A Comprehensive Guide to Bearings Solutions

What is a bearing?

Bearing (Japanese name ‘jikuuke’) is a component that fixes and reduces the load friction coefficient during mechanical transmission. When other parts have relative motion with each other on the shaft, it is used to reduce the friction coefficient in the power transmission process and keep the shaft’s center position fixed.

Figure 1 shows how the “shaft” rotates, causing the rolling elements (“balls” or “rollers”) inside the bearing to roll.Bearings reduce friction by means of this rolling motion.

Figure.1 The structures of a rolling bearing and a plain bearing

The “rolling bearing”, with its rolling motion, reduces friction more than the “plain bearing” with its sliding motion, allowing for a greater decrease in the amount of energy consumption during rotation.

The role of bearings

Bearing is an important part of modern mechanical equipment. Its main function is to support the mechanical rotating body to reduce the mechanical load friction coefficient of the equipment during the transmission process.

In order to make the machine run smoothly, what role does the bearing play?
It has two functions:

1. Reduce friction and make the rotation smoother

Friction must occur between the rotating ‘axis’ and the rotating support part. The bearing is used between the rotating ‘ shaft ‘ and the rotating support part.
Bearings can reduce friction, make rotation smoother, and reduce energy consumption. This is the role of bearings.

1. Protect the rotation support section so that the ‘shaft’ of rotation is kept in the correct position.

There will be much force between the rotating ‘axis’ and the rotating support part. The bearing can prevent the rotating support part from being damaged by this force so that the rotating ‘ shaft ‘ is kept in the correct position.
Because of these effects of bearings, we can use the machine repeatedly for a long time.

The working principle of bearing

The working principle of rolling bearing is to replace sliding friction with rolling friction. Generally, it comprises two rings, a group of rolling elements, and a cage, a highly versatile, standardized, and serialized mechanical basic part. Due to the different working conditions of various machines, different requirements are put forward for rolling bearings in terms of load capacity, structure, and performance. For this reason, rolling bearings need to have a variety of structures. However, the most basic structure comprises an inner ring, an outer ring, a rolling element, and a cage – usually called the four major pieces.
The early form of linear motion bearing was to place a row of wooden poles under a row of skid plates. Modern linear motion bearings use the same working principle, but sometimes balls are used instead of rollers. The simplest rotating bearing is the sleeve bearing, just a bushing sandwiched between the wheel and the axle.

This design was then replaced by rolling bearings, which replaced the original bushing with several cylindrical rollers, each like a separate wheel. Due to the difference in manufacturing accuracy and material uniformity, even if the same material and the same size of the same batch of bearings are used under the same working conditions, the length of life is different.

The structure of bearings

Modern bearings come in various types, but their basic structure is almost identical to that created 500 years ago by Leonardo da Vinci.

1. Bearing rings (races): The ring-shaped components.
2. Rolling elements: The components that roll between the bearing rings (races); rolling elements can be either “balls” or “rollers”.
3. Cage: The component that maintains a fixed gap so the rolling elements don’t come into contact with each other.

Bearing rings
Figure 2 shows two “radial bearings” supporting a force applied perpendicularly to the shaft.
“Ball bearings” use balls as their rolling elements, while “roller bearings” use “rollers” as their rolling elements.

Figure.2 The structures of radial bearings (JTEKT Corporation)
Bearing rings are used for these radial bearings.
The bearing ring on the inside, into which the shaft is inserted, is called the inner ring.
The one on the outside is called the outer ring and is inserted into the housing* (as seen in Figure 3).
Housing
“Housing” refers to the components that come in contact with the outer ring when the bearing is inserted.

Figure.3 Housing
Reference: Please click here for more detailed information on the design of the shaft and housing
Races
Figure 4 shows two “thrust bearings”, which support a force applied in the same direction as the shaft.
Races are used for these thrust bearings.
The race on the side into which the shaft is inserted is called the shaft race.
The race inserted into the housing is called the housing race.

Figure.4 The structures of thrust bearings
The surfaces of bearing rings (races) on which the rolling elements roll are made extremely smooth to allow for smooth bearing rotation.
Rolling elements
Table.1 Shows the “balls” and “rollers” used as rolling elements.

Table 1: The different shapes of rolling elements

	Ball	Ball bearing
	Cylindrical roller	Roller bearing
	Needle roller
	Tapered roller (tapered trapezoid)
	Convex roller (barrel-shaped)

There are a variety of different rolling elements designed to suit the specific conditions of the bearings, such as the strength of the supporting force or the speed of the rotation.

Types of bearings

• Bearing according to the direction of load bearing or nominal contact angle is divided into centripetal bearings and thrust bearings.
• According to the type of rolling body is divided into: ball bearings and roller bearings.
• According to whether it can be centering, it is divided into: centering bearings and non-aligning bearings (rigid bearings).
• The number of columns of rolling elements is divided into: single-row bearings, double-row bearings, and multi-row bearings.
• The parts can be separated or divided into separable or non-separable bearings.

In addition, they are also according to the structure, shape, and size of the classification.
1. Angular contact ball bearings

Between the collar and ball contact angle, the standard contact angle of 15 °, 30 ° and 40 °, the larger the contact angle axial load capacity is the larger, the smaller the contact angle is more conducive to high-speed rotation, single-row bearings can withstand radial loads and unidirectional axial loads. The structure for the back of the combination of two single-row angular contact ball bearings shares the inner and outer rings. It can withstand radial and bi-directional axial loads.

Angular contact ball bearing main use:

• Single row: machine tool spindle, high-frequency motor, combustion turbine, centrifugal separator, small car front wheel, differential pinion shaft.
• Double row: oil pump, Roots blower, air compressor, transmission, fuel injection pump, printing machinery.

2. Spherical ball bearings

Double rows of steel balls, the outer ring raceway is inner spherical type, so it can automatically adjust the axis incorrectly caused by the deflection or different centering of the shaft or shell, tapered hole bearings can be easily mounted on the shaft through the use of fasteners, and it mainly bears radial loads.

Main applications: woodworking machinery, textile machinery drive shaft, vertical with seat spherical bearings.
3. Spherical roller bearings

This kind of bearing in the spherical raceway outer ring and double raceway inner ring is equipped with spherical roller, according to the internal structure of different, divided into R, RH, RHA and SR four types, because the outer ring raceway arc center and bearing center, has the performance of self-aligning so that it can be automatically adjusted due to the axis or shell of the deflection or different heart caused by the axis of the incorrect, can withstand radial loads and bi-directional axial loads.

