Compressor motor and method for magnetizing rotor thereof

A compressor motor and a method for magnetizing a rotor thereof are provided. The compressor motor includes a stator and a rotor configured to electromagnetically interact with the stator to be rotated, wherein the rotor includes a core, a plurality of magnets inserted into the core, and a cover configured to cover both end portions of the core and to be injection-molded so as to fill accommodation spaces that are formed between the core and the plurality of magnets.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from Korean Patent Application Nos. 10-2016-0041806 and 10-2017-0015368 filed on Apr. 5, 2016 and Feb. 3, 2017, respectively, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

Field of the Invention

The present disclosure relates to a compressor motor, and more particularly to a compressor motor in which a plurality of magnets are inserted into a rotor.

Description of the Related Art

In general, a compressor that forms one element of a refrigerating cycle is provided with a compressor motor, and such a compressor motor is classified into several types in accordance with a driving method thereof. As an example, a capacity variable type compressor uses a brushless motor, and includes an inverter that is controlled by a controller. Such a variable type compressor generally uses a method for driving a compressor motor through applying of a voltage that is generated in accordance with a switching operation of a switching element provided in the inverter to motor windings.

Such a compressor motor is composed of a stator and a rotor, and the rotor is configured to electromagnetically interact with the stator and is rotated by a force that acts between a magnetic field and current that flows through a coil.

The rotor is briefly classified into a SPM (Surface Permanent Magnet) type in which magnets surround a rotor in accordance with the coupling structure thereof and an IPM (Interior Permanent Magnet) type in which magnets are buried and fixed into a rotor.

Since the SPM type rotor is surrounded by the magnets having uniform reluctance, there occurs no reluctance change, and thus the rotor is operated purely in dependence upon torques that are generated by the magnets. Accordingly, the torques generated per unit current become low to deteriorate efficiency of the rotor. Further, the SPM type rotor has the drawback that man-hour, such as a magnet bonding process, becomes complicated, and during high-speed rotation of the rotor, the magnet may secede from a core to form a gap between the magnet and the core. Further, eddy current may flow in a non-magnetic body to cause a power loss to occur.

Accordingly, the IPM type rotor, in which the magnets are buried and fixed into the rotor, has been proposed.

However, in an environment where the rotor is rotated at a low speed in order to heighten the efficiency of the motor, the magnets may be moved while the rotor is rotated at a constant speed, for example, at a low speed.

In the case where the magnets are moved as described above, the magnets may be deformed or damaged due to friction between the magnets and the core. Further, in the case where fine powder that is generated as the magnets are worn down is discharged together with a coolant that flows into a compression chamber of the compressor, a cylinder, a piston, and a valve device may be damaged. If the powder that is generated due to the abrasion of the magnets continuously circulates in the refrigerating cycle together with the coolant, an expansion valve may be clogged.

On the other hand, if the magnets, which are inserted into the rotor, have already been magnetized prior to the insertion, it is required to determine polarities of the magnets when the magnets are inserted into the rotor and to arrange the magnets so that the polarities of the magnets cross each other. Accordingly, it is required to confirm the polarities of the magnets one by one when inserting the magnets into the rotor, and this may cause a delay in a rotor manufacturing process.

In order to solve the delay problem in the rotor manufacturing process and to easily manufacture the rotor, non-magnetized magnets are inserted into the rotor. The magnets, which initially have no polarity, may have the polarities through a magnetization process in a state where the magnets are inserted into the rotor. Since the magnets have the polarities, the rotor may be rotated through electrical interaction with the stator on the inside of the stator. Through the rotation of the rotor, the driving force of the motor can be transferred to the compressor.

In this case, it is required to match the position of the rotor with a magnetization device so that a portion that becomes a magnetic pole of the non-magnetized magnet corresponds to the magnetic pole position of magnetic flux that is generated by the magnetization device. In the related art, in order to match the magnetization position of the rotor with the magnetization device, a guide hole is formed on an upper portion of the rotor, and a pin is inserted into the guide hole to match the rotor with the magnetization position. Further, during the magnetization, the rotor is fixed to the magnetization position by the pin.

