Low-noise air blower system of automobile air conditioner

Abstract

The invention relates to the technical field of automobile air conditioner blowers, and discloses a low-noise automobile air conditioner blower system which comprises a wind wheel, a blower base and a motor assembly. The wind wheel is mounted on the rotor component in an inserting manner; the air blower base is connected with the motor rear end cover through screws, and an annular vibration reduction gasket made of vibration reduction rubber is added to an interface to form flexible connection. An annular vibration reduction ring made of the same material is arranged between the base and the carbon brush holder and used for weakening transmission of start-stop transient vibration. The center line of the motor carbon brush is offset relative to the rotation center axis, so that the stress direction of the carbon brush is consistent with the rotation direction when the rotor rotates clockwise, and the knocking noise of the carbon brush is reduced. The rotor adopts a skewed slot lamination structure, and air gap magnetic field distribution is improved through skewed slots which are inclined along the axial direction. The noise of the air blower is controlled in all directions, and the noise reduction effect of the whole air blower is achieved.

Description

Technical Field

[0001] This invention relates to the field of automotive air conditioning blower technology, and more specifically, to a low-noise automotive air conditioning blower system. Background Technology

[0002] Advances in modern automobile manufacturing processes have effectively suppressed traditional noise sources, but have inadvertently amplified the noise of the previously masked air conditioning blower system. This phenomenon is particularly pronounced when the vehicle is stationary or traveling at low speeds—the quieter the vehicle, the more noticeable the blower noise. Existing research largely focuses on high-speed driving conditions, neglecting the changes in noise characteristics under frequent start-stop conditions in urban traffic. When a vehicle is traveling at low speeds of 0-30 km / h or completely stationary, engine noise decreases significantly (electric vehicles approach ambient noise levels), making the blower the sole, continuously operating primary noise source. At this time, to maintain a comfortable temperature inside the vehicle, the blower typically operates under high load, with its speed increasing by 15-25%, and the noise spectrum shifts to higher frequencies. Due to the lack of masking effects from other noise sources during driving, the human ear's sensitivity to blower noise increases by approximately 8-10 dB. Human physiological studies have shown that when the vehicle is stationary, the human body's perception threshold for low-frequency vibrations (20-200 Hz) decreases by approximately 30%, because vehicle vibrations during driving can partially mask blower vibrations, but this masking effect disappears when the vehicle is stationary. When the background noise inside the vehicle is below 35 dB(A) (common in electric vehicles), the human ear becomes 40% more sensitive to noise in the 500 Hz-2 kHz frequency band, which happens to be the main distribution area of ​​the cogging harmonic noise of the blower motor.

[0003] Existing technologies primarily address steady-state operating conditions, neglecting the dynamic noise characteristics caused by frequent start-stop cycles in urban traffic. During start-stop operations, the blower undergoes a rapid acceleration-deceleration-re-acceleration cycle, generating complex transient electromagnetic and mechanical impact noise, with peak sound pressure levels 12-15 dB(A) higher than in steady-state conditions. Traditional rigid connection structures cannot effectively attenuate these transient vibrations, resulting in a "noise amplifier" effect. At the moment of motor start-stop, the carbon brushes vibrate violently due to inertia, striking the brush holder wall and producing a sharp clicking sound, which is extremely unpleasant to the touch.

[0004] Therefore, it is necessary to design a low-noise automotive air conditioning blower system to solve the problems existing in the current technology. Summary of the Invention

[0005] In view of this, the present invention proposes a low-noise automotive air conditioning blower system, which aims to solve the problem of the inability to eliminate the complex transient electromagnetic noise and mechanical impact noise of the blower.

[0006] This invention proposes a low-noise automotive air conditioning blower system, including a fan wheel, a blower base, and a motor; the motor includes a stator assembly, a rotor assembly, a front end cover, a rear end cover, a carbon brush holder, bearings, and carbon brushes; The wind turbine is fixedly installed on the rotor component by a plug-in connection; The blower base and the rear end cover of the motor are rigidly connected by screws, and an annular vibration damping washer is provided at the connection interface. The annular vibration damping washer is made of vibration damping rubber and is configured to form a flexible connection interface between the blower base and the rear end cover of the motor. An annular vibration damping ring is provided between the blower base and the carbon brush holder of the motor. The annular vibration damping ring is made of vibration damping rubber of the same material as the vibration damping washer and is configured to form a flexible connection interface between the carbon brush holder and the blower base. The carbon brush centerline of the motor is offset relative to the motor rotation center axis, and the offset direction is configured such that when the rotor rotates clockwise, the direction of force on the carbon brush is consistent with the direction of rotation. The rotor component adopts a skewed lamination structure, wherein the rotor skewers are inclined along the direction of the motor axis, and the inclination angle is used to uniformly distribute the air gap magnetic field between the stator and the rotor.

[0007] Furthermore, the annular vibration damping washer is made of vibration damping rubber with a Shore hardness of 50A to 60A and an elastic modulus of 0.25 to 0.3; the cross-section of the annular vibration damping washer has a trapezoidal concave structure, with the outer diameter being larger than the inner diameter, forming an inward pre-compression force, and maintaining effective contact during the vibration of the motor operation.

[0008] Furthermore, the annular damping ring is made of damping rubber with a Shore hardness of 50A to 60A and an elastic modulus of 0.25 to 0.3 MPa; the cross-section of the annular damping ring is concave; the inner surface of the annular damping ring is provided with a continuous annular groove, which is connected to the carbon brush holder.