Spherical roller bearings main use:
Paper-making machinery, deceleration device, railroad vehicle axle, rolling mill gear box seat, rolling mill roller road sub, crusher, vibrating screen, printing machinery, woodworking machinery, all kinds of industrial speed reducer, vertical with seat self-aligning bearings.
4. Thrust spherical roller bearings

Spherical roller tilt arrangement in this type of bearings, due to the spherical seat ring raceway surface, has a centering performance, allowing the shaft to have several tilts. Axial load capacity is very large in the bear axial load and can also bear several radial loads; oil lubrication is generally used.

Thrust spherical roller bearings main use:
Hydroelectric generators, vertical motors, propeller shafts for ships, speed reducers for rolling screws in steel mills, tower cranes, coal mills, extruders, molding machines.
5. Tapered roller bearings

This kind of bearing is equipped with a circular table shape roller, roller by the inner circle of the big edge guide. The design makes the inner ring raceway surface, outer ring raceway surface, and roller rolling surface of the conical surface of the apex of the intersection of the bearing center line on a point. Single-row bearings can withstand radial and unidirectional axial loads, and double-row bearings can withstand radial and bi-directional axial loads, suitable for bearing heavy and shock loads.

Tapered roller bearings main use:
Automobile: front wheel, rear wheel, transmission, differential pinion shaft. Machine tool spindle, construction machinery, large agricultural machinery, railroad vehicle gear reduction device, rolling mill roll neck and reduction device.
6. Deep groove ball bearings

In the structure of deep groove ball bearings, each ring has a cross-section of about one-third of the equatorial circumference of the continuous groove-type raceway. Deep groove ball bearings are mainly used to bear radial loads but can also bear certain axial loads.

When the radial clearance of the bearing increases, it has the nature of an angular contact ball bearing and can withstand alternating axial loads in both directions. Compared with other types of bearings of the same size, this type of bearing has a small friction coefficient, high limiting speed and high precision, and it is the preferred type of bearing when the user selects the type.
Deep groove ball bearings’ main use:
Automobiles, tractors, machine tools, motors, water pumps, agricultural machinery, textile machinery, etc.
7. Thrust ball bearings

The gasket-shaped raceway ring has with raceway and ball and keeps the frame assembly composition, and shaft with the raceway ring is called an axis ring, and the shell with the raceway ring is called a seat ring.

Bidirectional bearings will be the middle ring secret shaft with one-way bearings that can withstand one-way axial load; two-way bearings can withstand two-way axial load (both cannot withstand radial load).

Thrust ball bearings are mainly used: automobile steering pin and machine tool spindle.
8. Thrust roller bearings

Thrust roller bearings are used to withstand axial load-based shaft, the warp direction joint load, but the warp direction load shall not exceed 55% of the axial load. Compared with other thrust roller bearings, this bearing friction factor is low, high speed, and can adjust the center. 29000 type bearing roller for asymmetric spherical roller can reduce the stick and raceway in the work of the relative sliding, and the roller long, diameter, roller number of load capacity, usually use oil lubrication, the individual low-speed situation can be lubricated with grease.

Thrust roller bearings are mainly used: hydroelectric generator and crane hook.
9. Cylindrical roller bearings

Cylindrical roller bearings roller is usually guided by a bearing collar of two retaining edges, keeping the frame roller and guiding the collar to form a combination of parts, which can be separated from another bearing collar belonging to the separable bearings.

This kind of bearing installation disassembly is relatively convenient, especially when the inner and outer ring and shaft shell requirements interfere with fit more show the advantages. These bearings are generally only used to bear radial load; only inside and outside the ring with the edge of the single-row bearings can withstand a small fixed axial load or a larger intermittent axial load.
Cylindrical roller bearings are mainly used for large motors, machine tool spindles, axle shafts, diesel engine crankshafts, and automobiles, to keep in mind the gearbox.
10. Four-point contact ball bearings

Can withstand radial load and two-way axial load, a single bearing can replace the front combination or back combination of angular contact ball bearings, suitable for bearing pure axial load or axial load composition of larger synthetic load; this kind of bearing to withstand any direction of axial load can be formed in one of the contact angles, so the collar and the ball are always in any contact line on the two sides of the three cutter point contact.

Four-point contact ball bearing main use: aircraft jet engine, combustion turbine.
11. Thrust cylindrical roller bearings

By the gasket-shaped raceway ring (shaft circle, seat ring) and cylindrical roller and keep frame assembly.

Cylindrical roller using convex surface processing, so the pressure distribution between the roller and raceway surface is uniform, can withstand unidirectional axial load, axial load capacity, and axial rigidity is also strong.

Thrust cylindrical roller bearings are mainly used in oil drilling rigs, iron and steel-making machinery.
12. Thrust needle roller bearings

Separate-type bearings comprise raceway rings, needle rollers, and cage assemblies, which can be combined arbitrarily with stamping processed thin raceway rings or cutting processed thick raceway rings. Non-separate bearings by the precision stamping processing of the raceway ring and needle roller and cage assembly constitute the whole type of bearing that can withstand the unidirectional axial load; this type of bearing occupies a small space, is conducive to the compact design of the machinery, most of the needle roller and cage assembly, and the shaft and the shell of the mounting surface as the use of the raceway surface.

Thrust needle roller bearings’ main use: automobile, cultivator, machine tools, and other variable speed device.
13. Thrust tapered roller bearings

This kind of bearing is equipped with a circular table shape roller (big end for the sphere), roller by the raceway circle (axle circle, seat circle) retaining edge accurate guide; design makes the axle circle and seat circle raceway surface and the roller rolling surface of the conical surface of the apex of the intersection of the bearing center line on a point, one-way bearing can withstand the unidirectional axial load, bi-directional bearings can withstand the bi-directional axial load.

Thrust tapered roller bearings main use:

• One-way: crane hook, oil drilling rig rotary ring.
• Bidirectional: steel mill roll neck.

14. Housed external spherical ball bearings
The outer spherical ball bearing with seat comprises an outer spherical ball bearing with seal on both sides and casting (or steel plate stamping) bearing seat. The internal structure of the outer spherical ball bearings and deep groove ball bearings, but the inner ring of such bearings is wider than the outer ring, the outer ring has a truncated spherical surface, and the concave sphere of the bearing housing can be matched with automatic self-aligning.

Materials of bearings

The materials of bearings include metallic and non-metallic materials. Metallic materials include steel, copper, aluminum, etc., of which the most commonly used is steel. Steel has high wear resistance and strength and is suitable for making bearings with high loads and high speeds. Non-metallic materials include plastics, ceramics, fibers, etc. They are lightweight, corrosion-resistant, insulating, etc., and suitable for making bearings with low loads and speeds.
Bearings can be divided into small, medium, large, and large categories. The inner ring, outer ring, and rollers of bearings are generally made of high-carbon steel GCr15, which corresponds to the German grade 100Cr6, and GCr15SiMn, which corresponds to the German grade 100CrMn6; these are commonly known as bearing steels, and they are important basic steel used in the manufacture of equipment bearings, with properties such as long service life, high precision, high stiffness, and high wear resistance.

