Vibration damping device

Abstract

To provide a vibration damping device that allows for fine adjustment of the fixing position of the leaf spring. [Solution] A vibration damping device for damping vertical vibrations of a building floor, comprising: a base plate; a weight member provided on the base plate so as to be displaceable in the vertical direction; a damping element that provides a damping force to the vertical vibration of the weight member; a leaf spring disposed in the gap between the base plate and the weight member and biasing the weight member upward; a fixing means for fixing the leaf spring to the base plate; and a positioning means for positioning the leaf spring relative to the base plate, wherein the fixing means can adjust the fixing position of the leaf spring steplessly within a predetermined adjustment range, and the positioning means can position the position of the leaf spring relative to the base plate in steps within the predetermined adjustment range.

Description

Technical Field

[0001] The present invention relates to a vibration damping device.

Background Art

[0002] Techniques for damping vibrations of structures using vibration damping devices are known. In buildings, vertical vibrations of the floor due to factors such as people walking inside or vehicles driving outside can sometimes pose problems. Patent Documents 1 and 2 disclose a tuned mass damper (TMD) suitable for damping such vertical vibrations. The vibration damping device represented by TMD is composed of a weight, a spring element, and a damping element. When suppressing the vertical vibration of the floor, its natural frequency is adjusted to be close to the natural frequency of the structural frame of the floor.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] The TMDs of Patent Documents 1 and 2 adjust their spring constants according to the fixed positions of the leaf springs constituting the spring element. In the case of this method, there is room for improvement in applications where fine adjustment of the spring constant is required.

[0005] An object of the present invention is to provide a vibration damping device capable of finely adjusting the fixed position of a leaf spring.

Means for Solving the Problems

[0006] According to the present invention, a vibration damping device for damping vertical vibrations of a building floor, base plate and A weight member is provided on the base plate so as to be displaceable in the vertical direction, A damping element that provides a damping force against the vertical vibration of the weight member, A leaf spring is positioned in the gap between the base plate and the weight member, and biases the weight member upward. Fixing means for fixing the leaf spring to the base plate, The system includes positioning means for positioning the leaf spring relative to the base plate, The fixing means allows the fixing position of the leaf spring to be adjusted steplessly within a predetermined adjustment range. The positioning means is capable of stepwise positioning the position of the leaf spring relative to the base plate within the predetermined adjustment range. A vibration damping device characterized by the above is provided. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a vibration damping device that allows for fine adjustment of the fixed position of the leaf spring. [Brief explanation of the drawing]

[0008] [Figure 1] (A) and (B) are a plan view and a front view of a vibration damping device according to one embodiment of the present invention. [Figure 2] (A) is a cross-sectional view along line AA in Figure 1(B), and (B) is a plan view of the vibration damping device 1 with one of the weight members and leaf springs removed. [Figure 3] (A) is a plan view of the leaf spring, and (B) is a cross-sectional view of line BB in Figure 3(A). [Figure 4] A close-up view of the area around the end of a leaf spring. [Figure 5] A diagram showing another example of an opening. [Figure 6] A diagram showing another example of a positioning structure. [Figure 7] An explanatory diagram of a vibration damping device according to another embodiment. [Figure 8] (A) and (B) are a plan view and a front view of a vibration damping device according to another embodiment. [Figure 9] (A) is a plan view of the leaf spring, and (B) is a cross-sectional view of the CC line in Figure 9(A). [Modes for carrying out the invention]

[0009] The embodiments will be described in detail below with reference to the attached drawings. Note that the following embodiments do not limit the invention as defined in the claims, and not all combinations of features described in the embodiments are essential to the invention. Two or more features from the multiple features described in the embodiments may be combined arbitrarily. Furthermore, identical or similar configurations will be given the same reference numeral, and redundant descriptions will be omitted.

