JP4437601B2 - Method for producing hollow molded body - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention belongs to the technical field of side-shaped blinkers and headlamps attached to automobile bodies, and hollow molded articles such as tail lamps and side mirrors, and methods for producing the same.
[0002]
[Prior art]
In general, as an example of this kind of hollow molded body, there is a side blinker as a lamp provided so that, for example, the bending direction of the vehicle can be visually recognized from the side of the body. Such a side blinker is formed by molding a lens part made of a translucent material and a housing in which a light bulb is incorporated as a primary product, and then fixing these primary products together. However, for example, a die slide injection method is known as a manufacturing method of such a device. In this method, for example, as described in Japanese Examined Patent Publication No. 2-38377, each primary product is molded (primary molding) in a state where the movable mold and the fixed mold are opposed to each other, and then the movable mold is slid. The two primary products are moved together to meet each other, and a secondary injection material is secondarily injected to the butt surface portion to mold the product (secondary molding).
By the way, in this case, the injection material is secondarily injected and integrated into the filling chamber (injection chamber) secured in the abutting surface portion of the abutted primary products. It is necessary to form a guide path, i.e., a sprue and a runner, for guiding the injection material secondarily injected from the tip to the filling chamber, and to perform secondary injection via the sprue.
[0003]
[Problems to be solved by the invention]
In this way, the injection material is secondarily injected and the primary products are integrated to produce a hollow molded body. In the conventional one, the secondary injection material is formed on the sprue formed on the mold side. As a product, it becomes a sprue runner that protrudes from the hollow molded body. Therefore, as a product, it is necessary to cut this sprue runner, and the cut sprue runner is discarded as a waste member. In some cases, the resin material is recycled, but in any case, there is a problem that the yield of the resin material is deteriorated.
Therefore, for example, as disclosed in Japanese Patent Laid-Open No. 7-68601, it has been proposed to achieve a sprue runnerless by forming a hollow molded body using a runnerless mold. In order to make the sprue runner-less, a special mold or injection nozzle is required, resulting in high costs and problems of versatility. This is a problem that the present invention does not solve.
[0004]
[Means for Solving the Problems]
The present invention was created to solve these problems in view of the above-described circumstances, and after the primary injection of each half-shaped primary product into a fixed mold and a movable mold, the molding was performed. The movable mold side is moved so that the primary product on the movable mold side is butted against the primary product on the fixed mold side, and then the injection material is secondarily injected into the filling chamber provided in the butting portion to form a hollow molded body. In the method for manufacturing a hollow molded body, the one primary product is formed with a through hole communicating with the filling chamber, and the tip of the injection nozzle for secondary injection of the injection material is provided with the protrusion. When the resin material is secondarily injected by abutting against the through hole of the combined primary product and using the through hole as a sprue, the through hole serving as the sprue is a valve provided in an injection nozzle for secondary injection. this formed by the gate pin Which is a method for producing a hollow molded article characterized.
And by doing this, the through hole formed in the primary product functions as a sprue that guides the secondary injection material to the filling chamber. The sprue runner-less without using it can be achieved.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings. In the drawings, 1 is a side blinker which is an example of a hollow molded body, and the side blinker 1 includes a lens portion 2 and a housing 4 in which a light bulb 3 is incorporated. The primary product, which is a half product, is molded by primary injection in the fixed mold and the movable mold. After sliding the movable mold, the primary products are brought into contact with each other. It is manufactured by a conventionally known die slide injection method in which an appropriate injection material 5 such as a resin is secondarily injected into the filling chamber S to be formed. Since the slide injection method can be employed as it is in the present invention, its details are omitted.
[0006]
The lens portion 2 formed by the primary injection molding has a substantially bowl shape, and the peripheral edge portion 2 a is abutted and brought into contact with the hook-shaped portion 4 a formed on the outer peripheral edge of the housing 4. In the present embodiment, the space having the step surface between the side surface of the housing 4 of the lens peripheral portion 2a and the outer end surface of the housing flange 4a is the filling chamber S for the resin material 5 to be secondarily injected. . A through hole 2b communicating with the filling chamber S is formed in the lens peripheral edge 2a. The through hole 2b is formed in the primary injection process as follows, for example.
[0007]
Several methods can be considered for the formation (opening) of the through hole 2a. First, as a first embodiment, a method using a valve gate pin 7 provided in an injection nozzle 6 for performing secondary injection. It is. In other words, as shown in FIG. 2 (A), in this case, the tip of the injection nozzle 6 for secondary injection is used as one mold (fixed mold) 8 at the stage of molding the lens unit 2 by primary injection. In this case, a valve karate pin 7 for opening and closing the injection nozzle 6 is projected from the tip of the nozzle and abutted against the other mold (moving mold) 9, and in this state, the primary The lens portion 2 is formed by performing injection (the primary injection is performed using an injection nozzle for primary injection (not shown) different from the injection nozzle 6 for secondary injection). Incidentally, in the course of this primary injection, the housing 4 is also simultaneously molded by a mold (not shown). Next, secondary injection is performed in a state where the molded lens portion 2 and the housing 4 are abutted with each other. As shown in FIG. And the injection nozzle 6 for secondary injection is opened, the secondary injection material 5 is injected in this open state, and after the injection, as shown in FIG. Is projected so that the tip is located in the hole length range X of the through-hole 2b, and the secondary injection material 5 is cured (cured) in this state.
