Rotor assembly of motor, motor, cleaning equipment and dynamic balance method
By placing a balance ring between the bearing and the rotor in a single-bearing motor and using a segmented structure to control the mass, the problems of excessive shaft cantilever and large bending moment are solved, thereby improving the motor's resonance critical speed and enhancing the user experience.
Patent Information
- Application Number
- CN202511812269.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-03
- Publication Date
- 2026-02-24
AI Technical Summary
In existing single-bearing motors, the balance ring and bearing are located on opposite sides of the rotor, resulting in excessively long shaft cantilever, excessive distance between the balance ring and bearing, large bending moment at the bearing end, easy deformation, and low resonance critical speed, which affects motor life and user experience.
The balance ring is placed between the bearing and the rotor, and a segmented balance ring structure is adopted. By adjusting the diameter of the second segment and performing dynamic balancing trimming or counterweighting on the first segment, the mass distribution is finely adjusted, the cantilever length and bending moment are reduced, and the resonant critical speed is increased.
It effectively increases the motor's resonance critical speed, avoids rotor resonance at low speeds, extends motor life, improves user experience, reduces costs, and simplifies assembly processes.
Smart Images
Figure CN121566841A_ABST
Abstract
Description
Technical Field
[0001] This application belongs to the field of motor technology, specifically relating to a rotor assembly of an electric motor, an electric motor, a cleaning device, and a dynamic balancing method. Background Technology
[0002] Floor scrubbers, vacuum cleaners, and other cleaning equipment use motors as a power source to generate suction airflow to clean the surface. In existing single-bearing motors, the bearing and balance ring are located on opposite sides of the rotor, with the balance ring at the tail end of the shaft. In this structure, the length of the shaft extending beyond the rotor must be greater than the axial length of the balance ring. Excessive shaft cantilever and a large distance between the balance ring and the bearing result in a large cantilever bending moment at the bearing end, making it prone to deformation during rotation. This causes the rotor's resonance critical speed to be lower than expected, making the rotor more susceptible to resonance at lower operating speeds, thus affecting motor lifespan and user experience. Summary of the Invention
[0003] The purpose of this application is to provide a rotor assembly for an electric motor, an electric motor, a cleaning device, and a dynamic balancing method to effectively increase the resonant critical speed of the electric motor, avoid resonance of the electric motor at the operating speed, and help improve the service life of the electric motor and the user experience.
[0004] To achieve the above objectives, the first aspect of this application provides a rotor assembly for an electric motor, comprising:
[0005] A rotating shaft having a first end and a second end that are positioned opposite to each other;
[0006] A bearing is sleeved on the rotating shaft and located near the first end, the bearing being used to constrain the radial movement of the rotating shaft;
[0007] The rotor is sleeved on the rotating shaft and located near the second end;
[0008] A balance ring is fitted onto the rotating shaft and located between the rotor and the bearing.
[0009] In one or more embodiments, the balance ring abuts against the rotor end face to position the rotor axially on the shaft.
[0010] In one or more embodiments, a gap is formed between the balance ring and the bearing.
[0011] In one or more embodiments, in the direction from the first end to the second end, the balancing ring includes a first segment and a second segment arranged sequentially, the first segment being configured for dynamic balancing trimming or counterweighting, and the second segment being configured to regulate the load provided by the balancing ring by changing its diameter.
[0012] In one or more embodiments, the diameter of the second segment is smaller than that of the first segment.
[0013] To achieve the above objectives, a second aspect of this application provides an electric motor, including the rotor assembly of the electric motor described in any of the above embodiments.
[0014] In one or more embodiments, it further includes:
[0015] A housing is fitted over the rotor assembly, and the housing is connected to the outer annular surface of the bearing.
[0016] A hood is installed over the outer shell, and an air duct is formed between the hood and the shell;
[0017] A moving impeller is arranged at the first end of the rotating shaft, the moving impeller is located inside the air duct, and is used to generate airflow inside the air duct;
[0018] Air guide vanes are arranged inside the air duct.
