Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
2000-08-30
2002-11-05
Mullins, Burton S. (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S06800R
Reexamination Certificate
active
06476526
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a direct current brushless motor for a fan, especially to a motor in which the position of a sensor is altered a certain distance to obtain a better activation effect.
2. Description of Related Art
With reference to
FIG. 5
, a conventional direct current brushless motor for a fan has a housing (
31
), a stator assembly (
30
) and a rotor assembly. The stator assembly (
30
) is contained in and fixed with respect to the housing (
31
). The rotor assembly is contained in and able to rotate with respect to the housing (
31
). The rotor assembly includes a metal cover (
312
) under the housing (
31
), four magnetic sectors evenly arranged under and along the metal cover (
312
), and a shaft (
311
). Each magnetic. sector is made up of a permanent magnet (
313
). The stator assembly (
30
) consists of four stator poles (
301
) evenly arranged on a round seat, a sleeve (
33
), a circuit board (
32
), and a sensor (
321
) electrically connected to the circuit board (
32
) and fixed between two stators poles (
301
). The round seat covers the sleeve (
33
). The sleeve (
33
) is connected to the shaft (
311
) by a bearing (
34
). The sensor (
321
) is used to sense the magnetic strength of the permanent magnets (
313
) and send signals to the circuit to activate the motor and keep the motor running. Before the motor is activated, the sensor (
321
) always stops with a sensing window (
322
) stopping right above where two neighboring permanent magnets (
313
) meet.
However, this kind of motor has a drawback. The magnetic strength where two neighboring permanent magnets (
313
) meet is the weakest. Therefore, it is always difficult, or needs a large activation current, to activate the motor.
SUMMARY OF THE INVENTION
The main object of the invention is to provide a direct current brushless motor in which the sensing window of the sensor is altered a certain distance to obtain a better activation effect.
REFERENCES:
patent: 3805134 (1974-04-01), Osamu et al.
patent: 4357563 (1982-11-01), Ohno
patent: 4704567 (1987-11-01), Suzuki et al.
patent: 5821744 (1998-10-01), Shinjo et al.
patent: 6097129 (2000-08-01), Furtwaengerl et al.
patent: 6109892 (2000-08-01), Horng
Kamrath Alan
Mullins Burton S.
Rider Bennett Egan & Arundel LLP
LandOfFree
Direct current brushless motor for a fan does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Direct current brushless motor for a fan, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Direct current brushless motor for a fan will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2985740