A brushless motor rotor assembly and a brushless motor

Abstract

The utility model discloses a kind of brushless motor rotor assembly and brushless motor, it is related to motor field.The brushless motor rotor assembly includes: motor shaft, its outer side wall is protruded with multiple circumferential distribution's convex rib;Plastic dynamic balance ring is equipped with the first center hole of axial through, plastic dynamic balance ring is set on motor shaft by the first center hole;Wherein, the first center hole is formed with multiple convex rib interference fit, and with the outer side wall of motor shaft clearance fit.The brushless motor rotor assembly provided by the utility model can avoid surface damage of motor shaft during assembly process, facilitate motor noise control, while reducing cost and meeting lightweight design requirements.

Description

Technical Field

[0001] This utility model relates to the field of motors, and more specifically, to a brushless motor rotor assembly and a brushless motor. Background Technology

[0002] Currently, the brushless motors used in car seats typically employ dynamic balancing rings as the weight-reducing material in their rotor assemblies. These rings are fixed to the motor shaft by press-fitting and undergo localized mass removal during the dynamic balancing process through drilling or milling to eliminate rotor imbalance.

[0003] When the dynamic balancing ring is pressed onto the motor shaft, it is easy for the ring to scratch the outer wall of the motor shaft, especially the bearing stop at the end of the shaft. This scratch will affect the rotational accuracy of the motor, increase operating noise, and reduce its service life.

[0004] To alleviate this problem, copper, which has lower hardness, is commonly used as the material for dynamic balancing rings. While this reduces the risk of scratching the motor shaft, the material cost is too high and it is not conducive to the lightweight design requirements of the motor. Utility Model Content

[0005] The purpose of this invention is to provide a brushless motor rotor assembly that can avoid surface damage to the motor shaft during assembly, reduce costs, and meet lightweight design requirements.

[0006] Another objective of this invention is to provide a brushless motor that can avoid surface damage to the motor shaft during assembly, reduce costs, and meet lightweight design requirements.

[0007] The embodiments of this utility model provide a technical solution: A brushless motor rotor assembly, comprising: The motor shaft has multiple circumferentially distributed ribs protruding from its outer side wall; A plastic dynamic balancing ring has a first central hole that extends axially through it, and the plastic dynamic balancing ring is sleeved on the motor shaft through the first central hole; The first central hole forms an interference fit with the plurality of ribs and a clearance fit with the outer side wall of the motor shaft.

[0008] In an optional embodiment, the brushless motor rotor assembly further includes a rotor core sleeved on the motor shaft, and the plastic dynamic balance ring and the rotor core are axially arranged on the motor shaft; The rotor core is provided with a core weight reduction hole, and the plastic dynamic balance ring is provided with a boss that extends into the core weight reduction hole and forms an interference fit with the core weight reduction hole.

[0009] In an optional embodiment, the first central hole has a first chamfer at one end near the rotor core, and a first rounded corner is provided between the first chamfer and the hole wall of the first central hole.

[0010] In an optional embodiment, the rotor core is provided with a second central hole that extends axially through it, and the rotor core is sleeved on the motor shaft through the second central hole; The second central hole forms an interference fit with the plurality of the protruding ribs and a clearance fit with the outer side wall of the motor shaft.

[0011] In an optional embodiment, the number of plastic dynamic balancing rings is two, and the two plastic dynamic balancing rings are respectively located at both ends of the rotor core along the axial direction. The brushless motor rotor assembly also includes a main magnetic ring, which is sleeved on the outer wall of the rotor core and located between the two plastic dynamic balance rings.

[0012] In an optional embodiment, the brushless motor rotor assembly further includes an iron-copper-based powder metallurgy bushing and a Hall magnetic ring, wherein the iron-copper-based powder metallurgy bushing is disposed on the motor shaft and the Hall magnetic ring is sleeved on the outer side wall of the iron-copper-based powder metallurgy bushing.

