190303gB

Question 1

what does a dual path hydrostatic system to control direction and speed of machines tracks consist of?

Answer 1

2 closed circuit hydrostatic drive systems that control speed and direction of each track

Question 2

what kind of pumps are used on a hydrostatic steering system?

Answer 2

variable displacement reversible pumps

Question 3

what kind of motors are used in a hydrostatic steering system?

Answer 3

variable displacement motors, mounted directly to the final drives

Question 4

how can the operator vary track speed?

Answer 4

vary pump and motor displacement

Question 5

what happens when one of the hydrostatic pumps is placed in neutral and the other still spins?

Answer 5

machine will perform a pivot turn

Question 6

how can the machine counter-rotate?

Answer 6

rotate one track in forward direction and the other track in the reverse direction

Question 7

advantages of a hydrostatic steering system?

Answer 7

1. power is applied to both tracks when tractor is being turned
2. infinitely variable track speed and counter rotation
3. machine ground speed can be adjusted for optimum traction with infinite speed control

Question 8

function of the charge pump?

Answer 8

keep closed circuit filled with oil so pump will not cavitate
supercharge the pump
keep system pressurized
provide lube

Question 9

what does the neutral charge relief valve do?

Answer 9

limit pressure in charge circuit when hydrostatic pump is in neutral

Question 10

where does the neutral charge relief valve oil dump to?

Answer 10

the hydrostatic pump case for pump cooling and lube

Question 11

where is a charge filter located?

Answer 11

outlet line from charge pump, filters shit out before it can get to important steering system

Question 12

what does the internal pump swashplate control?

Answer 12

pump displacement, flow direction

Question 13

what controls the position of the pump swashplate?

Answer 13

pressure control pilot and pump displacement control valve

Question 14

what happens when the swashplate is in neutral on the pump?

Answer 14

no piston stroke, no oil to motor.

Question 15

what style are the hydrostatic motors?

Answer 15

bent axis variable displacement

Question 16

how is the displacement of the motor controlled?

Answer 16

by servo pistons, change angle from 32” to 6”

Question 17

greater angle of the cylinder block the greater the motor _______

Answer 17

displacement

Question 18

as motor displacement increases, the speed of the output shaft ____ but torque generating capability _______

Answer 18

decreases, increases

Question 19

what helps to charge the circuit when the hydrostatic pump is in neutral?

Answer 19

check valves

Question 20

why are there 2 high pressure relief valves?

Answer 20

to limit pressure in both forward and reverse directions

Question 21

what is the flushing valve for?

Answer 21

for filtering oil so that cool oil can be brought in

Question 22

how is the flushing valve shifted open?

Answer 22

shifted open by high side, dumps from low side

Question 23

what side does the operating charge pressure relief valve limit pressure on?

Answer 23

the low pressure side

Question 24

what does the engine speed control sensor do?

Answer 24

send voltage signal to ecu indicating position of engine throttle

Question 25

what does the left/right steer sensor do?

Answer 25

sends variable voltage signal to ecu indicating direction operator wishes to turn

Question 26

what does the steering differential have?

Answer 26

power input from power shift tranny, determines ground speed and direction
power input from hyd steer motor, right and left turns,
2 power outputs, one to each final drive

Question 27

the direction of rotation of the steering motor determines the direction of the turn, while the speed of the motor and speed of the tractor determines the _______ of the turn

Answer 27

radius

Question 28

what is the function of the steering system hyd components?

Answer 28

control speed and direction of steering motor, controls direction and rate of machine turns

Question 29

what are the two methods used to control steering motor speed and direction?

Answer 29

proportional dcv
closed circuit hydrostatic drive