Composite bearing

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A composite bearing is a bearing made from a combination of materials such as a resin reinforced with fibre and this may also include friction reducing lubricants and ingredients.

Contents

A composite bearing is not a polytetrafluoroethylene (PTFE) bearing in a carrier of another material, this is a PTFE bearing in a carrier. The plain composite bearing can be lighter than a rolling element bearing but this is not always a feature as some composites are extremely dense which results in lower porosity. Another distinctive feature of the composite bearing is its lightweight design—it can be one-tenth the weight of the traditional rolling element bearing. [1] No heavy metals are used in its manufacture. [2]

Composite bearings can be customized to meet the individual requirements of many applications, such as wear- or high-temperature resistance. The weight of the composite bearing can vary depending on its backing. The PTFE liner can be applied on steel or aluminum backing. Through filler compounds, various properties of the composite bearing, such as resistance to creep, wear and electrical conductivity, can be optimized.

Technology

A composite bearing is a bearing made from a composite material, such as fibre reinforced resin, or plastic. These will often contain friction reducing ingredients such as PTFE but this is not the only material for reducing friction and wear and lubricating when the bearing is running dry (without external lubricants). PTFE in itself is not a good bearing material as it is inherently soft and deforms under pressure, so the use of PTFE as a liner is not as beneficial as having PTFE combined into a solid and strong matrix of resin and fibre. [3] A composite bearing is a bearing with a liner of PTFE compound and a metal backing. PTFE is a fluorocarbon solid, as it is a high-molecular-weight compound consisting wholly of carbon and fluorine. PTFE is hydrophobic: neither water nor water-containing substances wet PTFE. Components engineered with PTFE offer consistent, controlled friction over their lifetime. [4]

PTFE is often used as a non-stick coating for pans and other cookware. It is very non-reactive, partly because of the strength of carbon-fluorine bonds, so it is often used in containers and pipe work for reactive and corrosive chemicals. PTFE can also be used as a machinery lubricant to reduce friction, wear and energy consumption.

PTFE is self-lubricating, so wet lubrication and replenishment of lubrication is not necessary but can be added if a reduction of the coefficient of friction or wear is demanded depending on the application.

Application and uses

Automotive

Automotive manufacturers are striving to meet growing demand for lighter and more fuel-efficient vehicles [5] and evaluate components and materials used in various car applications. Composite bearings are useful components in automotive design and are used in a range of applications throughout the car, from the powertrain to the car interior. In addition to enhancing automotive performance, composite bearings’ split ring design allows them to be press fitted, without the need for adhesive or excessive assembly force.

Steering Yoke

The steering rack has a bearing situated at the yoke - the interface between the steering rack and the steering column. The yoke is designed to prevent the separation of the steering rack from the steering column, whilst allowing the steering rack to move freely the in transverse direction. The yoke determines a motorist's ability to feel the road surface and the vehicle's maneuverability. With their PTFE liner, composite bearings reduce friction in the steering yoke. [6]

Belt Tensioner

A belt tensioner is a device designed to maintain tension in the engine's timing belt. There is a spring device in the belt tensioner where the bearing is located. The spring device oscillates back and forth at 2° for about 60 cycles per minute.

Composite bearings ensure an appropriate and consistent level of torque and damping to maintain the correct tension in the drive belt while the engine is in operation.

Door Hinges

In door hinges, bearings sit between the hinge pin and housing to ensure smooth movement of the door when it is opened and closed by passengers. Composite bearings are used in a number of automotive hinge systems due to their durability under high loads and corrosion resistance. [6]

Bearings also play a role in obtaining a quality paint finish on the car. Composite bearings’ PTFE compound liners are conductive and can transfer electricity to the hinges to facilitate the electrostatic painting process.

They are also hydrophobic and repel paint, minimizing the risk of excess droplets impairing the paintwork finish.

Seat Mechanism

In adjustable seats, seat mechanisms facilitate movement. A bearing fits between the linkage and the pin and is designed to provide correct levels of torque. Composite bearings can be used in the pivot points in seat components to maintain torque, allowing passengers to adjust their seat easily and smoothly for a comfortable experience.

