Rotor core, rotor assembly, motor and electronic pump

Abstract

The invention provides a rotor core, a rotor assembly comprising the rotor core, a motor comprising the rotor assembly and an electronic pump comprising the motor. The rotor core is formed by overlapping a first number of first silicon steel sheets and a second number of second silicon steel sheets along the axial direction; each first silicon steel sheet comprises a main body part and a peripheral part, a plurality of through grooves spaced from one another are formed in the peripheral part in the circumferential direction, and each second silicon steel sheet has the same shape as the main body part of the first silicon steel sheet, so that the first silicon steel sheet and the second silicon steel sheet are overlapped in the overlapped state. The second groove wall of the through groove of the first silicon steel sheet is flush with the peripheral wall section of the second silicon steel sheet. By adopting the structural design of the rotor core or the rotor assembly, the cost is greatly reduced, the performance loss of the magnet is reduced, and the reliability of the product is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of motors, and in particular to a rotor core, a rotor assembly comprising the rotor core, a motor comprising the rotor assembly, and an electronic pump comprising the motor. Background Art

[0002] In brushless motors, rotors with surface-mounted magnets are often used. These surface-mounted magnets can be retained by a retaining frame on the outer circumference of a rotor core, for example, which is made of stacked silicon steel sheets. The rotor core, magnets, and retaining frame are then injection-molded together and fixed.

[0003] As in the technical solutions known in the prior art, a plastic retainer is usually provided to retain the magnet in the radial direction between the plastic retainer and the outer peripheral surface of the rotor core. However, in this technical solution, the mold cost of the retainer is relatively high and it is not easy to assemble. Moreover, since the magnet needs to be inserted between the silicon steel sheet and the plastic retainer, a certain gap is often required between the plastic retainer and the silicon steel sheet. A large gap may cause the magnet to loosen after assembly, resulting in the problem of the magnet position slipping or even falling off during transportation to the injection molding machine. In addition, due to the existence of the gap, the magnetic gap between the magnet and the silicon steel sheet becomes larger, resulting in increased magnetic resistance and reduced magnetic properties. If the gap is designed to be too small, it will cause the magnet to be difficult to insert or unable to be inserted, and the magnet surface will be severely scratched. For this reason, it is necessary to propose an improved fixing structure for rotor magnets. Summary of the invention

[0004] The object of the present invention is to solve at least one of the above problems and / or other problems existing in the prior art.

[0005] To achieve the above-mentioned purpose, according to a first aspect of the present invention, a rotor core is provided, which is formed by stacking a first number of first silicon steel sheets and a second number of second silicon steel sheets together in an axial direction; wherein each first silicon steel sheet includes a main body portion and a peripheral portion, and a plurality of through grooves spaced apart from each other are arranged in the circumferential direction in the peripheral portion, and each through groove includes a first groove wall and an opposite second groove wall; each second silicon steel sheet has a shape consistent with the main body portion of the first silicon steel sheet, so that when the first silicon steel sheet and the second silicon steel sheet are in a stacked state, the second groove wall of each through groove is flush with the corresponding peripheral wall segment of the second silicon steel sheet.

[0006] According to an embodiment of the present invention, a protrusion protruding toward the second groove wall is provided on the first groove wall of each through groove. Preferably, the number of the protrusions may be one or more.

[0007] According to an embodiment of the present invention, the rotor core includes only one first silicon steel sheet, and the only first silicon steel sheet is interposed between the second silicon steel sheets.

[0008] According to one embodiment of the present invention, the rotor core includes a plurality of first silicon steel sheets, wherein in the stacked state, the plurality of first silicon steel sheets are arranged relative to each other so that their respective through grooves are aligned one by one in the axial direction, and the plurality of first silicon steel sheets are inserted between the second silicon steel sheets at intervals relative to each other in the axial direction.

[0009] According to one embodiment of the present invention, the outer contour of the first silicon steel sheet is circular, and the outer contour of the second silicon steel sheet is a regular polygon, each side of the regular polygon corresponds to a peripheral wall segment of the second silicon steel sheet; corresponding to each peripheral wall segment of the second silicon steel sheet, the first silicon steel sheet is provided with a through groove for a rotor magnet to pass through.

[0010] According to an embodiment of the present invention, the second number of the second silicon steel sheets is greater than the first number of the first silicon steel sheets.

[0011] According to a second aspect of the present invention, a rotor assembly is provided. The rotor assembly comprises a plurality of rotor magnets and the rotor core as described above, wherein each rotor magnet passes through a corresponding through slot of the first silicon steel sheet.

