Abstract: A twin-clutch transmission that can always effectively reduce gear shift shock and a collision sound even under the existence of variation attributed to component tolerance and change over the ages attributed to wear. A twin-clutch transmission calculates a rotational speed difference (|Na?Nb|) between an odd-stage main shaft rotational speed (Na) and an even-stage main shaft rotational speed (Nb) and learns synchronization start gear shift drive displacement (?s) detected by a gear shift drive displacement detecting unit at the timing at which the rotational speed difference (|Na?Nb|) reaches a predetermined synchronization start determination rotational speed difference (Ds) from gear shift start. The twin-clutch transmission controls an actuator on the basis of the learned synchronization start gear shift drive displacement (?s).

Abstract: A cylindrical shift drum is rotatable around a third rotational axis. The cylindrical shift drum includes at least one lead groove in an outer circumferential surface of the cylindrical shift drum. A shift fork shaft extending in parallel to the third rotational axis is disposed opposite to the outer circumferential surface. At least one shift fork includes a main portion slidably supported by the shift fork shaft and a pin portion rotatably supported by the main body portion. The main body portion includes a fork portion to be engaged with at least one shifter gear. The pin portion is inserted in one of the at least one lead groove. The cylindrical shift drum is to be rotated to guide the pin portion along the one of the at least one lead groove to move the at least one shift fork to shift the at least one shifter gear.

Abstract: A shift drum angle detecting device for a transmission includes shift forks, a shift drum, a first sensor shaft, a first angle sensor, a speed increasing mechanism, and a second angle sensor. The first angle sensor is to detect a rotational angle of the first sensor shaft to output a first output value based on the rotational angle. The speed increasing mechanism includes a speed increasing drive member, a speed increasing driven member, and a second sensor shaft. The second angle sensor is provided to the second sensor shaft to detect a rotational angle of the second sensor shaft and to output a second output value based on the rotational angle. A rotational angle of the shift drum is to be detected based on the first output value output from the first angle sensor and the second output value output from the second angle sensor.

Abstract: In a multiple plate clutch having a main spring which is provided between a clutch center fixed in an axial direction and a pressure plate displaceable in the axial direction and presses plural clutch plates in a clutch engagement direction, and a lifter plate for lifting the pressure plate in a clutch release direction, a sub spring for urging the pressure plate in the clutch engagement direction through the lifter plate is provided between the clutch center and the lifter plate, and the lifter plate is lifted by a predetermined amount or more to cut off the urging force of the sub spring to the pressure plate.

Abstract: A gearbox includes a transmission mechanism and a clutch system including plural clutches. The gearbox has a gear change mechanism that is interlocked with a change pedal shaft to which rotational force by operation of a shift pedal is transmitted and arbitrarily selects a transmission gear of the transmission mechanism to perform gear shift. An ECU can electronically control connection/disconnection of the clutch system according to a shift position of the gear change mechanism.

Abstract: An air bleeding valve includes an annular valve element for removing air from oil contained in a hydraulic circuit of a hydraulic tensioner and for suppressing the removal of the oil. An air bleeding valve body is fitted in an air bleeding valve accommodating hole formed in the hydraulic tensioner. A circumferential groove having a rectangular cross section is formed on an outer circumferential surface of the air bleeding valve body. The annular valve element having a rectangular cross section is fitted in the circumferential groove so as to be movable in an axial direction parallel to the axis of the annular valve element, and displaceable in a radial direction toward and away from the axis of the annular valve element. Such air bleeding valve removes air in a hydraulic circuit while suppressing the removal of oil in the hydraulic circuit during starting operation of an engine.

