Brushless motor and method of manufacturing the same
AssigneePanasonic Corporation
InventorsKoji Kuyama, Kumio Masuda, Kinjiro Okinaga
Life of this patent
Estimating the term…
Abstract
Fluid bearing mechanisms (6a and 6b) are formed between a shaft (2) and a central part (21) of an oil impregnated sintered sleeve (13). The oil impregnated sintered sleeve (13) has such an inner surface formed to be larger in aperture ratio at a thrust support end (23) and a loading end (22) than at a central part (21). With this configuration, it is possible to achieve a brushless motor which can suppress an increase in bearing loss while obtaining necessary bearing stiffness at high rpm.
Claims10
A brushless motor comprising:
- a bracket,
- a shaft having a thrust support end and a loading end, the thrust support end connected to said bracket;
- and
- an oil impregnated sintered sleeve for radially supporting said shaft, said oil impregnated sintered sleeve having an inner surface larger in aperture ratio at the thrust support end and the loading end than at a central part of the oil impregnated sintered sleeve,
- wherein a gap between the shaft and oil impregnated sintered sleeve is for retaining a fluid,
- the shaft comprises a dynamic pressure generating groove on a surface facing the central part of the oil impregnated sintered sleeve, and
- the brushless motor further comprises a magnet connected to the shaft and a stator connected to the bracket for rotationally driving the motor.
A brushless motor, comprising:
- a shaft having a thrust support end, a loading end, and at least one dynamic pressure generating groove in a surface of the shaft;
- an oil impregnated sintered sleeve for supporting the shaft in a radial direction, said oil impregnated sintered sleeve having rough parts with a large aperture ratio on an inner surface at the loading end of the shaft and the thrust support end of the shaft, and having a dense part with a small aperture ratio on an inner surface between the rough parts, said dense part facing said dynamic pressure generating groove of the shaft;
- a cylindrical bearing housing for supporting the oil impregnated sintered sleeve in a radial direction;
- a turntable mounted to said loading end of the shaft for holding a disk;
- a frame fixed to said shaft;
- a cylindrical rotor magnet fixed to an inner surface of the frame;
- a bracket having a holding portion for holding said cylindrical bearing housing;
- and
- a stator facing the rotor magnet and having a conductor wound via an insulator, said stator being connected to said cylindrical bearing housing and fixed with respect to said bracket.
An dynamic pressure oil bearing in which support is provided in a radial direction, via an oil impregnated sintered sleeve, from a vicinity of a thrust support end of a shaft to a vicinity of a loading end of the shaft where a driven target is attached, a motor is rotationally driven by electromagnetic attraction and repulsion between a stator and a magnet of a rotor connected to the shaft, arid a fluid bearing mechanism is formed between the shaft and the oil impregnated sintered sleeve, wherein
- the fluid bearing mechanism is formed between the oil impregnated sintered sleeve and the shaft at central part in axial direction, and
- the oil impregnated sintered sleeve has an inner surface formed to be larger in aperture ratio at the thrust support end and the loading end than at the central part of the oil impregnated sintered sleeve.
Dependencies are inferred from the claim text.