Motor

Patent metadata

Field	Value
Publication number	US-10177625-B2
Application number	US-201615168351-A
Country	US
Kind code	B2
Filing date	May 31, 2016
Priority date	Jun 3, 2015
Publication date	Jan 8, 2019
Grant date	Jan 8, 2019

Abstract

A motor includes a rotating portion. The rotating portion includes a shaft, a rotor hub, and a flywheel. The rotor hub is arranged to extend in an annular shape around the shaft. The flywheel is arranged axially above the rotor hub. The rotor hub includes a joining portion fixed to an outer circumferential surface of the shaft. A center of gravity of the rotating portion and the joining portion of the rotor hub are arranged to radially overlap with each other. The center of gravity of the rotating portion is arranged axially above a radial bearing portion and at a level equivalent to the level of the joining portion.

First claim

What is claimed is:

1. A motor comprising:
a stationary portion; and
a rotating portion supported to be rotatable about a central axis extending in a vertical direction with respect to the stationary portion; wherein
the rotating portion includes:
a shaft arranged to extend along the central axis;
a rotor hub arranged to extend in an annular shape around the shaft; and
a flywheel arranged axially above the rotor hub;

the stationary portion includes a sleeve arranged to rotatably support the shaft;
the motor further comprises a radial bearing portion where the sleeve and the shaft are arranged radially opposite to each other with a lubricating oil arranged therebetween;
the rotor hub includes a joining portion fixed to an outer circumferential surface of the shaft axially above the radial bearing portion; and
a center of gravity of the rotating portion and the joining portion are arranged to radially overlap with each other.

2. The motor according to claim 1 , wherein
the rotating portion further includes an annular inertia portion; and
the inertia portion is arranged to have a predetermined gravity greater than a predetermined gravity of the flywheel.

3. The motor according to claim 2 , wherein at least a portion of the inertia portion and at least a portion of the joining portion are arranged to radially overlap with each other.

4. The motor according to claim 2 , wherein at least a portion of the inertia portion and at least a portion of the radial bearing portion are arranged to radially overlap with each other.

5. The motor according to claim 2 , wherein the inertia portion is arranged to have a mass greater than a mass of the flywheel.

6. The motor according to claim 2 , wherein the flywheel is made of a resin, while the inertia portion is made of a metal.

7. The motor according to claim 2 , wherein
the rotor hub includes:
a cylindrical portion arranged to extend in an axial direction, and arranged radially inward of the inertia portion; and
a flange portion arranged to extend radially outward from the cylindrical portion axially below the inertia portion; and

a lower surface of the inertia portion is arranged to be in contact with an upper surface of the flange portion.

8. The motor according to claim 2 , wherein the flywheel includes a wall portion arranged to cover at least a portion of an outer circumferential surface of the inertia portion.

9. The motor according to claim 8 , wherein the wall portion is arranged to cover the outer circumferential surface of the inertia portion from an upper end to a lower end thereof, and at least a portion of an outer circumferential surface of the rotor hub.

10. The motor according to claim 1 , wherein the flywheel is arranged to have an outside diameter greater than an outside diameter of the rotor hub.

11. The motor according to claim 1 , wherein the flywheel is arranged to have an axial dimension greater than an axial distance from a lower end surface of the stationary portion to an upper end surface of the rotor hub.

12. The motor according to claim 1 , wherein
the radial bearing portion includes:
an upper radial bearing portion; and
a lower radial bearing portion arranged axially below the upper radial bearing portion; and

the upper radial bearing portion is arranged to have an axial dimension greater than an axial dimension of the lower radial bearing portion.

13. The motor according to claim 1 , further comprising a thrust bearing portion where the stationary portion and the rotating portion are arranged axially opposite to each other with the lubricating oil arranged therebetween.

14. The motor according to claim 13 , wherein
the rotating portion further includes a thrust plate arranged to extend radially outward from a lower end of the shaft, and including an upper surface arranged axially opposite to a lower surface of the sleeve;
the thrust bearing portion is defined between the lower surface of the sleeve and the upper surface of the thrust plate; and
a gap including the radial bearing portion and the thrust bearing portion is continuously filled with the lubricating oil.

15. The motor according to claim 13 , wherein
the rotor hub further includes an annular portion arranged around the shaft, and including a lower surface arranged axially opposite to an upper surface of the sleeve;
the thrust bearing portion is defined between the upper surface of the sleeve and the lower surface of the annular portion; and
a gap including the radial bearing portion and the thrust bearing portion is continuously filled with the lubricating oil.

16. The motor according to claim 15 , wherein the center of gravity of the rotating portion is arranged axially above the thrust bearing portion.

17. The motor according to claim 1 , wherein the shaft is press fitted radially inside of the joining portion, with an adhesive arranged between the shaft and the joining portion.

18. The motor according to claim 1 , wherein the rotating portion further includes a mirror supported by the flywheel.

Assignees

• Nidec Corp

Inventors

• Sekii Yoichi
• Nagasawa Naohiro

Classifications

• H02K7/02 Primary

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

• Y02E60/16

  Mechanical energy storage, e.g. flywheels or pressurised fluids · CPC title

• H02K7/085

  radially supporting the rotary shaft at only one end of the rotor (H02K7/086, H02K7/09 take precedence) · CPC title