Hydraulic control apparatus for stepless transmission

摘要

A hydraulic control apparatus is employed in a stepless transmission in which an endless belt is stretched between and wrapped around a pair of pulleys and the velocity ratio between input and output shafts is changed by varying the width of a groove defined in each of the pulleys. Hydraulic pressure supplied from a hydraulic pressure supply source is reduced to necessary levels by first and second adjusting apparatus, respectively, and then sent ot respective cylinder chambers of the pulleys. A controller controls the hydraulic pressure supply source on the basis of either one of the hydraulic pressures respectively reduced by the first and second adjusting apparatus which is higher than the other so that the supply source generates a hydraulic pressure which is sufficiently high to supply the higher hydraulic pressure, thus reducing loss of power in the hydraulic pressure supply source.