Dynamic vibration absorber

Abstract

To provide a dynamic vibration absorber capable of appropriately attenuating the vibration of an object. 【Solution means】The dynamic vibration absorber has a curved surface that is curved in a concave shape and has at least one groove formed in the bending direction, and moves in accordance with the vibration of the object. The dynamic vibration absorber includes a moving part that rolls or slides on the curved surface, and a mass body that moves in the bending direction by the rolling or sliding of the moving part.

Description

Technical Field

[0001] The present invention relates to a dynamic vibration absorber.

Background Art

[0002] As a vibration damping device for damping the vibration of an object, for example, a dynamic vibration absorber as described in Patent Document 1 is known.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the dynamic vibration absorber as described above, it is required to appropriately damp the vibration of the object.

[0005] The present invention has been made in view of the above, and an object thereof is to provide a dynamic vibration absorber capable of appropriately damping the vibration of an object.

Means for Solving the Problems

[0006] The dynamic vibration absorber according to the present invention has a curved surface that is curved in a concave shape and has at least one groove portion formed in the bending direction, and moves in accordance with the vibration of the object, and a moving portion that rolls or slides on the curved surface, and includes a mass body that moves in the bending direction by the rolling or sliding of the moving portion.

Effects of the Invention

[0007] According to the present invention, it is possible to provide a dynamic vibration absorber capable of appropriately damping the vibration of an object.

Brief Description of the Drawings

[0008]

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MODE FOR CARRYING OUT THE INVENTION

[0009] Hereinafter, embodiments of the dynamic vibration absorber according to the present invention will be described with reference to the drawings. Note that the present invention is not limited by this embodiment. In addition, the constituent elements in the following embodiments include those that can be replaced by those skilled in the art and are easy, or those that are substantially the same.

[0010] FIG. 1 is a diagram schematically showing an example of the dynamic vibration absorber according to the present embodiment. The vertical direction in FIG. 1 indicates the vertical direction. The dynamic vibration absorber 100 shown in FIG. 1 is a synchronous mass type dynamic vibration absorber and is an example of a vibration damping device that attenuates the vibration of the object 30. As shown in FIG. 1, the dynamic vibration absorber 100 according to the present embodiment includes a mass body 10 and a curved surface 20.

[0011] The mass body 10 has a base portion 11 and a moving portion 12. The base portion 11 is, for example, in the shape of a rectangular parallelepiped. Note that the base portion 11 is not limited to the shape of a rectangular parallelepiped and may have other shapes.

[0012] The moving portion 12 is provided on the lower surface 11a of the base portion 11. The moving portion 12 is cylindrical or cylindrical. The moving portion 12 is formed using a metal such as iron, for example. The moving portion 12 is rotatably supported about an axis with respect to the base portion 11 by a bearing (not shown) about a central axis AX. In the present embodiment, for example, two moving portions 12 are provided. The two moving portions 12 are formed to have the same shape and the same dimensions, for example. One or three or more moving portions 12 may be provided.

[0013] The curved surface 20 is a surface on which the moving portion 12 of the mass body 10 rolls. The curved surface 20 is a concave curved surface. In the present embodiment, the curved surface 20 is a concave surface formed by a part of a cylindrical surface. Hereinafter, the direction in which the curved surface 20 curves is denoted as the bending direction D. In the present embodiment, the bending direction D is the circumferential direction (circumferential direction) of the cylindrical surface. The curved surface 20 is fixed to the object 30 to be vibrated. The curved surface 20 may be a part of the object 30. Alternatively, the curved surface 20 may be formed on a fixing member fixed to the object 30. Examples of the object 30 include structures such as machines and buildings. In the present embodiment, one curved surface 20 is provided for the two moving portions 12. That is, the two moving portions 12 roll on the common curved surface 20.

[0014] The curved surface 20 has a plurality of groove portions 21. The groove portions 21 are formed to extend, for example, in a direction intersecting the bending direction D. The groove portions 21 are formed so as to be located on the path along which the above-described moving portion 12 moves. The groove portions 21 are rectangular in cross-sectional view. The plurality of groove portions 21 are arranged at intervals in the circumferential direction of the curved surface 20. The intervals between the groove portions 21 adjacent to each other in the circumferential direction may all be equal, or at least a part thereof may be different. The plurality of groove portions 21 may be formed to all have the same shape and the same dimensions, for example, or at least one of them may be formed to have a different shape and different dimensions from the others.

