JPH06297554A - Molding method for hollow body - Google Patents

Abstract

PURPOSE:To form a mounting hole orthogonally to the wall thickness direction of a bracket on a mounting bracket in the blow molding of hollow body in which no flash remains in a mold at the time of blow molding, a mounting hole, beautiful and of high accuracy, can be formed and the mounting bracket using a blow molding die and a mold split face not crossing the mold clamping direction is provided integrally. CONSTITUTION:A mounting bracket 5 with a mounting hole recessed section 22 is compression molded by mold clamping in the state of protruding a core mold 21 into a molding recess 16 of the mounting bracket positioned on the mold split face of a blow molding die 8. Then the core mold 21 is moved back further than the molding recess 16 in the direction different from the mold clamping direction, and then the blow molding die 8 is opened to release a molded product, and a flash on the mounting hole recessed section 22 is cut and removed along the face of the mounting bracket 5 to form a mounting hole opened on the mounting bracket 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hollow body made of synthetic resin such as various tanks and ducts, which is integrally provided with a mounting bracket having a mounting hole, and is molded by blow molding of thermoplastic synthetic resin. The present invention relates to a method for forming a hollow body.

[0002]

2. Description of the Related Art Conventionally, in the manufacture of hollow bodies such as tanks and brackets that are integrally provided with a mounting bracket,
As a secondary process after blow molding, a hole or hole is drilled by a drill or press on a mounting bracket that has no hole and is formed by blow molding. In addition, the actual development Sho 60-837
As described in Japanese Patent No. 21, a hollow body made of synthetic resin such as various tanks and ducts, which is integrally provided with a bracket having a mounting hole, is formed by blow molding of thermoplastic synthetic resin. A method for molding a hollow body has also been conventionally known.

[0003]

In manufacturing a hollow body such as a tank or a bracket integrally provided with a mounting bracket, a method of drilling a hole in the mounting bracket by drilling or pressing easily causes positional deviation of the hole. There is a drawback in that the drilling direction tends to be a bent hole that is not orthogonal to the thickness direction of the mounting bracket, resulting in low processing accuracy. Further, as disclosed in Japanese Utility Model Laid-Open No. 60-83721, in a method of integrally molding a bracket having a mounting hole at the time of blow molding of a hollow body, after compressing the resin of the portion serving as the mounting bracket, Since the pin forming the mounting hole is advanced to open the mounting hole and separate the burr, an irregular thin resin film remains in the formed mounting hole, and not only post-processing to remove this is required, There is a problem that a part of the resin moved by the advance of the pin remains in the mold, which hinders the subsequent molding.

The present invention is intended to solve the above problems in the method of molding a hollow body in which a hollow body integrally provided with a mounting bracket having a mounting hole is molded by blow molding of a thermoplastic synthetic resin. Therefore, the mounting hole recess should be formed in the mounting bracket that is molded during blow molding of the hollow body, with the core mold that forms the mounting hole recess when clamping the blow mold protruding from the molding recess of the mounting bracket. By this, the burr of the resin for molding the mounting hole during blow molding does not remain in the mold, and the burr of the mounting hole recess is removed along the surface of the mounting bracket in the secondary processing after blow molding. As a result, an irregular thin resin film does not remain around the mounting hole, and a beautiful and highly accurate mounting hole can be formed.In particular, the parting surface is orthogonal to the mold clamping direction. In blow molding of a hollow body integrally having a mounting bracket using a blow molding die, there is provided a method of molding a hollow body capable of forming a mounting hole in the mounting bracket that is orthogonal to the thickness direction thereof. To aim.

