Seal for a joint or juncture – Seal between fixed parts or static contact against... – Contact seal for other than internal combustion engine – or...
Reexamination Certificate
1998-08-17
2001-05-29
Knight, Anthony (Department: 3626)
Seal for a joint or juncture
Seal between fixed parts or static contact against...
Contact seal for other than internal combustion engine, or...
C277S637000, C277S641000, C464S173000
Reexamination Certificate
active
06237920
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a sealing assembly for a constant velocity universal joint. The joint includes an inner joint part which is connected to a driveshaft and an outer joint part which is sealed relative to the driveshaft by a convoluted boot and which has a flange face, directly contacted by a counter flange face of a counter flange in an annular contact region. An annular gap is formed radially inside the contact region between the flange face and the counter flange face. A sealing cover is provided at the outer joint part, which sealing cover, with an edge region of same, is located in the annular gap.
Constant velocity universal joints in the present sense may be constant velocity universal ball joints, tripode joints or similar joints serving the transmission of torque. Constant velocity universal joints of these types are normally marketed as integral parts of complete driveshafts consisting of a shaft shank and two joints mounted at the ends of the shaft shank. The joints are provided with a grease filling. The respective outer joint parts are ready to be mounted on counter flanges and are sealed relative to the shaft shank by convoluted boots. At their outer flange faces they are sealed by plate metal covers which do not only prevent the grease filling from leaving the joint during transport and assembly, and also in operation when the grease filling becomes highly liquid due to an increase in temperature and is under the influence of a centrifugal force. This objective cannot be achieved by the flange faces of the outer joint parts and the counter flange faces of the counter flanges, which flange faces and counter flange faces contact one another, because the latter are forged faces and as such they are produced too inaccurately.
U.S. Pat. No. 4,436,310 describes a sealing assembly for a constant velocity universal joint of this type wherein the constant velocity universal joint is provided in the form of a tripode joint which, in consequence, has a flange face which is not rotationally symmetric. To avoid any positional errors of the sealing cover relative to the outer joint part, there are provided engaging means in the flange face and at the sealing cover. The sealing cover is annularly clamped between the flange face of the outer joint part and the counter flange face of the counter flange; it is thus force-lockingly connected to the two parts and, in consequence, is included in the torque flow of the driveshaft after the latter has been mounted. This means that special requirements have to be met by the material properties and the production quality of the three parts.
It is therefore the object of the present invention to provide a sealing assembly of this type which can be produced more cost-effectively and with greater tolerances, but which, at the same time, ensures a reliable sealing function under all operating conditions.
SUMMARY OF THE INVENTION
The objective is achieved in that the flange face directly contacts the counter flange face in an annular contact region, with an annular gap being formed radially inside the contact region between the flange face and the counter flange face. The sealing cover is located in the annular gap with its edge region. The sealing cover is connected to the outer joint part by means of an adhesive layer which consists of a sealing agent applied so as to have a sealing effect relative to the flange face and relative to the sealing cover. The sealing cover is at least partially displaced into the annular gap by the counter flange. This occurs while the outer joint part and the counter flange are braced together with the sealing cover being maintained under permanent pretension. These means permit a cost-effective connection between the sealing cover and the outer joint part, which connection can be established easily and quickly, and satisfactorily meets the requirements of a reliable seal which is effective until the driveshaft is fully assembled, i.e. until the outer joint part is connected to the counter flange. Those versed in the art have access to adhesives which act as sealing agents and are characterized by adequate holding forces which withstand the loads expected during transport and assembly. However, no great demands are made regarding the accuracy of the glued connection which, relative to the design of the flange and of the sealing cover, merely has to ensure that the sealing cover projects beyond a plane which is defined by the counter flange face after the outer joint part and the counter flange have been tensioned relative to one another. In this way, the sealing cover is partially displaced by the counter flange face into the annular gap, while a permanent pretension is maintained between the sealing cover and the counter flange face, which permanent pretension is added to the previously effective adhesion forces. As a result of this glued connection secured in this way, the driveshaft is adequately sealed under operating conditions which, at speeds of 9000 r.p.m., are characterized by increased operating temperatures combined with a correspondingly high internal pressure and extreme mechanical loads in the form of vibrations and impacts. The sealing cover radially ending in the annular gap is kept out of the flow of force between the flange face and counter flange face and out of the torque flow between the outer joint part and the counter flange. This means that the sealing cover can be produced from inferior materials and with a relatively reduced production accuracy. In particular, the sealing cover can consist of plastics and can be produced by injection molding or deep-drawing, or it can consist of rubber which, if necessary, is reinforced by fabric or fibers. The sealing cover can also consist of plate metal which can be plastic-coated to provide protection against corrosion.
In order to achieve the partial displacement or deformation of the sealing cover into the annular gap during the assembly of the outer joint part and the counter flange, different embodiments regarding the combination of sealing cover and adhesive layer are possible.
According to a first embodiment, the sealing cover is displaced into the annular gap, with the adhesive layer being elastically and/or plastically deformed. This requires a permanently elastic adhesive which, while having an adequate thickness, becomes a structural and functional element.
According to a second embodiment it is proposed that the sealing cover is displaced into the annular gap, with the edge region of same being elastically and/or plastically deformed.
By plastically deforming part of the sealing cover it becomes possible in a particularly advantageous way to compensate for production inaccuracies at the counter flange face and thus to produce the counter flange face in a less refined quality. In consequence, the counter flange can be a forging with an unmachined counter flange face.
In this embodiment, it is possible for the layer of adhesive to be relatively unresilient and thin and to achieve the secure contact between the counter flange and the sealing cover under pretension by elastically deforming the sealing cover, especially in an annular region. In particular, it is possible to provide the edge of the sealing cover with easily deformable formations or to shape it in such a way that it is conical in a plate-spring-like way.
In all the above-mentioned embodiments it is possible that either a continuous edge of the sealing cover is in contact with the counter flange face or that circumferentially interrupted nap or rib regions of the sealing cover are in contact with the counter flange face. In the latter case, it is possible to achieve greater axial deformation distances at relatively lower forces.
REFERENCES:
patent: 4436310 (1984-03-01), Sawabe et al.
patent: 5678933 (1997-10-01), Ouchi et al.
patent: 5938208 (1999-08-01), Yoshida et al.
patent: 5984039 (1999-11-01), Mayr
patent: 29 21 292 A1 (1979-11-01), None
patent: 32 10 389 A1 (1983-04-01), None
patent: 43 09 652 A1 (1993-03-01), None
patent: 1 078 563
Löbert Amrei
Nicolai Michael
GKN Lobro GmbH
Knight Anthony
Peavey Enoch E
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