U.S. patent application number 09/902295 was filed with the patent office on 2003-01-16 for sensor for monitoring angular velocity.
This patent application is currently assigned to The Timken Company. Invention is credited to Karpinski, John L..
Application Number | 20030011358 09/902295 |
Document ID | / |
Family ID | 25415631 |
Filed Date | 2003-01-16 |
United States Patent
Application |
20030011358 |
Kind Code |
A1 |
Karpinski, John L. |
January 16, 2003 |
SENSOR FOR MONITORING ANGULAR VELOCITY
Abstract
A hub assembly for coupling a road wheel of an automotive
vehicle to the suspension system of the vehicle includes a housing
and a hub having a spindle which extends into the housing where it
rotates on a bearing having rolling elements arranged in two rows.
The spindle carries a target wheel between the two rows of rolling
elements, and the housing has a hole which opens into the space
between the two rows. Here the housing is fitted with a sensor that
monitors the rotation of the target wheel. The sensor has a bushing
which is within the hole and a probe which extends from the bushing
into the housing where it has a pickup area that is presented
toward the target wheel. The bushing is positioned within the hole
by an O-ring that is compressed between it and the surface of the
hole. The bushing also has a leading surface that leads up to the
O-ring and has a diameter only slightly less than the diameter of
the hole. It also has a trailing surface of lesser diameter on the
other side of the O-ring. The leading surface prevents the probe
from deviating from its desired position and facilitates
installation of the sensor in the housing.
Inventors: |
Karpinski, John L.;
(Massillon, OH) |
Correspondence
Address: |
POLSTER, LIEDER, WOODRUFF & LUCCHESI
763 SOUTH NEW BALLAS ROAD
ST. LOUIS
MO
63141-8750
US
|
Assignee: |
The Timken Company
|
Family ID: |
25415631 |
Appl. No.: |
09/902295 |
Filed: |
July 10, 2001 |
Current U.S.
Class: |
324/173 ;
324/174; 384/448 |
Current CPC
Class: |
G01P 3/446 20130101;
G01P 1/026 20130101; F16C 41/007 20130101; F16C 19/386 20130101;
F16C 2326/02 20130101 |
Class at
Publication: |
324/173 ;
324/174; 384/448 |
International
Class: |
G01P 003/48; G01P
003/54 |
Claims
What is claimed is:
1. In combination with a housing that contains a hole having a
generally cylindrical wall and a target wheel that rotates within
the housing and has discontinuities, a sensor which detects
movement of discontinuities on the target wheel as a consequence of
rotation of the target wheel and produces a signal which reflects
the angular velocity of the target wheel, the sensor comprising; a
bushing located within the hole and having an axis and inner and
outer ends, the bushing also having a leading surface and trailing
surface, both of which are presented toward the surface of the
hole, with the leading surface having a diameter greater than the
trailing surface; an annular elastomeric element encircling the
bushing between the leading and trailing surfaces and being
compressed between the bushing and the surface of the hole; and a
probe extended from the inner end of the bushing and into the
interior of the housing, the probe having a pickup area that is
presented toward the target wheel.
2. The combination according to claim 1 wherein the bushing of the
sensor contains an annular groove that opens toward the surface of
the hole between the leading and trailing surfaces; and wherein the
elastomeric element is in the groove.
3. The combination according to claim 2 wherein the sensor further
has a head at the outer end of the bushing, with the head being
larger than the hole and providing a shoulder which is presented
toward the housing.
4. The combination according to claim 2 wherein the leading surface
is tapered and has its greatest diameter toward the groove.
5. The combination according to claim 4 wherein the smallest
diameter of the tapered surface on the bushing does not exceed the
diameter of the trailing surface.
6. The combination according to claim 5 wherein the smallest
diameter of the tapered surface is substantially equal to the
diameter of the trailing surface.
7. The combination according to claim 2 wherein the leading surface
is cylindrical.
8. The combination according to claim 1 wherein the diameter of the
hole exceeds the greatest diameter of the leading surface by
between about 0.001 and about 0.004 inches.
9. The combination according to claim 1 wherein the pickup area is
on the side of the probe.
10. The combination according to claim 9 wherein the axis of the
hole is oblique to the axis of rotation for the target wheel.
