JP2002010549A - Rotor of electric motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the manufacturability by minimizing the time for assembling ferromagnetic materials. SOLUTION: By providing the ferromagnetic materials 16 capable of constituting a plurality of magnetic poles at the protruding parts 17 and by arranging a plurality of the ferromagnetic materials 16 on the surrounding part of the stator side of a frame 11, the number of the ferromagnetic materials 16 to be used is reduced, which consequently enables the time for assembling them to be cut.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor rotor having a magnetic pole made of a ferromagnetic material.

[0002]

2. Description of the Related Art Conventionally, for example, a rotor disclosed in Japanese Patent Application Laid-Open No. H10-94203 is provided as a rotor of a motor having a magnetic pole made of a ferromagnetic material. FIGS. 14 and 15 show the same, and the magnet member 1 made of a ferromagnetic material, for example, ferrite, is arranged on the inner periphery of the frame 2 by the number of magnetic poles. A ring member 3 is arranged on the outer periphery of the frame 2. The outer periphery and the upper part of the ring member 3, between the ring member 3 and the frame 2, between the frame 2 and each magnet member 1, and between the ring member 3 and the magnet member 1. The resin 4 is injected and molded between the respective members, and the magnet member 1, the frame 2, and the ring member 3 are integrated.

[0003] Incidentally, this is an outer rotor type electric motor in which the rotor is positioned outside the stator and rotates.
3 shows the structure of a rotor. In this case, the magnet member 1 is finally magnetized.

[0004]

In the case of the above-mentioned conventional device, a large number (the number of magnetic poles) of the magnet member 1, that is, the ferromagnetic material, is arranged on the inner periphery of the frame 2 in relation to one magnetic pole. Therefore, there is a problem that it takes time to assemble the many magnet members 1. SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a rotor for an electric motor capable of improving the manufacturability without assembling a ferromagnetic material.

[0005]

In order to achieve the above object, a rotor of a motor according to the present invention comprises a ferromagnetic material capable of forming a plurality of magnetic poles, and the ferromagnetic material is provided around a stator side of a frame. The invention is characterized in that a plurality of parts are arranged in a part (the invention of claim 1). According to this, since a single ferromagnetic material can constitute a plurality of magnetic poles, the number of ferromagnetic materials used is reduced, and the ferromagnetic material can be assembled without much trouble.

In this case, the ferromagnetic material preferably has polar anisotropy (the second aspect of the present invention). In this device, the magnetic force of the magnetic pole can be increased as compared with a ferromagnetic material having isotropic or other anisotropy, and accordingly, the motor characteristics can be improved and the ferromagnetic material can be improved. And the thickness of the frame can be reduced.

[0007] The shape of the ferromagnetic material on the stator side is preferably such that it becomes more convex toward the center of the magnetic pole. In this case, the length of the gap between the magnetic pole and the stator is the smallest at the center of the magnetic pole, and is large at both sides. As a result, the magnetic resistance in the gap is also the smallest at the center of the magnetic pole, and large on both sides. As a result, the magnetic flux density in the gap approaches a sine wave in the waveform, and the spatial harmonics are reduced. , Torque ripple is reduced, and vibration and noise are reduced.

Further, the ferromagnetic material is preferably fixed to the frame by a holder for pressing the ferromagnetic material toward the frame (the invention of claim 4). In this device, the ferromagnetic material can be easily and effectively fixed to the frame, and the ferromagnetic material can be easily disassembled and removed from the frame by removing the holder, thereby improving the separability and recyclability of disposal. Is possible.

Further, the holder is preferably provided at a joint portion between the ferromagnetic materials (claim 5). In this device, the ferromagnetic materials can be fixed to each other by the holder in addition to the fixing of the ferromagnetic materials to the frame, and the fixing strength of the ferromagnetic materials can be increased accordingly.

