Quick Connect Wheels

Introduction

LifeTrac wheel couplers suffered catastrophic failure when used with tracks.

.

The key on the motor shaft sheared. We put on thicker couplers, and LifeTrac currently works - but we will not take it through destructive testing prior to testing splined motors. NOTE: Discussion at 31.88 Cubic Inch Motors shows hints that pressure setting was too high, and could have been the reason for failure.

.

It is suspected that the 4-wheel drive, when coupled by wheel tracks, makes the motors fight each other.

Removing Tracks, Adding Quick Connect Wheels

To remedy the failing coupler, we will remove the tracks as the first step, and run the motors in series to simplify control valve requirements. That means that a 3000 PSI pump can deliver a max of 1500 PSI to each motor. This puts a low limit on the pressure, while delivering 6525 in lb for each motor - which makes this still higher torque than the 5000 cu in former 31.88 cu in motors used on LifeTrac I-III.

The rough concept of a quick connect wheel is this:

Implementation

To design the quick connect wheel, complete LifeTrac Frame geometry must be considered.

See pictures of wheeel:

• 
• 
• 
• 

and the real object:

. . .

Concept Quick Release Wheel

Design Rationale:

• Triple mechanism of holding using pin, a cam, and a bolt:

Download File:Wheelmount.dxf

See it:

Model:

[[Image:wheelmodel1.jpg]

Download pngs of above and STEP file - File:Wheelmodel.zip

Solution Pathways for Addressing Failing Motor Couplers

Solution Pathway 1

Concept:

• Use a motor with more torque
• Direct coupling to wheel eliminates bearings, shafts, and collars
• Retain tracks
• Use one motor per side to eliminate motors 'fighting each other'

Possible solution: 15,000 Inch Pound Motor

Solution Pathway 2

• Use 2 motors per side, and same drive train as in LifeTrac Wheel Assembly Video, but with splined shaft motors
• Do motors 'fight each other' in this case?
• The new splined motors are these from Surpluscenter:

Splined shaft wheel motors from Surpluscenter

31.88 cubic inch wheel motors from Surpluscenter

Pathway 3

• Reduce pressure on hydraulic motors?
• 1160 PSI only is max on 31.88 Cubic Inch Motors. Is this sufficient to drive the tractor?

Peer Review

This page should be peer reviewed by hydraulics specialists, such as at hydraulics forums.