11. A sensor comprising: a bushing having an axis and inner and
outer ends along the axis and also an annular groove located
between the ends and opening away from the axis, the bushing
further having a generally cylindrical trailing surface between the
groove and the outer end and a circular leading surface between the
groove and the inner end, with the leading surface having a
diameter exceeding the diameter of the trailing surface; an annular
seal element located in the groove, the seal element being formed
from an elastomer and, when undistorted, having a diameter greater
than the diameter of the leading surface; and a probe extended from
the inner end of the bushing and being capable of detecting the
movement of discontinuities past it.
12. A sensor according to claim 11 wherein the diameter of the
leading surface exceeds the diameter of the trailing surface by
between about 0.004 in. and about 0.006 in.
13. A sensor according to claim 11 and further comprising a head at
the outer end of the bushing, the head being larger than the
bushing.
14. A sensor according to claim 11 wherein the leading surface is
tapered and the smallest diameter of the tapered leading surface
does not exceed the diameter of the cylindrical trailing
surface.
15. In combination with a hub that is located around an axis of
rotation and has a flange and a spindle projecting from the flange,
a first inner raceway carried by the spindle adjacent to the flange
and oriented oblique to the axis, a second inner raceway carried by
the spindle and also oriented oblique to the axis, but being
inclined in the direction opposite to the inclination of the first
inner raceway, the second inner raceway being spaced axially from
the first inner raceway; a housing located around the spindle of
the hub; a first outer raceway carried by the housing and presented
toward the first inner raceway, the first outer raceway being
oblique to the axis and inclined in the same direction as the first
inner raceway; a second outer raceway carried by the housing and
presented toward the second inner raceway, the second outer raceway
being oblique to the axis and inclined in the same direction as the
second inner raceway, the second outer raceway further being spaced
axially from the first outer raceway so that an intervening surface
exists between the first and second outer raceways; first rolling
elements arranged in a row between the first inner and outer
raceways; and second rolling elements arranged in a row between the
second inner and outer raceways; the improvement comprising: a hole
extended through the housing and opening into the housing through
the intervening surface; the hole having a substantially
cylindrical surface; a target wheel carried by the spindle between
the first and second inner raceways and having discontinuities
along it, whereby the target wheel will rotate when the hub
rotates; and a sensor carried by the housing for monitoring the
rotation of hub, said sensor comprising a bushing located within
the hole, an annular elastomeric element compressed between the
bushing and the cylindrical surface of the hole, and a probe
extended from the bushing into the interior of the housing, the
bushing having leading and trailing surfaces that are within the
hole with the leading surface being ahead of the elastomeric
element and the trailing surface being behind the elastomeric
element, and with the leading surface having a diameter greater
than the diameter of the trailing surface, the probe having a
pickup area that is presented toward the discontinuities on the
target wheel.
16. The combination according to claim 15 wherein the diameter of
the hole in the housing exceeds the diameter of the leading surface
on the bushing of the sensor by between about 0.001 in. and about
0.009 in.
17. The combination according to claim 15 wherein the
discontinuities on the target wheel are presented generally toward
one of the rows of rolling elements and the probe of the sensor
extends into the space between that row of rolling elements and the
target wheel.
18. The combination according to claim 15 wherein the sensor also
includes a head which is larger than the hole and lies outside the
housing and from which bushing extends.
19. The combination according to claim 15 wherein the bushing of
the sensor contains an annular groove that is located between the
leading and trailing surfaces and opens toward the surface of the
hole; and wherein the elastomeric element is in the groove.
20. The combination according to claim 19 wherein the leading
surface on the bushing is tapered and has its greatest diameter at
the groove.
Description
BACKGROUND OF THE INVENTION
[0001] This invention relates in general to sensing devices and,
more particularly, to a sensor for monitoring angular velocity.
[0002] Many automotive vehicles of current manufacture come
equipped with antilock braking systems and some with traction
control systems as well. In a vehicle so equipped, the systems
monitor the rotation of some, if not all, of the wheels--and
certainly the front wheels which steer the vehicle. Should a wheel
begin to slip when the brakes are applied, as could well occur if
the wheel encounters snow or ice, the antilock braking system will
detect the loss of velocity and relax the braking force on that
wheel. This allows the wheel to continue to rotate and enables the
driver to maintain better control over the vehicle. On the other
hand, if one of the driving wheels encounters slippery pavement and
as a consequence loses traction, the traction control system will
apply a braking force to that wheel, and this has the effect of
transferring the torque to the opposite wheel which perhaps has
better traction.
