Patent ID: 6602160
Filing Date: 2003-08-05
Classification: F16H,Y02T,Y10T

Abstract:
A device for hydraulically controlling a continuously variable transmission comprising:a continuously variable transmission of the V-belt type connected to the output side of an engine; rotation sensors for detecting the input and output rotational speeds of said continuously variable transmission; hydraulic pressure sensors for detecting first and second real hydraulic pressures for the first and second pulleys in said continuously variable transmission; and a controller that receives operation conditions of said engine, the input and output rotational speeds of said continuously variable transmission, and the first and second real hydraulic pressures of the first and second pulleys in said continuously variable transmission, and adjusts the hydraulic pressures of said first and second pulleys; wherein said controller comprises: a belt slip detector unit which forms a slip detection signal when a slipping state of said V-belt is detected; and a belt slip suppressing unit which executes a correction processing for suppressing the slip of the V-belt in response to said slip detection signal, wherein said controller further comprises: a real transmission gear ratio operation unit for operating upon a real transmission gear ratio of said continuously variable transmission based upon said input and output rotational speeds; and a virtual transmission gear ratio operation unit for operating upon a virtual transmission gear ratio of said continuously variable transmission based upon said real transmission gear ratio; wherein said belt slip detector unit forms said slip detection signal based upon the comparison of said real transmission gear ratio with said virtual transmission gear ratio; wherein said belt slip detector unit forms said slip detection signal when a difference in the transmission gear ratio between said real transmission gear ratio and said virtual transmission gear ratio, becomes larger than a second predetermined amount in the direction of a second polarity opposite to the direction of a first polarity within a predetermined period of time from a moment when the difference in the transmission gears ratio became larger than a first predetermined amount in the direction of the first polarity.