FEROFORM PR Adavantages

Bearing Wear

Many factors affect the wear rates of individual bearings and it is difficult to predict lifetimes accurately. In applications where the above types of motion occur then wear rates will by very low providing "years" of operational use.

For all of the FEROFORM PR grade range an initial wear-in period occurs during the initial operating cycles. During this the synthetic fibers will be re-orientated where the high spots of the fabric seave are flattened out. This results in adjacent fires fires closing together and the bearing becoming smooth and shiny.

In intensive tests at 20N/mm² load and with over 2km of shaft movement the wear rate was measured at less than 0.2mm. This was with an amplitude of +/-30⁰, a cycle time of 19 secs and a stainless steel 316 shaft.

Coefficient of Friction

COF depends on type of movement, finish of mating surface, ambient temperature applied load and velocity. Typical figures for the FEROFORM PR grades range from 0.06-0.12 inducating that all of the products demonstrate extremely low friction properties.

Bacause all of the range have very low COF values stick slip will not occur,even where the shaft has not rotated for long periods of time.With FEROFORM PR 814 PTFE is transferred from the bearing onto the shaft providing aPTFE-PTFE contact which reduces COF further.

Increasing the bearing allowing the minimum size to be used to achieve the lowest COF,permitting efficient design of the bearing allowing the minimum size to be used to achieve the lowest COF.

Water Swell

All composite material show degree of swelling when completely submerged in water . Typically for FEROFORM PR grades this 0.1% across the bearing wall.

However where bearings are installed above the water line and in "humid" conditions than the swell across the wall thickness is typically 1/2 of the figure. If oil or grease are used to lubricate the bearing then swell across the wall thickness is typically 1/4 of this figure.

Coefficient of Thermal Expansion

FEROFORM PR grades have low CTE'S, Typically 100X10^-6/^oC and can be considered negligible at most operating temperatures. This results in a bearing that does not expand or contract significantly when in its housing.

Temperature Limit

Normally operating temperatures should be kept below 80^oC for FEROFORM PR grade bearings. Above this maximum temperature the bearing will need to be cooled, typically using water.

Increased wear may be incurred on the bearing surface as the temperature nears the maximum, reducing the performance of the bearing. Also (environmental+generated friction heat), the Pv Value is reduced to prevent the maximum oprating temperature of 80^oC beong exceeded.

Dirty Environments

FEROFORM PR grade bearings perform extremely well in dirty,and can tolerate ingress of solid material. It has to be accepted thet bearing life will be reduced in such conditions, but FEROFORM PR grade bearings perform signficantly better than other materials in such conditions. Scouring of the shaft sufface may occur where there is excessive contamination.

In salt and sea water environments FEROFORM PR grades retain there performance characteristics without losing structural integrity. They are also stable to most chemicals and contaminants. TENMAT Ltd. should be contacted for specific details.

Housing and Shaft Fits

FEROFORM PR grade bearings are generally installed using using a press,shrink or adhesive fit with the housing bore. The following tolerances can be used :

Housing Bore          H7
Shaft Tolerance      e7 low load,turning motion, axial motion
                           F7 medium load,oscillating motion,interrrupted turning
                           motion
                           h7 high load, impact loads, close running fit
Bearing Machining Min 0.08mm
Allowance