Vibration damping device

Abstract

To provide a vibration damping device using a magnetic force, which suppresses a limit of a moving amount of a member on which the magnetic force acts.SOLUTION: The vibration damping device includes an inner member and an outer member configured to reciprocate relative to each other along a first direction, the inner member is disposed inside the outer member in a second direction orthogonal to the first direction, the inner member includes an end member disposed to face a magnetic pole of the outer member in the second direction and formed of a magnetic body, the outer member includes a magnetic device configured to attract the end member in an equilibrium state, and the end member and the magnetic device are restricted from moving in the second direction so as not to come into contact with each other.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a vibration damping device that utilizes magnetic force. [Background technology]

[0002] Conventionally, the invention relates to a magneto-resistive device including a base, an upper annular permanent magnet, a lower annular permanent magnet, a connecting rod, and a central permanent magnet, wherein a metal conductor sleeve is connected to the upper surface of the base, the metal conductor sleeve being a hollow metal cylinder, the base sealing the lower end surface of the metal conductor sleeve, the upper annular permanent magnet and the lower annular permanent magnet having the same shape and both being hollow rings, the upper annular permanent magnet and the lower annular permanent magnet being fitted into an upper annular bushing and a lower annular bushing, respectively, the upper annular bushing and the lower annular bushing being connected to the upper end and the lower end of the inner wall of the metal conductor sleeve, the upper annular permanent magnet, the lower annular permanent magnet, and the metal conductor sleeve being concentric in the axial direction, and the upper annular permanent magnet and the lower annular permanent magnet being fitted into an upper annular bushing and a lower annular bushing, respectively ... concentric in the axial direction, A one-degree-of-freedom magnetic vibration isolation device is known, characterized in that the magnetic poles on the opposing surfaces of the annular permanent magnet and the lower annular permanent magnet have opposite polarities, the axis of the connecting rod is coaxial with the central axis of the metal conductor sleeve, the central permanent magnet is a hollow ring that is concentrically fitted over and fixed to the connecting rod, the upper end of the connecting rod passes through the central hole of the upper annular permanent magnet, the central permanent magnet is located between the upper and lower annular permanent magnets and can move axially together with the connecting rod between the upper and lower annular permanent magnets, and the magnetic poles on the opposing surfaces of the central permanent magnet and the upper annular permanent magnet have opposite polarities, and the magnetic poles on the opposing surfaces of the central permanent magnet and the lower annular permanent magnet have opposite polarities (see, for example, Patent Document 1).

[0003] The single-degree-of-freedom magnetic vibration isolation device disclosed in Cited Document 1 "can generate magnetostatic and dynamic forces without requiring an energy supply and with high reliability. The magnetostatic force is realized by the mutual attraction of opposite poles of a permanent magnet, and the dynamic force is realized by eddy current damping generated by the relative motion of a metal conductor sleeve and a permanent magnet. The magnitude of the magnetostatic force is related only to displacement, and the magnetic force exists even when the device of the present invention is stationary, so it can be considered a type of rigid force. The eddy current damping is related only to the relative motion speed, and exists only when motion occurs in the magnetic mechanism, so it can be considered a type of viscous damping force." Furthermore, this single-degree-of-freedom magnetic vibration isolation device "can be used in parallel with passive vibration isolation structures such as rigid coil springs or air springs to reduce the increase in amplitude value at the natural frequency without affecting the high-frequency damping performance of the passive vibration isolation system, thereby effectively improving the passive vibration isolation performance of the original system." [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6317822 Summary of the Invention [Problem to be solved by the invention]

[0005] The one-degree-of-freedom magnetic vibration isolation device disclosed in Patent Document 1 "opposes the polarity of the magnetic poles on the opposing surfaces of the upper and lower annular permanent magnets" and "the central permanent magnet is located between the upper and lower annular permanent magnets and moves axially between the upper and lower annular permanent magnets together with the connecting rod." Therefore, when the central permanent magnet moves in either the up or down direction from the equilibrium state, the upper or lower annular permanent magnet is present on its extension line, which limits the amount of movement of the central permanent magnet.

[0006] The present invention has been made to solve the above-mentioned problems, and aims to provide a vibration damping device that uses magnetic force and minimizes restrictions on the amount of movement of the member that applies the magnetic force. [Means for solving the problem]

[0007] The vibration damping device of the present invention is a vibration damping device comprising an inner member and an outer member configured to be able to move back and forth relative to each other along a first direction, wherein the inner member is arranged inside the outer member in a second direction perpendicular to the first direction, and comprises an end member made of a magnetic material arranged opposite the magnetic pole of the outer member in the second direction, the outer member comprises a magnetic device configured to attract the end member in an equilibrium state, and movement of the end member and the magnetic device in the second direction is restricted so as not to come into contact. [Effects of the Invention]

