JPH07314542A - Production of hollow body with pipe - Google Patents

Abstract

PURPOSE:To obtain a method for producing a hollow body with pipe in which a pipe, communicating positively, can be molded integrally by blow-molding. CONSTITUTION:A hollow body 12 equipped integrally with a pipe part 11 communicating with the hollow body is produced through blow-molding. A parison 7 is disposed between a pair of split dies 1 for blow-molding so that burrs 8 are formed on the outside of a cavity 4 for forming the pipe. Pressure fluid is fed into the parison at the pipe part 11 at an appropriate time during the closing step thus completing the blow-molding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a hollow body with a pipe such as a tank with a spout pipe or a duct with a branch pipe by blow molding.

[0002]

2. Description of the Related Art Conventionally, as a hollow body with a pipe of this type, for example, there is a reserve tank of an automobile.
Japanese Patent Publication No. 24761 describes a method of integrally manufacturing a tank body of a reserve tank and a pipe portion, which is a pipe hose connection portion protruding from the tank body, by blow molding.

According to the method for manufacturing a reserve tank described in the above publication, the tank body, the pipe portion, and the cavity of the air escape space are formed in series in the mold, and the air is blown into the parison to form the tank. Prevents buildup of the pipe part by sending air from the main body through the path of the pipe part and the air bleeding space to complete blow molding and finally blowing air into the air escape space Is proposed.

[0004]

However, it was confirmed by the study of the present inventor that the above-mentioned conventional technique has the following problems.

(1) When the air is blown into the air escape space, the air flow is stopped. Since the expansion and deformation of the parison by the air is actually instantaneous, practically no air flows in the pipe, and the meat is not formed at the stage of forming the pipe before the air escape space is finally formed. Occurrence of accumulation is inevitable.

(2) The parison in the cavity of the tank body of the mold expands by blowing air, and the tank body, the pipe portion, and the air escape space are formed in this order, but the cavity of the pipe portion is the tank. Since it is extremely narrow as compared with the cavity of the main body, plastic deformation of the resin stops near the base end of the pipe portion, and defective molding of parison occurs.

As described above, according to the above-mentioned conventional technique, the main body of the tank and the pipe portion cannot be substantially integrally blow-molded, and according to the conventional blow-molding technique, the inside of the closed mold is closed. Therefore, since the air was blown into the parison, it was impossible to stably mold the thin and long pipe part integrally with the main body of the molded product. The present invention has been made by focusing on the fact that disposing a parison before blow molding in a portion accurately contributes to solving the conventional problems.

Therefore, the present invention is a method of blow molding a hollow body having an integral pipe communicating with the body of a hollow body such as a tank, even if the pipe has a small diameter and a relatively long length. An object of the present invention is to provide a method for producing a hollow body with a pipe, which can integrally form a pipe which is surely communicated by blow molding.

[0009]

In order to achieve the above object, a method of manufacturing a hollow body with a pipe according to the present invention is a blow molding of a hollow body having an integral pipe portion communicating with the main body of the hollow body. A method of manufacturing a pipe part between the split molds in which the main body of the hollow body and the molding cavity of the pipe part are in communication with each other and the molding cavity of the pipe part can be communicated outside the mold. The parison is arranged so that the parison covers the cavity, and then the pressure fluid is circulated from the inside of the parison of the pipe portion toward the outside of the mold at the time of mold clamping, and then the blow molding is completed.

Further, in the method for producing a hollow body with a pipe according to the present invention, in the above method, a pressure fluid is circulated inside the parison of the pipe portion, and a passage communicating with the pipe portion is formed when the pipe portion is appropriately cooled and hardened. It is closed to complete blow molding.

[0011]

According to the method of manufacturing the hollow body with a pipe of the present invention, the main body of the hollow body and the molding cavity of the pipe portion are in communication with each other, and the molding cavity of the pipe portion can be communicated with the outside of the mold. Since the parison is arranged so that the parison covers the molding cavity of the pipe between the split-type blow molding dies and blow molding is performed, the parison forming the pipe in the pipe molding cavity during the mold clamping process should follow the cavity. Held in. Then, since the pressure fluid is circulated from the inside of the parison of the main body of the hollow body to the inside of the parison of the pipe portion during mold clamping, blow molding can be completed without causing resin clogging in the pipe portion.

In the present invention, if the pressure fluid is circulated inside the parison of the pipe portion and the blow molding is completed by closing the pipe portion when the pipe portion is appropriately cooled and hardened, the pipe portion is clogged with resin. In addition, there is no leakage of the pressure fluid during blow molding of the hollow body, and the blow pressure can be effectively increased.

[0013]

1 to 3 show blow molding modes of a hollow body with a pipe according to the present invention in the order of molding steps.
Reference numerals 1 and 2 are split-type blow molding dies. This blow molding die constitutes a pair of split molds composed of one blow molding die 1 and the other blow molding die 2. Reference numeral 3 is a hollow body main body molding cavity, 4 is a pipe molding cavity, and the pipe molding cavity 4 includes:
Further, a passage forming cavity 5 communicating with the outside is provided in series. 6 is a mouth part forming cavity.

