CN100399003C - Laser Measurement Method of Vibration Displacement of Rolling Bearing - Google Patents

Abstract

The invention discloses a laser measuring method for the vibration displacement of a rolling bearing. Install the tested bearing on the rotating shaft of the test bench, and use the laser to reflect on the surface of the PSD sensor through the bearing surface, and the position of the light spot is given by the PSD position sensor. Due to the axial force on the outer ring of the bearing, the inner ring of the bearing and the main shaft It can be regarded as a rigid body. When the rotating shaft rotates, the defects of the inner ring, outer ring and rolling elements of the bearing cause vibration. The position change of the reflected laser on the PSD position sensor reflects the displacement s of a certain point on the bearing surface under test. . The invention has simple mechanism, clear principle, better vibration picking effect than other types of vibration tests, high precision, and almost negligible influence on the vibration of the bearing system itself. It has practical value and great economic development prospects for further improving the measurement accuracy and application stability of bearing vibration, and is suitable for vibration measurement of any reflective surface, such as the vibration situation of the surface of a motor vehicle.

Description

Laser Measurement Method of Vibration Displacement of Rolling Bearing

technical field

The invention relates to mechanical vibration measurement, in particular to a laser measurement method for vibration displacement of a rolling bearing.

Background technique

Bearing vibration measurement generally has two types of measurement methods: velocity type and acceleration type. The principle is to use magnetic velocity measurement sensor and piezoelectric crystal acceleration sensor respectively. But in any case, it is necessary for the vibration pickup to be in contact with the outer surface of the bearing, and to maintain a certain degree of combination, that is, a certain rigidity, so as to improve the frequency response of the system. The existing problems are: the frequency response of the mechanical vibration pickup cannot be too high, and the contact installation method of the sensor also causes the instability of the measurement system. In order to improve the shortcoming of the low frequency response of the system, a magnetic suction clamping method of the sensor has appeared, but the system is complex, inconvenient to disassemble and assemble, and the application is more difficult, and a demagnetization process needs to be added.

Contents of the invention

Therefore, the object of the present invention is to provide a non-contact laser measurement method for the vibration displacement of rolling bearings, which overcomes the deficiencies in the prior art.

The technical solution adopted in the present invention is: install the tested bearing on the rotating shaft of the test bench, and use the laser light emitted by the laser to reflect on the surface of the tested bearing to reach the surface of the PSD position sensor, and the PSD position sensor gives the spot position. Under the action of the axial force on the outer ring of the bearing, the inner ring of the tested bearing and the rotating shaft can be regarded as a rigid body. When the rotating shaft rotates, the defects existing in the inner ring, outer ring and rolling body of the bearing cause vibration. The position change on the sensor reflects the vibration displacement s of a certain point on the bearing surface under test.

Adjust the incident angle θ/2 of the laser and the incident angle π/2-β of the PSD position sensor) so that the incident angle θ/2 of the laser on the surface of the bearing to be tested is within 15°. Angle of incidence β, so that the receiving laser range is within the measurement range of the PSD position sensor.

The displacement s of the vibration is:

以初始位移为0点，s：轴承测量点位移，θ：两倍激光入射角，β：π/2-β-PSD位置传感器的入射角，S：PSD位置传感器的测量位移；测量后取位移s的有效值作为测量评判指标。

Take the initial displacement as 0 point, s: the displacement of the bearing measurement point, θ: twice the incident angle of the laser, β: the incident angle of the π/2-β-PSD position sensor, S: the measured displacement of the PSD position sensor; take the displacement after measurement The effective value of s is used as the measurement evaluation index.

The beneficial effects that the present invention has are:

1. Avoid the unstable phenomenon in the contact-type clamping method, that is, the stiffness of the vibration pickup is unstable; the non-contact measurement method is relatively simple, easy to use, and easy to guarantee accuracy. In addition to general laboratory measurements, it is also It can be applied to the quality control and online detection of the bearing production site;

2. The basis of the method of unifying the velocity measurement and acceleration measurement of the vibration of the bearing under test, that is, the displacement measurement; the primary difference and the secondary difference (or differential, an analog circuit can be used to increase the speed) of the displacement versus time will be Obtain the velocity value and acceleration value of the vibration respectively.

3. The frequency response of the system can reach a very high level (above 2MHz), and the measurement range can almost cover the vibration of all frequencies of the bearing (at the speed specified by the bearing measurement standard).

4. After the measurement, take the effective value of the displacement s as the measurement evaluation index.

The invention is not only applicable to the bearing vibration industry, but also applicable to the detection of the vibration of any reflective surface, such as the vibration of the surface of an engine or a motor vehicle.

Description of drawings

Fig. 1 is the laser method measurement radial bearing vibration schematic diagram of the present invention;

Fig. 2 is a schematic diagram of measurement calculation in the bearing vibration laser measurement method of the present invention.

In the figure: 1. laser device, 2. rotating shaft, 3. radial bearing, 4. thrust device, 5. PSD position sensor.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

Taking advantage of the small divergence angle of the reflected laser, a PSD position sensor is placed at the end of the reflected laser to measure the tiny displacement during the vibration process. Since the measurement sampling frequency is much higher than the maximum vibration frequency of the bearing measurement, the maximum vibration frequency is given by the measurement standard, so the measurement results can reflect the amplitude and frequency of the bearing vibration.

