CN113659747B

CN113659747B - Rotor core, manufacturing method of rotor core and motor rotor

Info

Publication number: CN113659747B
Application number: CN202111207625.1A
Authority: CN
Inventors: 孙志平; 王世龙; 魏晗杰; 孔令伟
Original assignee: Jiangsu Leili Aidesi Motor Co ltd
Current assignee: Jiangsu Leili Aidesi Motor Co ltd
Priority date: 2021-10-18
Filing date: 2021-10-18
Publication date: 2022-02-25
Anticipated expiration: 2041-10-18
Also published as: CN113659747A; CN115995895A

Abstract

The present disclosure relates to a rotor core, a method of manufacturing the rotor core, and a motor rotor. The rotor core includes a plurality of laminations, each lamination having a base formed with a central axial bore and a plurality of triangular teeth circumferentially arranged around the base, wherein each triangular tooth includes an outer edge distal from the base and a tip proximate to the base. The punching sheets are stacked together, so that the central shaft holes of the punching sheets are axially aligned. The punching sheets comprise at least two end punching sheets located at the end part of the rotor core and a plurality of middle punching sheets located between the end punching sheets. The structure of the middle punching sheet is different from that of the end punching sheet.

Description

Rotor core, manufacturing method of rotor core and motor rotor

Technical Field

The disclosure relates to the technical field of motors, in particular to a rotor core, a manufacturing method of the rotor core and a motor rotor comprising the rotor core.

Background

The permanent magnet brushless direct current motor is more and more widely applied due to the advantages of high efficiency, energy conservation and the like. The air conditioner replaces the traditional alternating current induction motor to be used in the field of air conditioners, and is the necessity of the development of the energy-saving trend in recent years.

The permanent magnet brushless direct current motor mainly comprises a stator assembly, a rotor assembly, an end cover and other parts, wherein the rotor assembly is arranged in the stator assembly, and the motor is assembled after the rotor assembly is connected with the end cover in a compression mode. The stator assembly is formed by welding straight iron core windings into a circle and then performing injection molding on the circle and a BMC plastic package material through an injection mold. The rotor assembly is mainly formed by injection molding of a rotor core, a rotor shaft, a plurality of permanent magnets and PBT injection molding materials, and the rotor core is formed by laminating a plurality of rotor punching sheets through a high-punching mold.

At present, how to provide a product which can meet the requirements of the strength of a rotor core, has the minimum magnetic leakage and has the highest efficiency is a technical problem to be solved urgently in the field.

Disclosure of Invention

In view of the above-mentioned problems and needs, the present disclosure provides a rotor core that solves the above-mentioned problems and brings other technical effects by adopting the following technical features.

In one aspect, the present disclosure is directed to a rotor core including a plurality of laminations, each lamination having a base formed with a central axial bore and a plurality of triangular teeth circumferentially arranged around the base, wherein each triangular tooth includes an outer edge distal from the base and a tip proximal to the base. The punching sheets are stacked together, so that the central shaft holes of the punching sheets are axially aligned. The punching sheets comprise at least two end punching sheets located at the end part of the rotor core and a plurality of middle punching sheets located between the end punching sheets. The structure of the middle punching sheet is different from that of the end punching sheet.

According to a preferable scheme, the outer edges of all the triangular teeth of the end punching sheet are connected with each other through the outer magnetic bridges.

According to the preferable scheme, the tip of at least one pair of triangular teeth opposite to each other in all the triangular teeth of the end punching sheet is connected with the base through the inner magnetic bridge.

According to a preferred solution, among all the triangular teeth of the end punch, only one pair of triangular teeth opposite to each other is connected with the base through the inner magnetic bridge.

According to the preferred scheme, the base part and all the triangular teeth of the end punching sheet are of an integral structure.

According to a preferable scheme, the triangular teeth of the middle punching sheet are not connected with each other at the outer edge.

According to the preferable scheme, only part of the triangular teeth of the middle punching sheet are connected with the base through the inner magnetic bridge.

According to a preferred embodiment, only one pair of triangular teeth, which are opposite to each other, of all the triangular teeth of the intermediate stamped piece is connected with the base through the inner magnetic bridge.

According to the preferred scheme, two adjacent middle punching sheets are staggered by an angle relative to the longitudinal axis of the rotor core.

According to a preferred embodiment, the angle is

And is and

satisfies the following conditions:

wherein n is the number of the triangular teeth of each punching sheet, and m is an integer which is more than or equal to 1 and less than n.

