JP2003004170A - Grommet for cable penetration - Google Patents

Abstract

(57) [Abstract] (with correction) [Problem] To reduce the number of parts of a waterproof structure of a cable penetration part and simplify a construction method. A grommet (32) integrally formed of rubber is used. The grommet 32 has a cylindrical portion 34, an annular protrusion 36, an annular protrusion 38, and an annular protrusion 40.
The inner diameter of the cylindrical portion 34 is larger than the outer diameter of the cable 10 and the outer diameter is a hole.
The size is close to the inner surface of 22a. The annular projection 36 can pass through the hole 22a when the outer diameter is larger than the inner diameter of the hole 36 and is elastically deformed in the diameter reducing direction. The umbrella-shaped brim portion 38 extends in a trumpet shape toward the opposite end. When the cable is inserted into the annular ridge 40, the inner diameter of which is smaller than the outer diameter of the cable 10, the annular ridge 40 is expanded by the cable and comes into close contact with the outer peripheral surface of the cable. When the annular projection 36 is pushed into the hole 22a until it projects to the back side of the wall 22, the umbrella-shaped flange 38 is elastically deformed and pressed against the wall around the hole, and the annular projection 36 and the umbrella-shaped collar 38 Surrounding wall
22 is sandwiched.

Description

Description: BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a grommet for a cable penetrating portion used to maintain watertightness of a portion where a cable is introduced into a connection box or the like. 2. Description of the Related Art Heretofore, a portion where an optical cable is introduced into a connection box has been subjected to waterproof treatment as shown in FIG. 3 or FIG. In the waterproofing method shown in FIG. 3, first, as shown in FIG. 3 (A), a first sealing material 12A is wound around an optical cable 10, and a donut-shaped end face plate 14 having a circumferential portion is provided at one place in the circumferential direction. Installing. Next, as shown in FIG.
The second sealing material 12B is inserted into a portion of 14 and the protruding portion (hatched portion) is cut out. Next on the outer circumference (C)
Then, the third sealing material 12C is wound and the release tape 16 is peeled off as shown in FIG. Next, a stainless steel wire 18 is wound around the outer periphery as shown in FIG. Reference numeral 18a denotes a portion where both ends of the stainless steel wire 18 are twisted. Finally, as shown in (E), the outer periphery of the third sealing material 12C is sandwiched between the end face walls of the split connection box 20 to provide a waterproof structure. With this structure, a water pressure resistance of 98 kPa or more can be obtained. In the waterproof structure shown in FIG. 4, a metal tube 24 is inserted into a hole of a wall 22 of a connection box and welded in advance, and the optical cable 10 is made to penetrate the metal tube 24. A seal material 12, a vulcanized rubber tape (for example, a GS tape) 26, a stainless steel wire 18, an adhesive aluminum tape 28, and a polyvinyl chloride tape 30 are sequentially wound around the outer periphery of the tape 10. [0005] The conventional waterproof structure of the cable penetrating portion has a large number of parts, requires a complicated construction method, and requires much labor. In addition, since a technique is required for winding the sealing material or the tape, there is a concern that the waterproof performance may differ depending on the operator. An object of the present invention is to provide a grommet for a cable penetrating portion that solves the above problems. A grommet for a cable penetrating portion according to the present invention is entirely formed integrally from a material having rubber elasticity, and has an inner diameter larger than an outer diameter of the cable and an outer diameter of the cable. It has a cylindrical portion of a size that is in close contact with the inner surface of the hole in the penetrating wall, and passes through the hole when the outer diameter is larger than the inner diameter of the hole and elastically deformed in the diameter-reducing direction on the outer periphery of one end of the cylindrical portion. Having a possible annular projection, on the outer periphery of the other end of the cylindrical portion, having an umbrella-shaped brim portion that spreads in a trumpet shape toward one end, on the inner periphery of the other end of the cylindrical portion, The inner diameter is smaller than the outer diameter of the cable.When the cable is inserted, the cable has an annular ridge which is pushed out and spreads closely to the outer peripheral surface of the cable, and is pushed into the hole until the annular protrusion projects to the back side of the wall. Umbrella-shaped collar deforms elastically around hole I pressed against the wall, and is characterized in that is adapted to pinching the wall around the hole in the annular projection and the umbrella-shaped flange portion. Hereinafter, embodiments of the present invention will be described.
