JP7299147B2 - Sealing device for leak inspection - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seal device for detachably and airtightly closing an opening of a hollow part, and more particularly to a seal device for leak inspection used for closing the opening of a hollow part and conducting a leak test. It is.

Hollow parts that require airtightness, such as fuel delivery pipes, are metal pipes that feed fuel to injectors attached to the cylinder head of an internal combustion engine. The fuel delivery pipe includes a fuel inlet, optionally a fuel outlet, and a plurality of ejector cups, into which injectors are inserted during use. A plurality of injector cups and the like are manufactured by being attached to the pipe body of the fuel delivery pipe by brazing, and all of them are subjected to a leak test after manufacturing and before shipment.

In the leak test, the fuel supply port of the fuel delivery pipe, the fuel discharge port, and all the injector cups except for one of the plurality of injector cups are normally closed with a seal body, and the remaining one injector cup is inspected. Gas, for example, helium gas, is blocked by a seal body having a fluid passage inside for flowing inside the fuel delivery pipe, and in that state, the test gas is pressure-fed into the fuel delivery pipe in the chamber, and then a certain period of time. If the specified amount or more of the test gas has not leaked into the chamber after the lapse of time, the product is regarded as a product that has secured airtightness, and if the specified amount or more of the test gas has leaked into the chamber, It is regarded as a rejected product with insufficient airtightness.

For example, the seal structure disclosed in Patent Document 1 is well known, although it is not used for such a leak test.

JP-A-2007-57006

By the way, usually, a plurality of injector cups and the like are fixed to a fuel delivery pipe, which is a common pipe, by brazing as described above. Therefore, the positions of the plurality of injector cups vary within an allowable tolerance (for example, positional degree ±0.4). If there is variation in the positions of the multiple injector cups even within the allowable tolerance, the tip of the seal body (hereinafter also referred to as the “copying portion”) will be misaligned when the seal body is pushed into the injector cup. In this case, the inner peripheral surface of the injector cup may be damaged. Scratches on the inner peripheral surface of the injector cup cannot be overlooked because they may cause fuel leakage between the injector and the attached injector during use.

As a countermeasure for the above problem, it is conceivable to coat the copying portion of the seal body that contacts the inspection object with hard chrome plating or the like and polish it to make it difficult to scratch the inspection object. Eventually, the coating will come off, hindering smooth sliding and possibly damaging the inspection object. It is also conceivable that the copying portion of the seal body, which contacts the object to be inspected, is a part molded from a replaceable soft material such as resin or rubber. The production cost, replacement cost, etc. are required, and naturally the running cost is high.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems of the background art, and an object thereof is to propose a seal device for leak inspection which can be manufactured at low cost, whose performance is easily maintained, and which hardly damages an object to be inspected. That's what it is.

In order to achieve the above objects, the present invention provides a sealing device for leak inspection as described in the following [1] to [4].
[1] A seal device for leak inspection, comprising a seal body that seals the opening by being pushed into the opening of a hollow component, and a floating mechanism that supports the seal body in a displaceable manner, wherein the seal body includes: is provided with a sealing O-ring for sealing the opening when it is attached to the opening, and a front side of the portion where the sealing O-ring is provided is provided to the opening. A follow-up portion is formed that contacts the opening and guides the position and/or angle of the seal body in a direction to match the axial center of the opening when the sealing member is pushed in, and the follow-up portion moves toward the opening. A protective O-ring is provided which acts to prevent damage caused by the contact of the tracing portion with the opening when it is pushed in, and which does not contribute to the sealing of the opening when it is attached to the opening. A seal device for leak inspection, characterized in that:
[2] The seal device for leak inspection according to [1] above, wherein the protective O-ring is attached by being fitted into a concave groove formed in the copying portion of the seal body. .
[3] The above [1], wherein the hollow part is a fuel delivery pipe, and the opening is at least one of a fuel supply port, a fuel discharge port, and an injector cup provided in the fuel delivery pipe. Or the seal device for leak inspection according to [2].
[4] A seal device for leak inspection having the floating mechanism includes the seal body, a pressing body that presses the sealing body, a compression coil spring that biases the pressing body, a housing, and a lid, The seal body, the pressing body and the compression coil spring are housed in the housing in this order, and when the lid body is attached to the housing, the front portion of the seal body including the following portion and the O-ring for sealing can be used as a lid. The sealing device for leak inspection according to any one of [1] to [3] above, characterized in that it is assembled in a state of protruding outward from an opening formed in the body.

