JPH05254004A - Manufacture of synthetic resin bumper - Google Patents

Abstract

PURPOSE:To manufacture a synthetic resin bumper at low cost and with good productivity by omitting assembling process by a method wherein the bonding between a bumper beam and a bumper face is simultaneously performed with the blow molding of the bumper face. CONSTITUTION:A bumper beam 1 is installed on the head part 212a of the projecting bead 212 of the male mold of a blow molding die 2. Blow molding is performed by feeding molten polypropylene resin in a cavity 24 under the condition that molds are closed. Thus, a synthetic resin bumper, in which a hollow bumper face covers the outer surface of the bumper beam 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a synthetic resin bumper which is integrally provided on a surface of a bumper beam when a bumper face is formed by blow molding.

[0002]

2. Description of the Related Art Conventional synthetic resin bumpers include, for example, Japanese Utility Model Laid-Open No. Sho 59-167053 and Japanese Utility Model Laid-Open No. Sho 63-63.
Japanese Patent No. 46262 describes a synthetic resin bumper face having a hollow portion, and Japanese Patent Laid-Open Nos. 62-240514 and 3-1914 describe a composite long fiber reinforced thermoplastic resin bumper beam. ing.

[0003]

However, as a synthetic resin bumper, a synthetic resin bumper face having a hollow portion as described above and a composite long fiber reinforced thermoplastic resin bumper beam are molded in separate steps, It assembled by connecting these with an appropriate connecting member. Therefore, since the molding process and the assembly process are separate processes,
There is a problem that the manufacturing process is complicated, the productivity is poor, and the cost is high.

The present invention solves the above-mentioned conventional problems, and the bumper beam and the bumper face are joined at the time of blow molding of the bumper face to produce a synthetic resin bumper by omitting an assembly step. It was made for the purpose of manufacturing with good performance and at low cost.

[0005]

SUMMARY OF THE INVENTION According to the present invention, a molten thermoplastic resin is supplied into a blow molding die in which a molded body of a bumper beam made of a fiber reinforced thermoplastic resin is mounted to form a bumper face by blow molding. It is a method for manufacturing a synthetic resin bumper in which a bumper face having a hollow portion is integrally provided on the surface of the bumper beam by forming (so-called hot parison method).

In the present invention, the fiber-reinforced resin thermoplastic resin used for forming the bumper beam comprises a thermoplastic resin and a reinforcing fiber which is thermally stable at the melting temperature of the thermoplastic resin.

As the thermoplastic resin, all synthetic resins which can be melted by heating can be used, and examples thereof include polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyamide, polyethylene terephthalate, polybutylene terephthalate, polycarbonate, polyvinylidene fluoride, and the like. Examples thereof include polyphenylene sulfide, polyphenylene oxide, polyether sulfone, and polyether ether ketone.

Further, copolymers, graft resins and blend resins containing the above thermoplastic resin as a main component, for example, ethylene-vinyl chloride copolymer, vinyl acetate-ethylene copolymer, vinyl acetate-vinyl chloride copolymer. Further, urethane-vinyl chloride copolymer, acrylonitrile-butadiene-styrene copolymer, acrylic acid-modified polypropylene, maleic acid-modified polyethylene and the like can also be used. Then, additives such as a stabilizer, a lubricant, a processing aid, a plasticizer, and a colorant may be blended with these thermoplastic resins.

As the reinforcing fiber, for example, glass fiber,
Carbon fiber, silicon / titanium / carbon fiber, boron fiber,
Fine metal fibers, aramid fibers, polyester fibers,
Organic fibers such as polyamide fibers are used.

The reinforcing fibers have a monofilament diameter of 1 to
It is preferably 50 μm. The length is appropriately determined depending on the required performance and shape of the bumper beam made of a fiber reinforced thermoplastic resin, but is preferably 5 mm or more. If the length is less than 5 mm, the reinforcing effect of the reinforcing fibers tends to be insufficient. Further, considering that the reinforcing fibers are filled up to the end of the bumper beam, the short fibers are preferable to the continuous fibers. If continuous fibers are difficult to form, short fibers are used as appropriate.

The addition amount of the reinforcing fiber is appropriately determined according to the required physical properties of the bumper beam to be produced, but it is preferably 5 to 70% by weight in the bumper beam. If the addition amount is less than 5% by weight, the mechanical strength of the bumper beam tends to be insufficient, and conversely, if it exceeds 70% by weight, a bumper beam uniformly impregnated with a thermoplastic resin is obtained. Tends to be difficult.

As the thermoplastic resin used for blow molding the bumper face, the same thermoplastic resin used for molding the bumper beam is used.

[0013]

According to the present invention, a molten thermoplastic resin is supplied into a blow molding die in which a molded body of a bumper beam made of a fiber reinforced thermoplastic resin is mounted to form a bumper face by blow molding. By integrally providing the bumper face having the hollow portion on the surface of the beam, the synthetic resin bumper can be manufactured with good productivity and at a low cost by omitting the assembly process.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the accompanying drawings. FIG. 1A is a perspective view showing a bumper beam used in an embodiment of the present invention, and FIG. 1B is a partially cut perspective view thereof. As a fiber reinforced thermoplastic resin, a fiber reinforced resin sheet (thickness: 3.7 mm, fiber content: 40% by weight) obtained by impregnating a swirl-shaped continuous glass roving mat with a powdered polypropylene resin (MFR: 6 g / 10 min). It was used. This fiber reinforced resin sheet, 400 ℃
After melting the polypropylene resin with the far infrared heater, pressurizing at 25 kg / cm ^{2 with} a compression molding machine,
A fiber reinforced thermoplastic resin bumper beam 1 as shown in FIG. 1 was manufactured.

