U.S. patent application number 12/935549 was filed with the patent office on 2011-06-16 for double-clutch transmission for vehicles.
This patent application is currently assigned to GM GLOBAL TECHNOLOGY OPERATIONS, INC.. Invention is credited to Axel Geiberger, Mikael B. Mohlin, Mathias Remmler, Markus Rockenbach.
Application Number | 20110138943 12/935549 |
Document ID | / |
Family ID | 40671915 |
Filed Date | 2011-06-16 |
United States Patent
Application |
20110138943 |
Kind Code |
A1 |
Mohlin; Mikael B. ; et
al. |
June 16, 2011 |
DOUBLE-CLUTCH TRANSMISSION FOR VEHICLES
Abstract
A double-clutch transmission includes, but is not limited to an
inner input shaft inside an outer input shaft. Two clutch discs are
connected to the two input shafts, respectively. Three layshafts of
the DCT are parallel to the input shafts and one of the layshafts
has a pinion at en end. Gearwheels on the shafts include, but are
not limited to seven gearwheel groups for providing seven
sequentially increasing forward gears. Each of the groups comprises
a fixed gearwheel on the inner input shaft, meshing with an idler
gearwheel on one of the layshafts for providing a forward gear. A
fourth fixed gearwheel meshes with a fourth gear idler gearwheel
and a sixth gear idler gearwheel. Especially, the DCT further
includes, but is not limited to comprises the double-clutch
transmission that includes, but is not limited to a park-lock
gearwheel fixed onto one of the layshafts that carries a final
drive pinion.
Inventors: |
Mohlin; Mikael B.;
(Kungaelv, SE) ; Geiberger; Axel; (Mainz, DE)
; Remmler; Mathias; (Mauchenheim, DE) ;
Rockenbach; Markus; (Schweppenhausen, DE) |
Assignee: |
GM GLOBAL TECHNOLOGY OPERATIONS,
INC.
Detroit
MI
|
Family ID: |
40671915 |
Appl. No.: |
12/935549 |
Filed: |
March 31, 2009 |
PCT Filed: |
March 31, 2009 |
PCT NO: |
PCT/EP09/02353 |
371 Date: |
February 22, 2011 |
Current U.S.
Class: |
74/331 |
Current CPC
Class: |
Y10T 74/19233 20150115;
F16H 2200/0056 20130101; F16H 3/006 20130101; F16H 3/093 20130101;
Y10T 74/19065 20150115; F16H 2003/0931 20130101; Y10T 74/19112
20150115; F16H 2200/0086 20130101; Y10T 74/19228 20150115; F16H
2003/0826 20130101; F16H 2003/0822 20130101; Y10T 74/1907
20150115 |
Class at
Publication: |
74/331 |
International
Class: |
F16H 3/093 20060101
F16H003/093 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 31, 2008 |
EP |
08006486.8 |
Mar 31, 2008 |
EP |
08006569.1 |
Mar 31, 2008 |
EP |
08006606.1 |
Mar 31, 2008 |
EP |
08006607.9 |
Mar 31, 2008 |
EP |
08006608.7 |
Mar 31, 2008 |
EP |
08006609.5 |
Mar 31, 2008 |
EP |
08006610.3 |
Mar 31, 2008 |
EP |
08006611.1 |
Mar 31, 2008 |
EP |
08006612.9 |
Mar 31, 2008 |
EP |
08006613.7 |
Mar 31, 2008 |
EP |
08006614.5 |
Mar 31, 2008 |
EP |
08006615.2 |
Mar 31, 2008 |
EP |
08006616.7 |
Mar 31, 2008 |
EP |
08006617.8 |
Mar 31, 2008 |
EP |
08006618.6 |
Mar 31, 2008 |
EP |
08006619.4 |
Mar 31, 2008 |
EP |
08006620.2 |
Mar 31, 2008 |
EP |
08006621.0 |
Mar 31, 2008 |
EP |
08006622.8 |
Mar 31, 2008 |
EP |
08006623.6 |
Mar 31, 2008 |
EP |
08006624.4 |
Mar 31, 2008 |
EP |
08006625.1 |
Mar 31, 2008 |
EP |
08006626.9 |
Mar 31, 2008 |
EP |
08006627.7 |
Mar 31, 2008 |
EP |
08006628.5 |
Mar 31, 2008 |
EP |
08006629.3 |
Mar 31, 2008 |
EP |
08006630.1 |
Mar 31, 2008 |
EP |
08006631.9 |
Mar 31, 2008 |
EP |
08006632.7 |
Mar 31, 2008 |
EP |
08006633.5 |
Mar 31, 2008 |
EP |
08006634.3 |
Mar 31, 2008 |
EP |
08006635.0 |
Mar 31, 2008 |
EP |
08006636.8 |
Mar 31, 2008 |
EP |
08006637.6 |
Mar 31, 2008 |
EP |
08006638.4 |
Mar 31, 2008 |
EP |
08006639.2 |
Mar 31, 2008 |
EP |
08006640.0 |
Mar 31, 2008 |
EP |
08006641.8 |
Mar 31, 2008 |
EP |
08006642.6 |
Mar 31, 2008 |
EP |
08006643.4 |
Mar 31, 2008 |
EP |
08006644.2 |
Mar 31, 2008 |
EP |
08006645.9 |
Mar 31, 2008 |
EP |
08006646.7 |
Mar 31, 2008 |
EP |
08006647.5 |
Mar 31, 2008 |
EP |
08006648.3 |
Mar 31, 2008 |
EP |
08006649.1 |
Claims
1. A double-clutch transmission, comprising: an inner input shaft
and an outer input shaft, at least a portion of the inner input
shaft being surrounded by the outer input shaft; a first clutch
disc connected to the inner input shaft and a second clutch disc
connected to the outer input shaft; a first layshaft, a second
layshaft and a third layshaft spaced apart from the inner input
shaft and the outer input shafts and arranged substantially
parallel to the inner input shaft and the outer input shafts; at
least one of the first layshaft, the second layshaft, or the third
layshaft comprises a pinion; gearwheels arranged on the first
layshaft, on the second layshaft, the third layshaft, on the inner
input shaft and on the outer input shaft, the gearwheels comprising
a first gearwheel group, a second gearwheel group, a third
gearwheel group, a fourth gearwheel group, a fifth gearwheel group,
a sixth gearwheel group, a seventh gearwheel group adapted to
provide seven sequentially increasing forward gears, the first
gearwheel group comprising a first fixed gearwheel on the inner
input shaft, meshing with a first gear idler gearwheel on one of
the first layshaft, the second layshaft, or the third layshaft and
adapted to provide a first forward gear, the third gearwheel group
comprising a third fixed gearwheel on the inner input shaft,
meshing with a third gear idler gearwheel on one of the first
layshaft, the second layshaft, or the third layshaft and adapted to
provide a third forward gear, the fifth gearwheel group comprising
a fifth fixed gearwheel on the inner input shaft, meshing with a
fifth gear idler gearwheel on one of the first layshaft, the second
layshaft, or the third layshaft and adapted to provide a fifth
forward gear, the seventh gearwheel group comprising a seventh
fixed gearwheel on the inner input shaft, meshing with a seventh
gear idler gearwheel on one of the first layshaft, the second
layshaft, or the third layshaft adapted to provide a seventh
forward gear, the second gearwheel group comprising a second fixed
gearwheel on the outer input shafts, meshing with a second gear
idler gearwheel on one of the first layshaft, the second layshaft,
or the third layshaft and adapted to provide a second forward gear,
the fourth gearwheel group comprising a fourth fixed gearwheel on
the outer input shafts, meshing with a fourth gear idler gearwheel
on one of the first layshaft, the second layshaft, or the third
layshaft and adapted to provide a fourth forward gear, the sixth
gearwheel group comprising a sixth fixed gearwheel on the outer
input shafts, meshing with a sixth gear idler gearwheel on one of
the first layshaft, the second layshaft, or the third layshaft and
adapted to provide a sixth forward gear, and each gearwheel group
comprising a coupling device arranged on one of the first layshaft,
the second layshaft, or the third layshaft and adapted to
selectively engage one of the gearwheels for selecting one of the
seven gears, and the fourth fixed gearwheel further meshing with
the sixth gear idler gearwheel; a park-lock gearwheel fixed onto
one of the first layshaft, the second layshaft, or the third
layshafts that is adapted to carry a final drive pinion.
2. The double-clutch transmission according to claim 1, wherein one
of the fixed gearwheel of a lower gear is closer to the clutch disc
ends of the input shafts than another one of the fixed gearwheel of
a higher gear.
3. The double-clutch transmission according to claim 1, wherein one
of the idler gearwheels of a lower gear is closer to the pinion
than another one of the idler gearwheels of a higher gear on their
shared layshaft.
4. The double-clutch transmission according to claim 1, wherein the
first forward gear and the reverse gear are provided by the
different input shafts.
5. The double-clutch transmission device according to claim 1,
wherein the gearwheels further comprises a reverse gearwheel group
that comprises a reverse fixed gearwheel on one of the input
shafts, meshing with a first reverse gear wheel on the third
layshaft for receiving an input reverse torque, the reverse
gearwheel group further comprises a second reverse gear wheel on
the third layshaft that meshes with one of the idler gearwheels on
one of the first layshaft and the second layshaft for outputting
the received reverse torque to the pinion, and the reverse
gearwheel group further comprises a coupling device on one of the
layshafts to engage the gearwheels of the reverse gear for
selecting the reverse gear.
6. The double-clutch transmission device according to claim 1,
further comprising two pinions that are mounted on two of the
layshafts, respectively.
7. The double-clutch transmission device according to one of the
preceding claims, wherein at least two of the first gear idler
gearwheel, the second gear idler gearwheel, the third gear idler
gearwheel and the fourth gear idler gearwheel are mounted on one of
the same layshaft.
8. The double-clutch transmission device according to claim 1,
wherein at least two of the fifth gear idler gearwheel, the sixth
gear idler gearwheel and the seventh gear idler gearwheel are
mounted on one of the same layshaft.
9. The double-clutch transmission according to claim 1 further
comprising bearings adapted to support the layshafts, at least one
of the bearings being provided next to the pinion.