According to the preferred scheme, the middle punching sheet is of a split structure and comprises a diagonal tooth punching sheet and a plurality of independent triangular teeth separated from the diagonal tooth punching sheet, and the diagonal tooth punching sheet comprises a base and two triangular teeth which are connected with the base through an inner magnetic bridge and are opposite to each other.

According to the preferred scheme, permanent magnet mounting grooves are formed between adjacent triangular teeth of each punching sheet, and the corresponding permanent magnet mounting grooves of all punching sheets are respectively aligned in the axial direction to form a plurality of permanent magnet positioning channels for containing permanent magnets.

According to a preferred solution, each triangular tooth is provided with only one through hole.

The present disclosure also provides a method for manufacturing a rotor core, including: manufacturing an end punching sheet; manufacturing a middle punching sheet, wherein the middle punching sheet is different from the end punching sheet; the end punching sheets and the middle punching sheets are arranged together in a stacking mode, the end punching sheets are located at two ends, the middle punching sheets are located in the middle, and the central shaft hole of each punching sheet is axially aligned.

According to a preferred scheme, the stacking arrangement of the two end punching sheets and the plurality of middle punching sheets comprises: so that two adjacent intermediate punching sheets are staggered by an angle relative to the longitudinal axis of the rotor core.

According to preferred scheme, make tip towards piece and make middle towards piece all include: obtaining a plate for manufacturing a punching sheet; stamping a central shaft hole on the plate; and stamping a plurality of permanent magnet mounting grooves on the plate, wherein the permanent magnet mounting grooves are circumferentially arranged around the central shaft hole to form a base part between the permanent magnet mounting grooves and the central shaft hole and a plurality of inner magnetic bridges which are connected with the base part and are positioned between the adjacent permanent magnet mounting grooves.

According to preferred scheme, make tip towards piece and make middle towards piece all include: permanent magnet locating holes are punched at two sides of each permanent magnet mounting groove.

According to preferred scheme, wherein, make tip towards piece and make middle towards piece all include: punching a plurality of through holes in the sheet material positioned around a central axial hole.

According to a preferred scheme, the manufacturing of the end punching sheet further comprises the step of stamping a plurality of permanent magnet mounting grooves on the plate, then stamping a ring groove on the plate for blanking, wherein the ring groove surrounds the permanent magnet mounting grooves and is not connected with the permanent magnet mounting grooves so as to form a plurality of triangular teeth connected through an outer magnetic bridge between the permanent magnet mounting grooves.

According to a preferred scheme, wherein the manufacturing of the intermediate stamped sheet further comprises, after the plurality of permanent magnet mounting grooves are punched on the plate: punching a protrusion at the end part of each permanent magnet installation groove far away from the central through hole, punching a ring groove on the plate for blanking, wherein the ring groove surrounds a plurality of permanent magnet installation grooves and is connected with the permanent magnet installation grooves through the protrusion to form a plurality of triangular teeth between the permanent magnet installation grooves, and the plurality of triangular teeth are not connected with each other at the outer edge due to the existence of the protrusion.

The present disclosure also proposes an electric machine rotor comprising a rotor core as described in the preamble.

Through the rotor core, the motor rotor with the rotor core and the manufacturing method of the rotor core, the technical problems mentioned in the background technology can be solved, namely, the rotor core or the motor rotor product which can meet the requirements of the strength of the core, has the minimum magnetic leakage and has the highest efficiency is obtained. The best modes for carrying out the present disclosure will be described in more detail below with reference to the accompanying drawings so that the features and advantages of the present disclosure can be readily understood.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings of the embodiments of the present disclosure will be briefly described below. The drawings are intended to depict only some embodiments of the disclosure, and not all embodiments of the disclosure are limited thereto.

Fig. 1 is an overall view of a rotor assembly employing a rotor core proposed by the present disclosure;

FIG. 2 is a cross-sectional view of one embodiment of a rotor core as set forth in the present disclosure;

fig. 3 is a lamination stack that may be used with the rotor core proposed by the present disclosure;

fig. 4 is another view of a lamination stack that may be used with the rotor core proposed by the present disclosure;

fig. 5 is a preferred structure of an end punching of a rotor core proposed by the present disclosure;

fig. 6 is a preferred structure of the middle lamination of the rotor core proposed by the present disclosure;

FIGS. 7A-7C are schematic diagrams showing the arrangement of diagonal tooth punches of the middle punch;

fig. 8 is a schematic diagram showing a manufacturing process of the end punches and the intermediate punch.

