Spotlight on – Gear insepection machine needs of large crane manufacturer


Challenge Liebherr Werk Bieberach, GmbH is a German manufacturer of large construction cranes. Their needs are unique to say the least. The sheer size of the cranes means gear measuring machines for gears and bearings that may be as big as 20 feet. This is not an off the shelf CMM, this requires innovative thinking and expert custom engineering and manufacturing.

SOLUTION WENZEL designed and built a special gear measuring machine that combined their standard components and proven dual-arm measuring technology with the precision air bearing mechanics of the WENZEL WGT series of Gear Checkers.  The inspection machine is capable of inspecting bearings and ring gears up to 6000mm (19.68 ft) diameter.

large gear

The dual-arm machine design is similar to what WENZEL has applied in the automotive industry to measure car bodies and body components. In this design, the CMM measuring arms are each mounted to a table that is mounted on a large corresponding granite base. The gear inspection machine arms feature high-accuracy linear guideways for the X-axis. The Y- and Z-axes feature finely tuned, preloaded roller bearings providing minimum friction and operational wear.

The base units are positioned opposite each other with a rotary fixture table in between. Both arms measure the large rings concurrently and the metrology of each measuring arm is harmonized through the use of a specially designed calibration tool. The ring gears and bearings are located and clamped on the 2200 mm (7.21 ft) diameter hydrostatic rotary table that can handle loads up to 100,000 lbs.

gear inspection machine

The complete circumferences of the rings are inspected by a single inspection part program. Application software is also provided that can calculate the optimum fitting tolerance for inner and outer bearing components.

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