Title of Invention

"A FLEXIBLE AXLE FOR AUTOMOBILE VEHICLE"

Abstract The invention relates to a flexible axle which is intended for a motor vehicle. The inventive axle comprises a cross-member (1) which connects two longitudinal arms (2), each of said arms being solidly connected to at least one cup part (3). Moreover, the axle is equipped with means for positioning and/or supporting (33) at least one suspension spring. The invention is characterised in that the aforementioned cross-member (1) is connected to each longitudinal arm (1) by means of at least one cup (3) comprising stiffening means (31) which are intended to increase the transverse stiffness of the axle.
Full Text FLEXIBLE AXLE HAVING A TRANSVERSE STIFFNESS WHICH IS
INCREASED BY AT LEAST ONE SPRING DISH-FORMING PART,
SPRING DISH AND CORRESPONDING VEHICLE
The field of the invention is that of automobile vehicles. More specifically, the invention relates to flexible axles for automobile vehicles.
It is noted that the term flexible axle generally refers to an axle designed so as to form an element that is torsionally flexible between two wheels.
Conventionally, a flexible axle includes -wo longitudinal arms each bearing a wheel mounting support and connected by a transverse linking element called a cross piece or a profile.
The longitudinal arms are generally associated with different functional components, such as, in particular:
bushings for coupling the axle to the vehicle chassis, enabling the longitudinal arms to be pivotably mounted on the chassis; means supporting an end of the suspension springs, which support means are referred to as spring dishes;
means for cooperation with shock absorbers.
In the design of an axle, two capacities, among other things, are considered in order to assess the quality of the spring: bending and torsion.
The concept, now widely known, of flexible axles involves balancing a high bending stiffness with relative torsional flexibility. In general, it is the shape of the cross section of the cross piece, via its bending and torsional inertia, that provides the desired compromise between bending stiffness and (relative) torsional flexibility.
The cross sections selected in the production of steel (or other isotropic material) cross braces often have "V", "U" or "L" shapes, because these shapes have a good ratio between bending inertia and torsional inertia.
As regards the assembly of the suspension spring dishes, a number of assembly types have been proposed by the prior art.
In the following description, the term "spring dish" refers to a part having a surface intended to support the base of a suspension spring, which surface includes means for positioning and/or holding the spring in position. Such means are usually constituted by a centring stud.
In many cases, the dishes are mounted on the axle so as to be supported solely by the longitudinal arms, by being welded thereto in the region of the wheel mounting support.
The dishes are thus designed so that the assembly resists the load transmitted by the suspension spring,
with the dish being to some degree suspended from the axle arm and coupled thereto by two types of lateral compression beams. These springs must therefore be particularly strong.
In addition, the transverse rigidity of these axles is relatively limited, except when specific stiffening means are provided, which then necessitate additional assembly and production operations.
This of course increases the cost of the axle.
In other cases, the dishes have been mounted in each corner formed by the cross piece and the longitudinal arms (on the side of the arms bearing the wheel supports).
According to this technique, each dish has a structure provided exclusively to support a suspension spring. In other words, these dishes are in no way designed to perform a stiffening function on the axle.
In addition, when the dishes are thus positioned on the axle, it becomes impossible, or practically impossible, to add stiffening means at the level of the corner between the cross piece and each of the longitudinal arms,
Consequently, the axle obtained according to this technique has a relatively limited performance, in particular with regard to its transverse stiffness (bending strength).
Of course, it would be possible to improve the rigidity cf such an axle, in particular by using a material that is intrinsically stronger, or by increasing the thickness of the cross section of the cross piece.
However, this would lead to an additional expense, which is obviously undesirable.
Moreover, this increase in bending stiffness would be obtained to the detriment of the torsional characteristics of the axle.
The objective of the invention is in particular to overcome the disadvantages of the prior art.
More specifically, the invention aims to propose a flexible axle in which the design of the dish makes it possible to consider simplifying the assembly of the axle, without this simplification causing a limitation in performance (torsion, bending, mechanical strength, etc.) of the axle.
In this sense, the invention aims in particular to improve the transverse stiffness of the axle, while retaining, or almost retaining, its torsional characteristics.
The invention also aims to provide such an axle in which the design and the assembly of the dish contribute to the good performance of the welds between the cross piece and the longitudinal arms.
The invention also aims to provide such an axle that makes it possible to envisage reducing its production cost.
Another aim of the invention is to provide such an axle with a simple design and that is easy to implement.
These objectives, as well as others which will be described below, are achieved by the invention, which relates to a flexible axle for an automobile vehicle including a cross piece connecting two longitudinal arms each secured to at least one part, referred to as
