Hydraulic pressure control apparatus of automatic transmission
AssigneeFuji Jukogyo Kabushiki Kaisha
InventorHosei Suzuki
Life of this patent
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Abstract
Hydraulic pressure regulated by a first pressure control valve is supplied to an electromagnetic changeover valve. The electromagnetic changeover valve changes over the hydraulic pressure between a low & reverse passage communicating with a low & reverse brake and a high clutch passage communicating with a high clutch, thereby a simultaneous engagement of the low & reverse brake and the high clutch can be avoided and further the simplification of the hydraulic control apparatus of an automatic transmission can be realized.
Claims5
A hydraulic control apparatus of a multiple speed ratio automatic transmission having an input shaft from an engine, an output shaft and gear sets interposed between said input and output shafts and adapted to provide a plurality of speed ratios, said hydraulic control apparatus including friction elements selectively operative to establish said plurality of speed ratios, a shift lever manually operated by a driver and a manual valve interconnected with said shift lever for engaging or disengaging said friction elements, the improved apparatus comprising:
- a first friction element engaged when said shift lever is positioned at “1” (a first gear hold) range;
- a second friction element engaged when gearing of said gear sets is at a second gear position;
- a third friction element engaged when gearing of said gear sets is at a third gear position;
- a fourth friction element engaged when gearing of said gear sets is at least at a first gear position;
- a first pressure control valve for regulating a hydraulic pressure to be supplied to said first and third friction elements;
- a second pressure control valve for regulating a hydraulic pressure to be supplied to said second friction element;
- a reverse friction element engaged only when said shift lever is positioned at an “R” (reverse) range;
- and
- an electromagnetic hydraulic passage changeover valve provided between said first pressure control valve and said first and third friction elements for selectively changing over hydraulic passages between said first friction element and said third friction element, said electromagnetic hydraulic passage changeover valve having a spool integrated with a solenoid.
A hydraulic control apparatus of a multiple speed ratio automatic transmission having gear sets adapted to provide a plurality of speed ratios, said hydraulic control apparatus including friction elements selectively operative to establish said plurality of speed ratios, a shift lever manually operated by a driver and a manual valve interconnected with said shift lever for engaging or disengaging said friction elements, the improved apparatus comprising:
- a first friction element engaged when said shift lever is positioned at “1” (a first gear hold) range;
- a second friction element engaged when gearing of said gear sets is at a second gear position;
- a third friction element engaged when gearing of said gear sets is at a third gear position;
- a fourth friction element engaged when gearing of said gear sets is at least at a first gear position;
- a first pressure control valve for regulating a hydraulic pressure to be supplied to said first and third friction elements;
- a second pressure control valve for regulating a hydraulic pressure to be supplied to said second friction element;
- a reverse friction element engaged only when said shift lever is positioned at an “R” (reverse) range;
- and
- an electromagnetic hydraulic passage changeover valve provided between said first pressure control valve and said first and third friction elements for selectively changing over hydraulic passages between said first friction element and said third friction element,
- wherein the hydraulic pressure supplied to said first, second, and third friction elements is regulated using only said first and second pressure control valves.
Dependencies are inferred from the claim text.