JP6387241B2 - Vibration control device - Google Patents

Description

  The present invention relates to a vibration damping device.

  A hybrid mass damper (HMD) is known as a device that reduces vibrations of equipment machines such as motors, pumps, and conveying devices and vibrations of buildings caused by earthquakes. As this type of HMD, for example, active vibration dampers disclosed in Patent Documents 1 to 4 are known. In such an active vibration damper, a two-degree-of-freedom vibration system is formed, and the natural frequency is set to two (primary natural frequency, secondary natural frequency). As a result, the frequency region where the damping force is amplified by resonance is widened, and the frequency region where the damping object can be damped is widened.

  Here, the dominant frequency of the generated vibration may differ from the previous vibration investigation and analysis results depending on the type and operation of the heavy machine that is the source of generation or the characteristics of the ground. In such a case, it may be necessary to change the natural frequency of the vibration control device in accordance with the dominant frequency at the site.

  However, in order to adjust the natural frequency of the vibration damping device, it is necessary to lift the heavy movable mass and replace the movable mass and the spring. For this reason, for example, a heavy machine or a crane must be newly arranged. That is, it is not easy to adjust the fixed frequency of the vibration damping device on the site according to the dominant frequency of the generated vibration.

JP 2001-173715 A Japanese Patent Laid-Open No. 2001-200885 JP 2005-337497 A JP-A-3-74648

  An object of the present invention is to provide a vibration damping device capable of easily adjusting the natural frequency in view of the above facts.

The invention according to claim 1 is a plurality of movable masses connected in series with an elastic member, an excitation means for exciting a first movable mass having a smaller mass among the adjacent movable masses, and the first movable mass A mass that can be adjusted to the mass, and an adjustment mass that is smaller in mass than the first movable mass, and the plurality of movable masses are connected in series in the vertical direction and configured to vibrate in the vertical direction The vibration means is a vibration damping device provided on the top of the first movable mass.

  According to the first aspect of the present invention, a plurality of movable masses are connected by an elastic member, so that a multi-degree-of-freedom vibration system is configured and a plurality of natural frequencies are obtained, so that an excitation force is amplified. The frequency range is widened, and the frequency range in which the object to be controlled can be controlled is increased. The natural frequency can be easily adjusted by adjusting the mass of the adjustment mass that is provided on the first movable mass to be moved and has a mass smaller than that of the first movable mass.

According to the second aspect of the present invention, when the mass ratio between the mass of the second movable mass having the larger mass among the adjacent movable masses and the mass of the first movable mass is μ, 0.01 ≦ μ ≦ 0. It is set to be 05 .

According to the invention described in claim 2, by setting 0.01 ≦ μ ≦ 0.05 , the amount of change (adjustment amount) of the natural frequency caused by adjusting the mass of the adjustment mass is large. Become.
According to a third aspect of the present invention, the first movable mass is formed of a rectangular metal plate material in plan view, and the vibration means is provided in a central portion of the upper portion of the first movable mass in plan view. 3. The vibration damping device according to claim 1, wherein the adjustment mass is bolted to an upper corner portion of the first movable mass in a plan view.

  According to the present invention, the natural frequency of the vibration damping device can be easily adjusted.

It is a front view of the vibration damping device of one embodiment of the present invention. The graph which shows the relationship between the natural frequency, the amplification magnification which amplifies and transmits the excitation force of the vibrator to the ground, and the mass ratio μ between the mass M1 of the first movable mass and the mass M2 of the second movable mass. It is. It is a graph which shows the change of the amplification magnification and the natural frequency which amplify and transmit the excitation force of the shaker at the time of adding adjustment mass m3 to Case1 of FIG. It is a graph which shows the change of the amplification magnification and natural frequency which amplify and transmit the excitation force of a vibration exciter to the ground at the time of adding adjustment mass m3 to Case2 of FIG. It is a graph which shows the change of the amplification magnification and natural frequency which amplify and transmit the excitation force of the shaker at the time of adding adjustment mass m3 to Case3 of FIG. It is a graph which shows the change of the amplification magnification and natural frequency which amplify and transmit the excitation force of the vibration exciter to the ground at the time of changing the elasticity modulus of the 1st elastic member of Case1 of FIG. Two damping devices are installed: a damping device in which 48 kg of adjusting mass m3 is added to Case 1 in FIG. 3 and a modified damping device in which the elastic modulus of the first elastic member of Case 1 in FIG. It is a graph which shows the sum total of the amplification magnification and natural frequency which amplify and transmit the excitation force of the vibration exciter to the ground in the case of doing. FIG. 2 is a vibration model diagram of the vibration damping device of FIG. 1. It is a vibration model figure of another damping device.

