DISC SPRINGS – STACKING - SPIROL · PDF fileDISC SPRINGS – STACKING STACK GUIDANCE...
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DISC SPRINGS – STACKING Consideration needs to be given to the friction between the parallel disc surfaces. A reasonable allowance is 2 - 3% of the force for each sliding surface – a greater force for loading and a lesser force for unloading. Discs in parallel should be well lubricated and it is suggested that the number of discs in a parallel set be limited to a maximum of 4 to reduce the deviation from calculated to measured characteristics. Discs in parallel have increased self-dampening (hysteresis) characteristics. Deflection: Same as single disc Force: Single disc multiplied by the number of discs IN PARALLEL IN SERIES Deflection: Single disc multiplied by the number of discs Force: Same as single disc IN COMBINATION Deflection: Single disc multiplied by the number of discs in series Force: Single disc multiplied by the number of parallel discs in a set METHODS OF STACKING regressive straight line progressive LOAD F DEFLECTION s STACKING Stacking individual Disc Springs provides the designer with: • A wide range of possible force/deflection combinations; • The ability to design application specific load curves – both progressive and regressive; and • The opportunity to design a range of dampening characteristics into the design. It is normally desirable to have both ends rest on the larger outer edge of the disc. With an uneven number of pairs in a stack, this is not possible. In this case, the end resting on the outer edge should be arranged to be on the end on which the force is applied – the moving end of the stack. STACK CONSTRUCTION RIGHT WRONG EVEN NUMBER OF DISCS RIGHT WRONG ODD NUMBER OF DISCS
Transcript of DISC SPRINGS – STACKING - SPIROL · PDF fileDISC SPRINGS – STACKING STACK GUIDANCE...
DISC SPRINGS – STACKING
Consideration needs to be given to the friction between the parallel disc surfaces. A reasonable allowance is 2 - 3% of the force for each sliding surface – a greater force for loading and a lesser force for unloading. Discs in parallel should be well lubricated and it is suggested that the number of discs in a parallel set be limited to a maximum of 4 to reduce the deviation from calculated to measured characteristics. Discs in parallel have increased self-dampening (hysteresis) characteristics.
Deflection: Same as single disc
Force: Single disc multiplied by the number of discs
IN PARALLEL IN SERIES
Deflection: Single disc multiplied by the number of discs
Force: Same as single disc
IN COMBINATION
Deflection: Single disc multiplied by the number of discs in series
Force: Single disc multiplied by the number of parallel discs in a set
METHODS OF STACKING
regr
essiv
e
straig
ht lin
e
prog
ress
ive
LOA
D F
DEFLECTION s
STACKING Stacking individual Disc Springs provides the designer with:
• A wide range of possible force/deflection combinations;
• The ability to design application specific load curves – both progressive and regressive; and
• The opportunity to design a range of dampening characteristics into the design.
It is normally desirable to have both ends rest on the larger outer edge of the disc. With an uneven number of pairs in a stack, this is not possible. In this case, the end resting on the outer edge should be arranged to be on the end on which the force is applied – the moving end of the stack.
STACK CONSTRUCTION
RIGHT WRONG
EVEN NUMBER OF DISCS
RIGHT WRONG
ODD NUMBER OF DISCS
DISC SPRINGS – STACKING
STACK GUIDANCE Stacks need to be guided to keep the discs in position. The preferred method is internal, such as a rod through the inside diameter. In case of external guidance, a sleeve is suggested. In either case, the guiding component should be case-hardened to a depth of not less than 0.6mm and a hardness of 58 HRC. A surface finish of ≤ 4 microns is also recommended.
De or Di
(mm)
Up to 16Over 16 to 20Over 20 to 26Over 26 to 31.5Over 31.5 to 50Over 50 to 80Over 80 to 140Over 140 to 250
CLEARANCE(mm)
0.20.30.40.50.60.81.01.6
Since the diameter of the discs change when compressed, the following clearance values are recommended:
PROGRESSIVE LOAD CURVES
Progressive loading can be obtained by assembling stacks in which discs will deflect consecutively when loaded. Generally, this is done by 1) stacking single, double and triple parallel sets in series, or 2) stacking discs of various thickness in series. It is, however, necessary to provide a means to limit the compression of the weaker disc to avoid overstressing while the stronger discs are still in process of compression.
DISC STACKS WITH PROGRESSIVE CHARACTERISTIC LOAD CURVES AND STROKE LIMITERS TO AVOID OVERLOAD
SLEEVEANDSTOP
WASHERSAND
RINGS
The stability of a disc with a thickness of 1mm or less can present a problem at the bearing surfaces. In such cases, the use of intermediate flat discs is recommended with outside diameter contact.
RIGHT WRONG
SPIROL Application Engineers will review your application needs and work with you to recommend the optimum solution. One way to start the process is to visit our Optimal Application Engineering portal at SPIROL.com.
© 2016 SPIROL International Corporation 11/14 Rev. 1
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