| 摘要 |
PURPOSE:To provide a high efficiency brushless motor with which a thrust force can be obtained without producing vibrations and noises. CONSTITUTION:A shaft 5 which is supported in the bottomed supporting cylinder 2 of a housing 1 with a sleeve bearing 3 therebetween so as to rotate freely, a thrust receiver 8 which is provided at a certain position in the supporting cylinder 2 and against which the tip of the shaft 5 is pressed, a bottom-up bowl-shaped rotor 11 which is fixed to the base part of the shaft 5, a stator 14 which is put onto the supporting cylinder 2 and fixed to it and rotor magnets 13 which are fixed to the inner circumference of the rotor 11 so as to face the outer circumference of the stator 14 are provided. The shaft 5 is made of magnetic material. A cylindrical magnet 6 which is magnetized radially is provided inside the supporting cylinder 2 so as to face the outer circumference of the shaft 5. Annular trenches 10a and 19b are formed in the shaft 5 at positions corresponding to the upper inside part and lower inside part of the cylindrical magnet 6. The width of the annular trench 10b of the tip side of the shaft 5 is larger than the width of the annular trench 10a of the base side of the shaft 5. |
