JPH0847981A - Method and apparatus for molding resin tube - Google Patents

Abstract

PURPOSE:To properly mass-produce a resin tube by adapting a press molding method using an open mold clamping an upper mold (male mold) and a lower mold (female mold). CONSTITUTION:In molding a resin tube 4', the male mold 2 provided with respect to a female mold 1 in an up and down movable manner is allowed to fall to clamp both molds 1, 2 and the molten resin 4 charged in the female mold 1 is compressed to mold a tube outer shape and a tube hollow part is molded by the core 3 horizontally provided in the female mold 1. A resin tube molding apparatus consists of the female mold 1 molding the almost lower half part of the total length of the tube, the male mold 2 provided in an up and down movable manner and allowed to fall to compress the molten resin 4 charged in the female mold 1 to mold the upper half part of the total length of the tube and the core 3 horizontally provided in the female mold 1 in a detachable manner to mold the hollow part of the tube 4'.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin tube molding method capable of producing a resin tube by applying a press molding method and a molding apparatus used therefor.

[0002]

2. Description of the Related Art Resin tubes typified by fuel supply tubes for vehicles are molded by blow molding or injection molding. However, in blow molding, the plate thickness is uneven and it is difficult to mold large tubes. is there. On the other hand, in the injection molding method, it is possible to mold a large tube, but there is a problem that the molding machine is large and the equipment cost increases.

[0003]

According to the present invention, as means for solving the above problems, a male mold which is vertically movable with respect to a female mold is lowered and clamped to charge the female mold. The idea is to compress the molten resin to mold the outer shape of the tube, and to mold the hollow part of the tube with the core horizontally installed in the female mold so that the tube can be produced by applying the so-called press molding method and equipment. It was done.

The molten resin is extruded from an extruder and charged into the female mold through a nozzle. Alternatively, it does not prevent manual charging of the molten resin.

The molten resin is charged so as to rise around the core, or preferably to rise above the upper surface of the core. The molten resin charged on the upper surface of the core is compressed by the downward movement of the male mold to mold the upper half of the entire tube length by the male mold and the core, and a part of the molten resin compressed by the male mold is compressed. It is made to flow between the male mold and the core by force and gravity to mold the lower half part of the entire tube length.

That is, the molten resin is compressed by lowering and clamping the male die with respect to the female die, and the annular molding space around the core surrounded by the female die and the male die is filled with the molten resin. After the molten resin is cured, the male mold is opened (raised) and the core is removed to mold the resin tube.

The core is installed so that it can be removed from the side surface of a female mold, for example.

Further, as a means for preventing the deformation of the core when the male mold is clamped, a support member for receiving the core is provided.
The core support member is made to be operable at a core support position and a position where the support is released and the core mold is released from the female molding cavity. As a result, the core support member escapes from the molding cavity of the female mold before the molten resin reaches the support member, and the molding of the lower half of the tube is performed without any hindrance.

[0009]

As described above, according to the present invention, the resin molding can be properly mass-produced by applying the press molding method using the open mold in which the upper mold (male mold) and the lower mold (female mold) are clamped.

According to this method, it is possible to fill the annular space around the core defined by the mold clamping of the female mold and the male mold with the molten resin and to produce a uniform resin tube.
Eliminates unavoidable uneven thickness in blow molding.

Further, the equipment cost can be reduced without increasing the size of the apparatus such as injection molding, and the material yield is good.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIGS. 1 and 2, a press-molding apparatus for a resin tube comprises a female mold 1 for molding the lower half of the entire tube length, and a male mold 2 for molding the upper half of the total tube length. , A core 3 detachably provided inside the female mold for molding the hollow portion of the tube.

The male mold 2 is provided so as to be movable up and down by a cylinder, a crank mechanism, etc., and is shown in FIGS. 1A, 2A and 1B.
As shown in FIG. 2B, the molten resin 4 charged on the upper surface of the core 3 in the female mold 1 is compressed by descending to compress the male mold 2 and the core 3.
Molding the upper half of the tube length between
As shown in FIG. 4, the male resin 2 is compressed to flow the molten resin 4 between the core 3 and the female mold 1 to mold the lower half of the entire tube length.

