U.S. patent application number 14/511301 was filed with the patent office on 2016-04-14 for all-wheel drive driveline with disconnecting axle.
The applicant listed for this patent is American Axle & Manufacturing, Inc.. Invention is credited to Paul Joseph Valente.
Application Number | 20160101691 14/511301 |
Document ID | / |
Family ID | 55588837 |
Filed Date | 2016-04-14 |
United States Patent
Application |
20160101691 |
Kind Code |
A1 |
Valente; Paul Joseph |
April 14, 2016 |
ALL-WHEEL DRIVE DRIVELINE WITH DISCONNECTING AXLE
Abstract
A disconnecting driveline component can include a shaft coupled
to one of a pair of output members of a differential. A clutch
input can be coupled for rotation with one of a ring gear and the
one of the output members. A clutch output can be coupled for
rotation with one of a differential case and the shaft. A collar
can be axially-slidable between a first position, where the collar
couples the clutch input and the clutch output to transmit
rotational power therebetween, and a second position where the
collar is rotatably decoupled from one of the clutch input and the
clutch output. A pilot input can be non-rotatably coupled to the
clutch input. A pilot output can be fixed to the clutch output. An
electromagnet can draw the pilot input into frictional engagement
with the pilot output when the collar is in the second
position.
Inventors: |
Valente; Paul Joseph;
(Detroit, MI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
American Axle & Manufacturing, Inc. |
Detroit |
MI |
US |
|
|
Family ID: |
55588837 |
Appl. No.: |
14/511301 |
Filed: |
October 10, 2014 |
Current U.S.
Class: |
475/150 |
Current CPC
Class: |
B60K 2023/0858 20130101;
F16D 23/04 20130101; F16D 2023/0687 20130101; B60K 23/0808
20130101; F16H 48/34 20130101; F16D 27/112 20130101; B60K 17/3515
20130101; B60K 23/08 20130101; B60K 17/35 20130101; F16D 11/14
20130101; F16D 2011/004 20130101 |
International
Class: |
B60K 17/35 20060101
B60K017/35; F16D 27/112 20060101 F16D027/112; B60K 23/08 20060101
B60K023/08 |
Claims
1. A disconnecting driveline component comprising: a housing; an
input gear received in the housing; a ring gear received in the
housing and being meshingly engaged with the input gear to receive
power therefrom, the ring gear being rotatable about an axis; a
differential assembly received in the housing and including: a
differential case being coupled to the ring gear for common
rotation about the axis; and a differential gearset being coupled
to the differential case to receive rotary power therefrom, the
differential gearset having a pair of output members; a first shaft
coupled to one of the pair of output members for rotation therewith
about the axis; an axle shaft; a clutch device including: a first
clutch member being coupled to the first shaft for rotation
therewith about the axis; a second clutch member being coupled to
the axle shaft for rotation therewith about the axis; a carrier
being axially movably but non-rotatably coupled to the first clutch
member; and a collar being axially-slidably but non-rotatably
coupled to one of the carrier and the first clutch member for
movement along the axis between a first position, in which the
collar is coupled to the second clutch member to transmit
rotational power therebetween, and a second position in which the
collar is rotatably decoupled from the second clutch member; and a
pilot clutch device including: a pilot input member being
axially-slidably but non-rotatably coupled to the carrier; a pilot
output member being fixedly coupled to the second clutch member;
and a pilot actuator being selectively operable for moving the
pilot input member into frictional engagement with the pilot output
member.
2. The disconnecting driveline component of claim 1, wherein a
spring is disposed between the pilot input member and the carrier
and configured to bias the pilot input member away from the pilot
output member.
3. The disconnecting driveline component of claim 2, wherein the
pilot actuator includes an electromagnet selectively operable for
generating a magnetic field, the magnetic field configured to
overcome the spring and draw the pilot input member into frictional
engagement with the pilot output member.
4. The disconnecting driveline component of claim 1, wherein a
spring is disposed between the carrier and the collar and
configured to bias the collar toward the first position when the
collar is axially translated from the second position to the first
position.
5. The disconnecting driveline component of claim 1, wherein the
carrier comprises a plate member and a tubular member that is
fixedly coupled to the plate member, the plate member defining an
internally splined aperture that is engaged to an externally
splined portion of the first clutch member.
6. The disconnecting driveline component of claim 5, wherein the
collar is slidably received in the tubular member.
7. The disconnecting driveline component of claim 1, wherein the
clutch device further includes a clutch fork that is engaged to the
carrier to axially translate the carrier.
8. The disconnecting driveline component of claim 1, wherein the
pilot actuator includes an electromagnet fixedly coupled to the
housing.