[0005]

In order to achieve the above object, in the method of molding a hollow body according to the present invention, a hollow body integrally provided with a mounting bracket having a mounting hole is molded by blow molding of a thermoplastic synthetic resin. In the hollow body molding method described above, the blow molding die for the hollow body is a pair of split molds, and the mold splitting surface is not orthogonal to the mold clamping direction, and is positioned on the mold splitting surface of the blow molding die. Provided in the molding recess of the mounting bracket, which is provided with a projecting / retracting core mold for molding the mounting hole recess of the mounting bracket, and clamping the core mold in a state of protruding from the molding recess, the mounting bracket having the mounting hole recess After compression molding, then retract the core mold from the molding recess in a direction different from the mold clamping direction, open the blow molding mold and take out the molded product, and the mounting hole recessed by the core mold of the molded product It was excised along the burrs on the surface of the mounting bracket, and forms an open mounting hole in the mounting bracket.

[0006]

According to the hollow body molding method of the present invention, the core die for molding the mounting hole concave portion of the mounting bracket is formed in the molding recess of the mounting bracket positioned on the split surface of the blow molding die for the hollow body. Since the mounting bracket having the mounting hole concave portion is compression-molded by being clamped in the protruding state, the mounting hole concave portion in which the resin burr is not separated is formed in the mounting bracket during blow molding. Therefore, no burrs for molding the mounting hole recesses remain in the blow molding die. Then, as a secondary process after blow molding, the burr of the mounting hole recess is cut along the surface of the mounting bracket to form a mounting hole opened in the mounting bracket, so that the resin forms a thin film around the mounting hole. A beautiful and highly accurate mounting hole is formed without remaining.

The core mold provided in the molding recess of the mounting bracket positioned on the mold splitting surface of the blow molding mold has a mounting hole recessed by being clamped in a state of protruding in a direction orthogonal to the molding recess. Since the mounting bracket can be compression molded, in blow molding of a hollow body that integrally has a mounting bracket that uses a blow molding die whose mold splitting surface is not orthogonal to the mold clamping direction, make sure that the mounting bracket is aligned with the thickness direction. Orthogonal mounting holes can be formed.

[0008]

Embodiments of the present invention will be described with reference to the drawings. Figure 1
And FIG. 3 illustrates an automobile window cleaning liquid tank as a hollow body formed by the method according to the present invention. In FIGS. 1 and 3, reference numeral 1 denotes a cleaning liquid tank, and this tank 1 is formed by blow molding of a thermoplastic synthetic resin as described later. Reference numeral 2 is a cleaning liquid injection port, 3 is a mounting recess of a cleaning liquid pump, 4 is a cleaning liquid delivery port, and the cleaning liquid delivery port 4 is connected to a cleaning liquid pump (not shown). A thin mounting bracket 5 is integrally formed on the upper wall of the tank 1, and the mounting bracket 5 has an elongated hole-shaped mounting hole 6. 7 is a parting line, and this parting line 7 corresponds to a parting surface which is a mating surface of a blow molding die composed of a pair of split dies, and the injection port portion 2 and the mounting bracket 5 are on the parting line 7. Is located in. The illustrated tank 1 is in the shape of a rectangular tube, and the mold dividing line 7 is formed in a direction connecting substantially diagonal ridge lines.

The tank 1 shown in FIG. 1 and FIG.
Blow molding is performed in the manner shown in FIGS. In FIGS. 4 to 6, reference numeral 8 is a blow molding die including a pair of split molds 9 and 10. In the blow molding die 8, the mold splitting surfaces 11 and 12 of the pair of split dies 9 and 10 are not orthogonal to the mold clamping direction A. The pair of split molds 9 and 10 have cavities 13 and 13 for molding the tank 1.
14 is a molding cavity of the injection port portion 2, 15 is a molding convex portion of the mounting concave portion 3 of the cleaning liquid pump, and the molding cavity 14 of the injection port portion 2 is the molding surface 11 of the pair of split molds 9, 10.
It is located so that it divides into 11. Reference numeral 16 denotes a molding recess of the mounting bracket 5. The molding recess 16 is located on the mold dividing surface 12 of the split mold 10. The split mold 9 has a burr receiving recess 17 corresponding to the molding recess 16. Are formed. 18 is a parison.