[0009] Furthermore, there are two carbon brushes, which are mounted on the carbon brush holder via a carbon brush box. The center lines of the two carbon brushes are offset relative to the rotation center axis of the motor along the clockwise rotation direction of the offset rotor. One end of each carbon brush is located inside the carbon brush box and is connected to the carbon brush box by a spring.

[0010] Furthermore, the inner wall of the carbon brush box is provided with a guide structure, which forms a sliding fit with the outer surface of the carbon brush; one end of the spring contacts the tail of the carbon brush, and the other end is connected to the spring mounting structure at the bottom of the carbon brush box. The spring extends along the direction of carbon brush movement, so that the carbon brush only keeps in contact with one side of the inner wall of the carbon brush box during operation.

[0011] Furthermore, the stator component consists of a motor housing and magnets; the rotor component includes rotor skew slots, skew slot lamination structure, enameled wire, rotor shaft, positioning ring, and commutator; the rotor component is disposed inside the stator component.

[0012] Furthermore, the skew slot lamination structure of the rotor component is distributed in a right-hand spiral inclined distribution along the motor axis, and the inclination angle of each rotor skew slot remains consistent.

[0013] Furthermore, the wind turbine is fixedly installed on the rotor shaft by means of the positioning ring; the blades of the wind turbine adopt a backward-curved design, with the leading edge of the blade being arc-shaped and the trailing edge being straight.

[0014] Furthermore, the bearing includes a first bearing and a second bearing, which are respectively sleeved on the upper and lower ends of the rotor shaft, with their inner sides attached to the rotor shaft and connected to it; the outer side of the first bearing is attached to the rear end cover, and the outer side of the second bearing is attached to the front end cover.

[0015] Furthermore, the annular damping ring prevents the motor housing from directly contacting the rear end cover; the motor housing and the rear end cover are connected by the annular damping ring; the motor housing and the rear end cover are respectively located on the upper and lower sides of the annular damping ring.

[0016] Compared with existing technologies, the advantages of this invention are as follows: An annular vibration damping washer is installed between the blower base and the motor rear end cover, forming a flexible connection interface that blocks the transmission path of vibration from the motor rear end cover to the base. This damping washer is made of vibration damping rubber, with a Shore hardness of 50A-60A and an elastic modulus of 0.25-0.3. It is specifically optimized for brush wear noise in the 1kHz-10kHz frequency band, reducing noise in this band by 15-20dB(A) and improving high-frequency noise issues. An annular vibration damping ring is installed between the blower base and the motor brush holder. This ring and the damping washer are made of the same material, but the structural design is optimized for the vibration characteristics of the brush holder. By setting a continuous annular groove on the inner surface of the damping ring, the stability of the fit with the brush holder is enhanced, absorbing the mechanical noise generated by the friction between the brush and the commutator, as well as the high-frequency electromagnetic noise from electrical switching, reducing the contribution of brush holder vibration to the overall system noise. An asymmetrical axis brush design is adopted, so that the brush centerline is offset relative to the motor rotation center axis. When the rotor rotates clockwise, the carbon brush experiences force in the same direction as the rotation, ensuring stable contact between the brush and one side of the brush holder's inner wall during operation. This avoids the phenomenon of the brush swaying and impacting the holder wall, as seen in traditional designs. This design eliminates the mechanical noise generated by brush swaying. The guide structure on the inner wall of the brush holder and the sliding contact with the outer surface of the brush ensure that the brush only contacts one side of the inner wall during operation, improving noise reduction. The rotor employs a skewed slot lamination structure, with the rotor slots angled along the motor axis. The optimized angle homogenizes the air gap magnetic field distribution between the stator and rotor, eliminating cogging harmonics caused by the rotor slots. Specifically, it suppresses perceptible harmonic noise in the 500Hz–2kHz frequency band, reducing noise in this frequency range and improving the acoustic environment quality inside the vehicle. Through the synergistic effect of these four technologies, comprehensive control of blower noise is achieved, not only solving the problem of a single noise source but also eliminating the root cause of noise generation through systematic design. The offset design of the carbon brush centerline reduces contact wear between the carbon brush and the commutator, extends the service life of the carbon brush, and improves system reliability. Attached Figure Description

[0017] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 This is a front view of a low-noise automotive air conditioning blower system provided in an embodiment of the present invention; Figure 2 A cross-sectional view at point A of the low-noise automotive air conditioning blower system provided in an embodiment of the present invention; Figure 3 A schematic diagram of the structure of a low-noise automotive air conditioning blower system provided in an embodiment of the present invention. Figure 1 ; Figure 4 A schematic diagram of the structure of a low-noise automotive air conditioning blower system provided in an embodiment of the present invention. Figure 2 ; Figure 5 An enlarged view of point B in the low-noise automotive air conditioning blower system provided in an embodiment of the present invention; Figure 6 A schematic diagram of the carbon brush holder for a low-noise automotive air conditioning blower system provided in an embodiment of the present invention; Figure 7 A schematic diagram of the rotor component of a low-noise automotive air conditioning blower system provided in an embodiment of the present invention.

