U.S. patent application number 15/408587 was filed with the patent office on 2017-05-04 for magnetic sensor packaging for transmissions.
This patent application is currently assigned to Ford Global Technologies, LLC. The applicant listed for this patent is Ford Global Technologies, LLC. Invention is credited to Mark Richard Dobson, Yuji Fujii, Nimrod Kapas, Joseph F. Kucharski, Gregory Michael Pietron, Diana Yanakiev.
Application Number | 20170122821 15/408587 |
Document ID | / |
Family ID | 51264113 |
Filed Date | 2017-05-04 |
United States Patent
Application |
20170122821 |
Kind Code |
A1 |
Pietron; Gregory Michael ;
et al. |
May 4, 2017 |
Magnetic Sensor Packaging for Transmissions
Abstract
Designs to package a magneto-elastic torque sensor in an
automotive transmission for volume production applications are
provided. A transfer case assembly includes a transfer case shaft
having a magnetized region and a magnetic torque sensor, for
detecting torque of the transfer case shaft, mounted on at least
one bushing supporting the transfer case shaft. A drive axle
assembly includes an axle housing, an input shaft having a
magnetized region, and a magnetic torque sensor, for detecting
torque of the input shaft, mounted to the axle housing.
Inventors: |
Pietron; Gregory Michael;
(Canton, MI) ; Kucharski; Joseph F.; (Livonia,
MI) ; Kapas; Nimrod; (Canton, MI) ; Yanakiev;
Diana; (Birmingham, MI) ; Dobson; Mark Richard;
(Howell, MI) ; Fujii; Yuji; (Ann Arbor,
MI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Ford Global Technologies, LLC |
Dearborn |
MI |
US |
|
|
Assignee: |
Ford Global Technologies,
LLC
Dearborn
MI
|
Family ID: |
51264113 |
Appl. No.: |
15/408587 |
Filed: |
January 18, 2017 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
15016654 |
Feb 5, 2016 |
|
|
|
15408587 |
|
|
|
|
13771258 |
Feb 20, 2013 |
9285282 |
|
|
15016654 |
|
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F16H 3/091 20130101;
B60Y 2400/307 20130101; G01L 3/101 20130101; B60K 25/06 20130101;
B60K 17/28 20130101; B60K 17/344 20130101 |
International
Class: |
G01L 3/10 20060101
G01L003/10; B60K 25/06 20060101 B60K025/06; B60K 17/28 20060101
B60K017/28; B60K 17/344 20060101 B60K017/344; F16H 3/091 20060101
F16H003/091 |
Claims
1. A transfer case assembly comprising: a transfer case shaft
having a magnetized region; and a magnetic torque sensor, for
detecting torque of the transfer case shaft, mounted on at least
one bushing supporting the transfer case shaft.
2. The assembly of claim 1 further comprising: a transfer case;
wherein the sensor is further mounted to the transfer case.
3. The assembly of claim 1 further comprising: an anti-rotation
device connected to the sensor and configured to prevent rotation
of the sensor in response to the transfer case shaft rotating.
4. The assembly of claim 1 wherein: the transfer case shaft
includes one of a transfer case input shaft, a transfer case output
shaft to rear wheels, a transfer case output shaft to front wheels,
and a transfer case output shaft to power takeoff.
5. The assembly of claim 1 wherein: the sensor includes a sensor
housing, wherein the sensor housing includes a channel running
therethrough for conveying lubrication to areas adjacent the
sensor.
6. A transmission comprising: a transmission case; a gear having a
magnetized region, wherein the gear is one of an idler gear and a
transfer gear; and a magnetic torque sensor, for detecting torque
transmitted by the gear, mounted to the transmission case.
7. The transmission of claim 6 wherein: the gear includes a
plurality of pieces which together form the gear, wherein one of
the pieces includes the magnetized region.
8. A transmission comprising: a transmission case; an idler shaft;
an idler gear and a transfer gear spaced apart from one another
about different portions of the idler shaft; wherein the idler
shaft includes a magnetized region in a space between the idler
gear and the transfer gear; and a magnetic torque sensor, for
detecting torque of the idler shaft, mounted on the transmission
case adjacent to the magnetized region.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of U.S. application Ser.
No. 15/016,654, filed Feb. 5, 2016, now U.S. Pat. No. ______; which
is a divisional of U.S. application Ser. No. 13/771,258, filed Feb.
20, 2013, now U.S. Pat. No. 9,285,282; the disclosures of which are
hereby incorporated in its entirety by reference herein.
TECHNICAL FIELD
[0002] The present invention relates to automatic transmissions
having magnetic sensors.
BACKGROUND
[0003] An automatic transmission of a vehicle includes an input
shaft and an output shaft. The input shaft receives an input torque
at an input speed from power derived from a power source such as an
engine. The transmission converts the input torque at the input
speed to an output torque at an output speed. The output shaft
transmits the output torque at the output speed to traction wheels
of the vehicle in order to propel the vehicle.
