JP3672775B2 - Brushless motor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a brushless motor, which is a kind of small motor used mainly as a drive source for a blower fan such as a room air conditioner, a water heater, and a ventilation fan.
[0002]
[Prior art]
  In recent years, this type of brushless motor has been required to have high quality, high output, and high efficiency while realizing downsizing, cost reduction, reduction in the number of parts and processing steps, and restraining investment in facilities and molds. ing. The high output and high efficiency of the brushless motor can be achieved by expanding the slot area to the magnetic saturation limit, using high-density mounting windings, and using a magnet with a high magnetic flux density for the rotor. Has been. Furthermore, recently, high efficiency has been achieved by increasing the number of poles.
[0003]
  The magnet is divided into a ring-type magnet and a segment-type magnet in terms of shape, and the segment-type magnet has a higher magnetic flux density. In addition, when magnetic powder is molded in a mold, it is classified into anisotropic magnets and isotropic magnets depending on whether it is oriented by applying a magnetic field or not by applying a magnetic field. The anisotropic magnet is divided into a radial anisotropic magnet, a polar anisotropic magnet, and an axial anisotropy according to the magnetic field orientation, and the polar anisotropic magnet has a magnetic flux density of about 20% that of the radial anisotropic magnet. Since the magnetization waveform is a sine wave, polar anisotropic magnets have been used for low vibration, high output and high efficiency.
[0004]
  Conventionally, an example of this type of brushless motor is shown in FIGS. 12 and 13. Hereinafter, the configuration will be described with reference to FIGS. 12 and 13.
[0005]
  As shown in the figure, the stator 54 is configured by insulating a stator core 51 having six slots by an insulator 52 by integral molding or sandwiching from the axial direction, and winding an armature winding 53 directly. In the magnet rotor 55, four ferrite anisotropic segment magnets 58 are attached to a rotor core 57 into which a shaft 56 is press-fitted, and the axial length of the ferrite anisotropic segment magnet 58 is the axis of the stator core 51. Reference numeral 59 denotes a printed circuit board on which a Hall IC 60 that is a position detection element for detecting the magnetic pole position of the magnet rotor 55 and a drive IC 61 that controls energization to the armature winding 53 are mounted. The Hall IC 60 is configured to detect the leakage magnetic flux of the ferrite anisotropic segment magnet 58. However, in such a 6-slot 4-pole non-printing motor, since extremely high efficiency cannot be achieved, the number of slots of the stator core 51 is changed from 6 to 9 or 12 and the number of poles of the magnet rotor 55 is increased. There has been proposed a configuration in which the efficiency is increased by changing from 4 poles to 8 poles. However, increasing the number of poles of the magnet rotor 55 from 4 poles to 8 poles doubles the number of processing steps of the magnet rotor 55, which increases costs. The use of sex magnets is increasing.
[0006]
[Problems to be solved by the invention]
  According to such a conventional brushless motor, when the printed circuit board 59 is built in the motor and the magnetic pole position of the magnet rotor 55 is detected using the Hall IC 60, at least the printed circuit board having the axial length of the magnet 58 is detected. The 59 side needs to be equal to or longer than the axial length of the armature winding 53 wound around the stator core 51. However, in this method, since the axial center of the stator core 51 and the axial center of the magnet 58 are shifted, the magnetic center is shifted, and the magnetic force between the stator core 51 and the magnet 58 causes an imbalance in the axial direction. There was a problem that the vibration in the direction became large.
[0007]
  Similarly, if the axial length of the magnet 58 is also increased to the opposite side of the printed circuit board 59, the magnetic center is not displaced between the magnet 58 and the stator core 51, but the axial length of the brushless motor is long. There was a problem that it was too thin to be thinned.
