Torque transmission assembly

In a torque transmitting assembly including a driven member and a driving member, one having teeth thereon extending parallel to the rotational axis and the other having teeth thereon extending obliquely to the rotational axis, an annular member is interposed which also has teeth which are parallel to the rotational axis and oblique to the rotational axis for engaging with the corresponding teeth of the driving and driven members in order to place them in torque transmitting engagement with each other. The annular member is formed from a deformable metallic material and the obliquely extending teeth extend relative to the parallel teeth at an angle of between 15.degree. and 45.degree..

The present invention relates generally to torque transmitting devices and 
more particularly to a device for transmitting torque between a driving 
part and a driven part. 
In devices of the type to which the present invention relates, the driving 
and driven parts are arranged so as to be at least partially coaxial 
relative to each other. Gear teeth are provided in engaging relationship 
between the parts and a pressure nut and bolt hold the assembly together. 
Generally, the torque transmitting devices to which the present invention 
relates operate to transmit torque from a rotary constant velocity 
universal joint of a driven motor vehicle wheel to the wheel hub upon 
which the wheel is affixed. Usually, one of the two parts is provided with 
circumferentially spaced teeth extending parallel to the axis of rotation 
of the parts and the other part is provided with an extending area in the 
form of a truncated cone, the cylindrical area of which comprises teeth 
which extend at an angle relative to the axis of the two parts whose 
imagined extensions intersect the axis at a point, with provision being 
made, between the two sets of teeth, for a ring whose cross-section is 
approximately triangular and which has a bore and a outer surface forming 
a triangular area which has been provided with teeth which correspond to 
the teeth of the other two parts and against which the nut and bolt 
respectively may be pressed. 
A device of this kind is described in U.S. Pat. No. 4,433,877 wherein, for 
the purpose of transmitting torque from a driving part to a driven part, 
there is recognized the importance of utilizing a ring whose geometric 
configuration is approximately triangular and which, both at its outside 
and inside, has been provided with teeth. The ring to be fixed in the 
axial direction by a nut engages into corresponding teeth which, in turn, 
are arranged at both the driving and driven parts of the torque 
transmitting device. 
Although the concept of using a toothed ring has been proposed, it has been 
found that such a ring does not provide an optimum design because it 
neither permits a centering of the components which are to be connected 
together nor does it ensure tensioning in the axial direction. 
The present invention is therefore directed toward providing a design for a 
toothed ring of the type described which, while having served only for 
torque transmitting purposes, is arranged in such a manner that at the 
same time it may also be used for centering the components as well as for 
producing necessary axial tension. The invention operates to optimize in 
this respect the function of the device and to facilitate assembly and 
production. 
SUMMARY OF THE INVENTION 
Briefly, the present invention may be described as a torque transmitting 
assembly comprising a driven member and a driving member each arranged to 
rotate about an axis of rotation, parallel teeth on one of said driving 
and driven members extending generally parallel to its axis of rotation, 
oblique teeth on the other of said driving and driven members extending 
obliquely relative to its axis of rotation, and an annular member 
interposed in torque transmitting engagement between said driving and 
driven members, said annular member having a generally triangular 
cross-sectional configuration with parallel teeth thereon formed on one 
side thereof for engagement with said parallel teeth on said one of said 
driving and driven members and with oblique teeth thereon on another side 
thereof for engagement with said oblique teeth of said other of said 
driving and driven members, said annular member being formed from 
deformable metallic material with said parallel teeth and said oblique 
teeth extending relative to each other at an angle which is between 
15.degree. and 45.degree.. 
Thus, in accordance with the present invention, the objectives thereof are 
achieved in that the deformable annular member or ring is composed of a 
metallic ring which is elastically and/or plastically deformable and which 
has a cylindrical face carrying outer teeth forming an angle .alpha. of 
approximately 15.degree. to 45.degree., but preferably 30.degree., 
relative to inner teeth arranged so as to be parallel to the axis of 
rotation. 
In accordance with one embodiment of the invention, the outer and inner 
teeth are designed as pointed teeth. 
In accordance with a further feature of the invention, the inner teeth are 
offset relative to the outer teeth in such a manner that the point of a 
tooth of one set of the teeth and the tooth base between two teeth of the 
other set of teeth lie in a common plane. 
A further important feature of the invention involves the face that between 
the inner teeth and the teeth of the corresponding other part, in an 
untensioned condition, there exists a play of approximately 0.05 to 0.2 
mm. 
The invention as proposed thus far is rounded off and completed in that the 
annular member or ring including its teeth is produced by precision 
forming, especially cold forming. 
The various features of novelty which characterize the invention are 
pointed out with particularity in the claims annexed to and forming a part 
of this disclosure. For a better understanding of the invention, its 
operating advantages and specific objects attained by its use, reference 
should be had to the accompanying drawings and descriptive matter in which 
there are illustrated and described preferred embodiments of the 
invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring now to the drawings, and more particularly to FIGS. 1-4 wherein 
there is depicted a preferred embodiment of the invention, there is shown 
in FIG. 1 a wheel bearing assembly comprising a rotary constant velocity 
universal joint for a motor vehicle which consists essentially of a wheel 
hub 1, the end of which has been provided with a flange 2 which serves to 
mount a wheel (not shown). The wheel hub 1 has a cylindrical projection 3 
which accommodates therein an inner bearing ring 4 of a roller bearing. 
The inner bearing ring 4 is formed with grooves wherein rolling members 5 
are engaged, and an outer bearing ring 6 is also configured to be engaged 
with the rolling members 5. 
A carrier 7 for the wheel bearing assembly operates to ensure mounting of 
the assembly at a motor vehicle location (not illustrated). 