9. A disconnecting driveline component comprising: a housing; an
input gear received in the housing; a ring gear received in the
housing and being meshingly engaged with the input gear to receive
power therefrom, the ring gear being rotatable about an axis; a
differential assembly received in the housing and including: a
differential case including a first case member, which is coupled
to the ring gear for common rotation about the axis, and a second
case member; and a differential gearset being coupled to the second
case member to receive rotary power therefrom, the differential
gearset having a pair of output members; a clutch device including:
a first clutch member being coupled to the first case member for
rotation therewith about the axis; a second clutch member being
coupled to the second case member for rotation therewith about the
axis; a carrier being axially movably but non-rotatably coupled to
the first clutch member; and a collar being axially-slidably but
non-rotatably coupled to one of the carrier and the first clutch
member for movement along the axis between a first position, in
which the collar is coupled to the second clutch member to transmit
rotational power therebetween, and a second position in which the
collar is rotatably decoupled from the second clutch member; and a
pilot clutch device including: a pilot input member being
axially-slidably but non-rotatably coupled to the carrier; a pilot
output member being fixedly coupled to the second clutch member;
and a pilot actuator being selectively operable for moving the
pilot input member into frictional engagement with the pilot output
member.
10. The disconnecting driveline component of claim 9, wherein a
spring is disposed between the pilot input member and the carrier
and configured to bias the pilot input member away from the pilot
output member.
11. The disconnecting driveline component of claim 10, wherein the
pilot actuator includes an electromagnet selectively operable for
generating a magnetic field, the magnetic field configured to
overcome the spring and draw the pilot input member into frictional
engagement with the pilot output member.
12. The disconnecting driveline component of claim 9, wherein a
spring is disposed between the carrier and the collar and
configured to bias the collar toward the first position when the
collar is axialy translated from the second position to the first
position.
13. The disconnecting driveline component of claim 9, wherein the
carrier comprises a plate member and a tubular member that is
fixedly coupled to the plate member, the plate member defining an
internally splined aperture that is engaged to an externally
splined portion of the first clutch member.
14. The disconnecting driveline component of claim 13, wherein the
collar is slidably received in the tubular member.
15. The disconnecting driveline component of claim 9, wherein the
second case member is supported for rotation within the housing
relative to the first case member.
16. The disconnecting driveline component of claim 9, wherein the
pilot actuator includes an electromagnet fixedly coupled to the
housing.
17. A disconnecting driveline component comprising: a housing; an
input gear received in the housing; a ring gear received in the
housing and meshingly engaged with the input gear to receive power
therefrom, the ring gear being rotatable about an axis; a
differential assembly received in the housing and including: a
differential case; and a differential gearset being coupled to the
differential case to receive rotary power therefrom, the
differential gearset having a pair of output members; a shaft
coupled to one of the pair of output members; a clutch device being
configured to selectively permit transmission of rotary power
between the ring gear and the shaft, the clutch device including: a
first clutch member coupled for common rotation with one of the
ring gear and the one of the pair of output members; a second
clutch member coupled for common rotation with one of the
differential case and the shaft; and a collar that is
axially-slidable along the axis between a first position, in which
the collar couples the first clutch member to the second clutch
member to transmit rotational power therebetween, and a second
position in which the collar is rotatably decoupled from one of the
first clutch member and the second clutch member; and a pilot
clutch device including: a pilot input member being axially
slidably but non-rotatably coupled to the first clutch member; a
pilot output member being fixed to the second clutch member; and an
electromagnet being selectively operable for generating a magnetic
field that draws the pilot input member into frictional engagement
with the pilot output member, the pilot clutch coupling the first
clutch member to the second clutch member when the pilot input
member frictionally engages the pilot output member and the collar
is in the second position.
18. The disconnecting driveline component of claim 17, wherein the
shaft is coupled for common rotation with the one of the pair of
output members when the collar is in the first and second
positions.
19. The disconnecting driveline component of claim 17, wherein the
shaft is rotatably decoupled from the one of the pair of output
members when the collar is in the second position, and is coupled
for common rotation with the one of the pair of output members when
the collar is in the first position.
20. The disconnecting driveline component of claim 17, wherein the
clutch device further includes a spring configured to bias the
collar toward the first position when the collar is axially
translated from the second position to the first position.
Description
FIELD
[0001] The present disclosure relates to all-wheel drive drivelines
with a disconnecting axle.
BACKGROUND
[0002] This section provides background information related to the
present disclosure which is not necessarily prior art.
[0003] Disconnecting all-wheel drive vehicles are known in the art
from various issued patents, such as U.S. Pat. No. 8,042,642 issued
Oct. 25, 2011. Such disconnecting all-wheel drive vehicles employ a
first disconnecting element in the front or primary driveline and a
second disconnecting element in the rear or secondary driveline. It
can be important in some instances that one or both of the first
and second disconnecting elements exhibit a relatively low drag
torque when not engaged (i.e., when not being used to actively
transmit rotary power). It can also be important in some instances
that one or both of the first and second disconnecting elements
allow for rotational synchronization of the drive axle and the
driveline before transmitting torque to the drive axles.
Multi-plate wet clutches can serve as both a synchronizer and a
torque transfer device. However, if one or both of the first and
second disconnecting elements includes a multi-plate clutch pack,
low drag is typically at least partially achieved by moving the
clutch plates a sufficiently far distance from one another. In this
regard, if the clutch plates are not separated by a sufficient
distance, the disconnecting element can have a drag torque that can
rival the drag torque of the (other) driveline components that are
to be "disconnected".
