Dual angular adjustment device for coarse and fine angular rotation of a shaft relative to a releasably connectable component

A device for adjusting the angular position of rotation of a steering wheel hub of a motor vehicle relative of a steering shaft utilizing a bushing which is located between these parts and connected to each of these by sets of teeth distributed uniformly over the inner and outer periphery of the bushing and wherein these teeth offer a large number of possibilities of angular adjustment as a result of the engagement of one set of teeth with the steering wheel hub for a coarse adjustment and as a result of the engagement of the other set of teeth with the steering shaft for an even larger possibility of minor angular adjustment.

BACKGROUND AND SUMMARY OF THE INVENTION 
The invention relates to a device for the fine adjustment of the angular 
rotative position of a shaft relative to a component releaseably connected 
thereto through a coupling bushing means which can be fixed on said shaft 
by means of a toothed surface uniformly provided on a periphery 
therebetween, and which can be positioned in cut outs of identical shape 
on the component by means of a further uniformly toothed surface wherein a 
large number of possibilities of angular adjustment between the shaft and 
the component are possible. 
European Preliminary Publication 0,148,794 describes a device, by means of 
which the angular position of a steering-wheel hub relative to a steering 
shaft, coaxial therewith, is obtained utilizing a bushing which is 
arranged between the shaft and hub, and is rotationally fixed to the 
steering shaft by means of a set of teeth and is displaceable on this 
connection in an axial direction. The bushing rotates the steering wheel 
hub by means of helically extending tooth flanks of a further toothed 
connection with the hub, wherein the steering shaft is thus caused to 
rotate relative to the steering wheel hub. 
This device makes it possible to cover a large angular range, which cannot 
be obtained by just changing the bushing on the steering shaft by the 
amount of one tooth for the exact alignment of the steering wheel hub 
relative to the steering shaft to which the vehicle wheels to be steered 
are connected. Rather, the solution described therein involves a large 
number of interfacing parts, and is therefore relatively expensive, since 
it is necessary to have both a drive for the axial displacement of the 
bushing and a complicated helical shape of the tooth flanks on the 
steering wheel hub, as well as having this complicated shape be given to 
the teeth of the bushing with which it engages. Moreover, the adjusting 
mechanism as a whole requires a large dimensional depth for the structure. 
An object of the instant invention is to provide a simple means to increase 
the number of possibilities of angular adjustment beyond those afforded by 
the normal toothed connection of a steering wheel shaft to a bushing, 
connected co-axially and releaseably between a steering wheel hub and 
shaft. 
The object is achieved by having a number of teeth in the toothed surface 
between the steering shaft and the bushing be much greater than a number 
of teeth in a toothed surface between the bushing and the steering wheel 
hub, whereupon a division of the larger number by the smaller number 
produces a remainder after the decimal point not equal to zero. 
Simply by changing the position of the bushing on the steering shaft and 
also in the steering wheel hub, the total number of possible angular 
adjustments increases to a value which is obtained from the possibilities 
of angular adjustment by means of one toothed connection multiplied by the 
different possibilities of angular adjustment of the other toothed 
connection, as a result of which a sufficiently exact alignment of the 
steering wheel hub on the steering shaft is achieved quite simply and with 
low costs. 
Since certain tolerances have to be allowed in the production of toothed 
connections, the bushing is braced by resting it frictionally against 
sloping faces so as to be able to transmit the steering torque if 
overloading occurs, as for example, due to an attempt to manipulate the 
steering wheel lock by over-rotating the steering wheel. The bracing can 
additionally be by plural faces on two flanks of the bushing. 
Additionally, it is possible to have the teeth, provided between the 
steering wheel hub and bushing, be either radially or axially engaged. It 
is also desirable to have a spring bracing the bushing, as well as having 
the bushing and spring located between the steering wheel hub and shaft, 
for transporting and ease of assembly purposes. 
It is also advantageous to the teeth on the steering wheel hub, which has 
relatively few teeth, be cast onto the steering wheel hub and be produced 
as unitary aluminum diecasting, since it is thereby possible to ensure 
production accuracy. 
Other objects, advantages and novel features of the present invention will 
become apparent from the following detailed description of the invention 
when considered in conjunction with the accompanying drawings.

