Rack vibration damping structure

Abstract

In a standalone rack installed in a warehouse or similar facility, the response acceleration and response displacement are appropriately reduced in response to various seismic motions. [Solution] The rack 1, in which multiple shelves 2 are supported on columns 4 erected at the four corners, is equipped with a support end pulley unit 20 installed on the end face in the long direction of the rack 1 and fixedly supported on the end face of the rack 1, with multiple coaxial fixed pulleys 21 forming a pair substantially horizontally; a movable end pulley unit 30 fixedly supported on the end face of the rack 1 above the support end pulley unit 20 so that multiple coaxial movable pulleys 31 are positioned vertically opposite to the multiple coaxial fixed pulleys 21, with multiple coaxial movable pulleys 31 forming a pair substantially horizontally; a braking damper 40 fixedly supported on the end face of the rack 1 so as to be located between the pair of coaxial movable pulleys 31; and a wire W whose both ends are fixed to a fixed part and is stretched between the support end pulley unit 20, the movable end pulley unit 30, and the braking damper 40.

Description

Technical Field

[0001] The present invention relates to a rack vibration damping structure, and more particularly to a rack vibration damping structure for reducing the shaking of goods and materials stored in a rack installed in an automated warehouse or a warehouse along the loading and unloading direction during an earthquake.

Background Art

[0002] In conventional automated warehouses and warehouses, a plurality of slender and tall racks (shelves) with a relatively large height ratio with respect to the loading and unloading direction (rack short side direction) of goods and materials are installed in parallel in the warehouse. In these warehouses, even when an earthquake occurs that does not cause damage to the building or the racks to collapse, the racks shake violently, and there are frequent damages such as the goods and materials in the racks jumping out or falling. Therefore, in order to improve the seismic resistance of the racks and ensure the stability of the goods and materials stored on the racks, measures have been taken to connect and reinforce the upper parts of adjacent racks with beams to increase the horizontal rigidity and reduce the response displacement (for example, Patent Document 1), and a rack warehouse has also been proposed in which vibration damping devices are arranged on the upper part of the racks and a seismic isolation structure serving as a seismic isolation layer is arranged at the lower part of the racks (Patent Document 2).

[0003] In the storage shelf disclosed in Patent Document 1, the upper parts of a plurality of adjacent racks arranged in parallel are connected and reinforced with a beam provided with a damper to increase the horizontal rigidity and reduce the response displacement, thereby improving the seismic resistance of the racks. In the rack warehouse disclosed in Patent Document 2, a movable mass and a damping part functioning as a TMD are installed in the vibration damping device at the top of the rack. On the other hand, a sliding mechanism for supporting the entire rack is installed in the seismic isolation layer at the lower part of the rack.

[0004] Furthermore, the applicant (in part) of the present application has proposed a seismic damping structure for racks that is completely different in structure from Patent Documents 1 and 2 (Patent Document 3). In the seismic damping structure for racks disclosed in Patent Document 3, a seismic damping device is incorporated that connects adjacent racks at the top of the racks, and a wire cable is stretched on one side of each rack in a predetermined overhead wire shape (Z-shape) to limit the displacement behavior of the racks during an earthquake. Similarly, a wire cable is stretched in a Z-shape on the other side of each rack, and by overlapping both sides of the racks, a wire overhead wire shape that is X-shaped when viewed from the side is formed. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2004-51271 [Patent Document 2] Japanese Patent Publication No. 2018-131317 [Patent Document 3] Japanese Patent Publication No. 2015-51865 (Patent No. 6031424) [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] The structure disclosed in Patent Document 1, which enhances the seismic resistance of multiple parallel racks, is effective in suppressing the response displacement of the racks during an earthquake, but it is ineffective against higher-order vibrations such as secondary and tertiary modes. Therefore, the risk of cargo materials flying out or falling from the racks due to the response acceleration in higher-order modes cannot be eliminated. In addition, in automated warehouses, the connecting beams at the top of the racks may be an obstacle to the operation of automated lifts.

