JP2007205438A - Vibration damping device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vibration damping device having such novel structure as to develop effective damping effects in a plurality of or a wide variety of frequency bands. <P>SOLUTION: A plurality of elastic plate members 12 are laminated and laid on the surface 18 of a vibration member 16 to be damped in the laminating direction of the plurality of elastic plate members 12. The natural vibration frequency of at least one of the plurality of elastic plate members is tuned into the vibration frequency band of the vibration member to be damped. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a vibration damping device having a novel structure for reducing vibration of a vibration member.

  Conventionally, as a vibration control device for reducing vibration of a vibration member such as a car body, a window glass of a house, a fitting, etc., for example, vibration control of an asphalt sheet or a rubber sheet attached to the surface of the vibration member. Structural materials, Patent Literature 1 (Japanese Patent Laid-Open No. 4-140531), Patent Literature 2 (Japanese Patent Laid-Open No. 5-26294), Patent Literature 3 (Japanese Patent Laid-Open No. 2004-125146), Patent Literature 4 (Japanese Patent Laid-Open No. 2004). There is known a dynamic damper (dynamic vibration absorber) or the like in which a mass member is connected to and supported by a vibration member via a spring member as shown in Japanese Patent Laid-Open Publication No. -210135.

  However, in both the vibration damping structure material and the dynamic damper, in order to obtain an effective vibration damping effect, there is a problem that a large sticking area and a mass of a large mass member are required, thereby increasing the weight. It was. In addition, since the characteristics of the asphalt that constitutes the damping structure and the rubber elastic body that constitutes the spring member of the dynamic damper are easily affected by temperature, the temperature dependence of the damping effect increases and the desired damping There was a problem that it was difficult to obtain stable effects.

  In addition, in the dynamic damper, a vibration damping effect is obtained for the vibration member by tuning the natural frequency of the sub-vibration system composed of the mass-spring system to the vibration frequency region to be damped in the vibration member as the main vibration system. However, since such a damping effect can only be exerted in a relatively narrow frequency range in which the secondary vibration system is tuned, it is effective for a plurality of or a wide frequency range. The problem was difficult to be demonstrated.

  In recent years, along with the diversification of vibration members and the improvement of required damping performance, for example, a damping device as disclosed in Patent Document 5 (Japanese Patent Laid-Open No. 2001-241498) has been proposed. Such a vibration damping device has a structure in which an independent mass member is displaceable with a gap with respect to a rigid housing fixed to the vibration member. By striking through an elastic contact surface, a vibration damping effect is obtained by utilizing energy loss due to sliding friction and collision upon hitting.

  However, it is sometimes difficult to obtain a sufficient damping effect with a hit-type damping device having a conventional structure, and in particular, it is difficult to obtain an effective damping effect against a plurality of vibrations in a wide frequency range. There was a case. Moreover, a further reduction in weight has been demanded while ensuring an effective damping effect.

  In Patent Document 6 (Japanese Patent Laid-Open No. 7-293659), as in Patent Document 5, a rod-like shape having a longitudinal rod shape with a circular cross section is assumed to utilize the damping effect caused by the impact of the independent mass member. A damping device using a mass is disclosed. In this vibration damping device, a ball screw shaft, which is a vibration member, has a hollow cylindrical shape, and a rod-shaped mass is inserted and accommodated in the center hole thereof. In particular, in Patent Document 6, a plurality of bushes are externally spaced apart from each other in the axial direction of the rod-shaped mass, and the rod is adjusted by adjusting the mounting position of these bushes in the axial direction of the rod-shaped mass. It is described that the vibration suppression effect can be obtained in a plurality of frequency ranges by changing the natural frequency in the radial direction of the cylindrical mass.

  However, it is difficult to think that it is possible to change and adjust the natural frequency of a single rod-shaped mass simply by changing the mounting position of the bush on the rod-shaped mass, and effective vibration suppression effects in multiple frequency ranges It is doubtful whether it is obtained. In addition, since the contact of the rod-shaped mass with the ball screw shaft through the bush is performed on the inner and outer peripheral surfaces of the circular cross section, the contact surface is simple with dots or lines. Therefore, since the striking of the rod-shaped mass with respect to the ball screw shaft becomes simple, the vibration frequency range in which an effective vibration damping effect is exhibited is inevitably narrow.

Japanese Patent Laid-Open No. 4-140531 JP-A-5-26294 JP 2004-125146 A JP 2004-210135 A JP 2001-241498 A Japanese Patent Laid-Open No. 7-293659

  Here, the present invention has been made in the background as described above, and the problem to be solved is that the damping effect against small vibration and large vibration is advantageously exhibited in a plurality of or a wide frequency range. An object of the present invention is to provide a vibration damping device having a novel structure.

  Hereinafter, the aspect of this invention made | formed in order to solve such a subject is described. In addition, the component employ | adopted in each aspect as described below is employable by arbitrary combinations as much as possible. Further, aspects or technical features of the present invention are not limited to those described below, but are described in the entire specification and drawings, or an invention that can be understood by those skilled in the art from those descriptions. It should be understood that it is recognized based on thought.

  That is, the feature of the present invention is that a plurality of elastic plate members are provided so as to be stacked on each other, and the plurality of elastic plate members are arranged on the surface of the vibration member to be controlled in the stacking direction, In the vibration damping device, at least one natural frequency in the plurality of elastic plate members is tuned to a frequency range of vibration to be damped in the vibration member.

  In the vibration damping device having the structure according to the present invention, the elastic plate member elastically deforms itself on the surface of the vibration member or the overlapping surface of the elastic plate member, and bending vibration occurs in the elastic plate member. Occurs. Based on this bending vibration, a vibration damping effect (vibration damping effect) is exerted on the vibration member. In particular, since at least one natural frequency in the elastic plate member is tuned to a frequency range of vibration to be damped, a large vibration damping effect can be efficiently obtained by bending resonance of the elastic plate member.

