FR2941892A1 - Door for motor vehicle, has reinforcements physically linked to thermoplastic material of outer skin, and metallic inner lining made of fiber reinforced thermoplastic/thermosetting material and assembled on circumference of outer skin - Google Patents

Abstract

The door has fiber based reinforcements physically linked to a thermoplastic material of an outer skin (10), where the material is reinforced with fibers e.g. glass, carbon, aramid and natural fibers. A metallic inner lining (11) is made of metallic material or fiber reinforced thermoplastic/thermosetting material, and is assembled on a circumference of the skin. The reinforcements are formed by a top frontal impact reinforcement (12), a lateral impact reinforcement (13), a skin tightener (14), a frame reinforcement (15), and hinge and lock reinforcements. The skin is externally covered by a thermoplastic finishing layer. An independent claim is also included for a method for manufacturing a door of a motor vehicle.

Description

AUTOMOTIVE VEHICLE DOOR COMPRISING INTEGRAL REINFORCEMENTS IN THE THERMOPLASTIC OUTER SKIN OF THIS DOOR AND METHOD FOR MANUFACTURING THE SAME.

The present invention relates to a motor vehicle door. Motor vehicle doors must contribute to the safety of occupants in the event of a side impact and frontal impact and withstand aerodynamic deflection, burglary and restraint forces from a human body.

These doors are usually made of steel or aluminum and generally have reinforcements to withstand frontal and lateral impacts. Figures 1 and 2 respectively show an external side view and a sectional view along the plane A-A of Figure 1 of a motor vehicle door of metal or aluminum.

This door has an outer skin 1 and an inner lining 2 made of sheet steel or aluminum. The interior of the door comprises between the outer skin 1 and the lining 2, three reinforcements 3, 4, 5 namely a frontal impact reinforcement 3 extending horizontally near the lower edge 6a of the frame 6 of the door, a skin tensioner 4 also extending horizontally under the reinforcement 3 and a lateral shock reinforcement 5 extending inclined under the skin tensioner 4. The reinforcements 3, 4 and 5 are steel profiles whose opposite ends are fixed to the side faces of the liner 2. The steel doors have the disadvantage of having a high mass: of the order of 20 Kg on average, the reinforcements 3, 4 and 5 represent about 2 to 3 Kg. high mase strike the total mass of the vehicle and the CO2 emissions of it. The mass of the aluminum doors is a little lower. However, they have the disadvantage of being more expensive to manufacture.

The object of the present invention is to overcome the disadvantages of motor vehicle doors described above. This object is achieved, according to the invention, thanks to a motor vehicle door comprising an outer skin and an inner lining and reinforcements, characterized in that the outer skin is made of thermoplastic material and at least some of the reinforcements are based on continuous fibers and are physically bonded to the thermoplastic material of the outer skin and in that the liner is assembled around the periphery of this outer skin.

Such a door has a much lower mass than conventional metal doors because its skin is thermoplastic material and the reinforcements are based on fibers, whose density is lower than that of steel and aluminum. Moreover, since the reinforcements are physically linked to the outer skin and not to the lining, they allow the energy of a lateral impact to be absorbed earlier in time than when they are attached to the skin. lining. This results in increased safety for the occupants of the vehicle. The lining of the door according to the invention may be metallic. However, preferably, the liner is made of thermoplastic or thermosetting material reinforced with fibers. In this case, the total mass of the door is much lower than that of a conventional metal door. Also preferably, said reinforcements are overmolded with the thermoplastic material of the outer skin.

In this case, the manufacture of the door is particularly simple, since the reinforcements are attached to the outer skin during a single overmolding operation. In a preferred version of the invention, the reinforcements comprise several reinforcements chosen from the following: lateral impact reinforcement, skin tensioner, reinforcement of the door frame, hinge reinforcements and reinforcement of the lock. The outer skin can of course integrate all the reinforcements above. Preferably, the lateral impact reinforcement is connected by its opposite ends to the reinforcement of the upper hinge and to the reinforcement of the lock and one of the ends of the skin tensioner is bonded to the reinforcement of the lower hinge. This gives a physical connection by overmolding the thermoplastic material particularly strength between the various reinforcements above, without it being necessary to make other physical connections with the lining of the door. Also preferably, the thermoplastic material of the outer skin is reinforced with fibers selected from glass, carbon, aramid fibers and natural fibers. In a particularly advantageous version of the invention, the outer skin is coated externally by a top coat of paintable thermoplastic material. This topcoat gives the outer skin a surface appearance called class A by the specialists. According to another aspect of the invention, the method of manufacturing a motor vehicle door, according to the invention, is characterized by the following steps: - it is placed in a mold, whose bottom has a contour corresponding to that of the outer skin that is to be made, the reinforcements in continuous fibers by moving them away from the bottom of the mold and placing them in the desired geometric positions; - a sufficient quantity of thermoplastic material is injected into the mold to overmold the reinforcements in this mold; material. Preferably, this method also comprises the following step: the outer face of the outer skin is covered by overmolding or co-molding with a topcoat of paintable thermoplastic material. Preferably, the reinforcements are preformed and / or pre-impregnated before being introduced into the mold and at least some of the reinforcements are bonded to one another before being introduced into the mold.

