JPH11160012A - Apparatus for measuring eccentricity amount of shaft of rotating body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable accurate measurement by providing a cycle calculation means for a rotating body, and a filter means set at an electric signal line for changing a pass frequency band by a cycle calculated by the cycle calculation means. SOLUTION: A rotation cycle of a rotating body 4 is converted to an electric signal by a rotation cycle detector 3 and transmitted to a rotation cycle operation circuit 5, whereby a rotation cycle T of the rotating body is calculated. An eccentricity amount operation means 6 calculates a rotation frequency (f)(=1/T) from the rotation cycle T and transmits a selector signal designating a low pass filter having a cut-off frequency fLP closest to the frequency (f) and exceeding the frequency (f) to a switch of a low pass filter means 7 of a cut-off frequency variable type. A gap length detector 2 converts a gap length between the gap length detector 2 and the rotating body 4 to an electric signal. The electric signal is filtered by the low pass filter selected by the switch and transmitted to the eccentricity operation circuit 6. An eccentricity amount of the rotating body 4 is derived accordingly.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in an apparatus for measuring the amount of eccentricity of a rotating body shaft such as a generator.

[0002]

2. Description of the Related Art FIG. 8 is a block diagram showing a conventional rotary body shaft eccentricity measuring device. In the figure, reference numeral 21 denotes a rotating body axis eccentricity calculating device, 22 denotes a gap length detector, 23 denotes a rotation cycle detector, and 24 denotes a rotating body. The rotator shaft eccentricity calculator 21 includes a rotation cycle calculator 25, an eccentricity calculator 26, and a fixed cutoff frequency low-pass filter 27.

Next, the operation will be described. The rotation cycle T of the rotating body 24 is converted into a voltage signal V1 by the rotation cycle detector 23, and transmitted to the rotation cycle calculation circuit 25, where the rotation cycle T is calculated. In the gap length detector 22, the gap length detector 2
The gap length between the rotating body 2 and the rotating body 24 is converted into an electric signal V2,
The electric signal V2 is filtered by a fixed cut-off frequency type low-pass filter 27 to become an electric signal V3, which is transmitted to the eccentricity calculating circuit 26. In the eccentricity calculating circuit 26,
The maximum gap length L _{MAX and the} minimum gap length L _MIN within the rotation period T calculated by the rotation frequency calculation circuit 25 are calculated from the electric signal V3, and the eccentricity L of the rotating body 24 is derived.

[0004]

Since the conventional rotating body shaft eccentricity measuring apparatus is constructed as described above, the rotating body 2
If there is a flaw or the like on the surface of No. 4, high-frequency noise is superimposed on the electric signal detected by the gap length detector 22. Therefore, the rotation period T of the rotating body 24 increases, and the rotation frequency f
Is reduced, noise lower than the cut-off frequency f _LP of the fixed cut-off frequency type low-pass filter 27 passes therethrough, so that the error of the calculated eccentricity L increases.

The present invention has been made to solve the above-described problems. Even when the rotation period T is increased and the rotation frequency f is decreased, the surface of the rotating body 24 may be damaged. It is an object of the present invention to obtain a rotating body shaft eccentricity measuring device which does not pass high frequency noise and does not cause an error in the calculated eccentricity L.

[0006]

According to a first aspect of the present invention, there is provided a rotating body shaft eccentricity measuring apparatus which converts a gap length between a gap length detector and a rotating body into an electric signal, and converts the electric signal. The eccentricity of the rotating body shaft is measured by transmitting the eccentricity to the eccentricity calculating means by an electric signal line. The means for calculating the cycle of the rotating body is provided on the electric signal line and calculated by the cycle calculating means. And a filter means capable of changing the pass frequency band according to the set period.

[0007] A rotating shaft eccentricity measuring apparatus according to a second aspect of the present invention uses a switched capacitor filter as the filter means.

A third aspect of the present invention provides a rotary shaft eccentricity measuring apparatus using a digital bandpass filter as a filter.

According to a fourth aspect of the present invention, there is provided an apparatus for measuring the amount of eccentricity of a rotating body shaft, wherein a rotation cycle calculating circuit for calculating a cycle of the rotating body is provided separately from the measuring apparatus for the amount of eccentricity of the rotating body shaft.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a rotating body shaft eccentricity measuring device according to the present invention. In the drawing, 1 is a rotating body shaft eccentricity calculating device, 2 is an air gap length detector, 3 is a rotation period detector, and 4 is a rotation. Body. The rotating shaft eccentricity calculating device 1 includes a rotation cycle calculating circuit 5,
It comprises an eccentric amount calculation circuit 6 and a variable cut-off frequency type low-pass filter section 7.

