Abstract: A clutch apparatus includes a clutch outer member for supporting friction discs, which are nonrotatable relative to the clutch outer member, and are axially slidable along a clutch axis; a clutch inner member for supporting clutch discs, which are nonrotatable relative to the clutch inner member, and are axially slidable along the clutch axis, and a pressure plate having a deep recess for accommodating a clutch spring engaged with the clutch inner member. The deep recess includes a bottom portion having a spring seat for receiving the clutch spring, and a partially cylindrical shape wall portion having an axis parallel to the clutch axis. The wall portion is oriented towards the clutch axis. The deep recess has a communicating portion formed therein for establishing the communication between the inner and outer surfaces of the wall portion so as to discharge oil towards the friction and clutch discs during operation.

Abstract: An internal combustion engine for reducing the amount of bubbles contained in the circulated oil without reducing the ground clearance of the engine. A crankcase is provided therein with an oil suction passage makes an oil pump and an end part of a bottom wall of an oil sump chamber communicate with each other, passes between the oil sump chamber and a hanger boss, and has a lowest part located below the bottom wall of the oil sump chamber.

Abstract: A shift drive device with a shift arm having one end secured to a shift spindle with a guide hole for receiving a pin, provide to project therefrom, inserted therethrough and engaged therewith. A turn-restriction hole receives a restriction pin provided on a transmission case. A space that is needed for turning the shift arm is reduced. A turn-restriction hole is provided in a shift arm so as to be disposed on a straight line connecting an axial line of a shift spindle with the center of a guide hole.

Abstract: A clutch apparatus includes a clutch outer member for supporting friction discs, which are nonrotatable relative to the clutch outer member, and are axially slidable along a clutch axis; a clutch inner member for supporting clutch discs, which are nonrotatable relative to the clutch inner member, and are axially slidable along the clutch axis, and a pressure plate having a deep recess for accommodating a clutch spring engaged with the clutch inner member. The deep recess includes a bottom portion having a spring seat for receiving the clutch spring, and a partially cylindrical shape wall portion having an axis parallel to the clutch axis. The wall portion is oriented towards the clutch axis. The deep recess has a communicating portion formed therein for establishing the communication between the inner and outer surfaces of the wall portion so as to discharge oil towards the friction and clutch discs during operation of the clutch apparatus.

Abstract: An internal combustion engine for reducing the amount of bubbles contained in the circulated oil without reducing the ground clearance of the engine. A crankcase is provided therein with an oil suction passage makes an oil pump and an end part of a bottom wall of an oil sump chamber communicate with each other, passes between the oil sump chamber and a hanger boss, and has a lowest part located below the bottom wall of the oil sump chamber.

Abstract: A shift drive device with a shift arm having one end secured to a shift spindle with a guide hole for receiving a pin, provide to project therefrom, inserted therethrough and engaged therewith. A turn-restriction hole receives a restriction pin provided on a transmission case. A space that is needed for turning the shift arm is reduced. A turn-restriction hole is provided in a shift arm so as to be disposed on a straight line connecting an axial line of a shift spindle with the center of a guide hole.

Abstract: To improve the operating performance of a chain. A bicycle transmission includes an alignment guide located between a drive sprocket and a transmission sprocket cluster for aligning a stagnant chain. The alignment guide consists of a guide roller having an outer circumferential surface for guiding the stagnant part of the chain in a way to align it. The outer circumferential surface has, in the axial direction, a large diameter portion on the side of a transmission sprocket with the smallest outside diameter, and a small diameter portion on the side of a transmission sprocket with the largest outside diameter, which is smaller in diameter than the large diameter portion. While the chain is not stagnant, the chain, wound around a transmission sprocket, contacts the small diameter portion.

Abstract: The two-wheel/four-wheel drive switching device including a switching unit provided in either a power transmitting mechanism interposed between an engine and front wheels or a power transmitting mechanism interposed between the engine and rear wheels for switching between the continuation and interruption of power transmission in the power transmitting mechanism, and a control unit for controlling the switching unit. The control unit detects a drive current supplied to the switching unit and performs variable duty control to maintain the drive current at a given value. As a result, the two-wheel/four-wheel drive switching device reduces the generation of noise and greatly suppresses the consumption of power.

Abstract: A two-wheel-drive/four-wheel-drive switching system for a vehicle wherein noise is reduced and a state of drive can be securely indicated. A two-wheel-drive/four-wheel-drive switching system for a vehicle is provided with a switching unit provided to either of power transmission mechanisms connecting an engine and front wheels, and the engine and rear wheels via final reduction gear units for enabling or disabling the transmission of power in the power transmission mechanism. An indication control member is provided for detecting that the transmission of power is made in the power transmission mechanism and illuminates an indicator wherein the indication control means detects a phase difference in revolutions between a pair of final reduction gear units and illuminates or turns off the indicator when the phase difference is in a predetermined range.

