Your Credible Miniature Bearing Manufacturer

The LLG Miniature Bearing provides high-quality products and services to friends at home and abroad and works together with us to create a bright new future. 

  • LLG Miniature Bearing strictly selects industrial-grade quality, corrosion resistance, not easy to rust.
  • Our product is lightweight and durable, with high technical precision.
  • We provide a reasonable design, environmentally friendly, and easy to install.
  • LLG Miniature Bearing easily meets the needs of life and trust.
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    The LLG’s Miniature Bearing

    The LLG Miniature Bearing has gradually developed from twenty years ago to now has advanced automation equipment and sophisticated and comprehensive testing equipment. LLG Miniature Bearing company is relying on the business philosophy of integrity management, quality first, and sincere cooperation.

    Each set of LLG Miniature Bearing produced by the company has undergone multi-level inspection and selection to ensure that product quality fully meets international standards.

    LLG Miniature Bearing Series

    Miniature Bearing

    Diameter: 1.98 – 2.38 mm
    Outside Diameter: 6.35 – 7.94 mm
    Width (Open): 2.38 – 2.78 mm
    Width (Shielded): 3.57 – 3.57 mm
    Featuring: R1-4zz – R1-5zz Standard Miniature Bearing reduces friction and enables smoother rotation. This reduces energy consumption.

    Miniature Bearing

    Diameter: 3.16 – 3.97mm
    Outside Diameter: 6.35 – 12.7 mm
    Width (Open): 2.38 – 2.78 mm
    Width (Shielded): 2.78 – 4.37 mm
    Featuring: R144Jzzs – R155zzs Standard Miniature Bearing reduces friction and enables smoother rotation. This reduces energy consumption.

    Miniature Bearing

    Diameter: 4.76 mm
    Outside Diameter: 7.94 – 15.88 mm
    Width (Open): 2.78 – 4.98 mm
    Width (Shielded): 3.18 – 4.98 mm
    Featuring: R156zzs – R3Azz Standard Miniature Bearing reduces friction and enables smoother rotation. This reduces energy consumption.

    Miniature Bearing

    Diameter: 6.35 mm
    Outside Diameter: 9.53 – 19.05 mm
    Width (Open): 3.18 – 5.56 mm
    Width (Shielded): 3.18 – 7.12 mm
    Featuring: R168zzs – R4Azz Standard Miniature Bearing reduces friction and enables smoother rotation. This reduces energy consumption.

    Miniature Bearing

    Diameter: 7.94 – 12.7 mm
    Outside Diameter: 12.7 – 19.05 mm
    Width (Open): 3.97 – 5.56 mm
    Width (Shielded): 3.97 – 7.14 mm
    Featuring: R1810zzs – R1212zz Standard Miniature Bearing reduces friction and enables smoother rotation. This reduces energy consumption.

    Miniature Bearing

    Diameter: 1.98 – 2.38 mm
    Outside Diameter: 4.76 – 7.94 mm
    Width (Open): 1.58 – 2.78 mm
    Width (Shielded): 2.38 – 3.56 mm
    Featuring: FR1-4zzs – FR144zzs Flange Miniature Bearing can withstand hefty spiral loads and moderate push loads in the two ways.

    Miniature Bearing

    Diameter: 3.16 – 4.76 mm
    Outside Diameter: 7.94 – 12.7 mm
    Width (Open): 2.78 – 4.98 mm
    Width (Shielded): 3.56 – 4.98 mm
    Featuring: FR2-5zz – FR3zz Flange Miniature Bearing can withstand hefty spiral loads and moderate push loads in the two ways. It has an external ring spine to work with area in a lodging.

    Miniature Bearing

    Diameter: 6.35 – 9.53 mm
    Outside Diameter: 9.53 – 22.23 mm
    Width (Open): 3.18 – 5.56 mm
    Width (Shielded): 3.18 – 7.14 mm
    Featuring: FR168zzs – FR6zz Flange Miniature Bearing can withstand hefty spiral loads and moderate push loads in the two ways. It has an external ring spine to work with area in a lodging.

    Why LLG Miniature Bearing

    LLG Miniature Bearing generally refers to a our products with an inner diameter of 19 mm or an inch size of 1.0169.525 mm. Depending on the size and structure of the Miniature Bearing, the model labels of the world’s major bearing companies are slightly different.

