HYDRAULIC PRESSURE CONTROLLER FOR CHANGING-OVER DOUBLE PARALLEL MOTION CONNECTING CLUTCH OR BRAKE

摘要

Two concurrently operated hydraulic brakes of an automotive transmission, actuated in an intermediate-speed ("second gear") position, are filled under the control of a slide valve whose slider in a normal position admits fluid at high rate to both brakes and thereafter assumes an unstable throttling position in which the fluid pressure gradually builds up in them to a value causing an associated plunger to return the slider to normal. One of the brakes, which is only unidirectionally effective, remains actuated also upon an upshift into a high-speed position ("third gear") whereas the other, bidirectionally effective brake is released upon such upshift under the control of a shift valve which cuts off the fluid flow to the latter brake and establishes a drainage path therefor by passing the slide valve.