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KnowledgeBase

FEM wheel bodies

The following tutorial will demonstrate the import, meshing, and positioning of a CAD wheel body.

cad_wheelbody.PNG

The following files are required to following along with this tutorial in the FVA-Workbench:

Gearbox model

CAD wheel body (STEP)

Importing wheel bodies

  1. Load the gearbox model cad_wheelbody.wbpz:

    Project -> Open

  2. Right-click on Cylindrical gear [9] in the Model Tree and add a new wheel body component.

    010_add_Component.png
    020_add_Wheel_Body.png
  3. Right-click on the new wheel body component and choose "import CAD body." Select the cad_wheelbody.stp file. Confirm mm as the unit for the model. The wheel body is initially placed in space independent of the gear model.

    030_import_CAD_Body.png
    051_first_ISO.png

Meshing the wheel body

  1. Right-click on the gear wheel component and select "Run FEM mesher."

    060_run_Mesher.png
  2. Define the center axis

    Click on the bore to determine the center axis. The axis shown must be located exactly in the center of the wheel body.

    070_wheel_center.png
  3. Meshing

    In this tutorial, we will use the default meshing parameters. Click "mesh surface." For more information, see Meshing the wheel body.

    080_wheel_mesher.png
    090_meshed_ISO.png

    If the surface mesh meets your requirements, click "create volume mesh." This completes the meshing.

Positioning the wheel bodies

  1. Right-click on the wheel body component in the Model Tree and select "FEM Wheel Body Wizard."

    100_wheel_wizard.png
  2. Determine the center axis

    Now, select three nodes that form a circle whose center lies on the shaft axis of the gear. It is recommended to select three nodes along the edge of the CAD model. Click "select" and then click on a mesh node.

    120_shaft_positioning.png
    121_shaft_positioning.png

    Notice

    This model contains a cylindrical press fit on the hub side. If the orientation is incorrect, click "reverse axial direction."

  3. Axial positioning

    For the axial positioning, select a node whose axis is located on the left or right edge of the gear.

    122_shaft_positioning.png

    To position the wheel body axially centered on the gear, select a boundary node to be placed under the gear (see image) and enter -5 mm as the distance to the gear face. The prefix (-5 or +5mm) may vary, depending on where the node is selected.

  4. Rotational position of the wheel body

    One, two, or three reference nodes can be selected to define the rotational position of the wheel body relative to a tooth gap. In this case, one of the bores in the wheel body should be used as a reference. Select three nodes that form a circle whose center corresponds to the center of one of the bores.

    130_rotational_position.png

    The position of the wheel body can be precisely specified using the "rotational position relative to the tooth space" input field. The flag shown serves as a guide.

  5. Capture the coupling nodes

    The coupling nodes between the gear and the wheel body are automatically determined. You can visually check whether the snapped nodes meet your expectations. Use the "hide gear" feature to get a better view of the coupling nodes under the gear.

    If the position of the snapped coupling nodes does not meet expectations, adjust the position of the wheel body (or the geometry).

    140_snap_tool.png
    150_final_ISO.png

Calculating

The load distribution calculation, taking the stiffness of the wheel body into account, is performed as a single component calculation on the cylindrical gear stage.

run_fem_wheelbody_calculation.png