However, in matching the magnetization position of the rotor using the guide hole and the pin and fixing the rotor to the magnetization position in the related art, the pin may not be accurately inserted into an insertion hole, and thus a cover may be broken to cause foreign substances to be generated. Further, during the magnetization, the pin may be damaged due to magnetization impacts. If the pin is damaged, the rotor is rotated by a rotating magnetic field that is formed in the magnetization process to cause the magnetization position to be distorted. Accordingly, the magnetization of the magnets may fail or may be insufficiently performed, and thus the performance of the motor that includes such a rotor may be deteriorated.

SUMMARY OF THE INVENTION

Exemplary embodiments of the present disclosure overcome the above disadvantages and other disadvantages not described above, and provide a compressor motor which can prevent movement of magnets inserted into a core while a rotor is rotated.

Further, exemplary embodiments of the present disclosure provide a compressor motor which can easily and accurately locate a rotor in a magnetization position before magnetization of magnets and can prevent rotation of the rotor during the magnetization of the magnets.

According to an aspect of the present disclosure, a compressor motor includes a stator; and a rotor, wherein the rotor includes a core; a plurality of magnets inserted into the core; and a cover configured to cover both end portions of the core and to be injection-molded so as to fill accommodation spaces that are formed between the core and the plurality of magnets.

The accommodation spaces may be provided between upper or lower end portions of the magnets and a plurality of insertion holes of the core into which the plurality of magnets are respectively inserted.

The cover may include extension portions that occupy the accommodation spaces.

The extension portions may have cross sections that are in a triangle shape.

The accommodation spaces may be formed along edges of at least one of the upper and lower end portions of the magnets.

The accommodation spaces may be provided between inclined surfaces that are formed along edges of at least one of upper and lower end portions of the magnets and inner peripheries of a plurality of insertion holes of the core into which the respective magnets are respectively inserted.

The inclined surfaces may be formed on at least parts of the edges of the upper or lower end portions of the magnets.

The inclined surfaces may be formed to be downwardly inclined in outside directions of the magnets.

The magnets may be “C”-type magnets (e.g. magnets in “C” shape in which one surface thereof convexly projects toward the center of the core).

The cover may include rotation prevention guides configured to prevent the rotor from being rotated while the plurality of magnets are magnetized.

The rotation prevention guides may be formed to project from parts of the cover that covers one end portion of the core.

The rotation prevention guides may be symmetrically arranged about a center of the core.

According to another aspect of the present disclosure, a compressor motor includes a stator; and a rotor, wherein the rotor includes a plurality of magnets having inclined surfaces that are formed along edges of upper and lower end portions of the magnets; a core configured to have a plurality of insertion holes which are formed thereon and into which the plurality of magnets are respectively inserted; first and second covers configured to cover both end portions of the core by means of injection molding; and extension portions integrally formed with the first and second covers, wherein the extension portions occupy accommodation spaces that are formed between inner peripheries of the plurality of insertion holes and the inclined surfaces of the plurality of magnets.

The inclined surfaces may be formed to be downwardly inclined in outside directions of the magnets.

The magnets may be “C”-type magnets (e.g. magnets in “C” shape in which one surface thereof convexly projects toward the center of the core).

The second cover may include rotation prevention guides that are integrally injection-molded with the second cover.

The rotation prevention guides may fix the rotor thereto when the magnets are magnetized.

The rotation prevention guides may locate the rotor in a magnetization position.

The rotation prevention guides may be symmetrically formed about a center of the core.

According to still another aspect of the present disclosure, a method for magnetizing a plurality of magnets that are inserted into an inside of a rotor of a compressor motor includes setting a magnetization position of the rotor through straight movement of a fixing jig; moving a magnetization yoke so that a plurality of projections of the magnetization yoke are inserted into positions that correspond to the plurality of magnets of the rotor; and magnetizing the plurality of magnets through application of a magnetization power to the magnetization yoke.

The setting the magnetization position of the rotor may rotate the rotor to the magnetization position through pushing of the fixing jig to rotation prevention guides that project from one end portion of the rotor in an axis direction of the rotor.

The fixing jig may continuously support the rotation prevention guides during the magnetization.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

Hereinafter, exemplary embodiments of the present disclosure will be described in detail with reference to accompanying drawings. The following description of the exemplary embodiments is based on the most suitable embodiments in understanding the technical features of the present disclosure. However, the technical features of the present disclosure are not limited by the embodiments to be described, but it is exemplified that the present disclosure may be implemented by the embodiments to be described hereinafter.

Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the present disclosure. In addition, in order to help understanding of the embodiments to be described hereinafter, like drawing reference numerals are used for the like elements, even in different drawings.

Hereinafter, the configuration of a compressor motor according to a preferred embodiment of the present disclosure will be described in detail with reference to the accompanying drawings.

FIG. 1is a perspective view illustrating a rotor that is applied to a compression motor according to an embodiment of the present disclosure, andFIG. 2is a perspective view illustrating a state where a cover ofFIG. 1is removed.

Referring toFIGS. 1 and 2, a compressor motor according to an embodiment of the present disclosure includes a stator (not illustrated) and a rotor1. In this case, the rotor1may be inserted into the stator, and may be electromagnetically interact with the stator to be rotated. In this embodiment, it is exemplified that the rotor1is configured to be arranged in the stator, but is not limited thereto. The stator may also be arranged to be fixed to an inside of the rotor, and in this case, the rotor may also be configured to be rotated in a state where it surrounds the stator.

In the center of the rotor1, a rotating shaft1ais inserted along an axis direction (Z-axis direction). In this case, both ends of the rotating shaft1aare rotatably supported inside the compressor motor.

The rotor1as described above includes a core100that is made of a metal that is a magnetic material, a plurality of magnets300inserted into the core100, and an injection-molded cover200configured to cover both end portions of the core100.

The core100may be formed by laminating a plurality of thin plate sheets each of which has a predetermined thickness. In the center of the inside of the core100, a fixing hole110, into which the rotating shaft1ais fixedly inserted, may be formed, and a coupling groove (not illustrated) for coupling iron core sheets may be formed.

Further, around the fixing hole110of the core100, a plurality of inflow holes133and indication holes135may be penetratingly formed along a circumferential direction (P direction inFIG. 3A), and a plurality of insertion holes150for inserting the plurality of magnets300therein may be formed.

During injection molding of the cover200, resin may flow into the inflow holes133. The resin that flows into the inflow holes133serves to connect an upper cover210that covers an upper end portion of the core100and a lower cover230that covers a lower end portion of the core100, which will be described later, to each other.

Since the injection-molded cover200covers the both end portions of the core100, the plurality of magnets300are not exposed to an outside. In this case, the indication holes135enable a user to recognize an arrangement of the plurality of magnets300. The plurality of insertion holes150are formed to correspond to the shape of the magnets300, and are arranged at equal intervals along the circumferential direction around the fixing hole110.

Further, the plurality of insertion holes150are formed closest to an outside of the rotor1, and this is to arrange the plurality of magnets300adjacent to the stator. In this case, the core100forms magnetic paths that are generated from the plurality of magnets300.

The plurality of magnets300are inserted into the plurality of insertion holes150, respectively, to be radially arranged around the rotating shaft1a. In this embodiment, it is exemplified that 6 magnets300are arranged. However, the number of magnets being arranged is not limited thereto, but may be variously set.

Each of the plurality of magnets300may be in a “C” shape in which one surface thereof convexly projects toward the center of the core100. In the case where the magnet300is in the “C” shape as described above, the cross-sectional area of the magnet300becomes larger than the cross-sectional area of a bar-shaped magnet to cause a torque of the magnet to be increased. Further, a magnetic resistance torque can be increased through concentration of the magnetization direction.

FIG. 3Ais a plan view of a rotor of a compressor motor according to an embodiment of the present disclosure, andFIG. 3Bis an enlarged view of a portion III indicated inFIG. 3A.FIG. 4is a cross-sectional view taken along line IV-IV indicated inFIG. 1, andFIG. 5is an enlarged view of a portion V indicated inFIG. 4.

The cover200may include the upper cover210and the lower cover230that cover upper and lower end portions of the core100. As described above, since the upper cover210is molded after resin is inserted into the plurality of inflow holes133, it can be integrally connected to the lower cover230. In this case, when the resin that forms the cover200is injection-molded, the accommodation spaces160(seeFIG. 3B) are formed between inner peripheries of the plurality of insertion holes150and the plurality of magnets300. The accommodation spaces160may be formed between inclined surfaces320,330,340, and350that are processed at both ends of the respective magnets300and the inner peripheries of the respective insertion holes150so as to facilitate the assembly thereof when the magnets300are inserted into the insertion holes150, respectively. On the upper cover210and the lower cover230, extension portions250(seeFIG. 5) that fill the accommodation spaces160are formed.

