JP2006111194A - Vehicular wheel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicular wheel capable of achieving a countermeasures for reducing the cavity resonance sound with a simple structure. <P>SOLUTION: A sound passage 6 is separately provided from a tire air chamber 5 sealed by a rim part 3 of a wheel 1 and a tire 4, both ends of the sound passage 6 are opened in the tire air chamber 5, and the length of the sound passage 6 is set to the length for damping the sound by the interference of the tire cavity resonance sound propagating in the sound passage with the tire cavity resonance sound propagating in the tire air chamber 5. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a wheel used in a vehicle, and more particularly to a cavity resonance countermeasure wheel that reduces tire cavity resonance noise.

  While the automobile is running, the tire is vibrated by the unevenness of the road surface, so that in-vehicle noise generally called tire cavity resonance is generated. This sound has a steep peak in a band of 200 Hz to 300 Hz, and is generated when an eigenmode of a donut-shaped cavity resonance system composed of a tire and a rim portion is excited by input from a road surface. Since this tire cavity resonance sound is generated regardless of the vehicle speed, it gives discomfort to the passengers of the automobile.

  In recent years, as the quietness of automobiles has increased and road noise has been reduced, tire cavity resonance noise has become more prominent. Therefore, in recent years, countermeasures against this tire cavity resonance noise have been demanded.

  Conventionally, as a method for reducing tire cavity resonance noise, a wheel that constitutes a Helmholtz resonance absorber and absorbs sound energy by resonance absorption, for example, a wheel 100 as shown in FIGS. 5 and 6 has been proposed. .

  The wheel 100 includes a sub air chamber 104 formed by a wheel rim 101, a lid member 102, and a partition wall 103. A tire main air chamber 106 formed by the lid member 102 and the tire 105 and the auxiliary air chamber 104 communicate with each other through a through hole 107.

By making this auxiliary air chamber 104 function as a Helmholtz resonance sound absorber for the tire main air chamber 106, tire cavity resonance noise is reduced (see Patent Document 1).
JP 2002-79802 A

  Since the wheel constituting the conventional Helmholtz resonance sound absorber requires a relatively wide cavity, the lid member 102, the partition wall 103, and the through hole 107 that form the auxiliary air chamber 104 must be formed. The manufacturing process becomes complicated and the manufacturing cost is high.

  Therefore, an object of the present invention is to provide a wheel that solves the above-mentioned problems by reducing tire cavity resonance noise by utilizing sound interference.

    In order to solve the above-mentioned problem, the invention according to claim 1 is provided with a sound passage separately from a tire air chamber sealed with a rim portion of a wheel and a tire, and both ends of the sound passage are connected to the tire air passage. Opening into the room, the length of the sound passage is such that the tire cavity resonance sound propagating through the sound passage interferes with the tire cavity resonance sound propagating through the tire chamber to attenuate the sound. It is characterized by setting.

  According to a second aspect of the present invention, in the first aspect of the present invention, the two openings of the sound passage are provided at positions facing each other by 180 degrees with the wheel shaft center as a center.

  The invention according to claim 3 is the invention according to claim 1 or 2, wherein the sound passage is formed by a hose, and the hose is arranged in the circumferential direction along the rim portion. .

  According to the present invention, the tire cavity resonance sound branches in one opening portion of the sound passage and propagates in the sound passage and the tire chamber, and in each other opening portion of the sound passage, Cavity resonance sounds merge. At this confluence, the phase (sound pressure) of the two cavity resonance sounds is different. For example, the sound pressure dense part on the tire chamber side and the sound pressure sparse part on the sound passage side overlap each other and cancel each other. Resonance noise can be reduced.

  According to the second aspect of the present invention, the opening of the sound passage is provided at a position that is substantially 180 degrees opposite to the wheel axis, so that the length of the sound passage and the circumference of the tire chamber between the openings are The difference from the length is always constant without being affected by the rotation angle of the tire. Therefore, a tire cavity resonance sound attenuation effect is always obtained.

