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The Ultimate Guide to Pillow Block Bearing
Pillow block bearing is one of the most common bearings in mechanical equipment. It consists of an inner ring, an outer ring, rollers, a cage and a seat. Among them, the inner and outer diameters of the inner ring and outer ring are different in size, which can bear axial load and radial load at the same time. Pillow block bearing is widely used in automobiles, mechanical equipment and other fields. Its main function is to support and reduce friction. Aubearing will use this blog to introduce the basics of pillow block bearing. Provide constructive suggestions to help you choose the right bearings.
Pillow block bearings are wear-resistant bearings contained within a solid cast iron, ductile iron or cast steel housing unit, also known as pillow block bearing units, which means they are self-contained, lubricated, sealed and can be installed in equipment superior. Mounted bearings are usually bolted to the surface so that the connected shaft is parallel to the surface. There are two types of bearing seats for pillow block bearings: integral bearing seats and split bearing seats. Solid pillow block bearing is a one-piece bearing seat, while split pillow block bearing is a two-piece bearing seat. The connection device can be a set screw, eccentric lock, single or double set ring, concentric lock or tapered adapter. Each type of pillow block bearing has its own advantages and disadvantages. Seals also vary, including gap seals, light contact seals, heavy contact seals and auxiliary seals. Choosing the proper mounting method and seals will extend bearing life. If installed correctly, pillow block bearings can last for many years without needing to be replaced.
Pillow block bearing is a type of bearing widely used in mechanical equipment. Pillow block bearings can be divided into multiple subcategories according to their load-bearing capacity and structural form, such as deep groove ball bearings, aligning ball bearings, angular contact ball bearings, etc. The structural feature of pillow block bearing is that the inner and outer spherical surfaces are in contact, and the balls are separated by a ball cage, so it has a certain load-bearing capacity and self-centering performance.
The function of pillow block bearing
Pillow block bearings do their job efficiently, keeping the outer ring of the bearing stationary while providing room for the inner ring to move. In addition, pillow block bearing also has the advantages of simple structure, easy disassembly, repair and maintenance. Surprisingly, installing this device does not require any special skills as its perfect structure makes it easier for users to install it on the surface of the case without any hassle. The two most important functions of pillow block bearing:
Supporting function: Pillow block bearing mainly ensures the normal operation of mechanical equipment by supporting the load of the working shaft. Its bearing capacity directly determines the load capacity of mechanical equipment, so the quality and performance of pillow block bearing affect the operating efficiency and lifespan of the entire mechanical system.
Reduce friction: During the operation of pillow block bearing, the roller can reduce the friction between the roller and the seat during the rolling process, thereby reducing energy loss. On the other hand, the cooperation between the inner ring of the pillow block bearing and the shaft can also reduce the wear and heat caused by friction and improve the efficiency and life of mechanical equipment.
Due to its excellent structural characteristics, pillow block bearing is widely used in various mechanical equipment, such as metallurgical equipment, mining equipment, water pumps, fans, machine tools and other fields. At the same time, pillow block bearing can also withstand certain radial and axial loads, so it is also commonly used in automobiles, motors and other industries.
Advantages and disadvantages of pillow block bearing
Pillow block bearing is a commonly used bearing unit; it is composed of a rolling bearing and a bearing seat. The outer surface of most outer rings of the rolling bearing used will be made into a spherical surface. It can be installed on the mechanical device through bolts. It has various structural forms, good versatility, interchangeability and centering functions. Its dual-structure sealing design also ensures operation in harsh environments.
self-aligning
The outer diameter of the pillow block bearing and the inner diameter of the bearing seat adopt a spherical matching method, with automatic alignment function, which can effectively compensate for errors such as axis misalignment and installation bottom surface deformation caused by installation.
Large load capacity
The internal structure of the pillow block bearing can be the same as the 6200 and 6300 series of deep groove ball bearings, so the FS seated outer spherical ball bearing can withstand radial load and a certain axial load. And the working noise is low.
long life
Pillow block bearings are usually used in harsh working environments such as mud, dust, moisture and high temperatures. The grease inside the bearing will deteriorate in a short period of time. Therefore, it is necessary to grease and re-lubricate the seated spherical ball bearings at appropriate intervals, and replace the deteriorated grease with fresh grease. FS cast iron outer spherical ball bearings are equipped with oil nozzles and can be re-lubricated, ensuring perfect performance and long service life in any working environment. Grease can be selected from normal temperature, low temperature and high temperature grease according to the ambient temperature of use. There is an oil groove on the outer ring of the bearing, which can better ensure that the grease can be smoothly injected into the bearing from the oil nozzle.
