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DE-102024132925-A1 - Method for manufacturing a rotor of a screw compressor or a workpiece with a helical profile

DE102024132925A1DE 102024132925 A1DE102024132925 A1DE 102024132925A1DE-102024132925-A1

Abstract

The invention relates to a method for manufacturing a rotor (1, 2) of a screw compressor or a workpiece with a helical profile, wherein the rotor (1, 2) or the workpiece with a helical profile has a number of helically extending profiles in the form of groove-shaped recesses (3, 4) on its outer circumference, wherein the groove-shaped recesses (3, 4) of the rotor (1, 2) or the workpiece with a helical profile have a variable pitch over the axial course of the rotor (1, 2) or the workpiece with a helical profile, and wherein the groove-shaped recesses (3, 4) are finely machined by means of a grinding tool (5) in order to produce a precise profiling. In order to enable the production of rotors or workpieces with a variable pitch over the axial extent of the rotor or workpiece as precisely as possible and in as little time as possible, the invention provides that a dressable grinding wheel is used as the grinding tool (5), wherein the grinding of the groove-shaped recesses (3, 4) is carried out by means of a number of grinding strokes, wherein the grinding tool (5) is dressed at least once between two grinding strokes and wherein the target geometry of the grinding tool (5) to be ground is changed during the intermediate dressing.

Inventors

  • Leon Köhler

Assignees

  • KAPP NILES GmbH & Co. KG

Dates

Publication Date
20260513
Application Date
20241111

Claims (10)

  1. A method for manufacturing a rotor (1, 2) of a screw compressor or a workpiece with a helical profile, wherein the rotor (1, 2) or the workpiece with a helical profile has a number of helically extending profiles in the form of groove-shaped recesses (3, 4) on its outer circumference, wherein the groove-shaped recesses (3, 4) of the rotor (1, 2) or the workpiece with a helical profile have a variable pitch over the axial course of the rotor (1, 2) or the workpiece with a helical profile, and wherein the groove-shaped recesses (3, 4) are finely machined by means of a grinding tool (5) to produce a precise profile, characterized in that a dressable grinding wheel is used as the grinding tool (5), wherein the grinding of the groove-shaped recesses (3, 4) is carried out by means of a number of grinding strokes, wherein the grinding tool (5) is dressed at least once between two grinding strokes, and wherein during the dressing, the The grinding target geometry of the grinding tool (5) is changed.
  2. Procedure according to Claim 1 , characterized in that the grinding tool (5) is dressed at least twice in between.
  3. Procedure according to Claim 1 or 2 characterized in that the target geometry of the grinding tool to be ground is completely or only partially changed during intermediate dressing.
  4. Procedure according to Claim 3 , characterized in that the desired geometry of the grinding tool to be changed relates to the shape of the groove-shaped recesses (3, 4) over the radial extent, in particular the change of the head and/or foot radii of the groove-shaped recesses (3, 4).
  5. Procedure according to one of the Claims 1 until 4 , characterized in that the grinding tool (5) has a left flank (6') and a right flank (6"), wherein the two flanks (6', 6") are provided with different contours during dressing, wherein preferably the left flank (6') and the right flank (6") are provided with different radii of curvature during dressing.
  6. Procedure according to one of the Claims 1 until 5 , characterized in that during the fine machining of the groove-shaped recesses (3, 4) by means of the grinding tool (5) there is a point contact (P) between the surface (7) of the groove-shaped recess (3, 4) and the grinding tool (5).
  7. Procedure according to one of the Claims 1 until 6 , characterized in that the entire surface (7) to be machined of the groove-shaped recess (3, 4) is machined by traversing it line by line using the grinding tool (5).
  8. Procedure according to Claim 7 , characterized in that the line-by-line traversing is carried out by performing a number of grinding strokes in which the grinding tool (5) is moved in a radial direction (r) relative to the rotor (1, 2) or to the workpiece with a helical profile, and/or by performing a number of grinding strokes in which the grinding tool (5) is moved in an axial direction (a) relative to the rotor (1, 2) or to the workpiece with a helical profile.
  9. Procedure according to one of the Claims 1 until 8 , characterized in that , during grinding of the groove-shaped recesses (3, 4), the axis of rotation (a) of the rotor (1, 2) or of the workpiece with a helical profile and the radial infeed movement (r) of the grinding wheel (5) are changed interpolating relative to each other, or that, during grinding of the groove-shaped recesses (3, 4), the axis of rotation (a) of the rotor (1, 2) or of the workpiece with a helical profile and the feed axis (v) are changed interpolating relative to each other in the direction of the axis of rotation (a) of the rotor (1, 2) or of the workpiece with a helical profile.
  10. Procedure according to Claim 9 , characterized in that , during grinding of the groove-shaped recesses (3, 4), the pivot axis (B) of the grinding tool (5) and/or the feed axis (t) of the grinding wheel (5) are further changed interpolating in the axial direction (b) of the grinding wheel (5).

