A brushless motor rotor assembly with a buffer structure

Abstract

This invention discloses a brushless motor rotor assembly with a buffer structure, including a magnet, a shaft, and a rotor housing with a shaft hole. The shaft passes through the shaft hole, and the magnet is coaxially arranged on the rotor housing. The rotor housing includes a sleeve portion with a receiving cavity and an elastic support structure integrally connected to the sleeve portion and located in the receiving cavity. The elastic support structure includes a plurality of rotor bullets arranged at equal intervals along the circumference of the shaft. One end of each rotor bullet is fixedly connected to the sleeve portion, and there is a deformation gap between adjacent rotor bullets. An elastic ring with radial elastic tension is provided in the receiving cavity. The elastic ring is sleeved on the rotor bullets and drives the inner wall of the rotor bullets to elastically abut against the outer wall of the shaft. This assembly effectively buffers radial displacement between the shaft and the rotor housing, reduces noise during brushless motor operation, extends service life, and facilitates easy installation and removal of the elastic ring.

Description

Technical Field

[0001] This invention relates to the field of brushless motor technology, and in particular to a brushless motor rotor assembly with a buffer structure. Background Technology

[0002] A brushless motor consists of a motor body and a driver, and is a typical mechatronic product. The brushless motor includes a rotor assembly, which comprises a shaft, a rotor housing rotatably mounted outside the shaft, and magnets arranged around the rotor housing. The rotor housing has a shaft hole corresponding to the shaft, and is rotatably mounted outside the shaft through this hole. In this type of brushless motor, there is a tiny gap between the inner wall of the shaft hole of the rotor housing and the outer circumference of the shaft. When the brushless motor is working, the rotor housing rotates around the shaft. However, during this rotation, the inner wall of the shaft hole of the rotor housing continuously impacts the outer wall of the shaft, generating continuous noise. Therefore, there is an urgent need to develop a brushless motor rotor assembly that can reduce the noise generated by the collision between the housing and the shaft. Summary of the Invention

[0003] The purpose of this invention is to provide a brushless motor rotor assembly with a buffer structure, which can effectively buffer radial offset between the shaft and the rotor housing, reduce noise during operation of the brushless motor, extend service life, and facilitate the installation and removal of the elastic ring.

[0004] The above-mentioned technical objective of the present invention is achieved through the following technical solution: a brushless motor rotor assembly with a buffer structure, including a magnet, a rotating shaft, and a rotor housing with a shaft hole, wherein the rotating shaft passes through the shaft hole, the magnet is coaxially arranged on the rotor housing, the rotor housing includes a sleeve portion with a receiving cavity, and an elastic support structure integrally connected to the sleeve portion and located in the receiving cavity, the elastic support structure including a plurality of rotating bullet pieces arranged at equal intervals along the circumference of the rotating shaft, one end of the rotating bullet pieces being fixedly connected to the sleeve portion, and a deformation gap being present between adjacent rotating bullet pieces;

[0005] The cavity is provided with an elastic ring having radial elastic tension. The elastic ring is sleeved on the outside of a plurality of rotating bullet pieces and drives the inner wall of the rotating bullet pieces to elastically abut against the outer wall of the rotating shaft.

[0006] By adopting the above technical solution, when the rotor housing drives the magnet to rotate relative to the shaft, the elastic deformation force of the rotor blades can buffer the impact caused by radial displacement between the shaft and the rotor housing. At the same time, the tension force of the elastic ring on the radial direction of the rotor blades ensures that the rotor housing and the shaft always maintain a high degree of concentricity, thereby avoiding resonance caused by continuous shaking between the shaft and the rotor housing. This effectively suppresses the noise during the operation of the brushless motor, reduces the wear rate between the shaft and the rotor housing, and extends the service life of the rotor assembly. In addition, the elastic ring adopts a detachable installation method, which facilitates the removal and replacement of the elastic ring. At the same time, both the rotor blades and the elastic ring are located in the receiving cavity, which can effectively improve the structural compactness of the rotor assembly. It has the effects of effectively buffering the radial displacement between the shaft and the rotor housing, reducing the noise during the operation of the brushless motor, extending the service life, and facilitating the removal and installation of the elastic ring.

