Question TETSU 2006/3/1(Wed) 15:48
Nice to meet you. I designed an extension spring (SWP-B) within the allowable value and operated it 1 million times, but the specified load dropped by about 1% before and after the processing process. Since the JIS tolerance is ± 8%, I think it is in a negligible range, but is this phenomenon usually happen?
Answer Tokai Spring 2006/3/2(Thu) 14:56
Thank you for writing to us, TETSU! Actually, there is a possibility that some load loss may occur due to working stress and heat treatment during manufacturing. In addition, there is a possibility that this is caused by the initial permanent deformation!
Answer TETSU 2006/6/22(Thu) 9:12
Thank you very much. What is the reason for the initial permanent deformation? (Strictly speaking, is it because the stress-strain curve is not linear?)
Answer Tokai Spring 2006/6/22(Thu) 11:36
Hello TETSU! If the stress-strain curve exceeds the elastic limit, it may not be linear. Also, in a high-temperature environment, when certain stress is applied to the material for a long time, the strain is large at the beginning, but the strain gradually decreases and eventually disappears. This often happens to springs. Even at room temperature, the phenomenon is more likely to occur, though not as much as at high temperatures.
Answer Azril 2021/11/12(Fri) 11:06
Hi,
Can please help to share the calculation for lift up force from extension hook spring?
Thank you
Answer Tokai Spring 2021/11/12(Fri) 16:28
Dear Azril,
Please check the formulas here for your reference:
If you have any other questions, please do not hesitate to contact us anytime!
Best regards,
Tokai Spring’s Support Team
We are happy to answer any inquiries regarding technology, specifications, materials, etc. Please feel free to ask.