JP2008172922A - Radial gap type dc brushless motor and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce vibration and noise of a radial gap type DC brushless motor by stabilizing the allotment position of divided type salient poles and suppressing torque ripples. <P>SOLUTION: A salient pole sub-assembly 3 configures to that a plurality of salient poles 4 are radially disposed and internally molded with a resin 5 uniformly stabilizes the allotment positions of the salient poles by the salient poles 4 themselves (autonomously), irrespective of the plurality of salient poles 4 have a divided structure. The salient sub-assembly 3 is molded with resin in a state where the salient poles 4 are each correctly positioned using a die while using the predetermined inner dimension as a reference, and thus, the positional accuracy of each of the salient poles 4 can be improved. As this result, the torque ripples of the DC brushless motor can be suppressed to reduce the vibration and noise. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a DC brushless motor, and more particularly to an inner rotor type radial gap type DC brushless motor having a plurality of divided salient poles.

  Conventionally, there has been known a DC brushless motor having an armature structure in which a plurality of salient poles are formed radially from a flat ring-shaped yoke made of a soft magnetic plate material such as a silicon steel plate and are laminated in the axial direction. Yes. In the manufacturing process of the DC brushless motor, the flat ring-shaped yoke is integrally pressed with a plurality of salient poles, so that the salient poles are not divided, and the magnetic force during motor operation is reduced. There is an advantage that it is excellent in efficiency.

However, in the case of a small DC brushless motor, since the coil winding is generally wound directly on each salient pole, the winding work on each salient pole is complicated, and in particular, the inner rotor type motor In this case, winding work becomes very difficult. As a result, there are problems that it takes time for the winding work process and it is difficult to increase the space factor of the winding. For this reason, the salient pole part of the flat ring-shaped yoke is divided, and a stator is constructed by attaching a bobbin around which the coil is wound to each divided salient pole, and this stator is fixed in a metallic case and assembled. A DC brushless motor having a split type salient pole structure is proposed (for example, Patent Document 1).
In addition, a plurality of divided salient poles and a ring that magnetically and mechanically couples these salient poles are used, and the ring is provided with slits for attaching salient poles to reduce workability and magnetic resistance during assembly. There has been proposed a DC brushless motor having a divided salient pole structure having the above-described configuration (for example, Patent Document 2).

7 is a sectional view in the axial direction of the radial gap type DC brushless motor described in Patent Document 1, FIG. 8 is a partially exploded perspective view of the DC brushless motor shown in FIG. 7, and FIG. The bobbin mounting state of the DC brushless motor shown in FIG. 7 is shown.
A radial gap type DC brushless motor 100 described in Patent Document 1 is made of a resin in which a plurality of electromagnetic steel sheets punched into a substantially T-shape are stacked and then caulked to form salient poles 134 and coils 138 are wound. The protrusion 135 of the salient pole 134 is inserted into the hole of the bobbin 136. The salient poles 134 to which the bobbins 136 are attached are respectively attached to predetermined positions inside the metal case 104. The inner diameter portion of the case 104 is filled with the resin 158 leaving a space where the rotor 110 is inserted from the resin injection hole 137. At this time, as shown in FIG. 8, the bearing housing 114 and the boss 119 are simultaneously formed on one end side of the case 104 by the injected resin 158, and the bearing 120 is mounted on the bearing housing 114.

  10 is a sectional view in the axial direction of the radial gap type DC brushless motor described in Patent Document 2, and FIG. 11 is a view showing a bobbin mounted state of the DC brushless motor shown in FIG. Is an exploded perspective view of the armature assembly of the DC brushless motor shown in FIG.

