Eight speed automatic transmission

• US 8,231,498 B2
• Filed: 06/15/2011
• Issued: 07/31/2012
• Est. Priority Date: 04/02/2007
• Status: Expired due to Fees

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: Carey, Clinton E., Hart, James M., Phillips, Andrew W., Wittkopp, Scott H.
• Primary Examiner(s): Le, David D
• Assistant Examiner(s): Bishop, Erin D
• Application Number:
  US13/161,221
• Publication Number:
  US 20110245021A1
• Time in Patent Office: 412 Days
• Field of Search: 475/282
• US Class Current: 475/282
• CPC Class Codes: F16H 2200/006 the gear ratios comprising eight forward speeds
• CPC Class Codes: F16H 2200/2012 with four sets of orbital gears
• CPC Class Codes: F16H 2200/2043 with five engaging means
• CPC Class Codes: F16H 3/666 with compound planetary gear units, e.g. two intermeshing orbital gears F16H3/663 takes precedence

Abstract

An eight speed automatic transmission is provided having an input member, an output member, four planetary gear sets and five torque transmitting devices. Three of the planetary gear sets are simple and one planetary gear set is compound. Each of the plurality of planetary gear sets has first, second and third members: a sun gear, a ring gear and a planet carrier having a plurality of planet gears rotatably disposed thereon. Three of the torque transmitting devices are clutches and two of the devices are brakes. Eight embodiments of the transmission having different arrangements of the planetary gear sets, clutches and brakes are disclosed.

Claims

1. An automatic transmission comprising:

an input member;

an output member;

a transmission housing having a first wall, a second wall and a third wall extending between said first and said second walls;

a first, a second, a third and a fourth planetary gear assembly disposed within said transmission housing, wherein said second planetary gear assembly is adjacent said first wall, said first planetary gear assembly is adjacent said second planetary gear assembly, said fourth planetary gear assembly is adjacent said first planetary gear assembly and said third planetary gear assembly is between said fourth planetary gear assembly and said second wall, each of said planetary gear assemblies including a sun gear member, a ring gear member and a planet carrier member supporting a plurality of planet gears meshing with said sun gear member and said ring gear member,

wherein said input member is coupled to said planet carrier of said first planetary gear assembly, said output member is coupled to said planet carrier of said third planetary gear assembly, said ring gear member of said third planetary gear assembly is coupled to said planet carrier of said fourth planetary gear assembly, said sun gear member of said first planetary gear assembly is coupled to said sun gear member of said fourth planetary gear assembly, said sun gear member of said second planetary gear assembly is coupled to said sun gear member of said third planetary gear assembly and said ring gear member of said first planetary gear assembly is coupled to said planet carrier of said second planetary gear assembly, and wherein said first, said third and said fourth planetary gear assemblies are simple and said second planetary gear assembly is compound,

wherein said transmission housing has a first area radially inward from an outer periphery of said planetary gear assemblies and axially bounded by said first wall and said second planetary gear assembly, a second area radially inward from said outer periphery of said planetary gear assemblies and axially bounded by said second and said first planetary gear assemblies, a third area radially inward from said outer periphery of said planetary gear assemblies and axially bounded by said first and said fourth planetary gear assemblies, a fourth area radially inward from said outer periphery of said planetary gear assemblies and axially bounded by said fourth and said third planetary gear assemblies, a fifth area radially inward from said outer periphery of said planetary gear assemblies and axially bounded by said third planetary gear assembly and said second wall, and a sixth area between said outer periphery of said planetary gear assemblies and said third wall and axially bounded by said first wall and said second wall;

a first clutch selectively engageable between said planet carrier of said first planetary gear assembly and said sun gear member of said second planetary gear assembly;

a second clutch selectively engageable between said sun gear member of said second planetary gear assembly and said planet carrier of said second planetary gear assembly;

a third clutch selectively engageable between said ring gear member of said second planetary gear assembly and said ring gear member of said third planetary gear assembly;

a first brake selectively engageable between said sun gear member of said fourth planetary gear assembly and said transmission housing;

a second brake selectively engageable between said ring gear member of said fourth planetary gear assembly and said transmission housing,

wherein said first clutch is located in one of said first, second and sixth areas, said second clutch is located in one of said first, second and sixth areas, said third clutch is located in one of said second, fourth and sixth areas, said first brake is located in one of said first, fifth and sixth areas and said second brake is located in one of said first, fifth and sixth areas, and

wherein said clutches and brakes are selectively engageable to establish at least eight forward speed ratios and one reverse speed ratio between said input member and said output member.

