Transmission control device and transmission control method

A transmission control method for controlling a transmission, the transmission having:

• a variator having a primary pulley whose groove width is changed by controlling a primary pressure serving as control pressure of the primary pulley, a secondary pulley whose groove width is changed by controlling a secondary pressure serving as control pressure of the secondary pulley, and a belt looped over the primary pulley and the secondary pulley;
• a hydraulic line-pressure actuator configured to control actual pressure of a line pressure serving as a source pressure of the primary pressure and the secondary pressure;
• a hydraulic primary-pressure actuator configured to control actual pressure of the primary pressure;
• and
• a hydraulic secondary-pressure actuator configured to control actual pressure of the secondary pressure, the control method for performing control of the transmission, the control method comprising:
• determining failure of the hydraulic secondary-pressure actuator;
• variably controlling a line command pressure serving as command pressure to the hydraulic line-pressure actuator, and in a case where the failure is determined, fixing the line command pressure to a line pressure set value which is a first predetermined value or more;
• variably controlling a primary command pressure serving as command pressure to the hydraulic primary-pressure actuator, and in a case where the failure is determined, continuously changing a speed ratio of the variator by variably controlling the primary command pressure;
• and
• variably controlling a secondary command pressure serving as command pressure to the hydraulic secondary-pressure actuator, and in a case where the failure is determined, fixing the secondary command pressure to a secondary pressure set value which is a second predetermined value or more.

A transmission control device for controlling a transmission, the transmission having:

• a variator having a primary pulley whose groove width is changed by controlling a primary pressure serving as control pressure of the primary pulley, a secondary pulley whose groove width is changed by controlling a secondary pressure serving as control pressure of the secondary pulley, and a belt looped over the primary pulley and the secondary pulley;
• a hydraulic line-pressure actuator configured to control actual pressure of a line pressure serving as a source pressure of the primary pressure and the secondary pressure;
• a hydraulic primary-pressure actuator configured to control actual pressure of the primary pressure;
• and
• a hydraulic secondary-pressure actuator configured to control actual pressure of the secondary pressure,
• the transmission control device comprising:
• failure determination means for determining failure of the hydraulic secondary-pressure actuator;
• line command pressure control means for variably controlling a line command pressure serving as command pressure to the hydraulic line-pressure actuator, and in a case where the failure is determined, to fix the line command pressure to a line pressure set value which is a first predetermined value or more;
• primary command pressure control means for variably controlling a primary command pressure serving as command pressure to the hydraulic primary-pressure actuator, and in a case where the failure is determined, to continuously change a speed ratio of the variator by variably controlling the primary command pressure;
• and
• secondary command pressure control means for variably controlling a secondary command pressure serving as command pressure to the hydraulic secondary-pressure actuator, and in a case where the failure is determined, to fix the secondary command pressure to a secondary pressure set value which is a second predetermined value or more.