which the hermetically sealed state has been impaired must be reliably removed as a defective product due to air leak. Several air leak detection methods have been proposed to make this determination.

Previously, heating or depressurization was performed while the hermetically sealed container was immersed in a CFC liquid or the like, and at this time, the presence or absence of a leak was determined by detecting bubbles generated in the CFC liquid, but from the viewpoint of environmental protection. Nowadays, the use of CFC liquid is banned, and air leak detection by other methods is desired. For example, in a detection method called a differential pressure method, two sealed tanks connected with a pressure balance detector sandwiched therebetween are prepared, a sealed container to be measured is stored in one sealed tank, and an air leak occurs in the other sealed tank. Store a standard airtight container that does not exist. In this state, the closed tanks are depressurized or pressurized to form the same constant pressure space. If there is a leak in the measured closed container, the internal space of the measured closed container becomes the same as the internal space of the closed container, and the pressure balance between the two closed containers is lost. By detecting this collapse, the presence / absence of a leak can be determined.

However, in this differential pressure type device,
There is a problem that a sufficient equilibration time is required to stabilize the pressure in the closed tank, and the inspection time cannot be shortened. Further, in order to stabilize the internal pressure of the closed tank,
There is a drawback that a sufficiently large pressure source or pressure reduction source is required, the apparatus becomes large, and a large amount of energy is required only for leak inspection. In addition, for imperfect leaks in which air pressure leaks gradually after the pressure in the sealed tank stabilizes, so-called small leaks and so-called medium leaks, it is possible to detect pressure balance disruptions, but complete leaks (large leaks due to large holes, etc. (Leak) is present,
At the start of pressurization or depressurization, the internal space of the sealed container to be measured has already become the same as the internal space of the closed tank, so there is a possibility that a complete leak cannot be accurately detected.

Therefore, the present applicant has proposed an air leak detection method called a direct pressure type. The air leak detection device using this direct pressure system is a closed tank capable of forming a closed space of a predetermined volume capable of housing a closed container which is the object to be measured, and a measurement tank having a predetermined initial tank pressure, A reference pressure chamber having a reference volume capable of forming a reference pressure state different from the initial tank pressure, a communication switching mechanism that allows selective communication between the measurement tank and the reference pressure chamber, and pressure in the measurement tank And a determination unit that determines the presence or absence of an air leak in the closed container based on the pressure change in the pressure inside the measurement tank that has changed due to the communication between the measurement tank and the reference pressure chamber.

According to the air leak detection device having such a structure, when an air leak exists in the closed container, the internal space of the closed container is assimilated with the internal space of the measuring tank, and the substantial internal volume increases. The pressure reached by the measuring tank after communication between the measuring tank and the reference pressure chamber rises (when the reference pressure chamber is depressurized with respect to the measuring tank) or decreases (when the reference pressure chamber is set to the measuring tank) (When pressed against). The presence or absence of air leak is determined based on this pressure change. At this time, since it is not necessary to stabilize the pressure in the measurement tank for the preparation for measurement, it is possible to perform a quick determination with an easy configuration that connects the measurement tank and the reference pressure chamber.

[0008]

In the above-described direct pressure type air leak detection device, since the determination is made based on the slightest pressure change, the volume between the measurement tank and the reference pressure chamber, that is, the measurement-related space The volume is preferably as small as possible with respect to the volume of the internal space of the closed container. However, in general, since the air tube is used to connect the measurement tank and the reference pressure chamber, or the reference pressure chamber itself is composed of an air tube, the volume cannot be sufficiently reduced under the present circumstances. is there. It is also possible to form an air passage in a block-shaped casing instead of the air tube, but considering the connection with the switching valve, the shape of the passage becomes complicated, hindering the reduction of volume and air leakage. It is necessary to sufficiently take measures (for example, use of a blind cover or the like due to the perforation of the passage), which complicates processing and increases the size of the block, that is, increases the size of the device.

By the way, a switching valve is used as a communication switching mechanism for communicating between the measuring tank and the reference pressure chamber as described above. It is not preferable to use it because it induces air pressure fluctuations. Furthermore, when a switching valve other than a solenoid valve, such as an air switching valve, is usually used, the switching valve includes a sliding portion for performing a switching operation. as a result,
Heat may be generated due to the sliding, or the sliding portion, especially the O-ring for air sealing may be worn. As a result, there are problems that pressure fluctuations occur and air leakage is induced due to defective opening / closing operation of the switching valve, leading to a decrease in measurement accuracy.

The present invention has been made in view of the above problems of the prior art, and an object thereof is to provide stable pressure measurement in a direct pressure type air leak detection device, which is excellent in durability, and has another valve operation. It is to provide a switching valve that does not affect the operation of the configuration.

