Method for producing torsionally flexible axle structures

Abstract

The present invention relates to a method for producing axle structures comprising the steps of: providing pairs of first arms having a first cross-section and pairs of second arms (32) having a second cross-section larger than the first cross-section; providing a plurality of crossmembers (28) in order to be able to respectively connect the pairs of arms (32) together. The crossmembers (28) are all identical and the following are also provided: pairs of first sleeves each having a connecting end and, opposite, a first receiving seat of a first width in order to be able to receive arms of the pairs of first arms; and, pairs of second sleeves (34) each having a connecting end and, opposite, a second receiving seat of a second width larger than the first width, in order to be able to receive arms of the pairs of second arms (32).

Description

[0001] Title of the invention: Method for manufacturing twistable axle structures

[0002] [The present invention relates to a method of manufacturing twistable axle structures for a motor vehicle.

[0003] Known rear axles of motor vehicles comprise a pair of control arms for connecting the rear wheel carriers to the body. Both control arms are pivotally mounted on the body and extend toward the rear of the vehicle. Furthermore, these two opposing control arms are connected to each other by a cross member.

[0004] This type of axle is commonly used at the rear of passenger vehicles. The axle crossmembers are then subjected to both high rolling stresses and large amplitude deformations to control oscillations on slopes as well as camber and steering movements induced by this slope.

[0005] Sleepers are usually tubular and their profile generally varies symmetrically, from the center to the two ends. They are generally made from a stamped and welded sheet metal blank or from a stamped tube.

[0006] Furthermore, their size and geometry are dictated by the type of motor vehicles for which they are intended. Indeed, they depend in particular on the mass possibly supported by the rear axle of the vehicle, the track or even the length of the suspension arms.

[0007] Therefore, sleepers of different types are developed to meet the requirements of different types of vehicles.

[0008] On the other hand, the design and production of sleepers are relatively complex and require heavy investment, particularly to produce the tools needed for this purpose. As a result, the cost of motor vehicles is increased accordingly.

[0009] Also, a problem that arises and that the present invention aims to solve is to provide a method of manufacturing twistable axle structures that does not increase the cost of the vehicles.

[0010] For this purpose, a method for manufacturing twistable axle structures of a motor vehicle is proposed, comprising the following steps: providing pairs of first arms of a first section adapted to connect the two wheels and the body of a first type of vehicle and pairs of second arms of a second section greater than said first section, adapted to connect the two wheels and the body of a second type of vehicle; providing a plurality of cross members to be able to connect together respectively the arms of said pairs of arms.The crosspieces of said plurality of crosspieces are all identical and there are further provided: pairs of first T-shaped coupling sleeves each having a connecting end with said crosspieces and opposite a first receiving seat of a first width to be able to receive arms of said pairs of first arms; and, pairs of second T-shaped coupling sleeves each having a connecting end with said crosspieces and opposite a second receiving seat of a second width greater than said first width, to be able to receive arms of said pairs of second arms.

[0011] Thus, a feature of the invention lies in the implementation of a single type of cross member in the torsion axle structures of different types of motor vehicles, where the section of the pairs of suspension arms varies. To do this, different sleeves are implemented, the connecting end of which is identical for all so as to be able to receive the end of the cross members, and the opposite end of which, i.e. the receiving seat, is more or less wide to be able to adapt to the section of the arms.

[0012] In other words, for all twisting axle structures, the same cross member is used and connected to suspension arms of different sections by using different types of coupling sleeves. These, in their various versions, are easy to manufacture, as will be explained below, and require simpler tools than those needed to make the cross members. They are therefore inexpensive. And a single type of cross member, whose design is complex and therefore expensive, is used for different types of vehicles.

[0013] In addition, the use of sleeves between the cross members and the arms allows for a more robust connection without compromising the anti-roll stiffness of the assembly or its mass.

[0014] According to a particularly advantageous embodiment of the invention, said connecting end has a free edge closed on itself and each of said crosspieces is fitted inside said free edge. Thus, the end of the crosspieces is engaged inside the free edge of the sleeves, which makes it possible to improve the mechanical strength of the connection.

