JP2007501728A - Flexible axle for cars - Google Patents

Abstract

The flexible axle for an automobile of the present invention has at least one transverse beam (4) and two vertical arms (2, 3) connected laterally by an anti-roll bar (5), and the anti-roll bar (5 ) Provides the flexible axle (1) with a torsional stiffness about an axis generally parallel to the anti-roll bar (5), the first end (51) of the anti-roll bar (5) It is connected to the surface (21i, 21e, 22i, 22e) of one vertical arm (2), and the second end of the anti-roll bar is connected to the surface of the second vertical arm (3). The present invention is such that the end (51) of the anti-roll bar (5) allows torsion about an axis generally parallel to the longitudinal arm (2) to which the end of the anti-roll bar (5) is attached. The elastically deformable thin plate (10) is connected to the related vertical arm (2) via the elastically deformable thin plate (10), and the elastically deformable thin plate (10) is a surface (21i, 21e, 22i, 22e). This is a portion whose range is limited by the weakened region (11).

Description

  The present invention relates to “flexible” axles for automobiles.

  Such an axle has two longitudinal arms connected laterally by at least one transverse beam and an anti-roll bar, the anti-roll bar having a flexible axle and an axis generally parallel to the anti-roll bar. The first end of the anti-roll bar is connected to the surface of the first vertical arm so as to impart torsional rigidity around the second arm, and the second end of the anti-roll bar is the second vertical arm. It is connected to the surface.

  This type of flexible axle having an H-shaped profile provides a good load holding at a very sufficient level for an occupied space smaller than the space occupied by a multi-armed axle. Because the occupied space is small, it can be easily adapted to any type of rear suspension, mainly by mechanical welding type assembly, and the application cost can be reduced. This has led to a significant expansion of flexible axle technology by automakers.

  Thus, flexible axles are increasingly used in all types of vehicles and large vehicles that previously favored multi-arm suspensions. In this type of vehicle (large sedan, one-box vehicle, and even a commercial vehicle), some parts of the anti-roll bar are absolutely in use due to the high vehicle mass and consideration for optimal function. It is used in a state close to the limit. By the way, the anti-roll bar is the most sensitive component to be developed especially in terms of durability. In addition to the quality of the anti-roll bar body, the joint area where the end of the anti-roll bar is generally connected to the arm by welding is especially designed to ensure that the connection does not break prematurely under high stress. Cost.

In order to improve the durability of this joint area, several solutions have been applied in the past to flexible axles. These solutions are made around the fact that in addition to the torsional force expected when the vehicle is tilted, the anti-roll bar also receives a large bending force that tends to deform in an S-shape in the vertical plane. Yes. This bending force has no functional value but has a significant effect on the strength of the weld bead between the anti-roll bar and the longitudinal arm. Document FR-A-2795681 discloses an anti-roll bar with an elongated cross section in order to reduce the bend due to tilting in the overall external force. However, this technology is limited by manufacturing constraints, and even if the anti-roll bar is flattened, cracks will start inside the bar, exceeding the critical value that will clearly reduce durability. It cannot actually be increased.
FR-A-2795681

  Accordingly, one object of the present invention is to reduce the portion of bending force due to the anti-roll bar tilt relative to the vehicle's lateral axis without reducing the effect of torsion around the vehicle's lateral axis. It is to provide a flexible axle that makes possible. Also, according to the purpose specific to each manufacturer, the flexible axle needs to occupy a small space, be low cost, and be easily incorporated into the automobile environment.

  In order to achieve the above object, the present invention provides a flexible axle for an automobile described at the beginning of "Background Art" of the present specification, wherein the end of the anti-roll bar is the same as the end of the anti-roll bar. It is characterized in that it is connected to the associated longitudinal arm via an elastically deformable sheet so as to allow twisting about an axis generally parallel to the longitudinal arm to be attached.

  The elastically deformable lamella is formed by intervening parts, and therefore by the part of the surface of the longitudinal arm, limited in scope by the weakened area, so as to obtain these physical properties without adding weight. Can be provided. Furthermore, due to the fact that the elastically deformable thin plate is part of the face of the vertical arm, the elastically deformable thin plate can be attached to any type of vertical arm, regardless of the overall structure of the suspension device attached to the automobile. Can be provided.

