JPH021529Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) This invention is a cable that is routed near a heat generating element such as an engine or a muffler in a cable for transmitting rotation to a vehicle speedometer, tachograph, etc. Regarding heat-resistant structures constructed in

(Prior art) Conventionally, heat resistance has been imparted to this type of cable by heating the cable, which causes melting or deterioration of the cable's exterior resin, deterioration of the lubricant sealed in the cable, and the sheathing and exterior coating. Thermal expansion of the steel wires and other parts that are braided into the cable may cause sudden bends in areas where the outer resin has softened locally, resulting in damage to the cable, shortened service life, or damage to the cable inserted into the outer sheath. This is done as a means to prevent interference with the rotation of the rotary shaft.

The conventional heat-resistant structure applied to cables for this purpose is to use EPDM (ethylene propylene diene monomer) on the outer periphery of cable a, as shown in Figure 3.
The structure is such that an interference material b formed of a sponge-like foam is covered with a material such as, and a heat-resistant tube c made of a material such as glass cloth is further wrapped around the outer periphery of the interference material b.

(Problem to be solved by the invention) However, in the heat-resistant structure of such a cable, since the interference material b is a sponge-like foam, the air contained inside suppresses the heat conduction from the heat-resistant tube c to some extent. At the same time, although it has the effect of preventing the cable a from shifting in the heat-resistant tube c, the air layer contained in the sponge-like foam is not necessarily sufficient, and the solid layer of the interference material b in contact with the heat-resistant tube c is Since the contact surface is large, heating of the cable a cannot be sufficiently prevented by heat conduction, and there is a problem that it is difficult to fully demonstrate the performance of the heat-resistant tube c.

The present invention was made in view of the above-mentioned problems of the conventional interference material b, and aims to provide a heat-resistant structure for a cable in which heat transfer from the heat-resistant tube to the cable is extremely small.

(Means for Solving the Problems) The present invention will be described in detail below based on the accompanying drawings showing embodiments.

FIG. 1 is a partially cutaway perspective view showing the heat-resistant structure of the cable of the present invention, and FIG. 2 is a sectional view taken along the line AA in FIG. 1.

In the figure, the heat-resistant structure of the cable of the present invention covers the outer periphery of the cable 1 with a tube 2 in which a plurality of convex strips 2a with a chevron-shaped cross section extending in the axial direction are provided at approximately equal intervals in the circumferential direction. The tube 2 is equipped with a heat-resistant tube 3.

In the above configuration, the tube 2 is made of synthetic rubber with good heat resistance such as styrene-butadiene rubber (SBR), nitrile rubber, chloroprene rubber, butyl rubber, isobutylene rubber, etc. A plurality of strips are provided at approximately equal intervals through the holes 2b, and are formed by extrusion molding so that the cross section in the direction perpendicular to the axis is approximately star-shaped. Therefore, its outer diameter is set to approximately match the inner diameter of the heat-resistant tube 3. Note that the heat-resistant tube 3 used is the same as the conventional one.

(Function) According to the heat resistant structure of the cable of the present invention, as shown in FIG. The area becomes extremely small, and most of the contact surface becomes an air layer with extremely low thermal conductivity in the grooves 2b. The heat transfer from the heat-resistant tube 3 heated by the heating element (not shown) to the cable 1 is therefore significantly reduced. Also, chevron-shaped protrusions 2
The fins a act as heat radiation fins and have the effect of dissipating the heat transmitted to the tube 2 to the air layer of the groove 2b, thereby further reducing heat transfer to the cable 1.

In addition, the tube 2 can also prevent the cable 1 from shifting inside the heat-resistant tube 3 by forming chevron-shaped protrusions 2a on the outer circumferential surface of the tube 2 at approximately equal intervals to function in exactly the same way as conventional interference materials. Can be done.

Further, the material of the tube 2 is not limited to a rubber tube, but may be a resin material such as nylon resin, noryl resin, or polycarbonate resin as long as it has heat resistance and flexibility.

Since the heat-resistant structure of the cable of the present invention has the above-mentioned effects, it can be widely applied not only to rotation transmission cables but also as a heat-resistant structure for ordinary power cables.

(Effects of the invention) As described above, the present invention provides a tube 2 on the outer periphery of the cable 1, in which a plurality of convex strips 2a extending in the axial direction and having a chevron-shaped cross section are provided at approximately equal intervals in the circumferential direction. Since the tube 2 is coated with the heat-resistant tube 3, the heat-resistant tube and the protrusions having a chevron-shaped cross section are in almost line contact, and most of the contact surface with the heat-resistant tube is between the protrusions. Because it forms an air layer, it is possible to significantly reduce heat transfer from the heat-resistant tube to the cable compared to the case where a conventional sponge-like foam is used as an interference material, further improving the durability of the cable. Moreover, since the tube used in the present invention can be easily produced by extrusion molding, advantages such as helping to reduce costs can be obtained.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway perspective view of the present invention, FIG. 2 is a sectional view taken along line AA in FIG. 1, and FIG. 3 is a partially cutaway perspective view of a conventional cable heat-resistant structure. 1... Cable, 2... Tube, 2a... Chevron-shaped convex strip, 2b... Concave strip, 3... Heat-resistant tube.

Claims (1)

[Scope of utility model registration request] The outer periphery of the cable 1 is coated with a tube 2 in which a plurality of convex strips 2a having a chevron-shaped cross section extending in the axial direction are provided at approximately equal intervals in the circumferential direction on the outer periphery, and the tube 2 is covered with a heat-resistant tube 3. The heat-resistant structure of the cable is characterized by: