JP3053733B2 - Method for manufacturing box having hollow part - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a method for manufacturing a box having a hollow portion by joining a pair of halves.

[0002]

2. Description of the Related Art As a box having a hollow portion, for example, as shown in FIG. 1, it has been proposed to use a compact box having a hollow passage formed therein.
A die slide injection (DSI) method is employed for forming such a box, and the upper half 1 and the lower half 2 are separately formed in a first forming step as shown in FIG.
In the step, the upper mold 10 containing the upper half body 1 and the lower mold 20 containing the lower half body 2 are abutted, and in the third step, the outer cavities C6 to C5 surrounded by the outer joint wall W3 and the mold wall are formed. The secondary resin is injected from the runner through the gate G to rotate the resin flow, and at the same time, is guided to the cavities C1 to C4 surrounded by the inner joining walls W1 and W2 to form a pair of the half bodies 1
And 2 have been proposed.

[0003]

In such a method, in the third step, the secondary resin to be injection-molded is provided with the outer joint wall W3.
To the outer peripheral cavity C5 on the opposite side through the cavity C6 on the gate side surrounded by the mold wall and the cavities C1 to C4 surrounded by the inner joint walls W1 and W2. It needs to be injected at a considerable injection pressure for C6. Therefore, even when the outer joint wall W3 is abutted in the form of fitting, if the injection pressure from the gate G is directly received by the outer joint wall W3, it is found that there is a possibility that resin leakage may occur from the butted portion. Was. Therefore, the present invention relates to manufacturing a box having a hollow portion by joining a pair of half bodies,
It is an object of the present invention to provide a method of manufacturing a box body that does not leak resin even when the injection pressure is increased and is easy to mold.

[0004]

The present invention solves the above-mentioned problem by dividing the resin injected from the gate G before reaching the outer joining wall W3 and guiding the resin in the necessary extending direction of the outer joining wall W3. A pair of halves is formed of primary resin, and the pair of halves are joined by an outer joining wall surrounding the pair of halves, and the outer joining wall and the mold wall are formed. Injecting a secondary resin into a flow path surrounded by a circle and joining a pair of halves to produce a box having a hollow portion, outer joining walls of the pair of halves in which the secondary resin is butted. Is guided obliquely from a position perpendicular to the longitudinal direction, and guided in a longitudinal direction around a pair of half bodies formed by the outer joint wall and the mold wall. When the hollow portion is a bent passage,
A pair of halves are butted by an outer joining wall surrounding the periphery and an inner joining wall extending inward from the outer joining wall, and a secondary resin is formed in a flow path surrounded by the outer joining wall, the mold wall, and the inner joining wall. To form a box having a bent passage formed by being surrounded by the joining wall inside the pair of halves, and injecting the secondary resin to the outside of the pair of halves. It is guided obliquely from a vertical position with respect to the joining wall, and guided to a flow path surrounded by the inside joining walls in the longitudinal direction around the pair of halves formed by the outer joining wall and the mold wall. Features.

[0005]

According to the present invention, the resin to be supplied to the joining portion of the pair of halves is not supplied from the gate G to the cavity serving as the joining portion from the vertical direction but is supplied obliquely. Injection pressure does not act on the butted joint wall,
No resin leakage occurs. In addition, when the resin is supplied obliquely to the outer joint wall, the resin flows easily along the longitudinal direction of the outer joint wall, and even if the injection pressure is increased, it does not cause resin leakage. As a result, the joining force can be improved. In order to guide the flow of the joining resin, a flow path control member facing the injection gate and diverting the resin flow from the injection gate to the outer joining wall is formed in a mold or is formed of a primary resin. It can be provided by molding simultaneously with molding of one of the pair of half bodies. In particular, the flow path control member has a substantially trapezoidal horizontal cross-section with the gate G side as the upper side and the outer joining wall side as the bottom side. The resin pressure from the gate G is received at the upper side of the member, and the trapezoidal oblique side of the member is used. It is preferable that the guide is configured to be guided obliquely with respect to the outer joint wall.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to specific examples shown in the accompanying drawings. In the present invention, as shown in FIG. 6, after the upper half body 1 and the lower half body 2 are separately formed in the first forming step (A), the upper half body 1 is formed in the second step (B). The upper mold 10 accommodating the lower mold half and the lower mold 20 accommodating the lower half body 2 are abutted with each other, and in a third step (C), the gate G from the runner to the outer peripheral cavities C6 to C5 surrounded by the outer joint wall W3 and the mold wall. The secondary resin is injected through the inner wall to rotate the resin flow, and at the same time, the cavities C1 to C2 surrounded by the inner joining walls W1 and W2.
It is guided to C4 to join the pair of half bodies 1 and 2 together.