[0004] As the disconnecting drivelines must typically be capable of
transmitting relatively high torque, the clutch packs employed in
such devices generally include a relatively high number of clutch
plates. Due to the need for a relatively high normal force to
transmit high torque through such clutch packs, one common approach
is to employ a hydraulically-powered actuator, which is fed
hydraulic fluid via a high pressure pump, for applying the normal
force. In order to sufficiently space or separate a large quantity
of clutch plates, the actuator that applies the normal force to the
clutch pack must have a relatively long travel. Due to the
magnitude of the normal force and the relatively long length of
travel, such friction clutches have a relatively long engagement
time (i.e., a length of time between the point in time at which the
friction clutch begins to engage and the point in time at which the
friction clutch is fully engaged).
[0005] In view of the above remarks, an improved driveline
component that is capable of being disconnected is needed in the
art.
SUMMARY
[0006] This section provides a general summary of the disclosure,
and is not a comprehensive disclosure of its full scope or all of
its features.
[0007] The present teachings provide for a d disconnecting
driveline component including a housing, an input gear, a ring
gear, a differential assembly, a stub shaft, an axle shaft, a
clutch device, and a pilot clutch device. The input gear can be
received in the housing. The ring gear can be received in the
housing and can be meshingly engaged with the input gear to receive
power therefrom. The ring gear can be rotatable about an axis. The
differential assembly can be received in the housing and can
include a differential case and a differential gearset. The
differential case can be coupled to the ring gear for common
rotation about the axis. The differential gearset can be coupled to
the differential case to receive rotary power therefrom. The
differential gearset can have a pair of output members. The stub
shaft can be coupled to one of the pair of output members for
rotation therewith about the axis. The clutch device can include a
clutch input member, a clutch output member, a carrier, and a
collar. The clutch input member can be coupled to the stub shaft
for rotation therewith about the axis. The clutch output member can
be coupled to the axle shaft for rotation therewith about the axis.
The carrier can be axially movably but non-rotatably coupled to the
clutch input member. The collar can be axially-slidably but
non-rotatably coupled to one of the carrier and the clutch input
member for movement along the axis between a first position, in
which the collar can be coupled to the clutch output member to
transmit rotational power therebetween, and a second position in
which the collar can be rotatably decoupled from the clutch output
member. The pilot clutch device can include a pilot input member, a
pilot output member, and a pilot actuator. The pilot input member
can be axially-slidably but non-rotatably coupled to the carrier.
The pilot output member can being fixedly coupled to the clutch
output member. The pilot actuator can be selectively operable for
moving the pilot input member into frictional engagement with the
pilot output member.
[0008] The present teachings further provide for a disconnecting
driveline component including a housing, an input gear, a ring
gear, a differential assembly, a clutch device, and a pilot clutch
device. The input gear can be received in the housing. The ring
gear can be received in the housing and can be meshingly engaged
with the input gear to receive power therefrom. The ring gear can
be rotatable about an axis. The differential assembly can be
received in the housing and can include a differential case, and a
differential gearset. The differential case can include a first
case member, which can be coupled to the ring gear for common
rotation about the axis, and a second case member. The differential
gearset can be coupled to the second case member to receive rotary
power therefrom. The differential gearset can have a pair of output
members. The clutch device can include a clutch input member, a
clutch output member, a carrier, and a collar. The clutch input
member can be coupled to the first case member for rotation
therewith about the axis. The clutch output member can be coupled
to the second case member for rotation therewith about the axis.
The carrier can be axially movably but non-rotatably coupled to the
clutch input member. The collar can be axially-slidably but
non-rotatably coupled to one of the carrier and the clutch input
member for movement along the axis between a first position, in
which the collar can be coupled to the clutch output member to
transmit rotational power therebetween, and a second position in
which the collar can be rotatably decoupled from the clutch output
member. The pilot clutch device can include a pilot input member, a
pilot output member, and a pilot actuator. The pilot input member
can be axially-slidably but non-rotatably coupled to the carrier.
The pilot output member can be fixedly coupled to the clutch output
member. The pilot actuator can be selectively operable for moving
the pilot input member into frictional engagement with the pilot
output member.
[0009] The present teachings further provide a disconnecting
driveline component including a housing, an input gear, a ring
gear, a differential assembly, a shaft, a clutch device, and a
pilot clutch device. The input gear can be received in the housing.
The ring gear can be received in the housing and can be meshingly
engaged with the input gear to receive power therefrom. The ring
gear can be rotatable about an axis. The differential assembly can
be received in the housing and can include a differential case and
a differential gearset. The differential gearset can be coupled to
the differential case to receive rotary power therefrom. The
differential gearset can have a pair of output members. The shaft
can be coupled to one of the pair of output members. The clutch
device can be configured to selectively permit transmission of
rotary power between the ring gear and the shaft. The clutch device
can include a clutch input member, a clutch output member, and a
collar. The clutch input member can be coupled for common rotation
with one of the ring gear and the one of the pair of output
members. The clutch output member can be coupled for common
rotation with one of the differential case and the shaft. The
collar can be axially-slidable along the axis between a first
position, in which the collar couples the clutch input member to
the clutch output member to transmit rotational power therebetween,
and a second position in which the collar is rotatably decoupled
from one of the clutch input member and the clutch output member.
