JP2016159891A - Grommet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a grommet capable of facilitating mold releasing after molding and exerting high sound insulation performance.SOLUTION: An elastic material-made grommet 10 has: a large diameter cylindrical part 11 comprising a panel engagement part 12 on an outer periphery; two small diameter cylindrical parts 13, 14 disposed at both sides of the large diameter cylindrical part in an axial direction Y and tightly fitted to the outer periphery of an electric wire W, respectively; and two annular connected shield walls 15, 16 in which an outer peripheral edge is joined to the large diameter cylindrical part and an inner peripheral edge is joined to the small diameter cylindrical part. Plural platy noise barriers 20 axially extending and disposed radially leaving a space in a circumferential direction are integrally formed inside.SELECTED DRAWING: Figure 1

Description

  The present invention, for example, when a wire harness (electric wire) is routed so as to penetrate a vehicle body panel (such as a dash panel or a rear panel) that partitions a vehicle interior side and a vehicle exterior side, is provided. It is related with the grommet used by fitting in the through-hole of a panel in order to protect this, or in order to ensure quietness, airtightness, etc. of a vehicle interior.

  This type of grommet is attached to a through-hole provided in a vehicle body panel that partitions the interior side and the exterior side of a vehicle to ensure airtightness and quietness in the vehicle interior. Recently, quietness in the passenger compartment has been strongly demanded, and grommets with improved sound insulation performance have been developed.

FIG. 6 shows a configuration example of a grommet in which an annular sound insulation wall is integrally provided in order to improve sound insulation performance (see, for example, Patent Document 1).
The grommet 101 includes a large-diameter cylindrical portion 111 having a panel engagement groove 112 that engages with an inner peripheral edge of the through hole Pa of the vehicle body panel P, and a first small-diameter cylindrical portion through which an electric wire (wire harness) W is inserted. 113 and the second small-diameter cylindrical portion 114, the thick wall 115 that couples the first small-diameter cylindrical portion 113 and the large-diameter cylindrical portion 111, the outer peripheral edge is coupled to the large-diameter cylindrical portion 111, and the inner peripheral edge is the second small-diameter cylindrical portion. 114, a thin tubular shielding wall 116 (funnel-shaped) coupled to 114, and an annular sound insulation wall 117 projecting on the inner periphery of the coupling shielding wall 116 near the large-diameter cylindrical portion 111. Have. The first small-diameter cylindrical portion 113 and the second small-diameter cylindrical portion 114 are formed so as to be tightly fitted to the outer periphery of the electric wire W finally.

  When this grommet 101 is attached to the through hole Pa of the panel P, the first small diameter cylindrical portion 113 and the electric wire W are wound and fixed with a tape, and the second small diameter cylindrical portion 114 and the electric wire W are also fixed with a tape. Thereby, two sealed spaces 118 and 119 partitioned by the sound insulation wall 117 are secured inside the grommet 101. Therefore, the sound insulation is enhanced by the presence of the sound insulation wall 117 and the sealed spaces 118 and 119.

FIG. 7 is a schematic explanatory view for explaining a method of releasing the grommet 101 from the internal mold 140 after the grommet 101 of FIG. 6 is molded.
When releasing the molded grommet 101 from the internal mold 140, air N is blown from, for example, the second small-diameter cylindrical portion 114, which is an opening on one end side of the grommet 101, and the grommet 101 is removed by the force of air. The diameter is forcibly expanded as indicated by an arrow B1. Then, with the diameter expanded, the grommet 101 is released from the internal mold 140 by pulling the grommet 101 to one side in the axial direction indicated by the arrow B2.

  However, when the annular sound insulation wall 117 is integrally provided inside the grommet 101, the sound insulation wall 117 exists in a direction orthogonal to the drawing direction (axial direction), and therefore air wraps around to the opposite side of the sound insulation wall 117. In addition, the sound insulation wall 117 obstructs the extraction, making it difficult to release. For example, the longer the length H1 of the sound insulation wall 117, the more difficult the mold release becomes, so the length of the sound insulation wall 117 is limited. However, if the length H1 of the sound insulation wall 117 is limited, the sound insulation performance may be affected.

