JP2004072962A - Outer rotor type motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an outer rotor type motor superior in rotor balance and eliminating the need for adjusting work of the rotor balance. <P>SOLUTION: A cylindrical bearing holder 1c is protrusively arranged at the center of the bottom 1b of a rotor yoke 1 so as to be protruded in a space at the center of an annularly laminated core 4. The rotor yoke 1 is rotatably supported around a fixed shaft 15 via a bearing 14 supported in the bearing holder 1c. The laminated core 4 is supported to the fixed shaft 15 at the tip side of the bearing holder 1c by a spacer 16 fixed to the external periphery of the fixed shaft 15. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an outer rotor type electric motor.
[0002]
[Prior art]
As shown in FIG. 4, a conventional outer rotor type electric motor includes a rotor yoke 1 having a cylindrical portion 1a and a bottom portion 1b closing one end thereof, and a field permanent magnet provided on the inner periphery of the cylindrical portion 1a of the rotor yoke 1. A rotor 3 having a magnet 2, an annular laminated iron core 4 having a salient pole portion 4 a on the outer peripheral side and arranged concentrically with respect to the rotor 3 in a space inside the rotor 3, and a salient pole 4 a of the laminated iron core 4 And a stator 8 having a circuit board 7 supported by the laminated iron core 4 via the support 6 and controlling the energization of the coil 5.
[0003]
The center of the bottom 1 b of the rotor yoke 1 of the rotor 3 is attached to the rotating shaft 9. The rotating shaft 9 is arranged concentrically in the center hole of the annular laminated core 4.
[0004]
An annular flange 10 is disposed on a side surface of the circuit board 7, and a boss 11 is provided upright in a cylindrical shape around a hole of the flange 10. The flange 10 and the boss 11 have been manufactured by aluminum die casting. The annular laminated core 4 is fitted and fixed to the outer periphery of the boss 11. The rotating shaft 9 is rotatably supported in the boss 11 via a bearing 12. A thrust adjusting wave washer 13 is interposed between the step portion of the boss 11 and the bearing 12. The tip of the rotating shaft 9 is stopped by a stopper member 14 on the flange 10 side.
[0005]
[Problems to be solved by the invention]
However, in the outer rotor type electric motor having such a structure, the stator 8 is fixed to the boss 11, the rotor 3 is fixed to the rotating shaft 9, and the rotor 3 and the stator 8 are fixed to the rotating shaft 9 through the bearing 12. Since the rotors are positioned and fixed individually, the rotor balance is poor, and there is a problem that the rotor balance needs to be corrected.
[0006]
In addition, since the assembling work must be performed in both directions with respect to the longitudinal direction of the rotating shaft 9, the assembling workability is poor.
[0007]
Furthermore, since the boss 11 is manufactured integrally with the flange 10 by aluminum die casting, there is a problem that the cost is high and the weight is heavy.
[0008]
SUMMARY OF THE INVENTION An object of the present invention is to provide an outer rotor type electric motor which has a good rotor balance and eliminates the need to correct the rotor balance.
[0009]
Another object of the present invention is to provide an outer rotor type electric motor capable of improving the workability of assembly.
[0010]
Another object of the present invention is to provide an outer rotor type electric motor that can be reduced in weight.
[0011]
[Means for Solving the Problems]
The present invention has a rotor having a rotor yoke having a cylinder portion and a bottom portion closing one end thereof, a rotor having a field permanent magnet provided on an inner periphery of the cylinder portion of the rotor yoke, and a salient pole portion on an outer periphery side. An annular laminated core disposed concentrically with respect to the rotor in a space inside the rotor, a coil wound around the salient pole of the laminated core, and a circuit board supported by the laminated core and controlling energization of the coil. It is intended for an outer rotor type electric motor including a stator.
[0012]
In the outer rotor type electric motor according to the present invention, a cylindrical bearing holder is protruded from the center of the bottom of the rotor yoke so as to project into the center space of the annular laminated core, and the rotor yoke is supported in the bearing holder. The bearing is rotatably supported around a fixed shaft via a fixed bearing, and the laminated core is supported by the fixed shaft via a spacer fixed to the outer periphery of the fixed shaft at the distal end side of the bearing holder. .
