U.S. patent application number 15/067752 was filed with the patent office on 2016-07-07 for ball type cvt with powersplit paths.
The applicant listed for this patent is Dana Limited. Invention is credited to Matthias W.J. BYLTIAUW, Mark R.J. VERSTEYHE.
Application Number | 20160195177 15/067752 |
Document ID | / |
Family ID | 50237654 |
Filed Date | 2016-07-07 |
United States Patent
Application |
20160195177 |
Kind Code |
A1 |
VERSTEYHE; Mark R.J. ; et
al. |
July 7, 2016 |
BALL TYPE CVT WITH POWERSPLIT PATHS
Abstract
A variable transmission comprises an input shaft; three
planetary gear sets; a Ravigneaux gear set; a variator comprising,
a first ring assembly, a second ring assembly, a carrier assembly;
various arrangements of brakes and clutches; and the output shaft.
The variable transmissions comprise a continuously variable mode,
an infinitely variable mode, or a combination thereof and can
provide an input-coupled powersplit solution function. At least one
configuration of the variable transmission comprises a direct drive
mode.
Inventors: |
VERSTEYHE; Mark R.J.;
(Oostkamp, BE) ; BYLTIAUW; Matthias W.J.;
(Hooglede, BE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Dana Limited |
Maumee |
OH |
US |
|
|
Family ID: |
50237654 |
Appl. No.: |
15/067752 |
Filed: |
March 11, 2016 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
14426139 |
Mar 4, 2015 |
|
|
|
PCT/US2013/058615 |
Sep 6, 2013 |
|
|
|
15067752 |
|
|
|
|
61789645 |
Mar 15, 2013 |
|
|
|
61698012 |
Sep 7, 2012 |
|
|
|
Current U.S.
Class: |
475/189 |
Current CPC
Class: |
F16H 2037/0873 20130101;
F16H 2037/0893 20130101; F16H 37/10 20130101; F16H 37/022 20130101;
F16H 37/086 20130101; F16H 2037/107 20130101; F16H 15/503 20130101;
F16H 15/28 20130101; F16H 37/082 20130101; F16H 2037/103
20130101 |
International
Class: |
F16H 37/08 20060101
F16H037/08; F16H 37/10 20060101 F16H037/10; F16H 37/02 20060101
F16H037/02 |
Claims
1. A variable transmission comprising: an input shaft; a variator
comprising a first ring assembly and a second ring assembly; a
first planetary gear set, a second planetary gear set and a third
planetary gear set; a Ravigneaux gear set; a first clutch and a
second clutch; and a first brake, a second brake, and a third
brake; wherein the input shaft is drivingly engaged with a first
sun gear of the first planetary gear set having the second brake
coupled to a first ring gear of this first planetary gear set, the
input shaft is drivingly engaged with a second carrier of the
second planetary gear set, a second sun gear of the second
planetary gear set is coupled to the first ring assembly of the
variator, the second ring assembly of the variator is drivingly
engaged with a third sun gear of the third planetary gear set
through the second clutch, the third sun gear and a third carrier
of the third planetary are coupled by a second clutch, the third
brake is coupled to a third ring gear of the third planetary, the
third carrier of the third planetary gear set is drivingly engaged
with a second ring gear of the second planetary gear set, the
second ring gear of the second planetary gear set is drivingly
engaged with a fourth sun gear of the Ravigneaux gear set which is
coupled to the first brake by a fifth sun of the Ravigneaux gear
set, the first clutch engages the fourth sun of the Ravigneaux gear
set to a fourth carrier of the Ravigneaux gear set, a fourth ring
of the Ravigneaux gear set is coupled to an output of the variable
transmission, and the fourth carrier of the Ravigneaux gear set is
coupled to a first carrier of the first planetary gear set.
2. The variable transmission of claim 1, wherein the third brake is
configured to release the third ring of the third planetary gear
set.
3. The variable transmission of claim 1, comprising a first
continuously variable mode (CVM1), a second continuously variable
mode (CVM2), a continuously variable mode (CVM3), and an infinitely
variable mode.
4. The variable transmission of claim 3 wherein the fourth sun of
the Ravigneaux gear set is engaged to the third carrier of the
third planetary gear set in each of the first continuously variable
mode (CVM1), the second continuously variable mode (CVM2), the
continuously variable mode (CVM3), and the infinitely variable
mode.
5. The variable transmission of claim 3, wherein in the first
continuously variable mode (CVM1), or the second continuously
variable mode (CVM2), the third brake is engaged.
6. The variable transmission of claim 3, wherein in the infinitely
variable mode the third brake is engaged.
7. The variable transmission of claim 3, wherein in the third
continuously variable mode (CVM3), the third brake is disengaged,
the first clutch is engaged, and the second clutch is engaged.
8. The variable transmission of claim 6, wherein when the third sun
and third carrier of the third planetary are coupled, the third
planetary gear set to turn at a 1:1 ratio.
9. The variable transmission of claim 1, wherein the variator
continuously changes its torque ratios in the first continuously
variable mode (CVM1), the second continuously variable mode (CVM2),
the continuously variable mode (CVM3), and the infinitely variable
mode to optimize power consumption.
10. The variable transmission of claim 1, comprising a traction
fluid.
11. A vehicle driveline comprising the variable transmission of
claim 1 disposed between an engine and a vehicle output.
12. The vehicle driveline of claim 11, wherein the vehicle output
comprises a differential and a drive axle.
13. The vehicle driveline of claim 11, comprising a torsional
dampener disposed between the engine and the variable
transmission.
14. The vehicle driveline of claim 11, wherein the torsional
dampener comprises at least one torsional spring.
15. A method comprising switching between an infinitely variable
mode and a continuously variable mode using the variable
transmission of claim 1.
16. A method comprising switching between an infinitely variable
mode and two continuously variable modes using the variable
transmission of claim 1.
17. A method comprising switching between an infinitely variable
mode and three continuously variable modes using the variable
transmission 1.
18. A vehicle comprising the variable transmission of claim 1
disposed between an engine and a vehicle output.
19.-29. (canceled)
Description
CROSS-REFERENCE
[0001] This application is a continuation of U.S. application Ser.
No. 14/426,139, filed on Mar. 4, 2015, which is the National Phase
Entry of International Application No. PCT/US2013/058615, filed on
Sep. 6, 2013, which claims the benefit of U.S. Provisional Patent
Application No. 61/698,012, filed Sep. 7, 2012 and U.S. Provisional
Patent Application No. 61/789,645, filed Mar. 15, 2013, all of
which are incorporated herein by reference in their entireties.
BACKGROUND OF THE INVENTION
[0002] Automatic and manual transmissions are commonly used on
automobile vehicles. Those transmissions are becoming more and more
complicated since the engine speed has to be more precisely
controlled to limit the fuel consumption and the emissions of cars.
