EP3655310A1

EP3655310A1 - Rear diffuser with sliding connecting rods

Info

Publication number: EP3655310A1
Application number: EP18762575.1A
Authority: EP
Inventors: Frédéric STABLO; Romain CRETIER
Original assignee: Plastic Omnium SE
Current assignee: Plastic Omnium SE
Priority date: 2017-07-20
Filing date: 2018-07-19
Publication date: 2020-05-27
Also published as: WO2019016483A1; FR3069226A1; MA49638A

Abstract

The invention concerns a rear diffuser (2) of a motor vehicle, comprising at least one movable panel (6) that can move between a deployed position and a retracted position when the rear diffuser (2) is attached to a bodywork part (4) of the motor vehicle, the rear diffuser (2) comprising a motorised mechanism capable of allowing a part of the movable panel (6), in the deployed position, to be pressed against the bodywork part (4) when the rear diffuser (2) is attached to the motor vehicle bodywork part (4).

Description

Rear diffuser with sliding rods

The invention relates to the rear diffusers of a motor vehicle and more particularly the movable rear diffusers.

The rear diffuser is a part that can be present in the rear of a motor vehicle, more precisely under the frame or in the lower part of the bumper, and for the purpose of improving the aerodynamic performance of the vehicle. It may for example be to improve the ground support of the vehicle.

Some diffusers allow them to improve the aerodynamic performance of the vehicle by reducing the drag of the vehicle, that is to say the force opposing the movement of the vehicle in the air. It is a question of shifting back the points of separation of the air with respect to the vehicle, that is to say the points at which the air does not follow the body any more. This allows to push back the depression created at the rear of the vehicle and thus limit the effect of restraint (called "suction effect") of this depression on the motor vehicle.

Current solutions, such as that described in US 2017/113741, consist of a rear diffuser comprising a movable panel rotated between a retracted position and an extended position when the vehicle is moving. The rotation of the deployed position to the retracted position makes it possible to push back the air separation points and thus reduce the drag of the motor vehicle as explained previously. The mobile panel is deployed from a certain speed to reduce vehicle drag and is folded at high speed.

However, and in order to optimally reduce the drag of the vehicle, it may be necessary to perform a significant rotational movement to sufficiently shift back the depression created at the rear of the vehicle. This significant rotational movement has the effect of strongly moving the movable panel from the rest of the motor vehicle because the movable panel is curved. As a result, the distance between the center of the mobile panel and the vehicle is important. In addition, a rotation at a large angle (but necessary to achieve the expected effect) can lead to moving the movable panel under the minimal ground clearance of the vehicle, that is to say the distance between the ground and the ground. lowest point of the chassis that should not come into contact with the ground. This passage under the ground clearance leads to a passage of the air flow above the movable panel. This passage of the airflow above the movable panel, between the movable panel and the bodywork part, leads to increase the support of the vehicle ground. However, this increase of the ground support is not a characteristic sought in this case. Worse, the ground support is characterized by the exercise of a force from the top down on the movable panel, it is difficult to retract the mobile panel or even to maintain it in a stable position. It is therefore necessary to provide a large dimensioning of the output torque of the actuator allowing the movements of the movable panel.

The aforementioned force also generates turbulence at the mobile panel when it is deployed, which creates difficulties in keeping it in position. This turbulence intensifying at high speed, it then becomes necessary to retract the movable panel at high speed using an actuator having a large output torque.

A simple rotational movement of the movable panel can also lead to damage to the movable panel, for example the appearance of scratches because of the curve of the movable panel. In other words, if the moving panel is kept too close to the vehicle, friction can occur and damage the movable panel due to its shape.

The invention aims to provide a motor vehicle rear diffuser to effectively reduce the aerodynamic drag of the motor vehicle while ensuring on the one hand a deployment and maintenance in position easy mobile panel and on the other hand the preservation of the aesthetic appearance of the diffuser.

The invention relates to a rear diffuser of a motor vehicle comprising at least one movable panel between an extended position and a retracted position when the rear diffuser is fixed to a body part of a motor vehicle, the rear diffuser comprising a motorized mechanism adapted to allow a portion of the movable panel in the deployed position to press against the body part when the rear diffuser is attached to a body part of a motor vehicle. Thus, the movable panel in the deployed position does not allow air to pass over him. This positioning makes it possible to direct the air from the underbody of the vehicle towards the lower part of the diffuser. The absence of an air passage on the upper part of the diffuser makes it possible to avoid the use of a vertical force (from top to bottom) on the deployed mobile panel, which makes it easier to retract or hold the mobile panel in position.

