Patent Publication Number: US-8979700-B2

Title: Multi-speed transmission

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This continuation application claims the benefit of U.S. application Ser. No. 13/488,017 filed on Jun. 4, 2012, which claims the benefit of Provisional Application No. 61/602,846, filed Feb. 24, 2012. The entire contents of the above applications are incorporated herein by reference. 
    
    
     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 speeds, four planetary gear sets and a plurality of torque 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. Each of the planetary gear sets includes first, second and third members. The torque transmitting devices are for example clutches and brakes. 
     In another embodiment of the present invention, a transmission is provided having 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. The output member is continuously interconnected with the carrier member of the first planetary gear set, the ring gear of the third planetary gear set and the ring gear of the fourth planetary gear set. 
     In yet another embodiment of the present invention, a first interconnecting member continuously interconnects the ring gear of the first planetary gear set with the carrier member of the second planetary gear set. 
     In yet another embodiment of the present invention, a second interconnecting member continuously interconnects the carrier member of the first planetary gear set with the ring gear of the third planetary gear set and the ring gear of the fourth planetary gear set. 
     In yet another embodiment of the present invention, a third interconnecting member continuously interconnects the ring gear of the second planetary gear set with the carrier member of the third planetary gear set. 
     In yet another embodiment of the present invention, a fourth interconnecting member continuously interconnects the carrier member of the third planetary gear set with the carrier member of the fourth planetary gear set. 
     In yet another embodiment of the present invention, a first torque transmitting device is selectively engageable to interconnect the sun gear of the third planetary gear set with the input member. 
     In yet another embodiment of the present invention, a second torque transmitting device is selectively engageable to interconnect the ring gear of the second planetary gear set and the carrier member of the third planetary gear set with the sun gear of the second planetary gear set and the input member. 
     In yet another embodiment of the present invention, a third torque transmitting device is selectively engageable to interconnect the carrier member of the fourth planetary gear set with the ring gear of the fourth planetary gear set. 
     In yet another embodiment of the present invention, a fourth torque transmitting device is selectively engageable to interconnect the sun gear of the third planetary gear set with the stationary member. 
     In yet another embodiment of the present invention, a fifth torque transmitting device is selectively engageable to interconnect the sun gear of the fourth planetary gear set with the stationary member. 
     In yet another embodiment of the present invention, a sixth torque transmitting device is selectively engageable to interconnect the carrier member of the fourth planetary gear set with the stationary member. 
     In yet another embodiment of the present invention, a seventh torque transmitting device is selectively engageable to interconnect the sun gear of the first planetary gear set with the stationary member. 
     In yet another embodiment of the present invention, the torque transmitting devices are each selectively engageable in combinations of at least two to establish a plurality of forward speed ratios and at least one reverse speed ratio between the input member and the output member. 
     In still another embodiment of the present invention, a transmission is provided that has an input member, an output member, first, second, third and fourth planetary gear sets each having first, second and third members. The output member is continuously interconnected the second member of the first planetary gear set and the third member of the third planetary gear set. A first interconnecting member continuously interconnects the first member of the first planetary gear set with the second member of the second planetary gear set. A second interconnecting member continuously interconnects the second member of the first planetary gear set with the third member of the third planetary gear set. A third interconnecting member continuously interconnects the third member of the second planetary gear set with the second member of the third planetary gear set. A fourth interconnecting member continuously interconnects the second member of the third planetary gear set with the third member of the fourth planetary gear set. A first torque transmitting device is selectively engageable to interconnect the first member of the fourth planetary gear set with the first member of the second planetary gear set and the input member. A second torque transmitting device is selectively engageable to interconnect the third member of the second planetary gear set and the second member of the third planetary gear set with the first member of the second planetary gear set and the input member. A third torque transmitting device is selectively engageable to interconnect the third member of the fourth planetary gear set and the second member of the third planetary gear set with the second member of the first planetary gear set, the output member and the third member of the third planetary gear set. A fourth torque transmitting device is selectively engageable to interconnect the first member of the fourth planetary gear set with the stationary member. A fifth torque transmitting device is selectively engageable to interconnect the second member of the fourth planetary gear set with the stationary member. A sixth torque transmitting device is selectively engageable to interconnect the third member of the fourth planetary gear set and the second member of the third planetary gear set with the stationary member. A seventh torque transmitting device is selectively engageable to interconnect the third member of the first planetary gear set with the stationary member. The torque transmitting devices are each selectively engageable in combinations of at least two to establish a plurality of forward speed ratios and at least one reverse speed ratio between the input member and the output member. The third member of the first planetary gear set, the first member of the second planetary gear set, the first member of the third planetary gear set and the first member of the fourth planetary gear set are sun gears, the second member of the first planetary gear set, the second member of the second planetary gear set, the second member of the third planetary gear set and the second member of the fourth planetary gear set are carrier members, the first member of the first planetary gear set, the third member of the second planetary gear set, the third member of the third planetary gear set and the third member of the fourth planetary gear set are ring gears. 