According to the sealing device for leak inspection according to the present invention described above, it includes a sealing body that seals the opening by being pushed into the opening of the hollow component, and a floating mechanism that supports the sealing body in a displaceable manner. The seal body is provided with a sealing O-ring that seals the opening when it is attached to the opening, and the opening is located in front of the portion where the sealing O-ring is provided. When the sealing member is pushed into the opening, a follower portion is formed that contacts the opening and guides the position and/or angle of the sealing member in a direction that matches the axis of the opening. Alternatively, the seal body supported so as to be displaceable by the floating mechanism will follow the shape of the opening to enter the inspection object that has variations in angle, such as the injector cup of the fuel delivery pipe. , the O-ring for sealing can be correctly positioned in the sealing portion of the opening. In addition, since the copying portion of the sealing body is provided with a protective O-ring that serves to prevent damage due to contact of the copying portion with the opening when the sealing body is pushed into the opening, the inspection can be performed. The presence of the protective O-ring enables sealing without damaging the inspection object when it is attached to the object or the like. In addition, since the protective O-ring provided in the profiling portion does not contribute to the sealing of the opening when it is attached to the opening, misjudgment due to double sealing and customer-specified A sealing device that does not cause inconvenience such as inspection in a sealed state other than a sealed portion. Furthermore, since the protective O-ring provided in the profiling portion of the seal body is inexpensive and easy to replace, the entire profiling portion is made of a replaceable soft material such as resin or rubber. The sealing device can be manufactured at a lower cost than the conventional method, and the performance can be easily maintained as compared with the case where the copying portion is coated with hard chrome plating or the like.

1 is an exploded perspective view showing an embodiment of a sealing device for leak inspection according to the present invention; FIG. FIG. 2 is a longitudinal sectional view of the seal device for leak inspection shown in FIG. 1; FIG. 4A is a view showing the sealing process of the opening of the injector cup of the fuel delivery pipe by the leak inspection sealing device according to the present invention, and (a) shows the initial positional relationship between the leak inspection sealing device and the opening of the injector cup; and (b) is a view showing a state in which the seal device for leak inspection is advanced and is about to be inserted into the opening of the injector cup. 4(a) is a diagram showing a next step of the process shown in FIG. 3, (a) is a diagram showing a state in which the seal device for leak inspection is further advanced and the seal body is set in the opening of the injector cup; ) is a diagram showing a state in which the seal device for leak inspection is pressed further to bring the seal body into pressure contact with the opening of the injector cup. FIG. 10A is a diagram conceptually showing another leak test sealing device according to the present invention, FIG. FIG. 3B is a diagram showing a state in which the device is about to be mounted in the opening, and FIG. 4B is a diagram showing a state in which the device is mounted in the opening.

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a sealing device for leak inspection according to the present invention will be described in detail below with reference to the drawings.

FIG. 1 is an exploded perspective view of a seal device for leak inspection according to the present invention developed as a seal device for leak inspection of a fuel delivery pipe. FIG. 2 is a longitudinal sectional view thereof.

The seal device 1 for leak inspection according to the present invention shown in FIGS. A protective O-ring 4 is provided. Further, the illustrated seal device 1 for leak inspection according to the present invention is configured as a seal device provided with a floating mechanism that supports the seal body 2 so as to be displaceable.

The sealing O-ring 3 provided in the sealing body 2 is in close contact with the sealing portion of the opening B in the state in which the sealing body 2 is attached to the opening B of the hollow part to be inspected. It serves to seal the opening B. Therefore, the material for the sealing O-ring 3 is preferably highly elastic and durable, such as nitrile rubber, fluororubber, silicon rubber, ethylene propylene rubber, and fluororesin. can be used.