This orientation of the air from the base of the vehicle to the lower part of the diffuser also limits the turbulence due to possible play ("aerodynamic"), or during transitions of the diffuser position (continuity of surfaces at the scale aerodynamic).

The rear diffuser may further comprise one or more of the following features, taken alone or in combination:

- The movable panel is adapted to expand and retract in a path according to a combined movement of translation and rotation; the motorized mechanism comprises two deployment rods;

the two deployment links are connected to each other;

- The first deployment rod is able to set in motion the second deployment rod;

the movement of the second deployment rod by the first deployment rod is able to be performed by means of a connecting member comprising a pin connected to the first deployment rod and a cylinder connected to the second connecting rod. Deployment

- The pin and the cylinder are pivotally mounted relative to each other;

- The cylinder is slidably mounted along the second deployment rod, preferably via a sliding pivot type connection;

- Both deployment rods are adapted to be set in motion by an actuator adapted to allow a rectilinear actuating movement;

- The actuator is able to set in motion the first deployment rod; and

- The actuator is selected from a cylinder, a shape memory alloy actuator or a slide.

The invention also relates to a bodywork part of a motor vehicle comprising a rear diffuser according to the invention.

Advantageously, the bodywork part is a rear bumper of a motor vehicle.

We will now present an embodiment of the invention given by way of non-limiting example and with reference to the appended figures in which:

- Figure 1 shows a vehicle whose rear bumper comprises a rear diffuser according to the invention, the rear diffuser being in the retracted position;

- Figure 2 shows a vehicle whose rear bumper comprises a rear diffuser according to the invention, the rear diffuser being in the deployed position;

- Figure 3 is an enlargement of a motorized mechanism for deployment and retraction of the movable panel of the rear diffuser according to the invention, the motorized mechanism being in a configuration corresponding to the movable panel in the retracted position;

- Figure 4 is an enlargement of a motorized mechanism for deployment and retraction of the movable panel of the rear diffuser according to the invention, the motorized mechanism being in a configuration corresponding to the movable panel during deployment or retraction; and

FIG. 5 is an enlargement of a motorized mechanism for deploying and retracting the movable panel of the rear diffuser according to the invention, the motorized mechanism being in a configuration corresponding to the movable panel in FIG. deployed position.

The figures show a rear diffuser in its configuration mounted on a body part of a motor vehicle, specifically a rear bumper of a motor vehicle.

Subsequently, the terms such as "longitudinal axis X", "transverse axis Y", "vertical axis Z", "front", "rear", "above", "upper", "below", "Lower", etc. are understood by reference to the usual orientation of motor vehicles according to the reference shown in Figure 1 for example.

The figures illustrate a rear diffuser 2 of a motor vehicle, for example made of plastic, mounted on a rear bumper 4, for example also made of plastic, and comprising at least one movable panel 6 between an extended position and a retracted position when the rear diffuser 2 is fixed on a rear bumper 4 of a motor vehicle, the rear diffuser 2 comprising a motorized mechanism adapted to allow a portion of the movable panel 6 in the deployed position to press against the body part 4 , here the rear bumper, when the rear diffuser 2 is fixed on the rear bumper 4. The rear diffuser 2 may also comprise a fixed part, for example a frame fixed to the rear bumper 4, not shown on the FIGS.

The rear diffuser 2 is therefore able to pass from a retracted position shown in FIG. 1, in which the movable panel 6 can be pressed against the rear bumper 4, in an extended position, in which a lower end 8 of the movable panel 6 is pressed under the rear bumper 4, more precisely under the lower line of the vehicle corresponding to the line of separation of the air flow of the rear bumper 4. This configuration in the deployed position can prevent the air to pass above the movable panel which avoids the formation of support in a direction parallel to a vertical axis Z while allowing to reduce the aerodynamic drag by pushing back the points of separation of the flow of 'air.

It is possible to maintain a distance of about 1 to 2 centimeters between the rear bumper 4 and the movable panel 6 in the retracted position to provide a space for containing dirt, which could be deposited when the movable panel 6 is in the deployed position, and without hindering the motorized mechanism.

