Level D Basics – 1/5

Welcome to your Level D Basic, 1 of 5

1. What are the main elements of tribology?

Chemistry, physics, mathematics

Mechanical engineering, lubricant technology, chemical technology

Roller bearings, plain bearings, axial bearings

Friction, wear, lubrication

2. What is shown by the Stribeck diagram?

Type of material and lubricant used

Support surface of the friction partners and their relative speed

Load and efficiency

Friction coefficient and sliding speed

3. Which main three friction conditions are defined in a tribological system?

Friction conditions are not defined in a tribological system

Adhesive friction, gas layer friction, lubricating grease resistance

Rolling friction, sliding friction

Boundary friction, mixed friction, hydrodynamic friction

4. What is the unit for the kinematic viscosity of lubricating oils?

mm/s²

mm²/s

v/mms

v=s/t

5. What contributes to an efficiency loss in the tribological system?

Lubrication and efficiency

Lubrication and surface roughness

Friction

Material and shape properties

6. What is friction?

A physico-chemical process improving the efficiency of the moving parts

Resistance to a relative motion

Friction means wear

Friction is just the force to be applied if lubricants are sheared by movement.

7. Which type of friction reduces the efficiency in case of hydrodynamic lubrication?

Boundary friction only

Flow resistance of the lubricant

Rolling friction of roller bearings

Mixed friction

8. Where in a moving system can minimum frictional resistance be expected?

Always in boundary friction

At the transition from mixed to hydrodynamic friction

In rolling friction only

Can only be determined if load is <500 Newton

9. Why are additives used in lubricants?

To improve the base oil properties

To modify the lubricant properties

To improve the pumpability of the lubricant

To change and improve the properties of the lubricant

10. What is the function of EP and AW additives?

These additives neutralize particles that are not inherent to the lubricant

They are used in order to improve the low-temperature behavior

Protection of the material against damage, e.g. against scuffing in the boundary friction area

Protection of the material against corrosion

11. How does graphite work?

It is structurally effective

It is physically effective

It is chemically effective

It is reactive

12. Why are thickeners added to lubricating greases?

To achieve better adhesion properties of the lubricants

So that reaction layers are built up on the surfaces of the friction partners

To improve the lubricating properties of the oils used

They are to prevent the base fluids from flowing off

13. Which of the thickeners listed below is of organic origin?

None of the below

Polyurea

Bentonite

Lithium

14. What is the designation for a gear oil?

HLP 32

CLP 460

KP2K-40

VDL 100

15. What does „2” signify in the designation KP2K-40 as per DIN 51502?

The minimum shelf life of the lubricant is two years

The base oil viscosity is at least 2x100mm²/s

The thickener share is 20%

The consistency of the lubricant as per NLGI

16. Which is the ideal lubrication condition in a bearing?

Hydrostatic lubrication

Hydrodynamic lubrication

Boundary lubrication

Solid body lubrication

17. What is the main difference between the lubrication of gearings and bearings?

The lubrication of gearings is discontinous

The lubrication of gearings is continuous

The viscosity of the lubricant does not have a considerable effect on hydrodynamics

Gearings must always be lubricated with oil

18. The development of hydrodynamic lubrication in gear drives is subject to …

the module of the tooth flanks

the material combination of the tooth flanks

the sliding speed of the gear combinations

the gear transmission ratio

19. What is the formula to easily calculate the module?

Tooth width divided by tooth height

Number of teeth divided by pitch diameter

Pitch diameter divided by number of teeth

Tip diameter divided by tooth height

20. What is not a wear type and mechanism in a bearing or a gear?

Adhesion

Abrasion

Viscosity loss

Material fatigue

21. What are the components of a plain bearing?

Raceway, rolling elements, cage, lubricant, seal

Shaft, key, gear, lubricant, seal

Bearing shell, shaft, bearing seat, lubricant, sealing

Not applicable

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