This finer control of the engine speed in usual transmissions can
only be done by adding more discrete step ratio gears and
increasing the overall complexity and cost. Consequently, 6-speed
manual transmissions then become more frequently used as are 8 or 9
speed automatic transmissions.
SUMMARY OF THE INVENTION
[0003] Provided herein is a variable transmission comprising: an
input shaft; three planetary gear sets; a Ravigneaux gear set; a
variator comprising, a first ring assembly, a second ring assembly,
a carrier assembly; various arrangements of brakes and clutches;
and the output shaft.
[0004] In some embodiments, the variable transmission comprises a
continuously variable mode, an infinitely variable mode or a
combination thereof.
[0005] In some embodiments the variable transmission can provide an
input-coupled powersplit solution function.
[0006] In some embodiments, the transition between continuously
variable transmission mode and infinitely variable transmission
mode is accomplished by releasing or engaging one or more brakes,
and/or alternatively releasing or engaging one or more clutches
simultaneously.
[0007] In some embodiments, the variator is able to continuously
change its ratios in both the continuously variable mode and
infinitely variable mode to provide the best ratio achievable for
the engine to optimize power consumption.
[0008] Provided herein is a variable transmission comprising: an
input shaft; a first planetary gear set, a second planetary gear
set and a third planetary gear set; a variator comprising a first
ring assembly, a second ring assembly; a first clutch, a second
clutch and a third clutch; and a first brake comprising a first
brake member, wherein said input shaft is drivingly engaged with
the first ring assembly of the variator, and mechanically
coupleable to a first planetary sun of the first planetary gear set
using the second clutch; wherein said input shaft is also drivingly
engaged with the third sun of the third planetary gear set; wherein
the second ring assembly is drivingly engaged with a ring of the
third planetary gear set; wherein a first carrier of the first
planetary gear set and a second carrier of the second planetary
gear set are coupled together, wherein a third carrier of the third
planetary gear set is mechanically coupleable to the first carrier
of the first planetary and the second carrier of the second
planetary through the third clutch; wherein the first brake member
is coupled to the ring of the second planetary gear set; and
wherein the first ring of the first planetary gear set is
mechanically coupled to an output shaft of the variable
transmission; wherein the third carrier is mechanically coupled to
the second sun of the second planetary gear set; wherein the first
sun of the first planetary gear set might be coupled to the first
ring of the first planetary gear set with the first clutch.
[0009] In some embodiments, the variable transmission comprises two
continuously variable modes, an infinitely variable mode and a
direct drive mode. In some embodiments, the continuously variable
modes of claim 2 comprise a low speed (CVM1) and a high speed
(CVM2). In some embodiments, either or both of the continuously
variable modes are enabled by blocking rotation of a variator
carrier of the variator.
[0010] In some embodiments, power from the input shaft passes
through the variator and simultaneously passes to a vehicle output.
In some embodiments, a slipping clutch is not required between the
input shaft and the variable transmission. In some embodiments, a
torque converter is not required between the input shaft and the
variable transmission
[0011] In some embodiments, engaging the second clutch and the
first brake results in an infinitely variable mode. In some
embodiments, reverse and low positive speeds can be obtained when
the input shaft is directly engaged to the first sun of the first
planetary gear set by engaging a second clutch.
[0012] In some embodiments, engaging the first clutch and the first
brake at the second planetary gear set reduces speed of the second
ring assembly and allows the first planetary gear set to turn at a
1:1 ratio, thereby engaging a first continuously variable mode
(CVM1).
[0013] In some embodiments, engaging the first clutch and the third
clutch directly drives the variator second ring assembly linked to
the first carrier through a 1:1 output ratio from the variator
which drives output of the first planetary gear set, thereby
engaging a second continuously variable mode (CVM2).
[0014] In some embodiments, engaging the second clutch and the
first brake engage an infinitely variable mode that allows
positive, negative speeds and powered neutral.
[0015] In some embodiments, engaging the first clutch and the
second clutch bypasses the variator and allows output of the first
planetary gear set to turn at a 1:1 ratio with the input shaft,
directly engaging a vehicle output, thus engaging a direct-drive
mode, In some embodiments, the direct-drive mode is more efficient
than either of the two continuously variable modes. In some
embodiments, the native efficiency of the variable transmission is
increased by using the variator in a power-splitting continuously
variable mode.
[0016] Provided herein is a variable transmission comprising: an
input shaft; a variator comprising a first ring assembly, a second
ring assembly; a first planetary gear set, a second planetary gear
set and a third planetary gear set; a Ravigneaux gear set; a first
clutch; a first brake and a second brake, wherein the input shaft
is drivingly engaged with a first sun of the first planetary gear
set having the second brake coupled to the ring of this first
planetary; wherein the input shaft is drivingly engaged with a
second carrier of the second planetary gear set; wherein a second
sun of the second planetary gear set is coupled to the first ring
assembly of the variator, wherein the second ring assembly is
drivingly engaged with a third sun of the third planetary gear,
wherein the third ring of the third planetary gear set is fixed to
ground , wherein a third carrier of the third planetary gear set is
drivingly engaged to a second ring of the second planetary gear
set; wherein a second ring of the second planetary gear set is
drivingly engaged with the first sun of the Ravigneaux gear set,
the Ravigneaux gear set being mechanically coupled to the first
brake via its second sun; and wherein a carrier of the Ravineaux
gear set is engaged with a first carrier of the first planetary
gear set, and wherein the ring of the Ravigneaux gear set is
engaged with a output of the variable transmission; wherein a first
clutch engages the first sun of the Ravigneaux gear set to the
carrier of the Ravigneaux gear set.
[0017] In some embodiments, the first brake holds the second sun of
the Ravigneaux gear set.
[0018] In some embodiments, the variable transmission comprises a
first continuously variable mode, a second continuously variable
mode, and an infinitely variable mode. In some embodiments, the
first sun of the Ravigneaux gear set is engaged to the third
carrier of the third planetary gear set in all of the first
continuously variable mode, the second continuously variable mode,
and the infinitely variable mode. In some embodiments, the second
brake is engaged to hold the first ring of the first planetary gear
set, thereby engaging the infinitely variable mode. In some
embodiments, the speed of second ring of the Ravigneaux is
reduced.
[0019] In some embodiments, when the first brake is engaged the
second sun is held which results in a first continuously variable
mode (CVM1) of operation.
[0020] In some embodiments, when the first clutch is engaged, the
Ravigneaux gear set is engaged which results in a second
continuously variable mode (CVM2) of operation. In some
embodiments, in the second continuously variable mode (CVM2) of
operation the entire Ravigneaux gear set turns at the same speed,
and achieves an efficient 1:1 ratio.
