JP4790332B2 - Resin molded body - Google Patents

Description

  The present invention relates to an improvement of a resin molded body in which a skin layer is formed on the surface of a molded body and an expanded layer having a large number of voids is formed inside.

In Patent Document 1, in a state in which a fixed mold having a recess formed on a molding surface and a movable mold incorporating a slide mold are closed, a fiber-filled thermoplastic resin is injected and filled in the cavity, In the process of solidifying the thermoplastic resin containing fibers, the elastic restoring force (spring) of the fibers compressed by the molding die by moving the slide mold backward in the direction of increasing the cavity volume in the movable mold By expanding by the back phenomenon, a rigid skin layer having no voids is formed on the entire surface, and a resin molded body having an expanded layer having a large number of voids formed therein is obtained. And in this resin molding, weight reduction can be achieved by the said expansion layer.
Japanese Patent Laid-Open No. 11-179751 (pages 3 and 7, FIG. 1)

  However, the expanded layer has the merit of reducing the weight, but it is also a fact that the rigidity is lowered. Therefore, for example, if a resin molded body in which the cylindrical mounting seat is integrally projected on the molded body is molded as described in Patent Document 1, the rigidity of the mounting seat is reduced.

Therefore, as shown in FIG. 8, a predetermined region b around the outer periphery of the mounting seat a and the mounting seat base is formed in a solid layer c having no gap to increase rigidity, while a skin layer e is formed on the surface of the molded body d. At the same time, it may be possible to reduce the weight of the resin molded body g by forming an expanded layer f having a large number of voids inside the molded body d, but the expanded cavity f is formed by expanding the cavity of the mold. In this case, a crack i occurs in the stepped portion h formed at the boundary between the solid layer c and the inflated layer e in the predetermined region b around the outer periphery of the mounting seat base, and the rigidity of the stepped portion h is reduced. As a result, the strength of the resin molded body g is lowered. It is considered that the crack i occurs in the stepped portion h because the skin layer e constituting the stepped portion h is pulled in the plate thickness direction by the expansion pressure when the expansion layer f is formed.

  The present invention has been made in view of the above points, and an object of the present invention is to prevent cracks from occurring at the step portion at the boundary between the solid layer and the expanded layer while being lightweight.

  In order to achieve the above object, the present invention is characterized in that the step portion at the boundary between the solid layer and the expanded layer is reinforced, and specifically, the following solution is taken.

That is, the invention according to claim 1 is a method in which, in the process of solidifying the fiber-filled thermoplastic resin injected and filled into the cavity of the mold, the cavity volume is expanded and the fiber-filled thermoplastic resin is expanded, so that the skin a tree butter molded expanded layer having a panel-shaped molded body formed therein with a plurality of voids along with the layer is formed on the surface, the above-mentioned molded body, a larger cavity volume during molding Without the expansion layer, a solid layer having a thickness smaller than that of the molded body is formed adjacent to the expansion layer, and the expansion layer is formed at the boundary between the solid layer and the expansion layer. stepped portion composed of a skin layer covering the integrally formed protruding in the thickness direction, the skin layer of the step portion is formed integrally continuous with the solid layer, the solid layer and the the step portion Step Thickness direction between the skin layer and the reinforcing ribs made of solid layer that is integrally connected is projected in the thickness direction spaced plurality, reinforcing ribs corresponding portion of the step portion, the solid layer of the molded body of And the skin layer of the stepped portion are integrally and continuously formed by the reinforcing ribs to form a thick, robust layer .

Invention according to claim 2, Te resin molding smell of claim 1, a solid layer corresponding part of the shaped body is integrally projects on one side of the solid layer, forming member main body A part mounting cylindrical mounting seat having an opening at the base end is formed so that the side base end is opened over the entire surface, and the solid is formed from the base end of the mounting seat to a predetermined region around the outer periphery of the mounting seat. The layer is integrally formed, the expansion layer is integrally formed around the outer periphery of the solid layer, and the step portion is formed at the boundary between the solid layer and the expansion layer .