  Similarly to Patent Document 1, the radial gap type DC brushless motor 200 described in Patent Document 2 is formed by laminating a plurality of electromagnetic steel plates punched into a substantially T shape, and then caulking to form salient poles 234, and a coil 238. The salient pole protrusion 235 is inserted into the hole of the resin bobbin 236 around which the wire is wound. Then, the protrusions 235 formed on the respective salient poles 234 are respectively inserted into the axial slits 251 of the pole tooth rings 250 to mount the salient poles 234, and then the pole tooth rings 250 are attached to the inner side of the stator ring 300 to form the armature assembly. Form a solid. Next, the resin 258 is injected into the inner diameter portion of the pole tooth ring 250 from the resin injection hole 237, and the resin 258 is placed between the salient pole assembly and the pole tooth ring 250, leaving a space portion in which the rotor 210 is inserted. Filled. At this time, similarly to Patent Document 1, the bearing housing 214 and the boss portion 219 are simultaneously formed on one end side of the stator ring 300 by the injected resin 258, and the bearing 220 is mounted on the bearing housing 214.

JP 2000-060053 A JP 2001-238377 A

However, the DC brushless motor having a split salient pole structure of the above-described conventional configuration has a bobbin in which a coil is wound around the salient pole in the manufacturing process, and the salient pole on which the bobbin is attached is a pole tooth. After being attached to the ring and inserting this pole tooth ring inside the stator ring, the resin is filled into the pole tooth ring from the resin injection hole to perform resin molding. For this reason, when resin molding is performed in a state in which the positions where the salient poles are allocated are varied, the motor rotation tends to become unstable, and in this case, there is a problem that vibration and noise are not caused by a large torque ripple.
In addition, since the resin is injected and filled in the space between the salient pole with the bobbin and the case or the pole tooth ring, a large amount of resin is required. There is a problem that the cost increases due to the price increase, and a large molding machine is required to take a large number of pieces, so that the production efficiency does not increase.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a uniform allocation position of split salient poles in a radial gap type DC brushless motor having a split salient pole structure. It is intended to stabilize and suppress the generation of torque ripple and reduce vibration and noise.
Another object of the present invention is to reduce the amount of resin used in the manufacturing process of a radial gap type DC brushless motor having a split type salient pole structure, thereby reducing the cost and improving the efficiency of assembly work.

In order to solve the above-described problem, the stepping motor of the present invention has a salient pole subassembly in which a plurality of divided salient poles are integrally fixed by a resin mold, whereby the salient poles have a split structure. Despite this, the allocation position of each salient pole is stabilized uniformly.
(Aspect of the Invention)
The following aspects of the present invention exemplify the configuration of the present invention, and will be described separately for easy understanding of various configurations of the present invention. Each item does not limit the technical scope of the present invention. Therefore, the technical aspects of the present invention also apply to those in which some of the constituent elements in each section are replaced, deleted, or other constituent elements are added while taking into account the best mode for carrying out the invention. It can be included in the range.

  (1) A radial gap type DC brushless motor including a stator having a bobbin wound with a coil mounted on each of a plurality of divided salient poles, wherein the plurality of salient poles are arranged radially. A radial gap type DC brushless motor in which a salient pole subassembly constructed integrally with resin is mounted inside a hollow cylindrical pole tooth ring made of a soft magnetic material (Claim 1).

In the radial gap type DC brushless motor described in this section, a plurality of salient poles are radially arranged and integrally formed of resin, and the salient pole subassembly has a plurality of salient poles divided. Nevertheless, by itself (independently), the allocation position of each salient pole is uniformly stabilized. The salient pole subassembly uses a mold to mold the salient poles by resin molding in a state where each salient pole is accurately positioned in the mold with reference to a predetermined inner diameter of the stator. It can be improved easily. As a result, it is possible to reduce vibration and noise by suppressing the occurrence of torque ripple in the DC brushless motor.
In addition, with the salient pole subassembly mounted inside the hollow cylindrical pole tooth ring made of soft magnetic material, the space between each salient pole and the pole tooth ring (between adjacent coils) Therefore, the amount of resin used in the DC brushless motor can be reduced. As a result, the weight and cost of the entire motor can be reduced.

(2) A radial gap type DC brushless motor in which a bearing housing of a bearing holding a bearing of a rotor shaft is integrally formed with the resin at one end in the axial direction of the salient pole subassembly.
In the radial gap type DC brushless motor described in this section, the bearing housing that holds the bearing of the rotor shaft is integrally formed of resin at one end in the axial direction of the salient pole subassembly, thereby reducing the number of parts. In addition, the accuracy of the coaxiality between the stator and the rotor can be improved.

