Dynamic Damper

Abstract

To provide a dynamic damper capable of relatively and optionally adjusting a horizontal resonance frequency to a vertical resonance frequency according to a requirement specification.SOLUTION: A dynamic damper 11 includes an outside fitting 13 including both side walls 16, 17 fixed to an upper face 12a of a base plate 12 mounted to a vibration source, a mass member 14 arranged inside the outside fitting, and four rubber elastic bodies 19a, 20b paired on each of the right and left sides and provided between both inside faces of both side walls and both outside faces of the mass member. The four elastic bodies are wholly formed in X-shaped inclination in front view so that the horizontal resonance frequency to the vertical resonance frequency of the vibration source can be relatively adjusted by adjusting an inclination angle θ of each elastic body.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a dynamic damper that is attached to a vibration source, such as the body of an automobile, to attenuate vibrations of a specific frequency. [Background technology]

[0002] A known conventional dynamic damper is described in the following Patent Document 1. Fig. 6 is a front view showing a conventional dynamic damper.

[0003] As shown in FIG. 6, this dynamic damper 1 comprises a gate-shaped outer metal fitting 2 that is attached to a vibration source such as a member of an automobile body, a mass member 5 that is placed inside the outer metal fitting 2 and is surrounded by a pair of side walls 3, 3 and an upper end wall 4 that connects the upper ends of the both side walls 3, 3, and a pair of left and right rubber elastic bodies 6, 6 that are vulcanized and bonded between the both outer surfaces of the mass member 5 and the opposing inner surfaces of the both side walls 3, 3.

[0004] In addition, the outer metal fitting 2 is fixed to a vibrating member 8, such as a member constituting the vehicle body, by fixing bolts 7, 7 that are inserted through mounting holes provided in a pair of fixing bracket pieces 3a, 3a that are integrally formed at the lower ends of both side walls 3, 3.

[0005] In addition, a through hole 4a is formed in the center of the upper end wall 4, and an engaging protrusion 9 made of rubber material is provided on the upper surface of the mass member 5, protruding upward from the through hole 4a.Even if the rubber elastic bodies 6, 6 break and the mass member 5 falls, the engaging protrusion 9 will catch on the through hole 4a between the outer metal fitting 2 and the vibration member 8, preventing the mass member 5 from falling off.

[0006] This dynamic damper 1 is used to reduce vibrations of a vibrating member 8, such as a member of the vehicle body, in the vertical direction of the vehicle (X direction in the figure), and is set to a desired resonance frequency (Hz) by tuning the spring constant of the rubber elastic bodies 6, 6 and the mass of the mass member 5. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2004-353826 A (Fig. 1) Summary of the Invention [Problem to be solved by the invention]

[0008] However, in the dynamic damper 1 described in Patent Document 1, the rubber elastic bodies 6, 6 are arranged linearly in the horizontal direction (Y direction in the figure) relative to the mass member 5, so when the mass of the rubber elastic bodies 6, 6 and the mass member 5 is tuned to a desired resonant frequency in the vertical direction (X direction), the resonant frequency in the Y direction is fixed to a constant resonant frequency corresponding to the resonant frequency in the X direction. In other words, the resonant frequency in the Y direction is determined depending on the resonant frequency in the X direction, and it is not possible to set the resonant frequencies in the X and Y directions relative to each other.

[0009] In other words, because the conventional rubber elastic bodies 6, 6 are arranged linearly in the Y direction relative to the mass member 5, a pure shear force acts in the X direction while a linear pure compressive force acts in the Y direction, which may cause the resonance frequency in the Y direction to be, for example, about 2 to 2.5 times higher than the resonance frequency in the X direction. As a result, it may become impossible to set the resonance frequency in the Y direction low, and the tuning range may also become smaller.

