190303c powershift components Flashcards
A machine comes in, it has an external reservoir, the customer complaint is that the overheating warning for transmission light comes on when driving and the oil level is high when you check it, the oil doesn’t look contaminated, what is the most likely cause of this issue : operator claims he hasn’t put any new oil in it? pick the best answer and explain it:
A. overfilled transmission by customer
B. oil cooler (oil to coolant type) failure
C. scavenge pump failure
D. cracked hydraulic tank
C. hydraulic pump failure
C. Hydraulic pump failure, as the pump seal will usually be facing internally on the torque converter housing, it would allow the same type of oil to leak (or similar oil) into the converter, and the scavenge pump will pull oil into the transmission (as it supplies the lubrication and torque converter circuit, the pump is running separate hydraulics) from the torque converter housing causing a higher oil level in the transmission
What is the function of a transmission?
To provide speed changes, a reverse, a neutral, and a pto
What are the two types of transmissions and explain which each one is designed for
Automatic transmissions for hauling applications and powershift transmissions for cycling applications
What is the benefit of a powershift or automatic transmission?
allows operator to shift while under power or under load
Which transmission allows operator to control speed or shifting?
powershift transmission
What absorbs end thrust on planetary gear sets?
brass or steel thrust washers between the gear ends and the carrier
What are some benefits to planetary transmissions?
Smaller transmissions compared to countershaft transmissions, gears are always in constant mesh, many different combinations of speeds and directions can be used, versatility
how many different speed and direction combinations IN TOTAL can a planetary provide?
5 different, but in total 8 in theory
What are the conditions of every gear in a planetary gear when it is in first speed reduction
Sun gear input, carrier output, internal held
What are the conditions of every gear in a planetary gear when it is in second speed reduction
internal input, carrier output, sun held
What are the conditions of every gear in a planetary gear when it is first speed overdrive
carrier input, internal output, sun held
What are the conditions of every gear in a planetary gear when it is second overdrive
carrier input, sun output, internal held
What are the conditions of every gear in a planetary gear when it is reverse 1st speed
carrier held, sun input, internal output
What are the conditions of every gear in a planetary gear when it is reverse 2nd speed
carrier held, internal input, sun output
What are the conditions of every gear in a planetary gear when it is a neutral condition
when the is an output but no held members, no input to the gear set
What are the conditions of every gear in a planetary gear when it is direct drive
locking two members together, or driving two members of a gear set at the same speed (rpm), in the same direction
describe the inputs and outputs of the three different types of planetaries in terms of input output configurations
multiple planetary transmission: in on the sun, out on the internal gear, double input, in on the sun out on the carrier, double output: in on the sun out on the sun
What is tooth speed?
The number of gear teeth passing by a given point in a given period of time and is measured in teeth per second
what would a positive tooth speed forward, and negative tooth speed be as a condition in a planetary if the tooth speed were both of the same number?
neutral condition
would would a higher tooth speed on the internal gear compared to the input gear (sun gear): for example tooth speed of the sun gear is 4 tps, and internal is 8 tps
it would be considered a reduction
what would an equal rpm of the sun and internal gear if the tooth speed of the sun was lower, and the tooth speed of the internal was way higher and why
a direct drive, as they both are driving at equal rpm
internal gear rotating in reverse at a much higher tooth speed than the sun gear is rotating forward, what condition would the planetary be in?
reverse
What are the lands used for on clutch friction discs?
holding oil to the discs when not engaged, and squeezing the oil out when engaged
What is the purpose of a hole with a ball in a clutch piston?
a sort of dump valve, or orifice, could be also for modulation
what are holes in the sides of a rotating clutch housing for? and why?
release of oil for when the clutches are throwing oil off of them due to centrifugal force, other wise oil could build up inside the housing and create issues
what gearing configuration has all the gears moving at the same time?
countershaft gearing configurations
what type of clutches are normally in a transmission?
hydraulic applied, spring released of the rotating type
What types of clutches are there (there are 2)
fixed and rotating
Why are countershaft transmissions bigger?
thrust loads are not as balanced as in planetary types
