JP2007024097A - Leakage inspecting device and leakage inspecting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To inspect the presence or absence of leakage in a cylinder body formed by welding a lower cap or closing an bottom end by closing process. <P>SOLUTION: In a leakage inspecting method, a change in a supply amount or pressure in gas supplied in a cylinder body 1 is detected while supplying gas in the cylinder body 1 in which an head end 1b is airtightly closed with a bottom end 1a closed. A leakage inspecting device is provided with an inflow pipe 10 facing to the inside of the cylinder body 1, a closing means 20 for airtightly closing the head end 1b of the cylinder body 1 with a base end 11 of the inflow pipe 10 airtightly closed, and a supply detecting means 30 which is connected to the closing means 20 so as to supply gas into the cylinder body 1 through the inflow pipe 10 and which detects a change in a supply amount or pressure in gas supplied in the cylinder body 1. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a leakage inspection method and a leakage inspection device, and more particularly, to a leakage inspection method and a leakage inspection device for a cylinder body that constitutes a hydraulic shock absorber with a bottom end closed by welding of a lower cap or by a closing process. .

  For example, in a hydraulic shock absorber mounted on a vehicle, it is connected to the vehicle wheel side using a knuckle bracket held at the bottom end of a cylinder body constituting the hydraulic shock absorber. Patent Document 1 discloses a proposal that also serves as welding at the bottom end of the cylinder body in a welding operation when holding the knuckle bracket at the bottom end portion of the cylinder body.

  That is, Patent Document 1 discloses a proposal for integrally connecting a so-called lower end of a knuckle bracket, a bottom end of a cylinder body arranged inside the knuckle bracket, and a lower cap that closes the bottom end by welding. Has been.

  Therefore, there is no problem as long as the above welding is performed as set and leakage of the bottom end of the cylinder body is prevented as well as holding of the knuckle bracket, but there is also an aspect that is difficult to be absolutely welded. Preferably, a leak inspection is performed on the cylinder body.

On the other hand, as what can perform the performance inspection in the cylinder body, for example, there is a proposal disclosed in Patent Document 2, and according to this, leakage in the shaft seal portion in the cylinder body can be inspected by using a fluid. In particular, the leakage inspection can be performed by replacing the shaft seal portion in the bottom portion of the cylinder body with a welded portion with respect to the lower cap.
JP 2000-356238 A (paragraphs 0007 and 0008 in the specification, FIG. 4) Japanese Patent Laying-Open No. 2004-52983 (Claims 1, Paragraph 0008 in the specification, FIG. 1)

  However, in the proposal disclosed in Patent Document 2 described above, since the leakage of the shaft seal portion is inspected, the fluid used for this inspection is liquid, that is, in many cases, hydraulic fluid. become.

  That is, in the leak inspection of the shaft seal portion having a seal member or the like, even if the same fluid is used, it becomes meaningless if gas is used. Therefore, it is natural to use liquid, and from this, it is disclosed in Patent Document 2 described above. Even in the proposal, hydraulic oil is used for leak inspection.

  However, since not only hydraulic fluid but also liquid has surface tension, it may block even a hole through which gas passes. Therefore, leakage inspection is performed on the cylinder body that constitutes the hydraulic shock absorber. Therefore, it is meaningless to perform an inspection using a fluid as disclosed in Patent Document 2.

  The present invention was created in view of such a situation, and the object of the present invention is to check whether there is leakage in the cylinder body formed by welding the lower cap or closing the bottom end by closing. It is an object of the present invention to provide a leakage inspection method and a leakage inspection apparatus that are optimal for enabling the above-described inspection and expecting improvement in versatility.

  In order to achieve the above object, the configuration of the leakage inspection method according to the present invention basically includes supplying gas into a cylinder body in which the bottom end is closed while the head end is closed in an airtight state, and the cylinder It is assumed that a change in supply amount or a change in pressure in the gas supplied into the body is detected.

  The configuration of the leakage inspection apparatus according to the present invention is basically the same as the leakage inspection apparatus for inspecting the presence or absence of leakage in the cylinder body whose bottom end is closed. A closing means for closing the head end of the cylinder body in an airtight state while holding the base end portion of the pipe in an airtight state, and gas can be supplied to the cylinder body through the inflow pipe connected to the closing means. And a supply detecting means for detecting a change in supply amount or pressure in the gas supplied into the cylinder body.

  Therefore, according to the leak inspection method of the present invention, gas is used as the fluid. For example, unless a special gas such as nitrogen gas is selected, the atmosphere can be used as it is, and there is a concern about the lack of working fluid. Needless to say, when the fluid is a liquid, it is possible to detect a leak due to a so-called pinhole that may be blocked by the surface tension of the liquid.