[0008] According to the above invention, a magnetic force in the direction of attraction is generated between the inner member and the outer member, and since the movement paths of the inner member and the outer member do not intersect, the movement of the inner member and the outer member is not restricted by each other. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic diagram of a main configuration of a vibration damping device 100 according to a first embodiment. [Figure 2] 2 is an enlarged view of the first end 13 and the magnetic pole 21a of the magnetic device 21 of FIG. 1. FIG. [Figure 3] 2 is a schematic diagram showing a state in which the inner member 10 of the vibration damping device 100 shown in FIG. 1 has moved in the z direction. [Figure 4] 4 is a diagram showing the relationship between the moving distance of the inner member 10 of the vibration damping device 100 according to the first embodiment and the generated magnetic force. FIG. [Figure 5] 1 is a schematic diagram of a main configuration of a vibration damping device 100A that is a modified example of the vibration damping device 100 according to the first embodiment. [Figure 6]6 is a diagram showing the relationship between the moving distance of the inner member 10 of the vibration damping device 100A according to the modified example shown in FIG. 5 and the generated magnetic force. FIG. [Figure 7] 1 is an example of a schematic diagram of a vibration damping device 100 and 100A according to the first embodiment when viewed from above (as viewed from the z direction). [Figure 8] 10 is another example of a schematic diagram of the vibration damping devices 100 and 100A according to the first embodiment in plan view (as viewed from the z direction). FIG. [Figure 9] 1 is a schematic diagram of the main configuration of a vibration damping device 100B which is a modified example of the vibration damping device 100 according to the first embodiment. [Figure 10] 1 is a schematic diagram of the main configuration of a vibration damping device 100C which is a modified example of the vibration damping device 100 according to the first embodiment. [Figure 11] 10 is a schematic diagram of a main configuration of a vibration damping device 200 according to a second embodiment. FIG. [Figure 12] 1. FIG. 4 is a diagram showing the relationship between the movement distance of the inner member 10 and the generated load in the vibration damping device 100 shown in FIG. 1, and the relationship between the expansion / contraction amount of the elastic member 30 and the generated load. [Figure 13] 10 is a diagram showing the relationship between the moving distance of the inner member 10 of the vibration damping device 200 according to the second embodiment and the generated magnetic force. FIG. [Figure 14] 12 is a diagram showing the relationship between the moving distance of the inner member 10 and the generated magnetic force when the vibration damping device 100 in the vibration damping device 200 shown in FIG. 11 is replaced with the vibration damping device 100A shown in FIG. [Figure 15] FIG. 10 is a schematic diagram of a main configuration of a vibration damping device 300 according to a third embodiment. [Figure 16] 16 is a schematic diagram of a state in which the inner member 10 has moved in the z2 direction from the vibration damping device 300 in the state shown in FIG. 15. FIG. [Figure 17] 10 is a schematic diagram of the main configuration of a vibration damping device 100D which is a modified example in which the second end portion 12 is removed from the vibration damping device 100 according to the first embodiment. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] The preferred embodiments of the vibration damping device of the present invention will be described in detail below with reference to the drawings. Note that the embodiments described below are preferred specific examples of the present invention, and therefore various technically preferable limitations are applied, but the scope of the present invention is not limited to these embodiments unless otherwise specified in the following description to the effect that the present invention is limited.

[0011] Embodiment 1 <Vibration damping device 100> FIG. 1 is a schematic diagram of the main configuration of a vibration damping device 100 according to a first embodiment. The vibration damping device 100 shown in FIG. 1 includes an inner member 10 that is movable in the z direction and a fixed outer member 20. The vibration damping device 100 is configured such that, for example, the inner member 10 is connected to another structure and acts to suppress displacement of the structure in the z direction by magnetic force. The vibration damping device 100 is used, for example, to damp vibrations in automobile dampers, seismic isolation devices for buildings, or vibration control devices for machines. Although the first embodiment describes an example in which the inner member 10 moves in the z direction, the vibration damping device 100 may have any structure as long as the inner member 10 and the outer member 20 can move relative to each other in the z direction.

[0012] In the vibration damping device 100, for example, an outer member 20 is formed in a cylindrical shape. The outer member 20 surrounds the inner member 10 from a direction perpendicular to the z direction. The outer member 20 includes a magnetic device 21. In the magnetic device 21, a pair of magnetic poles 21a and 21b are arranged along the z direction in a cross section parallel to the z direction. In FIG. 1, the magnetic devices 21A and 21B are arranged so that the south pole is located at the end in the z1 direction and the north pole is located at the end in the z2 direction. The magnetic devices 21A and 21B may be an integrated magnetic device or may be separate magnetic devices. The z direction may be referred to as the first direction, and the direction perpendicular to the z direction may be referred to as the second direction.

[0013] The inner member 10 is disposed inside the outer member 20 in a direction (x-y direction) perpendicular to the z direction. The inner member 10 has a first end 13 and a second end 12 disposed to be separated in the z direction. The first end 13 and the second end 12 are each made of a magnetic material. In FIG. 1, the first end 13 and the second end 12 are each made of a magnet, but they may be made of a soft magnetic material such as iron or nickel. In other words, the first end 13 and the second end 12 may have no or almost no magnetic force themselves but may be attracted to the magnetic device 21.

