Abstract: A vehicle transmission includes a crankshaft extending through a seal cover and into an oil-storing end portion of a driven shaft. The oil-storing end portion of the driven shaft defines a lubricating space filled with lubricating oil, and extends into the seal cover. A unidirectional clutch is disposed in the lubricating space and outwardly of the seal cover.

Abstract: A gear-shifting structure is provided for a vehicle. The vehicle includes a transmission box that contains therein a gear train, a clutch, a switching fork, a gear-shifting hub, and a motor. The motor cooperates with a worm shaft to actuate the clutching operation of the clutch and to cause movement of the gear-shifting hub in order to carry out the gear shifting operation. The motor has a rotary member that drives the worm shaft on which a worm and a cam are mounted. To effect gear shifting, the motor drives the worm shaft to have the cam abut and displace the clutch and at the same time, the worm drives the gear-shifting hub to thus realize the operation of gear shifting.

Abstract: A vehicle transmission includes a crankshaft box unit, a clutch unit, and a transmission box unit. The crankshaft box unit includes a crankshaft box, a crankshaft extending through the clutch unit and into the transmission box unit, a driven shaft disposed in the transmission box unit and having an end sleeved on a connecting end of the crankshaft, and a bearing disposed between the crankshaft and the driven shaft. The clutch unit includes a seal cover disposed in proximity to the crankshaft box, and a wet clutch disposed between the seal cover and the crankshaft box. The crankshaft extends through the seal cover. The connecting end of the crankshaft is disposed in a transmission box of the transmission box unit.

Abstract: A cooling structure for a continuous variation transmission system of an all-terrain vehicle which includes a radiator mounted at a front end of the vehicle and under a front body cover, a hood enclosing the radiator, a gearbox having an inlet and an outlet, the inlet being connected with an inlet conduit for drawing outside cool air into the gearbox, the outlet being connected with an exhaust conduit for discharging hot air from the gearbox, wherein the inlet conduit has an inlet end mounted between the hood and the front body cover and shielded by the hood and the front body cover, whereby the cooling structure can effectively prevent water, dirt and dust from entering the gearbox and are simple in construction and easy to assemble and maintain.

Abstract: This invention is to provide a tappet clearance adjusting cover coupled with a secondary air valve. The tappet clearance adjusting cover is disposed on a cylinder head of an engine. The secondary air valve includes a recessed element and a cap which jointly form a receiving space receiving therein a one-way valve. The recessed element is provided with an inlet pipe interposed between the cap and the tappet clearance adjusting cover. By disposing the secondary air valve on the tappet clearance adjusting cover and arranging the inlet pipe between the cap and the tappet clearance adjusting cover, with the one-way valve received in the receiving space of the secondary air valve, heat dissipation can be improved while the one-way valve is protected against premature deterioration and carbon deposition caused by a high-temperature exhaust gas from the cylinder head. Thus, reliability as well as a service life of the one-way valve is effectively increased.

Abstract: A cooling structure for a continuous variation transmission system of an all-terrain vehicle which includes a radiator mounted at a front end of the vehicle and under a front body cover, a hood enclosing the radiator, a gearbox having an inlet and an outlet, the inlet being connected with an inlet conduit for drawing outside cool air into the gearbox, the outlet being connected with an exhaust conduit for discharging hot air from the gearbox, wherein the inlet conduit has an inlet end mounted between the hood and the front body cover and shielded by the hood and the front body cover, whereby the cooling structure can effectively prevent water, dirt and dust from entering the gearbox and are simple in construction and easy to assemble and maintain.

Abstract: A gear-shifting safety device is provided for an all-terrain vehicle (ATV), including a gear lever, a gear-shifting hub shaft, a gear-shifting gear set, and a reversing bar. An end of the gear-shifting hub forms a step on which a block is provided. The block and the step form a stop face therebetween. The reversing bar has an end forming a stop section that is positionable on the step and is selectively in abutting engagement with the stop face so that to change to the reversing position, the reversing bar must be first actuated to disengage the stop section thereof from the stop face, allowing the switching fork to move to the reversing position on a position chute of the gear-shifting hub, thereby eliminating the damage of accidentally switching to reversing during the forward movement of the vehicle.