[0021] Provided herein is a variable transmission comprising: an
input shaft; a variator comprising a first ring assembly, a second
ring assembly; a first planetary gear set; a second planetary gear
set; a third planetary gear set; a Ravigneaux gear set; a first
clutch and a second clutch; and a first brake, a second brake, and
a third brake, wherein the input shaft is drivingly engaged with a
first sun of the first planetary gear set having the second brake
coupled to the ring of this first planetary; wherein the input
shaft is drivingly engaged with a second carrier of the second
planetary gear set; wherein a second sun of the second planetary
gear set is coupled to the first ring assembly of the variator,
wherein the second ring assembly is drivingly engaged with a third
sun of the third planetary gear set, wherein the third sun and the
third carrier of the third planetary gear set are coupled by a
second clutch; wherein the third brake is coupled to the ring of
the third planetary; wherein the carrier of the third planetary
gear set is drivingly engaged with a second ring of the second
planetary gear set; wherein the second ring of the second planetary
gear set is drivingly engaged with a first sun of the Ravigneaux
gear set, and wherein the Ravigneaux gear set is coupled to the
first brake by its second sun and wherein a carrier of the
Ravineaux gear set is engaged with a first carrier of the first
planetary gear set; wherein a first clutch engages the first sun of
the Ravigneaux gear set to the carrier of the Ravigneaux gear
set.
[0022] In some embodiments, the third brake is configured to
release a third ring of the third planetary gear set.
[0023] In some embodiments, the variable transmission comprises a
first continuously variable mode (CVM1), a second continuously
variable mode CVM2), a continuously variable mode (CVM3), and an
infinitely variable mode.
[0024] In some embodiments, the first sun of the Ravigneaux gear
set is engaged to the carrier of the third planetary gear set.
[0025] In some embodiments, in the first continuously variable mode
(CVM1), or the second continuously variable mode (CVM2), the third
brake is engaged.
[0026] In some embodiments, in the infinitely variable mode the
third brake is engaged.
[0027] In some embodiments, in the third continuously variable mode
(CVM3), the third brake is disengaged, the first clutch is engaged,
and the second clutch is engaged.
[0028] In some embodiments, when the third sun and third carrier of
the third planetary are coupled by engaging the second clutch, the
third planetary gear set to turn at a 1:1 ratio.
[0029] In some embodiments, the variator continuously changes its
torque ratios in the first continuously variable mode (CVM1), the
second continuously variable mode CVM2), the continuously variable
mode (CVM3), and the infinitely variable mode to optimize power
consumption.
[0030] In some embodiments, the variable transmission comprises a
traction fluid.
[0031] Provided herein is a vehicle driveline comprising a variable
transmission described herein or that would be obvious to one of
skill in the art upon reading the disclosure herein disposed
between an engine and a vehicle output. In some embodiments, the
vehicle output comprises a differential and a drive axle. In some
embodiments, the vehicle driveline comprises a torsional dampener
disposed between the engine and the variable transmission. In some
embodiments, the torsional dampener comprises at least one
torsional spring.
[0032] Provided herein is a method comprising switching between an
infinitely variable mode, a continuously variable mode, and a
direct drive mode using a variable transmission described herein or
that would be obvious to one of skill in the art upon reading the
disclosure herein.
[0033] Provided herein is a method comprising switching between an
infinitely variable mode and two continuously variable modes using
a variable transmission described herein or that would be obvious
to one of skill in the art upon reading the disclosure herein.
[0034] Provided herein is a method comprising switching between an
infinitely variable mode and three continuously variable modes
using a variable transmission described herein or that would be
obvious to one of skill in the art upon reading the disclosure
herein.
INCORPORATION BY REFERENCE
[0035] All publications, patents, and patent applications mentioned
in this specification are herein incorporated by reference to the
same extent as if each individual publication, patent, or patent
application was specifically and individually indicated to be
incorporated by reference.
BRIEF DESCRIPTION OF THE DRAWINGS
[0036] The novel features of the invention are set forth with
particularity in the appended claims. A better understanding of the
features and advantages of the present invention will be obtained
by reference to the following detailed description that sets forth
illustrative embodiments, in which the principles of the invention
are utilized, and the accompanying drawings of which:
[0037] FIG. 1 is a side sectional view of a continuously variable
planetary (CVP) transmission;
[0038] FIG. 2 is a magnified, side sectional view of a ball and
ring of the CVP transmission of FIG. 1;
[0039] FIG. 3 is a block diagram of a continuously variable
transmission (CVT) used in an automobile;
[0040] FIG. 4 is a block diagram of a continuously variable
transmission (CVT) according to an embodiment of the present
disclosure used in an automobile having both continuously variable
modes, a direct drive mode and an infinitely variable mode;
[0041] FIG. 5 is a graph of a speed diagram of the CVT of FIG.
4;
[0042] FIG. 6 is a block diagram of a continuously variable
transmission (CVT) according to another embodiment of the present
disclosure having a Ravigneaux gear set used in an automobile
having two continuously variable modes and an infinitely variable
mode;
[0043] FIG. 7 is a graph of a speed diagram of the CVT of FIG.
6;
[0044] FIG. 8 is a block diagram of a continuously variable
transmission (CVT) according to another embodiment of the present
disclosure having a Ravigneaux gear set used in an automobile
having three continuously variable modes and an infinitely variable
mode; and
[0045] FIG. 9 is a graph of a speed diagram of the CVT of FIG.
8.
DETAILED DESCRIPTION OF THE INVENTION
[0046] Continuously Variable Transmissions or CVTs are of many
types: belts with variable pulleys, toroidal, and conical, for
non-limiting example. The principle of a CVT is that it enables the
engine to run at its most efficient rotation speed by changing
steplessly the transmission ratio in function of the speed of the
car and the torque demand (throttle position) of the driver. If
needed for example when accelerating, the CVT can also shift to the
most optimum ratio providing more power. A CVT can change the ratio
from the minimum to the maximum ratio without any interruption of
the power transmission, as opposed to the opposite of usual
transmissions which require an interruption of the power
transmission by disengaging to shift from one discrete ratio to
engage the next ratio.
[0047] A specific use of CVTs is the Infinite Variable Transmission
or IVT. Where the CVT is limited at positive speed ratios, the IVT
configuration can perform a neutral gear and even reverse
steplessly. A CVT can be used as an IVT in some driveline
configurations.
[0048] Provided herein are configurations based on a ball type CVT,
also known as CVP (for constant variable planetary) or a variator,
herein. Aspects of an example CVT are described in US20060084549 or
AU2011224083A1, incorporated herein by reference in their entirety.
The type of CVT used herein is comprised a variator comprising a
plurality of variator balls, depending on the application, two
discs or annular rings (i.e. a first ring assembly and a second
ring assembly) each having an engagement portion that engages the
variator balls. The engagement portions may be in a conical or
toroidal convex or concave surface contact with the variator balls,
as input and output. The variator may include an idler contacting
the balls as well as shown on FIG. 1. The variator balls are
mounted on axes, themselves held in a cage or carrier allowing
changing the ratio by tilting the variator balls' axes. Other types
of ball CVTs also exist, like the one produced by Milner but are
slightly different. These alternative ball CVTs are additionally
contemplated herein. The working principle generally speaking, of a
ball-type variator of a CVT is shown in FIG. 2.
