DESC:FIELD OF INVENTION

The present invention relates to automobile bumpers. In particular, present invention relates to light-weight bumper beams for automobiles. More particularly, the present invention relates to a hybrid composite bumper beam structure for low-speed impact application in automobiles.

BACKGROUND OF THE INVENTION

In Automotive vehicles, the bumper beam is provided both in the front and rear of the vehicles.

In particular, the front bumper is configured to absorb small shocks transmitted to it, however without causing any serious damage to the critical parts such as the cooling system, hood, signalling devices in the front end of the bumper.

Similarly, the rear bumper is also configured to protect the luggage compartment or boot, from such small shocks transmitted to it. This configuration is reversed in rear-engine vehicles.

Generally, the bumper assembly is composed of a bumper beam with or without energy absorber. In the configurations without energy absorber, the bumper beam is designed to efficiently absorb the impact energy of the collisions occurring at slow-speeds. Usually, the bumper beam incudes front cross-member connecting the crash boxes at the ends and is connected to the body member by bolts. Currently, most of the bumper beams are made of aluminium or high-strength steel.

DISADVANTAGES WITH THE PRIOR ART

The present combination of materials, i.e. aluminium and high-strength steel is disadvantageous due to substantially higher weight. This combination also poses a problem in terms of corrosion of the sheet metal of these bumpers.
Therefore, there is an existing need to explore better alternate materials, which overcome the difficulties faced by the bumper beams made of such combination of materials such as aluminium and high-strength steel.

This necessitated the inventors to develop a hybrid concept for achieving improvements in terms of weight-reduction, anti-corrosion properties, capability of recycling the materials and enhanced system integration and so on.

OBJECTS OF THE INVENTION

Some of the objects of the present invention - satisfied by at least one embodiment of the present invention - are as follows:

An object of the present invention is to provide a hybrid composite bumper beam for an automotive vehicle.

Another object of the present invention is to provide a hybrid composite bumper beam which is light-weight.

Still another object of the present invention is to provide a hybrid composite bumper beam which has anti-corrosive properties.

Yet another object of the present invention is to provide a hybrid composite bumper beam which facilitates improved system integration.

A further object of the present invention is to provide a hybrid composite bumper beam, the materials of which can be (partially) recycled subsequently.

A still further object of the present invention is to provide a hybrid composite bumper beam which offers an effective crash performance.

A yet further object of the present invention is to provide a hybrid composite bumper beam, in which the front member follows the bumper-profile.
These and other objects and advantages of the present invention will become more apparent from the following description when read with the accompanying figures of drawing, which are, however, not intended to limit the scope of the present invention in any way.

SUMMARY OF THE INVENTION

In accordance with the present invention, there is provided a hybrid composite bumper beam for an automobile, wherein the bumper beam comprises:
(i) a profiled front member configured made of thermoplastic composite material;
(ii) a composite crash box assembly including a pair of shock absorbers integrated with the front member by adhesive bonding and disposed on either side of the bumper; and
(iii) a respective connecting member connected on either side of the bumper to the body member of the automobile by a plurality of fasteners;
wherein the bumper is mounted on the profiled front member by means of a respective profiled connection provided on either side thereof by using an adhesive bonding therebetween, for transferring shock energy received by the bumper during impact of the automobile at slow speeds to the body member thereof.

Typically, the crash box assembly comprises a pair of parallelly disposed straight glass fiber reinforced plastic plates connected by means of a structural adhesive to the front member at the front end thereof and to the connecting member at the rear end thereof.

Typically, the profiled front member is configured with an opening on either side thereof for connection to a respective crash box assembly.

Typically, each opening in the front member comprises an undulating curved profile bonded at the inner face of the respective crash box assembly and a curved flange at the outer face of the respective crash box assembly for adhesive bonding with a respective crash box assembly on either side of the bumper.
Typically, the curved flanges are made of thermoplastic composite material and function as shock absorbers for transferring the shock energy received by the bumper during impact of the automobile at slow speeds, via the front member, crash box assemblies and the connecting members to the body member of the automobile.

