JP2696297B2 - Molding method of hollow product consisting of three pieces and mold device therefor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention forms a pair of semi-hollow bodies and an intermediate body interposed therebetween by primary molding, and joins these joints by secondary molding to form a hollow. The present invention relates to a method for forming a three-piece hollow body product for obtaining a body product, and a mold apparatus used for carrying out the method.

[0002]

2. Description of the Related Art As a method for producing a synthetic resin hollow article, a method using an injection molding machine or the like is known. In the case of manufacturing a hollow body product by an injection molding machine, the hollow body product is formed as a half semi-hollow body or a divided body in the primary formation, the divided surfaces are abutted in the secondary formation, and the abutted portion is determined. Heating or welding 1
Manufactures hollow body products. According to the manufacturing method using this injection molding machine, a completely sealed hollow product can be produced, a hollow product having a uniform thickness can be produced, and a complicated shape can be dealt with. However, the present applicant has further improved the above-mentioned production method and provided a method for producing a hollow product suitable for mass production according to Japanese Patent Publication No. 2-38377.

In recent years, the use of plastics has been expanded, and, for example, a part of an intake manifold of an internal combustion engine has been molded from plastics by taking advantage of its characteristics. More specifically, the intake manifold of an automobile is used to guide a mixture for combustion from a carburetor to an engine cylinder, and is also called an intake manifold because a pipe line branches off like a branch. It was integrally formed from a casting. However, the casting is heavy, the weight of the vehicle increases, and the fuel efficiency deteriorates.
More recently, the body has been formed from aluminum and the cover has been molded from lighter weight plastic. As described above, the intake manifold formed by dividing the main body portion made of aluminum or its alloy and the cover portion made of plastic into a separate body is integrally tightened with bolts and nuts via the O-ring at the peripheral edge thereof. I have.

[0004]

Problems to be Solved by the Invention
According to the invention of No. 377, a hollow body product is obtained by sliding or rotating one mold with respect to the other mold in the secondary molding, butting a pair of divided bodies, and injecting a molten resin. Therefore, there is an advantage that each process can be automated and a hollow body product can be mass-produced.
Further, since the pair of divided bodies are formed by injection molding, it has a feature that a hollow body product having a complicated shape can be manufactured.
As described above, although having many advantages, a three-piece hollow body such as the intake manifold of an internal combustion engine as described above cannot be manufactured. Also, it is not suitable as a method for manufacturing a large / medium tank, such as a kerosene tank, which is required to have a strength and requires a stay or a pillar inside. The present invention has been proposed to improve the above-described problems, and is not limited thereto. For example, an intake manifold of an internal combustion engine, such as a large and medium-sized tank where internal strength is required. An object of the present invention is to provide a method for forming a three-piece hollow body suitable for manufacturing a relatively large hollow body product, and a mold apparatus used for performing the forming method.

[0005]

According to the present invention, in order to achieve the above object, the invention according to claim 1 is provided between a fixed mold, a movable mold and these molds. Using a slide mold, a pair of semi-hollow bodies, with their joints facing each other at a first position of the mold, the intermediate interposed between the semi-hollow bodies, The mold is formed with its joints located on both sides at a second position of the mold, and then the slide mold is moved from its second position to a first position of the fixed or movable mold. The semi-hollow body and the intermediate body are slid to each other to hold the joints thereof in contact with each other, and a molten resin is injected into these joints to form a pair of the semi-hollow body and the intermediate body. And a hollow body product is obtained therefrom. The invention according to claim 2 is
A fixed mold, a movable mold, and a slide mold provided between these molds, and the pair of molds include:
A concave portion for molding a pair of semi-hollow bodies, and a core portion for molding an intermediate interposed between the pair of semi-hollow bodies are provided at a predetermined interval, and the slide mold is provided. Is provided with a male die cooperating with the concave portion and a through hole cooperating with the core portion, and the first position of the slide die is set to a first position of the fixed die. In some cases, a cavity for molding the pair of semi-hollow bodies between the recess and the male mold, and a cavity for molding an intermediate between the core and the through-hole. When the second position of the slide mold is at the first position of the fixed mold, both open ends of the through hole substantially coincide with the openings of the recess. It is configured as follows.

