JP2939235B1 - Dynamic vibration absorber - Google Patents

Abstract

An object of the present invention is to provide a dynamic vibration absorber having a simple structure, excellent portability, and excellent on-site operability. SOLUTION: A dynamic vibration absorber main body which is magnetically attracted to a vibrating body to be damped is provided, and a T-shaped lever having a horizontal axis is provided on the dynamic vibration absorber main body by a bearing so as to be angularly displaceable. The weight is detachably attached to the rod-shaped support of the lever. A tension spring is replaceably mounted between the support and the dynamic vibration absorber main body. Damping coefficient adjusting means for elastic friction contact is provided at the base end of the lever, and the degree of friction contact is adjusted by a screw.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dynamic vibration absorber that absorbs vibration of a vibrating body and damps the vibration.

[0002]

2. Description of the Related Art A hull block is manufactured by placing an outer plate on a receiving jig provided at intervals of 1 m on a surface plate (floor). In the case of a bent outer plate, a gap often occurs between the receiving jig and the outer plate due to a shape error due to a processing error, and when an operator walks on the outer plate or an object is carried into the outer plate. For example, the outer plate is likely to vibrate. In addition, the vibration of the surface plate caused by the traveling of the overhead crane in the factory or the like may cause disturbance, and the outer plate may cause a resonance phenomenon. As described above, when vibration occurs in the outer plate, work such as shape measurement of the outer plate is hindered. Therefore, in order to suppress the vibration of the outer plate, a dynamic vibration absorber that can be easily installed and set is required.

[0003] A typical prior art is disclosed in Japanese Patent Laid-Open No. 7-11343.
8 In this prior art, a weight that can move in the axial direction of the cantilever support rod is installed, and the spring constant is changed by moving the weight in the axial direction. However, in such a configuration, the variable range of the spring constant is relatively narrow, and the damping portion is not particularly provided, so that the vibration damping effect is provided only at a certain specific frequency, and the object vibrating at a plurality of vibration frequencies is used. Has no effect.

[0004] Another prior art is Japanese Patent Publication No. H8-16497. In this prior art, a fulcrum of a lever is pivotally attached to a support structure attached to a vibration system, the levers extend in opposite directions, and a weight is attached to a tip portion of the lever, and an action point is set. The lever is restrained by the damping mass, and a pair of the levers is provided. The damping mass is attached to the vibration system via a spring and a damper. Further, this prior art discloses a configuration using an air spring. In this prior art, the spring is fixed, but the weight is composed of upper and lower split blocks, and can be installed at any position according to the natural period of the vibration system. Further, the opening degree of the orifice can be changed in accordance with the natural period, and the attenuation rate can be changed. However, since the structure is relatively complicated and large, it is suitable for a vibration control device for a building or a bridge whose natural frequency is known in advance, but each time it is applied to a wide range of industrial fields, It is necessary to design and manufacture a dynamic vibration absorber, which is inferior in flexibility.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a simple structure, excellent portability, easy installation and adjustment, and a response and setting on site even when the vibration frequency of the object is unknown. It is to provide a dynamic vibration absorber that is easy.

[0006]

SUMMARY OF THE INVENTION The present invention provides a dynamic vibration absorber main body attached to a vibrating body, a lever, and a base end provided on the dynamic vibration absorber main body so as to be angularly displaceable about a horizontal axis. A lever having a rod-shaped support extending from the base end; a weight removably mounted on the support of the lever at a weight mounting position along the longitudinal direction of the support; a dynamic vibration absorber main body and a support. A spring interposed between the body and the spring, which is mounted at a spring mounting position along the longitudinal direction of the support, and frictionally contacts the proximal end of the lever on the side opposite to the support with respect to the horizontal axis, and Damping coefficient adjusting means provided on the main body so as to adjust the damping coefficient of the dynamic vibration absorber by screws, the base end of the lever has an arc-shaped contact surface centered on the horizontal axis, and a damping coefficient The adjusting means adjusts the pressure at which the contact surface comes into frictional contact. A dynamic vibration absorber, which is a adjustable by the screw.

