JPH02304231A - Kinetic viscosity absorber - Google Patents

Abstract

PURPOSE:To enable the damping of a vibration with a single absorber in each vibration mode of a plurality of resonance frequencies of a machine construction body by applying the constitution wherein a material having mass displacing as a rigid body during a vibration and another material having viscosity and elasticity for supporting the aforesaid material are so mounted so to have different elasticity and viscosity depending upon the direction of the vibration. CONSTITUTION:The weight of mass 2 is changed via the replacement thereof with a metal material having different specific gravity so that when a machine construction body is generating a bending vibration at a resonance frequency of Fx in the X-axis direction of rectangular coordinates set for the body, due to its own vibromotive force or an external vibration, a resonance frequency fx acting in the X-axis direction of a kinetic viscosity absorber will resonance with the frequency of Fx. Also, the volume of the mass 2 is changed to increase or reduce the weight thereof. Or the hardness of a visco-elastic material 3 such as butyl rubber is changed, or the thickness, area or the like thereof is changed to alter viscosity, thereby enabling the damping of the vibration of the machine construction body. Furthermore, for the bending vibration of the machine construction body at a resonance frequency of FY in the Y-axis, the mass 2 and the material 3 are rectangular parallelopiped to be anisotropic and a resonance frequency fr acting in the Y-axis is made to agree to the FY, thereby obtaining a vibration damping effect.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a kinematic viscous vibration absorber attached to a mechanical structure. [Summary of the invention]

The present invention provides a kinematic viscous vibration absorber that is attached to a mechanical structure and is made of a mass and a viscoelastic material, which includes a material that has mass that is displaced as a rigid body during vibration, and a material that has viscosity and elasticity that supports the material that has that mass. By adopting a mounting structure that has different elasticity and viscosity depending on the direction of vibration, it is possible to respond to vibration modes that occur at multiple frequencies in mechanical structures by having a resonance frequency that matches each vibration mode. This is a dynamic viscous vibration absorber that reduces vibrations caused by multiple resonances. [Prior Art] Conventionally, as shown in FIG. 3, the mass m, which is attached to a mechanical structure, is
A method in which a kinematic viscous vibration absorber with fixed spring constant k and damping constant C is installed, or a method in which multiple kinematic viscous vibration absorbers are used in accordance with multiple resonance frequencies and vibration modes as shown in Figure 4. was known.

[Problem to be solved by the invention]