[0010] The present invention was devised in consideration of the technical problems with the conventional dynamic dampers described above, and provides a dynamic damper in which the left-right resonance frequency can be adjusted arbitrarily and relatively to the up-down resonance frequency by adjusting the inclination angle of each pair of left and right elastic bodies provided between the outer member and the mass member. [Means for solving the problem]

[0011] The invention according to claim 1 of the present application is an apparatus comprising: an outer member made of a metal material attached to a vibration source and having a pair of left and right side walls and end walls provided between ends of the both side walls in the longitudinal direction; a mass member arranged inside the outer member; and four elastic bodies arranged vertically and horizontally with a certain gap between them, the elastic bodies being provided between the inner surfaces of the both side walls of the outer member and the outer surfaces of the mass member facing the both inner surfaces, The four elastic bodies are each formed at an angle from the inner surfaces of both side walls of the outer member toward the outer surfaces of the mass member, and by adjusting the angle of inclination of each elastic body, the left-right resonance frequency of the vibration source can be adjusted relative to the up-down resonance frequency. [Effects of the Invention]

[0012] According to the present invention, by adjusting the inclination angle of each elastic body, it is possible to adjust the left-right resonance frequency relative to the up-down resonance frequency and arbitrarily, thereby making it possible to damp the desired up-down and left-right resonance frequencies according to the required specifications of the dynamic damper. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a plan view showing a first embodiment of a dynamic damper according to the present invention. [Figure 2] FIG. 2 is a cross-sectional view taken along line AA in FIG. [Figure 3] FIG. 4 is a characteristic diagram showing the relationship between the Y / X resonance frequency ratio of the dynamic damper and the inclination angle of each elastic body in the first embodiment. [Figure 4] FIG. 4 is a plan view showing a second embodiment of the dynamic damper of the present invention. [Figure 5] FIG. [Figure 6] FIG. 1 is a front view showing a conventional dynamic damper. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, various embodiments of the dynamic damper according to the present invention will be described with reference to the drawings. In these embodiments, the dynamic damper is attached to the front suspension member of an automobile. Fig. 1 is a plan view showing a first embodiment of the dynamic damper according to the present invention, and Fig. 2 is a cross-sectional view taken along line AA in Fig. 1.

[0015] The front suspension member (not shown), which is a source of vibration in an automobile, is well known for suppressing twisting of the vehicle body while driving, absorbing shocks from the road surface, and improving ride comfort and handling stability, and is made up of a square frame formed from highly rigid hot-rolled steel plates for welded structures, etc. In addition to the front suspension, this front suspension member also supports the engine, steering, etc.

[0016] As shown in FIG. 2, the dynamic damper 11 is disposed so that its up-down direction (arrow X direction) substantially coincides with the up-down direction of the vehicle body, and its left-right direction (arrow Y direction) substantially coincides with the width direction of the vehicle body.

[0017] As shown in Figures 1 and 2, this dynamic damper 11 comprises a base plate 12 fixed to the frame of the front suspension member, which is the vibration source (vibration member), by two bolts not shown in the figures, an outer metal fitting 13, which is a gate-shaped outer member fixed to the upper surface 12a of this base plate 12 by welding, a mass member 14, which is a mass member, arranged inside this outer metal fitting 13, and a total of four rubber elastic bodies 19a, 19b, 20a, 20b, each paired on the top, bottom, left, and right, arranged between the outer metal fitting 13 and the mass member 14.

[0018] The base plate 12 is made of a metal plate and formed into a rectangular shape that is long in the horizontal direction in the figure, with its lower surface abutting against a predetermined upper surface of the frame of the front suspension member, and two bolt insertion holes 12b, 12b, into which the two bolts are inserted, are formed in the vertical direction at both ends in the longitudinal direction.

[0019] The outer metal fitting 13 is formed by bending a long, narrow metal plate into a U-shape and has rectangular side walls 16, 17 and an upper wall 18 provided between the upper longitudinal edges of the side walls 16, 17. The side walls 16, 17 are formed like vertical flat plates with their inner surfaces 16a, 17a facing each other and their lower edges 16b, 17b welded to the upper surface 12a of the base plate 12 by, for example, arc welding. Welds 21, 22 are located on the inside of the lower edges 16b, 17b, respectively.

