Patent ID: 6409625
Filing Date: 2002-06-25
Classification: F16H

Abstract:
A controller for a toroidal continuously variable transmission of a vehicle, the transmission comprising an input disk which rotates about a rotation shaft, an output disk which rotates about the rotation shaft, a power roller gripped by the input disk and the output disk and transmitting a torque between the input disk and output disk, and a trunnion which drives the power roller in a direction perpendicular to the rotation shaft according to a differential pressure of a first oil chamber and a second oil chamber, the transmission causing a downshift when the second oil chamber is at a higher pressure than the first oil chamber, and causing an upshift when the first oil chamber is at a higher pressure than the second oil chamber, the first oil chamber being connected to a first passage and the second oil chamber being connected to a second oil passage, the controller comprising:a speed ratio control valve which controls a direction and a flowrate of oil in the first oil passage and the second oil passage; and a pressure control valve which limits a maximum differential pressure of the first oil chamber and the second oil chamber when the transmission causes a downshift smaller than a maximum differential pressure of the first oil chamber and the second oil chamber when the transmission causes an upshift.