Rolling bearings, rolling bearing parts and Arcanol rolling bearing greases are high quality goods and thus require careful handling.

The performance capability of modern rolling bearings lies at the boundaries of what is technically feasible. The materials, dimensional and geometrical tolerances, surface quality and lubrication have been optimised for maximum levels of function, which means that even slight deviations in functional areas, such as those caused by corrosion, can impair the performance capacity. In order to realise the full performance capability of rolling bearings, it is essential to match the anti-corrosion protection, packaging, storage and handling to each other.

The anti-corrosion protection and packaging are a constituent part of the bearing and are thus optimised so that they preserve all characteristics of the product at the same time as far as possible. In addition to protecting the surface against corrosion, this includes emergency running lubrication, friction, lubricant compatibility, noise behaviour, resistance to ageing and compatibility with rolling bearing components (cage and seal material).

As a basic prerequisite, parts must be stored in a closed storage area which cannot be affected by any aggressive media, such as exhaust gases from vehicles or gases, mist or aerosols of acids, lyes or salts. Direct sunlight should be avoided since, apart from the harmful effects of UV radiation, it can lead to wide temperature fluctuations in the packaging. The temperature should be constant and air humidity should be as low as possible. Jumps in temperature and increased humidity lead to condensation.

The following conditions must be fulfilled:

• frost-free storage, i.e. at a temperature ＞ +5 °C (to prevent formation of white frost, a limit of +2 °C is permissible for a maximum of 12 hours per day)
• maximum temperature +40 °C
  (to prevent excessive drainage of anti-corrosion oils)
• relative humidity ＜ 65%
  (if changes in temperature occur, a limit of 70 °C is permissible up to 12 hours per day).

The temperature and humidity must be continuously monitored. This can be carried out using a datalogger. The measurements must be taken at intervals of no more than 2 hours.

At least 2 measurement points must be selected: the highest point and the lowest point in the vicinity of an external wall at which the goods can be stored.

Rolling bearings should not be stored for longer than 3 years. This applies both to open and to greased bearings with sealing shields or washers. In particular, specifically greased rolling bearings should not be stored for too long, since the chemical-physical behaviour of greases may change during storage. Even if the minimum performance capacity remains, the safety reserves of the grease may have diminished.

In general, rolling bearings can be used even after their permissible storage period has been exceeded if the storage conditions during storage and transport were observed. If the conditions are not fulfilled, shorter storage periods must be anticipated. If the periods are exceeded, it is recommended that the bearing should be checked for corrosion, the condition of the anti-corrosion oil and the condition of the grease before it is used.

The information on storage of rolling bearings applies correspondingly to Arcanol rolling bearing greases. The precondition is that the Arcanol rolling bearing grease is stored in closed, completely filled original containers.

Rolling bearing greases are mixtures of oil, thickener and additives. Such mixtures of liquid and solid substances do not have unlimited stability. During storage, their chemical-physical characteristics may change and they should therefore be used up as soon as possible.

If the storage conditions are observed, Arcanol greases can be stored without loss of performance for 3 years. As in the case of rolling bearings, the permissible storage period should not be seen as a rigid limit.

If stored as prescribed, most greases can be used after 3 years, if allowance is made for small changes. If there is any doubt when using older greases, the random sample checking of chemical-physical characteristics is recommended in order to determine any changes in the grease. It is therefore not possible to state storage periods for containers that have been opened. If containers are to be stored after opening, the grease surface should always be brushed flat, the container should be sealed airtight and it should be stored such that the empty space is upwards. High temperatures should be avoided in all cases.

Perspiration leads to corrosion. Hands should be kept clean and dry and protective gloves worn if necessary. Bearings should only be removed from their original packaging immediately before assembly. If bearings are removed from multi-item packaging with dry preservation, the package must closed again immediately, since the protective vapour phase is only effective in closed packaging. Bearings should be oiled or greased immediately after unpacking.

The anti-corrosion agents in bearings with an oil-based preservative are compatible and miscible with oils and greases having a mineral oil base. Compatibility should be checked if synthetic lubricants or thickeners other than lithium or lithium complex soaps are used. If there is an incompatibility, the anti-corrosion oil should be washed out before greasing, especially in the case of lubricants with a PTFE/alkoxyfluoroether base and thickeners based on polycarbamide. Bearings should be washed out if the lubricant is changed or the bearings are contaminated. If in doubt, please contact the relevant lubricant manufacturer.

The following are suitable for degreasing and washing of rolling bearings:

• aqueous neutral, acidic or alkaline cleaning agents. Check the compatibility of alkaline agents with aluminium components before cleaning
• organic cleaning agents such as paraffin oil free from water and acid, petroleum ether (not petrol), spirit, dewatering fluids, freon 12 substitutes, cleaning agents containing chlorinated hydrocarbons.

