FR3052397A1 - COMPOSITE COMPOSITE SIDE SHOCK REINFORCEMENT FOR A MOTOR VEHICLE DOOR - Google Patents

Abstract

The invention relates to a lateral impact reinforcement for a motor vehicle side door, the two opposite ends (10a, 10b) of this reinforcement being intended to be fixed respectively near the rear edge and the front edge of the door lining, reinforcement (10) being made of composite material consisting of polymer and fibers, characterized in that said reinforcement (10) has areas (11a, 12a) whose thickness (E) is greater than the thickness (e) of the rest reinforcement (10).

Description

COMPOSITE SHOCK REINFORCEMENT FOR SIDE DOOR OF MOTOR VEHICLE

The present invention relates to a shock absorber for a motor vehicle side door, the two opposite ends of this reinforcement being intended to be fixed respectively near the rear edge and the front edge of the lining of the door. The invention also relates to a motor vehicle whose side doors are each equipped with a side impact reinforcement according to the invention positioned between the liner and the outer panel of the door.

FIG. 1 shows the lining 1 of a side door of a motor vehicle equipped with a side impact reinforcement 2. One of the two ends of the reinforcement 2 is fixed near the front edge 1b of the liner 1. other end of the reinforcement 2 is fixed near the rear edge 1a of the lining 1.

Figure 2 shows the outer skin 3 which covers the lining 1.

The lateral impact reinforcement 2 serves to protect the occupants of the vehicle in the event of a side impact.

Known reinforcements of this type are usually made of sheet steel or aluminum but have the disadvantage of increasing the mass of vehicles and therefore their fuel consumption.

In addition, these reinforcements degrade the quality of the noise generated when closing the doors.

Indeed, this noise is perceived as being too metallic and not enough "deaf".

The Applicant has developed a side door reinforcement, composite material, that is to say made of polymer coated fibers. More specifically, this reinforcement is manufactured by stamping fibers coated with plastic material in the form of a woven (fabric) or superimposed and crossed unidirectional fiber strips. During this stamping, the woven, for example, is deformed, similar to the stamping of a sheet. The opposite ends of the reinforcement obtained are flattened to facilitate their attachment to the lining of the door.

Such a reinforcement is described in particular in FR 3,023,237, which proposes a lateral impact reinforcement for a motor vehicle side door, the two opposite ends of which are designed to be fastened respectively near the rear edge and the front edge of the liner. the door. This reinforcement is made of composite material consisting of polymer and fibers, and has a cross section that varies and whose developed length is substantially constant along the length of the reinforcement between its two opposite ends.

Such a reinforcement has many advantages because it can be obtained by stamping a polymer-coated fiber fabric which has before stamping a rectangular shape or the developed form of the reinforcement and the fibers are aligned in the direction of the length and the width of the reinforcement or main efforts.

Thus, said fabric undergoes few cuts after stamping, capable of forming significant drops and the fibers are continuous from one end to the other of the reinforcement.

As a result, the mechanical properties of the reinforcement are very satisfactory.

However, during a side impact, it is known that a reinforcement is flexed, that is to say that a portion of the reinforcement section is biased in tension while the other part is stressed in compression.

In the case of a metallic reinforcement, the compressive strength is equivalent to or even greater than the tensile strength. In the case of a continuous fiber composite reinforcement, the breaking strength in compression is lower than the tensile strength, of the order of 50 to 70%.

The present invention therefore aims to provide a lateral reinforcement composite material whose compressive strength is improved. To this end, the subject of the invention is a side impact reinforcement for a motor vehicle side door, the two opposite ends of this reinforcement being intended to be fixed respectively near the rear edge and the front edge of the door lining, reinforcement being a composite material consisting of polymer and fibers, characterized in that said reinforcement has areas whose thickness is greater than the thickness of the remainder of the reinforcement.

Advantageously, these zones of the reinforcement whose thickness is increased relative to the thickness of the remainder of the reinforcement make it possible to reinforce the compressive strength of this reinforcement at said zones.

