JPS5863069A - Coreless motor - Google Patents

Abstract

PURPOSE:To increase the effective area of an armature coil and to improve the efficiency of a motor by a method wherein field magnets are positioned at the inside of the armature coil. CONSTITUTION:The first field magnets 14a, 14b and 15a, 15b are fixed to the surface and reverse of a yoke 8 fixed to a bearing pillar 5 so that the magnets may be reverse polarity each other in the shaft direction of a rotor shaft 9. An air core disk-shaped armature coil 11 is provided with free rotation by reserving a gap to the magnetic pole faces of the field magnets so as to surround the field magnets 14a, 14b, 15a, 15b. Furthermore, the second field magnets 16a, 16b and 17a, 17b are provided by holding a coil 11 so that magnetic poles differing from the first field magnets 14a, 14b and 15a, 15b may face each other. In this way, the field magnets can enlarge as far as the position facing to the central section of the coil. Therefore, the part around the center of the coil can utilize for the generation of torque.

Description

[Detailed description of the invention] The present invention relates to a coreless motor.

Various configurations of coreless motors using air-core coils are known, but in all of them, only a portion of the total area of the coil effectively generates torque, and in principle, high efficiency can be achieved. It was impossible. For this reason, a coreless motor constructed to effectively utilize almost the entire area of the coil for torque generation has been proposed in Japanese Patent Application No. 55-18818, and a sectional view of such a coreless motor is shown in FIG.

In Fig. 1, 1 is a case made of magnetic material, 2 is a lid case also made of magnetic material, and 3α and 3b are field magnets formed in a fan shape, magnetized in a direction perpendicular to the surface, and fixed to the inner surface of case 1. Magnets 4α and 4b are field magnets that are also formed in a sector shape, magnetized in a direction perpendicular to the surface, and fixed to the inner surface of the lid case 2, and 5 is a cylindrical non-magnetic material fixed to the center of the lid case 2. 6 and 7 are bearings fixed to both openings of the bearing support 5; 8 is made of a magnetic material and is formed into a disk shape with a center hole; the center hole is located at the tip of the bearing support 5; This is a yoke that is fixed to the bearing support 5 by fitting into it.

On the other hand, 9 is a rotor shaft rotatably supported by bearings 6 and 7, and 10 is an air-centered disk-shaped synthetic resin thin plate arranged along the outer surface of the yoke 8 with a predetermined gap from the outer surface. The coil frame 11 is an armature coil formed by winding a coil wire entirely in the radial direction around the coil frame 10 passing approximately through the center. A center hole 1 is provided in the center of one plane of the coil frame 10 so as not to touch the bearing strut 5.
0α is formed, and the center portion of the other plane serves as a support portion and is fixed to the rotor shaft 9. Therefore, coil 11
The plane part of is held in a plane perpendicular to the rotor axis 9, and rotates within the field space formed between the field magnets 3a, 3b and the yoke 8 and between the field magnets 4α, 4b, respectively. Can be placed freely. Note that 12 is a commutator fixed to the rotor shaft 9, 13α is a positive brush that slides on the commutator 12, and 13b is a negative brush.

In this way, by forming the armature coil in the shape of an air-core disk and rotatably disposing the armature coil so that its plane part is located in the field space; Both flat parts are effective parts that generate torque over almost the entire area, but in this configuration, since the thickness of the central part of the armature coil is much thicker than that of the flat part, the outer side of the coil 11 Positioned field magnet 3α
.

Since 3b, 4α, and 4b cannot be enlarged to positions facing the center of the coil, the portion near the center of the coil cannot be effectively used to generate torque, and there is a limit to the improvement in motor efficiency.

An object of the present invention is to provide a coreless motor that can significantly improve efficiency by reducing the effective area of the armature coil and increasing the magnetic flux interlinking with the coil.

, the coreless motor according to the present invention is provided with an air-centered disk-shaped armature coil that is wound in the radial direction passing near the rotation axis so as to be freely rotatable, and inside this coil, the polarity is reversed in the direction of the rotation axis of the coil. At least two pairs of first field magnets are positioned so that: It is configured with a magnetic magnet.

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 2 is a cross-sectional view showing an embodiment of the present invention, and in the figure, parts equivalent to those in FIG. 1 are indicated by the same reference numerals. In the present invention, the first field magnets 14α, 14b
and 15a, 15bf are fixed to the front and back sides of a yoke 8 made of an iron plate or the like fixed to the bearing column 5 so as to have opposite polarities in the axial direction of the rotor shaft 9, as shown in the figure, and these field magnets 14α, 14b .

15α, 156i, an air-core disk-shaped armature coil 11 is rotatably provided with a gap between the magnetic pole faces of the field magnets, and the first field magnets 14a, 14b, 15α, 15b and a second field magnet so that the different magnetic poles face each other) 16α
, 16b and 17α, 17b, and the rest of the structure is the same as in FIG.

In this way, the field magnets 14α, 14b, 1
5iz.

By locating 15b inside the armature coil 11, the field magnet can be enlarged to a position facing the center of the coil, so that the public money near the center of the coil can also be used for generating torque. Therefore, the flat portion including the center portion of the coil becomes an effective portion that generates torque over the entire area, and the efficiency of the motor can be greatly improved. Furthermore, by providing field magnets that sandwich the coil, the magnetic flux interlinking with the coil can be increased to about twice that of the conventional one, so a large torque can be obtained with a small drive current.

As detailed above (according to the present invention), the effective area of the coil that generates torque can be increased even with a small coil, and the magnetic flux interlinking with the coil can be increased, so the characteristics of the motor are greatly improved. The motor can be downsized to an outer diameter of about 30W.

The coreless motor according to the present invention is suitable for small-sized motors that particularly require high torque, such as spindle motors for video disks and motors for magnetic disk drives.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a conventional example of a coreless motor, and FIG. 2 is a sectional view showing an embodiment of a coreless motor according to the present invention. Explanation of symbols of main parts 5...Bearing strut 8...Yoke 9...
Rotor shaft 11... Armature coil 12...
・Commutator 13α, 13b...Brush 1
4c, 14b, 15a, 15b, 16i,
16b, 17c, 17b-Field Magnenote Applicant Pioneer Co., Ltd. Agent Patent Attorney Itozaimoto Hikoryu/Zuo 2 Figure

Claims (1)

[Claims] An air-core disk-shaped armature coil that is freely rotatable and is wound in the radial direction through the vicinity of the rotation axis; at least two pairs of first field magnets provided so as to have opposite polarities; and at least two pairs of first field magnets provided with magnetic poles different from those of the first field magnets across the armature coil. A coreless motor comprising a second field magnet, a commutator provided at the center of the armature coil, and a brush slidingly in contact with the commutator.