FIG. 2 is a block diagram showing the cut-off frequency variable low-pass filter section 7 in FIG. 1. In FIG. 2, a changeover switch 8 operated by a select signal S from an eccentricity amount calculating circuit 6 and a stepwise switch are shown. Low-pass filters 9a, 9b, 9c, 9d having different cutoff frequencies
It is composed of FIG. 3 is a flowchart showing the algorithm of the operation in the rotation period calculation circuit 5 and the eccentricity calculation circuit 6.

Next, the operation will be described. The rotation period T of the rotating body 4 is converted into an electric signal V1 by the rotation period detector 3,
The rotation period T is transmitted to the rotation period calculation circuit 5 and the time required for the rotator 4 to make one rotation, that is, the rotation period T is calculated (STE).
P100). The eccentricity calculation circuit 6 calculates the rotation frequency f (= 1 / T) from the rotation period T (STEP 101), and the low-pass filters (9a to 9c) having the cut-off frequency f _LP exceeding the rotation frequency f and closest to the rotation frequency f. 9d) is transmitted to the changeover switch 8 of the low-pass filter unit 7 with a variable cutoff frequency.

The changeover switch 8 selects a low-pass filter (one of 9a to 9d) specified by the selector signal S. It is determined whether or not the selected filter number is the same as the previously calculated one (STEP 103). If the selected low-pass filter is the same as the previously selected filter, the selector signal is not transmitted.

The gap length detector 2 converts the gap length between the gap length detector 2 and the rotating body 4 into an electric signal V2, and the electric signal V2 is converted into a low-pass filter (9a to 9d) selected by the changeover switch 8. ), And becomes V3, which is transmitted to the eccentricity amount calculation circuit 6. Eccentricity calculation circuit 6
, The rotation cycle T calculated by the rotation cycle calculation circuit 5
The maximum gap length L _{MAX and the} minimum gap length L _MIN are calculated from the electric signal V3 to derive the amount of eccentricity L of the rotating body 4 (STEP 102).

As described above, since the filter means having a mechanism capable of changing the pulse frequency band is provided, the rotation cycle T increases and the rotation frequency f decreases in the conventional rotary shaft eccentricity measurement apparatus. In this case, the high-frequency noise caused by the flaw on the surface of the rotating body that has passed through the fixed cut-off frequency type low-pass filter is filtered by the cut-off frequency variable low-pass filter unit 7, so that the eccentricity error becomes small. Thus, a highly reliable rotary shaft eccentricity measuring device can be obtained.

Embodiment 2 Hereinafter, a second embodiment of the present invention will be described with reference to the drawings. FIG. 4 is a configuration diagram showing a rotating body shaft eccentricity measuring device according to a second embodiment. In the drawing, 1 is a rotating body shaft eccentricity calculating device, 2 is a gap length detector, 3 is a rotation cycle detector, Is a rotating body. The rotating shaft eccentricity calculating device 1 includes a rotation cycle calculating circuit 5,
Eccentricity calculation circuit 6, switched capacitor filter 10
It is composed of

In the first embodiment, the eccentricity calculating circuit 6
To transmit the selector signal S to the variable cut-off frequency type low-pass filter unit 7 and select one of the fixed cut-off frequency type low-pass filters (9a to 9d) by the changeover switch 8 to remove high-frequency noise. As described above, in the present embodiment, the variable cutoff frequency type low-pass filter unit 7 is connected to the switched capacitor filter 10.
In the eccentricity calculating circuit 6, the clock signal CLK proportional to the rotation frequency f is transmitted to the switched capacitor filter 10, and the cutoff frequency f _{LP is changed} to the rotation frequency f
, The accuracy of the calculated eccentricity L can be improved.

Next, the operation will be described. FIG. 5 is a flowchart showing the algorithm of the operation in the rotation period calculation circuit 5 and the eccentricity calculation circuit 6. The rotation cycle T of the rotating body 4 is converted into an electric signal V1 by the rotation cycle detector 3 and transmitted to the rotation cycle calculation circuit 5, and the time required for the rotating body 4 to make one rotation, that is, the rotation cycle T is calculated. (STEP200). A rotation frequency f (= 1 / T) is calculated from the rotation cycle T of the eccentric amount calculation circuit 6 (STEP 20).
1) At the same time, the amount of eccentricity is calculated (STEP 202), and a signal that passes the rotation frequency or lower is transmitted to the switched capacitor filter 10.