[0012] According to an embodiment of the present invention, the rotor core and the rotor magnet are formed into an integral part by plastic overmolding.

[0013] According to a third aspect of the present invention, there is provided an electric motor, comprising the rotor assembly as described above.

[0014] According to a fourth aspect of the present invention, an electronic pump is provided, comprising the motor as described above.

[0015] By using the rotor core or rotor assembly according to the present invention, at least one of the following beneficial technical effects can be achieved: the expensive plastic retaining frame and the expensive injection mold are eliminated, thereby greatly reducing the cost; by keeping the rotor magnet tightly against the rotor core, the magnetic resistance between the rotor magnet and the rotor core (such as silicon steel sheet) is reduced, thereby reducing the magnet performance loss and torque loss; at the same time, the relative position between the rotor magnet and the rotor core can be stably maintained, making it difficult for the rotor magnet to slip or deviate. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The features and advantages of the present invention will be clearly understood through the detailed description provided below with reference to the accompanying drawings. It should be understood that the following drawings are only schematic and not necessarily drawn to scale, and thus cannot be regarded as limiting the present invention, wherein:

[0017] Figure 1 It is an exploded perspective view of a rotor assembly according to the prior art;

[0018] Figure 2 is an exploded perspective view of a rotor assembly according to the present invention;

[0019] Figure 3a is a top view of a single first silicon steel sheet constituting a rotor core according to an embodiment of the present invention;

[0020] Figure 3b yes Figure 3a A partial enlarged view of detail A;

[0021] Figure 4 is a top view of a single second silicon steel sheet constituting a rotor core according to an embodiment of the present invention; and

[0022] Figure 5a-Figure 5b A perspective view and a side view of a rotor core according to an embodiment of the present invention are respectively shown. DETAILED DESCRIPTION

[0023] Embodiments of the present invention are described below with reference to the accompanying drawings. In the following description, many specific details are set forth so that those skilled in the art can more fully understand and implement the present invention. However, it will be apparent to those skilled in the art that the present invention may be implemented without some of these specific details. In addition, it should be understood that the present invention is not limited to the specific embodiments described. On the contrary, any combination of the features and elements described below may be considered to implement the present invention, regardless of whether they relate to different embodiments. Therefore, the following aspects, features, embodiments and advantages are intended for illustration only and should not be considered as elements or limitations of the claims unless explicitly stated in the claims.

[0024] In the following, terms such as "first", "second", etc. are used to describe the elements of the present application. These terms are only used to distinguish the various elements, and are not used to limit the nature, order or number of these elements. The terms "including" and "having" are used to express an open-ended inclusive meaning, and mean that there may be additional elements / components in addition to the listed elements / components.

[0025] As mentioned in the background art, in existing motor designs, surface mounted magnets are usually held on the outer periphery of the rotor core by a plastic retainer. Figure 1, which shows an exploded perspective view of a rotor assembly known in the prior art, the rotor assembly 100' comprises a rotor core 110' formed by stacking a plurality of silicon steel sheets, a plurality of rotor magnets 120', a plastic retainer 130' for retaining the rotor magnets 120' on the periphery of the rotor core 110', and an injection molded shell 140'. Figure 1 In the rotor assembly 100' shown, a plurality of radial grooves 131' are provided on the radial inner side of the plastic retainer 130', and the radial grooves 131' are intended to be aligned with the outer peripheral wall section of the rotor core 110' formed by stacked silicon steel sheets to define a space for accommodating the rotor magnet 120'. However, in order to facilitate the assembly of the rotor magnet, the space is designed so that the rotor magnet is arranged therein in a clearance fit manner, which may cause the rotor magnet to be loose after assembly, and due to the presence of the clearance, the magnetic resistance increases and the magnetic performance decreases.

[0026] To this end, the present invention proposes an improved solution, which enables the rotor magnets to be held or fixed in a manner that is simpler to assemble, has better performance, and is more cost-effective.

[0027] Specifically, Figure 2 As shown, the present invention proposes an improved rotor assembly 100, which includes a plurality of rotor magnets 120 and a rotor core 110, wherein the rotor core 110 is formed by stacking a first number of first silicon steel sheets 111 and a second number of second silicon steel sheets 112 together in an axial direction. Advantageously, the second number of the second silicon steel sheets 112 is greater than, preferably significantly greater than, the first number of the first silicon steel sheets 111, so that in the rotor core 110, the second silicon steel sheets 112 serve as main silicon steel sheets, and the first silicon steel sheets 111 serve as auxiliary silicon steel sheets.

