Rotor assembly, motor and electronic pump

Abstract

The utility model relates to a rotor core, rotor magnets and a holder used for fixedly holding a plurality of rotor magnets, the rotor core is provided with a plurality of radial grooves at intervals along the circumferential direction, and the holder comprises an integrally formed bottom supporting surface and a circumferential surface vertically extending from the bottom supporting surface. A plurality of supporting ribs spaced apart from each other in the circumferential direction are formed on the radial inner side of the circumferential surface, and each supporting rib is engaged in a corresponding radial groove of the rotor core; each rotor magnet is jointed in a gap which is jointly limited by the circumferential surface of the retainer, the outer circumferential surface of the rotor core and two adjacent supporting ribs, the end part, far away from the bottom supporting surface, of each supporting rib is provided with a stop flange, and the rotor magnets and the rotor core can be kept in the retainer through the stop flanges and the bottom supporting surface. The utility model also relates to a motor and an electronic pump. The rotor assembly, the motor or the electronic pump according to the utility model is more cost-effective.

Description

TECHNICAL FIELD

[0001] The utility model relates to motor technical field, concretely relates to a rotor assembly, the motor including the rotor assembly and the electronic pump including this kind of motor. BACKGROUND

[0002] In brushless motor, the rotor with surface-mounted magnet is usually adopted, the surface-mounted magnet can be kept on the outer periphery of the rotor core formed by silicon steel sheet stacking through the retainer, and then the rotor core, magnet and retainer are injected and wrapped together for fixation.

[0003] As in the technical solution known in the prior art, a plastic holder is usually provided to keep the magnet between the plastic holder and the outer peripheral surface of the rotor core in the radial direction. However, this solution usually requires a secondary injection wrapping process to complete the fixation assembly of the entire rotor assembly by using the injection housing. However, the injection mold is relatively high in cost and is inconvenient to assemble, and since the magnet needs to be inserted between the silicon steel sheet and the plastic holder, a certain gap is often left between the plastic holder and the silicon steel sheet, and the gap is too large to cause the magnet to be loose after assembly, which causes the magnet to slip or even fall 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 performance, and if the gap is designed to be too small, it will cause the magnet to be difficult or impossible to insert and the magnet surface to be severely scratched. Therefore, an improved fixing structure for the rotor magnet needs to be proposed. SUMMARY

[0004] The utility model aims at solving at least one of the above problems and / or other problems in the prior art.

[0005] According to one aspect of the utility model, a rotor assembly is provided, which comprises a rotor core, a plurality of rotor magnets and a retainer for fixedly retaining the plurality of rotor magnets, the rotor core is formed with a plurality of radial grooves spaced apart from each other in the circumferential direction, the retainer comprises an integrally formed bottom supporting surface and a circumferential surface extending perpendicularly from the bottom supporting surface, a plurality of supporting ribs spaced apart from each other in the circumferential direction are formed on the radial inner side of the circumferential surface, and each supporting rib is engaged in the corresponding radial groove of the rotor core; wherein each rotor magnet is engaged in the gap defined by the circumferential surface of the retainer, the outer peripheral surface of the rotor core and the adjacent two supporting ribs, and the end of each supporting rib away from the bottom supporting surface is provided with a stop flange, and the rotor magnet and the rotor core can be tightly retained in the retainer through the stop flange and the bottom supporting surface.

[0006] As an embodiment, the rotor core is formed by a plurality of silicon steel sheets stacked in an axial direction, each silicon steel sheet being formed with a plurality of radial notches spaced apart from each other in a circumferential direction, the radial notches of each silicon steel sheet aligned in the axial direction forming radial grooves of the rotor core when the plurality of silicon steel sheets are stacked on each other.

[0007] As an embodiment, the stopper flange extends and is attached to the rotor core and the rotor magnet.

[0008] As an embodiment, the stopper flange is formed by hot forming a portion of material at the end portion of the support rib distal from the bottom support surface.

[0009] As an embodiment, the stopper flange is formed by hot staking.

[0010] As an embodiment, the retainer is formed as a one-piece by plastic injection molding.

[0011] As an embodiment, the bottom support surface is in the form of an annular surface having a central opening.

[0012] As an embodiment, the support rib has a radial extension length that is no greater than a radial width of the bottom support surface.

[0013] According to another aspect of the present application, a motor is provided, the motor including a rotor assembly as described above.

[0014] According to yet another aspect of the present application, an electronic pump is provided, the electronic pump including a motor as described above.

