U.S. patent application number 16/369842 was filed with the patent office on 2020-06-11 for apparatus for torque vectoring.
This patent application is currently assigned to Hyundai Motor Company. The applicant listed for this patent is Hyundai Motor Company Kia Motors Corporation. Invention is credited to Chulmin AHN, SungGon BYUN, Junyoung HA, Baekyu KIM, Seok Joon KIM, Hongkyu LEE, Su Hyeon MAENG.
Application Number | 20200182342 16/369842 |
Document ID | / |
Family ID | 70972426 |
Filed Date | 2020-06-11 |
United States Patent
Application |
20200182342 |
Kind Code |
A1 |
AHN; Chulmin ; et
al. |
June 11, 2020 |
APPARATUS FOR TORQUE VECTORING
Abstract
A drive torque received from a power source is split and output
to first and second output shafts through a torque vectoring
apparatus including a torque vectoring device that controls a
torque ratio of split torques, where the torque vectoring device
includes a control motor, a first compound planetary gear set
including first and second planetary gear sets having a first
rotation element fixed to a housing, a shared second rotation
element connected to the first output shaft, and a third rotation
element, and a second compound planetary gear set including third
and fourth planetary gear sets having a shared fourth rotation
element connected to the second output shaft, a fifth rotation
element connected to a third rotation element, and a sixth rotation
element connected to the control motor.
Inventors: |
AHN; Chulmin; (Suwon-si,
KR) ; BYUN; SungGon; (Hwaseong-si, KR) ; KIM;
Seok Joon; (Yongin-si, KR) ; MAENG; Su Hyeon;
(Seoul, KR) ; LEE; Hongkyu; (Yongin-si, KR)
; KIM; Baekyu; (Hwaseong-si, KR) ; HA;
Junyoung; (Ulsan, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Hyundai Motor Company
Kia Motors Corporation |
Seoul
Seoul |
|
KR
KR |
|
|
Assignee: |
Hyundai Motor Company
Seoul
KR
Kia Motors Corporation
Seoul
KR
|
Family ID: |
70972426 |
Appl. No.: |
16/369842 |
Filed: |
March 29, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F16H 3/725 20130101;
F16H 48/36 20130101; F16H 2048/368 20130101; F16H 2048/364
20130101 |
International
Class: |
F16H 48/36 20060101
F16H048/36; F16H 3/72 20060101 F16H003/72 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 5, 2018 |
KR |
10-2018-0155484 |
Claims
1. A torque vectoring apparatus receiving a vehicle driving torque
from a motor/generator, the torque vectoring apparatus comprising:
a speed reduction device coupled to the motor/generator and
reducing a rotation speed received from the motor/generator; a
differential device coupled to the speed reduction device and
receiving a reduced rotation speed from the speed reduction device
and differentially outputting split torques to first-side and
second-side output shafts; and a torque vectoring device coupled to
the differential device and controlling a torque ratio of the split
torques output to the first-side and second-side output shafts
coupled to the torque vectoring device, wherein the torque
vectoring device includes: a torque vectoring control motor; a
first compound planetary gear set including: a first planetary gear
set having a first rotation element and a second rotation element;
and a second planetary gear set sharing the second rotation element
with the first planetary gear set and having a third rotation
element, wherein the first rotation element is fixed to a housing
and the second rotation element is fixedly connected to a first
output shaft among the first-side and second-side output shafts
through the differential device; and a second compound planetary
gear set including: a third planetary gear set having a fourth
rotation element and a fifth rotation element; and a fourth
planetary gear set sharing the fourth rotation element with the
third planetary gear set and having a sixth rotation element,
wherein the fourth rotation element is fixedly connected to a
second output shaft among the first-side and second-side output
shafts, the fifth rotation element is fixedly connected to the
third rotation element, and the sixth rotation element is
gear-engaged with the torque vectoring control motor.
2. The torque vectoring apparatus of claim 1, wherein an output
gear formed at a motor shaft of the torque vectoring control motor
is gear-engaged with an input gear fixedly connected to the sixth
rotation element.
3. The torque vectoring apparatus of claim 1, wherein the torque
vectoring control motor is formed as a motor of which rotation
speed and rotating direction are controllable.