Embodiment 3 Embodiment 3 of the present invention will be described with reference to FIG. In the second embodiment, the case where the switched capacitor filter 10 is provided as a filter to remove high-frequency noise has been described. However, the digital bandpass filter 11 having the rotation frequency f as the pass frequency f _BP is provided instead of the switched capacitor filter 10. Thereby, high frequency noise and low frequency noise with respect to the rotation frequency f can be removed, and the accuracy of the calculated eccentricity can be improved.

Embodiment 4 Embodiment 4 of the present invention will be described with reference to FIG. In the first to third embodiments, in order to transmit the rotation period T to the eccentricity amount calculation circuit 6, the rotation period detector 3 converts the rotation period T into an electric signal V1. To five,
The case where the rotation period T is calculated by the rotation period calculation circuit 5 has been described. However, as shown in FIG. A transmission path for the purpose of inputting the rotation period T to the eccentricity amount calculation circuit 6 by transmission from the rotation period calculation circuit 12 as a device may be provided. With such a configuration, the rotation period detector 3 becomes unnecessary, the structure can be simplified, and a device with reduced installation area at low cost can be obtained.

[0021]

According to the rotating body shaft eccentricity measuring apparatus according to any one of the first to third aspects of the present invention, the gap length between the gap length detector and the rotating body is converted into an electric signal. A means for measuring the amount of eccentricity of the rotating body shaft by transmitting a signal to an eccentricity amount calculating means by an electric signal line, wherein the means for calculating a cycle of the rotating body, and a cycle calculating means provided on the electric signal line Filter means that can change the pass frequency band according to the cycle calculated by the above, so that even if the rotation cycle of the rotating body whose eccentricity is measured becomes longer and the rotating frequency becomes lower, it is present on the surface of the rotating body. Since noise generated due to scratches or the like can be efficiently removed, highly accurate eccentricity measurement can be performed.

According to the rotating body shaft eccentricity measuring apparatus according to claim 4 of the present invention, the rotating cycle calculating circuit for calculating the cycle of the rotating body is provided separately from the rotating body shaft eccentricity measuring apparatus.
The structure can be simplified, and a device with a reduced installation area at low cost can be obtained.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating a rotating body shaft eccentricity measuring device according to a first embodiment of the present invention;

FIG. 2 is a configuration diagram illustrating a filter unit according to the first embodiment of the present invention.

FIG. 3 is a flowchart illustrating an algorithm of an operation according to the first embodiment of the present invention.

FIG. 4 is a configuration diagram showing a rotating body shaft eccentricity measuring device according to a second embodiment of the present invention.

FIG. 5 is a flowchart showing an operation algorithm according to the second embodiment of the present invention.

FIG. 6 is a configuration diagram showing a rotating body shaft eccentricity measuring device according to a third embodiment of the present invention.

FIG. 7 is a configuration diagram illustrating a rotating body shaft eccentricity measuring device according to a fourth embodiment of the present invention;

FIG. 8 is a configuration diagram showing a conventional rotating body shaft eccentricity measuring device.

[Explanation of symbols]

2 air gap length detector, 4 rotators, 6 eccentricity calculation means,
7 filter means, 10 switched capacitor filter, 11 digital bandpass filter, 12 rotation cycle calculation circuit.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Keishi Aoki 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric Corporation

Claims (4)

[Claims] 1. An eccentricity of a rotating body shaft is measured by converting a gap length between a gap length detector and a rotating body into an electric signal and transmitting the electric signal to an eccentricity calculating means by an electric signal line. In the device, the means for calculating the cycle of the rotating body, and provided on the electric signal line,
A rotator shaft eccentricity measuring device, comprising: a filter means for changing a pass frequency band according to the cycle calculated by the cycle calculating means. 2. An apparatus for measuring the amount of eccentricity of a rotating body shaft according to claim 1, wherein a switched capacitor filter is used as the filter means. 3. An apparatus according to claim 1, wherein a digital band-pass filter is used as the filter means. 4. The rotating cycle calculating circuit for calculating the cycle of the rotating body is provided separately from the rotating body shaft eccentricity measuring device. Rotational shaft eccentricity measurement device.