FR3118753A1 - MOTOR VEHICLE PEDAL PROVIDED WITH A RIGIDIFICATION INSERT IN COMPOSITE MATERIAL - Google Patents

Abstract

The present invention relates to a pedal (10) in particular for a motor vehicle having an interface (12) for integrating a pivot connection and a shoe (11) against which the foot of a driver is intended to bear, said pedal (10) comprising: - a body (13) made of a plastic material, and - a stiffening insert (15), - the stiffening insert (15) being made of a composite material, said stiffening insert ( 15) comprising a matrix made of a thermoplastic polymer material and fibers extending inside the matrix, said body (13) of the pedal (10) being molded over the stiffening insert (15). Figure 1b

Description

MOTOR VEHICLE PEDAL PROVIDED WITH A RIGIDIFICATION INSERT IN COMPOSITE MATERIAL

The present invention relates to a motor vehicle pedal provided with a stiffening insert made of composite material. The invention finds a particularly advantageous, but not exclusive, application with brake pedals, accelerator pedals, or motor vehicle clutch pedals.

In a manner known per se, motor vehicle pedals can be made of a single-material thermoplastic material, of the polyamide or polypropylene type filled with glass fibers. However, pedals without an insert can be fragile and lack mechanical strength, which leads to the risk of breakage.

Safety pedals with high mechanical stress, such as brake pedals, are either made entirely of steel or made from a steel core overmolded with plastic. However, the metal core represents a significant mass in the total weight of the part.

Also known are pedals made from composite sheets (called "organo-sheet" in English). These composite sheets consist of a large bidirectional woven fiber web requiring long heating before being shaped by a hot stamping technique. These pedals have the advantage of being light but are nevertheless complex and expensive to produce. This type of pedal is therefore generally intended for luxury vehicles.

The invention aims to effectively remedy the aforementioned drawbacks by proposing a pedal, in particular for a motor vehicle, having an interface for integrating a pivot connection and a shoe against which the driver's foot is intended to bear, said pedal comprising:

- a body made of a plastic material, and

- a stiffening insert,

- the stiffening insert being made of a composite material, said stiffening insert comprising a matrix made of a thermoplastic polymer material and fibers extending inside the matrix, said body of the pedal being molded onto the stiffening insert.

The invention thus makes it possible, thanks to the presence of the stiffening insert, to considerably increase the mechanical strength of the pedal compared to a pedal made entirely of a plastic material. The invention also makes it possible to replace the metal inserts of a safety pedal with inserts made of a lighter and recyclable composite material. The invention makes it possible to produce a less expensive and more localized reinforcement than a pedal obtained from a composite material of the "organo-sheet" type. Thanks to the invention, it is possible to use materials that are more respectful of the environment for the overmoulding, such as plastic materials having vegetable fillers, or entirely recycled plastic materials.

According to one embodiment of the invention, the stiffening insert consists of several layers of tape superimposed on each other.

According to one embodiment of the invention, the stiffening insert takes the form of a reinforcement loop extending continuously along a complete circumference of the body of the pedal.

According to one embodiment of the invention, the stiffening insert extends along an upper face of the body of the pedal, a lower face of the body of the pedal, a lower end portion of the body connecting the upper face and the lower face lower part of the body, and an upper end portion of the body connecting the upper face and the lower face of the body.

According to one embodiment of the invention, the stiffening insert and the body of the pedal are made from the same thermoplastic material, in particular a polypropylene material.

According to one embodiment of the invention, the fibers of the stiffening insert are unidirectional.

According to one embodiment of the invention, the fibers of the stiffening insert extend along a direction of longitudinal elongation of the body of the pedal.

According to one embodiment of the invention, a width of the insert is constant along an entire length of the body of the pedal.

The invention also relates to a method of manufacturing a motor vehicle pedal comprising:

- a step of manufacturing a stiffening insert made of a composite material comprising a matrix made of a thermoplastic polymer material and fibers extending inside the matrix,

- a step of placing the stiffening insert inside an injection mold, and

- a plastic injection step for forming a body of the pedal, so that at least one side of the body comes into contact with the stiffening insert in order to ensure cohesion of material between the body of the pedal the pedal and the stiffening insert.

According to one implementation, the stiffening insert is made by winding layers of a heated tape around a template, so that the layers are superimposed on each other.

The invention will be better understood on reading the following description and on examining the accompanying figures. These figures are given only by way of illustration but in no way limit the invention.