The plurality of magnets300are arranged in a mold for forming the cover200in a state where they are inserted into the insertion holes150of the core100, respectively. Then, through a following injection process, the cover200is integrally formed with the core100and the plurality of magnets300.

The upper and lower covers210and230are respectively coupled to upper and lower end portions of the core100. The upper and lower covers210and230prevent the plurality of magnets300from seceding from the respective insertion holes150of the rotor1in an axis direction. Further, the upper and lower covers210and230may be injection-molded to properly change their shapes to keep the balance in the case where imbalance exists on the rotor1.

The extension portions250that are formed on the respective covers210and230are shaped to roughly correspond to the accommodation spaces160so as to fill the accommodation spaces160. Since the accommodation spaces160are filled with the extension portions250as described above, the respective magnets300are prevented from moving in a radius direction of the rotor1in the respective insertion holes150even in the case where the rotor1is rotated not only at high speed but also at low speed. Accordingly, the rotor1is prevented from vibrating due to the movement of the magnets during the rotation thereof, and thus structural intensity and stability can be improved.

Referring toFIG. 3A, the plurality of “C”-shaped magnets300that are inserted into the insertion holes150of the core100are arranged in a symmetrical structure inside the core, and both ends thereof project toward an outside of the core100.

Referring again toFIG. 2, each of the magnets300may include a first side surface360that is arranged toward the rotating shaft1a(seeFIG. 9A) and a second side surface370that is directed opposite to the first side surface360, and may further include a third side surface380and a fourth side surface390for connecting the first side surface360and the second side surface370. The lengths of upper ends of the first and second side surfaces360and370of the magnet300are set to be longer than those of the third and fourth side surfaces380and390.

Each of the magnets300may have the inclined surfaces320,330,340, and350that are formed to be downwardly inclined in an outside direction of the magnet300along edges that are connection portions between the respective side surfaces360,270,380, and390and an upper end surface310. The inclined surfaces may include the first inclined surface320that is formed along an upper end of the first side surface360, the second inclined surface330that is formed along an upper end of the second side surface370, the third inclined surface340that is formed along an upper end of the third side surface380, and the fourth inclined surface350that is formed along an upper end of the fourth side surface390.

Referring toFIG. 3B, if the magnet300that has the first to fourth inclined surfaces320,330,340, and350is inserted into the insertion hole150, the accommodation spaces160may be formed between the inner periphery of the insertion hole150and the first to fourth inclined surfaces320,330,340, and250.

Referring toFIG. 4, the extension portions250that are formed on the upper and lower covers210and230as described above are shaped to correspond to the accommodation spaces160as the resin is pushed into the accommodation spaces160in the process of injection-molding the cover200.

As described above, since the extension portions250are formed between the inner peripheries of the respective insertion holes150and the respective inclined surfaces320,330,340, and350of the magnets300, they can thoroughly prevent the respective magnets300from moving in the radius direction of the rotor1in the respective insertion holes150by centrifugal forces when the rotor1is rotated (e.g., is rotated at low speed). Accordingly, the magnets300are stably fixed into the respectively insertion holes150, and thus the structural intensity and the stability of the rotor1can be improved. Further, the magnets300can be prevented from being worn down while the magnets300rub against the core100due to their movement in the insertion holes150as the rotor1is rotated.

In this embodiment, since it is not necessary to cut parts of the core100(e.g., upper edges of the insertion hole150) in order to provide the accommodation spaces160for forming the extension portions250, magnetic paths can be maintained as they are, and thus leakage magnetic flux can be reduced. Further, since it is not necessary to add a separate configuration for preventing the movement of the magnets300, the radius of the rotor1can be prevented from being unnecessarily increased to achieve miniaturization of the compressor motor.

On the other hand, the respective inclined surfaces of the magnet300can be formed along not only the upper edge of the magnet300but also the lower edge of the magnet300.