<Embodiment>
Hereinafter, a vibration damping device according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 shows a front view of a vibration damping device 10 according to an embodiment of the present invention, and FIG. 8 shows a vibration model diagram of the vibration damping device 10.

  The vibration damping device 10 reduces (vibrates) the vibration of the vibrating body based on the same principle as a so-called HMD (hybrid mass damper). In the present embodiment, the vibrating body is the ground G in which vibration is generated during construction work such as new construction work or dismantling work, and the vibration damping device 10 reduces (vibrates) the vibration of the ground G.

  As shown in FIG. 1, the vibration damping device 10 includes a first movable mass 100, a second movable mass 200, a first frame 120, a second frame 220, a first connection part 150, and a second connection part 250. ing.

  The first movable mass 100 is made of a metal plate having a rectangular shape in plan view. In addition, an exciter 400 and a plurality of detachable adjustment masses 300 made of a metal plate material are provided on the upper portion of the first movable mass 100.

  The vibration exciter 400 is provided at the center of the first movable mass 100 in plan view. The adjustment mass 300 is bolted to the four corners (each corner) of the first movable mass 100 in plan view. Therefore, the number of adjustment masses 300 can be easily increased or decreased, that is, the mass can be easily adjusted.

  The second movable mass 200 is composed of a plurality of masses 201, 202, 203, 204, 205, 206, 207, 208, 209, 210, 211, 212, 213 made of a metal block material, The plurality of masses 201 to 213 are integrated by bolt fastening.

  The first pedestal 120 has a structure in which the steel members 122 and 124 are arranged in a rectangular frame shape and joined in a plan view. Similarly, the second frame 220 has a structure in which the steel members 222 and 224 are arranged in a rectangular frame shape and joined in a plan view.

  The first connecting part 150 includes a first elastic member 152 and a first telescopic shaft 154. Similarly, the second connecting part 250 includes a second elastic member 252 and a second telescopic shaft 254.

  The 1st elastic member 152 and the 2nd elastic member 252 are comprised with elastic bodies, such as a coil spring, natural rubber, synthetic rubber, and silicone, and are arrange | positioned by making the elastic deformation direction into an up-down direction. The first telescopic shaft 154 and the second telescopic shaft 254 have a structure that can expand and contract only in the vertical direction.

  The second movable mass 200 is provided on the ground G via the second pedestal 220 and the second connecting portion 250, and the first movable mass 100 is connected to the first pedestal 120 and the first connected on the second movable mass 200. Part 150 is provided.

  Specifically, the lower end part of the second elastic member 252 and the lower end part of the second telescopic shaft 254 constituting the second connecting part 250 are attached to the second frame 220 provided on the ground G. And the 2nd movable mass 200 is attached to the upper end part of the 2nd elastic member 252 which comprises the 2nd connection part 250, and the upper end part of the 2nd expansion-contraction shaft 254, and the 2nd movable mass 200 can vibrate up and down. It is supported.

  The first pedestal 120 is bolted to the upper surface of the second movable mass 200, and the lower end of the first elastic member 152 and the lower end of the first telescopic shaft 154 constituting the first connecting portion 150 are connected to the first pedestal 120. Is attached. And the 1st movable mass 100 is attached to the upper end part of the 1st elastic member 152 which comprises the 1st connection part 150, and the upper end part of the 1st expansion-contraction shaft 154, and the 1st movable mass 100 can vibrate up and down. It is supported.

