JP2021121766A - Vibration damping device - Google Patents

Abstract

To provide a vibration damping device capable of efficiently damping vibration of an oscillator even in a case where am amplitude of the oscillator is relatively small.SOLUTION: A vibration damping device 1 having a configuration in which a mass body 4 after an initial velocity is added maintains rotation in one direction by an external force transmitted from an oscillator 7, has: a displacement unit in which a displacement expansion mechanism 8 is arranged between the oscillator 7 and a rotational shaft 3, and the displacement expansion mechanism 8 allows the rotational shaft 3 to be displaced with respect to the oscillator 7 in a direction parallel to the vibration direction of the oscillator 7; and a restoration unit that generates restoration force of returning the rotational shaft 3 moved by this displacement unit to a predetermined initial position.SELECTED DRAWING: Figure 1

Description

The present invention relates to a vibration damping device that is attached to a vibrating body to suppress the vibration of the vibrating body. Specifically, the present invention efficiently suppresses the vibration of the vibrating body even when the amplitude of the vibrating body is relatively small. It is about a vibration damping device that can be used.

The applicant has already proposed a vibration damping device that can automatically suppress the vibration of a vibrating body without installing a plurality of sensors or performing complicated control (see, for example, Patent Document 1). Patent Document 1 proposes a vibration damping device including a mass body that can freely rotate around a rotation axis and an activation mechanism that gives the mass body the initial velocity of rotational motion. Since the mass body that has started the rotational movement by the activation mechanism automatically synchronizes with the vibration of the vibrating body and maintains its rotation in one direction, the vibration damping device can obtain a vibration damping effect.

In the vibration damping device described in Patent Document 1, the mass body maintains its rotation by the vibration external force in the horizontal direction transmitted from the vibrating body to the rotating shaft. The applicant has experimentally found that if the amplitude of the vibrating body is too small, the mass body cannot maintain its rotation. That is, it was discovered that when the amplitude of the vibrating body is smaller than a predetermined value, the mass body given the initial velocity by the starting mechanism then stops without being able to maintain synchronous rotation due to the rotational resistance of the bearing or the like.

Japanese Patent Application Laid-Open No. 2013-50155

The present invention has been made in view of the above problems, and an object of the present invention is to provide a vibration damping device capable of efficiently suppressing the vibration of a vibrating body even when the amplitude of the vibrating body is relatively small. ..

The vibration damping device for achieving the above object is from a rotating shaft extending with a direction perpendicular to the vibrating direction of the vibrating body as an axial direction, and a rotating shaft installed on the rotating shaft from the rotation center of the rotating shaft. It is provided with a mass body having a center of gravity at a distant position and an activation mechanism that stops after adding the initial speed of rotational motion about the rotation axis to the mass body, and the mass body is transmitted from the vibrating body. A vibration damping device having a configuration for maintaining rotation in one direction by an external force is provided with a displacement expanding mechanism arranged between the vibrating body and the rotating shaft, and the displacement expanding mechanism is the vibrating body. On the other hand, a displacement portion that allows the rotation axis to be displaced in a direction parallel to the vibration direction of the vibrating body and a restoration force that returns the rotation axis moved by the displacement portion to a predetermined initial position are generated. It is characterized by having a part.

According to the present invention, the amplitude of the rotating shaft and the mass body can be made larger than the amplitude of the vibrating body by the displacement expanding mechanism. Since the amplitude of the rotating shaft and the mass body can be amplified, the vibration damping device can easily maintain the rotation of the mass body even when the amplitude of the vibrating body is small, and the vibration of the vibrating body can be efficiently suppressed.

It is explanatory drawing which illustrates the vibration damping device of this invention in a perspective view. It is explanatory drawing which illustrates the operating state of the vibration damping device of FIG. It is a graph which illustrates the state of vibration of a vibrating body and a rotating shaft. It is explanatory drawing which illustrates the modification of the vibration damping device of FIG. It is explanatory drawing which illustrates the operating state of the vibration damping device of FIG. It is a graph which illustrates the relationship between the frequency and the amplitude in a vibrating body. It is explanatory drawing which illustrates the modification of the displacement expansion mechanism. It is explanatory drawing which illustrates the modification of the displacement expansion mechanism. It is explanatory drawing which illustrates the modification of the displacement expansion mechanism. It is explanatory drawing which illustrates the operation of the adjustment part. It is a graph which illustrates the state of vibration of a vibrating body and a rotating shaft. It is explanatory drawing which illustrates the modification of the displacement expansion mechanism of FIG.

Hereinafter, the vibration damping device of the present invention will be described based on the embodiment shown in the figure. In the figure, the first direction in the horizontal plane is indicated by an arrow x, the second direction crossing the first direction at a right angle is indicated by an arrow y, and the vertical direction is indicated by an arrow z.

