Backstory
In the 2024 season CHAOS 131 experience some challenges related to our tilt mechanism. We machined the gear arcs and 3d-printed the pinions. The mechanism worked well until we failed to set it up correctly or a software development caused to to strip the teeth off the gear. It didn’t take long for us to recognize the pinions as disposable. I was inspired by this thread as a Lantern Pinion can be self-made in a way that can take a bunch more load on a simple CNC router without much Machining time.
I am happy to present:
Lantern Gear Generator
Lantern gear Generator has the ability to generate:
- Lantern Gears
- Lantern Ring Gears
- Lantern Racks
- Lantern Pin Wheels (Pinions)
The Generators use function driven curves to create the geometry to ensure high fidelity, smooth running geometry. To test this I created a 3D-printed toy (in the example folder) that uses bearings for the Pin Wheel. The motion is quite smooth.
There are 3 part studios in the main level that act as the core of the generator. I recommend deriving the parts in these into your part studio and modifying them based on the needs of your design. There are also 2 Assemblies that show how the Pin Wheels mesh with the geometry. These assemblies can be good to help you get going quickly, but are not really intended to be used in designs directly .
The generators allow you to specify:
- The number of “Teeth” or pins on the Pin wheel (Pinion Teeth)
- The number of Teeth on the Gear/Rack
- The Diametric Pitch of the mesh.
- Extra thickness on the Pin Wheel outside of the Pins themselves (PinWallThickness)
- The thickness of the Gear or Rack
- The thickness of the Pin Wheel (PinionPlateThickness).
- The Length of the Pins
- As well as the bore styles of the Gear and Pin Wheel
Some Helpful Tips:
- If you are going to CNC route these, the pin diameter needs to be larger than the endmill you plan on using to machine the teeth.
- I recommend ensuring the Diametral Pitch is large enough that the gear teeth are of a similar thickness to the pins.
- Lantern Gears can support pinions with fewer teeth than Involute spur gears as the pins are supported in shear and not cantilevered from the hub.
- Bearings and bushings can be used over shoulder bolts or pressed dowel pins to make a very smooth mesh.
- Onshape is not perfect at regenerating some geometry. If you run into a problem spot, you may be able to make a copy of the document (Please rename it or keep your version private) and use slightly different techniques to get the results you need. The modeling techniques used here are selected to be robust through most regeneration events, but there are simper modeling techniques that can handle a single configuration better.
I’m happy to answer any questions the community has!