Gearing Principles Flashcards
Pitch line
The line dividing the gear tooth lengthwise
Gear tooth face
Upper portion of tooth
Gear tooth flank
Lower portion of tooth
Gear tooth toe
Smaller end of tooth
Gear tooth heel
Larger end of tooth
Gear tooth drive side
The convex side of tooth, push is against drive side
What it purpose of gear tooth root fillet
Give tooth strength and reduce the chances of cracking at tooth base
Gear tooth pitch circle
Diameter of gear when measured across pitch line
Gear tooth clearance
Space between the tip of one tooth and the root of the meshing teeth, helps to maintain a lubrication film.
Backlash
The space between to gear teeth in mesh
Non-hunting gear
Pinion teeth number divides equally into the number of teeth on the crown gear. Must be timed
Partial non-hunting
2 or 3 revolutions of crown must occur before back to starting point. Ratio will divide unequally completing in 1 or 2 decimals. Must be timed
Hunting design
Not timed. Every pinion tooth will touch every crown tooth.
Gear reduction
When a small gear drives a large gear. Speed will be decreased and torque will be increased.
Gear overdrive
When large gear drives a small gear. Speed will increase and torque will decrease
Straight cut spur gear
Tooth appears symmetrical, generate not end thrust. Cheap to manufacture, but are not as strong
Internal gears
Have teeth located on the inner perimeter of the gear. Can have a high load handling capability
Single helical gears
Teeth cut at angle to the shaft. Provides great strength and less noise. Angled meshing contact ensures that multiple teeth are involved in the transmission of torque. Create axial thrust loads.
Herringbone gears
Double helical gears. 2 helical gears attached together so that the axial thrust loads cancel each other out.
Hypoid gears
Centerline of the drive pinion shaft is below the centre of the crown gear. Has even more tooth contact then spiral bevel gear sets, increasing load handling capabilities.
Amboid gears
Centerline of the drive pinion shaft is above the centre of the crown gear. A before H = A above H
Reactionary member
The member of a planetary gear that is held stationary?
What are the 3 main gear components of the simple planetary gear set?
Sun gear
Ring gear / Internal gear
Planet pinions on carrier
Why do some angle gear sets need to be timed?
The gears are designed and lapped into a distinctive wear pattern from the factory, and need to maintain this relationship
