Abstract:
Devices and methods are provided herein for the transmission of power in motor vehicles. Power is transmitted in a smoother and more efficient manner by splitting torque into two or more torque paths. A continuously variable transmission is provided with a ball variator assembly having two arrays of balls, a planetary gear set coupled thereto and an arrangement of rotatable shafts with multiple gears and clutches that extend the ratio range of the variator. In some embodiments, clutches are coupled to the gear sets to enable synchronous shifting of gear modes.

Description:
BACKGROUND 
       [0001]    A driveline including a continuously variable transmission allows an operator or a control system to vary a drive ratio in a stepless manner, permitting a power source to operate at its most advantageous rotational speed. 
       SUMMARY 
       [0002]    Provided herein is a continuously variable transmission comprising: a first rotatable shaft operably coupleable to a source of rotational power; a second rotatable shaft aligned substantially coaxial to the first rotatable shaft, the first rotatable shaft and second rotatable shaft forming a main axis of the transmission; a third rotatable shaft aligned substantially parallel to the main axis; a variator assembly having a first traction ring assembly and a second traction ring assembly in contact with a first plurality of balls, each ball having a tillable axis of rotation; wherein the variator assembly is coaxial with the main axis, the first traction ring assembly is coupled to the second rotatable shaft; a first planetary gear set having a first sun gear, a first planet carrier, and a first ring gear; a second planetary gear set arranged coaxial with the main axis, the second planetary gear set having a second sun gear, a second planet carrier, and a second ring gear; wherein the second planet carrier is operably coupled to the first ring gear; wherein the first sun gear is coupled to the first rotatable shaft, and the first planet carrier is operably coupled to the second ring gear; a third planetary gear set arranged coaxial with the third rotatable shaft, the third planetary gear set having a third sun gear, a third planet carrier, and a third ring gear; wherein the third planet carrier is grounded; a forward clutch positioned coaxial with the third rotatable shaft, the forward clutch operably coupled to the third sun gear; and a reverse clutch operably coupled to the forward clutch and the third sun gear. 
         [0003]    Provided herein is a vehicle driveline comprising: a power source, a variable transmission of the types disclosed herein drivingly engaged with the power source, and a vehicle output drivingly engaged with the variable transmission. In some embodiments of the vehicle driveline, the power source is drivingly engaged with the vehicle output. 
         [0004]    Provided herein is a vehicle comprising the variable transmission of any one of the embodiments disclosed herein. 
         [0005]    Provided herein is a method comprising providing a variable transmission of any one of the embodiments disclosed herein. 
         [0006]    Provided herein is a method comprising providing a vehicle driveline having any one of the embodiments disclosed herein. 
         [0007]    Provided herein is a method comprising providing a vehicle of any embodiment disclosed herein. In some embodiments, the method includes engaging the reverse clutch to operate in a reverse mode. In some embodiments, the method includes engaging the forward clutch to operate in a forward mode. In some embodiments, the method includes engaging the forward clutch and the reverse clutch to operate in a park mode. In some embodiments, the method includes disengaging the forward clutch and the reverse clutch to operate in a neutral mode. 
         [0008]    Provided herein is a continuously variable transmission comprising: a first rotatable shaft operably coupleable to a source of rotational power; a second rotatable shaft aligned substantially coaxial to the first rotatable shaft, the first rotatable shaft and second rotatable shaft forming a main axis of the transmission; a variator assembly having a first traction ring assembly and a second traction ring assembly in contact with a first plurality of balls, each ball having a tiltable axis of rotation; wherein the variator assembly is coaxial with the main axis; a first planetary gear set having a first sun gear, a first planet carrier, and a first ring gear; a second planetary gear set arranged coaxial with the main axis, the second planetary gear set having a second sun gear, a second planet carrier, and a second ring gear; wherein the first planetary gear set is coupled to the second planetary gear set; and wherein the variator assembly is coupled to the first planetary gear set and the second planetary gear set. 
       INCORPORATION BY REFERENCE 
       [0009]    All publications, patents, and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    The novel features of the preferred embodiments are set forth with particularity in the appended claims. A better understanding of the features and advantages of the present embodiments will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the preferred embodiments are utilized, and the accompanying drawings of which: 
           [0011]      FIG. 1  is a side sectional view of a ball-type variator. 
           [0012]      FIG. 2  is a plan view of a carrier member that is used in the variator of  FIG. 1 . 
