Introduction
In the world of machinery and mechanical engineering precision and reliability are paramount. One crucial component that plays a significant role in ensuring the smooth operation and longevity of rotating machinery is the cylindrical roller bearing. Specifically, in this blog post, we’ll delve into the details of Single-Row Cylindrical Roller Bearings, exploring their design, advantages, and applications.
Understand Cylindrical Roller Bearings
The Single-row cylindrical Roller Bearings are a type of rolling element bearing designed to provide high radial load capacity. These bearings consist of cylindrical rollers held in place by a cage which guides the rollers to ensure they move in a straight line. The outer and inner rings of the bearing can be separated allowing for easy installation and maintenance.
The rollers of single-row cylindrical roller bearings with cages are guided between integral flanges on one of the bearings. The bearing ring with integral flanges and the rollers and cage assembly can be withdrawn from the other ring. This facilitates mounting and dismounting particularly where both rings have to have interference fits because of the load conditions.
Single-row cylindrical roller bearings have high radial load carrying capacity and also high-speed capability. they have produced different designs which are different in the configuration of the flanges.
The cylindrical roller bearing of the NU type has two integral flanges on the outer ring and the inner ring without flanges, whereas the N-type has two integral flanges on the inner ring and an outer ring without flanges. Axial displacement of the shaft with respect to the housing is permitted in both directions within certain limits, i.e. changes in length because of thermal expansion can be accommodated and the bearings are therefore suitable as non-locating bearings.
Cylindrical roller bearings of the NJ type have two integral flanges on the outer ring and one integral flange on the inner ring so that axial location can be provided for the shaft in one direction.
Cylindrical roller bearing type NUP have two integral flange on the outer ring and the inner ring has one intergral and one loose flange, enabling the bearing to locate a shaft axially in both direction.
NJ-type cylindrical bearing when used to locate the shaft axially in both directions whilst the combination of an NU bearing with the HJ angle ring will locate the shaft axially in one direction. It is not advisable to fit angle rings at both sides of an NU-type bearing as can lead to axial compression of the rollers.
The cylindrical roller bearing of the EC design has an appreciably higher load-carrying capacity for the same boundary dimensions than the earlier design because of improvement to the internal geometry. The new design of the guide surfaces of the flanges and of the ends of the roller has also meant that the EC bearing has a high axial load-carrying capacity. The favorable contact condition also contributes to better lubrication of the roller’s end/flange contact.
These characteristics make cylindrical roller bearings of the EC design particularly useful. They represent the standard design for the most popular size of bearing series like 10, 2, 22, 3, and 23.
Misalignment Of Cylindrical Roller Bearings
Misalignment in cylindrical roller bearings can lead to various troubles, which include increased friction, untimely wear, and reduced common overall performance. It’s vital to address misalignment directly to ensure the right functioning and durability of the bearings. Here are some not-unusual causes and potential answers for misalignment in cylindrical roller bearings:
The ability of single-row cylindrical roller bearing to accommodate angular misalignment of the inner ring with respect to the outer ring, and thus to compensate for errors of alignment, is limited to a few minutes of arc. For cylindrical roller bearings which have a logarithmic contact profile the actual values are:
- 4 minutes of arc for bearing of the narrow series like 10, 2, 3, and 4.
- 3 minutes of arc for bearing of the wide series like 22 and 23.
Larger misalignments are possible, depending on the load and requisite life. in such cases, it is recommended that the batter-bearing application service.
Causes of Misalignment
1-Improper Installation:
Solution: Make sure the bearings are installed according to the manufacturer’s instructions. Follow recommended procedures for installing, dismounting, and assembling bearings.
2-Shaft or Housing Deflection
Solution: Check for shaft or housing deflection and correct any misalignment problems. If necessary, reinforce shaft or housing structure to prevent sagging.
3-Loose Fits:
Solution: Check that fits between bearing shaft/housing are within specified tolerances. Tighten any loose fittings and use the correct locking mechanism.
4-Thermal Expansion
Solution: Consider the thermal expansion of the shaft and housing during operation. Provide adequate clearance to accommodate temperature changes or use an expansion joint.
5-Axial Load
Solution: Excessive axial loading can cause misalignment. Check the axial load on the bearing and make sure it falls within the recommended limits. Use proper thrust bearings if necessary.
Solutions for Misalignment
1-Self-aligning Bearings
Consider using self-aligning cylindrical roller bearings. These bearings have a degree of inaccuracy.
2-Alignment Tools
Use precision fitting tools during installation to ensure proper shaft and housing alignment. Laser alignment tools are commonly used for this purpose.
3-Routine Maintenance
Use a routine maintenance schedule to check the condition of the bearing. Check for signs of misalignment and address any problems immediately.
4-Check out the manufacturer’s instructions
Always refer to manufacturer’s guidelines and specifications for proper installation, maintenance and alignment procedures.
5-Administrative Support
If misalignment issues persist or are difficult to deal with, consider seeking the help of a professional mechanic or bearing specialist.
