JP2551119B2 - Shaft vibration self-diagnosis device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a shaft vibration self-diagnosis device for detecting shaft vibration of a rotary drive shaft of a rotary machine or the like.

[Prior Art] As a rotary drive shaft of a rotary machine or the like, a non-contact type (or contact type) detection device such as a probe that detects shaft vibration of the rotary drive shaft as analog vibration data, and a vibration detected by this device. A shaft vibration detection device has been developed which is composed of a data processor for analog processing of data.

[Problems to be Solved by the Invention] However, if the shaft vibration is detected in analog and processed in analog like this type of device, an increase in the shaft load at the time of start is erroneously determined as vibration. Sometimes
It was not enough to obtain highly accurate vibration data.

[Means for Solving the Problem] The present invention has an object to solve the above-mentioned problems, and a vibration detecting unit that detects a voltage fluctuation based on a change in a relative distance from a rotary drive shaft as a vibration value, and a constant (necessary). And the A / D converter that sequentially quantizes the detected voltage at a cycle that is less than the reciprocal of twice the frequency) and the coded signal of this converter is stored in memory and the maximum value of those coded signals is calculated. After subtracting the minimum value, the amplitude value is calculated and stored in the memory of the FIFO (first-in-first-out [same as below]), then the average value is obtained, and the average value is multiplied by the sensitivity constant of the detecting means. The controller for obtaining the actual vibration value of the rotary drive shaft constitutes a shaft vibration self-diagnosis device.

[Operation] When the detection means detects a voltage fluctuation based on a change in the relative distance to the rotary drive shaft of a rotating machine or the like as a vibration value and inputs the detected voltage to the A / D converter, the A / D converter , The detected voltage is sampled at a constant sampling cycle, sequentially quantized, and input to the controller. Controller is A / D
After storing the coded signals of the converter in the memory, the minimum value is subtracted from the maximum value of these coded signals to calculate the amplitude, and the calculated values are sequentially stored in the memory of the FIFO. After that, the average value of the stored operation values is obtained, and the obtained average value is multiplied by the sensitivity constant of the detecting means to obtain the actual vibration value of the rotary drive shaft.

That is, the A / D converter samples the detected voltage at a constant cycle, sequentially quantizes it, inputs it to the controller, and grasps the fluctuation state of the detected voltage with high accuracy, while storing the encoded signal in the memory, After subtracting the minimum value from the maximum value of the encoded signal to calculate the amplitude and storing it in the memory of the FIFO, the average value is obtained and the average value is multiplied by the sensitivity constant of the detecting means to determine the actual value of the rotary drive shaft. Abnormal noise that occurs suddenly in the encoded signal input to the controller is obtained by obtaining the vibration value, and the actual vibration value of the rotary drive shaft is qualitatively and quantitatively grasped.

[Embodiment] A preferred embodiment of the present invention will be described below with reference to the accompanying drawings.

Now, in this embodiment, the rotary drive shaft 11 of the rotary machine has a proper distance S from the rotary drive shaft 11 as shown in FIG. A vibration detecting means 12 for detecting a change in the voltage as a change in the voltage is installed. In the embodiment, the vibration detection means 12 is composed of a probe 13 that detects and outputs a change in distance as a change in voltage, and an amplifier 14 that amplifies the output voltage of the probe 13, and the detection amplified by the amplifier 14 is performed. The voltage is input to the controller 16 through the A / D converter 15. The controller 16 is composed of a PIO 17, a CPU 18, and a memory unit (RAM: write / read memory at any time) 19, and the CPU 18 is configured to execute data input / output and control signal input / output with the PIO 17 and memory unit 19. I am doing it. On the other hand, the A / D converter 15 is configured to sample the detected voltage at a constant sampling period T ₁ and sequentially quantize it, and input the encoded signal to the controller 16. That is, the A / D converter 15 is configured to sample the detected voltage at the sampling period T ₁ and sequentially quantize it as shown in FIG.