Common Material Types of Bearing Steel

High carbon chromium bearing steel	GCr15 GCr15SiMn	GCr18Mo GCr4	GCr15SiMo
Medium carbon chromium bearing steel	G8Cr15
Carburized bearing steel	G20CrNi2MOA	G20Cr2Ni4A	G20CrNiMoA
Stainless bearing steel	9Cr18	9Cr18Mo
High temperature bearing steel	Cr4Mo4V 2W10Cr3NiV	H10Cr4Mo4Ni4V W18Cr4V	W9Cr4V2Mo

Chromium Bearing Steel

There are special requirements for making bearings. GCr9, GCr15 or GCr15SiMn are used for small-sized bearings, GCr15SiMn for medium-sized bearings, GCr15SiMn for large-sized bearings, and carburized bearing steels are considered for extra-large bearings.
Carburized Bearing Steel
In metallurgy, steel rolling machinery and equipment or mining and mineral processing and other machinery need to face a greater impact on the working conditions of the application of bearings, generally use carburized bearing steel manufacturing, small and medium-sized can choose 20Cr carburized steel, large and very large general selection of 20Cr2Ni4A, 20Cr2Mn2MoA and so on.
Stainless bearing steel
Stainless bearing steel: such as sulfuric acid, hydrochloric acid, fertilizers and other corrosive working environments with the application of bearings can be selected stainless bearing steel manufacturing; the material is usually such as 9Cr18 steel and other high-carbon, high-chromium stainless steel.
High-temperature bearing steel
Usually used in the high-temperature working environment of the bearing, the type of steel usually includes high-speed steel 18-4-1 and 6-5-4-2 and Cr4Mo4V and Cr15Mo4, and so on.

Bearing cage, also known as bearing retainer, the material is common: mild steel, stainless steel, plastic wood, plastic nylon, brass, bronze, aluminum alloy, and so on.

Application of bearings

Bearings are machine elements that allow parts to move relative to one another, typically rotational or linear. They play a vital role in reducing friction between moving parts, which not only helps in saving energy but also extends the lifespan of the parts involved. There are various types of bearings, including ball, roller, thrust, and many others, each designed for specific applications. Here are some common applications of bearings:

• Automotive Applications: Bearings are used extensively in cars, trucks, and motorcycles. They can be found in wheels, transmissions, axles, steering systems, and engine components.
• Industrial Machines: Almost every rotating machinery, from conveyors to large turbines, will contain bearings. They ensure the smooth operation of these machines.
• Aerospace: Aircraft have many rotating parts, from engines to landing gear. Bearings help ensure these parts operate efficiently.
• Electrical Motors: Electric motors use bearings at both ends of the shaft to allow the rotor to spin freely inside the stator.
• Household Appliances: Devices like washing machines, dryers, and fans use bearings to ensure their moving parts function smoothly.
• Bicycles: Ball bearings are used in the wheel hubs, bottom brackets, and sometimes in the headset and pedals of bicycles.
• Wind Turbines: These use large bearings to support the rotating blades and the generator shaft.
• Railways: Bearings are used in the axles of railway cars to allow for smooth and efficient movement.
• Computers and Precision Instruments: High-precision ball bearings are used in hard drives. Moreover, precision instruments in laboratories also use specialized bearings to ensure accurate movements.
• Skateboards and Roller Skates: They roll smoothly with bearings on their wheels.
• Marine Applications: Ships and submarines use bearings in their propeller shafts, turbines, and other equipment.
• Medical Devices: Some medical imaging equipment and precision medical tools use bearings for accurate movement.
• Agriculture: Tractors and other agricultural machinery often contain several types of bearings, ensuring their various moving parts function efficiently.
• Construction: Construction equipment, such as bulldozers, excavators, and cranes, use bearings in their joints and moving parts.

In addition to these applications, bearings are used in many other scenarios, from simple tools to complex machinery. They are integral to the function of numerous devices and systems and are continually innovated to meet new technologies’ demands.

How are bearings mounted? Bearing mounting procedure

When using precision rolling bearings, it is very important to mount them to obtain the highest rotational speed and low-temperature rise.

The mounting of bearings includes cleaning, drying, and test run (grease encapsulation), etc., and should be performed in accordance with the precautions.
In addition, since grease is encapsulated inside the sealed bearings, they should not be cleaned or dried and should be assembled after wiping off the external antirust oil with a clean rag.
Step 1: Clean the bearings to remove the antirust oil.
After soaking and hand-turning with a high-volume solvent such as refined kerosene and naphthol to clean it, remove refined kerosene, etc., with gasoline and ethanol. When blowing off cleaning oil with an air gun, pay attention to the cleanliness of the air. When oil-air lubrication is used, it can be used directly, but it is recommended that it be used after being coated or soaked in lubricant or low-viscosity oil after cleaning.
Step 2: Dry the bearings without moisture residue.
When using grease lubrication, it is necessary to dry the bearings sufficiently to prevent the grease from flowing out. In addition, they should be sealed with grease immediately after drying. Drying can be carried out with warm air (attention should be paid to the cleanliness of the air) or in a constant temperature bath.
Step 3: Encapsulate the grease.
After encapsulation, turn the rolling part by hand to fully coat the grease.
Ball bearings can be used syringe, vinyl plastic bag aligned with the inner ring rolling surface, between the ball and ball equal amount of encapsulated grease. When there is a raceway ring-guided cage, it is recommended to use a spatula and other small tools to apply it to the cage-guiding surface. If it is not possible to encapsulate the rolling surface of the inner ring due to the narrow space of the inner ring, encapsulate the rolling surface of the outer ring. In this case, every effort should be made to rotate by hand to make the grease penetrate into the inner ring.
When applying grease to the outer diameter surface (inner diameter surface) of the rollers of roller bearings, rotate the rollers with your fingertips to make the grease penetrate into the inner ring (outer ring).
Step 4: Test run.