[0008]
  Further, when the axial length of the magnet 58 becomes abnormally longer in the stator core 51 than the axial length, the stator core 51 is magnetically saturated, so that the induced voltage phase advances more than the sensor signal and is induced. Since the peak of the voltage waveform is distorted into a concave shape, the energization phase is delayed, the power consumption increases abnormally, the output decreases, the torque ripple and the torque change rate increase, and the vibration in the rotational direction increases. .
[0009]
  Further, a non-printing motor (Japanese Patent Laid-Open No. 10-322999) in which a ring-shaped first permanent magnet is bonded and fixed to the outer periphery of an annular rotor core, and a second permanent magnet for a sensor is bonded and fixed to the end face of the rotor core. The purpose of this is to place the magnetic sensor in a free position where the electrical insulator does not interfere. In the brushless motor of this configuration, the permanent magnet is placed on the rotor core. Since it is necessary to perform the adhesive fixing twice, and it takes about one hour using a high temperature furnace to perform the adhesive fixing with stable quality, there is a problem that the processing man-hours increase and the capital investment increases. . In particular, with respect to the position where the second permanent magnet is bonded and fixed, there is a problem that even a small amount of misalignment causes a weight imbalance or the change intervals of the sensor signals are not uniform. Further, the bonding surface for bonding the second permanent magnet is a flat surface, and there is a problem that the accuracy of the perpendicularity to the magnetic pole surface must be increased.
[0010]
  Further, although not disclosed in Japanese Patent Laid-Open No. 10-322999, when a sintered polar anisotropic magnet is used for the first permanent magnet, a rotor core is not necessary, but it is bonded to the rotor core. Further, it is essential to polish the inner diameter of the sintered polar anisotropic magnet. However, since the inner diameter polishing of the sintered polar anisotropic magnet is difficult to process, there is a problem that the cost becomes abnormally high.
[0011]
  The present invention solves such a conventional problem, and can reduce costs and processing man-hours without causing deterioration of characteristics such as large vibrations, and has a built-in printed circuit board on which electronic components are mounted. However, it is an object of the present invention to provide a brushless motor that can be reduced in thickness, size, weight, power consumption, and quality.
[0012]
[Means for Solving the Problems]
  In order to achieve the above object, the brushless motor of the present invention uses a sintered polar anisotropic magnet as the magnet rotor. An annular main magnetic pole portion, and a sensor magnetic pole portion having an outer diameter smaller than the outer diameter of the main magnetic pole portion and a fixing through hole made of a substantially annular resin magnet or rubber magnet, The portion is fixed to the shaft via a holding portion, and the holding portion has a protrusion for fixing the magnetic pole portion for sensor, and a through hole of the magnetic pole portion for sensor is fitted into the protrusion, and the protrusion A brushless electric motor characterized in that the sensor magnetic pole part is fixed by crushing the tip part of the sensorThe configuration is as follows.
[0013]
  According to the present invention,The magnetic center of the stator core can be aligned with the magnetic center of the main magnetic pole, and the magnet volume of the main magnetic pole can be reduced without deteriorating characteristics such as increased vibration. Accurate alignment of the magnetic pole part can be easily performed,The volume of the material that forms the holding part can be reduced, the need for bonding using a high-temperature furnace and the like is eliminated, the processing man-hours, processing costs, and investment costs for manufacturing the magnet rotor can be reduced, and weight imbalance and sensor signal non-uniformity are reduced. Since it can be suppressed, a brushless motor with low cost, high quality and high performance can be obtained.
[0014]
  Other means are:The through hole provided in the magnetic pole part for the sensor is a stepped through hole or a mortar-like through hole, and the small diameter side of the through hole is positioned on the main magnetic pole part side in the protrusion provided in the holding part. A brushless motor, wherein the sensor magnetic pole is fixed by crushing the tip of the protrusion into the large diameter space of the stepped through-hole or mortar-shaped through-hole.The configuration is as follows.