[0049] The variator itself works with a traction fluid. The
lubricant between the ball and the conical rings acts as a solid at
high pressure, transferring the power from the first ring assembly,
through the variator balls, to the second ring assembly. By tilting
the variator balls' axes, the ratio can be changed between input
and output. When the axis of each of the variator balls is
horizontal the ratio is one, when the axis is tilted the distance
between the axis and the contact point change, modifying the
overall ratio. All the variator balls' axles are tilted at the same
time with a mechanism included in the cage.
[0050] In a car, the CVT is used to replace traditional
transmission and is located between the engine (ICE or internal
combustion engine) and the differential as shown on FIG. 3. A
torsional dampener 2 (alternatively called a damper) may be
introduced between the engine 100 and the CVT to avoid transferring
torque peaks and vibrations that could damage the CVT. In some
configurations this dampener can be coupled with a clutch for the
starting function.
[0051] Embodiment variable transmissions (and resulting drivelines)
are shown in FIGS. 4, 6 and 8. Each of these configurations
comprises a variator. Such variator comprises a first ring
assembly, a second ring assembly, and a carrier assembly disposed
therebetween. The carrier assembly includes a plurality of variator
balls having tiltable axle shafts as described herein. In some
embodiments, the first ring assembly is rotatably disposed in a
housing; the first ring assembly comprises a first variator ball
engagement surface that is in driving engagement with a plurality
of variator balls of the carrier assembly.
[0052] A first variator ball engagement surface is formed in a
distal end of the first ring assembly. When describing a ring
assembly of a tilting ball variator, the term distally refers to
the portion of the ring assembly closest to the balls of the
variator. In some embodiments, the first variator ball engagement
surface is a conical surface or a concave or convex toroidal
surface in contact with or slightly spaced apart from each of the
variator balls. In some embodiments, the first variator ball
engagement surface is in driving engagement with each of the
variator balls of the carrier assembly through one of a boundary
layer type friction and an elastohydrodynamic film.
[0053] The carrier assembly of the variator may be rotatably
disposed in the housing and may be drivingly engaged with the first
ring assembly. The carrier assembly comprises an annular
arrangement of the plurality of tiltable variator balls each having
tiltable ball axle shafts. In some embodiments, each of the ball
axle shafts is adjusted using a cam style tilting mechanism. In
some embodiments, each of the ball axle shafts is adjusted using a
split carrier axle skewing mechanism.
[0054] As depicted in FIGS. 4, 6, and 8, a second ring assembly is
rotatably disposed in the housing. The second ring assembly
comprises a second variator ball engagement surface that is in
driving engagement with variator balls of the carrier assembly. In
some embodiments, the second variator ball engagement surface is
formed in a distal end of the second ring assembly. In some
embodiments, the second variator ball engagement surface is a
conical surface or a concave or convex toroidal surface in contact
with or slightly spaced apart from each of the variator balls. In
some embodiments, the second variator ball engagement surface is in
driving engagement with each of the variator balls of the carrier
assembly through one of a boundary layer type friction and an
elastohydrodynamic film.
[0055] A ball ramp on each side of the variator provides the
clamping force necessary to transfer the torque. Ball ramps,
indicated in FIGS. 4, 6, and 8 by a circle between a pair of
vertical lines, making up a first thrust ring on the first ring
assembly and a second thrust ring on the second ring assembly are
disposed between components of the variable transmission as shown
to generate an amount of axial force necessary for proper operation
of the variable transmission (i.e. transfer of torque); however, it
is understood that the amount of axial force necessary for proper
operation may be generated by a clamping mechanism (not shown) or
as a load applied during assembling of the variable transmission.
Thus, as depicted in FIGS. 4, 6, and 8, a ball ramp on each side of
the variator provides the clamping force necessary to transfer the
torque in this embodiment.
[0056] Provided herein is a series of configurations for a variable
transmission comprising: an input shaft; three planetary gear sets;
a variator comprising, a first ring assembly, a second ring
assembly, a carrier assembly; at least one of a brake or a clutch;
and the output shaft. Some of the configurations provided herein
may further comprise a Ravigneaux gear set.
[0057] In some embodiments, the variable transmission comprises a
continuously variable mode, an infinitely variable mode or a
combination thereof. In some embodiments, the variable transmission
comprises a direct drive mode.
[0058] In some embodiments the variable transmission provides an
input-coupled powersplit solution function.
[0059] In some embodiments, the transition between continuously
variable transmission mode and infinitely variable transmission
mode is accomplished by releasing or engaging one or more brakes,
and/or alternatively releasing or engaging one or more clutches
simultaneously.
[0060] In some embodiments, the variator is able to continuously
change its ratios in both the continuously variable mode and
infinitely variable mode to provide the best ratio achievable for
the engine to optimize power consumption.
[0061] Provided herein is a variable transmission comprising: an
input shaft; a first planetary gear set, a second planetary gear
set and a third planetary gear set; a variator comprising a first
ring assembly, a second ring assembly; a first clutch, a second
clutch and a third clutch; and a first brake comprising a first
brake member, wherein said input shaft is drivingly engaged with
the first ring assembly of the variator, and mechanically
coupleable to a first planetary sun of the first planetary gear set
using the second clutch; wherein said input shaft is also drivingly
engaged with a third sun of the third planetary gear set; wherein
the second ring assembly is drivingly engaged with a ring of the
third planetary gear set; wherein a first carrier of the first
planetary gear set and a second carrier of the second planetary
gear set are coupled together, wherein a third carrier of the third
planetary gear set is mechanically coupleable to the first carrier
of and the second carrier through the third clutch; wherein the
first brake member is coupled a second ring of the second planetary
gear; and wherein the first ring of the first planetary gear set is
mechanically coupled to the output of the transmission; wherein the
third carrier is mechanically coupled to the second sun of the
second planetary gear set; wherein the first sun of the first
planetary gear set might be coupled to the first ring of the first
planetary gear set with the first clutch.
[0062] In some embodiments, the variable transmission comprises two
continuously variable modes and an infinitely variable mode and a
direct drive mode. In some embodiments, the continuously variable
modes of claim 2 comprise a low speed (CVM1) and a high speed
(CVM2). In some embodiments, either or both of the continuously
variable modes are enabled by blocking rotation of a variator
carrier of the variator.
[0063] In some embodiments, power from the input shaft passes
through the variator and simultaneously passes to a vehicle output.
