JP2005204372A - Motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor having a good space efficiency in which an axial loss torque is reduced, a high efficiency and a miniaturization are achieved. <P>SOLUTION: The motor includes a rotor magnet 1 having an output shaft 1a rotatably supported, yokes 4, 5 for constituting a magnetic circuit with opposed poles at a gap interval to the rotor magnet, and coils 7, 8 for energizing the yokes. The yoke is made of an iron-based oil impregnation magnetic member, and its bore functions as an oil impregnation bearing for rotatably supporting the output shaft of the rotor magnet. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a motor such as a small stepping motor.

  3 and 4 show an example of a conventional motor. A conventional motor has a cylindrical rotor magnet 11 having an output shaft that is magnetized by n poles in the radial direction and is rotatably supported by inner yokes 14 and 15 described later, and sandwiches the rotor magnet 11. Outer yokes 12 and 13 which are stator yokes made of a soft magnetic material opposed to each other in the thrust direction, and inner yokes 14 and 15 which are stator yokes made of a soft magnetic material which rotatably supports the rotor magnet 11. Coils 16 and 17 for exciting the inner yokes 14 and 15 and the outer yokes 12 and 13, coil bobbins 18 and 19 for supporting the coils 16 and 17, a motor cover 20 for supporting the outer yokes 12 and 13, and a mold The bearings 21 and 22 are made of a non-magnetic material such as copper and are fitted to the inner diameters of the inner yokes 14 and 15.

As described in FIGS. 3 and 4 and Patent Document 1 and the like, the conventional motor is provided with a bearing made of a mold or a copper-based nonmagnetic material on the inner diameter of the inner yoke. In addition, as in Patent Document 2 and others, there is a type in which a hole is formed in a stator yoke such as a pure iron material and used as a bearing.
Japanese Unexamined Patent Publication No. 2003-224958 (see FIG. 3, etc.) Japanese Patent Laying-Open No. 2001-37197 (see FIG. 9 etc.)

  However, in the bearings disclosed in FIG. 3 and FIG. 4 and Patent Document 1, the space for the bearing becomes a dead space, compressing the coil winding space, and reducing the excitation force. It had a problem of inhibiting the conversion. Further, as in Patent Document 2, in a case where a hole is made in a stator yoke made of a soft material such as pure iron and this is used as a bearing, the wear resistance and strength are deteriorated, resulting in shaft loss torque (output shaft (Additional torque generated by the sliding friction of the bearing) increases, which is a major factor that hinders downsizing of the motor. In other words, with large motors, the generated torque is high and the shaft loss torque is negligible. However, as the motor becomes more compact, the generated torque decreases drastically, making it impossible to operate with large shaft loss torque and hindering downsizing. It was a factor.

  In order to solve the above-mentioned problem, the invention according to claim 1 comprises a rotor magnet on which an output shaft is rotatably supported, and a magnetic circuit having a magnetic pole facing the rotor magnet across a gap. The motor includes a yoke and a coil that excites the yoke. The yoke is made of an iron-based oil-impregnated magnetic member, and the inner diameter portion of the motor functions as an oil-impregnated bearing that rotatably supports the output shaft of the rotor magnet. Is.

  In the above configuration, the iron-based oil-impregnated bearing, which is a part of the yoke, acts so as to continue to smoothly and smoothly support the rotor magnet.

  The invention according to claim 2 is a cylindrical rotor magnet which is magnetized by a plurality of magnetic poles and is rotatably supported, and a plurality of magnetic poles facing the outer diameter side and the outer gap of the rotor magnet. An outer yoke having a magnetic pole facing the inner gap on the inner diameter side of the rotor magnet, and constituting a magnetic circuit together with the outer yoke, and being wound around the inner yoke, In the motor having a yoke and a coil for exciting the inner yoke, a part of the inner yoke serves as a motor that also serves as a bearing that rotatably supports the output shaft of the rotor magnet.

  In the above configuration, the inner yoke has a bearing function and acts to rotatably support the rotor magnet.

  The invention according to claim 3 is the motor according to claim 2, wherein the inner diameter portion of the inner yoke where the coil is wound also serves as a bearing.

  In the above configuration, the inner diameter portion of the inner yoke around which the coil is wound functions as a bearing, so that the bearing strength is improved.

  The invention according to claim 4 is the motor according to claim 2 or 3, wherein the inner yoke is composed of an iron-based oil-impregnated magnetic member, and the bearing functions as an oil-impregnated bearing.

  In the above configuration, the lubricating oil of the iron-based oil-impregnated bearing acts so as to continue to support the rotor magnet smoothly and freely.

  The invention according to claim 5 is the motor according to claim 2 or 3 in which the inner yoke is coated.

  In the above configuration, the coating portion of the inner yoke acts so as to continue to support the rotor magnet in a freely rotating manner.

  According to the present invention, a dedicated bearing and a useless space for the dedicated bearing can be eliminated, and wear efficiency and strength as a bearing are provided, and a space efficiency with reduced shaft loss torque is good. It is possible to provide a motor that achieves high efficiency and downsizing.

  As shown in the following example.

  1 and 2 are views showing the configuration of a motor according to an embodiment of the present invention. Specifically, FIG. 1 is a sectional view of the motor, and FIG. 2 is an exploded perspective view of the motor of FIG.

