FR2875740A1 - Motor vehicle, has multi-arm axle with longitudinal arm having sufficient elasticity to permit longitudinal movement of wheel when wheel encounters obstacle on ground, and upper transversal arms connected to hub carrier by ball joints - Google Patents

Abstract

The vehicle has a multi-arm axle (30) including a hub carrier (40) on which a wheel (20) is mounted around a wheel spindle. The axle has upper transversal arms (52, 53) connected to the carrier by ball joints. The axle has a longitudinal arm (60) that has sufficient elasticity for permitting a longitudinal movement of the wheel when the wheel encounters an obstacle on ground. A spacer controls movements of the joints along a joint pin. The arm (60) is articulated on the hub carrier around a vertical axis (611) by an end (61) and articulated on a body shell around a transversal axis (621) by another end (62).

Description

Field of the invention

  The invention relates generally to motor vehicles and suspensions for motor vehicles.

  More specifically, the invention relates to a motor vehicle comprising a body, at least one wheel resting on the ground, and a multi-link axle linking the body to the wheel, the axle comprising a hub carrier on which the wheel is rotatably mounted around a transverse wheel axle, and one or more transverse arms each articulated on one side on the hub carrier and articulated on the opposite side on the vehicle body, the axle further comprising a longitudinal arm articulated on the hub carrier around the a substantially vertical axis at a first end, and articulated on the body about a substantially transverse axis by a second end opposite to the first.

  STATE OF THE ART Vehicles of this type are known from the prior art.

  When the wheel encounters an obstacle on the ground, this wheel undergoes a force having a vertical component and a longitudinal component.

  This obstacle may be an unevenness of the ground, a stone, a hole or any other object or formation projecting or recessed from the ground.

  The vertical component is damped by the suspension of the vehicle before being transmitted to the box and is not felt very suddenly by the passengers. The longitudinal component, however, is not cushioned by the suspension and is felt as a shock by the passengers of the vehicle.

  It is known to provide that the axle allows a longitudinal displacement of the wheel center when the wheel meets an obstacle, so as to erase it and improve the feelings of passengers.

  For this purpose, we choose an axle whose kinematics imposes on the wheel center, in the event of an obstacle, a rotational movement about a transverse axis A located immediately below the base of the wheel B, that is to say say under the point of contact between the wheel and the ground, as shown in Figure 1.

  As the lever arm between the axis of rotation and the wheel center is greater than that between the axis of rotation and the wheel base, the axle may have a relatively lower stiffness in the center of the wheel and relatively stronger at the base of the wheel.

  In this context, the present invention aims to propose a new solution for guiding the longitudinal displacement of the wheel center in the event of an obstacle, and for damping the longitudinal component of the force resulting from the crossing of this obstacle by the wheel.

  OBJECT OF THE INVENTION To this end, the vehicle of the invention, moreover, conforming to the generic definition given in the preamble above, is essentially characterized in that the longitudinal arm has sufficient elasticity in the longitudinal direction. to allow longitudinal movement of the wheel when it encounters an obstacle on the ground.

  Preferably, the longitudinal arm allows the longitudinal displacement of the wheel in the two opposite directions.

  According to an advantageous characteristic of the invention, the axle comprises at least one lower transverse arm and means of articulation of an outer end of the lower arm on the hub carrier under the wheel axle about an axis of longitudinal articulation, these means comprising a sliding ball joint on the hinge axis.

  In addition, the hinge means comprise two opposite sides of the ball of the elastic shims controlling the deflection of the ball along the hinge axis.

  According to another advantageous characteristic of the invention, the longitudinal arm comprises elastic connection means of the second end of said arm on the transverse axis, these means comprising an orifice pierced transversely in said second end and traversed by the transverse axis, and an elastic shim interposed between an inner surface of the orifice and the transverse axis, the elastic wedge being transversely pierced with at least two first louvers disposed on the two opposite longitudinal sides of the transverse axis.

  The vehicle of the invention may further have one or more of the features below.

  - The orifice has, in a plane perpendicular to the transverse direction, an oblong section elongated longitudinally.

  - The first two louvers each have a section perpendicular to the transverse direction of generally arcuate concavity shape facing the transverse axis.