According to the first aspect of the present invention, the skin layer is formed on the surface of the molded body, and the expansion layer having a large number of voids is formed inside the molded body, thereby reducing the weight of the resin molded body. . In addition, since the solid layer and the stepped portion are connected by projecting the reinforcing rib made of the solid layer at the stepped portion made of the skin layer at the boundary between the solid layer and the expanded layer, the portion corresponding to the reinforcing rib of the stepped portion is Even if the skin layer and the reinforcing ribs are continuously integrated into a thick, robust layer, and the expansion layer is formed, the skin layer constituting the stepped portion is pulled in the plate thickness direction by the expansion pressure in the mold cavity. Further, it is possible to sufficiently resist the expansion pressure and to avoid the occurrence of cracks in the stepped portion between the reinforcing ribs, and to ensure the strength of the resin molded body. Even if some cracks are generated at portions corresponding to the reinforcing ribs of the stepped portion, the rigidity of the stepped portion can be supplemented by the reinforcing rib .

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
3 is a perspective view of a resin carrier plate (door module) 1 constituting a part of a side door of an automobile as a resin molded body according to Embodiment 1 of the present invention, as viewed from the outside of the passenger compartment. The carrier plate 1 is assembled to the door inner panel 2b of the door body 2 composed of the door outer panel 2a and the door inner panel 2b, as indicated by phantom lines in FIG.

The carrier plate 1 includes a carrier plate main body (hereinafter referred to as a plate main body) 3 as a molded body, and a metal window as a component is provided on a surface on the outer side of the passenger compartment which is one side of the plate main body 3. Four round cylindrical mounting seats 7 for mounting the glass elevating rail 5 are integrally projected at four locations. A seal groove 9 is formed in the outer peripheral edge portion of the outer surface of the plate body 3 on the outer side of the passenger compartment, and the plate body 3 and the door inner panel 2b are sealed by the sealing material 10 accommodated in the seal groove 9. Is sealed (see FIG. 7). A plurality of cylindrical mounting seats 11 for attaching the carrier plate 1 to the door inner panel 2b are provided on the inner side of the seal groove 9 of the plate body 3 so as to protrude over the entire circumference with a predetermined interval. Yes. In FIG. 7, a door trim (not shown) is attached to the door inner panel 2b so as to cover the plate body 3 from the passenger compartment side.

  FIG. 1A is a cross-sectional view taken along the line I-I of FIG. 3, and A in FIG. 1B in the portion of the mounting seat 7 with the above-described window glass lifting rail 5 attached to the carrier plate 1. -A sectional view, FIG.1 (b) is a bottom view of the mounting seat 7 part corresponding to Fig.1 (a). FIG. 2A is a cross-sectional view taken along line II of FIG. 3 and is a cross-sectional view taken along the line B-B of FIG. FIG. 2B is a bottom view of the portion of the mounting seat 7 corresponding to FIG.

The mounting seat 7 includes a vertical wall 14 formed of a cylindrical body as a plate-like standing wall, and the vertical wall 14 has an opening 15 at the base end so that the base portion on the plate body 3 side is opened over the whole. A mounting surface portion 17 having a flat surface is formed at the tip facing the opening 15, and a bolt insertion hole 17 a is formed in the mounting surface portion 17.

The plate body 3 excluding the mounting seat 7 (vertical wall 14 and mounting surface portion 17) and the predetermined region 19 around the vertical wall (standing wall) base is heat containing fiber injected and filled into a cavity 41 of a mold 39 to be described later. In the process of solidifying the plastic resin P, the cavity volume corresponding to the plate main body 3 excluding the predetermined region 19 around the mounting seat 7 and the vertical wall base is enlarged, and the fiber-containing thermoplastic resin P is elastically restored to the fiber 21. By inflating with (expansion force), a hard skin layer 23 having no voids is formed on the surface, and an expansion layer 25 having a large number of voids (not shown) bulges inside the plate body 3 in the vehicle. It is formed inside. On the other hand, the predetermined area 19 around the mounting seat 7 and the vertical base of the vertical wall does not expand the cavity volume corresponding to the predetermined area 19 around the mounting seat 7 and the vertical wall base during molding. The solid layer 27 is thinner and harder than the plate body 3 , and the solid layer 27 is adjacent to the expansion layer 25 . And in this Embodiment 1, the predetermined area | region 19 around the said vertical wall base outer periphery is a perfect circle ring shape, and is formed on the said mounting seat 7 and a concentric circle. As described above, the skin layer 23 is formed on the entire surface of the plate body 3, and the expansion layer 25 having a large number of voids is formed inside the plate body 3, whereby the weight of the carrier plate 1 can be reduced. . Further, since the predetermined area 19 around the mounting seat 7 and the vertical wall base is formed of a solid solid layer 27 having no expansion layer 25, the rigidity of the predetermined area 19 around the mounting seat 7 and the vertical wall base is increased. Can be increased.

