280 results about "Automatic transmission system" patented technology

An electric actuator for an automatic transmission includes an adapter to transmit rotary motion between the adapter and the transmission. An electric motor has an output shaft operably connected the adapter by a gear set which includes a ring gear. A release mechanism includes a solenoid which selectively moves a lock member. In a first position, the lock member engages the ring gear to lock the ring gear so that the adapter is rotated by rotary motion of the output shaft and the adapter rotates to a predetermined zone about a desired gear position. In a second position, the lock member is out of engagement with the ring gear to permit rotation of the ring gear so that the adapter is rotated by internal forces of the transmission and the adapter automatically self-aligns to the exact desired gear position when the adapter is within the predetermined zone.

The hydraulic pressure control mechanism for a change to a higher gear in a motor vehicle automatic transmission system with a series of hydraulic friction clutches has a first system (102) to determine whether the upward gear change command has been started while there is no pressure on the accelerator pedal, a second system (104) to determine whether a factor modifying an automatic transmission input torque has been generated, and a correction command system to correct the engagement pressure of the predetermined hydraulic friction clutch in conformity with the modification factor. The mechanism also has a computer (106) to calculate the gear selection value on the basis of the vehicle's actual speed, and a system to determine a differential value between the rotational speed of the transmission input shaft and synchronised speed.

A closed loop shift control apparatus and method based on friction element load controls a torque transfer phase when shifting from a low gear configuration to a high gear configuration for an automatic transmission system. When pressure actuated friction elements are selectively engaged and released to establish torque flow paths in the transmission, measurements or estimates of torsional load exerted on the off-going friction element are used to predict the optimal off-going friction element release timing for achieving a consistent shift feel. The ideal timing to release the off-going friction element is uniquely defined when torque load exerted onto the off-going friction element becomes substantially zero. An on-coming clutch engagement process is controlled by a closed loop control based on measurements or estimates of on-coming clutch torque capacity for a constant shift feel under dynamically changing conditions.

An SBW storage of an SBW controller stores a rotational angular position of an output shaft of an electric actuator. When the SBW controller is restarted due to instantaneous power interruption, the SBW controller maintains and uses the current angular position of the output shaft, which is stored in the SBW storage device, as a latest rotational angular position of the output shaft that is used to drive a shift range change mechanism upon satisfaction of the following conditions: the electric motor has not been driven before the instantaneous power interruption, and the current rotational angular position of the output shaft, which is stored in the SBW storage device, is not destroyed.

An automatic transmission system for a vehicle having a plurality of drive gears mounted on an input shaft, a plurality of driven gears mounted on an output shaft and meshing with the drive gears, a torque converter disposed between a crankshaft of an engine and the input shaft, synchromesh mechanisms for synchronously engaging the drive gears with the driven gears and a shift controller for automatically actuating the synchromesh mechanisms so as to obtain a required gear ratio, includes a lock-up clutch incorporated in the torque converter for connecting a turbine shaft of the torque converter with the crankshaft, an electronically controlled throttle valve for automatically operating to reduce a rotation speed of the crank shaft when the gear is shifted, a bypass clutch for transmitting torque from the input shaft to the output shaft when the gear is shifted while the electronically controlled throttle valve operates to reduce a rotation speed of the crankshaft, an input clutch provided between an output element of the torque converter and the input shaft for selectively controlling a torque transmission from the crankshaft to the input shaft when the gear is shifted, and a brake mechanism provided on an impeller shell of the torque converter for additionally reducing a rotational speed of the crankshaft while the electronically controlled throttle valve operates to reduce a rotational speed of the crankshaft.

A control apparatus includes a shift-pressure learning correction controlling section configured to perform a shift-pressure learning correction in which a physical quantity representing a progress of shift is measured at a time of a current downshift, and in which an engagement command pressure for a friction element is corrected at a time of a next downshift on the basis of a divergence between the measured physical quantity and a target physical quantity; a shift-torque increase controlling section configured to perform a torque increase control in which a command for temporarily increasing torque of a drive source starts to be outputted when a start estimation timing of torque phase has just come during a transition period given between start and end of the downshift; and a learning convergence judging section configured to judge whether the shift-pressure learning correction has converged.

A driving force margin of a vehicle is calculated on the basis of an engine load, vehicle speed, travel resistance and estimated uphill gradient. A gear is determined on the basis of predetermined gear shifting characteristics at least from the vehicle speed and the engine load in an automatic shift mode. Automatic down shift is generated in the case where the vehicle speed becomes lower than vehicle speed on an automatic down shift vehicle speed table set up in accordance with the gear when the operation is switched from the automatic shift mode to a manual shift mode. The automatic down shift vehicle speed table is corrected so as to shift an automatic down shift line to a high vehicle speed side or low vehicle speed side in accordance with the magnitude of the calculated driving force margin of the vehicle.

A closed loop shift control apparatus and method based on estimated torque in friction elements controls a torque transfer phase when shifting from a low gear configuration to a high gear configuration for an automatic transmission system. When pressure actuated friction elements are selectively engaged and released to establish torque flow paths in the transmission, estimates of torsional load exerted on the off-going friction element are used to predict the optimal off-going friction element release timing for achieving a consistent shift feel. The estimated torque is preferably calculated by using estimated torque signals generated as a function of speed measurements represented either the engine speed and turbine output speed or transmission output speed and wheel speed under dynamically changing conditions.