Multi-speed transmission
View Patent ↗An automatic transmission is provided having an input member, an output member, four planetary gear sets, a plurality of coupling members and a plurality of torque transmitting devices. Each of the planetary gear sets includes first, second and third members. The torque transmitting devices may be either brakes or clutches. Eight forward speeds or gear ratios and reverse are achieved by engaging various combinations of the brakes and clutches.
1. A transmission comprising:
an input member;
an output member;
first, second, third and fourth planetary gear sets each having first, second and third members;
a first interconnecting member continuously interconnecting the second member of the first planetary gear set with the first member of the second planetary gear set;
a second interconnecting member continuously interconnecting the third member of the first planetary gear set with the second member of the second planetary gear set;
a third interconnecting member continuously interconnecting the second member of the second planetary gear set with the third member of the third planetary gear set;
a fourth interconnecting member continuously interconnecting the third member of the second planetary gear set with the second member of the fourth planetary gear set;
a fifth interconnecting member continuously interconnecting the first member of the third planetary gear set with the first member of the fourth planetary gear set; and
five torque transmitting mechanisms each selectively engageable to interconnect one of the first, second, and third members with another of a stationary element, the first members, the second members, and the third members of the first, second, third, and fourth planetary gear sets, wherein a first of the five torque transmitting mechanisms is selectively engageable to interconnect the first member of the first planetary gear set with the stationary element; and
wherein the input member is continuously interconnected with at least one of the first members, the second members, and the third members of the first, second, third, and fourth planetary gear sets, and
wherein the torque transmitting mechanisms are selectively engageable in combinations of at least two to establish at least eight forward speed ratios and at least one reverse speed ratio between the input member and the output member.
2. The transmission of claim 1 wherein a second of the five torque transmitting mechanisms is selectively engageable to interconnect the first member of the third planetary gear set with the stationary element.
3. The transmission of claim 2 wherein a third of the five torque transmitting mechanisms is selectively engageable to interconnect the third member of the fourth planetary gear set with the stationary element.
4. The transmission of claim 3 wherein a fourth of the five torque transmitting mechanisms is selectively engageable to interconnect the third member of the first planetary gear set with the third member of the fourth planetary gear set.
5. The transmission of claim 4 wherein a fifth of the five torque transmitting mechanisms is selectively engageable to interconnect the third member of the second planetary gear set with the second member of the third planetary gear set.
6. The transmission of claim 1 wherein the first members of the first, second, third, and fourth planetary gear sets are sun gears, the second members of the first, second, third, and fourth planetary gear sets are carrier members, and the third members of the first, second, third, and fourth planetary gear sets are ring gears.
7. The transmission of claim 1 wherein the input member is continuously interconnected with the second member of the first planetary gear set and with the first member of the second planetary gear set and wherein the output member is continuously interconnected with the second member of the third planetary gear set.
8. The transmission of claim 1 wherein the torque transmitting mechanisms include two clutches and three brakes.
9. A transmission comprising:
an input member;
an output member;
first, second, third and fourth planetary gear sets each having first, second and third members, wherein the input member is continuously interconnected with the second member of the first planetary gear set and with the first member of the second planetary gear set and wherein the output member is continuously interconnected with the second member of the third planetary gear set;
a first interconnecting member continuously interconnecting the second member of the first planetary gear set with the first member of the second planetary gear set;
a second interconnecting member continuously interconnecting the third member of the first planetary gear set with the second member of the second planetary gear set;
a third interconnecting member continuously interconnecting the second member of the second planetary gear set with the third member of the third planetary gear set;
a fourth interconnecting member continuously interconnecting the third member of the second planetary gear set with the second member of the fourth planetary gear set;
a fifth interconnecting member continuously interconnecting the first member of the third planetary gear set with the first member of the fourth planetary gear set;
a first torque transmitting mechanism selectively engageable to interconnect the first member of the first planetary gear set with the stationary element;
a second torque transmitting mechanism selectively engageable to interconnect the first member of the third planetary gear set with the stationary element;
a third torque transmitting mechanism selectively engageable to interconnect the third member of the fourth planetary gear set with the stationary element;
a fourth torque transmitting mechanism selectively engageable to interconnect the third member of the first planetary gear set with the third member of the fourth planetary gear set; and
a fifth torque transmitting mechanism selectively engageable to interconnect the second member of the third planetary gear set with the third member of the second planetary gear set; and
wherein the torque transmitting mechanisms are selectively engageable in combinations of at least two to establish at least eight forward speed ratios and at least one reverse speed ratio between the input member and the output member.
10. The transmission of claim 9 wherein the first members of the first, second, third, and fourth planetary gear sets are sun gears, the second members of the first, second, third, and fourth planetary gear sets are carrier members, and the third members of the first, second, third, and fourth planetary gear sets are ring gears.
11. A transmission comprising:
an input member;
an output member;
first, second, third and fourth planetary gear sets each having a sun gear, a carrier member, and a ring gear, wherein the input member is continuously interconnected with the carrier member of the first planetary gear set and with the sun gear of the second planetary gear set and wherein the output member is continuously interconnected with the carrier member of the third planetary gear set;
a first interconnecting member continuously interconnecting the carrier member of the first planetary gear set with the sun gear of the second planetary gear set;
a second interconnecting member continuously interconnecting the ring gear of the first planetary gear set with the carrier member of the second planetary gear set;
a third interconnecting member continuously interconnecting the carrier member of the second planetary gear set with the ring gear of the third planetary gear set;
a fourth interconnecting member continuously interconnecting the ring gear of the second planetary gear set with the carrier member of the fourth planetary gear set;
a fifth interconnecting member continuously interconnecting the sun gear of the third planetary gear set with the sun gear of the fourth planetary gear set;
a first torque transmitting mechanism selectively engageable to interconnect the sun gear of the first planetary gear set with the stationary element;
a second torque transmitting mechanism selectively engageable to interconnect the sun gear of the third planetary gear set with the stationary element;
a third torque transmitting mechanism selectively engageable to interconnect the ring gear of the fourth planetary gear set with the stationary element;
a fourth torque transmitting mechanism selectively engageable to interconnect the ring gear of the first planetary gear set with the ring gear of the fourth planetary gear set; and
a fifth torque transmitting mechanism selectively engageable to interconnect the carrier member of the third planetary gear set with the ring gear of the second planetary gear set; and
wherein the torque-transmitting mechanisms are selectively engageable in combinations of at least two to establish at least eight forward speed ratios and at least one reverse speed ratio between the input member and the output member.