2011

Report on Cylindrical Roller BearingsFAG bearings India Ltd.

Schaeffler group

Prepared by: Bhavin Chauhan

Semester 6th

Mechanical Engineering

Indian Institute of Technology

December 2011

PREFACE

Theoretical knowledge is just a part of complete knowledge. Complete knowledge about any subject cannot be attained by just knowing the theoretical background of it. Thought it plays an important role but it is not solely enough for proper understanding for any learner.

Theoretical knowledge in combination with practical knowledge gives the perfect and full understanding for the learner. Especially in the field of engineering, where students depends more on just theoretical knowledge, physical look of a machine and its working is also very important. A student cannot learn completely just by imagining the machines and working of the machine.

A good engineer is one, who excels in both the field. Considering this points, I took my training/intern-ship at FAG bearings India ltd. This report contains the details of various machines and operations carried out in the plant, which excels in the field of manufacturing of bearings.

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ACKNOWLEDGEMENT

I am greatly thankful to Mr. J. P. Nair and Mr. Rajshekhar for giving me this great opportunity.

I express my deep sense of gratitude to Mr. Khatavkar and other employees of FAG bearings for their excellent support throughout my intern-ship period.

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Fag India History and Milestones:

1962 - Incorporated as Precision Bearings India Limited.

1986 - The company name changed to FAG Precision Bearings Limited.

1993 - Became first Indian Bearing Company to achieve ISO 9001 certification.

1997 - EOU Project for Cylindrical roller bearings inaugurated.

1998 - Became first Indian Bearing company to achieve QS 9000 certification.

1999 - Change in name to FAG Bearings India Limited. The company achieved ISO 14001 certification.

2000 - Set up India's first production facilities to produce hub bearings.

2001 - Launched Joint Venture company FAG Roller Bearings Private Limited to manufacture taper roller bearings.

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Vision Statement:

“Our vision is the continuous development of FAG into a hi-tech company in precision and roller bearing technology, with international orientation and with convincing innovative capacity and earning power.”

Quality policy for FAG bearings:

“Our aim is to make all our products and services the delight of all consumers. We strive for excellence in all areas of operations while respecting environmental and social obligations. Every FAG India employee supports these missions by fulfilling the agreements made with all business associates.

The company is committed to providing all necessary resources to ensure attainment of these objectives.

The basis of FAG’s quality philosophy is the principle of continuous improvement through dedicated teamwork.

We emphasize our commitment to world-class quality and constantly endeavor to be the quality leader in our business and a profitable organization.”

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S.no Content Page no.

1 Introduction 6

2 Classification of Bearings 7

3 Cylindrical Roller Bearings 8

4 Parts of bearing and there types 9

5 Flow chart of different processes 13

6 Definition of some Mechanical processes

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7 Outer ring material flow processes 15

8 Inner ring material flow processes 17

9 Process description 18

INDEX

Bearing:

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A bearing is a device that is used in between two moving or rotating surfaces to facilitate smooth movement and to reduce friction. Bearings have a long history and even before the modern types of bearings came into existence, man used different objects that helped in transportation of large, heavy objects reducing friction. Bearings are classified depending upon their shapes and sizes and also according to motions they allow and their load bearing capacities. There are many types of bearings but the most common are roller bearings and ball bearings.

Bearings help moving parts rotate for long reducing friction. Most mechanical devices make use of one or the other type of bearings for their spinning parts. Though both roller and ball bearings serve the same basic purpose; their differences lie in their design and load bearing capacities.

Ball bearing:Ball bearings make use of hardened spherical balls that can handle both radial as well as thrust loads. They are made use where the load is relatively small. In the case of ball bearings, the load is transmitted from the outer race to the balls and then from the balls to the inner race. Because the bearings are spherical, there is very small area of contact with the load. Thus when the load is high, the balls may get deformed ruining the bearing.

