Actuator Fundementals

Question 1

Telescoping single acting cylinder

Answer 1

• Largest section moves first
• Only be used when load never goes over centre
• Oil generally comes in rod as mounted upside down compared to highway

Question 2

Cylinder seals may consist of

Answer 2

Leather
Polyurethane
Nitrile
Viton

Question 3

What are wipers used for

Answer 3

Prevent contamination from entering cylinder when rod is retracted

Question 4

Telescoping double acting cylinder

Answer 4

Has 2 ports

High pressure seals facing both ways inside

Question 5

Piston relief valve

Answer 5

Are small poppets that are held closed when high pressure oil is applied to move the rod, when the rod bottoms the poppets are forced opened allowing oil to flow to reservoir limiting pressure

Question 6

Cylinder cushion

Answer 6

Used to slow down the rod as it approaches end of travel

Meter the oil leaving the cylinder to slow its speed

Question 7

Quick drop valve

Answer 7

Used in regeneration
Allow oil for the rod end of cylinder to enter the base end a device is being lowered to speed up drop time.
Used on dozer blades and scraper bowls

Question 8

Regeneration

Answer 8

The process of using oil that is being returned to tank from the rod end of cylinder to help fill the base end and allow blade to drop to ground faster

Question 9

Speed of a motor is dependent on what

Answer 9

Inlet flow rate

Motor capacity

Question 10

Amount of torque generated by motor is determined by what

Answer 10

Motor displacement

Motor inlet pressure

Question 11

Gerollor and gerotor motors are used where

Answer 11

High torque, low speed operation

Question 12

Gerotor

Answer 12

Cam ring is held stationary

Spool and gear are mounted together

Question 13

What is the purpose of the roller inserts in a geroller motor

Answer 13

Provide better wear characteristics

Reduced internal resistance

Question 14

What is common swash plate angle in a piston pump

Answer 14

6.5 degrees

19 degrees

Question 15

How can you tell axial motor from pump pressure plate

Answer 15

Pumps have up to 2 fishtails
Reversible motors have 4 fishtails
Inlet may not be re-enforced on pump

Question 16

Why is axial piston shoe balanced

Answer 16

So as not to mill the shoe

Question 17

2 speed motor are normally in what position

Answer 17

Max torque

Question 18

What motors are normally in the max speed posistion

Answer 18

Fully pressure compensated motor

Question 19

Crankshaft type radial piston motor

Answer 19

The pistons do not rotate, only move up and down

Spool sends oil to top of piston and pushes piston down on side of crank

Question 20

Cam type radial piston motor

Answer 20

Pistons rotate with manifold
Cam is held stationary
High torque motor