Planetary gear transmission systems or components – Input from independent power sources – Including electric motor input
Reexamination Certificate
2000-02-04
2001-05-22
Marmor, Charles A (Department: 3681)
Planetary gear transmission systems or components
Input from independent power sources
Including electric motor input
C475S002000, C477S004000, C477S005000
Reexamination Certificate
active
06234930
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a transmission comprising motors and differential mechanisms, as well as a vehicle using the same.
BACKGROUND ART
As a drive system capable of reducing the fuel consumption of an engine there is known a hybrid vehicle which utilizes a motor drive force.
Various types of hybrid vehicles such as series type and parallel type have been proposed, among which is included a series-parallel hybrid type using two motors and one planetary gear. For example, in Japanese Patent Laid-open No. Hei 7-135701 there is disclosed a method wherein a driving force of an engine is inputted to a planetary gear and control is made by a generator so that a vehicle is driven with a driving force obtained from an output shaft of the planetary gear. While a part of energy of the engine is generated by a generator, a driving force is assisted from a motor connected to the output shaft to drive the engine always in a high torque region of a high efficiency, and at the same time a speed change function can be attained.
The same principle as above is also described in Japanese Patent Laid-open Nos. Sho 49-112067 and Sho 58-191364.
According to the methods disclosed therein, power is generated by a generator and a driving force is obtained by a motor for realizing a speed change function, so that there occurs an electrical energy loss. Consequently, there occurs reduction in efficiency by an amount corresponding to the electrical energy loss with respect to the whole of the vehicle concerned despite the engine can be driven always at a highly efficient operating point.
The present invention has been accomplished in view of the above-mentioned problems and it is the first object of the invention to provide a small-sized transmission constituted by small-sized motors, thereby realizing a stepless speed change function which permits vehicular operation in a region of a high engine efficiency while minimizing an electrical energy loss.
It is the second object of the present invention to provide a vehicle capable of being driven in a region of a high engine efficiency while minimizing an electrical energy loss.
DISCLOSURE OF THE INVENTION
The above first object of the present invention is achieved by a transmission having a plurality of differential mechanisms in which motors control a difference in the number of revolutions between an input shaft and an output shaft thereof, the input and output shafts for the plural differential mechanisms being used in common, wherein gear ratios from the input shafts to the output shafts in the plural differential mechanisms are set at a value different to each other, and gear ratios from the input shafts to the motors in the plural differential mechanisms are set at a value different to each other.
Particularly, this construction is effective in reducing the size of the motor which controls the differential mechanism smaller in the gear ratio from the input shafts to the output shafts.
The above first object is achieved also by a transmission having a plurality of differential mechanisms in which motor shafts driven by motors control a difference in the number of revolutions between an input shaft and an output shaft thereof, the input and output shafts for the plural differential mechanisms being used in common, wherein gear ratios from the input shafts to the output shafts in the plural differential mechanisms are set at a value different to each other, the transmission further having a locking/unlocking mechanism for locking and unlocking the motor shaft in at least the differential mechanism larger in the gear ratio of the plural differential mechanisms.
According to this construction it is possible to reduce the size of the motor disposed on the side where the locking/unlocking mechanism is provided. Thus, by using both means described above in combination it is made possible to provide a transmission still smaller in size.
The above second object of the present invention is achieved by a vehicle having an engine which generates a driving energy for driving the vehicle and a transmission which changes the rotational speed of the engine and transmits a driving force to wheels, the transmission having at least first and second differential mechanisms which input the driving force from the engine and output a driving force for the wheels, and also having first and second motors for controlling the first and second differential mechanisms, respectively, wherein gear ratios from input shafts to output shafts in the first and second differential mechanisms are set at a value different to each other and gear ratios from the input shafts to the first and second motors are set at a value different to each other.
The above second object of the present invention is achieved also by a vehicle having an engine which generates a driving energy for driving the vehicle and a transmission which changes the rotational speed of the engine and transmits a driving force to wheels, the transmission having at least first and second differential mechanisms which input the driving force from the engine and output a driving force for the wheels, and also having first and second motors for controlling the first and second differential mechanisms, respectively, wherein a gear ratio from an input shaft to an output shaft in the first differential mechanism is set at a value larger than a gear ratio from an input shaft to an output shaft in the second differential mechanism, the transmission further having a locking/unlocking mechanism for locking and unlocking a motor shaft which transmits the driving force of at least the first motor to the first differential mechanism.
REFERENCES:
patent: 3757912 (1973-09-01), Ball et al.
patent: 5211610 (1993-05-01), Hurth
patent: 5558589 (1996-09-01), Schmidt
patent: 5558595 (1996-09-01), Schmidt et al.
patent: 5904631 (1999-05-01), Morisawa et al.
patent: 5931757 (1999-08-01), Schmidt
patent: 5947855 (1999-09-01), Weiss
patent: 6053833 (2000-04-01), Masaki
patent: 0047054 (1982-03-01), None
Kaneko Satoru
Masaki Ryoso
Matsunobu Yutaka
Evenson, McKeown, Edwards & Lenahan P.L.L.C.
Hitachi , Ltd.
Ho Ha
Marmor Charles A
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