JP2009142087A - Electric motor and electric-motor manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small and thin electric motor while achieving high efficiency and improvement in productivity. <P>SOLUTION: An electric motor is configured as follows: a compact is formed by compressing magnetic powder. The compact has an annular base part 2' and a plurality of claw magnetic poles 2a circumferentially formed while protruding from the base part 2'. The electric motor is provided with a stator core in which the compacts are arranged oppositely to each other. Each claw magnetic pole of the other compact is located between the claw magnetic poles of one compact. The compact has a plurality of recessed parts 2b on the inner peripheral side of the base part 2' and between the claw magnetic poles 2a so as to allow positioning protrusions 5a to be inserted therein. Accordingly, when executing resin-molding in a die 5, it is possible to execute positioning by the protrusions 5a. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electric motor and a method for manufacturing the electric motor.

  An electric motor is used as a drive source in various applications, and is often used by being incorporated in various products. For example, it is also used for blowers, compressors for refrigeration and air conditioning, and so-called auxiliary machines such as automobile power windows and wipers. As described above, regarding an electric motor incorporated in a product, not only high efficiency but also miniaturization (thinning) or improvement in assemblability is required. And the shape of the rotor or stator for improving efficiency, downsizing, and improving assemblability has been studied.

  Patent Document 1 discloses a configuration of a stepping motor for reducing the size and improving the productivity, and Patent Document 2 discloses positioning for the outer periphery of the core flat portion in order to position the core in the rotational direction. A configuration having a V-shaped groove is disclosed. Further, Patent Document 3 discloses a multiphase claw pole type motor, and it is possible to obtain a claw type magnetic pole having a complicated shape while facilitating manufacture by compressing magnetic powder, thereby achieving high efficiency of the motor. Is going on.

  Patent Documents 4 to 6 disclose a configuration using a bobbin with respect to positioning of the core.

JP 2005-287288 A Japanese Patent Laid-Open No. 4-17538 JP 2006-296188 JP JP-A-8-116659 JP 2005-304164 A JP-A-10-295070

  In order to reduce the size and increase the efficiency of the motor while improving the manufacturability, the positioning of the core is important. In particular, in a configuration in which cores having magnetic poles are arranged to face each other, positional deviation between both cores affects magnetic field formation, so that it is necessary to facilitate positioning.

  In Patent Document 1, a metal plate formed in the same shape is used as a pair of stators, and positioning is performed by forming positioning holes and through holes in the stators. Moreover, in patent document 2, it has a V-shaped groove | channel on the outer periphery of a core flat part, and the positioning of the rotation direction of a core is performed using the slider for positioning. Furthermore, in patent document 3, a convex part and a ditch | groove are provided in a core, or a fitting protrusion and a fitting hole are provided (refer FIGS. 15-18), and positioning is aimed at by this.

  As shown in these patent documents 1 to 3, when a positioning structure is provided on the core, sufficient core strength is required. In Patent Document 1, it is considered that a positioning hole can be easily formed because a core obtained by molding a metal plate with a mold is used. However, when the core strength is low, the strength is further reduced by providing a through hole. As a result, the handling and reliability in the subsequent manufacturing process are reduced.

  In particular, Patent Document 3 uses a core formed by compression molding of magnetic powder to facilitate the formation of magnetic poles, but the core itself is only a compression of magnetic powder and it is easy to ensure sufficient strength. is not. Therefore, although positioning by a concavo-convex shape is employed without providing a through hole, the shape becomes complicated. One of the merits of compression molding is that a claw-shaped magnetic pole with a complicated shape is obtained, but unlike the claw-shaped magnetic pole, the positioning structure does not contribute to high efficiency as an electric motor after positioning is performed. A simple shape is desirable in terms of strength.

  In Patent Documents 4 to 6, positioning is performed using a bobbin. However, in Patent Document 4, a fitting between a bobbin positioning projection and a notch provided in the outer periphery of the core is used (paragraph 0037 and the like). Reference) and the same problem as in Patent Documents 1 to 3 may occur in that the core has a positioning structure.