[0007] In the structure disclosed in Patent Document 2, where a seismic isolation layer is constructed at the bottom of the rack, the height of the rack changes, and there are problems such as the difficulty in securing clearance due to seismic isolation and the high cost of installing the seismic isolation device itself.

[0008] The seismic damping structure disclosed in Patent Document 3, like the invention in Patent Document 1, has a configuration in which a seismic damping device is installed at the top of the rack, connecting adjacent racks, and wires in a predetermined tension line shape are stretched along the sides of each rack. Therefore, it is not intended to improve the seismic damping performance of a single rack.

[0009] Therefore, the objective of the present invention is to resolve the problems of the conventional technology described above and to provide a rack vibration control structure that appropriately reduces response acceleration and response displacement in response to various seismic motions in a single rack by installing an inexpensive vibration control mechanism. [Means for solving the problem]

[0010] The present invention provides a rack vibration damping structure installed on the end face in the long direction of a rack, which is a rack in which multiple shelves are supported by columns erected at the four corners, in order to dampen vibrations occurring in the short direction of the rack, comprising: a support end pulley unit fixedly supported on the end face of the rack and having a pair of multiple coaxial fixed pulleys arranged substantially horizontally; a movable end pulley unit fixedly supported on the end face of the rack above the support end pulley unit such that multiple coaxial movable pulleys are positioned vertically opposite to the multiple coaxial fixed pulleys and having a pair of the coaxial movable pulleys arranged substantially horizontally; and between the pair of coaxial movable pulleys The system comprises a braking damper fixedly supported on the end face of the rack so as to be positioned, and a wire whose both ends are fixed to a fixed part and which is stretched between the support end pulley unit, the movable end pulley unit, and the braking damper, wherein the wire is stretched from one of the pair of coaxial fixed pulleys of the support end pulley unit and the pair of coaxial movable pulleys of the movable end pulley unit toward one of the coaxial movable pulleys located diagonally above, passes through the braking damper, and is stretched through the other coaxial movable pulley toward the other coaxial fixed pulley located diagonally below.

[0011] The wire is stretched between the support end pulley unit and the movable end pulley unit such that it forms an X-shaped overhead wire when viewed from the end face.

[0012] The support end pulley unit is fixedly supported at the lower end of the rack, the movable end pulley unit is fixedly supported at the top of the rack, and the wire is stretched between the support end pulley unit and the movable end pulley unit.

[0013] The support end pulley unit is fixedly supported at the lower end of the rack, and the movable end pulley unit is fixedly supported at the intermediate layer and the top of the rack. The wire is stretched between the support end pulley unit and the movable end pulley unit at the top via the movable end pulley unit at the intermediate layer, forming an X-shaped wire overhead configuration when viewed from the end face, connected in the vertical direction.

[0014] When the rack is displaced relative to the fixed part, the wire undergoes a predetermined displacement between the support end pulley unit and the movable end pulley unit, and the amount of the wire's displacement passes through the braking damper, thereby attenuating the energy that displaces the rack.

[0015] The amount of displacement of the wire is amplified in proportion to the number of coaxial pulleys relative to the amount of relative displacement that occurs in the rack at the position where the movable end pulley unit is installed.

[0016] The aforementioned braking damper consists of a rotary damper, and the wire wound around the spool of the rotary damper passes through while experiencing rotational resistance.

[0017] The wire is set to be stretched from one of the coaxial fixed pulleys to one of the coaxial movable pulleys located diagonally above, following the direction of the assumed relative displacement of the assumed higher-order vibration mode relative to the fixed part of the rack. [Effects of the Invention]

[0018] According to the present invention, by externally installing a vibration damping mechanism on a newly installed or existing rack, it is possible to appropriately reduce the response acceleration and response displacement of an individual rack during an earthquake. [Brief explanation of the drawing]

