Seals are used to retain lubricant and to exclude contaminants. To seal efficiently, a radial shaft seal must run against a smooth, round surface – the seal counterface on the shaft. If the counterface wears out, the seal will no longer be able to fulfill its function. Wear sleeves are used to repair worn out shaft. Information about wear sleeves made by SKF is given in this article.
Typically, the counterface becomes scored when a contaminant particle is caught under the seal lip and abrades a track as the shaft rotates. As this continues, the seal will allow more particles to pass or get stuck, and seal efficiency deteriorates, eventually leading to malfunction of the component that the seal is meant to protect. To rectify the situation, it is necessary to repair the shaft surface or replace the shaft since a simple seal replacement will not be sufficient and machine needs to be disassembled. However, there is an easy solution to this problem that allows the shaft to be repaired in position and does not require a different seal size. The solution is the SKF SPEEDI-SLEEVE.
SKF SPEEDI-SLEEVE
The SKF SPEEDI-SLEEVE is a thin walled sleeve having a high quality finish to provide an optimal counterface for a radial shaft seal. The sleeve is simply pushed in to position over the worn area providing a sealing surface that is as good as a new shaft.
Features and Size Range
The SKF SPEEDI-SLEEVE is a thin walled (0.28.mm thick) sleeve made of high quality stainless steel. The contact surface is wear resistant and machined to a fine finish. The sleeve has a removable flange to simplify the installation. The flange can be removed after the sleeve is set in position. They are available in standard size range to covers shaft diameters from 11.91 to 203.33 mm (0.472 to 8.0 in).
SKF SPEEDI-SLEEVE Gold is an enhanced version of the standard SKF SPEEDI-SLEEVE, offering improved resistance to abrasive wear. They are designed for applications where extended sealing system life is needed. In these sleeves a thin metallic film is applied to the base stainless steel which gives a gold colour and surface hardness to approximately 80 – 85 HRC. SKF SPEEDI-SLEEVE Gold is available from stock for selected common sizes.
A SKF SPEEDI-SLEEVE looks as shown below.
Installation Procedure
No special equipment is required since the installation tool is supplied with the sleeve. A mallet and a pair of pliers are all that is needed for the installation. Although installation is simple, it should be done carefully to achieve the best results. As the thin walled sleeve has an interference fit, any disturbances on the shaft surface may create a similar pattern on the sleeve surface and the seal will leak. In view of this sleeves should not be placed over ports, splines or keyways etc. Before installation clean the seal counter surface on the shaft. File down any burrs or rough spots and fill deep wear grooves, scratches or very rough surfaces with suitable powdered metal epoxy filler. The sleeve must be positioned on the shaft before the filler has hardened. Remove the installation flange if required.
Large Diameter Wear Sleeves
SKF recommends the use of large diameter wear sleeves (LDSLV) where no SKF SPEEDI-SLEEVE is available (for shaft sizes in the diameter range 211.15 to 1143.00 mm). There are two designs of SKF large diameter wear sleeves; type LDSLV3 with a flange and type LDSLV4 without a flange. Both types are made of high quality SAE 1008 carbon steel and chrome plated to enhance the wear and corrosion resistance. The sleeve outside diameter is specially ground to provide a precision counter surface for the seal. The wall thickness of the standard sleeves is 2.39 mm. SKF large diameter wear sleeves are designed for a heated slip-fit installation and must therefore be uniformly heated to approximately 180° C prior to their installation on the shaft