    LLG Miniature Bearing, compact structure, small installation space, low starting torque. Often used for high-speed, low-noise products. Our LLG Miniature Bearings have high machining precision, and we can provide vacuum degassing bearing steel. We can provide stainless steel bearing LLG Miniature Bearing. We also provide flange LLG Miniature Bearing or non-standard bearing.

    Miniature Bearing Producing

    Desirable LLG Miniature Bearing Applications for your Business

    Cylinder Head Miniature Bearing
    Cylinder Head
    Mining Equipment Miniature Bearing
    Mining Equipment
    Agricultural Machine Miniature Bearing
    Agricultural Machine
    Rotary Encoder Miniature Bearing
    Rotary Encoder
    Precision Machine Miniature Bearing
    Precision Machine
    Electric Motor Miniature Bearing
    Electric Motor
    Fan Motors Miniature Bearing
    Fan Motors
    Cleaner Motor Miniature Bearing
    Cleaner Motor

    LLG - Your Professional Miniature Bearing

    The LLG Miniature Bearing

    Searching for rolling smoothly, quiet, and long time sustainable working miniature bearing? We offer our LLG Miniature Bearing for you.

    We, LLG Miniature Bearing a professional bearing provider. We have professional suppliers that can provide the best support no matter before or after cooperation. From raw materials to final LLG Miniature Bearing, good cost control and quality achieve sustainable development.

    The LLG Miniature Bearing has won praise from friends at home and abroad for its excellent product quality and accurate delivery. Our LLG Miniature Bearing are exported to many countries and regions, and the company also manufactures for many well-known domestic brands.

    LLG Miniature Bearing, high precision, low noise, low starting torque, can provide the structure and quality requirements according to customer needs.

    Furthermore, our LLG Miniature Bearing precision grade: P0, P6, P5, P4, P2, can offer small clearance bearing can be provided according to support needs.

    Contact us immediately!

    Miniature Bearings-The Ultimate FAQ Guide


    Do you know bearings are available in small and miniature sizes?

    In small machinery like laptops, drilling machine, clocks, and many rotary tools these miniature-sized bearings are used to keep the parts moving.

    LLG bearings is working best to provide their customers with the supreme quality of bearings. 

    In this write-up, you will find necessary information regarding the specifications, types, and advantages of miniature bearings.

    Read further to know more!

    • What Is a Miniature Bearing? 

    Miniature bearing is a small-sized ball bearing that has an outer diameter of 30mm. Miniature bearings determine the rotational precision. 

    Miniature bearings are essential components used in various equipments and machines. Miniature bearings help in mechanical rotation, decrease the friction coefficient, and elevate the precision of movement. These bearings assist the shaft and rotate in a smooth way. 

    Miniature bearings have best usage in equipments which possess high operational speed. Miniature bearings produce lower buzz and vibration. Thus, the presence of frictional torque is reduced. Miniature bearings are also referred as micro bearings. 


    Miniature Bearing

    Miniature bearings have various metric sizes and external diameter is less than 9mm. 

    The miniature bearings are made up of:

    • Carbon steel
    • Ceramic
    • Stainless steel
    • Plastic

    2. What Are Three Types of Miniature Ball Bearing?

    The three main types of such ball miniature bearings are as follows: 

    • Flanged Radial Deep Groove Miniature Ball Bearing

    This kind of miniature bearing is a radial bearing and consists of flange characteristics on any single side of external hoop. Flange helps a lot in determining the location of axis for housing. 

    This kind of miniature bearing is made of stainless steel. It is categorized into opened, shielded and sealed form.

         2.  Radial Deep Groove Miniature Ball Bearing with a Snap Ring

    This kind of miniature bearing is also radial bearing and has retaining on any single side of external ring top. In this type, the ring finds the direction of axis for housing.

    This type is made of high carbon form of chromium steel. It has either shielded or opened type. 

       3. Ultra Thin Radial Miniature Ball Bearing

    The bore size of such kind of miniature bearing is larger than other such bearings. It is made of stainless steel material. 

    3. What Are Smallest Miniature Ball Bearings? 

    The smallest miniature ball bearings are those that have external diameter of 1.5mm and the thickness is around 0.65mm. 