[0004] The transmission converts the input torque at the input
speed to the output torque at the output speed by adjusting a gear
ratio (for example, during an up-shift or down-shift) between the
input and output shafts. The transmission shifting is accomplished
by applying and/or releasing friction elements (such as clutches,
band-brakes, etc.) to change speed and torque relationships by
altering planetary gear configurations of the transmission. As a
result, power flow paths are established and disestablished from
the engine to the wheels.
[0005] The friction elements must be properly controlled in order
to satisfactorily shift the transmission. To this end, information
regarding the operation of the transmission is used to control the
friction elements. For instance, information indicative of the
input torque received by the input shaft and the speed of the input
shaft and information such as vehicle speed and throttle opening
may be used. Similarly, information indicative of the output torque
transmitted by the output shaft and the speed of the output shaft
may be used.
[0006] Torque and speed of the input shaft and the output shaft are
typically estimated based on various type of available information.
One way to avoid estimation is to use a magnetic sensor mounted
within the transmission to directly detect the torque and/or speed
parameters. However, installation and packaging of such magnetic
sensors within limited spaces of the transmission may provide a
challenge.
SUMMARY
[0007] Embodiments of the present invention are directed to designs
for packaging magnetic sensors such as magneto-elastic torque
sensors in automatic transmissions for volume production.
[0008] In one embodiment, the present invention provides a
transmission having an output shaft and a magnetic torque sensor.
The output shaft has a magnetized region. The sensor, for detecting
torque of the output shaft, is mounted on at least one friction
reduction member such as a bushing supporting the output shaft.
[0009] In one embodiment, the present invention provides a
transmission having a transmission case, an output shaft, and a
magnetic torque sensor. The output shaft has a magnetized region.
The sensor, for detecting torque of the output shaft, is mounted to
the transmission case.
[0010] In one embodiment, the present invention provides a
transmission including a stator tube and a magnetic torque sensor.
The stator tube encompasses an input shaft having a magnetized
region. The stator tube has a window adjacent the magnetized
region. The sensor, for detecting torque of the input shaft, is
positioned within the window and affixed to the stator tube to be
adjacent the magnetized region.
[0011] In one embodiment, the present invention provides a
transmission including a transmission case, a gear having a
magnetized region, and a magnetic torque sensor. The gear is one of
an idler gear and a transfer gear. The sensor, for detecting torque
of the output shaft, is mounted to the transmission case.
[0012] In one embodiment, the present invention provides a
transmission including a transmission case, a hollow idler shaft
having a magnetized region on an inner surface thereof, and a
magnetic torque sensor. The sensor, for detecting torque of the
idler shaft, is positioned within the idler shaft and mounted to
the transmission case.
[0013] In one embodiment, the present invention provides a
transmission including a transmission case, a differential drive
carrier having a magnetized region, and a magnetic torque sensor.
The sensor, for detecting torque of the driver carrier, is mounted
to the transmission case.
[0014] In one embodiment, the present invention provides a
transmission including a transmission case, at least one half-shaft
having a magnetized region, and a magnetic torque sensor. The
sensor, for detecting torque of the at least one half-shaft, is
mounted on the transmission case.
[0015] In one embodiment, the present invention provides a
transmission including a transmission case, an idler shaft, an
idler gear, a transfer gear, and a magnetic torque sensor. The
gears are spaced apart from one another about different portions of
the idler shaft. The idler shaft includes a magnetized region in
the space between the idler gear and the transfer gear. The sensor,
for detecting torque of the idler shaft, is mounted on the
transmission case adjacent to the magnetized region.
[0016] In one embodiment, the present invention provides a transfer
case assembly. The assembly includes a transfer case shaft and a
magnetic torque sensor. The transfer case shaft has a magnetized
region. The sensor, for detecting torque of the transfer case
shaft, is mounted on at least one friction reduction member such as
a bushing supporting the transfer case shaft.