According to the present invention, the lever is provided so as to be angularly displaceable by the bearing so as to be angularly displaceable about the horizontal horizontal axis, for example, about the horizontal axis, from the base end of the lever. A weight is removably mounted on the substantially vertically extending rod-shaped support at any weight mounting position, and one end of a tension spring is mounted at any desired spring mounting position, or one or more predetermined springs. The spring is mounted at the mounting position, and the other end of the spring is detachably mounted on the dynamic vibration absorber main body above the lever.

A damping coefficient adjusting means is provided at the base end of the lever, and the damping coefficient adjusting means comes into frictional contact with the base end of the lever, and the damping coefficient can be adjusted by a screw.

Such a configuration is relatively simple, can be miniaturized, is compact, and is excellent in portability. Moreover, it is easy to install and adjust, and can be used on site. Furthermore, even when the natural frequency of the vibrating body as an object is unknown and needs to be dealt with on site, it can be easily set and installed on site, and its operation is easy. Further according to this configuration,
It is realized at low cost.

[0010]

According to the invention, the proximal end of the lever has, for example, an arc-shaped contact surface which is at least partly part of a perfect circle centered on the horizontal horizontal axis. Thereby, the damping coefficient adjusting means can stably make frictional contact regardless of the angular position of the lever, and can realize a predetermined constant damping coefficient.

Further, according to the present invention, the damping coefficient adjusting means may include a bottomed cylindrical casing having an external thread, and an at least partially spherical contact part partially exposed from an open end of the casing and contacting the contact surface. Pieces and stored in the casing,
It has a compression spring interposed between the bottom of the casing and the contact piece, and the bottom screw of the casing is screwed to the internal screw formed on the dynamic vibration absorber main body.

According to the present invention, the bottomed cylindrical casing is screwed into the dynamic vibration absorber main body, and this casing is displaced in the vicinity of or away from the base end of the lever.
At least a partially spherical portion of the contact piece makes frictional contact with the proximal end, and the pressing force is applied by a compression spring. Thus, the damping coefficient can be easily adjusted.

Further, according to the present invention, the lever has an elongate base end extending perpendicularly to the support, the entire planar shape of the lever is formed in a T-shape, and the damping coefficient adjusting means is provided in the longitudinal direction of the base end. Are arranged at intervals.

According to the present invention, the lever is formed in a T-shape in its entire plane, so that a plurality of damping coefficient adjusting means are spaced along the horizontal axis at the base end thereof. A relatively large attenuation coefficient can be realized by disposing them at intervals.

According to the present invention, there is provided a dynamic vibration absorber as described above.
And the mass m of the vibrating body₁And the amplitude X of the vibrating body to be damped₁When
Vibration body static deflection X_stAnd the predetermined ratio X₁/ X _stWhen,
Vibration frequency ω of vibrator₁And the mass of the weight m
_TwoAnd the spring constant k of the spring_TwoAnd the longitudinal direction of the lever support
Determine the installation position of the weight and spring, and vibrate the dynamic vibration absorber.
Arranged near the antinode of body vibration and adjusted damping coefficient adjustment means
To minimize the amplitude of the vibrator.
This is a method of damping the vibrating body.

According to the present invention, a calculation is performed based on the mass m _{1 of the} vibrating body, the ratio X ₁ / X _st, and the vibration frequency ω ₁ of the vibrating body to obtain the mass m ₂ of the weight and the type of the spring. Therefore, it is possible to easily determine the spring constant k ₂ and the installation positions of the weight and the spring, and the operability on site is excellent.

[0018]

FIG. 1 is a perspective view showing an entire structure of a dynamic vibration absorber 56 according to an embodiment of the present invention. The dynamic vibration absorber main body 1 made of a material such as aluminum is entirely formed in a frame shape by a bottom plate 2, a pair of end plates 3, 4 and a ceiling plate 11. A pair of side plates 5 and 6 are fixed near the end plate 4 over the bottom plate 2 and the ceiling plate 11. The bottom plate 2 includes a plurality (for example, 3 in this embodiment) of permanent magnet pieces 7,
Vibrator 1 made of ferromagnetic material such as iron
0 (see FIG. 9 described later) by magnetic attraction.

