JP2012050307A - Grommet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain water shut-off performance even when burring varies, in a grommet externally mounted to a wire harness and fitted to a through hole with the burring of a vehicle body.SOLUTION: An annular recess for locking the vehicle body fitted to the inner peripheral face of the through hole with the burring is provided on the outer peripheral face of a cylindrical part surrounding a wire harness through hole. A seal lip is protruded to be inclined toward one side face in an intermediate part of the bottom face of the annular recess, and the bottom face of the annular recess on the inclined side of the seal lip is dug from a root of the seal lip to form a deep bottom part deeper than the other bottom face on the non-inclined side, so as to make the seal lip easily tilt.

Description

  TECHNICAL FIELD The present invention relates to a grommet, and more specifically, it is externally mounted on a wire harness that is routed in an automobile, and is attached to a through hole formed in a vehicle body to achieve waterproofing, dustproofing, and sound insulation from the engine room or the outside of the vehicle to the vehicle interior. .

  Of the through holes drilled in the vehicle body, in the case of a relatively large through hole, in many cases, a through hole with a burring in which a burring protrudes from the periphery of the through hole is maintained in order to maintain the strength of the periphery of the through hole. Since the wire harness routed from the engine room to the vehicle compartment through the through hole provided in the dash panel is a large-diameter wire harness, the through hole provided in the dash panel is often a through hole with a burring.

As a grommet to be attached to this kind of through hole with a burring, for example, Japanese Patent Application Laid-Open No. 2009-17682 proposes a grommet 100 shown in FIGS.
The grommet 100 includes an annular concave groove 101 provided on the outer peripheral surface. The burring 112 of the through hole 111 provided in the vehicle body 110 is dropped into the concave groove 101, and the seal lip 102 protruding from the bottom surface of the concave groove 101 is burring. The seal lip 103 is pressed against the vehicle body 110 at the periphery of the through-hole 111 while pressing against the inner surface side of 112.
At that time, the protruding amount of the sealing lip 102 protruding from the bottom surface of the groove 101 of the grommet 100 is made relatively high so that the sealing lip 102 is pushed and bent by the burring 112 at the contact surface with the burring 112, Even when the gap between the burring 112 and the concave groove 101 is maximized, the seal lip 102 comes into contact with the burring 112 so that sealing can be performed.

JP 2009-17682 A

A through hole with a burring formed by punching a body (steel plate) of a vehicle body is difficult to maintain high dimensional accuracy and shape accuracy. For example, as shown in FIG. 10 (A), the refracting angle θ of the burring 112 refracting from the periphery of the through hole 111 of the vehicle body 110 is set at a right angle, but as shown in FIGS. 10 (B) and (C). In many cases, it is not bent at a right angle. Further, the smaller radius (R) at the base of the burring 112 is better, but when the radius becomes larger, a large dimensional error occurs in the inner diameter surrounded by the burring 112. That is, as shown in FIG. 10B, when the angle θ becomes an acute angle and the radius is small, the tip of the burring 112 opens outwardly and the inner diameter d surrounded by the burring 112 increases toward the tip of the burring.
Therefore, a gap is generated between the inner peripheral surface of the burring 112 and the seal lip 102 of the grommet. If the protruding amount of the seal lip 102 is increased in order to eliminate the gap, the seal lip 102 can be brought into contact with the burring 112.
On the other hand, as shown in FIG. 10C, when the angle θ becomes obtuse, the inner diameter d of the burring 112 gradually decreases toward the tip. In this case, when the protruding amount of the seal lip 102 is increased, the pressing amount of the seal lip 102 is increased, the resistance against the burring 112 is increased, and the grommet 100 is deformed as shown by the dotted line in the figure, which causes water leakage. Prone.