  - The elastic wedge is transversely pierced by at least two seconds ears disposed on the two opposite longitudinal sides of the transverse axis and extending parallel to the first two ears.

  - The wedge comprises a soul extending in a longitudinal plane and closing the first two gills in transversely central portions thereof.

  - The second end of the longitudinal arm is shaped as a ring defining the orifice.

Brief description of the figures

  Other characteristics and advantages of the invention will emerge clearly from the description which is given below, by way of indication and in no way limiting, with reference to the appended figures, among which: FIG. 1 is a schematic representation of the movement of the center wheel when it encounters an obstacle on the road, - Figure 2 is a partial perspective view of the axle of a vehicle according to the prior art, - Figure 3 is a view similar to that of the FIG. 2 is a partial top view of the axle of FIG. 2, showing the articulation of the lower transverse arm on the hub carrier, with tearing away to reveal the 5 is a view similar to that of FIG. 4 for the axle of FIG. 3; FIGS. 6A to 6C are views similar to FIG. 5, without tearing away, showing the configuration of FIG. the articulation respectiveme after pivoting the hub carrier of a first longitudinal side, at rest, and after rotation of the hub carrier with a second longitudinal side opposite the first, FIGS. 6D to 6F are views similar to FIGS. 6A to 6C, broken away. to allow the hinge axis and the ball joint to appear; FIG. 7 is a side view in a transverse direction of the longitudinal arm of the axle of FIG. 3, provided with an elastic wedge conforming to a first embodiment; FIG. 8 is a perspective view of the end of the arm of FIG. 7 carrying the shim; FIG. 9 is a side view similar to that of FIG. an elastic shim according to a second embodiment of the invention, and - Figure 10 is a perspective view of the end of the arm of Figure 9 carrying the shim, an upper half of this end n. not being shown to reveal the internal structure of the elastic wedge.

  Embodiments of the invention The motor vehicle whose axle is shown in Figure 2 conventionally comprises a box (not shown), four wheels 20 resting on the ground, and a multi-link axle 30 linking the body to two of wheels 20, either the front wheels or the rear wheels.

  The axle 30 comprises for each wheel 20 a hub carrier 40 on which the wheel 20 is rotatably mounted about a transverse wheel axis 21, a lower transverse arm 51 and two upper transverse arms 52 and 53, each transverse arm being articulated on an outer side on the hub carrier 40, and hinged on the inner side opposite the outer side on the crosspiece 10, the crossbar itself being rigidly fixed to the vehicle body.

  The upper transverse arms 52 and 53 are rigidly fixed on the crosspiece 10, and are connected by ball joints to the hub carrier 40, at two points thereof above the wheel axle 21, these two points being mutually spaced in the longitudinal direction so that the wheel axle 21 is disposed longitudinally between the two hinge points.

  The lower arm 51 is rigidly fixed to the crosspiece 10 and is articulated by an outer end 511 on the hub carrier 40, under the wheel axle 21, about a longitudinal axis of articulation 71, by means of articulation 70 which will be described later.

  The axle 30 further comprises a longitudinal arm 60 articulated on the hub carrier 40 about a substantially vertical axis 611 by a first end 61, and articulated on the body about a substantially transverse axis 621 by a second end 62 opposite to the first one.

  The first end 61 comprises a portion shaped as a stirrup 612 having two mutually spaced branches, the hub carrier 40 comprising a portion pivotally mounted in the stirrup 61 about the vertical axis 611.

  The second end 62 is articulated in a yoke 80 secured to the vehicle body around the transverse axis 621, this axis being fixed longitudinally with respect to the body.

  According to the invention, the longitudinal arm 60 has in the longitudinal direction sufficient elasticity to allow the longitudinal displacement of the wheel 20 when it encounters an obstacle on the ground.

  The longitudinal arm 60 allows longitudinal displacement of the wheel 20 in the two opposite directions, towards the front and toward the rear of the vehicle, which results in a reconciliation or a mutual distance from the first end 61 of the arm 60 and of the transverse axis 621.

