Method and device for fine machining a toothed workpiece, and program for controlling said device

Abstract

A method and a device for the fine-machining of a toothed workpiece with a toothed finishing tool (10) which meshes with the workpiece in mutual tooth engagement are, for the purpose of producing conically modified tooth flanks, designed according to the invention in such a way that in the dressing process the finishing tool (10) and the dressing tool (11) are set at a position of reduced center distance (a) that is offset from a position of maximum center distance.

Claims

1. Method of fine-machining of a toothed workpiece (12), using a toothed finishing tool (10), said method comprising: meshing said toothed finishing tool with the workpiece (12) in mutual tooth engagement, said finishing tool (10) being dressed in accordance with a dressing process in which the finishing tool (10) and a toothed dressing tool (11), in tooth engagement with each other, rotate about their respective gear axes (C2, C1) which are arranged relative to each other at a center distance (a) different from zero and an axis-crossing angle different from zero, characterized in that the gear axes (C2, C1) of the finishing tool (10) and of the dressing tool (11) are arranged relative to each other in a position that is offset from the position of maximum center distance (a′) to a position of reduced center distance (a).

2. Method according to claim 1, characterized in that the toothed contour of the finishing tool (10) is an internal toothed contour, while the toothed contour of the dressing tool (11) is an external toothed contour.

3. Method according to claim 1, characterized in that the toothed contour of the finishing tool (10) is an external contour, while the toothed contour of the dressing tool (11) is an internal contour.

4. Method according to claim 1 characterized in that the finishing tool (10) is a ring-shaped honing tool.

5. Method according to claim 1 characterized in that the tooth thickness of the dressing tool (11), disregarding tooth trace convexities, is constant over the tooth width.

6. Method according to claim 1 characterized in that a superimposed movement component parallel to the gear axis (C1) of the dressing tool (11) is added to the relative movement between the latter and the finishing tool (10).

7. Method according to claim 1 characterized in that a superimposed movement component orthogonal to the gear axis (C1) of the dressing tool (11) is added to the relative movement between the latter and the finishing tool (10).

8. Method according to claim 1 characterized in that for the machining of the workpiece (12) with the dressed finishing tool (10), their respective gear axes (C1, C2) are positioned relative to each other in such a way that their center distance (a′) is different from the center distance (a) at which the gear axis of the dressing tool (11) and the gear axis of the finishing tool (10) were positioned in the dressing process.

9. Method according claim 8, characterized in that the workpiece (12) is machined with the dressed finishing tool (10) in a position of maximum center distance (a′) between the gear axis (C2) of the finishing tool (10) and the gear axis (C1) of the workpiece (12).

10. Method according to claim 8 characterized in that for the machining of the workpiece (12) the axis-crossing angle between the gear axes (C1, C2) of the workpiece (12) and finishing tool (10) is set to a value which corresponds to the axis-crossing angle at which the gear axes (C1, C2) of the dressing tool (11) and the finishing tool (10) were positioned in the dressing process.

11. Method according to claim 8 characterized in that for the machining of the workpiece (12), the axis-crossing angle between the gear axes (C1, C2) of the workpiece (12) and the finishing tool (10) is set to a value which is offset relative to the axis-crossing angle at which the gear axes (C1, C2) of the dressing tool (11) and the finishing tool (10) were positioned in the dressing process.

12. Method according to claim 8 characterized in that a movement component in the direction of the gear axes (C1, C2) is superimposed on the relative movement between the finishing tool (10) and the workpiece (12) which are in meshing engagement with each other in the machining process.

13. Device for the fine-machining of a toothed workpiece (12), comprising a toothed finishing tool (10) that is rotatable about its gear axis (C2), a toothed dressing tool (12) that is rotatable about its gear axis (C1), a device to set the relative position between the gear axes (C1, C2), and a controller device serving to control the position-setting device, characterized in that the controller device is designed with the capability to perform a setting that enables the method according to claim 1 to be executed.

14. Device according to claim 13, characterized in that the controller device runs under the commands of a program.

15. Device according to claim 14 wherein said program comprises a software program, comprising program code to run the program-controlled controller device.

Description

(1) Further distinguishing features, details and advantages of the invention will become evident from the following description wherein the invention is presented through exemplary details that are illustrated in the attached drawings, wherein

(2) FIG. 1 illustrates the geometrical arrangement of the axes of a conventional gear-honing machine;

(3) FIGS. 2a and 2b schematically represent a relative position between a honing ring and a dressing tool in the dressing process, or between a honing ring and a workpiece in the machining process; and

(4) FIG. 3 schematically represents different relative positions of a honing ring and a dressing tool.

(5) In FIG. 1, the reference symbol C.sub.1 identifies the rotary axis of a workpiece spindle onto which an externally toothed workpiece or an externally toothed dressing tool can be clamped in such a way that the axis of the toothed circumference (also referred to herein as the gear axis) of the workpiece or the dressing tool coincides with the rotary axis C.sub.1. Further, the reference symbol C.sub.2 identifies the rotary axis of a toothed honing tool which serves as finishing tool and is rotatably supported in such a way that its gear axis coincides with the rotary axis C.sub.2. In the following, the two gear axes will therefore be identified likewise as C.sub.1 and C.sub.2.

(6) The crossing angle between the rotary axes or gear axes C.sub.1 and C.sub.2 is adjustable by way of a swivel movement about the swivel axis A. Furthermore, the center distance between the two axes is adjustable along a linear displacement axis X running in the direction of the center distance. In a plane extending transverse to the X-axis, the relative position of the two rotary axes or gear axes C.sub.1 and C.sub.2 is adjustable along a linear displacement axis Y running transverse to the linear displacement axis X and to the rotary axis C.sub.1 and along a linear displacement axis Z running parallel to the rotary axis C.sub.1.

