Rotor assembly

Abstract

The invention relates to a rotor assembly which is provided with a circumferential symmetrical structure and comprises a shaft, a main magnetic ring, a Hall magnetic ring and an injection molding structure, the shaft is a metal flat shaft extending in the axial direction and is provided with knurls, and the injection molding structure is connected with the shaft in a matched mode through the knurls. The main magnet ring and the Hall magnet ring are fixedly connected to the shaft at a distance from each other by means of a slot key structure through an injection molding structure. According to the rotor assembly, the structure is simple, the number of parts is small, cost is low, assembling steps are simple, and mass production is facilitated. Moreover, according to the rotor assembly, the production stability is high, the weight of the rotor is light, and lightweight design is facilitated.

Description

Technical Field

[0001] The present invention relates to an electric motor, and more particularly to a rotor assembly. Background Art

[0002] At present, most of the rotor assemblies of brushless motors on the market use silicon steel laminations as the iron core, then use sintered neodymium iron boron magnetic tiles as permanent magnets, and complete the assembly by means of glue bonding. Such rotor assemblies use a large amount of metal and rare earth materials, resulting in high costs; using glue bonding, the process cycle time is long and the process consistency is difficult to guarantee, and dynamic balance correction is required by means of counterweight after assembly; the rotor assembly uses a large amount of metal, which is not conducive to the lightweight design of the motor, and the rotor inertia will increase accordingly, resulting in a long response time of the motor. Summary of the Invention

[0003] In order to solve the problems such as high cost in the above-mentioned prior art, the present invention provides a rotor assembly.

[0004] The rotor assembly according to the present invention has a circumferentially symmetric structure and includes a shaft, a main magnetic ring, a Hall magnetic ring and an injection molding structure. Among them, the shaft is a metal flat shaft extending axially and has knurling, the injection molding structure is connected to the shaft through the knurling, and the main magnetic ring and the Hall magnetic ring are fixedly connected to the shaft through the injection molding structure at intervals from each other by means of a keyway structure.

[0005] Preferably, the magnetic fields of the main magnetic ring and the Hall magnetic ring are circumferentially aligned.

[0006] Preferably, the main magnetic ring and the Hall magnetic ring respectively have a counterbore with a circumferentially symmetric design, and the injection molding structure has a key structure, and the counterbore is connected to the key structure in a matching manner.

[0007] Preferably, the key structures are circumferentially aligned.

[0008] Preferably, the counterbore is a square groove.

[0009] Preferably, the main magnetic ring and the Hall magnetic ring respectively have an inner ring structure, and the counterbore is arranged on the two axial end faces of the inner ring structure.

[0010] Preferably, the main magnetic ring and the Hall magnetic ring respectively have an outer ring structure integrally formed with the inner ring structure. Among them, the outer ring structure is located outside the inner ring structure and extends beyond the two axial end faces of the inner ring structure.

[0011] Preferably, the injection molding structure includes an integrally formed main body and two convex ring structures. Among them, the main body covers the outside of the shaft and is connected through the knurling, and the convex ring structures respectively radially extend from the main body to connect the main magnetic ring and the Hall magnetic ring.

[0012] Preferably, the convex ring structures respectively have two flanges, the key structures extend from the two flanges towards each other, and the part of the outer ring structure that extends beyond the inner ring structure cooperates with the flanges.

[0013] Preferably, the injection molding structure is provided by polyphenylene sulfide.

[0014] The rotor assembly according to the present invention has a simple structure, fewer parts, low cost, simple assembly steps, and is conducive to mass production. Moreover, the rotor assembly according to the present invention has high production stability, light rotor weight, and is conducive to lightweight design. Further, the rotor assembly according to the present invention has a high dynamic balance level in integral injection molding, which is beneficial to the motor noise performance and increases the competitiveness of the seat motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is an assembly schematic diagram of a rotor assembly according to a preferred embodiment of the present invention.

[0016] Figure 2 is Figure 1 a cross-sectional view of the rotor assembly.

[0017] Figure 3 is Figure 1 a schematic structural diagram of the shaft.

[0018] Figure 4 is Figure 1 a schematic structural diagram of the main magnetic ring.

[0019] Figure 5 is Figure 1 a schematic structural diagram of the Hall magnetic ring.

[0020] Figure 6 is Figure 1 a schematic structural diagram of the injection molding structure. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] The following will give and describe in detail the preferred embodiments of the present invention in conjunction with the accompanying drawings.

