JP5147066B2 - Sealing structure - Google Patents

Description

  The present invention includes a first member made of a synthetic resin molded body, a fastening member integrated with the first member by insert molding, and a second member fastened to the first member via the fastening member. It is related with the sealing structure in the fastening part by.

Recently, in automobile engines and the like, synthetic resin molded bodies have been widely used as engine parts and the like in order to reduce weight and fuel consumption. Such synthetic resin moldings include cylinder head covers, radiator-related equipment, housing members such as oil pans, piping members, and the like. These members include, for example, screw parts for mounting oil control valves, water temperature sensors, and the like. An attaching screw portion, an oil plug attaching screw portion, or the like is integrally fixed by insert molding (see, for example, Patent Document 1 or 2).
JP-A-9-170855 Japanese Patent No. 4137019

  FIG. 6 shows a first member 100 as a housing member or a piping member made of a synthetic resin molded body, and a nut member (fastening member) 101 integrated with the first member 100 by insert molding. For example, the structure of the part which attached the 2nd member 102 as a water temperature sensor by screwing fastening is shown. In this mounting structure, when the second member 102 is a water temperature sensor, the detection portion 102 a is arranged so as to face the flow path of the detected medium in the first member 100. The nut member 101 has a female screw portion 101a formed on the inner peripheral portion thereof, and the first member 100 and the second member 102 are fastened and integrated by screwing the male screw portion 102b formed on the second member. When the second member 102 is screwed, an annular packing 102d is fitted under the flange portion 102c, and this packing 102d is placed between the flange portion 102c and the upper surfaces of the first member 100 and the nut member 101. The first member 100 and the second member 102 are fastened in a sealed state by compressing with the above. A plurality of knurled grooves 101b are formed in the outer peripheral portion of the nut member 101, and the synthetic resin constituting the first member 100 enters and hardens into the knurled grooves 101b during the insert molding. The first member 100 and the nut member 101 are firmly integrated by the engaging action of the portions.

  In the fastening state as described above, the sealed fastening state between the first member 100 and the second member 102 is achieved by the presence of the packing 102d. However, since the metal nut member 101 is inserted and formed integrally when the first member 100 is molded, it is inevitable that a minute gap is generated at the interface due to the difference in thermal expansion coefficient between the two. . Although the sealed state is achieved by the packing 102d, the medium that has entered the gap reaches the sealed portion by the packing 102d, leaks out of the sealed portion over time, and the sealed state cannot be maintained. Arise.

  In Patent Document 1, a seal ring is attached to a second metal part (insert member), and a sleeve made of a synthetic resin is attached to the outer peripheral surface of the second part so as to compress the seal ring. A pipe joint formed by injecting a thermoplastic resin compatible with a sleeve and integrally molding the first portion including the sleeve of the second portion is disclosed. In this case, since the first part is injection-molded in a state where the seal ring is compressed by the sleeve, the sealing performance between the first part and the second part is ensured, and the medium leaks from the pipe joint. It is said that it can be surely prevented. Incidentally, in Patent Document 1, the nut member 101 and the second member 102 fastened to the nut member 101 shown in the example of FIG. 6 are the second portion and the second pipe, but the sleeve and the seal ring are the same. The second portion and the sealing performance of the fastening portion of the second pipe are not involved at all. Therefore, if there is a gap between the first part and the second part due to the difference in thermal expansion coefficient between the first part and the second part, the sealing performance between the first part and the second part is Obviously, it is not covered by the fastening of the two tubes.

  Further, Patent Document 2 discloses that an oil control valve mounting sleeve of a synthetic resin cylinder head cover is integrated by insert molding when the cylinder head cover is molded (FIGS. 1 and 2 of the same document). See example). This sleeve is made of a metal material such as an aluminum alloy, and a primer is applied to the outer peripheral surface of the sleeve before insert molding, so that the synthetic resin constituting the cylinder head cover and the sleeve are firmly integrated. However, although it is firmly integrated by the primer, a gap is generated at the interface between the sleeve and the cylinder head cover due to the difference in the coefficient of thermal expansion, and it is expected that oil leaks over time. . In addition, the oil control valve is attached to the sleeve not by fastening but by fitting the spool housing, and the seal between the sleeve and the oil control valve is made by an O-ring attached to the spool housing. Therefore, this O-ring cannot prevent oil leakage due to a gap generated at the interface between the sleeve and the cylinder head cover.