[0011]

In order to achieve the above-mentioned object, the present invention is a switching valve having a first port and a second port, which are in communication with each other. A two-port connecting portion surrounds the drive rod having a first elastic member that is connected to and detached from the first port and switches between communication and non-communication between the first port and the second port, and the connection portion between the first port and the second port. And the surface on which the connection is formed and the front
Elastic part that adheres closely to the surface of the drive lot facing the connection part
A timber, blocking Then co the connecting portion relative to the outside air
The compression deformation allows the stroke of the drive rod in the contacting and separating direction of the first elastic member and the compression deformation.
And a second elastic member which is arranged in a non-sliding position with the inner wall surface of the switching valve in shaping .

In order to achieve the above object, in the above structure, the second elastic member is formed by laminating one or a plurality of O-rings.

Further, in order to achieve the above-mentioned object, the present invention is a switching valve having a first port and a second port which are internally communicated with each other, wherein the first port and the second port are connected. Part, a valve base having a first annular protrusion that surrounds the first port, and a second annular protrusion that has a higher protrusion height than the first annular protrusion that surrounds the first annular protrusion and the second port. And, while always contacting the second annular projection and blocking the connection portion between the first port and the second port from the outside air, and selectively contacting the first annular projection, establishing communication between the first port and the second port. A drive rod having an elastic member that switches between non-communication.

According to this structure, since the drive rod does not include the sliding member in the seal portion, it has excellent durability and the operation of the switching valve does not affect other operations.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention (hereinafter referred to as an embodiment) will be described below with reference to the drawings.

FIG. 1 is a schematic explanatory view illustrating the basic configuration concept of an air leak detection device 10 which can use the switching valve of the present embodiment. The air leak detection device 10 stores a sealed container to be measured, for example, a seal relay (hereinafter, referred to as a work) 12 that is a microelectronic component, and a measurement tank 14 for performing inspection.
A pressure reducing device 16 (pressure device) connected to the measurement tank 14 as a communication switching mechanism via a plurality of switching valves (four switching valves Va, Vb, Vc, Vd in the present embodiment); A pressure sensor 18, which is arranged in the vicinity of the tank 14 and is capable of detecting the pressure inside the tank (actually, the flow path connected to the measuring tank 14) inside the measuring tank 14, the pressure reducing device 16, the pressure sensor 18,
The control unit 20 includes a control unit 20 including a determination unit that controls the switching valves Va, Vb, Vc, Vd, etc., and performs a calculation regarding a detected value and outputs a predetermined determination.

The measuring tank 14 includes, for example, an upper casing 14a (second type) and a lower casing 14b connected by a hinge or the like.
In the openable and closable case configured by the (first type), the measurement chamber 22 (measurement space) for accommodating the work 12 is formed in the substantially central portion in a state where the upper casing 14a and the lower casing 14b are joined (closed state). Form. An O-ring 24, for example, is arranged around the measurement chamber 22 as an airtight seal member in order to ensure the airtightness of the measurement chamber 22 in the closed state. Therefore, the upper casing 14a and the lower casing 14b can form the measurement chamber 22 having a substantially enclosed space of a predetermined volume. The measurement chamber 22 has an upper housing 14a so that the inner wall surface is not deformed due to pressure change or the like.
The entire lower housing 14b or the inner wall surface is formed of metal, hard resin, or the like.

On the other hand, the decompression device 16 is a vacuum pump 1.
6a and a decompression tank 16c having a regulator 16b, so that the decompression tank 16c can always maintain a predetermined pressure. In addition, the switching valves Va, Vb, Vd
Is the flow path 2 that connects the measurement tank 14 and the decompression device 16 in communication.
6 is opened and closed selectively. In particular, the space formed between the switching valve Va and the switching valve Vb defines a reference pressure chamber (reference pressure space) 28 capable of forming different pressure states with respect to the measurement tank 14. Further, the switching valve Vc is a valve for opening to the atmosphere, and is used for the flow path 26 and the measurement chamber 2 of the measurement tank 14.
It is opened when the pressure of 2 is released to the atmosphere.

In the above structure, the pressure inside the measurement chamber 22 is changed by selectively connecting the measurement chamber 22 and the reference pressure chamber 28 having a different internal pressure to each other. The presence or absence of air leak of the work 12 housed in the measurement chamber 22 is determined according to the pressure change state. That is, the internal space 12a of the work 12 becomes independent or the same as the residual space 22a of the measurement chamber 22 (the internal space of the measurement tank 14 excluding the volume of the work 12) due to the complete or incomplete sealing of the work 12. As a result, measurement room 2
The substantial residual space (remaining volume) of 2 fluctuates, and the measurement chamber 22
The ultimate pressure when communicating with the reference pressure chamber 28 fluctuates. The presence / absence of air leak is determined based on this variation. In addition,
In FIG. 1, when the work 12 is arranged in the measurement chamber 22, the residual space 22a of the measurement chamber 22 is illustrated to be relatively large, but in reality, the volume of the measurement chamber 22 is slightly larger than the volume of the work 12. Then, the internal space 12 of the work 12
The amount of variation in the space inside the measurement chamber 22 due to the assimilation of a appears significantly. For example, when the internal space 12a of the work 12 is 0.1 cc, the remaining space 22 of the measurement chamber 22
a is set to 1.5 cc, and the capacity of the reference pressure chamber 28 at this time is set to 0.8 cc, for example.