[0003] An antilock braking system or a traction control system for
a vehicle thus requires speed sensors to monitor the rotation of
some, if not all, of the wheels on the vehicle, and while a variety
of locations exist on a vehicle for installation of a speed sensor
for a wheel, perhaps the best is in the housing that contains the
bearing on which the wheel--or more accurately, the hub for the
wheel--rotates. This keeps much of the sensor isolated from
contaminants and objects that might otherwise damage it or disrupt
its operation. In this regard, the typical sensor of this type fits
into a cylindrical hole in the housing and has a stationary probe
which is presented toward a target wheel that rotates with the road
wheel and contains discontinuities, such as teeth, which the sensor
detects as the target wheel revolves. The result is a pulsating
signal which reflects the angular velocity of the wheel. A control
system monitors the signals from the wheels and initiates braking
to achieve the results desired. The spacing between a probe and its
target wheel has a significant affect on the operation of the
sensor, and it should not vary significantly from the optimum. But
many sensors of current manufacture that are installed in housing
holes leave much to be desired in this regard.
[0004] More specifically, the diameter of the through hole that
receives the typical sensor exceeds the diameter of the sensor by a
good measure, an as a consequence the sensor is not confined to a
fixed radial position in the hole. To be sure, the sensor is fitted
with an elastomeric O-ring, which establishes a seal between the
sensor and the wall of the hole and further serves to center the
sensor in the hole. But as a centering device the O-ring provides
little precision and further will enable the sensor to drift
laterally from the position it initially assumes. With many
active--as opposed to passive--sensors, the target wheel revolves
opposite a laterally presented face on the probe of the sensor, and
the size of the gap between the side face of the probe and the
target wheel is critical. It should remain constant and at an
optimum setting.
[0005] Aside from that, when a sensor is inserted off center into
its hole, a very real danger exists that the O-ring will be damaged
during the insertion. This may compromise the fluid barrier that
the O-ring normally provides and further can displace the sensor
from the center of the hole.
SUMMARY OF THE INVENTION
[0006] A sensor for installation in a hole in a housing to monitor
the rotation of a target wheel in the housing has a bushing and a
probe extended from the bushing into the housing where it has a
pickup area. An annular elastomeric element encircles the bushing
to position the bushing in the hole and a leading surface on the
bushing leads up to the elastomeric element to center the bushing
in a hole into which it is fitted. The invention also resides in
the sensor installed in the housing where the pickup area on its
probe is presented toward the target wheel. The housing may contain
a bearing, in which event the target wheel rotates with a hub
spindle that extends into the housing.
DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a longitudinal sectional view of a hub assembly
provided with an active sensor constructed in accordance with and
embodying the present invention;
[0008] FIG. 2 is an exploded view of the hub assembly and sensor,
with the former being in section;
[0009] FIG. 3 is an enlarged fragmentary view of the region of the
sensor enclosed within the dotted circle 3 of FIG. 2;
[0010] FIG. 4 is a longitudinal sectional view of a hub assembly
with a passive sensor constructed in accordance with and embodying
the present invention; and
[0011] FIG. 5 is an enlarged fragmentary view of the sensor,
similar to FIG. 3, but illustrating a modified bushing.
DETAILED DESCRIPTION OF THE INVENTION
[0012] Referring now to the drawings, a hub assembly A (FIG. 1),
which mounts a road wheel (not shown) for a vehicle on the
suspension system of the vehicle, contains a sensor S which
produces an electrical signal that reflects the angular velocity of
the wheel. The sensor S forms part of an antilock brake system or a
traction control system or both, and the signal it produces is
analyzed by a controller which controls a braking force or action
applied to the wheel. The hub assembly A includes a hub 2, a
housing 4 that is generally located around the hub 2, and a bearing
6 which enables the hub 2 to rotate relative to the housing 4 about
an axis X of rotation with relatively little friction. The road
wheel and a brake rotor (not shown) are attached to the hub 2,
while the housing 4 is secured firmly against a component of the
vehicle suspension system, such as a steering knuckle (not shown).
Here the hub 2 may be coupled to a CV joint (not shown) that
delivers torque to the hub 2 and the wheel.