(7) In this system of axes, the drawing plane of FIGS. 2a and 2b extends parallel to the X/Y-plane, and the view is directed parallel to the Z-axis. As the radial plane of the honing ring which forms the circular-shaped fine-machining tool 10 is inclined by the axis-crossing angle against the X/Y-plane that runs parallel to the radial plane of the rotary axis C.sub.1, the fine-machining tool 10 should actually not appear circular in FIGS. 2a and 2b, but rather as an elliptical projection of its circular shape. However, as the drawings are of a purely schematic nature and the axis-crossing angle is normally small, this fine point has been disregarded for the sake of simplicity.

(8) In the representation of FIGS. 2a and 2b, the rotary axes C.sub.1 and C.sub.2 run parallel to the X/Y-plane. Accordingly, the center distance a between the gear axis C.sub.1 of a toothed dressing tool clamped to the workpiece spindle and the gear axis C.sub.2 of the fine-machining tool 10 extends parallel to the x-axis, as is illustrated in FIG. 2a. Likewise, as shown in FIG. 2b, the center distance between the gear axis C.sub.1 of a workpiece 12 clamped to the workpiece spindle and the gear axis C.sub.2 of the fine-machining tool 10 also runs parallel to the X-axis.

(9) As is evident from FIGS. 2a and 2b, the center distance depends on the relative position of the gear axes C1, C2, in which the respective toothed contours of the fine-machining tool 10 and the dressing tool 11 or the workpiece 12 mesh with each other in the dressing or machining process. In the illustrated example, the gear axis C.sub.2 of the fine-machining tool 10 extends in the X/Y-plane, while the gear axis C.sub.1 or the dressing tool 11 or the workpiece 12 extends parallel to the Z-axis. FIG. 2b illustrates the position of maximum center distance a′. In this case, the center distance lies on a radius vector of the fine-machining tool 10 that is oriented orthogonal to the Y/Z-plane.

(10) In the dressing process, the respective gear axes C.sub.2 and C.sub.1 of the fine-machining tool 10 and the dressing tool 11 are set relative to each other at a position of reduced center distance a which is offset from the position of the maximum center distance a′. This is illustrated in FIG. 2a. In the X/Y/Z reference system of this drawing, the gear axis C.sub.1 of the fine-machining tool is offset in the X/Y-plane compared to the position of the maximum center distance a′ which is shown in FIG. 2b. The dressing tool 11 preferably performs a stroke movement in the direction of its gear axis C.sub.1. In addition, movement components directed parallel to the X/Y-plane can be superimposed in a known manner in order to maintain a line contact with the fine-machining tool 10 and/or to generate desired amounts of crowning.

(11) In contrast to the dressing process illustrated in FIG. 2a, the machining of the workpieces 12 with the dressed fine-machining tool 10 takes place in the position illustrated in FIG. 2b, i.e., the position of maximum center distance a′ between the gear axis C.sub.2 of the fine-machining tool 10 and the gear axis C.sub.1 of the workpiece 12.

(12) FIG. 3 represents a view of the dressing process analogous to FIG. 2a, but with the difference that the dressing tool 11 is drawn in three different positions numbered 1, 2 and 3. Shown below the three positions are the respective tooth trace shapes l.sub.1, r.sub.1; l.sub.2, r.sub.2; l.sub.3, r.sub.3 generated on the dressed fine-machining tool. As in FIGS. 2a and 2b, the gear axis C.sub.1 of the dressing tool 11 in FIG. 3 runs parallel to the Z-axis, but the gear axis C.sub.2 of the fine-machining tool 10 is skewed clockwise in the Y/Z-plane by the amount of the axis-crossing angle.

(13) If the dressing tool 11 with cylindrical toothed circumference is arranged in the position 1 of maximum center distance, the teeth of the dressed fine-machining tool 10 will have an addendum modification that is constant over the tooth width, disregarding flank convexities, and whose value can also be zero. In this case, the left and right tooth traces l.sub.1, r.sub.1 are parallel to each other, as shown in FIG. 3. In contrast, if the dressing tool 11 is arranged in one of the positions of reduced center distance 2 or 3, which are offset from the position 1 of maximum center distance, the resultant tooth flank modifications l.sub.2, r.sub.2 and l.sub.3, r.sub.3 will be conical. If the axis-crossing angle is left unchanged during the dressing process, the respective modifications of the left and right flanks will be symmetrical to each other. Since the axis-crossing angle relative to the X/Y/Z system of FIG. 3 has a positive value, the penetration depth of the dressing tool 11 in the position 2 is shallower on the side of the fine-machining tool 10 facing the viewer than on the side facing away from the viewer. Thus, the tooth thickness decreases in the direction of the axis of the fine-machining tool 10, as visualized in FIG. 3 by the tooth traces l.sub.2, r.sub.2. In position 3, on the other hand, the penetration depth of the dressing tool 11 is deeper on the side of the fine-machining tool 10 that faces the viewer. The tooth thickness therefore increases in the direction of the axis of the fine-machining tool 10, as visualized in FIG. 3 by the tooth traces l.sub.3, r.sub.3.

LIST OF REFERENCE SYMBOLS

(14) C.sub.1 axis of rotation of the tool spindle C.sub.2 axis of rotation of the honing tool A swivel axis X linear movement axis in the direction of the center distance Y linear movement axis Z linear movement axis 10 fine-machining tool 11 dressing tool a center distance of dressing tool axis a′ center distance of workpiece axis 12 workpiece l.sub.1, l.sub.2, l.sub.3, r.sub.1, r.sub.2, r.sub.3 tooth flank profiles