Patent US3672166A successfully refreshed from Google Patents.
US3672166A
Expired / Lapsed
US
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Variable ratio hydrostatic transmissions
Assignee: Sigma
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Filing: 1970-09-25
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Granted: 1972-06-27
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Expires: 1990-09-25
Abstract
Abstract The hydrostatic transmission comprises a hydraulic motor as well as a pump of which the cubic capacity is regulated by a mechanism sensitive to the pressure of a liquid. This liquid is supplied by a pressure regulator on the movable member of which act, in the sense tending to increase the pressure, a force increasing with the speed of the pump and, in reverse sense, a force increasing with the resistant couple applied to the motor and a force proportional to said pressure. The transmission is useful for automobiles.
Inventors
- 👤 Olivier Isaac
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 22:47
CPC Classifications
F; F04; F04B; F04B49/00; F04B49/002; F16; F16H; F16H61/00; F16H61/38; F16H61/40; F16H61/46; F16H61/462
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
233 words
Hydrostatic transmission comprising a generating machine driven by a motor; at least one receiver machine mechanically coupled to one driving member capable of being subjected to variAble external forces; two pipes arranged in a closed circuit between the generator and receiver machine; a mechanism adapted to vary the unit flow of the generator machine; control means for said mechanism sensitive to the pressure of a liquid; and an auxiliary circuit adapted to provide said liquid under a pressure varying in the same sense as the speed of the generator machine and in reverse sense to the value of the external forces, the assembly being such that whatever the value of the external forces, the torque absorbed by the generator machine is substantially equal to the torque which the motor that drives it can supply; said auxiliary circuit comprising a source of liquid under pressure connected to a pressure reducer having a movable member on which act, in the sense tending to increase the output pressure of the regulator, a force increasing with the speed of the generator machine and, in the opposite sense, a first force increasing with the value of the external forces, and a second force proportional to said output pressure, said control means being sensitive to said output pressure, said movable member being urgable, in addition, by a spring acting in the same sense as said first and second forces.
Claim 2
Dependent Claim
233 words
Hydrostatic transmission comprising a generating machine driven by a motor; at least one receiver machine mechanically coupled to one driving member capable of being subjected to variAble external forces; two pipes arranged in a closed circuit between the generator and receiver machine; a mechanism adapted to vary the unit flow of the generator machine; control means for said mechanism sensitive to the pressure of a liquid; and an auxiliary circuit adapted to provide said liquid under a pressure varying in the same sense as the speed of the generator machine and in reverse sense to the value of the external forces, the assembly being such that whatever the value of the external forces, the torque absorbed by the generator machine is substantially equal to the torque which the motor that drives it can supply; said auxiliary circuit comprising a source of liquid under pressure connected to a pressure reducer having a movable member on which act, in the sense tending to increase the output pressure of the regulator, a force increasing with the speed of the generator machine and, in the opposite sense, a first force increasing with the value of the external forces, and a second force proportional to said output pressure, said control means being sensitive to said output pressure, said movable member being urgable, in addition, by a spring acting in the same sense as said first and second forces.
Claim 3
Dependent Claim
117 words
Hydrostatic transmission according to claim 1, wherein the movable member of the pressure reducer is constituted by a slide valve capable of sliding in a cylinder in which it limits, by one of its ends, a first fluidtight chamber of variable volume connected to the output of the pressure reducer so that said slide valve is thus subjected to said second force, the bottom of said first chamber being traversed by a rod which emerges in a second fluidtight chamber which is connected to that one of said pipes which joins the inlet of the receiver machine to the delivery of the generator machine so that said rod receives and transmits to the slide said first force.
Claim 4
Dependent Claim
44 words
Hydrostatic transmission according to claim 2, wherein the second chamber receives a sliding piston which separates therein two compartments in which open respectively a connection with said pipe and outlet towards a pressure limiter valve, a passage of narrow section communicating said two compartments.
Claim 5
Dependent Claim
17 words
Hydrostatic transmission according to claim 3, wherein the passage of restricted section passes through the piston itself.
Claim 6
Dependent Claim
66 words
Hydrostatic transmission according to claim 2, wherein the force increasing with the speed of the generator machine acting on the slide of the pressure reducer is created by a pump driven mechanically by the generator machine or its motor and discharging in parallel to a calibrated leakage orifice and to a third fluidtight chamber limited inside the said cylinder by the other end of the slide.
Claim 7
Dependent Claim
54 words
Hydrostatic transmission according to claim 2, wherein said force increasing with the speed of the generator machine and acting on the slide of the pressure reducer is created by a centrifugal regulator driven mechanically by the generator machine or its motor and adapted to act by thrust on this other end of the slide.
Claim 8
Dependent Claim
83 words
Hydrostatic transmission according to claim 2, wherein the force increasing with the speed of the generator machine and acting on the slide of the pressure reducer is created by the difference of pressures existing respectively upstream and downstream of a restricted orifice or choke provided on the delivery pipe of a pump driven by said motor, the downstream portion of said pipe being provided with a pressure limiter adapted to maintain, in said delivery pipe, a continuous circulation of the liquid under pressure.
Claim 9
Dependent Claim
100 words
Hydrostatic transmission according to claim 1, which comprises at least two generator machines driven by a single motor, each generator machine being associated in a closed circuit with a receiver machine and possessing its individual mechanism for the variation of its unit flow, wherein said rod possesses as many shoulders of identical sections as there are generator machines and said second chamber is subdivided into as many partial CHAMBERS with which said shoulders co-operate and which are connected respectively to those of said pipes which join the inputs of the receiver machines to the deliveries of the corresponding generator machines.
Claim 10
Dependent Claim
66 words
Hydrostatic transmission according to claim 3, wherein the force increasing with the speed of the generator machine acting on the slide of the pressure reducer is created by a pump driven mechanically by the generator machine or its motor and discharging in parallel to a calibrated leakage orifice and to a third fluidtight chamber limited inside the said cylinder by the other end of the slide.
Claim 11
Dependent Claim
66 words
Hydrostatic transmission according to claim 4, wherein the force increasing with the speed of the generator machine acting on the slide of the pressure reducer is created by a pump driven mechanically by the generator machine or its motor and discharging in parallel to a calibrated leakage orifice and to a third fluidtight chamber limited inside the said cylinder by the other end of the slide.
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) | 1975-06-27 | 1975-12-27 | 1976-06-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-27 | 1979-12-27 | 1980-06-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-27 | 1983-12-27 | 1984-06-27 | $7700.00 | Window Closed / Lapsed |