Multi-speed planetary transmission

Patent metadata

Field	Value
Publication number	US-10260599-B2
Application number	US-201615278343-A
Country	US
Kind code	B2
Filing date	Sep 28, 2016
Priority date	Sep 28, 2016
Publication date	Apr 16, 2019
Grant date	Apr 16, 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; 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 fixedly coupled to a first ring gear of the plurality of planetary gearsets, the plurality of selective couplers are selectively engageable 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 four of the plurality of selective couplers engaged, the plurality of selective couplers including a first selective coupler which, when engaged, fixedly couples a first sun gear of the plurality of planetary gearsets to the at least one stationary member and a second selective coupler which, when engaged, fixedly couples a first one of the sun gear of the first planetary gearset, the planet carrier of the first planetary gearset, and the ring gear of the first planetary gearset to a second one of the sun gear of the first planetary gearset, the planet carrier of the first planetary gearset, and the ring gear of the first planetary gearset, and a first interconnector fixedly couples the planet carrier of the first planetary gearset to the planet carrier of the third planetary gearset.

2. The transmission of claim 1 , wherein the output member is fixedly coupled to a first planet carrier of the plurality of planetary gearsets.

3. The transmission of claim 1 , wherein the plurality of selective couplers includes a first number of clutches and a second number of brakes, the first number being greater than the second number.

4. The transmission of claim 1 , 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.

5. The transmission of claim 4 , wherein the first ring gear of the plurality of planetary gearsets is the ring gear of the first planetary gearset and the output member is fixedly coupled to the planet carrier of the fourth planetary gearset.

6. The transmission of claim 5 , further comprising:
a second interconnector which fixedly couples the planet carrier of the second planetary gearset to the ring gear of the fourth planetary gearset; and
a third interconnector which fixedly couples the sun gear of the second planetary gearset to the sun gear of the third planetary gearset.

7. The transmission of claim 6 , wherein the first sun gear is the sun gear of the second planetary gearset and the plurality of selective couplers includes:
the first selective coupler which, when engaged, further fixedly couples the sun gear of the third planetary gearset to the at least one stationary member;
a third selective coupler which, when engaged, fixedly couples the ring gear of the second planetary gearset to the at least one stationary member;
a fourth selective coupler which, when engaged, fixedly couples the ring gear of the third planetary gearset to the planet carrier of the second planetary gearset and to the ring gear of the fourth planetary gearset;
a fifth selective coupler which, when engaged, fixedly couples the sun gear of the first planetary gearset to the sun gear of the fourth planetary gearset; and
a sixth selective coupler which, when engaged, fixedly couples the ring gear of the third planetary gearset to the sun gear of the fourth planetary gearset.

8. The transmission of claim 7 , wherein the first one of the sun gear of the first planetary gearset, the planet carrier of the first planetary gearset, and the ring gear of the first planetary gearset is the sun gear of the first planetary gearset and the second one of the sun gear of the first planetary gearset, the planet carrier of the first planetary gearset, and the ring gear of the first planetary gearset is the ring gear of the first planetary gearset.

9. The transmission of claim 7 , wherein the at least one stationary member includes a housing, the housing having a first end and a second end, wherein
the input member is accessible proximate the first end of the housing;
the output member is accessible proximate the second end of the housing;
the first planetary gearset is positioned between the first end of the housing and the second planetary gearset;
the second planetary gearset is positioned between the first planetary gearset and the third planetary gearset;
the third planetary gearset is positioned between the second planetary gearset and the fourth planetary gearset; and
the fourth planetary gearset is positioned between the third planetary gearset and the second end of the housing.

10. A transmission comprising:
an input 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; and
an output member operatively coupled to the input member through the plurality of planetary gearsets, wherein the input member is fixedly coupled to the ring gear of one of the plurality of planetary gearsets and a first selective coupler of the plurality of selective couplers fixedly couples at least two of the sun gear, the planet carrier, and the ring gear of the one of the plurality of planetary gearsets together when the first selective coupler is in the engaged configuration.

11. The transmission of claim 10 , wherein the plurality of selective couplers includes a first number of clutches and a second number of brakes, the first number being greater than the second number.

12. The transmission of claim 11 , 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.

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

Assignees

• Allison Transm Inc

Inventors

• Richardson Michael J E
• Horen Jezrah

Classifications

• F16H2200/0069

  the gear ratios comprising ten forward speeds · CPC title

• F16H2200/2012

  with four sets of orbital gears · CPC title

• 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