Control unit for synchronous engaging device

A control unit for synchronous engaging device, comprising:

• an input shaft of a transmission;
• one or more input gears on the input shaft to transmit rotation of the input shaft;
• an output shaft in parallel with the input shaft;
• one or more output gears on the output shaft to engage with each of the one or more input gears;
• a synchronous engaging device having a sleeve movable between an engaging position and a release position where said engaging position is released, said engaging position engaging by:
• synchronizing rotation of one of the input gears with rotation of the input shaft, or
• synchronizing rotation of one of the output gears with the output shaft;
• an actuator driving the sleeve;
• a controller that controls operation of the synchronous engaging device;
• a rotation detection sensor that detects an input rotation on the input shaft and an output rotation on the output shaft;
• a position information acquisition sensor for acquiring information related to a position of the sleeve;
• and
• a memory which stores a damage determination index for determining degree of damage of the synchronous engaging device;
• wherein, when the sleeve is moved from the release position to the engaging position in response to a shift request, the controller calculates a differential rotation speed between the input rotation and the output rotation after a synchronization completion position is reached,
• wherein the synchronization completion position is a position where either
• synchronization of rotation of the one of the input gears with rotation of the input shaft is complete, or
• synchronization of rotation of the one of the output gears with the output shaft is complete, and
• wherein, when the differential rotation speed is equal to or more than a first predetermined threshold value, the controller calculates the damage determination index based on the differential rotation speed and then accumulates the damage determination index for each gear position before determining whether or not a cumulative value of the damage determination indices calculated for each gear position is equal to or more than a second predetermined threshold value.