JP2015067051A - Resonator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resonator capable of suppressing change of sound absorption characteristic due to deformation caused by centrifugal force with a simple structure.SOLUTION: Inside of a flat air chamber part 36 is divided into plural sub air chambers 43 in a direction crossing to a longitudinal direction. The respective sub air chambers 43 are communicated with an air chamber by communication parts 44. Dimension in the direction crossing to the longitudinal direction is relatively suppressed to thickness of the respective sub air chambers 43, for reducing flat degree of the respective sub air chambers 43. Intensity is increased to centrifugal force generated by rotation of a wheel, and change of sound absorption characteristic due to deformation of the sub air chambers 43 due to centrifugal force can be suppressed with a simple structure.

Description

  The present invention relates to a resonator that is arranged in an air chamber between a tire and a wheel to which the tire is attached to reduce noise.

  Conventionally, for a wheel in which a rubber tire is mounted on a metal wheel, random vibration transmitted from the road surface to the tire vibrates air in the air chamber between the wheel and the tire, and near the air column resonance frequency of the air chamber. There is a known phenomenon in which a resonance phenomenon (cavity resonance) is generated and noise called air column resonance is generated. And in order to reduce this noise, the hollow air chamber part which divides the sub air chamber which communicates with an air chamber via a cylindrical communication part inside is formed in the shape of a circle in the peripheral direction of a wheel, and a communication part and A resonator (resonator) that functions as a Helmholtz resonance absorber in the auxiliary air chamber is known.

  In general, the air chamber has a small space in the radial direction of the wheel, and the air chamber portion of the resonator has a flat cross-sectional shape along the radial direction of the wheel. Therefore, for example, a structure provided with a coupling part that partially couples the air chamber part vertically in the thickness direction so that the internal auxiliary air chamber is not crushed and the sound absorption characteristics do not change when receiving centrifugal force at high speed traveling Is known (for example, see Patent Document 1).

  However, in the case of such a configuration, the portion of the coupling portion becomes thin due to the structure of the resonator. Therefore, for example, it is necessary to prevent partial unevenness due to the unevenness of the coupling portion during blow molding of the resonator.

Japanese Patent No. 4523959 (page 3-7, Fig. 1-6)

  As described above, a resonator that suppresses deformation due to centrifugal force without complicating the configuration is desired.

  The present invention has been made in view of these points, and an object of the present invention is to provide a resonator that can suppress a change in sound absorption characteristics due to deformation due to centrifugal force with a simple configuration.

  The resonator according to claim 1 is a resonator that reduces noise by being disposed in an air chamber between a tire and a wheel to which the tire is attached, and is provided in a flat shape, and is elongated along a circumferential direction of the wheel. An air chamber portion whose interior is divided in a direction intersecting the longitudinal direction by a plurality of sub air chambers having a direction, and a communication portion for communicating the sub air chamber with the air chamber, respectively.

  The resonator according to claim 2 is the resonator according to claim 1, wherein the interiors of the auxiliary air chambers are not in direct communication with each other.

  According to a third aspect of the present invention, the resonator according to the first or second aspect further comprises a connecting portion that connects the outer shells of the auxiliary air chambers along a direction intersecting the longitudinal direction.

  According to a fourth aspect of the present invention, in the resonator according to any one of the first to third aspects, each communication portion is provided side by side at one end in the longitudinal direction of each auxiliary air chamber.

  According to the resonator according to claim 1, the inside of the flat air chamber portion is divided into a plurality of sub air chambers in a direction crossing the longitudinal direction, thereby crossing the longitudinal direction with respect to the thickness of each sub air chamber. Since the flatness of each auxiliary air chamber can be reduced by relatively suppressing the dimension in the direction, the strength increases against the centrifugal force generated by the rotation of the wheel, and the deformation of each auxiliary air chamber due to this centrifugal force It is possible to suppress a change in sound absorption characteristics due to the simple configuration.

  According to the resonator according to claim 2, in addition to the effect of the resonator according to claim 1, it is possible to suppress complication of the shape by not allowing the interiors of the auxiliary air chambers to directly communicate with each other, and each auxiliary air chamber and each communication It is possible to easily control the sound absorption characteristics at the section.