[0017] In one embodiment, the present invention provides a
rear-wheel drive axle assembly having a rear-axle housing, an input
shaft having a magnetized region, and a magnetic torque sensor. The
sensor, for detecting torque of the input shaft, is mounted to the
rear-axle housing.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1 illustrates a block diagram of a vehicle powertrain
in accordance with embodiments of the present invention;
[0019] FIG. 2 illustrates a cross-sectional view of the torque
converter and the transmission of the powertrain shown in FIG. 1 in
which the transmission lacks both of an input shaft sensor and an
output shaft sensor;
[0020] FIGS. 3A, 3B, and 3C illustrate an example of a magnetic
torque sensor for detecting torque of a shaft;
[0021] FIG. 4 illustrates an example of a magnetic speed sensor for
detecting rotating speed of a shaft;
[0022] FIG. 5 illustrates a cross-sectional view of an automatic
transmission having an output shaft mounted magnetic torque sensor
packaging design in accordance with an embodiment of the present
invention;
[0023] FIG. 6 illustrates a cross-sectional view of an automatic
transmission having a case-mounted with press fit magnetic torque
sensor packaging design in accordance with an embodiment of the
present invention;
[0024] FIG. 7 illustrates a cross-sectional view of the input shaft
area of a front wheel drive transmission in which the input shaft
area lacks a magnetic torque sensor;
[0025] FIG. 8 illustrates a cross-sectional view of the input shaft
area of the transmission shown in FIG. 7 having an input shaft
magnetic torque sensor packaging design in accordance with an
embodiment of the present invention;
[0026] FIG. 9 illustrates a cross-sectional view of the output
shaft area of the transmission shown in FIG. 7 in which the output
shaft area lacks a magnetic torque sensor;
[0027] FIG. 10 illustrates a cross-sectional view of the output
shaft area of the transmission shown in FIG. 7 having an idler gear
magnetic torque sensor packaging design in accordance with an
embodiment of the present invention;
[0028] FIG. 11 illustrates a cross-sectional view of the output
shaft area of the transmission shown in FIG. 7 having an idler gear
shaft magnetic torque sensor packaging design in accordance with an
embodiment of the present invention;
[0029] FIG. 12 illustrates a cross-sectional view of the output
shaft area of the transmission shown in FIG. 7 having a
differential hub magnetic torque sensor packaging design in
accordance with an embodiment of the present invention;
[0030] FIG. 13 illustrates a cross-sectional view of the output
shaft area of the transmission shown in FIG. 7 having a half-shaft
magnetic torque sensor packaging design in accordance with an
embodiment of the present invention;
[0031] FIG. 14 illustrates a cross-sectional view of the input
shaft area of another front wheel drive transmission in which the
input shaft area lacks a magnetic torque sensor;
[0032] FIG. 15 illustrates a cross-sectional view of the input
shaft area of the transmission shown in FIG. 14 having an input
shaft magnetic torque sensor packaging design in accordance with an
embodiment of the present invention;
[0033] FIG. 16 illustrates a cross-sectional view of a rear wheel
drive transfer case with all-wheel drive (AWD) in which the
transfer case lacks a magnetic torque sensor;
[0034] FIG. 17 illustrates a cross-sectional view of the transfer
case shown in FIG. 16 having a shaft-mounted magnetic torque sensor
packaging design in accordance with an embodiment of the present
invention;
[0035] FIG. 18 illustrates a cross-sectional view of the transfer
case shown in FIG. 16 having a case-mounted magnetic torque sensor
packaging design in accordance with an embodiment of the present
invention; and
[0036] FIG. 19A illustrates a cross-sectional view of a magnetic
torque sensor packaging design in a rear-wheel drive (RWD) axle in
accordance with an embodiment of the present invention;
[0037] FIG. 19B illustrates an enlarged view of the encircled
portion of FIG. 19A.
DETAILED DESCRIPTION
[0038] Detailed embodiments of the present invention are disclosed
herein; however, it is to be understood that the disclosed
embodiments are merely exemplary of the invention that may be
embodied in various and alternative forms. The figures are not
necessarily to scale; some features may be exaggerated or minimized
to show details of particular components. Therefore, specific
structural and functional details disclosed herein are not to be
interpreted as limiting, but merely as a representative basis for
teaching one skilled in the art to variously employ the present
invention.
[0039] Referring now to FIG. 1, a block diagram of a vehicle
powertrain 10 in accordance with embodiments of the present
invention is shown. Powertrain 10 includes an engine 12, a torque
converter 14, and an automatic transmission 16. Transmission 16 has
an input shaft 18 and an output shaft 20. Engine 12 delivers torque
to torque converter 14 via crankshaft 13 of engine 12 which is
connected to torque converter 14. Torque converter 14 converts the
engine torque into an input torque at an input speed and transmits
the input torque at the input speed to input shaft 18 of
transmission 16. Transmission 16 serves to change a transmission
ratio and thus changes the input torque at the input speed into an
output torque (for example, increased torque) at an output speed
(for example, reduced speed). Transmission 16 transmits the output
torque at the output speed to output shaft 20. Output shaft 20 is
connected to a vehicle driveline (not shown) such that the output
torque at the output speed may be used to drive wheels of the
vehicle.
[0040] While not shown herein, embodiments of the present invention
can be used as well in a hybrid powertrain that includes, for
example, an engine and an electric motor without a torque
converter.
[0041] Powertrain 10 further includes at least one of an input
shaft sensor 22 and an output shaft sensor 24. Input shaft sensor
22 is associated with input shaft 18 and is configured to monitor
at least one of (input) torque and (input) speed of input shaft 18.