  In other words, by utilizing the bending resonance of the elastic plate member itself, the elastic plate member can be efficiently lifted from the vibrating member in its entirety or partially instead of the entirety. As a result, the vibration suppression effect based on energy loss due to sliding friction or impact, such as when the elastic plate member directly hits the vibration member or the elastic plate member hits the vibration member via another elastic plate member. Is obtained. In short, by adopting the elastic plate member, the displacement of the hitting portion and its speed can be further increased based on the elastic deformation of the elastic plate member itself as compared with the rigid plate member. This energy can be obtained more effectively.

  Therefore, even if the input vibration energy is small, the elastic plate member strikes the vibration member efficiently or largely by the bending resonance action of the elastic plate member, and an effective vibration damping effect is exhibited. In particular, by adopting a plate-shaped elastic plate member, bending resonance is effectively manifested, and even if the center of gravity of each elastic plate member hardly changes, that is, the elastic plate member as a whole hardly floats from the vibrating member. Even if not, the bending resonance causes an effective hit to the vibration member. An elastic plate member preferably having a rectangular flat plate shape, more preferably a rectangular flat plate shape is employed.

  Further, due to the change in the contact surface between the elastic plate member and the vibration member due to the elastic deformation of the elastic plate member and the change in the overlapping surface of the elastic plate members, the natural frequency of the elastic plate member itself is not fixed, and to some extent It has been confirmed that it varies over the frequency range. Therefore, for example, when there are a plurality of vibration frequencies to be damped, or even if they exist in a certain frequency range, the tuning frequency is set in the frequency range including the plurality of vibration frequencies, Even with respect to vibrations in a plurality of frequency ranges and vibrations over a certain frequency range, the vibration damping effect by the hit based on the resonance action described above can be stably obtained.

  Further, since a plurality of elastic plate members are employed, the weight per elastic plate member can be reduced, and bending vibration due to desired elasticity can be easily generated. In addition, since the weight is easily secured stably over the plurality of elastic plate members, the vibration damping effect by hitting can be advantageously exerted even on a vibration member having a large weight. That is, it is avoided that bending vibration of the elastic plate member hardly occurs due to an increase in the thickness dimension of the elastic plate member in order to secure weight.

  Thus, paying attention to the resonance action of the elastic plate member itself, and using a plurality of such elastic plate members and overlapping each other, the resonance action, the natural frequency tuning performance and the weight stability can be improved. Therefore, it has become possible to realize a vibration damping device having a novel structure that is effective in the effective vibration suppression effect from small to large vibrations in a plurality of or a wide frequency range.

  In the present invention, preferably, the primary natural frequency of the elastic plate member is tuned with respect to the frequency range of vibration to be damped by the vibration member. Thereby, the basic vibration of the elastic plate member is tuned to the vibration of the resonance frequency of the vibration member, and the vibration damping effect can be obtained more efficiently.

  In particular, in the present invention, since the plurality of elastic plate members are arranged so as to overlap each other, it is possible to tune and set different natural frequencies by the number of elastic plate members. For example, by tuning the natural frequency of all elastic plate members to the frequency range of the single vibration to be damped (the same frequency range), obtaining a more effective damping effect against the vibration, or By tuning the natural frequencies of the plurality of elastic plate members to the frequency ranges of the plurality of vibrations that should be damped from each other, a damping effect can be obtained with respect to the vibrations of a plurality of or a wide frequency range. Is also possible.

  In the vibration damping device according to the present invention, a structure provided with positioning means for arranging the plurality of elastic plate members in a positioning state on the surface of the vibration member is suitably employed. According to such a structure, the elastic plate member is prevented from unnecessarily moving on the surface of the vibration member, and is stably positioned at a predetermined location on the vibration member. In addition, mutual displacement of the plurality of elastic plate members is prevented, and their overlapping state is stably maintained. Therefore, the hit state between the plurality of elastic plate members can be expressed stably, and the intended vibration damping effect can be stabilized.

  In the vibration damping device according to the present invention, a structure in which a rubber elastic layer is provided between the stacked surfaces of the plurality of elastic plate members is preferably employed. According to such a structure, generation | occurrence | production of the hitting sound accompanying the hit of elastic plate members is suppressed. In addition, it is desirable to provide a rubber elastic layer also on the contact surface between the damping target member and the elastic plate member. The rubber elastic layer may be provided independently of the elastic plate member, but may be formed by coating or attaching the surface of the elastic plate member.

In the vibration damping device according to the present invention, a structure in which each of the plurality of elastic plate members is formed of at least one of a metal material and a resin material is suitably employed. In particular, by using a metal material, the mass weight can be advantageously ensured, and the compactness and improvement of the vibration damping effect can be achieved, and the temperature dependence of the vibration damping effect can be suppressed. Further, by adopting the resin material, it is possible to suppress the hitting sound caused by the hit between the elastic plates.

  Hereinafter, in order to clarify the present invention more specifically, embodiments of the present invention will be described. First, FIG. 1 shows a vibration damping device 10 as a first embodiment of the present invention. The vibration damping device 10 includes a vibration damping plate 12 as an elastic plate member and a housing 14 as positioning means, and is superimposed on a surface 18 of an automobile body 16 as a vibration member to be a vibration damping target. It is arranged. As a result, the vibration damping device 10 is mounted on the body 16 which is the main vibration system, and constitutes a sub vibration system for the main vibration system.