     Further features, aspects and advantages of the present invention will become apparent by reference to the following description and appended drawings wherein like reference numbers refer to the same component, element or feature. 
    
    
     
       DRAWINGS 
       The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. 
         FIG. 1  is a lever diagram of an embodiment of a nine speed transmission according to the present invention; 
         FIG. 2  is a diagrammatic illustration of an embodiment of a nine 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 of the available forward and reverse speeds or gear ratios of the transmissions illustrated in  FIGS. 1 and 2 ; 
         FIG. 4  is a diagrammatic illustration of another embodiment of a nine speed transmission according to the present invention; 
         FIG. 5  is another truth table presenting an alternate state of engagement of the various torque transmitting elements in each of the available forward and reverse speeds or gear ratios of the transmissions illustrated in  FIGS. 1 and 4 ; and 
         FIG. 6  is a diagrammatic illustration of another embodiment of a nine speed transmission having a compound planetary gear set, in accordance with the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. 
     At the outset, it should be appreciated that the embodiments of the multi-speed automatic transmissions of the present invention have an arrangement of permanent mechanical connections between the elements of the four planetary gear sets. For example, a first component or element of a first planetary gear set is permanently coupled to a second component or element of the second planetary gear set. A second component or element of the first planetary gear set is permanently coupled a third component or element of the third planetary gear set and to a third component or element of the fourth planetary gear set. A third component or element of the second planetary gear set is permanently coupled to a second component or element of the third planetary gear set and a second component or element of the fourth planetary gear set. A second component or element of the third planetary gear set is permanently coupled a second component or element of the fourth planetary gear set. A third component or element of the third planetary gear set is permanently coupled a third component or element of the fourth planetary gear set. 
     Referring now to  FIG. 1 , an embodiment of a nine 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 are 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. In some cases, two levers may be combined into a single lever having more than three nodes (typically four nodes). For example, if two nodes on two different levers are interconnected through a fixed connection they may be represented as a single node on a single lever. 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, are 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 are illustrated by thin, horizontal lines and torque transmitting devices such as clutches and brakes are presented as interleaved fingers. 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 Benford and Leising which is hereby fully incorporated by reference. 
     The transmission  10  includes an input shaft or member  12 , a first planetary gear set  14 , a second planetary gear set  16 , a third planetary gear set  18  and a fourth planetary gear set  20  and an output shaft or member  22 . The first planetary gear set  14  has three nodes: a first node  14 A, a second node  14 B and a third node  14 C. The second planetary gear set  16  has three nodes: a first node  16 A, a second node  16 B and a third node  16 C. In the lever diagram of  FIG. 1 , the levers for the third planetary gear set  18  and the fourth planetary gear set  20  have been combined into a single four node lever having: a first node  18 A, a second node  20 A, a third node  18 B,  20 B, and a fourth node  18 C,  20 C. Thus, the second member  18 B of the third planetary gear set  18  is coupled directly to the second member  20 B of the fourth planetary gear set  20  and the third member  18 C of the third planetary gear set  18  is coupled directly to the third member  20 C of the fourth planetary gear set  20 . 