  This invention is made | formed in view of the said situation, The fastening part of the 1st member which consists of a synthetic resin molded object, and the 2nd member fastened via the metal fastening member integrally provided by insert molding is provided. It aims at providing the sealing structure which has the function to seal, and the function to seal the mounting part of the fastening member with respect to a 1st member.

  The sealing structure according to the present invention includes a first member made of a synthetic resin molding, a metal fastening member integrated with the first member by insert molding, and fastened to the first member via the fastening member. The second member is a sealing structure in the fastening portion, and the first member and the fastening member are integrally formed by the insert molding in a state of being fitted to the outer peripheral portion of the fastening member. An annular gasket made of an elastic body is interposed, and at the time of fastening, the annular gasket is compressed in the fastening direction, whereby the first member and the second member are sealed. Rubber or elastomer is used as the elastic body constituting the annular gasket. The fastening member may be a nut member having a female screw portion or a tubular member having a male screw portion protruding to the second member side. In the former case, the second member has a male thread portion, and is inserted into the nut member and screwed and fastened. In the latter case, the second member has a female thread portion, and is fitted into the tubular member and fastened by screwing.

  In the present invention, a recess is formed at the outer peripheral portion of the fastening member and at the interface with the annular gasket, and a portion of the elastic body constituting the annular gasket is formed in the recess by the molding pressure at the time of the insert molding. It is good also as a state which entered with elastic deformation. In this case, a sink part due to the elastic deformation is formed in an outer peripheral part corresponding to the concave part of the fastening member in the annular gasket, and a part of the synthetic resin constituting the first member enters the sink part. It is good also as what is united.

  In the present invention, an annular chevron bead portion may be bulged at a portion of the annular gasket to which the fastening pressure is applied. The first member and the fastening member have an interface that directly merges, and a recess is formed at the interface of the fastening member, and a portion of the synthetic resin that constitutes the first member is engaged with the recess. It is good also as what is united.

  According to the sealing structure of the present invention, a metal fastening member is inserted and integrated with the first member made of a synthetic resin molded body when the first member is molded. Therefore, the second member can be fastened and integrated with the first member via the fastening member. Then, when the second member is fastened to the first member via the fastening member, the annular gasket is compressed in the fastening direction, thereby sealing the first member and the second member. Further, the annular gasket is made of an elastic body, and the first member and the fastening member are integrally formed by the insert molding in a state of being fitted to the outer peripheral portion of the fastening member. A space between the one member and the fastening member is sealed by the annular gasket. The fastening pressure also causes elastic deformation in the radial direction of the elastic body constituting the annular gasket, and thereby the sealing of the interface between the annular gasket and the fastening member and the interface between the annular gasket and the first member is ensured. . Moreover, even if a thermal strain occurs between the synthetic resin and the metal due to the difference in thermal expansion coefficient, the gasket interposed between the first member and the fastening member absorbs this, and the medium to be sealed leaks out. Such a gap is not generated, and an excellent sealed state is maintained for a long time.

  A concave portion is formed at the outer peripheral portion of the fastening member at the interface with the annular gasket, and a part of the elastic body constituting the annular gasket enters the concave portion with elastic deformation by the molding pressure at the time of the insert molding. In this state, the contact area between the annular gasket and the fastening member is increased, and the sealing performance of this portion is further improved. In this case, a sink portion due to the elastic deformation is formed in an outer peripheral portion corresponding to the concave portion of the fastening member in the annular gasket, but a part of the synthetic resin is caused by molding pressure during molding of the synthetic resin. Since it enters into the sink portion and is integrally cured, the joint area between the annular gasket and the first member is increased, and the sealing performance of this portion is further improved. Strong integration between the member and the annular gasket is also achieved.

  In the case where an annular chevron bead is raised at the portion of the annular gasket to which the fastening pressure is applied, the bead is compressed and elastically deformed, and the mutual surface pressure due to its restoring elasticity causes the sealing performance of the fastening part to be More improved. In addition, if the first member and the fastening member are provided with an interface where the first member and the fastening member are directly combined, and a recess is formed at the interface of the fastening member, a part of the synthetic resin enters the recess and is cured when the first member is molded. Therefore, the anchor effect of the engaged portion allows the first member and the fastening member to be firmly integrated and the fastening member to be fixed to the first member at a predetermined position with high accuracy. .

  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 a sealing structure of the present invention, and FIGS. 2A and 2B are procedures for insert molding a first member and a fastening member in the sealing structure by injection molding. (A) shows the state before injecting the synthetic resin, and (b) shows the injected state. 3 (a) and 3 (b) are partial cross-sectional views showing a modification of the initial shape of the annular gasket before molding in the same sealing structure, and FIGS. 4 and 5 are cross-sectional views of the main part in the sealing structure of another embodiment. is there.

