Planetary gear transmission systems or components – Input from independent power sources – Plural outputs
Patent
1999-05-18
2000-12-26
Estremsky, Sherry
Planetary gear transmission systems or components
Input from independent power sources
Plural outputs
475 9, 475221, 475903, 74665M, F16H 372, F16H 3708
Patent
active
061650943
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
This invention relates to vehicle powertrains.
BACKGROUND ART
Vehicle powertrains generally comprise power unit and power transmission subsystems. Vehicular power transmission subsystems conventionally include a main transmission and an automotive differential gear assembly for differentially driving two drive wheels.
In order to couple power unit efficiency with the variable speed and power demands of a vehicle, a requirement exists for a vehicle powertrain wherein the power unit and the power transmission can be continuously controlled as an integrated unit over the full range of operation so that the performance characteristics of the powertrain can be adaptively and synergistically optimised in response to command inputs from the vehicle driver. A preferred components of such an adaptively controlled vehicle powertrain is a transmission capable of transmitting power at a continuously variable output speed. Such transmissions may be generically described as continuously variable transmissions.
Previously proposed continuously variable transmissions have tended to be complex, unreliable and inefficient at high torque loads. For these and other practical size, weight and cost considerations, previously proposed continuously variable transmissions have typically been ill-suited for use in vehicle powertrains. A requirement accordingly exists for an efficient, compact and reliable continuously variable transmission that is suitable for use is vehicle powertrains.
DISCLOSURE OF THE INVENTION
According to a first aspect of the present invention, there is provided a power transmission unit including an outer main transmission and an inner differential gear assembly, the main transmission having two rotatable input means operably connected to rotatable output means so that the rotational speed of the output means can vary in proportion to the algebraic mean of the speeds of rotation of two input means, the differential gear assembly being arranged internally of the main transmission and having rotatable input means operably connected to two differentially rotatable output means, wherein the output means of the main transmission and the input means of the differential gear assembly are operably connected.
According to a second aspect of the present invention, there is provided a vehicle powertrain capable of being continuously controlled over a predetermined range of operation including: differential gear assembly; connected to a power unit for receiving rotational power, the two input means being operably connected to rotatable output means so that the rotational speed of the output means can vary in proportion to the algebraic mean of the speeds of rotation of two input means; transmission and having rotatable input means operably connected to two differentially rotatable output means, wherein the output means of the main transmission and the input means of the differential gear assembly are operably connected; determining performance parameters associated with the operation of the powertrain, wherein the performance parameters include the load on each of the two power units, the rotational speeds of each of the two input means of the main transmission, the load on each of the two output means of the differential gear assembly, and the rotational speeds of each of the two output means of the differential gear assembly; continuously monitor, analyse and adjust the performance parameters in response to command input.
The two power units advantageously comprise any similar or dissimilar combination of any of the range of conventional internal combustion engine types--including the Otto engine, the Diesel engine, the rotary engine or the gas turbine engine--or conventional electric motor types. The Otto and Diesel internal combustion engines are preferred because they represent established technologies with relatively low production costs. Advantageously, the two power units are arranged such that their rotational power output means, such as crankshafts in the case of internal combust
REFERENCES:
patent: 1720018 (1929-07-01), Tubbs
patent: 2196368 (1940-04-01), Thomson
patent: 2366646 (1945-01-01), Orr
patent: 5902206 (1999-05-01), Oda et al.
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