JP2014050215A - Divided stator core component in electric motor having can structure, stator core using the same and electric motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stator core in which, when divided stator core components are assembled to form a stator core, efficiency of an electric motor is not influenced by a manufacturing error of each stator core component.SOLUTION: Stator core components are used for constituting a stator core of an electric motor. The stator core component includes: a partial cylindrical part having a partial cylindrical shape; and a tooth part toward the center of the stator core from this partial cylindrical part. Both ends of the partial cylindrical part have a joint shape corresponding to the end of another partial cylindrical part neighboring, and the joint shape should be a wave form curve shape along the radial direction of the stator core.

Description

  The present invention relates to a stator core of an electric motor, and more particularly to a divided stator core component in an electric motor having a can structure, a stator core using the stator core component, and an electric motor.

  Conventionally, a vacuum pump as shown in FIG. 1 is known, and this vacuum pump is provided with an electric motor 15 for rotationally driving a pump main shaft 20. Such a vacuum pump is widely used, for example, for exhausting process gas in a vacuum chamber in a semiconductor manufacturing process. The electric motor 15 shown in FIG. 1 has a structure in which the motor rotor 40 is directly connected to the pump main shaft 20. For this reason, for structural reasons, the motor rotor 40 in the rotor chamber 19 may contact the process gas leaked from the pump chamber. Since the process gas used in semiconductor manufacturing is corrosive, the motor rotor 40 and the like are manufactured from a material having corrosion resistance.

  On the other hand, the motor stator 100M also needs to be protected from corrosion due to contact with the process gas. As a method for protecting against corrosion, there is an example in which a can 17 is provided between the motor rotor 40 and the motor stator 100M in addition to an example in which the entire motor stator is sealed with resin. Here, the can 17 is a cylindrical member for isolating the motor rotor 40 and the motor stator 100M. Thus, the electric motor having a structure in which the motor rotor 40 and the motor stator 100M are separated by the can 17 is referred to as a canned motor. Note that an operation control device 140 is connected to the electric motor 15.

  In order to make the electric motor into a can structure, a metal can may be installed on the inner periphery of the stator core. Originally, it is desirable that the can be accurately assembled with the inner peripheral surface and the outer peripheral surface of the can and assembled on the inner peripheral surface of the stator core whose dimensions are controlled by machining. However, in actual can manufacturing, a thin can plate is not manufactured by machining, but a thin metal plate is often manufactured by cylindrical bending and seal welding. In this manufacturing method, it is very difficult to manufacture by “shrink fitting” or “without a gap”. For this reason, when manufacturing a canned motor using a metal can, after the can is inserted into the stator core, the metal can is expanded and brought into close contact with the inner peripheral surface of the stator core having a relatively high mechanical dimensional accuracy. The process is often performed. By performing this processing, the inner peripheral surface dimension of the stator core and the metal can dimension can be managed, and the separation distance (gap dimension) between the motor rotor and the motor stator can be accurately managed. Further, the separation distance between the motor rotor and the motor stator must be designed and manufactured so as to be as small as possible. This is because the rotating magnetic field generated by the stator core increases the magnetic loss and decreases the rotor rotational force as the separation distance increases. In other words, the electromechanical conversion efficiency as an electric motor is reduced.

On the other hand, when a rotating magnetic flux is generated in a state where a metal can is installed, an eddy current is generated in the can and a loss due to the eddy current occurs. When designing an electric motor aiming at high efficiency, a can made of a non-metallic material such as resin has been selected in order to avoid the loss due to the eddy current. In the case of a resin can, since it can be manufactured by injection molding using a mold or the like, the dimensions of the inner and outer peripheral surfaces of the can can be manufactured relatively accurately. However, since the resin can is a brittle member in many cases, it is difficult to perform an extended adhesion process for installing the resin can on the inner peripheral surface of the stator core without a gap. In addition, since it is a resin member, “shrink fitting” processing is difficult. Therefore, when the resin can is employed, a gap is generated between the inner circumferential surface of the stator core and the outer circumferential surface of the resin can due to the cross dimension that cannot be avoided in machining.

