Monorail guidance systems must be lubricated. Technical, economic and ecological factors will determine whether oil or grease should be used and which lubrication method should be applied.

A significant factor in selecting the type of lubrication is the environmental conditions (contamination, etc.) acting on the guidance system. If extreme conditions are anticipated, it is recommended that Schaeffler Group External Sales is consulted in the design phase.

RUE..-E (-L-KT), KUSE, KUVS, KUE are supplied with a preservative. The preservative is compatible with oils and greases having a mineral oil base.

Series KUVE..-B (-KT) is supplied with initial grease lubrication.

Monorail guidance systems run exclusively under mixed friction conditions. Doped lubricants should therefore be used in preference (type P to DIN 51502).

Used lubricants should be disposed of by environmentally-friendly methods. The use of lubricants is governed by national regulations for environmental protection and occupational safety as well as guidance from the lubricant manufacturers. These specifications must be observed.

The advantage of oil lubrication is the flushing effect.

Preference should be given to the use of oils CLP or CGLP to DIN 51517 and HLP to DIN 51524.

At operating temperatures between +10 °C and +70 °C, the viscosity should lie between ISO-VG 68 and ISO-VG 220, see table.

For low temperatures, oils with lower viscosity must be used.

For highly dynamic applications, oils to ISO-VG 100 are recommended.

If it is possible to draw upon practical experience or guidelines from the oil manufacturer, oils must not be used until their behaviour in relation to plastics, elastomers and non-ferrous metals has been tested.

The compatibility of oils must always be checked.

This must always be checked under dynamic conditions and at operating temperature.

In case of doubt, the lubricant manufacturer must be consulted.

Lubricant oils with a mineral oil base of the same classification are miscible with each other. However, the viscosities should be within one ISO-VG class of each other.

The miscibility of synthetic oils must always be checked. In case of doubt, the lubricant manufacturer must be consulted.

Compatibility with process materials (e.g. cooling lubricants) must be checked.

The values in the tables, link to link, are guide values.

They are valid for the following conditions:

• operating duration 100%
• C₀/P = 8
• v = 0,8 m/s
• stroke 500 mm to 1000 mm
• independent of mounting positions, 0° to 90°.

Precise values can only be determined in practice. Adequate provision of lubricant is indicated by a visible, unbroken oil film at the profile of the wipers.

The minimum oil quantity Q_min is valid for initial operation or for resumed operation after machine standstill of more than 8 hours; for values see tables, link to link.

For initial operation, it is measured such that the oil ducts, rolling elements and raceways will be adequately provided with lubricant.

The oil impulse quantity Q_imp is valid if the linear guidance system is connected to a central lubrication system and the stroke ratio is less than 200; for stroke ratio see link, for oil impulse quantity values see tables, link to link.

Carriages with a minimal lubricant quantity metering unit (KIT.RWU..-510, KIT.RWU..-511, KIT.RWU..-H-510 and KIT.RWU..-H-511) have integrated piston distributors. These supply a metered quantity of 0,12 cm³ per lubrication impulse to the carriages RWU. A separate piston distributor cannot be used with these guidance systems.

The lubricant quantities are valid for all mounting positions.

If heavy contamination is present, it may be necessary to increase the oil relubrication quantity.

The oil quantity for the damping carriage RUDS is dependent on the size of the recirculating roller guidance system RUE..-E (-L-KT).

The lubrication impulses must be carried out in direct succession.

RUE..-E (-L-KT) with a minimal lubricant quantity metering unit has integral piston distributors. A separate piston distributor cannot be used with this combination.

The advantages of grease lubrication are as follows:

• little requirement for design work; it may be possible to dispense with a central lubrication system
• the possibility of long term lubrication
• the use of reservoir lubrication.

For flowable greases of classes NLGI 00 and NLGI 000, the guide values for oil lubrication according to tables, link to link, are valid.

For flowable greases of class NLGI 0, the data for the lubricant quantity and relubrication interval in the section apply.

In clean environmental conditions, the impulse quantity can in certain circumstances be reduced to approximately 20% of the oil impulse quantity given in the tables. If lubrication is carried out using flowable grease for linear recirculating roller bearing and guideway assembly RUE25-D, the design RUE25-D-FE must be selected.

