Balancer system for internal combustion engine

A balancer system in an internal combustion engine which comprises a crankcase, a crankshaft rotatably supported in said crankcase, a clutch, and a transmission including a main shaft extending parallel to the crankshaft and operatively coupled to said crankshaft through said clutch, a transmission gear train, and a countershaft operatively coupled to said main shaft through said transmission gear train, said balancer system comprising:

• a pair of balancer shafts;
• and
• a pair of first and second primary counterbalances supported on said balancer shafts, respectively, for rotation about axes parallel to said crankshaft in ganged relation to said crankshaft at the same speed as and in the opposite direction to said crankshaft;
• one of said balancer shafts comprising said main shaft of the transmission, said first primary counterbalance being rotatably supported on one end of said main shaft.

A balancer system in an internal combustion engine which comprises a crankcase, a crankshaft rotatably supported in said crankcase, a clutch, and a transmission including a main shaft extending parallel to the crankshaft and operatively coupled to said crankshaft through said clutch, a transmission gear train, and a countershaft operatively coupled to said main shaft through said transmission gear train, said balancer system comprising:

• a pair of balancer shafts;
• and
• a pair of first and second counterbalances supported on said balancer shafts, respectively, for rotation about axes parallel to said crankshaft in ganged relation to said crankshaft at a speed twice the speed of the crankshaft and in mutually opposite directions;
• said counterbalances being disposed closely to a plane which passes near a substantially central portion of the crankshaft in the crankcase and extends perpendicularly to said crankshaft.

A balancer system in an internal combustion engine which comprises a crankcase, a crankshaft rotatably supported in said crankcase, a clutch, and a transmission including a main shaft extending parallel to the crankshaft and operatively coupled to said crankshaft through said clutch, a transmission gear train, and a countershaft operatively coupled to said main shaft through said transmission gear train, said balancer system comprising:

• a pair of balancer shafts;
• and
• a pair of first and second counterbalances supported on said balancer shafts, respectively, for rotation about axes parallel to said crankshaft in ganged relation to said crankshaft at a speed twice the speed of the crankshaft and in mutually opposite directions;
• one of said balancer shafts comprising said countershaft of the transmission, said first counterbalance being rotatably supported on said countershaft..

A balancer system in an internal combustion engine which comprises a crankcase, a crankshaft rotatably supported in said crankcase, a clutch, and a transmission including a main shaft extending parallel to the crankshaft and operatively coupled to said crankshaft through said clutch, a transmission gear train, and a countershaft operatively coupled to said main shaft through said transmission gear train, said balancer system comprising:

• a plurality of balancer shafts;
• a pair of first and second primary counterbalances supported on two of said balancer shafts, respectively, for rotation about axes parallel to said crankshaft in ganged relation to said crankshaft at the same speed as and in the opposite direction to said crankshaft;
• and
• a pair of first and second secondary counterbalances supported on two of said balancer shafts, respectively, for rotation about axes parallel to said crankshaft in ganged relation to said crankshaft at a speed twice the speed of the crankshaft and in mutually opposite directions;
• the balancer shafts which support said first primary counterbalance and said first secondary counterbalance comprising said main shaft and said countershaft of the transmission, said first primary counterbalance being rotatably supported on said main shaft, and said first secondary counterbalance being rotatably supported on said countershaft.