Custom-designed precision plastic bearing resolves distortion and disassembly problems, while increasing load-bearing capabilities for a mobile satellite antenna.

When the world’s leading provider of mobile satellite communications and TV-based antennas, KVH Industries Inc., began to experience problems with its bearing failing to meet the high standards demanded by the product, it commissioned BNL to find a solution.

KVH’s original bearing was distorting and disassembling during operation, pushing apart under very low loads. It was also complex to manufacture, and the high cost of the machining process was unsatisfactory. The brief to BNL was to resolve these problems quickly.

At 242 mm in diameter, the bearing is BNL’s largest regularly manufactured part. It is used in two of KVH’s sophisticated satellite TV antenna systems: the TracVision L2 land mobile antenna and the TracVision G6 marine antenna. Such sensitive, state-of-the-art equipment demands a precision bearing that can move accurately to maintain a consistent and uninterrupted satellite signal as the vehicle moves.

The BNL solution is an azimuth bearing injection-moulded from acetal with stainless-steel balls. It offers significant improvements over the original bearing’s performance. The redesigned raceways increased the push-apart force by 300 times, preventing disassembly during operation. BNL’s tooling strategy also minimised machining operations, reducing the cost per part by more than 25%. The team was also able to integrate additional features, including pads that provide greater stability for the finished product.

“One of the challenging aspects of this bearing was manufacturing thin-section parts with tight tolerances across large dimensions, while allowing free running and stability,” explains BNL R&D Manager Jason Gregory.

“The development undertaken at BNL enabled us to add a planar deflection to the races of 3 mm, peak to peak, with little increase in rotational inertia. This meant we could be confident that the parts could be attached to a non-flat surface without unduly affecting the bearing’s capabilities.”