JPH05276716A - 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 cylindrical cover along the inside surface of the guide piece surrounding permanent magnet, in the manufacture process of a brushless motor. CONSTITUTION:Four permanent magnets 15 are arranged on the outside surface of the yoke core and the end core 14 incorporated on a rotary shaft 3. Guides 16 are arranged, respectively, on the outside surface of these permanent magnets 15. And, a cylindrical cover 17 is set and press-fit along the outside surface of the guide 16. At this time, since the guide 16 and the cylindrical cover 17 only slide on each other, the surface-treated layer of the permanent magnet 15 does not exfoliate.

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 preventing the permanent magnets from scattering and breaking by enclosing the permanent magnet with a cylindrical cover made of stainless steel or the like is generally adopted. Has been done.

However, when the rotor is assembled by the above-described method, the cylindrical cover is press-fitted or slightly press-fitted along the outer peripheral surface of the permanent magnet fitted to the rotating shaft, so that the permanent magnet and the cylindrical cover are slid. The contact easily causes scratches on the outer peripheral surface of the permanent magnet. 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 provide a cylindrical cover along the outer peripheral surface of a permanent magnet fitted to the rotating shaft of a brushless motor. It is an object of the present invention to provide a method for assembling a rotating field type rotor, in which the outer peripheral surface of the permanent magnet is not damaged when it is press-fitted.

[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 that surrounds the permanent magnet piece are fitted to a rotating shaft, the permanent magnet piece being provided on an outer peripheral surface of the yoke core. And a guide having a contour shape substantially the same as the outer peripheral surface of the permanent magnet piece is arranged on the outer peripheral surface of the permanent magnet piece, and the cylindrical cover is fitted to the yoke core. The present invention is achieved by providing a method for assembling a rotary field type rotor, characterized in that the permanent magnet piece is fitted and press-fitted along the outer peripheral surface of the guide that surrounds the permanent magnet piece. To be done.

[0006]

According to this structure, since the cylindrical cover is fitted and press-fitted along the outer peripheral surface of the guide fitted to the permanent magnet, the surface of the permanent magnet does not come into sliding contact with any member. The surface treatment layer of the 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-shaped 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 thin-walled cylindrical steel plates in the axial direction is fitted in the groove portion. ing. At both ends of the yoke core 13 in the axial direction, an end core 14 formed by stacking several thin-walled cylindrical steel plates in the axial direction having a diameter slightly smaller than that of the yoke core 13 and having radially outwardly projecting portions 14a is formed. It is fitted on the rotary shaft 3.

The permanent magnet 15 as a field magnet is composed of four pieces of permanent magnets each having a shape in which a cylindrical body of a certain length is cut out over an angle range of about 80 degrees, and NS formed on the front and back sides thereof. The yoke core 13 and the end core 14 are arranged so that the poles alternate with each other so as to have a predetermined gap between the adjacent permanent magnets 15. This permanent magnet 15
Has adopted a neodymium-iron magnet, but this magnet has excellent magnetic characteristics, but has a drawback that it is easily oxidized, and therefore its surface is subjected to rust prevention treatment.

The outer peripheral surface of the permanent magnet 15 is covered with a guide 16 made of a thin plate. The longitudinal side surface and the one end surface of the guide 16 have substantially the same shape as the longitudinal side surface and the one end surface of the permanent magnet 15.
a is provided. The permanent magnet 15 is a sintered molded product, and the permanent magnet 15 is generated by centrifugal force generated by the rotation of the rotor 2.
The guide 16 is covered with a cylindrical cover 17 made of stainless steel so as to prevent them from breaking or detaching from the end core 14.

Both end portions of the cylindrical cover 17 in the axial direction 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 yoke core 13 and the end core 14 are press-fitted along the groove provided near the center of the rotary shaft 3. Here, in order to improve the coaxial accuracy between the rotary shaft 3 and the outer peripheral surface of the yoke core 13, the outer peripheral surface of the yoke core 13 is ground. Next, the guides 16 are adhered to the outer peripheral surfaces of the four pieces of permanent magnets 15, respectively. Then, on the outer peripheral surfaces of the yoke core 13 and the end core 14, the permanent magnet 15 is arranged and bonded and fixed at a position where the flange 16a of the end face in the longitudinal direction of the guide 16 contacts the protrusion 14a. In the process so far,
The inner portion of the rotor 2 is formed.

Next, the cylindrical cover 17 as the outer portion of the rotor 2 is fitted and press-fitted into the inner portion. That is, the cylindrical cover 17 is fitted and press-fitted along the outer peripheral surface of the guide 16. Finally, the side plates 18R, 18L
Is fitted to the rotary shaft 3 so as to sandwich the cylindrical cover 17 from both ends in the axial direction of the rotary shaft 3, and the rotor 2 is completed.

As is apparent from the above-described assembly process, when the outer portion is fitted and press-fitted into the inner portion, the outer peripheral surface of the guide 16 and the inner peripheral surface of the cylindrical cover 17 are slidably brought into contact with each other.
The surface of one permanent magnet 15 is not damaged at all. Further, the protrusions 14a provided on the four sides of the end core 14 and the flange 16a on the end face in the longitudinal direction of the guide 16 are brought into contact with each other to prevent idling of the permanent magnet 15 due to sudden start and stop of the rotor 2. it can. Moreover, the permanent magnet 15 and the guide 16 are provided by the flange 16 a provided on the guide 16.
And can be prevented from shifting from each other.

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

[0019]

As is apparent from the above description, according to the method for assembling the rotating field type rotor of the present invention, the cylindrical cover is fitted along the outer peripheral surface of the guide arranged on the outer periphery of the permanent magnet piece. Since the permanent magnet piece and the cylindrical cover do not come into direct sliding contact with each other because they are press-fitted, 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 cylindrical cover and a method for assembling a rotating field type rotor fitted to a rotating shaft, wherein the permanent magnet pieces are arranged on an outer peripheral surface of the yoke core,
A guide, which is made of a thin plate and has substantially the same contour shape as the outer peripheral surface of the permanent magnet piece, is arranged on the outer peripheral surface of the permanent magnet piece, and the cylindrical cover is fitted to the permanent magnet piece. A method for assembling a rotating field type rotor, characterized in that the permanent magnet piece is fitted and press-fitted along the outer peripheral surface of the guide that surrounds the permanent magnet piece.