JP4590904B2 - Plastic molded product - Google Patents

Description

  The present invention relates to a resin molded product. More specifically, the present invention relates to a resin molded product formed by joining at least two primary molded products by secondary molding.

  When a resin product having a complicated shape is produced in large quantities, it is generally formed by injection molding or extrusion molding. For example, in the case of injection molding, an injection mold is filled with a heated resin material, and then cooled, and the product is taken out.In particular, in the case of a product having a hollow product, it cannot be molded only by primary molding, The divided primary molded product is joined and formed by secondary molding. In order to join the divided primary molded products, there are known a method of joining by vibration welding and a method of joining by injecting a resin material into a joint part. For example, in the case of a hollow and complex product such as an intake manifold, the latter method of injecting a resin material into a joint having relatively few shape constraints, rather than vibration welding, which has many shape constraints due to the joining method. Has come to be adopted.

  One of the methods conventionally performed by the latter method is known, for example, from Patent Document 1. According to this, as shown in FIG. 8, the divided pair of primary molded products 50, 50 have joint portions 52, 52 from which the joint portions 51, 51 protrude. A large number of through holes 53 are formed in the joint portions 52 and 52 in a direction orthogonal to the joint surfaces facing the members, and a resin material for secondary molding is injected into each of the through holes 53 so that the pin member 54 and A joining member 55 is formed, and the pair of divided primary molded products 50 and 50 are joined together.

In addition, in such a method of filling and joining the divided primary product with a resin material, when forming a secondary molded product, use the secondary molding die also as the primary molding die. There were many. That is, the mold for forming each primary molded product is divided into a movable mold and a fixed mold, and the movable mold formed on one of the primary molded articles is moved toward the fixed mold formed on the other primary molded article. The butted surfaces. In many cases, a so-called DSI method is used in which secondary molding is performed by injecting a resin material for secondary molding into the flow path formed on each joint surface. In this method, when the pair of primary molded products are brought into contact with each other, the convex portion and the concave portion formed in the joint portion of the primary molded product are also fitted and joined.
JP-A-8-232788 (see pages 2 to 3 and FIG. 4)

  However, in the joint structure of the conventional secondary molded product shown in Patent Document 1, the joint portions 52 and 52 of the primary molded products 50 and 50 are joined to each other at the joint surfaces facing each other, and a through hole 53 is formed on the joint surface. is doing. And since it connects with the joint parts 52 and 52 with the connection member 55, and inject | pours the resin material into the through-hole 53, and joins as a some pin member 54, although a pair of primary molded products 50 and 50 can be joined firmly For example, when molding a long joint surface such as an intake manifold, if the joint member is warped or contracted and the accuracy of the joint surface is reduced, the injected resin material will be Leakage from the resin tends to decrease the resin pressure, resulting in poor bonding and insufficient filling.

  In addition, when the resin molded product performed by the DSI method is used to fit a pair of primary molded products, the convex portion and the concave portion of the portion to be fitted are, in most cases, the fitting surface is a surface perpendicular to the joint portion. Or since it is formed in the inclined surface about a draft angle, in the fitting state, the high sealing performance is not formed. Accordingly, when the resin material is injected, if the joint portion is warped or contracted, the accuracy of the joint surface is also lowered, and the resin leakage occurs as described above. In addition, since it cannot withstand a high resin pressure, it is necessary to provide a multipoint gate, which complicates the DSI mold and increases the cost.

  In addition, in the DSI method, since the primary molded product is subjected to secondary molding at a high temperature immediately after molding, secondary molding is performed in a state where the rigidity of the primary molded product is weak, so it cannot withstand high resin pressure. Resin leakage is likely to occur.

  The present invention solves the above-described problems.

In the present invention, a convex joint and a concave joint are provided on the primary molded products to be joined to each other. Furthermore, opposing surfaces are provided on the side surface of the convex joint and the side surface of the concave joint. And it has the sealing surface pressure generation means which generates a sealing surface in these opposing surfaces with the molding pressure at the time of secondary molding. A high sealing surface pressure can be generated by injecting a resin material into the flow path on the opposing surfaces of the convex joint and the concave joint. Accordingly, it is possible to prevent resin leakage flowing from the flow path to the outside.

