Helical gears of parallel axle and external engagement can realize co-rotating transmission through analyzing the character of the engagement of involutes helical gear outline.

• 通过对渐开线斜齿轮齿廓啮合特点的分析,表明平行轴外啮合斜齿轮可实现同向传动。并建立实现同向传动齿轮的正确啮合及连续传动条件。