What is the definition of "friction lining"?
A lining applied to friction clutches and brakes to reduce heat and wear caused by contact between mating surfaces. Abestos was once commonly used, but today other materials are being used, such as cotton and rubber.

Learn more about friction lining in the class Clutch and Brake Applications 250 below.


Mechanical Systems Training


Class Information
Mechanical Systems Training Tooling U-SME classes are offered at the beginner, intermediate, and advanced levels. The typical class consists of 12 to 25 lessons and will take approximately one hour to complete.
Class Name:Clutch and Brake Applications 250
Description:This class describes different types of clutches and brakes, the operating conditions in which they are used, and installation, maintenance, and safety concerns.
Prerequisites: 560100  560110  560120 
Difficulty:Intermediate
Number of Lessons:18
Language:English, Spanish
 
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Class Outline
  • Objectives
  • What Are Clutches and Brakes?
  • Clutch and Brake Design
  • Types of Clutch and Brake Actuation
  • Friction Clutch and Brake Systems
  • Disk Clutches
  • Disk Brakes
  • Expanding Drum Clutches and Brakes
  • Contracting Drum Clutches and Brakes
  • Cone Clutches and Brakes
  • Band Clutches and Brakes
  • Positive Clutches
  • Electromagnetic Clutches and Brakes
  • Clutch and Brake Materials
  • Inspecting and Maintaining Clutches and Brakes
  • Installing and Repairing Clutches and Brakes
  • Safety for Clutches and Brakes
  • Summary
  
Class Objectives
  • Describe characteristics shared by clutches and brakes.
  • Identify factors affecting clutch and brake design.
  • Distinguish between types of clutch and brake actuation.
  • Describe friction clutch and brake systems.
  • Describe disk clutches.
  • Describe disk brakes.
  • Describe expanding drum clutches and brakes.
  • Describe contracting drum clutches and brakes.
  • Describe cone clutches and brakes.
  • Describe band clutches and brakes
  • Describe positive clutches.
  • Describe electromagnetic clutches and brakes.
  • Distinguish between materials used in clutch and brake design.
  • Describe how to recognize clutch and brake failure.
  • List factors in proper clutch and brake installation.
  • Identify safety hazards for working with clutches and brakes.

