JPH05276715A - Method of assembling revolving-field type rotor - Google Patents

Abstract

PURPOSE:To prevent the separation of the surface-treated layer of a permanent magnet, which occurs when press-fitting the yoke core fit on a rotary shaft along the inside periphery of the guide piece arranged at the inside periphery of the permanent magnet, in the manufacture process of a brushless motor. CONSTITUTION:Four permanent magnets 15 are so arranged that they form a cylindrical shape as a whole, on the inside surface of a cylindrical cover 17. Guides 16 are arranged, respectively, at the inside surface of these permanent magnets 15. And, the yoke core and the end core 14 incorporated into a rotary shaft 3 are press-fit along the inside surface of the guide 16. At this time, since the yoke core and the end core 14 and the guide only slide on each other, the surface-treated layer of the permanent magnet 15 does not separate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for assembling a rotating field type rotor, and more particularly to a method for assembling a rotating field type rotor in which a permanent magnet is surrounded by a cylindrical cover.

[0002]

2. Description of the Related Art Conventionally, since a brushless motor uses a permanent magnet fitted to a rotating shaft as a rotor, the permanent magnet is scattered or destroyed by centrifugal force caused by high-speed rotation of the motor, or is repeatedly subjected to rapid application. There is a problem that it is easily damaged by deceleration. Therefore, various methods are used to fix the permanent magnets. For example, a method of enclosing the permanent magnets with a cylindrical cover made of stainless steel or the like to prevent the permanent magnets from scattering or breaking is generally adopted. There is.

However, when the rotor is assembled by the above-described method, the rotary shaft is press-fitted or lightly press-fitted along the inner peripheral surface of the permanent magnet arranged on the inner peripheral surface of the cylindrical cover. Due to the sliding contact with the rotating shaft, the inner peripheral surface of the permanent magnet is likely to be scratched. Generally, a neodymium-iron-based magnet as a permanent magnet is subjected to surface treatment for rust prevention, and the scratches impede the rust prevention effect, resulting in a decrease in magnetic characteristics and strength of the permanent magnet. The improvement of the assembling method is desired.

[0004]

In view of the problems of the prior art, the main object of the present invention is to press-fit the yoke core fitted on the rotary shaft of the brushless motor to the inner peripheral side of the permanent magnet. At the same time, it is an object of the present invention to provide a method for assembling a rotating field type rotor in which the inner peripheral surface of the permanent magnet is not scratched.

[0005]

According to the present invention, the above-mentioned object is achieved by stacking annular thin plates to form a cylindrical yoke core, and a plurality of circles surrounding the yoke core so as to form a cylindrical shape as a whole. A method for assembling a rotating field type rotor, wherein an arc-shaped permanent magnet piece and a cylindrical cover surrounding the permanent magnet piece are fitted to a rotating shaft, the permanent magnet being provided on an inner peripheral surface of the cylindrical cover. And a guide formed of a thin plate and having a contour shape substantially the same as the inner peripheral surface of the permanent magnet piece is arranged on the inner peripheral surface of the permanent magnet piece, and the guide piece is fitted to the rotary shaft. It is achieved by providing a method of assembling a rotary field type rotor, characterized in that the yoke core is press-fitted into the inner hole defined by the permanent magnet piece along the inner surface of the guide.

[0006]

According to this structure, the yoke core fitted to the rotary shaft is press-fitted along the inner surface of the guide arranged on the inner peripheral surface of the permanent magnet, so that the surface of the permanent magnet is in sliding contact with any member. Therefore, the surface treatment layer of the permanent magnet does not peel off.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will now be described in detail with reference to the accompanying drawings.

FIG. 1 shows the structure of a brushless motor 1 to which the present invention is applied.
Is an inner rotor type in which a rotor 2 of a rotating field type is arranged inside. The right part of the rotary shaft 3 of the rotor 2 in the drawing is
A ball bearing 5 fixed to a flange 4 to which a load (not shown) is mounted is pivotally supported, and the left side of the figure is a ball bearing 7 fixed to an end bracket 6 as an end plate of the motor 1.
Is pivotally supported by.

A sensor 8 for detecting the rotational position and the rotational speed of the rotor 2 is provided on the left side of the rotary shaft 3 in the figure, on the same axis as the rotary shaft 3 via a coupling 9.

A frame 10 which forms a part of a magnetic path as a cylindrical yoke is sandwiched and fixed between the flange 4 and the end bracket 6. An armature core 11 as a stator is fixed to the inner peripheral surface of the frame 10, and an armature winding 12 as a current line is provided in a slot (not shown) provided in the inner periphery of the armature core 11. Has been paid.

2 to 4 show the internal structure of the rotor 2 in detail. A serration-like groove is formed in the axial direction near the center of the rotary shaft 3, and a yoke core 13 as a yoke formed by stacking annular thin plates in the axial direction is fitted in the groove. At both ends of the yoke core 13 in the axial direction, an end core 14 is formed by stacking several annular thin plates having a diameter slightly smaller than that of the yoke core 13 and having radially outwardly projecting portions 14a.
Is fitted on the rotary shaft 3. A guide 16 is provided between the outer peripheral surfaces of the yoke core 13 and the end core 14 and the inner peripheral surface of a permanent magnet 15 described later. The guide 16 is provided with a flange 16a having substantially the same shape as the longitudinal side surface and one end surface of the permanent magnet 15.

