Air leak inspection jig

Abstract

To provide an air leak inspection tool capable of performing air leak inspection in a short time by an inexpensive pressure sensor having no air pump.SOLUTION: An air leak inspection tool 100 is used for a workpiece A having a sealing surface A6 surrounding an inspection object place A7 which is an object of air leak inspection. In the air leak inspection jig 100, the work A is set in the pressure supply chamber 1 opened in the upper surface 11 of the work base 10 so as to accommodate the inspection target place A6, and the work A is pressurized from above, whereby the work base 10 and the piston 21 connected to the lower part of the work base 10 are slid via the sealing surface A7 of the work A, and the negative pressure generated by expanding the volume of the pressure forming chamber 22d in the cylinder 22 is supplied to the pressure supply chamber 1.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an inspection jig used for air leak inspection, and more particularly to an inspection jig for air leak inspection that uses a piston to reduce or increase the pressure in the space around the inspection target portion of a workpiece. [Background technology]

[0002] The inventors have performed air leak inspections of antenna connectors (hereinafter referred to as "work A") as shown in Figures 4 and 5 using an inspection jig 900 as shown in Figures 6 and 7. As shown in Figure 4, work A includes an outer tube A1, a core wire A2 inserted into the outer tube A1, a diamond-shaped flange A3 extending outward from the outer tube A1, a resin layer A4 filling the gap between the outer tube A1 and the core wire A2, and an adhesive layer A5 filling a recess A21 at one end of the outer tube A1 (upper side in Figure 4, lower side in Figure 5). Work A is assumed to have leak paths L1 and L2 as shown in Figure 5, and to seal these paths, an adhesive is applied to the surface of the resin layer A4 to form an adhesive layer A5.

[0003] 7, the conventional inspection jig 900 described above includes a plate-shaped work base 910 having a plurality of pressure measurement chambers 901 provided on an upper surface 911. The plurality of pressure measurement chambers 901 are connected by communication passages 902, and are configured so that an air leak test can be performed by evacuating all of the pressure measurement chambers 901 from a measurement pipe 904 provided in one of the pressure measurement chambers 901 using an air leak tester (not shown) with an electric pump.

[0004] When inspecting workpiece A using inspection jig 900, inspection jig 900 is placed on pressure device B as shown in Fig. 6. Workpiece A is set so that the pressure measurement chamber 901 of inspection jig 900 is covered from above and flange A3 is placed on the periphery of pressure measurement chamber 901. Gasket 903 is provided between flange A3 and workpiece base 910. In this state, pressure is applied to workpiece A from above by pressure shaft B2 of pressure device B to airtightly seal pressure measurement chamber 901, and the pressure measurement chamber is depressurized using an air leak tester via measurement tube 904 to check whether negative pressure is maintained.

[0005] However, in this conventional inspection jig 900, because the multiple pressure measurement chambers 901 are connected, multiple workpieces A can be inspected simultaneously, but the inspection does not pass unless all of the workpieces A are non-defective, and if they fail, the inspection must be repeated while replacing the workpieces A to identify the defective ones. Also, to inspect the workpieces A individually without connecting the pressure measurement chambers 901, there was the problem that expensive air leak testers would be required for each pressure measurement chamber.

[0006] Therefore, the inventors came up with the idea of ​​using a pressure device that pressurizes the workpiece against the workpiece base to operate a piston to reduce the pressure inside the pressure measurement chamber, and then measuring the pressure inside the pressure measurement chamber directly with a pressure sensor. In this way, an expensive air leak tester can be replaced with an inexpensive pressure sensor.

[0007] Meanwhile, Patent Document 1 discloses a leak inspection method for a sealed container in which the pressure around the inspection target point is increased or decreased by a piston to inspect the workpiece for air leaks.