[0015] According to the rotor assembly of the present application, by employing a one-piece retainer with a bottom support surface, and by hot forming, for example, hot staking, an end portion of the retainer, a stopper flange that can be attached to an end surface of the rotor core and the rotor magnet can be formed using the hot deformed plastic material, thereby fixing the rotor magnet and the silicon steel sheets in the retainer using the stopper flange and the bottom support surface, which makes it possible to cancel a secondary injection molding process after assembly, thereby having an advantage in terms of injection molding mold, material, and part costs and facilitating assembly, while avoiding an undesirable process hole required by the secondary injection molding process, thereby avoiding a problem of corrosion of the rotor magnet due to partial exposure to external substances due to the presence of the process hole. BRIEF DESCRIPTION OF DRAWINGS

[0016] The features and advantages of the present application will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0017] Figure 1 a decomposition diagram of a rotor assembly according to an embodiment of the present application is shown;

[0018] Figure 2 a perspective view of a retainer in a rotor assembly in Figure 1

[0019] Figure 3a a perspective view of a retainer in a rotor assembly in Figure 1

[0020] Figure 3b a perspective view of a retainer in a rotor assembly in Figure 1

[0021] Figure 4a a stopper flange formed at an end portion of a support rib of the retainer after a heat riveting process is shown in a partial schematic view; and

[0022] Figure 4b a structural schematic view of an end portion of a support rib of the retainer before a heat riveting process is shown in a partial schematic view. DETAILED DESCRIPTION

[0023] Embodiments of the present application are described below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. It will be apparent, however, to one skilled in the art, that the present application can be practiced without some or all of these specific details. In other instances, well known process steps have not been described in detail in order not to unnecessarily obscure the present application. In addition, it is to be understood that the present application is not limited in its application to the particular embodiments described below. Instead, the application is capable of achieving its objects by various combinations of the features and elements set forth below using any of the various means possible within the scope of the application. Accordingly, the following aspects, features, embodiments and advantages are merely illustrative and are not required.

[0024] In the following description, terms such as "first", "second", etc. are used to describe various elements, and these terms are only used to distinguish one element from another, and are not used to limit the nature, order or number of the elements. The terms "include" and "have" are used to mean an open-ended inclusion, and refer to the presence of additional elements / components in addition to the listed elements / components.

[0025] ​​​As mentioned in the background, in the design of existing electric machines, the rotor magnets are arranged in the cage in a clearance fit, which can cause the rotor magnets to be loose after assembly, and due to the clearance, the magnetic resistance is increased and the magnetic performance is reduced. And due to the need for a secondary injection wrapping process, the cost is high. Therefore, the utility model provides an improved solution, which can be assembled in a simpler, better performing, and more cost-effective manner to retain the rotor magnets.

[0026] In particular, Figure 1 An exploded view of a rotor assembly according to an embodiment of the utility model is shown. The utility model provides an improved rotor assembly 1, which includes a rotor core 2, a plurality of rotor magnets 3, and a cage 4 for retaining the rotor magnets 3. As shown, Figure 1 The rotor core 2 can be formed, for example, by stacking a plurality of silicon steel sheets 21. Each silicon steel sheet 21 is formed with a plurality of radial notches 211 spaced apart from each other in a circumferential direction, and when the plurality of silicon steel sheets 21 are stacked on each other, the radial notches 211 of each silicon steel sheet 21 aligned in an axial direction form radial grooves 22 of the rotor core 2.

[0027] Unlike the plastic cage in the prior art, for example, see Figure 2 According to the utility model, the cage 4 includes an integrally formed bottom support surface 41 and a circumferential surface 42 extending perpendicularly from the bottom support surface 41, so that the bottom support surface 41 can provide bottom support for the rotor magnets 3 and the rotor core 2 placed in the cage 4. As shown, Figure 2 The bottom support surface 41 of the cage 4 is in the form of an annular surface with a central opening.

[0028] In addition, a plurality of support ribs 43 spaced apart from each other in a circumferential direction are formed on the radially inner side of the circumferential surface 42, and each support rib 43 is engaged in a corresponding radial groove 22 of the rotor core 2. The radial extension length of the support rib 43 (i.e., the length extending in the radial direction of the cage 4) is not greater than the radial width of the bottom support surface 41 (i.e., the distance between the inner and outer edges of the annular surface). As shown, Figure 2 The transverse cross-section of the support rib 43 includes a first portion and a second portion that are contiguous with each other, and the width of the second portion is greater than the width of the first portion, so that when the support rib 43 is engaged in the radial groove 22 of the rotor core, any radial movement of the rotor core 2 relative to the cage 4 can be prevented.

[0029] In as Figure 3aIn the final assembled rotor assembly 1 shown, each rotor magnet 3 is engaged within a gap defined by the circumferential face 42 of the holder 4, the outer circumferential surface of the rotor core 2 and two adjacent support ribs 43. In order to avoid the rotor magnets 3 from disengaging from the holder 4, the end of each support rib 43 distal to the bottom support face 41 is provided with a stop flange 431, by which the rotor magnets 3 and the rotor core 2 can be tightly held within the holder 4.