Referring toFIG. 5, distances A1and A2between the inclined surfaces320and330of the magnet300and the inner periphery151of the insertion hole150may be larger than 0.1 times the thickness T of the magnet300, and may be smaller than 0.5 times the thickness T thereof. That is, the distances A1and A2between the inclined surfaces320and330and the inner periphery151may be in the range between 0.1 times and 0.5 times the thickness T. In addition, it is sufficient that the inclined surfaces320and330are formed so that the inclined surfaces320and330and the inner periphery151of the insertion hole150are spaced apart from each other to the extent that the accommodation space160can be formed between the magnet300and the inner periphery151of the insertion hole150. For example, the inclined surfaces may be formed maximally from a point315that corresponds to a half of the thickness T/2 of the magnet300, and may be formed minimally from a point that corresponds to 1/10 of the thickness T/10 of the magnet300.

The distance A1between the first inclined surface320and the inner periphery151of the insertion hole150may be set to be different from the distance A2between the second inclined surface330and the inner periphery151of the insertion hole150. Accordingly, the cross-sectional areas of the formed accommodation spaces160may be set to be different from each other.

The angle θ1that is made between the inclined surface320of the magnet and an extension line of the upper end surface310of the magnet300may be larger than 0° and may be smaller than 90°. The angle θ1that is made between the first inclined surface320and the extension line of the upper end surface310may be set to be different from the angle θ2that is made between the second inclined surface330and the extension line of the upper end surface310.

In accordance with a difference between the distances between the inclined surface and the inner periphery151of the insertion hole150and a difference between the angles made between the inclined surface and the extension line of the upper end surface310, the cross-sectional areas of the accommodation spaces160that are formed between the inclined surface of the magnet300and the inner periphery151of the insertion hole150may be set to be different from each other.

A predetermined gap G may be formed between the inner periphery151of the insertion hole150and the magnet300so that the magnet300can be smoothly inserted into the core100. Since the gap G is formed to be quite narrow in the range of 0.05 mm to 0.2 mm, it does not cause anxiety that resin flows into the gap G during the injection molding of the cover200.

On the other hand, due to the inclined surfaces320,330,340, and350, the cross section of the extension portion250may be roughly in a triangle shape (e.g., in a wedge shape). As described above, the cross-sectional shape of the extension portion250is affected by the shapes of the inclined surfaces320,330,340, and350. That is, if the inclined surfaces320,330,340, and350are curved surfaces or multi-bent surfaces, one surface of the extension portion250that corresponds to the inclined surfaces follows the shapes of the inclined surfaces.

FIGS. 6A, 6B, and 6Care plan views illustrating various examples of magnets buried in a rotor of a compressor motor according to an embodiment of the present disclosure.

As illustrated inFIGS. 6A to 6C, the number of accommodation spaces160to be formed may be changed in accordance with the inclined surfaces that are formed on the magnets301,302, and303.

Referring toFIG. 6A, on the magnet301, the inclined surfaces320and330may be formed only at edges that connect the upper end surface310, the first side surface360, and the second side surface370. In this case, the accommodation spaces160are formed only between the first and second inclined surfaces320and330and the inner periphery151of the insertion hole150. Accordingly, the number of extension portions250to be formed is set to correspond to the accommodation spaces160.

Referring toFIG. 6B, only the third and fourth inclined surfaces340and350may be formed on the magnet302. Further, referring toFIG. 6C, only the first and third inclined surfaces320and340may be formed on the magnet303.

As described above, since the positions of the inclined surfaces of the magnet300are variously set, it is possible to form the extension portions250of various shapes that can prevent the movement of the magnet300during the injection molding of the cover200.

FIG. 7is a plan view illustrating a state where a magnetization device is coupled to a rotor according to an embodiment of the present disclosure.

In order to solve the problem that a process for manufacturing the rotor1is delayed and to easily manufacture the rotor1, non-magnetized magnets300are inserted into the rotor1. The magnets300, which initially have no polarity, may have the polarities through a magnetization process in a state where the magnets300are inserted into the rotor1. In this case, it is required to match the position of the rotor with a magnetization device so that a portion that becomes a magnetic pole of the non-magnetized magnet corresponds to the magnetic pole position of magnetic flux that is generated by the magnetization device.

FIG. 7is a plan view illustrating a state where a magnetization device is coupled to a rotor according to an embodiment of the present disclosure.

The magnets300are magnetized through application of a magnetization power to a separate magnetization yoke11.

