GB2192953A

GB2192953A - A bearing with an improved sealing assembly

Info

Publication number: GB2192953A
Application number: GB08715234A
Authority: GB
Inventors: Gabriele Bermond; Angelo Vignotto
Original assignee: RIV SKF Officine di Villar Perosa SpA; RIV Officine di Villar Perosa SpA
Current assignee: SKF Industrie SpA
Priority date: 1986-07-11
Filing date: 1987-06-29
Publication date: 1988-01-27
Anticipated expiration: 2007-06-29
Also published as: IT8653616V0; IT208051Z2; GB8715234D0; FR2601424B3; FR2601424A3; DE3721819A1; GB2192953B

Description

GB2192953A 1 SPECIFICATION in a single operation together with the respec

tive rolling track of the ring.

A bearing with an improved sealing as- For better understanding of the present in sembly vention a preferred embodiment is now de 70 scribed purely by way of non-limitative The present invention relates to a rolling ele- example, with reference to the attached draw ment bearing with an improved sealing as- ings in which:

sembly of the sliding lip type. Figure 1 is a partially sectioned view of a Rolling element bearings which utilise sealing bearing; and assemblies of the above indicated type have 75 Figure 2 is a section on an enlarged scale of two main disadvantages, the first of which lies a detail of the bearing of Fig. 1.

in the fact that the efficiency of the sealing As illustrated in Fig. 1 a rolling element assembly depends on the precision of as- bearing is generally indicated with the refer sembly thereof in the seat formed between ence numeral 1, comprising an inner ring 2, an the rings of the bearing and on the degree of 80 outer ring 3 and a plurality of rolling bodies 4 constructional precision of this seat. Since the interposed between the rings 2 and 3 in an sea[ is formed by the cooperation between annular space 5 lying between them. The one or more sliding lips and the surfaces of bodies 4 roll between respective tracks 6 the said seat it is evident that if the assembly formed, respectively, on the outer surface of is not correct the interference between the 85 the inner ring 2 and on the inner surface of sliding lips and the surfaces of the seat will the outer ring 3, in such a way as to permit not be of the designed value with the conse- the relative rotation of the rings 2-and 3. The quence that a reduction in the efficiency or an annular space 5 is closed to the exterior in a unwanted increase in the friction of the screen fluid tight manner on both sides by respective itself will occur. The second disadvantage lies 90 sealing assemblies 7, each snap fitted into a in the fact that since the seat of the sealing seat 8 formed on the inner surface of the assembly is of complex shape the production outer ring 3. The fixing of the sealing as of this involves particular working operations sembly 7 to this latter is of known type and, and is therefore onerous. for example, provides for the snap housing The object of the present invention is that 95 into the seat of an elastic annular lip extending of providing a bearing wth an improved seal- from the sealing assembly 7 and, in more de ing assembly which will be free from the tail, from an elastomeric sealing element 11 stated disadvantages and, therefore, which carried by an annular substantially rigid sup will have a sealing assembly the efficiency and port and reinforcement element 12 preferably operating friction of which will be independent 100 made of metal or plastics material. The ele- of the precision of assembly thereof in its ments 11 and 12 constitute a single body working seat, and of the constructional preci- because they are intimately joined together by sion with which this seat is formed; it is de- co-moulding or by means of glueing in a vul sired, moreover, that this latter should be sim- canisation stage depending on the material ple to form. 105 utilised to form the element 12. Radially and According to the present invention there is axially from an annular root portion 13 of the provided a bearing with an improved sealing element 11 projects a radially inner deforma assembly, ofthe type comprising an inner ble annular sealing lip 14.

ring, an outer ring and a plurality of rolling As illustrated in Fig. 2, the lip 14 is inte- bodies interposed between the said rings in 110 grally formed in one piece with the element an annular space lying between them rolling in 11 and is able to cooperate with respective respective tracks in such a way as to permit sealing surfaces 15 and 16 of an annular seal the relative rotation of the said rings, charac- ing seat 17 formed on the outer surface of terised by the fact that the said sealing as- the inner ring 2. In particular, the seat 17 is sembly is able to ensure the fluid light closure 115 formed in such a way that it does not present of the said space and comprises a substan- undercut or convoluted outlines so that it can tially rigid support element and an annular be made, according to the invention, in a sin elastomeric sealing element provided with an gle operation together with the associated inner radial annular lip extending radially and track 7, for example, with a common grinding axially and projecting from an annular root 120 operation on the outer surface of the ring 2; portion of the said elastomeric element; the the surface 15 is substantially coaxial with the said lip having a radial part of substantially V- axis of the ring 2, whilst the surface 16 is shape, the vertex of which is disposed sub- disposed inclined almost orthogonally to the stantially parallel to the axis of the said eleas- surface 15. The lip 14 is shaped in such a tomeric when the lip is undeformed, the said 125 way as to be able to exert on the seat 17 a lip including a first and a second part defining double sealing action both in a radial direction the sides of the V which can cooperate with and in an axial direction thereof, which differs respective sliding surfaces of an annular sealfrom the majority of known sealing assemblies ing seat on one of the said rings of the bear- which achieve the same result require the use ing, formed in such a way as to be obtained 130 of two different separate lips.

