JPH03224851A - Synthetic resin bumper - Google Patents

Abstract

PURPOSE:To enable absorption of a slight error in shape by providing a support arm and a coupling part respectively between inner and outer members in the construction wherein the flange parts of the inner and outer members are jointed to each other. CONSTITUTION:A synthetic resin bumper 1 is so formed that the flange parts 2A and 2B of an outer member (facer) 2 having approximately inverted U-shape main section are jointed to the flange parts 3A and 3B of an inner member 3 having approximately U-shape main section, and each of the joints parts 5A and 5B is formed. In this case, the inner member 3 is provided with a support arm 3C concurrently molded and extended from its rear part to the vicinity of the upper rear end of the outer member 2 for connection thereto with the molten resin 5C of the same composition. In addition, at least one 5A of the aforesaid joint parts 5A and 5B is formed with the mutual coupling of the flange parts 2A and 3A.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a synthetic resin bumper and a method for manufacturing the same, and more specifically, the present invention relates to a bumper made of synthetic resin and a method for manufacturing the same. The present invention relates to a synthetic resin bumper that can be easily manufactured, is easy to assemble, has a good shape, is lightweight, and has excellent strength, cushioning performance, and restorability, and a method for manufacturing the same.

[Prior Art and Issues] Conventionally, synthetic resin bumpers have a fascia (outer member) made of painted polypropylene, etc., and a polyurethane foam or synthetic resin honeycomb structure arranged inside as a collision energy absorbing member. In addition, a back-up beam made of a metal or synthetic resin box or approximately U-shaped cross section is arranged as a rigid body inside the beam, or a box made entirely of FRP is usually used. there were.

However, since these conventional synthetic resin bumpers have a multi-layer structure, the structure is complicated, and there are problems in terms of productivity and cost.

Specifically, conventional synthetic resin bumpers are shown in Figure 7 (
It has a cross section as shown in FIG. 8 (described in Japanese Utility Model Publication No. 63-19375).

The structure shown in Figure 7 appears to be simple at first glance, but the manufacturing process involves molding the outer and inner members separately, overlapping them, and vibration welding the joint 50.50, so the problem is that the cycle time is long. In addition, product bumpers lack rigidity, so they tend to sag due to gravity or even a light collision, and if the collision energy is large, they cannot support the bumper and tend to buckle, resulting in problems with restorability.

On the other hand, the one shown in Figure 8 does not sag, but has a four-layer structure, which is complex and has a large number of parts.It takes a long cycle time to assemble parts and tighten bolts, which not only causes poor productivity, but also reduces the quality of the product. If the box-shaped body 60 made of a thin steel plate or FRP is crushed by a strong impact or mist, it can no longer be reused, and therefore has a problem of poor restorability.

Therefore, the inventors of the present invention came up with the idea of manufacturing a synthetic resin bumper using the mold sliding method (Japanese Patent Application Laid-Open No. 62-87315), which one of the inventors had already proposed, and as a result of intensive research and improvement. The present invention has now been completed.

[Objective of the Invention] The object of the present invention is to provide a lightweight and appropriate strength (absorption of collision energy, cushioning and restorability), a high degree of freedom in design in terms of aesthetics and aerodynamic properties, and easy assembly. The objective is to provide a synthetic resin bumper with a good shape and excellent mass production.

Another object of the present invention is to provide a synthetic resin bumper that is easy to assemble and can prevent cracking and deformation of the upper part of the outer member.

[Structure of the Invention] According to the present invention, there is provided a synthetic resin bumper in which an outer member having a substantially U-shaped cross section and an inner member having a substantially U-shaped cross section facing oppositely to the outer member are fixed to each other. It has a supporting arm that is molded at the same time as the inner member itself and extends from the rear part to the vicinity of the upper rear end of the outer member and is joined thereto, and at least one of the front ends of the inner member is fitted and fixed to the inner surface of the outer member. A synthetic resin bumper is provided.

The present invention will be described in detail below using examples.

[Example] Figures 1 and 2 are cross-sectional views of Example 1 and 2 of the present invention (5th
(I-I', n-II' sectional views) in the figure.

Further, FIGS. 3 and 4 are sectional views of main parts showing other embodiments of the support arm tip joint portion. FIG. 5 is a partially sectional front view of the embodiment, and FIG. 6 is a plan view thereof.

1st. 2. 3. 4. 5. In FIG. 6, 1 is a synthetic resin bumper common to Embodiments 1 and 2 of the present invention, and 2 is an outer member (fascia), the main cross section of which has an inverted U-shape. 3 is an inner member whose main cross section is U-shaped. However, the inside of the inner member 3 is reinforced by vertical ribs 6A and horizontal ribs 6B that are orthogonal to each other. Reference numeral 4 denotes a skirt portion, which is integrally formed with the outer member.