[0019] [Figure 1] Overall perspective view showing a rack in which an embodiment of the rack vibration damping structure of the present invention is installed. [Figure 2] Partial perspective view showing an enlarged view of the rack vibration damping structure shown in FIG. 1. [Figure 3] Front view and side view showing an enlarged view of the configuration of the pulley unit used in the rack vibration damping structure and the state of wire laying. [Figure 4] Perspective view showing an enlarged view of the configuration and operating state of the rotary damper incorporated in the rack vibration damping structure. [Figure 5] Schematic model diagram showing various arrangement examples of the pulley unit in the rack vibration damping structure and the wire laying shape. [Figure 6] Schematic model diagram showing another installation example of the rotary damper in the rack vibration damping structure and the wire laying shape thereof. [Figure 7] Schematic model diagram showing an arrangement example of a plurality of pulley units and rotary dampers in the rack vibration damping structure and the wire laying shape thereof. [Figure 8] Schematic model diagram showing an arrangement example of the pulley unit provided in a part of the rack and the wire laying shape of the rack vibration damping structure. [Figure 9] Schematic model diagram showing an arrangement example of the pulley unit corresponding to the case where the rack vibrates in a high-order mode and the wire laying shape. [Figure 10] End view schematically showing the entire rack in which an embodiment of the rack vibration damping structure is installed on both end faces of the rack. [Figure 11] Side view schematically showing the entire rack in which a plurality of embodiments of the rack vibration damping structure are installed overlappingly on both end faces of the rack. [Figure 12] Test body model diagram used in the vibration damping effect confirmation test in the rack vibration damping structure. [Figure 13] Test body model diagram in each case of the vibration damping effect confirmation test. [Figure 14] Graph showing the maximum response acceleration in each layer in each case shown in FIG. 13. [Figure 15] Figure 13 shows a graph illustrating the maximum response displacement in each layer for each case. [Modes for carrying out the invention]

[0020] Hereinafter, embodiments of the rack vibration damping structure of the present invention will be described with reference to the attached drawings.

[0021] The present invention provides a rack vibration damping structure in which multiple pulley units are installed on the end faces of the rack, and wires are stretched between each pulley unit to form a predetermined overhead wire shape. The inter-story displacement that occurs in the rack during an earthquake is converted into the displacement of the wire using the principle of pulleys, amplified, and then passed through a damping damper installed at the top of the rack, thereby further enhancing the vibration damping effect. As a result, the damper effect can be exerted from small to large earthquakes, reducing the response acceleration and response displacement of the rack.

[0022] Figure 1 shows an entire rack on which one embodiment of the rack vibration damping structure 10 is installed. As shown in the figure, the rack 1 on which the rack vibration damping structure 10 is installed has sufficient length in the direction of the long side of the rack, and each shelf 2 has a planar shape with a narrow width in the direction of loading and unloading of cargo materials (short side of the rack), which is not shown. For example, it consists of a configuration in which five shelves 2 and a top plate 3 are supported by columns 4 erected at the four corners. The rack vibration damping structure 10 of the present invention is installed at both end faces in the direction of the long side of the rack 1 in order to suppress the horizontal acceleration and horizontal displacement in the direction of the short side of the rack during an earthquake in various racks of a similar shape to this rack 1. Note that, in this specification, for the sake of simplicity in the figures, reinforcing members such as braces that stiffen the structure of the entire rack 1 and each part are not shown. Also, in this specification, the faces in the direction of the short side of the rack 1 are referred to as end faces, but they may be read as side faces.

[0023] Figure 2 shows an enlarged view of one of the vibration damping structures of the rack vibration damping structure 10 installed on both ends of the rack in Figure 1. As shown in the figure, the rack vibration damping structure 10 comprises a support end pulley unit 20 consisting of two fixed pulleys 21 fixedly supported near the lower end of the column 4 of the rack 1 and arranged approximately horizontally apart to form a pair; a movable end pulley unit 30 consisting of two movable pulleys 31 fixedly supported near the upper end of the column 4 of the rack 1 and arranged approximately horizontally apart to form a pair; and a damping damper 40 located between the pair of movable end pulley units 30, stretched between each pulley unit, and controlling the amount of displacement (movement) of the wire W passing between the movable end pulley units 30 at the top of the rack 1a to reduce its energy.

