Multi-speed planetary transmission

Patent metadata

Field	Value
Publication number	US-10323722-B2
Application number	US-201615278694-A
Country	US
Kind code	B2
Filing date	Sep 28, 2016
Priority date	Sep 28, 2016
Publication date	Jun 18, 2019
Grant date	Jun 18, 2019

Abstract

A multi-speed transmission including a plurality of planetary gearsets and a plurality of selective couplers to achieve at least nine forward speed ratios is disclosed. The plurality of planetary gearsets may include a first planetary gearset, a second planetary gearset, a third planetary gearset, and a fourth planetary gearset. The plurality of selective couplers may include a number of clutches and a number of brakes. The multi-speed transmission may have four planetary gearsets and six selective couplers. The six selective couplers may include four clutches and two brakes.

First claim

What is claimed is:

1. A transmission comprising:
at least one stationary member;
an input member rotatable relative to the at least one stationary member;
a plurality of planetary gearsets operatively coupled to the input member, each planetary gearset of the plurality of planetary gearsets including a sun gear, a plurality of planet gears operatively coupled to the sun gear, a planet carrier operatively coupled to the plurality of planet gears, and a ring gear operatively coupled to the plurality of planet gears, the plurality of planetary gearsets including a first planetary gearset, a second planetary gearset, a third planetary gearset, and a fourth planetary gearset;
a plurality of selective couplers operatively coupled to the plurality of planetary gearsets, each of the plurality of selective couplers having an engaged configuration and a disengaged configuration, the plurality of selective couplers including a first number of clutches and a second number of brakes, the first number being greater than the second number; and
an output member rotatable relative to the at least one stationary member, and operatively coupled to the input member through the plurality of planetary gearsets, wherein the input member is operatively coupled to the plurality of planetary gearsets only through a subset of the first number of clutches, the subset including a first clutch, a second clutch, and a third clutch, wherein
the first clutch, when engaged, fixedly couples the input member to a first group of the plurality of planetary gearsets,
the second clutch, when engaged, fixedly couples the input member to a second group of the plurality of planetary gearsets,
the third clutch, when engaged, fixedly couples the input member to a third group of the plurality of planetary gearsets,
each of the first planetary gearset, the second planetary gearset, the third planetary gearset, and the fourth planetary gearset are included in at least one of the first group of the plurality of planetary gearsets, the second group of the plurality of planetary gearsets, and the third group of the plurality of planetary gearsets, and
the second clutch, when engaged, fixedly couples the input member to the planet carrier of the first planetary gearset and to the planet carrier of the third planetary gearset.

2. The transmission of claim 1 , wherein the first clutch, when engaged, fixedly couples the input member to the planet carrier of the second planetary gearset and to the ring gear of the fourth planetary gearset; and the third clutch, when engaged, fixedly couples the input member to the sun gear of the first planetary gearset.

3. The transmission of claim 1 , wherein the first clutch, when engaged, fixedly couples the input member to the planet carrier of the second planetary gearset and to the planet carrier of the fourth planetary gearset; the second clutch, when engaged, fixedly couples the input member to the planet carrier of the first planetary gearset and to the planet carrier of the third planetary gearset; and the third clutch, when engaged, fixedly couples the input member to the sun gear of the third planetary gearset.

4. The transmission of claim 1 , wherein the first clutch, when engaged, fixedly couples the input member to the ring gear of the third planetary gearset and to the planet carrier of the fourth planetary gearset; the second clutch, when engaged, fixedly couples the input member to the planet carrier of the first planetary gearset and to the planet carrier of the second planetary gearset; and the third clutch, when engaged, fixedly couples the input member to the sun gear of the first planetary gearset.

5. The transmission of claim 1 , wherein the output member is fixedly coupled to the fourth planetary gearset.

6. The transmission of claim 5 , wherein the output member is further fixedly coupled to the third planetary gearset.

7. The transmission of claim 5 , wherein the plurality of selective couplers includes the first clutch, the second clutch, the third clutch, a fourth clutch, a first brake fixedly coupled to the at least one stationary member, and a second brake fixedly coupled to the at least one stationary member.

8. The transmission of claim 7 , wherein each of the first planetary gearset, the second planetary gearset, the third planetary gearset, and the fourth planetary gearset is a simple planetary gearset.

9. The transmission of claim 8 , wherein the plurality of selective couplers are selectively engaged in a plurality of combinations to establish at least nine forward speed ratios and at least one reverse speed ratio between the input member and the output member, each of the plurality of combinations having at least three of the plurality of selective couplers engaged.

10. The transmission of claim 8 , further comprising:
a first interconnector which fixedly couples the sun gear of the fourth planetary gearset, the ring gear of the third planetary gearset, and the ring gear of the second planetary gearset together;
a second interconnector which fixedly couples the planet carrier of the second planetary gearset to the planet carrier of the fourth planetary gearset;
a third interconnector which fixedly couples the sun gear of the first planetary gearset to the sun gear of the second planetary gearset; and
a fourth interconnector which fixedly couples the planet carrier of the first planetary gearset to the planet carrier of the third planetary gearset.

11. The transmission of claim 10 , wherein
the first brake, when engaged, fixedly couples the sun gear of the first planetary gearset and the sun gear of the second planetary gearset to the at least one stationary member;
the second brake, when engaged, fixedly couples the ring gear of the first planetary gearset to the at least one stationary member;
the first clutch, when engaged, fixedly couples the input member to the planet carrier of the second planetary gearset and to the planet carrier of the fourth planetary gearset;
the second clutch, when engaged, fixedly couples the input member to the planet carrier of the first planetary gearset and to the planet carrier of the third planetary gearset;
the third clutch, when engaged, fixedly couples the input member to the sun gear of the third planetary gearset; and
the fourth clutch, when engaged, fixedly couples the ring gear of the first planetary gearset to the sun gear of the third planetary gearset.

12. The transmission of claim 8 , further comprising:
a first interconnector which fixedly couples the ring gear of the third planetary gearset to the planet carrier of the fourth planetary gearset;
a second interconnector which fixedly couples the ring gear of the first planetary gearset to the sun gear of the fourth planetary gearset;
a third interconnector which fixedly couples the sun gear of the second planetary gearset to the sun gear of the third planetary gearset; and
a fourth interconnector which fixedly couples the planet carrier of the first planetary gearset to the planet carrier of the second planetary gearset.

13. The transmission of claim 12 , wherein
the first brake, when engaged, fixedly couples the sun gear of the second planetary gearset and the sun gear of the third planetary gearset to the at least one stationary member;
the second brake, when engaged, fixedly couples the ring gear of the second planetary gearset to the at least one stationary member;
the first clutch, when engaged, fixedly couples the input member to the ring gear of the third planetary gearset and to the planet carrier of the fourth planetary gearset;
the second clutch, when engaged, fixedly couples the input member to the planet

Assignees

• Allison Transm Inc

Inventors

• Schoolcraft Brian
• Raszkowski James

Classifications

• F16H3/66 Primary

  composed of a number of gear trains without drive passing from one train to another · CPC title

• F16H2200/2046

  with six engaging means · CPC title

• F16H2200/0069

  the gear ratios comprising ten forward speeds · CPC title

• F16H2200/2012

  with four sets of orbital gears · CPC title

• F16H2200/0065

  the gear ratios comprising nine forward speeds · CPC title