Single overdrive six-speed transmission with low internal speeds
View Patent ↗A six-speed transmission includes an input shaft, an output shaft, and a planetary gear arrangement having first, second and third planetary gear sets, each planetary gear set having first, second and third members. First and second interconnecting members continuously interconnect members of the planetary gear sets. The six torque-transmitting mechanisms are engaged in combinations of two to establish six forward speed ratios and at least one reverse speed ratio between the input shaft and the output shaft. The second and third sun gears hold the reaction torque in the first through fourth speeds, resulting in low planetary gear loading, which provides small gear sets, reduced clutch loading, reduced internal speeds, and low losses.
1. A multi-speed transmission comprising:
an input shaft;
an output shaft;
a planetary gear arrangement having first, second and third planetary gear sets, each planetary gear set having first, second and third members;
said input shaft being continuously interconnected with said first member of said first planetary gear set, and said output shaft being continuously interconnected with said second member of said second planetary gear set;
a first interconnecting member continuously interconnecting said first member of said second planetary gear set with said second member of said third planetary gear set;
a second interconnecting member continuously interconnecting said third member of said second planetary gear set with said third member of said third planetary gear set;
said third member of said first planetary gear set being continuously connected with a stationary member;
a first torque-transmitting mechanism selectively interconnecting said first member of said first planetary gear set with said first member of said third planetary gear set;
a second torque-transmitting mechanism selectively interconnecting said first member of said first planetary gear set with said first member of said second planetary gear set;
a third torque-transmitting mechanism selectively interconnecting said second member of said first planetary gear set with said second member of said third planetary gear set;
a fourth torque-transmitting mechanism selectively interconnecting said second member of said first planetary gear set with said first member of said third planetary gear set;
a fifth torque-transmitting mechanism selectively interconnecting said second member of said third planetary gear set with said stationary member; and
a sixth torque-transmitting mechanism selectively interconnecting said third member of said third planetary gear set with said stationary member;
wherein said six torque-transmitting mechanisms are engaged in combinations of two to provide at least one reverse speed ratio and six forward speed ratios.
2. The transmission of claim 1 , wherein a first forward speed ratio is established with the engagement of said fourth and sixth torque-transmitting mechanisms; a second forward speed ratio is established with the engagement of said third and sixth torque-transmitting mechanisms; a third forward speed ratio is established with the engagement of said first and sixth torque-transmitting mechanisms; a fourth forward speed ratio is established with the engagement of said second and sixth torque-transmitting mechanisms; a fifth forward speed ratio is established with the engagement of said second and first torque-transmitting mechanisms; a sixth forward speed ratio is established with the engagement of said second and fourth torque-transmitting mechanisms; and a reverse speed ratio is established with the engagement of said fourth and fifth torque-transmitting mechanisms.
3. The transmission of claim 1 , wherein said first, second and third planetary gear sets are simple planetary gear sets.
4. The transmission of claim 1 , wherein said first planetary gear set is a compound planetary gear set, and said second and third planetary gear sets are simple planetary gear sets.
5. The transmission of claim 1 , wherein each of said first members is a ring gear, each of said second members is a planet carrier assembly member, and each of said third members is a sun gear.
6. The transmission of claim 1 , wherein said first, second and third members of said first planetary gear set comprise a sun gear, a planet carrier assembly member and a ring gear, respectively, and said first, second and third members of said second and third planetary gear sets comprise a ring gear, a planet carrier assembly member, and a sun gear, respectively.
7. The transmission of claim 1 , wherein said first, second and third members of said first planetary gear set comprise a planet carrier assembly member, a ring gear, and a sun gear, respectively, and said first, second and third members of said second and third planetary gear sets comprise a ring gear, a planet carrier assembly member, and a sun gear, respectively.
8. The transmission of claim 1 , wherein said first, second, third and fourth torque-transmitting mechanisms comprise rotating clutches, and said fifth and sixth torque-transmitting mechanisms comprise brakes.
9. The transmission of claim 1 , wherein said fifth forward speed ratio is a 1:1 ratio.
10. The transmission of claim 5 , wherein said ring gear of said first planetary gear set has 85 teeth; said sun gear of said first planetary gear set has 55 teeth; said ring gear of said second planetary gear set has 81 teeth; said sun gear of said second planetary gear set has 21 teeth; said ring gear of said third planetary gear set has 81 teeth; and said sun gear of said third planetary gear set has 29 teeth.
11. The transmission of claim 6 , wherein said ring gear of said first planetary gear set has 85 teeth; said sun gear of said first planetary gear set has 55 teeth; said ring gear of said second planetary gear set has 81 teeth; said sun gear of said second planetary gear set has 31 teeth; said ring gear of said third planetary gear set has 81 teeth; and said sun gear of said third planetary gear set has 49 teeth.
12. The transmission of claim 7 , wherein said ring gear of said first planetary gear set has 81 teeth; said sun gear of said first planetary gear set has 41 teeth; said ring gear of said second planetary gear set has 81 teeth; said sun gear of said second planetary gear set has 23 teeth; said ring gear of said third planetary gear set has 81 teeth; and said sun gear of said third planetary gear set has 35 teeth.
