Abstract: A breather chamber structure for an internal combustion engine wherein the breather chamber can be disposed compactly and the degree of freedom in the layout of the parts of the internal combustion engine can be raised. The breather chamber structure includes a crankcase, a cylinder body provided upwardly on the crankcase, and a breather chamber configured to separate oil from oil mist in the crankcase. The breather chamber includes a crankcase side breather chamber provided in the crankcase and open to a joining plane between the crankcase and the cylinder body, and a cylinder side breather chamber provided in the cylinder body and open to the joining plane.

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 breather chamber structure for an internal combustion engine wherein the breather chamber can be disposed compactly and the degree of freedom in the layout of the parts of the internal combustion engine can be raised. The breather chamber structure includes a crankcase, a cylinder body provided upwardly on the crankcase, and a breather chamber configured to separate oil from oil mist in the crankcase. The breather chamber includes a crankcase side breather chamber provided in the crankcase and open to a joining plane between the crankcase and the cylinder body, and a cylinder side breather chamber provided in the cylinder body and open to the joining plane.

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 water-cooled engine includes first connection paths continuous with a cylinder-head-side water jacket and a second connection path continuous with a cylinder-body-side water jacket. The paths are disposed in a sidewall of a cylinder body. A thermostat valve is attached to the sidewall. An oil cooler having a cooling water lead-in pipe and a cooling water lead-out pipe is attached to one sidewall of an engine main body to face the same direction as that of the thermostat valve. The cooling water lead-in pipe and the cooling water lead-out pipe are connected to the thermostat valve.

Abstract: In a vehicle having a generator cover mounted on one side of a crankcase so as to cover an end portion of a crankshaft projecting from the crankcase and a shift spindle located on the rear side of the generator cover as an input member of a shifting mechanism, a shift actuator is located below the longitudinal range of the generator cover in parallel to the crankshaft and on the front side of the axis of the shift spindle.

Abstract: An internal combustion engine is provided with a plurality of hydraulic clutches, a plurality of hydraulic controlling valves for individually controlling the oil pressure for the hydraulic clutches, and a plurality of clutch oil pressure sensors for individually detecting the controlling oil pressure of controlling oil supplying paths interconnecting the hydraulic controlling valves and the hydraulic clutches. The oil pressure sensors individually correspond to the hydraulic clutches compactly, thereby to preventing an increase in size. The clutch oil pressure sensors are provided on an engine main body so as to be disposed in the proximity of and in parallel to each other while axial directions thereof are directed in a forward and backward direction of a saddle type vehicle in a state in which the engine main body is mounted on the saddle type vehicle.

Abstract: A hydraulic clutch control device of a vehicle power unit in which the oil pressure control valve is prevented from being exposed above the oil level even when a vehicle body inclines frontward or rearward. A housing chamber housing an actuator is formed in a housing chamber forming body attached to an engine main body and an oil pressure control valve partially facing the housing chamber is supported by the housing chamber forming body. An oil return hole used to return excess hydraulic oil from the housing chamber into the engine main body is provided in the housing chamber forming body to communicate with an upper portion of the housing chamber at an end portion of the housing chamber on a side close to the oil pressure control valve.

Abstract: A water-cooled engine includes first connection paths continuous with a cylinder-head-side water jacket and a second connection path continuous with a cylinder-body-side water jacket. The paths are disposed in a sidewall of a cylinder body. A thermostat valve is attached to the sidewall. An oil cooler having a cooling water lead-in pipe and a cooling water lead-out pipe is attached to one sidewall of an engine main body to face the same direction as that of the thermostat valve. The cooling water lead-in pipe and the cooling water lead-out pipe are connected to the thermostat valve.

Abstract: A scroll compressor including a stationary scroll formed with a scroll wrap, an orbiting scroll formed with a scroll wrap, a rotating shaft for putting the orbiting scroll into an orbiting motion, a rotating bearing for rotatably supporting the rotating shaft on the stationary scroll, an orbiting scroll bearing provided at an eccentric shaft portion of the rotating shaft and operative to orbitably support a central portion of the orbiting scroll. A coupling transmits a torque of a driving shaft to the rotating shaft. The scroll compressor is compact based on the layout of a balancer. The orbiting scroll bearing is disposed at a central portion of the rotating shaft, and the coupling is provided with the balancer. The stationary scroll may be provided with ribs being formed therein with an oil passage for connection between a central oil passage formed in the rotating shaft and the exterior.

Abstract: A hydraulic clutch control device of a vehicle power unit in which the oil pressure control valve is prevented from being exposed above the oil level even when a vehicle body inclines frontward or rearward. A housing chamber housing an actuator is formed in a housing chamber forming body attached to an engine main body and an oil pressure control valve partially facing the housing chamber is supported by the housing chamber forming body. An oil return hole used to return excess hydraulic oil from the housing chamber into the engine main body is provided in the housing chamber forming body to communicate with an upper portion of the housing chamber at an end portion of the housing chamber on a side close to the oil pressure control valve.

