Vibration damping structure and automobile equipped with said vibration damping structure

Abstract

To provide a vibration control structure that is hard to deteriorate over time and has high durability over a long term even when exposed to external environment.SOLUTION: A vibration control structure of the present invention comprises a metal vibration control plate having at least a wedge-shaped part, and a metal plate in contact with a tip part of the metal vibration control plate. Since a plate thickness of the wedge-shaped part changes so as to satisfy the following equation (1) and the metal plate is provided so as to be able to rub against the metal vibration control plate while the vibration control structure is manufactured only with metal members, it is possible to provide a vibration control structure that is hard to deteriorate over time and has high durability. h(x)=ε xn+h0 ... Equation (1). In the equation (1), x represents a distance (mm) from a thin wall-side tip of the wedge-shaped part, h(x) represents a plate thickness (mm) at the distance x from the thin wall-side tip of the wedge-shaped part, h0 represents a thickness (mm) of a thin end of the wedge-shaped part, ε represents a positive constant, and n represents a real number of 1 or more.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a vibration-damping structure and a vehicle equipped with the vibration-damping structure, and more particularly to a vibration-damping structure that utilizes the acoustic black hole effect and a vehicle equipped with the vibration-damping structure. [Background technology]

[0002] As a countermeasure against vibration and noise, it is known to use a vibration control structure that utilizes the acoustic black hole effect.

[0003] This vibration-damping structure has a wedge-shaped structure in which the plate thickness decreases toward the tip.The vibrations (waves) propagating through this vibration-damping structure increase in amplitude and their propagation speed slows as they approach the tip.At the tip of the wedge, where the plate thickness becomes 0 (zero), the propagation speed becomes 0 and the vibrations are not reflected.This is what is used.

[0004] However, it is not possible to actually manufacture a wedge-shaped vibration-damping structure whose tip has a thickness of zero, and it is not possible to completely eliminate vibration reflection, so a damping material is provided at the tip of the wedge to reduce the reflection.

[0005] Patent Document 1 discloses an elastic wedge damper that attenuates vibration energy by attaching a damping material made of a polymer film to the tip of a wedge where vibration energy is concentrated. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-144868 Summary of the Invention [Problem to be solved by the invention]

[0007] However, the vibration control structure described in Patent Document 1 uses resin for the damping material and the adhesive used to attach the damping material, which is prone to deterioration over time and has low long-term durability, so it cannot be applied to automobiles and other vehicles that are exposed to the external environment and are subject to large environmental changes.

[0008] The present invention has been made in consideration of the problems associated with the prior art, and its object is to provide a vibration-damping structure that is resistant to deterioration over time and has high durability over a long period of time. [Means for solving the problem]

[0009] As a result of extensive research into achieving the above object, the inventors discovered that the above object could be achieved by fabricating a vibration control structure using only metal members, and thus completed the present invention.

[0010] That is, the vibration damping structure of the present invention comprises at least a metal vibration damping plate having a wedge-shaped portion, and a metal plate abutting against the tip end of the metal vibration damping plate. The thickness of the wedge-shaped portion varies to satisfy the following formula (1), and the metal plate is provided so as to be able to frictionally contact the metal vibration damping plate: h(x) = ε x n + h0...Equation (1) However, in formula (1), x: Distance from the thin end of the wedge (mm) h(x): Plate thickness at distance x from the thin end of the wedge (mm) h0: Plate thickness of the thin end of the wedge (mm) ε: positive constant n: real number greater than or equal to 1

[0011] The automobile of the present invention is characterized by including the above vibration damping structure. [Effects of the Invention]

[0012] According to the present invention, the vibration-damping structure is manufactured using only metal components without using resin materials, making it possible to provide a vibration-damping structure that is resistant to deterioration over time and has high durability over a long period of time. [Brief explanation of the drawings]

