FR2839280A1 - IMPROVED SUSPENSION FOR TERRESTRIAL VEHICLE - Google Patents

Abstract

This suspension, for land vehicle provided with a chassis and independent wheels, comprises, for at least one wheel (4), both at least one oscillating arm (12) articulated on a rocket (8) of the wheel and connecting the wheel to the chassis (2), and means for fixing said oscillating arm to said wheel and said chassis. These fastening means comprise, for at least a first swinging arm (12), two bars (14, 16), a first end of each bar being articulated with respect to the frame (2) and a second end of each bar being articulated on the oscillating arm, and means (34, 36) for driving in relative rotation of said first ends of the bars (14, 16). In addition, on the one hand, the spacing between the frame (2) and the axis (22) of articulation of a first (14) of the two bars (14, 16) on the oscillating arm (12), and on the other hand the position, along the swing arm (12), of the axis (28) of articulation of the second (16) of said two bars on said swing arm are variable so as to maintain the spacing substantially constant (E) between the wheel (4) and the chassis (2).

Description

The present invention relates to a suspension for land vehicle

  provided with a frame and independent wheels, in particular for a motor vehicle or for a motorcycle, of the type comprising, for at least one wheel, at least one swing arm of fixed length, which is articulated on a spindle of the wheel and which connects the wheel to the chassis, and

  means for fixing to said arm on said wheel and said chassis.

  Such wind suspensions commonly used on automobiles with independent wheels, that is to say automobiles whose suspension means specific to each of the independent wind wheels or mechanically from each other. Such a design ensures high levels of comfort and handling when moving the vehicle on

floor.

  Various arrangements of this type of suspension have been proposed in the past, relate either to the tire of the wheels, or to the means of connection of the wheels to the chassis of the vehicle. When these means include a suspension arm connecting a wheel to the chassis, it is common to produce a cited oscillating suspension >> in which the arm is connected on the one hand to the chassis by a first axis of articulation, and on the other share a wheel spindle by a second axis of articulation. Provided with a spring or a hydraulic shock absorber, this swing arm structure is thus

  even to absorb shocks due to uneven ground.

  However, such a swinging arm is by construction of fixed length, so that when the height of the chassis relative to the ground varies, for example when the vehicle is heavily loaded or when, by effect of inertia in bending, the weight distribution eral of the vehicle is transversely and longitudinally asymmetrical, the wheel is subjected to a transverse or longitudinal displacement on the ground of a few

  millimeters from its initial mean position.

  In other words, the oscillation of the arm induces a variation of o the transverse or longitudinal spacing between the wheel and the chassis (therefore a variation of the width of the fly, i.e. the distance separating a padre of wheels of the same axle for an automobile, or else a variation in the wheelbase, that is to say the distance separating the two wheels for a motorcycle), the wheel substantially describing an arc of

  circle in a plane transverse or longitudinal to the vehicle.

  These transverse or longitudinal deflections induce strong mechanical stresses, in particular at the level of the tire of the wheels, as well as an imbalance of the vehicle. The object of the invention is to provide a suspension of the type defined above, which, although of simple design, limits the transverse and / or longitudinal deflections of the wheel relative to the chassis when the height of the latter varies, or even imposes has this wheel to stay in a

  o fixed position relative to the chassis.

  To this end, the invention relates to a suspension of the precise type, in which said fixing means comprise, for at least one first swinging arm, two bars, a first end of each bar being articulated with respect to the chassis and a second end of each bar being articulated on the oscillating arm, and means for relative drive of said first ends of the bars in rotation about their axis of articulation relative to the chassis, and in which on the one hand the spacing between the chassis and the axis of articulation of a first of the two bars on the swing arm, and on the other hand the position, along the swing arm, of the axis of articulation of the second of said two bars variable wind fa , con to maintain substantially constant the spacing between the

wheel and chassis.

  According to other characteristics of this suspension, taken in isolation or in any technically possible combination: - the hinge axis of the second of the two bars on the swing arm is guided in translation along said swing arm; - A longitudinal groove for guiding the articulation axis of the second of the two bars on the swinging arm is formed in the swinging arm; n / a - the relative rotation drive means of said first ends of the two bars each comprise a gear whose two teeth wind in engagement with each other, each axis of said gears correspond to an axis of articulation of said first ends by relation to the chassis; the gear ratio of the teeth of the gears is greater than 1; said first ends of the two wind bars articulated directly on the chassis; - Said fixing means comprise a support plate on which wind articulated said first ends of the two bars, and in that one of the two bars is provided in its current part with a pivot axis o on the chassis; - It comprises a second swinging arm, and in that the means for fixing to said second arm include both a third bar articulated on the second swinging arm and substantially parallel to one of the first and second bars of the means for fixing the first swing arm, and means for transmitting movement from said first or second bar to said third bar; - The transmission means comprise a link articulated on said first or second bar and on said third bar; - The means for fixing the first and second oscillating arms o comprise a support plate on which wind both articulated said first ends of the first and second bars and one end of said third bar, and in that each of the parallel bars at

  the other has a pivot pin on the chassis.