[0015] In addition, said free edge and the crosspiece are connected to each other by a first weld bead. This first weld bead preferably extends continuously all around the end of the crosspiece, and straddling the edge and the crosspiece.

[0016] Also, advantageously, each of said sleeves has, opposite the fitting end, two facing notches to form the seat. These two notches are preferably made in a U shape and they are symmetrical to each other with respect to a median plane. In this way, they perfectly form the seat in which the arm rests.

[0017] Furthermore, said two notches define a notched edge and said notched edge is connected to said arms by a second weld bead. In other words, the notched edge is continuous and it closes on itself. Therefore, a second weld bead, preferably continuous, is applied in a loop at the joint between the notched edge and the arm. This results in a perfect connection of the sleeve and the arm.

[0018] According to a particularly advantageous embodiment of the invention, each of said sleeves is formed from two arched pieces welded together. The sleeves are thus produced from two arched pieces cut and stamped from a metal plate. They are thus produced at an advantageous cost. They are then welded together as will be explained below.

[0019] Preferably, each of said two arched pieces comprises a portion of cylindrical symmetry having two facing wings defining a straight edge, and a middle portion extending at a point opposite said straight edge. Thus, the two arched pieces are connected by their two wings, so that their straight edges extend in the same plane. The straight edges thus define the fitting perimeter of the end of the crosspieces. Conversely, the middle portions of the two arched pieces together define the seat capable of receiving the arm.

[0020] According to a preferred embodiment, the two arch pieces are welded together before connecting the crosspiece and arms.

[0021] Furthermore, and according to a particularly advantageous embodiment, one of said two arched parts of each of said second T-shaped coupling sleeves has a median portion that is offset relative to said cylindrical portion. In this way, the median portion that is offset is substantially spaced apart from the median portion of the other of the two arched parts. And consequently, the two median portions spaced apart from each other make it possible to obtain a wider seat to accommodate the arms of a larger section. Furthermore, the other of said two arched parts of each of said second T-shaped coupling sleeves advantageously has a median portion in the form of a notched point. This notch is made along a plane substantially parallel to the straight edge so as to make the connection with an arm of a larger section easier.

[0022] According to a particularly advantageous variant of the method according to the invention, at least pairs of third arms of a third section greater than said second section are provided, adapted to connect the two wheels and the body of at least a third type of vehicle; and, at least pairs of third T-shaped coupling sleeves are provided, each having a connecting end with said crossmembers and opposite a third receiving seat of a third width to be able to receive arms of said pairs of third arms. In this way, a single type of crossmember is used, identical in their dimensions and in their section, for a plurality of types of motor vehicles. Thus, the costs of designing and producing a single crossmember are amortized over a greater number of vehicles. Consequently, the manufacturing costs of the torsion axle structure according to the invention are reduced.

[0023] Other features and advantages of the invention will emerge from reading the description given below of particular embodiments of the invention, given for informational but non-limiting purposes, with reference to the appended drawings in which:

[0024] [Fig. 1] is a schematic perspective view of a conventional motor vehicle twist axle structure;

[0025] [Fig. 2] is a partial schematic top view of an axle structure according to the invention according to one embodiment;

[0026] [Fig. 3] is a partial schematic top view of an axle structure according to the invention according to another embodiment;

[0027] [Fig. 4] is a schematic sectional view along plane IV - IV referenced in [Fig. 2]; [Fig. 5] is a schematic sectional view along plane V - V referenced in [Fig. 2];

[0028] [Fig. 6A] is a schematic side perspective view of an element of the object shown in [Fig. 2]

[0029] [Fig. 6B] is a schematic perspective view of an element of the object of [Fig. 6A];

[0030] [Fig. 6C] is a schematic perspective view of another element of the object of [Fig. 6A];

[0031] [Fig. 7A] is a schematic side perspective view of an element of the object shown in [Fig. 3]

[0032] [Fig. 7B] is a schematic perspective view of an element of the object of [Fig. 7A]; and,

[0033] [Fig. 7C] is a schematic perspective view of another element of the object of [Fig. 7A];

[0034] [Fig. 1] partially shows a twistable axle structure 10 of a motor vehicle obtained according to a usual method. Also, it is inscribed in an orthogonal reference frame X, Y, Z, in which the X axis extends in a longitudinal front-rear direction of the motor vehicle, oriented towards the rear; the Y axis extends in a transverse direction of the vehicle, oriented from left to right; and the Z axis extends in a vertical direction, oriented away from the ground.

