Wheel spindle retention for a non-driven vehicle wheel

In a wheel mounting arrangement which comprises a wheel-attachment spindle rotatably carried by roller bearings within a bearing hub and clamped thereto by a nut received on a threaded end of a spindle shaft, a locking device for preventing removal of the nut from the spindle shaft and consequent detachment of the spindle and spindle-attached wheel from the bearing hub and vehicle. The device comprises a locking snap ring received in a circumferential groove in the threaded spindle end so as to block removal of the nut. In accordance with a particular and critical feature of the invention, the groove and locking ring are axially spaced from the opposing surface of the nut in assembly and in normal operation so that the ring cooperates with the nut opposing surface to permit limited loosening of the nut. This feature permits limited axial movement of the spindle shaft with respect to the bearing and bearing hub causing an audible rattling sound which will warn the vehicle operator that the associated spindle nut should be retightened or otherwise serviced.

The present invention is directed to wheel mounting devices, and more 
particularly to a device for retaining or locking the spindle of a 
non-driven vehicle wheel so as to prevent detachment of the wheel from the 
vehicle. 
Mounting arrangements for non-driven vehicle wheels, such as the rear wheel 
of a front wheel drive automobile, conventionally comprise a 
wheel-attachment spindle rotatably carried by roller bearings within a 
bearing hub and clamped thereto by a nut received on the threaded inboard 
end of the spindle shaft. In mounting arrangements of this type, the nut 
may become loosened and removed from the spindle, particularly in the 
event of bearing failure, after which the wheel-attachment spindle and the 
wheel itself may become detached from the bearing hub and vehicle. 
A general object of the present invention is to provide a mounting 
arrangement of the described type wherein removal of the mounting nut from 
the spindle, and consequent potential detachment of the spindle and wheel 
from the bearing hub and vehicle, is prevented. A further and more 
specific object of this invention is to provide a nut and spindle locking 
device which satisfies the foregoing objective, which is economical, which 
may be readily assembled in the factory, and/or which may be readily 
disassembled and reassembled in the aftermarket service environment. Yet 
another object of the invention is to provide a wheel and spindle locking 
device of the described type which operates in such a way that a vehicle 
operator will be warned that the spindle-mounting nut has become loosened 
and must be retightened or otherwise serviced. 
To accomplish the foregoing and other objectives of the invention, a 
locking ring is received in a circumferential groove in the threaded 
spindle end so as to block removable of the nut. In accordance with a 
specific and critical feature of the invention, the groove and locking 
ring received therein are axially spaced from the opposing surface of the 
nut in assembly and during normal operation so that, in the event of 
loosening of the nut, the nut is permitted a limited number of turns 
before abutment with the locking ring. This feature permits limited axial 
movement of the spindle with respect to the bearings and bearing hub, 
causing rattling at the wheel which thereby warns a vehicle operator that 
the particular wheel nut must be retightened or otherwise serviced.

