Control device for transmission and braking torque generating determination method for transmission

A control device for a transmission including m (m≧3) solenoid valves, each of the m solenoid valves comprising a solenoid, and configured to establish a plurality of shift speeds by engaging n1 (2≦n1<m) engagement elements using hydraulic pressures of n1 solenoid valves among the m solenoid valves, the control device comprising:

• a threshold setting unit that sets respective adjustable condition values for n2 (n1<n2≦m) solenoid valves corresponding to n2 engagement elements at the time when braking torque acts on an output shaft of the transmission with the n2 engagement elements engaged as condition threshold values;
• a determination unit that determines whether or not braking torque is generated on the output shaft of the transmission by comparing respective condition values for the n2 solenoid valves and the set condition threshold values corresponding to the n2 solenoid valves;
• and
• a determination element setting unit that sets n2 engagement elements among the m engagement elements as n2 determination elements, wherein
• the threshold setting unit sets an adjustable condition value for each of n2 determination valves which are n2 solenoid valves corresponding to the set n2 determination elements, for when braking torque acts on the output shaft of the transmission with the set n2 determination elements engaged, as the condition threshold value on the basis of a combination of the set n2 determination elements,
• the n2 is a value that is larger than the n2 by a value of 1, and
• the threshold setting unit performs the condition threshold setting process by setting predetermined-time assumed drag torque, which serves as drag torque assumed to be generated by engagement of the subject element when the n2 determination elements are engaged, on the basis of a first speed change ratio, a second speed change ratio, and torque input to an input shaft of the transmission, the first speed change ratio being a ratio in rotational speed between the input shaft and the output shaft of the transmission at the time when n1 non-subject elements, which are n1 of the n2 determination elements excluding the subject element, are engaged, and the second speed change ratio being a ratio between a subject element rotational speed difference, which is a difference in rotational speed between an input side and an output side of the subject element, and a rotational speed of the output shaft of the transmission at the time when the n1 non-subject elements are engaged, and setting a condition for the subject valve corresponding to the set predetermined-time assumed drag torque as the condition threshold value.