           [0013]      FIG. 3  is an illustrative view of different tilt positions of the ball-type variator of  FIG. 1 . 
           [0014]      FIG. 4  is a schematic diagram of a planetary powersplit continuously variable transmission. 
           [0015]      FIG. 5  is a table depicting operating modes of the continuously variable transmission depicted in  FIG. 4 . 
           [0016]      FIG. 6  is a table depicting a number of configurations of continuously variable transmissions having the ball-type variator of  FIG. 1  and two planetary gear sets. 
           [0017]      FIG. 7  is a schematic diagram of a planetary powersplit continuously variable transmission having two variators. 
           [0018]      FIG. 8  is a table depicting operating mode of the continuously variable transmission depicted in  FIG. 7 . 
           [0019]      FIG. 9  is a schematic diagram of a powersplit continuously variable transmission having a rear wheel drive configuration. 
       
    
    
     DETAILED DESCRIPTION 
       [0020]    The preferred embodiments will now be described with reference to the accompanying figures, wherein like numerals refer to like elements throughout. The terminology used in the descriptions below is not to be interpreted in any limited or restrictive manner simply because it is used in conjunction with detailed descriptions of certain specific embodiments. Furthermore, embodiments includes several novel features, no single one of which is solely responsible for its desirable attributes or which is essential to practicing the embodiments described. 
         [0021]    Provided herein are configurations of CVTs based on a ball type variators, also known as CVP, for continuously variable planetary. Basic concepts of a ball type Continuously Variable Transmissions are described in U.S. Pat. Nos. 8,469,856 and 8,870,711 incorporated herein by reference in their entirety. Such a CVT, adapted herein as described throughout this specification, comprises a number of balls (planets, spheres)  1 , depending on the application, two ring (disc) assemblies with a conical surface in contact with the balls, an input traction ring  2 , an output traction ring  3 , and an idler (sun) assembly  4  as shown on  FIG. 1 . The balls are mounted on tiltable axles  5 , themselves held in a carrier (stator, cage) assembly having a first carrier member  6  operably coupled to a second carrier member  7 . The first carrier member  6  rotates with respect to the second carrier member  7 , and vice versa. In some embodiments, the first carrier member  6  is substantially fixed from rotation while the second carrier member  7  is configured to rotate with respect to the first carrier member, and vice versa. In some embodiments, the first carrier member  6  is provided with a number of radial guide slots  8 . The second carrier member  7  is provided with a number of radially offset guide slots  9 , as illustrated in  FIG. 2 . The radial guide slots  8  and the radially offset guide slots  9  are adapted to guide the tiltable axles  5 . The axles  5  are adjusted to achieve a desired ratio of input speed to output speed during operation of the CVT. In some embodiments, adjustment of the axles  5  involves control of the position of the first and second carrier members to impart a tilting of the axles  5  and thereby adjusts the speed ratio of the variator. Other types of ball CVTs also exist, but are slightly different. 
         [0022]    The working principle of such a CVP of  FIG. 1  is shown on  FIG. 3 . The CVP itself works with a traction fluid. The lubricant between the ball and the conical rings acts as a solid at high pressure, transferring the power from the input ring, through the balls, to the output ring. By tilting the balls&#39; axes, the ratio is changed between input and output. When the axis is horizontal the ratio is one, illustrated in  FIG. 3 , when the axis is tilted the distance between the axis and the contact point change, modifying the overall ratio. All the balls&#39; axes are tilted at the same time with a mechanism included in the carrier and/or idler. Embodiments disclosed here are related to the control of a variator and/or a CVT using generally spherical planets each having a tiltable axis of rotation that are adjusted to achieve a desired ratio of input speed to output speed during operation. In some embodiments, adjustment of said axis of rotation involves angular misalignment of the planet axis in a first plane in order to achieve an angular adjustment of the planet axis in a second plane that is substantially perpendicular to the first plane, thereby adjusting the speed ratio of the variator. The angular misalignment in the first plane is referred to here as “skew”, “skew angle”, and/or “skew condition”. In some embodiments, a control system coordinates the use of a skew angle to generate forces between certain contacting components in the variator that will tilt the planet axis of rotation. The tilting of the planet axis of rotation adjusts the speed ratio of the variator. 
