JP2015019527A - Protective material for wiring harness, and protective structure for wiring harness - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a corrugate tube-like protective material with proper workability for passing a wiring harness with a connector in a lengthwise direction.SOLUTION: A protective material for a wiring harness is made of bellows tube-like heat-shrinkable tubing in which annular mountain and valley parts are alternately provided in an axial direction. An inside diameter before heat shrinkage caused by heating is large enough to enable insertion of the wire harness with a connector. The protective material is heated and shrunk after the insertion of the wiring harness with the connector.

Description

  The present invention relates to a protective material for a wire harness and a protective structure for the wire harness, and particularly to a protective material that protects a wire harness that is routed in a region to which oil of an automobile adheres in a bendable manner.

  Conventionally, an adhesive tape, a resin tube, and a corrugated tube have been widely used as a protective material for a wire harness in which a group of electric wires routed in an automobile is converged. The adhesive tape is spirally wound around the electric wire group for bundling protection, and when preventing penetration of water or oil, half-wrapping is performed to ensure that the electric wire group is not exposed to the outside. When the half wrap winding is performed, there is a problem that the rigidity of the wire harness becomes high and it is difficult to bend. The resin tube is also difficult to bend, and it is necessary to pass the wire group from one end to the other end of the resin tube in the length direction. This wire passing work takes time, and a connector is connected to the end of the wire group. If there is, there is a problem that the connector cannot be passed.

The corrugated tube is excellent in flexibility, and the corrugated tube with a slit having one continuous slit in the axial direction can open the slit and insert the electric wire group from the lateral direction perpendicular to the length direction. The corrugated tube can be attached after connecting the connector to the end of the electric wire group, and the attachment workability is good. However, it is necessary to prevent the opening of the slit by winding an adhesive tape so that the electric wire does not protrude from the slit after passing through the electric wire group. When the wire harness is routed in the transmission of an automobile and always immersed in fluid oil, the adhesive tape wound around the outer periphery of the corrugated tube with slits is eroded by the oil and the durability is lost, so the adhesive tape cannot be used. .
When a corrugated tube without slits is used, it is not necessary to wrap the adhesive tape, but it is necessary to pass the wire group from one end in the length direction of the corrugated tube, and usually a connector is connected to the tip of the wire group. A large-diameter corrugated tube that allows the connector to be inserted is required. If the corrugated tube becomes larger in diameter, the group of wires passing through the corrugated tube tends to become loose, and a large space is required for the wiring harness, making it impossible to route in a narrow wiring space. .

  Conventionally, Japanese Patent Application Laid-Open No. 2002-354629 provides a tube 100 for protecting electric wires shown in FIG. The tube is made of a two-color molded product of resin and rubber, and is provided with elastic portions 102 continuous in the length direction at a plurality of locations in the circumferential direction of the resin-made cylinder 101 so as to be inflatable. In the tube 100, since the connector C at the end of the electric wire enters the cylindrical body 101 from the state shown in FIG. 5 (A), the elastic body 102 deforms the cylindrical body 101 from an elliptical shape to a rectangular shape. Thus, the connector C can be inserted.

JP 2002-354629 A

  In the tube 100 of Patent Document 1, the cross-sectional area does not change greatly only by being deformed by the elastic portion 102 so that the connector C can be inserted. Therefore, the diameter of the tube is determined by the size of the connector C, the inner diameter of the tube is considerably larger than the wire harness diameter, and there is a problem that the diameter cannot be maximized as a protective material for the wire harness. In addition, since the two-color molding is performed with the resin and the rubber, there is a problem that if the elastic portion is pulled strongly at the time of expansion, peeling easily occurs at the boundary with the resin portion.

  The present invention has been made in view of the above problems, and the diameter of the resin is increased to such an extent that the connector of the electric wire terminal can be easily inserted while forming a resin corrugated tube shape without using a two-color molded product of resin and rubber. Another object of the present invention is to provide a protective material for a wire harness that can be reduced to the maximum diameter after passing through the wire.

