JPS6324444B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a cable conduit used for remote control of various industrial machines and equipment and devices used in various other fields, particularly a cable conduit provided with a curved portion.

Conventionally, a cable conduit consists of a conductor made of wire or stranded cable that transmits power, a conduit through which the conductor is inserted to guide and protect it, and a conduit attached to the end of the conduit to protect the conduit end. It also consists of a fitting that functions as a fixed end to fix the conduit in a predetermined position.
The conductor and conduit, excluding the fitting, are flexible.

The advantage of power transmission using this cable conduit is that by bending the conduit section, the operating direction can be changed in almost any way, but the problem is that the curvature of this conduit section There is a limit to the degree of bending, and bending with an extremely small radius of curvature must be avoided, and bending similar to bending is virtually impossible.

This depends on the reasons for its construction, such as whether the conduit consists only of a synthetic resin tube, or whether it is reinforced by winding steel wire or steel strips around the synthetic resin tube, but generally speaking If the cable is bent in the manner described above, the cable guide hole will be deformed as if it were crushed, reducing transmission efficiency and accelerating wear in that area, significantly shortening the service life of the cable conduit, and even causing breakage of the cable. There is a risk of accidents.

Therefore, the curvature of the conduit portion is made to have as large a curvature as possible to avoid unnatural curvature, but depending on the purpose of use or the location of attachment, the curvature of the conduit portion may cause problems.

For example, it is necessary to arrange the cable conduit along a flat surface such as a flat panel or side wall, and the actuated part is on the opposite side of the flat surface, and the actuated part is perpendicular to the flat surface. In the case where a hole is drilled in the plane part and power is transmitted to the actuated part through the hole, the conduit part of the cable conduit should be bent once away from the plane part well before the hole. ,
The fitting must then engage the hole at right angles.

There is no problem if you can take the space necessary to curve the cable conduit like this, but if there is no space, or the curved part becomes an obstacle to attaching it to other parts, or Furthermore, if there are problems such as deterioration of aesthetic appearance, some kind of solution is desired.

If it is forced to curve with a small curvature, it will cause the damage mentioned above.

In order to solve these problems, the present applicant previously filed Utility Application No. 55-62448 (Utility Model Application No. 163810) and Japanese Patent Application No.
No. 55-94309 (Japanese Unexamined Patent Publication No. 57-20326), Patent Application No. 56-
In No. 82778 (Japanese Unexamined Patent Publication No. 57-200717), we proposed a cable conduit equipped with a synthetic resin fitting having a curved cable guide hole and a method for manufacturing the same.

Here, the technology of Japanese Patent Application No. 55-94309 is shown in the drawings as follows.

In the figure, 1 is a conduit, and the conduit 1 includes a synthetic resin tube 3 having a cable guide hole 2 on its inner surface, and a plurality of reinforcing steel wires 4 wound around the outer circumference of the tube 3 with appropriate leads. It consists of a synthetic resin casing 5 which covers the outer periphery of the tube 3 and a steel wire 4.

6 is a folded end formed on the reinforcing steel wire 4; 7
is the exposed end of the synthetic resin tube 3.

8 is a liner member, and the liner member 8 is provided with a curved inner hole (guiding hole) 9 and an enlarged diameter portion 10 at one end. Reference numeral 11 encloses the folded end 6 of the reinforcing steel wire 4, covers the end of the synthetic resin casing 5, and covers the liner member 8 temporarily fixed by fitting to the exposed end 7 of the synthetic resin tube. This is a synthetic resin fitting made by integrally molding the

In this way, in the prior art, the direction change of the strength, especially at the end of the conduit, is fixed to a liner member having a curved guide hole, without causing strain on the conduit part, which is difficult to curve due to its small curvature. It has the advantage that it can be carried out effectively by providing a synthetic resin fitting.

However, the production thereof requires complicated steps, such as forming a folded end of the reinforcing steel wire at the end of the conduit and forming a synthetic resin liner member having a curved guide hole.

