Gear 2 Flashcards
What is a gear train?
A power transmission system consisting of gears.
What is a simple gear train?
Each shaft carries only one gear; idler gears affect direction but not gear ratio.
What is a compound gear train?
At least one shaft carries two gears mounted concentrically, enabling larger gear ratios.
How is gear ratio calculated in simple gear trains?
Z = ω_in/ω_out = product of teeth on driving gears / product of teeth on driven gears.
What is a reverted gear train?
A compound train where input and output shafts are co-axial; center distances are equal.
What is the velocity ratio of a compound train?
Z = (NA·NC·NE) / (NB·ND·NF) for gear sets A-F on appropriate shafts.
What is the general gear ratio equation for planetary trains?
Z = (ωS - ωA) / (ωR - ωA) = -NR/NS
What are the three configurations of planetary trains?
- Fixed arm, 2. Fixed ring, 3. Fixed sun.
What happens when the arm is fixed in a planetary train?
Sun drives, ring is output in opposite direction at reduced speed.
What happens when the ring is fixed in a planetary train?
Sun drives, arm is output in same direction at reduced speed.
What happens when the sun is fixed in a planetary train?
Arm drives, ring is output in same direction at increased speed.
What is the advantage of planetary trains?
Compact, coaxial input/output, high torque transmission, used in autos and wind turbines.
What is the basic equation for a differential unit?
ω_arm = (ω1 + ω2) / 2
What is the main function of a differential unit?
Splits power to drive wheels and accommodates speed difference when turning.
What is the gear ratio equation of the Nissan Leaf gearbox?
Z = N2/N1 · N4/N3, using the compound train format.
What is a typical gear ratio for wind turbine gearboxes?
Roughly 1:60 to 1:100, converting low-speed, high-torque to high-speed, low-torque.
What is a key requirement in reverted trains?
Center distances of both gear pairs must be equal.
How many degrees of freedom does a planetary gear train have?
Two degrees of freedom.
What are idler gears used for in simple trains?
Change direction of rotation without affecting velocity ratio.
True or False: The Nissan Leaf gearbox is a compound gear train.
True