In some embodiments, wherein a slipping clutch is not required
between the input shaft and the variable transmission. In some
embodiments, wherein a torque converter is not required between the
input shaft and the variable transmission
[0064] In some embodiments, engaging the second clutch and the
first brake results in an infinitely variable mode. In some
embodiments, reverse and low positive speeds can be obtained when
the input shaft is directly engaged to the first sun of the first
planetary gear set by engaging a second clutch.
[0065] In some embodiments, engaging the first clutch and the first
brake at the second planetary gear set reduces speed of the second
ring assembly and allows the first planetary gear set to turn at a
1:1 ratio, thereby engaging a first continuously variable mode
(CVM1).
[0066] In some embodiments, engaging the first clutch and the third
clutch directly drives the variator second ring assembly linked to
the first carrier of the first planetary gear set through a 1:1
output ratio from the variator which drives output of the first
planetary gear set, thereby engaging a second continuously variable
mode (CVM2).
[0067] In some embodiments, engaging the first clutch and the third
clutch directly links the output of the first planetary gear set
(at the first ring) to the third carrier in a 1:1 output ratio
[0068] In some embodiments, engaging the second clutch and the
first brake engage an infinitely variable mode that allows
positive, negative speeds and powered neutral. (IVP).
[0069] In some embodiments, engaging the first clutch and the
second clutch bypasses the variator and allows output of the first
planetary gear set to turn at a 1:1 ratio with the input shaft,
directly engaging a vehicle output, thus engaging a direct drive
mode, In some embodiments, the direct drive mode is more efficient
than either of the two continuously variable modes. In some
embodiments, wherein native efficiency of the variable transmission
is increased by using the variator in a power-splitting
continuously variable mode.
[0070] Provided herein is a variable transmission comprising: an
input shaft; a variator comprising a first ring assembly, a second
ring assembly; a first planetary gear set, a second planetary gear
set and a third planetary gear set; a Ravigneaux gear set; a first
clutch; and a first brake and a second brake, wherein the input
shaft is drivingly engaged with a first sun of the first planetary
gear set having the second brake coupled to the ring of the first
planetary gear set; wherein the input shaft is drivingly engaged
with a second carrier of the second planetary gear set; wherein a
second sun of the second planetary gear set is coupled to the first
ring assembly of the variator, wherein the second ring assembly is
drivingly engaged with a third sun of the third planetary gear set,
the third ring of the third planetary gear set being fixed to
ground wherein a third carrier of the third planetary gear set is
drivingly engaged to a second ring of the second planetary gear
set; wherein a second ring of the second planetary is drivingly
engaged with the first sun of the Ravigneaux gear set, the
Ravigneaux gear set being mechanically coupled to the first brake
by its second sun; and wherein a carrier of the Ravigneaux gear set
is engaged with the first carrier of the first planetary gearset;
and wherein the ring of the Ravigneaux gear set is coupled to the
variable transmission output; and wherein a first clutch engages
the first sun of the Ravigneaux gear set to the carrier of the
Ravigneaux gear set.
[0071] In some embodiments, the first brake holds the second sun of
the Ravigneaux gear set. In some embodiments, the second brake
holds the first ring of the first planetary gear set. In some
embodiments, the ring of the Ravigneaux gear set is linked to a
first carrier of the first planetary gear set.
[0072] In some embodiments, the variable transmission comprises a
first continuously variable mode, a second continuously variable
mode, and an infinitely variable mode. In some embodiments, first
sun of the Ravigneaux gear set is engaged in all of the first
continuously variable mode, the second continuously variable mode,
and the infinitely variable mode to the carrier of the third
planetary gear set.
[0073] In some embodiments, the second brake is engaged to hold the
first ring of the first planetary gear set, thereby engaging the
infinitely variable mode. In some embodiments, the speed of second
ring of the Ravigneaux is reduced.
[0074] In some embodiments, when the first brake is engaged the
second sun is held which results in a first continuously variable
mode (CVM1) of operation.
[0075] In some embodiments, when the first clutch is engaged, the
Ravigneaux gear set is engaged which results in a second
continuously variable mode (CVM2) of operation. In some
embodiments, in the second continuously variable mode (CVM2) of
operation the entire Ravigneaux gear set turns at the same speed,
and achieves an efficient 1:1 ratio.
[0076] Provided herein is a variable transmission comprising: an
input shaft; a variator comprising a first ring assembly, a second
ring assembly; a first planetary gear set, a second planetary gear
set and a third planetary gear set; a Ravigneaux gear set; a first
clutch and a second clutch; and a first brake, a second brake, and
a third brake, wherein the input shaft is drivingly engaged with a
first sun of the first planetary gear set having the second brake
coupled to the ring of this first planetary gear set; wherein the
input shaft is drivingly engaged with a second carrier of the
second planetary gear set; wherein a second sun of the second
planetary gear set is coupled to the first ring assembly of the
variator, wherein the second ring assembly is drivingly engaged
with a third sun of the third planetary gear set, wherein the third
sun and the third carrier of the third planetary gear set are
coupled by a second clutch; wherein the third brake is coupled to
the third ring of the third planetary gear set; wherein the carrier
of the third planetary gear set is drivingly engaged with a second
ring of the second planetary gear set; wherein the second ring of
the second planetary gear set is drivingly engaged with a first sun
of the Ravigneaux gear set, the Ravigneaux gear set being coupled
to the first brake by its second sun and wherein a carrier of the
Ravigneaux gear set is engaged a first carrier of the first
planetary gearset; wherein a ring of the Ravigneaux gear set is
coupled to the variable transmission output; and wherein a first
clutch engages the first sun of the Ravigneaux gear set to the
carrier of the Ravigneaux gear set.
[0077] In some embodiments, the third brake is configured to
release a third ring of the third planetary gear set.
[0078] In some embodiments, the variable transmission comprises a
first continuously variable mode (CVM1), a second continuously
variable mode (CVM2), a continuously variable mode (CVM3), and an
infinitely variable mode.
[0079] In some embodiments, the first sun of the Ravigneaux gear
set is engaged to the carrier of the third planetary gear set in
each of the first continuously variable mode (CVM1), the second
continuously variable mode (CVM2), the continuously variable mode
(CVM3), and the infinitely variable mode.
[0080] In some embodiments, in the first continuously variable mode
(CVM1), or the second continuously variable mode (CVM2), the third
brake is engaged.
[0081] In some embodiments, in the infinitely variable mode the
third brake is engaged.
[0082] In some embodiments, in the third continuously variable mode
(CVM3), the third brake is disengaged, the first clutch is engaged,
and the second clutch is engaged.
[0083] In some embodiments, when the third sun of the third
planetary gear set and third carrier of the third planetary gear
set are coupled, the third planetary gear set is configured to turn
at a 1:1 ratio.
[0084] In some embodiments, the variator continuously changes its
torque ratios in the first continuously variable mode (CVM1), the
second continuously variable mode CVM2), the continuously variable
mode (CVM3), and the infinitely variable mode to optimize power
consumption.