The molding recess 16 of the mounting bracket 5 is surrounded by a projection 19 that defines the periphery of the mounting bracket 5 and forms a flat surface. The burr receiving portion 2 is provided outside the projection 19.
0 is provided. 21 is a core type. The core mold 21 forms a mounting hole recess 22 for providing the mounting hole 6 in the mounting bracket 5, and the molding recess 16 is formed.
It is slidably supported so as to project from or retract from, and can be projected and retracted by the hydraulic cylinder 23. The corner 24 between the front end surface and the peripheral surface of the core mold 21 is formed into a curved surface or a flat surface so that the boundary portion 25 formed by the front peripheral end of the burr receiving recess 17 does not interfere with the mold clamping.

Next, the mounting bracket 5 having the mounting hole 6
A molding mode of the tank 1 integrally provided with will be described with reference to FIGS. 4 to 6. As shown in FIG. 4, the parison 18 is arranged between the split molds 9 and 10, and the split molds 9 and 10 are clamped to perform blow molding. When the split molds 9 and 10 are clamped, the core mold 23 is held in a state of being projected from the molding recess 16 of the mounting bracket 5, as shown in FIGS. 5 and 6.

As shown in FIGS. 5 and 6, as the mold clamping of the split molds 9 and 10 progresses, the part of the parison 18 surrounded by the projection 19 is compressed and thinned by the molding recess 16 to make the tank. The mounting bracket 5 that is integral with 1 is molded, and the core die 21 that projects from the molding recess 16 forms the mounting hole recess 22 that becomes the mounting hole 6. After the blow molding, the core mold 21 is retracted from the molding recess 16, the split molds 9 and 10 are opened, and the molded tank 1 is taken out. Then, as a secondary processing, the mounting hole recess 2
The closed burr 2 is cut along the surface of the mounting bracket 5 with a cutter or the like to form a mounting hole 6 opened in the mounting bracket 5.

As described above, the core die 21 is clamped in the molding recess 16 of the mounting bracket 5 located on the mold splitting surfaces 11 and 12 of the blow molding die 8 of the tank 1 and the mounting hole is secured. Since the mounting bracket 5 having the recess 22 is compression-molded, the mounting hole recess 22 is formed in the mounting bracket 5 in such a manner that resin burrs do not separate during blow molding. Therefore, the blow molding die 8 has a mounting hole recess 22.
Burr for molding is not left. Then, as secondary processing after blow molding, the burr of the mounting hole recess 27 is cut along the surface of the mounting bracket 5 to form the mounting hole 6 opening in the mounting bracket 5, so that the mounting hole 6 is formed around the mounting hole 6. The resin does not remain in the form of a thin film, and a beautiful and highly accurate mounting hole 6 is formed.

Further, the mold splitting surface 11 of the blow molding die 8,
The core die 21 provided in the molding recess 16 of the mounting bracket 5 located at 12 is clamped in a state of protruding in a direction orthogonal to the surface of the molding recess 16 to mount the mounting bracket 5 having the mounting hole recess 22. Molding surface 1 because compression molding
Even when the blow molding die 8 in which 1 and 12 are not orthogonal to the mold clamping direction is used, the mounting bracket 5 should be provided with the mounting hole 6 that is orthogonal to the thickness direction thereof, as shown in FIG. You can It should be noted that FIG. 2 illustrates a tank 1 formed by using a blow molding die whose molding surface is orthogonal to the mold clamping direction for comparison with that of FIG. 3 according to the present invention. In the blow molding method using the blow molding die whose surface is orthogonal to the mold clamping direction, it is clear that the mounting hole 6 cannot be formed in the mounting bracket 5 as shown in FIG. Is. As described above, according to the present invention, by using the blow molding die 8 in which the mold splitting surfaces 11 and 12 are not orthogonal to the mold clamping direction, the mounting holes 6 are formed in the mounting bracket 5 correctly orthogonal to the thickness direction thereof. Therefore, the mounting bracket 5 can be provided at an arbitrary position according to the mounting conditions of the tank 1.

