U.S. patent application number 16/836557 was filed with the patent office on 2021-07-08 for torque vectoring apparatus.
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, Dong Hui CHEON, Junyoung HA, Baekyu KIM, Seok Joon KIM, Su Hyeon MAENG.
Application Number | 20210207698 16/836557 |
Document ID | / |
Family ID | 1000005666506 |
Filed Date | 2021-07-08 |
United States Patent
Application |
20210207698 |
Kind Code |
A1 |
AHN; Chulmin ; et
al. |
July 8, 2021 |
TORQUE VECTORING APPARATUS
Abstract
A torque vectoring apparatus receiving a vehicle driving torque
from a motor-generator may include a speed reduction device engaged
to the motor-generator and configured to reduce a rotation speed
received from the motor-generator, a differential device engaged to
the speed reduction device and configured to receive the
speed-reduced torque from the speed reduction device and to
differentially output torques to left and right output shafts, a
vectoring control motor outputting a control torque, and a torque
vectoring apparatus engaged to the vectoring control motor and
including two planetary gear sets and controlling a torque ratio
output to the left and right output shafts by the control torque of
the torque vectoring control motor, wherein the differential device
includes a differential case receiving a torque from the speed
reduction device, the differential case is mounted between the two
planetary gear sets rotatably on a connecting member connecting the
two planetary gear sets, and side gears in the differential case
are fixedly connected to the two planetary gear sets
respectively.
Inventors: |
AHN; Chulmin; (Anyang-Si,
KR) ; BYUN; SungGon; (Hwaseong-Si, KR) ; KIM;
Seok Joon; (Yongin-Si, KR) ; MAENG; Su Hyeon;
(Seoul, KR) ; CHEON; Dong Hui; (Hwaseong-Si,
KR) ; KIM; Baekyu; (Hwaseong-Si, KR) ; HA;
Junyoung; (Anyang-Si, 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: |
1000005666506 |
Appl. No.: |
16/836557 |
Filed: |
March 31, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F16H 2048/364 20130101;
B60W 30/18145 20130101; B60W 30/18009 20130101; F16H 2702/02
20130101; F16H 37/082 20130101; F16H 48/36 20130101; B60Y 2200/92
20130101; B60Y 2400/804 20130101; B60Y 2300/82 20130101; B60Y
2200/91 20130101 |
International
Class: |
F16H 48/36 20060101
F16H048/36; B60W 30/18 20060101 B60W030/18; F16H 37/08 20060101
F16H037/08 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 8, 2020 |
KR |
10-2020-0002687 |
Claims
1. A torque vectoring apparatus receiving a vehicle driving torque
from a motor-generator, the torque vectoring apparatus comprising:
a speed reduction device engaged to the motor-generator and
configured to reduce a rotation speed received from the
motor-generator; a differential device engaged to the speed
reduction device and configured to receive a speed-reduced torque
from the speed reduction device and to differentially output split
torques to a first output shaft and a second output shaft; a
vectoring control motor outputting a control torque; and a torque
vectoring apparatus engaged to the vectoring control motor and
including two planetary gear sets, wherein the torque vectoring
apparatus is configured to control a torque ratio of the split
torques output to the first output shaft and the second output
shaft by the control torque, wherein the differential device
includes a differential case receiving a torque from the speed
reduction device, wherein the differential case is mounted between
the two planetary gear sets rotatably on a connecting member
connecting the two planetary gear sets, and wherein side gears at a
first side and a second side in the differential case are fixedly
connected to the two planetary gear sets respectively.
2. The torque vectoring apparatus of claim 1, further including a
torque multiplication device including a first planetary gear set
having a first rotation element, a second rotation element, and a
third rotation element and being mounted on the first output shaft
between the torque vectoring apparatus and the torque vectoring
control motor, the second rotation element being engaged to the
torque vectoring control motor, and the third rotation element
being fixedly connected to a transmission housing, wherein the
torque multiplication device is configured to multiply a torque
received from the torque vectoring control motor and to output a
multiplied torque to the torque vectoring apparatus through the
first rotation element.
3. The torque vectoring apparatus of claim 1, wherein the first
planetary gear set is a single pinion planetary gear set including
a first sun gear, a first planet carrier, and a first ring gear as
the first rotation element, the second rotation element and the
third rotation element, respectively.