         [0023]    For description purposes, the term “radial” is used here to indicate a direction or position that is perpendicular relative to a longitudinal axis of a transmission or variator. The term “axial” as used here refers to a direction or position along an axis that is parallel to a main or longitudinal axis of a transmission or variator. For clarity and conciseness, at times similar components labeled similarly (for example, bearing  1011 A and bearing  1011 B) will be referred to collectively by a single label (for example, bearing  1011 ). 
         [0024]    As used here, the terms “operationally connected,” “operationally coupled”, “operationally linked”, “operably connected”, “operably coupled”, “operably linked,” “operably coupleable” and like terms, refer to a relationship (mechanical, linkage, coupling, etc.) between elements whereby operation of one element results in a corresponding, following, or simultaneous operation or actuation of a second element. It is noted that in using said terms to describe inventive embodiments, specific structures or mechanisms that link or couple the elements are typically described. However, unless otherwise specifically stated, when one of said terms is used, the term indicates that the actual linkage or coupling take a variety of forms, which in certain instances will be readily apparent to a person of ordinary skill in the relevant technology. 
         [0025]    It should be noted that reference herein to “traction” does not exclude applications where the dominant or exclusive mode of power transfer is through “friction.” Without attempting to establish a categorical difference between traction and friction drives here, generally these are typically understood as different regimes of power transfer. Traction drives usually involve the transfer of power between two elements by shear forces in a thin fluid layer trapped between the elements. The fluids used in these applications usually exhibit traction coefficients greater than conventional mineral oils. The traction coefficient (μ) represents the maximum available traction force which would be available at the interfaces of the contacting components and is the ratio of the maximum available drive torque per contact force. Typically, friction drives generally relate to transferring power between two elements by frictional forces between the elements. For the purposes of this disclosure, it should be understood that the CVTs described here operate in both tractive and frictional applications. For example, in the embodiment where a CVT is used for a bicycle application, the CVT operates at times as a friction drive and at other times as a traction drive, depending on the torque and speed conditions present during operation. 
         [0026]    Referring now to  FIG. 4 , in some embodiments, a continuously variable transmission (CVT)  10  is provided with a first rotatable shaft  11  adapted to receive power from a source of rotational power. In some embodiments, the CVT  10  has a second rotatable shaft  12  coaxial with the first rotatable shaft  11 . The first rotatable shaft  11  and the second rotatable shaft  12  form a main axis of the CVT  10 . The CVT  10  has a variator assembly  13  arranged coaxial with the main axis. In some embodiments, the variator assembly  13  is configured to be a CVP of the type depicted in  FIGS. 1-3 . In some embodiments, the variator assembly  13  has a first traction ring assembly (“CVPR1”)  14  and a second traction ring assembly (“CVPR2”)  15  in contact with an array of balls. In some embodiments, the CVT  10  is provided with a first planetary gear set  16  arranged coaxial with the main axis. The first planetary gear set  16  includes a first ring gear (“R1”)  17 , a first planet carrier (“C1”)  18 , and a first sun gear (“S1”)  19 . In some embodiments, the CVT  10  includes a second planetary gear set  20  arranged coaxial with the main axis. The second planetary gear set  20  has a second ring gear (“R2”)  21 , a second planet carrier (“C2”)  22 , and a second sun gear (“C3”)  23 . In some embodiments, the first rotatable shaft  11  is coupled to the first sun gear (“S1”)  19 . The first ring gear (“R1”)  17  is coupled to the second planet carrier (“C2”)  22 . The first planet carrier (“C1”)  18  is coupled to the second ring gear (“R2”)  21 . The second rotatable shaft  12  is coupled to the second sun gear (“S2”)  23  and the first traction ring assembly (“CVPR1”)  14 . The second ring gear (“R2”)  21  is coupled to the second traction ring assembly (“CVPR2”)  15 . The second rotatable shaft  12  is coupled to a first gear set  24 . 
