JP4434846B2 - Leaf spring type dynamic vibration absorber - Google Patents

Description

  The present invention relates to a leaf spring type dynamic vibration absorber that absorbs and suppresses vibration of a structure having a relatively low frequency such as a bridge, a house, and a bridge accessory by a small and simple mechanism.

  As a type of dynamic vibration absorber that absorbs vibration of a vibrating structure, a plate spring type dynamic vibration absorber of a cantilever type in which a weight is attached to the tip of a leaf spring and mainly absorbs vibration in the vertical or horizontal direction is known. Yes. As an example, a “leaf spring type dynamic vibration absorber using a viscoelastic body or a viscous body as an attenuator” according to Patent Document 1 is known. In this leaf spring type dynamic vibration absorber, one end of two or more parallel leaf springs with a predetermined interval on a surface perpendicular to the vibration damping direction is fixed with a spring fixing bracket, and the other end of the leaf spring or the vicinity thereof is fixed. A weight is fixed so that the position can be adjusted, and one or more viscoelastic bodies or viscous dampers are connected between two adjacent leaf springs, and the spring fixing bracket is fixed to the structure to be damped. It is what you did.

  Examples of similar cantilever type dynamic vibration absorbers are disclosed in Patent Documents 2 and 3. In the dynamic vibration absorber of Patent Document 2, an elastic body interposed between a supporting column and a horizontal arm having a weight at the tip is provided, and a viscoelastic body is interposed between the arm and a portion that moves relative to the arm. It is configured. Further, the dynamic vibration absorber of Patent Document 3 is configured by attaching an elastic body to a base portion and attaching a weight at a predetermined position of a stay extended from the elastic body apart from the elastic body.

  In the configuration of the dynamic vibration absorber of Patent Document 3 described above, the stay uses a steel plate that does not bend even when vibration is transmitted from the vibration suppression target to the weight provided at the tip thereof. Alternatively, a thin elastic body is placed between the weight and the object to be damped, and the vibration is absorbed through this elastic body. Cannot be controlled. When trying to reduce the overall size, including the arm made of steel plate to which the heavy weight is attached, which can control long-period vibrations, the structure is complicated and many parts are required like the dynamic vibration absorber of Patent Document 2. It will be costly.

  On the other hand, it is described that the dynamic vibration absorber of Patent Document 1 can suppress vibrations with a long period and a small amplitude, and the apparatus is simple and downsized, and can reduce maintenance. However, this dynamic vibration absorber is actually confirmed at the level of an experimental device for a bridge model, and is not practical. In the embodiment, the leaf spring is as thin as 1.5 mm, the weight is as light as 0.4 kg × 2, and the viscoelastic damper is a small block of 10 × 10 × 5 mm. Moreover, although it is described that the long-period minute amplitude is controlled, the actual frequency of the object to be controlled is 4 to 5 Hz, and is suitable for vibration control of bridges and houses generally set to about 1.5 to 3 Hz. Absent.

  To make the dynamic vibration absorber of Patent Document 1 the basic structure and form as it is, and to realize a size and weight that are adapted to the size of bridges and houses, the leaf spring thickness is 6 mm, the weight mass Even if 15 kg × 2 is used, the value of the damping constant is extremely small, and the performance as a dynamic vibration absorber is insufficient. This is because in this dynamic vibration absorber, two or more leaf springs are fixed with bolts and nuts at the other end near the weight with the viscoelastic damper sandwiched between them. This is because it is necessary to connect the leaf springs to each other in order to prevent the weights from vibrating separately.

If the leaf springs are fixed with bolts and nuts via viscoelastic dampers, the movement of the weights vibrate in the same phase, but the upper leaf springs are displaced relative to the lower leaf springs, making it difficult to displace. Even if shear deformation occurs in the viscoelastic damper due to the deviation, the damping effect is not expected. In addition, when the weight is repeatedly displaced, the bolts and nuts are gradually slackened each time, the mutual connection state is changed, the damping effect is further reduced, and the frequency band of the damped vibration is changed. Become. The above inconvenience becomes more remarkable when the two weights at the tip of the leaf spring are connected to one.
JP 59-110938 A JP-A-63-53330 JP-A-61-70242

  In consideration of the above problems, the present invention has a simple structure, is reduced in size and weight as a whole, can be easily attached to a vibration suppression object, and the damping effect varies depending on the fixed state of the attachment portion. However, it is an object of the present invention to provide a leaf spring type dynamic vibration absorber that effectively acts on minute vibrations in a lower frequency range than conventional ones.