    Such miniature ball bearings have pressed-steel structure of cage. Some smallest miniature ball bearings have been manufactured having diameter up to 2.2mm which works in devices of small precision. 

    The smallest miniature ball bearings can attain the size of 1.5mm external diameter, 0.5mm internal diameter

    Smallest Miniature ball bearing

    Smallest Miniature Ball Bearing

    4. What Is C Type Miniature Bearing?

    C type miniature bearing is a form of bearing which have the capability to work efficiently when a less internal clearance is required. 

    C type miniature radial contact bearing is supposed to make a ball-to-ball connection. This connection occurs while thrust load’s absence. C type miniature bearing can bear axial load in any direction. Axial load can be withstand only when the miniature bearings is properly installed. 

    In C type bearing, internal clearance is done when the balls have to make a connection with the raceways at some interfering angle and to resist the load. In filling slot, miniature balls junction is disturbed by axial load. 

    When the internal clearance is increased to a great extent than required, then the C type miniature bearings will have high thrust size. 

    In this way, miniature bearings should be placed against each other to reduce the axial load. Therefore, C type miniature bearing is more of angular contact rather than radial. 

    5. Which Miniature Bearing Is Used for High Speed?

    The miniature bearing which cannot wear out quickly and has an advantage of high operational speed is mostly used in machines. Miniature bearing which is do not collapse on high temperature and have high stiffness. 

    High precision miniature bearings are used which have:

    • Higher stiffness
    • High accuracy
    • Lower friction coefficient 
    • Less generation of heat
    • High rotational speed. 

    Higher precision miniature bearings are:

    • High speed deep groove ball bearings
    •  Angular contact ball bearings which must be in sealed form
    • Thrust ball bearings

    Miniature Roller bearings have rolling components such as centrifugal load. They can bear excessive load when it is applied on the external hoop raceways. 

    Angular Contact Ball Bearing

    In such type of ball bearings, the connection is decreased to a great extent on the external ring and increased on the internal ring. Due to different contact angle, the probability of slipping of ball is high on any one side of the ring. The stiffness is suffered due to uneven angle. 

    Centrifugal load is lowered when the balls of small mass are used. The higher modulus of elasticity of silicon-nitride gives a bearing of ceramic rolling parts greater stiffness. The miniature bearing having such qualities is designed for extremely high speed. 

    6. What Is the Difference between Heading And Miniature Bearing? 

    Heading is direction in which anything is pointing. It is clockwise through 359° and its value changes constantly due to floating of winds or anything and the things or vessels deviated from the place. Heading is also referred as where the knot is pointing. 

    Miniature bearing is a direction on either side of the bow. Bearing is an ambiguous term. Its’ an angle between the north or the object you are trying to look. It is the angle in degrees and also measured in mils. 

    Miniature bearings are of different types which are as follows:

    • Miniature Magnetic Bearing
    • Miniature True Bearing
    • Miniature Arbitrary Bearing

    7. Compass Miniature Bearings Vs True Miniature Bearings?

    Compass miniature bearings are such bearings which make use of all of the four directions on the compass to search alternated objects location. By such miniature bearing, the things between two-dimensional planes can be found easily. 

    True miniature bearings are type of bearings in which existing north is different to magnetic north. So, the angle made by survey line with the geographical north is true bearing of miniature bearings.

    8. What Are the Various Features of Miniature Bearing? 

    Miniature bearing are high speed bearings. They are present in both sealed and open form to avoid any damage. They are also sealed to prevent dust, dirt, moisture and corrosion. 

    They are sealed to avoid the grease leakage. Handling becomes easy when the miniature bearings are properly sealed to avoid any harm. 

    These bearing also consist of cage such as rubber or crown cage. Suitable cage is selected for miniature bearing which is effected by factors such temperature, speed and force applied. 

    Miniature bearings are also present in un-flanged and flanged form. 

    9. How Do You Determine Miniature Bearing Size with Dimension? 

    Miniature bearings are widely present in various equipments and heavy machinery of industries. 

    Miniature bearings are mostly evaluated by measuring their dimensions which should be in mm. You have to measure the thickness of the miniature bearing by seeing its margins. Margins show that the bearing is suitable in the cavity given. 

    You have to calculate the diameter of the central hole to determine either miniature bearing fit on the axle of machine or not. 