[0024] In this embodiment, the movable pulley 31 and fixed pulley 21 of the movable end pulley unit 30 and the support end pulley unit 20, which are arranged in an upper and lower position, are of the same shape and, as an example, consist of three (n=3) coaxial pulleys (a group of multiple pulleys supported in parallel on a single rotating shaft and capable of rotating independently) (Figures 3(a), (b)). Both the coaxial fixed pulley 21 and the coaxial fixed pulley 31 are pivotally supported by bearing brackets (not shown), and the bearing brackets are fixedly supported on a shelf 2 or a part of a column 4 of the rack 1 (Figure 2). Hereinafter, unless the position and function of the support end pulley unit 20 and the movable end pulley unit 30 are specified, they will simply be referred to as pulley units 20, 30, coaxial pulleys 21, 31, etc.

[0025] Here, the configuration of each component of the support end pulley unit 20, the movable end pulley unit 30, and the braking damper 40 shown in Figure 2 will be explained with reference to Figures 3 and 4. Figure 3(a) shows the movable pulley 31 and the wire W wound around it of one of the movable end pulley units 30 shown in Figure 2, and Figure 3(b) shows the coaxial fixed pulley 21 and the wire W wound around it of the support end pulley unit 20 located diagonally below the coaxial movable pulley 31 of the movable end pulley unit 30 in Figure 3(a), and the fixed part F1 to which one end of the wire W is anchored.

[0026] As shown in Figures 2, 3(a), and 3(b), one end of the wire W is fixed to a fixed part F1 (floor surface or base near rack 1, etc.) near one coaxial fixed pulley 21 of the support end pulley unit 20, and is stretched so as to make two turns between one coaxial fixed pulley 21 and one coaxial movable pulley 31 of the movable end pulley unit 30 located diagonally above it. Furthermore, the wire W, whose direction is changed by one coaxial movable pulley 31 at the top of the rack 1a, extends to the braking damper 40 (Figure 4), passes through the braking damper 40 and extends to the other coaxial movable pulley 31 and the coaxial fixed pulley 21 at the lower end of rack 1 located diagonally below it, and is stretched so as to make two turns between the coaxial movable pulley 31 and the coaxial fixed pulley 21, with the other end fixed to a fixed part F2.

[0027] As described above, a single wire W is stretched between the movable end pulley unit 30 and the support end pulley unit 20, which form a pair at the upper and lower positions, so that when the entire rack 1 is viewed from the end face, the overhead wire shape is X-shaped (Figure 2). The number of coaxial pulleys 21 and 31 incorporated into the pulley units 20 and 30, respectively, is related to the amplification factor of the response displacement of the rack 1 during an earthquake, as will be described later. Therefore, the number of pulleys is determined from the relationship between the amount of movement of the wire W and the amount of movement that the damping damper 40 can control.

[0028] Figure 4 shows a partially disassembled view of the configuration and operating state of the braking damper 40 of this embodiment. In this embodiment, a rotary damper (hereinafter denoted by reference numeral 40) is used as the braking damper 40. As shown in Figure 4, the spool 41 of this rotary damper 40 has its rotation axis (axis X) supported by a bracket 43 so that it can rotate due to the movement of the wound wire W. A rotor 42 is built into the shaft portion of the spool 41, which acts with a predetermined viscous resistance in the direction of rotation. Therefore, when the wire W is wound around the spool 41 several times and the wire W moves (winds and unwinds) and the spool 41 rotates, the spool 41 receives rotational resistance from the internal rotor 42, limiting its rotational speed and amount of rotation. This rotary damper 40 provides an energy damping effect when the wire is displaced (moves).

[0029] The braking damper 40 can be a rotary-type damper, a direct-acting oil damper, a steel-based hysteresis damper, or the like. In the case of a direct-acting oil damper, the amount of wire displacement (movement) is controlled by the extension and contraction resistance of a cylinder rod having a predetermined stroke. The type and mechanism of the braking damper 40 are not limited, but the damping mechanism of the damper should be able to operate in a manner that sufficiently follows the expected amount of wire displacement (movement) W.

