JPH01249435A - Composite damping body - Google Patents

Abstract

PURPOSE:To obtain damping body having superior variation controlling efficiency against vibrating motions of a wide temperature range and a wide frequency range, by respectively setting the glass transition temperature, loss factor and Young's modulus of a first and a second vibration controlling bodies to be provided with an objective body within a specific range. CONSTITUTION:A composite of vibration controlling bodies of this invention is formed by laminating a first and a second vibration controlling body layers 2, 3 on the surface of an objective body 1 to be vibration-controlled. When the respective glass transition temperature, internal loss factor at the glass transition temperature and Young's modulus at 20 deg.C of the first and second bodies 2 and 3 are represented by Tg1, Tg2, tandelta1, tandelta2, and E1, E2, they are so set as to hold (Tg1+10)<Tg2[ deg.C], 5E1<E2[Pa], and tandelta1>=0.5, tandelta2>=0.5. Two materials having the glass transition temperature different by 10 deg.C or more from each other are used for the first and second bodies 2, 3 which are coated over the body 1, so that a vibration controlling efficiency is effected in a wide temperature range. Moreover, the selected materials of the first and second bodies 2, 3 have the loss factor not less than 0.5, and therefore a high vibration controlling efficiency can be achieved. Since the first vibration controlling body 2 is covered with the second body 3 of a larger Young's modulus, a high vibration controlling efficiency against vibrations of a wide frequency range can be obtained.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention is a composite vibration damping system that is used in electronic equipment, audio equipment, precision equipment, etc. to reduce vibration and suppress secondary noise. Regarding the body.

(Prior art) Conventionally, electronic equipment, audio equipment, precision equipment, etc. have been subject to minute vibrations during manufacturing, or structural vibrations that occur when such equipment is mounted on ships, vehicles, aircraft, etc.・Noise etc. are prevented by attaching vibration damping bodies to the surface of the building structure to maintain product quality, prevent fatigue of the structure, and improve the environment in which equipment is used.

Such vibration dampers are made by attaching a viscoelastic material to the surface of a damped object such as a metal plate or plastic plate, and absorbing and attenuating vibration energy through its deformation, thereby suppressing the vibrations of the structure.
Those designed to reduce noise etc. are generally used. This type of damping body includes two types: one in which only a viscoelastic material is attached as a damping material to the damped body, and one in which a rigid plate-shaped restraining material is attached on top of the viscoelastic material layer. is known.

(Problem to be Solved by the Invention) However, in such conventional damping bodies, due to the inherent viscoelastic properties of the damping material used, the temperature range and vibration frequency range in which the damping effect is exerted are limited. There have been various problems, such as those with a limited range of vibration damping, or those with a wide effective range that do not have a very high vibration damping effect. For this reason, there has been a demand for the development of a vibration damping body that can provide higher vibration damping effects over a wider frequency range or a wider temperature range.

Various vibration damping bodies have been proposed in response to such demands. For example, Japanese Unexamined Patent Publication No. 82-110041 discloses a technique for eliminating these restrictions by forming a damper into a two-layer structure consisting of two types of glass transition temperatures having different moduli of elasticity. However, when considering application to recent precision instruments, it cannot be said that such a damping body has sufficient damping performance.

The present inventors conducted research to solve the above-mentioned problems regarding the type (non-constraint type) in which only a viscoelastic material is pasted as a damping material on the damped body. We have found that by selecting the glass transition temperature of the vibrating body, the internal loss coefficient at the glass transition temperature, and Young's modulus within appropriate ranges, high vibration damping performance can be exhibited over a wide frequency range and wide temperature range.

In general, in unrestrained damping bodies, the damping material mainly aims to attenuate bending vibrations, and its damping performance is
It is known that when the thickness of the damping material is constant, the larger the loss coefficient and the larger the Young's modulus, the better. It is also known that in polymeric materials, various physical properties such as loss coefficient and Young's modulus change rapidly along with thermodynamic properties such as volume and specific heat at the glass transition temperature of the material. There is.

The present invention skillfully applies the characteristics of such vibration damping materials to a composite vibration damping body, and when applied to precision equipment etc.
The purpose of the present invention is to provide an excellent composite vibration damping body that exhibits high vibration damping performance over a wide frequency range and a wide temperature range.

