JP2010065739A - Sealing structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealing structure having improved sealing performance while integrally modularizing a synthetic resin housing with a rubber gasket and integrally fastening it to another housing. <P>SOLUTION: The sealing structure is provided for both combined portions of the first and second housings 1, 2 to be fastened and combined with each other. The second housing 2 is a synthetic resin molded product including a flange portion 21 to be fastened and combined with the first housing 1. The flange portion has an annular frame member 5 as a synthetic resin molded product integrally fixed to one peripheral side portion 5a to form a space 25 between the flange portion and itself. The frame member has an integrated rubber annular gasket 6 on the face on the opposite side to a space forming site. When the second housing is integrally fastened to the first housing through the flange portion, the annular frame member and the annular gasket are mounted between both combined portions while being elastically deformed. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a seal structure in a combined portion of a synthetic resin housing and a counterpart housing that are fastened together.

In an internal combustion engine for automobiles and the like, many structural parts for fastening and joining two housings via a sealing member such as a gasket are incorporated (for example, see Patent Documents 1 to 5). Recently, synthetic resin parts (molded bodies) have been widely used as cylinder head covers in internal combustion engines, inlet water, outlet water, manifold piping members, and the like for weight reduction or cost reduction. Such a cylinder head cover and a housing such as a piping member are fastened to a cylinder head or the like as a counterpart housing by a fastening member such as a bolt, and a gasket is interposed between the two combined portions to seal between the two housings. Is done. The need to modularize the synthetic resin housing and the rubber gasket has also increased, and this modularized part is brought into an assembly plant such as an internal combustion engine, and is fastened to the counterpart housing with bolts or the like. It is said.
Japanese Utility Model Publication No. 62-155285 Japanese Utility Model Publication No. 3-47418 Japanese Utility Model Publication No. 6-12220 JP-A-11-223166 JP-A-2005-330920

  The modularized parts as described above are formed by inserting a pre-molded rubber gasket member into a mold having a predetermined shape and injecting a synthetic resin material into the mold to perform insert molding. By the way, in such insert molding, when the shape of the housing is complicated, the insert part (rubber gasket member) moves due to the flow pressure of the injected resin, and the gasket is not fixed and integrated at a predetermined position. It may become a factor to reduce the yield of the. In addition, since the housing as the support for the rubber gasket is made of synthetic resin, there is a limit to the fastening strength with respect to the counterpart housing. Therefore, if the rubber gasket sags, this is the sealing property between the combined parts. Will be reduced.

  In Patent Document 3, a front cover is constituted by a flange portion made of a metal material and a cover portion made of synthetic rubber, synthetic resin or the like, and an elastic body of the cover portion is extended to the flange portion to be integrated with the gasket. A front cover is disclosed. In this case, the gasket is clamped between the flange portion and the block portion by fastening the flange portion to the block portion with a bolt, thereby sealing between the front cover and the block portion. As described in this patent document, the flange portion and the cover portion are integrated by directly vulcanizing and bonding the cover portion to the flange portion, or by forming the flange portion and the cover portion in advance, and bonding the both with an adhesive. For example, it may be fixed integrally with a screw, or may be integrally fastened with a fastener. In the case of the vulcanization adhesion molding, the gasket is configured as a part of the cover portion, so that the gasket itself is not moved by the flow pressure of the injected resin as in the case of the insert molding described above. However, when the rubber gasket is vulcanized and molded separately from the cover portion and insert molded into the synthetic resin cover portion, there is a concern that the above-described problems due to the movement of the gasket may occur.

  In Patent Document 4, a seal member is mounted between annular flanges formed on the periphery of each opening of the manifold flange and the manifold housing, and the manifold is flanged to the manifold housing by fastening members (bolts). A manifold mounting structure for fastening is disclosed. The seal member includes a rigid annular support member and a rubber elastic packing bonded to the outer peripheral side of the support member. The seal member is press-fit between the annular stepped portions. The packing is in close contact with each peripheral wall. However, the seal member in this case has the packing integrally supported by the support member, but is configured as a separate member from the manifold and the manifold housing, and is not modularized in combination with any of these. Further, the packing is not compressed along the fastening direction of the fastening member, and therefore is qualitatively different from a seal structure that seals between the two housings by a reaction force accompanying fastening compression.

