METHOD FOR ASSEMBLING THE TERMINAL PORTION OF A MOTOR VEHICLE WHEEL AXLE SUPPORT-MEMBER, AND THE TERMINAL PORTION PRODUCED BY THIS METHOD

Abstract: The method enables certain components such as two half-shells (3), a hub (5) and flange (7) to be assembled for the purpose of forming a wheel axle terminal (1) and consists essentially of the following operations in succession: - positioning one of the half-shells (3) on the other so that their respective edges (11 and 13) and respective semicylindrical end portions (12) mate in order to form a cylindrical seat (4); - welding said half-shells (3) together along edges (11 and 13); - inserting said hub (5) into the cylindrical seat (4) and welding the axial ends of this latter to the seat (4) by circumferential butt welds; - positioning the flange (7) on an end portion (6) of the hub (5) which emerges from the seat (4), and welding the axial end of said portion (6) circumferentially by a butt weld to the flange (7).

Description: This invention relates to a method for assembling the terminal portion of a motor vehicle wheel axle support member. The invention also relates to a terminal portion produced by said method. Terminal portions of the aforesaid type are known to comprise an arm, at one end of which a seat is provided for a wheel carrier hub which is rigidly fixed to an annular flange. The said components are currently assembled using conventional arc welding, by which a structure is produced with good mechanical characteristics but requiring subsequent machine finishing, in that while welding the components, deformation occurs by material shrinkage, which is typical of this work. The finishing which is required after welding consists of restoring the required dimensional tolerances of the structure using appropriate machine tools. Such finishing operations obviously increase production costs and involve relatively lengthy operation times. Another welding method currently finding increasing use, mainly because it can be automated, is high-density energy welding using for example laser, electron beam or miniplasma technology. However, this welding method requires the various components of the terminal portion to make precise mutual contact in order to form reliable weld seams which are free from defects and are of maximum possible extension. An object of the present invention is to provide a method for assembling the terminal portion of a motor vehicle wheel axle support member, which is free from the aforesaid drawbacks and which in particular enables high-density energy to be used. A further object of the present invention is, using said method, to provide a terminal portion having excellent mechanical characteristics and low production costs. Further objects and disadvantages of the present invention will be apparent from the description given hereinafter. The invention provides a method for assembling the terminal portion of a motor vehicle wheel axle support member comprising: a hub: an annular flange; and two substantially U-section half-shells each having a semicylindrical end portion arranged orthogonal to the longitudinal axis of said half-shell, characterized by comprising the following operations in succession: positioning one of said two half-shells on the other one to form a cylindrical seat by means of said end portions, and such that the edges of said one half-shell mate with the corresponding edges of the other one; welding said half-shells together along said edges; inserting said hub into said seat in such a manner that an end portion of said hub remains external to said seat; welding said hub to said seat by a circumferential butt welding operation at the two axial ends of said hub; positioning said flange on said portion of said hub; and welding said flange onto said portion of said hub by a circumferential butt welding operation at the free axial end portion of said hub. The present invention also provides said terminal portion of a the support member as defined in claim 4. The invention will be more apparent from the description of a preferred embodiment thereof given hereinafter with reference to the accompanying drawings, in which: Figure 1 is an exploded perspective veiw of the various components of a terminal portion of an automotive wheel axle support member before assembly; Figures 2 to 4 show three separate stages of the method for assembling the components shown in Figure 1; and Figure 5 is a perspective view of the terminal portion after assembly. In Figure 1, the reference numeral 1 indicates overall the terminal portion of a motor vehicle wheel axle support member, hereinafter called "terminal" , which is of the type comprising an arm 2 consisting of two half-shells 3 and in which, in proximity to an end thereof there is defined, when in use, a cylindrical seat 4 engaged by a wheel carrier hub 5, on an end portion 6 of which, external to the seat 4, there is fixed an annular flange 7. The half-shells 3 are substantially identical and are constructed of pressed plate. Specifically, each half-shell 3 comprises a central portion 8 of U-section having its longitudinal edges bent outwards at a right angle to define two respective longitudinal flanges 11. Each half-shell 3 also comprises and end portion 12 smoothly joined to the portion 8 and extending semicylindrically with its longitudinal axis orthogonal to that of the portion 8. From an edge parallel to the longitudinal axis of the portion 12 there extends a flange 13 which is coplanar with the flanges 11 of the portion 8. It should be noted that the length of the portion 12 is equal to the width of the portion 8 including the flanges 11. On placing the half-shells 3 together, the portion 12 define said seat 4, which has an inner diameter equal to or slightly greater than the outer diameter of the hub 5. On fitting these pieces together, the flanges 11 and flanges 13 of the two half-shells 3 come into mutually aligned contact. The end portion 6 of the hub 5 has an outer diameter less than that of the part of the hub 5 housed in the seat 4. The portion 6 has the same length as the flange 7. The method for assembling the terminal 1 comprises essentially the following operations in succession: one half-shell 3 is positioned on the other so that the flanges 11 and 13 and the portion 12 of one mate with those of the other; each flange 11 and 13 of one half-shell 3 is welded to the corresponding flange 11 and 13 of the other half-shell 3 by a high-density energy welding method, for example of laser type, to form respective weld seams (Figure 2) on the flanges 11 and 13; the hub 5 is inserted into the seat 4 such that its portion 6 is external to said seat 4; again using high-density welding, the hub 5 is welded along the seat 4 so as to form a circumferential butt weld seam 15 along each of the axial ends of the hub 5 (Figure 3); the flange 7 is positioned on the portion 6 of the hub 5; and again using the said welding method, the flange 7 is welded along the portion 6 to form a circumferential butt weld seam along the free axial end of the portion 6. This welding by means of a high-density energy source can be implemented using for example laser, electron beam or miniplasma technology. This technology enables a continuous weld to be made which gives the terminal 1 excellent mechanical strength. The advantages of the aforesaid method and of the terminal 1 obtained by said method are apparent from an examination of their characteristics. In this respect, using said method a structure is obtained with excellent mechanical characteristics requiring no subsequent machine finishing. In addition, the method enables the advantages offered by high density welding to be gained, the use of which obviates the deformation which occurs when using conventional welding methods. Thus when assembled, the structure has very narrow dimensional tolerances. It should be noted that the aforesaid assembly of the terminal 1 can be advantageously automated using a suitable robotized machine. This enables terminals to be produced in a relatively short time at low cost. The fact that the hub 5 and flange 7 are not of integral construction further increases the versatility of the terminal 1, with the result that flanges of different dimensions can be mounted according to requirements, and in addition the hub 5 can be welded into the seat 4 along both its axial ends, with all the advantages deriving therefrom in terms of mechanical strength. Finally, it is apparent that modifications can be made to the aforesaid operations involved in the method for assembling the terminal 1 and to the terminal itself, but without leaving the protective scope of the present invention.