Roller bearing:Roller bearings are used in applications where large load is to be borne, for example in conveyor belts where rollers must bear heavy radial loads. As the name implies, the roller is not a sphere but cylindrical in shape so that contact between the outer and inner race is not a point but a straight line. Thus there is a greater contact than ball bearings and the load is spread out over a larger area allowing roller bearings to bear a much heavier load than ball bearings.

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Basic difference between Roller Bearing and Ball Bearing

• Once we know the function and purpose of bearings, it is easy to make changes in shapes and designs for use in various circumstances. This is why ball bearings and roller bearings are used in different applications.

• In the case of ball bearings, the bearings are hardened spherical balls that greatly reduce the friction between moving parts but since the area of contact is a point only, they do not have a great capacity to bear loads.

• On the other hand in the case of roller bearings, the area of contact is a line rather than a point thus distributing the load over a larger area. They have a very high capacity to bear loads.

Ball bearings are classified into three types:

1) Deep groove ball bearings2) Four point ball bearings3) Self-aligning ball bearings

Roller bearings are classified into three types:

1) CRB – Cylindrical roller bearing2) SRB – Spherical roller bearing3) TRB – Taper roller bearing4) NRB – Needle roller bearing

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Cylindrical Roller Bearings

Cylindrical roller bearings, as the name suggests, are bearings that use cylindrical rollers as rolling elements. In these bearings, the rollers are in linear contact with the raceway. Cylindrical roller bearings have a large radial load capacity. Since the load is supported by the larger surface area offered by the cylindrical roller, they are suitable for handling heavy loads or for use at high speeds. Cylindrical roller bearings are typically used in machine tools, transmissions and wind turbines.

Fig. Cylindrical roller bearing

Parts of bearing:

1) Outer ring/race2) Inner ring/race3) Rolling elements (Roller/ball)4) Retainer

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The outer ring is the larger of the two rings and conversely has a groove on its inside diameter to form a pathway for the balls/rollers.

Types of outer ring:

1) NU type: Edges of the outer ring are rounded. In NU type, rollers are filled in outer ring.

Fig. Side view of NU type outer ring

2) N type: Outer ring have sharp edges. N type outer rings are only used with N type inner rings.

Fig. Side view of N type outer ring

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The inner ring is the smaller of the two rings and has a groove on its outside diameter to form a path for the balls or rollers. It is mounted to the shaft and is usually the rotating element.

Types of Inner ring:

1) NJ type: The inner ring is chamfered on one side and the other side consist of a collar.

Fig. Side view of NJ type inner ring

2) NUP type: One side of the ring is plain and other consist of a collar.

Fig. Side view of NUP type inner ring

3) N type: Both sides of ring consists of a collar. In N type, rollers are filled in inner ring.

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Fig. Side view of N type inner ring

4) NU type: Both sides are chamfered.

Fig. Side view of NU type inner ring

The rolling elements(Rollers) separate the inner and outer ring and permit the bearing to rotate smoothly with minimal friction. They carry the load and may be either balls, tapered rollers, spherical rollers or cylindrical rollers.

Fig. Cylindrical rollers fitted in outer ring

Retainer separates the balls or rollers, guides them in the pathways during rotation and prevents them from falling out. It may be made of steel, brass, bronze, etc. depending on the type or application of the bearing.

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Types of Retainer:

1) TVP 2: Made up of Plastic.2) JP-1: Made up of steel. Requires pressing for locking the roller.3) JP-3: Steel retainers having pockets and also requires pressing of rollers.4) M-1: Brass retainers. Consist two parts i.e. Bottom, which hold the rollers

and a cap on the top to lock. Locking is done by spot welding.5) M1-A: Brass retainers by change in dimensions.