[0014] The first end 13 and the second end 12 are connected in the z direction by a connecting member 11. The connecting member 11 is a member for maintaining a constant distance between the first end 13 and the second end 12. The connecting member 11 may be made of a non-magnetic material such as a resin material, or a metal containing a magnetic material. The inner member 10 may include structures that support the first end 13 and the second end 12 at their ends in the z direction, and the structures may be connected in the z direction by the connecting member 11. The structures that support the first end 13 and the second end 12 may be members formed integrally with the connecting member 11, or may be separate members connected by means of members such as bolts or welding. The first end 13 and the second end 12 may be collectively referred to as an end member in some cases. In other words, the first end 13 and the second end 12 constitute an end member.

[0015] The first end 13 and the second end 12 are configured to be attracted to the magnetic pole 21a or 21b of the magnetic device 21 in the balanced state shown in Fig. 1. The tip 13a of the first end 13 is configured to be attracted to the magnetic pole 21a of the magnetic device 21, and is the north pole in the example shown in Fig. 1. The tip 12a of the second end 12 is configured to be attracted to the magnetic pole 21b of the magnetic device 21, and is the south pole in the example shown in Fig. 1.

[0016] Although FIG. 1 does not show structures supporting the inner member 10 and the outer member 20, the vibration damping device 100 may include structures supporting the inner member 10 and the outer member 20. Alternatively, since the inner member 10 is configured to be attracted to the outer member 20, a spacer or bearing may be provided to maintain a predetermined distance between the inner member 10 and the outer member 20 so that the tip 13 a of the first end 13 and the tip 12 a of the second end 12 do not come into contact with the magnetic poles 21 a and 21 b. Furthermore, the distance between the inner member 10 and the outer member 20 in a direction perpendicular to the z-direction may be dynamically controlled. The magnetic force of attraction can be controlled by dynamically controlling the distance between the end members (the first end 13 and the second end 12) and the magnetic device 21 in a direction perpendicular to the z-direction. This allows the damping force of the vibration damping device 100 to be controlled.

[0017] Fig. 2 is an enlarged view of the first end 13 and the magnetic pole 21a of the magnetic device 21 in Fig. 1. Fig. 2(a) schematically illustrates the magnetic force generated at the first end 13. Fig. 2(b) schematically illustrates the distribution of magnetic lines of force in the magnetic device 21. The operating principle of the vibration damping device 100 will be explained using Figs. 1 and 2.

[0018] The tip 13a of the first end 13 of the inner member 10 is positioned to face the magnetic pole 21a of the magnetic device 21 in the x direction. The tip 13a of the first end 13 is a north pole and receives a magnetic force in an attractive direction along the magnetic field lines generated by the magnetic pole 21a of the magnetic device 21 shown in FIG. 2(b). Therefore, as shown in FIG. 2(a), a magnetic force fa is generated at the end of the end face of the tip 13a on the z2 side, and a magnetic force fb is generated at the end of the end face of the tip 13a on the z1 side. These magnetic forces fa and fb can be resolved into x-direction component forces xa and xb and z-direction component forces za and zb. FIG. 2(a) shows the equilibrium state (initial position) of the vibration damping device 100, in which the z-direction component forces za and zb are balanced. Furthermore, the x-direction component forces xa and xb balance with the magnetic force generated between the tip 13a of the first end 13 located on the x2 side shown in FIG. 1 and the magnetic pole 21a of the magnetic device 21A.

[0019] The tip 13a of the first end 13 of the inner member 10 and the tip 12a of the second end 12 of the inner member 10 each have component forces as shown in FIG. 2(a), and therefore the magnetic forces are balanced in the z direction and in a direction perpendicular to the z direction (the x direction in FIG. 2), and the device is stationary. This stationary state of the vibration damping device 100 is called an equilibrium state. If the magnetic forces generated between the inner member 10 and the outer member 20 were ideally balanced, the inner member 10 and the outer member 20 could maintain a state of equilibrium without a support structure. However, since the vibration damping device 100 is connected to an external structure and receives external forces, it has a structure that limits movement of at least the inner member 10 and the outer member 20 in a direction perpendicular to the z direction. The inner member 10 and the outer member 20 may be supported by support members such as bearings, limiting movement in a direction perpendicular to the z direction, or one of them may be fixed. In either case, the inner member 10 and the outer member 20 are configured to be able to move relative to each other at least in the z direction.

[0020] 2(a), the center of the z-direction width of the tip 13a of the first end 13 of the inner member 10 and the tip surface of the magnetic device 21B of the outer member 20 are aligned in the z-direction, in a balanced state. However, for example, when the inner member 10 is subjected to an external force such as gravity, the balanced state shifts in the direction of gravity. At this time, the load on the inner member 10 in the direction of gravity and the magnetic forces generated at the first end 13 and the second end 12 are balanced in the z-direction, and this position is the balanced state.

