JP2005348488A - Grommet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a grommet that can constantly secure water cut-off performance. <P>SOLUTION: The grommet 10 is constituted such that: a diameter-expanded cylinder 12 is continuous to a small-diameter cylinder 11; a vehicle body engaging groove 13 is annularly formed at the external periphery of the diameter-expanded cylinder 12; the inside diameter of the diameter-expanded cylinder 12 is almost the same with that of the small-diameter cylinder 11; a wiring harness is penetrated through the opening end 20 of the diameter-expanded cylinder 12 from the small-diameter cylinder 11; and the rim of a penetration hole H of a vehicle body panel P is engaged with the vehicle engaging groove 13 and installed to the vehicle body panel P. The vehicle body engaging groove 13 is composed of a bottom wall 14 from which a main seal rib 14a is protruded, a large-diameter side wall 16 from which a sub-seal rib 16a is protruded, and a small-diameter side wall 15 that faces the large-diameter side wall 16. A stress absorbing groove 17 is protrusively formed on the bottom wall 14 from a corner that contacts with the large-diameter side wall 16, and a reinforcing rib 19 that suppresses the stress deformation of the large-diameter side wall 16 is arranged at a tip face 18 that surrounds the opening end 20 of the diameter-expanded cylinder 12. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a grommet, and more particularly, to a grommet that is externally mounted on a group of wires of a wire harness that is routed in an automobile and is attached to a through hole of a vehicle body panel to stop water.

  Conventionally, a grommet is attached to a wire harness routed from an automobile engine room to a vehicle interior, and the grommet is attached to a through hole of a vehicle body panel that separates the engine room from the vehicle interior. It is designed to protect and waterproof, dustproof, and soundproof from the engine room side to the passenger compartment. As this type of grommet, a so-called one-motion grommet is provided in which a vehicle body locking groove provided on the outer periphery of the grommet is locked to the periphery of the through hole simply by pushing the grommet into the through hole of the vehicle body panel from one direction.

  Specifically, as shown in FIG. 4, the grommet 1 includes a small-diameter cylindrical portion 2 and a large-diameter cylindrical portion 3 continuous to the small-diameter cylindrical portion 2. The vehicle body locking groove 4 is annularly recessed. As shown in FIG. 5, the vehicle body locking groove 4 includes a bottom wall 5 from which a main seal rib 5 a is projected, a large-diameter side wall 6 from which a sub-seal rib 6 a is projected, and a small-diameter side wall that faces the large-diameter side wall 6. 7.

  The grommet 1 is configured such that the wire harness W / H is passed from the small-diameter cylindrical portion 2 to the hollow portion of the enlarged-diameter cylindrical portion 3 and is fixed to the body panel from the small-diameter cylindrical portion 2 side with the tape T fixed to the distal end side of the small-diameter cylindrical portion 2. It is inserted into the through hole H of P, deformed so as to crush the small-diameter side wall 7 and passed through the through hole H, and the burring Pa on the periphery of the through hole H is dropped into the vehicle body locking groove 4 and locked. Yes. At this time, the main seal rib 5a and the sub seal rib 6a are crushed by the vehicle body panel P to ensure surface pressure, that is, the sub reel rib 6a blocks water from the outside, and the main seal. The rib 5a ensures complete water stoppage.

  However, when the main seal rib 5a is pressed inward by the burring Pa, the large diameter as shown by the arrow in FIG. 5 due to the reaction force that the inner peripheral surface of the grommet 1 is pressed against the outer surface of the wire harness W / H. Stress is generated in a direction in which the side wall 6 is separated from the vehicle body panel P. Under normal conditions of use, there is still no problem with water stoppage, but when an unexpected external force is applied to grommet 1 or when it is used under more severe conditions, the stress shown in FIG. 5 increases. It is conceivable that the grommet 1 is deformed and the contact pressure of the sub seal rib 6a to the vehicle body panel P is weakened.