[0030] According to a specific embodiment, the stop flange 431 is formed by a portion of material of the support rib 43 at the end distal to the bottom support face by means of a hot forming, such as a hot staking. In this way, by means of the hot staking process, by hot deforming the portion of material of the holder 4 at this end so that it can extend in a flowable state and finally solidify and adhere to the end faces of the rotor core 2 and the rotor magnets 3 distal to the bottom support face 41, the holder 4, the rotor core 2 and the rotor magnets 3 are tightly held together. By means of this integrally formed holder and in combination with the hot staking process, the secondary injection-molding wrapping process can be dispensed with, greatly reducing the production manufacturing costs. Of course, other ways of causing the plastic to melt are also possible, such as with a laser or other hot forming, as long as the function intended to be achieved here is achieved.

[0031] In order to obtain such a stop flange, before the hot forming of the end of the support rib 43 of the holder 4, see for example Figure 3b and Figure 4b a protruding material portion 431' is formed at the end of the support rib 43 which protrudes a certain height h, such as about 2-3 mm, out of the circumferential face 42 of the holder 4. When assembling the rotor assembly, by placing the rotor core 2 in the holder 4 in the axial direction, the support ribs 43 pass through the respective radial recesses 22 of the rotor core 2, after the rotor core 2 is in place and stopped on the bottom support face 41 of the holder 4, see Figure 3b the protruding material portion 431' at the end of the support rib 43 can be subjected to a hot staking process, for example. At this point, the protruding material portion 431' can be melted into a flowable state and flow onto the end faces of the rotor magnets 3 and the rotor core 2 distal to the bottom support face 41 and solidify to form the stop flanges 431 adhering to the end faces of the rotor magnets 3 and the rotor core 2, as shown in Figure 3a and Figure 4a .

[0032] Since the rotor assembly according to the application dispenses with the secondary injection-molding process, the production costs of the rotor are optimized.

[0033] The utility model also relates to a motor including the improved rotor assembly, the motor has reduced cost and simple assembly, and because the rotor magnet and rotor core (such as silicon steel sheet) have reduced magnetic resistance, the magnetic performance of the motor is greatly improved. The motor according to the utility model can be applied to multiple technical fields, for example, 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 utility model is not limited to a water pump motor, but also can be other types of brushless motors and permanent magnet synchronous motors, such as a steering assist system motor, a gear shifting motor, a clutch motor, a brake motor, a gasoline pump, an oil pump and the like.

[0034] Various modifications and changes can be made to the embodiments disclosed herein without departing from the scope or spirit of the present disclosure. Other embodiments of the present disclosure will be apparent to those of ordinary skill in the art from consideration of the specification and practice of the present disclosure. The specification and examples given are intended as illustrative only and are not intended to limit the true scope of the present disclosure, which is to be set forth in the appended claims and their equivalents.

Claims

1. A rotor assembly comprising a rotor core (2), a plurality of rotor magnets (3), and a holder (4) for holding the plurality of rotor magnets (3), the rotor core (2) being formed with a plurality of radial grooves (22) at intervals from each other in a circumferential direction, characterized in that, The holder (4) comprises an integrally formed bottom support surface (41) and a circumferential surface (42) extending perpendicularly from the bottom support surface, a plurality of support ribs (43) being formed on the circumferential surface in a circumferential direction and spaced apart from each other, each support rib being engaged in a corresponding radial groove (22) of the rotor core (2); wherein each rotor magnet (3) is engaged in a gap defined by the circumferential surface (42) of the holder (4), the outer circumferential surface of the rotor core (2) and two adjacent support ribs (43), an end of each support rib (43) away from the bottom support surface (41) being provided with a stop flange (431), the rotor magnet (3) and the rotor core (2) being tightly held in the holder (4) by the stop flange (431) and the bottom support surface (41).

2. The rotor assembly of claim 1, wherein The rotor core (2) is formed by a plurality of silicon steel sheets (21) stacked in an axial direction, each silicon steel sheet (21) being formed with a plurality of radial notches (211) spaced apart from each other in a circumferential direction; when the plurality of silicon steel sheets are stacked on each other, the radial notches of each silicon steel sheet aligned in the axial direction form the radial grooves (22) of the rotor core.

3. The rotor assembly of claim 1, wherein The stop flange (431) extends and adheres to the rotor core (2) and the rotor magnet (3).

4. The rotor assembly of claim 3, wherein The stop flange (431) is formed by hot forming of a portion of material at the end of the support rib (43) away from the bottom support surface.

5. The rotor assembly of claim 4, wherein, The stop flange (431) is formed by hot riveting.

6. The rotor assembly of any one of claims 1 to 3, wherein, The holder (4) is integrally formed by plastic injection molding.

7. The rotor assembly of any one of claims 1 to 3, wherein, The bottom support surface (41) is in the form of an annular surface with a central opening.

8. The rotor assembly of claim 7, wherein, The radial extension length of the support rib (43) is not greater than the radial width of the bottom support surface (41).

9. An electric machine characterized by The motor comprises the rotor assembly (1) according to any one of claims 1 to 8.

10. An electronic pump characterized by, The electronic pump comprises the motor according to claim 9.

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