Patent ID: 9246365
Filing Date: 2016-01-26
CPC Classification: H02K

Claim Text:
1. A brushless motor comprising: a rotor; and a stator disposed at an outer circumference of the rotor, wherein the rotor comprises: a shaft; a back yoke fixed on the shaft; a permanent magnet disposed at an outer circumference of the back yoke; a magnet holder disposed on at least one end of the permanent magnet in a shaft axis direction; a first resin portion formed at one ends of the back yoke and the permanent magnet in the shaft axis direction, and configured to fix the back yoke and the permanent magnet; and a second resin portion formed at other ends of the back yoke and the permanent magnet in the shaft axis direction, and configured to fix the back yoke and the permanent magnet, a communication hole that communicates one end side and another end side in the shaft axis direction is formed through the back yoke, between the shaft and the back yoke, or in a combination thereof, a third resin portion is formed within the communication hole, the third resin portion is configured to connect with the first resin portion and the second resin portion, and the first resin portion, the second resin portion and the third resin portion are formed integrally, and the magnet holder is configured to regulate the permanent magnet to move in the shaft axis direction and a circumferential direction of the permanent magnet, wherein the magnet holder comprises: a base portion configured to oppose an end face of the permanent magnet; and a plurality of peripheral wall portions, each of which is configured to contact a contacting part of an outer circumferential surface of the permanent magnet located at the one end of the permanent magnet, and extend along a circumferential direction of the permanent magnet, and the base portion comprises: a plurality of outer circumference parts configured to connect to the plurality of peripheral wall portions; an inner circumference part configured to be located closer to the shaft than the plurality of outer circumference parts and surround the shaft; and a beam part configured to connect the plurality of outer circumference parts and the inner circumference part, the beam part being capable of deforming such that the outer circumference parts depart from the inner circumference part.