Process for assembling a shaft and a flange for the support of a rotating basket of a washing machine, and assembly thus obtained

Abstract: A process for assembling a supporting and driving shaft (3) of a rotating basket for a washing machine with a flange (1) for coupling the shaft to the basket includes: formation of a cylindrical seat (2) in said flange which is able to receive a first portion (8) of the larger diameter of the said shaft (3), said cylindrical seat being frontally provided with a hole (4) having a reduced diameter for passage of a second portion (9, 10, 11) of said shaft; insertion of said shaft (3) in said seat (2) in such a way that said first portion abuts against an edge (6) of said hole (4); swaging of at least one part of said second portion (9, 10 , 11) against said edge (6) of hole (4), so that said edge (6) of hole (4) is closed between said first portion (8) and said second swaged portion (9, 10, 11) of the shaft.

Description: The present invention refers to a process for assembly a shaft and a flange for the support of a rotating basket of a washing machine, particularly but not exclusively of the type with topside loading, and the shaft-flange assembly thus obtained. In the traditional laundry washing machines, the flange-shaft assembly that supports the rotating basket is normally obtained by die-casting the flange on a worked shaft having an incorporated rolled bushing with which, once the shaft has been assembled with the flange, a seal cooperates to guarantee the water-proof sealing. As an alternative, the flange is obtained by pressing a sheet of Inox steel, so as to form a central protruding bulge for water sealing, and on said bulge the worked shaft is butt-welded. This solution is for instance employed in laundry washing machines with topside loading. These assemblage systems prove to be rather laborious and, moreover, do not guarantee a perfect positioning and alignment of the shaft. This second aspect is of particular importance in washing machines with topside loading, in which the basket is sustained by two opposing shafts, whose perfect axial alignment is essential for correct operation of the machine and for guaranteeing the reliability of the rotating mechanical components. Examples of the above cited prior art are disclosed, for instance, in documents FR-A-2.493.885, FR-A-2.140.037 and EP-A-0 214 039. In view of the described state of the art, an object of this invention is to provide a process for assembling the shaft to the flange that is simple and that guarantees a better positioning and alignment of the shaft, In accordance with the present invention, such an object is reached by a process for assembling a supporting and driving shaft for a rotating basket of a washing machine with a flange for coupling the shaft to the basket, having the characterizing features of the appended claim 1, and by a washing machine having the characterizing features of the appended claim 7. The process according to the invention, besides being simple, guarantees a perfect positioning and alignment of the shaft. The features of the present invention will appear evident from the following detailed description of an embodiment thereof, illustrated as a non-limiting example in the attached drawings, in which: Figure 1 is a front view of a flange before assemblage with a shaft; Figure 2 is a section view according to line II-II of Figure 1; Figure 3 is a front view of a shaft before assemblage with the flange of Figures 1 and 2; Figure 4 is a side view of the shaft; and Figure 5 is a section view, analogous to the one of Figure 2, of the flange and the shaft put together. With reference to Figures 1 and 2, there is shown a flange 1 for coupling of a respective supporting shaft 3, shown in Figures 3 and 4, with a rotating basket (not shown) of a laundry washing machine. Flange 1 is preferably of metal, in particular Inox steel, and is obtained by pressing and blanking. Flange 1 is shaped so as to form a cylindrical seat 2 for accommodating shaft 3. The cylindrical seat 2 is open in the back and, in the front, it is provided with a circular hole 4; an edge 6 of the hole 4 forms a shoulder having a small diameter with respect to the internal diameter of the cylindrical seat 2. Along the edges of the hole 4 four relieves 5 are provided, obtained by blanking, arranged in a circumferential succession. Along the periphery of the flange 1 there is also provided a circumferential succession of holes 7 for fastening the flange to the basket by means of screws. Shaft 3 comprises a portion 8 of larger diameter, substantially corresponding to the internal diameter of the cylindrical seat 2, followed by a portion 9 having a smaller diameter, substantially equal to the diameter of the hole 4 in the cylindrical seat 2, by a fust 10 having an even smaller diameter on which, when in use, a ball bearing is keyed and ends with a tang 11 having an even smaller diameter provided with an internal threaded hole. For assembling the shaft with the flange, the shaft is first inserted into seat 2 so that the tang 11, the fust 10 and the portion 9 come out frontwise from the flange by passing through the hole 4. Successively, by means of a proper machine tool, portion 9 is pressed up against edge 6 of the hole 4. The material that constitutes portion 9, once upset, determines the formation of a ring 12 (Figure 5) that cooperates with portion 8 of the shaft to block the shaft 3 into flange 1. The material that constitutes portion 9 of the shaft, during the upsetting, also fills the relieves 5, forming an equal number of teeth 13 which, in this way, prevent the rotation of the shaft with respect to the flange. Thank to the process of assemblage in accordance with the invention the correct position and alignment of the shaft is guaranteed.