  Moreover, in the grommet which fills the inside with the waterproof filler, as shown in FIGS. 8A and 8B, a funnel-like (tapered tubular) connecting the large-diameter cylindrical portion 211 and the small-diameter cylindrical portion 213. Inside the connection shielding wall 215, there is a grommet 201 in which a plurality of ribs 217 for increasing the adhesion to the filler are arranged radially (see, for example, Patent Document 2). However, since the rib 217 in this case is for improving the adhesiveness, it does not extend to the position of the large-diameter cylindrical portion 211 that fits into the through hole of the panel. Therefore, it does not aim at sound insulation. In particular, it is not possible to ensure sufficient sound insulation against sound from a direction perpendicular to the insertion direction of the electric wire.

JP 2005-324613 A JP-A-7-21864

  As described above, the conventional grommet 101 shown in FIG. 6 has a problem in releasability at the time of molding, and if the length of the soundproof wall is limited for the improvement, there is a possibility that the sound insulation performance is adversely affected. was there. In addition, the conventional grommet 201 shown in FIG.

  This invention is made | formed in view of the situation mentioned above, The objective is to provide the grommet which can perform the mold release at the time of shaping | molding easily, and can exhibit high sound-insulation performance. .

In order to achieve the above-described object, the grommet according to the present invention is characterized by the following (1) and (2).
(1) A large-diameter cylindrical portion having a panel engaging portion that engages with the inner peripheral edge of the through hole of the panel on the outer periphery;
A small-diameter cylindrical portion that is disposed on both sides in the axial direction of the large-diameter cylindrical portion and closely fits to the outer periphery of the electric wire that is passed through the through hole;
An outer peripheral edge is coupled to the large-diameter cylindrical portion and an inner peripheral edge is coupled to the small-diameter cylindrical portion, and two annular rings that respectively shield the annular spaces between the large-diameter cylindrical portion and the small-diameter cylindrical portions. A connecting shielding wall;
A grommet having
A plurality of plate-like sound insulation walls extending in the axial direction and radially arranged at intervals in the circumferential direction are formed inside one of the connection shielding walls, and the other connection shielding wall in each of the sound insulation walls. The axial end located on the side is extended to at least an inner position corresponding to the panel engaging portion of the large-diameter cylindrical portion.
(2) In the grommet configured as described in (1) above,
The outer edge of each sound insulation wall is coupled to the inner wall surface of the grommet from one of the two coupling positions of the two small diameter cylindrical portions and the connection shielding wall, and the inner edge of each sound insulation wall is the two small diameters. It is arranged at a position in contact with or close to the outer periphery of the electric wire inserted through the cylindrical portion.

According to the grommet having the configuration (1), the sound insulation effect can be improved with respect to the sound entering in a direction orthogonal to the sound insulation wall or in an oblique direction. In addition, since the sound insulation wall partitions the inner space of the grommet into a plurality in the circumferential direction, propagation of the air vibration in the circumferential direction can be reduced, and a sound insulation effect can be achieved thereby. In other words, transmitted sound enters the grommet from various directions, and high sound insulation can be exhibited by reducing these transmitted sounds. Further, since each sound insulating wall is formed along the axial direction (the pulling direction at the time of mold release), it does not obstruct the mold release when the sound insulating wall is formed integrally with the connecting shielding wall. Therefore, the molded grommet can be easily released from the internal mold, and productivity can be improved.
According to the grommet having the configuration (2), most of the internal space of the grommet around the electric wire can be partitioned in the circumferential direction by the sound insulating wall. That is, the air layer between the sound insulation walls can be kept sealed. Therefore, the propagation of sound in the adjacent air layer can be reduced, and the sound insulation can be improved.

