JP2011207118A - Foamed resin panel and molding die of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a foamed resin panel with high rigidity of a thin-walled panel part.SOLUTION: A bonnet hood 1 includes a thick-walled panel part 15 with a skin layer 19, consisting of a solid layer, formed on a surface thereof and a foamed layer 21 with lower resin density than the skin layer 19, formed internally in one piece; and a thin-walled panel part 17 which is adjacent to the thick-walled panel part 15 and formed of a solid layer molded integrally with the skin layer 19 during molding of the thick-walled panel part 15. In addition, in the bonnet hood 1 where a stepped part 15a including the skin layer 19, is formed in the panel thickness direction at the border between the thick-walled panel part 15 and the thin-walled panel part 17, a reinforcement rib 25 is formed integrally with the thick-walled panel part 15 and the thin-walled panel part 17 so as to straddle the stepped part 15a. Further, the reinforcement rib 25 is allowed to project from the surface on the thin-walled panel part 17 side, and further is fused with the skin layer 19 by wedging into the thick-walled panel part 15 on the thick-walled panel part 15 side.

Description

  The present invention relates to a foamed resin panel injection-molded by a core back method (Moving Cavity method) and a molding die thereof, and particularly relates to measures for increasing the rigidity of a thin portion of the foamed resin panel.

  In Patent Document 1, the skin layer is formed by a core back method in which the cavity volume is expanded and the fiber-containing thermoplastic resin is foamed in the process of solidifying the fiber-containing thermoplastic resin injected and filled into the cavity of the mold. A thick panel portion formed on the surface and having a foam layer having a large number of voids formed therein, and a thin panel portion made of a solid layer having no foam layer without expanding the cavity volume during molding. A foamed resin panel is disclosed. In this foamed resin panel, a reinforcing rib made of a solid layer is integrally projected on the thin panel portion so as to be connected to a stepped portion made of a skin layer formed at the boundary between the thick wall panel portion and the thin wall panel portion. ing.

JP 2007-7941 A

  FIG. 11 is a molding process diagram of a foamed resin panel, (a) shows a filled state of the thermoplastic resin R, and (b) shows a volume expanded state of the thick panel part molding cavity. FIG. 12 is a cross-sectional view of a main part of the foamed resin panel 201.

  The foamed resin panel having the reinforcing ribs as described above is molded using a molding die 301 shown in FIGS. The mold 301 includes a fixed mold 303 and a movable mold 305. On the molding surface of the fixed mold 303, an outer surface resin layer 203 constituting the panel outer surface side is molded in advance. The movable mold 305 includes a movable core mold 307 corresponding to the thick panel section 205 and a fixed core mold 309 corresponding to the thin panel section 207, and a groove 309a for forming a reinforcing rib is formed in the fixed core mold 309. ing.

  Then, as shown in FIG. 11A, the mold 301 closes the fixed mold 303 and the movable mold 305, and enters the cavity 311 formed between the outer resin layer 203 and the movable mold 305. By injecting and filling the thermoplastic resin R and solidifying the thermoplastic resin R, as shown in FIG. 11B, the movable core mold 307 is moved backward in the mold opening direction to enlarge the cavity volume. The thermoplastic resin R corresponding to the movable core mold 307 is foamed to form the thick panel portion 205 having the foamed layer 211 inside the skin layer 209, while the thermoplastic resin R corresponding to the fixed core mold 309 is The thin panel portion 207 and the reinforcing rib 213 made of a solid layer are molded as it is.

  However, in the method of molding the foamed resin panel by the core back method as described above, when expanding the cavity volume, the skin layer that has started to solidify quickly near the boundary between the movable core mold 307 and the fixed core mold 309 is stretched. The expansion | swelling by foaming of the thermoplastic resin R inside the said skin layer vicinity is prevented. For this reason, the thermoplastic resin R portion constituting the step portion 205a of the thick panel portion 205 is separated from the molding surface of the movable core mold 307, and a so-called “Ardale” phenomenon occurs at the corner portion of the thick panel portion 205 continuous with the step portion 205a. Occurs. As a result, a gap S is formed between the reinforcing rib 213 protruding from the thin panel portion 207 and the step portion 205 a of the thick panel portion 205. In the foamed resin panel 201 obtained in this way, as shown in FIG. 12, the connecting portion between the stepped portion 205a of the thick panel portion 205 and the reinforcing rib 213 is small, so that the reinforcing rib 213 easily swings. The reinforcing function of the thin panel portion 207 cannot be sufficiently exhibited, and the rigidity of the thin panel portion 207 cannot be satisfactorily increased.