In JP 2002-369351 A, JP 7-296660 A, and the like, a grommet is provided to the through hole by providing an annular recess in the inner peripheral wall corresponding to the position of the vehicle body locking groove (mounting groove). Although the grommet which fits even if it inclines and the water stop function is ensured is proposed, it does not change that stress as shown by the arrow of FIG. 5 cannot be applied to a large diameter side wall.
JP 2002-369351 A JP-A-7-296660

  This invention is made | formed in view of the said problem, and makes it a subject to provide the grommet which can ensure water-stopping performance stably also on severe conditions.

In order to solve the above-mentioned problems, the present invention has a structure in which a diameter-enlarging cylinder part is continuous with one end of the diameter-cylinder part, and a vehicle body locking groove is annularly formed on an outer peripheral part close to the opening tip side of the other end of the diameter-enlarging cylinder part. In addition, the inner diameter of the enlarged-diameter cylindrical portion and the inner diameter of the smaller-diameter cylindrical portion are substantially the same, and an electric wire group of a wire harness routed to the automobile passes through the opening end of the enlarged-diameter cylindrical portion from the small-diameter cylindrical portion. A grommet that is penetrated and fitted to the vehicle body panel by fitting the periphery of the through hole of the vehicle body panel into the vehicle body locking groove,
The vehicle body locking groove has a bottom wall on which a main seal rib that is pressed against a burring protruding from the periphery of the through hole of the vehicle body panel, and a sub seal rib that is pressed on the periphery of the through hole of the vehicle body panel. A large-diameter side wall provided, and a small-diameter side wall facing the large-diameter side wall, wherein the bottom wall has a groove for stress absorption recessed from a corner contacting the large-diameter side wall; There is provided a grommet characterized in that a reinforcing rib that suppresses stress deformation of the large-diameter side wall is provided on a front end surface surrounding an opening end of the portion.

With the above configuration, even if the peripheral edge of the through hole of the vehicle body panel presses the main seal rib of the vehicle body locking groove and stress is generated on the bottom wall, stress transmission to the large-diameter side wall is blocked by the gap due to the stress absorbing groove. In addition, the contact pressure between the sub seal rib on the large-diameter side wall and the outer surface of the vehicle body panel is prevented from being weakened, and the water stop performance can be stably secured.
Further, since the reinforcing rib is provided on the front end surface surrounding the opening end of the enlarged diameter cylindrical portion, that is, the outer surface opposite to the vehicle body locking groove 4 of the large diameter side wall, the direction in which the large diameter side wall separates from the vehicle body panel. Therefore, the adhesiveness between the sub seal rib and the vehicle body panel is always ensured, and the water stoppage is further improved.

  As is clear from the above description, according to the present invention, even if the peripheral hole of the through hole of the vehicle body panel strongly presses the main seal rib of the vehicle body locking groove and stress is generated on the bottom wall, the stress absorbing groove The transmission of stress to the large-diameter side wall is blocked, and the reinforcing rib is provided on the tip surface surrounding the open end of the large-diameter cylindrical portion, so that the large-diameter side wall is prevented from being deformed away from the vehicle body panel. Therefore, even under severe usage conditions, deformation of the grommet is suppressed, and water stoppage is improved.

Embodiments of the present invention will be described with reference to the drawings.
The grommet 10 is integrally formed of rubber, and has a small-diameter cylindrical portion 11 in which a rib 11a for pressure contact with a wire harness is projected from an inner peripheral surface, and the conical shape continuously expands to the small-diameter cylindrical portion 11. The large-diameter cylindrical portion 12 is provided, and a vehicle body locking groove 14 is annularly recessed in the outer peripheral surface of the large-diameter cylindrical portion 12 on the large-diameter side. Further, the inner peripheral surface of the small diameter cylindrical portion 11 and the inner peripheral surface of the large diameter cylindrical portion 12 have the same continuous inner diameter.

  As shown in FIG. 2, the vehicle body locking groove 13 includes a bottom wall 14 from which a main seal rib 14 a is projected, a large diameter side wall 16 from which a sub seal rib 16 a is projected, and a small diameter side wall that faces the large diameter side wall 16. 15, and a stress absorbing groove 17 is formed in the bottom wall 14 at a corner in contact with the large-diameter side wall 16. As shown in FIGS. 2 and 3, a plurality of reinforcing ribs 19 are provided at intervals in the circumferential direction on the distal end surface 18 surrounding the open end of the enlarged diameter cylindrical portion 12.

