JPH0133404Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a synthetic resin bumper molded by a blow molding method.

Bumpers are used for the purpose of reducing the impact transmitted to the vehicle body by absorbing as much of the external impact as possible during a collision.

Conventional bumpers have disadvantages such as being heavy and expensive because they are made of metal. Therefore, in recent years, bumpers made of synthetic resin have come into widespread use in order to reduce weight. However, most of these synthetic resin bumpers are manufactured by injection molding, and have the drawback of high costs due to high mold costs and other reasons. Furthermore, since neither metal bumpers nor synthetic resin bumpers have a shock absorbing effect by themselves, they must be constructed in combination with other parts, such as by providing a shock absorber at the rear of the bumper. Therefore, the bumper is actually an assembled structure called a bumper system consisting of several functional elements. Its elements include a bumper face, i.e., the bumper body; a support, i.e., the mounting portion for attaching the bumper system to the vehicle body;
There are at least four elements: reinforcement elements for reinforcing or increasing rigidity, and shock absorbers. Some of these elements have struts installed inside the bumper to serve as both the bumper face and the shock absorber, but their role as a shock absorber is not sufficient, and the surface of the bumper body can undergo significant deformation when subjected to impact. Sometimes.

The present invention has been made to eliminate the drawbacks of the conventional example as described above, and is provided on the rear side layer of the bumper, has a stepped step to reduce the diameter, and the bottom part is fixed to the front side layer of the bumper. It is formed by a hollow molding method with a concave part of a special shape, and by providing a special type of concave part in a specific place, it also functions as a shock absorber, and its function is sufficiently increased, making it cheaper to manufacture. The present invention provides a synthetic resin bumper that can be used in various ways.

The details of the synthetic resin bumper of the present invention will be explained below based on one embodiment shown in the drawings. 1st
The figure is a perspective view showing the appearance of an automobile equipped with the bumper 1 of the present invention. As shown in FIG. 2, this bumper 1 has, for example, one or more recesses 2 formed on the back side (vehicle body side) surface 1a of the bumper main body. Recessed portion 2 formed in this bumper 1
As shown in FIG. 3, at least one step 3 is provided to reduce the diameter, and the bottom portion thereof is fixed and integrated with the surface layer of the bumper 1. Note that 4 shown in FIG. 3 is a bolt for attaching the reinforcing plate to the bumper body.

A bumper having such a structure can be easily molded from synthetic resin by blow molding. Further, the bolts 4 for attaching the reinforcing plate can also be attached at the same time by insert molding when the bumper body is formed by the blow molding method. Therefore, the bolt shown in FIG. 3 can also be formed very easily.

The shape of the concave portion provided with the step 3 formed in the bumper of the present invention is not limited to that shown in FIG. 3, and other embodiments having various shapes as described below can be considered.

FIG. 4 is a diagram showing another second embodiment in which the shape of the recessed portion is different. In this embodiment, the bottom portion has a concave portion integrated with the surface side layer having several steps to reduce its diameter, thereby further increasing the action of the shock absorber.

FIG. 5 also shows a third embodiment in which the shape of the recessed portion is different. In this embodiment, the recessed portion has a rectangular shape as shown in the figure.

As shown in the embodiments shown in the cross-sectional views of FIGS. 3 and 4, the bottom of the recess and the front wall of the bumper body are joined to form an integral structure.

It is not clear why the bumper with the structure according to the present invention exhibits its function, but the impact force received from the front layer is directly transmitted to the back side through the fixed part at the bottom of the recess, and the back side has a stepped structure. This is thought to be due to the fact that stress concentration is avoided and the cushioning properties of the step structure work.

The material constituting the bumper of the present invention may be high-density polyethylene or impact-resistant polypropylene, but other synthetic resin materials may also be used.
Among synthetic resin materials, polypropylene turns white when subjected to impact. Also, even high-density polyethylene will whiten to some extent when subjected to impact. However, when an impact is received, the impact force is relatively concentrated on the step of the recess formed in the bumper body, so only the step becomes white and the other parts do not turn white.

Further, in each embodiment, the recessed portion is formed on the back side of the bumper body, but it may be formed on the front side. However, from the viewpoint of shock absorption and appearance, the rear side is preferable. Particularly, as mentioned above, even if the bumper receives an impact and the stepped part of the recess becomes white, the appearance will not be impaired if the recess is located on the rear side. Therefore, there is no problem even if a material such as polypropylene, which easily whitens when subjected to impact, is used.

The bumper surface may be painted or plated. Furthermore, urethane may be injected into the hollow portion and foamed to provide a shock absorbing effect.

As explained above, the bumper of the present invention is provided on the back side, and has a stepped concave part whose diameter is reduced and the bottom part is fixed and integrated with the front layer, so that when it receives an impact, it absorbs the impact. The stage absorbs preferentially.
Therefore, the impact absorption ability of the recessed portion is increased, and the impact absorption ability of the bumper system as a whole is also increased. Furthermore, deformation of the surface of the bumper body due to impact as in the conventional example can be prevented. Furthermore, it is lightweight, can be easily manufactured by blow molding, and requires less mold cost than injection molding, so costs can be reduced compared to conventional ones.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the bumper attached to a car, FIG. 2 is a perspective view of the first embodiment of the present invention, and FIG. 3 is a longitudinal sectional view including the center of the recess of the above embodiment. FIG. 4 is a longitudinal sectional view including the center of the recessed portion of the second embodiment, and FIG. 5 is a perspective view of the third embodiment. 1... Bumper body, 2... Recessed portion, 3...
Step.

Claims (1)

[Scope of utility model registration request] A synthetic resin bumper formed by a blow molding method, characterized in that it has a concave portion provided on the rear side layer of the bumper, the diameter of which is reduced by providing steps, and whose bottom portion is fixed to the front side layer of the bumper. Made of bumper.