Electric motor and magnetic core thereof

Patent metadata

Field	Value
Publication number	US-10637307-B2
Application number	US-201715858873-A
Country	US
Kind code	B2
Filing date	Dec 29, 2017
Priority date	Dec 29, 2016
Publication date	Apr 28, 2020
Grant date	Apr 28, 2020

Abstract

A magnetic core of an electric motor includes a central portion and a plurality of teeth extending outwardly from the central portion, the teeth disposed along a circumferential direction of the central portion. Each tooth includes a tooth body, two neck portions and two crown portions, the neck portions respectively connecting the crown portions to the tooth body, the two crown portions respectively extending beyond opposite sides of the tooth body. Each of the two neck portions of each tooth has a minimum width which is 0.1˜0.3 times of the width of the tooth body. The present invention further provides an electric motor that employs the magnetic core which can increase the peak value of the cogging torque of the motor.

First claim

The invention claimed is:

1. A rotor magnetic core of an electric motor, comprising:
a central portion, and
a plurality of teeth extending outwardly from the central portion in respective longitudinal directions, the teeth disposed along a circumferential direction of the central portion;
wherein each tooth comprises a tooth body, two neck portions and two crown portions, the tooth body having a transverse width in a direction perpendicular to the longitudinal direction of the tooth body, the neck portions extending from an outer end of the tooth body in their respective longitudinal directions and bifurcated from each other, each neck portion having a transverse width in a direction perpendicular to the longitudinal direction of said each neck portion, the two crown portions being respectively connected to ends of the neck portions far away from the tooth body, and extending towards opposite sides of the tooth body in circumferential directions; and
wherein a minimum of the transverse width of each neck portions is 0.1˜0.3 times of the transverse width of one of the tooth body, on which said each neck portion depends, and a recess is formed between the two crown portions of each tooth of the rotor magnetic core, the recess having an opening with a width which is 0.6˜0.8 times of the width of the tooth body of the tooth of the rotor magnetic core; and
wherein the rotor magnetic core further comprises a plurality of separation members extending outwardly from the central portion, each separation member being disposed between adjacent two tooth bodies and having a radial length which is less than a radial length of the tooth body.

2. The rotor magnetic core of claim 1 , wherein a recess is formed between the two crown portions of each tooth, the recess having a radial depth which is 0.7˜1.8 times of the width of the opening of the recess.

3. The rotor magnetic core of claim 1 , wherein a recess is formed between the two crown portions of each tooth, the recess being U-shaped, V-shaped or square-shaped.

4. The rotor magnetic core of claim 1 , wherein the two crown portions of each tooth are connected together to form an integral crown.

5. The rotor magnetic core of claim 1 , wherein the central portion defines a mounting hole for allowing a rotating shaft to be mounted therein, and a plurality of anti-slipping grooves is formed in an inner wall of the central portion surrounding the mounting hole.

6. An electric motor, comprising:
a stator, the stator comprising a housing and at least one permanent magnet mounted to an inner surface of the housing;
a rotor comprising a rotating shaft and a rotor magnetic core fixedly mounted on the rotating shaft, the rotating shaft being rotatably mounted to the stator so that the rotor is capable of rotating relative to the stator and the rotor magnetic core being received in the housing and comprising:
a central portion, and
a plurality of teeth extending outwardly from the central portion, the teeth disposed along a circumferential direction of the central portion;
wherein each tooth comprises a tooth body, two neck portions and two crown portions, the tooth body having a transverse width in a direction perpendicular to the longitudinal direction of the tooth body, the neck portions extending from an outer end of the tooth body in their respective longitudinal directions and bifurcated with each other, each neck portion having a transverse width in a direction perpendicular to the longitudinal direction of said each neck portion, the two crown portions respectively connected to ends of the neck portions far away from the tooth body, and extending towards opposite sides of the tooth body in circumferential directions; and
wherein a minimum of the transverse width of each neck portions is 0.1˜0.3 times of the transverse width of one of the tooth body, on which said each neck portion depends, and a recess is formed between the two crown portions of each tooth of the rotor magnetic core, the recess having an opening with a width which is 0.6˜0.8 times of the width of the tooth body of the tooth of the rotor magnetic core;
wherein the rotor magnetic core further comprises a plurality of separation members extending outwardly from the central portion, each separation member being disposed between adjacent two tooth bodies and having a radial length which is less than a radial length of the tooth body.

7. The electric motor of claim 6 , wherein a ratio of an inner diameter of the housing to an outer diameter of the housing is less than 0.93.

8. The electric motor of claim 6 , wherein an outer diameter of the rotor magnetic core is 0.6˜0.8 times of an inner diameter of the housing.

9. The electric motor of claim 6 , wherein the at least one permanent magnet has a magnetic energy product greater than 4 MGOe.

10. The electric motor of claim 6 , wherein the electric motor is a 2-pole 3-slot motor.

11. The electric motor of claim 6 , wherein a peak value of cogging torque of the electric motor is in the range of 8˜14 mNm.

Assignees

• Johnson Electric Sa
• Johnson Electric Int Ag

Inventors

• Li Yue
• Jiang Maoxiong
• Zhou Chuiyou
• Wang Yong
• Zhu Xiaoning
• Li Guihua
• Zhang Yonggang

Classifications

• H02K1/2726

  the rotor consisting of a single magnet or two or more axially juxtaposed single magnets · CPC title

• H02K2213/03

  Machines characterised by numerical values, ranges, mathematical expressions or similar information · CPC title

• H02K2201/03

  Machines characterised by aspects of the air-gap between rotor and stator · CPC title

• H02K1/17 Primary

  Stator cores with permanent magnets · CPC title

• H02K5/161

  radially supporting the rotary shaft at both ends of the rotor (H02K5/165, H02K5/167, H02K5/173 take precedence) · CPC title