JPH11248044A - Hollow grommet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hollow grommet which does not require any separate member such as plug body, needs no plug fitting operation after molding, and provides good producibility of molding. SOLUTION: A hollow grommet 10B to be fitted in a linear body insertion through hole 20 formed in a plate member 12 holds a linear body 18 and seals the hole 20 approximately. The arrangement includes a mounting ring part 22 equipped with an outside shape capable of being attached to the hole 20, a holding cylinder part 24 to hold the inserted linear 18 in tight fit approximately, and a cover 26 to form a ring-shaped tight-closed space 28B in the area to the cylinder part 24. At least when the linear body is inserted, the forefront ring part 26b of the cover 26 is tightly contacted with the periphery of the cylinder part 24 so that the ring-shaped tight-closed space 28B is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hollow grommet made of a polymer elastic material which is attached to a linear body insertion hole formed in a plate-like member, holds the linear body, and substantially seals the insertion hole. About. In particular, when a wiring member (linear body) such as a wire harness is inserted from the inside of the vehicle body sheet metal to the outside of the vehicle, a wiring hole (for preventing noise or the like from entering the inside of the vehicle from the outside to the inside of the vehicle). The present invention relates to a hollow grommet suitable for use by being attached to a linear body insertion shaft).

[0002] In this specification, the terms "upper mold", "middle mold" and "lower mold", which indicate each part of a mold, are based on the case where the invention is applied to a vertical molding machine in injection molding or the like. However, when applied to a horizontal molding machine in injection molding, the names are different but the same. That is, usually, "upper type"
Becomes "fixed type" and "lower type" becomes "movable type".

[0003]

2. Description of the Related Art FIG. 1 shows an example of a use mode of a hollow grommet.

The hollow grommet 10 causes noise from the vehicle exterior 16 to the vehicle interior 14 when a wiring member (linear body) 18 such as a wire harness is inserted from the vehicle interior 14 to the vehicle exterior 16 of the metal sheet 12 of the vehicle. In order to prevent the intrusion of the wire, it is attached to the wiring hole (linear body insertion hole) 20 for use.

That is, the linear member 18 is mounted in a linear member insertion hole 20 formed in a plate member (vehicle metal plate) 12 to hold the linear member 18 and substantially seal the insertion hole 20.

The basic configuration of the hollow grommet 10 is that, in order to improve the noise intrusion prevention property, the mounting ring 22 having an outer peripheral shape that can be mounted in the linear body insertion hole 20 and the linear body 18 are substantially dense. It has a holding tube portion 24 that is inserted and held by fitting, and a cover portion 26 that forms an annular sealed space 28 with the holding tube portion 24.

[0007] The annular closed space 28 is for improving the noise intrusion prevention.

However, the annular closed space 28 cannot be formed at the time of forming the hollow grommet.

For this reason, conventionally, using a molding die 30 as shown in FIG.
After forming such that an annular gap 34 of at least 2 mm is formed between the annular gap 34 and the tip ring 32, the annular gap 34 is closed with a ring-shaped plug 36 such as cork as shown in FIG. Was. Here, the use of cork or the like as the plug 36 requires that the holding tubular portion 24 be tightly fitted to the linear body 18, and that the holding tubular portion 24 be tightly fitted to the tip ring portion 32 of the cover 26. That is because

As shown in FIG. 2, the molding die 30 is composed of an upper die 38, a middle die 40, a lower die 42, and a core 44, and the release is performed as follows.

As shown in FIG.
-The lower mold 42 is lowered and opened in a close contact state, and the core 44 is also lowered at the same time. By providing a space between the upper die 38 and the core 44, a molded product (hollow grommet) 1
This is for facilitating release from the core 44 of the cover 26, which is the outer peripheral portion of the cover 26.

The lowering of the core 44 is stopped at a constant stroke, and further, as the middle mold 40 and the lower mold 42 descend in close contact with each other, as shown in FIG.
The outer periphery is released from the core 44.

Thereafter, the lower mold 42 is opened with respect to the middle mold 40,
Assume the state shown in FIG. In this state, the molded article 1
Strip 0 by hand or machine.

[0014]

However, in the case of this method, it is necessary to prepare a separate member, and it takes time and effort to mount the plug after molding. Due to the above, there is a possibility that the airtightness may be deteriorated by moving to the inner annular airtight space side. For this reason, it is conceivable to use an adhesive or the like at the time of mounting the plug body, but it takes more time and is not desirable.

In order to solve the above-mentioned problems, a method for manufacturing a hollow grommet having the following structure is to provide a hollow grommet that does not require a separate member such as a plug and does not require a plug fitting operation after molding. Was developed (see Figs. 6 and 7).