10. The double-clutch transmission according to claim 8, wherein at
least one of the bearings is provided next to one of the driven
gearwheels of low gears and the reverse gear.
11. A gearbox comprising: double-clutch transmission, the
double-clutch transmission comprising: an inner input shaft and an
outer input shaft, at least a portion of the inner input shaft
surrounded by the outer input shaft; a first clutch disc connected
to the inner input shaft and a second clutch disc connected to the
outer input shaft; a first layshaft, a second layshaft and a third
layshaft spaced apart from the inner input shaft and the outer
input shaft and arranged substantially parallel to the inner input
shaft and the outer input shaft; at least one of the first
layshaft, the second layshaft, or the third layshaft comprises a
pinion; gearwheels arranged on the first layshaft, on the second
layshaft, on the third layshaft, on the inner input shaft, and on
the outer input shaft, the gearwheels comprising a first gearwheel
group, a second gearwheel group, a third gearwheel group, a fourth
gearwheel group, a fifth gearwheel group, a sixth gearwheel group,
a seventh gearwheel group adapted to provide seven sequentially
increasing forward gears, the first gearwheel group comprising a
first fixed gearwheel on the inner input shaft, meshing with a
first gear idler gearwheel on one of the first layshaft, the second
layshaft, or the third layshaft and adapted to provide a first
forward gear, the third gearwheel group comprising a third fixed
gearwheel on the inner input shaft, meshing with a third gear idler
gearwheel on one of the first layshaft, the second layshaft, or the
third layshaft and adapted to provide a third forward gear, the
fifth gearwheel group comprising a fifth fixed gearwheel on the
inner input shaft, meshing with a fifth gear idler gearwheel on one
of the first layshaft, the second layshaft, or the third layshaft
and adapted to provide a fifth forward gear, the seventh gearwheel
group comprising a seventh fixed gearwheel on the inner input
shaft, meshing with a seventh gear idler gearwheel on one of the
first layshaft, the second layshaft, or the third layshaft and
adapted to provide a seventh forward gear, the second gearwheel
group comprising a second fixed gearwheel on the outer input
shafts, meshing with a second gear idler gearwheel on one of the
first layshaft, the second layshaft, or the third layshaft and
adapted to provide a second forward gear, the fourth gearwheel
group comprising a fourth fixed gearwheel on the outer input
shafts, meshing with a fourth gear idler gearwheel on one of the
first layshaft, the second layshaft, or the third layshaft and
adapted to provide a fourth forward gear, the sixth gearwheel group
comprising a sixth fixed gearwheel on the outer input shafts,
meshing with a sixth gear idler gearwheel on one of the first
layshaft, the second layshaft, or the third layshafts and adapted
to provide a sixth forward gear, and each gearwheel group
comprising a coupling device arranged on one of the first layshaft,
the second layshaft, or the third layshaft and adapted to
selectively engage one of the gearwheels for selecting one of the
seven gears, and the fourth fixed gearwheel further meshing with
the sixth gear idler gearwheel; a park-lock gearwheel fixed onto
one of the first layshaft, the second layshaft, or the third
layshafts that is adapted to carry a final drive pinion; and an
output gearwheel on an output shaft that meshes with the pinions
for outputting a drive torque to a torque drain.
12. The power train device according to claim 11, the power train
device further comprising at least one power source for generating
a driving torque.
13. The power train device according to claim 12, wherein the power
source comprises a combustion engine.
14. The power train device of claim 12, wherein the power source
comprises an electric motor.
15. (canceled)
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a U.S. National-Stage entry under 35
U.S.C. .sctn.371 based on International Application No.
PCT/EP2009/002353, filed Mar. 31, 2009, which was published under
PCT Article 21(2) and which claims priority to European Application
No. 08006645.9, filed Mar. 31, 2008, and which claims priority to
European Application No. 08006638.4, filed Mar. 31, 2008, and which
claims priority to European Application No. 08006639.2, filed Mar.
31, 2008, and which claims priority to European Application No.
08006640.0, filed Mar. 31, 2008, and which claims priority to
European Application No. 08006641.8, filed Mar. 31, 2008, and which
claims priority to European Application No. 08006642.6, filed Mar.
31, 2008, and which claims priority to European Application No.
08006635.0, filed Mar. 31, 2008, and which claims priority to
European Application No. 08006643.4, filed Mar. 31, 2008, and which
claims priority to European Application No. 08006644.2, filed Mar.
31, 2008, and which claims priority to European Application No.
08006486.8, filed Mar. 31, 2008, and which claims priority to
European Application No. 08006606.1, filed Mar. 31, 2008, and which
claims priority to European Application No. 08006607.9, filed Mar.
31, 2008, and which claims priority to European Application No.
08006608.7, filed Mar. 31, 2008, and which claims priority to
European Application No. 08006646.7, filed Mar. 31, 2008, and which
claims priority to European Application No. 08006616.7, filed Mar.
31, 2008, and which claims priority to European Application No.
08006617.8, filed Mar. 31, 2008, and which claims priority to
European Application No. 08006609.5, filed Mar. 31, 2008, and which
claims priority to European Application No. 08006610.3, filed Mar.
31, 2008, and which claims priority to European Application No.
08006611.1, filed Mar. 31, 2008, and which claims priority to
European Application No. 08006612.9, filed Mar. 31, 2008, and which
claims priority to European Application No. 08006621.0, filed Mar.
31, 2008, and which claims priority to European Application No.
08006622.8, filed Mar. 31, 2008, and which claims priority to
European Application No. 08006623.6, filed Mar. 31, 2008, and which
claims priority to European Application No. 08006624.4, filed Mar.
31, 2008, and which claims priority to European Application No.
08006569.1, filed Mar. 31, 2008, and which claims priority to
European Application No. 08006637.6, filed Mar. 31, 2008, and which
claims priority to European Application No. 08006615.2, filed Mar.
31, 2008, and which claims priority to European Application No.
08006636.8, filed Mar. 31, 2008, and which claims priority to
European Application No. 08006625.1, filed Mar. 31, 2008, and which
claims priority to European Application No. 08006626.9, filed Mar.
31, 2008, and which claims priority to European Application No.
08006627.7, filed Mar. 31, 2008, and which claims priority to
European Application No. 08006628.5, filed Mar. 31, 2008, and which
claims priority to European Application No. 08006629.3, filed Mar.
31, 2008, and which claims priority to European Application No.
08006630.1, filed Mar. 31, 2008, and which claims priority to
European Application No. 08006631.9, filed Mar. 31, 2008, and which
claims priority to European Application No. 08006619.4, filed Mar.
31, 2008, and which claims priority to European Application No.
08006620.2, filed Mar. 31, 2008, and which claims priority to
European Application No. 08006618.6, filed Mar. 31, 2008, and which
claims priority to European Application No. 08006614.5, filed Mar.
31, 2008, and which claims priority to European Application No.
08006613.7, filed Mar. 31, 2008, and which claims priority to
European Application No. 08006634.3, filed Mar. 31, 2008, and which
claims priority to European Application No. 08006633.5, filed Mar.
31, 2008, and which claims priority to European Application No.
08006632.7, filed Mar. 31, 2008, and which claims priority to
European Application No. 08006649.1, filed Mar. 31, 2008, and which
claims priority to European Application No. 08006648.3, filed Mar.
31, 2008, and which claims priority to European Application No.
08006647.5, filed Mar. 31, 2008, which are all hereby incorporated
in their entirety by reference.
TECHNICAL FIELD
[0002] The present application relates to a double-clutch
transmission for vehicles, such as cars.
BACKGROUND
[0003] A double-clutch transmission (DCT) comprises two input
shafts that are connected to and actuated by two clutches
separately. The two clutches are often combined into a single
device that permits actuating any of the two clutches at one time.
The two clutches transmit driving torque from an engine to the two
input shafts of the double-clutch transmission.
[0004] Volkswagen has provided a 7-speed dual clutch gearbox
(DSG.RTM.), namely DQ200. The DSG.RTM. DQ200 provides an attempt to
provide a 7-speed dual clutch gearbox in the cars for street
driving.
[0005] The DCT has not yet been widely used in cars for street
driving. Problems that hinder the application of DCT for street
driving comprise a provision of a compact, reliable, and
fuel-efficient DCT. Therefore, there exists a need for providing
such a DCT that is also affordable by consumers.
SUMMARY
[0006] The present application provides a double-clutch
transmission (DCT) that comprises an inner input shaft and an outer
input shaft. The outer input shaft surrounds a portion of the inner
input shaft. The outer input shaft surrounds the inner input shaft
in a radial direction. The radial direction indicates regions that
surround a longitudinal axis of the inner input shaft. The outer
input shaft can be a hollow input shaft and the inner input shaft
can be a solid input shaft. Alternatively, the inner input shaft
can also be a hollow input shaft.
[0007] The DCT comprises a first clutch disc that is connected
non-rotatably to the inner input shaft and a second clutch disc
that is also connected non-rotatably to the outer input shaft. For
example, the first clutch disc is fixed to the inner input shaft
and the second clutch disc is fixed to the outer input shaft.
Alternatively, a universal joint can provide the non-rotatable
connection.
[0008] The DCT has a first layshaft, a second layshaft, and a third
layshaft that are spaced apart from the input shafts and arranged
in parallel to the input shafts. That is, longitudinal axes of
these shafts are parallel to each other, including overlapping
axes. One of more of the layshafts comprises a pinion as a final
drive. The pinion can mesh with an output gear wheel on an output
shaft for outputting a drive torque to a drive train of a vehicle.
The drive train can alternatively be referred as powertrain or
powerplant that comprises the group of components for generating
power and for delivering it to the road surface, water, or air. The
drive train can include an engine, a transmission, drive shafts,
differentials, and a final drive. The final drive can include drive
wheels, continuous track that is used in tanks or caterpillar
tractors, or propeller.