Abstract: An internal combustion engine is provided with a plurality of hydraulic clutches, a plurality of hydraulic controlling valves for individually controlling the oil pressure for the hydraulic clutches, and a plurality of clutch oil pressure sensors for individually detecting the controlling oil pressure of controlling oil supplying paths interconnecting the hydraulic controlling valves and the hydraulic clutches. The oil pressure sensors individually correspond to the hydraulic clutches compactly, thereby to preventing an increase in size. The clutch oil pressure sensors are provided on an engine main body so as to be disposed in the proximity of and in parallel to each other while axial directions thereof are directed in a forward and backward direction of a saddle type vehicle in a state in which the engine main body is mounted on the saddle type vehicle.

Abstract: In a vehicle having a generator cover mounted on one side of a crankcase so as to cover an end portion of a crankshaft projecting from the crankcase and a shift spindle located on the rear side of the generator cover as an input member of a shifting mechanism, a shift actuator is located below the longitudinal range of the generator cover in parallel to the crankshaft and on the front side of the axis of the shift spindle.

Abstract: A scroll compressor including a stationary scroll formed with a scroll wrap, an orbiting scroll formed with a scroll wrap, a rotating shaft for putting the orbiting scroll into an orbiting motion, a rotating bearing for rotatably supporting the rotating shaft on the stationary scroll, an orbiting scroll bearing provided at an eccentric shaft portion of the rotating shaft and operative to orbitably support a central portion of the orbiting scroll. A coupling transmits a torque of a driving shaft to the rotating shaft. The scroll compressor is compact based on the layout of a balancer. The orbiting scroll bearing is disposed at a central portion of the rotating shaft, and the coupling is provided with the balancer. The stationary scroll may be provided with ribs being formed therein with an oil passage for connection between a central oil passage formed in the rotating shaft and the exterior.

Abstract: To provide a layout structure of a clutch lever shaft capable of realizing compact layouts of a whole power unit in which a starter centrifugal clutch and a transmission manual multi-plate clutch are provided, and of a whole vehicle on which the power unit is mounted. A centrifugal clutch shaft and a manual multi-plate clutch shaft are disposed in parallel. The clutch lever shaft of the manual multi-plate clutch is disposed orthogonally and substantially vertically upward in relation to a pressing direction of a friction plate in a vicinity of an end portion of a lifter pin. The clutch lever shaft is disposed between the centrifugal clutch and the manual multi-plate clutch when viewed from a top of the power unit.

Abstract: An air-cooled internal combustion engine includes a cylinder block having a plurality of cylinder bores disposed in parallel to each other, a cylinder head secured to an upper portion of the cylinder block, a crankshaft, two camshafts disposed in a parallel, juxtaposed relationship to each other so as to extend perpendicularly to a forward and backward direction of a vehicle on which the engine is mounted at an upper portion of said cylinder head and positioned on front and rear sides of the engine relative to each other, and a camshaft driving mechanism for transmitting rotational driving force of the crankshaft to the camshafts. A cooling space into which wind can be introduced is formed below that one of the camshafts which is positioned on the front side of the engine. The entire cylinder head is thus cooled efficiently, including portions corresponding to the cylinders disposed at intermediate positions of the engine.

Abstract: To provide a layout structure of a clutch lever shaft capable of realizing compact layouts of a whole power unit in which a starter centrifugal clutch and a transmission manual multi-plate clutch are provided, and of a whole vehicle on which the power unit is mounted. A centrifugal clutch shaft and a manual multi-plate clutch shaft are disposed in parallel. The clutch lever shaft of the manual multi-plate clutch is disposed orthogonally and substantially vertically upward in relation to a pressing direction of a friction plate in a vicinity of an end portion of a lifter pin. The clutch lever shaft is disposed between the centrifugal clutch and the manual multi-plate clutch when viewed from a top of the power unit.

Abstract: An air-cooled internal combustion engine includes a cylinder block having a plurality of cylinder bores disposed in parallel to each other, a cylinder head secured to an upper portion of the cylinder block, a crankshaft, two camshafts disposed in a parallel, juxtaposed relationship to each other so as to extend perpendicularly to a forward and backward direction of a vehicle on which the engine is mounted at an upper portion of said cylinder head and positioned on front and rear sides of the engine relative to each other, and a camshaft driving mechanism for transmitting rotational driving force of the crankshaft to the camshafts. A cooling space into which wind can be introduced is formed below that one of the camshafts which is positioned on the front side of the engine. The entire cylinder head is thus cooled efficiently, including portions corresponding to the cylinders disposed at intermediate positions of the engine.