Eight speed automatic transmission

• US 8,435,152 B2
• Filed: 04/16/2012
• Issued: 05/07/2013
• 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:
  US13/447,934
• Publication Number:
  US 20120202637A1
• Time in Patent Office: 386 Days
• Field of Search: None
• US Class Current: 475/275
• 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;

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 third planetary gear assembly is adjacent said second planetary gear assembly, said first planetary gear assembly is adjacent said third planetary gear assembly and said fourth planetary gear assembly is between said first 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;

an input member coupled to said planet carrier of said first planetary gear assembly, wherein said input member is partially disposed radially outward of said first, second, and third planetary gear assemblies;

an output member coupled to said planet carrier of said third planetary gear assembly, wherein said output member is partially disposed radially inward of said first and fourth planetary gear assemblies;

a first interconnecting member continuously directly coupling said ring gear member of said third planetary gear assembly with said planet carrier of said fourth planetary gear assembly, wherein said first interconnecting member is partially disposed between said first and said third planetary gear assemblies radially outward of said output member, and partially disposed radially inward of said first and fourth planetary gear assemblies radially outward of said output member;

a second interconnecting member continuously directly coupling said sun gear member of said first planetary gear assembly with said sun gear member of said fourth planetary gear assembly, wherein said second interconnecting member is partially disposed between said first and fourth planetary gear assemblies radially outward of said first interconnecting member;

a third interconnecting member continuously directly coupling said sun gear member of said second planetary gear assembly with said sun gear member of said third planetary gear assembly, wherein said third interconnecting member is partially disposed between said second and third planetary gear assemblies;

a fourth interconnecting member continuously directly coupling said ring gear member of said first planetary gear assembly with said planet carrier of said second planetary gear assembly, wherein said fourth interconnecting member is partially disposed radially inward of said input member and radially outward of said second planetary gear assembly, said third planetary gear assembly, and said first interconnecting member;

first, second, and third clutches each selectively engageable to interconnect at least one of said members of at least one of said planetary gear assemblies with at least one other of said members of at least one of said planetary gear assemblies; and

first and second brakes each selectively engageable to interconnect said transmission housing with at least one of said members of at least one of said planetary gear assemblies, 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 said first clutch is selectively engageable to interconnect said planet carrier of said first planetary gear assembly with said sun gear member of said second planetary gear assembly, and wherein said first clutch is disposed radially inward of said input member.

3. The automatic transmission of claim 1 wherein said second clutch is selectively engageable to interconnect said sun gear member of said second planetary gear assembly with said planet carrier of said second planetary gear assembly, and wherein said second clutch is disposed radially inward of said input member.

4. The automatic transmission of claim 1 wherein said third clutch is selectively engageable to interconnect said ring gear member of said second planetary gear assembly with said ring gear member of said third planetary gear assembly, wherein said third clutch is disposed radially inward of said fourth interconnecting member.

5. The automatic transmission of claim 1 wherein said first brake is selectively engageable to interconnect said sun gear member of said fourth planetary gear assembly with said transmission housing.

6. The automatic transmission of claim 5 wherein said first brake is disposed radially outward of said output member.

7. The automatic transmission of claim 1 wherein said second brake is selectively engageable to interconnect said ring gear member of said fourth planetary gear assembly with said transmission housing.

8. The automatic transmission of claim 7 wherein said second brake is disposed radially outward of said output member.

9. The automatic transmission of claim 8 wherein said second brake is disposed radially inward of said first brake.

10. The automatic transmission of claim 1 wherein said first, said third and said fourth planetary gear assemblies are simple and said second planetary gear assembly is compound.

11. An automatic transmission comprising;

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 third planetary gear assembly is adjacent said second planetary gear assembly, said first planetary gear assembly is adjacent said third planetary gear assembly and said fourth planetary gear assembly is between said first 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,

an input member coupled to said planet carrier of said first planetary gear assembly, wherein said input member is partially disposed radially outward of said first, second, and third planetary gear assemblies;

an output member coupled to said planet carrier of said third planetary gear assembly, wherein said output member is partially disposed radially inward of said first and fourth planetary gear assemblies;

a first interconnecting member continuously directly coupling said ring gear member of said third planetary gear assembly with said planet carrier of said fourth planetary gear assembly, wherein said first interconnecting member is partially disposed between said first and said third planetary gear assemblies radially outward of said output member, and partially disposed radially inward of said first and fourth planetary gear assemblies radially outward of said output member;