[0008] In Patent Document 1, the bottle mouth of a beverage bottle, which is sealed with a screw cap, is placed in a pressure measurement chamber (test pocket) that opens downward, and the pressure in the pressure measurement chamber is reduced by a piston that slides inside a cylinder that is connected to the pressure measurement chamber.The pressure sampled through a pipe branching off from the pipe that connects the pressure measurement chamber to the cylinder is measured by a pressure sensor to test for leaks in the beverage bottle. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Special Publication No. 7-113592 Summary of the Invention [Problem to be solved by the invention]

[0010] However, the leak inspection method of Patent Document 1 requires pressurizing an O-ring to seal the pressure measurement chamber, and then operating a piston to create a negative pressure in the pressure measurement chamber, which results in problems such as a long inspection time and a complex device because the mechanism for pressurizing the O-ring and the mechanism for operating the piston are separate mechanisms. The present invention has been made in view of the above-mentioned problems, and has as its object to provide an air leak inspection tool that can perform air leak inspection efficiently without requiring an expensive air leak tester. [Means for solving the problem]

[0011] The invention made to solve the above problems is an air leak inspection tool that targets a workpiece having a sealing surface surrounding a target area for air leak inspection, and that contains the target area in a pressure measurement chamber of a workpiece base having a pressure measurement chamber that opens on one side, and presses the workpiece with a pressure device to press the sealing surface against the periphery of the pressure measurement chamber of the workpiece base, thereby sealing the pressure measurement chamber, and has a piston rod on one side and a piston head on the other side opposite to the one side, and one side of the piston rod is connected to the other side of the workpiece base. the pressure generating device is characterized in that it comprises a piston that slides together with the work base by pressurizing the work base from one side via the sealing surface of the work, a cylinder that slidably accommodates the piston head of the piston, a pressure generating chamber consisting of a space on one side or the other side of the piston head in the internal chamber of the cylinder, in which pressure is generated by pressurizing or depressurizing the fluid in the internal chamber of the cylinder as the piston slides, a pressure supply path that connects the pressure measuring chamber and the pressure generating chamber, and a pressure sensor that measures the pressure in the pressure measuring chamber.

[0012] In this way, in the air leak inspection jig of the present invention, the pressure generation chamber provided in the internal chamber of the cylinder and the pressure measurement chamber for applying pressure to the inspection target portion of the workpiece are connected by a pressure supply path, so that the positive or negative pressure generated in the pressure generation chamber by the sliding of the piston can be supplied to the pressure measurement chamber. The pressure device pressurizes the sealing surface of the workpiece against the work base from one side, pressurizing and sliding the piston connected to the other end side via the work base, so that the sealing of the pressure measurement chamber and the sliding of the piston for depressurizing or pressurizing the pressure measurement chamber can be performed simultaneously.

[0013] In the air leak inspection jig of the present invention, the one side is preferably the upper side. In other words, by opening the pressure measurement chamber above the work base, the work can be set in the pressure measurement chamber from above, making it easy to set the work.

[0014] In the air leak inspection jig of the present invention, it is preferable that the piston rod has a piston base on one side, and the work base is detachably connected to the piston base, so that the work base can be easily replaced with another work base having a pressure measurement chamber for a different workpiece.

[0015] The pressure supply path is preferably made of a flexible tube. In the air leak inspection jig of the present invention, the pressure measurement chamber and the pressure generation chamber approach each other when the pressurizing device pressurizes the work base. By forming the pressure supply path using a flexible tube, the pressure supply path can be deformed in accordance with the approach of the pressure generation chamber and the pressure measurement chamber.

[0016] In the air leak inspection jig of the present invention, it is preferable that an air filter is provided in the pressure supply path, thereby making it possible to prevent dust from entering the cylinder from the pressure measurement chamber via the pressure supply path.

[0017] It is preferable that the work base is provided with a plurality of the pressure measurement chambers, so that air leak inspections can be performed on a plurality of workpieces at the same time. [Effects of the Invention]

[0018] As described above, the air leak inspection tool of the present invention can reduce the time required for air leak inspection without using an expensive air leak tester. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a vertical cross-sectional view showing a state in which a workpiece is placed on an air leak inspection jig according to one embodiment of the present invention, as viewed from the side. FIG. [Figure 2] 2 is a vertical cross-sectional view showing a state in which the pressure device starts to pressurize the workpiece in the air leak inspection jig of FIG. 1. FIG. [Figure 3]2 is a longitudinal cross-sectional view showing how the piston slides via the work base when pressure is applied to the work in the air leak inspection jig of FIG. 1, thereby reducing the pressure in the pressure generation chamber and, ultimately, the pressure measurement chamber. FIG. [Figure 4] FIG. 2 is a perspective view of the workpiece and packing shown in FIG. 1. [Figure 5] FIG. 5 is a vertical cross-sectional view of the workpiece shown in FIG. 4. [Figure 6] FIG. 10 is a perspective view showing a conventional air leak inspection jig installed in a pressure device. [Figure 7] FIG. 7 is a partial cross-sectional perspective view of the air leak inspection jig of FIG. 6. DETAILED DESCRIPTION OF THE INVENTION

[0020] Next, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. Figures 1 to 3 show how a workpiece A made of an antenna connector is inspected using an air leak inspection jig 100 and a pressure device B according to one embodiment of the present invention.

