7.11.10
Widianto
Normally every people who have a CAR or a Motorcycle will know with therminology ball bearing (In Indonesian Language is called “Bantalan”).
Ball bearings are at the heart of almost every product with a rotating shaft.
Anyway, do you know the manufacture of ball bearings?
I hope after I shared my knowledge on simple explanation below, you can increase the manufacturing knowledge of ball bearing. And please up date your knowledge with looking for the other Engineering literature to know more about manucfaturing process (on especially) and engineering (on generally).
Principles of Friction
For example, You have been asked to move a one ton, smoothly polished block of granite to another location. During your initial attempt to move the block, the two surfaces in contact (the base of the granite block and the ground) resist movement. This is called static friction. Trying harder, you exert greater force, enough so that the surfaces begin to slide against one another. Once in motion, the resisting force is from kinetic or sliding friction, rather than static friction. If that same block is now placed on five equally spaced rollers the force required to move the block is significantly decreased. Why? The rollers, in contact with both the surfaces of the roadway and block, still encounter friction; however, the rotating action of the rollers carries the block forward with less effort. The rollers eliminate the need to slide the block and have eliminated the resisting force of kinetic friction: the friction encountered is now classified as rolling friction. Rolling element bearings are designed to take advantage of this principle. They eliminate sliding friction and utilize the efficiencies of rolling friction to carry a load.
Rolling Element Bearings
Rolling element bearings consist of two circular steel rings and a set of rolling elements. One of the rings is much larger than the other—in fact, it is large enough for the other to fit well within its perimeter. This larger ring is referred to as the outer ring. The smaller of the two is the inner ring. A predetermined number of solid balls or rollers are formed into geometric shapes and placed at equal intervals in the open space between the two rings. These components are usually made of steel and are referred to as rolling elements. A cage, or retainer, is then used to maintain the intervals between the elements. This basic terminology will be used and expanded upon in the pages to come to describe the simple design and construction of a bearing.
Rolling Element Bearing Classifications The rolling elements are formed as standard geometric shapes which include :
1. Balls
2. Cylindrical Rollers
3. Needle Rollers
4. Tapered Rollers
5. Spherical Rollers
The geometric shape of these rolling elements are used to define the classification, or name, of each rolling element bearing type. Ball bearings use perfectly round balls as their rolling elements, cylindrical roller bearings use cylindrical rollers, etc.
Rolling Element Bearings and Tolerances
The precise operation of a rolling element bearing increases incrementally as each of the individual components approach "perfection" in its manufacture. The American Bearing Manufacturing Association (ABMA) has established two sets of tolerance classes that define the acceptable minimum and maximum manufacturing ranges for rolling element bearings. These are the ABEC (Annular Bearing Engineering Committee) tolerance classes for ball bearing and RBEC (Roller Bearing Engineering Committee) tolerance classes for roller bearings. The international bearing community also has an association to regulate international standards, the ISO or International Standards Organization. ISO and ABMA standards are identical with respect to these tolerances, although they use different class designations
Note : Bearings manufactured within tighter tolerance ranges provide greater accuracy of shaft rotation and contribute to higher speed capability.
Bearing Life
Bearing life refers to the amount of time any bearing will perform in a specified operation before failure. This is the life which 90% of identical bearings subjected to identical usage applications and environments will attain (or surpass) before bearing material fails from fatigue. Many factors have a profound affect on the actual life of the bearing. Some of these factors are :
1. Temperature
2. Lubrication
3. Improper care in mounting resulting in contamination, misalignment, deformation, etc.
As a result of these factors, an estimated 95% of all failures are classified as premature bearing failures.
Standard Ball Bearing Components
Bearings have a lot in common with Cars. A car’s basic design begins with a number of essential components for normal operation and can include additional components which may enhance performance. The same is true for bearings. The essential components of a ball bearing are defined as follows.
The Inner Ring (1)
This is the smaller of the two bearing rings and gets its name from the position it holds. It has a groove on its outside diameter to form a path for the balls. The surface of this path is precision finished to extremely tight tolerances and is honed to a very smooth, mirror-like surface finish. The inner ring is mounted on the shaft and is usually the rotating element.
The Outer Ring (2)
This is the larger of the two rings and, like its counterpart the inner ring, its name is derived from the position it holds. Conversely, there is a groove on its inside diameter to form a pathway for the balls. This surface also has the same high precision finish of the inner ring. The outer ring is normally placed into a housing and is usually held stationery.