[0013] In an optional embodiment, the iron-copper-based powder metallurgy bushing is provided with a third central hole that extends axially, and the iron-copper-based powder metallurgy bushing is sleeved on the motor shaft through the third central hole; The third center hole has a second chamfer at one end near the plastic dynamic balancing ring, and a second rounded corner is provided between the second chamfer and the hole wall of the third center hole.

[0014] In an optional embodiment, the iron-copper based powder metallurgy bushing forms an interference fit with the motor shaft, and / or, The Hall magnetic ring is bonded to the iron-copper based powder metallurgy bushing.

[0015] In an optional embodiment, the motor shaft includes an axially connected rib section and a smooth shaft section, with a plurality of ribs protruding from the rib section, and the iron-copper based powder metallurgy bushing sleeved on the smooth shaft section.

[0016] An embodiment of this utility model also provides a brushless motor, including the aforementioned brushless motor rotor assembly. The brushless motor rotor assembly includes: The motor shaft has multiple circumferentially distributed ribs protruding from its outer side wall; A plastic dynamic balancing ring has a first central hole that extends axially through it, and the plastic dynamic balancing ring is sleeved on the motor shaft through the first central hole; The first central hole forms an interference fit with the plurality of ribs and a clearance fit with the outer side wall of the motor shaft.

[0017] Compared to existing technologies, the brushless motor rotor assembly provided by this invention features a plastic dynamic balancing ring. Compared to commercially available copper dynamic balancing rings, this significantly reduces material costs and weight, meeting lightweight design requirements. Furthermore, the plastic dynamic balancing ring has lower hardness than a metal motor shaft. Additionally, the motor shaft has multiple circumferentially distributed ribs on its outer wall, and the plastic dynamic balancing ring is press-fitted onto these ribs while maintaining a clearance fit with the outer wall of the motor shaft. This prevents scratching the motor shaft during assembly. Therefore, the beneficial effects of the brushless motor rotor assembly provided by this invention include: preventing surface damage to the motor shaft during assembly, thus avoiding motor noise problems, while simultaneously reducing costs and meeting lightweight design requirements. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of this utility model, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this utility model and therefore should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without any creative effort.

[0019] Figure 1 A schematic diagram of the structure of the brushless motor rotor assembly provided in an embodiment of this utility model; Figure 2 An exploded view of the brushless motor rotor assembly provided for an embodiment of this utility model; Figure 3 A cross-sectional view of a brushless motor rotor assembly provided for an embodiment of this utility model; Figure 4 for Figure 2 Schematic diagram of the structure of the motor shaft; Figure 5 for Figure 2 A schematic diagram of the structure of a medium-sized plastic dynamic balancing ring from one perspective; Figure 6 for Figure 2 A schematic diagram of the structure of a medium-sized plastic dynamic balancing ring from another perspective; Figure 7 for Figure 5 Sectional view of AA; Figure 8 for Figure 2 Schematic diagram of the rotor core structure; Figure 9 for Figure 2A schematic diagram of the structure of a China Railway copper-based powder metallurgy bushing from one perspective; Figure 10 for Figure 2 A schematic diagram of the structure of China Railway's copper-based powder metallurgy bushing from another perspective; Figure 11 for Figure 2 Cross-sectional view of a copper-based powder metallurgy bushing from China Railway.

[0020] Icons: 100-Brushless motor rotor assembly; 110-Motor shaft; 111-Rib; 112-Rib segment; 113-Smooth shaft segment; 114-Bearing stop; 120-Plastic dynamic balancing ring; 121-First center hole; 122-Second weight reduction hole; 123-Boss; 124-First chamfer; 125-First rounded corner; 130-Rotor core; 131-Core weight reduction hole; 132-Second center hole; 140-Main magnetic ring; 150-Iron-copper based powder metallurgy bushing; 151-Third center hole; 152-Second chamfer; 153-Second rounded corner; 154-Stepped section; 160-Hall effect magnetic ring. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0022] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0023] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0024] In the description of this utility model, it should be understood that the terms "upper", "lower", "inner", "outer", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship that the utility model product is usually placed in during use, or the orientation or positional relationship that is commonly understood by those skilled in the art. They are only used to facilitate the description of this utility model and to simplify the description, and are not intended to indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0025] Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0026] In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, terms such as "set" and "connection" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0027] The specific embodiments of this utility model will now be described in detail with reference to the accompanying drawings.

