Tham khảo tài liệu 'sổ tay tiêu chuẩn thiết kế máy p37', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | CHAPTER 31 BELT DRIVES Wolfram Funk Prof. . Fachbereich Maschinenbau Fachgebiet Maschinenelemente und Getriebetechnik Universität der Bundeswehr Hamburg Hamburg Germany GENERAL FLAT-BELT DRIVE V-BELT DRIVE SYNCHRONOUS-BELT DRIVE OTHER BELT DRIVES COMPARISON OF BELT DRIVES NOMENCLATURE A Cross section b Width Cp Angular factor cB Service factor di Diameter of driving pulley d2 Diameter of driven pulley e Center distance E Modulus of elasticity F Force ft Bending frequency I Datum length of flexible connector M Torque n Speed P Power q Mass per length r Radius s Belt thickness t Pitch v Velocity z Number STANDARD HANDBOOK OF MACHINE DESIGN a Included angle P Angle of wrap e Elongation strain 1 Coefficient of friction r Efficiency z Slip p Specific mass 7 Stress Indices 1 Driving 2 Driven b Bending f Centrifugal max Maximum w Effective zul Allowable N Nominal GENERAL Flexible-connector drives are simple devices used to transmit torques and rotational motions from one to another or to several other shafts which would usually be parallel. Power is transmitted by a flexible element flexible connector placed on pulleys which are mounted on these shafts to reduce peripheral forces. The transmission ratios of torques and speeds at the driving and driven pulleys are determined by the ratio of pulley diameters. Peripheral forces may be transmitted by either frictional nonpositive or positive locking of the flexible connector on the pulleys. Because of their special characteristics flexible-connector drives have the following advantages and disadvantages as compared with other connector drives Advantages Small amount of installation work Small amount of maintenance High reliability High peripheral velocities Good adaptability to the individual application In some cases shock- and sound-absorbing In some cases with continuously variable speed variable-speed belt drive BELT DRIVES .