Similarly, output shaft sensor 24 is associated with output shaft
20 and is configured to monitor at least one of (output) torque and
(output) speed of output shaft 20. Sensors 22 and 24 provide sensor
signals indicative of the monitored information to a controller
(not shown) for the controller to control operation of transmission
16 accordingly.
[0042] Referring now to FIG. 2, with continual reference to FIG. 1,
a cross-sectional view of torque converter 14 and transmission 16
is shown. As shown in FIG. 2, torque converter 14 is encased within
a torque converter case 26 and transmission 16 is encased within a
transmission case 28.
[0043] Transmission mechanism 30 changes the input torque at the
input speed received by input shaft 18 into an output torque at an
output speed transmitted by output shaft 20. As illustrated in the
right-hand side of FIG. 2, transmission mechanism 30 uses planetary
gear sets. Embodiments of the present invention may be applied to
other types of transmission mechanisms including, but not limited
to, belt-drive transmissions, dual clutch transmissions, or
continuously variable transmissions.
[0044] Torque converter 14 includes a turbine 32, a stator 34, and
an impeller 36. Impeller 36 is fixedly connected to engine
crankshaft 13 such that impeller 36 rotates as crankshaft 13
rotates. Stator 34 is fixed onto the stator shaft (i.e., the stator
tube) of a stator support 40 via a one-way clutch 39. Stator
support 40 is fixed to transmission case 28. Turbine 32 is
mechanically linked via a turbine hub 42 to input shaft 18.
[0045] Notably, transmission 16, as shown in FIG. 2, does not have
either an input shaft sensor 22 for directly measuring torque
and/or speed of input shaft 18 or an output shaft sensor 24 for
directly measuring torque and/or speed of output shaft 20.
[0046] In accordance with embodiments of the present invention, a
transmission is configured with inventive design concepts and
features for enabling the packaging of an input shaft sensor 22
and/or an output shaft sensor 24 within the transmission in which
sensors 22 and 24 are magnetic sensors. The packaging of an input
shaft sensor 22 within a transmission in accordance with
embodiments of the present invention enables direct measurement of
torque and/or speed of input shaft 18. Similarly, the packaging of
an output shaft sensor 24 within a transmission in accordance with
embodiments of the present invention enables direct measurement of
torque and/or speed of output shaft 20.
[0047] In some embodiments, sensors 22 and 24 are magnetic torque
sensors for monitoring torque of input and output shafts 18 and 20,
respectively. Similarly, in some embodiments, sensors 22 and 24 are
magnetic speed sensors for monitoring speed of shafts 18 and 20,
respectively. Further, in some embodiments, sensors 22 and 24 are
magnetic torque and speed sensors for monitoring torque and speed
of shafts 18 and 20, respectively.
[0048] Magnetic torque and speed sensor technology operates
optimally with a free smooth surface area on a shaft with constant
diameter and controlled hardness, wherein a part of the shaft is
magnetized. The magnetic sensor technology makes use of magnetic
flux sensing elements such as fluxgate sensors. The sensing
elements are preferably stationary and fixed with respect to the
rotating magnetized surface of the shaft. Translation of the shaft
in either the axial or radial direction relative to the sensor
housing is preferably minimized. As indicated above, conventional
transmission designs, such as shown in FIG. 2, may represent a
challenge for packaging of magnetic sensors.
[0049] Sensors 22 and 24 may be magneto-elastic sensors as
described in U.S. Pat. Nos. 6,145,387; 6,047,605; 6,553,847; and
6,490,934. Other magnetic sensors may also be used to enable
accurate measurements of torque exerted onto a rotating shaft and
rotating speed of the shaft without physical contact between a
magnetic flux sensing element of the sensor and the shaft.
[0050] Referring now to FIGS. 3A, 3B, and 3C, an example of a
magnetic torque sensor for detecting torque of a shaft will be
described. This example assumes that the shaft is input shaft 18
and that the magnetic torque sensor is input shaft sensor 22.
[0051] Input shaft sensor 22 includes a magnetic flux sensing
element(s) within a sensor housing 44. Input shaft 18 includes a
magnetized region 46. Magnetized region 46 circumferentially
extends around input shaft 18. Magnetized region 46 may be created
by coating magnetized material as a thin layer on a chosen region
of input shaft 18 or by magnetizing a region on the shaft. Sensor
housing 44 is fixed in position adjacent to the magnetized region
46 of input shaft 18 to enable the sensing element to sense the
torque induced signal.
[0052] Preferably, shaft 18 is made of steel having high Nickel
content, preferably with Martensite structure at the surface layer.