[Structure of the invention]

(Means for Solving the Problems) A composite damping body of the present invention is a composite damping body in which a first damping layer and a second damping layer are sequentially laminated on the surface of a damped body. In the body, the values of the glass transition temperature, internal loss coefficient at the glass transition temperature, and Young's modulus at 20°C of the first vibration damper are respectively Tgl, tan δ1, and El, and the glass transition temperature of the second vibration damper is , when the internal loss coefficient at the glass transition temperature and the value of Young's modulus at 20°C are E2, (Tg+ + 10)4g2 [°C]5E1 <
E2 [Pa] is characterized in that tan δ1 is 0.5 and tan δ2 is 0.5.

Examples of damping materials that can be used in the present invention include synthetic resins such as epoxy resins, butyl rubber, and rubber-like elastic bodies such as polynorbornene rubber.

The first vibration damping body and the second vibration damping body are generally appropriately selected from among many commercially available brands, and the means for forming them is not particularly limited. For example, a liquid damping body may be used. By applying the damping material, a sheet-like damping material may also be attached. Further, the first vibration damping body does not need to cover the entire surface of the vibration damped body, and may cover only a part of the body.

(Function) In the composite damping body of the present invention configured as described above,
First, two materials with glass transition temperatures different by 10°C or more are used.
By selecting them as the vibration allocating body and the second vibration damping body, combining them and coating the damped body, the vibration allocation performance can be exhibited over a wide temperature range. Also, loss coefficient (tanδ)
High vibration damping performance can be obtained by selecting materials for the first vibration damping body and the second vibration damping body, in which both are 0.5 or more. Then, a first damper is coated on the object to be damped, and a second material whose Young's modulus is sufficiently larger than the Young's modulus of the first damper is coated on the first damper. Since the damped body and the first damped body are coated as a vibration damping body, the damped body and the first vibration damped body become one and behave as a new damped body. The damping performance of the vibration damping body against bending vibrations is similar to the case where the second damping body is used alone, and high vibration damping performance against vibrations of a wide range of frequencies can be obtained.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram schematically showing a cross section of an embodiment of the present invention. As shown in the figure, this embodiment has a structure in which a first vibration damping body 2 is attached to the surface of a vibration-damped body 1]7, and a second vibration damping body 3 is further attached thereon. ing. Note that the first vibration damper 2 and the second vibration damper 3 are made of a material that satisfies the conditions of the present invention described above. In order to investigate the effect of the present invention regarding this example, a composite vibration damper was manufactured by changing the type and thickness of the first vibration damper 2 and the second vibration damper 3, and its damping performance was evaluated as follows. 1lpj was determined. Furthermore, as a comparative example, the damping performance was similarly evaluated as A for a damping body equipped with a conventional single-layer damping material and a damping body that did not meet the conditions of the present invention with a two-layer damping material attached.
l1 was determined.

FIG. 2 shows the vibration damping test results of this example. Second
As is clear from the figures and tables, the composite vibration damper of this example exhibits high vibration damping performance against vibrations in a wide frequency range.

(Left below) However, 0. Attenuation coefficient (C/Ce) 0.4% or more Δ
Less than 2-4%
Figure 3 is a cross-sectional view of another embodiment of the present invention.

This composite vibration damper is made by pasting a sheet-like first vibration damper 2 on the surface of a damped body 1 serving as a base material, and then applying a liquid second vibration damper 3 and hardening it. This is what was obtained. When the damping performance of this composite damping body was determined by al,
It was confirmed that it exhibited a vibration damping effect equivalent to that of the structure shown in Figure 1.

[Effects of the Invention] As explained above, according to the present invention, the glass transition temperature, loss coefficient, and Young's modulus of the first vibration damper formed in the composite vibration damper and the first vibration damper can be adjusted. Since the range is set, it is possible to provide a vibration damping body having excellent vibration damping performance against vibrations in a wide temperature range and a wide frequency range.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of one embodiment of the present invention, Fig. 2 is a graph showing vibration damping test results for vibration damping bodies of this embodiment and a comparative example, and Fig. 3 is a cross-sectional view of another embodiment of the present invention. It is a diagram. 1...Body to be damped 2...First damping body 3...Second vibration damping body

Claims (1)

[Claims] (1) In a composite damper formed by sequentially laminating a first damper layer and a second damper layer on the surface of a damped body, the glass transition temperature of the first damper , the internal loss coefficient at the glass transition temperature and the Young's modulus at 20°C,
When Tg_1, tanδ_1, and E_1 are respectively, and the glass transition temperature of the second vibration damper, the internal loss coefficient at the glass transition temperature, and the Young's modulus at 20°C are E_2, (Tg_1+10)<Tg_2[°C] 5E_1< E_2 [Pa] A composite damping body characterized in that tan δ_1≧0.5 and tan δ_2≧0.5.