JP2009303417A - Motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem, wherein a magnetic path space is narrowed by the notched section of an adhesive surface in a laminated core for a brushless motor, a torque is lowered and a torque ripple is caused. <P>SOLUTION: The brushless motor 100 contains the laminated core 150, a motor base 110, a rotor 120 and a bearing unit 130. Adhesive reservoirs 156 are formed to the inner peripheral surface of the laminated core 150, at the same angular positions as the angles formed to salient poles 154 from a rotating shaft for the motor. A small amount of adhesive is held to the adhesive reservoirs 156, when the laminated core 150 and the motor base 110 are bonded and fixed. The adhesive reservoirs 156 are formed extensively over five steel sheets from the top face of the laminated core 150. The adhesive reservoirs 156 are formed, by notching in a semicircular shape toward the outside-diameter side of the laminated core 150. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a motor, and more particularly to a structure of a laminated core used in a motor.

  In order to converge the magnetic flux, a brushless motor mounted on a hard disk drive that drives a magnetic recording disk, or a disk drive motor mounted on an optical disk drive such as a CD (Compact Disc) device or a DVD (Digital Versatile Disc) device. A laminated core is used. A typical laminated core has an annular portion serving as a magnetic path and a plurality of salient poles extending radially outward therefrom. This laminated core is produced by laminating a plurality of non-oriented electrical steel sheets. In order to fix the laminated core to the motor base, the annular portion is fitted into the motor base and bonded.

Here, in order to ensure sufficient adhesive strength, a cutout portion cut out in the radial direction is provided over the entire thickness of the laminated core on the bonding surface of the annular portion. The adhesive strength can be improved and stabilized by accumulating an adhesive in the notch.
JP 63-217964 A JP-A-5-83889 JP-A-8-116656 Japanese Patent Laid-Open No. 8-11949 JP-A-9-294347 JP 2000-270505 A JP 2001-057747 A JP 2001-320842 A Japanese Patent Laid-Open No. 2004-23848 JP 2006-129583 A JP 2006-158056 A JP 2006-136090 A

  About such a brushless motor and its laminated core, this inventor recognized the following subjects. In recent years, miniaturization of hard disk drives has progressed, and along with this, there has been an increasing demand for miniaturization of brushless motors. Therefore, there is a great need for smaller laminated cores. Here, considering the miniaturization of the laminated core, the size of the bearing that fits inside the annular portion is determined, so there is a limit to reducing the inner diameter of the laminated core. It is also difficult to reduce the length of the salient poles in order to secure the space for the winding. Accordingly, the laminated core can be reduced in size by reducing the annular portion.

  However, when the annular portion is made thinner, the width of the annular portion is further narrowed particularly in the periphery where the above-described notch portion is provided, and the area (magnetic path space) through which the magnetic flux flows becomes smaller. Then, this may become a bottleneck, and it may be difficult for a sufficient magnetic flux to flow in the laminated core, and the necessary torque may not be obtained.

  This invention is made | formed in view of such a condition, The objective is to provide a brushless motor provided with the lamination | stacking core which improved the flow of magnetic flux.

  One embodiment of the present invention relates to a motor. This motor is integrally formed by laminating a rotor, a bearing unit that rotatably supports the rotor, a base member that holds the bearing unit, and n (n is an integer of 2 or more) steel plates. And a plurality of salient poles extending radially outward from the core, fixed to the base member using an adhesive, and wound around at least one of the salient poles And a magnet that is opposed to the plurality of salient poles in the radial direction and includes drive magnetization, and a rotor yoke that is provided on the rotor and holds the magnet. An adhesive filling groove provided by a notch toward the outer diameter side of the core on the side surface that defines the inner diameter of the core is placed on one surface of the core at an angular position where salient poles are formed with respect to the angle with respect to the annular portion. To (n-1) or less steel sheets.