As illustrated in FIG. 1, the vibration damping device 1 of the present invention is fixed to a flat bottom plate 2 parallel to a horizontal plane, a rotating shaft 3 erected on the upper surface of the bottom plate 2, and the rotating shaft 3. It includes a mass body 4 and a starting mechanism 5 that is connected to the rotating shaft 3 and applies a rotational force to the rotating shaft 3. In this embodiment, a part of the rotating shaft 3 and the mass body 4 are arranged in a case 6 which is cylindrical and has a cavity inside. In FIG. 1, the case 6 is shown by a broken line for explanation. Case 6 is not an essential requirement of the present invention. The vibration damping device 1 may be configured not to include the case 6.

The bottom plate 2 is arranged so as to be parallel to the horizontal plane formed in the first direction x and the second direction y.

The rotating shaft 3 is extended so that the axial direction is perpendicular to the horizontal plane of the bottom plate 2. The rotating shaft 3 is installed on the bottom plate 2 and the case 6 via, for example, a ball bearing. The rotating shaft 3 is installed on the bottom plate 2 or the like in a state of being rotatable about the central shaft thereof.

In this embodiment, the mass body 4 is formed in a fan shape in a plan view. The center of gravity G of the mass body 4 is located at a position separated in a direction perpendicular to the axial direction of the rotating shaft 3. The shape of the mass body 4 is not limited to the above, and may be any shape as long as it has a center of gravity G at a position away from the rotation center of the rotation shaft 3, and may be formed of, for example, a rectangular parallelepiped or a sphere. The mass body 4 is fixed to the rotating shaft 3 and is configured to be rotatable around the central axis of the rotating shaft 3 together with the rotating shaft 3.

The starting mechanism 5 can be composed of, for example, an electric motor, a hydraulic motor, or the like. The starting mechanism 5 has a configuration in which the rotating shaft 3 is stopped after being added with the initial velocity of the rotational motion for rotating the rotating shaft 3 around its central axis. The starting mechanism 5 may include, for example, an electric motor connected to the rotating shaft 3 and a clutch for releasing the connection between the electric motor and the rotating shaft 3 after applying the initial speed of the rotational motion to the rotating shaft 3. The rotating shaft 3 to which the initial velocity of the rotational motion is added by the starting mechanism 5 freely rotates around the central axis of the rotating shaft 3 together with the mass body 4. It can be said that the starting mechanism 5 indirectly adds the initial velocity of the rotational motion to the mass body 4 via the rotating shaft 3.

In this embodiment, the starting mechanism 5 is installed above the rotating shaft 3. At this time, the activation mechanism 5 is installed in the case 6. The present invention is not limited to this configuration. The starting mechanism 5 may be installed below the rotating shaft 3. At this time, the starting mechanism 5 may be installed on the bottom plate 2.

The mass body 4 may be configured to be rotatable around the rotation shaft 3 with respect to the rotation shaft 3. That is, the rotation shaft 3 may be fixed to the case 6, and only the mass body 4 may rotate around the central axis of the rotation shaft 3. In this case, the activation mechanism 5 is configured to directly add the initial velocity of the rotational motion to the mass body 4. For example, the starting mechanism 5 can be configured by an air compressor or the like that injects air, and the initial velocity of the rotational motion can be added to the mass body 4 by the air injected by the air compressor.

The vibration damping device 1 is installed on the vibrating body 7. In the present specification, the vibrating body 7 is a general term for vibration sources that generate vibrations such as a marine diesel engine, a turbine for power generation, and a washing machine, or floor members and structures that vibrate by transmitting vibrations from these vibration sources. It is a concept to do.

The vibration damping device 1 includes a displacement expanding mechanism 8 installed between the vibrating body 7 and the rotating shaft 3. In this embodiment, the displacement expanding mechanism 8 includes a contact plate 9 that is in direct contact with the vibrating body 7 and is fixed to the vibrating body 7, and a plurality of leaf springs 10 arranged between the contact plate 9 and the bottom plate 2. It has. Leaf springs 10 are installed at the four corners of the bottom plate 2 and the contact plate 9 which are formed in a quadrangular shape in a plan view. The contact plate 9 is not an essential requirement in the present invention. The leaf spring 10 may be directly attached to the vibrating body 7 without using the contact plate 9.

The leaf spring 10 has a plane parallel to a plane composed of the second direction y and the vertical direction z, and is arranged in a state where the first direction x is the thickness direction. The leaf spring 10 is configured to be deformable along the first direction x. The leaf spring 10 allows the bottom plate 2 and the rotating shaft 3 to be displaced along the first direction x.

