JP2012005211A - Rotary electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive rotary electric machine having a new bearing holding member to support a bearing.SOLUTION: A rotary electric machine includes a stator in which a winding is applied to a plurality of main poles of a stator core and a rotor rotatably provided through an air gap in the stator, and holds a bearing which supports a rotor shaft of the rotor by bearing holding members formed by molding a resin. The bearing holding member comprises: a toric base part fitted in the inside of the main poles at an axial direction end of the stator core; a step part defining a fitting depth between the base part and the main pole; a cylindrical inlay part protruding from a motor cover in an output side; and a bearing holding cylinder part holding the bearing. Each of the bearing holding members is symmetrically arranged at each side of the stator core in an axial direction of the stator core.

Description

  The present invention relates to a rotating electrical machine such as a stepping motor including a stator formed by winding a plurality of main poles that are wound poles, and a rotor that is rotatably disposed inside the rotor.

  2. Description of the Related Art Conventionally, stepping motors have been widely used in driving parts including information equipment fields such as printers, facsimiles, and copying machines, and industrial equipment fields such as FA equipment. In recent years, the total demand for stepping motors has been increasing year by year, and their applications have been widespread. Accordingly, there has been an increasing demand for compact motor design and cost reduction that can contribute to the equipment side. Small, inexpensive, high-speed, high-torque, and low-vibration rotations are required for rotating electrical machines such as stepping motors.

  As this type of stepping motor, for example, in the case of a hybrid type using a magnetic body and a permanent magnet for the rotor, ones having a configuration shown in Japanese Patent Laid-Open No. 3-212149, Japanese Utility Model Laid-Open No. 55-24020, etc. are frequently used. ing. In other words, a stator is formed by winding a plurality of main poles that protrude radially inward from an annular magnetic body frame, and a shaft is formed between the pair of magnetic bodies via an air gap. A hybrid rotor formed by sandwiching a permanent magnet magnetized in the direction is opposed to each other.

  In the stepping motor described above, a step angle of 1.8 ° is often used. However, in order to maintain and control the step angle with high accuracy, a step angle between the stator and the rotor is used. It is required to manage the air gap of 0.05 mm, for example. For this reason, a metal bush such as aluminum is fixed to a motor case that supports the stator, a ball bearing is held on the bush, and the rotor shaft of the rotor is rotated and supported with high precision by the ball bearing. Yes.

  On the other hand, in the prior art, a structure in which a metal bearing boss is welded and fixed is formed of a conductive resin having a plurality of protrusions, and the bearing boss is sandwiched between a stator and a motor cover. -95817.

JP-A-3-212149 Japanese Utility Model Publication No. 55-24020 Japanese Patent Publication No. 6-95817

  However, in the conventional configuration described above, a metal bush or a ball bearing is used to secure a minute air gap between the stator and the rotor. 1 and Patent Document 2 use a metal bracket or end cap as a metal bush, and the bracket or end cap needs to be processed as a metal bush. There is a problem of high costs. Moreover, in the thing of patent document 3, it is the structure where a resin-molded bearing boss is sandwiched between the stator and the motor cover, and the motor cover has a simple structure and realizes a relatively inexpensive configuration. Inlays and the like are still formed on the cover, and there is a problem that the cost is still high, such as ensuring the accuracy of the inlay.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to obtain a rotating electrical machine such as a stepping motor that is inexpensive and has a simplified motor cover.

  In order to achieve the above object, in the rotating electrical machine of the present invention, a stator core comprising a substantially annular core back portion and a plurality of main poles radially inwardly projecting from the core back portion. A stator that is wound around the main pole of the stator core, a rotor that is rotatably provided inside the stator via an air gap, and both axial sides of the stator In a rotary electric machine comprising: a bearing holding member that holds a bearing that rotatably supports a rotor shaft of each rotor; and a motor cover that covers at least both axial sides of the stator. Is formed by resin molding, and an annular base portion formed with an outer diameter substantially equal to the inner diameter of the main pole of the stator core and fitted inside the main pole at the axial end of the stator core, Attached surface abuts against end face of stator core The base portion defines the fitting depth of the base portion to the main pole, the cylindrical protruding portion protruding in the axial direction on the base portion and protruding from the motor cover on the motor output side, and the base portion It is provided with a bearing holding cylinder part that protrudes in the axial direction on the inner peripheral part and holds the bearing inside, and the outer peripheral surface of the base part, the outer peripheral face of the spigot part, and the inner peripheral face of the bearing holding cylindrical part are concentric. The bearing holding member is formed symmetrically on both sides in the axial direction of the stator core.