In a final step, the outer skin is assembled with the door liner by gluing or heat sealing. Other features and advantages of the invention will become apparent throughout the description below. In the accompanying drawings, given by way of nonlimiting example: FIG. 3 is a side view of a motor vehicle door, according to the invention; FIG. 4 is a sectional view along the Al-Al plane; FIG. 5 is a sectional view along the plane BB of FIG. 1; FIG. 6 is a diagram showing a first step of the manufacturing method according to the invention; FIG. in schematic section showing the outer skin, obtained after the first step; FIG. 8 is a view similar to FIG. 7, after application of a topcoat. The motor vehicle door shown in FIGS. 3, 4 and 5 comprises an outer skin 10 and an inner liner 11 as well as reinforcements 12, 13, 14.

According to the invention, the outer skin 10 is made of thermoplastic material and the reinforcements 12, 13, 14 are based on continuous fibers and are physically bonded to the thermoplastic material of the outer skin 10. The lining 11 is assembled on the periphery of the outer skin 10, as shown in FIG. 5.

This liner 11 may be metallic. However, preferably, this liner 11 is made of thermoplastic or thermosetting material reinforced with fibers. In a preferred version of the invention, the reinforcements 12, 13, 14 are overmolded with the thermoplastic material of the outer skin 10.

The reinforcements 12, 13, 14 are constituted respectively by an upper frontal impact reinforcement 12, a lateral shock reinforcement 13, a skin tensioner 14, a reinforcement 15 of the door frame located on the periphery of the outer skin 10, and two hinge reinforcements 16 and reinforcement of the lock 17. The reinforcements 12, 13, 14 consist of continuous glass, carbon, aramid fibers preformed and / or pre-impregnated with thermoplastic material and have the shape of a profile. extending substantially across the entire width of the outer skin 10. The hinge reinforcements 16 and the lock reinforcements 17 are located near the lateral edges of the skin 10 and are in the form of plates which are also reinforced with fibers, such as those mentioned above. The reinforcements 12 and 13 increase the resistance of the door with respect to frontal and lateral impacts.

The skin tensioner 14 has the effect of maintaining the curve of the skin 10 by limiting the depression of the latter by a support exerted on the skin. In the example shown (see Figure 4) the reinforcements 13 and 14 have a rectangular section, while the reinforcements 12 and 15 have a circular section.

In addition, the lateral shock reinforcement 13 is connected by its opposite ends to the reinforcement 16 of the upper hinge and the reinforcement of the lock 17. Moreover, one of the ends of the skin tensioner 14 is connected to the reinforcement 16 of the lower hinge. The thermoplastic material of the outer skin 10 is reinforced with fibers selected from glass, carbon, aramid fibers and natural fibers. Preferably, the thermoplastic material of the outer skin 10 is a material which is resistant to a temperature equal to or greater than 160 ° C which is used when drying the paint which is subsequently applied to the door.

Preferably, the outer skin 10 is coated externally with a topcoat of paintable thermoplastic material, such as polyamide which makes it possible to obtain an external appearance, referred to as class A by the specialists. The method of manufacturing the motor vehicle door that has just been described comprises the following steps: - Place (see Figure 6) in a mold 18, the bottom has a contour corresponding to that of the outer skin 10 that it is desired to make the reinforcements 13, 14, 15 in continuous fibers by moving them away from the bottom of the mold 18, for example by means of pins, and placing them in the desired geometric positions. Before the reinforcement 13 and 14 are introduced into the mold 18, they are connected to the hinge 16 and lock 17 reinforcements. A sufficient quantity of thermoplastic material is then injected into the mold 18 to overmold the reinforcements 13, 14, 15, 16, 17 in this material, as shown in Figure 7. - Preferably, the outer face of the outer skin 10 is over-molded or co-molded by a finishing layer 19 of a pliable thermoplastic material, as shown in FIG. FIG. 8. The reinforcements 13, 14, 15, 16 and 17 are preferably preformed and / or pre-impregnated to ensure their cohesion before being introduced into the mold 18.