  In the grommet shown in FIG. 9, the protruding amount of the seal lip projecting from the bottom surface of the concave groove is increased so that the seal lip contacts the inner surface of the burring even when the inner diameter of the burring is increased. However, as described above, if the protruding amount of the seal lip is increased, the amount of collapse of the seal lip increases when the inner diameter of the burring is small. In that case, the grommet shown in FIG. 9 is not configured to absorb even if the amount of fall of the seal lip increases, so that the protruded seal lip tends to float up from the burring and the entire grommet is deformed. However, there is a problem that the sealing performance is likely to be lowered.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a grommet that can satisfy the sealing performance even if the dimensional accuracy of the through hole with a burring formed in the vehicle body has a large variation.

In order to solve the above-mentioned problem, the present invention is a grommet molded from rubber or elastomer that is fitted and fixed to a wire harness and is attached to a through-hole with a burring formed in a vehicle body,
An annular recess for locking the vehicle body fitted to the inner periphery of the through hole with a burring is provided on the outer peripheral surface of the cylindrical portion surrounding the wire harness through hole, and a seal lip is provided on one side of the bottom of the annular recess. The bottom surface of the annular concave portion on the inclined side of the seal lip is formed as a deep bottom portion that is dug from the root of the seal lip and deeper than the other bottom surface on the non-inclined side; A grommet characterized by making the lip easy to collapse is provided.

  As described above, in the grommet of the present invention, the protrusion amount of the seal lip provided on the bottom surface of the annular recess for locking the vehicle body is made large in order to follow the dimensional variation of the burring, as in Patent Document 1. When the lip comes into contact with the inner peripheral surface of the burring and is pressed, it tilts in one direction so that it falls easily, and the depth of the bottom surface of the annular recess on the inclined side is increased to make the inner diameter of the burring small and the amount of fall of the seal lip It is possible to fall down without resistance even if it becomes large. Accordingly, the seal lip can be easily tilted in the inclined direction according to the diameter of the burring, and the burring inner circumferential surface and the seal lip can be brought into contact with each other with a required surface pressure to improve the sealing performance.

It is preferable that the inner peripheral surface of the bottom wall facing the bottom surface is thickened and thickened by an amount corresponding to the digging amount of the bottom surface on the inclined direction side of the seal lip.
When the bottom surface of the annular recess is dug deeper, the thickness becomes thinner than the thickness on the non-inclined side, and a portion with low rigidity and easily breaks is generated. The thick portion may be only the portion facing the portion having the deepened bottom surface, or the entire bottom portion of the annular recess may be thick.

  A second seal lip projects from the bottom surface of the annular recess from the bottom surface on the non-inclined side of the seal lip, and the second seal lip has a protruding height lower than that of the inclined seal lip and is inclined. It is preferable to make it protrude perpendicularly | vertically with respect to a bottom face.

  The second seal lip is a seal lip protruding from the bottom surface of the annular recess of the conventional grommet. The second seal lip just contacts the inner peripheral surface of the burring when the dimensional accuracy of the burring is high. Therefore, in this case, since the two first and second seal lips are in contact with the inner peripheral surface of the burring, the sealing performance can be improved, and the reliability of the grommet water-stopping performance can be improved. .

  Furthermore, a first small protrusion that protrudes toward the burring insertion side may be provided at the protruding tip of the first seal lip, and a second small protrusion may be provided at a position where a gap is formed from the first small protrusion to the root side. . The small protrusion is pressed against the lower surface of the burring inserted into the annular recess, and the sealing performance can be improved.

  The grommet according to the present invention having the above-described configuration makes the seal lip to be in contact with the inner peripheral surface of the burring incline easily by tilting even if the burring size varies, and deepens the bottom surface on the inclined side by digging. Therefore, even if the amount of the seal lip falls down, it can be pushed down without difficulty. Therefore, the sealing performance can be secured by the contact pressure with the burring, and there is an advantage that the entire grommet can be prevented from being deformed because excessive resistance is not generated.

The grommet of 1st Embodiment of this invention is shown, (A) is a perspective view, (B) is sectional drawing. It is a principal part expanded sectional view. (A) (B) (C) is sectional drawing which shows the contact state of a burring and a seal lip. (A) (B) is sectional drawing which shows the 1st, 2nd modification of 1st Embodiment. (A) (B) (C) is sectional drawing which shows the effect | action of a 1st, 2nd modification. (A) and (B) are the principal part expanded sectional views of 2nd Embodiment. (A) and (B) are the principal part expanded sectional views of 3rd Embodiment. (A) and (B) are the principal part expanded sectional views of 4th Embodiment. (A) (B) is sectional drawing which shows a prior art example. (A), (B), and (C) are drawings for explaining problems.