[0006]

The present invention operates as follows. That is, the slide mold is slid so that its first position matches the first position of the fixed mold. Then, a cavity for forming a pair of semi-hollow bodies is formed between the concave portions of the pair of molds and the male mold of the slide mold. A cavity for molding an intermediate is formed between the cores of the pair of molds and the through-holes of the slide mold. A molten resin is injected into these cavities to form a pair of semi-hollow bodies and an intermediate body, respectively. Next, the slide mold is slid so that its second position coincides with the first position of the fixed mold. At this time, the pair of semi-hollow bodies are respectively held in the concave portions of the pair of molds, and the intermediate body is slid while being held by the slide mold. Alternatively, the pair of semi-hollow bodies is slid while being held by the projection of the slide mold, and the intermediate body is slid by being held by the projection of the fixed mold. Then, since both open ends of the through-holes of the slide mold substantially correspond to the openings of the recesses of the pair of molds, the joints of the pair of semi-hollow bodies and the joints of the intermediate body were abutted. State. The molten resin is injected into the joint and joined. Open the mold and take out the hollow body product.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A molding method according to the present embodiment includes a pair of semi-hollow bodies having a split shape, a primary molding method of molding an intermediate body interposed between the semi-hollow bodies with respective dies, and a primary molding method. It consists of a joint between a pair of semi-hollow bodies obtained by the primary molding method and a secondary molding method of joining the joint of the intermediate body with a molten resin using the same mold to obtain a hollow body product. ing. The type of resin for molding the pair of semi-hollow bodies A and B and the intermediate T and the type of resin injected in the secondary molding are not particularly limited. For example, a pair of semi-hollow bodies can be molded with polyphenylene sulfide PPS, and polyamide PA, nylon PA6, polyphenylene sulfide PPS, polycarbonate PC, polybutylene terephthalate PBT, or the like can be applied to secondary molding. When the same type of resin is used for the primary molding and the secondary molding, the resin is well-adjusted, and the weldability of the joint is improved even when injected at a low temperature and a low pressure. Further, since the type of the resin is the same, there is an advantage that the resin can be melted and recycled as it is. The mold apparatus used for carrying out the above-described molding method includes a fixed mold, a movable mold, a slide mold, and the like. Although the pair of semi-hollow bodies obtained by the primary molding need not necessarily be formed symmetrically, an example in which the pair is formed symmetrically will be described below.

First, an embodiment of the mold apparatus will be described.
The mold apparatus includes a fixed mold 1, a movable mold 1 'paired with the fixed mold 1, a slide mold 20 movably provided between the molds 1, 1', and the like. Have been.
The fixed mold 1 has a surface 2 that is in contact with the slide mold 20. Further, a concave portion 3 protruding inward from the surface 2 is provided. The recess 3 forms the outer surface of one semi-hollow body A, has a substantially hemispherical shape, and has a slide mold 2 described later.
A cavity 5 for forming the semi-hollow body A in cooperation with 0 is formed. Note that sprues, gates, and the like communicating with the cavity 5 are not shown. The fixed mold 1 is provided with a core portion 4 protruding outward from the surface 2 at a predetermined distance from the recess 3. The core portion 4 is for forming a half of the intermediate body T, and forms a front end surface portion 6 for forming a support portion H of the intermediate body T, a peripheral surface portion 7 for forming an inner surface, and a joint portion. And a ring-shaped convex portion 9 for performing the operation. There is a predetermined interval between the peripheral surface portion 7 and the convex portion 9 as illustrated. Therefore, the joint s of the intermediate T
Has an uneven shape. The movable mold 1 ′ is for forming the other half hollow body B and the other half of the intermediate body T,
In this embodiment, since the concave portion 3 ′, the core portion 4 ′, and the like are provided symmetrically with the fixed mold 1, the same reference numerals are denoted by a dash “′” and will not be described repeatedly.

The slide mold 20 is provided between the surface 2 of the fixed mold 1 and the surface 2 'of the movable mold 1', and is slidably driven in the vertical direction. Further, in the present embodiment, it can be moved in the left-right direction in the figure. The slide mold 20 has a width for forming the intermediate T,
At the upper part thereof, male molds 22, 22 'having elliptical or hemispherical cross sections projecting to both sides are provided. The diameters of the male molds 22, 22 'are smaller than the diameters of the recesses 3, 3' by a predetermined amount. Therefore, as shown in FIG. 1, when the slide mold 20 is slid so that the first position SK1 of the slide mold 20 coincides with the first position KK1 of the fixed mold 1 and the movable mold 1 ′, the concave portion is formed. Cavities 5, 5 'for forming semi-hollow bodies A, B having a predetermined thickness are formed between the male molds 22, 3' and the male molds 22, 22 '. The roots of the male molds 22 and 22 'are provided with ring-shaped projections 23 and 23' projecting outward at a predetermined distance from the base surface. As a result, a convex-concave mold is formed between the convex portions 23, 23 'and the base surfaces of the male molds 22, 22', and the cross section of the joining portion S of the semi-hollow body formed by this mold is , Becomes uneven.