The configuration of the displacement expanding mechanism 8 is not limited to the above. A displacement portion that allows the rotating shaft 3 to be displaced in a direction parallel to the vibration direction of the vibrating body 7 with respect to the vibrating body 7, and a restoring force that returns the rotating shaft 3 that moves by this displacement portion to a predetermined initial position. The displacement expanding mechanism 8 may have a restoring portion to be generated. In this embodiment, the leaf spring 10 exerts the functions of both the displacement portion and the restoration portion of the displacement expansion mechanism 8. In the present specification, the initial position is the position of the vibrating body 7, the bottom plate 2, and the rotating shaft 3 in a state where the vibrating body 7 is not vibrated and the mass body 4 is stopped without performing rotational motion. To say.

When the marine diesel engine or the like, which is the vibrating body 7, is started and vibration is generated, the vibration damping device 1 installed in advance in the vibrating body 7 is operated. First, the vibration damping device 1 adds the initial velocity of the rotational motion to the mass body 4 by the activation mechanism 5. Since the starting mechanism 5 is then stopped, the mass body 4 freely rotates about the rotation shaft 3. The rotating shaft 3 reciprocates along the first direction x due to the vibration of the vibrating body 7 along the first direction x. An external force is generated on the mass body 4 that is rotating due to the reciprocating motion of the rotating shaft 3. Due to the influence of this external force, the rotation speed (frequency) of the mass body 4 approaches the frequency of the vibrating body 7, and finally the frequencies of the mass body 4 and the vibrating body 7 become equal. That is, the rotation of the mass body 4 is synchronized with the vibration of the vibrating body 7. The mass body 4 maintains a rotational motion in one direction by an external force transmitted from the vibrating body 7.

The rotational motion of the mass body 4 is damped by the frictional resistance of the bearing of the rotating shaft 3, but this damping is compensated by the external force transmitted from the vibrating body 7. Therefore, while the vibrating body 7 continues to vibrate, the mass body 4 keeps rotating.

FIG. 2 illustrates a state in which the mass body 4 is rotating in synchronization with the vibration of the vibrating body 7. In FIG. 2, for the sake of explanation, the center position P1 of the rotation axis 3 and the center position P2 of the contact plate 9 in the first direction x are shown by a alternate long and short dash line. Further, the position of the center of the rotating shaft 3 and the contact plate 9 when the vibrating body 7 is stopped without vibrating and the mass body 4 is stopped without rotating is set as the initial position P0 and is a dashed line. Shown. The vibrating body 7 vibrates along the first direction x due to the external vibration force with respect to the initial position P0, and the rotating shaft 3 vibrates along the first direction x with the vibration of the vibrating body 7.

FIG. 2 shows a state in which the vibration external force F acting on the vibrating body 7 is generated to the right in FIG. When the vibrating body 7 is, for example, a marine diesel engine, vibration due to the reciprocating motion of a plurality of pistons acts on the vibrating body 7 as an external vibration force F. It is preferable to operate the vibration damping device 1 at a frequency higher than the primary resonance point in the entire vibration system including the vibration damping device 1 and the vibrating body 7. When the vibrating body 7 vibrates at a frequency higher than this primary resonance point, the direction in which the external vibration force F acts and the direction in which the vibrating body 7, the rotating shaft 3, and the mass body 4 are located with respect to the initial position P0. Is in the opposite direction.

At the moment when the external vibration force F acts to the right in FIG. 2 and the magnitude of the external vibration force F becomes maximum, the contact plate 9 fixed to the vibrating body 7 is at the position P2 to the left of the initial position P0. Similarly, the bottom plate 2 and the rotating shaft 3 are located at the left position P1 of the initial position P0. In the direction along the first direction x, the direction in which the external vibration force F acts and the direction in which the vibrating body 7 and the rotating shaft 3 are displaced are opposite to each other.

When the vibration external force F is acting to the right, the center of gravity G of the mass body 4 is located to the left of the rotation axis 3. In the direction along the first direction x, the direction in which the external vibration force F acts and the direction in which the mass body 4 is located are opposite to each other. That is, the phase of the vibration on which the external vibration force F acts and the phase of the vibration of the vibrating body 7, the rotating shaft 3, and the mass body 4 are deviated by 180 degrees.

When the vibrating body 7 is vibrating, the bottom plate 2, the rotating shaft 3, and the mass body 4 have an inertial force, and the leaf spring 10 constituting the displacement expanding mechanism 8 has a restoring force. When the vibrating body 7 and the displacement expanding mechanism 8 vibrate due to the vibrating external force F, when the vibrating external force F acts to the left in FIG. 2, the vibrating body 7 and the mass body 4 are positioned to the right of the initial position P0. do. When the vibration damping device 1 is installed in the vibrating body 7 that vibrates in one degree of freedom system, the vibration system as a whole including the vibrating body 7 and the vibration damping device 1 becomes vibration in two degrees of freedom system.

