FAQs
Special Retaining Ring Designs
What type of retaining ring might I use if Ring take-up capability [d/2 (tan 15 deg.)] ≥ Δ A + Δ B + Δ U
accumulated tolerances or wear have caused Variation in retained part width (Δ B)
objectionable end play in my assembly? Variation in groove location (Δ A)
There are two types of retaining rings you might consider using Variation in ring beveled edge (Δ U)
to avoid this problem. Bowed rings are specifically designed to
Groove location limits (Amin and Amax) can be calculated as follows:
have a resiliency to this issue by functioning as both a spring and
a fastener. They are also used to dampen vibration and oscillation Amin = Bmax + Umax + d/2 (tan 15 deg.)
and are available as axial and radial retaining rings. Amax = Bmin + Umin + d (tan 15 deg.)
The second method involves a beveled retaining ring, which What if I have higher load requirements than
provides a rigid end play take up, functioning as a wedge between most other applications?
the groove and the retained part. It also reduces assembly time by There are retaining rings for almost every application. For very-
avoiding measuring of accumulated tolerances and using select high-load requirements, companies are able to provide reinforced
fit parts. Beveled rings are only available in an axial ring style for retaining rings offering greater thicknesses and different shapes,
applications greater than 1 in. depending on the application.
How would I calculate for bowed Are products available for custom groove
and beveled retaining rings? dimensions?
These formulas are easy to understand and implement. For bowed That depends on the company you’re working with. For example, in
retaining rings, it is necessary to locate grooves carefully in order addition to offering designs to fit standard groove dimensions, Rotor
to maximize end-play take-up resilience. There are two basic Clip also offers unlimited spiral retaining ring designs made from flat
configurations you’ll run into, as shown in the drawings for internal wire to fit custom groove dimensions. The number of turns on a flat wire
and external designs. The formulas for groove location are: ring can be increased to improve ring strength and fill wider grooves.
Amax = Bmin + Jmax,
Amin = Bmax + Jmin,
Jmax − Jmin = resilient
take-up tolerances of
groove location A and
width B of retained part.
For beveled retaining rings, there is a minimum and maximum insertion
measurement. Here is the methodology needed (see drawing):
This section view of an internal beveled retaining ring shows how it wedges
Sponsored by itself in the complimentary groove to take up tolerances while locking the
retained part rigidly in place.
I’ve noticed that retaining rings have an
rpm limit. What determines this?
When you have a rotating shaft that is using an external
retaining ring, you are susceptible to centrifugal forces.
This means that the ring you are using can fail when
these forces become strong enough to lift the ring out
of the groove.
How can I maintain higher rpm limits
and not lose the retaining ring?
Tapered rings with stronger radial spring force may be
considered to improve rpm limits. It is also possible to
increase your rpm limits by using spiral retaining rings
with a special interlocking feature in your application.
These are great examples. Is there
anything specific I’ll need to consider
when designing in a retaining ring?
One of the important things to consider when selecting
a retaining ring is clearance. This is important for
several reasons. Even if you choose the perfect
retaining ring for your application, if you don’t have
room to install it on the production line, you’ll have
a problem. The same holds true for removing and
reassembling a retaining ring during inspection, field
service, or repairs. Further, axial and radial clearances
must also be considered in relation to abutting or
adjacent components in the assembly.
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