[0030] [Relationship between the installation position of the pulley unit and the amplification factor] In the rack 1 vibration damping structure 10 of the present invention, as described above, a wire W is stretched between coaxial pulleys 21 and 31 of a pair of pulley units 20 and 30 installed at predetermined positions on the rack end face 1b. The inter-story displacement d that occurs in the rack 1 during an earthquake is converted into movement (displacement) D of the wire W via the pulley units 20 and 30 and amplified. At this time, the displacement amplification factor of the amount of movement D of the wire W with respect to the inter-story displacement d caused by the horizontal displacement during an earthquake can be adjusted according to the number of pulleys (n) around which the wire W is circulated. Furthermore, if the angle (inclination angle) between the wire W stretched between the pulley units 20 and 30 and the floor surface (horizontal support surface) is θ, then n·cosθ can be obtained as the displacement amplification factor. Therefore, as shown in Figure 2, arranging multiple sets of pulley units 20 and 30 in the intermediate layer 5 of rack 1 reduces the inclination angle θ of the stretched wire W and increases the displacement amplification factor, compared to installing pulley units 20 and 30 at the lower end and top 1a of rack 1 so that the wire cable shape is a long, narrow, large X shape across the entire rack end face 1b.

[0031] Each figure in Figure 5 is a model diagram of a modified rack vibration damping structure 10, in which the installation positions of the pulley units 20 and 30 are changed based on the relationship described above, and wires W are sequentially stretched between the pulley units 20 and 30 installed in the intermediate layer 5 of the rack 1, so that the X-shaped wire overhead configuration between the pulley units 20 and 30 is continuous in the vertical direction. In each model diagram referenced in this specification, for explanatory purposes, the coaxial pulleys 21 and 31 of the pulley units 20 and 30 and the wire overhead configuration are shown enlarged relative to the rack shape shown in the diagram. As shown in Figure 5(a), when a horizontal load acts in the direction of the arrow and horizontal displacement occurs in the rack 1, the displacement of the pulley position of the movable end pulley unit 30 causes tension to be generated in one wire W that appears to be on the tension side of the X-shaped wires W stretched between the pulley units 20 and 30, which restricts elongation, and an equivalent tension is generated in the other wire W that appears to be on the compression side to compensate for the elongation. To represent this state, in each model diagram, when rack 1 is horizontally displaced, the wire W acting as the tensioning wire W is shown as a solid line, and the wire W acting as the compressioning wire W is shown as a dashed line.

[0032] Figure 5(a) is a schematic model diagram showing the wire cable configuration shown in Figures 1 and 2. In this model diagram, the coaxial fixed pulley 21 of the support end pulley unit 20 is attached to a fixed part near the lower end of the column 4 of the rack 1, and the coaxial movable pulley 31 of the movable end pulley unit 30 is attached near the upper end of the column 4 of the rack 1, and the inclination angle of the wire W, which is stretched in an X shape as a whole, is θ A In contrast, in the model diagram shown in Figure 5(b), in addition to the movable end pulley unit 30 installed on the top 1a of the rack, two sets of movable end pulley units 30 are arranged on the intermediate layer 5, and in the model diagram shown in Figure 5(c), in addition to the movable end pulley unit 30 installed on the top 1a of the rack, five sets of movable end pulley units 30 are arranged on the intermediate layer 5, and the wire W is stretched sequentially from the support end pulley unit 20, through the movable end pulley units 30 installed on each intermediate layer 5, to the movable end pulley unit 30 on the top 1a of the rack. The inclination angle of the wire W stretched so that these multiple X shapes are arranged vertically is θ B , θC Therefore, in each model diagram, the displacement amplification factor described above is as follows: Figure 5(a) < Figure 5(b) < Figure 5(c) (θ A >θ B >θ C ) However, as shown in Figure 5(c), when multiple movable end pulley units 30 are arranged on the intermediate layer 5 of the rack 1, the wire length becomes very long, which increases the amount of elastic deformation of the wire W, and may impair smooth wire movement. To prevent this, it is preferable to divide the wire W.

