Abstract: A power train component such as a gearbox includes driving and driven, coaxially arranged cooperating gears which engage each other via teeth. The engaging end surfaces of the teeth are provided with a first chamfer and a second chamfer, in which the chamfer edge is offset from bisecting the tooth. Preferably the offset chamfer edges are provided on both a driving gear (shifter), axially positionable using a shifting fork on a shift drum, and a driven low gear. In one preferred driving gear (shifter) design, the offset chamfer edges are only provided for the side engaged when the shifting fork moves against a spring force. The invention facilitates smoother and less binding movement between the non-engaged and the engaged axial positions, such that the gear can be more easily shifted by the shifting fork in at least one direction.

Abstract: A shift drum has a recess which controls a fork to move one of two cooperating coaxially arranged gears for transmitting torque in a power train of a vehicle. The recess includes a straight section, which upon rotation of the shift drum does not move the fork either to the left or the right, and at least one ramp which does move the fork in one direction (i.e., to the left or the right). The ramp is more complex than a single line, such as having a first portion at a first right-shift portion ramp angle ? and a second portion at a second right-shift portion ramp angle ?, perhaps with the intersection between the first right-shift portion ramp angle ? and the second right-shift portion ramp angle ? being at the mid-line defined by the straight section of the recess.

Abstract: A power train component such as a gearbox includes driving and driven, coaxially arranged cooperating gears which engage each other via teeth. The engaging end surfaces of the teeth are provided with a first chamfer and a second chamfer, in which the chamfer edge is offset from bisecting the tooth. Preferably the offset chamfer edges are provided on both a driving gear (shifter), axially positionable using a shifting fork on a shift drum, and a driven low gear. In one preferred driving gear (shifter) design, the offset chamfer edges are only provided for the side engaged when the shifting fork moves against a spring force. The invention facilitates smoother and less binding movement between the non-engaged and the engaged axial positions, such that the gear can be more easily shifted by the shifting fork in at least one direction.

Abstract: A shift drum has a recess which controls a fork to move one of two cooperating coaxially arranged gears for transmitting torque in a power train of a vehicle. The recess includes a straight section, which upon rotation of the shift drum does not move the fork either to the left or the right, and at least one ramp which does move the fork in one direction (i.e., to the left or the right). The ramp is more complex than a single line, such as having a first portion at a first right-shift portion ramp angle ? and a second portion at a second right-shift portion ramp angle ?, perhaps with the intersection between the first right-shift portion ramp angle ? and the second right-shift portion ramp angle ? being at the mid-line defined by the straight section of the recess.