An operation table table of the switching valves Va, Vb, Vc, Vd shown in FIG. 2 and the measuring chamber 22 of the measuring tank 14 shown in FIG.
The operation of the air leak detection device 10 of FIG. 1 will be described with reference to the pressure change diagram of FIG. In this embodiment, the atmospheric pressure is constant.

First, as a preparation for the determination, the workpiece 12 to be determined is put into the measuring chamber 22 of the measuring tank 14. At this time, the control unit 20 opens only the switching valves Va and Vb (timing T
1). Therefore, the measurement tank 14 and the reference pressure chamber 28 defined by the switching valves Va and Vb communicate with each other. Subsequently, the upper casing 14a and the lower casing 14b of the measuring tank 14 are brought into close contact with each other (lid closing operation), and the measuring tank 14 is put into a substantially sealed state. Since the internal pressure of the space including the measurement chamber 22 increases due to this lid closing operation, the control unit 20 follows the switching valves Va and Vb.
The switching valve Vc is opened to bring the pressure in the measurement chamber 22 and the reference pressure chamber 28 to atmospheric pressure (P0 = 1013 × 10 ² Pa) (timing T2). Next, the switching valves Va and Vc are closed and the switching valve Vd is opened (timing T3). By this operation,
A space including the reference pressure chamber 28 is connected to the pressure reducing device 16,
It is controlled by the decompression device 16. At this time, in the decompression device 16, for example, PV = 0.4 kgf / cm ² (392 × 10
Reduce pressure to ² Pa). In this state, the switching valves Vb and Vd are closed. That is, all the switching valves are closed to form the reference pressure chamber 28 having a predetermined volume (0.8 cc) of the reference pressure state value P1 (a state in which the atmospheric pressure is reduced by 392 × 10 ² Pa), and the control unit 20 Complete preparation for measurement (timing T
4).

When a measurement start signal is given to the control unit 20, the control unit 20 opens only the switching valve Va (timing T5) to make the measurement tank 14 (measurement chamber 22) and the reference pressure chamber 28 communicate with each other and perform measurement. The internal pressure of the tank 14 (measurement chamber 22) is changed (decompressed).

The control unit 20 controls the pressure sensor 18 in a state where only the switching valve Va is opened, and the elapsed time B (0.3 seconds has elapsed after opening the switching valve Va) and the elapsed time C (switching valve Va The pressure (for example, PXa, PXb) in the measurement chamber 22 at the time point of 0.4 seconds after the opening) is measured (see FIG. 3). Subsequently, the control unit 20 opens the switching valves Va, Vb, Vd for a predetermined time (for example, elapsed time C-D; 0.4 seconds), and sets the measurement chamber 22 to the initial reference pressure state of the reference pressure chamber 28. The pressure is reduced to the value P1 (timing T6), the switching valve Va is closed (timing T6).
7) Then, after a lapse of a predetermined time (for example, 3 seconds), the pressure (for example, PXd) in the measurement chamber 22 is measured. At this time, when there is no air leak in the work 12, the measurement value of the pressure sensor 18 in the measurement chamber 22 becomes PXd = PV. Furthermore, the control unit 20
Is the measuring chamber 2 for a predetermined time (for example, 2 seconds) after the PXd measurement.
The pressure of 2 (for example, PXc) is measured, and the pressure measurement for air leak determination is completed.

Subsequently, the control unit 20 starts the air leak determination process. By the way, the following relationship is established between the measurement chamber 22 of the measurement tank 14 and the reference pressure chamber 28 according to Boyle-Charles' law.

[0025]

[Equation 1] At this time, since P1 = P0-PV and P2 = P0-PX, the formula 1 can be summarized as follows.

[Equation 2] Becomes It is assumed that the gas temperature changes when the measurement chamber 22 and the reference pressure chamber 28 are connected, but is stable and does not change after a predetermined time.

