Methods and apparatus for generating control data for forming a tooth of a spur gear toothing by milling a workpiece at a machine tool

• US 8,903,537 B2
• Filed: 08/18/2011
• Issued: 12/02/2014
• Est. Priority Date: 08/18/2010
• Status: Active Grant

• Current Assignee: Deckel MAHO Pfronten GmbH (Dmg Mori Co., Ltd.)
• Original Assignee: Deckel MAHO Pfronten GmbH (Dmg Mori Co., Ltd.)
• Inventors: Neumaier, Josef, Lochbihler, Thomas, Hansen, Uwe-Carsten
• Primary Examiner(s): KASENGE, CHARLES R
• Application Number:
  US13/212,756
• Publication Number:
  US 20120072009A1
• Time in Patent Office: 1,202 Days
• Field of Search: 700/95, 700/97, 700/98, 700/159, 700/160, 700/164, 700/180, 700/182, 700/186, 700/187, 700/195, 451/5, 451/8, 451/11, 451/28, 451/57, 451/58, 703/1, 703/7
• US Class Current: 700/159
• CPC Class Codes: G05B 19/182 characterised by the machine tool function, e.g. thread cutting, cam making, tool direction control G05B19/21 - G05B19/40 take precedence
• CPC Class Codes: G05B 19/186 Generation of screw- or gearlike surfaces

Abstract

A disclosed example method for generating control data for forming a tooth of a spur gear toothing which has an intended widthwise crowning by milling a workpiece at a numerically controlled machine tool having at least 5 axes, at a universal machine tool, by successively moving a milling cutter of the machine tool along a plurality of machining paths based on the generated control data, involves providing a tooth flank geometry of at least one tooth flank of the tooth of the spur gear toothing. The method also involves determining parameters for specifying a change of the provided tooth flank geometry according to the intended widthwise crowing of the tooth. In addition, the method involves generating control data based on a tooth flank geometry which is changed based on the determined parameters, wherein the changed tooth flank geometry corresponds to a tooth flank geometry of the tooth having the intended widthwise crowing.

Claims

1. A method for generating control data for forming a tooth of a spur gear toothing which has an intended widthwise crowning by milling a workpiece at a numerically controlled machine tool having at least 5 axes by successively moving a milling cutter of the machine tool along a plurality of machining paths based on the generated control data, the method comprising:

providing a tooth flank geometry of at least one tooth flank of the tooth of the spur gear toothing,

determining parameters, which include a plurality of shift parameters, for specifying a change of the provided tooth flank geometry according to the intended widthwise crowning of the tooth, each shift parameter being associated with one of plural shift positions of the at least one tooth flank of the provided tooth flank geometry, and

generating, by a processor, control data based on a tooth flank geometry which is changed based on the determined parameters, wherein the changed tooth flank geometry corresponds to a tooth flank geometry of the tooth having the intended widthwise crowning,

wherein the changed tooth flank geometry is retracted, at each of the plural shift positions, by an amount according to the respective associated shift parameter relative to the provided tooth flank geometry by changing the provided tooth flank geometry such that the tooth profile of the tooth flank is shifted, at each of the plural shift positions, by rotating the tooth profile about the rotational axis of the spur gear toothing according to the respective determined shift parameter.

2. A method according to claim 1, wherein generating the control data comprises at least one of:

calculating a model of the changed tooth flank geometry based on the provided tooth flank geometry and the determined parameters, or

calculating a model of the tooth of the spur gear toothing based on the provided tooth flank geometry and the determined parameters.

3. A method according to claim 1, wherein the parameters for changing the tooth flank geometry are determined such that a tooth having the changed tooth flank geometry exhibits the intended widthwise crowning.

4. A method according to claim 1, wherein the plural shift positions are defined on a tooth flank curve of the at least one tooth flank, the tooth flank curve corresponding to a line of intersection of an intersection surface of the tooth and the at least one tooth flank of the provided tooth flank geometry.

5. A method according to claim 4, wherein the intersection surface of the tooth is an intersection plane, in particular a horizontal intersection plane.

6. A method according to claim 5, wherein the intersection plane is oriented tangential to a pitch circle of the spur gear toothing, in particular wherein the intersection plane is oriented tangential to the pitch circle of the spur gear toothing at a centric position of the intersection plane.

7. A method according to claim 4, wherein the intersection surface of the tooth extends along a cylindrical surface, an axis of the cylindrical surface being oriented coaxially with respect to a rotational axis of the spur gear toothing.

8. A method according to claim 7, wherein the intersection surface of the tooth extends along a pitch circle of the spur gear toothing.

9. A method according to claim 1, wherein the plural shift positions are defined substantially at the same level as a pitch circle of the spur gear toothing.

10. A method according to claim 1, further comprising displaying a model of the changed tooth flank geometry.

11. A method according to claim 1, wherein providing the tooth flank geometry comprises:

providing toothing information data, and

calculating the provided tooth flank geometry based on the provided toothing information data.

12. A method according to claim 11, wherein the toothing information data comprises at least one of:

data indicative of a size and shape of the workpiece,

data indicative of a toothing shape including at least one of a straight toothing shape, a helical toothing gear shape or a spiral toothing shape, data indicative of a profile shape of a tooth flank including at least one of an involutes profile shape, a cycloidal profile shape or a circular profile shape,

data indicative of a size and shape of a tooth geometry of the gear toothing, or

data indicative of a number of teeth of the gear toothing.

13. A non-transitory computer-readable medium having instructions stored thereon that, when executed, cause a machine to perform the method of claim 1.

14. An apparatus for generating control data for forming a tooth of a spur gear toothing which has an intended widthwise crowning by milling a workpiece at a numerically controlled machine tool having at least 5 axes by successively moving a milling cutter of the machine tool along a plurality of machining paths based on the generated control data, the apparatus comprising:

first input means for providing a tooth flank geometry of at least one tooth flank of the tooth of the spur gear toothing,

second input means for determining parameters, which include a plurality of shift parameters, for specifying a change of the provided tooth flank geometry according to the intended widthwise crowning of the tooth, each shift parameter being associated with one of plural shift positions of the at least one tooth flank of the provided tooth flank geometry, and

control data generating means for generating control data based on a tooth flank geometry which is changed based on the determined parameters, wherein the changed tooth flank geometry corresponds to a tooth flank geometry of the tooth having the intended widthwise crowning,

wherein the changed tooth flank geometry is retracted, at each of the plural shift positions, by an amount according to the respective associated shift parameter relative to the provided tooth flank geometry by changing the provided tooth flank geometry such that the tooth profile of the tooth flank is shifted, at each of the plural shift positions, by rotating the tooth profile about the rotational axis of the spur gear toothing according to the respective determined shift parameter.

15. A numerically controlled machine tool having at least 5 axes for milling a workpiece by successively moving a milling cutter of the machine tool along a plurality of machining paths based on the generated control data, the machine tool comprising an apparatus according to claim 14.