Description

The invention relates to a method for manufacturing a rotor of a screw compressor or a workpiece with a helical profile, wherein the rotor or the workpiece with a helical profile has a number of helically extending profiles in the form of groove-shaped recesses on its outer circumference, wherein the groove-shaped recesses of the rotor or the workpiece with a helical profile have a variable pitch over the axial course of the rotor or the workpiece with a helical profile, and wherein the groove-shaped recesses are finely machined by means of a grinding tool in order to produce an exact profile. A generic method for manufacturing a screw compressor rotor with variable pitch is derived from the DE 10 2019 124 394 A1 It is well known that manufacturing such variable-pitch rotors is time-consuming and inflexible using tools with a steel body coated with an abrasive material (CBN). Furthermore, optimal grinding is not always possible due to the sometimes required small radii on the tool. The invention is based on the task of further developing a generic method for the fine machining of the rotors of a screw compressor or a workpiece with a helical profile in such a way that the workpiece can be manufactured as accurately as possible, with the least possible time required for production. The solution to this problem by the invention provides that a dressable grinding wheel is used as the grinding tool, wherein the grinding of the groove-shaped recesses is carried out by means of a number of grinding strokes, wherein the grinding tool is dressed at least once between two grinding strokes and wherein the target geometry of the grinding tool to be ground is changed during the intermediate dressing. The grinding tool is preferably dressed at least twice during the intermediate dressing process. For example, two, three, four, five, or six dressing operations can be performed. The target geometry of the grinding tool to be ground can be completely changed during intermediate dressing, i.e. over the entire profile height, but it is also possible that the target geometry is only partially changed. In particular, it may be intended that the modified target geometry of the grinding tool relates to the shape of the groove-shaped recesses along their radial extent. This specifically includes changes to the head and/or foot radii of the groove-shaped recesses. The grinding tool preferably has a left flank and a right flank, the two flanks being provided with different contours during dressing. The left flank and the right flank can be provided with different radii of curvature during dressing. The grinding tool can have a head radius at its outer end, with the head radius being designed differently during dressing. When fine-tuning the groove-shaped recesses using the grinding tool, a point contact between the surface of the groove-shaped recess and the grinding tool is preferably present (topological grinding). The entire surface of the groove-shaped recess to be machined can be processed by traversing it line by line with the grinding tool. This line-by-line processing can be achieved by performing a number of grinding strokes in which the grinding tool is moved radially relative to the rotor or the workpiece with a helical profile, and/or by performing a number of grinding strokes in which the grinding tool is moved axially relative to the rotor or the workpiece with a helical profile. When grinding the groove-shaped recesses, the axis of rotation of the rotor or the workpiece with a helical profile and the radial infeed movement of the grinding wheel can be changed relative to each other in an interpolating manner. Alternatively, it can be provided that, when grinding the groove-shaped recesses, the axis of rotation of the rotor or the workpiece with a helical profile and the feed axis are changed relative to each other in an interpolating manner in the direction of the axis of rotation of the rotor or the workpiece with a helical profile. It is preferably provided that, when grinding the groove-shaped recesses, the pivot axis of the grinding tool and/or the feed axis of the grinding wheel are also changed in an interpolating manner in the axial direction of the grinding wheel. The proposed method therefore involves the use of ceramic profile grinding wheels that can be dressed. The profile grinding wheel can always be provided with the optimal profile or head radius by appropriate intermediate dressing, and thus be profiled in the best possible way to the geometry currently being ground. Different profiles are possible on the left and right flanks of the grinding wheel; in particular, different radii or different radius positions are possible. The time required for dressing can be more than compensated for by the fact that fewer grinding strokes are required than with previously known methods. In particular, the cycle time of production can be advantageously reduced, since by changing the geometry of the grinding wheel by