Disclosure of utility model
The utility model provides a rotor for a permanent magnet synchronous motor, which can effectively improve the magnetizing depth of the rotor, thereby improving the performance of the rotor and the motor with the rotor.
The utility model provides a rotor for a permanent magnet synchronous motor, which comprises a rotor frame and permanent magnets, wherein the rotor frame is constructed as a hollow cylinder, the rotor frame is provided with a plurality of spacing grooves along the circumferential direction, the rotor frame is divided into a plurality of rotor frame sub-parts by the spacing grooves, the permanent magnets are arranged in the spacing grooves, wherein the rotor frame is integrally cast through a pouring gate, the rotor frame part is provided with a pouring gate stub bar corresponding to the pouring gate, the pouring gate stub bar is positioned on the end face of the rotor frame, and the pouring gate stub bar is closer to the outer circumference of the rotor frame than the inner circumference of the rotor frame.
In an embodiment according to the utility model, each rotor frame sub-portion has a gate stub bar, respectively, the number of gate stub bars being equal to the number of poles of the rotor.
In an embodiment according to the utility model, the gate stub bar has a cross section elongated in the circumferential direction, and the gate stub bar extends to the outer circumference of the rotor frame.
In an embodiment according to the utility model, the circumferential length of the cross section elongated in the circumferential direction is more than twice the radial length.
In an embodiment according to the present utility model, the cross section of the gate stub bar forms a sector ring shape, the outer circular arc of the sector ring shape having the same curvature as the outer circumference of the rotor frame, the gate stub bar being located on the outer circumference of the rotor frame.
In an embodiment according to the utility model, the gate stub bar has a circular cross section.
In an embodiment according to the utility model, the gate stub bar protrudes from an end face of the rotor frame.
In an embodiment according to the utility model, the material of the rotor frame is a plastic magnetic ferrite.
In an embodiment according to the utility model the spacer slots are adapted to accommodate magnetic field applying means during orientation and magnetizing such that the rotor frame obtains permanent magnetic properties, wherein the rotor frame sections have magnetic field directions extending in a radial direction of the rotor frame and the rotor frame sub-sections on both sides of the spacer slots have opposite magnetic field directions, respectively, wherein the magnetic field directions of the permanent magnets extend in a circumferential direction of the rotor frame, and wherein the magnetic fields of the permanent magnets in the spacer slots together with the magnetic fields of the rotor frame on both sides of the spacer slots form a continuous magnetic circuit with the shortest path.
In an embodiment according to the utility model, the spacing groove penetrates the rotor frame in the longitudinal direction of the rotor frame, the cross section of the spacing groove being configured as a trapezoid, the lower base of the trapezoid cross section being close to the inner circumference of the rotor frame.
The utility model further provides a permanent magnet synchronous motor, which comprises the rotor according to the embodiment of the utility model.
The utility model also provides a mould for casting the rotor frame of the rotor according to the embodiment of the utility model, wherein the mould is hollow, the outer contour of the mould is a hollow cylinder, the mould is provided with a plurality of spacing grooves along the circumferential direction, the mould is divided into a plurality of mould sub-parts by the spacing grooves, the mould sub-parts are provided with pouring gates, the pouring gates are positioned on the end face of the mould, and the pouring gates are closer to the outer circumference of the mould than the inner circumference of the mould, wherein the positions of the pouring gates correspond to the positions of the pouring gate stub bars of the rotor frame.
In the prior art, the magnetizer of the rotor is usually formed by stamping and stacking silicon steel sheets. However, the magnetization depth of the unoriented silicon steel sheet is not deep enough as a whole, and the magnetic conduction direction of the oriented silicon steel sheet is fixed, so that the magnetization depth is not uniform after the magnetization. Furthermore, if the silicon steel sheet is manufactured and assembled according to a desired orientation, for example, the orientation in the embodiment of the present utility model, the manufacturing and assembling process thereof is necessarily complicated and costly.