    Miniature bearings are used in equipments that have the capacity to carry light weight. Miniature bearings are also found in metric sizes. 

    d= internal diameter

    D= external diameter

    B/T= Width 

    Miniature bearing size is measure with the help of vernier calliper. The formula used is:

    OD × ID × W. (Miniature bearing)

    The dimensions of miniature bearing have various series such as 6200 and 6300 are mostly used. 

    Steps to measure

    1. The initial digit recognizes the miniature bearing form
    2. The next two numbers recognizes the dimension series. The earliest number determines the width whereas the other numbers determine the diameter of miniature bearing. 
    3. The last two numbers recognizes the size code of the miniature bearing hole. 

    10. How Small Can Miniature Bearings Get?

    The smallest internal diameter of small miniature bearing can be 0.6mm but it is of 1mm. The smallest bearing in the globe can get a size of 1.5mm in external diameter and 0.5mm is the value of diameter from inside. 

    Smallest miniature steel balls can attain diameter of 0.25mm. They can run even at a speed of 5000 revolution per minute (RPMS).

    Smallest sizes of miniature bearing

    Smallest Sizes of Miniature Bearing

    11. In Which Applications Miniature Bearings Can Be Used? 

    Miniature bearings find their use in various industrial machinery and equipments. As the world is growing at a faster pace, the need of efficient and durable miniature small bearings has increased to a great deal. 

    Applications are as follows:

    • Tiny rotary motors
    • Laptop cooling fans
    • Dental drills
    • Laser engraving
    • Small clocks
    • Soft drives
    • Stepper motors
    • Toy models
    • Fuel controls
    • Gyroscopes
    • Gear boxes
    • Anemometers
    • Robots
    • Massage chairs

    12. Why Chrome Steel Is the Best Material for Miniature Bearings? 

    Miniature bearings made up of chrome steel are available in variable sizes ranging from 1.5mm – 9mm. 

    Chrome steel is the best material in preparing miniature bearings because it can bear heavy load and produces no noise. It is also wear resistant. Chrome steel mostly contains high carbon and chromium (15%). 

    Chrome steel miniature bearings consisting of steel cages and proper lubricant can be used at a constant temperature of 120°C and has an increased temperature limit up to 150°C. These miniature bearings are unable to operate above 150°C because it becomes unable to bear the load given and they undergo dimensional changes. 

    Miniature bearings made of chrome steel are protected with special quality oil so that any impurity may not alter their working ability. 

    The benefit is that chrome steel miniature bearings can be delivered in both open/sealed forms. Chrome steel miniature bearings are also found in large sizes such as Teflon and rubber seals which are contact as well as in non-contact rubber seals. It is high attracted by magnetic due to chrome present in it. 

    Chrome steel miniature bearings also have a cage and are categorized as:

    • One-piece crown cage is used for small miniature bearings
    • Larger miniature bearings have two-piece rubber cage. 


    Chrome Steel Miniature Bearing

    13. At What Temperature Chrome Steel Is Used for Miniature Bearing?

    Chrome steel can operate best at 120°C for miniature bearings and can be applied at higher temperature of 150°C. Beyond, this temperature miniature bearing performance is affected.

    Miniature bearing can best operate at temperature less than 400°F and do not result in fatigue and cracks. Also, the functioning of miniature bearing is reduced and cannot bear excessive load. 

    14. Is Chrome Steel Safe for Corrosive Environment in Making Miniature Bearings?

    Chrome steel miniature bearing cannot be used in corrosive environment. 


    • Chrome steel is made of high carbon and low chromium content. 
    • Chrome steel is more exposed to corrosion and corrosive environment due to low chromium content. 

    Moisture, heat, and contamination cause failure in miniature ball bearing working made of chrome steel material. 


    15. Which Crown Cage Is Used in Miniature Ceramic Bearing?

    Cage or a retainer balances the ball spacing and also reduce torque, heat generation and protect from the corrosive environment. 

    Types of Crown Cages

    1. PTFE Crown

    PTFE crown cage is mostly used in miniature ceramic bearing. It is not exposed to corrosion. Best work at temperature of -190°C to 200°C. 

