# HelicalGear

Model ElementSpecifies a helical gear element.

HelicalGear

## Description

The HelicalGear is defined by the following dimensions (see comment 9):

## Attributes

The table below summarizes the attributes of the HelicalGear classes.
Variable Type Notes Symbol
id Int() Unique identification number.
label Str() Descriptor of the gear element.
rm Reference("Marker", required=True) The reference marker of the gear element. This marker points to the center of the gear. Defines the orientation of the gear (z axis of reference marker is the gear’s axial axis).
module Double(required=True) The normal module of the gear. ${m}_{n}$
num_of_teeth Int(required=True) The number of gear teeth (see comment 7). $z$
pressure_angle Double(required=True) The normal pressure angle in degrees. ${a}_{n}$
helix_angle Double(required=True) The helix angle at the pitch diameter in degrees. $\beta$
width Double(required=True) The width of the gear element. $b$
addendum_coefficient Double(1.0) The basic rack addendum coefficient. ${h}_{a}^{*}$
dedendum_coefficient Double(1.25) The basic rack dedendum coefficient. ${h}_{f}^{*}$
tool_tip_radius_coefficient Double(0.38) The basic rack tool tip radius coefficient. ${r}_{f}^{*}$
profile_shift_coeff Double(0.0) The profile shift coefficient of the gear (see comment 6). ${x}^{*}$
hub_diameter Double(0.0) The inner/outer diameter of the gear (see comment 8). ${d}_{i/o}$
backlash_ratio Double(0.04) The circumferential backlash ratio of the small gear. The range must be 0.03 – 0.05 (see comment 2). ${j}^{*}$
addendum_lowering Double(0.0) The change to the addendum of the gear teeth due to the profile shift (see comments 1, 3). $km$
connection_part Reference(“Part", required=True) The part that is connected to the gear.
connection_type Enum("REVOLUTE FIXED", default=" FIXED ") The type of connection between the gear and the connection part.
num_curve_segments Int(10) The number of mesh segments along the involute profile of the gear. When using a non-uniform mesh, this parameter is always an even number (the profile is split into two symmetric regions).
num_width_segments Int(20) The number of mesh segments along the gear's width.
non_uniform_factor Double(1.2) Defines the factor of the mesh’s non-uniformity. The length of a triamesh element is equal to the previous element length times this factor. Use 1.0 for uniform mesh.
density Double() The density of the gear's material (see comment 4).
export_graphic Bool(False) Exports the gear's geometry to a *.stl file. This file can be re-meshed in HyperMesh.
export_parameters Bool(False) Exports the calculated gear's parameters in a *.json file.

## Example

g = HelicalGear(
id=1,
label='Helical gear',
rm=Marker(part=ground),

module=1.0,
num_of_teeth=17,
pressure_angle=20.0,
helix_angle=15.0,
width=10.0,

dedendum_coefficient=1.25,
profile_shift_coeff=0.0,

)