Shaft 18 is hardened to enable permanent magnetization. The chosen
magnetized region 46 of shaft 18 is magnetized with magnetized
material thereon to a designed depth from the surface within the
hardened layer. A magnetic pattern or polarity signature may depend
on a certain implementation of magneto-elastic torque sensing
principles. However, they require a magnetized region 46 of shaft
18 and a sensor housing 44 that contains one or more magnetic flux
sensing elements. Sensor housing 44 may include other types of
sensing elements such as thermo-couples.
[0053] At no load (FIG. 3A), magnetic flux 47 is contained near or
within the shaft surface. The illustration in FIG. 3A shows a
simplified view of flux direction. Depending on chosen
magnetization patterns, magnetic flux may have more complex
directional patterns.
[0054] When load is applied (i.e., input shaft 18 is twisted),
magnetic flux 47 extends from the shaft surface and its axial
component which is proportional to the applied torque is measured
by the sensing element (FIGS. 3B and 3C). For instance, as shown in
FIGS. 3B and 3C, magnetic flux 47 is realigned in one direction
when the load is greater than zero and is realigned in the opposite
direction when the load is less than zero. Either realignment
causes more magnetic flux 47 to come out from the shaft surface in
proportion to the load level. As indicated in FIGS. 3B and 3C, the
sensing element detects the magnetic flux direction and intensity.
Variations of this technology may include, for example, dual band
and tri-band magneto-elastic torque sensors.
[0055] Referring now to FIG. 4, an example of a magnetic speed
sensor for detecting rotating speed of a shaft will be described.
Again, this example assumes that the shaft is input shaft 18 and
that the magnetic speed sensor is input shaft sensor 22. Input
shaft sensor 22 includes sensor housing 44 having magnetic flux
sensing element(s). Input shaft 18 includes a magnetized region 48
comprised of magnetic material placed in spots repeatedly around
the circumference of input shaft 18 as shown in FIG. 4. Sensor
housing 44 is placed near the shaft surface, picking up the
circumferential component of magnetic flux. A periodic voltage
signal is generated on a magnetic spot as the rotating shaft 18
passes by the sensing element. The periodic voltage signal can be
converted into a square wave signal using a comparator circuit
which can then be converted into rpm by counting the number of
square wave periods. Variations of this technology may include, for
example, single band and dual band speed sensors.
[0056] For simplicity, a magnetic torque and/or speed sensor is
referred to herein as a "magnetic torque sensor" or simply
"sensor". However, as described above, such a magnetic torque
sensor or sensor may be a magnetic torque sensor only, a magnetic
speed sensor only, or a magnetic torque and speed sensor.
[0057] With the foregoing description in mind, various embodiments
of the present invention will now be described.
[0058] With reference to FIGS. 5 and 6, embodiments of the present
invention provide unique packaging layouts of a magnetic torque
sensor for the output shaft of a transmission.
[0059] Referring now to FIG. 5, a cross-sectional view of an
automatic transmission 50 having an output shaft mounted magnetic
torque sensor packaging design in accordance with an embodiment of
the present invention is shown. General features of this design
include sensor 24 being supported by friction reduction members
such as bearings or bushings to maintain a fixed distance between
sensing element 44 of sensor 24 and output shaft 20. The axial and
radial alignment of sensor 24 is insensitive to relative motion
between output shaft 20 and transmission case 28. An additional
axial length is used for the bearings and an anti-rotation device
is included.
[0060] Particular features, as shown in FIG. 5, of this design
include the following. The housing of sensor 24 is mounted on
bearings or bushings supporting output shaft 20 as indicated at 51.
An anti-rotation device for the housing of sensor 24 can be
positioned in several ways. In one way, as indicated at 52, a slot
is cut into transmission case 28 and a key is molded to the outside
of the sensor housing. A snap ring ensures axial location of sensor
24 relative to output shaft 20 as indicated at 53. The relative
diameters of the bearings, sensor 24, the anti-rotation device, and
a seal ensure assembly-feasibility as indicated at 54. Sensor 24 is
protected from dust since it is sitting inboard of the seal as
indicated at 55. A lubrication hole ensures wetting of sensory
surface on output shaft 20 and provides passage to lubricate other
components (bearing, seal) as indicated at 56. Wiring of sensor 24
is routed internally through transmission case 28 to a common power
and control bus (not shown) as indicated at 57a. Alternatively,
wiring of sensor 24 is routed externally through a seal, preferably
near the top of transmission case 28, as indicated at 57b. A common
transmission case 28, sensor housing, and snap ring can be used for
both 4.times.4 and 4.times.2 versions as indicated at 58 (4.times.4
version shown above centerline and 4.times.2 version shown below
centerline).
[0061] Referring now to FIG. 6, a cross-sectional view of an
automatic transmission 60 having a case-mounted with press fit
magnetic torque sensor packaging design in accordance with an
embodiment of the present invention is shown. General features of
this design include the following. The sensor housing functions as
an anti-rotation device and there is no need for sensor bearings of
bushings.
