Patent Publication Number: US-10323723-B2

Title: Multi-speed planetary transmission

Description:
RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Application Ser. No. 62/400,914, filed Sep. 28, 2016, titled MULTI-SPEED PLANETARY TRANSMISSION, docket AT-P16008USP1, the entire disclosure of which is expressly incorporated by reference herein. 
    
    
     FIELD OF THE DISCLOSURE 
     The present disclosure relates to a multi-speed transmission and in particular to a multi-speed transmission including a plurality of planetary gearsets and a plurality of selective couplers to achieve at least nine forward speed ratios and at least one reverse speed ratio. 
     BACKGROUND OF THE DISCLOSURE 
     Multi-speed transmissions use a plurality of planetary gearsets, selective couplers, interconnectors, and additional elements to achieve a plurality of forward and reverse speed ratios. Exemplary multi-speed transmissions are disclosed in US Published Patent Application No. 2016/0047440, Ser. No. 14/457,592, titled MULTI-SPEED TRANSMISSION, filed Aug. 12, 2014, the entire disclosure of which is expressly incorporated by reference herein. 
     SUMMARY 
     The present disclosure provides a multi-speed transmission including a plurality of planetary gearsets and a plurality of selective couplers to achieve at least nine forward speed ratios. The plurality of planetary gearsets may include a first planetary gearset, a second planetary gearset, a third planetary gearset, and a fourth planetary gearset. The plurality of selective couplers may include a number of clutches and a number of brakes. In one example, the present disclosure provides a multi-speed transmission having four planetary gearsets and six selective couplers. The six selective couplers may include three clutches and three brakes. 
     In some instances throughout this disclosure and in the claims, numeric terminology, such as first, second, third, and fourth, is used in reference to various gearsets, gears, gearset components, interconnectors, selective couplers, and other components. Such use is not intended to denote an ordering of the components. Rather, numeric terminology is used to assist the reader in identifying the component being referenced and should not be narrowly interpreted as providing a specific order of components. For example, a first planetary gearset identified in the drawings may support any one of the plurality of planetary gearsets recited in the claims, including the first planetary gearset, the second planetary gearset, the third planetary gearset, and the fourth planetary gearset, depending on the language of the claims. 
     According to an exemplary embodiment of the present disclosure, a transmission is provided. The transmission comprising at least one stationary member; an input member; a plurality of planetary gearsets operatively coupled to the input member; a plurality of selective couplers operatively coupled to the plurality of planetary gearsets; and an output member operatively coupled to the input member through the plurality of planetary gearsets. Each planetary gearset of the plurality of planetary gearsets includes a sun gear, a plurality of planet gears operatively coupled to the sun gear, a planet carrier operatively coupled to the plurality of planet gears, and a ring gear operatively coupled to the plurality of planet gears. The plurality of planetary gearsets includes a first planetary gearset, a second planetary gearset, a third planetary gearset, and a fourth planetary gearset. Each of the first planetary gearset, the second planetary gearset, the third planetary gearset, and the fourth planetary gearset is a simple planetary gearset. Each of the plurality of selective couplers has an engaged configuration and a disengaged configuration. The plurality of selective couplers includes a first number of clutches and a second number of brakes. The input member is fixedly coupled to the ring gear of the first planetary gearset. The output member is fixedly coupled to the planet carrier of the third planetary gearset and the planet carrier of the fourth planetary gearset. 
     According to another exemplary embodiment of the present disclosure, a transmission is provided. The transmission comprising at least one stationary member; an input member; a plurality of planetary gearsets operatively coupled to the input member; a plurality of selective couplers operatively coupled to the plurality of planetary gearsets; and an output member operatively coupled to the input member through the plurality of planetary gearsets. Each planetary gearset of the plurality of planetary gearsets includes a sun gear, a plurality of planet gears operatively coupled to the sun gear, a planet carrier operatively coupled to the plurality of planet gears, and a ring gear operatively coupled to the plurality of planet gears. The plurality of planetary gearsets includes a first planetary gearset, a second planetary gearset, a third planetary gearset, and a fourth planetary gearset. Each of the plurality of selective couplers has an engaged configuration and a disengaged configuration. The plurality of selective couplers includes a first number of clutches and a second number of brakes, the first number being equal to the second number. The input member is fixedly coupled to the ring gear of the first planetary gearset. The output member is fixedly coupled to the planet carrier of the third planetary gearset and the planet carrier of the fourth planetary gearset. 
