Indian Patents. 264165:MULTI-SPEED TRANSMISSION

Title of Invention	MULTI-SPEED TRANSMISSION
Abstract	The invention relates to a transmission is provided having an input member (12), an output member (14), four planetary gear sets (16,18,20,22), a plurality of coupling members (32,34,36,38) and a plurality of torque transmitting devices (80,82,84,86,90,92). Each of the planetary gear sets includes first, second and third members. The torque transmitting devices may include clutches and brakes.

Full Text	MULTI-SPEED TRANSMISSION CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Application No. 60/900,613 filed on February 8. 2007. The disclosure of the above application is incorporated herein by reference. TECHNICAL FIELD The invention relates generally to a multiple speed transmission having a plurality of planetary gear sets and a plurality of torque transmitting devices and more particularly to a transmission having nine or more speeds, four planetary gear sets and a plurality oflorque transmitting devices. BACKGROUND The statements in this section merely provide background information related to the present disclosure and may or may not constitute prior art. A typical multiple speed transmission uses a combination of friction clutches, planetary gear arrangements and fixed interconnections to achieve a plurality of gear ratios. The number and physical arrangement of the planetary gear sets, generally, are dictated by packaging, cost and desired speed ratios. While current transmissions achieve their intended purpose, the need for new and improved transmission configurations which exhibit improved performance, especially from the standpoints of efficiency, responsiveness and smoothness and improved packaging, primarily reduced • size and weight, is essentially constant. Accordingly, there is a need for an improved, cost-effective, compact multiple speed transmission. SUMMARY A transmission is provided having an input member, an output member, four planetary gear sets, a plurality of coupling members and a plurality of torque transmitting devices. Bach of the planetary gear sets includes first, second and third members. The torque transmitting devices may include clutches and brakes. One embodiment of the present invention includes an input member, an output member,, first, second, third and fourth planetary gear sets each having first, second and third members, a first interconnecting member continuously interconnecting the third member of the first planetary gear set with the first member of the second planetary gear set. a second interconnecting member continuously- interconnecting the third member of the second planetary gear set with the second member of the third planetary gear set. a third interconnecting member continuously interconnecting the third member of the third planetary gear set with the second member of the fourth planetary gear set, and a'fourth interconnecting member continuously interconnecting the first member of the third planetary gear set with the first member of the fourth planetary gear set. Six torque transmitting mechanisms are selectively engageable to interconnect one of the first,, second, and third members with another of the first, second, third members, and a stationary element. The torque transmitting mechanisms are selectively engageable in combinations of at least three to establish at least nine forward speed ratios and at least one reverse speed ratio between the input member and the output member. In one aspect of the present invention, a first of the six torque transmitting mechanisms is selectively engageable to interconnect the second member of the first planetary gear set with the second member of the second planetary gear set. In another aspect of the present invention, a second of the six torque transmitting mechanisms is selectively engageable to interconnect the second member of the second planetary gear set with the third member of the fourth planetary gear set. In yet another aspect of the present invention, a third of the six torque transmitting mechanisms is selectively engageable to interconnect at least one of the input member and the second member of the first planetary gear set with at least one of the first member of the third planetary gear set and the first member of the fourth planetary gear set. In yet another aspect of the present invention, a fourth of the six torque transmitting mechanisms is selectively engageable to interconnect at least one of the third member of the first planetary gear set and the first member of the second planetary gear set with at least one of the first member of the third planetary gear set and the first member of the fourth planetary gear set. In yet another aspect of the present .invention, a fifth of the six torque transmitting mechanisms is selectively engageable to interconnect the first member of the first planetary gear set with the stationary element. In ycl another aspect of the present invention, a sixth of the six torque transmitting mechanisms is selectively engagcable to interconnect the third member of the fourth planetary gear set with the stationary element. In yet another aspect of the present invention, the first members arc sun gears, the second members arc carrier members, and the third members are ring gears. 'n ycl another aspect of the present invention, the input member is continuously interconnected with the second member of the first planetary gear set and wherein .the output member is continuously interconnected with the second member of the fourth planetary gear set. In ycl another aspect of the present invention, two of the lorquc'.transmitting mechanisms are brakes and four of the torque transmitting mechanisms arc clutches. In yet another aspect of the present invention, the stationary element is a transmission housing. Another embodiment of the transmission includes an input member, an output member, first, second, third and fourth planetary gear sets each having a sun gear, a carrier, member, and a ring gear, wherein the input member is continuously interconnected with the carrier member of the first planetary gear set and wherein the output member is continuously interconnected with the carrier member of the fourth ■ planetary gear set, a first interconnecting member continuously interconnecting the ring gear of the first planetary gear set with the sun gear of the second planetary gear set. a second interconnecting member continuously interconnecting the ring gear of the second planetary gear set with the carrier member of the third planetary gear set. a third interconnecting