Knowledge about Precision Bearing

Knowledge about Precision Bearing

Definition of Precision Bearing

Bearings with precision ratings P6, P5, P4, P2 normally be called precision bearings.

The performance of precision bearings requires the rotating parts to have high run out accuracy, high-speed rotation and small friction and friction changes.

Precision Rating of Precision Bearing

Precision bearing-Precision rating>P0;

Super precision bearing (Ultra precision bearing)-Precision Rating≥P4, P4S.

Precision ratings are divided into: P0, P6, P5, P4, P2 according to the ISO classification standards.

The grades increase in turn, where P0 is ordinary precision, and the others are precision grades.

Of course, different classification standards, different types of bearings, their classification methods are different, but the meaning is the same.

Precision Bearing Features

  • High Precision
  • High-speed Performance
  • Higher Running Accuracy
  • High System Rigidity
  • Longer Service Life
  • Absolute Operational Security
  • Minimize Noise, Vibration and Heat Generation
  • Optimized Customer Profit

Precision Bearing Applications

Precision bearings are particularly suitable for applications involving the highest requirements for guidance accuracy, such as applications as below.

  • Metal Cutting and Woodworking Machinery Spindles.
  • Other Machine Spindles: balancing Machine Tools, Main Spindles, feed spindles, linear axes in machine tools etc.
  • High Speed Rolling Mills
  • Printing Machinery
  • Precision Ball Screws
  • Live Centers
  • High Speed Turbochargers
  • Vacuum Pumps
  • Racing Cars
  • Boat Gyrostabilizers
  • Machine Components for the Semiconductor Industry
  • Marine Vessels
  • Rotary Tables

Famous Precision Bearing Brand


About NSK Precision Bearing

NSK precision bearings delivery high performance, long life features that enhance the value of industrial machinery while achieving environmental friendliness and energy conservation.

It provides problem-solving solutions and an extensive product lineup for mechanical industry applications and manufacturing operations, includes machine tools spindles, live centers, ball screw support and motor spindle applications.

NSK Precision Bearing Series Available

  • Standard series, ROBUST series, ROBUST Wide series
  • 7000 series, 7900 series
  • BNC series, BGR series, BAR series, BTR series
  • BNR 19 series, BNR 10 series, BNR29 series, BNR20 series (18 contact angle)
  • BER 19 series, BER 10 series, BER29 series, BER20 series (25 contact angle)
  • TAC series
  • N series, NN series


About FAG Precision Bearing

FAG super precision bearings set standards in machine tools, in the textile industry, in woodworking machinery and whatever extreme demands are placed on reliability, running accuracy and high speeds, individually or in combination. Due to its comprehensive product range, it is possible to achieve optimum designs for all bearing positions and applications.

FAG super precision angular contact ball bearing fulfil the P4S standard. Super precision cylindrical roller bearings and axial angular contact ball bearings are manufactured in accordance with the SP or UP accuracy standard that are matched to machine tool requirements.

FAG Precision Bearing Series Available

  • B70 series, B719 series, B72 series (standard spindle bearings, steel balls)
  • HC70 series, HC719 series, HCB70 series, HCB719 series, HCB72 series, XC70 series, XC719 series(Hybrid spindle bearings, ceramic balls)
  • HS70 series, HS719 series(Spindle bearings with small balls, steel balls)


About SKF Precision Bearing

Build in year 1907 in Sweden, SKF has grown to become a global industrial knowledge leader.

SKF super precision bearings that generate low levels of frictions are, therefore, best suited for high speed applications due to their corresponding low operating temperatures.

At the same time, SKF’s complete assortment of super precision bearings is designed for machine tool and other applications that require a high level of running accuracy at high to extremely high speeds.

SKF Precision Bearing Series Available

  • 718 series, 719 series, 70 series, 72 series
  • BSA series, BSD series (single direction angular contact thrust ball bearings for screw drives)
  • BEAS, BEAM series(double direction angular contact thrust ball bearings for screw drives)
  • NRT series (axial-radial cylindrical roller bearings)
  • NN series, NNU series
  • BTW series, BTM series

Precision Bearing Type

Super Precision Angular Contact Ball Bearing

Super precision angular contact ball bearing is with solid outer and inner rings, ball and cage assemblies and solid window cages, due to its narrow tolerances, it is very suitable for spindles and machine tools.

Super Precision Cylindrical Roller Bearing

Super precision cylindrical roller bearings comprise solid outer rings and inner rings, cylindrical roller and cage assemblies with cages made from polyamide, brass.

The outer ring is removable and can thus be mounted separately from the rest of the bearing package.

The bearings facilitate bearing arrangements with very high precision, high radial rigidity and very high load carrying capacity.

It suitable for situations that both high precision and high radial load required.

Double Direction Angular Contact Thrust Ball Bearing

Double direction angular contact Thrust ball bearing comprises solid shaft locating washers, a spacer ring, a housing locating washer and ball and cage assemblies with solid cages.

It Is highly rigid, axially preloaded super precision bearings with restricted tolerances for the bearing arrangements of precision spindles in machine tools.

High axial loads and radial forces can be supported.

Hybrid Bearing

Hybrid spindle bearings have bearing rings made from steel and rolling elements made from ceramic (silicon nitride Si3N4).

