Planetary gear transmission systems or components – With means to vary drive ratio or disconnect drive – Plural elements selectively braked
Reexamination Certificate
1999-12-15
2001-10-16
Marmor, Charles A (Department: 3681)
Planetary gear transmission systems or components
With means to vary drive ratio or disconnect drive
Plural elements selectively braked
C475S296000
Reexamination Certificate
active
06302821
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a power train of automatic transmission, and more particularly to a power train of automatic transmission adapted to initiate a shift stage of five forward speeds and one reverse speed with two planetary gear sets and seven friction elements for compactness, lightness and decreased power loss at three forward speeds.
2. Description of the Prior Art
Generally, an automatic transmission is mounted with a transmission control unit for automatically controlling a transmission ratio according to running speed of a vehicle and load change. The transmission control unit controls a plurality of friction elements mounted at a power train in operation or inoperation state to adjust revolution at an output terminal by selecting any one of three elements at the planetary gear sets (sun gear, ring gear and planetary carrier) as an input element and the others as reaction force element.
Actually, in order to design a power train for outputting a transmission ratio on four forward speeds and one reverse speed, a combined planetary gear set combining two simple planetary gear sets and at least five friction elements should be used.
Furthermore, the combined planetary gear set has planetary carriers directly connected for at least two different elements to be commonly used, or for a sun gear to be commonly used, or for planetary carrier and ring gear to be directly connected, or for the planetary carrier and the ring gear to be directly and commonly connected in direct structure, possessing four dependent actuating elements.
However, there is a problem in the power train thus described in that its engine performance cannot be fully utilized in a recent trend of high powered engine although a shift stage of four forward speeds and one reverse speed can be obtained. In other words, the automatic transmission cannot achieve good fuel consumption rate, power and driving performances. Lately, as a means for fully utilizing an engine performance at a high-powered engine, a power train having a shift stage of five forward speeds and one speed has been disclosed for multi-staging the transmission ratio. A power train according to the prior art proposed for a shift stage of five forward speeds and one reverse speed needs three simple planetary gear sets and six friction elements, or a power train that requires three simple planetary gear sets and seven friction elements has been provided.
SUMMARY OF THE INVENTION
However, there is a problem in the power train for providing a shift stage of five forward speeds and one reverse speed according to the prior art thus described in that the power train needs three simple planetary gear set and six friction elements, or three simple planetary gear sets and seven friction elements, thereby complication its structure and making it difficult to control.
Furthermore, there is another problem in that manufacturing cost thereof is increased to put a heavy financial burden to a vehicle purchaser and decrease sales competitive ness.
The present invention is disclosed to solve the aforementioned problems and it is an object of the present invention to provide a power train of automatic transmission adapted to initiate a shift stage of five forward speeds and one reverse speed with two simple planetary gear sets and seven friction elements. There is another object of the present invention to provide a power train of automatic transmission adapted to realize compactness and lightness and to decrease a power loss at three forward speeds.
In accordance with the objects of the present invention, there is provided a power train of automatic transmission, the power training comprising:
a combined planetary gear set provided by fixedly connecting a planetary carrier of a first signal pinion planetary gear set to a ring gear of a second single pinion planetary gear set, and by fixedly connecting a ring gear of a first single pinion planetary gear set to a planetary carrier of a second single pinion planetary gear set;
three input means for causing an input to be variably initiated to any of three actuating elements out of various actuating elements at the combined planetary gear set;
two output means for causing an output to be variably initiated from any of two actuating elements out of various actuating elements at the first single pinion planetary gear set; and
two brakes actuating as reaction force.
According to the preferable embodiment, the input means comprises:
a first clutch for being mounted between a sun gear of first single pinion planetary gear set and an input axle to variably connect same;
a second clutch for being mounted between a planetary carrier of second single pinion planetary gear set and an input axle to variably connect same; and
a third clutch for being mounted between a sun gear of second single pinion planetary gear set and an input axle to variably connect same.
Also, the output means comprises:
a fourth clutch for being mounted between a planetary carrier of first single pinion planetary gear set and a transfer drive gear to variably connect same; and
a fifth clutch for being mounted between a sun gear of first single pinion planetary gear set and a transfer drive gear to variably connect same.
The brake comprises:
a first brake for selecting a ring gear as reaction force element between the ring gear of first single pinion planetary gear set and a transmission housing; and
a second brake for selecting a sun gear as reaction force element between the sun gear of second single pinion planetary gear set and a transmission housing.
REFERENCES:
patent: 4602525 (1986-07-01), Moroto et al.
patent: 4955851 (1990-09-01), Arzoian et al.
patent: 5605517 (1997-02-01), Sherman
patent: 5707312 (1998-01-01), Sefcik
patent: 5816972 (1998-10-01), Park
patent: 5833568 (1998-11-01), Park
patent: 5853345 (1998-12-01), Park
patent: 5868645 (1999-02-01), Beim et al.
patent: 5876300 (1999-03-01), Moroto et al.
patent: 6110069 (2000-08-01), Taniguchi et al.
patent: 0371651 (1990-06-01), None
patent: 2-129447 (1990-05-01), None
Birch & Stewart Kolasch & Birch, LLP
Hyundai Motor Company
Marmor Charles A
Pang Roger
LandOfFree
Power train of automatic transmission does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Power train of automatic transmission, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Power train of automatic transmission will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2599249