  According to the resonator according to claim 3, in addition to the effect of the resonator according to claim 1 or 2, by connecting the outer shells of the auxiliary air chambers along the direction intersecting the longitudinal direction by the connecting portion, the thickness direction Therefore, the strength against the centrifugal force generated by the rotation of the wheel can be reliably maintained.

  According to the resonator of the fourth aspect, in addition to the effect of the resonator according to any one of the first to third aspects, a plurality of communicating portions are provided side by side at one end in the longitudinal direction of each auxiliary air chamber, so These communication parts can be processed together, and the productivity can be further improved.

1 is a perspective view showing a first embodiment of a resonator according to the present invention. (A) is sectional drawing of the II equivalent position of FIG. 1, (b) is sectional drawing of the II-II equivalent position of FIG. It is a perspective view which shows the wheel which attached the resonator same as the above. It is a perspective view which shows a part of 2nd Embodiment of the resonator of this invention. It is sectional drawing which shows 3rd Embodiment of the resonator of this invention.

  Hereinafter, a first embodiment of a resonator of the present invention will be described with reference to the drawings.

  1 to 3, reference numeral 10 denotes a wheel device. The wheel device 10 includes a metal wheel 11 and, for example, a plurality (four) of resonators 12 attached to the wheel 11 in the circumferential direction. A wheel of an automobile can be configured by attaching a rubber tire (not shown) to the wheel device 10.

  The wheel 11 includes a rim portion 16, a hub portion 17 located inside the rim portion 16, and a disk portion 18 that connects the rim portion 16 and the hub portion 17. The rim portion 16 is provided with a bead seat portion 21 formed along both end portions in the width direction of the wheel 11, and further projecting outward from the outer end side of the bead seat portion 21 in the radial direction of the wheel 11. A rim flange portion 22 and a well portion 23 that is located between the bead seat portions 21 and is recessed toward the inner side in the radial direction of the wheel 11 are provided. Then, by mounting the bead portion of the tire on the bead seat portion 21, an air chamber 25 having a predetermined volume, which is an annular sealed space, is surrounded by the rim portion 16 of the wheel 11 and the tire. . The well portion 23 of the rim portion 16 is provided for temporarily dropping the bead portion of the tire when the tire is assembled to the rim portion 16. Each resonator 12 is attached to the rim surface 26 that is the bottom of the well portion 23.

  A groove portion 28 as a resonator mounting portion is formed on the rim surface 26 of the well portion 23. The groove portion 28 includes a bottom surface 31 along the circumferential direction of the wheel 11, and side surfaces 32 and 32 as side portion holding surfaces raised from both sides of the bottom surface 31 along the radial direction of the wheel 11. At the upper end portions of 32 and 32, holding portions 33 and 33 that are folded back so as to face the bottom surface 31 (rim surface 26) project, and are continuous over, for example, the entire circumference of the wheel 11. That is, the holding portions 33 and 33 are located above the bottom surface 31 at a position separated from the bottom surface 31.

  Each resonator 12 can also be called a wheel resonator, and is a hollow longitudinal shape that is integrally formed by, for example, blow molding using a synthetic resin such as polypropylene or ABS, and is curved in an arc along the circumferential direction of the wheel 11. The air chamber portion 36 and locking portions 37, 37 located on both side portions in the longitudinal direction of the air chamber portion 36 are provided. The resonators 12 are fixed to the wheel 11 by the locking portions 37 and 37 being held by the holding portions 33 and 33 of the wheel 11 and being accommodated in the groove portion 28. These resonators 12 (air chamber portion 36) have a flat shape along the radial direction of the wheel 11, that is, a thickness (width) with respect to a dimension (width) in both lateral directions which is a width direction intersecting (orthogonal) with the longitudinal direction. It is set small (less than 1/2).