In contrast to the prior art, the rotor according to the utility model employs a rotor frame instead of a magnetizer. The rotor frame itself is magnetic and is capable of providing additional magnetic flux. The rotor is thus able to provide more magnetic flux and a synchronous machine with such a rotor can achieve more power and stronger performance. The rotor according to the present utility model is cast integrally by the gate of the mold, and the gate is closer to the outer circumference of the rotor frame than the inner circumference of the rotor frame. The closer the gate is to the outer circumference, the stronger the magnetic field the cast material is subjected to, and the more orderly the alignment of the magnetic particles in the cast material is, and the greater the density of the magnetic particles becomes, the greater the magnetic flux. In addition, the integrally formed rotor frame is formed by magnetic materials, preferably magnetic materials with low magnetic resistance and good magnetic conductivity can be selected, and the integrally formed rotor frame has simple processing technology, material saving and low cost, and is very suitable for industrial mass production.
Detailed Description
In order to make the objects, technical solutions and advantages of the technical solutions of the present utility model more clear, the technical solutions of the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings of specific embodiments of the present utility model. Like reference numerals in the drawings denote like parts. It should be noted that the described embodiments are some, but not all embodiments of the present utility model. All other embodiments, which can be made by a person skilled in the art without creative efforts, based on the described embodiments of the present utility model fall within the protection scope of the present utility model.
Possible embodiments within the scope of the utility model may have fewer components, have other components not shown in the drawings, different components, differently arranged components or differently connected components, etc. than the examples shown in the drawings. Furthermore, two or more of the elements in the figures may be implemented in a single element or a single element shown in the figures may be implemented as multiple separate elements.
Fig. 1 schematically shows an exploded view of a rotor 100 for a permanent magnet synchronous motor according to an embodiment of the present utility model. The rotor 100 includes a rotor frame 110 and permanent magnets 120. The rotor frame 110 is constructed as a hollow cylinder. In the present utility model, the rotor frame 110 is configured as a hollow cylinder, in particular, the outer contour of the rotor frame 110 being understood to be a hollow cylinder. In the embodiment according to the present utility model, the outer circumferential surface of the rotor frame 110 may be, for example, a closed surface, thereby obtaining better structural strength. A plurality of spacing grooves 130 are arranged in the circumferential direction inside the rotor frame 110, and the rotor frame 110 is partitioned into a plurality of rotor frame sub-portions 111 by the spacing grooves 130. In an embodiment according to the present utility model, the spacing groove 130 penetrates the rotor frame 110 in the axial direction. A plurality of permanent magnets 120 are respectively arranged in the spacing grooves 130, in particular, are inserted into the spacing grooves 130.
The rotor frame 110 is integrally cast. The mold for casting the rotor frame 110 has a gate, and after the cast rotor frame 110 is taken out of the mold, the rotor frame 110 forms a gate stub bar at a position corresponding to the gate. Thus, it can be seen from fig. 1. The rotor frame 110 has a gate stub bar 230 corresponding to the gate, and the gate stub bar 230 is located at an end face of the rotor frame 110. In the present utility model, the gate stub bar 230 is closer to the outer circumference of the rotor frame 130 than the inner circumference of the rotor frame 130. In other words, in casting the rotor frame 110, the gates on the mold are closer to the outer circumference of the rotor frame 110 than the inner circumference of the rotor frame 130, and preferably abut against the outer circumference of the rotor frame 110.
In the prior art, the rotor of a permanent magnet synchronous motor consists of a magnetizer and a permanent magnet. The permanent magnets may be attached to the surface of the magnetizer to constitute a surface-mounted rotor, or the permanent magnets may be inserted into the magnetizer and constitute an embedded rotor. The magnetizer of this form is stamped and stacked from silicon steel sheets, and thus cannot be manufactured by an integral molding process. In contrast to the prior art, an integrally formed rotor frame is used instead of a magnetizer in the rotor according to the utility model. In the utility model, the rotor frame can be formed by injection molding of plastic magnetic ferrite, for example, so that the rotor frame can be conveniently prepared by an integral molding process. Compared with the process of stamping and stacking silicon steel sheets, the integrated forming process of the rotor frame has the advantages of simple flow, high efficiency, high precision and low cost. In addition, the rotor frame itself composed of the plastic magnetic ferrite can provide magnetic field and magnetic force, and the magnetic permeability is far higher than that of the silicon steel sheet magnetizer.
