JPH03281238A - Double-layer tube and use thereof - Google Patents

Abstract

PURPOSE:To obtain a double-layer tube enhanced in the bonding strength of the inner and outer layers thereof by constituting said tube of a the inner layer composed of fluoroplastic and having a polygonal outer peripheral shape in its cross section and the outer layer made of a thermoplastic resin laminated to the outer peripheral surface of the inner layer. CONSTITUTION:The outer peripheral shape of the cross section of a low frictional tubular inner layer 1 composed of fluoroplastic is set to hexagonal shape and the inner peripheral shape thereof is made circular. The tubular outer layer 2 made of a thermoplastic resin (excepting fluoroplastic) laminated to the outer peripheral surface of the inner layer 1 is pref. formed from a thermoplastic elastomer such as polybutylene terephthalate, polyacetal, polyamide, polyurethan or polyester from the aspect of mechanical strength and heat resistance. The outer peripheral shape of the cross section of the inner layer is set to the hexagonal shape but can be set to an arbitrary polygonal shape such as a triangular shape, a square shape, an octagonal shape, a decagonal shape or a dodecagonal shape without being limited to the hexagonal shape. By making the outer peripheral cross section of the inner layer polygonal, the bonding strength with the outer layer can be increased and the shift of the inner and outer layers can be prevented.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a conduit cable used for remote transmission of operating force such as throttle operation of an automobile.
The present invention relates to a low-friction multilayer tube that can be applied to BLE, etc.

(Prior art) (1) Conduit cables (also called control cables) used for automobile throttle operation have a basic structure of a wire inserted loosely into a low-friction tube, and the wire can be remotely controlled. slide inside the tube.

A fluororesin type tube is preferred as the low-friction tube, but since this tube is expensive, its wall thickness is generally set as thin as possible.

On the other hand, in order to use this tube as a conduit cable, it is common to loosely insert a wire inside the tube and caulk the end with a metal ring.

However, in a conduit cable in which a wire is loosely inserted into a fluororesin tube, the inner diameter of the tube is reduced and deformed during caulking because the tube is thin, which may impede the sliding properties of the wire.

In order to prevent shrinkage and deformation of the inner diameter of such thin-walled duplexes, it was proposed in 1973 to provide a sulfur-retaining layer with excellent hardness on the outer periphery (2) of the thin-walled fluororesin tube.
This is proposed in Japanese Patent No. 7-93613.

The two-layer tube according to the above proposal has a structure in which a protective layer, which is harder than the fluororesin, is provided on the outer peripheral surface of a thin tube made of a fluororesin and has a circular cross-sectional outer circumference.

In order to use this double-layer tube as a conduit cable, for example, as shown in FIG. A cable structure in which a thermoplastic resin layer 5 is provided so as to be wound and to fill the reinforcing wire 4,
A terminal fitting 8 is attached to the end portion, and a metal ring 9 is fitted onto the terminal fitting 8 and caulked. It is preferable to use a double-layered tube such as a steel ring because the stress during caulking by the metal ring is absorbed by the protection N7, thereby preventing shrinkage and deformation of the inner diameter of the thin-walled tube.

(Problem to be Solved by the Invention) However, in this two-layer tube, the inner layer is made of fluororesin and the cross-sectional outer circumference of the inner core layer is circular. The adhesive strength is weak. Therefore, when a wire is loosely inserted into the inner layer and used as a conduit cable, the adhesive force between the inner layer and the outer layer cannot resist the sliding force of the wire, and the thin duplex as the inner layer moves as the wire slides. (a phenomenon of misalignment between the inner layer and the outer layer) may occur. This movement phenomenon causes an increase in sliding resistance, resulting in poor operability and premature wear of the gou-yube.

Therefore, an object of the present invention is to provide a multilayer tube having a strong adhesive strength between the fluororesin dupe as an inner layer and an outer layer, and a conduit cable using the tube.

(Means for Solving the Problems) As a result of intensive studies in view of the above-mentioned current situation, the inventors of the present invention have discovered that the intended purpose can be achieved by making the cross section of the outer circumferential surface of a fluororesin tube into a specific shape. The invention was completed.

