JPH0339321Y2 - - Google Patents

Description

[Detailed explanation of the idea]

[Industrial Application Field] The present invention relates to a synthetic resin bumper that is lightweight and has improved rigidity and impact resistance. [Prior art and its problems] Conventionally, most automobile bumpers have been made of metal, which has had the disadvantage of being heavy. Therefore, in recent years, studies have been actively conducted to manufacture bumpers from synthetic resin in order to reduce their weight and to put them into practical use. The purpose of using plastic bumpers is directly to reduce weight, but it is also expected to improve functionality over metal bumpers. Most of these synthetic resin bumpers are made by injection molding, and their rigidity and ability to absorb impact energy are insufficient. For example, even with a steel reinforcement, they can only provide a certain amount of impact strength, and The drawback was that the mold cost was high. On the other hand, with blow molding, it is easy to create a box-shaped item from the beginning, and specifically, with parts that have been split blow molded and joined together, or with integral blow molding, the ribs are only partially formed. There are hollow structures that can be used. Separate blow molding reduces strength due to the joints and increases costs due to the use of multiple molds, while integral blow molding is a hollow body with ribs only in one part, so it is more expensive than injection molding. Although the performance was good, the rigidity and shock absorption ability were still insufficient. The purpose of the present invention is to provide a synthetic resin bumper with a simple structure that eliminates the disadvantages of the conventional example, further increases impact strength while taking advantage of the advantages of blow molding, and at the same time allows for a streamlined mounting method. [Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention is a blow-molded synthetic resin bumper having a recess in the longitudinal direction of the back surface. The gist of this method is to embed the edges of the plates and attach them at appropriate intervals, and to use a portion of this vertical metal plate to provide hardware for attaching to the vehicle body. [Function] According to the present invention, since it is blow molded, it is easy to create a lightweight box-shaped product from the beginning, and since it is partitioned into multiple sections by vertical metal plates, these vertical plates can effectively function as structural members. , the strength is improved, and by using the vertical plate as a mounting member, rationalization such as simplifying the mounting process and reducing the number of parts can be realized. [Embodiments] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Fig. 1 is a plan view showing an embodiment of the synthetic resin bumper of the present invention, Fig. 2 is a rear view of the same, and Fig. 3 is a sectional view taken along line A-A in Fig. 1. Bumper 1 is blow molded. It is made of a hollow body and is composed of a combination of an outer plate 2 and a rib 4 whose back surface projects inward and forms a recess 3 in the longitudinal direction. Reference numeral 5 denotes a bumper side, which is a protrusion formed by bending both ends of the outer plate 2 significantly backward, and the recess 3 is present between the bumper sides 5 . Note that the shape of the rib 4 is not limited to this, and it is also possible to have a more complicated shape or to provide it on the front surface. As the synthetic resin constituting each part of the bumper, a polyolefin resin capable of large-sized blow molding, such as high-density polyethylene, polypropylene, or a mixture thereof, is used. For high density polyethylene, MI is 0.5
[g/10min] or less homopolymers or copolymers with α-olefins such as butene-1 and hexene-1 are used. For polypropylene, MFRI [g/
10 min] or less, it is preferable to use an ethylene/propylene block copolymer in terms of cold resistance. In addition, various elastomers (e.g.
(EPM, EPDM, EVA, EEA, etc.) and low-density polyethylene, and various fillers (mica,
A mixture of inorganic fillers such as talc, glass fiber, shirasu balloons, and charcoal, wood flour, and waste paper may also be used. An example using the mixed material described below is shown. - High-density polyethylene MI 0.04 70wt% - Polypropylene MFR 0.5 20wt% (Mooney viscosity 70%) - EPR 10wt% (C ₂ = content 73%) In order to further improve the strength, bumper 1
The hollow space may be filled with a foam filler such as polyurethane. 5 and 6 show a metal vertical plate 6 to be attached to the bumper 1. As an example, a steel plate with a thickness of about 0.5 mm to 1 mm is used, and at least the front, upper and lower three sides of the plate are shown. is similar to the recess 3 formed by the rib 4, and is made slightly larger than this. In addition, a locking groove 7 is formed by an undercut in parallel to the vertical edge of the vertical plate 6, and in some cases, a bolt hole 8 for connecting a mounting hardware 10, which will be described later, is formed in the center of the vertical plate 6. I let it penetrate. Note that a protruding strip may be formed instead of the locking groove 7. The vertical metal plates 6 are arranged at appropriate intervals and attached to the bumper 1 so as to divide the recess 3 into a plurality of sections. Buried. Further, a vertical plate 6 near the bumper side 5 is selected, and a mounting hardware 10 to the vehicle body 11 is fixed to this vertical plate 6 through bolt holes 8 using bolts and nuts 9. Note that the mounting hardware 10 may be formed integrally with the vertical plate 6. Next, to briefly explain the manufacturing method of the bumper 1, FIG. 7 is an explanatory diagram showing a mold for blow molding. The insertion portion 13 of the bumper 1 is formed in advance, the vertical plate 6 is placed inside the male die 12b, and the bumper 1 is removed from the mold while being left in place during blow molding, so that the bumper 1 can be attached all at once. In the bumper 1 formed in this manner, the vertical plate 6 acts as a strength structural member, and the same effect can be obtained as if the whole was divided into compartments and reinforced by metal walls. Furthermore, the point where the impact is most severe is at the attachment point to the vehicle body, and since the vertical plate 6 is located here, it acts more effectively. As mentioned above, the restraint force acts upon collision with the vertical plate 6, which not only helps to suppress the deformation as much as possible without spreading. If this width is not kept constant, the product value will decrease.Also, when an impact is applied, the upper and lower sides will expand, but the vertical plate 6 It is possible to form a bumper of a constant width by preventing dimensional changes between the two. As a specific example, a large blow molding machine [manufactured by Ishikawajima Harima Heavy Industries Co., Ltd., IPB-200c (product name)] was used to mold a passenger car bumper (weighing 2 kg) with a length of 1.6 m and a width of 0.15 m. Two types of samples were created, one with the metal vertical plate 6 (steel thickness 0.5 mm) of the present invention and one without. This bumper sample was attached to a simulated car body, and a pendulum impact test was conducted. When the pendulum is collided with the pendulum at speeds of 2.5 MPH (miles per hour) (approximately 4.0 km/h) and 5 MPH (approximately 8.0 km/h), the maximum displacement of the sample is read, and at the same time, the maximum displacement of the sample itself is measured. The circumstances of the damage were investigated. As a result, it was found that the bumper sample according to the present invention could sufficiently withstand a collision strength of 5 MPH, as shown in Table 1 below.