Abstract: A vehicle transmission wherein a single shift spindle is provided with a master arm to operate the transmission via an accumulation mechanism and a clutch lever to operate a clutch, capable of more reliably realizing disconnection of the clutch after the completion of accumulation necessary for a shift operation. A vehicle transmission includes a master arm provided on a shift spindle for transmitting a rotational force to a shift drum of a transmission to rotate and operate the shift drum with a clutch lever provided on the shift spindle, to operate the clutch. An accumulation mechanism is capable of accumulating the rotational force transmitted from the shift spindle to the master arm. The master arm and the clutch lever are interlocked with each other. A delay mechanism is provided that delays the clutch disconnection operation with the clutch lever before accumulation is completed between the shift spindle and the clutch.

Abstract: A primary drive gear 10 is configured so as to have its position changed, by mounting the primary drive gear 10 in an axial direction within a length range of a crankshaft so as to displace a toothed portion 12 of said primary drive gear 10 in the axial direction of said crankshaft in response to a boss portion 13 integrally provided on said toothed portion 12 of said primary drive gear 10 so that said primary drive gear 10 is registered with a position in the axial direction of the primary driven gear meshing with said primary drive gear 10.

Abstract: A clutch control system for a transmission for detecting if hydraulic control during shifting is not executed. A first clutch and a second clutch are switched from a disengagement state to an engagement state by receiving a predetermined pressure generated by a hydraulic pump. A transmission executes shifting to an adjacent gear step by operation of switching the engagement state of the first clutch and of the second clutch from one side to the other side. If an elapse time t from the start of clutch switching operation reaches a predetermined time and an input-output speed ratio which is a ratio between engine speed and counter shaft rotational number falls within a predetermined range corresponding to a gear step before shifting, the transmission control unit discontinues the clutch switching operation by stopping the supply of hydraulic pressure to the other side clutch to bring it into the disengagement state.

Abstract: A speed change controlling apparatus in which the mode of driving force transmission is depends upon the roll angle of a vehicle body. When a roll angle is within a range from a second roll angle, which corresponds to a full bank state, to a first roll angle, speed change operation is carried out by soft speed change control in which variation of the driving force with respect to time is smaller than that by normal speed change control. If the roll angle is within another range from the first roll angle to a third roll angle, then normal speed change is carried out and if the roll angle is within a further range from an uprightly standing state to the third roll angle, then speed change operation is executed by direct speed change. When the roll angle is greater than the second roll angle, speed change is inhibited.

Abstract: A cavity 135 having a closed end wall 135a facing an end of a rotational shaft 71 and receiving the end of the rotational shaft 71 therein is defined in an inner surface of a case cover 55 such that supply oil passages 125, 126 are open at inner circumferential surfaces of the cavity 135. At least one radial joint hole 138 is defined in an end portion of the rotational shaft 71 and extends radially of the rotational shaft 71, the radial joint hole 138 having an inner end connected to another oil passage 111 in the rotational shaft 71 than a particular oil passage 112 in the rotational shaft 71. The radial joint hole 138 is connected to a corresponding supply oil passage 125 of the supply oil passages 125, 126, in the cavity 135.

Abstract: A twin clutch controlling apparatus includes an ATM control unit for controlling a shift actuator and a clutch actuator and a shift pedal P for carrying out shifting request to the ATM control unit. When a shifting request by the shift pedal P is issued, the ATM control unit drives the shift actuator to change over the shift stage to a next stage gear irrespective of an operational amount of a clutch lever L and then causes the manual operation clutch capacity arithmetic operation value (tqcltmt) to correspond to a clutch capacity corresponding to the next stage gear using an operational amount of the clutch lever L that exceeds a predetermined value as a trigger. If a predetermined period of time elapses while the clutch lever L is not operated, then the shifting request is an erroneous operation and the shift stage is returned to an original gear.

Abstract: A saddle type vehicle having mounted thereon a power unit is provided with a twin clutch type transmission including a pair of main shafts and a pair of clutches along different axes, to enable a compact layout of axes and a reduction in size of the unit and its surroundings. The axis center (first main axis) of a first main shaft is disposed rearwardly of the axis center (crank axis) of a crankshaft and forwardly of the axis center (counter axis) of a counter shaft, whereas the axis center (second main axis) of a second main shaft is disposed rearwardly of the axis center (counter axis) of the counter shaft and forwardly of the axis center (pivot axis) of a pivot shaft.

