FR3028452A1 - PERMANENT MAGNET STOPPER DEVICE FOR SUSPENSION OF A MOTOR VEHICLE - Google Patents

Abstract

The invention relates to a stop device (2) for a motor vehicle suspension, said device comprising an elastically deformable element (4) made of elastomer material, a first magnetic dipole (6) fixed to the deformable element (4), and a second magnetic dipole (8) adapted to be fixed to the suspension and configured to present to the first dipole (6) an identical magnetic pole (10) so as to generate a progressive repulsive force between the first (6) and second (8) ) dipoles getting closer. The invention also relates to a vehicle comprising such an abutment device (2). The invention also relates to a suspension damper for a motor vehicle comprising a tubular body, a rod with a piston sliding in the body and such a stop device (2).

Description

The invention relates to the field of motor vehicle suspension. BACKGROUND OF THE INVENTION More particularly, the invention relates to the field of damping of the suspension.

The suspension of a motor vehicle comprises spring elements and dampers to limit the oscillations of moving parts of the suspension. It is known to provide on the suspensions compression end stops, commonly referred to as "attacking stops". These stops have the effect of producing increased local damping during the ascent of the vehicle wheels close to their end positions. It is known to make these abutments elastomeric material. These stops are generally performed to generate progressive increased damping. The realization of such an abutment however requires that it is of a substantially significant length and a shape gradually refined on the front of the abutment, commonly called "stopper nose". Its application in a damper, however, impacts the maximum stroke of the damper; moreover, its application on a suspension arm impacts its efficiency, its progressivity of shape making it fragile and possibly leading to the buckling of the stop nose. The object of the invention is to propose a solution that overcomes at least one of the abovementioned disadvantages of the state of the art. More particularly, the invention aims to provide a suspension stop more compact and reliable. The invention relates to a stop device for a motor vehicle suspension, said device comprising: an elastically deformable element made of elastomeric material; remarkable in that it further comprises: a first magnetic dipole attached to the deformable element; and a second magnetic dipole to be attached to the suspension and configured to present to the first dipole an identical magnetic pole so as to generate a progressive repulsive force between the first and second closer dipoles.

The stop device is able to operate in two modes of operation, the first, where the dipoles are at a distance from each other, generating a progressive repulsive effort, and the second, where the dipoles are in contact, with the compression of the elastically deformable element. Advantageously, the abutment device is configured in that the force law has, in the transient mode, between the first and second modes of operation, a stress discontinuity of less than 5%, preferably less than 1%, preferably even lower. at 0.1%. According to an advantageous embodiment of the invention, the elastically deformable element comprises a front surface intended to be directed towards the suspension, and a main direction of deformation, the first dipole being disposed on a half, preferably a quarter, in said direction, of the deformable member and including the front surface. According to an advantageous embodiment of the invention, the elastically deformable element comprises a mounting surface and a main deformation direction, preferably generally perpendicular to said surface, the first dipole being at a distance from said surface of more than half of the length of the element in the main direction. According to an advantageous embodiment of the invention, the length of the first dipole in the main direction is less than 40%, preferably 30%, of the length of the elastically deformable element. According to an advantageous embodiment of the invention the elastically deformable element 20 comprises a contact surface with the suspension, the first dipole being embedded in said element at a distance from said contact surface. According to an advantageous embodiment of the invention, the first and / or second dipole is / are permanent magnet (s), preferably in neodymium. According to an advantageous embodiment of the invention, the progressive repulsive force between the first and second approaching dipoles reaches a maximum value of between 20daN and 100daN, preferably between 50daN and 80daN. According to an advantageous embodiment of the invention, the elastically deformable element is an elastomer shaped by molding, the first dipole being an insert fixed to the elastically deformable element during said molding.

According to an advantageous embodiment of the invention, the elastically deformable element, the first dipole and the second dipole comprise a central passage for a damper rod. The invention also relates to a motor vehicle comprising: a body structure; at least one mobile suspension element of a wheel; a stop device of the suspension element with respect to the structure; remarkable in that the stop device is in accordance with the invention, the elastically deformable element being mounted on the structure and the second dipole being mounted on the movable suspension element.

According to an advantageous embodiment of the invention, the mobile suspension element of a wheel is a suspension arm. The invention also relates to a suspension damper for a motor vehicle comprising: a tubular body; a rod with a piston sliding in the body; a stop device; remarkable in that the stop device 15 is in accordance with the invention, the elastically deformable element being fixed to the rod and the second dipole being fixed to the body. Advantageously, the elastically deformable element is fixed to the rod via the mounting surface of said elastically deformable element. According to an advantageous embodiment of the invention, the tubular body comprises a cap housing the second magnetic dipole, said cap being able to come into contact with the elastically deformable element and / or the first dipole after a phase of approach with repulsion force of the first and second magnetic dipoles. The measures of the invention are interesting in that the abutment device 25 according to the invention facilitates the achievement of quality of a motor vehicle suspension comprising such a device. Indeed, in case of recovery of the movable member of the suspension, a progressive repulsive effort at a distance is generated between the magnetic dipoles. This repellent effort is contactless and therefore very reliable; the application of such a stop is therefore advantageous on an oscillating arm. The stop 30 furthermore comprises an elastically deformable element which can be substantially short in its main direction, which favors its application in a suspension damper. The stop is finally configured so that the transient mode between the remote operating mode and the operating mode by contact with the elastically deformable element does not generate any noticeable shock by the driver.