member continuously interconnecting the ring gear of the third planetary gear set with Ihc carrier member of the fourth planetary gear set, and a fourth interconnecting member continuously interconnecting the sun gear of the third planetary gear set with the sun gear of the fourth planetary gear set. A first torque transmitting mechanism is selectively cngageablc to interconnect the carrier member of the first planetary gear set with the carrier member of the second planetary gear set. a second torque transmitting mechanism is selectively engageablc to interconnect the carrier member of the second planetary gear set with the ring gear of the fourth planetary gear set. a third torque transmitting mechanism is selectively cngageable to interconnect at least one of the input member and the carrier member of the first planetary gear set with at least one of the sun gear of the third planetary gear set and the sun gear of the fourth planetary gear set, a fourth torque transmitting mechanism is selectively engageablc to interconnect at least one of the ring gear of the first planetary gear set and the sun gear of the second planetary gear set with at least one of the sun gear of the third planetary gear set and the sun gear of the fourth planetary gear set, a fifth torque transmitting mechanism is selectively engageablc to interconnect the sun gear of the llrst planetary gear set with a stationary element, and a sixth torque transmitting mechanism is selectively engageablc to interconnect the ring gear of the fourth planetary gear set with the stationary element. The torque transmitting mechanisms are selectively cngageable in combinations of at least three to establish at least nine forward speed ratios and at least one reverse speed ratio between the input member and the output member. The above features and advantages and other features and advantages of the present invention are readily apparent from the following detailed description of the best modes for carrying out the-invention when taken in connection with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS The drawings described herein are for illustration purposes only and arc not intended to limit the scope of the present disclosure in any way. FIG. 1 is a lever diagram of an embodiment of a multiple speed transmission according to the present invention; FIG. 2 is a diagrammatic view of an embodiment of a multiple speed transmission according to the present invention; FIG. 3 is a truth table presenting the state of engagement of the various torque transmitting elements in each oflhc available forward and reverse speeds or gear ratios of the transmission illustrated in FIGS. 1 and 2: and FIG. 4 is an alternate truth table presenting the slate of engagement of the various torque transmitting elements in each of the available forward and reverse speeds or gear ratios of the transmission illustrated in FIGS. 1 and 2. DESCRIPTION At the outset, it should be appreciated that the automatic transmission of the present invention has an arrangement of permanent mechanical connections between the elements of the four planetary gear sets in common. These mechanical connections generically link or relate transmission embodiments. A first component or element of a first planetary gear set is permanently coupled to a first component or element of a second planetary gear set. A third component or element of the second planetary gear set is permanently coupled to a second component or element of a third planetary gear set. A first component or element of the third planetary gear set is permanently coupled to a first component or element of a fourth planetary gear set. Finally, a third component or element of the third planetary gear set is permanently coupled to a second component or element of the fourth planetary gear set. Referring now to FIG. 1, an embodiment of a multiple speed transmission 10 is illustrated in a lever diagram format. A lever diagram is a schematic representation of the components of a mechanical device such as an automatic transmission. Each individual lever represents a planetary gear set wherein the three basic mechanical components-of the planetary gear arc each represented by a node. Therefore, a single lever contains three nodes: one for the sun gear, one for the planet gear carrier, and one for the ring gear. The relative length between the nodes of each lever can be used to represent the ring-to-sun ratio of each respective gear set. These lever ratios, in turn, arc used to vary the gear ratios of the transmission in order to achieve an appropriate ratios and ratio progression. Mechanical couplings or interconnections between the nodes of the various planetary gear sets arc illustrated by thin, horizontal lines and torque transmitting devices such as clutches and brakes are presented as interleaved fingers. If the device is a brake, one set of the fingers is grounded. Further explanation of the format, purpose and use of lever diagrams can be found in SAE Paper 810102. "The Lever Analogy: A New Tool in Transmission Analysis" by Ben ford and Leising which is hereby fully incorporated by reference. The transmission 10 includes an input shaft or member 12, an output shaft or member 14, a first planetary gear set 16 having three nodes: a first node 24, a second node 26 and a third node 28: a second planetary gear set 18 having three nodes: a first node 42, a second node 44 and a third node 46, a third planetary gear set 20 having three nodes: a first node 52, a second node 54 and a third node 56, and a fourth planetary gear set 22 having three nodes: a first node 72. a second node 74 and a third node 76. The input member 12 is coupled to the third node 28 of the first planetary gear set 16. The output 14 is coupled to the third node 76 of the fourth planetary gear set 22. The second node 26 of the first planetary gear set 16 is coupled to the first node 42 of the second planetary gear set 18. The second node 44 of the second planetary gear set 18 is coupled to the third node 56 of the third planetary gear set 20. The first node 52 of the third planetary gear set 20 is coupled to the first node 72 of the fourth planetary gear set 22. The second node 54 of the third planetary gear set 20 is coupled to the third node 76 of the fourth planetary gear set 22. A first clutch 80 selectively connects the third node 28 of the first planetary gear set 16 to the third node 46 of the second planetary gear set 18. A second clutch 82 selectively connects the third node 46 of the second planetary gear set 18 to the second node 74 of the fourth planetary