Class Vocabulary

Vocabulary TermDefinition
actuation The energy and power source used to operate and engage a mechanical device. Clutch and brake assemblies may be actuated purely mechanically, or with some or all of their power coming from hydraulic, pneumatic, or electric sources.
asbestos A fibrous, heat-resistant material once widely used in the linings of friction clutches and brakes, along with many other applications. Abestos is a known health risk, and OSHA has established guidelines for installing, removing, and maintaining clutches and brakes containing it.
axial force A force applied parallel to the centerline of a shaft.
band brake A simple friction brake consisting of a flexible, anti-friction lined band wrapped around a rotating drum. Band brakes are used in hoists.
band clutch A simple friction clutch consisting of a flexible, anti-friction lined band wrapped around a rotating drum. Band clutches are not commonly used.
brake A specific type of clutch that slows and stops motion by engaging a rotating shaft and a fixed component.
brake fade A reduction in braking effectiveness caused by excessive heat and wearing of components.
brake fluid Hydraulic fluid used in some brake designs. When disk brakes are applied, the hydraulic fluid is sent through the brake lines to the pressure plate or caliper to apply pressure to the rotor and slow or stop motion.
brake pad The anti-friction material that lines plates and calipers used in disk brakes. Brake pads help to reduce heat and increase the life span of braking elements.
caliper A component in disk brakes that holds brake pads and straddles the rotor, pressing against it when the brake is applied to slow and stop motion. Disk brakes with calipers do not create as much heat as brakes with a friction plate.
cam A low-friction, circular lever consisting of a lobe and a shaft that transforms circular motion into linear motion. Cams are sometimes used in hydraulically actuated clutch and brake systems.
cantilever brake A friction brake featuring two separate arms located on each side of a bicycle rim. The cantilever brake is actuated by pressing a hand lever located on the handlebars.
cast iron A metal consisting of iron, over 2.11% carbon, and 1 to 3% silicon offering heat resistance and compressive strength. Cast iron is often used in clutches and brakes.
centrifugal force A force that attempts to pull an object traveling in a cylindrical path away from the center of rotation.
clutch A device that controls the transfer of power between machine components by engaging and disengaging two rotating shafts.
clutch-brake assembly A unit that combines both clutching and braking capabilities. Disk and drum styles may combine both functions and are used in heavy machinery.
coil spring A type of spring formed by winding strips of metal around a cylinder or cone to create a helical or conical shape. Coil springs are used to assist in various types of actuation for clutch and brake systems.
cone brake A friction brake consisting of a cone that fits inside a cup when engaged. Cone brakes are less expensive than disk styles but can be difficult to disengage.
cone clutch A friction clutch consisting of a cone that fits inside a cup when engaged. Cone clutches are less expensive than disk styles but can be difficult to disengage.
contaminant Damaging foreign material such as dirt or shop debris that causes wear to machine components.
contamination Damage occurring when foreign materials such as dirt enter a clutch or brake system and cause uneven wear.
contracting drum brake A friction brake that slows or stops motion when shoes contract and make contact with the outer surface of a rim or drum. Contracting rim brakes are widely used in mining and marine applications.
contracting drum clutch A friction clutch that transfers torque when shoes contract and make contact with the outer surface or a rim or drum. Contacting rim clutches are widely used in mining and marine applications.
corrosion The gradual chemical attack on a material by atmosphere, moisture, or other agents.
cycling rate The amount of time needed for a clutch or brake to go through a cycle of engagement and disengagement, and how quickly it can begin a new cycle.
disk brake A friction brake that stops motion when a stationary element is pressed against a rotating disk. Disk brakes are commonly used in automobiles and in some industrial machinery, especially in older machines.
disk clutch A friction clutch that transmits torque when rotating disks are pressed together. Disk clutches are commonly used in automobiles with manual transmissions.
double disk A friction clutch or brake assembly consisting of two drive and driven disks. The double disk design produces more torque and braking force than the single disk design.
downtime Unproductive blocks of time during which machine operations cease, often due to mechanical problems.
drive disk The disk in a disk clutch or brake system that receives energy from a power source, such as an electric motor. Drive disks are also called input disks and transmit torque to a driven disk connected to an output component, such as a transmission.
driven disk The disk that receives energy from the drive disk in a disk clutch or brake system. Driven disks are connected to components such as transmissions or other output devices.
dry operation Operation that occurs without lubrication. Dry operation provides the greatest amount of torque or braking force but also generates heat and increases wear.
eddy current clutch and brake An electromagnetic style of clutch and brake offering excellent control in braking and clutching but greater heat generation than other electromagnetic types.
electric actuation Actuation initiated by electric currents from an electric motor. Electric actuation offers fast cycle rates, quick response times, and remote operation but provides less force than hydraulic actuation and produces considerable heat.
electromagnetic brake A non-contact brake design actuated when an electric current charges a coil that acts as an electromagnet. Electromagnetic brakes are widely used in automated machinery and provide a high cycling rate.
electromagnetic clutch A non-contact clutch design actuated when an electric current charges a coil that acts as an electromagnet. Electromagnetic clutches are used in some automated machinery and provide a high cycling rate.
expanding drum brake A friction brake that slows or stops motion when shoes expand and make contact with the inner surface of a rim or drum. Expanding drum brakes are also called internal shoe brakes.
expanding drum clutch A friction clutch that transfers torque when shoes expand and make contact with the inner surface or a rim or drum. Expanding rim clutches are widely used in mining and marine applications.
friction The resistance to motion between the contact surfaces of two objects. Friction generates heat and increases the wear between components but is the key to providing clutching and braking forces.
friction clutch and brake system An assembly of components containing two surfaces that press together and transfer energy through friction to provide torque or prevent motion. Friction clutches and brakes are the most common type available and include disk and drum styles.
friction lining A lining applied to friction clutches and brakes to reduce heat and wear caused by contact between mating surfaces. Abestos was once commonly used, but today other materials are being used, such as cotton and rubber.
friction plate A stationary disk used in disk brakes to apply pressure to the rotor and slow and stop motion.
heat cracks Visible damage to clutches and brakes caused by thermal fatigue.
High Efficiency Particulate Air Filter A disposable dry filter encased in metal or cardboard, often abbreviated as HEPA. The filter is normally paper and is regulated to extract at least 99.97% of dangerous particles, such as asbestos, from the air.
hydraulic actuation Actuation initiated by pressurized fluids. Hydraulic actuation is used when a great deal of torque or braking force is required.
