U.S. patent application number 16/408698 was filed with the patent office on 2020-11-12 for hydrokinetic torque-coupling device having lock-up clutch with dual piston assembly and selectable one-way clutch.
The applicant listed for this patent is Valeo Kapec Co., Ltd.. Invention is credited to Xuexian YIN.
Application Number | 20200355251 16/408698 |
Document ID | / |
Family ID | 1000005178508 |
Filed Date | 2020-11-12 |
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United States Patent
Application |
20200355251 |
Kind Code |
A1 |
YIN; Xuexian |
November 12, 2020 |
HYDROKINETIC TORQUE-COUPLING DEVICE HAVING LOCK-UP CLUTCH WITH DUAL
PISTON ASSEMBLY AND SELECTABLE ONE-WAY CLUTCH
Abstract
A hydrokinetic torque-coupling device for a hybrid electric
vehicle, comprising a casing rotatable about a rotational axis, a
torque converter including an impeller wheel and a turbine wheel, a
lockup clutch including a dual piston assembly, and a selectable
one-way clutch disposed outside of the casing. The selectable
one-way clutch includes an outer race, torque transmitting
elements, an inner race drivingly and non-rotatably connectable to
the outer race through the torque transmitting elements, and a
plurality of actuator members configured to circumferentially
displace one of the torque transmitting elements in each pair of
the torque transmitting elements. The dual piston assembly includes
a main piston and at least one secondary piston having actuator
rods. One torque transmitting element of each pair of the torque
transmitting elements is moveable by axial movement of the actuator
rods of the at least one second lockup piston acting to the
actuator members.
Inventors: |
YIN; Xuexian; (Auburn Hills,
MI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Valeo Kapec Co., Ltd. |
Daegu |
|
KR |
|
|
Family ID: |
1000005178508 |
Appl. No.: |
16/408698 |
Filed: |
May 10, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F16H 2045/002 20130101;
F16H 45/02 20130101; F16D 41/064 20130101 |
International
Class: |
F16H 45/02 20060101
F16H045/02; F16D 41/064 20060101 F16D041/064 |
Claims
1. A hydrokinetic torque-coupling device for a hybrid electric
vehicle, comprising: a casing rotatable about a rotational axis; a
torque converter including an impeller wheel and a turbine wheel
disposed in the casing coaxially with the impeller wheel; a lockup
clutch including a dual piston assembly and being switchable
between a hydrodynamic transmission mode, in which the turbine
wheel is rotatable relative to the casing, and a lockup mode, in
which the turbine wheel is non-rotatably coupled to the casing; and
a selectable one-way clutch disposed outside of the casing, the
selectable one-way clutch including an outer race, a plurality of
pairs of torque transmitting elements each including first and
second torque transmitting elements, an inner race drivingly and
non-rotatably connectable to the outer race through the first and
second torque transmitting elements, and a plurality of actuator
members configured to circumferentially displace the first torque
transmitting elements in each of the pairs of the torque
transmitting elements; each of the first and second torque
transmitting elements of each of the pairs of the torque
transmitting elements selectively circumferentially moveable
relative to at least one of the outer race and the inner race
between an engaged position, in which the outer race is
non-rotatably coupled to the inner race of the selectable one-way
clutch, and a disengaged position, in which the outer race is
rotatable relative to the inner race of the selectable one-way
clutch; the dual piston assembly including a main piston and at
least one secondary piston mounted to the main piston and axially
moveable relative to the main piston and the casing; the main
piston of the dual piston assembly selectively axially moveable
relative to the casing and the at least one secondary piston
between a lockup position, in which the main piston is
non-rotatably coupled to the casing, and a non-lockup position, in
which the main piston is rotatable relative to the casing; the at
least one secondary piston having a plurality of actuator rods
unitary with the at least one secondary piston; the first torque
transmitting elements of each of the pairs of the torque
transmitting elements selectively circumferentially moveable from
the engaged position to the disengaged position by axial movement
of the actuator rods of the at least one second lockup piston
acting to the actuator members.
2. The hydrokinetic torque-coupling device as defined in claim 1,
wherein the outer race is non-moveably secured to the casing, and
wherein the inner race is rotatable relative to the casing.
3. The hydrokinetic torque-coupling device as defined in claim 1,
wherein each of the actuator members is configured to cooperate
with one of the actuator rods of the at least one secondary
piston.
4. The hydrokinetic torque-coupling device as defined in claim 1,
wherein the dual piston assembly includes a plurality of secondary
pistons mounted to the main piston and axially moveable relative to
the main piston and the casing, and wherein each of the secondary
pistons has one of the actuator rods unitary with one of the
secondary pistons.
5. The hydrokinetic torque-coupling device as defined in claim 1,
wherein each of the actuator members is circumferentially
displaceable along an inner raceway of the inner race.
6. The hydrokinetic torque-coupling device as defined in claim 1,
wherein the first and second torque transmitting elements are first
and second rollers, respectively.
7. The hydrokinetic torque-coupling device as defined in claim 6,
wherein each of the actuator members includes a support portion
adjacent to and configured to engage one of the first rollers of
each of the pairs of the torque transmitting elements, and an
actuator portion outwardly extending from the support portion away
from the first roller.
8. The hydrokinetic torque-coupling device as defined in claim 1,
wherein a free distal end of each of the actuator rods of the at
least one secondary piston has a conical part adjacent to a tip of
each of the piston rods.
9. The hydrokinetic torque-coupling device as defined in claim 8,
wherein the conical part of the free distal end of each of the
actuator rods of the at least one secondary piston is configured to
cooperate with an actuator edge of the actuator portion of one of
the actuator members.
10. The hydrokinetic torque-coupling device as defined in claim 1,
wherein the at least one secondary piston is axially moveable
relative to the main piston and the casing between an extended
position and a retracted position with respect to the main piston,
wherein the first torque transmitting element of each of the pairs
of the torque transmitting elements is in the engaged position when
the at least one secondary piston is in the extended position, and
wherein the first torque transmitting element of each of the pairs
of the torque transmitting elements is in the disengaged position
when the at least one secondary piston is in the retracted
position.
11. The hydrokinetic torque-coupling device as defined in claim 1,
wherein the at least one secondary piston is axially biased toward
the extended position by at least one compression spring.
12. The hydrokinetic torque-coupling device as defined in claim 1,
wherein the first and second torque transmitting elements of each
of the pairs of the torque transmitting elements is biased by
corresponding first and second springs, respectively, toward the
engaged positions thereof.
13. The hydrokinetic torque-coupling device as defined in claim 1,
wherein a radially inner surface of the outer race includes a
plurality of evenly circumferentially spaced first and second cam
ramps arranged in pairs, and wherein a number of pairs of the first
and second cam ramps corresponds to a number of pairs of the torque
transmitting elements.
14. The hydrokinetic torque-coupling device as defined in claim 1,
further comprising a torsional vibration damper disposed outside of
the casing so that the selectable one-way clutch is disposed
between the casing and the torsional vibration damper.
15. The hydrokinetic torque-coupling device as defined in claim 14,
wherein the torsional vibration damper includes a drive member, a
driven member and a plurality of circumferentially acting elastic
members disposed in series relative to each other between the drive
member and the driven member.
16. The hydrokinetic torque-coupling device as defined in claim 15,
wherein the outer race is non-moveably secured to the casing, and
wherein the inner race is non-moveably secured to the driven member
of the torsional vibration damper and is rotatable relative to the
casing.
17. The hydrokinetic torque-coupling device as defined in claim 1,
wherein the casing includes a cover shell and an impeller shell
disposed coaxially with and axially opposite to the cover shell,
and wherein the cover shell and the impeller shell are non-movably
connected to one another.
18. The hydrokinetic torque-coupling device as defined in claim 17,
wherein the outer race of the selectable one-way clutch is
non-rotatably connected to the cover shell of the casing, and
wherein the inner race is rotatable relative to the casing.
19. The hydrokinetic torque-coupling device as defined in claim 17,
wherein the main piston includes a radially oriented annular piston
body and an annular hub portion having a cylindrical flange, and
wherein the at least one secondary piston includes a head member, a
cylindrical skirt defining a hollow chamber within the at least one
secondary piston, and a piston rod axially extending from the head
member through the main piston and through the cover shell of the
casing.