[0021] FIG. 3 is a schematic diagram showing the state in which the inner member 10 of the vibration damping device 100 shown in FIG. 1 has moved in the z direction. FIG. 3(a) shows the state in which the inner member 10 has moved in the z1 direction, and FIG. 3(b) shows the state in which the inner member has moved in the z2 direction. The inner member 10 is configured so that the first end 13 and the second end 12 are attracted to the magnetic poles 21a and 21b of the magnetic device 21. Therefore, whether the inner member 10 moves in the z1 direction or the z2 direction, the inner member 10 receives a magnetic force in the direction opposite to the direction of movement. That is, when the inner member 10 moves from the equilibrium state in the z1 direction, it receives a magnetic force in the z2 direction, and when the inner member 10 moves from the equilibrium state in the z2 direction, it receives a magnetic force in the z1 direction. In this way, in the vibration damping device 100, a magnetic force is generated in the direction opposite to the direction in which the inner member 10 moved. Therefore, for example, if a structure connected to the inner member 10 is displaced, a magnetic force is generated in the direction opposite to the direction of movement, generating a force that attempts to return the inner member 10 to the equilibrium state. Thus, the vibration damping device 100 damps vibrations induced in structures connected to the inner member 10 .

[0022] FIG. 4 shows the relationship between the movement distance of the inner member 10 of the vibration damping device 100 according to the first embodiment and the generated magnetic force. The movement distance indicates the fluctuation in the relative distance between the inner member 10 and the outer member 20 in the z direction. A large movement distance means that the magnetic poles 21a and 21b of the magnetic devices 21A and 21B are spaced apart in the z direction from the tip 13a of the first end 13 and the tip 12a of the second end 12. The equilibrium state of the vibration damping device 100 is shown as a movement distance of 0. The loads in FIG. 4 are absolute values. That is, in FIGS. 1 and 3, when the inner member 10 moves in the z1 direction, the load shown in FIG. 4 acts in the z2 direction according to the movement distance. When the inner member 10 moves in the z2 direction, the load shown in FIG. 4 acts in the z1 direction according to the movement distance.

[0023] Magnetic force is inversely proportional to the square of the distance between the objects it acts on. Therefore, as shown in Figure 4, if the inner member 10 moves in the z direction relative to the outer member 20, the greater the distance it moves, the weaker the force that pulls the inner member 10 back to equilibrium.

[0024] FIG. 5 is a schematic diagram of the main configuration of a vibration damping device 100A, which is a modified example of the vibration damping device 100 according to the first embodiment. As shown in FIG. 5, the tip 13a of the first end 13 and the tip 12a of the second end 12 of the inner member 10 of the vibration damping device 100A are configured so that their widths become narrower toward the outside in a direction perpendicular to the z-direction. As shown in FIG. 5(a), the tip 13a of the first end 13 and the tip 12a of the second end 12 may be formed with pointed edge portions 13c, 12c, or as shown in FIG. 5(b), the edge portions 13c, 12c may have flat surfaces remaining. In other words, the tip 13a of the first end 13 and the tip 12a of the second end 12 of the inner member 10 may have a trapezoidal shape with inclined portions 13d, 12d such that their widths in the z-direction become narrower toward the tip. Furthermore, as shown in FIG. 5(c), the tip 13a and the tip 12a may have a stepped structure. In this case, a plurality of end faces 13e located inside the edge portion 13c may be provided. That is, the tip 13a and the tip 12a may be formed in a stepped shape.

[0025] Fig. 6 is a diagram showing the relationship between the distance traveled by the inner member 10 of the vibration damping device 100A according to the modified example shown in Fig. 5 and the magnetic force generated. In the case of the vibration damping device 100A, the width of the tip 13a of the first end 13 of the inner member 10 is narrow, so the influence of the magnetic force generated by the edge portion 13c of the tip 13a is large, and the influence of the magnetic force generated by the inclined portion 13d is small. Therefore, when the device is moved in the z direction from the equilibrium state shown in Fig. 5, the influence of the magnetic force generated by the edge portion 13c becomes dominant.

[0026] Therefore, for example, if edge portion 13c of tip 13a of first end 13 moves slightly in the z1 direction, a force is generated in edge portion 13c in the z2 direction, pulling it back to a balanced state. In contrast, the influence of the magnetic force generated in inclined portion 13d is smaller than the influence of the magnetic force generated in edge portion 13c, and the magnetic force that cancels out the magnetic force pulling edge portion 13c back in the z2 direction is small. Therefore, the force that pulls tip 13a of first end 13 back to a balanced state is greater than when tip 13a has a flat surface along the z direction as shown in FIG. 2.

[0027] 2, when tip 13a has a plane along the z direction, moving tip 13a in the z1 direction causes magnetic force fa to increase and magnetic force fb to decrease. In this case, the z-direction component of magnetic force fa (i.e., the force facing the z1 direction) is greater than the z-direction component of magnetic force fb (i.e., the force facing the z2 direction), and the force pulling tip 13a back in the z2 direction is reduced because the z-direction component of magnetic force fa and the z-direction component of magnetic force fb cancel each other out.

[0028] Therefore, in the case of the vibration damping device 100A of the modified example shown in FIG. 5, the reduction in load due to movement of the inner member 10 in the z direction becomes gradual, as indicated by the solid line in the graph of FIG.

