JPH06105505A - Manufacture of magnetic rotor - Google Patents

Abstract

PURPOSE:To improve the quality of a rotor by providing superior sealing of a magnet in a magnetic rotor in which a cylindrical metal tube is fitted around the outer periphery of the magnet. CONSTITUTION:A folded section 5a is previously formed by folding one end of a metal tube 3a to the inside thereof at an acute angle. When the metal tube is fitted around the outer periphery of a magnet, the metal tube 3a is progressively press-fitted around the outer periphery of a magnet 2 from the end of the metal-tube that does not have the folded section 5a. The end of the folded section 5a first comes into contact with the end of a rotor before an angular section of the metal tube comes into contact with the same, and the folded section 5a is deformed in a direction in which the folded section 5a becomes close to a rightangled shape further by press-fitting the metal tube.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotor of an electric motor used in a hermetic compressor, and more particularly to a rotor provided with a permanent magnet field.

[0002]

2. Description of the Related Art A rotor equipped with a magnet for use in a hermetic compressor is intended to reinforce the magnet so that the magnet does not scatter due to centrifugal force and to seal the magnet powder and the like so as not to leak to the outside of the rotor as much as possible. The protective member covers the outer peripheral portion of the rotor and both axial end portions of the rotor.

6 and 7 are sectional views showing the structure of the rotor, which is disclosed in, for example, Japanese Patent Laid-Open No. 2-246748. In this rotor, a plurality of tile-shaped magnets 2 are arranged on the outer peripheral portion of a thick-walled cylindrical yoke iron core 1, a thin metal tube 3 is fitted on the outer peripheral portion of the magnet 2, and the axis of the magnet 2 is End plates 4 and 4 are attached to both ends in the direction.

The yoke core 1 has a shaft hole 6, a clamp pin insertion hole 7, and a protrusion 8 for positioning a magnet, and is generally formed by laminating a large number of circular thin iron plates. In the yoke iron core 1, 11 is a crimping clamp portion for crimping and fixing the thin iron plates to each other.
A punching projection is provided on each thin iron plate at the same time as the press punching, and this projection is fitted into a recess on the back surface of the projection in an adjacent thin iron plate to be laminated in a predetermined thickness in a press die. The configuration of the yoke core 1 is not limited to this, and for example, an iron ingot may be processed or an iron-based sintered material may be used. Magnet 2
Is made of a hard magnetic material such as ferrite, but since it cannot be integrally formed with a cylindrical shape, a plurality of tile-shaped pieces are used, and these are arranged in a substantially equidistant arrangement to form a metal pipe. Three
Secure by tightening.

The metal tube 3 is for reinforcing the centrifugal force and sealing the outer peripheral portion, and is preferably made of a non-magnetic material having excellent tensile strength. Generally, a thin plate such as stainless steel is rolled into a cylindrical shape. Formed and fitted by shrink fit or press fit or a combination of both. The end plates 4 and 4 seal both axial end portions of the magnet 2 and are generally made of metal circular thin plates. The end plates 4 and 4 and the metal tube 3 are clearance-fitted, and the end plates 4 and 4 and the yoke core 1 are fixed to each other by a plurality of clamp pins 9 that axially penetrate through each other. There is. After the metal tube 3 is fitted to the outer peripheral portion of the magnet 2 and the end plates 4 and 4 are further attached,
Bent portions 5 and 5 are formed by bending both axial ends of the metal tube 3 toward the inner diameter side. This reduces the gap between the metal pipe 3 and the end plates 4 and 4 to improve the sealing effect, further prevents axial displacement of the metal pipe, and further, the outer diameter of the end of the metal pipe. The purpose is to prevent warpage to the side and protrusion of burr.

If the metal tube 3 is made of a thick material, the eddy current loss increases and the characteristics of the motor deteriorate. Therefore, it is preferable to use the thinnest possible one. However, since the inner diameter accuracy of the metal tube 3 and the outer diameter accuracy of the magnet 2 have large variations, it is natural that the interference between the two becomes excessive.
In this case, if the metal tube 3 is thin, there is a problem in that when the magnet 2 is pressed into the outer peripheral portion, it buckles and a defective product is produced.

