JPH06193678A - Dynamic vibration absorber - Google Patents

Abstract

PURPOSE:To improve the following disadvantages inherent in the conventional dynamic vibration absorber that 1) in order to accord with natural frequency accurately, lots of small weight must be adjusted aright, therefore it is troublesome indeed, 2) reliability as an apparatus is inevitably lowered and 3) since heaviness of a weight and the center of gravity are varied according to the addition and subtraction of the small weight, an adverse effect is exerted on even in the performance of a dynamic vibration absorber. CONSTITUTION:This dynamic vibration absorber is provided with a weight 2 whose lower end is supported on a damping objective structure as being free of slide motion in the horizontal direction via two sliders 6 and 6, an upper spring supporting member 9, shiftable in the vertical direction, projectingly installed at both ends of the weight 2 in the horizontal direction, a lower spring supporting member 8 whose upper ends are opposed at a proper interval in a spot just under the upper spring supporting member 9 while the lower end is erected on the damping objective structure, and each of nonlinear characteristic springs 7, whose rigidity in the horizontal direction varies according to a variation in vertical length, inserted into an interval between both these spring supporting members.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dynamic vibration absorbing device for suppressing horizontal vibration.

[0002]

2. Description of the Related Art As shown in FIG. 6, a conventional dynamic vibration reducer 01 comprises a weight 02 and a spring 03, and a structure to be damped 0
It is attached to 4. Then, by matching the natural frequency Ω ₀ of the vibration suppression target structure 04 with the natural frequency Ω of the dynamic vibration absorber 01, the vibration of the vibration suppression target structure 04 is reduced. Here, the natural frequency Ω is given by the equation (1) by the mass M of the weight and the rigidity K of the spring 03. Ω = √ (K / M) Therefore, in order to adjust Ω ₀ , it suffices to change the mass M or the rigidity K, but generally, a means for changing M is adopted, and for that purpose, the weight A large number of small weights 05 are stacked as a part of 02, and the small weight 05 is adjusted to adjust the mass M of the weight 02.

[0003]

However, in this type of dynamic vibration reducer, the natural frequency Ω of the dynamic vibration reducer 01 can be varied over a wide range, and the natural frequency Ω ₀ of the target structure can be accurately matched. In order to do so, it is necessary to adjust a large number of small weights 05, which makes the adjustment difficult and reduces the reliability of the device. Moreover, since the weight and the center of gravity of the weight 02 change as the small weight 05 is adjusted, the performance of the dynamic vibration reducer 01 is also adversely affected.

The present invention has been proposed in view of the above circumstances, and an object thereof is to provide a high-performance dynamic vibration absorbing device which is easy to adjust and has high reliability.

[0005]

Therefore, according to the invention of claim 1, a lower end of a weight having a lower end slidably supported on a structure to be damped in a horizontal direction via a slider, and the above-mentioned weight. Vertically movable upper spring support members respectively attached to both ends in the horizontal direction, and upper ends of the upper spring support members face each other at appropriate intervals directly below the upper spring support members, and the lower ends thereof are the structures to be damped. A lower spring support member standing upright,
And a non-linear spring which is inserted between the spring support members and whose rigidity in the horizontal direction changes according to the change in the length in the vertical direction.

According to a second aspect of the present invention, in the first aspect of the present invention, horizontal vibration of the structure to be damped is detected, and based on this, the upper spring support member is automatically moved in the vertical direction. According to the present invention, means for controlling the rigidity of the non-linear spring is provided.

The invention of claim 3 relates to claim 1 or claim 2.
In the invention, the relative distance between the both spring supporting members is made variable in the horizontal direction instead of the vertical direction, and the nonlinear characteristic in the vibration direction of the inserted nonlinear spring is used.

[0008]

According to the structure of claim 1, in the dynamic vibration absorber, the rigidity K can be adjusted by adjusting the height of the spring, so that the dynamic vibration absorber is not required to increase or decrease its weight. The frequency can be easily set to the required value.

According to the second aspect of the invention, the vibration of the structure to be damped is automatically detected, and the height of the spring is automatically controlled based on the vibration, whereby a semi-active dynamic vibration absorber. Is obtained.