[0015] The operation of the dynamic vibration absorber 100 described above will be explained. FIGS. 2 and 3 are diagrams showing an example of the operation of the dynamic vibration absorber 100. When the object 30 vibrates, the curved surface 20 vibrates integrally with the object 30 and moves in response to the vibration. Due to the movement of the curved surface 20, the moving part 12 disposed on the curved surface 20 rolls while rolling with respect to the curved surface 20, and the mass body 10 moves relatively with respect to the curved surface 20. The mass body 10 moves while obtaining a restoring force by the curved surface 20 curved in a cylindrical shape. The restoring force of the mass body 10 can be quantitatively controlled by adjusting the diameter of the curved surface 20.

[0016] When the mass body 10 moves relatively with respect to the curved surface 20, as shown in FIG. 2, the moving part 12 rolls while falling into the groove part 21. When the moving part 12 falls into the groove part 21, it collides with the wall part 21w disposed on the front side in the moving direction of the mass body 10 in the groove part 21. Due to this collision, the kinetic energy of the object 30 dissipates. By dissipating the kinetic energy of the object 30 in this way, the vibration of the object 30 is attenuated.

[0017] In addition, by adjusting the dimension and depth of the groove part 21 in the bending direction D, when the mass body 10 makes a relative movement with the curved surface 20, after the moving part 12 collides with the side wall of the groove part 21, it can roll over the groove part 21. That is, by adjusting the shape and dimension of the groove part 21 so that the moving part 12 does not fit in, the moving part 12 can be rolled over the groove part 21. Thereby, as shown in FIG. 3, a collision can be generated between the moving part 12 and a plurality of groove parts 21 provided on the curved surface 20 in the bending direction D.

[0018] The damping force function for damping the vibration of the object 30 can be controlled by three parameters: the drop amount of the mass body 10 determined by the radius of the moving part 20 and the width of the groove part 21 (dimension in the bending direction D), the coefficient of restitution of the moving part 20 with respect to the curved surface 21, and the pitch of the groove part 21 that determines the frequency of dropping. FIG. 4 is a diagram schematically showing an example of the operation in which the moving part 12 falls into the groove part 21. In FIG. 4, one moving part 12 and the groove part 21 are shown enlarged. Further, in FIG. 4, regarding the relative movement between the moving part 12 and the curved surface 20, the case where the position of the curved surface 20 is fixed and the moving part 12 moves with respect to the curved surface 20 will be described as an example. FIG. 4 shows the locus Q of the central axis AX when the moving part 12 moves with respect to the curved surface 20. In FIG. 4, let the radius of the moving part 12 be R and the width of the groove part 21 in the bending direction D be B. Further, in the state where the moving part 12 has fallen into the groove part 21, let the angle formed by the perpendicular line passing through the central axis AX and the line segment connecting the upper end part on the front side in the advancing direction of the bending direction D from the central axis AX in the groove part 21 be θ. Also, let the difference (drop amount) between the height position of the central axis AX of the moving part 12 when rolling on the curved surface 20 and the height position of the central axis AX of the moving part 12 in the state of having fallen into the groove part 21 be h.

[0019] In this case, the drop amount h is h = R(1 - cosθ) ≒ Rθ 2 / 2 and is shown by. Therefore, θ 2 = 2h / R ···(1) That is.

[0020] Also, the width B is B / 2 = R·sinθ ≒ R·θ and is shown by. Therefore, θ = B / 2R ···(2) That is.

[0021] From the above equations (1) and (2), h = B 2 / 8R ···(3) That is.

[0022] As shown in Fig. 4, when the moving part 12 of the mass body 10 collides with the wall part 21w, the energy loss ΔE of the object 30 is given by setting the mass of the mass body 10 as M, the coefficient of restitution between the moving part 12 and the wall part 21w as e, and the gravitational acceleration as g, ΔE = Mgh(1 - e) ··· (4) That is.

[0023] Here, from the above equations (3) and (4), ΔE = Mg(1 - e)B 2 / 8R It becomes.

[0024] Since a collision occurs once between the pitches d of the groove part 21, if it is assumed that the collision is caused by a constant resistance force F acting between the pitches d, F = Mg(1 - e)B 2 / (8Rd) It becomes.

[0025] Therefore, when the force received by the curved surface 20 (object 30) due to the collision is regarded as an equivalent frictional force, the coefficient of friction μ is μ = (1 - e)B 2 / (8Rd) It becomes. In this case, the vibration of the object 30 can be regarded as a non - linear vibration system. Note that on the curved surface 20, the coefficient of restitution e can be adjusted by appropriately selecting the material of the groove part 21.

[0026] As described above, the dynamic vibration absorber 100 according to the present embodiment has a curved surface 20 that is curved in a concave shape and at least one groove part 21 is formed along the bending direction, and moves in response to the vibration of the object 30, and a moving part 12 that rolls on the curved surface 20, and includes a mass body 10 that moves in the bending direction by the rolling of the moving part 12.