  More specifically, the housing 14 includes a rectangular cup-shaped vessel member 20 and a rectangular flat plate-shaped lid member 22. The inner and outer peripheral surfaces of the bottom wall portion 24 and the peripheral wall portion 26 of the container member 20 are flat. The housing 14 is formed using, for example, a hard material such as a metal material such as iron or aluminum alloy, a synthetic resin material such as FRP, or a composite material thereof. Although not clearly shown in the drawing, the container member 20 is provided with a fixing portion for fixing to the automobile body 16. For example, a structure in which the fixing portion is formed to protrude at a plurality of locations on the outer peripheral surface of the vessel member 20 and provided with bolt insertion holes for fixing can be employed.

  The lid member 22 is disposed so as to cover the opening of the vessel member 20, and is fixed to the vessel member 20 with bolts, welding, or the like. As a result, the housing 14 has an overall shape of a substantially rectangular box, and a rectangular accommodation region 28 is provided inside. The damping plate 12 is disposed in the housing area 28.

  The damping plate 12 is formed using a metal material such as iron or aluminum, a resin material such as nylon resin, or a composite material thereof. The damping plate 12 has an appropriate size, mass, and shape in accordance with the shape and size of the mounting part (surface 18) of the automobile body 16 that is a vibration member, the mass of the mounting part, the frequency range of vibration, and the like. Although it is set and is not particularly limited, it preferably has a rectangular plate shape as illustrated.

  In particular, it is desirable that the damping plate 12 has a length dimension that is sufficiently large with respect to the thickness dimension so that bending deformation can occur. The length dimension is a dimension in the longitudinal direction (left and right in FIG. 1) of the damping plate 12. Thickness dimension: Length dimension with respect to t: L is preferably 50 ≦ L / t ≦ 10000, more preferably 100 ≦ L / t ≦ 1000. The planar shape is not necessarily rectangular, but is desirably rectangular in order to cause stable bending deformation. In this case, the width dimension B is set to 1 ≦ L / B ≦ 10 in order to effectively give a vibration damping force to the vibration member (automobile body 16). In addition, in order to stably and efficiently cause deformation due to bending resonance of the vibration damping plate 12, it is desirable that the thickness of the vibration damping plate 12 is constant throughout. Furthermore, in order to effectively exhibit the damping effect on the vibrating member, it is desirable that both the surface 18 of the vibrating member and the overlapping surface of the damping plate 12 are flat. Further, the bending strength of the damping plate 12 is taken into account when determining the thickness dimension of the damping plate 12 according to the magnitude of the input vibration, the rigidity (strength) of the vibrating member, and the like.

  Furthermore, although the mass of the damping plate 12 is determined in consideration of the vibration energy to be damped, in general, about 0.05 to 10% of the mass of the damping target portion in the automobile body 16 is preferable. More preferably, it is 0.1 to 5%. This is because if the mass is too small, it is difficult to obtain a sufficient vibration damping effect, while if the mass is too large, weighting becomes a problem.

  Therefore, a plurality of damping plates 12 as described above (for example, three in this embodiment) are prepared. The number of damping plates 12 is appropriately changed according to the desired damping effect, manufacturability, etc., and is not limited to three as illustrated.

  In this embodiment, since these three damping plates 12a, 12b, and 12c are all made of the same material, the natural frequency of each damping plate 12 is tuned based on its mass. Specifically, the length dimension, the width dimension, and the thickness dimension of the damping plate 12 will be appropriately set and changed. However, according to the experiment and the examination results of the present inventors, the width dimension is larger than the length dimension. It has been confirmed that when it becomes longer, the natural frequency shifts to the low frequency side, and it becomes difficult to obtain the desired bending resonance. Therefore, in this embodiment, only the length dimension is changed in a form in which the thickness dimension is sufficiently smaller than the length dimension and the width dimension is smaller than the length dimension. By doing so, the natural frequency of the damping plate 12 is tuned. In particular, in this embodiment, the natural vibration frequency of each damping plate 12 is made different by making the length dimensions of the three damping plates 12a, 12b, and 12c different.

  Then, the three damping plates 12a, 12b, and 12c are accommodated in the accommodating region 28 of the housing 14 in a state where they are overlapped with each other. The width dimension of each damping plate 12 is made smaller than the width dimension of the accommodation area 28, and the length dimension of the longest damping plate 12 in these damping plates 12 is larger than the length dimension of the accommodation area 28. It has been made smaller. Further, the total thickness of the three damping plates 12 a, 12 b, and 12 c is made sufficiently smaller than the height of the accommodating region 28. With the damping plate 12 positioned at the center of the accommodation area 28, between each widthwise end of the damping plate 12 and each circumferential wall portion 26 of the housing 14 and each longitudinal direction of the damping plate 12 A gap 30 having a substantially constant dimension: δ is formed between the end portion of the housing 14 and the peripheral wall portion 26 in the longitudinal direction of the housing 14. The size of the gap 30: δ is particularly limited because it is appropriately set and changed according to the required deformation or displacement of the damping plate 12 with respect to the input direction and magnitude of vibration. Not.

  In addition, there is a rubber elastic layer between the overlapping surfaces of each damping plate 12, between the damping plate 12a and the lid member 22 of the housing 14, and between the damping plate 12c and the bottom wall portion 24 of the housing 14. A rubber contact plate 32 is provided. The contact rubber plate 32 has a thin, substantially rectangular flat plate shape, and is approximately the same size as the vibration damping plate 12. In the present embodiment, the length of the contact rubber plate 32 is slightly smaller than the length of the damping plate 12.

  As the material of the abutting rubber plate 32, various rubber elastic materials such as diene rubber such as natural rubber and chlorinated rubber can be adopted. In the present invention, when the vibration damping plates 12 hit each other or vibration damping The contact rubber plate 32 is adopted mainly for the purpose of suppressing the hitting sound when the hitting sound when the plate 12 and the housing 14, and hence the automobile body 16 as a vibration member hits becomes a problem. Therefore, the rubber material and the rubber hardness are not particularly limited. When the damping plate 12 is a resin material, the contact rubber plate 32 is often unnecessary. However, for the purpose of reducing the hitting sound, a rubber elastic material having a Shore D hardness of 20 to 40 is suitably used as the contact rubber plate 32.