[0085] In some embodiments, the variable transmission comprises a
traction fluid.
[0086] Provided herein is a vehicle driveline comprising a variable
transmission described herein or that would be obvious to one of
skill in the art upon reading the disclosure herein disposed
between an engine and a vehicle output. In some embodiments, the
vehicle output comprises a differential and a drive axle. In some
embodiments, the vehicle driveline comprises a torsional dampener
disposed between the engine and the variable transmission. In some
embodiments, the torsional dampener comprises at least one
torsional spring.
[0087] Provided herein is a method comprising switching between an
infinitely variable mode and a continuously variable mode using a
variable transmission described herein or that would be obvious to
one of skill in the art upon reading the disclosure herein.
[0088] Provided herein is a method comprising switching between an
infinitely variable mode and two continuously variable modes using
a variable transmission described herein or that would be obvious
to one of skill in the art upon reading the disclosure herein.
[0089] Provided herein is a method comprising switching between an
infinitely variable mode and three continuously variable modes
using a variable transmission described herein or that would be
obvious to one of skill in the art upon reading the disclosure
herein.
[0090] Provided herein is a vehicle comprising a variable
transmission described herein or that would be obvious to one of
skill in the art upon reading the disclosure herein disposed
between an engine and a vehicle output.
Example 1
[0091] The embodiment of FIG. 4 depicts a variable transmission 3a
comprising: a variator 8a comprising a first ring assembly 81ra, a
second ring assembly 82ra, with variator balls 8ba drivingly
engaged therebetween, typically mounted on a carrier (not shown); a
first planetary gear set 5a comprising a first sun gear 5sa
(sometimes simply referred to as "first sun"), a first ring gear
5ra (sometimes simply referred to as "first ring"), a first planet
carrier 5ca (also referred to as "first carrier"), and a first set
of planets gears 5pa; a second planetary gear set 6a comprising a
second sun gear 6sa (sometimes simply referred to as "second sun"),
a second ring gear 6ra (sometimes simply referred to as "second
ring"), a second planet carrier 6ca (also referred to as "second
carrier"), and a second set of planets gears 6pa, a third planetary
gear set 7a comprising a third sun gear 7sa (sometimes simply
referred to as "third sun"), a third ring gear 7ra (sometimes
simply referred to as "third ring"), a third planet carrier 7ca
(also referred to as "third carrier"), and a third set of planets
gears 7pa; a first clutch 10a; a second clutch 11a; a third clutch
12a; a first brake 13a; input shaft la; and output 50a.
[0092] The embodiment of FIG. 4 is an input-coupled powersplit
solution, meaning that a part of the power will pass through the
variator while the remaining power will pass to the output through
a mechanical path with higher efficiency. This power-splitting
permits a relatively small variator and an increase to the native
efficiency of the transmission. The central part of the
configuration is the variator 8a described previously in the
document. A ball ramp on each side of the variator provides the
clamping force necessary to transfer the torque. The variator is
only used in continuously variable mode by blocking rotation of the
variator carrier of the variator.
[0093] This configuration has an infinitely variable mode to
provide a standstill, reversed and starting function; two
continuously variable modes, one for low speeds and one for high
speeds; and a fuel efficient direct drive mode. No starting device
like a slipping clutch or torque converter is required, since the
IVP mode takes care of the starting function.
[0094] In the embodiment depicted in FIG. 4 a motor 100 such as an
internal combustion engine (ICE) is coupled to the variator first
ring assembly 81ra via input shaft 1a and can be linked to the
first sun 5sa of the first planetary gear set 5a with second clutch
11a. The ICE is also linked to the sun 7sa of third planetary gear
set 7a. The variator second ring assembly 82ra is coupled to the
ring 7ra of third planetary gear set 7a. The carrier 7ca of third
planetary gear set 7a can be directly linked to the carriers 5ca
and 6ca of first planetary gear set 5a and second planetary gear
set 6a with the use of the third clutch 12a, or the carrier 7ca can
be reduced in speed by applying the first brake 13a to the ring 6ra
of the second planetary gear set 6a. The ring 5ra of first
planetary gear set 5a is coupled to the output 50a of the variable
transmission 3a and goes directly to the differential 4. By
engaging the first clutch 10a, the first planetary gear set 5a
turns in an efficient 1:1 ratio. The carrier 7ca of third planetary
gear set 7a is directly linked to the sun 6sa of second planetary
gear set 6a.
[0095] As shown in FIG. 5, the three horizontal axes 501, 502, and
503 represent respectively, from the bottom to the top, the third
sun 7sa rotation speed, the first carrier 5ca rotation speed and
the first ring 5ra rotation speed. An example Motor 100 speed is
shown at point 505 for a reference. The output speed range of the
variable transmission in IVP mode is represented by the segment 520
between speeds 508 and 509 shown corresponding to the first ring
5ra speed. Speed 510 is shown which corresponds to the carrier 5ca
speed when the IVT mode is operating as a powered neutral. The
output speed range of the variable transmission 3a in CVM1 is
represented by the region 521 between speeds 506 and 507 shown on
axis 503. The output speed range for variable transmission 3a in
CVM2 is shown by the segment 522 between speeds 511 and 512. Note
that for CVM1 and CVM2 the output speeds are identical to the
corresponding speeds on axis 502 (shown connected by vertical
arrows). This is because in such modes the first ring 5ra and first
carrier 5ca are rotatably fixed to each other due to the engagement
of the first clutch 10a. In direct drive the output of the variable
transmission 3a matches the engine speed 505 at output speed
515.
[0096] In IVP mode, second clutch l la and first brake 13a are
closed (engaged). The sun 5sa of the first planetary gear set 5a
turns at motor 100 speed and the output speed of the variator is
reduced at the second planetary gear set 6a. This is then linked to
the first carrier 5ca of the first planetary gear set 5a. At the
first ring 5ra of the first planetary gear set 5a, (output to
differential) reversed and low positive speeds (IVP) when the ICE
is coupled to the first sun 5sa of the first planetary gear set 5a
by applying the second clutch 11a. In this mode, powersplitting
occurs two times. A part of the input power goes to the first sun
5sa of the first planetary gear set 5a and part of it goes to the
variator 8a. The latter then splits the power again, in a part
going to the variator first ring assembly 81ra and a part going to
the third sun 7sa of the third planetary gear set 7a.
[0097] In CVM1 mode, the first clutch 10a and first brake 13a are
applied. The output speed of the variator is reduced at the second
planetary gear set 6a. This is then linked to the first ring 5ra
(output to the differential) by applying the first clutch 10a,
allowing the first planetary gear set 5a to turn at a 1:1 ratio. In
this mode there is powersplitting.
