axle design
DESCRIPTION
Merritt is an Engineering Design Company, We offer complete product Design Solutions. Our domain expertise is in Design and Development of Chassis, Structures, Axles, Brakes, Steering System, Hydraulics and Electrical System for Mining, Construction and Farm Equipments and Industrial Products.TRANSCRIPT
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DESIGN OF AXLE FOR RIGID DUMP TRUCKS
AN OVERVIEWAbove 40 Ton Class
Content
• Snap Shot of Axel and Layout
• Overview of Axel Design
• Axel Specification
• Design Process
– Design Calculations
– Design of Components
• Example – Design of Axel Shaft
Snap Shot of Axel and Layout
RIGID DUMP TRUCK REAR AXLE
POWRTRAIN LAYOUT
Snap Shot of Axel and Layout
POWRTRAIN LAYOUT
Snap Shot of Axel and Layout
POWRTRAIN LAYOUT
Snap Shot of Axel and Layout
REAR VIEW
FRONT VIEW
Snap Shot of Axel and Layout
Manufacturing Drawings
Design Verification and Validation
Geometric Modeling of Axel
Axel Specification
Axel Type Load CapacityTorque
CapacityReduction
RatiosDifferential
SpecsBrake specs
Rim & Tire Specs
Wheel Tread
Axel Component Design
Differential Bevel Gears Planetary Gears Bearings Brakes Center Housing Axel Shafts
Torque Calculation
Prime-mover torque Slip torque from GVW
Vehicle Parameters
Engine Power Engine Torque Transmission Gear Ratio Tire Size
Overview of Axel Design
• Full-Floating Planetary AxelAxel Type
• Max Load • Max Torque
Axel Capacity
• Bevel Ratio • Final Drive Ratio• Total Ratio
Reduction Ratios
• Spiral Bevel Gear and Straight Bevel Gear Differential
Specification
• Oil Cooled Wet-multiple disk typeBrake Specification
• Rim Size• Tire Size• Wheel Tread
Tire Specification
Axel Specification
Following Vehicle Parameters considered
– Engine output power
– Engine output torque
– Transmission Gear Ratio• First Gear - For gradability
determination
• Top Gear – For top speed determination
– Selection of tire size
Design Process
• Torque Calculation
Input torque to axel is determined by calculating Prime-mover torque and Slip torque due to GVW, smaller of the both is considered as input torque to axel
Prime-mover torque
Slip Torque due to GVW
Design Process
• Design of Differential
– Type :
• Plug-in differential, conventional type
• Spiral and Straight Bevel Gears
Design Process
DIFFERENTIAL ASSEMBLY
Design Process
• Design of Bevel Gears
– Design methodology published by American Gear Manufacturing Association (AGMA)
– Gear teeth primarily designed for two factors• Resistance to pitting caused by contact stresses
• Bending strength capacity based on cantilever beam theory
– Material processing:• Heat treatment
– Convert weaker grain structures to stronger ones
• Tempering
– Relieve brittleness and internal strains prior to machining
• Carburization
– Adds high hardness and strength at surface and toughens core to withstand impact stress
Design Process
• Design of Bevel Gears
• Torque application to a bevel gear induces tangential, radial, and separating loads assumed to act as point loads applied at the mid-point of the gear tooth
• Reaction loads are a result of the tapered roller bearings that support the gear shaft and counteract the gear loads
• Loads are primarily a function of torque, pitch diameter, pitch angle, pressure angle, and face width
• Loads and bending moments are calculated based on a vectoral combination of two planes
Design Process
• Deign of Planetary Gears– Calculation of final drive ratio, No. of teeth, pressure angle, contact
ratio, tip diameter, tip width, root diameter, radial clearance, inspection parameters
– Calculation of gear bending and contact strengths
Design Process
• Bearing Life Calculation
– L10 Bearing life
– Speed and Load on Axel
– Duty cycle of usage
Design Process
• Design of Brake System
– Type : Wet-Multiple Disk Brakes
– Features :
• Effective cooling due to higher heat transfer rate
• Self adjustable disks
• Sealed – Free from dust & contamination
• Oil Cooled
• Retarder
Design Process
• Design of Brake System– Calculation of brake capacity
• Actual capacity
• As per SAE Standard
• As per ISO 3450
Basis of calculation
» Load on Axel – GVW
» Wheel Base
» Center of Gravity
» Gradability
» Loaded Radius
Design Process
• Design of Brake System
– Sizing of Brake
• Determining disk diameter
• Co-efficient of friction between disks
• Actuation pressure
• Disk area
• No. of disks
• FOS
Design Process
• Design of Central Housing
– Features :• 3 piece construction
• Steel casting
• Ease of manufacturing
Design Process
• Design of Axel Shaft
– Full floating axel shaft, no load on axel shaft
– Only torsional load
– Stress is calculated for
• Shear stress at body
• Compressive & shear Stress at spline
– Stress at bolted joints is calculated considering,
• Tensile stress developed due to clamping force
• External applied load
Design Process
Merritt Innovative Solutions India Private Limited
# 131/2, 1st Floor, West Of Chord Rd, 11th
Cross, 2nd Stage, Mahalakshmipuram,
Bangalore-86.
+91 80 23196515 / 516