Bicycle

Bicycle designers strive to reduce weight and increase the performance of their bicycles without sacrificing quality and strength. The bicycle industry is demanding lightweight, high-performance products with maintenance-free components. [7]

Fork

The bicycle fork enhances rider comfort in rough terrain by enabling the shaft attached to the bicycle frame to slide within the housing attached to the wheels. The bearing sits between the shaft and housing. The liner of PTFE within composite bearings enhances shock absorption as it acts as a cushion, while the lightweight metal backing helps to reduce bicycle weight. [8]

Shock Absorbers

Front shocks, key components in suspension bicycles, are designed to reduce the impact of bumps and jolts for a smoother ride. The bearing sits between the inner shaft and outer housing to facilitate smooth movement in the mechanism for optimum performance. Composite bearings with a PTFE liner act as a cushion, absorbing excess vibrations to further enhance the movement.

Headsets

Composite bearings can be used in the headset. [8] [9] Composite bearing can be lightweight to support weight reduction efforts across the overall bicycle. [8]

Pedal and Brake Pivots

The low friction that bearings can provide helps to reduce “stick slip”, avoiding any undesirable jerking motion. Pedals rotate on bearings that connect the spindle to the end of the crank and the body of the pedal. [8]

Derailleurs

The derailleur is used in the bicycle's gear system. The change in cable tension to switch gears moves a chain from side to side, "derailing" the chain onto different sprockets and, therefore, different gears. [8] [10]

Solar

Solar has become a viable source of energy. According to the International Energy Agency, Concentrated Solar Power (CSP) could be responsible for up to 11.5% of global electricity production by 2050. [11] The life expectancy of the CSP plant could be up to 40 years (13)and energy companies are looking for components that will last the lifetime of the CSP plant.

Solar Tracking System

Concentrating Solar Power (CSP) plants use concentrated solar radiation as a high-temperature energy source to produce electrical power. A solar tracker is a device for concentrating solar reflectors toward the sun. Bearings are used in the pivot points to both support the structure in a parabolic trough and to rotate the mirrors on heliostats (solar tower).

Composite bearings can be used in the parabolic trough and solar power tower to rotate the mirrors. They can withstand the loads in CSP applications, are weather and corrosion resistant and also offer low and constant friction (no stick-slip effect) over the mechanism's life cycle.

Piston Pumps in off-highway Construction Equipment

Off-highway construction equipment from excavators to simple loaders employs hydraulic transmission systems as a primary source of motion. Hydraulic piston pumps, mechanical devices used to convert mechanical energy into hydraulic energy, are typically used in off-highway construction equipment and driven by an electric motor or a combustion engine.

Bearings are mounted on the piston pump shaft, which transfers drive torque to the cylinder block. The bearing's role is to ensure smooth movement and reduce energy use. Composite bearings’ self-lubricating PTFE layer allows consistent, low friction in pump mechanisms for minimal energy use and reduced maintenance requirements.

See also

Related Research Articles

A lubricant is a substance that helps to reduce friction between surfaces in mutual contact, which ultimately reduces the heat generated when the surfaces move. It may also have the function of transmitting forces, transporting foreign particles, or heating or cooling the surfaces. The property of reducing friction is known as lubricity.

<span class="mw-page-title-main">Polytetrafluoroethylene</span> Synthetic polymer

Polytetrafluoroethylene (PTFE) is a synthetic fluoropolymer of tetrafluoroethylene and is a PFAS that has numerous applications. The commonly known brand name of PTFE-based composition is Teflon by Chemours, a spin-off from DuPont, which originally discovered the compound in 1938.

<span class="mw-page-title-main">Ball bearing</span> Type of rolling-element bearing

A ball bearing is a type of rolling-element bearing that uses balls to maintain the separation between the bearing races.

<span class="mw-page-title-main">Bearing (mechanical)</span> Mechanism to constrain relative movement to the desired motion and reduce friction

A bearing is a machine element that constrains relative motion to only the desired motion and reduces friction between moving parts. The design of the bearing may, for example, provide for free linear movement of the moving part or for free rotation around a fixed axis; or, it may prevent a motion by controlling the vectors of normal forces that bear on the moving parts. Most bearings facilitate the desired motion by minimizing friction. Bearings are classified broadly according to the type of operation, the motions allowed, or the directions of the loads (forces) applied to the parts.

<span class="mw-page-title-main">Plain bearing</span> Simplest type of bearing, comprising just a bearing surface and no rolling elements

A plain bearing, or more commonly sliding contact bearing and slide bearing, is the simplest type of bearing, comprising just a bearing surface and no rolling elements. Therefore, the journal slides over the bearing surface. The simplest example of a plain bearing is a shaft rotating in a hole. A simple linear bearing can be a pair of flat surfaces designed to allow motion; e.g., a drawer and the slides it rests on or the ways on the bed of a lathe.