In addition, apart from the above-mentioned prior art, when a single thermoplastic synthetic resin tube is used as a conduit, the curved portion can be formed by, for example, a post-forming method; Forming it without any problem not only involves processing that is considerably difficult, but also requires the separate formation of fittings for attachment to other members.

The present invention relates to an improvement on the above-mentioned prior art, and in particular, its technical object is to provide a method for manufacturing a cable conduit having a curved portion, which simplifies the manufacturing method.

The configuration of the present invention, that is, the technical means to achieve the above technical problem, is as follows.

Curving a conduit having a guide hole on the inner surface with a predetermined curvature at a predetermined position to form a curved part in the conduit, and holding the curved part against the spring back of the curved part. a process of placing the curved part in the mold in a state in which the curved part is bent and positioning the curved part in the cavity of the mold, and integrally molding a synthetic resin having rigidity to cover the curved part in the cavity of the mold. A method of manufacturing a cable conduit comprising a step of depositing and forming a synthetic resin fitting, the curved part of the conduit being held and fixed by the synthetic resin fitting, and having a curved part that suppresses spring back of the curved part of the conduit. .

Here, a conduit is a single thermoplastic synthetic resin tube that has a guiding hole on its inner surface and functions to smoothly slide and guide a guiding cable made of wire or stranded cable inserted through the guiding hole. , a structure consisting of a thermoplastic synthetic resin tube, a plurality of reinforcing steel wires wound around the outer periphery of the tube with appropriate leads, and a synthetic resin casing covering the outer periphery of the reinforcing steel wire and the tube. The structure includes a thermoplastic synthetic resin tube, a reinforcing steel strip wound around the outer periphery of the tube, and a synthetic resin casing covering the outer periphery of the reinforcing steel strip.

When the above-mentioned conduit is bent at an arbitrary position and with an arbitrary curvature, the curved section of the conduit tends to return to its original straight shape due to spring back.

This springback appears even more strongly in conduits containing reinforcing steel wires or reinforcing steel strips.

Resisting this spring back, a rigid synthetic resin is integrally molded to cover the curved portion of the conduit, and a synthetic resin fitting is applied thereto, and the fitting suppresses the spring back of the curved portion of the conduit, and the curved portion is It is the subject of this configuration, that is, of the technical means, to hold and fix the.

The thermoplastic synthetic resin tube of the conduit and the thermoplastic synthetic resin tube of the above-mentioned conduit are in direct contact with the guiding rope to smoothly slide and guide the guiding rope. Resin is prized.

Polyamide resins, polyacetal resins, thermoplastic polyester resins, or high-density polyethylene resins are preferred, and solid lubricants such as graphite, molybdenum disulfide, or ethylene tetrafluoride resin powders, mineral oils, synthetic lubricating oils, and waxy substances. It is even more preferable to use a blend of the following to improve friction and wear performance.

The synthetic resin used for fitting is particularly strong and rigid, such as polyamide resin blended with a reinforcing base material such as glass fiber powder, ABS resin, thermoplastic polyester resin, etc. as preferred examples. Can be done.

This synthetic resin fitting is integrally formed to cover the curved portion of the conduit, and consists of a curved portion having a predetermined curvature and degree of curvature, and a straight portion continuous to the curved portion.

By taking the above-mentioned technical means, the manufacturing complexity in the prior art described above can be removed, and a cable conduit with a curved portion can be manufactured very easily.

In addition, since the conduit does not have a seam or a stepped portion seen in the prior art at the curved portion, the guiding cable can be more smoothly slidably guided.

For the purpose of the present invention, it is desirable that the radius of curvature of the curved portion formed in the conduit is as small as possible, but this depends on the thickness (diameter) of the conductor rope used and the thickness of the conduit. Ru.

In addition to these reasons for the shape and structure, the radius of curvature of the curved portion of the conduit generally becomes smaller, and as the degree of curvature increases, the transmission efficiency decreases even if there is no deformation such as crushing in the guide hole of the conduit. Since this may lead to deterioration and also have a large effect on the life of the conduit, it is necessary to make a decision after comprehensive consideration, taking into consideration the purpose of use.

