JP4118461B2 - Air leak test device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an air leak test apparatus for detecting minute leakage of a workpiece.
[0002]
[Prior art]
For example, an air leak test apparatus for detecting leakage of a small hollow part such as a small electronic part or a work such as a sealed container includes a common air passage whose base end is connected to a test pressure source, and a common air passage. First and second branch air passages branching from the tip are provided. The tips of the first and second branch air passages are connected to the master storage space and the work storage space, respectively. Each branch air passage is provided with an open / close valve (open / close valve). In the first and second branch air passages, a differential pressure sensor is connected between the passage portions on the tip side of the on-off valve.
[0003]
In the above air leak test apparatus, at the time of the test, the master part and the workpiece to be inspected are accommodated in the master accommodating space and the workpiece accommodating space, respectively, and the test is performed from the test pressure source to the master accommodating space and the workpiece accommodating space. Supply pressure. Thereafter, the master side system and the work side system are closed with the test pressure by closing the pair of on-off valves, and in this state, the presence or absence of work leakage based on the differential pressure detected from the differential pressure sensor. Determine.
[0004]
Conventionally, most of the common air passage and the first and second branch air passages are configured by pipes and connected to the open / close valve, the differential pressure sensor, the master, and the work accommodating space. The accuracy of leak detection could not be detected. The reason will be described in detail.
In the first and second branch air passages, the passage portion on the tip side of the on-off valve constitutes a closed system, but if these are formed by pipes, the volume of the closed system increases. Therefore, the differential pressure generated with respect to the workpiece leakage is reduced, and it becomes difficult to find a small leakage. In addition, since the tube is formed of a relatively soft material to facilitate bending, the volume of the closed system may change due to elastic deformation of the tube when a test pressure is applied. However, there was a limit to the improvement of detection accuracy.
[0005]
Therefore, in the air leak test apparatus disclosed in Japanese Patent Laid-Open No. 10-62296, the branch air passage is formed in a block over the entire length so as to reduce the volume of the branch air passage serving as a closed system and eliminate the fluctuation. I have to.
[0006]
[Problems to be solved by the invention]
In the air leak test apparatus disclosed in the above publication, the first and second branch air passages are formed in one block, and a differential pressure sensor, a pair of on-off valves, and the like are mounted on one surface, for example, the upper surface. However, in this configuration, the two input ports of the differential pressure sensor open to one surface of the differential pressure sensor and are connected to the first and second branch air passages of the block. The sensor became large, the shape of these input ports was complicated, and the volume was large.
Also, since two independent branch air passages are formed in the one block, it is necessary to maintain the symmetry of the branch air passage while avoiding interference between the on-off valves connected to these branch air passages. As a result, these branch air passages became long and their volume was large.
Therefore, the demand for reducing the volume of the closed system further and performing highly accurate leak detection could not be sufficiently answered.
[0007]
[Means for Solving the Problems]
According to a first aspect of the present invention, a common air passage whose base end is connected to a test pressure source, first and second branch air passages branched from the common air passage, and the first and second branches. An on-off valve provided in each of the air passages, and a differential pressure sensor for detecting a differential pressure between passage portions on the tip side of the on-off valves in the first and second branch air passages, Connect the master part and the workpiece to the 2-branch air passage, or connect the master storage space for storing the master component and the work storage space for storing the workpiece, respectively, and apply the test pressure from the test pressure source. In the air leak test apparatus for closing the on-off valve and detecting leakage of the workpiece based on the differential pressure detected by the differential pressure sensor in this state,
Adjacent first and second blocks are provided, and the first and second blocks are formed with the first and second branch air passages, respectively, and open and close the first and second branch air passages. Each open / close valve is attached,
Further, on the surfaces of the first and second blocks facing each other, there are opened connection holes respectively connected to the tip side passage portions of the first and second branch air passages,
The differential pressure sensor is disposed between the opposing surfaces of the first and second blocks, and the two pressure introduction ports of the differential pressure sensor are connected to the connection holes of the first and second blocks. It is characterized by being connected to each other.
