Package ObsoleteModelica3.​Mechanics.​Rotational
Library to model 1-dimensional, rotational mechanical systems

Package Contents

NameDescription
GearObsolete model. Use Modelica.Mechanics.Rotational.Components.Gearbox instead
GearEfficiencyObsolete model. Use Modelica.Mechanics.Rotational.Components.LossyGear instead
InterfacesConnectors and partial models for 1D rotational mechanical components
TypesConstants and types with choices, especially to build menus

Model ObsoleteModelica3.​Mechanics.​Rotational.​GearEfficiency
Obsolete model. Use Modelica.Mechanics.Rotational.Components.LossyGear instead

Information

THIS COMPONENT IS OBSOLETE and should no longer be used. It is only kept for backward compatibility purposes. Use model Modelica.Mechanics.Rotational.LossyGear instead which implements gear efficiency in a much more reliable way.

This component consists of two rigidly connected flanges flange_a and flange_b without inertia where an efficiency coefficient eta reduces the driven torque as function of the driving torque depending on the direction of the energy flow, i.e., energy is always lost. This can be seen as a simple model of the Coulomb friction acting between the teeth of a gearbox.

Note, that most gearbox manufacturers provide tables of the efficiency of a gearbox as function of the angular velocity (efficiency becomes zero, if the angular velocity is zero). However, such a table is practically useless for simulation purposes, because in gearboxes always two types of friction is present: (1) Friction in the bearings and (2) friction between the teeth of the gear. (1) leads to a velocity dependent, additive loss-torque, whereas (2) leads to a torque-dependent reduction of the driving torque. The gearbox manufacturers measure both effects together and determine the gear efficiency from it, although for simulation purposes the two effects need to be separated. Assume for example that only constant bearing friction, i.e., bearingTorque=const., is present, i.e.,

   (1)  loadTorque = motorTorque - sign(w)*bearingTorque

Gearbox manufacturers use the loss-formula

   (2)  loadTorque = eta*motorTorque

Comparing (1) and (2) gives a formula for the efficiency eta:

   eta = (1 - sign(w)*bearingTorque/motorTorque)

When the motorTorque becomes smaller as the bearingTorque, (2) is useless, because the efficiency is zero. To summarize, be careful to determine the gear efficiency of this element from tables of the gear manufacturers.

Extends from ObsoleteModelica3.​Mechanics.​Rotational.​Interfaces.​TwoFlangesAndBearing (Obsolete model. Use one of Modelica.Mechanics.Rotational.Interfaces.PartialXXX instead) and ObsoleteModelica3.​Icons.​ObsoleteModel (Icon for an obsolete model (use only for this case)).

Parameters

TypeNameDefaultDescription
Realeta1Efficiency

Connectors

TypeNameDescription
Flange_aflange_aFlange of left shaft
Flange_bflange_bFlange of right shaft
Flange_abearingFlange of bearing

Model ObsoleteModelica3.​Mechanics.​Rotational.​Gear
Obsolete model. Use Modelica.Mechanics.Rotational.Components.Gearbox instead

Information

This component models the essential effects of a gearbox, in particular gear efficiency due to friction between the teeth, bearing friction, gear elasticity and damping, backlash. The inertia of the gear wheels is not modeled. If necessary, inertia has to be taken into account by connecting components of model Inertia to the left and/or the right flange.

Extends from ObsoleteModelica3.​Mechanics.​Rotational.​Interfaces.​TwoFlangesAndBearingH (Obsolete model. Use one of Modelica.Mechanics.Rotational.Interfaces.PartialXXX instead).

Parameters

TypeNameDefaultDescription
Realratio1transmission ratio (flange_a.phi/flange_b.phi)
Realeta1Gear efficiency
Realfriction_pos[:,2][0,1][w,tau] positive sliding friction characteristic (w>=0)
Realpeak1peak*friction_pos[1,2] = maximum friction torque at zero velocity
Realc100000Gear elasticity (spring constant)
Reald0(relative) gear damping
Angleb0Total backlash

Connectors

TypeNameDescription
Flange_aflange_aFlange of left shaft
Flange_bflange_bFlange of right shaft
Flange_abearingFlange of bearing

Generated 2018-12-12 12:17:46 EST by MapleSim.