The following portion A of the seal body 2 is formed in front of the portion where the O-ring 3 for sealing is provided, and when the seal body 2 is pushed into the opening B of the hollow part to be inspected, , guide the position and/or angle of the seal body 2, which is in contact with the opening B and supported by the floating mechanism so as to be displaceable, in a direction to coincide with the axis of the opening B. As shown in FIG. The protective O-ring 4 provided in the copying portion A functions to prevent damage due to contact of the copying portion A with the opening B, and when it is attached to the opening B, the opening B is protected. It does not contact part B and does not contribute to sealing. In order to achieve the functions and effects required of the protective O-ring 4, the wire diameter, diameter, etc. of the protective O-ring 4 are determined through various simulations according to the shape, dimensions, etc., of the object to be inspected. In the illustrated embodiment, a profiling portion A having a reduced diameter is formed on the front side of the seal body 2, and the profiling portion A is provided with a protective O-ring having a diameter smaller than that of the rear sealing O-ring 3. A ring 4 is provided. Due to the presence of this protective O-ring 4, when the sealing body 2 is pushed into the injector cup of the fuel delivery pipe to be inspected, the sealing body 2 follows the inner peripheral surface of the injector cup by the action of the tracing portion A. It is possible to prevent dents, scratches, etc. due to contact of the copying portion A when entering with a stick. In addition, since the protective O-ring 4 has a smaller diameter than the sealing O-ring 3 and does not contribute to sealing when attached to the injector cup, an erroneous determination due to double sealing may occur. Also, there is no inconvenience such as inspection in a sealed state other than the customer-specified sealed portion. As for the material of the O-ring 4, the same kind of material as that of the O-ring used as a normal seal may be used. However, from the actions and effects required for such a protective O-ring 4, the material for the protective O-ring 4 should be harder and more slippery than the elasticity required for an O-ring used as a normal seal. good. Therefore, it is preferable to select a material having a high hardness, such as nitrile rubber, ethylene propylene rubber, fluororubber, or urethane rubber.

As a method for attaching the O-ring 3 for sealing and the O-ring 4 for protection to the seal body 2, as shown in FIG. The grooves 10 and 11 may be attached by fitting the O-ring 4 for protection and the O-ring 3 for sealing, respectively. In particular, from the viewpoint of ease of replacement when worn, the method of attaching the protective O-ring 4 is preferably of the type in which it is fitted into the recessed groove 10 formed in the copying portion A of the seal body 2. The amount of fitting into the concave groove 10 is set for a normal seal from the viewpoint of the balance between mounting reliability and ease of replacement, and the above-described functions and effects required of the protective O-ring 4. It is desirable that the amount of protrusion is larger than that of the O-ring. The amount of protrusion is an amount that takes into consideration the deformation of the O-ring in addition to the amount that can cope with the deviation from the axis that occurs due to the tolerance of the object to be inspected. In the illustrated embodiment, since the floating mechanism is made flexible as described later, the amount of deformation of the O-ring may be assumed to be small. In order to reduce the risk that the O-ring for protection falls out of the groove due to friction, the groove 10 may be modified as follows. The groove into which the O-ring is fitted may be a semicircle matching the wire diameter of the O-ring. The accuracy of the semicircle may have an upper limit of +0.05 and a lower limit of -0. The bottom diameter of the concave groove may be 102 to 107% of the inner diameter of the O-ring, and the O-ring may be fitted while expanding. If it is necessary to increase the amount of protrusion of the O-ring from the groove, it is desirable to increase the wire diameter of the O-ring.

The floating mechanism itself, which displaceably supports the seal body 2 to which the sealing O-ring 3 and the protective O-ring 4 are mounted, is also used in an automatic sealing device, and various structures have been developed. . The purpose of the floating mechanism is to displaceably support the seal body 2 so that it can be correctly guided to the seal portion to be inspected, and the following three conditions are required at a minimum.
1. Ability to cope with relative positional deviation in the XY direction with the seal portion to be inspected.
2. It must be able to cope with the deviation of the seal part and the angle to be inspected.
3. After the position is determined, the seal part can be pressed down with a force that is strong against the reaction force of the inspection pressure and the repulsion of the O-ring.

In order to satisfy the conditions that the floating mechanism should have, the seal device 1 for leak inspection according to the present invention shown in FIGS. 1 and 2 has the following configuration.

In FIGS. 1 and 2, 2 is a seal body fitted with a sealing O-ring 3 and a protective O-ring 4 as described above, 5 is a pressing body for pressing the sealing body 2, and 6 is the pressing body. 5 is a compression coil spring, 7 is a housing, and 8 is a lid. The seal body 2, the pressing body 5 and the compression coil spring 6 are housed in the housing 7 in this order. The front portion 2a including the O-ring 4 for protection attached to the cover 8 and the O-ring 3 for sealing is assembled in a state of protruding outward from an opening 9 formed in the lid 8. As shown in FIG.