[0028] Figure 3a 1 shows a top view of a single first silicon steel sheet 111 constituting a rotor core 110 according to an embodiment of the present invention, Figure 3b Shows Figure 3a A partial enlarged view of detail A in Figure 4 A top view of a single second silicon steel sheet 112 constituting the rotor core 110 according to an embodiment of the present invention is shown.

[0029] Depend on Figure 3aIt can be seen that each first silicon steel sheet 111 includes a main body portion 111a and a peripheral portion 111b. For example, the outer contour of the first silicon steel sheet 111 is circular, the main body portion 111a is a portion located in the center of the first silicon steel sheet 111 (for example, a regular polygon), and the peripheral portion 111b is a circumferential portion connected to the main body portion 111a. A plurality of through grooves 1111 spaced apart from each other are arranged in the peripheral portion 111b of each first silicon steel sheet 111 along the circumferential direction, and each through groove 1111 includes a first groove wall 1111a and an opposite second groove wall 1111b.

[0030] As a preferred embodiment, a protrusion 1112 protruding toward the second slot wall 1111b is provided on the first slot wall 1111a of each through slot 1111. Preferably, the number of the protrusions 1112 may be one or more. When the rotor magnet 1200 is inserted through the through slot 1111, the protrusion 1112 can be used to hold the rotor magnet 120 against the rotor core 110 with a pre-tightening force.

[0031] Each second silicon steel sheet 112 has a shape consistent with the main body portion 111a of the first silicon steel sheet 111. Figure 4 In a specific example of the second silicon steel sheet 112 shown in FIG. 1 , it can be seen that the outer contour of the second silicon steel sheet 112 is a regular polygon, and each side of the regular polygon corresponds to an outer peripheral wall segment 1121 of the second silicon steel sheet 112, so that when the first silicon steel sheet 111 and the second silicon steel sheet 112 are stacked, the second groove wall 1111b of each through groove 1111 is flush with the corresponding outer peripheral wall segment 1121 of the second silicon steel sheet 112 (as shown in FIG. 1 ). Figure 5a Corresponding to each outer wall section 1121 of the second silicon steel sheet 112, the first silicon steel sheet 111 is provided with a through slot 1111 for a rotor magnet 120 to pass through, and the size of the through slot 1111 is slightly larger than the size of the rotor magnet 120. In addition, a central through hole is opened in the center of the first silicon steel sheet 111 and the second silicon steel sheet 112 for the rotor shaft (not shown in the figure) to pass through.

[0032] The number of the first silicon steel sheets 111 as auxiliary silicon steel sheets may be one or more. In an embodiment including only one first silicon steel sheet, the only first silicon steel sheet may be inserted between a plurality of second silicon steel sheets 112, for example, centrally inserted between a plurality of second silicon steel sheets 112; in an embodiment including a plurality of (for example, two, three or four, or other number) first silicon steel sheets 111, in the overlapping state of the first silicon steel sheet and the second silicon steel sheet, the plurality of first silicon steel sheets 111 may be arranged relative to each other so that the respective through grooves 1111 are aligned one by one in the axial direction, and the plurality of first silicon steel sheets 111 are inserted between the second silicon steel sheets 112 spaced apart from each other in the axial direction. Such a spacing arrangement of the first silicon steel sheets is advantageous because it reduces the rigidity of the protrusion 1112 on the first slot wall 1111a intended to be interference-fitted with the rotor magnet, thereby avoiding scratching of the outer peripheral surface coating of the rotor magnet 120.

[0033] See especially Figure 5a-5b The stacked rotor core 110 shown includes three first silicon steel sheets 111, which are stacked so that their respective through slots 1111 are aligned one by one in the axial direction, so that multiple rows of through slots are formed along the circumferential direction, wherein each row of through slots includes three through slots. Figure 5a-5b In the example shown, the three first silicon steel sheets 111 are inserted between the plurality of second silicon steel sheets 112 at equal intervals from each other. The first silicon steel sheets may also be arranged between the second silicon steel sheets at unequal intervals from each other, depending on actual design requirements.

[0034] It should be known that since the rotor magnet can be closely attached to the silicon steel sheet of the rotor core in the radial direction by means of the protrusion on the first slot wall of the through slot, the magnetic resistance between the rotor magnet and the rotor core is reduced, thereby reducing the magnet performance loss and reducing the torque loss.

[0035] After the rotor core and the plurality of rotor magnets are assembled to each other, the formed assembly is injection-molded to finally form a one-piece rotor assembly.

