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US 4,729,265 AGranted
Shift shock suppression arrangement for automotive automatic transmission
AssigneeNissan Motor Co., Ltd.
InventorKazuhiko Sugano
Life of this patent
Estimating the term…
Abstract
In order to obviate shift shock during shifting between second and third gears in a transmission wherein a front clutch and a band brake having apply and release chambers, an accumulator is connected to the circuit via which line pressure is supplied from a 2-3 shift valve in a manner that the engagement/release of the two friction elements is staged in a manner that reduces sharp fluctuations in the output shaft torque.
Claims8
In a transmission for an automotive vehicle:
- a first friction element, said first friction element having a first chamber which when supplied with hydraulic pressure causes said first friction element to assume an engaged condition;
- a second friction element, said second friction element having a second chamber which when supplied with hydraulic pressure induces said second friction element to assume a released condition;
- said transmission being arranged so that a first speed ratio is produced when said first and second friction elements are released and engaged respectively, and a second speed ratio is produced when said first and second friction elements are engaged and released respectively;
- a shift valve, said shift valve having a valve element which establishes communication between a source of hydraulic pressure and a port when in an upshift position and communication between the port and a drain when in a downshift position;
- a fluid circuit which interconnects said port and said first and second chambers;
- an accumulator for reducing shift shock having a third chamber in fluid communication with said fluid circuit;
- and
- a flow restrictor fluidly disposed in said fluid circuit between said port and said second chamber.
5 more elements
Dependencies are inferred from the claim text.