This will be described in detail with reference to the drawings. FIG. 1 shows an embodiment of the present invention. The grommet 32 for the cable penetrating part is entirely formed integrally with elastic rubber. Reference numeral 34 denotes a cylindrical portion whose inner diameter is larger than the outer diameter of the cable 10 and whose outer diameter is in close contact with the inner surface of the hole 22a of the wall 22. It is preferable that the outer diameter of the cylindrical portion 34 be set slightly larger than the inner diameter of the hole 22a. On the outer periphery of one end side (inner end side) of the cylindrical portion 34, there is formed an annular projection portion 36 having an outer diameter larger than the inner diameter of the hole 22a and capable of passing through the hole 22a when elastically deformed in the diameter reducing direction. I have. An umbrella-shaped brim portion 38 is formed on the outer periphery of the other end side (outer end side) of the cylindrical portion 34 so as to expand in a trumpet shape toward the one end side. Further, on the inner circumference on the other end side of the cylindrical portion 34, an annular raised portion 40 is formed, which has an inner diameter smaller than the outer diameter of the cable 10 and is pushed and spread by the cable when the cable 10 is inserted, and is in close contact with the outer peripheral surface of the cable. As shown in FIG. 2, when the grommet 32 is pushed into the hole 22 a until the annular projection 36 projects to the back side of the wall 22, the umbrella-shaped collar 38 is elastically deformed and the wall around the hole 22 a is deformed. And the annular projection 36 and the umbrella-shaped brim 38
With this, the wall 22 around the hole 22a is sandwiched. As a result, the umbrella-shaped brim portion 38 comes into close contact with the outer surface of the wall 22, and the cylindrical portion
Since the outer peripheral surface of 34 is in close contact with the inner surface of hole 22a, waterproofness between wall 22 and grommet 32 is ensured. Also grommet 32
When the optical cable 10 is inserted into the optical cable 10, the annular ridge 40 is expanded and comes into close contact with the outer peripheral surface of the optical cable 10, so that waterproofness and airtightness between the grommet 32 and the optical cable 10 are also ensured. As an example of the dimensions of the grommet 32, when the outer diameter of the optical cable 10 is 5 mm, the thickness of the wall 22 is 7 mm, and the inner diameter of the hole 22a is 10 mm, the inner diameter of the cylindrical portion 34 is 6.5 mm, and the outer diameter is 10.5m
m, the outer diameter of the annular projection 36 is 12 mm, and the outer diameter of the umbrella-shaped collar 38 is 2
Preferably, the inner diameter of the annular ridge 40 is 3.5 mm, and the total length is 14 mm. With this dimension, a water pressure resistance of 98 kPa or more can be obtained. A grommet of this size can correspond to an optical cable having an outer diameter of 4 to 6 mm. As described above, if the grommet according to the present invention is used, the waterproofness of the cable penetrating portion can be ensured by one component, the construction method is extremely simple, and the There is a remarkable effect that there is no possibility that the waterproof performance varies.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view showing an embodiment of a grommet for a cable penetration portion according to the present invention. FIG. 2 is a sectional view showing a use state of the grommet of FIG. 1; FIGS. 3A to 3E are explanatory views showing an example of a conventional waterproof structure of a cable penetration portion in the order of steps. FIG. 4 is a cross-sectional view showing another example of the conventional waterproof structure of the cable penetration portion. [Description of Signs] 10: Optical cable 22: Connection box wall 22a: Hole 32: Grommet 34: Cylindrical portion 36: Annular protrusion 38: Umbrella-shaped brim 40: Annular ridge

Claims (1)

Claims: 1. A size which is integrally formed of a material having rubber elasticity and whose inner diameter is larger than the outer diameter of a cable and whose outer diameter is in close contact with the inner surface of a hole in a wall through which the cable passes. The cylindrical portion (34) has an outer periphery on one end side of the cylindrical portion (34).
An outer diameter is larger than the inner diameter of the hole, and has an annular projection (36) that can pass through the hole when elastically deformed in the diameter reducing direction. An umbrella-shaped brim portion (38) spreading in a trumpet shape toward the cylinder portion (3)
4) has an annular ridge (40) in the inner periphery on the other end side, which has an inner diameter smaller than the outer diameter of the cable and is pushed and spread by the cable when the cable is inserted into the cable so as to be in close contact with the outer peripheral surface of the cable; When the projection (36) is pushed into the hole until it protrudes to the back side of the wall, the umbrella-shaped collar (38) is elastically deformed and pressed against the wall around the hole, and the annular projection (36) and the umbrella-shaped collar ( A grommet for cable penetrations, characterized in that the wall around the hole is sandwiched in 38).