[0062] Particular features, as shown in FIG. 6, of the design
include the following. The sensor housing is mounted to
transmission case 28 by press fit as indicated at 61. As such, the
press-fitted sensor housing functions as an anti-rotation device
and a snap ring for axial positioning of sensor 24 is not required.
The relative diameters of the bearings, sensor 24, and the seal
ensure assembly-feasibility as indicated at 62. Sensor 24 is
protected from dust since it is sitting inboard of the seal (in
both 4.times.2 and 4.times.4 versions) as indicated at 63. In the
4.times.4 version (above the centerline), the seal is integrated
into the sensor housing. A lubrication hole ensures wetting of
sensory surface on output shaft 20 and provides passage to
lubricate other components (bearing, seal) as indicated at 64.
Wiring of sensor 24 is routed internally through transmission case
28 to a common control bus as indicated at 65a. Alternatively,
wiring of sensor 24 is routed externally through a seal, preferably
near the top of transmission case 28 as indicated at 65b. A common
transmission case 28 and sensor housing can be used for both
4.times.4 and 4.times.2 versions as indicated at 66.
[0063] It is briefly noted that the principles of packaging designs
in accordance with embodiments of the present invention, as well as
the principles of other packaging designs described herein, can be
applied to various power-train components including the transfer
case, the engine crankshaft, the power take-off shaft, etc.
[0064] With reference to FIGS. 7 through 13, embodiments of the
present invention provide unique packaging layouts of magnetic
torque sensors for a front wheel drive transmission.
[0065] Referring now to FIG. 7, a cross-sectional view of the input
shaft area of a front wheel drive transmission 70 in which the
input shaft area lacks a magnetic torque sensor is shown. For
simplicity, the same reference numerals used above will be used for
like components of transmission 70 as is shown in FIG. 7 and as
modified in accordance with embodiments of the present invention as
described below.
[0066] Referring now to FIG. 8, a cross-sectional view of the input
shaft area of transmission 70 shown in FIG. 7 having an input shaft
magnetic torque sensor packaging design 90 in accordance with an
embodiment of the present invention is shown. As shown in FIG. 8,
features of design 90 include a shortened spline as indicated at
91. Slots are cut into stator support 40 and sleeve (at one and
seven o'clock positions) (six o'clock position is just for better
illustration) as indicated at 92. A fillet is provided to avoid
damaging the bushing as indicated at 93. The PC board enclosure of
a sensor 22 is fixed by screws as indicated at 94. The PC board
enclosure should not be leak-proof and should withstand 120 psi and
oil temperatures of 200 F to 250 F. The pressure blow off valve is
set at 165 psi and heavy towing can impinge 300 F. The ID of the
sleeve is changed to the same as the ID of stator support 40 as
indicated at 95. The sleeve is pressed in after the wiring of
sensor 22 is routed. A groove is milled circumferentially for the
wiring as indicated at 96. A groove is milled to feed the wiring
through the apply pressure port of torque converter 14 as indicated
at 97. Holes are drilled for the wiring at ten o'clock (twelve
o'clock position is just for better illustration) as indicated at
98. The wiring is glued and/or sealed in place as further indicated
at 98. Grooves are milled for the wiring as indicated at 99. The
wiring is routed to a connector at transmission case 28 as
indicated at 99a.
[0067] Referring now to FIG. 9, a cross-sectional view of the
output shaft area of transmission 70 shown in FIG. 7 in which the
output shaft area lacks a magnetic torque sensor is shown. As
indicated in FIG. 9, potential locations for a magnetic torque
sensor include: sensor at gear face (idler gear magnetic torque
sensor packaging design--FIG. 10) as indicated at 101; sensor on
shaft internal diameter (idler gear shaft magnetic torque sensor
packaging design--FIG. 11) as indicated at 102; sensor on
differential drive carrier (differential hub magnetic torque sensor
packaging design--FIG. 12) as indicated at 103; and sensor on
half-shaft (half-shaft magnetic torque sensor packaging
design--FIG. 13) as indicated at 104.
[0068] Referring now to FIG. 10, with continual reference to FIG.
9, a cross-sectional view of the output shaft area of transmission
70 shown in FIG. 7 having an idler gear magnetic torque sensor
packaging design 110 in accordance with an embodiment of the
present invention is shown. Features of design 110 include the
following. A portion of either an idler gear or a transfer gear is
magnetized on its surface to produce a magnetic sensing region as
indicated at 111. The sensing element of magnetic torque sensor 24
is mounted into transmission case 28 or bulkhead adjacent to the
magnetized surface of the idler gear as indicated at 112.
[0069] Referring now to FIG. 11, with continual reference to FIG.