[0027] According to this configuration, when the object 30 vibrates, the curved surface 20 vibrates integrally with the object 30. Due to the vibration of the curved surface 20, the mass body 10 rolls the moving part 12 and moves relatively in the bending direction. During this relative movement, when the moving part 12 falls into the groove part 21, the wall part of the groove part 21 and the moving part 12 collide. Due to this collision, the kinetic energy of the curved surface 20 dissipates. By dissipating the kinetic energy of the curved surface 20, the vibration of the curved surface 20 and thus the vibration of the object 30 can be attenuated. Therefore, the vibration of the object 30 can be appropriately attenuated.

[0028] In the dynamic vibration absorber 100 according to the present embodiment, the curved surface 20 is provided on the object 30 so as to vibrate integrally with the object 30.

[0029] According to this configuration, when the moving part 12 falls into the groove part 21, the kinetic energy of the vibration of the object 30 can be directly dissipated.

[0030] In the dynamic vibration absorber 100 according to the present embodiment, the curved surface 20 is formed in a cylindrical shape.

[0031] According to this configuration, by forming the curved surface 20 in a cylindrical shape, the relative movement between the mass body 10 and the curved surface 20 can be performed smoothly.

[0032] In the dynamic vibration absorber 100 according to the present embodiment, a plurality of moving parts 12 are provided, and one curved surface 20 is provided for the plurality of moving parts 12.

[0033] According to this configuration, since a plurality of moving parts 12 are provided and one curved surface 20 is provided for the plurality of moving parts 12, the vibration of the object 30 can be appropriately attenuated while simplifying the configurations of the moving part 12 and the curved surface 20.

[0034] In the dynamic vibration absorber 100 according to the present embodiment, a plurality of groove parts 21 are provided, and the plurality of groove parts 21 are arranged at equal pitches in the bending direction.

[0035] According to this configuration, since the plurality of groove portions 21 are arranged at equal pitches in the bending direction, when the mass body 10 and the curved surface 20 move relative to each other, the dissipation of the collision energy can be performed at equal intervals.

[0036] In the vibration absorber 100 according to the present embodiment, the curved surface 20 is disposed below the moving portion 12 in the vertical direction.

[0037] According to this configuration, since the curved surface 20 is disposed below the moving portion 12, by dropping the moving portion 12 into the groove portion 21, a collision between the moving portion 12 and the groove portion 21 can be generated.

[0038] FIG. 5 is a diagram schematically showing the configuration of a vibration absorber 200 according to another example. The vibration absorber 200 shown in FIG. 5 includes a mass body 110 and a curved surface 120. The mass body 110 has a base portion 111 and a moving portion 112. The moving portion 112 is supported by the base portion 111 so as to be rotatable about a central axis AX along a horizontal plane.

[0039] The vibration absorber 200 according to the present embodiment has a configuration in which the curved surface 120 is provided for each moving portion 112. In the example shown in FIG. 5, for the moving portion 112A on the left side in the left-right direction in the figure, the curved surface 120A is provided, and for the moving portion 112B on the right side, the curved surface 120B is provided. The curved surfaces 120A and 120B are provided on the object 130 so as to vibrate integrally with the object 130.

[0040] The configurations of the curved surfaces 120A and 120B are the same as those of the above-described curved surface 20. That is, the curved surfaces 120A and 120B are curved concave downward and have a plurality of groove portions 121 in the bending direction D.

[0041] In the dynamic vibration absorber 200, as the object 130 vibrates, the curved surfaces 120A and 120B vibrate integrally with the object 130 and move in response to the vibration. Due to the movement of the curved surfaces 120A and 120B, the moving parts 112A and 112B disposed on the curved surfaces 120A and 120B roll on the curved surfaces 120A and 120A, while the mass body 110 moves relatively to the curved surfaces 120A and 120B. In this relative movement, the moving parts 112A and 112B collide with the groove parts 121 of the curved surfaces 120A and 120B, and the kinetic energy of the curved surfaces 120A and 120B is dissipated. Due to the dissipation of this kinetic energy, the vibration of the curved surfaces 120A and 120B, and thus the vibration of the object 130, is attenuated.

[0042] As described above, in the dynamic vibration absorber 200 according to the present embodiment, a plurality of moving parts 112 are provided (moving parts 112A and 112B), and one or more curved surfaces 120 are provided for each moving part 112 (curved surfaces 120A and 120B). According to this configuration, since the curved surfaces 120A and 120B are provided for each of the plurality of moving parts 112A and 112B, the kinetic energy can be dissipated for each of the moving parts 112A and 112B, and the attenuation of the object 130 can be surely performed.

