JP2003324825A - Grommet and method of manufacture therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a grommet which allows component commonalization for each part, which has a good external appearance, and which has in addition a good water blocking property, and to provide a method of manufacture therefor. <P>SOLUTION: The grommet 10 comprises a thermoplastic elastomer tubular body, into which a wiring cable is inserted and is provided with a corrugated body section 31a, and attachment sections 11a, 21a on the two ends of the body section. The grommet 10 is made up of three components: two separate attachment components 11, 21, with the ends of the two attachment sections serving as bonding parts 13, 23 for bonding to the body section; and one body component 31 that is a separate component from the two attachment sections, with the two ends of the body section 31a serving as the bonding parts 32, 33 to the two attachment sections. The three components are respectively integrally bonded through welding. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grommet having a tubular body having a bellows-shaped main body and mounting portions at both ends of the main body, and a method for manufacturing the grommet.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 6, a grommet 60 made of a rubber tubular body in which a bellows-shaped main body 61 and mounting portions 62, 63 at both ends of the main body 61 are integrally molded.
Is used to protect electrical wiring cables that connect the doors and bodies of automobiles. Reference numeral 64 is an engaging groove for a mounting hole or the like formed in a steel plate on the body side of an automobile, and 65 is an engaging groove for a mounting hole formed in a steel plate on the door side of an automobile. Further, the grommet is usually different in size, shape and the like depending on the type of automobile.

[0003]

However, in the conventional grommet, both the mounting portions 62 and 63 and the main body portion 6 are provided.
Since 1 is integrally molded, it is necessary to create a mold for each product shape, even if only the mounting portions 62, 63 or the main body portion 61 have different sizes and shapes. However, the mold for the entire product has to be recreated, which causes a problem that the cost for creating the mold is high and it takes time. Further, since a complicated shape in which the bellows-shaped main body portion 61 and the mounting portions 62 and 63 are integrated is molded in the mold, it is difficult to remove the product from the mold, resulting in poor molding workability. is there. Furthermore, in inventory management of products, it is necessary to manage a large number of types of grommets according to the required size and the like, which is complicated.

[0004] There is also one in which the main body portion is eliminated and the both mounting portions are spirally wound with a resin tape, but in that case, not only does the appearance look bad, but also the waterproof performance is significantly deteriorated. There is a problem that rainwater and the like easily enter the body of the vehicle through the cable.

The present invention has been made in view of the above points, and provides a grommet and a manufacturing method thereof, in which parts can be made common to each part, the appearance is good, and water stopping property is good. To do.

[0006]

According to a first aspect of the present invention, there is provided a grommet having a tubular body having a bellows-shaped main body portion and mounting portions at both ends of the main body portion. Composed of separate parts made of plastic elastomer,
3 of two mounting parts in which ends of the both mounting parts on the main body part side are joint parts to the main body part, and one main body part in which both ends of the main body part are joint parts to the mounting part 3
It is characterized in that the components are welded and integrated at each of the joining portions.

According to a second aspect of the present invention, there is provided a grommet including a tubular body having a bellows-shaped main body and mounting portions at both ends of the main body. The grommet includes one mounting portion of the two mounting portions and the main body portion. A part up to the other mounting part is composed of separate parts made of thermoplastic elastomer, and one end part of the one mounting part on the main body part side is a joining part to the main body part; It is characterized in that two parts of a main body part and one mounting part integrated main body part whose end part on the side of the mounting part is a joining part for the mounting part are welded and integrated at each of the joining parts. .

According to a third aspect of the present invention, in the first or second aspect, the inner diameter of the main body component or the attachment portion-integrated main body component before joining is smaller than the outer diameter of the attachment component before joining. And the rigidity of the joint part of the main body part or the mounting part integrated main body part is lower than the rigidity of the joint part of the mounting part, and the joint part of the main body part or the mounting part integrated main body part is joined by elastic deformation. It is characterized in that it is covered on the outer surface of the portion and adheres to the outer surface of the joint portion of the mounting component, and the joint portion that adheres is welded.

According to a fourth aspect of the present invention, in the third aspect, the joint portion of the main body component or the attachment portion-integrated main body component and the joint portion of the attachment component are in close contact with each other via an elastomer containing a substance that generates heat by microwaves. It is characterized in that the intimately joined portion is heated and welded by a microwave.