That is, the multilayer tube (4) according to the first aspect of the present invention includes an inner layer made of fluororesin and having a polygonal outer circumference in cross section, and an outer layer made of thermoplastic resin laminated on the outer circumferential surface of the inner layer. It is characterized by a core consisting of.

Further, the conduit kale according to the second aspect of the present invention includes an inner layer made of fluorine resin and having a polygonal cross-sectional outer periphery;
The present invention is characterized in that a wire is loosely inserted into the inner layer of a multilayer tube consisting of an outer layer made of thermoplastic resin laminated on the outer peripheral surface of the inner layer.

Hereinafter, the present invention will be described in detail with reference to the drawings. In Figure 1, ■ is polytetrafluoroethylene (PT).
FE), tetrafluoroethylene hexafluoropropylene copolymer (FEP), tetrafluoroethylene-
Perfluoroalkyl vinyl ether copolymer (PFA
), ethylenetetrafluoroethylene copolymer (ETF
E), polychlorotrifluoroethylene (PCTFE)
, polyvinylidene fluoride (PVdF), and ethylene-chlorotrifluoroethylene copolymer (EC(5) TFE). The outer peripheral shape of the cross section of this tubular inner layer 1 is hexagonal, and the inner peripheral shape is circular. Note that this inner layer may be formed into a tube shape by blending various additives with a fluororesin. For example, to improve wear resistance, inorganic additives such as carbon fiber, glass fiber, graphite, molybdenum disulfide, etc., and organic additives such as aromatic polyester, polyphenylene sulfide, etc. can be blended.

2 is a tubular outer layer made of thermoplastic resin (excluding fluororesin) laminated on the outer peripheral surface of inner layer 1, and is made of polybutylene terephthalate, polyacecool, polyamide from the viewpoint of mechanical strength, heat resistance, etc. It is preferable to use thermoplastic elastomer such as polyurethane or polyester. In this example, the outer layer is a single layer, but a multilayer structure of two or more layers can be used if desired.

Such a multilayer tube of the present invention can be produced by, for example, a method of melting and extruding a thermoplastic resin onto the outer peripheral surface of a fluororesin tube, such that the fluororesin is the inner layer and the thermoplastic resin is the outer layer. It can be manufactured by a method of simultaneously extruding each into a tube shape.

In the example described above, the shape of the cross-sectional outer circumference of the inner layer is hexagonal, but the present invention is not limited to this, and the cross-sectional outer circumference of the inner layer may have any shape such as a triangle, quadrilateral, large angle, keigon, ten triangular, etc. Can be set to a polygon. By making the cross-sectional outer periphery of the inner layer polygonal in this way, the adhesive force with the outer layer is increased as shown in the examples described later, and it is possible to prevent the inner layer and the outer layer from being scratched.

FIG. 2 shows an example in which the multilayer cable shown in FIG. 1 is used as a connecting cable. A wire 3 having an outer diameter slightly smaller than the inner diameter of the inner layer 1 is loosely inserted into the inner layer 1 of the multilayer tube, and a reinforcing wire 4 made of steel wire or the like is placed on the outer layer 2.
is wound around the reinforcing wire 4, and the polyamide
Thermoplastic resin layer 5 such as polyvinyl chloride, Volip D pyrene, etc.
has been formed.

(7) To caulk the end of a conduit cable, attach a terminal to the end of the cable, for example, as described in the above-mentioned Japanese Utility Model Publication No. 57-93613, and insert the terminal directly above the end. All you have to do is fit a metal ring to the hole and caulk it.

(Effects of the Invention) The present invention is constructed as described above, and since the cross-sectional outer periphery of the inner layer of the multilayer duplex is polygonal, it is possible to increase the adhesive force with the outer thermoplastic resin layer laminated thereon. Even if the wire slides in the inner layer, the inner layer and the outer layer are firmly integrated, so there is an advantage that no increase in sliding resistance occurs.

(Example) Example I A paste is prepared by uniformly mixing 82 parts by weight of fine powder of PTFE and 18 parts by weight of naphtha, and this paste is applied to a mold (the diameter of the circumscribed circle of the die hole is 4 mm). The naphtha was processed into a hexagonal shape with a diameter of 3 mm and the diameter of the core pin placed at the center of the die hole was 3 mm. Heat for 10 minutes with
TFE is fired to obtain P''FFE.