  For this purpose, the longitudinal arm 60 comprises means for elastic connection of the second end 62 of said arm with the transverse axis 621 as shown in FIGS. 7 and 8. These means comprise an oblong orifice 622 pierced transversely in the second end 62 longitudinal arm 60 and traversed by the transverse axis 621, and an elastic shim 63 interposed between an inner surface 623 of the orifice 622 and the transverse axis 621.

  FIGS. 7 and 9 show that the oblong orifice 622 has, for example, a section perpendicular to the transverse axis 621 of substantially oval shape with a large longitudinal axis, the axis 621 normally occupying the center of the oval.

  Preferably, the second end 62 of the longitudinal arm 60 is shaped into a ring defining the oblong orifice 622. This ring has a large transverse width, for example substantially equal to that of the minor axis of the oval section of the oblong orifice 622 , or at half the length of the major axis of this section. It should be noted that the section of the oblong orifice 622 perpendicular to the transverse direction is constant along the orifice.

  The elastic wedge 63 is secured to an outer side of the inner surface 623 and an inner side of the transverse axis 621. It is for example glued on the inner surface 623 and on the transverse axis 621. It is extends transversely over the entire width of the oblong orifice 622.

  In order to allow longitudinal displacement of the longitudinal arm 60, the elastic shim 63 is pierced transversely by at least two first lugs 631 disposed on the two opposite longitudinal sides of the transverse axis 621.

  These first two louvers 631 each have a section perpendicular to the transverse direction of generally circular arc shape, concavity facing the transverse axis 621.

  The wedge is made of an elastic material, for example polyurethane or rubber.

  In a first embodiment, corresponding to FIGS. 7 and 8, the longitudinal displacement of the arm 60 is controlled by varying the number and size of the openings formed in the elastic shim 63.

  In the exemplary embodiment shown, the elastic shim 63 is pierced transversely, in addition to the first two lugs 631, two second ears 632 disposed on the two opposite longitudinal sides of the transverse axis 621 and extending parallel to the two first lugs 631 .

  The first louvers 631 and the second louvers 632 35 each extend at an angle of about 90, and are disposed approximately in mutually parallel transverse vertical planes. They cross the shim 63 over its entire transverse width.

  The first openings 631 are centered on the axis 621. The second openings 632 are interposed between the first openings 631 and the inner surface 623 of the oblong orifice 622.

  The longitudinal thickness of the gills 631/632 is chosen as a function of the elasticity and damping characteristics of the longitudinal movements of the wheel desired for the elastic wedge. FIGS. 7 and 8 show an exemplary embodiment in which the longitudinal thicknesses of the gills are large, such that, considered along the longitudinal direction passing through the transverse axis 621, the empty parts constitute a greater proportion of the longitudinal thickness of the wedge than the solid parts.

  When the hub carrier 40 undergoes a longitudinal force, in any of the two possible directions, the wedge 63 is compressed between the transverse axis 621 and the inner surface 623 of the orifice 622, which results in a constriction of 63 and 632. As long as the openings remain open, the displacement of the longitudinal arm 60 is possible, the ratio between the force exerted and the displacement of the arm being a function of the elasticity of the shim. When the gills are closed, the arm 60 is no longer free longitudinally, its longitudinal movements then being a function of the intrinsic elasticity of the material constituting the hold.

  The longitudinal displacement of the arm 60 is accompanied by a damping of the longitudinal force transmitted to the body.

  The elasticity and the damping capacity of the wedge are functions of the material constituting the wedge, the geometry of the wedge, the geometry of the gills. The shim may comprise more than two louvers on each longitudinal side, for example three, four or more, depending on the desired characteristics.

  In a second embodiment, corresponding to Figures 9 and 10, the shim 63 comprises a core 633 extending in a longitudinal plane and closing the first two louvers 631 in transversely central portions thereof.

  In the embodiment illustrated here, the wedge comprises only the first two openings 631. These gills each extend over an angle of about 90, and partially surround the transverse axis 621 of the two opposite longitudinal sides. They cross the shim 63 over its entire transverse width.

  The first openings 631 are approximately centered on the axis 621.