[0015]
  According to the present invention, the material volume for forming the holding portion can be reduced, the use of a high-temperature furnace or the like is not required, the processing man-hours for manufacturing the magnet rotor, the processing costs, and the investment costs can be reduced. Since the nonuniformity of the sensor signal can be suppressed and the axial length can be further shortened, a brushless motor that achieves cost reduction, high quality, high performance, and further miniaturization can be obtained.
[0016]
  The other means is a configuration of a magnet rotor in which at least a tip portion of the protrusion of the holding portion is thin.
[0017]
  According to the present invention, the material volume for forming the holding portion can be reduced, the use of a high-temperature furnace or the like is not required, and the processing time required for fixing the magnetic pole portion for the sensor can be greatly reduced. Can reduce the number of processing man-hours, processing costs, and investment costs, and can suppress weight imbalance and sensor signal non-uniformity, resulting in further cost reduction, higher quality, higher performance, and smaller brushless motors. .
[0018]
DETAILED DESCRIPTION OF THE INVENTION
  In the present invention, the magnet rotor is fixed to an annular main magnetic pole portion made of a sintered polar anisotropic magnet and a substantially annular resin magnet or rubber magnet having an outer diameter smaller than the outer diameter of the main magnetic pole portion. The main magnetic pole portion is fixed to the shaft through a holding portion, and the holding portion has a protrusion for fixing the sensor magnetic pole portion, and the protrusion includes the protrusion. A brushless motor, wherein the sensor magnetic pole part is fixed by fitting a through hole of the sensor magnetic pole part and crushing a tip part of the protrusion.It is made up ofThe magnetic center of the stator core and the magnetic center of the main magnetic pole that generate rotational torque can be reduced by securing the appropriate interlinkage magnetic flux and reducing the magnet volume, such as shortening the axial length of the magnet that forms the main magnetic pole. And the magnetic saturation is suppressed, the interlinkage magnetic flux becomes a sine wave, and the accurate positioning of the magnetic pole part for the sensor with respect to the main magnetic pole part becomes easy.The material volume of the holding part is reduced, and the bonding using a high temperature furnace or the like is not required.
[0019]
  Also,The through hole provided in the magnetic pole part for the sensor is a stepped through hole or a mortar-like through hole, and the small diameter side of the through hole is positioned on the main magnetic pole part side in the protrusion provided in the holding part. A brushless electric motor characterized in that the sensor magnetic pole part is fixed by crushing and fitting the tip of the protrusion into the large-diameter space of the stepped through hole or mortar-shaped through holeIt is made up ofAccurate alignment of the sensor magnetic pole with respect to the main magnetic pole becomes easier,The material volume of the holding part is reduced, the use of a high-temperature furnace or the like is not required, and the axial length of the magnet rotor is shortened.
[0020]
  In addition, at least the tip of the protrusion of the holding part has a thin magnetic rotor configuration, which reduces the material volume of the holding part and eliminates the need for bonding using a high-temperature furnace, etc. This has the effect of shortening the time required for fixing the magnetic pole part to the holding part.
[0021]
  Embodiments of the present invention will be described below with reference to FIGS.
[0022]
【Example】
  (referenceExample 1)
  As shown in FIGS. 1 and 2, reference numeral 1 denotes a stator in which an armature winding 3 is wound around an insulator 2 formed of an insulating material on a stator core 4 having a plurality of slots. Is molded with a thermosetting resin 16 to form a jacket, and 17 is a bracket holding the bearing 14. Reference numeral 10 denotes a printed circuit board on which the Hall IC 11, the drive IC 12, and the electronic component 13 are mounted. Reference numeral 8 denotes a magnet rotor, which is composed of a main magnetic pole portion 6 made of a sintered ferrite polar anisotropic magnet and an isotropic resin magnet. The annular sensor magnetic pole portions 7 are arranged with a gap 5 a in the axial direction of the shaft 9, formed integrally with the thermoplastic resin 5, and also formed in the gap 5 a between the main magnetic pole portion 6 and the sensor magnetic pole portion 7. A thermoplastic resin 5 is interposed. Further, the space IC 15 is provided in the range from the outer diameter of the sensor magnetic pole section 7 to the outer side and the outer diameter of the main magnetic pole section 6, and the drive IC 12 and the like are mounted on the printed circuit board 10. Since the length of the connection leg 12a (height from the end face of the printed circuit board 10) that is electrically connected to the printed circuit board 10 is 2 mm or more at the position facing the magnetic pole part 7, the print of the connection leg 12a is performed. The solder part 12b to the substrate 10 is disposed so as to be positioned in the space part 15. Similarly, the electronic component 13a such as a Zener diode or a capacitor having a height of 2 mm or more in the electronic part 13 is also positioned in the space part 15. Has been placed.