[0013] [Figure 1] 1A and 1B are diagrams illustrating a vibration damping mechanism by the vibration damping structure of the present invention. [Figure 2] 1 is a diagram illustrating the shapes of the wedge-shaped metal vibration damping plate and the metal plate used in the examples and comparative examples. FIG. [Figure 3] 10 is a graph showing the results of measuring the inertance of the vibration damping structure of Comparative Example 1. [Figure 4] 10 is a graph showing the results of measuring the inertance of the vibration damping structure of Comparative Example 2. [Figure 5] 10 is a graph showing the results of measuring the inertance of the vibration damping structure of Comparative Example 3. [Figure 6] 4 is a graph showing the results of measuring the inertance of the vibration damping structure of Example 1. [Figure 7] 10 is a graph showing the results of measuring the inertance of the vibration damping structure of Example 2. [Figure 8] 10 is a graph showing the results of measuring the inertance of the vibration damping structure of Comparative Example 4. [Figure 9] 10 is a graph showing the results of measuring the inertance of the vibration damping structure of Example 3. [Figure 10] 10 is a graph showing the results of measuring the inertance of the vibration damping structure of Example 4. [Figure 11] FIG. 2 is a diagram illustrating the shapes of the disk-shaped metal vibration damping plate and the metal plate used in the examples and comparative examples. [Figure 12] 10 is a graph showing the results of measuring the inertance of the vibration damping structure of Comparative Example 5. [Figure 13] 10 is a graph showing the results of measuring the inertance of the vibration damping structure of Comparative Example 6. [Figure 14] 10 is a graph showing the results of measuring the inertance of the vibration damping structure of Example 5. [Figure 15]1 is a diagram illustrating the shapes of a cone-shaped metal vibration damping plate and a metal plate used in Examples and Comparative Examples. FIG. [Figure 16] 10 is a graph showing the results of measuring the inertance of the vibration damping structure of Comparative Example 7. [Figure 17] 10 is a graph showing the results of measuring the inertance of the vibration damping structure of Comparative Example 8. [Figure 18] 10 is a graph showing the results of measuring the inertance of the vibration damping structure of Example 6. DETAILED DESCRIPTION OF THE INVENTION

[0014] The vibration damping structure of the present invention will now be described in detail. The vibration damping structure of the present invention includes a metal vibration damping plate and a metal plate. The metal damping plate has a wedge-shaped portion whose thickness gradually decreases toward the free end, and the metal plate is provided at the tip of the free end of the metal damping plate so as to be in frictional contact with the metal damping plate.

[0015] The metal damping plate has an acoustic black hole effect when the wedge-shaped portion satisfies the following formula (1) and the plate thickness changes. h(x) = ε x n + h0...Equation (1) However, in formula (1), x: Distance from the thin end of the wedge (mm) h(x): Plate thickness at distance x from the thin end of the wedge (mm) h0: Plate thickness of the thin end of the wedge (mm) ε: positive constant n: real number greater than or equal to 1

[0016] As shown in Figure 1, in a metal vibration damping plate with a wedge-shaped portion that satisfies equation (1), incident vibrations (waves) propagate toward the free end of the metal vibration damping plate in the direction in which the thickness of the plate decreases, and the amplitude increases and the propagation speed slows down as it approaches the tip.

[0017] The metal vibration damping plate of the present invention has a metal plate that is frictionally abutted against the tip of the free end, which has a large amplitude and a slow propagation speed, so that the vibration energy propagated to the tip of the free end is converted into frictional heat and attenuated.

[0018] Therefore, the vibration damping structure can suppress vibration at the free end even if the plate thickness (h0) at the free end of the metal vibration damping plate is not zero.

[0019] Furthermore, in the present invention, a metal plate is used as the damping material, which has superior weather resistance, is less susceptible to deterioration over time, and is highly durable compared to resin damping materials, making it possible to damp vibrations over a long period of time.

[0020] In the present invention, the "free end tip" refers to the free end of the main surface of the metal vibration damper and the tip portion that continues from the free end in the direction in which the thickness of the metal vibration damper increases, and does not refer to the end face or side portion of the free end of the metal vibration damper. Furthermore, "frictionable" means that it is sufficient for the metal damping plate and the metal plate to partially rub against each other due to microscopic expansion and contraction of the metal damping plate caused by the metal damping plate rippling due to input of vibration, and does not mean that the metal damping plate and the metal plate move relative to each other and the overall positional relationship between the metal damping plate and the metal plate changes.

[0021] In the above-mentioned vibration-damping structure, the edge of the metal plate and the free end of the metal vibration-damping plate overlap tightly, thereby efficiently suppressing vibration at the free end. Also, the entire main surface of the metal plate abuts against the main surface of the metal vibration-damping plate, increasing the contact area between the metal plate and the metal vibration-damping plate, thereby efficiently converting the vibration energy of the metal vibration-damping plate into frictional heat.

[0022] The size of the metal plate needs only to be able to damp the vibration of the free end through friction, and although it depends on the energy and frequency of the input vibration, the size is adjusted according to the plate thickness (h0) of the free end.

[0023] Specifically, although it depends on the type of metal plate, the thickness of the metal plate is preferably about the same as the thickness of the free end, preferably 0.1 to 0.3 mm, and the length from the free end is preferably 5 to 30 mm.