As the greatest feature of the present invention, there is no void at the boundary between the solid layer 27 and the expansion layer 25 in the predetermined region 19 around the periphery of the vertical wall base, and the solid skin layer 23 integrally covers the expansion layer 25. A round-shaped step portion 29 having a perfect circle shape is formed so as to protrude in the thickness direction, and the skin layer 23 of the step portion 29 is formed continuously and integrally with the solid layer 27 . Triangular reinforcing ribs 31, which are integrally connected to the solid layer 27 and the skin layer 23 in the plate thickness direction of the stepped portion 29, and are made of a solid layer 27 having no expansion layer 25, have a predetermined circumference around the vertical wall base. It is collision set radially in the thickness direction and a plurality of spaced circumferentially so as to connect the region 19 and the step portion 29. In this example, eight triangular reinforcing ribs 31 are provided, but the shape and number thereof are appropriately determined depending on the purpose and application. And the level | step-difference part 29 between these reinforcement ribs 31 can resist the expansion pressure at the time of formation of the expansion layer 25 mentioned later, and generation | occurrence | production of a crack is avoided.

  The carrier plate 1 having such a mounting seat 7 is formed as follows.

  At the time of molding, as shown in FIG. 4, the first mold 33 as a movable mold, the second mold 35 as a fixed mold disposed opposite to the first mold 33, and the first mold 33 A molding die 39 comprising a pressing block 37 that is movably inserted into the insertion hole 33a and is urged by an urging means (not shown) such as a spring so as to protrude toward the second mold 35 is prepared. To do. FIG. 4 shows the mold 39 corresponding to the cross section along the line AA in FIG. A circular recess 35a corresponding to the outer shape of the mounting seat 7 is formed on the second mold 35, and a protrusion 35b that forms the bolt insertion hole 17a of the mounting seat 7 protrudes from the bottom surface of the recess 35a. On the other hand, the pressing block 37 is formed with a cylindrical convex portion 37a corresponding to the inner shape of the mounting seat 7, and a triangular slit corresponding to the shape of the reinforcing rib 31 around the base portion of the convex portion 37a. A plurality of (eight) concave portions 37b are formed radially apart from each other in the circumferential direction.

First, as shown in FIG. 4, a thermoplastic resin P containing fibers such as glass fibers (for example, polypropylene resin containing fibers) from an injection machine (not shown) into the cavity 41 with the mold 39 closed. The injection filling. Thereafter, in the process in which the fiber-containing thermoplastic resin P is solidified in the cavity 41 of the mold 39, the first mold 33 is moved backward in the direction C in which the cavity volume increases, as shown in FIG. That is, the first mold 33 is slightly separated from the second mold 35, and the cavity volume corresponding to the plate body 3 excluding the holding block 37 (corresponding to the predetermined area 19 around the mounting seat 7 and the vertical wall base) is set. For example, the magnification is doubled or more. The thermoplastic resin P containing fibers forms a surface layer as a skin layer 23 having a high resin density by quickly cooling a portion of the mold 39 that comes into contact with the molding surface under the influence of mold temperature. On the other hand, the inner part of the fiber-containing thermoplastic resin P is hardly affected by the mold temperature and is in a highly viscous gel state. Therefore, by increasing the cavity volume, the fibers 21 compressed so far by the first mold 33 and the second mold 35 are released from the compression and elastically restored, and this elastic restoring force (springback phenomenon). That is, the fiber-containing thermoplastic resin P expands due to the expansion pressure. As a result, a rigid skin layer 23 having no voids is formed on the surface, and the expansion layer 25 having a large number of voids inside the plate body 3 excluding the predetermined region 19 around the mounting seat 7 and the vertical wall base. The carrier plate 1 is formed. Thereby, the weight reduction of the carrier plate 1 can be achieved as compared with the case where the plate body 3 is composed only of the solid layer 27 having no expansion layer 25 and has the same thickness as the plate body 3 of the present embodiment.

