A large corporation uses high volume powder metal bevel gears. The dies which are used during the powder metal manufacturing process are expensive and time consuming to produce. It is very advantageous, from a timing and a cost reduction standpoint, if design iterations of the dies can be reduced or even eliminated. The idea is to produce 3D models of the straight bevel gears and simulate the meshing of the gears in order to predict the tooth flank contact pattern of the gear set. Due to a strategic collaboration with a partner, we have obtained a software package which can perform the simulation of a virtual gear set.

In order to validate the gear set simulation, we used a straight bevel master gear set which had been produced for the corporation. The contact pattern for the master set was confirmed by running the set on a bevel gear tester at the specified mounting distances. The contact pattern obtained using the simulation software was compared to the observed contact pattern on the master gears. The contact patterns correlated. A final validation was achieved by inspecting the master bevel gear and master pinion using the 3D models for the tooth flank definitions. The resulting grid inspection results showed very minimal deviations using this approach.

The end result of this process is that the 3D models of both the pinion and the gear can now be employed by the corporation to create tool die designs which should produce gears which replicate the tooth form of the master gears. This means that theoretically, no design iterations will be required for the tools. The bevel pinons and bevel gears produced using the tools should have excellent tooth contact patterns. The design cycle for tool design and production has been significantly reduced.

Gas turbine engines are used in aircraft, industrial, and marine applications. These engines are designed to precision standards, and the engine hardware requires tight manufacturing tolerances. Validation of the units is performed in test cells specifically designed for the purpose. The cost per test hour is extremely expensive. The NAVY and Rolls-Royce Aerospace contracted Slone Gear to provide a test rig specifically intended for the evaluation of involute spline couplings. The idea was to be able to perform accelerated testing while maintaining close control over spline coupling alignment and loading. The cost of operating this spline test rig is far less than the cost of testing an actual gas turbine engine. In addition, the evaluation of the spline design can be accelerated so that the time required to validate a spline design is significantly reduced.

A unique spline test rig, based on a four square concept, was designed and manufactured by Slone Gear in conjunction with Schoolcraft Power Train. Essentially, spline test specimens, replicating the geometry of spline couplings in an engine, are produced and tested under high speed conditions at up to 10,000 RPM. Loading is achieved through the use of a hydraulic torque applier with “on the fly” adjustment capability. All of this means that mission profiles can be accurately simulated while accruing substantial savings of both time and dollars.