(3) A radial gap type DC brushless motor in which a slit is formed on the rotor-facing surface of the salient pole, and the slit is filled with the resin.
In the radial gap type DC brushless motor described in this section, a slit is formed on the surface of the salient pole facing the rotor, and the resin is filled in the slit, thereby forming the molding portion by the salient pole subassembly resin. This is to strengthen the connection with the salient pole.

(4) A radial gap type DC brushless motor in which a plurality of axial slits extending in the axial direction are formed in the pole tooth ring, a protrusion is formed in the salient pole, and the protrusion is inserted into the axial slit. (Claim 4).
In the radial gap type DC brushless motor described in this section, a plurality of slits extending in the axial direction are formed in the pole tooth ring, a protrusion is formed in the salient pole, and the protrusion is inserted into the slit. The salient pole can be easily attached to the pole tooth ring.

(5) A radial gap type DC brushless motor in which the pole tooth ring is fitted inside a hollow cylindrical stator ring made of a soft magnetic material.
In the radial gap type DC brushless motor described in this section, the magnetic resistance of the magnetic path formed in the stator is reduced by fitting the pole tooth ring inside the hollow cylindrical stator ring made of a soft magnetic material. Is done.

(6) A manufacturing method of a radial gap type DC brushless motor including a stator configured by attaching a bobbin around which a coil is wound to each of a plurality of divided salient poles,
(A) punching out a soft magnetic plate into a substantially T-shape and stacking a plurality thereof, caulking the stacked soft magnetic plates to form the plurality of divided salient poles;
(B) A plurality of the salient poles are radially set at predetermined positions of the mold, and a resin is injected into the mold and resin molding is performed, thereby integrally molding the plurality of salient poles with the resin, And a step of forming a salient pole subassembly formed by a resin and forming a space extending in the axial direction in the center;
(C) attaching a bobbin around which a coil is wound to each salient pole of the salient pole subassembly; and
(D) attaching the salient pole subassembly equipped with the bobbin to the inside of a hollow cylindrical pole tooth ring made of a soft magnetic material;
(E) a step of fitting and attaching the pole tooth ring to the inner periphery of a hollow cylindrical stator ring made of a soft magnetic material;
(F) A method of manufacturing a radial gap type DC brushless motor, comprising: housing a rotor in an axially extending space formed in the center of the salient pole subassembly.

In the manufacturing method of the radial gap type DC brushless motor described in this section, a plurality of salient poles having a divided structure are radially set at predetermined positions of a mold, and a resin is injected into the mold. Accordingly, the position accuracy of the salient poles can be easily improved by integrally molding the plurality of salient poles with the resin. As a result, generation of torque ripple can be suppressed and vibration and noise can be reduced.
In addition, a bobbin around which a coil is wound is attached to each salient pole of the salient pole subassembly, and the salient pole subassembly is attached to the inside of a hollow cylindrical pole tooth ring made of a soft magnetic material. Since there is no need to fill the space between each salient pole and pole tooth ring, the amount of resin used can be reduced. As a result, the weight and cost of the entire motor can be reduced.
Furthermore, the magnetic resistance of the magnetic path formed in the stator is reduced by fitting and attaching the pole tooth ring to the inner periphery of a hollow cylindrical stator ring made of a soft magnetic material.
And the main structure part of a motor is completed by accommodating a rotor in the space extended in the axial direction formed in the center of a salient pole subassembly.

(7) In the step of forming the salient pole subassembly, a radial gap type DC brushless motor manufacturing method in which a bearing housing for holding a bearing of a rotor shaft is integrally formed at one axial end of the salient pole subassembly ( Claim 7).
The radial gap type DC brushless motor manufacturing method described in this section is a method in which a bearing housing of a bearing holding a rotor shaft bearing is integrally molded with resin at one end in the axial direction of the salient pole subassembly. The number of points can be reduced, and the accuracy of the coaxiality between the stator and the rotor can be improved.
(8) In the step of forming the plurality of salient poles, a radial gap type DC that fills the slit with the resin in the step of forming a slit on the rotor-facing surface of the salient pole and forming the salient pole subassembly. A method for manufacturing a brushless motor (Claim 8).
In the manufacturing method of the radial gap type DC brushless motor described in this section, a slit is formed on the surface of the salient pole facing the rotor, and a resin is filled in the slit, so that the resin molding location of the salient pole subassembly and the salient pole It makes the bond stronger.