Below the slide mold 20, there is provided a through hole 24 for molding the outer peripheral surface of the intermediate body T. The through-hole 24 penetrates the slide mold 20 in the axial direction, and the diameter of both open ends thereof is larger than the diameter of the peripheral surface 7 of the core 4 and substantially equal to the diameter of the openings of the recesses 3 and 3 '. equal. Therefore, the first position KK1 of the fixed mold 1 and the movable mold 1 '
When the first position SK1 of the slide mold 20 is moved, a cavity 25 for molding an intermediate body T having a predetermined thickness is formed between the through-hole portion 24 and the peripheral surface portion 7.
When sliding to the second position SK2, both open ends of the through hole 24 coincide with the openings of the recesses 3, 3 '.

Next, a method of forming a three-piece hollow body using the above-described mold apparatus will be described. As shown in FIG. 1, the first position SK1 of the slide mold 20 is slid to the first position KK1 of the fixed mold 1, and the movable mold 1 'is clamped by a known means. Then, cavities 5, 5 'for molding a pair of semi-hollow bodies B, A and a cavity 25 for molding the intermediate T are formed between the dies 1, 1', 20. . Therefore, although not shown in the figure, molten resin is injected from the injection machine through sprues, gates, and the like into these cavities 5, 5 ', and 25.
Inject into Then, the molten resin is filled in these cavities 5, 5 ', 25. The cavities 5, 5 'form a pair of semi-hollow bodies B, A having uneven joints S, S'. Similarly, the intermediate body T having the joints s and s ′ having the uneven shape and the support H having a predetermined thickness is formed by the cavity 25.

After cooling and solidification, the movable mold 1 'is opened a predetermined amount to the left in the figure. Then, the semi-hollow body B moves to the concave portion 3 'of the movable mold 1'. That is, the contact area between the outer surface of the semi-hollow body B and the inner surface of the concave portion 3 ′ of the movable mold 1 ′ is the difference between the inner surface of the semi-hollow body B and the outer surface of the male mold 22 ′ of the slide mold 20. Since the contact area is larger than the contact area, the semi-hollow body B has a larger adhesive force by a larger amount and is attached to the movable mold 1 'and opened. On the other hand, the intermediate body T remains in the through hole 24 of the slide mold 20. That is, the surface area where the intermediate body T contacts the distal end surface 6 ′, the peripheral surface 7 ′, etc. of the movable mold 1 ′ contacts the distal end surface 6, the peripheral surface 7 of the fixed mold 1 and the through-hole 24 of the slide mold 20. Because it is smaller than the surface area,
Intermediate T remains on slide mold 20.

Next, before the slide mold 20 is slid upward, the slide mold 20 is moved to the left in the figure by the male mold 2.
It moves slightly larger than the protrusion amount of 2. Also at this time, the semi-hollow body A remains in the fixed mold 1 due to the difference in the contact area between the concave portion 3 of the fixed mold 1 and the male mold 22 of the slide mold 20. Since the intermediate T tends to remain in the fixed mold 1, the intermediate T is moved while being attached to the slide mold 20 by appropriate means. Thereby, the semi-hollow body A is held by the fixed mold 1, the semi-hollow body B is held by the movable mold 1 ′, and the intermediate body T is held by the slide mold 20. In this state, the slide mold 20 is slid upward in the figure, and the joints s and s ′ of the intermediate body T are joined to the joints S and S of the semi-hollow bodies A and B.
It is positioned at S 'and the mold is clamped again so as to abut.
Then, ring-shaped joint spaces K and K 'are formed by the uneven joints s, s', S and S'. Next, a molten resin is injected from the injection machine into the joining spaces K and K ′ and filled. The state in which the injection filling has been completed is indicated by J in FIG. Note that the other space K 'is shown in an unfilled state for easy understanding. After cooling and solidifying, the movable mold 1 'and the slide mold 20 are simultaneously opened, for example. Then, the hollow product moves toward the movable mold 1 ′ and the slide mold 20 due to the difference in surface area as described above. The product is taken out by an ejector device or the like not shown. Hereinafter, the same operation is repeated to mold.