Material flow of Cylindrical Roller bearing

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Lip Bore Grinding

OUTER RING MATERIAL FLOW

Lip Face Grinding

INNER RING MATERIAL FLOW

Basic mechanical processes/method involved in production of cylindrical roller bearing are:

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1) Grinding: Grinding is a finishing process used to improve surface finish, abrade hard materials, and tighten the tolerance on flat and cylindrical surfaces by removing a small amount of material. In grinding, an abrasive material rubs against the metal part and removes tiny pieces of material. The abrasive material is typically on the surface of a wheel or belt and abrades material in a way similar to sanding. On a microscopic scale, the chip formation in grinding is the same as that found in other machining processes. The abrasive action of grinding generates excessive heat so that flooding of the cutting area with fluid is necessary.

2) Honing: Honing is a similar to grinding. Honing is a final finishing operation conducted on a surface. Abrasive stones are used to remove minute amounts of material in order to tighten the tolerance on cylindricity. Honing is a surface finish operation, not a gross geometry-modifying operation. The limitation on geometric accuracy in grinding is overcome in honing because the honing stone follows a complex path.

3) Interchangeability: Interchangeability is a process in which different parts are made to such specifications that ensure that they are so nearly identical that they will fit into any device of the same type. One such part can freely replace another, without any custom fitting.

Outer Ring material flow processes:

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1) Lip Bore GrindingMachine used: ALS CNCTolerance: +80µm

Fig. Lip Bore grinding

2) Lip Track Grinding IMachine used: MIG 75 IBTolerance depends on the requirements of customer.

Fig. Lip track grinding

In Lip Track Grinding I, grinding takes place on only single side of outer ring.

3) Lip Track Grinding IIMachine used: MIG 75 IBGrinding of the other half of the outer ring takes place here.Figure will be same as that of Lip Track Grinding I.Tolerance depends on the requirements of customer.

4) Track GrindingMachine used: MIG 75G

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Tolerance depends on the roller size.

Fig. Track grinding of outer ring

5) HoningMachine used: HM 150G AR

Fig. Super-finishing of track of outer ring

Coolant used in Grinding processes is AWS 165 oil + Distilled Water.

Coolant used in Honing process is Oil.

Inner Ring Material Flow processes:

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1) Lip Face GrindingMachine used: AFE IISTolerance of Lip width: -20µm to -80µmTolerance of Track width: +20µm to -45µm

Fig. Lip Face Grinding

2) Track GrindingMachine used: MEG PUTolerance: ±15µm

Fig. Track Grinding

3) Bore GrindingMachine used: MIG 75 G

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Tolerance: -12µm

Fig. Bore Grinding

4) HoningMachine used: HM 75 G JR

Fig. Super-Finishing of track of Inner Ring

Measure and Match: Measure and Match is done by manual inspecting. The production of Inner and Outer rings is based on the method of Interchangeability.

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Roller Filling: Roller filling is done by machine. Some retainers require pressing for roller filling. An M-1 type retainer needs locking which is done by spot welding.

RC checking: Radial clearance checking is done here. Radial clearance depends on the requirements of Customers.

Laser Marking: Bearings are marked with the help of Laser. Company name, with bearing type, batch number etc. are marked on the bearing.

Washing: Bearings are washed to remove the remnants of the coolants used in grinding and honing.

Oiling: Oiling of bearings takes place to remove the moisture.

Noise check: In noise check, the device measures noise with an accelerometer contacting the outer race of the bearing while the inner race is rotated at 1800 RPM. Noise levels are separated into 3 bands, designated as follows:

High band             1,800 - 10,000 Hz Medium band        300 - 1,800 HzLow band              50 - 300 Hz

According to the type of bearing (material and noise grade), a different attenuation is used for each band. Standard testing procedure requires that bearings are washed clean of any lubricant and 2 drops of fresh MIL-L-6085A oil lubricant added prior to testing.

PDI: Pre dispatch Inspection is final manual inspection of the bearings. Irregularities on the surface of bearings and other defects are checked here.

Packing: Bearings are packed manually for final dispatch.

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