JPH07260631A - Abnormality detector - Google Patents

Abstract

PURPOSE:To provide an abnormality detector for detecting AE from a shaft rotating at high speed with high sensitivity. CONSTITUTION:The abnormality detector comprises a nonrotating annular body 5 being applied to the outer periphery 2a of a rotary shaft 2 through an oil film 3, and an AE sensor 6 fixed to the annular body 5. The rotary shaft 2 rotates at high speed while the AE sensor 6 remains stationary. Since the AE sensor 6 detects AE from the rotary shaft 2 only through the oil film 3 and the annular body 5, attenuation of the AE is suppressed as compared with the case where the AE is detected through a rolling bearing 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an abnormality detecting device for detecting an abnormality of a rotary shaft or a mechanical element such as a gear attached to the rotary shaft.

[0002]

2. Description of the Related Art Conventionally, as this type of abnormality detecting device,
Some AE sensors measure AE (acoustic emission) generated from rotating shafts and gears. For example, telemeters are used to transmit signals representing AE, and rolling bearings that support the shaft have AE sensors. There is a device in which an AE is measured via this AE sensor.

[0003]

However, in order to transmit the envelope detection waveform of the AE with the telemeter, the sensor, the amplifier, the filter, the detector, and the telemeter must be directly attached to the shaft or the gear. Therefore, when the shaft or gear rotates at high speed,
Since these parts are required to have high acceleration resistance performance, there is a problem that it is difficult to apply them to a rotating shaft that rotates at high speed.

Further, when AE is measured through the rolling bearing, the AE generated on the shaft is detected by the AE sensor via the inner ring, rollers, cage, outer ring and housing of the bearing. Has a drawback that the transmission path of the AE is complicated, the AE is attenuated, noise is increased, and the detection sensitivity of the AE is lowered.

Therefore, an object of the present invention is to provide an abnormality detecting device capable of detecting AE from a rotating shaft rotating at high speed with high sensitivity.

[0006]

In order to achieve the above object, an abnormality diagnosis device of the present invention is an abnormality detection device for detecting an abnormality of a rotary shaft or a mechanical element provided on the rotary shaft. A non-rotating annular body mounted on the outer periphery through an oil film, and A attached to the annular body.
It is characterized by having an E sensor.

According to the present invention, since the AE sensor is not directly attached to the rotary shaft but is attached to the non-rotating annular body mounted through the oil film, the AE sensor is stationary even if the rotary shaft is rotated. Therefore, even if the rotating shaft rotates at high speed, A
Large acceleration is not applied to the E sensor.

Further, since the AE sensor detects the AE from the rotating shaft only via the oil film and the annular body, compared with the conventional example in which the AE from the rotating shaft is received via the AE sensor attached to the rolling bearing. , AE is less attenuated, and the sensitivity for detecting AE is improved.

Therefore, according to the present invention, the AE from the rotating shaft rotating at a high speed can be detected with high sensitivity.

[0009]

The present invention will be described in detail below with reference to the embodiments shown in the drawings.

FIG. 1 shows an embodiment of the abnormality detecting device of the present invention. In this embodiment, a stationary annular body 5 mounted on an outer circumference 2a of a rotary shaft 2 to which a gear 1 is fixed via an oil film 3
And an AE sensor 6 fixed to the outer peripheral surface 5a of the annular body 5. The annular body 5 is made of a copper alloy and looks like a plain bearing, but does not support the rotating shaft 2 and therefore does not function as a bearing. A load is applied to the annular body 5 in the direction indicated by the arrow A in FIG. 1 as needed, and the thickness of the oil film 3 is about several μm. The oil film 3 having a thickness of about several μm is attached to the rotary shaft 2
The AE from can be propagated particularly well.

A rolling bearing 7 for supporting the rotary shaft 2 is provided between the annular body 5 and the gear 1. The rolling bearing 7 is composed of an inner ring 7a, rollers 7b, an outer ring 7c, etc., and is attached to a housing 8. The housing 8 surrounds the mechanical elements including the rotary shaft 2, the gear 1, the gear 10 meshed with the gear 1, the rotary shaft 11, and the like.

As shown in FIG. 2, a preamplifier 21, a bandpass filter 22, a main amplifier 23, an envelope detection circuit 24, a comparison circuit 25, and a computer 26 are sequentially connected to the AE sensor 6.

In the abnormality detecting device having the above-mentioned structure, the AE generated from the gear 1 and the rotary shaft 2 is detected by the AE sensor 6 through the relatively thin oil film 3 of about several μm and the annular body 5. The AE signal from the AE sensor 6 is amplified by the preamplifier 21, and the bandpass filter 22
Then, only the frequency component of a predetermined band is passed, further amplified by the main amplifier 23, and envelope-detected by the envelope detection circuit 24. Then, the envelope-detected AE signal is compared with a predetermined threshold value by the comparison circuit 25,
When the threshold value is exceeded, the comparison circuit 25 outputs an alarm signal. Then, the computer 26 receiving this alarm signal issues an externally recognizable alarm. The AE signal exceeding the threshold value is caused by cracks, scratches, or distortions of the rotary shaft 2 and the gear 1.

In the abnormality detecting device of this embodiment, since the AE sensor 6 is attached to the annular body 5 which is attached to the rotary shaft 2 through the oil film 3, even if the rotary shaft 2 rotates at high speed, the AE sensor 6
The sensor 6 does not rotate. Therefore, even if the rotary shaft 2 rotates at a high speed, the AE sensor 6 is not required to have a large anti-acceleration performance. Therefore, this embodiment can also be applied to detection of abnormality of the rotating shaft 2 rotating at high speed.

Further, the AE sensor 6 is the A from the rotary shaft 2.
Since E is received only through the relatively thin oil film 3 of about several μm and the annular body 5, the AE from the rotary shaft 2 is attenuated as compared with the conventional example in which the AE from the rotary shaft is received via the rolling bearing. Is small, and AE from the rotary shaft 2 can be detected with high sensitivity.

Therefore, according to this embodiment, the AE from the rotating shaft 2 or the gear 1 that rotates at a high speed can be detected with high sensitivity.

In this embodiment, a load is applied to the annular body 5 to improve the AE propagation performance, but it is not always necessary to apply a load to the annular body 5.

[0018]

As is apparent from the above, in the abnormality detecting device of the present invention, since the AE sensor is attached to the non-rotating annular body mounted on the rotating shaft through the oil film, the rotating shaft rotates at high speed. However, the AE sensor remains stationary.

Further, since the AE sensor detects the AE from the rotating shaft via only the oil film and the annular body, the AE sensor detects the AE from the rotating shaft via the rolling bearing as compared with the conventional example. Attenuation is small. Therefore, A from the rotation axis
E can be detected with high sensitivity.

Therefore, according to the present invention, the AE from the rotating shaft rotating at a high speed can be detected with high sensitivity.

[Brief description of drawings]

FIG. 1 is a schematic view showing an embodiment of an abnormality detection device of the present invention.

FIG. 2 is a block diagram of the above embodiment.

[Explanation of symbols]

1, 10 ... Gears, 2, 11 ... Rotating shaft, 3 ... Oil film, 5 ... Annular body, 6 ... AE sensor, 7 ... Rolling bearing, 8 ... Housing, 25 ... Comparison circuit.

Claims (1)

[Claims] 1. An abnormality detecting device for detecting an abnormality of a rotary shaft or a mechanical element provided on the rotary shaft, comprising: a non-rotating annular body mounted on the outer periphery of the rotating shaft through an oil film; An abnormality detection device comprising an attached AE sensor.