4. The torque vectoring apparatus of claim 1, wherein the first
rotation element, the second rotation element and the third
rotation element of the first compound planetary gear set are
formed by a first sun gear of the first planetary gear set, a first
common planet carrier shared by the first and second planetary gear
sets, and a second ring gear of the second planetary gear set,
respectively; and wherein the fourth rotation element, the fifth
rotation element, and the sixth rotation element of the second
compound planetary gear set are formed by a second common planet
carrier shared by the third and fourth planetary gear sets, a third
ring gear of the third planetary gear set, and a fourth sun gear of
the fourth planetary gear set, respectively.
5. The torque vectoring apparatus of claim 1, wherein the
differential device includes a fifth planetary gear set having a
seventh rotation element, an eighth rotation element, and a ninth
rotation element; wherein the seventh rotation element is fixedly
connected to the second output shaft fixedly connected to the
fourth rotation element; wherein the eighth rotation element is
fixedly connected to the first output shaft; and wherein the ninth
rotation element receives the reduced rotation speed from the speed
reduction device.
6. The torque vectoring apparatus of claim 5, wherein the fifth
planetary gear set is a double pinion planetary gear set having a
fifth sun gear, a fifth planet carrier, and a fifth ring gear as
the seventh rotation element, the eighth rotation element, and the
ninth rotation element, respectively.
7. The torque vectoring apparatus of claim 5, wherein the speed
reduction device includes: a drive gear connected to a rotor of the
motor/generator; a driven gear formed on an external circumference
of the ninth rotation element of the differential device; and an
idle gear unit coupled to the drive gear and the driven gear and
reducing an input speed received from the drive gear and outputting
the reduced rotation speed through the driven gear.
8. The torque vectoring apparatus of claim 7, wherein the idle gear
unit includes: an idle shaft mounted external to the differential
device and in parallel with the first-side and second-side output
shafts; an idle input gear rotatably mounted on the idle shaft and
gear-engaged with the drive gear; and an idle output gear fixedly
formed on the idle shaft and gear-engaged with the driven gear.
9. The torque vectoring apparatus of claim 8, wherein the idle gear
unit further including a synchronizer mounted between the idle
input gear and the idle shaft, and selectively synchronizing the
idle input gear to the idle shaft.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] The present application claims priority to Korean Patent
Application No. 10-2018-0155484 filed on Dec. 5, 2018, the entire
contents of which is incorporated herein for all purposes by this
reference.
BACKGROUND OF THE INVENTION
Field of the Invention
[0002] The present invention relates to a torque vectoring
apparatus.
Description of Related Art
[0003] In general, a torque vectoring apparatus is a device that
can independently control torques transmitted to left-side and
right-side drive wheels to improve agility and handing performance
of a vehicle.
[0004] Here, the term "torque vectoring" refers to controlling the
magnitude and the direction of an overall torque applied to a
vehicle, of which an example is that a distribution ratio of a
driving torque output from an engine and supplied to drive wheels
is controlled, facilitating respective driving wheels to receive
driving torques controlled by the torque vectoring technology.
[0005] Such a torque vectoring may be realized as an additional
function of a differential device that receives an engine torque
and distributes the engine torque to left-side and right-side drive
wheels.
[0006] A differential device provided with the torque vectoring
function may actively control a torque distribution ratio of
left-side and right-side drive wheels to satisfy intention of a
driver or to enhance dynamics of a vehicle depending on driving
circumstances.
[0007] Being assisted by such a differential device having the
torque vectoring function, a driver may better utilize the driving
torque depending on the driving circumstances and an enhancement of
vehicle dynamics may be expected.
[0008] Developing a differential device having such a torque
vectoring function is not technically obvious, since the torque
vectoring function of controlling torques supplied to respective
wheels may be additionally employed to the basic function of a
differential device.
[0009] Development of a torque vectoring apparatus is gathering
more spotlight in connection with an electric vehicle since the
electric vehicle is better applicable with such a torque vectoring
apparatus more precisely in comparison with a traditional internal
combustion engine (ICE) vehicle. As environmental vehicles become
to have more power and performance, a torque vectoring apparatus is
more spotlighted as a technology applicable to a rear differential
device of, e.g., an all wheel drive (AWD) electric vehicles (EV) to
improve cornering performance of high performance environmental
vehicles.
