| 摘要 |
<p>Provided is a controller and a control method of a belt type continuously variable transmission wherein significant slip of a belt can be prevented during belt slip control when an estimated precision of belt slip state is low while ensuring reduction in drive energy consumption due to lowering of belt friction when the estimated precision of belt slip state is high. A controller of a belt type continuously variable transmission has a primary pulley (42), a secondary pulley (43), and a belt (44) and controls speed change ratio based on the ratio of winding diameter of the belt (44) around the pulley by controlling the primary oil pressure and the secondary oil pressure.  A belt type continuously variable transmission (4) comprises a belt slip control means (step S3) for performing such control as to oscillate the secondary oil pressure, estimate the belt slip state by monitoring the phase difference between an oscillation component included in the actual secondary oil pressure and an oscillation component included in the actual speed change ratio, and then reduce the actual secondary oil pressure to keep a predetermined belt slip state, and a belt slip control permission judgment means (step S2) for permitting belt slip control when a speed change rate, i.e. a variation rate of speed change ratio, is less than a predetermined value.</p> |