Excellent sealing performance
Both sides of the pillow block bearing are equipped with heat-resistant and oil-proof rubber sealing rings and steel plate dust covers for combined sealing. The dust cover is assembled on the outer diameter of the inner ring of the bearing and rotates together with the inner ring. It can effectively prevent external foreign matter from entering the inside of the bearing and protect the bearing against external pressure. This combined seal consisting of a sealing ring and a dust cover can prevent Mud, dust, and moisture enter the inside of the bearing, and at the same time, it prevents the grease inside the bearing from leaking out. This enables the bearings to maintain perfect working performance even in harsh working environments.
Sturdy bearing seat
The bearing seat has an integral seat structure. The bearing seat has excellent rigidity, which prevents the bearing from deforming during assembly. The bearing seat is durable under any working conditions. The bearing seat can be cast from gray cast iron, ductile iron, cast steel and other materials.
Easily locks onto the shaft
There are four ways to lock the bearing on the shaft. The commonly used method is to lock the two set screws on the extended end of the inner ring. You can also use an adapter sleeve, a locking sleeve or an eccentric sleeve to lock. These four methods can easily lock the bearing on the shaft.
heat treatment
The inner ring channel and the parts around it that need to be hardened are normally quenched, and the extended end of the inner ring where the set screw is mounted is partially tempered at high temperature to maintain toughness and impact resistance. After local high-temperature tempering around the screw holes in the inner ring, the bearing obtains better performance, which can prevent the screws from loosening during the operation of the bearing. At the same time, tightening the screws very tightly will not cause the inner ring to burst.
Prevent outer ring from rotating
The outer ring of the bearing is equipped with a unique stop ball. This stop pin allows the bearing to self-align and prevents the outer ring from rotating, extending the service life of the bearing.
Easy to install
The outer spherical ball bearing has been pre-injected with enough high-quality grease, and the seated outer spherical ball bearing can be installed directly on the shaft. This prevents harmful substances from entering the bearing during installation of the bearing unit.
Bearings and bearing seats are completely interchangeable
The bearings and bearing seats are precision machined, and the bearings and bearing seats are completely interchangeable, making it easy to replace the bearings at any time.
Different types of pillow block bearings
Pillow block bearing unit consists of a set of bearings and bearing seats. Most people say that the housing bearing unit is the same as the pillow block bearing, but in fact there are many designs of bearing units, and the pillow block bearing is the most widely used type of bearing unit on the market. According to the bearing type, there are ball bearing units, roller bearing units, and aligning ball bearing units; roller bearing units include spherical roller bearing units, tapered roller bearing units, needle roller bearing units; and sleeve bearing units. . According to different applications, there are different designs, such as high-temperature bearing units, stainless steel bearing units, high-speed bearing units, maintenance-free bearing units, ceramic bearing units, corrosion-resistant bearing units, etc.; bearing seat (pillar or vertical bearing seat) Includes designs for cast iron, ductile iron, heat-resistant plastics, stainless steel, ceramics and other diverse materials. The color of the bearing seat can be made into black, blue and green. There are several types of pillow block bearings available, each suitable for different applications. The most common types include:
A. ball bearings
Ball bearings are the most widely used type of pillow block bearing. They consist of an inner and outer ring with a set of balls in the middle. Ball bearings have low friction and high efficiency, making them ideal for applications requiring high-speed rotation.
B.Roller bearing
Roller bearings use cylindrical or tapered rollers instead of balls. They can handle heavier loads and are better suited for applications with higher shock and shock loads.
C. sleeve bearing
Sleeve bearings, also called plain bearings, rely on cylindrical sleeves rather than balls or rollers. They are cost-effective and suitable for low-speed applications where noise and vibration are not major issues.
Pillow block type
Bearing seats are generally cast. Commonly used bearing seats include vertical seat (P), square seat (F), boss square seat (FS), boss round seat (FC), diamond seat (FL), slider seat (T), narrow vertical seat Type seat (PA), high center vertical seat (PH), hanging bearing seat (FB), adjustable diamond seat (FA), etc.
Pillow block material options
How to Choose Pillow Block Bearings Pillow block bearings protect bearings during operation and provide a fixture for bearings in use. Bearing housings can be made from a variety of materials with different properties. The material the bearing is made of has a significant impact on the performance of the bearing unit.
Aluminum has high load-bearing capacity, fatigue strength and thermal conductivity.