  The thickness dimension of the abutting rubber plate 32 is substantially constant throughout, and is preferably 0.1 to 0.3 mm. If the lid is smaller than 0.1 mm, it is difficult to obtain the desired sound reduction effect particularly when inputting low-frequency large-amplitude vibration. On the other hand, if it is larger than 0.3 mm, the damping plate 12 will be hit. This is because the vibration damping force based thereon is absorbed relatively large by the contact rubber plate 32, and it is difficult to obtain the desired vibration damping effect.

  The three damping plates 12a, 12b, 12c and the four abutting rubber plates 32a, 32b, 32c, 32d are superposed on each other, and the damping plate 12c is disposed on the housing 14 via the abutting rubber plate 32d. A gap 34 is formed between the abutting rubber plate 32a and the lid member 22 superimposed on the vibration damping plate 12a in a state of being superimposed on the bottom wall portion 24.

  In the present embodiment, in order to obtain an effective damping effect against vibrations in the main vibration input direction (up and down in FIG. 1) of the body 16, the circumferential gap 30 and the height direction in the housing region 28 of the housing 14. The gap 34 is sufficiently large to sufficiently separate the damping plate 12 and the contact rubber plate 32 from the peripheral wall portion 26 and the lid member 22. In short, it is desirable that the inner peripheral surface and the upper bottom surface of the housing 14 do not interfere with the damping plate 12 and the contact rubber plate 32 when the damping plate 12 jumps, elastically deforms, resonates, or the like. However, the superposed state of the vibration damping plate 12 and the contact rubber plate 32 is stably maintained, and the vibration damping plate 12 has a predetermined position on the body 16 (preferably vibration to be damped as described later). It is desirable to be positioned stably with respect to the portion that becomes the belly in the mode. Therefore, the size of the peripheral wall portion 26, the lid member 22 and the like of the housing 14 is set such that it can function to suppress the movement displacement of the damping plate 12 within a predetermined range while avoiding interference with the damping plate 12 as much as possible. The Rukoto.

  Specifically, for example, in the present embodiment, the dimension δ of the gap 30 formed on both sides in the horizontal direction (that is, the short side direction or the long side direction of the damping plate 12 having a rectangular flat plate shape) is: It is desirable that δ = 0.1 to 1.0 mm. In addition, the dimension of the upper gap 34 in the vertical direction (that is, the overlapping direction of the damping plate 12): h is h = 0.1 to 5.0 mm, preferably h = 0.1. It is desirable to be set to ˜1.0 mm. As a result, each damping plate 12 is prevented from moving in the horizontal direction in the accommodating region 28 of the housing 14 in each of the longitudinal direction and the width direction by being prevented from moving more than a distance of 2δ. Positioning has been performed.

  Incidentally, the dimension h of the gap 34 between the housing member 14 and the lid member 22 in the height direction of the accommodating region 28, that is, in the thickness direction (vertical direction) of the vibration damping plate 12, is set to be relatively small. However, it can be adopted as a tuning method. That is, in consideration of bending deformation and jumping displacement of the damping plate 12, the housing 14 is formed with a gap dimension h that is small enough to contact the damping plate 12. As a result, the damping plate 12 is bent and deformed or jumped and displaced, so that not only the bottom wall portion 24 (lower bottom surface) of the housing 14 but also the lid member 22 (upper bottom surface) of the housing 14 You can make positive hits. In short, the vibration damping plate 12 strikes both ends of the stroke when the vibration damping plate 12 is deformed or displaced, so that the vibration damping effect due to the hit is exerted on the automobile body 16 to be described later via the housing 14. It is also possible to act more efficiently.

  The vibration damping device 10 having such a structure is attached to the automobile body 16 by the bottom wall portion 24 of the housing 14 being superimposed on the surface 18 of the automobile body 16 and fixed by bolts, welding, or the like. ing. Here, the vibration mode (primary mode in this embodiment) of the body 16 to be damped is investigated in advance, and the housing 14 is overlaid at a position that becomes an antinode of the vibration mode. Note that it is not always necessary to match the primary mode of the body 16, and even the secondary and subsequent modes may be matched to positions that are antinodes of the vibration mode. Thereby, the vibration damping plate 12 and the contact rubber plate 32 in the vibration damping device 10 are stacked on each other and are freely supported by the housing 14, and the surface 18 of the automobile body 16 through the bottom wall portion 24 of the housing 14. Are arranged so as to overlap each other. Further, the inner peripheral surface of the bottom wall portion 24 of the housing 14 and the portion where the outer peripheral surface of the bottom wall portion 24 is overlapped in the automobile body 16, that is, the surface 18 at the position where the antinode of vibration mode is flat are mutually flat surfaces. It is said that.

  In the present embodiment, the vibration damping device 10 is mounted on the surface 18 of the automobile body 16 that extends in the horizontal direction (left and right in FIG. 1). A concrete example is shown in which the rubber contact plates 32 are superposed on each other in the vertical direction (up and down in FIG. 1) perpendicular to the surface 18 and are superposed on the automobile body 16 via the bottom wall portion 24 of the housing 14. However, it can be mounted on the surface of the automobile body 16 that is inclined with respect to the vertical direction, or can be mounted on the vertical surface. In such a case, a part or all of the vibration damping plate 12 and the contact rubber plate 32 are separated from the bottom wall portion 24 and are in contact with only the inner surface of the peripheral wall portion 26 of the housing 14. Or may be disposed in contact with both the lower bottom surface of the housing 14 and the inner surface of the peripheral wall. In any case, it is sufficient that the damping plate 12 hits the lid member 22 and the bottom wall portion 24 at the time of vibration input. As apparent from the above description, the contact surface between the body 16 and the damping plate 12 is the inner peripheral surface of the bottom wall portion 24 of the housing 14 fixed to the surface 18 of the body 16 or the surface of the damping plate 12c. The striking surface of the damping plate 12 is constituted by at least one of the lower bottom surface and the upper bottom surface of the housing 14.