[0024] The thickness (h0) of the free end is preferably as thin as possible so long as the metal damper plate is not deformed by the weight of the metal plate itself or the weight of the metal plate and can maintain its shape, and is preferably 0.1 to 0.3 mm.

[0025] Furthermore, the length of the wedge-shaped portion of the metal vibration damping plate, i.e., the length from the point where the thickness of the metal vibration damping plate begins to decrease to the free end, should be sufficient to concentrate the input vibrations at the tip, and is preferably 20 to 2000 mm, although this depends on the thickness of the thick portion of the metal vibration damping plate.

[0026] The thickness of the thick portion of the metal vibration damping plate is preferably 0.5 to 50 mm.

[0027] The wedge-shaped portion of the metal vibration damping plate may have a thickness that gradually decreases toward the free end, and both of the one and the other main surfaces may be formed as flat surfaces or curved surfaces, or one main surface may be formed as a flat surface and the other main surface may be formed as a curved surface.

[0028] The overall shape of the metal vibration damping plate is not particularly limited as long as it has a wedge-shaped portion, and examples include polygonal shapes such as squares and rectangles, as well as circles and ellipses.The free end of the wedge-shaped portion may face the outside of the metal vibration damping plate, or may face the inside of the metal vibration damping plate (towards the center or central part) and be mortar-shaped.

[0029] Furthermore, the metal damping plate may have a thin portion with a constant thickness on the thin side (free end side) of the wedge portion, as required, the thickness of which is the same as the thickness of the thin end of the wedge portion. When the metal damping plate has a thin portion, the metal plate is provided at the tip of the free end of the thin portion.

[0030] The metal damping plate may further have a thick portion on the thick side of the wedge-shaped portion, the thickness of which is constant and the same as the thickness of the thick end of the wedge-shaped portion.

[0031] Methods for frictionally contacting the metal plate with the metal vibration damping plate include a method in which the overlapping metal plate and the metal vibration damping plate are sandwiched between a metal elastic member, and a method in which they are fastened together with a metal fastening member.

[0032] Examples of the metallic elastic members include clips and leaf springs, and examples of the metallic fastening members include bolts and nuts.

[0033] As the metal vibration damping plate or metal plate, any metal material that has conventionally been used as a vibration damping plate can be used, such as iron, aluminum, zinc, nickel, tin-lead, copper, and alloys containing these.

[0034] The metal damping plate and the metal plate are preferably made of the same metal material, but when different metal materials are used, it is preferable that the natural potential of the metal plate is lower than the natural potential of the metal damping plate.

[0035] By using a metal plate made of a metal material that is less noble than the metal vibration damping plate, corrosion of the metal vibration damping plate can be prevented, changes in the vibration damping effect can be suppressed, and durability can be improved.

[0036] The vibration damping structure can be suitably used for damping vibrations from tires by being provided between the suspension and body of an automobile, or for preventing vibrations from automobile panels and the like. [Example]

[0037] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples.

[0038] [Comparative Example 1] A hot-rolled steel plate (SS400) was used, and the shape shown in Figure 2 was measured. The length (L) was 300 mm, the width (W) was 50 mm, the length (L') from the thick end to the free end of the wedge-shaped part was 200 mm, the length (L") of the thin-walled part with a constant thickness was 10 mm, the thickness (T) of the free end (thin-walled part) was 0.2 mm, and the thickness (T') of the thick-walled part was 5 mm. The thickness change h(x) of the wedge-shaped part (from the thick end to the thin-walled end (L'-L")) was (4.8 / 190 2 )x 2 A wedge-shaped metal vibration-damping plate with a damping coefficient of +0.2 was fabricated and used as a vibration-damping structure.

[0039] <Evaluation> The vibration-damping structures of the above-mentioned comparative example and example were freely supported by being hung from a support column with a rubber cord, with the tip of the wedge-shaped part facing downward, and an acceleration sensor (356A01 manufactured by PCB Co.) was attached 30 mm from the top end of the vibration-damping structure and 10 mm from the side end.

[0040] The area near the acceleration sensor was struck with an impulse hammer (PCB 086C03 (hard tip)), and the force of the impulse hammer (input) and the acceleration of the acceleration sensor (response) were input into an FFT analyzer (Siemens SCADAS III) where a Fourier transform was performed to obtain the acceleration / force transfer function (inertance). The strike was repeated five times and the inertance was measured by averaging the results. The evaluation results are shown in Figure 3.