Steel is a commercial iron with a carbon content of up to about 1.7%, making it an important alloying component. Malleable under the right conditions, distinguished from cast iron by its ductility and lower carbon content. Bearings are usually made of high carbon steel such as 52100.
Cast iron is made primarily of iron and contains important trace amounts of carbon and silicon. Cast iron is a natural composite material whose properties are determined by its microstructure, i.e. the stable and metastable phases formed during solidification or subsequent heat treatment. The main microstructural components of cast iron are: the chemical and morphological forms that carbon takes, and the continuous metallic matrix in which carbon and/or carbides are dispersed. Cast iron is the most common material for pillow block bearing seats.
Pressed steel is a type of mild steel that is pressed rather than CNC machined. Pressed steel seats are less expensive than cast or machined pillow blocks and are used in lower configuration load-bearing applications.
Stainless steel is chemically and corrosion resistant and can have relatively high pressure ratings
Sintered metal is often called powder metal bearings. They are self-lubricating, simple and low-cost. These bronze and copper alloys are porous materials that can be impregnated with oil, graphite or Teflon. They are not suitable for heavy duty applications but are useful where lubrication is not convenient.
Graphite metal alloys have bearing surfaces made from an alloy of molten graphite and metal. This material is self-lubricating.
Plastics refer to a number of organic, synthetic or processed materials, mostly high molecular weight thermoplastic or thermoset polymers, that can be made into objects, films or filaments. Common plastic materials include acetal, nylon/polyamide, and PTFE/Teflon.
Composed of various grades of polyamide, nylon is a versatile and versatile material; it is strong, durable and has good pressure ratings.
PTFE (polytetrafluoroethylene) is an insoluble compound with a high degree of chemical resistance and a low coefficient of friction. It is sometimes marketed as a proprietary class of material, such as Teflon® (a registered trademark of DuPont Dow Elastomers).
Acetal polymers are semi-crystalline. They have excellent inherent lubricity, fatigue resistance and chemical resistance. Acetal can have problems with outgassing at high temperatures and can become brittle at low temperatures. Glass filled and added lubrication grades are available, but not flame retardant grades. Brands include Celcon® (Hoechst Celanese), Delrin® (DuPont), Thermocomp® (LNP), Ultraform® (BASF) and Acetron® (DSM Polymers).
Lubrication of pillow block bearing
Like all bearings, pillow block bearings require proper lubrication to reduce wear and friction. There are three types of commercial lubricants: grease, oil, and solid film. Lubrication options include manual and self-lubricating. Manual lubrication requires a housing-mounted pump or fitting to deliver oil or grease to the friction points of the bearing. Self-lubricating bearings are made of materials such as oil-impregnated bronze or graphite/metal alloys and require no external lubrication.
How to install pillow block bearing
Pillow block bearings are typically used when the mounting shaft runs parallel to the mounting surface. The bearing seat is usually made of cast iron or cast steel, and the center line of its mounting hole is perpendicular to the mounting axis. Pillow block bearings are used to support rotating shafts, so they are made of cast steel or cast iron due to their strength and durability. Certain combinations of housing type and bearing type determine the best pillow block bearing for a given application or condition. Follow these steps to ensure minimal downtime and longer service life.
1) Check and clean the shaft
First, inspect your shaft to make sure it is clean, round, straight, free of burrs and chips, and not under or oversized to the manufacturer’s specifications. Use fine sandpaper or gloss sandpaper to remove rust from the shaft. Then apply a light coat of oil and remove any debris.
2) Position the bearing on the shaft
When installing a pillow block bearing onto a shaft, use a mallet and a block of hardwood or soft steel tubing against the inner ring if you need to knock the bearing into place. Do not knock or apply pressure to the housing or seals.
3) Gently secure the housing to the mounting structure
Position the shaft in place by gently securing the housing to the mounting structure. Bridge the housing mounting bolt slots with heavy-duty washers or heavy-duty spring lock washers. This may help prevent loosening.
4) Determine the final installation location
Before tightening the bolts, align the bearing unit with your hand or a rubber mallet to determine the final mounting position.
5) Secure the housing to the mounting structure
Once the bearings are properly aligned, bolt both units securely to the mounting structure.
6) Make sure the shaft can move axially
Make sure the shaft can move axially through the bearing hole to confirm proper alignment. If this is not possible, loosen the housing and realign the shaft.
7) Tighten the two collar fixing screws
Tighten the two collar set screws, then rotate the shaft and tighten alternately to the manufacturer’s recommended torque value. If a torque wrench is not available, use an Allen wrench to tighten the set screw until permanent twist is formed.