[0008]
According to a second aspect of the present invention, in the air leak test apparatus according to the first aspect, the differential pressure sensor has a pair of convex portions that open the pressure introduction port, and the convex portions are the first and second blocks. It is characterized by being inserted into the connection hole.
According to a third aspect of the present invention, the air leak test apparatus according to the first and second aspects further includes a third block, and the first and second blocks are arranged on one surface of the third block. The third block is characterized in that a linear through hole is formed as an extension of the tip side passage portion of the first and second branch air passages.
According to a fourth aspect of the present invention, in the air leak test apparatus according to the third aspect, the common air passage is further formed in the third block, and the common air passage is on the tip side of the first and second branch passages. It is characterized by being connected to the first and second branch passages of the first and second blocks without crossing the extension of the passage portion.
[0009]
According to a fifth aspect of the present invention, in the air leak test apparatus according to the third and fourth aspects, the on-off valve is mounted on a surface orthogonal to the facing surface in the first and second blocks,
The first and second blocks include a first hole that extends linearly from the connection hole perpendicular to the facing surface, and a linear hole that extends orthogonally to the first hole and extends to the through hole of the third block. A continuous second hole and a third hole that linearly extends perpendicular to the first hole, opens on the surface on which the on-off valve is mounted, and is opened and closed by the on-off valve are formed. The distal end side passage portion of the branch air passage is constituted by the second and third holes.
In the air leak test apparatus of the sixth aspect of the present invention, a tank is mounted on the first and second blocks along with the on / off valve on the mounting surface of the on / off valve, and an auxiliary on / off valve is accommodated in the tank. And
Further, the first and second blocks are formed with a fourth hole that extends linearly perpendicular to the first hole, opens to the surface on which the tank is mounted, and is opened and closed by the auxiliary on-off valve. It is characterized by that.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
A first embodiment of the present invention will be described below with reference to FIGS. First, an outline of the air leak test apparatus will be described with reference to the circuit diagram of FIG.
The air leak test apparatus includes an air passage 1. The air passage 1 has a common air passage 1x and first and second branch air passages 1a and 1b branched from the downstream end (tip) thereof. A compressed air pressure source 2 (test pressure source) is connected to the upstream end (base end) of the common air passage 1x. The common air passage 1x is provided with a regulator 3 and a three-way solenoid valve 4 in order from the upstream side. The three-way solenoid valve 4 has a test pressure supply position where the pair of branch air passages 1a, 1b and the compressed air source 2 are communicated with each other, and the pair of branch air passages 1a, 1b are cut off from the compressed air pressure source 2 and opened to the atmosphere. One of the atmospheric release positions to be selected is selected, and is in the atmospheric release position in the off state.
[0011]
In the middle of the branch air passages 1a and 1b, normally open pneumatically driven on-off valves 5a and 5b are provided, respectively. Hereinafter, in the branch air passages 1a and 1b, the portion between the on-off valves 5a and 5b and the upstream end is referred to as upstream passage portions 1a ′ and 1b ′ (base end-side passage portions), and the on-off valves 5a and 5b and the downstream end are referred to as upstream passage portions 1a ′ and 1b ′. These are referred to as downstream passage portions 1a "and 1b" (front end passage portions).
[0012]
A pair of input ports 6a and 6b of the differential pressure sensor 6 are connected to midway portions of the downstream side passage portions 1a "and 1b" of the branch air passages 1a and 1b via pressure introduction passages 1c and 1d, respectively. . The differential pressure sensor 6 has a diaphragm inside, and converts the deformation of the diaphragm according to the pressure difference between the pair of input ports 6a and 6b into a voltage and outputs the voltage.
Further, tanks 7a and 7b having the same volume are connected to the downstream passage portions 1a "and 1b" of the branch air passages 1a and 1b via connecting passages 1e and 1f and auxiliary on-off valves 8a and 8b, respectively. Has been.