  In FIG. 1, a first member 1 is a cylinder head cover as an engine part of a car, a radiator-related device, a housing member such as an oil pan, a piping member, and the like, and is made of a synthetic resin molding. Fastening members 2 such as an oil control valve mounting screw portion, a water temperature sensor mounting screw portion, or an oil drain plug mounting screw portion are integrally fixed to the first member 1 by insert molding. An annular gasket 3 made of an elastic material such as rubber or elastomer is integrally interposed in a part of the fixing portion between the fastening member 2 and the first member 1. The annular gasket 3 is integrated with the first member by insert molding together with the fastening member 2, and one end surface 3 a in the axial direction is exposed to the upper outside of the first member 1, and the end surface 3 a has a periphery thereof. An annular chevron bead portion 3b is formed so as to protrude along the direction.

  As the synthetic resin constituting the first member 1, PA (polyamide), PPA (polyphthalamide), PPS (polyphenylene sulfide), POM (polyacetal), and the like are desirably employed. In addition, as the elastic body constituting the annular gasket 3, rubbers such as H-NBR, NBR, EPDM, ACM, VMQ, FKM and FVMQ, or TPE (thermoplastic elastomer), TPAE (thermoplastic polyamide elastomer) and TPEE are used. An elastomer such as (thermoplastic polyester-based elastomer) is desirably employed. Furthermore, iron, brass, aluminum, etc. are illustrated as a metal material which comprises the fastening member 2. FIG.

  The fastening member 2 is a nut member having an internal thread portion 2a formed on the inner peripheral portion. The external thread portion 4a of the second member 4 such as an oil control valve, a water temperature sensor, or an oil plug is screwed into the internal thread portion 2a. As a result, the second member 4 is screwed to the first member 1 via the fastening member 2. In the illustrated example, the second member 4 is shown as a water temperature sensor. In this screwed and fastened state, the detection portion 4b faces the flow channel in the first member 1 and the temperature of the water flowing through the flow channel is detected. Made. A flange 4c is formed on the screw base of the second member 4, and the bead portion 3b of the annular gasket 3 is compressed by the fastening pressure in the L direction accompanying the screw fastening. Thus, a sealing structure between the second member 4 and the first member 1 is formed.

  Due to the presence of the annular gasket 3, the interface between the annular gasket 3 and the first member 1 and the interface between the annular gasket 3 and the fastening member 2 are surely sealed, and a sealing structure with an extremely excellent sealing performance as a whole is achieved. . In particular, the first part member 1 made of a synthetic resin molded body and the metal fastening member 2 are susceptible to thermal distortion due to the difference in coefficient of thermal expansion, but the annular gasket 3 made of an elastic body is between them. Since it exists, this thermal strain is absorbed by the annular gasket 3, thereby eliminating any concern about leakage of the medium (water) due to the generation of gaps over time.

  In the example shown in FIG. 1, a circumferential groove-shaped recess 2b is formed on the outer peripheral portion of the fastening member 2 and at the interface with the annular gasket, and the recess 2b is annularly formed by molding pressure at the time of the insert molding. It shows that a part 3c of the elastic body constituting the gasket 3 is in a state of entering with elastic deformation. Due to the concave / convex engagement relationship between the concave portion 2b and the ingress portion (part) 3c of the elastic body, the contact area at the interface between the two increases, thereby making the thermal strain absorption more effective. In addition, the sealing property is further improved, and further, the anchoring effect enables stable integration of both. In addition, a sink portion 3d that accompanies the elastic deformation is formed along the circumferential direction on the outer peripheral portion of the annular gasket 3 corresponding to the concave portion 2b of the fastening member 2, and is one of the synthetic resins constituting the first member 1. The part 1a enters the sink part 3d and is integrated. The contact area at the interface between the sink part 3d and the synthetic resin intrusion part (part) 1a is increased due to the integral engagement relationship between the sink part 3d and the seal part 3d. At the same time, the annular gasket 3 and the first member 1 are firmly integrated by the anchor effect.

  Furthermore, the first member 1 and the fastening member 2 are directly combined at the lower portion of the gasket 3, and three circumferential groove-shaped recesses 2c are formed at the interface of the combined portion of the fastening member 2, A part 1b of the synthetic resin constituting the first member 1 is engaged with and integrated with the recess 2c. Due to the anchor effect by the engagement and integration of the part 1b of the synthetic resin with the recess 2c, the first member 1 and the fastening member 2 can be firmly integrated, and the fastening member 2 with respect to the first member 1 can be firmly integrated. The position is fixed with high accuracy. Of course, the number of the recesses 2c and the cross-sectional shape thereof are not limited to those shown in the drawings.