Incidentally, when the through hole 2b is formed, the valve gate pin 7 is not abutted against the other mold 9 but is formed in the guide hole 9a formed in the other mold 9 as shown in FIG. It can also be formed by fitting.
[0008]
As described above, in the first embodiment in which the present invention is implemented, when the secondary injection is performed and the lens portion 2 and the housing 4 are integrated to form the side blinker 1, the primary injection is performed. The through-hole 2b formed in the lens unit 2 functions as a sprue (runner) for guiding and flowing the propellant 5 at the time of secondary injection, that is, as a result. In addition, since there is no sprue runnerless, there is no need to use a special mold. In addition, since the through hole 2b is formed by using the valve gate pin 7 for opening and closing the injection nozzle 6 for secondary injection, the valve gate pin 7 is formed rather than normally closing the nozzle. The structure that protrudes long, that is, only the movement stroke of the valve gate pin 7 has only to be lengthened, and the structure is not particularly complicated.
In this case, it is preferable that the lens portion 2 side is the fixed side and the housing 4 is the movable side because it is not necessary to move the injection nozzle 6 for secondary injection.
[0009]
On the other hand, the present invention can also be implemented as in the second embodiment shown in FIG. That is, in this case, when the lens portion 2 is primarily emitted, the core pin 10 for forming the through hole 2b is provided on the mold 9 side opposite to the side where the injection nozzle 6 for secondary injection is set, The secondary injection material 5 is injected by using the through-hole 2b formed by the core pin 10 as a sprue. In this case, as shown in FIG. 4, the tip of the core pin 10 can be abutted against the valve gate pin 7 of the injection nozzle 6 for secondary injection. As in the case of the first embodiment, the injection nozzle 6 set in advance can be opened by making the valve gate pin 7 immerse and the secondary injection can be performed, and the molding can be speeded up.
[0010]
The present invention is not limited to the above embodiment, and the side for opening the through hole may be on the housing 4 side as in the third embodiment shown in FIG. When the through-hole 4b is formed on the housing 4 side, the through-hole 4a is hidden and cannot be seen from the outside when attached to the vehicle as a product. And since this is a flat surface where the tip of the secondary injection nozzle abuts, the valve gate pin is inserted into the hole of the through hole after the secondary injection as in the case where it strikes the inclined surface of the above embodiment. In the cured state, the distal end surface of the valve gate pin and the housing surface are in a parallel state, which is convenient because it does not give a sense of incongruity.
[0011]
When trying to implement such a configuration that strikes the flat surface on the lens side, it can be implemented by the fourth and fifth embodiments shown in FIGS. 6 (A) and 6 (B). That is, in these devices, the peripheral edge portion 2a of the lens portion 2 is made flat, and a through-hole 2a is formed here to form a flat gate. In particular, the device shown in FIG. The portion is further formed into a concave groove 2c having a flat bottom surface, and a through hole 2B is formed therein. By doing so, the secondary injection material 5 flows into the surface of the lens portion 2 when performing secondary injection. Can be prevented.
[0012]
Further, in each embodiment shown in FIG. 7, the filling chamber S is set so as not to be exposed to the outside. In this case, the through holes 2b and 4b are formed on the lens portion 2 side and the housing 4 side. Can be made. And in these things, since the filling chamber S is hidden inside and is not exposed, only the butting of the lens portion 2 and the housing 4 is achieved, and the appearance is improved.
[Brief description of the drawings]
FIG. 1A is a side sectional view of a side blinker, and FIG. 1B is an enlarged sectional view of a main part.
FIGS. 2A and 2B are enlarged views of a main part showing a mold state when the lens part is primarily emitted, respectively.
3A is an enlarged view of a main part showing a state of secondary injection, and FIG. 3B is an enlarged view of a main part showing a state after the secondary injection.
FIG. 4 is an enlarged view of a main part showing a state when the lens part showing the second embodiment is primarily emitted.
FIG. 5 is a main part enlarged view showing a state in which a housing showing a third embodiment is primarily injected.
6 (A) and 6 (B) are enlarged views of a main part having a driving factor in the fourth and fifth embodiments. FIG.
FIGS. 7A to 7C are enlarged views of main parts of a side blinker showing further seventh to ninth embodiments; FIGS.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Side blinker 2 Lens part 2b Through-hole 4 Housing 4b Through-hole 5 Secondary injection material 6 Secondary injection nozzle 7 Valve gate pin

Claims (1)

After primary injection of each half-shaped primary product between the fixed mold and the movable mold and molding, the movable mold is moved and the primary product on the movable mold side is matched with the primary product on the fixed mold side. In the method for manufacturing a hollow molded body in which the injection material is secondarily injected into the filling chamber provided in the abutting portion to manufacture a hollow molded body , one primary product has a through hole communicating with the filling chamber. It is assumed that the injection nozzle tip for secondary injection of the injection material is abutted against the through hole of the primary product in the abutted state, and the resin material is secondarily injected using the through hole as a sprue. In doing so , the through-hole serving as the sprue is formed by a valve gate pin provided in an injection nozzle for secondary injection .

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