  The air chamber portion 36 includes a crushing portion 41 that is a non-hollow portion as a divided portion that is crushed in the thickness direction (the radial direction of the wheel 11) along the longitudinal direction at the center portion. Are divided into a plurality of sub-air chambers 43 in the present embodiment, that is, in the width direction intersecting (orthogonal) with the longitudinal direction. Further, cylindrical communication portions 44, 44 project from the air chamber portion 36 so as to communicate with the sub air chambers 43, 43.

  The crushing portion 41 is a portion that is formed into a thin wall shape by a mold (not shown) when the resonator 12 is molded, and includes a general crushing portion 47 as a divided portion main body (non-hollow portion main body) and a reinforcing portion as a connecting portion. The reinforcing crushing portions 48 are alternately provided in the longitudinal direction, and are disposed across both ends of the air chamber portion 36 in the longitudinal direction. Therefore, the sub air chambers 43 and 43 are separated by the crushing portion 41.

  Each general crushing portion 47 is formed, for example, in a thin plate shape that is crushed vertically in the thickness direction with respect to the air chamber portion 36, and is arranged in a band shape along the longitudinal direction of the air chamber portion 36.

  Each reinforcing crushing portion 48 connects the outer shells of the auxiliary air chambers 43 and 43 to reinforce against warping deformation particularly in the thickness direction. For example, the air crushing portion 36 is crushed from below in the thickness direction. And are arranged along the direction intersecting (orthogonal) with the longitudinal direction of the air chamber 36. Therefore, these reinforcing crushing portions 48 protrude upward in the thickness direction with respect to the general crushing portion 47, and are formed in a rib shape along both side directions.

  The auxiliary air chambers 43 and 43 are also called hollow portions, are elongated spaces having a longitudinal direction along the circumferential direction of the wheel 11, and the crushing portion 41 and the locking portions 37 and 37 are located on both sides. That is, the auxiliary air chambers 43 and 43 are located between the crushing portion 41 and the locking portions 37 and 37. Further, in the present embodiment, these auxiliary air chambers 43, 43 are formed, for example, in the same shape (the same cross section and the same length) and set to the same capacity. Further, these auxiliary air chambers 43, 43 are not provided with a passage or the like communicating with the outside other than the communication portions 44, 44, and the inside is not directly communicating with each other and is independent. And, the cross-sectional shape intersecting (orthogonal) with the longitudinal direction of each auxiliary air chamber 43, that is, the cross-sectional shape by a virtual plane along the radial direction of the wheel 11 is basically a shape having no sharp corners, It is formed in a shape approximate to a circle so that a dimensional ratio to the width, so-called aspect ratio, is approximately 1: 1. In other words, the auxiliary air chamber 43 has a non-flat shape having a thickness of at least 1/2 or more with respect to the width.

  Each communication portion 44 communicates each sub air chamber 43 with the air chamber 25, and is located at one end portion in the longitudinal direction of the air chamber portion 36, that is, at the same end portion side in the longitudinal direction, and protrudes in the longitudinal direction. Yes. These communicating portions 44 are arranged coaxially with the central portion of the cross section of each auxiliary air chamber 43, for example. The communication portions 44 are set to have substantially the same length, and the tip portion is, for example, a circular opening 51.

  Then, with the air chamber 25 as the main air chamber, the capacity (volume) of the sub air chamber 43, the length of the communication portion 44, and the like are set so as to satisfy the following equations for obtaining the resonance frequency of the Helmholtz resonance sound absorber.

fo = C / 2π × √ (S / V (L + α × √S))
fo [Hz]: resonance frequency of the air chamber 25 C [m / s]: sound velocity inside the air chamber 25 S [m ² ]: sectional area V [m ³ ] of the opening 51 of each communicating portion 44 of the resonator 12 Capacity of each auxiliary air chamber 43 of the resonator 12 L [m]: Length of each communicating portion 44 of the resonator 12 α: Correction coefficient

  The resonance frequency fo is set in accordance with the resonance frequency of the air chamber 25. For the plurality of resonators 12 provided in the air chamber 25, all the resonators 12 are set to the same setting. When a plurality of resonance frequencies are recognized, the resonators 12 having different settings respectively set to the resonance frequency of the air chamber 25 may be used, or may be set to an average value of the plurality of resonance frequencies of the air chamber 25. it can.