  Next, the procedure for forming the first member 1 employed in the sealing structure by inserting the fastening member 2 and the annular gasket 3 will be described with reference to FIGS. As shown in FIG. 2A, a metal fastening member 2 in which an annular gasket 3 is fitted on the outer peripheral portion is disposed at a predetermined position of one split mold (lower mold in the illustrated example) 6 of the split mold 5. To do. A female screw portion 2a is formed in the inner peripheral portion of the fastening member 2, and the concave portion 2b and the concave portion 2c are formed in advance in the outer peripheral portion. On the other hand, the annular gasket 3 is prepared in advance by vulcanization molding or the like so as to have a square cross section and a shape having the bead portion 3b on the end face 3a. In the initial shape of the annular gasket 3 in this case, both sides of the rectangular cross section are straight and do not have any recesses or protrusions.

  Next, as shown in FIG. 2 (a), the other split mold (upper mold in the illustrated example) 7 is placed at a predetermined position and clamped, whereby the lower mold 6 and the fastening disposed on this are clamped. A cavity 5 a for forming a first member is formed between the member 2 and the annular gasket 3 and the upper mold 7. Then, a molten synthetic resin 10 is injected from an injection gate (not shown), and as shown in FIG. 2B, the synthetic resin 10 is injected into the cavity 5a and molded. By this injection molding, the first member 1 is integrally molded while the fastening member 2 and the annular gasket 3 are inserted. At this time, the injection pressure of the synthetic resin 10 is applied to the outer peripheral portion of the annular gasket 3. Due to the load of the injection pressure, a part 3c of the elastic body constituting the annular gasket 3 enters the recess 2b of the fastening member 2 with elastic deformation at the inner peripheral portion of the annular gasket 3. Accordingly, a sink portion 3d is formed at the outer peripheral portion of the annular gasket 3 and corresponding to the recess 2b, and a portion 1a of the synthetic resin 10 enters the sink portion 3d to be integrated. Moreover, in the site | part in which the recessed part 2c was formed, while a part of the synthetic resin 10 approached into the recessed part 2c, this part is made into the part where the 1st member 1 and the fastening member 2 unite directly. If the synthetic resin 10 is demolded after curing, an insert molded body in which the first member 1, the fastening member 2, and the annular gasket 3 are integrated is obtained as shown in FIG. When the synthetic resin 10 is cured, thermal strain (thermal shrinkage) occurs due to the difference in thermal expansion coefficient between the synthetic resin and the metal, but this thermal strain is absorbed by the presence of the annular gasket 3 made of an elastic body, A stable integrated structure of the three members (the first member 1, the fastening member 2, and the annular gasket 3) having no gap between them can be obtained. Further, when the synthetic resin 10 is cooled in the curing process, the first member 1 positioned on the outer diameter side of the annular gasket 3 and the fastening member 2 is reduced in diameter, and this reduction action makes the three members stronger. They are integrated and the sealing performance at each interface is further improved.

  3A and 3B show a modification of the initial shape of the annular gasket 3. In the example shown in (a), a circumferential groove-shaped recess 3e shallower than the sink part 3d formed after the insert molding is formed in advance on the outer peripheral part of the annular gasket 3 and corresponding to the recess 2b of the fastening member 2. Has been. By forming the concave portion 3e in advance, the elastic member part 3c constituting the annular gasket 3 at the time of the insert molding is entered into the concave portion 2b of the fastening member 2 and corresponding to this. The formation of the sink portion 3d is further promoted. Further, in the example shown in (b), a protrusion 3f having a bulk lower than the depth of the concave portion 2b is provided along the circumferential direction at a portion corresponding to the concave portion 2b of the fastening member 2 on the inner peripheral portion of the annular gasket 3. Pre-formed. By forming the protrusions 3f in advance, the part 3c of the elastic body constituting the annular gasket 3 at the time of the insert molding is further promoted with elastic deformation of the fastening member 2 into the recess 2b. The Further, by hooking the protrusion 3f on the recess 2b of the fastening member 2, the assembly of the annular gasket 3 to the fastening member 2 before molding is improved, and the molding can be performed easily and stably.

