Rotary valve for automatic transmission

A rotary valve for an automatic transmission comprising:

• a spool rotatably received within a valve housing and driven by an actuator for selectively supplying hydraulic pressure from a hydraulic pressure source to each of a plurality of frictionally engaging elements through said spool;
• a central oil passage formed in said spool and extending along an axis of rotation of said spool;
• pairs of radial oil passages formed in said spool and radially extending symmetrically about said central oil passage on respective diametrical lines;
• an oil supply port opened into an axial end of said central oil passage;
• a feed pipe connected to said hydraulic pressure source and connected to said central oil passage;
• and
• a bushing mounted between an outer periphery of said feed pipe and an inner periphery of said central oil passage in said spool.

A rotary valve for an automatic transmission, comprising a spool rotatably received within a valve housing and rotatively driven by an actuator for selectively supplying hydraulic pressure from a hydraulic pressure source to each of a plurality of frictionally engaging elements through said spool, wherein

• said rotary valve includes a first drain port communicatable with selected one of frictionally engaging elements of an automatic transmission when said spool is rotated from a predetermined position for permitting the supply of said hydraulic pressure to said selected frictionally engaging element to a position for permitting the supply of the hydraulic pressure to another of said frictional engaging element for a higher gear shift, and a second drain port communicatable with said selected frictionally engaging element, when the spool is rotated from said predetermined position to a position for permitting the supply of the hydraulic pressure to another of said frictionally engaging element for a lower gear shift, said first and second drain ports being provided independently from each other,
• wherein said rotary valve includes a central oil passage formed along an axis of rotation of said spool, and a plurality of radial oil passages even spaced along the axis of rotation of said spool;
• and a supply means for supplying hydraulic pressure from said hydraulic pressure source into one end of said central oil passage along an axis of said central oil passage.