[0013]
A master accommodating space 9a for accommodating the master part M is connected to the downstream end of the first branch air passage 1a, and the work W ((2) to be inspected is connected to the downstream end of the second branch air passage 1b. For example, a work accommodating space 9b for accommodating a precision electronic component or the like is connected. The master part M is, for example, the same part as the workpiece W, and it has been confirmed that no leakage occurs.
[0014]
Further, the air leak test apparatus has a control unit 10. The control unit 10 includes a microcomputer, a memory, an input / output interface, driving means, and the like (all not shown). A detection signal from the differential pressure sensor 6 is input to the control unit 10. The control unit 10 has a function of controlling the three-way solenoid valve 4, the on-off valves 5a and 5b, the auxiliary on-off valves 8a and 8b, the display 11, the pass lamp 12, and the fail lamp 13.
[0015]
When performing a workpiece leak test using the air leak test apparatus having the above configuration, first, the master article M and the workpiece W are accommodated in the respective accommodating spaces 9a and 9b, and the accommodating spaces 9a and 9b are sealed. .
Next, the three-way solenoid valve 4 is turned on, and the test pressure is supplied to the master storage space 9a and the work storage space 9b via the branch air passages 1a and 1b.
Next, by closing the on-off valves 5a and 5b, the system including the downstream passage portion 1a "of the first branch air passage 1a and the master accommodating space 9a is closed with the test pressure, and the second branch air passage 1b The system including the downstream-side passage portion 1b ″ and the work accommodating space 9b is also closed with the test pressure.
[0016]
When the workpiece W accommodated in the workpiece accommodating space 9b is not damaged, pressurized air does not enter the workpiece W, and the pressure of the closed system on the workpiece side is not different from the pressure of the closed system on the master side. The detected differential pressure after the elapse of the predetermined time is zero, and the control unit 10 calculates the atmospheric pressure equivalent leakage amount as zero based on this differential pressure zero.
When there is a minute scratch on the workpiece W, pressurized air enters the workpiece W, so that the pressure of the workpiece side closing system decreases accordingly, and the differential pressure sensor 6 responds to the differential pressure corresponding to the leak. Is detected. The control unit 10 calculates a leak amount in terms of atmospheric pressure corresponding to this differential pressure.
The control unit 10 displays the atmospheric pressure conversion leak amount calculated as described above on the display 11 and performs leak determination by comparing with the threshold value. When the amount of leakage is smaller than the threshold value, it is determined that the workpiece W has no minute leakage, and when it is larger than the threshold value, it is determined that there is minute leakage.
[0017]
Next, the auxiliary on-off valves 8a and 8b of the tanks 7a and 7b are opened to release the pressures of the master side closing system and the work side closing system to the internal spaces of the tanks 7a and 7b in the atmospheric pressure state (pseudo leak). Thereafter, the differential pressure is detected again by the differential pressure sensor 6. This detected differential pressure is compared with a threshold value different from the above to determine whether there is a large leak.
[0018]
The principle of the large leak determination is as follows. When there is a large scratch on the workpiece W, the pressurized air is sunk inside the workpiece W when the test pressure is applied, and the inside of the workpiece W becomes the test pressure. Thereafter, even if the on-off valves 5a and 5b are closed and the differential pressure is detected, the differential pressure is substantially zero and it is determined that there is no minute leak. Therefore, as described above, an equal amount of pseudo-leakage is generated in the master side closed system and the work side closed system. When the inside of the workpiece W is at a test pressure due to a large leak, the pressure in the workpiece side closing system becomes higher than expected after the pseudo leak. In other words, when there is a large leak, a difference corresponding to the internal volume of the workpiece W appears between the volumes of the closed system on the master side and the workpiece side. Since the difference in volume in the test pressure state appears as a differential pressure due to the pseudo leak, it is possible to determine whether there is a large leak.
[0019]
For a workpiece W that has been determined to have no microleakage and no major leak, the corresponding acceptance lamp 12 is turned on as being non-defective, and if there is a microleakage or large leak, it is determined that the workpiece W is defective. The corresponding failure lamp 13 is turned on.