[0022] As Figure 1 - Figure 2 shown, the rotor assembly according to a preferred embodiment of the present invention has a circumferentially symmetric structure, and specifically includes a shaft 1, a main magnetic ring 2, a Hall magnetic ring 3, and an injection molding structure 4. Among them, the main magnetic ring 2 and the Hall magnetic ring 3 are fixedly connected to the shaft 1 through the injection molding structure 4 at intervals. In the specific production process, the shaft 1, the main magnetic ring 2, and the Hall magnetic ring 3 are connected together by injection molding using the injection molding structure 4, that is, the shaft 1 is fixed to the plastic of the injection molding structure 4, the main magnetic ring 2 is fixed to the plastic of the injection molding structure 4, and the Hall magnetic ring 3 is fixed to the plastic of the injection molding structure 4, and the overall structure is stable. Thus, the production process of the rotor assembly according to the present invention only has one injection molding step, with a fast production beat and high process consistency.

[0023] In particular, according to the circumferential symmetric structure of the rotor assembly of the present invention, the dynamic balance of the rotor is ensured, and there is no need for subsequent dynamic balance correction work, no need to add counterweights to correct the dynamic balance, the production beat is fast, and the process cost is low. Moreover, according to the rotor assembly of the present invention, it has a double magnetic ring (main magnetic ring 2 and Hall magnetic ring 3) structure and can be applied to both inductive and non-inductive brushless motors. Specifically, the magnetic fields of the main magnetic ring 2 and the Hall magnetic ring 3 are circumferentially aligned to meet the motor design envelope requirements. Compared with the prior art of silicon steel laminated cores, the rotor assembly according to the present invention has fewer parts, uses a plastic injection structure 4 instead, is light in weight and low in cost. Specifically, the injection structure 4 is provided by polyphenylene sulfide (PPS), and the mechanical stability provided by it can avoid the problem that the thermal expansion and contraction of the plastic cause stress on the magnetic ring and lead to cracking of the magnetic ring.

[0024] As Figure 3 shown, the shaft 1 is a flat shaft extending axially. Compared with a stepped shaft, the shaft structure of the flat shaft of the present invention is simpler, lighter, and has a lower manufacturing process and cost. Specifically, the shaft 1 is a metal shaft and has knurling 11, and the injection structure 4 is connected to the shaft 1 through the knurling 11. During the injection process, the plastic and the knurling 11 are filled and matched for axial and circumferential positioning. In this way, the structure of the knurling 11 is tightly buckled and adhered to the plastic of the injection structure 4 to provide axial and circumferential forces. In particular, the knurling 11 has a circumferential symmetric design, which is beneficial to reducing the dynamic unbalance amount. Compared with the prior art of threaded connection, the threaded structure will cause an increase in the dynamic unbalance amount. In this embodiment, the knurling 11 is a reticulated knurling with a length of 10 mm. In addition, the shaft 1 has a counterbore 12 for external connection to output torque. In this embodiment, the counterbore 12 is a square hole. It should be understood that other shapes such as hexagonal holes are also possible, but the processing difficulty of the corresponding shaft 1 and the connecting shaft mating with the shaft 1 will make their costs higher.

[0025] As Figure 4 shown, the main magnetic ring 2 includes an integrally formed first inner ring structure 21 and a first outer ring structure 22. Among them, the first outer ring structure 22 is located outside the first inner ring structure 21 and extends beyond the two axial end faces of the first inner ring structure 21. Specifically, the two axial end faces of the first inner ring structure 21 respectively have four first counterbores 211, and the injection structure 4 is connected to the main magnetic ring 2 through the first counterbores 211 to achieve circumferential and axial positioning. During the injection process, the plastic and the first counterbores 211 are filled and matched for axial and circumferential positioning. In this way, the structure of the first counterbores 211 is tightly buckled and adhered to the plastic of the injection structure 4 to provide axial and circumferential forces. In particular, the first counterbores 211 have a circumferential symmetric design, which is beneficial to reducing the dynamic unbalance amount. In this embodiment, the first counterbores 211 are square grooves, providing a maximum torque of 0.6 Nm. It should be understood that the square groove is the simplest to manufacture and has the lowest cost.

[0026] As Figure 5 shown, the Hall magnetic ring 3 includes an integrally formed second inner ring structure 31 and a second outer ring structure 32. Among them, the second outer ring structure 32 is located outside the second inner ring structure 31 and extends beyond the two axial end faces of the second inner ring structure 31. Specifically, each of the two axial end faces of the second inner ring structure 31 has four second sinking grooves 311. The injection molding structure 4 is connected with the Hall magnetic ring 3 through the second sinking grooves 311 to achieve circumferential and axial positioning. During the injection molding process, the plastic is filled and fitted with the second sinking grooves 311 for axial and circumferential positioning. In this way, the structure of the second sinking grooves 311 is tightly buckled and adhered to the plastic of the injection molding structure 4 to provide axial force and circumferential force. Particularly, the second sinking grooves 311 have a circumferentially symmetric design, which is beneficial to reducing the dynamic unbalance amount. In this embodiment, the second sinking grooves 311 are square grooves, providing a maximum torque of 0.6 Nm. It should be understood that the square grooves are the simplest to manufacture and process and have the lowest cost.