     According to yet another exemplary embodiment of the present disclosure, a transmission is provided. The transmission comprising at least one stationary member; an input member rotatable relative to the at least one stationary member; a plurality of planetary gearsets operatively coupled to the input member; and an output member operatively coupled to the input member through the plurality of planetary gearsets and rotatable relative to the at least one stationary member. Each of the plurality of planetary gearsets includes a first gearset component, a second gearset component, and a third gearset component. The plurality of planetary gearsets includes a first planetary gearset, a second planetary gearset, a third planetary gearset, and a fourth planetary gearset. The input member is fixedly coupled to the third gearset component of the first planetary gearset. The output member is fixedly coupled to the second gearset component of the third planetary gearset and the second gearset component of the fourth planetary gearset. The transmission further comprising a first interconnector which fixedly couples the first gearset component of the first planetary gearset and the first gearset component of the fourth planetary gearset together; a second interconnector which fixedly couples the second gearset component of the first planetary gearset to the second gearset component of the second planetary gearset; a third interconnector which fixedly couples the first gearset component of the second planetary gearset to the third gearset component of the third planetary gearset; and a plurality of selective couplers. The plurality of selective couplers includes a first selective coupler which, when engaged, fixedly couples the second gearset component of the first planetary gearset and the second gearset component of the second planetary gearset to the at least one stationary member; a second selective coupler which, when engaged, fixedly couples the third gearset component of the fourth planetary gearset to the at least one stationary member; a third selective coupler which, when engaged, fixedly couples the first gearset component of the second planetary gearset and the third gearset component of the third planetary gearset to the at least one stationary member; a fourth selective coupler which, when engaged, fixedly couples the first gearset component of the third planetary gearset to the first gearset component of the fourth planetary gearset and the first gearset component of the first planetary gearset; a fifth selective coupler which, when engaged, fixedly couples the third gearset component of the second planetary gearset to the first gearset component of the fourth planetary gearset and the first gearset component of the first planetary gearset; and a sixth selective coupler which, when engaged, fixedly couples the second gearset component of the first planetary gearset and the second gearset component of the second planetary gearset to the first gearset component of the third planetary gearset. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above-mentioned and other features and advantages of this disclosure, and the manner of attaining them, will become more apparent and will be better understood by reference to the following description of exemplary embodiments taken in conjunction with the accompanying drawings, wherein: 
         FIG. 1  is a diagrammatic view of an exemplary multi-speed transmission including four planetary gearsets and six selective couplers; and 
         FIG. 2  is a truth table illustrating the selective engagement of the six selective couplers of  FIG. 1  to provide ten forward gear or speed ratios and a reverse gear or speed ratio of the multi-speed transmission of  FIG. 1 . 
     
    
    
     Corresponding reference characters indicate corresponding parts throughout the several views. The exemplification set out herein illustrates an exemplary embodiment of the invention and such exemplification is not to be construed as limiting the scope of the invention in any manner. 
     DETAILED DESCRIPTION 
     For the purposes of promoting an understanding of the principles of the present disclosure, reference is now made to the embodiment illustrated in the drawings, which is described below. The embodiments disclosed below are not intended to be exhaustive or limit the present disclosure to the precise form disclosed in the following detailed description. Rather, the embodiments are chosen and described so that others skilled in the art may utilize its teachings. Therefore, no limitation of the scope of the present disclosure is thereby intended. Corresponding reference characters indicate corresponding parts throughout the several views. 
     In the disclosed transmission embodiments, selective couplers are disclosed. A selective coupler is a device which may be actuated to fixedly couple two or more components together. A selective coupler fixedly couples two or more components to rotate together as a unit when the selective coupler is in an engaged configuration. Further, the two or more components may be rotatable relative to each other when the selective coupler is in a disengaged configuration. The terms “couples”, “coupled”, “coupler” and variations thereof are used to include both arrangements wherein the two or more components are in direct physical contact and arrangements wherein the two or more components are not in direct contact with each other (e.g., the components are “coupled” via at least a third component), but yet still cooperate or interact with each other. 
