Direct contact
Harald Nitzschke +49 (0) 7303 - 92874 - 0 nitzschke@ttv-gmbh.de
In classic two-stroke engines, the crankshaft seal influences not only the sealing performance of the system but also the engine’s responsiveness and power delivery. Even minor friction losses or leakage can have a direct impact on overall performance. To unlock this potential, ttv developed a low-friction sealing solution specifically engineered for the aftermarket sector of the Simson Schwalbe.
As part of a development project for the Simson Schwalbe aftermarket, the optimisation of a crankshaft radial shaft seal was at the centre of attention.
The challenge was to reduce the seal’s friction losses as far as possible without compromising its sealing performance. Particularly in two-stroke engines, even the slightest leakage has a direct impact on crankcase pressure conditions, air-fuel mixture formation and, consequently, engine performance.
In addition, the seal had to permanently withstand the stresses caused by fluctuating pressure conditions, a fuel-oil mixture and elevated operating temperatures.
Harald Nitzschke, CEO ttv
The result is a crankshaft radial shaft seal that delivers exceptionally low friction while maintaining a high level of sealing stability. This reduces power losses and creates the conditions for optimum power delivery.
Custom-Engineered Solution with Proven Performance
In close cooperation between the VALVOtec sales team and the technical contacts at ttv, several prototypes were developed, tested and optimised. The results were convincing: while the conventional seal achieved an average of 20,000 brewing cycles, the custom-engineered solution from ttv withstands up to 40,000 cycles – doubling the service life and providing a clear competitive advantage for VALVOtec.
In addition to the geometry, both the material and the preload force were specifically tailored to the requirements of the two-stroke engine. A specially developed HNBR/FKM material combination was used, offering high resistance to fuel-oil mixtures as well as excellent thermal and dynamic load capacity. The spring force was precisely designed to achieve the optimum operating point between friction reduction and sealing reliability.
Focus on the Tribological System
Furthermore, the properties of the mating surface were taken into account with regard to surface roughness, runout and lead-free characteristics. After all, maximum performance is not achieved by the seal alone, but through the optimal interaction of all components within the tribological system.
Whether agricultural machinery, construction machinery, forestry technology, drive technology, mechanical engineering, automotive or aerospace, we are ready for your challenges. With our engineering solutions, we manage to offer added value in all decisive product parameters through solutions developed specifically for customers and applications. Get to know our competence and best examples in the most diverse markets.