Hereinafter, embodiments of the grommet of the present invention will be described.
1 to 3 show a grommet according to the first embodiment.
A wire harness W / H is passed from an engine room (X) to a vehicle compartment (Y) through a through-hole 111 with a burring provided in a vehicle body 110 formed of a dash panel of an automobile, and a grommet 1 is attached to the wire harness W / H. The grommet 1 is attached and sealed against the inner peripheral surface of the burring 112 for waterproofing, dustproofing and soundproofing from the engine room (X) to the vehicle compartment.

The grommet 1 is made of a rubber or elastomer molded product. The grommet 1 includes a first small-diameter cylindrical portion 2 through which the wire harness W / H is closely inserted, a large-diameter cylindrical portion 3 continuous to one end of the first small-diameter cylindrical portion 2, and a large diameter-enlarged cylindrical portion 3. A thin-walled closed portion 4 that closes the distal end on the diameter side, and a second small-diameter cylindrical portion 5 that includes a pair of semi-cylindrical portions that protrude from the periphery of a hole provided in the central portion of the slit provided in the diameter direction of the thin-walled closed portion 4 Prepare.
An annular recess 6 for locking the vehicle body is provided on the outer peripheral surface on the large-diameter side of the expanded diameter cylindrical portion 3.
The annular recess 6 is for dropping and locking the burring 112 and fixing the grommet 1 to the through hole 111 of the vehicle body 110.

  As shown in an enlarged view in FIG. 2, the annular recess 6 includes a large-diameter side surface 11 and an inclined wall-side side surface 12 that sandwich the bottom surface 10 of the annular recess 6. The side surface 12 is composed of the side surface of the inclined wall 8 continuing to the first small-diameter cylindrical portion 2. The large-diameter side surface 11 protrudes from the other side surface 12 in the outer diameter direction.

  The axial width L1 of the bottom surface 10 of the annular recess 6 is substantially equal to the length corresponding to the length L2 from the vehicle body 110 to the tip of the burring 112. The position S of the bottom surface 10 corresponds to the inner diameter of the burring 112 so that the inner peripheral surface 112a of the burring 112 and the bottom surface 10 can be brought into contact with each other.

  A seal lip 15 protrudes from an intermediate position in the width direction of the bottom surface 10. The projecting dimension h1 (dimension in the direction perpendicular to the bottom surface 10) of the seal lip 15 is 2.0 mm to 2.5 mm, and the average thickness t is 0.8 mm to 1.3 mm. Further, the seal lip 15 is inclined toward the side surface 11, the inclination angle α is 30 ° to 80 °, and the gap C between the protruding end 15 a of the seal lip 15 and the side surface 11 is 1 mm to 3 mm.

  The bottom surface 10 on the inclined side of the seal lip 15 has a deep bottom portion 16 formed by digging the bottom surface on one side from the base 15b to the side surface 11 of the seal lip 15 from the position S (indicated by a dashed line in FIG. 2). . The other side bottom surface 10a remains at the position S. The digging dimension h2 of the deep bottom portion 16 is defined as t = h2 × 0.9 from the relationship with the thickness t of the seal lip 15. The dimension of the width d of the deep bottom portion 16 is not less than the projecting dimension h1 of the seal lip 15 (d ≧ h1).

  Further, a built-up portion 18 is provided on the inner peripheral surface of the enlarged diameter cylindrical portion 3 corresponding to the deep bottom portion 16. The thickness of the build-up portion 18 corresponds to the amount of digging of the deep bottom portion 16, and is therefore equivalent to the strength of the other side bottom surface 10a. Thereby, the grommet is prevented from being deformed by providing the deep bottom portion 16.

