Machine Design

Scanning for Ideas: Machine Measures Bearing Torque

Bearing torque is defined as the torque needed to overcome both static and dynamic friction between a bearing’s inner and outer rings. And in these days of increased focus on energy efficiency, several bearing companies are offering products that tout low bearing torque. Until now, small and medium-sized manufacturers could not verify the ratings bearing companies gave their products because gages that accurately measure bearing torque were difficult to find. The Rotational Electromechanical Assembly Press from Promess Inc., Brighton, Mich. (, could change that. It can precisely control load and rotation while accurately measuring torque values, all while the bearing sits in an essentially frictionless fixture that eliminates fixture torque.

A multiaxis motion controller guides the press and tester. An air table with built-in torque sensing acts as a frictionless fixture. The table handles the high preloads needed for testing large-ball and roller bearings. And even at these high loads, the table’s friction is low enough to be negligible. All components are packaged in a compact workstation completely guarded by either a light curtain or sliding door.

The station handles miniature to large, heavy-duty, tapered bearings. Torque ranges go from 0 to 0.1 Nm to 0 to 50 Nm, and axial loads can be as high as 12,000 Nm. Accuracy is 1.5% of full range. The device can test bearings or determine the optimum preload for tapered roller bearings.

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