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TIMKEN Europe
Industrial Maintenance Manual

Industrial Maintenance Manual

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Introduction
This manual provides essential guidelines for the maintenance and handling of industrial bearings, emphasizing the importance of proper practices to prevent equipment failure and ensure safety.

Warnings and Cautions
Failure to adhere to maintenance instructions can lead to serious injury. Key warnings include avoiding spinning bearings with compressed air and not disassembling unitized bearings. Cautions include using mild steel bars for installation to prevent fragment release.

General Bearing Handling and Inspection
Proper handling and inspection are crucial for maintaining bearing performance and longevity. This section covers storage, removal, cleaning, and inspection processes applicable to all anti-friction bearings.

Bearing Storage
Bearings should be stored in a dry environment, away from direct contact with concrete floors to prevent rust. Protective coatings and packaging should remain intact until installation.

Removing Bearings from Equipment
Careful removal is necessary to avoid damage. Various tools, such as pullers, are recommended for different bearing types. Heating methods can assist in removal but should be used cautiously to avoid altering bearing properties.

Cleaning
Thorough cleaning is essential before inspection. Smaller bearings can be cleaned in wash tanks, while larger bearings may require specialized equipment. Proper drying and protection against rust post-cleaning are advised.

Inspection
Regular inspections during maintenance can prevent unexpected failures. Bearings should be checked for wear and damage, and the surrounding components should be inspected for compatibility and condition.

Installation
Bearings should remain in their packaging until installation to prevent contamination. Proper installation techniques are critical to ensure optimal performance and longevity.

Installation and Handling of Bearings
When installing new bearings, retain the manufacturer's lubricant and preservatives to protect against corrosion and fingerprints. Ensure a clean environment free from contaminants during installation. Plan the installation process by confirming the correct replacement bearing, necessary components, and tools, including lubricants if required. This preparation minimizes exposure to contamination and handling damage.

Precautions and Safety
Do not disassemble unitized bearings. Remove oil or rust inhibitors before heating parts to prevent fire hazards. Use mild steel bars for installation or removal to avoid high-speed fragment release. Check for burrs on ring seats and backing surfaces to prevent damage.

Handling Damaged Bearings
Bearings may become damaged due to improper storage or normal wear. Damaged bearings can often be repaired or refurbished. If a bearing is damaged prematurely, analyze the damage for insights.

Cleaning and Preparation
Thoroughly clean machine components near the installation site, focusing on mounting surfaces and housings. Ensure shafts are clean and free from nicks or burrs. Do not install bearings in damaged housings or on worn shafts. Repair ring seat damage with fitted sleeves or build up shafts with metal spray.

Heating Bearings
For tight fits, heat bearings or housings to expand them for easier installation. Use oil baths or induction heaters, avoiding temperatures above 120ºC (250ºF). Ensure even heating and avoid direct contact with heat sources. Calculate thermal growth using the formula: d x ΔT x α = Thermal Growth.

Temperature Guidelines
Follow specific temperature limits for heating or cooling bearings to prevent metallurgical changes. Avoid using torches for heating, as they can damage the bearing's structure.

Pressing on Bearings
Use an arbor press and mounting tube for smaller bearings. Inspect shafts and housings for damage and coat shafts with light oil to reduce pressing force. Apply pressure evenly to avoid damaging the bearing.

Adjusting Bearing Clearance
Bearing clearance, or preload, is crucial for accommodating thermal growth and misalignment. Tapered roller bearings allow for adjustable clearance. Other bearings have predefined clearances that can be slightly adjusted through interference fits.

Internal Clearances
Internal clearance settings, such as end play or preload, are critical for bearing performance. Tapered roller bearings offer flexibility in setting clearances for optimal performance. The relationship between fatigue life and bearing setting is illustrated in the manual.

Internal Clearance in Bearings
Overview: Internal clearance in bearings is crucial for absorbing the effects of press fitting and compensating for thermal expansion. It can be measured radially or axially, with radial measurement being more significant as per the American Bearing Manufacturers Association (ABMA).