According to a fifth aspect of the present invention, in manufacturing a grommet having a tubular body having a bellows-shaped main body and mounting portions at both ends of the main body, the both mounting portions and the main body are made of a thermoplastic elastomer. Two mounting parts, which are composed of separate parts, and whose main body side end parts of both mounting parts are joint parts to the main body part, and both ends of the main body part are joint parts to the mounting part, and the main body In the joint portion of the part, the rigidity is made lower than that of the joint portion of the mounting part, and the inner diameter of the joint portion of the main body part is smaller than the outer diameter of the joint portion of the mounting part. Using parts, the joint parts at both ends of the main body part are elastically deformed and closely adhered to the outer surfaces of the joint parts of the both mounting parts through an elastomer containing a substance that generates heat by microwaves. Wherein the fusing is heated using microwave radiation in junction that.

According to a sixth aspect of the present invention, in manufacturing a grommet having a tubular body having a bellows-shaped main body and mounting portions at both ends of the main body, one of the mounting portions and the main body portion are separated from each other. A portion up to the other mounting portion is made of a separate component made of a thermoplastic elastomer, and an end portion on the main body portion side of the one mounting portion serves as a joining portion to the main body portion.
And one attachment part, and the end part on the attachment part side of the main body part is a joint part for the attachment part, and the rigidity of the joint part of the main body part is lower than the joint part of the attachment part, and the main body The inner diameter of the joint portion of the portion is made smaller than the outer diameter of the joint portion of the mounting part 1
Two parts consisting of one mounting part integrated body part are used, and the joint part of the mounting part one body part is elastically deformed through an elastomer containing a substance that generates heat by microwaves on the outer surface of the joint part of the mounting part. It is characterized in that it is covered and adhered by the above, and the above-mentioned adhered joint portion is irradiated with microwaves to be heated and welded.

[0012]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in detail below with reference to the accompanying drawings. 1 is a sectional view of a grommet according to a first embodiment of the present invention, FIG. 2 is a sectional view showing components of the grommet according to the first embodiment, FIG. 3 is a sectional view of a grommet according to the second embodiment, and FIG. Sectional drawing which shows the component of the grommet of 2nd Example, FIG. 5: is sectional drawing of the grommet of 3rd Example.

A first embodiment of the grommet 10 shown in FIG.
Is used to protect the electric wiring cable that connects the vehicle door and the body, and is a bellows-shaped main body 31a.
And the attachment portions 11a and 21a at both ends of the main body portion 31, and are made of olefin (TPO) or styrene (TP).
It consists of a tubular body made of a thermoplastic elastomer (TPE) such as S). Further, as shown in FIG. 2, the grommet 10 of this embodiment has two mounting parts 11 and 21 constituting the mounting parts 11a and 21a at the both ends and a bellows-shaped main body part 3 at the center.
It is composed of three parts, one main body part 31 constituting 1a, and each is molded by injection molding or the like using a mold.

Of the two mounting parts 11 and 21, one is a mounting part 11 to the body and the other is a mounting part 21 to the door. The attachment part 11 to the body is formed in a substantially cylindrical shape, and has a groove 12 formed on the outer peripheral surface of the middle portion in the length direction,
The inner peripheral edge of the mounting hole formed in the steel plate of the body is the groove 1
It fits in 2. Further, an end portion of the attachment component 11 to the body on the main body component side is a joining portion 13 to the main body portion 31a.

The joint portion 13 of the attachment part 11 to the body is formed in a thick ring shape to enhance rigidity. In addition, in the joint portion 13 of this example, the fitting portion 14 is formed in the shape of a groove on the outer periphery, and the fitting portion 14 is provided with an elastomer E containing a heat generating substance that generates heat by microwaves, such as carbon black. ing. As the elastomer containing the exothermic substance, a thermoplastic elastomer (TPE) is suitable, and particularly, a mounting part 11 to the body.
Also, the same elastomer as the main body part 31 is preferable because it has excellent weldability. Further, the elastomer E containing the heat-generating substance is formed into a string shape or a tape shape so that the bonding portion 1
It may be wound around the outer peripheral surface of the wire 3.

The attachment part 21 to the door has a substantially cylindrical shape, and a groove 22 is formed on the outer peripheral surface of the middle portion in the longitudinal direction.
The inner peripheral edge of the mounting hole formed in the steel plate of the door is the groove 22.
It fits in. Further, the end portion on the main body portion side of the attachment part 21 to the door is a joint portion 23 to the main body portion 31a.

The joint portion 23 of the attachment part 21 to the door has a thick ring shape to enhance rigidity. Further, in the joining portion 23 of the attachment part 21 to the door in this example, a fitting portion 24 is formed in a concave groove shape on the outer peripheral surface of the joining portion 23, similarly to the attachment part 11 to the body, and An elastomer E containing a heat generating substance that generates heat by microwaves is arranged in the joint portion 24. As the elastomer containing the heat generating substance, a thermoplastic elastomer (TPE) is suitable, and in particular, the same elastomer as that of the attachment part 21 to the door and the main body part 31 is preferable because of excellent weldability. Further, the elastomer E containing the heat generating substance may be formed into a string shape or a tape shape and wound around the outer peripheral surface of the joint portion 23.

