Because the hypoid gear pair with less than 5 small teeth is designed, radial displacement and tangential displacement are comprehensively adopted in the design. Therefore, it is necessary to consider the changes of tooth height and tooth root of hypoid gear pair after displacement, and the meshing interference inspection shall be carried out for the designed big tooth top and the tooth root of small wheel, so as to avoid the interference of tooth top or tooth root in the meshing process of hypoid gear pair.
When the large and small wheels of hypoid gear mesh, when the tooth top of one wheel contacts the transition curve tooth profile at the root of the other tooth. Because the protruding part of the transition curve is more obvious than the corresponding involute tooth Gallery, if there is not enough side clearance, the teeth of the two wheels of hypoid gear may be stuck during meshing. Even if there is enough backlash to ensure that the two wheel teeth do not get stuck with each other, the stability of the transmission will be destroyed because the non involute participates in the meshing. This phenomenon of transition curve participating in meshing is called transition curve interference.
The figure shows the interference of the transition curve. In the figure, the tooth profile of segment GF at the root of hypoid gear teeth is the transition curve. It can be seen from the figure that in order to avoid the interference of transition curve, the starting point B of meshing should fall outside the starting point F of involute on the wheel l tooth profile. That is, to satisfy the inequality:
Therefore, the conditions for Hypoid Gear 1 not to produce transition curve interference are as follows:
The conditions for Hypoid Gear 2 not to produce transition curve interference are as follows:
The formula is used for cylindrical gears. When used for Hypoid Gears:
The pressure angle in the formula is the normal pressure angle of hypoid gear, and the convex and concave surfaces should be calculated respectively in the specific calculation.