Friction Clutch Design

Made by: Ina Efremova, fac.no. 221206036

Svetoslav Ovcharov, fac.no. 221206020 Kiril Iliev, fac.no. 221206007

Design of a friction clutch

Specifications:• Clutch purpose: actuated 2-disk clutch• Type of actuation: mechanically• Driven machine nominal torque: Tnom=750 N.m

• Nominal input speed: n1=650 min-1

• Type of prime mover: electric motor• Type of driven machine: passenger elevator• Operating conditions: dry• Number of clutch engagements per hour: 30 h-

1

What is clutch?

A clutch is a mechanism for transmitting rotation, which can be engaged and disengaged. Clutches are useful in devices that have two rotating shafts. In these devices, one shaft is typically driven by a motor and the other shaft drives another device. The clutch connects the two shafts so that they can either be locked together and spin at the same speed (engaged), or be decoupled and spin at different speeds (disengaged).

Motor, Clutch and Pulley of an elevator in a panel block of flats

Design of the clutch• We have chosen steel and sintered bronze for

the friction surfaces. • Our clutch has two driving and two driven

disks, and 3 pairs of friction surfaces, which means that in our case z=3.

• The switching mechanism consists of three levers.

• We also have two key joints, one for each shaft.

Design of the shaft• We calculated that the minimum shaft

diameter “d” must be greater than 33,47 mm. Therefore we choose to take 35 mm.

Design of the disks• We calculated the allowable surface pressure [p],

which in our case is 1,4 MPa.• First we calculated Dave’, which is 0,061 m in order to

obtain the values of the working width “b” and the minimum friction disks diameters “D1” and “D2”(b=0,015m; D1=0,076m; D2=0,046m).

• From construction point of view we took: D1=0,095m and D2=0,071m.

• With the new values of D1 and D2, we finally calculated the average diameter Dave=0,083m and b=0,012m. For the normal pressing force of the disks’ surfaces F we obtained the value of 3012 N.

Key joint design• We choose standard key joint from Bulgarian

National Standards 10X6X40 по БДС 13599-76 with the following parameters: b=0,01m; h=0,006m; t1=0,0035m; t2=0,0028m; l=0,04m.

• Therefore we calculated that the minimum working length of the key joint is lpmin=0,0298m. We took lp to be 0,03m.

Switching lever• Taking into consideration the design of our

friction clutch, we determined the following values for the switching mechanism:

a=0,066m; m=0,024m; b=0,012m; r=0,0065m; c=0,02m;

• The calculated values for the normal force FN and for the switching force Fvkl are respectively 1539,6 N and 526,5N.

Assembly 3D

Thank you for your attention!