9, a cross-sectional view of the output shaft area of transmission
70 shown in FIG. 7 having an idler gear shaft magnetic torque
sensor packaging design 120 in accordance with an embodiment of the
present invention is shown. Features of design 120 include the
following. The gear of the differential drive is flipped onto the
left side as indicated at 121 (for instance, compare with FIG. 9).
The gear of the idler shaft, the parking gear, and the bearing are
moved to the left as indicated at 122. The features indicated at
122 further include reducing the parking gear diameter and making a
corresponding minor change to transmission case 28. A portion of
the internal surface of the idler gear shaft is magnetized to
produce a magnetic sensing region as indicated at 123. The sensing
element of magnetic torque sensor 24 is mounted onto a sleeve
running through the internal diameter of the idler gear as
indicated at 124. Wiring of the sensing element is routed out
through the sleeve as indicated at 125.
[0070] With continual reference to FIG. 11, in another variation
the outer surface of a portion of the idler shaft between the
transfer shaft input gear and the transfer shaft output gear
includes a magnetized region. A sensor is mounted to the case
adjacent to the magnetized region to read the torque of the idler
shaft.
[0071] Referring now to FIG. 12, with continual reference to FIG.
9, a cross-sectional view of the output shaft area of transmission
70 shown in FIG. 7 having a differential hub magnetic torque sensor
packaging design 130 in accordance with an embodiment of the
present invention is shown. Features of design 130 include the
following. The surface of the differential drive carrier is
extended as indicated at 131. A portion of the carrier surface is
magnetized as indicated at 132. The sensing element of magnetic
torque sensor 24 is mounted onto transmission case 28 adjacent the
magnetized carrier surface as indicated at 133. Wiring of the
sensing element is routed out as indicated at 134. In another
embodiment, the sensing element of magnetic torque sensor 24 is
mounted onto transmission case 28 between the final drive (bevel)
gear and the side carrier pin shaft and adjacent the magnetized
carrier surface.
[0072] Referring now to FIG. 13, with continual reference to FIG.
9, a cross-sectional view of the output shaft area of transmission
70 shown in FIG. 7 having a half-shaft magnetic torque sensor
packaging design 140 in accordance with an embodiment of the
present invention is shown. Design 140 is for FWD only. Features of
design 140 include the following. The half-shaft and the associated
seal are moved axially away from the transmission in both
directions (i.e. to the left and to the right) as indicated at 141.
This requires a change to transmission case 28. The surfaces of
half-shafts are magnetized in the manner described above as
indicated at 142. The sensing elements of magnetic torque sensors
24 are mounted onto transmission case 28 adjacent the magnetized
surfaces of the half-shafts, respectively, as indicated at 143.
Wiring of the sensing elements is routed out as indicated at
144.
[0073] With reference to FIGS. 14 and 15, an embodiment of the
present invention provides a unique packaging layout of a magnetic
torque sensor for input shaft of another front wheel drive
transmission.
[0074] Referring now to FIG. 14, a cross-sectional view of the
input shaft area of a front wheel drive transmission 140 in which
the input shaft area lacks a magnetic torque sensor is shown. For
simplicity, the same reference numerals used above will be used for
like components of transmission 140 as is shown in FIG. 14 and as
modified in accordance with an embodiment of the present invention
as described below.
[0075] Referring now to FIG. 15, a cross-sectional view of the
input shaft area of transmission 140 shown in FIG. 14 having an
input shaft magnetic torque sensor packaging design 160 in
accordance with an embodiment of the present invention is shown. In
transmission 140, stator assembly 40 is made of a stator support
and a stator tube which press-fit together to form stator assembly
40. The assembled stator assembly 40 is interconnected with a pump
assembly by bolts in this design. As shown in FIG. 15, features of
design 160 include the following. The outside diameter of input
shaft 18 is made straight as indicated at 161. Slots (windows) are
cut in stator support 40 for the PC board and enclosure of magnetic
torque sensor 22 as indicated at 162. A circumferential groove is
milled for the wiring of the sensing element of sensor 22 as
indicated at 163. An axial groove is milled for the wiring as
indicated at 164. A hole is drilled for the wiring and the wiring
is glued and/or sealed in place as indicated at 165. The wiring is
routed out of the transmission as indicated at 167.
[0076] With reference to FIGS. 16, 17, and 18, embodiments of the
present invention provide unique packaging layouts of magnetic
torque sensors for a rear wheel drive transfer case with all-wheel
drive (AWD).
[0077] Referring now to FIG. 16, a cross-sectional view of a rear
wheel drive transfer case 170 in which transfer case 170 lacks a
magnetic torque sensor is shown. For simplicity, the same reference
numerals used above will be used for like components of transfer
case 170 as is shown in FIG. 16 and as modified in accordance with
embodiments of the present invention as described below.