[0029] Furthermore, when the width of the tip 13a of the first end 13 and the tip 12a of the second end 12 shown in Fig. 5 is configured to be narrow, it is preferable to configure the edge portions 13c and 12c to be located closer to the magnetic pole of the magnetic device 21 than the tips 13a and 12a which are flat as shown in Fig. 1. By configuring in this way, the vibration damping device 100A shown in Fig. 5 suppresses a decrease in the magnetic force acting on the inner member 10 relative to the vibration damping device 100, and also reduces the decrease in load due to movement of the inner member 10 in the z direction as shown in Fig. 6.

[0030] FIG. 7 is an example of a schematic diagram of the vibration damping devices 100 and 100A according to the first embodiment when viewed from above (as viewed from the z direction). FIG. 7(a) is a diagram illustrating a configuration in which the outer member 20 surrounds the inner member 10 from the x direction and the y direction. As shown in FIG. 7(a), the vibration damping devices 100 and 100A may be configured such that the outer member 20 is formed in a rectangular cylindrical shape and the inner member 10 is disposed inside the outer member 20. The structures shown in FIGS. 1 and 5 show the cross-sectional structure of part AA in FIG. 7(a), which is a cross-sectional structure parallel to the z direction and the x direction. Note that in the vibration damping devices 100 and 100A shown in FIG. 7(a), the cross-sectional structure parallel to the z direction and the y direction is also the same as the structure shown in FIGS. 1 and 5.

[0031] 7(b) is a schematic diagram of another example of the vibration damping devices 100 and 100A when viewed from above (as viewed from the z direction). The outer member 20 does not necessarily have to surround the entire periphery of the inner member 10, and may have a structure in which magnetic devices 21 are arranged on both ends in the x direction.

[0032] Furthermore, the outer member 20 may be circular in plan view or may have another shape, as long as the magnetic poles 21a and 21b of the magnetic device 21 are arranged to face the tip 13a and second end 13b of the first end 13 in a direction perpendicular to the z direction.

[0033] 8 is another example of a schematic diagram of the vibration damping devices 100 and 100A according to embodiment 1 when viewed from the z direction. The inner member 10 may include a magnetic body formed in a triangular shape when viewed from the plan view. The magnetic body is not limited to a triangular shape when viewed from the plan view, and may have other shapes such as a rectangular shape.

[0034] 7(a) and 7(b), the magnetic poles 21a of the magnetic devices 21 of the outer member 20 all have the same polarity when viewed in plan, but the orientation of the magnetic devices 21 is not limited to this. As shown in Fig. 8, the four magnetic devices 21 arranged on each of the four sides of the rectangular outer member 20 are arranged so that the north poles are visible on the two opposing left and right sides and the south poles are visible on the two opposing top and bottom sides. The magnetic poles of the magnets of the inner member 10 are arranged to match the magnetic devices 21 of the outer member 20.

[0035] 9 is a schematic diagram of the main configuration of a vibration damping device 100B, which is a modified example of the vibration damping device 100 according to the first embodiment. In the vibration damping device 100B, the tip 13a of the first end 13 and the tip 12a of the second end 12 of the inner member 10 are configured with a pair of magnetic poles. The magnetic device 21 provided in the outer member 20 has its magnetic poles arranged to match the magnetic poles of the tip 13a of the first end 13 and the tip 12a of the second end 12. With this configuration, the widths of the first end 13 and the second end 12 of the inner member 10 in the x direction are reduced, allowing the width of the vibration damping device 100B to be configured compactly.

[0036] FIG. 10 is a schematic diagram of the main configuration of a vibration damping device 100C, which is a modified example of the vibration damping device 100 according to the first embodiment. The vibration damping device 100C does not have the first end 13 and second end 12 located on the x1 side of the inner member 10 shown in FIG. 1. By configuring the inner member 10 to restrict movement in the x direction and guide movement in the z direction, it is possible to eliminate the first end 13 and second end 12, which are located symmetrically in the x direction. Even with this structure, a force acts on the inner member 10 to return it to an equilibrium state when it moves in the z direction, so it functions in the same way as the vibration damping device 100 shown in FIG. 1.

[0037] The vibration damping devices 100, 100A, 100B, and 100C described above can provide a structure that uses the action of magnetic force to return the inner member 10 and the outer member 20 to a state of equilibrium in a structure that includes an inner member 10 and an outer member 20 that are relatively reciprocable in the z direction. In the vibration damping devices 100, 100A, 100B, and 100C, the outer member 20 is disposed in a position that does not interfere with the direction of movement of the inner member 10. Therefore, whether the inner member 10 moves in the z1 direction or the z2 direction relative to the outer member 20, a load that attempts to return the inner member 10 to a state of equilibrium due to the action of magnetic force acts on the inner member 10, making it possible to damp the vibrating displacement.