  The large-diameter side surface 11 sandwiching the bottom surface 10 of the annular recess 6 is a protruding side surface of the burring 112, the outer peripheral portion of the side surface 11 is a protruding portion 11 a protruding toward the annular recess 6, and the inner peripheral portion is a recess 13. . The side surface 12 on the inclined wall side is an inclined wall whose outer periphery is inclined toward the large diameter side, and the inclined protruding end of the side surface 12 is opposed to the protruding portion 11 a of the side surface 11. Therefore, the opening width L3 of the annular recess 6 is about half of the width L1 of the bottom surface 10 in the axial direction.

  Further, the outer peripheral surface of the enlarged diameter cylindrical portion 3 from the side surface 12 of the annular concave portion 6 to the continuous end with the first small diameter cylindrical portion 2 is directed from the continuous end with the first small diameter cylindrical portion 2 toward the annular concave portion 6. Radial stepped protrusions 20 are provided. In addition, a narrow groove 22 is provided in a triangular portion 21 sandwiched between adjacent stepped protrusions 20 to facilitate bending. Further, a washer hose and a cable opener 24 are projected from the thin wall closing portion 4.

  The grommet 1 penetrates the wire harness W / H in close contact with the first small-diameter cylindrical portion 2, the enlarged-diameter cylindrical portion 3, and the second small-diameter cylindrical portion 5, and the first and second small-diameter cylindrical portions 2, 5 An adhesive tape is wound around and fixed to the outer peripheral surface of the wire harness from the tip.

  When wiring to the automobile, the first small diameter cylindrical portion 2 of the grommet 1 is pushed into the vehicle compartment (Y) from the engine room (X) through the through hole 111 with the insertion side. In that case, it inserts into the through-hole 111 from the small diameter side of the diameter expansion cylinder part 3, and pushes in strongly from the position where the outer diameter of the diameter expansion cylinder part 3 became equivalent to the inner diameter of the through hole 111, The grommets 1 are fixed to the vehicle body 110 by being deformed so as to be reduced in diameter, and dropping and locking the burring 112 protruding from the periphery of the through hole 111 into the annular recess 6. That is, the grommet 1 is locked to the through hole 111 in one motion by simply pushing the grommet 1 into the through hole 111 from the engine room side to the vehicle compartment side. And since the step-shaped protrusion 20 is provided in the outer peripheral surface of the diameter-expanded cylinder part 3, since a contact area with the burring 112 reduces, the insertion force of a grommet can be reduced.

  The details of the operation in which the burring 112 is inserted and locked into the annular recess 6 of the grommet 1 are because the burring 112 protrudes into the engine room (X), so that the outer peripheral surface of the enlarged diameter cylindrical portion 3 of the grommet 1 is the tip side of the burring 112 From the protruding end, and the burring 112 is inserted into the annular recess 6 from the protruding end. When the burring 112 is inserted into the annular recess 6, the inclined tip of the side surface 12 of the annular recess 6 is pressed against the side surface 110 a of the vehicle body 110.

  The inner peripheral surface 112a of the burring 112 dropped into the annular recess 6 faces the bottom surface 10 of the annular recess 6, and the seal lip 15 protruding from the bottom surface 10 is pressed against the burring inner peripheral surface 112a. At that time, the seal lip 15 is made to have a large protruding amount and inclined so that the seal lip 15 and the burring inner circumferential surface 112a are brought into contact with each other even when the burring 112 is uneven. be able to.

  FIG. 3A shows a case where the burring 112 is bent at a right angle with respect to the vehicle body 110 and the burring 112 protrudes straight in a direction perpendicular to the vehicle body 110 with high dimensional accuracy. In this case, the protruding end 15a of the seal lip 15 is pressed by the inner peripheral surface of the burring 112, and the seal lip 15 is slightly tilted toward the deep bottom 16 side. In this state, a set surface pressure is generated on the contact surface between the seal lip 15 and the burring 112.