  Since the first telescopic shaft 154 and the second telescopic shaft 254 can expand and contract only in the vertical direction, the first movable mass 100 and the second movable mass 200 are prevented from vibrating in directions other than the vertical direction.

  The vibration damping device 10 shown in FIG. 1 having such a configuration has a two-mass system (two degrees of freedom) in which a first movable mass 100 and a second movable mass 200 are mechanically connected in series as shown in FIG. (Vibration system) vibration model.

  As shown in FIG. 8, the vibration exciter 400 is controlled by an electrically connected control device 420. The ground G is provided with an acceleration sensor 410, and the acceleration sensor 410 is electrically connected to the control device 420.

  The vibration exciter 400 is configured to vibrate the first movable mass 100 in the vertical direction. The control device 420 vibrates the first movable mass 100 and the second movable mass 200 connected to the first movable mass 100 with the shaker 400 so as to vibrate in the opposite phase to the ground G. Thereby, a damping force (inertial force) is generated in the first movable mass 100 and the second movable mass 200, and the vibration of the ground G is canceled and reduced (vibration of the ground G is suppressed).

  The control device 420 connected to the shaker 400 is configured by an electric circuit having a feedback circuit. Then, the control device 420 adds the excitation device 400 so that the excitation force (vibration suppression force) of the first movable mass 100 and the second movable mass 200 is amplified according to the acceleration (vibration acceleration) of the ground G. The vibration force (control force) is feedback controlled.

  Specifically, the acceleration (acceleration information) of the ground G detected by the acceleration sensor 410 is input to the control device 420. The control device 420 obtains the excitation force (control force) of the shaker 400 based on the input acceleration, and vibrates the ground G to the shaker 400 with the obtained excitation force (control force). Control signal to be generated and output to the vibration exciter 400. And based on this control signal, when the vibration exciter 400 vibrates the 1st movable mass 100, the damping force of the 1st movable mass 100 and the 2nd movable mass 200 is amplified. .

  Note that a known control method can be used for feedback control in which the control device 420 controls the shaker 400. For example, a modern control theory such as classic PID control, frequency shaping filter, or H∞ control (H-infinity Control) can be used.

  Here, when the ground G is vibrated in the vertical direction by the vibration control device 10, the vibration spreading through the ground G includes a horizontal component in addition to the vertical component. And the direction of vibration of the ground G to be reduced includes not only the vertical direction but also the horizontal direction. For example, the horizontal component of vibration generated mainly by vertical vibration by a heavy machine at a construction site may be amplified in resonance with the natural frequency in the horizontal direction of a building near the construction site. In such a case, the acceleration sensor installed on the ground G detects horizontal vibration, and the vibration damping device 10 vibrates the ground G in the vertical direction so that the horizontal vibration of the ground G is reduced. To control.

<Action and effect>
Next, the operation and effect of this embodiment will be described.

  As described above, since the vibration damping device 10 according to the present embodiment is configured by a two-mass point system (a vibration system with two degrees of freedom), a primary peak (primary natural frequency) and a secondary peak (secondary eigen frequency). Frequency), the frequency range in which the damping force of the first movable mass 100 and the second movable mass 200 is amplified is widened, and the frequency band in which the excitation force can be amplified is widened (see FIG. 2). ).

  Here, as shown in FIG. 8, the mass of the first movable mass 100 of the vibration damping device 10 of the present embodiment is M1, the mass of the second movable mass 200 is M2, and the mass of the adjustment mass 300 per sheet is m3. The elastic coefficient of the first elastic member 152 is K1, and the elastic coefficient of the second elastic member is K2.

  FIG. 2 shows the effect of amplifying the vibration force of the vibration exciter 400 to the ground G (amplification factor of the vibration force), the primary peak (primary natural frequency) fA, and the secondary peak (secondary natural frequency). 5 is a graph showing the relationship between (frequency) fB and the mass ratio μ (= M1 / M2) between the mass M1 of the first movable mass 100 and the mass M2 of the second movable mass 200. In the figure, Case 1 represents the case of μ = 0.05, Case 2 represents the case of μ = 0.1, Case 3, and μ = 0.2.

