WO2019042387A1

WO2019042387A1 - Electric axle assembly

Info

Publication number: WO2019042387A1
Application number: PCT/CN2018/103422
Authority: WO
Inventors: Dean Gao; Shengli HU; Songlin TAN; Qinggang SHAO
Original assignee: Dongfeng Dana Axle Co., Ltd.
Priority date: 2017-08-31
Filing date: 2018-08-31
Publication date: 2019-03-07
Also published as: JP2020531335A

Abstract

An electric axle assembly comprises an electric motor including an output shaft having a first gear disposed thereon, an idler assembly including an idler shaft disposed substantially parallel to the output shaft of the electric motor, the idler shaft having a second gear and a third gear disposed thereon, wherein the second gear is in rotational engagement with the first gear of the electric motor. A differential casing having a fourth gear coupled thereto is in rotational engagement with the idler assembly via the third and fourth gears. The differential casing houses fifth and sixth gears which are coupled to respective first and second half axles of the electric axle assembly to cause a rotational movement thereof.

Description

ELECTRIC AXLE ASSEMBLY

CROSS REFERENCE TO RELATED APPLICATION

This application is entitled to claim the benefit of, and claims priority to, Chinese utility model application no. CN201721108029.7 filed August 31, 2017 and Chinese invention application no. CN201710774408.8 filed August 31, 2017, the entire disclosures of which are incorporated herein by reference.

FIELD

This present disclosure relates to automobile manufacturing, and more particularly, to an electric axle assembly.

BACKGROUND

Presently, most electric vehicles are used in power transmission structure of a conventional internal combustion engine vehicle, comprising a drive motor, drive shaft, a reducer or differential assembly, an axle and a wheel axle end. A conventional design results in a longer chain drive and various components of which takes up a larger portion of space in the vehicle such as a passenger compartment, for example, and the larger size of the conventional design decreases a fuel efficiency of the vehicle.

Accordingly, it would be desirable to provide an apparatus that overcomes the deficiencies of the known designs.

SUMMARY

In concordance and agreement with the present disclosure, an electric axle assembly includes an electric motor, an idler assembly, a differential case, and first and second half axles having a compact arrangement. Such compact arrangement of the electric axle assembly can improve a fuel efficiency of the vehicle, enhance a capacity of a passenger compartment, and increase a capacity of a battery compartment. Additionally, the electric axle assembly of the present disclosure reduces an energy consumption per unit mass of a carrier.

In one embodiment, an electric axle assembly, comprises: an electric motor including an output shaft having a first gear disposed thereon; and an idler assembly including an idler shaft having a second gear disposed thereon, wherein the second gear is in rotational engagement with the first gear, and wherein the idler shaft is disposed substantially parallel to the output shaft of the electric motor.

In certain aspects of the present disclosure, the idler assembly further includes a third gear disposed thereon.

In certain aspects of the present disclosure, the electric axle assembly further comprises a differential case in rotational engagement with the idler assembly via at least one of the third gear and a fourth gear.

In certain aspects of the present disclosure, at least one of the third gear and the fourth gear is a helical gear.

In certain aspects of the present disclosure, the electric axle assembly further comprises a first half axle and a second half axle.

In certain aspects of the present disclosure, the first half axle is in rotational engagement with a fifth gear disposed within the differential case, and the second half axle is in rotational engagement with a sixth gear disposed within in the differential case.

In certain aspects of the present disclosure, the first half axle, the second half axle, and the output shaft of the electric motor are coaxially disposed.

In certain aspects of the present disclosure, the second half axle is at least partially disposed in the output shaft of the electric motor.

In certain aspects of the present disclosure, the electric axle assembly further comprises a first axle housing having at least one of the idler assembly, the differential case, and a portion of the output shaft of the electric motor disposed therein.

In certain aspects of the present disclosure, the electric axle assembly further comprises a second axle housing having at least one of the electric motor and another portion of the output shaft of the electric motor disposed therein.

In certain aspects of the present disclosure, at least one of the idler assembly, the differential case, and the portion of the output shaft of the electric motor is rotatably supported in the first axle housing by at least one bearing.

In certain aspects of the present disclosure, the first axle housing includes at least one recess formed therein to receive the at least one bearing.

In certain aspects of the present disclosure, at least one of the electric motor and the another portion of the output shaft of the electric motor is rotatably supported in the second axle housing by at least one bearing.

In certain aspects of the present disclosure, the second axle housing includes at least one recess formed therein to receive the at least one bearing.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are incorporated herein as part of the specification. The drawings described herein illustrate embodiments of the presently disclosed subject matter, and are illustrative of selected principles and teaching of the present disclosure. However, the drawings do not illustrate all possible implementations of the presently disclosed subject matter, and are not intended to limit the scope of the present disclosure in any way.