  In the vibration damping device 10 as described above, a plurality of vibration damping plates 12 having relatively large elastic modulus and light weight are simply arranged so as to be overlapped in the housing 14 on the surface 18 of the body 16. Therefore, elastic deformation and jumping displacement of each damping plate 12 are largely allowed on the surface 18 of the automobile body 16 which is the main vibration system.

  For example, looking at the deformation of the vibration damping plate 12c, this deformation is caused by the fact that the central portion of the vibration damping plate 12c is in contact with the abutting rubber plate 32d from the state where the vibration damping plate 12c is in contact with the abutting rubber plate 32d (or 32c). The vibration damping plate 12 is gradually separated from the outer peripheral portion of the vibration damping plate 12 so that only the outer peripheral portion of the vibration damping plate 12 is in contact with the contact rubber plate 32d. From the state, the outer peripheral portion of the damping plate 12c is gradually separated from the contact rubber plate 32d, and only the central portion of the damping plate 12 is in contact with the contact rubber plate 32d. Or That is, along with the vibration of the automobile body 16, bending vibration is generated in the damping plate 12c, and based on this bending vibration, a vibration damping effect can be exerted on the body 16 which is the main vibration system. Depending on the input direction and magnitude of vibration, etc., the vibration damping plate 12a disposed between the contact rubber plates 32a and 32b and the vibration control plate 12b disposed between the contact rubber plates 32b and 32c, Bending vibration similar to that of the damping plate 12c appears.

  Further, the primary natural frequency f of each damping plate 12 is 0.8 to 2.0 times the primary mode vibration frequency F of the body 16 to be damped, preferably 1.0 to 1. Tuned 5 times. In other words, the relationship between the natural frequency f of each damping plate 12 and the vibration frequency F to be damping of the body 16 is 0.8 ≦ f / F ≦ 2.0, preferably 1.0. ≦ f / F ≦ 1.5. It should be noted that the vibration frequency F to be damped is the primary natural frequency of the body 16. The natural frequency f of each damping plate 12 is measured in a state where the damping plate 12 is freely supported.

  However, with the elastic deformation of the damping plate 12, the size of the contact surface between the damping plate 12 and the contact rubber plate 32 gradually increases or decreases, so that the damping plate 12 and the contact rubber plate 32 and The form supported by the body 16 via the housing 14 changes continuously. Therefore, the natural frequency of the damping plate 12 is changed, and the resonance action is exhibited over a wide frequency range. In particular, when the present inventor conducted a lot of experiments and examined, 1.0 ≦ f It was found that if /F≦1.5, a very effective vibration damping effect can be obtained.

  In particular, in the present embodiment, three damping plates 12 that exhibit such bending resonance are provided and are superposed on each other. Further, as described above, the length of each damping plate 12 is different, so that the natural frequency f of each damping plate 12 is 1.0 ≦ f / F ≦ 1.5. Each range is tuned to a different frequency range.

  Accordingly, when a vertical vibration that is a main vibration is input, at least one of the plurality of vibration damping plates 12 is efficiently lifted from the bottom wall portion 24 of the housing 14 due to bending resonance of the vibration damping plate 12. Sliding friction or impact by striking against the bottom wall 24 or the lid member 22 via the contact rubber plate 32 or striking against the bottom wall 24 or the lid member 22 via another damping plate 12. The vibration control effect based on the energy loss due to is obtained.

  Therefore, even if the input vibration energy is small, it is effective that the damping plate 12 strikes the housing 14 and the vehicle body 16 efficiently or greatly by the bending resonance action of the damping plate 12. Damping effect is demonstrated.

  Further, when the inventor examined in detail, the natural frequency of the primary bending mode in the width direction of the vibration damping plate 12 is set to the natural frequency of the automobile body 16, that is, the length of the vibration damping plate 12. By setting the mode of the direction (left and right in FIG. 1) and the mode of the width direction to different natural frequencies, a single damping plate 12 can effectively obtain a damping effect for a plurality of vibration modes. Was confirmed. Moreover, the same effect can be exhibited by the resonance of the damping plate 12 in other modes such as the torsional direction.

  For this reason as well, in the vibration damping device 10 according to the present embodiment, the rectangular plate-shaped vibration damping plate 12 is employed, so that the mode in the width direction can be effectively utilized in addition to the mode in the length direction. In addition, since energy loss due to bending resonance, sliding friction, or impact is effectively expressed, for example, even when the natural frequency of the automobile body 16 changes, the desired vibration damping effect can be stably obtained. Is recognized.

  In this regard, in the vibration damping device 10 according to the present embodiment, since a plurality of vibration damping plates 12 are employed, each vibration damping plate 12 can be reduced in weight and bending vibration due to desired elasticity is easily generated. Become. In addition, since the weight is easily secured stably in the plurality of damping plates 12 as a whole, the damping effect by hitting can be effectively obtained even for the damping target portion having a large weight in the automobile body 16. .

  Therefore, when the vibration damping device 10 is used as a vibration damping target portion, the vibration damping effect for small to large vibrations in a plurality of or a wide frequency range can be advantageously exhibited.