20. The hydrokinetic torque-coupling device as defined in claim 17,
wherein the main piston includes a radially oriented annular piston
body and at least one axially protruding boss receiving the at
least one secondary piston therein so that the at least one
secondary piston is axially moveable relative the at least one boss
of the main piston and the cover shell.
21. The hydrokinetic torque-coupling device as defined in claim 20,
wherein the cover shell of the casing includes at least one axially
protruding piston cup formed integrally with the cover shell of the
casing and receiving the at least one boss of the main piston
therein so that the at least one boss of the main piston is axially
moveable relative the at least one piston cup of the cover shell of
the casing.
22. A method of operation of a hydrokinetic torque-coupling device
for a hybrid electric vehicle comprising an internal combustion
engine and an electrical machine, the hydrokinetic torque-coupling
device comprising: a casing rotatable about a rotational axis and
drivingly coupled to the electrical machine; a torque converter
including an impeller wheel and a turbine wheel disposed in the
casing coaxially with the impeller wheel; a lockup clutch including
a dual piston assembly and being switchable between a hydrodynamic
transmission mode, in which the turbine wheel is rotatable relative
to the casing, and a lockup mode, in which the turbine wheel is
non-rotatably coupled to the casing; and a selectable one-way
clutch disposed outside of the casing, the selectable one-way
clutch including an outer race, a plurality of pairs of torque
transmitting elements each including first and second torque
transmitting elements, an inner race drivingly and non-rotatably
connectable to the outer race through the first and second torque
transmitting elements, and a plurality of actuator members
configured to circumferentially displace the first torque
transmitting elements in each of the pairs of the torque
transmitting elements; each of the first and second torque
transmitting elements of each of the pairs of the torque
transmitting elements selectively circumferentially moveable
relative to at least one of the outer race and the inner race
between an engaged position, in which the outer race is
non-rotatably coupled to the inner race of the selectable one-way
clutch, and a disengaged position, in which the outer race is
rotatable relative to the inner race of the selectable one-way
clutch; the dual piston assembly including a main piston and at
least one secondary piston mounted to the main piston and axially
moveable relative to the main piston and the casing; the main
piston of the dual piston assembly selectively axially moveable
relative to the casing and the at least one secondary piston
between a lockup position, in which the main piston is
non-rotatably coupled to the casing, and a non-lockup position, in
which the main piston is rotatable relative to the casing; the at
least one secondary piston having a plurality of actuator rods
unitary with the at least one secondary piston; the first torque
transmitting elements of each of the pairs of the torque
transmitting elements selectively circumferentially moveable from
the engaged position to the disengaged position by axial movement
of the actuator rods of the at least one second lockup piston
acting to the actuator members; the method comprising the step of
selectively controlling axial displacement of the dual lockup
piston assembly by regulating hydraulic pressure to the main piston
and the at least one secondary piston in order to configure the
first torque transmitting elements of the selectable one-way clutch
in a desired one of the engaged position and the disengaged
position.
23. A hybrid electric vehicle including an internal combustion
engine, at least one rotary electric machine and a hydrokinetic
torque-coupling device mechanically coupling the internal
combustion engine and the at least one rotary electric machine, the
hydrokinetic torque-coupling device comprising: a casing rotatable
about a rotational axis; a torque converter including an impeller
wheel and a turbine wheel disposed in the casing coaxially with the
impeller wheel; a lockup clutch including a dual piston assembly
and being switchable between a hydrodynamic transmission mode, in
which the turbine wheel is rotatable relative to the casing, and a
lockup mode, in which the turbine wheel is non-rotatably coupled to
the casing; and a selectable one-way clutch disposed outside of the
casing, the selectable one-way clutch including an outer race, a
plurality of pairs of torque transmitting elements each including
first and second torque transmitting elements, an inner race
drivingly and non-rotatably connectable to the outer race through
the first and second torque transmitting elements, and a plurality
of actuator members configured to circumferentially displace the
first torque transmitting elements in each of the pairs of the
torque transmitting elements; each of the first and second torque
transmitting elements of each of the pairs of the torque
transmitting elements selectively circumferentially moveable
relative to at least one of the outer race and the inner race
between an engaged position, in which the outer race is
non-rotatably coupled to the inner race of the selectable one-way
clutch, and a disengaged position, in which the outer race is
rotatable relative to the inner race of the selectable one-way
clutch; the dual piston assembly including a main piston and at
least one secondary piston mounted to the main piston and axially
moveable relative to the main piston and the casing; the main
piston of the dual piston assembly selectively axially moveable
relative to the casing and the at least one secondary piston
between a lockup position, in which the main piston is
non-rotatably coupled to the casing, and a non-lockup position, in
which the main piston is rotatable relative to the casing; the at
least one secondary piston having a plurality of actuator rods
unitary with the at least one secondary piston; the first torque
transmitting elements of each of the pairs of the torque
transmitting elements selectively circumferentially moveable from
the engaged position to the disengaged position by axial movement
of the actuator rods of the at least one second lockup piston
acting to the actuator members.
24. A hybrid electric vehicle, comprising: an internal combustion
engine; an electric machine; ground engaging wheels; a torque
transmitting system operably associate with the internal combustion
engine, the electric machine and the ground engaging wheels; and a
hydrokinetic torque-coupling device of claim 1 operably associated
with the torque transmitting system.
Description
FIELD OF THE INVENTION
[0001] This invention generally relates to fluid coupling devices,
and more particularly to a hydrokinetic torque-coupling device for
a vehicle hybrid powertrain system having a lock-up clutch with a
dual piston structure and selectable one-way clutch, and a method
of making the same.
BACKGROUND OF THE INVENTION
[0002] Known hybrid powertrain systems include an internal
combustion engine and an electric motor/generator that are coupled
to a vehicle transmission to transfer torque to a driveline for
tractive effort. Known electric motor/generators are supplied
electric power from energy storage systems, such as electric
batteries. Hybrid powertrain systems may operate in various modes
to generate and transfer propulsion power to vehicle wheels.
[0003] While hybrid powertrain systems, including but not limited
to those discussed above, have proven to be acceptable for
vehicular driveline applications and conditions, improvements that
may enhance their performance and cost are possible.
BRIEF SUMMARY OF THE INVENTION
[0004] According to a first aspect of the invention, a hydrokinetic
torque-coupling device for a hybrid electric vehicle comprises a
casing rotatable about a rotational axis, a torque converter
including an impeller wheel and a turbine wheel disposed in the
casing coaxially with the impeller wheel, a lockup clutch including
a dual piston assembly and being switchable between a hydrodynamic
transmission mode, in which the turbine wheel is rotatable relative
to the casing, and a lockup mode, in which the turbine wheel is
non-rotatably coupled to the casing, and a selectable one-way
clutch disposed outside of the casing. The selectable one-way
clutch includes an outer race, a plurality of pairs of torque
transmitting elements each including first and second torque
transmitting elements, an inner race drivingly and non-rotatably
connectable to the outer race through the first and second torque
transmitting elements, and a plurality of actuator members
configured to circumferentially displace the first torque
transmitting elements in each of the pairs of the torque
transmitting elements. Each of the first and second torque
transmitting elements of each of the pairs of the torque
transmitting elements is selectively circumferentially moveable
relative to at least one of the outer race and the inner race
between an engaged position, in which the outer race is
non-rotatably coupled to the inner race of the selectable one-way
clutch, and a disengaged position, in which the outer race is
rotatable relative to the inner race of the selectable one-way
clutch. The dual piston assembly includes a main piston and at
least one secondary piston mounted to the main piston and axially
moveable relative to the main piston and the casing. The main
piston of the dual piston assembly is selectively axially moveable
relative to the casing and the at least one secondary piston
between a lockup position, in which the main piston is
non-rotatably coupled to the casing, and a non-lockup position, in
which the main piston is rotatable relative to the casing. The at
least one secondary piston has a plurality of actuator rods unitary
with the at least one secondary piston. The first torque
transmitting elements of each of the pairs of torque transmitting
elements are selectively circumferentially moveable from the
engaged position to the disengaged position by axial movement of
the actuator rods of the at least one second lockup piston acting
to the actuator members.
