Seal for a joint or juncture – Seal between relatively movable parts – Diverse and distinct dynamic seals
Reexamination Certificate
1999-08-13
2001-08-14
Brittain, James R. (Department: 3626)
Seal for a joint or juncture
Seal between relatively movable parts
Diverse and distinct dynamic seals
C277S352000, C277S361000, C277S374000, C277S402000, C277S407000
Reexamination Certificate
active
06273428
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an annular seal assembly of a type intended for mounting between the drive shaft of a vehicle with a diesel or petrol engine and the crankcase and/or the oil sump in order to retain the oil.
BACKGROUND OF THE INVENTION
In the prior art, the same type of seal assembly has been used for a long time for this application, that is one formed by a radial V-shaped spring-loaded lip, which cooperates slidably or directly with the drive shaft or, in more sophisticated seal assemblies, with a radial surface of a sealing screen keyed on the drive shaft. In any case, the seal is exclusively radial and the sealing force exerted by the lip is in direct proportion to the load of the spring and to the state of wear of the lip.
Seal assemblies of the type described have the disadvantage of exerting a progressively deteriorating sealing action as the lip becomes worm This limits the life of this type of seal which is, in addition, sensitive to external contamination and which is therefore protected by an additional seal assembly, known as a dust shield. It is clear that this makes running costs relatively high.
SUMMARY OF THE INVENTION
The object of the invention is to provide a seal assembly free of the disadvantages described and providing a highly effective seal, which is able substantially to maintain this high efficiency even as the lip becomes progressively worn, and which is both inexpensive and compact.
This object is achieved according to the invention by providing a seal assembly which can be fitted between two relatively rotatable members, which includes a first annular screen, securely fixed to one of the said members and having a seal member made of an elastomeric material, and a sliding surface, securely fixed to a second of the said members, the said first screen comprising in turn a sleeve portion to be fitted onto the said first member and a radial flange portion arranged substantially perpendicular to the sleeve portion and substantially facing the said sliding surface; the said sealing member being carried by the said first screen at a perimetral edge of the flange portion thereof and including a first annular lip, which extends axially from the flange portion, from its root portion, towards the said sliding surface; characterised in that the said first lip includes an enlarged end portion opposite, and radially offset with respect to, the root portion, delimited by a circumferential rim and by an annular sealing projection with a V-shaped radial section and an axially oriented sealing edge; the said circumferential rim having a radial annular seat for a resilient, circumferential retaining member, operable to exert a predetermined radial stress on the first lip, the V-shaped projection being arranged beside the seat for the resilient member, with the sealing edge towards the sliding surface carried by the said second member, with which it cooperates slidably in an axial direction.
In particular, the enlarged portion of the first lip is connected to the root portion by an annular portion formed so as to constitute a resilient hinge with its centre of rotation arranged along a line passing through the said sealing edge and forming an angle (&ggr;) of between 20° and 60° with a radial plane parallel to the said sliding surface.
In practice, the seal assembly of the invention provides an entirely similar seal to that obtained with prior art seal assemblies (where it is also possible to identify an angle &ggr;, which is one of the parameters of the seal), with the difference, however, that the sealing action is provided axially rather than radially and with the further difference that the seat of the spring which stabilizes the sealing load is rotated through 90° with respect to the reference plane for measurement of the angle &ggr;.
In this way, (as can be demonstrated by a series of mathematical calculations) the load imparted by the spring becomes independent of the wearing of the sealing edge, making it possible to manufacture more effective seal assemblies, which maintain the same sealing action for the entire life of the sealing lip, independently of its state of wear.
Further characteristics and advantages of the present invention will become apparent from the following description of a non-limitative embodiment, with reference to the appended drawing, which illustrates part of a radially sectioned view of a seal assembly according to the invention, the missing portion being symmetrical to that illustrated with respect to an axis of symmetry A.
REFERENCES:
patent: 3822890 (1974-07-01), Bourgeois
patent: 3871669 (1975-03-01), Repella
patent: 4460184 (1984-07-01), Colanzi et al.
patent: 4596394 (1986-06-01), Schmitt
patent: 4770425 (1988-09-01), Colanzi et al.
patent: 4799808 (1989-01-01), Otto
patent: 4928979 (1990-05-01), Nagasawa
patent: 4986552 (1991-01-01), Anzue et al.
patent: 5042822 (1991-08-01), Dreschmann et al.
patent: 5348312 (1994-09-01), Johnston
patent: 5676383 (1997-10-01), Chandler
patent: 5967527 (1999-10-01), Fabro et al.
patent: 5975534 (1999-11-01), Tajima et al.
patent: 3739513 (1989-06-01), None
Beres John L.
Brittain James R.
Burns Doane Swecker & Mathis L.L.P.
RFT S.p.A.
LandOfFree
Annular seal assembly, in particular for the drive shaft of... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Annular seal assembly, in particular for the drive shaft of..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Annular seal assembly, in particular for the drive shaft of... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2435579