EP2250335B1 - Assembly including a body-in-white and tailgate for automobile - Google Patents

Description

The present invention relates to the technical field of opening of a motor vehicle, and in particular tailgate of such a vehicle.

In the prior art is known a motor vehicle tailgate comprising a rigid box made of thermoplastic material reinforced with glass fibers, the box being reinforced by a metal structure. This is the case, for example, for the Mazda 5 vehicle currently on the market. The tailgate is movably mounted on the white body of the motor vehicle between an open position and a closed position. It is connected to the body by means of hinges located in the upper part of the box and by cylinders allowing the assisted opening thereof.

The metal structure of the tailgate box allows it to comply with aesthetic specifications because its stiffening prevents it from deforming when it is in the closed position on the body. The metal structure also avoids fatigue that can lead to breakage of the box.

Indeed, each jack exerts a push on the tailgate placed in the open or closed position on the body. This thrust generating constraints in the tailgate, it may deform, which is not acceptable for the aesthetics of the vehicle, especially when the tailgate is mounted in closed position on the body. The games and outcrops of the hatchback body parts with the surrounding body parts are indeed determined very precisely and must not be modified by the deformation of the tailgate.

But such a tailgate, because of the metal structure of the box, does not meet the current need to lighten the motor vehicle.

The document EP 0 808 982 A2 describes an assembly according to the preamble of claim 1.

• A cet effet, l'invention a pour objet un ensemble d'une caisse de véhicule automobile et d'un hayon monté mobile sur la caisse entre une position ouverte et une position fermée selon la revendication 1.

The present invention aims to provide a solution to this need, with a tailgate whose box is made mainly of plastic, including thermoplastic fiber reinforced material. Such a hatchback would comply with the aesthetic specifications with regard to the play and outcropping between the bodywork of the tailgate and the rest of the bodywork of the vehicle. It would also prevent fatigue resulting from the deformation of the tailgate and can lead to breakage of the box.

• For this purpose, the subject of the invention is an assembly of a motor vehicle body and a tailgate movably mounted on the body between an open position and a closed position according to claim 1.

Thus, at least part of the stresses generated by the opening assistance means when the tailgate is placed in the closed position are compensated by the force exerted by the body on the opening assistance means.

The tailgate is less stressed by the thrust of the cylinders when it is placed in closed position on the body. Its rigidity can be reduced. It is then possible to lighten the tailgate while respecting the aesthetic specifications and mechanical strength of the vehicle.

In particular, the stop is arranged so that the opening assistance means is in abutment on the stop when the tailgate is placed in closed position on the body. The reaction force exerted by the abutment on the opening assistance means thus makes it possible to oppose the thrust force of the means for assisting the opening.

According to the invention, at least one of the stops is arranged so that the connecting piece bears against the stop when the tailgate is placed in closed position on the body. This prevents the end of the piston, which is generally plastic, is damaged by friction against the stop, which could cause a separation of the piston and the connecting piece.

Still according to the invention, the assembly comprises means for centering the connecting piece relative to the body, when the tailgate is placed in closed position on the body. This is particularly advantageous when the bearing surface of the abutment of the body does not intersect the piston thrust axis, since this makes it possible to prevent certain movements of the connecting piece and also to oppose the created torque. by the pushing force and the reaction force, these two forces not being collinear.

Finally, at least one of the abutments comprises a groove in which a projection of substantially complementary shape of the groove, integral with the connecting piece, is adapted to engage when the tailgate is placed in closed position on the body. Thus, the connecting piece is stationary in rotation, at least in a direction perpendicular to the tailgate due to the presence of the groove. As a result, the torque does not deform the connection piece in torsion. The tailgate does not move in relation to its original position.