[0033] [Variations of rack vibration damping structure] The following describes modified versions of the rack vibration damping structure 10 shown in Figure 5(a) as the basic structure, with improvements made to its structure, shape, and function, referring to Figures 6 to 8. Figure 6 shows a modified version of the rack vibration damping structure 10 shown in Figure 5(a) in which a damping damper 40 is installed on the lower end of the rack 1. For example, when the damping damper 40 is placed at the lower end of the rack 1, the added mass on the top of the rack 1a can be reduced, and maintenance of the damping damper 40 can be made easier.

[0034] Figure 7(a) shows a modified example in which two sets of pulley units 20 and 30 are arranged vertically within the rack 1, and braking dampers 40 are installed on the intermediate layer 5 through which the wires W of each set pass, and on the top of the rack 1a. Similarly, Figure 7(b) shows a modified example in which three sets of pulley units 20 and 30 are arranged within the rack 1, and two braking dampers 40 are installed on the intermediate layer 5 and one on the top. When braking dampers 40 are installed on the intermediate layer 5, the wires W are divided and stretched over each pulley unit 20 and 30. Furthermore, when multiple sets of pulley units 20 and 30 are installed, the mechanism can be made more compact by having each coaxial pulley 21 and 31 share a rotation axis with other coaxial pulleys 21 and 31, as shown in Figure 3(c). In the modified example shown in Figure 7(b), the number of damping dampers 40 increases compared to the modified example in Figure 7(a), and the inclination angle θ of the wire W becomes smaller, thus further improving the vibration damping performance of the rack 1.

[0035] Figure 8(a) shows a modified example in which the rack vibration damping structure 10 of the present invention is installed only on the lower half of rack 1, in a rack 1 on which relatively lightweight cargo materials are placed and stored. In such a rack 1, if vibration damping performance can be achieved in the range from the fixed end (floor) up to a certain height, sufficient stability can be expected in the upper part. When considering equipment costs, this type of vibration damping structure can be adopted. Furthermore, as shown in Figure 8(b), in the case of a rack 1 with a structure that provides sufficient rigidity to the columns 4 in the lower half of rack 1, it is also possible to install the rack vibration damping structure 10 of the present invention only on the upper half of rack 1.

[0036] [Vibration damping structure that takes higher-order vibration modes into consideration] The rack 1 into which the rack vibration damping structure 10 of the present invention is incorporated has sufficient height relative to its width in the short-side direction. Therefore, in addition to the primary mode, it is necessary to consider vibrations in higher-order modes as well as the primary mode during an earthquake. When the above-described X-shaped wire cable configuration is applied to the displacement of the rack 1 in higher-order modes, compression displacement may occur in the wire W between the pulleys at certain displacement points, reducing the displacement of the wire W and potentially resulting in areas where the damping effect of the damping damper cannot be exerted. As a countermeasure, by arranging the wire W in a cable configuration that follows the displacement direction of the rack 1, sufficient tensile force can be applied to the wire W against vibrations in higher-order modes, thereby providing tensile resistance and suppressing the response acceleration and response displacement in higher-order modes.

[0037] A vibration damping structure that takes higher-order modes into consideration will be explained with reference to the figures in Figure 9. Figure 9(a) is a model diagram of a rack vibration damping structure 10 that is designed to exhibit vibration damping performance in the first mode as a reference example. As shown in the figure, in the first mode, the rack 1 is displaced relative to the fixed part only in the X direction. Therefore, among the three X-shaped wires W that are continuously stretched in the vertical direction of the rack 1, a sufficient tensile force (indicated by the symbol T) acts on each wire W that is stretched in the direction of the displacement, the X direction, and a sufficient vibration damping effect is exerted on the rack 1 that is displaced in the first mode.

[0038] Figure 9(b) is a model diagram of a rack vibration damping structure designed to exhibit vibration damping performance in the secondary mode. As shown in the figure, in the secondary mode, the shape of the rack 1 after relative displacement with respect to the fixed part is such that the middle part of the rack 1 is bent, and the whole structure becomes roughly V-shaped. Therefore, by setting the arrangement of the movable end pulley unit 30 to follow this displacement direction and changing the direction of the wire W through each pulley, sufficient tensile force can be applied to the corresponding range (indicated by the symbol T) of the stretched wire W, thereby exhibiting vibration damping performance for the rack 1 displaced in the secondary mode.