First, a primary molded product 10A 'of a hollow grommet is preformed using a primary molding die 46 as shown in FIG. 6, and then a secondary molding die 50 as shown in FIG.
And vulcanization bonding (when the used material is rubber) or heat fusion (when the used material is a thermoplastic elastomer).

That is, the upper mold 52 and the first middle mold 5 shown in FIG.
4. Using a primary mold 46 consisting of a second middle mold 56 and a first lower mold 58, a hollow grommet annular closed space 28A
Is formed in a state in which the annular bottom wall 60 forming the above is separated from the bottom of the mounting ring portion 22A. This primary molding is
If a rubber material is used, the process ends in a semi-vulcanized state. When a thermoplastic elastomer material is used, it is in a solidified (cured) state.

Then, the lower mold 58 and the second middle mold 56 are lowered in this order and removed from the upper mold 52 / first middle mold 54 assembly.

Next, as shown in FIG. 7, the upper mold 52 and the first middle mold 54 are moved to a second shaping position, which is another position, and the second lower mold (bottom portion) for final shaping the annular bottom wall 60. The secondary molding is completed by vulcanization bonding (in the case of rubber) or heat fusion or vibration fusion (in the case of thermoplastic elastomer) by bonding the annular bottom wall 60 to the bottom surface of the mounting ring portion 22A with a mounting type 62. . In addition, the annular bottom wall 60 and the mounting ring portion 22A
Bonding may be performed using an adhesive.

Subsequently, as shown in FIG.
The molded product 1 is lowered by lowering the second lower mold 62 while keeping the second lower mold 62 in close contact therewith.
The upper outer peripheral portion of 0A is released from the upper mold 52.

Next, the second lower mold 62 is lowered and opened with respect to the first middle mold 54, and the state shown in FIG. 9 is obtained. In this state, the molded product 10A is peeled off from the first middle mold 54 by hand or machine.

However, in the case of this manufacturing method, primary molding,
Two molding steps of secondary molding were required, and two types of lower dies, the first and second lower dies, had to be prepared. In the case of a thermoplastic elastomer, a heater and a vibration welding machine are required.

In view of the above, the present invention provides a hollow grommet that does not require a separate member such as a plug, does not require a plug fitting operation after molding, and has good molding productivity. The purpose is to:

[0024]

The hollow grommet according to the present invention solves the above-mentioned problems by the following constitution.

A hollow grommet made of a polymer elastic body, which is attached to the linear body insertion hole formed in the plate-like member, holds the linear body, and substantially seals the insertion hole. An attachment ring portion having an attachable outer peripheral shape, a holding cylinder portion that inserts and holds the linear body in a substantially close fit, and a cover portion that forms an annular sealed space between the holding cylinder portion, The distal end ring portion of the cover portion is closely attached to the outer periphery of the holding cylinder portion at least when the linear body is inserted, thereby forming an annular sealed space.

The hollow grommet having the above structure is usually formed so that the holding cylinder and the cover protrude in opposite directions with respect to the mounting ring, and either the holding cylinder or the cover is inverted. The configuration is formed.

In this case, it is desirable that the holding cylinder portion is formed to be inverted because the holding cylinder portion can be easily inverted.

Further, the mounting ring portion usually has an engagement groove portion which can be engaged with the edge of the linear body insertion hole of the plate-like member.

In the manufacture of a hollow grommet in which the holding cylinder is inverted, the holding cylinder is inverted by using a core having an engaging portion that engages with the distal end of the holding cylinder. It is desirable to perform this at the same time as molding.

In the case of this manufacturing method, it is desirable that the engaging portion of the core be engaged with the reinforcing rib at the tip end of the holding tube portion.

[0031]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a preferred embodiment of the present invention will be described with reference to FIGS. The same portions as those in the above-described example are denoted by the same reference numerals, and all or part of the description thereof will be omitted.

(1) A hollow grommet 1 made of a polymer elastic material, which is mounted in a linear body insertion hole 20 formed in the plate member 12 and holds the linear body 18 and substantially seals the insertion hole 20.
0B is a high-level conceptual configuration.

Here, the polymer elastic body is a concept including rubber and thermoplastic elastomer. As the rubber material, when applied as an automobile part, EPDM, CR, etc., which are excellent in heat resistance and weather resistance, can be suitably used,
As the thermoplastic elastomer, olefins, styrenes and the like can be suitably used.

(2) Basically, an attachment ring portion 22 having an outer peripheral shape attachable to the linear object insertion hole 20 and the linear object 1
And a cover portion 2 that forms an annular closed space 28 between the holding tube portion 24 and the holding tube portion 24 so as to be inserted and held substantially tightly.
6 is provided.