Abstract: To achieve downsizing of a power unit and the vicinity thereof by permitting compact axial arrangement in a straddle-ride type vehicle on which the power unit having a twin-clutch type transmission is mounted. The transmission has a pair of main shafts with respective different axes and corresponding clutches. One of respective axial centers of the main shafts is disposed on one (above) of the sides with respect to a line and the other is disposed on the other side (below), the line connecting an axial center of the counter shaft with an axial center of a pivot shaft, as viewed in side elevation from the axial direction of the main shafts and counter shaft.

Abstract: In a vehicle power unit including a twin clutch type transmission that includes a pair of main shafts and clutches mounted on mutually different shafts, to enable compact shaft arrangements and to achieve a reduction in the size of the unit and the surrounding areas. Axial centers of a shift drum and a countershaft are disposed across a line that connects axial centers of main shafts in a side view as viewed from a direction of an axis of each of the main shafts and the countershaft.

Abstract: A clutch control device is provided for a clutch to connect and disconnect the transmission of a rotational drive force from a power source to a drive wheel in a vehicle. A clutch control unit is configured to control a control amount for said clutch. A drive wheel rotation start detector is configured to detect a start of rotation of said drive wheel. A control correction amount calculator is configured to calculate a control correction amount of said clutch based on a difference between the clutch control amount detected at the start of rotation of said drive wheel and a predetermined reference value. The clutch control unit is further configured to apply said control correction amount to the control amount for said clutch to control said clutch.

Abstract: In a transmission system for vehicles in which shift position changing drive means is coaxially connected to a shift drum selectively establishing a plurality of gear trains for respective gear steps capable of selective establishment in response to a turned position and a shift position sensor detects which one of the gear trains is being established, the number of component parts is reduced and assembly performance is enhanced while allowing for automatic gear shifting by use of a shift actuator.

Abstract: A lubricating oil passage 113 includes an upstream oil passage 113a defined coaxially in a rotational shaft 71 for supplying lubricating oil to lubricated parts and a downstream oil passage 113b connected to the upstream oil passage 113a for supplying lubricating oil to canceler chambers 97, 107. The downstream oil passage 113b may be smaller in diameter than the upstream oil passage 113a and having at least a portion extending parallel to the axis of the rotational shaft 71. Control oil passages 111, 112 which have axes parallel to the axis of the rotational shaft 71 are defined in the rotational shaft 71 such that at least a portion of the control oil passages 111, 112 is disposed in a range wherein the downstream oil passage 113b is provided in a direction along the axis of the rotational shaft 71.

Abstract: A twin clutch controlling apparatus includes an ATM control unit for controlling a shift actuator and a clutch actuator and a shift pedal P for carrying out shifting request to the ATM control unit. When a shifting request by the shift pedal P is issued, the ATM control unit drives the shift actuator to change over the shift stage to a next stage gear irrespective of an operational amount of a clutch lever L and then causes the manual operation clutch capacity arithmetic operation value (tqcltmt) to correspond to a clutch capacity corresponding to the next stage gear using an operational amount of the clutch lever L that exceeds a predetermined value as a trigger. If a predetermined period of time elapses while the clutch lever L is not operated, then the shifting request is an erroneous operation and the shift stage is returned to an original gear.

Abstract: A gearbox includes a transmission mechanism and a clutch system including plural clutches. The gearbox has a gear change mechanism that is interlocked with a change pedal shaft to which rotational force by operation of a shift pedal is transmitted and arbitrarily selects a transmission gear of the transmission mechanism to perform gear shift. An ECU can electronically control connection/disconnection of the clutch system according to a shift position of the gear change mechanism.