Brushless motor

Patent metadata

Field	Value
Publication number	US-11075599-B2
Application number	US-201816482567-A
Country	US
Kind code	B2
Filing date	Jan 22, 2018
Priority date	Feb 8, 2017
Publication date	Jul 27, 2021
Grant date	Jul 27, 2021

Abstract

A brushless motor includes: a motor rotor; a stator coil section which has a plurality of energization phases, which includes a first stator coil and a second stator coil that are provided to each phase, and which is arranged to generate a magnetic field, and thereby rotate the motor rotor; and a connection switching section configured to switch a connection of the first stator coil and the second stator coil from a serial connection to a parallel connection, or from the parallel connection to the serial connection.

First claim

The invention claimed is:

1. A brushless motor comprising:
a motor rotor;
a stator coil section which has a plurality of energization phases, which includes a first stator coil and a second stator coil that are provided to each phase, and which is arranged to generate a magnetic field, and thereby rotate the motor rotor; and
a connection switching section configured to switch a connection of the first stator coil and the second stator coil from a serial connection to a parallel connection, or from the parallel connection to the serial connection,
wherein the stator coil section includes a first stator coil section and a second stator coil section; the first stator coil includes a first first stator coil provided to the first stator coil section, and a second first stator coil provided to the second stator coil section; the second stator coil includes a first second stator coil provided to the first stator coil section, and a second second stator coil provided to the second stator coil section; and the connection switching section includes a first connection switching section configured to switch a connection of the first first stator coil and the first second stator coil from the serial connection to the parallel connection, or from the parallel connection to the serial connection, and a second connection switching section configured to switch a connection of the second first stator coil and the second second stator coil from the serial connection to the parallel connection, or from the parallel connection to the serial connection,
wherein the brushless motor includes an energization control section including a first energization control section configured to control energization of the first stator coil section, and a second energization control section configured to control energization of the second stator coil section, a first abnormal state judging section configured to judge whether or not the energization control of the first stator coil section is performed in a normal state, and a second abnormal state judging section configured to judge whether or not the energization control of the second stator coil section is performed in the normal state, and
wherein in a state where the first stator coil section and the second stator coil section are in the parallel connections, when the first abnormal state judging section and the second abnormal state judging section judges that one of the first stator coil section and the second stator coil section is in an abnormal state, one of the first connection switching section and the second connection switching section is configured to switch the other of the first stator coil section and the second stator coil section to the serial connection.

2. The brushless motor as claimed in claim 1 , wherein both end portions of the first stator coil and both end portions of the second stator coil are provided on the same side of the motor rotor in a direction of a rotation axis of the motor rotor.

3. The brushless motor as claimed in claim 1 , wherein the energization control section has a plurality of transistors the connection switching section includes a transistor; and the transistors of the energization control section and the transistors of the connection switching portion are mounted in a same package module.

4. The brushless motor as claimed in claim 1 , wherein the connection switching section includes a serial connection switching section configured to be brought to an energization state to connect the first stator coil and the second stator coil in serial, and a parallel connection switching section configured to be brought to the energization state to connect the first stator coil and the second stator coil in parallel; and
when the connection of the first stator coil and the second stator coil is switched from the parallel connection to the serial connection, the serial connection switching section is brought to the energization state after the parallel connection switching section is brought to a deenergization state.

5. The brushless motor as claimed in claim 1 , wherein the connection switching section includes a serial connection switching section configured to be brought to an energization state to connect the first stator coil and the second stator coil in serial, and a parallel connection switching section configured to be brought to the energization state to connect the first stator coil and the second stator coil in parallel; and
when the connection of the first stator coil and the second stator coil is switched from the serial connection to the parallel connection, the parallel connection switching section is brought to the energization state after the serial connection switching section is brought to a deenergization state.

6. The brushless motor as claimed in claim 1 , wherein the energization control section is configured to vary an energization amount to the stator coil section when the connection switching section switches the connection of the first stator coil and the second stator coil from the serial connection to the parallel connection, or from the parallel connection to the serial connection.

7. The brushless motor as claimed in claim 6 , wherein when the connection switching section switches the connection of the first stator coil and the second stator coil from the serial connection to the parallel connection, or from the parallel connection to the serial connection, the energization control section is configured to gradually vary from a target value of the energization amount before the switching to a target value of the energization amount after the switching.

8. The brushless motor as claimed in claim 1 , wherein the brushless motor is a brushless motor for a power steering device arranged to provide assist force to steered wheels of a vehicle.

9. The brushless motor as claimed in claim 8 , wherein the connection switching section is configured to switch the connection of the first stator coil and the second stator coil in accordance with a vehicle speed.

10. The brushless motor as claimed in claim 8 , wherein the connection switching section is configured to switch the connection of the first stator coil and the second stator coil in accordance with a steering torque.

11. The brushless motor as claimed in claim 8 , wherein the connection switching section is configured to switch the connection of the first stator coil and the second stator coil in accordance with a steering speed.

12. The brushless motor as claimed in claim 1 , wherein the brushless motor is a brushless motor for a brake apparatus arranged to provide a braking force to a braking device for a vehicle; and the connection switching section is configured to switch the connection of the first stator coil and the second stator coil to the serial connection when the braking force is held.

13. The brushless motor as claimed in claim 1 , wherein the connection switching section is configured to switch the connection of the first stator coil and the second stator coil when the energization control section is 0A.

14. A brushless motor comprising:
a motor rotor;
a stator coil section which has a plurality of energization phases, which includes a first stator coil and a second stator coil that are provided to each phase, and which is arranged to generate a magnetic field, and thereby rotate the motor rotor; and
a connection switching section configured to switch a connection of the first stator coil and the second stator coil from a serial connection to a parallel connection, or from the parallel connection to the serial connection,
wherein the stator coil section includes a first stator coil section and a second

Assignees

• Hitachi Automotive Systems Ltd

Inventors

• Shiino Kohtaro
• Sasaki Mitsuo

Classifications

• H02P29/032 Primary

  Preventing damage to the motor, e.g. setting individual current limits for different drive conditions · CPC title

• H02P25/188 Primary

  wherein the motor windings are switched from series to parallel or vice versa to control speed or torque · 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

• B62D5/0484 Primary

  for reaction to failures, e.g. limp home · CPC title

• B62D5/0463

  calculating assisting torque from the motor based on driver input · CPC title