The movable panel 6 is therefore able, thanks to a trajectory following a combined movement of translation and rotation, to depart at first from the rear bumper 4 and then to pass under the skirt of the motor vehicle so that the end 8 of the movable panel 6 is pressed under the rear bumper 4. The trajectory of the movable panel 6 allows it to move away from the vehicle before pressing against the latter which avoids damaging the movable panel 6 to cause of possible friction. The rear diffuser 2 comprises in the example illustrated in FIGS. 1 and 2 two motorized mechanisms able to deploy and retract the movable panel 6. Each motorized mechanism comprises a first deployment rod 10 and a second deployment rod 12.

In the example shown in Figures 3 to 5, the first deployment rod 10 has a first end 13 connected to the movable panel 6 and a second end 14 connected to the actuator 16. It should be noted that the actuator itself speak is not shown in the figures, the reference 16 designating the location of this actuator. For a question of readability, we will speak later of "actuator 16". These two ends are pivotally mounted relative to the means to which they are connected. The second deployment rod 12 has a first end 18 connected to the movable panel 6 and a second end 20 connected to the rear bumper 4 (the end 20 can also be connected to any other fixed part of the vehicle, the chassis, such as the fixed part of the rear diffuser 2). The end 20 is pivotally mounted relative to the rear bumper 4 (or the fixed part of the rear diffuser 2) and the end 18 is also pivotally mounted relative to the movable panel 6. The two deployment rods 10 and 12 are connected to one another by means of a connecting member 22 composed of a fixed pin 26 on the first deployment rod 10 and a cylinder 24 carried by the second deployment rod 12. cylinder 24 is slidable on the second connecting rod 12 and advantageously sliding pivot with this second connecting rod 12 to allow to slide correctly even if there is a slight clearance between the parts. The pin 26 and the cylinder 24 are pivoted relative to each other. This connection allows the second deployment rod 12 to be moved by the first deployment rod 10 itself set in motion by the actuator 16.

We have described an exemplary embodiment in which the ends 13 and 14 are pivotally mounted relative to the means to which they are connected. It would not depart from the scope of the invention, if at least one of the ends 13 and 14 was connected by a ball joint to the means to which they are connected. It is the same for the end 18 which can also be connected by a ball joint connection to the movable panel 6

The actuator 16 may itself be chosen from a cylinder, a shape memory alloy actuator (that is to say an actuator composed of an alloy having the following properties: the ability to store a shape initial and return even after deformation, the possibility of alternating between two forms previously stored when its temperature varies around a critical temperature, and a superelastic behavior allowing elongations without permanent deformation higher than those of other metals) or still a classic slide. In general, this actuator 16 may be able to allow movement rectilinear actuation. This reduces the bulk, mainly in a direction parallel to a longitudinal axis X of the vehicle, since the deployment and retraction of the movable panel 6 by a combined movement of translation and rotation can be achieved by an actuator such as a jack which can be positioned to effect thrust in a direction perpendicular to the longitudinal axis X and deployment rods 10 and 12 which, when the movable panel is in the retracted position, occupy a small space in a direction parallel to the longitudinal axis X.

In the example in the figures, the actuator 16 (which may for example be a jack) makes movements in a direction parallel to the vertical axis Z of the vehicle, which reduces the space requirement in a direction parallel to an axis longitudinal X of the vehicle. It is possible to ensure this reduction in size by using a mobile actuator only in translation. This is for example the case of a cylinder.

During deployment of the movable panel 6, the actuator 16 is activated (the activation mechanism of the actuator 16 is not shown). We will describe an example in which the actuator 16 is a jack. The jack actuated will exert a thrust from top to bottom, in the example illustrated in the figures, in a direction parallel to a vertical axis Z of the motor vehicle.

This thrust has the effect of lowering the first deployment rod 10 by exerting a force on its end 14. The first deployment rod 10 will then pivot around these ends 14 and 16 which allows an output of the movable panel 6 in directions parallel to the longitudinal axis X of the vehicle but also in a direction parallel to the vertical axis Z of the motor vehicle. The various swivelings made by the first deployment rod 10 are observed in FIGS. 4 and 5.

