JPH05219708A - Brushless motor - Google Patents

Abstract

PURPOSE:To remarkably reduce thickness and size of a brushless motor and improve its axial stiffness and its life time. CONSTITUTION:In a housing 1 including a bearing 3, a shaft 5 whose one end surface is sphere-like, and a thrust plate 8, the bearing 3 is made to have the constitution wherein it is so pressurized as to keep a constant position. Thereby, the thickness and size of a brushless motor can be reduced very much, and its life time and its axial stiffness can be improved largely.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brushless motor composed of one bearing (hereinafter referred to as a motor).

[0002]

2. Description of the Related Art In recent years, motors have been required to be ultra-compact and ultra-thin in accordance with the tendency of weight reduction, size reduction and thickness reduction of sets.

A conventional motor will be described below with reference to FIGS. 5 and 6. As shown in FIG. 5, the motor housing 1b has a cylindrical portion, the stator winding 2 is attached to the outer surface of the cylindrical portion, and the upper bearing 3 and the lower bearing 4 are attached to the inner surface in two stages. A shaft 5b is rotatably attached to the housing 1b via an upper bearing 3 and a lower bearing 4,
A rotor yoke 7b having a rotor magnet 6 is fixed to b. Further, FIG. 6 shows another conventional motor. The same components as those in FIG. 5 are omitted and only different configurations will be described. The housing 1c has a structure having a cylindrical portion for holding the stator winding 2, and a rotor yoke 7 in which a shaft 5c is fixed to the housing 1c and a rotor magnet 6 is fixed via an upper bearing 3 and a lower bearing 4.
It is designed to hold c.

[0004]

However, as shown in FIG.
In the conventional configuration shown in FIG. 6, the bearings are mounted at two positions, upper and lower, and it is necessary to make the structure of the bearing itself smaller and thinner in order to realize ultra-miniaturization and ultra-thinness. However, it has been difficult to obtain the required shaft rigidity due to the downsizing and thinning of the bearing, and the life has also become a problem, which is not suitable for ultra-miniaturization and ultra-thinning.

The present invention is intended to solve the above problems, and it is an object of the present invention to achieve ultra-thinness and ultra-miniaturization as well as a long life and high axial rigidity.

[0006]

In order to achieve the above object, the present invention provides a housing having one bearing, a rotatable shaft having a spherical end surface, and a thrust receiver.
A predetermined position preload is applied to and held on the bearing.

[0007]

According to the present invention, the bearing 1 has the above-mentioned structure.
The motor bearing can be configured in a space for a single piece, a shaft having a spherical end surface, and a space where there is little thrust receiver, and the shaft rigidity can be increased with a simple structure to improve the service life.

[0008]

(Embodiment 1) Hereinafter, a first embodiment of the present invention will be described with reference to FIG. The same members as those in the conventional configuration are designated by the same reference numerals as in the conventional example, and the description thereof is omitted.

As shown in FIG. 1, a motor housing 1
Has a cylindrical portion, and the stator winding 2 is provided on the outer surface of the cylindrical portion.
The bearing 3 is attached to the inner surface, and the thrust plate 8 is held at the corresponding position of the shaft 5 in the central portion. The shaft 5 has a spherical end surface and is held by the thrust plate 8 and the bearing 3. A rotor yoke 7 to which a rotor magnet 6 is attached is fixed to the shaft 5.

(Second Embodiment) A second embodiment of the present invention will be described below with reference to FIG.

As shown in FIG. 2, the housing 1 has a cylindrical portion, the stator winding 2 is attached to the outer surface of the cylindrical portion, the bearing 3 is attached to the inner surface thereof, and the thrust plate 8 is provided at a position corresponding to the shaft 5a in the central portion. Is configured to hold. A rotor yoke 7 having a rotor magnet 6 is fixed to the shaft 5a. The difference from FIG. 1 is that the end surface of the shaft is spherical and the steel ball 9 is fixed to the end surface of the shaft 5a.

(Embodiment 3) A third embodiment of the present invention will be described below with reference to FIG.

As shown in FIG. 3, the housing 1a has a cylindrical portion for holding the stator winding 2, and further has a shaft 5
Is fixed. A rotor magnet 6 and a thrust plate 8 are attached to the rotor yoke 7a, and further the bearing 3 is held.

(Fourth Embodiment) A fourth embodiment of the present invention will be described below with reference to FIG.

As shown in FIG. 4, the housing 1a has a cylindrical portion for holding the stator winding 2, and further the shaft 5
It has a structure in which a is fixed. A rotor magnet 6 and a thrust plate 8 are attached to the rotor yoke 7a,
Further, the structure for holding the bearing 3 is different from FIG. 3 in that the end face of the shaft is spherical and the steel ball 9 is fixed to the end face of the shaft 5a.

The first embodiment, the second embodiment, the third embodiment
In the embodiment and the fourth embodiment, the bearing 3, the shaft 5, and the shaft 5a are individually configured, but it goes without saying that a so-called shaft bearing in which the bearing inner ring and the shaft are paired may be used.

[0017]

As is apparent from the above description of the embodiments, the present invention is a housing having one bearing, a rotatable shaft having a spherical end surface, and a thrust receiver, and a predetermined position preload is applied to the bearing to hold it. By doing so, it is possible to use one bearing having a large size, the life of the bearing is improved, and it is possible to realize an excellent motor capable of increasing the shaft rigidity.

[Brief description of drawings]

FIG. 1 is a sectional view of a motor according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a motor according to a second embodiment of the present invention.

FIG. 3 is a sectional view of a motor according to a third embodiment of the present invention.

FIG. 4 is a sectional view of a motor according to a fourth embodiment of the present invention.

FIG. 5 is a cross-sectional view of a conventional motor

FIG. 6 is a sectional view of another conventional motor.

[Explanation of symbols]

 1,1a Housing 3 Bearing 5,5a Shaft 8 Thrust plate 9 Steel ball

Claims (4)

[Claims] 1. A housing having one bearing, a rotatable shaft having a spherical end surface, and a thrust receiver,
A brushless motor in which a fixed position preload is applied to and held on the bearing. 2. The brushless motor according to claim 1, wherein a steel ball is press-fitted into the end surface of the shaft. 3. A brushless motor having a single bearing, a shaft having a spherical end surface fixed to the housing, and a rotor frame having a thrust receiver, which holds the bearing by applying a predetermined position preload. 4. The brushless motor according to claim 3, wherein a steel ball is press-fitted into the shaft end surface.