That is, the male mold 2 and the female mold 1 are clamped to form an annular molding interval 5 surrounded by the molds 1 and 2 around the core, and the annular molding interval 5 is filled with the molten resin 4. A resin tube 4'is molded.

The female mold 1 is formed by penetrating one side wall of the female mold 1.
A core insertion / extraction hole 6 opened on the outer side surface and the inner side surface (inner surface of the molding cavity), the core 3 is inserted through the core insertion / extraction hole 6, and the tip faces the side wall provided with the insertion / extraction hole 6. Insert it in the mortise 7 provided on the side wall to support it.

Thus, in the core 3, between the insertion / removal hole 6 and the mortise hole 7, the portion for molding the hollow portion of the tube is placed horizontally in the molding cavity of the female die 1, and both ends thereof are connected to the insertion / removal hole 6 and the mortise / recess. Hole 7
It is closely supported on the inner surface of the.

The base end of the core 3 is projected to the outside of the insertion / removal hole 6 for use in the insertion / removal work. Further, a tenon 8 is provided at the tip of the core 3 so as to have a step, and the tenon 8 is inserted into the mortise hole 7, and the step surface is brought into contact with the opening surface of the mortise hole 7 to insert the core 3 Then, the hollow molding portion of the core 3 is horizontally placed at a fixed position in the molding cavity of the female die 1.

A molding interval 9 on a substantially semi-circle for molding the lower half of the tube 4'between the female die 1 and the core 3 by this horizontal mounting.
In addition, the peripheral side wall of the female die 1 is erected above the core 3 to form a male fitting empty portion 10 communicating with the molding gap 9.

That is, the molding cavity of the female die 1 has an inner bottom surface of an arc shape, and has left and right and front and rear male guide portions 1b which are vertically and parallelly erected from the arc shape portion 1a, Open at the top. The outer shape of the molding interval 9 is defined by the arcuate portion, and the male fitting empty portion 10 that opens at the upper portion is defined by the male guide portion 1b, and the male die 2 is formed from the female opening portion. The four side surfaces are fitted while slidingly contacting the guide portion 1b, and the molten resin 4 charged on the upper surface of the core 3 is compressed.

The male mold 2 forms a semicircular molding interval 11 with the core 3 at the bottom dead center, and the molding intervals 11 and 9 form an annular molding interval 5 around the core 3.

As described above, the molten resin 4 charged on the upper surface of the core 3 descends from the male mold 2 and is clamped to the female mold 1 to form a molding gap 11 between the male mold 2 and the core 3. While being compressed and expanded inside, it is flowed into the molding interval 9 by the compressive force and fills the annular molding interval 5.

Then, after the mold clamping of the female mold 1 and the male mold 2 is maintained for a required time to promote the hardening of the molten resin, the male mold 2 is lifted to open the molding cavity in the female mold and the core. 3 is removed and the tube is taken out from the upper opening of the female mold.

As shown in FIGS. 1A and 2A, a charge arm 12 is provided at the exit of the ruder, a charge nozzle 13 is provided at the tip of the charge arm 12, and the charge nozzle 13 is moved in and out of the mold clamping surface area. 1A and 2A, the nozzle 13 is moved into the upper mold clamping surface area of the female mold 1 as shown in FIGS. 1A and 2A. The hollow molding part is moved from one end P1 point to the other end P2 point along the axis of the core 3, and the upper surface of the core 3 is charged with the molten resin over substantially the entire length of the hollow molding part of the core.

Molten resin 4 raised on the upper surface of the core
Are compressed with male mold 2.

The core 3 clamps the male mold 2 to receive the molten resin 4. As a means for preventing the core 3 from being deformed by the load receiving, a core support member 14 that supports the middle of the core 3 in the female mold 1 is provided. The core support member 14 is formed of, for example, a support pin, which vertically penetrates the bottom wall of the female die 1 and is opened at the outer surface of the bottom wall and the inner bottom surface of the molding cavity, that is, the inner surface of the molding space 9. It is inserted in 15, and the bottom of the core 3 is supported by the tip thereof.

That is, the core support member 14 is vertically inserted from the bottom wall of the female die 1 and the tip thereof is projected into the molding space 9 to form the core 3.
Support the middle part of.

