1. Projekt Anglicky v odborných předmětech, CZ.1.07/1.3.09/04.0002
Anglicky v odborných předmětech "Support of teaching technical subjects in English“
Tutorial: Engineering technology
Topic: Friction transmission
Prepared by: Ing. Jaroslav Hábl
Projekt Anglicky v odborných předmětech, CZ.1.07/1.3.09/
je spolufinancován Evropským sociálním fondem a státním rozpočtem České republiky.

2. FRICTION TRANSMISSIONS

3. FRICTION TRANSMISSIONS
ADVANTAGES OF FRICTION TRANSMISSION
Quiet operation
It can have the function of coupling
Impacts are absorbed by slippage
Little distance of axis at contact gears

4. FRICTION TRANSMISSION
DISADVANTAGES OF FRICTION GEARS
High pressure on shafts and bearings
Unevenness of transmission rate
Even roll wearing – circularity disturbance

5. FRICTION TRANSMISSION
DISADVANTAGES OF FRICTION GEARS
High pressure to shafts and bearings
Volatility of gear ratio
Even roll wearing – circularity disturbance

6. FRICTION TRANSMISSION
Gear ratio
The rule for friction gears by slip effect is:
ψ = slip coeficient

7. FRICTION TRANSMISSION
Basic types of friction contact gears
a b c d e f
a) Outside gearing, b) inside gearing, c) outside gear with keyway, d) inside gear with keyway, e) conical bearing, f) gear with face wheels

8. FRICTION TRANSMISSION
MATERIALS OF FRICTION WHEELS
Quenched steel x quenched steel – higher pressure force enables higher load transmission,
Longer durability.
Rubber x steel or cast iron – gearing has quiet operation, it transmits cca 10x smaller loading.
Other materials x steel or cast iron – e.g. Fibre, plastics etc.
Non-metallic materials are mostly used as metallic wheels lining.

9. FRICTION TRANSMISSION
CONSTRUCTIONAL VERSION OF FRICTION WHEELS
a) Frontal with lining, b) frontal with layered leather, c) face cast iron wheels, d) face wheels with lining

10. FRICTION TRANSMISSION
CONSTRUCTIONAL VERSION OF FRICTION WHEELS
a) WHEEL WITH LINER, b) WHEEL WITH LEATHER LINING, c) IRON CONICAL WHEEL, d) FRICTION FACE WHEEL WITH DIVIDED THREAD

11. FRICTION TRANSMISSION
Constructional version of friction wheels
a) Frontal with lining, b) frontal with layered leather, c) face cast iron wheel, d) face wheel with lining

12. Literature Stroje a zařízení I, J. Doleček, P. Gajdoš, V. Novák
Strojnictví I, J. Doleček, Z. Holoubek
Strojnictví II, J. Doleček, Z. Holoubek
Moderní strojírenství, Josef Dilinger a kolektiv

13. What are the advantages of friction wheels?
What materials are used for friction wheel construction?
Name at least 3 types of transmission by contact wheels.