[0043] FIG. 6 is a diagram schematically showing the configuration of a dynamic vibration absorber 300 according to another example. The dynamic vibration absorber 300 shown in FIG. 6 includes a mass body 210 and curved surfaces 220. The mass body 210 has a base part 211 and a moving part 212. In the example shown in FIG. 6, the base part 211 and the moving part 212 are provided separately. Specifically, the base part 211 is placed on the moving part 212. The configuration of the curved surfaces 220A and 220B is the same as that of the above-described curved surface 20. That is, the curved surfaces 220A and 220B are provided on the object 230 so as to vibrate integrally with the object 230, are curved in a concave shape downward, and have a plurality of groove parts 221 in the bending direction D.

[0044] Further, on the base 211, a curved surface 213 is provided at a portion in contact with the moving part 212. The curved surface 213 is curved so as to be concave upward, and a plurality of groove portions 214 are provided in the bending direction. In the example shown in FIG. 6, the curved surface 213 and the groove portion 214 are the same as, for example, a configuration in which the curved surface 220 and the groove portion 221 are vertically symmetric. That is, in the dynamic vibration absorber 300, curved surfaces (curved surface 213, curved surface 220) are provided on both sides in the vertical direction of the moving part 212, and groove portions 214 and 221 are provided on the curved surfaces 213 and 220 on both sides in the vertical direction, respectively.

[0045] Further, a configuration is provided in which the curved surfaces 213 and 220 are provided for each moving part 212. That is, for the moving part 212A on the left side in the left-right direction in the figure, the curved surfaces 213A and 220A are provided, and for the moving part 212B on the right side, the curved surfaces 213B and 220B are provided.

[0046] FIG. 7 is a diagram showing an example of the operation of the dynamic vibration absorber 300. As shown in FIG. 7, in the dynamic vibration absorber 300, when the object 230 vibrates, the curved surface 220 vibrates integrally with the object 230 and moves according to the vibration. Due to the movement of the curved surface 220, the moving part 212 disposed on the curved surface 220 rolls with respect to the curved surface 220. Further, when the rolling of the moving part 212 is transmitted to the base 211 via the curved surface 213, the base 211 moves relative to the moving part 212. The moving direction of the base 211 is opposite to the moving direction of the object 230 in the left-right direction in the figure.

[0047] In this relative movement, the moving part 212 collides with the groove portions 214 and 221 of the curved surfaces 213 and 220, and the kinetic energy of the curved surfaces 213 and 220 is dissipated by the collision. Due to the dissipation of this kinetic energy, the vibration of the curved surfaces 213 and 220 and thus the vibration of the object 230 is attenuated.

[0048] Thus, in the dynamic vibration absorber 300 according to this embodiment, the curved surfaces 213 and 220 are arranged on both the upper and lower sides of the moving part 212 in the vertical direction. According to this configuration, a collision occurs between the moving part 212 and the groove parts 214 and 221 provided on the curved surfaces 213 and 220, respectively. As a result, compared with the configuration in which the curved surface is arranged on one side in the vertical direction with respect to the moving part 212, the kinetic energy dissipated for the same vibration becomes larger, so that the vibration of the object 230 can be efficiently attenuated.

[0049] FIG. 8 is a diagram schematically showing the configuration of a dynamic vibration absorber 400 according to another example. The dynamic vibration absorber 400 shown in FIG. 8 includes a mass body 310 and curved surfaces 313 and 320. The mass body 310 has a base part 311 and a moving part 312 (312A, 312B). Similar to the dynamic vibration absorber 300 shown in FIG. 6, the dynamic vibration absorber 400 shown in FIG. 8 is provided with curved surfaces 313 (313A, 313B) and 320 (320A, 320B) on both the upper and lower sides of the moving part 312 in the vertical direction. On the other hand, the dynamic vibration absorber 400 is different from the above-described dynamic vibration absorber 300 in that the lower curved surface 320 (on the object 330 side) is not provided with a groove part, and the upper curved surface 313 (on the base part 311 side) is provided with a groove part 314.

[0050] Thus, for the curved surfaces 313 and 320 provided on the upper and lower sides, by not arranging the groove part on the lower curved surface 320, the amount of dissipation of the kinetic energy when the moving part 312 collides with the groove part 314 can be reduced compared with the case where the groove parts are arranged on both the upper and lower curved surfaces 313 and 320. In the configuration shown in FIG. 8, it is also possible to adopt a configuration in which the groove part is not arranged on the upper curved surface 313 and the groove part is arranged on the lower curved surface 320.