• 1. Oil-air and oil-mist lubrication. In oil lubrication, the bearing temperature reaches a steady state quickly before it reaches the peak value. Therefore, the trial run is relatively simple. Keeping the speed at 2000-3000 rpm for about 30 minutes and gradually increasing the working speed is recommended. However, dmn (rolling body center diameter * speed) is more than 1 million times the range. To ensure safety, there should be 1,000-2,000 revolutions per minute as a unit to speed up.
• 2. Grease lubrication. In grease lubrication, the test run is very important to stabilize the temperature rise. When the test run is carried out after the speed is increased, the temperature rise is shown to be faster, and after it reaches the peak, the temperature will stabilize slowly. It will take some time to stabilize.
• 3. Ball bearings. It is recommended that the unit of 1000-2000 revolutions per minute and then speed up after the temperature is stabilized. dmn (rolling body center diameter * speed) more than 400,000 times the range of speed, to be safe, should be 500-1000 revolutions per minute unit of speed.
• 4. Roller bearings. Compared with ball bearings, roller bearings have a longer time to reach peak and stabilization temperatures during trial operation. In addition, since the temperature change cannot be stabilized due to the temperature rise caused by the re-inclusion of grease, they should be operated for a longer period at the maximum speed. It is recommended to run the bearing at 500-1000 revolutions per minute and then increase the speed after the temperature has stabilized. dmn (diameter of rolling element center * rotational speed) exceeds 300,000 cycles, so 300 revolutions should increase the speed to be safe.

Step 5: Assemble the bearings.
When assembling the bearings on the spindle, the shaft and the inner ring of the bearings for the interference fit (tight fit) assembly method are usually used in hydraulic presses and inserted through the hot installation of two methods.
No matter which method is used, it is necessary to minimize the impact of assembly and maintain the accuracy of the bearing.

1. Pressing in with a hydraulic press
When pressing in bearings by means of a manual press, etc., it is first necessary to calculate the press-in force based on the interference between the shaft and the inner ring (a hydraulic press with a working pressure greater than the required pressure must be used). Then, when pressing in the inner ring, the inner ring press-in tool should be used to actually press it into the shoulder of the shaft (do not apply force to the outer ring). After pressing in, measure the accuracy of each part of the bearing to confirm that it is actually mounted on the shaft. In addition, when using multi-row bearings, the runout should be measured after assembly to correct the axial deviation between the outer rings.
2. Insertion by hot mounting
Make full use of the reason for thermal expansion and contraction, and insert the bearing after heat expansion; it generally is heated to the degree of 30 degrees. You need to pay attention to: the use of resin material as the angular contact ball bearing cage; don’t heat to too high a temperature; the highest shall be at most 80 degrees. Because of cooling, the inner ring shrinks toward the shaft, and a clearance between the bearing and the shaft shoulder will be generated, so after fitting, reduce to room temperature, and then press it with a hydraulic press or the like. Also, check the perpendicularity after cooling. When heating with a bearing heater, be careful of excessive temperature rise, and use equipment with a demagnetizing device that can remove residual magnetism.
Step 6: Fix the inner ring.
When mounting and fixing the spindle bearing, the inner ring side is usually tightened with a trapezoidal socket or precision bearing nut, and the front cover is tightened with a bolt on the outer ring side. The following points should be noted when using a trapezoidal socket or precision bearing nut to fasten the inner ring.
1. Fastening with a ladder sleeve
A trapezoidal sleeve is an easier fixing method by inserting the sleeve, which expands due to oil pressure, onto the shaft, applying the required press-in force (tightening force), removing the oil pressure, and applying a lyrical tightening force to the bearing while fixing the sleeve on the shaft.
However, since the fixing of the sleeve is realized only by interference with the shaft, it may loosen when the shaft is bent and subjected to moment load.
2. Tightening with precision bearing nut
Tightening with a precision bearing nut (precision lock nut) will give the appropriate tightening force in accordance with the tightening torque management regulations for precision lock nuts.
In addition, when the bearing is fixed with a precision bearing nut, the nut is tilted due to the clearance of the thread, and fine adjustment may be required to realize the rotational accuracy of the shaft.
3. Relationship between tightening torque and tightening force of the precision bearing nut
Since the threaded surface of the precision bearing nut, the threaded surface of the shaft, and the seating surface of the precision bearing nut are sliding surfaces, the relationship between the torque and the tightening force changes according to the coefficient of friction at the time of tightening. They should be made to fully break in.
In addition, it is important to calibrate the relationship between the tightening torque and the tightening force by using a force-measuring washer or the like in advance.
Up to this point, the installation of bearings has been basically completed. Still, due to the installation process, it may lead to such as gasket deformation, the front cover crimp producing margins, clearance being too large or too small and other issues in the next chapter, I will bring you the solution to this type of installation problems, to ensure that the installation of the bearings can maintain the best operating conditions, long operation without failure.

Common problems and solutions in the use of bearings

Strong metal sound

• 1. Abnormal load: Select the appropriate assembly clearance and preload force.
• 2. Poor assembly: Improve shaft machining accuracy and installation methods.
• 3. Insufficient lubricant: Supplement or use suitable lubricant.

Regular sound

• 1. Foreign object causing channel corrosion. Indentation. Scratches: Clean the related parts and use clean grease.
• 2. Groove spalling: fatigue wear, replace the bearing

Irregular foreign object sound

• 1. Foreign object intrusion: clean the related parts use clean grease.
• 2. Excessive clearance: pay attention to the fit and choose the right clearance.
• 3. Ball scars: ball fatigue spalling or foreign object jamming; replace the bearing.

Abnormal temperature rise

• 1. Too much lubricant: reduce the lubricant
• 2. Insufficient or unsuitable lubricant: increase or choose a suitable lubricant.
• 3. The creep of the fitting surface or sealing device needs to be bigger: correct the fitting surface of the bearing outer diameter or inner diameter, and change the sealing form.

High rotary vibration of the shaft

• 1. Spalling: fatigue spalling, replace the bearing
• 2. Poor assembly: Improve the shaft’s machining accuracy and the installation method.
• 3. Foreign matter intrusion: Clean the related parts use clean grease.

Lubricant leakage and discoloration

• 1. Excessive lubricant: Reduce the lubricant.
• 2. Foreign matter intrusion: Clean the related parts

After mounting the bearings, to check whether the mounting is correct, it is necessary to carry out a running check, and small machines can be rotated by hand to ensure the rotation is smooth. Check if there is any foreign matter. Scars. Check whether foreign objects, scars, or indentations cause any problems. Uneven rotating torque due to poor mounting or poorly machined mounting base. Small clearance. High torque due to sealing friction caused by installation error. If there is no abnormality, the power operation can be started.

Because large machinery cannot be manually rotated, no load starts immediately after the power is off, inertia running, and check for vibration. Sound. Whether the rotating parts have contact, etc., to confirm no abnormality in the power operation.