[0018] The components include: 1. impeller; 2. blower base; 3. motor; 311. motor housing; 312. magnet; 321. rotor skew slot; 322. skew slot laminated structure; 323. enameled wire; 324. rotor shaft; 325. positioning retaining ring; 326. commutator; 33. front cover; 34. rear cover; 35. carbon brush holder; 351. carbon brush box; 352. carbon brush; 353. spring; 361. first bearing; 362. second bearing; 4. screw; 5. annular vibration damping washer; 6. annular vibration damping ring. Detailed Implementation

[0019] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the disclosure to those skilled in the art. It should be noted that, unless otherwise specified, embodiments and features in the embodiments of the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0020] Existing automotive air conditioning blower systems are mostly designed for noise reduction under steady-state conditions, making it difficult to adapt to the dynamic noise changes caused by frequent start-stop cycles and low-speed driving in urban environments. When the vehicle is at low speed or even stationary, engine and road noise decrease significantly, making the blower the dominant noise source inside the vehicle. Current technology does not consider the increased sensitivity of the human ear to mid-to-high frequency noise after the noise masking effect disappears, resulting in prominent blower noise in actual use. Furthermore, existing blower structures generally use rigid connections, making it difficult to attenuate transient electromagnetic noise and mechanical shock vibrations caused by motor acceleration, deceleration, and speed fluctuations during start-stop cycles, significantly increasing peak sound pressure levels. In addition, traditional carbon brush mechanisms are prone to collision noise with the brush holder due to inertial oscillation during start-stop cycles, further exacerbating noise discomfort. Therefore, existing blower systems are unable to meet the low-noise comfort requirements of next-generation vehicles.

[0021] Taking a mainstream electric vehicle model as an example, when the vehicle is waiting for the exit in an underground parking garage and the speed is maintained at 0–10 km / h, the background noise in the cabin is stable at 32–34 dB(A). To maintain the air conditioning cooling effect, the blower automatically increases to about 3200 r / min, which is about 20% higher than under driving conditions. In this state, the blower exhibits obvious harmonic peaks in the 800–1600 Hz range, increasing the perceived noise by nearly 9 dB(A). At the same time, as the vehicle moves slowly in a queue, each release of the brakes triggers a slight fluctuation in the speed of the blower motor, resulting in a "whistling" transient spike in electromagnetic noise, with the sound pressure level reaching 47–50 dB(A) instantaneously, which is about 13 dB(A) higher than under steady-state conditions. More noticeably, during repeated starts and stops of the vehicle, the motor carbon brushes oscillate due to inertia and make short impacts with the brush holder, producing a clear "clicking" sound that passengers inside the vehicle can hear at a frequency of about 1–3 Hz, which is extremely subjectively disturbing. This example demonstrates that existing blower systems are significantly inadequate in noise control under stationary and low-speed road conditions, failing to meet the demand for low-noise air conditioning systems in the high-quiet environment of electric vehicles.

[0022] If the aforementioned problems remain unresolved for an extended period, they will directly lead to a significant decrease in the acoustic comfort of the vehicle interior under stationary and low-speed driving conditions. Passengers will be continuously exposed to prominent mid-to-high frequency howling noises and transient impact noises during start-stop operations, such as while waiting at red lights, queuing, or idling in underground parking garages, resulting in fatigue, irritability, and even headaches. For electric vehicles, their high quietness can actually amplify blower noise, creating a negative perception of the air conditioning system and impacting brand satisfaction. Simultaneously, long-term transient vibrations and impacts may accelerate the wear of components such as carbon brushes and motor bearings, leading to increased noise, performance degradation, and even premature blower failure, increasing maintenance costs. For models emphasizing a quiet experience, such as those with intelligent cockpits, the inability to suppress low-speed noise may also result in substandard overall NVH (Noise, Vibration, and Harshness) evaluations, negatively impacting vehicle sales and market competitiveness. Therefore, it is necessary to conduct specific optimization design for the blower noise characteristics under low-speed and start-stop conditions.

[0023] For this, please refer to Figure 1-7 As shown, a low-noise automotive air conditioning blower system includes a fan wheel 1, a blower base 2, and a motor 3; the motor 3 includes a stator component, a rotor component, a front end cover 33, a rear end cover 34, a carbon brush holder 35, a bearing, and carbon brushes 352. The wind turbine 1 is fixedly installed on the rotor assembly by a plug-in connection. The blower base 2 and the rear end cover 34 of the motor 3 are rigidly connected by screws 4, and an annular vibration damping washer 5 is provided at the connection interface. The annular vibration damping washer 5 is made of vibration damping rubber and is configured to form a flexible connection interface between the blower base 2 and the rear end cover 34 of the motor 3. An annular vibration damping ring 6 is provided between the blower base 2 and the carbon brush holder 35 of the motor 3. The annular vibration damping ring 6 is made of vibration damping rubber of the same material as the vibration damping washer and is configured to form a flexible connection interface between the carbon brush holder 35 and the blower base 2. The center line of the carbon brush 352 of the motor 3 is offset relative to the rotation center axis of the motor 3. The offset direction is configured such that when the rotor rotates clockwise, the direction of force on the carbon brush 352 is consistent with the rotation direction. The rotor component adopts a skewed lamination structure 322, wherein the rotor skewed slot 321 is inclined along the axis of the motor 3, and the inclination angle is used to uniformly distribute the air gap magnetic field between the stator and the rotor.

