JP2008215582A - O ring and its twist detecting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an O ring and its twist detecting method for allowing a user to confirm an installation state of the O ring, even when the O ring is installed in a fitting part of an installation object member fitted to a fitting object part. <P>SOLUTION: This O ring 34 is installed in a groove part 27 formed on the outer periphery of the fitting part 23 fitted to the fitting object part 19 in a base member 12. An annular magnet 35 is embedded in the O ring 34. After installing the O ring 34, the installation state of the O ring 34 is confirmed by detecting the direction of a magnetic pole of the magnet 35 in the O ring 34 over the peripheral direction. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an O-ring and its twist detection method.

In a tank for storing high-pressure gas such as a high-pressure hydrogen tank, a seal is an important member for maintaining airtightness. Then, leakage in a packing (for example, an O-ring) at such a gas-tight portion is detected as a strain sensor that detects the distortion of the packing, a pressure sensor that detects the pressure of the gas, or a high frequency generated by minute gas leakage. There is a technique of detecting using an AE sensor (see, for example, Patent Documents 1 to 3).
JP-A-8-28711 Japanese Patent Laid-Open No. 9-125465 JP-A-9-112701

  On the other hand, when the O-ring is assembled to the member to be fitted to the fitted portion, the O-ring is twisted due to friction with the fitted portion when the fitted portion is fitted to the fitted portion. Sometimes. If such a twist occurs, the original performance of the O-ring cannot be fully exhibited, that is, the airtightness as a seal cannot be maintained. However, since the O-ring is covered with the fitting portion and the fitted portion after fitting, it is difficult to confirm the twist.

  The present invention has been made in view of such circumstances, and confirms the assembled state of the O-ring even when the O-ring is assembled to the fitting portion of the member to be assembled to be fitted to the fitted portion. An object is to provide a possible O-ring and a method for detecting its twist.

  If the O-ring is twisted, the original performance of the O-ring may not be sufficiently exhibited. Further, for example, hydrogen leakage may occur under low temperature conditions (for example, about −50 ° C.) in a high-pressure hydrogen tank. Furthermore, the leak check (gas leak inspection) cannot measure such a low-temperature leak or a leak when the O-ring deteriorates. The best way to avoid these is to directly measure the torsion of the O-ring, but heretofore there has been no such method.

  In order to achieve such an object, the method for detecting twisting of an O-ring according to the present invention includes assembling an O-ring embedded with a magnet in the groove portion of an assembly target member in which a groove portion is formed on the outer periphery of the fitting portion, The fitting portion is fitted to the fitting portion, the direction of the magnetic pole of the magnet in the O-ring is detected in the circumferential direction, and the twist of the O-ring is confirmed after assembling. According to such a method, the torsion occurring in the O-ring can be detected by detecting the direction of the magnetic pole of the magnet in the O-ring. Thereby, even when it is a case where it assembles | attaches to the fitting part of the assembly | attachment object member fitted to a to-be-fitted part, the assembly | attachment state of an O-ring can be confirmed.

  Further, in the method of detecting twisting of the O-ring, the O-ring is moved by moving the azimuth magnet close to the assembled O-ring and moving in the circumferential direction to detect the direction of the pointer of the azimuth magnet. You may detect the direction of the magnetic pole of an inner magnet over the circumferential direction.

  Further, in the torsion detection method of the O-ring, the magnet is brought close to the assembled O-ring and moved along the circumferential direction, and the repulsive force or attractive force acting on the magnet is detected, You may detect the direction of the magnetic pole of the magnet in an O-ring over the circumferential direction.

  Further, in the method of detecting twisting of the O-ring, the electric wire is caused to approach the assembled O-ring and moved along the circumferential direction while passing a predetermined value of current so that the electric wire is generated by a magnet. The direction of the magnetic pole of the magnet in the O-ring may be detected in the circumferential direction by detecting the force received from the magnetic field and the direction thereof.

  In the O-ring twist detection method, an annular magnet may be used as the magnet.

  In the O-ring twist detection method, a plurality of magnets arranged in an annular shape may be used as the magnet.

  In the method for detecting twisting of the O-ring, the fitted part may be a high-pressure tank, and the fitting part may be a base fitted into the high-pressure tank.

  Further, the present invention is an O-ring assembled to a groove formed on the outer periphery of a fitting portion of an assembly target member to be fitted to the fitted portion, and a magnet for detecting twist of the O-ring is embedded. It is that.

  According to the present invention, the assembly state of the O-ring can be confirmed even when the O-ring is assembled to the fitting portion of the assembly target member that is fitted to the fitted portion.

  Hereinafter, an O-ring and a twist detection method thereof according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 shows a liner (member to be fitted) 11 and a cap member (assembly) that are components of a gas tank (for example, a hydrogen supply tank in a fuel cell system) for filling and storing a high-pressure gas (for example, hydrogen gas) inside. 2, and the base member 12 is attached to the mouth portion 13 formed on one side of the liner 11 in the axial direction as shown in FIG. 2. Here, although not shown, the gas tank having the liner 11 and the base member 12 is configured by reinforcing the outside of the liner 11 made of, for example, a synthetic resin, to which the metal base member 12 is attached, with a fiber reinforced resin layer. Is.