  FIG. 2 is a perspective view showing the motor stator 201 and the can 209, and FIG. 3 is a view of the stator from the end face side. In FIG. 2, the center axis of the motor stator 201 is shown to be in the vertical direction. As can be seen from FIG. 2, the motor stator 201 includes a cylindrical stator main body and a teeth portion 205 extending radially inward from the stator main body. The teeth portion 205 extends from the stator main body side with a certain width, and has a shape that spreads toward the end at the tip portion that contacts the can 209. An excitation winding 207 is wound around the tooth portion 205.

  It is desirable to wind the windings 207 as densely as possible. This is because the denser the windings 207 are, the higher the magnetic density that is generated, and the higher the output efficiency of the motor as a whole. However, in the case of the cylindrical motor stator 201 with the tooth portion 205 already installed as shown in FIGS. 2 and 3, it is very difficult to tightly wind the winding 207 around the tooth portion 205. This is because the winding 207 needs to be wound in a narrow space between the teeth portions 205.

  FIG. 4 is a diagram illustrating an example for solving the above-described problem. As shown in this figure, a cylindrical motor stator 401 is divided into a plurality of portions along the circumferential direction in order to wind the winding densely and many times around the teeth portions 405-1, 405-2 and the like. ing. In this case, the motor stator 401 is composed of a plurality of stator core components (for example, 401-1 to 401-6) each having the tooth portions 405-1 to 405-6. And it becomes possible to wind as many windings as possible and densely around the teeth portions 405-1 to 405-6 of the stator core components 401-1 to 401-6 that are separated from each other. After that, such a wound stator core component is connected in the circumferential direction to form a cylindrical motor stator 401.

  The example using the divided stator core components as described above is disclosed in Patent Literature (see Patent Literature 2). In this example, in order to connect a plurality of stator core components, notches and protrusions corresponding to each other are formed at both ends of the stator core body in each stator core component. That is, a notch structure and a protrusion structure are provided at the end portions of two adjacent stator core main bodies, and the stator core components are joined to each other by fitting them together (particularly, FIG. 3 of Reference 2). And see FIG.

  By the way, as described above, in a general electric motor, it is desirable to make the separation distance between the motor stator and the motor rotor as small as possible from the viewpoint of improving the electromechanical conversion efficiency. In particular, in the case of an electric motor provided with a can 209 as shown in FIG. 2, the tip portion 2051 of the tooth portion 205 is formed on the outer peripheral surface of the can 209 in order to reduce the separation distance between the motor stator 201 and the motor rotor 203. It must be in contact. This is because if there is a gap between the end wide end portion 2051 of the teeth portion 205 and the can 209 due to a manufacturing error of the teeth portion 205, the distance from the motor rotor 203 increases correspondingly and acts on the motor rotor 203. This is because the magnetic force is reduced and the motor efficiency is reduced.

JP 2012-120268 A JP 2009-95189 A

  FIG. 4 shows a case where a gap d2 exists between the tip of the second tooth portion 405-2 and the can 409 as an example. This is a case where there is no manufacturing error in the stator core body (partial cylindrical portion) and there is a manufacturing error in the length of the teeth portion 405-2. In such a case, the distance from the motor rotor of the second tooth portion 405-2 is larger than that of the other tooth portions 405-1, and the magnetic force acting on the motor rotor is reduced.

  On the other hand, when the motor stator is assembled in a state where there is a manufacturing error in the length of the tooth portion (see FIG. 5A), a deviation occurs in the joint portion of the stator core bodies adjacent to each other (see FIG. 5 ( (See part X of b)). For example, FIG.5 (b) has shown the case where the teeth part 405-2 is slightly long compared with another teeth part. When such a shift | displacement arises, the contact area of stator core main bodies will reduce and magnetic resistance will increase. Furthermore, as shown in FIG. 6 (b), there may be a circumferential gap in the joint portion of the stator core body (see section X in FIG. 6 (b)). 410 is hindered and causes an increase in magnetoresistance.