• le moyen d'assistance à l'ouverture peut également comprendre au moins une pièce de liaison, de préférence métallique, reliant le vérin au hayon, au moins une surface de la butée sur laquelle est apte à s'appuyer le moyen d'assistance à l'ouverture est de normale essentiellement parallèle à l'axe de poussée. Par "essentiellement parallèle à l'axe de poussée", on entend que la normale à la surface de butée n'est pas inclinée de plus de 45° relativement à l'axe de poussée. De cette façon, la force de réaction de la butée s'oppose plus efficacement à la poussée du vérin lorsque le hayon est en position fermée,
• au moins une des butées est agencée sur la caisse de sorte qu'au moins une surface d'appui de la butée intersecte l'axe de poussée lorsque le hayon est placé en position fermée sur la caisse. On appelle "surface d'appui" la surface de la butée destinée à être en contact avec le vérin ou la pièce de liaison. Cette surface n'est pas obligatoirement constituée par la totalité d'une face de la butée. Dans ce mode de réalisation, du fait que l'appui sur la butée s'effectue selon l'axe de poussée, la poussée du piston n'est pas susceptible de donner naissance à un couple engendrant des contraintes dans le hayon;
• au moins une des butées est agencée de sorte qu'une extrémité du vérin est en appui contre la butée lorsque le hayon est placé en position fermée sur la caisse ;
• la butée est formée sur la caisse par emboutissage. De ce fait, les coûts de fabrication de la butée sont très peu élevés puisque sa fabrication ne demande pas d'étape spécifique supplémentaire, celle-ci étant formée en même temps que le reste de la caisse. Elle peut également être rapportée, par exemple par soudure sur la caisse ;
• le hayon comporte un caisson réalisé au moins partiellement en matière plastique, notamment en matériau thermoplastique, en particulier renforcé, tel que le polypropylène renforcé de fibres de verre, ce qui permet d'alléger substantiellement le véhicule automobile.

The invention may also include one or other of the features of the following list:

• the means for assisting the opening may also comprise at least one connecting piece, preferably metal, connecting the jack to the tailgate, at least one surface of the stop on which is able to rest the means of assistance to the opening is normal substantially parallel to the thrust axis. By "substantially parallel to the thrust axis" is meant that the normal to the abutment surface is not inclined by more than 45 ° relative to the axis of thrust. In this way, the reaction force of the stop is more effectively opposed to the thrust of the cylinder when the tailgate is in the closed position,
• at least one of the abutments is arranged on the body so that at least one bearing surface of the abutment intersects the thrust axis when the tailgate is placed in closed position on the body. The "bearing surface" is the surface of the abutment intended to be in contact with the jack or the connecting piece. This surface is not necessarily constituted by the entire face of the abutment. In this embodiment, because the support on the abutment is carried out along the axis of thrust, the thrust of the piston is not likely to give rise to a torque generating constraints in the tailgate;
• at least one of the stops is arranged so that one end of the jack is in abutment against the stop when the tailgate is placed in closed position on the body;
• the abutment is formed on the box by stamping. As a result, the manufacturing costs of the abutment are very low since its manufacture does not require any additional specific step, this being formed at the same time as the rest of the box. It can also be reported, for example by welding on the body;
• the tailgate comprises a box made at least partially of plastic, in particular thermoplastic material, in particular reinforced, such as polypropylene reinforced with glass fibers, which allows to substantially lighten the motor vehicle.

• la figure 1 est une vue schématique latérale de l'arrière d'une structure d'un véhicule automobile, montrant un hayon en position ouverte,
• la figure 2 est une vue en perspective d'un détail d'un ensemble de la caisse et du hayon, lorsque le hayon est placé dans une position ouverte de quelques degrés sur la caisse,
• la figure 3 est une vue en perspective de l'ensemble de la figure 2, lorsque le hayon est placé en position fermée sur la caisse,
• la figure 4 est une vue en perspective d'un détail d'un l'ensemble selon un mode de réalisation de l'invention, lorsque le hayon est placé en position fermée sur la caisse.

The invention will be better understood on reading the description which follows, given solely by way of example and with reference to the drawings in which:

• the figure 1 is a schematic side view of the rear of a structure of a motor vehicle, showing a tailgate in the open position,
• the figure 2 is a perspective view of a detail of an assembly of the body and the tailgate, when the tailgate is placed in an open position a few degrees on the body,
• the figure 3 is a perspective view of the whole of the figure 2 when the tailgate is placed in the closed position on the body,
• the figure 4 is a perspective view of a detail of an assembly according to one embodiment of the invention, when the tailgate is placed in closed position on the body.

We have shown on the figure 1 the rear of a motor vehicle structure 10, constituted by the white box of this motor vehicle. As can be seen, the body 10 comprises in particular two rear uprights 12 delimiting the rear of the vehicle, and a roof pillar 14 delimiting the upper part of the vehicle.