In addition, the ferromagnetic material may have a fixing portion fixed to the frame (the invention of claim 6). Even with this, the fixing strength of the ferromagnetic material to the frame can be increased.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention applied to a rotor of an outer rotor type electric motor will be described below with reference to FIGS. First, FIGS. 1 and 2
Shows a frame 11, and this frame 11 is
It is formed in the shape of a flat so-called cylindrical cup with a bottom by pressing a magnetic material, for example, a steel plate, and has a shaft support mounting hole 12 in the center. Also, this frame 1
1 has an annular portion 13 around the periphery thereof.
A large number of ventilation holes 14 are radially provided at an intermediate portion between the shaft 3 and the shaft support mounting hole 12, and a stepped portion 1 is provided near the annular portion 13.
Five.

On the other hand, the ferromagnetic body 16 is made of a magnetic resin in this case. The magnetic resin is a mixture of a plastic as a binder and a magnetic powder, and forms the ferromagnetic body 16 with the magnetic resin. In this case, the molding method is, for example, an injection molding method, and the molding shape of the ferromagnetic body 16 is an arc shape obtained by equally dividing one ring, and a plurality of (for example, 5
) Convex portions 17. The convex portion 17 becomes a magnetic pole when magnetized later, and has a convex shape toward the center, for example, a cylindrical surface.

In this case, the ferromagnetic body 16 is made anisotropic by forming a magnetic field orientation in which the magnetic direction becomes a predetermined direction at the time of molding. As shown by an arrow A in FIG. 3, polar anisotropy is imparted by performing a magnetic anisotropic orientation in the ferromagnetic material 16 that allows magnetic permeability only between magnetic poles.

In this structure, a plurality of ferromagnetic bodies 16 are arranged on the entire inner periphery of the annular portion 13 of the frame 11 with the respective convex portions 17 being on the inside. 13 is fixed to the inner peripheral surface. In addition,
The rotor of the present embodiment is positioned outside the stator (not shown) and rotates. Therefore, the inside of the annular portion 13 of the frame 11 on which the ferromagnetic material 16 is arranged is the stator side. . Thereafter, the ferromagnetic material 16 is magnetized in a direction that matches the above-described polar anisotropy, thereby increasing the polar anisotropy of the ferromagnetic material 16 and causing each of the projections 17 to have strong strength. It is made up of magnetic poles.

A shaft support 18 is mounted on the shaft support mounting hole 12 of the frame 11. This shaft support 18
Is provided for supporting and attaching a shaft (rotating shaft) (not shown). As shown in FIG. 4, for example, a hexagonal non-circular portion 20 is provided on the outer periphery of a cylindrical tube portion 19 through which the shaft passes. Further, a flange portion 21 as an attachment portion is provided on the outer periphery of the non-circular portion 20, and a plurality of attachment holes 22 are formed in the flange portion 21.

On the other hand, the shaft support mounting hole 12 of the frame 11 is formed in the same non-circular shape as the non-circular portion 20, as shown in FIG. The flange portion 21 is fixed to the peripheral portion thereof by, for example, a screw 23 that passes through each of the mounting holes 22. In this case, the fixing of the shaft support mounting hole 12 to the frame 11 may be performed by other fixing means, for example, caulking a rivet, instead of the screw 22.

As described above, the present structure has the ferromagnetic material 16 capable of forming a plurality of magnetic poles, and a plurality of the ferromagnetic materials 16 are arranged around the stator side of the frame 11. According to the ferromagnetic material 16, a plurality of magnetic poles can be constituted by one. Therefore, as compared with a conventional magnetic pole using one ferromagnetic material for each magnetic pole, the ferromagnetic material 16 can be used. Since the total number of the ferromagnetic bodies 16 can be reduced, the assembling of the ferromagnetic body 16 can be performed without much trouble, and the manufacturability can be improved.

The ferromagnetic material 16 has polar anisotropy, whereby the ferromagnetic material has another anisotropy such as isotropic, axial anisotropy, and radial anisotropy. As compared with the above, the magnetic force of the magnetic pole can be increased, the motor characteristics can be improved accordingly, and the thickness of the ferromagnetic body 16 can be reduced,
Furthermore, the thickness of the frame 11 made of a magnetic material can be reduced, so that the weight can be reduced. In this case, the frame 11 can be eliminated.