The cylindrical projection 3 defines an inner bore 8 wherein there is 
contained a journal 9 of an outer joint member 10 of a rotary constant 
velocity universal joint, the balance of which is not illustrated. The 
journal 9 is provided, at an end thereof away from the universal joint, 
with longitudinal teeth 9a. These teeth are arranged to be engaged by 
corresponding teeth 11 formed on a ring 12, which will be described in 
greater detail hereinafter. 
The wheel hub 1 is also provided with an obliquely extending set of teeth 
1a and the ring 12 is likewise formed with a complementary set of teeth 13 
which operate to engage in the teeth 1a of the wheel hub 1. 
Thus, it will be seen that by engagement of the teeth 11 with the teeth 9a 
in the journal 9 and by engagement of the outer teeth 13 of the ring 12 
with the teeth 1a of the wheel hub 1, the wheel hub 1 and the journal 9 
are rotatably coupled for torque transmitting engagement therebetween. 
The members 9 and 1 are at least partially coaxial and rotate about a 
common rotational axis. It will be seen that the teeth 9a and 11 are 
arranged to extend generally parallel to the rotational axis and that the 
teeth 1a and 13 are arranged to extend obliquely relative thereto. 
As indicated in FIGS. 1 and 2, the wedge-shaped or triangular cross-section 
of the ring 12 is formed with a wedge angle .alpha. which is approximately 
15.degree. to 45.degree., and which in a preferred embodiment of the 
invention is 30.degree.. 
In an untensioned condition, there is a clearance of approximately 0.05-0.2 
mm between the teeth 9a of the journal 9 and the teeth 11 of the ring 12. 
The outer teeth 13 of the ring 12 of course engage, in turn, into the 
corrspondingly designed counter teeth 1a of the wheel hub 1. 
The assembly is provided with a nut 15 which is screwed onto the 
journal-like projection 9 of the outer joint member 10 by means of threads 
14 in order to exert an axial pressure onto the ring 12 while it is being 
tightened. By selection of suitable material, the ring 12 may therefore be 
elastically deformed. Deformation may be such that it may even extend into 
the plastic range. This not only ensures a non-rotating connection between 
the journal 9 and the wheel hub 1, but it will also ensure above all a 
completely clearance-free connection. When tightening the nut 15, there is 
an additional advantage in that there is provided a wedge-shaped 
configuration for the ring 12. The advantage arises in that the wheel hub 
1 including its cylindrical projection 3 are moved into the direction of 
the rotary constant velocity joint to such an extend that, by means of a 
collar 1b, the inner bearing ring 4 of the roller bearing may be pressed 
against a shoulder 10a of the outer joint member and, in the process, 
simultaneously tensioned relative thereto without causing any jamming of 
the bearing ring 4. Wedging of the ring 12 against the wheel hub 1 on the 
one hand, and the journal 9 on the other hand, is enhanced by designing 
the teeth 9a/11 and 1a/13 as pointed teeth. Accordingly, the inner teeth 
11 of the ring 12 are offset relative to the outer teeth 13 in such a 
manner that the point or apex of each of the teeth of one set of teeth and 
the tooth base between adjacent teeth on the other set of teeth will lie 
in a common plane. 
A modification of the embodiment of the invention is shown in FIG. 2 
wherein a drive shaft 16 is connected with the bearing assembly instead of 
the rotary constant velocity universal joint. In the embodiment shown in 
FIG. 2, the axial pressure acting on the ring 12 is also caused or 
generated by a nut 15. However, in contrast to the embodiment depicted in 
FIG. 1, in the assembly shown in FIG. 2, the nut 15 is formed with an 
external thread 17 which cooperates with an internal thread 16a of the 
drive shaft 16. 
FIGS. 3 and 4 illustrate in greater detail the ring or annular member 12 
shown as a separate individual component. The ring 12 is formed with a 
bore 18 which is provided with internal teeth 11 and an inclined outer 
face which is provided with the external teeth 13. The wedge shape or 
triangular configuration of the cross-section of the ring is depicted and 
the oblique outer face of the ring is formed with the teeth 13. The inner 
teeth 11 are arranged so as to be parallel to the axis of rotation of the 
member upon which the ring 12 is to be mounted. An angle .alpha. is formed 
between the oblique teeth 13 and the parallel teeth 11 and this angle, as 
best seen in FIG. 4, is approximately 15.degree. to 45.degree., but 
preferably 30.degree.. The ring 12 is formed with an end face 19 which 
serves as a stop or pressure face for the nut 15 in order to receive the 
axial pressure produced from tightening of the nut 15. 
In FIG. 5 there is shown apparatus for forming the ring 12. The apparatus 
comprises a pressing tool 20 which serves for producing, in a manner that 
does not involve cutting or chip formation, the ring 12 together with its 
teeth 11 and 13. The ring 12 is produced by precision forming and more 
particularly by cold forming. The ring is formed from a blank 22 which is 
shown in its unmachined condition and a pressing die 21 is also provided. 
Thus, it will be seen that the present invention provides a device for 
tranferring torque from a driving part to a driven part, with the transfer 
of torque occurring in a clearance-free manner. The device of the present 
invention may be used for constant velocity universal joints particularly 
in driving assemblies for motor vehicle wheels. 
The objectives of the invention are achieved by means of a metallic, 
elastically and/or plastically deformable ring having a cylindrical face 
carrying outer teeth and inner teeth arranged so as to be parallel 
relative to the axis of rotation of the assembly wherein an angle .alpha. 
of approximately 15.degree. to 45.degree. is formed between the inner and 
outer teeth, with the angle being preferably 30.degree.. 
While specific embodiments of the invention have been shown and described 
in detail to illustrate the application of the inventive principles, it 
will be understood that the invention may be embodied otherwise without 
departing from such principles.