JPH0721864A - Grommet - Google Patents

Abstract

PURPOSE:To prevent a waterproof filler to be filled in a grommet from being peeled from the grommet inner wall to cause water penetration. CONSTITUTION:In a grommet having a panel installing part 11 having a radially extended hole 12 and a wire insert part 13 having a radially contracted hole 14 continued to the center of the radially extended hole, which are formed by integrally molding rubber. a number of filler adhering ribs 15 protruding from the inner wall surface of the radially extended hole in parallel to the wire harness insert direction are integrally provided thereon, and a filler is adhered to the ribs, whereby the adhesive strength between the filler and the grommet is enhanced. The ribs 15 have the same form in the wire harness insert direction so that no undercut part is formed at molding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grommet mounted in a state in which a wire harness is inserted into a vehicle body panel hole or the like, and more particularly to a structure for improving the adhesiveness of a filling material filled in the wire harness insertion hole of the grommet to the grommet. In addition, the grommet having the above structure can be easily molded with a mold.

[0002]

2. Description of the Related Art In a wire harness for an automobile, when the wire harness is wired by penetrating a panel hole of a vehicle body or equipment, the wire harness is preliminarily penetrated through a wire harness insertion hole provided in a rubber grommet. The grommet is attached to the panel hole in this state to make it waterproof, dustproof and soundproof. However, even if the wire harness is inserted through the grommet, if a gap is created between the wire harness and the inner surface of the wire harness insertion hole of the grommet, water will be generated through the gap. Therefore, in the grommet which is attached to a location where water is likely to occur, a liquid curable filling material is filled between the inner surface of the wire harness insertion hole and the wire harness to improve the waterproof performance.

That is, as shown in FIG. 9, the grommet 1 has a shape in which a panel mounting portion 1a having a substantially large-diameter cylindrical portion and an electric wire insertion portion 1b having a small-diameter cylindrical portion are integrally formed with rubber by a mold. In addition, the expanded diameter hole 1c formed of the hollow portion of the panel mounting portion 1a and the reduced diameter hole 1d formed of the hollow portion of the wire insertion portion 1b.
Are connected to form a wire harness insertion hole, and a panel locking groove 1f is provided on the outer peripheral surface of the panel mounting portion 1a. A wire harness W, which is a bundle of a plurality of electric wires 2, is passed through the wire harness insertion hole 1e, and a filling material 3 is filled between the wire harness W and the expanded diameter hole 1c.

Urethane resin is mainly used as the above-mentioned filler 3, while EPDM is mainly used as a rubber material molded as a grommet. Filler 3 made of the above urethane resin and EPDM
The compatibility with the grommet 1 made of is poor in adhesiveness and easily peels off. Therefore, even if the expanded material 1c is filled with the filler 3,
When a force is applied to the wire harness and / or the grommet and the wire harness is pulled, the filler 3 is peeled from the grommet 1 and the electric wire 2, and there is a problem that a gap is likely to occur.

To solve the above problem, FIG. 10 (A)
As shown in (B), the inner peripheral wall of the panel mounting portion 1a, that is, the inner peripheral surface of the diameter-expanding hole is provided with a convex portion 1g protruding in the circumferential direction or a concave portion 1h recessed in the circumferential direction to separate the filler. A structure having a structure for preventing the above has been proposed. (Actual Kaihei 1-
(Japanese Patent No. 66713)

[0006]

[Problems to be Solved by the Invention] FIG. 10 (A) described above.
When the convex portion 1g or the concave portion 1h is provided in the circumferential direction shown in (B), when the grommet is molded with a mold, the molding mold 8
Is a mold 8a, 8b divided in the wire harness insertion direction
Since the undercut portion U is formed, the releasability from the mold becomes very poor, and cracks are likely to occur in the convex portion 1g or the concave portion 1h at the time of demolding. Further, when the wire group of the wire harness is inserted into the grommet and expanded by a grommet expander, a larger crack may spread from the crack to the entire grommet, and the grommet may become unusable.