FIG. 1 is a cross-sectional view of an electric axle assembly in accordance with the present disclosure.

DETAILED DESCRIPTION

It is to be understood that the present disclosure may assume various alternative orientations and step sequences, except where expressly specified to the contrary. It is also to be understood that the specific assemblies and processes illustrated in the attached drawings, and described in the following specification are simply exemplary embodiments of the inventive concepts defined herein. Hence, specific dimensions, directions, or other physical characteristics relating to the embodiments disclosed are not to be considered as limiting, unless expressly stated otherwise. Also, although they may not be, like elements in various embodiments may be commonly referred to with like reference numerals within this section of the application.

Embodiments of an electric axle assembly 100 are described below. In certain embodiments, the electric axle assembly 100 is utilized with a pure electric vehicle (shown in Fig. 1) where the electric axle assembly 100 is the only driving axle. In other embodiments, the electric axle assembly 100 is utilized with a hybrid four-wheel drive vehicle (not depicted) where a front axle is driven by an internal combustion engine and the rear axle is the electric axle assembly 100. In still other embodiments, the electric axle assembly 100 is utilized with a hybrid commercial vehicle (not depicted) comprising a tandem axle in which a front tandem axle is driven by an internal combustion engine, and a rear tandem axle is the electric axle assembly 100 (or vice versa) . The electric axle assembly 100 may have applications in commercial vehicles, both light duty and heavy duty vehicles, and for passenger, off-highway, and sport utility vehicles. Additionally, the electric axle assembly 100 described herein may be adapted for use in front and/or rear driving axles, and in steerable and non-steerable axles. It would be understood by one of ordinary skill in the art that the electric axle assembly 100 also has industrial, locomotive, military, agricultural, and aerospace applications.

In certain embodiments illustrated in Fig. 1, the electric axle assembly 100 includes an electric motor 1 (e.g., an electromotor) , an idler assembly 2, and a differential 3. Typically, the electric motor 1 is coupled with a power source (not depicted) . The electric motor 1 may be a permanent magnet synchronous machine comprising a stator 1a disposed concentrically about a rotor 1 b. The electric axle assembly 100 may additionally comprise an inverter (not depicted) for converting direct current to alternating current when the electric motor 1 is utilized to drive the vehicle, and for converting alternating current to direct current when the vehicle decelerates. The electric motor 1 may be referred to herein as a motor-generator. Further, the electric axle assembly 100 may include cooling fluid (not depicted) such as, be not limited to, automatic transmission fluid or axle oil integrated with the electric axle assembly 100 for cooling the electric motor 1 and the inverter. In another embodiment, the cooling fluid for the electric motor 1 and the inverter may not be integrated with the axle oil. The electric motor 1 may have either a co-axial (as shown) or off-axis layout where the axle shaft connecting the wheel to a differential 3 does not pass through a center of the electric motor 1 but rather parallel to a central axis of the electric motor 1.

As shown in Fig. 1, the electric axle assembly 100 further includes a left or first half axle 4 and a right or second half axle 5 disposed in a left or first axle housing 6 and a right or second axle housing 7, respectively. The electric motor 1 and the at least a portion of the output shaft 101 are also disposed in the second axle housing 7 between a wheel end (not depicted) of the first half axle 4 and a wheel end (not depicted) of the second half axle 5.

A first gear 8 is coupled with an electric motor output shaft 101. In certain embodiments, the second axle housing 7 includes at least one recess formed therein to receive a portion of at least one bearing 103 used to support the second half axle 5 and the output shaft 101. The electric motor 1 drives the idler assembly 2 via the output shaft 101 and the first gear 8. The idler assembly 2 includes an idler shaft 102. In the illustrated embodiment, the idler shaft 102 of the idler assembly 2 is disposed substantially parallel with the output shaft 101 of the electric motor 1. The idler shaft 102 is rotatably supported in the first axle housing 6 via

bearings

104a, 104b, 104c. It is understood that each of the

bearings

104a, 104b, 104c can be any type of bearing as desired such as a roller bearing, a ball bearing, a tapered bearing, and the like, for example. A second or idler gear 9 is coupled for rotation with the idler shaft 102. The second gear 9 is disposed axially adjacent at least one of the

bearings

104a, 104b, 104c. The second gear 9 is in meshed engagement with the first gear 8 and receives torque therefrom when the electric motor 1 drives the output shaft 101.