The front portion 2a of the seal body 2 is formed into three stages 2A, 2B, and 2C that decrease in diameter toward the front. The O-ring 4 for protection is fitted in the groove 4B, and the O-ring 3 for sealing is fitted in the groove 11 formed in the second step 4B as described above. The rear portion 2b of the seal member 2 is formed to have a smooth curved surface with no corners and a sidewardly enlarged diameter 12 so as not to protrude from the opening 9 of the lid member 8. As shown in FIG. A rear end surface 2c of the seal body 2 is formed as a smooth convex surface protruding rearward.

The pressing body 5 is formed in a substantially columnar shape and has a large movable range in the lateral direction and in the axial direction within the housing 7 . The diameter d of the pressing body 5 is designed to be smaller than the inner diameter D of the housing 7 . A clearance (Dd) between the pressing body 5 and the housing 7 is designed to be equal to or greater than the tolerance or variation of the product to be inspected. Also, the length l of the pressing body 5 is designed to be relatively short with respect to the inner length L of the housing 7 . The movable range of the pressing member 5 in the axial direction is designed to be greater than or equal to the stroke from when the sealing member 2 comes into contact with the product to when the guide by the copying portion A is completed. Further, the front end surface 5a of the pressing body 5 is formed into a smoothly recessed concave surface along the rear end surface 4c of the sealing body 4. As shown in FIG. A recess 13 for accommodating a part of the compression coil spring 6 is formed in the rear end face 5b of the pressing body 5. As shown in FIG.

The compression coil spring 6 is relatively loose so that the seal body 2 can swing smoothly with a weak force. When the seal body 2 is moved horizontally with respect to the inspection target, if the compression coil spring 6 is too loose, the gravity acting on the seal body 2 and the pressing body 5 causes the seal body to tilt and tilt against the seal portion to be inspected. don't face it. Therefore, it is preferable that the elastic force of the compression coil spring 6 is as small as possible to the extent that the seal body 2 can be pressed against the lid body 8 and the seal body 2 can face the seal portion. Also, in order to facilitate the movement of the seal body 2, it is advantageous that the spring diameter m of the compression coil spring 6 is as small as possible. However, when the seal body 2 is moved horizontally with respect to the object to be inspected, if the spring diameter m is too small, the seal body 2 tilts against the seal portion due to gravity in the initial state (see FIG. 3(a)). do not face each other. Therefore, considering the weight and movable range of the seal member 2 and the pressing member 5, it is preferable to reduce the spring diameter m within a range that does not greatly increase the spring force.

The housing 7 has a storage portion 7a and a base portion 7b. A male thread 14 is formed on the outer peripheral wall of the opening end of the storage portion 7a, and a through hole 15 for connecting a piston rod (not shown) is formed in the base portion 7b. is formed. A recess 16 for accommodating a portion of the compression coil spring 6 is formed in the rear wall of the storage portion 7a. In addition, the inner peripheral wall portion near the opening end of the storage portion 7 has an enlarged diameter 17, so that the movable range of the seal body 2 is expanded.

The lid 8 is formed with the opening 9 as described above, and is also formed with a female screw 18 that is screwed into the male screw 14 formed on the housing 7 . The inner peripheral surface of the opening 9 is tapered 19 to widen the movable range of the swing of the seal body 2 .

The seal device 1 for leak inspection according to the present invention is fixed to the fuel delivery pipe by, for example, brazing, and the installation position or installation angle of the injector cup opening B has variations even within the allowable tolerance range. Also, by mounting as follows, it is possible to achieve a highly reliable seal without damaging the opening B.

As an initial state, as shown in FIG. 3A, the opening B of the injector cup 51 of the fuel delivery pipe 50 set in the leak inspection device or the like is displaced from the axial center of the seal body 2 .

As shown in FIG. 3B, the sealing device 1 is moved forward with respect to the opening B of the injector cup 51 by a pressing mechanism such as a piston cylinder (not shown). Since the opening B is displaced from the axial center of the seal body 2, the tracing portion A of the seal body 2 contacts the inner peripheral surface of the opening B and enters the opening B following it.
At this time, in the seal device 1 according to the present invention, the protective O-ring 4 is attached to the tracing portion A of the seal body 2 supported by the floating mechanism so that the protective O-ring 4 can be displaced. Damage due to contact with the inner peripheral surface of the opening B is prevented. In addition, since the seal body 2 is supported by the floating mechanism that is easy to swing and has a large movable range, the seal body 2 follows the inner peripheral surface of the opening B and changes its position and angle. Enter smoothly while changing.