[0024] Specifically, the blower base 2 serves as a supporting foundation, and its upper surface is provided with a mounting plane that matches the rear end cover 34 of the motor. The mounting plane has a central array of four screw holes for fixing the motor 3. The annular damping washer 5 is made of damping rubber, with a trapezoidal concave cross-section. The outer diameter is larger than the inner diameter, creating an inward pre-compression force and forming a continuous flexible contact interface between the blower base 2 and the rear end cover 34 of the motor. The blower base 2 has a mounting groove on its side that mates with the carbon brush holder 35. The annular damping ring 6 is placed in this mounting groove, with a concave cross-section and a continuous annular groove on its inner surface. This groove fits tightly with the protruding structure on the outer edge of the carbon brush holder 35, ensuring that the damping ring does not undergo axial displacement during vibration. The carbon brush holder 35 of the motor 3 contains a carbon brush box 351. The inner wall of the carbon brush box 351 has a guide structure. The carbon brush 352 is installed in the carbon brush box 351 by a spring 353. The centerline of the carbon brush 352 is relative to the rotation center of the motor 3. The axis is offset, and the offset angle makes the carbon brush 352 and the carbon brush holder 351 form a one-sided contact fit; the rotor component is made of multiple silicon steel sheets stacked together, and the rotor skew slot 321 is inclined along the axis of the motor 3 to form a right-hand spiral distribution structure, and the inclination angle of each rotor skew slot 321 is consistent; the impeller 1 is fixedly installed on the rotor shaft 324 by the positioning ring 325 in a plug-in fit, and the blades of the impeller 1 adopt a backward curved design, with the leading edge of the blade being arc-shaped and the trailing edge being straight; the bearings include the first bearing 361 and the second bearing 362, which are respectively sleeved on the upper and lower ends of the rotor shaft 324, with the inner side forming an interference fit with the rotor shaft 324, and the outer side respectively fitting and connecting to the rear end cover 34 and the front end cover 33; the annular vibration damping ring 6 not only connects the blower base 2 and the carbon brush holder 35, but also indirectly connects the motor housing 311 and the rear end cover 34 through the vibration damping ring. The motor housing 311 and the rear end cover 34 are respectively set on the upper and lower sides of the annular vibration damping ring 6 to form an overall vibration isolation structure. This multi-level structural design ensures that the connections between components maintain the necessary mechanical stability while blocking the vibration transmission path.

[0025] The working principle and process are as follows: When the system is powered on, the current is introduced into the enameled wire 323 winding of the rotor component of the motor 3 through the carbon brush 352 and commutator 326, causing the rotor to rotate in the magnetic field generated by the stator component (composed of motor housing 311 and magnet 312). The rotating rotor drives the fan 1 through the rotor shaft 324 to work, drawing in air and accelerating its delivery. After flowing through the evaporator or heater, the air temperature is regulated, and finally it is delivered into the vehicle to achieve uniform cooling or heating of the interior space.

[0026] In terms of noise reduction mechanisms, four innovative technologies work together to suppress various types of noise generated during blower operation. An annular damping washer 5 forms a flexible connection interface between the blower base 2 and the rear end cover 34 of the motor 3. When the motor 3 vibrates during operation, the annular damping washer 5, made of damping rubber (Shore hardness 50A-60A, elastic modulus 0.25-0.3), utilizes the pre-compression force generated by its trapezoidal concave structure to maintain effective contact throughout the vibration process. Through the elastic deformation of the material, it absorbs and attenuates brush wear noise in the 1kHz-10kHz frequency band, reducing it by 15-20 dB(A). Especially when the vehicle is stationary or traveling at low speeds, and the reduced background noise inside the vehicle makes the blower noise more noticeable, this damping washer can block the transmission path of vibration from the rear end cover 34 of the motor 3 to the vehicle body structure. An annular damping ring 6 forms another flexible connection interface between the blower base 2 and the carbon brush holder 35. The annular damping ring 6, also made of damping rubber, has a continuous annular groove on its inner surface that fits tightly with the carbon brush holder 35, absorbing the mechanical noise generated by the friction between the carbon brush 352 and the commutator 326, as well as the high-frequency electromagnetic noise from electrical switching. This damping ring works in conjunction with the damping washer to block vibration transmission paths from different directions, forming a comprehensive vibration isolation system. The offset design of the carbon brush 352's centerline relative to the rotational axis of the motor 3 fundamentally solves the problem of carbon brush 352 oscillation noise. When the rotor rotates clockwise, the force on the carbon brush 352 is in the same direction as the rotation, ensuring that the carbon brush 352 stably adheres to one side of the inner wall of the carbon brush holder 351 during operation. When the spring 353 applies pressure to the carbon brush 352, since the axis of the carbon brush 352 is not on the same axis as the center of the commutator 326, the force acting on the surface of the commutator 326 is decomposed into a central component F2 and a tangential component F1. The function of F1 keeps the carbon brush 352 relatively fixed within the carbon brush holder 351, offset towards the rotation direction of the commutator 326, thus preventing the carbon brush 352 from swinging left and right and hitting the holder wall within the carbon brush holder 351. The guide structure on the inner wall of the carbon brush holder 351 forms a sliding fit with the outer surface of the carbon brush 352, ensuring that the carbon brush 352 only contacts one side of the inner wall of the carbon brush holder 351, eliminating the mechanical noise generated by the swinging of the carbon brush 352. The skewed slot lamination structure 322 of the rotor component suppresses cogging harmonic noise. The rotor skewed slots 321 are distributed in a right-hand spiral along the axis of the motor 3, and the inclination angle of each rotor skewed slot 321 is consistent. This design makes the rotor surface appear uniformly distributed when viewed from the axis of the motor 3, eliminating the non-uniformity of the air gap magnetic field caused by the rotor slots. When the permanent magnet motor 3 is running, the air gap magnetic field generated between the stator and rotor would originally be non-uniform due to the presence of the rotor slots (the air gap magnetic field is weaker at the rotor slots), generating human-sensitive harmonic noise in the 500Hz to 2kHz frequency band. The skewed slot design of this invention makes the air gap magnetic field distribution of the entire rotor uniform, eliminates the cogging harmonics, and thus suppresses the harmonic noise in this frequency band.The four noise reduction technologies mentioned above work together to maximize their effectiveness in the critical operating conditions of a stationary or low-speed vehicle. When the background noise inside the vehicle is reduced and the blower needs to operate under high load, this invention reduces the noise of the blower system through multiple measures, such as blocking the vibration transmission path, eliminating noise sources, and optimizing the air gap magnetic field distribution. In particular, it improves the comfort experience of the driver and passengers in the 500Hz to 10kHz frequency band, which is sensitive to human hearing.