[0039] Figure 9(c) is a model diagram of a rack vibration damping structure designed to exhibit vibration damping performance in the third mode. As shown in the figure, in the third mode, the displaced rack 1 takes on a shape similar to an S (a shape in which two opposite inverted V-shapes are connected vertically), as shown in the figure. Therefore, as in the case of the second mode, the arrangement of the movable end pulley units 30 is set to follow this direction of displacement, and the wire W is changed direction and stretched through each pulley, so that sufficient tensile force is applied to the corresponding range (indicated by the symbol T) of the stretched wire W, thereby exhibiting vibration damping performance for the rack 1 displaced in the third mode.

[0040] [Examples of superimposed application of vibration damping structures] An example of the superposition of the rack vibration damping structure 10 described above will be explained with reference to Figures 10 and 11. Figure 10 schematically shows the entire front surface of rack 1 on which the rack vibration damping structure 10 shown in Figure 1 is installed. In the rack vibration damping structure 10 shown in this figure, vibration damping structures of the same shape are installed on both end faces 1b, 1b in the direction of the long side of the rack, preventing twisting of rack 1 during an earthquake. In contrast, if the dimensional difference between the long side and the short side of rack 1 is not large, it is thought that vibration damping performance for the entire rack 1 can be obtained by installing a vibration damping structure on only one end face 1b. Furthermore, by installing vibration damping structures 10 consisting of different wire traction shapes on one end face 1b and the other end face 1b of rack 1, or by applying vibration damping structures 10 consisting of different wire traction shapes in a superposition manner on one end face 1b of rack 1, as shown in Figure 11, it is possible to achieve more effective vibration damping performance against complex input earthquake motions. In this case, it is preferable that the coaxial pulleys 21 and 31 of each pulley unit 20 and 30 share a rotation axis with other coaxial pulleys 21 and 31, as shown in Figure 3(c). Furthermore, the rack vibration damping structure 10 described above can be installed not only simultaneously on the rack end face 1b when a new rack 1 is constructed, but also added to an existing rack 1 through post-construction, or superimposed on an existing vibration damping structure to add further functionality.

[0041] [Experiment to verify the vibration damping effect of rack vibration damping structure] The vibration damping effect (response displacement, response acceleration) of the rack vibration damping structure of the present invention was confirmed by comparing it with that of a rack without a vibration damping structure through model experiments. Figure 12 schematically shows the structure, appearance, and excitation direction of the test model (6-layer shear test specimen model). Figure 13 shows the test model diagram of the wire frame shape for each case. (Test specimen model) Vibration experiments were conducted using the following four test specimen models, representing racks equipped with the rack vibration damping structure of the present invention and racks without the vibration damping structure. In the test specimen models, laminated rubber was interposed between each layer to adjust the rigidity of each layer. Linear sliders were also installed to suppress bending deformation during vibration and to allow horizontal displacement to prevail. Case 0: Rack body only (no vibration damping structure) Case 1: Wire cable configuration (X-shape, two levels, upper and lower), 1 seismic damper. Case 2: Wire cable configuration (<,> shape, 1 tier), 1 seismic damper Case 3: Wire cable configuration (X-shape, 3 levels vertically), 1 seismic damper (Excitation (vibration) conditions) • Test equipment: A test specimen model, representing a rack body without the vibration damping structure shown in Figure 12, was placed on a three-dimensional vibration table. Wires were then stretched across the front and back surfaces of this test specimen model to match the wire arrangement for each case. • Input wave: Notification wave • Vibration method: The vibration table is vibrated with a specified wave (10% to 120%) with an adjusted vibration magnification. (Vibration test results) Figures 14 and 15 show the layer-by-layer response displacement and layer-by-layer response acceleration for each test specimen model (each case) under the above-described test conditions (40% of the specified wave). As can be seen from the graph in Figure 15, simply installing a vibration damping structure capable of handling primary mode input waves in a rack that does not have a vibration damping structure can sufficiently reduce the displacement at each layer of the rack. Regarding the response acceleration shown in the graph in Figure 14, the results were obtained that were lower than the input acceleration at layers 4 to 6 of the test specimen model. In addition, primary mode deformation was dominant in all test specimen models of this shape.

