Method and apparatus for hard finishing modified gears

Patent metadata

Field	Value
Publication number	US-10173278-B2
Application number	US-201313860433-A
Country	US
Kind code	B2
Filing date	Apr 10, 2013
Priority date	Apr 17, 2012
Publication date	Jan 8, 2019
Grant date	Jan 8, 2019

Abstract

The present disclosure relates to a method for the manufacture of a workpiece having a corrected gear geometry and/or a modified surface structure, in particular by a hard finishing process, in particular generation grinding or honing. Provision is made in this respect that it is achieved by a direct generation of a wobble movement and/or of an eccentricity of the tool that a modification, in particular a profile modification or profile waviness, and/or a defined periodic flank waviness is generated on the active surface of the workpiece machined therewith.

First claim

The invention claimed is:

1. A method for manufacturing a workpiece, comprising:
generating a modified gear flank geometry on an active surface of the workpiece by generation grinding or honing,
wherein the modified gear flank geometry of the workpiece is generated on the active surface of the workpiece by a generation of a wobble movement of a tool or by a modified gear flank geometry of a tool, the tool being used for machining the workpiece by generation grinding or honing, the modified gear flank geometry of the tool being provided by a variation of a gear flank geometry of the tool in dependence on an angular position of the tool,
wherein the workpiece comprises a cylindrical spur gear, a helical gear, a spherical gear, or a conical gear, and
wherein the modified gear flank geometry of the workpiece includes at least one of a profile waviness or a defined periodic flank waviness.

2. The method in accordance with claim 1 ,
wherein generating the modified gear flank geometry of the workpiece includes a hard finishing process,
wherein the tool comprises a worm grinding wheel, and
wherein a width of the worm grinding wheel is selected such that pitch ends of worm pitches at two ends of the worm grinding wheel are arranged at different angular positions at an outer periphery of the worm grinding wheel, thereby directly creating a defined imbalance.

3. The method in accordance with claim 1 , wherein the tool has a defined imbalance, the defined imbalance generating the wobble movement of the tool, and the defined imbalance generating the defined periodic flank waviness on the active surface of the workpiece.

4. The method in accordance with claim 1 , wherein the modified gear flank geometry of the tool is generated during dressing, and
wherein the tool is dressed by a forming roller, and wherein the variation of the gear flank geometry of the tool in dependence on the angular position of the tool comprises the modified gear flank geometry of the tool being formed by varying an engagement depth of the forming roller during dressing of the tool in dependence on the angular position of the tool.

5. The method in accordance with claim 4 ,
wherein the forming roller is only in contact with partial regions of a tooth between a base and a crest during the dressing, forming the modified gear flank geometry of the tool in a plurality of strokes, the plurality of strokes having different relative positions over a total tooth height.

6. The method in accordance with claim 1 , wherein the modified gear flank geometry of the tool generates a defined flank waviness in a diagonal grinding process on the active surface of the workpiece.

7. The method in accordance with claim 4 , wherein one or more corrections are performed during the dressing of the tool, the corrections comprising:
a. varying an axial spacing of a dresser from the tool based on an angle of rotation of the tool or based on a tool width;
b. varying an axial feed of the tool or of the dresser based on the angle of rotation of the tool or based on the tool width;
c. varying a crossed-axis angle of the tool and of the dresser based on the angle of rotation of the tool or based on the tool width; and
d. varying a tool speed in dependence on the angle of rotation of the tool or based on the tool width.

8. The method in accordance with claim 4 , wherein the dressing of the tool includes a dresser being fed toward the tool based on the angular position of the tool or the tool being fed toward the dresser based on the angular position of the tool.

9. The method in accordance with claim 1 , wherein the modified gear flank geometry of the workpiece has a constant value at least locally in a first direction of the workpiece and is given by a predefined function f(x) in a second direction of the workpiece which extends perpendicular to the first direction of the workpiece, and
wherein the modified gear flank geometry of the tool has a constant value in a generation pattern at least locally in a first direction of the tool and is further given by a predefined function f(cx), where c is a linear compression factor, in a second direction of the tool perpendicular to the first direction.

10. The method in accordance with claim 4 , wherein the modified gear flank geometry of the tool has a constant value at least locally in a first direction of the tool, is given by a function f(x) in a second direction of the tool which extends perpendicular to the first direction of the tool,
wherein the first direction of the tool in which the modified gear flank geometry of the tool has a constant value corresponds to a line of engagement of a dresser, and
wherein the first direction of the tool is at least locally approximated by a straight line.

11. The method in accordance with claim 9 , wherein one or more of a macrogeometry of the tool, a line of engagement of a dressing tool, an axial feed of the workpiece, a shift movement of the tool, and the linear compression factor c are selected so that the modified gear flank geometry of the tool along a first line corresponds to the modified gear flank geometry of the workpiece along a second line,
wherein the first line comprises a line on which a contact point moves on the tool during the manufacture of the workpiece, and
wherein the second line comprises a line on which the contact point moves on the workpiece.

12. The method in accordance with claim 11 , wherein, if the macrogeometry of the tool and the line of engagement of the dressing tool are predefined, then at least one or more of the axial feed of the workpiece, the shift movement of the tool, and the linear compression factor c are selected based on the macrogeometry and the line of engagement,
wherein, if the axial feed of the workpiece is predefined, then at least one or more of the shift movement of the tool and the compression factor c are selected based on the axial feed of the workpiece,
wherein at least one or more of the macrogeometry of the tool, the line of engagement of the dressing tool, the axial feed of the workpiece, the shift movement of the tool, and the compression factor c are selected so that the dressing of the tool and the modified gear flank geometry of the workpiece also correspond along third and fourth lines, and
wherein the third and fourth lines are displaced by the axial feed of the workpiece and by the shifting of the tool with respect to the first and second lines.

13. The method in accordance with claim 1 , wherein the modified gear flank geometry of the workpiece includes the defined periodic flank waviness in a first direction of a flank of the workpiece, the flank not having said defined periodic flank waviness in a second direction, perpendicular to the first direction.

14. The method in accordance with claim 1 , wherein the wobble movement of the tool is generated by varying an infeed position of the tool in dependence on the angular position of the tool.

15. The method in accordance with claim 4 , wherein the forming roller is in contact with a tooth of the tool from a base region up to a crest region during the dressing, forming the modified gear flank geometry of the tool in one stroke over a whole tooth height.

16. The method in accordance with claim 4 , wherein the tool is dressed in the same apparatus as is used to machine the workpiece.

17. The method in accordance with claim 9 , wherein the modified gear flank geometry of the workpiece is defined at least locally in the generation pattern at a generation length position L 2 and at a tooth width position b 2 by the formula:
f

Assignees

• Liebherr Verzahntech Gmbh

Inventors

• Geiser Hansjoerg
• Wuerfel Robert

Classifications

• B23F21/026

  Grinding worms · CPC title

• Y10T29/49467

  Gear shaping · CPC title

• B23F19/12 Primary

  by grinding · CPC title

• B23F5/04 Primary

  the tool being a grinding worm · CPC title

• B23F23/10

  Arrangements for compensating irregularities in drives or indexing mechanisms · CPC title