  Another embodiment of the present invention is also a motor. This motor is integrally formed by laminating a rotor, a bearing unit that rotatably supports the rotor, a base member that holds the bearing unit, and n (n is an integer of 2 or more) steel plates. And a plurality of salient poles extending inward in the radial direction from the core, fixed to the base member using an adhesive, and wound around at least one of the salient poles And a magnet that is opposed to the plurality of salient poles in the radial direction and includes drive magnetization, and a rotor yoke that is provided on the rotor and holds the magnet. An adhesive filling groove provided by a notch toward the inner diameter side of the core on a side surface that defines the outer diameter of the core is placed on one surface of the core at an angular position where salient poles are formed with respect to the angle with respect to the annular portion. To (n-1) or less steel sheets.

  According to these embodiments, the adhesive filling groove is continuously formed from one surface of the core to a plurality of (n−1) or less steel plates. Therefore, since the groove does not penetrate the core in the thickness direction, the magnetic path space at the base of the salient pole can be increased.

  Note that any combination of the above-described constituent elements, and those obtained by replacing the constituent elements and expressions of the present invention with each other among methods, apparatuses, systems, etc. are also effective as an aspect of the present invention.

  With the motor according to the present invention, the flow of magnetic flux in the laminated core can be improved.

  The embodiment of the present invention is suitably used for a brushless motor that is mounted on a hard disk drive and drives a magnetic recording disk, and a disk drive motor that is mounted on an optical disk drive device such as a CD device or a DVD device. Furthermore, it is also suitably used for a motor that rotationally drives a polygon mirror in a laser beam printer.

  In the following, the same or equivalent components and members shown in each drawing will be denoted by the same reference numerals, and repeated description will be omitted as appropriate. In addition, the dimensions of the members in each drawing are appropriately enlarged or reduced for easy understanding. In the drawings, some of the members that are not important for describing the embodiment of the present invention are omitted.

(First embodiment)
FIG. 1 is a cross-sectional view of a brushless motor 100 according to the first embodiment. FIG. 2 is an enlarged view of a contact portion between the laminated core 150 and the motor base 110 in FIG. The brushless motor 100 includes a laminated core 150, a motor base 110, a rotor 120, and a bearing unit 130. The brushless motor 100 is a spindle motor that is driven by a drive current composed of three phases of U phase, V phase, and W phase, which are shifted from each other by 120 degrees in electrical angle. The motor base 110 forms part of a base plate of a hard disk drive in which the brushless motor 100 is incorporated. Hereinafter, the surface of the motor base 110 on which the laminated core 150 is mounted is referred to as the upper surface. A cylindrical portion concentric with the motor rotation shaft protrudes from the upper surface of the motor base 110, and a bearing holding hole 112 which is a through hole concentric with the motor rotation shaft is provided in the cylindrical portion. Referring to FIG. 2, a step for holding the laminated core 150 is formed on the outer peripheral surface of the cylindrical portion. The cylindrical side surface of the step is referred to as a guide surface 110A, and the stepped step surface is referred to as a stopper surface 110B. Returning to FIG. The motor base 110 is provided with a wiring through-hole 114 for drawing the drive lead 142 to the lower surface side of the motor base 110.

  The rotor 120 includes a hub 121, a shaft 122, a flange 123, an annular yoke 124, and an annular magnet 125, and these rotate together as the brushless motor 100 rotates. A magnetic recording disk is attached to the outer peripheral surface 121 </ b> A of the hub 121. The hub 121 is made of a lightweight material such as aluminum. The outer diameter of the hub 121 is 19.95 mm. One end of the shaft 122 is fixed in a press-fitted state to an opening 121 </ b> B provided in the center of the hub 121. A flange 123 is fixed to the other end of the shaft 122 in a press-fit state. The shaft 122 and the flange 123 are made of a highly rigid metal such as stainless steel.

  An annular magnet 125 is bonded and fixed to the inner peripheral surface of the annular yoke 124. The annular yoke 124 is bonded and fixed to the lower surface of the hub 121. The annular magnet 125 is magnetized for driving with 8 poles in the circumferential direction. The annular yoke 124 is formed of a magnetic material such as iron.