[0010] <First Embodiment> Figures 1(A) and 1(B) are a plan view and a front view of a vibration damping device 1 according to one embodiment of the present invention, Figure 2(A) is a cross-sectional view along line AA in Figure 1(B), and Figure 2(B) is a plan view of the vibration damping device 1 with one of the weight member 3 and leaf spring 5 removed. In each figure, arrows X and Y indicate two mutually orthogonal horizontal directions when the vibration damping device 1 is installed on the floor (e.g., slab) of a building, and arrow Z indicates the vertical direction.

[0011] The vibration damping device 1 is a TMD (Total Mass Dynamic) and comprises a base plate 2, a weight member 3, a damping element 4, and a leaf spring 5 which is a spring element. The vibration damping device 1 has a flattened rectangular parallelepiped shape, particularly a cubic shape, and can be installed in the narrow gap between the floor panel and the slab of a building's floor. By tuning the mass of the weight member 3, the damping specification of the damping element 4, and the spring constant of the leaf spring 5 to correspond to the natural frequency of the floor's structural frame, vertical vibrations of the floor can be dampened.

[0012] The base plate 2 is a rectangular plate-like member and is placed or fixed on the floor of a building. The weight member 3 is a rectangular plate-like member with a greater thickness than the base plate 2. In the case of this embodiment, the base plate 2 and the weight member 3 have the same shape in plan view and are square. When arranging a plurality of vibration damping devices 1 in a matrix, a large number of vibration damping devices 1 can be arranged neatly within a narrower installation area.

[0013] As a guide structure for guiding the displacement of the weight member 3 in the Z direction with respect to the base plate 2, a guide shaft 6 is provided on the base plate 2. Also, this guide serves to prevent the weight member 3 from lateral displacement when a large horizontal force such as an earthquake acts. In the case of this embodiment, a plurality of guide shafts 6 extending in the Z direction are erected at different positions on the base plate 2. A hole 3a into which the guide shaft 6 is inserted is formed in the weight member 3. The relationship between the diameter D1 of the hole 3a and the diameter D2 of the guide shaft 6 is D1 > D2, and the fitting between the guide shaft 6 and the hole 3a is a loose fit. The dimensional relationship between D1 and D2 is, for example, D1 = D2 + 2 mm. Due to the loose fit between the guide shaft 6 and the hole 3a, the weight member 3 can be displaced in the X direction and the Y direction with respect to the base plate 2 within the play range of the guide shaft 6 and the hole 3a.

[0014] The damping element 4 applies a damping force to the vertical vibration of the weight member 3. In the case of this embodiment, the damping element 4 is a block-shaped viscoelastic body, and examples of the viscoelastic body include acrylonitrile-butadiene rubber, butyl rubber, polyurethane, etc. In the case of this embodiment, the damping element 4 is fixed to the base plate 2 and is provided at one position in the central part of the base plate 2. A plurality of damping elements 4 may be provided at different positions on the base plate 2. The damping element 4 is not fixed to the weight member 3 and is in contact with the bottom surface of the weight member 3. However, a configuration in which the damping element 4 is fixed to the weight member 3 and is in contact with the base plate 2 may also be possible. The damping element 4 is arranged in the gap S between the base plate 2 and the weight member 3. Since the damping element 4 is accommodated within the outer shapes of the base plate 2 and the weight member 3, miniaturization of the vibration damping device 1 can be achieved.

[0015] The leaf spring 5 biases the weight member 3 in an upward direction. In this embodiment, there are multiple (four) leaf springs 5, which are positioned at the four corners of the base plate 2 and fixed to the base plate 2. The leaf springs 5 ​​are not fixed to the weight member 3, but are in contact with the bottom surface of the weight member 3. However, the leaf springs 5 ​​may be fixed to the weight member 3 and in contact with the base plate 2.

[0016] The leaf spring 5 is positioned in the gap S between the base plate 2 and the weight member 3. By using the leaf spring 5 as the spring element, for example, fine adjustment of the spring constant is easier compared to a coil spring, and it can be positioned in a narrow gap S. Because the gap S is narrow, if the total height of the vibration damping device 1 is the same, the height of the weight member 3 can be increased, and the mass of the weight member 3 can be increased. In addition, by positioning the leaf spring 5 in the gap S, the leaf spring 5 can be housed within the outer dimensions of the base plate 2 and the weight member 3, thus enabling miniaturization of the vibration damping device 1. Thus, the vibration damping device 1 of this embodiment can be made thinner and cost-effective.