Therefore, the measuring chamber 2 measured at the elapsed time C
The pressure PX (PXa) of 2 and the reference pressure state value PV (PXd) of the reference pressure chamber 28 are the reference volume V1 of the reference pressure chamber and the measurement chamber 22 when the work 12 is stored in the reference volume V1.
Can be associated with a fixed value defined by the total volume plus the residual volume V2. When there is no air leak in the work 12, that is, when the work 12 is a "good product" that is completely sealed, the reference pressure state value PV of the reference pressure chamber
And the value defined by the in-tank pressure value PX (PXa) of the measurement chamber 22 measured after connecting the reference pressure chamber 28 and the measurement chamber 22 is the volume V1 of the measurement chamber 22 when there is no air leak. The volume V2 of the reference pressure chamber 28 is equal to the value defined by the volume. For example, V1 = 0.8cc, V2 =
In case of 1.5cc, the value of PX / PV is V1 / (V1 + V2)
= 0.8 / 2.3 = 0.3478. On the other hand, "completely leaked product (large leak)" in which the workpiece 12 completely leaked.
, V1 / (V1 + V2) = 0.8 / 2.4 =
It becomes 0.3333. Therefore, when a non-defective product having no air leak is stored, the fixed pressure V1 / (V1 + V2) defined by the volumes of the measurement chamber 22 and the reference pressure chamber 28 is used as the determination reference, and the corresponding reference pressure state value PV of the reference pressure chamber is set.
(PXd) and the chamber pressure value PX (PXa) of the measurement chamber 22 measured after communicating with the measurement chamber 22 are calculated to determine whether it is a “good product” or a “complete leak product”. You can In order to make a strict determination, it is preferable to use a value of V1 / (V1 + V2) = 0.3478 as the determination value, but in consideration of the measurement error, the determination value determined to be a good product is, for example, 0. If set to 3400, a practical large leak can be favorably determined. Since PV and PX are measured at substantially the same time, the atmospheric pressure at the time of measurement can be considered to be almost constant, so that the determination can be performed well.

In FIG. 3, a non-defective workpiece 12 is placed in the measuring chamber 22.
Workpiece 12 that completely causes air leak (large leak) when pressure is stored and measured (solid line A in the figure)
Shows a pressure change (broken line B in the figure) when the measurement is carried out by storing in the measurement chamber 22. From the figure, it can be seen that when a large leak occurs, the decompression rate decreases because the substantial volume in the measurement chamber 22 increases. In FIG. 3, the pressure is temporarily decreased between the elapsed times A and C, and then rises again. When the pressure of the air is rapidly reduced, the air is rapidly cooled, and at this time, the rapidly cooled air moves around. It takes heat and returns to room temperature (adiabatic expansion). This temperature change causes a pressure change. As a result, the temporary pressure drop as described above occurs. In the present embodiment, when a large leak occurs, the pressure inside the measurement chamber 22 is reduced to the initial pressure of the reference pressure chamber 28 after the elapsed time C, so that the pressure change is
It is the same as a good product.

As described above, the measurement chamber 22 and the reference pressure chamber 28
Fixed ratio defined by the volume of the measurement chamber 22 and the reference pressure chamber 2
It is defined by the internal pressure of the measurement chamber 22 measured after communicating with the measurement chamber 8 and the pressure inside the measurement chamber after a predetermined time elapses after the measurement pressure of the measurement chamber containing the sealed container to be measured is set to the reference pressure state value of the reference pressure chamber. By comparing with the fluctuation ratio, the presence / absence of a large leak can be determined quickly and accurately.

Subsequently, the control unit 20 detects the presence or absence of an incomplete leak, that is, a small leak in which the air in the work 12 leaks little by little. In the case of a small leak, since the leak amount is extremely small, the measurement chamber 22 and the reference pressure chamber 28 are connected to each other,
Even if the pressure in the measurement chamber 22 is changed, the pressure change immediately after the communication is the same as that of the non-defective product. Therefore, the control unit 20
At the timing T7, the switching valve Va is closed, and after a lapse of a predetermined time (for example, 3 seconds; elapsed time E), the measurement chamber 22 measured
Pressure (PXd) and a certain time (eg 2
Second: The pressure (PXc) of the measurement chamber 22 at the elapsed time F) is measured to measure the pressure change amount in the sealed measurement chamber 22 after a predetermined time. When a small leak occurs, the internal pressure of the measurement chamber 22 gradually increases due to the air leak, so the rate of change is different from that of a non-defective product (the pressure change during a small leak is indicated by three points in FIG. 3). (Shown by chain line C). By measuring the pressure change (flowering time EF) after a predetermined time after reducing the internal pressure of the measurement chamber 22 and comparing it with the pressure change in the case of a non-defective product, it is appropriate even when a small leak occurs. Leak determination can be performed. It should be noted that at the elapsed time C-F in FIG. 3, the pressure in the measurement chamber 22 once sharply drops and then gradually rises. This is also due to the adiabatic expansion described above, and even in the case of the good work 12, a slight pressure change occurs. When there is a small leak, the rate of change increases by the amount of air leak.