         [0027]    Still referring to  FIG. 4 , in some embodiments, the CVT  10  is provided with a third rotatable shaft  25  aligned parallel to the main axis. The CVT  10  has a third planetary gear set  26  arranged coaxial with the third rotatable shaft  25 . The third planetary gear set  26  includes a third ring gear  27 , a third planet carrier  28 , and a third sun gear  29 . The third planet carrier  28  is grounded to a non-rotatable component of the CVT  10  such as the housing (not shown). In some embodiments, the CVT  10  includes a forward clutch  30  arranged coaxial with the third rotatable shaft  25 . In some embodiments, the forward clutch  30  is a synchronizer clutch. The forward clutch  30  is coupled to a second gear set  31 . The second gear set  31  is coupled to the first gear set  24 . In some embodiments, the CVT  10  includes a reverse clutch  32 . In some embodiments, the reverse clutch  32  is a synchronizer clutch. The reverse clutch  32  is coupled to a third gear set  33  (labeled in  FIG. 4  as “4a”, “4b”, and “4c”). The third gear set  33  is configured to transfer power to the reverse clutch  32  from the third sun gear  29 . The CVT  10  includes a final drive gear  34  operably coupled to the third rotatable shaft  25 . The third ring gear  27  is operably coupled to the final drive gear  34 . In some embodiments, the first gear set  24 , the second gear set  31 , and the third gear set  33  have two or more meshing gears configured to transfer rotational power. It should be appreciated that in some embodiments, the first gear set  24 , the second gear set  31 , and the third gear set  33  are optionally configured to be chains driving sprockets, or belts driving pulleys. In some embodiments, the final drive ( 26 ) is optionally configured to be a gear set or chain driving another axis. In some embodiments, the third rotatable shaft  25  is configured to be coaxial with the main axis as in the case for rear wheel drive applications. 
         [0028]    Typically, synchronizer mechanisms (referred to herein as “synchronizer clutch”) used in power transmissions include a well-known dog clutch integrated with a speed-matching device such as a cone-clutch. During operation of the transmission, if the dog teeth of the dog clutch make contact with a gear, and the two parts are spinning at different speeds, the teeth will fail to engage and a loud grinding sound will be heard as they clatter together. For this reason, a synchronizer mechanism or synchronizer clutch is used, which consists of a cone clutch. Before the teeth engage, the cone clutch engages first, which brings the two rotating elements to the same speed using friction. Until synchronization occurs, the teeth are prevented from making contact. It should be appreciated that the exact design of the synchronizer clutch is within a designer&#39;s choice for satisfying packaging and performance requirements. A synchronizer clutch is optionally configured to be a two position clutch having an engaged position and a neutral (or free) position. A synchronizer clutch is optionally configured to be a three position clutch having a first engaged position, a second engaged position, and a neutral position. Embodiments disclosed herein use synchronizer clutches to enable the pre-selection of gear sets by a control system (not shown) for smooth transition between operating modes of the transmission. It should be appreciated that other types of clutches are optionally implemented in place of synchronizer clutch to achieve the transmission configurations disclosed herein. 
         [0029]    Referring now to  FIG. 5 , during operation of the CVT  10 , a forward mode of operation corresponds to the selective engagement of the forward synchronizer clutch  30  and the disengagement of the reverse synchronizer clutch  32 . A reverse mode of operation corresponds to the selective engagement of the reverse synchronizer clutch  32  and the disengagement of the forward synchronizer clutch  30 . A neutral mode of operation corresponds to the disengagement of the forward synchronizer clutch  30  and disengagement of the reverse synchronizer clutch  32 . A park mode of operation corresponds to the simultaneous engagement of both the forward synchronizer clutch  30  and the reverse synchronizer clutch  32 . 
         [0030]    Turning now to  FIG. 6 , a number of continuously variable transmission architectures are configurable using a variator assembly, such as the variator assembly  13 , a first planetary gear set, such as the first planetary gear set  16 , and a second planetary gear set, such as the second planetary gear set  20 . For clarity and conciseness, the first planetary gear set is depicted as having the following components: a first ring gear (R1), a first planet carrier (C1), and a first sun gear (S1). The second planetary gear set is depicted as having the following components: a second ring gear (R2), a second planet carrier (C2), and a second sun gear (S2). A table  40  depicts a number of continuously variable transmission architectures listed in column  41  labeled “Configuration”. The table  40  has column  42  (“Input”) listing the planetary gear set component, or components, coupling to an input power source. An illustrative example of an input power source is embodied in the first rotatable shaft  11 . The table  40  has column  43  (“CVPR1”) listing the planetary gear set component, or components, coupling to the first traction ring assembly of the variator assembly, for example, the first traction ring assembly  14 . The table  40  has column  44  (“CVPR2”) listing the planetary gear set component, or components, coupling to the second traction ring assembly of the variator assembly, for example the second traction ring assembly  15 . The table  40  has a column  45  (“Output”) listing the planetary component, or components, configured to provide an output power. An illustrative example of an output power coupling is embodied in the second rotatable shaft  12 . Each row of the table  40  represents a continuously variable transmission configuration and the connections or couplings of planetary components. For example, the configuration listed as “1” represents a continuously variable transmission configuration having the first sun gear (S1) coupled to an input power source (Input), the second ring gear (R2) and the first planet carrier (C1) coupled to the first traction ring assembly (CVPR1), the first ring gear (R1) and the second planet carrier (C2) coupled to the second traction ring assembly (CVPR2), and the second sun gear (S2) configured to provide a power output (Output). It should be appreciated that the configurations depicted in table  40  are optionally provided with additional gear set, clutches, and shafts to suit desired operating characteristics. 