[0013] The hub 2 has (FIG. 1) flange 10 and a spindle 12 which are
joined together as an integral steel forging or casting, with the
spindle 12 projecting from one face of the flange 10. Radially
beyond the spindle 12 the flange 10 contains wheel studs 14 which
project axially from its other face. Lug nuts (not shown) thread
over the wheel studs 14 to fasten the brake rotor and road wheel to
the hub 2. The spindle 12 emerges from a shoulder 16 located along
the inside face of the flange 10, and provides a seat for the
bearing 6. At its opposite end the spindle 12 has an abutment which
retains the bearing 6 on the spindle, and that abutment may be a
formed end 18 which is directed outwardly as an integral part of
the spindle 12. International application PCT/GB 98/01823, filed
Jun. 22, 1998 and published Dec. 30, 1998 under International
Publication No. WO 98/58762, discloses a rotary forming process for
creating the formed end 18. The abutment at the end of the spindle
12 may also take the form of a nut threaded over the spindle 12 or
a snap ring engaged with the spindle 12.
[0014] The bearing 6 includes (FIG. 1) two inner races in the form
of an outboard cone 22 and an inboard cone 24 which fit around the
spindle 12 with interference fits and are captured between the
shoulder 16 and the formed end 18. Each cone 22 and 24 has a
tapered raceway 26 that is presented outwardly away from the axis X
and a thrust rib 28 located at the large end of its raceway 26 and
providing a back face 30 which is squared off with respect to the
axis X. At their opposite ends beyond the small diameter ends of
their raceways 26, the two cones 22 and 24 have axially directed
extensions 32. Indeed, the two cones 22 and 24 abut at the ends of
their extensions 32. On the other hand, the back face 28 of the
outboard cone 22 abuts the shoulder 16 on the flange 10, while the
back face 28 of the inboard cone 24 abuts the formed end 18. Thus,
the two cones 22 and 24 are captured between the shoulder 16 and
the formed end 18. The extension 32 for the outboard cone 22 is
longer than the extension 32 for the inboard cone 24 and provides a
cylindrical seat 34 which leads out to the end of the extension
32.
[0015] In addition to the cones 22 and 24, the bearing 6 includes
(FIG. 1) tapered rollers 40 arranged in two rows, there being a
separate row around each cone 22 and 24. Actually, the rollers 40
extend around the raceways 26 for the cones 22 and 24, with their
tapered side faces being along the raceways 26 and their large end
faces against the thrust ribs 28. The rollers 40 of each row are
essentially on apex, which means that the envelopes in which their
tapered side faces lie have their apices located at a common point
along the axis X. Each row of rollers 40 has a cage 42 to maintain
the proper spacing between the rollers 40 in that row.
[0016] The ring-like housing 4 surrounds the spindle 12 as well as
the two cones 22 and 24 and the two rows of rollers 40 (FIG. 1). It
forms part of the bearing 6 in that it has tapered raceways 44
which are presented inwardly toward the axis X. In that sense, the
housing 4 constitutes the outer race of the bearing 6. The raceways
44 on the housing 4 taper downwardly toward an intervening surface
46 which separates them and encircles the extensions 32 on the two
cones 22 and 24. Actually, the intervening surface 46 lies oblique
to the axis X, it being inclined generally in the same direction as
the inboard raceway 44. The rollers 40 likewise lie along the
raceways 44 of the housing 4, contacting the raceways 44 at their
tapered side faces. At their large ends, the raceways 44 open into
short counterbores 48 in which the thrust ribs 28 of the two cones
22 and 24 are located.
[0017] The housing 4 (FIG. 1) has a generally cylindrical exterior
surface 50 and a triangular or rectangular flange 52 which projects
radially from the surface 50 and generally surrounds the
intervening surface 46 that is within the interior of the housing
4. Along its flange 52, the housing 4 is secured firmly to the
suspension system component with bolts that engage threaded holes
53 in the lobes of the flange 52 or at least pass through the
lobes. Between its lobes the flange 52 lies quite close to the
cylindrical exterior surface 50 and between two of the lobes the
flange 52 has a beveled surface 54 (FIG. 2) which lies generally
parallel to the intervening surface 46 between the two raceways 44.
Here the housing 4 is provided with an inclined hole 56 which
extends from the beveled surface 54 inwardly to the intervening
surface 46 and opens out of both.
[0018] The hole 56, which is cylindrical, has an axis Y (FIGS. 1
and 2) that is perpendicular to the surfaces 46 and 54 and
intersects the axis X at an angle that may range between 84.degree.
and 86.degree. and preferably is 85.degree.. The hole 56 may be
reamed to provide it with a smooth cylindrical surface.
[0019] The counterbores 48 in the housing 4 contain (FIG. 1) seals
58 which establish dynamic fluid barriers at the ends of the
housing 4. These barriers isolate the rollers 40 and the raceways
26 and 44 from road contaminants, such as water, ice-melting sales
and dirt.
