Vehicle automatic transmission control apparatus with fail-safe arrangement

• US 20060030446A1
• Filed: 08/04/2005
• Published: 02/09/2006
• Est. Priority Date: 08/05/2004
• Status: Active Grant

• Current Assignee: Aisin AW Company Limited (Aisin Corp.), Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Aisin AW Company Limited (Aisin Corp.), Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Noda, Kazuyuki, Kondo, Masami, Fujimine, Takuya, Nozaki, Kazutoshi
• Granted Patent: US 7,320,657 B2
• Time in Patent Office: Days
• US Class Current: 475/119
• CPC Class Codes: F16H 2061/0209 with independent solenoid valves modulating the pressure individually for each clutch or brake
• CPC Class Codes: F16H 2061/1232 Bringing the control into a predefined state, e.g. giving priority to particular actuators or gear ratios
• CPC Class Codes: F16H 2061/1264 Hydraulic parts of the controller, e.g. a sticking valve or clogged channel
• CPC Class Codes: F16H 2200/006 the gear ratios comprising eight forward speeds
• CPC Class Codes: F16H 2200/2007 with two sets of orbital gears
• CPC Class Codes: F16H 2200/2023 using a Ravigneaux set with 4 connections
• CPC Class Codes: F16H 61/12 Detecting malfunction or potential malfunction, e.g. fail safe in control of hydrostatic gearing F16H61/4192; Circumventing or fixing failures
• CPC Class Codes: F16H 61/686 with orbital gears

Abstract

A control apparatus for controlling a vehicle automatic transmission including (i) a first coupling device to be engaged for establishing an emergency gear position and (ii) a second coupling device to be released for establishing the emergency gear position. The control apparatus includes: (a) first and second controller valves for controlling the respective first and second coupling devices; and (b) a fail-safe valve having (b-1) a first output port connected to a drain port of the first controller valve, (b-2) a first input port to which a working fluid is input, (b-3) a first drain port for draining the working fluid, (b-4) a second output port connected to an input port of the second controller valve, (b-5) a second input port to which the working fluid is input, and (b-6) a second drain port for draining the working fluid.

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.

2. The control apparatus according to claim 1,

wherein said fail-safe valve is switchable between a normal communication state and an emergency communication state,

wherein when said fail-safe valve is placed in said normal communication state, said first output port and said first drain port are held in communication with each other, said first input port is not held in communication with said first output port, said second output port and said second input port are held in communication with each other, and said second drain port is not held in communication with said second output port,

and wherein when said fail-safe valve is placed in said emergency communication state, said first output port and said first input port are held in communication with each other, said first drain port is not held in communication with said first output port, said second output port and said second drain port are held in communication with each other, and said second input port is not held in communication with said second output port.

3. The control apparatus according to claim 1,

wherein each of said plurality of coupling-device controller valves is provided by an electro-magnetically operated valve,

said control apparatus further comprising:

a power supply failure detector detecting a power supply failure disabling sufficient supply of an electric power to said plurality of coupling-device controller valves; and

a fail-safe-valve switcher operable when said power supply failure is detected by said power supply failure detector, to place said fail-safe valve in an emergency communication state establishing said emergency gear position.

4. The control apparatus according to claim 3,

wherein each of said plurality of controller valves, when being energized, is placed in an open state in which said output port and said input port are held in communication with each other while said drain port is not held in communication with said output port,

and wherein each of said plurality of controller valves, when being de-energized, is placed in a closed state in which said output port are said drain port are held in communication with each other while said input port is not held in communication with said output port.

5. The control apparatus according to claim 4, wherein when said fail-safe valve is placed in said emergency communication state, said first output port and said first input port are held in communication with each other, so as to serve as an emergency output port and an emergency input port, for allowing supply of the working fluid to each of said at least one first coupling device through said emergency input and output ports of said fail-safe valve and said drain and output ports of said first controller valve, so that said at least one first coupling device is engaged for establishing said emergency gear position.

6. The control apparatus according to claim 5,

wherein when said fail-safe valve is placed in said emergency communication state, said second drain port is held in communication with said second output port, so as to serve as an emergency drain port, for allowing draining of the working fluid discharged from each of said at least one second coupling device through said output and input ports of said second controller valve and said second output and emergency drain ports of said fail-safe valve, so that said at least one second coupling device is released for establishing said emergency gear position.

7. The control apparatus according to claim 3,

wherein said fail-safe-valve switcher is provided by a spool-position controller valve selectively allowing and inhibiting application of hydraulic pressure to a spool of said fail-safe valve in a direction causing said fail-safe valve to be placed in said emergency communication state,

wherein said spool-position controller valve is provided by an electro-magnetically operated valve,

wherein said spool-position controller valve, when being energized, is placed in a closed state inhibiting said application of the hydraulic pressure, so that said fail-safe valve is not placed in said emergency communication state,

and wherein said spool-position controller valve, when being de-energized, is placed in an open state allowing said application of the hydraulic pressure, so that said fail-safe valve is placed in said emergency communication state.

8. The control apparatus according to claim 7,

wherein said spool-position controller valve serves as said power supply failure detector, and detects said power supply failure when said spool-position controller valve is not energized,

and wherein said spool-position controller valve serving as said power supply failure detector, upon detection of said power supply failure, outputs said hydraulic pressure, as a signal representative of said power supply failure, which is applied to said spool of said fail-safe valve.

9. The control apparatus according to claim 7, wherein said fail-safe valve includes a biaser biasing said spool of said fail-sage valve in a direction opposite to said direction causing said fail-safe valve to be placed in said emergency communication state.

10. The control apparatus according to claim 1,

wherein said fail-safe valve includes a spool which is movable to change a combination of communicated ones of said first output, input and drain ports which are held in communication with each other and also a combination of communicated ones of said second output, input and drain ports which are held in communication with each other,

and wherein said spool of said fail-safe valve is provided by a single member.