[0013]
In such an outer rotor type electric motor, a cylindrical bearing holder is coaxially and integrally protruded from the center of the bottom of the rotor yoke into the cylindrical portion, and the bearing holder is supported on a fixed shaft via a bearing. Since the laminated core is supported by the spacer and the spacer is supported by the fixed shaft, the rotor and the stator are positioned and assembled with respect to the fixed shaft, so that the rotor balance is improved and the work of correcting the rotor balance is improved. It becomes unnecessary. According to this outer rotor type electric motor, the fixed shaft can be assembled by being assembled from one end side in the longitudinal direction, so that the workability of the assembly can be improved. Further, the rotor yoke having the bearing holder can be formed by drawing a magnetic metal plate such as a steel plate, for example, so that the weight can be reduced.
[0014]
In this case, the spacer is provided with a tubular portion that fits in the annular laminated core, and the laminated core can be fitted and supported on the outer periphery of the tubular portion. This makes it possible to reliably support the laminated core in a stable posture.
[0015]
Further, the spacer has a plate shape, and may have a structure for supporting the side surface of the laminated core. By doing so, the spacer does not enter the inside of the laminated core, so that the distance between the outer periphery of the fixed shaft and the inner periphery of the laminated core is increased, and the size of the bearing can be increased.
[0016]
Further, the rotor yoke is configured to have a cylindrical portion formed by a molded product of a plastic magnet, a bottom portion closing one end thereof, and a bearing holder projecting into the cylindrical portion at the center of the bottom portion, and the inner periphery of the cylindrical portion is magnetized. The structure can be a permanent magnet for the field. Even with such a structure, the weight of the rotor yoke can be reduced. Further, the field permanent magnet can be formed by magnetizing a plastic magnet, and the structure can be simplified.
[0017]
Further, the fixed shaft is preferably provided upright on the support. With this configuration, the fixed shaft can be easily mounted.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a longitudinal sectional view showing a first example of an embodiment of an outer rotor type electric motor according to the present invention. Parts corresponding to those in FIG. 4 described above are denoted by the same reference numerals.
[0019]
In the outer rotor type electric motor of the present embodiment, a cylindrical bearing holder 1c is projected from the center of the bottom 1b of the rotor yoke 1 so as to protrude into the space at the center of the annular laminated core 4. The rotor yoke 1 having such a structure is formed by drawing a steel plate. The rotor yoke 1 is rotatably supported around a fixed shaft 15 via a bearing 12 supported in the bearing holder 1c. The fixed shaft 15 is implanted on the flange 10 at a stud portion 15a at the base end.
[0020]
On the distal end side of the bearing holder 1c, the laminated core 4 is supported by the fixed shaft 15 via a spacer 16 fixed to the outer periphery of the fixed shaft 15. In the case of this example, the spacer 16 includes a cylindrical portion 16a that fits inside the annular laminated core 4, and the laminated core 4 is press-fitted and supported on the outer periphery of the cylindrical portion 16a. Between the base 16b of the spacer 16 and the bearing 12 opposed thereto, a thrust adjusting coil spring 17 for applying a pressure to the bearing 12 is provided by being fitted to the fixed shaft 15.
[0021]
In such an outer rotor type electric motor, a spacer 16 having the laminated core 4 fixed to the outer periphery of a cylindrical portion 16a is fitted and fixed to a fixed shaft 15 erected on the flange 10 from the tip end thereof, and then the coil is fixed. The spring 17 is fitted and supported on the base 16b of the spacer 16, then the rotor 3 supporting the bearing 12 is fitted in the bearing holder 1c, and finally the retaining member 14 is fixed to the distal end of the fixed shaft 15 to fix the rotor. Assemble by performing the retaining of 3.