List of reference numerals

10 base

11 center axle hole

20 triangular teeth

201 independent triangular tooth

202 non-independent triangular tooth

21 outer edge

22 tip

23 through hole

3 inner bulge

4 outer protrusion

30 end punching sheet

40 middle punching sheet

5 external magnetic bridge

6 inner magnetic bridge

7 diagonal tooth punching sheet

71 first diagonal tooth punching sheet

72 second diagonal tooth punching sheet

73 third diagonal tooth punching sheet

8 permanent magnet mounting groove

81 permanent magnet positioning hole

82 projection

9 annular groove

12 permanent magnet

13 rotor shaft

14 injection molded body

141 injection molding strip

142 dodging hole

143 thimble hole

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present disclosure more clear, the embodiments of the present disclosure will be described in detail and fully with reference to the accompanying drawings. Like reference symbols in the various drawings indicate like elements. It should be noted that the described embodiments are only some of the embodiments of the present disclosure, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the described embodiments of the disclosure without any inventive step, are within the scope of protection of the disclosure.

Possible embodiments within the scope of the disclosure may have fewer components, have other components not shown in the figures, different components, differently arranged components or differently connected components, etc. than the embodiments shown in the figures. Further, two or more of the components in the drawings may be implemented in a single component, or a single component shown in the drawings may be implemented as a plurality of separate components.

Unless defined otherwise, technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this disclosure belongs. The use of "first," "second," and similar terms in the description and claims of the present disclosure are not intended to indicate any order, quantity, or importance, but rather are used to distinguish one element from another. Also, the use of 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 the element or item listed before the word covers the element or item listed after the word and its equivalents, but does not exclude other elements or items. The terms "connected" or "coupled" and the like are not restricted to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "upper", "lower", "left", "right", and the like are used merely to indicate relative positional relationships, and when the absolute position of the object being described is changed, the relative positional relationships may also be changed accordingly.

The present disclosure provides a motor rotor, which increases the structural strength and stability of a rotor core by adding an outer magnetic bridge connection structure to a rotor punching sheet and by using a reasonable distribution of lamination layers having the outer magnetic bridge punching sheet. The two utilizes the rotor punching that has interior magnetic bridge to fold the structural design who presses through rotatory, reaches further reduction rotor magnetic leakage, improves the controllability of rotor punching, the structural strength of the rotor that also increases simultaneously. The motor rotor further provided by the disclosure can comprise the rotor core according to any embodiment of the disclosure.

Referring to fig. 1-2, wherein fig. 1 is a general view of a rotor assembly employing a rotor core proposed by the present disclosure, and fig. 2 is a sectional view of one embodiment of the rotor core proposed by the present disclosure. The rotor assembly may include: injection molding 14, rotor iron core, permanent magnet 12 and rotor shaft 13. The permanent magnets 12 are embedded in the permanent magnet mounting slots 8 of the rotor core. The injection molding body 14 is used for coating and molding the rotor core and the permanent magnet 12 together, and the rotor shaft 13 is positioned in the central shaft hole 11 of the rotor core. The rotor core includes a plurality of laminations, each lamination having a base 10 formed with a central axial bore and a plurality of triangular teeth 20 circumferentially arranged around the base. Wherein each triangular tooth 20 includes an outer edge 21 distal from the base 10 and a tip 22 proximal to the base 10. The punching sheet is, for example, a silicon steel sheet.

Referring to fig. 3, a plurality of laminations are arranged in a stack such that the central axial bores 11 of the individual laminations are axially aligned. The central shaft hole 11 is available for insertion of a rotor shaft 13.

Referring to fig. 4, the plurality of laminations of the rotor core include at least two end laminations 30 located at the ends of the rotor core, and a plurality of intermediate laminations 40 located between the end laminations. For example, only two end punches 30 at both ends may be provided. Also for example, there may be two or more end punches 30 at one or both ends. In a preferred version, there is only one end punch 30 at each end.

According to the present disclosure, the structure of the middle punch 40 is different from that of the end punch 30. Therefore, different parts can have the punching sheets with different structural functions, and the performance of the rotor core is improved. For example, the end punching sheet can be provided with more magnetic bridge connection structures, so that the overall strength of the rotor is improved, and the highest strength is achieved. And the middle punching sheet can be provided with a plurality of magnetic bridge breaking parts so as to reduce the magnetic leakage of the rotor and improve the performance of the rotor. As described in more detail below.

Fig. 5 and 6 show specific structures of the end punching sheet 30 and the middle punching sheet 40, respectively. The structure of the end and middle punches of the present disclosure is not limited thereto.

In the case of the end segment 30, the outer edges of all the triangular teeth 20 of the end segment are preferably connected to one another by the outer magnetic bridges 5.