  According to a first embodiment of the present invention, the vertical arm is hollow and has at least two side walls generally parallel to the center plane of the automobile, and the weakened region is formed on the surface of the vertical arm. Created by the corresponding side wall thickness reduction region. The thickness reduction region can be provided on the inner surface of the side wall.

  According to the second embodiment of the present invention, the weakened region is constituted by an opening.

  According to one feature of the invention, the weakened region provided on the surface of the vertical arm to which the anti-roll bar is connected extends on a continuous surface of the vertical arm.

  According to a feature of the invention, the end of the anti-roll bar is connected to the side wall inside the vertical arm directed towards the other vertical arm, the weakened area Provided on the side wall.

  The transverse beam may have a U-shaped cross section, the anti-roll bar is accommodated in the transverse beam, and the weakened area is in the longitudinal arm in an area limited by the cross section of the transverse beam. Provided on the side wall.

  According to one feature of the invention, the end of the anti-roll bar is connected to the side wall outside the vertical arm directed towards the opposite side of the other vertical arm, and the weakened area Is provided on the outer side wall, and an opening having a diameter larger than the diameter of the anti-roll bar is provided on the inner side wall of the vertical arm.

  According to one characteristic of the invention, the flexible axle has the elastically deformable thin plate provided on each longitudinal arm, and generally with respect to the vertical vertical center plane of the vehicle. It has a symmetric configuration.

Other features and advantages of the present invention will become apparent upon reading the following detailed description, with reference to the accompanying drawings for understanding. In the attached drawing:
FIG. 1 is a schematic diagram of a flexible axle according to the invention;
-Figure 2 is a schematic diagram of the principle of the present invention;
-Fig. 3 is a perspective view of a flexible axle according to a first embodiment of the invention;
FIG. 3A is a cross-sectional view of the flexible axle shown in FIG. 3 cut along a vertical plane through the axis of the anti-roll bar;
-Fig. 4 is a perspective view of a flexible axle according to a second embodiment of the invention;
FIG. 4A is a cross-sectional view of the flexible axle shown in FIG. 4 taken along a vertical plane through the axis of the anti-roll bar;
-Fig. 4B is a cross-sectional view similar to Fig. 4a of a flexible axle according to one variant of implementation of the invention;
FIG. 5 is a sectional view of a flexible axle according to a first variant of the second embodiment, cut along a vertical plane passing through the axis of the anti-roll bar;
-Fig. 6 is a perspective view of a flexible axle according to a second variant of the second embodiment;
-Fig. 7 is a perspective view of a flexible axle according to a third variant of the second embodiment;
-Figures 8A, 8B, 8C and 8D are schematic illustrations of various variants of the weakened area concept according to the invention.

  In the following description, the vertical, vertical, and horizontal directions traditionally used in automobiles and indicated by the trihedrons L, V, and T of the various drawings are employed in a non-limiting manner.

  As shown in FIG. 1, the flexible rear axle 1 is composed of two vertical arms 2 and 3 connected by a cross beam 4. Advantageously, the longitudinal arm is in the form of a hollow tube having at least two side walls 21, 22 generally parallel to the central vertical plane of the motor vehicle. However, the present invention is also applicable to other shaped arms. A parallel anti-roll bar 5 extends from one vertical arm 2 toward the other vertical arm in parallel with the horizontal beam 4. Since such a flexible axle 1 is symmetric with respect to the central vertical plane of the vehicle, ie the plane including the longitudinal central axis XX ′ and the vertical axis, only the right half of the flexible arm will be described below. 2-8 are illustrated. This description and illustration also applies to the left half of the flexible axle of the present invention due to symmetry.

  The front end of the vertical arm 2 is rotatably connected to the vehicle body via a bearing 6, and the rear end of the vertical arm 2 is connected to a wheel support 7. The end portion 51 of the anti-roll bar 5 is welded to the inner side wall 21 of the vertical arm 2 at a position where the distance from the wheel support 7 and the bearing 6 is substantially equal. Depending on the structure of the automobile suspension and the performance desired for the anti-roll bar 5, the outer side wall 22 of the vertical arm 2, that is to the opposite side of the other vertical arm 3, as illustrated in FIG. It is also possible to envisage an anti-roll bar whose length is welded at the end to the side wall.