Further, the shape of the ferromagnetic body 16 on the stator side is as follows:
The center of the magnetic pole has a convex shape, so that the length of the gap between the magnetic pole and the stator is the smallest at the center of the magnetic pole and is large at both sides. As a result, the magnetic resistance in the gap is also the smallest at the center of the magnetic pole and is large at both sides. As a result, the magnetic flux density in the gap becomes closer to a sine wave in the waveform, and the space harmonics are less. Therefore, the torque ripple is reduced and it is possible to rotate smoothly, cogging, vibration,
Noise can be reduced.

In addition, in the present structure, the ferromagnetic material 16 is formed of a magnetic resin, and the magnetic force can be adjusted by adjusting the grade and the amount of the magnetic powder to improve the motor characteristics. , Countermeasures against cogging, low vibration and low noise. Also, compared to ferrite or magnetic rubber, it is possible to easily form an irregular and complicated ferromagnetic body 16 which can form a plurality of magnetic poles, and further, when assembled to the frame 11, cracks or chips like ferrite. Can be prevented from occurring.

For mounting the shaft support 18, the non-circular portion 20 is fitted into the shaft support mounting hole 12 of the frame 11, which is formed in the same non-circular shape, to prevent rotation.
Then, the flange portion 21 is fixed to the frame 11 by screws 23 or rivets. Thereby, sufficient strength can be obtained for the connection of the shaft support 18 to the frame 11, the accuracy of the shaft center can be improved, and they can be disassembled. , The recyclability can be improved.

5 to 7 show a second embodiment of the present invention. The same parts as those in the first embodiment are denoted by the same reference numerals, and their description will be omitted. Only the part will be described. In this case, instead of the above-described bonding, the ferromagnetic body 16 is replaced with a holder 31 that presses the ferromagnetic body 16 against the frame 11.
To the frame 11.

As shown in detail in FIG. 6, the holder 31 has a claw 33 on one side edge (left side in the figure) of the substrate 32.
An upright portion 34 is erected on the other side edge (right side in the figure), and further,
The upright portion 34 has a claw 35 at an upper end thereof, and is entirely made of, for example, plastic. In this case, in particular, the upright portion 34 is formed in a substantially triangular prism shape that matches the shape of the concave portion between the convex portions 17 of the ferromagnetic body 16. On the other hand, in the frame 11, as shown in FIG. 7, a flange 36 is formed at the leading edge of the annular portion 13, and a holder mounting hole 37 is formed in the step 15.

In this configuration, the ferromagnetic material 16 arranged on the inner periphery of the annular portion 13 of the frame 11 is
And, by the upright portion 34, it is pressed toward the step portion 15 and the annular portion 13 side (the frame 11 side), and in this state, the claw 33 is engaged with the collar portion 36 of the frame 11. Further, the pawl 35 is pressed into the holder mounting hole 37 to be engaged. In this case, as shown in FIG. 5, the holder 31 is provided at a joint portion between the ferromagnetic bodies 16 and straddles between the ends of two ferromagnetic bodies 16 adjacent to each other at the joint portion. .

Thus, the ferromagnetic material 16 is fixed to the frame 11 by the holder 31. By doing so, the ferromagnetic material 16 can be easily fixed to the frame 11 as compared with the above-mentioned bonding or the like. . In particular, the conventional structure in which the frame 2 and the magnet member 1 are integrated with the resin 4 cannot be easily achieved, and the equipment cost such as the cost of the mold for molding the resin 4, the cost of the mold maintenance, and the like. However, it was not possible to easily change and reduce the size of the ferromagnetic material 16 to the frame 11 by the holder 31. They can also solve those problems.

Further, in this case, the holder 31 is located on the side of the stator of the ferromagnetic body 16 and functions to hold the ferromagnetic body 16 on the side of the frame 11 against the magnetic force of the stator. Ferromagnetic material 1 for frame 11
6 can be fixed effectively.