Both ends of the body part 31 are joint portions 32 and 33. The joint portion 32 at one end is for the joint portion 13 of the attachment part 11 to the body, and the joint portion 33 at the other end is for the joint portion 23 of the attachment part 21 to the door. Body part 3 of this example
1 is a bead-shaped annular protrusion 3 for both the joint portions 32, 33.
4, 35 are formed on the inner peripheral surface. The bead-shaped annular protrusions 34 and 35 are fitted portions 14 and 2 formed at the joint portions 13 and 23 of the both mounting parts 11 and 21, respectively.
4 is fitted through the heat generating substance-containing elastomer E.

Further, in the body part 31 of this embodiment, the inner diameter d31 before joining at the joining portion 32 at one end of the body portion 31a is the outer diameter d1 before joining at the joining portion 13 of the attachment part 11 to the body. The inner diameter d32 before joining at the joining portion 33 at the other end of the main body component 31 is smaller than that at the joining portion 2 of the attachment component 21 to the door.
It is smaller than the outer diameter d2 before joining in No. 3. Further, the joint portion 32 at one end of the main body portion 31a of the main body component 31 has a rigidity lower than that of the joint portion 13 of the attachment component 11 to the body, and the other end of the main body portion 31a of the main body component 31. Joining part 33 of
Has a lower rigidity than the rigidity of the joint portion 23 of the attachment part 21 to the door. In addition, gripping fins 36 and 37 are formed on the outer circumferences of the joint portions 32 and 33 at both ends of the main body 31a of the main body component 31, respectively.

The grommet 10 of the first embodiment has the above-mentioned 3
It is manufactured as follows using the parts. First, in the body part 31, the gripping fins 36, 37 on the outer periphery of the joint portions 32, 33 are pulled outward by a grommet manufacturing operator or the like, and the diameters of the joint portions 32, 33 are expanded. And the joint portions 32, 33 in the expanded state
Are covered on the outer peripheries of the corresponding joint parts 13 and 23 of the attachment parts 11 and 21, respectively.
The bead-shaped annular protrusions 34 and 35 are fitted in. As a result, the joint portions 32 and 33 of the main body component 31 are positioned in close contact with the outer peripheral surfaces of the joint portions 13 and 24 of the attachment components 11 and 21 via the heat generating substance-containing elastomer E. In addition, the joint portion 3 of the main body part 31
2 and 33 are joint portions 13 of the attachment parts 11 and 21,
The rigidity is lower than 23. Therefore, the joint portions 13 and 23 of the attachment parts 11 and 21 have little or no deformation, and the joint portions 32 and 23 of the body part 31 do not deform.
33 is closely fitted to the joint part 32 of the main body part 31,
33 is supported from the inside. It should be noted that the joint parts 32 and 33 of the main body part 31 and the joint part 1 of the attachment parts 11 and 21
Due to the elastic deformation, the joint portions 32 and 33 of the main body component 31 and the joint portions 13 and 23 of the mounting components 11 and 23 are different from each other in the rigidity difference and the difference between the inner diameter and the outer diameter.
The outer peripheral surface of the is covered by the range.

The joint portion 13 of the mounting parts 11 and 21,
In a state in which the joint portions 32, 33 of the main body component 31 and 23 are in close contact with each other, the joint portions 13, 23, 32, 33 are irradiated with microwaves by a known microwave heating device. As a result, the heat-generating substance-containing elastomer E between the joint portions 32 and 33 of the main body part 31 and the joint portions 13 and 23 of the attachment parts 11 and 21 is heated to generate heat, and the joint portion 32 between the elastomer E and the main body component 31. , 33 and the joint portions 13, 23 of the attachment parts 11, 21 are efficiently melted by heating and welded to each other to be joined and integrated to obtain the grommet 10 of FIG. 1. The microwave heating uses a higher frequency than the high frequency heating, and can safely heat a resin having a relatively small dielectric loss without causing discharge.

Grommet 4 according to the second embodiment shown in FIG.
0 is composed of two parts molded by injection molding or the like instead of the three parts of the first embodiment, and the two parts are joined and integrated by welding by microwave heating. In addition, this second
In the following embodiments, the same components as those in the first embodiment will be designated by the same reference numerals and detailed description thereof will be omitted.