2 GB2192953A 2 The lip 14 is shaped in such a way as to face 15. Consequently, in the presence of an define a toroidal bellows element having a ra- assembly error, or an error in the form of the dial part of substantially V-shape, the vertex seat 17, this error can be at least in part of which is disposed at rest, or rather in an compensated by the deformation of the lip 14 undeformed position (indicated in broken outand, in any case, if it also happens that the line in Fig. 2) substantially parallel to the axis corner 23 remains spaced from the surface 16 of the element 11. This toroidal element is there is an interference between the corner 24 composed of two opposite annular conical and the surface 15. Therefore, even if, be parts 21 and 22 defining the sides of the V, cause of assembly errors, or errors of form, joined together at the vertex of the V by 75 the axial seal (corner 23surface 16) were in means of a common part of reduced thickness adequate, there is always formed the radial in such a way as to be pivotally connected seal between the corner 24 and surface 15. It and disposed coaxially one behind the other. is to be noted, moreover, that the free end of Close to the said vertex there is defined on the part 22 is internally bevelled in such a the part 21 a sealing corner 23 cooperable to 80 way as to define a surface which, in the event form a fluid tight seal with the inclined sealing of wear of the corner 24 which internally de surface 16. The free end of the part 22 is limits it, can form a seal with the surface 15 bevelled in such a way as to define a corner against which is pressed by the form of the 24 which can cooperate to form a fluid tight part 22.

seal with the sealing surface 15. The lip 14 85 From what has been described above the therefore has a corner 23 able to cooperate advantages connected with the invention w1l axially by sliding and with interference with be evident, such as, for example, the seal the surface 16 and a corner 24 radially coo- which is formed even in the presence of er perable to slide with interference on the sur- rors in assembly and form, and, for example face 15. The root portion 13 is L-shape in 90 the constructional simplicity of the seat 17. In radial section, having a part 25 extending radi- fact, this latter is produced simultaneously ally and co-planar with the annular inner edge with the track for the rolling bodies. For this of the element 11 and having a part 26 reason, and because of the already described slightly inclined with respect to the axis of the manner of assembly, high precision grinding is element 11 and extending from the part 25 95 not necessary in that a fluid tight seal is towards the space 5 in such a way that the achieved in all cases because of the shape of whole lip 14 has the possibility of flexing. As the lip 14.

illustrated in Fig. 2, the assembly of the lip 14 Finally, it is clear that the bearing 1 de in the seat 17 involves the elastic deformation scribed and illustrated here can have modifica of the lip 14 itself in such a way as to create 100 tions and variations introduced thereto without interference between the corners 23 and 24 by this departing from the protective ambit of and the respective sealing surfaces 16 and the present invention.

15. It is to be noted that when the lip 14 is

Claims

undeformed the vertex of its V is parallel to CLAIMS the axis of the

element 11. The lip 14 is 105 1. A bearing with an improved sealing as shaped in such a way as to allow relative sembly, of the type comprising an inner ring, rotations of the parts 21 and 22 as a result an outer ring and a plurality of rolling bodies of stresses exerted on only one or two. In interposed between the said rings in an annu particular, in the element 11 it is possible to lar space lying between them and roll ' ing in define two elastic hinges or fulcra about which 110 respective tracks so as to permit relative rota- the parts 21 and 22 turn during the deforma- tion of the said rings, characterised by the tion which takes place upon assembly. The fact that the said sealing assembly is able to part 21 turns about the root portion 13 de- ensure the fluid tight closure of the said space forming the part 26 of this in a restricted and comprise a substantially rigid support ele manner as well, whilst the part 22 turns about 115 ment and an elastomeric annular sealing ele the section of reduced thickness where it is ment provided with a radially inner annular lip connected to the part 21. Following a rotation extending radially and axially from an annular of the part 21 in the direction of the arrow root portion of the said elastomeric element; (Fig. 2) about the root portion 13, for example the said lip having a radial section of substan- because of the elastic deformation due to the 120 tially V-shape the vertex of which is disposed interference which is created upon assembly substantially parallel to the axis of the said between the corner 23 and the surface 16, a elastomeric element when the lip is unde rotation in the opposite direction of the part formed, the said lip including first and second 22 about the connection section to the part parts defining the sides of the V which can 21 is caused in such a way that it exerts a 125 cooperate with respective sliding surfaces of contact pressure between the corner 24 and an annular sealing seat formed on one of the the surface 15. It is to be noted that the said rings of the bearing formed in such a diameter of the circumference, calculated way as to be produced in a single operation along the corner 24, is less than the diameter together with the respective rolling track of of the circumference calculated along the sur130 the ring.

3 GB2192953A 3
2. A bearing according to Claim 1, characterised by the fact that the said sliding surfaces comprise a first substantially coaxial to the axis of the said inner ring, and a second 5 inclined and almost orthogonal to the first.
3. A bearing according to Claim 2, characterised by the fact that the said first and second parts of the lip are conical and are connected together at the vertex of the said V close to a first corner able to cooperate by sliding and interference with the said second sliding surface and formed on the first part of the said sealing lip.
4. A bearing according to Claim 2 or Claim 3, characterised by the fact that the free end of the said second part is bevelled in such a way as to define a second corner able to cooperate by sliding and interference with the said first sliding surface.
5. A bearing according to any preceding Claim characterised by the fact that the said root ortion has, in radial section, a substantially L-shape with a first part extending radially and substantially co-planar to the said elastomeric element and a second part extending inwardly of the said space and connected to the said first part of the said lip.
6. A bearing with an improved bearing assembly as described and illustrated with refer- ence to the attached drawings.

Published 1988 at The Patent Office, State House, 66/71 High Holborn, London WC 1 R 4TP. Further copies may be obtained from The Patent Office, Sales Branch, St Mary Cray, Orpington, Kent BR5 3RD. Printed by Burgess & Son (Abingdon) Ltd. Con. 1/87.