If the number of memory inputs is set to 8 bits and 128 are provided,
The memory unit 19 of the controller 16 can input 128 coded signals quantized at constant sampling intervals for one cycle T of the detected voltage.

On the other hand, the CPU 18 is configured to execute the following control.

First, when the coded signals are sequentially input to the memory 20 capable of storing 128 pieces at a constant sampling interval T ₁ , the CPU 18 subtracts the minimum value from the maximum value of the input coded signals to obtain the amplitude value W. After this, the CPU 18 is shown in FIG. 4 (1), (2),
As shown in (3), ... (N), 16 average values are obtained while sequentially storing the obtained amplitude values W in the memory 21 of another FIFO (first in / first out) capable of storing 16. The average amplitude value W is multiplied by the sensitivity multiplier of the probe 13 to obtain the actual vibration value of the rotary drive shaft 11, and when the actual vibration value exceeds the set value X, it is output to a monitor (not shown). Execute "light failure display", and if the actual vibration value exceeds the set value X (eg 40 microns) and exceeds the set value Y (eg 60 microns) larger than the set value X, execute "serious failure display". Let However, CPU 18 is the above rotary drive shaft 1
When 1 is started, that is, when the rotating machine 1 is started, the memories 20 and 21 are all cleared to start from "0".

With the above configuration, first, the shaft runout at the start of the rotary drive shaft 11, which is rotatably supported by the floating bearings at the start, is not mistakenly judged to be abnormal shaft vibration, and the shaft is driven at the sampling cycle T ₁ . Since the vibration can be detected finely, it is not necessary to detect only the peaks or the valleys of the cycle of the vibration and determine the vibration. Therefore, the reliability and accuracy of vibration detection are greatly improved.

Further, by calculating the average value, it is possible to reduce the sudden change in the detection data, so that the vibration can be detected without being affected by noise or the like.

By the way, it is possible to reduce the amount of sudden change in the detected data by calculating the average value, but the coded signal detected by the A / D converter 15 contains a particularly large spike-like electrical noise. Therefore, as a countermeasure against this, when the amplitude value W obtained by subtracting the minimum value from the maximum value of the input coded signal is a set value Z (for example, 120 microns) or more, the set value Z is treated as To prevent.

[Effects of the Invention] As is clear from the above description, the present invention exhibits the following excellent effects.

Vibration detection means for detecting a voltage fluctuation based on a change in the relative distance to the rotary drive axis as a vibration value, and an A / D converter for sequentially quantizing the detected voltage at a fixed cycle, and
The coded signals of the converter are stored in a memory, the minimum value is subtracted from the maximum value of the coded signals to calculate an amplitude value and the amplitude value is stored in the memory of the FIFO, and then an average value is obtained. Since a shaft vibration self-diagnosis system is configured with a controller that obtains the actual vibration value of the rotary drive shaft by multiplying by the sensitivity constant of, the reliability and accuracy of vibration detection can be greatly improved.

[Brief description of drawings]

FIG. 1 is a detailed view of essential parts showing a preferred embodiment of the present invention, FIG. 2 is a schematic view showing changes in detection voltage with respect to probe time and sampling intervals, and FIGS. 3 and 4 are memories and memories thereof. It is a schematic diagram which shows the input state of the data with respect to. In the figure, 11 is a rotary drive shaft, 12 is a vibration detecting means, 15 is an A / D converter, and 16 is a controller.

Claims (1)

(57) [Claims] 1. A vibration detecting means for detecting a voltage fluctuation based on a change of a relative distance from a rotary drive shaft as a vibration value, and an A / D converter for sampling a detected voltage at a constant sampling cycle and sequentially quantizing the detected voltage. , Store the encoded signals of the converter in the memory, subtract the minimum value from the maximum value of the encoded signals to calculate the amplitude value, store it in the FIFO (first-in-first-out) memory, and then average. A shaft vibration self-diagnosis device, comprising: a controller for obtaining a value and multiplying the average value by a sensitivity constant of the detecting means to obtain an actual vibration value of the rotary drive shaft.