Moreover, in this invention, the above-mentioned seal surface pressure generation means is comprised by making the rigidity of a convex junction part smaller than the rigidity of a concave junction part. Since the convex joint is easily deformed inside the concave joint and the concave joint located outside thereof is difficult to deform, the opposing surface of the convex joint is pressed toward the opposing surface of the concave joint. It becomes easy and the surface pressure of a fitting part can be made higher. Accordingly, it is possible to prevent the resin leakage by generating a higher sealing performance.

In the present invention, the seal surface pressure generating means is provided by a flow path of the resin material for secondary molding formed between both side surfaces of the convex joint portion. By positioning the flow path between both side surfaces of the convex joint, at least one side surface of the convex joint can be pressed toward the inner wall of the concave joint.

Moreover, in this invention, the flow path is divided by the convex side groove | channel formed in the convex junction part, and the concave side groove | channel formed in the concave junction part, and a convex side groove | channel is deeper than a concave side groove | channel.

  According to this configuration, by the pressure of the resin material for secondary molding, a large deformation force can be applied from the inside of the convex joint so that at least one side wall of the convex joint is deformed outward. it can.

Furthermore, in this invention, the flow path is divided by the convex side groove | channel formed only in the convex junction part. According to this configuration, by the pressure of the resin material for secondary molding, a large deformation force can be applied from the inside of the convex joint so that at least one side wall of the convex joint is deformed outward. it can.

Further, in the present invention, an inclined surface is formed on the side surface of the convex joint portion and the side surface of the concave joint portion, and the convex joint portion and the concave joint portion are press-fitted together with a press-fitting allowance. The inclined surfaces are brought into close contact with each other. Leakage of the resin material for secondary molding can be prevented by both the seal surface pressure accompanying the press-fitting and the seal surface pressure by the seal surface pressure generating means.

Further, in the present invention, each of the primary molded products is formed with a hook-like portion that protrudes outward and faces each other, and a convex joint and a concave joint are formed on the opposing surfaces of the hook-like portion. In addition, the non-opposing surface of the bowl-shaped portion is formed as a pressing surface that is sandwiched by the secondary molding die . By providing a hook-shaped part that protrudes to the outside of the primary molded product, the mating operation for fitting the convex joint part to the concave joint part is facilitated, and the secondary molding work for maintaining the fitting state during the secondary molding. It is possible to facilitate the adjustment of the fitting state or the like.

Further, in the present invention, the secondary molded product is formed by removing the primary molded product from the primary molding die and mounting the secondary molded product on a secondary molding die different from the primary molding die. Molding can be performed without causing a shortage of strength due to secondary molding at a high temperature immediately after.

  Next, an embodiment of the present invention will be described with reference to the drawings.

  One of the preferred embodiments of the present invention is a tubular resin molded product. In this resin molded product, the tube is bent linearly. The resin molded product is formed by joining at least two primary molded products. Each of the primary molded articles has a joint portion at a portion to be joined. The joint portion extends in a strip shape along the portion to be joined. Between the combined primary molded products, opposing joint surfaces extend in a band shape. The joint portion and the joint surface extend three-dimensionally due to the shape of the resin molded product.

  The present invention can be applied to an intake manifold having a long joint surface, for example, a three-cylinder internal combustion engine.

  1 and 2 show an intake manifold 1, which is a resin molded product formed by secondary molding. The intake manifold 1 includes three pipes 3 (3A, 3B, 3C) that are formed in a hollow shape, and a hollow surge tank 5 that communicates with one end of the pipes 3A, 3B, 3C. A connecting flange is formed on the other end side of the three pipes 3A, 3B, 3C. The other ends of the three pipes 3A, 3B, 3C are opened in the connecting flange.