The Balls (3)
These are the rolling elements that separate the inner and outer ring and permit the bearing to rotate with minimal friction. The ball radius is slightly smaller than the grooved ball track on the inner and outer rings. This allows the balls to contact the rings at a single point, appropriately called point contact. Ball dimensions are controlled to very tight tolerances. Ball roundness, size variations, and surface finish are very important attributes and are controlled to a micro inch level (1 micro inch = 1/1,000,000th, or one-millionth of an inch).
The Cage (Retainer) (4)
The main purpose of the cage is to separate the balls, maintaining an even and consistent spacing, to accurately guide the balls in the paths or raceways, during rotation, and to prevent the balls from falling out.
Lubrication
The lubricant is an integral part of a bearing’s standard components. However, the complexity of the subject merits more detailed examination and will be addressed in other training modules.
Bearing Loads
The rolling element bearing is subject to forces from gears, pulleys, or other components. These forces simultaneously act on the bearing from many different directions.
The direction in which force is exerted on the bearing helps identify the type of load on the bearing :
Radial loads are exerted on the bearing on a plane perpendicular (90°) to the shaft.
Axial loads or thrust loads, are exerted on the bearing on a plane parallel to the center of the shaft.
Combination loads exert both a radial and axial load on the bearing.
The illustration below shows a shaft mounted fan driven by a belt and powered by a motor. Two bearings support the shaft and are subjected to loads as follows :
Radial loads originate from the :
(A) Weight of shaft
(B) Weight of the pulley
(C) Tension of the belt
(D) Weight of the propeller
(E) Propeller rotation
Note : Radial loads exerted on the ends of the shaft, outside of the two bearings supporting the load ( for example : the belt tension, pulley weight and propeller weight), are compounded by a lever affect and are referred to as overhung loads.
Axial loads originate from the wind (E) induced by the propeller rotation.
Combination loads are the result of both radial load(s) and axial load(s) being combined and exerted on a single bearing.
Load Carrying Surfaces
As noted earlier, a bearing is designed to carry a load and reduce friction. The critical surfaces involved in supporting or carrying the load are :
The Balls (3)
Balls have been defined previously as one of the essential bearing components. They are subjected to the full brunt of the load carried by the bearing.
Cages (4)
Under normal conditions, cages carry very little load. However, when a bearing is not installed properly, is subjected to loads and speeds higher than recommended by the manufacturer, does not maintain proper lubrication, etc., the cage then may be subjected to loads far beyond what it is able to carry. These conditions can lead to premature cage failure.
The Raceways (5)
Raceways are the large, honed (highly polished), track surfaces on the inside of the outer ring (referred to as the outer raceway) and the outside of the inner ring (the inner raceway), that form a closed circle around the circumference of the ring. As the bearing rotates the rolling elements run on these surfaces.
Load Zone and Contact Points
When a bearing is supporting a radial load, the load is distributed through only a portion of the bearing—approximately one-third (1/3)—at any given time. This area supporting the load is called the bearing load zone.
Every point or surface where loads are supported by the bearing are load carrying contact points or surfaces. These include the outer Ring (O.D), inner Ring (I.D), the adjacent surfaces that form right angles to each other, raceways and rolling elements.
Manufacturing Process
Basically, Manufacturing Process for Ball bearing between one company with the others company does not have to same process.
Inner or Outer Ring
1. The bearing steel is machined (turned) or forged into rough cut, basic ring configurations;
2. Rings are machined to within rough tolerance specifications;
3. Rings are heat treated to increase the steel’s strength;
4. Ring faces receive the final grinding, removing any rough spots;
5. The ring O.D. and I.D. are finish ground to a smooth surface;
6. Raceways are also finish ground to an even surface;
7. The raceways are honed to a polished finish; and
8. The rings are then cleaned and readied for assembly.
Ball
1. The bearing steel wire is cold stamped (headed) into roughly shaped balls;
2. Balls are rough ground to remove the flashing (orbit) created during heading;
3. The balls are heat treated for strength; 4. Balls are rough ground again to remove coarser imperfections;
5. The balls are next finish ground; 6. The balls are lapped (a fine-polishing process); and
7. Finally, the balls are cleaned and readied for assembly.
The Stamped Steel Cage
1. Blanks, or donut shaped discs, are stamped out of strip steel;
2. The retainers are partially (rough) formed; 3. The retainers are next finish formed;
4. Retainers are then punched (if rivets are to be used);
5. Retainers go through a deburring process; and
6. The finished retainers are cleaned and readied for assembly
Ball Bearing Assembly
Before I start explain about Ball bearing Asssembly, for your information if you want to know process detail for "Ball" please visit on http://www.abbottball.com/about/production.asp
The bearing components will next go through the final assembly process. The assembled bearing is then cleaned, lubricated, noise tested, etc.