Axial Internal Clearance Of Cylindrical Roller Bearings
Axial internal clearance, in roller bearings can be compared to a designated area or allowance near the bearing axis, where there is some flexibility for movement without causing any issues. This allowance plays a role in accommodating factors such as temperature fluctuations and slight variations in the design of bearing components ensuring the performance of the bearing.
In terms, it’s akin to having a position within a cylindrical roller bearing that allows for some movement, around its center.
Why it matters: This space is necessary for a trouble-free trigger. It helps deal with things like temperature fluctuations and minor differences in part design.
Troubleshooting: Having this position prevents the bearing from overheating, reduces friction, and keeps everything stable, especially during operation
Why they differ: Different bearings operate under different conditions, so the space needed to deal with changes in temperature and other factors varies.
Cylindrical roller bearing of the NUP type and NJ type with HJ angle ring, which can serve to locate the shaft in both directions, internal clearance according to the bearing type. The exceptions to this rule are bearing for traction motors made to the VA301 specifications which have an axial internal clearance corresponding to DIN 43283.
Internal clearance should be considered as guideline values, because of roller tilting during measurement of the axial internal clearance increases in the clearance are possible. These correspond for bearing series 10, 2, 3, and 4 to approximately half the radial internal clearance and for bearing of series 22 and 23 to approximately 2/3 of the radial internal clearance.
Cages Of Cylindrical Roller Bearings
Cylindrical Roller Bearings Cages can be made from different materials, like steel, brass, or plastic (polyamide). The choice depends on things like how much load and speed the bearing will handle.
1-Steel Cages: Strong and good for high temperatures. Used in heavy-duty and high-speed situations.
2-Brass Cages: Wear-resistant and used where there might not be much lubrication. Good for medium to high speeds.
3-Polyamide Cages: Lightweight, corrosion-resistant, and good for lower loads and speeds. Used in things like electric motors.
Single row cylindrical roller bearing fitted with glass fiber reinfored polyamide 6,6 cages can be used at operating temperatures up to +120 C. For bearing arrangement which have to operate at high temperature continuously or under arduous condition.
These bearing can be supplied with a pressed steel cages instead of the polyamide cage. Bearing which incorporate a pressed steel cage as stand can also manufacture with a machined brass cage.
Minimum Load
The satisfactory operation of all ball and roller bearing they must always be subjected to a given minimum load. This is also true of cylindrical roller bearing, particularly if they run at speeds where the inertia force of the rollers and cage and the friction of the lubricant can have a detrimental influence on the rolling conditions in the bearing and may cause damaging sliding movements to occur between the rollers and the raceways.
The requisite minimum radial load to be applied in such cases can be estimated from
Frm = Kr( 6+4n/nr) ( dm/100)2
Where Frm = minimum radial load, N
Kr = Minimum load factor =100 for bearing of series 10 =150 for bearing of series 2, 3 and 4 = 200 for bearing of series 22 = 250 for bearing of series 23
n= operating speed r/min nr= speed rating for oil lubrication r/min dm= mean diameter of bearing = 0,5 (d+D), mm
The weight of the components supported by the bearing together with the external force, often exceeds the requisite minimum load. If this is not the case, the bearing must be subjected to an additional radial load. e.g by increasing belt tension, increasing idling torque, or by other means.
Equivalent Dynamic Bearing Load
When cylindrical roller bearings are used as non-location bearings and are only subjected to radial load, the equivalent dynamic bearing load P=Fr
If cylindrical roller bearings with flanges on inner and outer rings are used to axially locate the shaft in one or both directions, as is frequently to case, the equivalent dynamic bearing load should be calculated using
P=Fr When Fa/Fr < e p=0,92 Fr + YFa When Fa/Fe > e
Where e=calculation factor =0,2 for bearing of series 10, 2, 3 and 4 =0, 3 for bearing of series 22 and 23
Y=axial load factor =0, 6 for bearing of series 10, 2, 3 and 4 =0,4 for bearing of series 22 and 23
Since axially loaded cylindrical roller bearings will only operate satisfactorily when they are subjected to a simultaneously acting radial load, the ratio Fa/Fr should not exceed 0,5 for EC design bearing and 0,4 for the other bearings.
Dynamic axial load carrying capacity
Cylindrical roller bearings with flanges on both inner and outer rings can support axial loads in addition to radial loads. Their axial load carrying capacity is not primarily determined by the fatigue strength of the material sliding surfaces at the roller end and flange contact and is thus mainly.
Governed by the lubrication, operating temperature, and heat dissipation from the bearing. Assuming the condition cited below, the permissible axial load can be calculated with sufficient accuracy from
Fap= K1 Co 104/ n(d+D)-K2 Fr
Where Fap= maximum permissible axial load, N Co= basic static load rating, N Fr= actual radial bearing load, N n= operating speed, r/min d= bearing bore diameter, mm
The above equation is based on conditions which are considered typical for normal bearing operation:
- A difference of 60 degree between the bearing operating temperature and the ambient temperature
- A specific heat loss from the bearing of 0,5 mW/MM2 degrees
- A viscosity ratio K=2
The viscosity ratio k is the ratio of the actual viscosity v at the operating temperature to the requisite viscosity V1 for adequate lubrication at that temperature. For grease lubrication, the base oil viscosity of the grease should be used for v.
