Material

ZX-324

Description of the application

In the construction industry, the loading area of a tipper truck is loaded up to 30 tons of bulk material or  bitumen with temperatures up to max. 250°C. The loading platform is supported via a spherical cap of a the hydraulic cylinder. The cap is positively fi t in the calotte at the end of the hydraulic cylinder and allows the  tipping on three sides.

Load

300 kN with a temperature of the spherical cap of 250 °C (through hot bitumen) or also at temperatures  below the freezing point. At these conditions, impacts and vibrations, caused by the loose contact of the truck loading platform, occur during the drive on unevenness ways. In both cases, the aforementioned load is  overlapped from a relative movement between the ball and cap when lifting and lowering the platform.

Problem

Since that bearing seat is of diffi cult access, high maintenance costs for the re-lubrication incurred. Also for environmental reasons, a maintenance-free-in-dryrunning-conditions bearing was requested.

Problem-solving

A spherical cap with a calotte diameter of 60 mm made of ZX-324 is used. The spherical surface is 6.300 mm².

Working life

10 years as requested. Working life in the test stand: afterwards 50.000 load cycles, which corresponds to approximately 13 years, the bearing was still fully functional.

Advantages

A cost reduction by dry running and maintenance-free has been archived, and therefore the lubricant  environmental impact has been reduced.