[0019] To achieve the above objectives, a third aspect of this application provides a cleaning device including the motor described in any of the above embodiments.
[0020] To achieve the above objectives, a fourth aspect of this application provides a method for dynamic balancing of an electric motor, the electric motor including the rotor assembly of the electric motor described in any of the above embodiments;
[0021] The dynamic balancing method includes:
[0022] Based on the operating speed of the motor, a preset resonant speed of the motor is determined, wherein the preset resonant speed is higher than the operating speed;
[0023] An initial vibration-speed-up test was performed on the motor to obtain the initial critical speed.
[0024] Based on the preset resonance speed and the initial critical speed, the mass of the balance ring is adjusted, and then a second vibration speed-up test is performed on the motor to determine whether the critical speed of the motor meets the preset resonance speed.
[0025] The motor is subjected to a dynamic balancing test, and the balance ring is dynamically balanced or counterweighted based on the test results.
[0026] In one or more embodiments, in the direction from the first end to the second end, the balancing ring includes a first segment and a second segment arranged sequentially; the step of adjusting the mass of the balancing ring includes:
[0027] Adjust the diameter of the second segment.
[0028] In one or more embodiments, the step of dynamically balancing or adding weight to the balance ring includes:
[0029] Perform dynamic balancing trimming or weighting on the first segment.
[0030] The advantages of this application, which differ from existing technologies, are:
[0031] In the rotor assembly of the motor of this application, the balance ring is located between the bearing and the rotor. The part of the shaft extending out of the rotor does not need to reserve space for installing the balance ring. Compared with the existing single bearing motor, it can effectively reduce the length of the shaft cantilever. At the same time, the balance ring is closer to the bearing, which reduces the bending moment at the bearing end, effectively avoids the deformation of the cantilever when the shaft rotates, increases the rotor resonance critical speed, avoids the rotor assembly from resonating at lower operating speeds, and helps to improve the service life of the motor and the user experience.
[0032] In the rotor assembly of the motor of this application, the balance ring abuts against the rotor end face, thereby positioning the rotor in the axial direction of the shaft. This allows the balance ring to replace the function of the shaft shoulder, which helps to reduce costs and assembly steps.
[0033] The rotor assembly of the motor in this application includes a first section and a second section arranged sequentially. By adjusting the diameter of the second section, the mass of the balance ring can be finely adjusted, thereby achieving fine adjustment of the resonant critical speed. By performing dynamic balancing trimming or counterweighting on the first section, dynamic imbalance problems caused by uneven mass distribution of components or assembly effects can be avoided, thereby helping to achieve fine adjustment of the balance ring mass, making the mass distribution of the rotor assembly more in line with expectations, and achieving the effect of improving the resonant critical speed.
[0034] In the rotor assembly of the motor of this application, the diameter of the first section of the balance ring is larger than that of the second section, so that the first section with a larger load is located on the side closer to the bearing, reducing the bending moment on the bearing end, further avoiding deformation of the cantilever during rotation, and helping to improve the resonant critical speed. Attached Figure Description
[0035] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0036] Figure 1 This is a cross-sectional structural schematic diagram of one embodiment of the rotor assembly of the motor of this application;
[0037] Figure 2This is a cross-sectional structural schematic diagram of another embodiment of the rotor assembly of this application;
[0038] Figure 3 This is a cross-sectional structural schematic diagram of one embodiment of the motor of this application;
[0039] Figure 4 This is a flowchart illustrating one embodiment of the dynamic balancing method for the motor described in this application.
[0040] Explanation of key figure labels:
[0041] Shaft 100; First end 101; Second end 102; Cantilever 103;
[0042] Bearing 200;
[0043] Rotor 300;
[0044] Balance ring 400; First section 401; Second section 402;
[0045] Casing 500;
[0046] 600 air cover; 601 air duct;
[0047] 700 moving impeller;
[0048] Air guide vane 800;
[0049] Stator 900. Detailed Implementation
[0050] To enable those skilled in the art to better understand the technical solutions in this disclosure, the technical solutions in the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments in this disclosure, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this disclosure.