[0007] A further feature of the present invention is that the elastic ring is configured as a cylindrical structure, and the ring wall of the elastic ring is configured with a uniform thickness.

[0008] By adopting the above technical solution, the elastic force of the elastic ring with equal thickness is equal at all positions of the ring wall, and the radial tightening force is consistent at all positions along the length of the rotating bullet piece. The deformation controllability and fatigue resistance are higher, which can significantly reduce the risk of local stress concentration caused by abrupt changes in cross-section and avoid the occurrence of microcracks on the surface of the elastic ring when the brushless motor is working under high load.

[0009] A further feature of the present invention is that the elastic ring is made of an elastic polymer material.

[0010] A further provision of the present invention is that a clearance space is provided between the outer wall of the elastic ring and the inner wall of the receiving cavity.

[0011] By adopting the above technical solution and reserving space, the ease of installation and removal of the elastic ring within the cavity is improved.

[0012] A further configuration of the present invention is as follows: the rotating bullet includes a fixed end and a free end, and the inner wall of the sleeve extends inwardly corresponding to the fixed end, with a connecting portion extending inwardly, and the fixed end is fixedly connected to the inner wall of the sleeve through the connecting portion.

[0013] By adopting the above technical solution, the connecting part serves as the connection point for fixing the rotor bullet, which can improve the machining position accuracy of the rotor bullet. In addition, the rotor bullet can also transfer the load to the sleeve part through the connecting part, eliminating local stress concentration and reducing the risk of rotor shell deformation.

[0014] A further feature of the present invention is that the connection between the fixed end of the rotating bullet piece and the connecting part adopts an arc transition.

[0015] By adopting the above technical solution, the arc transition connection method can effectively avoid stress concentration at the connection position.

[0016] A further feature of the present invention is that: the inner surface of the rotating bullet is provided with a rotating contact surface corresponding to the outer wall of the rotating shaft, the rotating contact surface extends from the free end toward the fixed end, and the rotating bullet rotates in cooperation with the rotating shaft through the rotating contact surface;

[0017] The rotating shaft has a detached state and an assembled state relative to the shaft hole. When the rotating shaft is in the detached state relative to the shaft hole, the distance between the rotating contact surfaces of any two rotating bullet pieces gradually decreases from the fixed end to the free end.

[0018] When the rotating shaft and the shaft hole are in the assembled state, the rotating shaft squeezes several rotating bullet pieces to open radially outward, so that the several rotating bullet pieces squeeze the rotating shaft radially inward, and drive the rotating shaft and the shaft hole to maintain or move to a concentric position.

[0019] By adopting the above technical solution, when the rotating shaft is inserted into the shaft hole, the rotating bullets located around the shaft hole are squeezed outward by the rotating shaft, causing the rotating bullets to undergo elastic deformation. The rotating bullets have an inward elastic restoring contraction force. This elastic force reacts on the outer wall of the rotating shaft. By utilizing the combined squeezing force of multiple sets of rotating bullets acting simultaneously on the outer wall of the rotating shaft, the axis of the rotating shaft and the shaft hole can be maintained or moved to a concentric position, thereby effectively suppressing the radial displacement of the rotor housing relative to the rotating shaft.

[0020] A further feature of the present invention is that the edge of the rotating contact surface near the fixed end is smoothly connected to the opening edge of the corresponding side of the shaft hole.

[0021] By adopting the above technical solution and the smooth transition connection method, the shaft can be inserted into the shaft hole more smoothly through the rotating mating surface.

[0022] A further feature of the present invention is that the inner wall of the rotating bullet on the free end side is provided with a guide slope, the rotating shaft is guided and engaged with the rotating contact surface through the guide slope, and the inclination angle α of the guide slope relative to the rotating shaft is set to be between 5-40°.

