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Efficiency

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Introduction

➢ Efficiency is an important performance criteria for gearboxes.

➢ Gearbox elements produces some power loss:

➢ Load dependent losses are frictional losses between components and no-load speed losses are due to viscous drag forces on the components.

➢ Efficiency calculated using ISO/TR 14179-1.

➢ This is not an internationally accepted standard and many designers modify equations to match their in house experiments.

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Gravity Orientation

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Design mode

Set Gravity Magnitude and OrientationX: -0.248Y: -0.9688Z: 0

Accept the fix if specified orientation is not a unit vector

Specify Oil Level

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Copyright Shell

Set the oil level:-62.5mm

Visible as a plane in 3D view

Open Lubrication Database

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Select Lubrication Detail

Select Add Lubricant

Specify Oil Properties

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SAE Viscosity Grade 75W-90 85W-140

Kinematic Viscosity @40°C mm2/s 115 358

Kinematic Viscosity @100°C mm2/s 15.2 25.6

Viscosity Index 138 94

Density @15°C kg/m3 878 908

Flash Point °C 210 215

Pour Point °C -42 -15

➢ Add a couple of lubricants by modifying the viscosities and density

Enable Efficiency Analysis

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Load case and duty cycles mode

Enable efficiency calculationSelect a load

case and go to the settings tab

Load Case Efficiency Results

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Select a load case

Connection and component efficiency results

Overall efficiency results

Next task…

➢ Please now work through the document:

7.Cylindrical Gear Micro Geometry

➢ The next slide in this document contains some additional tasks you might want to attempt after completing all the other tutorials

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Some additional tasks

1. How does oil level effect the efficiency?

2. How does oil type (i.e. Density, Viscosity) effect efficiency?

3. How does torque and speed change efficiency?

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