JP3203761B2 - Method for producing synthetic resin frame - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a synthetic resin frame-like body having a hollow frame portion.

[0002]

2. Description of the Related Art As a synthetic resin frame, there is, for example, a radiator grill attached to a front portion of an automobile.
As shown in FIGS. 9 and 10, the hood 8 (hood) covering the front engine room and the trunk room of the automobile is
It is attached to the body 81 via a hood hinge and a lock (not shown) so that it can be opened and closed. The bonnet 8 includes a front opening type and a rear opening type.

As shown in FIG. 9, the front opening type bonnet 8 is of a separate type in which the front end is separated from the radiator grill 9. In this type, the radiator grill 9 is attached and fixed to the body 81 side.

The radiator grille 9, especially of the separate type, is designed to prevent deformation and sink marks.
As shown in FIG. 11, a rib 95 is provided at a substantially central portion on the rear side. Further, the radiator grill 9 has gaps 90 on both sides of the rib 95. Such a radiator grill 9
In manufacturing the mold, a mold 7 shown in FIG. 12 is used. The mold 7 includes a movable mold 71 having a convex portion 710 for forming the above-mentioned gap 90, and a fixed mold 72.
A cavity 73 for molding the radiator grill 9 is provided between the movable die 71 and the fixed die 72. As shown in FIG. 13, the movable mold 71 has a concave portion 712 for forming the rib 95 between the convex portions 710. At the rear of the radiator grill 9, the reinforce is wrapped around to maintain rigidity.

[0005]

However, the above prior art has the following problems. That is, in a separate type in which the hood 8 is separated from the radiator grill 9, as shown in FIG. Therefore, a larger load is applied to the upper part 91 of the radiator grill 9 than in the direction of the arrow. As a result, the upper portion 91 of the radiator grill 9 may be deformed or damaged. However, the above prior art has the following problems. That is, as shown in FIGS.
0,710, the structure becomes complicated. Also, depending on the shape of the molded product, there is the convex portion 710, and the strength is insufficient.
Demolding may be difficult. Further, the deformation of the radiator grill 9 can be prevented to some extent by the formation of the ribs 95, but this alone does not provide sufficient mechanical strength such as rigidity. Further, since the reinforce is provided behind the radiator grill 9, the weight increases accordingly.

Therefore, in order to prevent the radiator grill 9 from being deformed or damaged, the upper part 91 and the lower part 94 are formed.
It is conceivable to improve the rigidity by forming a hollow part in the frame part. As described above, examples of the synthetic resin frame including the lattice portion and the frame portion provided on the outer periphery thereof include the above-described radiator grille and a duct grill provided at an air conditioning duct outlet. Also for these, improvement in rigidity and weight reduction are required. The present invention has been made in view of such conventional problems, and has as its object to provide a method of manufacturing a synthetic resin frame having excellent rigidity, light weight, and easy position control of a hollow forming portion. is there.

[0007]

According to the present invention, a grid portion is formed around a grid portion.
Of a synthetic resin frame having a hollow hollow frame portion
Forming the grid portion, and then forming the grid portion.
Inject resin for the frame around the
Injects pressurized fluid into resin to form hollow in frame
After that, remove the molded product of the synthetic resin frame from the mold
A method for producing a synthetic resin frame .

Examples of the synthetic resin frame include a radiator grill for an automobile, a duct grill used for an air outlet for air conditioning, a defroster, and the like. The frame portion includes, for example, an upper frame, a lower frame, and a connection frame connecting these. As the lattice portion, for example, as shown in the embodiment, there is a mode in which the horizontal bar and the vertical rib are orthogonal to each other in a lattice shape (FIG. 1).

The lattice portion and the frame portion are injection molded using, for example, acrylonitrile butadiene styrene (ABS) resin, polypropylene (PP) resin, polycarbonate (PC) resin, acrylonitrile ethylene propylene diene rubber styrene (AES) resin, or the like. The hollow portion is formed by injecting a pressurized fluid such as a gas such as nitrogen gas or a liquid such as water into the resin upon injection molding.