Permanent magnets 15 as field magnets are arranged on the outer peripheral surface of the guide 16. This permanent magnet is composed of four pieces of permanent magnets having a shape obtained by cutting a cylindrical body of a certain length over an angle range of about 80 degrees, and the NS poles formed on the front and back of the permanent magnet alternate. They are arranged with a predetermined gap on a common circumference. A neodymium-iron based magnet is adopted as the permanent magnet 15,
Although this magnet has excellent magnetic properties, it has a drawback that it is easily oxidized, and therefore its surface is subjected to rust prevention treatment. Further, since the permanent magnet 15 is also a heat-molded product, the permanent magnet 15 itself may be destroyed or separated from the guide 16 by the centrifugal force generated by the rotation of the rotor 2. The outer circumference of the magnet 15 is covered with a cylindrical cover 17 made of stainless steel.

Both end portions in the axial direction of the cylindrical cover 17 are sandwiched by side plates 18R and 18L for preventing the magnet from jumping out in the axial direction from the end portion direction. The one side plate 18L also serves as a cover plate for the cylindrical cover 17.

The method of assembling the rotor 2 will be described below. First, the rotor 2 includes the rotary shaft 3 and the yoke core 13.
And an outer portion including a permanent magnet 15, a permanent magnet 15, a guide 16 and a cylindrical cover 17. First, the yoke core 13 and the end core 14 are press-fitted along the groove provided near the center of the rotary shaft 3. Then, in order to improve the coaxial accuracy between the rotary shaft 3 and the outer peripheral surface of the yoke core 13, the inner peripheral portion is formed by grinding the outer peripheral surface of the yoke core 13.

Next, in the outer portion, guides 16 are adhered to the inner peripheral surfaces of the four pieces of permanent magnets 15, respectively, and the four pieces of permanent magnets 15 have a cylindrical cover 17 so as to form a cylindrical shape as a whole. It is formed by adhesion on the inner peripheral surface of the. As a final assembly step, the inner yoke core 13 and the end core 14 are press-fitted along the inner surface of the outer guide 16.
The side plates 18R and 18L are attached to the rotary shaft 3 so as to sandwich the cylindrical cover 13 from both ends in the axial direction of the rotary shaft 3.
Then, the rotor 2 is completed.

As is apparent from the above-mentioned assembly process, when the inner portion is press-fitted into the outer portion, the yoke core 13 and the end core 14 are simply brought into sliding contact with the guide 16, and the surfaces of the four permanent magnets 15 are completely removed. can not be hurt. Further, the protrusion 14a of the end core 14 and the flange 16a on the side surface in the longitudinal direction of the guide 16 are brought into contact with each other, so that the permanent magnet 15 can be prevented from idling due to sudden start or stop of the rotor 2. Further, the flange 16a provided on the guide 16 can prevent the permanent magnet 15 and the guide 16 from being displaced from each other.

Incidentally, if the guide 16 is integrally molded as shown in FIG. 5, the number of parts is reduced, so that the assembly can be easily carried out, and the workability of the assembly is improved and the strength of the guide itself is increased. You can

[0018]

As is apparent from the above description, according to the method for assembling the rotating field type rotor of the present invention, the yoke core fitted on the rotating shaft is disposed on the inner circumference of the permanent magnet piece. Since the permanent magnet piece and the yoke core do not come into direct sliding contact with each other because the permanent magnet piece is press-fitted along the inner circumference, the surface treatment layer of the permanent magnet piece is not damaged. Therefore, it is possible to easily avoid peeling of the surface treatment layer of the permanent magnet without complicating the manufacturing process, and to provide a rotating field type rotor of high quality, which is not much different from the conventional manufacturing cost. You can

[Brief description of drawings]

FIG. 1 is a view showing a brushless motor to which the present invention is applied by being broken along an axis.

FIG. 2 is an exploded perspective view showing a rotor structure to which the present invention is applied.

FIG. 3 is a view showing the rotor structure of FIG. 2 broken along an axis.

FIG. 4 is a sectional view taken along line IV-IV in FIG.

FIG. 5 is a perspective view showing a main part of another example of the present invention.

[Explanation of symbols]

 1 Brushless Motor 2 Rotor 3 Rotating Shaft 4 Flange 5, 7 Ball Bearing 6 End Bracket 8 Sensor 9 Coupling 10 Frame 11 Armature Core 12 Armature Winding 13 Yoke Core 14 End Core 14a Projection 15 Permanent Magnet 16 Guide 16a Flange 17 Cylindrical Cover 18R, 18L Side plate

Claims (1)

[Claims] 1. A yoke core having a cylindrical shape by laminating annular thin plates, a plurality of arc-shaped permanent magnet pieces surrounding the yoke core so as to form a cylindrical shape as a whole, and surrounding the permanent magnet piece. A method of assembling a rotating field type rotor, comprising a cylindrical cover fitted to a rotating shaft, wherein a permanent magnet piece is arranged on an inner peripheral surface of the cylindrical cover, and an inner peripheral surface of the permanent magnet piece. A guide, which is made of a thin plate and has substantially the same contour shape as the inner peripheral surface of the permanent magnet piece, is arranged on the upper side, and the yoke core fitted on the rotating shaft is attached to the permanent magnet along the inner surface of the guide. A method for assembling a rotating field type rotor, characterized by press-fitting into an inner hole defined by a magnet piece.