As shown in FIG. 4, the two parts are one mounting part (mounting part to body) 11 which constitutes one of the mounting parts 11a and 21a (mounting part to body) 11a. And one mounting portion integrated main body part 41 integrally formed from the main body portion 31a to the other mounting portion (door mounting portion) 21a.

In the body mounting part 11 of the second embodiment, the end portion on the side of the main body portion 31a is a joint portion 13 to the main body portion 31a, and the joint portion 13 is the same as in the first embodiment. It is thick and has high rigidity. Also,
In the mounting portion integrated body component 41 in the second embodiment, the end portion of the body portion 31a on the side of the mounting portion 11a to the body is joined to the body mounting portion 11 by the joining portion 3
It is supposed to be 2. Further, the joint part 32 of the main body part 31 and the attachment part 1 to the body in the second embodiment.
The rigidity and the diameter are different from those of the joint portion 13 in No. 1 as in the first embodiment.

The grommet 40 of the second embodiment is manufactured as follows using the above-mentioned two parts. First, the gripping fin 36 on the outer periphery of the joint portion 32 in the mounting portion integrated main body component 41 is pulled outward by the manufacturing worker or the like to expand the joint portion 32, and the diameter of the joint portion 32 is expanded. The joint portion 32 is covered on the outer periphery of the joint portion 13 of the attachment part 11 to the body, and the fitting portion 14 of the joint portion 13 is fitted with the bead-shaped annular protrusion 34. As a result, the joint portion 32 of the mounting portion-integrated main body component 41 is positioned in close contact with the outer peripheral surface of the joint portion 13 of the mounting component 11 to the body via the heat generating substance-containing elastomer E. In addition, the joint portion 3 of the mounting portion integrated body part 41
No. 2 has a rigidity lower than that of the joint portion 13 of the mounting component 11 to the body, so that the joint portion 13 of the mounting component 11 to the body has little or no deformation, and the mounting portion integrated main body component 41. The fitting portion 32 is closely fitted to support the joining portion 32 of the mounting portion integrated main body part 41 from the inside. Then, the closely-bonded joint portion 1
By irradiating microwaves 3 and 32 with a microwave heating device, the exothermic substance-containing elastomer E is heated to efficiently weld and join the joining portions 13 and 32. As a result, the grommet 40 of the second embodiment shown in FIG. 3 is obtained.

In the first and second embodiments, a recessed groove is formed as the fitting portion 14 at the joint portion of the mounting component, and the main body component and the mounting component-integrated main body component are bead-shaped annular protrusions. Although the portions 34 and 35 are formed, the mounting portions 52, 54, 56 and 57 without the concave groove and the bead-shaped annular protrusion are attached as in the grommet 50 of the third embodiment shown in FIG. The joint parts 52, 54 of the parts 51, 53 and the joint parts 56, 57 of the main body part 55 are the above-mentioned elastomer E containing heat generating substance.
It is also possible that they are in close contact with each other and welded by a microwave. The grommet 50 of the third embodiment is composed of three parts, a body mounting part 51, a door mounting part 53, and a main body part 55.

In each of the above-described embodiments, the rigidity of the joint between the parts is made different by the difference in the thickness of the joint, but the rigidity may be made different by using materials having different hardness.

[0028]

As shown and described above, according to the present invention, the two mounting portions and the main body portion are three separate components, or one mounting portion from the main body portion to the other mounting portion. Since two parts are welded separately, the parts can be shared, and the number of parts can be reduced when inventory management of multiple grommets with different sizes and shapes for each part is performed. You can In addition, if you need a grommet with a different size or shape of the mounting part or body part due to changes in the usage target of the grommet, etc., it is only necessary to remake the mold for the parts that need to be changed, and therefore the grommet. Becomes cheaper, and the grommet manufacturing work becomes easier.

Further, according to the present invention, the rigidity of the joint part of the main body part or the mounting part integrated main body part is made lower than the rigidity of the joint part of the mounting part, and before the main body part or the mounting part integrated main body part is joined. By making the inner diameter of the joint part smaller than the outer diameter of the joint part before joining the mounting parts, deformation at the joint part can be suppressed and the joint part can be brought into close contact, and a jig that holds the joint part during welding Can be simplified or omitted, so that the manufacturing work can be simplified and the grommet can be inexpensive. Moreover, the joint between the mounting portion of the grommet and the main body portion is surely strengthened, and the waterproofness is increased.