  The present invention has been made in view of the above circumstances, and is designed to be modularized by integrating a synthetic resin housing and a rubber gasket, and exhibits excellent sealing performance in an integrated state of fastening with a counterpart housing. The object is to provide a sealing structure.

The seal structure of the present invention is a seal structure in both the combined portions of the first and second housings that are combined by fastening, and the second housing is a flange portion as a tightened joint portion for the first housing. An annular frame member made of a synthetic resin molding is integrally fixed to the flange portion at one peripheral side portion so as to form a space between the flange portion and the flange portion. The annular frame member is integrally provided with a rubber annular gasket on a surface opposite to the space forming portion, and the second housing has the flange portion and is integrally fastened to the first housing. In this case, the annular frame member and the annular gasket are sandwiched between the combined portions with elastic deformation.
The annular frame member and the flange portion of the second housing are integrally fixed by ultrasonic welding or laser welding.

In the present invention, the annular gasket may be formed integrally with the annular frame member. This molding integration includes a method of resin molding an annular frame member by inserting a pre-molded rubber annular gasket into a predetermined part in the mold, and inserting a pre-molded synthetic resin annular frame member. A method of vulcanizing and molding a rubber annular gasket, a method of simultaneously molding (two colors) a synthetic resin and a rubber material in a mold, or the like is employed.
In the present invention, an elastic member may be interposed between the annular frame member and the flange portion.

  According to the seal structure of the present invention, the second housing made of a synthetic resin molded body and the rubber gasket are integrated with each other through the frame member and modularized. Parts can be brought into an assembly factory and integrated with the first housing, which can meet the needs of modularization. Further, since the annular frame member made of a synthetic resin molded body is integrally fixed on one circumferential side portion so as to form a space between the flange portion, the other circumferential side portion of the annular frame member The side is a free end having elasticity unique to synthetic resin. Therefore, when the second housing is integrated with the first housing by using the flange portion, the other peripheral side of the annular frame member is connected to the first through the annular gasket. A reaction force accompanying the fastening is received from the united portion of the one housing, and is deformed by elasticity peculiar to the synthetic resin in the space with the fixing portion on the one peripheral side portion as a fulcrum. Further, the annular gasket is sandwiched between the annular frame member and the united portion of the first housing, and is compressed and elastically deformed with rubber elasticity.

  And since the composite restoring elasticity accompanying the elastic deformation of the annular frame member and the annular gasket acts between the annular gasket and the merged portion of the first housing, there is a gap between the merged portions in the first and second housings. It is very well sealed. In particular, since the second housing is made of synthetic resin, the combined pressure of the annular gasket and the first housing can be increased despite the fact that the fastening pressure cannot be increased as compared with a rigid body such as metal. A sufficient surface pressure is ensured between the united portions. In addition, the fastening pressure is dispersed and absorbed by the elasticity of the annular frame member and the annular gasket, so that the stress applied to the annular gasket is relieved and the sag of the rubber material is suppressed. Even if a sag occurs in the annular gasket, the annular frame member follows the sag due to its restoring property and compensates for this, so that a good sealing property can be maintained for a long time.

  When the annular gasket is formed integrally with the annular frame member, even if the overall shape of the second housing is complicated, the annular frame member itself may have a shape that follows the shape of the flange portion. In addition, since there is no great difference in size with the annular gasket, the insert molding with the rubber annular gasket, two-color molding, etc. are less affected by the mutual fluid pressure and are molded with high accuracy. . Accordingly, an integrated body of the annular gasket and the annular frame member can be obtained with a high yield.

