Offset chamfered teeth for coaxial cooperating gears in vehicle power trains

A power train component for a vehicle comprising:

• a shift drum having a shift recess on its outer periphery;
• a fork movable based on the shape of the shift recess;
• a rotatable shaft carrying power train torque;
• a first gear transferring power train torque to or from the shaft, the first gear having a first gear engagement face, with at least ten first gear teeth accessible on the first gear engagement face;
• and
• a second gear rotationally mountable on the shaft so as to be rotatable relative to the shaft, the second gear having a second gear engagement face, with at least ten second gear teeth accessible on the second gear engagement face;
• wherein at least one of the first gear and the second gear are axially moveable on the shaft by the fork based upon rotational movement of the shift drum, such that when the first gear and the second gear are arranged on the shaft with the first gear engagement face facing the second gear engagement face, the gears can be axially moved by the fork between a non-engaged position where the first gear teeth and the second gear teeth are not interlocked with each other and an engaged position where the first gear teeth and the second gear teeth are interlocked with each other;
• and
• wherein either the first gear teeth or the second gear teeth or both the first gear teeth and the second gear teeth, on their engagement face, have a leading chamfer and a trailing chamfer intersecting at a chamfer edge, wherein each chamfer edge is offset from a center symmetry line of the gear tooth.

A vehicle comprising:

• a seat for an operator;
• a one or two cylinder internal combustion engine for propelling the vehicle;
• and
• a power train delivering torque from the engine to propel the vehicle, the power train including at least one power train component comprising:
• a shift drum having a shift recess on its outer periphery;
• a fork movable based on the shape of the shift recess;
• a rotatable shaft carrying power train torque;
• a first gear transferring power train torque to or from the shaft, the first gear having a first gear engagement face, with at least ten first gear teeth accessible on the first gear engagement face;
• and
• a second gear rotationally mountable on the shaft so as to be rotatable relative to the shaft, the second gear having a second gear engagement face, with at least ten second gear teeth accessible on the second gear engagement face;
• wherein at least one of the first gear and the second gear are axially moveable on the shaft by the fork based upon rotational movement of the shift drum, such that when the first gear and the second gear are arranged on the shaft with the first gear engagement face facing the second gear engagement face, the gears can be axially moved by the fork between a non-engaged position where the first gear teeth and the second gear teeth are not interlocked with each other and an engaged position where the first gear teeth and the second gear teeth are interlocked with each other;
• and
• wherein either the first gear teeth or the second gear teeth or both the first gear teeth and the second gear teeth, on their engagement face, have a leading chamfer and a trailing chamfer intersecting at a chamfer edge, wherein each chamfer edge is offset from a center symmetry line of the gear tooth.

A power train component for a vehicle comprising:

• a shift drum having a shift recess on its outer periphery;
• a fork movable based on the shape of the shift recess;
• a rotatable shaft carrying power train torque;
• a first gear transferring power train torque to or from the shaft, the first gear having a first gear engagement face, with at least ten first gear teeth accessible on the first gear engagement face;
• and
• a second gear rotationally mountable on the shaft so as to be rotatable relative to the shaft, the second gear having a second gear engagement face, with at least ten second gear teeth accessible on the second gear engagement face;
• wherein at least one of the first gear and the second gear are axially moveable on the shaft by the fork based upon rotational movement of the shift drum, such that when the first gear and the second gear are arranged on the shaft with the first gear engagement face facing the second gear engagement face, the gears can be axially moved by the fork between a non-engaged position where the first gear teeth and the second gear teeth are not interlocked with each other and an engaged position where the first gear teeth and the second gear teeth are interlocked with each other;
• and
• wherein either the first gear teeth or the second gear teeth or both the first gear teeth and the second gear teeth, on their engagement face, have a leading chamfer and a trailing chamfer intersecting at a chamfer edge;
• further comprising a spring providing a spring force which biases the first gear away from the second gear, wherein the shift recess comprises a ramp which, upon movement of the shift drum, can provide a force overcoming the spring force to move the first gear to the engaged position.