When the vibrating body 7 vibrates at a frequency higher than the primary resonance point in the entire vibrating system, the direction of the vibration external force F acting on the vibrating body 7 and the direction of displacement of the rotating shaft 3 are opposite. Moreover, the amplitude of the rotating shaft 3 and the like is larger than the amplitude of the vibrating body 7 due to the leaf spring 10 of the displacement expanding mechanism 8.

FIG. 3 shows the vibration state of the vibrating body 7 and the rotating shaft 3. In FIG. 3, the solid line shows the vibration of the vibrating body 7, and the alternate long and short dash line shows the vibration of the rotating shaft 3 and the like. The vertical axis of the graph of FIG. 3 shows the vibration amplitude A (mm), and the horizontal axis shows the elapsed time T (sec). The position where the amplitude A in the graph of FIG. 3 becomes 0 is the initial position P0.

As shown by the solid line in FIG. 3, the amplitude of the vibrating body 7 is A0 in the state before the vibration damping device 1 is operated. When the initial velocity of the rotational motion is applied to the mass body 4 by the activation mechanism 5, the amplitude of the vibrating body 7 is suppressed to A1 by the rotational motion of the mass body 4 through a relatively short transient state.

As shown by the alternate long and short dash line in FIG. 3, the amplitude of the rotating shaft 3 and the like is A2. Since the displacement amount of the rotating shaft 3 and the like is amplified by the displacement expanding mechanism 8, the amplitude A2 of the rotating shaft 3 and the like is larger than the amplitude A1 of the vibrating body 7. Further, since there is resistance or the like when the displacement expanding mechanism 8 is displaced, there is a slight delay in the phase of the vibration of the rotating shaft 3 or the like with respect to the phase of the vibration of the vibrating body 7.

Even when the amplitude of the vibrating body 7 is so small that the rotational motion of the mass body 4 cannot be maintained by the conventional vibration damping device, this amplitude can be amplified by the displacement expanding mechanism 8. Since the amplitude of the rotation shaft 3 and the like is amplified, it becomes easy to maintain the rotational movement of the mass body 4. Even when the amplitude of the vibrating body 7 is relatively small, it is advantageous to obtain the vibration damping effect by the vibration damping device 1.

Although the vibration damping effect on the vibration in the first direction x has been described, the vibration damping device 1 can also obtain the vibration damping effect on the vibration in the second direction y. That is, it is possible to obtain a damping effect against vibrations in any direction in the horizontal plane formed in the first direction x and the second direction y. However, in this embodiment, since the displacement expanding mechanism 8 cannot amplify the displacement in the second direction y, only the vibration damping effect due to the rotation of the mass body 4 can be obtained for the vibration in the second direction y.

The direction of vibration that can be damped by the vibration damping device 1 is not limited to the horizontal direction. If the vibration damping device 1 is installed on the vibrating body 7 in a state where the axial direction of the rotating shaft 3 is in the horizontal direction, vibration in the vertical direction z of the vibrating body 7 can be suppressed.

As illustrated in FIG. 4, the displacement expanding mechanism 8 may include a columnar member 11 extending along the axial direction of the rotating shaft 3. Compared with the embodiment illustrated in FIG. 1, the rotating shaft 3 and the mass body 4 are located apart from the vibrating body 7 in the axial direction of the rotating shaft 3.

As illustrated in FIG. 5, the columnar member 11 is arranged between the rotating shaft 3 and the contact plate 9. The lower end of the columnar member 11 erected on the contact plate 9 is supported by the support portion 12. The support portion 12 supports the lower end of the columnar member 11 so that the columnar member 11 can tilt at least along the first direction x.

The upper end of the columnar member 11 supports the rotating shaft 3 via the connecting portion 13. In the axial direction of the rotating shaft 3, the connecting portion 13 supports a load such as the rotating shaft 3 or the mass body 4. On the other hand, the connecting portion 13 does not transmit the rotation of the rotating shaft 3 around the central axis to the columnar member 11. When the vibration damping device 1 includes the case 6, the connecting portion 13 may support the bottom surface of the case 6. The connecting portion 13 may have a configuration in which the inclination of the columnar member 11 is not transmitted to the rotating shaft 3 or the like. In this case, the axial direction of the rotating shaft 3 is kept constant, for example, in the vertical direction z, regardless of the inclination of the columnar member 11.

The intermediate portion of the columnar member 11 is supported by the bottom plate 2 via the intermediate support portion 14. The intermediate support portion 14 supports an intermediate portion of the columnar member 11 so that the columnar member 11 can tilt at least along the first direction x. Further, the intermediate support portion 14 allows the columnar member 11 to move in the axial direction thereof. The intermediate support portion 14 can be formed of, for example, a through hole formed in the bottom plate 2. In FIG. 5, for the sake of explanation, the position P1'at the center of the bottom plate 2 in the first direction x is shown by a alternate long and short dash line.

