JP5442591B2 - Manufacturing method of gasket - Google Patents

Description

  The present invention provides a resin container for interposing a gasket between two members so that both members are hermetically and watertightly sealed, in particular, between a bag body and a lid of an automobile battery case. The present invention relates to a method for manufacturing a gasket.

  In recent years, a mounting member such as a housing or a case on which a gasket is mounted has been made lighter by changing the material from metal to resin. Resin members have relatively large dimensional variations (for example, groove tolerance), surface waviness, or creep deformation compared to metal members. For this reason, low resilience is required for the gasket interposed between the resin bag main body and the lid of the battery case for automobiles, and may have a hollow cross-sectional shape.

  The gasket is formed by connecting both ends of the extruded product having a hollow cross section to form an annular shape. As a connection method for connecting an extruded product having a hollow cross section, a method using a metal core is known. In this method, an inner core is inserted into the hollow portion of an extrusion molded product, both ends are connected, and the both ends are connected by molding the connecting portion. It is a method of taking out. The cut portion may be used as it is, but depending on the application, it may be used after being sealed with an adhesive.

  Patent Document 1 proposes a method of manufacturing a weather strip 100 that includes a hollow seal portion 102 as shown in FIG. In this method, the holding member 110 is attached to the core 120, and the mold forming portion 104 is formed in this attached state, and then the core 120 is operated by operating the operating arm 122, so that the core is removed from the previously provided core punching hole 106. It is a method of extracting.

JP 10-309752 A

  However, it is clear that the sealing performance of the gasket having the cut portion in the vicinity of the mold forming portion is lowered. In addition, there is a possibility that a step is formed on the bonding surface even when the cut portion is sealed with an adhesive, or a hardness change due to the adhesive occurs. Furthermore, there is a problem in terms of reliability of adhesiveness over time.

  In the weather strip 100 disclosed in Patent Document 1, the core punching hole 106 after the core is taken out is left open or closed by moving the holding member 110. However, in this case as well, a decrease in sealing performance is inevitable as described above.

  The present invention has been made to solve the above problem, and when connecting both ends of the extruded portion to form an annular gasket, the reaction force of the molded portion after the connection is suppressed, and the entire circumference is reduced. It is an object of the present invention to provide a method for manufacturing a gasket having a stable sealing property.

  The manufacturing method of the gasket of the present invention includes an extrusion forming step of forming an extruded portion having a hollow seal portion by extrusion molding, a connecting step of connecting both end portions of the extruded portion to form a connecting portion, and a connecting portion with a predetermined portion. A mold forming step in which both ends are molded together with an unvulcanized material disposed between both ends in the mold, and the connecting portion is an end of a connecting piece made of a softer material than the extruded portion. The portions are respectively inserted into hollow seal portions at both end portions of the extrusion portion.

Here, it is desirable that the unvulcanized material is affixed to the end face on at least one side of the extruded portion before the connecting step. Or you may arrange | position so that the clearance gap provided between the both ends of the extrusion part may be filled with a string-form or plate-shaped unvulcanized material after a connection process.
Moreover, it is preferable that such a connection piece is a hollow body or solid body having a circular cross section.

  According to the gasket manufacturing method of the present invention, the connection is performed by inserting both ends of the connecting piece into the hollow portions at both ends of the extruded portion, respectively, and connecting them. This is realized by molding a vulcanized material. And it is not necessary to take out the connection piece arrange | positioned in the shaping | molding part. Therefore, there is no slit for taking out the core or an adhesive part bonded with the slit in the molded part of the gasket. Further, since the connecting piece is made of a softer material than the extruded portion, even if it remains in the molded portion as it is, the molded portion does not generate a significantly higher reaction force than the extruded portion. Therefore, even if the mold part in which the connecting piece is present is sandwiched between resin cases, the gasket can exhibit a stable low reaction force and good sealing performance over the entire circumference.

  Further, in the gasket manufacturing method of the present invention, the unvulcanized material to be the mold forming part is placed in the gap between the both end parts before or after the connecting step, and then the mold is formed. Therefore, since the high pressure as injecting by injection molding is not applied to the connecting piece, the hollow portion of the molded part is formed in a stable state. Therefore, the gasket according to the present invention can exhibit a more stable low reaction force and good sealing performance over the entire circumference.

  As described above, since the core is not used in the gasket manufacturing method of the present invention, it is not necessary to tear the hollow seal portion and take out the core, and the number of work steps can be reduced as compared with the conventional manufacturing method.

It is a top view which shows the outline | summary of the gasket which becomes this embodiment. It is sectional drawing which shows the extrusion part cross section of the gasket which becomes this embodiment. It is sectional drawing which shows the shaping | molding part cross section of the gasket which becomes this embodiment. It is explanatory drawing which shows the procedure which produces a connection part. It is a perspective view explaining a prior art.

  Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to FIGS.