[0017] The leaf spring 5 is fixed to the base plate 2 by a fixing member 7. The fixing member 7 is fixed to a mounting hole 2a formed in the base plate 2. In this embodiment, the fixing member 7 is a bolt, and the mounting hole 2a is a screw hole. The leaf spring 5 is positioned relative to the base plate 2 by a positioning structure 8.

[0018] In addition to Figure 2, the leaf spring 5 and positioning structure 8 will be further explained with reference to Figures 3(A), 3(B), and 4. Figure 3(A) is a plan view of the leaf spring 5, and Figure 3(B) is a cross-sectional view of Figure 3(A) along line BB. Figure 4 is a partially enlarged view of the area around the end of the leaf spring 5.

[0019] The leaf spring 5 in this embodiment is a strip-shaped leaf spring with a rectangular shape in plan view. One end 5a of the leaf spring 5 in the longitudinal direction d1 is a fixed end fixed to the base plate 2, and the other end 5b is a free end that is in contact with the bottom surface of the weight member 3 without being fixed, thus forming a cantilever spring. In the vibration damping device 1 of this embodiment, the weight member 3 is not fixed to the damping element 4 and the leaf spring 5, but is simply placed on them.

[0020] An opening 5c ​​is formed at one end 5a of the leaf spring 5. The screw shaft 7a of the fixing member 7 passes through the opening 5c ​​and is screwed into the mounting hole 2a. The opening 5c ​​is slightly wider than the diameter of the screw shaft 7a and narrower than the head 7b of the fixing member 7. It is a notch extending in the longitudinal direction d1 and has a U-shape that opens to the edge of one end 5a. This notch shape allows for single-stroke machining of the plate material that makes up the leaf spring 5 during processing, reducing the number of processing steps. When the fixing member 7 is fastened to the mounting hole 2a, the leaf spring 5 is sandwiched and fixed between the head 7b and the base plate 2. The fixing position of the leaf spring 5 can be adjusted steplessly within the range of the opening 5c ​​in the d1 direction.

[0021] The leaf spring 5 extends diagonally from one end 5a to the other end 5b in a side view, resisting displacement of the weight member 3 in the direction of approaching the base plate 2. The leaf spring 5 has an S-shape in a side view, with one end 5a bent in a convex arc towards the base plate 2 and the other end 5b bent in a convex arc towards the weight member 3. The radius of curvature of the other end 5b is shorter than the radius of curvature of the one end 5a.

[0022] The other end 5b has an arc-shaped curved surface that abuts against the bottom surface of the weight member 3. When the weight member 3 vibrates up and down, the contact position between the other end 5b and the weight member 3 shifts horizontally (in this embodiment, in the X direction) on the curved surface as the weight member 3 rolls along the curved surface, thereby reducing friction. In addition, in this embodiment, the weight member 3 can be displaced horizontally relative to the base plate 2 within the range of play between the guide shaft 6 and the hole 3a, so friction between the other end 5b and the weight member 3 can be reduced with respect to the vertical vibration of the weight member 3.

[0023] In this embodiment, all four leaf springs 5 ​​have their longitudinal directions aligned in the same direction (X direction). When the weight member 3 vibrates up and down, the contact position between the other end 5b and the weight member 3 shifts in the same direction (X direction) in each leaf spring 5, allowing for smooth movement.

[0024] One end 5a of the leaf spring 5 is also fixed in place with its curved surface in contact with the upper surface of the base plate 2. Depending on the fixing position of the leaf spring 5 relative to the base plate 2, the length L between the fixing position and the contact position with the weight member 3 (effective length of the spring) changes. A shorter length L results in a larger spring constant, while a longer length L results in a significantly smaller spring constant. Furthermore, the inclination θ and height H of the leaf spring 5 relative to the base plate 2 can also be changed depending on the fixing position.