     A first exemplary selective coupler is a clutch. A clutch couples two or more rotating components to one another so that the two or more rotating components rotate together as a unit in an engaged configuration and permits relative rotation between the two or more rotating components in the disengaged position. Exemplary clutches may be shiftable friction-locked multi-disk clutches, shiftable form-locking claw or conical clutches, wet clutches, or any other known form of a clutch. 
     A second exemplary selective coupler is a brake. A brake couples one or more rotatable components to a stationary component to hold the one or more rotatable components stationary relative to the stationary component in the engaged configuration and permits rotation of the one or more components relative to the stationary component in the disengaged configuration. Exemplary brakes may be configured as shiftable-friction-locked disk brakes, shiftable friction-locked band brakes, shiftable form-locking claw or conical brakes, or any other known form of a brake. 
     Selective couplers may be actively controlled devices or passive devices. Exemplary actively controlled devices include hydraulically actuated clutch or brake elements and electrically actuated clutch or brake elements. Additional details regarding systems and methods for controlling selective couplers are disclosed in the above-incorporated US Published Patent Application No. 2016/0047440. 
     In addition to coupling through selective couplers, various components of the disclosed transmission embodiments may be fixedly coupled together continuously throughout the operation of the disclosed transmissions. Components may be fixedly coupled together either permanently or removably. Components may be fixedly coupled together through spline connections, press fitting, fasteners, welding, machined or formed functional portions of a unitary piece, or other suitable methods of connecting components. 
     The disclosed transmission embodiments include a plurality of planetary gearsets. Each planetary gearset includes at least four components: a sun gear; a ring gear; a plurality of planet gears; and a carrier that is rotatably coupled to and carries the planet gears. In the case of a simple planetary gearset, the teeth of the sun gear are intermeshed with the teeth of the planet gears which are in turn intermeshed with the teeth of the ring gear. Each of these components may also be referred to as a gearset component. It will be apparent to one of skill in the art that some planetary gearsets may include further components than those explicitly identified. For example, one or more of the planetary gearsets may include two sets of planet gears. A first set of planet gears may intermesh with the sun gear while the second set of planet gears intermesh with the first set of planet gears and the ring gear. Both sets of planet gears are carried by the planet carrier. 
     One or more rotating components, such as shafts, drums, and other components, may be collectively referred to as an interconnector when the one or more components are fixedly coupled together. Interconnectors may further be fixedly coupled to one or more gearset components and/or one or more selective couplers. 
     An input member of the disclosed transmission embodiments is rotated by a prime mover. Exemplary prime movers include internal combustion engines, electric motors, hybrid power systems, and other suitable power systems. In one embodiment, the prime mover indirectly rotates the input member through a clutch and/or a torque converter. An output member of the disclosed transmission embodiments provides rotational power to one or more working components. Exemplary working components include one or more drive wheels of a motor vehicle, a power take-off shaft, and other suitable devices. The output member is rotated based on the interconnections of the gearset components and the selective couplers of the transmission. By changing the interconnections of the gearset components and the selective couplers, a rotation speed of the output member may be varied from a rotation speed of the input member. 
     The disclosed transmission embodiment is capable of transferring torque from the input member to the output member and rotating the output member in at least nine forward gear or speed ratios relative to the input member, illustratively ten forward gear or speed ratios, and one reverse gear or speed ratio wherein the rotation direction of the output member is reversed relative to its rotation direction for the at least nine forward ratios. Exemplary gear ratios that may be obtained using the embodiments of the present disclosure are disclosed herein. Of course, other gear ratios are achievable depending on the characteristics of the gearsets utilized. Exemplary characteristics include respective gear diameters, the number of gear teeth, and the configurations of the various gears. 