  The liner 11 has a cylindrical body portion 15, a bottom portion 16 formed so as to close one end side in the axial direction of the body portion 15, and the distance from the body portion 15 to the axial direction opposite side of the body portion 15 in the axial direction. A shoulder 17 formed to have a reduced diameter, and an inner side that extends while being inclined so as to be located on the inner side of the liner 11 from the inner end edge of the shoulder 17 toward the central axis, as shown in FIG. An extending portion 18 and a cylindrical fitted portion 19 projecting into the liner 11 along the axial direction of the liner 11 from the opposite side of the shoulder portion 17 of the inner extending portion 18. The inside of the fitted portion 19 is a mouth portion 13. An insert ring 20 for tightening the O-ring 34 is fitted to the outer periphery of the mouth portion 13.

  The base member 12 has a through-hole 21 having a constant diameter in the center, a mouth flange portion 22 formed at one end in the axial direction, and a substantially cylindrical fitting portion 23 formed at the other end in the axial direction. The gap between the mouth flange portion 22 and the fitting portion 23 is a first taper portion 24 whose diameter increases as the mouth flange portion 22 side is separated from the mouth flange portion 22, and the fitting portion 23 side extends from the fitting portion 23. It is set as the 2nd taper part 25 which becomes a large diameter, so that it leaves | separates. Here, the base member 12 is attached to the liner 11 by fitting the fitting portion 23 into the fitted portion 19 by press fitting until the second tapered portion 25 contacts the inner extending portion 18.

In the present embodiment, the cylindrical fitting portion 23 is formed with a groove portion 27 extending in the circumferential direction on the outer peripheral side thereof.
In the groove portion 27, two synthetic resin backup rings 32 and 33 having a rectangular cross section are fitted side by side in the axial direction on the rear side in the press-fitting direction into the mouth portion 13. An O-ring 34 made of rubber such as EPDM (ethylene propylene diene terpolymer) is fitted on the front side in the press-fitting direction.

  As shown in FIGS. 4A and 4B, the O-ring 34 has a ring-shaped magnet 35 embedded in the central portion of the cross section over the entire circumference. The magnet 35 has an S-pole on one side in the axial direction of the O-ring 34 and an N-pole on the other side.

  Next, a case where the O-ring 34 is assembled will be described.

  First, the backup ring 32, the backup ring 33, and the O-ring 34 are fitted into the groove portion 27 of the base member 12 in order from the rear side in the press-fitting direction to the mouth portion 13 to form a sub-assembly. At this time, the O-ring 34 is assembled so that, for example, the N pole of the magnet 35 is on the rear side in the press-fitting direction and the S pole is on the front side in the press-fitting direction.

  Then, the base member 12 is attached to the liner 11 by press-fitting the fitting portion 23 into the fitting portion 19 until the second taper portion 25 contacts the inner extension portion 18, and then the outer periphery of the mouth portion 13. The insert ring 20 is press-fitted and the O-ring 34 is tightened.

  When the fitting part 23 is fitted to the fitted part 19, the O-ring 34 sub-assembled to the base member 12 moves relative to the fitted part 19 in the axial direction while being in contact with the fitted part 19. A frictional force is received from the portion 19. For this reason, in some cases, twisting may occur.

  However, as described above, since the ring-shaped magnet 35 is embedded in the central portion of the cross section of the O-ring 34 over the entire circumference, the O-ring 34 is checked by confirming the direction of the magnetic pole of the magnet 35. It can be easily determined whether or not is assembled without twisting.

Here, a method for determining the twist of the O-ring 34 will be described.
(Torsion confirmation method using a compass)
As shown in FIG. 5, the azimuth magnet 40 is placed directly below the O-ring 34 (or directly above, in short, in the vicinity of the O-ring 34 along the axial direction) with respect to the O-ring 34 disposed in the groove 27. Move them along the circumferential direction.
Thereby, for example, when the pointer 40a of the azimuth magnet 40 is maintained over the circumferential direction with the N pole upward and the S pole downward, it is determined that there is no twist, and when the pointer 40a is tilted, it is twisted. It can be determined that there is.

(Torsion check method using magnet)
As shown in FIG. 6, the magnet 41 is moved close to the O-ring 34 so as to face the O-pole 34 disposed in the groove 27 so as to face the same pole, and moved along the circumferential direction. A change in the magnitude of the repulsive force acting on the magnet 41 is detected.
If the repulsive force is substantially constant over the circumferential direction, it is determined that there is no twist, and if there is a change in the repulsive force over the circumferential direction, it can be determined that there is a twist.
Note that a change in the magnitude of the attractive force acting on the magnet 41 at that time may be detected by making the opposite pole face the O-ring 34 and moving it along the circumferential direction.

