Non-metallic bearing materials

M U R O , H., TSUSHIMA, N. Microstructural, microhardness and residual stress changes due to rolling contact. Wear, Vol 15, No 5 (May 1970) pp 309-330 Structural changes produced in various materials by roiling contact fatigue under various conditions are classified into 4 types (dark tint,dark needle, dark line and whRe band), depending upon test temperature, tempering resistance of the material, contact stress and loading cycle. Structural changes named dark tint,dark needle and dark line are observed in this order at different stages of the loading cycle in some cases. V a r i o u s k i n d s of s t r u c t u r a l c h a n g e s o b t a i n e d by d i f f e r e n t i n v e s t i g a t o r s a r e thought to be due to the v a r i e t y of t e s t condit i o n s , e s p e c i a l l y the t e m p e r a t u r e r i s e of the s p e c i m e n which is influenced not only by the contact s t r e s s but also by the r o t a t i o n a l s p e e d and c o n t a c t a r e a . (24 f i g u r e s , 13 t a b l e s ) ( T r i b o l o g y !970, a b s t r a c t 436)

M U R R A Y , S. F., P E T E R S O N , M. B. Non-metallic bearing materials. Mechanical Engineering, Vol 92, No 2 (Feb 1970) pp 43-48 Non-metallic bearing materials, such as plastics and ceramics, offer many unique advantages to the design engineer. For applications where bearings must operate w R h IRtle or no lubrication these materials are far superior to conventional metals. In this article the field is discussed in general terms with the emphasis on recent developments especially in the use of ceramics and hard metals. There is a guide to choice of non-metallic materials and some mention of newer applications such as reinforced plastic piston rings. (8 figures, 4 tables, 10 references) (Tribology 1970, abstract 437)

PERIN, Yu. I. et al S e l e c t i o n of optimum d i m e n s i o n s f o r r e i n f o r c i n g p l a s t i c gears. Russian Engineering Journal, translated from V e s t n i k M a s h i n o s t r o e n i y a , Vol 49, No 10 (1969) pp 56-58 P r o b l e m s c o n n e c t e d with m e t h o d s of r e i n f o r c i n g p l a s t i c s c o m p o n e n t s a r e e x a m i n e d taking K a p r o l a n g e a r w h e e l s a s a n e x a m p l e . The i n t e r f e r e n c e fit e m p l o y e d f o r r e i n f o r c i n g i s g i v e n a s a function of t h e r a t i o of the d i a m e t e r of the r e i n f o r c e r to the d i a m e t e r of the g e a r , and i t s o p t i m u m value is found. A study i s m a d e of the effect of v a r i o u s t e c h n o l o g i c a l f a c t o r s in the m a n u f a c t u r e of c a s t i n g s , and of the effect of r e l i e v i n g c a s t i n g s f o r l i g h t n e s s , on the a m o u n t of r e l a t i v e i n t e r f e r e n c e and s t r e s s e s due to r e i n f o r c i n g . (3 f i g u r e s , 4 r e f e r e n c e s ) ( T r i b o l o g y 1970, a b s t r a c t 438)