Disassembly of bearings

The bearings should be dismantled in a bright, dry, clean environment with the necessary tools and equipment prepared according to the bearing type.
If the bearing is to be used again after dismantling, the dismantling force should never be allowed to be applied through the rolling elements. Otherwise, both the rolling elements and the raceways will be crushed.
For non-separating bearings, first remove the looser-fitting bearing rings from the seat and then use a press to press the bearing out of the tight-fitting surfaces.
Disassembly of cylindrical bore bearings
a. Dismantling of small and medium-sized bearings
The small bearings can be dismantled from the housing by lightly striking the bearing rings with a hammer or using a puller. The claw disk of the puller should be placed on the bearing ring or adjacent element to be dismantled. Disassembly will be easier if the bearing configuration has been designed with slots in the shaft and bearing box shoulder for the puller jaws. Gripping the outer ring is also easier if the shoulder of the bearing housing has holes for the back-off screws.
To disassemble a small bearing with a retaining sleeve, loosen the nut a few turns and use a spacer to remove it by hammering. Directly utilize the back-off sleeve and rely on tightening the nut. If the operation is difficult, set up screw holes on the circumference of the nut, and rely on the top pressure screw to pull out the dismounting sleeve.

b. Disassembly of large bearings

For interference fit installation of large bearings generally needs a larger disassembly force, especially has been working for a long time and friction and corrosion of bearings need to use hydraulic method can be disassembled, of course, the configuration must already have the necessary oil channels and oil grooves can be done only when this is done.

Disassembly of cylindrical roller bearings (NU, NJ and NUP design) without a retaining edge or only with a retaining edge, you can use a special induction heater; this heater can quickly heat the inner ring and the shaft temperature will not rise, so the inner ring expansion, it is very easy to dismantle. The bore of the induction heater is set on the inner ring of the bearing, and the coil is energized with alternating current. At this time, an alternating magnetic field is generated around the coil. The magnetic line of force passes through the core of the bearing. It passes through the inner ring of the bearing, which generates an eddy current on the surface of the inner ring of the bearing and rapidly raises the temperature of the inner ring.
Heating is due to eddy current concentrated in the surface of the collar, so the surface temperature is the highest the deeper the temperature from the surface is lower. When the bearing collar has been loosened on the shaft, cut off the power supply, stop heating and dismantle the bearing.
Disassembly of tapered hole bearings
a. Disassembly of small and medium-sized bearings
For bearings mounted on the retaining sleeve, the nut can be loosened for a few turns first and then disassembled with a hammer or a pipe-type unloading device or a special wedge, which can be disassembled by knocking a few times on the inner ring of the bearing with a cushion block. When dismantling the bearings on the sleeve, the locking device (shaft nut, end cap, etc.) should be removed from the bearings, and the sleeve should be screwed on the sleeve threads and tightened until the sleeve is loosened. If the threaded part of the sleeve extends out of the end of the shaft or the shoulder of the shaft, the thick-walled support ring as thick as possible can be inserted inside the hole of the sleeve to prevent the sleeve from deforming and the threads from being damaged when the nut is screwed on.        
b. Dismantling of large bearings
To dismantle large bearings mounted on tapered journals, tightening sleeves or unloading sleeves, hydraulic nuts or hydraulic pressure can be used. Hydraulic nut or oil pressure method can be used. By adding hydraulic oil to the oil hole in the tapered shaft, the bearing will immediately separate from its seat. For this purpose, some form of stop, such as a shaft nut or end plate, must be provided to limit the axial release of the bearing.

Maintenance of bearings

The life of a bearing is the number of revolutions or hours a bearing will experience before pitting occurs under a given load. Bearings within this life should experience initial fatigue damage on any of their bearing rings or rolling elements.
However, in our daily practical use, it can be observed that in the same working conditions of the appearance of the same bearing, the actual life is very different. Many factors affect the service life of bearings; today, a brief introduction to the maintenance of bearings, rust on the bearing service life of what effect?

Bearing maintenance cycle

How often should bearings be maintained? Theoretically, bearings can be used for 20,000-80,000 hours, but the specific life depends on the wear and tear in the use process, the work’s intensity, later maintenance, and so on.

How to maintain bearings

For bearings to give full play and maintain their proper performance for a long period, it is necessary to perform regular maintenance (periodic inspection). Proper periodic inspection, early detection of faults and prevention of accidents before they occur are very important to improve productivity and economy. Custody bearings in the factory are coated with the appropriate amount of anti-rust oil and packaged in rust-resistant paper; as long as the package is not destroyed, the quality of the bearings will be guaranteed. But for long-term storage, to be in a humidity below 65%, the temperature is about 20 ℃ under the conditions, stored on the shelf above the ground 30 cm is appropriate. In addition, the storage place should avoid direct sunlight or touch with cold walls. When cleaning the bearings and removing them for inspection, first record their appearance using photography or other methods. In addition, the amount of remaining lubricant should be confirmed, the lubricant should be sampled, and then the bearing should be cleaned.