[0009] Gearwheels of the DCT are arranged on the first layshaft, on
the second layshaft, on the third layshaft, on the inner input
shaft and on the outer input shaft. These gearwheels comprise a
first gearwheel group, a second gearwheel group, a third gearwheel
group, a fourth gearwheel group, a fifth gearwheel group, a sixth
gearwheel group, and a seventh gearwheel group for providing seven
sequentially increasing forward gears. The gear of the DCT can
refer to an output speed range of the output gear wheel. The
sequentially increasing gears describe an escalating order that
members of the order follow each other. Gears of a car can be
arranged in a sequentially increasing manner from a first gear to a
seventh gear. Gear ratios of the DCT decrease from the first gear
to the seventh gear correspondingly. For example, in a car having a
DCT of seven gears, a first gear has a gear ratio of 2.97:1. A
second gear has a gear ratio of 2.07:1. A third gear has a gear
ratio of 1.43:1. A fourth gear has a gear ratio of 1.00:1. A fifth
gear has a gear ratio of 0.84:1. A sixth gear has a gear ratio of
0.56:1. Lastly, a seventh gear has a gear ratio of 0.32:1. The
seven gears provide an increasing order of output speed ranges of
the transmission for driving a car with the DCT.
[0010] The first gearwheel group comprises a first fixed gearwheel
on the inner input shaft, meshing with a first gear idler gearwheel
on one of the layshafts for providing a first forward gear. The
third gearwheel group comprises a third fixed gearwheel on the
inner input shaft, meshing with a third idler gearwheel on one of
the layshafts for providing a third forward gear. The fifth
gearwheel group comprises a fifth fixed gearwheel on the inner
input shaft, meshing with a fifth gear idler gearwheel on one of
the layshafts for providing a fifth forward gear. The seventh
gearwheel group comprises a seventh fixed gearwheel on the inner
input shaft, meshing with a seventh gear idler gearwheel on one of
the layshafts for providing a seventh forward gear.
[0011] The second gearwheel group comprises a second fixed
gearwheel on the outer input shafts, meshing with a second gear
idler gearwheel on one of the layshafts for providing a second
forward gear. The fourth gearwheel group comprises a fourth fixed
gearwheel on the outer input shafts, meshing with a fourth gear
idler gearwheel on one of the layshafts for providing a fourth
forward gear. The sixth gearwheel group comprises a sixth fixed
gearwheel on the outer input shafts, meshing with a sixth gear
idler gearwheel on one of the layshafts for providing a sixth
forward gear.
[0012] One or more gearwheel groups comprise a coupling device
which is arranged on one of the layshafts to selectively engage one
of the gearwheels for selecting one of the seven gears. The fourth
fixed gearwheel further meshes with the six gear idler
gearwheel.
[0013] Especially, the double-clutch transmission further comprises
a park-lock gearwheel fixed onto one of the layshafts that carries
the pinion as a final drive pinion. The layshaft with the park-lock
comprises the final drive pinion for engaging and for locking a
differential of the DCT. The differential comprises the output
gearwheel on the output shaft. The park-lock enables a vehicle with
the park-lock to park at a place in a secure manner, even on a
slope. The park-lock is easy to implement and beneficial for the
vehicle and passengers' safety.
[0014] The DCT provides seven forward gears through a dual clutch.
The DCT makes gear switching between odd and even ratios to be
swift and efficient because the gearwheels of the odd and even
gears are driven by different clutch discs or by different clutches
respectively. One double meshing feature is provided by the fourth
fixed gearwheel that meshes with the fourth gear idler gearwheel
and the sixth gear idler gearwheel. The double meshing feature
makes the DCT to be compact and lightweight at low cost because two
fixed gearwheels are avoided on the input shafts. An idler
gearwheel and a coupling device together can replace a fixed
gearwheel on one of the input shafts. Similarly, an idler gearwheel
on one of the layshafts can be replaced by a fixed gearwheel if an
idler together with a coupling device are provided on one of the
input shafts for meshing with the fixed gearwheel on one of the
layshafts.
[0015] In the application, one of the fixed gearwheels of a lower
gear on one of the input shafts can be mounted closer to clutch
disc ends of the input shafts than another one of the fixed
gearwheel of a higher gear. The clutch disc ends of the input
shafts are the ends of the input shafts for coupling with the two
clutch discs. Idler gearwheels of the lower gears on one of the
layshafts are larger than that of higher gears. Since a
clutch-housing has a large compartment around the pinions and the
clutch disc ends, the compartment can be utilized to enclose the
larger idler gearwheels of lower gears. As result, the clutch
housing that encloses ends of layshafts without the pinions can be
made with smaller, which enables the double-clutch transmission to
be more compact. Therefore, it is beneficial to have an idler
gearwheel of a lower gear closer to a pinion on a same
layshaft.
[0016] Since the idler and fixed gearwheels of the same gear mesh
with each other, it is beneficial to mount a fixed gearwheel of a
lower gear on the input shaft to be closer to the clutch disc ends
of the input shafts.
[0017] In one embodiment, the application can provide the seventh
gear idler gearwheel on the second layshaft to be the most remote
from the pinion, as compared to other idlers on the same layshaft.
In another embodiment, the application can provide the seventh
fixed gearwheel to be more remote to the clutch disc ends of the
input shafts than the first fixed gearwheel.
[0018] One of the idler gearwheels of a lower gear is closer to the
pinion than another one of the idler gearwheels of a higher gear on
their shared layshaft.
[0019] In the application, the two different input shafts can drive
or provide the first forward gear and the reverse gear separately.
Dual clutches of the DCT enables that the switching between the two
input shafts can be achieved quickly. As a result, a driving scheme
that the DCT engages the two input shafts alternatively can drive
the vehicle back & forth rapidly. This scheme is useful for
moving the vehicle out of a muddy puddle because the vehicle can
simply be driven back & forth to get out the puddle. Less loss
of momentum of the gearwheels and the layshafts of the DCT can be
achieved. Alternatively, the back and forth movements can be
provided by a second forward gear and a first reverse gear on
different input shafts.
[0020] The gearwheels can further comprise a reverse gearwheel
group that comprises a reverse fixed gearwheel on one of the input
shafts, meshing with a first reverse gear wheel on the third
layshaft for receiving an input reverse torque. The reverse
gearwheel group can further comprise a second reverse gear wheel on
the third layshaft that meshes with one of the idler gearwheels on
one of the first layshaft and the second layshaft for outputting
the received reverse torque to the pinion. The reverse gearwheel
group can further comprise a coupling device on one of the
layshafts to engage the gearwheels of the reverse gear for
selecting the reverse gear. The reverse gear makes the vehicle with
the DCT to be more maneuverable.
[0021] The double-clutch transmission device can comprise two
pinions that are mounted on two of the layshafts respectively. The
two pinions can mesh or comb with one relatively big output
gearwheel on an output shaft. The output gearwheel can be
integrated into a transmission differential device without
providing an intermediate output shaft of the transmission gearbox.
This allows a very dense packaging situation for the DCT.
[0022] According to the application, two or more of the first gear
idler gearwheel, the second gear idler gearwheel, and the third
gear idler gearwheel are mounted on the same layshaft. Putting
idler gearwheels of low gears, such as idler gearwheels of the
first, second and third gears, on the same shaft require the
layshaft to be strong and sturdy. Remaining layshafts of the
double-clutch transmission can thus be made slim at low cost for
carrying gearwheels of high gears, except the layshaft carrying
reverse gear idler gearwheel. For example, two or more the fourth
gear idler gearwheel, the fifth gear idler gearwheel, the sixth
gear idler gearwheel and the seventh gear idler gearwheel are
mounted on the same layshaft.
[0023] The double-clutch transmission can further comprise bearings
for supporting the layshafts. One or more of the bearings is
provided next to the pinion. The immediate adjacent bearing reduces
deflection of the layshaft under load to better support the pinion
that outputs torque of its carrying layshaft. The supporting
bearing thus can improve torque transmission efficiency and reduce
cost of the DCT.
[0024] One or more the bearings are provided next to one of the
driven gearwheels of low gears. Gearwheels of low gears transmit
larger torques as compared to the gearwheels of high gears. Close
support of the bearings help to reduce excessive deflection and
weight related cost of their carrying shafts.
[0025] The application provides a gearbox that comprises the
double-clutch transmission and an output gearwheel on an output
shaft. The output gearwheel meshes with the pinion for outputting a
drive torque to a torque drain. The output gearwheel can even mesh
with each of the pinions. The output gearwheel provides a single
source of torque output so that the construction of the DCT is made
simple and neat.
[0026] The application provides a power train device with the
gearbox. One or more of power source generates a driving torque.
The power train device usually has the gearbox and the power source
onboard so that a vehicle with the power train device can be mobile
without being physically attached to an external stationary power
source.
[0027] The power source can comprise a combustion engine. The power
train with the combustion engine and the DCT is easy to
manufacture. The combustion engine can consume less petrol for
environmental protection. Furthermore, a combustion engine usable
for other types of fuel can have even less polluting emission, such
as hydrogen fuel.
[0028] The power source can comprise an electric motor. Electric
motor used in a hybrid car, or in an electrical car enables
reduction of pollution, as compared to typical combustion using
petrol. The electric motor can even recuperate brake energy in a
generator mode.
[0029] The application also provides a vehicle that comprises the
power train device. The vehicle having the power train device is
efficient in energy usage by using the DCT.