R I P P E L , R. C. D e s i g n i n g f l u i d - f i l m b e a r i n g s by c o m p u t e r . M e c h a n i c a l E n g i n e e r i n g , Vol 92, No 6 (Jun 1970) pp 30-41 The t e c h n i c a l l i t e r a t u r e devoted to fluid film l u b r i c a t i o n d u r i n g the p a s t 25 y e a r s h a s g r o w n exponentially, a p p r o x i m a t e l y doubled in q u a n t i t y e v e r y five y e a r s . The p u r p o s e of t h i s a r t i c l e is to point out s o m e of the m o r e p r e s s i n g n e e d s of fluid f i l m b e a r i n g d e s i g n e r s and a n a l y s t s and how t h e s e n e e d s c a n be s a t i s f i e d t h r o u g h the u s e of c o m p u t e r i z e d s o l u t i o n s . T h e v a r i o u s p o s s i b l e m o d e s of fluid f i l m l u b r i c a t i o n a r e i l l u s t r a t e d . The fluid m a y be a liquid ( i n c o m p r e s s i b l e a g a s ( c o m p r e s s i b l e ) and the b e a r i n g s u r f a c e c o n t o u r s v a r y f r o m flat to c y l i n d r i c a l , conical o r s p h e r i c a l . An a l m o s t infinite v a r i e t y of b e a r i n g s u r f a c e g e o m e t r i e s a r e p o s s i b l e . To i l l u s t r a t e the need f o r c o m p u t e r - a i d e d d e s i g n and a n a l y sis, the s c o p e of t h i s p a p e r is l i m i t e d to h y b r i d o p e r a t i n g ( h y d r o s t a t i c - h y d r o d y n a m i c ) fluid f i l m b e a r i n g s with i n c o m p r e s s i b l e fluids. (15 f i g u r e s , 3 r e f e r e n c e s ) ( T r i b o l o g y 1970, a b s t r a c t 439)

SCOTT, D. et al Composite materials for rolling bearing cages. Wear, Vol 15, No 4 (Apr 1970) pp 257-269 A r o l l i n g f o u r - b a l l t e s t , e l e c t r o n and optical m i c r o s c o p i c a l e x a m i n a t i o n s w e r e u s e d to a s s e s s v a r i o u s c o m p o s i t e r o l l i n g -

b e a r i n g cage m a t e r i a l s . All t e s t s u s e d En 31 s t e e l b a l l s . The r e s u l t s showed that the u s e of s p a c e r s of c o m p o s i t e m a t e r i a l s r e d u c e d w e a r of b a l l s by l u b r i c a n t t r a n s f e r . Ptfe b a s e d m a t e r i a l s with f i l l e r s such a s c a r b o n f i b r e and MoS 2 w e r e m o s t effective. F u t u r e work will u s e moulded i n s t e a d of m a c h i n e d c a g e s . (8 f i g u r e s , 3 t a b l e s , 22 r e f e r e n c e s ) (Tribology 1970, a b s t r a c t 440)

SK-URKA, J . C. E l a s t o h y d r o d y n a m i c l u b r i c a t i o n of r o l l e r b e a r i n g s . T r a n s l a t i o n s of the A m e r i c a n Society of M e c h a n i c a l E n g i n e e r s , J o u r n a l of L u b r i c a t i o n Technology, Vol 92, S e r i e s F, No 2 (Apr 1970) pp 281-291 R o l l e r b e a r i n g e n d u r a n c e t e s t s have b e e n r u n on g r o u p s of b e a r i n g s with L l o and L5o l i v e s e s t a b l i s h e d by Weibull a n a l y s i s . B e a r i n g r o l l e r path s u r f a c e finish, shaft speed, l u b r i c a n t v i s c o s i t y and l u b r i c a n t t e m p e r a t u r e w e r e v a r i e d . R e l e v a n t t a p e r e d r o l l e r and c y l i n d r i c a l r o l l e r b e a r i n g life data was s e l e c t e d f r o m p r i o r t e s t s f o r c o m p a r i s o n . Weibull p l o t s show the effect of the v a r i a b l e s on life and a g r a p h c o m p a r i n g the r a t i o of L l o t e s t life to the c a l c u l a t e d life and the r a t i o of e l a s t o h y d r o d y n a m i c l u b r i c a n t f i l m t h i c k n e s s to c o m p o s i t e r o l l i n g contact s u r f a c e f i n i s h i s given. T h e e m p i r i c a l equation to p r e d i c t the effect of v a r y i n g l u b r i c a n t and s u r f a c e f i n i s h c o n d i t i o n s on fatigue life i s given. (8 f i g u r e s , 7 t a b l e s , 13 r e f e r e n c e s ) (Tribology 1970, a b s t r a c t 441)

