Patent ID: 11892060
Assignee: NSK LTD.
Field: Mechanical elements (Mechanical engineering)
Classification: CPC F | IPC F

Claim 0:
1. A frictional roller reducer including:
a sun roller;
a ring roller arranged coaxially with the sun roller around the sun roller;
a plurality of intermediate rollers respectively having a rolling surface on an outer circumferential surface thereof, the rolling surfaces of the plurality of intermediate rollers coming in rolling contact with the sun roller and the ring roller;
one roller of the sun roller or the ring roller having a pair of roller elements supported so as to be able to relatively displace in an axial direction, the pair of roller elements including inclined surface portions on a circumferential surface of the one roller coming in rolling contact with the rolling surfaces, the inclined surface portions inclined in directions going toward the intermediate rollers in a radial direction as going away from each other in the axial direction;
a pressing device pressing the pair of roller elements in directions going closer to each other, and
an elastic member arranged between and directly acting on the pair of roller elements, the elastic member urging the pair of roller elements in directions going away from the rolling surface of the intermediate rollers,
wherein the pressing device has one roller element of the pair of roller elements and a cam disk supported so as to be able to relatively rotate with respect to the one roller element and to relatively displace in the axial direction, and is configured by a loading cam device which expands a distance between the one roller element and the cam disk based on a rotation of the one roller element as torque is transmitted between the sun roller and the ring roller, and presses the pair of roller elements in directions going closer to each other, and
a gap is provided between the elastic member and at least one roller element of the pair of roller elements in an initial state before the pressing device exerts pressing force.