(9) In the step of forming the plurality of salient poles, projections are formed on the salient poles, and salient pole subassemblies equipped with the bobbins are arranged inside the hollow cylindrical pole tooth ring made of a soft magnetic material. Prior to the step of attaching to the pole tooth ring, a plurality of axial slits extending in the axial direction are formed in the pole tooth ring, and the salient pole subassembly to which the bobbin is attached is a hollow cylindrical pole tooth ring made of a soft magnetic material. A method of manufacturing a radial gap type DC brushless motor in which the protrusions of the salient poles are inserted into the axial slits of the pole tooth ring in the step of mounting on the inside of the pole teeth.
In the manufacturing method of the radial gap type DC brushless motor described in this section, a plurality of axial slits extending in the axial direction are formed in the pole tooth ring, protrusions are formed on the salient poles, and the protrusions are axial slits. By inserting, salient poles can be easily mounted.

Since the present invention is configured as described above, in the radial gap type DC brushless motor having the split type salient pole structure, the allocation position of the split type salient pole is uniformly stabilized to suppress the generation of torque ripple, and the vibration It becomes possible to reduce noise.
Further, in the manufacturing process of the radial gap type DC brushless motor having a split type salient pole structure, it is possible to reduce the amount of resin to be used, thereby reducing the cost and improving the efficiency of the assembly work.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Here, parts that are the same as or correspond to those in the prior art are denoted by the same reference numerals, and detailed description thereof is omitted.
FIGS. 1 to 6 show a radial gap type DC brushless motor 1 having an inner rotor type split salient pole structure according to an embodiment of the present invention and its components. The basic structure of the DC brushless motor 1 according to the embodiment of the present invention is the same as that of the conventional motor structure 200 shown in FIGS. 10 to 12, but the structure of the stator assembly 17 will be described below. And its manufacturing process is significantly different.

  The stator assembly 17 shown in an exploded perspective view in FIG. 6 has a plurality of salient poles 4 (FIGS. 2 to 5) arranged radially and integrally formed with a resin 5 (FIG. 2). The pole subassembly 3 (FIG. 2) is mounted inside a hollow cylindrical pole tooth ring 15 made of a soft magnetic material, and the pole tooth ring 15 is fitted inside a hollow cylindrical stator ring 16 made of a soft magnetic material. It has a combined structure.

Here, the assembly procedure of the stator assembly 17 will be described.
First, the salient pole 4 of the DC brushless motor 1 has a predetermined number of soft magnetic plates (for example, galvanized steel plate, electromagnetic steel plate, silicon steel plate, etc.) punched into a substantially T shape by a press as in the prior art (this embodiment). In this case, four sheets are stacked and then fixed by crimping (see FIG. 5).

  Subsequently, a plurality of (six in this embodiment) salient poles 4 are set at predetermined positions of a mold (not shown). At this time, the soft magnetic plates constituting the salient poles 4 are set in the mold so as to be laminated in the circumferential direction. Then, a synthetic resin (for example, PBT (polybutylene terephthalate), liquid crystal polymer, etc.) is injected into the mold, and the salient pole 4 is resin-molded. At this time, the salient poles 4 are combined with the resin 5 and at the same time, the bearing housing 6 and the boss 7 are integrally formed with the resin 5 and the space extends in the axial direction at the center (center hole 9: FIG. 4). ) Is formed of the resin 5. By taking out the integrally molded product from the mold, as shown in FIGS. 2 and 3, it is possible to obtain the salient pole subassembly 3 in which the salient poles 4 are radially arranged with a resin mold.