4. The torque vectoring apparatus of claim 2, wherein the two
planetary gear sets of the torque vectoring apparatus includes: a
second planetary gear set having a fourth rotation element, a fifth
rotation element, and a sixth rotation element, the fifth rotation
element being fixedly connected to a first side gear of the side
gears in the differential device and the first output shaft, and
the sixth rotation element being fixedly connected to the first
rotation element of the torque multiplication device; and a third
planetary gear set having a seventh rotation element, an eighth
rotation element, and a ninth rotation element, the seventh
rotation element being fixedly connected to the fourth rotation
element through the connecting member penetrating the differential
case, the eighth rotation element being fixedly connected to a
second side gear of the side gears in the differential device and
the second output shaft of the differential device, and the ninth
rotation element being fixedly connected to the transmission
housing.
5. The torque vectoring apparatus of claim 4, wherein the second
planetary gear set is a single pinion planetary gear set including
a second sun gear, a second planet carrier, and a second ring gear
as the fourth rotation element, the fifth rotation element, and the
sixth rotation element, respectively; and wherein the third
planetary gear set is a single pinion planetary gear set including
a third sun gear, a third planet carrier, and a third ring gear as
the seventh rotation element, the eighth rotation element, and the
ninth rotation element, respectively.
6. The torque vectoring apparatus of claim 4, wherein the
differential device includes: the differential case mounted between
the second planetary gear set and the third planetary gear set
rotatably on the connecting member fixedly connecting the fourth
rotation element and the seventh rotation element; a plurality of
differential gears rotatably mounted on internal surfaces of the
differential case; the first side gear and the second side gear
mounted at the first side and the second side, respectively, in the
differential case, rotatably mounted on the connecting member to be
engaged with the plurality of differential gears, and fixedly
connected to the fifth rotation element and the eighth rotation
element, respectively; and a final gear formed on an external
circumference of the differential case and connected to the speed
reduction device through a torque transmission member.
7. The torque vectoring apparatus of claim 6, wherein the torque
transmission member includes a chain or a belt.
8. The torque vectoring apparatus of claim 2, wherein the torque
vectoring control motor is connected to an output gear which is
engaged, through a torque transmission member, to an input gear
connected to the second rotation element.
9. The torque vectoring apparatus of claim 8, wherein the torque
transmission member includes a chain or a belt.
10. The torque vectoring apparatus of claim 1, wherein the torque
vectoring control motor is formed as a motor of which a rotation
speed and a rotation direction is configured to be controlled.
11. The torque vectoring apparatus of claim 6, wherein the speed
reduction device includes: a drive gear connected to a rotor of the
motor-generator through a hub; and an idle gear unit mounted
between the drive gear and the differential device to deliver a
speed-reduced torque of the motor-generator to the differential
device.
12. The torque vectoring apparatus of claim 11, wherein the idle
gear unit includes: an idle shaft positioned outside of the
differential device and in parallel with an axis of the first
output shaft and the second output shaft; an idle input gear
rotatably mounted on the idle shaft and gear-engaged with the drive
gear; and an idle output gear fixedly mounted on the idle shaft and
engaged to the final gear.
13. The torque vectoring apparatus of claim 12, wherein the idle
output gear is engaged to the final gear via a chain or a belt.
14. The torque vectoring apparatus of claim 11, wherein the idle
gear unit further includes: a synchronizer mounted between the idle
input gear and the idle shaft and configure to selectively
synchronize the idle input gear and the idle shaft.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] The present application claims priority to Korean Patent
Application No. 10-2020-0002687 filed on Jan. 8, 2020, 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 mounted 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 included 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 receiving a vehicle driving
torque from a motor-generator, including a speed reduction device
engaged to the motor-generator and configured to reduce a rotation
speed received from the motor-generator, a differential device
engaged to the speed reduction device and configured to receive the
speed-reduced torque from the speed reduction device and to
differentially output split torques to left-side and right-side
output shafts, a vectoring control motor outputting a control
torque, and a torque vectoring apparatus engaged to the vectoring
control motor and including two planetary gear sets and controlling
a torque ratio of the split torques output to the left-side and
right-side output shafts by a torque received from the torque
vectoring control motor. The differential device may include a
differential case receiving a torque from the speed reduction
device. The differential case may be mounted between the two
planetary gear sets rotatably on a connecting member connecting the
two planetary gear sets. Side gears at both sides in the
differential case may be fixedly connected to the two planetary
gear sets respectively.