  When an elastic member is interposed between the annular frame member and the flange portion, the combined elastic elasticity of the elastic gasket is further strengthened by further adding the elastic elasticity of the elastic member, and the combined portion of the annular gasket and the first housing Due to the increased surface pressure between the two, the sealing performance is further improved. In addition, the sag mitigating effect of the rubber gasket and the sag followability when sag occurs are further promoted and the seal life is more effectively extended.

  The best mode for carrying out the present invention will be described below with reference to the drawings. FIG. 1 is a longitudinal sectional view of an essential part showing an embodiment of the seal structure of the present invention, FIGS. 2 and 3 are other embodiments corresponding to the X part in FIG. 1, and FIG. b) shows another embodiment, (a) is the same state as FIG. 2 which shows the state before fastening, (b) shows the state after fastening, respectively.

  FIG. 1 shows a state in which a cylinder head cover (second housing) 2 made of a synthetic resin is fastened with a bolt (fastening tool) 3 to a cylinder head (first housing) 1 in an automobile internal combustion engine and combined. Show. The cylinder head cover 2 includes a cover main body 20 and an outward flange portion 21 formed integrally with the outer peripheral portion of the cover main body 20, and the flange portion 21 serves as a tightened joint portion with the cylinder head 1. Bolt insertion holes 22 are provided through the flange portion 21 at appropriate intervals along the circumferential direction, and a metal sleeve 4 is fitted in the inner hole of the bolt insertion hole 22. The cylinder head cover 2 includes a cover body 20 and a flange portion 21 and is manufactured by integral molding of synthetic resin. At the time of molding, the sleeve 4 is arranged at a predetermined position in the mold and insert molding is performed. It is united. The sleeve 4 is integrated with the flange portion 21, and its axial length is set so that the upper end is flush with the upper end surface of the flange portion 21 and the lower end protrudes slightly below the lower end surface 21 a of the flange portion 21. Has been. The inner diameter of the sleeve 4 is slightly larger than the outer diameter of the threaded portion 30 of the bolt 3 so that the threaded portion 30 can be inserted. A female screw portion 10 that can be screwed with the screw portion 30 is formed at a location corresponding to the bolt insertion hole 22 of the cylinder head 1.

  An annular notch step portion 23 is formed on the inner peripheral lower corner of the flange portion 21 over the entire circumference. Further, an attachment step 24 of the annular frame member 5 is formed at the base of the cover body 20 in the notch step 23. The annular frame member 5 is a cross section composed of an annular upright portion 5a on the inner peripheral side (one peripheral side portion) and an annular laterally extending flange piece 5b extending from the lower end of the upright portion 5a to the outer peripheral side. It consists of an integral molding of a generally bowl-shaped synthetic resin. The annular frame member 5 is integrally fixed to the mounting step portion 24 of the flange portion 21 by ultrasonic welding or laser welding at the upper end portion of the upright portion 5a. The upper end portion of the upright portion 5a and the mounting step portion 24 are integrally fixed without any slight gap therebetween. In this integrally fixed state, a space 25 that allows upward elastic deformation of the annular frame member 5 is formed between the notch step portion 23 of the flange portion 21 and the annular frame member 5.

  A rubber annular gasket 6 embeds the protruding base portion 6a on the lower surface (surface opposite to the formation portion of the space 25) of the side portion of the lateral flange portion 5b that is close to the outer peripheral side (free end side). It is made into one in the state made to enter. As described above, the annular frame member 5 and the rubber annular gasket 6 are integrated by inserting the pre-molded rubber annular gasket 6 into a predetermined portion in a mold (not shown). A resin molding method, a pre-molded synthetic resin annular frame member 5 is inserted and a rubber annular gasket 6 is vulcanized, or a synthetic resin and a rubber material are molded simultaneously (two colors). Made by etc.

