Flexible Couplings COUPLING NOMENCLATURE - …

1 Flexible CouplingsPage V-C COUPLING NOMENCLATUREF lexible Couplings Page C-1C . C OUPL ING NOM ENC L A T URETermDefinitionAccessory SetAccessory Set is package of hardware used to assembly COUPLING components. T his mayinclude, fasteners, lube plugs, shims, plate, gaskets, PlateAn adapter plate, also known as a solo plate, is an auxiliary device required to rigidlyhold in alignment the floating sleeve at the drive end of a flex-hub COUPLING to allowsolo operation of the driver without the necessity of dismounting the COUPLING S haftW hen aligned, the two shafts are coaxial with a specified separationAligning S urfaceAligning S urface is used to establish the axis from which a part (or COUPLING )

2 Is locatedfor the purpose of SpeedAllowable speed relates to application conditions and experience, and includesconsideration of misalignment, loading, and system characteristics. Allowable speedshall not exceed rated maximum speed rating of the Misalignment DoubleEngagementFor a double-engagement COUPLING , COUPLING angular misalignment is the minor anglebetween the axial centerline of the structure joining the two flexing elements and either ofthe shaft centerlines. T hus, there are two misalignment angles associated with a double-engagement COUPLING .

3 T hese two angles are not necessarily equal, since they are theresult of common parallel offset combined with the angular misalignment of therespective shaft Misalignment-GeneralAngular misalignment is the minor angle between two shafts when the two shafts are notcoaxial, and their axes are not Misalignment-SingleEngagementFor a single-engagement COUPLING , COUPLING angular misalignment is the minor anglebetween the two shaft Gear CouplingDesignAn anti-sludge design minimizes sludge-gathering pockets in continuously F actor (see S erviceF actor)Service factor or Application Factor is applied to the normal operating torque.

4 Itaccounts for unusual conditions that may occur receptively such as compressor fouling,or may account for the real operating conditionsAssembly BalanceAssembly balance is a procedure where a complete assembled COUPLING is balanced as DisplacementAxial displacement is a change in the gap between the shaft ends of two coupledmachines, usually caused by thermal expansion. Axial Natural FrequencyAxial natural frequency (ANF): is a cyclic response frequency determined by the mass ofthe Flexible center element acting against the axial spring rate of the Flexible spring rate may vary with the deflection of the Flexible element.

5 Therefore, afrequency band corresponding to deflection amplitudes from zero to the maximumallowable amplitude must be Reaction Force(Transmitted Axial Force)Transmitted axial force is the axial force transmitted through the COUPLING imposed bythe operating conditions (axial deflection, misalignment, speed, temperature, etc.)Axial Reference PointAxial reference point: the axial position on the shaft of the driving or driven machine(normally the extreme end of the shaft) from which axial distances are measuredAxial StiffnessAngular stiffness is a measure of how much force or bending moment is required toangularity misalign a COUPLING to a specified angle while under torque LifeThe B10 Lif e of an univ ersal joint bearings def ined as the lif e expectancy f or a 90%probability of surv iv Couplings Page C-2 TermDefinitionB acklashB acklash is the circumferential clearance in the Flexible element(s)

6 That is necessary toprovide angular misalignment capability and Gear CouplingA batch-lube COUPLING is designed to be lubricated by a periodically changed charge ofgrease or (angular) stiffnessBending (angular) stiffness is the ratio of restoring moment to angular ouplings which slide while accommodating angular misalignment do not possessangular stiffness since material deflection does not occurBushingT he bushing is an adapter or adapter assembly used to mount the COUPLING componentsor COUPLING assembly on the mandrelCenter of GravityCenter of gravity for a half COUPLING is the location at which the weight of that halfcoupling can be considered to be concentrated.

7 T he half effective center of gravity isreferenced from the equipment shaft end; with a positive location being beyond the shaftend and a negative location being within the CouplingA chain COUPLING consists of two hubs with sprocket teeth which engage or mesh with astrand of BalanceC heck balance is a procedure wherein an assembled COUPLING is placed on a balancemachine and the potential unbalance is measured. T his can be done to a componentbalanced COUPLING , or to an assembly balanced Fit BoreA clearance fit bore designates a condition where the hub bore diameter is equal to orlarger than the shaft diameterComponent BalanceComponent balance is a procedure for improving COUPLING balance in which thecomponents or factory assemblies are balanced before assembly of the couplingContinuous T orque RatingCoupling continuous rated torque (T c).

8 Is the COUPLING manufacturers value of torquecapabilities of the COUPLING utilizing a combination of speed, angular misalignment, andaxial GearCouplingA continuous-lube COUPLING is designed to be lubricated by a continuous external supplyof oil directed at or into the gear Mass SimulatorCoupling mass simulator: an auxiliary device designed to correctly simulate both theeffective mass and the effective location of the center of mass of a half COUPLING withrespect to the shaft on which it is Rated Speed(Maximum speed) COUPLING rated speed the maximum speed at which the COUPLING is capable oftransmitting the COUPLING continuously rated torque where simultaneously subjected tothe rated angular misalignment and the COUPLING rated axial oupling ratingC oupling rating is a torque capacity at rated misalignment, axial displacement and speedCoupling flywheel effect (WR2)(Polar weight moment of inertia) COUPLING flywheel effect (WR2) (Polar weight moment of inertia) is a measure of thepotential of the COUPLING to resist change in speed.

9 WR2 is the product of the weight ofthe COUPLING times the square of the radius of gyration. T he radius of gyration is theradius at which the mass of the part ( COUPLING ) can be considered concentratedC rown DiameterT he crown diameter is the major diameter of the external gear teethDampingDamping is the absorption or dissipation of oscillatory energy. Damping may benecessary to limit the buildup of transient or steady state resonant oscillations in asystemDamping coefficientDamping coefficient is the ratio of damping energy during one cycle to elasticdeformation energyDamping ratio (factor of criticaldamping)Damping ratio is the ratio of actual damping coefficient (C) to the critical dampingcoefficient (CC).

10 The critical damping coefficient is a measure of the minimum dampingthat will allow a displaced system to return to its initial position without Couplings Page C-3 TermDefinitionDesign Factor of Safety ( )Design Factor of Safety ( )is the factor of safety at the catalog rated conditions oftorque, speed, misalignment and axial displacement. It is used by the manufacture toestablish the COUPLING rating,Diametral C rown C learance (tipclearance)T he Diametral crown clearance is the clearance between the outside diameter of thecoupling's external teeth (whether on a hub or on a marine spool piece) and the rootdiameter of the internal teeth in the sleeve when the COUPLING is in perfect COUPLING (metallicdiaphragm COUPLING )Metallic diaphragm COUPLING .