[0014] The exemplary torque vectoring apparatus may further include
a torque multiplication device including a first planetary gear set
having first, second, and third rotation elements and being mounted
on a first one of the left-side and right-side output shafts
between the torque vectoring apparatus and the torque vectoring
control motor, the second rotation element being engaged to the
torque vectoring control motor, the third rotation element being
fixedly connected to a transmission housing. The torque
multiplication device may be configured to multiply a torque
received from the torque vectoring control motor and to output the
multiplied torque to the torque vectoring apparatus through the
first rotation element.
[0015] The first planetary gear set may be a single pinion
planetary gear set including a first sun gear, a first planet
carrier, and a first ring gear as the first, second, and third
rotation elements.
[0016] The torque vectoring apparatus may include second and third
planetary gear sets. The second planetary gear set may have fourth,
fifth, and sixth rotation elements, the fifth rotation element
being fixedly connected to a first side gear of the differential
device and the first output shaft, the sixth rotation element being
fixedly connected to the first rotation element of the torque
multiplication device, and
[0017] The third planetary gear set have seventh, eighth, and ninth
rotation elements, the seventh rotation element being fixedly
connected to the fourth rotation element through the connecting
member penetrating the differential case, the eighth rotation
element being fixedly connected to a second side gear and a second
one of the left-side and right-side output shafts of the
differential device, the ninth rotation element being fixedly
connected to the transmission housing.
[0018] The second planetary gear set may be a single pinion
planetary gear set, and may include a second sun gear, a second
planet carrier, and a second ring gear as the fourth, fifth, and
sixth rotation elements. The third planetary gear set may be a
single pinion planetary gear set, and may include a third sun gear,
a third planet carrier, and a third ring gear as the seventh,
eighth, and ninth rotation elements.
[0019] The differential device may include the differential case
mounted between the second planetary gear set and the third
planetary gear set rotatably on the connecting member fixedly
connecting the fourth rotation element and the seventh rotation
element, a plurality of differential gears rotatably mounted on
internal surfaces of the differential case, the first side gear and
the second side gear mounted at both sides in the differential
case, rotatably mounted on the connecting member to be engaged with
the plurality of differential gears, and fixedly connected to the
fifth rotation element and the eighth rotation element,
respectively, and a final gear formed on an external circumference
of the differential case and connected to the speed reduction
device through a torque transmission member.
[0020] The torque vectoring control motor may be connected to an
output gear which is connected, through a torque transmission
member, to an input gear connected to the second rotation
element.
[0021] The torque vectoring control motor may be formed as a motor
of which a rotation speed and a rotation direction may be
controlled.
[0022] The speed reduction device may include a drive gear
connected to a rotor of the motor-generator through a hub, and an
idle gear unit mounted between the drive gear and the differential
device to deliver a speed-reduced torque of the motor-generator to
the differential device.
[0023] The idle gear unit may include an idle shaft mounted
external to the differential device and in parallel with an axis of
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 mounted on the idle
shaft and engaged to the final gear.
[0024] The idle gear unit may further include a synchronizer
mounted between the idle input gear and the idle shaft and
configure to selectively synchronize the idle input gear and the
idle shaft.
[0025] An exemplary torque vectoring apparatus 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.
[0026] 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.
[0027] 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.
[0028] By symmetrically forming two planetary gear sets in the
torque vectoring apparatus, 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.
[0029] Fuel consumption loss in driving along a straight line may
be minimized, since one ring gear of the two planetary gear sets of
the torque vectoring apparatus always acts as a fixed element, and
the differential is mounted between the two planetary gear sets.
Since a control torque of the torque vectoring control motor TVCM
is multiplied by use of a planetary gear set, power loss in driving
the torque vectoring control motor TVCM is minimized, improving
fuel consumption characteristic.
[0030] Other effects which may be obtained or are predicted by an
exemplary embodiment 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
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 present invention. The specific design features
of the present invention as included 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 portions 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 present
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 present
invention(s) to those exemplary embodiments. On the other hand, the
present 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 present
invention as defined by the appended claims.
[0037] Hereinafter, an exemplary embodiment 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, a torque vectoring control
motor TVCM, a torque vectoring apparatus 30, and a torque
multiplication device 40. The differential device 20, the torque
vectoring control motor TVCM, the torque vectoring apparatus 30,
and the torque multiplication device 40 are mounted 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 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 apparatus 30 adjusts a torque ratio
split to the left-side and right-side drive wheels by use of a
torque of the torque vectoring control motor TVCM delivered from
the torque multiplication device 40 according to driving conditions
such as cornering or driving in a straight line, and thereby
improves driving performance such as a cornering 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-side driveshafts.