The pilot clutch device can include a pilot input member, a pilot
output member, and an electromagnet. The pilot input member can be
axially slidably but non-rotatably coupled to the carrier. The
pilot output member can be fixed to the clutch output member. The
electromagnet can be selectively operable for generating a magnetic
field that can draw the pilot input member into frictional
engagement with the pilot output member. The pilot clutch can
couple the clutch input member to the clutch output member when the
pilot input member frictionally engages the pilot output member and
the collar is in the second position.
[0010] Further areas of applicability will become apparent from the
description provided herein. The description and specific examples
in this summary are intended for purposes of illustration only and
are not intended to limit the scope of the present disclosure.
DRAWINGS
[0011] The drawings described herein are for illustrative purposes
only of selected embodiments and not all possible implementations,
and are not intended to limit the scope of the present
disclosure.
[0012] FIG. 1 is a schematic of a motor vehicle having an all-wheel
drive system with a disconnecting driveline component constructed
in accordance with the teachings of the present disclosure;
[0013] FIG. 2 is a sectional view of a portion of the disconnecting
driveline component of FIG. 1; and
[0014] FIG. 3 is a sectional view of a portion of a second
disconnecting driveline constructed in accordance with the
teachings of the present disclosure.
[0015] Corresponding reference numerals indicate corresponding
parts throughout the several views of the drawings.
DETAILED DESCRIPTION
[0016] Example embodiments will now be described more fully with
reference to the accompanying drawings.
[0017] With reference to FIG. 1 of the drawings, an exemplary
vehicle having a power transmitting component constructed in
accordance with the teachings of the present disclosure is
generally indicated by reference numeral 10. The vehicle 10 can
have a power train 12 and a drive line or drive train 14. The power
train 12 can be conventionally constructed and can include a power
source 16 and a transmission 18. The power source 16 can be
configured to provide propulsive power and can include an internal
combustion engine and/or an electric motor, for example. The
transmission 18 can receive propulsive power from the power source
16 and can output power to the drive train 14. The transmission 18
can have a plurality of automatically or manually-selected gear
ratios. The drive train 14 in the particular example provided is of
an all-wheel drive configuration, but those of skill in the art
will appreciate that the teachings of the present disclosure are
applicable to other drive train configurations, including
four-wheel drive configurations, rear-wheel drive configurations,
and front-wheel drive configurations.
[0018] The drive train 14 can include a front axle assembly 20, a
power take-off unit (PTU) 22, a prop shaft 24 and a disconnecting
driveline component 26. In the particular example provided, the
disconnecting driveline component is a rear axle assembly, but it
will be appreciated that the teachings of the present disclosure
have application to other driveline components. An output of the
transmission 18 can be coupled to an input of the front axle
assembly 20 to drive an input member 30 of the front axle assembly
20. The front axle assembly 20 and the PTU 22 are described in more
detail in commonly-assigned U.S. application Ser. No. 13/785,425,
the disclosure of which is incorporated by reference as if fully
set forth in detail herein. While described in U.S. application
Ser. No. 13/785,425 and herein as a two-speed PTU, the PTU 22 can
alternatively be configured in other ways, such as a single, or a
multi-speed PTU for example. Briefly, the PTU 22 can have a PTU
input member 32, which can receive rotary power from the input
member 30 of the front axle assembly 20, and a PTU output member 34
that can transmit rotary power to the prop shaft 24. The prop shaft
24 can couple the PTU output member 34 to the rear axle assembly 26
such that rotary power output by the PTU 22 is received by the rear
axle assembly 26. The front axle assembly 20 and the rear axle
assembly 26 could be driven on a full-time basis to drive front and
rear vehicle wheels 36 and 38, respectively. The drive train 14 can
include one or more clutches to interrupt the transmission of
rotary power through a part of the drive train 14 and/or modulate
torque transferred through the drive train 14. In the example
provided, the drive train 14 includes a PTU disconnect clutch 40, a
torque modulating clutch 44, and a plurality of clutches which are
incorporated into the rear axle assembly 26 as will be discussed in
more detail below. The PTU disconnect clutch 40 can be configured
to interrupt the transmission of rotary power into or through the
PTU 22, and can be any type of clutch disposed between the input
member 30 of the front axle assembly 20 and the PTU input member
32. The torque modulating clutch 44 can be configured to modulate
torque between the PTU 22 and the rear axle assembly 26.
