Product category:
Seals
News Release from: Freudenberg Simrit LP | Subject: Simmerring seals
Edited by the Engineeringtalk Editorial
Team on 02 February 2007
Test exposes unreliability of look-alike
seals
A test carried out by Freudenberg Simrit demonstrates that manufacturers of driving engines and drive components are exposing themselves to huge risks by using imitation products.
Shaft seals are critical components in transmission systems, differentials and engines Leaks are not only a problem in themselves, they also damage the image of the machine or component manufacturer
According to the results of a test in which imitation seals were tested alongside original Simrit Simmerrings, manufacturers of driving engines and drive components are exposing themselves to huge risks by using imitation products.
Under normal test conditions, the imitation seal demonstrated serious crack formation, extensive abrasion and heightened groove formation after only 96 hours.
After the same period under the same conditions, the original Simmerring was as good as new.
The tribological system comprising shaft, lubricant, Simmerring radial shaft seal, and installation area is highly complex.
In order to ensure that the system functions faultlessly, it is essential that all these components are optimally adapted to suit each other.
This is the only way to ensure that the Simmerring acts like a microscopic pump that transports lubricants or gases into the joint gap and back into the oil chamber, thereby ensuring adequate lubrication between the shaft and the sealing ring.
Higher performances in drive technology mean higher speeds and, therefore, higher oil and joint gap temperatures.
However, the change in rotational direction, stop-and-go operation, high acceleration, undefined soiling, internal aggregate pressure, or different lubricants containing additives further increase the already complex demands made on the Simmerring.
This is why one of the most important targets when designing Simmerrings is to ensure that they fit perfectly into each tribological system.
Interdisciplinary teams of experts at Freudenberg Simrit work on this challenge in order to ensure that the company is in a position to offer optimised aggregate-specific solutions.
Neither the complex sealing material and sealing lip geometry designs nor the optimisation of the contact pressure force of the sealing lip on the shaft are visible to the naked eye.
It is exactly this that makes it easy for product pirates to manufacture cheap yet highly dangerous products.
The danger that lurks behind such imitation products becomes evident in a direct comparison of an imitation radial shaft seal and an original Simrit Simmerring.
The test parameters for this comparison were not very tough: both radial shaft seals were subjected to internal pressure of 0.3 bar and an oil sump temperature (in mineral oil) of 80C at a speed of 3,000U/min without interruption for a period of 24 hours.
Shaft misalignment and radial shaft deflection were 0.1 mm each.
Leakage, wear, and optical appearance of the sealing edge were compared for the purpose of analysis.
The results demonstrate just how quickly cheap imitations reach their limitations.
The width of the running track on the imitation seal was between 0.45 and 0.55mm.
The bearing area of the Simrit original, on the other hand, was between 0.20 and 0.25mm.
In terms of optical appearance, the imitation Simmerring demonstrated definite discolouration of the sealing edge.
After only 96 hours of test operation, cracks had formed on the imitation seal that would undoubtedly have resulted in leakage a short time later.
Moreover, there were clearly identifiable grooves in the track surface of the imitation seal.
This was not the case with the original Simmerring.
One particularly high risk was the clearly visible elastomer wear on the imitation seal after this short test.
The elastomer even began to flow in the joint gap!.
Even though the test was only brief, had operation continued, it would only have been a matter of time before the imitation radial shaft seal failed.
The original Simmerring, on the other hand, demonstrated absolutely no signs of abrasion.
Moreover, the track surface was still perfectly smooth at the end of the test.
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