[0023]
  According to such a brushless motor of the present invention, the main magnetic pole part 6 is formed of a sintered ferrite polar anisotropic magnet, and the sensor magnetic pole part 7 is an isotropic resin smaller than the outer diameter of the main magnetic pole part 6. The main magnetic pole portion 6 and the sensor magnetic pole portion 7 are formed of magnets, and the magnetic rotor portion 8 is arranged side by side in the axial direction. The magnet volume can be reduced by shortening the direction length and the magnetic center of the stator core 4 coincides with the magnetic center of the main magnetic pole portion 6 that generates rotational torque, so that the occurrence of axial vibration can be suppressed. In addition, since magnetic saturation is suppressed and the linkage flux becomes a sine wave, operation can always be performed with the optimum energization phase with respect to the induced voltage phase, so an increase in torque ripple and torque change rate is suppressed, and vibration in the rotational direction is suppressed. Increase is suppressed. Moreover, since the magnet volume can be reduced, cost reduction, size reduction, and weight reduction can be achieved. Therefore, a low-cost brushless motor with low cost, low vibration, small size, and light weight can be obtained.
[0024]
  In addition, the main magnetic pole portion 6 made of sintered ferrite polar anisotropic magnet, the magnetic pole portion 7 for sensor made of isotropic resin magnet, and the shaft 9 are integrally molded and solidified with a thermoplastic resin 5 such as PBT to rotate the magnet. By configuring the rotor 8, it is not necessary to polish the inner diameter of the sintered ferrite polar anisotropic magnet and the isotropic resin magnet and press-fit the shaft 9 into the rotor core and the rotor core. However, stable production can be achieved at low cost, the number of parts can be reduced, and the processing time until the magnet rotor 8 is completed can be reduced. Furthermore, since all the parts are positioned and manufactured on the basis of the outer shape with the resin molding die, it is possible to suppress weight imbalance and sensor signal non-uniformity. Therefore, a cheaper brushless motor with lower vibration, smaller size, lighter weight, lower power consumption, higher quality, and higher performance can be obtained.
[0025]
  Also, by forming the gap 5a between the main magnetic pole part 6 and the sensor magnetic pole part 7 with the thermoplastic resin 5 interposed therebetween, the parallelism and surface of the axial end faces of the main magnetic pole part 6 and the sensor magnetic pole part 7 are formed. Since it is not necessary to increase the accuracy of the roughness and the perpendicularity to the magnetic pole surface, it is not necessary to increase the accuracy of the magnet mold and the end surface polishing, and the cost can be reduced. Therefore, a lower-price electric motor with a lower cost can be obtained.
[0026]
  Further, the solder part 12b that electrically connects the electronic component 13a having a height of 2 mm or more and the connecting leg 12a of the driving IC 12 and the like is arranged on the outside and main magnetic poles from the outer diameter of the isotropic resin magnet that is the magnetic pole part 7 for sensors. By adopting a configuration in which the sintered ferrite polar anisotropic magnet which is the portion 6 is located in the space portion 15 in the range inside the outer diameter of the sintered ferrite polar anisotropic magnet, the outer diameter and the sintered ferrite pole anisotropic from the outer diameter of the isotropic resin magnet Since the space portion 15 in the range inside the outer diameter of the magnet can be effectively used, the axial length of the brushless motor can be further shortened, and the amount of the thermosetting resin 16 can be reduced. Accordingly, a brushless motor that is further reduced in size, weight, and cost can be obtained.
