JPH0287428A - Insulator - Google Patents

Abstract

PURPOSE:To absorb and consume the vibration energy in the vent of earthquake by a dynamic vibration absorber and decrease vibration of an electric apparatus to a great degree by filling a hollow in an insulator body with a viscous fluid, and installing a cantilever having a weight at its tip with possibility of vibrating in this viscous fluid. CONSTITUTION:An insulator 10 is provided with a screw hole 11b, whose top a coupling screw is driven in, and a groove 11c for insertion of an O-ring, and composed of insulator body 11 with a hollow 11d alongside the center line, a viscous fluid 12 filling this hollow 11d and having a certain viscosity, a through hole 13a for a coupling screw installed at the top of the insulator body 11, and a lid 13 provided with a seated hole 13b, and a cantilever 15, whose top is fixed a lid 13 and which extends to the center of the hollow 11d and is fitted at the bottom with a weight 14 having a specified mass. The vibratory energy at a certain frequency is absorbed and consumed by setting the natural frequency and damping factor of the vibration system composed of cantilever 15 and weight 14 to certain values, and thus the response of an electric appliance at this frequency can be decreased to a great degree.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to an insulator used in earthquake-resistant structures of electrical equipment and the like.

(Prior Art) FIG. 2 shows an example of an electrical device using a conventional insulator. In the figure, reference numeral 1 denotes an electrical device, and electrical components 48 to 4e are fixed between an upper support member 2 and a lower support member 3. When it is necessary to electrically insulate the upper support member 2 and the lower support member 3, insulators are used to connect them. , 58-5f.

Figure 3 shows a cross section of this paddle 5.

Flange portions 5a and 5b are provided at both ends, and a 60 is provided at each of the flanges 5a and 5b to connect with the upper support member 2 and the lower support member 3, and to connect the paddles 5 to each other. It is provided. Further, a hollow portion 5c is provided along the center line.

(Problems to be Solved by the Invention) By the way, when the electrical equipment 1 as described above is subjected to external vibrations such as an earthquake, each component such as the electrical components 4a to 4e and the insulators 5a to 5f may be permanently deformed. It is required that no damage occurs, and that it is necessary to quickly return to the original normal state after the earthquake. In order to satisfy these demands, it is necessary to improve the reliability of each part of the electric machine H:+1 during an earthquake, as well as to improve the reliability of the electrical components 4a to 4e and gauges 5a to 5f that are housed. need to be reduced.

Therefore, let us consider a method of reducing the response of the electrical equipment 1 when an earthquake occurs. The frequency component included in an earthquake is thought to be 0.5 to 101 Hi based on the ml Kl'l data up to now, and if the natural frequency of the electrical equipment 1 is within this range,
During an earthquake, resonance occurs and the response becomes larger.

Therefore, one possible measure to reduce the response during an earthquake is to set the natural frequency of the electrical equipment 1 outside the frequency range included in earthquakes, that is, 0.57 or less or 1011z or more.

Generally, when a structure is approximated by a one-degree-of-freedom system, its natural frequency is expressed by the following equation.

However, fn: Natural frequency K = Rigidity of the structure m: Mass of the structure In order to make the natural frequency of the electrical equipment 1 very small, 0.57 or less, its stiffness K is determined from equation (1). Make it smaller or better! It is conceivable to make # and m very large.

One possible way to reduce the rigidity K is to support the electrical equipment 1 with something like soft rubber, but not only do you have to secure space to install them, but you also have to worry about the long-term reliability of the rubber. Another problem arises: securing the moreover.

In reality, supporting with rubber alone is not sufficient, and a damper or the like must be installed in order to provide damping to the support system, resulting in a significant cost.

In addition, increasing the mass m will not only add a large amount of unnecessary mass, which is not desirable for the product, but also significantly increase the strength of each component so that it can statically withstand the increased mass. In reality, this is difficult.

On the other hand, in order to make the natural frequency of the electrical equipment 1 greater than or equal to IO+Iz, the stiffness K is increased based on the above equation (1).

Alternatively, consider reducing the quality ff1m.

In order to increase the rigidity K, it is conceivable to increase the number of joints between the upper support member 2 and the lower support member 3 by the paddle 5, but this may make it impossible to secure storage space for the electrical components 48 to 4e, or the electrical equipment 1 Not only does the overall size of the paddle 5 increase, but also the cost increases due to the increase in the number of paddles 5.

Additionally, if the dimensions and number of shields 5 are changed, design changes such as the mounting position and arrangement of electrical components #+4a to 4e to be stored will affect the entire electrical equipment 1, resulting in the cost and time required for redesign. will increase significantly.

It is actually impossible to reduce the quality of the electrical equipment 1 by 1 m. That is, it is not possible to reduce only the mass while maintaining the current strength, and it is not possible to expect a significant weight reduction of the electrical components 48 to 4e to be housed.

As described above, when the natural frequency of the electrical equipment 1 is within the frequency range included in earthquakes (0.5 to 1oITz), the method of reducing the response during an earthquake by changing the natural frequency is as follows: This had the disadvantage of causing a significant increase in varnish 1 and a significant design change of the electrical equipment 1. Therefore, an object of the present invention is to eliminate the need to change the design of other stored items without causing an increase in cost. The object of the present invention is to provide an insulator that can reduce the response to external vibrations such as earthquakes.

