radial shaft seals
- June 03, 2020
Freudenberg Sealing Technologies has launched series production of a modular sealing unit that combines a classic radial shaft seal with a plastic outer case. The design promotes better long-term seal performance and longevity, is easier to assemble, and significantly lowers manufacturing costs in comparison with traditional metal-encased radial shaft seal units. Freudenberg has developed the innovative sealing concept for use in general industry applications that are especially focused on small, electric household appliances.
Whether it’s to knead bread dough, mix a cake batter, puree soup ingredients or blend a smoothie, most people reach for an electric kitchen appliance to get the job done. The durability of the appliance depends largely on how well the seal at the outlet point of the drive shaft protects the interior from ingress of food residue or liquids. Seals made of high-quality elastomers or the polymer polytetrafluoroethylene (PTFE) combine low wear with excellent long-term resistance against leakage. In the past, a metal case was the best option available to maintain the integrity of the seal’s performance over a long period of time. Freudenberg Sealing Technologies has now succeeded in developing a modular sealing concept with a plastic case that meets the specific requirements for long-term performance as well as those made of metal. There are three major advantages to the new design: Significantly, in the price-sensitive, small appliance industry, the lower production costs associated with forming enclosures from plastic is an important consideration. In addition, Freudenberg's modular sealing unit concept accommodates the integration of additional components, such as shaft bearings. Finally, because small appliance housings are typically made from plastic, fastening the seal case to the appliance housing is easier to achieve.
- April 17, 2018
Freudenberg Sealing Technologies has developed a new sealing system for Atlas Copco, the leading global producer of rock drills. The system has made it possible to double the maintenance intervals for a new generation of machines used in harsh underground conditions.
The drill bit strikes the surface of the stone with a force of 25 tons up to 140 times per second. Its task: to drill 80 holes where explosive charges are inserted. They blast away rock for supply tunnels for underground mining or for road construction. The drill bits are driven by rock drills. Two factors are decisive in keeping operating costs low: On one hand, the holes must be drilled very quickly, even in hard stone such as granite, which requires very powerful forces. On the other hand, despite the strong forces, maintenance intervals are supposed to increase. With the development of its new machine, the COP MD20, Atlas Copco has resolved its conflicting objectives: Without a reduction in the machinery’s rate of advance, the company was able to double its maintenance intervals.
A new sealing system from Freudenberg Sealing Technologies was the key component in accomplishing this, as the metallic components, especially the piston that drives the drill bit, had been previously optimized by using special high-strength alloys. But the forces that are produced, especially during the bit’s recoil, are so high that they severely stress the seals in this high-pressure hydraulic system. If the seals develop wear, the result can be leakage, which has a highly negative effect on the relationship between the applied energy and the boring power – in other words, the system efficiency declines.
©Atlas Copco Rock Drills AB