FIGS. 1-3 illustrate a presently preferred embodiment of a wheel spindle 
and bearing hub carrier assembly 10 in accordance with the invention as 
comprising a bearing hub or bearing cap carrier 12 having a radiating 
integral external flange 14 for mounting hub 12 to a vehicle frame axle or 
the like (not shown). A pair of tapered roller bearings 16,18 are mounted 
internally of hub 12 and have outer races spaced from each other by the 
circular shoulder 19. A wheel-attachment cartridge bearing spindle and 
bolt sub-assembly 20 includes a stub shaft 22 rotatably internally carried 
by roller bearings 16,18 and an integral flange 24 radiating from an 
outboard end of shaft 22. (It will be appreciated that the terminology 
"inboard" and "outboard" are taken with reference to preferred orientation 
with respect to an associated vehicle.) A plurality of threaded studs 26 
are mounted in a circumferential array on flange 24 in the usual manner 
for attachment thereto of a vehicle wheel and brake rotor, etc. (not 
shown). Shaft 22 terminates in a threaded inboard end 24 of reduced 
diameter which receives a nut 26 for clamping shaft 22 and thus spindle 20 
to the inner races of bearings 16,18 in cooperation with the nut-opposing 
spindle shoulder 28. A dust cap 30 is received internally of bearing hub 
14 over nut 26. Spindle and bearing hub assembly 10, to the extent thus 
far described, is generally conventional in construction. 
In accordance with the present invention, locking means generally indicated 
at 32 are provided to retain nut 26 on threaded shaft end 24, and thereby 
to prevent detachment of spindle 20 and the associated spindle-mounted 
wheel (not shown) from the vehicle. In accordance with a preferred 
embodiment of the invention illustrated in FIGS. 1-3, locking means 32 
comprises a split retaining ring 34 received by snap-fit in a 
circumferential groove 36 formed in the threaded end 24 of shaft 22. As 
best seen in FIG. 3, nut 26 is step counterbored at its inboard end to 
form an internal shoulder 38 in the inboard face 40 of nut 26 
circumferentially surrounding the threaded opening of the nut and axially 
overlapping ring 34 in assembly. Shoulder 38 includes a first cylindrical 
counterbored shoulder portion 42 radially aligned in assembly with groove 
36 and of a diameter sufficient to permit circumferential radial expansion 
of ring 34, using an appropriate tool (not shown), and assembly of ring 34 
into groove 36 after nut 26 has been threaded onto shaft 22 such that 
outboard nut face 44 is snug against the inner race of roller bearing 18. 
Shoulder 38 also includes a second cylindrical counterbored shoulder 
portion 46 of lesser diameter than, and extending coaxially inwardly from, 
shoulder portion 42. Shoulder portion 46 has a predetermined diameter 
slightly greater than the diameter of ring 34 as received and held in 
groove 36 such that shoulder 46 has assembly clearance with snap ring 34 
but not enough clearance to allow ring 34 to be expanded out of groove 36. 
In operation in the event of loosening of nut 26, the nut is permitted 
threadably to rotate and thus have limited axial movement in the loosening 
direction away from inboard bearing 18 until the axially directed face 48 
of shoulder portion 46 abuts the opposing surface 49 of ring 34. At such 
position of abutment, further loosening of nut 26 is prevented by ring 34, 
and nut shoulder portion 46 of lesser diameter axially overlaps and 
restrains expansion of ring 34 from the radial direction and thereby 
prevents removal of the locking ring from groove 36. Such limited 
displacement of nut 26 with respect to shaft 22 and bearings 16,18 permits 
axial limited movement of the spindle with respect to the bearings and 
bearing hub, thereby producing an audible rattling sound which warns an 
operator of the vehicle that the associated spindle retaining nut requires 
retightening. In the event that one or both of the bearings 16,18 require 
replacement in the aftermarket, spindle 20 may be removed therefrom by 
first tightening nut 26 and then removing retaining ring 34 using an 
appropriate tool. Nut 26 may then be removed from shaft end 24 and the 
spindle shaft removed from within bearings 16,18. 
FIG. 4 illustrates a modified embodiment of the invention wherein the split 
retaining snap ring 50 and the ring-abutting inner shoulder portion 53 are 
circular in radial cross-section. The embodiment of FIG. 4 is otherwise 
identical in function and operation to that of FIGS. 1-3, with 
corresponding elements thereof being indicated by identical reference 
numerals followed by the suffix "a". 
FIGS. 5 and 6 illustrate a second modified embodiment of the invention 
wherein the split retaining snap ring is assembled on the spindle shaft 
prior to threading thereon of the spindle retaining nut. Referring to FIG. 
5, the ring-receiving circumferential groove 36b in threaded shaft end 24b 
has a diameter which is substantially less than the relaxed or free-state 
diameter of retaining ring 34b such that the retaining ring normally 
floats within the spindle groove 54 and may be circumferentially 
compressed therewithin to a diameter less than the root diameter of the 
spindle external threads. The internal shoulder 38b on nut 26b is of 
constant diameter slightly greater than the relaxed diameter of ring 34b, 
but less than the outside diameter of ring 34b when radially expanded to 
be clear of groove 36b. The outboard bearing-abutment face 44b of nut 26b 
includes a conical internal camming shoulder 56. 
In assembly, ring 34b is first expanded and slipped onto spindle shaft end 
24b until registered with and snapped into mounted position in groove 36b. 
Nut 26b is then threaded onto shaft end 24b. Upon engagement of nut 26b 
with retaining ring 34b as shown in FIG. 6, the retaining ring is 
circumferentially and radially compressed into groove 36b by the camming 
action of conical shoulder 56 so as to permit passage thereover of nut 26b 
as the same is further threaded onto shaft end 24b. As nut 26b is threaded 
into clamping engagement with the inner race of bearing 18 (FIG. 5), the 
internal threads of nut 26b move axially clear of ring 34b and shoulder 
38b is brought into axially overlapping, radial registry with retaining 
ring 34 such that the retaining ring is permitted to expand to its relaxed 
condition. The axial spacing between the axially directed nut face 48b and 
the opposing surface 49b of ring 34b operates to permit limited loosening 
of nut 26b in the manner previously described.