[0005] According to a second aspect of the invention, a method of
operation a hydrokinetic torque-coupling device for a hybrid
electric vehicle comprising an internal combustion engine and an
electrical machine is disclosed. The hydrokinetic torque-coupling
device comprises a casing rotatable about a rotational axis and
drivingly coupled to the electrical machine, a torque converter
including an impeller wheel and a turbine wheel disposed in the
casing coaxially with the impeller wheel, a lockup clutch including
a dual piston assembly and being switchable between a hydrodynamic
transmission mode, in which the turbine wheel is rotatable relative
to the casing, and a lockup mode, in which the turbine wheel is
non-rotatably coupled to the casing, and a selectable one-way
clutch disposed outside of the casing. The selectable one-way
clutch includes an outer race, a plurality of pairs of torque
transmitting elements each including first and second torque
transmitting elements, an inner race drivingly and non-rotatably
connectable to the outer race through the first and second torque
transmitting elements, and a plurality of actuator members
configured to circumferentially displace the first torque
transmitting elements in each of the pairs of the torque
transmitting elements. Each of the first and second torque
transmitting elements of each of the pairs of the torque
transmitting elements is selectively circumferentially moveable
relative to at least one of the outer race and the inner race
between an engaged position, in which the outer race is
non-rotatably coupled to the inner race of the selectable one-way
clutch, and a disengaged position, in which the outer race is
rotatable relative to the inner race of the selectable one-way
clutch. The dual piston assembly includes a main piston and at
least one secondary piston mounted to the main piston and axially
moveable relative to the main piston and the casing. The main
piston of the dual piston assembly is selectively axially moveable
relative to the casing and the at least one secondary piston
between a lockup position, in which the main piston is
non-rotatably coupled to the casing, and a non-lockup position, in
which the main piston is rotatable relative to the casing. The at
least one secondary piston has a plurality of actuator rods unitary
with the at least one secondary piston. The first torque
transmitting elements of each of the pairs of the torque
transmitting elements is selectively circumferentially moveable
from the engaged position to the disengaged position by axial
movement of the actuator rods of the at least one second lockup
piston acting to the actuator members. The method of operation of
the hydrokinetic torque-coupling device the step of selectively
controlling axial displacement of the dual lockup piston assembly
by regulating hydraulic pressure to the main piston and the at
least one secondary piston in order to configure the first torque
transmitting elements of the selectable one-way clutch in a desired
one of the engaged position and the disengaged position.
[0006] Other aspects of the invention, including apparatus,
devices, systems, converters, processes, and the like which
constitute part of the invention, will become more apparent upon
reading the following detailed description of the exemplary
embodiments.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)
[0007] FIG. 1 is a schematic view of a hybrid powertrain system in
accordance with the present invention;
[0008] FIG. 2 is a sectional half-view of a hydrokinetic
torque-coupling device in accordance with an exemplary embodiment
of the present invention in a first mode of operation;
[0009] FIG. 3 is an enlarged view of a fragment of the hydrokinetic
torque-coupling device of FIG. 2 showing a turbine wheel, a lock-up
clutch and a selectable one-way clutch (SOWC);
[0010] FIG. 4 is an enlarged view of a fragment of the hydrokinetic
torque-coupling device of FIG. 2 showing the lock-up clutch, the
selectable one-way clutch (SOWC) and a torsional vibration
damper;
[0011] FIG. 5 is an enlarged view of a fragment of the hydrokinetic
torque-coupling device shown in the rectangle "5" of FIG. 2;
[0012] FIG. 6 is an exploded assembly view of the lock-up clutch
with a dual piston assembly and a cover shell in accordance with
the exemplary embodiment of the present invention;
[0013] FIG. 7 is a perspective view of the dual piston assembly
mounted to the cover shell in accordance with the exemplary
embodiment of the present invention;
[0014] FIG. 8 is a perspective view of a main piston of the dual
piston assembly in accordance with the exemplary embodiment of the
present invention;
[0015] FIG. 9 is a perspective view of a secondary pistons of the
dual piston assembly in accordance with the exemplary embodiment of
the present invention;
[0016] FIG. 10 is an exploded assembly view of the selectable
one-way clutch (SOWC) in accordance with the first exemplary
embodiment of the present invention;
[0017] FIG. 11 is a perspective view of an outer race of the SOWC
in accordance with the exemplary embodiment of the present
invention;
[0018] FIG. 12 is a perspective view of actuator members of the
SOWC in accordance with the exemplary embodiment of the present
invention;
[0019] FIG. 13 is a front view of the SOWC in accordance with the
exemplary embodiment of the present invention in a deactivated
state also showing free distal ends of piston rods of the secondary
pistons acting on the actuator members of the SOWC;
[0020] FIG. 14 is a cross-sectional view of the SOWC according to
the exemplary embodiment of the present invention taken along the
lines 14-14 in FIG. 13;
[0021] FIG. 15 is an enlarged perspective front view of the SOWC in
accordance with the exemplary embodiment of the present invention
in the deactivated state showing a pair of first and second rollers
and the free distal end of the piston rod of the secondary
piston;
[0022] FIG. 16 is a front view of the SOWC in accordance with the
exemplary embodiment of the present invention in the deactivated
state without showing the free distal ends of the piston rods of
the secondary pistons acting on the actuator members of the
SOWC;
[0023] FIG. 17 is a rear view of the SOWC in the deactivated state
in accordance with the exemplary embodiment of the present
invention;
[0024] FIG. 18A is an enlarged rear sectional view of the SOWC in
accordance with the exemplary embodiment of the present invention
in the deactivated state showing a pair of first and second
rollers;
[0025] FIG. 18B is an enlarged rear sectional view of the SOWC in
accordance with the exemplary embodiment of the present invention
in the deactivated state showing a first roller and a corresponding
actuator member;
[0026] FIG. 19 is a sectional view of the hydrokinetic
torque-coupling device in accordance with the exemplary embodiment
of the present invention in a second mode of operation;
[0027] FIG. 20 is an enlarged view of a fragment of the
hydrokinetic torque-coupling device shown in the rectangle "20" of
FIG. 19;
[0028] FIG. 21 is a sectional view of the hydrokinetic
torque-coupling device in accordance with the exemplary embodiment
of the present invention in a third mode of operation;
[0029] FIG. 22 is an enlarged view of a fragment of the
hydrokinetic torque-coupling device shown in the rectangle "22" of
FIG. 21;
[0030] FIG. 23 is a front sectional view of the SOWC in accordance
with the exemplary embodiment of the present invention in an
activated state also showing the free distal ends of the piston
rods of the secondary pistons acting on the actuator members of the
SOWC;
[0031] FIG. 24 is a cross-sectional view of the SOWC according to
the exemplary embodiment of the present invention taken along the
lines 24-24 in FIG. 23;
[0032] FIG. 25 is a sectional view of the hydrokinetic
torque-coupling device in accordance with the exemplary embodiment
of the present invention in a fourth mode of operation; and
[0033] FIG. 26 is an enlarged view of a fragment of the
hydrokinetic torque-coupling device shown in the rectangle "26" of
FIG. 25.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENT(S) AND EMBODIED
METHOD(S) OF THE INVENTION
[0034] Reference will now be made in detail to exemplary
embodiments and methods of the invention as illustrated in the
accompanying drawings, in which like reference characters designate
like or corresponding parts throughout the drawings. It should be
noted, however, that the invention in its broader aspects is not
limited to the specific details, representative devices and
methods, and illustrative examples shown and described in
connection with the exemplary embodiments and methods.
[0035] This description of exemplary embodiments is intended to be
read in connection with the accompanying drawings, which are to be
considered part of the entire written description. In the
description, relative terms such as "horizontal," "vertical," "up,"
"down," "upper", "lower", "right", "left", "top" and "bottom" as
well as derivatives thereof (e.g., "horizontally," "downwardly,"
"upwardly," etc.) should be construed to refer to the orientation
as then described or as shown in the drawing figure under
discussion. These relative terms are for convenience of description
and normally are not intended to require a particular orientation.
