US3799308A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Transmission clutches with feedback controlled pressure modulator
Assignee: International Motors LLC
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Filing: 1972-10-20
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Granted: 1974-03-26
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Expires: 1992-10-20
Abstract
Abstract Hydraulic mechanism in a transmission for engaging a clutch for first, second, or third speed before a clutch for the F-R, or forward or reverse, direction. Flow of pressure fluid to each speed clutch and to each direction clutch is by way of a scheduling valve which is back-pressure-operated in controlled way for throttling the flow. Back pressure originates in a sensing line from the power unit of each speed and direction clutch, and the different lines are differently orificed. After the power unit for the clutch for first, second, or third speed and the power unit for the F-R clutches are pre-filled with fluid, pressure in the power units is then slowly raised linearly toward its maximum, the slowness of rate depending upon the smallness of the orifice in each sensing line affected. The speed clutches are constructed, proportioned in size, and arranged to have smaller energy absorbing capacity in their design and they operate so as to be fully hydraulically engaged at a slightly lower pressure than, and hence slightly before, the F-R clutches.
Inventors
- 👤 E Erisman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 09:51
CPC Classifications
F; F16; F16H; F16H61/00; F16H61/02; F16H61/0262; F16H61/0265; F16H61/0272; F16H61/0274; F16H2708/00; F16H2708/24; F16H61/04; F16H61/06; F16H61/065
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
265 words
In a control system for a reversible, power shift transmission having sets of direction and range clutches, and clutch cylinder means individual thereto and operable under a pressure rate-of-rise to clutch engaging pressure for changing speeds and direction of drive: a source (22) of clutch charging fluid, under pressure; clutch selector means (28) for operation of selected ones of the clutch cylinder means among said sets of clutch cylinder means, and having a line from the fluid source from which the fluid is supplied by the selector means to the cylinder means so selected; a charging valve (32) connected in said line and controlled by a charge-pressure-movable area for closure of, and by a spring for the opening of, the valve, said spring being relatively weak and singly able to overcome no more than a predetermined low filling pressure exerted on the pressure movable area, by only part way opening the valve for causing flow under restricted pressure; an accumulator (44) having communication to a spring-augmenting pressure-movable-area on the valve so as to open the valve toward full opening at full pressure, the accumulator due to its volume controlling the pressure rate-of-rise of fluid fed into said communication; feedback lines individual to the clutch cylinder means and responsive to the clutch cylinder pressure thereof; and means selectively interconnecting feedback lines of only the cylinder means selected and said communication so that the spring augmenting pressure area proportionally aids in biasing the valve toward full opening at full pressure, as pressure in the selected clutch means and associated feed back lines increases toward clutch engaging pressure.
Claim 2
Dependent Claim
265 words
In a control system for a reversible, power shift transmission having sets of direction and range clutches, and clutch cylinder means individual thereto and operable under a pressure rate-of-rise to clutch engaging pressure for changing speeds and direction of drive: a source (22) of clutch charging fluid, under pressure; clutch selector means (28) for operation of selected ones of the clutch cylinder means among said sets of clutch cylinder means, and having a line from the fluid source from which the fluid is supplied by the selector means to the cylinder means so selected; a charging valve (32) connected in said line and controlled by a charge-pressure-movable area for closure of, and by a spring for the opening of, the valve, said spring being relatively weak and singly able to overcome no more than a predetermined low filling pressure exerted on the pressure movable area, by only part way opening the valve for causing flow under restricted pressure; an accumulator (44) having communication to a spring-augmenting pressure-movable-area on the valve so as to open the valve toward full opening at full pressure, the accumulator due to its volume controlling the pressure rate-of-rise of fluid fed into said communication; feedback lines individual to the clutch cylinder means and responsive to the clutch cylinder pressure thereof; and means selectively interconnecting feedback lines of only the cylinder means selected and said communication so that the spring augmenting pressure area proportionally aids in biasing the valve toward full opening at full pressure, as pressure in the selected clutch means and associated feed back lines increases toward clutch engaging pressure.
Claim 3
Dependent Claim
190 words
In a control system for a reversible, power shift transmission having sets of direction and speed range clutches, and clutch cylinder means individual thereto and operable for causing said clutches to change speeds and direction of drive: a source of clutch charging fluid, under pressure of the order of clutch engaging pressure; clutch selector means for operation of selected ones of the clutch cylinder means among said sets of clutch cylinder means; an intercommunication which is operatively disposed between the fluid source and clutch selector means and which is controllable to operatively open and supply clutch cylinder fluid through the clutch selector means; a fluid accumulator which, when cyclically replenished with another fluid charge during a change in transmission setting, accumulates back pressure proportionally; feedback means individual to the clutch cylinder means and responsive to the clutch cylinder pressure thereof; means selectively connecting feedback means of only the cylinder means selected and said accumulator and transmitting a pressure rate-of-rise into the accumulator; and control means in the intercommunication responsive to pressure rate-of-rise in said accumulator for progressively opening the intercommunication ultimately to supply the pressure fluid at substantially undiminished pressure.
Claim 4
Dependent Claim
190 words
In a control system for a reversible, power shift transmission having sets of direction and speed range clutches, and clutch cylinder means individual thereto and operable for causing said clutches to change speeds and direction of drive: a source of clutch charging fluid, under pressure of the order of clutch engaging pressure; clutch selector means for operation of selected ones of the clutch cylinder means among said sets of clutch cylinder means; an intercommunication which is operatively disposed between the fluid source and clutch selector means and which is controllable to operatively open and supply clutch cylinder fluid through the clutch selector means; a fluid accumulator which, when cyclically replenished with another fluid charge during a change in transmission setting, accumulates back pressure proportionally; feedback means individual to the clutch cylinder means and responsive to the clutch cylinder pressure thereof; means selectively connecting feedback means of only the cylinder means selected and said accumulator and transmitting a pressure rate-of-rise into the accumulator; and control means in the intercommunication responsive to pressure rate-of-rise in said accumulator for progressively opening the intercommunication ultimately to supply the pressure fluid at substantially undiminished pressure.