hysteresis clutch and brake An electromagnetic style of clutch and brake offering a very long service life and precise control in applications requiring slip, such as in coiling.
inner drum The cylindrical component nested inside the outer drum in a drum-style friction clutch or brake. Depending on the style, shoes located on the inner drum may expand and engage the outer drum, or pressure may be applied from the outer drum to the outside surface of the inner drum during actuation.
input shaft The shaft connecting the prime mover to the driving element, such as a drive disk, in a clutch system.
kinetic energy Energy of an object that has been put in motion.
kPa Kilopascals. A metric unit used to measure pressure. 1 Kilopascal equals 1000 pascals, and approximately 0.1450 psi.
lever A simple machine consisting of a rigid bar that pivots about a fulcrum. Levers are used to transmit motion and alter mechanical advantage.
linkage system A system of cables or rods that transmits power or motion from an input to an output component. Disk clutch and brakes require a linkage system.
lockout device A device that uses positive means such as a lock and key or combination lock to hold an energy-isolating mechanism in a safe position and prevent equipment or machinery from being energized.
lockout/tagout A method of protecting employees from accidental machine startup through proper locking and labeling of machines that are undergoing maintenance.
mechanical actuation Actuation caused by the physical movement of components when an operator applies force using levers, pedals, and other devices. Mechanical actuation is inexpensive but offers limited force and slower cycling rates and response times.
mechanical force Force created by the movement of an object over a distance.
molded lining A general purpose friction lining used in clutches and brakes. Molded linings are inexpensive but cannot operate in high-friction operations.
multiple disk A friction clutch or brake assembly consisting of multiple drive and driven disks. The multiple disk design produces more torque and braking force than single or double disk designs.
multiple tooth clutch A cylindrical clutch containing a series of small tooth-like projections around a perimeter. The multiple-tooth clutch is used in some slow-speed industrial equipment requiring a large torque-carrying capacity.
OSHA The Occupational Safety and Health Administration. A government agency under the U.S. Dept. of Labor that helps employers reduce injuries, illnesses, and deaths in the workplace.
outer drum The outer cylindrical component surrounding the inner drum in a drum-style friction clutch or brake. Depending on the style, shoes located on the outer drum may engage the inner drum, or pressure may be applied from the inner drum to the inside surface of the outer drum during actuation.
output shaft In a clutch system, the shaft connecting the driven element, such as a disk, to the output component receiving torque, such as a transmission.
personal protective equipment Any example of various safety equipment that workers wear or use to prevent injury in the workplace. Safety glasses are common personal protective equipment (PPE).
piston A cylindrical component that moves up and down inside a mating hollow cylinder in response to a pressure change in pneumatic and hydraulic systems. Pistons may be used to transfer motion to clutch and brake components.
pneumatic actuation Actuation initiated by pressurized gas. Pneumatic actuation provides greater force than mechanical actuation and produces very little heat.
positive clutch A clutch that consists of two mating surfaces with interconnecting elements, such as teeth, that lock together during engagement to prevent slipping. Positive clutches are also known as mechanical lockup clutches.
power assist A means of lessening the amount of human force needed to depress brakes used in vehicles and other equipment. The assist can be provided by hydraulic means or by an air vacuum created in the piston.
prime mover The device that introduces energy into a power transmission system and converts the energy into the appropriate form.
psi Pounds per Square Inch. A unit in the English measuring system used to measure pressure. One psi equals approximately 6.8948 kilopascals.
race A groove located on the inside of a sprag clutch that provides a pathway for the rotating sprags.
response time The time needed for a clutch or brake to engage and perform the needed clutching or braking action.
rotor The driven, rotating disk in a disk brake that is stopped when pressure is applied by a stationary friction plate or by a caliper.
shoe Anti-friction material that lines metal plates in drum clutches and brakes. Shoes help to reduce heat and increase the life span of clutching and braking elements.
single disk A friction clutch or brake assembly consisting of a single drive and driven disk. The single disk design is the least expensive option but produces less torque and braking force than double and multi-disk systems.
sintered metal lining A friction lining made of metal powders heated, pressed, and molded together. Sintered metal linings provide the best resistance to heat and wear and are the most expensive choice.
slip clutch A friction clutch that temporarily disengages if it reaches a higher level of torque than it is designed to handle. The contracting drum clutch can be used as a slip clutch.
slipping A condition that occurs when the drive disk of a clutch fails to make complete contact with the driven disk, causing the driven disk to rotate at a different speed. In many operations, continuous slipping causes excessive wear and premature failure in the clutch system.
spiral claw clutch A positive clutch design featuring curved mating surfaces. The spiral claw clutch can operate in high speeds but in only one direction.
spline A flexible connection featuring grooves cut in a shaft that mate with corresponding grooves in a connecting member, such as a hub.
sprag A small, tapered element used in a sprag clutch that is similar to the roller in a roller bearing. Sprags rotate in races until motion in one direction causes sprags to wedge together and permit motion.
sprag clutch A one-directional positive clutch design that connects two shafts when motion causes rotating elements located within races to wedge together. Rotation in the opposite direction disconnects the input and output shaft.
square jaw clutch A positive clutch design featuring interlocking square teeth. The square jaw clutch is the least expensive type available and can be used only in low-speed applications.
tension brake A friction brake used in spooling and coiling that requires the brake to control tension by stopping and holding after allowing a small amount of material to advance.
thermal fatigue Damage caused by excessive heat or heat fluctuations over time. Thermal fatigue can cause heat cracks or brake fade in brakes or clutches and is caused by inappropriately high operating temperatures resulting from fast cycling rates or insufficient linings or mating materials.
torque A force causing rotation. Clutches provide torque.
transmission A machine that uses a combination of gears and other mechanical components to change the speed or torque of mechanical energy.
uniform wear The wearing away of the contact surfaces of friction clutches and brakes at the same rate across the entire surface. Disk, drum, and cone clutches and brakes experience uniform wear, while band clutches and brakes do not.
wear The gradual removal of material on a surface caused by contact and friction.
wet operation Operation that occurs with components submerged in oil or similar substances. Wet operation reduces heat and wear but also reduces the amount of torque and braking force available.
woven lining A friction lining providing greater flexibility than molded linings. Woven linings are more expensive than molded linings, but they provide better resistance to contamination and are widely used in band clutches and brakes.
wrap spring clutch A positive clutch design using a coil spring to link input and output shafts. Wrap spring clutches are often used in copy machines.