Resin member and method for manufacturing the same

Abstract

To provide a novel resin member capable of suppressing appearance defects that occur on a design surface, and a method for manufacturing the resin member.SOLUTION: A resin member includes: an extension part arranged away from a back surface of a panel part including a design surface and extending along the panel part; and a wall part extending toward the panel part from a position spaced apart from a central part in an extending direction of the extension part and connected to the panel part. The extension part includes: a gate surface including gate traces; and an opposing surface facing the gate surface with a thickness interposed therebetween.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a resin member and a method for manufacturing a resin member. [Background technology]

[0002] Resin members used as exterior parts for vehicles have been known (see, for example, Patent Document 1). The resin member of Patent Document 1 is manufactured using a direct gate injection molding die in which molten resin is directly poured into the resin member from a valve gate (called an injection unit in Patent Document 1) arranged on the rear surface of the resin member.

[0003] When a resin part is molded using such a direct gate injection mold, sink marks, which are a type of appearance defect that occurs on the design surface, may occur. To prevent such sink marks, the injection mold in Patent Document 1 has a gate block on the back surface of the resin part, and molten resin is poured through the gate block.

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-124932 Summary of the Invention [Problem to be solved by the invention]

[0005] However, it is also desirable for the direct gate method to suppress appearance defects such as cloudiness that occur due to the temperature when the molten resin near the valve gate is cooled or the speed at which the molten resin near the valve gate is supplied.

[0006] An object of the present disclosure is to provide a novel resin member that can suppress appearance defects that occur on the design surface, and a method for manufacturing a resin member. [Means for solving the problem]

[0007] The resin member according to the present disclosure includes an extension portion disposed at a distance from the rear surface of a panel portion including a design surface and extending along the panel portion, and a wall portion extending from a position spaced from a center portion of the extension portion in the extension direction toward the panel portion and connecting to the panel portion. The extension portion has a gate surface including a gate mark and an opposing surface facing the gate surface with a portion sandwiched between them.

[0008] A method for manufacturing a resin member according to the present disclosure is a method for manufacturing a resin member having a panel portion including a design surface. The method for manufacturing the resin member includes forming a cavity in a molding die to mold an extension portion that is spaced from a surface of the panel portion opposite the design surface and extends along the panel portion, and a wall portion that extends from a position spaced from a center portion in the extension direction of the extension portion toward the panel portion and connects to the panel portion, and injecting molten resin into the extension portion of the cavity.

[0009] According to this resin member and method for manufacturing the resin member, the molten resin flows into the panel portion via the wall portion located away from the center of the extension portion in the extension direction. This prevents discoloration of the resin caused by the temperature and speed of the molten resin near the valve gate from transferring to the design surface of the panel portion. As a result, poor appearance of the design surface can be prevented. [Effects of the Invention]

[0010] According to the present disclosure, it is possible to provide a novel resin member that can suppress appearance defects occurring on the design surface, and a method for manufacturing a resin member. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 4 is a rear view of the resin member according to the embodiment of the present disclosure. [Figure 2] FIG. 2 is a cross-sectional view taken along the line AA in FIG. 1. [Figure 3] 5A to 5C are diagrams illustrating a method for manufacturing a resin member according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0012] An embodiment of the present disclosure will be described below with reference to the drawings. As shown in Fig. 1, a resin member 1 includes a panel portion 2, an extension portion 4, and a wall portion 6. In this embodiment, the resin member 1 is an upper shell of a roof spoiler made of ABS resin and attached to, for example, an automobile.

[0013] While such ABS resin has excellent heat resistance, the molten resin does not flow easily compared to polypropylene, which is mainly used as a resin material for automobile bumpers, etc. For this reason, it is preferable to mold a relatively large resin member 1 made of such ABS resin using the direct gate method.

[0014] As shown in FIG. 2, the panel portion 2 has a design surface 2a and a back surface 2b. The design surface 2a is located in a position that is visible from the outside when the resin member 1 is assembled. On the other hand, the back surface 2b is located in a position that is not visible from the outside. For example, if the resin member 1 is a roof spoiler, the lower shell is fixed to the back surface of the upper shell, so the back surface 2b is not visible from the outside. The panel portion 2 is formed to a uniform thickness by an injection molding die 10, which will be described later.

[0015] The extension portions 4 are disposed at a distance from the rear surface 2b of the panel portion 2 and extend along the panel portion 2. In this embodiment, three extension portions 4 are disposed in a row in the longitudinal direction near the center of the panel portion 2 in the short side direction. However, the arrangement of the extension portions 4 may be changed as appropriate depending on the size of the panel portion 2, etc. In any case, the extension portions 4 may be disposed in a location other than the end portion of the panel portion 2. Furthermore, the extension portions 4 in this embodiment have a shape that is roughly a square plus a semicircle. The semicircle portion is formed to match the nozzle diameter of the valve gate 12, which will be described later. However, the extension portions 4 may be any size as long as they are equal to or larger than the nozzle diameter of the valve gate 12.

