JPH02223342A - Rotor with permanent magnet and its manufacture - Google Patents

Abstract

PURPOSE:To give circumferential positional precision for permanent magnets and to prevent them from being broken by fitting a squirrel-cage-shaped body made of a non-magnetic material where a plurality of inserting holes to insert permanent magnets after they were positioned are provided in the circumferential direction into the outside circumference of a yoke and by securing this squirrel-cage-shaped body and the permanent magnets inserted into the inserting holes to the outside circumference of the yoke. CONSTITUTION:A squirrel-cage-shaped body 11 where a plurality of inserting holes 11a to insert permanent magnets 3 in position are provided in the circumferential direction is fitted into the outside circumference of a yoke 2. This squirrel-cage-shaped body 11 and the permanent magnets 3 inserted into the above inserting holes 11a are secured to the outside circumference of the yoke 2 with adhesive, etc. The squirrel-cage-shaped body 11 consists of a non-magnetic material such as aluminium, brass, synthetic resin, etc. The inserting holes 11a are formed in the size tightly to fit the permanent magnets 3. Circumferential positional precision can thereby be given so as to install the permanent magnets 3, while they can be protected against breakage.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to a permanent magnet made of a cylindrical yoke made of a magnetic material for a rotating electric machine, and a plurality of permanent magnets forming magnetic poles arranged around the outer circumference of the cylindrical yoke. The present invention relates to a rotor with magnets and a method for manufacturing the same.

[Conventional technology]

A conventional example of a rotor with permanent magnets for a rotating electric machine will be explained based on FIG. 6. In this figure, a plurality of permanent magnets 3 forming magnetic poles are disposed in the circumferential direction on the outer periphery of a cylindrical yoke 2 made of a magnetic material fitted onto a rotating shaft 1. The permanent magnet 3 is formed into a plate shape having an arcuate cross-sectional shape so as to be in close contact with the outer periphery of the yoke 2, and is magnetized alternately in opposite directions in the radial direction for each adjacent magnetic pole. The permanent magnet 3 is positioned on the outer periphery of the yoke 2 with an adhesive or the like after being positioned with circumferential positional accuracy using a positioning jig or the like.

Moreover, in order to fix the permanent magnet 3 to the outer periphery of the yoke 2, in addition to using an adhesive as described above,
As shown in No. 6 (hereinafter referred to as literature), one or two layers of glass fiber impregnated with a thermosetting resin are wound around the outer circumferential surface of a permanent magnet placed on the outer circumference of a yoke and fixed by heating. It is known that this structure can withstand centrifugal force during ultra-high speed rotation.

[Problem to be solved by the invention]

In the structure shown in Fig. 6, it is necessary to prepare a large number of positioning jigs depending on the size of the yoke 2 and the number of magnetic poles, and it is difficult to achieve positional accuracy if positional deviation occurs when fixing with adhesive etc. In particular, when the magnetic pole becomes large and it is necessary to form the magnetic pole with a large number of permanent magnets 3, there is a drawback that a lot of work is required for positioning and fixing. Furthermore, when the rotor is assembled into the stator, if the permanent magnet 3 is hit by its attractive force against a hard object such as a stator core, the permanent magnet 3 made of rare earth, ferrite, etc. may break because the material is brittle. If the permanent magnet 3 is missing, not only will the attraction force be reduced, but fragments will adhere to the iron core, etc., requiring a lot of work to remove them.Furthermore, if the fragments are left in the gap between the rotor and stator, the rotor will be permanently damaged. It had many drawbacks, including the inability to rotate it.

In addition, the above-mentioned document does not show anything about the positioning and loss of the permanent magnet, so it seems that the same drawback exists, and in the structure shown in the document, the winding of glass fiber impregnated with resin is not possible. Long working hours. Regarding centrifugal force at ultra-high rotational speeds, there is a limit to the number of rotations that can be used depending on the tensile strength of the cured resin and glass fiber, as well as the number of turns.