  According to the third aspect of the present invention, there is no need for a wide cavity as in the Helmholtz resonance sound absorber, and it is only necessary to form the sound passage with a hose and attach the hose to the rim portion. For this reason, compared with the wheel which has a Helmholtz resonance sound absorber, the manufacturing process of a wheel is easy and manufacturing cost can be reduced.

  The best mode for carrying out the present invention will be described based on the embodiment shown in FIGS.

1 to 3 show the first embodiment.
FIGS. 1 to 3 show an example of application of the present invention to a rim wheel in which a disk and a rim are integrally formed. Applicable.

  In FIG. 1, a wheel 1 includes a disk portion 2 and a rim portion 3, and bead seat portions 3a and 3b are formed on the rim portion 3, and tires 4 are fitted and mounted on the beat seat portions 3a and 3b. A tire air chamber 5 sealed by the rim portion 3 and the tire 4 is formed.

  A hose 6 a that forms a sound passage (hereinafter also referred to as a sound passage) 6 is disposed on the back surface (inner peripheral surface) side of the drop portion 3 c of the rim portion 3.

  The hose 6a is formed in a hollow shape by an elastic material such as rubber and is closed except for the openings 6b and 6c at both ends. Note that the sound path 6 may be formed of a hose made of resin, metal or the like in addition to the elastic material of the present embodiment.

  The length of the sound passage 6 (not shown, but this length is set to L1) is set to a predetermined length, and both ends of the sound passage 6 are connected to the outer peripheral surface from the inner peripheral surface 3d of the drop portion 3c in the rim portion 3 of the wheel 1. 3e is penetrated and is connected to the tire chamber 5. As shown in FIGS. 1 and 3, the communicating portion is configured by connecting both ends of the hose 6 a to two hollow connectors 6 d and 6 e provided penetrating the drop portion 3 c. The opening portions on the tire air chamber side of the connecting devices 6d and 6e are the opening portions 6b and 6c at both ends of the sound passage 6.

  The hose 6 a is provided along the inner peripheral surface 3 d of the rim portion 3 over substantially one and a half laps in the circumferential direction of the rim portion 3. Further, the openings 6b and 6c at both ends of the sound passage 6 are provided so as to be opposed to positions of about 180 degrees centering on the central portion A of the wheel 1 as shown in FIG.

Next, the length L1 of the sound path 6 will be described.
During traveling of the automobile, the tire chamber 5 is vibrated due to the unevenness of the road surface. A tire cavity resonance sound having a wavelength λ (hereinafter referred to as the total length L2 of the tire chamber) is generated. This tire cavity resonance sound occurs regardless of the vehicle speed.

  By providing the sound passage 6 branched from the tire air chamber 5 separately from the tire air chamber 5, the tire cavity resonance sound propagates through two paths, the tire air chamber 5 and the sound passage 6. Become. At this time, at the branch point (a position where one opening 6b of the sound passage 6 extends to the center B of the tire air chamber 5 with the wheel shaft center A as the center), the inside of the tire air chamber 5 and the sound passage 6 And the tire cavity resonance sound propagating through the same phase. The tire cavity resonance sound propagates in the tire chamber 5 and the sound passage 6 having relatively different path lengths, so that the merging point (the other opening 6c of the sound passage 6 is connected to the wheel axis A). 2), the two tire cavity resonance sounds that have propagated through the tire chamber 5 and the sound passage 6 merge with a relative phase shift. It will be. Due to this phase shift, the two tire cavity resonance sounds interfere and attenuate.

  Therefore, in Example 1 of the present invention, the circumferential length (between the openings 6b and 6c centering on the axial center of the wheel 1 at the center B in the transverse section of the tire chamber 5 and the overall length L1 of the sound passage 6 ( Hereinafter, the circumferential length L3 of the tire chamber between the openings) is set so that the two tire cavity resonance sounds propagating through the sound passage 6 and the tire chamber 5 interfere and attenuate at the junction. Thus, tire cavity resonance noise is reduced.