Further, a convex portion 1g formed in the circumferential direction,
Since the recess 1h is a direction orthogonal to the insertion direction of the wire harness W (direction A in the drawing), when a force in the direction A is applied to the wire harness W, the protrusion 1g and the recess 1h serve as stoppers. Although the peeling of the filler 3 is suppressed, when a force in the B direction orthogonal to the A direction acts on the grommet 1, it does not help prevent the filler 3 from peeling. A force in the B direction on the grommet 1 may be generated at the time of assembling the wire harness, and when the grommet is attached to the vehicle, the grommet often interferes with other parts and is pulled in the B direction. . In this way, when the force in the B direction acts on the grommet 1 and the filler is once separated from the inner surface of the grommet, a gap is created and water is generated from the gap.

Furthermore, when the grommet is attached to a vehicle, it is very rare that the wire harness W is linearly wired in the A direction, and the wire harness W is bent in the D direction inside the panel P or outside the panel. It is often refracted in the E direction. When the wire harness W is thus refracted, for example, when it is refracted in the D direction, the grommet 1 is moved to the left side in the drawing, and naturally the filler 3 is also moved to the left side so that the right side of the filler 3 and the grommet. Gap S between the inner surface
(Shown by cross hatching in FIG. 10B) will occur. When the gap S is generated in this manner, water infiltration occurs through the gap as in the above.

The present invention has been made in view of the above-mentioned problems, and eliminates the occurrence of undercut during molding with a mold so that cracks do not occur at the time of demolding, and the wire harness and the grommet are used. The purpose is to prevent the filler from peeling off from the inner wall of the grommet even if a force is applied from the direction to pull it.

[0010]

In order to achieve the above object, the present invention provides a panel mounting portion having an enlarged diameter hole and an electric wire insertion portion having a reduced diameter hole continuous with the center of the enlarged diameter hole. In a grommet formed by integrally molding rubber with a mold, in parallel with the wire harness insertion direction that passes through the wire harness insertion hole consisting of the continuous expanded diameter hole and the reduced diameter hole, from the inner wall surface of the expanded diameter hole. It is intended to provide a grommet characterized in that a large number of ribs for adhering a filler are integrally projected.

The panel mounting portion having the expanded diameter hole has a shape in which a conical cylindrical portion is continuous from one end of a substantially cylindrical portion having a panel locking groove on the outer peripheral surface toward the wire insertion portion. It is preferable that a conical hole portion is provided on the side continuous with the diameter-reduced hole, and the rib is provided in the conical hole portion.

The ribs are formed so that the ribs protrude from the inner wall surface toward the center in the radial direction and are provided at regular intervals in the circumferential direction, and the outer peripheral surface of the wire harness through which the center of the diameter expanding hole is inserted and the diameter expanding hole. It is preferable to provide them so as to be radially arranged between the inner wall surface and the inner wall surface. At that time, for example, six or eight ribs are formed at intervals in the circumferential direction. Further, the ribs may be composed of ribs that are long in the radial direction and that are in contact with the outer peripheral surface of the wire harness, and ribs that are short in the radial direction and that are arranged in the middle of the long ribs, and the number of ribs may be increased. Further, each rib may be provided with a protrusion having the same shape in the wire harness insertion direction.

Alternatively, the ribs may be curved and projected from the inner wall surface of the diameter-expanding hole toward the center, or may be protruded in the shape of a round bar from the bottom wall of the diameter-expansion hole. That is, as described above, any shape may be used as long as it has the same shape in the wire harness insertion direction and does not cause an undercut portion during molding with a mold.

Further, a cylindrical inner cylinder may be provided so as to surround the large number of ribs so as to project from the inner wall inside the enlarged diameter hole, and the filling material may be filled inside the inner cylinder.