[0020] The upper end wall 18 is formed in the shape of a horizontal flat plate, and a holding hole 24 that constitutes part of a fall prevention mechanism 23 (described later) is formed through the wall in the vertical direction at the center position in the longitudinal direction.

[0021] 2, the mass member 14 is formed in a substantially cubic shape of a predetermined mass, with both outer side surfaces 14a, 14b disposed laterally facing the inner side surfaces 16a, 17a of both side walls 16, 17 of the outer metal fitting 13, and with a bottom surface 14c disposed a predetermined distance S away from the top surface 12a of the base plate 12. Furthermore, the top surface 14d of the mass member 14 is disposed a predetermined distance away from the bottom surface of the upper end wall 18 via a retaining bolt 25 of a fall prevention mechanism 23, which will be described later. Furthermore, a female threaded hole 14e is formed in the center of the top surface 14d of the mass member 14 along the vertical direction, into which the male threaded portion 25c of the shaft portion 25b of the retaining bolt 25 is threadedly fitted.

[0022] The four elastic bodies 19a to 20b have their outer axial ends vulcanized and bonded to the opposing inner surfaces 16a, 17a of the both side walls 16, 17, and their inner axial ends vulcanized and bonded to both outer surfaces 14a, 14b of the mass member 14.

[0023] The elastic bodies 19a-20b are inclined from the inner surfaces 16a, 17a of the side walls 16, 17 of the outer metal fitting 13 toward the outer surfaces 14a, 14b of the mass member 14, and are arranged at positions symmetrical in the vertical and left directions about the center line P of the mass member 14 in the width direction and the center line P1 in the vertical direction. That is, in Figure 2, the pair of upper and lower elastic bodies 19a, 19b on the left side and the pair of upper and lower elastic bodies 20a, 20b on the right side are inclined from their outer ends in the axial direction toward their inner ends toward the center of gravity GP of the mass member 14, and are arranged as a whole in an X shape when viewed from the front, and are arranged at positions symmetrical in the vertical and left directions about the center line P of the mass member 14 in the width direction and the center line P1 in the vertical direction.

[0024] 2, the elastic bodies 19a to 20b are arranged so that the central position OP of the arrangement of the four elastic bodies 19a to 20b at the intersection of the center lines P and P1 of the mass member 14 coincides with the center of gravity GP of the mass member 14. Note that the term "matching" here refers to a concept that includes cases where the center of gravity GP and the central position OP coincide perfectly, as well as cases where they are close to but not perfectly coincident.

[0025] Furthermore, the inclination angle θ of each of the elastic bodies 19a to 20b relative to the horizontal direction is set within a range of approximately 20° to 70°. The inclination angle θ of each of the elastic bodies 19a to 20b is determined in accordance with the ratio of the resonance frequencies (Hz) in the vertical direction (X direction) and the horizontal direction (Y direction) required for the dynamic damper 11.

[0026] In this way, in the present invention, the inclination angle θ of each of the elastic bodies 19a to 20b is set to approximately 20° to 70°, which was determined by the inventors by conducting an analytical experiment on the relationship between the Y / X resonance frequency ratio and the inclination angle θ shown in Fig. 3. In this analytical experiment, as shown in Fig. 3, the inclination angle θ (°) of the elastic bodies 19a to 20b is shown as a horizontal line, and the resonance frequency ratio in the left-right Y direction / up-down X direction is shown as a vertical line.

[0027] This analytical experiment revealed that the Y / X resonance frequency ratio changes depending on the inclination angle θ of each elastic body 19a-20b. When the inclination angle θ is set to 0°, that is, when the elastic bodies are set in a straight line in the horizontal direction as in the prior art described in the publication, the Y / X resonance frequency ratio becomes 2.0 to 2.5 times, or more than 1.80 times. Furthermore, when the inclination angle θ is gradually increased, for example, to about 80° or more, the Y / X resonance frequency ratio becomes approximately 1.00 times or less, which is sufficiently small.