2. The automatic transmission of claim 1 wherein at least one of said first clutch, said second clutch, said first brake and said second brake is located in said first area.

3. The automatic transmission of claim 1 wherein at least one of said first clutch, said second clutch and said third clutch is located in said second area.

4. The automatic transmission of claim 1 wherein said third clutch is located in said fourth area.

5. The automatic transmission of claim 1 wherein at least one of said first brake and said second brake is located in said fifth area.

6. The automatic transmission of claim 1 wherein at least one of said first clutch, said second clutch, said third clutch, said first brake and said second brake is located in said sixth area.

7. The automatic transmission of claim 1 wherein said first brake is located in said sixth area.

8. The automatic transmission of claim 1 wherein said second brake is located in said first area.

9. The automatic transmission of claim 1 wherein said second brake is located in said fifth area.

10. The automatic transmission of claim 1 wherein said second brake is located in said sixth area.

11. The automatic transmission of claim 1 wherein said first clutch is located in said first area.

12. The automatic transmission of claim 1 wherein said first clutch is located in said second area.

13. The automatic transmission of claim 1 wherein said first clutch is located in said sixth area.

14. The automatic transmission of claim 1 wherein said second clutch is located in said first area.

15. The automatic transmission of claim 1 wherein said second clutch is located in said second area.

16. The automatic transmission of claim 1 wherein said second clutch is located in said sixth area.

17. The automatic transmission of claim 1 wherein said third clutch is located in said second area.

18. The automatic transmission of claim 1 wherein said third clutch is located in said sixth area.

19. An automatic transmission comprising:

an input member;

an output member;

a transmission housing having a first wall, a second wall and a third wall extending between said first and said second walls;

a first, a second, a third and a fourth planetary gear assembly disposed within said transmission housing, wherein said second planetary gear assembly is adjacent said first wall, said first planetary gear assembly is adjacent said second planetary gear assembly, said fourth planetary gear assembly is adjacent said first planetary gear assembly and said third planetary gear assembly is between said fourth planetary gear assembly and said second wall, each of said planetary gear assemblies including a sun gear member, a ring gear member and a planet carrier member supporting a plurality of planet gears meshing with said sun gear member and said ring gear member,

wherein said input member is coupled to said planet carrier of said first planetary gear assembly, said output member is coupled to said planet carrier of said third planetary gear assembly, said ring gear member of said third planetary gear assembly is coupled to said planet carrier of said fourth planetary gear assembly, said sun gear member of said first planetary gear assembly is coupled to said sun gear member of said fourth planetary gear assembly, said sun gear member of said second planetary gear assembly is coupled to said sun gear member of said third planetary gear assembly and said ring gear member of said first planetary gear assembly is coupled to said planet carrier of said second planetary gear assembly, and wherein said first, said third and said fourth planetary gear assemblies are simple and said second planetary gear assembly is compound,

wherein said transmission housing has a first area radially inward from an outer periphery of said planetary gear assemblies and axially bounded by said first wall and said second planetary gear assembly, a second area radially inward from said outer periphery of said planetary gear assemblies and axially bounded by said second and said first planetary gear assemblies, a third area radially inward from said outer periphery of said planetary gear assemblies and axially bounded by said first and said fourth planetary gear assemblies, a fourth area radially inward from said outer periphery of said planetary gear assemblies and axially bounded by said fourth and said third planetary gear assemblies, a fifth area radially inward from said outer periphery of said planetary gear assemblies and axially bounded by said third planetary gear assembly and said second wall, and a sixth area between said outer periphery of said planetary gear assemblies and said third wall and axially bounded by said first wall and said second wall;

a first clutch selectively engageable between said planet carrier of said first planetary gear assembly and said sun gear member of said second planetary gear assembly;

a second clutch selectively engageable between said sun gear member of said second planetary gear assembly and said planet carrier of said second planetary gear assembly;

a third clutch selectively engageable between said ring gear member of said second planetary gear assembly and said ring gear member of said third planetary gear assembly;

a first brake selectively engageable between said sun gear member of said fourth planetary gear assembly and said transmission housing;

a second brake selectively engageable between said ring gear member of said fourth planetary gear assembly and said transmission housing,

wherein said first clutch is located in said first area, said second clutch is located in said first area, said third clutch is at least partially located in at least one of said second and sixth areas, said first brake is located in said sixth area, and said second brake is located in said sixth area, and

wherein said clutches and brakes are selectively engageable to establish at least eight forward speed ratios and one reverse speed ratio between said input member and said output member.