[0051] Single-bearing motors use a single bearing to define the radial position of the shaft. Compared to dual-bearing motors, they have a more compact structure, lower cost, and are more suitable for applications requiring miniaturization, such as cleaning equipment.
[0052] However, in existing single-bearing motors, the balance ring and bearing are located on opposite sides of the rotor, with the balance ring at the tail end of the shaft. To accommodate the balance ring, the shaft cantilever is too long, and the distance between the balance ring and the bearing is too great. This results in a large bending moment at the bearing end, which makes it prone to deformation during rotation. Consequently, the rotor's resonance critical speed is lower than expected, and the rotor is more likely to resonate at lower operating speeds, affecting the motor's service life.
[0053] In particular, in cleaning equipment such as vacuum cleaners and floor scrubbers with handheld parts, resonance of the motor at operating speed can lead to high noise and equipment vibration, which seriously affects the user experience.
[0054] To address the aforementioned issues, the applicant has developed a novel rotor assembly for an electric motor. This rotor assembly effectively increases the rotor's critical resonance speed, prevents rotor resonance at operating speeds, and helps improve motor lifespan and enhance user experience.
[0055] Specifically, please refer to Figure 1 , Figure 1 This is a cross-sectional structural schematic diagram of one embodiment of the rotor assembly of the motor of this application.
[0056] like Figure 1 As shown, the rotor assembly includes a shaft 100 having a first end 101 and a second end 102 disposed opposite to each other.
[0057] A bearing 200, a rotor 300, and a balance ring 400 are fitted on the rotating shaft 100. The bearing 200 is located near the first end 101, the rotor 300 is located near the second end 102, and the balance ring 400 is located between the bearing 200 and the rotor 300.
[0058] Based on the above rotor assembly, the balance ring 400 is located between the bearing 200 and the rotor 300. The shaft 100 located between the second end 102 and the rotor 300 does not need to reserve space for installing the balance ring 400. Compared with the existing single bearing motor, the length of the cantilever 103 of the shaft 100 can be effectively reduced. The cantilever 103 refers to the part of the shaft 100 located between the second end 102 and the bearing 200.
[0059] Meanwhile, compared to existing single-bearing motors, in this embodiment, the balance ring 400 is closer to the bearing 200, effectively reducing the bending moment at the end of the bearing 200. Based on these two reasons, deformation of the cantilever 103 is effectively avoided when the shaft 100 rotates, thus increasing the resonant critical speed.
[0060] In one embodiment, the motor can be a brushless motor, and the rotor 300 can be a magnet. In other embodiments, the motor can be a brushed motor, and the rotor 300 can be a wound iron core. Both can achieve the effect of this embodiment.
[0061] In one embodiment, the balance ring 400 can be made of metal materials such as copper or aluminum. In other embodiments, the balance ring 400 can also be made of composite high-density materials, etc., all of which can achieve the effect of this embodiment.
[0062] Furthermore, in this embodiment, the balance ring 400 abuts against the end face of the rotor 300, thereby positioning the rotor 300 axially on the shaft 100. This allows the balance ring 400 to replace the function of the shaft shoulder, helping to reduce costs and assembly steps. When assembling the rotor 300, it is simply assembled to the position where it abuts against the balance ring 400, ensuring the assembly accuracy of the rotor 300.
[0063] Furthermore, in this embodiment, a gap d1 is formed between the balance ring 400 and the bearing 200 to avoid contact between the balance ring 400 and the outer ring of the bearing 200; at the same time, the gap d1 can provide a certain amount of operating space for dynamic balancing trimming or counterweighting of the balance ring 400.
[0064] Of course, in other embodiments, when the diameter of the side of the balance ring 400 facing the bearing 200 is less than or equal to the inner ring diameter of the bearing 200, the balance ring 400 can also abut against the inner ring of the bearing 200 to further improve the structural compactness and installation stability.