[0028] Example Please refer to the following: Figure 1 and Figure 2 , Figure 1 The diagram shown is a structural schematic of the brushless motor rotor assembly 100 provided in this embodiment. Figure 2 The diagram shown is an exploded view of the brushless motor rotor assembly 100.

[0029] The brushless motor rotor assembly 100 provided in this embodiment includes a motor shaft 110, a plastic dynamic balancing ring 120, a rotor core 130, a main magnetic ring 140, an iron-copper based powder metallurgy bushing 150, and a Hall magnetic ring 160. The plastic dynamic balancing ring 120, the rotor core 130, and the iron-copper based powder metallurgy bushing 150 are all sleeved on the motor shaft 110, the main magnetic ring 140 is sleeved on the outer side wall of the rotor core 130, and the Hall magnetic ring 160 is sleeved on the outer side wall of the iron-copper based powder metallurgy bushing 150.

[0030] Please refer to the following: Figure 3 , Figure 3 The image shown is a cross-sectional view of the brushless motor rotor assembly 100.

[0031] In this embodiment, there are two plastic dynamic balancing rings 120, which are located at opposite ends of the rotor core 130 and cooperate with the rotor core 130 to form a combined structure. Along the axial direction of the motor shaft 110, iron-copper based powder metallurgy bushings 150 are arranged at intervals with this combined structure.

[0032] In the radial direction of the motor shaft 110, two plastic dynamic balance rings 120 protrude from the rotor core 130 and together with the outer side wall of the rotor core 130 form a circumferentially extending and end-to-end connected slot structure. The main magnetic ring 140 is located in this slot structure so that the axial displacement of the main magnetic ring 140 is constrained.

[0033] In other words, the two plastic dynamic balancing rings 120 effectively limit the axial movement of the main magnetic ring 140, preventing it from axially shifting or deviating due to vibration or centrifugal force during high-speed rotation of the motor, thereby ensuring that the main magnetic ring 140 is always in the predetermined installation position.

[0034] Furthermore, this slot structure not only improves the assembly accuracy and operational reliability of the main magnetic ring 140, but also avoids the need for additional independent retaining rings, thus simplifying the overall structure of the brushless motor rotor assembly 100 and improving assembly efficiency.

[0035] Furthermore, to enhance the reliable constraint of the main magnetic ring 140, in this embodiment, the main magnetic ring 140 is also bonded and fixed to the outer wall of the rotor core 130. Combined with two plastic dynamic balancing rings 120, the main magnetic ring 140 is subjected to dual constraints of axial limiting and circumferential anti-rotation, significantly improving the overall connection strength of the main magnetic ring 140 and further ensuring the reliability and safety of motor operation.

[0036] Please refer to the following: Figure 4 , Figure 4 The diagram shown is a structural schematic of the motor shaft 110.

[0037] In this embodiment, the motor shaft 110 includes an axially connected rib section 112 and a smooth shaft section 113. Multiple ribs 111 protrude from the outer wall of the rib section 112, and these ribs are distributed circumferentially in sequence. Two plastic dynamic balancing rings 120 and the rotor core 130 are both fitted onto the rib section 112, while the iron-copper based powder metallurgy bushing 150 is fitted onto the smooth shaft section 113.

[0038] In this embodiment, the extending direction of each rib 111 is parallel to the axial direction of the motor shaft 110, and the plurality of ribs 111 are evenly distributed in the circumferential direction of the motor shaft 110. It can be understood that the end of the rib segment 112 away from the optical shaft segment 113, and the end of the optical shaft segment 113 away from the rib segment 112, both have a bearing stop 114 for cooperating with the inner ring of the bearing.

