Torque Limiters SK

Please select a Product:

MODEL SERIES SK

SK1 / SKP

SK2

Selection of Torque Limiters

According to disengagement torque

As a rule Torque Limiters are rated according to the required disengagement torque, which must be greater than the torque that is necessary for regular machine operation.

The disengagement torque of the Torque Limiters is determined as a rule in accordance with the drive specifications.

The following calcucation has proven itself as a good rule of thumb:

T_KN = rated torque of coupling (Nm)
T_AS = peak torque of motor (Nm)

T_KN = rated torque of coupling (Nm)
P_AN = drive power (kw)
n = Velocidades of drive (min^-1)

According to acceleration torque (start-up at no load)

S_A = shock or load factor
S_A = 1 (uniform load)
S_A = 2 (non-uniform load)
S_A = 3 (high dynamic load)

Values for SA = 2-3 are usual for servo drives on machine-tools.

T_KN = rated torque of coupling (Nm)
α = angular acceleration

t = acceleration time (sec.)
ω = angular Velocidades in (1/s)
n = Speed of drive (min^-1)
J_L = moment of inertia on load side (kgm²)
J_A = moment of inertia on driving side (kgm²)
T_AS = peak torque of motor (Nm)

According to acceleration and load torque (start with load)

S_A = shock or load factor
S_A = 1 (uniform load)
S_A = 2 (non-uniform load)
S_A = 3 (high dynamic load)

Values for SA = 2-3 are usual for servo drives on machine-tools.

T_KN = rated torque of coupling (Nm)
α = angular acceleration

t = acceleration time (sec.)
ω = angular Velocidades in (1/s)
n = Speed of drive (min^-1)
J_L = moment of inertia on load side (kgm²)
T_AN = load torque (Nm)
J_A = moment of inertia on driving side (kgm²)
T_AS = peak torque of motor (Nm)

According to feed force

Spindle drive

T_AN = load torque (Nm)
S = spindle pitch (mm)
F_V = feed force (N)
η = spindle efficiency

Timing belt drive

T_AN = load torque (Nm)
d₀ = pinion dia. (pulley)
F_V = feed force (N)

According to resonant frequency (SK2 / 3 / 5 with bellows attachment)

Usually high resonant frequencies of the couplings are required in order to make high acceleration values possible and to avoid any excessive vibration.

For the purpose of caclulation the drive is reduced to a 2 mass sytem.

C_T = torsional stiffness of the coupling (Nm/rad)
J_Masch. = moment of inertia of machine (kgm²)
(spindle + slide + workpiece + half of coupling)
J_Mot. = moment of inertia of motor (kgm²)
(motor’s rotor + half of coupling)
f_e = Resonant frequency of a two mass system (Hz)

According to torsional sitiffness (SK2 / 3 / 5 with bellows attachment)

Transmission errors due to a torsional stress on the metal bellows:

= angle of turn (degrees)
C_T = Rigidez torsional of coupling (Nm/rad)
T_AS = peak torque of motor (Nm)

According hasta the function system

Sujeción de carga version: On SK1 / SKP modelos the Sujeción de carga version has a double load safety margin. Ensure that modelos with bellows (SK2, 3 and 5) are of adequate size. The overload torque in this case should not exceed the nominal torque of rating the safety coupling.