When the vibration external force F is generated to the right in FIG. 5, the contact plate 9 is at the left position P2 of the initial position P0. Similarly, the bottom plate 2 is also at the left position P1'of the initial position P0. The intermediate support portion 14 which is an intermediate portion is located on the left side of FIG. 5 as compared with the support portion 12 which is the lower end of the columnar member 11. Therefore, the upper end of the columnar member 11 is located further to the left of FIG. 5 than the position P1'.

The position P1 of the rotating shaft 3 arranged above the columnar member 11 is further to the left of FIG. 5 than the position P1'of the bottom plate 2. With the configuration in which the displacement expanding mechanism 8 includes the columnar member 11, the amount of displacement of the rotating shaft 3 can be further increased as compared with the embodiment illustrated in FIG. In the columnar member 11, the displacement amount of the rotating shaft 3 can be increased by increasing the distance between the connecting portion 13 and the intermediate supporting portion 14 with respect to the distance between the supporting portion 12 and the intermediate supporting portion 14.

The columnar member 11 may be formed of a member that has sufficient rigidity with respect to the weight of the rotating shaft 3, the mass body 4, and the like and does not deform with the tilt of the columnar member 11. Further, the columnar member 11 may have a structure that bends in a tilting direction. The amount of displacement of the rotating shaft 3 can be further increased by the configuration in which the columnar member 11 bends in the first direction x, for example.

The configuration of the displacement expanding mechanism 8 is not limited to the above. In addition to the configuration of the inverted pendulum in which the rotating shaft 3 and the mass body 4 are arranged at the upper ends of the columnar member 11 arranged so as to be tiltable, it is sufficient to have a configuration in which an intermediate portion of the columnar member 11 is supported. ..

In order to confirm the vibration damping effect of the vibration damping device 1 of the present invention, an experiment was conducted using the vibration damping device 1 of the embodiment illustrated in FIGS. 4 and 5. In the experiment, the vibrating body 7 was constructed by combining a motor to which a rotating shaft is connected and a weight having a center of gravity at a position away from the central axis of the rotating shaft. The frequency and amplitude of the vibrating body 7 can be changed according to the value of the rotation speed of the motor. In the experiment, the mass of the weight was 20 g.

The relationship between the frequency of the vibrating body 7 and the amplitude corresponding to this frequency is shown by a broken line in FIG. The vertical axis of the graph of FIG. 6 shows the amplitude A (mm) of the vibrating body 7, and the horizontal axis shows the frequency f (Hz) of the vibrating body 7. For example, when the rotation speed of the motor is adjusted so that the frequency f of the vibrating body 7 is 8 Hz, the amplitude A of the vibrating body 7 is 0.09 mm.

A vibration damping device 1 was installed on the vibrating body 7 to measure the vibration damping effect. In the experiment, the mass of the mass body 4 of the vibration damping device 1 was 16 g. First, as a comparative example, the displacement portion of the displacement expansion mechanism 8 was fixed to bring the vibration damping device 1 into the same state as when the displacement expansion mechanism 8 was not provided. In this vibration damping device 1, even if the starting mechanism 5 gives the mass body 4 the initial velocity of the rotational motion, the rotation of the mass body 4 is not maintained and the mass body 4 is stopped. That is, the rotation of the mass body 4 did not synchronize with the vibration of the vibrating body 7. When the amplitude A and the frequency f of the vibrating body 7 were in the states shown by the broken lines in FIG. 6, the rotation of the mass body 4 was not maintained in any case. It was found that the rotation of the mass body 4 was not maintained in the range where the amplitude A of the vibrating body 7 was 0.10 mm or less, and the vibration damping effect could not be obtained.

Next, the displacement portion was released from being fixed so that the displacement expansion mechanism 8 could function. In this vibration damping device 1, the mass body 4 given the initial velocity of the rotational motion by the activation mechanism 5 maintained rotation in one direction in synchronization with the vibration of the vibrating body 7. The amplitude A of the vibrating body 7 at this time is shown by the solid line in FIG. As is clear from FIG. 6, the amplitude of the vibrating body 7 was about 0.04 mm to 0.05 mm at any frequency f. It was found that the vibration damping device 1 can suppress the amplitude A of the vibrating body 7 by about half.

From the above experiment, it was found that the vibration damping device 1 provided with the displacement expanding mechanism 8 can obtain the vibration damping effect even when the amplitude of the vibrating body 7 is relatively small.

The displacement expanding mechanism 8 may have a configuration that allows the rotating shaft 3 and the mass body 4 to move along the vibration direction of the vibrating body 7, and the structure and the like thereof are not limited. As illustrated in FIG. 7, the displacement expansion mechanism 8 may be composed of laminated rubber 15 formed by alternately laminating a plurality of steel plates and rubber plates. The laminated rubber 15 can be arranged, for example, between the bottom plate 2 and the contact plate 9. In FIG. 7, for the sake of explanation, the rotating shaft 3 and the case 6 arranged on the upper surface of the bottom plate 2 are omitted.