  The intake manifold 1 is configured by joining a plurality of primary molded products 6 and 7. The primary molded product has a simple shape that can be molded. The primary molded products 6 and 7 are a pair of parts for constituting the intake manifold 1. The primary molded products 6 and 7 have a shape obtained by dividing the intake manifold 1 which is a resin molded product as a secondary molded product. The primary molded products 6 and 7 are molded by primary molding dies 20 and 21 shown in FIGS. 3 (a) and 3 (b). The primary molded products 6 and 7 are taken out from the primary molding dies 20 and 21. These steps are called primary forming steps. The primary molded products 6 and 7 are disposed between the secondary molding dies 22 shown in FIG. The secondary molding die 22 fixes the primary molded products 6 and 7 in combination with the shape of the intake manifold 1.

  The secondary molding die 22 strongly presses the hook-shaped portions protruding outward from the primary molded products 6 and 7. The secondary molding die 22 has a resin passage for injecting a resin material for secondary molding into a flow path formed between the primary molded products 6 and 7. When the resin material for secondary molding is injected into the flow path formed between the primary molded products 6 and 7, the primary molded products 6 and 7 are joined. The intake manifold 1 as a secondary molded product is taken out from the secondary molding die 22. These processes are called secondary forming processes.

  The primary molded products 6 and 7 are formed with joint portions 8 and 9 for joining them over the entire circumference, and tubulars serving as flow paths for the resin material for secondary molding at the joint portions of the joint portions 8 and 9. A passage 10 is formed. The tubular passage 10 extends corresponding to the joint surface of the resin molded product. The tubular passage 10 can be formed, for example, as a single passage, a plurality of branched passages, or an annular passage.

  In this embodiment, the tubular passage 10 is formed so as to go around the joint between the joint portions 8 and 9. A part of the tubular passage 10 is provided with an inlet for injecting the resin material for secondary molding, and a part is formed as an outlet at a position farthest from the inlet. In this embodiment, the injection port for injecting the secondary molding resin into the tubular passage 10 is formed at one end of one of the three pipes 3 (for example, the central pipe 3B). It becomes.

In the secondary molding, the primary molded products 6 and 7 are removed from the primary molding dies 20 and 21, and then the primary molded products 6 and 7 are combined and set in the secondary molding die 22. Moving the movable mold 22 a toward the fixed mold 22b, to fix the primary molded product 6,7. At this time, the tubular passage 10 formed between the primary molded products 6 and 7 is partitioned so that the resin material for the secondary molded product does not leak from the joint. After the secondary molding die 22 is closed, the heated resin material is injected into the flow path 10 formed in the joint portions 8 and 9 of the primary molded products 6 and 7, and is cooled and taken out.

  The joint portions 8 and 9 formed in the primary molded products 6 and 7 have a cross section shown in FIG. As shown in FIG. 3, a hook-like portion is formed protruding outward from the wall portion 300 of the pipe 3. The hook-shaped portion is provided in each of the primary molded products 6 and 7. The hook-shaped portion provides opposing surfaces that face each other, and also provides a pressing surface that is sandwiched by the secondary molding die 22 on the outside thereof. One joint portion 8 has a hook-like portion protruding outward and a convex joint 81 located on the opposing surface of the hook-like portion and directed to the other joint portion 9. The other joint portion 9 has a hook-like portion protruding outward and a concave joint portion 91 that is located on the opposite surface of the hook-like portion and accepts and fits the convex joint portion 81. is doing. The convex joint 81 extends as a line along the fitting surface. The concave joint portion 91 extends in a groove shape along the joint surface.

  The side surfaces on both sides outside the convex joint 81 and the side surfaces on both sides inside the concave joint 91 are formed with inclined surfaces facing each other. In this embodiment, both outer side surface portions of the convex joint portion 81 and both inner side surface portions of the concave joint portion 91 are formed as inclined surfaces over substantially the whole. The convex joint 81 is inserted and fitted into the concave joint 91. Moreover, the convex joint 81 and the concave joint 91 are press-fitted so as to press the inclined surfaces thereof. This press-fitted state is maintained during the injection of the secondary molding resin material after the primary molded products 6 and 7 are positioned between the secondary molding dies 22. Moreover, after the resin material for secondary molding is inject | poured and the resin material for secondary molding hardens | cures, the convex junction part 81 and the concave junction part 91 are press-fit in the secondary molding resin material hardening. It is held and fixed.