[0010] An exemplary environmental vehicle of the AWD electric
vehicle is not necessarily required to have a transfer shaft which
is normally required in an ICE vehicle to deliver torque from a
frontally disposed internal combustion engine to a rear drive
wheels, since AWD function may be achieved by merely employing two
motor system, i.e., front and rear motors.
[0011] Regardless of one motor or two motor system or 2wd or AWD
system, a torque of an electric motor provided in an electric
vehicle is typically more precisely controlled in comparison with
an ICE, and thus, a torque vectoring apparatus coupled with such a
drive motor may become a very potential tool to provide more
agility and more stability to a vehicle.
[0012] The information disclosed in this Background of the
Invention section is only for enhancement of understanding of the
general background of the invention and may not be taken as an
acknowledgement or any form of suggestion that this information
forms the prior art already known to a person skilled in the
art.
BRIEF SUMMARY
[0013] Various aspects of the present invention are directed to
providing a torque vectoring apparatus facilitating better
performance and less torque loss.
[0014] An exemplary torque vectoring apparatus according to an
exemplary embodiment of the present invention receives a vehicle
driving torque from a motor/generator, and may include a speed
reduction device reducing a rotation speed received from the
motor/generator, a differential device receiving the reduced
rotation speed from the speed reduction device and differentially
outputting split torques to left-side and right-side output shafts,
and a torque vectoring device controlling a torque ratio of the
split torques output to the left-side and right-side output shafts.
The torque vectoring device may include a torque vectoring control
motor, a first compound planetary gear set including first and
second planetary gear sets, and a second compound planetary gear
set including third and fourth planetary gear sets.
[0015] The first planetary gear set may include first and second
rotation elements. The second planetary gear set shares the second
rotation element with the first planetary gear set and may further
include a third rotation element. The first rotation element is
fixed to a housing. The second rotation element is fixedly
connected to a first output shaft among the left-side and
right-side output shafts through the differential device.
[0016] The third planetary gear set may include fourth and fifth
rotation elements. The fourth planetary gear set shares the fourth
rotation element with the third planetary gear set and may further
include a sixth rotation element. The fourth rotation element
fixedly connected to a second output shaft among the left-side and
right-side output shafts. The fifth rotation element is fixedly
connected to the second rotation element. The sixth rotation
element is gear-meshed with the torque vectoring control motor.
[0017] An output gear formed at a motor shaft of the torque
vectoring control motor may be externally gear-meshed with an input
gear fixedly connected to the sixth rotation element.
[0018] The torque vectoring control motor may be formed as a motor
of which rotation speed and rotating direction are
controllable.
[0019] The first, second, and third rotation elements of the first
compound planetary gear set may be formed by a first sun gear of
the first planetary gear set, a first common planet carrier shared
by the first and second planetary gear sets, and a second ring gear
of the second planetary gear set, respectively.
[0020] The fourth, fifth, and sixth rotation elements of the second
compound planetary gear set may be formed by a second common planet
carrier shared by the third and fourth planetary gear sets, a third
ring gear of the third planetary gear set, and a fourth sun gear of
the fourth planetary gear set, respectively.
[0021] The differential device may include a fifth planetary gear
set having seventh, eighth, and ninth rotation elements. The
seventh rotation element may be fixedly connected to the second
output shaft fixedly connected to the fourth rotation element. The
eighth rotation element may be fixedly connected to the first
output shaft. The ninth rotation element may receive the reduced
rotation speed from the speed reduction device.
[0022] The fifth planetary gear set may be a double pinion
planetary gear set having a fifth sun gear, a fifth planet carrier,
and a fifth ring gear respectively as the seventh, eighth, and
ninth rotation elements.
[0023] The speed reduction device may include a drive gear
connected to a rotor of the motor/generator, a driven gear formed
on an external circumference of the ninth rotation element of the
differential device, and an idle gear unit reducing an input speed
received from the drive gear and outputting the reduced rotation
speed through the driven gear.
[0024] The idle gear unit may include an idle shaft disposed
radially external to the differential device and in parallel with
the left-side and right-side output shafts, an idle input gear
rotatably mounted on the idle shaft and externally gear-meshed with
the drive gear, and an idle output gear fixedly formed on the idle
shaft and externally gear-meshed with the driven gear.