The laminated rubber 15 has both a displacement portion that allows the bottom plate 2 to be displaced in the horizontal direction with respect to the contact plate 9 and a restoration portion that generates a restoring force that returns the position of the bottom plate 2 with respect to the contact plate 9 to the initial position P0. Demonstrate function. The laminated rubber 15 can be displaced in either the first direction x or the second direction y. Therefore, the vibration damping device 1 can amplify the displacement of the rotating shaft 3 and the like and obtain the vibration damping effect with respect to the vibration in any direction in the horizontal plane formed in the first direction x and the second direction y. ..

It is desirable that the damping of the laminated rubber 15 is relatively small. This is because the larger the damping, the more the phase of the vibration of the rotating shaft 3 and the like is delayed with respect to the phase of the vibration of the vibrating body 7. Specifically, it is desirable that the laminated rubber 15 is made of a rubber plate having a small damping ratio.

As illustrated in FIG. 8, the displacement expanding mechanism 8 may be composed of a plurality of round bars 15a. The round bars 15a are installed at the four corners of the bottom plate 2 and the contact plate 9 which are formed in a quadrangular shape in a plan view. The round bar 15a is arranged so that its axial direction is parallel to the axial direction of the rotating shaft 3. By bending, the round bar 15a exerts both functions of a displacement portion that allows the bottom plate 2 to be displaced with respect to the contact plate 9 and a restoration portion that generates a restoring force on the bottom plate 2.

Therefore, similarly to the laminated rubber 15, the vibration damping device 1 amplifies and controls the displacement of the rotating shaft 3 and the like with respect to vibrations in any direction in the plane composed of the first direction x and the second direction y. A vibration effect can be obtained. The number of round bars 15a is not limited to four. Further, the positions where the round bars 15a are arranged are not limited to the four corners of the bottom plate 2 and the like. The number of round bars 15a may be three or less, or five or more, as long as the bottom plate 2 is supported in a displaceable state along the vibration direction and a restoring force is generated.

As illustrated in FIG. 9, the displacement portion 8a of the displacement expansion mechanism 8 is composed of a pair of plates 16 stacked in the vertical direction z and a slider including a cylindrical roller 17 arranged between the plates 16. You may. In the displacement portion 8a, a plurality of cylindrical rollers 17 rotatably arranged in a state where the central axis is parallel to the first direction x are arranged between the upper plate 16a and the lower plate 16b. In FIG. 9, a part of the member hidden in the upper plate 16a is shown by a broken line for explanation.

The restoring portion 8b of the displacement expanding mechanism 8 may be configured by an air spring formed by enclosing a compressible fluid such as air in a cylinder. The air spring is arranged so as to be expandable and contractible along the second direction y. The restoration portion 8b is fixed to the displacement portion 8a by a fixing member 18 that connects one end of the cylinder and the upper plate 16a and a fixing member 18 that connects the other end of the cylinder and the lower plate 16b.

In the displacement expanding mechanism 8 illustrated in FIG. 9, the upper plate 16a moves in the second direction y on the plurality of rollers 17, so that the rotation shaft 3 and the like arranged on the upper surface of the upper plate 16a are displaced in the horizontal direction. Let me. When the air spring contracts or expands with the movement of the upper plate 16a, the restoring unit 8b generates a restoring force in the direction of returning the expansion and contraction.

When the vibration of the vibrating body 7 is determined in one direction such as the second direction y and does not change in the middle, the displacement expanding mechanism 8 illustrated in FIG. 9 can be adopted. The displacement expanding mechanism 8 illustrated in FIG. 9 tends to increase the displacement amount of the displacement portion 8a. Further, the restoration unit 8b can easily adjust the magnitude of the restoration force by changing the pressure of the enclosed gas or the like.

Two displacement expansion mechanisms 8 illustrated in FIG. 9 may be stacked and used. Specifically, the displacement expanding mechanism 8 displaceable in the second direction y and the displacement expanding mechanism 8 displaceable in the first direction x are laminated. According to this configuration, the displacement expanding mechanism 8 can be displaced in any direction in the horizontal plane.

The upper plate 16a may be composed of the bottom plate 2. Further, the lower plate 16b may be composed of the contact plate 9. The displacement expansion mechanism 8 can be configured to be relatively small.

The configuration of the displacement portion 8a is not limited to the above. Other structures may be adopted as long as the rotation shaft 3 and the like can be displaced along the vibration direction of the vibrating body 7. Similar to the embodiment illustrated in FIGS. 4 and 5, the columnar member 11 may be combined with the laminated rubber 15, the round bar 15a, or the slider. As a result, the columnar member 11 can be tilted not only in the direction along the first direction x but also in the direction along the second direction y.