  This invention is made | formed in view of such a point, The place made into the objective is to provide the foamed resin panel with the high rigidity of a thin-walled panel part.

  In order to achieve the above object, the present invention devised the structure of the connecting portion between the reinforcing panel for reinforcing the thin panel portion and the thick panel portion, and specifically, the following solution was taken. .

  That is, according to the first aspect of the present invention, there is provided a thick panel portion in which a skin layer made of a solid layer is formed on the surface, and a foam layer having a resin density lower than that of the skin layer is integrally formed therein. A thin panel portion formed of a solid layer integrally formed with the skin layer at the time of molding the thick panel portion adjacent to the portion, and the skin layer at the boundary between the thick panel portion and the thin panel portion The foamed resin panel in which the stepped portion is formed in the plate thickness direction, and the reinforcing rib is integrally formed on the thick panel portion and the thin panel portion so as to straddle the stepped portion. The thin panel portion side protrudes from the surface, and the thick panel portion side bites into the thick panel portion and is fused with the skin layer.

  2nd invention is a shaping | molding die which shape | molds the foamed resin panel of 1st invention, Comprising: The 1st type | mold which shape | molds the one panel surface side of the said foamed resin panel, and arrange | positions facing the said 1st type | mold. And a second mold in which a cavity for molding the foamed resin panel is formed between the first mold, and the first mold is disposed so as to correspond to the thin panel portion. And the position of the mold surface of the initial stage where the thermoplastic resin is injected and filled is set as the first position adjacent to the fixed core mold so as to correspond to the thick panel portion, and from the first position to the above A movable core mold movable to a second position corresponding to the thickness of the thick panel portion, and the fixed core mold includes a first groove portion for molding the thin panel portion side of the reinforcing rib. The fixed core mold is formed so as to open to the mold facing side and the second mold side. On the opposite side of the movable core mold, a convex portion protrudes so as to correspond to an open portion of the first groove portion on the opposite side of the movable core mold, and the convex portion is provided on the movable core mold. A concave portion that is slidably fitted in the moving direction is formed so as to open to the fixed core type facing side and the second type side, and the movable core type has the fixed core in a state of being positioned at the first position. A second groove portion for forming the thick panel portion side of the reinforcing rib is formed continuously with the first groove portion in cooperation with the convex portion of the mold and the concave portion. From this state, the movable core die is moved to the first groove portion. The thermoplastic resin is configured to foam in the cavity corresponding to the movable core mold by moving the cavity volume to two positions and expanding the cavity volume.

  According to the first invention, the reinforcing rib formed over the thick panel portion and the thin panel portion protrudes from the surface of the thin panel portion and bites into the stepped portion of the thick panel portion. By being fused, it is firmly held by the portion that has bite into the thick panel portion, so that the rigidity of the thin panel portion can be reliably increased by the reinforcing structure by the reinforcing rib.

  According to the second invention, the second groove portion that forms the thick panel portion side of the reinforcing rib in combination with the convex portion of the fixed core type and the concave portion of the movable core type forms the thin panel side of the reinforcing rib. Since it is formed so as to be continuous with the first groove, even when an Aardare phenomenon occurs in the corner portion that continues to the stepped portion of the thick panel portion during foam molding of the thick panel portion, the second groove portion is filled. The cured thermoplastic resin is solidified without being affected by the expansion of the cavity volume, so that a reinforcing rib continuous with the thin panel portion side can be formed on the thick panel portion side so as to straddle the stepped portion. Reinforcing ribs can be sandwiched from both sides at the meat panel. Therefore, the foamed resin panel having a sufficient area for reinforcing the thin panel portion as described above can be molded with the reinforcing rib having a sufficient area and surely connected to the thick panel portion. Can do.

