Spring Is A Kind Of Elastic Component Widely Used In The Mechanical And Electronic Industries. When Loaded, The Spring Can Generate Large Elastic Deformation And Convert Mechanical Or Kinetic Energy Into Deformation Energy. After Unloading, The Deformation Of The Spring Disappears And Returns To As It Is, It Transforms Deformation Energy Into Mechanical Or Kinetic Energy. The Ratio Of The Load And The Deformation Of The Spring Is Called The Spring Stiffness. The Greater The Stiffness, The Stiffer The Spring.
First, The Role Of Spring
Buffering And Damping. Such As Damping Springs For Cars And Trains, Buffer Springs For Various Buffers, Etc.
Control The Movement Of The Body. Such As The Valve Spring In The Internal Combustion Engine, The Control Spring In The Clutch, Etc.
Store And Output Energy. Such As Clock Springs, Rifle Springs, Etc.;
Measure The Size Of The Force. Such As Spring Scales, Springs In Dynamometers, Etc.;
Second, The Classification Of The Spring
According To The Force Springs Are Divided Into: Tension Springs, Compression Springs, Torsion Springs And Bending Springs.
Tension Springs (Referred To As Tension Springs) Are Helical Springs That Withstand Axial Tension. Tension Springs Are Generally Manufactured From Circular Cross-Section Materials. When Not Under Load, The Tension Spring Is Normally Tight And Tight Without Any Gap.
Compression Spring (Referred To As The Compression Spring) Is A Coil Spring That Withstands Pressure. The Material Used In The Material Has A Circular Cross-Section, And It Is Also Made Of Rectangular And Multi-Strand Steel Coils. The Springs Are Generally Of Equal Pitch, And The Coils Of Compression Springs Are There Is A Certain Gap Between The Rings. When Subjected To An External Load, The Spring Shrinks And Deforms And Stores Deformation Energy.
Torsion Springs Are Helical Springs. The Torsion Spring Can Store And Release Angular Energy Or By Rotating The Arm Around The Axis Of The Spring To Statically Fix A Device. The Ends Of The Torsion Springs Are Fixed To Other Components That Pull Them Back To The Original Position When Other Components Rotate About The Center Of The Spring, Creating A Torque Or Rotational Force.
There Are Also Two Unusual Air Springs And Carbon Nanotube Springs;
The Air Spring Is A Kind Of Non-Metallic Spring That Incorporates Pressure Air In A Flexible, Airtight Container And Uses The Compressibility Of Air To Achieve Elasticity. It Can Greatly Improve The Ride Comfort Of A High-End Vehicle And Greatly Improve The Vehicle's Performance. The Comfort Of Operation, So The Air Spring Has Been Widely Used In Cars, Railway Locomotives.
Carbon Nanotube Springs: Carbon Nanotube Films Need To Be Produced First, And Then Carbon Nanotube Films Are Spun Into Carbon Nanotube Springs Using Spinning Technology. The Diameter Can Reach Hundreds Of Micrometers And The Length Can Reach Several Centimeters. It Is Expected To Be Applied In The Fields Of Retractable Conductors, Flexible Electrodes, Micro Strain Sensors, Super Capacitors, Integrated Circuits, Solar Cells, Field Emission Sources, Energy Dissipating Fibers, Etc. Applied To Medical Devices, Such As Tension Sensor Bandages.
Third, The Spring Material And Allowable Stress
Springs Are Often Subjected To Alternating And Impact Loads During Operation And Require Greater Deformation, So Spring Materials Should Have High Tensile Strength, Elastic Limit, And Fatigue Strength. In The Process Must Have A Certain Degree Of Hardenability, Not Easy To Decarburization, The Surface Quality Is Good.
Fourth, The Manufacture Of Springs
The Spiral Spring Manufacturing Process Includes: Rolling, Hook Making Or End Face Finishing, Heat Treatment And Process Performance Tests.