Terms concerning attachments, coupling and the like, such as
"connected" and "interconnected," refer to a relationship wherein
structures are secured or attached to one another either directly
or indirectly through intervening structures, as well as both
movable or rigid attachments or relationships, unless expressly
described otherwise. The term "operatively connected" is such an
attachment, coupling or connection that allows the pertinent
structures to operate as intended by virtue of that relationship.
The term "integral" (or "unitary") relates to a part made as a
single part, or a part made of separate components fixedly (i.e.,
non-moveably) connected together. Additionally, the words "a" and
"an" as used in the claims means "at least one" and the word "two"
as used in the claims means "at least two". For the purpose of
clarity, some technical material that is known in the related art
has not been described in detail in order to avoid unnecessarily
obscuring the disclosure.
[0036] FIG. 1 shows a schematic view of a hybrid powertrain system
2 of a hybrid motor vehicle in accordance with the present
invention. The hybrid powertrain system 2 comprises multiple
torque-generating devices, including an internal combustion engine
(ICE) 4 and at least one rotary electric machine (such as a motor,
generator or motor/generator) 6. The ICE 4 and the electric machine
6 are mechanically coupled via a hydrokinetic torque-coupling
device 10 and a transmission 3 to transfer propulsion power to
vehicle wheels 1. The hydrokinetic torque-coupling device 10 of the
present invention may be employed in any suitable powertrain
configuration that includes the internal combustion engine 4 and
the electric machine 6 coupled via the hydrokinetic torque-coupling
device 10 and the transmission 3. The hybrid powertrain system 2
may be employed in vehicles including, but not limited to,
passenger vehicles, light-duty or heavy-duty trucks, utility
vehicles, agricultural vehicles, industrial/warehouse vehicles,
recreational off-road vehicles, etc.
[0037] The hybrid powertrain system 2 is configured so that the ICE
4 and the electric machine 6 are mechanically coupled to the
transmission 3 employing the hydrokinetic torque-coupling device
10.
[0038] The hydrokinetic torque-coupling device in accordance with
an exemplary embodiment of the present invention is generally
represented in the accompanying drawings by reference numeral 10,
as best shown in FIG. 2. The hydrokinetic torque-coupling device 10
is intended to couple first and/or second driving shafts to a
driven shaft 8, for example in the hybrid powertrain system 2 of
the hybrid motor vehicle. In this case, the first driving shaft is
an output shaft (such as a crankshaft) 5 of the ICE 4 of the hybrid
motor vehicle, and the second driving shaft is an output shaft 7 of
the rotary electric machine 6, as best shown in FIG. 1. The driven
shaft 8 is an input shaft of a transmission (or gearbox) 3 of the
hybrid motor vehicle, as shown in FIG. 1. Thus, the hydrokinetic
torque-coupling device 10 is intended to couple the ICE 4 of the
hybrid motor vehicle and/or the rotary electric machine 6 to the
driven shaft 8.
[0039] The hydrokinetic torque-coupling device 10 includes a sealed
casing 12 filled with a fluid, such as oil or transmission fluid,
and rotatable about a rotational axis X, a hydrokinetic torque
converter 14, a lock-up clutch 16, an elastic damping device (or
torsional vibration damper) 18 and a selectable one-way clutch
(SOWC) 90. As best shown in FIG. 2, the lock-up clutch 16 is
disposed in the casing 12, while the torsional vibration damper 18
and the SOWC 90 are disposed outside of the casing 12.
[0040] The sealed casing 12, the torque converter 14, the lock-up
clutch 16, the torsional vibration damper 18 and the SOWC 90 are
all rotatable about the rotational axis X. As is known in the art,
the torque-coupling device 10 is generally symmetrical about the
rotational axis X. Hereinafter the axial and radial orientations
are considered with respect to the rotational axis X of the
torque-coupling device 10. The relative terms such as "axially,"
"radially," and "circumferentially" are with respect to
orientations parallel to, perpendicular to, and circularly around
the rotational axis X, respectively.
[0041] The sealed casing 12 according to the exemplary embodiment
as illustrated in FIG. 2 includes a first shell (or cover shell)
20, and a second shell (or impeller shell) 22 disposed coaxially
with and axially opposite to the first shell 20. The first and
second shells 20, 22 are non-movably (i.e., fixedly) interconnected
and sealed together about their outer peripheries, such as by weld
13. Each of the first and second shells 20, 22 are integral or
one-piece and may be made, for example, by press-forming one-piece
metal sheets.
[0042] The first shell 20 is selectively drivingly connectable to
the driving shaft, typically to the output shaft 5 of the ICE 4,
through the torsional vibration damper 18 and the SOWC 90.
Specifically, in the illustrated embodiment of FIG. 2, the casing
12 is selectively rotatably driven by the ICE 4 and is selectively
drivingly coupled to the torsional vibration damper 18 and the
driving shaft 5 through the SOWC 90.
[0043] Furthermore, the casing 12 is drivingly (non-rotatably)
connected to the output shaft 7 of the rotary electric machine 6
through a ring gear (or a sprocket) formed integrally with or
mounted to the SOWC 90, which is non-movably (i.e., fixedly)
connected to the casing 12 (such as by welding or other appropriate
means), and a continuous belt 9 (or a pinion gear), so that the
casing 12 turns at the same speed at which the rotary electric
machine 6 operates for transmitting torque.
[0044] The torque converter 14 includes an impeller wheel
(sometimes referred to as the pump, impeller assembly or impeller)
24, a turbine wheel (sometimes referred to as the turbine assembly
or turbine) 26, and a stator (sometimes referred to as the reactor)
28 interposed axially between the impeller wheel 24 and the turbine
wheel 26, as best shown in FIG. 2. The impeller wheel 24, the
turbine wheel 26, and the stator 28 are coaxially aligned with one
another and the rotational axis X. The impeller wheel 24, the
turbine wheel 26, and the stator 28 collectively form a torus. The
impeller wheel 24 and the turbine wheel 26 may be fluidly coupled
to one another in operation as known in the art. In other words,
the turbine wheel 26 is hydro-dynamically drivable by the impeller
wheel 24.
[0045] The impeller wheel 24 includes the impeller shell 22, an
annular impeller core ring 31, and a plurality of impeller blades
32 fixedly (i.e., non-moveably) attached, such as by brazing, to
the impeller shell 22 and the impeller core ring 31. The impeller
shell 22 is an integral (or unitary) component, e.g., made of a
single part or separate components fixedly connected together.
[0046] The turbine wheel 26, as best shown in FIGS. 2 and 3,
includes an annular, semi-toroidal (or concave) turbine shell 34
rotatable about the rotational axis X, an annular turbine core ring
35, and a plurality of turbine blades 36 fixedly (i.e.,
non-moveably) attached, such as by brazing, to the turbine shell 34
and the turbine core ring 35. The turbine shell 34, the turbine
core ring 35 and the turbine blades 36 are conventionally formed by
stamping from steel blanks. The impeller shell 22 and the turbine
shell 34 collectively define a toroidal inner chamber (or torus
chamber) C.sub.T therebetween. The stator 28 is positioned between
the impeller wheel 24 and the turbine wheel 26 to redirect fluid
from the turbine wheel 26 back to the impeller wheel 24 in an
efficient manner. The stator 28 is typically mounted on a one-way
(or overrunning) clutch 30 to prevent the stator 28 from
counter-rotating.
[0047] The turbine wheel 26 is non-rotatably secured to a turbine
(or output) hub 40 by appropriate means, such as by rivets,
threaded fasteners or welding. The turbine hub 40 is non-rotatably
splined to the driven shaft 8. The turbine hub 40 is rotatable
about the rotational axis X and is coaxial with the driven shaft 8
so as to center the turbine wheel 26 on the driven shaft 8.
Conventionally, the turbine blades 36 of the turbine wheel 26
interact, in a known manner, with the impeller blades 32 of the
impeller wheel 24. The stator 28 is coupled in rotation to a
stationary stator shaft 29 through the one-way (or overrunning)
clutch 30.
