The research on the influence of shaft intersection angle error on gear hobbing processing is now realized in combination with the specific gear hob and the basic parameters of gear. Basic parameters of gear hob and gear, pressure angle of gear α= 25 °, because the standard pressure angle used in aviation gear transmission in China is α= 25 ° can improve the contact strength and bending strength of aviation gear transmission. The increase of pressure angle can also increase the stiffness of the gear.
In order to clearly observe the influence of the installation axis intersection angle deviation of gear hob on the tooth profile shape, this paper studies by increasing the installation axis intersection angle error value of gear hob. The intersection angle error E Σ of gear hob installation axis is – 0.5 °, – 1 °, – 1.5 °, – 2 °, – 2.5 °, – 3 °. Center distance error e between gear hob and gear α= 0mm。
By changing the axis intersection angle in the gear hobbing simulation model proposed in this paper, the simulation considering the installation axis intersection angle error of gear hob can be realized. As shown in Figure 1, it is the error between the simulated tooth profile of the gear end face and the theoretical involute tooth profile under the condition of the installation angle deviation of different gear hobs. The abscissa represents the pressure angle of different points of the tooth profile, and the ordinate represents the difference between the minimum unfolding length of a certain point on the tooth surface and the theoretical unfolding length.
As shown in Fig. 1, when the installation axis intersection angle error E Σ of gear hob is – 0.5 °, – 1 °, – 1.5 °, – 2 °, – 2.5 °, – 3 °, the corresponding maximum error values are 0.45 respectively μ m，1.25 μ m，2.20 μ m，3.45 μ m，5.00 μ m，7.00 μ m。 When only the intersection angle error of gear hob installation axis is considered, that is, the intersection angle error of gear hob installation axis is not zero, the tooth profile curve is asymmetric, and the error value is the smallest near the tooth profile indexing circle. It can be seen from the above error curve that with the increase of the intersection angle error of the gear hob installation axis, the greater the error value between the gear simulated tooth profile and the theoretical involute tooth profile, the more obvious the asymmetry of the tooth profile curve.
According to the error curves of different shaft intersection angles, since the error value is within a few microns, in order to clearly see the influence of the installation shaft intersection angle error of gear hob on the tooth profile, draw the tooth profile error curve, as shown in Figure 2. The dotted line is the theoretical tooth profile without error, the solid line is the tooth profile considering only the intersection angle error of the gear hob installation axis, and the dotted line is the indexing circle. Only considering the intersection angle error of gear hob installation axis, the tooth profile obtained by simulation is consistent with the given results, which shows that the simulation results of the algorithm proposed in this paper are correct.
It can be seen from Fig. 2 that if there is an installation axis intersection angle error during the installation of gear hob, the machined gear tooth profile will be asymmetric, which will affect the contact state and bending strength of gear tooth surface, so as to reduce the service life of gear. In view of this asymmetry of tooth profile, the solution is to readjust the installation axis intersection angle of gear hob to the appropriate position.