It is a reverse view which shows the bonnet hood which concerns on Embodiment 1. FIG. It is a perspective view which expands and shows the rear side attachment part of a bonnet hood. FIG. 3 is a perspective sectional view taken along line III-III in FIG. 2. It is sectional drawing in the IV-IV line of FIG. It is sectional drawing in the VV line of FIG. It is a shaping | molding process figure of the outer surface resin layer in shaping | molding of a bonnet food | hood. The thermoplastic resin filling state for base-material resin layer shaping | molding in shaping | molding a bonnet hood is shown, (a) is sectional drawing in the location corresponding to FIG. 4, (b) is sectional drawing in the location corresponding to FIG. The state which the thermoplastic resin for base-material resin layer shaping | molding in shaping | molding of a bonnet hood started to solidify is shown, (a) is sectional drawing in the location corresponding to FIG. 4, (b) is sectional drawing in the location corresponding to FIG. The volume expansion state of the thick panel part shaping | molding cavity in shaping | molding of a bonnet hood is shown, (a) is sectional drawing in the location corresponding to FIG. 4, (b) is sectional drawing in the location corresponding to FIG. It is the top view which looked at the principal part of the 2nd movable mold in a bonnet food mold from the mold forming surface side. It is a shaping | molding process figure of the foamed resin panel using the technique of a prior art document, (a) shows a thermoplastic resin filling state, (b) shows the volume expansion state of the thick panel part shaping | molding cavity. It is principal part sectional drawing of the foamed resin panel using the technique of a prior art document.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited to the following embodiment.

<< Embodiment of the Invention >>
FIG. 1 is a back view showing a bonnet hood 1 which is a foamed resin panel of this embodiment.

  The bonnet hood 1 is a plate-like component that extends in the vehicle longitudinal direction and the vehicle width direction, and is attached so as to cover the engine room in front of the vehicle body. The bonnet hood 1 has a symmetrical trapezoidal shape in which the width gradually narrows toward the front of the vehicle body, and is gently curved in the width direction so that the center portion in the width direction is located in front of the vehicle body than the both side portions. Yes.

  In the vicinity of both ends in the vehicle body rear side width direction on the rear surface of the hood hood 1, rear side attachment portions 3 for attachment to the vehicle body are provided. A fastening member 5 is inserted into each of the rear mounting portions 3 and a pair of male screws 5a of the fastening member 5 protrudes from the surface. Although not shown, for example, the male bracket 5a of the fastening member 5 has a hinge bracket 5a. Is fastened with a nut, and the hinge bracket is attached to the vehicle body via the hinge, so that the rear end portion of the bonnet hood 1 can be rotatably fixed to the vehicle body.

  Further, a front attachment portion 9 for attachment to the vehicle body is provided at the center in the width direction of the vehicle front side on the rear surface of the hood 1. A fastening member 5 is also inserted into the front attachment portion 9 and a pair of male screws 5a of the fastening member 5 protrude from the surface. Although not shown, for example, a striker is a nut on the male screw 5a of the fastening member 5. The bonnet hood 1 can be fixed to the vehicle body by being fastened and locking the striker to a latch mechanism attached to the vehicle body.

  The rear mounting part 3 of the bonnet hood 1 and the structure in the vicinity thereof are shown in FIGS. 2 is an enlarged perspective view showing the rear attachment portion 3 of the bonnet hood 1 and the vicinity thereof, FIG. 3 is a perspective sectional view taken along line III-III in FIG. 2, and FIG. 4 is IV-IV in FIG. 5 is a cross-sectional view taken along the line V-V in FIG. In the following description, the rear attachment portion 3 is described with reference to the drawings, but the front attachment portion 9 has the same structure as the rear attachment portion 3.

  As shown in FIGS. 2 to 5, the bonnet hood 1 includes an outer surface resin layer 11 constituting the outer surface side, and a base resin layer 13 integrally formed on the back surface of the outer surface resin layer 11.

  The outer surface resin layer 11 is made of a thermoplastic resin such as ABS (Acrylonitrile Butadiene Styrene) resin or polypropylene, and is composed of a solid layer having a high resin density. This outer surface resin layer 11 is for forming a smooth outer surface of the bonnet hood 1 and is formed as thin as possible for weight reduction and can be molded by injection molding, for example, 1.8 mm to 2.3 mm. It is about the thickness. As shown in FIG. 4, a peripheral wall portion 11 a protrudes from the outer peripheral edge of the outer surface resin layer 11 on the back surface side as shown in FIG. 4, and the peripheral wall portion 11 a forms the outer edge of the hood hood 1 as shown in FIG. 1. is doing.

  The base resin layer 13 is made of an ABS resin containing a long fiber such as glass fiber, carbon fiber, or plant fiber, or a thermoplastic resin such as polypropylene. The inclusion of the long fiber increases the rigidity and increases the linear expansion coefficient. Is kept low. The base resin layer 13 is for securing the rigidity of the hood hood 1 and is the main body of the hood hood 1, and is provided on the entire back surface of the outer resin layer 11 inside the peripheral wall portion 11 a. It has been.

  As shown in FIG. 1, the base resin layer 13 includes a thick panel portion 15 provided on the back surface portion of the outer surface resin layer 11 excluding the rear and front attachment portions 3 and 9 of the bonnet hood 1, The thin panel portion 17 is provided adjacent to the thick panel portion 15 on the back surface portion of the outer resin layer 11 of the rear and front mounting portions 3 and 9.

