Control device for automatic transmission
AssigneeAisin-Warner Kabushiki Kaisha
InventorMutsumi Kawamoto
Life of this patent
Estimating the term…
Abstract
The control device for automatic transmissions with an overdrive mechanism engages the brake of the overdrive mechanism while the shift control valve of the hydraulic control device is in the N-position (neutral), so that when the shift lever is shifted from the N-position to the D-position or R-position, the overdrive mechanism is momentarily set for overdrive thereby reducing shocks upon manually shifting.
Claims7
A control device for an automatic transmission having a gear system provided with a plurality of friction engaging elements for providing torque corresponding to a plurality of gear ratios including an overdrive ratio to a transmission output shaft, comprising:
- a manual shift valve for manually selecting neutral, forward and reverse drive positions;
- an electric control circuit comprising signal generating means for generating an electric signal in accordance with the vehicle running conditions and in accordance with the position selected for the manual shift valve, and a logic circuit for receiving said electric signal and generating an electric output signal corresponding to one of the gear ratios;
- and
- a hydraulic control system comprising
- a source of hydraulic pressure,
- hydraulic servo means to operate said plurality of friction engaging elements,
- a shift valve operable between first and second positions for receiving hydraulic pressure from said hydraulic pressure source and supplying hydraulic pressure to said hydraulic servo means through fluid passages, and
- a solenoid valve to control the position of said shift valve in response to the electric output signal of said electric control circuit,
- whereby said friction engaging elements associated with the overdrive ratio are engaged to provide torque to the transmission output shaft for a predetermined period of time when said manual shift lever is manually shifted from neutral to the forward or reverse drive position.
Dependencies are inferred from the claim text.