  The gasket 1 according to the present embodiment is a gasket that is suitable for being attached to a resin battery case that houses a battery pack such as a hybrid vehicle or an electric vehicle and preventing moisture from entering the battery pack.

  FIG. 1 is a plan view showing the gasket 1. The gasket 1 is formed into an annular shape by connecting both end portions 10a and 10b of a single extruded portion 10 extruded and cut to a predetermined length by a molded portion 20 formed by molding.

  The AA cross section of the extrusion part 10 is shown in FIG. The extruded portion 10 is a rubber elastic body in which a solid seal portion 12 that is solid and a hollow seal portion 16 that has a hollow portion 18 that is continuous in the circumferential direction are integrally formed.

  As the rubber elastic body constituting the extrusion unit 10, an elastic material such as a thermoplastic elastomer, for example, ACM (acrylic rubber), NBR (nitrile rubber), EPDM (ethylene propylene rubber), FVMQ (fluorosilicon), or the like is preferably used. be able to. In the present embodiment in which the battery case is made of resin, EPDM is particularly preferable.

  The solid seal portion 12 of the extruded portion 10 has a substantially rectangular cross section, and a seal rib 17 is provided on the bottom portion so as to protrude more reliably.

  When the solid seal portion 12 is held in an attachment groove (not shown), the hollow seal portion 16 of the extrusion portion 10 is located outside the attachment groove. The hollow seal portion 16 has an arcuate side wall portion 19 extending in an arc shape with a substantially uniform thickness, and the arcuate side wall portion 19 defines the hollow portion 18. The arc-shaped side wall portion 19 is formed with a seal lip 14 that is inclined and extended so that the tip portion of the arcuate side wall portion is directed toward the upper outer peripheral side with the vicinity of the apex portion on the inner peripheral side as a base portion.

  FIG. 3 shows a BB cross section of the molded part 20. The mold forming part 20 is formed in substantially the same cross-sectional shape as the extrusion part 10. And in the hollow seal part 26 in the molding part 20, the connection piece 30 is arrange | positioned in order to hold | maintain the shape of the hollow seal part 26 while connecting the both ends 10a and 10b of the extrusion part 10. As shown in FIG. The connecting piece 30 is a tubular elastic member having a hollow portion 32 and a substantially circular cross section. The connecting piece 30 is disposed in the hollow seal portion 16 of the end portions 10a and 10b of the extruding portion 10 on both sides from the molding portion 20, and the hollow portion 32 communicates with the hollow portion 18 of the end portions 10a and 10b. doing.

  When manufacturing the gasket 1, first, in an extrusion molding process, an extruded body having a cross-sectional shape shown in FIG. 2 is formed, and the extruded body is cut into a predetermined length to form an extruded portion 10. Next, in the connecting step, the both end portions 10 a and 10 b of the extruding unit 10 are connected via the connecting piece 30 to form the connecting portion 40. In the mold forming step, the connecting portion 40 is disposed in a predetermined mold 50, and the both end portions 10a and 10b are molded together with the unvulcanized material disposed between the both end portions 10a and 10b.

  Here, an unvulcanized material having the same cross-sectional shape as the cross section of the extruded portion 10 may be attached to one end surface of the extruded portion 10 before the connecting step. Or after a connection process, you may make it fill with the string-form or plate-shaped unvulcanized material to the clearance gap between connection parts.

  Hereinafter, the connecting step and the mold forming step will be described in detail. FIG. 4 is an explanatory diagram for explaining each step (ad) in the connecting step.

  First, the connecting piece 30 is prepared. The hollow seal portion 26 in the mold forming portion 20 is formed thicker than the hollow seal portion 16 in the extrusion portion 10 by the wall thickness of the inherent connecting piece 30. Therefore, the material of the connecting piece 30 must be selected to be softer than the extruded portion 10 so that the reaction force of the mold forming portion 20 does not become significantly higher than the reactive force of the extruded portion 10. Therefore, it is desirable that the hardness of the connecting piece 30 is approximately 20 to 70% of the hardness of the extruded portion 10 in consideration of the increase in hardness after vulcanization. If it is less than 20%, it is too soft and the workability of the connecting operation of inserting the connecting piece 30 into the hollow part 18 of the extruding part 10 and connecting the both end parts 10a, 10b is lowered. On the other hand, if the hardness exceeds 70%, the reaction force of the molded part 20 may be significantly higher than the reaction force in the extrusion part 10. Further, it is desirable that the connecting piece 30 is vulcanized and bonded to the mold part material after molding, and therefore, it is desirable that the connection piece 30 is made of the same kind of material as the extruded part 10. From these viewpoints, for example, when the extrusion part 10 is EDPM having a hardness of 55 ° (Shore A), the connection piece 30 is suitably an EDPM sponge having a hardness of 40 ° to 60 ° (Shore E). It is.