[0039] Please refer to the following: Figure 5 , Figure 6 and Figure 7 , Figure 5 The image shown is a schematic diagram of the plastic dynamic balancing ring 120 from one perspective. Figure 6 The image shown is a schematic diagram of the plastic dynamic balancing ring 120 from another perspective. Figure 7 As shown Figure 5 Sectional view of AA.

[0040] Understandably, the plastic dynamic balance ring 120 is made of plastic. Compared to the metal motor shaft 110, the plastic dynamic balance ring 120 has lower hardness, which can prevent scratching the motor shaft 110 during assembly. Furthermore, the plastic dynamic balance ring 120 has a lighter weight, meeting the lightweight design requirements of the overall structure.

[0041] Preferably, the plastic dynamic balancing ring 120 in this embodiment is a composite engineering plastic with nylon 66 (PA66) as the matrix and 33% glass fiber reinforcement. It features high strength, high heat resistance, and lightweight properties, while also possessing excellent mechanical properties and processability. In the dynamic balancing process, it can easily and quickly complete drilling or milling operations, accurately correcting imbalances, improving the smoothness of motor operation, and reducing noise.

[0042] The plastic dynamic balancing ring 120 has an axially penetrating first central hole 121, through which the plastic dynamic balancing ring 120 is fitted onto the rib section 112 of the motor shaft 110. Furthermore, the first central hole 121 forms an interference fit with the plurality of ribs 111 and a clearance fit with the outer side wall of the motor shaft 110.

[0043] It is understandable that the first central hole 121 and the multiple ribs 111 form an interference fit to reliably fix the plastic dynamic balance ring 120 on the motor shaft 110. Furthermore, there is a gap between the hole wall of the first central hole 121 and the outer wall of the motor shaft 110, so that the two do not directly contact each other and can avoid scratching the motor shaft 110.

[0044] In other words, the first center hole 121 and the multiple ribs 111 form an interference fit, ensuring the stable installation of the plastic dynamic balance ring 120 on the motor shaft 110 and preventing relative slippage during operation. The clearance fit between the hole wall of the first center hole 121 and the outer wall of the motor shaft 110 avoids direct contact between the two during assembly and operation, effectively preventing mechanical damage to the surface of the motor shaft 110, especially in the bearing stop 114 area, reducing noise, and ensuring rotational accuracy and service life.

[0045] Please refer to the following: Figure 8 , Figure 8 The diagram shown is a schematic diagram of the rotor core 130.

[0046] It is understandable that the rotor core 130 is a cylindrical structure formed by stacking multiple silicon steel sheets. The rotor core 130 is provided with an axially penetrating second central hole 132, and the rotor core 130 is sleeved on the rib section 112 of the motor shaft 110 through the second central hole 132.

[0047] Similarly, the second central hole 132 forms an interference fit with the multiple ribs 111 and a clearance fit with the outer wall of the motor shaft 110. The interference fit between the second central hole 132 and the multiple ribs 111 ensures reliable fixation of the rotor core 130 on the motor shaft 110, guaranteeing reliable transmission. The clearance between the rotor core 130 and the outer wall of the motor shaft 110 prevents the rotor core 130 from scratching the motor shaft 110.

[0048] In other words, the second center hole 132 and the multiple ribs 111 form an interference fit, ensuring the stable installation of the rotor core 130 on the motor shaft 110 and preventing relative slippage during operation. The clearance fit between the hole wall of the second center hole 132 and the outer wall of the motor shaft 110 avoids direct contact between the two during assembly and operation, effectively preventing mechanical damage to the surface of the motor shaft 110, especially in the bearing stop 114 area, further reducing noise, and ensuring rotational accuracy and service life.