[0025] The positioning structure 8 can position the leaf spring 5 relative to the base plate 2 in steps. By selecting the position of the leaf spring 5 relative to the base plate 2 using the positioning structure 8 and fixing the leaf spring 5 to the base plate 2 with the fixing member 7, the length L changes, and the spring constant of the leaf spring 5 can be finely adjusted. The positioning structure 8 of this embodiment includes a pair of engaging parts 81 provided on the base plate 2 and a plurality of recesses 82 formed in the d1 direction on both sides of one end 5a of the leaf spring 5.

[0026] Each pair of engaging portions 81 is a cylindrical pin member, which is press-fitted into a mounting hole 2b formed in the base plate 2. Each of the multiple recesses 82 has an arc shape that conforms to the outer circumferential surface of the engaging portion 81, and is a wave-shaped cutout continuously formed in the d1 direction on the side of the leaf spring 5. The multiple recesses 82 can be formed, for example, when the leaf spring 5 is shaped by wire cutting, in which case the increase in man-hours and costs due to the formation of the recesses 82 can be avoided.

[0027] The engaging portion 81 engages with one of the multiple recesses 82. By selecting the recess 82 that engages with the engaging portion 81, the position of the leaf spring 5 relative to the base plate 2 can be positioned in stages. To change the recess 82 that engages with the engaging portion 81, the fixing member 7 is loosened to lift the leaf spring 5 away from the base plate 2, the recess 82 is temporarily separated from the engaging portion 81, the leaf spring 5 is slid in the d1 direction, and then lowered onto the base plate 2, thereby easily changing the recess 82 that engages with the engaging portion 81.

[0028] The pair of engaging parts 81 and the fixing member 7 are arranged on line L1. In other words, the centers of the mounting holes 2a and the two mounting holes 2b of the base plate 2 are located on line L1. In this embodiment, line L1 is parallel to the direction d2 which intersects the longitudinal direction d1. The direction d2 is perpendicular to the direction d1. The fixing member 7 and the pair of engaging parts 81 may be positioned offset in the direction d1, but with the configuration of this embodiment, the fixing position of the leaf spring 5 in the direction d1 by the fixing member 7 and the positioning position of the leaf spring 5 in the direction d1 by the pair of engaging parts 81 coincide, making it easy to adjust the spring constant. Also, because the pair of engaging parts 81 are spaced apart in the direction d2, the horizontal rotation of the leaf spring 5 is constrained, and the leaf spring 5 can be securely fixed with a single fixing member 7.

[0029] In this embodiment, by separating the fixing structure and the positioning structure of the leaf spring 5, it is possible to increase the fixing strength while also allowing for fine adjustment of the position (multi-stage adjustment range). That is, the fixing member 7 can be made to a specification specifically for fixing the leaf spring 5, and a relatively large diameter bolt can be used. There are also advantages in terms of assembly man-hours. On the other hand, the positioning structure 8 can be made to a specification specifically for positioning the leaf spring 5, and the engaging portion 81 and recess 82 can be made to relatively small dimensions, and the width of the recess 82 in the d1 direction can be made significantly narrower than the mounting hole 2a. For example, the mounting hole 2a can be a screw hole in the range of M4 to M6, the width of the recess 82 can be in the range of 1 mm to several mm, and the engaging portion 81 can use a knock pin with a diameter in the range of 1 mm to several mm.

[0030] Thus, according to this embodiment, it is possible to finely adjust the fixing position of the leaf spring 5, and moreover, a vibration damping device 1 with high fixing strength of the leaf spring 5 can be obtained.

[0031] The natural frequency of the vibration damping device 1 is determined by the mass of the weight member 3 and the spring constant of the leaf spring 5. When the mass of the weight member 3 is fixed, the leaf spring 5 is tuned. The leaf spring 5 can be roughly tuned by adjusting the plate thickness, overall length, width, and number of plates. Then, fine adjustment is possible by selecting the recess 82 that engages with the engaging part 81. The adjustment range can be increased to several tens of steps by changing the number of recesses 82. The finer the adjustment of the TMD, the better its performance, so having a multi-step adjustment range is a great advantage.