  The central hole 9 of the salient pole subassembly 3 is a space for accommodating the rotor 18, and the diameter of the central hole 9 is the outer diameter of the rotor magnet 21 (FIG. 1) and the rotor magnet 21 and the salient pole 4. The dimension is set in consideration of the gap (gap) provided therebetween. The bearing housing 6 that holds the sleeve bearing 23 (FIG. 1) of the rotor shaft 19 (FIG. 1) is molded at one end of the salient pole subassembly 3 so as to close one end of the central hole 9. Yes. Further, a plurality of holes 8 (FIGS. 3 and 4) are formed simultaneously with the bearing housing 6, and this hole 8 becomes a space for accommodating the Hall element 11 (FIG. 1) for detecting the position of the rotor 18.

Further, as shown in FIGS. 1 and 4, in the embodiment of the present invention, a circumferential slit 10 is formed at the center of the salient pole 4, and each salient pole 4 faces the outer circumferential surface of the rotor 18. The surface is partially cut in the axial direction by the slit 10 and the resin 5 is filled into the slit 10 during resin molding.
Although the slit 10 is not an essential component, the resin 5 is filled in the slit 10 to further strengthen the connection between the salient pole subassembly 3 and the salient pole 4 in the salient pole subassembly 3. Is possible.

  Next, the projections 4a of the salient poles 4 of the salient pole subassembly 3 are inserted into the holes 12a of the bobbin 12 formed of synthetic resin, and the salient poles 4 are positioned in the slits 12b of the bobbin 12, so that the bobbin 12 To obtain the salient pole assembly 2. The coil 13 is wound around the bobbin 12 in advance with a predetermined number of turns, and the lead portion of the coil 13 is entangled with the terminal 14 planted on the flange 12c of the bobbin 12 and soldered.

  Then, the protrusion 4a of the salient pole 4 projecting from the flange 12d of the bobbin 12 is inserted into an axial slit 15a formed in a pole tooth ring 15 made of a hollow cylindrical and soft magnetic metal material. As shown in FIG. 6, the axial slits 15 a extend in the axial direction from one end of the pole tooth ring 15 to a substantially central portion, and the same number as the salient poles 4 is formed. Then, the salient pole assembly 2 can be accurately positioned and attached to the inside of the pole tooth ring 15 by inserting the projection 4a of each salient pole 4 with the opening at one end of the slit 15a as a guide.

Next, the pole tooth ring 15 having the salient pole assembly 2 attached to the inside thereof is fitted into and attached to the inside of the stator ring 16 made of a hollow cylindrical and soft magnetic metal material to obtain the stator assembly 17. The pole tooth ring 15 and the stator ring 16 function as a yoke in the stator of the DC brushless motor 1. By fitting the pole tooth ring 15 having the salient pole assembly 2 attached inside the stator ring 16, The magnetic resistance of the magnetic path in the stator can be reduced.
The pole tooth ring 15 and the stator ring 16 are both easily and inexpensively manufactured into a predetermined cylindrical shape by forming a soft magnetic metal plate in a cylindrical shape and welding the joining portion (joining portion). be able to.

Next, an assembly procedure of the DC brushless motor 1 according to the embodiment of the present invention will be described.
First, the sleeve bearing 23 is press-fitted and attached to the bearing housing 6 of the salient pole subassembly 3, and the rotor 18 is inserted into the inner periphery of the stator assembly 17 through the opening on the other side of the salient pole assembly 2.
The rotor 18 includes a rotor shaft 19, a sleeve 20 made of a nonmagnetic material attached to the outer periphery of the rotor shaft 19, and a hollow cylindrical rotor magnet 21 fixed to the outer periphery of the sleeve 20. Are multipolarly magnetized in the circumferential direction. A resin spacer 22 is attached to one end of the rotor magnet 21. Since the resin spacer 22 is in contact with an inner ring of a ball bearing 30 to be described later, the resin spacer 22 is formed of a resin having good slidability. Although the illustrated rotor magnet 21 is a plastic magnet, it is not limited to this, and a rare earth bonded magnet or a sintered magnet may of course be used.