It is preferable that the above-described bearing holding member is integrally provided with a cylindrical mounting support portion that is continuous with the stepped portion so that a part of the motor cover abuts against the end surface of the mounting support portion. A cylindrical metal bearing may be used, and a cover portion may be integrally provided on the end edge of the bearing holding cylinder portion of the bearing holding member so as to cover the end surface of the metal bearing.

Alternatively, a plurality of inductor teeth may be provided at the tips of the main poles of the stator core, and the bearing holding member may be supported by fitting its base portion to the inner diameter of the inductor teeth.

Further, the rotor is sandwiched between a pair of rotor magnetic poles made of a magnetic material and having a plurality of magnetic teeth formed on the outer peripheral surface at an equal pitch on the rotor shaft, and is attached in the axial direction. It is preferable to support and constitute a rotor element composed of a magnetized permanent magnet. In this case, the magnetic teeth of the pair of rotor magnetic poles are arranged with a 1/2 pitch shift in the circumferential direction.

  Since the bearing holding member for holding the bearing is formed by resin molding, the cost of parts can be reduced as compared with a conventional product that employs a metal bearing bush. In addition, the bearing holding member has not only a bearing holding cylinder portion for fitting and holding the bearing, but also a base portion and a step portion for attachment to the axial end portion of the stator core. The mounting accuracy can be increased while facilitating the mounting work on the core. In addition, the bearing holding member has a cylindrical spigot part that can be used as a motor spigot by protruding from the motor cover on the motor output side. It is sufficient to provide only an opening, which can facilitate the simplification of the cover structure and contribute to further cost reduction.

  Further, if the mounting support portion is integrally provided on the bearing holding member, the bearing holding member attached to the stator core can be prevented from coming off by bringing the motor cover into contact with the end face. Secure attachment of the holding member is realized.

It is a cutting front view showing the rotary electric machine by one embodiment of the present invention. It is a top view of the rotary electric machine of FIG. It is a top view which shows the positional relationship of the stator and rotor of FIG. The bush of FIG. 1 is shown, (a) is a front view, (b) is a cutting | disconnection front view. FIG. 3 is a partial front view of the rotating electrical machine of FIG. 1 as viewed from the X arrow of FIG. 2. It is an enlarged view of FIG. 5, (a) is a front view, (b) is a cut side view. It is a cutting | disconnection front view which shows the rotary electric machine by other embodiment of this invention. The bush of FIG. 7 is shown, (a) is a front view, (b) is a cut front view, (c) is a perspective view. It is a cutting | disconnection front view which shows the rotary electric machine by further another embodiment of this invention.

  An embodiment of a rotating electrical machine according to the present invention will be described below with reference to the drawings.

  1 and 2 show the overall configuration of a two-phase hybrid (HB) type stepping motor as an example of the rotating electrical machine of the present invention, FIG. 1 is a cut front view, and FIG. 2 is a plan view. FIG. 3 shows the configuration of the main part of the motor, and is a view of a combination of a stator with a main pole number of 8 and an HB-type rotor as seen from the axial direction. Although omitted, each neck portion, which is a winding pole of 8 main poles, is wound, and windings wound around every other 4 main poles are connected to form one phase. Then, the remaining four main poles form another one-phase portion to form a two-phase winding as a whole. The stator is an example of adopting an 8-main pole structure excellent in high speed without generating unbalanced electromagnetic force.

  The stator 10 has an annular core back portion 12a having a substantially regular quadrilateral outer shape, and eight main poles 12b that are radially inwardly protruded from the core back portion 12a and arranged at equal intervals in the circumferential direction. The stator core 12 is composed of two-phase windings 14 (shown in FIG. 1) wound around the main poles 12b, and upper and lower insulating members interposed between the main poles 12b and the windings 14. 16 and 18, and three inductor teeth 12c project from the tip of each main pole 12b which is a wound pole. In each main pole 12b, the three inductor teeth 12c are arranged at equal intervals and at symmetrical positions with respect to the center line of the main pole 12b.

