Belt-type continuously variable transmission

A method for a belt-type continuously variable transmission,

• the belt-type continuously variable transmission comprising:
• a primary pulley to which a primary pressure is supplied;
• a secondary pulley to which a secondary pressure is supplied;
• and
• a belt wound around the primary pulley and the secondary pulley, wherein a pulley pressing force is determined by the primary pressure and the secondary pressure;
• the method comprising:
• performing a process by a transmission shift controller, when performing a low speed position return shift to shift a transmission ratio of the belt-type continuously variable transmission toward a lowermost speed position while a vehicle is decelerating, wherein the process includes:
• calculating a primary pressure actual lower limit, at which the belt actually starts to slip, based on the transmission ratio and a deceleration of the vehicle;
• setting a lower limit of a setpoint of the primary pressure to the primary pressure actual lower limit;
• setting the primary pressure actual lower limit higher with a locking tendency of a vehicle wheel detected than that without the locking tendency detected;
• and
• setting the primary pressure actual lower limit with the locking tendency detected to increase as the transmission ratio varies toward the lowermost speed position.