  According to the present invention, mold release at the time of molding can be easily performed and high sound insulation performance can be exhibited.

  The present invention has been briefly described above. Further, the details of the present invention will be further clarified by reading through a mode for carrying out the invention described below (hereinafter referred to as “embodiment”) with reference to the accompanying drawings. .

FIG. 1 is a perspective view in which the grommet according to the embodiment of the present invention is broken at a position off the axial center. FIG. 2 is a longitudinal sectional view at a position off the axis center of the grommet. FIG. 3 is a longitudinal sectional view at a position passing through the axial center of the grommet. 4 is a cross-sectional view taken along the line IV-IV in FIG. 5 is a cross-sectional view taken along line VV in FIG. FIG. 6 is a cross-sectional view showing a configuration example of a conventional grommet with improved sound insulation. FIG. 7 is a schematic explanatory view for explaining a mold release method after forming the grommet of FIG. 8A and 8B are diagrams showing a configuration example of another conventional grommet, in which FIG. 8A is a perspective view and FIG. 8B is a cross-sectional view.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view broken away at a position off the axial center of the grommet of the embodiment, FIG. 2 is a longitudinal sectional view at a position off the axial center of the grommet, and FIG. 3 is a position passing through the axial center of the grommet. 4 is a cross-sectional view taken along the line IV-IV of FIG. 3, and FIG. 5 is a cross-sectional view taken along the line V-V of FIG.

  As shown in FIGS. 1 to 3, this grommet 10 includes an electric wire (wire harness) W that passes through a through hole Pa provided in a vehicle body panel P that partitions a vehicle interior side (indoor side) IN and an outdoor side OUT of an automobile. It is attached between the through hole Pa of the panel P, and is integrally formed of an elastic material such as rubber or elastomer.

  The grommet 10 includes a thick-walled large-diameter cylindrical portion 11 having an annular panel engaging portion 12 that engages with the inner peripheral edge of the through hole Pa of the panel P on the outer periphery, and both sides of the large-diameter cylindrical portion 11 in the axial direction. Two small-diameter cylindrical portions 13 and 14 that are closely fitted to the outer periphery of the electric wire W that is passed through the through hole Pa, and the outer peripheral edge is coupled to the large-diameter cylindrical portion 11 and the inner peripheral edge is the small-diameter cylindrical portion. 13 and 14, and two tapered cylindrical connecting shielding walls 15 and 16 that respectively shield the annular spaces between the large-diameter cylindrical portion 11 and the small-diameter cylindrical portions 13 and 14. .

  As shown in FIGS. 1 to 5, the inner peripheral surface of the grommet 10 has a plurality of plate-like shapes each extending along the axial direction Y and radially arranged at intervals in the circumferential direction. The sound insulation wall 20 is integrally formed. In the illustrated example, eight sound insulating walls 20 are provided at equal intervals in the circumferential direction. The number of the sound insulating walls 20 is arbitrary as long as it is two or more, and it is desirable that the sound insulating walls 20 be arranged at equal intervals in the circumferential direction if possible.

  The outer edge 21 of each sound insulating wall 20 extends from the coupling position between the small-diameter cylindrical portion 14 disposed on the outdoor side OUT and the connecting shielding wall 16 to the coupling position between the small-diameter cylindrical portion 13 disposed on the indoor side IN and the coupling shielding wall 15. The grommet 10 is coupled to the inner wall surface. Further, the inner edge 22 of each sound insulating wall 20 is arranged at a position in contact with or close to the outer periphery of the electric wire W inserted through the small diameter cylindrical portions 13 and 14.

  Since the sound insulating wall 20 is formed in this manner, most of the internal space of the grommet 10 around the electric wire W is partitioned in the circumferential direction by the sound insulating wall 20, and the air layers S between the sound insulating walls 20 are almost sealed. Will be kept. Therefore, the propagation of sound between the air layers S adjacent in the circumferential direction can be reduced, and the sound insulation can be improved. Further, since the sound insulating wall 20 serves as a reinforcing rib for both the connecting shielding walls 15 and 16, vibration of the connecting shielding walls 15 and 16 can be suppressed. Therefore, the sound insulation effect with respect to the transmitted sound can be increased also in this respect.