a dish, having means for positioning and/or holding at least one suspension spring, characterised in that said cross piece is connected to each longitudinal arm by at least one dish including stiffening means intended to increase the transverse stiffness of said axle.
Owing to the design and assembly of the dish according to the invention, the latter performs a dual function:
a first, conventional function consisting of supporting the vertical load corresponding to the mass of the vehicle and transmitted by the suspension spring;
a second function, consisting of rigidifying the axle, using means specifically provided for this purpose.
This second function is explained in greater detail in reference to figures 1 and 2.
Figure 1 diagrammatically shows a flexible axle according to the prior art, including a cross piece 1 connecting two longitudinal arms 2. Thus constituted, the cross piece of the axle is capable of bending over a length LI, and confers, for a predetermined cross section and material, a transverse stiffness Kl on the axle.
In figure 2, the axle includes a cross piece 1 in particular connected to each longitudinal arm 2 by a dish 3 including stiffening means according to the invention.
Thus, the cross piece of the axle is now capable of bending over a length L2 shorter than length LI of figure 1.
Consequently, with a cross section and a material identical to those of figure 1, a transverse stiffness K2 of the axle, greater than the stiffness Kl of figure 1 is obtained, and the bending is limited to the length L2 of the cross piece.
In addition, the dish designed and mounted according to the invention makes it possible to smooth the variation in torsional stiffness of the cross piece, between section SI (generally open in the case of flexible axles) and section S2 of the cross piece embedded in the arm. This contributes to the strength of the welds (in the form of seams) made directly where the cross piece is embedded in the arms.
Moreover, the axle according to the invention is produced with a fewer parts by comparison with the prior art having a transverse thickness on the same order. Indeed, the dishes solidify the connection between the cross piece and the longitudinal arms, and it is therefore unnecessary to provide stiffening means in addition to the dishes.
The axle production plans according to the invention are therefore relatively simple, and the corresponding assembly times are reduced.
Advantages can therefore be envisaged with regard to the cost of producing an axle according to the invention.
Said stiffening means preferably include at least one essentially planar portion connecting said cross piece and one of said longitudinal arms.
Simple and effective means for providing the stiffening function are thus obtained, which means are
capable of being easily connected to, or even included
in the dish.
Advantageously, said portion(s) are essentially in the plane defined by said cross piece and said arms or in a plane parallel thereto.
In this way, the stiffening portion is optimally positioned so as to increase the transverse stiffness of the axle. Indeed, the plane of the stiffening portion is then a plane substantially parallel to the one in which the stresses act on the wheel supports (along the axis of the wheels).
According to a preferred embodiment, each of said dishes has a support surface intended to support a suspension spring, which support surface is distinct from said stiffening means and connected thereto by a junction edge.
In this case, said support surface and said edge advantageously form a recess intended to receive an end of said suspension spring.
This contributes to the proper positioning and maintenance of the suspension spring on the axle.
According to a preferred solution, said stiffening means consist of a planar surface defined in particular by a portion of said cross piece, a portion of one of the longitudinal arms and said junction edge.
In this way, to implement the stiffening means, all (or almost all) of the space available in each corner of the axle, between the cross piece, the corresponding longitudinal arm and the support surface of the suspension spring is used.
Bending stresses capable of acting on the axle are thus dissipated over the entire planar surface as defined above.
Advantageously, said dish-forming part has, at least on its side placed facing said cross piece, a welding area in the plane of said stiffening portion, having a continuous weld seam securing said part to said cross piece.
The dish thus has a simple design and is inexpensive to produce. Moreover, the weld between the dish and the cross piece is created in a single operation.
According to an advantageous solution, said dish-forming part has, on its side placed facing a longitudinal arm, at least one tab of which the free end extends substantially parallel to said longitudinal arm with a weld seam securing said part to said arm, which dish also has, on its side opposite a longitudinal arm, a concave edge in contact with a portion of the periphery of said arm, which concave edge has a weld seam securing said part to said cross piece.
The connections between the dish and the longitudinal arm and the cross piece are thus obtained in an effective and reliable manner, even if the axle is subjected to significant stresses during use of the vehicle.
Said dish-forming part is preferably made of a steel plate.
Such a material has the advantages of being inexpensive and relatively easy to work with.
In this case, the dish is preferably formed by
stamping.
Other embodiments can of course be envisioned, in particular by making the dish with other materials and/or by moulding.
According to another characteristic, said tab is welded to the highest portion of the section of each longitudinal arm, or in the region thereof.
