Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
  • B60R13/00—Elements for body-finishing, identifying, or decorating; Arrangements or adaptations for advertising purposes
  • B60R13/08—Insulating elements, e.g. for sound insulation
  • B60R13/0861—Insulating elements, e.g. for sound insulation for covering undersurfaces of vehicles, e.g. wheel houses

Definitions

• the present invention is related to an application for reducing the created noise such as vibration, acoustic etc. to be applied in the Automotive/Subsidiary Industry/Material Production sector.
• the present invention is particularly related to a wheel shroud manufactured from the acoustic meta-material for reducing the wheel road noise.
• the interaction between the wheel and the road creates noise between 400-2500 Hz, some part of the noise is transferred to the cabin. It is partially realized typically in middle and high frequencies with a predetermined amount by applying the passive insulation materials on the vehicle floor or on the current wheel shroud.
• the wheel creates vertical resonance gaps on a passive material laid within the vehicle space.
• These resonators typically operate at middle and high frequencies because the dimensions of them are small. In addition to this because the thickness will increase when dimension is increased, placing and mounting the product in the wheel-vehicle cavity section becomes more difficult and the cost is increased. In addition to this, the process of perforating (puncturing process) made along the product is an important aspect which increases the costs.
• patent no EP0680866A1 comprises improvement of a passive material between the wheel and the cabin.
• acoustic resonators with various diameter and dimensions are placed on the material along the thickness. The lengths of the resonators are adjusted according to the noise frequencies and the noise coming from the wheel is tried to be reduced around the wheel. Because the dimensions of these resonators are small, they generally operate at the middle and high frequencies. In addition to this, when the dimension is increased, the thickness will also increase, then the product is placed within the wheel-vehicle cavity section, in other words assembly of the product to the wheel becomes difficult and the cost increases.
• no“US681072” there is a system which consists of a front vibrating plate and a rear face rigid place with single and double cavity. In other words it has a mechanical damper from.
• the single and double cavity may comprise absorber material.
• USB462331 is a system formed by combining the Helmholtz resonators which are previously adjusted to the targeted frequency to be dampened and the passive material in a manner such that the wheel faces the vertical axis. It needs to be used with a passive material in order to be operated in a wide band between 300-4800 Hz.
• the aim of the invention is to provide reducing the wheel-road noise transfer inside the cabin in order to eliminate the disadvantages of the present state of the art.
• the present invention provides solution to the wheel-road noise transfer inside the cabin with its acoustic meta-material wheel shroud design.
• the noise born from the wheel road interaction is one of the most significant noise sources which affect the comfort conditions in the vehicles.
• This noise with a wide band character generally occurs between 400 Hz-2500 Hz.
• the invention aims to control the noise within the acoustic cavity section formed between road-vehicle wheel space-cabin in an active manner.
• the ability of the acoustic meta-materials to reduce the noise by presenting a local resonance behaviour and filter character guarantees the very much higher noise transfer losses and noise absorption capacity compared to the current passive insulation materials which act according to the mass law principal.
• the noise caused by the wheel-road interaction is brought under control in the cavity section with a noise transfer cutter/dampener which has a low production cost, has high performance in a very wide frequency band (at low, middle and high frequencies), small thickness, is easily mountable and cheap.
• Figure 1a is a positional view of the wheel shroud at the vehicle-wheel cavity section
• Figure 1b and 1c is a view of an illustrative meta-material wheel shroud from various angles
• Figure 2a is a view of an illustrative metacell section and its position within the main material
• Figure 2b is a side (lengthwise) view of an illustrative half wave metacell
• Figure 2c is a side (lengthwise) view of an illustrative quarter wave metacell
• Figure 2d is a side (lengthwise) view of an illustrative quarter wave metacell with a hole in the middle
• Figure 2e is a side (lengthwise) of an illustrative Flelmholtz metacell
• Figure 3 is a view of the single and multilayered metacells with same or different diameters arranged in an illustrative crystal shape.
• the present invention is related to an acoustic meta-material wheel shroud (belt) (4) to be placed within the wheel-vehicle space (3) for reducing the wheel (2)-road (1 ) noise transfer to the cabin in the vehicles ( Figure 1 a).
• FIG 1 a the position of the wheel shroud (4) in the vehicle-wheel cavity section (3) is seen.
