Post on 25-Apr-2020
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Technical Orientation
Alex Ek & Michael Haber
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Overview
Three Major Product Lines
Couplings
U-Joints
Machined Springs
Over 26,000 different configurations
Defined by how they are being used
Let’s talk about couplings
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Technical Orientation Goals
Introduce flexible shaft couplings
Discuss the Helical coupling and how it works
Cover the possible variations of the coupling
Flexure
Material
Attachments
Virtues of the Flexure
Unvirtues of the Flexure
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Why Couplings?Definition: a connection or joint between two things.
http://en.wikipedia.org/wiki/Coupling_(disambiguation)
Shaft coupling: A connection between two shafts.
http://en.wikipedia.org/wiki/Coupling
Flexible shaft coupling: A connection between two unaligned shafts.
Must accommodate misalignment
Must transmit torque and position
Must survive its environment
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Why use a Flexible Coupling?Compensate for ____________ ?
Tolerances of machined parts
Dimensions effected by heat
Misalignments between shafts
All of the above
Sources of Misalignments ?
Misalignment Types
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What are Tolerances?Nothing is “perfect”
Tolerance is how much a dimension is allowed to deviate from “perfect”
Example:
Resonance Oscillator
Parts:
Motor
Motor Mount
Base
Bearing Block
Bearings
Shaft
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What are Tolerances?
Motor
Motor Mount
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What are Tolerances?
Base
Bearing Block
Bearing
Shaft
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What are Tolerances?Vertical tolerance stack up worksheet (inches):
Motor 0.002Motor Mount +- 0.005 Base 0Bearing Block +- 0.005Bearings 0.0005Shaft 0.0005
_________________________________________Maximum total 0.013
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Misalignments
Our rotating life tester
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Misalignments
Angular Misalignment
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Misalignments
Angular Misalignment – large angle
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Misalignments
Angular Misalignment – large angle
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Misalignments
Parallel Offset
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Misalignments
Parallel Offset - large
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Misalignments
Axial Motion
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Misalignments
Axial Motion - extension
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Misalignments
Axial Motion - compression
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What is Torque ?“A force applied across a distance from a center of rotation
creates twist or torque”
Torque ( lbin )= perpendicular force * distance
Units: lbin or Nm
“” = (63000*HP)/RPM (lbin)
What is the metric equivalent of Horsepower?
Watts or KW.
0.746 KW = 1 Hp.
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Foot-pounds and pound-feet—what’s the difference?
http://www.macsmotorcitygarage.com/2013/10/24/foot-pounds-and-pound-feet-whats-the-difference/
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Helical’s Torque Rating SystemMomentary Dynamic Torque
Listed in catalog
40% of Material yield strength
Non-Reversing Torque
Divide Momentary by 2
Reversing Torque
Divide Momentary by 4
Why torque and not horsepower?
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Torsional FlexibilityPredictable twisting from applied Torque
Similar words; “Torsional _________”
Stiffness
Rigidity
Wind-up
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Torsional Flexibility
Relaxed Wound Up
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Backlash
Unpredictable position due to clearances between input and output
Everything has Flexibility, Stiffness, Wind-up…
Not everything has backlash
Backlash
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Unique Helical Coupling Features
One-piece Construction
No Backlash
No Lubrication
Choice of Materials
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Flexure VersatilityColored Samples
Width of coils (Red)
OD & ID changes (Green)
Number of coils (Blue)
Number of starts (Gold)
Number of Flexures
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Width of Coils
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ID Changes (OD also)
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Number of Coils
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Multiple Start
Single Double
Triple
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Multiple Flexure
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Technical OrientationStandard Materials
Aluminum Alloy 7075-T6
Stainless Steel 17- 4 PH
Stainless Steel 303 (not our favorite)
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What is a Relief?
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Attachments
Standard Attachments
Integral Clamp Set Screw
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HP-85 print head positioner drive.
Circa 1980
What Needs a coupling?
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Food dispensing and Secret Medical Stuff
What Needs a coupling?
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What Needs a coupling?
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Aircraft engines and controls
What Needs a coupling?
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Technical Orientation
Flexure unvirtues
Yes, they can break!
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And next is . . .
Specifying and Promoting Couplings
With Derek & Tom