Furthermore, in the air leak of the work 12, there is a case where an air leak of a middle degree between the large leak and the small leak, that is, a so-called medium leak occurs. In this case, as indicated by the one-dot chain line D in FIG. 3, the medium leak is completed by, for example, the elapsed time DE in FIG. As a result, the elapsed time EF for determining a small leak
In the interval, only the pressure change due to adiabatic expansion, that is, the same pressure change as the non-defective product (solid line A in FIG. 3) is shown, and it becomes impossible to perform an appropriate leak determination. On the other hand, as shown in FIG. 3, since the values of PX / PV at the elapsed times C and E for determining a large leak both increase, V1 /
Judgment based on the fluctuation ratio (pressure ratio) with respect to the fixed ratio (volume ratio) defined by (V1 + V2) cannot be performed (may be judged as a good product). Therefore, in order to determine the medium leak, attention is paid to the pressure change immediately after the measurement chamber 22 and the reference pressure chamber 28 are communicated with each other (elapsed time BC; for example, 0.1 s). As shown in FIG. 3, when the medium leak occurs, the internal pressure of the measurement chamber 22 increases due to the air leak even during the elapsed time B-C as compared with the case of the non-defective product. The presence of the medium leak is determined by comparing the pressure change rate in this short time with the pressure change rate of the non-defective product.

As described above, the reference measurement chamber 28 having a predetermined reference volume and reference pressure state value is selectively connected to the measurement chamber 22 to observe the pressure change in the measurement chamber 22. , The control unit 20 has a large leak, a medium leak,
All air leaks such as small leaks can be discriminated and reliably determined, and the results are output, for example, as “good product”, “large leak”, “medium leak”, and “small leak”. At this time, since only the measurement chamber 22 and the reference pressure chamber 28 are connected to measure the pressure change, it is possible to quickly and accurately determine the presence or absence of complete leak and incomplete leak with an easy configuration.

In the above embodiment, an example in which the reference pressure chamber 28 is decompressed has been described, but the same determination can be made even if the reference pressure chamber 28 is pressurized and the tank pressure of the measurement chamber 22 is changed. It can be carried out. Although the measurement chamber 22 is set to the atmospheric pressure, if the pressure state is different from that of the reference pressure chamber 28, the same effect as that of the present embodiment can be obtained in the depressurized state or the pressurized state.

FIG. 4 is an explanatory view showing a more specific structure of the air leak detection device 10 shown in FIG. Members having the same functions as those in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted.

The first type lower casing 14b having the measurement chamber 22 can be raised and lowered by an elevating mechanism such as an air cylinder 30 and can be brought into contact with and separated from the second type upper casing 14a. it can. As mentioned above, the measurement room 2
An O-ring 24, for example, is disposed as an airtight seal member around the circumference 2 in order to ensure the airtightness of the measurement chamber 22 in the closed state of the upper housing 14a and the lower housing 14b. Further, a block body 32 for connecting the switching valves Va and Vb can be closely connected to the upper housing 14a, and the switching valves Va, Vb and the switching valve Vc can be connected to the upper housing 14a and the block body 32. , Vd, etc., a switchable flow path 26 is formed. Further, the pressure sensor 18 is provided on the upper housing 14a.
Are built in and are connected to the flow path 26. In the upper housing 14a, the flow path 26 has two paths, that is, a path toward the measurement chamber 22 and a path connected to the pressure reducing device 16 via the switching valves Vc and Vd. It is connected to the flow path 26 which is connected to the valves Va and Vb. In the block body 32, the flow path 26 forms the reference pressure chamber 28 by the switching operation of the switching valves Va and Vb, and controls the communication and non-communication of the reference pressure chamber 28 with respect to the measurement chamber 22. Further, the switching valves Va to Vd are controlled by the control unit 20 (see FIG. 1).

As shown in FIGS. 5A to 5C, the block body 32 has at least a first surface 32a for mounting the switching valve Va and a second surface 32b for mounting the switching valve Vb.
It has three surfaces including a mold connecting surface 32c for connecting the upper housing 14a. In the present embodiment, the block body 32
Has a substantially triangular prism shape formed of metal, hard resin, or the like. As shown in FIG. 5 (a), the block body 32 includes a switching valve Va, that is, the first surface 32 a from the measurement chamber 22 side, that is, the mold connecting surface 32 c via the upper housing 14 a.
It has a flow path (passage) 26a directed to the first side and a flow path 26b directed from the first surface 32a to the second surface 32b. Further, it has a flow path 26c extending from the second surface 32b to the mold connecting surface 32c. The flow path 26c is connected to the pressure reducing device 16 via the switching valves Vc and Vd. As is clear from FIGS. 5A and 5C, since the first surface 32a and the mold connecting surface 32c and the second surface 32b and the mold connecting surface 32c are formed non-orthogonally, respectively, the block body When forming the flow paths 26a to 26c with respect to 32, the flow paths can be continuous at one point by, for example, drilling vertically from each surface. As a result, the flow path 2 easily communicated with each other.
6 can be formed. In addition, the flow paths 26a to 26c
Are formed at positions displaced so that they do not contact each other inside the block body 32. In addition, as shown in FIG. 5B, the flow path 26 a extending from the inside of the block body 32 and the block body 32.
The end surface of the flow path 26b directed to the inside is the first surface 32a.
It is folded back with exposed. Similarly, the flow path 26b extending from the inside of the block body 32 and the flow path 26c toward the inside of the block body 32 are folded back with their end faces exposed at the second surface 32b. The switching valve Va, is provided at the folded portion of the flow path 26 on the first surface 32a and the second surface 32b.
Vb is arranged to selectively block the flow path 26.