  Further, although the invention according to Patent Document 2 is not a canned motor, the manufacturing error as described above is a serious problem. That is, if a precise fitting structure as in Patent Document 2 is used, it may be considered that the stator core cannot be completely assembled properly due to manufacturing errors. Even if assembled, it does not have a structure that corrects (or absorbs) manufacturing errors, so when applied to a canned motor, the tip of one or more teeth and the can A gap is generated between them. On the other hand, if the highest priority is given to fitting the entire stator core part using a precise fitting structure as in Patent Document 2, the tip of the teeth part does not come into contact with the can due to manufacturing errors of the stator core part. Stator core parts are generated.

  Further, the example shown in FIGS. 7 and 8 uses a fitting notch structure 710, although it is not a precise fitting structure like the invention according to the cited document 2. Also in this case, similarly to the invention of Patent Document 2, the notch portion is not properly matched, the teeth portion does not come into contact with the can 709, or both of these problems cannot be avoided. FIG. 8B shows a case where the notch portions are not properly matched (see the X portion in the figure). As shown in this figure, a radial shift and a circumferential clearance are generated at the joint portion of the stator core component 703.

  Therefore, in the present invention, even when a canned motor is manufactured, even if each of the stator core components that may have a manufacturing error is assembled, the effect of the manufacturing error does not affect the efficiency of the electric motor (the magnetic resistance is reduced). It is an object to provide a motor stator that does not increase. Especially for motor stators that use resin cans, the stator core has a split structure in order to minimize the gap between the can and the outer peripheral surface, and the structure ensures contact (adherence) to the outer peripheral surface of the can And Specifically, it is as follows.

  According to a first aspect of the present invention, there is provided a stator core component for constituting a stator core of an electric motor, the stator core component comprising: a partial cylindrical part cylindrical part; and a tooth extending from the partial cylindrical part toward the center of the stator core. Both end portions of the partial cylindrical portion have a joint shape corresponding to the end portions of other adjacent partial cylindrical portions, and the joint shape is a waveform curve along the radial direction of the stator core. The configuration is a shape.

  In the second invention, the waveform curve shape is a sine wave.

  In the third invention, the sine wave has a shape corresponding to less than a half wavelength.

  In the fourth aspect of the invention, the stator core component is formed by laminating a plurality of plate-like bodies in the central axis direction of the stator core, and has a first wavy curve shape at both end portions of the partial cylindrical portion. A configuration in which first plate-like bodies and second plate-like bodies having a second waveform curve shape obtained by inverting the first waveform curve shape are alternately arranged along the central axis direction. Is adopted.

  Further, in the fifth invention, a plurality of the first plate-like bodies are continuously arranged along the central axis direction, and a plurality of the second plate-like bodies are continuously arranged. The structure is adopted.

  In the sixth invention, a stator core formed by assembling the stator core components according to any one of the first to fifth inventions is adopted.

  Moreover, in 7th invention, the structure of the electric motor provided with the stator core which concerns on 6th invention is taken.

  Further, in an eighth aspect of the invention, the electric motor includes a cylindrical can disposed inside the stator core, and the outer diameter of the can is such that each stator core component is completely fitted with each other. The configuration of the seventh invention, which is larger than the inner peripheral diameter formed by the tip portion of the tooth portion, is adopted.

  According to the invention according to the embodiment of the present application, for example, in a canned motor, even if a manufacturing error has occurred in the stator core component, the motor stator can be assembled, and the magnetoresistance due to the presence of the manufacturing error can be reduced. An increase can be avoided.

