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.

The invention relates to a shifting device for a motor vehicle transmission, comprising a first coupling component, a second coupling component rotatable about a transmission axis (A), an inner friction ring which has a conical surface on a radially outer face, an outer friction ring which has a conical surface on a radially inner face, and an intermediate friction ring which comprises a friction cone and is connected to the second coupling component for joint rotation with and for axial displacement with respect to the second coupling component, whilst the inner friction ring and the outer friction ring are connected to the first coupling component for joint rotation with and for axial displacement with respect to the first coupling component. The friction cone extends between the conical surfaces of the inner friction ring and outer friction ring, the coupling components being decoupled in the rotation direction in an axial starting position of the outer friction ring and being coupled in a frictional fit in the rotation direction in an axial frictional fit position of the outer friction ring. The intermediate friction ring has a C-shaped ring cross section extending peripherally in the circumferential direction, comprising a radially outer linear cone limb which forms the friction cone and comprises two substantially parallel conical friction surfaces, and comprising a radially inner linear axial limb which is integrally connected to the cone limb by a radial web.

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 transmission (G) is provided with four planetary gear sets (P1, P2, P3, P4), several shafts (W1-W8) and a first, second, third, fourth and fifth shift element (B1, B2, K1, K2, K3), the selective meshing of which brings about different transmission ratio relationships between a transmission input shaft (GW1) and a transmission output shaft (GW2). The second shift element (B2) and/or the fifth shift element (K3) is arranged, in a series at a sixth shift element (K4), in the power flow between the fifth shaft (W5) and a sun gear (So-P4) of the fourth planetary gear set (P4).

A planetary gear train of an automatic transmission for a vehicle may include an input shaft receiving torque of an engine, an output shaft outputting changed torque, a first planetary gear set, a second planetary gear set, a third planetary gear set, a fourth planetary gear set, a first rotation shaft selectively connected to a transmission housing, a second rotation shaft, a third rotation shaft selectively connected to the transmission housing, a fourth rotation shaft directly connected to the input shaft, a fifth rotation shaft selectively connected to the second rotation shaft, a sixth rotation shaft, a seventh rotation shaft selectively connected to the input shaft, and selectively connected to the fifth rotation shaft or the sixth rotation shaft, and an eighth rotation shaft directly connected to the output shaft.

A planetary gear train of an automatic transmission for vehicles may include an input shaft receiving torque of an engine, an output shaft outputting changed torque of the engine, a first planetary gear set, a second planetary gear set, a third planetary gear set, a fourth planetary gear set, a first shaft, a second rotation shaft, a third rotation shaft, a fourth rotation shaft selectively connected to the input shaft, a fifth rotation shaft selectively connected to the input shaft or selectively connected to the transmission housing, a sixth rotation shaft directly connected to the output shaft to be continuously operated as an output element, a seventh rotation shaft selectively connected to the transmission housing, an eighth rotation shaft selectively connected to the third rotation shaft, a ninth rotation shaft directly connected to the input shaft to be continuously operated as an input element, and six friction elements.

The present disclosure provides a multiple speed transmission having an input member, an output member, a plurality of planetary gearsets, a plurality of interconnecting members and a plurality of torque-transmitting mechanisms. Each of the plurality of planetary gearsets includes a sun gear, a ring gear, and a carrier member with pinion gears. The input member is continuously interconnected with at least one member of one of the plurality of planetary gear sets, and the output member is continuously interconnected with another member of one of the plurality of planetary gear sets. At least ten forward speeds and one reverse speed are achieved by the selective engagement of the plurality of torque-transmitting mechanisms.

Ten forward speeds and one or more reverse speed are achieved by a planetary gear train of an automatic transmission for a vehicle including an input shaft, an output shaft, four planetary gear sets respectively having three rotational elements, and six control elements for selectively interconnecting the rotational elements and a transmission housing.

A planetary gear train of an automatic transmission for the vehicle may include: an input shaft receiving torque of an engine; an output shaft outputting torque; a first planetary gear set including first, second, and third rotation elements; a second planetary gear set including fourth, fifth, and sixth rotation elements; a third planetary gear set including seventh, eighth, and ninth rotation elements; and a fourth planetary gear set including tenth, eleventh, and twelfth rotation elements.