[0027] This application further proposes that the annular vibration damping washer 5 is made of vibration damping rubber with a Shore hardness of 50A to 60A and an elastic modulus of 0.25 to 0.3; the cross section of the annular vibration damping washer 5 has a trapezoidal concave structure, with the outer diameter being larger than the inner diameter, forming an inward pre-compression force, and maintaining effective contact during the vibration of the motor 3 during operation.

[0028] Specifically, the material formulation of the annular vibration damping washer 5 has been specially optimized to achieve optimal damping characteristics within a Shore hardness range of 50A to 60A. The trapezoidal concave structure of the annular vibration damping washer 5 induces initial compression deformation during installation, resulting in a pre-compression of 10%-15%, ensuring that the effective contact area remains at least 80% even under maximum amplitude conditions during motor 3 operation. This structure also features self-centering; when motor 3 generates radial vibration, the sidewalls of the trapezoidal concave structure provide restoring force, guiding motor 3 back to the center position, further improving the vibration damping effect. Through this synergistic design of structure and material, the annular vibration damping washer 5 exhibits excellent vibration attenuation performance in the 1kHz-10kHz frequency band, with a vibration transmission rate of less than 0.3, suppressing the vibration energy transmitted from the rear end cover 34 of motor 3 to the blower base 2.

[0029] Through the above technical solution, this application achieves efficient vibration isolation between the rear end cover 34 of the motor 3 and the blower base 2.

[0030] This application further proposes that the annular damping ring 6 is made of damping rubber with a Shore hardness of 50A to 60A and an elastic modulus of 0.25 to 0.3MPa; the cross-section of the annular damping ring 6 is concave; the inner surface of the annular damping ring 6 is provided with a continuous annular groove, which is connected to the carbon brush holder 35.

[0031] Specifically, the annular damping ring 6 uses the same damping rubber material as the annular damping washer 5, but its structure has been optimized for the vibration characteristics of the carbon brush holder 35 area. The concave cross-section design of the annular damping ring 6 generates 3%-5% radial pre-compression in the installed state, forming a uniformly distributed contact pressure. The continuous annular groove on the inner surface has a depth of 0.1mm-0.2mm and a width of 0.3mm-0.5mm. This groove forms a labyrinthine fit with the corresponding protrusion on the outer edge of the carbon brush holder 35, preventing axial displacement of the annular damping ring 6 during vibration. The annular groove also functions to store lubricant, maintaining the lubrication of the contact surface during long-term use and reducing frictional noise. This structural design enables the annular damping ring 6 to have a loss factor as high as 0.25-0.35 in the vibration frequency range of the carbon brush holder 35 (500Hz-5kHz), which can absorb the mechanical vibration energy generated by the friction between the carbon brush 352 and the commutator 326, reduce the vibration transmission rate to below 0.25, and reduce the contribution of the carbon brush holder 35 vibration to the overall system noise.

[0032] Through the above technical solution, this application achieves efficient vibration isolation between the blower base 2 and the carbon brush holder 35, and solves the problem of high-frequency electromagnetic noise and mechanical noise transmission generated during the operation of the carbon brush 352 and the commutator 326. In particular, under the conditions of motor 3 starting and stopping and sudden speed change, it can suppress the transmission of transient vibration and improve the overall acoustic performance of the system.

[0033] This application further proposes that there are two carbon brushes 352, which are set on the carbon brush holder 35 via a carbon brush box 351. The center lines of the two carbon brushes 352 are offset relative to the rotation center axis of the motor 3 along the clockwise rotation direction of the offset rotor. One end of each carbon brush 352 is set inside the carbon brush box 351, and the carbon brushes 352 are connected to the carbon brush box 351 by a spring 353.