  Patent Documents 5 to 6 disclose examples in which a positioning portion that protrudes toward the inner peripheral side of the bobbin is disclosed, and thereby the core is positioned, but these all protrude toward the inner peripheral side where the rotor is disposed. Therefore, the presence of the positioning portion has an influence on the shape of the magnetic pole and the distance between the magnetic poles, and the efficiency is restricted.

  As described above, when using a core formed by compression molding of magnetic powder, it is necessary to simplify the core shape in terms of strength. An example of a method that enables positioning in a simple core shape and the problems that may occur at the time of positioning two opposing cores that form one phase (hereinafter referred to as “upper and lower cores” referring to both cores) It demonstrates, showing.

  FIG. 8 shows an example in which irregularities are provided on the joint surface on the outer periphery of the core for positioning the core, and by combining them, the distance between the claw-shaped magnetic poles becomes equal. In this example, when magnetic powder is compression molded to obtain a powder magnetic core, damage due to stress concentration of the mold is prevented, and when the molded body is removed from the mold, the molded body is fixed to the mold by the spring back, and the molded body In order to prevent the device itself from being damaged, the case where the side surface of the uneven shape is inclined is shown.

  Since this dust core is made by pressing and compacting iron powder, it is difficult to obtain dimensional accuracy in the pressing direction during molding in addition to strength. Therefore, unevenness in the height direction may occur.

  At this time, when the convex part becomes higher than the concave part among the concaves and convexes engaged with each other, a gap is formed on the upper and lower core joint surfaces (see FIG. 8B). On the other hand, when the convex portion is lower than the concave portion depth, a gap is formed on the side surface between the concave and convex portions (see FIG. 8C), so that the positional accuracy of the upper and lower cores, particularly the accuracy in the rotation direction is deteriorated. Misalignment occurs.

  These states shown in FIGS. 8B and 8C cause the deterioration of the characteristics of the motor, and not only cause a decrease in the performance of the motor, but also a variation in the performance of the motor, that is, individual motors to be mass-produced. It was easy to make a difference.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a small and thin electric motor while improving productivity and increasing efficiency.

  In order to achieve the above object, a molded body having an annular base and a plurality of claw-shaped magnetic poles protruding from the base and formed in the circumferential direction is molded by compressing magnetic powder, and the molded body is opposed to the molded body. In the electric motor having a stator core disposed in a manner such that the claw-shaped magnetic pole of another molded body is positioned between the claw-shaped magnetic poles of one molded body, The body is characterized in that it has a plurality of concave shapes into which positioning projections are inserted between the claw-shaped magnetic poles on the inner peripheral side of the base portion.

  This first invention is further characterized in that a protrusion provided on the mold is inserted into the concave shape.

  Further, the invention in the method of manufacturing an electric motor relates to a protrusion provided on the upper and lower molds and an engagement portion provided on the molded body in the step of resin molding by holding the molded body with the upper and lower molds. In addition, it is characterized in that positioning in the circumferential direction of the molded body that is arranged to face is performed.

  Further, in the step of holding the molded body with the upper and lower molds and resin molding, a concave shape provided between the protrusion provided on the upper and lower molds and the claw mold magnetic pole on the inner peripheral side of the base portion And is engaged.

  According to the present invention, it is possible to provide a small and thin electric motor while improving productivity and increasing efficiency.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In this section, a configuration will be described in which a molded body formed by compressing magnetic powder is disposed opposite to a stator core, and the molded body formed of the powder magnetic core is positioned without any special unevenness. First, the structure of the electric motor of this embodiment is demonstrated using FIG.1 and FIG.2.

  FIG. 1 is an exploded perspective view of one phase (reference numeral 3) of a stator used in the electric motor of the present embodiment. As shown in FIG. 1, the upper and lower cores are opposed to a dust core 2 formed by compressing magnetic powder, thereby constituting a stator core. That is, in this embodiment, the upper and lower cores for one phase are constituted by opposingly arranging the dust cores 2 having the same shape.

  A plurality of claw-type magnetic poles 2a are formed on the dust core 2, and the claw-type magnetic poles 2a of one dust core 2 and the claw-type magnetic poles 2a of the other dust core 2 do not interfere with each other. Are combined. Therefore, in the example shown in the present embodiment, 24 claw-type magnetic poles including the upper and lower cores are arranged adjacent to the inner peripheral surface of the stator.