[0028] In the normal required specifications for the dynamic damper 11 in the front suspension member of the vehicle body, the Y / X resonance frequency ratio is 1.70 to 1.20, so in the present invention, the tilt angle θ that satisfies the Y / X resonance frequency ratio is set between 20° and 70°. In this embodiment, the tilt angle θ is set to approximately 35° to 50° to further narrow the required Y / X resonance frequency ratio to approximately 1.55 to 1.40, and can be arbitrarily adjusted according to the required specifications of the dynamic damper 11.

[0029] A fall prevention mechanism 23 for the mass member 14 is provided between the upper end wall 18 and the mass member 14. This fall prevention mechanism 23 has a retaining hole 24 formed in the upper end wall 18, penetrating the wall in the vertical direction, approximately at the center thereof, and a retaining bolt 25, which is a fall prevention member that can be held by the edge of the retaining hole 24.

[0030] The retaining hole 24 has a predetermined inner diameter d, which is smaller than the outer diameter d1 of a head portion 25a of the retaining bolt 25, which will be described later.

[0031] The retaining bolt 25 has a substantially hexagonal head 25a and a shank 25b that is integrally formed below the head 25a, inserted into the retaining hole 24, and fixed to the upper end of the mass member 14. The head 25a is positioned above the retaining hole 24, and as described above, its outer diameter d1 is larger than the inner diameter d of the retaining hole 24 so that, if the mass member 14 is accidentally dropped, the outer periphery of the lower end surface will catch on the edge of the retaining hole 24. The shank 25b has a large diameter portion on the head 25a side that is inserted into the retaining hole 24, and a male thread portion 25c is formed on the outer periphery of the stepped, smaller diameter tip portion that is located below the large diameter portion.

[0032] Furthermore, when the male threaded portion 25c of the retaining bolt 25 is screwed and fixed into the female threaded hole 14e of the mass member 14, the distance S1 between the underside of the head 25a and the upper surface of the upper end wall 18 is set to be smaller than the distance S between the upper surface of the base plate 12 and the lower surface of the mass member 14. [Actions and Effects of the Dynamic Damper in the Present Embodiment] According to the dynamic damper 11 of this embodiment having the above-described configuration, by adjusting the inclination angle θ of each elastic body 19a to 20b, it is possible to adjust the resonant frequency in the left-right direction (Y direction) relative to the resonant frequency in the up-down direction (X direction), and therefore it is possible to damp the resonant frequencies in the up-down and left-right directions according to the required specifications of the dynamic damper 11.

[0033] In this embodiment, by adjusting the inclination angle θ of each of the elastic bodies 19a to 20b to within a range of, for example, approximately 35° to 50°, it is possible to further narrow the required Y / X resonance frequency ratio to approximately 1.55 to 1.40.

[0034] In this way, it is possible to lower the resonance frequency in the Y direction relative to the resonance frequency in the X direction, and to widen the tuning range, thereby achieving an excellent vibration damping effect according to the object and direction of attachment of the dynamic damper 11.

[0035] Furthermore, according to this embodiment, by aligning the central position OP of the arrangement of the four elastic bodies 19a-20b with the center of gravity GP of the mass member 14, the translational movement of the mass member 14 that occurs together with the center of gravity GP due to resonance is not affected by the rotational movement about the center of gravity GP. This makes it possible to suppress the mass effect of the mass member 14, i.e., the reduction in the damping effect due to the mass. As a result, the resonance suppression effect of the mass member 14 in the vertical and horizontal directions is enhanced.

[0036] In other words, if the central position OP of the arrangement of the four elastic bodies 19a to 20b is displaced, for example, vertically from the center of gravity GP of the mass member 14, a rotational motion occurs along with the translational motion, which may reduce the damping effect of the mass member 14. However, in this embodiment, the central position OP of the arrangement of the elastic bodies 19a to 20b is aligned with the center of gravity GP of the mass member 14, thereby suppressing the occurrence of the rotational motion, thereby enhancing the resonance suppression effect of the mass member 14.