[0098] In CVM2 mode, the first clutch 10a and third clutch 12a are
applied. The output speed of the variator is directly linked to the
first carrier 5ca of the first planetary 5a. This is then linked to
the output to the differential by applying the first clutch 10,
allowing the first planetary gear set 5a to turn at a 1:1 ratio. In
this mode there is powersplitting.
[0099] Direct drive mode provides an efficient way for high-speed
driving, like on the highway. It is obtained by engaging first
clutch 10a and second clutch 11a, therefore bypassing the CVP and
allowing the output planetary (first planetary gear set 5a) to turn
at a 1:1 ratio. The motor 100 is then directly linked to the
differential without powersplitting.
[0100] This device is able to change continuously its ratio to
provide the best ratio achievable for the engine in function of the
objectives of consumption of power. In a manual or automatic
transmission, only some predetermined and discrete ratios are
available and an interruption of the power transmission is needed
to shift of ratio. The only interruptions of power in this device
are the modes shifting. Other advantages of this configuration are
that a small variator can be chosen; spread is larger to a
traditional gearbox and the native efficiency of the transmission
is increased by using the variator in a powersplit device,
therefore letting a part of the power passing through a more
efficient mechanical path. This particular configuration has an
extra advantage by having an efficient direct drive mode for
cruising speeds, bypassing the less efficient variator.
Example 2
[0101] The embodiment of FIG. 6 depicts a variable transmission 3b
comprising: a variator 8b comprising a first ring assembly 81rb, a
second ring assembly 82rb, with variator balls 8bb drivingly
engaged therebetween, typically mounted on a carrier (not shown); a
first planetary gear set 5b comprising a first sun gear 5sb
(sometimes simply referred to as "first sun"), a first ring gear
5rb (sometimes simply referred to as "first ring"), a first planet
carrier 5cb (also referred to as "first carrier"), and a first set
of planets gears 5pb; a second planetary gear set 6b comprising a
second sun gear 6sb (sometimes simply referred to as "second sun"),
a second ring gear 6rb (sometimes simply referred to as "second
ring"), a second planet carrier 6cb (also referred to as "second
carrier"), and a second set of planets gears 6pb, a third planetary
gear set 7b comprising a third sun gear 7sb (sometimes simply
referred to as "third sun"), a third ring gear 7rb (sometimes
simply referred to as "third ring"), a third planet carrier 7cb
(also referred to as "third carrier"), and a third set of planets
gears 7pb; a Ravigneaux gear set 9b comprising a first Ravigneaux
sun 91sb, a second Ravigneaux sun 92sb, a planetary carrier 9cb, a
ring gear 9rb, a set of inner planet gears 93pb, and a set of outer
planet gears 94pb; a first clutch 10b; a first brake 13b; a second
brake 14b; input shaft 1b; and output 50b.
[0102] The embodiment depicted in FIG. 6 is an input and output
coupled powersplit solution, meaning that the powersplitting occurs
two times (only in infinitely variable mode, in the other modes it
is an output-coupled system only). Powersplitting occurs in
infinitely variable mode the first time at the first planetary gear
set 5b. Part of the power flows to the Ravigneaux gear set 9b and a
part flows to the second planetary gear set 6b. Powersplitting
occurs at the second planetary gear set 6b. Part of the power flows
through the less efficient variator 8b and a part flows through a
mechanical path to the third planetary gear set 7b. This power
splitting allows the embodiment have a relatively small variator
and to increase the native efficiency of the transmission. The
central part of that configuration is the variator described
previously in the document. A ball ramp on each side of the
variator provides the clamping force necessary to transfer the
torque. The variator is also only used in continuously variable
mode by always blocking rotation of the variator carrier of the
variator.
[0103] This configuration has an infinitely variable mode to
provide a standstill, reversed and starting function and two
continuously variable modes, one for low speeds and one for high
speeds. No starting device like a slipping clutch or torque
converter is required, since the infinitely variable mode takes
care of the starting function.
[0104] The motor 100, such as an ICE, is coupled to the first sun
5sb of the first planetary gear set 5b and to the second carrier
6cb of the second planetary gear set 6b. The second sun 6sb of the
second planetary gear set 6b is coupled to the variator first ring
assembly 81ra. The variator second ring assembly 82rb is then
coupled to the third sun 7sb of the third planetary gear set 7b,
the third planetary gear set being linked to the ground at its ring
7rb and to the second ring 6rb of the second planetary gear set 6b
by its carrier. The second ring 7rb of the second planetary gear
set 7b is coupled to the first sun 91sb of the Ravigneaux gear set
9b and can be coupled to the carrier 9cb of the Ravigneaux 9b by
engaging a first clutch 10b. By engaging that first clutch 10b, the
Ravigneaux 9b turns in an efficient 1:1 ratio. The carrier 9cb of
the Ravigneaux 9b is the coupled to the first carrier 6cb of the
first planetary gear box 6b. The ring 9rb of the Ravigneaux 9b is
coupled to the variable transmission output 50b which is coupled
directly to the final drive and differential (i.e. the vehicle
output). Two brakes, including first brake 13b and second brake 14b
allow either holding the second Ravigneaux sun 92sb of the
Ravigneaux 9b (by first brake 13b) or either the first ring 5rb of
the first planetary 5b (by second brake 14b).
[0105] FIG. 7 shows the speed diagram of the configuration of FIG.
6 (Example 2). As shown in FIG. 7, the four horizontal axes 701-704
represent respectively, from the bottom to the top, the first
Ravigneaux sun 91sb rotation speed, the Ravigneaux carrier 9cb
rotation speed, the second Ravigneaux ring 9rb rotation speed, and
the second Ravigneaux sun 92sb rotation speed. The variable
transmission output in infinitely variable mode spans the speeds
bounded by speeds 709 and 710 (at the ring 9rb). The variable
transmission output speeds in CVM1 span the speeds bounded by 710
and 711, while the variable transmission output speeds in CVM2 span
the speeds bounded by 711 and 712. As shown, these speed ranges
form a continuous overall output range. However this is dependent
upon the gear ratios chosen for the various elements of the
variable transmission. The speed ratios may be chosen such that
each mode's output ranges may or may not overlap. The output speed
is represented by the bolded horizontal line on the carrier
rotation speed line starting from the intersection of the first
dotted line and the bolded horizontal line, and ending on the
intersection of the second vertical dotted line and the bolded
horizontal line. The output speed powersplit is the speed at the
second ring assembly 82rb of the variator 8b and is bounded by
speeds 707 and 706 shown on axis 701. The motor speed 705 is shown
for reference as well.
[0106] The first Ravigneaux sun 91sb is coupled to the output of
the powersplit in the three modes. That powersplit output speed is
shown on the first Ravigneaux sun 91sb axis.
