Abstract: A speed changing device includes a control unit (60) that: has a manual mode in which a clutch is engaged and disengaged by operating a clutch lever (4b) and an automatic mode in which the clutch is engaged and disengaged without the clutch lever (4b) being operated and is able to change a setting to the manual mode and the automatic mode; and is configured to signal mode misrecognition when it is determined that mode misrecognition has occurred.

Abstract: A speed changing device includes a control unit (60) that: has a manual mode in which a clutch is engaged and disengaged by operating a clutch lever (4b) and an automatic mode in which the clutch is engaged and disengaged without the clutch lever (4b) being operated and is able to change a setting to the manual mode and the automatic mode; and is configured to signal mode misrecognition when it is determined that mode misrecognition has occurred.

Abstract: A transmission for a vehicle is provided which prevents generation of a speed change shock at the time of starting the vehicle from a neutral condition. In the transmission, hydraulic clutches are each put into a connected state according to an action of an oil pressure, and a plurality of selectively engageable speed-stage gear trains are provided so that a neutral condition can be obtained. At the time of shifting from the neutral condition, where the oil pressures in hydraulic clutches are in a lowered state, to a starting condition in which a starting gear train is engaged, pressure in the hydraulic clutch corresponding to the starting gear train is controlled by a control valve, so that the oil pressure in the hydraulic clutch is maintained in the lowered state during and immediately after a shifting operation, and is subsequently increased in response to complete engagement of the starting gear train.

Abstract: A lubricating device for a power unit includes an oil pan, an oil tank being separated from the oil pan, a scavenging pump for circulating the received oil of the oil pan to the oil tank, and a feed pump to feeding oil stored in the oil tank to the engine and the transmission, wherein an oil reservoir for storing a certain amount of oil to immerse a lower part of a clutch that connects and disconnects a transmission route between the engine and the transmission is provided in a power unit case, and a first overflow passage is provided in the oil tank such that when the stored oil in the oil tank is increased beyond a first level, the first overflow passage allows the increased oil to overflow into the oil reservoir side.

Abstract: The vehicle driving force transmission structure of a power unit can include a main transmission having a transmission shaft group and parallel to a crankshaft and provided in a crankcase on the side of the crankshaft. The transmission structure can also include a large rotational body provided at an end of the crankshaft, and an auxiliary transmission provided as a separate body from and connecting to the main transmission. The auxiliary transmission has a transmission shaft group parallel to the transmission shaft group of the main transmission and disposed so as to form a periphery of the large rotational body. The auxiliary transmission includes a transmission driving mechanism disposed below the large rotational body.

Abstract: A shift drum structure for a drum-type transmission in which a shift fork moving on a shift fork shaft in an axial direction while guided by a guide groove in response to a turn of a shift drum, changes speeds by sliding a shifter member on a transmission driving shaft pivotally supporting a transmission gear, the shift drum. The shift drum includes a cylindrical drum main body and drum spindles projecting outward from drum end walls on the respective two sides of the drum main body, and the guide groove formed in an outer peripheral surface of the drum main body in a circumferential direction, wherein in the shift drum, a work groove is formed in the outer peripheral surface of the drum main body from one end surface to an opposite end surface of the drum main body, or to the guide groove near the opposite end surface.

Abstract: The vehicle driving force transmission structure of a power unit can include a main transmission having a transmission shaft group and parallel to a crankshaft and provided in a crankcase on the side of the crankshaft. The transmission structure can also include a large rotational body provided at an end of the crankshaft, and an auxiliary transmission provided as a separate body from and connecting to the main transmission. The auxiliary transmission has a transmission shaft group parallel to the transmission shaft group of the main transmission and disposed so as to form a periphery of the large rotational body. The auxiliary transmission includes a transmission driving mechanism disposed below the large rotational body.