[0032] <Second Embodiment> In the first embodiment, the opening 5c ​​is a U-shaped notch, but it may be a closed hole. Figure 5 shows an example. The leaf spring 5 in Figure 5 has an opening 5c' instead of the opening 5c. The opening 5c' is an elongated hole extending in the d1 direction.

[0033] <Third Embodiment> Various structures can be adopted as the positioning structure 8. Figure 6 is a partially enlarged view of the area around the end of the leaf spring 5 in this embodiment, and is an explanatory diagram of a positioning structure 8A that can be used as an alternative to positioning structure 8. Positioning structure 8 comprises a contact portion 83, a plurality of recesses 84, and an engaging portion 85. The contact portion 83 is a cylindrical pin member and is fixed to the base plate 2. The circumferential surface of the contact portion 83 contacts one side of one end 5a of the leaf spring 5.

[0034] The multiple recesses 84 are wavy cuts continuously formed in the d1 direction on the other side of one end 5a of the leaf spring 5. In this embodiment, each recess 84 has a triangular shape. The engaging portion 85 is a plate-shaped elastic member having an arm portion 85a and a fixing portion 85b. The fixing portion 85b is fixed to the base plate 2 by a fixing member 86 such as a bolt. The fixing portion 85b is also positioned by engaging with a knock pin 87 fixed to the base plate 2.

[0035] The arm portion 85a has a C-shape, with one end integrally connected to the fixed portion 85b, and the other end 85c has a triangular shape that engages with the recess 85. The arm portion 85a is rotatable relative to the fixed portion 85b in the direction of arrow d3 by elastic deformation. Due to this elastic deformation, the end 85c is displaceable in approximately the direction of d2.

[0036] The contact portion 83, the end portion 85c of the engaging portion 85, and the fixing member 7 are arranged on line L2. In this embodiment, line L2 is parallel to the d2 direction. The fixing member 7 and the contact portion 83 and the end portion 85c of the engaging portion 85 may be positioned offset in the d1 direction, but with the configuration of this embodiment, the fixing position of the leaf spring 5 in the d1 direction by the fixing member 7 and the positioning position of the leaf spring 5 in the d1 direction coincide, making it easy to adjust the spring constant. In addition, since the end portion 85c of the engaging portion 85 and the contact portion 83 are spaced apart in the d2 direction, the horizontal rotation of the leaf spring 5 is constrained, and the leaf spring 5 can be securely fixed with a single fixing member 7.

[0037] In this embodiment, when the leaf spring 5 is slid in the d1 direction with the fixing member 7 loosened, the combination of engagement between the end 85c of the engaging portion 85 and the multiple recesses 84 changes while making a "clicking" sound, making it easy to fine-tune the fixing position of the leaf spring 5.

[0038] <Fourth Embodiment> In the first embodiment, a guide shaft 6 that loosely fits into a hole 3a in the weight member 3 was exemplified as a guide structure for guiding the displacement of the weight member 3 in the Z direction relative to the base plate 2, but other structures can also be used. Figure 7 shows one example. In the illustrated vibration damping device 1A, the weight member 3 is a box shape that opens downwards, with its peripheral edge 3b protruding downwards. The base plate 2 is also a box shape that opens upwards, with its peripheral edge 2c protruding upwards. The peripheral edge 2c is inserted inside the peripheral edge 3b to guide the displacement of the weight member 3 in the Z direction relative to the base plate 2. The loose fitting of the peripheral edge 2b inside the peripheral edge 3b allows the weight member 3 to be displaced horizontally relative to the base plate 2.

[0039] <Fifth Embodiment> The vibration damping device 1 of the first embodiment has a flattened rectangular parallelepiped shape overall, but it may have other shapes. Figures 8(A) and 8(B) are a plan view and a front view of the vibration damping device 1B according to this embodiment.