[0022]
In such an outer rotor type electric motor, a cylindrical bearing holder 1c is integrally and coaxially protruded from a center of a bottom 1b of the rotor yoke 1 into a cylindrical portion 1a. Since the fixed core 15 is supported and the laminated core 4 is supported by the spacer 16, and the spacer 16 is supported by the fixed shaft 15, the rotor 3 and the stator 8 are positioned and assembled with respect to the fixed shaft 15. Thus, the rotor balance is improved, and the work of correcting the rotor balance becomes unnecessary. Further, according to the outer rotor type electric motor, the fixed shaft 9 can be assembled by being assembled from one end side in the longitudinal direction, so that the workability of the assembly can be improved. Further, the rotor yoke 1 having the bearing holder 1c can be formed by drawing a magnetic metal plate such as a steel plate, for example, so that the weight can be reduced.
[0023]
Further, as in the present example, when the spacer 16 is provided with the cylindrical portion 16a that fits inside the annular laminated core 4, a structure can be provided in which the laminated core 4 is fitted and supported on the outer periphery of the cylindrical portion 16a. Therefore, the support of the laminated core 4 can be reliably performed in a stable posture.
[0024]
FIG. 2 is a longitudinal sectional view showing a first example of the embodiment of the outer rotor type electric motor according to the present invention. Note that parts corresponding to those in FIG. 1 described above are denoted by the same reference numerals.
[0025]
In the outer rotor type electric motor of the present embodiment, the rotor yoke 1 has a cylindrical portion 1a made of a molded plastic magnet, a bottom portion 1b closing one end thereof, and a bearing holder 1c projecting into the cylindrical portion 1a at the center of the bottom portion 1b. Is configured. The plastic magnet is formed of a mixture of plastic and magnetic powder. The inner circumference of the cylindrical portion 1a is magnetized to form a field permanent magnet 2. Other configurations are the same as those in FIG.
[0026]
When the rotor yoke 1 is made of a molded product of a plastic magnet in this manner, the weight of the rotor yoke 1 can be reduced. If the field permanent magnet 2 can be formed by magnetizing a plastic magnet, the structure can be simplified.
[0027]
FIG. 3 is a longitudinal sectional view showing a third example of the embodiment of the outer rotor type electric motor according to the present invention. Parts corresponding to those in FIG. 2 described above are denoted by the same reference numerals.
[0028]
In the outer rotor type electric motor of the present embodiment, the spacer 16 has a plate shape, the center of which is fixed to the outer periphery of the fixed shaft 15, and one side of the outer periphery supports the side surface of the laminated core 4 via the support 6. are doing. The rotor yoke 1 having the cylindrical portion 1a, the bottom portion 1b, and the bearing holder 1c is made of a molded plastic magnet, as in the second example.
[0029]
When the side surfaces of the laminated core 4 are supported by the spacers 16 in this manner, the spacers 16 do not enter the inside of the laminated core 4, so that the distance between the outer periphery of the fixed shaft 15 and the inner periphery of the laminated core 4 increases, and 12 can be increased in size. Further, similarly to the second example, the rotor yoke 1 is formed of a molded product of a plastic magnet, so that the weight of the rotor yoke 1 can be reduced. In addition, since the field permanent magnet 2 is formed by magnetizing a plastic magnet, the structure can be simplified.
[0030]
Note that, also in the outer rotor type electric motor of the third example, the rotor yoke 1 is formed by drawing a steel plate as in the first example, and the field permanent magnet 2 is fixed to the inner periphery of the cylindrical portion 1a. You can also.
[0031]
In the present invention, the thrust adjusting coil spring 17 is used, but instead, a thrust adjusting wave washer 13 can be used as in the conventional case.
