Tooth flank testing apparatus and method of testing tooth flanks of gears

A method of testing gear flanks of gears with a gear tooth flank testing apparatus which comprises a gear cutting machine containing a bed, a housing erectable upon said bed, two cross-wise arranged carriages, drive means provided for said two cross-wise arranged carriages, displacement path measuring means provided for said two cross-wise arranged carriages, a measuring feeler mounted at said housing by means of said two cross-wise arranged carriages and moveable along two coordinate axes intersecting the lengthwise axis of the gear to be tested, control and evaluation circuit means for guiding said measuring feeler along a tooth flank of the gear to be tested and for comparison of an actual position of the measuring feeler with a predetermined reference position, a feeler element arranged at said housing in spaced relationship from said measuring feeler, said feeler element being capable of being placed into contact with two mutually neighboring tooth flanks of the gear to be tested, two additional cross-wise arranged carriages for freely moveably guiding said feeler element essentially parallel to both of said coordinate axes, a displacement path measuring device operatively associated with each of said additional cross-wise arranged carriages, and said displacement path measuring device being connected with a control and evaluation circuit, comprising the steps of:

• adjusting the housing in relation to the gear to be tested such that the movement plane of the feeler element extends essentially at right angles to the axis of the gear to be tested and the feeler element bears against two mutually neighboring tooth flanks of the gear to be tested;
• rotating the gear about its axis;
• measuring the resultant movements of the feeler element caused by the rotation of the gear in a direction parallel to booth coordinate axes;
• deriving from such measurement the distance of the feeler element from the axis of the gear to be tested as well as the position of such gear axis;
• then rotating the gear about its gear axis while moving the measuring feeler, which is in spaced relationship from the feeler element, along a tooth flank in order to measure the course of the tooth flank, while simultaneously again measuring the movements of the feeler element caused by the rotation of the gear to be tested parallel to both of said coordinate axes;
• utilizing the thus determined angle of rotation of the gear to be tested for the determination of a reference course of the tooth flank;
• and
• comparing said reference course with an actual course of the tooth flank as determined by the measuring feeler.