The outer magnetic bridges of the end punching sheets are connected and stacked at two ends of the middle punching sheet group, so that the structural strength of the middle punching sheet without the outer magnetic bridges is ensured, and the connection quantity of the inner magnetic bridges and the outer magnetic bridges of the whole iron core punching sheet is reduced to the minimum.

According to a preferred embodiment, the tips of at least one pair of triangular teeth opposite to each other among all the triangular teeth of the end plate are connected to the base 10 by means of the inner magnetic bridge 6.

Particularly preferably, of all the triangular teeth of the end punch, only one pair of triangular teeth opposite to each other is connected to the base by the inner magnetic bridge 6. Other triangular teeth are in a structure that the inner magnetic bridge is disconnected. The disconnection of the inner magnetic bridges is also beneficial to the blanking of products, the magnetic property loss is reduced to the maximum extent, the material is saved, and the cost is lower than that of the end punching sheet connected with all the existing inner magnetic bridges.

According to a preferred solution, the base 10 and all the triangular teeth 20 of the end punch are of a unitary structure.

The outer magnetic bridges 5 of the end punching sheets 30 are connected, so that the middle punching sheets can be reinforced, particularly the middle punching sheets which are not connected with the outer magnetic bridges are reinforced, and the angles of all the punching sheets are accurate. The end punching sheets are stacked at two ends of the middle punching sheet group, so that the triangular tooth punching sheets in the middle punching sheet group can be prevented from being peeled off and flying out, and the strength of the rotor is improved. The end punching sheet has at least two opposite triangular teeth connected with the base part 10 through the inner magnetic bridge 6, so that the structure stability of the end punching sheet is increased, the magnetic leakage of the rotor is reduced, and the performance of the rotor is improved.

For the intermediate stamped sheet 40, according to a preferred embodiment, the triangular teeth of the intermediate stamped sheet 40 are not connected to each other at the outer edge. The magnetic leakage of the rotor is reduced, the performance of the rotor is improved, and meanwhile, the structure is simple in process and attractive in appearance.

According to a preferred embodiment, of all the triangular teeth of the intermediate stamped sheet 40, only some of the triangular teeth are connected to the base 10 by means of internal magnetic bridges.

According to a preferred solution, of all the triangular teeth of the intermediate punch 40, only one pair of triangular teeth opposite to each other is connected to the base 10 by the inner magnetic bridge 6.

Referring to fig. 6, there is shown an embodiment in which the triangular teeth of the intermediate punching sheet are not connected to each other at the outer edge, and only one pair of the triangular teeth opposite to each other is connected to the base through the inner magnetic bridge. Specifically, the shown middle stamped sheet is of a split structure and comprises a diagonal tooth stamped sheet 7 and a plurality of independent triangular teeth 201 separated from the diagonal tooth stamped sheet, wherein the diagonal tooth stamped sheet comprises a base 10 and two triangular teeth which are connected with the base through an inner magnetic bridge and are opposite to each other, and the triangular teeth are referred to as non-independent triangular teeth 202 so as to be different from the independent triangular teeth 201 which are not connected with the base.

According to a preferred embodiment of the disclosure, the intermediate laminations are arranged in the stacking process in such a way that the intermediate laminations are not positioned layer by layer at the same circumferential angle, but are offset relative to each other by a certain angle about the central axis of the rotor core.

According to an advantageous embodiment, two adjacent intermediate laminations are offset relative to the longitudinal axis of the rotor coreThe angle is opened, and the angle can be the angle corresponding to one triangular tooth or a plurality of triangular teeth. In summary, the staggered angle of two adjacent middle punching sheets

Can satisfy the following conditions:

wherein n is the number of the triangular teeth of each punching sheet, and m is an integer which is more than or equal to 1 and less than n. For example, when m is 1, the intermediate punching sheet of the next layer is relatively rotated by an angle corresponding to one triangular tooth with respect to the intermediate punching sheet of the previous layer, taking a 10-tooth punching sheet as an example, and the angle is 36 °. When m is 2, the middle punching sheet of the next layer is relatively rotated by an angle corresponding to two triangular teeth relative to the middle punching sheet of the previous layer, taking a 10-tooth punching sheet as an example, and the angle is 72 degrees. Of course, the above formula is merely illustrative in general terms, and not all angles are preferred. For example, for the intermediate laminations shown in fig. 6, it should also be defined that the rotational offset angle α is not equal to 180 °, since for this configuration, a rotational offset of 180 ° does not have a substantial offset effect.