Ball bearings are at the heart of almost every product with a rotating shaft.
Anyway, do you know the manufacture of ball bearings?
I hope after I shared my knowledge on simple explanation below, you can increase the manufacturing knowledge of ball bearing. And please up date your knowledge with looking for the other Engineering literature to know more about manucfaturing process (on especially) and engineering (on generally).
Principles of Friction
For example, You have been asked to move a one ton, smoothly polished block of granite to another location. During your initial attempt to move the block, the two surfaces in contact (the base of the granite block and the ground) resist movement. This is called static friction. Trying harder, you exert greater force, enough so that the surfaces begin to slide against one another. Once in motion, the resisting force is from kinetic or sliding friction, rather than static friction. If that same block is now placed on five equally spaced rollers the force required to move the block is significantly decreased. Why? The rollers, in contact with both the surfaces of the roadway and block, still encounter friction; however, the rotating action of the rollers carries the block forward with less effort. The rollers eliminate the need to slide the block and have eliminated the resisting force of kinetic friction: the friction encountered is now classified as rolling friction. Rolling element bearings are designed to take advantage of this principle. They eliminate sliding friction and utilize the efficiencies of rolling friction to carry a load.
Rolling Element Bearings
Rolling element bearings consist of two circular steel rings and a set of rolling elements. One of the rings is much larger than the other—in fact, it is large enough for the other to fit well within its perimeter. This larger ring is referred to as the outer ring. The smaller of the two is the inner ring. A predetermined number of solid balls or rollers are formed into geometric shapes and placed at equal intervals in the open space between the two rings. These components are usually made of steel and are referred to as rolling elements. A cage, or retainer, is then used to maintain the intervals between the elements. This basic terminology will be used and expanded upon in the pages to come to describe the simple design and construction of a bearing.
Rolling Element Bearing Classifications The rolling elements are formed as standard geometric shapes which include :
1. Balls
2. Cylindrical Rollers
3. Needle Rollers
4. Tapered Rollers
5. Spherical Rollers
The geometric shape of these rolling elements are used to define the classification, or name, of each rolling element bearing type. Ball bearings use perfectly round balls as their rolling elements, cylindrical roller bearings use cylindrical rollers, etc.
Rolling Element Bearings and Tolerances
The precise operation of a rolling element bearing increases incrementally as each of the individual components approach "perfection" in its manufacture. The American Bearing Manufacturing Association (ABMA) has established two sets of tolerance classes that define the acceptable minimum and maximum manufacturing ranges for rolling element bearings. These are the ABEC (Annular Bearing Engineering Committee) tolerance classes for ball bearing and RBEC (Roller Bearing Engineering Committee) tolerance classes for roller bearings. The international bearing community also has an association to regulate international standards, the ISO or International Standards Organization. ISO and ABMA standards are identical with respect to these tolerances, although they use different class designations
Note : Bearings manufactured within tighter tolerance ranges provide greater accuracy of shaft rotation and contribute to higher speed capability.
Bearing Life
Bearing life refers to the amount of time any bearing will perform in a specified operation before failure. This is the life which 90% of identical bearings subjected to identical usage applications and environments will attain (or surpass) before bearing material fails from fatigue. Many factors have a profound affect on the actual life of the bearing. Some of these factors are :
1. Temperature
2. Lubrication
3. Improper care in mounting resulting in contamination, misalignment, deformation, etc.
As a result of these factors, an estimated 95% of all failures are classified as premature bearing failures.
Standard Ball Bearing Components
Bearings have a lot in common with Cars. A car’s basic design begins with a number of essential components for normal operation and can include additional components which may enhance performance. The same is true for bearings. The essential components of a ball bearing are defined as follows.
The Inner Ring (1) This is the smaller of the two bearing rings and gets its name from the position it holds. It has a groove on its outside diameter to form a path for the balls. The surface of this path is precision finished to extremely tight tolerances and is honed to a very smooth, mirror-like surface finish. The inner ring is mounted on the shaft and is usually the rotating element.
The Outer Ring (2)
This is the larger of the two rings and, like its counterpart the inner ring, its name is derived from the position it holds. Conversely, there is a groove on its inside diameter to form a pathway for the balls. This surface also has the same high precision finish of the inner ring. The outer ring is normally placed into a housing and is usually held stationery.