【table】

[Effect of idea]

As mentioned above, the synthetic resin bumper of the present invention can increase the crash strength by almost twice as much while taking full advantage of the advantage of blow molding, which allows for the production of lightweight, box-shaped items at low cost. It can be easily manufactured in a process, and the formation of the attachment part to the vehicle body can also be streamlined.

[Brief explanation of drawings]

Fig. 1 is a plan view showing an embodiment of the synthetic resin bumper of the present invention, Fig. 2 is a rear view of the same, Fig. 3 is a sectional view taken along line A-A in Fig. 1, and Fig. 4 is a vertical metal plate. 5 is an enlarged perspective view of the same part, and FIG. 6 is an explanatory view of a mold used in blow molding. 1...bumper, 2...outer plate, 3...recess,
4... Rib, 5... Bumper side, 6... Metal vertical plate, 6a... End edge, 7... Locking groove, 8...
Bolt hole, 9...Bolt, nut, 10...Mounting hardware, 11...Vehicle body, 12a...Female type, 12b...
...Male type, 13...Insertion part.

Claims (1)

[Scope of utility model registration request] In a synthetic resin bumper that is blow-molded and has a recess in the longitudinal direction of the back surface, vertical metal plates are installed at appropriate intervals by burying their edges so as to partition the recess into a plurality of parts. A synthetic resin bumper characterized by using a part of the bumper to provide mounting hardware to the vehicle body.