  In addition, in the present embodiment, the mass per damping plate 12 is reduced, and the total mass of the plurality of damping plates 12 is 0. 1 to 5%. This is a sufficiently small mass as compared with the mass of a conventional dynamic damper, a damping structure member, or the like attached to the same damping target part. Since the desired damping effect is sufficiently obtained based on the bending resonance caused by the elastic deformation of the plurality of damping plates 12, the damping plate 12 hits against the body 16 (housing 14). There is no need to set the mass of the plate 12 strictly. Therefore, it is possible to advantageously reduce the weight of the vibration damping device 10, and it is needless to say that the vibration damping device 10 is preferably used particularly for a vibration member that is severely limited in mass.

  Next, FIGS. 2 to 3 show a vibration damping device 50 as a second embodiment of the present invention. The vibration damping device 50 includes a vibration damping plate 12 and positioning bolts 52 that constitute a part of the positioning means. In the following description, members and parts having substantially the same structure as those of the first embodiment are denoted by the same reference numerals as those of the first embodiment in the drawings, and detailed descriptions thereof are given. Description is omitted.

  Specifically, the damping plate 12 according to the present embodiment has a curved plate shape that is convex in one of the thickness directions (upward in FIGS. 2 and 3), and in the longitudinal direction (left and right in FIG. 3). It extends in a section having a substantially constant curvature. The damping plate 12 is formed by, for example, pressing an elastic metal material having a rectangular flat plate shape.

  The damping plate 12 is provided with a positioning hole 54 that constitutes a part of the positioning means. The size, shape, number, position, and the like of the positioning hole 54 are not particularly limited. In the present embodiment, the positioning hole 54 has a substantially circular shape, and is spaced apart in the longitudinal direction at the center of the damping plate 12. One is provided. In addition, one or more small communication grooves 56 are provided at appropriate locations on the damping plate 12. That is, the positioning hole 54 and the communication groove 56 extend in the thickness direction of the vibration damping plate 12 and open on both upper and lower surfaces (front surface and back surface).

  Further, the damping plate 12 is provided with a rubber elastic layer 58. The rubber elastic layer 58 is integrally vulcanized and molded with the damping plate 12 using a rubber material, and is vulcanized and bonded to the front and back surfaces of the damping plate 12 through the communication groove 56 with a substantially constant thickness. In addition, a part of the thin rubber elastic layer 58 is also rotated and bonded to the outer peripheral edge of the damping plate 12 and the edge of the positioning hole 54. That is, the rubber elastic layer 58 is attached to the damping plate 12 so as to cover the damping plate 12 throughout. Similar to the contact rubber plate 32 according to the first embodiment, the rubber elastic layer 58 has a problem of hitting sound when the damping plates 12 hit each other or when the damping plate 12 and the automobile body 16 hit each other. In this case, the rubber material and the rubber hardness are not particularly limited because the main purpose is to suppress the hitting sound. In the present embodiment, since the damping plate 12 is formed of a metal material, a rubber elastic material having a Shore D hardness of 20 to 40 is suitable for the rubber elastic layer 58 for the purpose of reducing the hitting sound. Adopted.

  A plurality (three in the present embodiment) of the damping plate 12 having such a rubber elastic layer 58 are superposed on the surface 18 of the automobile body 16 in a state where they are superposed on each other in the thickness direction. Yes. The primary natural frequency f of each damping plate 12 is tuned to 1.0 to 1.5 times the vibration frequency of the primary mode F of the body 16 to be damped, and is in a different frequency range. It has been tuned.

  In particular, in the present embodiment, the vertical cross section of the rubber elastic layer 58 has a fan shape that extends along the curve direction of the vibration damping plate 12, and the end in the upper width direction (left and right in FIG. 2) It is positioned outward in the width direction from the end portion in the width direction on the side. Further, in the rubber elastic layer 58, the curvature of the surface attached to the upper surface side (upper in FIG. 2) of the damping plate 12 is attached to the lower surface side (lower in FIG. 2) of the damping plate 12. The curvature of the surface is smaller. Thereby, when the center axis | shaft of each damping plate 12 is located on substantially the same line and they are piled up, the both ends of the width direction of the lower side of one rubber elastic layer 58 are the other rubber elastic layers 58. A gap is formed between the rubber elastic layers 58 and 58. Further, when the central axis of each damping plate 12 is positioned substantially on the same line and they are stacked, the positioning holes 54 of each damping plate 12 are overlapped (up and down in FIGS. 2 and 3). It is aligned with.

  Here, the surface 18 of the automobile body 16 according to the present embodiment has a curved shape, while the surface of the rubber elastic layer 58 attached to the lower surface side of the vibration damping plate 12 has a curved shape. It has substantially the same curvature as the surface 18 of the automobile body 16. Accordingly, the surface of the rubber elastic layer 58 is overlapped with the surface 18 of the automobile body 16 with a slight gap and substantially no gap.

  A long-axis positioning bolt 52 is inserted into the positioning hole 54 of each damping plate 12 superimposed on the body 16. The outer diameter dimension of the axially intermediate portion of the positioning bolt 52 inserted through the positioning hole 54 is smaller than the diameter dimension of the positioning hole 54, so that the positioning bolt 54 is positioned between the positioning hole 54 and the positioning bolt 52. A gap is formed. Further, the tip end portion of the positioning bolt 52 is screwed and fixed to the automobile body 16. Further, the outer diameter dimension of the head of the bolt 16 is made larger than the diameter dimension of the positioning hole 54, and the uppermost position where the head of the bolt 16 is arranged in a state of being stacked on the surface 18 of the automobile body 16. The vibration damping plate 12 is positioned above the rubber elastic layer 58.

  As a result, the vibration damping device 50 is disposed on the surface of the automobile body 16, and each of the vibration damping plates 12 disposed in a superimposed state is used for positioning a plurality (two in this embodiment). Bending deformation and jumping displacement are allowed without substantially interfering with the bolt 52. When the vibration damping plates 12 are deformed or jumped, the vibration damping plates 12 or the vibration damping plates 12 and the body 16 abut against each other. As a result, as in the first embodiment, an effective damping effect is exhibited.

