JPS61128757A - Brushless motor of axial gap type - Google Patents

Abstract

PURPOSE:To prevent uneven rotation from being generated, by providing a plurality of salient sections for the outer peripheral section of a rotor yoke, and by providing a field magnet positioned by the salient sections and a magnet for frequency power generation which is made of synthetic resin for molding some section of the field magnet. CONSTITUTION:A stator 2 fitted on a bearing housing 1 is organized by providing a substrate 4 for a yoke 3 and bonding a field coil 5 on the central section of the substrate 4, and by providing a coil 6 for frequency power generation on the outer peripheral section. And a rotary shaft 7 is supported by the bearing 8 of the housing 1, and a rotor 10 consisting of a rotor yoke 11, a field magnet 12 and a magnet 13 for frequency power generation is fitted on the rotary shaft 7 via a fitting boss 9. Then, the rotor yoke 11 is formed in a disc shape, and a plurality of sections (6 sections) on the outer peripheral section are notched, and the sections are bent to form salient sections 15 of L-form directed outward. The ring-formed field magnet 12 is positioned at the salient sections 15 and is fitted to be molded with the magnet 13 for frequency power generation (synthetic resin including magnetic powder).

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an axial gap type brushless motor in which a field magnet and a frequency power generation magnet are arranged concentrically on a rotor yoke.

[Technical Background of the Invention] Conventionally, in an axial gap type brushless motor, a rotor yoke is drawn into a shallow cylindrical shape, and a rotating shaft is attached to the center of the rotor yoke. The rotor is constructed by gluing field magnets positioned concentrically with the rotor yoke, and gluing a plastic or rubber frequency power generation magnet to the inner peripheral surface of the outer flange of the rotor yoke. . The rotor is disposed facing the stator with a predetermined gap in the axial direction.

[Problems with Background Art] However, the above configuration has the following problems.

(a) Since the rotor yoke is drawn and formed, the inner bottom surface of the rotor yoke is easily deformed, and the flatness of the inner bottom surface cannot be maintained. The gap between the magnet and the stator becomes uneven, which tends to cause uneven rotation.

(b) Since the adhesion position of the field magnet is determined by a jig, there is poor accuracy in the alignment of the field magnet with the rotor yoke and the alignment of the frequency power generation magnet with the rotor yoke and the field magnet. Therefore, the rotor tends to become unbalanced, and it takes a lot of time to adjust the balance.

(C) Frequency power generation magnets made of plastic or rubber have a different thermal expansion coefficient from the rotor yoke, but in the above configuration, the frequency power generation magnet is attached to the rotor yoke with adhesive, so the temperature When this changes, there is a risk that the adhesive will peel off due to the deformation of the frequency power generation magnet, reducing the adhesive strength with the rotor yoke.

[Objective of the Invention 1 The present invention has been made in view of the above circumstances, and its purpose is to prevent the occurrence of uneven rotation, prevent the occurrence of unbalance of the rotor as much as possible, and further improve frequency power generation. An object of the present invention is to provide an axial gap type brushless motor that can ensure adhesive strength between a field magnet, a field magnet, and a rotor yoke.

[Summary of the Invention] The present invention provides a rotor yoke with a plurality of protrusions integrally arranged concentrically with the outer peripheral portion of the rotor yoke, and a field magnet positioned by the plurality of protrusions on the rotor yoke. A frequency power generating magnet made of synthetic resin is provided on the outer periphery of the rotor yoke, and a part of the plurality of protrusions and the field magnet are molded, thereby eliminating the need for drawing and forming the rotor yoke, and providing a field magnet. It is characterized by the ability to ensure alignment between the rotor yoke and the rotor yoke.

A first embodiment of the present invention will be described below with reference to FIGS. 1 and 3. 1 is a bearing housing, to which a stator 2 is attached. This stator 2 consists of a yoke 3 and a substrate 4 attached, and a field coil 5 is attached to the center of the substrate 4.
is adhered, and a frequency power generation coil 6 is formed by printed wiring on the outer periphery. Reference numeral 7 denotes a rotating shaft supported by bearings 8, 8 provided inside the bearing housing 1, and a mounting boss 9 is attached to the upper end of the rotating shaft. 10 is the rotor yoke 11. A rotor consisting of a field magnet 12 and a frequency power generation magnet 13, which includes a rotor yoke 11
A fitting hole 11a formed at the center of the stator 2 is fitted into the center of the mounting boss 9, and is mounted to the mounting boss 9 with a screw 14 so as to face the stator 2 with a predetermined gap. The rotor yoke 11 has a disk shape, and its outer circumference is cut out at a plurality of places, for example, six places, and then bent to form an L-shaped protrusion 15 facing outward. Further, the field magnet 12 has an annular shape, and the outer peripheral surface thereof has a protrusion 15.
The rotor yoke 11 is positioned concentrically with the inner bottom surface of the rotor yoke 11 in contact with the inner surface thereof.