As described above, the block body 3 having a substantially triangular prism shape
The air leak detection device 1 is formed by forming the flow path 26 in 2 and mounting the switching valves Va, Vb and the upper casing 14a.
It is possible to combine the 0 flow path system parts compactly and simply, and the volume of the measurement tank 22 and the reference pressure chamber 28, that is, the volume of the measurement-related space is smaller than the volume of the internal space of the work 12. Therefore, it is possible to accurately detect a slight change in pressure when an air leak occurs. Further, in the block body 32 to which each member is attached, the flow passage 26 can be easily formed, and the simple flow passage 26 without air leakage can be formed. In the present embodiment, the case where the block body 32 has a substantially triangular prism shape has been described as an example, but the first surface 32a is used.
And mold connecting surface 32c and the second surface 32b and mold connecting surface 32
If c and c are formed non-orthogonally, the same effect can be obtained with other shapes.

FIG. 6 shows a fluid switching valve (for example, an air pressure switching valve) that can be used as the switching valves Va and Vb.
The switching valve Va has a first pressure chamber 34a and a second pressure chamber 34b through which compressed air flows in and out for driving the drive rod 34 that performs a valve switching operation. As the compressed air is discharged from the second pressure chamber 34b, the drive rod 34 descends in FIG.
The first port 36 to which 6a is connected and the second port 38 to which the flow path 26b is connected are separated, that is, the valve closing operation is performed. Conversely, compressed air is discharged from the first pressure chamber 34a and the second pressure chamber 34b is discharged. The drive rod 34 moves upward in FIG. 6 due to the inflow of compressed air into the flow path 26a and the flow path 26b.
Communication with, that is, a valve opening operation is performed.

An O-ring 40 as a first elastic member for pneumatically isolating the communication between the first port 36 and the second port 38 surrounds the first port 36 at the tip of the drive rod 34. It is located in. Further, on the side surface of the drive rod 34, the first port 36 is provided on the outer circumference of the O-ring 40.
An O-ring group 42 formed of a plurality of O-rings 42a is arranged as a second elastic member so as to block the outside air from the first port 36 and the second port 38 while surrounding both the second port 38 and the second port 38. Has been done. This O-ring group 42 is shown in FIG.
As is clear from the above, when the drive rod 34 is in the raised state, all of them come into close contact with each other in a predetermined compression state in the stacking direction, and block the first port 36 and the second port 38 from the outside air. Further, in a state where the drive rod 34 is lowered, each O-ring 42a is further compressed to enable the valve closing operation by the O-ring 40. That is, the stroke amount of the drive rod 34 is secured by the compression operation of the O-ring group 42. Of course, the stroke amount can be arbitrarily adjusted by the number of stacked O-rings 42a, and the number of O-rings 42a can be appropriately selected from one or more. In addition, O
When stacking a plurality of rings 42a, it is desirable to dispose spacers 44 in order to maintain mutual stability and adhesion.

As is apparent from FIG. 6, the drive rod 34
At, the air seal against the outside air is compressed O
Since it is executed by the ring group 42, there is no seal portion that slides on the inner wall surface or the like of the switching valve Va. That is, since the seal member does not come into contact with the inner wall surface or the like and slides unlike the conventional case, heat is not generated in the sliding portion and the sliding portion is not worn. As a result, the heat generation does not cause a pressure change when the air leak is detected, and the reliability of the measurement can be improved. Further, since the members are not slid, the durability of the O-ring 42a and the like is improved, and it is possible to prevent the measurement accuracy from being deteriorated due to a defective opening / closing operation.