Further, when one side of the rotor shaft 19 is inserted into the sleeve bearing 23 and the rotor 18 is accommodated in the inner periphery of the stator assembly 17, a preload composed of resin preload holders 25 and 26 and a coil spring 27 is formed. The device 24 is accommodated in the other end of the rotor magnet 21 and interposed between the sleeve 20 and the sleeve bearing 23.
Then, a cover member 28 made of resin (for example, PBT resin) is fitted on the inner periphery of the pole tooth ring 15 and placed on the salient pole assembly 2. The resin cover member 28 is for preventing dust and dirt from entering the motor.

Next, in a state where the ball bearing 30 is mounted on the inside of a bearing holder 29 made of resin (for example, PBT resin), the other side of the rotor shaft 19 is inserted into the ball bearing 30, and the bearing holder 29 is attached to the cover member 28. Place on top. At this time, a claw portion (not shown) formed on the outer periphery of the bearing holder 29 is positioned in a concave portion (not shown) formed in the central portion of the cover member 28, whereby the mounting means and the bearing holder 29 are rotated. Acts as a stop.
Then, the bearing holder 29 is inserted through a central hole 31a formed in the upper plate 31, the upper plate 31 is inserted into the other end of the stator ring 16, and the upper plate 31 and the stator ring 16 are fixed by welding. . At this time, the concave portion (not shown) formed on the outer periphery of the upper plate 31 and the claw portion (not shown) formed on the end surface of the stator ring 16 are engaged, whereby the upper plate 31 rotates with respect to the stator ring 16. Acts as a stop.

Finally, the boss portion 7 formed integrally with the salient pole subassembly 3 is inserted into a hole 33a formed in the printed wiring board 33 on which components such as the Hall element 11 and the connector 32 are mounted. The terminal 14 of the bobbin 12 is inserted into a through hole 33b formed in the printed wiring board 33 and soldered for connection.
At this time, the Hall element 11 is accommodated in the hole 8 formed when the salient pole subassembly 3 is formed, so that the Hall element 11 is arranged to face the end face of the rotor magnet 21, and the position of the rotor 18 is changed. It becomes possible to detect. Then, the lower plate 34 is attached to one end of the stator ring 16 with the lower plate 34 inserted through the boss portion 7. At this time, like the upper plate 31, a recess (not shown) formed on the outer peripheral surface engages with a claw portion (not shown) formed on the end surface of the stator ring 16, so that the lower plate with respect to the stator ring 16 is engaged. 34 functions as a rotation stopper.

The rotation stopping mechanism for the upper plate 31 and the lower plate 34 is not limited to this. For example, a claw portion is formed on the outer periphery of the upper plate 31 and the lower plate 34, and an opening formed in the stator ring 16. Needless to say, the claw portion may be engaged with the rotation stop and mounting means.
By such a procedure, the DC brushless motor 1 having a split salient pole structure according to the embodiment of the present invention is completed.

According to the embodiment of the present invention configured as described above, the following operational effects can be obtained.
First, the salient pole subassembly 3 constituted by a plurality of salient poles 4 being radially arranged and integrally molded with a resin 5 has a plurality of salient poles 4 in a divided structure. (Independently) The allocation position of each salient pole 4 is stabilized uniformly. Then, the salient pole subassembly 3 is resin-molded in a state where each salient pole 4 is accurately positioned in the mold with reference to a predetermined inner diameter of the stator by using a mold. The accuracy can be easily improved. As a result, generation of torque ripple of the DC brushless motor 1 can be suppressed and vibration and noise can be reduced.
Further, in a state where the salient pole subassembly 3 is mounted inside the hollow cylindrical pole tooth ring 15 made of a soft magnetic material, a space (adjacent to each other) between each salient pole 4 and the pole tooth ring 15 is also provided. Since it is not necessary to fill the resin 5 between the coils), the amount of resin used in the DC brushless motor 1 can be reduced. As a result, the entire DC brushless motor 1 can be reduced in weight and cost.