Next, the control unit 10 brings the three-way solenoid valve 4 to the atmospheric release position and opens the on-off valves 5a and 5b, thereby opening the master accommodation space 9a and the work accommodation space 9b to the atmosphere, and then the tanks 7a and 7b. The auxiliary on-off valves 8a and 8b are closed.
[0020]
Next, a specific structure of the air leak test apparatus will be described with reference to FIGS. This air leak test apparatus can inspect a plurality of, for example, five workpieces simultaneously. 2 to 4, most of the common air passage 1x, the compressed air pressure source 2, the regulator 3, and the three-way solenoid valve 4 are not shown.
[0021]
As shown in FIG. 2, the air leak test apparatus includes a horizontal table 15. This table 15 is formed with a rectangular hole 15a, and a plurality of, for example, five base blocks 20 (third blocks) each having a rectangular parallelepiped shape elongated in the left and right sides are inserted in the hole 15a in a direction perpendicular to the paper surface. Has been.
The base block 20 has a flange 21 projecting horizontally, and the flange 21 is fixed to the upper surface of the table 15. A rectangular parallelepiped shaped receiving block 25 is fixed to the left and right sides of the flat bottom surface of each base block 20. The lower surface of the receiving block 25 is provided as a flat flat mating surface 25x.
[0022]
Below the receiving blocks 25, a lifting platform 30 is arranged. The lift 30 is moved up and down by a drive mechanism (not shown). A master capsule 35 </ b> A and a work capsule 35 </ b> B are provided on the upper surface of the lift 30 so as to be separated from each other in the left-right direction. The upper surfaces of the capsules 35A and 35B have the same height and are provided as horizontal flat mating surfaces 35x. The mating surface 35x is in contact with the mating surface 25x of the receiving block 25 at the raised position of the lifting platform 30.
In the center of the mating surface 35x of the capsules 35A and 35B, a concave portion constituting the master accommodating space 9a and a concave portion having the same volume constituting the workpiece accommodating space 9b are formed.
[0023]
A master block 40A (first block) and a work block 40B (second block) of the same shape, which are paired side by side, are attached to the horizontal flat upper surface of each base block 20.
[0024]
A master valve block 50A and a work valve block 50B made of a non-magnetic material are fixed to the upper surfaces of the blocks 40A and 40B, respectively. The valve block 50A incorporates the master-side on-off valve 5a, tank 7a, and auxiliary on-off valve 8a in FIG. 1, and the valve block 50B includes the work-side on-off valve 5b, tank 7b, and auxiliary on-off valve 8b. Built-in.
An amplifier 60 that amplifies the output signal of the differential pressure sensor 6 is fixed to the side surface of the valve block 50B.
[0025]
Next, the passage structure of the blocks 20, 25, 40A, 40B will be described in detail with particular reference to FIG. Each receiving block 25 is formed with two vertical through holes 25a and 25b having the same diameter and the same volume that are separated from each other on the left and right sides, and each base block 20 is airtight to the through holes 25a and 25b. Are formed with vertical through holes 20a and 20b having the same diameter and the same volume. The through holes 20a and 25a are provided as extensions of the downstream passage portion 1a ″ of the first branch air passage 1a, and the through holes 20b and 25b are downstream passages of the second branch air passage 1b. Provided as an extension of part 1b ".
[0026]
An annular groove is formed on the mating surface 25x of the receiving block 25 so as to surround the lower end openings of the through holes 25a and 25b, and seal rings 27 are fitted into the grooves, respectively.
When the lifting platform 30 is raised and the mating surface 35x of the capsules 35A and 35B comes into contact with the mating surface 25x of the receiving plate 25, the receiving spaces 9a and 9b of the capsules 35A and 35B are sealed by the seal ring 27 and received. The block 25 communicates with the vertical through holes 20a and 20b.
[0027]
The base block 20 is further formed with a horizontal hole 22 having a large diameter that extends horizontally and linearly. The horizontal hole 22 constitutes a downstream portion of the common air passage 1x described above. The horizontal hole 22 is closed at the right end with a plug, and the left end is connected to the pipe of the common air passage 1x via a joint 23 (see FIG. 2). Two short vertical holes 24 extend upward from the common air passage 1 x and open to the upper surface of the base block 20. Of course, the horizontal holes 22 and the vertical holes 24 do not intersect with the above-described through holes 20a and 20b.