[0037] Furthermore, because the lower edges 16b, 17b of both side walls 16, 17 of the outer metal fitting 13 are welded to the upper surface 12a of the base plate 12, the support force for both side walls 16, 17, that is, the support force for both side walls 16, 17 against lateral vibration is particularly increased. Therefore, lateral vibration of the outer metal fitting 13 is suppressed, and the lateral vibration damping effect of the dynamic damper 11 is increased.

[0038] 2, in the fall prevention mechanism 23 of this embodiment, when the male threaded portion 25c of the retaining bolt 25 is threadedly fixed into the female threaded hole 14e of the mass member 14, the head 25a is positioned above the retaining hole 24 via the large diameter portion of the shaft 25b. However, if each elastic body 15 breaks due to deterioration over time or the like and the mass member 14 falls, the underside of the head 25a catches on the edge of the retaining hole 24, and the mass member 14 is suspended from the upper end wall 18 via the retaining bolt 25 and the retaining hole 24, and does not interfere with the upper surface 12a of the base plate 12.

[0039] Furthermore, the fall prevention mechanism 23 has a simple structure, being simply constituted by the retaining hole 24 and the retaining bolt 25, which simplifies manufacturing and prevents costs from rising. Second Embodiment of the Present Invention A second embodiment of the present invention will now be described. Figure 4 is a plan view showing a dynamic damper according to a second embodiment of the present invention, and Figure 5 is a front view of the second embodiment.

[0040] As shown in Figures 4 and 5, the dynamic damper 11 of this second embodiment comprises a base plate 12 fixed to the frame of a front suspension member by three bolts (not shown), a gate-shaped outer metal fitting 13 positioned approximately in the center of the upper surface 12a of the base plate 12 and having a pair of left and right side walls 16 and 17, an inner metal fitting 27 which is an inner member positioned inside the outer metal fitting 13, a mass member 14 positioned inside the inner metal fitting 27, a plurality of rubber elastic bodies 19a to 20b (four, upper and lower in this embodiment) vulcanized and bonded between the inner surfaces 16a, 17a of the side walls 16, 17 of the outer metal fitting 13 and the outer surfaces of the side pieces 27b, 27c of the inner metal fitting 27, and four fastening bolts 28 which are connecting members that fix the mass member 14 to the inner metal fitting 27.

[0041] The base plate 12 is made of a metal plate and has an irregular V-shape in plan view, and has three bolt insertion holes 12b formed at both ends and the center in FIG. 4 through which the three bolts are inserted.

[0042] The outer metal fitting 13, like that of the first embodiment, is formed by bending a metal plate into a substantially U-shape, and has left and right side walls 16, 17 and an upper end wall 18 connecting the upper edges of the side walls 16, 17. The side walls 16, 17 are formed to be longer in the vertical direction than those of the first embodiment, and the other side wall 17 on the right side in Figure 5 has an upper end 18a formed in an inclined concave shape to avoid interference with other components.

[0043] Like the outer metal fitting 13, the inner metal fitting 27 is made by bending a metal plate into an inverted U-shape, and has a bottom wall piece 27a and side pieces 27b, 27c that stand upright from both longitudinal side edges of the bottom wall piece 27a and are arranged opposite the left and right side walls 16, 17. The inner metal fitting 27 is formed so that the thickness t1 of the plate material is thinner than the thickness t of the outer metal fitting 13, and the side pieces 27b, 27c are arranged parallel to the both side walls 16, 17 of the outer metal fitting 13 with a predetermined gap between them.

[0044] The bottom wall piece 27a is formed horizontally in parallel with the base plate 12, and a gap of a predetermined distance S is formed between the lower surface and the upper surface of the base plate 12.

[0045] The side pieces 27b, 27c each have an insertion hole (not shown) formed through the upper end thereof, into which a small-diameter male screw portion at the tip of the shaft portion of each fastening bolt 28 (described later) is inserted.