[0048] At low turbine shaft speeds, the impeller wheel 24 causes
hydraulic fluid to flow from the impeller wheel 24 to the turbine
wheel 26, and to flow back to the impeller wheel 24 through the
stator 28, thereby providing a first power flow path. The stator 28
is held against rotation by the one-way clutch 30, such that it can
redirect the fluid flow and provide a reaction torque for torque
multiplication. The one-way clutch 30 permits rotation of the
stator 28 in one direction only. In other words, the stator 28 is
typically mounted on the one-way clutch 30 to prevent the stator 28
from counter-rotation.
[0049] The lock-up clutch 16 of the torque-coupling device 10
includes a friction ring 42, and a dual piston assembly 44, both
axially movable to and from the cover shell 20. The friction ring
42 is axially moveable relative to the casing 12 along the
rotational axis X to and from a locking (or inner engagement)
surface 12e defined on the cover shell 20 of the casing 12, as best
shown in FIGS. 4 and 5. The friction ring 42 is configured to
selectively frictionally engage the locking surface 12e of the
cover shell 20 of the casing 12. The friction ring 42 is disposed
axially between the dual piston assembly 44 and the cover shell
20.
[0050] The dual piston assembly 44 is mounted to a cover hub 46 so
as to be rotatable relative thereto. Moreover, the dual piston
assembly 44 is axially moveable along the cover hub 46. The cover
hub 46 is non-moveably attached to the cover shell 20 by
appropriate means, such as by welding. In turn, the cover hub 46 is
slidingly mounted to the turbine hub 40 so as to be rotatably
moveable relative to the turbine hub 40.
[0051] The sealed casing 12 and the dual piston assembly 44
collectively define a hydraulically sealed apply chamber C.sub.A
between the impeller shell 22 and the dual piston assembly 44, and
a hydraulically sealed release chamber C.sub.R between the cover
shell 20, the dual piston assembly 44 and the cover hub 46. It is
known to those skilled in the art that hydrokinetic torque coupling
devices typically include a fluid pump and a control mechanism
controlling and regulating hydraulic pressure of the hydrokinetic
torque coupling device. The control mechanism regulates the
pressure in the apply chamber C.sub.A and in the release chamber
C.sub.R (i.e., on the axially opposite sides of a lockup piston)
through operation of a valve system to selectively position a
lockup piston in a desired position associated with an intended one
of the operating modes.
[0052] The friction ring 42 includes a generally radially
orientated annular friction portion 48, as best shown in FIGS. 4
and 5, and one or more driving tabs (or abutment elements) 50
extending axially outwardly from the friction portion 48 of the
friction ring 42. Moreover, the driving tabs 50 are equiangularly
and equidistantly spaced from each other. The friction ring 42 with
the friction portion 48 and the driving tabs 50 is an integral (or
unitary) part, e.g., made of a single or unitary component, but may
be separate components fixedly connected together. Preferably, the
driving tabs 50 are integrally press-formed on the friction ring
42. The friction ring 42 is drivingly engaged with the turbine
wheel 26 through the driving tabs 50 and turbine tabs 37 fixed to
an outer surface of the turbine shell 34 by appropriate means, such
as by welding. In other words, the driving tabs 50 drivingly engage
the turbine tabs 37 so that the friction ring 42 is non-rotatably
coupled to the turbine wheel 26 while being axially moveable along
the rotational axis X relative to the turbine shell 34 so as to
selectively engage the friction ring 42 against the locking surface
12e of the casing 12.
[0053] The annular friction portion 48 of the friction ring 42 has
axially opposite first and second friction faces 48.sub.1 and
48.sub.2, respectively, as best shown in FIG. 5. The first friction
face 48.sub.1 of the friction ring 42 (defining an engagement
surface of the friction ring 42) faces the locking surface 12e of
the cover shell 20 of the casing 12. An annular friction liner 49
is attached to each of the first and second friction faces 48.sub.1
and 48.sub.2 of the annular friction portion 48 of the friction
ring 42, such as by adhesive bonding, as best shown in FIG. 5.
[0054] The dual piston assembly 44 is mounted to a cover hub 46 so
as to be rotatable relative thereto. Moreover, the dual piston
assembly 44 is axially moveable along the cover hub 46. The dual
piston assembly 44 includes an annular main (or first) piston 52,
as best shown in FIGS. 4 and 5, axially movable to and from the
cover shell 20, and at least one annular secondary (or second)
piston 54 mounted to the main piston 52 and axially moveable
relative to the main piston 52. According to the exemplary
embodiment of the present invention, the dual piston assembly 44
includes a plurality of annular secondary pistons 54 spaced
circumferentially equidistantly (or equiangularly) from one another
around the rotational axis X. The friction portion 48 of the
friction ring 42 is disposed axially between the main piston 52 and
the locking surface 12e of the cover shell 20.
[0055] The main piston 52 includes a radially oriented annular
piston body 56, at least one axially protruding boss 58, and an
annular hub portion 60 having a cylindrical flange 62 that is
proximate the rotational axis X relative to the annular piston body
56 of the main piston 52. The cylindrical flange 62 of the hub
portion 60 of the main piston 52 extends axially at a radially
inner peripheral end of the hub portion 60 toward the turbine wheel
26. According to the exemplary embodiment of the present invention,
the main piston 52 includes a plurality of the axially protruding
bosses 58 spaced circumferentially equidistantly (or equiangularly)
from one another around the rotational axis X, as best shown in
FIGS. 6-8.
[0056] The cover shell 20 of the casing 12 includes at least one
axially protruding piston cup 80 formed integrally with the cover
shell 20 of the casing 12, as best shown in FIGS. 2-6. According to
the exemplary embodiment of the present invention, the cover shell
20 of the casing 12 includes a plurality of the axially protruding
piston cups 80 spaced circumferentially equidistantly (or
equiangularly) from one another around the rotational axis X, as
best shown in FIG. 6. The piston cups 80 axially protrude from the
cover shell 20 toward the secondary pistons 54. As further shown in
FIGS. 5 and 6, each of the piston cups 80 has a cylindrical inner
surface 81 extending axially parallel to the rotational axis X. The
cylindrical inner surface 81 of each of the piston cups 80
corresponds to and is configured for receiving one of the bosses
58, as best shown in FIGS. 2-5. The cover shell 20 of the casing 12
with the piston cups 80 is an integral (or unitary) component,
e.g., made of a single part, for example, by press-forming
one-piece metal sheets, or separate components fixedly connected
together.
[0057] Each of the bosses 58 axially protrudes toward the cover
shell 20 and into one of the axially protruding piston cups 80 of
the cover shell 20. As further shown in FIG. 5, each of the bosses
58 has a cylindrical inner surface 59.sub.1 and a cylindrical outer
surface 59.sub.2 both extending axially parallel to the rotational
axis X. The cylindrical inner surface 59.sub.1 of each of the
bosses 58 correspond to and are configured for receiving one of the
secondary pistons 54, as best shown in FIG. 5. The cylindrical
outer surface 59.sub.2 of each of the bosses 58 corresponds to and
is configured for being received into one of the axially protruding
piston cups 80 of the cover shell 20, as best shown in FIG. 5. The
main piston 52 with the annular body 56 and the bosses 58 is an
integral (or unitary) component, e.g., made of a single part, for
example, by press-forming one-piece metal sheets, or includes
separate components fixedly connected together.
[0058] As best shown in FIGS. 2-5, the bosses 58 of the main piston
52 are disposed radially below the friction portion 48 of the
friction ring 42. The main piston 52 is slidingly mounted to and
axially moveable relative to the cover hub 46. A radially outer
surface of the cover hub 46 includes an annular slot (or seal
groove) for receiving a sealing member, such as an O-ring 47, as
best shown in FIGS. 2-4. The sealing member (e.g., O-ring) 47
creates a seal at the interface of the main piston 52 and the cover
hub 46. As discussed in further detail below, the main piston 52 is
axially movably relative to the cover hub 46 along this interface.
