Powershift and Automatic Transmission Mechanical and Electronic Components

Question 1

The function of the transmission in a piece of mobile heavy equipment is to modify the engine power that propels the machine. The transmission allows the operator to _______ vehicle speed and _________ torque under conditions of heavy load. Speed can be __________ and torque ____________ when load is light.

Answer 1

decrease, increase, increased, decreased

Question 2

The major advantage of using powershift or automatic transmission rather than a manual transmission is that ________________________________________.

Answer 2

power flow is not interrupted when shifts are made.

Question 3

Powershift transmissions are most often used in equipment that is intended for ___________, while automatic transmissions are more common in ____________.

Answer 3

cycling applications, hauling applications.

Question 4

The planetary gear set component that meshes with the sun and internal gear is called the planet carrier.
True
False

Answer 4

False, planet pinions

Question 5

Which component is being held reactionary when a planetary gear is set is producing its deepest speed reduction?

a. The sun gear.
b. The planet pinions.
c. The carrier.
d. The internal gear.

Answer 5

d. The internal gear.

Question 6

Identify which of the following planetary gear set components are the input, output, and reactionary member when the output of the gear set is a reverse reduction.

a. sun gear ______________________
b. internal gear ___________________
c. planet carrier___________________

Answer 6

a. input member
b. output member
c. reactionary member.

Question 7

Two methods of achieving direct drive from a single planetary gear set are:

Answer 7

Locking two members of the sun gear set together.

Driving two members of the gear set at the same speed.

Question 8

A single planetary gear set has variable speed inputs on both its sun and internal gears. select the term from the right columns that best describes the output of each of the conditions in the left column.
reduction
neutral
direct drive
reverse
a. Internal gear rotating forward and sun gear rotating in reverse at the same tooth speed as the internal gear. _______________.
b. Both internal and sun gear rotating forward at the same tooth seed. ______________
c. Internal gear rotating in reverse at much higher tooth speed than sun gear is rotating forward. ___________
d. Internal gear and sun gear rotating forward at equal rpm. ________

Answer 8

neutral
reduction
reverse
direct drive

Question 9

State two functions of the grooves cut in the face of the friction material on the clutch discs.

a. _______________
b. _______________

Answer 9

a. carry oil to lubricate the discs when the clutch is disengaged.
b. allow oil to be squeezed out when the clutch is applied.

Question 10

Countershaft type powershift and automatic transmissions transmit power by locking spur gears to a countershaft using a hydraulically applied clutch.
True
False

Answer 10

True

Question 11

Many heavy equipment transmissions provide a place to couple auxiliary components such as hydraulic pumps. These devices are known as:

a. torque converters.
b. power take offs.
c. output shafts.
d. input shafts.

Answer 11

b. power take offs.

Question 12

A powershift differs from an automatic transmission in that shifts are made solely at the digression of the operator.
True
False

Answer 12

True

Question 13

List four advantages that planetary gear sets have over spur gear sets.

Answer 13

a. The gears used in a planetary gear set are constantly is mesh therefore there is no grinding or missed shifts when changing gears.
b. A smaller more compact planetary gear set is capable of transmitting the same amount of torque as a larger spur gear set because gear tooth loading is spread out.
c. smaller bearings and thrust washers can be used because radial ad axial thrust loads are offset in a planetary gear set.
d. Planetary gear sets are extremely versatile in that they are capable of providing a great many combinations of speeds and directions when multiple sets are used.

Question 14

A gear ratio that is expressed .33:1 means that:

a. input torque will be multiplied 3 times through the gear set.
b. the output will turn .33 revolutions when the input is rotated 1 revolution.
c. the input must be rotated .33 revolutions to produce 1 output revolution.
d. the gear set is producing a gear reduction.

Answer 14

c. the input must be rotated .33 revolutions to produce 1 output revolution.

Question 15

Which component of a single planetary gear set is the input member when the output member is in overdrive and turning in the same direction as the input member.

a. the sun gear
b. the planet pinions
c. the carrier
d. the internal gear

Answer 15

c. the carrier

Question 16

Two methods of achieving neutral from a single planetary gear set are:

a. ______________
b. ______________

Answer 16

a. no held or reactionary member.

b. no input power to the gear set.

Question 17

Two planetary gear sets are arranged as a multiple combination. Input power is supplied to the sun gear of the first set and its internal gear is held. The output of the first gear set feeds the sun gear of the second set. Which of the statements below correctly describes the output of the combination of the two gear sets if the carrier of the second is held?

a. a double reduction in the reverse direction
b. a double reduction in the forward direction
c. a double overdrive in the forward direction
d. a single reduction in the reverse direction

Answer 17

a. a double reduction in the reverse direction

Question 18

The clutches used in planetary type transmissions are:

a. multiple disc type.
b. applied with oil pressure.
c. spring released.
d. all of the above responses are correct.

Answer 18

d. all of the above.

Question 19

Countershaft type transmissions are not as compact as planetary type units because:

Answer 19

Shafts and bearings of a countershaft transmission must be larger to handle increased thrust loads.