[0046] Mass member 14 is formed, for example, from an iron-based metal material into a generally rectangular parallelepiped that is long in the vertical direction, with length L in the vertical direction (X direction) greater than length L1 in the horizontal direction (Y direction), and is housed and disposed inside inner metal fitting 27. Furthermore, both sides of the upper end of mass member 14 are fixed to both side pieces 27b, 27c of inner metal fitting 27 by four fastening bolts 28.

[0047] As shown in Figures 4 and 5, the four elastic bodies 19a to 20b are each formed in a cylindrical shape, and each outer end and each inner end in the axial direction are vulcanization bonded to each inner surface 16a, 17a of each side wall 16, 17 of the outer metal fitting 13 and each outer surface of each side piece 27b, 27c of the inner metal fitting 27.

[0048] As shown in FIG. 5, each pair of left and right elastic bodies 19a-20b is inclined from the inner surfaces 16a, 17a of the side walls 16, 17 of the outer metal fitting 13 toward the outer surfaces of the side pieces 27b, 27c of the inner metal fitting 27, forming a diamond shape as a whole when viewed from the front of FIG. 5. That is, the pair of upper and lower elastic bodies 19a, 19b on the left side and the pair of upper and lower elastic bodies 20a, 20b on the right side in FIG. 5 are inclined from their respective axial outer ends toward their respective inner ends on the side pieces 27b, 27 of the inner metal fitting 27, vertically separating them from each other, forming a diamond shape as a whole when viewed from the front. Furthermore, as in the first embodiment, each elastic body 19a-20b is arranged symmetrically in the vertical direction with respect to the widthwise center line P and the vertical center line P1 of the mass member 14. Therefore, the center position OP of the arrangement of the four elastic bodies 19a-20b coincides with the center of gravity GP of the mass member 14.

[0049] Furthermore, the inclination angle θ of each elastic body 19a-20b is set between 20° and 70° in the present invention because the normal required specifications for the dynamic damper 11 basically require a Y / X resonance frequency ratio of 1.70 to 1.20. However, in this embodiment, as in the first embodiment, the inclination angle θ is set to approximately 35° to 50° in order to achieve a Y / X resonance frequency ratio of approximately 1.55 to 1.40 in the required specifications for the dynamic damper 11.

[0050] Furthermore, the fall prevention mechanism 23 is the same as that in each embodiment, so it is given the same reference numeral and a detailed description thereof will be omitted.

[0051] As described above, in the dynamic damper 11 of the second embodiment, the elastic bodies 19a-20b are formed not horizontally but at an angle, as in the first embodiment. By adjusting the angle θ of inclination, it is possible to arbitrarily adjust the resonant frequency in the left-right direction (Y direction) relative to the resonant frequency in the up-down direction (X direction). This makes it possible to damp the resonant frequencies in the up-down and left-right directions according to the required specifications of the dynamic damper 11. In particular, it is possible to lower the resonant frequency in the Y direction relative to the resonant frequency in the X direction, and the tuning range can be expanded. As a result, an excellent vibration damping effect can be obtained according to the object to which the dynamic damper 11 is attached and the attachment direction.

[0052] Furthermore, in this second embodiment, the center position OP of the arrangement of the elastic bodies 19a-20b coincides with the center of gravity GP of the mass member 14, so that, as in the first embodiment, the translational movement of the mass member 14 that occurs together with the center of gravity GP due to resonance is not affected by the rotational movement about the center of gravity GP. This makes it possible to suppress the mass effect of the mass member 14, i.e., the reduction in the damping effect due to the mass. As a result, the resonance suppression effect of the mass member 14 in the vertical and horizontal directions is enhanced.

[0053] Furthermore, in the second embodiment, unlike the first embodiment, the inner metal fitting 27 is provided, and therefore the vibration source can be set to a specific fixed frequency for a different target.

[0054] Furthermore, the fall prevention mechanism 23 prevents the mass member 14 from falling accidentally, as in the first embodiment.