Typically, the connecting member is made L-shaped with the shorter arm thereof connected to the crash box assembly and the longer arm thereof fastened on the body member of the automobile.

Typically, the front member is made of thermoplastic glass reinforced composite and the shock absorbers are made of thermoset pultruded glass fiber reinforced plastic (GFRP) with a thermoset resin.

Typically, the front member is made of thermoplastic glass reinforced composite and the shock absorbers are made of thermoset pultruded glass fiber reinforced plastic (GFRP) with a thermoset resin.

Typically, a respective crash box assembly is connected to the front member by means of a structural adhesive.

Typically, the front member is made of a polyamide based thermoplastic composite.

Typically, the front member is manufactured by using thermo-compression moulding or injection-compression moulding process or Hot stamping process.

In accordance with the present invention, there is also provided a pultruding process for making front member of the hybrid composite bumper beam, the process comprising the steps of:
(I) Impregnating the reinforcement materials such as fibres or woven or braided strands with resin;
(II) Preforming the resin impregnated reinforcement materials to obtain the preformed front member, and
(III) Pulling the preformed front member through a heated stationary die for facilitating the polymerization of the resin impregnated therein.
Typically, the impregnation is done by pulling these reinforcement materials through a bath.

Typically, the impregnation is done by injecting the resin into an injection chamber connected to a heated stationary die.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The present invention will be briefly described with reference to the accompanying drawings, which include:

Figure 1 shows a typical construction of the hybrid composite bumper beam configured in accordance with the present invention.

Figure 2 shows a sectional representation along section A-A of the hybrid composite bumper beam of Figure 1 depicting the fixing arrangement of the front member to the absorber.

Figure 3 shows the detail ‘X’ of the fixing arrangement of the front member to the absorber.

Figure 4 shows the detail ‘Y’ of the fixing arrangement of the bumper beam to the vehicle body.

DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS

In the following, different embodiments of the present invention will be described in more details with reference to the accompanying drawings without limiting the scope and ambit of the present invention in any way.

Figure 1 shows a typical construction of the hybrid composite bumper beam 10 configured in accordance with the present invention. The composite bumper beam 10 includes a connecting member 1, a front member 2 made of Thermoplastic glass reinforced composite and a pair of shock absorbers 3 made of thermoset pultruded Glass Fibre Reinforced Plastic (GFRP) with a Thermoset Resin and disposed on either side of the front member 2.

Figure 2 shows a sectional representation along section A-A of the hybrid composite bumper beam of Figure 1 depicting the fixing arrangement of the front member 2 to the shock absorber 3. The front member 2 and the shock absorbers 3 are connected by a structural adhesive 6 in the additional flange 8 provided in the front member 2 and connecting the member 1 to the shock absorbers 3.

Figure 3 shows the detail ‘X’ of the fixing arrangement of the front member to the absorber. The front member 2 mounting the bumper 5 and the shock absorbers 3 are connected by means of a structural adhesive 6 in the additional flange 8 provided in the front member 2. Therefore, during impact at slow speeds, the shock energy is transferred from the bumper 5 to the front member 2 to the shock absorbers 3 (see Figure 2).

Figure 4 shows the detail ‘Y’ of the fixing arrangement of the composite bumper beam 10 to the vehicle body member 4. The bumper beam 10 is connected to the body member 4 by means of a plurality of bolts 7. Here also, the shock absorber 3 is shown connected by means of a structural adhesive 6 between the connecting member 1 and the shock absorber 3. Therefore, during impact at slow speeds, the shock energy is transferred from the bumper 5 to the front member 2 to the shock absorbers 3 (see Figure 2).

