JP2511983Y2 - Fluid dynamic vibration absorber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a fluid dynamic vibration reducer.

[Conventional technology]

FIG. 2 shows a system diagram of a conventional fluid dynamic vibration reducer. As shown in the figure, this device is a U-shaped tank in which the lower parts of the two vertical tanks 1a and 1b are connected by a communication tank 1, and generally water 3 is put inside. There is. Airtight chambers 2a and 2b are independently provided at the upper parts of the left and right vertical tanks, and in the airtight chambers 2a and 2b, injection vent pipes 4a and 4b for injecting compressed air are provided at the upper part, and one is provided at the center. It is connected to the injection tube 4 that has been made into a material. Injection ventilation pipes 4a, 4b are airtight chambers 2a, 2b
Forming a ventilation pipe that communicates with each other. The injection pipe 4 has a pressure reducing valve 5 for adjusting the injection air pressure, and its end portion is connected to a compressor 6 for producing compressed air. Left and right airtight chambers 2a, 2
At the upper part of b, exhaust vent pipes 7a, 7b for exhausting air in the airtight chamber are further provided.
Is provided, and the exhaust pipe 7 is integrated in the central portion. The exhaust ventilation pipes 7a, 7b form a ventilation pipe that connects the airtight chambers 2a, 2b. The exhaust pipe 7 is provided with a pressure switch 8 that operates at a set pressure value, and then an electromagnetic valve 9 that opens and closes the valve with the pressure switch 8.

In this fluid dynamic vibration absorber, the natural frequency of the dynamic vibration absorber is tuned to the frequency of the excitation source to be damped. The natural frequency of the dynamic vibration absorber is adjusted by adjusting the pressure in the airtight chambers 2a and 2b.
Based on the relationship between the natural frequency of the dynamic vibration absorber and the pressure of the airtight chambers 2a and 2b, which was verified in advance, as shown in Fig. 3, the compressed air should be tuned so that the natural frequency of the dynamic vibration absorber is tuned to the frequency to be damped. The pressure reducing valve 5 for adjusting the injection and the pressure switch 8 for adjusting the discharge of the airtight chamber pressure are manually adjusted to keep the pressure in the airtight chamber at a constant set pressure value. If the temperature changes, etc., the airtight chambers 2a, 2b
Is lower than the set pressure, compressed air is automatically injected from the pressure reducing valve 5. Conversely, when the airtight chamber pressure is higher than the set pressure, the pressure switch is operated, and at the same time, the solenoid valve 9 is operated to increase the pressure. Is discharged. This operating mechanism keeps the set pressure constant at all times.

[Problems to be solved by the device]

In a ship or the like, the rotation speed of an excitation source such as a main engine and a propeller changes every moment, and the vibration frequency changes accordingly. However, since the conventional dynamic vibration absorber is designed to maintain its natural frequency constant for vibration damping, the vibration damping effect cannot be obtained when the vibration frequency of the excitation source fluctuates.

The present invention is intended to provide a dynamic vibration absorber that can obtain a vibration damping effect even when the frequency of the excitation source changes.

[Means for solving the problem]

The present invention solves the above-mentioned problems, and comprises a vertical tank at both ends and a communication tank communicating with each other at the bottom, leaving U in the airtight chamber above the vertical tank to store liquid inside. V-shaped communication pipe type tank, an injection pipe for injecting compressed air into the airtight chambers by a compressor through an injection airflow pipe that communicates between the airtight chambers, and an air discharge pipe that communicates between the airtight chambers. In a fluid dynamic vibration absorber having an exhaust pipe for discharging air from a closed chamber, means for detecting the frequency of the excitation source, and the above-mentioned detection in the relationship between the natural frequency of the dynamic vibration absorber and the pressure in the airtight chamber which have been verified in advance. Means for calculating the set value of the airtight chamber pressure by applying the determined frequency,
The means for detecting the actual pressure in the airtight chamber, the electromagnetic pressure reducing valve for injection provided in the injection pipe, the electromagnetic valve for discharge provided in the exhaust pipe, and the actual pressure in the airtight chamber are always calculated as described above. The present invention relates to a fluid dynamic vibration reducer including a controller that controls the injection electromagnetic pressure reducing valve and the discharge electromagnetic valve so that the airtight chamber pressure is set to the set value.

[Action]

In the fluid dynamic vibration absorber of the present invention, the vibration frequency of the excitation source is detected, and the vibration frequency of the excitation source is applied to the relationship between the natural frequency of the dynamic vibration absorber and the airtight chamber pressure that has been previously tested,
The set value of the pressure in the hermetic chamber is automatically calculated, and the electromagnetic pressure reducing valve for injection and the electromagnetic valve for discharge are controlled by the controller so that the pressure in the hermetic chamber is always matched with the calculated value for the pressure in the hermetic chamber. As a result, the vibration damping effect can be obtained even when the frequency of the excitation source fluctuates.