Further, according to the third aspect of the invention, the invention of the first or second aspect can be implemented by utilizing the non-linear spring having various characteristics.

[0011]

1 is a front view showing a first embodiment of the present invention, FIG. 2 is a characteristic view of the non-linear spring shown in FIG. 1, and FIG. 3 is a second view of the present invention. 4 is an enlarged view showing a non-linear spring of FIG. 3 and a side view thereof, and FIG. 5 is an enlarged view showing a V portion of FIG.

First, in the first embodiment shown in FIGS. 1 and 2, the upright cube-shaped weight 2 is supported on the vibration-damping target structure 4 via linear actuators (sliders) 6 and 6. , Weight 2
Steel plates 9 are horizontally projected on the left and right sides of the
Set up. The left and right T-shaped steels 8 and 8 erected on the vibration-damped structure 4 are used for the spring receiver of the non-linear spring (hereinafter referred to as a spring) 7, and the steel plate 9 is moved up and down by the lifting device 10. There is.

In such a device, if the mass of the weight 2 is M and the rigidity of the spring 7 is K, the natural frequency of this dynamic vibration absorber can be obtained by the equation (1). Ω = √ (K / M) ………………………… (1) Here, the stiffness K of this spring 7 is a function of the static deflection x of the nonlinear spring, as shown in FIG. Usually, as shown in the figure, the relationship between the rigidity K and the static deflection x is expressed by the equation (2). ^{Kα (1 / x r) (} r> 1) ...... (2) Therefore, by lowering the height of the spring 7 by the upper and lower unit 10 (see FIG. 3), it is possible to adjust the rigidity K . Therefore, the dynamic vibration absorbing device according to the present invention can set its natural frequency to a required value by adjusting the height of the spring.

Such a dynamic vibration reducer 1a does not use a large number of small weights, but uses a non-linear spring whose rigidity changes depending on the static deflection of the spring. Can be adjusted. Therefore, the performance and reliability of the dynamic vibration reducer can be improved.

Next, a second embodiment in which the present invention is applied to damping the upper structure of a ship will be described with reference to FIGS.
Fig. 3 is the entire front view, and Figs. 4 and 5 are IV of Fig. 3, respectively.
FIG. 5 is an enlarged view showing a portion and a V portion.

In the above drawing, the same reference numerals as those in FIGS. 1 and 2 indicate the same members as those in the drawings, and the difference of the second embodiment from the first embodiment is that of the first embodiment. The structure is equipped with a semi-active control mechanism to control the spring rigidity.

That is, in FIGS. 3 to 5, the weight 2 is placed on the slider 6, the steel plates 9 are attached to the left and right of the weight 2, and the non-linear spring 7 is installed. Further, T-shaped steel is used for the spring bearing of the nonlinear spring 7. As shown in FIG. 5, the steel sheet 9 has a structure that is movable only in the vertical direction by a ball bearing 21 and a pair of upper and lower auxiliary springs 11.
It is performed by combining with 3.

In this embodiment, the number of revolutions of the propeller shaft 19 is detected by the detector 18, and the signal is sent to the calculator 16 via the amplifier 17. On the other hand, the detector 22 attached to the weight 2 sends an operation signal (speed, displacement, acceleration, etc.) of the weight 2 to the amplifier 17, and the amplified signal is used as the calculator 16
Is sent to and is compared with the signal of the propeller speed and calculated. For the calculation, for example, a calculation such as “output a signal that matches the frequency of the N-fold component of the propeller shaft rotation speed” is performed. The resulting signal is sent to the output amplifier 15 and drives the motor 14 to move the steel plate 9 up and down.

In such a device, assuming that the mass of the weight 2 is M and the rigidity of the nonlinear spring 7 is K, the natural frequency of this dynamic vibration absorbing device can be obtained by the equation (1). Here, the rigidity K of the non-linear spring 7 is as shown in FIG.
It is a function of the amplification x and the static deflection and is shown by equation (2).

In the second embodiment, since the frequency of the structure to be damped is calculated from the N-fold component of the rotation speed detected from the propeller shaft, the motor is always operated according to the fluctuation of the rotation speed of the propeller shaft. By increasing and decreasing the height of the spring 7 so that the dynamic vibration absorbing device 1b is most effective by 14, the natural frequency of the device can be automatically set to a required value.

