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The design of gear drives with variable transmission ratios
374
SYSTEMATIC:
Bearing Cages in resin pregnated cloth, PTFE, PTFCE, PTFCE modified with 9531 copper powder and silver and PTFCE modified with I o:/’ TiOs were tested. The tests demonstrated the possibility of using PTFCI? as a material for ball-bearing cages intended for operation at low temperature. It was also established that liquid nitrogen considerably increased the life 01 the bearing cages. Plain bearing Failures caused by Cavitation and some Preventive Measures. (in Czech) J. Honcu, Strojirrntstvi (Enginewing), 19 (3) (1969) 156-164; aa figs., I table, 35 refs. The author divides cavitation failures into several groups, analyses their causes and suggests some effective preventive measures. Examples of troubles with bearings of automotive compression ignition engines and rcmediai measures are given. Tensioning Limits of Bearing Screwed Joints and their Infhtence on the Deformation of the Bearing Bore. (in German) H. Peters and R. Straub, l,‘Dr-Z., III (5) (rgOg) 301-306; 9 figs., 8 refs. 1rnfavourable deformation of the bearing bores may occur during tensioning of the screw joints of bearing covers if the tensioning limits of the system arenot taken into account. Incorrect design may result in a jamming of the shaft in the bearing for too large a deformation, or an elimination of the force locking bearing shell fixing for too small a deformation. Especially in the Case of repeated tightening of the bearing screws, these deformations may Cause damage to the bearings if the various influencing parameters are not sufficiently considered. Experimental Investigation on Low-friction Momentum Bedding in Ball Bearings. I). Bouchain, VDI-Z., III (6) (1969) 395. Thesis abstract (in German). Optimisation of Hydrostatic Bearings for Minimum Power and Low-temperature Rise. J. P. O’Donaghue and W. B. Rowe, I&. L~h~icnfio~z, 27 (4) (1969) IOI-106; 6 figs., 3 refs. The authors emphasise the importance of designing bearings for minimum power dissipation and temperature rise. Criteria are given which enable a designer to derive optimum values of any parameter for his particular bearing application. Air-bearing Applications to Machine Tools and Measuring Instruments. H. I,. Wunsch. NEL Rep. ~VO. 390, 1969; 1~ figs., 16 refs. Available from National Engineering Laboratory, East Iiilbride, (Xasgow. wear, ‘3 (1969) 371-379
ABSTRACTS
OF
CURRENT
LITERATURE
The report attempts to illustrate the advan tages and limitations of air bearings in the machine-tool and measuring-instrument field by reference to actual industrial applications. It indicates likely future developments. Rolling Elements for Elevated Temperatures. D. Scott, NEL Rept. No. 392, 1969; 2 figs , 2 tables, 63 refs. Available from National Engineering Laboratory, East Kilbride, Glasgow. Elevated-temperature problems, the requircmcnts of materials and lubricants for their solution and work undertaken to investigate them are discussed. The report reviews the results of accelerated service simulation tests carried out in NEL with materials, surface treatments and lubricants potentially suitable for elevated-temperature rolling mechanisms and materials for unlubricated rolling contact. Microscopical and metallurgical investigation of failed specimens have been carried out to aid the study of failure mechanisms. 4.2.
Seals,
breaks,
gears
Correlation Equations of Wear. I. B. Tartakovskii, Russim Eng. J, , q8 (A) (1968) 8-11; 5 figs., L tables, 8 rcfs. (Translation of I’esfla. Mashinosfr., $8 (2) (1@3) 8-10 by P,E.li..X. of Gt. Britain.) The exponent&l equation of wear most accurately describes the process of the continuous increase in the wear rate as wear accumulates since this hypothesis forms the basis of the equation. Determining the Efficiency of Hypoid Gear Transmissions. G. ~2. Zhuravlcv, Rzlssinn Eng. J., &’ (2) (1968) 27-30; 3 figs., 3 refs. (Translation of l/e&z, il/fashim~t~~. , 48 (r ) (1968) 24-27 by P.E.R.A. of Ot. Britain.) Because of thelimitations of the usual formula further investigations mere carried out to find the mean sliding speed of the tooth surfaces termed the theoretical speerl. The Design of Gear Drives with Variable Transmission Ratios. K. S. Tarkhanov and L. P. Polosatov, RZ&YS& Eng. f., q8 (2) (x968) 31-34; 4 figs., I ref. (Translation of I’esta, Mnshin%tv., 48 (2) (196X) 27-31 by P.E.R.A. of Ct. Britain ) By calculating both the machine and working engagements it is possible to obtain a transmission efficiency meeting the requirements of strength, smoothness of operation and accuracy in the reproduction of the transmission ratio function. Research work should lead to the development of a number of new types of non-linear engagement includin:: racks and worms.