  That is, the length L4 of the sound bypass passage (the distance from when the sound diverges to join, that is, the distance L5 from the ends of the openings 6b and 6c to the center B of the tire chamber 5 in the length of the sound passage 6) , L6) and the circumferential length L3 of the tire chamber 5 between the openings 6b and 6c (L4−L3) is expressed as a quarter wavelength (λ / 4) to 3/3 of the tire cavity resonance sound. By using four wavelengths (3λ / 4), the two tire cavity resonance sounds that have propagated through the tire chamber 5 and the sound passage 6 at the merging point are made to interfere and attenuate. . In order to further enhance the damping effect, the difference (L4−L3) between the length L4 of the sound bypass passage and the circumferential length L3 of the tire chamber between the openings is set to λ / 2 of the tire cavity resonance sound. Is preferred.

  When the difference (L4−L3) between the length L4 of the sound bypass passage and the circumferential length L3 of the tire chamber between the openings 6b and 6c is a half wavelength (λ / 2), the tire pressure at the merging point The phases of the two tire cavity resonance sounds that have propagated through the chamber 5 and the sound passage 6 are relatively shifted by 180 degrees, and the sparse and dense portions of the tire cavity resonance sound are relatively reversed. Demonstrate the maximum attenuation effect due to interference.

  Depending on the position where the openings 6b and 6c are provided, two types of circumferential length L3 of the tire air chamber between the openings 6b and 6c occur depending on the rotation angle of the wheel. For example, when the openings 6b and 6c are provided at a position of 90 degrees about the axis A of the wheel 1, the circumferential length L3 of the tire chamber between the openings 6b and 6c is (L2) depending on the rotation angle of the wheel 1. There are two types of × 1/4 and (L2) × 3/4.

  However, when the openings 6b and 6c are provided at positions that are substantially 180 degrees opposite to each other about the axis A of the wheel 1, the length L4 of the sound bypass passage and the circumferential length L3 of the tire chamber between the openings 6b and 6c. (L4−L3) is always constant without being influenced by the rotation angle of the tire. Therefore, a tire cavity resonance sound attenuation effect is always obtained.

  Therefore, in the first embodiment, in order to increase the damping effect, the difference (L4−L3) between the length L4 of the sound bypass passage and the circumferential length L3 of the tire chamber between the openings 6b and 6c is reduced by half. The wavelength was set to (λ / 2). Further, since the sound passage 6 (that is, the hose 6a) is wound along the inner peripheral surface 3d of the rim portion 3 of the wheel 1, one circumferential length of the tire chamber 5 around the center A of the wheel 1; Since the circumference of the sound passage 6 (the hose 6a) is different, the hose 6a is wound half and a half, and the openings 6b and 6c are located at positions where the density of the tire cavity resonance sound is most different. In other words, they are provided at positions that face each other by 180 degrees around the axis A of the wheel 1.

  The cross-sectional area of the sound passage 6 is arbitrarily set. Since the cross-sectional area of the sound passage 6 is closer to the cross-sectional area of the tire chamber 5, the damping effect is higher. This is because, when the two tire cavity resonance sounds are interfered and attenuated, the closer the cross-sectional area of the two tire cavity resonance sounds to be interfered with, the higher the effect of attenuation of the tire cavity resonance sounds.

  By setting in this way, two tire cavity resonances having different phases by 180 degrees interfere with each other at the junction 6c where the density of the tire cavity resonances in the tire chamber 5 is the most sparse, and a high damping effect is obtained. Demonstrate.

Next, the result of the silencing experiment in the above embodiment will be described.
As a condition, the wheel 1 having an outer diameter 3b of the rim portion 3 of 400 mm and the tire 4 having an inner diameter of the tire 4 of 660 mm are used. It is provided at a position facing about 180 degrees with respect to one axis A. The inner diameter of the hose 6a is about 10 mm.

