Detection of the characteristics of 7.2 torsion springs

When measuring torque, the size of the torsional spring axis must be suitable. The inner diameter of the spring should be kept to a certain gap, and the friction force and friction torque caused by the contraction of the inner diameter of the spring should be avoided, and the measurement accuracy should be affected. But the spindle can not be too small, otherwise it will cause the offset between the external torque and the measuring torque center, resulting in the error of the torque measurement. The specific testing program for torsion spring torque: in addition to the pattern, the spring twists the spring to three times of the torsion angle corresponding to the allowable bending stress; the spring is worn in the test bar, the diameter of the core bar is slightly less than the inner diameter of the spring, and when the spring is twisted to the specified angle, it does not bite the bar phenomenon, and when necessary, the heart rod is necessary. The surface can be coated with lubricating oil to reduce the friction force of the inner diameter of the spring and the rod of the heart; fix the torsion arm and turn the hand wheel of the spring torque test machine to make contact with the other torsion arm. At this time, the reading number of the torque tester T. 0.05T; record To, angle the zero position, continue to turn the hand wheel to make the twist angle change to the specified value; gently knock. The spring reduces the friction force between the inner arm and the heart bar of the spring to a minimum, and records the torque test machine's display value T; the spring torque is T=T- To.

7. Tests on Standing and Permanent Deformation of Cylindrical Helical Springs

Standing is the basic requirement for springs, and the finished springs must be fixed so that the springs will not work.

Permanent deformation will affect the performance and normal work of mechanical equipment or components. test

The method of spring setting is to check the residual deformation of springs, which usually compress the compression springs.

 Or load the tensile springs and torsional springs to the test loads or the loads specified in the drawings.

Repeated loading and unloading after three times. The permanence of an unsettled spring after loading

The long deformation (residual deformation) is the largest in the first time, and then decreases gradually to several times later.

Its geometric dimensions remain unchanged.

The tensile spring with initial tension is maintained after the standing test.

Invariable, but the initial strain decreases gradually, and the corresponding initial deformation decreases.

The change of initial deformation is not reflected in the free length, so the test method is not.

Measure the length, but measure the load.