A dynamic test method for stress relaxation of torsion springs

A technique for stress relaxation, dynamic testing

Active Publication Date: 2021-08-20
INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] The purpose of the present invention is to provide a dynamic testing method for stress relaxation of torsion springs, which adopts a cyclic load loading method, simulates the actual working conditions of torsion springs and includes several fretting cycles, and solves the problem of large deviations in current torsion spring stress testing methods

Method used

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  • A dynamic test method for stress relaxation of torsion springs
  • A dynamic test method for stress relaxation of torsion springs
  • A dynamic test method for stress relaxation of torsion springs

Examples

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Embodiment 1

[0049] In this embodiment, the actual working condition parameters of the torsion spring are shown in Table 1 below, and the torsion spring has completed 20,000 working cycle stress relaxation tests, and the working cycle curve of each cycle is shown in figure 1 , from Table 1 and figure 1 It can be seen that the actual working condition of the torsion spring is: first load the torsion spring to the minimum torsion angle of 97°→vibrate 7 times near (97°±15°), and finally stop at 97°→continue to load the torsion spring to 143°, and there are (143±10)°vibrations for 5 times, and finally stop at the fretting angle of 143°→continue to load to the maximum torsion angle of 188°→unload to the minimum torsion angle of 97°. After each working cycle of the torsion spring, measure the torque value of its maximum torsion angle of 188°, and compare it with the initial torque value before the test. If the torque value decreases by more than 5%, the test ends; if the torque value decreases b...

Embodiment 2

[0056] In this embodiment, the actual working condition parameters of the torsion spring are shown in Table 3 below, and the torsion spring has completed 15,000 working cycle stress relaxation tests, and the working cycle curve of each cycle is shown in image 3 , from Table 3 and image 3 It can be seen that the actual working condition of the torsion spring is: first load the torsion spring to the minimum torsion angle of 82°→continue to load to the inching angle of 107°→vibrate 14 times near (107°±10°), and finally stop At the micro-motion angle of 107°→continue to load to the maximum torsion angle of 142°→unload to the minimum torsion angle of 82°. After each working cycle of the torsion spring, measure the torque value of its maximum torsion angle of 142°, and compare it with the initial torque value before the test. If the torque value decreases by more than 10%, the test ends; if the torque value decreases by less than 10%, continue The test ends after 15,000 working c...

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Abstract

The invention relates to the field of stress testing of torsion springs, in particular to a dynamic testing method for stress relaxation of torsion springs. The computer program is used to control the cyclic load loading mode of the torsion testing machine to simulate the actual working conditions of the torsion spring. Each cycle contains several fretting cycles; according to the working conditions, within the range of the upper and lower torsion angles including the upper and lower limits, At any angle during the loading and / or unloading process, load the required number and amplitude of micro-motion cycles, measure the torque value of the torsion spring after multiple full cycles, and compare it with the initial torque value before the test to determine its stress relaxation behavior. The test method of the invention can accurately reflect the stress relaxation situation of the torsion spring in actual use, accurately predict the service life of the torsion spring, and has practical significance.

Description

technical field [0001] The invention relates to the field of stress testing of torsion springs, in particular to a dynamic testing method for stress relaxation of torsion springs. Background technique [0002] For springs or other elastic elements, when they are subjected to static loads or dynamic alternating loads, the phenomenon that the bearing capacity decreases with the extension of the load time will occur, which is called stress relaxation or elastic decline. This is the spring and elastic elements in service. Common failure modes in the process. Therefore, testing and predicting the stress relaxation behavior of the spring is an important means to study the service life of the spring. Although, as early as 1868, J.c. Maxwell conducted relevant research on the law of stress relaxation and its influencing factors, but so far people have not established a unified theory on the mechanism and conditions of stress relaxation, and there is no general stress relaxation tes...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01M5/00G01N3/32
CPCG01M5/0041G01N3/32
Inventor 张慧博李志鹏金伟任德春
Owner INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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