[0041] Comparative Example 2 A magnetic sheet (damping plate made of iron oxide and chlorinated polyethylene) with a length (L''') of 10 mm, width (W) of 50 mm, thickness of 0.8 mm, and mass of 3.1 g was placed snugly on the tip of the wedge-shaped part of the wedge-shaped metal vibration damping plate of Comparative Example 1 so that its edge overlapped the free end, and the entire surface was attached with double-sided tape to create a vibration damping structure. The results of evaluation in the same manner as in Comparative Example 1 are shown in Figure 4.

[0042] Comparative Example 3 A vibration damping structure was fabricated in the same manner as in Comparative Example 2, except that the entire surface of a cold-rolled steel plate (SPCC) with a length (L''') of 10 mm, a width (W) of 50 mm, a thickness of 0.2 mm, and a mass of 1.6 g was soldered. The results of evaluation in the same manner as in Comparative Example 1 are shown in Figure 5.

[0043] [Example 1] A vibration damping structure was fabricated in the same manner as in Comparative Example 3, except that the cold-rolled steel plate (SPCC) of Comparative Example 3 was clamped and fastened at two points with turn clips. The results of evaluation in the same manner as in Comparative Example 1 are shown in FIG.

[0044] [Example 2] A vibration damping structure was fabricated in the same manner as in Comparative Example 3, except that the cold-rolled steel plate (SPCC) of Comparative Example 3 was clamped and fastened at two points with Gem Clips (registered trademark). The results of evaluation in the same manner as in Comparative Example 1 are shown in FIG.

[0045] Comparative Example 4 A vibration damping structure was fabricated by fastening bolts and nuts with a total mass of 5.0 g without providing a metal plate at the tip of the wedge-shaped portion of the wedge-shaped metal vibration damping plate of Comparative Example 1. The results of evaluation in the same manner as in Comparative Example 1 are shown in Figure 8.

[0046] [Example 3] A vibration damping structure was fabricated in the same manner as in Example 1, except that the free ends of the cold-rolled steel plate (SPCC) plate of Comparative Example 3 and the metal vibration damping plate were fastened with the same bolts and nuts as in Comparative Example 4. The results of evaluation in the same manner as in Comparative Example 1 are shown in FIG.

[0047] [Example 4] A vibration damping structure was fabricated in the same manner as in Example 2, except that the cold-rolled steel plate (SPCC) was replaced with an aluminum plate having a length (L''') of 10 mm, a width (W) of 50 mm, a thickness of 0.12 mm, and a mass of 3.4 g. The results of evaluation in the same manner as in Comparative Example 1 are shown in Figure 10.

[0048] Comparative Example 5 A stainless steel disk with a diameter (L) of 64 mm has a circular through-hole with a diameter of 17 mm at the center. The length (L') of the wedge-shaped part with the outer edge of the disk as the free end is 32 mm, the thickness (T) of the free end is 0.2 mm, and the thickness (T') of the thick part is 2 mm. The change in thickness of the wedge-shaped part, h(x), is (1.8 / 32 2 )x 2A disk-shaped metal vibration-damping plate with a vibration damping coefficient of +0.2 was fabricated and used as a vibration-damping structure. The results of evaluation in the same manner as in Comparative Example 1 are shown in FIG.

[0049] Comparative Example 6 A damping plate made of natural rubber with an inner diameter of 44 mm, an outer diameter of 64 mm, a thickness of 0.8 mm, and a mass of 4.0 g was placed snugly on the outer periphery of the wedge-shaped portion of the disk-shaped metal damping plate of Comparative Example 5, with its outer edge overlapping the free end of the disk-shaped metal damping plate, and the plate was then clamped in place at two points with Gem Clips (registered trademark), to create a damping structure. The results of evaluation in the same manner as in Comparative Example 1 are shown in Figure 13.

[0050] [Example 5] A damping plate made of cold-rolled steel (SPCC) with an inner diameter of 44 mm, an outer diameter of 64 mm, a thickness of 0.2 mm, and a mass of 2.6 g was placed snugly on the outer periphery of the wedge-shaped portion of the disk-shaped metal damping plate of Comparative Example 5 so that its outer edge overlapped the free end of the disk-shaped metal damping plate, and the plate was clamped in two places with Gem Clips (registered trademark) to create a damping structure. The results of evaluation in the same way as in Comparative Example 1 are shown in Figure 14.

