Patent Application
20060170165
This application is based on German Patent Application 10 2005 004 323.2 filed Jan. 31, 2005, upon which priority is claimed.
1. Field of the Invention
The invention relates to a sealing element, and to a drive unit containing a sealing element, having a radial shaft sealing ring.
2. Description of the Prior Art
U.S. Pat. No. 4,015,883 discloses a sealing element which is located between an outer and an inner ring of a ball bearing, in order to seal off the roller bodies of the bearing from the environment. The sealing element is embodied as a radial shaft sealing ring, which is braced by an outer radial sealing face on the outer bearing ring, and rests with a diametrically opposed inner radial sealing lip on the inner bearing part, such as a rotatable shaft. For reinforcement, the sealing element has a support ring, which is disposed inside the sealing material. The sealing element also has a spring ring, which presses the inner sealing lip radially against the inner bearing ring. A sealing element of this kind is suitable for radial sealing of two cylindrical jacket faces rotatable counter to one another. However, with such a sealing element, axial sealing between two axially adjacent components cannot be achieved.
The sealing element of the invention, and a drive unit having such a sealing element, have the advantage that because of the integral forming of an axial sealing ring onto the radial shaft sealing ring, a radial dynamic sealing along with an axial static sealing can be simultaneously attained by a single sealing element. As a result, the use of a plurality of separate sealing rings is dispensed with, as are the assembly steps for disposing the various sealing elements. Therefore, because of the reduction in the number of components, both the tool costs for producing them and the costs of assembling and installing them are saved.
Advantageous refinements of the devices are possible. Especially simply, the axially sealing ring element can be integrally formed onto the radial shaft sealing ring with an encompassing connecting strip, since as a result the axial sealing ring is fixed, reliably and exactly centered relative to the radial shaft sealing ring. A connecting strip of this kind is also especially simple, from a process standpoint, to make as part of a one-piece sealing body.
If the axial sealing ring has a larger diameter than the outer diameter of the radial shaft sealing ring, then with this sealing element, in addition to the dynamic radial sealing of an inner rotatable body relative to an outer component, this component can also be reliably sealed off axially from a further axially adjacent component. The radial sealing action of the radial shaft sealing ring is affected only insignificantly, if at all, by the axial contact force of the further component.
Depending on the specific embodiment and use of the two axially adjacent components, the axial sealing ring has a circular, oval, or X-shaped or Y-shaped or double-Y-shaped profile, which is joined in each case to the radial shaft sealing ring via the connecting strip. The axial sealing ring is thus embodied as a simple O-ring, whose cross section is modified to suit the component geometry.
In a further version, one or more sealing barriers are integrally formed onto the axial sealing ring and seal off the two axially disposed flange components from the environment.
It is advantageous to dispose a support body in the interior of the radial shaft sealing ring, which body is preferably embodied as a cup-shaped reinforcement ring, because the dimensional stability—and hence the contact—of the shaft sealing ring with the faces to be sealed off are thus improved.
The sealing element may be made especially favorably as an injection-molded part, in which the outer axially sealing ring is embodied integrally with the sealing body, which forms the outer radial sealing face of the radial sealing ring. It is especially advantageous if the reinforcement ring is spray-coated, as an inlay part, with a single elastic sheathing which simultaneously forms the axial sealing ring.
So that the inner sealing lip can be pressed reliably against the rotary body, a spring ring which contracts is disposed inside the radial shaft sealing ring, thus creating a spring-reinforced sealing lip. This spring can be placed inside the sealing body before the sealing element is installed, so that the sealing element of the invention can be installed as a single component.
To attain a reliable sealing action, the reinforcement ring is made of metal, preferably sheet steel, and the sealing body is preferably made of an HNBR or EPDM rubber or silicone.
The drive unit of the invention has the advantage that because of the use of the sealing element with the combination of the radial and the axial sealing, the number of components and hence the expense of assembly and installation are reduced.
In a gearbox, not only is a rotatable driven wheel reliably sealed off but an axial seal for binding to a customer-specific gear interface reliably is also created.
Because of the one-piece embodiment of the O-ring or of the axial sealing ring with the radial sealing ring, the axial sealing ring is reliably positioned and fixed upon the installation of the radial sealing ring in the housing of the drive unit. Thus this drive unit, with this kind of open gear interface, can already be shipped to the customer with completely installed seals, and the customer can without providing further axial sealing rings connect this drive unit directly to the customer-specific gear interface. This kind of captive, positionally precise disposition of the O-ring on the mounting face of the drive unit represents an enormous advantage for mounting the customer-specific gear interface.
The invention will be better understood and further objects and advantages thereof will become more apparent from the ensuing detailed description of preferred embodiments, taken in conjunction with the drawings, in which:
In
The axial sealing ring 14 is integrally formed onto the radial shaft sealing ring 12 via a encompassing connecting strip 50. In the exemplary embodiment, the axial sealing ring 14 is embodied integrally with the sheathing 42 of the radial shaft sealing ring 12. As a result, the U-shaped radial shaft sealing ring 12 can be made together with the axial sealing ring 14 as an injection-molded part in a single process in a single injection-molding tool. The annular spring element 44 is then placed afterward in the U-shaped profile 36 of the radial shaft sealing ring 12. As the sheathing 42 for the radial shaft sealing ring 12 and for the axial sealing ring 18, an NBR or EPDM soft rubber, or some other elastomer, is preferably used as industrial rubber material. The encompassing connecting strip 50 has at least one radial component, so that the axial sealing ring 14 is located with a middle diameter 52 radially outside the outer diameter 54 of the outer sealing face 16. The axial sealing ring 14 has a cross section 56, which in the exemplary embodiment of
In a further exemplary embodiment, as shown in the bottom half of
The sealing element 10 in
In
It should be noted that in terms of the exemplary embodiments shown in the drawings, manifold combinations of the various characteristics with one another are possible. For instance, the specific design of the radial shaft sealing ring 12 and of the axial sealing ring 14 can be adapted to the intended use. One skilled in the art is familiar with various versions of radial sealing rings 12: with or without an annular spring 44, with or without a support ring 40, and acting unilaterally or on both sides in terms of its pressure load. The specific embodiment of the sealing lip 26 with the sealing edge 28, and the outer sealing face 16 with the structuring 20, can also be embodied arbitrarily. What is decisive for the invention is that the axial sealing ring 14 is joined to the radial shaft sealing ring 12, so that simultaneously with the dynamic radial sealing, an axial sealing for a further component 70 is furnished. The specific embodiment and production of the connecting strip 50 can also vary; for instance, the connecting strip 50 need not be embodied as extending all the way around. The length, thickness and orientation of the connecting strip 50 likewise depends on the precise sealing geometry of the components 22, 30, 70 to be sealed off and can be adapted accordingly. The axial sealing ring 14 is embodied as an O-ring extending all the way around, and its cross section 56, 57 or sealing contour with its sealing faces 62, 64 and sealing barriers 58 can also be varied arbitrarily. Preferably, the sealing element 10 of the invention is used in the electric motor gear and drive unit 80, which has a gear interface with a customer-specific gear component 71. For instance, a drive unit 80 of this kind is used in a motor vehicle for adjusting moving parts, and particularly for an automatic transmission or a differential gear.
The foregoing relates to preferred exemplary embodiments of the invention, it being understood that other variants and embodiments thereof are possible within the spirit and scope of the invention, the latter being defined by the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2005 004 323.2 | Jan 2005 | DE | national |
