×

Eight speed automatic transmission

  • US 8,251,858 B2
  • Filed: 06/15/2011
  • Issued: 08/28/2012
  • Est. Priority Date: 04/02/2007
  • Status: Expired due to Fees
First Claim
Patent Images

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 fourth planetary gear assembly is adjacent said first wall, said first planetary gear assembly is adjacent said fourth planetary gear assembly, said second planetary gear assembly is adjacent said first planetary gear assembly and said third planetary gear assembly is between said second 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 continuously directly coupled to said sun gear member of said fourth planetary gear assembly, said sun gear member of said second planetary gear assembly is continuously directly 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,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 fourth planetary gear assembly, a second area radially inward from said outer periphery of said planetary gear assemblies and axially bounded by said fourth 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 second planetary gear assemblies, a fourth area radially inward from said outer periphery of said planetary gear assemblies and axially bounded by said second 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; and

    a second brake selectively engageable between said ring gear member of said fourth planetary gear assembly and said transmission housing, andwherein said first clutch is located in one of said first, second, third, fourth and fifth areas, said second clutch is located in one of said third, fourth and sixth areas, said third clutch is located in one of said third, fourth, fifth and sixth areas, said first brake is located in one of said first, second, fifth and sixth areas and said second brake is located in one of said first, second, fifth and sixth areas, andwherein 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.

View all claims
  • 2 Assignments
Timeline View
Assignment View
    ×
    ×