[0025] The idle gear unit may further include a synchronizer
disposed between the idle input gear and the idle shaft, and
selectively synchronizing the idle input gear to the idle
shaft.
[0026] A torque vectoring apparatus according to an exemplary
embodiment of the present invention is applicable to a high
performance environmental vehicle provided with a one-motor e-AWD
(all wheel drive), and may achieve both cornering performance and
stability of a vehicle depending on driving conditions.
[0027] Furthermore, when a vehicle speed becomes excessive to the
motor/generator MG, torque transmission from and to the
motor/generator MG may be disconnected, reducing undesired power
loss and improving fuel consumption.
[0028] Such a torque disconnection function may be applicable to a
hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle
(PHEV), and may be useful in disconnecting torque of a drive motor
in the case of running an internal combustion engine.
[0029] By employing a torque vectoring control motor TVCM in a
torque vectoring device, a torque vectoring function may be
optimally controlled, and power loss may be minimized, improving
fuel consumption characteristic. By symmetrically forming two
compound planetary gear sets in the torque vectoring device, power
loss of a torque vectoring apparatus may be minimized and
controllability of the torque vectoring apparatus is maximized,
since the torque vectoring control motor TVCM may be merely
stationary in a straight line.
[0030] Other effects which may be obtained or are predicted by an
exemplary embodiment of the present invention will be explicitly or
implicitly described in a detailed description of the present
invention. That is, various effects that are predicted according to
an exemplary embodiment of the present invention will be described
in the following detailed description.
[0031] The methods and apparatuses of the present invention have
other features and advantages which will be apparent from or are
set forth in more detail in the accompanying drawings, which are
incorporated herein, and the following Detailed Description, which
together serve to explain certain principles of the present
invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0032] FIG. 1 is a schematic diagram of a torque vectoring
apparatus according to an exemplary embodiment of the present
invention.
[0033] FIG. 2A, FIG. 2B, and FIG. 2C are lever diagrams
illustrating torque vectoring operation of the torque vectoring
apparatus according to the exemplary embodiment of the present
invention.
[0034] It may be understood that the appended drawings are not
necessarily to scale, presenting a somewhat simplified
representation of various features illustrative of the basic
principles of the invention. The specific design features of the
present invention as disclosed herein, including, for example,
specific dimensions, orientations, locations, and shapes will be
determined in part by the particularly intended application and use
environment.
[0035] In the figures, reference numbers refer to the same or
equivalent parts of the present invention throughout the several
figures of the drawing.
DETAILED DESCRIPTION
[0036] Reference will now be made in detail to various embodiments
of the present invention(s), examples of which are illustrated in
the accompanying drawings and described below. While the
invention(s) will be described in conjunction with exemplary
embodiments of the present invention, it will be understood that
the present description is not intended to limit the invention(s)
to those exemplary embodiments. On the other hand, the invention(s)
is/are intended to cover not only the exemplary embodiments of the
present invention, but also various alternatives, modifications,
equivalents and other embodiments, which may be included within the
spirit and scope of the invention as defined by the appended
claims.
[0037] Hereinafter, an exemplary embodiment of the present
invention will be described in detail with reference to the
accompanying drawings.
[0038] The drawings and description are to be regarded as
illustrative in nature and not restrictive, and like reference
numerals designate like elements throughout the specification.
[0039] In the following description, dividing names of components
into first, second and the like is to divide the names because the
names of the components are the same as each other and an order
thereof is not particularly limited.
[0040] FIG. 1 is a schematic diagram of a torque vectoring
apparatus according to an exemplary embodiment of the present
invention.
[0041] Referring to FIG. 1, a torque vectoring apparatus according
to an exemplary embodiment of the present invention includes a
motor/generator MG as a driving power source, a speed reduction
device 10, a differential device 20, and a torque vectoring device
30. The differential device 20 and the torque vectoring device 30
are disposed on an axis of left-side and right-side output shafts
OS1 and OS2.
[0042] In the torque vectoring apparatus, a rotation speed of the
motor/generator MG is reduced in the speed reduction device 10, and
the reduced rotation speed is transmitted to the differential
device 20. The differential device 20 receives a torque from the
speed reduction device 10 to and transmits the received torque to
left-side and right-side drive wheels while absorbing a speed
difference between the left-side and right-side drive wheels.
