Measuring rolling bearing forces. Monitoring lubrication.

Bearing damage: Identify causes early & avoid bearing failure

Bearing damage can have many causes. Misalignment, imbalance, vibration and friction are transmitted by the bearing and can lead to bearing breakdown.

As a centerpiece of any plant, the bearing is one of the most important machine components. Bearing damage and thus machine failure can lead to costly downtime, damage to neighboring parts and considerable repair costs.

Damage to rolling or plain bearings is often a long-term affair. Even if no consequential damage has occurred and replacements are in stock, a multi-hour repair usually has to be scheduled depending on the complexity of the machine and the installation location. In the worst case, however, consequential damage has already occurred. In this case the repair will be correspondingly expensive and time-consuming.

It therefore makes sense to keep a permanent eye on the condition of your machine. This means identifying bearing damage at an early stage and becoming aware of its causes. This article is intended to support you in this regard.  

 

Table of Contents: An overview of bearing damage, its causes and symptoms.

What are the typical causes of bearing damage?

A large percentage of all premature bearing failures are preventable. According to in-depth research, the causes of all bearing failures and their frequency can be divided into four groups:

Ausfallursachen für Wälzlager (Quelle: Antriebstechnik 18 (1979) Nr. 3, 71-74).

 

  1. Poor lubrication (ca. 55%)
  2. Environmental effects and soiling
  3. Installation und Montagefehler (ca. 10%)
  4. Overload or fatigue under operational load (ca. 10%)

In practice, various external factors usually act in combination. In many cases, several damage characteristics will also be observed simultaneously on a bearing. In this case, it is often difficult to determine the primary cause of failure.

How do you recognize symptoms of bearing damage at an early stage?

Bearing damage usually manifests itself by deteriorating operating behavior over time. Depending on the operating conditions a few minutes or even months may pass between the start of the damage and the actual bearing breakdown.

In some applications of rolling bearings it is sufficient to prevent major damage if the operating personnel pay attention to unsmooth running or unusual noises of the bearing and check the temperature of the bearing and lubricant continously. Conspicuous lubricant samples e.g. with increased metal proportion or strong discoloration of the lubricant can be an indication of bearing damage.

In many applications, however, these symptoms appear at such a late stage that there is no sufficient warning time before damage occurs. It is therefore advisable to use additional technical systems that detect damage before it becomes apparent to the operating personnel. If you would like to learn more about technical prevention systems, take a look at Chapter 4: Preventing bearing damage early of this article. 

Which causes can be hidden behind the symptoms?

 

An excessive bearing temperature is an indication of increased friction. A significant increase
in temperature occurs with all bearing damage as soon as it has been progressed and can therefore be an indication of imminent machine failure. 

Slight temperature deviations can be caused by too little or too much lubricant being used. An increased load on the bearing or installation errors such as a too tight fit or preload can also lead to temperature increases in the bearing.

Causes and symptoms of bearing damage (Source: Schadenserkennung und Begutachtung gelaufener Wälzlager, FAG, 12-13).

An increased noise development is also a clear indication of bearing damage. By analyzing the frequencies, the cause of the damage can be narrowed down more precisely. In most cases, such damage is caused by insufficient lubrication due to an oil level that is too low or due to an unsuitable lubricant. Overloading of the bearing and installation errors are also frequent causes of damage.

An unsmooth running is often manifested by increasing vibration or fluttering during operation. Running irregularities are often caused by oscillating operating stresses or can be caused by contamination with dust and dirt, but also by liquid contaminants such as water or acids. 

How can bearing damage be prevented before it occurs? And how can HCP Sense GmbH assist here?
Smartes Lager mit Auswerteelektronik und App Anwendung

HCP Sense offers a unique, simple and economical measurement technology for monitoring loads and lubricant conditions in rolling bearings.

The loads applied in a machine contain highly relevant information about the stress on the machinery. Measuring these loads therefore offers great potential in terms of Predictive maintenance or condition monitoring .

With regard to the prevention of bearing damage, overloads, for example caused by assembly errors, can be detected immediately.

By measuring the load , it is also possible to calculate the remaining service life of the bearings and other components, e.g. shafts and gear teeth, in real time. This means that maintenance can be carried out precisely just before the calculated end of service life. Accordingly maintenance intervals can be extended and unplanned downtimes are minimized.

In addition, our sensor bearing can monitor the lubrication and thus eliminate the main cause of bearing damage. On the one hand, the lubricant quantity can be kept in the optimal range, and on the other hand, the general condition of the lubricant is monitored. This makes it possible to move away from rigid maintenance intervals to needs-based predictive maintenance.

HCP Sense uses modified standard rolling bearings that occupy the same space as conventional bearings. Our product is therefore very easy to integrate even into your existing machinery.

Give us a call, we will be happy to advise you!

You can find more information about our condition monitoring services under the tab Products.

Simply call us +49 172 1805442 if you would like to speak to Dr. Tobias Schirra our expert in rolling bearing technology.

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