[0051] Comparative Example 7 A hot-rolled steel plate (SS400) was used, and a square with sides of 130 mm had a circular through-hole with a diameter of 14 mm at the center. The through-hole was the free end of a wedge-shaped portion with an outer diameter of 97 mm. The thickness of the free end was 0.23 mm, and the thickness of the thick portion was 4.5 mm. The change in thickness of the wedge-shaped portion, h(x), was calculated as follows: (4.27 / 41.5 2 )x 2 A cone-shaped metal vibration-damping plate with a value of +0.14 was fabricated and used as a vibration-damping structure. The results of evaluation in the same manner as in Comparative Example 1 are shown in FIG.

[0052] [Comparative Example 8] A damping plate made of natural rubber with an inner diameter of 14 mm, an outer diameter of 34 mm, a thickness of 0.8 mm, and a mass of 1.3 g was placed snugly on the tip of the wedge-shaped part of the cone-shaped metal damping plate of Comparative Example 7 so that its inner edge overlapped the free end of the cone-shaped metal damping plate, and the plate was then clamped in two places with Gem Clips (registered trademark) to create a damping structure. The results of evaluation in the same way as in Comparative Example 1 are shown in Figure 17.

[0053] [Example 6] A damping plate made of cold-rolled steel (SPCC) with an inner diameter of 14 mm, an outer diameter of 34 mm, a thickness of 0.2 mm, and a mass of 1.16 g was placed snugly on the tip of the wedge-shaped part of the cone-shaped metal damping plate of Comparative Example 7 so that its inner edge overlapped the free end of the cone-shaped metal damping plate, and the plate was then clamped in place at two points with Gem Clips (registered trademark) to create a damping structure. The results of evaluation in the same way as in Comparative Example 1 are shown in Figure 18.

[0054] The results of Comparative Examples 1 and 2 show that vibrations can be damped by attaching a magnetic sheet.

[0055] The results of Examples 1 and 2 and Comparative Example 3 show that vibrations can be damped by friction between the metal plate and the metal vibration-damping plate, and the difference with Comparative Example 2 shows that by arranging the metal plate in a frictional manner, it can achieve the same or greater vibration-damping effect, despite being lighter than the magnetic sheet, which is an elastic material.

[0056] The vibration damping effect of Example 3 was lower than that of Examples 1 and 2, but this is thought to be because the friction of the metal plates was more limited than in Examples 1 and 2 due to bolt fastening. Furthermore, the vibration damping effect of Example 4 was lower than that of Example 1, but this is thought to be because the mass of the aluminum plate was lighter than that of the cold-rolled steel plate.

[0057] From the results of Example 5 and Comparative Examples 5 and 6, it can be seen that the disk-shaped metal vibration damping plate also exhibits a vibration damping effect by providing a metal plate that can be rubbed.

[0058] The results of Example 6 and Comparative Examples 7 and 8 show that the mortar-shaped metal vibration damping plate also exhibits vibration damping effects by providing a metal plate that can be rubbed. [Explanation of symbols]

[0059] 1 Metal vibration damping plate 11 Wedge-shaped part 12 Free end 13 Thick wall part 2 metal plate

Claims

1. A vibration damping structure comprising a metal vibration damping plate having at least a wedge-shaped portion and a metal plate abutting against a free end tip of the metal vibration damping plate, The thickness of the wedge-shaped portion changes to satisfy the following formula (1), A vibration-damping structure characterized in that the metal plate is provided so as to be able to frictionally contact the metal vibration-damping plate. h(x) = ε・x ｎ + h ０ ... Equation (1) However, in formula (1), x: Distance from the thin end of the wedge (mm) h(x): Plate thickness at distance x from the thin end of the wedge (mm) h ０ : Plate thickness of the thin end of the wedge-shaped part (mm) ε: positive constant n: real number greater than or equal to 1

2. 2. The vibration damping structure according to claim 1, wherein the metal vibration damping plate and the metal plate are sandwiched by a metallic elastic member.

3. 2. The vibration damping structure according to claim 1, wherein the metal vibration damping plate and the metal plate are fastened together by a metallic fastening member.

4. the metal vibration damping plate further includes a thin-walled portion having a constant plate thickness at a thin-walled end of the wedge-shaped portion, The thickness of the thin-walled portion is the same as the thickness of the thin-walled end of the wedge-shaped portion, 4. The vibration damping structure according to claim 1, wherein the metal plate is provided on the thin portion.

5. 5. The vibration damping structure according to claim 1, wherein the natural potential of the metal plate is equal to or lower than the natural potential of the metal vibration damping plate.

6. A vehicle equipped with a vibration damping structure, An automobile, wherein the vibration damping structure is the vibration damping structure according to any one of claims 1 to 5.

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