The bearing unit 130 includes a bearing 131 and a seal plate 132. A bearing 131 is inserted into the above-described bearing holding hole 112 and fixed by adhesion. The above-described shaft 122 is accommodated in the bearing 131. A seal plate 132 is bonded and fixed to the surface of the bearing 131 on the flange 123 side and sealed. The bearing 131 is made of a metal that can be easily processed, such as brass. The seal plate 132 is made of a highly rigid metal such as stainless steel. The outer diameter of the bearing 131 is 7.3 mm.
Lubricating oil is injected between the shaft 122 and the flange 123 which are a part of the rotor, and the bearing 131 and the seal plate 132 which are members fixed to the motor base 110.

  The laminated core 150 has an annular portion 152 and twelve salient poles 154 extending radially outward therefrom. The twelve salient poles 154 are arranged at equal intervals in the circumferential direction. That is, the angle between adjacent salient poles as viewed from the central axis of the annular portion 152 is 30 degrees. The laminated core 150 is formed by laminating 10 thin electromagnetic steel plates having the same thickness and integrating them by laser welding. The cross section of the laminated core 150 shown in FIG. 1 is a cross section of a portion corresponding to the salient pole 154 on both the left and right sides. The laminated core 150 has an outer diameter of 15.8 mm, an inner diameter of 8.95 mm, and a thickness of 2.0 mm. The width of the annular portion 152 is 1.3 mm. A coil 160 is wound around each salient pole 154 of the laminated core 150. When a drive current flows through the coil 160, a drive magnetic flux is generated along the salient pole 154.

  The laminated core 150 is attached to the motor base 110 by adhesive fixing by clearance fit fitting. Referring to FIG. 2, more specifically, in a state where inner peripheral surface 150A of laminated core 150 has a slight gap with respect to guide surface 110A, laminated core 150 is laminated until the lower surface of laminated core 150 contacts stopper surface 110B. 150 is fitted. The gap is then at least partially filled with an adhesive.

An adhesive reservoir 156 is formed on the inner peripheral surface 150 </ b> A of the laminated core 150 at the same angular position as the angle corresponding to the center of the salient pole 154 when viewed from the central axis of the annular portion 152. When the laminated core 150 and the motor base 110 are bonded and fixed, a small amount of adhesive is held in the adhesive reservoir 156.
The adhesive reservoir 156 is continuously formed from the upper surface of the laminated core 150 to five steel plates. Therefore, the adhesive reservoir 156 is blocked on the lower surface of the laminated core 150, that is, the surface on the motor base 110 side. Therefore, most of the adhesive remains in the adhesive reservoir 156 during the process of bonding the laminated core 150 to the motor base 110. As a result, the flow of adhesive to the motor base 110 can be reduced, and the adhesive strength is further increased.
Further, since the adhesive reservoir 156 is opened to the outside from the upper surface of the laminated core 150, it serves as an air vent during bonding. Also, excess adhesive overflowing from the adhesive reservoir 156 can be easily removed. This can reduce the amount of the adhesive that remains uncured even after the adhesive curing process. This contributes to an increase in adhesive strength and reduces outgas from the uncured adhesive, which is advantageous from the viewpoint of long-term reliability.

  The adhesive reservoir 156 is formed by cutting out into a semicircular shape having a diameter of 0.6 mm toward the outer diameter side of the laminated core 150. As this forming method, for example, notches may be provided in each steel plate before lamination, and the steel plates may be integrally joined with the positions of the notches being aligned. In this case, the shape of the notch can be made with high accuracy. Further, the adhesive reservoir 156 may be integrally formed by notching means such as end milling. In this case, the manufacturing process of the laminated core is shortened, which contributes to the improvement of productivity.

  Returning to FIG. The coil 160 is connected to the control board of the hard disk drive through the drive lead 142 and the flexible board 148. The flexible substrate 148 is bent and attached to the lower surface of the motor base 110. One end of the drive lead 142 is connected to the coil 160. The drive conducting wire 142 is drawn to the lower surface side of the motor base 110 through the wiring through hole 114 and connected to the flexible substrate 148. The wiring through-hole 114 is sealed with a sealing resin 144 such as an epoxy thermosetting resin. In order to protect the contact between the drive lead 142 and the flexible substrate 148 from an electrical contact from the outside, an insulating resin 146 such as an acrylic ultraviolet curable resin is applied so as to cover the contact.