[0035] Also, it has two opposite suspension arms, a right arm 12, a left arm 14, and a cross member 16 connecting the two arms 12, 14 together. The two suspension arms 12, 14 have, at their end, towards the front of the vehicle in the -X direction, each a socket 18 allowing the two articulated arms to be mounted on the body of the vehicle. Also, on the opposite side, the arms 12, 14 have wheel supports 20.

[0036] Furthermore, the cross member 16 is tubular and here, curved in an arc. It has two ends opposite each other 22, 24 connected in a T-shape respectively to the two opposite suspension arms 12, 14. Furthermore, its section is oblong at its ends and it varies from one end 22 to the other 24.

[0037] To do this, the two ends 22, 24 are stamped and cut so as to provide two opposite notches to form a seat suitable for receiving the arms 12, 14. The cross member 16 and the arms are then welded together at the joint defined by the seat. The two suspension arms 12, 14 are then rigidly connected by the cross member 16.

[0038] The manufacturing method according to the invention makes it possible to connect the same type of cross member to suspension arms of different sections.

[0039] Thus, [Fig. 3] partially illustrates, seen from above, a left arm of small section 26 connected to a crosspiece according to the invention 28 by means of a first sleeve 30. The crosspiece 28 has an end 29 fitted into the first sleeve 30. And [Fig. 2] represents, also seen from above, a left arm of large section 32 connected to the end 29 of a crosspiece 28 according to the invention by means of a second sleeve 34.

[0040] The two crosspieces according to the invention 28 are completely identical and they have the same profile and consequently, the same section, in particular at the level of their end 29 of connection to the two sleeves 30, 34.

[0041] The two types of sleeve 30, 34 which make it possible to connect the small-section arms 26 or the large-section arms 32 to the crosspiece 28 will be described in detail below. [Fig. 4] shows in detail, seen from the inside of the arm 32 for example, shown in [Fig. 2], a cylindrical connecting end 36 of the second sleeve 34. This cylindrical connecting end 36 of the second sleeve 34 has the same section as the cylindrical connecting end 38 of the first sleeve 30 illustrated in [Fig. 3]. This section is oblong and extends along the X axis.

[0042] Also, the cylindrical connecting end 36 has a free edge 40 ending in a straight looped edge 42 which defines a mean plane.

[0043] In [Fig. 5], we find the connecting end 36 of the second sleeve 34, according to the same section plane as that of [Fig. 2], but seen from the opposite side.

[0044] Therefore, we also find the end 29 of the crosspiece 28 fitted into the connecting end 36 of the second sleeve 34. Thus, it will be observed that the end 29 of the crosspiece 28 has a cross section substantially identical to the cross section of the connecting end 36 so as to be able to be engaged axially, without play in the vertical plane (X, Z).

[0045] Furthermore, it will be observed that the second sleeve 34 is formed of two second arched pieces, a second lower piece 44 and a second upper piece 46. These arched pieces are cut and stamped at an advantageous cost from metal plates.

[0046] The second lower arched part 44 has two second facing lower wings 48, 50, while the second upper arched part 46 has two second facing upper wings 52, 54.

[0047] The second lower and upper wings respectively facing 48, 50; 52, 54 are respectively connected two by two by welding to form the second sleeve 34. To do this, the two second lower wings facing 48, 50 each have a double second S-shaped deformation towards the outside to reveal two second clearances 56, 58. These two clearances make it possible to accommodate respectively the two second upper wings facing 52, 54 without modification of their curvature. Thus, the welds will be made at the joint between the wings 52, 48; 54, 50.

