Powershift Mechanical & Electronic Components Flashcards
What are the 2 general categories of powershift trans applications
Cycling
Hauling
What are 2 general categories of powershift trans designs
Planetary
Countershaft
Powershift
Speed and direction changes made solely by operator
Automatic
Makes speed changes are made independent from operator. all operator chooses is reverse or top gear
Cycling application
Trans has an equal # of forward and reverse gears, commonly used is machines that do repeated back and fourth movements
Hauling application
Commonly use an automatic transmission. When a machines work is usually loading a one place and driving to another location
Cycling trans clutches
Cycling trans usually the same clutches in F and R
Differential planetary set
A simple planetary set with three rotating members which can have dual inputs and a single output
Dual input planetary
The Carrier speed will always be somewhere between the speed on the sun gear and the internal gear
Tooth speed carrier rotation
Carrier will rotate the direction of the input gear with the highest tooth speed
Tooth speed
Refers to the number of gear teeth that pass by a given point in a given period of time, measured in teeth per second (t/s)
Clutch discs
Steel discs that have a friction material bonded onto both surfaces of the disc. Use sintered bronze, or composite materials
Have ridges in discs for lubrication called lands
Clutch plates
Located between every pair of clutch discs
Usually have tangs on outside to lock to case housing
Clutch pistons
Lip type seal, o-ring and teflon seals are used to seal.
Lip type is more commonly used in automatic for full sealing, teflon can be used in big powershift where some leakage can be handled
The major advantage of a powershift or auto trans over a manual trans is
Power flow is not interrupted when shifts are made