The main piston 52 is non-rotatably coupled to the cover hub 46,
such as by means of a set of elastic (or flexible) tongues 89,
which are arranged substantially on one circumference, and which
are oriented tangentially between the cover hub 46 and the main
piston 52, while permitting axial displacement of the main piston
52 relative to the cover hub 46. Specifically, as best shown in
FIGS. 2-4 and 7, one free end of each of the axially flexible
tongues 89 is secured to the annular hub portion 60 of the main
piston 52, while an opposite free end of each of the elastic
tongues 89 is secured to a strap plate 88, which, in turn, is fixed
to the cover hub 46 by appropriate means, such as by welding. The
axially flexible tongues 89 are configured to transmit torque
between the main piston 52 and the cover hub 46, while allowing
axial displacement of the main piston 52 relative to the cover hub
46. In other words, the elastic tongues 89 are configured to be
deformed elastically in the axial direction to enable relative
movement of the main piston 52 relative to the cover hub 46. The
resilient tongues 89 bias the main piston 52 away from the locking
surface 12e of the cover shell 20.
[0059] The main piston 52 is axially moveable relative to the cover
shell 20 between a lockup position and a non-lockup position of the
lockup clutch 16. In the lockup position of the lockup clutch 16,
the main piston 52 non-rotatably frictionally engages the locking
surface 12e of the cover shell 20 of the casing 12. In the
non-lockup position of the lockup clutch 16, best shown in FIG. 5,
the main piston 52 is axially spaced from the locking surface 12e
of the cover shell 20 of the casing 12 and does not frictionally
engage the cover shell 20 of the casing 12. In other words, in the
lockup position of the lockup clutch 16, the main piston 52 is
non-rotatably coupled to the casing 12 so as to non-rotatably
couple the casing 12 to the turbine hub 40 through the turbine
shell 34, while in the non-lockup position of the lockup clutch 16,
the casing 12 is rotatably coupled to the turbine hub 40 through
the torque converter 14. Moreover, the strap plate 88 limits axial
movement of the main piston 52 in the direction away from the
locking surface 12e of the cover shell 20, i.e., toward the
non-lockup position of the lockup clutch 16, as best shown in FIGS.
2-4.
[0060] Further according to the exemplary embodiment of the present
invention, the secondary pistons 54 are preferably identical. Each
of the secondary pistons 54 includes a cylindrical hollow body 68
having a head member 70, a cylindrical skirt 72 defining a hollow
chamber 73 within the secondary piston 54, and a piston (or
actuator) rod 74 axially extending from the head member 70 through
the main piston 52, as best shown in FIGS. 4, 5 and 9. The
cylindrical hollow body 68 is formed unitarily with the head member
70, the cylindrical skirt 72 and the actuator rod 74, as best shown
in FIG. 5. Each of the secondary pistons 54 is axially slidably
mounted within an associated one of the bosses 58 of the main
piston 52, while each of the bosses 58 of the main piston 52 is
axially slidably mounted within an associated one of the
cylindrical piston cups 80 of the cover shell 20 of the casing 12,
as best shown in FIG. 2-5. The piston rod 74 of each of the
secondary pistons 54 axially extends through a hole 21 extending
through each of the piston cups 80 of the cover shell 20, as best
shown in FIG. 5. The secondary piston 54, with the cylindrical
hollow body 68 and the piston rod 74, is an integral (or unitary)
component, e.g., made of a single part, for example, by casting or
machining, or includes separate components fixedly connected
together.
[0061] The cylindrical skirt 72 of the cylindrical hollow body 68
of each of the secondary pistons 54 has an annular groove 84 formed
in the cylindrical skirt 72 of the hollow body 68 of each of the
secondary pistons 54, for example, by machining or casting. An
annular first piston sealing member 85 is disposed in the annular
groove 84. Each of the secondary pistons 54 is sealed within one of
the bosses 58 of the main piston 52 by the first piston sealing
member 85. According to the exemplary embodiment of the present
invention, the secondary pistons 54 are axially reciprocatingly and
sealingly moveable relative to both the main piston 52 and the
cover shell 20 of the casing 12. The first piston sealing member
85, mounted to a radially outer peripheral surface of each of the
secondary pistons 54, creates a seal at the interface of the main
piston 52 and each of the secondary pistons 54. Similarly, the
cylindrical outer surface 59.sub.2 of each of the bosses 58 is
formed with an annular groove 53 formed in the boss 58 of each of
the main piston 152, for example, by machining or casting. An
annular second piston sealing member (e.g., O-ring) 61 is disposed
in the annular groove 53. Thus, each of the secondary pistons 54 is
sealed within one of the bosses 58 of the main piston 52 by the
first piston sealing member 85, and the main piston 52 is sealed
within one of the piston cups 80 of the cover shell 20 by the
second piston sealing member 61. According to the exemplary
embodiment of the present invention, the secondary pistons 54 are
axially reciprocatingly and sealingly moveable relative to both the
main piston 52, while the main piston 52 is axially reciprocatingly
and sealingly moveable relative to the cover shell 20 of the casing
12. The first piston sealing member 85, mounted to a radially outer
peripheral surface of each of the secondary pistons 54, creates a
seal at the interface of the main piston 52 and each of the
secondary pistons 54, while the second piston sealing member 61,
mounted to a radially outer peripheral surface of each of the
bosses 58 of the main piston 52, creates a seal at the interface of
the main piston 52 and each of the piston cups 80 of the cover
shell 20.
[0062] Moreover, each of the secondary pistons 54 is axially biased
by at least one compression spring (such as a coil spring) 78 away
from the cover shell 20 of the casing 12, as best shown in FIGS.
2-5. The compression spring 78 is disposed within the hollow
chamber 73 of the secondary piston 54 between the head member 70 of
the secondary piston 54 and a radial wall 82 of the piston cup 80
of the cover shell 20. A free distal end 75 of the piston rod 74 is
provided with a snap ring 77, for example, disposed outside of the
cover shell 20 for limiting axial movement of the secondary piston
54 in the direction toward the turbine wheel 26 and away from the
cover shell 20 when the snap ring 77, mounted on the piston rod 74
of the secondary piston 54, engages the radial wall 82 of the
piston cup 80 of the cover shell 20. The piston rod 74 of the
secondary piston 54 has an annular groove 71 (best shown in FIG. 9)
formed therein into which the snap ring 77 is received. The free
distal end 75 of the piston rod 74 has an outermost conical part
76k, and an inner cylindrical part 76c adjacent to the snap ring 77
and located between the annular groove 71 and the outermost conical
part 76k, as best shown in FIG. 9. Each of the secondary pistons 54
is axially moveable relative to the main piston 52 and the piston
cup 80 of the cover shell 20 between an extended position and a
retracted position with respect to the main piston 52.
[0063] In the extended position, best shown in FIGS. 2-5 and
13-18B, the secondary piston 54 extends into a bore of the axially
protruding boss 58 of the main piston 52 away from the radial wall
82 of the piston cup 80 of the cover shell 20, so that the snap
ring 77 on the piston rod 74 of the secondary piston 54 engages the
radial wall 82 of the piston cup 80 of the cover shell 20.
Moreover, the compression spring 78 biases the secondary pistons 54
to the extended position.
[0064] In the retracted position, best shown in FIGS. 21-24, the
secondary pistons 54 are retracted into the piston cup 80 of the
cover shell 20 toward the radial wall 82 of the piston cup 80, so
that the snap rings 77 on the piston rods 74 of the secondary
pistons 54 are axially spaced away from the radial wall 82 of the
piston cup 80 of the cover shell 20 toward the selective clutch
18.
[0065] The torsional vibration damper 18 includes an input (or
drive) member 64, a plurality of circumferentially acting elastic
members (springs) 65, and an output (or driven) member 66
elastically coupled to the drive member 64 through the elastic
members 65. The drive member 64 is fixed to the crankshaft 5 of the
ICE 4 by appropriate means, such as by mechanical fasteners or
welding. The driven member 66 is connected to the casing 12 through
the SOWC 90. The elastic members 65 are disposed in series relative
to each other between the drive member 64 and the driven member 66,
as best shown in FIG. 4.