The rib is provided inside the diameter-expanding hole on the side of the diameter-reducing hole so that the rib does not project toward the opening side, and the diameter is expanded with the wire harness inserted through the diameter-expanding hole and the diameter-reducing hole. The hole is filled with the filling material, and the filling material is filled with the rib, the inner wall surface of the diameter-expanding hole and the outer peripheral surface of the wire harness, and also on the opening side of the diameter-expanding hole where the rib is not projected. The filling material is filled and the filling material filled between the ribs is integrally connected.

[0016]

[Operation] When the ribs are provided on the expanded portion of the grommet,
Since the ribs are formed so as to have the same shape in the wire harness insertion direction, an undercut portion does not occur at the time of molding with a mold, and a crack does not occur in the rib at the time of mold release, and the rib The crack does not spread to the entire grommet.

After the wire harness is passed through the wire harness insertion hole in which the diameter-expanded hole and the diameter-reduced hole are connected to the grommet, the diameter-expanded hole is filled with a liquid filler and solidified. Since the filler is bonded to a large number of ribs, the bonding area is greatly expanded, the adhesive strength between the filler and the grommet is enhanced, and the peeling of the filler and the grommet can be reliably prevented. Further, since the filler to be filled between the ribs is integrally connected by the filler to fill the portion where the rib is not provided, it is possible to prevent the displacement of the filler to be filled between the ribs. Even if an external force acts on the grommet and the wire harness that are adhesively held by the filler, the deformation can be suppressed.

[0018]

The present invention will be described in detail below with reference to the embodiments shown in the drawings. 1 to 3 show a first embodiment, and a grommet 10 of the first embodiment is shown in FIGS. 1 (A) (B) (C) (D).
It has the shape shown in. The grommet 10 has a shape in which a panel mounting portion 11 and a wire insertion portion 13 are continuously provided, and
As shown in FIG. 5, a molding die 16 composed of a pair of dies 16a and 16b is filled with molten rubber for integral molding.

The panel mounting portion 11 has a large-diameter cylindrical portion 11a on the open end side, a conical cylindrical portion 11b is provided continuously to the large-diameter cylindrical portion 11a, and a panel locking groove 11c is formed on the outer peripheral surface of the large-diameter cylindrical portion 11a. Is provided. The panel mounting part 1
The diameter-expanding hole 12 composed of one hollow portion is a conical cylindrical portion 11
The conical hole portion 12a is formed on the b side, and the conical hole portion 12a communicates with the reduced diameter hole 14 formed of the hollow portion of the wire insertion portion 13 to connect the reduced diameter hole 14 and the enlarged diameter hole 12 to each other. Thereby forming a wire harness insertion hole.

In the conical hole portion 12a of the expanded diameter hole 12,
Ribs 15 are formed by triangular flat plates that project from the inner wall surface toward the center at equal intervals in the circumferential direction. In this embodiment, eight ribs 15 are provided at intervals of 45 degrees, and the tips of these ribs 15 are arranged so as to be substantially in contact with the outer peripheral surface of the wire harness W to be inserted into the central portion of the expanded diameter hole 12. There is. Therefore, when the wire harness is inserted, it is positioned radially between the outer peripheral surface of the wire harness W and the inner wall surface of the enlarged diameter hole 12.

More specifically, each rib 15 is projected from the inner wall surface of the conical body in parallel to the wire harness insertion direction A, that is, in the vertical direction in the figure, and is in vertical contact with the outer peripheral surface of the wire harness W in the axial direction. Direction linear portion 15a and the linear portion 15a
It comprises an inclined portion 15b which is continuous from the lower apex along the inner wall surface of the diameter-expanding hole, and a lateral tip linear portion 15c which connects the inclined portion 15b and the upper end of the linear portion 15a. The lateral tip linear portion 15c does not protrude from the conical hole portion 12a of the diameter-expanding hole 12, and the rib 15 does not protrude from the opening side of the diameter-expanding hole 12.