  According to the leak inspection apparatus of the present invention, the opening at the head end of the cylinder body is closed in an airtight state by the closing means, and is supplied from the supply detection means via the inflow pipe held by the closing means. By detecting a change in the supply amount of the gas or a change in the pressure of the supplied gas by the supply detection means, it is possible to detect a leak in the cylinder body.

  At this time, since gas is selected as the fluid to be supplied into the cylinder body, it is necessary to discharge the liquid from the cylinder body when the liquid is used as the fluid after the closing means and the inflow pipe are withdrawn at the end of the inspection. Compared to the above, the use of gas is advantageous in that it does not require an operation of exhausting the gas from the cylinder body.

  Also, since gas is selected as the fluid supplied to the cylinder body, compared to the case where a so-called pinhole is blocked by surface tension and leakage cannot be detected because it is a liquid that is a concern when using liquid. There is an advantage that leakage due to pinholes can be detected, and unless a special gas such as nitrogen gas is selected, the atmosphere can be used as it is, and there is an advantage that there is no need to worry about lack of working fluid.

  Hereinafter, the leakage inspection method and the leakage inspection apparatus according to the present invention will be described based on the illustrated embodiment. First, the leakage inspection method according to the present invention is closed at the bottom end 1a with reference to FIG. While the gas as a fluid is supplied into the cylinder body 1 in which the head end 1b is closed in an airtight state, the supply amount of the gas supplied into the cylinder body 1 is changed, or the pressure of the supplied gas is changed. It is supposed to detect changes.

  Therefore, in the leak inspection method according to the present invention, since gas is used as a fluid, when the fluid is a liquid, even if it is a so-called pinhole that may be clogged by the surface tension of the liquid. Leakage due to holes can be detected.

  In the leak inspection method according to the present invention, since gas is used as a fluid, the atmosphere can be used as it is unless a special gas such as nitrogen gas is selected. Unless there is an atmosphere in which dust is floating, there is no need to worry about the lack of working fluid.

  Further, in the leak inspection method according to the present invention, since gas is used as the fluid, the cylinder body 1 is used when the liquid is used as the fluid after the closing means 20 and the inflow pipe 10 are withdrawn at the end of the inspection. Compared with the fact that an operation for discharging the liquid from the cylinder body 1 is required, the operation for discharging the gas from the cylinder body 1 is not required by using the gas.

  Incidentally, the cylinder body 1 to be inspected for leakage by the leak inspection method and the leak inspection apparatus according to the present invention constitutes, for example, a hydraulic shock absorber mounted on a vehicle, and in the illustrated case, prior to the inspection. The bottom end 1a is previously closed by welding of the lower cap 1c.

  In the illustrated cylinder body 1, the knuckle bracket 2 is held on the outer periphery of the bottom end portion 1d. At this time, the lower end 2a of the knuckle bracket 2 is connected to the bottom end 1a of the cylinder body 1 and the bottom end. It is said that it is welded together at the time of welding for integrally connecting the lower cap 1c for closing 1a.

  Since the present invention intends to inspect the cylinder body 1 for leaks, the leak is not shown in place of the leak caused by welding of the lower cap 1c to the bottom end 1a. Of course, leak inspection can also be practiced for leaks resulting from the closing process on the end 1a.

  In the illustrated embodiment, the cylinder body 1 has a spring receiver 3 for the suspension spring on the outer periphery on the head end side. However, in the practice of the present invention, the spring receiver 3 is not provided. Of course.

  Based on the above assumptions, the leak inspection apparatus according to the present invention that embodies the above-described leak inspection method includes an inflow pipe 10, a closing means 20, and a supply detection means 30, as shown in FIG. In the illustrated example, the holding means 40 is provided.

  The inflow pipe 10 is present in the cylinder body 1, and in many cases, the inflow pipe 10 is disposed so as not to interfere with the inner periphery of the cylinder body 1 while being disposed in the shaft core portion.

  And in this inflow pipe 10, the base end part 11 used as the upper end part in the figure is held by the closing means 20 described later, and has a through-hole 12 penetrating therethrough in the shaft core part. It is going to be.

  Incidentally, in the inflow pipe 10, the main body portion 13 resident in the cylinder body 1 can reduce the amount of gas supplied into the cylinder body 1 by the mode of the cylinder body 1 for inspecting leakage. The length and diameter are selected.

  The closing means 20 closes the head end 1b of the cylinder body 1 in an airtight state while holding the base end portion 11 of the inflow pipe 10 in an airtight state, and connects a supply detection means 30 described later. .

