Rotor and brushless motor

Patent metadata

Field	Value
Publication number	US-11757315-B2
Application number	US-202117458546-A
Country	US
Kind code	B2
Filing date	Aug 27, 2021
Priority date	Aug 31, 2020
Publication date	Sep 12, 2023
Grant date	Sep 12, 2023

Abstract

A rotor applied to an inner rotor brushless motor includes: a rotor core having a laminate of a plurality of annular thin plate-shaped core pieces, the rotor core being configured to rotate together with a shaft in an integrated manner; a cylindrical resin magnet mounted on an outer peripheral surface of the rotor core via a gap; a groove-shaped adhesive admission portion in a straight line along the entire length of the rotor core in an axial direction thereof, the adhesive admission portion being recessed into the outer peripheral surface of the rotor core; and an adhesive configured to bond and fix the rotor core and the magnet. The adhesive is filled in an entire adhesive allowance having both of the gap and the adhesive admission portion between the outer peripheral surface of the rotor core and an inner peripheral surface of the magnet.

First claim

What is claimed is:

1. A rotor applied to an inner rotor brushless motor, comprising:
a rotor core including a laminate of a plurality of annular thin plate-shaped core pieces, the rotor core being configured to rotate together with a shaft in an integrated manner;
a cylindrical resin magnet mounted on an outer peripheral surface of the rotor core via a gap;
a groove-shaped adhesive admission portion in a straight line along the entire length of the rotor core in an axial direction thereof, the adhesive admission portion being recessed into the outer peripheral surface of the rotor core;
an adhesive configured to bond and fix the rotor core and the resin magnet;
a bush fixed to the rotor core and the resin magnet on one end side in the axial direction; and
a sensor magnet fixed to the bush on the one end side, the sensor magnet being configured to rotate together with the shaft in an integrated manner, wherein
the adhesive is filled in an entire adhesive allowance including both of the gap and the adhesive admission portion between the outer peripheral surface of the rotor core and an inner peripheral surface of the resin magnet, and
the bush includes a prevention surface that blocks the gap on the one end side to prevent run-off of the adhesive, and a holding portion that holds the sensor magnet.

2. The rotor according to claim 1 , wherein a plurality of the adhesive admission portions is spaced uniformly in a circumferential direction of the rotor core.

3. The rotor according to claim 1 , wherein the core piece is produced by press blanking, and the thickness of the laminate of the rotor core is equal to or greater than 10 mm and equal to or less than 40 mm.

4. The rotor according to claim 1 , wherein the viscosity of the adhesive is equal to or greater than the viscosity of water and equal to or less than 150 mPa·s.

5. A brushless motor comprising:
a rotor including
a rotor core including a laminate of a plurality of annular thin plate-shaped core pieces, the rotor core being configured to rotate together with a shaft in an integrated manner;
a cylindrical resin magnet mounted on an outer peripheral surface of the rotor core via a gap;
a groove-shaped adhesive admission portion in a straight line along the entire length of the rotor core in an axial direction thereof, the adhesive admission portion being recessed into the outer peripheral surface of the rotor core;
an adhesive configured to bond and fix the rotor core and the resin magnet;
a bush fixed to the rotor core and the resin magnet on one end side in the axial direction; and
a sensor magnet fixed to the bush on the one end side, the sensor magnet being configured to rotate together with the shaft in an integrated manner;

a cylindrical stator including a coil, the stator having, in a center thereof, a space where the rotor is placed;
a shaft configured to rotate together with the rotor in an integrated manner; and
a housing the rotor and the stator, wherein
the adhesive is filled in an entire adhesive allowance including both of the gap and the adhesive admission portion between the outer peripheral surface of the rotor core and an inner peripheral surface of the resin magnet, and
the bush includes a prevention surface that blocks the gap on the one end side to prevent run-off of the adhesive, and a holding portion that holds the sensor magnet.

Assignees

• Mabuchi Motor Co

Inventors

• Shiraki Kenji
• Nishizawa Katsuhito
• Kubota Shou
• Ito Yuhei

Classifications

• H02K1/28 Primary

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

• H02K1/2733 Primary

  Annular magnets · CPC title

• H02K1/2726 Primary

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

• H02K15/03

  having permanent magnets · CPC title

• H02K5/15

  Mounting arrangements for bearing-shields or end plates · CPC title