[0019] With additional reference to FIG. 2, the rear axle assembly
26 can include a housing 50, an input pinion 52, a ring gear 54, a
differential assembly 56, a first clutch mechanism 58, a second
clutch mechanism 60, and a pair of axle shafts 62. The input pinion
52 can be conventionally housed in the housing 50 for rotation
about an input pinion axis 66. The input pinion 52 can be coupled
to the prop shaft 24 (FIG. 1) for rotation therewith. In the
example provided, the torque modulating clutch 44 (FIG. 1) is a
multi-plate, wet clutch disposed within the housing 50 between the
prop shaft 24 and the input pinion 52 and configured to modulate
torque transfer between the prop shaft 24 and the input pinion 52,
though other configurations can be used. The ring gear 54 can be
mounted in the housing 50 for rotation about a differential axis 68
that can be transverse, e.g., perpendicular, to the input pinion
axis 66. The ring gear 54 can be meshingly engaged with the input
pinion 52. The differential assembly 56 can be any means known in
the art for transmitting rotary power in a torque path between the
ring gear 54 and the axle shafts 62. In the particular example
provided, the differential assembly 56 includes a differential case
70, a differential gearset 72, and a first input member 74. The
differential case 70 can be supported within the housing 50 for
rotation relative to the housing 50 by bearings 94, 96. In the
example provided, bearings 94, 96 are disposed between the housing
50 and the differential case 70. The differential case 70 can
include a first case member 76, which can be fixedly coupled to the
ring gear 54, and a second case member 78. In the particular
example provided, the first case member 76 is fixedly coupled to or
unitarily formed with the second case member 78, and is
concentrically disposed about the second case member 78. The
differential gearset 72 can be mounted to the second case member 78
of the differential case 70 in a manner that permits rotary power
to be transmitted therebetween. For example, the differential
gearset 72 can include a pair of side gears 80, and first and
second differential pinions 82, 84, that are meshingly engaged with
the side gears 80. In the example provided, the side gears 80,
which are rotatably mounted on a cross-pin 86 that is fixedly
coupled to the second case member 78, and the differential pinions
82, 84 are bevel gears, with each of the differential pinions 82,
84 being meshingly engaged with both of the side gears 80. It will
be appreciated, however, that other types of differential gearsets
could be employed (e.g., helical gearsets in which pairs of the
differential pinions have helical teeth that are meshed together
and each one of the pair of differential pinions is meshed with the
helical teeth of a corresponding one of the side gears). One of the
axle shafts 62 can be coupled to the first differential pinion 82
for common rotation. The second differential pinion 84 can be
fixedly coupled to the first input member 74 for common rotation
therewith.
[0020] Each of the first and second clutch mechanisms 58 and 60 can
be employed to selectively couple the first input member 74 and the
other axle shaft 62 to one another for common rotation. The first
and second clutch mechanisms 58 and 60 can vary in their torque
capacity (i.e., the amount of torque that can be transmitted from
the input of the clutch to the output of the clutch in a
predetermined rotational direction and at a predetermined
rotational speed). For example, the first clutch mechanism 58 can
have a first torque capacity that can be greater than a second
torque capacity of the second clutch mechanism 60.
[0021] The first clutch mechanism 58 can include a first clutch 90
and a first clutch actuator 92. The first clutch 90 can include a
carrier 100, a collar 102, a first output member 104, and a first
clutch spring 106. The carrier 100 can have a base portion 108 and
an extending portion 110 fixedly coupled to the base portion 108.
The base portion 108 can have a generally plate or ring shape and
can be non-rotatably, but axially slidably coupled to the first
input member 74 for common rotation therewith. In the example
provided, the base portion 108 is co-axially disposed about the
first input member 74 and includes an interior spline or teeth 112
that is non-rotatably, but axially slidably engaged with an outer
mating spline or teeth 114 formed on the first input member 74. The
base portion 108 can extend radially outward from the first input
member 74. The extending portion 110 can be co-axially disposed
about the first input member 74 while being radially outward and
spaced apart from the first input member 74. The extending portion
110 can have a generally tubular shape. The extending portion 110
can include a return member 116 configured to axially translate the
collar 102 as will be discussed below. The return member 116 can
extend radially inward from an end of the extending portion 110
distal to the base portion 108.
[0022] The collar 102 can be non-rotatably, but axially slidably
coupled to the first input member 74 for common rotation therewith.
In the example provided, the collar 102 is co-axially disposed
about the first input member 74 and radially inward of the
extending portion 110 of the carrier 100. The collar 102 can be
slidably received within the tubular shape of the extending portion
110. In the example provided, the collar 102 includes an interior
spline or teeth 118 that is non-rotatably, but axially slidably
engaged with the outer mating spline 114 formed on the first input
member 74. The collar 102 can be axially translated between a first
position, in which the collar 102 is not engaged with the first
output member 104, and a second position, in which the collar 102
is engaged with the first output member 104.
[0023] The first output member 104 can be coupled for common
rotation with the other of the axle shafts 62 (i.e. the axle shaft
62 not coupled for common rotation with the first differential
pinion 82). In the example provided, the first output member 104 is
supported within a portion of the first input member 74 by bearing
98 and includes an inner spline or teeth 120 that is non-rotatably
engaged with an outer spline or teeth 122 formed on the other of
the axle shafts 62. The first output member 104 can include an
outer spline or teeth 124 axially in-line with the outer mating
spline 114 of the first input member 74 and configured to mate with
the interior spline 118 of the collar 102. When the collar 102 is
in the first position, the interior spline 118 can be engaged with
the outer mating spline 114 and dis-engaged from the outer spline
124. The collar 102 can be a length such that the interior spline
118 can be engaged with both the outer mating spline 114 and the
outer spline 124 when the collar 102 is in the second position, to
couple the first input member 74 to the first output member 104 for
common rotation.
