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Handbook Of Shaft Alignment Episode 1 Part 7

Tham khảo tài liệu 'handbook of shaft alignment episode 1 part 7', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 150 Shaft Alignment Handbook Third Edition FIGURE 4.8 Two different variations of gear couplings employing a spool piece. Disadvantages Requires lubrication Temperature limitation due to lubricant Difficult to calculate reaction forces and moments of turbomachinery rotors when using these couplings since the values for the coefficient of friction between the gear teeth vary considerably Centerline of Centerline of coupling hub with gear teeth sleeve Sleeve Gear tooth in pivoted position Gear tooth in tilted position FIGURE 4.9 Tilted and pivoted positions of the gear teeth in its sleeve. Flexible and Rigid Couplings 151 FIGURE 4.10 Gear tooth tracking pattern when subjected to misalignment conditions. 4.4.1.3 Metal Ribbon Couplings The metal ribbon coupling was introduced around 1919 by Bibby Co. Metal ribbon couplings consist of two hubs with axial grooves on the outer diameter of the hub where a continuous S-shaped grid meshes into the grooves. Misalignment and axial movement is achieved by flexing and sliding of the grid member in specially tapered hub teeth. Capacity up to 70 000 hp 100 rpm Maximum recommended speed to 6000 rpm Shaft bores to 20 in. Shaft spacing to 12 in. 152 Shaft Alignment Handbook Third Edition FIGURE 4.11 Metal ribbon type coupling. Courtesy of Falk Corporation Milwaukee WI. With permission. Special designs and considerations Grid fabricated from hardened high-strength steel. Close coupled hubs with removable spacer available. Advantages Easy to assemble and disassemble Long history of successful applications Torsionally soft Disadvantages Requires lubrication Temperature limited Speed limited 4.4.1.4 Universal Joint Couplings Perhaps the oldest flexible coupling in existence is the universal joint coupling. This coupling is also known as the Cardan or Hooke joint. The basic design consists of U-shaped shaft ends with a hole drilled through each U to accept a shaped cross. If one universal joint is used to connect two shafts together then