Steps for bearing maintenance

• 1. Bearings strictly implement regular replacement; replacement cycle should be based on the bearing operating conditions reasonably set;
• 2. New bearings must be checked before use. Check that the contents of the packaging (preferably with instructions and certificates of conformity) are intact; identification (factory name, model) is clear; appearance (corrosion, damage) is good;
• 3. The inspection of qualified new bearings, in general conditions of use (more than 2 poles motor) cannot be cleaned; new sealed bearings need to be cleaned.
• 4. Bearings in the oil change before the bearing cover and bearings must be cleaned. Cleaning is divided into rough washing and fine washing, rough washing oil for clean diesel or kerosene fine washing oil for clean gasoline.
• 6. Bearing cleaning is completed; hand rotation should be flexible with hand radial and axial shaking can be initially judged whether loose or clearance is too large. If necessary, check the clearance. The ball or roller frame and other serious wear and tear, corrosion and metal spalling should be replaced.
• 7. Bearing cleaning after inspection, with a white cloth dry cleaner (or dry), add into the qualified grease. Adding different grease types in the same bearing is not allowed.
• 8. When refueling, it is forbidden to have dust in the surrounding environment; refuel with clean hands, slowly rotate the whole bearing with one hand, and press the oil into the bearing cavity with the middle finger and forefinger with the other hand. Add one side and then the other side. According to the number of poles of the motor, remove the excess grease.
• 9. Bearing and bearing cover oiling quantity: bearing cover oil quantity is 1/2-2/3 of the capacity of the bearing cover (motor pole number is high and take the upper limit); bearing oil quantity is 1/2-2/3 of the inner and outer ring cavity of the bearing (motor pole number is high and take the upper limit).
• 10. Oil filling and oil discharge holes in the motor end cover in the oil change must also be cleaned to keep the channel open. Oil filling hole must be filled with oil when refueling.
• 11. There are oil-filling holes in the motor must be regularly replenished oil. Oil replenishment cycle according to the motor operating requirements and operating conditions to determine (general 24-hour operation of the two-pole motor 500 hours).
• 12. When replenishing oil, the oil replenishment port must be clean. The amount of oil replenishment is limited to only a 2℃ increase in bearing temperature (2-pole motors with oil guns to inject oil twice quickly, observe for 10 minutes, and decide whether to continue to add according to the situation).
• 13. Bearing disassembly must ensure that the stress point is correct (shaft on the inner ring force, end cap inner and outer ring force) and that the force is uniform. The press-in method (small motors) and hot set method (large surplus and large motors) are best.
• 14. Bearing installation, the contact surface is evenly smeared with a little grease. Bearing installation must check the bearing inner ring and shoulder clearance (no gap is good).
• 15. Bearing hot set method of heating temperature control at 80 to 100 ℃, 80 to 100 ℃ time control within 10 minutes. Oil heating to ensure the use of non-corrosive thermal stability of good mineral oil (preferably to use transformer oil), oil and containers should be clean. In the oil tank from the bottom of the 50 to 70 mm set metal mesh, bearings are placed on the network; large bearings should also be hooked up.
• 16. Regular inspection of the motor, record the motor operating conditions (motor vibration, motor and bearing temperature, motor running current). General 75 KW above two pole motor once a day. When abnormal operating conditions to strengthen the inspection and inform the relevant parties.
• 17. All the maintenance work of bearings must be recorded as the basis for setting the periodic replacement cycle of bearings and determining the quality of bearings.

Bearing cleanliness

Bearing cleanliness on the bearing life is quite big bearing cleanliness the higher, the longer life, different cleanliness of the lubricating oil on the ball bearing life has a impact. Therefore, improving the cleanliness of lubricating oil can prolong the life of bearings; in addition, if the lubricating oil contains dirt particles controlled in the 10um below, bearing life is also multiplied.

• (1) The impact of vibration: cleanliness seriously affects the vibration level of the bearing, especially high-frequency band vibration is more significant. High cleanliness bearing vibration speed value is low, especially in the high-frequency band.
• (2) The effect on noise: the bearing lubricating grease in the dust on the noise impact has been tested, proving that the more dust the greater the noise.
• (3) The impact on lubrication performance: bearing cleanliness decline not only affects the formation of the lubricant film but also causes the deterioration of the grease and accelerates its aging, thus affecting the lubricating properties of the grease decline.

Bearing rust prevention methods

• 1. Surface cleaning: cleaning must be based on the nature of the surface of the rust-proof material and the conditions at the time; select the appropriate method. Generally used solvent cleaning method, chemical treatment cleaning method and mechanical cleaning method.
• 2. Surface drying after cleaning can be filtered dry, compressed air blow dry or 120-170 ℃ dryer for drying, and can also be used to clean gauze dry.
• 3. Immersion method: some small items are immersed in antirust grease, cross-tapered roller bearings so that the surface adheres to a layer of antirust grease method. The thickness of the film can be achieved by controlling the temperature or viscosity of the antirust grease.
• 4. Brush coating method: It is used for outdoor construction equipment or specially shaped products unsuitable for soaking or spraying, and attention should be paid to not generating piling up when brushing and preventing coating leakage.
• 5. Spray method: some large-scale antirust products cannot be coated with oil by immersion method, and the rotary table bearings are generally sprayed with filtered compressed air at about 0.7Mpa pressure in air-clean places. The spray method applies to solvent-diluted antirust oil or a thin layer of antirust oil but must be used to improve fire prevention and labor protection measures.

Be careful bearing descaling cannot use the following kinds of acid: sulfuric acid, hydrochloric acid, dilute sulfuric acid, and dilute hydrochloric acid because these acids will destroy the good metal parts, so these kinds of liquids can never be used! Several other liquids in daily life can remove rust without harming the good metal parts but with varying results. The first is dilute oxalic acid; the ratio of dilute oxalic acid to water is 3:1, dilute oxalic acid 3, water 1. This is slower, but the results are very good and sold everywhere. The second is gun oil, also called mechanical rust remover oil, not so good to buy; this oil removes rust quickly and works very well.

Solutions for bearing manufacturing: Processing of the main parts of the bearing

The main parts of bearings generally include: the inner ring, outer ring, rolling elements (such as balls, cylindrical rollers, tapered rollers, etc.) and cage (or called “cage”).

The following is the basic processing of the main parts of the bearing:

The machining process of bearing collar

Bearing inner ring and outer ring processing according to the raw materials or blank form of different, which can be divided into the following three processes before turning, the whole process is: bar or tube material (some bars need to be forged and annealed, annealed) → Turning → Heat treatment → Grinding → Finishing or Polishing → Final inspection of the parts → Rust → storage → (to be combined assembly)

Material selection and blank preparation:

• Bar or tube material selection: Selection of suitable steel or alloy as raw material to meet the performance requirements needed for bearings.
• Forging: Some bars need to be forged to improve their internal structure, uniformity and strength of the material.
• Annealing: After forging, the material may need to undergo an annealing process to eliminate stresses generated during forging and improve the material’s machinability.
• Normalizing: This process is used to adjust the hardness of the material to make it more suitable for subsequent machining.

Turning: The pre-treated blank is turned to remove surface irregularities from the blank and machine it to the designed geometry.
Heat treatment: The purpose is to improve the hardness and toughness of bearing rings. Commonly used heat treatment methods are quenching, tempering and so on.
Grinding: The collar, after turning is ground to achieve the required size and accuracy.
Fine grinding or polishing: Further, it improves the surface quality and precision of the collar. This step ensures the bearings have good contact and low friction during operation.
Final inspection of parts: Performs a quality check on the completed machined collar to ensure it meets all design and performance requirements.
Rust prevention: They are usually given a surface treatment, such as anti-rust oil, to prevent bearing rings from rusting during storage and transportation.
Inventory: The final inspected bearing rings are stored and are waiting to be assembled or shipped.
Fitting (if required): In some cases, bearing rings must be assembled with other parts, such as rolling bodies, cages, etc., to form a complete bearing.
The whole process should ensure high precision and quality output because the performance of the bearing is directly affected by the quality of its components.