A two-stage active or third gear 10 is coupled for rotation with the idler shaft 102. In certain embodiments, the third gear 10 is a helical gear. The third gear 10 is disposed axially adjacent at least one of the

bearings

104a, 104b, 104c. The third gear 10 is in meshed engagement with a driven or fourth gear 11. In certain embodiments, the fourth gear 11 is a helical gear. The fourth gear 11 is coupled for rotation with a differential case 12. The differential case 12 is rotatably supported within the first axle housing 6 via

bearings

106a, 106b. It is understood that each of the

bearings

106a, 106b can be any type of bearing as desired such as a roller bearing, a ball bearing, a tapered bearing, and the like, for example. In certain embodiments, the first axle housing 6 includes at least one recess 108 formed therein to receive at least a portion of at least one of the

bearings

104a, 104b, 104c, 106a, 106b.

As illustrated, the differential case 12 houses two or more differential pinions 13. The differential pinions 13 are coupled with the differential case 12 via a pinion shaft 107. In an embodiment, the pinion shaft 107 may comprise a cross member. The differential pinions 13 are in meshed engagement with a first side or fifth gear 14 and a second side or sixth gear 15. The fifth gear 14 is coupled with the first half axle 4 extending to the wheel end thereof. The sixth gear 15 is coupled to the second half axle 5 extending through a central bore formed in the output shaft 101 of the electric motor 1 to the wheel end thereof. In certain embodiments, the first half axle 4, the wheel end of the first half axle 4, the second half axle 5, the wheel end of the second half axle 5, and the output shaft 101 are coaxially disposed. As shown, the idler assembly 2, the differential 3, the

gears

9, 10, 11, 13, 14, 15 and the differential case 12 are disposed within the first axle housing 6.

In operation, the electric motor 1 outputs torque to the idler shat 102 via meshed engagement of the first and second gears 8, 9. Substantially simultaneously, the idler shaft 102 transfers torque from the electric motor 1 to the third gear 10. The third gear 10 transfers torque from the idler shaft 102 to the differential case 12 via the meshed engagement of the third gear 10 and the fourth gear 11. The differential case 12 then transfers torque to the first and second half axles 4, 5 via the fifth and

sixth gears

14, 15. When the electric axle assembly 100 is in a power generation mode, the torque transfer described above is reversed.

In accordance with the provisions of the patent statutes, the present disclosure of the subject matter has been described in what is considered to represent its preferred embodiments. However, it should be noted that the subject matter can be practiced otherwise than as specifically illustrated and described without departing from its spirit or scope.

Claims

An electric axle assembly, comprising:

an electric motor including an output shaft having a first gear disposed thereon; and

an idler assembly including an idler shaft having a second gear disposed thereon, wherein the second gear is in rotational engagement with the first gear, and wherein the idler shaft is disposed substantially parallel to the output shaft of the electric motor.
The electric axle assembly according to Claim 1, wherein the idler assembly further includes a third gear disposed thereon.
The electric axle assembly according to Claim 2, further comprising a differential case in rotational engagement with the idler assembly via at least one of the third gear and a fourth gear.
The electric axle assembly according to Claim 3, wherein at least one of the third gear and the fourth gear is a helical gear.
The electric axle assembly according to Claim 2, further comprising a first half axle and a second half axle.
The electric axle assembly according to Claim 5, wherein the first half axle isin rotational engagement with a fifth gear disposed within the differential case, and the second half axle is in rotational engagement with a sixth gear disposed within in the differential case.
The electric axle assembly according to Claim 6, wherein the first half axle, the second half axle, and the output shaft of the electric motor are coaxially disposed.
The electric axle assembly according to Claim 5, wherein the second half axle is at least partially disposed in the output shaft of the electric motor.
The electric axle assembly according to Claim 2, further comprising a first axle housing having at least one of the idler assembly, the differential case, and a portion of the output shaft of the electric motor disposed therein.
The electric axle assembly according to Claim 9, further comprising a second axle housing having at least one of the electric motor and another portion of the output shaft of the electric motor disposed therein.
The electric axle assembly according to Claim 9, wherein at least one of the idler assembly, the differential case, and the portion of the output shaft of the electric motor is rotatably supported in the first axle housing by at least one bearing.
The electric axle assembly according to Claim 11, wherein the first axle housing includes at least one recess formed therein to receive the at least one bearing.
The electric axle assembly according to Claim 10, wherein at least one of the electric motor and the another portion of the output shaft of the electric motor is rotatably supported in the second axle housing by at least one bearing.
The electric axle assembly according to Claim 13, wherein the second axle housing includes at least one recess formed therein to receive the at least one bearing.