According to the second embodiment, a non-linear spring whose rigidity changes depending on the static deflection of the spring is used without using a large number of small weights. Natural frequency can be adjusted. Therefore, labor and labor can be saved, and the performance and reliability of the dynamic vibration reducer can be improved.

In both the first and second embodiments, the non-linear spring is an example in which it is supported at both ends in the vertical direction and exhibits the non-linear characteristic in the horizontal direction. However, depending on the type of the non-linear spring,
Since there are those supported at the left and right ends and vibrating in the same direction or the front-back direction to exhibit non-linear characteristics, there are those supported at the front and rear ends and vibrating in the same direction or the left-right direction to exert non-linear characteristics, etc. Also in these cases, by selecting the relative movement directions of the pair of spring support members as the corresponding directions, it is possible to utilize the non-linear springs having various structures and characteristics.

[0023]

In summary, according to the invention of claim 1, the lower end of the weight whose lower end is slidably supported on the structure to be damped in the horizontal direction via the slider, and the horizontal direction of the weight. The upper spring support members, which are respectively attached to both ends and are movable in the vertical direction, and the upper ends of the upper spring support members face each other with an appropriate gap immediately below the upper spring support members, and the lower ends thereof stand on the vibration suppression target structure. The lower spring support member provided and the non-linear spring that is inserted between both spring support members and whose rigidity changes in the horizontal direction according to the change in the length in the vertical direction are easy to adjust. INDUSTRIAL APPLICABILITY The present invention is extremely useful industrially because a dynamic vibration absorbing device with high reliability and high performance is obtained.

According to the invention of claim 2, claim 1
In the invention described above, means for controlling the rigidity of the non-linear spring by detecting horizontal vibration of the structure to be damped and automatically moving the upper spring support member in the vertical direction based on the detected vibration. In addition to the effect according to claim 1, the present invention provides a semi-active dynamic vibration absorbing device that automatically controls the frequency, so that the present invention is extremely useful industrially.

Further, according to the invention of claim 3, the invention of claim 1 or claim 2 can be implemented by utilizing the non-linear springs having various structures and characteristics, so that the present invention is extremely useful industrially. It is something.

[Brief description of drawings]

FIG. 1 is a front view showing a first embodiment of the present invention.

FIG. 2 is a characteristic diagram of the non-linear spring of FIG.

FIG. 3 is a front view showing a second embodiment of the present invention.

FIG. 4 is an enlarged view showing a portion IV in FIG.

5 is an enlarged view showing a V portion of FIG.

FIG. 6 is a front view showing a conventional dynamic vibration reducer.

[Explanation of symbols]

 1a, 1b Dynamic vibration absorber 2 Weight 3 Non-linear spring (spring) 4 Structure to be damped 5 Small weight 6 Linear actuator (slider) 7 Non-linear spring 8 T-shaped steel 9 Steel plate 10 Vertical device 11 Screw rod 12 Wire 13 pulley 14 motor 15 amplifier 16 calculator 17 amplifier 18 detector 19 propeller shaft 20 propeller 21 ball bearing 22 vibration detector

Claims (3)

[Claims] 1. A weight having a bottom end slidably supported in a horizontal direction on a structure to be damped through a slider, and vertically movable attached to both horizontal ends of the weight. Of the upper spring support member, the lower spring support member having the lower end erected on the vibration suppression target structure, the upper end facing each other immediately below the upper spring support members at appropriate intervals and the lower end, A dynamic vibration absorbing device, comprising: a non-linear spring that is inserted between spring support members and has a horizontal rigidity that changes in accordance with a change in vertical length. 2. The non-linear type according to claim 1, wherein horizontal vibration of the structure to be damped is detected and the upper spring supporting member is automatically moved in the vertical direction based on the detected vibration. A dynamic vibration damping device comprising means for controlling the rigidity of a spring. 3. In the invention of claim 1 or 2,
A dynamic vibration absorbing device, characterized in that the relative distance between the two spring supporting members is made variable in the horizontal direction instead of the vertical direction, and the nonlinear characteristic in the vibration direction of the inserted nonlinear spring is utilized.