Electric axle

Patent metadata

Field	Value
Publication number	US-2025035198-A1
Application number	US-202418784614-A
Country	US
Kind code	A1
Filing date	Jul 25, 2024
Priority date	Jul 26, 2023
Publication date	Jan 30, 2025
Grant date	—

Abstract

Methods and systems are provided for an electric axle. The electric axle system includes, in one example, a first electric machine and a planetary reduction differential configured to receive mechanical power from the first electric machine. The planetary reduction differential includes a first planetary gear set directly rotationally coupled to a second planetary gear set. In the electric axle system, a sun gear in the first planetary gear set is directly coupled to an input shaft of the planetary reduction differential.

First claim

1 . An electric axle system, comprising:
a first electric machine; and a planetary reduction differential configured to receive mechanical power from the first electric machine; wherein the planetary reduction differential includes a first planetary gear set directly rotationally coupled to a second planetary gear set; wherein a sun gear in the first planetary gear set is directly coupled to an input shaft of the planetary reduction differential; and wherein a carrier in the first planetary gear set is directly coupled to an output shaft.

2 . The electric axle system of claim 1 , wherein:
the first planetary gear set is a simple planetary gear set and the second planetary gear set is a simple planetary gear set; and/or the first and second planetary gear sets have an identical ring gear to sun gear ratio.

3 . The electric axle system of claim 2 , wherein:
a ring gear in the second planetary gear set is directly coupled to an output shaft; a ring gear in the first planetary gear set is directly rotationally coupled to a sun gear in the second planetary gear set; and a carrier in the second simple planetary gear set is grounded.

4 . The electric axle system of claim 1 , wherein:
the first planetary gear set is a simple planetary gear set and the second planetary gear set is a meshed planet compound planetary gear set; and a ring gear in the second planetary gear set is grounded.

5 . The electric axle system of claim 4 , wherein:
a sun gear in the second planetary gear set is directly coupled to an output shaft; and a ring gear in the first planetary gear set is directly rotationally coupled to a carrier in the second planetary gear set.

6 . The electric axle system of claim 4 , wherein:
a carrier in the second planetary gear set is directly coupled to an output shaft; and a ring gear in the first planetary gear set is directly rotationally coupled to a sun gear in the second planetary gear set.

7 . The electric axle system of claim 1 , wherein:
the first planetary gear set is a meshed planet compound planetary gear set and the second planetary gear set is a meshed planet compound planetary gear set; and a ring gear in the second planetary gear set is grounded.

8 . The electric axle system of claim 7 , wherein:
a sun gear in the second planetary gear set is directly coupled to an output shaft; and a ring gear in the first planetary gear set is directly rotationally coupled to a carrier in the second planetary gear set.

9 . The electric axle system of claim 7 , wherein:
a carrier in the second planetary gear set is directly coupled to an output shaft; and a ring gear in the first planetary gear set is directly rotationally coupled to a sun gear in the second planetary gear set.

10 . The electric axle system of claim 1 , further comprising:
a Ravigneaux three-speed mode planetary gear set rotationally coupled and positioned coaxial to the planetary reduction differential; and
a mode clutch configured to:
ground a carrier or a ring gear in the Ravigneaux three-speed mode planetary gear set, in a first mode;
ground a second sun gear in the Ravigneaux three-speed mode planetary gear set, in a second mode; and
rotationally couple the carrier or a ring gear to the second sun gear in the Ravigneaux three-speed mode planetary gear set, in a third mode;

wherein a first sun gear in the Ravigneaux three-speed mode planetary gear set is rotationally coupled to the first electric machine.

11 . The electric axle system of claim 1 , further comprising:
a two-speed mode planetary gear set rotationally coupled to the input shaft; and a mode clutch configured to:
in a first mode, ground a carrier or a ring gear in the two-speed mode planetary gear set; and
in a second mode, rotationally couple a carrier to the ring gear in the two-speed mode planetary gear set;
wherein a sun gear in the two-speed mode planetary gear set is rotationally coupled to the first electric machine.

12 . The electric axle system of claim 1 , wherein the first electric machine is positioned coaxial, parallel, or transverse, to the planetary reduction differential.

13 . The electric axle system of claim 1 , further comprising a second electric machine rotationally coupled to the planetary reduction differential.

14 . A method for operation of an electric axle, comprising:
operating a first electric machine to deliver mechanical power to a planetary reduction differential; wherein the electric axle includes:
the first electric machine; and
the planetary reduction differential that is configured to receive mechanical power from the first electric machine;
wherein the planetary reduction differential comprises a first planetary gear set directly rotationally coupled to a second planetary gear set; wherein a sun gear in the first planetary gear set is directly coupled to an input shaft of the planetary reduction differential; and wherein a carrier in the first planetary gear set is directly coupled to an output shaft.

15 . The method of claim 14 , further comprising operating a second electric machine to deliver mechanical power to the planetary reduction differential.

16 . The method of claim 14 , further comprising operating a mode clutch in a Ravigneaux three-speed mode planetary gear set that is rotationally coupled to the planetary reduction differential to shift the Ravigneaux three-speed mode planetary gear set between two operating modes included in a set of three operating modes.

17 . An electric axle, comprising:
an electric machine; and a planetary reduction differential configured to receive mechanical power from the electric machine; wherein the planetary reduction differential includes a first planetary gear set directly rotationally coupled to a second planetary gear set; wherein a sun gear in the first planetary gear set is directly coupled to an input shaft of the planetary reduction differential; wherein a carrier in the first planetary gear set is directly coupled to an output shaft; wherein a ring gear in the second planetary gear set is directly coupled to an output shaft; wherein a ring gear in the first planetary gear set is directly rotationally coupled to a sun gear in the second planetary gear set; and wherein a carrier in the second planetary gear set is grounded.

18 . The electric axle of claim 17 , further comprising:
a Ravigneaux three-speed mode planetary gear set rotationally coupled and positioned coaxial to the differential; and a mode clutch configured to selectively transition the Ravigneaux three-speed mode planetary gear set between two of three modes; wherein the mode clutch is configured to:
in a first mode, ground a carrier or a ring gear in the Ravigneaux three-speed mode planetary gear set;
in a second mode, ground a second sun gear in the Ravigneaux three-speed mode planetary gear set; and
in a third mode, rotationally couple the carrier or a ring gear to the second sun gear in the Ravigneaux gear set.

19 . The electric axle of claim 18 , wherein a ring gear or a carrier in the Ravigneaux three-speed mode planetary gear set is coupled to the planetary reduction differential input shaft.

20 . The electric axle of claim 17 , further comprising:
a two-speed planetary gear set directly rotationally coupled to the input shaft; and a mode clutch configured to:
in a first mode, ground a carrier or a ring gear in the two-speed mode planetary gear set; and
in a second mode, rotationally couple a carrier to the

Assignees

• Dana Heavy Vehicle Sys Group

Inventors

• Waltz William F
• David Jeffrey M

Classifications

• F16H2200/2023

  using a Ravigneaux set with 4 connections · CPC title

• F16H2200/2005

  with one sets of orbital gears · CPC title

• F16H2200/0034

  the gear ratios comprising two forward speeds · CPC title

• F16H2200/0021

  specially adapted for electric vehicles · CPC title

• F16H2048/106

  characterised by two sun gears · CPC title