8-speed transmission
View Patent ↗The transmission has a plurality of members that can be utilized in powertrains to provide eight forward speed ratios and one reverse speed ratio. The transmission includes three planetary gear sets, five torque-transmitting devices, one fixed interconnection, three external gear sets and a final drive gear set. The powertrain includes an engine and torque converter that is continuously connected to one of the planetary gear members and an output member that is continuously connected with one of the external gear sets. The five torque-transmitting devices provide interconnections between various planetary and external gear members, and the transmission housing, and are operated in combinations of three to establish eight forward speed ratios and one reverse speed ratio.
1. A multi-speed transmission comprising:
an input member;
an output member;
first, second and third planetary gear sets each having first, second and third members, said gear sets being positioned along first and second axes;
an interconnecting member continuously connecting said first member of said first planetary gear set with said third member of said second planetary gear set;
three external gears sets positioned for transferring torque between said first and second axes, said three external gear sets each including first and second intermeshed external gears; and
five torque-transmitting devices for selectively interconnecting said members of said planetary gear sets or said first and second external gears of said three gear sets with each other, with a stationary member, or with other members of said planetary gear sets, said five torque-transmitting devices being engaged in combinations of three to establish at least eight forward speed ratios and at least one reverse speed ratio between said input member and said output member.
2. The transmission of claim 1 , wherein a first of said five torque-transmitting devices is operable for selectively connecting said first member of said second planetary gear set with said stationary member.
3. The transmission of claim 2 , wherein a second of said five torque-transmitting devices is operable for selectively connecting said second external gear of said first external gear set with said third member of said third planetary gear set.
4. The transmission of claim 3 , wherein a third of said five torque-transmitting devices is operable for selectively connecting said third member of said first planetary gear set with said second member of said second planetary gear set.
5. The transmission of claim 4 , wherein a fourth of said five torque-transmitting devices is operable for selectively connecting said second external gear of said second external gear set with said first member of said third planetary gear set.
6. The transmission of claim 5 , wherein a fifth of said five torque-transmitting devices is operable for selectively connecting said second external gear of said second external gear set with said second member of said third planetary gear set.
7. The transmission defined in claim 1 , wherein said second member of said first planetary gear set is continuously connected with said first external gear of said second external gear set; said first member of said second planetary gear set is continuously connected with said first external gear of said first external gear set; said first member of said third planetary gear set is continuously connected with said second external gear of said third external gear set; said second member of said second planetary gear set is continuously connected with said first external gear of said third external gear set; said second member of said third planetary gear set is continuously connected with an external drive gear of a final drive external gear set.
8. The transmission of claim 1 , wherein said first, second and third members of said first, second and third planetary gear sets comprise a sun gear member, a planet carrier assembly member and a ring gear member, respectively.
9. The transmission of claim 1 , wherein said input member is continuously connected with said third member of said first planetary gear set, and said output member is continuously connected with a second external gear of a final drive external gear set.
10. A multi-speed transmission comprising:
an input member;
an output member;
first, second and third planetary gear sets each having first, second and third members, said gear sets being positioned along first and second axes;
an interconnecting member continuously connecting said first member of said first planetary gear set with said third member of said second planetary gear set;
three external gears sets positioned for transferring torque between said first and second axes, said three external gear sets each including first and second intermeshed external gears;
a first torque-transmitting device selectively connecting said first member of said second planetary gear set with a stationary member;
a second torque-transmitting device selectively connecting said second external gear of said first external gear set with said third member of said third planetary gear set;
a third torque-transmitting device selectively connecting third member of said first planetary gear set with said second member of said second planetary gear set;
a fourth torque-transmitting device selectively connecting said second external gear of said second external gear set with said first member of said third planetary gear set;
a fifth torque-transmitting device selectively connecting said second external gear of said second external gear set with said second member of said third planetary gear set; and
said five torque-transmitting devices being engaged in combinations of three to establish at least eight forward speed ratios and at least one reverse speed ratio between said input member and said output member.
11. The transmission of claim 10 , wherein said first, second and third members of said first, second and third planetary gear sets comprise a sun gear member, a planet carrier assembly member and a ring gear member, respectively.
12. The transmission of claim 10 , wherein said second member of said first planetary gear set is continuously connected with said first external gear of said second external gear set; said first member of said second planetary gear set is continuously connected with said first external gear of said first external gear set; said first member of said third planetary gear set is continuously connected with said second external gear of said third external gear set; said second member of said second planetary gear set is continuously connected with said first external gear of said third external gear set; and said second member of said third planetary gear set is continuously connected with a drive gear of a final drive external gear set.
13. The transmission of claim 10 , wherein said input member is continuously connected with said third member of said first planetary gear set, and said output member is continuously connected with a second external gear of a final drive external gear set.
14. A multi-speed transmission comprising:
an input member;
an output member;
first, second and third planetary gear sets each having a sun gear member, a planet carrier assembly member and a ring gear member, said gear sets being positioned along first and second axes;
an interconnecting member continuously connecting said sun gear member of said first planetary gear set with said ring gear member of said second planetary gear set;
three external gears sets positioned for transferring torque between said first and second axes, said three external gear sets each including first and second intermeshed external gears;
a first torque-transmitting device selectively connecting said sun gear member of said second planetary gear set with a stationary member;
a second torque-transmitting device selectively connecting said second external gear of said first external gear set with said ring gear member of said third planetary gear set;
a third torque-transmitting device selectively connecting ring gear member of said first planetary gear set with said planet carrier assembly member of said second planetary gear set;
a fourth torque-transmitting device selectively connecting said second external gear of said second external gear set with said sun gear member of said third planetary gear set;
a fifth torque-transmitting device selectively connecting said second external gear of said second external gear set with said planet carrier assembly member of said third planetary gear set; and
said five torque-transmitting devices being engaged in combinations of three to establish at least eight forward speed ratios and at least one reverse speed ratio between said input member and said output member.