[0040] The base plate 2B is a circular disc member in plan view and is placed on or fixed to the floor of a building. The weight member 3B is a circular disc member in plan view and is thicker than the base plate 2B. In this embodiment, the base plate 2B and the weight member 3B are identical in plan view and are circular with the same diameter. By making the base plate 2B and the weight member 3B disc members, they can be manufactured and processed relatively easily, for example, using a lathe, thereby reducing costs.

[0041] The base plate 2B is provided with a guide shaft 6B, which serves as a guide structure to allow the weight member 3B to be freely displaced in the Z direction relative to the base plate 2B. This guide also plays a role in preventing the weight member 3B from shifting laterally when a large horizontal force such as an earthquake acts on it. In this embodiment, one guide shaft 6B extending in the Z direction is erected at the center CT of the circle of the base plate 2. The center CT is also the center of the circle of the weight member 3B. Arrow CD indicates the circumferential direction of the circle centered at the center CT.

[0042] The weight member 3B has a hole 3a' into which the guide shaft 6B is inserted. The hole 3a' is located in the center of the weight member 3B (specifically at the center CT of the circle) and penetrates the weight member 3B. The fit between the guide shaft 6 and the hole 3a is loose. The weight member 3 is rotatable relative to the base plate 2 in the CD direction, with the center CT as the vertical axis of rotation (center of rotation). Only one guide shaft 6B and one hole 3a' at the center CT are needed, which helps to reduce costs.

[0043] The damping element 4B provides a damping force against the vertical vibration of the weight member 3B. In this embodiment, the damping element 4B is a block-shaped viscoelastic body, such as acrylonitrile butadiene rubber, butyl rubber, or polyurethane. In this embodiment, the damping element 4B is fixed to the base plate 2B and is arranged in multiples (three in this embodiment) on a virtual circle 10 concentric with the center CT. The three damping elements 4B are arranged at equal pitches (120-degree pitches) in the circumferential direction (same as the CD direction) of the virtual circle 10. The damping element 4B is not fixed to the weight member 3B but is in contact with the bottom surface of the weight member 3B. However, the damping element 4B may be fixed to the weight member 3B and in contact with the base plate 2B. The damping element 4B is positioned in the gap S between the base plate 2B and the weight member 3B. Since the damping element 4B is housed within the outer shape of the base plate 2B and the weight member 3B, the vibration damping device 1B can be miniaturized.

[0044] The leaf spring 5B biases the weight member 3B upward. In this embodiment, there are multiple (three) leaf springs 5B. The leaf spring 5B is fixed to the base plate 2 and not fixed to the weight member 3B, but is in contact with the bottom surface of the weight member 3B. However, the leaf spring 5B may be fixed to the weight member 3 and in contact with the base plate 2. The leaf spring 5B is positioned in the gap between the base plate 2B and the weight member 3B. The leaf spring 5B is fixed to the base plate 2B by a fixing member 7, as in the first embodiment, and is positioned by the positioning structure 8. The positioning structure 8A of the third embodiment can also be used as the positioning structure.

[0045] Figure 9(A) is a plan view of the leaf spring 5B, and Figure 9(B) is a cross-sectional view of Figure 9(A) along line CC. Compared to the leaf spring 5 of the first embodiment, the shape of the other end 5b of the leaf spring 5B is different, but the other components are the same. The opening 5c ​​may be an elongated hole as in the second embodiment (Figure 5).

[0046] The leaf spring 5B is a strip-shaped leaf spring with a pentagonal shape in plan view. The tip of the other end 5b has a triangular shape, and its vertex abuts against the bottom surface of the weight member 3B. The vertex of the triangle may be a rounded arc shape (R shape). In side view, the leaf spring 5B extends diagonally from one end 5a to the other end 5b, resisting displacement of the weight member 3B in the direction of approaching the base plate 2B. As in the first embodiment, the length L, inclination θ, and height H can be changed by changing the fixing position of the leaf spring 5B relative to the base plate 2B.

