Rotating and sealed bearing assembly of a first member rotating in a second member

Abstract: This invention relates to a rotating and sealed bearing assembly of a first member (12) rotating in a second member (10), comprising a bearing outer track structure (28) mounted in a bore (11) of the second member traversed by the first member (12) and bearing a lip seal (40), the bearing inner track (24) being formed on the first member (12), the bearing outer track structure being made of a sheet steel backing plate (28) shaped in order to a present an intermediate zone of rounded profile (26) forming the bearing outer track. According to the invention, the intermediate zone (26) is extended on one side by a first end zone (30) extending axially and on the other side by a second end zone (36) extending axially, the second end zone (36) being connected to the intermediate zone (26) by a mediane zone (34) extending radially.

Description: The present invention relates to a rotating and sealed bearing assembly of a first member rotating in a second member, more particularly, but not exclusively, of a rotating member of a distribution valve for a servo-mechanism, notably for vehicle power-assisted steering, rotating in a housing of a hydraulic distributor, the assembly being of the type comprising : a bearing outer track structure mounted in a bore of the second member traversed by the first member and having a lip seal, the bearing inner track structure being formed on the first member. An assembly of this type is described in the document EP-A-0 258 094. In this document, the structure of a bearing outer track is constituted by a backing plate in sheet steel shaped in order to present an intermediate zone of rounded profile forming the bearing outer track which extends, on one side, folded back, by a first zone with radial end and, on the other side, by a second zone with axial end with the lip seal interacting with the first member. The document EP-A-0 291 608, corresponding to the preamble of the main claim, discloses a bearing assembly in which the bearing outer track is made of three pieces of sheet steel. The structures disclosed in these known documents necessitate a stepped bore in the second member, which increases the manufacturing difficulty and cost, and which increases also the overall dimensions of the assembly. The object of the present invention is to provide an assembly of the above-mentioned type, of rugged and light design, with low manufacturing and assembling costs, suitable for very considerable mass production, and enabling a compact design without altering hardiness. To do this, according to a feature of the invention, the bearing outer track is made of a sheet steel backing plate, the second end zone of the backing plate forming the bearing outer track extends axially in the same directions as the first end zone and is joined with the latter, the sheet steel backing plate defines and annular chamber between the bearing outer track and the bore of the second element, an annular groove is formed in this bore and connected by a duct to a reservoir of hydraulic fluid or to a source of hydraulic fluid under pressure, and openings are made in the backing plate in order to communicate the annular chamber with the annular groove and with the inner part of the bore. Another object of the present invention is to provide an assembly of the type considered enabling static sealing of the assembly to be ensured axially, on both sides, besides dynamic sealing by the lip seal, without excessive manufacturing costs. To do this, according to another feature of the invention, the second end zone bears in addition a static seal interacting in engagement contact with the bore formed in the second element, the said static seal and the lip seal being moulded with advantage on an end turned back radially of the second end zone. Other features and advantages of the present invention will become evident from the following description of an embodiment, given by way of illustration but in no way limiting, made with reference to the accompanying drawing, in which : The sole Figure is a partial view in longitudinal section of a rotating hydraulic distributor for power-assisted steering having a rotating and sealed bearing assembly according to the invention. The input part of a hydraulic distributor for power-assisted steering of vehicles of the type described in the document EP-A-0 181 797, in the name of the applicant, is shown diagrammatically in the Figure. Such distributor is usually mounted in a housing 10 formed with a bore 11 inside through which extends an input shaft 12 intended to be connected to the steering wheel of a motor vehicle. The input shaft 12 is coupled to an output shaft 14, hydraulically by means of star-shaped valve device (not shown) and mechanically by a lost travel flexible coupling having a set of C-shaped springs 16. According to the invention, a rotating and sealed bearing assembly 20 is provided between the housing 10 and the input-shaft 12. The bearing balls 22 are located between a bearing inner track 24 formed on the output shaft 12, and a bearing outer track constituted by an intermediate zone of rounded profile 26 in a sheet steel backing plate 28. The intermediate zone 26 is extended, on one side, by a first end zone 30 extending axially, this first end zone, in the illustrated example, being joined with the intermediate zone 26 by a frustoconical part 32 of the sheet steel backing plate 28 in order for the diameter of the first end zone to be greater than the average diameter of the intermediate zone 26. The intermediate zone 26 is extended, on the other side, by a median zone 34 extending radially outwardly, which itself is extended axially in the same direction as the first end zone 30. This second end zone 36 is terminated by an end section 38 extending radially inwardly on which a structure of lip seal 40 is moulded. In the preferred embodiment shown, the second end zone 36 extends some distance axially, radially, inwardly from the wall of the bore 11, a static tubular seal 42, with advantage moulded in a single piece with the lip seal 40, being inserted compressed between the second end zone 36 and the wall of the bore 11 so as to insulate, dynamically as well as statically, the inner part of the bore 11 from the outside of the housing 10. In order to increase the hardiness of the sheet steel backing plate 28, the first and second end zones 30 and 36 are joined, and the first end zone 30 comes to bear axially against the end section 38 turned back radially inwardly of the second end zone 36. The sheet steel backing plate 28 defining the bearing outer track defines also an annular chamber 44 between the bearing outer track and the wall of the bore 11. According to an advantageous feature of the invention, this annular chamber 44 takes a part either in the feeding of the distributor from a source of hydraulic fluid under pressure or in the removal of hydraulic fluid to a reservoir. For this purpose, an annular groove 46 is formed in the bore 11, between the median part 34 and the second end zone 36, and a drilling 48 in the housing 10 opens in the annular groove 46 and establishes a duct for hydraulic fluid from a source or to a reservoir. Openings 50 in the sheet steel backing plate 28 allow the hydraulic fluid to flow though the bearing outer track structure from or to the inner part of the bore 11 and the distributor. Although the present invention has been described relative to a particular embodiment, it is not in fact limited thereby but is, on the contrary, amenable to modifications and variations which will be apparent to the person skilled in the art, particularly concerning the detail forms and the respective dimensions of the end zones 30 and 36.