  From the graph of FIG. 2, as the mass ratio μ increases, the primary peak (primary natural frequency) fA and the secondary peak (secondary natural frequency) fB are separated, and a wider band can be achieved. It can be seen that the minimum magnification of the amplification magnification between the peak and the secondary peak fB decreases.

  When vibration in construction work such as new construction or dismantling work becomes a problem, the primary peak fA is reduced by reducing the damping force because of changes in the type of heavy machinery or the frequency of vibration generated by the operator's operation. The ability to easily adjust the primary peak fA or the secondary peak fB to the dominant frequency, which is a problem in the field, while maintaining the damping force, rather than the wide band effect that widens the gap between the primary peak fB and the secondary peak fB Is often useful.

  Next, adjustment of the primary peak (primary natural frequency) fA in the vibration damping device 10 of this embodiment will be described. As described above, in the vibration damping device 10 of the present embodiment, the adjustment mass 300 of 6 kg (m3) per piece that can be transported by human power is bolted to the four corners (each corner) of the first movable mass 100. It has a structure.

  3, 4, and 5, each of Case 1 (μ = 0.05), Case 2 (μ = 0.1), and Case 3 (μ = 0.2) has no adjustment mass 300 (0 sheets). In addition, four adjustment masses 300 (m3 × 4 = + 24 kgf), one in each corner, are bolted, and eight adjustment masses 300 (m3 × 8 = + 48 kgf), two in each corner, are bolted. The excitation power amplification magnification of each of the cases is shown.

The mass M1 of the first movable mass 100 and the mass M2 of the second movable mass 200 are:
Case 1 (μ = 0.05) is M1 = 120 kg, M2 = 2400 kg
Case 2 (μ = 0.1) is M1 = 240 kg, M2 = 2400 kg
Case 3 (μ = 0.2) is M1 = 480 kg, M2 = 2400 kg
It is.

  As shown in FIG. 3, in Case 1 (μ = 0.05), when a total of four adjustment masses 300 (m3 × 4 = + 24 kgf) are bolted to each corner, the primary peak fA is 5.63 Hz. In the case where a total of eight adjustment masses 300 (m3 × 8 = + 48 kgf) are bolted to two corners, the primary peak fA is changed from 5.63 Hz to 5.00 Hz.

  As shown in FIG. 4, in Case 2 (μ = 0.10), when a total of four adjustment masses 300 (m3 × 4 = + 24 kgf) are bolted to each corner, the primary peak fA is 5.30 Hz. When the adjustment mass 300 of 8 pieces (m3 × 8 = + 48 kgf) in total is bolted to two corners, the primary peak fA is changed from 5.30 Hz to 5.00 Hz.

  As shown in FIG. 5, in Case 3 (μ = 0.20), when the adjustment masses 300 in total (four by m3 × 4 = + 24 kgf) are bolted one by one in the four corners, the primary peak fA is 5.00 Hz. In the case where a total of eight adjustment masses 300 (m3 × 8 = + 48 kgf) are bolted to two corners, the primary peak fA is changed from 5.00 Hz to 4.90 Hz.

  In this way, by adjusting the mass by bolting the adjustment mass 300 of 6 kg (m3) per piece that can be transported by hand to the corner of the first movable mass 100, the primary peak (primary natural frequency) is mainly adjusted. ) FA can be changed (adjusted). That is, the primary peak fA can be easily changed (adjusted) to the dominant frequency that is a problem at the site. As shown in each figure, by adding the adjustment mass 300, the secondary peak (secondary natural frequency) fB is also changed, but the amount of change is smaller than that of the primary peak.

  As shown in FIG. 3, a total of eight adjustment masses 300 (m3 × 8 = + 48 kgf) are bolted to the four corners of the first movable mass 100 of Case 1 (μ = 0.05), and the primary peak fA is 5 When the frequency is changed to 0.000 Hz, since the minimum value of the amplification factor between the primary peak fA and the secondary peak fB is 10 times, there is no adjustment mass 300 for Case 2 (μ = 0.1) (FIG. 2). The damping force equivalent to that of the reference) is secured.

