Note: Descriptions are shown in the official language in which they were submitted.
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Whee! Bearing Assemb/ies lncorporating Sensing Arrangements
The present invention relates to vehicle wheel bearing assemblies and more
particulariy to such assemblies equipped with sensing arrangements for sensing
rotary
speed or position.
In this field there have been many prior art constructions which can be taken
to
form the background for the invention. In general, rotary bearings employing
sensing
arrangements for sensing rotary speed or position can employ a pre-fabricated=
annular
component made of polymeric materiai containing ferrous material which is
treated to
form aitemate north and south magnetic poles, see for example, US Patent
5089817.
Such a component referred to as an encoder can be mounted in the assembly to
cause
the magnetic poles to pass alongside a sensor, such as a Hall effect sensor,
which
generates a pulsed electrical signai.
An object of the present invention is to provide improved assemblies and
sensing
arrangement$ of the aforementioned kind.
Accordingly the present invention provides a wheel bearing assembly composed
of
Inner and outer bearing rings, one of which is intended to rotate and the
other of which Is
intended to remain stationary, two sets of rolling elements between the rings
and in
angular contact with=tracks defined by the rings, each set of rolling elements
being
spaced in the direction of the axis of rotation with each set of roiiing
elements retained by
one of two cages and a sensing arrangement composed of at least two annular
i
encoders with aitemate north and south magnetic poles and at least two sensors
operably associated with the encoders and each serving to provide eiectrical
signals
generated by the passage of the poles of the associated encoder;
wherein one of the encoders is mounted on the rotatable one of the bearing
rings
and,
the other of the encoders is mounted on one of the cages and
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each of said sensors and encoders is disposed axially, between the sets of
rolling
elements.
The encoder can be mounted on different components of the assembly such as on
one of the cages and on the rotatable bearing ring. This enables the signals
generated
by the sensors to be compared, for example. The encoders can be orientated
with their
magnetic poles parallel to the rotational axis thus in an axial orientation or
radial to this
axis thus In a radial orientation or in both axial and radial orientations.
The sensors and
encoders may be built into the bearing in a protected position between the
sets; of rolling
elements. To locate the sensors use can be made of a housing or a mounting'as
described hereinafter.
In other embodiments the sensors and encoders lie outboard of the bearing and
the wheei assembiy for ease of installation or removal. A second aspeCt of the
present invention provides a wheel bearing -assembly
composed of inner and outer bearing rings, one of which is intended to rotate
and the
other of which is intended to remain stationary, sets of rolling elements
between the
rings and in angular contact with tracks defined by the rings, the sets of
rolling elements
being spaced in the direction of the axis of rotation with each set of rolling
elements
retained by a cage and a sensing arrangement composed of at least two annular
encoders with altemate north and south magnetic poles and at least two sensprs
operably associated with the encoders and each serving to provide electrical
signals
generated by the passage of the poles of the associated encoder;
wherein one of the encoders is mounted on the rotatable one of the bearing
rings
and,
the other of the encoders is mounted on one of the cages and wherein the inner
bearing ring is secured onto a wheel hub, a cover is located on the other
bearing ring to
enclose the sensors and is carried by an axial portion of the cover.
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'T'he invention may be understood more readily, and various other aspects and
features of the Invention may become apparent, from consideration of the
foliowing
descript-on.
Wheel bearing assembiies embodying the invention will now be described, by way
of examples only, with reference to the accompanying drawings, wherein:
Figure 1 is a schematic sectional side view of a first embodiment of a wheel
bearing assembly;
Figure 2 is an enlarged view of part of the assembly shown in Figure 1;
Figure 3 is a schematic sectional side view of a second embodiment of a=wheel
bearing assembly;
Figure 4 is a schematic sectional side view of a third embodiment of a wheel
bearing assembly,
Figure 5 is a schematic sectional side view of a fourth embodiment of a wheei
bearing assembly,
i S Figure 6 is a schematic sectional side view of a fifth embodiment of a
wheel
bearing assembly,
Figure 7 is a schematic sectional side view of a sixth embodiment of a wheel
bearing assembly,
Figure 8 is a schematic sectional side view of a seventh embodiment of a wheel
bearing assembly
Figure 9 is a schematic sectional side view of an eighth embodiment of a wheel
bearing assembly. The constniction of the various wheel bearing assemblies 9
illustrated throughout
the accompanying drawings is well known parse and like reference, numerals are
used
to designate the same components.
