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课堂教学是学生掌握系统知识,发展个性能力的基本学习形式。在课堂上应用模具模型,进行演示法教学,有利于帮助学生理解和验证知识,培养其观察能力和思维能力。具体方法有四条。 1.最大限度地发挥现有模型的演示作用。如使用直齿圆柱齿轮传动模型、蜗杆传动模型时,一方面可对齿轮、蜗杆、蜗轮的结构特点作直观分析;另一方面又可利用已知两齿轮(或蜗杆、蜗轮)的齿数,在控制主动轮的转速条件下,来验证N_1Z_1=N_2Z_2,得传动比i_(12)=N_1/N_2=Z_2/Z_1。2.利用自制模具进行启发式教学。在《机械基础》中,齿轮的渐开线齿廓的形成及其特点是整个传动系统的重点,也是教学难点。为此,可利用一圆柱木块,在圆木的圆周上绕一线绳,线绳一端固定于木块上,另一端系上粉笔。当线绳在木块圆周绕制方向反向放开的同时,线绳上任意一点的轨迹即为渐开线,并作出渐开线齿廓(注意形成渐
Classroom teaching is a basic form of learning for students to master system knowledge and develop individual ability. Applying the mold model to the demonstration teaching in the classroom helps students to understand and verify the knowledge and cultivate their observation and thinking ability. There are four specific ways. 1. To maximize the demonstration of the existing model. Such as the use of straight-tooth cylindrical gear drive model, the worm drive model, on the one hand the gear, worm, worm wheel structural features for intuitive analysis; the other hand can use the known two gear (or worm, worm wheel) Under the control of the rotating speed of the driving wheel, the N_1Z_1 = N_2Z_2 is verified to obtain the transmission ratio i_ (12) = N_1 / N_2 = Z_2 / Z_1.2. The heuristic teaching is made by self-made mold. In the “mechanical basis”, the gear involute profile formation and its characteristics is the focus of the entire transmission system, but also teaching difficulties. To this end, it is possible to use a cylindrical block of wood, around which a rope is wound on the circumference of the log, one end of which is fastened to the block of wood and the other end to the chalk. When the rope in the wood around the circumference of the direction of reverse release at the same time, the line at any point of the track is the involute and involute tooth profile (pay attention to the formation of gradually