Motor flywheel with integrated magnetic sensor ring

Patent metadata

Field	Value
Publication number	US-2025141315-A1
Application number	US-202318495473-A
Country	US
Kind code	A1
Filing date	Oct 26, 2023
Priority date	Oct 26, 2023
Publication date	May 1, 2025
Grant date	—

Abstract

A motor broadly includes a rotor, a flywheel, and an encoder assembly. The rotor is rotatable about an axis and includes a rotor shaft. The flywheel is fixed to the rotor shaft and is rotatable with the rotor shaft. The encoder assembly includes a magnetic sensor assembly and a sensed magnetic element supported by the flywheel.

First claim

1 . A motor comprising:
a rotor rotatable about an axis and including a rotor shaft; a flywheel fixed to the rotor shaft to rotate therewith; and an encoder assembly including a sensed optical element and a sensed magnetic element, said encoder assembly further including an optical sensor assembly configured to sense relative movement of the optical element and a magnetic sensor assembly configured to sense relative movement of the magnetic element, said sensed elements being mounted on the flywheel for rotational movement therewith, such that the optical sensor assembly and the magnetic sensor assembly are each configured to sense rotation of the flywheel.

2 . The motor as claimed in claim 1 ,
said sensed magnetic element comprising a magnetic ring mounted on the flywheel to rotate therewith, said flywheel including a hub configured to receive the magnetic ring.

3 . The motor as claimed in claim 2 ,
said hub defining an annular recess configured to receive the magnetic ring.

4 . The motor as claimed in claim 2 ,
said magnetic sensor assembly including a magnetic sensing chip, said magnetic ring having an axial ring length, said magnetic sensing chip being positioned axially midway along the axial ring length.

5 . The motor as claimed in claim 4 ,
said encoder assembly including a stationary circuit board mounted adjacent the flywheel and supporting the sensor assemblies.

6 . The motor as claimed in claim 5 ,
said flywheel including a wheel disc and a center wall that cooperatively form the hub, said circuit board positioned to extend radially along the wheel disc and axially overlap the center wall.

7 . The motor as claimed in claim 1 ,
said encoder assembly including a stationary circuit board mounted adjacent the flywheel and supporting the sensor assemblies.

8 . The motor as claimed in claim 7 ,
said flywheel including a wheel disc and a center wall, said circuit board positioned to extend radially along the wheel disc and axially overlap the center wall.

9 . The motor as claimed in claim 8 ,
said optical sensor assembly being located between the circuit board and the wheel disc.

10 . The motor as claimed in claim 9 ,
said sensor assemblies being mounted on opposite sides of the circuit board.

11 . The motor as claimed in claim 1 ,
said flywheel comprising a nonferrous material.

12 . The motor as claimed in claim 11 ,
said nonferrous material comprising a zinc material.

13 . A motor comprising:
a rotor rotatable about an axis and including a rotor shaft; an encoder assembly including a rotatable magnetic ring and a relatively stationary magnetic sensor assembly, said magnetic sensor assembly including a magnetic sensing chip positioned axially along the rotor shaft; and a flywheel fixed to the rotor shaft to rotate therewith, said flywheel including a hub that fixedly supports the magnetic ring in at least partial axial alignment with the magnetic sensing chip such that rotation of the magnetic ring is sensed by the magnetic sensing chip.

14 . The motor as claimed in claim 13 ,
said rotor shaft presenting a shaft end, said hub being configured so that the magnetic ring is positioned along the rotor shaft and spaced inwardly from the shaft end.

15 . The motor as claimed in claim 13 ,
said magnetic ring having an axial ring length, said magnetic sensing chip being positioned axially midway along the axial ring length.

16 . The motor as claimed in claim 13 ,
said hub defining an annular recess configured to receive the magnetic ring.

17 . The motor as claimed in claim 13 ,
said encoder assembly including a stationary circuit board mounted adjacent the flywheel and supporting the magnetic sensor assembly.

18 . The motor as claimed in claim 17 ,
said flywheel including a wheel disc and a center wall that cooperatively form the hub, said circuit board positioned to extend radially along the wheel disc and axially overlap the center wall, said circuit board being located between the magnetic sensor assembly and the wheel disc.

Assignees

• Nidec Motor Corp

Inventors

• Biro Joshua M
• Moore William D

Classifications

• H02K11/22

  Optical devices · CPC title

• H02K7/02

  Additional mass for increasing inertia, e.g. flywheels · CPC title

• H02K2211/03

  Machines characterised by circuit boards, e.g. pcb · CPC title

• H02K11/215 Primary

  Magnetic effect devices, e.g. Hall-effect or magneto-resistive elements · CPC title