Radial Internal Clearance (RIC): RIC is defined as the average outer ring raceway diameter minus the average inner ring raceway diameter minus twice the ball diameter. It is measured by moving the outer ring horizontally and taking multiple readings for accuracy.

Timken Prefix and Acceptance Limits: The document provides a detailed table of acceptance limits for various Timken bearing prefixes (H, R, P, J, JJ) across different bore diameters. These limits are crucial for ensuring proper fit and function in various applications.

End Play: End play is an alternative method for measuring internal clearance, used in special applications. It involves clamping one ring and applying a reversing load to measure movement parallel to the bearing axis.

Spherical Roller Bearings: For spherical roller bearings with tapered bores, a greater interference fit is required, reducing RIC. The document provides an example calculation for RIC reduction and emphasizes the importance of selecting the correct RIC to accommodate this reduction.

Factors Influencing RIC Reduction: RIC reduction is influenced by the expansion of inner rings on solid steel shafts and the reduction of RIC when outer rings are pressed into housings. Specific guidelines are provided for different materials and configurations.

Conclusion: Proper understanding and measurement of internal clearance are essential for the optimal performance of bearings. The document provides comprehensive guidelines and tables to assist in selecting and verifying the correct internal clearance for various bearing applications.

Inspection and Maintenance of Bearings
After cleaning, bearings should be inspected for fatigue spalling, heat discoloration, rust, damaged cages, and noticeable wear. Bearings with these issues should be replaced to avoid further damage. Inspect the outer and inner rings for nicks or burrs, and check the race for unusual wear or spalls. Use a metal probe to detect damage in smaller bearings. Larger bearings may require removal of inspection rollers for thorough examination. Seals should also be inspected and replaced if worn to prevent contamination.

Bearing Damage and Repair
Bearings can be damaged through improper handling or normal wear. Timken offers resources for analyzing bearing damage and provides repair services for large bearings, potentially saving up to 60% of replacement costs.

Installation Guidelines
Proper installation techniques are crucial. Do not remove bearings from packaging until ready to mount. Ensure housing and shaft are not damaged. Use tight fits for rotating rings and loose fits for stationary rings. Heating bearings can ease installation, but temperatures should not exceed specified limits to avoid altering bearing properties.

Bearing Fit and Adjustment
Proper fit is essential for performance. Inner rings should be pressed onto shafts with care to avoid misalignment. Outer rings require a tight fit, especially in aluminum or magnesium housings. Adjustments can be made for preload or end play depending on application requirements. Methods for measuring bearing settings include torque readings and dial indicators for axial movement.

Shim Pack and Spacer Length
Shim packs are used to adjust end play or preload. Fixtures can help determine the required shim amount. For applications needing a spacer between inner rings, a method for measuring spacer length is provided to ensure accurate bearing adjustment.

Conclusion
Timken tapered roller bearings allow for setting internal clearance during installation to optimize performance. Proper inspection, maintenance, and installation practices are critical for bearing longevity and efficiency.

Specifications and Limitations
The tables are applicable to solid or heavy-sectioned steel shafts and ferrous housings. They may not be suitable for light shafts, non-steel materials, nonferrous housings, or critical conditions such as high speed or unusual thermal conditions. Special fits may be required for assembly procedures or specific bearing settings.

Fitting Practices

Rotating Cones: Generally require an interference fit. Loose fits may be considered if proven effective through tests or experience.
Stationary Cones: Under high speed or heavy loads, interference fits are recommended. For moderate loads and speeds, a metal-to-metal or near-zero fit is suggested.
Rotating Cups: Should always use an interference fit.
Stationary Cups: Tight fits are recommended for non-adjustable applications to prevent deformation.

Precision Bearings
Precision class bearings should be mounted on similarly finished shafts and housings. Two-row and four-row bearings are preset to specific end play settings, which depend on the fitting practice and expected environment.

Tables and Measurements
The document includes tables for both metric and inch dimensions, detailing the cone bore and cup O.D. deviations and resultant fits for various classes of bearings. These tables provide specific tolerances and fit recommendations based on the application and load conditions.