  In this case, when the vibration damping plate 12 is subjected to bending deformation or jumping displacement, the vibration damping plate 12 around the positioning hole 54 abuts against the axially intermediate portion of the positioning bolt 52 or the head, so that each vibration damping plate 12 The overlapping state of the plates 12 is maintained. As is clear from the above description, the positioning means of the present embodiment includes the positioning bolt 52 and the positioning hole 54.

  Particularly in the present embodiment, even when the surface 18 as illustrated is mounted on the curved automobile body 16, the vibration damping device 50 is positioned on the surface 18 with the positioning bolts 52. It is not necessary to prepare a specially-shaped housing, and the positioning mechanism can be easily realized.

  Further, since the positioning bolt 52 is provided at the center portion of the curved shape of the damping plate 12, for example, when the arrangement space on the outer periphery of the damping plate 12 is limited, the mass mass can be efficiently reduced. The mass of the damping plate 12 can be set large at the outer peripheral edge of the space that can be secured.

  In addition, since the two positioning bolts 52 are provided apart from each other in the longitudinal direction (left and right in FIG. 3) orthogonal to the bending direction, relative rotation around the central axis of each damping plate 12 can be performed. This prevents the vibration damping plate 12 from being overlaid.

  Therefore, in the vibration damping device 50 according to the present embodiment, even if the surface 18 of the automobile body 16 is not particularly flat, the plurality of vibration damping plates 12 are stably superimposed on the surface 18, The vibration control effect of the period can be obtained stably.

  Although the embodiments of the present invention have been described in detail above, these are merely examples, and the present invention is not limited to specific descriptions in these embodiments, and is based on the knowledge of those skilled in the art. The present invention can be implemented with various changes, modifications, improvements, and the like. Further, it goes without saying that such embodiments are all included in the scope of the present invention without departing from the gist of the present invention.

  For example, the shape, size, structure, number, arrangement of the vibration damping plate 12, the housing 14, and the contact rubber plate 32 with respect to the body 16 are not limited to those illustrated.

  That is, in the first embodiment, the surface 18 of the body 16, the inner and outer peripheral surfaces of the housing 14, the overlapping surface of the vibration damping plate 12 and the contact rubber plate 32, and the like are flat surfaces. However, the effects of the present invention are effectively exhibited if the housing 14 is struck at a plurality of locations in the resonance mode of the damping plate 12. Therefore, for example, one surface that abuts on each other may have irregularities, and the other surface may have a planar shape with a gap between the abutting surfaces. Alternatively, when one of the contact surfaces is a curved surface, an inclined surface, or the like, the other contact surface can have a similar shape along the surface.

  Further, the vibration damping devices 10 and 50 according to the first embodiment and the second embodiment are provided with positioning means, which are arranged according to the required vibration damping effect and manufacturability. It is a thing and is not an essential member. For example, as long as the movable region of the damping plate 12 is limited by another member, the superposed state of the damping plate 12 can be maintained, no special positioning means is necessary.

  Further, the positioning means of the damping devices 10 and 50 is not a rectangular box-shaped housing 14, positioning bolts 52, or positioning holes 54 as illustrated, but other modes that can maintain the superposed state of the damping plate 12. For example, it may be configured with a structure that does not form an accommodation space, such as a frame shape (without a lid) or a plurality of rod-shaped members that cover the outer peripheral portion of the vibration damping device and the like.

  In the first embodiment, a contact rubber plate 32 is interposed between the overlapping surfaces of the vibration damping plate 12 or between the contact surfaces to the housing 14, or in the second embodiment, Although the rubber elastic layer 58 is deposited on the surface of the vibration plate 12, the contact rubber plate 32 and the rubber elastic layer 58 need not be provided depending on the required noise reduction effect and manufacturability. Specifically, for example, the damping plate or the housing is formed of a member with a small impact sound due to contact such as a synthetic resin material or a synthetic resin coating structure, or the damping device has a relatively small vibration damping target part. In the case of mounting on a plurality of damping plates, it is possible to directly superimpose a plurality of damping plates without providing the contact rubber plate 32 and the rubber elastic layer 58. In addition, if there is a region where the occurrence of hitting at a large speed is not expected, such as the central part that becomes a node in the elastic deformation mode of the vibration damping plate, the elastic deformation of the outer peripheral edge etc. on the surface of the vibration damping plate An abutting rubber plate or a rubber elastic layer may be partially provided only in the region where the belly is in the mode.

Further, in the first embodiment, the vibration damping device 10 is provided at a position that becomes an antinode of the primary vibration mode in the body 16. For example, a plurality of vibration control plates are arranged on the antinode of one vibration mode. It is also possible to provide one or two or more vibration control devices at positions corresponding to the antinodes of a plurality of vibration modes such as a primary vibration mode and a secondary vibration mode. Note that even if the vibration damping device is disposed at a position outside the antinode of the specific vibration mode in the vibration member, a difference in the degree to which the vibration damping device is obtained is expected, but the vibration damping effect according to the present invention is effectively exhibited. obtain.

  Hereinafter, in order to verify the damping effect of the vibration damping device according to the present invention, an embodiment of the present invention will be described, but the present invention is not limited to the embodiment.

  First, an experimental apparatus 36 as shown in FIG. 4 is prepared. The experimental apparatus 36 includes a base 38 as a vibration member. The base 38 has a rectangular flat plate shape and is formed using a rigid material such as iron. Both ends of the base 38 are fixed to the vibrator 40. Further, sweep excitation or sine wave excitation by the vibration exciter 40 is applied to the base 38, or impact excitation by an impulse hammer is applied to a predetermined portion of the base 38, and the primary of the base 38 is obtained by mode analysis such as FEM. And the primary natural frequency F of the base 38 is measured.

