Spiral spring has been used in various mechanical applications because of its simple shape. In automotive reclining seat device, when the seat back is tilted backward, spiral spring is tightened elastically. This provides elastic energy that retracts the seat back to its original position. Therefore, it is important to predict spring characteristics such as torque performance. However, in classical theory, it was impossible to predict them with sufficient accuracy. In actual design, it is necessary to make some prototype springs and measure the characteristics for re-design. Furthermore, accurate shape measurement technology is indispensable for quality assurance for volume production. However, classical method has not been sufficient in accuracy and speed.
In this report, we provide actual examples of the product quality improvement by the design prediction accuracy improvement with CAE and non-contact measurement technology.