    1. PEEK Crown

    PEEK crown cage is used in miniature ceramic bearing. It can work best at temperature of -70°C to +250°C. It has higher resistance to corrosion. 

    Ceramic crown cage miniature bearing

    Ceramic Crown Cage Miniature Bearing

    16. What Design Attributes Are Needed for Miniature Bearings? 

    A variety of bearing and its types are available. The design attributes which must be followed for making miniature bearings are:

    • From a stock of several hundred lubricants, requiring the factory best lubricant
    • To facilitate mounting feature, exceed the internal hoop or flanged external rings
    • Various style of ball cages and their working ability to maintain the working of such miniature bearings
    • Rate of toleration
    • Miniature ring bearings and miniature ball bearings can be made from stainless steel, chrome steel and ceramics. Stainless steel used must be of 440C
    • Friction and torque error testing
    • Use of metal shields and seals to prevent from contaminants
    • When loading an application then the contact angle and deflection must be checked. 

    17. Which Size of Miniature Bearings Are Known As Instrument or Micro Bearing?

    Miniature bearings have various sizes. The miniature bearing having bore from 0.6mm-9mm is referred as micro or instrument bearing. 

    These miniature bearings are made of stainless steel, chrome steel to reduce the effect of corrosion. 

    Instrument bearing can carry radial as well as thrust load even at reduced torque movement. Instrument bearings are occur in both flanged and un-flanged forms. 

    Miniature bearings and instrument ball bearings, both occur in two types:

    • Deep Groove Miniature Ball Bearing
    • Angular Contact Miniature Ball Bearing

    Deep Groove Miniature Ball Bearing

    Deep groove miniature ball bearing is further categorized into major five parts.

    • Single-row deep groove miniature ball bearing

    It can assist both axial and radial loads. The junction of tracks is simple. Therefore, the friction and sound of vibration produced is less. 

    • Deep groove miniature ball bearing with flanged external ring

    This kind of miniature bearing has a flange hoop just like snap hoop on other various bearings. The flange found in it is distributed around the border of the external hoop (ring) and it upgrades the turning accuracy. The hole-shaft is cylindrical in shape which gives higher precision for efficient working of machines. 

    • Deep groove miniature ball bearing with extended internal hoop

    This kind of ring is of inch series. The internal rings are distributed evenly. Internal ring is larger than external ring. The value of internal ring is 1/64. 

    • Deep groove miniature ball bearing with extended radial thickness

    This kind of miniature bearing have thick external hoop. The shaft diameter is smaller than that of external diameter. 

    • Thin-segment deep groove miniature ball bearing

    This kind of miniature bearing has smaller radial thickness. Shaft size ranges from 10 to 15mm.

    Angular Contact Miniature Ball Bearing

    This kind of miniature bearing can support both radial and axial loads in a single direction. Angular contact miniature bearing is used in devices having greater operational speed and high rigidity.


    Miniature Angular Contact Ball Bearing

    18. For What Purpose Miniature Bearings Can Be Shielded?

    Miniature bearings can be supplied in both open form as well as closed (shielded or sealed) form. The role of shield or a seal is to protect the miniature bearings from contamination and lubricant (oil and grease) leakage and from the corrosive environment. 

    Types of shields 

    • Snap Ring Shield

    Shield can be bounded in external hoop with snap ring. There is not any connection between circumference of internal hoop and bore. There is a reduced chance that contaminant particles will enter. This shield results in reduce torque and noise. 

    • Rubber Seal 

    Rubber seal fitted steel is present in the external hoop of miniature bearing. The point of contact for the seal is DD. SS kind of junction is avoided. The disadvantage of junction with DD is that the level of torque increases. It does not allow the entry of any contaminated particle. 

    19. What Do You Know About Stainless-Steel Miniature Bearing? 

    Shaft of the stainless steel miniature bearing is available in various sizes such as 0.6mm-9mm. Stainless steel miniature bearing is also referred as micro or mini bearing.

    250°C is the constant operating temperature of stainless steel miniature bearing. 300°C is the best optimum temperature stainless steel bearings can achieve and above this temperature, they undergo deformation. 

    Stainless steel miniature bearing can be used in environment which is exposed to corrosion or rusting because of high tensile strength of steel. However, stainless steel is prone to strong acid and base. There is no need of oil or grease lubrication on their external raceways. 