Abstract: The two-wheel/four-wheel drive switching device including a switching unit provided in either a power transmitting mechanism interposed between an engine and front wheels or a power transmitting mechanism interposed between the engine and rear wheels for switching between the continuation and interruption of power transmission in the power transmitting mechanism, and a control unit for controlling the switching unit. The control unit detects a drive current supplied to the switching unit and performs variable duty control to maintain the drive current at a given value. As a result, the two-wheel/four-wheel drive switching device reduces the generation of noise and greatly suppresses the consumption of power.

Abstract: A two-wheel-drive/four-wheel-drive switching system for a vehicle wherein noise is reduced and a state of drive can be securely indicated. A two-wheel-drive/four-wheel-drive switching system for a vehicle is provided with a switching unit provided to either of power transmission mechanisms connecting an engine and front wheels, and the engine and rear wheels via final reduction gear units for enabling or disabling the transmission of power in the power transmission mechanism. An indication control member is provided for detecting that the transmission of power is made in the power transmission mechanism and illuminates an indicator wherein the indication control means detects a phase difference in revolutions between a pair of final reduction gear units and illuminates or turns off the indicator when the phase difference is in a predetermined range.

Abstract: A limited-slip differential includes a differential case having a two-piece structure formed by a cup-shaped case body and an end cap attached to an open end of the cup-shaped case body. The limited-slip differential having such two-piece differential case has a small number of parts, is easy to assemble and can be manufactured efficiently at a low cost, as compared to a conventional limited-slip differential having a three-piece differential case.

Abstract: To reduce the size and weight of an oil tank for a dry sump type lubricating system. A separate oil tank of a dry sump type lubricating system is mounted on the front surface of a front case cover constituting part of a crankcase divided into front and rear parts. An effective volume portion, in which oil supplied from the crankcase side via scavenging pumps and cooled by an oil cooler is contained, is provided in the oil tank. The bottom portion of the effective volume portion is connected to a feed pump on the crankcase side via an outlet side passage. A tank side pipe portion extending rearwardly through the oil tank is integrally provided at a portion of the oil tank higher than the oil level in the oil tank. The tank side pipe portion is connected to a crankcase side pipe portion integrally provided on an upper portion of the front case cover to form an overflow passage.

Abstract: A breather structure for a reduction gear in which a plurality of stop ribs are disposed within a housing. The stop ribs are disposed at nonuniform distances between successive ribs in order to prevent oil from entering a breather chamber of the housing. The relative spacing between successive ribs allows the breather structure to prevent oil traveling at varying speeds from entering the breather chamber. The ribs have an upper surface which is disposed at declining, or obtuse, angles with respect to an interior of the housing, and a lower surface which acts to receive oil rising from a bottom of the housing.

Abstract: In a saddle seat type motor vehicle for use on uneven ground and including a front final assembly provided between left and right front wheels, the front final assembly provides the left and right front wheels with driving torques differentiated at a predetermined ratio when the wheels rotates at different speeds. When the motor vehicle turns, large driving torque is supplied to inner wheels rotating at low speeds compared with outer wheels rotating at high speeds. This enables the motor vehicle to turn effectively and to reduce steering effort.

Abstract: A differential mechanism comprises a differential case assembly having a casing body connected to a source of drive force and a cap member coupled with the casing body to cover one opened end of the casing body, a plurality of input blocks housed in the case assembly and being movable circumferentially of the case assembly in correspondence with rotation of the casing body, and a pair of output cam members for clamping the input blocks relatively slidably and being independently rotatable owing to a frictional force produced with respect to each of the input blocks to thereby initiate a differential motion on an output side of the differential mechanism. The input blocks are provided in at least two different types and having projected portions. The projected portions of the input blocks of one type have a first upper end width while the projected portions of the input blocks of another type have a second upper end width different from the first upper end width.

Abstract: To reduce the size and weight of an oil tank for a dry sump type lubricating system. A separate oil tank of a dry sump type lubricating system is mounted on the front surface of a front case cover constituting part of a crankcase divided into front and rear parts. An effective volume portion, in which oil supplied from the crankcase side via scavenging pumps and cooled by an oil cooler is contained, is provided in the oil tank. The bottom portion of the effective volume portion is connected to a feed pump on the crankcase side via an outlet side passage. A tank side pipe portion extending rearwardly through the oil tank is integrally provided at a portion of the oil tank higher than the oil level in the oil tank. The tank side pipe portion is connected to a crankcase side pipe portion integrally provided on an upper portion of the front case cover to form an overflow passage.