In addition, the bearing housing 6 that holds the bearing 23 of the rotor shaft 19 is integrally formed with the resin 5 at one end in the axial direction of the salient pole subassembly 3, thereby reducing the number of parts and the stator (stator assembly). 17) and the accuracy of the coaxiality of the rotor 18 can be improved.
Further, a slit 10 (FIG. 4) is formed on the surface of the salient pole 4 facing the rotor 18, and the slit 5 is filled with the resin 5, so that the molding location and salient pole by the resin 5 of the salient pole subassembly 3. 4 can be further strengthened.
Further, a plurality of axial slits 15a extending in the axial direction are formed in the pole tooth ring 15, a protrusion 4a (FIG. 5) is formed in the salient pole 4, and the protrusion 4a is inserted into the axial slit 15a. The salient pole 4 can be easily attached to the pole tooth ring 15.
Further, the pole tooth ring 15 is fitted inside the hollow cylindrical stator ring 16 made of a soft magnetic material, so that the magnetic resistance of the magnetic path formed in the stator (stator assembly 17) is reduced.

In addition, as a method of manufacturing the DC brushless motor 1 according to the embodiment of the present invention,
(A) punching out a soft magnetic plate into a substantially T-shape and laminating a plurality thereof, caulking the laminated soft magnetic plates to form a plurality of divided salient poles 4;
(B) A plurality of salient poles 4 are radially set at predetermined positions on a mold, and a resin 5 is injected into the mold and molded by resin molding. And forming the salient pole subassembly 3 formed by forming a space (center hole 9) extending in the axial direction in the center by the resin 5,
(C) attaching a bobbin 12 around which a coil 13 is wound to each salient pole 4 of the salient pole subassembly 3;
(D) mounting the salient pole subassembly 3 with the bobbin 12 mounted inside a hollow cylindrical pole tooth ring 15 made of a soft magnetic material;
(E) a step of fitting and attaching the pole tooth ring 15 to the inner periphery 16 of a hollow cylindrical stator ring made of a soft magnetic material;
(F) The step of accommodating the rotor 18 in the axially extending space (center hole 9) formed in the center of the salient pole subassembly 3 is included.

According to such a manufacturing method, a plurality of salient poles 4 having a divided structure are radially set at predetermined positions of a mold, and a resin 5 is injected into the mold to be resin-molded. By integrally molding 4 with the resin 5, the positional accuracy of the salient pole 4 can be easily improved. As a result, generation of torque ripple in the DC brushless motor 1 can be suppressed, and vibration and noise can be reduced.
A bobbin 12 around which a coil 13 is wound is attached to each salient pole 4 of the salient pole subassembly 3, and the salient pole subassembly 3 is placed inside a hollow cylindrical pole tooth ring 15 made of a soft magnetic material. Since it is not necessary to fill the space between each salient pole 4 and pole tooth ring 15 with resin 5 after mounting, the amount of resin to be used can be reduced. As a result, the weight and cost of the entire motor can be reduced.

Further, the pole teeth ring 15 is fitted and attached to the inner periphery of a hollow cylindrical stator ring 16 made of a soft magnetic material, thereby reducing the magnetic resistance of the magnetic path formed in the stator (stator assembly 17). Is done.
The main structure portion of the DC brushless motor 1 is completed by housing the rotor in an axially extending space (center hole 9) formed in the center of the salient pole subassembly 3.

  As described above, the DC brushless motor 1 having the divided salient pole structure according to the embodiment of the present invention has been described. However, the present invention is not limited to the above embodiment, and can be changed within the scope of the present invention. Needless to say.

1 is an axial sectional view of a radial gap type DC brushless motor having an inner rotor type split salient pole structure according to an embodiment of the present invention. FIG. 2 is a perspective view of a salient pole subassembly of the DC brushless motor shown in FIG. 1. FIG. 3 is a plan view of the salient pole subassembly shown in FIG. 2. It is sectional drawing in the AA of FIG. FIG. 3 is a schematic diagram illustrating a manufacturing process of the salient pole subassembly of FIG. 2 and a process of attaching a bobbin to the salient pole. FIG. 2 is an exploded perspective view of a stator assembly of the DC brushless motor shown in FIG. 1. It is an axial sectional view of a conventional radial gap type DC brushless motor. FIG. 8 is an exploded perspective view of a main part of the DC brushless motor shown in FIG. 7. It is a bobbin single figure of the DC brushless motor shown in FIG. It is an axial sectional view showing another example of a conventional radial gap type DC brushless motor. It is a bobbin single figure of the DC brushless motor shown in FIG. FIG. 11 is an exploded perspective view of a stator assembly of the DC brushless motor shown in FIG. 10.