FIG. 7 shows another structure of the switching valve Va. The switching valve Va shown in FIG. 7 also has a first pressure chamber 34a and a second pressure chamber 34b through which compressed air enters and leaves in order to drive the drive rod 34 that performs a valve switching operation, and the compressed air flows into the first pressure chamber 34a. The inflow and discharge of the compressed air from the second pressure chamber 34b lowers the drive rod 34 in FIG. 7, and the first port 36 to which the flow path 26a is connected and the second port 38 to which the flow path 26b is connected. Separate, that is, the valve closing operation is performed. On the contrary, when the compressed air is discharged from the first pressure chamber 34a and the compressed air flows into the second pressure chamber 34b, the drive rod 34 rises in FIG. 7, and the communication between the flow paths 26a and 26b, that is, Open the valve.

In the switching valve Va shown in FIG. 7, an elastic member 46 (for example, a rubber block) is arranged at the tip of the drive rod 34, and the valve base 4 forming the base of the switching valve Va.
First annular projection 50 and second annular projection 52 formed on
Can be contacted with. The valve base 48 has a first port 36 and a second port 38 formed therein, and the elastic member 46.
The first annular protrusion 50 is arranged so as to surround the first port 36 on the side facing. Further, a second annular protrusion 52 having a height higher than that of the first annular protrusion 50 is arranged so as to surround the first annular protrusion 50 and the second port 38. As is apparent from FIG. 7, the drive rod 34
The elastic member 46 disposed at the tip of the first rod 3 always contacts the second annular protrusion 52 when the drive rod 34 moves upward.
6 and the second port 38 are shut off from the outside air. At this time, the valve opening operation is performed by connecting the first port 36 and the second port 38 to each other. Further, when the drive rod 34 descends, the elastic member 46 contacts the second annular protrusion 52 and then the first annular protrusion 50 to separate the first port 36 and the second port 38, that is, the valve is closed. Take action.

As is apparent from FIG. 7, the drive rod 34
At the air seal for the outside air,
Since it is executed by the elastic member 46 that comes in contact with and separates from the No. 2, there is no seal portion that slides on the inner wall surface of the switching valve Va. That is, since the seal member does not contact the inner wall surface or the like and slides unlike the conventional case, heat is generated at the sliding portion,
The sliding parts do not wear. As a result, the heat generation does not cause a pressure change when the air leak is detected, and the reliability of the measurement can be improved. Also,
Since the members are not slid, the durability of the elastic member 46, which is a sealing member, is improved, and it is possible to prevent a decrease in measurement accuracy due to a defective opening / closing operation.

Since the switching valve structure shown in FIG. 7 is simpler than the switching valve structure shown in FIG.
It is easy to manufacture and has high reliability against air leaks. However, since the stroke amount of the drive rod 34 is only the difference between the protrusion heights of the first annular protrusion 50 and the second annular protrusion 52, the stroke cannot be extremely increased.
Therefore, it is not possible to secure a large flow path when the first port 36 and the second port 38 communicate with each other. Therefore, it is preferable to apply the switching valve structure of FIG. 7 to a device having a relatively small flow rate.

Incidentally, it is desirable to adopt the switching valve structure shown in FIGS. 6 and 7 for the switching valves Vc and Vd.

Further, the switching valve shown in FIGS. 6 and 7 is not limited to the air leak detection device, but is also applied to a device which needs to eliminate heat generation during valve operation and a device which is required to improve durability of its operating portion. It is possible to obtain the same effect.

The air leak detecting device to which the switching valve according to the present embodiment can be applied is shown below for reference. The air leak device includes a first mold having a measurement space of a predetermined volume in which a sealed container to be measured can be arranged, a second mold which engages with the first mold and selectively seals the measurement space, and the second mold. A block body having a passage connected to the second mold and communicating with the measurement space via the second mold to form a reference pressure space in a reference pressure state; and a predetermined position in the passage connected to the block body The pressure state of the reference pressure space is changed by selectively closing the at least two switching valves for controlling communication and non-communication of the passage with respect to the measurement space, and a pressure in at least the passage connected to the passage. And a pressure sensor for measuring the pressure in the passage or the measurement space,
The block body has at least three surfaces, a first surface and a second surface for mounting the switching valve, and a mold connecting surface for connecting the second mold, and the first surface, the mold connecting surface, and the second surface. The surface and the mold connecting surface are formed non-orthogonally,
A passage extending from the first surface and the mold connecting surface toward the inside of the block body, and a passage extending from the second surface and the mold connecting surface toward the inside of the block body are continuous at one point,
And the block body having a passage extending from the inside of the block body on the first surface and the second surface toward the inside of the block body by folding back with the end face exposed, and a reference pressure with respect to the measurement space in a predetermined pressure state. The presence or absence of air leak in the closed container to be measured is determined based on the pressure change when the space communicates.