Between the two rear uprights 12 located on each side of the vehicle, is placed a hatch 16 forming opening of the vehicle, consisting of a tailgate box covered by body parts and a rear window. This hatch 16 is mounted movably on the body between an open position and a closed position. It is connected to the white box 10 by means of hinges 18 placed at the upper end of the tailgate and by jacks 20, located on each side of the tailgate and to assist the opening thereof.

Each cylinder 20 comprises a frame 22, one end 24 is connected to the body and is rotatable relative to the body. A piston 26 is engaged in this frame 22, so that the piston is movable in translation relative to the frame 22 along an axis corresponding to the longitudinal axis X of the jack. Each cylinder 20 exerts on the tailgate a steering thrust corresponding to the axis of translation of the piston, tending to place the tailgate in the closed position in the closed position. The piston 26 is connected to the tailgate 16 via an end 28, opposite the end 24 of the frame.

The end 28 of the piston is connected to a connecting piece 30 of longitudinal direction substantially perpendicular to the axis of translation of the piston, regardless of the position of the tailgate. This part 30 is also fixed on the side of the tailgate box, by means of screws 32. As can be seen in FIG. figure 2 , the connecting piece 30 comprises a body 34 in the form of a cone and comprises at its end a plate 36, the latter being fixed on the tailgate using screws or rivet 32. The connecting piece 30 also has at its end opposite to the plate a convex shape such as a ball The end 28 of the piston forms a concave portion intended to cooperate with the ball carried by the connecting piece, for example by clipping on it.

The assembly of the cylinder and the connecting piece forms a means of assisting the opening of the tailgate.

As we also see on the figure 2 , the amount 12 of the box is formed at its rear end by a profile having a generally U-shaped and comprising a bottom 38 and two side walls 40. The tailgate consists of a box 42 forming at its end a U-shaped section 44, on which is glued a rear window 46, so that the tailgate form at this location hollow body stiffening. The tailgate box is made of plastic material, especially reinforced thermoplastic material, such as polypropylene reinforced with glass fibers. The bezel is usually made of glass.

The white box further comprises a stop 48, formed by stamping, along with the rest of the box. This abutment comprises an upper face and four lateral faces connecting the upper face to the rest of the body. As is visible on the figure 3 representing the tailgate in the closed position, this stop serves as support for the connecting piece 30 when the tailgate box 42 is placed on the body 12 in the closed position. The connecting piece 30 is supported on a lateral face of the abutment facing upwards from the vehicle and normal substantially parallel to the axis of translation of the piston when the tailgate is placed on the body 12 in the closed position.

In this way, the force exerted by the stop on the piston opposes the pushing force of the piston on the tailgate. Stresses due to the thrust of the piston are not transmitted to the tailgate, whose rigidity can be reduced.

It should be noted that there must be a tight clearance between the connecting piece 30 and the stop 48 so that the thrust force of the piston does not generate excessive stresses in the tailgate.

We have shown on the figure 4 a detail of an assembly according to one embodiment of the invention. The references are identical with those of figures 2 and 3 if the objects designated by these references are identical.

In this embodiment, the body 49 and the tailgate box 42 are also connected via the cylinder 20 comprising a piston 26. The piston is connected to the tailgate box 42 via a connecting piece 51 .

In this embodiment, the body comprises two stops 50, 52, between which is intended to engage the connecting piece 51 when the tailgate is placed in closed position on the body.

Each abutment 50, 52 comprises an upper face and four lateral faces connecting the upper face to the rest of the body. Each stop 50, 52 comprises a groove 54, 56, opening on a side face and on a portion of the upper face of the stop. The groove 54 of the stop 50 opens on the face facing upwards of this stop while the groove 56 of the abutment 52 opens on the face facing downwards of this stop, the two grooves being in facing relation. The two stops 50, 52 are situated facing each other, so that the two grooves 54, 56 are aligned in a direction substantially parallel to the direction of the axis of translation of the piston when the tailgate is placed on the body. in the closed position, corresponding to the thrust axis.

The connecting piece 51 comprises a flange 58 shaped to engage in the grooves 54 and 56, whose dimensions are substantially complementary to those of the groove. This flange is located on a median part of the body of the connecting piece 51 and positioned so that it is able to engage in each of the grooves.

