word doc assign

Question 1

list three main stores of pumps

Answer 1

vane , gear and piston

Question 2

what is required at the pump inlet in order for oil to flow into the inlet port?

Answer 2

a lower pressure than what is in the reservoir

Question 3

explain why hydraulic pumps are required to be positive displacement pumps

Answer 3

need positive seal between inlet and outlet. allows pump to maintain against back pressure at outlet port

Question 4

explain the difference between a pressure compensation and load sending in a pump, which is more efficient?

Answer 4

pressure sensing stops pumping at max pressure.

loadsensing stops at load + 200psi pressure

goal is to to stop flow when not needed ( load sensing does that at lower psi) ( more efficient )

Question 5

explain the difference between inline axial piston pump and a bent axis piston pump

Answer 5

swashplate vs bent axis . bent axis much stronger . in-line can have variable displacement automatically while bent axis is usually manually adjusted

Question 6

explain the difference between radial piston pump and rotary piston pump

Answer 6

radial = stationary pistons , rotary cam

rotary= rotating pistons, stationary cam

Question 7

explain the difference between a balanced vane pump and a unbalanced vane pump

Answer 7

unbalanced = round cam ( larger and requires bigger bearings )
balanced = elliptical cam

Question 8

what is the purpose of the intra-vane in a pump? in what type of pump would you find one?

Answer 8

increases loading pressure on vane allowing it to maintain contact with cam at high pressures , found on balanced vane pump

Question 9

explain the differences between an internal gear pump and an external gear pump?

Answer 9

internal = crescent seal

Question 10

explain the operation of a cylinder cushion

Answer 10

flow restrict or which cushions last bit of stroke