[0023] By adopting the above technical solution, the addition of the guide slope allows the rotating shaft to slide quickly through the guide slope to the rotating contact surface of the rotating bullet without precise alignment, and finally be inserted into the shaft hole.

[0024] A further feature of the present invention is that: the upper and lower ends of the rotor housing extend radially outward to form annular anti-detachment portions, and an installation groove is formed between the two annular anti-detachment portions on the outer wall of the rotor housing; the magnet is configured as an annular structure, and the magnet is installed on the rotor housing through the installation groove, with both ends of the magnet engaging with the corresponding annular anti-detachment portions for anti-detachment.

[0025] By adopting the above technical solution, the magnet anti-rotation is installed in the mounting groove of the rotor housing, thus preventing the magnet from shifting when the rotor housing rotates at high speed.

[0026] In summary, the present invention has the following beneficial effects:

[0027] This design employs a system where several rotating bullets are integrally installed within the sleeve portion of the rotor housing. The rotating shaft passes through the shaft hole of the rotor housing, and an elastic ring is fitted over the rotating bullets. When the rotor housing drives the magnet to rotate relative to the rotating shaft, the elastic deformation force of the rotating bullets buffers the impact caused by radial displacement between the rotating shaft and the rotor housing. Simultaneously, the tension force of the elastic ring on the rotating bullets in the radial direction ensures that the rotor housing and the rotating shaft maintain a high degree of concentricity, thus preventing resonance caused by continuous shaking between the rotating shaft and the rotor housing. This effectively suppresses noise during brushless motor operation, reduces the wear rate between the rotating shaft and the rotor housing, and extends the service life of the rotor assembly. Furthermore, the elastic ring is installed in a detachable, sleeved manner, facilitating its removal and replacement. Since both the rotating bullets and the elastic ring are located within a receiving cavity, this effectively improves the structural compactness of the rotor assembly. The design effectively buffers radial displacement between the rotating shaft and the rotor housing, reduces noise during brushless motor operation, extends service life, and facilitates easy removal and installation of the elastic ring. Attached Figure Description

[0028] Figure 1 This is a structural diagram of the rotor assembly of the present invention.

[0029] Figure 2 This is the present invention. Figure 1 Top view.

[0030] Figure 3 This is the present invention. Figure 2 A sectional view of section AA in the middle.

[0031] Figure 4 This is the present invention. Figure 1 Exploded view.

[0032] Figure 5 This is a top view of the rotor assembly of the present invention after the rotor has been removed from the shaft.

[0033] Figure 6 This is the present invention. Figure 5 Sectional view of section BB.

[0034] In the diagram: 1. Rotor housing; 11. Shaft hole; 12. Mounting groove; 13. Gear section; 14. Anti-rotation groove; 15. Annular anti-detachment section; 2. Sleeve section; 21. Receiving cavity; 22. Clearance space; 23. Connecting section; 3. Rotary bullet plate; 30. Deformation gap; 31. Fixed end; 32. Free end; 321. Guide slope; 33. Rotation contact surface; 4. Elastic ring; 5. Magnet; 51. Anti-rotation protrusion; 6. Rotating shaft. Detailed Implementation

[0035] The invention will now be further described with reference to the accompanying drawings.

