US3738182A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Control system for an automatic transmission
Assignee: Toyota Motor Corp
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Filing: 1971-07-19
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Granted: 1973-06-12
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Expires: 1991-07-19
Abstract
Abstract In a vehicle automatic transmission wherein shift points are set through electrical controls, a control system for relieving a shock which occurs when the transmission shift lever is shifted from the neutral N position to the reverse R position or from the parking P position to the R position.
Inventors
- 👤 S Kubo
- 👤 M Hashimoto
- 👤 T Akashi
- 👤 C Hayashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 01:08
CPC Classifications
F; F16; F16H; F16H47/00; F16H47/06; F16H47/08
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
198 words
A vehicle automatic transmission comprising a speed change gear, and frictionally engageable means with hydraulic servos for accomplishing the required gear changing operations of the speed change gear, an automatic transmission control system comprising: a hydraulic control system for controlling a supply of fluid under hydraulic pressure to said frictionally engageable means; a vehicle driving condition responsive electrical signal generating means; shift control means responsive to said vehicle driving condition responsive electric signal to generate an electrical signal for actuating said hydraulic control system; shift position signal generating means for detecting shift gear positions, and shock control signal generating means for generating an electrical signal having predetermined duration including a logic means for combining the electric signal generated by said shift position signal generating means when operated upon establishment of the reverse gear position, and the electric signal corresponding to a predetermined condition of said vehicle driving condition responsive electric signal generating means, the electric signal generated by said shock control signal generating means actuating said hydraulic control system to control the supply of liquid under hydraulic pressure to said frictionally engageable means for shifting the automatic transmission to the reverse gear position, thereby reducing gear shifting shock.
Claim 2
Dependent Claim
198 words
A vehicle automatic transmission comprising a speed change gear, and frictionally engageable means with hydraulic servos for accomplishing the required gear changing operations of the speed change gear, an automatic transmission control system comprising: a hydraulic control system for controlling a supply of fluid under hydraulic pressure to said frictionally engageable means; a vehicle driving condition responsive electrical signal generating means; shift control means responsive to said vehicle driving condition responsive electric signal to generate an electrical signal for actuating said hydraulic control system; shift position signal generating means for detecting shift gear positions, and shock control signal generating means for generating an electrical signal having predetermined duration including a logic means for combining the electric signal generated by said shift position signal generating means when operated upon establishment of the reverse gear position, and the electric signal corresponding to a predetermined condition of said vehicle driving condition responsive electric signal generating means, the electric signal generated by said shock control signal generating means actuating said hydraulic control system to control the supply of liquid under hydraulic pressure to said frictionally engageable means for shifting the automatic transmission to the reverse gear position, thereby reducing gear shifting shock.
Claim 3
Dependent Claim
93 words
The control system according to claim 1, wherein said vehicle driving condition responsive electrical signal generating means comprises: low engine load signal generating means, and said shock control signal generating means responds to a low engine load signal from said low engine load signal generating means to produce an electrical signal for said predetermined duration only when the reverse gear position is established under a low engine load, said shock control signal generating means terminating said electric signal at an instant when an engine load reaches a predetermined magnitude within said predetermined duration.
Claim 4
Dependent Claim
194 words
A control system according to claim 1, wherein said hydraulic pressure supply control means comprises a shift control valve for supplying a hydraulic pressure to the hydraulic servo means for changing the transmission to the reverse gear, a pressure regulator valve for regulating the valve of said hydraulic pressure, pressure lines for connecting said hydraulic servo means with said shift control valve, orifices for controlling the flow rate of the hydraulic pressure supplied to said hydraulic servo means, and a pressure line inter-connecting said pressure regulator valve and said shift control valve for supplying a hydraulic pressure into an oil chamber of said pressure regulator valve to reduce the hydraulic pressure regulated by said pressure regulator valve, whereby in response to the electrical signal generated by said shock control signal generating means said shift control valve is actuated upon shifting into the reverse gear so that the rising characteristic of the hydraulic pressure supplied to said hydraulic servo means for engaging said reverse gear is modified by virtue of a reduction in the regulated hydraulic pressure and the flow rate control effected by said orifices, thereby lessening the shock during the gear changing operation.
Claim 5
Dependent Claim
77 words
The control system according to claim 1 wherein said logic means includes: a first delay circuit producing an output at a selected time after an input from the shift position signal generating a second delay circuit producing an output at a different selected time after receipt of the electric signal indicative of the predetermined driving condition; said delay circuits producing the signal of the shock control circuit for a selected duration for actuating said hydraulic control system.
Claim 6
Dependent Claim
82 words
The vehicle automatic transmission system of claim 3 wherein each of said delay means includes a gate circuit for producing an output in response to its selected input and energy storage means including a capacitor for delaying the output of each of said gates a selected amount in accordance with its energy storage characteristic; and AND gate means for combining the two delayed signals during their simultaneous occurrence to produce a square wave signal corresponding to said shock control circuit electrical signal.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-06-11 | 1976-12-11 | 1977-06-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-06-11 | 1980-12-11 | 1981-06-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-06-11 | 1984-12-11 | 1985-06-12 | $7700.00 | Window Closed / Lapsed |