For embodiments in which the intermediate stamped pieces include the diagonal tooth stamped piece 7 and a plurality of independent triangular teeth 201, the relative positional relationship of the intermediate stamped pieces is shown in fig. 7A to 7C: fig. 7A shows a first diagonal tooth lamination 71. In fig. 7B, the second diagonal tooth punching sheet 72 is shown to be stacked in alignment with the central axial hole of the first diagonal tooth punching sheet 71, and at the same time, the second diagonal tooth punching sheet 72 is rotationally offset by an angle corresponding to one triangular tooth with respect to the first diagonal tooth punching sheet 71 around the central axial hole. In fig. 7C, a third diagonal tooth lamination 73 is shown, which is offset by the same angle further rotationally around the central axis on the basis of the second diagonal tooth lamination. Therefore, more diagonal tooth punching sheets can be pushed. In the embodiment shown in fig. 7A to 7C, adjacent punching sheets are relatively rotated by an angle corresponding to one tooth. In other embodiments, two teeth may be rotated in the same direction, or even multiple teeth may be rotated in the same circumferential direction.

If the end punching sheet is considered, the end punching sheet is firstly placed on the first layer, and the end punching sheet takes the structure of fig. 5 as an example and is provided with a pair of inner magnetic bridges which are connected diagonally. Subsequently, a first layer of the middle sheet is placed, preferably the inner bridges of the middle sheet are not aligned with the inner bridges of the end sheets, but may be offset relative thereto by an angle of one or several teeth. And then placing a second layer of middle punching sheet, so that the second layer of middle punching sheet is staggered by one or more teeth angles relative to the first layer of middle punching sheet as a whole, and so on until the complete middle punching sheet is installed. When the last end punching sheet is installed, the inner magnetic bridge of the last end punching sheet and the inner magnetic bridge of the adjacent middle punching sheet are preferably staggered.

The rotor core has firm and reliable structure, regular arrangement of the diagonal tooth punching sheets and better dynamic balance. Meanwhile, two diagonal inner magnetic bridges exist in each layer of stamped sheet, and the rest inner magnetic bridges are disconnected and not connected, so that the magnetic loss of the motor rotor can be reduced, and the performance of the rotor is improved.

To facilitate understanding of the rotationally staggered arrangement described above, a 10-tooth motor is illustrated (of course the concepts of the present disclosure are not limited to 10 teeth): the end punch, again exemplified in the structure of fig. 5, is placed in the first layer, where it has a pair of diagonally connected inner magnetic bridges, (the position of which can be considered as the initial position, and is considered as 0 °). And then, a first layer of the middle punching sheet is placed, and the inner magnetic bridges of the middle punching sheet of the first layer are rotated and staggered by 36 degrees (rotated and staggered by an angle corresponding to one tooth) or 72 degrees (rotated and staggered by an angle corresponding to two teeth) relative to the inner magnetic bridges of the end punching sheet along the circumferential direction. And then placing a second layer of middle stamped sheets, and enabling the diagonal tooth stamped sheets of the second layer of middle stamped sheets to rotate and stagger by 36 degrees or 72 degrees along the same circumferential direction relative to the diagonal tooth stamped sheets of the first layer of middle stamped sheets, and so on until the complete middle stamped sheets are installed. The last end lamination is preferably installed in such a way that the inner magnetic bridge of the last end lamination is also staggered by 36 degrees or 72 degrees with the inner magnetic bridge of the adjacent middle lamination.

According to the rotor punching sheet, the optimal arrangement of the end punching sheet and the middle punching sheet is adopted, the contact area of the punching sheets which are not connected with each other by the outer magnetic bridges 5 of the end punching sheet 30 is increased, the overall strength of the rotor is improved, and the effects of highest strength and most attractive appearance are achieved. The outer magnetic bridge of the middle punching sheet 40 is disconnected, the magnetic leakage of the rotor is reduced, and the performance of the rotor is improved. The inner magnetic bridge breaking structure of the middle punching sheet can solve the optimal scheme that the magnetic leakage of the rotor is minimum and can also ensure that the dynamic balance performance of the rotor punching sheet is optimal, and meanwhile, through the arrangement process of rotating and staggering, at least one tooth is rotated along the same direction of the circumference, and the problem of punching sheet strength caused by the fact that the inner magnetic bridge is broken through the conventional rotor punching sheet is solved.

In a conventional production process, there is generally a difference in material thickness at different locations on a base material (which may be, for example, a silicon steel sheet) due to material characteristics. Therefore, the phenomenon of uneven thickness is also reflected on the punching sheet. Because the traditional punching sheets are accumulated and laminated at the same angle position, the difference of uneven thickness is increased, and the dynamic balance performance of the rotor is seriously influenced. This problem has been solved through the arrangement mode that the rotation is staggered, because the diagonal angle tooth towards the piece of middle punching has rotated one or several teeth along the same direction of circumference for the diagonal angle towards the piece position of last layer, through this kind of rotatory staggered mode, with the uneven position equipartition of thickness in the piece of punching at different angular position to the uneven problem of whole thickness that brings because of single piece of punching thickness inequality has been solved, and then dynamic balance problem.