The stator core 12 is configured by laminating a plurality of silicon steel plates. As shown in FIG. 3, four main poles 12b arranged on two lines perpendicular to each other on the vertical axis (X axis) and the horizontal axis (Y axis), that is, four main poles arranged every 90 °. The pole 12b constitutes one phase (A phase, C phase), and the remaining four mechanical angles are separated from each other by 90 ° and are separated from the main pole for one phase by a mechanical angle of 45 degrees. The pole 12b forms two phases (B phase and D phase). In each phase, the four main poles 12b every 90 ° are excited and driven so as to have different polarities alternately when the winding 14 is energized.

  As shown in FIG. 1, insulating members 16 and 18 are incorporated into the stator core 12 so as to sandwich and cover the neck portions of the main poles 12 b, that is, the winding portions, from both sides in the axial direction. It is wound around each main pole 12b via these insulating members 16,18.

  On the other hand, as shown in FIG. 1, the rotor 20 disposed inside the stator core 12 includes two disk-shaped rotor magnetic poles 24 </ b> A and 24 </ b> B fixed to the rotor shaft 22 side by side in the axial direction. The disc-shaped permanent magnet 26 is sandwiched between the rotor magnetic poles 24A and 24B and is magnetized in the axial direction. Each of the rotor magnetic poles 24A and 24B is configured by laminating silicon steel plates and the like, and a plurality (22 in this embodiment) of magnetic teeth 25 are provided at equal intervals on the outer periphery thereof. . The pair of rotor magnetic poles 24A and 24B are arranged with a tooth pitch shifted by ½, and the hybrid rotor element 28 is constituted by the two rotor magnetic poles 24A and 24B and the permanent magnet 26 sandwiched therebetween. Is configured. A knurled portion 22a is provided at a position corresponding to the rotor magnetic poles 24A and 24B of the rotor shaft 22, and the rotor shaft 22 is press-fitted and fixed to a pair of rotor magnetic poles 24A and 24B sandwiching the permanent magnet 26. In the processed portion 22a, the rotor magnetic poles 24A and 24B are prevented from rotating and are firmly fixed. The permanent magnet 26 is composed of, for example, a ferrite magnet. Of course, other magnet materials such as rare earth magnets such as neodymium can also be used.

Since the number of teeth of the magnetic teeth 25 of the rotor magnetic poles 24A and 24B is 22, the rotor magnetic tooth pitch is 360 ° / 22 = 16.36 °, and the step angle is a two-phase machine. The value is equally divided and is 4.09 °. That is, this motor is of the HB type, and as is clear from the above, if one rotor magnetic pole 24A shown in FIG. The magnetic teeth 25 of the other rotor magnetic pole 24 </ b> B magnetized to the N pole are separated from each other in the axial direction by the thickness of the permanent magnet 26. Accordingly, the pitch between the N pole and the S pole of the magnetic teeth 25 as the rotor element 28 is 8.18 °, and the value obtained by dividing this value by the number of phases is the step angle, so this embodiment is a two-phase machine. The step angle is 4.09 ° as described above.

In FIG. 1, an upper cover 30 and a lower cover 32 are disposed on both axial sides of the stator 10 (referred to as an upper side and a lower side for convenience), and the outer periphery of the motor together with the outer peripheral surface of the stator core 12 of the stator 10. Covers the surface. The outer shapes of the covers 30 and 32 are each formed in a substantially regular quadrilateral shape like the stator core 12. The lower cover 32 includes a bottom plate portion 32a constituting a bottom surface, a quadrilateral outer frame portion 32b, and an inner frame portion 32c formed concentrically with the rotor shaft 22, and is integrally formed with a resin such as PPS or PBT. Has been. The lower cover 32 is fixed to the stator 10 in a state where the end surface of the outer frame portion 32 b is in contact with the lower surface of the stator core 12. As this fixing method, for example, a part of the lower insulating member 18 and a part of the lower cover 32 are closely opposed to each other over a plurality of locations on almost the entire circumference, and ultrasonic waves are applied between them to melt them. They are fixed by so-called ultrasonic welding. The lower cover 32 covers the insulating member 18 and the winding 14 that are led out from the lower surface of the stator core 12.