[0043] The torque vectoring device 30 adjusts a torque ratio split
to the left-side and right-side drive wheels according to driving
conditions such as turning or driving in a straight line, and
thereby improves driving performance such as a cornering turning
performance and the like of a vehicle.
[0044] The left-side and right-side output shafts OS1 and OS2 are
power transmission shafts provided between the differential device
20 and the left-side and right-side drive wheels, and may imply
typical left-side and right driveshafts.
[0045] The motor/generator MG includes a stator ST fixed to a
housing H and a rotor RT connected to the speed reduction device
10. The motor/generator MG acts as a motor supplying rotational
power to the speed reduction device 10, and also as a generator
generating electricity by the torque applied from the left-side and
right-side drive wheels.
[0046] The speed reduction device 10 receives a torque from the
motor/generator MG, and outputs a torque with a reduced rotation
speed (i.e., with an increased torque) to the differential device
20.
[0047] The speed reduction device 10 includes a drive gear DG, a
driven gear PG, and an idle gear unit IDGU. The torque of the
motor/generator MG is input to the speed reduction device 10
through the drive gear DG, and is reduced at the idle gear unit
IDGU. The reduced torque is output from speed reduction device 10
through the driven gear PG, and is transmitted to the differential
device 20.
[0048] The drive gear DG is fixedly connected to the rotor RT of
the motor/generator MG through a hub 3.
[0049] The driven gear PG is formed on one rotation element of the
differential device 20 and enables torque transmission between the
speed reduction device 10 and the differential device 20.
[0050] The idle gear unit IDGU reduces the rotation speed through
two idle gears mounted on an idle shaft IDS.
[0051] That is, the idle shaft IDS is disposed radially external to
the differential device 20, and in parallel with the left-side and
right-side output shafts OS1 and OS2.
[0052] Two idle gears are formed on the idle shaft IDS and may
include an idle input gear IDG1 and an idle output gear IDG2.
[0053] The idle input gear IDG1 is rotatably mounted on the idle
shaft IDS and is externally gear-meshed with the drive gear DG.
[0054] The idle output gear IDG2 is fixedly formed on the idle
shaft IDS and is externally gear-meshed with the driven gear
PG.
[0055] The idle gear unit IDGU further includes a synchronizer SL
on the idle shaft IDS, to selectively synchronize the idle input
gear IDG1 with the idle shaft IDS, to connect or disconnect torque
transmission between the motor/generator MG and the differential
device 20.
[0056] The synchronizer SL is disposed between the idle input gear
IDG1 and the idle shaft IDS, and selectively synchronizes the idle
input gear IDG1 to the idle shaft IDS.
[0057] The synchronizer SL may be formed in a known scheme, which
will be obviously understood without a further detailed
description, and a sleeve SLE included in the synchronizer SL may
be activated by an additional actuator controlled by a control
unit.
[0058] The differential device 20 receives a torque from the speed
reduction device 10, and distributes the received torque to the
left-side and right-side output shafts OS1 and OS2, while allowing
a rotation speed difference between the left and the right-side
drive wheels.
[0059] The differential device 20 includes a fifth planetary gear
set PG5 that includes seventh, eighth, and ninth rotation elements
N7, N8, and N9.
[0060] The fifth planetary gear set PG5 is a double pinion
planetary gear set, and includes a fifth sun gear S5, a fifth
planet carrier PC5 rotatably supporting a plurality of fifth pinion
gears P5 externally gear-meshed with the fifth sun gear S5, and a
fifth ring gear R5 internally gear-meshed with the plurality of
fifth pinion gears P3. The fifth sun gear S5 acts as a seventh
rotation element N7, the fifth planet carrier PC5 acts as an eighth
rotation element N8, and the fifth ring gear R5 acts as a ninth
rotation element N9.
[0061] The seventh rotation element N7 is fixedly connected to the
right-side output shaft OS2 and the eighth rotation element N8 is
fixedly connected to the left-side output shaft OS1. The ninth
rotation element N9 is fixedly connected to the driven gear PG of
the speed reduction device 10, as described above.
[0062] It may be understood that the driven gear PG may be
integrally formed at an external circumference of the fifth ring
gear R5, i.e., the ninth rotation element N9.
