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, six torque-transmitting devices, two fixed interconnections and a grounded member. The powertrain includes an engine and torque converter that is selectively connected to one of the planetary gear members and an output member that is continuously connected with another one of the planetary gear members. The six torque-transmitting devices provide interconnections between various gear members, the input member 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;
a first interconnecting member continuously connecting said second member of said first planetary gear set with said second member of said third planetary gear set;
a second interconnecting member continuously connecting said third member of said first planetary gear set with said second member of said second planetary gear set;
said first member of said first planetary gear set being continuously connected with a stationary member;
six torque-transmitting devices each for selectively interconnecting a respective one of said members of said planetary gear sets with said input member, with said stationary member or with another respective one of said members of said planetary gear sets for rotation at a respective common speed, said six 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; wherein one of said six torque-transmitting mechanisms is selectively engagable to directly connect said third member of said second planetary gear set with said first member of said second planetary gear set for rotation at the same speed;
wherein another of said six torque-transmitting devices is selectively engagable to directly connect said second member of said first planetary gear set with said input member for rotation at a speed of the input member;
wherein a first of said six torque-transmitting devices is operable for selectively connecting said second member of said first planetary gear set with said stationary member;
wherein a second of said six torque-transmitting devices is operable for selectively connecting said third member of said second planetary gear set with said third member of said third planetary gear set;
wherein said one of said torque-transmitting devices is said third of said six torque-transmitting devices;
wherein a fourth of said six torque-transmitting devices is operable for selectively connecting said first member of said second planetary gear set with said input member; and
wherein a fifth of said six torque-transmitting devices is operable for selectively connecting said first member of said third planetary gear set with said third member of said second planetary gear set, said fifth of said six torque-transmitting devices being engaged in at least two of said at least eight forward speed ratios.
2. The transmission of claim 1 , wherein said another of said six torque-transmitting devices is a sixth of said six torque-transmitting devices.
3. The transmission defined in claim 1 , wherein said first torque-transmitting device comprises a brake, and said second, third, fourth, fifth and sixth torque-transmitting devices comprise clutches.
4. 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.
5. The transmission of claim 1 , wherein said output member is continuously connected with said third member of said third planetary gear set.
6. 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 output member being continuously connected with said third member of said third planetary gear set;
a first interconnecting member continuously connecting said second member of said first planetary gear set with said second member of said third planetary gear set;
a second interconnecting member continuously connecting said third member of said first planetary gear set with said second member of said second planetary gear set;
said first member of said first planetary gear set being continuously connected with a stationary member;
a first torque-transmitting device selectively connecting said second member of said first planetary gear set with said stationary member;
a second torque-transmitting device selectively connecting said third member of said second planetary gear set with said third member of said third planetary gear set for common rotation at one speed;
a third torque-transmitting device selectively directly connecting said third member of said second planetary gear set with said first member of said second planetary gear set for rotation at the same speed;
a fourth torque-transmitting device selectively connecting said first member of said second planetary gear set with said input member;
a fifth torque-transmitting device selectively connecting said first member of said third planetary gear set with said third member of said second planetary gear set;
a sixth torque-transmitting device selectively connecting said second member of said first planetary gear set with said input member for common rotation at a speed of the input member; and
said six 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.
7. The transmission of claim 6 , 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.
8. A multi-speed transmission comprising:
an input member;
an output member;
first, second and third planetary gear sets each having a sun gear member, planet carrier assembly member and ring gear member;
said output member being continuously interconnected with said ring gear member of said third planetary gear set;
said sun gear member of said first planetary gear set being continuously connected with a stationary member;
a first interconnecting member continuously connecting said planet carrier assembly member of said first planetary gear set with said planet carrier assembly member of said third planetary gear set;
a second interconnecting member continuously connecting said ring gear member of said first planetary gear set with said planet carrier assembly member of said second planetary gear set;
a first torque-transmitting device selectively connecting said planet carrier assembly member of said first planetary gear set with said stationary member;
a second torque-transmitting device selectively connecting said ring gear member of said second planetary gear set with said ring gear member of said third planetary gear set;
a third torque-transmitting device selectively directly connecting said ring gear member of said second planetary gear set with said sun gear member of said second planetary gear set for rotation at the same speed;
a fourth torque-transmitting device selectively connecting said sun gear member of said second planetary gear set with said input member;
a fifth torque-transmitting device selectively connecting said sun gear member of said third planetary gear set with said ring gear member of said second planetary gear set;
a sixth torque-transmitting device selectively connecting said planet carrier assembly member of said first planetary gear set with said input member;
said six torque-transmitting devices being engaged in combinations of three to establish eight forward speed ratios and one reverse speed ratio between said input member and said output member.