〔Example〕

FIG. 1 shows a system diagram of an embodiment of the fluid dynamic vibration reducer of the present invention. As shown in the figure, the lower parts of the two vertical tanks 1a, 1b on the left and right are connected by the communication tank 1 to form a U-shaped tank as a whole, and the airtight chambers 2a, 2b are provided on the upper parts of the left and right vertical tanks 1a, 1b. In addition, an injection pipe 4 for injecting compressed air, an injection ventilation pipe 4a, 4b and an exhaust exhaust pipe 7, and an exhaust ventilation pipe 7a, 7b are provided from the upper part of the right and left vertical tanks respectively. This is the same as the conventional device in that the air in the airtight chambers on both sides is connected by connecting the respective tubes of 4b and the exhaust ventilation pipes 7a, 7b. In the present invention, in order to tune the natural frequency of the fluid dynamic vibration absorber to the changing vibration frequency of the excitation source, a counter circuit 11 for detecting and counting the rotation number of the excitation source, for example, the propeller shaft 19 of the ship, by the rotation detector 10. The frequency of the exciting force is calculated from this count value, and the set value of the airtight chamber pressure is calculated from the relationship between the natural frequency of the dynamic vibration absorber and the airtight chamber pressure that has been verified in advance. At the same time, the pressure detector 12 and the pressure detector amplifier 13 detect the actual pressure in the hermetic chamber. In order to match the airtight chamber pressure detected in this manner with the airtight chamber pressure set value calculated from the frequency of the excitation source, the injection solenoid valve operating amplifier 17 from the controller 18 is supplied.
An ON / OFF command is sent to one of the exhaust solenoid valve operational amplifiers 15 to activate the injection electromagnetic pressure reducing valve 16 or the exhaust electromagnetic valve 14, which causes the tank's natural vibration to fluctuate with the vibration frequency of the excitation source. Automatic tuning of numbers. With the above-described device, it is possible to eliminate the vibration generated from the propeller shaft of a ship whose number of revolutions changes every moment.

In the above embodiment, the excitation force generated from the propeller shaft of the ship was described as an example, but the present invention is not limited to the propeller shaft of the ship, and can be applied not only to the ship, but also to the vibration damping of land structures. Applicable. Further, the frequency of the excitation source may be calculated and used from the output of a vibrometer such as an accelerometer.

[Effect of device]

In the present invention, the frequency of the excitation source of the structure is detected, and the airtight chamber pressure is automatically controlled so that the natural frequency of the fluid dynamic vibration absorber is always matched with this frequency.
Even if the frequency of the excitation source changes, the vibration of the structure generated by this excitation source can be damped.

[Brief description of drawings]

FIG. 1 is a system diagram of an embodiment of the present invention, FIG. 2 is a system diagram of a conventional technique, and FIG. 3 is a relationship diagram between the natural frequency of a dynamic vibration absorber used in the above-mentioned conventional technique and the pressure in an airtight chamber. . 1 ... Communication tank, 1a, 1b ... Vertical tank, 2a, 2b ... Airtight chamber, 3 ... Liquid in tank (for example, water), 4a, 4b ... Injection vent pipe, 4 ... Injection pipe, 5 ...... Reducing valve, 6 ...... Pressure air source (compressor) 7a, 7b ...... Exhaust vent pipe, 7 ......
Exhaust pipe, 8 ... Pressure switch, 9 ... Solenoid valve, 10 ... Rotation detector, 11 ... Rotation counter circuit, 12 ... Pressure detector, 13 ... Pressure detector amplifier, 14 ... Discharge Solenoid valve, 15 …… Discharge solenoid valve actuation amplifier, 16 …… Injection solenoid pressure reducing valve, 17 …… Injection solenoid pressure reducing valve actuation amplifier, 18 …… Controller, 19 …… Rotator shaft (propeller shaft).

Claims (1)

(57) [Scope of utility model registration request] Claim: What is claimed is: 1. A U-shaped communicating tube type tank comprising a vertical tank at both ends and a communicating tank communicating with each other at the bottom, and leaving liquid in the airtight chamber at the upper part of the vertical tank to store a liquid therein.
An injection pipe for injecting compressed air into the both airtight chambers by a compressor through an injection ventilation pipe that connects the both airtight chambers,
In a fluid dynamic vibration absorber having an exhaust pipe for exhausting air from the airtight chambers through an exhaust ventilation pipe that communicates the airtight chambers, a means for detecting the frequency of an excitation source, the previously tested dynamic vibration absorber Means for calculating the set value of the airtight chamber pressure by applying the detected frequency to the relationship between the natural frequency of the container and the airtight chamber pressure, the means for detecting the actual airtight chamber pressure, the injection pipe Electromagnetic pressure reducing valve provided on the exhaust pipe, the electromagnetic discharge valve provided on the exhaust pipe, and the electromagnetic reducing pressure for injection so that the actual airtight chamber pressure is always the calculated airtight chamber pressure set value. A fluid dynamic vibration reducer comprising a valve and a controller for controlling the discharge solenoid valve.