Claim 5
Dependent Claim
50 words
The invention of claim 2 and: means providing restrictions in the feedback means, a plurality of which feedback means differ from the others in magnitude of their restriction-to-flow to the accumulator, to more greatly slow the accumulator pressure rate-of-rise and, perforce, the pressure rate-of-rise in the clutch cylinder means selected.
Claim 6
Dependent Claim
73 words
The invention of claim 3, in combination with the clutch cylinder means of which a forward one is for a forward clutch in the set of direction clutches and a first one is for a first speed clutch in the set of range clutches; a restriction of smallness affording the greatest magnitude of restriction-to-flow being in the feedback means from at least one of the just said ones of the clutch cylinder means.
Claim 7
Dependent Claim
197 words
The invention of claim 4: the feedback selective-connecting means comprising a shuttle valve common to the respective feedback means from said forward clutch cylinder and from a reverse clutch cylinder for a reverse clutch in the set of direction clutches, and automatically opening under feedback pressure in the feedback means from the selected one of the forward and reverse clutch cylinders to intercommunicate such feedback means and the accumulator and cause a pressure rate-of-rise; a second shuttle valve common to the respective feedback means from a second clutch cylinder for a second speed clutch in the set of range clutches and from a third clutch cylinder for a third speed clutch in the set of range clutches, and automatically opening an outlet under feedback pressure in the feedback means from the selected one of the second and third clutch cylinders; and a third shuttle valve common to the respective feedback means from said first clutch cylinder and from said second shuttle valve outlet, and automatically opening under feedback pressure in the feedback means from the clutch cylinder selected among first, second, and third clutch cylinders, to intercommunicate such feedback means and accumulator and cause a pressure rate-of-rise.
Claim 8
Dependent Claim
39 words
The invention of claim 5: said restriction providing means comprising orifice-type check valves affording restricted flow in a first direction charging fluid into the accumulator and affording relatively unrestricted flow in the opposite direction for cyclically emptying the accumulator.
Claim 9
Dependent Claim
33 words
The invention of claim 6, wherein restrictions are provided in a plurality but not all of the feedback means, whereby certain of the accumulator''s charging-and-emptying flow is utilized relatively unrestricted in both directions.
Claim 10
Dependent Claim
101 words
The invention of claim 3, characterized by: each clutch cylinder means in the respective sets of clutch cylinder means comprising an opposing spring means and a companion cylinder, each such spring means and companion cylinder being constructed, proportioned, and arranged relatively to one another and to the clutch concerned to insure that the clutch cylinder means for the set of speed clutches achieve clutch engaging pressure at a pressure lower than for the set of direction clutches and, perforce, the selected ones of the clutch cylinder means operate for engaging a speed clutch before a clutch for forward or reverse direction.
Claim 11
Dependent Claim
43 words
The invention of claim 8, in combination with: the sets of forward and reverse direction and speed range clutches; the speed clutches being constructed, proportioned in size, and arranged with smaller energy absorbing capacity than either the forward or the reverse direction clutch.
Claim 12
Dependent Claim
184 words
In a method of scheduling clutch pressures through signal pressure application in the operation of a power shift transmission having a final line pressure source for providing actuating pressure, sets of direction and speed clutch mechanisms, clutch selector means for said mechanisms, a line pressure intercommunication operatively disposed between the final line pressure source and clutch selector means and controllable to operatively open and supply the mechanisms selected with actuating pressure through the clutch selector means, and accumulator means in which to accumulate the scheduling pressure, the steps comprising: development of a reduced first signal as a function of the selected speed clutch pressure; development of a reduced second signal as a function of the selected direction clutch pressure; application of the first and second signals as a combined back pressure signal to the accumulator so that the latter accumulates accumulator scheduling pressure substantially linearly and proportionately to the first and second signals jointly; and regulation of the opening of the line pressure intercommunication so as to control the pressure therein as a function of the substantially linear rate of riSe of scheduling pressure.
Claim 13
Dependent Claim
184 words
In a method of scheduling clutch pressures through signal pressure application in the operation of a power shift transmission having a final line pressure source for providing actuating pressure, sets of direction and speed clutch mechanisms, clutch selector means for said mechanisms, a line pressure intercommunication operatively disposed between the final line pressure source and clutch selector means and controllable to operatively open and supply the mechanisms selected with actuating pressure through the clutch selector means, and accumulator means in which to accumulate the scheduling pressure, the steps comprising: development of a reduced first signal as a function of the selected speed clutch pressure; development of a reduced second signal as a function of the selected direction clutch pressure; application of the first and second signals as a combined back pressure signal to the accumulator so that the latter accumulates accumulator scheduling pressure substantially linearly and proportionately to the first and second signals jointly; and regulation of the opening of the line pressure intercommunication so as to control the pressure therein as a function of the substantially linear rate of riSe of scheduling pressure.
Claim 14
Dependent Claim
40 words
In the invention of claim 10, the further steps comprising: engagement of the selected speed clutch mechanism at less than final pressure; and engagement of the selected direction clutch mechanism upon attainment of final pressure in said line pressure intercommunication.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-03-25 | 1977-09-24 | 1978-03-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-03-25 | 1981-09-24 | 1982-03-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-03-25 | 1985-09-24 | 1986-03-26 | $7700.00 | Window Closed / Lapsed |