  The invention will be better understood on reading the description which will

  follow, given only by way of example, and made with reference to the drawings in which: - Figure 1 is a schematic cross-sectional view of a side part of a motor vehicle fitted with a suspension according to the invention ; o - Figure 2 is a view similar to Figure 1, of the same vehicle as that of Figure 1, the height of the chassis relative to the ground being reduced compared to that shown in Figure 1; - Figure 3 is a view similar to that of Figure 1, of a second embodiment of a suspension according to the invention; and - Figure 4 is a schematic view of a variant of the second mode

Figure 3.

  s In FIG. 1 is shown schematically the free franc of a motor vehicle 1 of which is visible a part of the chassis 2 and a left wheel 4. The wheel is provided with a tire 6 and a spindle or hub carrier 8 partially sketches. The wheel resting on the ground S is horizontally, distant from the chassis by a spacing noted E (relative to a vertical or arbitrary plane). A suspension 10 connects the wheel 4 to the chassis 2 and essentially comprises a suspension arm 12 and two connecting bars 14 and 16

from the arm to the chassis.

  The suspension 10 also comprises in a conventional manner one or more damping members 18, such as springs or hydraulic shock absorbers, arranged between on the one hand the chassis and on the other hand the wheel 4 or the arm 12, and represented schematically by a single member 18 in FIG. 1. These damping members 18 are suitable for imposing on the chassis 2 a height of equilibrium relative to the ground S for o given conditions of loading and displacement of the chassis and for a state gives the surface of the ground on which the wheel rests. These damping members being known in themselves, they will not be

further details.

  One end of the arm 12 is articulated on the wheel spindle 8 about an axis 20. Its other end is articulated on a first end of the first bar 14, around an axis 22. The length of the arm is ie the distance between the axes 20 and 22, is fixed due to the rigidity of the oscillating arm 12, and is denoted L. The arm 12 is provided in its current part with a longitudinal through groove 26, at l inside of which an articulated pawn is received

  28 fixed on one end of the second bar 16.

  The two bars 14 and 16 are articulated on the chassis 2 at one of their ends, around axes 30 and 32 respectively. The centers of these bars, that is to say the distance between the axes 22 and 30 for bar 14, and the distance between axes 28 and 32 for bar 16, wind notes A and B respectively. In operation, these centers A and B are fixed. In addition, when the chassis is in the position of FIG. 1, the axis 22 is horizontally distant from the chassis 2 by a spacing note D, and the axis 28 is distant from the axis 20 by a spacing note F In addition, each axis 30, 32 is provided with a pigeon 34, 36, the two pigeons being engaged with each other so as to actively maintain the structure in equilibrium. These pigeons are more suitable for ensuring that the pivoting of one of the bars 14, 16 around its axis 30, 32 causes the pivoting, in the opposite direction, by gearing of them pig eons, of the other bar 16, 14 around its axis 32, 30. The gear ratio of these pigeons is chosen so that the transmission of the pivoting from one of the bars to the other induces a non-zero angular difference. More precisely, by fixing as the rest position of the system the position in which the arm 12 and the bars 14 and 16 are aligned, for example substantially horizontally, the displacement of the bar 16 can be represented by a leading angle that forms this bar relative to its o rest position; as a function of the gear ratio of the pigeons 34 and 36, the bar 14 pivots about the axis 30 by a small angle of value linked to the value of the leading angle. In other words, by calling angle differentael the difference between ['angle led formed by the bar 14 and [' angle leading formed by the bar 16, the gear ratio imposes a value

  determined from this different angle.

  In the example shown, the gear ratio of the pigs 34

and 36 is greater than 1.

  As will be better understood below, this wind on the one hand the fixed values of the centers A and B. and on the other hand the values taken by o ['angle differentael which determining [' amplitude of the correction carried out by

suspension 1.

  The operation of the suspension 10 of the invention is as follows.