  In the part product in which the cylinder head cover 2 and the annular frame member 5 integrally provided with the rubber gasket 6 are integrally fixed as described above, as shown in a two-dot chain line in FIG. The piece 5b extends from the upright part 5a at an obtuse angle, the outer peripheral part (the other peripheral side part) side of the lateral flange part 5b hangs down, and the annular gasket 6 projects from the lower end surface 21a of the flange part 21. Has been. In this state, it is brought into an assembly factory for an internal combustion engine and assembled to the cylinder head 1. That is, the modularized parts are placed on the cylinder head 1 so that the flange portion 21 is placed on the upper end portion (the combined portion of the cylinder head 1) 1a of the cylinder head 1. Since the annular gasket 6 protrudes from the lower end surface 21 a of the flange portion 21 as described above, the annular gasket 6 first comes into contact with the upper end portion 1 a of the cylinder head 1 in this placing process. In this state, the annular gasket 6 is elastically deformed according to the load due to the weight of the parts, and the outer peripheral side of the laterally extending flange piece 5b becomes a free end, and the upper end portion of the upright portion 5a and the mounting step portion 24 are provided. The annular frame member 5 having elasticity unique to the synthetic resin is elastically deformed upward in the space 25 with the fixed portion as a fulcrum.

  Then, when the bolt 3 is inserted into the inner hole portion of each sleeve 4 and the screw portion 30 of the bolt 3 is screwed into the female screw portion 10 of the cylinder head 1, the notch step portion 23 of the flange portion 21 and the cylinder head 1. The annular frame member 5 and the annular gasket 6 are sandwiched between the upper end portions 1a of the first and second elastic deformations, and the elastic deformation is further promoted. The lower end of the sleeve 4 abuts on the upper end portion 1 a of the cylinder head 1, the washer 32 (or the flange integrated with the head portion 31) 32 fitted to the screw portion 30 of the bolt 3, and the upper end portion 1 a of the cylinder head 1. In the state in which the sleeve 4 is tightly joined between the bolts, the screw fastening with the bolt 3 is completed. In this way, by fitting the sleeve 4 in the bolt insertion hole 22 in the above positional relationship, an excessive fastening pressure is not applied to the flange portion 21 made of synthetic resin, and the flange portion 21 is caused by the fastening pressure. It is possible to prevent damage or the like from occurring.

  When the tightened coupling body of the cylinder head cover 2 to the cylinder head 1 by the bolt 3 is completed, as shown in FIG. 1, the annular frame member 5 and the annular gasket 6 are as shown by the solid line position from the initial state indicated by the two-dot chain line. It is sandwiched between the notch step portion 23 of the flange portion 21 and the upper end portion 1a of the cylinder head 1 while being elastically deformed. In this sandwiched state, the annular frame member 5 is deformed by the elasticity unique to the synthetic resin, and the annular gasket 6 is deformed by the rubber elasticity, and each is maintained in a state of having a restoring elasticity. Therefore, a surface pressure in which these restoring elastic forces are combined acts between the annular gasket 6 and the upper end portion 1 a of the cylinder head 1, and this portion is suitably sealed by this surface pressure. Leakage of oil etc. is prevented.

  Then, as described above, the fastening pressure by the bolt 3 is dispersed and absorbed by the annular frame member 5 and the annular gasket 6 having elasticity, whereby the stress applied to the annular gasket 6 is alleviated and the rubber material is heavier. Is suppressed. Even if the annular gasket 6 sags, the annular frame member 5 follows the sag, and good sealing performance can be maintained for a long time.

  2 and 3 show another embodiment of the present invention, which is characterized in that an elastic member is interposed between the frame member 5 and the flange portion 21 in addition to the above-described embodiment. In the example of FIG. 2, an annular disc spring 7 is provided over the entire circumference of the frame member 5. Further, in the example of FIG. 3, the compression coil springs 8 are interposed in the circumferential direction of the frame member 5 in an appropriately arranged state at intervals. These disc springs 7 or compression coil springs 8 serving as elastic members are elastically compressed between the notch step portion 23 of the flange portion 21 and the frame member 5 when the cylinder head cover 2 is fastened to the cylinder head 1 as described above. The combined resilience is further strengthened and the surface pressure between the annular gasket 6 and the upper end 1a of the cylinder head 1 is reinforced. Therefore, the sealing performance of this portion is further improved, the sag mitigating effect of the annular gasket 6 and the sag followability when sag occurs are further promoted, and the life of the seal can be extended.