  The bobbin 1 is sandwiched between the powder cores 2 arranged to face each other. A coil is wound around the bobbin 1, and the electric motor is rotated by passing a current through the coil. The bobbin 1 is provided with a core positioning protrusion 1a. The effect of the protrusion 1a will be described later.

  FIG. 2 is an exploded view of the three-phase crotice motor. The stator 10 is obtained by laminating the upper and lower cores 2, the bobbin 1 and the coil shown in FIG. 1 in three phases, and a rotor 11 configured by combining a shaft, a rotor core, and a magnet is inserted into the center of the stator 10. Brackets are arranged on both sides of the stator 10, and in FIG. 2, both end surfaces of the stator 10 are sandwiched between the load side bracket 12a and the anti-load side bracket 12b. The rotor 11 is supported by a bearing 13, and each component is fixed by a through screw 14 in order to form a laminated structure thereof.

  3 is a view showing a cross section of the stator 10 shown in FIG. 2, and FIG. 4 is an external perspective view showing a stator shape for three phases inside the stator 10. As shown in FIG. FIG. 5 is an exploded view of one phase 3 of the three-phase stator 10 of FIG. 4, and a copper wire is placed on the insulating bobbin 1 between two opposing dust cores 2. It shows that the coil 4 produced by winding is sandwiched.

  Moreover, the recessed part is provided in the outer peripheral side surface of the powder core 2. As shown in FIG. By combining the upper and lower cores, this recess becomes an opening, from which the winding is drawn. In the case of three-phase lamination, there are also three winding lead portions, but by arranging them close to each other, an electric motor can be configured with a simple configuration.

  As shown in FIGS. 1 to 5, the claw-shaped magnetic pole 2 a provided on the dust core 2 is arranged adjacent to the inner peripheral surface of the stator 10, that is, the portion facing the rotor 11, Flows, a magnetic flux is generated between the magnetic poles adjacent to each other. As a result, a rotational force is generated in the rotor 11 to function as an electric motor.

  Next, the positioning of the upper and lower cores in this embodiment will be described while showing a more specific configuration.

  As shown in FIG. 1, the upper and lower cores are opposed to a dust core 2 made of a magnetic powder compact, and claw-shaped magnetic poles 2a provided on the dust core 2 are arranged adjacent to each other. The bobbin 1 includes a plurality of core positioning protrusions 1a. The protrusion 1a protrudes on both the upper and lower sides toward the dust core 2 that sandwiches the bobbin 1, and the protrusion 1a is inserted between the claw-type magnetic poles 2a of the dust core 2. In addition, as shown in FIG. 1, the protrusions 1a protruding on both the upper and lower sides protrude alternately in the upper and lower directions, and can be easily inserted into a concave shape 2b described later.

  The dust core 2 and the bobbin 1 are of an annular shape, and the claw-shaped magnetic pole 2a of one dust core 2 and the claw-shaped magnetic pole 2a of the other dust core 2 are alternately arranged as shown in FIG. Both cores are combined so that they line up. At this time, the distance between the claw-shaped magnetic poles 2a adjacent to each other in a state where the upper and lower cores are combined is defined as L4.

  Since the upper and lower cores are combined in this way, the claw-type magnetic pole 2a constituting the inner peripheral surface of the stator 10 has a circumferential width L2 smaller than the distance L1 between the claw-type magnetic poles 2a.

  Further, the annular dust core 2 is provided with a recess 2b between the claw-shaped magnetic poles 2a in the planar base 2 '. As shown in the figure, the concave shape 2b has a concave shape in the annular surface of the base portion 2 ′ between the claw-shaped magnetic poles 2a, and is notched in the annular surface of the base portion 2 ′. It is formed without providing a special uneven shape.

  In the state where the upper and lower cores are combined, the tip of the claw-shaped magnetic pole 2a of the other dust core 2 is located in the recess 2b, so the width of the recess 2b in the inner peripheral portion of the dust core 2 is larger than L2. It has become big. Further, the protrusion 1a of the bobbin 1 is inserted into the root portion of the concave shape 2b. Therefore, the circumferential width L3 of the concave shape 2b is the same as the width L3 of the protrusion 1a provided on the bobbin 1 in a state where the dust core 2 and the bobbin 1 are combined.