If the k is less than 2 friction will increase and there will be wear. These effects can be reduced at low speeds, for example, by using oil with EP additives.
The values of the permissible axial load Fap obtained from the equation are valid for a continuous action constant axial load. Where axial load acts only for short periods, the values may be multiplied by or for shock loads by 3.
The constantly acting axial load Fa(in newtons) applied to the bearing should never exceed the numerical value of 1,2 D2 (D=bearing outside diameter in mm) and occasional shock loads should never be greater than the numerical value of 3 D2.
To obtain an even flange load and a sufficient running accuracy of the shaft, the axial runout of the abutment surfaces on the associated components of cylindrical rollers bearing subjected to heavy axial loads.
Cylindrical Roller Bearing Size Chart
Cylindrical roller bearings come in a different variety of sizes and specifications and typical sizing specifications can vary depending on the manufacturer and bearing type A cylindrical roller is basically identified by their bore diameter outer diameter and width bearings. The magnitude chart usually incorporates these parameters.
Here is a simple example of what a cylindrical roller bearing size chart looks like.
| Bearing Series | Bore Diameter (d) | Outer Diameter (D) | Width (B) |
| NU 200 Series | 10 mm | 30 mm | 9 mm |
| NU 300 Series | 20 mm | 52 mm | 15 mm |
| N 200 Series | 15 mm | 35 mm | 11 mm |
| N 300 Series | 25 mm | 62 mm | 17 mm |
Cylindrical Roller Bearing Application
Cylindrical roller bearings are widely used in many industries due to their capability to tolerate great radial loads and moderate thrust loads. Here are some applications of cylindrical roller bearings:
1-Aircraft Landing Gear
Aircraft Landing Gear: Cylindrical roller bearings find use in aircraft landing gear assemblies where they provide necessary support for the radial loads that occur at the time of taking off, landing and taxiing.
2-Printing and Papermaking
Paper Machine Rolls: Cylindrical roller bearings are used in paper machines to support rolls that handle paper at various stages of production.
3-Wind Turbines
Main Shaft Bearings: In wind turbine generators, the main shaft uses cylindrical roller bearings that take care of both the radial and axial loads generated by the blades as they rotate.
4-Automotive Industry
Wheel Bearings: The cylindrical roller bearings are used in the wheel hubs of cars and trucks to take care of the vehicle’s mass and loads acting on it as it moves.
5-Machine Tools
Spindle Bearings: In machines such as lathes and mills, cylindrical roller bearings are used in the spinning part of the machine to carry such weight and keep it spinning accurately.
6-Electric Motors
Motor Bearings: Cylindrical roller bearings are used in electric motors to support their rotating parts while handling the weight during operation of the motor.
7-Gearboxes and Transmissions
Gearbox Bearings: Geared systems which use cylindrical rollers extensively for supporting loads brought about by gears that turn at high speeds.
8-Steel Industry
Rolling Mill Bearings: Shape mill rolls bring about heavy weights as well as high speeds hence cylindrical roller bearings being used for support.
9-Mining and Construction Equipment
Crushers and Screens: For example, crushers and screens employ cylindrical roller bearings to hold up under crushing forces involved in crushing, screening, etc.
10-Railway Industry
Axle box Bearings: Cylindrical roller bearings are extensively employed in various sections of railway trains carriage that supports wheel set, ensuring stability during motion and bearing its own weight.
Advantages Of Cylindrical Roller Bearings
Cylindrical roller bearings particularly single-row cylindrical roller bearing offer the some advantages in different applications. Here we are some of the key advantages:
1-High Radial Load Capacity 2-Space Efficiency 3-High Speed Capability 4-Ease of Installation and Maintenance 5-Versatility in Design 6-Alignment Compensation 7-Durable and Long-Lasting 8-Customization Options 9-Wide Range of Sizes 10-Cost-Effective
FAQs
1-What is Cylindrical Roller Bearing?
Answer: They provided high load capacity under primarily radial loads. Low friction between the rollers and ring ribs makes these bearings acceptable for high-speed rotation.
2-Why do we use cylindrical bearings?
Answer: Cylindrical bearings effectively withstand damage from fatigue, shock, and edge loads, and they demonstrate superior tolerance to misalignment compared to rolling element bearings. Basically, customers will experience savings from lower maintenance costs and extended equipment life
3-How many types of roller bearings are there?
Answer: Rollers are available in four types: cylindrical, needle, tapered, and spherical. which geometrically contact with the raceway surfaces of the inner and outer rings at “points”, rollers establish a “line” contact on the contact surface.
4-Where are cylindrical roller bearings used?
Answer: The cylindrical roller bearings are utilized in high-speed systems & can be deployed for high-performing systems like agricultural machinery, wind turbines, mining machines, etc.
5-What is the bearing in the cylinder?
Answer: A bearing is a component utilized to reduce friction and to maintain clearance between stationary & rotating components of the engine or machines. Bearings, or bearing surfaces, are located on the crankshaft, connecting rod, and camshafts, and also in the cylinder block.
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