Chiropractor Help!Realign Your Misalignments For Longer Component Life

Chiropractor Help!Realign Your Misalignments For Longer Component Life

Matt McCloyEmerson Industrial Automation2012 Presentation

Why am I burning through v-belts?

Why are my gearbox’s leaking oil?

Why do I have backstop failures?

Why are my bearings failing?

Do You Ever Wonder….Do You Ever Wonder….

Did You Know…Did You Know…• …that all of these component

failures may be attributed to misalignment?

• …that one component failure may be due to the misalignment of another component?

• …like the bones in our body our connected, the components in your drive system are also connected…so a pain in one area, may be due to an issue in another area.

Today we are going to review common misalignments of interconnecting components…and how to realign these misalignments to get longer component life

Today we are going to review common misalignments of interconnecting components…and how to realign these misalignments to get longer component life

1. V-belt drives

2. Backstop

3. Gearbox

4. Bearings

5. Realignment Of All

Areas Covered Today As It Pertains To Misalignment:

Reasons Why Mechanical Components Fail:

Lubrication & Contamination

Shaft Lock

Misapplication

Installation

MISALIGNMENT

(19%)

Front View Side View

The components in your drive systems are all interconnected to each other…The components in your drive systems are all interconnected to each other…

Interconnectivity Between Mechanical Drive Components:

The v-belt drive connects the motor to the gearbox …there should always be 4 points of contact across both sheaves…

The v-belt drive connects the motor to the gearbox …there should always be 4 points of contact across both sheaves…

Misaligned V-Belt Drive Aligned V-Belt Drive

Result: V-belt failures, worn sheaves, loss of efficiency, misalignment on gearbox input shaft and oil leakage.

Worn Sheave New Sheave

> 1/32” Wear

To Correct Misalignment: a) Loosen motor mounting bolts & adjustb) Loosen sheave so it slides on shaft until

all four points touch straightedge.c) Consider motor mount assembly which

ensures proper alignment between motor and gearbox shaft.

To Check Alignment: Use a straight edge or a piece of string to ensure 4 points of contact are present.

A motor mount accessory will help with proper v-belt drive alignment…A motor mount accessory will help with proper v-belt drive alignment…

• Allows for quick and easy v-belt alignment and tensioning

Other benefits of a motor mount assembly include:

• Available in top or side-mount

• Eliminates the need for separate motor supports

• Predrilled for v-belt guards

• Allows for pre-assembled drive completed by manufacturer to save time and money on drive install.

Consider what a misaligned v-belt drive might do to an integral backstop on the gearbox…Consider what a misaligned v-belt drive might do to an integral backstop on the gearbox…

• Note that the driven sheave is mounted to the input shaft of the gearbox.

• This input shaft runs straight through the gearbox – on the back end is where the integral backstop is mounted.

Side View of GearboxImpact of Misaligned Sheave on Backstop

Backstop

To Correct Misalignment: Recall that a straightedge of a piece of string must have 4 points of contact with the sheaves for proper alignment. Ensure proper installation of backstop – refer to manufacturers installation manual if required.

V-belt drives and improper mounting of torque arms can contribute to gearbox alignmentV-belt drives and improper mounting of torque arms can contribute to gearbox alignment

• Excessive gearbox ‘wobble’

• Oil leaking from gearbox

• Gearbox running ‘hot’ (>160°F)

• Metallic fragments found in gear oil

• Worn gear teeth / spalling on one side of the gear teeth only

Diagnosing Gearbox Misalignment

Proper torque arm mounting – at 90° and in tension - is critical for gearbox alignmentProper torque arm mounting – at 90° and in tension - is critical for gearbox alignment

Step 2:

Determine reaction rotation of reducer

housing

Step 1:

Determine rotation of driven shaft

Step 3: Locate torque arm so it is being “pulled” by reducer housing and at 90° for optimum holding power and alignment

The drive shaft that the gearbox mounts to needs to be properly aligned for adequate bearing life…

The drive shaft that the gearbox mounts to needs to be properly aligned for adequate bearing life…

Static Misalignment: Bearings

To Check Alignment: a) Verify that the alignment of the bearing system is within 2°-3° total

or 1°-1.5° each way (depends upon bearing design/type; refer to bearing manufacturer)

b) Rotate shaft to make sure it rotates without any bindingc) Align set screws on both bearings.

1.5°

1.5°

Ball & Spherical Roller Bearings

To put this into perspective on a 5 ft length pulley shaft, a typical bearing can accommodate about 1-1.5” of static misalignment…

To put this into perspective on a 5 ft length pulley shaft, a typical bearing can accommodate about 1-1.5” of static misalignment…

BEARING ABEARING BElevation Change

1.5 Inches

Consider RPB Roller Bearings For Higher Misalignment In Your Bearings

+/-1-2°

BEARING ABEARING B

Elevation Change

3.2 Inches

Another form of misalignment is dynamic…this forms an eccentric shaft rotation causing the bearing to see varying misalignment angles…

Another form of misalignment is dynamic…this forms an eccentric shaft rotation causing the bearing to see varying misalignment angles…

Dynamic Misalignment: Bearings

What Happens When Dynamic Misalignment Present:• Bearing runs hot - rolling elements do not run in center of race causing friction

and grease wear.• Potential loss of lock – stress on locking mechanism causing vibration &

wobble.• May causes other problems with gearbox and v-belt drives.

To Minimize Dynamic Misalignment: a) Confirm correct shaft size in place (undersized shafting is often the most

common reason for dynamic misalignment).b) Check shaft for any imperfections and tolerances (e.g., bent shafts)c) Review bearing selection – spherical roller bearings are often the best suited

for applications involving dynamic misalignment

What does all this REALLY mean to you?What does all this REALLY mean to you?

• …a torque rm in compression and misaligned causes gearbox seal and bearing failure on input…conveyor running at 600TPH halts production for 1 day while parts are sourced and installed.

7,200 Tons LostProduction!

38,400 Tons Lost Production

• …2 15/16” bearings fail on snub pulley due to undersize shafting (dynamic misalignment)…conveyor producing 750 TPH is stopped for 2 days to change shaft and bearings.

• …a misaligned v-belt drive causes backstop failure… conveyor running at 800TPH back drives when belt fully loaded…halts production for 4 days to source and re-install parts and clean-up lost material.

18,000 Tons Lost Production!

Actual Examples: Misalignment Impact On Production

Conclusion: “An ounce of prevention is worth a pound of cure”Conclusion: “An ounce of prevention is worth a pound of cure”

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