[0036] A brushless motor rotor assembly with a buffer structure, such as Figures 1-4 As shown, the rotor housing includes a magnet 5, a rotating shaft 6, and a rotor shell 1 with a shaft hole 11. The rotor shell 1 is made of plastic, and the rotating shaft 6 is made of metal. The rotating shaft 6 passes through the shaft hole 11. The magnet 5 is coaxially arranged on the rotor shell 1. The rotor shell 1 includes a sleeve portion 2 with a receiving cavity 21 and an elastic support structure integrally connected to the sleeve portion 2 and located in the receiving cavity 21. The elastic support structure includes a plurality of rotating bullet pieces 3 arranged at equal intervals along the circumference of the rotating shaft 6. One end of the rotating bullet piece 3 is fixedly connected to the sleeve portion 2, and there is a deformation gap 30 between adjacent rotating bullet pieces 3. An elastic ring 4 with radial elastic tension is provided in the receiving cavity 21. The elastic ring 4 is sleeved on the outside of the plurality of rotating bullet pieces 3 and drives the inner wall of the rotating bullet pieces 3 to elastically abut against the outer wall of the rotating shaft 6. The upper and lower ends of the rotor shell 1 are radially oriented towards An annular anti-detachment part 15 is formed by extending outwards. An installation groove 12 is formed on the outer wall of the rotor housing 1 between the two annular anti-detachment parts 15. The magnet 5 is designed as an annular structure. The magnet 5 is installed on the rotor housing 1 through the installation groove 12, and the two ends of the magnet 5 are anti-detached from the corresponding annular anti-detachment part 15, so that the magnet 5 is installed in the installation groove 12 of the rotor housing 1 to prevent rotation, thus preventing the magnet 5 from shifting when the rotor housing 1 rotates at high speed. The magnet 5 is provided with an anti-rotation protrusion 51. The rotor housing 1 is provided with an anti-rotation groove 14 that communicates with the installation groove 12. The anti-rotation protrusion 51 and the anti-rotation groove 14 are positioned to prevent rotation, so that the magnet 5 is installed in the installation groove 12 of the rotor housing 1 to prevent rotation, thus preventing the magnet 5 from shifting when the rotor housing 1 rotates at high speed. In addition, in this embodiment, a gear part 13 is integrally provided at the output end of the rotor housing 1.

[0037] like Figures 3-6As shown, the rotor blade 3 includes a fixed end 31 and a free end 32. A connecting portion 23 extends inward from the inner wall of the sleeve portion 2 corresponding to the fixed end 31. The fixed end 31 is fixedly connected to the inner wall of the sleeve portion 2 via the connecting portion 23. The connection between the fixed end 31 and the connecting portion 23 of the rotor blade 3 adopts an arc transition. This arc transition effectively avoids stress concentration at the connection point. The connecting portion 23, as the connection point of the fixed end 31 of the rotor blade 3, can improve the machining position accuracy of the rotor blade 3. Furthermore, the rotor blade 3 can also transfer the load to the sleeve portion 2 through the connecting portion 23, eliminating local stress concentration and reducing the deformation of the rotor housing 1. The inner surface of the rotating bullet piece 3 is provided with a rotating contact surface 33 corresponding to the outer wall of the rotating shaft 6. The rotating contact surface 33 is an arc-shaped groove surface that is recessed towards the inner wall of the rotating bullet piece 3. The rotating contact surface 33 extends from the free end 32 towards the fixed end 31. The rotating bullet piece 3 rotates and engages with the rotating shaft 6 through the rotating contact surface 33. The rotating shaft 6 has a withdrawn state and an assembled state relative to the shaft hole 11. When the rotating shaft 6 is in the withdrawn state relative to the shaft hole 11, the distance between any two rotating contact surfaces 33 of the rotating bullet pieces 3 gradually decreases from the fixed end 31 towards the free end 32. When the rotating shaft 6 is in the assembled state with the shaft hole 11, the rotating shaft 6 compresses several rotating bullet pieces 3 radially. The rotating bullets 3 open outwards, causing several rotating bullet pieces 3 to radially press inwards against the rotating shaft 6, thus maintaining or moving the rotating shaft 6 and the shaft hole 11 to a concentric position. When the rotating shaft 6 is inserted into the shaft hole 11, the rotating bullet pieces 3 located around the shaft hole 11 are pressed outwards by the rotating shaft 6, causing the rotating bullet pieces 3 to undergo elastic deformation. The rotating bullet pieces 3 have an inward elastic restoring contraction force, which reacts on the outer wall of the rotating shaft 6. The combined pressing force of multiple sets of rotating bullet pieces 3 acting simultaneously on the outer wall of the rotating shaft 6 drives the axis of the rotating shaft 6 and the shaft hole 11 to maintain or move to a concentric position, thereby effectively suppressing the radial displacement of the rotor housing 1 relative to the rotating shaft 6; rotational fit. The edge of the surface 33 near the fixed end 31 is smoothly connected to the opening edge of the corresponding side of the shaft hole 11. This smooth transition makes it easier for the rotating shaft 6 to be inserted into the shaft hole 11 through the rotating contact surface 33. The inner wall of the rotating bullet 3 located on the free end 32 side is provided with a guide slope 321. The rotating shaft 6 is guided and engaged with the rotating contact surface 33 through the guide slope 321. The inclination angle α of the guide slope 321 relative to the rotating shaft 6 is set between 5-40°. The addition of the guide slope 321 allows the rotating shaft 6 to slide quickly through the guide slope 321 onto the rotating contact surface 33 of the rotating bullet 3 without precise alignment, and finally be inserted into the shaft hole 11.