[0027]
  In addition,referenceIn Example 1, an isotropic resin magnet is used as the magnetic pole portion 7 for the sensor. However, an isotropic rubber magnet may be used, and there is no difference in the operational effect. Furthermore, it may be a magnet rotor using an axially anisotropic resin magnet or an axially anisotropic rubber magnet in which the axis of easy magnetization of ferrite fine particles of magnetic powder is oriented in the axial direction. The axial length of the part can also be shortened. Furthermore, the magnetizing voltage of the magnetic pole part for the sensor can be lowered, the electric power required for processing can be reduced, and the decrease in the magnetic flux amount in the vicinity of the magnetic pole part for the sensor in the main magnetic pole part can be suppressed. The amount of magnetic flux interlinked with increases. Therefore, a brushless motor with low vibration, further lower cost, smaller size, lighter weight, and lower power consumption can be obtained.
[0028]
  Also,referenceIn Example 1, the thermoplastic resin 5 is integrally formed in the gap 5a between the main magnetic pole part 6 and the sensor magnetic pole part 7, but a brushless motor that can be reduced in vibration and reduced in size without being interposed is obtained.
[0029]
  (Example1)
  As shown in FIGS. 3 to 10, reference numeral 18 denotes a magnet rotor formed by integrally forming a main magnetic pole portion 6 made of a sintered ferrite polar anisotropic magnet on a shaft 9 with a thermoplastic resin such as PBT. The main magnetic pole portion 6 is held by the holding portion 19. Reference numeral 20 denotes a plurality of protrusions provided integrally with the holding portion 19 so as to be substantially upright in the axial direction, and positions and holds the sensor magnetic pole portion 21. Further, the sensor magnetic pole part side axial end surface 19a of the holding part 19 provided with the protrusion 20 is formed so as to partially cover the sensor magnetic pole part side axial end face 6a of the main magnetic pole part 6 in an annular shape. The sensor magnetic pole portion 21 is formed by punching an anisotropic rubber magnet into a substantially annular shape by a simple and inexpensive mold such as a Thomson type, and a plurality of through holes 22 for fitting into the protrusions 20. Is also punched at the same time. The sensor magnetic pole part 21 is fixed by fitting the through hole 22 to the protrusion 20 and then crushing and fixing the tip 20a of the protrusion 20 by ultrasonic welding, heat welding, high frequency welding, impulse welding or the like. Other configurations arereferenceSame as Example 1.
[0030]
  According to such a brushless motor of the present invention, the holding part 19 integrally molds the main magnetic pole part 6 and the shaft 9 with a thermoplastic resin such as PBT, so that the main magnetic pole part 6 and the protrusion with respect to the shaft center of the shaft 9 are formed. The position accuracy of the portion 20 and the sensor magnetic pole portion 21 can be increased, and the number of processing steps can be reduced, so that a brushless motor with high quality and low cost can be obtained.
[0031]
  Further, the sensor magnetic pole part side axial end surface 19a of the holding part 19 provided with the protrusion 20 is formed so as to partially cover the sensor magnetic pole part side axial end face 6a of the main magnetic pole part 6 in an annular shape. Since it is not necessary to increase the accuracy of the parallelism, surface roughness, and perpendicularity to the magnetic pole surface of the main magnetic pole portion 6 and the sensor magnetic pole portion 21, there is no need to increase the accuracy of the magnet mold and end face polishing. Thus, the cost can be reduced. Therefore, a lower-price electric motor with a lower cost can be obtained.