  In Figure 2 is shown the vehicle 1 with the chassis 2 closer to the ground than in Figure 1, the location of the chfissis 2 and the suspension 10 as in Figure 1 being shown in Figure 2 in phantom. Such an approximation of the chassis is, for example, due to an increase in the weight of the vehicle (for example when a new passenger is mounted), when the vehicle moves in a curve to the left, inducing an inertia overweight on the left part of the vehicle, evou the presence of a bump on the ground on the path of the wheel 4. In all cases, this amounts to working the suspension 10 by deformation of its

  o structure and use of its amortization bodies 18.

  More precisely, the movement bringing the chassis closer to the ground S causes the oscillation of the arm 12 around its axis 20 of articulation on the wheel spindle 8, so that the axis 22 substantially describes an arc of a circle. radius L center on the axis 20. Being, on the one hand, the axis 28 connecting the bar 16 to the arm 12, re, cu and guide by the groove 26, approaches the ground S. and on the other hand, the pigeons 34 and 36 mesh in a way, con to entrain pivotally the bar 14 around the axis 30. As explained above, the gear ratio imposes the value of the 'different angle between the formed angles by bars 14 and 16 by

relative to a rest position.

  These joint movements of the bars 14 and 16 cause both the variation in the horizontal distance of the axis 22 relative to the frame 2, which changes from the value D (FIG. 1) to D '(FIG. 2), and the center distance variation

  axes 28 and 20, which goes from the value F (Figure 1) to F '(Figure 2).

  During all the deformation of the structure of the suspension 10, the damping member 18 and the cooperation of the pigeons 34 and 36

  ensure substantially vertical balance between the chassis 2 and the wheel 4.

  This amounts to saying that, between FIGS. 1 and 2, only the horizontal distance of the axis 22 relative to the chassis 2, and the position, along the oscillating arm 12 of the axis 28 have varied in fa, con that the variation in the distance E of the wheel relative to the chassis remains limited, or even practically zero as shown. The transverse movements of the wheel 4 relative to the chassis 2 are thus compensated. It is understood that this compensation is proportional to the amplitude of the variation of the values D and F. this amplitude being imposed by the fixed centers A and B and the gear ratio of the pig eons 34 and 36. These last wind chosen beforehand according to the length L of the swinging arm 12 and the maximum travel desired (total curve followed a priori by one end of the swinging arm in

  fixing the position of the other end).

  For this purpose, the centers A and B and the gear ratio can alternatively be adjusted during the installation on a given chassis of a suspension according to the invention, so that the rear is easily o adaptable to a large number of pre-existing chassis. For example, the bar 14 and the bar 16 can be provided with longitudinal grooves intended to allow the position of the joints 22 and 28 to be fixed along

  bars during installation of the suspension 1.

  The oscillation of the arm 12 therefore does not induce, unlike the suspensions with conventional oscillating arms detailed above in the preamble, large variations in the flywheel width of the wheel set under consideration, (nor large variations in the wheelbase wheels in the case of a motorcycle), the wheel describing, when approaching or moving the chassis away from the ground, a segment substantially perpendicular by

report to the ground.

  The suspension according to the invention therefore induces little, if any

  mechanical stress to the wheel tire, or imbalance of the vehicle.

  In FIG. 3 is shown a second embodiment of a suspension 110, which differs from the suspension 10 in FIG. 1 only by the presence on the one hand of a second swing arm 112, substantially parallel to the first swing arm 12, and on the other hand an axis 150 of articulation of the

  lower part of the damping member 18 to the wheel spindle 8.

  The arm 112 is articulated on the wheel spindle 8 about an axis 120 parallel to the axis 20, and is connected to the chassis 2 by a bar 114 substantially o parallel to the bar 14. In the same way, con that the arm 12, the arm 112 is articulated on the arm 114 around an axis 122, the arm 114 being articulated at its end on the chassis 2 around an axis 130 located directly above the axis 30 and

parallel to this axis 30.

  The suspension 110 further comprises means 140 for transmitting the movement of the bar 14 to the parallel bar 114. These means 140 are, in the embodiment of FIG. 3, in the form of a rod 142 articulated to its ends around axes 22 and 122. This "double-suspension" 110 operates in much the same way, con that the suspension 10. The double-arm >> 12, 112 forms two holding points of the wheel spindle 8 relative to the chassis 2, so as to strengthen the structure for fixing the wheel to the chassis. The damping member 18 is connected to the wheel spindle 8 by an articulation 150 which allows this member to tilt during substantially vertical movements of the chassis 2. If the damping member 18 is mounted substantially vertically , ['articulation 150 is optional for an angle

substantially zero camber.