  In order to solve the above-mentioned problems, the present invention comprises a bellows tubular heat-shrinkable tube in which annular crests and troughs are alternately provided in the axial direction, and the inner diameter before heat-shrinking by heating is inserted through the wire harness with connector. Provided is a protective material for a wire harness that is of an acceptable size and that is heat-shrinked after insertion of the wire harness with connector.

  As described above, the protective material for the wire harness of the present invention is a bellows tubular heat-shrinkable tube, in other words, a corrugated tube having no slit formed by a heat-shrinkable tube material, and has an inner diameter before heat shrinkage. Since the large connector can be inserted, the wire harness with the connector can be easily passed from one end to the other end in the length direction. Moreover, since the corrugated tube is reduced in diameter after being heated and shrunk after the wire harness is passed, there is an advantage that a large wiring space is not required. In addition, since the bellows shape is maintained even after the heat shrinkage, it has flexibility and no tape winding work is required because there is no slit.

Moreover, this invention provides the protection structure of the wire harness protected by the said protective material and the inner peripheral surface of the said trough part closely_contact | adhered to the outer peripheral surface of a wire harness at the time of heat contraction.
As described above, when the bellows tubular heat-shrinkable tube is heated and shrunk and contracted until the inner peripheral surface of the valley portion of the tube is substantially in close contact with the outer peripheral surface of the wire harness, oil intrusion can be reduced at the close contact portion. .

Provided is a wire harness protection structure in which a wire harness that is immersed in oil in an automobile transmission is sheathed with the protective material.
Since the protective material of the present invention consists of a corrugated tube without slits, tape winding for preventing the electric wires from protruding from the slits is not required, and therefore there is no problem of tape erosion due to oil, and the protective material is durable.

  As described above, the protective material for a wire harness according to the present invention is formed of a heat-shrinkable tube material with a slit-free corrugated tube. Can be inserted. Further, after the threading operation, the maximum diameter can be easily achieved by heat shrinking.

Embodiment of the protective material of this invention is shown, (A) is a front view, (B) is a perspective view before heat shrinkage, (C) is a perspective view after heat shrinkage. It is drawing which shows the manufacturing process of the said protective material. (A) is a perspective view which shows the state at the time of the attachment operation | work of the protection material to a wire harness, (B) is a perspective view after attachment. It is a top view which shows the wiring location of the wire harness protected with the said protective material. (A) (B) is a perspective view which shows a prior art example.

Hereinafter, an embodiment of a protective material for a wire harness of the present invention will be described with reference to the drawings.
1A to 1C show a bellows tubular heat-shrinkable tube 1 as a protective material of the present invention. As shown in FIG. 1 (A), annular valleys 2 and peaks 3 are alternately provided in the length direction, and there are no slits continuous in the length direction, and the shape is similar to that of a corrugated tube without slits. . FIG. 1B shows a state before heat shrinkage, and FIG. 1C shows a state after heat shrinkage. The inner diameter after thermal contraction of (C) is reduced by 40% or more (in this embodiment, about 50%) from the inner diameter of (A).

The bellows tubular heat-shrinkable tube 1 is made of polyethylene as a main material in the same manner as the heat-shrinkable tube that is widely used, and is molded by the process shown in FIG. That is,
A resin composition mainly composed of polyethylene similar to that of a conventional heat-shrinkable tube is introduced into the hopper 10, and after kneading in the hopper 10, the resin composition is introduced into the extruder 11, and the cylindrical tube 30 is introduced into the first molding machine 12. Extrude. While the compressed air is inserted into the tube by the first molding machine 12, it is extruded and conveyed into the pair of left and right molds 12A and 12B of the first molding machine 12, and is brought into close contact with the mold surfaces of the concave and convex molds 12A and 12B. Then, the bellows tube 31 is formed. While the bellows tube 31 is extruded from the first molding machine 12 and conveyed to the second molding machine 14, the electron beam irradiator 13 irradiates the bellows tube 31 with an electron beam to cause a cross-linking reaction to the bellows tube 31. To give shape memory. After the electron beam irradiation, the bellows tube 32 is expanded in diameter by being plasticized while passing through an oil bath heated again by the second molding machine 14. This expanded state is the state before heat shrinkage shown in FIG. 1 (B), and is continuously manufactured and wound up. The bellows tube 31 in a state of being molded by the first molding device 12 and memorized by electron beam irradiation is in a state after the heat shrinkage shown in FIG.

