JPS61228119A - Acoustic emission detector in bearing - Google Patents

Abstract

PURPOSE:To obtain an acoustic emission (AE) detector of high reliability, by fixing one end of a wave guide bar to a drilled hole bottom surface and detecting AE being not damped from a bearing built inside a device. CONSTITUTION:A detector, adhesively attaching one end of a wave guide bar 10 while vertically providing it penetrating a through hole 8 drilled in a bearing case 6 and protruding the other end of the bar 10 from the bearing case 6, adhesively attaches an acoustic emission (AE) sensor 12 to a protrusive end part of the bar 10. The detector, filling a clearance between the wave guide bar 10 and an internal wall of a mounting recessed part 7 and the through hole 8 with resin 11, outputs an AE signal to the outside by a lead wire 3. Accordingly, the detector, detecting the AE signal before it is damped, improves reliability of the AE signal.

Description

[Detailed Description of the Invention] Industrial Field of Application This invention relates to acoustic emission (
Mu coustio Emission, hereinafter All! The present invention relates to an Alt detection device for predicting damage to bearings of tunnel excavators, aircraft, vehicles, ultra-low speed swing seats, generators, etc.

Conventional technology Conventionally, AI generated in a rotating body was processed using an aluminum alloy with a built-in piezoelectric element.
The following devices were detected by the 1f sensor.

(1) As disclosed in JP-A-52-15386, since AI[f is a high frequency, mercury has good sound conductivity in the high frequency band and does not stick to metal materials. Using the characteristics, as shown in Fig. 6, the rotating body a
1) IcA
! ! Sensor d is checked.

(2) If the inner ring of the bearing rotates, the AE sensor chi is installed in the outer ring, or if the outer ring rotates, it is embedded in a hole drilled on the surface or in the waist of the inner ring.

13) All
! One with a sensor attached.

Problems to be Solved by the Invention However, in the prior art (1) and (2) above, when incorporated inside a device like a bearing, the AIC is structurally difficult to solve.
Sometimes I couldn't attach the sensor.

Moreover, in the prior art (3), All! Since it is a high frequency and weak signal, it is attenuated greatly during the process of passing through the bearing box and the equipment body, making accurate detection difficult.

It is an object of the present invention to solve the above-mentioned problems of the prior art and to detect Ale from a bearing incorporated inside a device with less attenuation.

Means for Solving the Problems In order to achieve the above object, the present invention provides a method in which one end of a waveguide rod is fixed to the bottom of a hole bored in the non-rotating side raceway of a bearing or its support member. The present invention provides an Al1f detection device for a bearing, in which the gap between the waveguide rod and the hole is filled with a heat-resistant and insulating resin such as epoxy resin, and an AI sensor chip is fixed to the protruding end of the waveguide rod.

All! generated from the rolling part of the working bearing or its vicinity. is detected at one end of a waveguide fixed to the bottom of a hole drilled in the vicinity of the part, and is taken out as an electrical signal by a mucosensor fixed to the protruding end of the waveguide.

The heat-resistant and insulating resin such as epoxy resin filled in the gap between the waveguide rod and the hole insulates the waveguide rod and the inner wall of the hole, thereby preventing noise from the surroundings from entering the 5AI. prevent.

Embodiments Below, embodiments of the present invention will be explained based on FIGS. 1 and 2.

Embodiment 1 As shown in FIG. 1, this embodiment shows an example in which a tapered roller bearing is provided with an AI detection device. In a tapered roller bearing device in which a shaft 5 is fitted into an inner ring 2 of the bearing and a bearing box 6 is fitted onto an outer ring 1, electron wax ( A through hole 8 is made in the bearing box 6 and has a waveguide rod 10 with one end bonded to the bottom surface of the aluminum coated with an adhesive 9 that does not cause a damping effect. The other end is made to protrude from the bearing box 6, and the AI sensor chi 2 is glued to the protruding end, and the waveguide rod 10 and
The gap between the mounting recess 7 and the inner wall of the through hole 8 is filled with a heat-resistant and insulating resin 11 such as epoxy resin, and an Al signal is output to the outside via a lead wire 13.

Example 2 This example is an example of an AI detection device applied to a tapered roller bearing as in Example 1, and as shown in FIG.
0 mounting recesses 7 are provided in the bearing box 6.