The technical effects are outstanding in the combined action of the characteristic effects, the problems of reducing magnetic flux leakage, improving dynamic balance, improving performance and maintaining strength are solved, the scheme can be produced in batch, and the scheme is an excellent rotor core production scheme.

According to a preferred solution, each triangular tooth is provided with only one through hole 23. Like this, between the permanent magnet contained angle, there is only through-hole 23 that a plurality of iron core punching sheet formed after piling up, and this through-hole 23 circumference equipartition is arranged, has the scheme of a plurality of through-holes for every triangle tooth, and this preferred scheme reducible processing a plurality of through-holes leads to the deformation of punching sheet, has improved rotor core's dynamic balance performance. Meanwhile, the single through hole effectively reduces the eddy current loss of the rotor core, the rotor performance is improved, the number of the through holes is small, the loss of an injection molding body can be reduced, and the product cost is reduced.

According to the present disclosure, a permanent magnet mounting groove 8 surrounding the central shaft hole is provided between adjacent triangular teeth of each punching sheet, and the corresponding permanent magnet mounting grooves 8 of all punching sheets are respectively aligned in the axial direction to form a plurality of permanent magnet positioning channels for accommodating permanent magnets. Referring to fig. 6, the inner side of the permanent magnet close to the central shaft hole is supported by an inner protrusion 3 on the base 10, and the outer side of the permanent magnet remote from the central shaft hole is supported by an outer protrusion 4, said outer protrusion 4 extending from the outer edge 21 of the triangular teeth. Therefore, the permanent magnet can be ensured not to shake, the product structure is ensured to be stable, the reject ratio of the product is reduced, and the method is beneficial to large-batch automatic production. Preferably, the permanent magnet positioning holes 81 protruding towards the triangular teeth can be formed in the side walls of the two sides of the permanent magnet mounting groove of the end punching sheet and the middle punching sheet, and the permanent magnet positioning holes 81 on the two sides of the permanent magnet mounting groove are symmetrical. Therefore, materials such as PBT flow in from the two sides of the permanent magnet along the positioning holes of the permanent magnet during injection molding, and the permanent magnet is prevented from inclining in the injection molding process to influence the magnetic field performance of the rotor.

Referring to fig. 1, the rotor core may further include an injection molded body 14, the injection molded body 14 covers the rotor core and the permanent magnet 12, and the injection molded body 14 fills the broken portion of the rotor core to form an injection molded strip 141. The injection molding bodies at the two ends are connected through injection molding strips 141 which are uniformly distributed in the circumferential direction, so that the overall strength of the rotor is further improved. The injection molding body is provided with corresponding avoiding holes 142 at through holes at two ends of the iron core, the avoiding holes 142 are larger than the iron core through holes 23, the ejector pins of the mold are also larger than the iron core through holes 23, the mold material is ensured not to overflow into the iron core through holes, and the effect of reducing the weight of the iron core is achieved. One end face of the permanent magnet is provided with two injection molding thimble holes 143, the thimble holes are directly propped against two ends of the end face of the permanent magnet, the depth and the size of the two thimble holes 143 are consistent, the end face of the permanent magnet is ensured to be horizontal, the permanent magnet is prevented from inclining during injection molding, the consistency of the installation dimension is ensured, and the performance of the whole rotor is improved.

A method of manufacturing a rotor core proposed by the present disclosure is described below. In general, the method comprises the following steps.

And manufacturing the end punching sheet. The end punching sheet has the structure of any one embodiment of the disclosure, and is preferably the end punching sheet shown in the attached figure 5.

And manufacturing a middle punching sheet, wherein the structure of the middle punching sheet is different from that of the end punching sheet. The middle punching sheet has the structure of any one embodiment of the disclosure, and is preferably the middle punching sheet shown in the attached figure 6.

And (5) stacking. Namely, two end punching sheets and a plurality of middle punching sheets are arranged together in a stacking mode, wherein the two end punching sheets are located at two ends, the middle punching sheets are located in the middle, and the central shaft hole of each punching sheet is axially aligned.