FIG. 2 is a side view of the dynamic vibration absorber 56, and FIG.
Is a front view of the dynamic vibration absorber 56 as viewed from the end plate 4. The lever 12 has, for example, an elongated base 13 extending along a horizontal horizontal axis, and a rod-shaped support 14 extending perpendicularly to the base 13 from a central position in the longitudinal direction of the base 13. The entire planar shape of the lever 12 is T-shaped. The lever 12 may be made of a metal material such as iron or aluminum, and may be made of a cylindrical body having a circular section perpendicular to the axis. A screw hole 15 is formed in the support 14 of the lever 12 at regular intervals L1 along the length direction (the left-right direction in FIG. 2). The weight 16 shown in FIG. 4 is removably mounted on the support 14 at any desired weight mounting position. The weight 16 is composed of a pair of divided weight pieces 16a and 16b. Through holes 17 and 18 are formed in one weight piece 16a, and the other weight piece 16
In b, screw holes 19 and 20 are formed corresponding to the play holes 17 and 18, respectively. Hex Socket Head Cap Screws 21, 22
Are detachably screwed into the screw holes 19 through the through holes 17 and 18, respectively. Thus, the weight pieces 16a, 1
6b, the outer peripheral surface of the support 14 is sandwiched between the substantially semi-circular notches 23, 24 facing each other.
Removably attached to. Such a weight 16
A plurality of types having different masses m ₂ are prepared and selectively attached to the support 14.

Both ends in the longitudinal direction of the base end portion 13 are
6 is provided by bearings 25 and 26 so as to be angularly displaceable about a horizontal axis which is its longitudinal axis. This base end 13
Has an outer peripheral surface in the shape of a right cylinder with the axis 27 as the center.

FIG. 5 is a sectional view taken along line VV of FIG. The end plate 4 has a longitudinal direction of the base end 13 (FIG. 3).
The opening 29 extends along the left-right direction (the direction perpendicular to the plane of FIG. 5). The opening 29 is provided on the inner surface of the end plate 4.
, The mounting plate 30 is detachable by bolts 31,
Mounted. The mounting plate 30 is spaced apart in the longitudinal direction of the base end 13 (the left-right direction in FIG. 3) and the left and right target surfaces 3
A plurality (5 in total in this embodiment) of screw holes 33 are formed symmetrically about 2. The damping coefficient adjusting means 34 is screwed into each of the screw holes 33.

FIG. 6 is a cross-sectional view showing a part of the damping coefficient adjusting means 34, and FIG.
4 is a front view of FIG. The damping coefficient adjusting means 34 includes a bottomed cylindrical casing 35 made of a material such as a synthetic resin, a spherical contact piece 36, and a compression spring 37. An external screw 38 is engraved on the casing 35. The contact piece 36 is made of, for example, stainless steel. The contact piece 36 is partially exposed from the opening end 39 of the casing 35 outward (to the left in FIG. 6 and to the right in FIG. 5), and the contact surface 40 of the contact piece 36 The contact surface 41 of the thirteen end plate 4 is brought into contact with the spring 37 by the elastic force. Thus, the contact piece 36 comes into frictional contact with the base end 13. The center 42 of the contact piece 36 is
For example, it is arranged in a horizontal plane including the axis 27 of the base end portion 13. The spring 37 is interposed between the bottom 43 of the casing 35 and the contact piece 36. The bottom 43 of the casing 35
, A driver engaging groove 44 is formed facing the opposite side of the contact piece 36. Instead of the engaging groove 44, an engaging hole of a spanner may be formed. This allows the casing 3
5 is operated with a screwdriver or a spanner, and the casing 3
5 close to the proximal end 13 of the lever 12 along its axis /
As a result, the degree of frictional contact between the contact piece 36 and the contact surface 41 of the base end portion 13 can be individually adjusted.