[0063] The torque vectoring device 30 adjusts a torque ratio
between the left-side and right-side drive wheels, and includes a
torque vectoring control motor TVCM and two compound planetary gear
sets CPG1 and CPG2.
[0064] The torque vectoring control motor TVCM, of which rotation
speed and rotating direction are controllable, is fixed to the
housing H, and an output gear OG is formed at a motor shaft MS of
the torque vectoring control motor TVCM.
[0065] The two compound planetary gear sets CPG1 and CPG2 are
symmetrically disposed side by side. Each of the two compound
planetary gear sets CPG1 and CPG2 is formed as two planetary gear
sets sharing a common planet carrier.
[0066] First compound planetary gear set CPG1 includes first and
second planetary gear sets PG1 and PG2 sharing a second rotation
element N2, i.e., a first common planet carrier.
[0067] The first planetary gear set PG1 is a single pinion
planetary gear set, and includes a first sun gear S1 and a first
common planet carrier CPC1 rotatably supporting a plurality of
first pinion gears P1 externally engaged with the first sun gear
S1, without including a ring gear. The first sun gear S1 acts a
first rotation element N1, and the first common planet carrier CPC1
acts as a second rotation element N2.
[0068] The second planetary gear set PG2 is a single pinion
planetary gear set, and includes the first common planet carrier
CPC1 rotatably supporting a plurality of second pinion gears P2 and
a second ring gear R2 internally engaged with the plurality of
second pinion gears P2, without including a sun gear. The first
common planet carrier CPC1 acts as the second rotation element N2,
and the second ring gear R2 acts a third rotation element N3.
[0069] Here, the first rotation element N1 is fixedly connected to
the housing H through a first connecting member CN1, and the second
rotation element N2 is fixedly connected to the eighth rotation
element N8 of the fifth planetary gear set PG5 through a second
connecting member CN2 to communicate torque with the differential
device 20.
[0070] Second compound planetary gear set CPG2 includes third and
fourth planetary gear sets PG3 and PG4 sharing a fourth rotation
element N4, i.e., a second common planet carrier PC2.
[0071] The third planetary gear set PG3 is a single pinion
planetary gear set, and includes a second common planet carrier
CPC2 rotatably supporting a plurality of third pinion gears P3 and
a third ring gear R3 internally engaged with the plurality of third
pinion gears P3, without including a sun gear. The second common
planet carrier CPC2 acts as a fourth rotation element N4, and the
third ring gear R3 acts a fifth rotation element N5.
[0072] The fourth planetary gear set PG4 is a single pinion
planetary gear set, and includes a fourth sun gear S4 and the
second common planet carrier CPC2 rotatably supporting a plurality
of fourth pinion gears P4 externally engaged with the fourth sun
gear S4, without including a rung gear. The fourth ring gear R4
acts a sixth rotation element N6, and the second common planet
carrier CPC2 acts as the fourth rotation element N4.
[0073] Here, the fourth rotation element N4 is fixedly connected to
the right-side output shaft OS2 through a third connecting member
CN3, and the fifth rotation element N5 is fixedly connected to the
third rotation element N3 through a fourth connecting member
CN4.
[0074] An input gear IG is fixedly connected to the sixth rotation
element N6 through a fifth connecting member CN5, and the input
gear IG is externally gear-meshed with the output gear OG of the
torque vectoring control motor TVCM.
[0075] Gear ratios of the first and second planetary gear sets PG1
and PG2 may be set symmetrically the same as gear ratios of the
third and fourth planetary gear sets PG3 and PG4. In more detail,
the gear ratio of the first planetary gear set PG1 may be set the
same as the gear ratio of the fourth planetary gear set PG4, and
the gear ratio of the second planetary gear set PG2 may be set the
same as the gear ratio of the third planetary gear set PG3.
[0076] Each of the five connecting members CN1 to CN5 may be a
rotation member which is fixedly connected to a rotation element of
the planetary gear sets PG1, PG2, PG3, PG4, and PG5, or may be a
rotation member that selectively interconnects a rotation element
to the transmission housing H, or may be a fixed member fixed to
the transmission housing H.
[0077] In the disclosure, when two or more members are described to
be "fixedly connected", where each of the members may be any of a
connecting member, left-side and right-side output shafts OS1 and
OS2, a rotation member, and a transmission housing, it means that
the fixedly connected members always rotate at a same speed.