FIG. 1 is a plan view showing a state in which an upper half of a box B formed by joining a pair of halves is cut horizontally. In the present invention, the lower half 2 is formed in the first forming step. Trapezoidal flow control member 3 with a horizontal cross section outside the outer joining wall W3
Is integrally molded. As shown in FIG. 2, the control member 3 causes the lower half to protrude into the lower mold 20, and the upper half abuts the upper half body 1 and the lower half body 2 to form an injection flow path from the runner to the gate. And guides the secondary resin obliquely from a vertical position to the outer joining wall of the pair of butted halves as shown by the arrow in FIG. It is designed to be guided in a longitudinal direction around a pair of halves formed and a flow path surrounded by inner joint walls. Specifically, it has a substantially trapezoidal horizontal cross section with the gate G side as the upper side and the outer joining wall side as the bottom side. The resin pressure from the gate G is received at the upper side of the member, and the trapezoidal oblique side of the member forms the outer joining wall. Are guided in an oblique direction. In addition, P1 to P4 indicate bent passages, and connect through holes H formed in the bent passages.

After molding, as shown in FIG. 3, the injection gate portion 2G is cut off from the box B having the bent passage. FIG. 4 is a cross-sectional view of the gate portion 2G taken along the line -A.
It is the perspective view seen from the direction.

In the above embodiment, the control member 3 is provided in a part of the lower half body 2 in the first molding step. As shown in FIG. May be provided as projections 21 projecting in a substantially trapezoidal shape in a horizontal cross section in the injection flow path leading to. Otherwise, the same members are denoted by the same reference numerals and description thereof is omitted.

[Brief description of the drawings]

FIG. 1 is a cross-sectional plan view showing a state in which an upper half of a box having a bent passage formed by a method of the present invention is cut off.

FIG. 2 is a cross-sectional view of a gate position in a method employed in the first embodiment of the present invention.

FIG. 3 is a perspective view showing a state where a gate portion is cut from a box formed by the method of the present invention.

4 is a perspective view of a section of the cut gate portion shown in FIG.

FIG. 5 is a cross-sectional view of a gate position in a method employed in a second embodiment of the present invention.

FIG. 6 is a process chart showing a molding process of a DSI method employed in the method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Upper half body 2 ... Lower half body 3 ... Control member 10 ... Upper mold 20 ... Lower mold 21 ... Projection

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-7-195421 (JP, A) JP-A-4-270615 (JP, A) JP-A-4-279318 (JP, A) JP-A-4-199 279317 (JP, A) JP-A-6-170953 (JP, A) JP-A-64-18627 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B29C 45/14 B29C 45 / 26-45/44 B29C 65/70

Claims (5)

(57) [Claims] 1. A pair of halves are formed of a primary resin, and the halves are abutted by an outer joining wall surrounding the halves, and a pair of halves are formed in a flow path surrounded by the outer joining wall and a mold wall. Injecting the secondary resin and joining the pair of halves to produce a box having a hollow portion, the secondary resin is positioned perpendicular to the longitudinal direction of the outer joining wall of the pair of halves abutted against each other. From the diagonal direction,
A method of manufacturing a box having a hollow portion, wherein the box is guided to a flow path in a longitudinal direction around a pair of half bodies formed by the outer joining wall and the mold wall. 2. The method according to claim 1, wherein said hollow portion is a bent passage. 3. A flow path control member which faces the injection gate of the bonding resin and divides the resin flow from the injection gate to the outer bonding wall is formed in a mold.
The manufacturing method as described. 4. A flow path control member which faces the injection gate of the bonding resin and divides the resin flow from the injection gate to the outer bonding wall is formed simultaneously with the primary resin into one of a pair of half bodies. The method according to claim 1. 5. The method according to claim 1, wherein the flow path control member has a gate G side on an upper side.
It has a substantially trapezoidal shape with a horizontal section with the outer joint wall side as the base.
The method according to claim 3 or 4, wherein the resin pressure from the gate (G) is received by an upper side of the member, and the trapezoidal oblique side of the member guides the resin obliquely with respect to the outer joint wall.