Bearing steel ball processing

The processing of steel balls is also different according to the state of raw materials, which can be divided into the following three kinds of processes before the thwarting or light ball. The process before the heat treatment can be divided into the following two kinds of processes, the whole process is as follows: cold punching of rods or wires (some rods need to be punched after cold punching the ring belt and annealing) → thwarting, rough grinding, soft grinding or light ball → heat treatment → hard grinding → grinding → grinding → grinding or polishing → final inspection of the grouping → rustproofing and packaging →Stocking (to be assembled).

The processing of bearing steel balls involves cold working, heat treatment and grinding to ensure that the balls achieve the required precision and surface finish. The following is a detailed explanation of the above machining process:

• Cold punching of bar or wire: This is the initial process whereby a steel bar or wire is shaped into a steel ball in a prepared form through the cold punching process.
• Ring Banding and Annealing (if required): In some cases, the cold punched bar may require further processing, such as ring banding and annealing, to prepare it for the next step.
• Thwarting, rough grinding, soft grinding or bright balling: These are cold-working processes designed to provide the desired roughness and shape to the steel ball. Thwarting is usually used to remove excess material, while rough and soft grinding improves surface finish and shape accuracy.
• Heat Treatment: This is a vital process whereby the microstructure of the steel ball is altered by high temperature treatment, thereby increasing its hardness and toughness.
• Hard grinding: After heat treatment, a hard grinding process is carried out to ensure the steel balls’ shape accuracy and surface finish.
• Fine grinding: further optimize the surface finish and precision of steel balls.
• Fine grinding or lapping: This is the final process to ensure that the steel balls meet the highest standards of accuracy and finish.
• Final Inspection and Grouping: At the end of the process, steel balls are subjected to a final inspection to determine their quality and are grouped according to size, accuracy and other characteristics.
• Rust prevention and packaging: To prevent oxidation and corrosion of steel balls, they must be treated with rust prevention and then packaged appropriately.
• Storage (to be assembled): After all the above processing steps, the steel balls will be stored, waiting for subsequent use or assembly.

The process of processing bearing steel balls is designed to produce high-quality, high-precision steel balls to meet the needs of various bearings and other applications.

Processing of bearing rollers

The processing of rollers varies according to different raw materials which the process before heat treatment can be divided into the following two kinds of processes; the whole process is as follows: bar turning or wire cold upsetting after stringing the ring belt and soft grinding → heat treatment → stringing the soft point → rough grinding OD → coarse grinding end surface → final grinding end surface → fine grinding OD → final grinding OD → final inspection grouping → rust prevention, packaging → warehousing (to be combined with the set of assembly).

• String ring belt and soft grinding after bar turning or wire cold heading: Starting from the original metal bar or wire, the initial roller shape can be formed by turning or cold heading. This is followed by soft grinding to give a smoother surface.
• Heat Treatment: This step hardens the bearing rollers to increase their durability. This usually involves both quenching and tempering.
• String Soft Point: The sorting and organization of the rollers in preparation for subsequent machining.
• Rough Grinding OD: Preliminary grinding of the outer diameter of the roller to approximate the desired size.
• Rough grinding of the end faces: Preliminary grinding of the two end faces of the roller.
• Final grinding of the end faces: Precise grinding to the required dimensions and surface roughness.
• Fine grinding OD: More precise grinding of the outer diameter of the roller.
• Final grinding OD: final grinding of the outer diameter to ensure it meets all dimensional and roughness requirements.
• Final inspection grouping: All finished rollers are inspected and grouped according to size and quality.
• Rust prevention and packaging: To prevent the rollers from rusting, they will be treated with rust prevention and then packaged.
• Storage (to be assembled): The finished rollers are stored and are waiting to be assembled.

Throughout the process, the control of each step is critical because it will directly affect the quality and performance of the rollers.

Cage machining process

Cage processing, according to the design structure and raw materials, can be divided into the following two categories:
(1) Sheet material → shearing → punching → stamping forming → shaping and finishing → pickling or shot blasting or stringing → final inspection → rust prevention, packaging → storage (to be assembled)

• Sheet: This is the raw material for processing, usually a flat metal plate.
• Shearing: Shearing the sheet to the required size.
• Stamping: The basic shape of the bearing cage is stamped out using a die.
• Stamping: Stamping to form a specific shape and size.
• Shaping and Finishing: Further processing of the stamped product to ensure it reaches the required dimensions.
• Pickling, Shot Peening or String Lighting: Remove oxidized layers and impurities from the product’s surface and make it smooth.
• Final Inspection: Check the quality of the products to ensure that they meet the production standards.
• Rustproofing and packaging: Rustproof the product and package for subsequent assembly or sale.

(2) The processing of solid cage: solid cage processing, depending on the raw materials or bad and different, can be divided into the following four types of blanks before turning; the entire process is: bar, tube, forging, casting → car ID, OD, end face, chamfering → drilling (or drawing holes, bores) → pickling → final inspection → rust prevention, packaging → warehousing (to be assembled).

• Raw material selection: Select different raw materials according to the needs, such as bars, tubes, forgings, castings and so on.
• Turning: Use a lathe to process raw materials to form the required inner diameter, outer diameter, end face and chamfer.
• Drilling, broaching or boring: Machining holes in the cage to facilitate subsequent assembly.
• Pickling: removes oxidized layers and impurities from the surface of the product.
• Final Inspection: Ensure the quality of the product as in the case of final inspection in sheet metal processing.
• Rustproofing and packaging: Preparation of the product for final sale or assembly.

It is important to note that specific processes may vary slightly depending on production conditions, materials and equipment, but the above description should provide a general framework. If you need more specific information or have other questions, please let me know.

Quality Inspection Solution for Bearings: How to test the quality of bearings?

Bearing is a critical component in machinery, and its quality directly affects the performance and life of the whole equipment. To ensure the good performance of the bearings, we can test them from many angles. The following are some common methods to detect the quality of bearings:

• Appearance inspection: Check for cracks, rust, scratches or other damages on the bearing surface. Check the appearance of rolling elements, cages, inner and outer rings and other major components.
• Dimension Measurement: Use measuring tools (such as calipers, micrometers, height rulers, etc.) to check the various dimensions of the bearings to ensure that they meet the design specifications.
• Cleanliness Inspection: Carry out a cleanliness inspection on the bearings to ensure no pollution and impurities inside.
• Rotation Inspection: Rotate the bearings manually or by machine to check whether they rotate smoothly and whether there are abnormal sounds or vibrations.
• Vibration test: Use a vibration tester to test the bearings and check whether their vibration level meets the standard.
• Sound test: Use a sound detector to check for abnormal sounds when the bearing is running, such as clicking and friction.
• Clear Liquid Inspection: Put the bearings into transparent liquid and observe whether bubbles or other foreign substances are floating out to detect whether there is any contamination inside the bearings.
• Hardness test: The rolling elements and rings of the bearing are hardness tested to ensure that they meet manufacturing standards.
• Use of special equipment: Certain high-end applications may require special equipment, such as ultrasonic testing, magnetic particle testing, etc., to ensure the integrity and quality of the bearing.
• Material analysis: Spectral analysis or other methods are used to check the composition of the bearing material to ensure it meets design requirements.
• Grease analysis: If the bearing is pre-filled with grease, check the type and quality of the grease to ensure it meets the application’s requirements.
• Load and Life Tests: Actual load and life tests are performed on bearings in specialized test equipment to verify their performance.
• Sealing performance check: For bearings with seals, check their sealing performance to ensure that they can prevent the entry of contaminants and keep the grease from loss.
• Packaging and marking: Ensure that the packaging of the bearings is intact and the markings on them are clear and correct so that users can understand their specifications and methods of use.

