斯凯孚高温轴承应用

SKF solutions for extreme temperature applications

The Power of Knowledge Engineering

even under extreme operating conditions

Equipment that must operate in extremely clean environ-ments or environments with very high or very low tempera-tures can be difficult and expensive to lubricate effectively. Inadequate lubrication limits bearing service life – and with it, machine performance and productivity.

While alternative, extreme lubrication solutions exist, many cause additional problems. Lubricants used to reduce friction can melt or evaporate at extremely high tempera-tures. This not only creates e nvironmental issues, but increases the costs associated with the purchase and dispos-al of grease as well as the time and manpower to continually relubricate the bearings. At very low temperatures,

l ubricants can be ineffective and a considerable amount

of friction can be generated in the bearing.In food, pharmaceutical and medical applications, cleanliness concerns and requirements restrict or prevent the use of grease or oil, requiring alternatives that are often very expensive. Even when l ubricants are used, frequent wash downs can result in lubricant washout, which introduces moisture into the bearing, causing it to fail prematurely.

Match the solution to your extreme

a pplication

SKF has engineered a range of bearing and lubricant solu-tions designed specifically to address the challenges of extreme operating conditions. Combining SKF’s expertise in advanced materials, bearing design, machine reliability and application know-how, these solutions can help you break through limitations – and achieve new possibilities in ma-chine performance, bearing service life, productivity and cost control.

SKF solid lubricant solutions – a dry alter

In some applications, the best lubricant is not petroleum based. These include extremely high temperature applications that cause lubricants to melt or evaporate and low temperature applications where grease becomes ineffective. Applications include roll-out tables and reheat furnaces in steel mills and kilns and dryers used to manufacture building materials. For these challenging environ-ments, SKF offers a dry alternative: a solid, graphite-based lubricant compound (designation suffix VA210) and a self-sacri-ficing graphite cage (designation suffix VA228).

A lubricant and seal in one

SKF VA210 is a graphite-based lubricant compound that is packed into the free space of a bearing and heated until it solidifies. Because the compound takes up the entire free space in the bearing, it protects the rolling elements and raceways from damage caused by contaminants. In effect, it acts as two products

in one: a lubricant and a seal.

For applications where corrosion

resistance is important, the

graphite-based lubricant can be

impregnated with a polymer

(VA2101). The polymer

improves corrosion

resistance and speed

capability of the

bearing. Outstanding performance

Bearings packed with the SKF dry lubricant graphite compound p rovide exceptional extreme-temperature performance, including: Increased reliability

Because the graphite compound acts as both a seal and a lubri-cant, reliability is improved in applications where standard rubber seals cannot be used.

Higher speeds

Can accommodate speeds of up to 2 000 r/min. For higher speed a pplications, contact the SKF application engineering service. Reduced friction

The graphite compound operates with virtually zero frictional

m oment, to significantly reduce energy consumption and heat generation.

Maintenance-free

Bearings packed with the dry graphite compound require no lubrication-related maintenance.

High load carrying capacity

The graphite compound does not limit the radial load carrying

c apacity of the bearing. It does, however, have limite

d axial load c arrying capacity and can accommodat

e only very minor amounts o

f misalignment.

Environmentally friendly

Because the standard graphite compound is made from natural m aterials, it does not present a hazard to the environment. And b ecause it is a dry, non-petroleum based solid, there is no grease to purchase or dispose of, and no leakage.

native for extreme conditions

An extreme alternative: the SKF self-sacri fi cing cage

2Z/VA228 shielded ball bearings are an excellent dry lubricant alternative for applications where speeds are below 200 r/min and

temperatures range from –45 to +350 °C. These unique bearings are fitted with a coronet cage made of graphite. During operation, the cage releases minute amounts of graphite powder that lubricate the bearing. The shields on these bearings protect against the ingress of contaminants and guide the cage axially. T o further protect the

bearing from corrosion and enhance running properties, all

bearing surfaces are coated with manganese phosphate. Even at the upper temperature limits, the graphite cage will not release dangerous vapours.

The cost-effective solution

The 2Z/VA208 like the 2Z/VA228 (above), is a shielded ball bearing with a graphite cage. However, instead of a coronet cage, the 2Z/VA208 has a

segmented graphite cage to separate the balls and provide the necessary lubricant. These cost- e ffective bearings are

designed for applications where speeds do not exceed 100 r/min.

Non-dry solutions for demanding applications

Every extreme temperature application has its own unique

challenges. As a result, SKF has developed special variants of ball bearings that have been adapted to deliver excellent performance, based on the operating conditions of the application.

VA201 extends bearing service life

SKF extreme temperature open design ball bearings with a VA201 suffix can significantly extend bearing service life. Packed with a polyalkylene glycol/

graphite mixture, these bearings can be used in applications where speeds do not exceed 250 r/min and temperatures range from –40 to +250 °C. T o further

protect the bearing from corrosion and enhance running proper-ties, all bearing surfaces are coated with manganese phosphate, which also enhances adhesion of the lubricant to the metal. The VA201 is also available with shields (designation suffix 2Z/A201).

Y-bearing units

SKF extreme temperature bearings in the VA201, VA228, VA210 and VA2101 executions are available as Y-bearing units in the following configurations:

Y-bearing plummer (pillow) block units ? Y-bearing units with a square flange housing ? Y-bearing units with an oval flange housing

? Custom bearings

SKF has a long history of partnering with customers in the design of bearings for special applications. While our line of extreme temperature bearings is designed for the most common applica-tions, we can also design custom solutions for unique challenges or exceptionally demanding applications.

Outstanding performance, ultimate reliability

SKF extreme temperature bearing and lubrication solutions provide an optimum combination of benefits that make them the smart choice for trouble-free operation.

Extended service life

Designed to perform with a minimum of maintenance, SKF

extreme temperature bearings are engineered to provide extended service life. SKF is the only bearing manufacturer to use advanced graphite technology to eliminate the need for bearing relubrication in extreme temperature applications.

Wide range of operating temperatures

Special lubricants make it possible for some SKF bearings to

perform in temperatures as low as –45 °C and as high as +350 °C.

Double shields

SKF extreme temperature bearings can be fitted with a protec-tive shield on both sides to prevent ingress of solid

contaminants, and to hold the lubricant in place.

Dry alternatives

For applications where petroleum based lubricants cannot be used, and for extremely high

temperature applications, bearings incorporating SKF dry lubricant graphite compound or a self sacrificing cage provide excellent performance and long service life.

Environmentally friendly and safe

The materials used in SKF extreme temperature bearings are environmentally friendly. They are extremely safe provided the

maximum allowable operating temperature is not exceeded.

The Power of Knowledge Engineering

Drawing on ?ve areas of competence and application-speci?c expertise amassed over more than 100 years, SKF brings innova-tive solutions to OEMs and production facilities in every major industry worldwide. These ?ve competence areas include bearings and units, seals, lubrication systems, mechatronics (combining mechanics and electronics into intelligent systems), and a wide range of services, from 3-D computer modelling to advanced condition monitoring and reliability and asset management services. A global presence provides SKF customers uniform quality standards and worldwide product availability.

Bearings and units Seals

Lubrication systems

Mechatronics Services

? SKF is a registered trademark of the SKF Group.

? SKF Group 2009

The contents of this publication are the copyright of the publisher and may not be reproduced (even extracts) unless prior written permission is granted. Every care has been taken to ensure the accuracy of the information contained in this publication but no liability can be accepted for any loss or damage whether direct, indirect or consequential arising out of the use of the information contained herein.Publication 6843 EN · February 2009

Printed in Sweden on environmentally friendly paper.