[Structure of the invention]

(Means for Solving the Problems) The present invention fills a hollow part provided in an insulator body with a viscous fluid, provides a cantilever beam with a weight at the tip so as to be able to vibrate inside the viscous fluid, and is controlled by these. This is a dynamic vibration absorber with a vibration function.

(Function) When an external force such as an earthquake acts on a device to be damped, the weight vibrates inside the viscous fluid, consuming the vibration energy applied from the external vibration and reducing the vibration of each part of the device to be damped. let

(Embodiment) An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a sectional view of an insulator according to an embodiment of the present invention.

In the same figure, the insulator 1O has a flange 11a at the lower end, and a screw hole 11 into which the coupling screw is screwed into the upper end surface.
b and a groove 11c for inserting an O-ring, and a hollow part 11d along the center line.
d (leaving a slight gap at the top) and a viscous fluid 12 having a predetermined viscosity;
It is composed of a lid 13 having a counterbore 13b and a cantilever beam 15 fixed to M13 at its upper end, extending to the center of the hollow lid, and having a weight 14 having a predetermined mass at its lower end.

In addition, the insulator body 11 has a ○ ring 16 in the groove 11c.
is inserted, and the lid 13 is attached with a connecting bolt 17 to prevent the viscous fluid 12 filled in the hollow lid from leaking. In addition, the flange lla and the lid 13 may be connected to an upper support member or a lower end support member (not shown), or may be connected to the cover 10.
1 with a hole through the bolt for interconnecting the
3c are provided respectively.

Next, the operation of the insulator 10 configured as above will be explained. First, the viscous fluid 12° cantilever beam 152 and weight 14 of the insulator 10 act as a dynamic vibration absorber.

That is, one cantilever beam15. By setting the natural frequency and damping rate of the vibration system constituted by the weight 14 to predetermined values, vibration energy at a certain frequency is absorbed and consumed, and the response of the 41-ki equipment 1 at that frequency is significantly reduced. This is a well-known physical development process.

Now, consider an earthquake as an example of an external force acting on the electrical equipment 1. When the natural frequency of the electrical equipment 1 is within the frequency range included in an earthquake, the response vibration of the electrical equipment 1 during an earthquake includes the viscous fluid 12 of the six insulators 10 whose natural vibration component is predominant.
．． The specifications are determined so that the frequency at which energy is absorbed and consumed by the dynamic vibration absorber composed of the cantilever beam 159 and the weight 14 becomes the natural frequency of the electrical equipment 1. In this way, most of the vibration energy applied to the electrical equipment 1 due to an earthquake can be absorbed and consumed by the dynamic vibration absorber, and the vibrations of each part of the electrical equipment 1 can be significantly reduced.

Here, the specifications of the dynamic vibration absorber can be determined as follows using the theory of optimal adjustment of dynamic vibration absorbers. That is,
The natural frequency of electrical equipment 1 is Ω. Mass of binding and weight 14 m
The natural frequency Wn of the dynamic vibration absorber is expressed by a linear equation, where μ is the ratio of the equivalent mass of

The weight 1 is set so that the natural frequency of the dynamic vibration absorber becomes Wn'.
Since it is easy to determine the mass of 4 and the rigidity of cantilever 15, this explanation will be omitted.

Furthermore, the optimum damping rate ζ of the dynamic vibration reducer is determined by the following equation.

here.

ζ=C/2I, lΩ.・・・・・・
...(A) However, C: Damping constant The damping constant C having the optimum damping rate ζ can be easily obtained using the equation (2), and the viscosity of the viscous fluid 12 can be determined.

Note that the embodiment described above has a weight 14 at the tip (lower end).
A cantilever beam 15 having
A similar effect can be obtained by attaching it to the bottom surface of d so as to protrude upward.

In addition, two sets of cantilever beams 15 having weights 14 at the tips are prepared by combining them, one set is attached to the lower surface of the lid 13 so as to protrude downward, and the other set is attached to the hollow part of the insulator body 11. A similar effect can be obtained by attaching it to the bottom surface of 11d so as to protrude upward.

In addition, although the object that absorbs and consumes vibrational energy has been described as an earthquake, the object of the present invention is not limited to earthquakes alone; for example, external vibrations from rotating equipment installed in the vicinity are transmitted, Even if device 1 vibrates,
If the specifications of the dynamic vibration reducer are adjusted so as to absorb and consume the transmitted external vibration energy, the resulting response vibration of the electrical equipment 1 can be significantly reduced.

〔Effect of the invention〕

As explained above, according to the present invention, vibration energy during an earthquake is absorbed and consumed by a dynamic vibration absorber composed of nine cantilevers of viscous fluid inside an insulator and a weight, thereby significantly reducing vibrations of electrical equipment. Therefore, it is possible to provide an insulator that can reduce costs and improve reliability by reducing the weight of the electrical equipment 1.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of the present invention, FIG. 2 is a front view showing an example of an electric device using a conventional insulator as a structural member, and FIG. 3 is a cross-sectional view showing a conventional insulator. 11...Insulator body, lid...Hollow part 1
2... Viscous fluid, 14... Weight 15...
・Cantilever agent Patent attorney Nori Ken Yudo Chika Ken Daishimaru■ Figure 1e

Claims (1)

[Claims] A hollow part provided in the insulator body is filled with viscous fluid, and a cantilever beam with a weight at the tip is provided to vibrate inside the viscous fluid, and these constitute a dynamic vibration absorber having a vibration damping function. It's tough.