  Note that the smaller the μ = M1 / M2, the larger the amount of change in the primary peak (primary natural frequency) fA by bolting the adjustment mass 300. Therefore, from the viewpoint of ensuring a large adjustment amount (change amount) of the primary peak (primary natural frequency) fA at the construction site, the mass ratio μ is:

0.01 ≦ μ ≦ 0.1
Is desirable (FIG. 4).
Furthermore,
0.01 ≦ μ ≦ 0.05
Is more desirable (FIG. 3).

  In the vibration damping device 10 shown in FIG. 1, M1 is 120 kg, M2 is 2632 kg, and μ = 0.045 in the state without the adjustment mass 300. Therefore, it is almost the same as Case 1 (μ = 0.05). Further, the excitation force of the shaker 400 is 30 kgf.

  Therefore, if a total of eight adjustment masses 300 (m3 × 8 = + 48 kgf) are bolted to the four corners of the first movable mass 100 of the vibration damping device 10 of FIG. 1 as shown in FIG. The minimum value of the amplification factor between the peak fA and the secondary peak fB is about 10 times. Therefore, the minimum value between the primary peak fA and the secondary peak fB of the amplified damping force is 300 kgf. That is, the vibration of the ground G having the dominant frequency between the primary peak fA and the secondary peak fB can be suppressed (reduced) with a damping force of 300 kf or more.

  Next, when the elastic coefficient K1 of the first elastic member 152 constituting the first connecting portion 150 that connects the first movable mass 100 and the second movable mass 200 is changed, the secondary peak (secondary intrinsic) is mainly used. The change (adjustment) of the frequency fB will be described.

  In FIG. 6, when the elastic coefficient K2 of the first elastic member 152 is increased by Case 1 (μ = 0.05), specifically, the elastic coefficient K1 is 1.0 times, 1.4 times, 2.0 The excitation force amplification magnification in the case of double is shown.

  It can be seen from the graph of FIG. 6 that the secondary peak fB mainly changes by changing the elastic coefficient K2 of the first elastic member 152. In this example (FIG. 6), the adjustment mass 300 is not bolted (the adjustment mass 300 is 0 (zero)), but the adjustment mass 300 may be bolted.

  Therefore, the primary peak (primary natural frequency) fA can be mainly adjusted by adjusting the number of the adjustment masses 300, and the second is mainly obtained by exchanging the first elastic member 152 and adjusting the elastic coefficient K2. This can be done by adjusting the next peak (secondary natural frequency) fB. That is, the primary peak and the secondary peak can be freely adjusted by adjusting the number of bolts to be fastened with the bolts of the adjustment mass 300 and replacing the first elastic member 152.

  Since the mass of the first movable mass 100 becomes relatively light with respect to the second movable mass 200 as μ = M1 / M2 is decreased to increase the amount of change in the primary peak fA, the first movable mass It becomes easy to lift 100, and replacement of the first elastic member 152 is easy.

  For example, in the case of the vibration damping device 10 shown in FIG. 1, the first movable mass 100 is 120 kg as described above, and can be lifted with a small jack or the like without using a heavy machine. It is easy to replace 152.

  Next, a case where a plurality of vibration control devices 10 are installed will be described. Specifically, although it is the vibration damping device 10 of the same structure, adjusting the primary peak fA and the secondary peak fB to be different, and installing two units, further widening the range and increasing the excitation force A description will be given of what can be achieved.

  As an example, a vibration damping device (μ = 0.05) having the same structure is used. One is a vibration damping device [Case 1 (+48)] in which eight adjustment masses 300 (48 kg) are bolted, and the other has an elastic coefficient of 1. The damping device [Casa1 (K1 × 1.4)] is set to 4 times.

  [HMD × 2 units] in the graph of FIG. 7 indicates the amplification factor of the excitation force obtained by both [Case 1 (+48)] and [Casa 1 (K1 × 1.4)]. This [HMD × 2 units] has a total of four peaks (natural vibrations) of two primary peaks fA and secondary peaks fB of [Case1 (+48)] and [Casa1 (K1 × 1.4)], respectively. A wide band. In addition, since the excitation force is a total value of each, the minimum amplification factor between the four peaks (natural frequencies) is 20 times, and a large excitation force is exhibited.

