JPH04173115A - Manufacture of vehicular fiber reinforced resin panel - Google Patents

Abstract

PURPOSE:To obtain fiber reinforced resin panel, which realize effective crush at crash and the performance of which is stabilized, by a method wherein SMC's are laminated under a condition where a space part is provided at the position, at which a weak part is to be formed in a product, of a lower mold, and, after mold clamping, heated and compressed so as to fill up the space part with SMC. CONSTITUTION:SMC's 1-4 having a predetermined property are laminated onto the mold surface 9 of the lower mold 6 of heated forming molds. In this case, SMC 1 and SMC 2 are supplied by one sheet per ply, while SMC in the lowermost ply is divided by SMC 3 and SMC 4 under a condition where a straight space part 10 is provided between SMC's 3 and 4. Further, SMC's 3 and 4 are supplied in such a manner that the middle part of the space part 10 corresponds to the crush bead in a product. Next, molds are clamped together by lowering the upper mold 5 so as to heat an compress the SMC's in order to form a hood 7. At the time, mainly SMC 3 and SMC 4 flow in the space part 10, resulting in formation of a weld 8 at the middle of the space part 10. Although the weld 8 has no problem in appearance but is weak in mechanical strength, especially in impact resistance, and thereby the weld 8 can act as the same role as the crush bead.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for manufacturing a fiber reinforced resin panel for a vehicle, and more particularly to a method for manufacturing a fiber-reinforced resin panel for a vehicle, and more specifically, a method for manufacturing a fiber reinforced resin panel for a vehicle, and more specifically, a method for manufacturing a vehicle panel made of fiber reinforced resin. The present invention relates to a method for manufacturing a fiber-reinforced resin panel for industrial use.

[Conventional technology]

In recent years, synthetic resins such as fiber-reinforced resins have been used for the outer panels of automobiles. Synthetic resin outer panels improve corrosion resistance, reduce mold costs and shorten mold production time, are lighter -111°C, can be molded into complex shapes, strengthen resistance to light collisions, and reduce vibration and noise. It is effective for such things.

When such an outer panel is a hood such as a front hood, engine hood, or trunk lid, there are two types of hoods: a two-piece hood consisting of an inner panel and an outer panel, and a one-piece hood consisting of a single plate. There are different types.

The various types of hoods described above are usually molded using SM'C (sheet molding compound), BMC (bulk molding compound), GFRP (glass fiber reinforced plastic), or the like. In particular, S.M.C.
can be conveniently used for forming hoods of various sizes and shapes.

Incidentally, the hood of an automobile, such as the front hood, needs to be crushed so as to effectively absorb the collision load in the event of a collision.

As a method of imparting such a function to a hood, a method has been proposed in which a notch, a through hole, or a thin wall portion is formed in a rib provided in the hood, and a method in which a thin wall portion is formed in a panel constituting the hood. (Utility Model Application No. 62-13782, 6
No. 4-2676, No. 63-102579.

63-107283).

Although the above method uses mechanical deformation, a method using material change has also been proposed.

For example, Japanese Utility Model Application Publication No. 64-19580 discloses a fiber-reinforced resin panel for vehicles in which the content of reinforcing fibers is lower than in other parts (thus forming weak parts). According to this method, The appearance of the weakened part is almost the same as the appearance of other parts.

[Problem to be solved by the invention]

The fiber-reinforced resin panel for vehicles disclosed in Japanese Utility Model Publication No. 19580/1980 has the following problems when laminating SMC on the mold surface:
Low-strength SMC with a lower content of reinforcing fibers than other parts is laminated in the part where the fragile part is to be formed in the product, and then the laminated SMC is heated and heated using a second mold and an upper mold.
Compress and shape. However, according to the above method, it is necessary to prepare an SMC of a different type and shape from the SMC of the main body, which increases the types of SMCs to be handled and the number of SMC cutting machines, making the molding process complicated. In addition, when forming the fragile part in a predetermined shape, for example, a straight line, an elongated low-strength SM is used.
Although it is necessary to place C in a straight line on the mold surface, in reality it is very difficult to accurately place a long and thin SMC on a predetermined portion, and there is a very high possibility that it will meander.

When such meandering occurs, variations occur in the flow state of low-strength SMC during molding depending on the degree of meandering, and the position of the weak part formed in the product becomes unstable, making it difficult to produce a product of constant quality. difficult to obtain. Furthermore, since the fragile portion formed in the product has a width greater than the width of the low-strength SMC (for example, 20 to 100 mm), it is difficult to obtain a stable crash during a vehicle collision.

The present invention is intended to solve the problems of the prior art. An object of the present invention is to provide a method for easily producing a fiber-reinforced resin panel for vehicles that can be effectively crushed during a vehicle collision and has stable performance.

[Means to solve the problem]

The method for manufacturing a fiber-reinforced resin panel for vehicles of the present invention includes, when laminating SMC on the mold surface of a lower mold, providing a space in the part where a fragile part is to be formed in the product and laminating SMC, The stacked SMC is then heated and compressed using an upper mold and a lower mold to form a panel in which the space is also filled with SMC.