gear set 22. A third clutch 84 selectively connects the input member 12 to the first node 52 of the third planetary gear set 20. A fourth clutch 86 selectively connects the first node 42 of the second planetary gear set 18 to the first node 52 of the third planetary gear set 20. A first brake 90 selectively connects the first node 24 of the first planetary gear set 16 to a ground, stationary element or a transmission housing 100. A second brake 92 selectively connects the second node 74 of the fourth planetary gear set 22 to a ground, stationary element, or the transmission housing 100. Referring now to FIG. 2, ajstick diagram presents a schematic layout of the embodiment of the multiple speed transmission 10 according to the present invention. In FIG. 2. the numbering from the lever diagram of FIG. 1 is carried over. The clutches, brakes and couplings arc correspondingly presented whereas the nodes of the planetary gear sets now appear as components of planetary gear sets such as sun gears, ring gears. planet gears and planet gear carriers. For example, the first planetary gear set 16 includes a sun gear member 24. a ring gear member 26 and a carrier member 28 that rotatabIy supports a set of pinion gears 30 (only one shown). Bach of the pinion gears 30 arc configured to intermesh with both sun gear member 24 and ring gear member 26. Sun gear member 24 is connected for common rotation with a first interconnecting shaft or member 32. Ring gear member 26 is connected for common rotation with a second interconnecting shaft or member 34. Carrier member 28 is connected for common rotation with a third interconnecting shall or member 36 and with input shaft 12. The second planetary gear set, 18 includes a sun gear member 42. a ring gear member 44 and a carrier member 46 that roialably supports a set of pinion gears 48. Each of the opinion gears 48 are configured to intermesh with both sun gear member 42 and ring gear member 44. Sun gear member 42 is connected for common rotation with a fourth interconnecting shaft or member 38. Ring gear member 44 is connected for common rotation with a fifth interconnecting shaft or member 50. Carrier member 46 is connected for common rotation with a sixth interconnecting shaft or member 60. The third planetary gear set 20 includes a sun gear member 52, a ring gear member 54 and a carrier member 56 that rotalably supports a set of pinion gears 58. Each of the pinion gears 58 are configured to intermesh with both sun gear member 52 and ring gear member 54. Sun gear member 52 is connected for common rotation with a seventh interconnecting shaft or member 62. Ring gear member 54 is connected for common rotation with an eighth interconnecting shaft or member 64. Carrier member 56 is connected for common rotation with fifth interconnecting member 50. The fourth planetary gear set 22 includes a sun gear member 72, a ring gear member 74 and a carrier member 76 chat rotatably supports a set of pinion gears 78. Bach of the pinion gears 78 are configured to intermesh with both sun gear member 72 and ring gear member 74. Sun gear member 72 is connected for common rotation with seventh interconnecting member 62. Ring gear member 74 is connected for common rotation with a ninth interconnecting shaft or member 66. Carrier member 76 is connected for common rotation with eighth interconnecting member 64 and with output shaft 14. The input shaft 12 is continuously connected to an engine (not shown) or to a turbine of a torque converter (not shown). The output shaft 14 is continuously connected with the final drive unit (not shown). The transmission 10 includes a variety of torque-transmitting mechanisms or devices including a first clutch 80, a second clutch 82, a third clutch 84, a fourth clutch 86, a first brake 90 and a second brake 92. Firsi clutch 80 is selectively engagablc to connect third interconnecting member 36 to sixth interconnecting member 60. Second clutch 82 is selectively engagablc to connect sixth interconnecting member 60 to ninth interconnecting member 66. Third clutch 84 is selectively cngagablc to connect input shaft 12 to seventh interconnecting member 62. Fourth clutch 86 is selectively cngagablc to connect second and fourth interconnecting members 34, 38 to seventh interconnecting member 62. First brake 90 is selectively engagablc to connect first interconnecting member 32 to transmission housing 100 to restrict rotation of first interconnecting member 32 and sun gear 24 relative to housing 100. Second brake 92 is selectively cngagablc to connect ninth interconnecting member 66 to housing 100 to restrict rotation of ninth interconnecting member 66 and ring gear 74 relative to housing 100. Referring now to FIGS. 2 and 3, the operation of the embodiment of the multiple speed transmission 10 will be described. It will be appreciated that the transmission 10 is capable of transmitting torque from the input shaft or member 12 to the output shaft or member 14 in at least nine forward speed or torque ratios and at least one reverse speed or torque ratio. Each forward and reverse speed or torque ratio is attained by engagement of one or more of the torque-transmitting mechanisms (i.e. first clutch 80. second clutch 82. third clutch 84. fourth clutch 86. first brake 32. and second brake 34). as will be explained below. FIG. 3 is a truth table presenting the various combinations of torque-transmitting mechanisms or elements that arc activated or engaged to achieve the various gear states. Actual numerical gear ratios and gear steps of the various gear slates are also presented although it should be appreciated that these numerical values arc exemplary only and that they may be adjusted over significant ranges to accommodate various applications and operational criteria of the transmission 10. An example of the gear ratios that may be obtained using the embodiments of the present invention arc also shown in FIG. 3. Of course, other gear ratios are achievable depending on the gear diameter, gear teeth count and gear configuration selected. To establish reverse gear, the first brake 90, the second brake 92. and the second clutch 82 are engaged or activated. First brake 90 connects first interconnecting member 32. to transmission housing 00 to restrict rotation of first interconnecting member 32 and sun gear 24 relative to housing 100. Second brake 92 connects ninth interconnecting member 66 to housing 100. to restrict rotation of ninth interconnecting member 66 and ring gear 74 relative to housing 100. Second clutch 82 connects sixth interconnecting member 60 to ninth