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A gear shift shock reducing apparatus for a hydraulic control system of an automotive automatic transmission comprising a pressure reducing valve operatively disposed between an actuating means of a frictional unit and a manual selector valve to produce a pressure which is not higher than a line pre

A gear shift shock reducing apparatus for a hydraulic control system of an automotive automatic transmission comprising a pressure reducing valve operatively disposed between an actuating means of a frictional unit and a manual selector valve to produce a pressure which is not higher than a line pressure. The pressure reducing valve is responsive to a kickdown condition and is rendered inoperative.

대표청구항 ▼

A gear shift shock reducing apparatus of a hydraulic control system for an automatic transmission including a driving member operatively connected to the output shaft of an engine of an automotive vehicle, a driven member, and frictional units having fluid operated actuating means selectively made o

A gear shift shock reducing apparatus of a hydraulic control system for an automatic transmission including a driving member operatively connected to the output shaft of an engine of an automotive vehicle, a driven member, and frictional units having fluid operated actuating means selectively made operative and inoperative for producing a plurality of gear ratios between the driving and driven members, comprising: means for generating a line fluid pressure; means for generating a kickdown fluid pressure under a kickdown condition; a manual valve provided operatively between said line fluid pressure generating means and the respective fluid operated actuating means of the frictional units; a shift valve provided operatively between said manual valve and at least one of the fluid operated actuating means of the frictional units, said shift valve having a valve spool movable into a position providing communication between said line fluid pressure generating means through said manual valve and said at least one of the fluid operated actuating means; and a pressure reducing valve provided operatively between said at least one of the fluid operated actuating means and said manual valve and having a valve member movable into a position providing communication between said at least one of the fluid operated actuating means and said manual valve through said shift valve, said pressure reducing valve communicating with said kickdown fluid pressure generating means for producing an actuating fluid pressure which is not higher than said line fluid pressure in response to the absence of said kickdown fluid pressure, said valve member of said fluid pressure reducing valve including a first pressure-acting area which is selectively exposed to said actuating said pressure to which said at least one of the fluid operated actuating means is selectively exposed and a second pressure-acting area, opposite to said first pressure-acting area, which is selectively exposed to said kickdown fluid pressure, said valve member of said pressure reducing valve being held in said position providing communication between said at least one of the fluid operated actuating means and said manual valve through said shift valve when said second pressure-acting area is exposed to said kickdown fluid pressure.