Noise reduction brushless motor and method of manufacturing the same

Abstract

The application relates to the technical field of automobile part processing, in particular to a noise-reducing brushless motor and a preparation method thereof, which comprises a brushless motor body, the brushless motor body comprises a rotor, the rotor is connected with a rotor shaft, a noise-reducing structure is arranged between the rotor and the rotor shaft, the noise-reducing structure comprises a lubricating layer arranged between the rotor and the rotor shaft, a small amount of lubricating grease is applied between the brushless motor rotor and the rotor shaft, and the noise generated due to the friction and vibration between the rotor and the rotor shaft during motor operation can be effectively reduced.

Description

Technical Field

[0001] This invention relates to the field of automotive parts processing technology, and in particular to a noise-reducing brushless motor and its manufacturing method. Background Technology

[0002] Brushless motors are one of the main drive sources for automotive actuators. They are small in size, easy to install, and easy to manufacture.

[0003] Because brushless motors operate at high speeds, they are prone to generating noise during use. Traditional methods for reducing brushless motor noise mainly focus on optimizing the motor's structure, improving electromagnetic design, and adopting advanced control strategies. While these traditional methods can reduce noise to some extent, they are often costly and have low yield rates, necessitating further exploration of more effective noise reduction measures.

[0004] At the connection between the rotor and rotor shaft of a brushless motor, the relative rotation between the two can generate additional vibration and noise due to factors such as contact friction and fit precision. Current research on rotor-rotor shaft connections focuses primarily on improving transmission efficiency and ensuring axial and radial stability, with little consideration given to reducing noise at this point through simple and effective lubrication methods. Therefore, taking measures to improve motor noise in this delicate area has significant research value and practical implications. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a noise-reducing brushless motor that can effectively reduce noise.

[0006] The present invention is achieved through the following technical solution: a noise-reducing brushless motor, including a brushless motor body, the brushless motor body including a rotor, the rotor being connected to a rotor shaft, a noise-reducing structure being provided between the rotor and the rotor shaft, the noise-reducing structure including a lubrication layer provided between the rotor and the rotor shaft.

[0007] The lubricating layer is formed of grease.

[0008] Furthermore, the thickness of the lubricating layer is 0.02-0.04 mm.

[0009] Furthermore, the noise reduction structure also includes a grease storage device between the rotor and the rotor shaft, the grease storage device including a storage cavity disposed on the rotor.

[0010] Furthermore, the storage cavity includes an upper storage cavity and a lower storage cavity disposed on the rotor, both of which are annular storage cavities.

[0011] Furthermore, the outer diameter of the upper storage cavity is 0.05-0.08 mm larger than the inner diameter of the rotor, and the outer diameter of the lower storage cavity is 0.05-0.08 mm larger than the inner diameter of the rotor.

[0012] Furthermore, the length of the upper storage cavity is 2.5-4 mm, and the length of the lower storage cavity is 5-7 mm.

[0013] A method for manufacturing a noise-reducing brushless motor includes the following steps: Step 1: Fix the stator of the brushless motor and clean the rotor shaft. Use a clean cloth or cotton swab dipped in an appropriate amount of cleaning agent such as alcohol to carefully wipe the connecting surface of the rotor shaft to remove any dust, oil or other impurities that may be present, so as to ensure that the grease can work evenly. Step 2: Apply grease to the upper end of the rotor shaft, and then install the rotor. As the rotor slides down the rotor shaft, the grease is squeezed and dispersed. Step 3: Testing, test under no-load conditions.

[0014] The beneficial effect of this invention is that by applying a small amount of lubricating grease between the rotor and the rotor shaft of the brushless motor, the noise generated by friction and vibration between the rotor and the rotor shaft during motor operation can be effectively reduced. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the rotor installation location; Figure 2 This is a schematic diagram showing the connection between the rotor and the rotor shaft; Figure 3 This is a schematic diagram of the rotor cross-section.

[0016] The components are: 1. Motor body; 2. Rotor; 3. Rotor shaft; 4. Upper storage chamber; 5. Lower storage chamber. Detailed Implementation

[0017] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] In the following embodiments, The method for manufacturing a noise-reducing brushless motor includes the following steps: Step 1: Fix the stator of the brushless motor and clean the rotor shaft. Use a clean cloth or cotton swab dipped in an appropriate amount of cleaning agent such as alcohol to carefully wipe the connecting surface of the rotor shaft to remove any dust, oil or other impurities that may be present, so as to ensure that the grease can work evenly. Step 2: Apply grease to the upper end of the rotor shaft, and then install the rotor. As the rotor slides down the rotor shaft, the grease is squeezed and dispersed. Step 3: Testing, test under no-load conditions.

[0020] The noise-reducing brushless motor is a brushless motor used in small temperature control valves for automotive thermal management, such as... Figure 1-2 As shown, the device includes a brushless motor body, which includes a rotor connected to a rotor shaft. The rotor rotates at 6500 rpm, has an outer diameter of 2.55 mm, a length of 41.7 mm, and a clearance of 0.04-0.08 mm between the rotor shaft and the rotor.