  The thick panel portion 15 has a thickness of about 2.5 mm to 7 mm, for example. As shown in FIGS. 3 to 5, a skin layer 19 made of a solid layer having a high resin density is formed on the entire surface, Inside the skin layer 19, a foam layer 21 having a large number of voids and having a resin density lower than that of the skin layer 19 is integrally formed. Thus, the thick panel part 15 which has the foaming layer 21 in the inside comprises the base resin layer 13, and the weight reduction of the bonnet food | hood 1 is achieved.

  In the skin layer 19 on the back side of the thick panel portion 15, as shown in FIG. 1, ribs 23 made of a solid resin for preventing deformation due to heat change of the bonnet hood 1 are formed in a net-like shape over the entire area. More specifically, for example, a frame shape along the outer peripheral edge portion of the thick panel portion 15 and a lattice shape in which linear bodies extending in the left-right oblique direction with respect to the front-rear direction are combined and projected in the frame. Yes. Thus, when a heat change is applied to the hood hood 1, expansion or contraction occurs on both sides of the base resin layer 13 in a well-balanced manner by the outer surface resin layer 11 and the ribs 23 with respect to the entire hood hood 1. It is possible to prevent the hood 1 from being deformed such as warpage.

  The rib 23 faces the engine with the hood 1 closed. As a result, when a person collides with the hood hood 1 and a large impact such as a so-called head impact is applied to the hood hood 1, the hood hood 1 is deformed at the location, and the rib 23 is By striking the opposing engine and buckling, and the foamed layer 21 is crushed, impact energy can be absorbed efficiently and the impact on the occupant can be mitigated. The rib 23 has a height of about 10 mm to 20 mm and a width of about 0.5 mm to 2.5 mm, which is difficult to include the long fiber in a molding process described later. Is not included or a small amount is included.

  On the other hand, the thin panel portion 17 has a thickness of about 1.5 mm to 4 mm, for example, and is formed of a solid layer integrally formed with the skin layer 19 when the thick panel portion 15 is molded. Is integrally inserted. In this way, the fastening member 5 is inserted into the thin panel portion 17 made of a solid layer that is harder than the thick panel portion 15 including the foam layer 21 therein, so that the fastening strength of the fastening member 5 to the bonnet hood 1 is increased. Has been increased.

  As shown in FIGS. 2 to 4, a step portion 15 a made of the skin layer 19 of the thick panel portion 15 is formed in the thickness direction at the boundary between the thick panel portion 15 and the thin panel portion 17 described above. It presents a side facing the hood side or front-rear direction. The thick panel portion 15 and the thin panel portion 17 are integrally formed with a plurality of reinforcing ribs 25 that reinforce the thin panel portion 17 at predetermined intervals so as to straddle the stepped portion 15a. Each of these reinforcing ribs 25 is, for example, the same height as the stepped portion 15a. The thin panel portion 17 protrudes from the surface, and the thick panel portion 15 bites into the thick panel portion 15 and fuses with the skin layer 19. is doing. That is, as shown in FIG. 5, in the peripheral portion of the reinforcing rib 25 of the thick panel portion 15, the skin layer 19 on the back side falls inward and is integrally connected to the reinforcing rib 25. The inside of the portion 15 extends from the back surface side to the skin layer 19 on the front surface side and is integrally connected to the skin layer 19.

-Mold for bonnet hood 1-
The bonnet hood 1 as described above can be molded using a molding die 101 as shown in FIGS. Each of FIG. 6 and FIGS. 7 to 9 shows a portion corresponding to FIG. 4, and each of FIG. 7 to FIG. 9B shows a portion corresponding to FIG. Moreover, in these FIGS. 6-9, the left side in the figure is the surface side of the bonnet hood 1, and the right side in the figure is the back side of the bonnet hood 1. FIG. 10 is a view of the main part of the second movable mold 107 as viewed from the mold forming surfaces 111b and 113a. For convenience, the fixed core mold 111 side is indicated by hatching.

  The mold 101 includes a fixed mold 103 that is a second mold for molding the outer surface resin layer 11 of the bonnet hood 1 and a first movable mold 105 (see FIG. 6). Moreover, the 2nd movable mold | type 107 which is a 1st type | mold for carrying out the injection molding of the base resin layer 13 of the bonnet food | hood 1 with the said fixed mold 103 is also provided (refer FIG. 7).