FIG. 4 shows another embodiment. In this embodiment, the end surface 3 a of the annular gasket 3 is a flat surface without the bead portion 3 b as described above, and the second member 4 (see FIG. 1) is connected to the end surfaces of the first member and the fastening member 2. It is formed so as to protrude to the fastening side. Also in this example, when the second member 4 is fastened to the fastening member 2 in the same manner as described above, the protruding portion of the annular gasket 3 is compressed, and the first member 1 and the first member 1 through the fastening member 2 are compressed in the same manner as described above. A sealing structure in the fastening portion with the two members 4 is formed.
Since other configurations are the same as those described above, the same reference numerals are given to the common portions, and descriptions thereof are omitted.

FIG. 5 shows yet another embodiment. In this embodiment, three circumferential groove-shaped recesses 2 d having a V-notch cross section are formed on the outer periphery of the fastening member 2. Each of the recesses 2d is in a state in which a part 3g of the elastic body constituting the annular gasket 3 has entered by the molding pressure at the time of insert molding in the same manner as described above, and the annular gasket 3 corresponding to each recess 2d. On the outer peripheral portion, a sink portion 3h accompanying this elastic deformation is formed in a cross-sectional wave shape. Then, a part 1c of the synthetic resin constituting the first member 1 enters the sink portion 3h in the same manner as described above and is integrated. The recessed portion 2d, the entry portion 3g, the sink portion 3h, and the entry portion 1c formed therewith are different in shape and number from the above example and have different sealing properties and engagement relations, but the function exerted by them. Are basically the same. Other formation modes can also be adopted, and these formation modes are appropriately selected and adopted in consideration of the properties of the elastic body constituting the annular gasket 3 and the properties of the synthetic resin constituting the first member 1.
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.

  As described above, the sealing structure of the present invention is desirably employed in an oil control valve mounting portion, a water temperature sensor mounting portion, or an oil plug mounting portion in an automobile engine part, but is not limited to this. As long as the second member is fastened to the first member made of the molded body via a metal fastening member integrated by insert molding, the present invention is equally applicable to this type of fastening portion in other industrial fields. can do. Moreover, the shape of the 1st member 1, the fastening member 2, the annular gasket 3, and the 2nd member 4 is not limited to the thing of an illustration.

It is a longitudinal cross-sectional view of the principal part which shows one Embodiment of the sealing structure of this invention. (A) (b) is a fragmentary sectional view which shows the point which insert-molds the 1st member and fastening member in the sealing structure by injection molding, (a) is the state before injecting a synthetic resin, ( b) shows the state of injection. (A) and (b) are the fragmentary sectional views which show the modification of the initial shape before shaping | molding of the annular gasket in the same sealing structure. It is sectional drawing of the principal part in the sealing structure of other embodiment. It is sectional drawing of the principal part in the sealing structure of other embodiment. It is a longitudinal cross-sectional view of the principal part which shows an example of the conventional sealing structure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st member 1a Part of synthetic resin 1b Part of synthetic resin 1c Part of synthetic resin 2 Fastening member 2b Concave part 2c Concave part 3 Annular gasket 3b Bead part 3c Part of elastic body 3d Part of sink 3g Part of elastic body 3h sink part 4 second member L fastening direction

Claims (5)

Fastening by a first member made of a synthetic resin molded body, a metal fastening member integrated with the first member by insert molding, and a second member fastened to the first member via the fastening member A sealing structure in the section,
Between the first member and the fastening member, an annular gasket made of an elastic body integrated with the insert molding in a state fitted to the outer peripheral portion of the fastening member is interposed,
A sealing structure in which the annular gasket is compressed in the fastening direction during the fastening, whereby the first member and the second member are sealed. The sealing structure according to claim 1,
A recess is formed at the outer peripheral portion of the fastening member and at the interface with the annular gasket, and a part of the elastic body constituting the annular gasket is elastically deformed in the recess by the molding pressure at the time of the insert molding. Sealing structure characterized by being in a state of entering. The sealing structure according to claim 2,
A sink part due to the elastic deformation is formed in an outer peripheral part corresponding to the concave part of the fastening member in the annular gasket, and a part of the synthetic resin constituting the first member enters the sink part and is integrated. The sealing structure characterized by having. The sealing structure according to any one of claims 1 to 3,
An annular chevron bead portion is formed so as to protrude from a portion of the annular gasket to which the fastening pressure is applied. The sealing structure according to any one of claims 1 to 4,
The first member and the fastening member are provided with an interface that directly merges, a recess is formed in the interface of the fastening member, and a part of the synthetic resin that constitutes the first member is engaged with the recess to be integrated Sealing structure characterized by being made.

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