[0066] The selectable one-way clutch (SOWC) 90 disposed between the
output shaft 5 of the ICE and the cover shell 20 selectively
drivingly connects the casing 12 of the hydrokinetic
torque-coupling device 10 to the crankshaft 5 of the ICE 4 through
the torsional vibration damper 18. Moreover, the SOWC 90 is
disposed outside of the casing 12 and is mounted to the support
boss 23 of the cover shell 20 through a bearing 91, as best shown
in FIGS. 2 and 3. The SOWC 90 comprises an outer race 92, an inner
race 94, a plurality of torque transmitting elements disposed
radially between the outer race 92 and the inner race 94. According
to the exemplary embodiment of the present invention, the torque
transmitting elements are in the form of first and second rollers
(such as cylindrical rollers) 96.sub.1 and 96.sub.2, respectively,
arranged in pairs in a radial gap between the outer race 92 and the
inner race 94. In other words, the SOWC 90 comprises a plurality of
pairs of first and second rollers 96.sub.1 and 96.sub.2 arranged in
pairs and disposed radially between the outer race 92 and the inner
race 94 and contactable with both the outer and inner races 92,
94.
[0067] The outer race 92 includes a radially inner surface 93
defining an outer raceway of the SOWC 90 as is known in the art of
roller one-way roller clutches. The outer race 92 of the SOWC 90 is
non-rotatably secured (i.e., fixed) to the cover shell 20 by an
appropriate means, such as a weld 101, as best shown in FIGS. 3 and
5. In other words, the outer race 92 of the SOWC 90 is
non-rotatable relative to the casing 12. Moreover, a radially outer
annular peripheral surface of the outer race 92 has multiple radial
outer teeth (or splines) 112 (as best shown in FIGS. 10 and 11)
configured to be engaged by the continuous belt 9 (or pinion gear),
as shown in FIG. 1.
[0068] The radially inner surface 93 of the outer race 92 includes
a plurality of evenly circumferentially spaced first and second cam
ramps 95.sub.1 and 95.sub.2, respectively, arranged in pairs.
Moreover, the number of pairs of the first and second cam ramps
95.sub.1 and 95.sub.2 corresponds to a number of pairs of the first
and second rollers 96.sub.1 and 96.sub.2. As best shown in FIGS.
11, 13, 15, 16, 17 and 18A, the pairs of the cam ramps 95.sub.1 and
95.sub.2 are circumferentially separated by spacing blocks 97
radially inwardly extending from the inner surface 93 of the outer
race 92, while the first and second cam ramps 95.sub.1 and 95.sub.2
of each of the pairs of the cam ramps 95.sub.1 and 95.sub.2 are
circumferentially separated by a separator 98 also radially
inwardly extending from the inner surface 93 of the outer race 92.
As further illustrated in FIGS. 10 and 11, both the spacing blocks
97 and the separator 98 are formed integrally with the outer race
92.
[0069] The first and second rollers 96.sub.1 and 96.sub.2 of each
of the pairs of the first and second rollers 96.sub.1 and 96.sub.2
are biased by corresponding first and second roller springs
99.sub.1 and 99.sub.2, respectively, against the first and second
cam ramps 95.sub.1 and 95.sub.2, respectively. The first and second
roller springs 99.sub.1 and 99.sub.2 of each pair of the first and
second rollers 96.sub.1 and 96.sub.2 are circumferentially
separated by the separator 98, as best shown in FIG. 10.
[0070] The inner race 94 includes a cylindrical radially inner
raceway 100 coaxial with the rotational axis X. Also, the inner
race 94 of the SOWC 90 is mounted to the support boss 23 of the
cover shell 20 through the bearing 91, as best shown in FIGS. 2 and
3. In other words, the inner race 94 of the SOWC 90 is rotatable
relative to the casing 12. Moreover, the driven member 66 of the
torsional vibration damper 18 is non-moveably attached to the inner
race 94 of the SOWC 90 by appropriate means, such as by fasteners
or a weld 67, as best shown in FIGS. 4 and 5.
[0071] The first and second rollers 96.sub.1 and 96.sub.2 of each
pair of the rollers are biased by the first and second roller
springs 99.sub.1 and 99.sub.2 into engagement with the first and
second cam ramps 95.sub.1 and 95.sub.2, respectively, on the inner
surface 93 of the outer race 92. As a result, the first and second
rollers 96.sub.1 and 96.sub.2 become wedged (or jammed) between the
first and second cam ramps 95.sub.1 and 95.sub.2, respectively, of
the outer race 92 and the inner raceway 100 of the inner race 94,
and non-rotatably couple (or lock) the outer race 92 and the inner
race 94 together to rotate as a unit. In other words, the first and
second rollers 96.sub.1 and 96.sub.2 are moveable along the first
and second cam ramps 95.sub.1 and 95.sub.2, respectively, between
an engaged position, when the first and second rollers 96.sub.1 and
96.sub.2 are wedged between the first and second cam ramps 95.sub.1
and 95.sub.2, respectively, of the outer race 92 and the inner
raceway 100 of the inner race 94 due to a biasing force of the
first and second roller springs 99.sub.1 and 99.sub.2,
respectively, and into a disengaged position when the first and
second rollers 96.sub.1 and 96.sub.2 are displaced against the
biasing force of one of the first and second roller springs
99.sub.1 and 99.sub.2, and are not wedged between the first and
second cam ramps 95.sub.1 and 95.sub.2, respectively, of the outer
race 92 and the inner raceway 100 of the inner race 94. Moreover,
the first and second rollers 96.sub.1 and 96.sub.2 are so arranged
that one of the first and second rollers 96.sub.1 and 96.sub.2 of
each pair of rollers 96.sub.1, 96.sub.2 operates to prevent
relative rotation of the inner and outer races 94, 92 in one
direction and the other one of the first and second rollers
96.sub.1 and 96.sub.2 of each pair of rollers 96.sub.1, 96.sub.2
prevents relative rotation of the inner and outer races 94, 92 in
the opposite direction.
[0072] The SOWC 90 further comprises a plurality of actuator
members 102, each operatively associated with one pair of the first
and second rollers 96.sub.1 and 96.sub.2. Specifically, each of the
actuator members 102 is configured to be in contact with the first
roller 96.sub.1 of one pair of the first and second rollers
96.sub.1 and 96.sub.2, as best shown in FIGS. 13 and 15-18A.
According to the exemplary embodiment of the present invention, the
actuator members 102 are preferably structurally and functionally
identical. Moreover, the number of the actuator members 102
corresponds to the number of the secondary pistons 54 of the dual
piston assembly 44 and to the number of pairs of the first and
second rollers 96.sub.1 and 96.sub.2. Furthermore, as best shown in
FIGS. 12 and 14, each of the actuator members 102 includes a
concave support portion 104 adjacent to and configured to engage an
annular outer peripheral surface of the first roller 96.sub.1, and
an actuator portion 106 outwardly extending from the concave
support portion 104 away from the first roller 96.sub.1 and toward
the adjacent spacing block 97.
[0073] Each of the actuator members 102 is configured to cooperate
with one of the secondary pistons 54 of the dual piston assembly
44. Specifically, the actuator portion 106 of each of the actuator
members 102 has an actuator edge 107 configured to engage the free
distal end 75 of the piston rod 74 of the secondary pistons 54, as
best shown in FIGS. 5, 13, 14 and 15. Also, each of the actuator
members 102 is circumferentially displaceable along the outer
raceway 93 of the outer race 92 and the inner raceway 100 of the
inner race 94. Moreover, the outer raceway 93 of the outer race 92
is formed with a plurality of arc-shaped guide grooves 108, each
having a stopping end 109 configured to limit circumferential
displacement of the actuator members 102 in the direction away from
the separators 98 and toward the spacing blocks 97 to allow the
first roller 96.sub.1 to move to the engaged position thereof.
Specifically, the circumferential displacement of the actuator
members 102 is stopped when the actuator edges 107 of the actuator
members 102 engage the stopping ends 109 of the arc-shaped guide
grooves 108.