Abstract: A cooling structure for a continuous variation transmission system of an all-terrain vehicle which includes a radiator mounted at a front end of the vehicle and under a front body cover, a hood enclosing the radiator, a gearbox having an inlet and an outlet, the inlet being connected with an inlet conduit for drawing outside cool air into the gearbox, the outlet being connected with an exhaust conduit for discharging hot air from the gearbox, wherein the inlet conduit has an inlet end mounted between the hood and the front body cover and shielded by the hood and the front body cover, whereby the cooling structure can effectively prevent water, dirt and dust from entering the gearbox and are simple in construction and easy to assemble and maintain.

Abstract: A gearshift fork assembly is mounted on a shaft for a gearshift fork in a gearbox of a motor vehicle and comprises a hollow body, a gearshift fork, a sleeve and a resilient member. The hollow body is put on the shaft and comprises a first engagement section formed on its outer surface. The gearshift fork comprises a ring at one end, and the ring is put on one end of the hollow body and includes a second engagement section on its inner surface. The second engagement section is adapted to mesh with the first engagement section. The sleeve is put on the other end of the hollow body and comprises a third engagement section formed on its inner surface. The third engagement section is adapted to mesh with the first engagement section. The resilient member is biased between the ring and the sleeve.

Abstract: A vehicle transmission includes a crankshaft extending through a seal cover and into an oil-storing end portion of a driven shaft. The oil-storing end portion of the driven shaft defines a lubricating space filled with lubricating oil, and extends into the seal cover. A unidirectional clutch is disposed in the lubricating space and outwardly of the seal cover.

Abstract: A vehicle transmission includes a crankshaft extending through a seal cover and into an oil-storing end portion of a driven shaft. The oil-storing end portion of the driven shaft defines a lubricating space filled with lubricating oil, and extends into the seal cover. A unidirectional clutch is disposed in the lubricating space and outwardly of the seal cover.

Abstract: A park-position mechanism includes a selector mechanism that includes a cam mounted on a selector hub shaft, a pat gear mounted on a main shaft and corresponding in position to the cam, a park arm arranged between the cam and the park gear. The park arm has a holed base fit over a stud that rotates and supports the park arm in a crankshaft case. A torsion spring is arranged between the park arm and the crankshaft case with ends attached to the park arm and the crankshaft case respectively. The park arm has a driven section and an engaging section respectively extending from opposite sides of the holed base. The engaging section forms a projection. The driven section forms a hole in which a guide rod is received in an axially movable manner. The guide rod is engaged with the earn and is thus selectively driven by the cam to cause engagement of the projection of the engaging section with the park gear. A resilient member is arranged between the hole and the guide rod.

Abstract: An oil pump system is provided for a motorcycle, and includes at least one oil pump, a water pump, a drive shaft, a support frame, a drive gear, and an oil collector lid. The oil pump is supported by a crankshaft case and is coupled to the drive shaft. The drive shaft has an end section on which the drive gear is mounted. The drive gear is coupled to a crankshaft of an engine by a chain. The oil collector lid is arranged outside the drive gear. The water pump is coupled to the end of the drive shaft. Mechanical power is transmitted from the crankshaft, through the chain, to drive the drive gear and the drive shaft to also drive the water pump. The support frame is provided to rotatably support the drive shaft at a location spaced from the oil pump so as to form an enhanced support to the drive shaft and improve stability of operation and durability of the drive shaft.

Abstract: The present invention is to provide a gearshift fork assembly mounted on a shaft for gearshift fork in a gearbox of a motor vehicle and comprising a hollow body, a gearshift fork, a sleeve and a resilient member. The hollow body is put on the shaft and comprises a first engagement section formed on its outer surface. The gearshift fork comprises a ring at one end, the ring is put on one end of the hollow body and includes a second engagement section on its inner surface, the second engagement section is adapted to mesh with the first engagement section. The sleeve is put on the other end of the hollow body and comprises a third engagement section formed on its inner surface, the third engagement section is adapted to mesh with the first engagement section. The resilient member is biased between the ring and the sleeve.