In order to obtain stronger magnetism for the rotor frame 110 itself, the rotor frame 110 needs to be oriented during casting or injection molding such that each sub-portion of the rotor frame 110 forms an anisotropic magnet, and the rotor frame 110 needs to be magnetized such that each sub-portion of the rotor frame 110 obtains magnetism in the direction of orientation. In the orientation, the magnetic field applying means, i.e., the orientation means, is disposed on the outer circumferential surface of the rotor frame 110 and has alternating pairs of magnetic poles. The poles of the magnetic particles in the plastic magnetic ferrite in the rotor frame 110 are aligned and oriented under the external magnetic field applied by the magnetic field applying means. The orientation direction and the magnetic field trend of the rotor frame 110 will be described in more detail later. The plastic magnetic ferrite enters from the gate of the mold, the closer the gate is to the outer circumference of the rotor frame 110, the stronger the magnetic field the plastic magnetic ferrite receives, and the more orderly the alignment of the magnetic particles. The magnetic particles in the plastic magnetic ferrite are closely attached to the outer circumference of the rotor frame 110 by the magnetic field, which causes the magnetic particles to be aligned from the outside to the inside, and the density of the magnetic particles becomes larger, the larger the magnetic flux becomes. The rotor frame 110 according to the present utility model is more orderly in orientation in each sub-portion, has a larger magnetic flux, and has better rotor performance than an arrangement in which the gate is closer to the inner peripheral surface of the rotor frame 110.
In the present utility model, an integral molding process is understood to be a process in which the entire part is molded in one mold at a time. Compared with the traditional step-by-step operation manufacturing process, the integrated forming greatly reduces the cost of part production, has higher production speed, and can produce various parts, products, tools and the like in a short time. The integrated forming process is relatively simple, the required profile, holes, surface treatment and the like can be finished in one die, the production time and cost can be greatly reduced, and meanwhile, the production precision and repeatability of the parts can be improved. In the conventional processing method, preparation work of a die and a template is needed first, and then the parts are processed step by step. The integrated forming process is adopted without the requirement of additionally preparing templates and the like, so that the process is really completed in one step, and the processing efficiency and the processing speed are greatly improved. In addition, the die designed by the integral molding process is usually produced at one time, so that the speed is very high, mass production can be rapidly finished, and market demands can be more rapidly met. The integrated forming process not only can meet the requirements of the traditional manufacturing field, but also can be applied to some high and new fields, such as generators, car washing manufacturing, medical appliances and the like. In these areas, the integrated process can create more precise, higher quality parts and products.
In the embodiment of the utility model, the plastic magnetic ferrite for injection molding the rotor frame has low magnetic resistance, good magnetic permeability and deep magnetizing depth, and is suitable for integral molding and industrial production. In an embodiment according to the utility model, the plastic magnetic ferrite may be, for example, a mixture of nylon and ferrite. The rotor frame made of plastic magnetic ferrite accommodates the permanent magnets, and the rotor space is thus fully utilized, so that the rotor can provide a larger magnetic flux with a constant volume. The plastic magnetic ferrite has a smaller density than the silicon steel material, which results in a reduction in weight of a rotor made of the plastic magnetic ferrite, and thus the power density and energy efficiency of the motor can be improved. In addition, the plastic magnetic ferrite has smaller hysteresis loss than the silicon steel material and has higher resistivity, and the rotor made of the plastic magnetic ferrite may thus have lower eddy current loss than the rotor made of the silicon steel material.
In the embodiment according to the present utility model, after casting and demolding, the gate stub bar 230 must be formed on the rotor frame 110 due to the presence of the gate. The gate stub bar 230 may protrude from an end face of the rotor frame 110, for example. Alternatively, the gate stub bar 230 may also be removed, e.g., sheared off, but may still leave a mark on the end face of the rotor frame 110.