[0027] As Figure 6 shown, the injection molding structure 4 includes an integrally formed main body 41, a first convex ring structure 42 and a second convex ring structure 43. Among them, the main body 41 is wrapped around the outside of the shaft 1 and is connected through knurling 11 (see Figure 3 ). The first convex ring structure 42 radially extends from the first position of the main body 41 to connect to the main magnetic ring 2 (see Figure 2 ), and the second convex ring structure 43 radially extends from the second position of the main body 41 to connect to the Hall magnetic ring 3 (see Figure 2 ).

[0028] As Figure 6 shown, the first convex ring structure 42 includes a third inner ring structure 421, connecting ribs 422 and a first flange 423. Among them, the inner side of the third inner ring structure 421 is fixedly connected to the main body 41 through four connecting ribs 422 that are circumferentially spaced apart from each other. The two axial end faces on the outer side of the third inner ring structure 421 radially extend outward respectively to form the first flange 423. The two first flanges 423 have first key structures 424 that extend towards each other. Combining Figure 4 , the first inner ring structure 21 of the main magnetic ring 2 is fitted with the third inner ring structure 421, the part of the first outer ring structure 22 that exceeds the first inner ring structure 21 is fitted with the first flange 423, and the first sinking groove 211 is connected with the first key structure 424. In this embodiment, the connecting ribs 422 and the first key structures 424 are aligned in the circumferential direction.

[0029] As Figure 6As shown, the second convex ring structure 43 includes a fourth inner ring structure 431 and a second flange 432. Among them, the inner side of the fourth inner ring structure 431 is directly fixedly connected to the main body 41. The two axial end faces on the outer side of the fourth inner ring structure 431 respectively extend radially outward to form the second flange 432. The two second flanges 432 have second key structures 433 extending towards each other. Combining Figure 5 , the second inner ring structure 31 of the Hall magnetic ring 3 cooperates with the fourth inner ring structure 431, the part of the second outer ring structure 32 that exceeds the second inner ring structure 31 cooperates with the second flange 432, and the second sink 311 is cooperatively connected with the second key structure 433. In this embodiment, the first key structure 424 and the second key structure 433 are aligned in the circumferential direction.

[0030] The above is only the preferred embodiment of the present invention and is not intended to limit the scope of the present invention. Various changes can be made to the above embodiments of the present invention. That is, all simple, equivalent changes and modifications made according to the claims and the content of the specification of the present invention application fall within the scope of the claims of the present invention patent. The conventional technical content is not described in detail in the present invention.

Claims

1. A rotor assembly, characterized in that, the rotor assembly has a circumferentially symmetric structure, including a shaft, a main magnetic ring, a Hall magnetic ring and an injection molding structure. Among them, the shaft is a metal flat shaft extending axially and has knurling. The injection molding structure is connected to the shaft through the knurling. The main magnetic ring and the Hall magnetic ring are fixedly connected to the shaft through the injection molding structure at intervals from each other by means of a keyway structure.

2. The rotor assembly according to claim 1, characterized in that, the magnetic fields of the main magnetic ring and the Hall magnetic ring are circumferentially aligned.

3. The rotor assembly according to claim 1, characterized in that, the main magnetic ring and the Hall magnetic ring respectively have counterbores with a circumferentially symmetric design. The injection molding structure has a key structure, and the counterbores are connected in cooperation with the key structure.

4. The rotor assembly according to claim 3, characterized in that, the key structures are circumferentially aligned.

5. The rotor assembly according to claim 3, characterized in that, the counterbore is a square groove.

6. The rotor assembly according to claim 3, characterized in that, the main magnetic ring and the Hall magnetic ring respectively have an inner ring structure, and the counterbores are arranged on the two axial end faces of the inner ring structure.

7. The rotor assembly according to claim 6, characterized in that, the main magnetic ring and the Hall magnetic ring respectively have an outer ring structure integrally formed with the inner ring structure. Among them, the outer ring structure is located outside the inner ring structure and extends beyond the two axial end faces of the inner ring structure.

8. The rotor assembly according to claim 7, characterized in that, the injection molding structure includes an integrally formed main body and two convex ring structures. Among them, the main body is wrapped outside the shaft and is connected in cooperation through the knurling. The convex ring structures respectively radially extend from the main body to connect the main magnetic ring and the Hall magnetic ring.

9. The rotor assembly according to claim 8, characterized in that, the convex ring structures respectively have two flanges, the key structures extend from the two flanges towards each other, and the part of the outer ring structure that extends beyond the inner ring structure cooperates with the flanges.

10. The rotor assembly according to claim 1, characterized in that, the injection molding structure is provided by polyphenylene sulfide.

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