  Further, the locking portions 37, 37 are formed in a thin shape (thin plate shape) similar to the general crushed portion 47 of the crushed portion 41 by a molding die, and are continuously formed in a strip shape along the longitudinal direction of the resonator 12. Yes. That is, the locking portions 37 and 37 extend in a plate shape from both side edges of the air chamber portion 36. Further, these locking portions 37, 37 can be elastically deformed in the thickness direction. Further, these locking portions 37, 37 are formed so as to be gradually curved toward the upper side in the thickness direction, that is, outward in the radial direction of the wheel 11, as they are separated from both side edges of the air chamber portion 36. The portion comes into contact with the back side of the holding portion 33, 33, that is, the lower surface facing the bottom surface 31, so that the holding portion 33, 33 and the side surface 32, 32 of the groove portion 28 are locked in the vicinity of the corner. ing. Further, the lower surfaces of the locking portions 37, 37 are substantially flush with the lower surface of the air chamber 36, for example.

  When manufacturing this resonator 12, first, for example, a parison supplied from above to below is set in a mold cavity and closed, and air is injected into the parison to perform blow molding. After that, the intermediate body is removed, the openings 51 and 51 are opened by cutting the front ends of the communication portions 44 and 44 to the same length, and unnecessary portions (burrs) are removed, whereby the resonator 12 is completed. To do.

  When assembling the resonator 12 to the wheel 11, the resonator 12 is inserted into the groove portion 28 of the wheel 11 in an inclined manner from one of the locking portions 37, and the tip of the one locking portion 37 is held on one side. While the lower part of the air chamber part 36 is brought into contact with the bottom surface 31 by contacting the corner part between the part 33 and the one side surface 32, the tip of the other locking part 37 is connected to the other holding part 33 and the other side surface. The locking portions 37 and 37 are respectively held in the corner portions of the holding portions 33 and 33 and the side surfaces 32 and 32 by being inserted into the groove portion 28 so as to be in contact with the corner portions of the air chamber 32 and the air chamber. The part 36 is attached to the bottom surface 31. In other words, each resonator 12 is held against the radial direction of the wheel 11 by the elastic force of the locking portions 37 and 37. Each resonator 12 is fixed in the circumferential direction of the wheel 11 by a stopper (not shown) as a fixing member.

  A tire (not shown) is attached to the wheel 11 to which the resonator 12 is attached, whereby an air chamber 25 is defined between the wheel 11 and the tire, and the auxiliary air chambers 43 and 43 of each resonator 12 are provided in the air chamber 25. Communicate with each other through the openings 51 and 51 of the communication portions 44 and 44, respectively. Therefore, each resonator 12 functions as a Helmholtz resonance sound absorber, which effectively contributes to the air column resonance generated by the vibration of the air in the air chamber 25 caused by the random vibration transmitted from the road surface to the tire, which contributes to in-vehicle noise. To reduce.

  At this time, each resonator 12 divides the inside of the flat air chamber portion 36 along the radial direction of the wheel 11 into a plurality of sub air chambers 43 and 43 in a direction intersecting the longitudinal direction. The flatness of each auxiliary air chamber 43 can be reduced by relatively suppressing the dimension in the direction intersecting the longitudinal direction with respect to the thickness of the chamber 43. Therefore, the strength increases with respect to the centrifugal force generated in the radial direction of the wheel 11 by the rotation of the wheel 11, that is, in the thickness direction of the resonator 12, and deformation of each auxiliary air chamber 43 due to the centrifugal force can be suppressed. As a result, the resonance frequency of the resonator 12 set as a function of the capacity of each auxiliary air chamber 43 is stabilized, that is, the change in the sound absorption characteristics due to this deformation can be suppressed with a simple configuration, and stable sound absorption performance can be exhibited. .