In Mass Production, It Is Rolled On A Universal Automatic Coil Spring Machine; In Single-Piece And Small-Batch Production, It Is Made On An Ordinary Lathe Or Hand-Made. When The Diameter Of The Spring Wire Is Less Than Or Equal To 8mm, The Cold Coil Method Is Commonly Used, And The Coil Is Heat-Treated Before Coiling And The Coil Is Cooled At Low Temperature. When The Diameter Is More Than 8mm, The Method Of Hot Coil (Hot Coil Temperature 800°C～1000°C) Is Adopted. After The Hot Coil Is Quenched And Tempered At Medium Temperature, The Surface Quality Inspection Shall Be Performed After The Spring Is Formed. The Surface Shall Be Smooth, Free Of Flaws, And Free From Decarburization. Defects; Springs Subject To Variable Loads Must Also Be Surface Treated By Shot Peening To Improve The Fatigue Life Of The Spring.
Fifth, The End Structure Of The Spring
Compression Spring In Addition To Participate In The Effective Number Of Deformation N, In Order To Make The Compression Spring Work Uniform, Ensure That The Centerline Of The Spring Is Perpendicular To The End Face, Each End Of The Spring Has 3/4 ~ 7/4 Laps And Tightly Support, Work When It Does Not Participate In Deformation, It Is Called A Dead Circle Or A Support Ring.
Extension Spring Ends Have Hooks For Mounting And Loading. There Are Four Types Of Commonly Used End Structures; Semi-Circular Shackles And Round Shackles Are Easy To Manufacture And Widely Used, But They Are Only Suitable For Springs With Spring Diameter D≤10mm Because Of The Large Bending Stress At The Transition Of The Hook. Adjustable And Rotatable Hooks Are Better Under Stress And Can Be Moved To Any Position For Easy Installation.
Sixth, The Spring Stress Calculation
▲ Force Analysis Of Compression Spring
Figure (A) Shows A Cylindrical Helical Compression Spring That Receives The Axial Working Load F. From The Cross-Sectional Analysis, It Is Known That The Spring Wire Has A Shear Force F And A Torque T = FD/2. The Shear Stress Caused By The Torque Is:
Considering The Influence Of The Shear Stress Caused By The Shear Force F And The Helical Curvature Of The Spring Wire, The Maximum Shear Stress T Occurs At The Inner Side Of The Spring (B). The Values And Strength Conditions Should Be:
In The Formula C—Winding Ratio, C=D/D, Can Be Selected According To Table 1.
K—The Spring Curvature Coefficient, K, Can Also Be Found Directly From Table 2. It Is Known From The Table That The Larger C Is, The Smaller The Influence Of K On T Is.
F—The Working Load Of The Spring N; D—The Diameter Of The Spring In The Spring; D—The Diameter Of The Material In Mm.
In Formula 1, The Formula For Calculating The Spring Wire Diameter According To The Strength Condition Can Be Obtained By Replacing F With The Spring's Maximum Working Load F2:
Tensile Spring Strength Calculation Method Is The Same As Compression Spring
Seven, The Spring Is Not In Place And The Cause Of Failure
In Practice, We Often Encounter Springs That Cannot Push A Moving Object To A Set Position, Which Means That The Calculated Free Length Of The Spring Becomes Shorter. The Main Reason Is That There Is No Initial Compression, That Is, A Manufactured Spring Is Compressed To A Higher Or Tighter Height (If Necessary) By A Greater Force, And Cannot Be Restored After He Is Released. Free-Length Operation. The Amount Of Shortening Is Called "Initial Compression." After Repeating 3-6 Compressions In General, The Length Is No Longer Shortened, Ie The Spring “Positions”. After The Initial Compression, The Spring Is Permanently Deformed.
Eight, Spring Preventive Measures
In Practice, The Compression Spring Should Maintain Its Working Length Even If It Is Subjected To Forces Beyond The Elastic Limit Of The Material. Therefore, The Length Of The Finished Spring Should Be Equal To The Calculated Length Of The Spring Plus The Initial Compression Amount, Which Can Avoid The Spring Not Being In Place, So As To Avoid Dangerous Stress When The Spring Coil Is Tight, Resulting In Abnormality Of The Spring Indicating Line And Not Being In Place. In The Heat Treatment Process, The Finished Product Spring Must Be Quenched And Tempered. In Particular, The Workpiece Must Be Placed Horizontally In The Furnace To Prevent The Spring From Shortening Due To Its Own Weight.
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