[0065] In the existing motor dynamic balancing process, based on the expected resonance critical speed, the mass of the balance ring 400 needs to be adjusted to obtain the expected rotor assembly mass distribution. In the above embodiments, the balance ring 400 adopts an integral structure. When adjusting the mass of the balance ring 400, since the axial length of the balance ring 400 is limited by the rotor 300 and the bearing 200, the diameter of the balance ring 400 needs to be adjusted as a whole, which is not conducive to fine-tuning the resonance critical speed.
[0066] To resolve the above issues, please refer to Figure 2 , Figure 2 This is a cross-sectional structural schematic diagram of another embodiment of the rotor assembly of this application.
[0067] like Figure 2 As shown, in this embodiment, the balance ring 400 includes a first segment 401 and a second segment 402 arranged sequentially along the direction from the first end 101 to the second end 102. The first segment 401 can be used for dynamic balancing trimming or counterweighting, and the second segment 402 can be used to adjust the load provided by the balance ring 400 by changing its diameter. That is, the mass of the balance ring 400 can be adjusted by adjusting the diameter of the second segment 402 so that the mass distribution of the rotor assembly meets the expectations.
[0068] Specifically, when conducting vibration acceleration tests, the diameter of the second segment 402 can be adjusted based on the initial critical speed obtained from the test, while the diameter of the first segment 401 and the length of the bearing 200 remain unchanged. The mass of the balance ring 400 can be finely adjusted, thereby achieving fine adjustment of the resonance critical speed.
[0069] Furthermore, after the diameter adjustment of the second segment 402 is completed, a dynamic balance test can be performed, and the first segment 401 can be dynamically balanced or counterweighted based on the unbalance obtained from the test, so as to avoid dynamic imbalance problems caused by uneven mass distribution of parts or assembly effects.
[0070] Specifically, dynamic balancing trimming can involve drilling, cutting, milling, grinding, or other operations on the first section 401 to remove some material from the first section 401 and make the rotor assembly mass distribution uniform. Counterweighting can involve welding balance pins, applying balance putty, or adding balance blocks to the first section 401 to increase the counterweight mass and make the rotor assembly mass distribution uniform.
[0071] Based on the segmented balance ring 400 structure described above, it is helpful to fine-tune the mass of the balance ring 400, so that the mass distribution of the rotor assembly is more in line with expectations, thereby improving the resonant critical speed.
[0072] Furthermore, in this embodiment, the diameter of the first segment 401 is larger than that of the second segment 402, so that the first segment 401 with a larger load is located on the side closer to the bearing 200, reducing the bending moment at the end of the bearing 200, further preventing the cantilever 103 from deforming during rotation, and helping to improve the resonant critical speed.
[0073] Of course, in other embodiments, the diameters of the first segment 401 and the second segment 402 may be the same, or the diameter of the first segment 401 may be smaller than that of the second segment 402. By adjusting the diameter of the second segment 402, the purpose of fine-tuning the mass of the balance ring 400 can also be achieved. Correspondingly, by performing dynamic balancing trimming or counterweighting on the first segment 401, dynamic imbalance problems caused by uneven mass distribution of parts or assembly effects can also be effectively avoided.
[0074] In the rotor assembly of the motor based on the above embodiments, in the first aspect, the balance ring 400 is located between the shaft 100 and the rotor 300. Compared with the rotor assembly of the existing single-bearing motor, it reduces the length of the cantilever 103 and the magnitude of the bending moment at the end of the bearing 200, effectively avoids deformation of the cantilever 103, increases the resonance critical speed, and avoids resonance of the rotor assembly at operating speeds lower than the design speed, which helps to improve the service life of the motor and the user experience.
[0075] Secondly, the balance ring 400 can abut against the rotor 300, which serves to position the rotor 300 axially on the shaft 100, realizing the function of the shaft shoulder, which helps to reduce costs and assembly steps.
[0076] Thirdly, the balance ring 400 includes a first section 401 and a second section 402 arranged sequentially. The resonant critical speed can be finely adjusted by adjusting the diameter of the second section 402, so that the mass distribution of the rotor assembly meets the expectations. The dynamic imbalance caused by uneven mass distribution of parts or assembly effects can be avoided by dynamically balancing or counterweighting the first section 401, thereby effectively improving the resonant critical speed.