In an embodiment according to the present utility model, each rotor frame shelf portion 111 of the rotor frame 110 may have, for example, a gate stub bar 230, respectively. The number of gate stubs 230 is equal to the number of poles of the rotor. As shown in fig. 1, magnetic poles are formed in each of the rotor frame sub-portions 111, respectively, and the rotor has 5 pairs of poles (10 poles). The rotor frame has 10 gate stubs 230. Accordingly, the mold for casting the rotor frame has 10 gates. The material for casting, such as plastic-magnetic ferrite, can be filled into the cavity to a minimum by the corresponding gate path to form the corresponding rotor frame sub-portion 111. The rotor frame sub-portions 111 and their gates each correspond to one magnetic pole of the magnetic field applying device, and thus the material entering from the corresponding gate can be more strongly influenced by the corresponding magnetic pole, and thus can have a more orderly orientation and stronger magnetism.
Fig. 2 shows a cross-sectional view of a rotor frame 110 according to an embodiment of the utility model. In this embodiment, the gate stub bar 230 has, for example, a cross section elongated in the circumferential direction, and the gate stub bar 230 is abutted against the outer circumference of the rotor frame 110 or extends to the outer circumference of the rotor frame 110. As mentioned before, the closer the gate is to the outer circumference of the rotor frame 110, the stronger the magnetic field of the magnetic field applying means to which the plastic-magnetic ferrite is subjected during injection molding. In order to bring the gate closer to the outer circumference of the rotor frame 110 as a whole, the gate is designed as an elongated opening in the circumferential direction, and the gate stub 230 accordingly forms an elongated cross section. In an embodiment according to the utility model, the circumferential length of the cross section elongated in the circumferential direction may for example be more than twice the radial length, and the maximum length in the circumferential direction of the cross section elongated in the circumferential direction may for example be more than twice the maximum length in the radial direction, and preferably more than a factor. In a more preferred embodiment, the cross section of the gate elongated in the circumferential direction may form, for example, a sector ring shape, and the outer circular arc of the sector ring shape has the same curvature as the outer circumference of the rotor frame 110. The gate stub bar 230 may thus be located on the outer circumference of the rotor frame 110, i.e. partially coinciding with the contour of the outer circumference. In this case, the gate of the mold for casting the rotor frame 110 may be disposed on the outer circumference of the rotor frame 110, that is, close to the outer circumference to the greatest extent.
In an embodiment according to the present utility model, the spacing groove 130 penetrates the rotor frame 110 in the longitudinal direction of the rotor frame 110. The cross section of the spacing groove 130 may be configured as a trapezoid, for example, with a lower base of the trapezoid cross section being adjacent to an inner circumference of the rotor frame 110 and an upper base of the trapezoid cross section being adjacent to an outer circumference of the rotor frame 110. In the trapezoidal space slots 130, trapezoidal permanent magnets 120 are arranged, which allows the magnetic field to pass through the rotor frame 110 more, thereby reducing magnetic leakage.
Fig. 3 shows a schematic view of the magnetic field profile of a rotor frame 110 according to an embodiment of the utility model. During casting of the rotor frame 110, magnetic field applying means, i.e. orientation means 310, are arranged around the rotor frame 110. The orienting device 310 has alternating pairs of poles. In the embodiment of fig. 3, 5 pairs of poles (10 poles) are shown. According to the usual regulations, the magnetic field lines start from the N pole to the S pole outside the magnet and the magnetic field lines start from the S pole to the N pole inside the magnet. All embodiments of the utility model describe the magnetic field profile according to the above specifications. As can be seen from fig. 3, the poles of the orientation means 310 are arranged corresponding to the respective rotor frame portions. The magnetic field applied by the orientation device 310 extends in a radial direction in the rotor frame sub-portions on either side of one of the spacer slots 130 and has opposite directions. For example, the magnetic field direction in rotor frame subsection 311 is oriented outwardly in the radial direction of rotor frame 110 and the magnetic field direction of rotor frame subsection 312 is oriented inwardly in the radial direction of rotor frame 110. Under the action of the external magnetic field, the magnetic poles of the magnetic particles in the plastic magnetic material, such as plastic magnetic ferrite, change from an originally disordered arrangement to an orderly arrangement consistent with the trend of the external magnetic field, and the respective rotor frame portions thus appear as anisotropic ferromagnetic materials with an orientation direction consistent with the trend of the external magnetic field. In the subsequent magnetizing process, the trend of the magnetic field applied by the magnetizing device is consistent with the orientation direction. The rotor frame 110 and the respective rotor frame sections acquire permanent magnetism under the action of the magnetizing apparatus. Through the orientation process, each rotor frame section will have better magnetic permeability, i.e. higher magnetic permeability and lower magnetic reluctance, in a particular direction.
