Adjust the tooth height correction factor KP during small wheel machining. Different values of the tooth height correction factor are listed in the table to study its impact on the contact condition.

Serial number	a	b	c	d	e
Tooth height correction factor	-0.05	0	0.05	0.1	0.15

TCA analysis shall be carried out respectively according to the correction coefficient values of small and medium tooth height in the above table, and the contact conditions are shown in the figure.

By observing the change of contact area and motion curve, when the correction coefficient of small gear tooth height is adjusted in the positive direction, the inner diagonal contact is generated, and the fishtail contact phenomenon is intensified. When the correction coefficient of small gear tooth height is adjusted in the negative direction, the inner diagonal contact phenomenon is reduced, the outer diagonal is generated, and the fishtail contact is improved; By observing the change of the slope k<0 of the motion curve when the abscissa is 0, the correction coefficient of the pinion tooth height is adjusted in the positive direction, and the slope k of the motion curve when the abscissa is 0, the contact area moves to the tooth root; The tooth height correction coefficient of the small gear is adjusted in the negative direction, the slope of the motion curve when the abscissa is 0 is k>0, and the contact area moves towards the tooth top.