[0048] [Fig. 2], seen from above, shows the second upper arched part 46 of the second sleeve 34. Also, it has a second upper middle portion in a point 60 in the extension of a second upper cylindrical portion 61. Conversely, the second sleeve 34 includes the second lower arched part 44, here hidden, and which has a second lower middle portion in a point 62 opposite the second upper middle portion 60 and in the extension of a second lower cylindrical portion 63.

[0049] It will be observed that the first sleeve 30 is made in the same way, as will be explained below. Also, the identical parts will have the same reference assigned a prime sign: “'”.

[0050] We will also refer to [Fig. 7A], [Fig. 7B] and [Fig. 7C] in order to describe firstly the design and production of the first type of sleeve 30 illustrated in [Fig. 3] and adapted to the small section arm 26.

[0051] [Fig. 7C] shows the first lower arched part 44' of the first sleeve 30. It has cylindrical symmetry. It shows the first lower cylindrical portion 63' and the two first facing lower wings 48', 50'. Also shown is the first lower pointed middle portion 62', in the axial extension of the first lower cylindrical portion 63' and opposite a first lower straight edge 64'. Furthermore, opposite the first lower straight edge 64', the two facing lower wings 48', 50' have two first opposite lower curved edges 66', 68' converging towards the lower middle portion 62'.

[0052] [Fig. 7B] shows on the opposite side the first upper arched part 46'. It is also of cylindrical symmetry and [Fig. 7B] shows the first upper cylindrical portion 6T and the two first upper wings opposite 52', 54' as well as the first upper middle portion in a point 60' in the axial extension of the first upper cylindrical portion 61', opposite a first upper straight edge 70'.

[0053] Furthermore, opposite the first upper straight edge 70', the two facing upper wings 52', 54' have two opposite first upper curved edges 72', 74'.

[0054] Furthermore, the first upper arched part 46' has a first reinforcing rib 68' which extends axially in the first upper cylindrical portion 6T and tapers into the first upper middle portion at a point 60'.

[0055] Thus, the first lower arched piece 44' and the first upper arched piece 46' are connected to each other by their wings 48', 50'; 52', 54' as indicated above to result in the first type of sleeve 30 illustrated in [Fig. 7A],

[0056] Thus, the first two lower curved edges 66', 68' and the first two upper curved edges 72', 74' come in the extension of each other, so as to form two opposite arc-shaped notches 76', 78' joining the first two pointed middle portions 60', 62'. This forms a first seat 80'. Conversely, the first upper cylindrical portion 6T and the first lower cylindrical portion 63' together form a first connecting end 36'. This first connecting end 36' is substantially cylindrical.

[0057] We will now refer to [Fig. 6A], [Fig. 6B] and [Fig. 6C] illustrating the design and construction of the second type of sleeve 34 illustrated in [Fig. 2] and adapted to the large-section arm 32. It will be observed that the construction is identical to that of the first type of sleeve 30, and that only the design varies significantly. Thus, [Fig. 6C] shows the second lower arched part 44 of the second sleeve 34. It also has cylindrical symmetry. It shows the second lower cylindrical portion 63 and the two second lower wings facing each other 48, 50. The second lower cylindrical portion 63 is identical to the first lower cylindrical portion 63' of the first lower arched part 44'.

[0058] Also appearing in [Fig. 6C] is the second lower middle portion in a point 62, in the axial extension of the second lower cylindrical portion 63 and opposite a second lower straight edge 64. Also, this second lower middle portion in a point 62 has a transverse notch. Consequently, it is substantially shorter than the first lower middle portion in a point 62'.

[0059] Opposite the second lower straight edge 64, the two second facing lower wings 48, 50 have two second opposite lower curved edges 66, 68 converging towards the second lower middle portion 62.

[0060] [Fig. 6B] shows on the opposite side the second upper arched part 46. It shows a second upper cylindrical portion 61 and the two second upper wings opposite 52, 54. Here too, the second upper cylindrical portion 61 is identical to the first upper cylindrical portion 61' of the first upper arched part 46'.

