Development and Research on Injection Molding Plastic Gear with Positive Utilization of Injection Deformed Layer

注塑成型的塑料齿轮需要是齿轮强度或寿命方面的薄变形层。然而，对低噪声齿轮的需求越来越大，对免维护齿轮的发展也越来越迫切。在这样的背景下，在注塑齿轮上形成正变形层的建议对注塑塑料齿轮的静音是有用的。本研究考察了在不同成型条件下制作的齿轮的噪声和磨损特性，以期积极地利用变形层开发出具有良好静音性能的塑料齿轮。选用聚缩醛共聚树脂和均聚树脂作为齿轮材料，在不同的成型条件下加工出注塑塑料齿轮。为了澄清这些齿轮的噪声，在功率吸收式齿轮试验机上进行了实验。通过一系列实验表明，变形层厚度较薄的齿轮具有较高的噪声水平，变形层厚度的影响被接受，并通过施加在齿轮上的载荷的大小来表明，随着硬度的不同，对噪声水平和磨损量的影响也不同。此外，在高负荷的情况下，运行早期出现的积分倍数的接合频率的峰值从这些频率移位。从显微照片上可以看出，这些牙齿的齿形已经明显塌陷。因此，为了改善低噪声，人们认为需要施加变形层作为齿轮的使用，以正向地用于施加载荷不需要的旋转传递。为解决注塑齿轮的静音问题提供了宝贵的数据。

The injection molding plastic gear needs to be a thin deformed layer in respect of gear intensity or it's life. However, the demand to low noise gear increases and development of the maintenance free gear is desired. The proposal of using positive deformed layer produced on an injection molding plastic gear from such a background is useful to the silence of an injection molding plastic gear. This research examined the noise and the wear characteristic of the gear made under various molding conditions in order to consider it as an aid of development of a plastic gear which was excellent in silence using a deformed layer positively. Two kinds of resin, polyacetal co-polymer and homo-polymer, were chosen as gear material, and the injection molding plastic gears were manufactured under various molding conditions. In order to clarify noise of these gears, the experiment by using a power absorption type gear testing machine was performed. By a series of experiments, the gear with thinner deformed layer thickness had the higher noise level, and the influence of the thickness of a deformed layer was accepted, and it was shown by the size of the load given to the gear in operation that the influence on a noise level and the amount of wear changed with differences of the hardness. Moreover, in the case of high load, the peak of the engagement frequency of the integral multiple which had appeared in early stages of operation shifted from those frequency. It was admitted from the microphotograph that the tooth profile had collapsed remarkably about these. Therefore, it is thought desirable to apply a deformed layer as a use of the gear used positively to the rotation transfer which applied load does not require in order to improve low noise. The precious data for contributing to the silence of an injection molding plastic gear by the above were able to be obtained.