[0024] The first clutch spring 106 can be disposed axially between
the base portion 108 and the collar 102 and be configured to
translate the collar 102 axially from the first position toward the
second position when the carrier 100 is translated in a first axial
direction 126. The first clutch spring 106 can allow for axial
compliance, such that the first clutch spring 106 can compress if
the interior spline 118 is not rotationally aligned with the outer
spline 124 when the carrier 100 translates in the first axial
direction 126. When the first clutch spring 106 compresses, the
first clutch spring 106 can bias the collar 102 in the first axial
direction 126 such that the first clutch spring 106 can move the
collar 102 toward the second position upon subsequent alignment of
the splines 118, 124. In the example provided, the first clutch
spring 106 is a coil spring disposed about the differential axis
68, radially inward of the extending portion 110 and radially
outward of the first input member 74, though other types of biasing
elements or configurations can be used.
[0025] The first clutch actuator 92 can be configured to axially
translate the carrier 100. The first clutch actuator 92 can include
a first actuator device 128 and a shift fork 130. The first
actuator device 128 can be any suitable device for translating the
shift fork 130 axially along the differential axis 68. For example,
the first actuator device 128 can be a hydraulically actuated ram,
a motor and lead screw, a ball-ramp actuator, or any other suitable
linear actuator. The shift fork 130 can be configured to be
linearly translated by the first actuator device 128 and can be
coupled to a portion of the carrier 100 to linearly translate the
carrier 100. In the example provided, the shift fork 130 is coupled
for axial translation with the base portion 108.
[0026] The second clutch mechanism 60 can include a second clutch
150 and a second clutch actuator 152. The second clutch 150 can
include a second input member 160, a second output member 162, and
a second clutch spring 164. The second input member 160 can be
non-rotatably, but axially slidably coupled to the first input
member 74 for common rotation therewith. In the example provided,
the second input member 160 is co-axially disposed about the first
input member 74, radially outward of the collar 102 and the
extending portion 110 of the carrier 100, and includes an interior
spline or teeth 166 that is non-rotatably, but axially slidably
engaged with an outer mating spline or teeth 168 formed on the
extending portion 110 of the carrier 100. The second input member
160 can also include a first friction surface 170. The second
output member 162 can include a second friction surface 172 facing
toward the first friction surface 170. The second output member 162
can be coupled to the first output member 104 for common rotation
therewith. The second clutch spring 164 can be configured to bias
the second input member 160 axially away from the second output
member 162. In the example provided, the second clutch spring 164
is a coil extension spring disposed radially about the extending
portion 110, axially between the base portion 108 and the second
input member 160, and coupled to the carrier 100 and the second
input member 160 to bias the second input member 160 in the
direction opposite the first axial direction 126, though other
types of biasing members and configurations can be used. The first
and second friction surfaces 170, 172 can be configured to transmit
rotary power when in contact with each other. The first and second
friction surfaces 170, 172 can be configured to transmit a
relatively low amount of torque, such that engagement between the
first and second friction surfaces 170, 172, can synchronize the
rotation of the second differential pinion 84 and the other of the
axle shafts 62 (i.e. the axle shaft 62 not coupled for common
rotation with the first differential pinion 82). The first and
second friction surfaces 170, 172 can be configured such that the
second input member 160 and second output member 162 do not
transmit the full drive torque provided by the first input member
74 when the ring gear 54 receives input torque from the input
pinion 52.
[0027] The second clutch actuator 152 can be configured to axially
translate the second input member 160 along the differential axis
68. In the example provided, the second clutch actuator 152
includes an electromagnet 180 disposed axially in-line with the
second input member 160 and second output member 162, though other
types of linear actuators and configurations can be used. The
electromagnet 180 can create a magnetic field configured to
overcome the second clutch spring 164 to attract the second input
member 160 axially toward the second output member 162 when an
electric current is provided to the electromagnet 180. In the
example provided, the second output member 162 is axially between
the second input member 160 and the electromagnet 180 and the
electromagnet 180 is radially outward of the extending portion 110
of the carrier 100.
[0028] In operation, when rotary power is to be transmitted from
the input pinion 52 to the rear wheels 38, the second clutch
actuator 152 can be activated to bring the second input member 160
and second output member 162 into engagement to synchronize the
rotation of the other of the axle shafts 62 (i.e. the axle shaft 62
not coupled for common rotation with the first differential pinion
82) with the second differential pinion 84. In the example
provided, the magnetic field provided by the electromagnet 180 can
be strong enough to induce synchronized rotation while being
insufficient to prevent slipping of the first and second friction
surfaces 170, 172, when under sufficient load. It is appreciated
that perfect synchronization is not necessary.
[0029] After the components of the rear axle assembly 26 are up to
speed, or synchronized, the first clutch actuator 92 can be
activated to translate the carrier 100 in the first axial direction
126. Axial translation of the carrier 100 in the first axial
direction 126 can cause the base portion 108 to axially translate
the first clutch spring 106 in the first axial direction 126. Axial
translation of the first clutch spring 106 in the first axial
direction 126 can cause the first clutch spring 106 to press
against the collar 102 to axially translate the collar 102 in the
first axial direction 126. Axial translation of the collar 102 can
bring the collar 102 into engagement with the first output member
104 and the first input member 74 to transfer rotary power
therebetween. When the rear axle assembly 26 is in a connected mode
(i.e. the collar 102 engages the first output member 104 and the
first input member 74 for common rotation), then the
synchronization function of the second clutch 60 is no longer
needed and the second clutch actuator 152 can be deactivated.