In addition, in this case, the holder 31 is more difficult to disassemble because the frame 2 and the magnet member 1 cannot be easily disassembled due to the conventional integration of the frame 2 and the magnet member 1 by molding the resin 4. Since the claws 33 and 34 can be detached from the frame 11 by detaching them from the collar portion 36 and the holder mounting hole 37 of the frame 11, the ferromagnetic body 16 can be easily disassembled and detached from the frame 11. The separability and recyclability of those wastes can be improved.

In addition, the holder 31 holds the ferromagnetic material 16
The ferromagnetic material 16 is provided at the junction between the ferromagnetic material 1 and the ferromagnetic material 1.
6 can be fixed to each other by the holder 31, and the fixing strength of the ferromagnetic material 16 can be increased accordingly. As shown in FIG. 8, the holder 31 may be provided not only at the junction between the ferromagnetic materials 16 but also at each intermediate portion of the ferromagnetic material 16. The fixing strength of the ferromagnetic body 16 can be further increased.

The holder 31 is a holder 41 shown in FIG.
Alternatively, it may be implemented. This holder 41
Is a substrate 42 having an annular shape and corresponding to one of the ferromagnetic bodies 16 by one. A claw 43 for engaging with the flange 36 of the frame 11 is provided on an outer peripheral portion thereof, and a ferromagnetic member is provided on an inner peripheral portion thereof. The upright portions 44 corresponding to the concave portions between the convex portions 17 of the body 16 are respectively
Claws 45 are provided at predetermined intervals corresponding to joint portions between the ferromagnetic bodies 16 and intermediate portions of the ferromagnetic bodies 16, and each upper end of the upright portion 34 has a claw 45 which engages with the holder mounting hole 37. ,
The whole is made of, for example, plastic.

According to this structure, the fixing of the ferromagnetic material 16 to the frame 11 can be easily performed by using one holder 41. In addition, with respect to this one large holder 41, the above-mentioned holder 31 can be formed with a small mold and can be manufactured at low cost.

FIG. 10 shows a third embodiment of the present invention. In the third embodiment, the same parts as those in the second embodiment are denoted by the same reference numerals, and description thereof will be omitted. Only different parts will be described. In this case, in addition to the fixing structure of the ferromagnetic material 16 to the frame 11 by the holder 31 or 41 (the holder 31 is illustrated in the figure), a protrusion 51 is provided on the upper end of the ferromagnetic material 16. On the other hand, in the frame 11, a hole 52 is formed in the step portion 15 and the projection 51 is inserted through the hole 52,
The ferromagnetic body 16 is fixed.

In this case, the fixing strength of the ferromagnetic body 16 to the frame 11 can be further increased. In addition, vibration of the ferromagnetic body 16 can be more reliably prevented. In this case, the holder 31 or 4 with respect to the frame 11
Instead of the structure for fixing the ferromagnetic body 16 according to the first embodiment, the bonding of the first embodiment may be adopted.

As shown in FIG. 11, the protrusion 51 is formed by heating a portion protruding from the hole 52 and crushing it or crushing it without heating, thereby forming a head portion 61 having a diameter larger than that of the hole 52. By doing so, the protrusions 51 can be prevented from coming off, the fixing strength of the ferromagnetic body 16 to the frame 11 can be further increased, and the vibration of the ferromagnetic body 16 can be more reliably prevented.

Further, the projection 51 is changed to a tapered elastic projection 71 shown in FIG. 12 and is press-fitted into a hole 52 having a diameter smaller than that of a portion other than the tip end as shown by an arrow B. In this way, as shown in FIG.
2 is elastically deformed (recovers from expansion) at the portion protruding from the hole 5.
2, the fixing strength of the ferromagnetic body 16 to the frame 11 can be further increased, and the vibration of the ferromagnetic body 16 can be more reliably prevented.