Other features and advantages of the present invention will be better understood with the aid of the description and the drawings, in which: FIG. 1 is a sectional view of a stop device for a motor vehicle suspension in accordance with FIG. invention; FIG. 2 is a graph representing the force law obtained with the stop device 10 of FIG. 1; - Figure 3 is a simplified sectional view of a vehicle suspension comprising the stop device of Figure 1; - Figure 4 is a simplified sectional view of a motor vehicle suspension damper comprising the stop device of Figure 1; Figure 1 is a sectional view of a stop device 2 for a motor vehicle suspension and according to the invention. The abutment device 2 comprises a resiliently deformable element 4 on which is fixed a first magnetic dipole 6. The device 2 also comprises a second magnetic dipole 8 intended to be fixed to the suspension of the vehicle, the second dipole 8 being configured to present at the first dipole 6 a magnetic pole 10 identical, that is to say of the same nature (north / north or south / south), pole 11 vis-à-vis the first dipole so as to generate a progressive repulsive effort between the first and second dipoles 6 and 8 approaching. This phenomenon of the gradual repulsion of two magnets with which two identical poles are approached is well known to those skilled in the art. The stop device 2 is able to operate in two modes of operation, the first at a distance with the two dipoles 6 and 8 generating a progressive repulsive force, and the second by contact with the compression of the elastically deformable element 4. The resiliently deformable member 4 comprises a front surface 12 intended to be directed towards the suspension, more particularly towards a movable member of the suspension, as well as a mounting surface 14 opposite the front surface 12, the element 4 being elastically deformable according to a main direction "D" deformation. The first dipole 6 is disposed on a front portion 16 of the element 4, that is to say a portion located at or near the front surface. The front portion 16 may correspond to half, preferably to a quarter of the deformable element comprising the front surface 12 and in the main direction "D" of deformation. The main direction "D" deformation may be generally perpendicular to the mounting surface 14, and the first dipole 6 may be at a distance from the mounting surface 14 more than half the length "L" of the element following the main direction in the uncompressed state. The length of the first dipole 6 in the main direction is less than 40%, preferably 30%, of the length "L" of the elastically deformable element; it is shown embedded in the elastically deformable element 4, away from the front surface 12 of contact. This measurement is advantageous for protecting the magnetic poles 10 and 11 of the respective dipoles 8 and 6. The elastically deformable element 4 and the dipoles may be of cylindrical shape and they may have a central passage 17; we will see in connection with Figure 4 an application of the stop device 2 taking advantage of this central passage. The dipoles 6 and 8 in the image do not present in this case a central passage. The first and / or second dipoles 6 and / or 8 of the stop device 2 are permanent magnets, preferably neodymium.

In an alternative embodiment (not shown), the magnetic dipoles or at least one of the two dipoles may be a solenoid to be electrically powered. The elastically deformable element 4 is an elastomer that can be molded, the first dipole 6 can then be an insert attached to the element 4 elastically deformable during molding.

FIG. 2 is a graph showing the force law obtained with the stop device according to the invention. The force law of the abutment device has a first portion of the force curve, in bold lines on the image, for a "close-up" stroke corresponding to a low load on the abutment; at this low stress, the stop responds with a repulsive force at a distance between the magnetic dipoles. The force law of the device also has a second portion of stress curve, in fine lines on the image, for a "compression" stroke where the dipole of the suspension is in contact with the deformable element; the "compression" stroke corresponding to a strong stress on the stop. On this second portion of the force law, the stop responds by a compressive force of the elastically deformable element. One can speak of a transient mode of operation when the stop device is at a stroke "C" at the transition between the first and second portions of the force curve. The stop device is configured so that in the transient mode, a force discontinuity transmitted by the stop device is less than 5%, preferably less than 1%, more preferably less than 0.1%. The low force discontinuity, favorably the absence of stress discontinuity, as shown in the graph promotes the comfort of the damping of the stop device. The stop device 10 operates mainly under low loads, the repulsive force at a distance is then favorable to an absence of wear under such stresses. The repulsive force at a distance is progressive, it can reach near the contact in the race "C", a value between 20daN and 100daN, preferably between 50daN and 80daN. The first and second dipoles are capable of generating a repulsive force up to a given maximum distance, for example a maximum distance of between 80 mm and 120 mm, the repulsive force then being minimum at such a maximum distance. Figures 3 and 4 show two particular applications of the stop device according to the invention within suspension 22 and 26 of a motor vehicle.