  Moreover, as shown in FIGS. 1-3, the four ribs 23 are provided in the outer periphery of the small diameter cylinder part 13 located in the indoor side IN at equal intervals in the circumferential direction. Each rib 23 has a peripheral edge coupled to a region extending from the outer surface of the small-diameter cylindrical portion 13 positioned on the indoor side IN to the outer surface on the radially inner peripheral side of the connection shielding wall 15. The peripheral side portion and the small diameter cylindrical portion 13 are reinforced. Each rib 23 is formed with a slit 24 communicating with the inner periphery of the small-diameter cylindrical portion 13 in the middle portion in the thickness direction of the rib 23. Due to the presence of the slit 24, the small-diameter cylindrical portion 13 can be freely expanded and contracted according to the outer diameter of the electric wire W. In addition, the slit 24 is extended and provided in the sound insulation wall 20 corresponding to the position where the rib 23 was provided.

  When this grommet 10 is used, the electric wire W is inserted into the small-diameter cylindrical portion 13 on the indoor side IN and the small-diameter cylindrical portion 14 on the outdoor side OUT, and the small-diameter cylindrical portion 14 on the outdoor side OUT is connected with the electric wire W and a tape or a band. Fix it. By doing so, a plurality of air layers S partitioned by the sound insulation wall 20 in the circumferential direction are secured inside the grommet 10.

  Thereafter, the grommet 10 is inserted into the through hole Pa of the panel P, and the panel engaging portion 12 on the outer periphery of the large diameter cylindrical portion 11 of the grommet 10 is engaged with the inner peripheral edge of the through hole Pa of the panel P. This completes the installation.

  In the grommet 10 having the above configuration, since the sound insulating wall 20 is formed along the axial direction, as shown in FIG. 5, the sound insulating effect on the sound D entering the direction perpendicular to or oblique to the sound insulating wall 20 Can be improved. Moreover, since the sound insulation wall 20 partitions the internal space of the grommet 10 into a plurality of air layers S in the circumferential direction, propagation of air vibration in the circumferential direction can be reduced, and a sound insulation effect can be achieved thereby.

  In particular, in this grommet 10, since most of the internal space of the grommet 10 around the electric wire W can be partitioned in the circumferential direction by the sound insulating wall 20, the air layers S between the sound insulating walls 20 can be kept in a sealed state. Therefore, the propagation of sound between the adjacent air layers S can be reduced, and the sound insulation can be further improved.

  In other words, transmitted sound enters the grommet 10 from various directions, but by reducing these transmitted sounds, high sound insulation can be exhibited.

  Moreover, since each sound insulation wall 20 is formed along the axial direction (the pulling direction at the time of mold release), it does not interfere with the die cutting. The die cutting method is the same as the method described with reference to FIG. Therefore, the molded grommet 10 can be easily released from the internal mold, and productivity can be improved.

  In addition, this invention is not limited to embodiment mentioned above, A deformation | transformation, improvement, etc. are possible suitably. In addition, the material, shape, dimensions, number, arrangement location, and the like of each component in the above-described embodiment are arbitrary and are not limited as long as the present invention can be achieved.

  For example, in the above-described embodiment, each of the sound insulation walls 20 has a small diameter cylindrical portion 13 whose outer edge 21 is disposed on the indoor side IN from the coupling position of the small diameter cylindrical portion 14 disposed on the outdoor side OUT and the connecting shielding wall 16. Are connected to the inner wall surface of the grommet 10 up to the connection position of the connecting shield wall 15 and the inner edge 22 of the grommet 10 is formed in such a size as to be in contact with or close to the outer periphery of the electric wire W. However, it is not necessarily limited to that.