Abstract: A shift drum structure for a drum-type transmission in which a shift fork moving on a shift fork shaft in an axial direction while guided by a guide groove in response to a turn of a shift drum, changes speeds by sliding a shifter member on a transmission driving shaft pivotally supporting a transmission gear, the shift drum. The shift drum includes a cylindrical drum main body and drum spindles projecting outward from drum end walls on the respective two sides of the drum main body, and the guide groove formed in an outer peripheral surface of the drum main body in a circumferential direction, wherein in the shift drum, a work groove is formed in the outer peripheral surface of the drum main body from one end surface to an opposite end surface of the drum main body, or to the guide groove near the opposite end surface.

Abstract: A lubricating device for a power unit includes an oil pan, an oil tank being separated from the oil pan, a scavenging pump for circulating the received oil of the oil pan to the oil tank, and a feed pump to feeding oil stored in the oil tank to the engine and the transmission, wherein an oil reservoir for storing a certain amount of oil to immerse a lower part of a clutch that connects and disconnects a transmission route between the engine and the transmission is provided in a power unit case, and a first overflow passage is provided in the oil tank such that when the stored oil in the oil tank is increased beyond a first level, the first overflow passage allows the increased oil to overflow into the oil reservoir side.

Abstract: A shift controller with a first clutch CL1 that connects/disconnects the torque to a first main shaft and a second clutch CL2 connects/disconnects the torque to a second main shaft. A transmission is configured so that dog clutches DC1, DC2 for first speed and for second speed are engaged in a predetermined turned position P1-2 of a shift drum. A linear solenoid valve that supplies clutch oil pressure, a shift solenoid that switches a destination of the supply oil pressure between both clutches and a controller that controls the supply oil pressure and the turning of the shift drum are provided. The controller supplies predetermined oil pressure P1 to the CL2 in neutral, switches the destination of supply oil pressure to the CL1 when the shift drum is turned to P1-2 according to a shift instruction to engage gears and supplies maximum oil pressure P3 to the CL1 in predetermined time ta.

Abstract: A transmission assembly includes a shift drum operable to rotate in first and second directions. The shift drum includes a common speed change position, where both a fastest forward gear and a reverse gear are capable of becoming engaged, in such a manner that a reverse stopper arm fits at a first end of a reverse cam groove formed on the shift drum. When the shift drum is rotated in the second rotation direction, opposite to the first direction, from a state where the reverse gear is engaged, the reverse stopper arm surmounts the outer periphery of the shift drum from the first end of the reverse cam groove, without requiring the application of an external force thereto, so as to become detached and to move towards a second end of the reverse cam groove.

Abstract: A shift controller for a motor vehicle includes an electric motor configured to rotate a shift drum associated with a transmission. An oil temperature sensor is configured to detect temperature of lubricating oil for the transmission. A controller is configured to control the electric motor. The controller controls the electric motor to operate in a preset first motor duty until a first predetermined time elapses after operation of the electric motor is started when the shift drum is turned from a first predetermined position to a second predetermined position. The controller is also configured to operate the electric motor in a second motor duty calculated based upon oil temperature after the first predetermined time elapses.

Abstract: In a clutch device wherein a plurality of clutch plates are relatively non-rotatably engaged with a clutch outer, a plurality of clutch disks disposed alternately with the clutch plates are relatively non-rotatably engaged with a clutch inner, and an end plate disposed so that the clutch plates and the clutch disks are disposed between itself and a piston slidably fitted in the clutch outer is relatively non-rotatably and axially movably supported on the clutch outer in the manner of being restricted in movement toward one end side in the axial direction, to prevent the clutch inner from coming out of position at the time of assembling the clutch device into position, thereby to enhance workability in the assembling operation, and to prevent the clutch inner from generating a collision sound by colliding against other member than the component members of the clutch device when the clutch is disengaged.