Here, the outer peripheral shape that can be attached to the linear body insertion hole 20 of the attachment ring portion 22 is, in the illustrated example, the engaging groove portion 2.
3, a groove may be formed on the plate-like member 12 side to hold the outer periphery of the mounting ring portion 22. Further, the mounting ring portion 22 may be screwed with a mounting plate as a mounting flange portion using a patch plate or the like. It may be clamped or the like.

The inner diameter of the holding cylindrical portion 24 is usually
Can be closely fitted. Specifically, the mounting ring 2
It is formed from the inside of 2 through a tapered diameter portion 25.

The cover 26 is attached to the mounting ring 22.
Curved portion 26a that curves from the outside to the inside, and the holding cylinder portion 2
4 and a distal end ring portion 26b closely fitted to the distal end.

Here, the annular closed space 28B is provided with the cover 2 when the linear body 18 is not inserted into the holding cylinder 24.
The sixth end ring portion 26b does not necessarily have to be closely fitted. At least when the distal ring portion 26b is inserted at least when the linear body 18 is inserted, the annular closed space 28B may be formed so as to be in close contact with the holding tube portion 24. That is, the diameter of the holding cylinder portion 24 may be expanded by the insertion of the linear body 18, and the holding cylinder portion 24 may be closely fitted to the distal end ring portion 26 b of the cover portion 26.

(3) Next, a description will be given of a case where the hollow grommet 10B shown in FIG. 10 of the above embodiment is manufactured as an example (see FIGS. 11 to 13).

That is, the fixed plate 66 and the upper die 6 shown in FIG.
8, a molding die 77 including a middle die 70, a first lower die 72, a second lower die 74, and a core 76 is used. The upper mold 68, the middle mold 70, the first lower mold 72, and the second lower mold 74 are molded products 1 before inversion.
0B ', and the core 76 is a molded product 10 before inversion.
Shape the inner surface of B '. Note that a piston portion 78 is formed at the tip of the upwardly extending portion of the core 76, and the piston portion 7
Numeral 8 slides in the sliding space 80 and can move up and down for a predetermined span.

As in the prior art, a molding material is injected into the product cavity 82 of the molding die 77 by injection, transfer, or the like, and is cured.

At this time, the inner diameter d of the holding cylinder 24 before inversion is obtained.
_1, the relationship between the inner diameter d ₂ of the distal ring portion 26b of the cover portion 26 is usually _{2mm ≧ d 1 -d 2 ≧ 0mm} . When d ₁ is equal to or less than d _2, it is difficult to secure tight fit between the holding cylinder portion 24 and the distal end ring portion 26 b of the cover portion 26.
If d ₁ is too large than d _2, it is difficult to turn over the holding cylinder 24. Note that the thickness of the holding cylinder portion 24 and the distal end ring portion 26b of the cover portion 26 is set to 1 to 2 mmt.

After the elapse of a predetermined molding time (vulcanization time in the case of rubber), the molds are opened in the following order to release the mold.

First, the middle mold 70 and the first and second lower molds 72,
74 is lowered in an integrated state. Then, the outer periphery of the attachment ring portion 22 is held by the middle mold 70 so that the molded product 10B 'before reversing cannot be pulled out upward.

For this reason, as shown in FIG.
Is pulled down by the molded product 10B 'by the length of the distal ring portion 26b of the cover portion 26, that is, by the stroke of the piston 78, and the outer periphery of the distal ring portion 26b is released.

In this state, the middle mold 70 and the first and second lower molds 72 and 74 are further lowered in an integrated state. Then, the lower end engaging portion 76a of the core 76 is engaged with the tip reinforcing rib 24a of the holding tube portion 24, and the holding tube portion 24 is about to be pulled up. Then, as shown in FIG. 13, the holding cylinder 24 is fitted inside the cover 26 while being inverted.

When the release of the core 76 from the molded product (hollow grommet) 10B is completed, the first and second lower dies 72 and 74 are further lowered as shown by the two-dot chain line, and And the state shown in FIG. 13 is obtained. In this state, the molded product 10B is peeled off from the middle mold 70 by hand or machine.

In the present embodiment, the inversion operation of the holding cylinder 24 is performed by pulling up the lower end of the holding cylinder 24 by the lower end engaging portion 76a of the core 76, but after the mold release, It may be performed manually or using a jig.

Further, as shown in FIG. 14 (state 10C before inversion), the hollow grommet may be configured such that the inversion base portion 24a of the holding tube portion 24 is in a bellows shape (at least one step).
This is desirable because the reversibility of the holding tube portion 24 is good.

[0050]

According to the hollow grommet of the present invention, as described above, the distal end ring portion of the cover portion is in close contact with the outer periphery of the holding cylindrical portion at least when the linear body is inserted, thereby forming an annular closed space. With such a configuration, the following operation and effect can be obtained.

