JPS6410686B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cable conduit for load transmission, and more specifically, the present invention relates to a cable conduit for load transmission, and more specifically, a cable conduit having excellent load transmission efficiency and durability, whose sliding surface is made of a specific fluorine-containing copolymer. This invention relates to a load transmission cable conduit.

BACKGROUND ART Conventionally, load transmission cable conduits such as automobile accelerator wires have been widely used for remote control of various transportation-related equipment and the like. The load transmission cable conduit is
An inner cable such as a copper wire or a wire made of several copper wires twisted together is used as an inner cable, the inner cable is slidably inserted into a protective conduit, and one end of the inner cable is pushed or pulled or rotated to open the other end. It transmits the load to the connected passive equipment and operates it.

Such a load transmission cable conduit is often long or bent during installation, and the friction between the inner cable and the inner surface of the conduit is extremely large. Therefore, there is a strong tendency for load transmission efficiency to be inhibited due to frictional resistance and for wear and tear to occur due to repeated use. Conventionally, lubricating oil such as silicone oil or grease was injected between the inner cable and the conduit, or polyacetal resin, nylon resin, polytetrafluoroethylene (PTFE),
An inner tube made of tetrafluoroethylene-hexafluoropropylene copolymer (FEP) has been proposed, but it has insufficient load transfer efficiency, insufficient heat resistance, and durability. However, some difficulties are recognized. Furthermore, in Japanese Unexamined Patent Application Publication No. 136549/1984, molybdenum disulfide, graphite, etc. are fixed to the sliding surface to improve heat resistance and sliding friction resistance, but there is a risk of poor durability due to wear damage. Difficulties are not resolved.

Based on the recognition of the above-mentioned problems, the present inventor has conducted various studies and examinations, and as a result, the ethylene-
At least a fluorine-containing copolymer selected from the group consisting of a tetrafluoroethylene copolymer (hereinafter abbreviated as ETFE) and an ethylene-trifluorochloroethylene copolymer (hereinafter abbreviated as ECTFE) It has been discovered that a material to which a carbon substance is added has excellent advantages as a sliding surface material for a load transmission cable conduit. In other words, it not only has the same effect of improving load transfer efficiency and heat resistance as ETFE, ECTFE, FEP, graphite, etc. that are mixed with carbon materials, but also has the advantage of being able to withstand repeated use over a long period of time. has. In addition, the sliding surface may be formed by coating the surface of the inner cable, inserting a tube, etc., and significant advantages are also recognized in terms of melt adhesion during coating, ease of tube molding, etc.

Thus, the present invention has been completed based on the above findings, and provides a load transmission cable conduit in which a load transmission cable is slidably inserted into a protective conduit. A new cable conduit for load transmission characterized in that the sliding surface of the cable is composed of at least one fluorine-containing copolymer selected from the group consisting of ETFE and ECTFE mixed with a carbon substance. This is what we provide.

According to the present invention, firstly, the slipperiness of the inner rope cable is improved, which makes it easier to operate the pedal in, for example, an automobile accelerator wire. In addition, load transmission efficiency is improved compared to conventional silicone oil. Furthermore, since it has good creep resistance,
It has good durability and can be used many times more than conventional PTFE, FEP, etc. It also has superior heat resistance and slipperiness compared to polyacetal resin and nylon resin. Thus,
According to the present invention, it is possible to provide a load transmission cable conduit with excellent durability and good load transmission efficiency even under severe conditions.

The specific fluorine-containing copolymer used in the present invention can be produced by a catalytic emulsion polymerization method in an aqueous medium, a suspension polymerization method, or an organic solvent such as a fluorinated chlorinated saturated hydrocarbon or tertiary butanol. Those produced by various polymerization methods such as catalytic polymerization, gas phase polymerization, and ionizing radiation irradiation polymerization, or those whose content ratios of ethylene and tetrafluoroethylene or trifluorochloroethylene are changed in various ways. In addition to ethylene and tetrafluoroethylene or trifluorochloroethylene, small amounts of monomers (propylene, isopropylene, vinyl fluoride, vinylidene fluoride, hexafluoropropylene, perfluoroalkylethylene, acrylic Acids and their alkyl esters, perfluorovinyl ethers, etc.) and modifiers.

Therefore, as ETFE or ECTFE in the present invention, tetrafluoride is selected from the viewpoint of sliding properties, creep resistance, heat melting properties, easy availability, intended use in cable conduits, various excellent physical properties, etc. The molar ratio of ethylene (or trifluorochloroethylene)/ethylene is about 40/60 to 70/30, especially about 45/55 to 60/40, and the volume flow rate defined below is 10 to 300 mm ³ /
seconds, particularly about 25 to 160 mm ³ /second.
If the molar ratio and volumetric flow rate are outside the above range, the sliding properties, creep resistance, heat-melting properties, heat resistance, chemical resistance, etc. may deteriorate, or the properties as a specific fluorine-containing copolymer may deteriorate. It is.