Further, the configuration of the restoration unit 8b is not limited to the above. Other structures may be adopted as long as the displacement generated by the displacement portion 8a can be returned to the original position.

As illustrated in FIG. 10, the displacement expanding mechanism 8 may have an adjusting unit 19 for changing the magnitude of the restoring force of the restoring unit 8b. In this embodiment, the adjusting portion 19 is composed of adjusting screws for fixing the leaf spring 10 arranged so as to penetrate the bottom plate 2 to the bottom plate 2.

When the adjusting screw arranged on the side of the bottom plate 2 is loosened, the leaf spring 10 and the bottom plate 2 are released from being fixed, so that the bottom plate 2 can move with respect to the leaf spring 10 in the vertical direction z. It becomes. For example, after moving the bottom plate 2 downward, the adjusting screw is tightened to fix the bottom plate 2. As illustrated in FIG. 10, the length of the leaf spring 10 between the bottom plate 2 and the contact plate 9 is shortened. Therefore, the restoring force of the leaf spring 10 is increased.

Since the restoring force of the restoring unit 8b can be increased by the adjusting unit 19, the resonance frequency of the secondary mode of the entire vibration system including the vibration damping device 1 and the vibrating body 7 can be increased.

FIG. 11 shows the vibration damping effect of the vibration damping device 1 when the restoring force is adjusted to be relatively large by the adjusting unit 19 and when the restoring force is adjusted to be relatively small. The vertical axis of the graph of FIG. 11 shows the amplitude A (mm) of the vibrating body 7, and the horizontal axis shows the frequency f (Hz) of the vibrating body 7.

The broken line in FIG. 11 shows the relationship between the amplitude A and the frequency f of the vibrating body 7. The solid line in FIG. 11 shows the damping effect of the damping device 1 adjusted to have a relatively small restoring force. It can be seen that when the frequency f of the vibrating body 7 exceeds 15 Hz, the amplitude A of the vibrating body 7 becomes large, and it is difficult to obtain the vibration damping effect. It is considered that this is because the frequency f of the vibrating body 7 approaches the secondary resonance frequency of the entire vibration system.

The alternate long and short dash line in FIG. 11 shows the damping effect of the damping device 1 in which the restoring force is adjusted to be relatively large. It can be seen that the amplitude A of the vibrating body 7 is suppressed to a small extent until the frequency f of the vibrating body 7 approaches 30 Hz, and the vibration damping effect is obtained. By adjusting the restoring force by the adjusting unit 19, it becomes easy to obtain the vibration damping effect by the vibration damping device 1 even when the frequency of the vibrating body 7 is relatively high.

On the other hand, if the restoring force is made too large by the adjusting unit 19, the amount of displacement by the displacement unit 8a becomes small. Since the function of increasing the displacement amount of the rotating shaft 3 and the like is reduced, it becomes difficult to obtain the vibration damping effect when the frequency of the vibrating body 7 is relatively low.

When the adjusting portion 19 is combined in the embodiment illustrated in FIGS. 4 and 5, the closer the bottom plate 2 is to the contact plate 9, the larger the amount of displacement by the displacement portion 8a having the columnar member 11. Therefore, it becomes easy to obtain the vibration damping effect by the vibration damping device 1 in both the case where the frequency of the vibrating body 7 is relatively low and the case where the frequency is relatively high.

As illustrated in FIG. 12, the restoration unit 8b may be configured by an air spring, and the adjusting unit 19 may be configured by a device that adjusts the pressure of the air spring. The restoring force of the restoring unit 8b can be changed relatively easily by adjusting the pressure of the air spring.

The restoring force may be changed by the adjusting unit 19 while the vibration damping device 1 is operating to suppress the vibration. In this embodiment, the vibration damping device 1 comprises an acquisition unit 20 that directly or indirectly acquires the frequency f of the vibrating body 7, and a control unit 21 that controls the adjustment unit 19 according to the value acquired by the acquisition unit 20. I have. The control unit 21 is connected to the adjustment unit 19 and the acquisition unit 20 by signal lines, respectively. In FIG. 12, the signal line is shown by a chain double-dashed line for explanation.

In this embodiment, the acquisition unit 20 is fixed to the lower plate 16b. Since the lower plate 16b is directly installed on the vibrating body 7, it is advantageous for the acquisition unit 20 to accurately acquire the frequency of the vibrating body 7. The acquisition unit 20 can be configured by, for example, an acceleration sensor. The acquisition unit 20 is not limited to the acceleration sensor, and may have a configuration capable of acquiring the frequency of the vibrating body 7.

