JP2004248442A - Dc brushless motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a DC brushless motor which can be manufactured inexpensively and can be assembled easily in a short time. <P>SOLUTION: The rotor comprises a central shaft 1, and a rotor core 2 consisting of three rotor modules 2A, 2B and 2C being fitted, side by side in the axial direction, over the central shaft 1. Each rotor module is provided with three pinholes 8a, 8b and 8c at a specified pitch angle and a different pinhole is selected for each rotor module and inserting with a pin 9 in order to apply a skew equivalently thus positioning the rotor module. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a DC brushless motor.
[0002]
[Prior art]
Conventionally, in a DC brushless motor, a permanent magnet supported by the rotor is twisted around the rotor axis in order to prevent ripples (torque ripples) from occurring in the output torque due to cogging torque and generating noise and vibration. (Skewed).
[0003]
For example, while forming a keyway twisted on the outer peripheral surface of the center shaft, a keyway inclined with respect to the axial direction at a predetermined rotation phase is formed on the inner peripheral surface of the rotor module, and A technique has been proposed in which the key grooves of each rotor module are aligned, and keys are fitted into these key grooves to fix each rotor module, thereby providing equivalent skew (see the following document).
[0004]
[Patent Document 1]
JP-A-7-331772
[Problems to be solved by the invention]
However, according to the above-mentioned prior art, there is a problem that the key groove cannot be easily formed because it is a spiral groove, and a skill is required for assembling the rotor module and the center shaft.
[0006]
Therefore, an object of the present invention is to provide a DC brushless motor that can be manufactured at low cost and that can be easily and quickly assembled.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, a DC brushless motor according to the present invention is directed to a DC brushless motor including a rotor including a central axis and a plurality of rotor modules that are externally arranged and fitted in the central axis in the axial direction. In the module, a plurality of pin holes are provided at a predetermined pitch angle in the circumferential direction on a circumference at a predetermined distance from the axis and penetrate in parallel with the axis, and are externally fitted to the center axis. The pin holes at different positions in the circumferential direction are selected for each rotor module in accordance with the order of the rotor modules, and the pins are inserted through these selected pin holes, and the rotor modules are skewed and positioned. It is.
[0008]
According to this, by selecting pin holes at different positions in the circumferential direction from a plurality of pin holes for each rotor module and inserting the pins, each rotor module is skewed and positioned. In addition, it can be assembled in a short time. Further, since it is relatively easy and inexpensive to form a pin hole in each rotor module in parallel with the axis, it is possible to obtain an effect that a DC brushless motor can be manufactured at low cost in combination with the above effects. Can be.
[0009]
In the present invention, the pitch angle can be obtained by equally dividing the optimum skew angle of the DC brushless motor by one less than the number of rotor modules used in the DC brushless motor. Pins are formed to have the same length in the direction and at least as many pin holes as the number of rotor modules used in the DC brushless motor, and are located at positions shifted one by one in the circumferential direction for each rotor module. A configuration may be adopted in which a hole is selected and each rotor module is skewed. Note that as the optimum skew angle, a value obtained in consideration of torque ripple, magnetic interference of a permanent magnet used in each rotor module, or the like may be used.
[0010]
According to this, since each rotor module can be formed in the same shape, it is not necessary to use a rotor module having a different shape depending on the order in which the outer modules are fitted to the center shaft, so that the cost can be reduced and the order in which the outer modules are fitted is bothersome. Since it is possible to assemble without performing, the assembling time can be reduced. Further, since the pin holes which are shifted one by one in the circumferential direction may be selected for each rotor module, the assembling work can be performed extremely easily and smoothly without losing the pin holes to be selected. be able to.
[0011]
By the way, each of the rotor modules can be supported on the central axis so as to be relatively non-rotatable by being fitted to the central axis by, for example, a tight fit such as a close fit or a tight fit. , A pair of core supports may be fitted around the center axis so as to be relatively non-rotatable, and the core supports may support both ends of the pin. According to this configuration, the workability of assembling the rotor modules can be improved, and each rotor module can be reliably supported.
[0012]
Of course, in the present invention, the structure in which each rotor module supports the permanent magnet and the shape of the permanent magnet are not particularly limited. That is, as a structure for supporting the permanent magnet on each rotor module, a structure for supporting the permanent magnet on the outer peripheral surface of the rotor module, a structure for recessing and supporting a part or all of the permanent magnet on the outer peripheral surface of the rotor module, What is necessary is just to employ | adopt the structure etc. which support so that a permanent magnet may not be exposed to the outer peripheral surface of a rotor module. Further, the shape of the permanent magnet includes an arc plate shape centered on the axis of the rotor module, a flat plate shape orthogonal to the diameter of the rotor module, an outwardly convex semi-cylindrical shape orthogonal to the diameter of the rotor module, and a shape of the rotor module. What is necessary is just to employ | adopt the flat plate shape arrange | positioned radially centering on an axial center.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
A DC brushless motor according to an embodiment of the present invention will be specifically described below with reference to the drawings.