It is a schematic sectional drawing which shows a vacuum pump provided with a canned motor. It is a perspective view which shows the structure of the stator which concerns on related technology. It is the figure seen from the end surface side of the stator disclosed in FIG. It is a perspective view which shows the stator core which consists of several stator core components based on related technology. FIG. 5 is an explanatory diagram for explaining a factor of increasing magnetoresistance due to a manufacturing error of the stator core component disclosed in FIG. 4. It is explanatory drawing explaining the other magnetoresistive increase factor resulting from a manufacturing error of the stator core component disclosed in FIG. It is the schematic which shows the stator core component with a notch based on related technology. It is explanatory drawing explaining the magnetoresistive increase factor resulting from the manufacturing error of the stator core component disclosed in FIG. It is the figure which assembled the stator core component which concerns on 1st Embodiment of this invention, and was set as the stator core, and this stator core was seen from the end surface side. It is the figure which looked at the state before an assembly of the stator core disclosed in FIG. 9 from the end face side. It is a figure which shows the stator core component which consists of a some plate-shaped object. (Example 1 of laminated steel sheet meshing structure). It is explanatory drawing explaining the principle which absorbs a manufacturing error by the stator core components disclosed in FIG. It is a figure which shows the state which fitted the adjacent stator core components and the gap | interval g has arisen. It is explanatory drawing explaining the magnetic path in the butt | matching part of the stator core component disclosed in FIG. It is a figure which shows the stator core component which consists of a some plate-shaped body based on 2nd Embodiment. (Example 2 of meshing structure of laminated steel plates). It is a figure which shows the stator core components which consist of a several plate-shaped body based on 3rd Embodiment, and is a figure which shows the case where the plate-shaped body of the same shape is continuing several sheets. (Example 3 of meshing structure of laminated steel sheets). It is explanatory drawing explaining the relationship between a fitting state and a can of the stator core component which concerns on 4th Embodiment.

First embodiment

[Overview]
With reference to FIG. 9, an overall outline of the stator core 903 according to the first embodiment of the present invention will be described. In this embodiment, the stator core 903 of the canned motor is configured by a combination of six stator core components 901, 903, 905, 907, 909, and 911 (hereinafter referred to as “901 etc.”). Here, the stator core component 901 or the like includes a partial cylindrical part cylindrical portion and teeth portions 901t, 903t, 905t, 907t, 909t, 911t (hereinafter referred to as “901t”) extending from the partial cylindrical part toward the center of the stator core 903. Etc.)).

[Partial cylindrical part]
In the stator core 903 of the present embodiment, the cylindrical stator core 903 is configured by the six stator core components 901 and the like as described above. For this reason, partial cylindrical parts, such as each stator core component 901, will occupy a part corresponding to an angle of 60 °. Both end portions (901-902) e and (911-901) e of the partial cylindrical portion have joint shapes corresponding to the end portions of other adjacent partial cylindrical portions, and the joint shape is the stator core 903. It is the waveform curve shape along the radial direction. Details of the joint shape (waveform curve shape) will be described later.

[Teeth Department]
Each stator core component 901 or the like is provided with a tooth portion 901t or the like extending toward the center of the stator core 903 in order to form a magnetic pole. The teeth portion 901t and the like of the present embodiment extend from a substantially central portion in the circumferential direction of the partial cylindrical portion. The teeth portion 901t and the like have a substantially constant width from the partial cylindrical portion side to the vicinity of the distal end portion side (side near the center of the stator core). On the other hand, tip portions such as the teeth portion 901t have a shape that spreads toward the center of the stator core 903. Further, windings 901m, 903m, 905m, 907m, 909m, and 911m (hereinafter referred to as “901m etc.”) are tightly wound around the teeth portion 901t and the like.

[Joint shape]
In the partial cylindrical portion such as the stator core component 901, joint shapes are formed at both end portions (901-902) e and (911-901) e. These joint shapes are for joining the adjacent stator core components 901 and the like mechanically (so as not to come off) and magnetically (so as not to increase the magnetic resistance). The joint shape of the present embodiment has a waveform curve shape, and more specifically a shape like a sine wave. In particular, the wavy curve shape is formed by two peaks and one valley between these two peaks if the counterclockwise direction with respect to the center of the stator core 903 is defined as the upper side of the wave. For this reason, in this embodiment, the waveform curve shape generally corresponds to a sine wave 1.5 wavelength.

  However, the waveform curve shape according to the embodiment is merely an example, and the present invention is not limited to this. That is, the waveform curve shape may be a shape corresponding to less than half wavelength, or a shape corresponding to one wavelength (one peak and one valley). Furthermore, it may be more than 1.5 wavelengths and more than 2 wavelengths (two peaks and valleys).