  Another advantage of this double suspension 110 lies in the possibility of individually adjusting the dimensions of the arms 12 and 112, as well as of the bars 14, 114 and 16.11, so that it is possible to impose on the wheel 4 a variable camber angle, subject to arm travel

oscillating 12 and 112.

  o As shown schematically in Figure 4, the embodiment of the suspension 110 allows the axes of articulation, 32 and 130 to be placed on a support plate 160 not connected to the chassis 2. The bars 14 and 114 are then directly linked to the chassis by pivot axes 162 positioned in the current part of bars 14 and 114, that is to say

  respectively between axes 22 and 30, and between axes 122 and 130.

  The operation of this variant of double-arm suspension is substantially similar to that of the suspension of FIG. 3, with the difference that on the one hand the axes 22 and 122, and on the other hand the axes 30 and, and by the the support plate 160 as a whole, describe arcs so of a circle centers on the pivots 162. The compensation of the transverse movements of the wheel relative to the chassis is thus ensured in the same way as previously, the position of the pivots 162 along the

  bars 14 and 114 being adjusted accordingly during installation.

  The variant of Figure 4 allows, for an identical suspension travel, to reduce the approximation of the chassis 2 with the ground, which is advantageous for vehicles with lower chassis such as sports cars.

  Various arrangements of the embodiments described above

  wind also possible without departing from the scope of the invention. Thus, by way of example, each axle 30-pinion 34 and axle 32-pinion 36 assembly is replaced by a part of a toothed bar end, articulated on the chassis or by links also articulated on the chassis. Likewise, where the guide groove 26 - connecting pin 28 assembly is replaced by a sliding sleeve arranged around the oscillating arm and articulated at the corresponding end of the bar 16 (as shown diagrammatically on the

figure 4).

Claims (10)

  1. Suspension for land vehicle provided with a chassis and independent wheels, of the type comprising, for at least one wheel (4), at least at least one oscillating arm (12) of fixed length (L), which is articulated on a rocket (8) of the wheel and which connects the wheel to the chassis (2), and means for fixing to said swing arm on said wheel and said chassis, characterized in that said fixing means comprise, for at least one first swing arm (12), two bars (14, 16), a first end of each bar being articulated with respect to the frame (2) and a second end of where each bar is articulated on the swing arm (12), and means (34, 36) for relative drive of said first ends of the bars (14, 16) in rotation about their axis of articulation (30, 32) relative to the chassis (2), and in that on the one hand the spacing between the chassis (2) and the axis (22) of articulation of a first (14) of the two bars (14, 16) on the oscillating arm (12 ), and on the other hand the position, along the oscillating arm (12), of the axis (28) of articulation of the second (16) of said two wind bars variable fa, con to maintain substantially constant the spacing (E) between the wheel (4) and the chassis (2).   2. Suspension according to claim 1, characterized in that the axis o of articulation (28) of the second (16) of the two bars on the swing arm   (12) is guided in translation along said oscillating arm.   3. Suspension according to claim 2, characterized in that a long groove itud in ale (26) guiding the axis (28) of articulation of the second (16) of the two bars on the swing arm (12 ) is housed in s the swinging arm (12).   4. Suspension according to any one of the claims   previous, characterized in that the relative rotation drive means of said first ends of the two bars (14, 16) each comprise a gear (34, 36) whose two teeth wind in engagement with each other, each axis of said gears (34, 36) correspond to an axis of articulation (30, 32) of said first ends relative to the chassis (2).   5. Suspension according to claim 4, characterized in that the gear ratio of the teeth of the gears (34, 36) is greater than 1.   6. Suspension according to any one of the claims   s precedentes, characterized in that said first ends of the two   wind bars (14, 16) articulated directly on the chassis (2).   7. Suspension according to any one of claims 1 to 5,   characterized in that said fixing means comprise a support plate (160) on which the said first ends of the two bars (14, 16) are articulated, and in that one (14) of the two bars (14, 16) is   provided in its current part with a pivot axis (162) on the chassis (2).   8. Suspension according to any one of the claims   previous, characterized in that it comprises a second swinging arm (112), and in that the means for fixing to said second arm at the same time comprise a third bar (114) articulated on the second swinging arm (112) and substantially parallel to one of the first and second bars (14, 16) means for fixing the first swinging arm (12), and means (140) for transmitting the movement of said first or second bar (14, 16) at said third bar (114).   o 9. Suspension according to claim 8, characterized in that the transmission means (140) comprise a link (142) articulated on said first or second bar (14, 16) and on said third bar (114).   10. Suspension according to one of claims 8 or 9, characterized   s in that the means for fixing the first (12) and second (112) oscillating arms comprise a support plate (160) on which wind both articulated said first ends of the first and second bars (14, 16) and one end of said third bar (114), and in that each of the bars parallel to each other (14, 114) is provided with a pin