According to a preferred embodiment, the cross section of the reinforcement has on one of its faces at least one hollow and on its opposite side a projection, the thickness of the reinforcement at the top of the projection or the bottom of the hollow being greater than the thickness of the rest of the reinforcement.

Thus, the top of the projection which, once the reinforcement mounted on a vehicle door, is on the outside of the vehicle, works mainly in compression while the rest of the reinforcement works in tension. The extra thickness of the top of the projection therefore increases the compressive strength of said zone.

Preferably, the cross section of the reinforcement according to the invention may have at least one form of U, V or omega, open or closed.

According to a preferred embodiment, the cross section of the reinforcement has a form of double omega open, thus forming on one of the faces of the reinforcement two projections or bumps intended to be positioned on the outside of the vehicle, the reinforcement having at the vertices a thickness greater than that of the rest of the reinforcement. Preferably, this extra thickness of the peaks of the bumps is constant over almost all the reinforcement in length.

At least the end intended to be positioned on the front side of the liner is flattened because there is no room because of the congestion related to the hinges of the door. The opposite end of the reinforcement may be less flattened. Preferably, the two opposite ends of the reinforcement can be flattened.

These two flattened ends facilitate fixing the reinforcement on the lining of a vehicle door.

Also preferably, the fibers are arranged to be continuous, including in the areas of extra thickness and in the two opposite ends of the reinforcement.

According to an alternative embodiment, it is also possible for the fibers of the reinforcement to consist, for example, of fibers extending perpendicularly to one another either in the form of a woven fabric or in the form of unidirectional fiber sheets (UD) positioned according to 0 ° / 90 ° directions. On the other hand, at the level of the extra thicknesses of the bumps, unidirectional single fibers are preferred at 0 ° in the direction of the longitudinal axis of the reinforcement. It is also possible to consider a layer of fibers at 90 ° siperposant the unidirectional layers at 0 ° over a large part of the section, to ensure good stamping (no misalignment / sliding of the UD fibers during the implementation form).

Preferably, the cross section of the reinforcement varies and the developed length of this section is substantially constant along the length of the reinforcement between its two opposite ends.

According to another aspect, the invention also relates to a motor vehicle whose side doors are each equipped with a lateral impact reinforcement according to the invention. Other features and advantages of the invention will become apparent throughout the description below.

In the accompanying drawings, given by way of non-limiting example: FIG. 1 is a perspective view of a vehicle side door liner comprising a lateral impact reinforcement; - Figure 2 is a perspective view of the outer panel of the side door; FIG. 3 is a plan view of a lateral impact reinforcement according to the invention; FIG. 4 is a sectional view along line AA of a lateral impact reinforcement according to FIG. 3; FIG. is a plan view of a fiber fabric used to manufacture the reinforcement shown in FIG.

The two opposite ends 10a, 10b of the reinforcement 10 according to the invention are intended to be fixed respectively near the rear edge 1a and the front edge 1b of the lining 1 of the door, shown in FIG.

The reinforcement 10 is made of composite material consisting of polymer and fibers. By way of example, the polymer may be chosen from polypropylene, a polyamide PA, PA6, PA66, in particular for temperature resistance, and the fibers may be glass fibers.

According to a preferred embodiment, the cross section of the reinforcement 10 varies and the developed length of this section is substantially constant along the length of the reinforcement 10 between its two opposite ends 10a, 10b.

The lateral impact reinforcement 10 according to the invention is obtained by stamping a fabric of polymer-coated fibers.

In the example shown in Figures 3 and 4, the reinforcement 10 has two ribs 11,12 extending from one end to the other of the reinforcement 10 along the longitudinal axis and whose section is in the form of double omega . These ribs 11, 12 form two bumps or protrusions on the opposite face of the reinforcement 10 which constitute zones of compression of the reinforcement 10.

The fabric T has, before stamping, a rectangular shape or the developed form 10 '(flattened) of the reinforcement 10 and the fibers are aligned in the direction of the length and the width of the reinforcement 10 or main efforts (cf. Figure 5).

In addition, the fabric T undergoes little cutting after stamping may form significant falls.

Thus, the fibers remain continuous from one end to the other of the reinforcement 10.