On the other hand, when the first mold 33 is moved backward, the holding block 37 is urged toward the second mold 35 and does not move backward, so that it corresponds to the predetermined area 19 around the mounting seat 7 and the outer periphery of the vertical wall during molding. The cavity volume to be expanded does not expand, the elastic recovery of the fibers 21 in the fiber-containing thermoplastic resin P is suppressed, and the predetermined region 19 around the outer periphery of the mounting seat 7 and the vertical wall base does not have the expansion layer 25. The rigid solid layer 27 is formed, and the rigidity of the predetermined region 19 around the outer periphery of the mounting seat 7 and the vertical wall base can be increased. Further, a round ring-shaped stepped portion formed of a rigid skin layer 23 that has no void at the boundary between the solid layer 27 and the expansion layer 25 in the predetermined region 19 around the base of the vertical wall and integrally covers the expansion layer 25. 29 is formed so as to protrude in the plate thickness direction, and the skin layer 23 of the stepped portion 29 is formed continuously and integrally with the solid layer 27. The stepped portion 29 includes the solid layer 27 and the stepped portion. A reinforcing rib 31 having a triangular shape, which is integrally connected to the skin layer 23 in the thickness direction 29 and includes the solid layer 27 having no expansion layer 25 , connects the predetermined region 19 and the stepped portion 29 around the base of the vertical wall. is collision set radially in the thickness direction a plurality of (eight) spaced circumferentially to connect. Thus, the reinforcing ribs 31 corresponding portion of the step portion 29 constitutes a robust layer of thick integrally and continuously with the skin layer 23 and the reinforcing ribs 31 of the solid layer 27 and the step portion 29 of the plate body 3, When the expansion layer 25 is formed, even if the skin layer 23 constituting the stepped portion 29 is pulled in the plate thickness direction by the expansion pressure of the expansion layer 25, that is, expanded, it can sufficiently resist the expansion pressure and the reinforcing rib 31. It is possible to avoid the occurrence of cracks in the stepped portion 29 therebetween, and the outer periphery of the mounting seat 7 of the plate body 3 can be strengthened to increase the support rigidity of the mounting seat 7 and to ensure the strength of the carrier plate 1. be able to. Even if some cracks are generated at portions corresponding to the space between the reinforcing ribs 31 of the stepped portion 29, the rigidity of the stepped portion 29 can be supplemented by the reinforcing rib 31.

  In the carrier plate 1 formed in this way, a circular cylindrical mounting seat 7 is integrally projected at four locations on the surface of the plate body 3 on the outer side of the passenger compartment. Then, as shown by phantom lines in FIG. 3, the window glass elevating rails 5 are respectively placed on the mounting surface portions 17 of the two mounting seats 7 arranged vertically on the left and right sides. At this time, the bolt insertion holes 5 a formed in the window glass elevating rail 5 are made to correspond to the bolt insertion holes 17 a of the mounting surface portion 17. Further, as shown in FIG. 1, a roller 43 for guiding a window glass raising / lowering wire (not shown) is placed on the window glass raising / lowering rail 5, and a bolt 45 is attached to a shaft hole (not shown) of the roller 43 and The nut 47 is inserted into the bolt insertion holes 5 a and 17 a and the nut 47 is screwed and fastened to the bolt 45 from the opening 15 side of the mounting seat 7 on the panel body 3 side, and the window glass lifting rail 5 is attached to the mounting seat 7.