Figures 1a and 1b are respectively perspective and longitudinal section views of a vehicle pedal according to the present invention;

There is a schematic representation of a tape used for making a stiffening insert according to the present invention;

There is a schematic representation of a robot used to produce a stiffening insert by winding a heated tape around a jig;

There is a perspective view of a stiffening insert for use with a motor vehicle pedal according to the invention;

Figures 5a, 5b, and 5c are schematic views of different steps of a method of manufacturing a vehicle pedal according to the present invention;

There is an enlarged view of the interface between the body of a pedal and the multilayer composite insert according to the present invention.

Identical, similar or analogous elements retain the same reference from one figure to another.

Figures 1a and 1b show a motor vehicle pedal 10 which may consist of an accelerator pedal, a clutch pedal, or a brake pedal.

The pedal 10 has at one of its ends a shoe 11 against which the driver's foot bears. On the side of the opposite end, the pedal 10 comprises an interface 12 for integrating a pivot connection. The interface 12 for integrating a pivot connection may for example consist of a through opening allowing the passage of a rod forming an axis of rotation X. This allows rotation of the pedal 10 relative to the body. of the vehicle when the driver presses the pedal 10 via the shoe 11. The pedal 10 may also include projections 14 in its intermediate part for the integration of a spring or cable return system.

The pedal 10 comprises a body 13 of elongated shape and at least one stiffening insert 15 made of a composite material. This stiffening insert 15 comprises a matrix 16 made of a polymer material and fibers 18 extending inside the matrix 16, as can be seen in .

The body 13 of the pedal 10 is molded over the stiffening insert 15. The body 13 may for example have an I-shaped cross section provided with a central rib 13.1 represented by transparency on the . The body 13 may further comprise stiffening ribs 17, in particular a network of cross-shaped ribs.

The fibers 18 may be chosen in particular from glass or carbon fibers. The stiffening insert 15 is made up of several layers of a tape 19 shown on the . The layers of ribbon 19 are superimposed on each other, as explained in more detail below.

The stiffening insert 15 may take the form of a reinforcement loop, as illustrated in the . The insert 15 then extends continuously along a complete circumference of the body 13 of the pedal 10.

The stiffening insert 15 thus extends along an upper face 20 of the body 13 of the pedal 10 and a lower face 21 of the body 13 of the pedal 10. The upper face 20 is located on the same side as the pad 11, while that the lower face 21 is located on the side opposite the pad 11. The stiffening insert 15 also extends along a lower end portion 22 of the body 13 connecting the upper face 20 and the lower face 21 of the body 13. The stiffening insert 15 also extends along an upper end portion 23 of the body 13 connecting the upper face 20 and the lower face 21 of the body 13. The stiffening insert 15 thus has a closed contour. Alternatively, the stiffening insert 15 may have a U-shape or a linear shape.

The continuous fibers 18 of the stiffening insert 15 work effectively in traction on the upper face 20 of the pedal 10 when the pedal 10 is depressed. The fibers 18 of the stiffening insert 15 also work effectively in traction on the underside 21 of the pedal 10 during the ascent of the pedal 10.

Advantageously, the stiffening insert 15 and the body 13 are made from the same thermoplastic material, in particular polypropylene. Alternatively, these elements may be made of polyamide (PA6 or PA6.6), polyvinyl chloride (PVC), or polybutylene terephthalate (PBT), or any other material suitable for the application.

The process for manufacturing the pedal 10 according to the invention provided with a stiffening insert 15 made of composite material is described below.

This method includes a step of manufacturing a stiffening insert 15 made of a thermoplastic material reinforced by fibers 18. For this purpose, as can be seen in the , a robot 25 performs a winding of layers of a tape 19 (cf. ) heated around a template 26, so that the layers are superimposed on each other. All of these layers are compressed or hot rolled to form the insert 15.

According to an exemplary embodiment, each layer of the tape 19 comprises a matrix 16 made of a thermoplastic polymer material in which extend continuous fibers 18, as shown in the . The fibers 18 are preferably unidirectional and extend along the length of the ribbon 19.

Tape width 19 is available in multiples of 1/4 inch (6.35mm). Advantageously, a width of the strip 19 and therefore of the insert 15 formed by a single width of strip 19 of between 2×1/4=0.5 inches (12.7mm) and 8×1/4=2 inches (50.8mm) is chosen.

In order to facilitate the production of the pedal 10, a width of the insert 15 is constant along an entire length of the body 13 of the pedal 10.

