The Cylinder Differential Tie Rod (CDT4) Series of NFPA hydraulic cylinders from Bosch Rexroth leverages technologies developed by company engineers for other products into a single application. They were able to combine these evolutionary features in a development lasting less than nine months, according to Market Applications Engineer Patrick Peters.

Project goal was long service life. One key to this longevity is a long, single-piece removable ductile iron (for reduced wear) bearing with tight tolerances. Reduced guide clearance allows more uniform load distribution, and a spiral groove in the rod bearing keeps the bearing lubricated and compensates for pressure change as well.

Another boost to reliability was to simply eliminate possible separation of the piston from the piston rod-instead of a press or interference fit, a pin stakes these mechanically together. The piston rod itself is chrome-plated to reduce its susceptibility to surface damage and to extend the life of the wear-resistant seals. Polyurethane seals are standard.

Other design features include integral air bleeds, and the optional Exact-a-just(TM) system with micrometer adjustment of softer cushioning stops to reduce internal and external shock. Pressure ranges up to 3,000 psi.

The CDT4 cylinders were designed for use in applications including machine tool, automotive, plastics machinery, material handling, and the wood and paper industry.