Water pump seals reduce vibration in cars and trucks

Dean Palmer investigates a new mechanical face seal for water pumps that reduces axial, radial and tangential vibration in passenger cars and trucks A new range of mechanical face seals has been developed that reduces axial, radial and tangential vibration in water pumps driven by tooth wheels and chains used on passenger cars and trucks. Freudenberg Simrit's new CS850 seal is surrounded by an elastomer component in such a way that all vibrations components are perfectly damped. Together with elastomer components that largely isolate sliding rings from vibrations, the highly wear resistant SiC/SiC material combination that makes up the sliding ring forms the basis for this mechanical face seal with integrated vibrational compensation. The axial vibration components are also minimised by modifying the spring contact pressure. In conjunction with renowned spring manufacturers, an optimal design for spring contact pressure and spring force transmission to nearby sealing components has been achieved and verified on test rigs in endurance tests. To improve torque synchronisation, an elastomer-supported hexagon carrier was developed with optimised contact surfaces, ensuring reliable torque transmission even under critical vibration loads and to reduce radial vibration components to a minimum. Since the high level of vibrations makes it unusually difficult to transfer torque to the mechanical face seal, the seal is made extremely wear-resistant by means of a CVD coating. There are other advantages too. The novel seal design prevents operating damage even when pressure peaks occur and its open construction supports heat dissipation, making it suitable for the high demands placed on water pumps in trucks and cars. The seal also withstands coolants with a high percentage of particles.