<span class="mw-page-title-main">Flexure bearing</span> Type of mechanical bearing

A flexure bearing is a category of flexure which is engineered to be compliant in one or more angular degrees of freedom. Flexure bearings are often part of compliant mechanisms. Flexure bearings serve much of the same function as conventional bearings or hinges in applications which require angular compliance. However, flexures require no lubrication and exhibit very low or no friction.

<span class="mw-page-title-main">Jewel bearing</span> Jewel-lined bearing used in precision instruments, particularly mechanical watches

A jewel bearing is a plain bearing in which a metal spindle turns in a jewel-lined pivot hole. The hole is typically shaped like a torus and is slightly larger than the shaft diameter. The jewels are typically made from the mineral corundum, usually either synthetic sapphire or synthetic ruby. Jewel bearings are used in precision instruments where low friction, long life, and dimensional accuracy are important. Their main use is in mechanical watches.

<span class="mw-page-title-main">Rolling-element bearing</span> Bearing which carries a load with rolling elements placed between two grooved rings

In mechanical engineering, a rolling-element bearing, also known as a rolling bearing, is a bearing which carries a load by placing rolling elements between two concentric, grooved rings called races. The relative motion of the races causes the rolling elements to roll with very little rolling resistance and with little sliding.

<span class="mw-page-title-main">Constant-velocity joint</span> Mechanisms for smoothly transmitting rotation through a bend in a drive shaft

A constant-velocity joint is a mechanical coupling which allows the shafts to rotate freely and compensates for the angle between the two shafts, within a certain range, to maintain the same velocity.

<span class="mw-page-title-main">Rolling resistance</span> Force resisting the motion when a body rolls on a surface

Rolling resistance, sometimes called rolling friction or rolling drag, is the force resisting the motion when a body rolls on a surface. It is mainly caused by non-elastic effects; that is, not all the energy needed for deformation of the wheel, roadbed, etc., is recovered when the pressure is removed. Two forms of this are hysteresis losses, and permanent (plastic) deformation of the object or the surface. Note that the slippage between the wheel and the surface also results in energy dissipation. Although some researchers have included this term in rolling resistance, some suggest that this dissipation term should be treated separately from rolling resistance because it is due to the applied torque to the wheel and the resultant slip between the wheel and ground, which is called slip loss or slip resistance. In addition, only the so-called slip resistance involves friction, therefore the name "rolling friction" is to an extent a misnomer.

<span class="mw-page-title-main">Steering damper</span> Device that helps dampen your steering from side to side

Originally designed in 1966 by Leonard R Jordan Jr, the steering damper or steering stabiliser is a damping device designed to inhibit an undesirable, uncontrolled movement or oscillation of a vehicle steering mechanism, a phenomenon known in motorcycling as the death wobble. The stabilizer absorbs unwanted energy in the side to side motion allowing the forks and shocks to work properly. Many things can cause a motorcycle chassis to get upset such as slamming on brakes, rough road, and lastly improper setup. An upset chassis can be a great deal of danger for the rider often times resulting in a crash. A steering stabilizer slows those movements down resulting in the rider feeling more comfortable on the motorcycle.

Dry lubricants or solid lubricants are materials that, despite being in the solid phase, are able to reduce friction between two surfaces sliding against each other without the need for a liquid oil medium.

The exoskeletal engine (ESE) is a concept in turbomachinery design. Current gas turbine engines have central rotating shafts and fan-discs and are constructed mostly from heavy metals. They require lubricated bearings and need extensive cooling for hot components. They are also subject to severe imbalance that could wipe out the whole rotor stage, are prone to high- and low-cycle fatigue, and subject to catastrophic failure due to disc bursts from high tensile loads, consequently requiring heavy containment devices. To address these limitations, the ESE concept turns the conventional configuration inside-out and utilizes a drum-type rotor design for the turbomachinery in which the rotor blades are attached to the inside of a rotating drum instead of radially outwards from a shaft and discs. Multiple drum rotors could be used in a multi-spool design.

In mechanical engineering, a cam follower, also known as a track follower, is a specialized type of roller or needle bearing designed to follow cam lobe profiles. Cam followers come in a vast array of different configurations, however the most defining characteristic is how the cam follower mounts to its mating part; stud style cam followers use a stud while the yoke style has a hole through the middle.

<span class="mw-page-title-main">Yaw system</span>

The yaw system of wind turbines is the component responsible for the orientation of the wind turbine rotor towards the wind.