[0028]
The blocks 40 </ b> A and 40 </ b> B have a facing surface 41. The above-described differential pressure sensor 6 is sandwiched between the facing surfaces 41. Convex portions 6x in which the input ports 6a and 6b (see FIG. 1) are opened are formed on both surfaces of the differential pressure sensor 6, and these convex portions 6x are airtight in connection holes 42 opened in the facing surface 41. Has been inserted.
[0029]
In the blocks 40A and 40B, the first and second branch air passages 1a and 1b are formed. These branch air passages 1a and 1b are composed of a plurality of holes that are drilled with a drill and extend linearly.
More specifically, the master block 40A is formed with a horizontal hole 43 (first hole) that extends horizontally from the connection hole 42 and perpendicular to the facing surface 41. The other end of the horizontal hole 43 opens to the side surface of the block 40A and is closed by a dummy block 61. A vertical hole 44 (second hole) extends downward from an intermediate portion of the horizontal hole 43 and opens on the lower surface of the block 40A, and is continuous with the through hole 20a of the base block 20 described above.
[0030]
On the upper surface of the block 40A, valve seats 45 and 45 'for the above-described on-off valve 5a and auxiliary on-off valve 8a are formed apart from each other on the left and right. The valve seat 45 is disposed close to the facing surface 41, and the valve seat 45 ′ is disposed away from the facing surface 41. In these valve seats 45 and 45 ′, upper ends of a vertical hole 46 (third hole) and a vertical hole 46 ′ (fourth hole) extending upward from the horizontal hole 43 are opened. The horizontal hole 43 and the vertical holes 44 and 46 are provided as a downstream passage portion 1a "of the branch air passage 1a. The vertical hole 46 'is provided as a communication passage 1e to the tank 7a. The
[0031]
Further, the block 40A is formed with a vertical hole 47 opened on its lower surface and a horizontal hole 48 connected to its upper end. The vertical hole 47 is connected to the horizontal hole 22 (common air passage 1x) via the vertical hole 24 of the base block 20. The horizontal hole 48 opens on the facing surface 41 and is closed with a stopper. Further, as shown in FIG. 4, a vertical hole 49 extending upward from the horizontal hole 48 is formed, and the vertical hole 49 is opened on the upper surface of the block 40 </ b> A in the vicinity of the valve seat 45. The vertical holes 47 and 49 and the horizontal hole 48 constitute an upstream portion 1a ′ of the first branch air passage 1a.
[0032]
Since the work block 40B also has the same passage structure as that of the master block 40A, the same reference numerals are given in the drawing and the detailed description thereof is omitted. The difference is that the horizontal hole 43 does not penetrate the block 40A, but instead has a short horizontal hole 43 'that continues to the vertical hole 46'. For the diagnosis of the differential pressure sensor 6, a volume changer 65 (see FIG. 2) that performs pseudo leakage is connected to the horizontal hole 43 ′. Normally, the horizontal hole 43 ′ is a dummy hole. Blocked with a block 66.
[0033]
In the work block 40B, the horizontal hole 43 and the vertical holes 44, 46 are provided as the downstream passage portion 1b "of the second branch air passage 1b. The vertical hole 46 'is the tank described above. The vertical holes 47 and 49 and the horizontal holes 48 constitute the upstream portion 1b ′ of the second branch air passage 1b, and the blocks 40A and 40B are arranged upstream. The side passage portions 1a ′ and 1b ′ have the same volume, and the downstream passage portions 1a ″ and 1b ″ also have the same volume.