[0032]
  Further, by adopting a structure in which the through hole 22 of the sensor magnetic pole part 21 is fitted to the protrusion 20 of the holding part 19, accurate alignment of the sensor magnetic pole part 21 with respect to the main magnetic pole part 6 is facilitated. Since the parallelism between the outer diameter of the main magnetic pole portion 6 and the outer diameter of the sensor magnetic pole portion 21 becomes uniform, weight imbalance and sensor signal non-uniformity can be suppressed. Is obtained.
[0033]
  Further, by forming the magnet rotor 18 by crushing the tip portion 20a of the protrusion 20 and fixing the magnetic pole portion 21 for the sensor, there is no need for bonding using a high temperature furnace or the like, and the number of processing steps for manufacturing the magnet rotor , Machining costs and investment costs can be reduced, and the production of the magnet rotor 18 can be performed in two steps, so that the production tact time is shortened, the production capacity is increased, and the cost can be reduced. A brush motor is obtained.
[0034]
  Further, since the rubber magnet can be formed by punching with a Thomson type having a simple structure, the investment cost can be greatly reduced, and a brushless motor with further reduced costs can be obtained.
[0035]
  Examples1Then, the holding part 19 is formed by integrally forming the main magnetic pole part 6 made of sintered ferrite polar anisotropic magnet on the shaft 9 with a thermoplastic resin such as PBT, but it is made of a soft metal such as aluminum, zinc, magnesium alloy. A holding part may be formed, and a difference is not produced in the effect. Also, by making the holding part a soft metal, 80Every timeIt is possible to use a brushless motor in a high temperature range exceeding.
[0036]
  Further, as shown in FIGS. 6A and 6B, by forming the tip 20b of the protrusion 20 with a thin shape such as an annular shape, the tip 20b can be easily crushed and the processing time is shortened. Therefore, the production tact time is shortened, the production capacity is increased, and the cost can be reduced, so that a lower-cost brushless motor can be obtained.
[0037]
  Further, as shown in FIGS. 7A, 7B, and 8, a resin magnet is formed so that the through hole 22 becomes a stepped through hole 22a or a mortar-shaped through hole 22c, and the magnetic pole portion 21a for the sensor is formed. By forming, the fitting to the protrusion 20 is facilitated, so that the machining time is shortened, the production tact time is shortened, the production capacity is increased, and the cost can be reduced. Is obtained.
[0038]
  Further, only the large-diameter portion of the stepped through hole may be formed in a mortar shape, and there is no difference in the function and effect.
[0039]
  Further, as shown in FIGS. 9 and 10, the small diameter side of the stepped through hole 22 a is positioned on the main magnetic pole portion 6 side and fitted to the protrusion 20, and the tip 20 a of the protrusion 20 is connected to the stepped through hole. The axial length of the magnet portion of the magnet rotor 18a can be shortened by crushing it into the large-diameter space 22b of the 22a and fixing the sensor magnetic pole portion 21a, so that the printed circuit board 10 can be brought closer to the magnet portion. Thus, since the axial length of the brushless motor can be further shortened, a brushless motor that is further reduced in weight, size, and cost can be obtained.
[0040]
  (referenceExample2)
  As shown in FIG. 11, reference numeral 23 denotes a sensor magnetic pole made of an axially anisotropic resin magnet having a main magnetic pole portion 6 made of a sintered ferrite polar anisotropic magnet and a plurality of stepped through holes 22 a on the shaft 9. The magnet rotor is formed by integrally forming the portion 21 a with a space in the axial direction, filling the stepped through hole 22 a with a thermoplastic resin 24 such as PBT, and integrally molding the thermoplastic resin 24. Is filled in the large-diameter space 22b of the stepped through hole 22a. Other configurations are the same as those of the first embodiment.
[0041]
  According to such a brushless motor of the present invention, since the sensor magnetic pole portion 21a is firmly fixed, the idling of the sensor magnetic pole portion 21a, the weight imbalance, and the nonuniformity of the sensor signal can be reliably suppressed. A quality brushless motor can be obtained.