Embodiment 3 This embodiment is an example of an AM detection device when a tapered roller bearing and a ball bearing are combined and installed in the device main body 17 as shown in FIG.
and the outer ring 1 of the ball bearing are respectively provided with mounting recesses 7 for waveguide rods 10, and the waveguide rods 10 are attached in the same manner as in the previous two examples, and the AIC signals output from each waveguide rod 10 are connected to the lead wires. 1
3 to the AI analysis device 15.

In each embodiment, in order to detect A11f without attenuating it, it is recommended to apply petroleum jelly, grease, etc. to the fitting and fixed parts in the bearing device, such as between the bearing box 6 and the outer ring 1, between the sleeve and the shaft 5, etc. It is valid.

According to the above-mentioned AI detection device, the tip of the waveguide rod 10 can be placed near the rolling part, so that the AI emitted from the rotating body has a high frequency band of 100KH2 or more and an intensity of 200μV. Even though it is a weak voltage of ~1mV, it is definitely A2+! can be detected.

Accurately detecting AI as described above is an effective means of accurately understanding the deterioration status of a bearing and estimating its remaining life. This can be confirmed by comparing the method of detecting the mechanical vibration or sound generated when such damage occurs and detecting that the bearing has already been damaged.

Figure 4 shows the vibration detected by the A8 detection device shown in Example 2 and the conventional acceleration vibration sensor for the same bearing in order to know the damage situation of the bearing during co-rotation. The effective value ←) is displayed so that the manner in which each changes over time of use of the bearing can be seen.

The vibration #effective value ←) does not generally change until the X mark point where damage such as peeling occurs on the surface of the rotating body, but Al! In ijl, a clear tendency of gradual increase is observed until reaching the X mark point.

This is because an acceleration sensor cannot detect even if a crack occurs internally until damage appears on the surface of the rotating body, but with an AI detection device, even if no damage appears on the surface, it cannot be detected. This is because if a crack occurs, Al produced when the crack occurs can be detected.

This crack is the internal crack that occurred in the bearing inner ring 2 shown in Figure 5 (0.13mm below the surface, 800 times) when AlC11 increases in Figure 4 (there is no change in the effective value of this special effect 1e7). This can be proven from the fact that it was discovered in

Therefore, the A11j detection device of the second embodiment prevents the AI generated inside the inner ring 2 from being attenuated by the waveguide rod 10 via the tapered rollers 3, the outer ring 11, and the bearing box 6.
It can be confirmed that the wave is guided to the sensor 12 and outputted from the sensor 12 as a highly reliable A11i signal, which also confirms that the A1 detection device in each example is highly reliable.

Effects of the Invention According to the present invention, one end of the waveguide is fixed to the bottom of the hole drilled in the non-rotating side bearing ring of the bearing or its support member, so that all of the waves can be removed from the bearing incorporated inside the device. It is possible to detect without attenuation and obtain a highly reliable AI multiplied signal.

Therefore, according to the above ARi, the signal! It is possible to accurately measure the amount of +AI, understand the deterioration status of the bearing during use, and estimate its remaining life.

[Brief explanation of the drawing]

FIG. 1 is a partially sectional side view of Embodiment 1 of the present invention;
Fig. 2 is a partially sectional side view of Example 2, Fig. 3 is a partially sectional side view of Embodiment 3, and Fig. 4 is the Alt measurement amount and vibration caused by the acceleration vibration sensor in Embodiment 2. Figure 5 is an enlarged view of an internal crack (0.131B below the surface, 800 times) that occurred in the inner ring during AID measurement in Example 2, and Figure 6 is a graph showing comparison with the effective value. ) is a front view showing the. 6... Bearing box - Support member 7... Mounting recess - Hole 9... Adhesive 10... Wave guide rod 11... Resin 12... ARI sensor

Claims (1)

[Claims] One end of the waveguide rod is fixed to the bottom of a hole drilled in the non-rotating bearing ring of the bearing or its support member, and a heat-resistant/insulating material such as epoxy resin is installed in the gap between the waveguide rod and the hole. Acoustic emission detection device for a bearing, which is filled with a transparent resin and has an acoustic emission sensor fixed to the protruding end of the waveguide rod.