[0034]
Next, the internal structure of the valve blocks 50A and 50B will be described with reference to FIG. The master-side valve block 50 </ b> A has a lower chamber 52 and an upper chamber 53 that are partitioned by a partition wall 51 on the left and right sides thereof. In the lower chamber 52 on the right side, the downstream vertical hole 46 and the upstream vertical hole 49 of the first branch air passage 1a face, and the valve body 54 of the on-off valve 5a is slidably accommodated in the vertical direction. Has been. The left lower chamber 52 is provided as the tank 7a described above, and the valve element 54 of the auxiliary on-off valve 8a is slidably accommodated therein. An armature 55 is accommodated in the left and right upper chambers 53 so as to be slidable in the vertical direction. An input port 56 at the upper end of the armature 55 is connected to a compressed air source via a solenoid valve (not shown). This electromagnetic valve is controlled by the control unit 10.
[0035]
The valve body 54 is biased by a coil spring in a direction away from the valve seats 45 and 45 ′ and is in the open position. When compressed air is applied from the input port 56, the armature 55 moves downward, and the armature 55 The valve body 54 is moved downward by the repulsive force of the magnet provided on the valve body 54 and is seated on the valve seats 45 and 45 'to be in the closed position.
[0036]
The work valve block 50B is also symmetrical with the master valve block 50A, and the lower chamber 52 on the right side is provided as the tank 7b described above. The left valve body 54 belongs to the on-off valve 5b, and the right valve body 54 belongs to the auxiliary on-off valve 8b.
[0037]
As is clear from the above description, in FIG. 1, air passages in a range surrounded by an imaginary line S are formed in the blocks 20, 25, 40A, and 40B. Although only one circuit S is shown in FIG. 1, the common air passage 1 x is branched on the downstream side of the three-way electromagnetic valve 4 and connected to the five circuits S.
[0038]
When performing a workpiece leak test using the air leak test apparatus having the above-described configuration, the master parts M are accommodated in the recesses 9a of the five capsules 35A in advance. Then, the five workpieces W to be inspected are accommodated in the recesses 9b of the five capsules 35B, and the leak test is performed as described above.
[0039]
In the above air leak test apparatus, the branch air passages 1a and 1b are formed in the blocks 20, 25, 40A and 40B, including the extension on the tip side, and pipes are not used, so the volume of the branch air passages 1a and 1b is increased. In particular, the volume of the downstream passage parts 1a ", 1b", i.e. the closed system, can be reduced. In addition, since the cross-sectional area of the drilled hole does not change when the test pressure is applied, the volume change of the closed system due to the test pressure can be eliminated. Furthermore, a member for connecting the passages is not required, and the possibility of leakage here can be eliminated. As a result, it is possible to increase the sensitivity of leak detection due to differential pressure, and it is possible to stably detect minute leaks of precision small parts with high reliability.
[0040]
Further, in the present embodiment, the differential pressure sensor 6 is sandwiched between the blocks 40A and 40B. The differential pressure sensor 6 has input ports 6a and 6b arranged on both sides, and the input ports 6a and 6b Since it is formed in a straight line at right angles toward the central diaphragm 6c (see FIG. 3), the differential pressure sensor 6 can be reduced in size and the structure of the input ports 6a and 6b can be simplified and shortened. As a result, it contributes to the volume reduction of the closed system, and more accurate leak detection can be performed.
Moreover, since the first and second branch air passages 1a and 1b are formed in separate blocks 40A and 40B as described above, the passage structure can be simplified and shortened. It can contribute to the volume reduction of the system.
[0041]
Further, the convex portion 6x of the differential pressure sensor 6 is connected to the block 4A. Since it is inserted into the connection hole 42 formed on the facing surface 41 of 4B, the input ports 6a and 6b of the differential pressure sensor 6 and the branch air passages 1a and 1b can be communicated with each other with good airtightness. Support is also certain.
[0042]
Since the blocks 40A and 40B in which the branch air passages 1a and 1b are formed are fixed to the common base block 20, stable support is achieved. Further, since the common air passage 1x is formed in the base block 20 and is connected to the branch air passages 1a and 1b of the blocks 40A and 40B, the circuit configuration can be simplified.