  As shown in FIG. 3B, when the angle θ of the burring 112 is an acute angle and the inner peripheral surface 112a of the burring 112 is bent outwardly and bent, the inner diameter of the burring 112 is directed toward the protruding side. It is getting bigger gradually. In this case, the inner peripheral surface of the burring 112 abuts with a contact pressure that can ensure a sealing property while slightly tilting the protruding end 15a of the seal lip 15 in the inclined direction.

  On the other hand, as shown in FIG. 3C, when the R angle θ of the burring 112 becomes an obtuse angle and the inner peripheral surface 112a of the burring 112 is bent inwardly and bent, the inner diameter of the burring 112 is directed toward the protruding side. It is getting smaller. In this case, the inner peripheral surface of the burring 112 is inserted while the protruding end 15a of the seal lip 15 is strongly pushed down in the inclined direction, and the seal lip 15 is bent in a u-shape. At that time, since the seal lip 15 falls from the root 15b and the bottom surface in the inclined direction becomes the deep bottom portion 16, the seal lip 15 can be pushed down smoothly by the burring 112, and no great resistance force is generated. Therefore, the seal lip 15 and the inner peripheral surface of the burring 112 can be brought into contact with each other with a required seal pressure without causing almost any deformation in the grommet 1.

  As described above, the inclined lip 15 is provided in the annular recess 6 for locking the vehicle body of the grommet 1 of the present invention, and the bottom of the recessed portion in the inclined direction is provided with the deep bottom portion 16 from the base of the seal lip 15 to provide a seal. The lip 15 is easily tilted in the tilt direction. Therefore, even if the burring 112 is bent at an acute angle or an obtuse angle and there is a large variation in the inner diameter dimension of the burring, the seal lip 15 is pushed down by the inner peripheral surface of the burring 112 without causing a large resistance force and falls smoothly. The waterproof performance of the grommet can be maintained.

FIGS. 4A and 4B show first and second modifications of the first embodiment.
In the first modification of FIG. 4A, a first small protrusion 15 h that protrudes toward the insertion side of the vehicle body 110, that is, the side surface 12 is provided at the protruding end of the seal lip 15.
In the second modification of FIG. 4B, the first small protrusion 15h and the second small protrusion 15i are provided at a position having a dimension of 0.3 to 1.0 mm closer to the root side than the first small protrusion, Two small protrusions are provided.
The first small protrusion 15h and the second small protrusion 15i are both semicircular arc-shaped protrusions of 0.3 mm to 1.0 mmR.

When the first small protrusion 15h is provided as in the first modification, the first small protrusion 15h can be pressed against the lower surface of the burring 112 as shown in FIG.
When the first and second small protrusions 15h and 15i are provided as in the second modification, the first and second small protrusions 15h and 15i are burring 112 as shown in FIGS. It can be pressed against the lower surface of the glass, and the water stoppage can be increased.

6 (A) and 6 (B) show a grommet according to the second embodiment.
In the grommet, the inclination direction of the seal lip 15 is directed to the side surface 12 on the inclined wall side of the enlarged diameter cylindrical portion 3. Therefore, the deep bottom portion 16 provided on the bottom surface 10 of the annular recess 6 is provided between the root 15b of the seal lip 15 and the side surface 12, and the bottom surface 10 on the side surface 11 side on the large diameter side is set as the reference height S (reference depth). Yes. Further, the built-up portion 18 provided on the inner peripheral surface of the enlarged diameter cylindrical portion 3 at the bottom of the annular recess 6 is provided and reinforced on the surface facing the entire bottom surface 10.
Since other configurations are the same as those of the first embodiment, the same reference numerals are given and description thereof is omitted.

  As described above, even if the inclination direction of the seal lip 15 is reversed, the required seal pressure can be ensured only by changing the amount of inclination of the seal lip 15 in the inclination direction according to the shape of the burring 112.

7A and 7B show a grommet according to the third embodiment.
The grommet is provided on the bottom surface 10 of the annular recess 6 with a seal lip having a large protruding dimension inclined to the side surface 11 as in the first embodiment as a first seal lip 15A, and on the non-inclined side of the first seal lip 15A. A second seal lip 25 is provided adjacently. The boundary position of the base ends of the first and second seal lips 15A and 25 is the center point of the bottom surface 10 in the width direction.