[0020] The inclined hole 56 in the housing 4 receives the speed
sensor S which monitors a target wheel 60 that is carried by the
outboard cone 22 and thus rotates with the cone 22 and the hub 2
(FIGS. 1 and 2). The target wheel 60 is pressed over the extension
32 on the cone 22 to a position offset from the axis Y of the hole
56, there being an interference fit between the wheel 60 and the
cylindrical seat 34 on the extension 32. The target wheel 60 has
discontinuities which take the form of teeth 62 which are presented
toward the rollers 40 of the inboard row, and are likewise offset
from axis Y.
[0021] The sensor S includes (FIG. 2) a body 66 having a head 68
and a smaller bushing 70 which projects from a shoulder 72 on the
head 68. The bushing 70 is generally cylindrical and establishes an
axis Z which should coincide with the axis Y of the hole 56 when
the bushing 70 is in the hole 56. In addition, the sensor S has a
probe 74 which projects from the bushing 70 into the interior of
the housing 4. The probe 74 has a pickup area 76 that is presented
laterally away from the axis Z and toward the teeth 62 of the
target wheel 60. Here the sensor S generates an electrical signal
which is transmitted to a controller on the vehicle through a wire
78 that leads from the head 68.
[0022] Considering the bushing 70 in more detail, it contains
(FIGS. 2 and 3) an annular groove 80 which opens radially out of it
and receives an elastomeric O-ring 82. Between the groove 80 and
the shoulder 72 of the head 68 is a trailing surface 84 of
cylindrical configuration. On the other side of the groove 80 is a
tapered leading surface 86 that possesses its greatest diameter at
the groove 80 and tapers inwardly from there. Beyond the tapered
surface 86, the bushing 70 has a stepped end 88 from which the
probe 74 projects. The diameter of the hole 56 into which the
bushing 70 fits exceeds the diameter of the trailing surface 84 on
the bushing 70 by between 0.006 and 0.014 in. and preferably by
about 0.007 in. On the other hand, the diameter of the hole 56
exceeds the greatest diameter of the tapered surface 86 by between
0.001 and 0.009 in. and preferably by about 0.002 in. Thus, the
differences in diameter between the diameter of the leading surface
86 and the diameter of the trailing surface 84 may range between
0.004 in. and 0.006 in. The smallest diameter on the tapered
surface 86 is no greater than the diameter of the trailing surface
84. The tapered surface 86 lies oblique to the axis Z. The O-ring
82 when fitted into the annular groove 80 bears against the base of
the groove 80 and when otherwise undistorted has an outside
diameter exceeding the diameter of the hole 56 by about 0.015 to
0.025 in. and preferably by about 0.020 in. The stepped end 88 lies
inwardly from the smallest diameter on the tapered surface 86.
[0023] To assemble the hub assembly A, the target wheel 60 is
pressed over the extension 32 of the outboard-cone 22 before the
cone 22 is installed in the housing 4, although not to its final
position. Then the outboard cone 22 with its complement of rollers
40 is inserted with the housing 4 such that the rollers 40 of the
outboard row seat against the raceway 26 of the outboard cone 22
and against the outboard raceway 44 of the housing 4. At this
juncture, the target wheel 60 is pressed still farther over the
extension 32 of the outboard cone 22 until a prescribed spacing
exists between its teeth 96 and the axis Y of the inclined hole 56
in the housing 4. Thereupon, the inboard cone 24, with its
complement of rollers 40, is inserted into the housing 4.
Thereafter, the two cones 22 and 24 are passed over the spindle 12
of the hub 2 with the housing 4 captured between the two rows of
rollers 40 on the cones 22 and 24. Thereupon, the end of the
spindle 12 is upset to produce the formed end 18. The extensions 32
on the two cones 22 and 24 abut, and their lengths are such that a
slight preload exists in the bearing 6.
[0024] Once the hub 2, housing 4 and bearing 6 are all assembled
and united, the sensor S is installed in the housing 4. To this end
the probe 74 of the sensor S is aligned with the inclined hole 56
in the housing 4 and advanced to the hole 56. After a short
distance, the beveled surface 86 at the distal end of the bushing
70 encounters the outer edge of the hole 56, and as the advance
continues, the beveled surface 86 deflects the probe 74 toward a
centered position in the hole 56--a position in which the axes Y
and Z of the hole 56 and sensor body 66, respectively, are quite
close, if not aligned. This brings the O-ring 82 into a generally
centered position with respect to the hole 56, and with continued
advancement of the bushing 70, the O-ring 82 contracts radially and
enters the hole 56. Since the O-ring 82 is centered with respect to
the hole 56 when it enters the hole 56, it deforms uniformly around
its periphery and is less likely to be damaged than if it were off
center. The advancement continues with the O-ring 82 sliding along
the surface of the hole 56 until the shoulder 72 on the head 68
comes against beveled surface 54 on the flange 52 of the housing 4.
