Set collars and shaft collars- versatile in use
Set collars and shaft
collars (also called clamping rings) are simple components in drive technology,
but these components are widely used in the entire spectrum of mechanical and
plant engineering. Due to their innumerable possible applications, set collars
and shaft collars can be found in practically every system. They are used to
fix components or stop surfaces.
Set collars - The simple and inexpensive way of fastening
Despite their simple shape,
the adjusting ring is an indispensable element in securing mechanical stops in
drive technology. The holding force of the adjusting ring is ensured at certain
points via the threaded pin that fixes it on the shaft. Unfortunately, this
type of fixation causes damage to the shaft, which is sometimes unfavorable
from a functional point of view.
The set collar is mostly
manufactured according to DIN705. There are countless designs to choose from,
both in terms of size and material. There are small set collars for precision
mechanical applications as well as large set collars for demanding tasks and
greater loads.
Shaft collars - a safe further development on the shaft
Shaft collars are available
in two versions, one-piece and two-piece design. Allen screws provide the
necessary compressive force for positioning the shaft clamping ring and the
enclosure on the shaft. The most important aspect when installing a clamping
ring is that the shaft is not damaged. This is a clear advantage over a
conventional adjusting ring. Another important advantage is the even
distribution of the holding forces. Clamping rings can be dismantled quickly
and repositioned as often as required.
If you want quick and
uncomplicated installation and removal, you can use shaft collar, two pieces.
They can be quickly disassembled in place without removing other components on
the shaft.
Holding forces of the shaft collars - the decisive factor
Various features influence
the holding force of a clamping ring. Including factors such as concentricity,
bore sizes or surface properties. The holding force depends on the torque with
which the clamping screws are tightened and on the coefficient of friction
between the shaft and the clamping ring bore. The forces generated by the
screws between the shaft and the bore, multiplied by the existing coefficient
of friction, result in the maximum axial forces to be transmitted before
dynamics arise. The quality of the screws and the permissible tightening torque
also influence the holding force. The use of completely split clamping rings or
clamping rings in shaft grooves is one way of increasing the permissible axial
forces many times over, since in these cases there is a form fit instead of a
force fit.
As already mentioned, the
surface properties of the clamping ring also have an influence on the holding
force. Surface roughness and oil or fat deposits play a major role here. The
black oxide finish is often used, as this coating improves the torque
properties of the screws. The burnished finish of the clamping ring also
reduces the “slip-stick effect”.
Where are shaft collars used?
Shaft collars are used to
mount the following components on shafts, among others:
- Pulleys
- Ball bearing units
- Sprockets
- Drive wheels
As independent machine elements, clamping or tension rings are used, among other things, as:
- Guides
- Bridging of diameter
jumps
- Switching flags
- Centering
Special forms of shaft or
tension collars result in further possibilities of use. There are versions with
axial or radial bores in the area between the inside and outside diameter as
well as variants with machined surfaces or screwed-in grooves. Centering
collars are also conceivable on shaft collars.