An object of the present invention is to enable a plurality of permanent magnets forming magnetic poles on the outer periphery of a cylindrical yoke to be mounted with a simple structure, to achieve positional accuracy in the circumferential direction and to prevent damage, and to reduce rotation during use based on centrifugal force. To provide a rotor with permanent magnets and a method for manufacturing the same, which can increase the number of permanent magnets and which prevent magnetic force of magnetized permanent magnets made of rare earth elements from becoming magnetized during the manufacturing process of the rotor. It's about doing.

[Means to solve the problem]

A rotor with permanent magnets according to invention 1 is a rotor with permanent magnets in which a plurality of permanent magnets forming magnetic poles are arranged in the circumferential direction on the outer periphery of a cylindrical yoke made of a magnetic material. A cage-shaped body made of a non-magnetic material provided with a plurality of insertion holes circumferentially into which the permanent magnets are positioned and inserted is fitted onto the outer periphery of the yoke, and the permanent magnets are inserted into the cage-shaped body and the insertion holes. and is fixed to the outer periphery of the yoke with adhesive or the like.

A rotor with permanent magnets according to invention 2 is a rotor with permanent magnets in which a plurality of permanent magnets forming magnetic poles are arranged in the circumferential direction on the outer periphery of a cylindrical yoke made of a magnetic material. A cage-shaped body made of a non-magnetic material provided with a plurality of insertion holes in the circumferential direction into which the permanent magnets are positioned and inserted is fitted onto the outer periphery of the yoke, and the thickness of the cage-shaped body is made smaller than the thickness of the permanent magnets. A cylindrical reinforcing ring made of a non-magnetic material is fitted and fixed to the outer side of the cage-shaped body and the permanent magnet inserted into the insertion hole, and the gap between the yoke and the reinforcing ring is The periphery of the permanent magnet is filled with a curable resin.

In the method for manufacturing a rotor with permanent magnets according to the third aspect, a magnetized permanent magnet is arranged on the outer periphery of a cylindrical yoke, and a reinforcing ring surrounding this permanent magnet is shrink-fitted to attach the permanent magnet to the yoke. In a method for manufacturing a rotor with permanent magnets that are fixed to the outer circumference, the outer circumference of the reinforcing ring, which has been heated for shrink fitting, is held by a removable cylindrical holder made of a magnetic material, and this holder is used to The yoke to which the magnetized permanent magnet is temporarily attached is inserted inside the held reinforcing ring, and after the temperature of the reinforcing ring has decreased and the shrink fit is completed, the holder is attached to the reinforcing ring. It is to be removed from the

[Effect]

In invention 1, the cage-like body not only allows permanent magnets to be mounted with high positional accuracy in the circumferential direction without using a positioning jig, but also protects the permanent magnets and prevents them from being damaged.

In invention 2, in addition to the effect of invention 1, the reinforcing ring made of a non-magnetic material such as austenitic stainless steel retains the centrifugal force of the permanent magnet and does not change the magnetic flux distribution. The hardening resin fills gaps caused by dimensional errors in the circumferential direction, axial direction, and radial direction of the permanent magnets, fixes the permanent magnets in the insertion holes of the cage, and prevents the bending that each permanent magnet itself undergoes due to centrifugal force. Prevents the magnet from breaking due to force.

In invention 3, when the reinforcing ring is shrink-fitted, even if the temperature of the permanent magnet exceeds the thermal demagnetization temperature limit due to the heat transferred to the permanent magnet, the yoke inside the permanent magnet and the outside yoke of the reinforcing ring The holder made of magnetic material increases the permeance coefficient of the magnetic circuit, suppresses the decrease in magnetic flux at high temperatures, and allows individual pre-magnetized permanent magnets to be attached to the rotor, eliminating the need for magnetization after the rotor is assembled. do not have.

〔Example〕

FIG. 1 is a developed perspective view of Embodiment 1, FIG. 2 is a perspective view of Embodiment 2, and FIG. 3 is a partial sectional view perpendicular to the axis of FIG.
Fig. 4 is an assembly process diagram of Fig. 2, and Fig. 5 is an assembly process diagram of Embodiment 3.
It is an assembly process diagram. Components with the same reference numerals as in FIG. 6 have roughly the same functions.