(Embodiment 2)
FIG. 6 is a view corresponding to FIG. 1 showing Embodiment 2 of a carrier plate 1 as a resin molded body. In the second embodiment, contrary to the first embodiment, the expansion layer 25 is formed inside the plate body 3 so as to bulge outside the vehicle interior of the plate body 3. The reinforcing ribs 31 are also provided on the surface of the plate body 3 on the outer side of the passenger compartment. Therefore, although not shown, the mold structure of the molding die 39 is a fixed mold as the first mold 33 that forms the surface of the plate body 3 on the vehicle interior side, as opposed to the first embodiment. The second mold 35 forming the outer surface of the passenger compartment having the three expansion layers 25 is made movable, and the predetermined region 19 around the outer periphery of the mounting seat 7 and the vertical wall base is formed on the second mold 35 side. A holding block 37 is provided. Others may be configured in the same manner as in the first embodiment.

  Therefore, in the second embodiment, the same operational effects as in the first embodiment can be obtained.

(Embodiment 3)
FIG. 7 is a cross-sectional view taken along the line II-II in FIG. 3, showing Embodiment 3 of the carrier plate 1 as a resin molded body. In the third embodiment, as in the second embodiment, the expansion layer 25 is formed inside the panel main body 3 so as to bulge outside the vehicle interior of the plate main body 3. Further, in the outer peripheral edge portion 3a (where the seal groove 9 is formed) and the inner vicinity portion 3b on the outer surface of the plate body 3 on the outer side of the casing, the solid volume 27 that does not expand the cavity volume and does not have the expansion layer 25 at the time of molding. Is formed adjacent to the expansion layer 25. Further, a step portion 29 made of a skin layer is formed in the thickness direction at the boundary between the solid layer 27 and the expansion layer 25 in the inner vicinity portion 3b of the seal groove 9 formation portion. A plurality of reinforcing ribs 31 made of the solid layer 27 connecting the solid layer 27 and the stepped portion 29 in the portion where the seal groove 9 is formed and the inner vicinity 3b of the seal groove 9 are spaced apart from each other over the entire circumference of the plate body 3 and integrally project. In addition, the stepped portion 29 between the reinforcing ribs 31 can resist the expansion pressure when the expansion layer 25 is formed, and the generation of cracks is avoided. The outer end of the reinforcing rib 31 is connected to the inner wall 9a of the seal groove 9 integrally. Although not shown, the mold structure of the molding die 39 is the same as that of the second embodiment, and the first mold 33 that forms the interior surface of the plate body 3 is a fixed mold, and the plate body 3 A pressing block 37 that forms a movable mold in the second mold 35 that forms the outer surface of the passenger compartment having the expansion layer 25 and that forms the outer peripheral edge portion 3a and the inner peripheral portion 3b on the second mold 35 side. Is provided. Further, the molding surface shapes of the first mold 33, the second mold 35, and the holding block 37 are made to correspond to the shape of the carrier plate 1.

  Therefore, also in the third embodiment, the same operational effects as those of the first embodiment can be obtained. In particular, the outer peripheral edge of the plate body 3 can be strengthened.

In addition, in said Embodiment 1, 2, although the perfect cylindrical mounting seat 7 was illustrated, not only this but the elliptical or rectangular cylindrical mounting seat 7 may be sufficient. Further, the predetermined region 19 around the outer periphery of the vertical wall base is not limited to a perfect circle as in the first and second embodiments, but may be an elliptical shape or other shapes.

  Further, in the first and second embodiments, the case where the upright wall is the vertical wall 14 made of the cylindrical body of the cylindrical mounting seat 7 has been shown. It may be.

  Moreover, in said Embodiment 1-3, although the space | gap was formed in the inside of the panel main body 3 using the spring back phenomenon of the fiber 21, if a foaming material is contained in the thermoplastic resin P containing a fiber, it will move. When the back movement of the mold (first mold 33 in the first embodiment, second mold 35 in the second and third embodiments) is increased to increase the thickness of the plate body 3 in the movable mold retraction direction, the spring Even if the restoring force (expansion pressure) of the fiber 21 in the back phenomenon is insufficient, the foaming force (expansion pressure) of the foamed material can complement the restoring force of the fiber 21 and form a void reliably. In this case, examples of the foam material include a chemical foam material that generates gas by a chemical reaction, and a physical foam material that uses an inert gas such as carbon dioxide gas and nitrogen gas.