[0078] Such a schemed torque vectoring device 30 realizes a torque
vectoring are configured to torques transmitted to the left-side
and right-side drive wheels as shown in FIG. 2, depending on
rotation speed and rotating direction of the torque vectoring
control motor TVCM.
[0079] FIG. 2A, FIG. 2B, and FIG. 2C are lever diagrams
illustrating torque vectoring operation of the torque vectoring
apparatus according to the exemplary embodiment of the present
invention.
[0080] Referring to FIG. 2A to FIG. 2C, a torque vectoring
apparatus according to an exemplary embodiment of the present
invention adjusts a torque distribution ratio between the left-side
and right-side output shafts OS1 and OS2 by controlling rotation
speed and direction of the torque vectoring control motor TVCM,
depending on a driving condition such as driving along a straight
line, or cornering to the left or right.
[0081] In FIG. 2A to FIG. 2C, the vertical axis represents rotation
speeds of the three rotation elements N7 to N9 of the fifth
planetary gear set PG5 in the differential device 20 and the six
rotation elements N1 to N6 of the first and second compound
planetary gear sets CPG1 and CPG2 in the torque vectoring device
30. The horizontal axis represents operational nodes of the torque
vectoring apparatus.
[0082] Operation of the torque vectoring apparatus depending on
driving conditions is hereinafter described in detail with
reference to FIG. 2.
[0083] The first rotation element N1 is fixed to the housing H, and
is therefore always stationary. The second rotation element N2 and
the eighth rotation element N8 are fixedly interconnected, and
therefore always rotate at a same speed. The third rotation element
N3 and the fifth rotation element N5 are fixedly interconnected,
and therefore always rotate at a same speed.
[0084] The sixth rotation element N6 is connected to the torque
vectoring control motor TVCM, and thereby the rotation speed and
direction of the sixth rotation element N6 are controlled by the
torque vectoring control motor TVCM. The ninth rotation element N9
receives a reduced rotation speed of the motor/generator MG through
the speed reduction device 10.
[0085] [Driving in a Straight Line]
[0086] Since the rotation element N1 is stationary, a speed line
between the first and second rotation elements N1 and N2 is formed
as shown in FIG. 2A, when the ninth rotation element N9 receives a
rotation speed from the motor/generator.
[0087] In the present situation, the torque vectoring control motor
TVCM is also stationary when driving in a straight line. Therefore,
a speed line between the sixth and fourth rotation elements N6 and
N4 is formed as shown in FIG. 2A, since the sixth rotation element
N6 always rotates at the same speed with the second rotation
element N2.
[0088] Since gear ratios of the first and second compound planetary
gear sets CPC1 and CPC2 are symmetrically formed, the third and
eighth rotation elements N3 and N8 are formed at a same height in
graph (same rotation speed) with the fifth and seventh rotation
elements N5 and N7.
[0089] Thus, in a straight line, a same torque is applied to the
left-side and right-side output shafts OS1 and OS2.
[0090] [Cornering to the Left]
[0091] As shown in FIG. 2B, cornering to the right of the vehicle
is realized while the torque vectoring control motor TVCM rotates
in a positive (+) direction thereof.
[0092] Since the torque vectoring control motor TVCM rotates in a
positive (+) direction thereof, the fourth rotation element N4 also
has a positive rotation speed, and therefore the speed line between
the sixth and fourth rotation elements N6 and N4 is formed as shown
in FIG. 2B.
[0093] Consequently, the speed of the fifth and seventh rotation
elements N5 and N7 is increased, since the fourth rotation element
N4 has a positive rotation speed.
[0094] Therefore, the speed of the fifth and seventh rotation
elements N5 and N7 becomes greater than the speed of the third and
eighth rotation elements N3 and N8, which means that a travel speed
of an external wheel becomes greater than a travel speed of an
internal wheel in a corner.
[0095] That is, a wheel connected to the second output shaft OS2
fixed to the fifth and seventh rotation elements N5 and N7 becomes
an external wheel, which means that a vehicle turns to the
left.
[0096] It is notable that, while turning to the left, the torque
vectoring control motor TVCM may be controlled to provide a torque
adjusted in the positive direction to enhance cornering agility of
a vehicle, which is advantageous in an understeer situation, or may
be control to provide a torque adjusted in the negative direction
to enhance stability of a vehicle, which is advantageous in an
oversteer situation.