The annular closed space having the above structure is formed so that the holding cylinder and the cover protrude in opposite directions with the mounting ring interposed therebetween, and one of the holding cylinder and the cover is inverted. Can be formed.

Therefore, the hollow grommet according to the present invention does not require a separate member such as a plug, and does not require a fitting operation of the plug after molding, and also has good molding productivity.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a mounting mode in a conventional example of a hollow grommet.

FIG. 2 is a schematic sectional view of the mold for molding the hollow grommet shown in FIG. 1 when the mold is closed.

FIG. 3 is a schematic cross-sectional view of the mold at the initial stage of opening.

FIG. 4 is a schematic cross-sectional view when the mold is opened at the same time.

FIG. 5 is a schematic cross-sectional view when the mold opening is completed.

FIG. 6 is a schematic sectional view of a primary molding die used for molding a hollow grommet which can solve the problems of the conventional example to some extent.

FIG. 7 is a schematic sectional view of the secondary molding die when the die is closed.

FIG. 8 is a schematic cross-sectional view when the mold is opened halfway.

FIG. 9 is a schematic cross-sectional view when the mold opening is completed.

FIG. 10 is a sectional view of a hollow grommet according to an embodiment of the present invention.

11 is a schematic cross-sectional view of a molding die used for manufacturing the hollow grommet of FIG. 9 when the mold is closed.

FIG. 12 is a schematic cross-sectional view at the initial stage of the mold opening.

FIG. 13 is a schematic cross-sectional view when the hollow cylinder is simultaneously inverted during the mold opening.

FIG. 14 is a cross-sectional view of the hollow grommet before the inversion of the hollow grommet showing the improved form of FIG. 10;

DESCRIPTION OF SYMBOLS 10, 10B, 10C Hollow grommet 10B 'Molded product before reversing 12 Body metal plate (plate member) 18 Wiring member (linear member 20 Wiring hole (linear member insertion hole) 22 Mounting ring portion 23 Mating groove portion 24 Holding tube portion 24a Tip reinforcing rib portion of holding tube portion 26 Cover portion 26b Tip ring portion of cover portion 28, 28B Annular sealed space 66 Fixed plate 68 Upper die 70 Medium die 72 First lower die 74 Second lower die 76 Core 76a Core lower end engaging part 77 Molding mold

Claims (6)

[Claims] 1. A hollow grommet made of a polymer elastic material, which is attached to a linear body insertion hole formed in a plate-like member, holds the linear body, and substantially seals the insertion hole, A mounting ring portion having an outer peripheral shape attachable to the body insertion hole, a holding tube portion for inserting and holding the linear body in a substantially close fit, and a cover portion forming an annular closed space between the holding tube portion and the holding tube portion And a tip ring portion of the cover portion on the outer periphery of the holding cylinder portion,
A hollow grommet wherein at least when the linear body is inserted, the hollow grommet is formed so as to form the annular closed space. 2. A hollow grommet made of a polymer elastic body, which is attached to a linear body insertion hole formed in a plate-like member, holds the linear body, and substantially seals the insertion hole. A mounting ring portion having an outer peripheral shape attachable to the body insertion hole, a holding tube portion for inserting and holding the linear body in a substantially close fit, and a cover portion forming an annular closed space between the holding tube portion and the holding tube portion The holding cylinder portion and the cover portion are formed so as to protrude in opposite directions with the mounting ring portion interposed therebetween, and one of the holding cylinder portion and the cover portion is formed to be inverted. A hollow grommet, characterized in that: 3. A hollow grommet made of a polymer elastic material, which is attached to a linear body insertion hole formed in a plate-like member, holds the linear body, and substantially seals the insertion hole. A mounting ring portion having an outer peripheral shape attachable to the body insertion hole, a holding tube portion for inserting and holding the linear body in a substantially close fit, and a cover portion forming an annular closed space between the holding tube portion and the holding tube portion A hollow grommet, wherein the holding cylinder portion and the cover portion are formed so as to protrude in opposite directions with respect to the mounting ring portion, and the holding cylinder portion is formed to be inverted. . 4. The mounting ring portion according to claim 1, wherein said mounting ring portion includes an engagement groove portion which can be engaged with and attached to an edge of the linear body insertion hole of said plate-shaped member. Hollow grommet. 5. The method for manufacturing a hollow grommet according to claim 3, wherein the holding cylinder portion is formed by inverting the core having an engagement portion engaging with a tip end side of the holding cylinder portion. A method for manufacturing a core grommet, wherein the method is performed simultaneously when releasing a mold. 6. The method for manufacturing a core grommet according to claim 4, wherein said engaging portion of said core is engaged with a reinforcing rib at the tip of said holding tube portion. .