Preferably, whether the end punching sheet or the middle punching sheet is manufactured, the method can comprise the following steps: 1. and obtaining a plate, such as a silicon steel sheet, for manufacturing the punching sheet. 2. Stamping a central axial hole in the plate. This is exemplarily shown in process step 1 of fig. 8. 3. And stamping a plurality of permanent magnet mounting grooves on the plate, wherein the permanent magnet mounting grooves are circumferentially arranged around the central shaft hole to form a base part between the permanent magnet mounting grooves and the central shaft hole and a plurality of inner magnetic bridges which are connected with the base part and are positioned between the adjacent permanent magnet mounting grooves. This is exemplarily shown in process 2 of fig. 8. Wherein the permanent magnet mounting groove is preferably of generally rectangular configuration and has two extensions at a location adjacent the base. Due to the presence of the two projections, an inner projection 3 on the base can subsequently be formed (see fig. 6).

Preferably, no matter make the tip towards the piece, make the intermediate punching piece, after punching a plurality of permanent magnet mounting grooves, all can include: punching permanent magnet positioning holes 81 at both sides of each permanent magnet mounting groove; (this is shown in step 3 of fig. 8).

Preferably, whether end punches or intermediate punches are made, a plurality of through holes 23 are punched in the sheet material positioned around the central axial hole. This may be performed simultaneously with the step of punching the central shaft hole 11, as shown in process 1 of fig. 8.

As shown in the figure, the content of the step 4 is to press the inner magnetic bridge. That is, all of the triangular teeth are connected to the base by an inner magnetic bridge prior to step 4. After the step 4, most of the inner magnetic bridges are punched out, and only one pair of triangular teeth opposite to each other is left to be connected with the base through the inner magnetic bridges. After stamping a plurality of permanent magnet mounting slots, the steps of manufacturing the end laminations and manufacturing the middle laminations are different. This can be seen in fig. 8, after process step 4, a different process route is formed. The end punching sheets are formed by working

procedures

1, 2, 3, 4 and 5, and the middle punching sheets are formed by working

procedures

1, 2, 3, 4, 6 and 7.

For manufacturing the end punching sheet, after punching a plurality of permanent magnet installation grooves on the plate, the method further comprises the following steps: stamping annular groove 9 is in order to carry out the blanking on the panel, the annular groove surrounds a plurality of permanent magnet mounting grooves and does not link to each other with the permanent magnet mounting groove to form a plurality of triangle teeth that link to each other through outer magnetic bridge between the permanent magnet mounting groove. This is shown in step 5.

For manufacturing the intermediate punching sheet, after punching a plurality of permanent magnet installation grooves on the plate, the method further comprises the following steps: a protrusion 82 is stamped at the end of each permanent magnet mounting slot remote from the central through hole. See step 6, which is a step not included in the manufacture of the end punch. Thereafter, referring to process 7, a ring groove 9 is punched on the plate material to perform blanking, the ring groove surrounding the plurality of permanent magnet installation grooves and connected with the permanent magnet installation grooves by the protrusions 82 to form a plurality of triangular teeth between the permanent magnet installation grooves, the plurality of triangular teeth being disconnected from each other at outer edges due to the presence of the protrusions.

In the production process, the end punching sheet can be firstly generated and is blanked on the rotary mechanism. And the middle punching sheets are also blanked on the rotating mechanism, but the program controls the middle punching sheets to fall on the end punching sheets, and the punching is continuously carried out according to the production mode of the middle punching sheets to form second, third, fourth to N middle punching sheets and blanking. The second intermediate punching sheet is formed and blanked before the swing mechanism, the swing mechanism for program control blanking rotates one or more teeth on the basis of the inner magnetic bridge of the end punching sheet, blanking of the second intermediate punching sheet is performed after rotation, the swing mechanism also rotates before blanking of the third intermediate punching sheet, so that the fourth, fifth and N intermediate punching sheets are stacked, riveting and stacking of the punching sheets are performed while blanking of the end punching sheet is generated, and thus forming of the rotor core structure in the patent is completed.

Exemplary embodiments of the proposed solution of the present disclosure have been described in detail above with reference to preferred embodiments, however, it will be understood by those skilled in the art that many variations and modifications may be made to the specific embodiments described above, and that many combinations of the various technical features and structures presented in the present disclosure may be made without departing from the concept of the present disclosure, without departing from the scope of the present disclosure, which is defined by the appended claims.