Further, according to the present invention, an elastomer containing a substance that generates heat by microwaves is arranged between the joint portion of the main body component or the attachment portion-integrated main body component and the joint portion of the attachment component so that the microwave irradiation can be performed. Since the joint portion is welded by heating from the inside, the manufacturing work is simple, the excess portion is not heated, and the grommet in which the joint portion is welded and joined efficiently can be obtained. If a heating plate is used instead of heating by microwaves, it is easy to shift when melting, and if ultrasonic waves are used, fusion marks are likely to appear on the surface and the appearance is easily damaged. Since a transmission type material and a light absorption type material have to be selected, there are many restrictions, and in the case of an adhesive, sufficient adhesive strength cannot be obtained for an olefin-based elastomer.

[Brief description of drawings]

FIG. 1 is a sectional view of a grommet according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing components of the grommet of the first embodiment.

FIG. 3 is a sectional view of a grommet according to a second embodiment.

FIG. 4 is a sectional view showing components of the grommet of the second embodiment.

FIG. 5 is a sectional view of a grommet according to a third embodiment.

FIG. 6 is a sectional view of a conventional grommet.

[Explanation of symbols]

10, 40, 50 Grommet 11a, 21a Mounting part 11, 21, 51, 53 Mounting part 13, 23, 32, 33, 52, 54, 56, 57 Joining part 31a Main part 31, 55 Main part 41 Mounting part integrated main body Part E Elastomer-containing elastomer

Claims (6)

[Claims] 1. A grommet comprising a tubular body having a bellows-shaped main body portion and mounting portions at both ends of the main body portion, wherein the both mounting portions and the main body portion are formed of separate thermoplastic elastomer parts, 3 attachment parts in which end portions of both attachment parts on the main body side are joint parts to the main body part, and one main body part in which both ends of the main body part are joint parts to the attachment part 3
A grommet in which parts are welded and integrally bonded at each of the above-mentioned joining portions. 2. A grommet comprising a tubular body having a bellows-shaped main body portion and mounting portions at both ends of the main body portion, wherein one of the mounting portions and the main body portion to the other mounting portion. Part is made of separate parts made of thermoplastic elastomer, and one end part of the one mounting part is a joint part to the main part, and the mounting part in the main part. A grommet characterized in that two parts, one mounting part integrated main body part having a part side end part as a joining part for the mounting part, are welded and joined together at each of the joining parts. 3. An inner diameter of a main body part or a main body part integrated with a mounting part before joining at a joint part is smaller than an outer diameter of the main part part before joining at a joint part of the mounting part, The rigidity of the joint part is made lower than the rigidity of the joint part of the mounting part, and the joint part of the main body part or the mounting part integrated main body part is elastically deformed to cover the outer surface of the joint part of the mounting part and the outer surface of the joint part of the mounting part. The grommet according to claim 1 or 2, wherein the grommet is closely adhered to, and the closely joined portion is welded. 4. The main body part or the joint part of the main body part with the mounting part and the joint part of the mounting part are adhered to each other via an elastomer containing a substance that generates heat by microwaves, and the adhered joint part is formed by microwaves. The grommet according to claim 3, which is heated and welded. 5. When manufacturing a grommet comprising a tubular body having a bellows-shaped main body portion and mounting portions at both ends of the main body portion, the both mounting portions and the main body portion are made of separate parts made of a thermoplastic elastomer. , Two mounting parts whose end portions on the main body part side of the mounting parts are joint parts to the main body part, and both ends of the main body part are joint parts to the mounting parts, and at the joint parts of the main body part, Using three parts, one main body part whose rigidity is lower than that of the joining part of the attachment part, and the inside diameter of the joining part of the body part is smaller than the outside diameter of the joining part of the attachment part, The joint parts at both ends of the main body part are elastically deformed and closely adhered to the outer surfaces of the joint parts of the both attachment parts through an elastomer containing a substance that generates heat by microwaves, respectively, Manufacturing process of the grommet, characterized in that fusing and heated by irradiating a microwave. 6. When manufacturing a grommet formed of a tubular body having a bellows-shaped main body portion and mounting portions at both ends of the main body portion, one mounting portion of the both mounting portions and the main body portion to the other mounting portion. And a mounting part in which the end part on the main body part side of the one mounting part is a joint part to the main body part,
The mounting component side end portion of the main body portion is a joint portion for the mounting component, and the joint portion of the main body portion has rigidity lower than the joint portion of the mounting component,
In addition, two parts including one mounting part integrated main body part in which the inner diameter of the bonding part of the main body part is smaller than the outer diameter of the mounting part of the mounting part are used. The outer surface of the joining portion of the mounting part is covered by elastic deformation through an elastomer containing a substance that generates heat by microwaves to be adhered, and the adhered joining portion is irradiated with microwaves to be heated and welded. Characteristic grommet manufacturing method.