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Refercing initially to Figure 1, there is an inner bearing ring 10, an outer
beartng
ring 11 and two sets or rows of rolling elements in the form of balls 12
therebetween.
The bails 12 make angular contact with ninning tracks 13, 14 in the rings 10,
11. In this
assembiy, the right-hand or innermost track 14 of the ring 10 is actually
formed by a
separate support 15 located in a recess 8 in the inner ring 10. A wheel hub is
fixed to or
integral with the inner ring 10 and receives a nut 16 which locates on the
support 15. A
detachable pressing fits into an outer projecting region 5 of the outer ring
11 and acts as
a cover 6 for the nut 16. At the opposite left-hand or outemnost end regions
of the rings
10, 11 there is a seal 17. Each set of balls 12 is fitted into a cage 18, 19
made of
plastics materiaL As is known, the cages 18, 19 maintain separation between
the balls
12 and guide the balls 12 making up each set for progression around the tracks
13, 14.
During use, the inner rina 10 rotates with the wheel hub whilst the outer ring
11 = remains
stationary. The balls 12 progressively roll in relation to the tracks 13, 14.
In accordance with the invention, the assembly 9 is equipped with a sensing
arrangement designed to provide an indication of rotary speed or positlon_ As
shown in
Figures 1 and 2, the cage 19 has an axial projection 20 which extends
outwardly towards
the other ball set. A first pre-formed annular encoder 21 with aitemate
axially-orientated
north and south magnetic poles is fitted onto an axial surface 22 of the
projection 20 to
confront the inner surface of the outer ring 11, A second pnr-formed annular
encoder 23
with afterrmate north and south axially-orientated magnetic poles is fitted
onto the inner
surface of the inner bearing ring 10. The encoders 21. 23 are axially and
radially offset
in relation to one another.
A radial bore 24 in the oqter ring 11 receives a housing 25, As shown in
Figure 2,
the inner end of the housing 25 has a stepped profile with end wafls 26, 27
offset in the
radial direction. The end walls 26, 27 mount sensors 28, 29 which detect the
passage of
the magnetic poles of the encoders 21, 23 and provide pulsed electrical
signals with a
repetition frequency depending on the movement of the poles of the encoders
21, 23.
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The signals ere carried on leads 30, 31 connected with the sensors 28, 29_ The
signals
from the sensor 28 represent the rotary speed of the cage 19 while the signals
from the
sensor 29 represent the rotary speed of the inner ring 10. The signals can be
used in a
variety of ways quite separately and independently or combined or compared
with one
another.
Figure 3 shows a modified form of the sensing arrangement shown in Figures 1
and 2. In this arrangement, the encoder 23 is mounted on a support ring 32
fitted to the
inner surface of the inner bearing ring 10 and the magnetic poles of the
encoders 22, 23
lie in a common axial plane. The associated sensors 28, 29 are iikewise
orientated in a
] 0 common axial plane corresponding to the inner surface of the outer ring
11. The
sensors 28, 29 are mounted at the inner end of a bore 24 in the ring 11. The
leads 30,
31 are used to support and position the sensors 28, 29 and these leads 30, 31;
emerge
from the bore 24.
In the embodiments described and illustrated so far the encoders and sensors
21,
23, 28, 29 are all inboard between the sets of balls 12.
In other constructions the encoders and sensors can be outside the bearing
interior. Thus, Figure 4 shows another sensing arrangement with two encoders
21, 23
and two sensors 28, 29. The first encoder 21 is again located on an axial
projection 20
of the cage 19 but in this embodiment the projection 20 extends outwardly
rather than
inwardly. The second encoder 23 is mounted on an axial region of a further L-
shaped
ring 33 disposed outside the bearing_ A radial region of this ring 33 is
clamped by the
nut 16 against the support 15. As with the arrangement shown in Figure 3, the
magnetic
poles of the encoders 21, 23 lie in a common axial plane as do the opposed
associated
sensors 28, 29 which are now supported on an axial portion 34 of the cover 6.
In the assemblies and arrangements depicted in Figures 1 to 4 the encoders 21.
23 and the sensors 28, 29 are located predominantly in the axial disposition.