     The input member  12  is continuously coupled to the first node  16 A of the second planetary gear set  16 . The output member  22  is coupled to the second node  14 B of the first planetary gear set  14  and the fourth node  18 C,  20 C of the combined levers of the third and fourth planetary gear sets  18 ,  20 . The first node  14 A of the first planetary gear set  14  is coupled to the second node  16 B of the second planetary gear set  16 . The third node  16 C of the second planetary gear set  16  is coupled to the third node  18 B,  20 B of the combined levers of the third and fourth planetary gear sets  18 ,  20 . 
     A first clutch  24  selectively connects the first node  16 A of the second planetary gear set  16  and the input member or shaft  12  with the first node  18 A of the combined levers of the third and fourth planetary gear sets  18 ,  20 . A second clutch  26  selectively connects the first node  16 A of the second planetary gear set  16  and the input member or shaft  12  with the third node  18 B, 20 B of the combined levers of the third and fourth planetary gear sets  18 ,  20  and the third node  16 C of the second planetary gear set  16 . A third clutch  28  selectively connects the third node  18 B, 20 B of the combined levers of the third and fourth planetary gear sets  18 ,  20  with the fourth node  18 C, 20 C of the combined levers of the third and fourth planetary gear sets  18 ,  20  and the second node  14 B of the first planetary gear set  14 . A first brake  30  selectively connects the first node  18 A of the combined levers of the third and fourth planetary gear sets  18 ,  20  with a stationary member or transmission housing  50 . A second brake  32  selectively connects the second node  20 A of the combined levers of the third and fourth planetary gear sets  18 ,  20  with a stationary member or transmission housing  50 . A third brake  34  selectively connects the third node  18 B, 20 B of the combined levers of the third and fourth planetary gear sets  18 ,  20  and the third node  16 C of the second planetary gear set  16  with the stationary member or transmission housing  50 . A fourth brake  36  selectively connects the third node  14 C of the first planetary gear set  14  with the stationary member or transmission housing  50 . In an alternate embodiment, the present invention contemplates the inclusion of a one-way clutch  38 . One-way clutch  38  selectively connects the third node  18 B, 20 B of the combined levers of the third and fourth planetary gear sets  18 ,  20  and the third node  16 C of the second planetary gear set  16  with the stationary member or transmission housing  50 . 
     Referring now to  FIG. 2 , a stick diagram presents a schematic layout of an embodiment of the nine 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 and couplings are 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. In an embodiment of the present invention, the four planetary gear sets  14 ,  16 ,  18  and  20  are simple planetary gear sets, as described below. However, the present invention contemplates other embodiments that replace the simple planetary gear sets with all or a combination of compound planetary gear sets having two or more sets of planet pinions supported by a single carrier member. 
     For example, the planetary gear set  14  includes a sun gear member  14 C, a ring gear member  14 A and a planet gear carrier member  14 B that rotatably supports a set of planet gears  14 D (only one of which is shown). The sun gear member  14 C is connected for common rotation with a first shaft or interconnecting member  42 . The ring gear member  14 A is connected for common rotation with a second shaft or interconnecting member  44 . The planet carrier member  14 B is connected for common rotation with a third shaft or interconnecting member  46  and the output shaft or member  22 . The planet gears  14 D are each configured to intermesh with both the sun gear member  14 C and the ring gear member  14 A. 
     The planetary gear set  16  includes a sun gear member  16 A, a ring gear member  16 C and a planet gear carrier member  16 B that rotatably supports a set of planet gears  16 D (only one of which is shown). The sun gear member  16 A is connected for common rotation with the input shaft or member  12 . The ring gear member  16 C is connected for common rotation with a fourth shaft or interconnecting member  48 . The planet carrier member  16 B is connected for common rotation with the second shaft or interconnecting member  44 . The planet gears  16 D are each configured to intermesh with both the sun gear member  16 A and the ring gear member  16 C. 