[0049] In another embodiment, in order to further improve the stable installation effect of the rotor core 130 on the motor shaft 110, multiple mating grooves can be opened on the hole wall of the second center hole 132. The multiple mating grooves are fitted into the multiple protruding ribs 111 one by one, which further improves the axial and circumferential constraint of the rotor core 130, thereby further improving the stability of the overall structure during operation.

[0050] In this embodiment, the rotor core 130 is provided with core weight reduction holes 131, which are parallel to the second central hole 132 and penetrate through the rotor core 130. Preferably, in this embodiment, there are multiple core weight reduction holes 131, which are evenly distributed around the second central hole 132. By providing multiple core weight reduction holes 131, the mass of the rotor core 130 is reduced, thereby reducing the rotational inertia of the overall structure. The evenly distributed multiple core weight reduction holes 131 help maintain the mass balance of the overall structure, reduce vibration, and lower noise.

[0051] To further improve the constraint reliability of the plastic dynamic balancing ring 120, in this embodiment, each of the two plastic dynamic balancing rings 120 has a protrusion 123 on the side near the rotor core 130. The protrusion 123 extends into the core weight reduction hole 131 and forms an interference fit with the core weight reduction hole 131 to ensure the axial and circumferential positioning of the plastic dynamic balancing ring 120.

[0052] The interference fit between the boss 123 and the weight reduction hole 131 of the iron core effectively prevents the plastic dynamic balance ring 120 from axial movement or circumferential rotation during high-speed motor operation, significantly improving its installation stability on the motor shaft 110. This avoids the risk of loosening, displacement, or even detachment due to vibration or centrifugal force, ensuring the reliability of the dynamic balance correction results. Furthermore, the tight fit structure between the plastic dynamic balance ring 120, the rotor iron core 130, and the motor shaft 110 further reduces operating vibration and noise.

[0053] The boss 123 also serves as a guide and centering element during assembly, guiding the plastic dynamic balancing ring 120 to accurately fit onto the motor shaft 110 and smoothly align with the rotor core 130, reducing assembly errors and improving the efficiency and yield of automated assembly. Furthermore, the cooperation between the boss 123 and the core weight-reducing hole 131 transfers part of the load from the plastic dynamic balancing ring 120 to the rotor core 130, helping to distribute the stress, reduce local stress concentration, and extend service life.

[0054] It is understood that the boss 123 can be integrally formed with the corresponding plastic dynamic balance ring 120 by injection molding. Preferably, in this embodiment, each of the two plastic dynamic balance rings 120 is provided with two bosses 123, and the two bosses 123 of any plastic dynamic balance ring 120 respectively form an interference fit with two different iron core weight reduction holes 131.

[0055] In another embodiment, the number of bosses 123 on the plastic dynamic balancing ring 120 can be adjusted according to actual needs. Furthermore, one boss 123 of each of the two plastic dynamic balancing rings 120 can extend into both ends of the same iron core weight reduction hole 131, or it can extend into different iron core weight reduction holes 131.

[0056] It should be noted that in this embodiment, the length of each rib 111 is greater than the sum of the axial dimensions of the rotor core 130 and the two plastic dynamic balance rings 120, and any end of each rib 111 extends beyond or is flush with the corresponding plastic dynamic balance ring 120, ensuring that the two plastic dynamic balance rings 120 can fully interfere with the multiple ribs 111, thus ensuring the axial positioning of the two plastic dynamic balance rings 120 and the rotor core 130 on the motor shaft 110.

[0057] In this embodiment, both plastic dynamic balancing rings 120 are provided with second weight-reducing holes 122, and there are two second weight-reducing holes 122. The two second weight-reducing holes 122 and the two bosses 123 are alternately and evenly arranged in the circumferential direction of the first central hole 121. In another embodiment, the number and position of the second weight-reducing holes 122 can be adjusted according to the actual application conditions.

[0058] In order to further prevent the plastic dynamic balance ring 120 from scratching the motor shaft 110 during the assembly process, in this embodiment, the first center hole 121 is provided with a first chamfer 124 at one end near the rotor core 130, and a first rounded corner 125 is provided between the first chamfer 124 and the hole wall of the first center hole 121.

