A transmission includes a first power transmitting path of gears that obtains odd number speeds and has an output part, a second power transmitting path of gears that obtains even number speeds and has an output part; a first gear shifting part incorporated in the first power transmitting path to obtain one of the odd number speeds, a second gear shafting part incorporated in the second power transmitting path to obtain one of the even number speeds, and a path shifting part that is arranged between the first and second power transmitting parts. The path shifting part shifts the first second power transmitting paths to output power to the output shaft.

A transmission is provided having a control module, an input member, an output member, four planetary gear sets, a plurality of interconnecting members, and a plurality of torque transmitting devices. Each of the planetary gear sets includes first, second and third members. The torque transmitting devices include clutches and brakes. The control module includes a control logic sequence for performing a coasting downshift of the transmission.

A multi-speed transmission including a plurality of planetary gearsets and a plurality of selective couplers to achieve at least eight forward speed ratios is disclosed. The plurality of planetary gearsets may include a first planetary gearset, a second planetary gearset, a third planetary gearset, and a fourth planetary gearset. The plurality of selective couplers may include a number of clutches and a number of brakes. The multi-speed transmission may have four planetary gearsets and six selective couplers. The six selective couplers may include two clutches and four brakes.

A constant mesh gearbox has five parallel rotational axes. The input and output axes are not aligned. Up to eight forward speeds are disclosed, with two very low ratios suitable for non-highway travel. The transmission is suitable for two and four wheel drive.

A method of controlling an automatic transmission is provided. The automatic transmission includes first and second frictional engageable elements and a hydraulic mechanism. The method includes controlling a first hydraulic pressure control valve of the first element to adjust hydraulic pressure to a given value in a first period in response to the gear shift command and increase the hydraulic pressure until first friction plates engaged in a second period, and a second hydraulic pressure control valve of the second element to pre-charge in response to the gear shift command, maintain the hydraulic pressure at a lower value than a highest target value immediately after the pre-charging, and increase the hydraulic pressure until second friction plates engaged immediately after the maintaining the pressure, a time length of the first period being shorter than a time length between a start of the pre-charging and a start of the increasing the pressure.

A method of controlling an automatic transmission is provided. The automatic transmission includes a piston having first and second surfaces opposite from each other, friction plates, engaging and disengaging hydraulic pressure chambers for supplying/discharging hydraulic pressure and directing the piston to push the friction plates to be engaged and disengaged, a hydraulic pressure control valve for supplying/discharging hydraulic pressure to/from the chambers, and first and second oil paths communicating the valve with the chambers. The second surface has a larger area for receiving hydraulic pressure than the first surface. The method includes controlling the disengaged friction plates to be engaged by adjusting the hydraulic pressure to a first pressure in a first period in response to a gear shift command and adjusting the hydraulic pressure to a second pressure in a second period. The first pressure is changed depending on a state of the automatic transmission.

A method of controlling an automatic transmission is provided. The automatic transmission includes a piston having first and second surfaces opposite from each other, friction plates, engaging and disengaging hydraulic pressure chambers for supplying hydraulic pressure and directing the piston to push the friction plates to be engaged and disengaged, a hydraulic pressure control valve for supplying and discharging hydraulic pressure to and from the chambers, and first and second oil paths communicating the valve with the chambers. The second surface has a larger area for receiving hydraulic pressure than that of the first surface. The method includes controlling the friction plates to change from the disengaged state to the engaged state. Controlling the friction plates includes adjusting the hydraulic pressure to a first instruction pressure in a first period in response to a gear shift command, and to a second instruction pressure in a second period.

A transmission is disclosed having an input member, an output member, a plurality of planetary gear sets, a plurality of interconnecting members and a plurality of torque-transmitting mechanisms including a one-way clutch. The plurality of planetary gear sets has first, second and third members. The input member is continuously interconnected with a member of the planetary gear sets. The output member is continuously interconnected with another member of the planetary gear sets. At least eight forward speeds and one reverse speed are produced by the selective engagement of the five torque-transmitting mechanisms.

A multi-stage planetary transmission for a bicycle or a pedelec includes a transmission input shaft (1), a transmission output shaft (2), and at least three planetary gear sets (VRS, VR1, VR2, RS1, RS2, NRS, NR1, NR2). A first planetary gear set (RS1) and a second planetary gear set (RS2) are configured as a main gear set and at least one further planetary gear set (VRS, VR1, VR2, NRS, NR1, NR2) is configured as a front-mounted gear set and/or as a rear-mounted gear set. At least three free-wheel clutches (F1, F2, F3, F4) and at least three brakes (B1, B2, B3, B4) are provided for implementing at least eight gears (G1, G2, G3, G4, G5, G6, G7, G8, G9, G10, G11, G12, G13, G14, G15, G16). Moreover, the multi-stage transmission may be a bottom bracket transmission. In addition, a bicycle or pedelec with the multi-stage transmission is proposed.

A tolerance ring is formed in an inner circumference of a clutch drum at a more forward position than a spline-fitted part in a forward direction during assembly of the clutch drum to a third sun gear; thus, the tolerance ring is located closer to an axial end of the clutch drum than to the spline-fitted part. Accordingly, it becomes easier to carry out grooving to form an annular groove for housing the tolerance ring therein in the inner circumference of the clutch drum, and thereby deterioration of machinability is suppressed.