  As described above, the bellows tubular heat-shrinkable tube 1 formed from the resin composition has a hollow cross-sectional area in which the inner diameter before contraction in FIG. 3A is larger than the outer shape of the connector 21 of the wire harness 20 with the connector to be inserted. I have it. Further, the length of the bellows tubular heat-shrinkable tube 1 is shortened by about 15% during heat-shrinking. Therefore, in consideration of this contraction rate, the length of the bellows tubular heat-shrinkable tube 1 is 115% with respect to the total length of the wire group 24 connecting the connectors 21 and 22, and the wire group is extended to the base of the connectors 21 and 22 after heat shrinkage. It can be protected over almost the entire length.

The operation of attaching the bellows tubular heat-shrinkable tube 1 to the wire harness 20 with a connector is as follows. One end opening 5 in the length direction of the bellows tubular heat-shrinkable tube 1 is connected to the connector 21 in the state before the heat-shrinkage shown in FIG. Insert it. The connector 21 is pulled out from the other end opening 6, the wire group 24 is passed through the bellows tubular heat-shrinkable tube 1, and the wire harness passing operation is completed in a state where the other end connector 22 is close to the one end opening 5.
Next, the bellows tubular heat-shrinkable tube 1 is heated at a required heating temperature and contracted as shown in FIG. In this contracted state, the inner diameter of the valley portion 3 of the bellows tubular heat-shrinkable tube 1 is reduced to the same extent as the outer diameter of the wire group 24, and the valley portion 3 of the bellows tubular heat-shrinkable tube 1 is formed on the outer peripheral surface of the wire group 24. The inner peripheral surface of the oil can be substantially adhered, and the intrusion of oil from the outside can be reduced at the position of the valley.

  As shown in FIG. 4, a wire harness 20 (indicated by a thick line in the figure) sheathed with the bellows tubular heat-shrinkable tube 1 is routed in the transmission M of the automobile. Although the wire harness 20 is bent and routed as shown in the drawing, since the wire harness 20 is the bellows tubular heat-shrinkable tube 1, it can be bent easily. In addition, although the wire harness 20 is always immersed in the fluid oil in the transmission M, since the adhesive tape is not wound around the bellows tubular heat-shrinkable tube 1, there is no problem that the adhesive tape is eroded by the oil. .

  The present invention is not limited to the above-described embodiment, and can also be suitably used as an exterior material for a wire harness that is routed to other parts of the vehicle.

1 Bellows tubular heat-shrinkable tube (protective material)
2 Mountain part 3 Valley part 20 Wire harness with connector 21, 22 Connector 24 Electric wire group

Claims (3)

  It consists of a bellows tubular heat-shrinkable tube with annular crests and troughs arranged alternately in the axial direction, and the inner diameter before heat shrinkage by heating is large enough to allow insertion of a wire harness with connector. A protective material for a wire harness that is heated and shrunk after the wire harness is inserted.   A protective structure for a wire harness that is protected by the protective material according to claim 1 and in which an inner peripheral surface of the valley portion is in close contact with an outer peripheral surface of the wire harness during heat shrinkage.   The protection structure of the wire harness which coat | covers the wire harness immersed in oil within the transmission of a motor vehicle with the protective material of Claim 1.

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