     The planetary gear set  18  includes a sun gear member  18 A, a ring gear member  18 C and a planet gear carrier member  18 B that rotatably supports a set of planet gears  18 D (only one of which is shown). The sun gear member  18 A is connected for common rotation with a fifth shaft or interconnecting member  52 . The ring gear member  18 C is connected for common rotation with the third shaft or interconnecting member  46  and with a sixth shaft or interconnecting member  54 . The planet carrier member  18 B is connected for common rotation with the fourth shaft or interconnecting member  48  and with a seventh shaft or interconnecting member  56 . The planet gears  18 D are each configured to intermesh with both the sun gear member  18 A and the ring gear member  18 C. 
     The planetary gear set  20  includes a sun gear member  20 A, a ring gear member  20 C and a planet gear carrier member  20 B that rotatably supports a set of planet gears  20 D (only one of which is shown). The sun gear member  20 A is connected for common rotation with an eighth shaft or interconnecting member  58 . The ring gear member  20 C is connected for common rotation with the sixth shaft or interconnecting member  54  and with a ninth shaft or interconnecting member  60 . The planet carrier member  20 B is connected for common rotation with the seventh shaft or interconnecting member  56  and with a tenth shaft or interconnecting member  62 . The planet gears  20 D are each configured to intermesh with both the sun gear member  20 A and the ring gear member  20 C. 
     The input shaft or member  12  is continuously connected to an engine (not shown) through a turbine of a torque converter, fluid coupling, friction launch clutch or other starting device (not shown). The output shaft or member  22  is continuously connected with the final drive unit or transfer case (not shown). 
     The torque-transmitting mechanisms or clutches  24 ,  26 ,  28  and brakes  30 ,  32 ,  34  and  36  allow for selective interconnection of the shafts or interconnecting members, members of the planetary gear sets and the housing. The clutches  24 ,  26 ,  28  and brakes  30 ,  32 ,  34  and  36  are friction, dog or synchronizer type mechanisms or the like. For example, the first clutch  24  is selectively engageable to connect the input shaft or member  12  with the fifth shaft or interconnecting member  52 . The second clutch  26  is selectively engageable to connect the input shaft or member  12  with the fourth shaft or interconnecting member  48 . The third clutch  28  is selectively engageable to connect the ninth shaft or interconnecting member  60  with the tenth shaft or interconnecting member  62 . The first brake  30  is selectively engageable to connect the fifth shaft or interconnecting member  52  with the stationary element or the transmission housing  50  in order to restrict the member  52  from rotating relative to the transmission housing  50 . The second brake  32  is selectively engageable to connect the eighth shaft or interconnecting member  58  with the stationary element or the transmission housing  50  in order to restrict the member  58  from rotating relative to the transmission housing  50 . The third brake  34  is selectively engageable to connect the tenth shaft or interconnecting member  62  with the stationary element or the transmission housing  50  in order to restrict the member  62  from rotating relative to the transmission housing  50 . The fourth brake  36  is selectively engageable to connect the first shaft or interconnecting member  42  with the stationary element or the transmission housing  50  in order to restrict the member  42  from rotating relative to the transmission housing  50 . 
     Alternatively, in another embodiment of the present invention one-way clutch or freewheeler  38  selectively connects the carrier members  18 B and  20 B of the third and fourth planetary gear sets  18 ,  20  and the ring gear  16 C of the second planetary gear set  16  with the transmission housing  50 . Accordingly, a first to a second gear ratio shift is achieved through the use of freewheeler  38 . In the instant embodiment, the third brake  34  is applied in reverse and first gear (only for engine braking), as shown in the table of  FIG. 3 . 