  The fixed mold 103 has a recess 103a for panel molding, and a molding surface 103b corresponding to the surface shape of the outer resin layer 11 is formed on the inner surface of the recess 103a (see FIG. 6). The first movable mold 105 has a convex part 105a that protrudes toward the fixed mold 103 so as to correspond to the concave part 103a of the fixed mold 103, and an outer surface resin layer on the surface of the convex part 105a and its surrounding surface. 11 is formed (see FIG. 6). The first movable mold 105 is in a mold-closed state, and the convex part 105a is fitted into the concave part 103a to the middle part of the fixed mold 103 that is separated from the side wall and the lower wall, and the molding surface 103b is fixed mold. A cavity 109 for molding the outer surface resin layer 11 is formed between the molding surface 103b and the molding surface 103b.

  The second movable mold 107 includes a fixed core mold 111 disposed at a position corresponding to the thin panel portion 17, that is, a position corresponding to the rear and front mounting portions 3 and 9, and adjacent to the fixed core mold 111. And the movable core type | mold 113 arrange | positioned in the location corresponding to the thick panel part 15 is provided (refer FIG. 7).

  In the fixed core mold 111, a first groove 111a for forming the thin panel portion 17 side of the reinforcing rib 25 is formed so as to open to the movable core mold 113 facing side and the fixed mold 103 side. A molding surface 111b corresponding to the back surface shape of the thin panel portion 17 is configured including the one groove portion 111a. Although not shown, a holding concave portion into which the male screw 5a of the fastening member 5 can be inserted is formed on the molding surface 111b of the fixed core mold 111, and the holding concave portion has a magnet inserted therein to generate magnetic force. The fastening member 5 is held.

  Further, on the opposite side of the fixed core mold 111 to the movable core mold 113, a flat convex portion corresponding to the open portion of the first groove 111a facing the movable core mold 113 and adjacent to the open portion. 111c protrudes and is located in the location corresponding to the thick panel part 15 side of the reinforcement rib 25. FIG. The thickness of the convex portion 111c matches the width of the first groove portion 111a as shown in FIG.

  The movable core mold 113 has a molding surface 113a corresponding to the back surface shape excluding the portion where the reinforcing rib 25 of the thick panel portion 15 is formed, and the position of the mold molding surface 113a at the initial stage for injection-filling the thermoplastic resin (see FIG. 7 is the first position, and from a first position toward the second position (the position shown in FIG. 9) corresponding to the thickness of the thick panel portion 15 by the operation of a hydraulic cylinder (not shown). It is configured to be movable in the mold opening direction. In the movable core mold 113, the convex portion 111c of the fixed core mold 111 is slidably inserted in the anti-movable core mold moving direction, that is, is inserted so as to be relatively slidable by the movement of the movable core mold 113. The recessed portion 113b is formed so as to open to the fixed core mold 111 facing surface and the fixed mold 103 side. In the movable core mold 113, the thick panel portion 15 side of the reinforcing rib 25 is formed by jointing the convex portion 111c and the concave portion 113b of the fixed core mold 111 in a state of being located at the first position. The second groove portion 113c is formed continuously with the first groove portion 111a, and the second groove portion 113c constituting surface of the convex portion 111c is formed on the molding surface 113a of the movable core mold 113 in a state of being located at the second position. Positioned flush. In addition, although not shown, a narrow groove portion for forming the rib 23 for preventing the deformation of the bonnet hood 1 is also formed on the molding surface 113a of the movable core mold 113.

  The second movable mold 107 is configured so that the fixed core mold 111 and the movable core mold 113 are directly above the recess 103a of the fixed mold 103 so that the molding surfaces 111b and 113a are positioned flush with each other in the initial stage of the mold closed state. And a cavity for molding the base resin layer 13 between the molding surfaces 111b and 113a of the fixed core mold 111 and the movable core mold 113 and the back surface of the outer resin layer 11 previously molded on the fixed mold 103. 115 is formed, and from this state, the movable core mold 113 is moved in the mold opening direction so that the cavity volume corresponding to the movable core mold 113 can be enlarged.

-Molding method of bonnet hood 1-
To mold the hood hood 1 using the molding die 101, first, as shown in FIG. 6, the first movable die 105 is brought close to the fixed die 103 and the molding die 101 is closed. In this closed state, a cavity 109 for molding the outer resin layer 11 is formed between the molding surface 103b of the fixed mold 103 and the molding surface 105b of the first movable mold 105.

