IQS Newsroom Articles on Shaft Couplings
About Shaft Couplings Including: Bellows Couplings, Drive Shafts, Flexible Couplings, Flexible Shaft Couplings, Fluid Coupling, Flywheel Coupling, Gear Couplings, Jaw Couplings, Motor Couplings, Oldham Couplings, Torque Limiters & Universal Joints.
Flexible Shaft Couplings provide mechanical power in the form of torque to pieces of rotary equipment. Shafts, such as drive shafts and line shafts, are used to provide rotary motion to a wide spectrum of vehicles and equipment, and shaft couplings are key to providing secure rigid, flexible or non-linear connection between shafts, wheels and rotary equipment. Manufacturers utilize shaft couplings to connect rotary equipment such as power transmissions, drive shafts, line shafts, generators, wheels, pumps and turbines in a variety of automotive, oil and gas, aerospace, water/waste treatment and construction industries. Rigid shaft couplings connect well-aligned shafts linearly. Fluid couplings transmit energy through oil by a pump and turbine construction. Flexible couplings such as bellows couplings connect shafts and equipment which require misalignment flexibility or non-linear alignment. Gear couplings transfer rotary motion at a 90 degree angle, while universal joints work similarly, connecting shafts with a joint which allows a full range of motion. Motor couplings like flywheel couplings and torque limiters are types of flexible couplings that are found in transmissions and motors of many different vehicles. Jaw couplings offer zero backlash and provide the best vibration dampening.
Shafts aid in positioning equipment and supplying it with an axis of rotation; engineers mount rotary equipment - such as wheels - upon rigid or linear shafts, using shaft couplings to connect the shafts of rotating equipment in order to allow some axial and angular misalignment while maintaining torque power. In certain industrial applications, shafts remain aligned with one another continuously, in which case rigid shaft couplings remain an effective choice. A commonly used rigid shaft is the drive shaft, which transfers power from a car, truck or motorcycle's transmission to its wheels. Universal joints, which are also found in drive shafts in automobiles, connect shafts in a way that allows the shaft to rotate and bend while still providing torque. Used in similar applications, gear couplings connect shafts while simultaneously providing torque. Gear couplings are identical in design to sprockets, using a gearhead in the same way sprockets move chains. Shafts and equipment which require a wider range of motion use universal joints or gear couplings.
During operation, some types of shafts tend to shift, causing misalignment. In applications in which shaft misalignment is common, manufacturers use flexible shaft couplings such as bellows couplings. Flexible shaft couplings provide efficient accommodation for moderate shaft misalignment. Shaft misalignment occurs when the shafts' axes of rotation become skewed. Movement, bumps or vibration cause shaft movement, which results in parallel, angular or skewed shaft misalignment. Parallel misalignment occurs when shafts' axes are parallel to one another, but do not intersect with one another; angular misalignment occurs when the axes of shafts intersect with one another at an angle, and skewed misalignment occurs when axial and angular misalignment occur in conjunction with one another. Flexible shaft couplings provide the means by which rotating equipment can continue to function during moderate displacement measuring up to 5° of misalignment. In addition to transmitting torque and accommodating shaft misalignment, flexible shaft couplings perform other functions. Flexible shaft couplings accommodate axial displacement, also called end float, which occurs when the shafts move along the axis of rotation, either toward or away from one another. Flexible shaft couplings also provide shock absorption and lessen the intensity of vibrations, a process known as damping.
Shaft coupling manufacturers fabricate couplings for a broad range of applications, often specializing in certain flexible applications, automotive applications, linear applications or industry-specific equipment applications. Correct flexible coupling requires careful analysis of the industrial application and environment in which the coupling will be used, as well as the performance of individual couplings. Flexible shaft couplings are categorized according to their means of flexibility and their application into three main categories: mechanical flexible shaft couplings, elastomeric flexible shaft couplings, and metallic membrane flexible shaft couplings. Not all coupling manufacturers fabricate all types of flexible couplings; some specialize instead in gear couplings, bellows couplings and other industry-specific types. Many coupling manufacturers also manufacture various types of shafts, such as drive shafts, line shafts and bearing supported stub shafts, offering custom fabrication for unusual coupling applications.
Shaft Coupling Types
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offer several advantages, which include efficient torque transmission,
high overload tolerance and high torsional stiffness. Compression couplings
include jaw couplings, pin and bush couplings and donut couplings.