[0038] like Figures 1-4As shown, the elastic ring 4 is designed as a cylindrical structure with a uniform wall thickness. The uniform thickness and elastic force of the elastic ring 4 at all positions of the wall result in consistent radial tightening force at all positions along the length of the rotating bullet piece 3. This improves the controllability of deformation and fatigue resistance, significantly reducing the risk of local stress concentration caused by abrupt changes in cross-section and preventing micro-cracks from appearing on the surface of the elastic ring 4 when the brushless motor is under high load. The elastic ring 4 is made of elastic polymer material. A clearance space 22 is provided between the outer wall of the elastic ring 4 and the inner wall of the receiving cavity 21. The provision of the clearance space 22 improves the ease of installation and disassembly of the elastic ring 4 within the receiving cavity 21.

[0039] The basic working principle of this invention is as follows: A plurality of rotating bullet pieces 3 are integrally arranged inside the sleeve portion 2 of the rotor housing 1. The rotating shaft 6 is inserted into the shaft hole 11 of the rotor housing 1, and an elastic ring 4 is fitted over the rotating bullet pieces 3. When the rotor housing 1 drives the magnet 5 to rotate relative to the rotating shaft 6, the elastic deformation force of the rotating bullet pieces 3 can buffer the impact caused by the radial displacement between the rotating shaft 6 and the rotor housing 1. Simultaneously, the tension force of the elastic ring 4 on the rotating bullet pieces 3 in the radial direction ensures that the rotor housing 1 and the rotating shaft 6 maintain a high degree of concentricity, thereby preventing the rotating shaft 6 from being held together with the rotor housing 1. The continuous shaking and resonance effectively suppresses the noise of the brushless motor during operation, reduces the wear rate between the shaft 6 and the rotor housing 1, and extends the service life of the rotor assembly. In addition, the elastic ring 4 adopts a detachable installation method, which facilitates the disassembly and replacement of the elastic ring 4. At the same time, both the rotor bullet 3 and the elastic ring 4 are located in the receiving cavity 21, which can effectively improve the structural compactness of the rotor assembly. It has the effects of effectively buffering the radial displacement between the shaft and the rotor housing, reducing the noise of the brushless motor during operation, extending the service life, and facilitating the disassembly and assembly of the elastic ring.

[0040] The above description is only a preferred embodiment of the present invention. Therefore, all equivalent changes or modifications made to the structure, features and principles described in the claims of this patent application are included in the scope of this patent application.