[0030] The double clutch transmission enables pre-selection of
gears for smooth gear transmission. Two coupling devices can engage
the idler gearwheel of the current gear and the idler gearwheel of
the next sequential gear at the same time. This allows the next
sequential gear to be connected rapidly and thus in a more smooth
manner. In particular, the two idlers of two consecutive gears that
are driven by different input shafts of the DCT can be both engaged
simultaneously. For example, idler gearwheels of the fourth gear
and the fifth gear of the DCT can be both engaged to their
weight-carrying layshaft by their respectively coupling devices
when one of the input shafts receives an input torque. One engaged
idler gearwheel is driven directly by the input torque whilst the
other engaged idler gearwheel is driven via the pinion by the input
torque. In this manner, little or no interruption in torque flow
during gearshift. Therefore, the double-clutch transmission
provides continuous and more efficient torque transmission, as
compared to other gearshift process.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] The present invention will hereinafter be described in
conjunction with the following drawing figures, wherein like
numerals denote like elements, and
[0032] FIG. 1 illustrates a front view of a first embodiment of a
double clutch transmission of the application;
[0033] FIG. 2 illustrates the path of torque flow of a first gear
transmission ratio;
[0034] FIG. 3 illustrates the path of torque flow of a second gear
transmission ratio;
[0035] FIG. 4 illustrates the path of torque flow of a third gear
transmission ratio;
[0036] FIG. 5 illustrates the path of torque flow of a fourth gear
transmission ratio;
[0037] FIG. 6 illustrates the path of torque flow of a fifth gear
transmission ratio;
[0038] FIG. 7 illustrates the path of torque flow of a sixth gear
transmission ratio;
[0039] FIG. 8 illustrates the path of torque flow of a seventh gear
transmission ratio;
[0040] FIG. 9 illustrates the path of torque flow of a reverse gear
transmission ratio;
[0041] FIG. 10 illustrates an assembly of a double-sided coupling
device with its neighboring gearwheels for engagement;
[0042] FIG. 11 illustrates an assembly of a single-sided coupling
device with its neighboring gearwheel for engagement;
[0043] FIG. 12 illustrates an assembly of an idler gearwheel that
is rotatably supported by a shaft on a bearing;
[0044] FIG. 13 illustrates an assembly of a fixed gearwheel that is
supported on a shaft;
[0045] FIG. 14 illustrates a cross-section through a detail of a
crankshaft of an internal combustion engine according to embodiment
of the double-clutch transmission;
[0046] FIG. 15 illustrates a front view of a further embodiment of
a double clutch transmission of the application;
[0047] FIG. 16 illustrates an expanded side view of the double
clutch transmission of FIG. 15;
[0048] FIG. 17 illustrates a front view of a further embodiment of
a double clutch transmission of the application; and
[0049] FIG. 18 illustrates an expanded side view of the double
clutch transmission of FIG. 17.
DETAILED DESCRIPTION
[0050] The following detailed description is merely exemplary in
nature and is not intended to limit application and uses.
Furthermore, there is no intention to be bound by any theory
presented in the preceding background or summary or the following
detailed description.
[0051] In the following description, details are provided to
describe the embodiments of the application. It shall be apparent
to one skilled in the art, however, that the embodiments may be
practiced without such details.
[0052] FIGS. 1-14 provide detailed description of an embodiment of
a double clutch transmission (DCT) of the application. FIGS. 1-14
comprise similar parts that have similar reference numbers.
Relevant description of the similar parts is incorporated where
necessary.
[0053] FIG. 1 illustrates a front view of an embodiment of a double
clutch transmission 1 of the application. The DCT 1 comprises a
reverse gear idler shaft 38, an upper pinion 41 on an upper
layshaft 40, two input shafts 20, 22, a lower pinion 51 on a lower
layshaft 50, and a relatively large output gearwheel 12 on an
output shaft 14. The two input shafts 20, 22 comprise an inner
input shaft 20 and an outer input shaft 22. The inner input shaft
20 is a solid input shaft 20 (i.e. K1) and the outer input shaft is
a hollow input shaft 22 (i.e. K2). The solid input shaft 20 and the
hollow input shaft 22 share the same longitudinal axis of rotation.
The two pinions 41, 51 are fixed to right ends of the upper
layshaft 40 and the lower layshaft 50 respectively. The output
gearwheel 12 is also fixed to the output shaft 14 along its
longitudinal axis. The two pinions 41, 51 mesh with the output
gearwheel 12 separately at different positions of the output
gearwheel 12.
[0054] The reverse gear idler shaft 38, the upper layshaft 40, and
the lower layshaft 50 are parallel to the coaxial input shafts 20,
22 with predetermined distances in-between. The distances are
provided in radial directions of these shafts respectively, which
is better seen in FIG. 2. Other gearwheels are mounted on these
shafts that mesh with each other according to predetermined
manners. These manners are better seen in some of the following
figures.
[0055] FIG. 1 further shows a cutting plane A-A for illustrating an
expanded cross-section view through the DCT 1, which is shown in
FIGS. 2 to 9. The cutting plane A-A passes through the rotational
axes of the reverse gear shaft 38, the upper layshaft 40, the input
shafts 20, 22, the lower layshaft 50, and the output shaft 14. One
of the goals of FIGS. 2 to 9 is to illustrate further structure and
torque flows of the DCT 1.
[0056] FIG. 2 illustrates the expanded view of the DCT that shows
the manners of the gearwheels mounting, which corresponds to FIG.
1.
[0057] According to FIG. 2, the DCT 1 comprises the following
shafts, from top to bottom, the reverse gear shaft 38, the upper
layshaft 40, the hollow input shaft 22, the solid input shaft 20,
the lower layshaft 50, and the output shaft 14. The solid input
shaft 20 is partially disposed inside the hollow input shaft 22.
The solid input shaft 20 also protrudes outside the hollow input
shaft 22 at two ends. The hollow input shaft 22 is mounted onto the
solid input shaft 20 by a pair of solid shaft bearings 71 that are
disposed between the solid input shaft 20 and the hollow input
shaft 22 at two ends of the hollow input shaft 22. As a result, the
two input shafts 20, 22 are coupled together such that the solid
input shaft 20 is free to rotate inside the hollow input shaft 22.
The hollow input shaft 22 surrounds a right portion of the solid
input shaft 20, and a left portion of the solid input shaft 20 is
exposed outside the hollow input shaft 22. The assembly of the
input shafts 20, 22 is supported by the solid shaft bearing 71 at a
protruding end of the solid shaft 20 on the left and by the hollow
shaft bearing 72 on the hollow input shaft 22 on the right.
[0058] According to FIG. 2, the outer input shaft 22 in a radial
direction of the solid input shafts 20 surrounds a portion of the
solid input shaft 20. The radial direction is perpendicular to the
common longitudinal axes of the input shafts 20, 22. There are four
gearwheels fixed on the left exposed portion of the solid input
shaft 20. These gearwheels are a fixed wheel first gear 24, a fixed
wheel seventh gear 27, a fixed wheel third gear 25 and a fixed
wheel fifth gear 26 from right to left sequentially. Each of the
fixed wheel first gear 24, the fixed wheel seventh gear 27, the
fixed wheel third gear 25 and the fixed wheel fifth gear 26 is
mounted onto the solid input shaft 20 coaxially. On the hollow
input shaft 22, which is mounted on the right portion of the solid
input shaft 20, there are attached with a fixed wheel fourth gear
31 and a fixed wheel second gear 30 from left to right. The fixed
wheel fourth gear 31 also serves as a fixed wheel sixth gear 32.
Each of the fixed wheel fourth gear 31 and the fixed wheel second
gear 30 is fixed onto the hollow input shaft 22 coaxially.
[0059] The upper layshaft 40 is provided above the input shafts 20,
22. There are gearwheels, coupling devices and bearings provided on
the upper layshaft 40. These includes, from right to the left, the
upper pinion 41, a layshaft bearing 73, a reverse gear idler wheel
37, a double-sided coupling device 81, an idler sixth gear 65, an
idler fifth gear 64, a double-sided coupling device 82, an idler
seventh gear 66, and a layshaft bearing 73.
[0060] The reverse gear idler wheel 37, the idler sixth gear 65,
the idler fifth gear 64, and the idler seventh gear 66 are mounted
on the upper layshaft 40 by bearings respectively such that these
gearwheels are free to rotate around the upper layshaft 40. The
double-sided coupling device 81 can move along the upper layshaft
40 to engage any of the 37 and the 65 to the upper layshaft 40.
Similarly, the double-sided coupling device 82 can move along the
upper layshaft 40 to engage any of the idler fifth gear 64 and the
idler seventh gear 66 to the upper layshaft 40. The idler sixth
gear 65 meshes with the fixed wheel sixth gear 32. The idler fifth
gear 64 meshes with the fixed wheel fifth gear 26. The idler
seventh gear 66 meshes with the fixed wheel seventh gear 27.
[0061] The reverse gear idler shaft 38 is provided further above
the upper layshaft 40. An idle shaft bearing 74, a first reverse
gear wheel 35, a second reverse gear wheel 36 and an idle shaft
bearing 74 are mounted onto the reverse gear shaft 38 from right to
left. Both the first reverse gear wheel 35 and the second reverse
gear wheel 36 are fixed onto the reverse gear idler shaft 38
coaxially such that the first reverse gear wheel 35 and the second
reverse gear wheel 36 rotates together with the reverse gear idler
shaft 38. The first reverse gear wheel 35 meshes with the fixed
wheel second gear 30. The second reverse gear wheel 36 meshes with
the reverse gear idler wheel 37.
[0062] The lower layshaft 50 is provided below the input shafts 20,
22. A plurality of components is mounted on the lower layshaft 50.
The components include gearwheels, coupling devices and bearings.
The components comprises, from right to the left, the lower pinion
51, a layshaft bearing 73, an idler second gear 61, a double-sided
coupling device 84, an idler fourth gear 63, a park-lock gearwheel
39, an idler third gear 62, a double-sided coupling device 83, an
idler first gear 60, and a layshaft bearing 73. The lower pinion 51
is fixed onto the lower layshaft 50 at its longitudinal axis. The
idler second gear 61, the idler fourth gear 63, the idler third
gear 62, and the idler first gear 60 are mounted on the lower
layshaft 50 by bearings separately such that these gearwheels
become idlers, being free to rotate around the lower layshaft 50.
In contrast, the park-lock gearwheel 39 is fixed onto the lower
layshaft 50 coaxially.
[0063] The double-sided coupling devices 84 can move along the
lower layshaft 50 such that it can engage either the idler second
gear 61 or the idler fourth gear 63 to the lower layshaft 50. The
double-sided coupling device 83 can also move along the lower
layshaft 50 such that it can engage either the idler first gear 60
or the idler third gear 62 to the lower layshaft 50. The idler
second gear 61 meshes with the fixed wheel second gear 30. The
idler fourth gear 63 meshes with the fixed wheel fourth gear 31.
The idler third gear 62 meshes with the fixed wheel third gear 25.
The idler first gear 60 meshes with the fixed wheel first gear
24.
[0064] There are two double-meshing features provided in the DCT 1.
