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Gear Box Common Fault Performance And Diagnostic Measures

Jun 23, 2017

Gear Box is an industrial component, it can pass the transmission gear system to complete the power transfer task, at the same time, Gear Box as a transmission gear of mechanical parts, the use of chemical is also very wide. In this paper, the application of the gear box, the gear box of the common fault performance and diagnostic measures in detail.

First, the use of gear box

The main purpose of the Gear Box is as follows: First, it can change the speed of transmission through the gear set, often in the industry called "variable speed gear box." Second, the Gear Box can change the rotational torque, that is, under the premise of the same power, the greater the speed of the gear, the gear shaft by the torque but the smaller, in turn, the greater the gear box for the power Distribution, in the industry, the staff can use an engine, through the spindle of the gear box to affect a number of from the shaft, and then as long as an engine will be traction several loads; Fourth, the gear box has a clutch function, the brake clutch is used Gear Box clutch function, people are free to separate the two intermeshing gear separated, and then the load and the engine split; Fifth, change the direction of transmission, may wish to use two fan-shaped gear to the force in which the vertical The direction of the orderly conduction to the other side of the rotation axis.

Second, the typical performance of the Gear Box failure failure

Through the analysis of the practical application of the gear box, it is not difficult to determine the fault. The entire Gear Box system consists of components such as bearings, gears, drive shafts and box structures. As a commonly used mechanical power system, it is very prone to mechanical parts failure, especially bearings, gears and drives Shaft of the three parts, the probability of other failures are significantly lower than they are.

When the gear performs a task, the lack of work due to various complex factors, the value of the functional parameter goes beyond the maximum critical value allowed, which results in a typical Gear Box failure. The first is the gear in the cumulative rotation of the gradual generation, because the outer surface of the gear box in the process of carrying out a relatively large load, the meshing of the gears of the gears The gap will appear relative to the rolling force and sliding force, sliding friction and poles at both ends of the direction of the opposite, over time, long-term mechanical operation will make the gear gluing, cracks, increase the degree of wear and tear, It must be. Another type of failure is due to the staff is not familiar with the safe operation process or violate the operating specifications and requirements, in the installation of gears in the event of negligence, or in the initial manufacturing for the occurrence of the fault buried a hidden trouble, this failure is often because The inner hole and the outer ring of the gear are not the same as the center of the circle, the gears interact with each other when the shape of the error and the axis distribution asymmetry.

In addition, in each of the Gear Box components, the shaft will also be prone to a part of the flash, when there is a relatively large load impact shaft, the shaft will quickly deformation, direct induction of the gear box of the fault The When the fault diagnosis of the gear box, the deformation of the axis of the shaft for the impact of the failure of the gear box is inconsistent, of course, there will be a different fault performance, so that the distortion of the shaft there are heavy and mild The Shaft imbalance can cause failure, for the following reasons: work in a large load environment, over time is also inevitable; the shaft itself in the production, manufacture and processing and many other processes exposed a series of defects, resulting in the new cast The shaft will show a serious imbalance.

Third, the gear box fault diagnosis strategy

Gear box is a uniform gear and gear bearing a unified body, due to processing defects or under pressure caused by all kinds of failures are worthy of attention, in general, usually the following methods:

1. Crosstalk analysis approach

Cepstrum analysis, also known as secondary spectrum analysis, is a new technology in modern signal processing science. When the spectrum of the mechanical signal appears difficult to identify the multi-family modulation frequency, the cepstrum can decompose and identify the fault frequency, analyze and diagnose the cause of the fault.

In the case of a vibration spectrum of a Gear Box with a plurality of pairs of gears, the side bands occur when each pair of gears is engaged. When the individual side bands are arranged in an intertwined distribution, only the identification analysis of the frequency refinement is far Not enough, because the cepstrum spectrum of power will be converted into a harmonic spectrum within the spectrum of a single line, its location also implies that the power spectrum in the corresponding harmonic frequency interval.

Another significant advantage of the cepstrum is that it is insensitive to the signal transmission path of the sensor or the orientation of the measuring point, which is insensitive to the correlation between the frequency regulation and the amplitude of the amplitude, which in turn helps to monitor the size of the fault signal Measure the specific value of the amplitude of a measure.

2. Edge band analysis method

In the usual sense, the edge band is analyzed from two aspects, one is the range of variation of the amplitude of the sideband in each measurement process. There is also a symmetrical characteristic of the frequency band of the side band to see the specific frequency relationship. The frequency band of the modulation signal and the frequency of the meshing of the Gear Box.

It should be noted that the gears fall off, the root of the root of the cracks and individual broken teeth and other individual failures will appear obvious transient modulation in the meshing position and its sides will have a series of sidebands, their characteristics are mainly Order more dense, scattered lines. The shape of the frequency is different due to the cascading between the higher order frequencies. If there is a significant local fault can also promote the harmonic components and the frequency of rotation.

Here the sideband component contains a sufficient Gear Box fault information resources, in order to obtain this information, in the spectrum analysis need to have sufficient frequency resolution, and thus promote the edge band distance can be accurately measured.

3. Power spectrum analysis approach

The power spectrum is the statistical average of the stochastic process, and the power spectrum of the stationary stochastic process is a definite function. This method can determine the frequency structure of the vibration signal of the Gear Box and the distribution of the vibration energy at each frequency. Since the power spectrum and the amplitude value form a square relationship, the power spectrum will be more prominent than the amplitude spectrum Wave of the line spectrum components and the frequency of engagement, reducing the vibration signal caused by a series of "burr" phenomenon.

Fourth, the conclusion

Gear Box in addition to the chemical industry in a wide range of applications, the same applies to other areas. In the event of failure after failure, can not rush to take too many means and measures to be corrected, but the first analysis of the root causes of failure, appear in which part, identify security risks, select the most appropriate strategy to proceed with disposal and diagnosis Get a multiplier effect.