Claims

1. A brushless motor rotor assembly with a buffer structure, comprising a magnet (5), a shaft (6), and a rotor housing (1) having a shaft hole (11), wherein the shaft (6) passes through the shaft hole (11), and the magnet (5) is coaxially arranged on the rotor housing (1), characterized in that: The rotor housing (1) includes a sleeve portion (2) having a receiving cavity (21) and an elastic support structure integrally connected to the sleeve portion (2) and located in the receiving cavity (21). The elastic support structure includes a plurality of rotating bullet pieces (3) arranged circumferentially along the rotating shaft (6). One end of the rotating bullet piece (3) is fixedly connected to the sleeve portion (2), and there is a deformation gap (30) between adjacent rotating bullet pieces (3). The cavity (21) is provided with an elastic ring (4) having radial elastic tension. The elastic ring (4) is sleeved on the outside of a plurality of rotating bullet pieces (3) and drives the inner wall of the rotating bullet pieces (3) to elastically abut against the outer wall of the rotating shaft (6).

2. A brushless motor rotor assembly having a cushioning structure according to claim 1, characterized in that: The elastic ring (4) is configured as a cylindrical structure, and the ring wall of the elastic ring (4) is set with equal thickness.

3. A brushless motor rotor assembly having a cushioning structure according to claim 1, characterized in that: The elastic ring (4) is made of elastic polymer material.

4. A brushless motor rotor assembly having a cushioning structure according to claim 1, characterized in that: A clearance space (22) is provided between the outer wall of the elastic ring (4) and the inner wall of the receiving cavity (21).

5. A brushless motor rotor assembly having a cushioning structure according to claim 1, characterized in that: The rotating bullet (3) includes a fixed end (31) and a free end (32). The inner wall of the sleeve (2) extends inward to the fixed end (31) with a connecting part (23). The fixed end (31) is fixedly connected to the inner wall of the sleeve (2) through the connecting part (23).

6. A brushless motor rotor assembly having a cushioning structure according to claim 5, characterized in that: The connection between the fixed end (31) of the rotating bullet piece (3) and the connecting part (23) adopts an arc transition.

7. A brushless motor rotor assembly having a cushioning structure according to claim 5, wherein: The inner surface of the rotating bullet (3) is provided with a rotating contact surface (33) corresponding to the outer wall of the rotating shaft (6). The rotating contact surface (33) extends from the free end (32) toward the fixed end (31). The rotating bullet (3) rotates and engages with the rotating shaft (6) through the rotating contact surface (33). The rotating shaft (6) has a detached state and an assembled state relative to the shaft hole (11). When the rotating shaft (6) is in the detached state relative to the shaft hole (11), the distance between the rotating contact surfaces (33) of any two rotating bullet pieces (3) gradually decreases from the fixed end (31) toward the free end (32). When the rotating shaft (6) and the shaft hole (11) are in the assembled state, the rotating shaft (6) squeezes a number of rotating bullet pieces (3) to open radially outward, so that the number of rotating bullet pieces (3) squeeze the rotating shaft (6) radially inward, and drives the rotating shaft (6) and the shaft hole (11) to maintain or move to a concentric position.

8. A brushless motor rotor assembly having a damping structure according to claim 7, characterized in that: The end of the rotating contact surface (33) located on one side of the fixed end (31) is smoothly connected to the edge of the shaft hole (11).

9. A brushless motor rotor assembly having a cushioning structure according to claim 7, wherein: The inner wall on the side of the free end (32) of the rotor bullet (3) is provided with a guide slope (321), the rotating shaft (6) is guided and matched with the rotating abutting surface (33) through the guide slope (321), and the inclination angle a of the guide slope (321) relative to the rotating shaft (6) is 5-40°.

10. A brushless motor rotor assembly having a cushioning structure according to any one of claims 1-9, characterized in that: The upper and lower ends of the rotor shell (1) extend radially outward to form annular anti-disengagement portions (15), the annular anti-disengagement portions (15) between the two sides form a mounting groove (12) on the outer wall of the rotor shell (1), the magnet (5) is provided in an annular structure, the magnet (5) is mounted on the rotor shell (1) through the mounting groove (12), and the two ends of the magnet (5) are in anti-disengagement cooperation with the corresponding annular anti-disengagement portions (15).

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