Assembly for a synchronization unit of a variable ratio gear transmission. Assembly has a synchronizer ring and a friction ring. The friction ring has a friction surface and an installation surface and the synchronizer ring has a contact surface directed toward the installation surface. To allow a high efficiency of the synchronizing unit and simultaneously a functionally safe and comfortable operation of the variable ratio gear transmission, the synchronizer ring and the friction ring are configured and arranged such that the geometrical shape of the installation surface of the friction ring differs from the geometrical shape of the contact surface of the synchronizer ring in a relief state of a synchronizing process; and that the geometrical shape of the installation surface of the friction ring corresponds to the geometrical shape of the contact surface of the synchronizer ring in a load state of the synchronizing process.

Drive systems or powertrains including transmissions for electric and hybrid electric vehicles are provided. In some embodiments, dynamic, 2-position linear motor, one-way clutches are provided. In other embodiments, 3-position linear motor, 2-way clutches are provided. In a fixed speed ratio operating mode of an electric vehicle powertrain, torque values for two electric motors are determined by control logic to optimize overall efficiency of the motors. In a fixed torque ratio operating mode of the powertrain, speed values for the two motors are determined to optimize overall efficiency. A hybrid electric powertrain of at least one embodiment uses the optimized electric vehicle powertrain, an engine and the one-way and 2-way clutches to obtain a highly optimized hybrid powertrain.

A shift control apparatus of an automatic transmission includes: an input detecting unit configured to detect a real rotational speed of the input shaft; an output detecting unit configured to detect a real rotational speed of the output shaft; an estimating unit configured to estimate an estimated rotational speed of the input shaft, which corresponds to a shift request, by multiplying the real rotational speed of the output shaft by a target gear ratio; and a control unit configured to control the rotation of the input shaft based on a detection result from the input detecting unit. The control unit controls the rotation of the input shaft such that an upper-limiting rotational speed of a variation in real rotational speed of the input shaft is lower than the estimated rotational speed.

A shift control apparatus of an automatic transmission includes: an input detecting unit configured to detect a real rotational speed of the input shaft; an output detecting unit configured to detect a real rotational speed of the output shaft; an estimating unit configured to estimate an estimated rotational speed of the input shaft, which corresponds to a shift request, by multiplying the real rotational speed of the output shaft by a target gear ratio; and a control unit configured to control the rotation of the input shaft based on a detection result from the input detecting unit. The control unit controls the rotation of the input shaft such that an upper-limiting rotational speed of a variation in real rotational speed of the input shaft is lower than the estimated rotational speed.

Synchronizer ring made of deep-drawable sheet metal. The ring includes a ring-shaped sheet metal body having a conical section arranged between a wall and a hub surface. One or more radially outwardly projecting guide elements are defined by radially outwardly projecting tapered indentations integrally formed with the ring-shaped sheet metal body. The wall is located at a largest conical diameter side of the ring-shaped sheet metal body and extends substantially perpendicular to a ring body axis. Gear teeth are arranged on a radially outer end of the wall. The one or more guide elements are configured to provide centering guidance relative to a hollow cylindrical surface of a synchronizer ring hub.

Provided is a synchronizer device and method for a manual transmission, having a sliding sleeve which includes an internal toothing having sliding sleeve teeth, a clutch body, the clutch body having an external toothing having a multitude of clutch body teeth for internal toothing of the sliding sleeve to engage therein, and a synchronizer unit. The clutch body teeth at the axial tooth ends adjacent the sliding sleeve and/or at least some of the sliding sleeve teeth at the axial tooth ends adjacent the clutch body each include at least one convex end face which extends in the circumferential direction from a root point adjacent to a tooth flank of the respective tooth via an axially protruding apex portion as far as to a root point adjoining an opposite tooth.

Provided is a synchronizer device and method for a manual transmission, having a sliding sleeve which includes an internal toothing having sliding sleeve teeth, a clutch body, the clutch body having an external toothing having a multitude of clutch body teeth for internal toothing of the sliding sleeve to engage therein, and a synchronizer unit. The clutch body teeth at the axial tooth ends adjacent the sliding sleeve and/or at least some of the sliding sleeve teeth at the axial tooth ends adjacent the clutch body each include at least one convex end face which extends in the circumferential direction from a root point adjacent to a tooth flank of the respective tooth via an axially protruding apex portion as far as to a root point adjoining an opposite tooth.

A shift control method for a DCT vehicle, which adjusts a time required to shift gears through clutch control in a DCT. The shift control method includes controlling a release-side dutch such that the release-side dutch is partially disengaged by a controller when gear shifting is initiated in a state in which an accelerator pedal is not pressed, performing synchronization control by partially applying an apply-side dutch torque in an initial stage of synchronization such that an engine rotational speed follows and synchronizes an apply-side input shaft speed, and partially applying a release-side dutch torque in a last stage of synchronization by the controller, and performing torque hand-over control such that an apply-side clutch is engaged while the release-side clutch is disengaged by the controller, after performing the synchronization control.

A shift control method for a DCT vehicle, which adjusts a time required to shift gears through clutch control in a DCT. The shift control method includes controlling a release-side dutch such that the release-side dutch is partially disengaged by a controller when gear shifting is initiated in a state in which an accelerator pedal is not pressed, performing synchronization control by partially applying an apply-side dutch torque in an initial stage of synchronization such that an engine rotational speed follows and synchronizes an apply-side input shaft speed, and partially applying a release-side dutch torque in a last stage of synchronization by the controller, and performing torque hand-over control such that an apply-side clutch is engaged while the release-side clutch is disengaged by the controller, after performing the synchronization control.

A module for a system for driving and synchronizing a countershaft of a transmission gearbox. The module includes a coupling device having an input element intended to be rotationally coupled to a reversible electric machine and an output element intended to be rotationally coupled to the countershaft. The coupling device has a coupled state in which the clutch device is able to transmit torque between the input element and the output element and an uncoupled state in which the input element and the output element are uncoupled. Also included is a lock-up device which has a lock-up state in which said lock-up device blocks the rotation of the input element of the clutch device, and a released state in which said lock-up device allows the input element to rotate.