  Next, a thermoplastic resin R1 (for example, polypropylene) for molding the outer surface resin layer 11 is injected and filled into the cavity 109 from an injection machine (not shown) through a gate (not shown). FIG. 6 shows this injection filling state.

  Thereafter, the thermoplastic resin R1 is solidified in the cavity 109, and the outer resin layer 11 is molded. When the outer surface resin layer 11 is molded, the first movable mold 105 is moved to the second movable state with the outer surface resin layer 11 left on the fixed mold 103 as shown in FIGS. 7 (a) and 7 (b). Replace with mold 107. That is, the mold 101 is opened to move the first movable mold 105 away from the fixed mold 103, and the second movable mold 107 is moved closer to the fixed mold 103 instead of the first movable mold 105 to mold the mold 101. Close. At this time, the fastening member 5 is held in advance by the holding recess in the fixed core die 111 of the second movable die 107, and the fastening member 5 contacts the outer surface resin layer 11. In the initial stage of the mold closing state, the movable core mold 113 is positioned at the first position, and the second groove 113c is fixed by the joint of the convex part 111c of the fixed core mold 111 and the concave part 113b of the movable core mold 113. A cavity 115 for molding the base resin layer 13 is formed between the molding surfaces 111b and 113a of the second movable mold 107 and the back surface of the outer resin layer 11 formed continuously with the first groove 111a of the mold 111. Is done.

  Subsequently, a thermoplastic resin R2 for molding the base resin layer 13 (for example, polypropylene with long glass fibers) is injected and filled into the cavity 115 from an injection machine (not shown) through a gate (not shown). 7A and 7B show this injection filling state. At this time, since the long glass fiber contained in the thermoplastic resin R2 hardly enters the narrow groove portion and hardly enters, the linear expansion coefficient of the rib 23 formed in the groove portion is caused by the mixing of the glass fiber. Can be prevented. The thermoplastic resin R2 for molding the base resin layer 13 is made of, for example, a chemical foaming agent that generates a gas by a chemical reaction or carbon dioxide gas and nitrogen gas such as MuCell (registered trademark) Process. It is a thermoplastic resin in which an active gas (physical foaming agent) or the like is mixed in a supercritical state.

  In the thermoplastic resin R2 injected and filled into the cavity 115, the vicinity of the back surface of the outer surface resin layer 11 and the vicinity of the molding surfaces 111b and 113a of the second movable mold 107 (the fixed core mold 111 and the movable core mold 113) are the outer surface resin. As shown in FIGS. 8 (a) and 8 (b), the solid layer 17 starts to solidify at an early stage after being cooled by the surface temperature of the layer 11 and the mold temperature of the second movable mold 107, as shown in FIGS. ', The skin layer 19' and the reinforcing rib 25 'are produced, but the solid layer 17', the skin layer 19 ', the reinforcing rib 25' and the rib are not completely solidified yet. Further, at this stage, the inner portion of the thermoplastic resin R2 that will later constitute the foam layer 21 is hardly affected by the surface temperature and mold temperature of the outer resin layer 11, and is in a highly viscous gel state.

  In the thermoplastic resin R2, the solid layer 17 ′, the skin layer 19 ′, the reinforcing rib 25 ′, and the deformation preventing ribs are formed near the surface of the outer resin layer 11 and near the molding surfaces 111b and 113a of the second movable mold 107. 9 (when the thermoplastic resin R2 is solidified), as shown in FIGS. 9A and 9B, the movable core mold 113 of the second movable mold 107 and the outer resin layer 11 The movable core mold 113 is moved back in the mold opening direction X to the second position so that the distance is equal to the thickness of the base resin layer 13, and the cavity volume is expanded to about 1.25 to 4.5 times, for example.

  As a result, the thermoplastic resin R2 that has been compressed between the outer surface resin layer 11 and the movable core mold 113 of the second movable mold 107 (the expansion is restricted) is pulled by the molding surface 113a of the movable core mold 113. Then, it expands and expands due to a gas generated by a chemical reaction in the thermoplastic resin R2 or an inert gas. At this time, the glass fiber contained in the thermoplastic resin R2 is also elastically restored by reducing the compression, and the thermoplastic resin R2 expands also by this elastic restoring force (springback phenomenon). As a result, the skin layer 19 is formed on the entire surface, and the thick panel portion 15 in which the foam layer 21 is integrally formed inside the skin layer 19 is integrally formed on the back surface of the outer resin layer 11. . At this time, the thermoplastic resin R2 in the groove portion of the movable core mold 113 is solidified as it is, and the deformation preventing rib 23 is formed on the skin layer 19 on the back surface side of the thick panel portion 15.