In further embodiments according to the present disclosure, during orientation and magnetizing, magnetic field applying means may be arranged in addition to the rotor frame 110, for example in the spacer grooves 130. The magnetic field applied by the magnetic field applying means in the space slots 130 may be the same as the magnetic field of the permanent magnet 120, for example. This will be described in detail later. By additionally arranging magnetic field application means in the spacer slots 130, a stronger magnetic field can be applied to the rotor frame and the ferromagnetic particles therein, so that these ferromagnetic particles can be aligned according to the desired magnetic field course and have better magnetic permeability, i.e. higher magnetic permeability and lower magnetic resistance, along the magnetic field course.
Fig. 4 shows a schematic view of the magnetic field profile of a rotor according to an embodiment of the utility model. In the embodiment shown in fig. 4, the rotor frame 110 of the rotor 100 has been oriented and magnetized and permanent magnetic properties are obtained. The permanent magnet 120 is inserted into the interval slot 130. The magnetic field direction of the permanent magnets 120 is designed such that the rotor frame sub-portions on both sides of one of the spacing grooves 130 and the permanent magnets 120 form a continuous magnetic circuit with the shortest path. In an embodiment according to the present utility model, the material of the permanent magnet 120 may include ferrite, neodymium iron boron, samarium iron nitrogen, and samarium cobalt, for example. The permanent magnet composed of samarium cobalt, neodymium iron boron or samarium iron nitrogen has strong remanence, high power density, high coercivity and good demagnetizing resistance, so that the permanent magnet is very suitable for high-power and high-torque motors. In an embodiment according to the utility model, the permanent magnet 120 may be sintered or bonded, for example, as sintered ferrite. In the case where the permanent magnets are made of sintered ferrite, the entire rotor is completely free of rare earth material, and thus the cost of the rotor is further reduced.
In the embodiment shown in fig. 4, rotor 100 has alternating N and S poles and forms a rotor with multipole pairs. It should be noted that the magnetic poles of the rotor 100 or the rotor frame 111 itself shown in fig. 4, and the magnetic poles of the external magnetic field applying device 310 are shown in fig. 3. The corresponding rotor frame sub-portions form N poles under the action of the S poles of the external magnetic field applying means 310, and the corresponding rotor frame sub-portions form S poles under the action of the N poles of the external magnetic field applying means 310. The magnetic field profiles in fig. 4 and 3 are identical. As shown in fig. 4, the S-pole-corresponding rotor frame sub-portion of the rotor 100 has a radially inwardly extending magnetic field direction, and the N-pole-corresponding rotor frame sub-portion of the rotor 100 has a radially outwardly extending magnetic field direction. Between adjacent S-and N-poles of the rotor 100, the magnetic field starts from the S-pole, transitions through the permanent magnet in the shortest path and reaches the N-pole, the magnetic field in the permanent magnet extending in the circumferential direction. For example, the permanent magnet 421 is arranged into the spacing groove 431, the permanent magnet 422 is arranged into the spacing groove 432, and the permanent magnet 423 is arranged into the spacing groove 433. The magnetic field direction of the permanent magnet 423 extends in the circumferential direction of the rotor frame 110 and is opposite to the magnetic field direction of the adjacent permanent magnet 422. On either side of permanent magnet 422 or spacing slot 432 are rotor frame sub-portions 411 and 412 and on either side of permanent magnet 423 or spacing slot 433 are rotor frame sub-portions 412 and 413. As can be seen in fig. 4, the magnetic field extends inwardly in the radial direction of the rotor frame 110 in the rotor frame sub-portion 412, starting from the corresponding S pole of the rotor frame sub-portion 412. The magnetic fields are then split, with one portion of the magnetic field bending through permanent magnet 422 and another portion of the magnetic field bending through permanent magnet 423. The magnetic