Lubricating system for toroidal continuously variable transmission

A lubricating system for a toroidal continuously variable transmission equipped with a trunnion rotatably supporting a power roller gripped between input and output disks so that a gyration angle of the power roller is variable, comprising:

• a rolling contact surface lubrication circuit provided for lubrication of a rolling contact surface on which the input and output disks are in friction-contact with the power roller via traction oil;
• a trunnion lubrication circuit provided for lubrication and cooling of the trunnion and the power roller;
• and
• an oil-temperature control means provided in the rolling contact surface lubrication circuit for temperature-controlling the traction oil, so that the traction oil temperature-controlled by the oil-temperature control means is supplied through the rolling contact surface lubrication circuit into the rolling contact surface.

A method for independently temperature-controlling traction oil in a dual circuit lubricating system for a toroidal continuously variable transmission equipped with a trunnion rotatably supporting a power roller gripped between input and output disks so that a gyration angle of the power roller is variable, the dual circuit lubricating system having a first lubricating circuit for lubrication of a rolling contact surface on which the input and output disks are in friction-contact with the power roller via the traction oil, a second lubricating circuit for lubrication and cooling of the trunnion and the power roller, an oil heater heating the traction oil and an oil cooler cooling the traction oil, the method comprising:

• detecting a condition of an operating temperature of the toroidal continuously variable transmission;
• determining, responsively to the condition of the operating temperature detected, as to whether the toroidal continuously variable transmission is in a cold-transmission state or in a hot-transmission state;
• supplying the traction oil cooled by the cooler via the second lubricating circuit for lubrication and cooling of the trunnion and the power roller;
• supplying the traction oil temperature-risen by the heater via the first lubricating circuit for lubrication of the rolling contact surface when the toroidal continuously variable transmission is in the cold-transmission state;
• and
• supplying the traction oil temperature-fallen by the cooler via the first lubricating circuit for lubrication of the rolling contact surface when the toroidal continuously variable transmission is in the hot-transmission state.