  Note that [HMD × 2 units] in FIG. 7 is widened to the same extent as [Case 3 (μ = 0.2)] in FIG. However, if two [Case 3 (μ = 0.2)] of FIG. 2 are installed, the minimum amplification magnification is 5 × 2 = 10 times. Thus, the minimum amplification factor is 20 times, which is preferable.

  In this way, two control devices to which the present invention to which the adjustment mass 300 is detachable and μ is applied are adjusted so that the primary peak fA and the secondary peak fB are different, and two control devices are installed. As a result, it is possible to further widen the range and increase the excitation force.

  In the above example, one is a damping device [Case 1 (+48)] in which eight adjustment masses 300 (48 kg) are bolted, and the other is a damping device [Casa 1 (K1 × 1.4)], but is not limited thereto. The adjustment mass 300 may be bolted to the vibration damping device having the other elastic coefficient of 1.4 times. That is, the primary peak fA and the secondary peak fB may be adjusted as appropriate according to the dominant frequency of the ground G. Further, three or more vibration damping devices that appropriately adjust the primary peak fA and the secondary peak fB may be installed.

<Others>
The present invention is not limited to the above embodiment.

  For example, in the present embodiment, the first movable mass 100 is vibrated by the vibrator 400 provided on the upper portion of the first movable mass 100, but the present invention is not limited to this. For example, as shown in FIG. 9, an actuator 450 that expands and contracts in the vertical direction is provided between the first movable mass 100 and the second movable mass 200, and the first movable mass 100 is vibrated by the expansion and contraction of the actuator 450. Also good.

  Further, for example, in the above embodiment, the first movable mass 100 and the second movable mass 200 are two mass point system (vibration system with two degrees of freedom) in which the first movable mass 100 and the second movable mass 200 are mechanically connected in series. It is not limited to this. It may be a multi-mass system damping device in which three or more movable masses are mechanically connected in series.

  In the case of a multi-mass point system, the smaller movable mass among adjacent movable masses is vibrated as a first movable mass, and an adjustment mass having a smaller mass than the first movable mass is provided in the first movable mass. Note that the movable mass having the smallest mass among the plurality of movable masses does not necessarily have to be the first movable mass. Of the adjacent movable masses, the smaller mass may be the first movable mass.

  In the above embodiment, the vibration body that the vibration damping device to which the present invention is applied reduces (vibrates) the vibration is the ground G in which vibration is generated due to construction work such as new construction work or dismantling work. However, it is not limited to this. For example, the vibrating body may be a slab that is vibrated by an equipment machine such as a motor or a pump.

  Needless to say, the present invention can be implemented in various modes without departing from the scope of the present invention.

DESCRIPTION OF SYMBOLS 10 Damping apparatus 100 1st movable mass 152 1st elastic member 200 2nd movable mass 252 2nd elastic member 300 Adjustment mass 400 Exciter (an example of an excitation means)
450 Actuator (Example of vibration means)

Claims (3)

A plurality of movable masses connected in series with an elastic member;
Vibration means for exciting the first movable mass having a smaller mass among the adjacent movable masses;
The first movable mass is provided with an adjustable mass, and the adjustment mass is smaller in mass than the first movable mass,
Equipped with a,
The plurality of movable masses are connected in series in the vertical direction and configured to vibrate in the vertical direction,
The vibration means is provided on the top of the first movable mass.
Damping device. When the mass ratio between the mass of the second movable mass having the larger mass among the adjacent movable masses and the mass of the first movable mass is μ,
0.01 ≦ μ ≦ 0.05
Is set to be
The vibration damping device according to claim 1.   The first movable mass is composed of a rectangular metal plate in plan view,
  The vibration means is provided at a central portion of the upper portion of the first movable mass in plan view,
  The adjustment mass is bolted to the upper corner of the first movable mass in plan view,
  The vibration damping device according to claim 1 or 2.

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