Disclosed herein is a rotation transmitting device which permits the transmission of rotation with a reduced play and which permits the constituents to be aligned easily. The rotation transmitting device has a transmitting member (30) which surrounds a rotating part (12) of a drive shaft (11) and a rotating part (22) of a driven shaft (21). At least either the rotating part (12) of the drive shaft (11) or the rotating part (22) of the driven shaft (21) has an external surface that comes into contact with the internal surface of the transmitting member (30) so that friction arising between the internal surface and the external surface achieves torque transmission and reception to and from the transmitting member (30).

A toroidal continuously variable transmission includes a first disc and a second disc disposed so that the first disc and the second disc are rotatable around a common rotational axis line, the first disc and the second disc facing each other; a power roller which is tiltably disposed between the first disc and the second disc; a pressing device of a loading cam type, the pressing device including a cam plate which is rotatable around the rotational axis line, and a roller unit including at least one roller sandwiched between a cam surface of the second disc and a cam surface of the cam plate; and a cam plate support supporting a back surface of the cam plate, the back surface being opposite to the cam surface of the cam plate, at a radial position conforming to a radial position of at least a portion of the roller unit.

An epicyclic traction drive transmission, including a carrier having a central axis, a sun shaft rotationally mounted within the carrier, a plurality of planet rollers mounted on the carrier, and an outer ring. Wedge rollers associated with each planet roller are located in a wedging slot defined between the ring and the planet roller. A resistance mechanism is provided so that the wedge roller's movement into the wedging slot is resisted by a force that is transferred to the carrier.

An epicyclic traction drive transmission, including a carrier having a central axis, a sun shaft rotationally mounted within the carrier, a plurality of planet rollers mounted on the carrier, and an outer ring. Wedge rollers associated with each planet roller are located in a wedging slot defined between the ring and the planet roller. A resistance mechanism is provided so that the wedge roller's movement into the wedging slot is resisted by a force that is transferred to the carrier.

A method of controlling a continuously variable electric drivetrain (CVED) including a high ratio traction drive transmission and at least one of a first motor-generator and a second motor-generator is disclosed. The method includes the steps of receiving a an output speed, determining a kinematic output speed, and determining a slip state of the high ratio traction drive transmission based on a comparison of the output speed to the kinematic output speed.

It is described a compound planetary friction drive comprising a first sun wheel (2) and planetary wheels (3), wherein said first sun wheel (2) engages said planetary wheels (3), which planetary wheels (3) are arranged with two outer parts (3b) having a first radius (r1) and a central part (3a) having a second radius (r2), wherein the second radius (r2) differs from the first radius (r1) and transition regions (3c) are provided between the outer parts (3b) and the central part (3a), and wherein an outer ring annulus (1) and a central ring annulus (5) are provided that are in driving engagement with the planetary wheels (3), wherein the outer ring annulus (1) has two parts between which, along the length of the planetary wheels (3), the central ring annulus (5) is disposed, wherein the first sun wheel (2) is in frictional engagement with the outer parts (3b) of the planetary wheels (3), said outer parts (3b) of the planetary wheels (3) are in frictional engagement with the parts of the outer ring annulus (1) and the central ring annulus (5) is in frictional engagement with the central part (3a) of the planetary wheels (3), wherein the planetary wheels (3) are both hollow and compressible uninterruptedly along their entire length spanning the outer parts (3b), the transition regions (3c) and the central part (3a).

It is described a compound planetary friction drive comprising a first sun wheel (2) and planetary wheels (3), wherein said first sun wheel (2) engages said planetary wheels (3), which planetary wheels (3) are arranged with two outer parts (3b) having a first radius (r1) and a central part (3a) having a second radius (r2), wherein the second radius (r2) differs from the first radius (r1) and transition regions (3c) are provided between the outer parts (3b) and the central part (3a), and wherein an outer ring annulus (1) and a central ring annulus (5) are provided that are in driving engagement with the planetary wheels (3), wherein the outer ring annulus (1) has two parts between which, along the length of the planetary wheels (3), the central ring annulus (5) is disposed, wherein the first sun wheel (2) is in frictional engagement with the outer parts (3b) of the planetary wheels (3), said outer parts (3b) of the planetary wheels (3) are in frictional engagement with the parts of the outer ring annulus (1) and the central ring annulus (5) is in frictional engagement with the central part (3a) of the planetary wheels (3), wherein the planetary wheels (3) are both hollow and compressible uninterruptedly along their entire length spanning the outer parts (3b), the transition regions (3c) and the central part (3a).

It is described a compound planetary friction drive comprising a first sun wheel (2) and planetary wheels (3), wherein said first sun wheel (2) engages said planetary wheels (3), which planetary wheels (3) are arranged with two outer parts (3b) having a first radius (r1) and a central part (3a) having a second radius (r2), wherein the second radius (r2) differs from the first radius (r1) and transition regions (3c) are provided between the outer parts (3b) and the central part (3a), and wherein an outer ring annulus (1) and a central ring annulus (5) are provided that are in driving engagement with the planetary wheels (3), wherein the outer ring annulus (1) has two parts between which, along the length of the planetary wheels (3), the central ring annulus (5) is disposed, wherein the first sun wheel (2) is in frictional engagement with the outer parts (3b) of the planetary wheels (3), said outer parts (3b) of the planetary wheels (3) are in frictional engagement with the parts of the outer ring annulus (1) and the central ring annulus (5) is in frictional engagement with the central part (3a) of the planetary wheels (3), wherein the planetary wheels (3) are both hollow and compressible uninterruptedly along their entire length spanning the outer parts (3b), the transition regions (3c) and the central part (3a).

It is described a compound planetary friction drive comprising a first sun wheel (2) and planetary wheels (3), wherein said first sun wheel (2) engages said planetary wheels (3), which planetary wheels (3) are arranged with two outer parts (3b) having a first radius (r1) and a central part (3a) having a second radius (r2), wherein the second radius (r2) differs from the first radius (r1) and transition regions (3c) are provided between the outer parts (3b) and the central part (3a), and wherein an outer ring annulus (1) and a central ring annulus (5) are provided that are in driving engagement with the planetary wheels (3), wherein the outer ring annulus (1) has two parts between which, along the length of the planetary wheels (3), the central ring annulus (5) is disposed, wherein the first sun wheel (2) is in frictional engagement with the outer parts (3b) of the planetary wheels (3), said outer parts (3b) of the planetary wheels (3) are in frictional engagement with the parts of the outer ring annulus (1) and the central ring annulus (5) is in frictional engagement with the central part (3a) of the planetary wheels (3), wherein the planetary wheels (3) are both hollow and compressible uninterruptedly along their entire length spanning the outer parts (3b), the transition regions (3c) and the central part (3a).

An epicyclic traction drive transmission, including a carrier 7 having a central axis, a sun shaft 9 rotationally mounted within carrier 7 and positioned in the central axis, a plurality of planet rollers 4 mounted on carrier 7 and arranged to rotate on respective angularly equidistant axles 5, and rotationally engage the sun shaft 9, and an outer ring 1. A wedge roller 2,3 associated with each planet roller 4 is free to translate relative to carrier 7; and engages outer ring 1 and respective planetary roller 4 with a frictional or traction coefficient , and the wedge roller 2,3 defining a wedging angle , such that tan /2 is less than . In one form there are two wedge rollers 2,3 for each planet roller, allowing for a wedging action in either direction of rotation.