  In this case, the total length L2 of the tire chamber is 1665 mm. Since the tire cavity resonance sound is such that the entire length L2 of the tire chamber 5 is one wavelength λ, the half wavelength (λ / 2) of the tire cavity resonance sound is 833 mm. The circumferential length L3 of the tire chamber 5 between the openings 6b and 6c is 833 mm. The difference (L4−L3) between the length L4 of the sound bypass passage and the circumferential length L3 of the tire chamber 5 between the openings 6b and 6c is set to a half wavelength (λ / 2 = 833 mm) of the tire cavity resonance sound. Therefore, the length L4 of the sound bypass passage was set to 1666 mm (L3 + λ / 2). Since the distance (L5 + L6) from the ends of both openings 6b, 6c to the center B of the tire chamber 5 is 130 mm, the length L1 of the sound passage 6 is set to 1536 mm.

  The result of actually confirming the sound reduction effect with this setting is shown in FIG. FIG. 4 shows a frequency response function in a comparative product in which the countermeasure for cavity resonance of the present invention is not applied to the wheel 1 and the tire 4 and a product of the present invention in which the sound path 6 is attached. The broken line X represents the characteristics of the comparative product, and the solid line Y represents the characteristics of the present invention.

  From this result, in the wheel in the first embodiment, in the tire cavity resonance sound having a peak at about 220 Hz, the sound pressure level is reduced by about 2 dB as shown by the reference symbol Z, as compared with the wheel of the comparative product. did it.

  In the first embodiment, as shown in FIG. 1, a hose 6 a that is a sound passage 6 is provided on the vehicle body side of the disk portion 2 of the wheel 1 and on the inner peripheral surface 3 a side of the rim portion 3 of the wheel 1. The sound passage 6 may be provided in the tire air chamber 5, and both open ends 6 b and 6 c of the sound passage 6 may be opened in the tire air chamber 5.

The length of the sound path in this case is the same as that in the first embodiment.
Also in the second embodiment, the same effects as in the first embodiment are obtained.

Other examples

  In the first embodiment, only one sound passage 6 is provided, but by providing a plurality of sound passages 6, the effect of attenuating tire cavity resonance sound can be further enhanced.

  In Example 1, as shown in FIG. 1, both end openings 6 b and 6 c of the sound passage 6 are provided on the outer peripheral surface 3 e of the rim portion 3, but both end openings 6 b and 6 c of the sound passage 6 are You may provide in any part in the tire air chamber 5. FIG. For example, a sound passage may be formed using a hollow portion inside the wheel. Further, if both end openings 6b and 6c of the sound passage 6 are provided in a portion close to the central portion B of the tire air chamber 5, the attenuation effect of the tire cavity resonance sound can be further enhanced.

The perspective view which showed the Example of this invention and assembled | attached the tire to the wheel. The front view which shows the Example of the wheel of this invention. The partial cross section perspective view of the principal part in FIG. The characteristic diagram which shows the tire cavity resonance sound of this invention product and the comparison product The partial cross section perspective view which shows the conventional wheel. FIG. 6 is a longitudinal sectional view of the wheel of FIG. 5.

Explanation of symbols

1 Wheel 3 Rim 4 Tire 5 Tire Air Chamber 6 Sound Path (Sound Path)
6a Hose 6b, 6c Opening L1 Length of sound passage L2 Overall length of tire chamber L3 Circumference of tire chamber between openings L4 Length of bypass passage of sound

Claims (3)

  A sound passage is provided separately from the tire chamber sealed by the rim portion of the wheel and the tire, both ends of the sound passage are opened into the tire chamber, and the length of the sound passage is determined by the length of the sound passage. A vehicle wheel characterized in that the length is set such that the tire cavity resonance sound propagating in the passage and the tire cavity resonance sound propagating in the tire chamber interfere to attenuate the sound.   2. The vehicle wheel according to claim 1, wherein both openings of the sound passage are provided at positions that oppose each other by 180 degrees about the axis of the wheel. The vehicle wheel according to claim 1, wherein the sound passage is formed by a hose, and the hose is disposed in a circumferential direction along the rim portion.

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