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Editors:

Marcin Jakubowski

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Graphic Design:

Jean-Baptiste Vervaeck

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Version:

Date:

Shafts and Bearings

v19.05

First Edition

Open Source Ecology Design Guide Series

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Shafts and Bearings - Table of Contents 1

Summary – Different ways to implement shafts and linear bearings. Bushings for Universal Axis, bearings for rotors; mounting of wheels. 3D printed linear bearings. On-wheel or on-shaft bearings via Planetary Gears or 3D Printed Bearings. 2 point mounting; rating of shafts for axial and radial load. Supported and unsupported shafts. Planetary herringbone for axial load management. Planetary gears as wheel-integrated bearings. Air bearings. Flexible 3D printed bearings. Lubrication. PLastic vs metal. Linear bearing with cycling balls. Applications – whatever we build, it will move or rotate. It will have shafts and bearings, and we need to understand some basics about their design so that we can handle high loads and speeds.

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  1. About Shafts and Bearings
    1. Shafts and Bearings - what are they?
    2. The Ball Bearing makes the world turn round
    3. How it works - and why it works
  2. Modular shafts
    • Geometrical fit - hex, spline
  3. Design considerations
    • Shaft materials
    • Self-supported shafts
    • Non-supported shafts
    • Bearing materials - solid, ball, air, oil-embedded
    • Lubrication: applied, embeded, submerged, air
    • Bushings, bearings, linear rails, air bearings
    • Considerations for mounting wheels. Planetary gear mounting of wheels
    • Considerations for ounting other rotors: cutter, shredder, chain, fast, slow
    • Axial and radial load and load containment
    • Set screws, collars, keys, herringbone
    • Round, splined, D, square, hex shafts
    • Shaft capacity and deflection for different materials
    • Hollow and solid shafts - self-deflection considerations
      1. 1” shaft example vs ¾” pipe
    • Scales of design: 30 cm, 1m, 10 meter, 30 meter
      • Straightness at each scale
      • Deflection at each scale
      • Examples: 1” solid vs pipe, 2” solid vs pipe, 6” solid vs pipe

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Available Geometrical Shafts

Summary – Round does not hold. Use other geometry. 3D print the geometry. Good for 1000 lb force with 1” cross section belts

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  1. 1.5” hex is $25/ft from metal store and half of that for 1”

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Clamp Collar

Flanges

Bolt

Cut the collar in Half. Removes some material for a tighter fit.

Clamshell Method to Make a Clamping Shaft Collar

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Shafts and Bearings - Table of Contents 2

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  • Design considerations (continued)
    • Beam deflection - online calculators + FreeCAD
    • RPM and inertia
    • Designing large 3D printed bearings with circulating or recirculating balls
    • Other shafts:
      • Supported Linear Rails
      • Dovetails and
    • Shaft considerations for geardowns - torque requirements
  • Designing shaft systems
    • Applications:
      • Coupling motors to shafts and devices
      • Mounting wheels: models and lifesize.
      • Designing high load drill and saw shafts
      • Designing shafts for geardowns
      • Supported shafts for the large Universal Axis
      • Rails in air (universal axis) vs. high strength supported rail
      • Building an indexing head
      • Building turntable bearings
      • Large gantries - limits of Universal Axis and transition to Supported System
    • Calculations - performance and cost
    • Visual Bill of Materials
    • FreeCAD Part Libraries
    • Design checklist

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Shafts and Bearings - Table of Contents 3

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  • Building a shaft/bearing system
    • Tools and materials
    • Build techniques
      • 3D printing considerations - size, accuracy, and strengtth
      • No grooves or keyways - the quick-connect spline shaft
      • Grinding, fitting bearings, rust, lubrication
      • Blanchard grinding, surface gridings, and precision grinding
      • Welding couplers and their alignment - plug or lathe
      • 3D printing couplers
      • Alignment and runout
      • Solid vs flexible coupling: couplers, belts, chains, sprockets
      • Working with granite and air bearing shafts
    • Sample build: the Universal Rotor
    • Build checklist and quality control
    • Testing and data collection - measuring torque, speed, power., and stability
  • System Integration
    • Mounting motors
    • Mounting rotors
    • Safety - guards, protectors
    • Mounting encoders and feedback
    • Stacked or parallel shafts
    • Integration in a given machine: overall checklist

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Notes On Using this Guide

OSE work builds upon these great open source projects:

ABOUT: This is part of a design series on general machine design aimed at basic competency in the design of all 50 Global Village Construction Set machines.

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HOW TO USE: You can use a QR code reader to scan the bar codes to access content online.

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COLLABORATION: This is a collaborative effort. You are invited to help edit this guide. You can edit this document or make a copy, make your edits, and email us describing your proposed changes. To join our open source product development effort, join our Developer Team, or get hands-on experience in our Workshops. Email us at info@opensourceecology.org

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2.3.4 - 3D Printed Turntable Bearing

Subtitle

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Use magn