In this case, since the reference pressure space is formed by the passage formed in the block body for fixing the switching valve and the second die, it is not necessary to use an air tube or the like, and the volume of the reference pressure space can be easily reduced. be able to. At this time, the block body has at least three surfaces of the first surface to which the switching valve is attached, the second surface, and the mold connecting surface, and the relationship is maintained in a non-orthogonal state, and the first surface side, the mold connecting surface side, and the second surface. Since each passage extending from the surface side and the mold connecting surface side is easily continuous at one point by, for example, drilling, it is easy to process and a block body having a simple structure is formed without using a blind cover or the like. be able to. Further, since the processing is easy, air leakage can be prevented.

Further, in the above structure, the switching valve is
The switching valve is a fluid-operated valve, which encloses the two rod end faces and a drive rod having a first elastic member that fluid-pressure-operates to come into contact with and separate from at least one of the end faces of the passage to close the passage. A second elastic member that allows the stroke movement of the drive rod while blocking the passage from the outside air;
Can be included.

In the above structure, the second elastic member may be formed by laminating one or a plurality of O-rings.

Further, in the above structure, the switching valve is a fluid operated valve, and the switching valve is a valve base having a communication passage communicating with the end face of the passage on one surface side and extending to the other surface side. A valve having a first annular projection that surrounds one of the communication passages on the other surface side and a second annular projection that has a higher projection height than the first annular projection that surrounds the first annular projection and the other communication passage A drive rod having a base and an elastic member that is operated by fluid pressure and is always in contact with the second annular projection, and selectively abuts the first annular projection to block the communication path by blocking the communication path. You can

In this case, since the drive rod does not include a sliding member in the seal portion, heat generation or wear does not occur at the time of valve switching, pressure measurement is not affected, and deterioration of measurement accuracy is prevented. You can

As described above, by using the switching valve without the block body and the sliding member, it is possible to reduce the size of the air leak detection device and improve the durability of the switching valve. It is possible to obtain an air leak detection device having a simple structure capable of highly accurately and stably detecting an air leak without being affected by the above.

[0053]

According to the present invention, since the drive rod does not include a sliding member in the seal portion, it has excellent durability and the operation of the switching valve does not affect other operations. As a result, when it is used in a direct pressure type air leak detection device, pressure measurement can be performed particularly stably.

[Brief description of drawings]

FIG. 1 is an explanatory diagram illustrating a configuration concept of an air leak detection device to which a switching valve according to an embodiment of the present invention can be applied.

FIG. 2 is a timing explanatory diagram showing the operation timing of the switching valve of the air leak detection device to which the switching valve according to the embodiment of the present invention can be applied.

FIG. 3 is an explanatory diagram illustrating a pressure change when each air leak occurs when the air leak detection device to which the switching valve according to the embodiment of the present invention is applicable is used.

FIG. 4 is an explanatory diagram illustrating a specific structure of the air leak detection device to which the switching valve according to the embodiment of the present invention can be applied.

FIG. 5 is an explanatory diagram illustrating the structure of the block body of the air leak detection device to which the switching valve according to the embodiment of the present invention can be applied.

FIG. 6 is an explanatory diagram illustrating the structure of the switching valve according to the embodiment of the present invention.

FIG. 7 is an explanatory diagram illustrating another structure of the switching valve according to the embodiment of the present invention.

[Explanation of symbols]

10 air leak detection device, 12 work, 12a internal space, 14 measuring tank, 14a upper housing, 14b lower housing, 16 pressure reducing device, 18 pressure sensor, 20 control unit, 22 measuring chamber, 24 O-ring, 26 flow path, Two
8 Reference pressure chamber, Va, Vb, Vc, Vd switching valve, 30
Air cylinder, 32 blocks.

Claims (3)

(57) [Claims] 1. A switching valve having a first port and a second port, which are internally connected to each other, wherein the first port and the second port are connected to and separated from the first port at a connecting portion of the first port and the second port. a drive rod having a first elastic member for switching the communicating and non-communicating port, with surrounding the connecting portion of the first port and a second port
The surface on which the connection portion is formed and the connection of the drive lot
An elastic member that comes into close contact with the surface facing the portion, and is configured to block the connecting portion from the outside air and to compress and deform the connecting portion .
Stroke of the first drive member is allowed in the direction of contact and separation of the first drive rod, and at the time of compression deformation, it does not contact the inner wall surface of the switching valve.
A second elastic member arranged at a sliding position, and a switching valve. 2. The switching valve according to claim 1, wherein the second elastic member is formed by laminating one or a plurality of O-rings. 3. A switching valve having a first port and a second port communicating with each other, wherein a first annular projection surrounding the first port at a connecting portion of the first port and the second port. A valve base having a second annular protrusion that surrounds the first annular protrusion and the second port and has a higher protrusion height than the first annular protrusion, and the first port that is always in contact with the second annular protrusion. And a drive rod having an elastic member that shuts off the connection portion of the second port from the outside air and selectively abuts the first annular protrusion to switch between communication and non-communication between the first port and the second port. A switching valve characterized by.