[0045] The motor-generator MG includes a stator ST fixed to a
transmission 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 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 in a speed at the idle gear unit IDGU. The
speed-reduced torque is output from the speed reduction device 10
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 idle gear unit IDGU reduces the rotation speed through
two idle gears provided on an idle shaft IDS.
[0050] That is, the idle shaft IDS is mounted radially external to
the differential device 20, and mounted in parallel with the
left-side and right-side output shafts OS1 and OS2.
[0051] Two idle gears of an idle input gear IDG1 and an idle output
gear IDG2 are formed on the idle shaft IDS.
[0052] The idle input gear IDG1 is rotatably mounted on the idle
shaft IDS, and is externally gear-meshed with the drive gear
DG.
[0053] The idle output gear IDG2 is fixedly mounted on the idle
shaft IDS, and is connected to the differential device 20.
[0054] The idle gear unit IDGU further includes a synchronizer SL
mounted on the idle shaft IDS, to selectively synchronize the idle
input gear IDG1 to the idle shaft IDS, to connect or disconnect
torque transmission between the motor-generator MG and the
differential device 20.
[0055] The synchronizer SL is mounted between the idle input gear
IDG1 and the idle shaft IDS, and selectively synchronizes the idle
input gear IDG1 to the idle shaft IDS.
[0056] 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.
[0057] The torque vectoring control motor TVCM is fixed to the
transmission housing H, and is formed as a motor of which a
rotation speed and a rotation direction may be controlled. The
torque vectoring control motor TVCM is provided with an output gear
OG on a motor shaft to output a torque.
[0058] The torque vectoring apparatus 30 adjusts a torque ratio
between the left-side and right-side drive wheels by use of a
torque received from the torque vectoring control motor TVCM, and
includes second and third planetary gear sets PG2 and PG3.
[0059] The second planetary gear set and the third planetary gear
set PG2 and PG3 are mounted apart from each other, interposing the
differential device 20.
[0060] The second planetary gear set PG2 is a single pinion
planetary gear set having fourth, fifth, and sixth rotation
elements N4, N5, and N6, and includes the fourth rotation element
N4 of a second sun gear S2, the fifth rotation element N5 of a
second planet carrier PC2 rotatably supporting a plurality of
second pinion gears P2 externally gear-meshed with the second sun
gear S2, and the sixth rotation element N6 of a second ring gear R2
internally gear-meshed with the plurality of second pinion gears
P2.
[0061] The third planetary gear set PG3 is a single pinion
planetary gear set having seventh, eighth, and ninth rotation
elements N7, N8, and N9, and includes the seventh rotation element
N7 of a third sun gear S3, the eighth rotation element N8 of a
third planet carrier PC3 rotatably supporting a plurality of third
pinion gears P3 externally gear-meshed with the third sun gear S3,
and the ninth rotation element N9 of a third ring gear R3
internally gear-meshed with the plurality of third pinion gears
P3.
[0062] The fourth rotation element N4 is fixedly connected to the
seventh rotation element N7 through a fourth connecting member CN4.
The fifth rotation element N5 is fixedly connected to the
right-side output shaft OS2 through a third connecting member CN3.
The sixth rotation element N6 is connected to the torque
multiplication device 40 through a first connecting member CN1,
receiving the torque of the torque vectoring control motor
TVCM.
[0063] The eighth rotation element N8 is fixedly connected to the
left-side output shaft OS1 through a fifth connecting member CN5.
The ninth rotation element N9 is fixedly connected to the
transmission housing H through a sixth connecting member CN6,
always acting as a fixed element.
[0064] The fourth connecting member CN4 fixedly connecting the
fourth rotation element N4 and the seventh rotation element N7 may
be mounted on an axis of the left-side and right-side output shafts
OS1 and OS2. The second planetary gear set and the third planetary
gear set PG2 and PG3 may have same gear ratios.
[0065] 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.
[0066] The differential device 20 includes a differential case DC
receiving a torque from the speed reduction device 10 through a
final gear FG, and a differential DIFF mounted between the second
planetary gear set and the third planetary gear set PG2 and PG3 of
the torque vectoring apparatus 30.
[0067] Since the differential case DC is mounted between the second
planetary gear set and the third planetary gear set PG2 and PG3,
the differential DIFF is rotatably mounted on the third connecting
member CN4 that fixedly connects the fourth rotation element N4 and
the seventh rotation element N7.