Before injecting the resin for secondary molding, the inclined surfaces 82 and 92 are abutted against each other, the tip surface 83 of the convex joint 81, the bottom surface 94 of the concave joint 91, and the tip surface 93 of the concave joint 91. A slight gap is formed between the bottom surface 84 of the convex joint 81. The center of this slight gap is formed as the center position O ₁ of the pair of joint portions 8 and 9 when the convex joint portion 81 and the concave joint portion 91 are joined.

  The convex joint 81 and the concave joint 91 are press-fitted and fitted with a press-fitting allowance. The press-fitting allowance generates a seal surface pressure that can prevent leakage of the resin material for secondary molding between the inclined surface of the convex joint portion 81 and the inclined surface of the concave joint portion 91, and maintains it. The range in which the amount of press-fitting of the convex joint into the concave joint can be changed.

  In this embodiment, the state illustrated in FIG. 4 is a standard press-fit amount. Further, the convex joint 81 can be further press-fitted into the concave joint 91 by the gap formed between the convex joint 81 and the concave joint 91. By this further press-fitting, the seal surface pressure between both inclined surfaces is maintained at a predetermined value or more.

  Further, even if the convex joint 81 is slightly retracted from the state illustrated in FIG. 4, the seal surface pressure between the two inclined surfaces is maintained by the elasticity of the convex joint 81 and the concave joint 91. By providing this press-fitting allowance, the press-fitting amount of the convex joint 81 into the concave joint 91 can be adjusted. By adjusting the amount of press-fitting within the range of the press-fitting allowance, it is possible to position the primary molded products 6 and 7 at a normal position as the intake manifold 1 while correcting warpage and shrinkage of the primary molded products 6 and 7, and the secondary product. Leakage of the molding resin material can be prevented.

A substantially semicircular groove 85 is formed from the front end surface 83 of the convex joint 81 toward the inside, and the center position O ₂ of the arc portion is convex from the center position C ₁ of the pair of joints. It is formed so as to be offset to the side.

  A substantially semicircular groove 95 is formed downward from the bottom surface 94 of the concave joint 91, and the tubular passage 10 is formed by abutting the groove 85 of the convex joint and the groove 95 of the concave joint 91. It will be.

  That is, the tubular passage 10 formed between the convex joint 81 and the concave joint 91 is formed wide on the convex joint 81 side and narrow on the concave joint 91 side.

  The flow path 10 is partitioned by a convex groove 85 formed on the top surface of the convex joint 81 and a concave groove 95 formed on the bottom surface of the concave joint 91. The convex groove 85 is deeper than the concave groove 95. As a result, the convex groove 85 is located between both side surfaces of the convex joint 81. Further, the flow path 10 is formed so as to greatly enter the convex joint portion 81 side from the concave joint portion 91 side in the cross section. In other words, the flow path 10 provides a wider pressure receiving area on the convex joint portion 81 side than on the concave joint portion 91 side. As a result, the resin material for secondary molding injected into the convex groove 85 deforms at least one side wall of the convex joint 81 toward the outside. In this embodiment, the side walls on both sides in the cross section of the convex joint 81 are deformed outward. Since the flow path 10 of the secondary molding resin material is formed inside the convex joint 81, the injected secondary molding resin material spreads the convex joint 81 in the width direction, The outer wall surface of the joint portion 81 is pressed against the inner wall surface of the concave joint portion 91. As a result, there is no gap between them. Therefore, the resin material for secondary molding acts so as to prevent the leakage itself.

  Accordingly, when the resin material for secondary molding is injected into the tubular passage (flow channel) 10, the convex joint 81 forms a wide groove 85, so that the inclined surface 92 of the concave joint 91 is formed by resin pressure. The pressure to be pressed is increased, and the surface pressure can be increased.

  Accordingly, a high sealing surface pressure is generated on the surface where the inclined surface 82 of the convex joint 81 and the inclined surface 92 of the concave joint 91 are fitted to prevent leakage of resin flowing from the tubular passage 10 to the outside. Can do.