[0021] There is a noise reduction structure between the rotor and the rotor shaft. The noise reduction structure includes a lubrication layer distributed between the rotor and the rotor shaft. The lubrication layer is formed by grease and has a thickness of 0.02-0.04 mm.

[0022] Lubricating grease can be selected. Klübertemp GRM07 long-lasting perfluoropolyether grease has a temperature range of -65°C to 180°C and a kinematic viscosity of approximately 2000 cst at -40°C. Klübersynth LE44-31 low-friction worm gear grease has a temperature range of -50℃ to 130℃, and a kinematic viscosity of approximately 4200 cSt at -40℃. Shell Ensis 32 rust preventative oil has a temperature range of -25℃ to 120℃, and a kinematic viscosity of approximately 6800 cSt at -40℃.

[0023] The noise reduction structure also includes a grease storage device between the rotor and the rotor shaft. The grease storage device includes a storage cavity machined on the rotor. The storage cavity includes an upper storage cavity and a lower storage cavity. Both the upper and lower storage cavities are annular. The outer diameter of the upper storage cavity is 0.05-0.08 mm larger than the inner diameter of the rotor, specifically 0.5 mm. The outer diameter of the lower storage cavity is 0.05-0.08 mm larger than the inner diameter of the rotor, specifically 0.6 mm. The length of the upper storage cavity is 2.5-4 mm, specifically 3 mm. The length of the lower storage cavity is 5-7 mm, specifically 6 mm.

[0024] Example 1 A noise-reducing brushless motor uses Klübertemp GRM07 long-lasting perfluoropolyether grease as the lubricant, with an application amount of 0.1g.

[0025] Example 2 A noise-reducing brushless motor uses Klübertemp GRM07 long-lasting perfluoropolyether grease as the lubricant, with an application amount of 0.2g.

[0026] Example 3 A noise-reducing brushless motor uses Klübertemp GRM07 long-lasting perfluoropolyether grease as the lubricant, with an application amount of 0.3g.

[0027] Example 4 A noise-reducing brushless motor uses Klübertemp GRM07 long-lasting perfluoropolyether grease as the lubricant, with an application amount of 0.4g.

[0028] Example 5 A noise-reducing brushless motor uses Klübertemp GRM07 long-lasting perfluoropolyether grease as the lubricant, with an application amount of 0.5g.

[0029] Example 6 A noise-reducing brushless motor uses Klübertemp GRM07 long-lasting perfluoropolyether grease as the lubricant, with an application amount of 0.6g.

[0030] Example 7 A noise-reducing brushless motor uses Klübersynth LE44-31 low-friction worm gear grease, with an application rate of 0.1g.

[0031] Example 8 A noise-reducing brushless motor uses Klübersynth LE44-31 low-friction worm gear grease, with an application rate of 0.2g.

[0032] Example 9 A noise-reducing brushless motor uses Klübersynth LE44-31 low-friction worm gear grease, with an application rate of 0.3g.

[0033] Example 10 A noise-reducing brushless motor uses Klübersynth LE44-31 low-friction worm gear grease, with an application rate of 0.4g.

[0034] Example 11 A noise-reducing brushless motor uses Klübersynth LE44-31 low-friction worm gear grease, with an application rate of 0.5g.

[0035] Example 12 A noise-reducing brushless motor uses Klübersynth LE44-31 low-friction worm gear grease, with an application rate of 0.6g.

[0036] Example 13 A noise-reducing brushless motor uses Shell Ensis 32 rust-preventive grease as the lubricant, with an application rate of 0.1g.

[0037] Example 14 A noise-reducing brushless motor uses Shell Ensis 32 rust-preventive grease, with an application rate of 0.2g.

[0038] Example 15 A noise-reducing brushless motor uses Shell Ensis 32 rust-preventive grease as the lubricant, with an application rate of 0.3g.

[0039] Example 16 A noise-reducing brushless motor uses Shell Ensis 32 rust-preventive grease, with an application rate of 0.4g.

[0040] Example 17 A noise-reducing brushless motor uses Shell Ensis 32 rust-preventive grease as the lubricant, with an application rate of 0.5g.

[0041] Example 18 A noise-reducing brushless motor uses Shell Ensis 32 rust-preventive grease, with an application rate of 0.6g.

[0042] Comparative Example 1 A noise-reducing brushless motor that requires no lubricant.

[0043] Comparative Example 2 A noise-reducing brushless motor uses Klübertemp GRM07 long-lasting perfluoropolyether grease as the lubricant, with an application amount of 0.3g and no upper reservoir.

[0044] Comparative Example 3 A noise-reducing brushless motor uses Klübertemp GRM07 long-lasting perfluoropolyether grease as the lubricant, with an application amount of 0.3g and no lower reservoir.

[0045] Comparative Example 4 A noise-reducing brushless motor uses Klübertemp GRM07 long-lasting perfluoropolyether grease as the lubricant, with an application amount of 0.3g, and has no upper or lower reservoir.

[0046] The test results of the noise-reducing brushless motors obtained in the above embodiments are shown in Appendix 1. In Appendix 1, three samples were sampled for each embodiment and comparative example, namely Sample 1, Sample 2 and Sample 3. The tests were conducted under no-load conditions and after running for 30 minutes.