The SMC that can be used in the method of the present invention is a conventional SMC.
The MC may be, for example, a resin paste made by mixing an unsaturated polyester resin with a filler, a catalyst, a thickener, etc., in which glass fibers are dispersed and a non-adhesive film is attached.

Also, 1. A conventional mold such as a molding die can also be used as the mold consisting of the mold and the mold 1.

The size, shape, material, number, etc. of the SMCs to be laminated are appropriately selected depending on the properties of the intended product.

A space is provided in a part of the product where a fragile part is to be formed, for example, by placing two SMCs with a predetermined gap between them. The width of this gap is usually about 5 to 20 mm. The space is preferably provided at a surface or near the surface of the product.

The conditions for heating and compressing the SMC are appropriately selected so that a predetermined panel filled with SMC is formed even in the space.

[Effect]

When the stacked SMC is heated and compressed using a mold and a lower mold, the spaces are also filled with SMC. Since the resin mixture mainly flows into the space from the SMCs on both sides, a linear weld portion is formed in the center of the space. Since the glass fibers hardly penetrate between the SMCs on both sides across this weld part, the mechanical strength, especially the impact resistance strength, of the weld part is extremely weak compared to other parts.
During a vehicle collision, cracks develop along the welds, effectively crushing the panel.

〔Example〕

The present invention will be explained in detail below.

FIG. 1 shows the step of compression molding SMC in one embodiment of the method of the present invention. FIG. 2 is a sectional view taken along line A--A in FIG. 1. A predetermined material, such as unsaturated polyester resin containing about 30% of reinforcing glass fiber, with predetermined properties of 5 MCl to 4 was heated to 140 to 150°C on the mold surface 9'' of the lower mold 6 of a molding die. layered on. On this occasion,
5MCl and SMC2 are supplied one by one, but the bottom S
MC is divided into two pieces, SMC3 and SMC4, and SMC3 and S
A linear space 10 is provided between the MCs 4, and the center of the space 10 corresponds to the crush bead portion of the product.

Next, as shown in Fig. 3, the second mold 5 is lowered and the mold is clamped.
The hood 7 is formed by heating and compressing the laminated SMC.

At this time, the space section 10 mainly includes SMC3 and 5IViC.
The SMC interest material enters from MC4, and the SMC interest material flowing in from SMC3 collides with the SMCJJ charge flowing in from MC4, and a weld portion 8 is formed at the center of both SMCs.

Next, the SMC is left under pressure for several minutes to harden, and then removed from the mold to obtain the hood 7 whose right half is shown in FIG. 4 from the center line 11. Further, FIG. 5 is a sectional view taken along line BB in FIG. 4.

The hood 7 has a linear weld part 8 formed in its center, but this weld part 8 is almost impossible to distinguish from other parts in terms of appearance, and is a problem in terms of appearance. In the weld part 8, the glass fiber connects both SMCs and hardly penetrates, so the mechanical strength is less than 1/3 of that of other parts, and it is particularly weak against impact. The impact resistance strength is 115 points higher than that of other parts. Therefore, the weld part 8 formed in a straight line
can play the same role as the crushed bead part.

〔Effect of the invention〕

The manufacturing method of a fiber-reinforced resin panel for vehicles according to the present invention is such that when laminating SMC on the mold surface, a space is provided in the part where a fragile part is to be formed in the product and SMC is laminated, and then the SMC is laminated. By heating and compressing the SMC, SMC is also applied to the space.
In order to form a panel filled with MC, a different kind of elongated S from the main body is used to form a weak part as in the conventional method.
There is no need to prepare MC, and the panel molding process can be simplified.

In addition, when panels are manufactured using conventional methods, the fragile portion has a certain width of, for example, about 20 to 100 mm, so it is difficult to obtain a notch effect when an impact is applied, and a stable crash is difficult to occur. When a panel is manufactured by the method of the present invention, the linear weld portion becomes a fragile portion, and therefore, when an impact is applied, a notch effect is likely to be obtained, and a stable crash will occur.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing a step of compression molding SMC according to an embodiment of the method for manufacturing a fiber-reinforced resin panel for vehicles of the present invention. FIG. A cross-sectional view along the line, Figure 3]
- An explanatory diagram showing a state in which the mold and the lower mold are clamped; Figure 4 is a diagram showing the right half from the center line of the hood manufactured by the method of the present invention; Figure 5 is a diagram showing the right half of the hood manufactured by the method of the present invention; FIG. In the figure, L 2,3.4-SMC 3-J-type 6/-F type 7-hood 8-weld part 9-mold surface 10-space part 11-center line

Claims (1)

[Claims] When laminating SMC (sheet molding compound) on the mold surface of the lower mold, a space is created in the part where the fragile part is to be formed in the product and SMC is laminated, and then laminated by the upper mold and the lower mold. A method for manufacturing a fiber-reinforced resin panel for a vehicle, comprising heating and compressing the SMC to form a panel in which the space is also filled with SMC.