a second interconnecting member continuously directly coupling said sun gear member of said first planetary gear assembly with said sun gear member of said fourth planetary gear assembly, wherein said second interconnecting member is partially disposed between said first and fourth planetary gear assemblies radially outward of said first interconnecting member;

a third interconnecting member continuously directly coupling said sun gear member of said second planetary gear assembly with said sun gear member of said third planetary gear assembly, wherein said third interconnecting member is partially disposed between said second and third planetary gear assemblies;

a fourth interconnecting member continuously directly coupling said ring gear member of said first planetary gear assembly with said planet carrier of said second planetary gear assembly, wherein said fourth interconnecting member is partially disposed radially inward of said input member and radially outward of said second planetary gear assembly, said third planetary gear assembly, and said first interconnecting member;

a first clutch selectively engageable to interconnect said planet carrier of said first planetary gear assembly with said sun gear member of said second planetary gear assembly;

a second clutch selectively engageable to interconnect said sun gear member of said second planetary gear assembly with said planet carrier of said second planetary gear assembly;

a third clutch selectively engageable to interconnect said ring gear member of said second planetary gear assembly with said ring gear member of said third planetary gear assembly;

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

a second brake selectively engageable to interconnect said ring gear member of said fourth planetary gear assembly with said transmission housing, 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.

12. The automatic transmission of claim 11 wherein said first clutch is disposed radially inward of said input member.

13. The automatic transmission of claim 11 wherein said second clutch is disposed radially inward of said input member.

14. The automatic transmission of claim 11 wherein said third clutch is disposed radially inward of said fourth interconnecting member.

15. The automatic transmission of claim 11 wherein said first brake is disposed radially outward of said output member.

16. The automatic transmission of claim 11 wherein said second brake is disposed radially outward of said output member.

17. The automatic transmission of claim 16 wherein said second brake is disposed radially inward of said first brake.

18. The automatic transmission of claim 11 wherein said first, said third and said fourth planetary gear assemblies are simple and said second planetary gear assembly is compound.

19. An automatic transmission comprising;

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 third planetary gear assembly is adjacent said second planetary gear assembly, said first planetary gear assembly is adjacent said third planetary gear assembly and said fourth planetary gear assembly is between said first 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 first, said third and said fourth planetary gear assemblies are simple and said second planetary gear assembly is compound;

an input member coupled to said planet carrier of said first planetary gear assembly, wherein said input member is partially disposed radially outward of said first, second, and third planetary gear assemblies;

an output member coupled to said planet carrier of said third planetary gear assembly, wherein said output member is partially disposed radially inward of said first and fourth planetary gear assemblies;

a first interconnecting member continuously directly coupling said ring gear member of said third planetary gear assembly with said planet carrier of said fourth planetary gear assembly, wherein said first interconnecting member is partially disposed between said first and said third planetary gear assemblies radially outward of said output member, and partially disposed radially inward of said first and fourth planetary gear assemblies radially outward of said output member;

a second interconnecting member continuously directly coupling said sun gear member of said first planetary gear assembly with said sun gear member of said fourth planetary gear assembly, wherein said second interconnecting member is partially disposed between said first and fourth planetary gear assemblies radially outward of said first interconnecting member;

a third interconnecting member continuously directly coupling said sun gear member of said second planetary gear assembly with said sun gear member of said third planetary gear assembly, wherein said third interconnecting member is partially disposed between said second and third planetary gear assemblies;

a fourth interconnecting member continuously directly coupling said ring gear member of said first planetary gear assembly with said planet carrier of said second planetary gear assembly, wherein said fourth interconnecting member is partially disposed radially inward of said input member and radially outward of said second planetary gear assembly, said third gear assembly, and said first interconnecting member;

a first clutch selectively engageable to interconnect said planet carrier of said first planetary gear assembly with said sun gear member of said second planetary gear assembly, wherein said first clutch is disposed radially inward of said input member;

a second clutch selectively engageable to interconnect said sun gear member of said second planetary gear assembly with said planet carrier of said second planetary gear assembly, wherein said second clutch is disposed radially inward of said input member;

a third clutch is selectively engageable to interconnect said ring gear member of said second planetary gear assembly with said ring gear member of said third planetary gear assembly, wherein said third clutch is disposed radially inward of said fourth interconnecting member;

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

a second brake selectively engageable to interconnect said ring gear member of said fourth planetary gear assembly with said transmission housing, 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.

20. The automatic transmission of claim 19 wherein said first brake is disposed radially outward of said output member, and said second brake is disposed radially outward of said output member and radially inward of said first brake.