[0016] The extension portion 4 has a gate surface 4a and an opposing surface 4b that faces the gate surface 4a with a portion sandwiched therebetween. The gate surface 4a is the surface on which a valve gate 12 is disposed in an injection molding die 10 (described later) (see FIG. 3). Therefore, as shown in FIG. 1, the gate surface 4a of the resin member 1 after molding includes a gate mark 4c. The gate mark 4c is formed in a circular shape corresponding to the nozzle shape of the valve gate 12.

[0017] As shown enlarged in FIG. 2, the gate surface 4a extends in a direction different from the opposing surface 4b. Specifically, the gate surface 4a extends at a 90-degree angle relative to the mold removal direction described below. On the other hand, the opposing surface 4b preferably extends substantially parallel to the back surface 2b of the panel portion 2 or at an angle that opens relative to the back surface 2b so that the slide mold 18 described below can be removed. Therefore, when the panel portion 2 curves toward the extension portion 4, the gate surface 4a approaches the opposing surface 4b as the extension portion 4 moves away from the wall portion 6. In other words, the thickness of the extension portion 4 increases from the tip (the end portion on the semicircular side in this embodiment) toward the wall portion 6.

[0018] The wall portion 6 extends from a position spaced from the extension direction center portion O of the extension portion 4 toward the panel portion 2 and connects to the back surface 2b of the panel portion 2. In this embodiment, the extension direction center portion O is approximately the center of the circular shape of the gate mark 4c. In this embodiment, the wall portion 6 extends from the extension direction end portion of the extension portion 4. Specifically, the wall portion 6 extends from the extension direction end portion opposite the semicircular shape of the extension portion 4 toward the back surface 2b of the panel portion 2.

[0019] The thickness Ta of the panel portion 2 is formed to be thicker than the thickness Tb of the wall portion 6. This makes it less likely that sink marks will occur in the panel portion 2 when the molten resin in the wall portion 6 solidifies. The thickness Tc of the extension portion 4 is formed to be thicker than the thickness Tb of the wall portion 6. This makes it easier for the molten resin to flow to the wall portion 6.

[0020] Next, a method for manufacturing the resin member 1 will be described with reference to FIG.

[0021] As shown in FIG. 3(I), an injection molding die 10 for molding the resin member 1 has a valve gate 12, a movable die 14, a cavity 16, a slide die 18, and a fixed die 20. The cavity 16 has a panel portion molding portion 22 that molds the panel portion 2 of the resin member 1, an extension portion molding portion 24 that molds the extension portion 4, and a wall portion molding portion 26 that molds the wall portion 6. The valve gate 12 is attached to the extension portion molding portion 24 at a position that corresponds to the gate surface 4a of the extension portion 4. The valve gate 12 may be a general injection unit that has a hot runner and a nozzle portion provided at the tip of the hot runner.

[0022] When molten resin is poured into the extension-portion-molding portion 24 of the cavity 16 of the injection molding die 10 through the valve gate 12, the molten resin fills the extension-portion-molding portion 24 and then flows toward the wall-portion-molding portion 26. Because the thickness Tc of the extension portion 4 is greater than the thickness Tb of the wall portion 6, the molten resin easily fills the wall-portion-molding portion 26. The molten resin that passes through the wall-portion-molding portion 26 fills the portion of the cavity 16 corresponding to the panel portion 2. In this embodiment, the extension-portion-molding portion 24 and the wall-portion-molding portion 26 are provided in three locations in the panel portion-molding portion 22 of the cavity 16. This allows the molten resin to easily flow to the end of the panel portion-molding portion 22. As a result, the injection molding die 10 of this embodiment can mold a larger resin member 1. In particular, when the molten resin has a high viscosity and is difficult to flow, such as ABS resin, providing the extension portion 4 at locations other than the end of the resin member 1 makes it easier to mold a larger resin member 1.

[0023] Furthermore, the molten resin near the valve gate 12 is characterized by a high velocity (shear rate) and a high temperature. However, the cavity 16 for molding the resin member 1 of the present disclosure has the panel portion molding portion 22 and the extension portion molding portion 24 spaced apart from each other. Therefore, although the shear rate is high in the extension portion molding portion 24 of the cavity 16 and gas bubbles are likely to be generated, the shear rate decreases by the time the molten resin reaches the panel portion molding portion 22 and forms the design surface 2a of the panel portion 2. The temperature of the molten resin also decreases by the time it passes through the wall portion molding portion 26 and reaches the panel portion molding portion 22. This makes it possible to suppress appearance defects that occur on the design surface 2a due to the effects of shear rate and temperature. One example of an appearance defect that occurs on the design surface 2a due to the effects of shear rate and temperature is cloudiness, in which some of the resin appears discolored compared to the surrounding resin.