SNARE, B. How r e l i a b l e a r e b e a r i n g s ? Ball B e a r i n g J o u r n a l , No 162 (May 1970) pp 3-7 If a r o l l i n g b e a r i n g is c o r r e c t l y handled, fitted and l u b r i c a t e d the only c a u s e of d a m a g e will be fatigue. F a t i g u e life c a n be a n a l y z e d s t a t i s t i c a l l y but the r e d u c t i o n of life c a u s e d by o t h e r f a c t o r s c a n only be a s s e s s e d by s e r v i c e t r i a l s . The l e n g t h of t i m e that a b e a r i n g can be left in s e r v i c e a f t e r i t s n o m i n a l life h a s e x p i r e d is u n p r e d i c t a b l e and d e p e n d s m a i n l y on the u s e r , but b e a r i n g s have b e e n o p e r a t e d f o r 7× t h e i r n o m i n a l life. An e x a m p l e is g i v e n of the r e l i a b i l i t y of r o l l i n g b e a r i n g s in a p a p e r - m a k i n g m a c h i n e . (3 f i g u r e s , 3 t a b l e s , 3 r e f e r e n c e s ) {Tribology 1970, a b s t r a c t 442)

TAKEUCHI, E. The m e c h a n i s m of s l i d i n g w e a r of l u b r i c a t e d f l a k e g r a p h i t e c a s t i r o n . W e a r , Vol 15,No 3 (Mar 1970) pp 201-208 T e s t s with a p i n - o n - r i n g m a c h i n e w e r e done to find t h e effect of g r a p h i t e s p a c i n g and l u b r i c a n t oxidation on w e a r of c a s t i r o n . When the l u b r i c a n t was p a r t i a l l y oxidized it s u p p o r t e d oxidation of the sliding s u r f a c e aiding the p r o t e c t i v e effect of the oil film and c o u n t e r a c t i n g w e a r . If the l u b r i c a n t w a s e x c e s s i v e l y oxidized t h e r m a l e f f e c t s i n c r e a s e d the w e a r r a t e . The w e a r r e s i s t a n c e of the c a s t i r o n s i n c r e a s e d as the s p a c ings b e t w e e n the g r a p h i t e p a r t i c l e s d e c r e a s e d . (5 f i g u r e s , 2 t a b l e s , 10 r e f e r e n c e s ) (Tribology 1970, a b s t r a c t 443)

WILKENS, W., KRANZ, O. The f o r m a t i o n of g a s e s due to the s l i d i n g f r i c t i o n of T e f l o n on s t e e l in u l t r a h i g h v a c u u m . W e a r , Vol 15, No 4 (Apr 1970) pp 215-227 M a t e r i a l s which p r o d u c e g a s e s in v a c u u m which c o n d e n s e o r r e a c t c h e m i c a l l y on s e n s i t i v e s u r f a c e s (such a s e l e c t r i c a l c o n t a c t s , o p t i c a l s y s t e m s ) m u s t be e l i m i n a t e d in s p a c e c r a f t a p p l i c a t i o n s . The f o r m a t i o n of g a s e s by sliding f r i c t i o n of Teflon filled with 25°/° c a r b o n b l a c k was i n v e s t i g a t e d . By m a s s s p e c t r o m e t r y it was shown that all g a s e s p r o d u c e d could be a t t r i b u t e d to f r a g m e n t a t i o n of the Teflon m o l e c u l e . At l e a s t 60°/° of t h e s e g a s e s could c o n d e n s e on a c o p p e r s u r face cooled by liquid n i t r o g e n . It was concluded t h a t u s i n g Teflon a s a b e a r i n g m a t e r i a l n e a r s e n s i t i v e s u r f a c e s in s p a c e c r a f t was d a n g e r o u s . (7 f i g u r e s , 2 t a b l e s , 6 r e f e r e n c e s ) ( T r i b u l o g y 1970, a b s t r a c t 444) TRIBOLOGY N o v e m b e r 1970

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