A first double-meshing feature comprises that the fixed wheel
fourth gear 31 meshes with both the idler fourth gear 63 and the
idler sixth gear 65. A second double-meshing feature comprises that
the fixed wheel second gear 30 meshes with both the first reverse
gear wheel 35 and the idler second gear 61.
[0065] The park-lock gearwheel 39 comprises a park-lock on the
lower layshaft 50 that has a final drive pinion 51. The park-lock
is the park-lock gearwheel 39 which is provided with a ratchet
device, with a click device having a rack element, a pawl or
similar. The park-lock keeps the lower layshaft 50, the lower
pinion 51, the output gearwheel 12, and the output shaft 14 from
rotating, which stops a vehicle with the DCT 1 from running when
parked. Detailed structure of the park-lock is not shown in FIG.
2.
[0066] The DCT 1 with the park-lock is controlled by a gearshift
lever located in a driving compartment and movable by a vehicle
operator between positions corresponding to transmission gear
ranges such as Park, Reverse, Neutral, Drive, and Low. A linear
actuation cable is attached at its first end to the gearshift
lever, and movement of the gearshift lever alternatively pushes or
pulls on the cable to move a transmission mode select lever
attached to the other end of the cable. The mode select lever is
mechanically connected to a shift valve within a DCT housing, and
movement of the shift valve effects shifting between different
gears.
[0067] When the gearshift lever is placed in the Park position, two
related mechanical actuations take place within the DCT 1. First,
the mode select lever is moved to disengage the input shafts 20, 22
from an engine. Second, the park-lock pawl is moved into locking
engagement with the park-lock gearwheel 39 on the lower layshaft 50
to thereby lock the output shaft 14 against rotation. A linear
actuation cable that actuates the mode select lever moves the lock
pawl.
[0068] A distance 56 between the input shafts 20, 22 and the upper
layshaft 40 is measured from a common longitudinal axis of the
input shafts 20, 22 to a longitudinal axis of the upper layshaft
40. Similarly, a distance 58 between the input shafts 20, 22 and
the lower layshafts 50 is measured from the common longitudinal
axis of the input shafts 20, 22 to a longitudinal axis of the lower
layshaft 50.
[0069] The output shaft 14 is further provided further below the
lower layshaft 50. Two output shaft bearings 75 are installed at
two opposite ends of the output shaft 14 respectively for
supporting. The output gearwheel 12 is fixed onto the output shaft
14 coaxially in the middle. The output gearwheel 12 meshes with the
lower pinion 51 and the upper pinion 41.
[0070] In the present specification, the expressions "mesh" and
"comb" with respect to geared wheels or engaged gearwheels are
provided as synonyms. In a generic sense, a hollow shaft that is
disposed inside the hollow input shaft 22 can replace the solid
input shaft 20. The term "coupling device" is alternatively termed
as "shifting mechanism" or "synchronizer" for engaging or
disengaging gearwheels on its carrying shaft. The double-clutch
transmission (DCT) is alternatively termed as a double clutch, or a
dual clutch transmission (DCT).
[0071] The fixed wheel first gear 24 is also known as the first
fixed gearwheel 24. Similarly, the fixed wheel third gear 25 is
also known as the third fixed gearwheel 25. The fixed wheel fifth
gear 26 is also known as the fifth fixed gearwheel 26. The fixed
wheel seventh gear 27 is also known as the seventh fixed gearwheel
27. The fixed wheel second gear 30 is also known the second fixed
gearwheel 30. The fixed wheel fourth gear 31 is also known as the
fourth fixed gearwheel 31. The fixed wheel sixth gear 32 is also
known as the sixth fixed gearwheel 32.
[0072] Further, the second reverse gear idler wheel 35 is also
known as the second reverse idler gearwheel 35. The reverse gear
idler wheel 37 is also known as the reverse idler gearwheel 37. The
idler first gear 60 is also known as the first gear idler gearwheel
60. The idler second gear 61 is also known as the second gear idler
gearwheel 61. The idler third gear 62 is also known as the third
fixed gearwheel 62. The idler fourth gear 63 is also known as the
fourth gear idler gearwheel 63. The idler fifth gear 64 is also
known as the fifth gear idler gearwheel 64. The idler sixth gear 65
is also known as the sixth gear idler gearwheel 65. The idler
seventh gear 66 is also known as the seventh gear idler gearwheel
66.
[0073] The output gear wheel 12, the park-lock gearwheel 39, the
upper pinion 41, the lower pinion 51, and the reverse pinion 55 are
known as fixed gearwheels or gear wheels. In addition, the fixed
wheel first gear 24, the fixed wheel third gear 25, the fixed wheel
fifth gear 26, the fixed wheel seventh gear 27, the fixed wheel
second gear 30, the fixed wheel fourth gear 31, the fixed wheel
sixth gear 32 are also known as fixed gearwheels or gear
wheels.
[0074] The upper pinion 41, the lower pinion 51, and the reverse
pinion 55 are alternatively known called final drive pinions or
final drives. The park-lock on the park-lock gearwheel 39 can
alternatively be provided on any of the layshafts 38, 40, 50 that
has a final drive pinion. Any of the input shafts 20, 22 or
layshafts 38, 40, 50 can be supported by more than two
bearings.
[0075] In the drawings of the present application, dash lines
indicate either alternative positions of illustrated parts or
combing relationship between gearwheels.
[0076] The application provides the DCT 1 that permits gearshift
operations with less loss of driving torque. This is because the
gearshift operations can be achieved by selectively connecting one
of the two clutch discs 8, 10 of the DCT 1. Therefore, an
associated additional main drive clutch can be avoided. Selective
connections between the two clutch discs 8, 10 also enable the
realization of an automatic transmission that can be operated
without interruptions in propulsive power. The propulsive power
comprises momentum derived from the rotating gearwheels and shafts
of the DCT 1. Such a transmission is similar in design to a
mechanical manual transmission and it has correspondingly very low
friction losses. The DCT 1 further provides a parallel manual
transmission that can be used for transverse installation in a
front-wheel drive vehicle.
[0077] The DCT 1 according to the application can be connected
similar to a known manual transmission, such as a parallel manual
transmission. In the known manual transmission, a drive shaft for
the front axle of a vehicle extends outward from its DCT case, and
parallel to the output shaft 14 of the main DCT 1. The arrangement
of the known manual transmission provides little space left for
actuation of the manual transmission and clutch, and for an
optional electric motor. The optional electric motor can act as a
starter device for a combustion engine, as an energy recuperation
device for brake operation or as an additional drive means in
hybrid vehicles. Having such little space presents difficulties
that are solved or that at least alleviated by the application. The
application provides a DCT 1 that has two clutches for connecting
to an electrical motor and the manual transmission respectively in
a compact manner.
[0078] The application provides a compact structure of a parallel
transmission. The parallel transmission includes two input shafts
20, 22, each of which can be non-rotatably coupled to a shaft via
its own clutch that is powered by a drive engine of a vehicle. The
DCT 1 of the application further provides the output shaft 14 that
is parallel to the input shafts 20, 22.
[0079] The DCT 1 according to the application is particularly well
suited for transverse installation in front-wheel drive vehicles,
in which the front differential, for example, is positioned below
the pinions 41, 51. A short overall length of the power train for
transmitting torques can be achieved.
[0080] The application provides at least two relatively small
pinions 41, 51 on intermediately arranged layshafts 40, 50 that
comb with one relatively big output gearwheel 12. The output
gearwheel 12 in turn is fixed onto the output shaft 14. This
arrangement provides a compact and lightweight DCT 1.
[0081] The application further enables a design in which the output
gearwheel 12 is integrated into a transmission differential device
without providing an intermediate output shaft of the DCT 1. This
allows a very dense packaging situation for the DCT 1.
[0082] It is further not only of advantage to provide the even
gearwheels fixed onto one input shaft, but also fix the odd gears
onto another input shaft. This arrangement provides the
above-mentioned power-shift operation in a smooth and efficient
manner when gearshift is performed sequentially. This is because
the DCT 1 can alternatively engage one of the two clutch discs 8,
10 in the process of increasing or decreasing gear. For example,
the power-shift operation from the third gear to the fourth gear
causes the solid input shaft 20 and the hollow input shaft 22 being
engaged alternatively, which is energy efficient and fast.
[0083] Some idler gearwheels of the low gears, such as first,
second, third, or fourth gear, provided advantageously on the same
layshaft 50. In FIG. 2, the idler first gear 60, the idler second
gear 61, the idler third gear 62 and the idler fourth gear 63 are
installed on the same lower layshaft 40. In contrast, idler
gearwheels of high gears, such as fifth, sixth, or seventh gears,
provided on another layshaft. According to FIG. 2, the idler fifth
gear 64, the idler sixth gear 65, and the idler seventh gear 66 are
provided on the same upper layshaft 50. The upper layshaft 40 has
higher rotational speed with smaller diameter for lower torque
transmission, as compared to that of the lower layshaft 50. This
arrangement eliminates the need of providing multiple layshafts
with large size for carrying those heavily duty idler gearwheels
60, 61, 62, 63 of low gears, such as first, second, third, or
fourth gear, on many shafts respectively. These arrangements offer
the feasibility of making the DCT 1 lightweight and compact at less
cost.
[0084] The layshaft bearings 73 of the DCT 1 are next to the
pinions 41, 51. The layshaft bearings 73 offer strong support to
the pinions 41, 51 carrying layshafts 40, 50 for reducing unwanted
shaft deflection. Excessive shaft deflection can lower gear
transmission efficiency or cause gearwheels' early worn out. The
idler shaft bearings 74 next to the first reverse gear wheel 35 and
the second reverse gear wheel 36 also provide strong support to the
reverse gear idler shaft 38. In a like manner, the output shaft
bearings 75 at two opposite ends of the output shaft 14 offer
sturdy support to the output shaft 14.
[0085] In fact, it is also beneficial to provide the idler first
gear 60, the idler second gear 61, and the reverse gear idler wheel
37 close to the bearings 73, 74 for supporting. As shown in FIG. 2,
the three layshaft-bearings 73 are immediately adjacent to the
idler first gear 60, the idler second gear 61, and the reverse gear
idler wheel 37 respectively for giving strong support to the upper
layshaft 40 and the lower layshaft 50. The pinions 41, 51 and
especially these gearwheels of low gears, for example first and
second gears, undergo heavier load than those of the higher gears,
for example fifth, sixth, and seventh gears, because drive ratios
are higher for the lower gears and reverse gears. Therefore, a
carrying shaft of low gears, such as the lower layshaft 50, must
take up stronger driving torques and carry heavier gearwheels with
larger sizes. If those loads are taken up close to the supporting
bearings of the shafts, their load-carrying shafts' bending will be
reduced.