[0014]
As shown in FIG. 1, the rotor of the DC brushless motor according to one embodiment of the present invention includes a central shaft 1 and three upper and lower rotor modules 2A, 2B which are externally fitted on the central shaft 1 in an axial direction. And a rotor core 2 made of 2C.
[0015]
FIG. 2 is a perspective view of the rotor module 2A. As shown in FIG. 2, the rotor module 2A includes a core 3 and four permanent magnets 4 supported by the core 3, and the core 3 is laminated in the axial direction. And a predetermined number of core plates 5. Although not shown, both the rotor modules 2B and 2C have the same configuration as the rotor module 2A shown in FIG. 2. Therefore, the rotor modules 2A, 2B and 2C can be mounted on the center shaft 1 in the reverse order. It is possible.
[0016]
FIG. 3 is a plan view of the core plate 5. As shown in FIGS. 2 and 3, each core plate 5 has a shaft hole 6 through which the central shaft 1 is inserted, and a 90 ° opening at the peripheral edge thereof. Four magnet insertion holes 7 formed in a slit shape perpendicular to the radial direction, and pin holes 8a, 8b, 8c are formed.
[0017]
FIG. 4 is an enlarged plan view showing the I-circle surrounding portion shown in FIG. 3. As shown in FIG. 4, each core plate 5 is provided at a certain distance from its axis. The same number as the rotor modules 2A, 2B, 2C, that is, three pin holes 8a, 8b, 8c are formed in parallel with the axis at a predetermined pitch angle p / 2 in the direction. Here, the angle p is an optimum skew angle in this DC brushless motor, and the pitch angle p / 2 is a value obtained by equally dividing the skew angle p by one less than the number of rotor modules (3), that is, by two. I have. In this embodiment, a set of three pin holes 8a, 8b, 8c is provided at four locations at regular intervals of 90 ° in the circumferential direction.
[0018]
Then, as shown in FIG. 3, by laminating a predetermined number of core plates 5, the shaft hole 6, the magnet insertion hole 7, and the pin holes 8a, 8b, 8c are formed so as to communicate in the axial direction. As shown in FIG. 2, permanent magnets 4 are inserted into the respective magnet insertion holes 7 in which the core plates 5 are stacked and communicated in the axial direction, and are fixed to the core plates 5 by, for example, bonding.
[0019]
The locations where the pin holes 8a, 8b, 8c are provided are not limited to four locations, and may be at least one location. However, in order to prevent the rotor 2 from oscillating, it is provided at two or more locations. Is preferred. Further, the shape, size and arrangement of the magnet insertion holes 7 may be appropriately designed according to the shape, size and arrangement of the permanent magnets 4 to be used irrespective of the positions of the pin holes 8a, 8b and 8c.
[0020]
As shown in FIG. 1, each of the rotor modules 2A, 2B, and 2C is assembled on the center axis 1 by sequentially shifting the pin holes one by one in the circumferential direction, thereby forming the rotor modules 2A aligned in a straight line from top to bottom. Pins 9 are inserted through the pin holes 8a, 8b of the rotor module 2B, and 8c of the rotor module 2C (here, since four pin holes are provided, one pin 9 is inserted into each of them. ) Positioned.
[0021]
By the way, in this embodiment, a pair of core supports 10 are externally fitted to the center shaft 1 so as to be relatively non-rotatable by tight fitting such as, for example, stop fitting with the three upper and lower rotor modules 2A, 2B, 2C interposed therebetween. Each core support 10 is provided with a pin hole 11 at intervals of 90 ° in the circumferential direction on the circumference separated from the axis of the core support 10 by the same distance as the pin holes 8a, 8b, 8c of the core plate 5. Is formed.
[0022]
Then, for example, the pins 9 are sequentially inserted from below the lower core support 10 into the pin holes 11 of the lower core support 10, the pin holes 8c of the rotor module 2C, the pin holes 8b of the rotor module 2B, and the pin holes 8a of the rotor module 2A. , Into the pin hole 11 of the upper core support 10. Here, a head 9a is provided at the lower end of the pin 9, and a screw portion 9b is provided at the upper end thereof. The head 9a is received on the lower surface of the lower core support 10 and the upper core 9a is received. The nut 12 is screwed into the screw portion 9b protruding above the support 10 and tightened to abut on the upper surface of the upper core support 10, whereby the upper and lower core supports 10 and the rotor modules 2A, 2B, 2C are tightened. Fixed.
