Rotary shafts – gudgeons – housings – and flexible couplings for ro – Coupling accommodates drive between members having... – Tripod coupling
Reexamination Certificate
1999-05-04
2001-06-26
Browne, Lynne H. (Department: 3629)
Rotary shafts, gudgeons, housings, and flexible couplings for ro
Coupling accommodates drive between members having...
Tripod coupling
C464S124000, C464S905000
Reexamination Certificate
active
06251019
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a constant velocity plunging joint generally comprising an outer joint part having a cylindrical hollow chamber with an aperture at one end, which cylindrical hollow chamber, at its other end, is closed by a base and in which there are formed uniformly circumferentially distributed, longitudinally extending tracks; an inner joint part which is positioned centrally in the cylindrical hollow chamber of the outer joint part so as to be angularly movable and longitudinally displaceable; and torque transmitting elements which, in the direction of rotation, are form-fittingly connected to the inner joint part and which, in the direction of rotation, engage the tracks of the outer joint part form-fittingly so as to roll therein in the longitudinal direction.
Joints of the above described type are used by the joint manufacturers to complete a driveshaft comprising a shaft shank and two joints adjoining same, with the joints being filled with grease and being sealed by convoluted boots relative to the shaft shank. The first joint is a plunging joint of the species described and the second joint usually constitutes a fixed joint. The finished driveshafts are delivered to the vehicle manufacturer, with attaching journals at the plunging joint being inserted into a differential drive and secured therein, while, subsequently, attaching parts of the fixed joint are connected to the wheel hubs.
As these operations cannot take place simultaneously, i.e. first the differential drive with the connected plunging joint is mounted on the vehicle, while the fixed joint cannot be connected to the wheel hubs until later, there arises a situation in the course of the assembly of the vehicle wherein only the plunging joint is mounted while the angled driveshaft with the fixed joint is in a condition where it is freely and oscilatingly suspended. In spite of the relative sluggishness of the plunging joint, which is filled with grease and not yet run in, the weight of the suspended driveshaft with fixed joint may cause the plunging joint to become axially extended until it is finally disconnected inside the convoluted boot. Thereafter, the inner part of the plunging joint cannot be re-introduced into the outer part of the plunging joint until after the removal of the convoluted boot, i.e. the driveshaft has have to be removed and returned to the manufacturer.
Constant velocity joints of a similar type, but comprising a continuous cylindrical hollow chamber which is open at both ends, are already known to be provided with caulkings on the end face at one of the open ends of the outer joint part, these caulkings form raised portions which reduce the free cross-section of the tracks. In accordance with their function, in the form of an anti-dismantling means, they form an insurmountable obstacle to passage of the assembly consisting of the inner joint part and torque transmitting elements through the end face where they are located.
However, in such assemblies it is possible to axially introduce the assembly consisting of the inner joint part and torque transmitting elements from the other open end of the outer joint part, which end retains the free undeformed inner cross-section, i.e., no caulkings, with this open end being closed only subsequently by a cover or flanges which are bolted on or welded on.
It is obvious that with joints of the species of the initially mentioned type with a hollow chamber which is closed at one end by a base, it is not possible to provide caulkings of the type described above in the course of the production of the outer joint part. Therefore, such joints have so far been provided with additional securing elements in the form of sheet metal caps which are rolled into the outer joint part or pressed on to the outer joint part and which, after the assembly consisting of the inner joint part and torque transmitting elements has been axially introduced into the outer joint part, have to be secured to the latter, thus requiring a complicated production measure to be carried out on the partially assembled joint. When, at a later stage, the joint has to be dismantled for maintenance purposes, destruction of the securing elements is unavoidable.
It is therefore the object of the invention to provide plunging joints which are provided with simpler means for preventing unintentional dismantling.
SUMMARY OF THE INVENTION
In accordance with the invention, the objective is achieved in that, at the open end of the outer joint part, the end face is provided with caulkings which form raised portions reducing the free inner cross-section of the cylindrical hollow chamber; that the assembly consisting of the inner joint part and the torque transmitting elements can be introduced through the aperture into the hollow chamber while deforming the raised portions; and that the raised portions apply an axial holding force to the assembly consisting of the inner joint part and of the torque transmitting balls, which axial holding force effectively acts against any self-acting dismantling. Caulkings designed according to the present invention thus permit the assembly consisting of the inner joint part and torque transmitting elements to be assembled in a damage-free way through the outer joint part aperture, which is narrowed by caulkings, with the assembly undergoing only permissible elastic deformation. In an advantageous embodiment, the inventive design of the raised portions also permits subsequent dismantling of the joint for the purpose of maintaining the joint or replacing a convoluted boot in a non-destructive way.
According to a first embodiment, the raised portions are formed of a permanently hardened material and are elastically and plastically deformed when the assembly consisting of the outer joint part and the torque transmitting elements is first introduced. Said embodiment is advantageous in that when the joint is first assembled it is calibrated, so that independently of the tolerances of the respective inner joint part, it is possible to set a substantially fixed, permanent holding force. Initially, the caulkings can be less accurate, so that during the first introduction stage, a certain amount of plastic deformation takes place. The subsequent elastic return of the material determines the holding forces.
According to a second embodiment it is proposed that the raised portions, after having been formed by the caulkings, are hardened and are deformed only elastically when the assembly consisting of the inner joint part and the torque transmitting elements is first introduced. Only non-destructive elastic deformation takes place at the raised portions and at the assembly. The caulkings, prior to being hardened, have to be produced relatively accurately. Optionally, a chip-forming machining operation can take place after the hardening stage, and again, optionally, the caulking operation could, initially, be followed by a plastic deformation operation carried out by a gauge, whereafter the harding operation would take place.
The type of caulkings and the subsequently obtained raised portions largely depend on the track shape. The raised portions are preferably positioned inside the cross-sections of the tracks and especially in the running faces of same, so that they co-operate directly with rolling members. In a preferred embodiment, one single raised portion of an approximately uniform height is produced at the end of each track, or several individual raised portions of identical heights are produced at the end of each track.
According to a first embodiment, it is proposed that the joint is a tripode joint wherein the tracks constitute recesses with two opposed running faces and wherein the torque transmitting elements are tripode rollers supported on tripode arms of the inner joint part, and that, at least on one running face of each recess, there is provided a caulking. This embodiment includes prior art tripode joint designs which will not be explained in greater detail here.
According to a second embodiment it is proposed that th
Hofmann Norbert
Ricks Michael
Browne Lynne H.
GKN Lobro GmbH
Thompson Kenneth
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