[0047] Appendix 1

[0048] As shown in Appendix 1, the noise level of Comparative Example 1 without grease was 54-55 dB; the noise level decreased significantly after applying grease; Klübertemp GRM07 long-lasting perfluoropolyether grease showed the best noise reduction effect in the 0.2-0.4 g range, with a noise level of 42-43 dB(A) at 0.3 g, representing a noise reduction of 12-13 dB; after adding grease, the motor operating current remained at 200-220 mA, and the motor operated stably; the noise reduction improvement was limited after the grease addition exceeded 0.4 g.

[0049] Comparing Example 3 and Comparative Examples 2-4, it can be seen that the storage cavity structure has a significant impact on the noise reduction effect. Without the upper or lower storage cavity, the grease storage capacity decreases, and the noise level increases by 3-5 dB compared to Example 3. When both upper and lower storage cavities are absent, the grease is easily detached and lost due to centrifugal force, resulting in noise levels of 50-51 dB, a significant decrease in noise reduction effect, and a further increase in low-temperature operating current. This demonstrates that the grease storage device composed of an upper and lower storage cavity can effectively retain the grease and ensure long-term noise reduction performance.

[0050] Furthermore, in existing conventional brushless rotor structure designs, even knowing that the BLDC rotor needs to rotate relative to the rotor shaft to transmit power and that there must be a clearance between the two, manufacturers still generally adhere to the design approach of "no lubrication, surface strengthening" or "adding mechanical damping structure". Even if the clearance changes slightly due to alternating high and low temperatures, thermal expansion and contraction of materials, and alternating load impact, which intensifies rotational friction and wear, the conventional improvement methods in this field are limited to hard surface strengthening treatment, such as hard chrome plating of the rotor shaft, phosphating hardening of metal parts, and modification of plastic substrate to enhance wear resistance. These methods rely on increasing the hardness of the material to resist wear, and generally reject and avoid design schemes that apply grease.

[0051] Although those skilled in the art generally know that the BLDC rotor gear and rotor shaft are coaxially assembled, inherently have a clearance, and can rotate relative to each other to transmit power, and that conventional methods for controlling the friction between the two and reducing rotational wear include applying grease to reduce friction and noise, prior to the filing of this application, the industry had long deliberately abandoned and not adopted the grease application solution, for the following reasons: 1. It is necessary to select the right grease: The clearance between the miniature BLDC rotor gear and the rotor shaft is extremely small, while conventional grease has a high base viscosity and poor low-temperature fluidity. At temperatures of -25°C and below, the current increases or even the rotor stalls, which directly leads to power transmission failure and the inability of the electronic water valve core to operate. 2. Requires an oil storage structure: The product is a fixed structure with the rotor shaft (central shaft) and housing by injection molding. It is not possible to add auxiliary anti-leakage structures such as sealing rings at both ends and oil storage sealing grooves. When the BLDC rotor gear rotates at high speed, the centrifugal force will throw the conventional grease out from the mating gap. The problem of oil storage in the structure needs to be solved.

[0052] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A noise-reducing brushless motor, comprising a brushless motor body, wherein the brushless motor body includes a rotor, and the rotor is connected to a rotor shaft, characterized in that, A noise reduction structure is provided between the rotor and the rotor shaft, and the noise reduction structure includes a lubrication layer disposed between the rotor and the rotor shaft.

2. The noise-reducing brushless motor according to claim 1, characterized in that, The lubricating layer is formed of grease.

3. The noise-reducing brushless motor according to claim 2, characterized in that, The thickness of the lubricating layer is 0.02-0.04 mm.

4. The noise-reducing brushless motor according to claim 2, characterized in that, The noise reduction structure also includes a grease storage device between the rotor and the rotor shaft, the grease storage device including a storage cavity disposed on the rotor.

5. The noise-reducing brushless motor according to claim 2, characterized in that, The storage cavity includes an upper storage cavity and a lower storage cavity disposed on the rotor, and both the upper and lower storage cavities are annular storage cavities.

6. The noise-reducing brushless motor according to claim 5, characterized in that, The outer diameter of the upper storage cavity is 0.05-0.08 mm greater than the inner diameter of the rotor, and the outer diameter of the lower storage cavity is 0.05-0.08 mm greater than the inner diameter of the rotor.

7. The noise-reducing brushless motor according to claim 6, characterized in that, The length of the upper storage cavity is 2.5-4 mm, and the length of the lower storage cavity is 5-7 mm.

8. A method for manufacturing the noise-reducing brushless motor according to claim 1, comprising the following steps: Step 1: Fix the stator of the brushless motor and clean the rotor shaft. Use a clean cloth or cotton swab dipped in an appropriate amount of cleaning agent such as alcohol to carefully wipe the connecting surface of the rotor shaft to remove any dust, oil or other impurities that may be present, so as to ensure that the grease can work evenly. Step 2: Apply grease to the upper end of the rotor shaft, and then install the rotor. As the rotor slides downward along the rotor shaft, the grease is squeezed and dispersed. Step 3: Testing, test under no-load conditions.

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