303C: Powershift & Automatic Transmission Mech/Elec. Components Flashcards
What is gear ratio?
Refers to the number of revolutions the input gear makes to complete one revolution of the output gear.
Ratio = Driven/Drive
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What is the formula for gear ratio?
Gear Ratio = Driven/Drive
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How is 1st speed reduction acheived in a planetary gear set?
Input: Sun
Output: Carrier
Reactionary: Internal
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How is 2nd speed reduction acheived in a planetary gear set?
Input: Internal
Output: Carrier
Reactionary: Sun
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How is 1st speed overdrive acheived in a planetary gear set?
Input: Carrier
Output: Internal
Reactionary: Sun
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How is 2nd speed overdrive achieved in a planetary gear set?
Input: Carrier
Output: Sun
Reactionary: Ring
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In a planetary gear set if the carrier is held, you will always get what condition?
Reverse
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How is 1st speed reverse achevied in a planetary gear set?
Input: Sun
Output: Internal
Reactionary: Carrier
A reduction
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How is 2nd speed reverse achieved in a planetary gear set?
Input: Internal
Output: Sun
Reactionary: Carrier
An Overdrive
What are three methodes of acheving neutral in a planetary gear set?
1) No held member
2) No input
3) Sun and internal gear driven in opposite directions at the same tooth speed
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How is direct drive acheived in a planetary gear set?
- Locking two members together
- Driving two members at the same speed
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What are the two basic design types of powershift and automatic transmissions?
- Planetary
- Countershaft
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A highway use gravel truck is an example of a machine used in a cycling type application. (T/F)
False
Would use an automatic transmission for its hauling aplication.
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A scraper is typically used in a hauling application. (T/F)
True
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What are the two type of clutch discs used in transmission clutch assemblies?
Clutch discs - Friction material
Clutch plates - Reaction surface for disks
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What is the purpose of the grooves on the face of clutch disc’s friction material?
Lands
- Carry oil to lube the discs when disengaged
- Allow oil to be squeezed out when clutch is applied
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How are the transmission clutch packs applied?
Hydraulically actuated
Spring released
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Reverse gear in a countershaft transmission is possible through two main components:
- Idler gear on countershaft
- Reverse clutch activation
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Gear selection in a countershaft transmission is engaged by:
Drilled oil passages that hydraulically apply clutch discs
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Many heavy equipment transmissions provide a place to couple auxiliary components such as hydraulic pumps. This drive is known as:
Power takeoff
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What is a major advantage of using powershift or automatic transmissions rather than a manual transmission?
Power flow is not interrupted when shifts are made
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A powershift differs from an automatic transmission in that shifts are made solely at the discretion of the operator. (T/F)
True
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The planetary gear set component that meshes with the sun and internal gear is called the planet carrier. (T/F)
False
The planet pinions mesh with the sun and internal gear.
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With a gear ratio of 0.33:1, how many times must the input gear rotate for the output gear to complete one revolution?
Input must be rotated 0.33 revolutions to produce one output revolution
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Which component is being held reactionary when a planetary gear set is producing its deepest speed reduction?
Internal gear
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Which component of a single planetary gear set is the input member when the output member is in overdrive?
Carrier
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Countershaft type powershift and automatic transmissions transmit power by locking spur gears to a countershaft using a hydraulically applied clutch. (T/F)
True
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Why are countshaft transmissions not as compact as planetery type units?
Thrust loads are not balanced which requires larger shafts and bearings
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How are powershift transmissions different than an automatic transmission?
Powershift: Speed changes done soley at the discretion of the operator
Automatic: Speed changes done independent of any action from the operator
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What type of transmissions are most often used in cycling applications?
Powershift
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What type of transmissions are most often used in hauling applicaitons?
Automatic
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When a clockwise rotating external gear is meshed with an internal gear, what direction does the internal gear rotate?
Clockwise
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What has the greater reduction: 1st speed reduction or 2nd speed reduction
1st speed reduction
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What has the greater overdrive: 1st speed overdrive or 2nd speed overdrive
2nd speed overdrive
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How many planetaries are used in differential steering on a CAT dozer?
Three
- Steer
- Drive
- Equalizing
https://www.scribd.com/document/576627656/Cat-Dozer-Differential-Steering