- permit angular misalignment, but only a small
degree of axial motion. A sub-type of metallic membrane coupling.
- accommodate angular misalignment, but do not accommodate
parallel misalignment or axial motion. A sub-type of metallic membrane
coupling.
- transmit torque from engines to moving parts.
-
contain a resilient element, such as rubber or plastic. Elastomeric
couplings possess many advantages, including a high damping ability,
high shock absorption, a high degree of misalignment accommodation,
and do not require lubrication; however, elastomeric couplings are larger
than metallic couplings, and possess sensitivity to ultraviolet light,
chemicals and high temperatures.
-
are designed to continue operating for a certain length of time after
the application of torque has ceased.
- transmit power while compensating for any misalignment.
- accommodate moderate shaft misalignment while transferring power.
-
offer efficient torque transmission in a compact mechanism, and permit
a high degree of axial movement. However, gear couplings require piloting,
and may malfunction at very high or very low torques.
-
offer adequate vibration damping and shock absorption. However, significant
axial movement may compromise coupling resilience.
- obtain flexibility through loosely fitted parts that
move past one another. Mechanical flexible couplings maintain high torsional
stiffness and accommodate a high degree of angular misalignment; however,
mechanical couplings require lubrication and maintenance, and may not
permit adequate axial movement.
- do not contain a rubber or a plastic element. Metallic flexible
couplings offer high torsional stiffness and great resistance to chemicals,
ultraviolet radiation and high temperatures.
- obtain flexibility through the bending
of a membrane within the coupling. Metallic membrane couplings require
low maintenance and no lubrication; however, these couplings may be
more expensive than mechanical flexible couplings.
-
provide a high degree of misalignment accommodation, produce low reactionary
loads and offer high torsional softness. Shear couplings include tire,
sleeve and molded-element couplings.
- are hinges that enable rigid rods to bend.
Shaft Coupling Terms
- The condition in which the axes of shafts intersect with one another
at an angle; angular misalignment is calculated by measuring the angle
at the intersection of the connected axes, expressed in degrees.
- An imaginary line in the center of an object
around which the object rotates.
- Characterized by movement along the axis of rotation.
- Condition in which shaft's move axially; also
called end float.
- The amount of movement along the shaft axes that
a coupling can permit.
- The change in a shafts length, whether an increase
or decrease in length, upon the application of a load.
- The extent of shaft movement.
- Measurement indicating the comparison of
flexibility between shafts.
- The shaft's resistance to the application
of torque.
- The hole on the shaft onto which the coupling is mounted.
- The pressure at which a device fails and loses
ability to retain fluid.
- The reduction of vibration between shafts; this reduction
is caused by an elastomer in the coupling.
- In such cases the entire coupling does not have
to be replaced and only certain components are repaired on site of the
coupling.
- Measurement
unit indicating the time rate of work a piece of equipment produces. With
regard to mechanical power, horsepower equals the movement of 33,000 pounds
one foot per minute or the movement of 550 pounds one foot per second.
Horsepower equals 746 watts of electrical power.
- A delay in the response of an object to forces, especially
magnetic forces, acting upon the object; often observed in elastic and
magnetic objects.
- Balance of
the coupling found in the original design of the coupling itself. This
also can be a factor of the materials used in construction of the coupling,
as certain stocks of metal are better for equilibrium.
- Rectangular opening in the coupling bore in which a key
may be inserted to lock couplings and shaft parts into place.
- The condition in which shafts axes are
parallel, but do not intersect with one another; also called parallel
offset or radial misalignment.
- The process of guaranteeing that shafts and couplings
maintain the same axis of rotation.
- The coupling's
exertion of force upon shafts during parallel misalignment, which causes
the shafts to bend.
-
Measurement of operating speed indicating the number of full rotations
a shaft completes in one minute.
- A protective pin used in some couplings to prevent
cut off.
- An optional
bolt found on some flexible couplings, which are used during high speed
applications. Installed with a socket wrench.
- Lengthening
of shafting caused by change in environmental temperature.
- The measurement of the extent to which a force applied
to an object causes the object to rotate.
- The low
resistance of a shaft to twisting motion, opposite of torsional stiffness.
- The measurement of a shaft's resistance
to twisting during operation. High torsionsal stiffness indicates minimal
shaft twisting; low torsional stiffness indicates little resistance to
twisting.
- The change in a rotational system's
torque.