In FIG. 1, a cage-shaped body 11 is fitted onto the outer periphery of a cylindrical yoke 2, and a cage-shaped body 11 is provided with a plurality of insertion holes 11a in the circumferential direction into which permanent magnets 3 are positioned and inserted. 11 and the permanent magnet 3 inserted into the insertion hole 11a are fixed to the outer periphery of the yoke 2 with adhesive or the like. Although this figure shows that each magnetic pole is formed by a large number of permanent magnets 3, the present invention is not limited to this. The cage-shaped body 11
The austenitic stainless steel is made of a non-magnetic material such as aluminum or brass synthetic resin, and the insertion hole 11a is formed with a size that allows the permanent magnet 3 to be snugly fitted therein. Further, the outer circumferential surfaces of the cage-like body 11 and the permanent magnet 3 are formed to have substantially the same diameter. Although the yoke 2 is fitted onto the rotating shaft 1, they can also be formed integrally.

According to the first embodiment, the cage-like body 11 not only allows the permanent magnet 3 to be mounted with high positional accuracy in the circumferential direction without using a positioning jig, but also protects the permanent magnet 3 and prevents it from being damaged. You can also do it.

In FIGS. 2 to 4 showing Embodiment 2, a cage-shaped body 21 is provided with a plurality of insertion holes 21a in the circumferential direction for positioning and inserting permanent magnets 3 on the outer periphery of the cylinder, as in FIG. 1. It is fitted onto the outer periphery of the cylindrical yoke 2 by shrink fit or clearance fit. Although this figure shows that each magnetic pole is formed by a large number of permanent magnets 3, the present invention is not limited to this.

The cage-like body 21 is made of austenitic stainless steel, and is made of a non-magnetic material such as aluminum or brass synthetic resin, and the insertion hole 21a is formed with a size that allows the permanent magnet 3 to be snugly fitted therein. In the figure, since the rotor is elongated, cage-like bodies 21 are used on both sides of the central protrusion 2a of the yoke 2.

Different from FIG. 1, in Example 2, the thickness of the cage-shaped body 21 is larger than that of the permanent magnet 3, and the outside is made of a non-magnetic material with high tensile strength, such as austenitic or stainless steel. A reinforcing ring 4 of a shape is fitted and fixed. Shrink fitting is convenient for fixing, but the insertion hole 21 of the cage-shaped body 21
It may be fixed to the yoke 2 with a plurality of non-magnetic screws (not shown) that penetrate through the skeleton part without a, and when the reinforcing ring 4 is shrink-fitted and fixed, the cage-shaped body 21 can also be fixed at the same time. Good too.

A curable resin 5 is filled between the yoke 2 and the reinforcing ring 4 and around the permanent magnet 3. For filling, thermosetting or room temperature curing resin such as epoxy resin is filled by vacuum impregnation method. An injection port 6 for this purpose is provided, for example, on the outer periphery of the end surface of the cage-like body 21, and an injection port 61 is provided on the outer periphery of the adjacent insertion hole 21a. Instead of the injection port 6 or the like, an injection port 62 may be provided in the yoke 2, or a radial hole may be provided in the outer periphery of the reinforcing ring 4 to serve as the injection port 63.

As mentioned above, the cage-like body 21 is thicker than the permanent magnet 3, but this is because the permanent magnet 3 is generally formed by sintering, is hard, and resists grinding (and has dimensional errors. Insertion hole 21a not only in the direction but also in the circumferential direction and the axial direction
A curable resin 5 is used to fill the gaps in the radial direction, circumferential direction, and axial direction.

The effect of this curable resin 5 is to protect each permanent magnet 3 itself from centrifugal force. In other words, when the permanent magnet 3 is in contact with the reinforcing ring 4 at one point, as illustrated in FIG. Prevents magnet breakage. For example, the strength of rare earth magnets is about 14 kg/la'', and bending force due to centrifugal force must be taken into consideration when used at high rotational speeds.