In addition, the present invention is not limited to the embodiment described above and shown in the drawings. In particular, the whole rotor is not limited to the one that is positioned outside the stator and rotates. The present invention can be carried out with appropriate modifications within a range not departing from the gist, for example, a rotary member (inner rotor) positioned inside the child.

[0036]

The present invention is as described above.
The following effects are obtained. According to the rotor of the electric motor of the first aspect, the total number of ferromagnetic materials used can be reduced, and assembling of the ferromagnetic materials can be performed without much trouble, so that manufacturability can be improved.

According to the motor rotor of the second aspect, the magnetic force of the magnetic pole can be increased, and the motor characteristics can be improved accordingly, the thickness of the ferromagnetic material can be reduced, and the frame thickness can be reduced. Can also reduce the weight. According to the rotor of the electric motor of claim 3, the magnetic flux density in the gap between the magnetic pole and the stator approaches a sine wave in a waveform,
Since the number of spatial harmonics is reduced, torque ripple is reduced, and rotation can be performed smoothly, so that cogging, vibration, and noise can be reduced.

According to the rotor of the motor according to the fourth aspect, the ferromagnetic material can be easily and effectively fixed to the frame, and the ferromagnetic material can be easily disassembled and removed from the frame. Recyclability can be improved. According to the rotor of the electric motor of the fifth aspect, the fixing strength of the ferromagnetic material to the frame can be increased. According to the rotor of the electric motor of the sixth aspect, the fixing strength of the ferromagnetic material to the frame can be increased, and the vibration of the ferromagnetic material can be more reliably prevented.

[Brief description of the drawings]

FIG. 1 is a bottom view of a half showing a first embodiment of the present invention.

FIG. 2 is an overall vertical sectional view.

FIG. 3 is a partially enlarged bottom view.

FIG. 4 is a plan view of a shaft support.

FIG. 5 is a view corresponding to FIG. 1 showing a second embodiment of the present invention.

FIG. 6 is a perspective view of a holder alone.

FIG. 7 is a partial longitudinal sectional view.

FIG. 8 is a diagram corresponding to FIG. 1 showing an example in which the number of holders used is increased.

FIG. 9 is a partial perspective view showing a different example of the holder.

FIG. 10 is a view corresponding to FIG. 7, showing a third embodiment of the present invention.

FIG. 11 shows a different example of the fixing structure of the ferromagnetic material.
Partial enlarged view

FIG. 12 is a partially enlarged longitudinal sectional view showing a further different example of a fixing structure of a ferromagnetic material in an exploded state.

FIG. 13 is a diagram corresponding to FIG. 11;

FIG. 14 is a diagram corresponding to FIG. 2 showing a conventional example.

FIG. 15 is a partial cross-sectional view;

[Explanation of symbols]

11 is a frame, 13 is an annular portion (periphery of the frame), 16 is a ferromagnetic material, 17 is a convex portion (magnetic pole), 31, 4
Reference numeral 1 denotes a holder, and reference numerals 51 and 71 denote protrusions (fixed portions).

Continued on the front page F term (reference) 5H002 AA07 AB05 AB07 AC04 AC06 AC08 AE08 5H622 CA02 CA06 CB04 DD04 PP12 PP17 PP19

Claims (6)

[Claims] 1. A rotor for an electric motor, comprising: a ferromagnetic material capable of forming a plurality of magnetic poles, wherein a plurality of such ferromagnetic materials are arranged around a stator side of a frame. 2. The motor rotor according to claim 1, wherein the ferromagnetic material has polar anisotropy. 3. The rotor for an electric motor according to claim 1, wherein the shape of the ferromagnetic material on the stator side is a shape that becomes more convex toward the center of the magnetic pole. 4. The motor rotor according to claim 1, wherein the ferromagnetic material is fixed to the frame by a holder that presses the ferromagnetic material toward the frame. 5. The rotor for an electric motor according to claim 4, wherein the holder is provided at a joint between the ferromagnetic materials. 6. The motor rotor according to claim 1, wherein the ferromagnetic material has a fixing portion fixed to the frame.