[0097] That is, a torque vectoring apparatus according to an
exemplary embodiment of the present invention may achieve best
optimization of cornering agility and stability depending on
driving status.
[0098] [Cornering to the Right]
[0099] As shown in FIG. 2C, cornering to the left of the vehicle is
realized while the torque vectoring control motor TVCM rotates in a
negative (-) direction thereof.
[0100] Since the torque vectoring control motor TVCM rotates in a
negative (-) direction thereof, the fourth rotation element N4 also
has a negative rotation speed, and therefore the speed line between
the sixth and fourth rotation elements N6 and N4 is formed as shown
in FIG. 2C.
[0101] Consequently, the speed of the fifth and seventh rotation
elements N5 and N7 is decreased, since the fourth rotation element
N4 has a negative rotation speed.
[0102] Therefore, the speed of the fifth and seventh rotation
elements N5 and N7 becomes smaller than the speed of the third and
eighth rotation elements N3 and N8, which means that a travel speed
of an internal wheel becomes smaller than a travel speed of an
internal wheel in a corner.
[0103] That is, a wheel connected to the second output shaft OS2
fixed to the fifth and seventh rotation elements N5 and N7 becomes
an internal wheel, which means that a vehicle turns to the
right.
[0104] It is notable that, while turning to the right, the torque
vectoring control motor TVCM may be controlled to provide a torque
adjusted in the negative direction to enhance cornering agility of
a vehicle, which is advantageous in an understeer situation, or may
be control to provide a torque adjusted in the positive direction
to enhance stability of a vehicle, which is advantageous in an
oversteer situation.
[0105] That is, a torque vectoring apparatus according to an
exemplary embodiment of the present invention may achieve best
optimization of cornering agility and stability depending on
driving status.
[0106] When the rotation speed of the motor/generator MG exceed an
allowed limit by increasing speed of a vehicle, the synchronizer SL
of the speed reduction device 10 may be operated to disconnect
torque transmission from and to the motor/generator MG, and thereby
a vehicle may be driven without a load to the motor/generator
MG.
[0107] As described above, a torque vectoring apparatus according
to an exemplary embodiment of the present invention is applicable
to a high performance environmental vehicle provided with a
one-motor e-AWD (all wheel drive), and may achieve both cornering
performance and stability of a vehicle depending on driving
conditions.
[0108] Furthermore, when a vehicle speed becomes excessive to the
motor/generator MG, torque transmission from and to the
motor/generator MG may be disconnected, reducing undesired power
loss and improving fuel consumption.
[0109] Such a torque disconnection function may be applicable to a
hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle
(PHEV), and may be useful in disconnecting torque of a drive motor
in the case of running an internal combustion engine.
[0110] By employing a torque vectoring control motor TVCM in a
torque vectoring device, a torque vectoring function may be
optimally controlled, and power loss may be minimized, improving
fuel consumption characteristic.
[0111] By symmetrically forming two compound planetary gear sets in
the torque vectoring device, power loss of a torque vectoring
apparatus may be minimized and controllability of the torque
vectoring apparatus is maximized, since the torque vectoring
control motor TVCM may be merely stationary in a straight line.
[0112] For convenience in explanation and accurate definition in
the appended claims, the terms "upper", "lower", "inner", "outer",
"up", "down", "upper", "lower", "upwards", "downwards", "front",
"rear", "back", "inside", "outside", "inwardly", "outwardly",
"internal", "external", "inner", "outer", "forwards", and
"backwards" are used to describe features of the exemplary
embodiments with reference to the positions of such features as
displayed in the figures.
[0113] The foregoing descriptions of specific exemplary embodiments
of the present invention have been presented for purposes of
illustration and description. They are not intended to be
exhaustive or to limit the invention to the precise forms
disclosed, and obviously many modifications and variations are
possible in light of the above teachings. The exemplary embodiments
were chosen and described to explain certain principles of the
invention and their practical application, to enable others skilled
in the art to make and utilize various exemplary embodiments of the
present invention, as well as various alternatives and
modifications thereof. It is intended that the scope of the
invention be defined by the Claims appended hereto and their
equivalents.
* * * * *