Definition
A torque tester is a measuring device used to measure and calibrate rotational torque. It simulates the torque application and measurement process in actual working conditions to achieve accurate transmission and verification of various torque tools and sensors, and is a key device to ensure the accuracy and unity of torque measurements.
How it works:
The core working principle of the torque tester is based on Hooke's law and the principle of lever balance. When the measured torque acts on the sensing component of the instrument, it will cause the deformation of the elastomer, which is converted into a resistance change by the strain gauge, and then processed by the circuit to output an electrical signal proportional to the torque. Its basic relationship can be expressed as:
M = k × θ
where M is the torque value, k is the torsional stiffness coefficient of the system, and θ is the torsional angle. The instrument determines the correspondence between the input torque and the output signal through calibration, so as to achieve quantitative measurement.
Measurement method
Torque calibrator measurements usually follow static or quasi-static methods. In static measurement, the standard torque is applied to the input of the instrument in turn, and the output value is recorded, and the error of the value is obtained through comparison. Dynamic measurement simulates the continuous loading process in actual use to evaluate the response characteristics of the instrument. The measurement process should be in accordance with national metrology verification regulations or international standards, such as JJG 797, ISO 6789, etc., to ensure the traceability of the measurement chain.
Influencing factors
The accuracy of the measurement results is influenced by several factors. Changes in ambient temperature may change the elastic modulus of the sensor material; Humidity can affect the stability of electrical connections. Mechanical factors include installation coaxiality, bearing friction, lateral force interference, etc. Operational factors such as loading speed, holding time, and number of repeated loads also introduce measurement uncertainty. In addition, the long-term stability of the instrument, zero drift, and overload history need to be taken into account in the validation.
Applications:
Torque testers are widely used in industrial links that require strict control and verification of rotational torque. In automotive manufacturing, tightening tools used to calibrate engine assembly lines; In the aerospace field, it is used to ensure that the preload of the connecting bolts of structural parts meets the design requirements; In electronics assembly, ensure that the tightening moment of precision screws is within a safe range. At the same time, it is also the basic equipment for torque measurement value transmission and instrument verification by measurement institutions, laboratories and quality departments.
Key points of selection
When choosing a torque tester, it is necessary to comprehensively consider the measurement range, accuracy level, interface form and functional requirements. The measurement range should cover the minimum and maximum torque of the tool under inspection, with an appropriate margin. The accuracy level should usually be more than three times higher than that of the instrument being tested. The interface needs to match the drive head or fixture of the tool being inspected. In terms of function, it is necessary to weigh the portability, automation, data recording ability and environmental adaptability of the instrument according to whether it is used for on-site rapid verification or laboratory precision verification. In addition, the calibration cycle, maintenance costs, and technical support of the instrument are also factors that need to be evaluated in long-term use.