The core support member 14 is vertically movable so as to vertically support the core 3 when the molten resin 4 is compressed by the male mold 2 as shown in FIGS. 1AB and 2AB. The resin flows into the molding gap 9 between the core 3 and the female die 1 and is lowered immediately before reaching the support member 14 to be retracted from the inner surface of the molding gap 9 (the inner bottom surface of the female die 1).

Preferably, the tip end surface of the core support member 14 (core support surface) is lowered and retracted to a position substantially flush with the inner bottom surface of the female die 1, and the molten resin flows into the support member insertion hole 15. Prevent.

The support member guide hole 15 can function as a means for letting air in the female die 1 escape when the male die 2 and the female die 1 are clamped. That is, the molten resin has an annular molding interval of 5
The air is discharged from the slit between the support member 14 and the guide hole 15 as the above condition is satisfied.

As means for moving the core support member 14 downward and backward in synchronism with the downward mold clamping operation of the male mold 2, FIG.
As shown in FIG. 2, a pair of sensing pins 16 are vertically provided at the left and right outer sides of the molding cavity of the female die 1.
Insert from the lower surface of the female mold and project the tip to the same upper surface,
The left and right outer surfaces of the molding portion of the male mold 2 are opposed to each other. The sensing pin 16 is connected to the core supporting member 14 via a connecting frame 17 so as to move up and down integrally with the core 1 in the lower part of the female die 1, and an assembly of the core supporting member 14 and the sensing pin 16 is supported by a cushion member 18. To do.

The sensing pin 16 is pressed against the cushion material 18 when the male die 2 is lowered, and in conjunction with this, the core support member 14 is lowered, and at the above timing, it is lowered from the molding interval 9 and retracted. .

The male die 2 presses the sensing pin 16 just before the descending dead center (immediately before the end of the mold clamping), and completes the retreat at the descending dead center.

As the cushion member 18, a spring or an air cushion is used.

As shown in FIG. 3, the core support member 14 can be vertically moved in timing by an air or hydraulic cylinder or other driving means without using the sensing pin 16.

A plurality of core support members 14 may be provided so as to support one part or two or more parts as long as they support the middle of the portion extending into the female mold 1.

FIGS. 4 and 5 show a male mold 1 for molding both ends of the tube 4'in the molding method and apparatus shown in FIGS.
9 shows an example in which 9 is provided.

The male mold 2 is formed by molding the outer shape of the upper half part of the intermediate portion other than the both ends of the tube 4 ', and the male mold 19 at the end is perpendicular to the left and right side surfaces of the vertically movable male mold 2. It is attached so that it can move up and down, and as shown in FIGS. 4A and 5A, it projects downward from the molding surface of the male mold 2 before mold clamping.

In this state, the charge nozzle 13 is moved from the point P1 to the point P2, and the molten resin 4 is placed on the upper surface of the core 3.
Is charged, and after the charging, the male mold 2 and the end male mold 19 are integrally lowered, and the female mold 1 is clamped. At this time, as shown in FIGS. 4B and 5B, the end male mold 19 is
Prior to the male die 2, the hollow molding portion of the core 3 is fitted into the male fitting empty portions 10 of the female die 1 at both ends thereof, and the core 3 is compressed prior to the compression of the molten resin 4 by the male die 2. A tube end molding interval 20 is formed between the end male mold 19 and the end male mold 19.

After the tube end molding gap 20 is formed by the end male die 19, the molten resin 4 is compressed by the male die 2. By this compression, the molten resin 4 is expanded at the interval 11 between the male mold 2 and the core 3, and the upper half of the tube middle portion is molded. Furthermore, as shown in FIGS. A part of the resin flows into the molding space 20 defined by the end male mold 19 and at the same time into the molding space 9 between the female mold 1 and the core 3 to mold the lower half of the tube and both ends. Done.

The male mold 2 has an arcuate molding surface 2a for molding the upper half of the tube, but it is not possible to manufacture both end edges of this arc forming surface 2a at an acute angle (processing into a shear edge). Is difficult, and as shown in FIG. 6, it is unavoidable to form a flat surface 21 having a minimum length of about 1 mm on the both edges.