The term "volume flow rate" as used herein is defined as follows. In other words, using a Koka type flow tester, test the temperature at the specified temperature and the specified load at 30°C.
Kg/cm ² , 1 g of sample is extruded through a nozzle with a nozzle diameter of 1 mm and a land of 2 mm, and the value expressed as the volume of the molten sample extruded per unit time is defined as the "volume flow rate", and the unit is is mm ³ /sec. Here, the predetermined temperature is a temperature within the temperature range (temperature range between the flow start temperature and thermal decomposition start temperature) in which the specific fluorine-containing copolymer can be molded and close to the flow start temperature. Ru. Then,
For the specific fluorine-containing copolymer of the present invention,
260-360℃ for ETFE, 220℃ for ECTFE
A predetermined temperature is selected in the range of ~340°C, and temperatures above the thermal decomposition start temperature are not adopted.

Furthermore, the carbon material used in the present invention is
There may be a wide range of forms including powder, particulate, fibrous, fiber powder, etc. Therefore, the addition/mixing ratio of the carbon material in the present invention is approximately 0.1 to 10% by weight, particularly 0.2% by weight, considering sliding properties, creep resistance, heat melting properties, intended use of the cable conduit, etc. ~5
Approximately % by weight is desirable. Usually the length is less than 500μ,
In particular, carbon fiber powder pulverized to 200μ or less is preferably employed.

Furthermore, in the present invention, a solid lubricant such as molybdenum disulfide may be added and mixed.

In the present invention, the sliding surface is formed by coating the inner cable with a fluorine-containing copolymer containing a carbon substance, and by coating the inner surface of the conduit with a fluorine-containing copolymer containing a carbon substance. There is a method of inserting a tube of a fluorine-containing copolymer mixed with a carbon material into the gap between the inner cable and the conduit. Therefore, in the case of coating, the coating thickness is about 30 to 1000 microns, preferably about 50 to 500 microns,
In addition, in the case of tube insertion, the tube wall thickness is approximately 100 to 1000 microns, preferably 200 to 500 microns.
A size on the order of microns may be adopted.

As methods for forming sliding surfaces in various forms as described above, electrostatic powder coating method, dispersion coating method, fluidized dipping coating method, and other appropriate coating methods are employed. Similarly, the inner cable can be coated by extrusion molding. Alternatively, a tube of a fluorine-containing copolymer to which a carbon substance is added and mixed can be formed into a tube by a melt extrusion method or the like, and the tube can be used. Of course, it is possible to form the tube in a similar manner, and the tube need not be fixed to both the inner cable and the conduit.

ETFE suitable for the present invention has a flow start temperature of 260-300°C, especially 270-290°C, and a thermal decomposition start temperature of 340-360°C, especially 345-355°C. Suitable ECTFE also has a flow start temperature of 220 to 260.
℃, thermal decomposition onset temperature is 300-340℃. Therefore, the baking temperature or melt forming temperature of the coating is:
The temperature range between the flow start temperature and thermal decomposition start temperature is selected, and in the case of ETFE, it is about 260 to 360 °C, especially 270 to 340 °C, and in the case of ECTFE, it is about 220 to 340 °C.
A temperature of about 330°C, especially 240 to 300°C, is adopted. still,
The time required for baking is not particularly limited as long as a coating film is formed, and the optimum range will depend on the formation of the sliding surface, the temperature used, the thickness of the coating film, the physical properties of the specific copolymer, etc. Generally, a period of about 5 to 30 minutes is appropriate.

In the present invention, there is no particular reason to limit the inner cable or the protective conduit, and a wide range of conventionally known or well-known ones may be employed. For example, the inner cable may be not only a wire made of several stranded metal wires, but also a single metal wire, and the conduit may be a tube made of one or more metal wires spirally wound, or An example is a pipe with two or more layers of helical winding. In addition, a lubricant such as grease is usually injected between the inner cable and the protection pipe. Also,
It is also possible to seal both ends of the conduit with flexible rubber protective tubes to prevent dirt from entering the conduit.

The novel load transmission cable conduit of the present invention as described above has excellent load transmission efficiency and durability, and also has good heat resistance, so that it can be applied to a wide range of uses by taking advantage of such characteristics. For example, the accelerator, brake, opening/closing of the bonnet of a car, opening/closing of a heater heat valve, the accelerator of a motor boat, the direction lever, the water valve operation of an electric washing machine, the door wire of an electric oven, etc. may be exemplified.