The magnetization device10is configured to include the magnetization yoke11and a body portion15(seeFIG. 10). The magnetization yoke11forms a ring-shaped outer periphery, and includes a plurality of projections13that project from the magnetization yoke11to an inside. The projections13are arranged to be spaced apart from each other for a predetermined distance to face outer surfaces of the plurality of magnets300. The plurality of projections13form the polarities of the magnets300through magnetization of the respective magnets300that correspond to the respective projections13.

If a high magnetization power is instantaneously applied to the magnetization yoke11, magnetic domains of the magnet300that is within the range of magnetic fields that are formed around the respective projections13are arranged in a constant direction to cause the magnet300to have the polarity.

If the magnets300are magnetized in a state where the magnets300and the projections13are positioned to depart from each other, the amount of magnetization becomes insufficient to deteriorate the driving efficiency of a motor (not illustrated). Accordingly, it is required to match the position of the rotor1with the magnetization yoke11so that the respective non-magnetized magnets300correspond to the magnetic fields that are generated from the respective projections13of the magnetization yoke11. In order to match the magnetization position of the rotor1with the magnetization yoke11, the rotor1may be provided with a pair of rotation prevention guides270.

The pair of rotation prevention guides270may project from an outer surface of the lower cover230that covers one end portion103of the core100. The pair of rotation prevention guides270may be arranged to correspond to the positions of a pair of magnets300that face each other among the plurality of magnets300. Since the injection-molded cover200covers both end portions101and103of the core100, the plurality of magnets300are not exposed to an outside, and thus it is not possible to grasp the positions of the magnets by the naked eye. However, the positions of the magnets300that are inserted into the rotor1can be indirectly known through the positions of the rotation prevention guides270.

If the magnetization position of the rotor1is set through rotation of the rotor1so that a pair of rotation prevention guides270correspond to a pair of projections13that face each other among the plurality of projections13, the positions of the plurality of magnets300can be arranged to coincide with the positions of the plurality of projections13of the magnetization yoke11.

In this case, a fixing jig20(seeFIG. 9A) to be described later may be used to rotate the rotor1to the magnetization position. The fixing jig20will be described in detail with reference toFIG. 9A.

A plurality of rotation prevention guides270may be formed. Specifically, a first rotation prevention guide270aand a second rotation prevention guide270bmay be formed. In this case, the rotation prevention guides270aand270bmay be symmetrically arranged about the center of the core100. The centers of the first and second rotation prevention guides270aand270band the core100are arranged in a straight line.

The first rotation prevention guide270amay be formed in a position in which the first magnet300is inserted, and the second rotation prevention guide270bmay be formed in a position in which the second magnet300is inserted. The first and second magnets300aand300bare symmetrically arranged about the center of the core100.

A straight line Hy as illustrated inFIG. 7is a line that connects the core center and the centers of the first and second projections13aand13bthat are symmetrically arranged about the core center with each other, and corresponds to a reference line Hy that indicates the magnetization position of the rotor. In the case where a center line Hr, which connects the center of the first rotation prevention guide270aand the center of the second rotation prevention guide270bwith each other, coincides with the reference line Hy, the position of the rotor1is called the magnetization position. When the rotor1is in the magnetization position, the plurality of magnets300are positioned to correspond to the plurality of projections13. Accordingly, the magnets300can be sufficiently magnetized in the magnetization position of the rotor1.

Even if the rotor1is rotated only at a predetermined angle from the magnetization position, the magnetization angle of the magnets300gets twisted. In this case, a center line Hx and the reference line Hy do not coincide with each other. If the magnetization is made in a state where the rotor1is rotated even at the predetermined angle from the magnetization position, non-magnetized portions may occur on the magnets300. For sufficient magnetization of the magnets300, the rotation prevention guides270match the magnetization position of the rotor1through the fixing jig20, and fix the rotor1into the magnetization position of the rotor1during the magnetization.

On the other hand, if excessively strong rotating magnetic field is formed on the rotor due to high magnetization power that is applied to the magnetization yoke11during the magnetization of the magnets300, the rotor1may be moved while it is rotated or shaken due to the rotating magnetic field. If the rotor1is rotated during the magnetization, the magnets300may not be magnetized properly. To prevent this, it is required to fixedly support the rotor1so that the rotor1is prevented from being moved during the magnetization of the magnets300.

The rotor is fixed to the magnetization position without being rotated by the fixing jig20to be described later.

FIG. 8is a view illustrating rotation prevention guides formed on a lower cover.

