Abstract：A set of high accuracy 1mN·m～1N·m torque standard machine was newly developed at National Institute of Metrology (NIM). A static air bearing is used to support an arm lever at a fulcrum, a single beam structure is adopted in the arm lever which is equipped with a balancing beam and a overload protection part, an unique weight loading system is designed and manufactured by using precise combination of load frame, groups of weights and weight supporting part. The working principle and mechanical structure of the machine are introduced, the results of performance test and uncertainty assessment are described. The theoretical analysis and performance tests show the expanded uncertainty(k=2) of the machine is less than 3.4×10-4 from 1mN·m to 5mN·m, 7.4×10-5 from 5mN·m to 100mN·m, 2.6×10-5 from 100mN·m to 1N·m.
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2018, Vol. 39 
