JPH0628878B2 - Manufacturing method of plastic coated parts - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION I. FIELD OF THE INVENTION The present invention relates to a method of manufacturing a plastic part such that a plastic overcoat is mechanically secured onto a thermoplastic polymer resin base material, in particular a polystyrene base molded to a part of the required shape. A low pressure injection molding method.

II. Description of the Prior Art As the demand for lighter vehicle weight in order to improve vehicle functionality and save fuel, more and more of the vehicle components are made of lightweight plastics. ing. Moreover, the inherent properties of plastics make them suitable for molding decorative and functional parts of motor vehicles. Wheel covers, vehicle dams and spoilers, dashboards, etc. are examples of parts that were conventionally molded from plastic. However, thin plastic parts tend to bend and thus require an internal support structure, which is usually made by the addition of metal support structures. In this case, the decorativeness of the plastic parts is not impaired, but the weight and cost cannot be reduced.

In addition to being decorative, the plastic parts of a vehicle must also withstand the harsh conditions of the road. The wheel cover of the vehicle must remain firmly attached to the metal rim, even under the heavy stress of the road surface. Furthermore, the wheel cover must withstand the heat generated by recent disc brakes and reduce running noise. Plastic air dams and spoilers must be sufficiently flexible to oppose the forces exerted by the traveling vehicle, yet strong enough not to be damaged. In addition, the interior parts of the vehicle must retain their decorativeness and aesthetics.

Application of the Invention The present invention provides a component comprising a polystyrene base molded into the required shape and a thermoplastic plastic surface coating molded onto the base and mechanically secured so as not to separate. Overcome the drawbacks of.

The method of the present invention comprises a decorative wheel, an air dam, a spoiler,
It can be applied to various vehicle parts, including dashboards and instrument panels, as well as various parts of the marine industry. The parts generally comprise a polystyrene base molded into the general shape of the part. In the case of vehicle wheels, the polystyrene base is molded so that it can be attached to a metal rim. A plastic coating conforming to its shape is attached to this molded base. Bonding of the coating is done to "mechanically" secure the thermoplastic surface to the base. Therefore, the surface layer is firmly attached to the base that gives the component rigidity without the need for an adhesive.

The overall shape of the part is made by first molding a thermoplastic polymer resin according to the final use of the product. Implementations of such resins include G.I.
E. Developed by Plastics Co., Ltd.
There is polyphenylene ocside polystyrene sold under the trademark "ET)". This jusset resin is a high performance expandable foam bead material that can withstand high temperatures. This resin expands to fill the mold when it is molded. Following the molding of the base, a thermoplastic surface layer to prevent loss of the base material is bonded by low pressure injection molding. This thermoplastic surface layer flows around the base and mechanically secures it, so no adhesive is required. In the case of vehicle wheels, the thermoplastic material flows around the edges of the ventilation holes and engages the underlying wheel rim to secure the surface to that rim.

Other objects, features, and advantages of the present invention will be apparent from the detailed description that follows in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be more fully understood by reference to the following detailed description of the preferred embodiments of the invention shown in the accompanying drawings. Like reference numerals refer to like parts throughout the drawings.

1 is a perspective view of a vehicle wheel manufactured by using the manufacturing method of the present invention, FIG. 2 is a partial sectional perspective view of a vehicle wheel manufactured by the process of the present invention, and FIG. 3 is a manufacturing process of the present invention. 4a is a sectional view of a portion showing base formation in the manufacturing process of the present invention, and FIG. 4b is a sectional view of a portion showing surface layer forming in the manufacturing process of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1 and 2 show a vehicle wheel 10 made by the manufacturing method of the present invention. For clarity and simplicity of explanation, the invention is described herein in connection with vehicle wheel 10, but it is understood that the invention is also applicable to the manufacture of various other components including air dams, spoilers, dashboards and the like. It should be. The description of the vehicle wheel 10 will also make the configuration of other related vehicle components clear.

Wheel 10 preferably includes a recessed steel plate central rim 12 provided by the manufacturer and an integral steel plate central disc 14 for tire mounting.
The central disc 14 is provided with a plurality of bolt holes 16 and a wheel spindle hole 18, whereby the wheel 1
The 0 can be easily and removably attached to the wheel hub and attached brake assembly. In order to ventilate the brake assembly, which is prone to high heat, the central disc 14 also includes a plurality of circumferentially spaced vent holes 20. As described above, the steel plate wheel composed of the rim 12 and the disc 14 is manufactured from the viewpoint of having a required strength and a ventilation function. To give the wheel 10 some aesthetic appearance, a decorative cover 2 made by the process described below is fitted to the rim 12 and the disc 14.

The decorative cover 22 generally comprises a base material 24 which is molded into the required shape and a decorative surface layer 26 which is molded onto this base material, as described subsequently. In one preferred embodiment, the base 24 is made of a high temperature resistant thermoplastic polymer resin that resists the heat generated by the wheel 10 and its brakes. Examples of such resins include G.I. E. There is Polyphenylene Oxide Polystyrene commercially available from Plastics Co. (Pittsfield, Mass.) Under the product name of Juset Resin. This resin is manufactured as a solid beet with a diameter of 0.01 to 0.1 inches and is molded using a conventional steam press or vacuum / transfer press as described below. This resin is a high performance expandable foam bead material with high heat resistance that can be used at temperatures up to 250 ° F and densities in the range of 1.5 to 40 pounds per cubic foot. The thermoplastic surface layer 26 is molded onto the foam core 24 to be mechanically secured,
Therefore no adhesive is needed.

The surface layer 26 and the base 24 are formed so that the openings 28 corresponding to the ventilation holes 20 of the rim 12 and the bores 30 corresponding to the bolt holes 16 are formed so that necessary access can be performed. The mechanical fixing of the surface layer 26 around the base 24 and the rim 12 is performed by flowing a thermal plastic around the edges of the ventilation holes 20 as described later. A flange-shaped lip 32 is formed to rigidly attach the surface layer 26 to the steel wheel.
A lip 32 may be formed around the bolt hole 16 to further secure the fixing. This mechanical attachment eliminates the need for adhesive. In the preferred embodiment, the peripheral edge 34 of the surface layer 26 extends to the edge of the wheel. This fixation principle can be used in other components as well, such as dashboards and instrument panels, which have a plurality of spaced openings. In the case of parts without openings, the surface material is adapted to extend entirely around the base material 24 so as to completely enclose it.

3 and 4 illustrate and describe a method of manufacturing a component such as a vehicle wheel 10 which is employed here as an example. In the preferred process, a steel wheel 12 fitted with a decorative cover 22 is mounted in the tool to act as a 100 mold half. An injection mold 40 is fitted to the wheel 12 and an expandable polystyrene structural base 24 is molded 102 therebetween. Base 24
Once cured, the steel sheet wheel 12 is transferred to a second station with its foam base 24 integrally molded therewith, where the low pressure injection molding process 104 joins the thermoplastic surface layer 26. Low pressure injection molding 104 is required to prevent damage to the base 24 during molding and to fill the mold cavity with thermoplastic to form the mechanical fixture 32 through the vents 20. In order to perform accurate molding of the surface layer, a backing mold 42 is provided on the back side of the wheel 12.
Is inserted into the front side of the wheel 12 and the injection mold 4
4 are combined. The cooperation of the two mold parts 42 and 44 with the wheel 12 forms the decorative surface layer 26 on the base 24 as well as the mechanical fixings 3 to the steel wheel.
2 is made.

As described above, the present invention provides a decorative vehicle wheel having a decorative cover that is fitted so as to eliminate the retention damage found in conventional wheel covers. The component manufacturing method of the present invention enables flexible styling while maintaining low manufacturing costs. The shape of the plastic cover can be changed at will by changing the shape of the structural core. Although the method of the present invention has been described herein in connection with a decorative wheel cover, the method is intended for the manufacture of various other components, such as vehicle components such as spoilers and groundability enhancing components, and the material from which the components are made. It should be understood that it can be similarly applied to manufacture ship parts from the buoyancy of the ship. In addition, other structural foam products such as closed cell fiberboard could be used to make the base and the surface layer could be formed using a modified molding process. The above detailed description is merely for a clear understanding of the invention and is not restrictive at all. Therefore, it will be apparent to those skilled in the art that various modifications can be made without departing from the spirit of the claims.

Claims (10)

[Claims] 1. A method of manufacturing a decorative composite wheel of a vehicle having a rim for receiving a vehicle tire and a central disk for mounting a wheel, the wheel having a plurality of openings, the plurality of openings. A polystyrene resin in the form of a structural base against the first side of the disc and rim so as to maintain the exposed portion, and a thermoplastic surface into the at least one opening of the disc. Thermoplastic by low pressure injection molding to extend to engage the edge of the at least one opening to mechanically secure the surface layer to the wheel to prevent separation of the base and surface layers from the disc and rim. A method comprising the steps of bonding a surface layer to the structural base. 2. The method of claim 1, wherein the thermoplastic surface layer is molded around the edge of the opening to form a flange-shaped lip over the edge. 3. The method of claim 2, wherein the central disk comprises a plurality of vent holes and a plurality of bolt holes, and the flange-shaped lip of the surface layer is formed within the vent holes. 4. The method of claim 1, wherein the polystyrene resin forming the base is a thermoplastic plastic expandable bead resin. 5. The method of claim 4, wherein the resin is polyphenylene ocside polystyrene. 6. A rim for receiving a vehicle tire, a plurality of ventilation holes, and a plurality of bolt holes for wheel mounting.
A decorated composite wheel having a metal wheel including a central disc for mounting the composite wheel on a vehicle, the structural base being molded against a first side of the metal wheel, the base being the composite base. A structural base having a shape substantially similar to the shape of the decoration of the wheel and shaped so as to maintain the ventilation holes and the bolt holes in an exposed state; and a first side portion of the metal wheel. A surface layer overlying the base to retain the structural base, the surface layer extendingly engaged into the ventilation holes of the metal wheel to mechanically secure the surface layer to the metal wheel. To prevent the surface and the base from separating from the metal wheel by means of low pressure injection molding to bond the surface to the base so as not to damage the structural base. It is to scan the shape of the matched shape, composite wheels. 7. The composite wheel of claim 6 wherein the structural base is molded from a polyester resin made of a thermoplastic plastic inflatable beet. 8. The composite wheel of claim 6 wherein said surface layer is formed by said low pressure injection molding of a thermoplastic material. 9. A composite wheel according to claim 6, wherein said surface layer forms a flange-shaped lip around the edge of said ventilation hole of said metal wheel to mechanically secure said surface layer to said disk. 10. The composite wheel of claim 6, wherein the peripheral edge of the surface layer removably engages the edge of the rim.