[State before assembly]
FIG. 10 is a diagram illustrating a state before the assembly of the stator core disclosed in FIG. 9. As shown in this figure, waveform curve shapes are formed at both ends of a partial cylindrical shape of a specific stator core component 901. The other stator core components 903 and 911 adjacent to the specific stator core component 901 have a waveform curve shape corresponding to the waveform curve shape. By the way, in FIG. 10, the waveform curve shape whose full length is a solid line and the waveform curve shape whose part is a broken line are shown in a state where they are just reversed. This point will be described in detail with reference to FIG.

  FIG. 11 is a diagram showing a joint portion between stator core components 1201 and 1202 adjacent to each other. In particular, FIG. 11A is a view corresponding to FIG. 10 (viewed from the end face direction), and FIG. 11B is a side view. In particular, as can be seen from FIG. 11B, each of the stator core components 1201 and 1202 of this embodiment has a structure in which plate-shaped steel plates are stacked in the central axis direction C of the stator core. And joining shape, such as the edge part (1201-1202) e of each plate-shaped body, is reversed for every layer adjacent to the central axis direction C. FIG. That is, the joining shape (9-1-01) of one layer of the laminated structure and the joining shape (9-1-03) of another layer adjacent to each other in the central axis direction C in the same stator core component are mutually inverted. It has become a relationship.

[Action]
Next, the operation of the stator core component according to the present embodiment will be described with reference to FIGS. In the example shown in FIG. 12, there is a manufacturing error in the length of some of the tooth portions. This is a case of deviation. Even in such a case, since both ends of the partial cylindrical part are formed in a waveform curve shape, even if they do not fit exactly, they fit gently with the waveform shape slightly shifted from each other (See the X part in FIG. 12B). Therefore, even if there is a manufacturing error (shift) between adjacent stator core components, the stator core can be assembled as a whole (see FIG. 12B). In this way, the joint strength in the central axis direction is improved in addition to the joint strength in the circumferential direction. In other words, it means that mechanical bonding is possible while maintaining a certain bonding strength.

  Simultaneously with the above, in this embodiment, in addition to the mechanical joining action, the magnetic joining action is sufficiently realized. That is, as shown in FIG. 12 (b), even when there is a deviation in the joint, at least about three places contact each other in the same layer of plate-like bodies (laminated steel plates) between the mutually adjacent stator core components. . For this reason, the increase in magnetic resistance is suppressed to some extent by this contact portion. On the other hand, as shown in FIG. 13, a predetermined gap g may be generated between the abutting surfaces of the plate-like bodies depending on the joining site. However, as shown in FIG. 14, the plate-like bodies adjacent to each other in the central axis direction C have mutually inverted shapes at the joint portion, so that the magnetic path is reliably maintained. Even with such a structure, an increase in magnetoresistance is effectively suppressed.

[Second Embodiment]
Next, a stator core component according to the second embodiment will be described with reference to FIG. The invention according to this embodiment has the same basic technical idea as the invention according to the first embodiment. However, the specific shape of the bonding shape is different. That is, at first glance, it has a simple arc shape. With such a simple arc shape, there is no problem in assembling even when the joint is displaced due to a manufacturing error. At the same time, adjacent plate-like bodies come into contact with each other at least at one place and the periphery thereof. For this reason, it is possible to ensure the mechanical joint strength. In addition, as shown in FIG. 15B, the plate-like bodies adjacent to each other in the central axis direction C are in contact with each other over a wide area, so that an increase in magnetic resistance is also suppressed.

  The “arc shape” is included in the “waveform curve shape” of the present invention. This is because if the waveform curve shape is focused on a narrow range, there is a shape that is as close as possible to an arc.

[Third Embodiment]
Next, a third embodiment will be described based on FIG. This embodiment is characterized by a laminated structure of plate-like bodies. That is, as shown in FIG. 16B, the bonding shape itself is the same as that of the first embodiment, but is different in that a plurality of plate-like bodies having the same bonding shape are continuously stacked. . Specifically, in the example shown in FIG. 16B, a set of four plate-like bodies having the same shape (first plate-like body and second plate-like body) each along the central axis direction C. It is alternated. Thereby, a rectangular-wave-like joining structure is realized. Other operations are the same as those in the first and second embodiments.