       FIG. 1  is a diagrammatic representation of a multi-speed transmission  100 . Multi-speed transmission  100  includes an input member  102  and an output member  104 . Each of input member  102  and output member  104  is rotatable relative to at least one stationary member  106 . An exemplary input member  102  is an input shaft or other suitable rotatable component. An exemplary output member  104  is an output shaft or other suitable rotatable component. An exemplary stationary member  106  is a housing of multi-speed transmission  100 . The housing may include several components coupled together. 
     Multi-speed transmission  100  includes a plurality of planetary gearsets, illustratively a first planetary gearset  108 , a second planetary gearset  110 , a third planetary gearset  112 , and a fourth planetary gearset  114 . In one embodiment, additional planetary gearsets may be included. Further, although first planetary gearset  108 , second planetary gearset  110 , third planetary gearset  112 , and fourth planetary gearset  114  are illustrated as simple planetary gearsets, it is contemplated that compound planetary gearsets may be included in some embodiments. 
     In one embodiment, multi-speed transmission  100  is arranged as illustrated in  FIG. 1 , with first planetary gearset  108  positioned between a first location or end  116  at which input member  102  enters stationary member  106  and second planetary gearset  110 , second planetary gearset  110  is positioned between first planetary gearset  108  and third planetary gearset  112 , third planetary gearset  112  is positioned between second planetary gearset  110  and fourth planetary gearset  114 , and fourth planetary gearset  114  is positioned between third planetary gearset  112  and a second location or end  118  at which output member  104  exits stationary member  106 . In alternative embodiments, first planetary gearset  108 , second planetary gearset  110 , third planetary gearset  112 , and fourth planetary gearset  114  are arranged in any order relative to location  116  and location  118 . In the illustrated embodiment of  FIG. 1 , each of first planetary gearset  108 , second planetary gearset  110 , third planetary gearset  112 , and fourth planetary gearset  114  are axially aligned. In one example, input member  102  and output member  104  are also axially aligned with first planetary gearset  108 , second planetary gearset  110 , third planetary gearset  112 , and fourth planetary gearset  114 . In alternative embodiments, one or more of input member  102 , output member  104 , first planetary gearset  108 , second planetary gearset  110 , third planetary gearset  112 , and fourth planetary gearset  114  are offset and not axially aligned with the remainder. 
     First planetary gearset  108  includes a sun gear  120 , a planet carrier  122  supporting a plurality of planet gears  124 , and a ring gear  126 . Second planetary gearset  110  includes a sun gear  130 , a planet carrier  132  supporting a plurality of planet gears  134 , and a ring gear  136 . Third planetary gearset  112  includes a sun gear  140 , a planet carrier  142  supporting a plurality of planet gears  144 , and a ring gear  146 . Fourth planetary gearset  114  includes a sun gear  150 , a planet carrier  152  supporting a plurality of planet gears  154 , and a ring gear  156 . 
     Multi-speed transmission  100  further includes a plurality of selective couplers, illustratively a first selective coupler  162 , a second selective coupler  164 , a third selective coupler  166 , a fourth selective coupler  168 , a fifth selective coupler  170 , and a sixth selective coupler  172 . In the illustrated embodiment, first selective coupler  162 , second selective coupler  164 , and third selective coupler  166  are brakes and fourth selective coupler  168 , fifth selective coupler  170 , and sixth selective coupler  172  are clutches. The axial locations of the clutches and brakes relative to the plurality of planetary gearsets may be altered from the illustrated axial locations. 
     Multi-speed transmission  100  includes several components that are illustratively shown as being fixedly coupled together. Input member  102  is fixedly coupled to ring gear  126  of first planetary gearset  108 . Output member  104  is fixedly coupled to planet carrier  152  of fourth planetary gearset  114  and planet carrier  142  of third planetary gearset  112 . Sun gear  120  of first planetary gearset  108  is fixedly coupled to sun gear  150  of fourth planetary gearset  114 , fourth selective coupler  168 , and fifth selective coupler  170 . Planet carrier  122  of first planetary gearset  108  is fixedly coupled to planet carrier  132  of second planetary gearset  110 , first selective coupler  162 , and sixth selective coupler  172 . Sun gear  130  of second planetary gearset  110  is fixedly coupled to ring gear  146  of third planetary gearset  112  and third selective coupler  166 . Ring gear  156  of fourth planetary gearset  114  is fixedly coupled to second selective coupler  164 . Sun gear  140  of third planetary gearset  112  is fixedly coupled to fourth selective coupler  168  and sixth selective coupler  172 . Ring gear  136  of second planetary gearset  110  is fixedly coupled to fifth selective coupler  170 . In alternative embodiments, one or more of the components fixedly coupled together are selectively coupled together through one or more selective couplers. 
