Patent US3851547A successfully refreshed from Google Patents.
US3851547A
Expired / Lapsed
US
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Hydraulic circuits for controlling automatic gear boxes
Assignee: Peugeot & Renault
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Filing: 1973-04-13
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Granted: 1974-12-03
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Expires: 1993-04-13
Abstract
Abstract A hydraulic circuit for controlling an automatic gear box comprises an output regulation valve controlled by a hydraulic distributor and a pressure regulation valve. The output regulation valve is connected to means for controlling clutch and brake devices of the gear box, and the pressure regulation valve is controlled by a pilot valve actuated in dependence upon the speed of an engine driving the gear box. The pressure regulation valve provides a path between the outlet of a pump, which feeds fluid to the circuit, and a fluid reservoir, the path being connected by a duct to the hydraulic distributor and to the output regulating valve. A pressure drop is provided across the outlet path, for example by a calibrated orifice whereby the hydraulic distributor and the output regulation valve are controlled in response to the speed of the engine.
Inventors
- 👤 J Piret
- 👤 P Quemerais
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 15:40
CPC Classifications
F; F16; F16H; F16H61/00; F16H2710/00; F16H2710/16; F16H2710/20; Y; Y10; Y10S; Y10S74/00; Y10S74/01
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
197 words
In a hydraulic circuit for controlling an automatic gear box in which selection of the drive ratio is effected by selective actuation of clutch means and brake means, hydraulic control means associated with the clutch means and the brake means, an output regulation valve, said valve being connected to the control means, a hydraulic distributor, a pressure regulation valve, the hydraulic distributor and the pressure regulation valve being operative to control the output regulation valve, a pilot valve responsive to the value of the vacuum in the inlet manifold of an engine driving the gear box, and operative to control the pressure regulation valve, a reservoir for hydraulic fluid, pump means operative to feed fluid from the reservoir, said pump means having an outlet, the pressure regulation valve defining an outlet path from the pump outlet to the reservoir, duct means connecting the output path to the hydraulic distributor and to the output regulating valve, and a calibrated orifice located at the outlet of the regulation valve to create a pressure drop in the said outlet path such that the hydraulic distributor and the output regulating valve are controlled in response to the speed of the engine.
Claim 2
Dependent Claim
197 words
In a hydraulic circuit for controlling an automatic gear box in which selection of the drive ratio is effected by selective actuation of clutch means and brake means, hydraulic control means associated with the clutch means and the brake means, an output regulation valve, said valve being connected to the control means, a hydraulic distributor, a pressure regulation valve, the hydraulic distributor and the pressure regulation valve being operative to control the output regulation valve, a pilot valve responsive to the value of the vacuum in the inlet manifold of an engine driving the gear box, and operative to control the pressure regulation valve, a reservoir for hydraulic fluid, pump means operative to feed fluid from the reservoir, said pump means having an outlet, the pressure regulation valve defining an outlet path from the pump outlet to the reservoir, duct means connecting the output path to the hydraulic distributor and to the output regulating valve, and a calibrated orifice located at the outlet of the regulation valve to create a pressure drop in the said outlet path such that the hydraulic distributor and the output regulating valve are controlled in response to the speed of the engine.
Claim 3
Dependent Claim
128 words
A circuit as claimed in claim 1, wherein the pressure regulation valve comprises means defining a first chamber, the first chamber being connected to the pilot valve, a slide, spring means, said spring means exerting a force on the slide in one direction, the pressure in the first chamber exerting a force on the slide in the said one direction and the delivery pressure of the pump means exerting a force on the slide in a direction opposite to the said one direction, means defining a second chamber, the second chamber communicating with the hydraulic distributor, and means defining a third chamber, the third chamber providing the said outlet path from the pump outlet to the reservoir, and the slide being movable within the second and third chambers.
Claim 4
Dependent Claim
77 words
A circuit as claimed in claim 2, wherein the pressure regulation valve further comprises means defining an outlet orifice from the third chamber, the said duct means communicating with the outlet orifice, and the pressure within the duct means being a pilot pressure, the hydraulic distributor comprising, a slide, and the output regulating valve comprising, a slide, the slide of the hydraulic distributor and the slide of the output regulating valve being subjected to the pilot pressure.
Claim 5
Dependent Claim
73 words
A circuit as claimed in claim 3, wherein the slide of the hydraulic distributor is movable into a selected one of two positions under the action of the pilot pressure, in one of the said two positions, the slide placing the second chamber at a pressure corresponding to the outlet pressure of the pump means, and in the other of the said two positions, the slide causing the second chamber to be depressurized.
References Cited (Backward Citations)
US3643527A
Cited
US3699994A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-12-02 | 1978-06-03 | 1978-12-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-02 | 1982-06-03 | 1982-12-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-02 | 1986-06-03 | 1986-12-03 | $7700.00 | Window Closed / Lapsed |