  As in the first embodiment, the longitudinal thickness of the gills 631 is chosen according to the characteristics of elasticity and damping of the longitudinal movements of the desired wheel for the elastic wedge. FIGS. 9 and 10 show an exemplary embodiment in which the longitudinal thicknesses of the gills are large, such that, considered along the longitudinal direction passing through the transverse axis 621, the empty parts constitute a greater proportion of the longitudinal thickness of the wedge than the solid parts.

  The core 633 extends in the median vertical longitudinal plane of the shim 63. This core 633 has a transverse width a small compared to the transverse width of the shim.

  As before, when the hub carrier 40 undergoes a longitudinal force, in any of the two possible directions, the shim 63 is compressed between the transverse axis 621 and the inner surface 623 of the orifice 622, which results in A constriction of the gills 631. As long as the gills remain open, the displacement of the longitudinal arm 60 is possible, the ratio between the force exerted and the movement of the arm being a function of the elasticity of the wedge. When the gills are closed, the arm 60 is no longer free longitudinally, its longitudinal movements then being a function of the intrinsic elasticity of the material constituting the hold. The longitudinal movement of the arm 60 is accompanied by damping.

  The elasticity and the damping capacity of the wedge are functions of the material constituting the wedge, the geometry of the wedge, the geometry of the gills, and the stiffness of the core 633. The wedge can comprise several souls 633 mutually parallel, distributed transversely along the gills 632, depending on the desired damping characteristics.

  So as to impose on the wheel center a rotational movement about a point A close to the base B of the wheel 20 when the wheel 20 encounters an obstacle, it is expected that the hinge means 70 of the outer end 511 of the lower arm 51 on the hub carrier 40 comprise a ball joint 72 slidably mounted on the hinge axis 71.

  More precisely, as shown in FIG. 5, the outer end 511 is shaped like a stirrup having two parallel wings 512, these wings being pierced by respective longitudinally aligned orifices receiving the articulation axis 71.

  The hub carrier 40 comprises a lower portion 41 in the form of a cylinder coaxial with the hinge pin 71, engaged between the flanges 512, having a central recess 411 of shape conjugate to that of the ball 72, this ball 72 being free mounted in rotation in the recess 411.

  The articulation means 70 further comprise two identical elastic shims 73 interposed between the ball 72 and the two wings 512, and making it possible to control the deflection of the ball 72 along the hinge axis 71 of the two opposite sides.

  Counterbores 412 are formed around the central recess 411 on opposite sides of the lower part 41, the elastic blocks 73 filling these countersinks 412 when the ball 72 moves to the corresponding wing 512. When the ball 72 is at the end of stroke, in the immediate vicinity of the wing 512, the elastic shim 72 is almost completely retracted inside the counterbore 412, as shown in Figure 6F.

  At rest, that is to say when the wheel is not displaced by an obstacle on the ground, the shims 73 exert on the ball 72 forces of the same absolute value, oriented in opposite directions, thus maintaining the ball 72 substantially in the center of the hinge axis 72.

  Note that the two wings 512 are sufficiently spaced apart so that the lower portion 41 is, at rest, located at a distance from each of the wings 512, which allows the translation of the ball 72 along the axis of articulation 71 .

  The wedges 73 have for example each of the sections perpendicular to the hinge axis 71 of increasing size from the ball 72 to the wing 512.

  The behavior of the axle can thus be modulated by acting on the material of the hold, on the length of the longitudinal shim, and on the sizes of the sections of the hold.

  As shown in FIGS. 6A to 6F, when the wheel 20 encounters an obstacle on the ground, the lower portion 41 of the hub carrier 40 undergoes a longitudinal translation of a side opposite to the direction of movement of the vehicle relative to the outer end. 511, and is jointly rotated about the ball 72 in a longitudinal vertical plane, in a direction such that the wheel center pivots on a side opposite to the direction of movement of the vehicle.

  These combined movements make it possible to obtain the desired result, that is to say a displacement of the wheel center in rotation about an axis close to the base of the wheel 20, as illustrated in FIG. 1.

  The vehicle described above can have multiple variants without departing from the scope of the invention.

  The orifice 622 may not be oval, but elliptical, round, or rectangular or have any other suitable shape. This section is preferably elongated longitudinally but may instead be elongated vertically, provided that the longitudinal length of the orifice is sufficient to provide gills in the wedge of the two longitudinal sides opposite the transverse axis.