     In yet another embodiment of the present invention, the third clutch  28  is selectively engageable to connect the eighth shaft or interconnecting member  58  with the tenth shaft or interconnecting member  62 , instead of connecting the ninth shaft or interconnecting member  60  to the tenth shaft or interconnecting member  62 , as shown in dashed lines in  FIG. 2 . In other words, clutch  28  is selectively engageable to connect carrier member  20 B with the sun gear  20 A, instead of connecting the carrier member  20 B with the ring gear  20 C. 
     Referring now to  FIG. 2  and  FIG. 3 , the operation of the nine speed transmission  10  will be described. It will be appreciated that transmission  10  is capable of transmitting torque from the input shaft or member  12  to the output shaft or member  22  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 two or more of the torque-transmitting mechanisms (i.e. first clutch  24 , second clutch  26 , third clutch  28 , first brake  30 , second brake  32 , third brake  34  and fourth brake  36 ), as will be explained below.  FIG. 3  is a truth table that present the various combinations of torque-transmitting mechanisms that are activated or engaged to achieve the various gear states. An “X” in the box means that the particular referenced clutch or brake is engaged to achieve the desired gear state. An “O” represents that the particular torque transmitting device (i.e. a brake or clutch) is on or active, but not carrying torque. Actual numerical gear ratios of the various gear states are 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 . Of course, other gear ratios are achievable depending on the gear diameter, gear teeth count and gear configuration selected. 
     With specific reference to  FIG. 3 , a truth table is presented illustrating a state of engagement of the various torque transmitting elements in each of the available forward and reverse speeds or gear ratios of the transmission  10 . Accordingly, a reverse gear is established through the engagement or activation of the first clutch  24  and third brake  34 . The first clutch  24  connects the input shaft or member  12  with the fifth shaft or interconnecting member  52 . The third brake  34  connects the tenth shaft or interconnecting member  62  with the stationary element or the transmission housing  50  in order to restrict the member  62  from rotating relative to the transmission housing  50 . Likewise, the nine forward ratios are achieved through different combinations of clutch and brake engagement, as shown in  FIG. 3 . 
     Referring now to  FIG. 4 , a stick diagram presents a schematic layout of yet another embodiment of the nine speed transmission  10 ′ according to the present invention. In  FIG. 4 , the numbering from the lever diagram of  FIG. 1  and the previous embodiment of  FIG. 2  is carried over. Transmission  10 ′ has the four planetary gear sets  14 ,  16 ,  18  and  20  as described with respect to transmission  10  above. The two of the three rotating clutches  24  and  28  have been reconfigured as described below and the second clutch brake  26  remains the same as configured and described with respect to transmission  10  above. Three of the four brakes  30 ,  32  and  34  have been reconfigured as described below and the fourth brake  36  remains the same as configured and described with respect to transmission  10  above. Moreover, interconnecting members or shafts  42 ,  44 ,  46  and  48  are also configured and connected to the respective components of the planetary gear sets as described above with respect to transmission  10 . However, transmission  10 ′ has several distinct differences relative to transmission  10 . For example, interconnecting member or shaft  52  has been eliminated and replaced with a reconfigured interconnecting member or shaft  52 ′, interconnecting member or shaft  54  has been eliminated and replaced with a reconfigured interconnecting member or shaft  54 ′, interconnecting member or shaft  58  has been eliminated and replaced with a reconfigured interconnecting member or shaft  58 ′. Reconfigured interconnecting member or shaft  52 ′ connects the sun gear  18 A of the third planetary gear set  18  to the carrier member  20 B of the fourth planetary gear set  20  and to brake  32 . Reconfigured interconnecting member or shaft  54 ′ connects the carrier member  18 B of the third planetary gear set  18  to the ring gear  20 C of the fourth planetary gear set  20  and to brake  32 . Reconfigured interconnecting member or shaft  58 ′ connects the sun gear  20 A of the fourth planetary gear set  20  to first clutch  24  and to the first brake  30 . Interconnecting members or shafts  60  and  62  have been