[0107] The infinitely variable mode is activated by engaging the
second brake 14b to hold the first ring 5rb of the first planetary
gear set 5b. The Ravigneaux carrier 9cb of the Ravigneaux 9b being
coupled to the first carrier 5cb of the first planetary gear set
5b, its speed is reduced to the point 708 shown on the axis 702. As
the ring 9rb is the output of the variable transmission, the output
speed achievable can be observed on the ring axis 703 of the speed
diagram.
[0108] The first continuously variable mode (CVM1) is activated by
holding the second Ravigneaux sun 92sb with the first brake 13b.
The speed achievable can be observed in the speed diagram between
speeds 710 and 711.
[0109] The second continuously variable mode (CVM2) is activated
when the first clutch 10b is engaged, doing this, the whole
Ravigneaux gear set 9b is turning at the same speed and achieving
an efficient 1:1 ratio.
Example 3
[0110] The embodiment of FIG. 8 demonstrates and comprises that a
mode can be added to that concept of Example 2 by adding one clutch
and one brake. The embodiment of FIG. 8 depicts a variable
transmission 3c comprising: a variator 8c comprising a first ring
assembly 81rc, a second ring assembly 82rc, with variator balls 8bc
drivingly engaged therebetween, typically mounted on a carrier (not
shown); a first planetary gear set 5c comprising a first sun gear
5sc (sometimes simply referred to as "first sun"), a first ring
gear 5rc (sometimes simply referred to as "first ring"), a first
planet carrier 5cc (also referred to as "first carrier"), and a
first set of planets gears 5pc; a second planetary gear set 6c
comprising a second sun gear 6sc (sometimes simply referred to as
"second sun"), a second ring gear 6rc (sometimes simply referred to
as "second ring"), a second planet carrier 6cc (also referred to as
"second carrier"), and a second set of planets gears 6pc, a third
planetary gear set 7c comprising a third sun gear 7sc (sometimes
simply referred to as "third sun"), a third ring gear 7rc
(sometimes simply referred to as "third ring"), a third planet
carrier 7cc (also referred to as "third carrier"), and a third set
of planets gears 7pc; a Ravigneaux gear set 9c comprising a first
Ravigneaux sun 91sc, a second Ravigneaux sun 92sc, a planetary
carrier 9cc, a ring gear 9rc, a set of inner planet gears 93pc, and
a set of outer planet gears 94pc; a first clutch 10c; a second
clutch 11c; a first brake 13c; and a second brake 14c; a third
brake 15c; input shaft 1c; and output 50c.
[0111] The additional clutch 11c is placed between the variator
second ring assembly 82rc and the third planetary gear set 7c
carrier 7cc (still coupled to the second planetary ring 6rc) and
the third brake 15c is allowed to release the third ring 7rc of the
third planetary gear set 7c.
[0112] FIG. 9 shows the speed diagram of the configuration of FIG.
8 (Example 3). As shown in FIG. 9, the four horizontal axes 901-904
represent respectively, from the bottom to the top, the first
Ravigneaux sun 91sc rotation speed, the second Ravigneaux carrier
9cc rotation speed, the ring 9rc rotation speed and the second
Ravigneaux sun 92sc rotation speed. In IVP mode the variable
transmission output speed at the ring 9rc is shown between speed
points 909 and 910. In CVM1 the variable transmission output speeds
are shown between speed points 910 and 911. In CVM2 the variable
transmission outputs speeds lie between speed points 911 and 912.
In CVM3 the variable transmission output speeds lie between speed
points 912-914. The speed ranges just enumerated depend upon the
gear ratios of the various components of the variable transmission.
The gear ratios may be chosen such that output speed ranges of the
various modes form a continuous range or a discontinuous range. The
speeds 907, 906, and 913 match the speeds 911, 912, and 913 in CVM2
and CVM3 because due to the engagement of the first clutch the sun
91sc and the ring 9rc are rotatably fixed to each other. The speed
range 907-913 may also correspond to the speed at the second ring
assembly 82rc of the variator 8c. An example motor speed 905 is
shown on axis 901 for reference.
[0113] The additional brake 15c is engaged in the three former
modes (IVP, CVM1, CVM2) while the additional clutch is released
11c.
[0114] To engage CVM3 mode, the third brake 15c is opened and the
second clutch 11c is engaged, as well as the first clutch 10c. The
sun 7sc and the third carrier 7cc of the third planetary gear set
7c are then coupled, making the third planetary gear set turn at an
efficient 1:1 ratio.
[0115] The variable transmission of embodiment of FIG. 8 is able to
change continuously its ratio to provide the best ratio achievable
for the engine in function of the objectives of consumption of
power. In a manual or automatic transmission, only some
predetermined and discrete ratios are available and an interruption
of the power transmission is needed to shift of ratio. The only
interruptions of power in the variable transmission of embodiment
of FIG. 8 are the modes shifting. Other advantages of this
configuration are that a small variator can be chosen; spread is
comparable (re: Example 2) or larger (re: Example 3) compared to a
traditional gearbox and the native efficiency of the transmission
is increased by using the variator in a powersplit device,
therefore letting a part of the power passing through a more
efficient mechanical path. This is especially true for the
infinitely variable mode, where powersplitting occurs two
times.
[0116] Embodiments of the variable transmission described herein or
that would be obvious to one of skill in the art upon reading the
disclosure herein, are contemplated for use in a variety of vehicle
drivelines. For non-limiting example, the variable transmissions
disclosed herein may be used in bicycles, mopeds, scooters,
motorcycles, automobiles, electric automobiles, trucks, sport
utility vehicles (SUV's), lawn mowers, tractors, harvesters,
agricultural machinery, all terrain vehicles (ATV's), jet skis,
personal watercraft vehicles, airplanes, trains, helicopters,
buses, forklifts, golf carts, motorships, steam powered ships,
submarines, space craft, or other vehicles that employ a
transmission. Provided herein is a vehicle comprising a variable
transmission described herein or that would be obvious to one of
skill in the art upon reading the disclosure herein disposed
between an engine and a vehicle output.
[0117] While the figures and description herein are directed to
ball-type variators (CVTs), alternate embodiments are contemplated
another version of a variator (CVT), such as a Variable-diameter
pulley (VDP) or Reeves drive, a toroidal or roller-based CVT
(Extroid CVT), a Magnetic CVT or mCVT, Ratcheting CVT, Hydrostatic
CVTs, Naudic Incremental CVT (iCVT), Cone CVTs, Radial roller CVT,
Planetary CVT, or any other version CVT.
[0118] While preferred embodiments of the present invention have
been shown and described herein, it will be obvious to those
skilled in the art that such embodiments are provided by way of
example only. Numerous variations, changes, and substitutions will
now occur to those skilled in the art without departing from the
invention. It should be understood that various alternatives to the
embodiments of the invention described herein may be employed in
practicing the invention. It is intended that the following claims
define the scope of the invention and that methods and structures
within the scope of these claims and their equivalents be covered
thereby.
* * * * *