DETAILED DESCRIPTION OF THE DRAWINGS 
FIGS. 1 and 2 show a steering wheel hub 1 and a bushing 2 which is inserted 
from an underside of the bore (to the left). The bushing 2 is engaged with 
the hub 1 by a set of teeth 3 distributed uniformly over the periphery and 
mating with corresponding teeth 9 on the hub 1. 
In order to keep the bushing 2 attached during transport or assembly so it 
will not fall out, a snap ring spring 5 is received in the bushing 2 and 
is braced slightly against the bore wall of the steering wheel hub 1. 
Along its inner bore surface, the bushing 2 has a further set of inwardly 
facing teeth 6 which fixedly secure a suitably serrated steering shaft 7 
in an non-rotational manner. The bushing 2 makes it possible to position 
the steering wheel hub 1 in eight angular positions of rotation relative 
to the bushing 2, due to the eight different relative rotational 
alignments of the cooperating sets of teeth 3 therebetween. The bushing 2 
can be positioned on the steering shaft 7 with sixty-six different 
possibilities of angular adjustment according to the sixty-six engaging 
teeth of its set of teeth 6. 
In this example, the bushing 2 is designed with two radially extending 
peripheral sets of teeth 3 and 6. The steering wheel hub 1 which has only 
a few teeth 9 has advantageously been cast in one piece with the steering 
wheel itself. 
During the assembly of the steering wheel hub 1 on the steering shaft 7, 
the steering wheel hub 1 is first slipped onto the steering shaft 7 as 
assembled together with the inserted bushing 2. At that time, a visual 
check is made as to whether, in this position, the steering wheel is 
aligned straight with the vehicle wheels. If there is a rotative offset 
which cannot be compensated by rotating the bushing 2, relative to the 
steering wheel hub 1 by the amount of an entire tooth 3, since the amount 
of the offset is less than arcuate distance between two adjoining teeth 3, 
then an intermediate value between two teeth of the sets of teeth 3 can be 
obtained by pulling off the steering wheel hub 1 together with the bushing 
2 and rotatably shifting the steering wheel hub 1 and the bushing 2 as 
unit in their angular position on steering shaft 7 by an amount of one or 
more teeth of the sixty-six teeth 6. This is possible since the number of 
possibilities of angular adjustment by means of the set of teeth 6 is not 
an integral multiple of the number of possibilities of angular adjustment 
by means of the other set of teeth 3. Consequently, the original rotative 
offset is converted into at most a very slight deviation in adjustment as 
a function of the arbitrarily selectable toothing ratios or possibilities 
of angular adjustment of the sets of teeth 3 and 6. 
After the steering wheel hub 1 is pushed onto the steering shaft 7, 
together with the bushing 2, to assume the new angular position of 
rotation which has little or no relative offset, the steering wheel hub 1 
is subsequently fastened on the steering shaft 7 in the manner shown in 
more detail in FIG. 3. 
In the embodiment of FIGS. 3 and 4, a bushing 2 has, in addition to the 
internally facing peripheral bore set of teeth 6 engaging with a steering 
shaft 7, an axially end facing set of two teeth 10 for engaging into a 
plurality of eight different cut outs 11 in steering wheel hub 1. These 
sets of two teeth 10 in cooperation with eight different cut outs 11, 
produce eight different angular positions. In general, the number of 
possible angular adjustments between the bushing 2 and the hub Can be 
selected freely, according to the number of cut outs 11 provided in the 
hub. Again, as in FIG. 1, minor angular offset can be accommodated between 
internal teeth 6 and shaft 7. 
In this embodiment, the bushing 2 is held braced slightly in the steering 
wheel hub 1 by means of two leaf springs 5 to allow for transportation and 
assembly of the hub 1 to shaft 7. After correct adjustment of the steering 
wheel hub 1 and bushing 2 on the steering shaft 7, the are secured 
frictionally by means of a countersunk screw 12 screwed into the steering 
shaft 7. Tightening of screw 12 causes bushing 2 to be positioned by 
resting against sloping face 13 of the countersunk screw 12 and face 15 of 
hub 1, while hub 1 rests against slope 18 on shaft 7. This is necessary 
because certain tolerances have to be allowed in the production of the 
various sets of teeth, as a result of which a slight radial play can occur 
between the parts. However, if an upper limiting value of the effect of 
force is exceeded during the rotation of the steering wheel, the tooth 
flanks of the sets of teeth 3 and 6 are supported positively on one 
another. 
This bushing 2 also allows inexpensive adaptation to different steering 
shaft or steering wheel hub diameters, and in this case the steering wheel 
hub 1 and the steering shaft 7 remain unaffected by the adaptation. Only 
the relative thickness of the bushing 2 and/or its inner and/or outer 
diameters need be changed. 
While the internal teeth 6 are described as being on the bushing 2 for 
wedging action onto the steering shaft 7, cooperating teeth could be 
provided on the shaft for intermeshing with these internal teeth 6. The 
above described adjusting device is utilized in a vehicle steering system 
such as shown in FIG. 5 wherein the steering wheel is connected to the 
steering shaft 7 by the aforementioned adjustment device and wherein the 
steering shaft turns the vehicle road wheels 20 through a conventional 
steering gear 22 and linkage 21. Alternatively, teeth 6 on the shaft could 
be wedged into a smooth surface on the bushing 2. No separate figure for 
this is shown, since the assembled bushing and shaft under these 
alternatives would appear as shown in FIG. 4. 
Although the present invention has been described and illustrated in 
detail, it is to be clearly understood that the same is by way of 
illustration and example only, and is not to be taken by way of 
limitation. The spirit and scope of the present invention are to be 
limited only by the terms of the appended claims.