Further, by further bending the bent portion 5 of the metal tube toward the inner diameter side, the sealing effect of the magnet 2 can be enhanced, but since the magnet 2 which is easily broken exists inside the portion to be bent and formed, There is a problem that it cannot be bent with excessive pressure. In order to greatly bend the bent portion 5, it is necessary to form the end plate 4 with a thick material for the purpose of strengthening the support at the time of bending forming and keeping the pressing portion away from the magnet 2. In this case, the rotor is There are drawbacks such as large size and cost increase.

In order to solve the above problem, it is effective to bend and form only one end of the metal tube to the inner diameter side before fitting the metal tube to the outer peripheral portion of the magnet. Filed an application as Japanese Patent Application No. 4-195790. An explanation of this technique is shown in FIG.

In FIG. 8, the metal tube 3b has a bent portion 5b formed by previously bending one end of the cylinder toward the inner diameter side by press molding or the like. By pressing the metal tube 3b from the bent portion 5b side in the direction of the arrow by a press, the metal tube 3b is pressed into the outer peripheral portion of the magnet 2 from the opposite side of the bent portion 5b. At this time, if necessary, the metal tube 3b may be preheated to be shrink-fitted and press-fitted.

The metal tube 3b has a strong waist due to the presence of the bent portion 5b, and therefore buckling or the like due to pressing is less likely to occur. In addition, the bent portion 5 of the metal tube 3b
When forming b, since there is no danger of damaging the magnet 2, it is possible to apply a large amount of pressure to the forming, and it is also possible to arrange the mold inside the metal tube 3b to perform the forming. The feature is that it can be bent greatly toward the inner diameter side.

[0011]

In the method shown in FIG. 8, when the metal tube 3b is press-fitted into the outer peripheral portion of the magnet 2, the bent portion 5b comes into contact with the upper end plate 4 to complete the press-fitting. The state at the end of this press-fitting is shown in the enlarged view of FIG. Since the inner corner 10 of the bent portion 5b of the metal tube 3b has a minimum radius required for bending, the radius of the corner 10 contacts the outer diameter of the end plate 4 so that the bent portion 5b ends. There is a phenomenon that the plate 4 is lifted up. Since the end plate 4 and the metal tube 3b are clearance-fitted, minute gaps exist between them, and in the configuration shown in FIG. 9, the bent portion 5b has a magnet sealing effect. I can't expect. Therefore, there is a drawback that magnet powder or the like easily leaks to the outside of the rotor.

[0012]

According to the present invention, in a magnet rotor constituted by fitting a cylindrical metal tube to an outer peripheral portion of a magnet, one end of the metal tube is previously bent into an inner diameter side at an acute angle. The bent portion is formed in advance, and at the time of the fitting, the metal tube is pressed into the outer peripheral portion of the magnet from the side without the bent portion, and the tip of the bent portion is placed before the corner portion. The rotor is brought into contact with the end portion of the rotor and further press-fitted to deform the bent portion in a direction approaching a right angle.

[0013]

When the bent portion of the metal tube is deformed from the acute angle to a direction approaching a right angle, the tip of this bent portion is in close contact with the rotor end over the entire circumference.

[0014]

Embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an example of a process of fitting a metal pipe in the present invention. The metal tube 3a has a bent portion 5a formed by bending one end of the cylinder toward the inner diameter side in an acute angle by press molding or the like. By pressing the metal tube 3a from the bent portion 5a side in the direction of the arrow by a press, the metal tube 3a is pressed into the outer peripheral portion of the magnet 2 from the side where the bent portion 5a is not provided.

When the metal tube 3a is press-fitted into the outer peripheral portion of the magnet 2, the bent portion 5a is, as shown in FIG.
The bent portion 5a is formed at an angle such that the tip portion 12 comes into contact with the end plate 4 before the rounded portion of the inner corner portion 10 of the bent portion 5a. When the press-fitting is further performed from the state of FIG. 2, as shown in FIG. 3, the bent portion 5a is deformed from the acute angle shape to a direction approaching a right angle, and the elasticity accompanying this deformation causes the tip 12 to move the tip 12 to the end plate 4.
It strongly abuts and sticks to it. The press-fitting step may be terminated if the bent portion 5a is deformed to some extent and the tip portion 12 is in a state of strongly abutting the end plate 4 over the entire circumference,
On the other hand, it is possible to press-fit to a position where the rounded portion of the inner corner 10 of the bent portion 5a comes into contact with the outer diameter of the end plate 4.