Abstract: A gearbox device for a motor vehicle includes a box housing formed with a window, and an ultimate drive shaft extending through the box housing. A speed change gearing is disposed within the box housing, and includes a bevel gear set disposed in proximity to the window. The bevel gear set includes a driving bevel gear driven by a crankshaft, and a driven bevel gear sleeved removably on the ultimate drive shaft and meshing with the driving bevel gear. A removable cover is connected removably to the box housing for covering the window, and is removable from the box housing so that the bevel gear set is exposed within the window, thereby allowing for access to the bevel gear set via the window and, thus, adjustment, maintenance, repair, and replacement of the bevel gear set.

Abstract: A noise suppressing mechanism for balance gear system of an engine crankshaft is disclosed. The balance gear system includes a primary gear, a secondary gear, and a torsional spring and is fit on a balance shaft. The noise suppressing mechanism includes a circular flange formed on the primary gear and the secondary gear forms a central bore rotatably fit over the circular flange for free rotation about the circular flange with respect to the primary gear. The torsional spring is arranged between the primary and secondary gears. The primary gear forming a securing hole in which a stem section of a limiting pin is received and fixed. The secondary gear forms a through hole in which a head section of the limiting pin is accommodated with a gap formed between the head section and an inside diameter of the through hole. The gap allows for a limited angular shift of the secondary gear with respect to the primary gear.

Abstract: A noise suppressing mechanism for balance gear system of an engine crankshaft is disclosed. The balance gear system includes a primary gear, a secondary gear, and a torsional spring and is fit on a balance shaft. The noise suppressing mechanism includes a circular flange formed on the primary gear and the secondary gear forms a central bore rotatably fit over the circular flange for free rotation about the circular flange with respect to the primary gear. The torsional spring is arranged between the primary and secondary gears. The primary gear forming a securing hole in which a stem section of a limiting pin is received and fixed. The secondary gear forms a through hole in which a head section of the limiting pin is accommodated with a gap formed between the head section and an inside diameter of the through hole. The gap allows for a limited angular shift of the secondary gear with respect to the primary gear.

Abstract: A cooling structure for a continuous variation transmission system of an all-terrain vehicle which includes a radiator mounted at a front end of the vehicle and under a front body cover, a hood enclosing the radiator, a gearbox having an inlet and an outlet, the inlet being connected with an inlet conduit for drawing outside cool air into the gearbox, the outlet being connected with an exhaust conduit for discharging hot air from the gearbox, wherein the inlet conduit has an inlet end mounted between the hood and the front body cover and shielded by the hood and the front body cover, whereby the cooling structure can effectively prevent water, dirt and dust from entering the gearbox and are simple in construction and easy to assemble and maintain.

Abstract: Disclosed is a cooling mechanism for cooling a belt-based speed-change system of an engine. The engine has a crankshaft for output of power, and the crankshaft has an end coupled to a power generator and an opposite end extending into a transmission box and coupled to the belt-based speed-change system. A wet-type clutch is arranged between the belt-based speed-change system and the engine. The wet-type clutch has a clutch cover separating the clutch from the belt-based speed-change system. The transmission box forms an air inlet and an air outlet on front and rear sides thereof, respectively. An air guide chamber is formed inside the transmission box and defines an air collection chamber communicating with the air inlet. The clutch cover is mounted to and covers the air guide chamber and defines openings in communication with the air collection chamber.

Abstract: A pull-start engine includes a crankcase unit, a pull-start unit, a gearbox unit, and a lubricating unit. The crankcase unit includes a crankcase and a crankshaft. The gearbox unit includes a gearbox and a drive shaft. The pull-start unit is sleeved fixedly on the crankshaft. A surrounding wall of the pull-start unit has an inner wall surface formed with an annular inner slot communicated with a lubricant passage in the crankshaft, an outer wall surface formed with a through hole communicated with the inner slot, and two annular flanges flanking the through hole so as to define an annular outer slot therebetween. The lubricating unit includes an entrance passage formed in the crankcase and communicated with the outer slot, and a connecting passage formed in the crankcase and the gearbox and communicated with the outer slot and a lubricant passage in the drive shaft.