8 is an air intake port into the engine room. bumper 1
is the inner flange part (fitting female part) 2A of the outer member 2,
2A and the flange portion 3A of the inner member 3 are fixed where they fit together, and the flange portion 2B of the outer member 2
Where the flange portion 3B of the inner member 3 overlaps, they are fused (joined) with a molten synthetic resin having the same composition as the inner member and the outer member (hereinafter referred to as molten resin).

These are the joint portions 5A and 5B. Note that the joint part (fitting part) 5A may be further joined to the middle horizontal rib 6B with a certain expansion and contraction margin in the front and rear, or the joint part (fusion part)
It can also be replaced with 5B. However, when the joint part 5B is used as the fitting part 5A, it may be necessary to separately provide the joint part 5B.

Further, 3C is a support arm that is molded at the same time as the inner member and extends from the rear part to near the rear end of the upper part of the outer member.

This support arm 3C is fused (joined) to the outer member 2 using a resin supplied in the secondary injection and having the same composition as the primary injection. Note that this joint may be as shown in FIG. 3 or 4.

Numeral 9 is a void which provides an initial cushioning effect when a collision load is applied to the bumper in the direction of the arrow. When the collision load becomes larger than a certain value, the ribs 6A and 6B are distorted to support the load. The inner member 3 is strongly connected to the body or chassis and supported by two stayers from behind. The feature of the bumper of the present invention is that the slightly thick outer member and the inner member, which are integrally molded as described above, are made of synthetic resin 5 of the same composition at the internal polymerization or contact portion.
B and 5C are fused together to form a strong buffer member as a whole. The bumper of the present invention has a structure in which the collision load is elastically supported by the ribs 6A, 6B of the inner member (these may have a honeycomb structure).
If necessary, a synthetic resin foam such as expanded polystyrene or expanded polyurethane can be injected and foamed into the gap defined by 3 to form a part of the collision energy absorber for further reinforcement.

In addition, the rib 13 is the inner member 3 in the case of FIG. 1 and FIG.
Although it is molded simultaneously at the time of molding, its upper part may be fixed to the upper surface 2A of the outer member 2. This also applies to the case of FIG. And at that time, rib 1
3 may be molded at the same time during the primary injection (injection for molding the inner member and outer member), or the joint portion 5B
, 5C may be molded at the same time (secondary injection stage).

These embodiments of the present invention are manufactured by the so-called mold sliding method. That is, there is a step of molding the outer member 2 and the inner member 3 by primary injection in a pair of opposing molds, a fixed mold and a movable mold, and a step of molding the outer member 2 and the inner member 3 by leaving them in their respective female molds. The process of opening, the process of sliding the movable mold to overlap or abut the two parts and clamping the molds, and the secondary injection of synthetic resin of the same composition between the two parts join the two parts and create the necessary material. It is manufactured by adding a reinforcing member accordingly.

It is preferable that the secondary injection resin has the same composition as the primary injection resin, but the composition may not necessarily be the same, and resins with different compositions may be used as long as the fusion bonding performance is sufficient.

[Effects of the Invention] The present invention provides a lightweight and moderate strength (absorption of collision energy, cushioning and restoring properties), high degree of freedom in design in terms of aesthetics and aerodynamic properties, and easy assembly and shape. A synthetic resin bumper that is easy to mass-produce is provided. There is also the advantage that the gate can be easily set. Note that the reason why the shape is improved is that a slight shape error can be absorbed in the fitting portion 5A, and it is possible to prevent the upper part of the outer member from being bent or deformed.

[Brief explanation of drawings]

1 and 2 are cross-sectional views (II' and II-n' cross-sectional views in FIG. 5) of Examples 1 and 2 of the present invention, respectively. Moreover, FIGS. 3 and 4 are main part sectional views showing other embodiments of the distal end joint. FIG. 5 is a partially sectional front view of the embodiment, and FIG. 6 is a plan view thereof. 7 and 8 are both sectional views of the conventional example. 1 Synthetic resin bumper 2 Outer member, 3 Inner member, 2A,
2B, 3A, 3B flange part, 4
Skirt part, 5A, 5B, 5C joint, 3C support arm.

Claims (1)

[Claims] (1) In a synthetic resin bumper in which an outer member with a substantially U-shaped cross section and an inner member with a substantially U-shaped cross section facing oppositely to the outer member are fixed, the inner member is molded at the same time as itself, and then A synthetic resin bumper having a support arm extending from the rear end of the outer member to the vicinity of the rear end of the upper part of the outer member and having at least one front end of the inner member fitted and fixed to the inner surface of the outer member. .