Explanation of symbols

  1: DC brushless motor, 3: salient pole subassembly, 4: salient pole, 4a: protrusion, 5: resin, 6: bearing housing, 10: slit, 12: bobbin, 13: coil, 15: pole tooth ring, 15a : Axial slit, 16: Stator ring, 18: Rotor, 19: Rotor shaft, 21: Rotor magnet, 23: Sleeve bearing, 29: Bearing holder

Claims (9)

Each of the plurality of divided salient poles is a radial gap type DC brushless motor including a stator configured by mounting a bobbin around which a coil is wound. The plurality of salient poles are arranged radially and are made of resin. A radial gap type DC brushless motor characterized in that a salient pole subassembly formed by integral molding is mounted inside a hollow cylindrical pole tooth ring made of a soft magnetic material. 2. The radial gap type DC brushless motor according to claim 1, wherein a bearing housing of a bearing holding a bearing of a rotor shaft is integrally formed with the resin at one end of the salient pole subassembly in the axial direction. . The radial gap type DC brushless motor according to claim 1, wherein a slit is formed on a surface of the salient pole facing the rotor, and the slit is filled with the resin. A plurality of axial slits extending in the axial direction are formed in the pole tooth ring, a protrusion is formed in the salient pole, and the protrusion is inserted into the axial slit. 4. A radial gap type DC brushless motor according to any one of items 3 to 4. The radial gap type DC brushless motor according to any one of claims 1 to 4, wherein the pole tooth ring is fitted inside a hollow cylindrical stator ring made of a soft magnetic material. A method of manufacturing a radial gap type DC brushless motor including a stator configured by attaching a bobbin around which a coil is wound to each of a plurality of divided salient poles,
(A) punching out a soft magnetic plate into a substantially T-shape and stacking a plurality thereof, caulking the stacked soft magnetic plates to form the plurality of divided salient poles;
(B) A plurality of the salient poles are radially set at predetermined positions of the mold, and a resin is injected into the mold and resin molding is performed, thereby integrally molding the plurality of salient poles with the resin, And a step of forming a salient pole subassembly formed by a resin and forming a space extending in the axial direction in the center;
(C) attaching a bobbin around which a coil is wound to each salient pole of the salient pole subassembly; and
(D) attaching the salient pole subassembly equipped with the bobbin to the inside of a hollow cylindrical pole tooth ring made of a soft magnetic material;
(E) a step of fitting and attaching the pole tooth ring to the inner periphery of a hollow cylindrical stator ring made of a soft magnetic material;
(F) including a step of housing the rotor in a space extending in the axial direction formed in the center of the salient pole subassembly, and a method of manufacturing a radial gap type DC brushless motor. The radial gap according to claim 6, wherein in the step of forming the salient pole subassembly, a bearing housing that holds a bearing of the rotor shaft is integrally formed at one axial end of the salient pole subassembly. Of manufacturing a brushless DC brushless motor. The step of forming the plurality of salient poles includes forming a slit on a rotor-facing surface of the salient pole, and filling the slit with the resin in the step of forming the salient pole subassembly. A manufacturing method of a radial gap type DC brushless motor according to 6 or 7. In the step of forming the plurality of salient poles, projections are formed on the salient poles, and salient pole subassemblies with the bobbins are fitted inside a hollow cylindrical pole tooth ring made of a soft magnetic material. Prior to the process, a plurality of axial slits extending in the axial direction are formed in the pole tooth ring,
In the step of mounting the salient pole subassembly equipped with the bobbin inside the hollow cylindrical pole tooth ring made of soft magnetic material, inserting the salient pole protrusion into the axial slit of the pole tooth ring. The manufacturing method of the radial gap type DC brushless motor of any one of Claim 6 to 8 characterized by the above-mentioned.

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