         [0031]    Referring now to  FIG. 7 , in some embodiments a continuously variable transmission (CVT)  50  is provided with a first rotatable shaft  51  adapted to receive power from a source of rotational power. In some embodiments, the CVT  50  has a second rotatable shaft  52  coaxial with the first rotatable shaft  51 . The first rotatable shaft  51  and the second rotatable shaft  52  form a main axis of the CVT  50 . The CVT  50  has a first variator assembly  53  arranged coaxial with the main axis. In some embodiments, the first variator assembly  53  is configured to be a CVP of the type depicted in  FIGS. 1-3 . In some embodiments, the first variator assembly  53  has a first traction ring assembly  54  and a second traction ring assembly  55  in contact with an array of balls. In some embodiments, the CVT  50  is provided with a second variator assembly  56  arranged coaxial with the main axis. The second variator assembly  56  includes a third traction ring assembly  57  and a fourth traction ring assembly  58 . In some embodiments, the third traction ring assembly  57  is coupled to the second traction ring assembly  55 . In other embodiments, the third traction ring assembly  57  and the second traction ring assembly  55  are an integral component. In some embodiments, the CVT  50  is provided with a first planetary gear set  59  arranged coaxial with the main axis. The first planetary gear set  59  includes a first ring gear (“R1”)  60 , a first planet carrier (“C1”)  61  and a first sun gear (“S1”)  62 . In some embodiments, the CVT  50  includes a second planetary gear set  63  arranged coaxial with the main axis. The second planetary gear set  63  has a second ring gear (“R2”)  64 , a second planet carrier (“C2”)  65 , and a second sun gear (“C3”)  66 . In some embodiments, the first rotatable shaft  51  is coupled to the first sun gear (“S1”)  62 . The first ring gear (“R1”)  60  is coupled to the second planet carrier (“C2”)  65 . The first planet carrier (“C1”)  61  is coupled to the second ring gear (“R2”)  64 . The second rotatable shaft  52  is coupled to the second sun gear (“S2”)  66  The second planet carrier (“C2”)  65  is coupled to the first traction ring assembly  54 . The second ring gear (“R2”)  64  is coupled to the fourth traction ring assembly  58 . The second rotatable shaft  52  is coupled to a first gear set  67 . 
         [0032]    Still referring to  FIG. 7 , in some embodiments, the CVT  50  is provided with a third rotatable shaft  68  aligned parallel to the main axis. The CVT  50  has a third planetary gear set  69  arranged coaxial with the third rotatable shaft  68 . The third planetary gear set  69  includes a third ring gear  70 , a third planet carrier  71 , and a third sun gear  72 . The third planet carrier  71  is grounded to a non-rotatable component of the CVT  50  such as the housing (not shown). In some embodiments, the CVT  50  includes a forward clutch  73  arranged coaxial with the third rotatable shaft  68 . In some embodiments, the forward clutch  73  is a synchronizer clutch. The forward clutch  73  is coupled to a second gear set  74 . The second gear set  74  is coupled to the first gear set  67 . In some embodiments, the CVT  50  includes a reverse clutch  75 . In some embodiments, the reverse clutch  75  is a synchronizer clutch. The reverse clutch  75  is coupled to a third gear set  76  (labeled in  FIG. 7  as “4a”, “4b”, and “4c”). The third gear set  76  is configured to transfer power to the reverse clutch  75  from the third sun gear  72 . The CVT  50  includes a final drive gear  77  operably coupled to the third rotatable shaft  68 . The third ring gear  70  is operably coupled to the final drive gear  77 . In some embodiments, the first gear set  67 , the second gear set  74 , and the third gear set  76  have two or more meshing gears configured to transfer rotational power. It should be appreciated that in some embodiments, the first gear set  67 , the second gear set  74 , and the third gear set  76  are optionally configured to be chains driving sprockets, or belts driving pulleys. In some embodiments, the final drive  77  is optionally configured to be a gear set or chain driving another axis. 