Referring to FIG. 2 again, one end 48 of a tension spring 47 is detachably connected to a bolt 46 screwed into the screw hole 15 of the support 14. Also the ceiling plate 11, a plurality of screw holes 49 spaced equal distance L ₂ just above the support 14 is formed. This screw hole 49 has a bolt 5
0 is detachably screwed. The other end 51 of the tension spring 47 is detachably connected to the bolt 50. The screw holes 15 of the support 14 and the screw holes 49 of the ceiling plate 1 correspond to each other, and the interval L ₁ = L ₂ .

Mounting plates 52, 5 for supporting bearings 25, 26
3 is detachably attached to the side plates 5 and 6 by bolts 54.

FIG. 8 is a diagram for explaining the principle of the dynamic vibration absorber of the present invention. The dynamic vibration absorber is indicated by reference numeral 56.
The dynamic vibration absorber 56 basically includes the weight 16, the spring 47, and the damping coefficient adjusting means 34 which is a damper. The mass of the weight 16 is m ₂ . The spring constant of the spring 47 is k ₂ . The damping coefficient of the present dynamic vibration absorber of the damping coefficient adjusting means 34 is c ₂ . FIG. 9 is a simplified diagram of the dynamic vibration absorber 56. The spring 47 has a distance r from the axis 27 of the proximal end 13 of the lever 12.
Is removably connected to the position. The center of gravity of the weight 16 is a distance L from the axis 27 along the longitudinal direction of the support 14.
Having. Thus, a horizontal spring supporting pendulum is configured.

FIG. 10 is a simplified cross-sectional view of a part of the vibrating body 10. In shipbuilding factories, the bent skin of the ship is
The vibrating body 10 is made of, for example, iron, which is a ferromagnetic material. The vibrating body 10 is fixed to the surface plate 5 by the receiving jig 57.
8 supported. The static deflection X _st of the vibrating body 10 is the amount of deflection of the flat outer plate from the shortest receiving jig 57. In FIG. 8, the spring constant of the vibrating body 10 is represented by reference numeral k _1.
And its attenuation coefficient is denoted by c ₁ . The equations of motion of the vibration system in FIG. 8 are represented by Equations 1 and 2.

[0027]

(Equation 1)

FIG. 11 is a graph showing the experimental results of the present inventor. A thin line 60 indicates a vibration state of the vibrating body 10 when the present dynamic vibration absorber 56 is not provided, and a thick line 61 indicates a vibration state of the vibrating body 10 when the present dynamic vibration absorber 56 is used. 6 shows frequency characteristics. FIG. 11 (2) shows the impulse response of this system. When the dynamic vibration absorber 56 is not used, the vibration of the vibrating body 10 is indicated by a reference numeral 62.
Does not decay as indicated by. By using the dynamic vibration absorber 56 of the present invention, the vibration is rapidly damped as indicated by reference numeral 63. By installing the dynamic vibration absorber 56 on the vibrating body 10 in this manner, in a configuration in which the natural frequency of the dynamic vibration absorber 56 approximates the vibration frequency of the vibrating body 10 or the natural frequency, It can be understood that the vibrations can be attenuated.

In the dynamic vibration absorber 56, when a periodic external force Fsinωt acts on the main vibration system having the mass m ₁ and the spring constant k ₁ , the mass m ₂ , the spring constant k ₂ , and the viscous damping coefficient c The amplitude X ₁ of the main vibration system when the _two dynamic vibration absorbers 56 are installed is given by the following equation.

[0030]

(Equation 2)

FIG. 12 shows the amplitude ratio of the main mass when the damping ratio に 対 す る with respect to the forced frequency ratio ω / ω ₁ is changed. ζ = 0
In the case of (c ₂ = 0), a _two -degree-of-freedom system without attenuation is obtained.
The amplitude becomes infinite at one frequency. ζ = ∞ (c ₂ = ∞)
In the case of, the two weights move together, so that there is only one peak of resonance near the middle. If ζ is between these values, the two resonance amplitudes will be finite. What is desired of the system is that both peaks are equal and lower
ζ has an ideal value between 0 and ∞.

As shown in FIG. 12, there are points through which all the curves pass regardless of ζ, and they are called fixed points X and Y. If the heights of the fixed points are made equal (this is referred to as optimal tuning) and the condition that the amplitude curve becomes maximum near the fixed point is set (this is referred to as best attenuation), the dynamic vibration absorber is optimally designed. . The following equation can be obtained as the condition of the optimum tuning.