eliminated. Furthermore, the first clutch  24  has been eliminated and replaced with a reconfigured second clutch  24 ′, the third clutch  28  has been eliminated and replaced with a reconfigured third clutch  28 ′, the first brake  30  has been eliminated and replaced with a reconfigured first brake  30 ′, the second brake  32  has been eliminated and replaced with a reconfigured second brake  32 ′ and the third brake  34  has been eliminated and replaced with a reconfigured third brake  34 ′. Reconfigured first clutch  24 ′ selectively connects for common rotation input shaft  12  with reconfigured interconnecting member or shaft  58 ′. Reconfigured third clutch  28 ′ selectively connects for common rotation interconnecting shaft  46  and reconfigured interconnecting member or shaft  54 ′. Reconfigured first brake  30 ′ selectively connects reconfigured interconnecting member or shaft  58 ′ with the stationary element or the transmission housing  50  in order to restrict the member  58 ′ from rotating relative to the transmission housing  50 . Reconfigured second brake  32 ′ selectively connects reconfigured interconnecting member or shaft  52 ′ with the stationary element or the transmission housing  50  in order to restrict the member  52 ′ from rotating relative to the transmission housing  50 . Reconfigured second brake  34 ′ selectively connects reconfigured interconnecting member or shaft  54 ′ with the stationary element or the transmission housing  50  in order to restrict the member  54 ′ from rotating relative to the transmission housing  50 . 
     With specific reference to  FIG. 5 , a truth table is shown similar to  FIG. 3  illustrating a state of engagement of the various torque transmitting elements in each of the available forward and reverse speeds or gear ratios of the transmission  10 ′. For example, a reverse gear is established through the engagement or activation of the first reconfigured clutch  24 ′ and third reconfigured brake  34 ′. The first reconfigured clutch  24 ′ connects the input shaft or member  12  with the reconfigured shaft or interconnecting member  58 ′. The third reconfigured brake  34 ′ connects the reconfigured shaft or interconnecting member  54 ′ with the stationary element or the transmission housing  50  in order to restrict the member  54 ′ from rotating relative to the transmission housing  50 . Likewise, the nine forward ratios are achieved through different combinations of clutch and brake engagement, as shown in  FIG. 5 . 
     It will be appreciated that the foregoing explanation of operation and gear states of the nine speed transmissions  10  and  10 ′ assumes, first of all, that all the clutches 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 state, between at least adjacent gear states, a clutch engaged or activated in both gear states will remain engaged or activated. 
     The present invention contemplates other embodiments of a multi-speed planetary gear set transmission. For example, in yet another embodiment the third clutch  28  is eliminated to produce an eight speed planetary gear set transmission. In still another embodiment of the present invention, first brake  30  is eliminated to produce a seven speed planetary gear set transmission. Moreover, planetary gear sets  18  and  20  may be replaced with a single planetary gear set. In yet another embodiment, both the third clutch  28  and first brake  30  are eliminated to produce a six speed planetary gear set transmission. 
     Referring now to  FIG. 6 , a schematic layout of yet another embodiment of a nine speed transmission  100  according to the present invention is illustrated. In the instant embodiment, transmission  100  has four planetary gear sets  114 ,  116 ,  118  and  120  supported and enclosed by a transmission housing (not shown) having a ground or stationary member  150  attached to the housing. Planetary gear sets  114 ,  116  and  118  are simple planetary gear sets and planetary gear set  120  is a compound planetary gear set. 
     Accordingly, the simple planetary gear set  114  includes a sun gear member  114 C, a ring gear member  114 A and a planet gear carrier member  114 B that rotatably supports a set of planet gears  114 D (only one of which is shown). The sun gear member  114 C is connected for common rotation with a first shaft or interconnecting member  142 . The ring gear member  114 A is connected for common rotation with a second shaft or interconnecting member  144 . The planet carrier member  114 B is connected for common rotation with a third shaft or interconnecting member  146  and an output shaft or member  122 . The planet gears  114 D are each configured to intermesh with both the sun gear member  114 C and the ring gear member  114 A. 