         [0033]    Referring now to  FIG. 8 , during operation of the CVT  50 , a forward mode of operation corresponds to the selective engagement of the forward synchronizer clutch  73  and the disengagement of the reverse synchronizer clutch  75 . A reverse mode of operation corresponds to the selective engagement of the reverse synchronizer clutch  75  and the disengagement of the forward synchronizer clutch  73 . A neutral mode of operation corresponds to the disengagement of the forward synchronizer clutch  73  and disengagement of the reverse synchronizer clutch  75 . A park mode of operation corresponds to the simultaneous engagement of both the forward synchronizer clutch  73  and the reverse synchronizer clutch  75 . 
         [0034]    Referring now to  FIG. 9 , in some embodiments, a continuously variable transmission (CVT)  150  is provided with a first rotatable shaft  151  adapted to receive power from a source of rotational power. In some embodiments, the CVT  150  has a second rotatable shaft  152  coaxial with the first rotatable shaft  151 . The first rotatable shaft  151  and the second rotatable shaft  152  form a main axis of the CVT  150 . The CVT  150  has a variator assembly  153  arranged coaxial with the main axis. In some embodiments, the variator assembly  153  is configured to be a CVP of the type depicted in  FIGS. 1-3 . In some embodiments, the variator assembly  153  has a first traction ring assembly (“CVPR1”)  154  and a second traction ring assembly (“CVPR2”)  155  in contact with an array of balls. In some embodiments, the CVT  150  is provided with a first planetary gear set  156  arranged coaxial with the main axis. The first planetary gear set  156  includes a first ring gear (“R1”)  157 , a first planet carrier (“C1”)  158 , and a first sun gear (“S1”)  159 . In some embodiments, the CVT  150  includes a second planetary gear set  160  arranged coaxial with the main axis. The second planetary gear set  160  has a second ring gear (“R2”)  161 , a second planet carrier (“C2”)  162 , and a second sun gear (“C3”)  163 . In some embodiments, the first rotatable shaft  151  is coupled to the first sun gear (“S1”)  159 . The first ring gear (“R1”)  157  is coupled to the second planet carrier (“C2”)  162 . The first planet carrier (“C1”)  158  is coupled to the second ring gear (“R2”)  161 . The second rotatable shaft  152  is coupled to the second sun gear (“S2”)  163  and the first traction ring assembly (“CVPR1”)  154 . The second ring gear (“R2”)  161  is coupled to the second traction ring assembly (“CVPR2”)  155 . The second rotatable shaft  152  is coupled to a first gear set  164 . The first gear set  164  is coupled to a third rotatable shaft  165 . The third rotatable shaft  165  is parallel to the main axis formed by the first rotatable shaft  151  and the second rotatable shaft  152 . In some embodiments, the CVT  150  includes a second gear set  166  coupled to the third rotatable shaft  165  and a first synchronizer clutch  167 . The first synchronizer clutch  167  is coupled to a fourth rotatable shaft  168 . The fourth rotatable shaft  168  is coaxial with the main axis. In some embodiments, the CVT  150  includes a reverse gear set  169  coupled to the third rotatable shaft  165  and a reverse synchronizer clutch  170 . The reverse synchronizer clutch  170  is coupled to the fourth rotatable shaft  168 . In some embodiments, the first synchronizer clutch  167  and the reverse synchronizer clutch  170  are configured as a three position synchronizer clutch. During operation of the CVT  150 , engagement of the first synchronizer clutch  167  corresponds to operation in a forward direction. Engagement of the reverse synchronizer clutch  170  corresponds to operation in a reverse direction. 
         [0035]    It should be noted that the description above has provided dimensions for certain components or subassemblies. The mentioned dimensions, or ranges of dimensions, are provided in order to comply as best as possible with certain legal requirements, such as best mode. However, the scope of the preferred embodiments described herein are to be determined solely by the language of the claims, and consequently, none of the mentioned dimensions is to be considered limiting on the inventive embodiments, except in so far as any one claim makes a specified dimension, or range of thereof, a feature of the claim. 
         [0036]    While preferred embodiments have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the preferred embodiments. It should be understood that various alternatives to the embodiments described herein may be employed in practicing the preferred embodiments. It is intended that the following claims define the scope of the preferred embodiments and that methods and structures within the scope of these claims and their equivalents be covered thereby.