Deactivation of the electromagnet 180 can allow the second clutch
spring 164 to translate the second input member 160 in the
direction opposite the first axial direction 126, to disengage the
second input member 160 from the second output member 162.
[0030] To return the rear axle assembly 26 to a disconnected mode
(i.e. the collar 102 does not engage both of the first output
member 104 and the first input member 74 for common rotation), the
first clutch actuator 92 can be reversed to translate the carrier
100 in the direction opposite the first axial direction 126. The
return member 116 can engage the collar 102 to translate the collar
102 in the direction opposite the first axial direction 126, to
move the collar 102 out of engagement with the first output member
104. It is appreciated that when the rear axle assembly 26 is
disconnected, power does not need to be maintained to either the
first or second actuator 92, 152, to maintain the rear axle
assembly 26 in the disconnected mode. It is further appreciated
that once the first clutch mechanism 58 is engaged to transmit
rotary power from the second differential pinion 84 to the first
output member 104, power does not need to be maintained to either
the first or second actuator 92, 152, to maintain the rear axle
assembly 26 in the connected mode.
[0031] With reference to FIG. 3, a second construction of a rear
axle assembly is shown with reference numeral 26'. Rear axle
assembly 26' is similar to rear axle assembly 26 and similar
components are shown having similar primed reference numerals.
Accordingly, the descriptions of similarly numbered elements from
rear axle assembly 26 are incorporated herein by reference and only
differences will be discussed in detail. Specifically, the first
case member 76' of the differential case 70' can be separate from
and rotatable relative to the second case member 78'. In the
example provided, the first case member 76' is disposed
concentrically about the second case member 78' and is supported
within the housing 50' by bearing 302 and 304. Bearings 302, 304
can be disposed between the housing 50' and the first case member
76'. In the example provided the second case member 78' is
supported rotatably within the first case member 76' by bearing 306
and bearing 308. Bearing 306 can be disposed between the second
case member 78' and the housing 50'. Bearing 308 can be disposed
between the second case member 78' and the first case member 76'.
The first differential pinion 82' can be coupled to one of the axle
shafts 62' for common rotation therewith. The second differential
pinion 84' can be coupled to the other of the axle shafts 62' for
common rotation therewith, instead of being coupled for common
rotation with the first input member 74' as is the case with rear
axle assembly 26.
[0032] The first input member 74' can be disposed radially between
the first and second case members 76', 78' and can be supported
about the second case member 78' for rotation relative to the
second case member 78'. The first input member 74' can be coupled
to the first case member 76' for common rotation therewith. In the
example provided, the outer mating spline or teeth 114' can engage
an inner spline or teeth 310 formed on the first case member 76' to
couple the inner case member 76' and the first input member 74' for
common rotation.
[0033] The first and second clutch mechanisms 58' and 60' can be
configured similarly to the first and second clutch mechanisms 58
and 60 with regard to the first input member 74' and the first and
second output members 104', 162'. In contrast to the first clutch
mechanism 58, the first output member 104' can be coupled for
common rotation with the second case member 78', instead of the
other of the axle shafts 62'. In the example provided, the inner
spline or teeth 120' of the first output member 104' can be
non-rotatably coupled to an outer spline or teeth 312 formed on the
second case member 78' to couple the first output member 104' and
the second case member 78' for common rotation. In contrast to the
second clutch mechanism 60, the second clutch mechanism 60' can
synchronize the rotation of the first and second case members 76',
78' of the differential assembly 56', instead of the rotation of
the second differential pinion 84' and the other of the axle shafts
62'.
[0034] Operation of the rear axle assembly 26' is similar to
operation of the rear axle assembly 26. When rotary power is to be
transmitted from the input pinion 52' to the rear wheels 38 (FIG.
1), the second clutch actuator 152' can be activated to bring the
second input member 160' and second output member 162' into
engagement to synchronize the rotation of the first and second case
members 76', 78'. In the example provided, the magnetic field
provided by the electromagnet 180' can be strong enough to induce
synchronized rotation while being insufficient to prevent slipping
of the first and second friction surfaces 170', 172', when under
sufficient load. It is appreciated that perfect synchronization is
not necessary.
[0035] After the components of the rear axle assembly 26' are up to
speed, or synchronized, the first clutch actuator 92' can be
activated to translate the carrier 100' in the first axial
direction 126'. Axial translation of the carrier 100' can cause the
base portion 108' to axially translate the first clutch spring 106'
in the first axial direction 126'. Axial translation of the first
clutch spring 106' in the first axial direction 126' can cause the
first clutch spring 106' to press against the collar 102' to
axially translate the collar 102' in the first axial direction
126'. Axial translation of the collar 102' can bring the collar
102' into engagement with the first output member 104' and the
first input member 74' to transfer rotary power therebetween and
thus transfer rotary power between the first and second case
members 76', 78'. When the rear axle assembly 26' is in a connected
mode (i.e. the collar 102' engages the first output member 104' and
the first input member 74' for common rotation), then the
synchronization function of the second clutch 60' is no longer
needed and the second clutch actuator 152' can be deactivated.