[Fourth Embodiment]
Next, a fourth embodiment will be described based on FIG. Here, FIG. 17A is a diagram showing a state in which the stator core components are completely fitted to each other. Moreover, the circle P by a virtual line has shown the outer periphery diameter of the can. The above-mentioned “stator core parts are completely fitted” means that the adjacent cylindrical parts of the stator core parts that are adjacent to each other have no gaps along the circumferential direction and no radial deviation. It is defined as a matching state. In this state, as shown in the figure, the outer peripheral diameter of the can indicated by the phantom line is larger than the inner peripheral diameter formed by the tip of each tooth portion.

  On the other hand, FIG. 17B is a diagram showing a state where the can and the stator core parts are actually combined. As can be seen from this figure, in the state where the tip of the teeth portion of each stator core component is in contact with the outer peripheral surface of the can, each stator core component is more than in the above-mentioned state in which the stator core components are completely fitted together. There will be a slight shift outward in the radial direction. For this reason, a slight gap is formed in the circumferential direction between the adjacent stator core components (see the portion X in FIG. 17B). Thus, by forming a slight gap, adjacent stator core components can move slightly in the radial direction. This means that even if a manufacturing error occurs in the stator core component (particularly, the length of the tooth portion), the manufacturing error can be absorbed and the tip portions of all the tooth portions can be brought into contact with the cans. . For example, even if the teeth part of a specific stator core part is formed slightly shorter than other teeth parts, it is possible to push it inward in the radial direction during assembly, and make all teeth parts contact the can Is possible.

  It goes without saying that a stator core using the above-described stator core component and an electric motor using this stator core are also included in the technical scope of the present invention. Each of the above features can be included in the invention alone or in any combination within the scope of the invention.

  The embodiment of the present application can be used for, for example, a combination of divided stator portions of a motor in an electric motor having a can structure used for rotational driving of a vacuum pump.

201 Motor stator 203 Motor rotor 205 Teeth portion 207 Winding 209 Can 2051 Teeth end widening end portion 901 Stator core component 901m Winding portion 901t Teeth portion (901-902) e Stator core body end portion 903 Stator core 9-1-01 Laminated structure Shape of one layer 9-1-03 Shape of one plate-like body (9-1-01) having a laminated structure and shape of another plate-like body adjacent in the axial direction (1201-1202) e of the stator core body edge

Claims (8)

A stator core component for constituting a stator core of an electric motor,
The stator core component includes a partial cylindrical part cylindrical part and a tooth part from the partial cylindrical part toward the center of the stator core,
Both end portions of the partial cylindrical portion have a joint shape corresponding to an end portion of another adjacent partial cylindrical portion, and the joint shape is a waveform curve shape along the radial direction of the stator core. A featured stator core component.   The stator core component according to claim 1, wherein the waveform curve shape is a sine wave.   The stator core component according to claim 2, wherein the sine wave has a shape corresponding to less than a half wavelength. The stator core component is formed by laminating a plurality of plate-like bodies in the central axis direction of the stator core,
At both ends of the partial cylindrical portion, a first plate-like body having a first waveform curve shape, and a second plate-like body having a second waveform curve shape obtained by inverting the first waveform curve shape, The stator core components according to claim 1, wherein the stator core components are alternately arranged along the central axis direction.   5. A plurality of the first plate-like bodies are continuously arranged along the central axis direction, and a plurality of the second plate-like bodies are continuously arranged. The stator core component described in 1.   A stator core formed by assembling the stator core component according to any one of claims 1 to 5.   An electric motor comprising the stator core according to claim 6. The electric motor includes a cylindrical can disposed inside the stator core,
8. The electric motor according to claim 7, wherein an outer peripheral diameter of the can is larger than an inner peripheral diameter formed by a tip portion of each tooth portion in a state where the stator core components are completely fitted to each other. .

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