Ring magnet rotor of motor with coating material

Patent metadata

Field	Value
Publication number	US-10367387-B2
Application number	US-201715427271-A
Country	US
Kind code	B2
Filing date	Feb 8, 2017
Priority date	Dec 17, 2012
Publication date	Jul 30, 2019
Grant date	Jul 30, 2019

Abstract

A rotor of a motor capable of improving durability of the motor by increasing a bonding force between a ring magnet and a resin. The rotor includes a ring magnet having an insertion hole passing through the center thereof, a shaft inserted into the insertion hole, and a resin that is disposed between the insertion hole and the shaft and fixes the ring magnet and the shaft. The resin extends to upper and lower surfaces of the ring magnet so as to cover at least parts of the upper and lower surfaces of the ring magnet.

First claim

What is claimed is:

1. A rotor of a motor comprising:
a shaft;
a resin coupled to the shaft; and
a ferrite magnet including a through hole and coupled to the resin,
wherein the resin covers an inner circumferential surface of the ferrite magnet, an upper surface of the ferrite magnet and a lower surface of the ferrite magnet,
wherein the ferrite magnet includes a plurality of magnet fixing recesses which are disposed on the upper surface of the ferrite magnet and coupled to the resin,
wherein each of the plurality of magnet fixing recesses includes a bottom surface and a side surface, the bottom surface extending perpendicularly from a first end at the inner circumferential surface of the ferrite magnet in a direction away from the shaft to a second end, and the side surface extending from the second end of the bottom surface to the upper surface of the ferrite magnet,
wherein the plurality of magnet fixing recesses widens from the second end of the bottom surface toward the upper surface,
wherein the shaft includes a shaft fixing recess continuously formed in an outer circumferential surface of the shaft, the shaft fixing recess in a bonding surface in contact with the resin, wherein the shaft fixing recess is aligned with the bottom surface of one of the magnet fixing recesses in the direction perpendicular to the inner circumferential surface of the ferrite magnet,
wherein the resin completely fills a space between the shaft fixing recess and the inner circumferential surface of the ferrite magnet, wherein a thickness of the resin provided between the inner circumferential surface of the ferrite magnet and the shaft fixing recess is the same in a radial direction of the shaft, and
wherein a linear distance from a radially outermost surface of the shaft to an outer circumferential surface of the ferrite magnet is greater than a linear distance from the radially outermost surface of the shaft to an outmost end of the side surface of the magnet fixing recess in the radial direction.

2. The rotor of claim 1 , wherein an outer circumferential surface of the ferrite magnet is coated with a coating material.

3. The rotor of claim 2 , wherein the coating material includes Teflon and has a thickness of 10 μm to 30 μm.

4. The rotor of claim 1 , wherein the resin is formed by injection molding.

5. The rotor of claim 1 , wherein a distance from an outermost end of the resin to a radial center of the shaft is greater than a distance from an outermost end of the one of the magnet fixing recesses to the radial center of the shaft.

6. The rotor of claim 1 , wherein each of the magnet fixing recesses has a semicircular shape or a semioval shape.

7. The rotor of claim 1 , wherein an upper surface of the resin covers the upper surface of the ferrite magnet, a lower surface of the resin covers the lower surface of the ferrite magnet, and wherein a height from the upper surface of the resin to the lower surface of the resin is greater than a height of an outer circumferential surface of the ferrite magnet.

8. The rotor of claim 1 , wherein the shaft includes a first region between one end of the shaft and an axial center of the shaft and a second region between the other end of the shaft and the axial center of the shaft, and the ferrite magnet and the resin are disposed only in the first region.

9. The rotor of claim 1 , wherein a shortest distance from the radially outermost surface of the shaft to an outermost side of the resin is longer than a shortest distance from the radially outermost surface of the shaft to an outermost side of the magnet fixing recess and is shorter than the shortest distance from the radially outermost surface of the shaft to an outermost side of the ferrite magnet.

10. The rotor of claim 1 , wherein an upper surface and a lower surface of the resin perpendicular to an outermost circumference of the shaft are entirely flat.

11. The rotor of claim 1 , wherein a diameter of a virtual circle connecting the outmost ends of the side surfaces of the plurality of magnet fixing recesses is smaller than a diameter of the outer circumferential surface of the ferrite magnet.

12. A motor comprising:
a housing;
a stator disposed in the housing; and
a rotor disposed in the stator,
wherein the rotor includes a shaft, a resin coupled to the shaft and a ferrite magnet including a through hole and coupled to the resin,
wherein the resin covers an inner circumferential surface of the ferrite magnet, an upper surface of the ferrite magnet and a lower surface of the ferrite magnet,
wherein the ferrite magnet includes a plurality of magnet fixing recesses which are disposed on the upper surface of the ferrite magnet and into which the resin is inserted,
wherein the magnet fixing recess includes a bottom surface and a side surface, the bottom surface extending perpendicularly from a first end at the inner circumferential surface of the ferrite magnet in a direction away from the shaft to a second end, and the side surface extending from the second end of the bottom surface to the upper surface of the ferrite magnet,
wherein the magnet fixing recess widens from the second end of the bottom surface toward the upper surface,
wherein the shaft includes a shaft fixing recess continuously formed in an outer circumferential surface of the shaft, the shaft fixing recess in a bonding surface in contact with the resin, wherein the shaft fixing recess is aligned with one of the magnetic fixing recesses in the direction perpendicular to the inner circumferential surface of the ferrite magnet,
wherein the resin completely fills a space between the shaft fixing recess and the inner circumferential surface of the ferrite magnet, wherein a thickness of the resin provided between the inner circumferential surface of the ferrite magnet and the shaft fixing recess is the same in a radial direction of the shaft, and
wherein a linear distance from a radially outermost surface of the shaft to an outer circumferential surface of the ferrite magnet is greater than a linear distance from the radially outermost surface of the shaft to an outmost end of the side surface of the magnet fixing recess in the radial direction.

13. The motor of claim 12 , wherein an upper surface and a lower surface of the resin perpendicular to an outermost circumference of the shaft are entirely flat.

14. The motor of claim 12 , wherein a diameter of a virtual circle connecting the outmost ends of the side surfaces of the plurality of magnet fixing recesses is smaller than a diameter of the outer circumferential surface of the ferrite magnet.

Assignees

• Lg Innotek Co Ltd

Inventors

• Park Young Il
• Shin Dong Ju

Classifications

• H02K1/27 Primary

  Rotor cores with permanent magnets · CPC title

• H02K1/28 Primary

  Means for mounting or fastening rotating magnetic parts on to, or to, the rotor structures · CPC title

• H02K1/2733

  Annular magnets · CPC title

• H02K1/2726

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

• H02K1/22

  Rotating parts of the magnetic circuit · CPC title