[0061] On the other hand, the second upper middle portion at a point 60 extends in a stepped manner relative to the second upper cylindrical portion 61 which it extends opposite the second upper straight edge 70. In other words, according to a projection onto the plane defined by the second upper edge 70, the radius of curvature of the upper middle portion at a point 60 is substantially greater than the radius of curvature of the second upper cylindrical portion 61. And therefore, the radius of curvature of the second upper middle portion at a point 60 is greater than the radius of curvature of the first upper middle portion at a point 60'.

[0062] Consequently, opposite the second upper straight edge 70, the two second facing upper wings 52, 54 have two second opposite upper curved edges 72, 74, with a radius of curvature greater than that of the two first opposite upper curved edges 72', 74'.

[0063] And opposite the second upper straight edge 70, the two second upper wings opposite each other 52, 54 have two second opposite upper curved edges 72, 74 whose radius of curvature is greater than that of the first two opposite upper curved edges 72', 74' of the two first upper wings opposite each other 52', 54'.

[0064] Also, the second upper arched part 46 has a second reinforcing rib 68 which extends axially in the second upper cylindrical portion 61 and tapers into the second upper middle portion at a point 60.

[0065] The second lower arched piece 44 and the second upper arched piece 46 are then connected to each other by their wings 48, 50; 52, 54 to result in the second type of sleeve 34 illustrated in [Fig. 6A],

[0066] The two second lower curved edges 66, 68 and the two second upper curved edges 72, 74 come in the extension of each other, so as to form two opposite arc-shaped notches 76, 78 joining the two first pointed median portions 60, 62, thus forming a second seat 80.

[0067] Conversely, the second upper cylindrical portion 61 and the second lower cylindrical portion 63 together form the second connecting end 36, illustrated in [Fig. 4] and [Fig. 5]. It is substantially cylindrical.

[0068] Thus, it appears clearly in [Fig. 6A] that the two second pointed median portions 60, 62 are spaced apart from each other by a distance greater than that which separates the two first pointed median portions 60', 62' of the first sleeve 30. And therefore, the second seat 80 is wider than the first seat 80' of the first sleeve 30 appearing in [Fig. 7A]

[0069] Thus, with these two types of sleeve 30, 34, in accordance with the manufacturing method according to the invention, pairs of first arms of small section are provided, adapted to connect the two wheels and the body of a first type of vehicle, and pairs of second arms of a second section greater than said first section, adapted to connect the two wheels and the body of a second type of vehicle. Also, a plurality of the same crosspieces as described above are provided.

[0070] According to the invention, for the first type of vehicle, pairs of first sleeves 30 are provided, each having a first connecting end 36'. The end of the crossmembers is fitted inside the connecting end 36' and a weld bead is applied to the joint between the end of the crossmember and the first sleeve 30. Also, on the other hand, the first receiving seat 80' can receive a small arm, perpendicular to the crossmember. A weld bead is then applied straddling the sleeve and the arm at the first receiving seat 80'. Each of the crossmembers is then equipped with a pair of first sleeves 30.

[0071] For the second type of vehicle, pairs of second sleeves 34 are provided, each having a connecting end 36, and the end of the cross members is fitted inside the connecting end 36. Then a weld bead is applied to the joint between the end of the cross member and the second sleeve 34.

[0072] Also, on the other hand, the second receiving seat 80 can receive a large arm. A weld bead is then applied across the sleeve and the arm at the second receiving seat 80. Each of the crosspieces is also equipped with a pair of second sleeves 34.

[0073] In this way, it is possible to manufacture twistable axle structures for two significantly different motor vehicles, equipped with the same type of cross member.

[0074] Furthermore, the method is not limited to the implementation of two types of sleeve. It is envisaged to implement pairs of arms of an intermediate section and consequently to produce sleeves whose connecting end has an intermediate section.