  2 and 3 exemplify the disc spring 7 or the compression coil spring 8 as the elastic member. However, the elastic member is not limited thereto, and has a restoring property such as a leaf spring, rubber, resin, or rubber foam. It is possible to use an elastic body instead of these. Since the other configuration is the same as that of the example shown in FIG. 1, the same reference numerals are given to the common parts and the description thereof is omitted.

  4 (a) and 4 (b) show still another embodiment, and show that the shape of the annular frame member 5 is slightly different from the above example. That is, as shown in FIG. 4A, the initial shape of the frame member 5 (the shape in the case where an external force such as fastening pressure is not applied) is approximately 90 ° with respect to the upright portion 5a. It is the shape extended to the outer peripheral side at an angle. Further, the lower portion of the annular gasket 6 projects downward from the lower end surface 21 a of the flange portion 21. When the cylinder head cover 2 configured in this way is fastened to the cylinder head 1 in the same manner as described above, the annular gasket 6 is elastically deformed and the laterally extending flange piece 5b is raised as shown in FIG. 4B. The annular frame member 5 and the annular gasket 6 are sandwiched between the flange portion 21 of the cylinder head cover 2 and the upper end portion 1a of the cylinder head 1 while being elastically deformed at an acute angle with respect to 5a. Therefore, the annular frame member 5 and the annular gasket 6 have the same functions as described above. In the case of this example, since the protruding amount of the annular gasket 6 from the lower end surface 21a of the flange portion 21 is small, an advantage of being excellent in the packing property and transportability of the parts as a product is added. Since other configurations are the same as described above, the same reference numerals are given to the common parts, and the description thereof is omitted here.

  In the above embodiment, the seal structure in the tightened joint portion between the cylinder head 1 and the cylinder head cover 2 in the internal combustion engine has been described as an example. However, the inlet water, the outlet water, the front cover, the manifold, etc., and other industries In a machine or the like, the seal structure of the present invention is applied even when a portion corresponding to at least one housing is made of a synthetic resin and a gasket is required to be integrated into a module in the synthetic resin housing. Can do. Further, in the above embodiment, the peripheral side portion on the inner peripheral side of the annular frame member 5 is fixed to the flange portion 21 and the peripheral side portion on the outer peripheral side is set as a free end. The side portion may be fixed to the flange portion 21 and the inner peripheral side peripheral portion may be a free end.

It is a longitudinal cross-sectional view of the principal part which shows one Embodiment of the seal structure of this invention. It is other embodiment, Comprising: It is a figure corresponding to the X section in FIG. It is the same figure as FIG. 2 which shows the modification of the embodiment. (A) (b) shows further another embodiment, (a) is the same figure as Drawing 2 which shows the state before conclusion, and (b) shows the state after conclusion, respectively.

Explanation of symbols

1 Cylinder head (first housing)
1a Upper end of cylinder head (merged part)
2 Cylinder head cover (second housing)
21 Flange part (merged part)
25 space 5 annular frame member 5a standing part (one circumferential side part)
6 Annular gasket 7 Disc spring (elastic member)
8 Compression coil spring (elastic member)

Claims (3)

It is a seal structure in both combined portions of the first and second housings combined by fastening,
The second housing is formed of a synthetic resin molded body including a flange portion as a tightening body portion for the first housing, and an annular frame member formed of a synthetic resin molded body is provided on the flange portion. The annular frame member is integrally provided with a rubber annular gasket on a surface opposite to the space forming portion, so that a space is formed between the annular frame member and the annular frame member.
When the second housing has the flange portion and is integrally fastened to the first housing, the annular frame member and the annular gasket are sandwiched between the combined portions with elastic deformation. A seal structure characterized by being configured to be worn. The seal structure according to claim 1,
The seal structure, wherein the annular gasket is formed integrally with the annular frame member. The seal structure according to claim 1 or 2,
An elastic member is interposed between the annular frame member and the flange portion.

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