[0032]
【The invention's effect】
In the outer rotor type electric motor according to the present invention, a cylindrical bearing holder is integrally and coaxially protruded from the center of the bottom of the rotor yoke into the cylindrical portion of the rotor yoke, and the bearing holder is supported on a fixed shaft via a bearing. In addition, since the laminated core is supported by the spacer and the spacer is supported by the fixed shaft, the rotor and the stator are positioned and assembled with respect to the fixed shaft, so that the rotor balance is improved and the work of correcting the rotor balance is performed. Becomes unnecessary. According to this outer rotor type electric motor, the fixed shaft can be assembled by being assembled from one end side in the longitudinal direction, so that the workability of the assembly can be improved. Further, the rotor yoke having the bearing holder can be formed by drawing a magnetic metal plate such as a steel plate, for example, so that the weight can be reduced.
[0033]
In this case, if the spacer has a cylindrical portion fitted into the annular laminated core, the laminated core can be reliably supported in a stable posture.
[0034]
In addition, if the spacer has a plate shape and has a structure that supports the side surface of the laminated core, the spacer does not enter the inside of the laminated core, so that the distance between the outer periphery of the fixed shaft and the inner periphery of the laminated core is reduced. And the size of the bearing can be increased.
[0035]
Further, the rotor yoke is formed by a molded product of a plastic magnet to have a cylindrical portion, a bottom portion closing one end thereof, and a bearing holder projecting into the cylindrical portion at the center of the bottom portion, and magnetizing the inner periphery of the cylindrical portion. When the field permanent magnet is formed, the weight of the rotor yoke can be further reduced. When the field permanent magnet is formed by magnetizing a plastic magnet, the structure can be simplified.
[0036]
Further, when the fixed shaft is erected on the support, the fixed shaft can be easily mounted.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a first example of an embodiment of an outer rotor type electric motor according to the present invention.
FIG. 2 is a longitudinal sectional view showing a second example of the embodiment of the outer rotor type electric motor according to the present invention.
FIG. 3 is a longitudinal sectional view showing a third example of the embodiment of the outer rotor type electric motor according to the present invention.
FIG. 4 is a longitudinal sectional view of a conventional outer rotor type electric motor.
[Explanation of symbols]
1 rotor yoke 1a cylinder 1b bottom 1c
2 Field permanent magnet 3 Rotor 4 Laminated core 4a Salient pole 5 Coil 6 Support 7 Circuit board 8 Stator 9 Rotating shaft 10 Flange 11 Boss 12 Bearing 13 Thrust adjustment wave washer 14 Retaining member 15 Fixed shaft 16 Spacer 16a Tube Part 16b Base 17 Coil spring for thrust adjustment

Claims (5)

A rotor having a rotor yoke having a cylindrical portion and a bottom portion closing one end thereof, a rotor having a permanent magnet for field provided on the inner periphery of the cylindrical portion of the rotor yoke, and a rotor having a salient pole portion on the outer peripheral side. An annular laminated core disposed concentrically with respect to the rotor in the space, a coil wound around the salient pole of the laminated core, and a circuit board supported by the laminated core and controlling energization of the coil. In an outer rotor type electric motor including a stator,
At the center of the bottom of the rotor yoke, a cylindrical bearing holder is protruded so as to protrude into the center space of the annular laminated core, and the rotor yoke is provided via a bearing supported in the bearing holder. An outer rotor rotatably supported around a fixed shaft, wherein the laminated core is supported by the fixed shaft via a spacer fixed to an outer periphery of the fixed shaft at a distal end side of the bearing holder. Type electric motor. 2. The outer rotor type electric motor according to claim 1, wherein the spacer includes a tubular portion fitted into the annular laminated core, and the laminated core is supported by being fitted on an outer periphery of the tubular portion. 3. The outer rotor type electric motor according to claim 1, wherein the spacer has a plate shape and supports a side surface of the laminated core. The rotor yoke is configured to have the cylindrical portion and the bottom portion closing one end thereof by a molded product of a plastic magnet, and the bearing holder projecting into the cylindrical portion at the center of the bottom portion, and the inner circumference of the cylindrical portion is The outer rotor type electric motor according to any one of claims 1 to 3, wherein the outer rotor type electric motor is magnetized to form the field permanent magnet. The outer rotor type electric motor according to any one of claims 1 to 4, wherein the fixed shaft is provided upright on a support.

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