  A terminal portion for connection to the outside is provided on one side of the lower cover 32 described above. That is, as shown in FIGS. 1 and 2, a part of the outer frame portion 32b of the lower cover 32 is cut out, and a receiving portion 32d extending laterally is formed on the bottom plate portion 32a at this position. A circuit board 36 is attached to the insulating member 18 on the lower side of the stator core 12 by using a pin (a pallet pin) that is implanted in the stator core 12 and protrudes downward, and the end of the winding 14 is attached to the pin. Is electrically connected to the circuit board 36 by being soldered. A part of the circuit board 36 is led out from the outer surface of the stator core 12 and supported by the receiving portion 32d of the lower cover 32. A connector 38 is attached on the circuit board 36 at this position, and the circuit board 36 is electrically connected. It is connected to the. Therefore, by supplying an external power source and signals using this connector 38, the winding 14 can be energized and controlled.

The upper cover 30 is formed by press-molding a thin metal plate, and includes a top plate portion 30a and a quadrilateral outer frame portion 30b. The center portion of the top plate portion 30a includes a lower cover 32. An opening 30c having an inner diameter substantially equal to the inner diameter of the inner frame portion 32c is formed. The upper cover 30 is fixed to the stator core 12 by a caulking technique, which will be described later, with the lower end surface of the outer frame portion 30b in contact with the upper surface of the stator core 12. On the top surface of the top plate portion 30a, a mounting plate 34 having substantially the same outer shape as that formed by stamping a metal plate with a press is fixed by, for example, spot welding. The mounting plate 34 also has an opening 34a at the center thereof that matches the opening 30c of the top plate 30a.

  As is apparent from FIG. 3, axial through holes 12 d are formed at the four corners of the stator core 12 at rotationally symmetric positions every 90 °. The upper cover 30 and the lower cover 32 are each provided with an insertion hole corresponding to the through hole 12d, and the mounting plate 34 is formed with a screw hole 34b corresponding to the insertion hole. The motor is attached by, for example, screwing bolts passed through the through holes 12 d and the insertion holes into the screw holes 34 b of the mounting plate 34.

  Bearing bushes 40A and 40B are attached to inner peripheral portions on both axial sides of the stator core 12, and metal bearings 42A and 42B for rotatably supporting the rotor shaft 22 are held on the bushings. The bearing bushes 40A and 40B are of the same shape and are formed of a resin such as PPS, and have a structure as shown in FIG. That is, a stepped fitting portion 40b having an outer diameter substantially equal to the inner diameter of the inductor teeth 12c in each main pole 12b of the stator core 11 is formed at the lower portion of the annularly formed main body portion 40a. A cover support surface 40c is formed on the end surface of the outer peripheral portion of 40a, an inlay portion 40d protruding outward in the axial direction is provided inside the cover support surface 40c, and a bearing holding surface is provided on the inner periphery of the main body portion 40a. 40e is formed, and the cover part 40f extended inwardly is provided in the spigot part 40d side of this bearing holding cylinder surface 40e. The outer peripheral surface of the fitting portion 40b, the outer peripheral surface of the spigot portion 40d, and the bearing holding surface 40e are formed concentrically.

  Metal bearings 42A and 42B are fixed to the bearing holding surfaces 40e of the both bearing bushes 40A and 40B by press fitting inside. Both bearing bushes 40A and 40B are attached to the stator core 12 from both sides in the axial direction with the respective fitting portions 40b facing each other. That is, the fitting portions 40b of the bearing bushes 40A and 40B are fitted to the inner diameters of the inductor teeth 12c in the main poles 12b of the stator core 12, and the respective stepped surfaces are used as the end faces of the stator core 12. The bearing bushes 40A and 40B are attached to each other by being brought into contact with each other, and the alignment of the bearing bushes 40A and 40B with respect to the stator core 12 is performed by the fitting surface (outer peripheral surface) of the fitting portion 40b. It will be regulated by the surface. The metal bearings 42A and 42B are oil-impregnated sleeves obtained by impregnating a sintered porous metal with a lubricant, for example.