During its displacement, the first deployment rod 10 drives the second deployment rod 12 through the connecting member 22, as can be seen in FIG. 4. In this case, and because of the change of position of the first rod 10, the pin 26, which is fixed on the first rod 10, also changes position. The cylinder 24 is then driven in turn via the pivot connection between it and the pin 26. By changing position, the cylinder 24 drives the second connecting rod 12 and the end 18 then changes position, which therefore imposes a movement to the movable panel 6. The cylinder 24 is sliding along the second link and advantageously in sliding pivot to allow it to slide correctly even if there is a slight clearance between the parts. In other words, the two deployment rods 10 and 12 are slidable relative to each other, the displacement of the second deployment rod 12 also affecting the movement of the first deployment rod 10. The second deployment rod 12 will then pivot around its second end 20 as is visible in Figures 4 and 5 to position, in the example shown in Figure 5, in a position parallel to the longitudinal axis X of the vehicle. This movement makes it possible to pivot the movable panel 6 in addition to the movements described above. The movements imposed by the two deployment rods 10 and 12 lead to a movement of the movable panel 6 describing an ellipse portion. This movement allows the movable panel 6 out of the profile of the vehicle (remaining close to the latter to limit the air passing between the vehicle and the movable panel 6) and then to press against the lower line of the latter. The upper end 28 of the movable panel 6 is strongly away from the vehicle in a direction parallel to the longitudinal axis X while the lower end 8 is pressed under the low line of the vehicle.

Upon retraction of the movable panel 6, the actuator performs a movement opposite to that performed during deployment, resulting in the first deployment rod 10 which will itself lead to the second deployment rod 12. The two deployment rods return at their respective initial positions (visible in Figure 3) which allowed to retract the movable panel 6 so that the latter occupies the position illustrated in Figure 1.

The invention is not limited to the embodiments presented and other embodiments will become apparent to those skilled in the art.

It is possible in particular that the deployment rods have different amplitude of strokes so that the deployed position of the movable panel is different in terms of inclination vis-à-vis the rear bumper.

Nomenclature

: rear diffuser

: rear bumper

: mobile panel

: low end of the mobile panel

: first deployment link

: second deployment link

: first end of the first deployment link: second end of the first deployment link: actuator

: first end of the second deployment link: second end of the second deployment link: link

: cylinder of the second connecting rod

: pawn of the first deployment rod

: high end of the mobile panel

Claims

claims

1. Rear diffuser (2) of a motor vehicle characterized in that it comprises at least one movable panel (6) between an extended position and a retracted position when the rear diffuser (2) is fixed on a bodywork part (4) of a motor vehicle,

the rear diffuser (2) comprising a motorized mechanism adapted to allow a portion of the movable panel (2) in the extended position to press against the body part (4) when the rear diffuser (2) is fixed on the body part (4) motor vehicle.

2. rear diffuser (2) according to the preceding claim, wherein the movable panel (6) is adapted to expand and retract in a path according to a combined movement of translation and rotation.

A rear diffuser (2) according to any one of the preceding claims, wherein the motorized mechanism comprises two deployment rods (10, 12).

4. rear diffuser (2) according to claim 3, wherein the two deployment rods (10, 12) are connected to each other.

5. rear diffuser (2) according to any one of claims 3 and 4, wherein the first deployment rod (10) is adapted to set in motion the second deployment rod (12).

6. rear diffuser (2) according to the preceding claim, wherein the setting in motion of the second deployment rod (12) by the first deployment rod (10) is adapted to be performed via a body of link (22) comprising a pin (26) connected to the first deployment link (10) and a cylinder (24) connected to the second deployment link (12).

7. rear diffuser (2) according to the preceding claim, wherein the pin (26) and the cylinder (24) are pivotally mounted relative to each other.

A rear diffuser (2) according to any of claims 6 and 7, wherein the cylinder (24) is slidably mounted along the second deployment link (12), preferably via a link sliding pivot type.

9. rear diffuser (2) according to any one of claims 3 to 8, wherein the two deployment rods (10, 12) are adapted to be set in motion by an actuator (16) adapted to allow a movement of rectilinear actuation.

10. Rear diffuser (2) according to the preceding claim, wherein the actuator (16) is adapted to set in motion the first deployment rod (10).

1 1. Rear diffuser (2) according to any one of claims 9 and 10, in wherein the actuator (16) is selected from a cylinder, a shape memory alloy actuator or a slider.

12. Vehicle body part comprising a rear diffuser (2) according to any one of the preceding claims.

13. Bodywork part according to the preceding claim, the bodywork part being a rear bumper (4) of a motor vehicle.