JPS6045573B2 - Method for manufacturing cable conduits - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cable conduit used for remote control of various industrial machines and other equipment and devices used in various fields.

Conventionally, a cable conduit consists of a conductor made of wire or stranded cable that transmits power, a casing that guides and protects the inserted conductor, and is attached to the end of the casing to protect the casing end. It also includes a cap that also functions as a fixed end for fixing the cable conduit to the operating and actuated side members, and the cable and casing, excluding the cap, are flexible. The advantage of power transmission using a cable conduit is that by curving the casing part almost any change in the direction of operation can be effected without the use of articulations. However, there is a limit to the degree of curvature of this casing part, and bending with an extremely small radius of curvature must be avoided, and bending similar to bending is practically impossible. This depends on the reasons for the structure of the casing, such as whether the casing is made only of synthetic resin tubes or whether the synthetic resin tube is reinforced with steel wire or steel strips, but generally speaking If the cable is bent as described above, the cable guide hole will be deformed as if it were crushed, which will not only reduce the power transmission efficiency, but also accelerate the wear of the cable at the curved part, which will significantly shorten the service life of the cable conduit. This is to reduce the risk of damage, and in some cases there is a danger that this could lead to accidents such as wire breakage.

Therefore, this casing part is curved with a large curvature as natural as possible to avoid unnatural curvature, but depending on the purpose of use or the location where it is installed, it may be inconvenient to curve the casing part. may occur. For example, it is necessary to arrange a cable conduit along J on a flat surface such as a flat panel or side wall, and the actuated part is on the opposite side of the side wall, and the actuated part is against the flat surface such as the side wall. In the case where a hole is bored in the side wall of the part and power is transmitted to the actuated part through the hole,
The casing portion of the cable conduit must be bent away from the side wall surface well before the hole, so that the cap portion of the cable conduit can be engaged at right angles to the hole.

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 other parts, or it spoils the aesthetics. If you have any problems such as
Some kind of solution is desired.

If it is forced to curve with a small curvature, the above-mentioned problems will occur. This invention was made to solve these problems, and involves stripping the outer tube of one casing or the outer tube and inner tube at one end to expose the reinforcing steel wire, and removing the reinforcing steel wire from the exposed portion. The reinforcing steel wire is folded back onto the outer tube, and a synthetic resin liner member, in which a curved cable guide hole is separately formed, is temporarily engaged with the inner tube exposed at the end of the two casings so as to communicate with the inner tube. fixing the synthetic resin liner member;
A curved cable guide hole characterized in that the synthetic resin liner member and the folded end of the reinforcing steel wire are uniformly covered and a synthetic resin is applied and molded to form a synthetic resin cap. The present invention provides a method for manufacturing a conduit in which a synthetic resin cap is integrally attached to a casing.

In this invention, the synthetic resin liner member is made of polyamide, polyacetal, etc., which have excellent wear resistance and self-lubricating properties.
Thermoplastic polyester or high-density polyethylene is used, and these are blended with solid lubricants such as graphite, molybdenum disulfide, or tetrafluoroethylene resin powder, and lubricating oil such as mineral oil to improve performance. It is preferable that it not be improved. This synthetic resin liner member must be formed with an inner hole (formed as a cap and then a guide hole) having a predetermined radius of curvature and degree of curvature.

The present inventors have proposed a method of cutting a straight vibrator to an appropriate length and heating it to curve it, or inserting a flexible core into a similar straight vibrator and heating the entire vibrator to curve it. Later, we adopted a method of removing the core metal and achieved good results, but in order to eliminate irregularities in the shape of the inner hole and improve mass production, we obtained even better results by molding the liner member in a vertically divided shape. . In other words, the liner member is vertically divided into two parts completely symmetrically.
By molding into a segmented shape, or a shape where parts are vertically divided especially near the curved part, the molded product can be easily removed from the mold and workability can be improved. Therefore, it was possible to eliminate irregularities in the curved inner hole.

In order to join these divided pieces together, you can apply adhesive to the joining surfaces and join them together, or you can prepare small protrusions and small holes on the joining surfaces in advance so that they face each other, and then engage them and make them into one piece. In addition, methods such as fusion bonding of the joining surfaces using ultrasonic waves are employed. The joining of the divided pieces is temporary, and it is sufficient that the joining strength is such that it does not interfere with the next work.

The liner member thus obtained is temporarily fixed with its inner hole (guiding hole) communicating with the inner tube exposed at the end of the casing.