[0074] Moreover, the secondary pistons 54 of the dual piston
assembly 44 are configured to circumferentially displace the
actuator members 102 along the inner raceway 100 of the inner race
94. Consequently, the actuator members 102 circumferentially
displace the first rollers 96.sub.1 against the action of the
corresponding first roller springs 99.sub.1 out of the engaged
position (i.e., wedging engagement) with the first cam ramps
95.sub.1 of the outer race 92 and retain the first rollers 96.sub.1
in the disengaged position.
[0075] As best illustrated in FIGS. 5, 13, 14 and 15, when the
secondary pistons 54 are in the extended positions, the actuator
edges 107 of the actuator portions 106 of the actuator members 102
engage the conical parts 76k of the free distal ends 75 of the
piston rods 74 of the secondary pistons 54 near tips of the piston
rods 74. In the extended position of the secondary pistons 54, the
actuator members 102 are not displaced by the piston rods 74. Thus,
the first rollers 96.sub.1 are in the engaged position thereof,
i.e., in narrow ends of the first cam ramps 95.sub.1. Moreover,
when the secondary pistons 54 are in the extended positions, the
SOWC 90 is in a deactivated state (illustrated in FIGS. 5 and
13-18B) and configured to transmit torque in both (clockwise and
counterclockwise) rotational directions.
[0076] When the secondary pistons 54 move to the retracted
position, the conical parts 76k of the free distal ends 75 of the
piston rods 74 of the secondary pistons 54 displace the actuator
members 102 away from the narrow ends of the first cam ramps
95.sub.1. In turn, the concave support portions 104 of the actuator
members 102 push the first roller 96.sub.1 away from the narrow
ends of the first cam ramps 95.sub.1 to the disengaged position so
that the first rollers 96.sub.1 cannot jam between the outer and
inner races 92, 94 of the SOWC 90. Thus, the secondary pistons 54
of the dual piston assembly 44 act as actuators of the SOWC 90.
[0077] When the secondary pistons 54 reach the retracted position
(i.e., when the secondary pistons 54 is in a right innermost
position shown in FIGS. 23, 24 and 26), the actuator edges 107 of
the actuator portions 106 of the actuator members 102 engage the
inner cylindrical part 76c of the free distal ends 75 of the piston
rods 74 of the secondary pistons 54 near tips of the piston rods
74. When the secondary pistons 54 are in the retracted positions,
the first rollers 96.sub.1 are in the disengaged position so that
the first rollers 96.sub.1 cannot jam between the outer and inner
races 92, 94 of the SOWC 90. Accordingly, the SOWC 90 is in an
activated state and configured to transmit torque only in one
(counterclockwise in FIG. 13) rotational direction and freewheel in
the opposite (clockwise in FIG. 13) rotational direction.
[0078] The compression spring 78 of each of the secondary pistons
54 is sized to resist fluid pressure of 500 KPa. In other words,
when the fluid pressure in the apply chamber C.sub.A is equal to or
more than 500 KPa, the secondary pistons 54 move rightward in the
direction of FIGS. 2-5 toward the cover shell 20 of the casing 12
and circumferentially displace the first rollers 96.sub.1 of the
SOWC 90 to the disengaged position by means of the actuator members
102. Those skilled in the art will recognize that pressures other
than 500 KPa may be used, depending upon the design.
[0079] The hydrokinetic torque-coupling device 10 in accordance
with the present invention has four modes of operation.
[0080] In a first mode of operation, illustrated in FIGS. 2-5, a
release pressure of the lock-up clutch 16 in the release chamber
C.sub.R is about 500 KPa, while an apply pressure of the lock-up
clutch 16 in the apply chamber C.sub.A is about 200 KPa.
Consequently, the main piston 52 is in the non-lockup position and
the secondary pistons 54 are in the extended position, in which
both the main piston 52 and the secondary pistons 54 are spaced
from the cover shell 20 to the maximum distance, so that the
friction portion 48 of the friction ring 42 does not frictionally
engage the locking surface 12e of the cover shell 20 of the casing
12 by the main piston 52 (i.e., the non-lockup position of the
lock-up clutch 16), and the SOWC 90 is in the deactivated state
(illustrated in FIGS. 5 and 13-18B). In the first mode of
operation, the main piston 52 is axially spaced from the friction
ring 42, and the torque-coupling device 10 is in a hydrodynamic
mode with the ICE 4 drivingly coupled thereto through the SOWC 90
and the torsional vibration damper 18.
[0081] In a second mode of operation, illustrated in FIGS. 19-20,
the apply pressure of the lock-up clutch 16 in the apply chamber
C.sub.A is between 0-500 KPa, preferably between 100-500 KPa.
Consequently, the main piston 52 moves toward the cover shell 20
against the resilient force of the tongues 89 toward the lockup
position, in which the main piston 52 presses against the friction
portion 48 of the friction ring 42 to frictionally non-rotatably
engage the friction ring 42 against the locking surface 12e of the
cover shell 20 of the casing 12 (i.e., the lockup position of the
lock-up clutch 16). The secondary pistons 54 remain in the extended
position, in which the SOWC 90 is in the deactivated state. In the
second mode of operation, the ICE 4 and the transmission shaft 8
are directly connected. In the second mode of operation a battery
of the hybrid vehicle may be in a charging mode.
[0082] In a third mode of operation, illustrated in FIGS. 21-22,
the apply pressure of the lock-up clutch 16 in the apply chamber
C.sub.A is between 500-800 KPa. Consequently, the secondary pistons
54 move rightward in the direction toward the cover shell 20 of the
casing 12 and the SOWC 90 to the retracted position, and place the
SOWC 90 in the activated state. Specifically, the free distal ends
75 of the piston rods 74 push the actuator members 102 away from
the narrow ends of the first cam ramps 95.sub.1. In turn, the
concave support portions 104 of the actuator members 102 push the
first roller 96.sub.1 away from the narrow ends of the first cam
ramps 95.sub.1 against the resilient force of the first roller
springs 99.sub.1 to the disengaged position so that the first
rollers 96.sub.1 cannot jam between the outer and inner races 92,
94 of the SOWC 90, and place the SOWC 90 in the activated state.
The main piston 52 remains in the lockup position. In the third
mode of operation, the ICE 4 and the casing 12 of the hydrokinetic
torque-coupling device 10 (thus the transmission shaft 8) are
disconnected, while the electric machine 6 and the transmission
shaft 8 are directly connected. The ICE 4 may be off. The hybrid
vehicle is in re-generation mode or an electric-drive (or E-drive)
mode.
[0083] In a fourth mode of operation, illustrated in FIGS. 25 and
26, the release pressure of the lock-up clutch 16 in the release
chamber C.sub.R is about 800 KPa, and the apply pressure of the
lock-up clutch 16 in the apply chamber C.sub.A is also about 800
KPa. Consequently, the secondary pistons 54 remain in the retracted
position and maintain the SOWC 90 in the activated state. However,
the main piston 52 moves leftward (as illustrated in FIGS. 25 and
26) away from the cover shell 20 of the casing 12 to the non-lockup
position of the lock-up clutch 16. In the fourth mode of operation,
the ICE 4 is on and ready to switch to the first mode of
operation.
[0084] Various modifications, changes, and alterations may be
practiced with the above-described embodiment, including but not
limited to the additional embodiments shown in FIGS. 2-26.
[0085] The foregoing description of the exemplary embodiments of
the present invention has been presented for the purpose of
illustration in accordance with the provisions of the Patent
Statutes. It is not intended to be exhaustive or to limit the
invention to the precise forms disclosed. The embodiments disclosed
hereinabove were chosen in order to best illustrate the principles
of the present invention and its practical application to thereby
enable those of ordinary skill in the art to best utilize the
invention in various embodiments and with various modifications as
suited to the particular use contemplated, as long as the
principles described herein are followed. This application is
therefore intended to cover any variations, uses, or adaptations of
the invention using its general principles. Further, this
application is intended to cover such departures from the present
disclosure as come within known or customary practice in the art to
which this invention pertains. Thus, changes can be made in the
above-described invention without departing from the intent and
scope thereof. It is also intended that the scope of the present
invention be defined by the claims appended thereto.
* * * * *