Planetary gear transmission systems or components – With means to vary drive ratio or disconnect drive – Plural elements selectively braked
Patent
1991-09-06
1993-07-06
Lorence, Richard M.
Planetary gear transmission systems or components
With means to vary drive ratio or disconnect drive
Plural elements selectively braked
475282, F16H 5710
Patent
active
052249085
DESCRIPTION:
BRIEF SUMMARY
TECHNOLOGICAL FIELD
The present invention relates to an automatic transmission for an automobile.
TECHNOLOGICAL BACKGROUND
In the prior art, the automatic transmission for automobile is composed of a plurality of planetary gear units, and frictional engagement components such as brakes or clutches connected to the individual components of said planetary gear units so that it can realize individual gear stages by having the individual frictional engagement components selectively engaged. Generally speaking, a simpson type automatic transmission establishes three forward speeds and is equipped with two single planetary gear units, in which these single planetary gear units have their sun gears shared, and in which the carrier of the first planetary gear unit and the ring gear of the second planetary gear unit are integrally connected.
In order to establish a fourth speed, moreover, an overdrive mechanism or under drive mechanism composed of a single planetary gear unit is added to the three-speed automatic transmission mechanism which acts as a base composed of the aforementioned two planetary gear units.
In recent years, the need for shortening the axial size of the automatic transmission has become more acute because of the FF trend (i.e., front engine and front drive) in automobiles.
To meet this need, there has been provided a structure in which the aforementioned three-spaced automatic transmission mechanism and the overdrive mechanism or underdrive mechanism are arranged on two parallel axes (as disclosed in Japanese Patent Laid-Open No. 62-141343 or corresponding U.S. Pat. No. 4,716,787).
In the automatic transmission having the structure thus far described, however, the three-speed automatic transmission mechanism and the overdrive or underdrive mechanism are arranged on the two axes so that the overall axial length can be reduced. However, the weight of the automatic transmission is increased because planetary gear unit is required for forming the overdrive or underdrive mechanism.
DISCLOSURE OF THE INVENTION
An object of the present invention is to solve the aforementioned problems of the automatic transmissions of the prior art and to provide a forward four-speed automatic transmission which is freed from any increase in the axial size and in the weight. In order to achieve the above-specified object, according to the present invention, there is provided an automatic transmission which comprises: a single planetary gear unit 10; a dual planetary gear 11 disposed adjacent to said single planetary gear unit 10 and having a sun gear formed integrally therewith and a carrier connected integrally thereto; an input shaft 15 extending from the output member of a torque converter 50; a clutch C1 for engaging or releasing said input shaft 15 and the ring gear R1 of said single planetary gear 10 through a connecting member 16; and a clutch C2 for engaging or releasing said input shaft 15 and said sun gear, wherein said connecting member 16 is connected to the ring gear R2 of the dual planetary gear 11 through a clutch C0, wherein there are provided a brake B1 for engaging or releasing said sun gear and a brake B2 for engaging or releasing the ring gear of said dual planetary gear 11, and wherein an output gear 13 is connected to said carrier.
There may be a further provided a clutch C3 and a one-way clutch F0 for engaging or releasing said connecting member 16 and the ring gear R1 of said single planetary gear 10, and a one-way clutch F1 for engaging or releasing the ring gear R2 of said dual planetary gear 11.
Moreover, the clutch C3 for engaging or releasing said connecting member 16 and the ring gear R1 of said single planetary gear 10 may be arranged adjacent to the ring gear R2 of said single planetary gear 10.
Brake B1 for engaging or releasing the sun gear and the clutch C2 for engaging or releasing the input shaft 15 and the sun gears are disposed adjacent to each other, and the aforementioned output gear 13 may be arranged between the brake and clutch and the planetary gear.
According to the
REFERENCES:
patent: 4716787 (1988-01-01), Miura et al.
patent: 4916977 (1990-04-01), Aoki et al.
patent: 4934215 (1990-06-01), Miura et al.
patent: 4994007 (1991-02-01), Miura et al.
patent: 5006102 (1991-04-01), Takase et al.
Hayakawa Yoichi
Hosono Chihiro
Nishida Masaaki
Aisin Aw Co. Ltd.
Levi Benjamin
Lorence Richard M.
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