Cleaning should be carried out using brushes, paint brushes or lint-free cloths. In the case of resinous oil or grease residues, precleaning by mechanical means followed by treatment with an aqueous, strongly alkaline cleaning agent is recommended.

Legal regulations relating to handling, environmental protection and health and safety at work must be observed. The specifications of the cleaning agent manufacturer must be observed.

Paraffin oil, petroleum ether, spirit and dewatering fluids are flammable, alkaline agents are corrosive. The use of chlorinated hydrocarbons is associated with the risk of fire, explosion and decomposition as well as with health hazards. These hazards and appropriate protective measures are described comprehensively in Code of Practice ZH1/425 of the Hauptverband der gewerblichen Berufsgenossenschaften (German Federation of Institutions for Statutory Accident Insurance and Prevention).

Rolling bearings must be dried and preservative applied immediately after cleaning (risk of corrosion).

Comprehensive information on fitting and dismantling is given in the publications WL 80 100, Mounting of Rolling Bearings and WL 80 250, Equipment and Services for the Mounting and Maintenance of Rolling Bearings.

For more extensive work, a fitting manual should be available that precisely describes all relevant work. The manual should also contain details on means of transport, fitting equipment, measurement tools, type and quantity of lubricant and a precise description of the fitting procedure.

The following guidelines must always be taken into account:

• The assembly area must be kept clean and free from dust.
• Protect bearings from dust, contaminants and moisture. Contaminants have a detrimental influence on the running and operating life of rolling bearings.
• Before fitting, familiarise yourself with the design by means of the final assembly drawing.
• Before fitting, check whether the bearing presented for fitting corresponds to the data in the drawing.
• Check the housing bore and shaft seat for dimensional and geometrical accuracy and cleanliness.
• Check that the shaft and housing bore have a lead chamfer of 10° to 15°.
• Wipe away any anti-corrosion agent from the seating and contact surfaces, wash anti-corrosion agent out of tapered bores.
• Lubricate the seats of the bearing rings lightly with oil or solid lubricant.
• Do not cool the bearings excessively. Moisture due to condensation can lead to corrosion in the bearings and bearing seats.
• After fitting, provide the rolling bearings with lubricant.
• Check the correct functioning of the bearing arrangement.

Avoid applying direct blows to the bearing rings with a hammer.

In non-separable bearings, apply the fitting forces to the ring with a tight fit, which should also be fitted first, Figure 1.

If the inner ring of a non-separable bearing will have a tight fit, press the bearing onto the shaft first, Figure 1. The bearing together with the shaft is then pushed into the housing (fit clearance).

In separable bearings fitting is easier; both rings can be fitted individually, Figure 2. Rotating the ring while fitting to give a screwdriver effect will help to avoid scraping marks.

Bearings up to d = 80 mm can be pressed onto the shaft while cold for normal tight fits, Figure 3. Mechanical or hydraulic presses can be used for this purpose.

If a press is not available, the bearings can be fitted by means of a hammer and a mounting sleeve.

In bearings with an angular adjustment facility, tilting of the outer ring is prevented by a mounting disc that is in contact with both bearing rings, Figure 4. In bearings with axially protruding cages or balls (e.g. some self-aligning ball bearings), the disc must have a turned recess, Figure 4 .

Bearings with a cylindrical bore should be heated before fitting if a tight fit on the shaft is intended and excessive effort is required for pressing by mechanical means. The temperature required for fitting is shown in Figure 5. The data are valid for maximum fit interference, a room temperature of +20 °C and a temperature safety margin of 30 K.

Induction heating devices are characterised by rapid, safe and clean operation. The devices are used mainly in volume fitting work.

Individual bearings can be heated on an electric heating plate­. A thermostatic controller must be always be used.

Thermostatically controlled hot air or heating cabinets are safe and clean. This method is mainly used for small and medium sized bearings. The heating times are relatively long.

With the exception of sealed, greased bearings and high precision bearings, rolling bearings of all sizes and types can be heated in an oil bath. A thermostatic controller is advisable (temperature +80 °C to +100 °C). In order that the bearings are heated uniformly, they should be laid on a grid or suspended in the oil bath.

With this method, please note the risk of accidents, environmental pollution by oil vapour, flammability of hot oil and risk of bearing contamination.

Bearings with a tapered bore are mounted either directly on the tapered shaft seat or by means of an adapter sleeve or withdrawal sleeve on a cylindrical shaft, Figure 6 , , .

Small bearings (up to approx. d = 80 mm) must be driven onto the tapered shaft seat or adapter sleeve using a locknut. The tight fit is achieved by pressing the inner ring on in an axial direction. The nut is tightened using, for example, a hook wrench. Small withdrawal sleeves can also be pressed into the gap between the shaft and inner ring bore using a locknut.