[0086] FIG. 2 illustrates the path of torque flow of a first gear
transmission ratio. In FIG. 2, an input torque of the first gear is
received from a crankshaft 2 of a combustion engine that is not
shown. According to FIG. 2, the solid input shaft 20 from the
double-clutch 6 of the DCT 1 receives the input torque of the first
gear. The torque of the first gear is transmitted from the solid
input shaft 20, via the fixed wheel first gear 24, via the idler
first gear 60, via the double-sided coupling device 83, via the
lower layshaft 50, via lower pinion 51, and via the output gear
wheel 12 to the output shaft 14. The double-sided coupling device
83 engages the idler first gear 60 to the lower layshaft 50 when
transmitting the torque of the first gear, which provides the first
gear of the DCT 1. The number of tooth engagements or engaged gear
pairs for the torque transfer of the first gear is two.
[0087] FIG. 3 illustrates the path of torque flow of a second gear
transmission ratio. In FIG. 3, an input torque of the second gear
is received from the crankshaft 2 of the combustion engine that is
not shown. According to FIG. 3, the hollow input shaft 20 from the
double-clutch 6 of the DCT 1 receives the input torque of the
second gear. The torque of the second gear is transmitted from the
hollow input shaft 22, via the fixed wheel second gear 30, via the
idler second gear 61, via the double-sided coupling device 84, via
the lower layshaft 50, via the lower pinion 51, and via the output
gearwheel 12 to the output shaft 14. The double-sided coupling
device 84 engages the idler second gear 61 to the lower layshaft 50
when transmitting the torque of the second gear, which provides the
second gear of the DCT 1. The number of tooth engagements or
engaged gear pairs for the torque transfer of the second gear is
two.
[0088] FIG. 4 illustrates the path of torque flow of a third gear
transmission ratio. In FIG. 4, an input torque of the third gear is
received from the crankshaft 2 of the combustion engine that is not
shown. According to FIG. 4, the solid input shaft 20 from the
double clutch of the DCT 1 receives the input torque of the third
gear. The torque of the third gear is transmitted from the solid
input shaft 20, via the fixed wheel third gear 25, via the idler
third gear 62, via the double-sided coupling device 83, via the
lower layshaft 50, via the lower pinion 51, and via the output gear
wheel 12 to the output shaft 14. The double-sided coupling device
83 engages the idler wheel third gear 62 to the lower layshaft 50
when transmitting the torque of the third gear, which provides the
third gear of the DCT 1. The number of tooth engagements or engaged
gear pairs for the torque transfer of the third gear is two.
[0089] FIG. 5 illustrates the path of torque flow of a fourth gear
transmission ratio. In FIG. 5, an input torque of the fourth gear
is received from the crankshaft 2 of the combustion engine that is
not shown. According to FIG. 5, the hollow input shaft 22 from the
double-clutch 6 of the DCT 1 receives the input torque of the
fourth gear. The torque of the fourth gear is transmitted from the
hollow input shaft 22, via the fixed wheel fourth gear 31, via the
idler fourth gear 63, via the double-sided coupling device 84, via
the lower layshaft 50, via the lower pinion 51, and via the output
gearwheel 12 to the output shaft 14. The double-sided coupling
device 84 engages the idler fourth gear 63 to the lower layshaft 50
when transmitting the torque of the fourth gear, which provides the
fourth gear of the DCT 1. The number of tooth engagements or
engaged gear pairs for the torque transfer of the fourth gear is
two.
[0090] FIG. 6 illustrates the path of torque flow of a fifth gear
transmission ratio. In FIG. 6, an input torque of the fifth gear is
received from the crankshaft 2 of a combustion engine that is not
shown. According to FIG. 6, the solid input shaft 20 from the
double-clutch 6 of the DCT 1 receives the input torque of the fifth
gear. The torque of the fifth gear is transmitted from the solid
input shaft 20, via the fixed wheel fifth gear 26, via the idler
fifth gear 64, via the double-sided coupling device 82, via the
upper layshaft 40, via the upper pinion 41, and via the output
gearwheel 12 to the output shaft 14. The double-sided coupling
device 82 engages the idler fifth gear 64 to the upper layshaft 40
when transmitting the torque of the fifth gear, which provides the
fifth gear of the DCT 1. The number of tooth engagements or engaged
gear pairs for the torque transfer of the fifth gear is two.
[0091] FIG. 7 illustrates the path of torque flow of a sixth gear
transmission ratio. In FIG. 7, an input torque of the sixth gear is
received from the crankshaft 2 of a combustion engine that is not
shown. According to FIG. 7, the hollow input shaft 22 from the
double-clutch 6 of the DCT 1 receives the input torque of the sixth
gear. The torque of the sixth gear is transmitted from the hollow
input shaft 22, via the fixed wheel sixth gear 32, via the idler
sixth gear 65, via the double-sided coupling device 81, via the
upper layshaft 40, via the upper pinion 41, and via the output gear
wheel 12 to the output shaft 14. The double-sided coupling device
81 engages the idler sixth gear 65 to the upper layshaft 40 when
transmitting the torque of the sixth gear, which provides the sixth
gear of the DCT 1. The number of tooth engagements or engaged gear
pairs for the torque transfer of the sixth gear is two.
[0092] FIG. 8 illustrates the path of torque flow of a seventh gear
transmission ratio. In FIG. 8, an input torque of the seventh gear
is received from the crankshaft 2 of a combustion engine that is
not shown. According to FIG. 8, the solid input shaft 20 from the
double-clutch 6 of the DCT 1 receives the input torque of the
seventh gear. The torque of the seventh gear is transmitted from
the solid input shaft 20, via the fixed wheel seventh gear 27, via
the idler seventh gear 66, via the double-sided coupling device 82,
via the upper layshaft 40, via the upper pinion 41, and via the
output gearwheel 12 to the output shaft 14. The double-sided
coupling device 82 engages the idler seventh gear 66 to the upper
layshaft 40 when transmitting the torque of the seventh gear, which
provides the seventh gear of the DCT 1. The number of tooth
engagements or engaged gear pairs for the torque transfer of the
seventh gear is two.
[0093] FIG. 9 illustrates the path of torque flow of a reverse gear
transmission ratio. In FIG. 9, an input torque of the reverse gear
is received from the crankshaft 2 of a combustion engine that is
not shown. According to FIG. 9, the hollow input shaft 22 from the
double-clutch 6 of the DCT 1 receives the input torque of the
reverse gear. The torque of the reverse gear is transmitted from
the hollow input shaft 22, via the fixed wheel second gear 30, via
the first reverse gear wheel 35, via the reverse gear idler shaft
38, via the second reverse gear wheel 36, and via the reverse gear
idler wheel 37. Then, the torque is transmitted via the
double-sided coupling device 81, via the upper layshaft 40, via the
upper pinion 41, and via the output gearwheel 12 to the output
shaft 14. The double-sided coupling device 81 engages the reverse
gear idler wheel 37 to the upper layshaft 40 when transmitting the
torque of the reverse gear ratio, which provides the reverse gear
of the DCT 1. The number of tooth engagements or engaged gear pairs
for the torque transfer of the reverse gear is three.
[0094] FIG. 10 illustrates an assembly 100 of a double-sided
coupling device 102 with its neighboring gearwheels 101, 103 for
engagement. The assembly 100 comprises a shaft 104 with the two
coaxially mounted idler gears 101, 103 on two bearings
respectively. The coupling device 102 is provided between the idler
gear 101 on the left and the idler gear 103 on the right. The
coupling device 102 is configured to move along the shaft 104 to
selectively engage any of the idler gears 101, 103 at one time. In
other words, the idler gears 101, 103 can alternatively be brought
into non-rotating engagement with the shaft 104 by the coupling
device 102. Symbols for showing the assembly 100 is provided at the
right hand side of FIG. 10.
[0095] FIG. 11 illustrates an assembly 110 of a single-sided
coupling device 112 with its neighboring gearwheel 113 for
engagement. The assembly 110 comprises a shaft 114 with the one
coaxially mounted idler gear 113 on a bearing. The coupling device
112 is provided next to the idler gear 113 on the left side. The
coupling device 112 is configured to move along the shaft 114 to
engage or disengage the idler gears 113. In other words, the idler
gear 113 can be brought into non-rotating engagement with the shaft
114 by the single-sided coupling device 112. Symbols for showing
the assembly 110 are provided at the right hand side of FIG.
11.
[0096] FIG. 12 illustrates an assembly 120 of an idler gearwheel
121 that is rotatably supported by a shaft 122 on a bearing 123.
The idler gearwheel 121 is coaxially mounted onto the shaft 122 via
the bearing 123. The bearing 123 enables the idler gearwheel 121 to
be freely rotated around the shaft 122. Symbols that represent the
assembly 120 are provided at the right hand side of the FIG.
12.
[0097] FIG. 13 illustrates an assembly 130 of a fixed gearwheel 132
that is supported on a shaft 131. The fixed gearwheel 132 is
coaxially mounted onto the shaft 131 such that the gearwheel 132 is
fixed to the shaft 131. The fixed gearwheel 132 and the shaft 131
are joined as one single body such that torque of the fixed
gearwheel 132 is transmitted to the shaft 131 directly, and vice
versa.
[0098] A number of fixed gearwheels are rigidly connected to the
input shafts 20, 22 and other shafts 14, 38, 40, 50 in a manner
that is similar to the assembly 130. A symbol as used in the
previous figures for such a fixed gearwheel is provided on the left
side in FIG. 13. The more commonly used symbol for such a fixed
gearwheel is provided on the right side in FIG. 13.