Claims

1. A rotor core comprising a plurality of laminations, each lamination having a base formed with a central axial bore and a plurality of triangular teeth arranged circumferentially around the base, wherein each triangular tooth comprises an outer edge distal from the base and a tip proximal to the base, characterized in that:

the punching sheets are stacked together, so that the central shaft holes of the punching sheets are axially aligned;

the punching sheets comprise at least two end punching sheets positioned at two end parts of the rotor core and a plurality of middle punching sheets positioned between the end punching sheets;

the structure of the middle punching sheet is different from that of the end punching sheet;

the punching sheet comprises a pair of triangular teeth, a pair of triangular teeth and a central punching sheet, wherein only one pair of triangular teeth opposite to each other in all the triangular teeth of the end punching sheet are connected with a base through an inner magnetic bridge;

and the two adjacent middle punching sheets are staggered by an angle relative to the longitudinal axis of the rotor core; the angle is alpha, and alpha satisfies:

，

2. The rotor core of claim 1 wherein outer edges of all of the triangular teeth of the end laminations are connected to one another by outer magnetic bridges.

3. The rotor core of claim 1 wherein the base of the end laminations and all of the triangular teeth are of a unitary construction.

4. The rotor core of claim 1 wherein all of the triangular teeth of the intermediate laminations are unconnected to each other at the outer edges.

5. The rotor core according to claim 1, wherein there are permanent magnet mounting slots between adjacent triangular teeth of each lamination sheet, and corresponding permanent magnet mounting slots of all lamination sheets are respectively aligned in an axial direction to form a plurality of permanent magnet positioning channels for accommodating permanent magnets.

6. The rotor core according to claim 1, wherein each of the triangular teeth is provided with only one through hole.

7. A method of manufacturing a rotor core, comprising:

manufacturing an end punching sheet;

manufacturing a middle punching sheet, wherein the structure of the middle punching sheet is different from that of the end punching sheet;

wherein, make tip towards piece and middle towards piece for make: in all the triangular teeth of the end punching sheet, only one pair of triangular teeth which are opposite to each other are connected with the base through the inner magnetic bridge, in all the triangular teeth of the middle punching sheet, only one pair of triangular teeth which are opposite to each other are connected with the base through the inner magnetic bridge, the middle punching sheet is of a split structure and comprises a diagonal tooth punching sheet and a plurality of independent triangular teeth which are separated from the diagonal tooth punching sheet, and the diagonal tooth punching sheet comprises the base and two triangular teeth which are connected with the base through the inner magnetic bridge and are opposite to each other;

the end punching sheets and the middle punching sheets are arranged together in a stacking mode, wherein the end punching sheets are located at two ends, the middle punching sheets are located in the middle, and the central shaft holes of the punching sheets are axially aligned;

arranging two of the end laminations and a plurality of the intermediate laminations in a stacked manner comprises: make two adjacent middle punching sheets stagger an angle relative to rotor core's longitudinal axis each other, just the angle is alpha, and alpha satisfies:

8. The method of manufacturing a rotor core according to claim 7, wherein manufacturing the end laminations and manufacturing the middle laminations each comprise:

obtaining a plate for manufacturing a punching sheet;

stamping a central shaft hole on the plate;

and stamping a plurality of permanent magnet mounting grooves on the plate, wherein the permanent magnet mounting grooves are circumferentially arranged around the central shaft hole to form a base part between the permanent magnet mounting grooves and the central shaft hole and a plurality of inner magnetic bridges which are connected with the base part and are positioned between the adjacent permanent magnet mounting grooves.

9. The method of manufacturing a rotor core according to claim 7, wherein manufacturing the end laminations and manufacturing the middle laminations each comprise:

permanent magnet locating holes are punched at two sides of each permanent magnet mounting groove.

10. The method of manufacturing a rotor core according to claim 8, wherein manufacturing the end laminations and manufacturing the middle laminations each comprise:

punching a plurality of through holes in the sheet material positioned around a central axial hole.

11. The method of manufacturing a rotor core according to claim 8, wherein manufacturing the end segment punch further comprises:

after stamping a plurality of permanent magnet mounting slots in the sheet material:

stamping the annular grooves on the plate for blanking, wherein the annular grooves surround the permanent magnet mounting grooves and are not connected with the permanent magnet mounting grooves so as to form a plurality of triangular teeth connected through an outer magnetic bridge between the permanent magnet mounting grooves.

12. The method of manufacturing a rotor core according to claim 8, wherein manufacturing the intermediate lamination further comprises:

stamping a protrusion at an end of each permanent magnet mounting slot distal from the central through hole;

stamping annular groove is in order to carry out the blanking on the panel, the annular groove surrounds a plurality of permanent magnet mounting grooves and passes through protruding and permanent magnet mounting groove links to each other to form a plurality of triangle teeth between the permanent magnet mounting groove, a plurality of triangle teeth are because the existence of protruding and not continuous each other in the outer fringe.

13. An electric machine rotor, characterized in that it comprises a rotor core according to any one of claims 1-6.