Fastening means for axially securing machine elements and method therefor

Means for securing a machine element such as a bearing assembly on a shaft member or the like provided with an annular groove comprising an angular ring (14) having a radially outwardly directed leg portion (15) which abuts against an axial end face of the inner ring component to be secured and an axial leg portion (16) which is pressed into the annular groove (17) of the shaft or the like at least at a plurality of circumferentially spaced locations about its periphery.

BACKGROUND AND SUMMARY OF THE INVENTION 
The present invention relates to a fastening arrangement for axially 
securing machine elements and has particular application to installing 
rolling bearings without clearance or preloaded on a shaft or the like and 
a method for assembly thereof. 
A known process for producing such an arrangement is illustrated in German 
preliminary application No. 2,204,831. In accordance with the teachings of 
this prior invention, the preloading is applied exclusively to the machine 
element to be fastened by means of a radially acting tool which in 
addition to applying the deformation forces also must apply the preloading 
forces to the machine element. Accurate preloading force is necessary, for 
example, in rolling bearing applications which are installed without 
clearance or preloaded and in accordance with this prior teaching this 
accuracy cannot easily be obtained. Furthermore, the geometric 
configuration of the fastening ring is such to produce large area pressure 
on the relatively small contact surface which in some instances results in 
plastic deformation at these interengaging locations and with the result 
that the preloading is destroyed. For example, the machine element is in 
the form of a conically deformed ring which rests with a conically-shaped 
front face against the rounded edge of the roller bearing. Thus, with high 
axial preloading forces and/or with high operational axial forces, the 
area pressure on the relatively small contact surface has been found to be 
excessive and as noted above results in diminution or elimination of the 
preloading. The ring-like machine element is then no longer sufficiently 
secured or mounted in the precisely provided location to achieve the 
preloading and without clearance mounting of the bearing. In some 
instances this may lead to operational interruptions and premature failure 
of the bearing. Finally, these prior machine elements are thin-walled 
bushing-shaped rings that tend to bend as a result of the forces applied 
during operation and the mounting or fastening, therefore, tends to 
loosen. The ring may also loosen under high RPM's and resulting high 
centrifugal forces. 
With the foregoing in mind, it is an object of the present invention to 
provide an arrangement for axially fastening or securing machine elements 
which makes it possible on the one hand to apply an accurately determined 
preloading to the machine element to be fastened such as the inner rings 
of a bearing assembly and on the other hand supports the machine element 
over a relatively large surface area additionally securing and accurately 
fastening the machine element even under the highest loads. To this end, 
there is provided a closed bushing-shaped ring of angular or L-shaped 
cross section which is adapted to be conically deformed by plastic 
deformation at one end thereof remote from the machine element to be 
fastened in such a way that the corresponding front face thereof enters in 
an annular groove in a shaft member or the like away from the machine 
element. Specifically the ring is constructed as an angular ring of 
L-shaped cross section wherein the radially outwardly directed leg abuts 
against the front fact of the machine component to be fastened and the 
axially extending leg portion is pressed in an annular groove in the shaft 
or the like at least at several circumferentially spaced locations about 
its periphery. By reason of the angular configuration of the ring 
including the radially outwardly directed leg portion, it is possible 
during the mounting process to apply a preload force to the machine 
element such as the inner rings of a double row ball bearing assembly 
independently of the deformation force when the preload force is applied 
to this leg by means of a suitable deforming tool. On the other hand, the 
axial end face of the radial leg portion confronting the machine element 
provides a large contact zone between the two and in addition stiffens or 
strengthens the ring and prevents in this fashion bending under high loads 
and consequent loosening thereof. 
In order to further rigidify the mounting of the ring and prevent loosening 
thereof, the bore of the angular ring may be made of slightly smaller 
diameter than the outer diameter of the shaft on which it is mounted to 
produce an additional press fit. 