  FIG. 3 is a top view of the laminated core 150 of FIG. A line segment AA corresponds to the cross section of FIG. A coil 160 (not shown in FIG. 3) is wound around each salient pole 154, and a drive current corresponding to one of the three phases flows through the coil 160. Of the 12 salient poles 154, the salient pole corresponding to the U phase is the U phase salient pole 154U, the salient pole corresponding to the V phase is the V phase salient pole 154V, and the salient pole corresponding to the W phase is the W phase salient pole 154W. I will call it. In the laminated core 150, a U-phase salient pole 154U, a V-phase salient pole 154V, and a W-phase salient pole 154W are repeatedly arranged in this order in the circumferential direction.

  Regarding the arrangement of the adhesive reservoir 156, the adhesive reservoir 156 is provided at the base of a certain salient pole, and the salient pole root located at an angle of +120 degrees with respect to the salient pole as viewed from the central axis of the annular portion 152. And is further provided at the base of the salient pole at an angular position of -120 degrees. In this case, due to the symmetry of the salient pole arrangement, one adhesive reservoir 156 is provided for each of the U phase, the V phase, and the W phase. In this arrangement, the adhesive reservoirs 156 are provided at equal intervals on the inner periphery of the laminated core 150, so that a mechanical balance is achieved. Therefore, strong adhesion is realized against impacts from any direction.

  The operation of the brushless motor 100 configured as described above will be described. In order to rotate the brushless motor 100, a three-phase driving current is supplied to the brushless motor 100 through the flexible substrate 148. When the drive current flows through the coil 160, a drive magnetic flux is generated along the salient pole 154. At that time, in the brushless motor 100 according to the present embodiment, although the adhesive reservoir 156 is provided at the base of the salient pole 154 of the laminated core 150, it does not penetrate the laminated core 150 in the thickness direction. There is a portion that is not narrowed by the adhesive reservoir 156 at the base of the salient pole 154. Therefore, the magnetic path space at the base of the salient pole 154 is relatively wide while maintaining the adhesive strength, and a sufficient magnetic flux flows in the laminated core 150 to obtain a necessary torque.

  As described above, according to the brushless motor 100 according to the present embodiment, the magnetic path space at the base of the salient pole is larger than the conventional configuration in which the notch portion is provided to penetrate from the upper surface to the lower surface of the laminated core. Can take. Therefore, the flow of magnetic flux when converging the magnetic flux on the salient pole is improved, and the torque performance of the brushless motor 100 is improved. Moreover, torque ripple is reduced by reducing local magnetic loss. Thereby, a small and low vibration brushless motor is realized.

FIGS. 4A to 4B are graphs showing experimental results of measuring the adhesive strength and the magnetic saturation ratio with respect to the number of steel plates provided with notches in the laminated core 150.
FIG. 4A is a graph showing experimental results of measuring the adhesive strength with respect to the number of steel plates provided with notches in a laminated core 150 in which 10 steel plates are laminated. The horizontal axis indicates the number of steel plates provided with notches, and the vertical axis indicates the adhesive strength in N (Newton) units. Here, the adhesive strength is the adhesive strength of the laminated core 150 to the motor base 110. The diamond-shaped black dots in FIG. 4A are measured data points. A solid line is a fitting curve obtained by fitting data points. It is considered that a laminated core formed by laminating 10 steel plates has practical adhesive strength if it has an adhesive strength of 460 N or more as a design experience value. Therefore, it can be seen from this experimental result that three or more steel plates with notches are required in order to maintain practical adhesive strength.

FIG. 4B is a graph showing experimental results obtained by measuring the magnetic saturation ratio with respect to the number of steel plates provided with notches in a laminated core 150 in which 10 steel plates are laminated. The horizontal axis indicates the number of steel plates provided with notches, and the vertical axis indicates the magnetic saturation rate in%. The diamond-shaped black dots in FIG. 4 (b) are measured data points. A solid line is a fitting curve obtained by fitting data points. If the magnetic saturation rate is 92% or less as an empirical value in design, it is considered that the magnetic saturation rate is practical. Therefore, it can be seen from this experimental result that the number of notched steel plates needs to be 8 or less in order to maintain a practical magnetic saturation rate.
From the above experimental results, if the length of the adhesive reservoir 156 is 30% or more and 80% or less of the thickness of the laminated core 150, the magnetic saturation can be suppressed to a practical value while maintaining sufficient adhesive strength. It turns out that it is.