The frequency power generation magnet 13 is made of synthetic resin mixed with magnetic powder, and is molded on the outer periphery of the rotor yoke 11 so as to cover the protrusion 15 and a part of the field magnet 12, such as the outer periphery and side surface. It is attached by.

According to the above embodiment, the following effects can be obtained.

(1) Since the protrusion 15 is provided on the outer periphery of the rotor yoke 11, there is no need for conventional drawing forming to obtain the protrusion 15, and therefore the flatness of the rotor yoke 11 can be maintained reliably. Then, the field magnet 12 and stator 2
The gap between the two is maintained uniformly, and uneven rotation can be prevented.

(2) Since the outer circumferential surface of the field magnet 12 is brought into contact with the inner surface of the protrusion 15, the field magnet 12 is positioned concentrically with the rotor yoke 11 and therefore with the rotating shaft 7, and the rotor 1
The occurrence of zero unbalance can be prevented as much as possible, and the time required to adjust the balance of the rotor 10 can be shortened.

(3) Since the frequency power generation magnet 13 is integrally molded covering the protrusion 15 and part of the outer periphery and side surface of the field magnet 12, unlike conventional adhesive bonding, adhesive There is no problem of peeling, and therefore adhesive strength can be maintained constant regardless of temperature.

FIG. 4 shows a second embodiment of the present invention, in which instead of the integrated field magnet 12, six divided field magnets 16 are arranged evenly around the outer periphery of the rotor yoke 11.
Step portions 17 formed at both ends of the field magnet 16 are arranged in contact with the inner surface of the protrusion 15.

FIG. 5 shows a third embodiment of the present invention, in which a protrusion 15
Instead, a hole 18 is formed in the outer peripheral edge of the rotor yoke 11, and a protrusion 19 as a separate protrusion is integrally fixed therein, for example, by caulking, and the inner part of the protrusion 19 is provided with a hole 18 for the field. The magnet 12 is brought into contact with the magnet 12, and these second and third embodiments have the same effects as the first embodiment.

[Effects of the Invention] As is clear from the above description, the present invention provides a plurality of protrusions on the outer circumference of a rotor yoke, a field magnet positioned by the plurality of protrusions, and a field magnet positioned by the plurality of protrusions. Since the plurality of protrusions and a frequency power generation magnet made of synthetic resin are molded into a part of the field magnet on the outer circumference of the rotor yoke, uneven rotation can be prevented and the imbalance of the rotor can be prevented. This has the effect of being able to prevent this occurrence as much as possible, and also ensuring the adhesive strength between the frequency power generation magnet, the field magnet, and the rotor yoke.

[Brief explanation of drawings]

Figures 1 to 3 show a first embodiment of the present invention, with Figure 1 being a longitudinal sectional side view, Figure 2 being a perspective view of the rotor yoke, and Figure 3 being a perspective view of the field magnet. 4 is a perspective view of a main part showing a second embodiment of the present invention, and FIG. 5 is a longitudinal sectional view of a main part showing a third embodiment of the invention. In the figure, 10 is a rotor, 11 is a rotor yoke, 12 is a field magnet, 13 is a frequency power generation magnet, 15 is a protrusion, 16 is a field magnet, and 19 is a protrusion (indicates a protrusion). Toshiba Corporation W41 Figure n Figure 2 Kaku1a Figure 3

Claims (1)

[Scope of Claims] 1. A disk-shaped rotor yoke, a plurality of protrusions integrally provided on the outer circumferential portion of the rotor yoke, and a plurality of protrusions positioned by the plurality of protrusions. A field magnet provided on the rotor yoke, and a frequency power generation magnet made of synthetic resin provided so as to mold the plurality of protrusions and a part of the field magnet on the outer periphery of the rotor yoke. Axial gap type brushless motor. 2. The axial gap type brushless motor according to claim 1, wherein the protrusion is formed by cutting a portion of the rotor yoke into an outward L-shape.