In accordance with another feature of the present invention, the fastening 
arrangement additionally includes a second annular member which engages 
over the axial leg portion of the angular ring with a press fit. This 
second ring may include internal threads which cooperate and engage with 
threads on the shaft member located adjacent the annular groove on the 
shaft member or the like. When the angular ring is press fitted this 
arrangement contributes to maintaining the angular ring in an accurate 
position and at least part of the axial forces are transmitted or absorbed 
by the press fit. The second ring engaging over the axial leg portion may 
be installed by a shrink fit or the like and it serves to prevent the 
deformed end of the angular ring from breaking up under load and 
consequent loosening which is harmful to maintaining the desired 
preloading of the assembly.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring now to the drawing and particularly to FIG. 1 thereof, the 
machine element fastening means of the present invention is illustrated in 
a wheel bearing assembly. These assemblies typically comprise an outer 
ring 1 having a radially outwardly directed flange 2 with bolt openings 2a 
for securing the bearing to the frame of the vehicle, an inner ring 5, 
consisting in the present instance of two annular inner ring members 3 and 
4. The inner and outer rings have confronting spaced raceways for a 
plurality of rolling elements, balls 8 arranged in two rows. The balls in 
each row are circumferentially spaced by conventional cages 6 and 7. The 
inner rings are mounted on the outer peripheral surface of a body member 
10 of a homokinetic joint 11, the inner ring 3 abutting at one axial end a 
shoulder 12 formed in the outer body portion 10 which also has a radial 
flange 13 with bolt holes 13a for mounting a wheel rim (not shown). 
In accordance with the present invention, means are provided for preloading 
the rolling elements in a manner firmly securing the inner ring members 
against the shoulder 12. To this end, there is provided an angular ring 14 
having a radially outwardly directed circumferentially extending leg 
portion 15 which abuts the axial outer end face 4a of the inner ring 
component 4. The angular ring 14 made of a deformable metal such as 
deep-drawing steel also includes an axially extending leg portion 16 
adapted to be deformed inwardly in such a manner that it engages in an 
annular groove 17 in the outer peripheral surface of the body portion 10. 
The annular groove 17 as illustrated is of generally triangular cross 
section so that the leg portion 16 is supported in an axial direction on 
the flank 18 of the annular groove 17. Note that initially the angular 
ring 14 is shown on the right-hand side of FIG. 1 prior to assembly and 
after it is positioned over the body member, it is deformed into the 
annular groove 17 at a plurality of circumferentially-spaced locations by 
a radially or essentially radially acting tool. For enduring deformation 
of the axial leg portion 16, an axial force is applied to the radial leg 
portion 15 which preloads the two inner ring components 3 and 4 and, 
therefore, preloads the rolling elements or balls of each row with respect 
to each other. 
If desired, the bore 19 of the angular ring 14 may be of a smaller diameter 
than the diameter of the outer surface 9 of the body portion 10. In this 
instance, the angular ring may be heated prior to installation to expand 
it slightly and permit easy assembly to the body portion and after 
cooling, the angular ring shrinks to provide an additional press fit with 
the body portion which increases the holding action of the angular ring 
14. 
There is illustrated in FIG. 2 a modified version of the fastening means in 
accordance with the present invention. The hub unit assembly with which 
the fastening means is utilized is essentially the same as that described 
previously and accordingly carries the same reference numerals. In 
accordance with this embodiment, the fastening means includes the angular 
ring 14b, and in this instance the axial leg portion 16b thereof is 
deformed into the angular groove 17 over its entire periphery and 
thereafter an additional second fastening ring 20 is mounted over the 
deformed leg portion 16b of the angular ring 14b. In the present instance 
the ring has internal threads 21 which cooperate with a threaded 
projection 22 on the outer peripheral surface 9 of the body portion 10. 
The second ring 20 has a conical internal face which confronts and engages 
the conical outer face of the leg portion 16b to thereby secure it against 
a reverse deformation or spring back and thereby guarantee a firm mounting 
arrangement which can withstand heavy loading even under severe operating 
conditions such as high RPM's and resultant high centrifugal forces which 
would tend to loosen the angular ring 14b during operation. The secondary 
ring 20 also serves to fasten a bellow 24 for sealing the homokinetic 
joint assembly 11. 
Even though particular embodiments of the invention have been illustrated 
and described herein, it is not intended to limit the invention and 
changes and modifications may be made therein within the scope of the 
following claims.