FIG. 3 is a simplified view of a vehicle 18 comprising a suspension 20 connected to the structure 22 of the vehicle, the suspension comprising a stop device 2 according to the invention. The suspension 20 comprises a movable element 24 mounted to a wheel; the movable element 24 is in this case a suspension arm. The elastically deformable element 4 is mounted to the structure 22 of the vehicle by its mounting face 14. It can be seen the first dipole 6 inserted in the elastically deformable element 4. The second dipole 8 is mounted on the movable element 24 the suspension 20, vis-à-vis the first dipole 6. The movable element 24, in its phase of approaching the structure 22 of the vehicle, is braked at a distance by the repulsive forces between the dipoles 6 and 8; the movable element 24 is also braked after contact with the elastically deformable element 4, by compression of the deformable element.

Figure 4 is a simplified view of a vehicle 19 according to the invention comprising a suspension 21 connected to the structure 23 of the vehicle. The suspension 21 comprises a damper 26 according to the invention, said damper comprising a stop device 2 according to the invention. The damper 26 comprises a body 28 5 of tubular form connected to a wheel (shown in dotted lines), a rod 30 with a piston 32 sliding in the body 28, and the stop device 2. The piston 32 is located at a first end of the rod 30, the latter also comprising at a second end of the fastening means (not shown) to the structure 23 of the vehicle. The resiliently deformable element 4 of the stop device 2 comprises a central passage as shown in the first figure, passage through which it is mounted to the rod. The element 4 is in this case fixed to the structure 23 of the vehicle. by its mounting face 14. The first dipole 6 is inserted into the element 4, it also includes a central passage for receiving the rod 30. The second dipole 8 is fixed to the body 28 and also comprises a central passage to receive the Rod 30.0n can be seen in the image that the body 28 of tubular shape comprises a cap 34 housing the second dipole 8, the cap 34 being adapted to come into contact with the elastically deformable element 4 after the phase of bringing the two together. dipoles 6 and 8. A progressive repulsion effort occurs between the first and second magnetic dipoles 6 and 8 at this approximation. In an alternative embodiment (not shown), the first dipole 6 may not be embedded in the elastically deformable element 4 and be able to be in contact with the cap 34 after the approach phase. 25

Claims (10)

REVENDICATIONS1. Stopper device (2) for suspension (20; 21) of a motor vehicle (18; 19), said device comprising: - an elastically deformable element (4) made of elastomer material; characterized in that it further comprises: - a first magnetic dipole (6) fixed to the deformable element (4); and a second magnetic dipole (8) intended to be fixed to the suspension (20; 21) and configured to present to the first dipole (6) an identical magnetic pole (10) so as to generate a progressive repulsive force between the first (6; 6) and second (8) dipoles getting closer. 2. stop device (2) according to claim 1, characterized in that the elastically deformable element (4) comprises a front surface (12) intended to be directed towards the suspension (20; 21), and a main direction ( D), the first dipole (6) being disposed on a half, preferably a quarter, in said direction (D), of the deformable element (4) comprising the front surface (12). 3. stop device (2) according to one of claims 1 and 2, characterized in that the element (4) elastically deformable comprises a mounting surface (14) and a main direction (D) of deformation, preferably generally perpendicular to said surface (14), the first dipole (6) being at a distance from said surface (14) by more than half the length (L) of the element (4) in the main direction (D). 4. Stop device (2) according to one of claims 1 to 3, characterized in that the elastically deformable element (4) comprises a contact surface (12) with the suspension (20; 21), the first dipole (6) being embedded in said element (4) away from said contact surface (12). 5. stop device (2) according to one of claims 1 to 4, characterized in that the first (6) and / or the second (8) dipole is / are permanent magnet (s) , preferably in neodymium. 3028452 9 Stop device (2) according to one of claims 1 to 5, characterized in that the deformable element (4), the first dipole (6) and the second dipole (8) comprise a central passage (17). for a damper rod (30) (26). A motor vehicle (18) comprising: - a body structure (22; 23); - at least one movable member (24; 28) for suspending (20; 21) a wheel; - a stop device (2) of the suspension element (20; 21) relative to the structure (22; 23); characterized in that the abutment device (2) is according to one of claims 1 to 6, the elastically deformable member (4) being mounted on the structure (22; 23) and the second dipole (8) being mounted on the movable suspension member (24; 28) (20; 21). 8. Motor vehicle (18) according to claim 7, characterized in that the movable member (24) for suspending a wheel is a suspension arm. 9. Shock absorber (26) suspension (21) for a motor vehicle (19) comprising: - a body (28) of tubular form; - a rod (30) with a piston (32) sliding in the body (28); An abutment device (2); characterized in that the abutment device (2) is according to one of claims 1 to 6, the elastically deformable element (4) being fixed to the rod (30) and the second dipole (8) being fixed to the body (28). 10. Absorber (26) according to claim 9, characterized in that the body (28) 25 of tubular shape comprises a cap (34) housing the second magnetic dipole (8), said cap being adapted to come into contact with the element (4) elastically deformable and / or the first dipole (6) after a phase of approximation with repulsive force of the first (6) and second (8) magnetic dipoles.