Claims: Process for assembling a supporting and driving shaft (3) for a rotating basket of a washing machine with a flange (1) for coupling the shaft to the basket, comprising, in any order, the steps of a) coupling the shaft to the flange, in a way that said shaft (3) is blocked into the flange (1) and any rotation of the shaft (3) with respect to the flange (1) is prevented, b) fastening the flange (1) to the basket, characterized in that step a) includes: formation of a cylindrical seat (2) in said flange which is able to receive a first portion (8-9) of larger diameter of said shaft (3), said cylindrical seat being frontally provided with a smaller diameter hole (4) for passage of a second portion (9,10,11) of said shaft (3); formation of at least a material relief (5) on an inner surface of said seat (2), said relief (5) being destined to engage with a tooth (13) formed on an outer surface of said first portion (8,9) of the shaft (3); insertion, after said relief (5) has been formed, of the shaft (3) into said seat (2), so that a surface of said first portion (8,9) abuts against an edge (6) of said hole (4) and said second portion (9,10,11) comes out of said hole (4); swaging of at least one part of said second portion (9,10,11) against said edge (6) of the hole (4), so that said edge (6) of the hole (4) is tightly held between said surface of said first portion (8,9) and said swaged part of said second portion (9,10,11) of the shaft (3); formation of said tooth (13) on said first portion (8,9) of the shaft (3), after the latter has been received by said seat (2) and during the swaging of said one part of said second portion (9,10,11), said tooth being formed by swaged material of at least one part of said first portion (8,9) that fills up said relief (5), for preventing any rotation of the shaft (3) with respect to the flange (1). Process according to claim 1, characterized in that the swaging of said first portion (8,9) involves only a sub-portion of said first portion of the shaft (3), adjacent to said surface of said first portion (8,9). Process according to claim 2, characterized in that the swaging of said second portion (9,10,11) involves only a sub-portion of said second portion of the shaft (3), adjacent to said sub-portion of said first portion (8,9). Process according to claim 1, characterized in that said relief (5) is formed in said edge (6) of the hole (4) of the cylindrical seat (2) of the flange (1). Process according to claim 1, characterized in that a plurality of relieves (5) and a plurality of teeth (13) are formed. Process according to claim 1, characterized in that the swaged material of said second portion (9,10,11) remains outside said flange (1) and/or said hole (4). Washing machine comprising a rotating basket, a shaft and flange assembly (1,3) for supporting and driving said basket, the flange (1) being fixed to the basket and the shaft (3) being fixed to the flange (1), means (12-13) being provided for preventing any rotation of the shaft (3) with respect to the flange (1), characterized in that said flange (1) is provided with a cylindrical seat (2), able to receive a first portion (8,9) of larger diameter of said shaft (3) and having a smaller diameter hole (4) for the passage of a second portion (9,10,11) of the shaft (3), said second portion (9,10,11) of the shaft (3) comprises a ring (12) that co-operates with said first portion (8,9) of the shaft (3) to lock the edge (6) of said hole (4), said means (12,13) comprise at least a material relief (5) formed on an inner surface of said seat (2) and a tooth (13) formed on an outer surface of said first portion (8,9) of the shaft (3), said tooth being engaged in said relief (5), whereby said relief (5) is formed in said seat (2) before the latter receives said first portion (8,9) of the shaft (3), and said tooth (13) is formed on said first portion (8,9) of the shaft (3) after the latter has been received by said seat (2) said tooth (13) being formed by swaged material of a sub-portion of said first portion (8,9) that fills up said relief (5). Washing machine, according to claim 7, characterized in that said ring (12) is formed by swaged material of a sub-portion of said second portion (9,10,11). Washing machine, according to claim 7 or 8, characterized in that a first surface of said edge (6) defines a shoulder which has a smaller diameter than the internal diameter of said seat (2), a surface of said first portion (8) abutting against said shoulder. Washing machine, according to claim 7 or 8, characterized in that the external diameter of said ring (12) is greater than the diameter of said hole (4). Washing machine, according to claim 7 or 8, characterized in that said ring (12) abuts against a second surface of said edge (6), the latter being interposed between said surface of the first portion (8) and said ring (12), Washing machine, according to claim 8, characterized in that the swaged material of said sub-portion of said second portion (9,10,11) remains outside said flange (1) and/or said hole (4). Washing machine, according to at least on of the previous claims, characterized in that a plurality of relieves (5) and a plurality of teeth (13) are provided. Washing machine, according to the previous claim, characterized in that said relieves (5) are arranged in a circumferential succession along said edge (6) of said hole (4).

Inventors: PAROLINI FIORENZO, REBOLINI ERNESTO, TORNARI GIUSEPPE, PAROLINI, FIORENZO, TORNARI, GIUSEPPE
Applicants: PHILCO ITALIANA, PHILCO ITALIA S.P.A.
Application year: 1997
Main classification: D06F37
IPC codes: D06F37