24-03-2012, 02:36 PM
Teaching Gear Theory to Students
2005CON_Teaching_Gear_Theory_to_Students.ppt (Size: 1.5 MB / Downloads: 205)
What We Will Talk About
Discussion of gears especially for FLL
Will have parallel topic for FIRST
For LEGO® gears, will use LDraw names
Will have a demo area here on the gears
Basic Gear Types in LEGO
In Sets Other than RIS 2.0 (still available)
Bevel Gear (20t)
Double Bevel Gears (12t, 20t, 36t not pictured)
Turntable (56t)
Old Differential Gear (24t on casing)
Technic Gear 16t with Clutch
Essential Terminology
Driver – gear with applied force
Follower – gear doing useful work
Idler – gear turned by driver & turns follower
Gear Train – many gears in a row
Geared Up – large driver, small follower to speed gear train up.
Geared Down – small driver, large follower to increase torque (turning force)
Compound gears – combination of gears and axles where one axle has 2 gears often of different sizes.
What happens with improper mesh?
When 2 gears are meshed, there is a certain amount of built in “play” between them called backlash.
When 2 gears are not meshed properly i.e. within specification you get too much backlash called slop OR too little backlash and they are jammed together and this creates friction.