3D Printed Planetary Gear for a Stepper Motor: Difference between revisions
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=Herringbone Version= | |||
*Source with great explanation of planetary gears - [https://0x7d.com/2014/41-gearbox-for-nema-17-stepper-motors/] | *Source with great explanation of planetary gears - [https://0x7d.com/2014/41-gearbox-for-nema-17-stepper-motors/] | ||
:*In this example, bearings should be added to planet gears to make the output shaft not wear out | :*In this example, bearings should be added to planet gears to make the output shaft not wear out | ||
| Line 6: | Line 8: | ||
*This is good for a geared down extruder for 3 mm filament. | *This is good for a geared down extruder for 3 mm filament. | ||
*This may be applicable to vehicle geardown with rubber-on-plastic drive for heavy duty applications up to 1000 lb drive for solar slow traction vehicles | *This may be applicable to vehicle geardown with rubber-on-plastic drive for heavy duty applications up to 1000 lb drive for solar slow traction vehicles | ||
*Modification: | |||
:*add bearings to planet gears | |||
:*add a cover with bearing. Planet gears serve as second bearing support point, but a double bearing in cover would release pressure from plastic gears. Because of short profile, we can add double bearing in cover to get lifetime >>1000 hours for extruder geardown applications | |||
:*Use hobbed bolt as the integrated shaft | |||
=Straight Gear Version= | |||
*This one has bearings, so it appears to be usable as is. No herringbone gears, though. - [https://www.thingiverse.com/thing:8460] | |||
*May need to increase cover plate and double up shaft bearing to address radial thrust in filament drive application. | |||
*Easy fix, outside of getting bolt lengths correct. | |||
*Disadvantage - there will.be wear as axial thrust is not addressed without herringbone design. | |||
=Why?= | =Why Herringbone?= | ||
*Note that | *Note that herringbone gears eliminate the need for a thrust bearing. That is a great point of size.plification when using planetary gears. | ||
*"Here is a design for a low-profile (18mm) stackable gearbox that fits onto a standard NEMA 17 stepper motor. The gearing ratio of 4:1 allows for increased torque and positional accuracy from the motor. Herringbone gears are used to provide smooth power transmission from the stepper motor while eliminating the need for thrust bearings. A flat rotating output platform is also provided to allow for easy mounting of attachments. More details along with a step-by-step guide to designing gears for 3D printing in Autodesk Inventor is provided below." | *"Here is a design for a low-profile (18mm) stackable gearbox that fits onto a standard NEMA 17 stepper motor. The gearing ratio of 4:1 allows for increased torque and positional accuracy from the motor. Herringbone gears are used to provide smooth power transmission from the stepper motor while eliminating the need for thrust bearings. A flat rotating output platform is also provided to allow for easy mounting of attachments. More details along with a step-by-step guide to designing gears for 3D printing in Autodesk Inventor is provided below." | ||
Latest revision as of 03:07, 7 May 2019
Herringbone Version
- Source with great explanation of planetary gears - [1]
- In this example, bearings should be added to planet gears to make the output shaft not wear out
- Thus, this is not a turnkey solution for practical applications. Design must be modified.
- This design appears to be completely stackable. 4x per stage gets you good geardown. Successive stages should be enlarged to handle higher torque.
- This is good for a geared down extruder for 3 mm filament.
- This may be applicable to vehicle geardown with rubber-on-plastic drive for heavy duty applications up to 1000 lb drive for solar slow traction vehicles
- Modification:
- add bearings to planet gears
- add a cover with bearing. Planet gears serve as second bearing support point, but a double bearing in cover would release pressure from plastic gears. Because of short profile, we can add double bearing in cover to get lifetime >>1000 hours for extruder geardown applications
- Use hobbed bolt as the integrated shaft
Straight Gear Version
- This one has bearings, so it appears to be usable as is. No herringbone gears, though. - [2]
- May need to increase cover plate and double up shaft bearing to address radial thrust in filament drive application.
- Easy fix, outside of getting bolt lengths correct.
- Disadvantage - there will.be wear as axial thrust is not addressed without herringbone design.
Why Herringbone?
- Note that herringbone gears eliminate the need for a thrust bearing. That is a great point of size.plification when using planetary gears.
- "Here is a design for a low-profile (18mm) stackable gearbox that fits onto a standard NEMA 17 stepper motor. The gearing ratio of 4:1 allows for increased torque and positional accuracy from the motor. Herringbone gears are used to provide smooth power transmission from the stepper motor while eliminating the need for thrust bearings. A flat rotating output platform is also provided to allow for easy mounting of attachments. More details along with a step-by-step guide to designing gears for 3D printing in Autodesk Inventor is provided below."