[0036] The present invention also relates to a motor including the above-mentioned improved rotor core or rotor assembly, which has reduced cost and simple assembly, and because there is reduced magnetic resistance between the rotor magnet and the rotor core (such as silicon steel sheet), the magnetic properties of the motor are greatly improved. The motor according to the present invention can be applied to multiple technical fields, for example, it can be applied to an electronic water pump to provide driving force for the electronic water pump as a power part. However, it should be understood that the motor according to the present invention is not limited to a water pump motor, but can also be other types of brushless motors and permanent magnet synchronous motors, such as power steering system motors, shift motors, clutch motors, brake motors, gasoline pumps, oil pumps and other fields.

[0037] According to the improved solution of the present invention, two silicon steel sheets of different configurations are designed and combined, and one of the silicon steel sheets is made into a circular outer contour, for example, and a through groove is provided in the circumferential direction for accommodating magnets, so that the expensive retaining frame in the prior art is omitted, which greatly saves parts and simplifies the assembly process, reducing the overall cost. In addition, by providing a protrusion on a slot wall to hold the rotor magnet against the rotor core, it can be ensured that the rotor magnet is tightly attached to the outer peripheral wall surface of the silicon steel sheet, avoiding the problem of large magnetic resistance and large magnetic performance loss caused by the gap, and at the same time, it can stably maintain the relative position between the two, so that the rotor magnet is not easy to slip and deviate.

[0038] For those skilled in the art, various modifications and variations may be made to the embodiments disclosed above without departing from the scope or spirit of the present invention. Other embodiments of the present invention will be apparent to those skilled in the art from the practice of the present invention disclosed in this specification. This specification and the examples disclosed therein should be considered to be illustrative only, and the true scope of the present invention is specified by the appended claims and their equivalents.

Claims

1. A rotor core, characterized in that: The rotor core (110) is formed by stacking a first number of first silicon steel sheets (111) and a second number of second silicon steel sheets (112) together in an axial direction; wherein each first silicon steel sheet comprises a main body portion (111a) and a peripheral portion (111b), and a plurality of through slots (1111) spaced from each other are arranged in the peripheral portion in a circumferential direction, and each through slot comprises a first slot wall (1111a) and an opposite second slot wall (1111b); and each second silicon steel sheet (112) has a shape consistent with the main body portion (111a) of the first silicon steel sheet, so that when the first silicon steel sheet and the second silicon steel sheet are in a stacked state, the second slot wall (1111b) of each through slot (1111) is flush with the corresponding peripheral wall section (1121) of the second silicon steel sheet (112).

2. The rotor core according to claim 1, characterized in that: A protrusion (1112) protruding toward the second groove wall (1111b) is provided on the first groove wall (1111a) of each through groove.

3. The rotor core according to claim 2, characterized in that: The rotor core (110) includes only one first silicon steel sheet (111), and the only first silicon steel sheet is interposed between the second silicon steel sheets (112).

4. The rotor core according to claim 2, characterized in that: The rotor core (110) includes a plurality of first silicon steel sheets (111), wherein in the stacked state, the plurality of first silicon steel sheets are arranged relative to each other so that the respective through grooves (1111) are aligned one by one in the axial direction, and the plurality of first silicon steel sheets (111) are inserted between the second silicon steel sheets (112) at intervals relative to each other in the axial direction.

5. The rotor core according to any one of claims 1 to 4, characterized in that: The outer contour of the first silicon steel sheet (111) is circular, and the outer contour of the second silicon steel sheet (112) is a regular polygon, each side of the regular polygon corresponds to an outer peripheral wall section (1121) of the second silicon steel sheet; corresponding to each outer peripheral wall section (1121) of the second silicon steel sheet, the first silicon steel sheet (111) is provided with a through groove (1111) for a rotor magnet (120) to pass through.

6. The rotor core according to any one of claims 1 to 4, characterized in that: The second number of the second silicon steel sheets (112) is greater than the first number of the first silicon steel sheets (111).

7. A rotor assembly, characterized in that: The rotor assembly comprises a plurality of rotor magnets (120) and a rotor core (110) according to any one of claims 1 to 6, wherein each rotor magnet passes through a corresponding through slot of the first silicon steel sheet.

8. The rotor assembly according to claim 7, characterized in that The rotor core and the rotor magnet are formed into an integral piece by plastic overmolding.

9. A motor, characterized in that: The electric machine comprises a rotor assembly according to claim 7 or 8.

10. An electronic pump, characterized in that: The electronic pump comprises the electric motor according to claim 9.

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