[0068] A plurality of differential gears DFG are rotatably mounted
in differential case DC. First and second side gears SG1 and SG2
are rotatably mounted on the fourth connecting member CN4 at both
sides of the differential case DC, and are engaged with the
plurality of differential gears DFG
[0069] The first side gear SG1 is fixedly connected to the fifth
rotation element N5 of the torque vectoring apparatus 30 through
the third connecting member CN3, and connected to the right-side
output shaft OS2. The second side gear SG2 is fixedly connected to
the eighth rotation element N8 of the torque vectoring apparatus 30
through the fifth connecting member CN5, and connected to the
left-side output shaft OS1.
[0070] The final gear FG is formed on an external circumference of
the differential case DC, and connected to the speed reduction
device 10 through a torque transmission member TC.
[0071] The differential DIFF is rotatably mounted on the fourth
connecting member CN4 fixedly connecting the fourth rotation
element N4 and the seventh rotation element N7 of the second
planetary gear set and the third planetary gear set PG2 and PG3.
The first and second side gears SG1 and SG2 within the differential
case DC absorb a rotation speed difference between the left-side
and right-side drive wheels. Thus, the differential DIFF may
transmit a torque to both output shafts OS1 and OS2 through the
fifth and eighth rotation elements N5 and N8 of the second
planetary gear set and the third planetary gear set PG2 and
PG3.
[0072] The torque transmission member TC may be formed as a chain
or a belt such as a metal belt or a pulley belt.
[0073] The torque multiplication device 40 may include a first
planetary gear set PG1 mounted on an axis of the right-side output
shaft OS2 between the torque vectoring apparatus 30 and the torque
vectoring control motor TVCM.
[0074] The first planetary gear set PG1 is a single pinion
planetary gear set having first, second, and third rotation
elements N1, N2, and N3, and includes the first rotation element N1
of a first sun gear S1, the second rotation element N2 of a first
planet carrier PC1 rotatably supporting a plurality of first pinion
gears P1 externally gear-meshed with the first sun gear S1, and the
third rotation element N3 of a first ring gear R1 internally
gear-meshed with the plurality of first pinion gears P1.
[0075] The first rotation element N1 is fixedly connected to the
sixth rotation element N6 of the torque vectoring apparatus 30
through first connecting member CN1. The second rotation element N2
is connected to the torque vectoring control motor TVCM. The third
rotation element N3 is fixedly connected to the transmission
housing through the second connecting member CN2, always acting as
a fixed element.
[0076] The torque multiplication device 40 multiplies a torque
received from the torque vectoring control motor TVCM through the
second rotation element N2, and outputs the multiplied torque to
the sixth rotation element N6 of the torque vectoring apparatus 30
through the first rotation element N1.
[0077] The second rotation element N2 fixedly connected to an input
gear IG The input gear IG is connected to the output gear OG on the
motor shaft of the torque vectoring control motor TVCM through the
torque transmission member TC.
[0078] The torque transmission member TC may be formed as a chain
or a belt such as a metal belt or a pulley belt.
[0079] Each of the six connecting members CN1 to CN6 may be a
rotation member which is fixedly connected to a rotation element of
the planetary gear sets PG1, PG2, and PG3, 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.
[0080] In an exemplary embodiment of the present invention, 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.
[0081] Such a schemed torque vectoring apparatus 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 rotation direction of the torque vectoring
control motor TVCM.
[0082] 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.
[0083] 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.
[0084] In FIG. 2A to FIG. 2C, the vertical axis represents rotation
speeds of the six rotation elements N4 to N9 of the second and
third planetary gear set PG2 and PG3 in the differential device 20.
The horizontal axis represents operational nodes of the torque
vectoring apparatus.
[0085] Operation of the torque vectoring apparatus depending on
driving conditions is hereinafter described in detail with
reference to FIG. 2.
[0086] The fourth rotation element N4 is fixedly connected to the
seventh rotation element N7. The fifth rotation element N5 is
fixedly connected to the right-side output shaft OS2. The sixth
rotation element N6 is fixedly connected to the first rotation
element N1, and thereby the rotation speed and direction of the
sixth rotation element N6 are controlled by the torque vectoring
control motor TVCM.
[0087] The eighth rotation element N8 is fixedly connected to the
left-side output shaft OS1. The ninth rotation element N9 is fixed
to the transmission housing H. The fifth and eighth rotation
elements N5 and N8 are fixedly connected to the first and second
side gears SG1 and SG2 of the differential DIFF and receive reduced
speeds of the motor-generator MG through the speed reduction device
10.