[0051] FIG. 9 is a diagram schematically showing the configuration of a curved surface according to another example. As in the example shown in FIG. 9, the curved surface 20A may have a configuration in which the grooves 21A are not provided at equal pitches in the bending direction D. In the example shown in FIG. 9, the curved surface 20A has a configuration in which no groove 21A is provided at the central portion in the bending direction D, and grooves 21A are provided on both sides of the central portion in the bending direction D. Thus, by adjusting the arrangement of the grooves 21A, the amount of dissipated kinetic energy when the moving part 12 collides with the grooves 21A can be adjusted. Note that the arrangement of the grooves 21A is not limited to the example shown in FIG. 9. For example, in the curved surface 20A, a groove 21A may be provided at the central portion in the bending direction D, and no grooves 21A may be provided on both sides of the central portion in the bending direction D, or the grooves 21A may be arranged at arbitrary positions regardless of the position in the bending direction D.

[0052] FIG. 10 is a diagram schematically showing the configuration of a curved surface according to another example. As in the example shown in FIG. 10, the curved surface 20B has a configuration in which the grooves 21B are not provided at equal pitches in the bending direction D, and further, the dimensions of the grooves 21B in the bending direction D (hereinafter referred to as the "width" of the grooves 21B) are not the same. Specifically, the curved surface 20B has a configuration in which no groove 21B is provided at the central portion in the bending direction D, and grooves 21B are provided on both sides of the central portion in the bending direction D. Also, the width of the groove 21B becomes smaller as it moves away from the central portion to both sides in the bending direction D. Thus, by adjusting the arrangement and dimensions of the grooves 21B, the amount of dissipated kinetic energy when the moving part 12 collides with the grooves 21B can be adjusted. Note that the dimensions in the width direction of the grooves 21B are not limited to the example shown in FIG. 10. For example, the width of the groove 21B may become larger as it moves away from the central portion to both sides in the bending direction D, or the width of the groove 21B may be arbitrarily set regardless of the position in the bending direction D.

[0053] The technical scope of the present invention is not limited to the above-described embodiments, and appropriate modifications can be made without departing from the spirit of the present invention. For example, in the above-described embodiments, the case where the curved states of the curved surfaces 20, 20A, 20B, 120, 120A, 120B, 213, 213A, 213B, 220, 220A, 220B, 313, 320 are cylindrical has been described as an example, but it is not limited to this configuration, and a curved surface different from a cylindrical shape may be used.

[0054] Further, in the above-described embodiments, the configuration in which the moving parts (12, 112, 112A, 112B, 212, 212A, 212B, 312, 313) rotate and roll around the axis of the rotation axis AX has been described as an example, but it is not limited to this configuration. A configuration in which the moving part does not rotate, that is, a configuration in which the moving part slides on the curved surface may be used. In this case, the portion of the moving part in contact with the curved surface can have a curved shape such as an arc shape.

Explanation of Reference Numerals

[0055] 10, 110, 210, 310... Mass body 11, 111, 211, 311... Base 11a... Lower surface 12, 112, 112A, 112B, 212, 212A, 212B, 312, 312A, 312B... Moving part 20, 20A, 20B, 120, 120A, 120B, 213, 213A, 213B, 220, 220A, 220B, 313, 313A, 313B, 320, 320A, 320B... Curved surface 21, 21A, 21B, 121, 214, 221, 314... Groove part 21w... Wall part 30, 130, 230, 330... Object 100, 200, 300, 400... Dynamic vibration absorber

Claims

1. A curved surface that is concave and has at least one groove formed in the bending direction, and moves in response to the vibration of the object, A moving part that rolls or slides on the curved surface, and a mass body that moves in the bending direction by the rolling or sliding of the moving part Comprising, When the moving part rolls on the curved surface, the surface that rolls on the curved surface is a cylindrical surface, and when the moving part slides on the curved surface, the surface that slides on the curved surface is a curved surface Vibration absorber.

2. The curved surface is provided on the object so as to vibrate integrally with the object The vibration absorber according to claim 1.

3. The curved surface is formed in a cylindrical shape The vibration absorber according to claim 1.

4. A plurality of the moving parts are provided, One curved surface is provided for the plurality of the moving parts The vibration absorber according to claim 1.

5. A plurality of the moving parts are provided, One or more curved surfaces are provided for each of the moving parts The vibration absorber according to claim 1.

6. A plurality of the groove parts are provided, The plurality of groove parts are arranged at equal pitches in the bending direction The vibration absorber according to claim 1.

7. The curved surface is arranged on at least one of the upper side and the lower side with respect to the moving part The vibration absorber according to claim 1.

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