  As a means for solving the above problems, the present invention provides a weight at one end of a support arm having a leaf spring of a predetermined length, and a restraint plate with a high damping rubber material sandwiched between the leaf spring of the support arm, The high-attenuation rubber material and the restraint plate are discontinuous by a predetermined length between the end near the one end and the weight, and the high-attenuation rubber material is vulcanized and bonded to the leaf spring and the restraint plate with an adhesive. The other end of the leaf spring is a leaf spring type dynamic vibration absorber configured so as to be cantilevered with a restraining plate by a fixing means together with the restraining plate.

  The leaf spring type dynamic vibration absorber of the present invention configured as described above is composed of extremely simple and simple components, and effectively attenuates long-period micro vibrations of about 1.5 to 3 Hz with high damping performance. be able to. This dynamic vibration absorber supports a weight at the tip of a cantilevered support arm, and a leaf spring and a restraint plate are fixed to the base end of the support arm, and the change in the fixed state by the fixing means is attenuated by a high damping rubber material. In order not to affect the performance, the high-damping rubber material is set to a length that extends only before the fixed position, and the restraint plate and the leaf spring act independently as a damper between the restraint plate and the leaf spring. It is joined only to the leaf spring.

  Since the base ends of the restraint plate and the leaf spring are fixed to the fixed position by the fixing means, if the vibration of the object to be controlled is transmitted to the weight via the support arm, the weight will vibrate from the object to be controlled. And the phase is shifted so as to cancel the vibration of the object to be controlled. For this reason, in the support arm, the leaf spring is displaced according to the displacement of the weight, but the restraint plate is fixed to the fixed portion and is not connected to the weight, so that it is disengaged from the leaf spring and displaced. This displacement deviation is greatly damped by the damper with the high-damping rubber material acting independently, so that the damping effect is extremely large, and the vibration of the object to be damped can be effectively reduced.

  The leaf spring type dynamic vibration absorber of the present invention includes a support arm whose base end is fixed to the object to be controlled by a fixing means, and a weight provided at the tip thereof, and the support arm is provided between the leaf spring and the restraining plate. High damping rubber material is vulcanized and bonded as a damper, and the weight, restraint plate, and high damping rubber material are discontinuous, so the configuration is simple and simple, and about 1.5 to 3 Hz It has the effect of effectively attenuating with a high damping capacity for long period micro vibrations.

  Embodiments of the present invention will be described below with reference to the drawings. 1A is an external perspective view of a leaf spring type dynamic vibration absorber of the embodiment, and FIG. 1B is an exploded perspective view thereof. This leaf spring type dynamic vibration absorber comprises a cantilevered support arm 1 made of a leaf spring of a predetermined length, a weight 2 provided at the tip thereof, and a fixing means 3 for fixing the base end of the support arm 1. . The support arm 1 is provided with a constraining plate 1c overlapped with a leaf spring 1a with a high damping rubber material 1b interposed therebetween. The leaf spring 1a is provided as an elastic member for constituting a dynamic vibration absorber, transmits vibrations from the vibration damping object to the weight 2, and has a relatively large deflection and a high repeated bending strength, such as SUP9. Spring material is used.

  The highly damped rubber material 1b is made of highly damped natural rubber, and is sandwiched between the constraining plate 1c and the leaf spring 1a and strongly bonded by vulcanizing and bonding both surfaces with an adhesive. It is provided as a sex damper. The restraint plate 1c is a thin steel plate (stainless steel plate in the example shown, thickness 1.5 mm), and is attenuated by shear deformation of the high damping rubber material 1b provided between the restraint plate 1c and the leaf spring 1a. The mechanism is configured. The shear deformation is a deformation that occurs with respect to vibration in a direction orthogonal to the extending direction of the support arm 1 in which the weight 2 includes the leaf spring 1a.