[0059] The first chamfered portion 124 achieves a smooth transition with the inner wall of the first center hole 121 through the first rounded corner portion 125, effectively avoiding scratches on the surface of the motor shaft 110 during the press-fitting process due to the presence of sharp edges at the hole opening.

[0060] Specifically, during the actual assembly process, after the rotor core 130 is pressed onto the rib section 112 of the motor shaft 110, two plastic dynamic balancing rings 120 are pressed onto the rib section 112 from both ends of the motor shaft 110. When the plastic dynamic balancing rings 120 are axially fitted onto the motor shaft 110, even if there is a slight assembly misalignment or alignment error, the outer wall of the motor shaft 110 first contacts the first chamfered portion 124, rather than directly impacting the sharp-angled opening, thus avoiding surface scratches.

[0061] The presence of the first chamfered portion 124 serves as a guide, allowing the motor shaft 110 to smoothly enter the first central hole 121. Simultaneously, the continuous transition structure between the first chamfered portion 124 and the first rounded corner portion 125 eliminates sharp edges, significantly reducing the risk of localized stress concentration and frictional damage between the motor shaft 110 and the chamfered portion.

[0062] Furthermore, the structure combining the first chamfered portion 124 and the first rounded corner portion 125 not only improves the assembly yield and reduces assembly resistance, but also avoids the risk of debris being generated due to the edge of the plastic dynamic balance ring 120 hole breaking, which could then contaminate the internal environment of the motor, thereby improving assembly reliability and product quality.

[0063] Please refer to the following: Figure 9 , Figure 10 and Figure 11 , Figure 9 The image shown is a schematic diagram of the iron-copper based powder metallurgy bushing 150 from one perspective. Figure 10 The image shown is a schematic diagram of the iron-copper based powder metallurgy bushing 150 from another perspective. Figure 11 The image shown is a cross-sectional view of the iron-copper based powder metallurgy bushing 150.

[0064] In this embodiment, the iron-copper-based powder metallurgy bushing 150 is sleeved on the optical axis section 113 of the motor shaft 110 and forms an interference fit with the optical axis section 113. Specifically, the iron-copper-based powder metallurgy bushing 150 is provided with an axially penetrating third central hole 151, through which the iron-copper-based powder metallurgy bushing 150 is sleeved on the optical axis section 113 of the motor shaft 110.

[0065] It is understandable that the iron-copper based powder metallurgy bushing 150 and the optical shaft section 113 of the motor shaft 110 form an interference fit to ensure that there is no relative movement between the iron-copper based powder metallurgy bushing 150 and the motor shaft 110 during motor operation, thus ensuring the stability and reliability of the overall structure.

[0066] Furthermore, the iron-copper based powder metallurgy bushing 150 is made of iron-copper based powder metallurgy material, specifically FeCuA-10, which has a certain porosity and a hardness lower than that of the motor shaft 110. During the pressing process onto the optical shaft section 113 of the motor shaft 110, it can avoid scratching the motor shaft 110 through a small amount of self-generated plastic deformation, thereby effectively protecting the outer surface of the motor shaft 110.

[0067] Similarly, in order to further prevent the iron-copper based powder metallurgy bushing 150 from scratching the motor shaft 110 during the assembly process, in this embodiment, the third center hole 151 is provided with a second chamfer 152 near the end of the plastic dynamic balance ring 120, and a second rounded corner 153 is provided between the second chamfer 152 and the hole wall of the third center hole 151.

[0068] The second chamfered portion 152 achieves a smooth transition with the inner wall of the third center hole 151 through the second rounded corner portion 153, effectively avoiding scratches on the surface of the motor shaft 110 during the press-fitting process due to the presence of sharp edges at the hole opening.