Referring toFIG. 8, the rotor1includes the rotation prevention guides270that project from the surface of the cover200that covers one end portion of the core100. In this case, without being limited to the lower cover, the rotation prevention guides270locate the rotor1in the magnetization position before the magnetization of the magnet300, and fixedly support the rotor1in the magnetization position during the magnetization of the magnets300.

The rotation prevention guides270may be integrally injection-molded with the cover200. Since the rotation prevention guides270are integrally injected with the cover200, the number of components that are required to manufacture the rotor is reduced. Accordingly, the manufacturing cost of the rotor1is reduced, and the manufacturing process of the rotor1is simplified.

The rotation prevention guides270are formed to project from parts of the lower cover230. The rotation prevention guides270may be formed to extend from the lower cover230to an outside of the core100. The rotation prevention guides270are formed to have a predetermined height so as to be fixedly supported by the fixing jig20to be described later. The rotation prevention guides270may be formed to project from the lower cover230with a height that is substantially equal to or larger than 1 mm and equal to or smaller than 20 mm.

The rotation prevention guides270include the first rotation prevention guide270aand the second rotation prevention guide270bthat are symmetrically arranged about the center of the core100. The first and second rotation prevention guides270aand270binclude support surfaces273aand273bthat come in contact with the fixing jig20to be described later. A first fixing portion22(seeFIG. 9A) of the fixing jig20comes in surface contact with the first support surface273aof the first rotation prevention guide270a, and a second fixing portion24(seeFIG. 9A) of the fixing jig20comes in surface contact with the second support surface273bof the second rotation prevention guide270b. The rotation prevention guides270and the fixing jig20rotate the rotor1into the magnetization position before the magnetization, and fixedly support the rotor1so that the rotor1is not rotated during the magnetization.

The first and second rotation prevention guides270bmay be formed in a semicircular shape, but are not limited thereto. The first and second rotation prevention guides270aand270bmay be radially formed as long as the first and second rotation prevention guides270aand270bcan be symmetrically formed. Hereinafter, referring toFIGS. 9A and 9B, a process of matching the rotor1with the magnetization position in order to magnetize the magnets300that are inserted into the rotor1will be described.

FIG. 9Ais a plan view illustrating a state before rotation prevention guides of a rotor are supported by a fixing jig according to an embodiment of the present disclosure, and shows a state before the rotor is set in the magnetization position.FIG. 9Bis a plan view illustrating a state where rotation prevention guides of a rotor are supported by a fixing jig according to an embodiment of the present disclosure, and shows a state where the rotor is set into the magnetization position.

Referring toFIG. 9A, before the magnetization of the magnets300, it is required to set the magnetization position of the rotor1so that the positions of the magnets300correspond to the positions of the projections13of the magnetization yoke11. A separate fixing jig20may be provided to match the rotor1with the magnetization position.

The fixing jig20has a first fixing portion22and a second fixing portion24, which extend toward the rotor1, and a length portion21that extends toward an opposite direction of the rotor1.

The first fixing portion22and the second fixing portion24may be branched from one end of the length portion21, and may be symmetrically formed about the length portion21. The first fixing portion22may support the first rotation prevention guide270aof the rotor1, and the second fixing portion24may support the second rotation prevention guide270bof the rotor1. The first fixing portion22includes a first fixing surface23athat comes in surface contact with the first support surface273aof the first rotation prevention guide270a, and the second fixing portion24includes a second fixing surface23bthat comes in surface contact with the second support surface273bof the second rotation prevention guide270b.

The length portion21is connected to a driving portion (not illustrated) to make the fixing jig20reciprocate in a straight line in an X-axis direction. Here, the driving portion may use a hydraulic or pneumatic cylinder device.

Hereinafter, referring toFIGS. 9A and 9B, a process of setting the magnetization position of the rotor1through the fixing jig20will be described.

It is assumed that the rotor1before setting of the magnetization position is in a position in which the center line Hx is rotated clockwise as much as a predetermined angle θ from the reference line Hy as shown inFIG. 9A. In this case, the second rotation prevention guide270bis arranged to be closer to the fixing jig20than the first rotation prevention guide270a.