As the sealing device 1 is further moved forward, the position and angle of the sealing body 2 are determined, and the axial center is aligned with the opening B as shown in FIG. 4(a).
In the operation up to this point, the force applied to the seal body 2 is only the weak force of the compression coil spring 6 applied via the pressing body 5, and the seal body 2 is not pushed in by an unreasonable force. There is no further damage such as scratches to the.

Subsequently, when the sealing device 1 is pressed further, the compression coil spring 6 is fully compressed, and as shown in FIG. The thrust of the mechanism is directly transmitted to the seal body 2 via the pressing body 5, and the sealing O-ring 3 provided in the seal body 2 is pressed against the seal portion of the opening B, realizing a highly reliable seal. be done.
At this time, since the protective O-ring 4 does not contribute to the sealing, there is no problem such as erroneous determination due to double sealing or inspection of the sealed state at a location other than the customer-designated sealing portion.

Although the embodiments of the seal device for leak inspection according to the present invention have been described above, the present invention is not limited to the above-described embodiments at all, and the scope of the present invention as a technical idea described in the scope of claims. Of course, various modifications and changes are possible within.
For example, in the above embodiment, the seal device for leak inspection according to the present invention, which was developed as a seal device for leak inspection of a fuel delivery pipe, was described as a specific example. Needless to say, it can be applied to seal openings of joints, valves, pipes used as piping, and the like.
As shown in FIG. 5, the sealing device for leak inspection according to the present invention in the case where it is necessary to seal by coming into contact with the outer peripheral surface of the opening B, like a pipe as a pipe, has a seal body 2 which is a pipe. A recessed portion 20 having a profiling portion A with an enlarged diameter is formed on the tip end side into which the opening B of is inserted, and a large diameter protective O-ring is formed on the inner peripheral surface of the profiling portion A with the enlarged diameter 4 is mounted, a small-diameter sealing O-ring 3 is mounted behind it, and the sealing body 2 is displaceably supported by the floating mechanism as described above.

According to the present invention, it is possible to provide a sealing device that can be manufactured at a low cost and whose performance is easily maintained, and that does not damage the object to be inspected. It can be widely used as an inspection sealing device.

1 seal device for leak inspection 2 seal body 2a front part of seal body 2b rear part of seal body 2c rear end face of seal body 2A, 2B, 2C stepped part formed in seal body whose diameter is reduced toward the front 3 O for sealing Ring 4 O-ring for protection 5 Pressing body 5a Front end face of pressing body 5b Rear end face of pressing body 6 Compression coil spring 7 Housing 7a Storage portion of housing 7b Base of housing 8 Lid 9 Opening 10, 11 Groove 12 Expanded diameter 13 Recess 14 Male screw 15 Through hole 16 Recess 17 Expanded diameter 18 Female screw 19 Taper 20 Recess 50 Fuel delivery pipe 51 Injector cup A Copying part B Opening

Claims (4)

A seal device for leak inspection, comprising: a seal body that seals the opening by being pushed into the opening of a hollow component; and a floating mechanism that supports the seal body in a displaceable manner, the seal body comprising A sealing O-ring is provided to seal the opening when it is attached to the opening. A tracing portion is formed that contacts the opening and guides the position and/or angle of the seal body in a direction to match the axis of the opening. is provided with a protective O-ring that acts to prevent damage due to contact of the tracing portion with the opening and does not contribute to sealing of the opening when attached to the opening. A seal device for leak inspection, characterized by: 2. The seal device for leak inspection according to claim 1, wherein said protective O-ring is attached by being fitted into a concave groove formed in said copying portion of said seal body. 3. The method according to claim 1, wherein the hollow component is a fuel delivery pipe, and the opening is at least one of a fuel supply port, a fuel discharge port, and an injector cup provided in the fuel delivery pipe. seal device for leak inspection. A seal device for leak inspection having the floating mechanism includes the seal body, a pressing body that presses the seal body, a compression coil spring that biases the press body, a housing, and a lid body, and the seal body. , the pressing body and the compression coil spring are housed in the housing in this order, and when the lid is attached to the housing, the front portion of the sealing body including the following portion and the O-ring for sealing is formed in the lid. 4. The seal device for leak inspection according to claim 1, wherein the seal device is assembled in a state of protruding outward from the formed opening.

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