The tank shown as the embodiment of the present invention is made of blow-moldable thermoplastic synthetic resin such as polyethylene, polypropylene, polycarbonate, polystyrene and polyamide.

[0016]

According to the present invention, a mounting bracket molded at the time of blow molding of a hollow body with a core mold forming a recess for a mounting hole protruding from the molding recess of the mounting bracket when the blow mold is clamped. By forming the mounting hole recess in the mold, the burr of the resin for molding the mounting hole does not remain in the mold during blow molding, and the burr of the mounting hole recess is mounted in the secondary processing after blow molding. By removing along the surface of the bracket, an irregular thin resin film does not remain around the mounting hole, and a beautiful and highly accurate mounting hole can be formed. In blow molding of a hollow body that integrally has a mounting bracket that uses a blow molding die that is not orthogonal to the direction, it is possible to form a mounting hole in the mounting bracket that is orthogonal to the wall thickness direction. It is obtained.

[Brief description of drawings]

FIG. 1 is an overall perspective view of a tank formed by a method according to the present invention.

FIG. 2 is a plan view of another tank shown as a comparative example for explaining the characteristics of the tank molded by the method according to the present invention.

FIG. 3 is a plan view of a tank formed by the method according to the present invention.

FIG. 4 is a partially cutaway plan view showing an aspect before mold clamping of blow molding for explaining the method according to the present invention.

FIG. 5 is an enlarged cross-sectional view showing a mode immediately before mold clamping of blow molding for explaining the method according to the present invention.

FIG. 5 is an enlarged cross-sectional view showing an aspect at the time of completion of mold clamping of blow molding for explaining the method according to the present invention.

[Explanation of symbols]

 1 Tank 2 Injection Port 5 Bracket 6 Mounting Hole 7 Mold Split Line 8 Blow Molding Mold 9,10 Split Mold 11,12 Mold Splitting Surface 13,13 Cavity 16 Mounting Bracket Molding Recess 17 Burr Bearing Recess 18 Paris 19 Projection 21 core type 22 mounting hole recess

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] December 17, 1993

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

FIG. 1 is an overall perspective view of a tank formed by a method according to the present invention.

FIG. 2 is a plan view of another tank shown as a comparative example for explaining the characteristics of the tank molded by the method according to the present invention.

FIG. 3 is a plan view of a tank formed by the method according to the present invention.

FIG. 4 is a partially cutaway plan view showing an aspect before mold clamping of blow molding for explaining the method according to the present invention.

FIG. 5 is an enlarged cross-sectional view showing a mode immediately before mold clamping of blow molding for explaining the method according to the present invention.

FIG. 6 is an enlarged cross-sectional view showing an aspect at the time of completion of mold clamping of blow molding for explaining the method according to the present invention.

[Explanation of symbols] 1 Tank 2 Injection port 5 Bracket 6 Mounting hole 7 Mold dividing line 8 Blow molding mold 9,10 Dividing mold 11,12 Mold dividing surface 13,13 Cavity 16 Mounting bracket molding recess 17 Burr receiving recess 18 Paris 19 Projection 21 Core Type 22 Mounting Hole Recess

Claims (1)

[Claims] 1. A hollow body molding method for molding a hollow body integrally provided with a mounting bracket having a mounting hole by blow molding of a thermoplastic synthetic resin, wherein the blow molding die for the hollow body is a pair of split molds. Use a mold splitting surface that is not orthogonal to the mold clamping direction, and form a recess in the mounting hole of the mounting bracket in the molding recess of the mounting bracket located on the mold splitting surface of the blow molding die. A core mold is provided, and the core mold is clamped with the core mold protruding from the molding recess to compression-mold a mounting bracket having a mounting hole recess, and then the core mold is retracted from the molding recess in a direction different from the mold clamping direction. After that, open the blow molding die, take out the molded product, cut the burr in the recess of the mounting hole formed by the core mold of the molded product along the surface of the mounting bracket, and open it in the mounting bracket. Method of forming a hollow body and forming a Tsukeana.