Powertrain with a multi-speed transmission

Details Powertrain with a multi-speed transmission Powertrain with a multi-speed transmission

1999-11-22

2001-02-27

Estremsky, Sherry (Department: 3681)

Planetary gear transmission systems or components

With means to vary drive ratio or disconnect drive

Plural elements selectively braked

C475S325000

Reexamination Certificate

active

06193626

ABSTRACT:

TECHNICAL FIELD
This invention relates to powertrains having multi-speed power transmissions and more particularly to power transmissions having at least five forward speeds.
BACKGROUND OF THE INVENTION
In an effort to improve the overall performance of a vehicle while also reducing the mass of the vehicle, the number of speed ratios available through the transmission is increased. This permits a more efficient use of the engine operating range while also reducing the size of the engine. The increased number of speed ratios allows for a higher low gear ratio which will result in a reduced size torque converter.
The number of forward speed ratios in power transmissions has increased from two to five over a number of years. Many of the five speed transmissions incorporate two or three interconnected simple or compound planetary gear sets and five or six selectively engageable clutches or brakes. These transmissions quite often include one or more bridging clutches when two interconnected planetary gear sets are utilized. One example of this type of power transmission can be seen in U.S. Pat. No. 5,830,102 issued to Coffey on Nov. 3, 1998.
Currently, many manufacturers are considering increasing the number of ratios to six or seven. These transmissions generally contain three planetary gear sets. One such transmission is seen in U.S. Pat. No. 3,946,623 issued Mar. 30, 1976. This prior art transmission incorporates four interconnected planetary gear sets, three clutches and four brakes when more than five speed ratios are to be attained.
A six speed planetary transmission having two simple planetary gear sets is disclosed in U.S. Pat. No. 09/383,429 filed Aug. 27, 1999 and assigned to the assignee of this application. Other six speed planetary transmissions having a simple planetary gear set and a compound planetary gear set are disclosed in co-pending U.S. Ser. Nos. 09/442,310 filed Nov. 22, 1999, Ser. No. 09/442.309 filed Nov. 22, 1999, and Ser. No. 09/442,307 filed Nov. 22, 1999.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an improved powertrain with a planetary transmission having six forward speeds.
In one aspect of the present invention, a planetary gear arrangement has a simple planetary gear set and a compound gear set that are interconnected. In another aspect of the present invention, the ring gear member of the simple planetary gear set is continually drivingly connected with the transmission output shaft. In yet another aspect of the present invention, the sun gear member and the ring gear member of the compound planetary gear set are individually selectively connectable with the input shaft by way of selectively operable torque transmitting mechanisms.
In still another aspect of the present invention, using two interconnecting selectively operable torque transmitting mechanisms, the ring gear member and the carrier assembly member of the simple planetary gear set are selectively connectable with the ring gear member of the compound planetary gear set. In a further aspect of the present invention, two additional torque transmitting mechanisms cooperate with the abovementioned four torque transmitting mechanisms to establish six forward speed ratios and one reverse speed ratio when the torque transmitting mechanisms are engaged in combinations of three.


REFERENCES:
patent: 2873625 (1959-02-01), Simpson
patent: 3946623 (1976-03-01), Murakami et al.
patent: 5141477 (1992-08-01), Oshidari
patent: 5393279 (1995-02-01), Bota et al.
patent: 5567201 (1996-10-01), Ross
patent: 5830102 (1998-11-01), Coffey

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