US 7,320,657 B2 | ||
Vehicle automatic transmission control apparatus with fail-safe arrangement | ||
Kazutoshi Nozaki, Nisshin (Japan); Masami Kondo, Toyota (Japan); Kazuyuki Noda, Handa (Japan); and Takuya Fujimine, Hamamatsu (Japan) | ||
Assigned to Toyota Jidosha Kabushiki Kaisha, Toyota-shi (Japan); and Aisin AW Co., Ltd., Anjo-shi (Japan) | ||
Filed on Aug. 04, 2005, as Appl. No. 11/196,417. | ||
Claims priority of application No. 2004-229916 (JP), filed on Aug. 05, 2004. | ||
Prior Publication US 2006/0030446 A1, Feb. 09, 2006 | ||
Int. Cl. F16H 31/00 (2006.01) |
U.S. Cl. 475—119 | 10 Claims |
1. A control apparatus for controlling a vehicle automatic transmission including a plurality of hydraulically operated frictional
coupling devices operable to selectively establish a plurality of gear positions having respective different speed ratios,
wherein said plurality of hydraulically operated frictional coupling devices include (i) at least one first coupling device
that is to be engaged for establishing an emergency gear position which is a predetermined one of the plurality of gear positions,
and (ii) at least one second coupling device that is to be released for establishing said emergency gear position, said control
apparatus comprising:
(a) a plurality of coupling-device controller valves operable to control flow of a pressurized working fluid that is to be
supplied to the respective hydraulically operated frictional coupling devices; and
(b) a fail-safe valve,
wherein each of said plurality of coupling-device controller valves has:
(a-1) an input port to which the pressurized working fluid is to be input;
(a-2) an output port from which the working fluid is to be output to a corresponding one of the hydraulically operated frictional
coupling devices;
(a-3) a drain port from which the working fluid is to be drained; and
(a-4) a spool which is movable to change a combination of communicated ones of said input, output and drain ports which are
held in communication with each other, such that said corresponding one of the hydraulically operated frictional coupling
devices is selectively engaged and released depending upon said combination of the communicated ports,
and wherein said fail-safe valve has:
(b-1) a first output port connected to said drain port of a first controller valve which is one of said controller valves
controlling flow of the working fluid supplied to each of said at least one first coupling device;
(b-2) a first input port communicable with said first output port such that the working fluid supplied to said first input
port can be supplied to said drain port of said first controller valve through said first output port;
(b-3) a first drain port communicable with said first output port such that the working fluid discharged to said first output
port from said each of said at least one first coupling device can be drained through said first drain port;
(b-4) a second output port connected to said input port of a second controller valve which is one of said controller valves
controlling flow of the working fluid supplied to each of said at least one second coupling device;
(b-5) a second input port communicable with said second output port such that the pressurized working fluid supplied to said
second input port can be supplied to said input port of said second controller valve through said second output port; and
(b-6) a second drain port communicable with said second output port such that the working fluid discharged to said second
output port from said each of said at least one second coupling device can be drained through said second drain port.
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