[0042]
  Further, since no bonding using a high-temperature furnace or the like is required, and the processing man-hours, processing costs, and investment costs for manufacturing the magnet rotor 23 can be reduced, a low-cost brushless motor can be obtained.
[0043]
  Further, the amount of resin is reduced by keeping the filling of the thermoplastic resin 24 in the large-diameter space 22b of the stepped through hole 22a and not forming the sensor so as to hold the end face in the axial direction of the magnetic pole part 21a for the sensor. In addition, the forming tact can be shortened and the axial length of the magnet portion of the magnet rotor 23 can be shortened, so that the printed circuit board can be brought closer to the magnet portion, and the axial length of the brushless motor can be further shortened. As a result, a brushless motor that is further reduced in weight, size, and cost can be obtained.
[0044]
  Further, by integrally forming the main magnetic pole portion 6 and the sensor magnetic pole portion 21a with the thermoplastic resin 24 interposed therebetween, the parallelism and surface roughness of the axial end surfaces of the main magnetic pole portion 6 and the sensor magnetic pole portion 21a are formed. Since there is no need to increase the accuracy of the perpendicularity to the magnetic pole surface, there is no need to increase the accuracy of the magnet mold and end face polishing, the cost can be reduced, and a lower-cost brushless motor can be obtained.
[0045]
【The invention's effect】
  As is clear from the above embodiments, according to the present invention, the main magnetic pole portion is formed of a sintered ferrite polar anisotropic magnet and the sensor magnetic pole portion is an isotropic resin smaller than the outer diameter of the main magnetic pole portion. A magnet or an isotropic rubber magnet, the main magnetic pole part and the sensor magnetic pole part are positioned side by side in the axial direction, and the protrusion that fixes the sensor magnetic pole part to the holding part that holds the main magnetic pole part on the shaft The sensor magnetic pole part is provided with a fixing through hole, the through hole is fitted into the protrusion, and the tip part of the protrusion is crushed to fix the sensor magnetic pole part. As a result, it is possible to reduce the magnet volume, such as shortening the axial length of the main magnetic pole part while securing an appropriate flux linkage, and the magnetic center of the main magnetic pole part that generates rotational torque and the magnetic center of the main magnetic pole part. Therefore, the occurrence of vibration in the axial direction can be suppressed. In addition, since magnetic saturation is suppressed and the linkage flux becomes a sine wave, operation can always be performed with the optimum energization phase with respect to the induced voltage phase, so an increase in torque ripple and torque change rate is suppressed, and vibration in the rotational direction is suppressed. Increase is suppressed. In addition, the magnet volume can be reduced, and accurate alignment of the sensor magnetic pole part with respect to the main magnetic pole part can be facilitated, so the number of processing steps for manufacturing the magnet rotor can be reduced, and weight imbalance and sensor signal imbalance can be reduced. Uniformity can be suppressed. In addition, the man-hours, processing costs, and investment costs for manufacturing the magnet rotor can be reduced, and since the magnet rotor can be manufactured in two steps, the production tact time is shortened, the production capacity is increased, and the cost is reduced. Therefore, cost reduction, size reduction, and weight reduction can be achieved. Therefore, a low-cost brushless motor with low cost, low vibration, small size, and light weight can be obtained.
[0046]
  Also, the small diameter side of the stepped through hole or mortar-shaped through hole is positioned on the main magnetic pole part side and fitted into the protrusion, and the tip of the protrusion is the large diameter part space of the stepped through hole or mortar-shaped through hole The axial length of the magnet part of the magnet rotor can be shortened by crushing inward and fixing the magnetic pole part for the sensor, so the printed circuit board can be brought closer to the magnet part and the axial length of the brushless motor Therefore, a brushless motor with further reduced weight, size and cost can be obtained.
[0047]
  Also, by forming the tip of the protrusion with a thin wall, the tip can be easily crushed and the processing time is shortened, so the production tact is shortened, the production capacity is increased, and the cost can be reduced. Therefore, a lower-cost brushless motor can be obtained.