It is recommended that before purchasing and using the bearings, the corresponding quality checks mentioned above should be carried out according to the requirements of your application. If possible, purchase from a reputable bearing manufacturer or distributor, which is more likely to ensure the quality of the bearings.

Bearing selection solutions: How to select bearings?

Correct bearing selection is essential to ensure the normal operation of the equipment. Extend the service life. Reducing maintenance costs is critical. The following are general bearing selection steps:
Step 1: Understand the conditions of use of bearings

• 1. The main function and structure of the host: for example, motor-spindle, conveying speed and torque.
• 2. Where the bearings are to be mounted.
• 3. The size and direction of the bearing. Direction. Nature. Whether shock loads, etc.
• 4. The lubrication conditions of the bearing.
• 5. The environmental conditions surrounding the bearing, e.g. Corrosivity, cleanliness. Cleanliness. Humidity. Ambient temperature. Heat dissipation, etc.
• 6. Operating speed of the bearing. Operating temperature.

Step 2: Selection of bearing structure

• 1. Dimensional space;
• 2. Load carrying capacity, including size. Direction and nature;
• 3. Limiting speed;
• 4. Rigidity;
• 5. Tolerance classes;
• 6. Centering performance;
• 7. Mounting and dismounting requirements;
• 8. Price and availability;
• 9. Form of support.

Step 3: Selection of bearing size

• 1. Service life and reliability requirements;
• 2. Basic dynamic (static) load ratings;
• 3. Bearing size;
• 4. Limiting speed. 5. permissible axial load capacity (for radial bearings);
• 5. permissible axial load carrying capacity (for radial bearings).
• 6. Safety coefficients;
• 7. Dimensional space.

Step 4: Selection of bearing accuracy

• 1. The function and structure of the main machine: whether it is a precision machine such as a machine tool or ordinary equipment. 2. The precision of the shaft and housing;
• 2. Shaft and housing accuracy;
• 3. Friction torque;
• 4. Rotational speed;
• 5. Vibration and noise;
• 6. Rigidity. 7. Clearance;
• 7. Clearance.

Step 5: Bearing Clearance Selection

• 1. Shaft and housing construction and material;
• 2. Fit;
• 3. ambient and operating temperatures of the bearing;
• 4. The operating speed of the bearing
• 5. The amount of load to which the bearing is subjected;
• 6. The permissible deflection of the collar.

Step 6: Selection of cage structure

• 1. The working speed of the bearing;
• 2. Vibration and noise;
• 3. The nature of the loads: whether shock loads, etc.;
• 4. Lubricant and method of lubrication;
• 5. Cage guidance.

Step 7: Lubrication Selection

• 1. Operating speed of the bearing;
• 2. The nature of the bearing load. Nature. 3;
• 3. Lubrication method. 4. Sealing method;
• 4. Sealing method.

Step 8: Selection of mounting and dismounting

• 1. Fits;
• 2. Mounting and dismounting methods.

Step 9: Consult the manufacturer’s catalog and technical data
Detailed bearing information is usually provided in the manufacturer’s catalogs and technical instructions and can be used as a reference.
Step 10: Testing and verification
It is recommended to conduct tests and validations before formal purchase and use for important or special applications.
Step 11: Communicate with suppliers
Communicating with bearing suppliers or manufacturers to get their suggestions and opinions may lead to a more suitable solution.
Correct selection of bearings cannot only ensure the stable operation of machines and equipment but also extend the service life of the equipment, reduce maintenance costs and improve work efficiency.

Bearing manufacturer selection program: how to choose the right bearing manufacturer?

Selecting the right bearing manufacturer is critical to ensure product quality, cost control and supply chain stability. The following are options and suggestions for selecting a bearing manufacturer:
Quality and Reputation:

• Obtain manufacturer certification information, such as ISO 9001 or other relevant standards.
• Ask for manufacturer references and customer feedback.
• If possible, conduct an on-site audit to assess their manufacturing processes and quality control procedures.
• Examine the manufacturer’s historical return rates and record of quality issues.

Price:

• Get quotes from multiple manufacturers to compare.
• In addition to unit price, consider other costs such as transportation, taxes, etc.

Delivery time and reliability:

• Evaluate the manufacturer’s production capacity and delivery record.
• Ensure the manufacturer can meet your delivery requirements, especially during high-demand periods.

Service and support:

• Choose a manufacturer that offers good after-sales service.
• Consider whether the manufacturer offers technical support and training.
• Understand the manufacturer’s process for handling quality issues and returns.

Technical capabilities:

• If your application requires special or customized bearings, ensure the manufacturer has the relevant R&D and production capabilities.
• Evaluate the manufacturer’s frequency of technology updates and new product development capabilities.

Long-term partnership potential:

• Consider the manufacturer’s stability, history and growth potential.
• Understand the manufacturer’s long-term strategy and willingness to work with you.

Geographic location:

• Proximity to a manufacturer may reduce transportation costs and time.
• But don’t sacrifice quality or other key factors simply because of location.

Contract terms:

• Ensure the contract is clear, fair, and contains all relevant details such as price, delivery times, quality standards, etc.
• Consider the need for long-term contracts to ensure price and supply stability.

Environmental and social responsibility:

• Consider the manufacturer’s environmental protection strategy and social responsibility practices.
• Select manufacturers committed to sustainable production and have a good track record of social responsibility.

Risk management:

• Understand the manufacturer’s risk management strategies, such as alternate production lines and raw material reserves.
• Consider whether the manufacturer can respond to unforeseen events, such as natural disasters, political instability, etc.

When choosing a bearing manufacturer, it is advisable to consider not only price but also to fully evaluate all aspects of the manufacturer to ensure that the manufacturer you choose can provide you with high-quality, stable and reliable services.