Conclusion
Proper fitting practices are crucial for the performance and longevity of tapered roller bearings. For specific applications, especially in the rolling mill industry, consulting a Timken representative is advised to ensure optimal fitting practices.

Specifications:
The document provides detailed specifications for various types of bearings, including KRR, G-KRR, RA-RR, GRA-RR, and GYA-RR types. It lists shoulder diameters, housing bore dimensions, and fit tolerances for different bearing models. The specifications include both metric and imperial measurements, highlighting maximum and minimum dimensions for loose and tight fits.

Needle Roller Bearings:
Timken manufactures a wide range of needle roller bearings, including drawn cup needle roller bearings, heavy-duty needle roller bearings, and roller and cage assemblies. These bearings are designed to support radial loads and reduce friction. They are used in various applications such as automotive transmissions, agricultural equipment, and machine tools.

Storage and Handling:
Bearings should be stored in their original packaging to prevent contamination. New bearings do not require washing as the rust preventive is compatible with lubricants. Proper handling and installation techniques are crucial to maintain bearing integrity.

Bearings Without Inner Rings:
When the shaft serves as the inner raceway, it must have a hardness between 58 and 64 HRC. The surface finish should be wave-free with a roughness of Ra ≤ 0.2 µm. The document provides guidelines for case depth and shaft tolerances to ensure optimal bearing performance.

Bearings With Inner Rings:
Inner rings are used when the shaft cannot serve as a raceway. The document outlines the necessary strength, tolerance, and surface finish requirements for shafts used with inner rings.

Bearings With Outer Rings:
The housing must support the outer ring with minimal deflection. Specifications for housing strength, diameter variation, and surface finish are provided to ensure proper bearing function.

Mounting Techniques:
Drawn cup bearings require careful mounting due to their thin outer race. The document advises on proper installation methods to avoid distortion and ensure the bearing is correctly seated in the housing.

Installation of Bearings
Drawn cup bearings require careful installation to ensure proper alignment and avoid misalignment, which can reduce bearing life. An installation tool must be used to press the bearing into place, ensuring it is aligned with the housing bore. Open-end bearings should be installed with a positive stop on the press tool, and closed-end bearings can be piloted from below. Misalignment can cause unequal stress distribution along the rollers, reducing bearing life. Maximum slope values should not be exceeded to maintain calculated bearing life.

Maintenance Tools
Proper tools are essential for the installation, removal, and servicing of bearings. Timken offers various tools, including impact fitting tools, induction heaters, and pullers. Induction heaters provide a fast, controlled heating method without smoke or fumes, making them environmentally friendly. Hydraulic nuts and pullers facilitate the installation and removal of bearings, ensuring precise positioning and reducing the risk of damage.

Lubrication and Seals
Timken provides a range of lubricants designed for specific applications and environments. Proper lubrication is crucial for optimal equipment performance and bearing life. Lubricants prevent metal-to-metal contact, carry away heat, and protect against corrosion. The choice between oil and grease depends on the application, with each having distinct advantages. Oils are classified by viscosity, which is crucial for selecting the right lubricant based on bearing size, speed, temperature, and load.

Oil Advantages: Oil is preferred for high-speed applications and heat dissipation. It offers better lubrication at high speeds and temperatures, is easier to handle, and can be introduced in various ways such as drip-feed and circulating systems. However, it is harder to retain in bearings compared to grease.

Oil Delivery Systems: Common systems include oil baths, circulating systems, and oil-mist systems. Each system has specific applications and benefits, such as cooling, contaminant removal, and precise lubrication control.

Grease Lubrication: Grease is a semi-fluid product with a thickening agent that releases oil under load. It is easier to use than oil and requires periodic relubrication. Grease consistency is crucial and varies with temperature and mechanical action.

Grease Types and Characteristics: Different greases have varying properties, such as water resistance and temperature limits. Synthetic greases perform well across a wide temperature range. The NLGI classification system categorizes greases by consistency.