interconnecting member 66. Likewise, the nine forward ratios arc achieved through different combinations of clutch and brake engagement, as shown in FIG. 3. Referring now to FIG. 4, an alternate truth table is presented for the operation of the embodiment of the multiple speed transmission 10. It will be appreciated that the transmission 10 is capable of transmitting torque from the input shaft or member 12 to the output shaft or member 14 in at least ten forward speed or torque ratios and at least" one reverse speed or torque ratio. Each forward and reverse speed or torque ratio is attained by engagement of one or more of the torque-transmitting mechanisms (i.e. first clutch 80. second clutch 82. third clutch 84, fourth clutch 86, first brake 32, and second brake 34). as was described above. Actual numerical gear ratios and gear steps of the various gear slates arc also presented although it should be appreciated that these numerical values are exemplary only and that they may be adjusted over significant ranges to accommodate various applications and operational criteria of the transmission 10. An example of the gear ratios that may be obtained using the embodiments of the present invention are also shown in FIG. 3. Of course, other gear ratios are achievable depending on the gear diameter, gear teeth count and gear configuration selected. It will be appreciated that the foregoing explanation of operation and gear slates of the multiple speed transmission 10 assumes, first of all. that all the clutches and the brakes not specifically referenced in a given gear state are inactive or disengaged and. second of all, that during gear shifts, i.e.. changes of gear stale, between at least adjacent gear states, a clutch or brake engaged or activated in both gear states will remain engaged or activated. Additionally, the present invention contemplates that downshifts follow essentially the reverse sequence of the corresponding upshift (as described above), and several power-on skip-shifts arc possible (e.g. from 1st to 3rd). While the best modes for carrying out the invention have been described in detail, those familiar with the art to which this invention relates will recognize various alternative designs and embodiments for practicing the invention within the scope.of the appended claims. WE CLAIM : 1. A transmission (10) comprising: an input member (12); an output member (14); first, second, third and fourth planetary gear sets (16,18,20,22) each having first, second and third members (24, 26, 28, 42, 44, 46, 52, 54, 56, 72, 74, 76); a first interconnecting member (32) continuously interconnecting the third member (28) of the first planetary gear set (16) with the first member (42) of the second planetary gear set (18); a second interconnecting member (34) continuously interconnecting the third member (46) of the second planetary gear set (18) with the second member (54) of the third planetary gear set (20); a third interconnecting member (36) continuously interconnecting the third member (36) of the third planetary gear set (20) with the second member (74)of the fourth planetary gear set (22); a fourth interconnecting member (38) continuously interconnecting the first member (52) of the third planetary gear set (20) with the first member (72) of the fourth planetary gear set; (22) and six torque transmitting mechanisms (80, 82, 84, 86, 90, 92) selectively engageable to interconnect one of the first, second, and third members with another of the first, second, third members, and a stationary element (100), and wherein the torque transmitting mechanisms are selectively engageable in combinations of at least three to establish at least nine forward speed ratios and at least one reverse speed ratio between the input member and the output member. 2. The transmission as claimed in claim 1 wherein a first of the six torque transmitting mechanisms is selectively engageable to interconnect the second member of the first planetary gear set with the second member of the second planetary gear set. 3. The transmission as claimed in claim 2 wherein a second of the six torque transmitting mechanisms is selectively engageable to interconnect the second member of the second planetary gear set with the third member of the fourth planetary gear set. 4. The transmission as claimed in claim 3 wherein a third of the six torque transmitting mechanisms is selectively engageable to interconnect at least one of the input member and the second member of the first planetary gear set with at least one of the first member of the third planetary gear set and the first member of the fourth planetary gear set. 5. The transmission as claimed in claim 4 wherein a fourth of the six torque transmitting mechanisms is selectively engageable to interconnect at least one of the third member of the first planetary gear set and the first member of the second planetary gear set with at least one of the first member of the third planetary gear set and the first member of the fourth planetary gear set (50). 6. The transmission as claimed in claim 5 wherein a fifth of the six torque transmitting mechanisms is selectively engageable to interconnect the first member of the first planetary gear set with the stationary element. 7. The transmission as claimed in claim 6 wherein a sixth of the six torque transmitting mechanisms is selectively engageable to interconnect the third member of the fourth planetary gear set with the stationary element. 8. The transmission as claimed in claim 1 wherein the first members are sun gears, the second members are carrier members, and the third members are ring gears. 9. The transmission as claimed in claim 1 wherein the input member is continuously interconnected with the second member of the first planetary gear set and wherein the output member is continuously interconnected with the second member of the fourth planetary gear set. 10. The transmission as claimed in claim 1 wherein two of the torque transmitting mechanisms are brakes and four of the torque transmitting mechanisms are clutches. 11. The transmission as claimed in claim 1 wherein the stationary element is a transmission housing. ABSTRACT TITLE : "MULTI-SPEED TRANSMISSION" The invention relates to a transmission is provided having an input member (12), an output member (14), four planetary gear sets (16,18,20,22), a plurality of coupling members (32,34,36,38) and a plurality of torque transmitting devices (80,82,84,86,90,92). Each of the planetary gear sets includes first, second and third members. The torque transmitting devices may include clutches and brakes.

