Site Variables for Gears

Following are among the site variables related to AxiGrooves:

• axigrooveExtractionEnabled, which allows you to disable and enable AxiGroove extraction. See Disabling and Enabling AxiGroove Extraction.

• Variables that allow you to control what geometry extraction recognizes as an AxiGroove. See Controlling What Gets Recognized as an AxiGroove.

See also Additional Site Variables.

Disabling and Enabling AxiGroove Extraction

In some situations, you might want to disable AxiGroove extraction for all the VPEs at a given stie. For example, if your company does not make gears, but makes many parts with radially symmetric features that can be confused with gears, you should disable AxiGroove extraction. You can disable AxiGroove extraction by setting to false the site variable axigrooveExtractionEnabled. This variable is set to true by default.

Controlling What Gets Recognized as an AxiGroove

When AxiGroove extraction is enabled, aPriori recognizes as AxiGrooves patterns of grooves that meet the following requirements:

• GCD is fully symmetric with respect to an axis. There is no variation among teeth or among valleys; that is, each tooth is just the same as every other tooth, and each valley is just the same as every other valley. For example, the following is not recognized as an AxiGroove:

Note that partial or sector gears are not recognized as AxiGrooves.

• Outside of the GCD must be turnable. The intersection of the tops of the teeth with a plane orthogonal to the turning axis must consist of arcs lying on a circle. In some cases, if the tops of the teeth are planar, the GCD is recognized as an AxiGroove. If the tops of the teeth are tangent to a circle, the GCD is not recognized as an AxiGroove. For example, the following is not recognized as an AxiGroove:

The turnability requirement implies that the tops and valleys must be modeled by separate surfaces.

• For at least half of the GCD’s length, the bottom-most points of each valley must lie on an imaginary cylinder or cone. For example, for non-helical gears, in a longitudinal cross-section (that is, cross-section in which the turning axis is a line), each valley’s bottom is a line. If there are longitudinal bulges, the GCD is generally not recognized as an AxiGroove. aPriori does recognize some AxiGrooves with sufficiently mild valley bulges, as specified by the plant variable axigrooveBulgeOutProfileToleranceFactor, which defaults to 0.4.

The following is not recognized as an AxiGroove:

• Tooth-to-valley volume ratio is within range (0.25 to 3.0, by default). The plant variables axigrooveMinToothToValleyVolumeRatio and axigrooveMaxToothToValleyVolumeRatio specify the minimum and maximum values for tooth volume divided by valley volume. A value of -1 for the maximum value indicates that there is no maximum. A minimum value that exceeds the maximum value indicates that there is no minimum. For example, the following is not recognized as an AxiGroove by default:

• Valley width-to-depth ratio is within range (0.25 to 3.0, by default).The plant variables axigrooveMinValleyWidthToDepthRatio and axigrooveMaxValleyWidthToDepthRatio specify the minimum and maximum values for tooth volume divided by valley volume. A value of -1 for the maximum value indicates that there is no maximum. A minimum value that exceeds the maximum value indicates that there is no minimum.