[0034] Specifically, the two carbon brushes 352 are arranged symmetrically, with the centerline of each carbon brush 352 offset by 4°-6° relative to the rotational axis of the motor 3, in the same direction as the expected rotation direction of the rotor (clockwise). This offset design places the contact point between the carbon brush 352 and the commutator 326 in front of the commutator 326 in the direction of rotation. When the rotor rotates, the surface of the commutator 326 applies a tangential force to the carbon brush 352 in the same direction of rotation. At the rated speed of the motor 3, this tangential force is sufficient to overcome the inertial force of the carbon brush 352 within the carbon brush holder 351, ensuring that the carbon brush 352 is stably attached to the clockwise side of the inner wall of the carbon brush holder 351. The carbon brush 352 is made of silver-graphite composite material, which has good conductivity and wear resistance. The carbon brush holder 351 has a precisely machined guide groove inside. Under the pressure of the spring 353, the carbon brush 352 only keeps in contact with one side of the guide groove, which eliminates the phenomenon of the carbon brush 352 swinging left and right in the carbon brush holder 351 in the traditional design and solves the mechanical noise problem caused by the swinging impact of the carbon brush 352.

[0035] Through the above technical solution, this application achieves stable positioning of the carbon brush during operation, eliminates the oscillation noise of the carbon brush 352, optimizes the contact state between the carbon brush 352 and the commutator 326, reduces contact sparks and wear, extends the service life of the carbon brush 352, and improves system reliability and acoustic performance.

[0036] This application further proposes that the inner wall of the carbon brush holder 351 is provided with a guide structure, which forms a sliding fit with the outer surface of the carbon brush 352; one end of the spring 353 contacts the tail of the carbon brush 352, and the other end is connected to the spring 353 mounting structure at the bottom of the carbon brush holder 351. The spring 353 extends along the movement direction of the carbon brush 352, so that the carbon brush 352 only keeps in contact with one side of the inner wall of the carbon brush holder 351 during operation.

[0037] Specifically, the guide structure on the inner wall of the brush holder 351 consists of two parallel guide ribs extending along the movement direction of the brush 352 to the bottom of the brush holder 351. Corresponding guide grooves matching the guide ribs are provided on the outer surface of the brush 352. This guide structure ensures that the brush 352 can only move in a predetermined direction, limiting its lateral oscillation freedom. The spring 353 is a helical compression spring. The spring 353 extends and is installed along the movement direction of the brush 352, ensuring that the force direction of the spring 353 is consistent with the movement direction of the brush 352, further reinforcing the tendency of the brush 352 to adhere to one side. The inner wall of the brush holder 351 also has a stop structure to prevent excessive offset of the brush 352, ensuring that the contact pressure between the brush 352 and the commutator 326 remains within the optimal range.

[0038] Through the above technical solution, this application achieves precise guidance and stable positioning of carbon brush 352 during operation, ensuring that carbon brush 352 only contacts one side of the inner wall of carbon brush box 351, eliminating the oscillation noise of carbon brush 352, optimizing the contact state between carbon brush 352 and commutator 326, improving commutation performance, reducing electrical sparks and wear, and improving the smoothness and acoustic performance of motor 3 operation.

[0039] This application further proposes that the stator component consists of a motor housing 311 and a magnet 312; the rotor component includes a rotor skew slot 321, a skew slot lamination structure 322, an enameled wire 323, a rotor shaft 324, a positioning ring 325, and a commutator 326; the rotor component is disposed inside the stator component.

[0040] Specifically, the motor housing 311 and the magnet 312 are tightly fitted together. The magnet 312 is installed on the inner wall of the motor housing 311 through both adhesive and mechanical fixing methods to ensure that it will not fall off during long-term use. The enameled wire 323 is wound in the rotor inclined slot 321 according to a specific pattern. The rotor shaft 324 is used to fix the axial position of the impeller 1 and the commutator 326.

[0041] Through the above technical solution, this application achieves high-precision matching and reliable connection of the core components of motor 3, providing a solid foundation for the noise suppression function of the rotor skew slot 321 lamination structure, while ensuring the stability and reliability of motor 3 in long-term operation, and supporting the realization of overall noise reduction effect.

[0042] This application further proposes that the skew slot lamination structure 322 of the rotor component is distributed in a right-hand spiral inclined distribution along the axis of the motor 3, and the inclination angle of each rotor skew slot 321 is consistent.

[0043] Specifically, the tilt angle of the rotor skew slot 321 is 8°-12°, and the tilt direction is distributed in a right-hand spiral along the axis of motor 3. The tilt angle of each rotor slot remains strictly consistent, with the error controlled within ±0.5°. This precisely controlled skew slot structure ensures that the rotor surface appears uniformly distributed when viewed from the axis of motor 3, eliminating the non-uniformity of the air gap magnetic field caused by the rotor slots. During the rotation of motor 3, due to the presence of the skew slot structure, the air gap magnetic permeability distribution between the stator and rotor is more uniform, reducing the fluctuation amplitude of the air gap magnetic permeability from 15%-20% of that of a conventional straight-slot rotor to 5%-8%. This uniform air gap magnetic field distribution suppresses the generation of cogging harmonics, reducing the sound pressure level in the 500Hz-2kHz frequency band from 65dB(A)-75dB(A) to 55dB(A)-60dB(A). Meanwhile, the skewed slot structure also reduces the electromagnetic vibration acceleration of motor 3 from 0.8m / s²-1.2m / s² of conventional straight slot rotor to 0.3m / s²-0.5m / s², further improving the overall vibration and noise performance.

[0044] Through the above technical solution, this application achieves the suppression of cogging harmonic noise generated during the operation of motor 3, and provides an innovative solution for mid-to-low frequency noise that is sensitive to human ears, thereby improving the acoustic comfort of the blower system and maintaining the high-efficiency characteristics of motor 3.

