JPH0434206A - Liner of control cable - Google Patents

Abstract

PURPOSE:To improve heat resistance, strength, and hardness by forming the flexible liner of a control cable with fluoric resin capable of being subjected to fusion extrusion molding, and biaxially extending it in both longitudinal and laterial directions. CONSTITUTION:A liner 10 is made of fluoric resin consisting of copolymer of tetrafluoroethylene and parfluoroalkylvinylether, and given flexibility, while an inner cable 20 having flexibility obtained by standing metal element wires, and is inserted therein. A conduit 30 may be formed around the liner 10. As the liner 10 can be subjected to fusion extrusion molding, no baking is required rather having, superior heat resistance, and superior strength for bending and the like, because of biaxial extension in both longitudinal and lateral and breadth both directions while friction damage according to slide movement of the inner cable 20 in the inner surface of the liner 10 hardly takes place due to improved hardness, and sliding operation can be made smooth by reducing friction resistance with the inner cable 20.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention is mainly used to remotely control transmissions, brakes, clutches, etc. (hereinafter referred to as transmissions, etc.) of automobiles, motorcycles, bicycles, etc. (hereinafter referred to as automobiles, etc.). Concerning improvements to liners used in control cables.

(Prior art) Liners for control cables traditionally used for remote control of automobile transmissions, etc. ■The inner surface of the liner is smooth to allow smooth sliding operation of the inner cable. ■It has good wear resistance because it wears out on the contact surface when it slides with the inner cable. - Flexible enough to withstand excessive bending and strong enough to prevent cracking. ■In particular, cables for automobiles have excellent heat resistance because they are wired close to the engine.

is considered to be the main requirement.

Therefore, the liner of the control cable has conventionally been made of polyethylene, polypropylene, polyester, etc.
Thermoplastic resins such as polyamide (hereinafter referred to as polyethylene, etc.) have been used, but none of them satisfy all of the conditions (1) to (2) above.

Therefore, the following (a) or (b) was proposed.

(a) Use base extrusion molding of polytetrafluoroethylene (PTFE).

(b) Use biaxially stretched polyethylene or the like as described above.

(Problem to be solved by the invention) However, in the above conventional (a), heat resistance,
Although it has an excellent effect on chemical resistance, the following (a) to (
There was a drawback of c).

(a) It is necessary to bake the paste after extrusion molding, which leads to high costs, and since continuous molding is not possible, the length is limited.

(b) A liner made only of PTFE has poor wear resistance under high loads.

(c) In order to improve the above (b), PTFE mixed with graphite etc. may cause cracks to occur between the graphite and PTFE in tube molded products, for example.
Durability is poor, and the inner cable has poor sliding properties due to unevenness on the inner surface of the tube due to the cracks.

Moreover, in the above (+), although orientation cracking is suppressed because biaxial stretching is employed, there is a drawback that heat resistance is insufficient.

Therefore, the present invention was devised, and its objectives are to provide heat resistance against high temperatures such as those found in automobile engines, excellent strength against bending, etc., hardness that prevents wear and damage caused by sliding of the inner cable, and An object of the present invention is to provide a liner for a control cable that is flexible and extrudable.

(Means for Solving the Problems) The configuration of the present invention for achieving the above object will be described below based on drawings corresponding to embodiments.

That is, the flexible liner (10) of the control cable (100) into which the inner cable (20) is slidably inserted is made of a fluororesin that can be melted and extruded, and is biaxial in both vertical and horizontal directions. The control cable liner (10) is characterized in that it is stretched.

(Function) With the above means, the control cable liner (10) according to the present invention has flexibility and can be freely routed. Since it can be melt-extruded, there is no need for baking in the manufacturing process. Furthermore, since it is made of fluororesin, it has excellent heat resistance and does not melt even at high temperatures.

Furthermore, since it is biaxially stretched in both the vertical and horizontal directions, it has excellent strength against bending, etc., and the hardness is improved by this biaxial stretching, so that the inner cable (20) can easily slide on the inner surface of the liner (10). This suppresses the occurrence of unevenness on the inner surface of the liner (10) by reducing wear and damage caused by the liner (10), and reduces the frictional resistance between the inner cable (20) and the inner cable (20), thereby smoothing the sliding operation of the inner cable (20). .

(Example) The following detailed description of the present invention with respect to Figures 1 to 3 shows typical examples that are considered to be good, and the present invention is not limited to this example. do not have.

That is, the liner (10) of the control cable according to this embodiment is made of a fluororesin made of a copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether (PFA), and has flexibility. A flexible inner cable (20) made of twisted metal wires is inserted through the liner (10). Further, around the liner (10), a conduit (3
0) may be formed.

In the above-mentioned liner (10), the above-mentioned PFA is used as the fluororesin, but in addition to that, a copolymer of tetrafluoroethylene and hexafluoropropylene (FE) is used.
P) etc. may be used.

The liner (10) was biaxially stretched 5.4 times in the vertical direction and 1.9 times in the horizontal direction, but other magnifications may be used. However, when stretched more than 8 times, the hardness becomes too high due to the stretching effect and the inner cable (
The same inner cable (20) that occurs when operating 20)
It is desirable that the stretching ratio is 8 times or less in both the longitudinal and lateral directions, since collision noise between the liner (lO) and the engine vibration and chatter noise are likely to occur.