The ribs 15 have a flat plate shape extending in the wire harness insertion direction and have the same shape in the wire harness insertion direction A. Therefore, as shown in FIG. 2, when forming the grommet 10 with the molds 16a and 16b, an undercut portion does not occur, and when the mold 16a forming the hollow part is released, the grommet including the rib 15 is formed. No cracks occur on any part of 10.

With respect to the grommet 10 having the above structure,
As shown in FIGS. 3A and 3B, the wire harness W is penetrated from the diameter-reduced hole 14 through the central portion of the diameter-expanded hole 12, and then the liquid filler 20 is injected into the diameter-expanded hole 12 and solidified. Let That is, the filler 20 is placed between the ribs 15 and the rib 1
It is made to flow from the upper end of 5 and is filled also in the upper part of the tip linear portion 15c. The filling material 20 thus filled has an inter-rib filling material 20a that solidifies in a horizontal trapezoidal shape between adjacent ribs 15, and a horizontal cross section in an annular shape on the upper side of the rib 15. It becomes the solidified filling material 20b,
The connecting filler 20b integrally connects all the inter-rib fillers 20a on the upper side.

The outer ribs of the inter-rib filling material 20a are bonded to the ribs 15 on both outer surfaces in the radial direction, the outer peripheral surfaces are bonded to the inner wall surface of the enlarged diameter hole 12, and the inner peripheral surface is the outer periphery of the wire harness W. It adheres to the surface. In this way, by increasing the adhesion area of the inter-rib filler 20a to the grommet 10, the adhesive strength is increased and the filler 20 is not easily separated from the grommet 10.

The connecting filler 20b is connected to the upper portions of all the rib filling members 20a, and the rib filling members 20a are connected to each other.
In other words, it functions as a lid, and the filling material between ribs 20
The position a is prevented from being displaced in the wire harness insertion direction A and the orthogonal B direction (radial direction).

After inserting the above wire harness W,
When the grommet 10 in which the expanded material 12 is filled with the filling material 20 is attached to the vehicle body panel hole, even if a tensile force is applied to the wire harness W and the grommet 10, the filling material 20
Wire harness W and grommet 10
Is held against the pulling force, and no gap is generated between it and the filling material 20.

For example, even if a pulling force in the direction A of the wire harness insertion direction acts on the wire harness W,
The inter-rib filling material 20a has a large adhesion area to the rib 15 and is strongly adhered to the grommet 10, and
Since they are integrally connected by the connecting filler 20b,
The filler 20 is not pulled away from the ribs 15 and the inner wall surfaces of the enlarged diameter holes 12 by being pulled together with the wire harness W.

When the grommet 10 is pulled in the B direction which is orthogonal to the A direction, the grommet 10 is pulled in FIG.
In (A), it tries to deform as shown by the alternate long and short dash line. However, since the inter-rib filling material 20a is connected by the connecting filling material 20b, the inter-rib filling material 20a is not displaced, and the inter-rib filling material 20a is not displaced. Since the rib 15 is adhered and held to the filler 20a in a large area, the grommet is prevented from being deformed, and thus the filler 20 and the inner wall surface of the grommet are prevented from being separated from each other.

Further, even when the wire harness W is bent in the D direction and the E direction, as described above, the positional displacement does not occur in the inter-rib filling material 20a and the positional displacement does not occur. Since the material 20 and the grommet 10 are bonded to each other in a large area via the ribs 15, deformation of the grommet is prevented, and as a result, peeling does not occur between the grommet 10 and the filler 20.

As described above, no matter which direction the force is applied to the wire harness W and the grommet 10, the inner wall surface of the grommet 10 and the filling material 20 are adhered and held so that no peeling occurs. There is no risk of water ingress from the gap, and the waterproof performance can be improved.

FIG. 4 shows a modification of the first embodiment, in which ribs 15h are provided on both side surfaces of the central portion of the rib 15 in the radial direction. The ridges 15h are continuously provided in the vertical direction, so that
The wire harness insertion direction A has the same shape. That is, by providing the protrusions 15h, an undercut portion is prevented from being generated at the time of molding the die.
Providing the ribs 15h on the ribs 15 can increase the adhesive area with the inter-rib filler 20a and increase the adhesive strength.

FIG. 5 shows a second embodiment, in which ribs 21 projecting from the inner wall surface of the diameter-expanding hole 12 in the radial direction are provided at the intermediate portions of the ribs 15 formed at intervals of 45 degrees. In addition, the tips 21a of these ribs 21 are enlarged in a spherical shape. The ribs 21 are also formed so as to have the same shape in the wire harness insertion direction A so that an undercut portion does not occur during molding of the mold. As described above, by providing the short rib 21 between the long ribs 15, the adhesive area between the filler 20 and the grommet is further increased, and the adhesive force is strengthened.

FIG. 6 shows a third embodiment in which ribs 22 projecting inward from the inner wall surface of the diameter-expanding hole 12 are curved. By thus bending, one rib 2
The area of No. 2 is increased to increase the adhesion area with the filler 20.

FIGS. 7A, 7B and 7C show a fourth embodiment. In each of the first to third embodiments, the inner wall surface of the enlarged diameter hole 12 is projected inward. Although a flat plate-shaped rib is provided, in the fourth embodiment, instead of the flat plate-shaped rib, the inner wall surface of the conical cylinder portion 11b on the diameter reducing side, that is, the diameter expanding hole 12 is formed.
In other words, a round bar-shaped rib 23 that protrudes in parallel with the wire harness insertion direction A is provided from the inner wall surface that is the bottom wall side.

The round bar-shaped ribs 23 are provided in large numbers at intervals in the radial direction and at intervals in the circumferential direction.
As a matter of course, the ribs 23 also have the same shape in the wire harness insertion direction so that an undercut portion does not occur at the time of molding the mold.

Even when the rod-shaped rib 23 is provided, the adhesive area between the filler 20 and the rib 23 can be increased and the adhesive strength between the filler 20 and the grommet 10 can be increased.

FIGS. 8A, 8B and 8C show a fifth embodiment in which the radially inner rib 15 is surrounded by the inner peripheral wall of the conical hole portion 12a of the diameter-expanded hole 12 so as to surround the radially outer rib 15. The tube 25 is provided so as to project in the wire harness insertion direction A. When the inner cylinder 25 is provided in this way and the filling material 20 is filled inside the inner cylinder 25, the filling material 20 is filled inside the inner cylinder 25 between the ribs 15 and above the ribs 15. Ribs 15,
It is bonded to the inner peripheral surface of the inner cylinder 25 and the outer peripheral surface of the wire harness.

When the inner cylinder 25 is provided, the grommet 1
When an external force is applied to the large-diameter cylindrical portion 11a of the panel mounting portion 11 of 0, the external force does not directly act on the filling material 20 due to the existence of the inner cylinder 25, and the filling material 20 and the inner cylinder 25 are separated from each other. Peeling can be prevented. Further, it is possible to reduce the cost by reducing the filling amount of the filling material 20.

[0039]

As is apparent from the above description, in the grommet according to the present invention, the ribs provided inside the diameter-expanded hole for increasing the adhesive strength with the filler for waterproofing and the like are provided in the wire harness insertion direction. Since they are projected in parallel and have the same shape in the wire harness insertion direction, it is possible to prevent an undercut portion from occurring by providing the rib when molding the grommet. Therefore, when releasing the molded grommet from the mold, the grommet can be molded easily and accurately without causing cracks in the grommet.