  The lower bearing bush 40 </ b> B is simultaneously fixed by fixing the lower cover 32 to the stator core 12. That is, when the bearing bush 40B is attached by fitting its fitting portion 40b inside each main pole 12b of the stator core 12, the main body portion 40a is fitted to the inner peripheral surface of the lower insulating member 18. The lower case 32 is disposed below the stator 10 in this state. At this time, when the upper end surface of the outer frame portion 32b of the lower case 32 comes into contact with the lower surface of the stator core 12, the upper end surface of the inner frame portion 32c of the lower case 32 comes into contact with the mounting support surface 40c of the bearing bush 40B. . Then, by fixing the lower cover 32 to the insulating member 18 by ultrasonic welding, a state in which the bearing bush 40 </ b> B partially fitted and held in the stator core 12 is sandwiched between the stator core 12 and the lower cover 32. And is securely fixed. The inlay portion 40 d of the lower bearing bush 40 </ b> B is loosely fitted into the inner frame portion 32 c of the lower cover 32, and the tip thereof is accommodated in the inner frame portion 32 c without being led out from the lower cover 32.

  The upper bearing bush 40 </ b> A is attached to the stator core 12 after the rotor 20 is incorporated into the stator 10, and is fixed simultaneously by fixing the upper cover 30 to the stator 10. That is, the rotor 20 is inserted into the inner side of the stator core 12 of the stator 10 to which the lower bearing bush 40B and the lower cover 32 are fixed, and the lower portion of the rotor shaft 22 of the rotor 20 is connected to the bearing bush 40B. The rotor magnetic poles 24 </ b> A and 24 </ b> B of the rotor 20 are inserted into the inner side of the held metal bearing 42 </ b> B so as to face the inner surfaces of the main poles 12 b of the stator core 12. Thereafter, the bearing bush 40A holding the metal bearing 42A is inserted into the metal bearing 42A from the upper end of the rotor shaft 22 with the fitting portion 40b facing downward, and the fitting portion 40b is inserted into the stator. The core 12 is fitted inside the main pole 12b. After the fitting portion 40 b of the bearing bush 40 </ b> A is fitted to the stator core 12, the upper cover 30 is fixed to the stator core 12.

  When the upper cover 30 is fixed to the stator core 12, the lower end surface of the outer frame portion 30b of the upper cover 30 is brought into contact with the upper surface of the stator core 12, and at the same time, the upper cover is attached to the mounting support surface 40c of the bearing bush 40A. Since the 30 top plate portions 30a come into contact with each other, the bearing bush 40A is sandwiched between the stator core 12 and the upper cover 30 and is securely fixed. At this time, the spigot portion 40d of the bearing bush 40A is loosely inserted into the opening 30c of the top plate portion 30a of the upper cover 30 and the opening 34a of the mounting plate 34, as shown in FIG. Projects from the top surface. Therefore, by using the lead-out portion of the inlay portion 40d, the rotor shaft 22 can be accurately matched with the input portions of various devices when the motor is attached to various devices.

  Next, the fixing of the upper cover 30 to the stator 10 will be described. As described above, the quadrilateral upper cover 30 has the top plate portion 30a and the outer frame portion 30b. However, the fixing piece 30d as shown in FIG. 5 is integrated with the outer frame portion 30b corresponding to the four corners of the quadrilateral. And extended downward. As clearly shown in FIG. 6A, a hole 30e is provided near the lower portion of the fixed piece 30d, and a portion below the hole 30e of the fixed piece 30d is a caulking action portion 30f. Two tapered surfaces 30e1 and 30e2 are formed on the inner lower edge of the punch hole 30e so that the center position is lowest. At the position of the stator core 12 corresponding to the lower portion of the fixed piece 30d, a concave portion 12e opening in a rectangular shape is provided on the outer surface. Here, the upper edge of the recess 12e is partially crossed with the tapered surfaces 30e1 and 30e2 of the hole 30e of the fixing piece 30d when the lower end surface of the outer frame portion 30 of the upper cover 30 is in contact with the upper surface of the stator core 12. It is set to such a height.

  When the upper cover 30 is fixed to the stator 10, as described above, the upper bearing bush 40A is attached to the stator core 12, and then the upper cover 30 is placed on the stator core 12 with the outer frame portion 30b. Are arranged in contact with the upper end surface of the stator core 12, and then the central portions of the action portions 30f of the respective fixing pieces 30d located at the four corners of the upper cover 30 are directed from the outside to the inside. The upper cover 30 is caulked and fixed by stamping, that is, a part of the action portion 30f is deformed and inserted into each of the recesses 12e.