Temperature and Grease Life: Grease life decreases with temperature increases. The dropping point is critical, and greases should be selected with a dropping point significantly higher than the operating temperature.

Wet Conditions: Certain greases offer water resistance, but rust prevention requires proper inhibitors. Sodium soap greases can emulsify moisture, which may be beneficial or undesirable depending on the application.

Grease Selection and Application: The choice of grease depends on various factors, including application conditions and environmental factors. Proper application methods ensure effective lubrication and prevent issues like churning and lubricant starvation.

Prelubricated Bearings: These bearings are used where relubrication is difficult or hazardous. They are packed with stable greases for long life and specific applications.

Special Applications: Some applications require lubricants with special properties, such as chemical resistance or suitability for food handling. Timken provides guidance for these specialized needs.

Overview: This document is a comprehensive guide on lubrication and seals, specifically focusing on industrial bearing maintenance. It provides detailed information on various types of greases, their applications, and installation methods for seals.

Grease Types and Applications:

Timken Construction and Off-Highway Grease: Suitable for high sliding wear, dirty environments, and shock loading. Used in agriculture, mining, and construction equipment.
Timken Ball Bearing Electric Motor Grease: Designed for electric motors, alternators, and generators, handling heavy loads and wet conditions.
Timken Mill Grease: Ideal for extreme temperatures and severe loads, used in aluminum, paper, and steel mills.
Timken Synthetic Industrial Grease: Used in wind energy, pulp and paper machines, and marine applications, suitable for ultra-high speeds and extreme low temperatures.
Timken Ultra-High Speed Spindle Grease: For machine tools like grinding, drilling, and milling, handling moderate speeds and loads.
Timken Multi-Use Lithium Grease: General industrial applications, suitable for pins, bushings, and water pumps.

Specifications and Procedures:

Edge Relief: Both shaft and housing bore should have an edge chamfer to prevent defects.
Surface Finish: Specific roughness average (Ra) values are provided for shaft and housing bore surfaces to ensure proper seal installation.
Surface Hardness: Rockwell C-scale hardness requirements are specified for different seal models.

Seal Installation Methods:

Solid Seal Installation: Use proper installation tools or a wooden block and mallet, following a star pattern to avoid seal cocking.
Split Seal Installation: For ambient pressure applications, apply lubricant, split the seal, and ensure proper seating in the housing bore.
Isolator Installation: Inspect and lubricate o-rings, position the isolator correctly, and ensure proper seating without using tools.

Inspection and Maintenance:

Inspect sealing areas for leaks and ensure the sealing lip is not in a worn groove.
Post-installation, check for damage and ensure proper rotor function without flooding the isolator.

Additional Information: The document includes a lubrication selection guide and emphasizes the importance of seals in preventing contamination and ensuring effective lubrication.

Catalog excerpts

Industrial Bearing Maintenance Manual

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As WARNING Failure to observe the following warnings could create a risk of serious injury. Proper maintenance and handling practices are critical. Failure to follow installation instructions and to maintain proper lubrication can result in equipment failure. Never spin a bearing with compressed air. The rolling elements may be forcefully expelled. As CAUTION Failure to observe the following cautions could create a risk of injury. Do not attempt to disassemble unitized bearings. Remove oil or rust inhibitor from parts before heating to avoid fire or fumes. If a hammer and bar are used for installation...

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index a Timken - Where You Turn . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 b General bearing handling and inspection . . . . . . . . . . . . . . . 9 c internal Clearances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 d Shaft and housing requirements . . . . . . . . . . . . . . . . . . . . . . . . 31 e Shaft and housing tolerances abma Standard 7 . . . . . . . 37 f Tapered roller bearings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 g spherical roller bearings . . . . . . . . . . . . . . . . . . . . . . . . . . ....