  In addition, a vibration damping device 42 is arranged in a superimposed manner at a position that becomes an antinode of the primary vibration mode of the base 38. The damping device 42 has a structure in which four damping plates 44 as elastic plate members are stacked. These damping plates 44 employ rectangular flat plate shapes made of iron-based metal, and all have the same shape. The primary natural frequency: f of the damping device 42 including the four damping plates 44 is set to be substantially the same as the primary natural frequency: F of the base 38.

  Further, a damping device 42 ′ having a structure in which six damping plates 44 ′ having substantially the same structure as the above-described damping plate 44 are stacked is prepared. The primary natural frequency: f of the damping device 42 ′ is set to a value higher than the primary natural frequency: F of the base 62 by a predetermined amount.

  The vibration level (dB) obtained by applying a predetermined vibration force to the base 38 by the vibration exciter 40 or the impulse hammer in a state where the vibration control devices 42 and 42 ′ are superimposed on the belly of the base 38. Was measured using a known laser vibrometer 46. As a result, the measurement results of the vibration level of each base 38 provided with the vibration damping devices 42 and 42 'are shown as Examples 1 and 2 in FIG. FIG. 5 also shows as a comparative example 1 the results of measuring the vibration level of the base 38 in a state where the damping devices 42, 42 ′ are not provided on the base 38.

  In addition, a comparison device (not shown) is arranged in a superimposed manner at a position that becomes an antinode of the primary vibration mode of the base 38. The comparison device has a structure in which a rubber layer having a predetermined thickness is attached to the outer peripheral surface of a rigid member such as metal. The primary natural frequency: f of the comparison device is set to be substantially the same as the primary natural frequency: F of the base 38. The vibration level was measured by applying the same excitation force to the base 38 as in Examples 1 and 2 and Comparative Example 1. The result is shown as Comparative Example 2 in FIG.

  In the present embodiment, the mass of the base 38 is 800 g, whereas the mass of the damping device 42 is 93 g, the mass of the damping device 42 ′ is 79 g, and the mass of the comparison device is further increased. 100g. That is, the mass of the damping device 42 or the damping device 42 ′ is smaller than the mass of the comparison device. The reason why the damping device 42 ′ composed of six damping plates 44 ′ is heavier than the damping device 42 composed of four damping plates 44 is that the weight per damping plate is different. .

  From the results shown in FIG. 5 as well, in addition to the vibration damping device 42 according to the first embodiment that is tuned to substantially the same frequency range as the natural frequency F of the base 38, a predetermined amount from the natural frequency F of the base 38 is obtained. It can be seen that any of the vibration damping devices 42 ′ according to the second embodiment having a tuning frequency that deviates only by that exhibits a vibration damping effect more effectively than the comparison device according to the second comparative example.

  Further, with the vibration damping devices 42, 42 ′ superposed on the belly of the base 38 separately, an excitation force 10 times the excitation force in Examples 1 and 2 and Comparative Examples 1 and 2 is applied to the base 38. The resulting vibration level (dB) was measured. The results are shown in FIG. 6 as Examples 1 'and 2', respectively. Further, in FIG. 6, the vibration level is measured by applying the same excitation force to the base 38 as in the first and second embodiments in a state where the vibration control devices 42 and 42 ′ are not disposed on the base 38. The results are also shown as Comparative Example 1 ′. Further, a comparison device is disposed on the base 38, and the same excitation force as that of Examples 1 ′ and 2 ′ and Comparative Example 1 ′ is applied to the base 38, and the result of measuring the vibration level is referred to as Comparative Example 2 ′. Also shown.

  From the results shown in FIG. 6 as well, in the vibration damping devices 42 and 42 ′ according to Example 1 ′ and Example 2 ′, compared with the comparison device of Comparative Example 2 ′ with a large vibration input. It is recognized that the vibration damping effect is almost the same as that of the comparison device despite being lightweight. In particular, in the vibration damping device 42 ′ of Example 2 ′, it is clear that the vibration damping effect can be effectively obtained even though the natural frequency f is different from the natural frequency F of the base 38. .

Therefore, in the vibration damping device having the structure according to the present invention, even if the tuning frequency of the vibration damping devices 42 and 42 'is slightly deviated from the natural frequency F of the base 38 to be damped, a plurality of vibration damping devices are used. Based on the striking action by the resonance action of the plate 12, the vibration damping effect is exhibited over a wide frequency range, and the desired vibration damping effect is stable from small to large vibrations as illustrated. I think that it will be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectional view illustrating a vibration damping device as a first embodiment of the present invention. The longitudinal cross-sectional explanatory drawing which shows the damping device as 2nd embodiment of this invention. III-III sectional drawing in FIG. Front explanatory drawing which shows typically the experimental device which concerns on the damping device of this invention. The graph which shows the result measured about the vibration suppression effect of the experimental device in FIG. The graph which shows the result measured on the conditions different from FIG. 5 about the damping effect of the experimental device in FIG.

Explanation of symbols

10: damping device, 12: damping plate, 14: automobile body, 16: surface

Claims (4)

  A plurality of elastic plate members are provided so as to be stacked on each other, and the plurality of elastic plate members are arranged on the surface of the vibration member to be controlled in the stacking direction. A vibration damping device, wherein the vibration frequency is tuned to a frequency range of vibration to be damped in the vibration member.   The vibration damping device according to claim 1, further comprising positioning means for arranging the plurality of elastic plate members in a positioning state on the surface of the vibration member.   The vibration damping device according to claim 1 or 2, wherein a rubber elastic layer is provided between stacked surfaces of the plurality of elastic plate members. 4. The vibration damping device according to claim 1, wherein each of the plurality of elastic plate members is formed of at least one of a metal material and a resin material. 5.

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