Before stamping, therefore, strips of BF fibers are deposited on the flattened form 10 '(see FIG. 5) on the areas of the fabric T which correspond, after embossing, to the top of the bump (s) (or bottom of the ribs 11, 12) of the reinforcement 10. These strips of BF fibers make it possible to locally increase the thickness of the fabric T and the areas where these bands of BF fibers are located after shaping will constitute the vertices 11a, 12a of the projections and will then have a thickness E greater than that e of the remainder of the reinforcement 10.

As can be seen in FIG. 4, which represents a section in cross section of the reinforcement, a variation of the thickness of said reinforcement 10 between the peaks of the projections 11a, 12a of thickness E greater than the thickness e is thus obtained. from the rest of the reinforcement 10.

It is further seen that the two opposite ends 10a, 10b of the reinforcement 10 are flattened, which facilitates their attachment to flat portions of the lining of a door.

The fibers contained in the reinforcement 10 are continuous, including in the two opposite ends 10a, 10b.

The flattened ends 10a, 10b of the reinforcement increase the width of the reinforcement, but the developed length of the cross section remains the same as in the central zone of the reinforcement.

The implementation of a reinforcement according to the invention can be carried out using a conventional stamping process which generally uses flat products with a constant thickness, the excess thickness can then be implemented using patches deposited at appropriate areas.

A reinforcement according to the invention can also be made by manual or automatic lay-up by robot, consisting of depositing / positioning strips of the fibers (initially wound on rollers): directly on a mold representing the final shape of the piece or on a flat product to be subsequently shaped (essentially for thermoplastic composites).

The latter method is particularly advantageous for parts with complex geometry with small radii such as automotive parts, a robot that does not have access to the deposit in the bottom of the double omega, for example.

This process is the most interesting from an economic point of view because we put the material where we want and we avoid material falls.

Unidirectional fiber webs are preferably used, but from a functional point of view, it is also advantageous to have woven fabrics because they are better in terms of breaking strength, stress distribution, and elongation.

Claims (9)

1. Side impact reinforcement for a motor vehicle side door, the two opposite ends (10a, 10b) of this reinforcement being intended to be fixed respectively near the rear edge and the front edge of the door lining, this reinforcement (10 ) being made of composite material consisting of polymer and fibers, characterized in that said reinforcement (10) has areas (11a, 12a) whose thickness (E) is greater than the thickness (e) of the remainder of the reinforcement ( 10). 2. Reinforcement according to claim 1, characterized in that the cross section of the reinforcement (10) has on one of its faces at least one rib (11, 12) forming on its opposite side a bump or projection, the thickness (E) the reinforcement (10) at the top (11a, 12a) of the projection being greater than the thickness (e) of the remainder of the reinforcement (10). 3. Reinforcement according to claim 2, characterized in that the cross section of the reinforcement (10) has at least one form of U, V or omega, open or closed. 4. Reinforcement according to claim 2 or 3, characterized in that the cross section of the reinforcement (10) has a form of double omega open, thus forming on one of the faces of the reinforcement two projections or bumps (11, 12) intended to be positioned on the outside of the vehicle, the vertices (11a, 12a) are thicker than the rest of the reinforcement (10). 5. Reinforcement according to one of claims 2 to 4, characterized in that the extra thickness of the peaks of the bumps is constant over almost all of the reinforcement (10) in length. 6. Reinforcement according to one of claims 1 to 5, characterized in that the two opposite ends (10a, 10b) of the reinforcement (10) are flattened. 7. side impact reinforcement according to one of claims 1 to 6, characterized in that it consists of a polymer-coated fiber fabric, fiber strips (BF) having been deposited on the flattened form on areas of the fabric that correspond, after forming by stamping, to the vertices of the projections of thickness (E) greater than that (e) of the rest of the reinforcement (10). 8. Side impact reinforcement according to claim 7, characterized in that said fabric has before stamping a rectangular shape or the developed form (flattened) of the reinforcement and the fibers are aligned in the direction of the length and width of the reinforcement (10) or main efforts. 9. Motor vehicle whose side doors are each equipped with a side impact reinforcement (10) according to one of claims 1 to 8.