[0021] (Work A) The workpiece A to be inspected in this embodiment is the antenna connector for the wireless device described above. As shown in Figure 4, the workpiece A is expected to have leak paths L1, L2 passing between the outer tube A1, core wire A2, resin layer A4, and adhesive layer A5. Therefore, the part of the workpiece A that is closer to the adhesive layer A5 than the flange A3 constitutes the inspection target area A6, and the surface of the flange A3 that faces the inspection target area A6 constitutes the sealing surface A7 that surrounds the inspection target area A6. However, the workpiece A to be inspected by the air leak inspection jig 100 of the present invention is not limited to this.

[0022] (Pressure device B) The pressure device B used in this embodiment is the same as the pressure device described above. More specifically, the pressure device B includes a lifting base B1 that moves up and down by manually operating a rotary handle (not shown), a plurality of pressure shafts B2 (only one of which is shown in FIG. 1) that hang down from the lifting base B1, and a jig mounting plate B3 on which the air leak inspection jig 100 is placed. The pressure shaft B2 includes a shaft head B21 and a coil spring B22, and slides in a sliding hole B11 of the lifting base B1 as the coil spring B22 expands and contracts.

[0023] (Air leak inspection jig) The air leak inspection jig 100 mainly comprises a work base 10 on which the work A is set, a piston cylinder 20 that generates pressure to be supplied to the work base 10, a pressure supply path 4 that connects the work base 10 and the piston cylinder 20, and a pressure sensor 5 that detects air leaks in the work A.

[0024] 1, the work base 10 is made of a metal plate-like member with horizontal upper and lower surfaces, and is provided with a plurality of (for example, five) pressure measurement chambers 1, 1, ... that open to the upper surface 11. The work base 10 has a rectangular shape that is long in the depth direction of FIG. 1, and is provided with a plurality of pressure measurement chambers 1, 1, ... in the depth direction.

[0025] The pressure measurement chamber 1 is formed in the shape of a flattened cylinder with a bottom and an axial direction aligned vertically to accommodate the inspection target portion A6 of the workpiece A. The pressure measurement chamber 1 communicates with the pressure sensor 5 via a pressure measurement port 14 that opens into a side surface 12 on the front side of the workpiece base 10 (right side in FIG. 1), and communicates with the pressure supply path 4 via a pressure intake port 15 that opens into a side surface 13 on the rear side of the workpiece base 10 (left side in FIG. 2). The multiple pressure measurement chambers 1, 1, ... are independent of one another and each have their own pressure measurement port 14 and pressure intake port 15.

[0026] The upper surface 11 of the work base 10 is provided on a horizontal flat surface, and a packing accommodating chamber 11a (corresponding to the "periphery of the pressure measurement chamber" in the claims) having approximately the same shape as the sealing surface A7 of the work A is provided around the periphery of the pressure measurement chamber 1, and a packing 3 (see FIG. 4) having approximately the same shape as the sealing surface A7 of the work A is accommodated therein. Note that the reference numeral 3a in FIG. 4 denotes a through hole that accommodates the outer tube A1 on the side of the inspection target portion A6 of the work A.

[0027] The piston cylinder 20 includes a piston 21 and a cylinder 22, and is mounted and fixed on a jig mounting board B3 of the pressurizing device B with the piston 21 on the upper side and the cylinder 22 on the lower side, with the sliding direction of the piston 21 in the vertical direction. The number of piston cylinders 20 provided is the same as the number of pressure measurement chambers 1.

[0028] Piston 21 has a flat cylindrical piston head 21a at its lower tip, and a piston rod 21b extending upward from piston head 21a. Cylinder 22 has a cylindrical inner chamber 22a whose axial direction is vertical, and a guide hole 22c that penetrates top wall 22b and guides piston rod 21b.

[0029] A piston base 23, which has a rectangular plate shape that is substantially the same as the work base 10 in plan view, is detachably fixed with screws to the upper end of the piston rod 21b ("one side" in the claims). The piston base 23 is also fixed to the work base 10 with screws, and the piston 21 is connected to the work base 10 via the piston base 23. When pressure is applied to the work base 10 from above ("one side" in the claims), the piston 21 slides downward together with the work base 10.