[0038] Furthermore, the one-degree-of-freedom magnetic vibration damping device disclosed in Patent Document 1 is configured so that the magnetic force becomes stronger as the displacement in either the vertical direction increases. However, this one-degree-of-freedom magnetic vibration damping device "opposes the polarities of the magnetic poles on the opposing surfaces of the upper and lower annular permanent magnets" and "the central permanent magnet is located between the upper and lower annular permanent magnets and moves axially between the upper and lower annular permanent magnets together with the connecting rod." Therefore, when the central permanent magnet moves in either the vertical or horizontal direction from a balanced state, the magnetic force in the direction of movement increases, and an external force greater than the magnetic force is required to return it to a balanced state. Furthermore, the presence of the upper or lower annular permanent magnet on the extension of the path of the central permanent magnet's movement limits its movement. On the other hand, in the vibration damping devices 100, 100A, 100B, and 100C according to the first embodiment, the outer member 20 is not present on the path of movement of the inner member 10, so the inner member 10 and the outer member 20 do not restrict each other's movement.

[0039] Embodiment 2 A vibration damping device 200 according to embodiment 2 will now be described. The vibration damping device 200 according to embodiment 2 is a combination of the vibration damping device 100 according to embodiment 1 and an elastic member 30. Note that components having the same functions and actions as those in embodiment 1 will be given the same reference numerals and their description will be omitted.

[0040] 11 is a schematic diagram of the main configuration of a vibration damping device 200 according to the second embodiment. The vibration damping device 200 is a combination of the vibration damping device 100 and an elastic member 30. The elastic member 30 is formed, for example, by a helical spring, and is connected to the inner member 10 so that, when the inner member 10 moves in the z direction, a load is applied in the direction opposite to the movement direction. The elastic member 30 is also fixed to a support 31, and is configured so that it can expand and contract in accordance with the movement of the inner member 10.

[0041] Figure 12 is a diagram showing the relationship between the movement distance of the inner member 10 and the generated load, and the relationship between the expansion and contraction amount of the elastic member 30 and the generated load in the vibration damping device 100 shown in Figure 1. As shown in Figure 12(a), in the vibration damping device 100 shown in Figure 1, only magnetic force acts on the inner member 10, so as the movement distance increases, the load decreases in inverse proportion to the square of that distance. As shown in Figure 12(b), when the elastic member 30 shown in Figure 11 expands and contracts in the z direction, a load proportional to the expansion and contraction amount is generated in the opposite direction to the expansion and contraction direction.

[0042] Fig. 13 is a diagram showing the relationship between the movement distance of the inner member 10 of the vibration damping device 200 according to the second embodiment and the generated magnetic force. In the vibration damping device 200, the magnetic force and the load due to the expansion and contraction of the elastic member 30 act on the inner member 10 in accordance with the displacement of the inner member 10, and therefore the reduction in the load acting on the inner member 10 is suppressed compared to the action of the magnetic force alone shown in Fig. 12(a). Therefore, when the inner member 10 is displaced in the z direction, the force that returns the inner member 10 to the equilibrium state decreases while the amount of displacement is small, but as the amount of displacement increases, the force that returns the inner member 10 to the equilibrium state increases due to the action of the elastic member 30.

[0043] In other words, the vibration damping device 200 according to the second embodiment has a smaller change in the force that returns the device to the equilibrium state than the vibration damping device 100 according to the first embodiment.

[0044] Fig. 14 is a diagram showing the relationship between the movement distance of the inner member 10 and the generated magnetic force when the vibration damping device 100 in the vibration damping device 200 shown in Fig. 11 is replaced with the vibration damping device 100A shown in Fig. 5. The two-dot chain line in Fig. 14 shows the relationship between the displacement and load of the inner member 10 in the vibration damping device 200 shown in Fig. 11, and the solid line in Fig. 14 shows the relationship between the displacement and load of the inner member 10 when the inner member 10 shown in Fig. 11 is replaced with that of the vibration damping device 100A shown in Fig. 5. In the vibration damping device 100A shown in Fig. 5, the change in load relative to the displacement of the inner member 10 is gradual, as shown in Fig. 6, so when combined with the elastic member 30, the change in the force pulling back to the equilibrium state is smaller and the change in load becomes closer to flat.

[0045] The elastic member 30 is not limited to a helical spring, but may be a leaf spring, rubber, or any other material that generates elastic force when deformed. In the second embodiment, the elastic member 30 is connected below the inner member 10, but the arrangement of the elastic member 30 can be changed as appropriate. For example, the elastic members 30 may be arranged at intervals in the direction of movement of the inner member 10, and a load from the elastic members 30 may act on the inner member 10 when the movement of the inner member 10 exceeds a predetermined amount. In addition, if the outer member 20 of the vibration damping device 200 is configured to move, the load from the elastic member 30 may be applied to the outer member 20.

[0046] 11 may be disposed between the first end 13 and the second end 12 of the inner member 10. For example, the elastic member 30 may be disposed between the first end 13 and the second end 12 of the inner member 10 and fixed to the outer member 20. In this way, when the inner member 10 moves in the z direction relative to the outer member 20, the inner member 10 comes into contact with the elastic member 30, and the elastic member 30 can function in the same manner as the elastic member 30 of the vibration damping device 200 shown in FIG.

[0047] Embodiment 3 A vibration damping device 300 according to embodiment 3 will now be described. The vibration damping device 300 according to embodiment 3 uses electromagnets as the magnetic devices 21A and 21B of the outer member 20 of the vibration damping device 100 according to embodiment 1. Note that components having the same functions and actions as those in embodiments 1 and 2 will be given the same reference numerals and their description will be omitted.

