brushless motor

Abstract

A brushless motor, just by changing the shape of the pole teeth of the stator core, the relative ratio of the pole teeth and the rotor magnetic poles can be hypothetically reduced, so that the cost increase and the assembly workability caused by additional parts will not increase, and the assembly workability can be improved. cogging torque. The stator core (4) is provided with a plurality of first pole teeth (4a1), second pole teeth (4a2), and third pole teeth (4a3) protruding radially outward in the circumferential direction, and the first pole teeth and the rotor magnet (13 ) of any magnetic pole coincidently facing each other, and the tooth top (4a1a) is formed into a symmetrical shape with respect to the radial axis, and the shape of the second pole tooth and the third pole tooth adjacent to the first pole tooth in the circumferential direction is a tooth The crest is formed in an asymmetric shape with respect to the radial axis, and the gap (t2) between the crest of the second pole tooth and the crest of the third pole tooth is larger than that of the crest of the second pole tooth and the tooth crest of the first pole tooth. The gap (t1) between the crests and the gap (t1) between the crests of the third pole teeth and the crests of the first pole teeth are narrow.

Description

technical field [0001] The present invention relates to a brushless motor used for, for example, HVAC (Heating, Ventilation, and Air Conditioning: Heating, Ventilation, and Air Conditioning) equipment and the like. Background technique [0002] For example, refer to image 3 The structure of the stator and the rotor of the external rotor type three-phase DC brushless motor will be described. The structure of the stator 1 will be described. The stator core 4 is a laminated core in which electromagnetic steel sheets are laminated. A plurality of pole teeth 4 a protrude radially outward from the annular core body. A coil (not shown) is wound around each pole tooth 4a. The stator core 4 is press-fitted and bonded to the outer periphery of a bearing housing (not shown) to be assembled. The bearing is embedded in the bearing housing. [0003] The rotor 8 is integrally assembled by caulking a cup-shaped rotor yoke 12 to a rotor hub fixed to one end of the rotor shaft. A ring-...

AI Technical Summary

Problems solved by technology

[0008] However, when an additional iron core is provided in addition to the stator iron core as in Patent Document 1, not only does the number of parts increase, but also an additional iron core other than the stator iron core needs to be attached to the housing, so the motor will be enlarged in the axial direction.

[0009] In addition, due to the additional parts of the motor, the cost may increase and the assembly workability may decrease.

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