A gear device includes a first gear, a second gear, and a third gear. The second gear is offset eccentrically when the first gear is rotated. The third gear is rotated at a speed slower than a rotation speed of the first gear when the second gear is offset eccentrically. The stopper plate is engaged with the second gear through a fitting structure thereby restricting rotational movement of the second gear while permitting linear movement of the second gear. One of the second gear and the stopper plate includes an engagement claw. The other one of the second gear and the stopper plate includes a recess engaged with the engagement claw. The engagement claw includes a grease sump that holds grease applied between the recess and the engagement claw.

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 β and a second portion at a second right-shift portion ramp angle γ, perhaps with the intersection between the first right-shift portion ramp angle β and the second right-shift portion ramp angle γ being at the mid-line defined by the straight section of the recess.

A transmission includes a rotating shaft, a sleeve configured to rotate around an axial center of the rotating shaft, a fork engaged with an external circumference of the sleeve, and a shift shaft disposed parallel to the rotating shaft and supporting the fork. The fork includes a support part supported by the shift shaft, a first arm part extending from the support part in a circumferential direction of the rotating shaft and disposed above the sleeve, and an oil receiving part disposed on the first arm part. The oil receiving part has an elongated hole that extends in a direction perpendicular to an axial direction of the rotating shaft as seen in a top view.

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.

A gear device includes a first gear, a second gear, and a third gear. The second gear is offset eccentrically when the first gear is rotated. The third gear is rotated at a speed slower than a rotation speed of the first gear when the second gear is offset eccentrically. The stopper plate is engaged with the second gear through a fitting structure thereby restricting rotational movement of the second gear while permitting linear movement of the second gear. One of the second gear and the stopper plate includes an engagement claw. The other one of the second gear and the stopper plate includes a recess engaged with the engagement claw. The engagement claw includes a grease sump that holds grease applied between the recess and the engagement claw.

A transmission shift fork comprising: an arch-shaped portion, where a pair of lobes are radially and inwardly projecting from an inner surface of the arch-shaped portion directing oil to a sleeve engagement region of a clutch.

A lubrication system for a clutch. Where the system comprises: a pump; one or more conduits connected to the pump; and at least one body coupled to a shift arm for engaging a sleeve, where the at least one body comprises an inlet connected to a conduit from the one or more conduits, at least one outlet, and an internal passage being in fluid communication between the inlet and the at least one outlet, where lubricant passing through the conduit exits at the at least one outlet to lubricate the body and the sleeve.

A lubrication system for a transmission, comprising: a shaft of the transmission having a fluid passage, where the fluid passage is centered on an axis that is parallel and non-coaxial to a rotational axis of the shaft, where the shaft is centered on the rotational axis; and at least two axially spaced apart radial channels, where the two axially spaced apart radial channels are fluidly communicating with the fluid passage and inclined at different angles with respect to a plane that cross-sections the shaft in a longitudinal direction with respect to the rotational axis, where the plane includes the rotational axis and the axis of the fluid passage, where the different angles decrease in size for each axially spaced apart radial channel that is further from an inlet relative to a previous spaced apart radial channel.