A process for presuming a power-transmitted state in a metal belt-type continuously variable transmission, said transmission comprising a metal belt having rings and a plurality of blocks supported on said rings, a drive pulley and a driven pulley, wherein said metal belt is reeved around said drive pulley and said driven pulley, and wherein the shift ratio is controlled by changing groove widths of both said drive and driven pulleys by controlling the hydraulic pressure thereon, said process comprising the steps of:
- forming relational equations indicating relationships between:
- a speed ratio (i) between said drive and driven pulleys,
- a number (N.sub.IN) of rotations of said drive pulley,
- an input torque (T.sub.IN) to said drive pulley,
- an axial thrust (Q.sub.DR) of said drive pulley,
- an axial thrust (Q.sub.DN) of said driven pulley,
- one of an urging force (E.sub.1) between said blocks at an outlet
- of said drive pulley and an urging force (E.sub.2) between said blocks a t an inlet of said drive pulley,
- an axis-axis force (FS) between said drive pulley and said driven pulley,
- a tension (T.sub.1) of said ring at the outlet of said drive pulley,
- a tension (T.sub.2) of said ring at the inlet of said drive pulley,
- a tangent component (.mu..sub.SDR) of a friction coefficient between said ring a nd said b lock of said drive pulley, and
- a tangent component (.mu..sub.SDN) of a friction coefficient between said ring and said block of said driven pulley;
- introducing the tangent component (.mu..sub.SDR or .mu..sub.SDN) of the friction coefficient between said ring and said block of the one of said drive pulley and said driven pulley which has a smaller winding diameter, into the relational equations on the assumption that the tangent component of the friction coefficient is a predetermined value;
- and
- measuring the speed ratio (i) between said drive pulley and said driven pulley, the number (N.sub.IN) of rotations of said drive pulley, the input torque (T.sub.IN) to said drive pulley and the axial thrust (Q.sub.DN) of said driven pulley, to place them into the relational equations,
- thereby calculating the tension (T.sub.1) of said ring at the outlet of said drive pulley, the tension (T.sub.2) of said ring at the inlet of said drive pulley and one of the urging force (E.sub.1) between said blocks at the outlet of said drive pulley and the urging force (E.sub.2) between said blocks at the inlet of said drive pulley.