The main reasons and solutions of tooth direction error in the machining of sprocket gears

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