[0069] Specifically, during the actual assembly process, the iron-copper based powder metallurgy bushing 150 is press-fitted onto the rib section 112 from the end of the smooth shaft section 113 of the motor shaft 110 away from the rib section 112. When the iron-copper based powder metallurgy bushing 150 is axially fitted into the motor shaft 110, even if there is a slight assembly misalignment or alignment error, the outer wall of the motor shaft 110 first contacts the second chamfered portion 152, rather than directly impacting the acute angle opening, thus avoiding surface scratches.

[0070] The presence of the second chamfer 152 serves as a guide, allowing the motor shaft 110 to smoothly enter the third center hole 151. Simultaneously, the continuous transition structure between the second chamfer 152 and the second rounded corner 153 eliminates sharp edges, significantly reducing the risk of localized stress concentration and frictional damage between the motor shaft 110 and the chamfer.

[0071] Furthermore, the combination of the second chamfer 152 and the second rounded corner 153 not only improves the assembly yield and reduces assembly resistance, but also avoids the risk of debris being generated due to damage to the edge of the third center hole 151, thereby contaminating the internal environment of the motor, further improving assembly reliability and product quality.

[0072] In this embodiment, a stepped portion 154 is formed on the outer wall of the iron-copper based powder metallurgy bushing 150, and a Hall magnetic ring 160 is sleeved on the stepped portion 154, so that the stepped portion 154 forms a reliable constraint on the Hall magnetic ring 160.

[0073] Preferably, in this embodiment, the Hall magnetic ring 160 is also bonded and fixed to the iron-copper-based powder metallurgy bushing 150, further improving the positioning effect of the Hall magnetic ring 160 on the iron-copper-based powder metallurgy bushing 150.

[0074] Specifically, the Hall magnetic ring 160 is bonded and fixed to the stepped surface and vertical surface of the stepped portion 154 of the iron-copper-based powder metallurgy bushing 150, respectively, thereby achieving dual constraint of the Hall magnetic ring 160 in both axial and circumferential directions, which significantly improves the structural stability after assembly.

[0075] In summary, the brushless motor rotor assembly 100 provided in this embodiment uses a plastic dynamic balancing ring 120 instead of a traditional copper dynamic balancing ring. Through the interference fit between the plastic dynamic balancing ring 120 and multiple protrusions 111 on the outer wall of the motor shaft 110, and the clearance fit between the plastic dynamic balancing ring 120 and the outer wall of the motor shaft 110, scratch protection for the motor shaft 110 is achieved. Furthermore, by providing a first chamfer 124 at the end of the first central hole 121 of the plastic dynamic balancing ring 120 near the rotor core 130, and designing a first rounded corner 125 between the first chamfer 124 and the wall of the first central hole 121, a smooth transition structure is formed, further improving assembly reliability and preventing damage to the motor shaft 110 from the edge of the hole.

[0076] Furthermore, the brushless motor rotor assembly 100 prevents the rotor core 130 from scratching the motor shaft 110 by interference fit with multiple protruding ribs 111 on the outer side wall of the motor shaft 110 and clearance fit with the outer side wall of the motor shaft 110, thereby further improving the scratch protection effect on the motor shaft 110.

[0077] In addition, the iron-copper based powder metallurgy bushing 150 is used to replace the traditional copper magnetic ring bushing. It has the characteristic of low hardness and can adapt to the shaft diameter through slight deformation during interference fitting, reducing shear force. Furthermore, the second chamfer and second fillet structure at the end of the third center hole 151 further ensure the safety of the assembly process and further improve the scratch protection effect on the motor shaft 110.

[0078] As can be seen, the brushless motor rotor assembly 100 provided in this embodiment achieves scratch protection for the motor shaft 110, and also features lightweight, low cost and better assembly effect, significantly improving the structural reliability and product quality of the brushless motor rotor assembly 100.

[0079] In addition, this embodiment also provides a brushless motor, which includes a housing, a stator assembly, and the aforementioned brushless motor rotor assembly 100. The stator assembly is disposed inside the housing, and the brushless motor assembly is disposed inside the stator assembly, and cooperates with two bearings disposed on the housing through bearing stops 114 at both ends of the motor shaft 110.