  At this time, part of the action portion 30f of the fixed piece 30d enters the concave portion 12e of the stator core 12 to prevent the upper cover 30 from being detached and prevented from falling off. In the case of the structure of the present embodiment, the upper cover is particularly preferable. 30 strong fixations are realized. That is, as can be seen from FIGS. 6A and 6B, the tapered surfaces 30e1 and 30e2 of the lower edge of the punch hole 30e in the fixed piece 30d, that is, the upper edge tapered surface of the action portion 30f is the concave portion 12e of the stator core 12. When the action portion 30f is deformed into the recess 12e, a downward pulling force is generated in the fixed piece 30d as the upper edge tapered surface of the action portion 30f enters the recess 12e. As a result, the upper cover 30 can be pressed against the stator core 12, and the pressing forces act at the four corners of the upper cover 30, and the entire upper cover 30 can be firmly fixed to the stator core 12.

  In the stepping motor having the above-described configuration, the step angle that can be rotated by the pulse signal is set to 4.09 °, and the rotation angle is set larger than that of the general 1.8 °. Therefore, it can be rotated at this speed. That is, it can be said that the embodiment is a stepping motor capable of increasing the speed. Since the output of the motor is proportional to the product of the rotation speed and the torque, the output increases as a result of this increase in speed, resulting in increased efficiency.

  On the other hand, unlike the conventional stepping motor, metal bearings 42A and 42B are used as bearings for the rotor 20 in the stepping motor described above. Since these types of metal bearings 42A and 42B are so-called sliding bearings, the air gap between the stator and the rotor is set to be slightly larger than the air gap in the case of a ball bearing. In this case, the air gap between the stator and the rotor affects the efficiency of the motor, and the efficiency tends to decrease as the air gap increases. However, in the above embodiment, since the speed is increased and the efficiency is increased by setting the step angle, even if the metal bearings 42A and 42B are used as the bearings, the efficiency decreases. As a result of improving the efficiency only to compensate, a stepping motor that exhibits an efficiency equal to or higher than the conventional case can be obtained.

  Here, the stator core 12 is configured by laminating a predetermined number of silicon steel plates, and adopts a method of laminating the silicon steel plates that are press-punched into a predetermined shape one after another by 90 °. As a result, it is possible to obtain the effect of suppressing variation in the permeance vector. That is, since the stator core 12 shown in FIG. 3 has a 90 ° point symmetrical structure, the permeance vector due to a slight difference in the size of the punching die or a difference in the thickness of the silicon steel plate can be obtained by rotating and overlapping the 90 °. This variation can be canceled.

  Next, Embodiment 2 of the present invention will be described with reference to FIGS. 7 and 8, the same reference numerals as those described above indicate the same or corresponding ones. In FIG. 7, the metal bearings 42A and 42B that rotatably support the rotor 20 are supported by bearing bushes 40A ′ and 40B ′ that are configured by resin molding and whose resin material is set to an optimum usage amount. It is what you do.

  That is, the bearing bushes 40A 'and 40B' are formed of a resin such as PPS and have a structure as shown in FIG. That is, an annular base portion 40a ′, which is a main body portion having an outer diameter substantially equal to the inner diameter of the inductor teeth 12c in each main pole 12b of the stator core 11, and a stepped fitting formed on the outer peripheral portion. A portion 40b, a cylindrical mounting support tube 40g extending upward from the fitting portion 40b and having a cover support surface 40c formed on the end surface thereof, and concentric with the inner surface of the mounting support tube 40g on the upper surface of the base portion 40a ′. A cylindrical inlay portion 40d 'protruding in a shape, a bearing holding cylinder 40h extending upward on the upper surface of the inner peripheral portion of the base portion 40a' and having a bearing holding surface 40e formed on the inner periphery thereof, and this bearing holding And a cover portion 40f extending inward from the upper end of the tube 40h.