Further, since the ribs provided in the diameter-expanding hole are formed by a flat plate or the like radially arranged between the outer peripheral surface of the wire harness to be inserted and the inner peripheral surface of the diameter-expanding hole. It is possible to significantly increase the adhesive area between the filling material and the ribs to be filled in, and it is possible to dramatically improve the adhesive strength between the filling material and the grommet as compared with the conventional case. In addition, the filler to be filled between the ribs is connected to the filler to fill the enlarged diameter hole at a position beyond the rib so as to be integrated so as not to cause a positional deviation. Regardless of the external force applied to the grommet, the deformation of the wire harness and the grommet is suppressed by the adhesive force with the filler. In this way, while increasing the adhesive force between the filler and the grommet, and suppressing the deformation of the wire harness and the grommet, it is possible to reliably prevent the filler and the grommet from peeling off, thus,
It is possible to prevent the generation of water from the peeled portion.

[Brief description of drawings]

FIG. 1 shows a grommet according to a first embodiment of the present invention,
(A) is a perspective view, (B) is a plan view, (C) is C of (A).
-C line sectional drawing, (D) is the DD sectional view taken on the line of (A).

FIG. 2 is a schematic view showing a mold forming state of the grommet of the first embodiment.

3A and 3B show a state in which a wire harness is inserted into the grommet of the first embodiment and a filling material is filled therein. FIG. 3A is a horizontal sectional view and FIG. 3B is a vertical sectional view.

FIG. 4 is a schematic plan view of a grommet showing a modified example of the first embodiment.

FIG. 5 is a schematic plan view of a grommet according to a second embodiment.

FIG. 6 is a schematic plan view of a grommet according to a third embodiment.

FIG. 7 shows a grommet of a fourth embodiment, (A) is a perspective view, (B) is a schematic plan view, and (C) is a vertical sectional view.

FIG. 8 shows a grommet of a fifth embodiment, (A) is a plan view, (B) is a sectional view taken along line BB of (A), and (C) is a sectional view taken along line CC of (A). is there.

FIG. 9 is a cross-sectional view of a conventional grommet.

10A and 10B are cross-sectional views of a conventional grommet.

[Explanation of symbols]

 10 Grommet 11 Panel mounting part 12 Expanded hole 12a Conical hole part 13 Electric wire insertion part 14 Reduced diameter hole 15, 21, 22, 23 Rib 20 Filler 20a Rib filler 20b Connection filler W Wire harness

Claims (5)

[Claims] 1. A grommet in which a panel mounting portion having a diameter-expanding hole and an electric wire insertion portion having a diameter-reducing hole continuous with the center of the diameter-expanding hole are integrally formed of rubber by a mold to form a grommet. In parallel with the wire harness insertion direction which passes through the wire harness insertion hole consisting of the continuous expansion hole and the contraction hole, a number of ribs for adhering filler are integrally projected from the inner wall surface of the expansion hole. A grommet that is characterized by being. 2. The outer peripheral surface of the wire harness, wherein the ribs protrude radially from the inner wall surface of the diameter-expanding hole toward the center and are provided at regular intervals in the circumferential direction, and are inserted into the center of the diameter-expanding hole. The grommet according to claim 1, wherein the grommet is arranged radially between the inner wall surface of the expanded hole and the inner wall surface. 3. The grommet according to claim 1, wherein the rib is made to protrude in a rod shape from the inner wall surface on the bottom wall side of the enlarged diameter hole that is continuous with the reduced diameter hole. 4. The grommet according to claim 1, wherein the ribs have the same shape in the wire harness insertion direction and have a shape that does not cause an undercut portion during molding with a mold. 5. The rib is provided on the side of the reduced diameter hole inside the enlarged diameter hole so that the rib does not protrude toward the opening side,
The filler is filled in the diameter-expanded hole while the wire harness is inserted into the diameter-expanded hole and the diameter-reduced hole, and the filler is adhered to the ribs, the inner wall surface of the diameter-expanded hole, and the outer surface of the wire harness. In addition to filling, the filling material is also filled on the opening side of the expanded hole in which the rib is not projected, and the filling material filled between the ribs is integrally connected. The grommet according to any one of the preceding claims.