  On the other hand, the thermoplastic resin R2 corresponding to the rear and front attachment portions 3, 9 does not move in a state where the fixed core mold 111 presses the fastening member 5 against the outer resin layer 11, and the cavity volume does not change. Then, it is cooled by the surface temperature of the outer surface resin layer 11 and the mold temperature of the fixed core mold 111 and solidified as it is, and the thin panel portion 17 into which the fastening member 5 is inserted is molded. When the fastening member 5 is inserted, the outer surface resin layer 11 previously molded is already in a solid state, so that no sink marks are generated at locations corresponding to the fastening member 5 of the outer surface resin layer 11, and the appearance quality is impaired. Absent.

  Further, when the cavity volume is enlarged, the skin layer 19 ′ that has started to solidify quickly in the vicinity of the boundary between the fixed core mold 111 and the movable core mold 113 is stretched, and the thermoplastic resin R2 in the vicinity of the skin layer 19 ′ is stretched. When the expansion due to foaming is hindered, there is an Ardare phenomenon in the corner portion continuous to the step portion 15a of the thick panel portion 15, but the thick panel portion 15 and the step portion 15a are not formed with a gap. A reinforcing rib 25 can be formed across the thin panel portion 17.

  That is, the thermoplastic resin R2 in the second groove 113c formed by the joint of the convex portion 111c of the fixed core mold 111 and the concave portion 113b of the movable core mold 113 is solidified as it is without being influenced by the expansion of the cavity volume. Thus, the reinforcing rib 25 continuous with the thin panel portion 17 side can be formed on the thick panel portion 15 side so as to straddle the stepped portion, and the reinforcing rib 25 can be sandwiched from both sides by the thick panel portion 15. . Accordingly, the reinforcing ribs 25 can be formed with a sufficient area and securely connected to the thick panel portion 15, and the reinforcing ribs 25 effective for reinforcing the thin panel portion 17 can be formed.

  As described above, the hood hood 1 can be formed. After that, the mold 101 is opened, the second movable mold 107 is separated from the fixed mold 103, the bonnet hood 1 is removed from the fixed mold 103, and finally remains on the gate of the mold 101 and solidifies. Then, the gate residual solidified material adhering to the bonnet hood 1 is cut out to obtain the bonnet hood 1.

  In the bonnet hood 1 thus obtained, the reinforcing ribs 25 formed across the thick panel portion 15 and the thin panel portion 17 are projected on the surface of the thin panel portion 17 and the thick panel portion. 15, by being cut into the stepped portion 15 a and fusing with the skin layer 19, the thin-walled panel portion 17 is strengthened by the reinforcing rib 25 because the portion cut into the thick-walled panel portion 15 is firmly held. The rigidity of the can be reliably increased.

  In the present embodiment, the hood hood 1 provided with the outer surface resin layer 11 has been described. However, the outer surface resin layer 11 does not necessarily have to be provided, and the hood hood 1 is composed of only the base resin layer 13. It doesn't matter.

  In the present embodiment, the reinforcing rib 25 has the same height as the stepped portion 15a of the thick panel portion 15. However, the present invention is not limited to this, and the reinforcing rib 25 is higher than the stepped portion 15a. Alternatively, it may be low. That is, when the movable core mold 113 is moved backward in the mold opening direction X, the second groove 113c constituting surface of the convex portion 111c of the fixed core mold 111 and the molding surface 113a of the movable core mold 113 are not necessarily flush with each other. It may not be positioned, and one of the forming surface 113a of the second groove 113c of the convex portion 111c and the forming surface 113a of the movable core mold 113 may be positioned on the fixed mold 103 side with respect to the other.

  Further, the convex portion 111c of the fixed core mold 111 is projected so as to be adjacent to the open portion of the first groove portion 111a facing the movable core mold 113, but corresponds to the open portion of the first groove portion 111a. As long as it is a place to perform, it may be provided protruding from the open position of the first groove 111a.

  In the present embodiment, when the fixed core mold 111 and the movable core mold 113 of the second movable mold 107 are positioned at the first position in the initial stage in the mold closed state, the molding surfaces 111b and 113a are positioned flush with each other. However, the present invention is not limited to this, and in the first position of the initial stage, one of the molding surfaces 111b and 113a of the fixed core mold 111 and the movable core mold 113 may be positioned on the fixed mold 103 side with respect to the other. .