Claims: A method for assembling the terminal portion of a motor vehicle wheel axle support member (1) comprising: a hub (5); an annular flange (7); and two substantially U-section half-shells (3) each having a semicylindrical end portion (12) arranged orthogonal to the longitudinal axis of said half-shell (3), characterized by comprising the following operations in succession: positioning one of said two half-shells (3) on the other one to form a cylindrical seat (4) by means of said end portions (12), and such that the edges (11 and 13) of said one half-shell (3) mate with the corresponding edges of the other one; welding said half-shells (3) together along said edges (11 and 13); inserting said hub (5) into said seat (4) in such a manner that an end portion (6) of said hub (5) remains external to said seat (4); welding said hub (5) to said seat (4) by a circumferential butt welding operation at the two axial ends of said hub (5); positioning said flange (7) on said portion (6) of said hub (5); and welding said flange (7) onto said portion (6) of said hub (5) by a circumferential butt welding operation at the free axial end portion (6) of said hub (5). A method as claimed in claim 1, characterized in that at least one of said welding operations is implemented using a high-density energy source. A method as claimed in claim 2, characterized in that said high-density energy source is selected from one of the followings: laser, electron beam, miniplasma. The terminal portion of a motor vehicle wheel axle support member produced according to the successive assembly operations defined in claim 1 and comprising: two substantially U-section half-shells (3) welded together to form an arm (2), each of said half-shells (3) having a semicylindrical end portion (12) arranged orthogonal to the longitudinal axis of said half-shell (3) and defining a cylindrical seat (4); a hub (5) housed in said seat (4); and an annular flange (7) mounted on an end portion (6) of said hub (5) which is external to said seat (4) whereby said half-shells (3) are welded toghether by: a first weld seam (14) formed along the mating edges (11 and 13) of said half-shells; a second circumferential butt weld seam (15) along the axial ends of said hub (5), between this latter and said seat; and a third circumferential butt weld seam (16) along the free axial end portion (6) of said hub (5), between this latter and said flange (7). The terminal portion as claimed in claim 4, characterized in that in each of said half-shells (3) said mating edges include a first pair of longitudinal flanges (11) extending from a U-section central portion (8) of said half-shell (3), and a second flange (13) extending from said end portion (12) orthogonal to said longitudinal flanges (11). The terminal portion as claimed in claim 5, characterized in that said first pair of flanges (11) are formed by bending the edges of said central portion (8) at a right angle. The terminal portion as claimed in claim 6, characterized in that each one of said half-shells (3) has said first pair of flanges (11) coplanar with said second flange (13).

Inventors: BALESTRINO, GIOVANNI, BRUNO, ALFONSO, CERRATO, EDILIO, RABINO, EDOARDO
Applicants: FIAT AUTO S.P.A.
Application year: 1988
Main classification: B60G7
IPC codes: B60G7