DESCRIPTION OF THE PRESENT INVENTION

Accordingly, the present invention concerns a light-weight hybrid composite bumper beam structure which includes a front member made of a polyamide based thermoplastic composite and provided with a pair of shock absorbers configured with pultruded Glass Fibre Reinforced Thermoset Composite. This material is suitable for manufacturing light-weight structural parts having optimal properties for resistance to heat ageing and over-moulding adhesion for functional integration. In contrast to the conventionally used high-strength steels and Aluminium having density of 7.8 and 2.7 g/cc, this thermoset pultruded Glass Fibre Reinforced Plastic (GFRP) material has a density of about 1.98 g/cc. Similarly, the strength of high strength steel and Aluminium is 250 MPa and 600-800 MPA, whereas the comparable strength of this GFRP material is in the range of 160 to 840 MPA, which can be chosen according to the strength requirement for such bumper manufacturing applications. Further, pultrusion process imparts high-strength and stiffness, low-density and makes the components corrosion resistant, therefore it is a cost-effective process for producing fiber-reinforced composite parts in accordance with the present invention.

The invention includes an integration of the front member with a crash box by using a structural adhesive. This front-member and crash box assembly is connected to the connecting member, again by using structural adhesive. The complete assembly is fixed to the body member by means of a plurality of bolts. The bumper beam for the front member made of a thermoplastic composite is manufactured by using a Thermo-Compression Moulding or Injection–Compression Moulding process or Hot stamping process.

The Glass Fibre Reinforced Plastic Thermoset Composite is manufactured by the pultruding process, in which the reinforcement materials such as fibres or woven or braided strands are impregnated with resin, if required, followed by a separate preforming system, and finally pulled through a heated stationary die wherein the resin undergoes polymerization.

This pultrusion process imparts high-strength and stiffness, low-density and makes the components corrosion resistant, therefore it is a cost-effective process for producing fiber-reinforced composite parts in accordance with the present invention.

The structural adhesive used for manufacturing hybrid composite bumper beam structure in accordance with the present invention offers a faster fixture time, optimal combination of high modulus and high elongation, substantially uniform mechanical properties like modulus and strength across a wide range of operating temperature, i.e. -300C to + 800C.
Therefore, the structural adhesive facilitates in excellent management of the differences in the thermal expansion with components made of dissimilar materials, as suggested according to the present invention.

Normally, the impregnation is done either by pulling these reinforcement materials through a bath or by injecting the resin into an injection chamber, generally connected to a heated stationary die.

TECHNICAL ADVANTAGES AND ECONOMIC SIGNIFICANCE

The hybrid composite bumper beam structure configured in accordance with the present invention has the following advantages:

• Low-weight as compared to metallic beam structure

• Anti-corrosive properties

• Aids in system integration

• Facilitates recycling of metallic components of the beam structure

• Applicable to both front and rear bumpers

• Usable with or without plastic or foam energy absorber set-up
• Simple joining of plastic components by adhesive bonding and joining of the metal structure by welding/bolting on BIW.

The exemplary embodiments described in this specification are intended merely to provide an understanding of various manners in which this embodiment may be used and to further enable the skilled person in the relevant art to practice this invention. The description provided herein is purely by way of example and illustration.

Although, the embodiments presented in this disclosure have been described in terms of its preferred embodiments, the skilled person in the art would readily recognize that these embodiments can be applied with modifications possible within the spirit and scope of the present invention as described in this specification by making innumerable changes, variations, modifications, alterations and/or integrations in terms of materials and method used to configure, manufacture and assemble various constituents, components, subassemblies and assemblies, in terms of their size, shapes, orientations and interrelationships without departing from the scope and spirit of the present invention.

While considerable emphasis has been placed on the specific features of the preferred embodiment described here, it will be appreciated that many additional features can be added and that many changes can be made in the preferred embodiments without departing from the principles of the invention.

These and other changes in the preferred embodiment of the invention will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.

Many of the fastening, connection, processes and other means and components utilized in this invention are widely known and used in the field of the invention described, and their exact nature or type is not necessary for an understanding and use of the invention by a person skilled in the art and they will not therefore be discussed in significant detail.

The numerical values given of various physical parameters, dimensions and quantities are only approximate values and it is envisaged that the values higher or lower than the numerical value assigned to the physical parameters, dimensions and quantities fall within the scope of the disclosure unless there is a statement in the specification to the contrary.

Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, shall be understood to implies including a described element, integer or method step, or group of elements, integers or method steps, however, does not imply excluding any other element, integer or step, or group of elements, integers or method steps.