  That is, each of the sound insulation walls 20 is formed on the inner periphery of one of the two connection shielding walls 15 and 16, which is disposed on the outdoor side OUT that is a noise environment, on the indoor side IN of each sound insulation wall 20. If the end in the axial direction Y that is positioned extends at least to the position on the inner peripheral side corresponding to the panel engagement portion 12 of the large-diameter cylindrical portion 11, a temporary sound insulation effect can be expected.

  In the above embodiment, if the air layer S partitioned by the sound insulation wall 20 is filled with a sound absorbing material, the sound insulation performance can be further improved.

Here, the features of the above-described grommets according to the present invention are summarized and listed in the following [1] to [2], respectively.
[1] A large-diameter cylindrical portion (11) having a panel engagement portion (12) engaged with the inner peripheral edge of the through hole (Pa) of the panel (P) on the outer periphery;
A small-diameter cylindrical portion (13, 14) disposed on both sides in the axial direction (Y) of the large-diameter cylindrical portion (11) and closely fitting to the outer periphery of the electric wire (W) passed through the through-hole (Pa); ,
An outer peripheral edge is coupled to the large diameter cylindrical portion (11), and an inner peripheral edge is coupled to the small diameter cylindrical portion (13, 14). Two annular shielding walls (15, 16) each shielding the annular space between
A grommet (10) having
A plurality of plate-like sound insulation walls (20) extending along the axial direction (Y) and radially arranged at intervals in the circumferential direction are formed inside one of the connection shielding walls (15), The end portion in the axial direction (Y) located on the other connecting shielding wall (15) side of each sound insulating wall (20) corresponds to at least the panel engaging portion (12) of the large diameter cylindrical portion (11). Grommet (10), characterized by extending to an inner position.
[2] Grommet from one side to the other of two coupling positions of the outer edge (21) of each sound insulation wall (20) by the two small diameter cylindrical portions (13, 14) and the connection shielding wall (15, 16) The inner edge (22) of each sound insulation wall (20) is in contact with or close to the outer periphery of the electric wire (W) inserted through the two small diameter cylindrical portions (13, 14). The grommet (10) according to the above [1], wherein the grommet (10) is arranged on the grommet.

DESCRIPTION OF SYMBOLS 10 Grommet 11 Large diameter cylinder part 12 Panel engaging part 13,14 Small diameter cylinder part 15,16 Connection shielding wall 20 Sound insulation wall 21 Outer edge 22 Inner edge P Panel Pa Through-hole W Electric wire (wire harness)
Y axis direction OUT Outdoor side IN Indoor side

Claims (2)

A large-diameter cylindrical portion provided on the outer periphery with a panel engaging portion that engages with the inner peripheral edge of the through hole of the panel;
A small-diameter cylindrical portion that is disposed on both sides in the axial direction of the large-diameter cylindrical portion and closely fits to the outer periphery of the electric wire that is passed through the through hole;
An outer peripheral edge is coupled to the large-diameter cylindrical portion and an inner peripheral edge is coupled to the small-diameter cylindrical portion, and two annular rings that respectively shield the annular spaces between the large-diameter cylindrical portion and the small-diameter cylindrical portions. A connecting shielding wall;
A grommet having
A plurality of plate-like sound insulation walls extending in the axial direction and radially arranged at intervals in the circumferential direction are formed inside one of the connection shielding walls, and the other connection shielding wall in each of the sound insulation walls. A grommet characterized in that an axial end located on the side extends to at least an inner position corresponding to the panel engaging portion of the large diameter cylindrical portion.   The outer edge of each sound insulation wall is coupled to the inner wall surface of the grommet from one of the two coupling positions of the two small diameter cylindrical portions and the connection shielding wall, and the inner edge of each sound insulation wall is the two small diameters. The grommet according to claim 1, wherein the grommet is disposed at a position in contact with or close to an outer periphery of the electric wire inserted through the cylindrical portion.

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