[0033]

(Equation 3)

At this time, the heights of the two points X and Y are equal. Also, the height of the two points X and Y is

[0035]

(Equation 4)

Is given by To increase the effect of the dynamic vibration absorber, the two resonance amplitudes must be as low as possible. The following equation is given as the condition of the best attenuation for that.

[0037]

(Equation 5)

As described above, the optimal design procedure of the dynamic vibration absorber 56 is as follows. (1) From Equation 10, μ is calculated by giving the ratio of the amplitude at the X and Y points to the static deflection, and the mass m ₂ of the dynamic vibration absorber is determined by Equation 5. (2) The natural frequency ω ₂ of the dynamic vibration absorber is calculated according to Expression 9, and the spring constant k ₂ is determined from Expression 8. (3) ζ is calculated by Expression 11, and the damping coefficient c ₂ of the dynamic vibration absorber is determined by Expression 4.

In the present invention, the T-shaped lever 12 supported by the bearings 25 and 26 is hung by a spring 47, and the weight 16 is attached to the support 14 which is a horizontal bar. In this way, the damping coefficient adjusting means 34 applies friction to the base end portion 13, thereby damping the vibration energy. According to such a configuration, the following advantages are achieved. By dividing removable weight, change of the added mass m ₂ is easily in the field, the installation position variable conversion equation spring, change the spring constant k ₂ is easily in the field, by a plurality of threaded plunger, attenuated easily change the coefficient c ₂ is in situ, the removable magnet, change the installation place easily in the field.

In FIG. 9 described above, the natural frequency ω ₂ of the horizontal spring supporting pendulum is expressed by Expression 12.

[0041]

(Equation 6)

A specific work procedure at the site will be described. (1) The weight m ₁ of the vibrating body 10 is roughly calculated from its volume and specific gravity. Example) m ₁ = 1000 kg (2) Determine how much the amplitude X ₁ of the vibrating body 10 at the time of resonance is desired to be suppressed. Example) The amplitude X ₁ at resonance, and 12 times the static deflection X _st of the vibrator. X ₁ / X _st = 12 (3) Calculate the mass ratio μ. Example) By substituting the amplitude ratio determined in the above (2) into Equation 10,

[0043]

(Equation 7)

(4) Weight m of the weight 16 of the dynamic vibration absorber 56
Calculate ₂ . That is, to stop the vibration of the vibrating body 10 having the mass m ₁ , the mass of the weight 16 may be m ₂ . Example) From equation 5, m ₂ = μm ₁ = 14 kg (5) Measure the vibration frequency ω ₁ of the vibrating body with an acceleration sensor or the like. Example: ω ₁ = 5 Hz (6) Calculate the natural frequency of the dynamic vibration absorber. Example) From equation (9),

[0045]

(Equation 8)

(7) Calculate the spring constant k ₂ of the dynamic vibration absorber. From Example) Formula _{8, k 2 = m 2 ω} 2 2 = 1367kgf / m (8) calculates the best attenuation zeta. Example) From equation 11,

[0047]

(Equation 9)

(9) Calculate the damping coefficient c ₂ of the dynamic vibration absorber. Example) From equation (4), c ₂ = 2ζm ₂ ω ₁ = 8.25 kgf · s / m (10) Originally, the weight m ₂ and the spring k ₂ are installed at the same position where r = L. In some cases, it is not possible to prepare a weight or spring whose value is exactly equal to m ₂ calculated in 4) or k ₂ calculated in (7). In that case, the installation positions of m ₂ and k ₂ are shifted in accordance with Expression 12. Example) When k ₂ = 1500 kgf / m, from equation 12,

[0049]

(Equation 10)

Then, a spring k ₂ and a weight m ₂ are installed at a position of r: L = 0.95: 1. (11) installed dynamic vibration absorber to the vicinity of the antinode of vibration of the vibrating body m _1. The operator looks at or touches the vibrating body 10 with his / her hand and finds a belly where the amplitude is large, that is, where the vibration is severe. (12) The damping coefficient adjusting means 34 is gradually activated and fixed at a position where the vibration of the vibrating body stops. That is, at first, the screw of the damping coefficient adjusting means 34 is loosened, and the screw is gradually tightened to strongly press the contact piece 36 against the contact surface 41 of the base end portion 13.