Next, attachment of the grommet 10 to the vehicle body panel P will be described.
First, the wire harness to be routed in the automobile is passed through the small diameter cylindrical portion 11 of the grommet 10 through the open end 20 of the enlarged diameter cylindrical portion 12 so that the outer surface of the wire harness W / H is in close contact with the inner peripheral surface of the grommet 1. The wire harness and the grommet 10 are fixed by tape-wrapping at the distal end side of the small diameter cylindrical portion 11.

  Next, when the grommet 10 covered with the wire harness as described above is inserted into the through-hole H of the vehicle body panel P from the small-diameter cylindrical portion 11 side, the small-diameter side wall 15 is deformed so as to be crushed inward, and the through-hole H is formed. The burring Pa on the periphery of the through hole H is fitted into the vehicle body locking groove 4, and the grommet 10 is attached to the vehicle body panel P. In the vehicle body locking groove 13, the main seal rib 14 a is crushed by the burring Pa, and the sub seal rib 16 a is crushed by the outer surface of the vehicle body panel P to double stop water from the outside. .

At this time, the burring Pa projecting from the periphery of the through hole H of the vehicle body panel P presses the main seal rib 14a, so that the inner peripheral surface of the grommet 10 is pressed against the outer surface of the wire harness W / H. 2 is generated in the vicinity of the bottom wall 14, but the stress is blocked by the gap due to the stress absorbing groove 17 without being transmitted to the large-diameter side wall 16, and the sub seal rib 16 a and the vehicle body panel It is possible to prevent the large-diameter side wall 16 from being tilted in the direction in which the contact pressure with P is weakened. Further, since the plurality of reinforcing ribs 19 are erected on the front end surface 18 surrounding the open end 20 of the enlarged diameter cylindrical portion 12, the large diameter side wall 16 is prevented from warping in the direction away from the vehicle body panel P. The
Therefore, the adhesion between the sub seal rib 16a and the outer surface of the vehicle body panel P is maintained, and the water stopping performance can be stably secured.

It is sectional drawing of the grommet of embodiment of this invention. It is principal part sectional drawing of a grommet. It is a rear view of a grommet. It is sectional drawing of the grommet of a prior art example. It is principal part sectional drawing of the grommet of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Grommet 11 Small diameter cylinder part 12 Large diameter cylinder part 13 Car body latching groove 14 Bottom wall 14a Main seal rib 15 Small diameter side wall 16 Large diameter side wall 16a Sub seal rib 17 Stress absorbing groove 18 End face 19 Reinforcement rib 20 Open end H Through hole P Body panel Pa burring

Claims (1)

The enlarged-diameter cylindrical portion is continuous with one end of the small-diameter cylindrical portion, and an annular vehicle body locking groove is provided in the outer peripheral portion close to the opening tip side of the other end of the enlarged-diameter cylindrical portion, and the enlarged-diameter cylindrical portion The inner diameter of the small diameter cylindrical portion is substantially the same as the inner diameter of the small diameter cylindrical portion, and an electric wire group of a wire harness routed in the automobile is penetrated from the small diameter cylindrical portion through the opening end of the large diameter cylindrical portion. A grommet that is fitted to the vehicle body panel with the periphery of the through hole fitted therein,
The vehicle body locking groove has a bottom wall on which a main seal rib that is pressed against a burring protruding from the periphery of the through hole of the vehicle body panel, and a sub seal rib that is pressed on the periphery of the through hole of the vehicle body panel. A large-diameter side wall provided, and a small-diameter side wall facing the large-diameter side wall, wherein the bottom wall has a groove for stress absorption recessed from a corner contacting the large-diameter side wall; A grommet characterized in that a reinforcing rib that suppresses stress deformation of the large-diameter side wall is provided on a front end surface surrounding the opening end of the portion.

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