This tube has a hexagonal cross-sectional outer circumference, an inner diameter of 2.9 mm, and a circumscribed circle diameter of 3.8 mm.

Next, a multilayer duplex with the same structure as shown in Fig. 1 was obtained by extrusion coating polyacecool on the outer peripheral surface of this P T F E tube at a temperature of 200°C to a thickness of 5 mm. Ta.

Example 2 PTFEi powder 100 parts by weight, length 6 pieces, diameter 0.01
Prepare a paste made by uniformly mixing 18 parts by weight of 5 mm carbon fiber and 16 parts by weight of naphtha, and place this paste into a mold (the diameter of the circumscribed circle of the die hole is /l mm).
The naphtha was extruded into a tube shape from a core pin with a diameter of 4 mm placed at the center of the die hole, and then the naphtha was evaporated and heated to a temperature of 37 (9) O'. PTFE is baked by heating at C for 10 minutes, and the PTFE
Get a tube.

This tube has a 10-triangular cross-sectional outer circumference, an inner diameter of 3.95 mm, and a circumscribed circle diameter of 4.9 mm.

Next, polyamide was coated on the outer peripheral surface of this tube at a temperature of 30°C.
A multilayer tube was obtained by extrusion coating at 0°C to a thickness of 0.5 mm.

Comparative Example 1 The work was carried out in the same manner as in Example 1, except that a mold was used in which the die hole had a circular shape, the diameter was 4 cylinders, and the core pin diameter placed at the center of the die hole was set to 3 mm. A multilayer tube was obtained.

The structure of this multilayer tube is the same as shown in FIG. 4, with an inner diameter of 2. A PTFE tube of 9 mm in diameter and 3.8 mm in outer diameter (the cross-sectional shape of the outer circumference is circular) has a thickness of 0.0 mm.
An outer layer of 5 mm polysecure is provided.

Comparative Example 2 (■0) Same as Example 2 except that a mold was used in which the die hole was circular, the diameter was 5 mm, and the core pin diameter placed at the center of the gouge hole was 4 mm. work on,
A multilayer tube was inserted.

The structure of this multilayer tube is also the same as that shown in Fig. 4, and it is placed on the outer circumferential surface of a PTFE tube with an inner diameter of 3.7 mm and an outer diameter of 4°55 mm (its cross-sectional outer circumference is circular) with a thickness of 0.5 mm.
An outer layer of 5 mm polyamide I. is provided.

Multilayer dip 4 obtained by these Examples and Comparative Examples
-B was subjected to characteristic tests in the following manner, and the obtained results are shown in Table 1.

A. Pull-out strength At one end of a multi-layer tube cut to a length of 100 mm, peel off the outer layer to expose the inner layer, grasp this exposed inner layer, and fix the outer layer at the other end.
The force (kg) at which the inner layer and outer layer shift is measured by pulling at a speed of 1/min.

Figure 3 shows the multilayer tube cut to B8 interlayer deviation length L 00 mm.
11) As shown in the figure, the radius of curvature is 75 mm at the center.
The entire tube is curved to form a U-shape, and the deviation distance I between the inner layer 1 and outer layer 2 at the end of the multilayer tube at this time is
, (mm).

Table 1

[Brief explanation of the drawing]

1 and 2 are front views showing actual examples of the multilayer tube and conduit cable according to the present invention, FIG. 3 is a schematic diagram showing a method for measuring the characteristics of the multilayer tube according to the present invention, and FIG. 4 is a sectional view showing a conventional product. 1... Inner layer 2... Outer layer 3... Wire (12)

Claims (2)

[Claims] (1) A multilayer tube comprising an inner layer made of fluororesin and having a polygonal outer circumference in cross section, and an outer layer made of thermoplastic resin laminated on the outer circumferential surface of the inner layer. (2) A wire is loosely inserted into the inner layer of a multilayer tube consisting of an inner layer made of fluororesin and having a polygonal cross-sectional circumference, and an outer layer made of thermoplastic resin laminated on the outer circumferential surface of the inner layer. A conduit cable featuring: