U.S. TSUBAKI POWER-LOCK ®
AS Inch/Metric Series Selection Guide and Specifications
D: Hub bore inside dia. (in.) D N : Min. hub dia. (in.)
1. Selection of POWER-LOCK ® a) When only torque is applied:
Compare the max. transmitting torque (T max.) of the devices to be driven with the transmissible torque (Mt) of the POWER-LOCK listed on pages D-21, D-24, and D-25. Mt T max . . . OK Mt < T max . . . Select a larger POWER-LOCK or use two or more POWER-LOCK units. The transmissible torque (Mt) of multiple POWER-LOCK units is obtained by multiplying Mt by the number of units used. Peak torque expected should be regarded as T max. Torque 5252 • HP • s.f. = T max. n (ft./lbs.) - - - (1) n: RPM s.f.: Safety Factor
c) Hollow Shaft Application: Inside diameter of the hollow shaft: d B Compute inside diameter of hollow shaft.
Y.P. – 2•P•K 3 d B d ––––––––––
- - - (4)
Y.P.
d: P:
Outside diameter of shaft (in.)
Contact pressure on shaft side (Refer to pages D-21, D-24 and D-25) (psi)
K3: 0.6 ... Using single POWER-LOCK K3: 0.8 ... Using multiple POWER-LOCK
b) When torque and thrust are applied: Compare Mt with composite torque M R . M R = T 2 max. + (P max. • – ) 2 Mt.
3. Hub width The AS Series POWER-LOCK is not self-aligning. Thus centering (B – b) must be performed. Suggested “guide length” (B – b) is to be equal to or greater than one half of the shaft diameter. B – b d/2 (d: shaft diameter) Hub width (B) can be calculated as follows: B b + d/2 - - - (5) Note: POWER-LOCK cannot be centered under the condition of B = .
d 2
- - - (2)
T max: Maximum torque (ft./lbs.) P max: Maximum thrust load (lbs.) d: Shaft O.D. (ft.)
2. Hub diameter calculation
4. Machining tolerance and surface roughness
a) Standard hub diameter (flange coupling, V sheave, etc.): Min. hub outside diameters (D N ) are shown on pages D-22, D-23, D-26 and D-27 based on the yield point of hub material and the length of the hub. Hub diameter must be equal to or larger than (D N ). Special hub diameter can be calculated by the following: b) Hubs of special material: Calculate hub diameter using the following formula (not applicable to non-ferrous metals).
Machining tolerance for counter bore diameter of hub “D” and shaft diameter “d” are listed on pages D-21, D-24 and D-25. Required surface roughness of 125 RMS. Determine the tolerance of the guide according to the centering accuracy required.
Y.P. (hub) 1.4P ’ Y.P. (shaft) 1.4P
Y.P. + K 3 •P ’ Min. hub. dia. D N D –––––––––
- - - (3)
Y.P. – K 3 •P ’
K 3 : 0.6 ....Using single unit b L 1 , B 2 K 3 : 0.8 ....Using multiple units b n • L 1 B n • L 1 + L 1 K 3 : 1.0 ....Using single unit B < 2 • Using multiple units + L 1 B < L 1 (n + 1)
(n: number of POWER-LOCK)
P ’ : Contact pressure on hub (psi) Y.P.: Yield point of hub material (psi)
D-29
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