Full Text

MULTI-SPEED TRANSMISSION
CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Application No.
60/900,613 filed on February 8. 2007. The disclosure of the above application is
incorporated herein by reference.
TECHNICAL FIELD The invention relates generally to a multiple speed transmission having a
plurality of planetary gear sets and a plurality of torque transmitting devices and more
particularly to a transmission having nine or more speeds, four planetary gear sets and a
plurality oflorque transmitting devices.
BACKGROUND The statements in this section merely provide background information related
to the present disclosure and may or may not constitute prior art.
A typical multiple speed transmission uses a combination of friction clutches,
planetary gear arrangements and fixed interconnections to achieve a plurality of gear
ratios. The number and physical arrangement of the planetary gear sets, generally, are
dictated by packaging, cost and desired speed ratios.
While current transmissions achieve their intended purpose, the need for new
and improved transmission configurations which exhibit improved performance,
especially from the standpoints of efficiency, responsiveness and smoothness and

improved packaging, primarily reduced • size and weight, is essentially constant.
Accordingly, there is a need for an improved, cost-effective, compact multiple speed
transmission.
SUMMARY A transmission is provided having an input member, an output member, four
planetary gear sets, a plurality of coupling members and a plurality of torque transmitting
devices. Bach of the planetary gear sets includes first, second and third members. The
torque transmitting devices may include clutches and brakes.
One embodiment of the present invention includes an input member, an output
member,, first, second, third and fourth planetary gear sets each having first, second and
third members, a first interconnecting member continuously interconnecting the third
member of the first planetary gear set with the first member of the second planetary gear
set. a second interconnecting member continuously- interconnecting the third member of
the second planetary gear set with the second member of the third planetary gear set. a
third interconnecting member continuously interconnecting the third member of the third
planetary gear set with the second member of the fourth planetary gear set, and a'fourth
interconnecting member continuously interconnecting the first member of the third
planetary gear set with the first member of the fourth planetary gear set. Six torque
transmitting mechanisms are selectively engageable to interconnect one of the first,,
second, and third members with another of the first, second, third members, and a
stationary element. The torque transmitting mechanisms are selectively engageable in

combinations of at least three to establish at least nine forward speed ratios and at least
one reverse speed ratio between the input member and the output member.
In one aspect of the present invention, a first of the six torque transmitting
mechanisms is selectively engageable to interconnect the second member of the first
planetary gear set with the second member of the second planetary gear set.
In another aspect of the present invention, a second of the six torque
transmitting mechanisms is selectively engageable to interconnect the second member of
the second planetary gear set with the third member of the fourth planetary gear set.
In yet another aspect of the present invention, a third of the six torque
transmitting mechanisms is selectively engageable to interconnect at least one of the
input member and the second member of the first planetary gear set with at least one of
the first member of the third planetary gear set and the first member of the fourth
planetary gear set.
In yet another aspect of the present invention, a fourth of the six torque
transmitting mechanisms is selectively engageable to interconnect at least one of the third
member of the first planetary gear set and the first member of the second planetary gear
set with at least one of the first member of the third planetary gear set and the first
member of the fourth planetary gear set.
In yet another aspect of the present .invention, a fifth of the six torque
transmitting mechanisms is selectively engageable to interconnect the first member of the
first planetary gear set with the stationary element.

In ycl another aspect of the present invention, a sixth of the six torque
transmitting mechanisms is selectively engagcable to interconnect the third member of
the fourth planetary gear set with the stationary element.
In yet another aspect of the present invention, the first members arc sun gears,
the second members arc carrier members, and the third members are ring gears. 'n ycl another aspect of the present invention, the input member is
continuously interconnected with the second member of the first planetary gear set and
wherein .the output member is continuously interconnected with the second member of
the fourth planetary gear set. In ycl another aspect of the present invention, two of the lorquc'.transmitting
mechanisms are brakes and four of the torque transmitting mechanisms arc clutches. In yet another aspect of the present invention, the stationary element is a
transmission housing.
Another embodiment of the transmission includes an input member, an output
member, first, second, third and fourth planetary gear sets each having a sun gear, a
carrier, member, and a ring gear, wherein the input member is continuously
interconnected with the carrier member of the first planetary gear set and wherein the
output member is continuously interconnected with the carrier member of the fourth ■
planetary gear set, a first interconnecting member continuously interconnecting the ring
gear of the first planetary gear set with the sun gear of the second planetary gear set. a
second interconnecting member continuously interconnecting the ring gear of the second
planetary gear set with the carrier member of the third planetary gear set. a third
interconnecting member continuously interconnecting the ring gear of the third planetary

gear set with Ihc carrier member of the fourth planetary gear set, and a fourth
interconnecting member continuously interconnecting the sun gear of the third planetary
gear set with the sun gear of the fourth planetary gear set. A first torque transmitting
mechanism is selectively cngageablc to interconnect the carrier member of the first
planetary gear set with the carrier member of the second planetary gear set. a second
torque transmitting mechanism is selectively engageablc to interconnect the carrier
member of the second planetary gear set with the ring gear of the fourth planetary gear
set. a third torque transmitting mechanism is selectively cngageable to interconnect at
least one of the input member and the carrier member of the first planetary gear set with
at least one of the sun gear of the third planetary gear set and the sun gear of the fourth
planetary gear set, a fourth torque transmitting mechanism is selectively engageablc to
interconnect at least one of the ring gear of the first planetary gear set and the sun gear of
the second planetary gear set with at least one of the sun gear of the third planetary gear
set and the sun gear of the fourth planetary gear set, a fifth torque transmitting
mechanism is selectively engageablc to interconnect the sun gear of the llrst planetary
gear set with a stationary element, and a sixth torque transmitting mechanism is
selectively engageablc to interconnect the ring gear of the fourth planetary gear set with
the stationary element. The torque transmitting mechanisms are selectively cngageable in
combinations of at least three to establish at least nine forward speed ratios and at least
one reverse speed ratio between the input member and the output member. The above features and advantages and other features and advantages of the
present invention are readily apparent from the following detailed description of the best

modes for carrying out the-invention when taken in connection with the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS

The drawings described herein are for illustration purposes only and arc not
intended to limit the scope of the present disclosure in any way.
FIG. 1 is a lever diagram of an embodiment of a multiple speed transmission
according to the present invention;
FIG. 2 is a diagrammatic view of an embodiment of a multiple speed
transmission according to the present invention;
FIG. 3 is a truth table presenting the state of engagement of the various torque
transmitting elements in each oflhc available forward and reverse speeds or gear ratios of
the transmission illustrated in FIGS. 1 and 2: and
FIG. 4 is an alternate truth table presenting the slate of engagement of the
various torque transmitting elements in each of the available forward and reverse speeds

or gear ratios of the transmission illustrated in FIGS. 1 and 2.

DESCRIPTION

At the outset, it should be appreciated that the automatic transmission of the
present invention has an arrangement of permanent mechanical connections between the
elements of the four planetary gear sets in common. These mechanical connections

generically link or relate transmission embodiments. A first component or element of a

first planetary gear set is permanently coupled to a first component or element of a

second planetary gear set. A third component or element of the second planetary gear set
is permanently coupled to a second component or element of a third planetary gear set. A
first component or element of the third planetary gear set is permanently coupled to a first
component or element of a fourth planetary gear set. Finally, a third component or
element of the third planetary gear set is permanently coupled to a second component or
element of the fourth planetary gear set.
Referring now to FIG. 1, an embodiment of a multiple speed transmission 10
is illustrated in a lever diagram format. A lever diagram is a schematic representation of
the components of a mechanical device such as an automatic transmission. Each
individual lever represents a planetary gear set wherein the three basic mechanical
components-of the planetary gear arc each represented by a node. Therefore, a single
lever contains three nodes: one for the sun gear, one for the planet gear carrier, and one
for the ring gear. The relative length between the nodes of each lever can be used to
represent the ring-to-sun ratio of each respective gear set. These lever ratios, in turn, arc
used to vary the gear ratios of the transmission in order to achieve an appropriate ratios
and ratio progression. Mechanical couplings or interconnections between the nodes of
the various planetary gear sets arc illustrated by thin, horizontal lines and torque
transmitting devices such as clutches and brakes are presented as interleaved fingers. If
the device is a brake, one set of the fingers is grounded. Further explanation of the
format, purpose and use of lever diagrams can be found in SAE Paper 810102. "The
Lever Analogy: A New Tool in Transmission Analysis" by Ben ford and Leising which is
hereby fully incorporated by reference.

The transmission 10 includes an input shaft or member 12, an output shaft or
member 14, a first planetary gear set 16 having three nodes: a first node 24, a second
node 26 and a third node 28: a second planetary gear set 18 having three nodes: a first
node 42, a second node 44 and a third node 46, a third planetary gear set 20 having three
nodes: a first node 52, a second node 54 and a third node 56, and a fourth planetary gear
set 22 having three nodes: a first node 72. a second node 74 and a third node 76. The input member 12 is coupled to the third node 28 of the first planetary gear
set 16. The output 14 is coupled to the third node 76 of the fourth planetary gear set 22.
The second node 26 of the first planetary gear set 16 is coupled to the first node 42 of the
second planetary gear set 18. The second node 44 of the second planetary gear set 18 is
coupled to the third node 56 of the third planetary gear set 20. The first node 52 of the
third planetary gear set 20 is coupled to the first node 72 of the fourth planetary gear set
22. The second node 54 of the third planetary gear set 20 is coupled to the third node 76
of the fourth planetary gear set 22.
A first clutch 80 selectively connects the third node 28 of the first planetary
gear set 16 to the third node 46 of the second planetary gear set 18. A second clutch 82
selectively connects the third node 46 of the second planetary gear set 18 to the second
node 74 of the fourth planetary gear set 22. A third clutch 84 selectively connects the
input member 12 to the first node 52 of the third planetary gear set 20. A fourth clutch 86
selectively connects the first node 42 of the second planetary gear set 18 to the first node
52 of the third planetary gear set 20. A first brake 90 selectively connects the first node
24 of the first planetary gear set 16 to a ground, stationary element or a transmission