  The gills may not have a section in a circular arc but be of vertical cross section, or any other form elongated vertically.

  The multi-link axle may comprise a single upper arm, or transverse arms positioned differently from what is shown in Figures 2 and 3.

  The axle described above may carry the front wheels of the vehicle or the rear wheels.

  It is therefore clear that the motor vehicle described above has multiple advantages.

  The elasticity of the longitudinal arm absorbs some of the shock created when the wheel meets an obstacle on the road, which improves the comfort of the passengers.

  This damping can be achieved in both possible directions of movement of the vehicle.

  In addition, the elastic wedge plays the role of filtering the vibrations created by the rolling of the wheel on the ground.

  The longitudinal arm can be made in many different ways, which makes it easy to adapt to its environment in the vehicle.

  The overall axle structure is generally not changed with respect to the prior art, so that the invention applies to virtually all vehicles with a multi-axle axle.

  The combined use of a flexible longitudinal arm and means of articulation of the transverse arm on the hub carrier with a sliding ball joint on the hinge axis make it possible to obtain optimum behavior of the vehicle in the event of an obstacle. On the ground.

Claims (10)

  A motor vehicle comprising a body, at least one wheel (20) resting on the ground, and a multi-link axle (30) linking the body to the wheel (20), the axle (30) comprising a hub carrier (40) wherein the wheel (20) is rotatably mounted about a transverse wheel axis (21), and one or more transverse arms (51, 52, 53) each hinged on one side to the hub carrier (40) and connected on the opposite side to the vehicle body, the axle (30) further comprising a longitudinal arm (60) articulated on the hub carrier (40) about a substantially vertical axis by a first end (61), and articulated on the box around a substantially transverse axis by a second end (62) opposite to the first, characterized in that the longitudinal arm (60) has in the longitudinal direction sufficient elasticity to allow the longitudinal displacement of the wheel (20) when it encounters an obstacle on the ground.   2. Motor vehicle according to claim 1, characterized in that the longitudinal arm (60) allows the longitudinal displacement of the wheel (20) in two opposite directions.   3. Motor vehicle according to claim 1 or 2, characterized in that the axle (30) comprises at least one lower transverse arm (51) and hinge means (70) of an outer end (511) of the arm lower part (51) on the hub carrier (40) under the wheel axle (21) about a longitudinal axis of articulation (71), these means comprising a ball joint (72) sliding on the hinge axis ( 71).   4. Motor vehicle according to claim 3, characterized in that the hinge means (70) comprise on two opposite sides of the ball joint (72) elastic wedges (73) controlling the movement of the ball joint (72) along of the hinge axis (71).   5. Motor vehicle according to any one of claims 1 to 4, characterized in that the longitudinal arm (60) comprises means for elastic connection of the second end (62) of said arm on the transverse axis (621), these means comprising an orifice (622) pierced transversely in said second end (62) and traversed by the transverse axis (621), and an elastic shim (63) interposed between an inner surface (623) of the orifice (622) and the transverse axis (621), the elastic shim (63) being pierced transversely with at least two first louvers (631) disposed on opposite longitudinal sides of the transverse axis (621).   6. A motor vehicle according to claim 5, characterized in that the orifice (622) has, in a plane perpendicular to the transverse direction, a longitudinally elongate oblong section.   7. Motor vehicle according to claim 5 or 6, characterized in that the first two gills (631) each have a cross section perpendicular to the transverse direction of generally concave circular arc shape facing the transverse axis (621).   8. Motor vehicle according to any one of claims 5 to 7, characterized in that the elastic wedge (63) is transversely pierced by at least two seconds ears (632) arranged on the two opposite longitudinal sides of the transverse axis ( 621) and extending parallel to the two first ears (631).   9. Motor vehicle according to any one of claims 5 to 7, characterized in that the wedge (63) comprises a core (633) extending in a longitudinal plane and closing the first two gills (631) in parts transversely central of these.   10. Motor vehicle according to any one of claims 5 to 9, characterized in that the second end (62) of the longitudinal arm (60) is shaped as a ring defining the orifice (622).