    Stainless steel miniature bearing

    Stainless Steel Miniature Bearing

    20. What Type of Packing Is Necessary for Miniature Bearing?

    When the miniature bearing is manufactured and visualized, then they are put to packaging to avoid any moisture, contamination, dirt and debris. 

    Miniature bearing packaging primarily consists of:

    •  Clear plastic tube
    • Craft paper
    • Paper made of polythylene
    •  Plastic film of polythylene
    • Linen bags
    • Nylon tape

    21. What Is Preload and Why Is It Necessary for Miniature Bearing? 

    Preload is an axial or thrust force applied to the miniature bearing to align their hoop speedways. 

    Miniature bearing used in small motors are given an internal clearance to lessen the amount of vibration produced. 

    Purpose of Pre-loading

    • Pre-loading of miniature bearing is done to enhance the movement of rings in the axial and radial direction. 
    • Pre-loading the miniature bearing is done to reduce the friction and the level of vibration. 

    Methods of Pre-loading

    There are major ways in which preload of miniature bearing occur. These are:

    1. Preload of Constant pressure
    2. Preload of fixed position

    In preload of constant pressure, hoop absorbs the load of vibration and the volume of the rotating shaft changes due to temperature. This type of preload is done to avoid vibration (axial) produced. 

    In preload of fixed position, axial vibration or deflection produced is smaller than that of constant pressure preload. Fixed-position pre-loading results in greater stiffness. 

    Preload of miniature bearing

    Preload of Miniature Bearing

    22. What Do You Know About Handling of Miniature Bearing? 

    Careful handling of miniature bearing is essential after manufacturing. 

    Miniature bearing require clean environment for their usage. 

    Assembly of miniature ball bearing

    When miniature ball bearing is placed on shaft or housing then the pivot point have to be same and should be placed at perfect right angle. In interacting fits, the external and internal hoop must collide at right angle and the amount of load should be less. 

    When fit is pressed in wrong way of load, brinelling takes place. So, when miniature ball bearing is sealed, no load must be applied on it. 

    If miniature ball bearing is connected with wrong contaminated shaft and housing, then it causes misalignment. If fits is pressed a lot with shaft damage occurs. 

    23. Which Type of Cage Designs Can Be Used in Miniature Bearing? 

    The miniature bearings can be protected by using various types of special cages. These cages help to keep the balance between the balls so that they may not result in friction and collapse. 

    Cages Used in Miniature Bearings

    • Ribbon Cages

    Ribbon cage is grounded and molded steel components. Rolling elements are held in steel parts and the loop of any one steel part is bent over the other. 

    This type of cage is mostly used in larger bearings. 

    • Crown Cages

    Crown cage is used in smaller miniature bearings. The contact area between the internal and external diameter is very small. These cages are also used in thin miniature bearings.

    • Plastic Cages

    Plastic cages are made of modeled and divided plastic components.

    This type of cage is used when high speed movement of rolling element is required. It is good at producing no vibration. This plastic cage is used in miniature ball bearings. It has a longer greasing life.

    Types of cages

    Types of Cages in Miniature Bearing

    24. What Is Miniature Bearing Life? 

    Bearing life

    Miniature bearing’s life (L10) is regarded as the time in which miniature bearings operate and fulfil their functions for which they are made of. 

    Life of a bearing is defined as the number of revolutions covered and number taken at a mentioned speed and pressure before the failure occurs such as fatigue life failure.

    Fatigue life is bearing revolution reaching 90% before error occurs. The remaining 10% depicts the fatigue. 

    Factors Effecting Bearing

    • Improper handling 
    • Contamination
    • Load
    • Speed
    • Lubrication quality
    • Heat
    • Fits

    Miniature bearings must be placed in some dry, clean and cool places which should be free of dirt, debris and vibrations. In miniature bearings, it is less expected that they will experience fatigue. 

    The bearing life of miniature bearing is determined by:

    • L10 (basic rating life)
    • Cr (active/basic radial load rating)
    • Pr (active equal radial load)

    25. What Is Miniature Load Rating and Fatigue Life of Miniature Bearing?

    Miniature Load Rating

    Miniature bearing load rating is the continuous or constant load which miniature bearing can undergo over one million revolutions covered by the internal ring. 