Claims: Rotating and sealed bearing assembly of a first member (12) rotating in a second member (10), comprising a bearing outer track structure (28) mounted in a bore (11) of the second member traversed by the first member (12) and bearing a lip seal (40), the bearing inner track (24) being formed on the first member (12), the bearing assembly comprising a plurality of bearing balls (22), the bearing outer track structure being made of sheet steel shaped in order to present an intermediate zone of rounded profile (26) forming the bearing outer track, the intermediate zone (26) being extended on one side by a first end zone (30) extending axially and on the other side by a second end zone (36) extending axially, the second end zone (36) being connected to the intermediate zone (26) by a median zone (34) extending radially, characterized in that the bearing outer track is made of a sheet steel backing plate (28); the second end zone (36) extends axially in the same direction as the first end zone (30) and is joined with the first end zone (30); the sheet steel backing plate (28) defines an annular chamber (44) between the bearing outer track (28) and the bore (11) of the second element (10); an annular groove (46) is formed in the bore (11) of the second element (10), this annular groove (46) being connected by a duct (48) to a reservoir of hydraulic fluid or to a source of hydraulic fluid under pressure; and openings (50) are made in the sheet steel backing plate (28) in order to communicate the annular chamber (44) with the annular groove (46) and with the inner part of the bore (11). Assembly according to claim 1, characterized in that the second end zone (36) bears a static seal (42) interacting in engagement contact with the bore (11). Assembly according to any of preceeding claims, characterized in that the lip seal (40) is moulded on an end turned back radially (38) of the second end zone (36). Assembly according to Claim 2 or Claim 3, characterized in that the lip seal (40) comprises an elongated peripheral part forming said static seal (42). Assembly according to claim 3, characterized in that the first end zone (30) comes to bear axially against the end section (38) turned back radially inwardly of the second end zone (36).

Inventors: GUASCH ESTEVE CORTES C O BENDI, GUASCH, ESTEVE CORTES, C/O BENDIX EUROPE DRANCY
Applicants: BENDIX ESPANA, BENDIX ESPANA S.A.
Application year: 1990
Main classification: F16C33
IPC codes: F16C19, F16C33