Patent US4668958A successfully refreshed from Google Patents.
Patent US4718306A successfully refreshed from Google Patents.
US4718306A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Power transmission for use in automobiles continuously variable transmission
Assignee: Toyota Motor Corp
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Filing: 1987-04-07
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Granted: 1988-01-12
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Expires: 2007-04-07
Abstract
Abstract A belt type continuously valiable transmission (CVT) comprises a pair of input pulleys, a pair of output pulleys and a belt trained over input and output pulleys to transmit power. Each pair of the pulleys has a hydraulic cylinder for pressing the pulleys against the belt. A line pressure used in one cylinder is controlled by adjusting an electric pressure regulating valve. A correction value is calculated which corresponds to the square of the rotational speed of the hydraulic cylinder to which line pressure is supplied. The value of control signal of the pressure regulating valve is corrected in accordance with the correction value, so that the error of the line pressure due to a centrifugal force is compensated for.
Inventors
- 👤 Takashi Shigematsu
- 👤 Tomoyuki Watanabe
- 👤 Setsuo Tokoro
- 👤 Daisaku Sawada
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 11:10
CPC Classifications
B; B60; B60W; B60W10/00; B60W10/10; B60W10/101; B60W10/107; B60W10/04; B60W30/00; B60W30/18; B60W30/1819; B60W30/188; B60W30/1882; F; F16; F16H; F16H61/00; F16H61/66; F16H61/662; F16H61/66254; F16H61/66259
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
179 words
A method for compensating the line pressure in a continuously variable transmission, of a vehicle wherein said transmission has a pair of input pulleys controlled by a hydraulic pressure which is supplied to pulleys in a rotably mounted hydraulic cylinder and a pair of output pulleys, controlled in the same manner as said input pulleys, with a belt trained over said pulleys to transmit torque between said input pulleys and said output pulleys comprising the steps of: determining the input torque Tin transmitted to said input pulley pair; determining the rotational speed Nin of said input pulley pairs; determining the output speed Nout of said output pulley pair; determining a basic control value for the line pressure in response to said input torque Tin and an output/input speed ratio e of said output speed Nout and said input speed Nin; compensating said basic control value by as a function of the square of said output rotational speed Nout to compensate for errors produced by the centrifugal force; controlling the line pressure in response to said compensated basic control value.
Claim 2
Independent Claim
179 words
A method for compensating the line pressure in a continuously variable transmission, of a vehicle wherein said transmission has a pair of input pulleys controlled by a hydraulic pressure which is supplied to pulleys in a rotably mounted hydraulic cylinder and a pair of output pulleys, controlled in the same manner as said input pulleys, with a belt trained over said pulleys to transmit torque between said input pulleys and said output pulleys comprising the steps of: determining the input torque Tin transmitted to said input pulley pair; determining the rotational speed Nin of said input pulley pairs; determining the output speed Nout of said output pulley pair; determining a basic control value for the line pressure in response to said input torque Tin and an output/input speed ratio e of said output speed Nout and said input speed Nin; compensating said basic control value by as a function of the square of said output rotational speed Nout to compensate for errors produced by the centrifugal force; controlling the line pressure in response to said compensated basic control value.
Claim 3
Dependent Claim
16 words
A method as in claim 1 where said input torque is determined by a torque sensor.
Claim 4
Dependent Claim
45 words
A method as defined in claim 1, wherein said input torque Tin is determined by the following formula: Tin=Te+ΔTe+K6(dNe/dt)+K7(dNin/dt) provided Te is an engine torque, ΔTe is an increment of engine torque corresponding to air-fuel ratio reduction of mixture and K6 and K7 are constants.
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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) | 1991-01-11 | 1991-07-13 | 1992-01-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-01-11 | 1995-07-13 | 1996-01-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-01-11 | 1999-07-13 | 2000-01-12 | $7700.00 | Window Closed / Lapsed |