In the first embodiment, the adhesive reservoir 156 is provided at the base of a salient pole, and is provided at the base of the salient pole at an angle position of +120 degrees with respect to the salient pole as viewed from the central axis of the annular portion 152. Furthermore, although the case where it is provided at the base of the salient pole at an angular position of −120 degrees has been described, the arrangement of the adhesive reservoir 156 is not limited to this, and various modifications are possible.
FIGS. 5A and 5B are top views showing modifications of the laminated core 150. FIG.
FIG. 5A is a top view showing a laminated core 170a according to a first modification. The difference between the laminated core 150 according to the first embodiment and the laminated core 170a according to the first modification is in the position of the adhesive reservoir 156. In the laminated core 170a, the adhesive reservoir 156 is provided at the base of a certain salient pole, and is provided at the base of the salient pole at an angular position of +150 degrees with respect to the salient pole as viewed from the central axis of the annular portion 152. It is provided at the base of the salient pole at an angular position of −150 degrees. In this case, due to the symmetry of the salient pole arrangement, one adhesive reservoir 156 is provided for each of the U phase, the V phase, and the W phase.

  FIG. 5B is a top view showing a laminated core 170b according to a second modification. The difference between the laminated core 150 according to the first embodiment and the laminated core 170b according to the second modification is in the position of the adhesive reservoir 156. In the laminated core 170b, the adhesive reservoir 156 is provided at the base of three continuous salient poles. Therefore, one adhesive reservoir 156 is provided for each of the U phase, the V phase, and the W phase.

  More generally, the adhesive reservoir 156 is evenly arranged for each phase of the drive current. That is, a total of three U phases, V phases, and W phases are provided, one for each phase. In other words, the adhesive reservoir 156 is provided at an electrical angle of 120 degrees. Thereby, the amount of magnetic flux is balanced between the phases of the drive current, and vibration of the brushless motor can be suppressed. Furthermore, since there are various variations in the arrangement of the adhesive reservoir 156, a flexible design that matches the structure and application of the brushless motor is possible.

(Second Embodiment)
FIG. 6 is a cross-sectional view of a brushless motor 200 according to the second embodiment. The biggest difference from the first embodiment is the shape of the contact portion between the lower surface of the core 250 and the base member 210. The motor according to the present embodiment includes a rotor 120, a bearing unit 130 that rotatably supports the rotor 120, a base member 210 that holds the bearing unit 130, and n (n is an integer of 2 or more) steel plates. A core 250 that is integrally formed by stacking and includes an annular portion 252 and a plurality of salient poles 254 extending radially outward therefrom, and is fixed to the base member 210 using an adhesive, and a plurality of salient poles A coil 160 wound around at least one of the salient poles 254, a circular magnet 125 that is opposed to the plurality of salient poles 254 in the radial direction and includes drive magnetization, and the rotor 120. An annular yoke 124 for holding the annular magnet 125, and an adhesive provided on a side surface defining the inner diameter of the core 250 by a notch toward the outer diameter side of the core 250. The filling groove 256 is continuously extended from one surface of the core 250 to a plurality of (n−1) or less steel plates at an angular position where the salient pole 254 is formed with respect to the angle with respect to the annular portion 252. A protrusion 258 is provided on the surface of the core 250 on the base member 210 side, and the core 250 side surface of the base member 210 has a structure that fits with the protrusion 258.

The protrusion 258 is a protruding edge provided on the annular portion 252 side of the steel plate facing the base member 210 among the steel plates included in the core 250. A concave portion 216 corresponding to the protruding edge is provided on the surface of the base member 210 on the core 250 side, and the protruding edge is fitted into the recessed portion 216 by fitting means such as press fitting or gap fitting.
The base member 210 is made of a nonmagnetic metal such as aluminum. The steel plate included in the core 250 is a steel plate formed of a magnetic metal having a lower thermal expansion coefficient than the above-described nonmagnetic metal, such as a silicon steel plate. Therefore, at a temperature lower than the room temperature at the time of assembling the brushless motor, the base member 210 shrinks at a larger rate than the core 250. In this case, the outer periphery of the protrusion 258 is held by the recess 216, and the fixing strength can be kept high even at a low temperature. As a result, the operating temperature range of the brushless motor is expanded.