Next, embodiments of the present invention will be described in more detail, but it goes without saying that the present invention is not limited by such explanations.

In addition, in the following examples, tests for load transmission efficiency and durability were conducted as follows. That is, the test apparatus shown schematically in FIG. 1 of the accompanying drawings was used. In Figure 1, 1 is a heat insulating box, 2 is a protective conduit, and 3
indicates an inner rope cable, 4 indicates a 4.2 kg weight, 5 indicates a motor that provides a reciprocating motion of 50 cycles/min with a stroke of 25 mm, and 6 indicates a fixed pulley with a radius of 80 mm. Durability is determined by repeating reciprocating motion and observing changes in transmission efficiency and the condition of the sliding surface. In addition, the load transmission efficiency can be calculated using the formula W ₀ /W ₁ ×100 by setting the load W ₀ of the weight 4, removing the motor 5, attaching a load meter, and measuring the load W ₁ required for tension. Calculate with.

Example 1 The molar ratio of tetrafluoroethylene/ethylene is 53/
47, flow start temperature 265℃, thermal decomposition start temperature
Adding 5% by weight of carbon fiber powder (fibers with a diameter of 10μ to a length of 100μ or less) was added to an ethylene-tetrafluoroethylene copolymer at a volumetric flow rate of 90mm ³ /sec at 345°C and 300°C, By melt extrusion method, inner diameter
A tube with a diameter of 4.2 mm and a wall thickness of 200 μm was molded. Connect this tube to a wire (diameter: 2 mm in diameter and 1 m in length).
20 strands of 0.37mm steel wire) with an inner diameter of 5mm and an outer diameter of 7mm
After inserting the wire between the protective conduit (a flexible conduit made by winding a metal coil) and filling it with silicone oil, a load of 4.2 kg was applied to one end of the wire, and the wire was reciprocated at a stroke of 25 mm and a speed of 50 cycles/min. When the load transfer efficiency was measured during exercise, it was 80%, and this value did not change even after 2 million repeated tests. When a tube made of tetrafluoroethylene-hexafluoropropylene copolymer was used instead of the tube described above, the load transfer efficiency was 85%, but the load transfer efficiency was 120%.
The tube broke after 10,000 repeated tests.

Example 2 As a fluorine-containing copolymer, the molar ratio of ethylene trifluoride/ethylene was 50/50, and the flow start temperature was
Ethylene-trifluorochloride ethylene copolymer was used at 239°C, thermal decomposition initiation temperature was 316°C, and volume flow rate was 100 mm ³ /s at 260°C, and the amount of carbon fiber powder added was 2.
The same test as in Example 1 was conducted except that the weight % was used. As a result, the load transfer efficiency was 82%, and this value remained unchanged even after 2 million repeated tests.

Example 3 A test similar to Example 1 was conducted except that the amount of carbon fiber powder added to the fluorine-containing copolymer was 1% by weight, and the outer surface of the wire was coated with a thickness of 200 μm. As a result, the load transfer efficiency was 85%, and this value did not change even after 2 million repeated tests. The load transfer efficiency when not coated with the fluorine-containing copolymer was 75%.

[Brief explanation of drawings]

The attached Figure 1 schematically shows the test equipment for load transmission efficiency and durability, in which 1 is a heat insulation box, 2 is a protective conduit, 3 is an inner cable, 4 is a weight, and 5 is a fixed pulley. shown respectively.

Claims (1)

[Scope of Claims] 1. A load transmission cable conduit in which a load transmission cable is slidably inserted into a protective conduit, in which the sliding surfaces of the cable and the conduit are made of ethylene-tetrafluoroethylene. A load transmission device comprising at least one fluorine-containing copolymer selected from the group consisting of a polymer and an ethylene-trifluorochloroethylene copolymer, in which a carbon substance is added and mixed. Cable conduit. 2 Ethylene-tetrafluoride as a fluorine-containing copolymer having a molar ratio of tetrafluoroethylene/ethylene of 40/60 to 70/30 and a volume flow rate of 10 to 300 mm ³ /sec as defined in the text. The load transmission cable conduit according to claim 1, which uses an ethylene copolymer. 3 Ethylene-trifluoroethylene as a fluorine-containing copolymer having a trifluorochloroethylene/ethylene molar ratio of 40/60 to 70/30 and a volume flow rate of 10 to 300 mm ³ /sec as defined in the text. The load transmission cable conduit according to claim 1, which uses an ethylene-based copolymer. 4. The load transmission cable conduit according to claim 1, wherein the carbon material is added in a mixing ratio of 0.1 to 10% by weight. 5. The load transmission cable conduit according to claim 1, wherein the carbon material is carbon fiber powder.