[0078] As indicated in FIG. 16, potential first and second
placement options for a magnetic torque sensor include: sensor on
the input shaft (large diameter, smooth outer surface) as indicated
at 171; and sensor on the output shaft (small diameter, sensor
linearity range may be reduced) as indicated at 172.
[0079] Referring now to FIG. 17, a cross-sectional view of transfer
case 170 shown in FIG. 16 having a shaft mounted magnetic torque
sensor packaging design 180 in accordance with an embodiment of the
present invention is shown. Design 180 includes the first and
second placement options indicated above.
[0080] Features of design 180 pursuant to the first option in which
a magnetic torque sensor 22 is on the input shaft include the
following. Splines are moved to the right (up to the pump's
shoulder) to gain more axial space for sensor 22 as indicated at
181. This modification is needed to both of the input and output
shafts. Sensor 22 is axially located at one end by a shoulder on
the input shaft as indicated at 182a. Sensor 22 is axially located
at the other end by a snap ring as indicated at 183a. The housing
of sensor 22 is supported by bearings as indicated at 184a. An
anti-rotation finger is provided as indicated at 185a. Wiring of
the sensing element of sensor 22 is routed out through a standard
connector as indicated at 186a.
[0081] Features of design 180 pursuant to the second option in
which a magnetic torque sensor 24 is on the output shaft include
the following. The diameter of the output shaft is increased as
possible to avoid reduction in the linearity range of sensor 24 as
indicated at 187. Sensor 24 is axially located at one end by a
washer as indicated at 188. Sensor 24 is axially located at the
other end by a snap ring as indicated at 183b. The housing of
sensor 24 is supported by bearings as indicated at 184b. An
anti-rotation finger is provided as indicated at 185b. Wiring of
the sensing element of sensor 24 is routed out through a standard
connector as indicated at 186b. In either option, along with the
other embodiments described herein, magnetic shields can be
incorporated in the sensor housing.
[0082] Referring now to FIG. 18, a cross-sectional view of transfer
case 170 shown in FIG. 16 having a case-mounted magnetic torque
sensor packaging design 190 in accordance with an embodiment of the
present invention is shown. Design 190 also includes the first and
second options.
[0083] Features of design 190 pursuant to the first option in which
a magnetic torque sensor 22 is on the input shaft include the
following. Splines are moved to the right (up to the pump's
shoulder) to gain more axial space for sensor 22 as indicated at
191. This modification is needed to both of the input and output
shafts. The housing of sensor 22 is mounted to the transfer case
housing by screws as indicated at 192. This supports the sensor
housing axially and in a radial manner and functions as an
anti-rotation device. The wiring of the sensing element of sensor
22 is routed out through a standard connector as indicated at
193.
[0084] Features of design 190 pursuant to the second option in
which a magnetic torque sensor 24 is on the output shaft include
the following. The diameter of the output shaft is increased as
possible to avoid reduction in the linearity range of sensor 24 as
indicated at 194. The housing of sensor 24 is press fit into the
transfer case housing as indicated at 195. This supports the sensor
housing axially and in a radial manner and functions as an
anti-rotation device. The wiring of the sensing element of sensor
24 is routed out through a standard connector as indicated at 196.
Again, in either option, magnetic shields can be incorporated in
the sensor housing.
[0085] Referring now to FIG. 19A, a cross-sectional view of a
magnetic torque sensor packaging design 200 in a rear-wheel drive
(RWD) axle in accordance with an embodiment of the present
invention is shown. FIG. 19B illustrates an enlarged view of the
encircled portion of FIG. 19A.
[0086] As shown in FIG. 19B, modifications are made to an original
design indicated by 202 (top half of drawing) to produce the
inventive design indicated by 204 (bottom half of drawing). The
modifications to the original design include making the input shaft
diameter uniform, locating sensor 22, installing a sensor bobbin
indicated at 206. Installing the sensor bobbin includes providing a
lube hole indicated at 208 and incorporating a spacer indicated at
210 such that the sensor bobbin has anti-rotation capability. The
sensor bobbin is a slide-in housing which is press fitted. Contact
points with the housing are close to the outer race of bearings so
that radial movement relative to the shaft is minimized. The
modifications further include routing a wire from the sensor
bobbin. The wire includes a heavy duty cover for protection against
motion and possible damage due to mud, ice, etc. A connector is
attached to the other end of the wire as indicated at 212 for easy
installation and removal.
[0087] While exemplary embodiments are described above, it is not
intended that these embodiments describe all possible forms of the
invention. Rather, the words used in the specification are words of
description rather than limitation, and it is understood that
various changes may be made without departing from the spirit and
scope of the invention. Additionally, the features of various
implementing embodiments may be combined to form further
embodiments of the invention.
* * * * *