The use of the expression “a”, “at least” or “at least one” shall imply using one or more elements or ingredients or quantities, as used in the embodiment of the disclosure in order to achieve one or more of the intended objects or results of the present invention.

Also, any reference herein to the terms ‘left’ or ‘right, ‘up’ or ‘down, or ‘top’ or ‘bottom’ are used as a matter of mere convenience, and are determined by standing at the rear of the machine facing in its normal direction of travel. Furthermore, the various components shown or described herein for any specific application of this invention can be widely known or used in the art by persons skilled in the art and each will likewise not therefore be discussed in significant detail. When referring to the figures, like parts are numbered the same in all of the figures. ,CLAIMS:We claim:

1. A hybrid composite bumper beam for an automobile, wherein the bumper beam comprises:

(i) a profiled front member configured made of thermoplastic composite material;

(ii) a composite crash box assembly including a pair of shock absorbers integrated with the front member by adhesive bonding and disposed on either side of the bumper; and

(iii) a respective connecting member connected on either side of the bumper to the body member of the automobile by a plurality of fasteners;

wherein the bumper is mounted on the profiled front member by means of a respective profiled connection provided on either side thereof by using an adhesive bonding therebetween, for transferring shock energy received by the bumper during impact of the automobile at slow speeds to the body member thereof.

2. Hybrid composite bumper beam as claimed in claim 1, wherein the crash box assembly comprises a pair of parallelly disposed straight glass fiber reinforced plastic plates connected by means of a structural adhesive to the front member at the front end thereof and to the connecting member at the rear end thereof.

3. Hybrid composite bumper beam as claimed in claim 2, wherein the profiled front member is configured with an opening on either side thereof for connection to a respective crash box assembly.

4. Hybrid composite bumper beam as claimed in claim 3, wherein each opening in the front member comprises an undulating curved profile bonded at the inner face of the respective crash box assembly and a curved flange at the outer face of the respective crash box assembly for adhesive bonding with a respective crash box assembly on either side of the bumper.
5. Hybrid composite bumper beam as claimed in claim 5, wherein the curved flanges are made of thermoplastic composite material and function as shock absorbers for transferring the shock energy received by the bumper during impact of the automobile at slow speeds, via the front member, crash box assemblies and the connecting members to the body member of the automobile.

6. Hybrid composite bumper beam as claimed in claim 1, wherein the connecting member is made L-shaped with the shorter arm thereof connected to the crash box assembly and the longer arm thereof fastened on the body member of the automobile.

7. Hybrid composite bumper beam as claimed in any one of claims 1 to 6, wherein the front member is made of thermoplastic glass reinforced composite and the shock absorbers are made of thermoset pultruded glass fiber reinforced plastic (GFRP) with a thermoset resin.

8. Hybrid composite bumper beam as claimed in any one of claims 1 to 7, wherein the front member is made of thermoplastic glass reinforced composite and the shock absorbers are made of thermoset pultruded glass fiber reinforced plastic (GFRP) with a thermoset resin.

9. Hybrid composite bumper beam as claimed in any one of claims 1 to 8, wherein a respective crash box assembly is connected to the front member by means of a structural adhesive.

10. Hybrid composite bumper beam as claimed in claim 1, wherein the front member is made of a polyamide based thermoplastic composite.

11. Hybrid composite bumper beam as claimed in claim 1, wherein the front member is manufactured by using thermo-compression moulding or injection-compression moulding process or Hot stamping process.

12. A pultruding process for making front member of the hybrid composite bumper beam as claimed in claim 10, the process comprises the steps of:

(I) Impregnating the reinforcement materials such as fibres or woven or braided strands with resin;

(II) Preforming the resin impregnated reinforcement materials to obtain the preformed front member, and

(III) Pulling the preformed front member through a heated stationary die for facilitating the polymerization of the resin impregnated therein.

13. Process as claimed in claim 11, wherein the impregnation is done by pulling these reinforcement materials through a bath.

14. Process as claimed in claim 11, wherein the impregnation is done by injecting the resin into an injection chamber connected to a heated stationary die.