FIG. 3 shows an enlarged cross-sectional view of the main part of the support arm. As described above, the support arm 1 is formed by laminating the leaf spring 1c, the adhesive layer 1bx, the high damping rubber material 1b, the adhesive layer 1bx, and the restraining plate 1c. The support arm 1 having such a cross-sectional structure is composed of two layers of adhesives, each of which is an undercoat as the adhesive layers 1bx and 1bx, and the adhesive is applied to the leaf spring 1a and the restraint plate 1c. Stacked with the material 1b in between, put them in a mold, take time with pressure and heat (about 150 ° C.), vulcanize and bond, and the adhesive is a strong adhesive with an adhesive strength of 50 kg / cm ² or more A synthetic resin-based vulcanized adhesive having adhesive strength is used.

  In the illustrated example, the weight 2 connected to the tip of the leaf spring 1a is formed by integrally connecting weight plates 2a and 2b divided into two parts at the top and bottom with bolts and nuts, and the leaf spring 1a. Is fixed by sandwiching the end portion near the tip of the two between the two weight plates 2a, 2b. However, the fixing method may be that the leaf spring 1a is fixed to the weight 2 and may be fixed by any other fixing means such as welding or a flange. Further, the weight 2, the high damping rubber material 1 b, and the restraining plate 1 c are formed only by the leaf spring 1 a at a predetermined length portion Lo (see FIG. 2) near the tip of the leaf spring 1 a so that the weight 2, the high damping rubber material 1 b and the restraining plate 1 c are discontinuous. Yes.

  The base end portion of the support arm 1 is fixed by a fixing means 3 in the illustrated example. The fixing means 3 includes a fixing plate 3a and a mounting base 3b. The fixing plate 3a sandwiches a plate spring 1a, a restraint plate 1c and a spacer 3s between two fixing plates, and fastens the two fixing plates with bolts and nuts. The support arm 1 is formed by fixing the lower fixing plate integrally with the mounting base 3b in advance. The high-damping rubber material 1b is set to a length that does not overlap the fixing plate 3a so as not to be fixed by the fixing means 3.

  Accordingly, the spacer 3s has the same thickness as the high-damping rubber material 1b and has the same length as the width of the fixing plate 3a, and is bonded to the high-damping rubber material 1b with an adhesive during high temperature molding. The mounting base 3b is provided with a flange at the lower end of the vertical web material so that it can be attached to the object to be controlled by bolts and nuts. However, the fixing means 3 including the mounting base 3b has the shape of the support arm 1 as shown in FIG. Any other type can be used as long as the base end of the can be fixed. However, the end of the high damping rubber material 1b is formed so as not to be fixed.

The high-damping rubber material 1b is a natural rubber having the following composition and loss factor (tan δ).
(1) Composition content Composition ratio
Natural rubber 100
Process oil 30
Carbon black 80
Zinc flower 10
Stearic acid 1.5
Anti-aging agent 6
Processing aid 2
Vulcanizing agent, vulcanization accelerator 4
(2) Loss coefficient (tan δ)
Tan δ ≈ 0.25 to 0.3 at a frequency of 5 to 50 Hz (measurement amplitude 0.5 mm)
(3) Temperature dependence (measurement frequency 10 Hz)
0 ° to 80 ° C. Loss coefficient tan δ 0.25 to 0.3
0 ° to −50 ° C. Loss coefficient tan δ Max 0.7 to Min 0.1
Outside of extremely cold regions, the effect of temperature is small on the attenuation effect.

  The leaf spring type dynamic vibration absorber having the above-described configuration is highly effective and effective for vibration of the object to be controlled by setting the size and the weight of the weight corresponding to the object to be controlled. It acts as a viable dynamic absorber that can be reliably damped. When vibration is transmitted from the vibration control object, the displacement due to the vibration of the vibration control object causes a shift between the displacement due to the movement of the weight and the displacement direction due to the gravity of the weight, so that the leaf spring 1a (base layer) is deformed. However, the restraint plate 1c is also deformed along with the deformation. At this time, since the base ends of the leaf spring 1a and the restraining plate 1c are fixed by the fixing means 3, a deviation occurs between the bending displacement of the leaf spring 1a and the bending displacement of the restraining plate 1c.

