| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an electric power steering device employing a worm gear as a reduction gear, which solves the problem that although a worm wheel is made of a resin material to realize weight reduction and noise reduction, the recycle and reuse are absolutely required from recent demands of environmental responsibility and cost reduction but the recycle cannot be achieved owing to the deterioration of durability life caused by the occurrences of thermal deterioration at the time of remolding for recycle and the occurrences of viscocity degradation due to hydrolysis. <P>SOLUTION: In a worm wheel 10, water content ratio at the time of molding a polyamide resin is made to 0.02% or lower by adding aliphatic polycarbodiimide or aromatic polycarbodiimide to a polyamide resin by 0.5-3 wt.% at the time of repelletizing and molding. The worm wheel 10 is molded at 290°C or lower, wherein a melt viscosity thereof is 1,500-15,000 Pa S. <P>COPYRIGHT: (C)2011,JPO&INPIT |
