tailieunhanh - Mechanical Engineers Reference Book 12 Part 11

Tham khảo tài liệu 'mechanical engineers reference book 12 part 11', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Power transmissions 10 19 Figure Multi-groove pulley cross section. PL pitch line OD outside diameter h groove depth from PL b distance between OD and PL a0 groove angle e centre-to-centre of grooves edge of pulley to centre of first groove g top width of groove dp pulley pitch diameter Ip pitch width of V-Belt Figure Narrow V-Belts better known as wedge belts have a narrower profile than classical V-Belts with a relative height of approximately . There is a more even distribution of the tension forces between the reinforcing cords and thereby a higher power rating compared to classical V-Belts of the same top width The pulley surfaces and especially the groove sidewalls should be machined such that the surface finish is a maximum of 3-2 when determined by the method described in BS 1134. Pulleys must be balanced either statically or dynamically depending on the rim speed and ratio of face width to diameter. BS 3790 contains comprehensive balancing information. In general for all pulleys operating below 10 m s rim speed and for pulleys with face widths half or less of the diameter operating below 20 m s rim speed static balancing is adequate. Pulleys employing split-taper bushings are most convenient for installation and removal in that they avoid the need for interference fits keys etc. A Taper-Lock pulley manufactured by J. H. Fenner Co. Ltd is shown in Figure . Figure A Fenner Taper-Lock bushing for securing a large pulley to a shaft Table Bell section Zp mm b mm h mm e mm f mm a g mm mm Zp Y 32 63 36 63 Z-SPZ 34 80 38 80 A-SPA 34 118 38 118 B-SPB 34 190 38 190 C-SPC 34 315 38 315 D 36 500 38 500 10 20 Power units and transmission Selection of belt drives BS 3790 1981 contains all the information necessary to design a drive power .