field extends counterclockwise in the circumferential direction of the rotor frame 110 in the permanent magnets 422, bends after passing through the permanent magnets 422 and extends outwardly in the radial direction of the rotor frame 110 through the rotor frame sub-portion 411 to the corresponding N-pole of the rotor frame sub-portion 411. The magnetic field extends clockwise in the circumferential direction of the rotor frame 110 in the permanent magnets 423, bends after passing through the permanent magnets 423 and extends outwardly in the radial direction of the rotor frame 110 through the rotor frame sub-portion 413 to the corresponding N-pole of the rotor frame sub-portion 413. The direction and orientation of the magnetic fields in the other rotor frame sub-portions and the permanent magnets can be known comparably based on the above description of the direction and orientation of the magnetic fields in the rotor frame sub-portions 411, 412 and 413 and the permanent magnets 422 and 423.
Fig. 5 shows a cross-sectional view of a rotor frame 110 according to another embodiment of the present utility model. In the embodiment shown in fig. 5, the gate stub bar 530 has a circular cross section. Accordingly, the gate of the mold for casting the rotor frame 110 also has a circular cross section. From the viewpoint of mold processing and manufacturing, the processing difficulty of the round gate is smaller than that of the long and narrow gate. However, the round gate is separated from the outer circumference Zhou Gengyuan of the rotor frame 110 as a whole than the slit gate, so that the material for casting, such as the plastic-magnetic ferrite, is subjected to an external magnetic field having a smaller intensity than the slit gate and the alignment of the magnetic particles is less uniform than the slit gate during casting or injection molding.
The utility model further provides a permanent magnet synchronous motor, which comprises the rotor according to the embodiment of the utility model. The permanent magnet synchronous motor may also be a brushless dc motor, for example.
The utility model also provides a die. The mold is used for casting or injection molding a rotor frame of a rotor according to an embodiment of the present utility model. The mold is hollow, the outer contour of the mold is configured as a hollow cylinder, the mold is provided with a plurality of spacing grooves along the circumferential direction, the mold is divided into a plurality of mold sub-parts by the spacing grooves, wherein the mold sub-parts are provided with a pouring gate, the pouring gate is positioned on the end face of the mold, and the pouring gate is closer to the outer circumference of the mold than the inner circumference of the mold, wherein the position of the pouring gate corresponds to the position of a pouring gate stub of the rotor frame.
Herein, unless defined otherwise, technical or scientific terms used herein should be given the ordinary meaning as understood by one of ordinary skill in the art to which the present utility model pertains. The terms "first," "second," and the like in the description and in the claims, are not used for any order, quantity, or importance, but are used for distinguishing between different elements. Likewise, the terms "a" or "an" and the like do not necessarily denote a limitation of quantity. The word "comprising" or "comprises", and the like, means that elements or items preceding the word are included in the element or item listed after the word and equivalents thereof, but does not exclude other elements or items. The terms "connected" or "connected," and the like, are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "upper", "lower", "left", "right", etc. are used merely to indicate relative positional relationships, which may also be changed when the absolute position of the object to be described is changed.
While the exemplary embodiments of the proposed solution of the present utility model have been described in detail with reference to the preferred embodiments, it will be understood by those skilled in the art that various changes and modifications may be made to the specific embodiments described above without departing from the spirit of the utility model, and various technical features and structures of the proposed solution may be combined without departing from the scope of the utility model, which is defined by the appended claims.