[0010] The Te is manufacturing how smell of the synthetic resin frame-like body, strike the producing synthetic resin frame-shaped member having a hollow frame portion which is formed around the grating portion, forming the grating part Then, the mold is inverted while holding the grid portion, and the frame resin is injected around the grid portion,
The hollow portion is formed in the frame portion by injecting a pressurized fluid in said frame for resin, then, refers to a molded product of synthetic resin frame-like body how to Eject from the mold (hereinafter, also called two-color molding method ). Another injection molding method is an insert molding method.

In the above-mentioned mold, for example, in a two-color molding machine (FIG. 2), two types of a mold for forming a lattice portion and a mold for forming a frame portion are set. Also, a mold for insert molding is prepared. The two-color molding method is a method named after forming the lattice part first, then reversing the mold to form the frame part, and performing the molding in two (two colors). It is. In the insert molding method,
A lattice part formed in advance is inserted (set) in a mold.

As a method of manufacturing the above synthetic resin frame, a method of manufacturing a synthetic resin frame having a lattice portion and a hollow frame portion formed around the lattice portion includes the steps of: Inject resin to form the grid, then
A method of injecting a frame resin around the lattice portion and injecting a pressurized fluid into the frame resin to form a hollow portion in the frame portion, wherein the gate position for the lattice resin injection is formed. And a method for manufacturing a synthetic resin frame (hereinafter also referred to as a delayed molding method), wherein the position of the frame resin and the position of the gate for injecting the pressurized fluid are different. The delayed molding method is a molding method named because a plurality of gates are provided and the timing of resin and gas injection from the gates is delayed.

[0013]

The radiator grille obtained by the manufacturing method of the present invention has a hollow portion in the frame portion. Therefore, the section modulus of the frame part increases, and the rigidity improves. In addition, the hollow portion is lighter in weight than the solid portion, and can save resin material and the like. The reason for the increase in the section modulus of the frame portion is that the conventional frame portion was an open cross section in the conventional product in which the solid portion was a solid portion, but in the present invention, it becomes a hollow portion and becomes a closed cross section. Therefore, it is considered that the rigidity of the cross section of the frame having the hollow portion is improved.

Therefore, the hollow portion is excellent in rigidity without being deformed or damaged by the load in the vertical direction. Further, the synthetic resin frame is provided by the manufacturing method described above.
It can be produced more. As a result, the pressurized fluid is efficiently and accurately injected into the movable resin that flows or contracts,
Position control of the hollow molded portion is facilitated. Would therefore excellent positional accuracy of the hollow portion of the full record <br/> over arm portion. Also,
Since the mold has a relatively simple structure, it is easy to remove the mold. As described above, according to the present invention, it is possible to provide a method of manufacturing a synthetic resin frame-like body having excellent rigidity, light weight, easy position control of the hollow forming portion, and easy removal from the mold.

[0015]

【Example】

Example 1 A synthetic resin frame according to an example of the present invention will be described with reference to FIG. The synthetic resin frame according to the present embodiment shows a radiator grill for an automobile. The radiator grill has a grid portion 1 and a frame portion 2 formed therearound as shown in FIG. The frame unit 2 includes an upper frame 21, a lower frame 22, and a connection frame 23 connecting these. It should be noted here that the frame portion 2 has hollow portions 210, 220 and 230 in each of the above-mentioned frame portions.

Further, these hollow portions 210, 220, 2
30 is an upper frame 21 and a lower frame 2
2. It is located at a substantially central portion of the connection frame 23. The hollow portions 210, 220 and 230 have a diameter of approximately 5
It has a substantially circular cross section of 7 mm. The hollow portion is formed by injecting a pressurized nitrogen gas as a pressurized fluid into the frame resin after or substantially simultaneously with the injection of the frame resin.

The grating 1 and the frame 2 are made of ABS.
Made of resin. Further, the lattice portion 1 and the frame portion 2 are manufactured by a two-color molding method or a delayed molding method, for example, as described in Example 2 or 3 described later. Note that an insert molding method may be used instead of the delayed molding method.