     Multi-speed transmission  100  may be described as having eight interconnectors. Input member  102  is a first interconnector that both provides input torque to multi-speed transmission  100  and is fixedly coupled to ring gear  126  of first planetary gearset  108 . Output member  104  is a second interconnector that both provides output torque from multi-speed transmission  100  and fixedly couples planet carrier  152  of fourth planetary gearset  114  to planet carrier  142  of third planetary gearset  112 . A third interconnector  180  fixedly couples sun gear  120  of first planetary gearset  108 , sun gear  150  of fourth planetary gearset  114 , fourth selective coupler  168 , and fifth selective coupler  170  together. A fourth interconnector  182  fixedly couples planet carrier  122  of first planetary gearset  108 , planet carrier  132  of second planetary gearset  110 , first selective coupler  162 , and sixth selective coupler  172  together. A fifth interconnector  184  fixedly couples sun gear  130  of second planetary gearset  110 , ring gear  146  of third planetary gearset  112 , and third selective coupler  166  together. A sixth interconnector  186  fixedly couples ring gear  156  of fourth planetary gearset  114  to second selective coupler  164 . A seventh interconnector  188  fixedly couples sun gear  140  of third planetary gearset  112 , fourth selective coupler  168 , and sixth selective coupler  172  together. An eighth interconnector  190  fixedly couples ring gear  136  of second planetary gearset  110  to fifth selective coupler  170 . 
     Multi-speed transmission  100  further includes several components that are illustratively shown as being selectively coupled together through selective couplers. First selective coupler  162 , when engaged, fixedly couples planet carrier  122  of first planetary gearset  108  and planet carrier  132  of second planetary gearset  110  to stationary member  106 . When first selective coupler  162  is disengaged, planet carrier  122  of first planetary gearset  108  and planet carrier  132  of second planetary gearset  110  may rotate relative to stationary member  106 . 
     Second selective coupler  164 , when engaged, fixedly couples ring gear  156  of fourth planetary gearset  114  to stationary member  106 . When second selective coupler  164  is disengaged, ring gear  156  of fourth planetary gearset  114  may rotate relative to stationary member  106 . 
     Third selective coupler  166 , when engaged, fixedly couples sun gear  130  of second planetary gearset  110  and ring gear  146  of third planetary gearset  112  to stationary member  106 . When third selective coupler  166  is disengaged, sun gear  130  of second planetary gearset  110  and ring gear  146  of third planetary gearset  112  may rotate relative to stationary member  106 . 
     Fourth selective coupler  168 , when engaged, fixedly couples sun gear  140  of third planetary gearset  112  to sun gear  150  of fourth planetary gearset  114  and sun gear  120  of first planetary gearset  108 . When fourth selective coupler  168  is disengaged, sun gear  140  of third planetary gearset  112  may rotate relative to sun gear  150  of fourth planetary gearset  114  and sun gear  120  of first planetary gearset  108 . 
     Fifth selective coupler  170 , when engaged, fixedly couples ring gear  136  of second planetary gearset  110  to sun gear  150  of fourth planetary gearset  114  and sun gear  120  of first planetary gearset  108 . When fifth selective coupler  170  is disengaged, ring gear  136  of second planetary gearset  110  may rotate relative to sun gear  150  of fourth planetary gearset  114  and sun gear  120  of first planetary gearset  108 . 
     Sixth selective coupler  172 , when engaged, fixedly couples sun gear  140  of third planetary gearset  112  to planet carrier  132  of second planetary gearset  110  and planet carrier  122  of first planetary gearset  108 . When sixth selective coupler  172  is disengaged, sun gear  140  of third planetary gearset  112  may rotate relative to planet carrier  132  of second planetary gearset  110  and planet carrier  122  of first planetary gearset  108 . 