In blow molding of a hollow body with a pipe, as shown in FIG. 1, a parison 7 is extruded from an extrusion head (not shown) to divide the blow molding die 1 on one side and the blow molding die on the other side. A parison 7 is arranged between the molds 2 of the type so as to form a burr 8 outside the pipe molding cavity 4 and the passage molding cavity 5.

Next, as shown in FIG. 2 from the state of FIG. 1, the blow molding dies 1 and 2 are clamped, and in the course of the clamping, the mouth portion forming cavity 6 has a mouth portion having a blow nozzle 9. The regulator 7 is inserted, and the pressure fluid is introduced from the blow nozzle 9 of the mouth regulator 10 into the parison 7 shortly before the completion of the mold clamping until the completion of the mold clamping to blow the parison 7. At the same time, the pressure fluid is circulated from the inside of the parison formed along the pipe molding cavity 4 and the passage molding cavity 5 toward the outside of the mold. In this way, the pressure fluid is circulated inside the parison of the pipe portion 11 at the time of mold clamping, so that the pipe portion 11
The internal shape of the pipe is adjusted and the resin is not clogged, and the pipe portion 11 is formed in a communicating shape.

Next, the resin of the pipe portion 11 (parison)
3 is appropriately cooled and hardened, the passage forming cavity 5 is closed as shown in FIG. 3, and the pressure fluid is further inserted from the blow nozzle 9 of the mouth regulator 10 to complete the blow molding. By closing the passage communicating with the pipe forming cavity 4, it is possible to prevent leakage of the pressure fluid and effectively increase the blow pressure. The passage is closed, for example, by pressing the parison with a slide member (not shown) provided in the blow molding die 1 so as to press the parison. In addition, without closing the passage,
The pressure fluid may continue to flow inside the parison of the pipe portion 11 during blow molding, but in this case, the amount of the pressure fluid introduced for blow molding must be increased by that amount, but on the other hand, the pressure fluid of the pipe portion 11 must be increased. The molding state becomes good and cooling is promoted, and the molding cycle can be shortened.

FIG. 4 shows a hollow body with a pipe 12 manufactured by the manufacturing method according to the present invention. As shown in FIG. 3, since the passage portion 13 is attached to the pipe portion 11 of the blow-molded hollow body 12, the passage portion 13 of the pipe portion 11 of the hollow body 12 taken out of the blow molding die 1. Is cut to form the pipe portion 11 for connecting the connection hose 14.

As described above, according to the manufacturing method of the present invention shown as the embodiment, the parison 7 is formed between the blow molding dies 1 and 2 so as to form the burr 8 outside the portion of the pipe molding cavity 4. Since they are arranged and blow-molded, the parison forming the pipe portion 8 in the pipe-molding cavity 4 portion of the blow-molding dies 1 and 2 is held along the pipe-molding cavity 4 in the mold clamping process. Then, since the pressure fluid is circulated inside the parison of the pipe portion 11 at an appropriate time during the mold clamping process, blow molding can be completed without causing resin clogging in the molded pipe portion 11.

[0019]

According to the present invention, even in the method of blow-molding a hollow body having an integral pipe communicating with the main body of a hollow body such as a tank, the pipe which is surely communicated is integrally molded. The effect that can be obtained is obtained.

[Brief description of drawings]

FIG. 1 is a front view showing a mode in which a parison is arranged between blow molding dies, while omitting the other of the pair of split dies.

FIG. 2 is a front view showing a mode in which a pressure fluid is introduced into the parison after the mold is clamped, while omitting the other of the pair of split molds.

FIG. 3 is a front view showing the blow molding completed state from the state of FIG. 2 with the other of the pair of split molds omitted.

FIG. 4 is an enlarged sectional view taken along line AA of FIG.

FIG. 5 is a front view of a hollow body with a pipe manufactured by a manufacturing method according to the present invention.

[Explanation of symbols]

 1 Blow Molding Die 2 Other Blow Molding Die 3 Hollow Body Main Body Molding Cavity 4 Pipe Molding Cavity 5 Passage Molding Cavity 6 Mouth Molding Cavity 7 Paris 8 Burr 9 Blow Nozzle 10 Mouth Regulator 11 Pipe 12 Hollow body with pipe 13 Passage 14 Connection hose

Claims (2)

[Claims] 1. A method for producing a hollow body by blow molding, the hollow body having an integral pipe section communicating with the main body of the hollow body, the main body of the hollow body and the molding cavity of the pipe section being in communication with each other. A parison is placed between the split molds that are configured so that the molding cavity of the pipe can be communicated with the outside of the mold, and then the parison covers the molding cavity of the pipe. A method for producing a hollow body with a pipe, characterized in that blow molding is completed after the material is further distributed to the outside of the mold. 2. The blow molding is completed by causing a pressure fluid to flow inside the parison of the pipe portion and closing the passage communicating with the pipe portion when the pipe portion is appropriately cooled and hardened. For manufacturing a hollow body with a pipe.