In this case, if the fixing jig20straightly moves toward the rotor1along the X-axis direction, the second fixing surface23bof the fixing jig20and the second support surface273bof the second rotation prevention guide270bfirst come in contact with each other. In this state, if the fixing jig20continues to move straight in the X-axis direction, the second rotation prevention guide270bis pushed by the second fixing portion24, and the rotor1is rotated counterclockwise.

If the rotor1is rotated counterclockwise as much as the predetermined angle θ, the first support surface273aof the first rotation prevention guide270aand the first fixing surface23aof the first fixing portion22come in contact with each other to make the center line Hx of the rotor coincide with the reference line Hy. Accordingly, as shown inFIG. 9B, the rotor1can be set into the magnetization position.

As described above, since the fixing jig20supports the rotation prevention guides270in order to magnetize the plurality of magnets300that are inserted into the rotor1, the rotor1can be accurately located in the magnetization position. Through the method for setting the magnetization position of the rotor according to the present disclosure, a part of the cover or the core can be prevented from being damaged by impacts, and the magnetization position of the rotor can be set accurately and easily.

Further, while the magnets300are magnetized, the fixing jig20continuously support the rotation prevention guides270to prevent the rotor1from being rotated. Accordingly, it becomes possible to prevent the magnetization position of the rotor1from getting twisted during the magnetization process.

FIG. 10is a side cross-sectional view illustrating a state before a magnetization device is coupled to a rotor according to an embodiment of the present disclosure.

The fixing jig20fixedly supports the rotor1to prevent the rotor1from being moved as being rotated or shaken in the magnetization yoke11by the influence of the rotating magnetic field. Accordingly, during the magnetization of the magnets300, the polarity arrangement of the magnets300can be formed accurately and uniformly.

The magnetization device10includes the magnetization yoke11and the yoke body15that surrounds the magnetization yoke11. The yoke body15is formed in a cylindrical shape that extends in the length direction of the magnetization yoke11from an upper portion of the magnetization yoke11that is arranged in the yoke body15. The yoke body15may ascend or descend up and down (Z-axis direction). A through-hole17is formed on a lower portion of the yoke body15so that the rotor1passes through the through-hole17.

If the magnetization device10descends in the direction of the rotor1, magnetization of the magnets300that are inserted into the rotor1is performed. Hereinafter, a process of magnetizing the magnets300will be described.

The rotor1is provided to be rotated in the stator (not illustrated) through electrical interaction with the stator. The rotor1is assembled to be provided with the rotating shaft1athat is pressingly inserted into the center of the rotor1to be rotated together with the rotor1.

The rotating shaft1ais formed so that upper and lower ends thereof extend up and down for a predetermined length. The rotating shaft1athat extends to the lower portion of the rotor1is rotatably supported through a journal bearing30.

In order to match the magnetization position of the rotor1that is supported by the journal bearing30, the fixing jig20comes in contact with the rotation prevention guides270of the rotor1. Since the fixing jig20and the rotation prevention guides270come in contact with each other, it becomes possible to match the magnetization position of the rotor1accurately. Further, only through the straight movement of the fixing jig20, it becomes possible to easily match the magnetization position of the rotor1.

After the rotor1is located in the magnetization position, the magnetization device10that is located on the upper portion of the rotor1is moved downward. Through the descending of the magnetization device10, the rotor1is arranged inside the magnetization yoke11. The magnetization yoke11is in a state where it surrounds the rotor1, and the upper end of the rotor1comes in contact with the upper end of the yoke body15.

In this state, if the yoke body15is pressed downward, the rotor1is fixedly supported by the fixing jig20so that the rotor1is prevented from being moved between the journal bearing30and the magnetization yoke11. In this state, if a magnetization power is applied to the magnetization yoke11to magnetize the magnets300, the rotor1is prevented from being moved due to the rotating magnetic field that is generated in the process of magnetizing the magnets300. Accordingly, the magnets300are magnetized with uniform magnetic polarity arrangement. The magnets300that are magnetized as described above have magnetism that is higher than that of the magnetization method in the related art.

As described above, the compressor motor according to this embodiment can be applied to various home appliances, for example, a washing machine, a clothes drier, an air conditioner, a refrigerator, and a compressor.

Although the preferred embodiments of the present disclosure have been individually described, the present disclosure is not limited to the specific embodiments as described above, but it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the present invention, as defined by the appended claims. Such modified embodiments should not be individually understood from the technical concept or prospect of the present disclosure.