Abstract: A transmission for a vehicle in which changing a shift position is achieved by sliding a shifter. In sliding the shifter to change the established condition of gear trains respectively corresponding to a plurality of shift positions, the transmission of power from an engine to a main shaft is cut off. A feed mechanism for sliding the shifter is configured to reduce the sliding speed of the shifter in a neutral condition, or to cause the sliding operation of the shifter to have a single stopping action in the neutral condition during the sliding operation of the shifter in changing the established condition of the gear trains. The resulting configuration reduces the engagement noise when changing the shift position.

Abstract: A vehicular transmission includes a shift drum center with a plurality of gear train establishment notches disposed, equally spaced apart from each other, on the outer periphery thereof. The gear train establishment notches establish a specific gear train selected from among a plurality of gear trains by selectively engaging a drum stopper arm therein. The shift drum center further includes half neutral notches to be engaged with the drum stopper arm. The half neutral notches are disposed on the outer periphery of the shift drum center and at a central portion between each pair of the gear train establishment notches, respectively. The resulting configuration effectively suppresses an engagement noise during changing of a gear position through a sliding motion of a shifter.

Abstract: A vehicular transmission for an internal combustion engine includes lead grooves disposed on an outer periphery of a shift drum having communication portions connecting a pair of gear train establishment portions extending circumferentially along the shift drum. The communication portions include half neutral portions formed at a center thereof, extending circumferentially along the shift drum. The resulting configuration suppresses an engagement noise to a minimum during changing of a gear position through a sliding motion of a shifter.

Abstract: A transmission M of a vehicular power transmission system has a first shifting part and a second shifting part which shift a power of an internal combustion engine, a first shift clutch transmitting and interrupting the power to the first shifting part, and a second shift clutch transmitting and interrupting the power to the second shifting part. A start clutch transmitting and interrupting the power to the first shift clutch and the second shift clutch is constructed of a centrifugal clutch C having a clutch shoe. The resulting configuration provides a vehicular power transmission system which has excellent efficiency of power transmission and durability, as well as being capable of being manufactured at low cost, and being capable of relieving a start shock.

Abstract: A vehicle transmission includes first and second main shafts that enable switching of power transmission from an engine; a counter shaft connected to a drive wheel; and gear trains with a plurality of shift stages provided between each of the first and second main shafts and the counter shaft. The vehicle transmission also includes shifters which switch between engagement with and disengagement from a gear constituting part of each of the gear trains so as to switch the established states of the gear trains, and to prevent, during running at the most frequently used shift stage, the occurrence of gear rattle produced by a gear train other than the gear train with such a shift stage. With this configuration, in the running state of using a particular gear train with the highest frequency of the established states among the gear trains, the gear trains, excluding the particular gear train, are in the non-established state.

Abstract: An automatic transmission assembly having a transmission unit including a plurality of gear pairs, a shift drum, a pair of clutches; and a controller. The controller performs a preliminary upshifting action in advance for angularly moving the shift drum depending on a next gear position in an upshifting direction while rotary drive power is being maintained at a given gear position, and when an upshifting command is output, the controller engages one of the clutches simultaneously with the command. When a downshifting command is output, the controller performs a preliminary downshifting action in advance based on the downshifting command. The partially neutral positions are provided between predetermined angular positions on the shift drum for temporarily reducing the angular speed of the shift drum when the shift drum is being angularly rotated.

Abstract: A gear transmission permits an increased flexibility in the layout of shift gears and reduces the axial size of the transmission by providing an engaging portion on a specific one of the shift gears. The gear transmission includes a main shaft having drive gears, a countershaft having driven gears adapted to be respectively driven by the drive gears to set predetermined shift positions, and shifters engageable with specific gears of the drive gears and the driven gears. The specific gears respectively have engaging portions for engaging the shifters, whereby the main shaft rotationally drives the countershaft through any one of the shifters and any one of the specific gears at any one of the predetermined shift positions. Of the engaging portions, the outer diameter of the engaging portion is larger than the outer diameter of a toothed portion of the drive gear as one of the specific gears.