A disc coupling, by definition, transmits
torque
In physics and mechanics, torque is the rotational equivalent of linear force. It is also referred to as the moment of force (also abbreviated to moment). It represents the capability of a force to produce change in the rotational motion of th ...
from a driving to a driven
bolt or
shaft tangentially on a common
bolt circle
A bolt circle diameter or pitch circle diameter (PCD), sometimes simply called bolt circle or pitch circle, is a common term for when a number of screw holes for bolts are evenly distributed with their centers along an imaginary circle with a giv ...
. Torque is transmitted between the bolts through a series of thin,
stainless steel
Stainless steel is an alloy of iron that is resistant to rusting and corrosion. It contains at least 11% chromium and may contain elements such as carbon, other nonmetals and metals to obtain other desired properties. Stainless steel's corros ...
discs assembled in a pack. Misalignment is accomplished by deforming of the material between the bolts.
A disc coupling is a high performance motion control (
servo
Servo may refer to:
Mechanisms
* Servomechanism, or servo, a device used to provide control of a desired operation through the use of feedback
** AI servo, an autofocus mode
** Electrohydraulic servo valve, an electrically operated valve that ...
)
coupling
A coupling is a device used to connect two shafts together at their ends for the purpose of transmitting power. The primary purpose of couplings is to join two pieces of rotating equipment while permitting some degree of misalignment or end mov ...
designed to be the torque transmitting element (by connecting two
shafts
''Shafts'' was an English feminist magazine produced by Margaret Sibthorp from 1892 until 1899. Initially published weekly and priced at one penny, its themes included votes for women, women's education, and radical attitudes towards vivisection, ...
together) while accommodating for
shaft misalignment. It is designed to be flexible, while remaining
torsionally strong under high torque loads. Typically, disc couplings can handle speeds up to 10,000
r/min.
Types
There are two different styles of disc coupling:
* Single disc style couplings are composed of two hubs (the ends of the coupling, which are typically made from aluminum, but stainless steel is used as well) and a single, flat, stainless steel disc spring.
* Double disc style couplings are also composed of two hubs, but has an additional center spacer sandwiching two disc springs. The center spacer can be made out of the same material as the hubs, but is sometimes available in insulating acetal, which makes the coupling electrically isolating.
The difference between the two styles is that single disc couplings cannot accommodate parallel misalignment due to the complex bending that would be required of the lone disc. Double disc styles allow the two discs to bend in opposite directions to better manage parallel offset. The discs are fastened to the hubs (and center spacer on double disc styles) with tight fitting pins that do not allow any play or backlash between the disc and the hubs. The discs can be bent easily and as a result, disc couplings have some of the lowest bearing loads available in a motion control coupling.
Use
Torsionally stiff and still flexible, disc couplings are a great solution for high speed applications. The downside is that they are more delicate than the average coupling and can be damaged if misused. Special care should be taken to ensure that misalignment is within the ratings of the coupling.
See also
*
Compliant mechanism
In mechanical engineering, a compliant mechanism is a flexible mechanism that achieves force and motion transmission through elastic body deformation. It gains some or all of its motion from the relative flexibility of its members rather than fro ...
*
Oldham coupler
A coupling is a device used to connect two shafts together at their ends for the purpose of transmitting power. The primary purpose of couplings is to join two pieces of rotating equipment while permitting some degree of misalignment or end mov ...
*
Rag joint
A rag joint refers to certain flexible joints (flexure bearings) found on automobiles and other machines. They are typically found on steering column shafts that connect the steering wheel to the steering gear input shaft, usually at the steeri ...
*
Thompson coupling
Constant-velocity joints (also known as homokinetic or CV joints) are mechanical joints which allow a drive shaft to transmit power through a variable angle, at constant rotational speed, without an appreciable increase in friction or play. They ...
*
Universal joint
A universal joint (also called a universal coupling or U-joint) is a joint or coupling connecting rigid shafts whose axes are inclined to each other. It is commonly used in shafts that transmit rotary motion. It consists of a pair of hinges lo ...
References
{{Reflist
Rotating shaft couplings