The Balls (3)
These are the rolling elements that separate the inner and outer ring and permit the bearing to rotate with minimal friction. The ball radius is slightly smaller than the grooved ball track on the inner and outer rings. This allows the balls to contact the rings at a single point, appropriately called point contact. Ball dimensions are controlled to very tight tolerances. Ball roundness, size variations, and surface finish are very important attributes and are controlled to a micro inch level (1 micro inch = 1/1,000,000th, or one-millionth of an inch).
The Cage (Retainer) (4)
The main purpose of the cage is to separate the balls, maintaining an even and consistent spacing, to accurately guide the balls in the paths or raceways, during rotation, and to prevent the balls from falling out.
Lubrication
The lubricant is an integral part of a bearing’s standard components. However, the complexity of the subject merits more detailed examination and will be addressed in other training modules.
Bearing Loads
The rolling element bearing is subject to forces from gears, pulleys, or other components. These forces simultaneously act on the bearing from many different directions.
The direction in which force is exerted on the bearing helps identify the type of load on the bearing :Radial loads are exerted on the bearing on a plane perpendicular (90°) to the shaft.
Axial loads or thrust loads, are exerted on the bearing on a plane parallel to the center of the shaft.
Combination loads exert both a radial and axial load on the bearing.
The illustration below shows a shaft mounted fan driven by a belt and powered by a motor. Two bearings support the shaft and are subjected to loads as follows :
Radial loads originate from the : (A) Weight of shaft
(B) Weight of the pulley
(C) Tension of the belt
(D) Weight of the propeller
(E) Propeller rotation
Note : Radial loads exerted on the ends of the shaft, outside of the two bearings supporting the load ( for example : the belt tension, pulley weight and propeller weight), are compounded by a lever affect and are referred to as overhung loads.
Axial loads originate from the wind (E) induced by the propeller rotation.
Combination loads are the result of both radial load(s) and axial load(s) being combined and exerted on a single bearing.
Load Carrying Surfaces
As noted earlier, a bearing is designed to carry a load and reduce friction. The critical surfaces involved in supporting or carrying the load are :
The Balls (3) Balls have been defined previously as one of the essential bearing components. They are subjected to the full brunt of the load carried by the bearing.
Cages (4)
Under normal conditions, cages carry very little load. However, when a bearing is not installed properly, is subjected to loads and speeds higher than recommended by the manufacturer, does not maintain proper lubrication, etc., the cage then may be subjected to loads far beyond what it is able to carry. These conditions can lead to premature cage failure.
The Raceways (5)
Raceways are the large, honed (highly polished), track surfaces on the inside of the outer ring (referred to as the outer raceway) and the outside of the inner ring (the inner raceway), that form a closed circle around the circumference of the ring. As the bearing rotates the rolling elements run on these surfaces.
Load Zone and Contact Points
When a bearing is supporting a radial load, the load is distributed through only a portion of the bearing—approximately one-third (1/3)—at any given time. This area supporting the load is called the bearing load zone.
Every point or surface where loads are supported by the bearing are load carrying contact points or surfaces. These include the outer Ring (O.D), inner Ring (I.D), the adjacent surfaces that form right angles to each other, raceways and rolling elements. Manufacturing Process
Basically, Manufacturing Process for Ball bearing between one company with the others company does not have to same process.
Inner or Outer Ring
1. The bearing steel is machined (turned) or forged into rough cut, basic ring configurations;
2. Rings are machined to within rough tolerance specifications;
3. Rings are heat treated to increase the steel’s strength;
4. Ring faces receive the final grinding, removing any rough spots;
5. The ring O.D. and I.D. are finish ground to a smooth surface;
6. Raceways are also finish ground to an even surface;
7. The raceways are honed to a polished finish; and
8. The rings are then cleaned and readied for assembly.
Ball1. The bearing steel wire is cold stamped (headed) into roughly shaped balls;
2. Balls are rough ground to remove the flashing (orbit) created during heading;
3. The balls are heat treated for strength; 4. Balls are rough ground again to remove coarser imperfections;
5. The balls are next finish ground; 6. The balls are lapped (a fine-polishing process); and
7. Finally, the balls are cleaned and readied for assembly.
The Stamped Steel Cage 1. Blanks, or donut shaped discs, are stamped out of strip steel;
2. The retainers are partially (rough) formed; 3. The retainers are next finish formed;
4. Retainers are then punched (if rivets are to be used);
5. Retainers go through a deburring process; and
6. The finished retainers are cleaned and readied for assembly
Ball Bearing Assembly Before I start explain about Ball bearing Asssembly, for your information if you want to know process detail for "Ball" please visit on http://www.abbottball.com/about/production.asp
The bearing components will next go through the final assembly process. The assembled bearing is then cleaned, lubricated, noise tested, etc.
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