    The load rating applied is greater enough which can even result in deformation (plastic). 

    Where, C =FL

    The miniature bearing load rating is of different types

    • Basic active and dynamic radial load rating (Cr)
    • Dynamic and active equivalent radial load (Pr)
    • Basic static radial load rating (Cor) 
    • Static equivalent radial load (Por)

    Fatigue Life of Miniature Bearing

    Miniature bearing fatigue life is the life connected with 90 percent sureness. If the revolutions per minutes(RPMS) are constant, the miniature bearing life is given in hours. 

    26. What Is Miniature Bearing Internal Clearance? 

    The internal clearance of miniature bearings is referred as the number of movements which an internal ring covers while an external ring is constant and the number of rotation which the external ring covers when the internal ring is constant. 

    Internal Clearance Types

    • Radial clearance 
    • Axial clearance

    Radial clearance occurs when the rotation or movement done is in radial direction. 

    Axial clearance occurs when the rotation or movement done is in axial direction. This clearance relies on the raceways and radial clearance in its performance. When the radial clearance is static then the axial clearance becomes large like size of the ball and deflection increases. 

    An amount of load is also applied to measure internal clearance of miniature bearing. Internal clearance of miniature bearing is effected by fits, bearing life, amount of heat, rolling life and sound produced. 

    Internal clearance suffer a decrease when the miniature bearing is fixed between the rod and housing. 

    Types of Internal clearance

    Types of Internal Clearance

    27. What Is the Purpose of Lubrication in Miniature Bearing?

    Lubrication is vital thing in the maintenance of industrial machines. When the lubrication is not applied, the tiny rolling elements will experience a wear. 

    The vital role of the lubricant (grease) is to balance a space between the speedways and the tiny roller balls. Lubrication in miniature bearing gives a protective film from wear. 

    Lubrication in miniature bearing results in removal of heat generated and prevent from rust, condensation and foreign agents which causes contamination. 

    Lubrication reduces the amount of friction produced. It also protects the rolling contact area by providing shield over it through usage of oil film. 

    28. What Are the Lubricating Methods and Lubricants for Miniature Bearing?

    Lubrication is something which increases the fatigue life of miniature bearing. It has a greater impact on the working of miniature bearing. Miniature bearing or instrument bearing is lubricated once in a lifetime than that of other larger bearings. 

    Methods and Types of Lubricants

    • Grease Lubrication 

    Grease is a semi-solid lubricant. It is a compound of base oil and thickener. They are more viscous like honey than that of oil. Grease lubricants do not experience leakage. Grease is unable to add constantly. Grease has greater adhesive strength. 

    Grease reduces the friction and entry of foreign particles. 

    Grease is applied to miniature bearing by grease gun, custom hand filling as well as by using spray devices. 

    Grease is made of additives, various minerals and soaps such as lithium, sodium, calcium and aluminum. Filtered grease should be used in miniature bearing. The amount of grease used in miniature bearing must be less such as 10%. 

    • Oil Lubrication 

    Miniature bearings made of oil offer a less startup including high speed. Oil is less viscous and run out of the surfaces very quickly. Due to low adhesive quality it feels more of water than honey. Oil suffers leakage so there are chances of contamination or foreign agents. 

    Lubricating oil is a mixture of synthetic substances, vegetable or animal oil. Hydrocarbons are used as additives in lubrication oil. Oil is made of synthetic substances such as esters and silicone. 

    Lubrication of miniature bearing

    Lubrication of Miniature Bearing

    Methods of Miniature bearing Oil Lubrication 

    • Drip oil feed lubrication

    This method is applied on miniature bearing when the machines are running with low speed and carrying low load. This lubrication method is applied when lubrication is needed at regular intervals. The oil is given by the help of needle valve 

    • Splash oil feed lubrication

    This method of applying oil lubrication to miniature bearing is used for constantly demanding lubrication on pistons. The oil is splashed on the miniature bearing. This system has a oil scoop on the shaft. The bottom part of hoop is dipped in oil pool. The oil is brought to the miniature bearing raceways when the shaft moves. 

    • Force oil feed lubrication

    When the machines are running at faster speed then the possibility of greater friction is present. So, the forced oil lubricating method of miniature bearing is used. In this case forced oil is directed on the moving part. For example, gear boxes. 


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