Seven-speed transmission

• US 20050079945A1
• Filed: 10/08/2003
• Published: 04/14/2005
• Est. Priority Date: 10/08/2003
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations Incorporated (Motors Liquidation Co. GUC Trust)
• Inventors: Wittkopp, Scott H.
• Granted Patent: US 6,910,986 B2
• Time in Patent Office: Days
• US Class Current: 475/271
• CPC Class Codes: F16H 2200/0056 the gear ratios comprising seven forward speeds
• CPC Class Codes: F16H 2200/201 with three sets of orbital gears
• CPC Class Codes: F16H 3/66 composed of a number of gear trains without drive passing from one train to another

Abstract

A seven-speed transmission includes an input shaft, an output shaft, and a planetary gear arrangement having three planetary gear sets. The input shaft and output shaft are continuously connected with specific members of the gear sets. Three interconnecting members continuously connect specific members of the gear sets. Three brakes and three clutches are engageable in combinations of two to establish seven forward speed ratios and a reverse speed ratio between the input shaft and the output shaft.

Claims

1. A seven-speed transmission comprising:

an input shaft;

an output shaft;

a planetary gear arrangement having first, second and third planetary gear sets, each planetary gear set having a ring gear member, sun gear member and planet carrier assembly member;

said input shaft being continuously interconnected with said sun gear member of the second planetary gear set, said output shaft being continuously interconnected with said planet carrier assembly member of the third planetary gear set;

a first interconnecting member continuously connecting said ring gear member of said first planetary gear set with said planet carrier assembly member of said third planetary gear set;

a second interconnecting member continuously connecting said planet carrier assembly member of said first planetary gear set with said ring gear member of said second planetary gear set;

a third interconnecting member continuously connecting said planet carrier assembly member of said second planetary gear set with said ring gear member of said third planetary gear set;

a first brake selectively interconnecting a transmission housing with said planet carrier assembly member of the first planetary gear set;

a second brake selectively interconnecting said transmission housing with said sun gear member of the first planetary gear set;

a third brake selectively interconnecting said transmission housing with said sun gear member of the third planetary gear set;

a first clutch selectively interconnecting said sun gear member of the first planetary gear set with said sun gear member of the second planetary gear set;

a second clutch selectively interconnecting said planet carrier assembly member of the first planetary gear set with said sun gear member of the second planetary gear set;

a third clutch selectively interconnecting said sun gear member of the second planetary gear set with said sun gear member of the third planetary gear set; and

said first, second and third brakes, and first, second and third clutches being engaged in combinations of two to establish seven forward speed ratios and a reverse speed ratio between said input shaft and said output shaft.

2. The seven-speed transmission of claim 1, wherein said first, second and third planetary gear sets are simple planetary gear sets.

3. The seven-speed transmission of claim 1, wherein said third clutch is positioned radially inward from said third brake.

4. The seven-speed transmission of claim 1, wherein ratio steps for sequential shift changes between first and seventh speeds are each between approximately 1.1 and 1.7.

5. The seven-speed transmission of claim 1, wherein a seventh of said seven forward speed ratios is an overdrive ratio.

6. A seven-speed transmission comprising:

an input shaft;

an output shaft;

a planetary gear arrangement having first, second and third planetary gear sets, each planetary gear set having a ring gear member, sun gear member and planet carrier assembly member;

said input shaft being continuously interconnected with said sun gear member of the second planetary gear set, said output shaft being continuously interconnected with said planet carrier assembly member of the third planetary gear set;

a first interconnecting member continuously connecting said ring gear member of said first planetary gear set with said planet carrier assembly member of said third planetary gear set;

a second interconnecting member continuously connecting said planet carrier assembly member of said first planetary gear set with said ring gear member of said second planetary gear set;

a third interconnecting member continuously connecting said planet carrier assembly member of said second planetary gear set with said ring gear member of said third planetary gear set;

a first brake selectively interconnecting a transmission housing with said planet carrier assembly member of the first planetary gear set;

a second brake selectively interconnecting said transmission housing with said sun gear member of the first planetary gear set;

a third brake selectively interconnecting said transmission housing with said sun gear member of the third planetary gear set;

a first clutch selectively interconnecting said sun gear member of the first planetary gear set with said sun gear member of the second planetary gear set;

a second clutch selectively interconnecting said planet carrier assembly member of the first planetary gear set with said sun gear member of the second planetary gear set;

a third clutch selectively interconnecting said sun gear member of the second planetary gear set with said sun gear member of the third planetary gear set;

said first, second and third brakes, and first, second and third clutches being engaged in combinations of two to establish seven forward speed ratios and a reverse speed ratio between said input shaft and said output shaft;

wherein said third clutch is positioned radially inward from said third brake; and

wherein ratio steps for sequential shift changes between first and seventh speeds are each between approximately 1.1 and 1.7.