  Moreover, in this embodiment, the connection piece 30 is a straight tube with a circular cross section having a cross-sectional shape different from the peripheral wall cross section of the hollow portion 18 in the hollow seal portion 16. Thus, when the cross-sectional shape of the hollow part 18 of the extrusion part 10 and the cross-sectional shape of the connection piece 30 differ, the edge part 10a, 10b of the extrusion part 10 and the edge part 30a, 30b of the connection piece 30 deform | transform, respectively. Therefore, the reaction force can be smoothly changed from the extruded portion 10 to the molded portion 20. The degree of change in the reaction force in the vicinity of the molded part 20 can be adjusted by appropriately selecting the wall thickness of the connecting piece 30, and the connecting piece 30 can be solid (cylindrical). .

  Further, in the present embodiment, the length L of the connecting piece 30 is not particularly limited, and the end portions 30a and 30b of the connecting piece 30 are easily detached from the hollow portion 18 in a connected state with the both end portions 10a and 10b. It is sufficient that the length is not so long. For example, the length L of the connection piece 30 may be 3 to 7 times the outer diameter d.

  After preparing the connection piece 30 as described above, in step (a), the both end portions 10a and 10b of the extrusion unit 10 are arranged facing each other at an appropriate interval, and in step (b), the connection piece 30 is arranged. The one end 30 a of 30 is inserted into the hollow portion 18 of the one end 10 a of the extruding part 10 up to about half (1/2 L) of the length L of the connection piece 30.

  Next, in step (c), the other end portion 30 b of the connecting piece 30 is inserted into the hollow portion 18 of the other end portion 10 b of the extruding portion 10 with the one end portion 10 a and the gap 42 therebetween. Here, the width w of the gap 42 is preferably 0.5 to 10 mm. When the width w is less than 0.5 mm, in the molding process, there may be a case where good vulcanization adhesion by the molding parts 20 of the extrusion part both ends 10a and 10b cannot be obtained. On the other hand, if the width w exceeds 10 mm, the connecting piece 30 may be deformed when the vulcanized material is disposed, and the surface of the mold part 20 may be deformed as the connecting piece 30 is deformed. So it is not appropriate.

  As described above, the connecting portion 40 in which the both end portions 10 a and 10 b of the extrusion portion 10 are connected via the connecting piece 30 can be formed. In step (d), the connecting portion 40 is placed in a predetermined mold 50. In addition, when a non-vulcanized material having the same cross-sectional shape as the cross section of the extruded portion 10 is pasted to one end surface of the extruded portion 10 before the connecting step, the length of the unvulcanized material to be pasted is determined in step (c). Similar to the width w of the gap 42, it may be 0.5 to 10 mm.

  Next, in the mold forming process, the unvulcanized material formed in a string shape or a plate shape is filled into the gap 42 of the connecting portion 40 to perform mold forming. That is, after the connecting portion 40 is arranged in the predetermined mold 50 in (d), the outer periphery of the connecting piece 30 in which the unvulcanized material formed in a string shape or a plate shape is exposed in the gap 42 In addition, the mold portion 20 is formed by filling the gap 42 along the outer peripheral shape of the end portions 10a and 10b and maintaining the temperature at a predetermined temperature. The vulcanization adhesion conditions (temperature, time) and the like of the molded part 20 may be performed in the same manner as in the conventional technique using a core. Then, after the vulcanization adhesion is completed, the molded part 20 is taken out from the mold 50.

  In this way, the connecting piece 30 is disposed in the hollow seal portion 26 while being held by the EDPM rubber that constitutes the mold forming portion 20.

  The method for manufacturing a gasket according to the present invention can be suitably used for manufacturing a gasket to be mounted on a resin battery case that houses a battery pack such as a hybrid vehicle or an electric vehicle.

1: Gasket 10: Extrusion part 10a, 10b: Extrusion part end part 12: Solid part 16: Hollow seal part 18: Hollow part 20: Molding part 26: Hollow seal part 30: Connection piece 32: Hollow part 30a, 30b : End part of connecting piece 40: Connecting part 42: Clearance 50: Mold 102 Hollow seal part 110: Holding member 120: Core

Claims (4)

An extrusion process for forming an extruded portion having a hollow seal portion by extrusion molding; and
A connecting step of connecting both ends of the extruded portion to form a connecting portion;
A mold forming step in which the connecting portion is disposed in a predetermined mold and the both end portions are molded together with an unvulcanized material disposed between the both end portions;
The manufacturing method of a gasket, wherein the connection portion is formed by inserting end portions of a connection piece made of a material softer than the extrusion portion into the hollow seal portions at both ends of the extrusion portion.   The method for manufacturing a gasket according to claim 1, wherein the unvulcanized material is affixed to an end face on at least one side of the extruded portion before the connecting step.   The said connection part has a clearance gap between the said both ends connected, The manufacturing of the gasket of Claim 1 by which the said unvulcanized material of a string form or plate shape is arrange | positioned in this clearance gap after the said connection process. Method.   The method for manufacturing a gasket according to claim 1, wherein the connecting piece is a hollow body or a solid body having a circular cross section.

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