[0099] FIG. 14 illustrates a cross-section through a detail of a
crankshaft 2 of an internal combustion engine according to the
embodiment of the DCT 1. According to FIG. 14, the crankshaft 2 of
the internal combustion engine, which is not shown here, is
non-rotatably connected to a housing 4 of a double clutch 6. The
double clutch 6 includes an inner clutch disc 8 and an outer clutch
disc 10, which can be brought into non-rotating engagement with the
housing 4 via control elements that are not illustrated here. The
solid input shaft 20 can be non-rotatably connected to the inner
clutch disc 8, and extends all the way through the hollow shaft 22.
Similarly, the hollow input shaft 22 can be non-rotatably connected
to the outer clutch disc 10. The inner clutch disc 8 is also known
as the inner clutch, whilst the outer clutch disc 10 is also known
as the outer clutch. The input shafts 20, 22 comprise ends 5 that
are connected to the two clutch discs 8, 10. These ends are also
termed as clutch disc ends 5 of the input shafts.
[0100] An outer diameter around the inner clutch disc 8 is larger
than an outer diameter around the outer clutch disc 10.
Correspondingly, an outer diameter of the inner clutch disc 8 is
larger than an outer diameter of the outer clutch disc 10.
[0101] The above-mentioned nine torque flow paths not only provide
viable solutions to generate nine gears of the DCT 1, but also
offer possibilities of switching from one gear to the another
efficiently. The gear switching can be achieved by switching
between the two input shafts, between gearwheels of a double
meshing feature, or in combination of both.
[0102] For example, the DCT 1 can provide odd gears (i.e. 1st, 3rd,
5th & 7th gears) by driving the gearwheels of the DCT 1 using
the solid input shaft 20. The DCT 1 also can provide even gears
(i.e. 2nd, 4th & 6th gears) by driving the gearwheels of
the
[0103] DCT 1 using the hollow input shaft 22. Gear switching
between the odd and the even can simply be obtained by alternating
between the two input shafts 20, 22.
[0104] One double meshing feature provides efficient and fast gear
switching between gears of two driven gearwheels that comb with a
shared driving gearwheel. For example, the DCT 1 provides the
convenience of selecting the fourth gear or the sixth gear without
stopping their shared driving gearwheel, namely the fixed wheel
fourth gear 31. The selection can be achieved by engaging either
the driven idler fourth gear 63 or the driven idler sixth gear
65.
[0105] The double-meshing feature of the fixed wheel fourth gear 31
reduces the number of driving gearwheels, which is commonly engaged
by the driven gearwheels idler fourth gear 63 and the driven
gearwheel idler sixth gear 65. For example, the fixed wheel fourth
gear 31 and the fixed wheel sixth gear 32 as driving gear wheels
become one single gearwheel that is shared by the idler fourth gear
63 and the idler sixth gear 65. As a result, the number of
gearwheels on the hollow input shaft 22 has been reduced by one
gearwheel and less space is required on the hollow input shaft 22
so that the DCT 1 can be made cheaper and lighter.
[0106] The park-lock gearwheel 39 comprises a park-lock on the
lower layshaft 50 that carries a final drive pinion 51. The
park-lock is a wheel which is provided with a ratchet device, with
a click device having a rack element, a claw or similar. The
park-lock keeps the lower layshaft 50, the lower pinion 51, the
output gear wheel 12, and the output shaft 14 from rotating, which
stops a vehicle with the DCT 1 from running when parked. Detailed
structure of the park-lock is not shown.
[0107] In providing gear meshing or combing for torque
transmission, less number of gear tooth engagement, that is gear
engagement, is preferred. The less number of gear tooth engagement
provides lower noise and more efficient torque transmission.
Examples of the less gear tooth engagement are provided in FIGS.
2-9.
[0108] The DCT 1 drives the gearwheel groups of the first gear and
the reverse gear by different input shafts 20, 22. A vehicle with
the DCT 1 can move between a slow forward mode and a slow backward
mode by engaging and disengaging the respective clutch discs 8, 10,
which are connected to the two input shafts 20, 22 respectively.
The DCT 1 enables the vehicle to move back and forth quickly with
little loss of the transmission power or gearwheels momentum. This
scheme helps in many situations in which a wheel of the vehicle is
stuck in a hostile environment such as a snow hole or a mud hole.
The vehicle can then be swayed free just by switching between the
two clutch discs 8, 10.
[0109] FIGS. 15-16 illustrate a further embodiment of the
application. The embodiment includes parts that are similar to the
parts of previously described embodiment. The similar parts are
labeled with the same or similar part reference number.
Descriptions related to the similar parts are hereby incorporated
by reference.
[0110] FIG. 15 shows a front view of the gearbox of the
application. A relatively big output gearwheel 12 on an output
shaft 14 meshes with a lower pinion 51, which is provided on a
lower layshaft 50. The output gearwheel 12 further meshes with an
upper pinion 41, which is provided on an upper layshaft 40. A
reverse gear idler shaft 38, a solid input shaft 20, and a hollow
output shaft 22 are provided in parallel with the layshafts 40, 50.
In some variants of the application, at least one a further
layshaft with a further pinion can be provided but this is not
shown here. Such a further pinion would then also mesh or comb with
the output gearwheel 12.
[0111] FIG. 15 further comprises a cutting plane A-A for
illustrating the cross-section through the gearbox, which is shown
in FIG. 16. For an embodiment, which has more than two layshafts or
an additional idler shaft, a cutting plane, which leads through all
shafts, is applied similarly. One of the goals of FIG. 16 is to
illustrate further the structure and the torque flows through the
embodiment of the gearbox.
[0112] FIG. 16 illustrates a simplified cross-section through the
double clutch transmission gearbox 1 of FIG. 15. It illustrates
structure and various torque flows for the several gears of the
double clutch transmission gearbox 1.
[0113] The double clutch transmission gearbox 1 comprises the
following shafts, from top to bottom, the output shaft 14, the
upper layshaft 40, the hollow shaft 22, the solid input shaft 20,
the lower layshaft 50, and the reverse gear idler shaft 38.
[0114] The above-mentioned shafts are provided parallel to each
other at predetermined mutual distances inside the gearbox 1. The
hollow shaft 22 is arranged concentrically around the solid shaft
20. The solid input shaft 20 protrudes outside the hollow input
shaft 22 at both ends.
[0115] The solid input shaft 20 comprises, from the right end to
the left end, a solid shaft bearing 71, a hollow shaft bearing 72,
a fixed wheel third gear 25, a fixed wheel fifth gear 26, a fixed
wheel first gear 24, a fixed wheel seventh gear 27, and a solid
shaft bearing 71. The hollow shaft bearing 72 serves also as solid
shaft bearing 71.
[0116] The hollow input shaft 22 comprises, from the right end to
the left end, a hollow shaft bearing 72, a fixed wheel second gear
30, a fixed wheel fourth gear 31, which also serves as a fixed
wheel sixth gear 32, and the hollow shaft bearing 72, which also
serves as the solid shaft bearing 71.
[0117] The upper layshaft 40 comprises, from the right end to the
left end, the upper pinion 41, a layshaft bearing 73, an idler
second gear 61, a double-sided coupling device 80, an idler fifth
gear 64, an idler third gear 62, a double-sided coupling device 81,
an idler first gear 60, and a layshaft bearing 73. The idler second
gear 61 meshes with the fixed wheel second gear 30. The idler fifth
gear 64 meshes with the fixed wheel fourth gear 31. The idler third
gear 62 meshes with the fixed wheel third gear 25. The idler first
gear 60 meshes with the fixed wheel first gear 24. The double-sided
coupling device 80 is configured to move the along the upper
layshaft 40 for engaging either attached the idler second gear 61
or the idler fifth gear 64 to the upper layshaft 40. The
double-sided coupling device 81 is also configured to move along
the upper layshaft 40 for engaging either the idler third gear 62
or the idler first gear 60 to the upper layshaft 40.
[0118] The lower layshaft 50 comprises, from the right end to the
left end, the lower pinion 51, a layshaft bearing 73, an reverse
gear idler wheel 37, a double-sided coupling device 83, an idler
sixth gear 65, a park-lock gearwheel 39, an idler fifth gear 64, a
double-sided coupling device 82, an idler seventh gear 66, and a
layshaft bearing 73. The idler sixth gear 65 meshes with the fixed
wheel sixth gear 32. The idler fifth gear 64 meshes with the fixed
wheel fifth gear 26. The idler seventh gear 66 meshes with the
fixed wheel seventh gear 27. The double-sided coupling device 83 is
configured to move along the lower layshaft 50 for engaging either
the reverse gear idler wheel 37 or the idler sixth gear 65 to the
lower layshaft 50. The double-sided coupling device 82 is also
configured to move along the lower layshaft 50 for engaging either
the idler fifth gear 64 or the idler seventh gear 66 to the lower
layshaft 50.
[0119] The reverse gear idler shaft 38 comprises, from the right
end to the left end, an idler shaft bearing 74, a first reverse
gear wheel 35, a second reverse gear wheel 36, and an idler shaft
bearing 74. The first reverse gear wheel 35 meshes with the fixed
wheel second gear 30. The second reverse gear wheel 36 meshes with
the reverse gear idler wheel 37.
[0120] FIG. 16 also shows a clutch housing 4 that encloses
gearwheels of the double-clutch transmission 1. The clutch housing
4 comprises several walls 3, 6 that are closely neighboring to the
gearwheels of the double-clutch transmission 1. In particular, a
sidewall 6 of the clutch housing 4 is located near the first gear
idler gearwheel 60 at an end of the upper layshaft 40. The first
gear idler gearwheel 60 resides on the end that is opposite to an
end of on the upper layshaft 40 fixed with the upper pinion 41.
[0121] In FIG. 16, the idler seventh gear 66 is mounted on the left
end of the lower layshaft 50, which is opposite to the end that
carries lower pinion 51. The idler seventh gear 66 has the smallest
diameter as compared to that of the idler of other gears 60, 61,
62, 63, 64, 65. Putting the idler seventh gear 66 at the end
enables the sidewall 3 to be closer to the lower layshaft 50, as
compared to the situation of putting the idler of other gears 60,
61, 62, 63, 64, 65 at this end.
