JP2992758B2 - Focusing and fixing of small resin tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention uses a plurality of small-diameter resin tubes used as pipes for lubrication, air supply, and the like for an automobile or various mechanical devices as a base. The present invention relates to a convergence fixing method for enabling piping to be collectively concentrated so that attachment is convenient or the interval is kept constant.

(Prior art) Conventionally, most of these types of pipes use metal thin pipes with an outer diameter of about 20 mm or less. This is done by setting a plurality of small-diameter metal tubes in parallel on a jig, and brazing the adjacent metal tubes directly to each other or by brazing them through appropriate fittings. Was. In addition, a plurality of parallel metal tubes are inserted into a mold having a cavity of an appropriate shape, and molten resin is injection-molded into the mold to simultaneously form a mounting piece and fix the metal tube. Widespread methods were also used.

(Problems to be Solved by the Invention) However, in recent years, due to the demand for weight reduction, there has been an increasing tendency to adopt a small-diameter resin tube using a synthetic resin such as nylon. Although some results have been obtained when the pipes are formed of metal pipes, the former method cannot be adopted at all when the pipes are resin tubes, and in the latter method, This is an extremely rational method because injection molding can be used to mold the tube mounting pieces such as brackets and spacers and attach and fix the resin tube to the tube at a glance. The resin tube disposed in the mold is softened and deformed by the heat and injection pressure of the molten resin injected during the injection molding, and the resin tube fixed by the solidification of the injected resin. Even if the tube of the tube is crushed or not collapsed, the tube is significantly deformed and cannot maintain a predetermined hole diameter. In fact, satisfactory results have not been obtained.

SUMMARY OF THE INVENTION An object of the present invention is to effectively solve the above-described problems in performing convergence and fixing when a small-diameter resin tube is used as various types of piping.

(Means for Solving the Problems) In order to achieve the above object, a method for converging and fixing a small diameter resin tube according to the present invention is such that a metal core made of a metal bar or a metal tube is detachable over its entire length in advance. In a state in which a plurality of inserted small-diameter resin tubes are arranged in parallel at a predetermined interval, they are inserted through a mold having a desired cavity and directly set in the mold, and are melted in the cavity. The desired position of the parallel resin tube is fused and fixed by the solidified resin body after cooling and solidifying after injecting the thermoplastic resin, and thereafter, the core is pulled out from the small-diameter resin tube, Preferably, the cored bar is formed of a metal tube, and a coolant is preferably passed through the core.

According to the present invention, since the core metal is previously inserted into the resin tube, the injection pressure does not cause the resin tube to be crushed or deformed even when the high-temperature thermoplastic resin is injected into the mold. Also, the original pipe diameter can be accurately maintained.

(Operation) The details of the present invention and the operation thereof will be described below with reference to the accompanying drawings. FIG. 1 shows a method for focusing and fixing a small-diameter resin tube according to the present invention after injection of a thermoplastic resin in a mold. FIG. 2 is a cross-sectional view showing a state,
In the figure, reference numeral 1 denotes a small-diameter resin tube which forms different flow paths such as oil and gas. As shown in FIGS. 2A and 2B, a metal rod 2 having an outer diameter slightly smaller than the inner diameter or a metal core 2 made of a metal tube is preliminarily inserted into the small-diameter resin tube 1 so as to be removable.

Reference numerals 3 and 3 'denote molds in which cavities 4 are formed so that mounting pieces having appropriate shapes such as a spacer shape and a bracket shape are injection-molded. The molds 3 and 3 ′ are provided with an injection port 5 for injecting the molten thermoplastic resin into the cavity 4 and a cooling water channel 6, and are injected and filled into the cavity 4 from the injection port 5. The thermoplastic resin 7 is formed so as to be rapidly cooled and solidified in the cavity 4.

In the present invention, when the bundle of the small-diameter resin tubes 1 is fixed, the core metal 2 is first inserted into a plurality of small-diameter resin tubes 1 to be focused and fixed. A metal rod or tube made of stainless steel or copper is used for the cored bar 2. In each case, the outer diameter is slightly smaller than the inner diameter of the small-diameter resin tube. It is important that the outer peripheral surface is made removable so that it can be pulled out smoothly by, for example, applying a finish release agent smoothly.

When a metal tube is used as the core metal, pipes for flowing refrigerant are connected to both ends of the metal tube, and a coolant such as water, air or brine is injected into the tube during injection molding of the molten resin into the mold. Forced circulation is practically extremely effective in preventing softening deformation of the resin tube 1 and is extremely important in shortening the molding cycle time and improving productivity.