  The operation of the brushless motor 200 configured as described above will be described. Similar to the brushless motor 100 according to the first embodiment, a drive current is supplied to the brushless motor 200, and a drive magnetic flux is generated along the salient pole 254. At that time, in the brushless motor 200 according to the second embodiment, although the adhesive filling groove 256 is provided at the base of the salient pole 254 of the core 250, it penetrates the core 250 in the thickness direction. Therefore, there is a portion that is not narrowed by the adhesive filling groove 256 at the base of the salient pole 254. Therefore, the magnetic path space at the base of the salient pole 254 is relatively wide while maintaining the bonding strength, and a sufficient magnetic flux flows in the core 250 to obtain a necessary torque. Furthermore, the strength of fixing the core 250 to the base member 210 can be increased by fitting the protrusion 258 into the recess 216.

  The configuration and operation of the brushless motor according to the embodiment have been described above. It is to be understood by those skilled in the art that these embodiments are exemplifications, and that various modifications can be made to combinations of the respective components, and such modifications are within the scope of the present invention.

  In the embodiment, the case where all the three adhesive reservoirs 156 are continuously formed from the upper surface of the laminated core 150 to the five steel plates has been described. However, the lengths of the adhesive reservoirs 156 may be different from each other. . However, in order to improve the symmetry of the magnetic flux between the phases of the drive current, it is desirable to provide the laminated core 150 with an adhesive reservoir 156 having an equal length.

  In the embodiment, the description has been given of the three-phase brushless motor 100 including the annular magnet 125 that is magnetized for driving with 8 poles and the laminated core 150 having 12 salient poles. A three-phase brushless motor may be provided that includes a magnet magnetized for driving and a core having nine salient poles. More generally, k and m are natural numbers, a magnet having k poles for driving magnetization, and a core including m salient poles, and k: m is 2: 3. A characteristic three-phase brushless motor may be used. In this case, an equal number of salient poles can be assigned to each phase, and symmetry is increased. In particular, the core including the m salient poles described above is a core in which salient poles corresponding to the U phase, the V phase, and the W phase appear at equal intervals in the circumferential direction of the core, and m is not a multiple of 9. This may be a feature. In this configuration, a total of three grooves for filling the adhesive provided at the base of the salient poles, one for each phase, can be arranged at intervals of 120 degrees when viewed from the central axis of the core. In this way, the grooves for filling the adhesive are arranged in a mechanically balanced manner, which contributes to the realization of strong adhesion against impacts from any direction.

  In the embodiment, a case has been described in which a total of three adhesive reservoirs 156 are provided in the laminated core 150, one for each of the U phase, the V phase, and the W phase. For example, the adhesive reservoirs are U phase, V phase, and W phase. There may be a total of six, two for each. More generally, p is a natural number, q is a natural number of 3 or more, and (p × q) is less than or equal to the number of salient poles. Xq) Adhesive reservoirs may be provided. In this case, a brushless motor having a laminated core with high magnetic symmetry while maintaining adhesive strength is realized.

In the embodiment, the case where the adhesive reservoir 156 is formed by being cut out in a semicircular shape toward the outer diameter side of the laminated core 150 has been described, but there are various modified examples of the shape of the cutout. Is possible. FIGS. 7A to 7C are top views showing a laminated core according to a modified example of a notch shape. In FIG. 7A, the adhesive reservoir 182a is formed by cutting out in a wedge shape toward the outer diameter side of the laminated core 180a. In this case, the magnetic path space at the base of the salient pole becomes wider because the notch has no swelling. Further, the angle θ formed by the wedge may be an obtuse angle. In this case, the area of the adhesive surface between the adhesive reservoir 182a and the motor base is increased, which contributes to the improvement of the adhesive strength.
In FIG. 7B, the adhesive reservoir 182b is formed by cutting out in a wedge shape toward the outer diameter side of the laminated core 180b, and each of the two sides forming the wedge is bonded to the adhesive reservoir 182b. It has a shape bent to the side. In this case, the area of the adhesive surface between the adhesive reservoir 182b and the motor base is increased, which contributes to the improvement of the adhesive strength.
In FIG. 7C, the adhesive reservoir 182c is formed by cutting out into a rectangular shape toward the outer diameter side of the laminated core 180c. In this case, since the adhesive pool 182c is less likely to enter the annular portion of the laminated core 180c while taking a wide adhesive surface, the magnetic path space can be made wider.