The O-ring 82 establishes a fluid barrier between the surface of
the hole 56 and the bushing 70 and prevents contaminants such as
water, ice-melting chemicals and dust and dirt from entering the
interior of the housing 4.
[0025] While the O-ring 82 determines the radial position of the
bushing 70 in the hole 56, that radial position cannot deviate more
than one-half the difference between the diameter of the hole 56
and the maximum diameter of the tapered surface 86 on the bushing
70. This is significantly less than one-half the difference between
the diameter of the hole 56 and the diameter of the trailing
surface 84, which is the latitude available with conventional
arrangements. Since the tapered surface 86 limits the deviation
between the axis Y of the hole 56 and the axis Z of the bushing 70,
the position of the pickup area 76 on the probe 74 relative to the
target wheel 60 falls within much closer tolerances. Basically, the
pickup area 76 of the probe 74 will not deviate from its ideal
position more then one-half the distance between the diameter of
the hole 56 and the maximum diameter of the tapered surface 86.
With an active sensor, as is the sensor S, the distance between the
pick up area 76 on the probe 74 and the teeth 62 of the target
wheel 60 is important and must remain within prescribed tolerances
for the sensor S to operate effectively.
[0026] Aside from protecting the O-ring 82 during the installation
of the sensor S and reducing the maximum deviation of the probe 74
from an ideal position, the tapered surface 86 on the bushing 70
enables the O-ring 82 to provide a more reliable seal between the
bushing 70 and the surface of the hole 56. It further facilitates
installation of the bushing 70 into the hole 56.
[0027] During the operation of the bearing assembly A, the hub 2
rotates with the road wheel. Since the two cones 22 and 24 are
pressed over the spindle 12 of the hub 2, they also rotate as does
the target wheel 60 which is pressed over the extension 32 of the
outboard cone 22. As the teeth 62 of the target wheel 60 move past
the pickup area 76 on the probe 74, they disrupt a magnetic field
and cause the sensor S to produce a pulsating electrical signal,
the frequency of which reflects the angular velocity of the hub
2.
[0028] A modified sensor T (FIG. 4) resembles the sensor S in that
its body 66 externally does not differ from the body 66 of the
sensor S, although it has a probe 90, which renders the sensor T
more suitable as the passive variety than as the active variety.
The probe 90 has a pickup area 92 at its end where it is presented
toward the axis X, actually at an angle which corresponds to the
angle of the beveled surface 54. The pickup area 92 of the probe 90
lies opposite a modified target wheel 94 having teeth 96 that are
preferably inclined at the angle of the pickup area 92. The target
wheel 94 is pressed over the extension 32 on the inboard cone 24
which, to accommodate the target wheel 94, is longer then the
extension 32 on the outboard cone 22.
[0029] In lieu of a tapered leading surface 86, on its bushing 70,
either one of the sensors S and T may have a cylindrical leading
surface 98 (FIG. 5), the diameter of which is between 0.001 and
0.009 in. and preferably 0.002 in. less than the diameter of the
hole 56. Other than that, the bushing 70 with the cylindrical
surface 98 and the bushing 70 with the tapered surface 86 are the
same and are used with the same O-ring 82 and in the same hole
56.
[0030] The raceways 44 of the housing 4 may be on separate outer
races or cups that are in the housing 4 or on a single race or
double cup in the housing 4. Moreover, the outboard cone 22 may be
formed as an integral part of the spindle 12. Apart from that, the
cones 22 and 24 may be retained on the spindle 12 by means other
than the formed end 18--for example, a nut threaded over the
spindle 12 or a snap ring fitted to it. Also the discontinuities in
the target wheels 60 and 94 may take forms other than the teeth 62
and 96. For example, they may be alternate north and south poles
along the wheels 60 and 94.
[0031] The sensors S and T and their respective target wheels 60
and 94 have utility beyond hub assemblies and antilock braking
systems or traction control systems. Indeed, the sensors S and T
may be used in any housing that contains a hole, similar to the
hole 56, which opens toward a rotating member that carries a target
wheel.
* * * * *