Shock Pulse Method , also known as SPM , is a patented technique for using signals from rotating rolling bearings as a basis for efficient monitoring of machine conditions. From the method innovation in 1969, it has now been further developed and expanded and is now a worldwide accepted philosophy for the monitoring of rolling bearing conditions and machine maintenance.
Video Shock Pulse Method
Difference between shock and vibration pulses
Consider a metal ball hitting a metal rod. In the event of a collision, pressure waves spread through the material of both objects (1). Waves are temporary (quickly muffle). When the front wave touches the shock pulse transducer, it will cause a muted oscillation of the transducer reference mass. Peak amplitude is a function of impact velocity (v).
During the next phase of the collision, the two bodies begin to vibrate (2). This vibration frequency is a mass function and a colliding body shape.
Maps Shock Pulse Method
Processing shock shocks
The shock pulse transducer reacts with large amplitude oscillations to the weak shock pulse, as it is vibrant at the resonant frequency of 32 kHz. Vibration machine, with a much lower frequency, filtered.
The first frame shows the symbol for the transducer and, below, the vibration signal from the machine, with the transient superimposed on the resonance frequency, caused by the shock pulse. The second frame shows the electrical filter passing through the transient train at 32 kHz. Their amplitude depends on the vibration energy of shock. Transients are converted into analog pulses. The last frame shows the shock pulse signal converted from the pad, now consisting of a fast sequence of stronger electric pulses.
Surprise pulse pattern
The filtered transducer signal reflects the pressure variations in the rolling bearing interface. When the oil film is in thick pads, the shock rate is low, with no distinctive peak. The rate increases when the oil film is reduced, but there is still no distinctive peak. Damage causes strong pulses at irregular intervals.
Measuring operating conditions
The Shock Pulse meter measures the shock signal on the decibel scale, at two levels. The micro processor evaluates the signal. Required input data defining the bearing type (ISO number) and speed of play (RPM and bearing diameter).
The surface damage on the pads causes a large increase in the strength of the shock pulses, combined with a noticeable change of characteristics between stronger and weaker pulses. The shock values ​​are thus immediately translated into relative oil film thickness measurements or surface damage, whichever is applicable.
See also
- Monitoring condition
- Vibration machining
- Spectrum analyzer
Further reading
Source of the article : Wikipedia
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