housing 100. A second brake 92 selectively connects the second node 74 of the fourth
planetary gear set 22 to a ground, stationary element, or the transmission housing 100.
Referring now to FIG. 2, ajstick diagram presents a schematic layout of the
embodiment of the multiple speed transmission 10 according to the present invention. In
FIG. 2. the numbering from the lever diagram of FIG. 1 is carried over. The clutches,
brakes and couplings arc correspondingly presented whereas the nodes of the planetary
gear sets now appear as components of planetary gear sets such as sun gears, ring gears.
planet gears and planet gear carriers.
For example, the first planetary gear set 16 includes a sun gear member 24. a
ring gear member 26 and a carrier member 28 that rotatabIy supports a set of pinion gears
30 (only one shown). Bach of the pinion gears 30 arc configured to intermesh with both
sun gear member 24 and ring gear member 26. Sun gear member 24 is connected for
common rotation with a first interconnecting shaft or member 32. Ring gear member 26
is connected for common rotation with a second interconnecting shaft or member 34.
Carrier member 28 is connected for common rotation with a third interconnecting shall or
member 36 and with input shaft 12.
The second planetary gear set, 18 includes a sun gear member 42. a ring gear

member 44 and a carrier member 46 that roialably supports a set of pinion gears 48.

Each of the opinion gears 48 are configured to intermesh with both sun gear member 42
and ring gear member 44. Sun gear member 42 is connected for common rotation with a
fourth interconnecting shaft or member 38. Ring gear member 44 is connected for

common rotation with a fifth interconnecting shaft or member 50. Carrier member 46 is

connected for common rotation with a sixth interconnecting shaft or member 60.

The third planetary gear set 20 includes a sun gear member 52, a ring gear
member 54 and a carrier member 56 that rotalably supports a set of pinion gears 58.
Each of the pinion gears 58 are configured to intermesh with both sun gear member 52
and ring gear member 54. Sun gear member 52 is connected for common rotation with a
seventh interconnecting shaft or member 62. Ring gear member 54 is connected for
common rotation with an eighth interconnecting shaft or member 64. Carrier member 56
is connected for common rotation with fifth interconnecting member 50. The fourth planetary gear set 22 includes a sun gear member 72, a ring gear
member 74 and a carrier member 76 chat rotatably supports a set of pinion gears 78.
Bach of the pinion gears 78 are configured to intermesh with both sun gear member 72
and ring gear member 74. Sun gear member 72 is connected for common rotation with
seventh interconnecting member 62. Ring gear member 74 is connected for common
rotation with a ninth interconnecting shaft or member 66. Carrier member 76 is
connected for common rotation with eighth interconnecting member 64 and with output
shaft 14.
The input shaft 12 is continuously connected to an engine (not shown) or to a
turbine of a torque converter (not shown). The output shaft 14 is continuously connected
with the final drive unit (not shown).
The transmission 10 includes a variety of torque-transmitting mechanisms or
devices including a first clutch 80, a second clutch 82, a third clutch 84, a fourth clutch
86, a first brake 90 and a second brake 92. Firsi clutch 80 is selectively engagablc to
connect third interconnecting member 36 to sixth interconnecting member 60. Second
clutch 82 is selectively engagablc to connect sixth interconnecting member 60 to ninth

interconnecting member 66. Third clutch 84 is selectively cngagablc to connect input
shaft 12 to seventh interconnecting member 62. Fourth clutch 86 is selectively cngagablc
to connect second and fourth interconnecting members 34, 38 to seventh interconnecting
member 62. First brake 90 is selectively engagablc to connect first interconnecting
member 32 to transmission housing 100 to restrict rotation of first interconnecting
member 32 and sun gear 24 relative to housing 100. Second brake 92 is selectively
cngagablc to connect ninth interconnecting member 66 to housing 100 to restrict rotation
of ninth interconnecting member 66 and ring gear 74 relative to housing 100. Referring now to FIGS. 2 and 3, the operation of the embodiment of the
multiple speed transmission 10 will be described. It will be appreciated that the
transmission 10 is capable of transmitting torque from the input shaft or member 12 to
the output shaft or member 14 in at least nine forward speed or torque ratios and at least
one reverse speed or torque ratio. Each forward and reverse speed or torque ratio is
attained by engagement of one or more of the torque-transmitting mechanisms (i.e. first
clutch 80. second clutch 82. third clutch 84. fourth clutch 86. first brake 32. and second
brake 34). as will be explained below. FIG. 3 is a truth table presenting the various
combinations of torque-transmitting mechanisms or elements that arc activated or engaged to achieve the various gear states. Actual numerical gear ratios and gear steps of
the various gear slates are also presented although it should be appreciated that these
numerical values arc exemplary only and that they may be adjusted over significant
ranges to accommodate various applications and operational criteria of the transmission
10. An example of the gear ratios that may be obtained using the embodiments of the

present invention arc also shown in FIG. 3. Of course, other gear ratios are achievable
depending on the gear diameter, gear teeth count and gear configuration selected. To establish reverse gear, the first brake 90, the second brake 92. and the
second clutch 82 are engaged or activated. First brake 90 connects first interconnecting
member 32. to transmission housing 00 to restrict rotation of first interconnecting
member 32 and sun gear 24 relative to housing 100. Second brake 92 connects ninth
interconnecting member 66 to housing 100. to restrict rotation of ninth interconnecting
member 66 and ring gear 74 relative to housing 100. Second clutch 82 connects sixth
interconnecting member 60 to ninth interconnecting member 66. Likewise, the nine
forward ratios arc achieved through different combinations of clutch and brake
engagement, as shown in FIG. 3.
Referring now to FIG. 4, an alternate truth table is presented for the operation
of the embodiment of the multiple speed transmission 10. It will be appreciated that the
transmission 10 is capable of transmitting torque from the input shaft or member 12 to
the output shaft or member 14 in at least ten forward speed or torque ratios and at least"
one reverse speed or torque ratio. Each forward and reverse speed or torque ratio is
attained by engagement of one or more of the torque-transmitting mechanisms (i.e. first
clutch 80. second clutch 82. third clutch 84, fourth clutch 86, first brake 32, and second
brake 34). as was described above. Actual numerical gear ratios and gear steps of the
various gear slates arc also presented although it should be appreciated that these
numerical values are exemplary only and that they may be adjusted over significant
ranges to accommodate various applications and operational criteria of the transmission
10. An example of the gear ratios that may be obtained using the embodiments of the

