Broadband hub noise elimination structure

Abstract

The present application relates to a broadband hub noise elimination structure. A coating treatment is carried out in a cavity, which is formed by a rim and spokes, such that the smoothness of an inner wall of the cavity is improved, thereby reducing the loss of acoustic energy and then improving a noise elimination effect; moreover, partition walls are arranged in the cavity so as to divide the cavity into five noise elimination cavities having different volumes, and the noise elimination cavities cooperate with noise elimination holes for noise elimination, such that noise in a wider range of frequencies is covered, thereby improving the noise elimination effect.

Description

A wide frequency hub noise reduction structure Technical Field

[0001] The invention relates to a wide-frequency wheel hub noise reduction structure, belonging to the technical field of wheel hub production. Background Art

[0002] Wheels connect the vehicle's suspension system and tires, transmitting power and withstanding road impact, making them a major source of vehicle noise. NVH engineering improvements to wheels can reduce noise disruption to drivers and passengers, improving ride comfort. NVH engineering improvements primarily include optimizing wheel structural design, utilizing new materials, and adding sound insulation or vibration-absorbing materials.

[0003] Two-piece hollow wheels have attracted widespread attention from the wheel manufacturing industry both domestically and internationally due to their potential for lightweighting. Furthermore, the cavity of these two-piece wheels is gaining increasing attention for noise reduction applications. Current technical solutions primarily utilize the principle of Helmholtz resonance. A Helmholtz resonator or other acoustic structure is embedded within the cavity of the two-piece wheel, connected to the auxiliary air chamber via a duct, to suppress tire cavity resonance noise. In the automotive industry, quarter-wavelength tubes are commonly used in muffler designs for engine intake systems. They work by directing noise of a specific frequency into a duct, then using the duct's length and geometry to shift the sound waves of that frequency out of phase with the noise, achieving a noise reduction effect. Existing tire cavity resonance suppression technologies employ quarter-wavelength tubes by modifying the internal tire shape. However, quarter-wavelength tubes are not a commonly used design for suppressing tire cavity resonance noise. Because tire cavity resonance noise has a wide frequency range, a single quarter-wavelength tube cannot cover all frequencies. Furthermore, determining the optimal tube length and geometry in practical applications is difficult. Furthermore, embedding acoustic structures through adhesion, lap joints, or welding not only complicates the manufacturing process but also increases wheel weight, contradicting lightweighting goals. Therefore, suppressing tire cavity resonance noise requires comprehensive consideration of resonance phenomena at different frequencies and incorporating other acoustic structures and technical approaches into the design.

[0004] Summary of the Invention

[0005] The purpose of the present invention is to provide a wide frequency range hub silencer structure, which performs silencers of different frequencies through silencer cavities of different volumes, thereby achieving a wider coverage of silencer frequencies and improving the noise reduction capability of the hub.

[0006] To achieve the above object, the present invention provides the following technical solution: a wide frequency range hub noise reduction structure, the hub noise reduction structure comprising:

[0007] rims;

[0008] Spokes are connected to the rim to form a hub, and a cavity is formed between the spokes and the rim, and the inner wall of the cavity is painted;

[0009] Six partition walls are arranged in the cavity, wherein two of the partition walls are arranged on both sides of the air nozzle of the wheel hub and, together with the remaining four partition walls, divide the cavity into five silencer chambers of different volumes; and

[0010] Five silencer holes are provided on the hub and are located in the middle of the silencer cavity.

[0011] Furthermore, when the volume of the cavity is a constant value, the volume of the muffler cavity and the size of the muffler hole are determined according to the muffler frequency. The size of the muffler hole includes the aperture length, the diameter and the cross-sectional area of ​​the muffler hole, and the calculation formula is:

[0012] Where Vi is the volume of the i-th silencer cavity, S is the cross-sectional area of ​​the silencer hole, L is the aperture length of the silencer hole, d is the diameter of the silencer hole, C is the speed of sound propagation in air, and δ is the noise reduction correction coefficient.

[0013] Furthermore, the noise reduction correction coefficient δ is 0.8.

[0014] Furthermore, the mute frequencies are respectively: 162 Hz, 171 Hz, 177 Hz, 183 Hz, and 193 Hz.

[0015] Furthermore, the aperture length of the muffler hole is 4.5 mm, the diameter of the muffler hole is 3.1 mm, and the volume of the muffler cavity corresponding to the muffler frequency is: 123128, 110589, 103218, 96561, 86814 mm 3 .

[0016] Furthermore, the coating material is epoxy polyester and acrylic resin.