  In the present embodiment, the thickness of the convex portion 111c of the fixed core mold 111 is equal to the width of the first groove portion 111a. However, the present invention is not limited to this, and the thickness of the convex portion 111c is not limited thereto. May be larger or smaller than the width of the first groove 111a. That is, the thickness of the reinforcing rib 25 may be different between the thick panel portion 15 side and the thin panel portion 17 side.

  Further, in the present embodiment, the deformation preventing ribs 23 are formed in a frame shape and a lattice shape in the frame, and the lattice shape here is a linear body extending in a diagonal direction with respect to the front-rear direction. The ribs 23 may have a lattice shape extending in the front-rear direction and the left-right direction, or may be formed in another net shape such as a honeycomb shape. . Moreover, the said rib 23 does not necessarily need to be formed.

  In the present embodiment, the base resin layer 13 includes long fibers, and a thermoplastic resin containing glass long fibers is exemplified as the thermoplastic resin R2 for molding the base resin layer 13. The resin layer 13 does not necessarily include long fibers.

  In addition, in the present embodiment, the first movable mold 105 is replaced with the second movable mold 107 while the outer surface resin layer 11 remains in the fixed mold 103, and the base resin layer 13 is formed on the back surface of the outer surface resin layer 11. However, a separately molded outer surface resin layer 11 may be prepared and set on the fixed mold 103, and the base resin layer 13 may be formed on the back surface of the outer surface resin layer 11.

  As mentioned above, although the case where this invention was applied to the bonnet food | hood was illustrated in the said embodiment, this invention is also applied to other exterior resin panels, such as a fender panel and a rear side panel, a pillar trim, a door trim, and an instrument. It can also be applied to automotive interior resin panels such as panels, and to engine covers and door module panels. In addition, those skilled in the art will understand that the above-described embodiment is an example, and that various modifications can be made to combinations of the respective constituent elements and processing processes, and such modifications are within the scope of the present invention. It is where it is done.

  As described above, the present invention is useful for a foamed resin panel such as a bonnet hood having a thin panel part and a thick panel part, and is particularly suitable for a foamed resin panel in which sufficient rigidity is required for the thin panel part. ing.

R, R1, R2 Thermoplastic resin 1 Bonnet hood (foamed resin panel)
15 Thick panel 15a Step 17 Thin panel 19 Skin layer 21 Foam layer 25 Reinforcement rib 101 Mold 103 Fixed mold (second mold)
107 Second movable type (first type)
111 Fixed core mold 111a First groove part 111c Convex part 113 Movable core mold 113b Concave part 113c Second groove part 115 Cavity for base resin layer molding

Claims (2)

A thick panel portion in which a skin layer made of a solid layer is formed on the surface and a foam layer having a resin density lower than that of the skin layer is integrally formed therein;
A thin panel portion formed of a solid layer formed integrally with the skin layer at the time of molding the thick panel portion adjacent to the thick panel portion;
A foamed resin panel in which a stepped part made of the skin layer is formed in the thickness direction at the boundary between the thick panel part and the thin panel part,
The thick panel portion and the thin panel portion are integrally formed so that reinforcing ribs straddle the stepped portion,
The foamed resin panel, wherein the reinforcing rib protrudes from the surface on the thin panel portion side and bites into the thick panel portion on the thick panel portion side to be fused with the skin layer. A mold for molding the foamed resin panel according to claim 1,
A first mold for molding one panel surface side of the foamed resin panel;
A second mold that is disposed opposite the first mold and in which a cavity for molding the foamed resin panel is formed between the first mold,
The first mold is disposed so as to correspond to the thin panel portion and the thick core portion adjacent to the fixed core mold, and is injected and filled with a thermoplastic resin. And a movable core mold that is movable from the first position to a second position corresponding to the thickness of the thick panel portion, with the position of the initial molding surface as the first position.
In the fixed core mold, a first groove for forming the thin panel portion side of the reinforcing rib is formed so as to open to the movable core mold facing side and the second mold side, and the movable core of the fixed core mold On the mold facing side, the convex portion is projected so as to correspond to the open portion on the movable core mold facing side in the first groove portion,
The movable core mold is formed such that a concave section into which the convex section is slidably fitted in the moving direction of the anti-movable core mold opens to the fixed core mold facing side and the second mold side,
The movable core mold is located at the first position, and is connected to the thick groove panel side of the reinforcing rib continuously with the first groove section by jointing the convex section and the concave section of the fixed core mold. From this state, the movable core mold is moved to the second position to expand the cavity volume, thereby foaming the thermoplastic resin in the cavity corresponding to the movable core mold. A mold for a foamed resin panel, which is structured as described above.

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