The main reason for the tooth direction error out of tolerance
The deviation between the vertical feeding direction of the hob and the axis direction of the inner hole of the gear blank is too large.When machining helical gears, there are additional movements that are not correct.
(1) Regarding machine tools and fixtures:
The column triangular guide and the axis of the table are not equal
The end face of the worktable jumps greatly
The upper and lower tops are not on the same axis
The meshing clearance of the indexing worm gear pair is large
There are periodic errors in the transmission of the indexing worm gear pair
Vertical feed screw pitch error is large
The error of split teeth and differential exchange gear is large
(2) Relevant work:
Both ends of the tooth blank are not parallel
The workpiece positioning hole is not perpendicular to the end face
Solution
Focus on controlling the geometric accuracy of the machine tool and the correct installation of the workpiece.
(1) Regarding machine tools and fixtures:
Repair column accuracy, control machine thermal deformation
Fix the rotation accuracy of the table
After repairing the accuracy of the post or the upper and lower thimbles
Reasonably adjust the meshing clearance of the indexing worm gear pair
Fix the part accuracy of the indexing worm gear pair
When the accuracy of the vertical feed screw cannot be achieved due to wear and tear, it should be replaced in time
The calculation error of differential exchange gear should be controlled
(2) Regarding the workpiece
Control the parallelism error of the two end faces of the tooth blank
Control the verticality between the positioning hole of the gear blank and the end face