  By providing the above configuration, the protrusion 1a of the bobbin 1 is inserted into the concave shape 2b of the dust core 2 so that the upper and lower cores are positioned, and the dust core 2 is not displaced in the rotational direction. Moreover, since the protrusion 1a protrudes not on the inner peripheral side but on each dust core 2 side, it does not affect the arrangement of the adjacent claw-type magnetic poles 2a on the rotor 11 side, and between adjacent claw-type magnetic poles 2a. The distance L4 can be set to a desired value.

  Further, by placing the tip of the claw-shaped magnetic pole 2a in the concave shape 2b, the claw-shaped magnetic pole 2a can be arranged on the inner peripheral portion facing the rotor 11 without interfering with the base 2 ′ of the opposing dust core. it can. That is, it becomes a structure which can extend | stretch the front-end | tip part of the nail | claw-shaped magnetic pole 2a to the annular | circular surface of the base 2 'of the dust core 2 which opposes, and an effective magnetic path formation is attained.

  Further, in the upper and lower cores facing each other, a magnetic path is formed between the adjacent claw-shaped magnetic poles 2a, but the distance L5 between the tip portion of the claw-shaped magnetic pole 2a and the base 2 'is set to the adjacent claw-shaped magnetic pole 2a. Since the protrusion 1a of the bobbin 1 made of an insulating material is positioned between the distal end portion of the claw-type magnetic pole 2a and the base portion 2 ', the magnetic flux leakage is suppressed and the configuration is highly efficient. It can be. That is, since the distance L4 between the claw-type magnetic poles adjacent to each other is smaller than the distance L5 between the tip portion of the claw-type magnetic pole 2a and the bottom portion (base portion 2 ′) of the concave shape 2b, the influence on the magnetic flux formed during energization is affected. Can be reduced. In addition, since the radial width L6 of the protrusion 1a is substantially the same as L5, it contributes to magnetic flux leakage reduction.

  As described above, when a bobbin is used, the bobbin 1 is provided with protrusions 1a to be fitted with the core 2 on both sides, and the bobbin 1 and the core 2 are combined to combine the cores 2 to form a stator core. In doing so, they can be positioned at the required angle. Further, the leakage of magnetic flux can be suppressed from the positional relationship of the concave shape 2b, the protrusion 1a, and the claw-shaped magnetic pole 2a, and high efficiency can be achieved.

  FIG. 6 is a diagram illustrating an example of positioning the upper and lower cores different from the first embodiment. As described above, the dust core 2 of the present embodiment is made of a molded body obtained by compressing magnetic powder, and this point is the same as in Example 2. In the following, since the configuration is the same as that of the first embodiment except for the configuration specifically shown, the detailed description is omitted.

  The feature of the second embodiment is that a mold is used for positioning the upper and lower cores. Specifically, it is as follows. In the present embodiment, the core 2 is used in which the molded body obtained by compressing the magnetic powder is opposed to the core. The powder core 2 is used after being molded with a resin. When the molded body is molded, a mold is used to hold the molded body.

  FIG. 6 is a diagram illustrating an example of a mold used in the second embodiment. The mold 5 includes a molded body holding portion, and a molded body molded in the holding portion is installed. In the present embodiment, since the stator core is configured by arranging the dust cores 2 so as to face each other, the upper die and the lower die are also used as a set. In the following description, FIG. 6 shows a lower mold. That is, the left figure of FIG. 6 is a top view of the lower mold, and the right figure is a sectional view of the center line.

  When such a mold is used, when the powder core 2 is placed oppositely and molded with resin, if the upper and lower molds are positioned in the circumferential direction, the upper and lower cores after molding are positioned. It can be fixed. Therefore, the circumferential positioning of the dust core 2 can be performed without using a bobbin.

  As shown in FIG. 6, the mold 5 of this embodiment has holding parts for the molded bodies in the upper and lower mold dies, and the claw-shaped magnetic poles 2a or the recessed parts 2b of the dust core 2 are precisely placed in the holding parts. The projection 5a to be engaged is provided. By engaging the protrusion 5 a with an engaging portion provided on the dust core 2, the dust core 2 is positioned on the mold 5 while being restricted from moving in the circumferential direction. On the other hand, the dust core disposed opposite to the dust core 2 is similarly positioned by an upper mold (not shown).