Next, the function and effect will be described. In the radiator grill of this example, the frame portion 2 has a hollow portion. Therefore, the section modulus of the frame portion 2 increases, and the rigidity improves. Further, this hollow portion is lighter in weight than the solid portion of the conventional product, and saves resin material and the like. The reason for the increase in the section modulus of the frame portion 2 is that the conventional frame portion 2 has a substantially U-shaped open cross-section made up of a solid portion, but in this example, it has a hollow U-shaped cross-section and has a closed cross-section. Become.
Therefore, in the frame portion 2 having the hollow portion, it is considered that the sectional rigidity is improved. Therefore, the hollow portion is excellent in rigidity without being deformed or damaged by the load in the vertical direction.

Embodiment 2 In this embodiment, as shown in FIGS. 2 to 4, the radiator grill according to Embodiment 1 is injection-molded by a two-color molding method. The two-color molding method is a method of injecting using a two-color molding machine 4 as shown in FIG. First, the outline will be described. The lattice portion 1 is formed, and then the molds 43 and 44 are inverted while holding the lattice portion 1, and a frame resin is injected around the lattice portion 1. And with this,
A pressurized nitrogen gas as a pressurized fluid is injected into the frame resin to form hollow portions 210, 220, 230 in the frame portion 2.
Is molded. Thereafter, the molded product of the radiator grill is removed from the mold.

Hereinafter, this will be described in detail. The two-color molding machine 4
A rotating shaft 41, a rotating mold 42 mounted thereon, a lattice forming mold 43, a frame forming mold 44, hoppers 432 and 442 for supplying resin thereto, and a sprue 43.
1,441.

In performing the two-color molding method, as shown in FIGS. 2 and 3, first, the grid portion 1 is injection-molded using a rotary mold 42 and a grid mold 43. Next, FIGS.
As shown in (1), after the rotating shaft portion 41 is turned in the direction of the arrow, ABS resin as a frame resin is injected around the lattice portion 1 using the rotating mold 42 and the frame forming mold 44. The frame part 2 is formed. At this time, as shown in FIG. 4, pressurized nitrogen gas (not shown) is injected into the molten resin from the mold gates 51 and 52.

Since the pressurized nitrogen gas is immediately injected into the ABS resin as a resin for the frame, it is injected when the ABS resin is in a movable state in which it flows or contracts.
Therefore, the pressurized nitrogen gas flows uniformly and quickly through the ABS resin in a state where the resistance due to the resin is small.
As a result, it is possible to obtain a molded product in which the hollow portions 210, 220, and 230 exist only in the frame portion and do not exist in the lattice portion 1.

As a result, the hollow portion 21 is
A radiator grille having zero can be obtained by injection molding intermittently or continuously. Further, the accuracy of position control of the hollow portion 210 is improved. Therefore, according to this example, the radiator grille which is excellent in rigidity and is lightweight, easy to control the position of the hollow forming portion, and easy to remove from the mold can be manufactured with good productivity, and the hollow portion 210 can be easily and accurately positioned. Obtainable.

Embodiment 3 In this embodiment, as shown in FIGS. 5 to 8, the radiator grill according to Embodiment 1 is injection-molded by the main molding method. In this molding method, an ABS resin as a lattice resin 6 is first injected into a mold 5 (FIG. 8) to form the lattice portion 1. Next, an ABS resin as a frame resin is injected around the lattice portion 1, and a pressurized nitrogen gas 62 (FIG. 7) as a pressurized fluid is injected into the frame resin. Hollow parts 210, 220, 23 in each part
0 (FIG. 8).

It should be noted that the position of the gate 51 for injection of the lattice resin (FIG. 5) and the gates 52 and 53 for injection of the frame resin and the pressurized fluid (FIG. 6).
Is different from each other.

Hereinafter, the delayed molding method will be described in detail. In the delayed molding method, first, as shown in FIG. At this time, the resin (not shown) is injected from the gate 51 substantially at the center of the lattice 1. Next, as shown in FIG.
The resin 6 is injected to form the frame 2 around the lattice 1. At this time, the ABS resin 6 is injected from the gate portions 52 and 53 located at the upper and lower central portions of the frame portion forming portion.