Claims

CLAIMS

1. A method of manufacturing twistable axle structures for a motor vehicle comprising the following steps: - pairs of first arms (26) of a first section adapted to connect the two wheels and the body of a first type of vehicle and pairs of second arms (32) of a second section greater than said first section, adapted to connect the two wheels and the body of a second type of vehicle; - a plurality of crosspieces (28) are provided to be able to connect together respectively the arms of said pairs of arms (26; 32); characterized in that the crosspieces (28) of said plurality of crosspieces are all identical and in that the following are further provided: - pairs of first T-shaped coupling sleeves (30) each having a connecting end (36') with said crosspieces (28) and opposite a first receiving seat (80') of a first width to be able to receive arms of said pairs of first arms (26); and, - pairs of second T-shaped coupling sleeves (34) each having a connecting end (36) with said crosspieces (28) and opposite a second receiving seat (80) of a second width greater than said first width, to be able to receive arms of said pairs of second arms (32).

2. Manufacturing method according to claim 1, characterized in that said connecting end (36, 36') has a free edge closed on itself and in that each of said crosspieces (28) is fitted inside said free edge.

3. Manufacturing method according to claim 2, characterized in that said free edge and the crosspiece are connected to each other by a first weld bead.

4. Manufacturing method according to any one of claims 1 to 3, characterized in that each of said sleeves (30, 34) has, opposite the fitting end, two facing notches to form the seat (80, 80').

5. Manufacturing method according to claim 4, characterized in that said two notches (76, 78) define a notched edge and in that said notched edge is connected to said arms (26, 32) by a second weld bead.

6. Manufacturing method according to any one of claims 1 to 5, characterized in that each of said sleeves (30, 34) is formed of two arched pieces (44, 46) welded together.

7. Manufacturing method according to claim 6, characterized in that each of said two arched pieces (44, 46) comprises a portion of cylindrical symmetry (61, 63) having two facing wings (48, 50; 52, 54) defining a straight edge (64, 70), and a median portion (60, 62) extending in a point opposite said straight edge.

8. Manufacturing method according to claim 7, characterized in that one (46) of said two arched parts of each of said second T-shaped coupling sleeves has a median portion (60) offset from said cylindrical portion (61).

9. Manufacturing method according to claim 8, characterized in that the other (44) of said two arched pieces of each of said second T-shaped coupling sleeves has a notched pointed median portion (62).

10. Manufacturing method according to any one of claims 1 to 9, characterized in that: - at least pairs of third arms of a third section greater than said second section are provided, adapted to connect the two wheels and the body of at least one third type of vehicle; - at least pairs of third T-shaped coupling sleeves are provided, each having a connecting end with said crosspieces and opposite a third receiving seat of a third width to be able to receive arms of said pairs of third arms.

11. Kit for manufacturing a twistable axle structure for a motor vehicle, characterized in that it comprises: - a pair of first arms (26) of a first section, and a pair of first T-shaped coupling sleeves (30) each having a first seat receiving end (80') of a first width to be able to receive the first arms (26) and opposite a first connecting end (36'); - a pair of second arms (32) of a second section greater than said first section, and a pair of second T-shaped coupling sleeves (34) each having a second receiving seat (80) of a second width greater than said first width to be able to receive the second arms (32) and opposite a second connecting end (36) identical to said first connecting end (36'); and, - a crosspiece for being able to connect together the first connecting ends (36') of said first T-coupling sleeves (30), or for being able to connect together the second connecting ends (36) of said second T-coupling sleeves (34).

12. A twistable axle structure of a motor vehicle comprising: - a pair of first arms (26) of a first section adapted to connect the two wheels and the body of a first vehicle, or a pair of second arms (32) of a second section greater than said first section, adapted to connect the two wheels and the body of a second vehicle; - a crosspiece (28) for connecting together the first arms (26) or the arms of said pair of first arms (26; 32); characterized in that it further comprises: - a pair of first T-shaped coupling sleeves (30) having a connecting end (36') with said crosspiece (28) and opposite a first receiving seat (80') of a first width to be able to receive arms of said pair of first arms (26); or, - pairs of second T-shaped coupling sleeves (34) each having a connecting end (36) with said crosspieces (28) and opposite a second receiving seat (80) of a second width greater than said first width, to be able to receive arms of said pairs of second arms (32).

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