[0055] The present invention is not limited to the configurations of the above-described embodiments, and it is possible to further modify, for example, the shape of the outer metal member 13 and the shape of the mass member 5. Furthermore, the outer diameter, length, and inclination angle θ of each of the elastic bodies 19a to 20b can be modified as desired depending on the object to which the dynamic damper 11 is attached, that is, the natural frequency of the vibration to be reduced.

[0056] In addition, the dynamic damper can also be applied to other vibrating components of a vehicle body or to vibrating components of ships other than automobiles, and the mounting position relative to the vibrating component can be set arbitrarily. [Explanation of symbols]

[0057] 11...Dynamic Damper 12...Base plate 13...Outer metal fittings (outer member) 14...Mass member 14a·14b…Both outer surfaces 16...One side wall 16a…Inner surface 17...Other side wall 17a…Inner surface 18…Top end wall 19a, 19b, 20a, 20b...Elastic body 23…Fall prevention mechanism 25...volts 27...Inner metal fittings (inner components) 27a...Bottom wall piece 27b・27c...both sides θ: Inclination angle of elastic body GP: Center of gravity of mass member OP: Center position of each elastic body P: Center line of mass member in width direction P1: Center line of the mass member in the vertical direction

Claims

1. the vibration source is attached to a vibration source and comprises an outer member made of a metal material having a pair of left and right side walls and end walls provided between longitudinal ends of the both side walls; a mass member arranged inside the outer member; and four elastic bodies arranged vertically and horizontally between the inner surfaces of the both side walls of the outer member and the outer surfaces of the mass member facing the both inner surfaces, the elastic bodies being arranged with a certain gap between them in the vertical direction; a dynamic damper characterized in that the four elastic bodies are each formed at an angle from the inner surfaces of both side walls of the outer member toward the outer surfaces of the mass member, and that the left-right resonance frequency of the vibration source can be adjusted relatively to the up-down resonance frequency by adjusting the angle of inclination of each elastic body.

2. 2. The dynamic damper according to claim 1, A dynamic damper characterized in that the inclination angles of the four elastic bodies are set to 20° to 70°, respectively, so that the resonance frequency in the left-right direction is 1.2 to 1.7 times the resonance frequency in the up-down direction.

3. 2. The dynamic damper according to claim 1, The four elastic bodies are arranged at an angle in an X-shape when viewed from the front, and are arranged in symmetrical positions in the vertical and left-right directions around the center line of the width direction and the center line of the up-down direction of the mass member, so that the center position of the arrangement of the four elastic bodies coincides with the center of gravity of the mass member.

4. an outer member made of a metal material attached to a vibration source and having a pair of left and right side walls and end walls provided between ends of the side walls in the longitudinal direction; an inner member made of a metal material arranged inside the outer member and having side pieces facing the side walls of the outer member; a mass member arranged inside the inner member; and four elastic bodies arranged vertically and at upper, lower, left and right positions with a certain gap between them, the elastic bodies being arranged between the inner surfaces of the side walls of the outer member and the outer surfaces of the side pieces of the inner member facing the inner surfaces, A dynamic damper characterized in that the four elastic bodies are each formed at an angle from the inner surfaces of both side walls of the outer member toward the outer surfaces of both side pieces of the inner member, and that by adjusting the angle of inclination of each elastic body, the left-right resonance frequency of the vibration source can be adjusted relatively to the up-down resonance frequency.

5. 5. The dynamic damper according to claim 4, A dynamic damper characterized in that the inclination angles of the four elastic bodies are set to 20° to 70°, respectively, so that the resonance frequency in the left-right direction is 1.2 to 1.7 times the resonance frequency in the up-down direction.

6. 6. The dynamic damper according to claim 5, The dynamic damper is characterized in that the four elastic bodies are arranged in a slanted diamond shape when viewed from the front, and are arranged symmetrically about the center line of the width direction and the center line of the length direction of the mass member, so that the center position of the arrangement of the four elastic bodies coincides with the center of gravity of the mass member.

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