FIG. 5 showing Embodiment 3 shows the reinforcing ring 4 in Embodiment 2.
This is a manufacturing method that is effective when the permanent magnet 3 is fixed by shrink fitting and the permanent magnet 3 is already magnetized before the shrink fitting. Whereas an extremely large magnetizing device is required to magnetize the rotor after assembly, a small magnetizing device is sufficient for magnetizing each permanent magnet.

In the figure, on a yoke 2 having a shaft 1, permanent magnets 3 which are magnetized in advance and are divided into a plurality of parts on the circumference are arranged with or without a cage-shaped body as in the second embodiment. On the other hand, the reinforcing ring 4 made of a non-magnetic material has a diameter of 200 to
It is held by a cylindrical holder 7 (7a, 7b) made of a magnetic material that is heated to 400° C. and tightened with screws 8.

It is preferable that the reinforcing ring 4 and the holder are heated together to the shrink fit temperature, but they may be heated and held separately.

The yoke 2 to which the magnetized permanent magnet 3 is temporarily attached is inserted into the reinforcing ring 4 held by the holder 7 and raised in temperature, and after the temperature has decreased and the shrink fit is completed, the above-mentioned Remove only the holder 7 from the reinforcing ring 4 by removing the screw 8.

The cylindrical holder is not limited to the one shown in the drawings; for example, a cylindrical holder may be separated along one generatrix line or two generatrix lines separated by 180 degrees to provide a pair of flanges in the axial direction.

According to the above manufacturing method, heat is transferred from the reinforcing ring 4 heated during shrink fitting to the permanent magnet 3, and the temperature of the permanent magnet 3 exceeds the thermal demagnetization limit, and the magnetized permanent magnet This prevents the magnetic flux from decreasing.

The reason is that, for example, the shrink fit temperature is 200 to 300°C, and the thermal demagnetization temperature of a permanent magnet is approximately 500°C for NK steel.
For rare earth magnets, the temperature is about 200°C, and for example, for neodymium (atomic symbol: Nd) rare earth magnets, it is about 100°C. In this way, at a shrink fit temperature exceeding the thermal demagnetization temperature,
If only the reinforcing ring 4 is applied to the magnet, the magnetic flux of the magnetized permanent magnet 3 will be thermally demagnetized.

On the other hand, a holder 7 made of a magnetic material is attached to the outer periphery of the reinforcing ring 4.
By attaching the magnetic material holder 7, the permeance coefficient (=magnetic flux density/magnetomotive force) of the magnetic circuit at high temperatures is reduced.
This is larger than when there is no magnetic flux, suppressing the decrease in magnetic flux at high temperatures.

〔Effect of the invention〕

A rotor with permanent magnets according to the first aspect of the present invention is a rotor with permanent magnets, in which a plurality of permanent magnets forming magnetic poles are arranged in the circumferential direction on the outer periphery of a cylindrical yoke made of a magnetic material. A cage-shaped body made of a non-magnetic material having a plurality of insertion holes in the circumferential direction into which the permanent magnets are positioned and inserted is fitted onto the outer periphery of the yoke, and the cage-shaped body and the permanent magnets inserted into the insertion holes are fitted into the outer periphery of the yoke. Since the magnet is fixed to the outer periphery of the yoke with adhesive, etc., the permanent magnet has a simple structure and can achieve positional accuracy in the circumferential direction without using a positioning jig, and the rotational speed does not move. It also has the effect of being able to be installed in a way that prevents damage.

Invention 2 is a rotor with permanent magnets, in which a plurality of permanent magnets forming magnetic poles are arranged in the circumferential direction on the outer periphery of a cylindrical yoke made of a magnetic material, and the permanent magnets are arranged on the outer periphery of the cylinder. A cage-shaped body made of a non-magnetic material having a plurality of insertion holes provided in the circumferential direction for positioning and insertion is fitted onto the outer periphery of the yoke, the thickness of the cage-shaped body is made larger than the thickness of the permanent magnet, and this A cylindrical reinforcing ring made of a non-magnetic material is fitted and fixed to the outside of the cage-like body and the permanent magnet inserted into the insertion hole, and the permanent magnet is fixed between the yoke and the reinforcing ring. Since the periphery is filled with hardening resin, in addition to the effect of invention 1, the centrifugal force of the permanent magnet is held by the reinforcing ring, and the centrifugal force of each permanent magnet itself caused by shape and size errors of the permanent magnet is reduced. The bending force caused by this is borne by the curable resin, which has the effect of being able to withstand use at ultra-high rotational speeds.