  In these figures, reference numeral 1 denotes a cylindrical rotor magnet, which is magnetized to magnetic poles of 2n poles (for example, n = 5; n is a natural number of 2 or more) in the radial direction, and can be freely rotated by inner yokes 4 and 5 described later The output shaft 1a is supported by the motor. Reference numerals 2 and 3 denote outer yokes made of a soft magnetic material, which are opposed to each other in the thrust direction with the rotor magnet 1 interposed therebetween, and face the rotor magnet 1 with an empty wall gap provided in the radial direction of the outer diameter side of the rotor magnet 1. The magnetic circuit has n poles (for example, n = 5) and each of the inner yokes 4 and 5 described later. Reference numerals 4 and 5 denote inner yokes made of a soft magnetic material that is also an iron-based oil-impregnated bearing that rotatably supports the rotor magnet 1. An inner wall gap is provided in the radial direction on the inner diameter side of the rotor magnet 1. The magnetic circuit is configured by having magnetic poles of opposing single poles and being fixed to the outer yokes 2 and 3, respectively. 6 and 7 are coils for exciting the inner yokes 4 and 5 and the outer yokes 2 and 3, and are wound around the inner yokes 4 and 5 by being supported by coil bobbins 8 and 9 described later. 8 and 9 are coil bobbins for supporting the coils 6 and 7, and 10 is a motor cover for supporting the outer yokes 2 and 3.

  In the above configuration, when the coils 6 and 7 are energized, the outer yokes 2 and 3 and the inner yokes 4 and 5 are excited and attracted to the magnetic poles, repelling and attracting the magnetic poles of the rotor magnet 1, The rotor magnet 1 is driven to rotate as the coils 6 and 7 are energized, and a driving force is transmitted from the output shaft 1a to the outside.

  Here, the output shaft 1 a of the rotor magnet 1 is rotatably supported by the inner yokes 4 and 5. In particular, since the output shaft 1a is supported by the inner diameter portions of the inner yokes 4 and 5 around which the coils 6 and 7 are wound, even if a large external stress is applied to the output shaft 1a, the inner yoke 4 , 5 have sufficient strength as a bearing, and the rotor magnet 1 can be rotated while preventing an increase in shaft loss.

  Further, since the inner yokes 4 and 5 are oil-impregnated bearings, the rotor magnet 1 continues to rotate smoothly without scraping the inner yokes 4 and 5 due to the lubricating oil that oozes out. The inner yokes 4 and 5 may not be oil-impregnated bearings but may be lubricated and coated with Teflon (registered trademark), which improves wear resistance and reduces shaft loss. .

  According to the above embodiment, since a part of the yokes 4 and 5 serving as the stator yoke also serves as the bearing of the output shaft 1a of the rotor magnet 1, the dedicated bearing is eliminated and the dedicated bearing is provided. A useless space can be eliminated, and a simple and space-efficient motor can be obtained.

  Further, the inner yokes 4 and 5 are configured to support the rotor magnet 1 with an inner diameter portion wound around the coils 6 and 7, that is, the bearing portion that rotatably supports the rotor magnet 1 is the coil 6. Since the inner yokes 4 and 5 are wound around the inner yokes 4 and 7, the bearing strength is improved and deformation due to stress or frictional wear on the bearings is improved, so that shaft loss torque can be reduced. A simple motor.

  Further, since the inner yokes 4 and 5 are iron-based oil-containing porous magnetic members, they function as oil-containing bearings. Therefore, the lubricating oil of the oil-impregnated bearing acts so as to continue to support the rotor magnet 1 smoothly and smoothly. Further, when the inner yokes 4 and 5 are coated, the coating portion acts so as to keep the rotor magnet 1 rotatably and smoothly supported. From the above, it is possible to obtain a motor that is excellent in wear resistance as a bearing, has reduced shaft loss, and achieves high efficiency and downsizing.

It is a disassembled perspective view of the motor concerning one Example of this invention. It is sectional drawing of the motor concerning one Example of this invention. It is a disassembled perspective view of the conventional motor. Similarly, it is sectional drawing of the conventional motor.

Explanation of symbols

1 Rotor magnet 2,3 Outer yoke 4,5 Inner yoke 6,7 Coil 8,9 Coil bobbin 10 Motor cover

Claims (5)

A rotor magnet on which an output shaft is rotatably supported; a yoke that forms a magnetic circuit having a magnetic pole facing the rotor magnet across a gap; and a coil that excites the yoke;
The yoke is made of an iron-based oil-impregnated magnetic member, and an inner diameter portion of the yoke functions as an oil-impregnated bearing that rotatably supports the output shaft of the rotor magnet. A cylindrical rotor magnet which is magnetized by a plurality of magnetic poles and is rotatably supported, an outer yoke having a plurality of magnetic poles facing the outer diameter side and the outer gap of the rotor magnet, and an inner diameter of the rotor magnet An inner yoke that forms a magnetic circuit together with the outer yoke, and a coil that is wound around the inner yoke and that excites the outer yoke and the inner yoke. In the motor with
A motor, wherein a part of the inner yoke also serves as a bearing that rotatably supports the output shaft of the rotor magnet.   The motor according to claim 2, wherein the inner yoke has an inner diameter portion around which the coil is wound also serving as the bearing.   4. The motor according to claim 2, wherein the inner yoke is made of an iron-based oil-impregnated magnetic member, and the bearing functions as an oil-impregnated bearing. The motor according to claim 2, wherein the inner yoke is coated.

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