Next, as shown in FIG. 7, a pressurized nitrogen gas 62 is injected into the ABS resin 6 from the gates 52 and 53. Thereby, the hollow portion 210 is formed in the frame portion 2.
Can be formed with high positional accuracy. As shown in FIG. 8, a first embodiment having a lattice portion 1 and a hollow frame portion 2 formed around the lattice portion 1 in a mold 5.
To obtain the radiator grill shown in (1).

As shown in FIG. 7, the pressurized nitrogen gas 62 is injected when the ABS resin 6 for the frame resin flows or contracts and is in a movable state. for that reason,
The pressurized nitrogen gas 62 flows uniformly and quickly through the ABS resin 6 when the resistance of the resin is small. As a result, since the lattice portion 1 is formed first, almost no hollow portion is formed. In addition, the hollow portions 210, 220, and 230 are easily formed in any of the upper frame 21, the lower frame 22, and the connection frame 23. As described above, according to this example, the hollow portions 210, 220, 2
It is possible to easily obtain a lightweight radiator grill having excellent positional accuracy and rigidity of 30. Note that an insert molding method may be used instead of the above-described molding method.

[Brief description of the drawings]

FIG. 1 is a front view of a radiator grill as a synthetic resin frame according to a first embodiment.

FIG. 2 is an explanatory view of a two-color molding machine in a second embodiment.

FIG. 3 is a plan view showing a state in which a lattice portion is formed in a mold according to a second embodiment.

FIG. 4 is a plan view showing a state in which a frame portion is molded in a mold according to the second embodiment.

FIG. 5 is a plan view showing a state in a cavity according to a third embodiment.

FIG. 6 is a plan view showing a state in which a resin is injected into a cavity in the third embodiment.

FIG. 7 is a plan view showing a state in which a pressurized fluid is injected into a resin in a third embodiment.

FIG. 8 is a plan view of a mold according to a third embodiment, showing a state in which a hollow portion is formed in a cavity.

FIG. 9 is a perspective view showing a usage state of a conventional radiator grill.

FIG. 10 is a sectional view taken along line BB of FIG. 9;

FIG. 11 is a perspective view showing another mode of a conventional radiator grill.

FIG. 12 is a cross-sectional view of a mold for making another conventional radiator grill.

FIG. 13 is a plan sectional view of the mold of FIG. 12;

[Explanation of symbols]

 1. . . Lattice part, 11. . . Horizontal bar, 110. . . Hollow part, 12. . . Longitudinal rib, 120. . . Hollow part, 2. . . Frame part, 21. . . Upper frame part, 210. . . Hollow part, 22. . . Lower frame, 220. . . Hollow part, 4. . . 4. Two-color molding machine, . . Mold, 50. . . cavity,

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-62-82013 (JP, A) JP-A-64-44228 (JP, A) JP-A-4-327129 (JP, A) JP-A 63-2013 268611 (JP, A) Japanese Utility Model Sho 51-98526 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B29C 45/00-45/84

Claims (2)

(57) [Claims] 1. A method of manufacturing a synthetic resin frame having a lattice portion and a hollow frame portion formed around the lattice portion, wherein the lattice portion is formed, and a frame material is formed around the lattice portion. A synthetic resin characterized by injecting a resin and injecting a pressurized fluid into the frame resin to form a hollow portion in the frame portion, and then removing a molded product of the synthetic resin frame from the mold. A method for producing a frame. 2. In manufacturing a synthetic resin frame having a lattice portion and a hollow frame portion formed around the lattice portion, a lattice resin is injected into a mold to form the lattice portion. A method of injecting a frame resin around the lattice portion and injecting a pressurized fluid into the frame resin to form a hollow portion in the frame portion, wherein the gate position for the lattice resin injection is formed. And a position of the frame resin and a gate position for injecting a pressurized fluid are different from each other.