JPS6133343Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a device for preventing vibrations of piping, etc. in power plants, chemical plants, etc.

There are many types of vibrations, ranging from vibrations caused by earthquakes to microvibrations caused by equipment with rotating bodies. Vibrations caused by earthquakes generally target a frequency of 3Hz to 33Hz, and some control devices for this use use the inertial resistance of weights as the main damping force.

Conventional vibration damping devices target vibrations in these frequency ranges, and do not take into account continuous micro-vibrations. Therefore, cracks occur in the connection parts and all the engaging parts of the device due to the reaction force of the micro-vibration, and in order to prevent the micro-vibration from being transmitted to the main body of the device, the engaging parts of the pull fittings provided at both ends of the main body There is also a structure in which a slight gap is provided between the two and the micro-vibration is absorbed by the gap, but this has the problem that the contact part is worn out by the micro-vibration.

The present invention was devised in view of the above problems, and by interposing a thin metal wire entanglement between the nut and one of the supporting members, micro vibrations are absorbed by the contact friction between the thin metal wires. It is something to do.

A fine metal wire entanglement is made by weaving stainless steel wire into knit stripes and compressing it.The load-deflection curve shows large hysteresis due to the friction between the steel wires, making it suitable for absorbing minute vibrations.

Embodiments of the present invention will be described below with reference to the figures. The main cylinder 1, which is a first support member, is composed of a large diameter part 1a and a small diameter part 1b, and a lid 2 having a handle 2a is fixed to the end of the large diameter part. The small diameter portion 1b is inserted into the sub cylinder 3 so as to be freely movable in the axial direction.

A handle 4 is attached to the outer end of the secondary cylinder 3, which is the second support member.
A lid 4 with a is fixed. The outer end of the shaft 5 is fixed to the inner center of the lid of the sub-cylinder 3. The inside of the shaft is axially movably inserted into a cylindrical case 6 which is axially movably inserted into the sub-cylinder. The shaft 5 has a flange 5a at its center, and thin metal wire entanglements 7 are inserted into cases 6 on both sides of the flange 5a.

An inner cylinder 8 is fixed to the inner end of the case 6, and the inner side of the inner cylinder is inserted into the main cylinder small diameter portion 1b so as to be freely movable in the axial direction, and a ball nut 9 is provided at the inner end.

The fixed wheel 10 is fixed to the main cylinder on the inside of the cover of the large diameter portion 1a, has a bearing hole in the center, and is provided with an annular friction surface 10a on the inside.

One end of the central shaft 11 is rotatably supported in a bearing hole of a fixed shaft, and the other end is a threaded rod of an appropriate length and is screwed into the ball nut 9. Inside the main cylinder large diameter portion 1a, a flywheel 12 is fixed to the central shaft 11, and a distance scara 13 is inserted between the flywheel and the fixed ring.
A nut 14 is attached to the end of the central shaft. That is, the central shaft 11 is connected to the nut 14 that holds the fixed ring 10.
It is positioned in the axial direction by the distance scara 13 and the main cylinder, but it can be rotated in forward and reverse directions by moving the main cylinder and the sub-cylinder in and out relative to each other.

The movable ring 15 is slidably inserted into the distance scara 13, has an annular friction surface 15a corresponding to the annular friction surface 10a of the fixed ring 10, and has a spring bearing ring 15b mounted on the opposite side. Correspondingly, the flywheel 12 is actually provided with a spring receiving collar 12a, and a spring 16 is inserted between the spring receiving collar 12a. Moreover, conical recesses are provided at corresponding positions on the opposing surfaces of the movable ring 15 and the flywheel 12, and a ball 17 is inserted between the two. The movable ring 15 is constantly attached to the flywheel 12 via a ball 17 by a spring 16, leaving an appropriate gap 18 between the two annular friction surfaces 10a, 15a. Further, a set screw 19 is formed by drilling a radial screw hole in a part of the large diameter portion 1a and screwing it into the hole.
The movable ring 15 can be fixed to the main cylinder if necessary.

The present invention is constructed as described above, and has two handles 2.
One of a and 4a is connected to the construct, and the other is connected to the tubing system. When the tube is at rest, the vibration isolator is also at rest, leaving a gap 18. Now, when the pipe system moves slowly due to temperature changes, the sub cylinder 3 moves slowly with respect to the main cylinder 1, the ball nut 9 moves together with this, and the flywheel 12 turns. However, since the turning speed is slow, the movable wheel 15 also turns integrally with the flywheel, so that the displacement of the pipe system is not hindered. However, when rapid vibrations occur in the pipe system due to an earthquake or the like, the flywheel 12 repeats rapid reciprocating rotation, but the movable wheel 1
5 cannot completely follow it due to inertia. In either case of forward or reverse rotation, the ball 13 rides on the slope of the recess and pushes the movable ring 15 toward the fixed ring 10.
As a result, a contact friction force is repeatedly exerted between the two wheels, and a vibration damping effect is produced. These anti-vibration effects are mainly aimed at vibrations caused by earthquakes and the like.

Due to the presence of the fine metal wire entanglement body 7, the minute vibrations generated from equipment etc. are absorbed by the friction between the shaft 5 and the case 6, which prevents the minute vibrations from being transmitted to the central shaft 11. There isn't. Afterwards,
The slight vibration is caused by the inertia resistance of the flywheel 12 and
Since the vibration is not damped by the control force of the movable wheel 15, the braking member has no effect.

In addition to the micro-vibration absorbing function, the present invention has a function of lowering the natural frequency of the device as a whole and reducing rigidity in a high frequency range. In other words, while this type of vibration isolator requires a large inertial mass in the low frequency range, the resulting dynamic spring constant tends to be excessive in the high frequency range. The purpose is to increase the dynamic spring constant by decreasing the number of dynamic spring constants, prevent excessive dynamic spring constants from occurring by reducing the stiffness in the high frequency range, and keep the stiffness in the low frequency range to the same level.

As described above, the present invention has a simple structure in which the thin metal wire entanglement body 7 is connected in series in a conventional vibration damping device, and the device can be isolated from minute vibrations. There was no wear and tear. Moreover, the spring stiffness of the device against relatively low cycle vibrations can be increased, which allows the flywheel 12 to be made smaller.

[Brief explanation of drawings]

The drawing is a front view showing an example of implementation of the present invention. 1...Main cylinder, 3...Sub-tube, 5...Shaft, 7
...Metal thin wire entwined body, 9...Ball nut, 11...
...Central axis, 12...Flywheel.

Claims (1)

[Scope of utility model registration request] The relative reciprocating motion in the axial direction of the first and second support members, each of which has an outer end connected to a structure or an object to be vibration-isolated, is converted into a relative rotational motion with respect to the nut of a threaded rod that is threaded into the nut. 1. A vibration isolator for controlling a vibration isolator, characterized in that a thin metal line body is interposed between the nut and one of the support members that rotates the nut in an axial direction.