Thus, the body of the connecting piece, of conical shape, is in contact with the lateral face of the abutment 50, this face producing a reaction force on the connecting piece adapted to oppose the thrust of the piston. This face is normal substantially parallel to the axis of translation of the piston, corresponding to the thrust axis. In this way, the reaction force exerted by the abutment on the connecting piece opposes the thrust force. It is however likely to create in combination with the pushing force a torque causing a twisting of the connecting piece and, therefore, a poor positioning of the tailgate.

As the flange 58 is centered in each of the grooves 54, 56, the connecting piece 30 can not twist and the tailgate remains correctly positioned. A beveled shape of the edges of the flange and a corresponding shape of the groove carried by the abutment can facilitate the beginning of engagement of the flange and its holding in position.

The lateral faces of the abutments 50, 52 are of normal slightly inclined relative to the direction of the thrust axis, to ensure a better implementation of the connecting piece between the stops when closing the tailgate, without damaging the piece or one of the stops.

It is important that there is a tight clearance between the connecting piece 30 and the stop 50, so that the thrust force of the piston does not generate excessive stresses in the tailgate.

The invention is not limited to the embodiment described above.

Indeed, it is conceivable that the body comprises a stop located in the axis of translation of the piston, corresponding to the axis of thrust, when the tailgate is placed on the body in the closed position. The end of the piston is intended in this case to rest on one face of the abutment in this position. No torsional stress is transmitted to the box because the two forces are essentially collinear.

It is also possible to provide a single stop comprising a groove as described in the embodiment of the invention. figure 4 which will also have the effect of preventing twisting of the connecting piece.

In addition, the stop is not necessarily formed with the body and can be reported on the piece by gluing, welding or any other means. The shape of the abutment, the groove or the collar are not limited to those described.

The connecting piece can also be reported on the body by other means than those described.

The invention can also be implemented for a tailgate box which is shaped in a material other than a thermoplastic material, for example a thermosetting material.

Claims (7)

1. Assembly including a body (12; 49) of an automobile and a tailgate (16) mounted on the body so as to be movable between an open position and a closed position, the assembly including:

   - an opening assistance means (20, 30; 20, 51) mounted between the body and the tailgate in order to apply a pushing force on the tailgate that tends to move the latter into an open position, comprising a cylinder (20) applying a pushing force along a given axis (X) when the tailgate is placed in closed position;

   - at least one abutment (48; 50, 52) provided on the body, for applying on the opening assistance means, when the tailgate is in closed position, a force opposite to the pushing force thereof so that the tailgate is not subjected, or barely subjected, to the pushing force of the opening assistance means,

   the assembly comprising a connecting part (30; 51), preferably metallic, connecting the cylinder to the tailgate and means for centring (54, 56) the connecting part with respect to the body, when the tailgate is placed in closed position on the body, at least one of the abutments being designed so that the connecting part (30; 51) rests against the abutment (48; 50, 52) when the tailgate is placed in closed position on the body and at least one of the abutments (50, 52) comprising a groove (54, 56) in which a projection (58) of shape substantially complementary to that of the groove, fastened to the connecting part, can engage when the tailgate is placed in closed position on the body.
2. Assembly according to the preceding claim, wherein at least one surface of the abutment on which the opening assistance means may rest is normally substantially parallel to the pushing force axis (X).
3. Assembly according to any of the preceding claims, wherein at least one of the abutments is designed on the body so that at least one bearing surface of the abutment intersects the pushing force axis when the tailgate is placed in closed position on the body.
4. Assembly according to the preceding claim, wherein at least one of the abutments is designed so that one end of the cylinder rests against the abutment when the tailgate is placed in closed position on the body.
5. Assembly according to the preceding claim, wherein the projection consists of a collar (58) formed on the connecting part.
6. Assembly according to any of the preceding claims, wherein at least one abutment is formed on the body by stamping or added to the body, for example by welding.
7. Assembly according to any of the preceding claims, wherein the tailgate comprises a box made at least partially from plastic material, for example from thermoplastic material, especially reinforced thermoplastic material, such as glass fiber-reinforced polypropylene (GFRP).

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