[0017] Furthermore, the D-ring position of the spoke is recessed to form a groove, so as to connect with the rim to form the cavity.

[0018] Furthermore, five silencer holes are provided on the rim to connect the cavity with the outside.

[0019] Furthermore, the partition wall is arranged on the spoke.

[0020] Furthermore, the rim and the spokes are connected by friction welding.

[0021] The beneficial effects of the present invention are as follows: the present application improves the smoothness of the inner wall of the cavity formed by the rim and the spokes by performing a coating process, thereby reducing the loss of sound wave energy and further improving the sound insulation effect; and a partition wall is set in the cavity to divide the cavity into five sound insulation chambers of different volumes, so as to achieve sound insulation through the sound insulation holes, thereby achieving noise coverage of a wider frequency and improving the sound insulation effect.

[0022] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] FIG1 is a schematic structural diagram of a wide audio frequency hub noise reduction structure shown in a preferred embodiment of the present application.

[0024] FIG2 is a schematic cross-sectional view of the wide audio hub noise reduction structure in FIG1 .

[0025] FIG3 is a structural diagram of a front view of the wide audio hub noise reduction structure in FIG1 .

[0026] FIG4 is a structural diagram of a rear view of the wide audio hub noise reduction structure in FIG1 . DETAILED DESCRIPTION

[0027] The following embodiments of the present invention are described in further detail with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0028] Referring to Figures 1 to 3, a wide-frequency hub noise reduction structure according to a preferred embodiment of the present application is shown. The hub noise reduction structure includes a rim 2, a spoke 1, a partition wall, and a noise reduction hole 21. The spoke 1 is connected to the rim 2 to form a hub, and a cavity is formed between the spoke 1 and the rim 2. The inner wall of the cavity is painted.

[0029] Six partition walls are provided in the cavity, two of which are provided on either side of the air nozzle 12 of the wheel hub, and the remaining four partition walls divide the cavity into five muffler chambers 11 of varying volumes. Five muffler holes 21 are provided on the wheel hub and are located in the middle of the muffler chamber 11.

[0030] In this embodiment, when the cavity is determined, the volume of the muffler cavity 11 and the size of the muffler hole 21 are determined according to the muffler frequency. The size of the muffler hole 21 includes the aperture length of the muffler hole 21, the diameter of the muffler hole 21, and the cross-sectional area of ​​the muffler hole 21, which are calculated as follows:

[0031] Wherein, Vi is the volume of the i-th silencer cavity 11, S is the cross-sectional area of ​​the silencer hole 21, L is the aperture length of the silencer hole 21, d is the diameter of the silencer hole 21, C is the speed of sound propagation in air, and δ is the silencer correction coefficient.

[0032] In this embodiment, the noise reduction correction coefficient δ is 0.8. Specifically, the noise reduction correction coefficient is a fixed value summarized based on simulation experimental data. When the noise reduction correction coefficient δ is 0.8, the noise reduction effect is optimal when the size of the noise reduction hole 21 and the volume of the noise reduction cavity 11 calculated by the formula are combined.

[0033] In this embodiment, the acoustic cavity frequency divisions are determined: the wheel's natural noise frequency without external excitation is approximately 174 Hz. At an actual vehicle speed of 100 km / h, the transmission loss frequency and noise frequency increment are approximately -15 to 16 Hz. Centered around the fundamental frequency, the quarter-wavelength tube is divided into five segments, with mute frequencies of 162 Hz, 171 Hz, 177 Hz, 183 Hz, and 193 Hz. Because sound waves passing through the Helmholtz cavity are reflected and counter-phased within the cavity, canceling out the original sound waves, this reduces the noise generated by the wheel's collision with the road surface. Five mute frequencies are set, centered around the vehicle's natural noise frequency at 100 km / h. Because tire noise increases with speed under the same road conditions, three mute frequencies above 174 Hz and two mute frequencies below 174 Hz are set to cover the highest decibel noise frequencies from low to high speeds, thereby reducing noise peaks and overall noise.

[0034] In this embodiment, the aperture length of the muffler hole 21 is 4.5 mm, the diameter of the muffler hole 21 is 3.1 mm, and the volume of the muffler cavity 11 corresponding to the muffler frequency is: 123128, 110589, 103218, 96561, 86814 mm 3 .

[0035] In this embodiment, to achieve the goal of eliminating the need for inlaying any components and thus improving the smoothness of the cavity's inner wall, the coating materials are epoxy polyester and acrylic resin. Specifically, the rim 2 and spokes 1 are pre-coated to form the inner wall of the cavity. The coating sequence is to first spray the epoxy polyester, then the acrylic resin, thereby improving the smoothness of the cavity's inner wall.