In the present embodiment, the mass m
_By calculating the ratio X ₁ / X _st of step 2 and the vibration frequency ω ₁ of step 4 in advance, the values at the other steps are calculated, for example, m ₂ , k ₂ ,
c ₂ , r / L can be easily obtained.

In another embodiment of the invention, m ₁ and the ratio X ₁
By preparing a table every time the values of / X _st and ω ₁ are different, m ₂ , k ₂ , c ₂ and r / L can be automatically calculated and obtained. That is, m ₁ , X ₁ / X by such input means, for example, a keyboard.
_{It is possible} to input _st and ω ₁ and automatically calculate and obtain m ₂ , k ₂ , c ₂ , and r / L by processing means using a microcomputer or the like. By viewing such values m ₂ , k ₂ , c ₂ , r / L, etc., the operator can perform the installation work of the present dynamic vibration absorber 56 with good workability on site.

The experimental results of the present inventor will be described. FIG.
Fig. 4 is a view showing the experimental results of the present inventor, showing the vibration state of the bent outer plate of the ship. FIG. 13A shows an experimental result when the dynamic vibration absorber 56 of the present invention is arranged on the belly caused by disturbance of the bent outer plate. As a result, it was confirmed that the vibration damping effect was sufficiently achieved, and even when forced vibration was applied, the vibration of the bent outer plate could be damped in about 10 seconds. On the other hand, when the dynamic vibration absorber 56 is not used, FIG.
3 (2), the vibration of the bent outer plate continues,
Vibration could not be suppressed. This confirmed that the dynamic vibration absorber of the present invention was sufficiently practicable.

[0054]

According to the first aspect of the present invention, the structure of the dynamic vibration absorber can be simplified, and a dynamic vibration absorber that is small, compact, and excellent in portability can be realized. Further, the installation and adjustment of the dynamic vibration absorber is easy, which is suitable for on-site use. Moreover, according to the dynamic vibration absorber of the present invention, there is provided a natural frequency omega ₁ unknown vibrator as an object, even if the scene there is a corresponding need, with easily set in the scene Can be installed. Further, according to the present invention, the dynamic vibration absorber can be realized at low cost.

Further, according to the present invention, since the base end of the lever has an arc shape, the damping coefficient of the dynamic vibration absorber by frictional contact can be stably achieved regardless of the angular displacement position of the lever.

According to the second aspect of the present invention, by adjusting the casing by screwing the casing to the dynamic vibration absorber main body, it is possible to easily adjust the damping coefficient due to the frictional contact.

According to the third aspect of the present invention, since the overall planar shape of the lever is formed in a T-shape, a relatively large damping coefficient can be achieved by using a plurality of damping coefficient adjusting means. Further, by using such a plurality of damping coefficient adjusting means, it is possible to prevent wear of a portion in frictional contact and extend the life.

According to the fourth aspect of the present invention, the mass m _{2 of the} weight, the spring constant k _2, and the mass m _{1 of the} vibrating body, the ratio X ₁ / X _st, and the vibration frequency ω _{1 of the} vibrating body are obtained. Since the positions where the weights and the springs are installed can be obtained by calculation or the like, it is easy to use on site and excellent in operability.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an overall configuration of a dynamic vibration absorber according to an embodiment of the present invention.

FIG. 2 is a side view of the dynamic vibration absorber.

FIG. 3 is a front view of the dynamic vibration absorber viewed from an end plate 4;

FIG. 4 is a front view of the weight 16;

FIG. 5 is a cross-sectional view taken along the line VV of FIG. 3;

FIG. 6 is a cross-sectional view showing a part of the attenuation coefficient adjusting means in a cutaway manner.

FIG. 7 is a front view of the attenuation coefficient adjusting unit shown in FIG. 6;

FIG. 8 is a diagram for explaining the principle of the dynamic vibration absorber of the present invention.