A thickness of a layer of tape 19 is of the order of 0.2mm. The layers are advantageously stacked, so that a total thickness of the insert 15 may be between a few tenths of a millimeter and several millimeters. A thickness of the insert 15 is in particular between 1mm and 5mm, and preferably between 1mm and 2mm. The thickness of the insert 15 (and therefore the number of layers of tape 19 stacked on top of each other) can of course be adapted according to the mechanical stresses intended to be supported by the insert 15.

The stiffening insert 15 is then preheated and placed in a plastic injection mold 28, as shown in the . A thermoplastic material, such as polypropylene, is injected into the mold 28 so as to produce the body 13 overmolded on the stiffening insert 15, as shown in the . The thermoplastic material of the body 13 is preferably loaded with fibers, in particular glass fibers, up to 30% by mass. The thermoplastic material is injected, so that at least one face of the body 13 comes into contact with the stiffening insert 15 in order to ensure material cohesion between the body 13 of the pedal 10 and the stiffening insert 15 .

The mold 28 is opened at the end of the process and the part 10 is removed from the mold after it has cooled, as shown in the . The pedal 10 thus obtained is reinforced locally in the zones that are highly stressed mechanically. The fibers 18 of the stiffening insert 15 extend along a direction of longitudinal elongation of the body 13 of the pedal 10.

There is an enlarged view of the interface I between the body 13 of the pedal 10 and the multilayer composite insert 15 at the end of the manufacturing process. In this example, there is an insert 15 formed by six layers C1-C6 of tape 19 each comprising a matrix 16 of thermoplastic material and continuous fibers 18 seen in cross section. An absence of porosity or air bubbles is observed at the interface I or between the layers C1-C6 of ribbon 19, so that there is no problem with the cohesion of the assembly. A one-piece insert 15 is thus obtained which has a continuity of material with the body 13 of the pedal 10. The mechanical connection between the body 13 of the pedal 10 and the insert 15 is therefore robust and homogeneous.

Claims (10)

Pedal (10), in particular for a motor vehicle, having an interface (12) for integrating a pivot connection and a shoe (11) against which the driver's foot is intended to bear, said pedal (10 ) comprising:
- a body (13) made of a plastic material, and
- a stiffening insert (15),
characterized in that the stiffening insert (15) is made of a composite material, said stiffening insert (15) comprising a matrix (16) made of a thermoplastic polymer material and fibers (18) extending to the inside the die (16), said body (13) of the pedal (10) being molded onto the stiffening insert (15). Pedal according to Claim 1, characterized in that the stiffening insert (15) consists of several layers of tape (19) superimposed on each other. Pedal according to Claim 1 or 2, characterized in that the stiffening insert (15) takes the form of a reinforcing loop extending continuously along a complete circumference of the body (13) of the pedal (10). . Pedal according to Claim 3, characterized in that the stiffening insert (15) extends along an upper face (20) of the body (13) of the pedal (10), a lower face (21) of the body (13 ) of the pedal (10), a lower end portion (22) of the body (13) connecting the upper face (20) and the lower face (21) of the body (13), and an upper end portion ( 23) of the body (13) connecting the upper face (20) and the lower face (21) of the body (13). Pedal according to any one of Claims 1 to 4, characterized in that the stiffening insert (15) and the body (13) of the pedal (10) are made from the same thermoplastic material, in particular a material in polypropylene. Pedal according to any one of Claims 1 to 5, characterized in that the fibers (18) of the stiffening insert (15) are unidirectional. Pedal according to Claim 6, characterized in that the fibers (18) of the stiffening insert (15) extend along a direction of longitudinal elongation of the body (13) of the pedal. Pedal according to any one of Claims 1 to 7, characterized in that a width of the insert (15) is constant along an entire length of the body (13) of the pedal (10). Method of manufacturing a motor vehicle pedal (10), characterized in that it comprises:
- a step of manufacturing a stiffening insert (15) made of a composite material comprising a matrix (16) made of a thermoplastic polymer material and fibers (18) extending inside the matrix (16) ,
- a step of placing the stiffening insert (15) inside an injection mold (28), and
- a plastic injection step for forming a body (13) of the pedal (10), so that at least one face of the body (13) comes into contact with the stiffening insert (15) in order to ensure material cohesion between the body (13) of the pedal (10) and the stiffening insert (15). Method according to Claim 9, characterized in that the stiffening insert (15) is produced by winding layers of a heated tape (19) around a template (26), so that the layers (C1-C6 ) are superimposed on each other.