As shown in Fig. 1 and Fig. 2, the present invention installs the tested bearing 3 on the rotating shaft 2 of the test bench (such as the s0910 type bearing vibration measurement test bench), and the thrust device 4 is loaded from the end face of the tested bearing 3, so that the tested There is no gap between the outer ring and the rolling elements, as well as the inner ring and the rolling elements of the radial bearing 3, in order to reflect the vibration caused by the machining accuracy of the bearing. The reflection reaches the PSD position sensor 5, and the spot position is given by the PSD position sensor 5. Due to the axial force on the outer ring of the bearing under test, the inner ring of the bearing under test and the rotating shaft 2 can be regarded as a rigid body. When the rotating shaft 2 rotates , the defects of the inner ring, outer ring and rolling body of the bearing under test cause vibration, and the position change of the reflected laser on the PSD position sensor 5 reflects the displacement s of a certain point on the surface of the bearing under test 3 .

Adjust the incident angle θ/2 of the laser 1 and the incident angle π/2-β of the PSD position sensor 5, so that the incident angle θ/2 of the laser on the surface of the bearing to be tested is within 15°. By adjusting the received laser to the PSD position sensor 5 The incident angle β of the surface makes the range of receiving laser light within the measurement range of the PSD position sensor 5 .

The displacement s of the vibration is:

以初始位移为0点，s：轴承测量点位移，θ：两倍激光入射角，β：π/2-β-PSD位置传感器的入射角，S：PSD位置传感器的测量位移；测量后取位移s的有效值作为测量评判指标。

Take the initial displacement as 0 point, s: the displacement of the bearing measurement point, θ: twice the incident angle of the laser, β: the incident angle of the π/2-β-PSD position sensor, S: the measured displacement of the PSD position sensor; take the displacement after measurement The effective value of s is used as the measurement evaluation index.

It can be seen from Figure 1 that this measurement method realizes non-contact vibration pickup, and the system response frequency only depends on the response frequency of the sensor and the processing speed of the signal system.

As shown in Figure 2, when the position of the bearing 2 to be tested changes, the position of the surface irradiated by the emitted laser light of the laser 1 will also change, so the incident angle needs to be as small as possible, so as to be able to approximate a certain A point of measurement. As shown in Figure 2, the incident angle is θ/2, and the incident angle of the reflected laser light on the photosensitive surface of the PSD position sensor is π/2-β. If the accuracy is not enough, it can be improved by reducing β. In the case where the displacement of the PSD sensor is S, the displacement s of the light spot on the surface of the tested bearing can be obtained as:

s=S[cos(β-θ)+tg(β-θ)tg ^-1 (θ)]

It can be seen from the above formula that as long as it is within a certain measurement range, that is, the vibration situation near a point can be completely and uniquely determined. And the vibration of its velocity and acceleration can be obtained from its displacement.

The measurement sampling frequency should be more than 8 times of the highest vibration frequency, and more than 20 times for formal use, which can ensure the stability of the measurement data. The effective laser spot diameter on the PSD position sensor shall not exceed 15% of the measuring range of the PSD position sensor.

The invention is not only applicable to the vibration of the bearing, but also applicable to the measurement of the micro vibration of the surface, such as the vibration of the surface of the engine or the motor vehicle.

The specific embodiments above are used to explain the present invention, rather than to limit the present invention. Within the spirit of the utility model and the protection scope of the claims, any modification and change made to the present invention will fall into the protection scope of the present invention.

Claims (2)

1. the laser measurement method of a vibration displacement of rolling bearing, it is characterized in that: measured bearing (3) is installed in the rotating shaft (2) of testing table, the laser that utilizes laser instrument (1) to send arrives on PSD position transducer (5) surface through measured bearing (3) surface reflection, provide facula position by PSD position transducer (5), because the effect of the suffered axial force in measured bearing outer ring, measured bearing inner ring and rotating shaft (2) can be considered a rigid body, when rotating shaft (2) is rotated, bearing inner race, the defective that outer ring and rolling body exist causes vibration, utilize the change in location of reflector laser on PSD position transducer (5), reflect certain displacement s that a bit vibrates of measured bearing (3) surface; Adjust incident angle θ/2 of laser instrument (1) and the incident angle pi/2-β of PSD position transducer (5), make laser to incident angle θ/2 on measured bearing surface in 15 °, accept in the measurement range that lasers range is in PSD position transducer (5) by adjust receiving the incident angle β of laser, making PSD position transducer (5) surface.

2. the laser measurement method of a kind of vibration displacement of rolling bearing according to claim 1, it is characterized in that: the displacement s of described vibration is:

With initial displacement is 0 point, s: the displacement of bearing measuring point, θ: twice laser incident angle, the incident angle of β: pi/2-β-PSD position transducer, the Displacement Measurement of S:PSD position transducer; Fetch bit moves the effective value of s as measuring judging quota after measuring.

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