In this way, the incorporated stiffening means are brought together with the dish of the plane where the stresses act along the axis of the wheels and are transmitted by means of the wheel supports.
It is noted that an ideal configuration (but difficult to achieve) would consist of providing the stiffening means directly at the level of the wheel axis.
Said welding area is preferably welded on the highest portion of the section of said cross piece or in the region thereof.
The weld thus produced between the dishes and the cross piece has a satisfactory fatigue strength, which is at least better than a connection in which each dish is welded, for example, at mid-height on the cross piece.
Said planar portion preferably extends along said longitudinal arm until the wheel support or the region thereof.
Thus, positioned with respect to the wheel axis, the stiffening means have a good capacity for absorbing and dissipating the stresses transmitted by the wheel supports.
According to another advantageous characteristic, said means for positioning and/or holding each of said dishes include a centring stud formed in the support surface intended to support said suspension spring, which centring stud is produced by stamping.
The invention also relates to a dish having means for positioning and/or holding at least one suspension spring, intended to equip a flexible axle of an automobile vehicle, characterised in that it is provided in order to connect the cross piece to a longitudinal arm of the axle, which dish includes stiffening means intended to increase the transverse stiffness of said axle.
The invention also relates to an automobile vehicle equipped with at least one axle including a cross piece connecting two longitudinal arms each secured to at least one part, referred to as a dish, having means for positioning and/or holding at least one suspension spring, characterised in that said cross piece is connected to each longitudinal arm by at least one dish including stiffening means intended to increase the transverse stiffness of said axle.
Other characteristics and advantages of the invention will become more clear from the following description of a preferred embodiment of the invention, provided by way of an illustrative and non-limicing example, and the appended drawings wherein:
figure 1 is a diagrammatic representation of a flexible axle according to the prior arc; figure 2 is a diagrammatic representation of a flexible axle according to the invention;
figure 3 is a perspective view of an axle
according to the invention;
figure 4 is a perspective view of a dish
intended to equip an axle according to the
invention.
As already mentioned, the principle of the invention consists of connecting the cross piece with each of the longitudinal arms using a dish provided to increase the transverse stiffness of the axle.
In reference to figure 3, such a flexible axle includes a cross piece I connecting two longitudinal arms 2 each bearing:
a wheel support plate 21;
a bushing 22, which connects the axle to the
vehicle chassis;
means for cooperation 23 with a shock
absorber.
According to this embodiment of the invention, the dishes 3 are mounted in the corners formed by the axle 1 and the longitudinal arms 2, each of the dishes having a planar surface 31 forming stiffening ir.eans intended to increase the transverse stiffness of the axle.
This dish is shown, isolated from the axle, in figure 4 .
As shown in figure 4, a dish according to the invention is made of a steel plate, by stamping, and has a surface 32 intended to support the base of a suspension spring.
By way of indication, the material of the plate is a grade of steel such as HE360D and the plate has a thickness of 3 mm.
During the stamping operation, a centring stud 33 is formed, which enables the suspension spring to be positioned and held in place.
Orifices 34 are also provided in the support surface 32 of the dish 3, the function of which orifices 34 is to provide, in a manner known per se, gripping means for an automatic system on the assembly line.
As clearly shown, the support surface 32 is bordered by an edge 35 which connects the support surface 32 to the planar surface 31 forming stiffening means.
Thus, the support surface 32 and the edge 35 form, with respect to the surface 31, a hollow recess intended to receive one or more end coils of the suspension spring.
More specifically, the dimensions of the edge are such that the hollow recess of the dish 3 is obtained by a deep-drawn part, that is, a drawing operation in which the thickness of the material with respect to its drawing approaches the tearing limit of the material.
In addition, the dish 3 has, on its side intended to be placed opposite the cross piece 1, a welding area 36 (at the boundary of the surface 31) intended to have a continuous weld seam ensuring the secure connection between the dish and the cross piece.
On its other side (intended to be placed opposite a longitudinal arm), the dish 3 has:
a tab 37 arranged so as to extend parallel to the corresponding longitudinal arm, and intended to have a weld seam securely attaching the dish to the longitudinal arm; a concave edge 38 arranged so as to come into contact with a portion of the periphery of the corresponding longitudinal arm and intended to have a weld seam securely attaching the dish to the longitudinal arm. As shown in figure 1, the surface 31 forming
stiffening means is arranged so as to extend in the
space defined by the cross piece 1, a longitudinal arm
2 and the edge 35 of the dish 3.
As shown, the surface 31 of each dish extends
along the corresponding longitudinal arm 2 until the
wheel support plate 21.
It is noted that the secure connection of the dish
in particular enables:
the welding area 36 of the dish to be welded onto the cross piece 1, so that the welding area tends to cover the cross piece; the tab 37 of the dish to be welded onto the longitudinal arm 2, so that the tab tends zo cover the cross piece.