  Furthermore, in the first to third embodiments, the case where the resin molded body is the carrier plate 1 of the side door of the automobile is shown. However, other automobile panels such as instrument panels, door trims, trunk boards, etc. It can be applied to other charged products, residential panels, and the like.

  The present invention is useful for a resin molded body in which a skin layer is formed on the surface of a molded body and an expanded layer having a large number of voids is formed inside.

FIG. 1 (a) shows the first embodiment, and FIG. 1 (a) is a cross-sectional view taken along the line II of FIG. 3, and FIG. FIG. 1B is a bottom view of the mounting seat portion corresponding to FIG. 1A. FIG. 2 (a) shows the first embodiment, and FIG. 2 (a) is a cross-sectional view taken along the line I-I of FIG. 3, and FIG. FIG. 2B is a bottom view of the mounting seat portion corresponding to FIG. 2A. It is the perspective view which looked at the carrier plate which concerns on Embodiment 1 from the vehicle interior outer side. In Embodiment 1, it is a shaping | molding process figure of the AA cross section corresponding | compatible part of FIG.1 (b) which shows the state which injected and filled the thermoplastic resin containing a fiber in the cavity of a shaping | molding die. FIG. 1B shows a molding process diagram corresponding to the AA line cross-section in FIG. 1B showing a state in which the carrier plate is molded by slightly moving the first mold in the direction in which the cavity volume is increased in the first embodiment. It is. FIG. 3 is a diagram corresponding to FIG. In Embodiment 3, it is sectional drawing in the II-II line | wire of FIG. In a prior art example, it is an AA sectional view equivalent figure of Drawing 1 (b) in an attachment seat part.

1 Carrier plate (resin molding)
3 Plate body (molded body)
7 Mounting seat 14 Vertical wall (standing wall)
19 Predetermined area around the vertical wall base ( predetermined area around the outer periphery of the mounting seat )
21 Fiber 23 Skin layer 25 Expansion layer 27 Solid layer 29 Stepped portion 31 Reinforcement rib P Fiber-containing thermoplastic resin

Claims (2)

In the process of solidifying the fiber-filled thermoplastic resin (P) injected and filled into the cavity (41 ) of the mold (39) , by expanding the fiber volume and expanding the fiber-containing thermoplastic resin (P) , a tree butter molded body having a large number of expansion layer having a void (25) is formed panel-shaped molded body inside (3) together with the skin layer (23) is formed on the surface,
The molded body (3) does not have an expansion layer (25) without expanding the cavity volume during molding, and the solid layer (27) having a smaller plate thickness than the molded body (3) Formed adjacent to the inflatable layer (25) ,
On the boundary between the solid layer (27) and the expansion layer (25) , a stepped portion (29) made of a skin layer (23) that integrally covers the expansion layer (25) is formed to protrude in the plate thickness direction, step portion above the skin layer (29) (23) is formed integrally continuous with the solid layer (27), the solid layer in the step portion (29) (27) with the step portion (29 A plurality of reinforcing ribs (31) made of a solid layer (27) integrally connected to the skin layer (23) in the plate thickness direction are spaced apart and protruded in the plate thickness direction . The portion corresponding to the reinforcing rib (31) is such that the solid layer (27) of the molded body (3) and the skin layer (23) of the stepped portion (29) are integrally and continuously thickened by the reinforcing rib (31). A resin molded body comprising a solid layer . Te resin molding smell of claim 1,
The part corresponding to the solid layer (27) of the molded body (3) is integrally projected on one side of the solid layer (27), and the proximal end of the molded body (3) side is open throughout. A cylindrical mounting seat (7) for mounting a component having an opening (15) at the base end is formed,
The solid layer (27) is integrally formed in a predetermined region around the outer periphery of the mounting seat (7) from the base end of the mounting seat (7), and the expansion layer ( 25) is integrally formed, and the step portion (29) is formed at the boundary between the solid layer (27) and the expanded layer (25) .

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