Deactivation of the electromagnet 180' can allow the second clutch
spring 164' to translate the second input member 160' in the
direction opposite the first axial direction 126', to disengage the
second input member 160' from the second output member 162'.
[0036] To return the rear axle assembly 26' to a disconnected mode
(i.e. the collar 102' does not engage both of the first output
member 104' and the first input member 74' for common rotation),
the first clutch actuator 92' can be reversed to translate the
carrier 100' in the direction opposite the first axial direction
126'. The return member 116' can engage the collar 102' to
translate the collar 102' in the direction opposite the first axial
direction 126', to move the collar 102' out of engagement with the
first output member 104'. It is appreciated that when the rear axle
assembly 26' is disconnected, power does not need to be maintained
to either the first or second actuator 92', 152', to maintain the
rear axle assembly 26' in the disconnected mode. It is further
appreciated that once the first clutch mechanism 58' is engaged to
transmit rotary power from the first case member 76' to the second
case member 78', power does not need to be maintained to either the
first or second actuator 92', 152', to maintain the rear axle
assembly 26' in the connected mode.
[0037] Thus, the rear axle assemblies 26 and 26' allow for
synchronization and torque transfer in a disconnecting all-wheel
drive driveline component without the drag and other parasitic
losses associated with typical wet clutches.
[0038] The foregoing description of the embodiments has been
provided for purposes of illustration and description. It is not
intended to be exhaustive or to limit the disclosure. Individual
elements or features of a particular embodiment are generally not
limited to that particular embodiment, but, where applicable, are
interchangeable and can be used in a selected embodiment, even if
not specifically shown or described. The same may also be varied in
many ways. Such variations are not to be regarded as a departure
from the disclosure, and all such modifications are intended to be
included within the scope of the disclosure.
[0039] Example embodiments are provided so that this disclosure
will be thorough, and will fully convey the scope to those who are
skilled in the art. Numerous specific details are set forth such as
examples of specific components, devices, and methods, to provide a
thorough understanding of embodiments of the present disclosure. It
will be apparent to those skilled in the art that specific details
need not be employed, that example embodiments may be embodied in
many different forms and that neither should be construed to limit
the scope of the disclosure. In some example embodiments,
well-known processes, well-known device structures, and well-known
technologies are not described in detail.
[0040] The terminology used herein is for the purpose of describing
particular example embodiments only and is not intended to be
limiting. As used herein, the singular forms "a," "an," and "the"
may be intended to include the plural forms as well, unless the
context clearly indicates otherwise. The terms "comprises,"
"comprising," "including," and "having," are inclusive and
therefore specify the presence of stated features, integers, steps,
operations, elements, and/or components, but do not preclude the
presence or addition of one or more other features, integers,
steps, operations, elements, components, and/or groups thereof. The
method steps, processes, and operations described herein are not to
be construed as necessarily requiring their performance in the
particular order discussed or illustrated, unless specifically
identified as an order of performance. It is also to be understood
that additional or alternative steps may be employed.
[0041] When an element or layer is referred to as being "on,"
"engaged to," "connected to," or "coupled to" another element or
layer, it may be directly on, engaged, connected or coupled to the
other element or layer, or intervening elements or layers may be
present. In contrast, when an element is referred to as being
"directly on," "directly engaged to," "directly connected to," or
"directly coupled to" another element or layer, there may be no
intervening elements or layers present. Other words used to
describe the relationship between elements should be interpreted in
a like fashion (e.g., "between" versus "directly between,"
"adjacent" versus "directly adjacent," etc.). As used herein, the
term "and/or" includes any and all combinations of one or more of
the associated listed items.
[0042] Although the terms first, second, third, etc. may be used
herein to describe various elements, components, regions, layers
and/or sections, these elements, components, regions, layers and/or
sections should not be limited by these terms. These terms may be
only used to distinguish one element, component, region, layer or
section from another region, layer or section. Terms such as
"first," "second," and other numerical terms when used herein do
not imply a sequence or order unless clearly indicated by the
context. Thus, a first element, component, region, layer or section
discussed below could be termed a second element, component,
region, layer or section without departing from the teachings of
the example embodiments.
[0043] Spatially relative terms, such as "inner," "outer,"
"beneath," "below," "lower," "above," "upper," and the like, may be
used herein for ease of description to describe one element or
feature's relationship to another element(s) or feature(s) as
illustrated in the figures. Spatially relative terms may be
intended to encompass different orientations of the device in use
or operation in addition to the orientation depicted in the
figures. For example, if the device in the figures is turned over,
elements described as "below" or "beneath" other elements or
features would then be oriented "above" the other elements or
features. Thus, the example term "below" can encompass both an
orientation of above and below. The device may be otherwise
oriented (rotated 90 degrees or at other orientations) and the
spatially relative descriptors used herein interpreted
accordingly.
* * * * *