The manufacturing method of invention 3 is a permanent magnet in which a magnetized permanent magnet is arranged on the outer periphery of a cylindrical yoke, and a reinforcing ring surrounding the permanent magnet is shrink-fitted to fix the permanent magnet to the outer periphery of the yoke. In the method for manufacturing a rotor with a rotor, the outer periphery of the reinforcing ring whose temperature has been raised for shrink fitting is held by a removable cylindrical holder made of a magnetic material, and the reinforcing ring held by the holder is The yoke to which the magnetized permanent magnet is temporarily attached is inserted inside the reinforcing ring, and the holder is removed from the reinforcing ring after the temperature of the reinforcing ring has decreased and shrink fitting is completed. , When the shrink fit temperature exceeds the demagnetization temperature of magnets such as rare earth magnets, the configuration of a magnetic circuit with a large permeance coefficient has the effect of suppressing the decrease in magnetic flux and making the rotor smaller. Since each permanent magnet is magnetized in advance, the magnetizing device can be made smaller.

[Brief explanation of the drawing]

FIG. 1 is a developed perspective view of Embodiment 1, FIG. 2 is a perspective view of Embodiment 2, and FIG. 3 is a partial sectional view perpendicular to the axis of FIG.
Fig. 4 is an assembly process diagram of Fig. 2, and Fig. 5 is an assembly process diagram of Embodiment 3.
FIG. 6 is a perspective view of a conventional example. 2... Yoke, 3... Permanent magnet, 4... Reinforcement ring, 5
... Curing resin, 6.61.62.63 ... Inlet, 7a. 7b...Holder, 11.21...Cage-shaped body, 11a
. Figure 1 Figure 2 Figure 351 Figure

Claims (1)

[Scope of Claims] 1) A rotor with permanent magnets in which a plurality of permanent magnets forming magnetic poles are arranged in the circumferential direction on the outer periphery of a cylindrical yoke made of a magnetic material, wherein the permanent magnets are arranged on the outer periphery of the cylinder. A cage-shaped body made of a non-magnetic material having a plurality of insertion holes circumferentially provided for positioning and inserting magnets is fitted onto the outer periphery of the yoke, and this cage-shaped body and the permanent magnet inserted into the insertion hole are connected. A rotor with permanent magnets, characterized in that the rotor is fixed to the outer periphery of the yoke with an adhesive or the like. 2) In a rotor with permanent magnets, which includes a plurality of permanent magnets arranged circumferentially to form magnetic poles on the outer periphery of a cylindrical yoke made of a magnetic material, the permanent magnets are positioned and inserted on the outer periphery of the cylinder. A cage-shaped body made of a non-magnetic material with a plurality of insertion holes provided in the circumferential direction is fitted onto the outer periphery of the yoke, and the thickness of the cage-shaped body is made larger than the thickness of the permanent magnet. A cylindrical reinforcing ring made of a non-magnetic material is fitted and fixed to the outside of the permanent magnet inserted into the insertion hole, and a hardening material is attached around the permanent magnet between the yoke and the reinforcing ring. A rotor with a permanent magnet characterized by being filled with resin. 3) Place a magnetized permanent magnet around the outer circumference of the cylindrical yoke,
In a method for manufacturing a rotor with a permanent magnet, in which a reinforcing ring surrounding the permanent magnet is shrink-fitted to fix the permanent magnet to the outer periphery of the yoke, the outer periphery of the reinforcing ring, which has been heated to a temperature for shrink-fitting, is The reinforcing ring is held by a removable cylindrical holder made of magnetic material, and the yoke to which the magnetized permanent magnet is temporarily attached is inserted inside the reinforcing ring held by the holder, and the reinforcing ring is A method for manufacturing a rotor with permanent magnets, characterized in that the retainer is removed from the reinforcing ring after the temperature of the retainer has decreased and shrink fitting has been completed.