[0088] [Driving in a Straight Line]
[0089] As shown in FIG. 2A, driving in a straight line of the
vehicle is realized while the torque vectoring control motor TVCM
is stationary, i.e., rotating in a zero speed.
[0090] Since the rotation element N9 is stationary, a speed line
between the ninth and seventh rotation elements N9 and N7 is formed
as shown in FIG. 2A, when the seventh rotation element N7 receives
a rotation speed from the motor-generator MG.
[0091] 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 is also stationary.
[0092] Since gear ratios of the second and third compound planetary
gear sets PG2 and PG3 are symmetrically formed, the eighth and
fifth rotation elements N8 and N5 are formed at a same height (a
same rotation speed) in the graph.
[0093] Thus, in a straight line, a same torque is applied to the
left-side and right-side output shafts OS1 and OS2.
[0094] [Cornering to the Left]
[0095] 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.
[0096] Since the torque vectoring control motor TVCM rotates in a
positive (+) direction thereof, the first and sixth rotation
element N1 and N6 also have 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.
[0097] Consequently, the speed of the fifth rotation element N5 is
increased, since the sixth rotation element N6 has a positive
rotation speed.
[0098] Therefore, the speed of the fifth rotation element N5
becomes greater than the speed of the eighth rotation element N8,
which means that a travel speed of the right-side drive wheel is
greater than a travel speed of the left-side drive wheel.
[0099] It may be understood that a travel speed of an external
wheel of a vehicle in a corner becomes greater than a travel speed
of an internal wheel of a vehicle. Therefore, a wheel connected to
the right-side output shaft OS2 fixed to the fifth rotation
elements N5 becomes an external wheel of a corner, which means that
a vehicle turns to the left.
[0100] 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.
[0101] 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.
[0102] [Cornering to the Right]
[0103] 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.
[0104] Since the torque vectoring control motor TVCM rotates in a
negative (-) direction thereof, the first and sixth rotation
element N1 and N6 also have 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. 2B.
[0105] Consequently, the speed of the fifth rotation element N5 is
decreased, since the sixth rotation element N6 has a negative
rotation speed.
[0106] Therefore, the speed of the fifth rotation element N5
becomes smaller than the speed of the eighth rotation element N8,
which means that a travel speed of the right-side drive wheel is
smaller than a travel speed of the left-side drive wheel.
[0107] It may be understood that a travel speed of an external
wheel of a vehicle in a corner becomes greater than a travel speed
of an internal wheel of a vehicle. Therefore, a wheel connected to
the right-side output shaft OS2 fixed to the fifth rotation
elements N5 becomes an internal wheel of a corner, which means that
a vehicle turns to the right.
[0108] 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.
[0109] 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.
[0110] 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.
[0111] 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.
[0112] 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.
[0113] 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.
[0114] Fuel consumption loss in driving along a straight line may
be minimized, since one ring gear R3 of the two planetary gear sets
PG2 and PG3 of the torque vectoring apparatus 30 always acts as a
fixed element, and the differential DIFF is mounted between the two
planetary gear sets PG2 and PG3.
[0115] Since a control torque of the torque vectoring control motor
TVCM is multiplied by use of a planetary gear set PG1, power loss
in driving the torque vectoring control motor TVCM is minimized,
improving fuel consumption characteristic.
[0116] By symmetrically forming the second planetary gear set and
the third planetary gear set PG2 and PG3 in the torque vectoring
apparatus, 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.
[0117] While the present invention has been described in connection
with what is presently considered to be practical exemplary
embodiments of the present invention, it is to be understood that
the present invention is not limited to the included exemplary
embodiments. On the other hand, it is directed to cover various
modifications and equivalent claims as well as various alternatives
and modifications thereof. It is intended that the scope of the
present invention be defined by the Claims appended hereto and
their equivalents."
[0118] For convenience in explanation and accurate definition in
the appended claims, the terms "upper", "lower", "inner", "outer",
"up", "down", "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. It will
be further understood that the term "connect" or its derivatives
refer both to direct and indirect connection.
[0119] Furthermore, the term of "fixedly connected" signifies that
fixedly connected members always rotate at a same speed.
Furthermore, the term of "selectively connectable" signifies
"selectively connectable members rotate separately when the
selectively connectable members are not engaged to each other,
rotate at a same speed when the selectively connectable members are
engaged to each other, and are stationary when at least one of the
selectively connectable members is a stationary member and
remaining selectively connectable members are engaged to the
stationary member".
[0120] 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 present 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
present 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 present invention be defined by the Claims appended
hereto and their equivalents.
* * * * *