When the frequency acquired by the acquisition unit 20 is relatively low, the control unit 21 controls the adjustment unit 19 based on this frequency to maintain the restoring force in a relatively small state. For example, if the adjusting unit 19 removes gas from the cylinder of the restoring unit 8b, the restoring force can be easily reduced. Since the displacement amount of the displacement portion 8a can be increased as the restoring force is smaller, it becomes easier to obtain a vibration damping effect against vibration having a small amplitude.

When the frequency acquired by the acquisition unit 20 is relatively high, the control unit 21 controls the adjustment unit 19 based on this frequency to bring the restoring force into a relatively large state. For example, if the adjusting unit 19 supplies gas to the cylinder of the restoring unit 8b based on a command from the control unit 21, the restoring force of the restoring unit 8b can be easily increased. The larger the restoring force, the higher the secondary resonance frequency of the entire vibration system including the vibration damping device 1 and the vibrating body 7. Since the vibration system as a whole is less likely to resonate, the vibration damping device 1 makes it easier to obtain a vibration damping effect.

The control unit 21 controls to increase the restoring force when the frequency acquired by the acquisition unit 20 exceeds a predetermined threshold value and return the restoring force to the original state when the frequency becomes equal to or less than the threshold value. It may be configured to be performed by.

With the configuration in which the vibration damping device 1 includes the acquisition unit 20 and the control unit 21, vibration damping is efficiently performed for a vibrating body 7 whose frequency changes during vibration, such as a marine diesel engine. Can be done.

1 Vibration damping device 2 Bottom plate 3 Rotating shaft 4 Mass body 5 Starting mechanism 6 Case 7 Vibrating body 8 Displacement expansion mechanism 8a Displacement part 8b Restoring part 9 Contact plate 10 Leaf spring 11 Column member 12 Support part 13 Connecting part 14 Intermediate support part 15 Laminated rubber 15a Round bar 16 Plate 16a Upper plate 16b Lower plate 17 Roller 18 Fixing member 19 Adjusting unit 20 Acquiring unit 21 Control unit x 1st direction y 2nd direction z Vertical direction G Center of gravity F Vibration external force P0 Initial position P1 (Rotating axis) Position P1'(center of bottom plate) Position P2 (center of contact plate) Position A Magnitude A0 (Before vibration damping of vibrating body) Magnification A1 (After vibration damping of vibrating body) Magnification A2 (Rotation (Axis, etc.) amplitude f frequency

Claims (8)

A rotating shaft extending with a direction perpendicular to the vibration direction of the vibrating body as an axial direction, a mass body installed on the rotating shaft and having a center of gravity at a position away from the rotation center of the rotating shaft, and the rotation. It is equipped with a start mechanism that stops after adding the initial speed of rotational motion around the axis to the mass body.
In a vibration damping device having a configuration in which the mass body maintains rotation in one direction by an external force transmitted from the vibrating body.
It is provided with a displacement expanding mechanism arranged between the vibrating body and the rotating shaft.
The displacement expanding mechanism makes it possible to displace the rotating shaft with respect to the vibrating body in a direction parallel to the vibrating direction of the vibrating body, and a predetermined initial position of the rotating shaft moved by the displacement portion. A vibration damping device characterized by having a restoring unit that generates a restoring force for returning to a position. The vibration damping device according to claim 1, wherein the mass body has a configuration in which the mass body freely rotates about the rotation axis after an initial velocity is added to the activation mechanism. The first aspect of claim 1, wherein the starting mechanism includes an electric motor connected to the rotating shaft and a clutch that releases the connection between the electric motor and the rotating shaft after adding the initial speed of rotational motion to the mass body. Anti-vibration device. The vibration damping device according to any one of claims 1 to 3, wherein the displacement portion is configured to be displaceable only in a preset first direction. The displacement expanding mechanism includes a contact plate installed on the vibrating body, a bottom plate arranged between the contact plate and the rotating shaft, and a leaf spring arranged between the contact plate and the bottom plate. Is equipped with
The vibration damping device according to claim 4 , wherein the leaf spring has a configuration in which the bottom plate can be displaced with respect to the contact plate in a direction parallel to the vibration direction of the vibrating body. The displacement expanding mechanism includes a columnar member extending along the axial direction of the rotating shaft.
The columnar member, wherein the intermediate portion while being disposed between the rotary shaft and the contact plate be supported on the bottom plate, tiltably constructed claims vibration direction parallel to the direction of said vibrating body The vibration damping device according to 5. The vibration damping device according to any one of claims 1 to 6 , wherein the displacement expanding mechanism has an adjusting unit for changing the magnitude of the restoring force of the restoring unit. It includes an acquisition unit that acquires the frequency of the vibrating body and a control unit that controls the adjustment unit according to the value acquired by the acquisition unit.
The vibration damping device according to claim 7 , further comprising a configuration in which the adjusting unit changes the magnitude of the restoring force in response to a command from the control unit while the mass body is maintaining rotation.

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