  Therefore, a stator core can be obtained in a positioned state by combining upper and lower molds and performing molding resin molding while maintaining this state. Therefore, the claw-shaped magnetic poles 2a can be arranged at an equal pitch. In addition, the handleability of the stator 3 can be improved in the subsequent manufacturing process.

  FIG. 7 is a diagram showing an example using the electric motor shown in the first and second embodiments. In this example, an FFU is shown. A fan 21 is attached to a rotating shaft of the electric motor 20 and is housed in a housing 22 together with a filter 23 to constitute a fan filter unit (FFU). The housing 22 has an opening on the upper side, and air is taken in from the opening as the fan 21 rotates. That is, air is sucked from the upper part in the drawing by the rotation of the fan 21 and passes through the filter 23 attached below the fan 21.

  Therefore, when passing through the filter 23, the air is filtered and discharged to the downstream side (lower part in the figure) of the filter 23 as clean air. During operation of the FFU, it is possible to keep supplying clean air in the clean room by continuously supplying air from which dust or the like has been removed.

  Since the FFU of this embodiment is attached to the ceiling of a clean room, there is a strong demand for thinning. Since the filter 23, the electric motor 20, and the fan 21 are attached to the housing 22, the FFU can be reduced in thickness as the FFU by reducing the size of the electric motor 20.

The disassembled perspective view of 1 phase (code | symbol 3) of a stator. The exploded view of a three-phase Crotice motor. The figure which shows the cross section of a stator. The external appearance perspective view which shows the stator shape for three phases inside a stator. The figure which decomposed | disassembled and showed one phase part among the stators which consist of three phases. The figure which shows the other example which positions the up-and-down core. The figure which shows the structure of FFU of this embodiment. The figure which shows the example of positioning of a core, and a subject.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Bobbin, 1a ... Protrusion, 2 ... Powder core, 2 '... Base, 2a ... Claw-shaped magnetic pole, 2b ... Concave shape, 3 ... One phase, 4 ... Coil, 5 ... Mold, 5a ... Protrusion, 10 ... Stator, 11 ... rotor, 12 ... bracket, 13 ... bearing, 14 ... through screw, 20 ... electric motor, 21 ... fan, 22 ... FFU housing, 23 ... filter.

Claims (4)

A stator core having an annular base and a plurality of claw-shaped magnetic poles protruding from the base and formed in the circumferential direction is formed by compressing magnetic powder, and the stator is disposed so as to face the molded body. An electric motor configured such that the claw-shaped magnetic pole of another molded body is positioned between the claw-shaped magnetic poles of one molded body,
The molded body is an electric motor having a plurality of concave shapes into which positioning protrusions are inserted between the claw-shaped magnetic poles on the inner peripheral side of the base portion.   The electric motor according to claim 1, wherein a protrusion provided on the mold is inserted into the concave shape. An annular molded body in which magnetic powder is compressed is provided to face each other, the molded body has a plurality of claw-shaped magnetic poles in the circumferential direction, and between the claw-shaped magnetic poles of one molded body. In the manufacturing method of the electric motor configured so that the claw-shaped magnetic pole of the other molded body is located in the
In the step of holding and molding the molded body with the upper and lower molds and engaging the protrusions provided on the upper and lower molds with the engaging portions provided on the molded body, A method for manufacturing an electric motor, comprising positioning in a circumferential direction. A stator core having an annular base and a plurality of claw-shaped magnetic poles protruding from the base and formed in the circumferential direction is formed by compressing magnetic powder, and the stator is disposed so as to face the molded body. A method of manufacturing an electric motor configured such that a claw-shaped magnetic pole of another molded body is positioned between the claw-shaped magnetic poles of one molded body,
In the step of resin molding by holding the molded body with the upper and lower molds, the protrusion provided on the upper and lower molds and the concave shape provided on the inner peripheral side of the base and between the claw-shaped magnetic poles are engaged. A manufacturing method of an electric motor characterized by combining.

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