[0080] Benefiting from the advantages of the brushless motor rotor assembly 100, the brushless motor provided in this embodiment also has the characteristics of higher assembly yield, lower cost, and more stable and reliable structure.

[0081] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A brushless motor rotor assembly, characterized in that, include: The motor shaft (110) has multiple circumferentially distributed ribs (111) protruding on its outer side wall. A plastic dynamic balancing ring (120) is provided with a first central hole (121) that extends through the axis. The plastic dynamic balancing ring (120) is sleeved on the motor shaft (110) through the first central hole (121). The first central hole (121) forms an interference fit with the plurality of the protruding ribs (111) and a clearance fit with the outer side wall of the motor shaft (110).

2. The brushless motor rotor assembly according to claim 1, characterized in that, The brushless motor rotor assembly (100) also includes a rotor core (130) sleeved on the motor shaft (110), and the plastic dynamic balance ring (120) and the rotor core (130) are axially arranged on the motor shaft (110); The rotor core (130) is provided with a core weight reduction hole (131), and the plastic dynamic balance ring (120) is provided with a boss (123). The boss (123) extends into the core weight reduction hole (131) and forms an interference fit with the core weight reduction hole (131).

3. The brushless motor rotor assembly according to claim 2, characterized in that, The first central hole (121) has a first chamfer (124) at one end near the rotor core (130), and a first rounded corner (125) is provided between the first chamfer (124) and the hole wall of the first central hole (121).

4. The brushless motor rotor assembly according to claim 2, characterized in that, The rotor core (130) is provided with a second central hole (132) that extends through the axis, and the rotor core (130) is sleeved on the motor shaft (110) through the second central hole (132); The second central hole (132) forms an interference fit with the plurality of the protruding ribs (111) and a clearance fit with the outer side wall of the motor shaft (110).

5. The brushless motor rotor assembly according to claim 2, characterized in that, The number of plastic dynamic balancing rings (120) is two, and the two plastic dynamic balancing rings (120) are respectively located at the two ends of the rotor core (130) in the axial direction; The brushless motor rotor assembly (100) also includes a main magnetic ring (140), which is sleeved on the outer wall of the rotor core (130) and located between the two plastic dynamic balance rings (120).

6. The brushless motor rotor assembly according to any one of claims 1-5, characterized in that, The brushless motor rotor assembly (100) also includes an iron-copper-based powder metallurgy bushing (150) and a Hall magnetic ring (160). The iron-copper-based powder metallurgy bushing (150) is disposed on the motor shaft (110), and the Hall magnetic ring (160) is sleeved on the outer wall of the iron-copper-based powder metallurgy bushing (150).

7. The brushless motor rotor assembly according to claim 6, characterized in that, The iron-copper-based powder metallurgy bushing (150) is provided with an axially penetrating third central hole (151), and the iron-copper-based powder metallurgy bushing (150) is sleeved on the motor shaft (110) through the third central hole (151). The third center hole (151) has a second chamfer (152) at one end near the plastic dynamic balance ring (120), and a second rounded corner (153) is provided between the second chamfer (152) and the hole wall of the third center hole (151).

8. The brushless motor rotor assembly according to claim 6, characterized in that, The iron-copper based powder metallurgy bushing (150) forms an interference fit with the motor shaft (110), and / or, The Hall magnetic ring (160) is bonded to the iron-copper based powder metallurgy bushing (150).

9. The brushless motor rotor assembly according to claim 6, characterized in that, The motor shaft (110) includes an axially connected rib section (112) and a smooth shaft section (113), with a plurality of ribs (111) protruding from the rib section (112), and the iron-copper based powder metallurgy bushing (150) sleeved on the smooth shaft section (113).

10. A brushless motor, characterized in that, Includes the brushless motor rotor assembly (100) as described in any one of claims 1-9.

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