8) Expansion unit*
If you use an expansion unit, be sure to lock the fixed bearing first. Move the expansion bearing axially to the center of the housing. Once centered, alternately tighten the set screws on the expansion unit as you did the fixing unit.
Choose the right pillow block bearing
Choosing the right pillow block bearing for your application is critical to ensuring optimal performance and service life. The environment, load and size of the mounting shaft are major factors in selecting the appropriate pillow block bearing. In environments where contaminants are a concern, a solid bearing housing with some sealing may be the best choice. High capacity loads or harsh environments may require heavy duty pillow block bearings or even plummer housings. For light loads, a standard pillow block with a bore size matching the mounting shaft may be sufficient. Popular for its highly calculated and balanced engineering design which has been successful in the industry for quite some time. Pillow block bearings feature a straightforward design that requires little or no effort to install and provides high performance and durability. Pillow block bearings are mainly used in less industrialized environments. Please consider the following factors when selecting a pillow block bearing:
load requirements
Determine the magnitude and type of loads the bearing will encounter. This includes radial and axial loads. Make sure the selected bearings can handle the expected loads without premature failure.
Shaft speed
Consider the rotational speed of the shaft. Different bearings have specific speed limits and exceeding these limits can cause overheating and damage. Select bearings that can operate within the required speed range.
environmental conditions
Evaluate the environmental factors present in the application environment, such as temperature, humidity, and contaminants. Choose bearings with appropriate seals or guards to prevent these conditions.
Shaft size and fit
Make sure the pillow block bearing is compatible with the shaft dimensions and fit requirements. Proper shaft alignment and fit are critical to smooth bearing operation and service life.
Pillow block bearing maintenance
Proper and regular maintenance is critical to maximizing the performance and service life of your pillow block bearing. Please follow these guidelines:
Correct alignment
Ensures precise alignment between shaft and bearing housing. Misalignment can lead to increased friction, premature wear and failure.
lubricating
Lubricate bearings regularly with recommended grease or oil. Lubrication helps reduce friction and prevent excessive heat build-up.
Periodic inspection
Schedule regular inspections to check for signs of wear, damage or contamination. Promptly replace any worn or damaged parts.
Despite their reliability, pillow block bearings can still experience certain problems. Here are some common questions and troubleshooting tips:
Bearing noise
Excessive noise may indicate misalignment, insufficient lubrication, or worn components. Check bearing alignment, lubrication and condition for any abnormalities.
overheat
Overheating can be caused by overloading, insufficient lubrication or excessive friction. Make sure the bearings are properly lubricated and that the load applied is within the bearing’s capabilities.
Shaft misalignment
Misalignment can cause premature bearing failure. Regularly check the alignment of the shaft and bearing housing and make necessary adjustments.
Application of pillow block bearing
Pillow block bearings are suitable for various industrial and mechanical fields, including general machinery, motors, automobiles, metallurgy, mining and other industries. It is especially suitable for occasions with heavy load, impact, vibration load and fast rotation speed. Bearing seats are widely used in various transmission mechanisms and bearing supports, such as motors, hydraulic machinery, textile machinery, machine tools, etc. Although pillow block bearings and bearing seats are both important components of mechanical parts, their functions and positioning are slightly different. Pillow block bearing mainly carries the bearing load, orientation and stability; while the bearing seat is set on the shaft to support the bearing and position the axis center.
Aubearing is a leading manufacturer and supplier of pillow block bearings in China. With its advanced manufacturing equipment and investment in sophisticated testing instruments, Aubearing provides thousands of high-quality pillow block bearing types to 30+ countries and regions around the world. To this end, a pillow block bearing size table is summarized to provide a reference for you to choose the appropriate bearing.
Frequently Asked Questions (FAQ)
What is the service life of pillow block bearings?
Housing bearing life depends on a variety of factors, including operating conditions, maintenance practices and load capacity. With proper installation and maintenance, pillow block bearings can last for many years.
Can I replace the spherical insert bearing in the pillow block housing?
Yes, the outer spherical bearing can be replaced if it becomes worn or damaged. Make sure the replacement bearing is compatible with the housing and shaft dimensions.
How often should I lubricate pillow block bearings?
Lubrication frequency depends on operating conditions and the type of lubricant used. In general, it is recommended that pillow block bearings should be lubricated regularly according to the manufacturer’s guidelines.
Can pillow block bearing handle high-speed applications?
While chock bearings can handle moderate speeds, they may not be suitable for high-speed applications. Consider alternative bearing types designed for high-speed operation.