According to the present invention, a conductor with a diameter of 1.5 mm and an outer diameter of 6
mm, in the case of a combination with a conduit with an inner diameter of 3 mm, there will be no deformation in the conductor hole at any position of the conduit up to a maximum angle of 60 degrees (angle between the straight part and the curved part of the conduit) with respect to the conduit axis. It is possible to form the structure without causing such problems.

Examples will be described below with reference to the drawings.

FIG. 2 is a cross-sectional view showing the manufacturing method, and FIG. 3 is a cross-sectional view showing a cable conduit with a curved portion obtained by the manufacturing method.

In the figure, A is the mold, B is the synthetic resin injection port,
C is a cavity formed in the mold A in the shape of a fitting.

Reference numeral 20 denotes a conduit, and the conduit 20 includes a thermoplastic synthetic resin tube 30 having a cable guide hole 31 on its inner surface, a plurality of reinforcing steel wires 40 wound around the outer circumference of the tube 30 with appropriate leads, and It is composed of a reinforcing steel wire 40 and a synthetic resin casing 50 covering the outer periphery of the tube 30.

60 is a curved portion formed in the conduit 20 with a predetermined curvature.

The conduit 20 is inserted into the mold A with its curved portion 60 held against the spring back of the curved portion.
The curved portion 60 is positioned within the cavity C of the mold A.

Then, molten synthetic resin is injected into the cavity C from the synthetic resin injection port B of the mold A, and the curved portion 60
A synthetic resin fitting 70 is integrally formed to cover it.

This synthetic resin fitting 70 has a curved portion 71.
and linear portions 72 and 73 connected to the curved portion 71. The synthetic resin fitting 70 suppresses the springback of the conduit curved portion 60 and holds and fixes the curved portion 60 to the conduit 20.

Conduit with an inner diameter of 3 mm and an outer diameter of 6 mm (including reinforcing steel wire)
In this case, holding and fixing a curved section having a predetermined curvature on the conduit against the spring back of the curved section was achieved by forming a synthetic resin fitting with a wall thickness of 3 mm.

In addition, when using a single thermoplastic synthetic resin tube for the conduit, even if the melting point of the synthetic resin used for synthetic resin fitting is higher than that of the synthetic resin of the tube, the molten state injected into the cavity Since the resin is cooled and solidified fairly quickly, the cable guide hole of the tube will not be deformed.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the prior art, FIG. 2 is a sectional view showing the manufacturing method of the present invention, and FIG. 3 is a sectional view showing a cable conduit obtained by the manufacturing method shown in FIG. A: Mold, C: Cavity, 20: Conduit, 6
0: Curved portion, 70: Synthetic resin fitting.

Claims (1)

[Claims] 1. (1) Curving a conduit having a guide hole on the inner surface with a predetermined curvature at a predetermined position to form a curved portion in the conduit; (2) Curving the curved portion. (3) placing the curved part in the mold while holding it against the spring back of the curved part, and positioning the curved part in the cavity of the mold; a step of integrally molding a synthetic resin having rigidity to cover the curved portion, and forming a synthetic resin fitting to hold and fix the curved portion of the conduit, and a spring of the curved portion of the conduit; A method for manufacturing a cable conduit having a curved portion characterized by suppressed back. 2. The method for manufacturing a cable conduit with a curved portion according to claim 1, wherein the conduit is made of a thermoplastic synthetic resin tube. 3. The conduit consists of a thermoplastic synthetic resin tube, a plurality of reinforcing steel wires wound around the outer periphery of the tube with appropriate leads, and a synthetic resin casing covering the reinforcing steel wires and the outer periphery of the tube. A method for manufacturing a cable conduit having a curved portion according to claim 1. 4. The conduit comprises a thermoplastic synthetic resin tube, a reinforcing steel strip wound around the outer periphery of the tube, and a synthetic resin casing covering the outer periphery of the reinforcing steel strip. A method for manufacturing a cable conduit having a curved portion.