FIG. 9 is a simplified diagram of a dynamic vibration absorber 56.

FIG. 10 is a simplified cross-sectional view of a part of the vibrating body 10;

FIG. 11 is a graph showing experimental results of the present inventor.

[Figure 12] when changing the ζ damping ratio forced vibration frequency ratio ω / ω _1, showing the amplitude ratio of the main mass.

FIG. 13 is a view showing an experimental result of the inventor of the present invention, and shows a vibration state of a bent outer plate of a ship.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Dynamic vibration absorber main body 2 Bottom plate 3, 4 End plate 5, 6 Side plate 7, 8, 9 Permanent magnet piece 10 Vibration body 11 Ceiling plate 12 Lever 13 Base end part 14 Support body 15, 19, 20 Screw hole 16 Weight 16a, 16b Weight piece 17, 18 Play hole 21, 22 Hexagon socket head bolt 23, 24 Notch 25, 26 Bearing 27 Axis line 32 Target surface 34 Damping coefficient adjusting means 35 Casing 36 Contact piece 37, 47 Spring 40, 41 Contact surface 43 Bottom 56 Dynamic vibration absorber 57 Receiving jig 58 Surface plate

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hirohide Matsushima 1-1, Kawasaki-cho, Akashi-shi, Hyogo Kawasaki Heavy Industries, Ltd. Inside the Akashi factory (56) References JP-A-5-1746 (JP, A) JP-A JP-A-10-8765 (JP, A) JP-A-7-207986 (JP, A) JP-A-63-164639 (JP, U) JP-A-6-56536 (JP, U) (58) Fields investigated (Int) .Cl. ⁶ , DB name) F16F 15/02-15/08 E04H 9/02

Claims (4)

(57) [Claims] 1. A dynamic vibration absorber main body attached to a vibrating body, a lever, a base end provided on the dynamic vibration absorber main body so as to be angularly displaceable around a horizontal axis, and a rod-shaped member extending from the base end. A lever having a support, and a weight detachably mounted on the support of the lever at a weight mounting position along the longitudinal direction of the support, interposed between the dynamic vibration absorber main body and the support, A spring mounted at a spring mounting position along the longitudinal direction of the support, and a frictional contact with the base end of the lever on the side opposite to the support with respect to the horizontal axis, and the screw of the dynamic vibration absorber into the dynamic vibration absorber main body. A damping coefficient adjusting means provided so as to adjust the damping coefficient, wherein the base end of the lever has an arc-shaped contact surface centered on the horizontal axis, and the damping coefficient adjusting means is provided on the contact surface. Adjust the frictional contact pressure with the screw A dynamic vibration absorber characterized in that it is possible. 2. A damping coefficient adjusting means, comprising: a bottomed cylindrical casing having an external thread; an at least partially spherical contact piece partially exposed from an open end of the casing and in contact with the contact surface; A compression spring which is housed in the casing and is interposed between the bottom of the casing and the contact piece; and wherein an outer screw of the casing is screwed to an inner screw formed in the dynamic vibration absorber main body. The dynamic vibration absorber according to claim 1, wherein 3. The lever has a base end portion which is elongated in a direction perpendicular to the support, and the whole of the lever has a T-shape in plan view, and the damping coefficient adjusting means has an interval in the longitudinal direction of the base end. The dynamic vibration absorber according to claim 1 or 2, wherein a plurality of the vibration absorbers are arranged at intervals. 4. The dynamic vibration absorber according to claim 1, wherein a mass m ₁ of the vibrating body, an amplitude X ₁ of the vibrating body to be damped, and a static deflection X of the vibrating body are provided. _Using a predetermined ratio X ₁ / X _st to the _st and the vibration frequency ω ₁ of the vibrator, the mass m _{2 of} the weight, the spring constant k ₂ of the spring, and the weight in the longitudinal direction of the support of the lever Determine the installation position of the spring and the dynamic absorber in the vicinity of the antinode of the vibration of the vibrating body, and adjust the damping coefficient adjusting means so that the amplitude of the vibrating body is minimized. Vibration body damping method.