[0043]
In the blocks 40A and 40B, the differential pressure sensor 6 is disposed on the facing surface 41, and is disposed on the upper surface intersecting the on-off valves 5a and 5b and the facing surface 41. Therefore, a plurality of relatively short holes 43 and 44 are provided. , 46 can constitute downstream passage portions 1a ", 1b" of the branch air passages 1a, 1b. Therefore, these holes 43, 44, 45 can be formed with a thin drill, and this point can also contribute to the volume reduction of the closed system.
[0044]
In the above embodiment, in the blocks 40A and 40B, the vertical hole 44 can be connected to an arbitrary position of the horizontal hole 43. Therefore, the through holes 20a and 25a and the through holes 20b and 25b corresponding to the vertical hole 44 are connected to each other. The position can be arbitrarily selected over a wide range, and the positions of the capsules 35A and 35B can be arbitrarily selected over a wide range.
[0045]
FIG. 5 shows a second embodiment of the present invention. In this embodiment, a master part (not shown) and the workpiece W are connected to the two seal rings 27 of the receiving block 25 so as to directly contact each other. In this embodiment, the workpiece W is an electromagnetic valve, and the sealing performance of the valve port Wb is inspected in a state where the valve Wa of the electromagnetic valve hits the valve seat by a spring (not shown). The work W is pressed against the receiving block 25 by a guide mechanism (not shown) or mounting means including a pressing cylinder 70 (pressing mechanism), and a very small space constituting the valve port Wb is an opening of the through hole 25b. It continues to. The master part always contacts the seal ring 27 and communicates with the through hole 25a, but is not shown here.
[0046]
The receiving plate 25 is used so that it can be easily replaced when damaged, but may be omitted. In that case, the capsules 35A and 35B are applied to the base block 20, or the workpiece and master parts are applied directly.
[0047]
【The invention's effect】
As described above, according to the first aspect of the present invention, the branch air passages 1a and 1b are formed in blocks and pipes are not used, so that the volume of the branch air passage can be reduced. The volume of the part or closed system can be reduced. In addition, since the cross-sectional area of the drilled hole does not change when the test pressure is applied, the volume change of the closed system due to the test pressure can be eliminated. As a result, it is possible to increase the sensitivity of leak detection due to differential pressure, and it is possible to stably detect minute leaks of precision small parts with high reliability.
Moreover, since the first and second branch air passages are separately formed in the first and second blocks, respectively, the passage structure can be simplified and shortened, contributing to the volume reduction of the closed system, More accurate leak detection can be performed.
Further, since the differential pressure sensor is sandwiched between the first and second blocks, the differential pressure sensor can be reduced in size and the structure of the input port of the differential pressure sensor can be simplified and shortened. As a result, it contributes to the volume reduction of the closed system, and more accurate leak detection can be performed.
[0048]
According to the second aspect of the present invention, since the convex portion of the differential pressure sensor is inserted into the connection hole formed on the opposite surface of the block, the input port of the differential pressure sensor and the branch air passage are communicated with each other with good airtightness. In addition, the differential pressure sensor can be reliably supported.
According to the 3rd aspect of this invention, since the 1st, 2nd block which formed the branch air path is being fixed to the common 3rd block, the stable support is made | formed.
According to the fourth aspect of the present invention, since the common air passage is formed in the third block and connected to the branch air passage of the block, the circuit configuration can be simplified.
[0049]
According to the fifth aspect of the present invention, in the first and second blocks, the differential pressure sensor is disposed on the facing surface, and is disposed on a surface intersecting the facing valve and the facing surface. The downstream side passage portion of the branch air passage can be constituted by a plurality of short straight holes. Therefore, these holes can be narrowed to contribute to the volume reduction of the closed system.
According to the sixth aspect of the present invention, even if a tank is used, the volume of the closed system is remarkably increased by devising the installation location of the tank and the formation of the passage connecting the tank and the branch air passage. You do n’t have to.
[Brief description of the drawings]
FIG. 1 is a circuit diagram of an air leak test apparatus according to a first embodiment of the present invention.
FIG. 2 is a front view showing the air leak test apparatus with a partial cross section.