The bumper beam 1 is provided with side wall portions 112 on both sides from the both side edges of the front wall portion 111 which is gently curved in the longitudinal direction to the bending direction side of the front wall portion 111, and has a substantially U-shaped cross section. An elongated box-shaped main body 11 having an opening is formed. Side flanges 12 are provided along the longitudinal direction outward from both side edges on the opening side of the main body 11.
Main part 11 Side flange part 1 from both ends on the opening side outward
2 is provided with an end collar portion 13 connected to it. Side flange 12
A bent portion 121 that is recessed toward the front wall portion 111 side is provided in the center portion of the.

FIG. 2 is a partially cutaway perspective view for explaining the state before the mold for blow molding is closed in the blow molding process of the embodiment of the present invention, and FIGS. 3 and 4 respectively. FIG. 4A is a horizontal cross-sectional view and a vertical cross-sectional view showing a state in which the blow molding die is closed in the blow molding process of the example of the present invention.

Reference numeral 2 denotes a blow molding die, which is a male die 21.
And a female mold 22. The male mold 21 is provided with an elongated ridge 212 on one surface of a base plate 211. Ridge 212
Is a head 212a for mounting the bumper beam 1.
And a shoulder portion 212b provided along one side thereof along the longitudinal direction. Head 212a is bumper beam 1
The outer surface shape corresponding to the inner surface shape of the bumper beam 1 is provided, and the protruding height thereof is slightly larger than the inner depth of the main body portion 11 of the bumper beam 1, and the bumper beam 1 is mounted on the head 212a of the ridge 212. At this time, a gap is formed between the side flange portion 12 and the end flange portion 13 of the bumper beam 1 and the surface of the shoulder portion 212b and the surface of the base plate 211. A base 213 for inserting a blow molding nozzle is provided at an upper end of the protrusion 212 of the base plate 211 at a predetermined distance from the end surface of the protrusion 212.

The female die 22 is provided with an elongated recess 221. When the gap between the concave portion 221 and the male die 21 is closed, the side surface of the concave portion 221 abuts the side surface of the shoulder 212b of the protrusion 212 of the male die 21, and the surface of the protrusion 212 of the male die 21 and the base 2
It is sized so as to be opposed to the surface of 11 at a predetermined interval. A cap 222 for inserting a blow molding nozzle is provided on the upper end side of the female die 22.

The head 21 of the protrusion 212 of the male die 21
When the bumper beam 1 is attached to 2a so that the inner surface of the bumper beam 1 is in contact with the female mold 22 and the space between the female mold 22 and the bumper beam 1 is closed,
For blow-molding a bumper face to be molded between the outer surface of the mold 21, the surface of the shoulder 212b of the protrusion 212 of the male mold 21, the surface of the base 211, and the inner surface of the recess 221 of the female mold 22. The cavity 24 is formed. Side flange portion 12 of bumper beam 1 mounted on protrusion 212 of male die 21
Also, the end flange portion 13 is in a state of being projected into the cavity 24. Base 213 of male die 21 and base 22 of female die 22
A through hole 23 through which the blow molding nozzle is inserted is formed between the two.

A blow molding nozzle (not shown) is inserted into the cavity of the closed mold through a through hole 23, and the base end portions thereof are fixed to the mouthpieces 213 and 223, and a polypropylene resin (melted by an extruder (not shown) ( MFR: 6g / 10
Min) was extruded into a tube to form a parison, and air was blown into the parison for blow molding to form a hollow bumper face. The resin bubble supplied from the blow molding nozzle to the cavity expands in a balloon shape and fills the cavity, and the inner peripheral surface bends the side flange portion 12 and the end flange portion 13 protruding into the cavity. cover.

When the mold is opened, as shown in FIG. 5, a hollow bumper face 3 is coated on the outer surface of the bumper beam 1, and the side flange portion 12 and the end flange portion 13 of the bumper beam 1 are formed on the bumper face 3. The synthetic resin bumper 4 covered so as to fit into the groove 31 formed on the inner surface was obtained.

[0022]

EFFECTS OF THE INVENTION Since the present invention has the above-described structure, the synthetic resin bumper can be manufactured with high productivity and at low cost by omitting the assembly process.

[0023]

[Brief description of drawings]

1A and 1B are explanatory views showing a bumper beam used in an embodiment of the present invention, FIG. 1A is a perspective view showing the bumper beam, and FIG. 1B is a partially cutaway perspective view showing the bumper beam.

FIG. 2 is a partially cutaway perspective view for explaining a state before the mold for blow molding is closed in the blow molding process of the embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a state where the blow molding die is closed in the blow molding process of the embodiment of the present invention.

FIG. 4 is a vertical cross-sectional view showing a state in which the blow molding die is closed in the blow molding process of the embodiment of the present invention.

FIG. 5 is a partially cutaway perspective view showing a synthetic resin bumper obtained according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Bumper beam 2 Blow molding die 3 Bumper face 4 Synthetic resin bumper 11 Body part 12 Side flange part 13 End flange part 21 Male type 22 Female type 23 Through hole 24 Cavity 31 Recessed groove 111 Front wall part 112 Side wall part 121 Bent portion 211 Base 212 Protruded strip 212a Head 212b Shoulder 213, 222 Base 221 Recess

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Claims (1)

[Claims] 1. A molten thermoplastic resin is supplied into a blow molding die in which a molded body of a bumper beam made of a fiber reinforced thermoplastic resin is mounted to form a bumper face by blow molding, thereby forming a bumper beam. A method for manufacturing a synthetic resin bumper, comprising integrally providing a bumper face having a hollow portion on the surface.