  Although the laminated core 150 including the annular portion 152 and the plurality of salient poles 154 extending radially outward therefrom has been described in the embodiment, the laminated core including the annular portion and the plurality of salient poles extending radially inward therefrom. It may be. In this case, the adhesive reservoir is provided on the outer peripheral surface of the laminated core.

  In the embodiment, the case where the bearing 131 is fixed to the motor base 110 and the shaft 122 rotates relative to the bearing 131 has been described. For example, the shaft is fixed to the motor base, and the bearing rotates relative to the shaft together with the hub. May be.

  In the embodiment, the case where the motor base 110 forms part of the base plate has been described. However, for example, the motor base may be a motor base of a brushless motor alone.

  In the embodiment, the case where the steel plates are integrally formed by laser welding has been described. However, for example, they may be integrally formed by caulking.

  Although the present invention has been described based on the embodiments, the embodiments merely show the principle and application of the present invention, and the embodiments are defined in the claims. Needless to say, many modifications and arrangements can be made without departing from the spirit of the present invention.

It is sectional drawing of the brushless motor which concerns on 1st Embodiment. It is an enlarged view of the contact part of the lamination | stacking core of FIG. 1, and a motor base. It is a top view of the laminated core of FIG. 4 (a) to 4 (b) are graphs showing experimental results of measuring the adhesive strength and magnetic saturation with respect to the number of steel plates provided with notches in the laminated core. FIGS. 5A to 5B are top views showing modifications of the laminated core. It is sectional drawing of the brushless motor which concerns on 2nd Embodiment. FIGS. 7A to 7C are top views showing a laminated core according to a modified example of a notch shape.

Explanation of symbols

  100 brushless motor, 110 motor base, 120 rotor, 130 bearing unit, 150 laminated core, 152 annular portion, 154 salient pole, 156 adhesive reservoir, 160 coil, 200 brushless motor, 216 recess, 258 projection.

Claims (4)

A rotor,
A bearing unit for rotatably supporting the rotor;
A base member for holding the bearing unit;
n (n is an integer greater than or equal to 2) steel plates are integrally formed, and include an annular portion and a plurality of salient poles extending radially outward therefrom, and using an adhesive to the base member A fixed core,
A coil formed by winding around at least one of the plurality of salient poles;
A magnet that opposes the plurality of salient poles in a radial direction and includes magnetization for driving;
A rotor yoke provided on the rotor and holding the magnet;
On the side surface defining the inner diameter of the core, the groove for filling the adhesive provided by a notch toward the outer diameter side of the core is at an angular position where the salient pole is formed with respect to the angle with respect to the annular portion. A motor formed continuously from one surface of the core to a plurality of (n-1) or less steel plates.   The motor according to claim 1, wherein a length of the groove is 30% or more and 80% or less of a thickness of the core. A rotor,
A bearing unit for rotatably supporting the rotor;
A base member for holding the bearing unit;
n (n is an integer greater than or equal to 2) steel plates are integrally formed, including an annular portion and a plurality of salient poles extending radially inward therefrom, and using an adhesive to the base member A fixed core,
A coil formed by winding around at least one of the plurality of salient poles;
A magnet that opposes the plurality of salient poles in a radial direction and includes magnetization for driving;
A rotor yoke provided on the rotor and holding the magnet;
On the side surface defining the outer diameter of the core, the adhesive filling groove provided by a notch toward the inner diameter side of the core is at an angular position where the salient pole is formed with respect to the angle with respect to the annular portion. A motor formed continuously from one surface of the core to a plurality of (n-1) or less steel plates.   The motor according to claim 3, wherein a length of the groove is 30% or more and 80% or less of a thickness of the core.

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