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A Ti m ke -W he re Yo uT urn A n a Timken - Where You Turn

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TIMKEN - WHERE YOU TURN TIMKEN - WHERE YOU TURN Maintenance professionals around the world turn to Timken to help improve the performance and extend the life of their equip- ment. The information in this manual will help you follow proper in- dustrial maintenance practices to get the most out ofyour Timken products and the equipment in which they operate. You will find practical information describing how to install, adjust, lubricate and maintain all of the primary types of anti-friction bearings. We have also included additional information on maintenance tools ENGINEERING EXPERTISE Timken...

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al b be ar in gh an d lin g b General bearing handling and inspection General Bearing Handling And Inspection. . . . . . . . . . . . . . . . 11 . Bearing Storage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Removing Bearings From Equipment. . . . . . . . . . . . . . . . . . . . . . 12 Damaged Bearings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Lubrication. . . . . . . . . . . . . . . . . . . . . . . . . . . . . ....

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GENERAL BEARING HANDLING AND INSPECTION GENERAL BEARING Bearings are a vital component in major industrial equipment. Bearing problems can result in costly downtime, equipment dam- age and breakdowns. In addition, large industrial bearings repre- sent a significant capital investment. To attain reliable operation with high equipment performance and the lowest possible maintenance costs, it is essential to follow proper handling practices. This includes bearing storage, removal, cleaning, inspection and installation. The useful life of any bearing depends to a great extent on the care and maintenance...

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GENERAL BEARING HANDLING AND INSPECTION REMOVING BEARINGS FROM EQUIPMENT Each type of bearing design has a unique removal process. Regardless ofthe bearing type, the bearing must be removed with extreme care. If done incorrectly, you can damage the bearings, shafts or housings, requiring expensive repairs. For smaller bearings, there are a variety of pullers available to as- sist with bearing removal (Fig. 1). Information concerning special pullers or other removal devices can be obtained by contacting yourTimken representative. Fig. 1 Pullers for bearing removal For bearings installed with a...

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GENERAL BEARING HANDLING AND INSPECTION Fig. 4 Tanks are heated with electric coils and a pump is used to Fig. 3 Smaller bearings can be cleaned in a wash tank agitate the cleaning solution A WARNING Failure to observe the following warnings could create a risk of serious bodily harm. Proper maintenance and handling practices are critical. Failure to follow installation instructions and to maintain proper lubrication can result in equipment failure. Never spin a bearing with compressed air. The rolling elements Alkali cleaners, such as trisodium phosphate (TSP) mixed two or three ounces per gallon...

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GENERAL BEARING HANDLING AND INSPECTION between face of bearing bearing seat Fig. 5 It is important to check for burrs on the inner and outer ring seats and backing surfaces In addition to examining the bearing, a full inspection should in- clude the housing and shaft. Check for burrs or metal chips on the inner and outer ring seats and backing surfaces (Fig. 5). Burrs or chips can be removed by scraping or filing the damaged Inspect the shaft for proper size, roundness, burrs or other dam- age. A 12-point check of the shaft with a micrometer is suggest- ed (see page 33). If there is evidence...

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GENERAL BEARING HANDLING AND INSPECTION Fig. 6 Bearings can be heated in a pan or metal container filled Thoroughly clean all machine components near where the bearing will be installed, giving special attention to the mounting surfaces and housings. Housings should be cleaned, including blowing out the oil holes. If the equipment has blind holes where air is ineffec- tive, use a magnetic rod to remove metal chips that might have become lodged there during machining or maintenance. Shaft surfaces that will support and contact the bearing must be clean and free from nicks or burrs. Shaft shoulders...

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GENERAL BEARING HANDLING AND INSPECTION A CAUTION Failure to observe the following cautions could create a risk of injury. If the bearing is to be reused or returned for repair, do not use heat from a torch. Extreme heat from a torch can alter the bearing hardness and metallurgical structure, resulting in irreparable damage. Keep the bearings away from any localized high-heat source that may raise the bearingtemperaturetoo high, resulting in race hard- ness reduction. When heating bearings, be sure thatthey have enough time to ful- ly heat. Bearings typically require 20 to 30 minutes of soak...

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Industrial Maintenance Manual

Industrial Maintenance Manual

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