  At this time, as shown in the figure, the closing means 20 closes the head end 1b of the cylinder body 1 in an airtight state while holding the base end portion 11 of the inflow pipe 10 in an airtight state, and It has the seal part 21 which obstruct | occludes the head end 1b in an airtight state, This seal part 21 is hold | maintained to the holder part 22 which hold | maintains the base end part 11 of the inflow pipe 10 substantially, for example so that isolation | separation is possible. It is supposed to be done.

  Incidentally, the seal part 21 is detachably held by the holder part 22 in order to allow replacement when the seal part 21 is continuously used and deteriorates. Of course, any configuration can be selected for the configuration of the holder portion 22 and the separable configuration of the seal portion 21 with respect to the holder portion 22 as long as the replacement of the holder portion 22 is possible and easy.

  The supply detection means 30 makes it possible to supply gas into the cylinder body 1 via the inflow pipe 10 held by the closing means 20 and supply amount in the gas supplied into the cylinder body 1. Or a change in pressure in the gas supplied into the cylinder body 1 can be detected.

  Therefore, although not specifically illustrated, a supply unit that can supply a gas may have a free configuration, and a change in the amount of gas or a change in pressure in the cylinder body 1 is detected. As a means for enabling the above, a free configuration may be adopted.

  As for the holding means 40, as shown in the drawing, the receiving portion 41 that keeps the cylinder body 1 standing and the closing means 20 are held and the seal portion 21 is pressed against the head end 1 b of the cylinder body 1. It is supposed that it has the press part 42 to do.

  At this time, since the length of the cylinder body 1 varies, the cylinder body 1 can be moved up and down, that is, can be moved so as to correspond to the length, and the pressing portion 42 is also movable. In the closing means 20 described above, in view of the repeated seating of the sealing portion 21 on the head end 1b of the cylinder body 1, it can be moved up and down in the drawing, that is, can be moved.

  In view of the above, the holding means 40 is arbitrary as long as the cylinder body 1 and the closing means 20 provided adjacent to the cylinder body 1 can be maintained in a fixed state and the cylinder body 1 can be replaced. It may be configured as

  Since the leak detection device according to the present invention formed as described above embodies the leak detection method according to the present invention, the same function and effect as in the case of the leak detection method described above can be obtained. Will play.

  That is, the supply amount of the gas supplied from the supply detection means 30 via the inflow pipe 10 held by the closing means 20 in the cylinder body 1 in which the opening at the head end 1b is closed in an airtight state by the closing means 20. By detecting the change or the change in the pressure of the supplied gas by the supply detection means 30, it is possible to detect a leak in the cylinder body 1.

  At this time, since the fluid supplied into the cylinder body 1 is a gas, when the liquid is used as the fluid after the closing means 20 and the inflow pipe 10 are withdrawn at the end of the inspection, Compared with the fact that an operation for discharging the liquid from the cylinder body 1 is required, the operation for discharging the gas from the cylinder body 1 is not required by using the gas.

  In addition, since gas is selected as the fluid supplied into the cylinder body 1, compared to the case where a so-called pinhole is blocked by surface tension and leakage cannot be detected because the liquid is a concern when using the liquid. In addition, there is an advantage that leakage due to pinholes can be detected, and unless a special gas such as nitrogen gas is selected, the atmosphere can be used as it is, and there is no need to worry about lack of working fluid. .

It is a longitudinal cross-sectional view which shows the leak detection apparatus which embodies the leak inspection method by this invention with a cylinder body.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cylinder body 1a Bottom end 1b Head end 1c Lower cap 1d Bottom end part 2 Knuckle bracket 2a Lower end 3 Spring receiver 10 Inflow pipe 11 Base end part 20 Closure means 21 Seal part 30 Supply detection means

Claims (5)

Leakage characterized by supplying gas into the cylinder body in which the bottom end is closed while the head end is closed in an airtight state, and detecting a change in supply amount or pressure in the gas supplied into the cylinder body Inspection method The leak inspection method according to claim 1, wherein the bottom end of the cylinder body is closed by welding of a lower cap or by closing processing. In a leak inspection apparatus for inspecting the presence or absence of leakage in a cylinder body having a closed bottom end, a cylinder body head while holding an inflow pipe existing in the cylinder body and a base end portion of the inflow pipe in an airtight state Closing means for closing the end in an airtight state, and supply of gas into the cylinder body through the inflow pipe connected to the closing means, and change in supply amount or pressure in the gas supplied into the cylinder body Leakage inspection apparatus comprising supply detection means for detecting The leak inspection apparatus according to claim 3, wherein the bottom end of the cylinder body is closed by welding of a lower cap or by closing processing. 4. The leak inspection apparatus according to claim 3, wherein the closing means closes the opening at the head end of the cylinder body in an airtight state and has a seal portion adjacent to the outer periphery of the proximal end portion of the inflow pipe in the airtight state.

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