[0024] Furthermore, in the cavity 16 that molds the resin member 1 of the present disclosure, the wall portion molding portion 26 extends from the end of the extension portion molding portion 24 in the extension direction. In other words, the wall portion molding portion 26 extends from a position offset from the center of the nozzle of the valve gate 12. This ensures that the molten resin injected from the valve gate 12 always passes through the extension portion molding portion 24 before entering the wall portion molding portion 26. This inevitably reduces the temperature and speed of the molten resin. As a result, it is easier to further suppress appearance defects that occur on the design surface 2a of the panel portion 2. Furthermore, because the extension portion 4 and the wall portion 6 are located on the back surface 2b of the panel portion 2, they are not visible from the outside.

[0025] The molten resin is cooled when it is filled up to the end of the panel portion molding portion 22. At this time, as shown in Fig. 2, the panel portion molding portion 22 and the wall portion molding portion 26 are formed so that the thickness Ta of the panel portion 2 is greater than the thickness Tb of the wall portion 6, and therefore, it is possible to prevent sink marks from occurring on the design surface 2a of the panel portion 2 due to cooling of the molten resin filled in the wall portion molding portion 26.

[0026] As shown in Figure 3 (II), when the molten resin cools, the movable mold 14 is removed, revealing the design surface 2a. Thereafter, the resin member 1 is removed from the fixed mold 20. Then, as shown in Figure 3 (III), the sliding mold 18 that formed the opposing surface 4b of the extension portion 4, the back surface 2b of the panel portion 2, and the wall portion 6 is removed, and the resin member 1 is manufactured.

[0027] As described above, according to the present disclosure, it is possible to provide a novel resin member 1 and a method for manufacturing the resin member 1 that can suppress appearance defects that occur on the design surface 2a.

[0028] <Other embodiments> Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above embodiments, and various modifications are possible without departing from the spirit of the invention.

[0029] (a) In the above embodiment, the resin member 1 has been described as an automobile roof spoiler, but the present disclosure is not limited to this. The resin member 1 may be a relatively large resin molded product (for example, one with a long side length of 1 m or more and a short side length of 0.3 m or more).

[0030] (b) In the above embodiment, the resin member 1 is described as having the extension 4 and the wall 6 remaining on the rear surface 2b, but the present disclosure is not limited to this. After the resin member 1 is molded by the manufacturing method of the present disclosure, the extension 4 and the wall 6 may be cut off. [Explanation of symbols]

[0031] 1: Resin material, 2: Panel portion, 2a: Design surface, 2b: Back surface 4: Extension portion, 4a: Gate surface, 4b: Opposite surface, 4c: Gate mark 6:Wall part 10: Injection molding die, 12: Valve gate, 14: Movable die 16: Cavity, 18: Slide type, 20: Fixed type 22: Panel portion molding portion, 24: Extension portion molding portion, 26: Wall portion molding portion O: Central part in the extension direction Ta: thickness, Tb: thickness, Tc: thickness

Claims

1. an extension portion disposed apart from a rear surface of the panel portion including the design surface and extending along the panel portion; a wall portion extending from a position spaced from a center portion in the extension direction of the extension portion toward the panel portion and connected to the panel portion; Equipped with The extension portion is a resin member having a gate surface including a gate mark in the shape of a nozzle of a valve gate, and an opposing surface opposing the gate surface with a part sandwiched therebetween.

2. A plurality of extension portions are arranged at a distance from a rear surface of the panel portion including the design surface and extend along the panel portion; a plurality of wall portions corresponding to the plurality of extension portions, each of the plurality of wall portions extending from a position spaced from a center in the extension direction of the corresponding extension portion toward the panel portion and connecting to the panel portion; Equipped with Each of the plurality of extension portions is a resin member having a gate surface including a gate mark and an opposing surface opposing the gate surface with a thickness therebetween.

3. an extension portion disposed apart from a rear surface of the panel portion including the design surface and extending along the panel portion; a wall portion extending from a position spaced from a center portion in the extension direction of the extension portion toward the panel portion and connected to the panel portion; Equipped with The extension portion has a gate surface including a gate mark and an opposing surface opposing the gate surface with a material therebetween, the gate surface extends in a direction different from the opposing surface, and the opposing surface extends substantially parallel to the surface of the panel portion facing the wall portion; The resin member according to claim 1 or 2.

4. The thickness of the extension portion is formed to be greater than the thickness of the wall portion. The resin member according to claim 1 .

5. A method for manufacturing a resin member having a panel portion including a design surface, a cavity is formed in a molding die to mold an extension portion that is spaced apart from a surface of the panel portion opposite the design surface and extends along the panel portion, and a wall portion that extends from a position spaced apart from a center portion in the extension direction of the extension portion toward the panel portion and is connected to the panel portion; A method for manufacturing a resin member, comprising: injecting molten resin from a nozzle portion of a valve gate disposed facing the extension portion of the cavity.

6. A method for manufacturing a resin member having a panel portion including a design surface, a cavity is formed in a molding die to mold an extension portion that is spaced apart from a surface of the panel portion opposite the design surface and extends along the panel portion, and a wall portion that extends from a position spaced apart from a center portion in the extension direction of the extension portion toward the panel portion and is connected to the panel portion; Injecting molten resin from the extension portion of the cavity; cutting off the extension portion and the wall portion from the resin member formed from molten resin; A method for manufacturing a resin member.

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