It can achieve very high speeds, have lower friction and heat generation, a longer cooperation life , place less strain on the lubricants and are insensitive to lubricant starvation.

Precision Bearing Installation Notice

1. Since the precision of the precision bearing itself is within 1μm, it is required to have high dimensional accuracy and shape accuracy with its matching parts, especially the accuracy of the mating surface must be controlled within the same level as the bearing. This is very important, and also Most easily overlooked.

It must also be noted that if the matching parts of the precision bearing do not meet the above requirements, the precision bearing will often have an error that is several times larger than the original bearing error after installation, or even more than 10 times the error. It is completely impossible to be a precision bearing because of the matching machine. The error of the parts is often not simply superimposed on the error of the bearing, but added after being enlarged by different multiples.

2. For the matching of precision bearings, in order to ensure that the bearings do not produce excessive deformation after installation, the following must be achieved:

(1) The roundness of the shaft and the seat hole and the verticality of the shoulder should be required in accordance with the accuracy of the bearing.

(2) It is necessary to accurately calculate the interference amount of the rotating ferrule as well as the appropriate amount of the fixed ferrule.

The burning interference of the rotating ferrule should also be smaller within the possible range. As long as the effect of thermal expansion at the working temperature and the effect of centrifugal force at the maximum speed are ensured, it will not cause creep or slippage of the tight-fitting surface.

According to the size of the working load and the size of the bearing, the fixed ring selects a very small clearance fit or an interference fit. Too loose or too tight is not conducive to maintaining the original precise shape.

(3) If the bearing runs at high speed and the working temperature is high, pay special attention to the fit of the rotating ferrule not to be too loose to prevent eccentric vibration, and there must be no gap in the fit of the fixed ferrule to prevent the ferrule from being under load. Deforms downward and excites vibration.

(4) The condition of adopting small interference fit for the fixed ring is that both sides of the matching surface have high shape accuracy and small roughness, otherwise it will cause installation difficulties and disassembly more difficult. In addition, the influence of the thermal elongation of the spindle needs to be considered.

(5) The main shaft using paired double angular contact ball bearings usually has a lighter load. If the fit interference is too large, the internal axial preload will be significantly too large, which will cause adverse effects. The main shaft of the double-row short cylindrical roller bearing and the main shaft of the tapered roller bearing have a relatively large load, so the fit interference is relatively large.

3. To improve the actual matching accuracy, in order to improve the actual matching accuracy when the bearing is installed, it is necessary to use measurement methods and measurement tools that do not deform the bearing to perform actual precision measurement of the matching surface size of the inner hole and outer circle of the bearing. All the measurement items related to the inner diameter and outer diameter are measured, and the measured data is fully analyzed. Based on this, the size of the bearing installation part of the shaft and the seat hole is precisely matched.

In the actual measurement of the size and geometry of the shaft and the seat hole, it is carried out under the same temperature conditions as when measuring the bearing.

In order to ensure a higher actual matching effect, the roughness of the matching surface of the shaft and the seat hole and the bearing should be as small as possible.

When making the above measurement, on the outer circle and inner hole of the bearing, and on the surface of the shaft and the seat hole, on the two sides close to the assembly chamfer, two sets of marks that can show the direction of the maximum deviation are made to show the direction of the maximum deviation. When assembling, align the maximum deviation of the two matching parties in the same direction, so that the deviation of the two parties can be partially offset after assembly.

The purpose of making two sets of orientation marks is that the compensation of deviation can be considered comprehensively, not only to improve the rotation accuracy of each support at both ends, but also to obtain part of the coaxiality error of the seat hole between the two supports and the journals at both ends. eliminate. The implementation of surface strengthening measures on the mating surface, such as sandblasting, using a precision plunger with a slightly larger diameter to plug the primary inner hole, etc., are all conducive to improving the accuracy of the mating.

Why choose Todaybearing?

About Todaybearing

SDVV BEARING GROUP LIMITED (Todaybearing owner company), established in 1986, is professional in providing bearings replacement and solutions only.

The range covers all kinds of super precision bearings, rolling mill bearings, ball bearings, roller bearings, bearing units, guide rail and slide block etc.

we are also agents for many world-famous bearings, the bearing brands include SKF bearings, FAG bearings, INA bearings, TIMKEN bearings, KBC bearings and a series of Japanese bearings (NSK, NTN, KOYO, IKO, NACHI, ASAHI, FYH, NMB, THK bearings, etc).

Quality, value and service are the cornerstones of our company, certificate of origin and certificate of quality can be provided.

In order to supply bearings in timely, we have set up many warehouses all over the world to store a large inventory of various bearings, which enables us to send bearings directly from stock and saves time spent in domestic transportation and export Customs clearance.

The above factors make us have a greater advantage over any other sources in supplying bearings and accessories.

Because we consist on providing quality bearings only, we have built long term cooperation with many bearings distributors and end-users from over 120+ countries, including the United States, Germany, Canada, Spain, Russia, Ukraine, Japan, South Korea, South Africa, Brazil, Middle East, South East Asia, Africa, and so on.

You may just feel free to contact us whenever you are in need of any kind of bearings.

It would be our great honor to develop business cooperation relationships with partners globally.

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