  When deviation occurs in such bending displacement, displacement due to deviation also occurs in the member axial direction, and this deviation displacement is transmitted to the high damping rubber member 1b installed between the leaf spring 1a and the restraint plate 1c, The displacement displacement is absorbed by shear deformation, that is, functions as a damper and a large damping force can be obtained. In this case, the leaf spring 1a as an elastic spring, the high damping rubber material 1b as a damper, and the restraining plate 1c are vulcanized and bonded to both surfaces of the high damping rubber material 1b via the adhesive layer 1bx. It is formed as a support arm 1 in which a spring and a damper are integrally formed as a whole.

  Further, the end surface near the weight 2 of the high damping rubber material 1b is not in contact with the weight 2 and is discontinuous, and the end surface near the fixing means 3 is provided only until just before the fixing means 3. Therefore, the high damping rubber material 1b is connected only to the upper and lower plate materials between the leaf spring 1a and the restraining plate 1c, and is completely separated from other members and provided independently. For this reason, the highly damped rubber material 1b is provided as a highly damped damper that independently absorbs only the difference between the bending deformation of the leaf spring 1a and the bending deformation of the restraining plate 1c.

  For this reason, the structure is extremely simple and the thickness is minimal, and it is much smaller than a typical dynamic vibration absorber that uses an oil damper for the damper. Thus, no looseness occurs, and the fixed state of the base due to aging of the highly-damped rubber does not change, and maintenance can be completely free.

FIG. 4 shows a simplified diagram modeling the dynamic vibration absorber of the above embodiment and each member size symbol.
L _G ; leaf spring length to weight center L _bc ; restraint plate length Lo; discontinuous portion d; rubber thickness

And the vibration suppression object which installs the dynamic vibration absorber of this embodiment shall vibrate as low as about 1.5-3 Hz of main body vibrations, such as a bridge and a house, and the dynamic vibration absorber of illustration is a basic model which fits these The basic specifications are set to the following predetermined values, and the length of the support arm 1, which is a dimension variable member, the length of the restraining plate 1c, the high damping rubber material 1b, and the high damping rubber material 1b When the thickness or the like is changed variously, it is possible to obtain a change in the frequency characteristics (natural frequency) and damping characteristics shown in FIG. In addition, the specifications other than the variable dimensions of the member that is a variable member in the illustrated example are as follows.
Weight 2; 30kgf
Leaf spring 1a: width 50 mm x thickness 6 mm, material SUP9
Restraint plate 1c; width 50 mm × thickness 1.5 mm, material SUS304

FIG. 5 is a graph showing the relationship between the change in the length of the support arm 1 to the center of the weight and its natural frequency, and FIG. 6 is a graph showing the relationship between the change in the length of the restraint plate and the natural frequency. . In Figure 5, the discontinuity Lo = 50 mm constant 4, high damping accordingly when the leaf spring (base layer) the length L _G is varied as shown in the horizontal axis, and the leaf spring length L _G is changed When the rubber material (damping layer) 1b and the restraining plate 1c are also changed, the leaf spring 1a (solid line), the leaf spring 1a + the restraining plate (constraining layer) 1c (dotted line), the leaf spring 1a + the high damping rubber material 1b (damping) The change of the natural frequency (about 2-3 Hz) corresponding to each length change of layer thickness 4, 8, and 12 mm is shown by (circle), (triangle | delta), and ● mark.

In FIG. 6, the leaf spring length L _G = 590 mm in FIG. 4 is constant, the thickness of the high damping rubber material 1b is 12 mm, and the lengths of the restraining plate 1c and the high damping rubber material are changed as shown on the horizontal axis. The change (about 1.5-2Hz) of the natural frequency of the support arm 1 in the case is shown. The solid and dotted lines in FIG. 5 are calculated values, and the circles in FIG. 5 are the actual measurement values.