[0048] FIG. 15 is a schematic diagram of the main configuration of a vibration damping device 300 according to a third embodiment. In the vibration damping device 300 according to the third embodiment, the magnetic device 21 provided in the outer member 20 of the vibration damping device 100 according to the first embodiment is replaced with an electromagnet. The magnetic device 321 formed by an electromagnet can change the positions of the magnetic poles 21 a and 21 b by partially passing a current through it. In FIG. 15, the portions of the magnetic device 321 indicated by solid lines are through which current flows, and the portions indicated by dashed lines are through which current does not flow. The magnetic device 321 shown in FIG. 15 is energized so that the magnetic poles are positioned at positions corresponding to the tip 13 a of the first end 13 and the tip 12 a of the second end 12.

[0049] 16 is a schematic diagram of the vibration damping device 300 in the state shown in FIG. 15 after the inner member 10 has moved in the z2 direction. In FIG. 16, the magnetic device 321 provided in the outer member 20 moves its current-carrying range in the z2 direction in accordance with the movement of the inner member 10. In this way, the magnetic poles 21a and 21b of the magnetic device 321 move in accordance with the movement of the inner member 10, so the vibration damping device 300 can be controlled so that the same magnetic force is applied even if the inner member 10 moves. In the vibration damping device 100 according to the first embodiment, as shown in FIG. 4, the magnetic force decreases as the amount of movement increases when the vibration damping device 100 moves in the z direction. However, according to the vibration damping device 300 according to the third embodiment, the magnetic force acting on the inner member 10 can be maintained approximately constant even if the inner member 10 moves in the z direction.

[0050] The magnetic device 321 of the vibration damping device 100 is configured, for example, by connecting a plurality of coils 324 in the z direction, and is configured so that the coils 324 to be energized can be selected in accordance with the movement of the inner member 10. For example, the magnetic device 321 is configured so that the central axes of the windings of the plurality of coils 324 are arranged along the z direction, and is configured so that the current flowing through each of the plurality of coils 324 can be controlled. In other words, the magnetic device 321 is configured so that the magnetic poles can move in the z direction by controlling the current flowing through the plurality of coils 324. Note that the magnetic device 321 is not limited to being configured so that the plurality of coils 324 are continuously arranged along the z direction as shown in FIGS. 15 and 16 , and can be modified as appropriate, for example, by arranging the plurality of coils at intervals.

[0051] 15 and 16, the outer member 20 includes the magnetic devices 321A and 321B, but these may be an integrated magnetic device 321.

[0052] Furthermore, the magnetic devices 321A and 321B may control the magnetic force that attracts the first end 13 and the second end 12 by controlling the current flowing through the coil 324. This allows the damping force of the vibration damping device 300 to be controlled.

[0053] The configurations shown in the above embodiments are merely examples, and it is possible to omit or change part of the configurations without departing from the gist of the invention.

[0054] FIG. 17 is a schematic diagram of the main configuration of a vibration damping device 100D, which is a modified example in which the second end portion 12 is removed from the vibration damping device 100 according to the first embodiment. The vibration damping devices 100, 100A, 100B, 100C, 200, and 300 shown in the first to third embodiments function as vibration damping devices even when either the first end portion 13 or the second end portion 12 constituting the end member is omitted. In the modified example shown in FIG. 17, the first end portion 13 is supported by a structure 14, and the structure 14 is guided by, for example, a ball bearing 15. Even in this case, the force shown in FIG. 2(a) acts on the first end portion 13, and the magnetic force allows the device to function as a vibration damping device. Furthermore, in this case, the pair of magnetic poles of the magnetic device 21 does not need to be arranged along the z direction; at least one magnetic pole needs to be arranged facing the first end portion 13 in a direction perpendicular to the z direction.

[0055] 17 can also be applied to the vibration damping devices 100A, 100B, 100C, 200, and 300. The structures of the structure 14 and the ball bearing 15 can be modified as appropriate, and the ball bearing 15 can be replaced with a sliding bearing or other support structure.

[0056] Furthermore, the present invention described above using the vibration damping devices 100, 100A, 100B, 100C, 100D, 200, and 300 may also include combinations of the features shown in the following Supplementary Notes 1 to 10. Such combinations are described below.

