Multi-speed planetary transmission

Patent metadata

Field	Value
Publication number	US-2018347671-A1
Application number	US-201816059810-A
Country	US
Kind code	A1
Filing date	Aug 9, 2018
Priority date	Sep 28, 2016
Publication date	Dec 6, 2018
Grant date	—

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 three clutches and three brakes or four clutches and two brakes.

First claim

What is claimed is:

1 . A transmission comprising:
at least one stationary member; 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, the plurality of selective couplers including a first number of clutches and a second number of brakes; and an output member operatively coupled to the input member through the plurality of planetary gearsets, the output member and the input member are both fixedly coupled to a first one of the first planetary gearset, the second planetary gearset, the third planetary gearset, and the fourth planetary gearset, the input member is fixedly coupled to the plurality of planetary gearsets through a first sun gear of the plurality of planetary gearsets and through a second sun gear of the plurality of planetary gearsets, and the output member is fixedly coupled to a second one of the plurality of planetary gearsets.

2 . The transmission of claim 1 , wherein the first sun gear of the plurality of planetary gearsets is the sun gear of the first planetary gearset and the second sun gear of the plurality of planetary gearsets is the sun gear of the fourth planetary gearset and a sum of the first number and the second number is six.

3 . The transmission of claim 2 , wherein the plurality of selective couplers includes a first clutch, a second clutch, a 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.

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

5 . The transmission of claim 2 , wherein the plurality of selective couplers includes a first clutch, a second clutch, a third clutch, a first brake fixedly coupled to the at least one stationary member, a second brake fixedly coupled to the at least one stationary member, and a third brake fixedly coupled to the at least one stationary member.

6 . The transmission of claim 5 , wherein the first brake, when engaged, fixedly couples the planet carrier of the third planetary gearset to the at least one stationary member.

7 . The transmission of claim 1 , further comprising:
a first interconnector which fixedly couples the ring gear of the first planetary gearset to the planet carrier of the second planetary gearset; and a second interconnector which fixedly couples the ring gear of the second planetary gearset to the sun gear of the third planetary gearset.

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

9 . The transmission of claim 8 , further comprising a sixth selective coupler which, when engaged, fixedly couples the sun gear of the second planetary gearset to the planet carrier of the third planetary gearset.

10 . The transmission of claim 8 , further comprising a sixth selective coupler which, when engaged, fixedly couples the planet carrier of the third planetary gearset to the at least one stationary member.

11 . The transmission of claim 8 , 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.

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 1 , 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.

14 . The transmission of claim 13 , wherein the plurality of selective couplers includes a first brake fixedly coupled to the at least one stationary member, a second brake fixedly coupled to the at least one stationary member, and a third brake fixedly coupled to the at least one stationary member, each of the first brake, the second brake, and the third brake engaged in at least one forward speed ratio of the at least nine forward speed ratios.

15 . The transmission of claim 13 , wherein the plurality of selective couplers includes at least 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, only one of the first brake and the second brake engaged in at least five forward speed ratios of the at least nine forward speed ratios.

Assignees

• Allison Transm Inc

Inventors

• Raszkowski James
• Irving Mitchell
• Crafton Drew A

Classifications

• F16H3/66 Primary

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

• F16H2200/2012

  with four sets of orbital gears · CPC title

• F16H2200/2046

  with six engaging means · CPC title

• F16H2200/0065

  the gear ratios comprising nine forward speeds · CPC title

• F16H2200/0069

  the gear ratios comprising ten forward speeds · CPC title