Figures 5
and 6 show somewhat different arrangements where the encoders 21. 23 and the
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sensors 28, 29 take a radial disposition. In the arrangement shown in Figure 5
the
encoder 21 is mounted on an outermost radial surface 35 of the outer cage 19
so the
magnetic poles take a radial orientation. The encoder 23 is here mounted on a
plane
washer 36 clamped between the nut 16 and the support 15. As can be seen, the
encoders 21, 23 are both axially and radially offset. The associated sensors
28, 29 are
likewise axially and radially offset and suspended, for example, by a
deformabie sleeving
surrounding the leads 30, 31 and bent into an L-shape. The sleeving can be
secured to
the axial portion 34 of the cover 6 in any suitable fashion.
Figure 6 shows another arrangement with the encoders 21, 23 and the sensors
28,
29 all in a radial orientation. In this arrangement, the encoder 21 is
supported on the
innermost radial end face 35 of the cage 18. The encoder 23 confronts the
encoder 21
and is radially aligned but axially offset with respect to the encoder 21. A
suppOrt ring 39
fits into a recess 43 in the inner surface of the inner bearing ring 10 and
the support ring
39 serves to mount the encoder 23. The associated sensors 28, 29 are again '
suspended by their leads 30, 31 in the sensor vicinity of the encoders 21, 23.
The leads
30, 31 pass through the bore 24 in the bearing ring 11.
Figure 7 shows an arrangement where the encoders 21, 23 and the sensors 28, 29
are orientated both radially and axiaiiy_ Thus, the encoder 21 is again
mounted on the
radial surface 35 of the cage 18 as is in the embodiment shown in Figure 5.
However
the washer 36 is now L-shaped with an axial region 37 supporting the encoder
23 in an
axial orientation generally normal to the orientation of the encoder 21. A
tubuiar housing
again secured to the axial portion 34 of the cover 6 accommodates the s+ensors
28,
29, The.housing 25 has a radially orientated- inner end wall 38 supporting the
sensor 28
in the sensing vicinity of the encoder 21 and an axial wall 39 supporting the
sensor 29 in
25 the sensing vicinity of the encoder 23.
Figure 8 depicts a similar arrangement to Figure 6 but here the shape and mass
of
the support ring 37 for the encoder 21 is modified. The ring 39 Is now L-
shaped and has
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an axial flange portion 41 fitted directly to the inner surface of the inner
ring 10 which is
no longer provided with a recess.
Figure 9 is again similar to the arrangement shown in Figure 8 but here the
encoder 21 is fixed to the cage 18 with screws. In this arrangement the
mounting of the
sensors 28, 29 is achieved with the aid of a mounting bfock 42. The mounting
block 42
has a flange 43 affixed with screws 44 to the outer bearing ring 11. A bore 45
in the
block 42 is co-axial with the bore 24 in the ring 11. An elongate carrier 46
extends
through the bores 45, 24 and mounts the sensors 28, 29 face-to face in
opposite
directions. A further screw 47 is received in a wall of the block 42 to
penetrate. the bore
45 and the screw can be used to adjustably locate with the carrier 46.
In the assernbiies and arrangements depicted in the drawings and described
hereinbefore there is two encoders and two sensors. In Figure 10 a modified
arrangement is depicted which uses three encoders and three sensors. Thus in
Figure
10 a first encoder 21 is mounted on an outer end surface 35 of the cage 18 and
takes a
radial orientation. A second encoder 23 is rnounted on the inwardly directed
end face 48
of the cage 19 in confronting relationship to the encoder 21 and iikewise take
a radial
orientation. The encoders 21, 23 are in radial alignment but spaced apart
axially. A third
encoder 49 is mounted on a support ring 50 fitted in a shallow recess 51 in
the inner
surface of the inner ring 10. The third encoder 49 takes an axial orientation.
The
sensors associated with the encoders are again supported by a common housing
25
located in their bore 24 in the outer bearing ring 11. In this case the
radially orientated
sensors 28, 29 associated with the encoders 21, 23 are located in an annuler
ridge
portion. 52 at the end of the housing 25 while a further sensor 53 associated
uiith the
third encoder 49 and located in an axiai orientation is located centrally of
the inner end of
the housing 25 within the end ridge portion 52 and radially offset therefrom.
