mechadense
Conical_Ravigneaux_Sketch
Afterthought:
A 90° version like the concrete sketch here won't work due to symmetry around the plane doung though the center marked with "!!".
Other angles should work though.
Here's one with 45°:
★★★★★
Here is an idea for:
A highly 3D printable high ratio mechanical transmission based on the Ravigneaux planetary gearset
( en.wikipedia.org/wiki/Ravigneaux_planetary_gearset ).
Unlike a typical Ravingeaux gearset the planets axes are turned radially outwards thereby becoming conical rollers in what is kind of an exotic conical roller gear bearing configuration.
By choosing the alternate transmission configuration where the rings are connected rather than the suns, the morphed to corresponding conical configuration is now of such topology, that the output ring can clamped by a mirrored copy of the whole assembly. (Check the sketch to understand this.)
For assembly the idea is that
one single screw through the central axial screw suffices to
★ (1) hold together the whole assembly.
★ (2) fine adjust pre-tenstion in BOTH force and stiffness.
The herringbone profile is what prevents sideways-roller-slip-out despite axial compression. The herringbone profile might need to be rounded and made into an S shape for smooth running.
A shoutout for cycloid toothing:
In general choosing a full-profile-cycloid-toothing might be an excellent idea here with all the gears being pushed together (to zero backlash) by fine adjustable pre-tension.
Cycloid profiles are beneficial for smooth running.
None of the known cycloid weaknesses including:
★ precise inter axial distance requirement
★ difficult manufacturability
★ wavy torque and axial load due to varying pressure angle
apply here.
The clamping screw:
The screw could be be 3D printed too.
(see FDM-screw library below)
★ pre-tension stiffness could be adjusted by
a 3D printed rubber washer.
★ pre-tension force could be reliably kept by a special 3D printed clip lock for the nut on the screw. (I have something special in mind.)
www.thingiverse.com/thing:4836281
github.com/mechadense/scad-lib-FDMscrews
How a motor could eventually be integerated is highly dependent on the motors geometry. It would obfuscate the conceptual sketch here.
PS: The same "clamped conical roller gear bearing" idea could be used for mere passive hinges.
PPS: Notes to myself about here needed OpenSCAD stuff:
★ Generalize my periodic table of gear bearings to conical
www.thingiverse.com/thing:488993/makes
★ continue generalized cycloid gear library (hypoid)
★ finish screw arresting clip for flatscrews
Conical_Ravigneaux_Sketch
Afterthought:
A 90° version like the concrete sketch here won't work due to symmetry around the plane doung though the center marked with "!!".
Other angles should work though.
Here's one with 45°:
★★★★★
Here is an idea for:
A highly 3D printable high ratio mechanical transmission based on the Ravigneaux planetary gearset
( en.wikipedia.org/wiki/Ravigneaux_planetary_gearset ).
Unlike a typical Ravingeaux gearset the planets axes are turned radially outwards thereby becoming conical rollers in what is kind of an exotic conical roller gear bearing configuration.
By choosing the alternate transmission configuration where the rings are connected rather than the suns, the morphed to corresponding conical configuration is now of such topology, that the output ring can clamped by a mirrored copy of the whole assembly. (Check the sketch to understand this.)
For assembly the idea is that
one single screw through the central axial screw suffices to
★ (1) hold together the whole assembly.
★ (2) fine adjust pre-tenstion in BOTH force and stiffness.
The herringbone profile is what prevents sideways-roller-slip-out despite axial compression. The herringbone profile might need to be rounded and made into an S shape for smooth running.
A shoutout for cycloid toothing:
In general choosing a full-profile-cycloid-toothing might be an excellent idea here with all the gears being pushed together (to zero backlash) by fine adjustable pre-tension.
Cycloid profiles are beneficial for smooth running.
None of the known cycloid weaknesses including:
★ precise inter axial distance requirement
★ difficult manufacturability
★ wavy torque and axial load due to varying pressure angle
apply here.
The clamping screw:
The screw could be be 3D printed too.
(see FDM-screw library below)
★ pre-tension stiffness could be adjusted by
a 3D printed rubber washer.
★ pre-tension force could be reliably kept by a special 3D printed clip lock for the nut on the screw. (I have something special in mind.)
www.thingiverse.com/thing:4836281
github.com/mechadense/scad-lib-FDMscrews
How a motor could eventually be integerated is highly dependent on the motors geometry. It would obfuscate the conceptual sketch here.
PS: The same "clamped conical roller gear bearing" idea could be used for mere passive hinges.
PPS: Notes to myself about here needed OpenSCAD stuff:
★ Generalize my periodic table of gear bearings to conical
www.thingiverse.com/thing:488993/makes
★ continue generalized cycloid gear library (hypoid)
★ finish screw arresting clip for flatscrews