[0047] The contact position between the tip of end 5b and the bottom surface of the weight member 3B is the upward biasing position of the leaf spring 5B relative to the weight member 3B. As shown in Figure 8(A), each of the three biasing positions of the leaf spring 5B is located on a virtual circle 11 concentric with the center CT. Each biasing position is arranged at equal pitches (120-degree pitches) in the circumferential direction (same as the CD direction) of the virtual circle 11. The fixing position of the leaf spring 5B by the fixing member 7 is located on the tangent line TL of the virtual circle 11. The weight member 3B is supported at three biasing positions. In this embodiment, by using a disc member for the weight member 3B, the weight member 3B can be supported with a minimum of three leaf springs 5B, thus reducing the number of leaf springs.

[0048] Although embodiments of the invention have been described above, the invention is not limited to the above embodiments, and various modifications and changes are possible within the scope of the gist of the invention. [Explanation of Symbols]

[0049] 1. Vibration damping device, 2. Base plate, 3. Weight member, 4. Damping element, 5. Leaf spring

Claims

1. A vibration damping device that suppresses vertical vibrations of the floor of a building, base plate and A weight member is provided on the base plate so as to be displaceable in the vertical direction, A damping element that provides a damping force against the vertical vibration of the weight member, A leaf spring is positioned in the gap between the base plate and the weight member, and biases the weight member upward. Fixing means for fixing the leaf spring to the base plate, The system includes positioning means for positioning the leaf spring relative to the base plate, The fixing means allows the fixing position of the leaf spring to be adjusted steplessly within a predetermined adjustment range. The positioning means is capable of stepwise positioning the position of the leaf spring relative to the base plate within the predetermined adjustment range. A vibration damping device characterized by the following features.

2. A vibration damping device according to claim 1, The aforementioned leaf spring is a strip-shaped leaf spring, An opening extending in the longitudinal direction of the leaf spring is formed at one end of the leaf spring. The aforementioned fixing means is A bolt inserted through the aforementioned opening, The base plate is provided with a screw hole formed therein for screwing into the bolt, A vibration damping device characterized by the following features.

3. A vibration damping device according to claim 2, The positioning means is The leaf spring has a plurality of recesses formed in the longitudinal direction on the side of one end, The base plate is provided with an engaging portion that engages with the recess, A vibration damping device characterized by the following features.

4. A vibration damping device according to claim 3, The plurality of recesses are formed continuously in the longitudinal direction. A vibration damping device characterized by the following features.

5. A vibration damping device according to claim 3, The width of the recess is narrower than the screw hole. A vibration damping device characterized by the following features.

6. A vibration damping device according to claim 3, The center of the screw hole and the engaging portion are located on a line perpendicular to the longitudinal direction. A vibration damping device characterized by the following features.

7. A vibration damping device according to claim 2, The positioning means is The first side of one end of the leaf spring has a plurality of first recesses formed in the longitudinal direction, The leaf spring has a second side portion of one end, with a plurality of second recesses formed in the longitudinal direction, A first engaging portion is provided on the base plate and engages with the first recess, The base plate is provided with a second engaging portion that engages with the second recess, A vibration damping device characterized by the following features.

8. A vibration damping device according to claim 2, The positioning means is The first side of one end of the leaf spring has a plurality of recesses formed in the longitudinal direction, The base plate is provided with an engaging portion that engages with the recess, The base plate is provided with a contact portion which contacts the second side portion of one end of the leaf spring, A vibration damping device characterized by the following features.

9. A vibration damping device according to claim 2, The opening is a U-shaped notch that is open at the edge of one end of the leaf spring. A vibration damping device characterized by the following features.

10. A vibration damping device according to claim 2, The positioning means is The leaf spring has a plurality of recesses formed in the longitudinal direction on the side of one end, The base plate is provided with an engaging portion that engages with the recess, The engaging portion is elastically deformable in a direction intersecting the longitudinal direction. A vibration damping device characterized by the following features.

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