  Note that the configuration in which the center position of the semicircular groove 85 of the convex joint 81 is offset is arranged so that the rigidity of the convex joint 81 is smaller than the rigidity of the concave joint 91. Thus, a high seal surface pressure can be generated.

  As described above, as a means for increasing the seal surface pressure acting between the inclined surface 82 of the convex joint portion 81 and the inclined surface 92 of the concave joint portion 91, the convex joint portion 81 in one joint portion 8 is used. It is possible to employ means for making the diameter smaller than the rigidity of the concave joint portion 91 in the other joint portion 9. In place of the configuration of FIG. 4, for example, as shown in FIG. 5, the tubular passage 10 formed by joining the convex joint 81 and the concave joint 91 is formed only in the convex joint 81, or It can also be formed so as to be provided almost on the convex joint 81 side. As a result, most of the resin pressure of the resin material injected into the tubular passage 10 can act so as to expand both side walls of the convex joint 81 to the outside, and high sealing performance can be exhibited.

As shown in FIG. 6, the center position O ₂ of the groove 85 (indicated by the radius a) of the convex joint 81 and the concave joint 91 with respect to the center position O ₁ of the pair of joint portions 8 and 9. The offset amount of the groove portion 95 (indicated by the radius b) with respect to the center position O ₃ may be substantially zero. That is, the center position O ₂ of the groove 85 of the convex joint 81 and the center position O ₃ of the groove 95 of the concave joint 91 substantially coincide with the center position O ₁ of the pair of joints. Even in this case, since the surface pressure can be applied to the inclined surface by the resin pressure by the injection of the resin material, the seal surface pressure can be generated. In this case, it is formed with the relationship between the horizontal thickness portion c and the horizontal width dimension d of the tip end portion of the convex joint 81 at the portion where the maximum load of the concave joint 91 is applied, and the tubular passage. The relationship between the vertical thickness dimension e of the convex joint 81 and the vertical thickness dimension f of the concave joint 91 may be c ≧ d and e ≧ f.

  Further, as shown in FIG. 7, one of the fitting surfaces of the convex joint 81 and the concave joint 91 is formed as an inclined surface, and the other fitting surface is fitted with a straight surface. It may be. In this case, the inclined surface is desirably formed on the side where the hollow portion 2 is formed in the case of the secondary molded product. In this embodiment, an inclined surface is formed on the side where the intake passage 2 as the intake manifold 1 is formed. The inclined surface is a surface that is inclined with respect to the protruding direction of the convex joint 81. The straight surface is a surface that extends substantially parallel to the protruding direction of the convex joint 81. The inclined surface is also a surface that is inclined with respect to the direction of the binding force applied from the secondary molding die 22 to the primary molded products 6 and 7.

As described above, in the joint part joint structure of the resin molded product according to the embodiment, one of the joint parts 8 and 9 of the pair of primary molded products 6 and 7 is formed in a convex shape and the other is formed in a concave shape. Then, the inclined surfaces 82 and 92 are formed so as to be fitted. The fitting in the press-fitted state, further, by injecting the resin material for secondary molding into a tubular passage 10 which forms a pair of joint portions between 8,9 and a pair of projections at the resin pressure of the injected resin material Since the seal surface pressure can be generated at the fitting portion between the cylindrical joint 81 and the concave joint 91, the resin leakage of the resin material injected into the tubular passage 10 can be prevented. Therefore, it is possible to form a secondary molded product (intake bear second hold 1) with good quality without any bonding failure.

  Further, of the pair of joint portions, the convex joint portion 81 is configured to be less rigid than the concave joint portion 91, for example, the center position of the groove 85 is shifted to the convex joint portion 81 side, or the convex joint portion 81 By forming the wall thickness to be smaller than the wall thickness of the concave joint portion, a higher sealing performance can be exhibited by the fitting portion.