According to this embodiment, various effects can be obtained. For example, since the intermediate body T is joined to the joining portions of the semi-hollow bodies A and B on both sides, the support body H can be formed on the intermediate body T, and a hollow body product having high strength can be obtained. The area where the semi-hollow bodies A and B are in contact with the fixed mold 1 or the movable mold 1 ′ and the male mold 2 of the slide mold 20.
2 and 22 ', there is a difference between them, and when the mold is opened after the primary molding, the semi-hollow bodies A and B
And the movable mold 1 ', respectively, and the slide mold 20
The effect that secondary molding of injecting after sliding is easy is obtained. Further, since the intermediate body T is also in contact with the slide mold 20, if the movable mold 1 ′ and the slide mold 20 are simultaneously opened after the secondary molding, the product is moved between the movable mold 1 ′ and the slide mold 20. It is also easy to move around and take out products.

[0015]

As described above, according to the present invention, a three-piece hollow body product is manufactured by using a fixed mold, a movable mold, and a slide mold provided between these molds. Therefore, it is possible to obtain a hollow body product such as an intake manifold of an internal combustion engine and a large or medium-sized tank that requires internal strength. In addition, since a fixed mold, a movable mold, and a slide mold provided between these molds are used,
It has the characteristic that it can be molded by injection molding and can also produce hollow body products of complex shapes. Furthermore, since the pair of semi-hollow bodies are formed with the joints facing each other and the intermediate body interposed between these semi-hollow bodies is formed so that the joints are located on both sides, the slide metal Just by sliding the mold, the joint of the pair of semi-hollow bodies and the joint of the intermediate body abut. Therefore, there is also an advantage that the driving of the slide mold is simple, each process can be automated, and mass production of hollow body products can be performed.

[Brief description of the drawings]

FIG. 1 is a view showing an embodiment of a mold apparatus according to the present invention, and is a cross-sectional view showing a state before injection in which a first position of a slide mold is at a first position of a fixed mold.

FIG. 2 is a cross-sectional view showing a state in which a second position of a slide mold is at a first position of a fixed mold, and a joining portion of a pair of semi-hollow bodies and a joining portion of an intermediate body are joined. .

[Explanation of symbols]

 A, B Semi-hollow body T Intermediate body S, S ', s, s' Joint 1 Fixed mold 1 'Movable mold 3, 3' Concave part 4, 4 'Core part 5, 5' Cavity 20 Slide mold 22 , 22 'male mold 24 through hole 25 cavity

Claims (2)

(57) [Claims] 1. A fixed mold 1, a movable mold 1 ', and a slide mold 20 provided between these molds 1, 1'.
The pair of semi-hollow bodies A and B are placed in the molds 1, 1 ′ and 20 at the first positions KK 1 and SK 1 with their joints S and S ′ facing each other. The intermediate body T interposed between the hollow bodies A and B is located at the second position K of the molds 1, 1 ′ and 20.
K2 and SK2 are formed such that their joints s and s' are located on both sides, and then the slide mold 20 is moved to its second position SK.
2, the semi-hollow bodies A and B and the intermediate body T are slid to the first position KK1 of the fixed mold 1 or the movable mold 1 'to join these joints S, S', s, s. ′ Are held in contact with each other and these joints S,
A method for molding a three-piece hollow body product, comprising injecting a molten resin into S ′, s, and s ′ to obtain a hollow body product from a pair of semi-hollow bodies A and B and an intermediate body T. . 2. A fixed mold 1, a movable mold 1 ', and a slide mold 20 provided between these molds 1, 1'.
The pair of molds 1 and 1 ′ are interposed between the concave portions 3 and 3 ′ for forming the pair of semi-hollow bodies A and B, and the pair of semi-hollow bodies A and B. Core portions 4 and 4 'for molding an intermediate body T are provided at a predetermined interval, and the slide die 20 has male dies 22 and 22' cooperating with the recesses 3 and 3 '. And a through-hole portion 24 cooperating with the core portions 4 and 4 ′. The slide mold 20 has a first position SK 1 at a first position KK 1 of the fixed mold 1. At this time, the cavities 5, 5 'for molding the pair of semi-hollow bodies A, B between the recesses 3, 3' and the male molds 22, 22 '.
And a cavity 25 for molding an intermediate body T is formed between the core portions 4 and 4 ′ and the through-hole portion 24, respectively, and the slide mold 20 has a second position SK2. When the fixed mold 1 is at the first position KK1, both open ends of the through hole 24 substantially coincide with the openings of the recesses 3 and 3 '. Mold device for molding hollow body products.