The above method is relatively simple to implement and provides an excellent physical connection between the various reinforcements and the outer skin 10. In a final step, the outer skin is assembled with the door liner 11 by gluing or heat sealing. This door liner 11 is preferably obtained by molding a thermoplastic or thermosetting material reinforced with supporting fibers such as that of the outer skin 10, a temperature of at least 160 ° C. The main advantages of the invention are as follows.

It allows for motor vehicle doors whose mass is significantly lower than that of conventional metal doors. The weight saving can indeed reach 50% compared to a sheet metal door. The invention allows in a single overmolding operation to integrate all the necessary reinforcements in the outer skin of the door.

Given in particular that the lateral shock reinforcement 13 is integrated with the outer skin 10, this reinforcement is capable of absorbing the energy of a lateral shock from the beginning of the deformation of the outer skin and the occupants of the vehicle are better protected against the risk of injury. In addition, the realization of thermoplastic automotive vehicle doors provides aesthetic aspects and shapes that can not be obtained by the process of stamping metal doors.

Claims (14)

REVENDICATIONS1. Motor vehicle door comprising an outer skin (10) and an inner liner (11) and reinforcements (12, 13, 14, 15, 16, 17), characterized in that the outer skin (10) is of thermoplastic material and at least some of the reinforcements (12, 13, 14, 15, 16, 17) are based on continuous fibers and are physically bonded to the thermoplastic material of the outer skin (10) and in that the liner (11) is assembled on the periphery of this outer skin (10). 2. Motor vehicle door according to claim 1, characterized in that the lining (11) is metallic. 3. Motor vehicle door according to claim 1, characterized in that the lining (11) is made of thermoplastic or thermosetting material reinforced with fibers. Motor vehicle door according to one of Claims 1 to 3, characterized in that the said at least some of the reinforcements (12, 13, 14, 15, 16, 17) are overmoulded with the thermoplastic material of the outer skin ( 10). 5. Motor vehicle door according to one of claims 1 to 4, characterized in that the reinforcements comprise several reinforcements selected from the following: side impact reinforcement (13), skin tensioner (14), frame reinforcement door (15), hinge reinforcements (16) and reinforcement of the lock (17). 6. Motor vehicle door according to claim 5, characterized in that the lateral impact reinforcement (13) is connected by its ends opposite the reinforcement of the upper hinge (16) and the reinforcement of the lock (17). 7. Motor vehicle door according to claim 6, characterized in that one end of the skin tensioner (14) is bonded to the reinforcement of the lower hinge (16). Motor vehicle door according to one of Claims 1 to 7, characterized in that the thermoplastic material of the outer skin (10) is reinforced with fibers chosen from glass, carbon and aramid fibers and fibers. natural. 9. Motor vehicle door according to one of claims 1 to 8, characterized in that the outer skin (10) is coated externally by a top coat (19) of paintable thermoplastic material. 10. A method of manufacturing a motor vehicle door according to one of claims 1 to 9, characterized by the following steps: - it is placed in a mold (18), whose bottom has a contour corresponding to that of the skin outer part (10) which is to be made, the reinforcements (13, 14, 15, 16, 17) made of continuous fibers by moving them away from the bottom of the mold (18) and placing them in the desired geometric positions, - injecting in the mold (18) a sufficient amount of thermoplastic material to overmold the reinforcements (13, 14, 15, 16, 17) in this material. 11. Manufacturing process according to claim 10, further comprising the following step: the outer face of the outer skin (10) is covered by overmoulding or co-molding by a finishing layer (19) made of a paintable thermoplastic material. 12. Method according to one of claims 10 or 11, characterized in that the reinforcements (13, 14, 15, 16, 17) are preformed and / or pre-impregnated before their introduction into the mold (18). 13. Method according to one of claims 10 to 12, characterized in that at least some of the reinforcements (13, 14, 15, 16, 17) are connected to each other before being introduced into the mold (18 ). 14. Method according to one of claims 10 to 13, characterized in that the outer skin (10) is assembled with the door liner (11) by gluing or heat sealing.