[0023]
Note that the fitting between the rotor modules 2A, 2B, 2C and the central shaft 1 may be tight fitting such as a stop fitting or a tight fitting. However, here, each rotor module 2A, 2B, 2C and the central shaft 1 are fitted. Numeral 1 is a clearance fit having a small gap between them, and by rotating the rotor modules 2A, 2B, 2C around the central axis 1 while inserting the pins 9, the pin holes of each rotor module are easily selected. To adjust the position. Further, the fitting between the core support 10 and the central shaft 1 is a stop fit so that the core support 10 does not easily move in the axial direction and the direction around the axis with respect to the central shaft 1, but it is a gap fitting. The core support 10 may be fixed to the center shaft 1 by screws, pins, keys, nuts, or the like.
[0024]
Further, the fixing method of the pin 9 is not limited to the above-mentioned method. For example, a snap ring for receiving the end face of the pin 9 is fitted in the pin hole 11 of each core support 10, or the end of the pin 9 is fitted to each core support 10. The ends of the pins 9 are tightly fitted into the pin holes 11 of the core supports 10 by screwing the ends, pinning the ends of the pins 9 to the core supports 10, or by tightly fitting or tightly fitting the pins 9. Can be combined.
[0025]
Now, according to this embodiment, the rotor module 2B is positioned so as to be circumferentially shifted by a pitch angle p / 2 with respect to the rotor module 2A, and the rotor module 2A2C is positioned at a pitch angle p / 2 with respect to the rotor module 2B. Is positioned in the circumferential direction by a pitch angle p, so that the rotor 2 can be equally skewed by dividing it into three equal parts in the axial direction. Therefore, the effect that the torque ripple can be reduced by reducing the cogging torque, the effect that the noise and vibration can be reduced by reducing the cogging torque, and the effect that the high frequency component of the induced voltage can be reduced. And so on.
[0026]
Further, according to this embodiment, three rotor modules 2A, 2B, and 2C having the same configuration can be used, so that the cost can be reduced by using a single type of core plate 5 and mass-production of a small number of products. In addition, there is no need to match the stacking order of the core plates 5, and the effect that the rotor module can be easily assembled in a short time can be obtained. Further, it is necessary to form a spiral key groove on the outer peripheral surface of the central shaft 1 or use a spiral key, and assemble each rotor module without worrying about the order of fitting to the central shaft 1. Therefore, the center shaft 1 can be manufactured at low cost, and the assembly of each rotor module and the center shaft 1 can be performed easily and in a short time.
[0027]
【The invention's effect】
As described above, according to the present invention, the rotor can be skewed equivalently, whereby the cogging torque can be reduced and the torque ripple can be reduced, and the cogging torque can be reduced. An effect that noise and vibration can be reduced, an effect that a high frequency component of an induced voltage can be reduced, and the like can be obtained.
[0028]
Further, according to the present invention, since the core plates of any rotor modules can be formed in the same shape, the effect that the core plates can be produced in small quantities and in large quantities and inexpensive can be obtained. Therefore, the rotor module can be easily assembled in a short time. Further, since a similarly configured rotor module can be used, the assembly of each rotor module and the central shaft can be performed easily and in a short time without having to worry about the order of fitting to the central shaft. it can.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view of the present invention.
FIG. 2 is a perspective view of the present invention.
FIG. 3 is a perspective view of the present invention.
FIG. 4 is a plan view of the present invention.
[Explanation of symbols]
Reference Signs List 1 center axis 2 rotor core 2A rotor module 2B rotor module 2C rotor module 4 permanent magnet 8a pin hole 8b pin hole 8c pin hole 9 pin 10 core support p skew angle

Claims (3)

In a DC brushless motor including a central shaft and a rotor including a plurality of rotor modules that are externally arranged side by side in the axial direction on the central shaft,
In each rotor module, a plurality of pin holes are penetrated in parallel with the axis at a predetermined pitch angle in the circumferential direction on a circumference at a predetermined distance from the axis,
Pin holes at circumferentially different positions are selected for each rotor module in accordance with the order in which the rotor modules are externally fitted to the center axis, and pins are inserted through these selected pin holes, whereby each rotor module is skewed and positioned. DC brushless motor characterized in that: The pitch angle is obtained by equally dividing the optimum skew angle of the DC brushless motor by one less than the number of rotor modules used in the DC brushless motor,
Each rotor module is formed to have the same length in the axial direction, and has at least as many pin holes as the number of rotor modules used in the DC brushless motor,
2. The DC brushless motor according to claim 1, wherein a pin hole at a position shifted one by one in a circumferential direction is selected for each rotor module, and each rotor module is skewed. 3. The DC brushless motor according to claim 1, wherein a pair of core supports are fitted around the center shaft so as to sandwich the rotor module, and both ends of the pins are supported by the core supports.

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