The reduction in radial internal clearance as a result of inner ring expansion is used as a means of checking the tight fit. In spherical roller bearings, the radial internal clearance (s_r) must be measured simultaneously over both rows of rollers, Figure 7. Alternatively, the axial displacement is measured.

Values for reduction in radial internal clearance and displacement in spherical roller bearings, see link.

For the measurement of radial internal clearance, aids such as feeler gauges FEELER-GAUGE-100 and FEELER-GAUGE-300 are suitable.

Even in the case of medium sized bearings, the forces required to tighten nuts are considerable. In such cases, fitting can be made easier by using locknuts with pressure screws, Figure 8 . This method is not suitable for spherical roller bearings of E1 design.

For the fitting of large bearings, a hydraulic device should be used to drive up the product or press in the sleeve, Figure 8 . Hydraulic nuts are available for all common threaded sleeves and shafts.

The hydraulic method gives considerable assistance in the fitting and particularly in the dismantling of bearings of approx. d = 160 mm and above.

For fitting, an oil with a viscosity of 75 mm²/s at +20 °C (nominal viscosity 32 mm²/s at +40 °C) is recommended.

Information on fitting and dismantling is given in the publications WL 80 100, Mounting of Rolling Bearings and WL 80 250, FAG Equipment and Services for the Mounting and Maintenance of Rolling Bearings.

Dismantling should be taken into consideration in the original design of the bearing position. If bearing rings are to be mounted with a tight fit, slots should be provided in the shaft or housing bore, for example, to allow removal of the rings.

If the bearing is to be reused, the following guidelines should be taken into consideration:

• do not use a concentrated or “hard” flame
• direct blows on the bearing rings should be avoided
• fitting forces must never be directed through the rolling elements
• carefully clean the bearings after dismantling.

If the bearings and adjacent parts are to be reused, the removal tool should be applied to the ring fitted with a tight fit. In non-separable bearings, the ring fitted with a drive fit is dismantled and the ring with a tight fit is then removed.

For the removal of small bearings, mechanical withdrawal devices, Figure 9 or hydraulic presses are suitable. Dismantling is made easier if there are slots on the shaft or housing so that the withdrawal tool can be applied to the bearing ring with a tight fit.

Special devices are available for cases where withdrawal slots are not present.

Induction heating devices are used to remove the shrink-fitted inner rings of cylindrical roller bearings, Figure 10.

Heating is achieved quickly and the rings are loosened easily without the transfer of substantial heat to the shaft.

Heating rings made from light metal with radial slots can be used to dismantle the inner rings of cylindrical roller bearings that have no ribs or only one rigid rib, Figure 11. The rings are heated on an electric heating plate to between +200 °C and +300 °C, pushed over the bearing ring to be removed and clamped in place using the grips. Once the press fit on the shaft has been eliminated, both rings are removed together.

The bearing ring must be separated from the heating ring immediately after removal in order to prevent overheating.

Where bearings are mounted directly on a tapered shaft seat or on an adapter sleeve, the locking effect of the shaft or adapter sleeve nut must be loosened first. The nut is then unscrewed by the amount of the drive-up distance. The inner ring is then driven off the sleeve or shaft, for example using a metal drift or impact block, Figure 12 , . An impact block avoids the risk of slipping.

Bearings located using withdrawal sleeves are dismantled using a withdrawal nut, Figure 12 .

Large bearings located using a withdrawal sleeve require considerable force. In this case, locknuts with additional pressure screws can be used, Figure 13 . A disc must be inserted between the inner ring and the pressure screws.

An easier and more economical method is the dismantling of withdrawal sleeves using hydraulic nuts, Figure 13 . The protruding withdrawal sleeve is supported by a heavy-section ring.

The dismantling of large bearings can be made easier by using the hydraulic method, Figure 13  and Figure 14. Oil is pressed between the fit surfaces. The adjacent parts can then moved in relation to each other by applying only slight force and without the risk of surface damage.

Tapered shafts must be provided with appropriate oil slots and feed holes. Oil injectors are sufficient to generate the pressure. The arrangement of oil ducts in the hydraulic method for dismantling of a spherical roller bearing from a tapered shaft seat is shown in Figure 14.

The withdrawal sleeve becomes loose abruptly. Leave the nut on the shaft.

Large adapter and withdrawal sleeves already have the appropriate slots and holes. In this case, a pump must be used to generate the oil pressure required.

For dismantling, the oils used should have a viscosity of approx. 150 mm²/s at +20 °C (nominal viscosity 46 mm²/s at +40 °C).

­Fretting corrosion can be dissolved by rust-dissolving additives in the oil.

If the bearings are not to be reused after dismantling, the products should be separated into their constituent parts. Grease, seals and plastic parts should be disposed of in accordance with the relevant waste product guidelines. Bearing rings and rolling elements should be sent for recycling.