  Metal bearings 42A and 42B are fixed to the bearing holding surfaces 40e of both bearing bushes 40A 'and 40B' by press-fitting. Both bearing bushes 40A 'and 40B' are attached to the stator core 12 from both axial sides with the respective base portions 40a 'facing each other. That is, the fitting portions 40b of the bearing bushes 40A ′ and 40B ′ are fitted to the inner diameters of the inductor teeth 12c in the main poles 12b of the stator core 12, and the stepped surfaces of the fitting portions 40b are formed. The bearing bushes 40A ′ and 40B ′ are attached by being brought into contact with the end surface of the stator core 12, and the alignment of the bearing bushes 40A ′ and 40B ′ is performed by the fitting portion 40b, and the axial position is regulated by the stepped surface. become.

The lower bearing bush 40 </ b> B ′ is simultaneously fixed by fixing the lower cover 32 to the stator core 12. The upper end surface of the inner frame portion 32c of the lower case 32 comes into contact with the mounting support surface 40c of the bearing bush 40B '. Then, by fixing the lower cover 32 to the stator 10, the bearing bush 40 </ b> B ′, a part of which is fitted and held in the stator core 12, is sandwiched between the stator core 12 and the lower cover 32. Fixed to.

Further, when the upper cover 30 is fixed to the stator core 12, the top plate portion 30a of the upper cover 30 comes into contact with the mounting support surface 40c of the bearing bush 40A ', and the bearing bush 40A' is fixed to the stator core 12 and the upper cover 30. And is securely fixed. At this time, the spigot portion 40 d of the bearing bush 40 </ b> A ′ is loosely inserted into the opening 30 c of the top plate portion 30 a of the upper cover 30 and the opening 34 a of the mounting plate 34, and its upper end protrudes from the upper surface of the mounting plate 34. Therefore, by using the lead-out portion of the inlay portion 40d, the rotor shaft 22 can be accurately matched with the input portions of various devices when the motor is attached to various devices.

  Next, Embodiment 3 of the present invention will be described with reference to FIG. In FIG. 9, the same reference numerals as those described above indicate the same or corresponding ones. The structure shown in FIG. 9 employs a so-called twin magnet type rotor 20 'and uses a stator 10' matched to the axial length of the rotor 20 '.

  That is, the stator 10 ′ is different from the one shown in FIG. 1 in a stator core 12 ′ configured by laminating a plurality of silicon steel plates. The shaft length is formed. In this case as well, by adopting a method in which silicon steel plates that have been punched into a predetermined shape are successively rotated by 90 ° and laminated, variations in permeance vectors can be eliminated and balanced.

The rotor 20 ′ is an HB type rotor configured by using a rotor element in which a permanent magnet is sandwiched between a pair of rotor magnetic poles, but in this embodiment, two rotor elements 28X and 28Y are used. It is comprised using. That is, the rotor 20 ′ includes four disk-like rotor magnetic poles 24AX, 24BX, 24BY, and 24AY that are fixed to the rotor shaft 22 ′ in the axial direction, and between the pair of rotor magnetic poles 24AX and 24BX and 24BY. , 24AY and disk-shaped permanent magnets 26X, 26Y magnetized in the axial direction. Each of these rotor magnetic poles is formed by laminating silicon steel plates and the like, and a plurality (22 in this embodiment) of magnetic teeth 25X and 25Y are provided on the outer periphery of each of the rotor magnetic poles.

The pair of rotor magnetic poles 24AX, 24BX are arranged with a tooth pitch offset by 1/2, and a permanent magnet 26X is sandwiched between them. Similarly, the pair of rotor magnetic poles 24AY, 24BY have a tooth pitch of 1 / The permanent magnets 26Y are sandwiched between the two. The permanent magnets 26X and 26Y are set so that the magnetization directions are opposite to each other. The rotor magnetic poles 24AX and 24BX magnetized by the permanent magnet 26X and the rotor magnetic poles 24AY and 24BY magnetized by the permanent magnet 26Y Among them, the adjacent rotor magnetic poles 24BX and 24BY facing each other are set to have the same polarity. At this time, the tooth positions in the circumferential direction of the adjacent rotor magnetic poles 24BX and 24BY are the same position. The rotor magnetic poles 24AX and 24BX and the permanent magnet 26X constitute a rotor element 28X, and the rotor magnetic poles 24AY and 24BY and the permanent magnet 26Y constitute a rotor element 28Y. Although FIG. 7 shows a state where the rotor elements 28X and 28Y are adjacent to each other without a gap, the rotor elements 28X and 28Y may be adjacent to each other with a slight separation in the axial direction.