[Brief description of the drawings]
FIG. 1 of the present inventionreferenceLongitudinal sectional view showing the structure of the brushless motor in Example 1
FIG. 2 is a longitudinal sectional view of a magnet rotor of the brushless motor.
FIG. 3 shows an embodiment of the present invention.1Sectional view showing the structure of a brushless motor
FIG. 4 is a perspective view of a magnetic pole portion for a sensor of the same brushless motor.
FIG. 5 is a perspective view of the magnet rotor before the sensor magnetic pole part of the brushless motor is mounted.
FIG. 6A is another perspective view of the magnet rotor before attaching the magnetic pole part for sensor of the same brushless motor.
  (B) The other perspective view in the magnet rotor before attaching the magnetic pole part for sensors of the same brushless motor.
FIG. 7A is a perspective view of another sensor magnetic pole portion in the same brushless motor.
  (B) Sectional view of another sensor magnetic pole part in the same brushless motor
FIG. 8 is a cross-sectional view of another sensor magnetic pole part in the same brushless motor.
FIG. 9 is a longitudinal sectional view of another magnet rotor in the same brushless motor.
FIG. 10 is a longitudinal sectional view showing another structure of the brushless motor.
FIG. 11 shows the present invention.Reference example 2Sectional view of the magnet rotor of a brushless motor
FIG. 12 is a longitudinal sectional view showing the structure of a conventional brushless motor
FIG. 13 is an exploded perspective view showing a stator, a magnet rotor, and a printed circuit board of the same brushless motor.
[Explanation of symbols]
1 Stator
2 Insulator
3 Armature winding
4 Stator core
5 Thermoplastic resin
5a gap
6 Main magnetic pole
6a Sensor magnetic pole part side axial end face
7 Magnetic pole for sensor
8 Magnet rotor
9 Shaft
10 Printed circuit board
11 Hall IC
12 Driving IC
12a Connecting leg
12b Solder part
13 Electronic components
13a Electronic component having a height of 2 mm or more
14 Bearing
15 Space
16 Thermosetting resin
17 Bracket
18 Magnet rotor
18a Magnet rotor
19 Holding part
19a Axial end face of sensor magnetic pole side
20 protrusions
20a Tip
20b Tip
21 Magnetic pole for sensor
21a Magnetic pole for sensor
22 Through hole
22a Stepped through hole
22b Large diameter space
22c Mortar-shaped through hole
23 Magnet rotor
24 Thermoplastic resin

Claims (3)

A brushless motor with a built-in stator in which an armature winding is wound around a stator core, a magnet rotor using polar anisotropic magnets, and a printed circuit board on which electronic components such as a Hall IC are mounted. The magnet rotor includes an annular main magnetic pole portion made of a sintered polar anisotropic magnet, and a fixing through-hole made of a substantially annular resin magnet or rubber magnet having an outer diameter smaller than the outer diameter of the main magnetic pole portion. The main magnetic pole portion is fixed to the shaft through a holding portion, and the holding portion has a protrusion for fixing the sensor magnetic pole portion, and the protrusion is provided with the sensor magnetic pole portion. A brushless motor , wherein a through hole of a magnetic pole portion is fitted, and the tip portion of the protrusion is crushed to fix the sensor magnetic pole portion . The through hole provided in the magnetic pole part for the sensor is a stepped through hole or a mortar-like through hole, and the small diameter side of the through hole is positioned on the main magnetic pole part side in the protrusion provided in the holding part. 2. The sensor magnetic pole part according to claim 1, wherein the sensor magnetic pole part is fixed by crushing and fitting the tip part of the protrusion into the large-diameter space of the stepped through hole or mortar-like through hole. Brush motor. The brushless motor according to claim 1, wherein at least a tip portion of the protrusion provided on the holding portion is thin.

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