For the minimal lubricant quantity metering unit, only flowable greases of classes NLGI 00 and NLGI 000 are permissible.

It is recommended that lithium soap or lithium complex soap greases with a mineral oil base and EP additives are used. The base oil viscosity is shown in the table.

It is recommended that lithium soap or lithium complex soap greases with a mineral oil base are used. The base oil viscosity is shown in the table.

For high loads, greases doped with EP additives are absolutely necessary.

Greases may be mixed if:

• they have the same base oil type
• they have matching thickener types
• they have similar base oil viscosities:
  the difference must be no more than one ISO-VG class
• they have the same consistency (NLGI class).

In case of doubt, please contact us.

Experience shows that INA linear guidance systems lubricated with greases having a mineral oil base can be stored for up to 3 years.

The following preconditions apply:

• closed storage room
• storage temperature between 0 °C and +40 °C
• relative humidity ＜ 65%
• protection against chemical agents (vapours, gases, fluids).

It is the user's responsibility to follow the advice given by the lubricant manufacturer.

If the linear guidance system is not lubricated by a central lubrication system, the carriage (KUVE-B (-KT) with initial greasing as standard) must be greased before fitting using the initial grease quantity – for guide values see tables, link and link.

Since it is not possible to calculate all the influencing factors, the precise grease operating life can only be determined under actual operating conditions. The approximation formula below, however, can be used to determine a guide value for many applications:

The grease operating life is restricted to a maximum of three years due to the ageing resistance of the grease.

• in the case of linear recirculating roller bearing and guideway assemblies RUE-D, RUE-E (-KT), to 18 000 h

• in the case of linear recirculating ball bearing and guideway assemblies KUSE, KUVE-B (-KT), KUE, to 30 000 h.

The basic lubrication interval t_f is valid under the following conditions, Figure 2:

• a bearing temperature of ＜ +70 °C
• a load ratio C₀/P = 20
• no disruptive environmental influences
• a stroke ratio between 10 and 50, link.

The speed parameter is defined as follows:

The correction factor K_P takes account of the strain on the grease at a load ratio of C₀/P ＜ 20, Figure 3.

The factors are only valid for high quality lithium soap greases.

The correction factor K_W takes account of the displacement distance to be lubricated, Figure 4. It is dependent on the stroke ratio.

If the stroke ratio is ＜ 10 or ＞ 50, the grease operating life is reduced due to the risk of fretting corrosion or the loss of grease.

The stroke ratio is calculated as follows:

If the stroke is very short, the grease operating life may be shorter than the calculated value. In this case, special greases are recommended – please contact us.

The correction factor K_U takes account of shaking forces, vibrations (a cause of fretting corrosion) and shocks, see table.

These influences place an additional strain on the grease.

If cooling lubricant or moisture come into contact with the rolling element system, calculation is not possible.

If the guide value for the grease operating life t_fG is less than the required operating duration of the linear unit, relubrication must be carried out.

Relubrication must be carried out at a time when the old grease can still be forced out of the carriage by the new grease.

A guide value for the relubrication interval for most applications is:

The grease used for relubrication should be the same as that used for initial greasing; if different greases are to be used, the miscibility and compatibility of the greases must first be checked, see link.

The relubrication quantity is approximately 50% of the initial grease quantity. Relubrication should preferably be carried out with several partial quantities instead of the complete quantity at a single point in time.

Relubrication should be carried out with the carriage still warm from operation and the carriage should be moved during relubrication. The minimum stroke is four times the saddle plate length; for saddle plate length, see dimension tables (L₁).

If lubrication is carried out by hand, the grease gun, lubrication nipple and the environment of the lubrication nipple must first be cleaned thoroughly.

If long term lubrication units KIT.RWU..-E-410, KIT.RWU..-E-430, KIT.KWVE..-B-400 and KIT.KWVE..-B-430 are to be used, please contact us.

At initial operation and relubrication, the coefficient of friction increases temporarily due to the fresh grease. After a short running‑in period, however, the coefficient of friction returns to its original lower value.

The friction behaviour is determined significantly by the characteristics of the grease used. The consistency and base oil viscosity serve as approximate guide values.