RECIPROCATING INTERNAL COMBUSTION ENGINE, CRANKSHAFT, VEHICLE AND MOTORCYCLE

摘要

PROBLEM TO BE SOLVED: To provide an engine enabling efficient generation of an unbalanced moment and suppression of the overall weight.SOLUTION: A crankshaft 60 includes a plurality of crank pins 641-644 disposed therein and has rotating couple. A crank case 810 rotatably supports a plurality of journals 621-625 of the crankshaft 60. The crank case 810 includes a thrust receiving portion 680 for restricting movement in the thrust direction of the crankshaft 60. On an outer periphery of a counter weight 637 disposed at one end of the crankshaft 60 out of a plurality of counter weights 631-638 that are disposed in the crankshaft 60 to axially separate from each other, a gear 639 for outputting rotating power of the engine is formed. The thrust receiving portion 680 is installed on a side face of a journal receiving inner wall 812 disposed on the other end side of the crankshaft 60.