Search the Community
Showing results for tags 'friction'.
Found 2 results
-
Gearbox theory application - my attempts towards building an automatic gearbox for a car
TechnicBrickPower posted a topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
This video applies gearbox, torque, and gearing ratio theory to design a prototype 2 speed automatic gearbox. First I describe the main components of an automatic gearbox, namely a gearing ratio selector and a torque detector. The ideal gear switch over torque point is described in terms of the PF motor torque and speed operating point, as well as the ideal gear switching ratio for the 2nd gear of the automatic gearbox. A technique for creating the 2nd gear is described by either adding to a differential by engaging a gear, or by subtracting by disengaging the gear. Issues around torque friction making it difficult to disengage a gear are mitigated by speeding up the gear switching axle to reduce torque. A torque detection method is shown using a differential for torque detection and driving a rotary catch back to the gear selector to change gears. A strategy is shown to reduce the torque and power loss due to the torque detector by placing it on a secondary path from the main power path. Finally an actual implementation of a 2 speed automatic gearbox is demonstrated and tested using a configurable torque generation mechanism using a series of clutch gears. -
Making a Technic axle pin with friction
JGW3000 posted a topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
I have been frustrated with the looks of the garish blue axle pins with friction, especially when you see a bunch of blue circles on otherwise nice green/black/white/red panels and beams on the exterior surface of builds. You know the ones I am referring to - http://www.bricklink...tem.asp?P=43093 The black (and white) versions of 43093 are outrageously expensive in quantity, so unless someone makes a batch, its not an option I am thinking about using the light grey or tan "axle pin without friction ridges lengthwise", http://www.bricklink...Item.asp?P=3749, but in certain situations the friction is needed to maintain stiffness in the structure (black in this is also very pricey). Any thoughts on how to introduce "friction" or "stiction" into the pin end of the 3749 part, but without doing permanent damage to the part or the receptacle? I was thinking a bit of double stick tape may do the trick