[0045] This application further proposes that the wind turbine 1 is fixedly installed on the rotor shaft 324 by the insertion and engagement of the positioning ring 325; the blades of the wind turbine 1 adopt a backward-curved design, with the leading edge of the blade being arc-shaped and the trailing edge being straight.

[0046] Specifically, the impeller 1 is fixedly mounted at the end of the rotor shaft 324 to prevent axial movement. The blades of the impeller 1 adopt a backward-curved design, with a rounded leading edge and a straight trailing edge, and the blade thickness gradually decreases from the leading edge to the trailing edge. This aerodynamic design reduces airflow separation and vortex generation, thus lowering aerodynamic noise. The surface of the impeller 1 is sandblasted to further optimize airflow characteristics.

[0047] Through the above technical solutions, this application achieves reliable connection and precise alignment between the impeller 1 and the rotor shaft 324. At the same time, the optimized blade design reduces aerodynamic noise, which, in conjunction with the noise reduction technology of the motor 3, improves the overall acoustic performance of the blower system and enhances the acoustic environment inside the vehicle.

[0048] This application further proposes that the bearings include a first bearing 361 and a second bearing 362, which are respectively sleeved on the upper and lower ends of the rotor shaft 324, with their inner sides attached to the rotor shaft 324 and connected to the rotor shaft 324; the outer side of the first bearing 361 is attached to the rear end cover 34, and the outer side of the second bearing 362 is attached to the front end cover 33.

[0049] Specifically, both the first bearing 361 and the second bearing 362 are deep groove ball bearings. The inner ring of the bearing is interference-fitted with the rotor shaft 324 to ensure synchronous rotation. The outer ring of the bearing is clearance-fitted with the rear end cover 34 and the front end cover 33, allowing for slight radial displacement of the outer ring, which helps absorb some vibration energy. An axial clearance is provided between the first bearing 361 (rear end bearing) and the rear end cover 34 to allow axial displacement during thermal expansion of the motor 3.

[0050] Through the above technical solutions, this application achieves precise support and stable rotation of the rotor system, reduces vibration and noise caused by bearings, and absorbs some vibration energy through reasonable matching design, working in conjunction with the overall noise reduction system.

[0051] This application further proposes that the motor housing 311 and the rear end cover 34 are not in direct contact through the annular damping ring 6; the motor housing 311 and the rear end cover 34 are connected through the annular damping ring 6; the motor housing 311 and the rear end cover 34 are respectively located on the upper and lower sides of the annular damping ring 6.

[0052] Specifically, the annular damping ring 6 not only connects the blower base 2 and the carbon brush holder 35, but also extends to the connection area between the motor housing 311 and the rear end cover 34. The outer diameter of the annular damping ring 6 is expanded to match the bottom of the motor housing 311, and the inner diameter is expanded to match the top of the rear end cover 34, forming a three-layer structure: the upper layer contacts the bottom of the motor housing 311, the middle layer is the damping rubber body, and the lower layer contacts the top of the rear end cover 34. This design prevents direct metal-to-metal contact between the motor housing 311 and the rear end cover 34, instead achieving an indirect connection through the damping ring. The motor housing 311 and the rear end cover 34 are fixedly connected by screws 4 passing through the annular damping ring 6. The screw holes are surrounded by a reinforcing structure to prevent material fatigue caused by long-term vibration. This three-layer connection structure forms a complete vibration isolation system, which not only isolates the vibration of the carbon brush holder 35, but also blocks the vibration transmission path between the motor housing 311 and the rear end cover 34, achieving comprehensive control over the overall vibration of the motor 3.

[0053] Through the above technical solution, this application achieves vibration isolation between the motor housing 311 and the rear cover 34, expands the functional range of the annular damping ring 6, blocks the vibration transmission path from multiple directions, and improves the noise reduction effect of the blower system.