FIG. 3 is an enlarged longitudinal sectional view of the air leak test apparatus.
4 is a cross-sectional view of main parts taken along line IV-IV in FIG. 3;
FIG. 5 is a cross-sectional view of a main part of an air leak test apparatus according to a second embodiment of the present invention.
[Explanation of symbols]
M Master part
W Work
1x Common air passage
1a First branch air passage
1b Second branch air passage
1a ′, 1b ′ Upstream side passage portion (base end side passage portion)
1a ", 1b" Downstream side passage part (tip side passage part)
2 Compressed air source (test pressure source)
5a, 5b Open / close valve (open / close valve)
6 Differential pressure sensor (pressure sensor)
6a, 6b Input port
6x convex part
7a, 7b tank
8a, 8b Auxiliary on-off valve
9a Master storage space
9b Work space
20 Base block (third block)
20a, 20b through-hole (extension part of tip side passage part)
22 Horizontal hole (common air passage)
40A Master block (first block)
40B Work block (2nd block)
41 Face to face
42 Connection hole
43 Horizontal hole (1st hole)
44 Vertical hole (second hole)
46 Vertical hole (3rd hole)
46 'vertical hole (fourth hole)

Claims (6)

Common air passage whose base end is connected to the test pressure source, first and second branch air passages branching from the common air passage, and on-off valves respectively provided in the first and second branch air passages And a differential pressure sensor for detecting a differential pressure between the passage portions on the tip side of the on-off valve in the first and second branch air passages, the master parts in the first and second branch air passages, Connect the workpieces respectively, or connect the master storage space for storing the master parts and the work storage space for storing the workpieces, apply test pressure from the test pressure source and close the open / close valve. In an air leak test device that detects a leakage of a workpiece based on a differential pressure detected by the differential pressure sensor,
Adjacent first and second blocks are provided, and the first and second blocks are formed with the first and second branch air passages, respectively, and open and close the first and second branch air passages. Each open / close valve is attached,
Further, on the surfaces of the first and second blocks facing each other, there are opened connection holes respectively connected to the tip side passage portions of the first and second branch air passages,
The differential pressure sensor is disposed between the opposing surfaces of the first and second blocks, and the two pressure introduction ports of the differential pressure sensor are connected to the connection holes of the first and second blocks. Air leak test equipment characterized by being connected to each other. 2. The differential pressure sensor according to claim 1, wherein the differential pressure sensor has a pair of convex portions in which the pressure introduction port opens, and the convex portions are inserted into connection holes of the first and second blocks. Air leak test equipment. Further, a third block is provided, and the first and second blocks are fixed side by side on one surface of the third block, and the first and second branch airs are arranged in the third block. The air leak test apparatus according to claim 1 or 2, wherein a linear through-hole that forms an extension of a passage portion on the distal end side of the passage is formed. The common air passage is further formed in the third block, and the common air passage does not intersect with the extension of the distal end side passage portion of the first and second branch passages, and the first block of the first and second blocks. The air leak test apparatus according to claim 3, wherein the air leak test apparatus is connected to the second branch passage. The on-off valve is mounted on a surface orthogonal to the facing surface in the first and second blocks,
The first and second blocks include a first hole that extends linearly from the connection hole perpendicular to the facing surface, and a linear hole that extends orthogonally to the first hole and extends to the through hole of the third block. A continuous second hole and a third hole that linearly extends perpendicular to the first hole, opens on the surface on which the on-off valve is mounted, and is opened and closed by the on-off valve are formed. 5. The air leak test apparatus according to claim 3, wherein a tip side passage portion of the branch air passage is constituted by the second and third holes. In the first and second blocks, a tank is mounted on the mounting surface of the on-off valve along with the on-off valve, and an auxiliary on-off valve is accommodated in the tank,
Further, the first and second blocks are formed with a fourth hole that extends linearly perpendicular to the first hole, opens to the surface on which the tank is mounted, and is opened and closed by the auxiliary on-off valve. The air leak test apparatus according to claim 5.

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