JPH01134977U

JPH01134977U -

Info

Publication number: JPH01134977U
Application number: JP3192188U
Authority: JP
Priority date: 1988-03-09
Filing date: 1988-03-09
Publication date: 1989-09-14

Description

[Brief explanation of the drawing]

第１図は本考案の一実施例を示すブラシレスモ
ータの縦断面図、第２図は第１図内Ａ部の部分拡
大図、第３図は第２図内Ｂ―Ｂ部における断面図
、第４図は本考案における速度発電機の平面図、
第５図ａは本考案における速度発電機とメインマ
グネツトの位置関係を示す図、第５図ｂは第５図
ａに示される速度発電機より出力される起電力を
示す図、第６図及び第７図は従来のブラシレスモ
ータの縦断面図、第８図は第６図内Ｃ部の部分拡
大図、第９図は従来例におけるメインマグネツト
とＦＧマグネツトの配置関係を示す図、第１０図
は従来例における速度発電機の平面図である。３…コア、４…コイル、５…ロータヨーク、６
…シヤフト、８…メインマグネツト、９…回転位
置検知素子、１０…ＦＧマグネツト、１１…速度
発電機。 FIG. 1 is a longitudinal sectional view of a brushless motor showing an embodiment of the present invention, FIG. 2 is a partially enlarged view of section A in FIG. 1, and FIG. 3 is a sectional view taken along section BB in FIG. Figure 4 is a plan view of the speed generator according to the present invention.
FIG. 5a is a diagram showing the positional relationship between the speed generator and the main magnet in the present invention, FIG. 5b is a diagram showing the electromotive force output from the speed generator shown in FIG. 5a, and FIG. 7 is a vertical sectional view of a conventional brushless motor, FIG. 8 is a partially enlarged view of section C in FIG. 6, FIG. 9 is a diagram showing the arrangement relationship between the main magnet and FG magnet in the conventional example, FIG. 10 is a plan view of a speed generator in a conventional example. 3...core, 4...coil, 5...rotor yoke, 6
... Shaft, 8... Main magnet, 9... Rotation position detection element, 10... FG magnet, 11... Speed generator.

Claims

[Claims for Utility Model Registration] (1) An annular first magnet that is magnetized to have different polarities alternately in the circumferential direction; , a second magnet disposed concentrically on the outer circumferential side of the first magnet, a rotational position detection element installed to detect the magnetic pole position of the first magnet, and a second magnet disposed concentrically on the outer circumferential side of the first magnet.
a speed generator for detecting the magnetic poles of a magnet, wherein the number of magnetic poles magnetized on the second magnet is different from the number of magnetic poles magnetized on the first magnet. (2) A first magnet that is magnetized so that the entire inner circumferential surface of the annular magnetic body has different polarities alternately in the circumferential direction, and a first magnet that is magnetized to have different polarities alternately in the circumferential direction of the entire inner circumferential surface of the magnetic body; a second magnet magnetized to form a pole;
A rotational position detection element installed on the inner peripheral side of the magnetic body to detect the magnetic pole position of the first magnet, and a speed generator having a correlation with the magnetic pole of the second magnet to detect the magnetic pole of the second magnet. The number of magnetic poles magnetized on the second magnet is an even multiple of the number of magnetic poles magnetized on the first magnet, and the circular arc formed by one magnetic pole magnetized on the first magnet A brushless motor characterized in that an even number of magnetic poles of the second magnet are present within an angle.