Electric power steering system and brush motor thereof

Patent metadata

Field	Value
Publication number	US-10879774-B2
Application number	US-201715696744-A
Country	US
Kind code	B2
Filing date	Sep 6, 2017
Priority date	Sep 9, 2016
Publication date	Dec 29, 2020
Grant date	Dec 29, 2020

Abstract

An electric power steering system and its brush motor are disclosed. The brush motor includes a stator and a rotor rotatably mounted to the stator. The rotor includes a rotary shaft, a commutator and a rotor core fixed to the rotary shaft, and a rotor winding wound around the rotor core. The commutator includes a plurality of commutator segments. The rotor core includes a plurality of teeth. The rotor winding includes a plurality of winding elements. Adjacent teeth define therebetween wire slots for receiving the winding elements. The winding elements include a plurality of first winding elements and a plurality of second winding elements. The first winding elements are connected in series through the commutator segments. The second winding elements are connected in series through the commutator segments. The first winding elements and the second winding elements are received in different wire slots. Implementation of the present invention can improve the reliability of the product.

First claim

The invention claimed is:

1. A brush motor comprising:
a stator comprising a plurality of electric brushes; and
a rotor rotatably mounted to the stator, the rotor comprising:
a rotary shaft,
a commutator and a rotor core fixed to the rotary shaft, the commutator comprising a plurality of commutator segments, the electric brushes configured to be in contacting with at least some of the commutator segments, the rotor core comprising a plurality of teeth, adjacent teeth defining therebetween wire slots; and
a rotor winding wound around the rotor core and comprising a plurality of winding elements, the winding elements comprising a plurality of first winding elements and a plurality of second winding elements received in the wire slots, the first winding elements being connected in series through the commutator segments to form a first closed loop, the second winding elements being connected in series through the commutator segments to form a second closed loop, the first closed loop be not electrically connected with the second closed loop when the electric brush being not contacting with the commutator segments, and the first winding elements and the second winding elements being received in different wire slots.

2. The brush motor according to claim 1 , wherein for any two adjacent wire slots, one wire slot is configured to receive one of the first winding elements, and the other wire slot is configured to receive one of the second winding elements.

3. The brush motor according to claim 1 , wherein for any two adjacent commutator segments, one commutator segment is electrically connected with one of the first winding elements, and the other commutator segment is electrically connected with one of the second winding elements.

4. The brush motor according to claim 3 , wherein the first winding elements are formed by continuously winding a single wire, and the second winding elements are formed by continuously winding a single wire.

5. The brush motor according to claim 3 , wherein the number of the commutator segments of the commutator is an even number, and the number of the teeth of the rotor core is an even number.

6. The brush motor according to claim 5 , wherein the number of the commutator segments is equal to the number of the teeth.

7. The brush motor according to claim 5 , wherein a span length of the winding element is an even number.

8. The brush motor according to claim 5 , wherein in various winding elements formed by winding the same wire, adjacent ones are offset by two wire slots along a circumferential direction of the rotor and by two commutator segments along the circumferential direction of the rotor.

9. The brush motor according to claim 1 , wherein a difference between a span length of each winding element and a pole pitch calculated in terms of the number of the teeth of the rotor is no greater than 1, and two leading-out ends of each winding element are directly connected to two of the commutator segments, respectively.

10. The brush motor according to claim 1 , wherein two leading-out ends of each winding element are directly connected to two of the commutator segments, and a difference between a commutator pitch of each winding element and two times of a pole pitch calculated in terms of the number of the commutator segments is no greater than 2.

11. The brush motor according to claim 10 , wherein the difference between the commutator pitch of each winding element and two times of the pole pitch calculated in terms of the number of the commutator segments is equal to 1.

12. The brush motor according to claim 1 , wherein the commutator segments are evenly arranged along a circumferential direction of the commutator, with a spacing formed between adjacent two commutator segments, a size of each electric brush in a circumferential direction of the commutator is configured to enable the electric brush to at least contact two adjacent commutator segments at any given time.

13. The brush motor according to claim 1 , wherein the number of the stator poles of the stator, the number of the commutator segments and the number of the wire slots of the rotor are one of the following combinations:
the stator has 4 stator poles, the number of the commutator segments is 22, and the number of the wire slots is 22;
the stator has 4 stator poles, the number of the commutator segments is 18, and the number of the wire slots is 18;
the stator has 4 stator poles, the number of the commutator segments is 14, and the number of the wire slots is 14; and
the stator has 6 stator poles, the number of the commutator segments is 20, and the number of the wire slots is 20.

14. An electric power steering system comprising:
a torque sensor;
an electronic control unit connected to the torque sensor; and
a brush motor configured as an assisting motor under the control of the electronic control unit, the brush motor comprising:
a stator; and
a rotor rotatably mounted to the stator, the rotor comprising:
a rotary shaft,
a commutator and a rotor core fixed to the rotary shaft, the commutator comprising a plurality of commutator segments, the rotor core comprising a plurality of teeth, adjacent teeth defining therebetween wire slots; and
a rotor winding wound around the rotor core and comprising a plurality of winding elements, the winding elements comprising a plurality of first winding elements and a plurality of second winding elements received in the wire slots, the first winding elements being connected in series through the commutator segments to form a first closed loop, the second winding elements being connected in series through the commutator segments to form a second closed loop, and the first winding elements and the second winding elements being received in different wire slots.

15. The electric power steering system according to claim 14 , wherein each of the first winding elements is not electrically connected with any of the second winding elements when the electric brush is not contacting with the commutator segments.

Assignees

• Johnson Electric Sa
• Johnson Electric Int Ag

Inventors

• Qin Rui Feng
• Liu Fei

Classifications

• B62D5/04

  electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear · CPC title

• H02K3/28

  Layout of windings or of connections between windings (windings for pole-changing H02K17/06, H02K17/14, H02K19/12, H02K19/32) · CPC title

• H02K3/48

  in slots · CPC title

• H02K23/36 Primary

  having two or more windings; having two or more commutators; having two or more stators · CPC title

• H02K13/10

  Arrangements of brushes or commutators specially adapted for improving commutation · CPC title