SYSTEMATIC:
Bearing Cages in resin pregnated cloth, PTFE, PTFCE, PTFCE modified with 9531 copper powder and silver and PTFCE modified with I o:/’ TiOs were tested. The tests demonstrated the possibility of using PTFCI? as a material for ball-bearing cages intended for operation at low temperature. It was also established that liquid nitrogen considerably increased the life 01 the bearing cages. Plain bearing Failures caused by Cavitation and some Preventive Measures. (in Czech) J. Honcu, Strojirrntstvi (Enginewing), 19 (3) (1969) 156-164; aa figs., I table, 35 refs. The author divides cavitation failures into several groups, analyses their causes and suggests some effective preventive measures. Examples of troubles with bearings of automotive compression ignition engines and rcmediai measures are given. Tensioning Limits of Bearing Screwed Joints and their Infhtence on the Deformation of the Bearing Bore. (in German) H. Peters and R. Straub, l,‘Dr-Z., III (5) (rgOg) 301-306; 9 figs., 8 refs. 1rnfavourable deformation of the bearing bores may occur during tensioning of the screw joints of bearing covers if the tensioning limits of the system arenot taken into account. Incorrect design may result in a jamming of the shaft in the bearing for too large a deformation, or an elimination of the force locking bearing shell fixing for too small a deformation. Especially in the Case of repeated tightening of the bearing screws, these deformations may Cause damage to the bearings if the various influencing parameters are not sufficiently considered. Experimental Investigation on Low-friction Momentum Bedding in Ball Bearings. I). Bouchain, VDI-Z., III (6) (1969) 395. Thesis abstract (in German). Optimisation of Hydrostatic Bearings for Minimum Power and Low-temperature Rise. J. P. O’Donaghue and W. B. Rowe, I&. L~h~icnfio~z, 27 (4) (1969) IOI-106; 6 figs., 3 refs. The authors emphasise the importance of designing bearings for minimum power dissipation and temperature rise. Criteria are given which enable a designer to derive optimum values of any parameter for his particular bearing application. Air-bearing Applications to Machine Tools and Measuring Instruments. H. I,. Wunsch. NEL Rep. ~VO. 390, 1969; 1~ figs., 16 refs. Available from National Engineering Laboratory, East Iiilbride, (Xasgow. wear, ‘3 (1969) 371-379
ABSTRACTS
OF
CURRENT
LITERATURE
The report attempts to illustrate the advan tages and limitations of air bearings in the machine-tool and measuring-instrument field by reference to actual industrial applications. It indicates likely future developments. Rolling Elements for Elevated Temperatures. D. Scott, NEL Rept. No. 392, 1969; 2 figs , 2 tables, 63 refs. Available from National Engineering Laboratory, East Kilbride, Glasgow. Elevated-temperature problems, the requircmcnts of materials and lubricants for their solution and work undertaken to investigate them are discussed. The report reviews the results of accelerated service simulation tests carried out in NEL with materials, surface treatments and lubricants potentially suitable for elevated-temperature rolling mechanisms and materials for unlubricated rolling contact. Microscopical and metallurgical investigation of failed specimens have been carried out to aid the study of failure mechanisms. 4.2.
Seals,
breaks,
gears
Correlation Equations of Wear. I. B. Tartakovskii, Russim Eng. J, , q8 (A) (1968) 8-11; 5 figs., L tables, 8 rcfs. (Translation of I’esfla. Mashinosfr., $8 (2) (1@3) 8-10 by P,E.li..X. of Gt. Britain.) The exponent&l equation of wear most accurately describes the process of the continuous increase in the wear rate as wear accumulates since this hypothesis forms the basis of the equation. Determining the Efficiency of Hypoid Gear Transmissions. G. ~2. Zhuravlcv, Rzlssinn Eng. J., &’ (2) (1968) 27-30; 3 figs., 3 refs. (Translation of l/e&z, il/fashim~t~~. , 48 (r ) (1968) 24-27 by P.E.R.A. of Ot. Britain.) Because of thelimitations of the usual formula further investigations mere carried out to find the mean sliding speed of the tooth surfaces termed the theoretical speerl. The Design of Gear Drives with Variable Transmission Ratios. K. S. Tarkhanov and L. P. Polosatov, RZ&YS& Eng. f., q8 (2) (x968) 31-34; 4 figs., I ref. (Translation of I’esta, Mnshin%tv., 48 (2) (196X) 27-31 by P.E.R.A. of Ct. Britain ) By calculating both the machine and working engagements it is possible to obtain a transmission efficiency meeting the requirements of strength, smoothness of operation and accuracy in the reproduction of the transmission ratio function. Research work should lead to the development of a number of new types of non-linear engagement includin:: racks and worms.