  According to the present invention, the weakened region 11 is provided on the inner side wall 21 of the vertical arm 2 to which the anti-roll bar 5 is welded in order to obtain the elastically deformable thin plate 10 for attaching the anti-roll bar 5. . The weakened region 11 is provided by reducing the thickness of the inner side wall 21 in the generally longitudinal direction so as to give this region some flexibility with respect to torsion about the generally longitudinal axis. FIG. 2 shows a principle diagram of the behavior of the elastically deformable thin plate 10 when the automobile is tilted.

  According to a first embodiment of the type shown in FIG. 3, the weakened region 11 is an opening 12 localized in the inner side wall 21 to which the anti-roll bar 5 is welded. A second embodiment of this weakened region 11 of the type shown in FIG. 4 is obtained by the reduced thickness region 13 of the inner side wall 21. As an example, FIG. 4A shows such a thickness reduction region 13 provided on the outer surface 21 e of the inner side wall 21. Such an embodiment with a reduced thickness region 13 makes it possible to avoid providing the opening 12 in the longitudinal arm 2 and to avoid the expense of closing the opening 12 for waterproofing, ie to prevent corrosion. . In an embodiment in which the weakened region 11 is obtained by the opening 12, after the end 51 of the anti-roll bar 5 is welded to the longitudinal arm 2, the opening is formed by, for example, at least one of a deformable material and a plastic cap not shown. It should be noted that it is desirable to attach a cover to 12. When the vertical arm 2 is manufactured, the thickness reducing region 13 can be provided on the inner surface 21 i of the inner side wall 21. The variant of this embodiment shown in FIG. 4B further presents the advantage of allowing a thicker weld bead around the anti-roll bar 5. In an embodiment not shown, in order to obtain a thicker weld bead, the thickness reduction region 13 is provided on the outer surface 21e of the inner side wall 21 and the anti-roll bar 5 is welded to the inner surface 21i. In this case, the vertical arm 2 is made from two parts which are later integrated by welding to allow welding to the inner surface 21i of the anti-roll bar 5.

  When the anti-roll bar 5 is welded to the outer side wall 22 of the vertical arm 2, and thus when the anti-roll bar 5 “penetrates” the vertical arm 2 in the lateral direction, the weakened region 11 is placed on the outer side wall 22. Provided. However, the inner side wall 21 needs to allow torsional movement about the generally longitudinal axis of the anti-roll bar 5. This torsional movement is made possible by the elastically deformable sheet 10 formed on the outer side wall 22. Therefore, as shown in FIG. 5, the inner side wall 21 needs to have an opening whose diameter is sufficient to allow movement of the anti-roll bar 5, ie at least exceeding the diameter of the anti-roll bar 5.

  Each end 51 of the anti-roll bar 5 is connected to the vertical arm 2 in the same manner as the horizontal beam 4. The anti-roll bar 5 may be housed inside the cross beam 4 depending on the arrangement of the rear axle / wheel portion of the automobile and the shape of the cross beam 4 (FIG. 6 shows a cross beam having a U-shaped cross section. The structure of such a suspension system is shown.) In this case, the elastically deformable thin plate 10 is formed on the outer side wall 21 only when the anti-roll bar 5 is welded to the inner side wall 21 and when the anti-roll bar 5 is welded to the outer side wall 22. It should be provided only on the side wall 22. When the portion of the vertical arm 2 to which the end portion 51 of the anti-roll bar 5 is welded is not located in the front cross beam 4, the elastically deformable thin plate 10 is a weak body provided on a plurality of continuous surfaces. It can be obtained by the conversion region 11. In this case, as shown in FIG. 7, the main direction of the weakened region 11 needs to remain substantially longitudinal so as to allow twisting about the generally longitudinal axis of the anti-roll bar 5.

  The functional area contained between the weakened areas 11 combines good flexibility with respect to torsion around the longitudinal axis of the vehicle and great rigidity with respect to torsion around the lateral axis of the vehicle. Accordingly, the functional areas included between the weakened areas 11 significantly limit the harmful effects of bending without affecting the torsion of the anti-roll bar 5 being transmitted substantially entirely, as described above. It directly meets the various objectives of the present invention. Various embodiments of the present invention allow mass and cost benefits to be obtained without imposing general structural constraints on the flexible axle concept.