This flat surface 21 projects into the annular space around the core during mold clamping and bites into the molten resin to form an axial step on the side surface of the tube, impairing the roundness of the outer shape of the tube.

The end male mold 19 shown in FIGS. 4 and 5 prevents the step from occurring at least at both ends of the tube.
Ensure perfect roundness at both ends of the tube.

The above-mentioned end male mold 19 has a molding interval 20 formed around both ends of the core 3 in advance, and thereafter the male mold 2 compresses the molten resin 4. This differential operation is performed. As a means for making it possible, for example, the end male mold 19 is supported by a cushion material 22 and is made to stand by in a state of protruding downward from the molding surface of the male mold 2, and when descending, as shown in FIG. 4BC and FIG. The lower end surface of 19 is abutted against the inner bottom surface of the female die 1 to set the descending dead center.

After that, only the male mold 2 descends to compress the molten resin 4, and the male mold 19 at the end of this interval is the cushion member 22.
While compressing, the lowering amount of the male mold 2 is absorbed and the mold clamping state is maintained.

Instead of the cushion member 22, the end male mold 19 can be preliminarily operated in timing by using an air cylinder or a hydraulic cylinder.

[0046]

INDUSTRIAL APPLICABILITY The present invention makes it possible to produce a resin tube by applying a press molding method using an open mold.

According to the present invention, the molten resin can fill the molding interval around the core defined by the mold clamping of the female mold and the male mold with the molten resin to produce a uniform resin tube,
Eliminates unavoidable uneven thickness in blow molding.

Further, the apparatus size such as injection molding does not become large, the equipment cost and the maintenance cost can be greatly reduced, and the material yield is extremely good.

Further, by using the male end portions together, it is possible to prevent burrs and steps from being formed in the tubular portions at both ends which are used as the connecting portions of the resin tube, etc., and ensure the roundness.

By providing a core support member,
This effectively prevents the deformation of the core and the resulting deformation of the tube during mold clamping, and is effective in molding a relatively long resin tube.

[Brief description of drawings]

1A, 1B, and 1C are vertical cross-sectional views showing, in the order of operation, a method and apparatus for molding a resin tube as an example of the present invention.

2A, 2B, and 2C are cross-sectional views showing a method of molding the resin tube and an apparatus in the order of operation.

FIG. 3 is a cross-sectional view showing a molding method and apparatus without using the sensing pin in FIGS.

4A, 4B, and 4C are vertical cross-sectional views showing, in the order of operation, a method and apparatus for molding a resin tube as another embodiment of the present invention.

5A, 5B and 5C are cross-sectional views showing a method of molding the resin tube and an apparatus in the order of operation.

FIG. 6 is a cross-sectional view of a male molding part.

[Explanation of symbols]

 1 Female 2 Male 3 Core 4 Molten Resin 4'Resin Tube 5 Annular Molding Interval 6 Core Insertion / Extraction Hole 7 Mortise Hole 8 Mortise 9 Molding Interval 11 Molding Interval 20 Molding Interval 10 Male Molding Void 14 Core Support member 16 Male type sensing pin 19 Male end type

Claims (4)

[Claims] 1. A male mold, which is vertically movable with respect to a female mold, is lowered to clamp the molten resin charged in the female mold to mold the outer shape of the tube. A method for molding a resin tube, characterized in that a hollow portion of the tube is molded by a horizontally arranged core. 2. A core surrounded by a female mold and a male mold by horizontally placing a core in a female mold, charging a molten resin on the upper surface of the core, and compressing the molten resin with a male mold. A method for molding a resin tube, characterized in that an annular molding interval around a child is filled with the molten resin, and after the molten resin is cured, the male mold is opened and the core is removed. 3. A female die for molding a substantially lower half portion of the entire tube length, and a male die for vertically moving and molding an upper half portion of the entire tube length for compressing molten resin charged in the female die when descending. An apparatus for molding a resin tube, comprising: a mold; and a core detachably provided inside the female mold for molding the hollow portion of the tube. 4. A core support member is provided which operates in a position for supporting a core horizontally provided in the female mold and a position for releasing the support and escaping from a molding cavity in the female mold. The resin tube molding apparatus according to claim 3.