Abstract: A vehicle power unit is provided in which a transmission including a gear transmission mechanism and a gear selector mechanism is housed in a transmission case, the gear transmission mechanism having gear trains with a plurality of gear positions that can be established alternatively, the gear selector mechanism being capable of operating s as to alternatively establish the gear trains with the plurality of gear positions, and a plurality of rotational speed sensors individually detecting the rotational speed of a plurality of rotating members forming part of the transmission are mounted on the transmission case, wherein the plurality of rotational speed sensors are disposed in a distributed manner so as to sandwich the plurality of shaft members of the gear selector mechanism in a projection on a plane orthogonal to a central axis of a crankshaft.

Abstract: A power unit having a crankcase and peripheral devices wherein a driving source for a gear shifting device is disposed so as to be displaced below the crankcase. An engine includes a gear speed change mechanism having a plurality of gear pairs for changing the speed of a rotational force of a crankshaft. A gear shifting device includes at least a plate-shaped shift arm rocking about a shift spindle to perform a gear pair changing operation on the gear speed change mechanism. A crankcase houses the gear speed change mechanism and the gear shifting device with an oil pan attached to a lower portion of the crankcase. A communicating hole communicating with the oil pan is formed in a bottom portion of the crankcase with the bottom portion being located below the shift arm, and a rocking range of the shift arm partly overlaps the communicating hole.

Abstract: A vehicle power unit is provided in which a transmission including a gear transmission mechanism and a gear selector mechanism is housed in a transmission case, the gear transmission mechanism having gear trains with a plurality of gear positions that can be established alternatively, the gear selector mechanism being capable of operating s as to alternatively establish the gear trains with the plurality of gear positions, and a plurality of rotational speed sensors individually detecting the rotational speed of a plurality of rotating members forming part of the transmission are mounted on the transmission case, wherein the plurality of rotational speed sensors are disposed in a distributed manner so as to sandwich the plurality of shaft members of the gear selector mechanism in a projection on a plane orthogonal to a central axis of a crankshaft.

Abstract: A power unit having a crankcase and peripheral devices wherein a driving source for a gear shifting device is disposed so as to be displaced below the crankcase. An engine includes a gear speed change mechanism having a plurality of gear pairs for changing the speed of a rotational force of a crankshaft. A gear shifting device includes at least a plate-shaped shift arm rocking about a shift spindle to perform a gear pair changing operation on the gear speed change mechanism. A crankcase houses the gear speed change mechanism and the gear shifting device with an oil pan attached to a lower portion of the crankcase. A communicating hole communicating with the oil pan is formed in a bottom portion of the crankcase with the bottom portion being located below the shift arm, and a rocking range of the shift arm partly overlaps the communicating hole.

Abstract: A power unit case for a power unit, including an internal combustion engine and a transmission, makes it possible to enhance the lubrication of a desired meshing portion of a group of transmission gears, while reducing the size of the engine. In the power unit case, a main shaft is arranged above a space between a crankshaft and a counter shaft arranged at a position substantially horizontally behind the crankshaft. A gear-ratio selecting member is arranged above a group of transmission gears on the counter shaft whose upper portion rotates toward a meshing portion between groups of transmission gears, and a lubricating projection that projects downwardly is formed in the transmission case above each of the transmission gears on the counter shaft and at a location on a ceiling surface of the transmission case where the gear-ratio selecting member is supported.

Abstract: A power unit case for a power unit, including an internal combustion engine and a transmission, makes it possible to enhance the lubrication of a desired meshing portion of a group of transmission gears, while reducing the size of the engine. In the power unit case, a main shaft is arranged above a space between a crankshaft and a counter shaft arranged at a position substantially horizontally behind the crankshaft. A gear-ratio selecting member is arranged above a group of transmission gears on the counter shaft whose upper portion rotates toward a meshing portion between groups of transmission gears, and a lubricating projection that projects downwardly is formed in the transmission case above each of the transmission gears on the counter shaft and at a location on a ceiling surface of the transmission case where the gear-ratio selecting member is supported.