Belleville Spring Washers
Stock sizes in high-carbon and stainless steels
Belleville spring
washers are especially suited for high loads in small spaces. By
combining them in varying sequence, each size gives numerous load-carrying
possibilities. These washers have had all set removed during manufacture.
Material
Spring Steel
Commercial - 1074 - Certified to ASTM-A684
Stainless steel
Thicknesses up to and including 0.072 in.
Commercial - Type 302
Government - AMS 5906 Type 302 Chemistry only
Thicknesses over 0.072 in.
Commercial - Type 17-7 PH certified to AMS 5528
No charge for certificate
of compliance when requested; certificate of chemical analysis
available, see price book. Tolerances
Contact our engineering department for tolerances.
Typical load-deflection curves for three characteristic proportions
of washers listed are as shown in Fig. 2. From them, loads at intermediate
heights may be estimated. The nominal amount of dish or cone (h)
is found by subtracting "t" from "H".
Example
Using part no. B1250-040, estimate the load at 75% of deflection:
h = H - t = 0.082 - 0.040 = 0.042
h ÷ t = 0.042 ÷ 0.040 = 1 approx.
From Fig. 2, using the curve "h = t", the load at 75% of
the deflection is 87% of the load at flat position. From the table, calculated
load at flat is 330 lb.; .87 x 330 = 287 lb. The typical curves in Fig.
2 are shown with dotted lines beyond 75% of deflection to indicate that
load characteristics in this area are not reliable because of partial
bottoming of the washers.
Stacked Belleville Spring Washers
Since the deflection in a single
belleville spring washer is relatively small, it is often necessary
to combine a number of washers. Stacking them in series increases the
deflection in proportion to the number of washers, the load remaining
the same as with a single washer.
In order to increase the load, the washers may be stacked in parallel
as shown in Fig. 1. Theoretically, this increases the load in proportion
to the number of washers. However, friction between the washers causes
an apparent "hysteresis" in the load-deflection curve as illustrated
in Fig. 3. This figure shows test curves made on laboratory equipment
without vibration using part no. B1000-035. The width of the "hysteresis" loop
is in the order of 6% for each washer added in parallel, but it may vary
with lubrication and surface finish and may change during the life of
the mechanism due to burnishing of adjacent surfaces. The test curve
in Fig. 3 for five in parallel also illustrates the extra deflection
which occurs due to imperfect nesting of the washers. The graph in Fig.
3 is labeled to show the loads and deflections of the single washers
in the stacks.
A stack of washers may be installed either on a rod or in a cylinder.
For dynamic applications the guides should be hardened to Rockwell C48
minimum. Also hardened flat end plates may be added to prevent indenting
adjacent parts.
Belleville Spring Washers For Flange Applications
Stock sizes in
stainless steels
SPEC flange bellevilles are designed to compensate for thermal
expansion and mechanical shock associated with bolted joints.
Typical applications include valves, pipe connections, pump connections
and compression joints. These washers have had all set removed
during manufacture.
Material
Stainless steel
Commercial - Type 17-7 PH
Maximum application temperature for 17-7 PH is 570 deg F (300
deg C).
Certificate of chemical analysis available at extra cost.
Stacked
belleville washers
Additional load or deflection can be obtained
by the stacking of bellevilles in series or parallel. See the standard
line of belleville spring washers for information on stacking of
belleville washers.
Load tolerances
Load tolerances are plus or minus 20.0% of the values
shown. High Load Belleville Spring Washers
Stock sizes in high-carbon steel
SPEC high load belleville washers provide loads which are substantially
greater than our standard washers of similar diameters. These
washers have had all set removed during manufacture since most applications
are static applications. Set generally is removed during installation
which results in a reduction of the free height.
Material
Carbon spring steel C1070-C1075 or chrome vanadium based on availability
at time of manufacture.
Certificate of chemical analysis available at extra cost.
Parts made from 17-7 PH are available as a special order.
Stacked belleville washers
Additional load or deflection can be obtained by the stacking
of bellevilles in series or parallel. See the standard line of
belleville spring washers for information on stacking of belleville
washers.
Loads
Maximum load is achieved at flat. Loads are calculated values.
Metric Disc Spring Washers
Stock sizes in high-carbon or chrome vanadium
All SPEC Disc washers
are manufactured to the European Din 2093 specification. These
designs are the same reliable designs that have been sold for years in
Europe by Associated Spring.
Additional Din sizes are available upon request.
Material
Material thickness less than 1.25 mm - Carbon Steel per C1074
- 1075.
Material thickness 1.25 mm and up.
Chrome Vanadium per SAE 6150.
Certificate of chemical analysis availableat extra cost.
Stacked disc springs
Additional load or deflection can be obtained
by stacking disc springs in series or parallel. See section on
standard belevilles.
Load tolerances
Diameter tolerances I.D. - O.D. + 0.013 mm - 0.077
mm
Material thickness
Less than 1.25 mm, + 25.0% - 7.5%
1.25 mm to 3.0 mm, + 15.0% - 7.5%
3.1 mm to 6.0 mm, + 10.0% - 5.0%
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