The value of the damping characteristic (C / Cc) of the dynamic vibration absorber when the thickness of the high damping rubber material (damping layer) 1b and the length of the restraining plate 1c (constraining layer) were changed only for each member was measured. The graphs are shown in FIGS. In FIG. 7, the length of the high-damping rubber material (damping layer) 1b is Lo = 50 mm, and the change in the thickness of the high-damping rubber material 1b when the length of the leaf spring 1a is a variable parameter is the damping characteristic ( FIG. 8 shows the influence on C / Cc). In FIG. 8, the length L _{G of the} leaf spring 1a is constant at 590 mm, the thickness of the high damping rubber material 1b is constant at 12 mm, and the length of the high damping rubber material (damping layer) is changed. Shows the influence of the above on the attenuation characteristic (C / Cc).

  As can be understood from the change in the characteristic of the damping constant in FIGS. 7 and 8, the illustrated dynamic vibration absorber has an extremely large attenuation characteristic and acts as a stable dynamic vibration absorber that is effective and practically usable. If the lengths of the leaf spring 1a, the high damping rubber material 1b, and the restraint plate 1c are variously set, a dynamic vibration absorber having an optimum size and size is set according to the type and size of the object to be damped. And can be provided. However, in the actual design, when the size and dimensions are changed depending on the object to be controlled, the weight of the weight 2, the width and thickness of the leaf spring 1a, the material, the restraining plate 1c The width, thickness, material, etc. are set to the optimum values and materials according to each object.

  As the vibration suppression object, for example, in the example shown in the figure, a main object having a main body frequency of about 1.5 to 3 Hz such as a bridge such as a pedestrian bridge or a house is mainly targeted. Also, because it is a cantilever type, the mass limit is considered to be about 30 kg as the limit of the mechanism. Therefore, when installing on a large scale bridge, etc., multiple dynamic vibration absorption depending on the size of the scale Install the vessel.

  FIG. 9 shows an example in which the dynamic vibration absorber of the embodiment is applied in another different state. This figure is an application example of damping the vibration in the horizontal direction of the object to be damped. (A) Figure is a horizontal mounting example, (b) Figure is a suspended mounting example (pendulum type), and (c) Figure is upright. Examples of installation (inverted pendulum type) are shown. In any case, the support arm 1 is installed so that the overall rigidity can support the weight, and the displacement due to vibration in each direction is displaced in a direction orthogonal to the leaf spring 1a of the support arm 1. The damping action and effect are exactly the same as those in the above-described embodiment, and a description thereof is omitted.

  The leaf spring type dynamic vibration absorber of the present invention optimizes the length of the support arm and the weight of the weight according to the scale and size of various vibration control objects such as bridges, houses, road lighting poles, and signposts. By setting, it can be widely used for various structures.

(A) perspective view of leaf spring type dynamic vibration absorber of the embodiment, (b) exploded perspective view Cross-sectional view of the above Partial enlarged sectional view of the support arm Schematic diagram of leaf spring type dynamic vibration absorber A graph showing the relationship between the change in leaf spring length of the support arm and the natural frequency Graph showing the relationship between the change in the length of the restraint plate of the support arm and the natural frequency A graph showing the relationship between the change in the thickness of the highly damped rubber of the dynamic vibration absorber and the damping constant A graph showing the relationship between the change in the length of the constraining plate of the dynamic vibration absorber and the damping constant Explanatory drawing showing another usage state of leaf spring type dynamic vibration absorber

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Support arm 1a Leaf spring 1b High damping rubber material 1bx Adhesive layer 1c Restraint plate 2 Weight 3 Fixing means 3a Fixing plate 3b Mounting base

Claims (3)

  A weight is provided at one end of a support arm having a leaf spring of a predetermined length, and a restraint plate is provided with a high damping rubber material sandwiched between the leaf springs of the support arm. The high-damping rubber material is vulcanized and bonded to the leaf spring and the restraint plate with an adhesive, and the other end of the leaf spring together with the restraint plate is the object to be damped. A leaf spring type dynamic vibration absorber configured to be fixed in a cantilever manner by a fixing means. The leaf spring type dynamic vibration absorber according to claim 1, wherein the constraining plate is a steel plate thinner than a leaf spring. The leaf spring type dynamic vibration absorber according to claim 1 or 2, wherein the high damping rubber material is provided between one end of the restraint plate and a position before the restraint plate and the leaf spring are fixed by the fixing means.

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