This temporary fixation is done by expanding the diameter of one end of the liner member or the exposed end of the inner tube and fitting them together, or by connecting the end surfaces of the liner member and the inner tube to each other. This is done by joining using an adhesive. This temporary fixation of both can be used to prevent them from coming off or shifting from the predetermined mounting position during adhesion molding with synthetic resin, and to allow attachment from the temporary fixation part of both. It is sufficient that the synthetic resin does not flow in and cause any damage to the inner hole (guiding hole).

After the liner member is temporarily fixed to the inner tube exposed at the casing end in this manner, the casing end and the liner member are placed in a mold, and a synthetic resin is applied and molded around them.

In this invention, a wide variety of known synthetic resins can be used as the synthetic resin used for the adhesion molding, but in particular, synthetic resins that are strong and have appropriate rigidity, such as reinforced synthetic resins such as glass fiber powder, etc. Polyamide resin compounded with base material,
ABS resin, high hardness urethane resin, thermoplastic polyester resin, etc. are preferred. The molded synthetic resin uniformly covers the periphery of the curved liner member and the end of the casing where the reinforcing steel wire is folded back to strengthen the end, and at the same time, connects the liner member and the casing together. , this is where the cap is constructed.

This cap consists of a base integrally attached to the end of the casing, a curved part curved with a predetermined curvature and degree of curvature with respect to the base, and an end connected to the curved part, The curved cable guide hole communicating with the cable guide hole of the casing is opened in the end surface of the end of the cap.

This curved cable guide hole does not mean that it is curved throughout the entire path from the part that communicates with the cable guide hole of the casing to the open end of the cap end; It is preferable to have a cable guide hole portion.

This linear guide hole portion has the role of reliably guiding the guide cable sliding inside the hole and smoothing power transmission in a predetermined direction.

In addition, it is desirable that the radius of curvature of the curved cable guide hole is as small as possible from the purpose of this invention, but this depends on the thickness (diameter) of the cable used and the thickness (diameter) of the casing. It depends on the direction.

In addition to these shape and configuration reasons, in general, as the radius of curvature of a curved cable guide hole becomes smaller and the degree of curvature increases, the transmission efficiency decreases even if the cable guide hole is not deformed such as cracks. The radius of curvature of the curved guide hole is determined by comprehensive consideration, taking into account the purpose of use, since this causes a decrease in the cable life and has a large effect on the life of the guide cable.

For example, a stranded steel wire with a diameter of 1 to 1.57 nm can be used as a conductor. Alternatively, in the case of using piano wire, the radius of curvature of the curved cable guide hole provided in the cap can be about 107T$L, and the degree of curvature can be about 90 degrees.

Even if the reduction in transmission efficiency is allowed to a certain extent, plastic deformation due to bending may occur in the conductor cable used. It goes without saying that the radius of curvature and degree of curvature should not be so high that it will cause the In any case, the guide cable repeatedly comes into strong sliding contact with this curved cable guide hole, so the radius of curvature and degree of curvature are
Not only transmission efficiency but also friction and wear will be considered.

Therefore, a cap having a curved guide hole made of a metal material is not preferable from the viewpoint of friction and wear, and is also undesirable because it produces sliding noise and has a poor sliding feeling.

Next, a preferred embodiment of the method for manufacturing a conduit according to the present invention will be described based on the drawings.

In FIG. 1, 1a is a synthetic resin liner member, 2 is an inner hole (guiding hole), and 3 is an enlarged diameter portion provided at one end of the member.

Figure 2 shows a synthetic resin liner member 1b consisting of two parts.
In the perspective view showing an example, 4 is a dividing surface portion. Figure 3A,
b is a side view and a plan view showing the synthetic resin liner member 1b shown in FIG.
The small protrusions 5 and the small holes 6 are provided at opposite positions, and when the divided surfaces 4 are brought together, they fit into each other and the divided pieces are temporarily fixed together. The liner member 1a shown in FIG. 1 is obtained by bending a straight synthetic resin vibrator or by injection molding it using a flexible metal core, and then removing the core metal.

The enlarged diameter portion 3 may be formed at the same time as injection molding, or may be formed by press-fitting a hot iron into the inner hole 2 to enlarge the diameter after bending. The liner member 1b shown in FIG. 2 is obtained by injection molding each divided piece using a mold.

The latter manufacturing method has the advantage of excellent molding workability. FIG. 4 shows yet another liner member 1c.

This liner member 1c is divided into two parts in the longitudinal direction at the curved part in consideration of workability when injection molding is performed using a mold, and consists of divided pieces 1d and 1e. Reference numeral 7 denotes a curved end portion that is not divided, and the outer diameter of the end portion 7 is larger than that of the curved portion.