• the wheel shroud (4) of the present invention is positioned within the vehicle body space (3) independent from the wheel (2) on the upper section of the wheel (2) within the fender-vehicle body cavity space (3) where the wheel (2) is positioned.
• Figure 1 b and 1 c views of the wheel shroud (4) produced from an illustrative meta-material from various angles.
• the acoustic meta-material which forms the wheel shroud (4) of the present invention is formed by laying the acoustic metacells (5) (Figure 2a) which is flat, variable, in spring forms, with different numbers, in different arrangement combinations, with different lengths, different diameters, different thicknesses, such as quarter wave (Figure 2c, 2d), half wave ( Figure 2b) and Flelmholtz resonator (Figure 2e) by means of solid masses with elastic shell wall rigid wall (51 ) with various forms inside, under or on the main material (6) with a spring shape along the half spring frame in any desired/preferred region (Figure 1 a, 1 b, 1 c).
• Elastic or rigid metacell wall (51 ) is among the aspects which forms the acoustic metacell (5) and structural cell. It determines the vibro-acoustic resonance and applied on the shroud (4).
• metal cell internal space (52) forms the acoustic volumetric resonance.
• the main material (6) gives the shroud (4) its main shape and accommodates the metacells (5) under, on and within itself.
• the acoustic meta-material forming the wheel shroud (4) can be formed in a horizontal form from the single, double or multilayered arrangements with a phononic crystal shape with various combinations of the abovementioned various metacells (5) ( Figure 3).
• the wheel shroud (4) of the present invention is realized as the following with the three different paths separately or in combination for actively reducing the noise transmitted inside the cabin in a wide band between 20-10000 Hz:
• Said acoustic metacells (5) are adjusted according to the frequencies of the noise resulted from the wheel road interaction, they show resonance behaviour. In this manner, it distributes sound in a reverse phase and interacts with the noise within the cavity section and reduces the noise amount transmitted to the cabin.
• Metacells (5) forms a Bragg band space by being arranged in an overlapping layer manner with phononic crystal shape. Therefore it prevents the noise transmitted inside the cabin by showing a filter character.
• Structural vibration resonances of the elastic shells (51 ) arranged in said single or layered manner seen in Figure 3 reduces the noise transmitted inside the cabin by acting as a local active dampener.
• the acoustic metacells (5) can be at the end and on the surface in a manner such that it faces the wheel (2) in the inlet direction, left, middle and right sections.
• the front inlet port (53) of said metacell provides sound/noise wave inlet to some cells (5). It may have an open form or contain thin membrane at its end.
• the metacell side inlet port (54) may be open/thin membrane or closed. Again in some cells (5), the entrance of sound/noise wave is provided from the side inlet port (54).
• the metacell rear outlet port (55) may be open/thin membrane/closed. Said rear outlet port (55) provides limiting the finishing end length of the cell (5), it may be open, closed or has a thin membrane at its end.
• the metacell rigid end (56) seen in Figure 2c limits the length of the cell (5).
• FIG. 2e A side (lengthwise) view of an illustrative Helmholtz metacell (5) is shown in Figure 2e.
• the elastic or rigid large metacell wall (57) seen in Figure 2e is one of the aspects which forms the acoustic metacell (5) and structural cell. It determines the vibro-acoustic resonance.
• Large metacell internal space (58) forms the acoustic volumetric resonance.
• the main raw material of the acoustic meta material (6) can be any material such as flexible, light metal, plastic, rubber, cotton, felt based, glass wool, rock wool, petrol and textile products, also it can be produced as a matrix material. Positioning the metacells (5) under, on or within the main material (6) is performed by partial/gradual mounting or produced by means of molding. This makes the production cheaper and easier.
• the diameters of said acoustic metacells (5) are less than 20 mm. Their peripheral length is between 0,1 mm - 0,5 mm.
• the average density of said main material (6) is less than 30 g/cm 3
• the layer thickness of the main material (6) is less than 25 mm.
• the shroud (4) of the present invention absorbs/reduces the road vibration- noise between 250 - 5000 Hz.

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• Physics & Mathematics (AREA)
• Acoustics & Sound (AREA)
• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Body Structure For Vehicles (AREA)

Applications Claiming Priority (2)

Publications (2)

Family

ID=67987416

Family Applications (1)

Country Status (2)

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• 2019
  • 2019-03-09 WO PCT/TR2019/050145 patent/WO2019182544A2/en not_active Ceased
  • 2019-03-09 EP EP19770943.9A patent/EP3768577A2/de not_active Withdrawn

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