[0030] 3, when the piston head 21a descends, a pressure formation chamber 22d is formed above the piston head 21a (on the piston rod 21b side) in the inner chamber 22a of the cylinder 22. The pressure formation chamber 22d communicates with the pressure supply path 4 through a pressure supply port 22f that opens to a side surface 22e on the far side of the cylinder 22.

[0031] The pressure supply path 4 is made of a flexible resin pipe material, one end of which is connected to the pressure intake port 15 of the work base 10 and the other end of which is connected to the pressure supply port 22f of the cylinder 22, thereby connecting the pressure measurement chamber 1 and the pressure formation chamber 22d.

[0032] As the piston head 21a slides downward, the pressure formation chamber 22d expands its volume by sucking in air ("fluid" in the claims) from the pressure measurement chamber 1 through the pressure supply path 4, creating a negative pressure in the pressure formation chamber 22d and the pressure measurement chamber 1. A pipe air filter 41 is provided in the pressure supply path 4 to prevent dust from entering the inspection chamber and entering the pressure supply path 4 via the pressure measurement chamber 1 from entering the cylinder 22.

[0033] The pressure sensor 5 can be, for example, a piezo-resistance type sensor, and a pressure-sensitive element is exposed to the pressure measurement port 14 to measure the negative pressure supplied from the pressure measurement port 14. The pressure measured by the pressure sensor 5 is displayed on the monitor C. If the pressure measured by the pressure sensor 5 fluctuates within a predetermined time, a control unit (not shown) displays on the monitor C that there is an air leak in the work A.

[0034] (Air leak inspection method and the function and effect of each part) When performing an air leak inspection of workpiece A using air leak inspection jig 100, first, as shown in Fig. 1, lifting base B1 of pressurizing device B is raised to open the top surface 11 of workpiece base 10. In this state, workpiece A is set in each of the multiple pressure measurement chambers 1, 1, ... with the inspection target portion A6 of workpiece A accommodated in pressure measurement chamber 1 and the sealing surface A7 of workpiece A abutting against the packing 3 surrounding pressure measurement chamber 1. Here, since pressure measurement chamber 1 is provided so as to open upward on top surface 11 of workpiece base 10, workpiece A can be set from above, making it easy to set workpiece A.

[0035] After placing the workpiece A on the workpiece base 10, the rotary handle of the pressure device B is operated to lower the pressure shaft B2, and as shown in Fig. 2, the shaft head B21 of the pressure shaft B2 is brought into contact with the upper end of the workpiece A, and the shaft head B21 presses the workpiece A from above, and further presses the periphery of the pressure measurement chamber 1 on the upper surface 11 of the workpiece base 10 via the sealing surface A7 formed by the underside of the flange A3 of the workpiece A, via the packing 3. This seals the pressure measurement chamber 1 from the outside air.

[0036] 3, when the pressure shaft B2 is lowered and pressure is applied to the work base 10 from above via the work A, the work base 10 and the piston base 23 descend together. The piston 21 slides downward together with the piston base 23, and the piston head 21a moves downward within the inner chamber 22a of the cylinder 22, causing the pressure formation chamber 22d, which is the space above the piston head 21a, to expand in volume, creating a negative pressure in the pressure formation chamber 22d. The negative pressure created in the pressure formation chamber 22d is supplied to the pressure measurement chamber 1 via the pressure supply path 4. In this way, with the air leak inspection jig 100 of this embodiment, by applying pressure to the sealing surface A7 of the work A from above, the pressure measurement chamber 1 can be sealed and simultaneously placed under a negative pressure.

[0037] At this time, as the pressure measurement chamber 1 and the pressure formation chamber 22d approach each other in the vertical direction, the pressure supply path 4 is formed by folding back into a U-shape from a flexible resin tube, so the pressure supply path 4 deforms to narrow both ends of the U-shape, maintaining communication between the pressure measurement chamber 1 and the pressure formation chamber 22d.