[0057] [Appendix 1] A vibration damping device including an inner member and an outer member configured to be reciprocally movable relative to each other along a first direction, The inner member is the outer member is disposed inside the outer member in a second direction perpendicular to the first direction, an end member made of a magnetic material and arranged to face the magnetic pole of the outer member in the second direction; The outer member is a magnetic device configured to attract the end member in an equilibrium state; The end member and the magnetic device are Movement in the second direction is restricted to prevent contact. Vibration damping device. [Appendix 2] 2. The vibration damping device of claim 1, The inner member is the end member having a first end and a second end spaced apart in a first direction; a connecting member connecting the first end and the second end in a first direction, The magnetic device is A pair of magnetic poles is arranged along a first direction, Each of the pair of magnetic poles is In a balanced state, the first end and the second end are disposed opposite each other in a second direction, The first end and the second end are In an equilibrium state, the magnetic pole is configured to be attracted to a magnetic pole of the magnetic device that faces in a second direction. Vibration damping device. [Appendix 3] 3. A vibration damping device according to claim 1 or 2, The magnetic device is It consists of multiple magnetic devices, the plurality of magnetic devices and at least one pair of magnetic devices arranged at positions facing each other in the second direction with the inner member interposed therebetween. Vibration damping device. [Appendix 4] A vibration damping device according to any one of appendices 1 to 3, The end member is It is made up of permanent magnets, The magnetic poles of the magnetic device are: The polarity is set to be opposite to that of the end member. Vibration damping device. [Appendix 5] A vibration damping device according to any one of appendices 1 to 3, The end member is Made of soft magnetic material, Vibration damping device. [Appendix 6] A vibration damping device according to any one of appendices 1 to 5, The end member is In a cross section including the central axis of the inner member, the tip in the second direction has a structure in which the width in the first direction narrows as it goes outward from the central axis. Vibration damping device. [Appendix 7] A vibration damping device according to any one of appendices 1 to 6, The device further includes an elastic member that applies a load in a direction opposite to the direction of relative movement between the inner member and the outer member in a first direction, Vibration damping device. [Appendix 8] 8. The vibration damping device of claim 7, The elastic member is connected to at least one of the inner member and the outer member; Vibration damping device. [Appendix 9] A vibration damping device according to any one of appendices 1 to 8, The magnetic device is The pair of magnetic poles are electromagnets configured to be movable in a first direction. Vibration damping device. [Appendix 10] 10. The vibration damping device of claim 9, The magnetic device is a plurality of coils arranged such that their central axes are aligned along a first direction; By varying some of the coils to which current is applied among the plurality of coils, the magnetic poles move in a first direction. Vibration damping device. [Explanation of symbols]

[0058] 10: Inner member 11: Connecting member 12:Second end 12a: Tip 12c: Edge 13:First end 13a: Tip 13c: Edge 13d: Inclined part 14 :Structure 15: Ball bearings 20:Outer member 21: Magnetic devices 21A: Magnetic devices 21B: Magnetic devices 21a: Magnetic pole 21b: Magnetic pole 30: Elastic member 31:Support 100: Vibration damping device 100A: Vibration damping device 100B: Vibration damping device 100C: Vibration damping device 200: Vibration damping device 300: Vibration damping device 321: Magnetic Devices 321A: Magnetic Devices 321B: Magnetic devices 324: Coil

Claims

1. A vibration damping device including an inner member and an outer member configured to be reciprocally movable relative to each other along a first direction, The inner member is the outer member is disposed inside the outer member in a second direction perpendicular to the first direction, an end member made of a magnetic material and arranged to face the magnetic pole of the outer member in the second direction; The outer member is a magnetic device configured to attract the end member in an equilibrium state; The end member and the magnetic device are Movement in the second direction is restricted to prevent contact. Vibration damping device.

2. 2. The vibration damping device according to claim 1, The inner member is the end member having a first end and a second end spaced apart in a first direction; a connecting member connecting the first end and the second end in a first direction, The magnetic device is A pair of magnetic poles is arranged along a first direction, Each of the pair of magnetic poles is In a balanced state, the first end and the second end are disposed opposite each other in a second direction, The first end and the second end are In an equilibrium state, the magnetic pole is configured to be attracted to a magnetic pole of the magnetic device that faces in the second direction. Vibration damping device.

3. 3. The vibration damping device according to claim 1 or 2, The magnetic device is It consists of multiple magnetic devices, the plurality of magnetic devices at least one pair of magnetic devices arranged at positions facing each other in the second direction with the inner member interposed therebetween; Vibration damping device.

4. 3. The vibration damping device according to claim 1 or 2, The end member is It is made up of permanent magnets, The magnetic poles of the magnetic device are: The polarity is set to be opposite to that of the end member. Vibration damping device.

5. 3. The vibration damping device according to claim 1 or 2, The end member is Made of soft magnetic material, Vibration damping device.

6. 3. The vibration damping device according to claim 1 or 2, The end member is In a cross section including the central axis of the inner member, the tip in the second direction has a structure in which the width in the first direction narrows as it goes outward from the central axis. Vibration damping device.

7. 3. The vibration damping device according to claim 1 or 2, The device further includes an elastic member that applies a load in a direction opposite to the direction of relative movement between the inner member and the outer member in a first direction, in response to the relative movement between the inner member and the outer member in a first direction. Vibration damping device.

8. 8. The vibration damping device according to claim 7, The elastic member is connected to at least one of the inner member and the outer member; Vibration damping device.

9. 3. The vibration damping device according to claim 1 or 2, The magnetic device is The pair of magnetic poles are electromagnets configured to be movable in a first direction. Vibration damping device.

10. 10. The vibration damping device of claim 9, The magnetic device is a plurality of coils arranged such that their central axes are aligned along a first direction; By varying a part of the coils to which current is applied among the plurality of coils, the magnetic poles are moved in a first direction. Vibration damping device.

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