[0042] It should be noted that the present invention is not limited to the embodiments described above, and various modifications are possible within the scope of each claim. In other words, embodiments obtained by combining technical means that have been appropriately modified within the scope of the claims are also included in the technical scope of the present invention. [Explanation of Symbols]

[0043] 1 rack 4 pillars 10. Rack vibration damping structure 20 Support end pulley unit 21 Coaxial fixed pulley 30 Mobile End Pulley Unit 31 Coaxial pulley 40. Brake damper (rotary damper) 42 rotors W Wire

Claims

1. A rack vibration damping structure installed on the end face in the long direction of a rack, in order to dampen vibrations occurring in the short direction of a rack, in which a multi-tiered shelf board is supported by columns erected at the four corners, A support end pulley unit is fixedly supported on the end face of the rack, and consists of multiple coaxial fixed pulleys arranged in pairs in a substantially horizontal manner. A movable end pulley unit is fixedly supported on the end face of the rack above the support end pulley unit, such that multiple coaxial movable pulleys are positioned opposite each other in the vertical direction to the multiple coaxial fixed pulleys, and the coaxial movable pulleys form a pair substantially horizontally. A braking damper fixedly supported on the end face of the rack so as to be located between the pair of coaxial pulleys, A wire is stretched between the support end pulley unit, the movable end pulley unit, and the braking damper, with both ends fixed to a fixed part. Equipped with, The rack vibration damping structure is characterized in that the wire is stretched from one of the pair of coaxial fixed pulleys of the support end pulley unit and the pair of coaxial movable pulleys of the movable end pulley unit, from one of the coaxial fixed pulleys to one of the coaxial movable pulleys located diagonally above, passes through a damping damper, and is stretched through the other coaxial movable pulley to the other coaxial fixed pulley located diagonally below.

2. The rack vibration damping structure according to claim 1, wherein the wire is stretched between the support end pulley unit and the movable end pulley unit such that it forms an X-shaped overhead wire when viewed from the end face.

3. The rack vibration damping structure according to claim 1 or claim 2, wherein the support end pulley unit is fixedly supported at the lower end of the rack, the movable end pulley unit is fixedly supported at the top of the rack, and the wire is stretched between the support end pulley unit and the movable end pulley unit.

4. The rack vibration damping structure according to claim 1, wherein the support end pulley unit is fixedly supported at the lower end of the rack, the movable end pulley unit is fixedly supported at the intermediate layer and the top of the rack, and the wire is stretched between the support end pulley unit and the movable end pulley unit at the top via the movable end pulley unit at the intermediate layer, and an X-shaped wire overhead line is formed when viewed from the end face in a series in the vertical direction.

5. The rack vibration damping structure according to claim 1, wherein when the rack is displaced relative to the fixed part, the wire undergoes a predetermined displacement between the support end pulley unit and the movable end pulley unit, and the amount of the wire's displacement passes through the damping damper, thereby attenuating the energy that displaces the rack.

6. The rack vibration damping structure according to claim 5, wherein the amount of displacement of the wire is amplified in proportion to the number of coaxial movable pulleys with respect to the relative displacement amount that occurs in the rack at the position where the movable end pulley unit is installed.

7. The rack vibration damping structure according to claim 5, wherein the braking damper consists of a rotary damper, and the wire wound around the spool of the rotary damper passes through while experiencing rotational resistance.

8. The rack vibration damping structure according to claim 1, wherein the wire is set to be stretched from one of the coaxial fixed pulleys to one of the coaxial movable pulleys located diagonally above, in accordance with the direction of the assumed relative displacement of the assumed relative displacement of the higher-order vibration mode of the rack with respect to the fixed portion.

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