  The second seal lip 25 has a projecting dimension smaller than that of the first seal lip 15 </ b> A and projects in the direction perpendicular to the bottom surface 10. The height h4 of the second seal lip 25 is 1.5 mm to 2.0 mm, which is about 0.5 mm lower than the first seal lip 15A.

Since the first seal lip 15A and the second seal lip 25 are arranged side by side on the bottom surface 10 of the annular recess 6, the first seal lip 15A is closer to the side surface 11 than in the first embodiment. Therefore, the deep bottom portion 16 provided on the bottom surface on the first seal lip 15A side is connected to the side surface depression 26 provided on the side surface 11 so that the first seal lip 15A that has fallen down can be accommodated from the deep bottom portion 16 into the side surface depression 26. Yes.
In addition, a built-up portion 18 is provided and reinforced on the surface facing the deep bottom portion 16 in the same manner as in the first embodiment.

In the grommet of the third embodiment, as shown in FIG. 7 (B), the burring 112 can be pressed against the first and second seal lips 15A, 25, and the water stop performance can be improved. In particular, the burring 112 is likely to vary from the bent side to the tip side due to the bending R from the vehicle body 110. Therefore, since the first seal lip 15A that is easy to fall is disposed at a position where it comes into contact with the front end side of the burring where the variation is large, the first seal lip 15A can be reliably brought into contact with the burring. And since the 2nd seal lip 25 is arrange | positioned at the bending point side with a comparatively small dimension dispersion | variation, this 2nd seal lip 25 can also be made to contact the burring 112. FIG.
In addition, although two seal lips are provided in the annular recess 6, the first seal lip 15 </ b> A having a large protrusion amount is easy to fall, whereas the second seal lip 25 which is not easily collapsed has a small protrusion amount. When the burring 112 is inserted and locked in the annular recess, a large resistance is not generated, and deformation of the grommet can be prevented.

8A and 8B show a grommet according to the fourth embodiment.
As in the third embodiment, the grommet projects the first seal lip 15A and the second seal lip 25 from the bottom surface of the annular recess 6, and the first seal lip 15A is disposed on the side surface in the same manner as in the second embodiment. Since the second seal lip 25 is inclined toward the 12 side, the second seal lip 25 protrudes adjacent to the side surface 11 side with respect to the first seal lip 15A.
Other configurations and operational effects are the same as those of the second and third embodiments, and thus the same reference numerals are given and the description thereof is omitted.

DESCRIPTION OF SYMBOLS 1 Grommet 3 Diameter expansion cylinder part 6 Ring-shaped recessed part for vehicle body latching 10 Bottom face 11, 12 Side face 15 Seal lip 15A 1st seal lip 15h 1st small protrusion 15i 2nd small protrusion 16 Deep bottom part 18 Overlay part 25 2nd seal Lip 110 Car body 111 Through hole 112 Burring

Claims (3)

A grommet formed from rubber or elastomer that is fitted and fixed to a wire harness and is attached to a through-hole with a burring formed in a vehicle body,
An annular recess for locking the vehicle body fitted to the inner periphery of the through hole with a burring is provided on the outer peripheral surface of the cylindrical portion surrounding the wire harness through hole, and a seal lip is provided on one side of the bottom of the annular recess. The bottom surface of the annular concave portion on the inclined side of the seal lip is formed as a deep bottom portion that is dug from the root of the seal lip and deeper than the other bottom surface on the non-inclined side; Grommet characterized by making the lip easy to collapse.   The grommet according to claim 1, wherein the inner peripheral surface of the bottom wall facing the bottom surface is thickened by a size corresponding to the amount of the bottom surface on the inclined direction side of the seal lip.   A second seal lip protrudes from the bottom surface of the seal lip on the bottom surface of the annular recess, and the second seal lip has a protruding height lower than that of the inclined seal lip and is not inclined. The grommet according to claim 1, wherein the grommet protrudes perpendicularly to the bottom surface.

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