<span class="mw-page-title-main">Yaw bearing</span>

The yaw bearing is the most crucial and cost intensive component of a yaw system found on modern horizontal axis wind turbines. The yaw bearing must cope with enormous static and dynamic loads and moments during the wind turbine operation, and provide smooth rotation characteristics for the orientation of the nacelle under all weather conditions. It has also to be corrosion and wear resistant and extremely long lasting. It should last for the service life of the wind turbine) while being cost effective.

<span class="mw-page-title-main">GGB (company)</span>

GGB manufactures self-lubricating, prelubricated plain bearings and tribological polymer coating for various industries and applications. It has production facilities in the U.S., Germany, France, Slovakia, Brazil and China.

<span class="mw-page-title-main">Air bearing</span>

Air bearings are bearings that use a thin film of pressurized gas to provide a low friction load-bearing interface between surfaces. The two surfaces do not touch, thus avoiding the traditional bearing-related problems of friction, wear, particulates, and lubricant handling, and offer distinct advantages in precision positioning, such as lacking backlash and static friction, as well as in high-speed applications. Space craft simulators now most often use air bearings and 3-D printers are now used to make air-bearing-based attitude simulators for CubeSat satellites.

A tolerance ring is a radially sprung ring that is press fitted between two mating components to act as a frictional fastener. They are flexible shims designed to fix two cylindrical parts together. The wavelike protrusions that run around the circumference of the ring generate a retention force to provide an optimal fit between the two mating components without the need for adhesive or excessive assembly force, simplifying the process for manufacturers. They allow for any misalignment caused by thermal expansion or excessive vibration. Tolerance rings can be used as bearing mounts and as a means of dealing with torque transfer, torque overload protection and axial slip between mating components. They are often used to isolate undesirable vibration in engines and electric motors, for noise-free mechanism operation in passenger vehicles and domestic appliances, where noise reduction has become a major trend in recent years. Modifications to tolerance rings can be made to tune the dynamic stiffness and, therefore, the frequencies that can be isolated.

Pitch bearing Component connecting a turbine blade to the hub allowing pitch variation

The pitch bearing, also named blade bearing, is a component of modern wind turbines which connect the rotor hub and the rotor blade. The bearing allows the required oscillation to control the loads and power of the wind turbine. The pitch system brings the blade to the desired position by adapting the aerodynamic angle of attack. The pitch system is also used for emergency breaks of the turbine system.

References

  1. ↑ "Saint-Gobain and Norco Get Celebrity Thumbs-Up". Product Design and Development. 2012-06-01. Archived from the original on 2016-08-19. Retrieved 2016-05-12.
  2. ↑ "A sunny future: how Small bearings can make a huge difference in concentrated solar plants (2011)" (PDF). Sustainability Outlook: 35–36. Retrieved 12 May 2016.[ permanent dead link ]
  3. ↑ Sliney, H. E.; Jacobson, T. P. (January 1975). "Performance of graphite fiber-reinforced polyimide composites in self-aligning plain bearings to 315 C".
  4. ↑ "Saint-Gobain Components Drive Advances in Automotive Friction Control and Manufacturing Performance" (PDF). Industrial Products Purchase. Archived from the original (PDF) on 13 March 2013. Retrieved 12 May 2016.
  5. ↑ "Fuel Economy and CO2 Emissions Standards, Manufacturer Pricing Strategies, and Feebates" (PDF). Oak Ridge National Laboratory. Retrieved 9 June 2016.
  6. 1 2 "Enhancing Automotive OEMs". Bearings. 14 June 2012. Retrieved 9 June 2016.
  7. ↑ "Eurobike 2012: Featherweight dream bikes from Stevens and AX Lightness". Road Cycling UK. Retrieved 2016-06-09.
  8. 1 2 3 4 5 "Key Applications of Norglide Composite Bearings & Norslide Cable Liners in High-Performance Bicycles | Product Showcase". showcase.designnews.com. Archived from the original on 2016-08-07. Retrieved 2016-06-09.
  9. ↑ Publishing, Seattle. "Bicycle Paper.com :: News :: Riding Circles Around Old Standards". www.bicyclepaper.com. Archived from the original on 2016-06-25. Retrieved 2016-06-09.
  10. ↑ "Saint-Gobain shows Norglide off at Taipei Cycle Show". Bikebiz. Archived from the original on 2016-08-16. Retrieved 2016-06-09.
  11. ↑ "Publications" (PDF). www.iea.org. Archived from the original (PDF) on 2017-07-07. Retrieved 2016-06-09.
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