Dog-clutch transmission system

A dog-clutch transmission system comprising:

• a main shaft;
• a counter shaft;
• a plurality of first gears installed on the main shaft and the counter shaft, respectively, said plurality of first gears not being rotatable relatively to the main shaft and counter shaft and being axially slidable;
• and
• a plurality of second gears installed so on the main shaft and counter shaft, respectively, said plurality of second gears being rotatable relatively to the main shaft and counter shaft and not being axially slidable,
• wherein each of the plurality of first gears has dog-teeth projecting in an axial direction and each of the plurality of second gears has dog-holes recessed in the axial direction,
• wherein speed-stages are switchable by bringing the dog-teeth and the dog-holes into engagement and disengagement,
• wherein a speed-change ratio proportion of a change-speed ratio at an arbitrary n-speed speed-stage to a speed-change ratio at a (n+1)-speed speed-stage is set at 0.725 or more, and
• wherein a dog engagement difference rotational energy of the dog-teeth and the dog-holes is smaller than 30 joules.