Drive roller control for toric-drive transmission

Abstract

A continuously variable transmission, which comprises a drive race for receiving power input, a driven race for transmitting power output and a set of rollers between the races. Each roller in the set is capable of rotating to transfer motion from the drive race to the driven race, is capable of tilting about a first tilt axis to vary a ratio of the continuously variable transmission, and is capable of tilting about a second tilt axis different from the first tilt axis. The transmission further comprises a ratio change actuator acting on each roller of the set for tilting the roller about its second tilt axis, a tilt of the roller about its second tilt axis inducing a reaction force on the roller tending to tilt the roller about its first tilt axis and thus provoke a ratio change. The transmission also comprises a synchronization member coupling the rollers, when a tilting movement is imparted to the rollers about their respective first tilt axes, the synchronization member constraining the rollers to tilt in unison about the respective first tilt axes to produce a coordinated ratio change.

1 . A continuously variable transmission, comprising: 
 a. a drive race for receiving power input:    b. a driven race for transmitting power output;    c. a set of rollers between the races:    d. each roller in the set: 
 i. capable of rotating to transfer motion from the drive race to the driven race;  
 ii. capable of tilting about a first tilt axis to vary a ratio of the continuously variable transmission;  
 iii. capable of tilting about a second tilt axis different from the first tilt axis;  
   e. a ratio change actuator acting on each roller of the set for tilting the roller about its second tilt axis, a tilt of the roller about its second tilt axis inducing a reaction force on the roller tending to tilt the roller about its first tilt axis and thus provoke a ratio change;    f. a synchronization member coupling the rollers, when a tilting movement is imparted to the rollers about their respective first tilt axes, the synchronization member constraining the rollers to tilt in unison about the respective first tilt axes to produce a coordinated ratio change.    
   
   
       2 . A continuously variable transmission as defined in  claim 1 , wherein the continuously variable transmission is of the toroidal type.  
   
   
       3 . A continuously variable transmission as defined in  claim 2 , wherein the drive race and the driven race rotate about a common axis, the first tilt axis of each roller being generally perpendicular to the common axis.  
   
   
       4 . A continuously variable transmission as defined in  claim 3 , wherein the second told axis of each roller is non-parallel to the first tilt axis of the roller.  
   
   
       5 . A continuously variable transmission as defined in  claim 4 , wherein the second tilt axis of each roller is generally perpendicular to the first tilt axis of the roller.  
   
   
       6 . A continuously variable transmission as defined in  claim 5 , wherein the second tilt axis of each roller is generally parallel to the common axis.  
   
   
       7 . A continuously variable transmission as defined in  claim 6 , wherein the ratio change actuator engages each roller, the ratio change actuator being angularly moveable about the common axis such as to impart a tilting movement to each roller about its second axis.  
   
   
       8 . A continuously variable transmission as defined in  claim 7 , wherein the ratio change actuator includes a plurality of guides in which the rollers are engaged, each guide defining a path of travel for the respective roller with relation to the ratio change actuator, the path of travel permitting a reaction movement of the roller to occur in response to the tilting movement of the roller about its second axis, caused by the angular movement of the ratio change actuator.  
   
   
       9 . A continuously variable transmission as defined in  claim 8 , wherein the path of travel is oriented such that as the roller follows the path of travel it tilts about its first and second axes.  
   
   
       10 . A continuously variable transmission as defined in  claim 9 , wherein the path extends generally obliquely with relation to the common axis.  
   
   
       11 . A continuously variable transmission as defined in  claim 8 , wherein the ratio change actuator is sleeve-shaped.  
   
   
       12 . A continuously variable transmission as defined in  claim 6 , wherein the synchronization member is capable to move with relation to the ratio change actuator along the common axis.  
   
   
       13 . A continuously variable transmission as defined in  claim 12 , wherein the synchronization member is movable angularly about the common axis.  
   
   
       14 . A continuously variable transmission as defined in  claim 13 , wherein the synchronization member is movable angularly in unison with the ratio change actuator about the common axis.  
   
   
       15 . A continuously variable transmission as defined in  claim 14 , wherein the synchronization member is sleeve-shaped.  
   
   
       16 . A continuously variable transmission as defined in  claim 1 , including an actuator for causing displacement of the ratio change actuator to provoke the ratio change.  
   
   
       17 . A continuously variable transmission as defined in  claim 16 , wherein the actuator is a linear actuator.  
   
   
       18 . A continuously variable transmission, comprising: 
 a. a drive race for receiving power input, the drive race being rotatable in a first direction and in a second direction that is opposite the first direction:    b. a drive race for transmitting power output;    c. a set of rollers between the races:    d. each roller in the set: 
 i. capable of rotating to transfer motion from the drive race to the driven race;  
 ii. capable of tilting about a first tilt axis to vary a ratio of the continuously variable transmission;  
 iii. capable of tilting about a second tilt axis different from the first tilt axis;  
   e. a first ratio change actuator operable when the drive race rotates in the first direction, the first ratio change actuator acting on each roller of the set for tilting the roller about its second tilt axis, a tilt of the roller about its second tilt axis inducing a reaction force on the roller tending to tilt the roller about its first tilt axis and provoke a ratio change while the drive race turns in the first direction;    f. a second ratio change actuator operable when drive race rotates in the second direction, the second ratio change actuator acting on each roller of the set for tilting the roller about its second tilting axis, a tilt of the roller about its second tilt axis inducing a reaction force on the roller tending to tilt the roller about its first tilt axis and provoke a ratio change while the drive race turns in the second direction.