Page 340 - The Tribology Handbook

CIO Slide lubrication

EXPOSED SURFACE
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Slides are used where a linear motion is required between
two components. An inherent feature of this linear motion is
that parts of the working surfaces must be exposed during EXPOSED
operation. The selection of methods of slide lubrication SURFACE
must therefore consider not only the supply and retention of
lubricant, but also the protection of the working surfaces
\
from dirt contamination. EXWSED SURFACE
Figure 10.1 Slide movements exposes the working
surfaces to contamination

Table 10. 1 The lubricafion of slides in various applications

Application Function of lubricant Lubricant commonly used Remarks
Slides and linear bearings on To minimise the wear of precision Depends on the type of slide or Swarfmust be prevented from
machine tools surfaces. Toavoid any tendency linear bearing. See next Table getting between the sliding
to stick slip motion surfaces
Slides and linear bearings on To reduce friction and wear at the Greases and solid lubricants are The sliding contact area
packaging machines, textile moving surfaces without con- commonly used but air lubri- should be protected from
machines, mechanical taminating the material being cation may also be possible dirt by fitting scraper seals
handling devices handled at each end if possible

Crossheads on reciprocating To give low friction and wear by The same oil as that used for the Oil grooves on the stationary
engines and compressors maintaining an adequate film bearings surface are desirable to help
thickness to carry the impact to provide a full oil film to
loads carry the peak load

01 L OIL 01 L
LEVEL LEVEL LEVEL

Figure 10.2 Typical wick lubricator arrangement Figure 10.3 Typical roller lubricator arrangement
on a machine tool on a machine tool

Table 10.2 The lubrication of various types of linear bearings on machine tools
Type of linear bearing Suitable lubricant Method of applying the lubricant Remark5
Plain slide ways Cutting oil By splash from cutting area Only suitable in machine tool applications
using oil as a cutting fluid
Mineral oil By wick feed to grooves in the shorter Requires scraper seals at the ends of the
containing polar component moving component to exclude swarf
additives to reduce
boundary friction
By rollers in contact with the bottom Only suitable for horizontal slides
face ofthe upper slide member, and Requires scraper seals at the ends of the moving
contained in oil filled pockets in the component to exclude swarf
lower member
By oil mist Air exhaust keeps the working surfaces clear
of swarf
Grease By grease gun or cup, to grooves in Particularly suitable for vertical slides, with
thesurfaceoftheshortercomponent occasional slow movement
Hydro-static plain Air or any other con- Under high pressure via control Gives very low friction and no stick slip
slideways veniently available valves to shallow pockets in the combined with high location stiffness.
fluid surface of the shorter member Keeps working surfaces clear of swarf
Linear roller bearings Oil Lower race surface should be just Not possible in all configurations. Must be
covered in an oil bath protected from contamination
Grease Packed on assembly but with grease Must be protected from contamination
nipples for replenishment
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