Rotary shafts – gudgeons – housings – and flexible couplings for ro – Coupling accommodates drive between members having... – Coupling transmits torque via radially spaced ball
Reexamination Certificate
1999-07-09
2001-08-07
Browne, Lynne H. (Department: 3629)
Rotary shafts, gudgeons, housings, and flexible couplings for ro
Coupling accommodates drive between members having...
Coupling transmits torque via radially spaced ball
C464S906000
Reexamination Certificate
active
06270419
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a constant velocity fixed joint.
DE 40 31 820 C2 describes a constant velocity fixed joint whose outer part comprises a first open end and a second open end. It comprises a cavity which is centered on the longitudinal outer part axis and which is open towards both open ends. Furthermore, in its inner face delimiting its cavity, the outer part comprises two types of outer running grooves which are arranged in a regular sequence around the longitudinal outer part axis in meridian planes relative to the latter. The first outer running grooves start from the first open end and extend towards the second open end. The second outer running grooves start from the second open end and extend towards the first open end. All outer running grooves extend in a curve-like and undercut-free way from the open end from which they start.
In the cavity of the outer part, there s arranged an inner part. The inner part comprises a longitudinal inner part axis and a spherical outer face which is provided with first and second inner running grooves which are arranged opposite the first and second outer running grooves and extend in meridian planes relative to the longitudinal inner part axis. The first inner running grooves are arranged opposite the first outer running grooves in such a way that they form pairs, with the first inner running grooves starting from the first open end and extending towards the second open end in a curve-like and undercut-free way.
The second inner running grooves are arranged opposite the second outer running grooves and form pairs therewith, with the second inner running grooves starting from the second open end and extending towards the first open end in a curve-like and undercut-free way.
Between the inner face of the outer part and the spherical outer face of the inner part there is arranged a cage whose spherical outer face comprises play relative to the inner face of the outer part. The cage is provided with a cylindrical bore which is held with play relative to the spherical outer face of the inner part. The cage is provided with radial apertures which are distributed in accordance with the pairs of inner running grooves and outer running grooves. The apertures form windows which guide the balls between the lateral guiding faces.
For torque transmitting purposes, the balls engage between the outer part and inner part into the outer running grooves and inner running grooves forming pairs. The centers of all balls are held in a plane which contains the window centers between the lateral guiding faces. The cage is centered entirely by the balls.
The above-described design is disadvantageous in the case of constant velocity joints rotating at high speeds such as they occur, for example, in the propeller shaft for transmitting a rotational movement in passenger cars from the front drive unit of same to the rear axle drive for rear wheel drive vehicles. In particular, vibrations occur to the displacement of the center of gravity of the cage, as a result of which a centrifugal force is generated.
DE 40 42 390 C2 proposes a constant velocity fixed joint whose design corresponds to that of the joint described in DE 40 31 820 C2. However, the cage is divided; it comprises a spherical inner face and lugs in the region of the lateral guiding faces, with said lugs increasing the size of the lateral guiding faces outwardly.
SUMMARY OF THE INVENTION
It is an object of the invention to provide an improved constant velocity fixed joint.
The foregoing and other objects are achieved by a constant velocity fixed joint having an outer part comprising a first open end and a second open end, a longitudinal outer part axis, a cavity which is centered on the longitudinal outer part axis and which is open towards both ends, and first outer running grooves and second outer running grooves in its inner face delimiting the cavity. The first outer running grooves and the second outer running grooves are arranged in a regular sequence around the longitudinal outer part axis in planes which are distributed around the longitudinal outer part axis and contain same. Further, the first outer running grooves, while starting from the first open end, extend towards the second open end, and the second outer running grooves, while starting from the second open end, extend towards the first open end. Both the first and second outer running grooves extend in a curve-like and undercut-free way.
The constant velocity fixed joint further includes an inner part which is arranged in the cavity of the outer part and which comprises a longitudinal inner part axis, a spherical outer face and first inner running grooves and second inner running grooves which are arranged in the spherical outer face and extend in planes which are distributed around the longitudinal inner part axis and contain same. Each of the first inner running grooves are arranged opposite a first outer running groove, and, while starting from the first open end, extend towards the second open end in a curve-like and undercut-free way. Each of the second inner running grooves are arranged opposite a second outer running groove and, while starting from the second open end, extend towards the first open end in a curve-like and undercut-free way.
The constant velocity joint also includes a cage which comprises a continuous inner cage face centered on the longitudinal cage axis and comprises hollow spherical portions, an outer face delimited at least partially by a sphere in the form of an envelope sphere, as well as windows with lateral guiding faces. The windows extend radially in accordance with the pairs of inner running grooves and outer running grooves. The cage, by means of the hollow spherical portions of its inner cage face, is guided on the spherical outer face of the inner part. The outer face of the cage is arranged at a distance from the inner face of the outer part and comprises lugs which increase the size of the two lateral guiding faces and project beyond the outer face. All windows comprise a common central plane extending centrally between the lateral guiding faces and have balls which are each received by opposed inner running grooves and outer running grooves. The balls are guided in the windows of the cage between the lateral guiding faces.
Because the pairs of running grooves extend in opposite directions, it is possible to achieve advantageous centering conditions which are improved even further because of the way in which the cage is centered relative to the inner part. Even at large articulation angles up to approximately 30° and at high rotational speeds, such constant velocity fixed joints ensure smooth running conditions. In addition, they have a long service life. Furthermore, the lugs ensure advantageous guiding conditions for the balls, even at high articulation angles.
In a further embodiment, to achieve advantageous production and assembly conditions, it is proposed that, apart from the projecting outer lugs, the outer face of the cage, at least towards the axial ends, is shaped spherically.
Assembly is particularly easy if the region between the spherical end portions is cylindrical. In this way, it is possible to achieve a kind of plug-in assembly. In other words, the balls of all tracks opening towards one end can be pre-fitted and then introduced together with the cage into the outer part. Subsequently, the balls of the tracks extending in the opposite direction are introduced from the outside through over-articulating. An advantageous design is achieved if the outer part is produced by non-chip forming, starting from a plate metal sheet or a tube, so that the outer part comprises a uniform wall thickness along its length and its circumference. This method requires low forming forces, thus permitting the production of tracks with a high degree of repeat accuracy. Again, this results in smooth running conditions because track shapes deviating from the ideal track are largely eliminated.
For connecting the outer part to a driving or driven component, it is propo
Browne Lynne H.
GKN Lobro GmbH
Thompson Kenn
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