  The magnetic teeth 25X, 25Y of the rotor magnetic poles 24AX, 24AY, 24BX, 24BY of the rotor elements 28X, 28Y are opposed to the inductor teeth of the main poles of the stator 10 'in the radial direction via air gaps. To do. A rotor 20 ′ in which two rotor elements 28X and 28Y are supported by a common rotor shaft 22 ′ has bearing bushes 40A ′ and 40B ′ in which the rotor shaft 22 ′ is provided on both axial sides of the stator 10 ′. Are supported by the metal bearings 42A and 42B. The bearing bushes 40A 'and 40B' are attached to the stator 10 'by fixing the upper cover 30 and the lower cover 32 to the stator 10' as in the second embodiment. A knurled portion 22a 'is formed at an appropriate position on the rotor shaft 22' in order to firmly fix each rotor magnetic pole.

  The rotating electrical machine according to the present invention is capable of high-speed rotation, achieves high efficiency, and can reduce the cost by adopting a metal bearing. As a stepping motor, it can be used for copying machines and printers that are OA devices. On the other hand, it is possible to provide an inexpensive, high-speed, high-torque, low-vibration rotating electrical machine, which is expected to make a significant industrial contribution. In addition, application to medical equipment, FA equipment, robots, amusement machines, and housing equipment is also highly expected.

10, 10 ': Stator 12, 12': Stator core 12b: Main pole 12c: Inductor teeth 14: Winding 20, 20 ': Rotor 22, 22': Rotor shafts 24A, 24B, 24AX, 24BX , 24AY, 24BY: Rotor magnetic poles 25, 25X, 25Y: Magnetic teeth 26, 26X, 26Y: Permanent magnets 28, 28X, 28Y: Rotor element 30: Upper cover 32: Lower cover 40A, 40A′40B, 40B ′: Bearing bush 40a: Main body portion 40a ': Base portion 40b: Stepped fitting portion 40c: Mounting support surface 40d: Inner portion 40e: Bearing holding surfaces 42A, 42B: Metal bearing

Claims (5)

A substantially annular core back portion, a stator core composed of a plurality of main poles projecting radially inwardly from the core back portion, and a winding wound around the main pole of the stator core Including a stator,
A rotor provided rotatably inside the stator via an air gap;
Bearing holding members that are arranged on both sides of the stator in the axial direction and hold bearings that rotatably support the rotor shaft of the rotor;
In a rotating electrical machine comprising a motor cover that covers at least both axial sides of the stator,
The bearing holding member is formed by resin molding, and the outer diameter of the bearing holding member is substantially equal to the inner diameter of the main pole of the stator core and is fitted inside the main pole at the axial end of the stator core. A mating portion, a stepped surface that defines a fitting depth of the fitting portion to the main pole by contact with the end surface of the stator core, and a protruding tip portion on the motor output side A cylindrical spigot portion led out from the motor cover and a bearing holding surface for holding the bearing are formed, and the outer peripheral surface of the fitting portion, the outer peripheral surface of the spigot portion, and the bearing holding surface are formed concentrically. And the said electric bearing holding member is symmetrically arrange | positioned in the axial direction both sides of the said stator core, The rotary electric machine characterized by the above-mentioned. 2. The rotating electrical machine according to claim 1, wherein the bearing holding member is provided with an attachment support surface on the outer peripheral end surface of the main body portion, with which a part of the motor cover abuts. A cylindrical metal bearing is used as the bearing, and a cover portion is integrally provided at an axial end portion of the bearing holding surface of the bearing holding member so as to cover the end surface of the metal bearing. The rotating electrical machine according to claim 1 or 2. A plurality of inductor teeth are provided at the tips of the main poles of the stator core, and the bearing holding member is supported by fitting its base portion to the inner diameter of the inductor teeth. The rotating electrical machine according to claim 1. The rotor is sandwiched between a pair of rotor magnetic poles made of a magnetic material and having a plurality of magnetic teeth formed on the outer peripheral surface at an equal pitch on the rotor shaft, and is attached in the axial direction. A rotor element comprising a magnetized permanent magnet is supported, and the pair of rotor magnetic poles are arranged such that their magnetic teeth are displaced by 1/2 pitch in the circumferential direction. The rotating electrical machine according to claim 4.

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