cad-Integration/SimpleCADAPI-master/docs/stdlib/make_cycloidal_disc_rsolid.md

make_cycloidal_disc_rsolid

API Definition

def make_cycloidal_disc_rsolid(n_lobes: int, ring_pin_pitch_radius: float, roller_radius: float, eccentricity: float, gear_height: float = 6.0, *, bore_radius: float = 0.0, output_pin_count: int = 0, output_pin_pitch_radius: float = 0.0, output_pin_clearance_radius: float = 0.0, output_pin_phase: float = 0.0, sample_count_per_lobe: int = 33, spline_tolerance: float = 0.005, max_control_points: int = 20) -> Solid

Source: std/gear.py

Import Surface

• standard library: import simplecadapi as scad then scad.std.gear.make_cycloidal_disc_rsolid(...); direct submodule import: from simplecadapi.std.gear import make_cycloidal_disc_rsolid

Description

Create a cycloidal reducer disc for a one-tooth-difference pin ring.

This is a single-disc geometric standard part. Real compact reducers often stack two identical-lobe discs to balance output-pin side loads. In that assembly-level pattern, separate two concepts that are easy to confuse:

• Place the two input eccentric cam centers 180 degrees apart, for example (+e, 0) and (-e, 0), so their orbit loads oppose each other.
• Tooth-index the second cycloidal profile by half a lobe, not by a full 180 degree shape rotation. For a disc with n_lobes lobes, that geometric body phase is 180 / n_lobes degrees. A 10-lobe disc rotated by 180 degrees is exactly five full lobe pitches and is visually and mechanically equivalent to no tooth-index phase change.

If output-pin clearance holes must stay aligned to one shared output pin set, compensate the second disc's output_pin_phase by subtracting the same body phase before rotating the finished disc body.

Parameters

n_lobes

• Type: int
• Description: Number of cycloidal lobes. The matching fixed pin ring has

n_lobes + 1 pins and gives a single-stage ``n_lobes

• Description: 1`` reduction.

ring_pin_pitch_radius

• Type: float
• Description: Radius of the fixed ring pin centers in mm.

roller_radius

• Type: float
• Description: Radius of the fixed ring pins or rollers used to offset the profile.

eccentricity

• Type: float
• Description: Input crank eccentricity in mm.

gear_height

• Type: float, default 6.0
• Description: Disc thickness / extrusion height along Z in mm.

bore_radius

• Type: float, default 0.0
• Description: Optional central bore radius. Zero leaves the disc unbored.

output_pin_count

• Type: int, default 0
• Description: Optional number of circular output-pin clearance holes.

output_pin_pitch_radius

• Type: float, default 0.0
• Description: Radius of the output-pin clearance hole centers in mm.

output_pin_clearance_radius

• Type: float, default 0.0
• Description: Radius of each output-pin clearance hole in mm.

output_pin_phase

• Type: float, default 0.0
• Description: Angular phase of the first output-pin clearance hole in degrees, in the unrotated disc's local frame. When a finished disc is rotated to create a tooth-index phase in a twin-disc stack, subtract that same rotation from output_pin_phase if the clearance holes should remain aligned to the same global output pins.

sample_count_per_lobe

• Type: int, default 33
• Description: Number of analytic samples fitted into each lobe B-spline segment.

spline_tolerance

• Type: float, default 0.005
• Description: Cubic B-spline fit tolerance in mm.

max_control_points

• Type: int, default 20
• Description: Maximum poles allowed for each fitted lobe segment.