[0077] This application also provides an electric motor that includes the rotor assembly of any of the above embodiments. Specifically, please refer to... Figure 3 , Figure 3 This is a cross-sectional structural schematic diagram of one embodiment of the motor of this application.
[0078] like Figure 3 As shown, the motor includes a housing 500 fitted over the rotor assembly, wherein the housing 500 is connected to the outer annular surface of the bearing 200.
[0079] The motor also includes a fan cover 600 that is installed outside the housing 500, and a duct 601 is formed between the fan cover 600 and the housing 500; a moving impeller 700 is arranged at the first end 101 of the rotating shaft 100, the moving impeller 700 is located inside the duct 601 and is used to form airflow inside the duct 601; a guide vane 800 for guiding airflow is also arranged inside the duct 601.
[0080] A stator 900 is arranged on the housing 500, and the stator 900 is located opposite the rotor 300.
[0081] In this embodiment, the motor is a brushless motor. In other embodiments, the motor can also be a brushed motor, and a commutator and brushes can be arranged on the rotating shaft 100, which can achieve the effect of this embodiment.
[0082] This application also provides a cleaning device that includes a motor according to any of the above embodiments.
[0083] In one embodiment, the cleaning equipment can specifically be a vacuum cleaner, floor scrubber, sweeper, or other equipment that uses a motor to generate negative pressure to suck up and clean dust, dirt, etc. from the surface to be cleaned, and all of these can achieve the effect of this embodiment.
[0084] This application also provides a method for dynamic balancing of an electric motor, the motor including the rotor assembly of any of the above embodiments. Please refer to... Figure 4 , Figure 4 This is a flowchart illustrating one embodiment of the dynamic balancing method for the motor described in this application.
[0085] like Figure 4 As shown, the method includes:
[0086] S100. Determine the preset resonant speed of the motor based on its operating speed.
[0087] To prevent the motor from resonating at its operating speed, a preset resonance speed can be set based on the motor's operating speed.
[0088] In one embodiment, the preset resonance speed can be higher than the operating speed so that the motor does not resonate while reaching the operating speed.
[0089] For example, when using the rotor speed of the motor at 400W, the preset resonant speed can be the rotor speed of the motor at 600W.
[0090] S200. Based on the preset resonance speed, the motor is subjected to an initial vibration speed-up test to obtain the initial critical speed.
[0091] After determining the preset resonance speed, an initial vibration acceleration test can be performed on the motor to determine whether the motor's resonance critical speed meets the preset resonance speed and to obtain the motor's initial critical speed.
[0092] S300: Based on the preset resonance speed and initial critical speed, the mass of the balance ring is adjusted, and then a secondary vibration speed-up test is performed on the motor to determine whether the critical speed of the motor meets the preset resonance speed.
[0093] Based on the initial critical speed and preset resonance speed obtained from the initial vibration acceleration test, the mass of the balance ring can be adjusted so that the motor's resonance critical speed is close to the preset resonance speed.
[0094] Specifically, in one embodiment, the balancing ring includes a first segment and a second segment arranged sequentially in the direction from the first end of the rotating shaft to the second end; the method for adjusting the mass of the balancing ring may specifically be: adjusting the diameter of the second segment.
[0095] By adjusting the diameter of one segment of the balancing ring, the mass of the balancing ring can be fine-tuned, which helps to achieve the desired mass distribution.
[0096] After the balance ring's mass adjustment is completed, a secondary vibration acceleration test can be conducted to ensure that the motor's critical speed meets the preset resonance speed.
[0097] Among them, the critical speed of the motor satisfies the preset resonance speed, which means that the absolute value of the difference between the critical speed of the motor and the preset resonance speed is less than the threshold.
[0098] S400: Perform dynamic balancing tests on the motor, and based on the test results, perform dynamic balancing trimming or weighting on the balance ring.
