Patent US3871250A successfully refreshed from Google Patents.
US3871250A
Expired / Lapsed
US
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Hydraulic control circuit for vehicle automatic transmission
Assignee: Nissan Motor Co Ltd
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Filing: 1973-10-19
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Granted: 1975-03-18
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Expires: 1993-10-19
Abstract
Abstract A hydraulic control circuit for a vehicle automatic transmission is disclosed wherein a pressure regulating valve reduces the main supply pressure which engages and disengages the frictional elements of the transmission to avoid the shock experienced when the gear selector is moved into the Drive (D) range and when the throttle is closed during cruising in a low gear range. The main supply pressure is increased when the throttle is opened to insure adequate torque transmission to the vehicle driveshaft.
Inventors
- 👤 Toshiyuki Miyauchi
- 👤 Kunio Ohtsuka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 09:04
CPC Classifications
F; F16; F16H; F16H61/00; F16H61/0021; F16H61/02; F16H61/0202; F16H61/0251; F16H2061/026; F16H59/00; F16H59/14; F16H59/18; F16H59/22
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
209 words
In a hydraulic control circuit for a vehicle automAtic transmission of the type wherein a plurality of shift control valves selectively deliver hydraulic fluid to a plurality of frictional elements to cause engagement and disengagement of said frictional elements having a first pressure-regulating means and a throttle valve responsive to the vehicle engine load interposed between a main supply pump and the shift control valves, the improvements comprising: a. a second pressure regulating means having an inlet connected to an outlet of said first pressure regulating means, and an outlet, b. a third pressure regulating means having inlets connected to said second pressure regulating means outlet and said throttle valve, and an outlet connected to an inlet of said first pressure regulating means, c. means to control said second pressure regulating means in response to the position of the vehicle accelerator pedal such that when the pedal is in an idle position or returning to an idle position, said second pressure regulating means transmits hydraulic fluid through said third pressure regulating means to said first pressure regulating means to cause said first pressure regulating means to lower the pressure of the hydraulic fluid supplied to said shift control valves, and d. means to control said third pressure regulating means.
Claim 2
Dependent Claim
209 words
In a hydraulic control circuit for a vehicle automAtic transmission of the type wherein a plurality of shift control valves selectively deliver hydraulic fluid to a plurality of frictional elements to cause engagement and disengagement of said frictional elements having a first pressure-regulating means and a throttle valve responsive to the vehicle engine load interposed between a main supply pump and the shift control valves, the improvements comprising: a. a second pressure regulating means having an inlet connected to an outlet of said first pressure regulating means, and an outlet, b. a third pressure regulating means having inlets connected to said second pressure regulating means outlet and said throttle valve, and an outlet connected to an inlet of said first pressure regulating means, c. means to control said second pressure regulating means in response to the position of the vehicle accelerator pedal such that when the pedal is in an idle position or returning to an idle position, said second pressure regulating means transmits hydraulic fluid through said third pressure regulating means to said first pressure regulating means to cause said first pressure regulating means to lower the pressure of the hydraulic fluid supplied to said shift control valves, and d. means to control said third pressure regulating means.
Claim 3
Dependent Claim
102 words
The improved hydraulic control circuit of claim 1 wherein said means to control said second pressure regulating means comprises a. a solenoid having a plunger engagable with a port in said second pressure regulating means such that hydraulic fluid passes through said second pressure regulating means only when said plunger is not engaged with said port, and b. switch means electrically connected to said solenoid and mechanically connected to an accelerator pedal in said vehicle such that said switch causes said solenoid plunger to disengage said port as said accelerator pedal is in an idle position or returning to an idle position.
Claim 4
Dependent Claim
28 words
The improved hydraulic control circuit of claim 2 wherein said switch causes said solenoid plunger to become disengaged from said port when said accelerator pedal is fully depressed.
Claim 5
Dependent Claim
47 words
The improved hydraulic control circuit of claim 1 wherein said third pressure regulating control means is the throttle valve which causes said third pressure regulating means to shut off the flow of hydraulic fluid to said first pressure regulating means when the vehicle throttle is fully opened.
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) | 1978-03-17 | 1978-09-16 | 1979-03-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-17 | 1982-09-16 | 1983-03-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-17 | 1986-09-16 | 1987-03-18 | $7700.00 | Window Closed / Lapsed |