(Twist confirmation method using electric wire)
As shown in FIG. 7, the electric wire 42 is moved along the circumferential direction while passing a predetermined value of current i through the electric wire 42 perpendicular to the O-ring 34 disposed in the groove 27. The force F received from the magnetic field generated by the magnet 35 at that time and the direction thereof are detected.
If the force F received from the magnetic field in the circumferential direction and the direction thereof are substantially constant, it is determined that there is no twist, and if there is a change in the circumferential direction, it can be determined that there is a twist.

  According to this embodiment described above, even if the O-ring 34 is assembled to the groove portion 27 of the base member 12 and the fitting portion 23 is press-fitted into the fitted portion 19 of the liner 11, it is embedded in the O-ring 34. By detecting the direction of the magnetic pole of the magnet 35 in the circumferential direction, it is possible to confirm whether or not the O-ring 34 is twisted even after the cap member 12 is attached. Accordingly, the assembly failure of the O-ring 34 can be suppressed, and the sealing performance of the O-ring 34 can be ensured.

  In the above embodiment, the case where the O-ring 34 is assembled to the fitting portion 23 of the base member 12 fitted to the fitted portion 19 of the liner 11 of the gas tank has been described as an example. Various other members such as assembly of O-rings to pressure or temperature monitoring sensors (members to be assembled) fitted and fitted to fitting holes in a part of the valve body (fitting part) The present invention can be applied to the assembly of the O-ring to each other, and in any case, the same effect as described above can be obtained.

  In the above embodiment, the structure in which the O-ring 34 is assembled together with the backup rings 32 and 33 in the one groove 27 formed in the fitting portion 23 has been described as an example. In addition to the groove portion 27 that is assembled, another groove portion may be formed on the rear side in the fitting direction to the mouth portion 13, and another O-ring made of, for example, butyl rubber may be assembled to the groove portion.

  In the above-described embodiment, the ring-shaped magnet 35 is embedded in the central portion of the cross section of the O-ring 34. However, this is only a preferred example of the magnet 35 formed continuously. As another example, the divided magnets 35 may be continuously formed so as to be embedded in the O-ring 34 at equal intervals. However, also in this case, the magnets 35 are arranged so that the magnetic fields are in the same direction. Further, when the ring-shaped magnet 35 is used as in this embodiment, it is preferable that the magnet is made of a material or a shape that can be expanded and contracted from the viewpoint of detecting the twist of the O-ring 34.

It is a disassembled perspective view of a liner and a base member. FIG. 2 is an assembly diagram of the liner and the base member shown in FIG. 1. It is sectional drawing which shows the structure of the O-ring which concerns on embodiment of this invention. It is a figure which shows O-ring attached to a nozzle | cap | die member, Comprising: (a) is a top view, (b) is sectional drawing. It is a figure explaining the method to detect the state of the magnet in an O-ring with a compass. It is a figure explaining the method to detect the state of the magnet in an O-ring with a magnet. It is a figure explaining the method to detect the state of the magnet in an O-ring with an electric wire.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Liner (member to be fitted), 12 ... Cap member (member to be assembled), 19 ... Fitting portion, 23 ... Fitting portion, 27 ... Groove portion, 34 ... O-ring, 35 ... Magnet, 40 ... Direction Magnet, 40a ... pointer, 41 ... magnet, 42 ... electric wire.

Claims (8)

  An O-ring in which a magnet is embedded is assembled in the groove portion of the assembly target member in which a groove portion is formed on the outer periphery of the fitting portion, the fitting portion is fitted into the fitted portion, and the magnet in the O-ring A method for detecting twist of an O-ring in which the orientation of the magnetic pole of the O-ring is detected in the circumferential direction and the twist of the O-ring is confirmed after assembly.   By moving the azimuth magnet close to the assembled O-ring and moving it in the circumferential direction, and detecting the direction of the pointer of the azimuth magnet, the direction of the magnetic pole of the magnet in the O-ring extends in the circumferential direction. The method for detecting twisting of an O-ring according to claim 1 to detect.   By moving a magnet close to the assembled O-ring and moving it in the circumferential direction, and detecting the repulsive force or attractive force acting on the magnet, the direction of the magnetic pole of the magnet in the O-ring is changed. The method for detecting torsion of an O-ring according to claim 1, wherein detection is performed over a direction.   The electric wire is brought close to the assembled O-ring and moved along the circumferential direction while passing a current of a predetermined value, and the force that the electric wire receives from the magnetic field generated by the magnet and its direction are detected. The twist detection method of the O-ring according to claim 1, wherein the direction of the magnetic pole of the magnet in the O-ring is detected in the circumferential direction.   The method for detecting twisting of an O-ring according to any one of claims 1 to 4, wherein an annular magnet is used as the magnet.   The O-ring twist detection method according to any one of claims 1 to 4, wherein a plurality of magnets arranged in an annular shape are used as the magnets.   The O-ring twist detection method according to any one of claims 1 to 6, wherein the fitting portion is a high-pressure tank, and the fitting portion is a base fitted into the high-pressure tank.   An O-ring that is assembled in a groove formed on the outer periphery of a fitting portion of a member to be assembled that fits into a fitting portion, and in which an O-ring twist detection magnet is embedded.

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