[0038] Furthermore, because negative pressure can be created in the pressure measurement chamber 1 simply by lowering the piston 21 with the pressurizing device B in this way, an inexpensive pressure sensor 5 that does not include an air pump can be used instead of an expensive air leak tester that measures the pressure after evacuating the pressure measurement chamber 1 with an air pump, and a pressure sensor 5 can be provided individually for each of the multiple pressure measurement chambers 1, 1, .... Therefore, the air leak inspection jig 100 according to this embodiment eliminates the need to identify a work A that has an air leak from among the works A inspected simultaneously, which was necessary with the conventional inspection jig 900 that connects all the pressure measurement chambers 1, 1, ... and measures the pressure in only one pressure measurement chamber 1.

[0039] The pressure measurement chamber 1 is maintained at a negative pressure for a predetermined time, during which time the pressure in the pressure measurement chamber 1 is measured by a pressure sensor 5. The multiple pressure measurement chambers 1, 1, ... are each individually connected to a pressurizing device B, and when a pressure change exceeding a predetermined amount is detected, only the monitor C connected to the failed work A displays a failure of the inspection.

[0040] Furthermore, each part of the air leak inspection jig 100 is unitized. Specifically, the work base 10 is fixed to the piston head 21a, the piston base 23 to the piston 21, and the piston cylinder 20 to the jig mounting plate B3 of the pressure device B with screws, so each part can be easily removed. This allows the work base 10 to be replaced with a different work base 10 used for a different work A. Furthermore, each part can be easily replaced in the event of a malfunction.

[0041] As described above, the air leak inspection jig of the present invention is not limited to the above-described embodiment. For example, workpiece A may not be an antenna connector, but may be a device for inspecting leaks between the inside and outside of a workpiece, such as the beverage can described in Patent Document 1. The pressure measurement chamber may be located on the underside of the work base instead of the top, and the piston cylinder may be located above the work base to pressurize the work base and piston from below. The pressure measurement chamber may be located on the side of the work base, and a piston may be located on the opposite side of the work base with its axis horizontal, so that the work base and piston are pressurized horizontally from the opposite side. The piston base may be omitted, and the work base may be directly connected to the piston. The pressure supply path may be, for example, a passage drilled in the work base or piston rod. The pressure supply path may be a metal bellows pipe instead of a resin pipe, and an air filter may not be provided. A single pressure measurement chamber may be used.

[0042] Furthermore, the fluid filled in the pressure formation chamber 1 is not limited to air, but may be other gases such as nitrogen or hydrogen, or may be liquids such as water or oil. [Explanation of symbols]

[0043] Air leak inspection jig 100 Work Base 10 Pressure measurement chamber 1 Packing accommodation chamber 11a (around the pressure measurement chamber) Piston Cylinder 20 Piston 21 Piston head 21a Piston Base 23 Cylinder 22 Inner room 22a Pressure forming chamber 22d Pressure device 3 Pressure supply path 4 Pressure Sensor 5 Air filter 6 Work A Pressure device B

Claims

1. An air leak inspection jig for an air leak inspection targeting a workpiece having a sealing surface surrounding an inspection target portion of an air leak inspection, the inspection target portion being accommodated in a pressure measurement chamber of a workpiece base having a pressure measurement chamber opening on one side, and pressurizing the workpiece with a pressure device to press the sealing surface against a periphery of the pressure measurement chamber of the workpiece base, thereby sealing the pressure measurement chamber, a piston rod on the one side and a piston head on the other side opposite to the one side; one side of the piston rod is connected to the other side of the work base, and the pressure device presses the work base from the one side via the sealing surface of the work, causing the piston to slide together with the work base; a cylinder that slidably accommodates a piston head of the piston; a pressure generating chamber which is a space on one side or the other side of the piston head in the internal chamber of the cylinder, and which generates pressure by pressurizing or depressurizing the fluid in the internal chamber of the cylinder as the piston slides; a pressure supply passage that connects the pressure measurement chamber and the pressure generation chamber; a pressure sensor for measuring the pressure in the pressure measurement chamber; An air leak inspection jig comprising:

2. 2. The air leak inspection jig according to claim 1, wherein the one side is an upper side.

3. 2. The air leak inspection jig according to claim 1, wherein the piston rod has a piston base on the one side, and the work base is detachably connected to the piston base.

4. 3. The air leak inspection jig according to claim 1, wherein the pressure supply path is made of a flexible tube.

5. 5. The air leak inspection jig according to claim 4, wherein an air filter is provided in the pressure supply path.

6. 2. The air leak inspection jig according to claim 1, wherein the work base comprises a plurality of the pressure measurement chambers.

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