We Claim:
1. Flexible axle for automobile vehicle comprising a cross piece (1) connecting two
longitudinal arms (2) each fixed to at least one part, called a dish (3) with means (33) of
positioning and / or holding at least one suspension spring,
characterised in that the said cross piece (1) is connected by at least one dish (3) to each longitudinal arm (1) including stiffening means (31) that will increase the transverse stiffness of the said axle,
the dishes being mounted in the corners formed by the cross piece and
the longitudinal arms, each of the said dishes having a support surface (32) that will support a suspension spring, the said support surface (32)being separate from the said stiffening means (31) and
connected to the said stiffening means by a junction edge (35), the said stiffening means (31) being composed of a plane surface delimited particularly by a portion of the said cross piece (1), by a portion of one of the longitudinal arms (2) and by the said junction edge (35).
2. Axle as claimed in claim 1, wherein said stiffening means (31) comprise at least one essentially plane portion directly connecting the said cross piece (1) and one of the said longitudinal arms (2).
3. Axle as claimed in claim 2, wherein said portion(s) is (are) essentially inscribed within the plane defined by the said cross piece (l)and the said arms (2) or in a plane parallel to it.
4. Axle as claimed in claim 1, wherein said support surface (32) and the said edge (35) form a recess that will hold one end of the said suspension spring.
5. Axle as claimed in claims 2 to 4,characterised in that the said part forming the dish (3)has at least on its side placed facing the said cross piece (1), a welding area (36) in the plane of the said stiffening portion (31) carrying a continuous weld 10 fixing the said part to the said cross piece.
6. Axle as claimed in claims 2 to 5, wherein said part forming the dish (3) has on its side placed facing a longitudinal arm (2),at least one tab (37) for which the free edge extends approximately parallel to the said longitudinal arm (2)and carrying a weld fixing the said part to the said arm (2), the said dish (3) also being provided with a concave edge (38) facing a longitudinal arm (2) and
matching a portion of the periphery of the said arm (2),the said concave edge (38) supporting a weld fixing the said part (3) to the said arm (2).
7. Axle as claimed in claims 1 to 6, wherein said part forming the dish (3) is made of steel
plate.

