good. this helps me locate where to start at least:)
I even didn't try to understand it yet yesterday.
Now, I get the NORTH:)
This is another understanding of mine yesterday.
The release bearing is on the main shaft (?).
它外径是普通圆，尺寸应该比pressure plate的finger内径大，
踩离合后压紧diaphragm springer finger，松开pressure plate；
它内径是个斜向齿轮，松开离合的时候与main shaft的外斜向齿轮耦合。
bearing的后面外径被release fork卡紧不能转动，这样，
double clutch的话，main shaft一定会被转过一定角