     By engaging various combinations of first selective coupler  162 , second selective coupler  164 , third selective coupler  166 , fourth selective coupler  168 , fifth selective coupler  170 , and sixth selective coupler  172 , additional components of multi-speed transmission  100  may be fixedly coupled together. 
     The plurality of planetary gearsets and the plurality of selective couplers of multi-speed transmission  100  may be interconnected in various arrangements to provide torque from input member  102  to output member  104  in at least nine forward gear or speed ratios and at least one reverse gear or speed ratio. Referring to  FIG. 2 , an exemplary truth table  200  is shown that provides the state of each of first selective coupler  162 , second selective coupler  164 , third selective coupler  166 , fourth selective coupler  168 , fifth selective coupler  170 , and sixth selective coupler  172  for ten different forward gear or speed ratios and one reverse gear or speed ratio. Each row corresponds to a given interconnection arrangement for transmission  100 . The first column provides the gear range (reverse and 1 st -10 th  forward gears). The second column provides the gear ratio between the input member  102  and the output member  104 . The third column provides the gear step. The six rightmost columns illustrate which ones of the selective couplers  162 - 172  are engaged (“1” indicates engaged) and which ones of selective couplers  162 - 172  are disengaged (“(blank)” indicates disengaged).  FIG. 2  is only one example of any number of truth tables possible for achieving at least nine forward ratios and one reverse ratio. 
     In the example of  FIG. 2 , the illustrated reverse ratio (Rev) is achieved by having first selective coupler  162 , second selective coupler  164 , and fourth selective coupler  168  in an engaged configuration and third selective coupler  166 , fifth selective coupler  170 , and sixth selective coupler  172  in a disengaged configuration. 
     In one embodiment, to place multi-speed transmission  100  in neutral (Neu), all of first selective coupler  162 , second selective coupler  164 , third selective coupler  166 , fourth selective coupler  168 , fifth selective coupler  170 , and sixth selective coupler  172  are in the disengaged configuration. One or more of first selective coupler  162 , second selective coupler  164 , third selective coupler  166 , fourth selective coupler  168 , fifth selective coupler  170 , and sixth selective coupler  172  may remain engaged in neutral (Neu) as long as the combination of first selective coupler  162 , second selective coupler  164 , third selective coupler  166 , fourth selective coupler  168 , fifth selective coupler  170 , and sixth selective coupler  172  does not transmit torque from input member  102  to output member  104 . 
     A first forward ratio (shown as 1st) in truth table  200  of  FIG. 2  is achieved by having second selective coupler  164 , fourth selective coupler  168 , and sixth selective coupler  172  in an engaged configuration and first selective coupler  162 , third selective coupler  166 , and fifth selective coupler  170  in a disengaged configuration. 
     A second or subsequent forward ratio (shown as 2nd) in truth table  200  of  FIG. 2  is achieved by having third selective coupler  166 , fourth selective coupler  168 , and sixth selective coupler  172  in an engaged configuration and first selective coupler  162 , second selective coupler  164 , and fifth selective coupler  170  in a disengaged configuration. Therefore, when transitioning between the first forward ratio and the second forward ratio, second selective coupler  164  is placed in the disengaged configuration and third selective coupler  166  is placed in the engaged configuration. 
     A third or subsequent forward ratio (shown as 3rd) in truth table  200  of  FIG. 2  is achieved by having second selective coupler  164 , third selective coupler  166 , and sixth selective coupler  172  in an engaged configuration and first selective coupler  162 , fourth selective coupler  168 , and fifth selective coupler  170  in a disengaged configuration. Therefore, when transitioning between the second forward ratio and the third forward ratio, fourth selective coupler  168  is placed in the disengaged configuration and second selective coupler  164  is placed in the engaged configuration. 
     A fourth or subsequent forward ratio (shown as 4th) in truth table  200  of  FIG. 2  is achieved by having third selective coupler  166 , fifth selective coupler  170 , and sixth selective coupler  172  in an engaged configuration and first selective coupler  162 , second selective coupler  164 , and fourth selective coupler  168  in a disengaged configuration. Therefore, when transitioning between the third forward ratio and the fourth forward ratio, second selective coupler  164  is placed in the disengaged configuration and fifth selective coupler  170  is placed in the engaged configuration. 
