JPS60100766A - Zero speed detector for rotating shaft - Google Patents

Abstract

PURPOSE:To detect the zero speed of a rotating shaft securely by generating a saw-tooth signal according to the rotation of the rotating shaft, and differentiating, detecting, and rectifying the saw-tooth signal. CONSTITUTION:A rotating disk 7 rotates according to the rotating shaft 1 and an eddy current type displacement gauge 8 generates a saw-tooth wave signal. This saw-tooth wave signal is amplified by an amplifier 9, differentiated by a differentiator 10, and further detected and rectified by a detector 11 and a rectifier 12 to generate an analog voltage proportional to the rotating speed of the rotating shaft 1. This analog voltage is inputted to an analog indicator.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for detecting zero speed of a rotating shaft in a rotating body such as a steam turbine, a fan, etc. Detection of the speed of a rotating shaft in a body is carried out as follows. In other words, as shown in FIG. Attach the magnetic pickup 3 to the peripheral surface of the gear 2, and input the output of the electromagnetic pickup 3 to the analog indicator 16 via the digital counter 4 and the F/V converter 5. However, in conventional speed detection devices such as those described above,
Output of electromagnetic pickup 3? ll]; I:f: The waveform is the same as shown in FIG. 2, and as the rotation of the single rotation axis l becomes smaller, the output voltage decreases and the pulse interval T increases.

For this reason, the digital counter 4 becomes difficult to operate in extremely low rotation conditions, and the analog circuit F/V converter 5
Mosaku v) 1 shi disappears. Therefore, analog indicator 6
Therefore, it is difficult to perform detection in an extremely low rotation state near zero speed of the fifth rotation axis I. and.

At present, there is no suitable method for detecting zero speed, and the current situation is that detection is hardly performed.

The present invention was made in consideration of the above-mentioned circumstances, and
The purpose is to provide a zero speed detection device for a rotating shaft that can reliably and easily detect the rotational state of the rotating shaft near zero speed.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Below, one embodiment of the present invention will be explained with reference to the drawings. FIG. 3 shows an example of the configuration of a zero speed detection device for a rotating shaft according to the present invention, and the same parts as those in FIG. 1 are indicated with the same symbol.

That is, at least a part of the outer periphery of the boat speed traction detection device ('!) of the present invention is formed in a sawtooth shape as shown in the figure (the teeth become gradually higher in the direction of rotation).

A rotary circle &7 is installed coaxially at the end of or between the shafts of the rotary shaft 1 as the object to be measured, and a rotary disk 70 is installed on the circumferential surface of the rotary disk 70 to measure its displacement as the rotary shaft rotates. Measuring and producing a sawtooth signal ) 6 eddy current displacement F! 1
8, and an amplifier 9 that amplifies the output from the displacement meter 8.
A differentiator IO that differentiates the output from this amplifier 9, a detector 11 that detects the outputs of this differentiator 10, and an analog instruction (not shown) that rectifies the output of this detector 11 and converts it into an analog signal. It is composed of a light adjusting device 12 that outputs an output to a meter. Note that the number of teeth of the rotary disk 7 can be arbitrarily set depending on the rotation speed of the rotation axis l.

Next, in the zero speed detection device with such a configuration, by installing a change f<z&18 on the circumferential surface of the rotating disk 7 whose outer periphery is saw-toothed, the When the rotation circle gi7 rotates (in the direction of the arrow shown in the third figure), the voltage output waveform of the five displacement sensor 8 becomes as shown in FIG. This is then amplified by the TIE amplifier 9 to form waveform B.

Next, if this waveform B is differentiated by the differentiator 10, the waveform C
becomes. In other words, the hatched part of waveform B is a straight line, so it becomes horizontal with a constant width, and the tooth switching part becomes vertical, resulting in a waveform in the opposite direction r (sharp pulse-like shape).
Enter lK.

Cut out the pulse wave in the opposite direction of waveform C to make it look like a waveform. Furthermore, this waveform is converted into an analog voltage EK proportional to the rotational speed by a rectifier I2, and this is input to an analog indicator (not shown) for indication.

As mentioned above, in the zero speed detection device of the present invention, the final indication value for speed detection is analog, so it is possible to visually confirm the decreasing state of the speed of the rotating shaft l, thereby ensuring that the speed near zero is detected. 3. In this case, with this method, when the shaft rotation speed approaches zero, the output becomes almost zero and it is difficult to judge whether it is completely zero, but it is possible to clearly indicate and record the state of decrease in speed. Therefore, it is extremely easy to predict zero velocity from this downward curve.

As described above, according to the present invention, it is possible to provide a highly reliable zero speed detection device for a rotating shaft that can reliably and easily detect the rotational state of a single rotating shaft in the vicinity of zero speed.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a conventional rotating shaft speed detection device, FIG. 2 is a diagram showing an output waveform of the electromagnetic pickup in FIG. 1, and FIG. 3 is a block diagram showing an embodiment of the present invention. Fourth
The figure is a waveform diagram for explaining the present invention in detail. 1... Rotating shaft, 7... Rotating disk %8... Displacement tracker 1.9... Amplifier, 10... Differentiator, 1)... Detector, 12... Rectifier. Applicant sub-agent Patent attorney Takehiko Suzue Continued from page 1 0 Inventor Kan Tokunaga

Claims (1)

[Claims] A rotating disk having at least a part of its outer periphery formed in a sawtooth shape and mounted coaxially with the rotational shaft pressure as the object to be measured; A displacement meter that generates a sawtooth signal, a differentiator that differentiates the output from this displacement 11, a detector that detects the output from this differentiator, and a rectifier that converts the output of this detector into an analog signal. 1. A zero speed detection device for a rotating shaft, comprising a rectifier.