A plurality of the small-diameter resin tubes 1 into which the cored bar 2 has been inserted in this manner are arranged in parallel in a plane or three-dimensional form at a desired interval, and if necessary, are arranged in an arrangement state by a suitable jig or the like. It is temporarily fixed so as to keep it, and the desired part is inserted and fixed in the dies 3, 3 'so as to be collectively clamped in the width direction. Next, the thermoplastic resin that has been heated and melted is injected into the cavity 4 formed in the molds 3 and 3 ′ through the injection port 5 to fill the cavity 4 and supply cooling water to the flow passage 6 to cool the metal. When the thermoplastic resin in the mold is cooled and solidified, the thermoplastic resin 7 is solidified so as to be fused around the small-diameter resin tube 1. After cooling, the injection molded product integrated with the small-diameter resin tube 1 is taken out from the molds 3 and 3 ', and the core 2 is pulled out from the small-diameter resin tube 1 to complete the operation.

Since the method for converging and fixing the small-diameter resin tube of the present invention is performed by the above-described method, when the thermoplastic resin melted at a high temperature is injected into a mold in which the small-diameter resin tubes are sandwiched in parallel, the method is performed. Since the metal core is inserted into the diameter resin tube, it is not crushed by the injection pressure and the pipeline is closed or deformed and the pipeline diameter is not changed. The resin tubes arranged in parallel can be securely fixed to the mounting piece.

In particular, when a core metal is used for a metal tube to allow a coolant such as water or brine to pass therethrough when injecting a thermoplastic resin, the injected resin is cooled more than the mold alone. This is very effective because it is performed promptly, so that deformation due to softening of the small-diameter resin tube is completely prevented, and productivity is enhanced by its cooling effect.

The thermoplastic resin used for injection molding in the present invention is not particularly limited, and any synthetic resin such as polyethylene, polypropylene, polyacetal, and ABS resin can be used.

Next, an example of a method for focusing and fixing a small-diameter resin tube according to the present invention will be described.

(Example) Inner diameter 6.0mm, outer diameter 8.0mm cut to desired length respectively
As shown in FIG. 3, three nylon (PA11) thin resin tubes 1a made of nylon (PA11) and one nylon (PA12) thin resin tube 1b having an inner diameter of 10.0 mm and an outer diameter of 12.0 mm as shown in FIG. In obtaining a convergence fixed body having a bracket-like mounting piece 8 and spacer-like mounting pieces 8 'near both ends,
A metal rod made of copper having a diameter slightly smaller than its inner diameter and having a surface roughness of 3 μm or less is inserted in the small-diameter resin tube 1a in a state where a silicone-based release agent is applied to the surface and inserted. On the other hand, the small-diameter resin tube 1b has a diameter slightly smaller than its inner diameter and a surface roughness of 3 μm inside.
The following stainless steel pipe was coated with a silicone-based mold release agent on the surface and inserted, and at the same time, cooling water was supplied to the inside to form bracket-shaped and spacer-shaped cavities at predetermined locations. A molding die is placed and a small-diameter resin tube parallel to it is clamped. Then, polypropylene (PP) resin melted at a temperature of 165 ° C is injected from the injection port of the die with a mold internal pressure of 250 kgf / cm ^2. The resin injected into the cavity was solidified by injecting it into the cavity and subsequently supplying cooling water to the water passage of the mold, and then the core metal inserted into the destination from the mold was removed. From the small diameter resin tube to obtain a fixed bundle.

Each of the small-diameter resin tubes 1a and 1b of the obtained fixed bundle is securely fixed by respective mounting pieces 8 and 8 ', and the inner diameter thereof is maintained substantially constant at any point. It was confirmed that the road was not deformed.

(Effects of the Invention) As described above, when the method of the present invention is used to form a mounting piece such as a bracket and to fix and fix a small-diameter resin tube to the mounting piece using an injection molding method, Since the metal core is placed in the resin tube inserted and placed in the mold, deformation of the resin tube due to the injection molding operation can be prevented beforehand. When circulating the refrigerant appropriately,
This is an extremely effective invention because not only the deformation preventing effect is outstanding, but also the productivity is improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a state of a mold in an injection molding state in a method of converging and fixing a small-diameter resin tube according to the present invention, and FIGS. 2a and 2b are portions showing a small-diameter resin tube with a core inserted. FIG. 3 is a plan view showing an example of a convergence fixing body obtained by the convergence fixing method of the small-diameter resin tube of the present invention. 1, 1a, 1b: small-diameter resin tube, 2: core metal, 3,
3 ': mold, 4: cavity, 5: injection port, 6: cooling water flow path, 7: thermoplastic resin, 8, 8': mounting piece.

Claims (4)

(57) [Claims] 1. A mold having a desired cavity in a state in which a plurality of small-diameter resin tubes into which a core metal has been inserted so as to be able to be removed in advance over the entire length thereof are arranged in parallel at a predetermined interval. The molten resin is injected into the cavity and solidified by cooling.Then, the desired position of the parallel resin tube is fused and fixed by a solidified resin body. A method for focusing and fixing a small-diameter resin tube, comprising extracting gold from the small-diameter resin tube. 2. The method according to claim 1, wherein the core is a metal bar. 3. The method according to claim 1, wherein said core metal is a metal tube. 4. The method according to claim 3, wherein a refrigerant is passed through the metal tube.