Belden Inc. supplies customized drive shaft assemblies for Mine-Resistant Ambush Protected (MRAP) multi-role military vehicles used in extreme environments.

According to the company's press release, Belden was contacted to supply a complete universal joint drive shaft assembly for a MRAP multi-role armoured vehicle. The drive shaft assembly connected the diesel engine and the compressor for the air conditioning unit the vehicle. The customer originally specified a standard 32mm OD needle bearing drive shaft with stainless steel yokes and a quick release hub feature for the initial testing two years ago.

In 2007, the entire vehicle was placed into a climate chamber to replicate the possible environmental elements the armoured vehicle could encounter in the various regions of the world. Belden says the tests proved to be extremely demanding on the universal joint drive shaft, resulting in premature failure.

Belden evaluated the application in the field and suspected that a combination of an undersized joint that could not handle the torque and rpm of the diesel engine, and the harsh temperature and operating environment inside the vehicle’s engine compartment contributed to the drive shaft failure. Another issue was the space limitations for a more robust joint. The distance was very short and a telescoping feature was mandatory for the assembly. The severe space constraints
limited the possible bearing size.

The redesigned drive shafts now include a larger, heavy duty bearing that is sealed and equipped with a lubricant that can handle a greater range of operating temperatures. The bearing seal can now better retain the lubrication during longer periods of extreme operation. The stainless steel yokes incorporate a custom profile and hub, and the quick release feature.

Belden needle bearing universal joints provide precise positioning and operate continuously at high speeds. The joint has rigid axial stiffness for push/pull loads. The needle bearing universal joint is
available in a wide variety of hub materials, including high grade alloy steel, various grades of stainless steel and an extruded aluminum for higher strength-to-weight ratios.