     The simple planetary gear set  116  includes a sun gear member  116 A, a ring gear member  116 C and a planet gear carrier member  116 B that rotatably supports a set of planet gears  116 D (only one of which is shown). The sun gear member  116 A is connected for common rotation with an input shaft or member  112 . The ring gear member  116 C is connected for common rotation with a fourth shaft or interconnecting member  148 . The planet carrier member  1168  is connected for common rotation with the second shaft or interconnecting member  144 . The planet gears  116 D are each configured to intermesh with both the sun gear member  116 A and the ring gear member  116 C. 
     The simple planetary gear set  118  includes a sun gear member  118 A, a ring gear member  118 C and a planet gear carrier member  118 B that rotatably supports a set of planet gears  118 D (only one of which is shown). The sun gear member  118 A is connected for common rotation with a fifth shaft or interconnecting member  152  and with a sixth shaft or interconnecting member  154 . The ring gear member  118 C is connected for common rotation with the third shaft or interconnecting member  146 . The planet carrier member  118 B is connected for common rotation with the fourth shaft or interconnecting member  148  and with a seventh shaft or interconnecting member  156 . The planet gears  118 D are each configured to intermesh with both the sun gear member  118 A and the ring gear member  118 C. 
     The compound planetary gear set  120  includes a sun gear member  120 A, a ring gear member  120 C and a planet gear carrier member  1208  that rotatably supports a first set of planet gears  120 D (only one of which is shown) and a second set of planet gears  120 E (only one of which is shown). The sun gear member  120 A is connected for common rotation with the fifth shaft or interconnecting member  152 . The ring gear member  120 C is connected for common rotation with an eighth shaft or interconnecting member  158 . The planet carrier member  120 B is connected for common rotation with the seventh shaft or interconnecting member  156  and with a ninth shaft or interconnecting member  160 . The first set of planet gears  120 D are each configured to intermesh with both the sun gear member  120 A and the second set of planet gears  120 E. The second set of planet gears  120 E are each configured to intermesh with both the ring gear member  120 C and the first set of planet gears  120 D. 
     The input shaft or member  112  is continuously connected to an engine (not shown) through a turbine of a torque converter, fluid coupling, friction launch clutch or other starting device (not shown). The output shaft or member  122  is continuously connected with the final drive unit or transfer case (not shown). 
     Transmission  100  further includes a plurality of torque-transmitting mechanisms or clutches  124 ,  126 ,  128  and brakes  130 ,  132 ,  134  and  136  that allow for selective interconnection of the shafts or interconnecting members, members of the planetary gear sets and the housing. The clutches  124 ,  126 ,  128  and brakes  130 ,  132 ,  134  and  136  are friction, dog or synchronizer type mechanisms or the like. For example, the first clutch  124  is selectively engageable to connect the input shaft or member  112  with the sixth shaft or interconnecting member  154 . The second clutch  126  is selectively engageable to connect the input shaft or member  112  with the fourth shaft or interconnecting member  148 . The third clutch  128  is selectively engageable to connect the third shaft or interconnecting member  146  with the seventh shaft or interconnecting member  156 . The first brake  130  is selectively engageable to connect the sixth shaft or interconnecting member  154  with the stationary member or the transmission housing  150  in order to restrict the member  154  from rotating relative to the transmission housing  150 . The second brake  132  is selectively engageable to connect the ninth shaft or interconnecting member  160  with the stationary member or the transmission housing  150  in order to restrict the member  160  from rotating relative to the transmission housing  150 . The third brake  134  is selectively engageable to connect the eighth shaft or interconnecting member  158  with the stationary element or the transmission housing  150  in order to restrict the member  158  from rotating relative to the transmission housing  150 . The fourth brake  136  is selectively engageable to connect the first shaft or interconnecting member  142  with the stationary member or the transmission housing  150  in order to restrict the member  142  from rotating relative to the transmission housing  150 . 
     The description of the invention is merely exemplary in nature and variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.