13. The transmission of claim 1 , wherein a sun gear of said second and third planetary gear sets are grounded in the first, second, third and fourth forward speed ratios.
14. The transmission of claim 1 , wherein the transmission is shifted between the first and reverse speed ratios by engaging and disengaging brakes.
15. A multi-speed transmission comprising:
an input shaft;
an output shaft;
a planetary gear arrangement having first, second and third planetary gear sets, each planetary gear set having first, second and third members;
said input shaft being continuously interconnected with said first member of said first planetary gear set, and said output shaft being continuously interconnected with said second member of said second planetary gear set;
a first interconnecting member continuously interconnecting said first member of said second planetary gear set with said second member of said third planetary gear set;
a second interconnecting member continuously interconnecting said third member of said second planetary gear set with said third member of said third planetary gear set;
said third member of said first planetary gear set being continuously connected with a stationary member;
a first torque-transmitting mechanism selectively interconnecting said first member of said first planetary gear set with said first member of said third planetary gear set;
a second torque-transmitting mechanism selectively interconnecting said first member of said first planetary gear set with said first member of said second planetary gear set;
a third torque-transmitting mechanism selectively interconnecting said second member of said first planetary gear set with said second member of said third planetary gear set;
a fourth torque-transmitting mechanism selectively interconnecting said second member of said first planetary gear set with said first member of said third planetary gear set;
a fifth torque-transmitting mechanism selectively interconnecting said second member of said third planetary gear set with said stationary member; and
a sixth torque-transmitting mechanism selectively interconnecting said third member of said third planetary gear set with said stationary member;
wherein a first forward speed ratio is established with the engagement of said fourth and sixth torque-transmitting mechanisms; a second forward speed ratio is established with the engagement of said third and sixth torque-transmitting mechanisms; a third forward speed ratio is established with the engagement of said first and sixth torque-transmitting mechanisms; a fourth forward speed ratio is established with the engagement of said second and sixth torque-transmitting mechanisms; a fifth forward speed ratio is established with the engagement of said second and first torque-transmitting mechanisms; a sixth forward speed ratio is established with the engagement of said second and fourth torque-transmitting mechanisms; and a reverse speed ratio is established with the engagement of said fourth and fifth torque-transmitting mechanisms.
16. The transmission of claim 15 , wherein each of said first members is a ring gear, each of said second members is a planet carrier assembly member, and each of said third members is a sun gear.
17. The transmission of claim 15 , wherein said first, second and third members of said first planetary gear set comprise a sun gear, a planet carrier assembly member and a ring gear, respectively, and said first, second and third members of said second and third planetary gear sets comprise a ring gear, a planet carrier assembly member, and a sun gear, respectively.
18. The transmission of claim 15 , wherein said first, second and third members of said first planetary gear set comprise a planet carrier assembly member, a ring gear, and a sun gear, respectively, and said first, second and third members of said second and third planetary gear sets comprise a ring gear, a planet carrier assembly member, and a sun gear, respectively.
19. A multi-speed transmission comprising:
an input shaft;
an output shaft;
a planetary gear arrangement having first, second and third planetary gear sets, each planetary gear set having a ring gear, a planet carrier assembly member, and a sun gear;
said input shaft being continuously interconnected with said ring gear of said first planetary gear set, and said output shaft being continuously interconnected with said planet carrier assembly member of said second planetary gear set;
a first interconnecting member continuously interconnecting said ring gear of said second planetary gear set with said planet carrier assembly member of said third planetary gear set;
a second interconnecting member continuously interconnecting said sun gear of said second planetary gear set with said sun gear of said third planetary gear set;
said sun gear of said first planetary gear set being continuously connected with a stationary member;
a first torque-transmitting mechanism selectively interconnecting said ring gear of said first planetary gear set with said ring gear of said third planetary gear set;
a second torque-transmitting mechanism selectively interconnecting said ring gear of said first planetary gear set with said ring gear of said second planetary gear set;
a third torque-transmitting mechanism selectively interconnecting said planet carrier assembly member of said first planetary gear set with said planet carrier assembly member of said third planetary gear set;
a fourth torque-transmitting mechanism selectively interconnecting said planet carrier assembly member of said first planetary gear set with said ring gear of said third planetary gear set;
a fifth torque-transmitting mechanism selectively interconnecting said planet carrier assembly member of said third planetary gear set with said stationary member; and
a sixth torque-transmitting mechanism selectively interconnecting said sun gear of said third planetary gear set with said stationary member;
wherein said six torque-transmitting mechanisms are engaged in combinations of two to provide at least one reverse speed ratio and six forward speed ratios.
20. The transmission of claim 19 , wherein a first forward speed ratio is established with the engagement of said fourth and sixth torque-transmitting mechanisms; a second forward speed ratio is established with the engagement of said third and sixth torque-transmitting mechanisms; a third forward speed ratio is established with the engagement of said first and sixth torque-transmitting mechanisms; a fourth forward speed ratio is established with the engagement of said second and sixth torque-transmitting mechanisms; a fifth forward speed ratio is established with the engagement of said second and first torque-transmitting mechanisms; a sixth forward speed ratio is established with the engagement of said second and fourth torque-transmitting mechanisms; and a reverse speed ratio is established with the engagement of said fourth and fifth torque-transmitting mechanisms.