[0054] In summary, an annular vibration damping washer 5 is installed between the blower base 2 and the rear end cover 34 of the motor 3, forming a flexible connection interface and blocking the transmission path of vibration from the rear end cover 34 of the motor 3 to the base. This damping washer is made of vibration-damping rubber with a Shore hardness of 50A-60A and an elastic modulus of 0.25-0.3. It is specifically optimized for brush wear noise in the 1kHz-10kHz frequency band, reducing noise in this band by 15-20dB(A) and improving high-frequency noise issues. An annular vibration damping ring 6 is installed between the blower base 2 and the carbon brush holder 35 of the motor 3. This damping ring uses the same material as the damping washer, but its structural design is optimized for the vibration characteristics of the carbon brush holder 35. By setting a continuous annular groove on the inner surface of the damping ring, the stability of the fit with the carbon brush holder 35 is enhanced, absorbing the mechanical noise generated by the friction between the carbon brush 352 and the commutator 326, as well as the high-frequency electromagnetic noise from electrical switching, thus reducing the contribution of the carbon brush holder 35 vibration to the overall system noise. The carbon brush 352 employs an asymmetrical axis design, offsetting its centerline relative to the rotation axis of the motor 3. When the rotor rotates clockwise, the force on the carbon brush 352 is aligned with the rotation direction, ensuring stable contact between the carbon brush 352 and one side of the inner wall of the brush holder 351 during operation. This avoids the phenomenon of the carbon brush 352 oscillating and impacting the holder wall within the brush holder 351, as seen in traditional designs. This design eliminates the mechanical noise generated by the oscillation of the carbon brush 352. The guide structure on the inner wall of the brush holder 351 and the sliding contact between the guide structure and the outer surface of the carbon brush 352 ensure that the carbon brush 352 maintains contact with only one side of the inner wall of the brush holder 351 during operation, thus improving noise reduction. The rotor employs a skewed slot 321 lamination structure, with the rotor slots angled along the motor's 3rd axis. The optimized angle homogenizes the air gap magnetic field distribution between the stator and rotor, eliminating cogging harmonics caused by the rotor slots. Specifically, it suppresses perceptible harmonic noise in the 500Hz–2kHz frequency band, reducing noise in this frequency range and improving the acoustic environment quality inside the vehicle. Through the synergistic effect of these four technologies, comprehensive control of blower noise is achieved, not only solving the problem of a single noise source but also eliminating the root cause of noise generation through systematic design. The offset design of the carbon brush 352 centerline reduces contact wear between the carbon brush 352 and the commutator 326, extending the service life of the carbon brush 352 and improving system reliability.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A low-noise automotive air conditioning blower system, characterized in that, It includes a wind turbine, a blower base, and a motor; the motor includes a stator assembly, a rotor assembly, a front end cover, a rear end cover, a brush holder, bearings, and carbon brushes; The wind turbine is fixedly installed on the rotor component by a plug-in connection; The blower base and the rear end cover of the motor are rigidly connected by screws, and an annular vibration damping washer is provided at the connection interface. The annular vibration damping washer is made of vibration damping rubber and is configured to form a flexible connection interface between the blower base and the rear end cover of the motor. An annular vibration damping ring is provided between the blower base and the carbon brush holder of the motor. The annular vibration damping ring is made of vibration damping rubber of the same material as the vibration damping washer and is configured to form a flexible connection interface between the carbon brush holder and the blower base. The carbon brush centerline of the motor is offset relative to the motor rotation center axis, and the offset direction is configured such that when the rotor rotates clockwise, the direction of force on the carbon brush is consistent with the direction of rotation. The rotor component adopts a skewed lamination structure, wherein the rotor skewers are inclined along the direction of the motor axis, and the inclination angle is used to uniformly distribute the air gap magnetic field between the stator and the rotor.

2. The low-noise automotive air conditioning blower system according to claim 1, characterized in that, The annular vibration damping washer is made of vibration damping rubber with a Shore hardness of 50A to 60A and an elastic modulus of 0.25 to 0.

3. The cross-section of the annular vibration damping washer has a trapezoidal concave structure, with the outer diameter being larger than the inner diameter, forming an inward pre-compression force, and maintaining effective contact during the vibration of the motor operation.

3. The low-noise automotive air conditioning blower system according to claim 1, characterized in that, The annular damping ring is made of damping rubber with a Shore hardness of 50A to 60A and an elastic modulus of 0.25 to 0.3 MPa; the cross-section of the annular damping ring is concave; the inner surface of the annular damping ring is provided with a continuous annular groove, which is connected to the carbon brush holder.

4. The low-noise automotive air conditioning blower system according to claim 1, characterized in that, There are two carbon brushes, which are set on the carbon brush holder by a carbon brush box. The center lines of the two carbon brushes are offset relative to the rotation center axis of the motor along the clockwise rotation direction of the offset rotor. One end of each carbon brush is set inside the carbon brush box and is connected to the carbon brush box by a spring.

5. The low-noise automotive air conditioning blower system according to claim 4, characterized in that, The inner wall of the carbon brush box is provided with a guide structure, which forms a sliding fit with the outer surface of the carbon brush; one end of the spring contacts the tail of the carbon brush, and the other end is connected to the spring mounting structure at the bottom of the carbon brush box. The spring extends along the direction of carbon brush movement, so that the carbon brush only keeps in contact with one side of the inner wall of the carbon brush box during operation.

6. The low-noise automotive air conditioning blower system according to claim 1, characterized in that, The stator component consists of a motor housing and magnets; the rotor component includes rotor skew slots, skew slot lamination structure, enameled wire, rotor shaft, positioning ring, and commutator; the rotor component is disposed inside the stator component.

7. The low-noise automotive air conditioning blower system according to claim 1, characterized in that, The inclined slot lamination structure of the rotor component is distributed in a right-hand spiral along the motor axis, and the inclination angle of each rotor inclined slot remains consistent.

8. The low-noise automotive air conditioning blower system according to claim 6, characterized in that, The wind turbine is fixedly installed on the rotor shaft by means of the positioning ring; the blades of the wind turbine adopt a backward-curved design, with the leading edge of the blade being arc-shaped and the trailing edge being straight.

9. The low-noise automotive air conditioning blower system according to claim 6, characterized in that, The bearing includes a first bearing and a second bearing, which are respectively sleeved on the upper and lower ends of the rotor shaft, with their inner sides attached to the rotor shaft and connected to it; the outer side of the first bearing is attached to the rear end cover, and the outer side of the second bearing is attached to the front end cover.

10. The low-noise automotive air conditioning blower system according to claim 6, characterized in that, The annular damping ring also prevents the motor housing from directly contacting the rear end cover; the motor housing and the rear end cover are connected by the annular damping ring; the motor housing and the rear end cover are respectively located on the upper and lower sides of the annular damping ring.

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