     A fifth or subsequent forward ratio (shown as 5th) in truth table  200  of  FIG. 2  is achieved by having second selective coupler  164 , third selective coupler  166 , and fifth selective coupler  170  in an engaged configuration and first selective coupler  162 , fourth selective coupler  168 , and sixth selective coupler  172  in a disengaged configuration. Therefore, when transitioning between the fourth forward ratio and the fifth forward ratio, sixth selective coupler  172  is placed in the disengaged configuration and second selective coupler  164  is placed in the engaged configuration. 
     A sixth or subsequent forward ratio (shown as 6th) in truth table  200  of  FIG. 2  is achieved by having second selective coupler  164 , fourth selective coupler  168 , and fifth selective coupler  170  in an engaged configuration and first selective coupler  162 , third selective coupler  166 , and sixth selective coupler  172  in a disengaged configuration. Therefore, when transitioning between the fifth forward ratio and the sixth forward ratio, third selective coupler  166  is placed in the disengaged configuration and fourth selective coupler  168  is placed in the engaged configuration. 
     A seventh or subsequent forward ratio (shown as 7th) in truth table  200  of  FIG. 2  is achieved by having third selective coupler  166 , fourth selective coupler  168 , and fifth selective coupler  170  in an engaged configuration and first selective coupler  162 , second selective coupler  164 , and sixth selective coupler  172  in a disengaged configuration. Therefore, when transitioning between the sixth forward ratio and the seventh forward ratio, second selective coupler  164  is placed in the disengaged configuration and third selective coupler  166  is placed in the engaged configuration. 
     An eighth or subsequent forward ratio (shown as 8th) in truth table  200  of  FIG. 2  is achieved by having fourth selective coupler  168 , fifth selective coupler  170 , and sixth selective coupler  172  in an engaged configuration and first selective coupler  162 , second selective coupler  164 , and third selective coupler  166  in a disengaged configuration. Therefore, when transitioning between the seventh forward ratio and the eighth forward ratio, third selective coupler  166  is placed in the disengaged configuration and sixth selective coupler  172  is placed in the engaged configuration. 
     A ninth or subsequent forward ratio (shown as 9th) in truth table  200  of  FIG. 2  is achieved by having first selective coupler  162 , fourth selective coupler  168 , and fifth selective coupler  170  in an engaged configuration and second selective coupler  164 , third selective coupler  166 , and sixth selective coupler  172  in a disengaged configuration. Therefore, when transitioning between the eighth forward ratio and the ninth forward ratio, sixth selective coupler  172  is placed in the disengaged configuration and first selective coupler  162  is placed in the engaged configuration. 
     A tenth or subsequent forward ratio (shown as 10th) in truth table  200  of  FIG. 2  is achieved by having first selective coupler  162 , fifth selective coupler  170 , and sixth selective coupler  172  in an engaged configuration and second selective coupler  164 , third selective coupler  166 , and fourth selective coupler  168  in a disengaged configuration. Therefore, when transitioning between the ninth forward ratio and the tenth forward ratio, fourth selective coupler  168  is placed in the disengaged configuration and sixth selective coupler  172  is placed in the engaged configuration. 
     The present disclosure contemplates that downshifts follow the reverse sequence of the corresponding upshift (as described above). Further, several power-on skip-shifts that are single-transition are possible (e.g. from 1 st  up to 3 rd , from 3 rd  down to 1 st , from 3 rd  up to 5 th , and from 5 th  down to 3 rd ). 
     In the illustrated embodiment, various combinations of three of the available selective couplers are engaged for each of the illustrated forward speed ratios and reverse speed ratios. Additional forward speed ratios and reverse speed ratios are possible based on other combinations of engaged selective couplers. Although in the illustrated embodiment, each forward speed ratio and reverse speed ratio has three of the available selective couplers engaged, it is contemplated that less than three and more than three selective couplers may be engaged at the same time. 
     While this invention has been described as having exemplary designs, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.