present invention are also shown in FIG. 3. Of course, other gear ratios are achievable
depending on the gear diameter, gear teeth count and gear configuration selected. It will be appreciated that the foregoing explanation of operation and gear
slates of the multiple speed transmission 10 assumes, first of all. that all the clutches and
the brakes not specifically referenced in a given gear state are inactive or disengaged and.
second of all, that during gear shifts, i.e.. changes of gear stale, between at least adjacent
gear states, a clutch or brake engaged or activated in both gear states will remain engaged
or activated. Additionally, the present invention contemplates that downshifts follow
essentially the reverse sequence of the corresponding upshift (as described above), and
several power-on skip-shifts arc possible (e.g. from 1st to 3rd).
While the best modes for carrying out the invention have been described in
detail, those familiar with the art to which this invention relates will recognize various
alternative designs and embodiments for practicing the invention within the scope.of the
appended claims.

WE CLAIM :
1. A transmission (10) comprising:
an input member (12);
an output member (14);
first, second, third and fourth planetary gear sets (16,18,20,22) each
having first, second and third members (24, 26, 28, 42, 44, 46, 52, 54,
56, 72, 74, 76);
a first interconnecting member (32) continuously interconnecting the
third member (28) of the first planetary gear set (16) with the first
member (42) of the second planetary gear set (18);
a second interconnecting member (34) continuously interconnecting the
third member (46) of the second planetary gear set (18) with the
second member (54) of the third planetary gear set (20);
a third interconnecting member (36) continuously interconnecting the
third member (36) of the third planetary gear set (20) with the second
member (74)of the fourth planetary gear set (22);
a fourth interconnecting member (38) continuously interconnecting the
first member (52) of the third planetary gear set (20) with the first
member (72) of the fourth planetary gear set; (22) and
six torque transmitting mechanisms (80, 82, 84, 86, 90, 92) selectively
engageable to interconnect one of the first, second, and third members
with another of the first, second, third members, and a stationary element
(100), and
wherein the torque transmitting mechanisms are selectively engageable in
combinations of at least three to establish at least nine forward speed
ratios and at least one reverse speed ratio between the input member and
the output member.

2. The transmission as claimed in claim 1 wherein a first of the six torque
transmitting mechanisms is selectively engageable to interconnect the
second member of the first planetary gear set with the second member
of the second planetary gear set.
3. The transmission as claimed in claim 2 wherein a second of the six torque
transmitting mechanisms is selectively engageable to interconnect the
second member of the second planetary gear set with the third member
of the fourth planetary gear set.
4. The transmission as claimed in claim 3 wherein a third of the six torque
transmitting mechanisms is selectively engageable to interconnect at least
one of the input member and the second member of the first planetary
gear set with at least one of the first member of the third planetary gear
set and the first member of the fourth planetary gear set.
5. The transmission as claimed in claim 4 wherein a fourth of the six torque
transmitting mechanisms is selectively engageable to interconnect at least
one of the third member of the first planetary gear set and the first
member of the second planetary gear set with at least one of the first
member of the third planetary gear set and the first member of the fourth
planetary gear set (50).
6. The transmission as claimed in claim 5 wherein a fifth of the six torque
transmitting mechanisms is selectively engageable to interconnect the first
member of the first planetary gear set with the stationary element.

7. The transmission as claimed in claim 6 wherein a sixth of the six torque
transmitting mechanisms is selectively engageable to interconnect the
third member of the fourth planetary gear set with the stationary
element.
8. The transmission as claimed in claim 1 wherein the first members are sun
gears, the second members are carrier members, and the third members
are ring gears.
9. The transmission as claimed in claim 1 wherein the input member is
continuously interconnected with the second member of the first planetary
gear set and wherein the output member is continuously interconnected
with the second member of the fourth planetary gear set.
10. The transmission as claimed in claim 1 wherein two of the torque
transmitting mechanisms are brakes and four of the torque transmitting
mechanisms are clutches.
11. The transmission as claimed in claim 1 wherein the stationary element is a transmission housing.

ABSTRACT

TITLE : "MULTI-SPEED TRANSMISSION"
The invention relates to a transmission is provided having an input member (12),
an output member (14), four planetary gear sets (16,18,20,22), a plurality of
coupling members (32,34,36,38) and a plurality of torque transmitting devices
(80,82,84,86,90,92). Each of the planetary gear sets includes first, second and
third members. The torque transmitting devices may include clutches and
brakes.

MULTI-SPEED TRANSMISSION

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