Although the inner hole 2b opened in the end portion 7 is formed smaller than the curved portion inner hole 2 in the figure, the inner hole 2b may be formed larger than the curved portion inner hole 2. In the latter case (not shown), the guiding line may have a swivel function (
It is possible to have Swi■e1). In FIG. 5, a broken line portion 8 indicates a synthetic resin material that connects the end of the casing and the liner member together to form a cap portion.

FIG. 6 is a cross-sectional view illustrating a method for obtaining a cable conduit having the curved cap 9 shown in FIG.
1 is a synthetic resin injection hole, and C is a cavity, which is formed in the shape of the curved cap portion of the present invention.

D is a pin that closes the open end of the liner member and is fixed to the mold, and E is a support jig consisting of a support head Ea and a handle Eb, both of which are moved in the direction of the arrow after molding is completed. It is removed. 10 is a casing, 11 is an outer tube made of synthetic resin, 12a is a reinforcing steel wire, 12b is a folded end of the reinforcing steel wire, 13a is an inner tube made of synthetic resin, and 13b is its exposed end. Although the reinforcing steel wire 12a is drawn in a straight line in the figure, it actually consists of a plurality of reinforcing steel wires 12a wound around the outer periphery of the synthetic resin inner tube with a constant lead.

The synthetic resin outer tube 11 is the inner tube 1
It may be made of the same synthetic resin as 3a, or it may be made of a different kind of synthetic resin.

Although the casing 10 is constructed in this way, the synthetic resin cap attached to the end of the casing 10 cannot be simply attached by molding, even if the same synthetic resin as the outer tube 11 is used. too,
The close contact is not sufficient. In other words, complete fusion between the two cannot be expected. Therefore, the present inventors peeled off the end of the casing 10 to expose the reinforcing steel wire 12a, folded this exposed part back at an acute angle to form a folded end 12b, and included the folded end 12b. and forming a synthetic resin cap 9 to cover the end of the outer tube 11,
They succeeded in obtaining a cable conduit with extremely high adhesion strength (pulling resistance) between the two. The folded end 12b of the reinforcing steel wire preferably has a folded part 12c folded back at an acute angle and a folded part 12d further folded inward near the end.

It was confirmed that compared to the case where the synthetic resin cap and the synthetic resin outer tube are simply attached by molding, the pull-out resistance of both is approximately four times greater when the reinforcing steel wire has a folded end.

The conduit according to the present invention thus obtained is illustrated in FIGS. 7 and 8. Liner member 1a shown in FIG.
is temporarily fixed by fitting to the exposed inner tube end 13b of the casing, and the liner member 1b shown in FIG.
3b and is temporarily fixed by adhesive.

After such temporary fixation, the support jig E is inserted into the temporary fixation part from the other end, and the synthetic resin cap part 9 is formed by molding. Note that FIG. 8 shows a mode in which the liner member 1b does not reach the open end of the cap member 9. As described above, according to the present invention, it is possible to change the direction of the strength of the synthetic resin curved conductor, especially at the end of the cable conduit, without straining the casing part, which is difficult to curve due to its structure. This can be effectively accomplished by providing a synthetic resin cap portion that is firmly fixed to the liner member having the hole.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing one embodiment of a synthetic resin liner member having a curved guide hole according to the present invention, FIG. 2 is a perspective view of another embodiment of the member, and FIGS. FIG. 2 is a side view and a plan view showing the synthetic resin liner member divided at the dividing plane, FIG. 4 is a perspective view showing still another embodiment of the liner member of the present invention, and FIG. 4 is a vertical cross-sectional view, FIG. 6 is a partial vertical cross-sectional explanatory view showing an embodiment of the method of molding a synthetic resin curved cap of the present invention, and FIGS. FIG. 2 is an explanatory diagram of a vertical cross-sectional structure of a synthetic resin curved cap portion and a casing portion manufactured in this manner. 1a, 1b, 1c...liner member, 2...
...Inner hole, 9...Cap, 10...
・Casing, 11...Outer tube, 12a
...Reinforced steel wire, 12b...Folded end, 13a...Inner tube.

Claims (1)

[Claims] 1 The reinforcing steel wire exposed at one end of the casing consists of an inner tube with a cable guiding hole, a reinforcing steel wire wound around the outer circumference of the inner tube, and an outer tube covering the inner tube and the reinforcing steel wire. folding it back onto the outer tube; aligning the end of the casing and one end of the liner member in which the curved cable guide hole is formed so that the two cable guide holes communicate with each other; A method for manufacturing a cable conduit comprising the step of applying a synthetic resin to the folded portion of the reinforcing steel wire.