  According to the present invention, the material region included between the weakened regions 11 is a high stress region because the amount of material that transmits the torsional stress of the anti-roll bar 5 to the longitudinal arm 2 is reduced. 8A-8C show in a non-limiting manner the shape of the weakened region 11 that has been optimized taking into account the main parameters. These main parameters include, for example, the radius of curvature of the end of the weakened region 11, the length of the weakened region 11, and the shape of the weakened region 11 (whether open or closed at the end). Furthermore, the distance between the weakened region 11 and the region to which the anti-roll bar 5 is fixed is such that a weld bead suitable for withstanding the stress transmitted from the anti-roll bar 5 to the vertical arm 2 is provided at the end of the anti-roll bar 5. It is large enough to be attached to the vertical arm 2 around the part. In order to allow easier welding, the side end 51 of the anti-roll bar 5 may be penetrated into the thickness of the side wall 21 of the vertical arm 2.

  As shown in FIG. 8D, the asymmetry between the shape of the weakened region 11 in front of the anti-roll bar 5 and the shape of the weakened region 11 in front of the anti-roll bar 5, for example, due to structural constraints Can be compensated, for example, by appropriately selecting different lengths and different gaps in the front and back of the weakened region 11 (relative to the anti-roll bar 5).

Claims (10)

  Having at least one transverse beam (4) and two longitudinal arms (2, 3) connected laterally by an anti-roll bar (5), said anti-roll bar (5) being attached to a flexible axle (1) The first end (51) of the anti-roll bar (5) has a first longitudinal arm (2) so as to impart torsional rigidity about an axis generally parallel to the anti-roll bar (5). The second end of the anti-roll bar (5) is connected to the surface of the second vertical arm (3) and is connected to the surface (21i, 21e, 22i, 22e). In the axle, the end (51) of the anti-roll bar (5) allows twisting about an axis generally parallel to the longitudinal arm (2) to which the end of the anti-roll bar (5) is attached. Via the elastically deformable thin plate (10) The vertical being coupled to the arm (2), characterized in, flexible axle for a motor vehicle that.   The elastically deformable thin plate (10) is a portion whose range is limited by the weakened region (11) of the surface (21i, 21e, 22i, 22e) of the vertical arm (2). The flexible axle for an automobile according to claim 1.   The vertical arm (2) is hollow and has at least two side walls (21, 22) substantially parallel to the central plane of the automobile, and the weakened region (11) is formed by the surface (21i, Flexible axle for a motor vehicle according to claim 2, characterized in that it is created by a thickness reduction region (13) of the corresponding side wall (21, 22) of 21e, 22i, 22e).   The flexible axle for an automobile according to claim 3, characterized in that the thickness reduction region (13) is provided on the inner surface (21i, 22i) of the side wall (21, 22).   A flexible axle for an automobile according to claim 2, characterized in that the weakened area (11) is constituted by an opening (12).   The weakened region (11) provided on the surface of the vertical arm (2) to which the anti-roll bar (5) is connected extends on a continuous surface of the vertical arm (2), A flexible axle for a motor vehicle according to any one of claims 2 to 5.   The end (51) of the anti-roll bar (5) is connected to the side wall (21) inside the vertical arm (2) directed toward the other vertical arm (3), and A flexible axle for an automobile according to claim 2, characterized in that the weakened area (11) is provided on the inner side wall (21).   The cross beam (4) has a U-shaped cross section, the anti-roll bar (5) is accommodated in the cross beam (4), and the weakened region (11) is a cross section of the cross beam (4). Flexible axle for an automobile according to any one of claims 2 to 7, characterized in that it is provided on the side wall (21) of the longitudinal arm (2) in a region limited by .   The end (51) of the anti-roll bar (5) is connected to the side wall (22) outside the vertical arm (2) facing away from the other vertical arm (3). The weakened region (11) is provided on the outer side wall (22), and an opening having a diameter larger than the diameter of the anti-roll bar (5) is formed on the inner side wall of the vertical arm (2) ( 21. A flexible axle for an automobile according to claim 2, characterized in that it is provided in 21).   Each of the vertical arms (2, 3) has the elastically deformable thin plate (10) provided on each of the vertical arms (2, 3), and has a generally symmetric configuration with respect to a vertical vertical central plane of the vehicle A flexible axle for a motor vehicle according to any one of the preceding claims, characterized in that it is characterized in that

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