As described above, since the bent portion 5a is always in the state where the elastic force is applied, the close contact with the end plate 4 is good and the sealing effect of the magnet 2 can be improved. The corners formed by the axial end surface of the end plate 4 and the outer peripheral surface are rounded or chamfered, or the outer diameter of the end plate 4 is set to the magnet 2.
By making it slightly smaller than the outer diameter of the end plate 4, the close contact of the bent portion 5a with the end plate 4 is further improved. The above characteristics do not change at all when the shape of the end plate is changed as shown in FIG. 4 or when the end plate is not attached as shown in FIG.

The end plate 4a shown in FIG. 4 is formed in a tray shape by providing a portion 13 bent in the axial direction on the outer phantom portion, and the portion on which the pressing force acts is moved away from the magnet 2 and is pressed. This is a structure for preventing the magnet 2 from cracking.

The structure shown in FIG. 5 has a structure in which the end plate is abolished and the end of the magnet 2 is covered by the bent portion 5c of the metal tube 3c. The bent portion 5c is formed to be long toward the inner diameter side, and the inner diameter side end portion is in close contact with the yoke core 1. In this case, the corner 14 formed by the axial end surface of the magnet 2 and the outer peripheral cylindrical surface is rounded or chamfered, or the axial length of the magnet 2 is set shorter than that of the yoke core 1 to bend the magnet 2. The adhesion of the portion 5c to the yoke iron core 1 is further improved. The procedure of fitting the metal tube to the outer peripheral portion of the magnet in the rotor shown in FIGS.
The procedure is the same as that described in.

[0019]

According to the present invention, in a method in which one end of the metal tube is bent and formed in advance toward the inner diameter side before the magnet is fitted to the outer peripheral portion, the bent portion of the metal tube is formed over the entire circumference of the rotor. It is closely contacted with the end portion and the magnet is hermetically sealed so that the magnet powder does not get wet, which greatly contributes to the improvement of the quality of the rotor.

[Brief description of drawings]

FIG. 1 is a front sectional view showing an embodiment of the present invention and showing a step of fitting a metal pipe.

FIG. 2 is an enlarged front cross-sectional view of a main part of the rotor, showing an embodiment of the present invention and showing a state in which the metal pipe is being fitted.

FIG. 3 is an enlarged front cross-sectional view of the essential parts of the rotor, showing an embodiment of the present invention and showing a state after the metal tube is fitted.

FIG. 4 is an enlarged front sectional view of a main part of a rotor showing another embodiment of the present invention.

FIG. 5 is an enlarged front cross-sectional view of a main part of a rotor showing still another embodiment of the present invention.

FIG. 6 is a plan sectional view of a rotor showing a conventional example.

FIG. 7 is a front sectional view of a conventional rotor.

FIG. 8 is a front sectional view showing an example of a conventional step of fitting a metal pipe.

FIG. 9 is an enlarged front sectional view of an essential part of a rotor after fitting a metal tube showing a conventional example.

[Explanation of symbols]

 1 Yoke Iron Core 2 Magnets 3, 3a, 3b, 3c Metal Tube 4, 4a End Plates 5, 5a, 5b, 5c Bending Part 10 Corner of Bending Part 12 Tip of Bending Part

Claims (1)

[Claims] 1. A magnet rotor configured by fitting a cylindrical metal tube to the outer periphery of a magnet, wherein one end of the metal tube is bent and formed inward toward the inner diameter side in advance to form a bent portion. Every time, at the time of fitting, the metal tube is pressed into the outer peripheral portion of the magnet from the side without the bent portion,
A method of manufacturing a magnet rotor, characterized in that the tip of the bent portion is brought into contact with the rotor end portion before the corner portion, and is further pressed to deform the bent portion in a direction approaching a right angle.