Disclosed is an adjustable ring shim for a planetary traction drive designed for a driven turbocharger on an engine. The adjustable ring shim has two parts that interface through a ramp feature to provide an ability to vary the overall width of the ring roller assembly of the planetary traction drive. This adjustability in the width of the ring roller allows for setting a desired preload force on the traction surfaces of the traction drive during assembly, even with variation in manufacturing of the different parts of the traction drive.

Disclosed is an adjustable ring shim for a planetary traction drive designed for a driven turbocharger on an engine. The adjustable ring shim has two parts that interface through a ramp feature to provide an ability to vary the overall width of the ring roller assembly of the planetary traction drive. This adjustability in the width of the ring roller allows for setting a desired preload force on the traction surfaces of the traction drive during assembly, even with variation in manufacturing of the different parts of the traction drive.

A power transmission roller assembly is provided which includes a roller body to be brought into abutment with the driving roller and the driven roller; a pivot shaft fixed to a vehicle body; a pivot arm provided radially inside of the roller body, and pivotally mounted on the pivot shaft; a roller support bearing rotatably supporting the roller body; and a pair of biasing members provided on the pivot arm. The pair of biasing members bias the roller support bearing to a predetermined position between the driving and driven rollers where the abutment forces between the roller body and the driving and driven rollers balance with each other.

An electric drive includes a motor and a transmission for transferring torque from the motor to a tool. The transmission includes a plurality of planetary rollers which are driven by a rotary shaft of the motor, and an output ring which is connectable to the tool, and which is driven by the planetary rollers. The transmission further includes a roller casing which is secured to a housing of the motor, and which supports parallel planetary shafts upon which the planetary rollers are mounted for rotation relative to the roller casing, and a bearing having an inner race which engages the roller casing, and an outer race which engages the inner periphery of the output ring.

An electric drive includes a motor and a transmission for transferring torque from the motor to a tool. The transmission includes a plurality of planetary rollers which are driven by a rotary shaft of the motor, and an output ring which is connectable to the tool, and which is driven by the planetary rollers. The transmission further includes a roller casing which is secured to a housing of the motor, and which supports parallel planetary shafts upon which the planetary rollers are mounted for rotation relative to the roller casing, and a bearing having an inner race which engages the roller casing, and an outer race which engages the inner periphery of the output ring.

A prime mover includes a stator fixed to the housing and a rotor rotatable relative to the stator. The prime mover outputs torque by being supplied with electric power. A speed reducer reduces the torque of the prime mover and outputs the reduced torque. A rotational translation unit includes a rotation portion that rotates relative to the housing upon receiving the torque from the speed reducer, and a translation portion that moves relative to the housing in an axial direction. A clutch allows torque transmission in an engaged state, and interrupts the torque transmission in a disengaged state. A state changing unit changes the state of the clutch by receiving a force along the axial direction from the translation portion. Cogging torque generated between the rotor and the stator is set to such a magnitude that the rotor is stoppable at any rotation position relative to the stator.

A sun gear of a speed reducer is provided coaxially with and integrally rotatably with a rotor of a prime mover. Multiple planetary gears are disposed in a circumferential direction of the sun gear, and are capable of revolving in the circumferential direction of the sun gear while rotating in a state of meshing with the sun gear. A carrier rotatably supports the planetary gears, and is rotatable relative to the sun gear. A first ring gear is fixed to a housing, and has a first ring gear tooth portion capable of meshing with the planetary gears. A second ring gear is rotatable integrally with a rotation portion, and has a second ring gear tooth portion capable of meshing with the planetary gears. The second ring gear tooth portion is different in number of teeth from the first ring gear tooth portion.

A state changing unit is provided radially outward of a translation portion and movable in an axial direction relative to the translation portion. The state changing unit is in contact with or separated from the clutch. The state changing unit receives a force in the axial direction from the translation portion such that the state changing unit is pressed against the clutch. The state changing unit is capable of changing a state of the clutch to an engaged state or a disengaged state according to a position of the translation portion in the axial direction relative to the housing. A movement restriction portion is provided on the translation portion and located between the state changing unit and the clutch. The movement restriction portion contacts the state changing unit and restricts movement of the state changing unit relative to the translation portion toward the clutch.

A rotational translation unit includes a rotation portion that rotates relative to a housing upon receiving an input of torque output from a speed reducer, and a translation portion that moves relative to the housing in an axial direction according to rotation of the rotation portion relative to the housing. A clutch is provided between a first transmission portion and a second transmission portion that are rotatable relative to the housing, and the clutch allows transmission of the torque between the first transmission portion and the second transmission portion in an engaged state of the clutch, and interrupts the transmission of the torque between the first transmission portion and the second transmission portion in a disengaged state of the clutch. A return spring is capable of urging the rotational translation unit in a direction away from the clutch relative to the housing.

A prime mover includes a stator fixed to the housing and a rotor rotatable relative to the stator. The prime mover outputs torque by being supplied with electric power. A speed reducer reduces the torque of the prime mover and outputs the reduced torque. A rotational translation unit includes a rotation portion that rotates relative to the housing upon receiving the torque from the speed reducer, and a translation portion that moves relative to the housing in an axial direction. A clutch allows torque transmission in an engaged state, and interrupts the torque transmission in a disengaged state. A state changing unit changes the state of the clutch by receiving a force along the axial direction from the translation portion. Cogging torque generated between the rotor and the stator is set to such a magnitude that the rotor is stoppable at any rotation position relative to the stator.