8. Axle as claimed in claim 7, wherein said part forming a dish (3) is made by stamping.
9. Axle as claimed in claims 5 to 8, wherein said tab (37) is welded to the highest part of the section of each longitudinal arm (2) or close to it.

10. Axle as claimed in claims 1 to 9, wherein said welding area (36) is welded onto the highest part of the section of the said cross piece (1) or close to it.
11. Axle as claimed in claims 2 to 10, wherein said plane portion extends along the said longitudinal arm (2) as far as the wheel support (21) or close to it.
12. Axle as claimed in claims 1 to 11, wherein said positioning and / or holding means (33) of each of the said dishes comprise
a centering stud made in the support surface (32) that will support the said suspension spring, the said centering stud being made by stamping.
13. Dish with means (33) for positioning and / or holding at least one suspension spring designed to be fitted onto a flexible automobile vehicle axle according to any one of claims 1 to 12, characterized in that it is designed to connect the cross piece (1) to a longitudinal arm (2) of the axle, the said dish (3) including stiffening means (31)designed to increase the transverse stiffness of the said axle, the dishes being mounted in the corners formed by the cross piece and the longitudinal arms, each of the said dishes having a support surface (32) that will support a suspension spring, the said support surface (32) being separate from the said stiffening means (31) and connected to the said stiffening means by a junction edge (35), the said stiffening means (31) being composed of a plane surface delimited particularly by a portion of the said cross piece (1), by a portion of one of the longitudinal arms (2) and by the said junction edge (35).
14. Automobile vehicle equipped with at least one axle as claimed in claims l to 12.

Documents:

2215-delnp-2006-Abstract (16-11-2009).pdf

2215-delnp-2006-abstract.pdf

2215-delnp-2006-Claims (16-11-2009).pdf

2215-delnp-2006-claims.pdf

2215-delnp-2006-Correspondence-Others (16-11-2009).pdf

2215-DELNP-2006-Correspondence-Others (26-11-2009).pdf

2215-delnp-2006-correspondence-others-1.pdf

2215-delnp-2006-correspondence-others.pdf

2215-delnp-2006-Description (Complete) (16-11-2009).pdf

2215-delnp-2006-description (complete).pdf

2215-delnp-2006-Drawings (16-11-2009).pdf

2215-delnp-2006-drawings.pdf

2215-delnp-2006-Form-1 (16-11-2009).pdf

2215-delnp-2006-form-1.pdf

2215-delnp-2006-form-18.pdf

2215-delnp-2006-Form-2 (16-11-2009).pdf

2215-delnp-2006-form-2.pdf

2215-DELNP-2006-Form-3-(26-11-2009).pdf

2215-delnp-2006-form-3.pdf

2215-delnp-2006-form-5.pdf

2215-delnp-2006-gpa.pdf

2215-delnp-2006-pct-306.pdf

2215-delnp-2006-pct-409.pdf

2215-DELNP-2006-Petition Others (26-11-2009).pdf

2215-DELNP-2006-Petition Others-1 (26-11-2009).pdf

2215-DELNP-2006-Petition Others-2 (26-11-2009).pdf


Patent Number 240221
Indian Patent Application Number 2215/DELNP/2006
PG Journal Number 19/2010
Publication Date 07-May-2010
Grant Date 29-Apr-2010
Date of Filing 24-Apr-2006
Name of Patentee AUTO CHASSIS INTERNATIONAL SNC LEM CTC 0.06
Applicant Address 15, Avenue Pierre Piffault, F-75086 Le Mans Cedex 9 (FRANCE).
Inventors:
# Inventor's Name Inventor's Address
1 FERET Olivier 10, route de la Ferté Bernard, F-72400 Cherreau, FRANCE.
2 VENEAU, Jean 4, Le Champ du Verger, F-72370 Ardenay sur Merize (FRANCE).
3 THIRIEL Jean-Marc 26, rue de Pologne, F-78700 Conflans Ste Honorine (FRANCE).
PCT International Classification Number B60B 33/04
PCT International Application Number PCT/FR2004/002784
PCT International Filing date 2004-10-28
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 0312645 2003-10-29 France