[0099] After the critical speed of the motor meets the preset resonance speed, a dynamic balance test can be performed on the motor. Based on the dynamic imbalance obtained from the test, the balance ring can be dynamically balanced or counterweighted to solve the dynamic imbalance problem caused by uneven mass distribution of parts or assembly effects.
[0100] In one embodiment, the balance ring includes a first segment and a second segment arranged sequentially in the direction from the first end to the second end of the rotating shaft; the method for dynamically balancing or balancing the balance ring can be specifically as follows:
[0101] Perform dynamic balancing trimming or weighting on the first section.
[0102] The dynamic balancing trimming can specifically involve drilling, cutting, milling, grinding, or other operations on the first section to remove some of the material from the first section and make the rotor mass distribution uniform. The counterweight can specifically involve welding balance pins, applying balance putty, or adding balance blocks to the first section to increase the counterweight mass and make the rotor mass distribution uniform.
[0103] By dynamically balancing or adding weight to a section of the balance ring, it is possible to achieve precise weight removal or addition, thereby ensuring overall dynamic balance.
[0104] It will be apparent to those skilled in the art that this disclosure is not limited to the details of the exemplary embodiments described above, and that this disclosure can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of this disclosure is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within this disclosure. No reference numerals in the claims should be construed as limiting the scope of the claims.
[0105] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.
Claims
1. A rotor assembly for an electric motor, characterized in that, include: A rotating shaft having a first end and a second end that are positioned opposite to each other; A bearing is sleeved on the rotating shaft and located near the first end, the bearing being used to constrain the radial movement of the rotating shaft; The rotor is sleeved on the rotating shaft and located near the second end; A balance ring is fitted onto the rotating shaft and located between the rotor and the bearing.
2. The rotor assembly of the motor according to claim 1, characterized in that, The balance ring abuts against the end face of the rotor to position the rotor axially on the shaft.
3. The rotor assembly of the motor according to claim 1, characterized in that, A gap is formed between the balance ring and the bearing.
4. The rotor assembly of the motor according to claim 1, characterized in that, In the direction from the first end to the second end, the balancing ring includes a first segment and a second segment arranged sequentially, the first segment being configured for dynamic balancing trimming or counterweighting, and the second segment being configured to adjust the load provided by the balancing ring by changing its diameter.
5. The rotor assembly of the motor according to claim 4, characterized in that, The diameter of the second segment is smaller than that of the first segment.
6. An electric motor, characterized in that, Includes the rotor assembly of the motor as described in any one of claims 1 to 5.
7. The motor according to claim 6, characterized in that, Also includes: A housing is fitted over the rotor assembly, and the housing is connected to the outer annular surface of the bearing. A hood is installed over the outer shell, and an air duct is formed between the hood and the shell; A moving impeller is arranged at the first end of the rotating shaft, the moving impeller is located inside the air duct, and is used to generate airflow inside the air duct; Air guide vanes are arranged inside the air duct.
8. A cleaning device, characterized in that, Includes the motor described in claim 6 or 7.
9. A method for dynamic balancing of an electric motor, characterized in that, The motor includes the rotor assembly of the motor according to any one of claims 1 to 5; The dynamic balancing method includes: Based on the operating speed of the motor, a preset resonant speed of the motor is determined, wherein the preset resonant speed is higher than the operating speed; An initial vibration-speed-up test was performed on the motor to obtain the initial critical speed. Based on the preset resonance speed and the initial critical speed, the mass of the balance ring is adjusted, and then a second vibration speed-up test is performed on the motor to determine whether the critical speed of the motor meets the preset resonance speed. The motor is subjected to a dynamic balancing test, and the balance ring is dynamically balanced or counterweighted based on the test results.
10. The dynamic balancing method according to claim 9, characterized in that, In the direction from the first end to the second end, the balancing ring includes a first segment and a second segment arranged sequentially. The steps for adjusting the mass of the balance ring include: Adjust the diameter of the second segment; and / or, The steps of dynamically balancing or adding weight to the balance ring include: Perform dynamic balancing trimming or weighting on the first segment.