Seal for the hubs of vehicle wheels

Abstract: A seal for bearings of the hubs of vehicle wheels comprises a central body (14) having a seating recess for a spring (15), from which there extends an appendix (16) rigidly connected to a metal insert (18) driven onto the outer race (11) of the bearing; projecting from the appendix (16) is a lip (19) which provides a static seal against the outer race of the bearing, whilst two further lips (22 and 23) project from the body (14) to form a dynamic seal against the toroidally shaped surface (24) of the inner race (10); said lips (22) and (23) are oriented towards the outside of the bearing in order to exploit the centrifugal effect deriving during the operation from the rotation of said surface (24).

Description: The invention refers to a seal for bearings of the hubs of vehicle wheels as set out in the first part of claim 1. Recent generations of bearings applied to the hubs of the wheels offer very good operating performance, but these types are rather expensive so it is opportune to equip them with seals that ensure a sealing as safe as possible against infiltration of external agents like water, dirt, mud, to which the elements on which bearings are assembled are constantly subjected. Such seals, at the moment, though having at least two sealing lips, are designed so that such lips become easily worn-out and/or do not ensure a sufficient sealing in every operating condition of the bearing as the lips are not always correctly oriented and are not pressing on the surface of the element on which the sealing must be exerted (cf e.g. GB-A-2018914 or FR-A-2249573, respectively). DE-A-2841806 discloses a sealing device for bearing assemblies wherein two sealing lips bifurcate taking a Y-shaped arrangement in pressing against a surface of the bearing. Purpose of the invention is to overcome the above mentioned inconveniences and to propose a seal performing a better sealing both of static type (on the outer race) and of dynamic type (on the inner race), having such an orientation of the relating lips to improve the said sealing and to elongate the life of the seal and consequently of the same bearing also during very heavy operating conditions. For these and other purposes which will be better appreciated as the description follows, the invention proposes to provide a seal for bearings of the hubs of vehicle wheels comprising the features set out in the second part of claim 1. A description of the seal according to the invention will now follow. In a bearing fcr the hub of vehicle wheel which comprises a generally rotating inner race, a generally immovable outer race and two ball crowns retained by cages, the seal according to the invention is being assembled interposed between such elements. The above elements of the bearing are not described in detail as these are not the subject of the invention; their shapes and dimensions are merely examples, as they can assume any other configuration according to the utilisation without modifying the purposes and the advantages of the invention. The seal has a central body rigidly connected to a metal insert driven on the outer race. From the seal an appendix is extending which, after the assembly, is being compressed by pressing on the outer race, so as to ensure a good static seal thus avoiding that external agents that may infiltrate between the race and the insert, reaching the bearing. A dirt guard lip and three sealing lips are extending from the central body. The outer lip of said sealing lips is lengthened and flexible to allow a good sealing against the surface of the inner race of the bearing also in case misalignments should take place during assembly or during operation. Between outer lip and main lip of said sealing lips, a grease-containing chamber is located; this has the task of keeping the main lip well lubricated. The inner of said three sealing lips is designed so that it skims the surface of the inner race of the bearing during assembly and it has a particular configuration that enables the grease contained in the space between bearing and seal to follow the rubber and to deposit itself towards the outside of the bearing. The dirt guard lip of the seal performs a labyrinth seal with the surface of the inner race of the bearing and makes a sufficiently wide chamber to enable the containment and the expelling of the external polluting agents. The surface of the inner race of the bearing on which the sealing lips slide is toroidally shaped to exploit the centrifugal effect which develops during the rotation of the inner race, to improve the sealing; such shape allows an improvement of the structural resistance of such race.

Claims: A seal for vehicle wheel hub bearings consisting of a rotating inner race and a stationary outer race; the seal comprising: a central body rigidly connected to a metal insert driven onto the outer race of the bearing; an appendix extending from the body of the seal and being compressed onto the outer race of the bearing to form static seal thereon; a dirt guard lip forming labyrinth seal with a toroidally shaped surface of the inner race of the bearing; two sealing lips, defined as outer and main lip, extending from said central body and performing dynamic seal with said toroidally shaped surface of the inner race of the bearing and forming a grease containing chamber with it; said outer lip being oriented towards the outside of the bearing to exploit the centrifugal effect deriving during operation from the rotation of the toroidally shaped surface of the inner race; characterised in that said main lip is also oriented towards the outside of the bearing, like said outer lip, to exploit the same centrifugal effect; a third innermost sealing lip, extending from said central body, being designed so that it skims said toroidally shaped surface during operation to enable the grease contained in the space between the bearing and the seal to flow towards the outside of the bearing. A seal according to claim 1, characterised in that said outer lip is lengthened and flexible to allow sealing against said toroidally shaped surface in case of misalignment of the bearing.

Inventors: COLANZI FRANCO, VIGNOTTO ANGELO, COLANZI, FRANCO, VIGNOTTO, ANGELO
Applicants: RIV OFFICINE DI VILLAR PEROSA, RIV-SKF OFFICINE DI VILLAR PEROSA S.P.A
Application year: 1988
Main classification: F16C33
IPC codes: F16J15, F16C33, F16C19