  In particular, since the aspect ratio of the cross-sectional shape of each auxiliary air chamber 43 is close to 1: 1, the rigidity of each auxiliary air chamber 43 is high, for example, a state where a load is applied to the resonator 12 due to centrifugal force during high-speed traveling. However, since the auxiliary air chambers 43 are not easily deformed, stable sound absorbing performance can be exhibited.

  Moreover, when the resonator 12 is manufactured, for example, by blow molding, the auxiliary air chambers 43, 43 are long even if a thickness difference occurs vertically due to the so-called drawdown caused by the weight of the parison supplied to the mold from above. Direction, that is, along the vertical direction of the parison and side by side, respectively, so that a difference in wall thickness between the auxiliary air chambers 43 and 43 hardly occurs (the wall thickness is less than the auxiliary air chambers 43 and 43). The capacity of the auxiliary air chambers 43 and 43 is less likely to vary. Therefore, the sound absorption performance is stabilized and the management cost can be reduced.

  Further, by not allowing the insides of the auxiliary air chambers 43 and 43 to communicate directly with each other, the shape of the resonator 12 can be prevented from becoming complicated, and in particular, the crushing portion 41 can be easily formed, and each auxiliary air chamber 43 and each communicating portion 44 can be easily formed. The sound absorption characteristics can be easily controlled.

  Furthermore, by connecting the outer shells of the auxiliary air chambers 43, 43 along the both side directions intersecting (orthogonal) with the longitudinal direction by a plurality of reinforcing crushing portions 48, warpage in the thickness direction of the resonator 12 is suppressed, The strength can be reliably maintained against the centrifugal force generated by the rotation of the wheel 11, and it is not easily detached from the groove 28.

  Each communication portion 44 is provided side by side at one end in the longitudinal direction of each auxiliary air chamber 43 (all the communication portions 44 are arranged only on one side in the longitudinal direction of the resonator 12). Since the plurality of communication portions 44 can be processed together, such as opening the opening 51 by cutting the end of each communication portion 44 later, the productivity can be further improved and the lengths of the plurality of communication portions 44 are aligned. And variation in sound absorption characteristics can be reduced.

  In the first embodiment described above, for example, as in the second embodiment shown in FIG. 4, the communication portion 44 is provided at the upper part of the outer shell of each auxiliary air chamber 43 so that the radial direction of the wheel 11 is increased. You may make it open along. In this case, by arranging the communication portion 44 in the vicinity of one of the end portions, that is, side by side, when the opening portion 51 is opened by cutting the tip portion of the communication portion 44 after molding. It can be processed at a time, and the same effects as those of the above embodiments can be achieved.

  Further, in each of the above embodiments, for example, as in the third embodiment shown in FIG. 5, three auxiliary air chambers 43 may be provided in a direction intersecting (orthogonal) with the longitudinal direction of the air chamber portion 36. Four or more may be provided.

  In each of the above embodiments, the sub air chambers 43, 43 of each resonator 12 may be set to have different capacities. In this case, each of the auxiliary air chambers 43 functions as a Helmholtz resonance sound absorber having different resonance frequencies together with the respective communication portions 44, so that noise at a plurality of frequencies can be effectively reduced.

  The present invention can be applied to a resonator that is arranged in an air chamber of a wheel of an automobile or the like to reduce noise caused by resonance.

11 wheel
12 Resonator
25 Air chamber
36 Air chamber
43 Vice chamber
44 Communication part
48 Reinforced crushing part as connecting part

Claims (4)

A resonator that is arranged in an air chamber between a tire and a wheel to which the tire is attached to reduce noise,
An air chamber portion that is flat and has an interior divided in a direction intersecting the longitudinal direction by a plurality of sub air chambers having a longitudinal direction along the circumferential direction of the wheel;
A resonator comprising: a communication portion that communicates each of the auxiliary air chambers with the air chamber. The resonator according to claim 1, wherein the interiors of the sub air chambers are not in direct communication with each other. The resonator according to claim 1, further comprising a connecting portion that connects the outer shells of the auxiliary air chambers along a direction intersecting the longitudinal direction. The resonator according to any one of claims 1 to 3, wherein each communication portion is provided side by side at one end in the longitudinal direction of each sub air chamber.

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