[0036] Please refer to Figures 3 and 4. In this embodiment, the D-ring position of the spoke 1 is recessed to form a groove to connect with the rim 2 to form a cavity. The silencer hole 21 is provided on the rim 2 to connect the cavity with the outside world. The silencer holes 21 correspond to the middle positions of the five silencer cavities 11 respectively.

[0037] Partition walls are set on the spoke 1, and the rim 2 is connected to the spoke 1 by friction welding. Specifically, the spoke 1 and rim 2 are separately low-pressure cast, and the material is escaped at the D-ring position of the spoke 1 to form a cavity after welding with the rim 2. Partition walls are formed on the spoke 1 to separate the cavity, dividing the cavity into silencer chambers 11 of varying volumes. The surface perpendicular to the mounting flange surface where the symmetry axis of the air nozzle 12 is located is defined as the 0° surface, and the clockwise direction is defined as the positive direction (such as direction A in Figure 3). The middle surface of the partition wall model is aligned with the 0° surface, and the partition walls are set by rotating the angles in the positive direction. The specific parameters for the setting angles of the six partition walls in this embodiment are as follows:

[0038] The rim 2 and spoke 1 are welded using friction welding. The assembled hub is placed in the retractable external welding fixture of a friction stir welding machine for inner and outer ring welding. The stir head rotates at a speed of 1500-2000 rpm, the welding speed is 350 mm / min, and the axial pressure is 2.15-3 kN. After the hub is welded, the stir head advances 15°, while the needle rotates and moves upward at a constant speed. The weld keyhole is eliminated at the final point where the needle is withdrawn. A muffler hole 11 is machined into the hub formed by welding the rim 2 and spoke 1.

[0039] Of course, in other embodiments, the number of the muffler cavities 11 may be other numbers, and the size of the muffler hole 21 and the volume of the muffler cavity 11 may be calculated using the above formula.

[0040] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0041] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A wide frequency hub noise reduction structure, characterized in that: The wheel hub noise reduction structure comprises: Rim; Spokes are connected to the rim to form a hub, and a cavity is formed between the spokes and the rim, and the inner wall of the cavity is painted; Six partition walls are arranged in the cavity, wherein two of the partition walls are arranged on both sides of the air nozzle of the wheel hub, and the remaining four partition walls divide the cavity into five silencer chambers of different volumes; and Five silencer holes are arranged on the hub and located in the middle of the silencer cavity.

2. The wide frequency hub noise reduction structure as claimed in claim 1, characterized in that: When the volume of the cavity is a fixed value, the volume of the muffler cavity and the size of the muffler hole are determined according to the muffler frequency. The size of the muffler hole includes the aperture length, the diameter and the cross-sectional area of ​​the muffler hole, and the calculation formula is: Among them, Vi is the volume of the i-th silencer cavity, S is the cross-sectional area of ​​the silencer hole, L is the aperture length of the silencer hole, d is the diameter of the silencer hole, C is the speed of sound propagation in air, and δ is the silencer correction coefficient.

3. The wide frequency hub noise reduction structure as claimed in claim 2, characterized in that: The noise reduction correction coefficient δ is 0.

8.

4. The wide frequency hub noise reduction structure as claimed in claim 3, characterized in that: The mute frequencies are: 162 Hz, 171 Hz, 177 Hz, 183 Hz, and 193 Hz respectively.

5. The wide frequency hub noise reduction structure as claimed in claim 4, characterized in that: The aperture length of the muffler hole is 4.5 mm, the diameter of the muffler hole is 3.1 mm, and the volume of the muffler cavity corresponding to the muffler frequency is: 123128, 110589, 103218, 96561, 86814 mm 3 .

6. The wide frequency hub noise reduction structure as claimed in claim 1, characterized in that: The coating materials are epoxy polyester and acrylic resin.

7. The wide frequency hub noise reduction structure as claimed in claim 1, characterized in that: The D-ring position of the spoke is recessed to form a groove, so as to be connected with the rim to form the cavity.

8. The wide frequency hub noise reduction structure as claimed in claim 7, characterized in that: The five muffler holes are arranged on the rim to connect the cavity with the outside.

9. The wide frequency hub noise reduction structure as claimed in claim 1, characterized in that: The partition walls are arranged on the spokes.

10. The wide frequency hub noise reduction structure as claimed in claim 1, characterized in that: The rim and the spoke are connected by friction welding.

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