However, conventional kinematic viscous vibration absorbers have the effect of reducing vibration amplitude only for vibration modes at a specific resonance frequency, and in mechanical structures that vibrate in multiple vibration modes, multiple vibration dampers corresponding to each There is a problem in that it is necessary to attach a viscous vibration absorber, and furthermore, it is necessary to prepare in advance a place in the mechanism structure for attaching a plurality of dynamic viscous vibration absorbers. Therefore, in order to solve these conventional problems, the present invention aims to provide a dynamic viscous vibration absorber that uses only one or at least fewer vibration modes than the number of vibration modes, even when a mechanical structure vibrates in vibration modes at multiple resonance frequencies. The purpose is to reduce vibration amplitude at multiple resonant frequencies. [Means for Solving the Problems] The kinematic viscous vibration absorber of the present invention is a kinematic viscous vibration absorber made of a mass and a viscoelastic material, which is attached to a mechanical structure. Supports materials that have mass. It is characterized by a mounting structure in which a material having viscosity and elasticity has different elasticity and viscosity depending on the direction of vibration. [Function] According to the kinematic viscous vibration absorber of the present invention configured as described above, when a mechanical structure vibrates in each vibration mode at a plurality of resonance frequencies, it vibrates in a vibration mode at the corresponding frequency. By using a kinematic viscous vibration absorber in which the shape of the mass, the shape of the viscoelastic material, and the mounting position are adjusted so as to reduce the amplitude, it is possible to reduce the vibration amplitude at multiple resonance frequencies with a single dynamic viscosity vibration absorber. [Examples] Examples of the present invention will be described below based on the drawings. In Figure 1, a mechanical structure l has one end fixed on a horizontal plane, and a rectangular parallelepiped-shaped mass 2 made of a relatively hard-to-deform and high-density material (e.g. metal, ceramic, etc.) at the other end, which has viscosity and elasticity at the same time. The kinematic viscous vibration absorber is formed by the mass 2 and the viscoelastic material 3.The arrows fx and fy shown in the figure indicate the direction of vibration. , the frequency is also written nearby. In the embodiments described above, the mechanical structure generates bending vibration at the resonant frequency Fx in the X-axis direction of the orthogonal coordinate system set for the mechanical structure due to its own excitation force or vibration from the outside. In this case, the weight of the mass 2 is changed by replacing it with a metal material having a different specific gravity, or by changing the volume, so that the resonance frequency fX that effectively works in the X-axis direction of the kinematic viscous vibration absorber vibrates in accordance with Fx, and By changing the hardness, thickness, area, etc. of the viscoelastic material 3 such as butyl rubber, elasticity and viscosity can be changed and vibration of the mechanical structure can be reduced. In addition, the mass 2 and the viscoelastic material 3 of the kinematic viscous vibration absorber are made into a rectangular parallelepiped shape to have anisotropy and act in the Y-axis direction against bending vibration at the resonance frequency FY in the Y-axis direction of the mechanical structure. (A vibration reduction effect can be obtained by matching the resonant frequency fy to FY.) Figure 2 shows another embodiment that utilizes different vibration modes of the dynamic viscosity absorber, in which a thin cylindrical mass 2 is It is fixed to the mechanical structure l via a disc-shaped viscoelastic material 3. In this embodiment, as in the embodiment of FIG. Both Viscoelastic Material 2 and Viscoelastic Material 3 do not have any anisotropy in shape or properties, so the resonance frequency fx and vibration mode of the effective vibration reduction effect are the same. When l generates torsional vibration, the mass 2 and the viscoelastic material 3 are adjusted so that the resonant frequency fθ that effectively acts against the torsional vibration of the kinematic viscous vibration absorber matches the resonant frequency FO of the torsional vibration of the mechanical structure.
By adjusting the mass and viscoelastic properties of the torsional vibration, the effect of reducing torsional vibration can be obtained. Figure 3 shows an example in which the kinematic viscosity vibration absorber shown in Figure 2 is applied to a horizontal multi-joint robot. It is attached on the axis of the rotating main shaft 4 inside the first rotating arm 5 of the horizontal articulated robot 1 via the material 3 . As shown in FIG. 2, this embodiment provides a vibration reduction effect when the horizontal articulated robot generates torsional vibration around the main shaft 4 for one revolution and when bending vibration occurs in the horizontal plane. be able to. [Effects of the Invention 1] As described above, according to the present invention, a material with a mass that is displaced as a rigid body during vibration, and a material with viscosity and elasticity that supports the material with that mass are made to have elasticity and elasticity depending on the vibration direction. By using a mounting structure with different viscosity, it has multiple vibration modes and resonance frequencies that differ depending on the vibration direction, and by matching these to the respective resonance frequencies of the mechanical structure, each of the multiple resonance frequencies of the mechanical structure can be adjusted. For each vibration mode, simply installing one kinematic viscosity vibration absorber has the effect of reducing the vibration amplitude of each vibration mode.

[Brief explanation of drawings]

FIGS. 1, 2, and 3 are schematic diagrams showing an embodiment of a dynamic viscosity vibration absorber according to the present invention, and FIGS. 4 and 5 are schematic diagrams of a conventional dynamic viscosity vibration absorber. l...Mechanical structure 2...Material 3...Viscoelastic material 4...Rotating spindle 5...First rotating arm and above Applicant Seiko Epson Corporation Agent Patent attorney Kizobe Suzuki ( 1 other person) Sen4zu

Claims (1)

[Claims] A dynamic viscous vibration absorber made of a mass and a viscoelastic material, which is attached to a mechanical structure, includes a material with mass that is displaced as a rigid body during vibration, and a material with viscosity and elasticity that supports the mass. A kinematic viscosity vibration absorber characterized by having a mounting structure in which the material has different elasticity and viscosity depending on its vibration direction.