It is a perspective view which shows the intake manifold as a general resin molded product. It is II-II sectional drawing in FIG. It is a conceptual diagram which shows the type | mold for primary shaping | molding, and the type | mold for secondary shaping | molding. It is sectional drawing which shows the joint part junction structure of the resin molded product of one form of this invention. It is sectional drawing which shows the joint part junction structure of the resin molded product by another form. Furthermore, it is sectional drawing which shows the joint part junction structure of the resin molded product by another form. Furthermore, it is sectional drawing which shows the joint part junction structure of the resin molded product by another form. It is sectional drawing which shows the joint part junction structure of the conventional resin molded product.

Explanation of symbols

1, Intake manifold 3, Pipe 5, Surge tank 6, Primary molded product 7, Primary molded product 8, Joint part 9, Joint part 10, Tubular passage (flow path)
81, convex joint 82, inclined surface 85, groove 91, concave joint 92, inclined surface 95, groove

Claims (5)

A plurality of primary molded products are each formed with a joint part for joining, a convex joint part is formed on one joint part, a concave joint part is formed on the other joint part, and a joint part of both joint parts Are formed so that they can be fitted together, and a flow path for injecting a resin material for secondary molding is formed in the joint portion of the joint parts, and the resin material is injected to form a secondary molded product. It is a resin molded product formed as
The side surfaces of the convex joint portion and the side surfaces of the concave joint portion are opposed to each other, and the joint portion of the joint portion is sealed between the opposing surfaces by molding pressure during secondary molding. Having seal surface pressure generating means for generating pressure,
The sealing surface pressure generating means includes the flow path formed between both side surfaces of the convex joint, and the flow path includes a convex groove formed in the convex joint and the concave joint. The convex groove is formed deeper than the concave groove, and the rigidity of the convex joint is smaller than the rigidity of the concave joint. Characteristic resin molded product. A plurality of primary molded products are each formed with a joint part for joining, a convex joint part is formed on one joint part, a concave joint part is formed on the other joint part, and a joint part of both joint parts Are formed so that they can be fitted together, and a flow path for injecting a resin material for secondary molding is formed in the joint portion of the joint parts, and the resin material is injected to form a secondary molded product. It is a resin molded product formed as
The side surfaces of the convex joint portion and the side surfaces of the concave joint portion are opposed to each other, and the joint portion of the joint portion is sealed between the opposing surfaces by molding pressure during secondary molding. Having seal surface pressure generating means for generating pressure,
The seal surface pressure generating means includes the flow path formed between both side surfaces of the convex joint, and the flow path is partitioned by a convex groove formed only in the convex joint, A resin molded product comprising a convex joint having a rigidity smaller than that of the concave joint. A plurality of primary molded products are each formed with a joint part for joining, a convex joint part is formed on one joint part, a concave joint part is formed on the other joint part, and a joint part of both joint parts Are formed so that they can be fitted together, and a flow path for injecting a resin material for secondary molding is formed in the joint portion of the joint parts, and the resin material is injected to form a secondary molded product. It is a resin molded product formed as
The side surfaces of the convex joint portion and the side surfaces of the concave joint portion are opposed to each other, and the joint portion of the joint portion is sealed between the opposing surfaces by molding pressure during secondary molding. Having seal surface pressure generating means for generating pressure,
The seal surface pressure generating means is formed such that the rigidity of the convex joint is smaller than the rigidity of the concave joint;
A resin molded product, wherein the secondary molded product is molded by taking out the primary molded product from a primary molding die and mounting the secondary molded product on the secondary molding die different from the primary molding die. An inclined surface is formed on the side surface of the convex joint portion and the side surface of the concave joint portion, and the convex joint portion and the concave joint portion are press-fitted with a press-fitting allowance, and the slope is formed. 3. The resin molded product according to claim 1, wherein the surfaces are brought into close contact with each other. Each of the primary molded products has a hook-like portion that protrudes outward and faces each other, and the convex joint and the concave joint are formed on the opposing surface of the hook-shaped portion. 5. The resin molded product according to claim 1, 2 or 4, wherein a surface of the flange-shaped portion that is not opposed is formed as a pressing surface that is sandwiched by a secondary molding die.

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