[0122] Therefore, in order to make the double-clutch transmission 1
to be more compact, it is beneficial to mount idlers of different
gears on a layshaft from a low gear to a high gear sequentially,
starting from an end of the layshaft with a pinion to a remote end
of the layshaft. Furthermore, it is further advantageous to mount
fixed gearwheels of different gears an input shaft 20, 22 from a
high gear to a low gear sequentially, starting from an end of the
input shaft 20, 22 for connecting to a crankshaft 2. A fixed
gearwheel of a high gear on the input shaft 20, 22 is larger than
that of a low gear.
[0123] Torque flow of the first gear according to FIG. 16 starts
from the solid input shaft 22, via the fixed wheel first gear 24,
via the idler first gear 60, via the double-sided coupling device
81, via the upper layshaft 40, via the upper pinion 41, via the
output gear wheel 12, to the output shaft 14.
[0124] Torque flow of the second gear according to FIG. 16 starts
from the hollow input shaft 22, via the fixed wheel second gear 30,
via the idler second gear 61, via the double-sided coupling device
80, via the upper layshaft 40, via the upper pinion 41, via the
output gear wheel 12, to the output shaft 14.
[0125] Torque flow of the third gear according to FIG. 16 starts
from the solid input shaft 20, via the fixed wheel third gear 25,
via the idler third gear 62, via the double-sided coupling device
81, via the upper layshaft 40, via the upper pinion 41, via the
output gear wheel 12, to the output shaft 14.
[0126] Torque flow of the fourth gear according to FIG. 16 starts
from the hollow input shaft 22, via the fixed wheel fourth gear 31,
via the idler fourth gear 63, via the double-sided coupling device
80, via the upper layshaft 40, via the upper pinion 41, via the
output gear wheel 12, to the output shaft 14.
[0127] Torque flow of the fifth gear according to FIG. 16 starts
from the solid input shaft 20, via the fixed wheel fifth gear 26,
via the idler fifth gear 64, via the double-sided coupling device
82, via the lower layshaft 50, via the lower pinion 51, via the
output gear wheel 12, to the output shaft 14.
[0128] Torque flow of the sixth gear according to FIG. 16 starts
from the hollow input shaft 22, via the fixed wheel sixth gear 32,
via the idler sixth gear 65, via the double-sided coupling device
83, via the lower layshaft 50, via the lower pinion 51, via the
output gear wheel 12, to the output shaft 14.
[0129] Torque flow of the seventh gear according to FIG. 16 starts
from the solid input shaft 20, via the fixed wheel seventh gear 27,
via the idler seventh gear 66, via the double-sided coupling device
82, via the lower layshaft 50, via the lower pinion 51, via the
output gear wheel 12, to the output shaft 14.
[0130] Torque flow of the reverse gear according to FIG. 16 starts
from the hollow input shaft 22, via the fixed wheel second gear 30,
via the first reverse gear wheel 35, via the reverse gear idler
shaft 38, via the second reverse gear wheel 36, and via the reverse
gear idler wheel 37. The torque is then transmitted via the
double-sided coupling device 83, via the lower layshaft 50, via the
lower pinion 51, and via the output gear wheel 12 to the output
shaft 14.
[0131] FIGS. 17-18 illustrate a further embodiment of the
application. The embodiment includes parts that are similar to the
parts of previously described embodiment. The similar parts are
labeled with the same or similar part reference number.
Descriptions related to the similar parts are hereby incorporated
by reference.
[0132] FIGS. 17-18 illustrate a further embodiment of the
application. The embodiment includes parts that are similar to the
parts of previously described embodiment. The similar parts are
labeled with the same or similar part reference number.
Descriptions related to the similar parts are hereby incorporated
by reference.
[0133] FIG. 17 shows a front view of the gearbox of the
application. A relatively big output gearwheel 12 on an output
shaft 14 meshes with a lower pinion 51, which is provided on a
lower layshaft 50. The output gearwheel 12 further meshes with an
upper pinion 41, which is provided on an upper layshaft 40. A
reverse gear idler shaft 38, a solid input shaft 20, and a hollow
output shaft 22 are provided in parallel with the layshafts 40, 50.
In some variants of the application, at least one a further
layshaft with a further pinion can be provided but this is not
shown here. Such a further pinion would then also mesh or comb with
the output gearwheel 12.
[0134] FIG. 17 further comprises a cutting plane A-A for
illustrating the cross-section through the gearbox, which is shown
in FIG. 18. For an embodiment, which has more than two layshafts or
an additional idler shaft, a cutting plane, which leads through all
shafts, is applied similarly. One of the goals of FIG. 18 is to
illustrate further the structure and the torque flows through the
embodiment of the gearbox.
[0135] FIG. 18 illustrates a simplified cross-section through the
double clutch transmission gearbox 1 of FIG. 17. It illustrates
structure and various torque flows for the several gears of the
double clutch transmission gearbox 1.
[0136] The double clutch transmission gearbox 1 comprises the
following shafts, from top to bottom, the output shaft 14, the
upper layshaft 40, the hollow shaft 22, the solid input shaft 20,
the lower layshaft 50 and the reverse gear idler shaft 38.
[0137] The above-mentioned shafts are provided parallel to each
other at predetermined mutual distances inside the gearbox 1. The
hollow shaft 22 is arranged concentrically around the solid shaft
20. The solid input shaft 20 protrudes outside the hollow input
shaft 22 at both ends.
[0138] The solid input shaft 20 comprises, from the right end to
the left end, a solid shaft bearing 71, a hollow shaft bearing 72,
which serves also as solid shaft bearing 71, a fixed wheel third
gear 25, a fixed wheel fifth gear 26, a fixed wheel seventh gear
27, a fixed wheel first gear 24, and a solid shaft bearing 71.
[0139] The hollow input shaft 22 comprises, from the right end to
the left end, a hollow shaft bearing 72, a fixed wheel second gear
30, a fixed wheel fourth gear 31, which also serves as a fixed
wheel sixth gear 32, and the hollow shaft bearing 72, which also
serves as the solid shaft bearing 71.
[0140] The upper layshaft 40 comprises, from the right end to the
left end, the upper pinion 41, a layshaft bearing 73, an idler
second gear 61, a double-sided coupling device 80, an idler fifth
gear 64, an idler third gear 62, a double-sided coupling device 81,
an idler first gear 60, and a layshaft bearing 73. The idler second
gear 61 meshes with the fixed wheel second gear 30. The idler fifth
gear 64 meshes with the fixed wheel fourth gear 31. The idler third
gear 62 meshes with the fixed wheel third gear 25. The idler first
gear 60 meshes with the fixed wheel first gear 24. The double-sided
coupling device 80 is configured to move the along the upper
layshaft 40 for engaging either attached the idler second gear 61
or the idler fifth gear 64 to the upper layshaft 40. The
double-sided coupling device 81 is also configured to move along
the upper layshaft 40 for engaging either the idler third gear 62
or the idler first gear 60 to the upper layshaft 40.
[0141] The lower layshaft 50 comprises, from the right end to the
left end, the lower pinion 51, a layshaft bearing 73, an reverse
gear idler wheel 37, a double-sided coupling device 83, an idler
sixth gear 65, a park-lock gearwheel 39, an idler fifth gear 64, a
double-sided coupling device 82, an idler seventh gear 66, and a
layshaft bearing 73. The idler sixth gear 65 meshes with the fixed
wheel sixth gear 32. The idler fifth gear 64 meshes with the fixed
wheel fifth gear 26. The idler seventh gear 66 meshes with the
fixed wheel seventh gear 27. The double-sided coupling device 83 is
configured to move along the lower layshaft 50 for engaging either
the reverse gear idler wheel 37 or the idler sixth gear 65 to the
lower layshaft 50. The double-sided coupling device 82 is also
configured to move along the lower layshaft 50 for engaging either
the idler fifth gear 64 or the idler seventh gear 66 to the lower
layshaft 50.
[0142] The reverse gear idler shaft 38 comprises, from the right
end to the left end, an idler shaft bearing 74, a first reverse
gear wheel 35, a second reverse gear wheel 36, and an idler shaft
bearing 74. The first reverse gear wheel 35 meshes with the fixed
wheel second gear 30. The second reverse gear wheel 36 meshes with
the reverse gear idler wheel 37.
[0143] FIG. 18 also shows a clutch housing 4 that encloses
gearwheels of the double-clutch transmission 1. The clutch housing
4 comprises several walls 3, 7 that are closely neighboring to the
gearwheels of the double-clutch transmission 1. In particular, a
sidewall 7 of the clutch housing 4 is located near the first gear
idler gearwheel 60 at an end of the upper layshaft 40. The first
gear idler gearwheel 60 resides on the end that is opposite to an
end of on the upper layshaft 40 fixed with the upper pinion 41.
[0144] Compared to the clutch housing 4 of FIG. 16, the sidewall 6
of FIG. 16 is closer to the upper layshaft 40 than the sidewall 7
of FIG. 18. This is because the fixed wheel first gear 24 is at a
left side of the fixed wheel seventh gear 27. The largest idler of
seven gears 60 forces the sidewall 7 to be further away from the
upper layshaft 40. In short, the clutch housing 4 of FIG. 16 is
more compact than that of the FIG. 18.
[0145] Torque flow paths of seven forward gears and one reverse
gear of the present embodiment in FIGS. 17-18 are similar to that
of the FIGS. 15-16.
[0146] Although the above description contains much specificity,
these should not be construed as limiting the scope of the
embodiments but merely providing illustration of the foreseeable
embodiments. Especially the above stated advantages of the
embodiments should not be construed as limiting the scope of the
embodiments but merely to explain possible achievements if the
described embodiments are put into practice. Thus, the scope of the
embodiments should be determined by the claims, rather than by the
examples given.
[0147] While at least one exemplary embodiment has been presented
in the foregoing summary and detailed description, it should be
appreciated that a vast number of variations exist. It should also
be appreciated that the exemplary embodiment or exemplary
embodiments are only examples, and are not intended to limit the
scope, applicability, or configuration in any way. Rather, the
foregoing summary and detailed description will provide those
skilled in the art with a convenient road map for implementing an
exemplary embodiment of the invention, it being understood that
various changes may be made in the function and arrangement of
elements described in an exemplary embodiment without departing
from the scope as set forth in the appended claims and their legal
equivalents.
* * * * *