JPH0433472Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] This invention relates to a piping vibration damper interposed between a structure and piping. It is characterized by being attenuated by. The term "vibration suppressor" referred to here refers to a device that does not restrain the slow displacement of piping caused by thermal changes, but can restrain sudden vibrations caused by earthquakes, etc.

[Conventional technology]

A control system that converts linear displacement or vibration caused in piping to a structure into rotational motion of a rotating shaft, and dampens the vibration by the inertial resistance of a cylindrical weight attached to this rotating shaft. Shakers are known. (For example, Special Publication No. 50-39236).

[Problems that this invention attempts to solve]

In general, when a vibration suppressor is loaded with vibration at a frequency that causes resonance, it requires an abnormally large resistance in order to suppress the vibration. However, as described above, the known dampers rely only on inertial resistance for their damping action. As a result, in order to withstand the excessive loads in this resonant frequency band, the damper must have an unusually strong overall design, which necessarily increases the size of the structure. Therefore, a problem arises in that installation is restricted to a narrow space. In recent years, efforts have been made to reduce construction costs, and efforts have been made to efficiently downsize buildings at nuclear power plants and the like. As a result, the installation space for piping systems is narrow, and miniaturization of related equipment has become the ultimate challenge.

[Means for solving problems]

This problem cannot be solved by relying only on the inertial resistance of the weight that rotates back and forth.

In this invention, a cylindrical weight is equipped with multiple rocking bodies, and when the resonance frequency band is reached, each rocking body senses the angular acceleration at that time, collides with the outer wall using centrifugal force, and the energy loss due to the collision causes resonance. Since the structure is such that the excessive load on the device is reduced, it is possible to downsize the device.

〔Example〕

The main case 1 has a cylindrical shape and includes a handle 1a at one end. The sub case 2 also has a cylindrical shape and is inserted into the main case opposite to each other, and is provided with a handle 2a at the outer end. A nut 3 is attached to the inner end of the sub case. The threaded rod 4 consists of a threaded part and a solid part, and the threaded part is screwed into the nut 3 by a ball screw. Further, the solid portion is pivotally supported by a bearing 5 to the lid portion of the main case, and movement in the axial direction is inhibited. The weight 6 has a cylindrical shape and is fixed to the solid part of the threaded rod. The weight 6 has an annular stepped portion having a large and small diameter at one end, and a plurality of pins 7 are implanted at equal angular positions on the same circumference on the axial surface of the stepped portion. The oscillating body 8 is egg-shaped, and a through hole is formed at the end of the oscillator 8, which tapers into a small size, so that each of the pins 7
It is inserted into the main case with a sufficient gap so that it can come into contact with the inner wall of the main case and the circumferential side of the small diameter stepped portion of the weight. Further, by setting the gap between the pin 7 and the through hole and the position where the pin 7 is installed, the rocking body 8 may collide with the pin 7 within the gap other than the inner wall of the main case.

The present invention is constructed as described above. Both handles 1
A and 2a are used by connecting one to the structure and the other to piping. When a slow displacement occurs in the piping due to a temperature change, the weight rotates via the threaded rod due to the relative movement between the main case and the sub case, but since this movement is slow, there is no inertial resistance of the weight. First, even if the rocking body 8 comes into contact with the inner wall of the main case or the weight due to its own weight, the resistance is small so that no restraining action occurs. However, in the case of sudden vibrations caused by an earthquake, the weight dampens the reciprocating rotation due to its inertial resistance, thereby achieving a damping effect. At this time, the rocking body 8 is also urged to protrude in the radial direction by the centrifugal force, but in a low frequency band, the centrifugal force is small and collisions between the rocking body 8, the main case wall, and the weight are minor. Conversely, in a high frequency band, the vibration is high speed and small amplitude, so the oscillator 8 causes play within the gap between the through holes and becomes almost stationary. However, if the angular acceleration of the reciprocating weight increases due to resonance, the rocking body 8 violently collides with the inner wall of the main case, as shown in FIGS. 2 and 3, and the reaction also collides with the weight. At this time, the vibration energy of the weight is reduced due to energy loss due to the collision, and resonance is prevented.

As described above, in the present invention, normal vibrations are suppressed by inertial resistance, but in the case of resonance, resonance is prevented by energy loss due to collision.

〔effect〕

Unexamined Japanese Patent Publication No. 1977-1 was developed with the intention of improving a vibration damper that converts linear vibration into reciprocating rotational vibration of weights.
No. 124777 and Japanese Utility Model Application No. 138241/1983 are known, but both are of the friction brake type and have nothing to do with resonance. In contrast, the present invention handles excessive loads in the resonant frequency band by reciprocating collisions of multiple rocking bodies.
The feature is that it can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a front view of the present invention, FIG. 2 is a sectional view when the oscillator is in operation, and FIG. 3 is an operational view of the oscillator. 1... Main case, 2... Sub case, 3... Nut, 4... Threaded rod, 5... Bearing, 6... Weight, 7... Pin, 8... Rocking body.

Claims (1)

[Scope of utility model registration request] A cylindrical main case that has a handle at one end, a cylindrical sub-case that is inserted into the main case facing each other and has a nut at its inner end and another handle at its outer end, and a sub-case that is rotatably supported by the main case. A threaded rod with a threaded part that engages with a nut and a ball screw, a cylindrical weight that is fixed to the threaded rod and has an appropriate annular gap between it and the inner surface of the main case, and a cylindrical weight that extends outward in the axial direction of the weight with the same circumference. A plurality of pins are planted at equal angular positions, and a hole is drilled at a position off the center of gravity, and the pins are inserted with a sufficient gap between them, and the rotation of the weight connects the inner wall of the main case and the weight directly or through the pins. A vibration damping device consisting of a collidable rocking body.