Example 1.2 regarding the liner (10) according to the present invention as described above (both 5.4 times in the vertical direction and 1.9 times in the horizontal direction)
The hardness of Comparative Example 3°4 (both biaxially stretched) and Comparative Example 3°4 (both unstretched) was measured, and the results shown in Table 1 below were obtained.

PFA was used for the liner (10) according to Example 1 and Comparative Example 3, and FEP was used for the liner (IO) according to Example 2 and Comparative Example 4.

In addition, the measuring device shown in FIG. 4 (Model DMH-2 manufactured by Matsuzawa Seiki Co., Ltd.) was used for the above measurement.

Further, the numerical values in Table 1 above represent the hardness (H3), and are the average value of the measurement results of 10 samples each.

Table 1 From the results in Table 1 above, it can be confirmed that the hardness increases by biaxial stretching.

Next, the loading efficiency of Examples 1 and 2 and Conventional Example 3 was measured under conditions where the ambient temperature was room temperature and 130° C., and Tables 2 and 3 below were obtained. PBT was used for the liner according to Conventional Example 3.

Moreover, this loading efficiency was determined by the following method.

As shown in Figures 5 and 6, the inner cable (20
) is inserted into the liner (10) with a radius (R) of 125
Wrap it around the outer circumference of a mm disc for one and a half turns (450'') and fix it, and attach a weight (W) to the negative end of this inner cable (2o).Then, the inner cable (20)
The other end is set at a speed of 30 strokes/min and a stroke length of 70 m.
Pull it in the direction of the arrow with m to make it slide back and forth. Using the tensile force (F) at this time and the weight (W), the loading efficiency is determined by the following formula.

Atmosphere week now I [Σku warm ψ　　　　　　　　　.

Loading efficiency (%) = -X100 W; weight (25 kg) F; tensile force (kg value read from load cell) From Tables 2 and 3 above, the liner (10 kg) according to Examples 1 and 2
) has high loading efficiency under both ambient temperature conditions of room temperature and 130°C. This is because the liners (10) according to Examples 1 and 2 are both fluororesins with excellent heat resistance (PFA has a melting point of 310°C,
Since the melting point of EP is 275°C), there is almost no change in the shape of the liner (10) due to heat at room temperature or 130°C, and because it is biaxially stretched, the liner (10) has a High hardness, inner cable (20)
This is because the inner surface of the liner (10) is less likely to be worn and damaged and become uneven due to the sliding of the liner (10), so that the sliding operation of the inner cable can be performed smoothly.

In comparison, the liner in Conventional Example 3 had a significantly lower loading efficiency, especially under the condition of an ambient temperature of 130°C, and as shown in Table 3, the tensile force (F) was It was too large to be measured, and the loading efficiency could not be determined. This is PBT
(melting point is 225°C), and at 130°C, the shape of the liner itself changes due to softening due to heat.
As a result, the inner surface of the liner tends to become uneven, and since it has been softened by heat, the inner surface of the liner is likely to wear out due to the sliding of the inner cable, and this abrasion causes the inner surface of the liner to become uneven and cause friction on the inner surface of the liner. This is thought to be due to the fact that the resistance increases and therefore the sliding operation of the inner cable cannot be performed smoothly.

Furthermore, when bending tests were conducted on the liners (10) of the control cables according to Examples 1 and 2 on 10 samples each, no orientation cracks were found in any of them.

(Effects of the Invention) As explained above, according to the present invention, the following effects (1) to (4) are achieved.

In other words, the liner of the control cable according to the present invention is: (1) Biaxially stretched in both the vertical and horizontal directions, which improves strength and reduces orientation cracking.

■Biaxial stretching in both vertical and horizontal directions increases hardness, so
Wear and damage to the inner surface of the liner due to sliding operation of the inner cable is reduced. Therefore, the unevenness on the inner surface of the liner caused by wear and tear is reduced, resulting in smaller frictional resistance.
Therefore, the sliding operation of the inner cable can be performed smoothly.

■Since it is made of fluororesin, it has excellent heat resistance, so it can be used with confidence, especially in places where high temperature bodies exist, such as the engine room of a car.

■Since extrusion molding is possible, the manufacturing process is simple and can be provided at a low cost.

[Brief explanation of drawings]

Fig. 1 is a perspective view of a control cable equipped with a liner according to an embodiment of the present invention, Fig. 2 is a front view of the same, Fig. 3 is a sectional view taken along line A-A, and Fig. 4 is used in this embodiment. FIG. 5 is a front view of the device for measuring tensile force (F), and FIG. 6 is an enlarged sectional view taken along the line B-B of the same device. Explanation of the symbols 10... Liner of the control cable according to the embodiment of the present invention, 20... Inner cable, 30...
Conduit, 100...control cable. that's all

Claims (1)

[Scope of Claims] A flexible liner for a control cable into which an inner cable is slidably inserted, which is made of a fluororesin that can be melt-extruded and biaxially stretched in both the vertical and horizontal directions. A control cable liner featuring: