TM-9-2520-238-34 Direct Support for M113 Family Major Assemblies Download
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TM 9-2520-238-34 EQUIPMENT DESCRIPTION AND DATA — Continued 0002 00 DIFFERENTIAL RIGHT ANGLE GEARBOX. A splined propeller shaft couples the right angle gearbox, through a universal joint, to the carrier transmission output shaft. The splined shaft drives a matched spiral bevel gear set consisting of an input shaft gear and an output bevel gear bolted to a shouldered shaft. The input shaft gear is mounted in roller bearings, and the output bevel gear is mounted in ball bearings. The gears and bearings are adjusted by inserting or removing laminated shims. Steering Control Differential – Cutaway View STEERING UNIT ASSEMBLY. The steering unit assembly consists of two planetary gear trains, a common carrier, and two brake drums. Brake drum and control flange assemblies are rigidly coupled by a differential spider to form the carrier. Each of the two gear trains consists of a brake drum hub with integral gear, three external spur gears, three spur gearshafts, and steering spur gear. The external gears are fixed to their respective gearshafts and mesh with the integral hub which is bolted to the hub brake drum, and the gearshafts mesh with the steering gear. The gearshafts of both gear trains are positioned in groups of three, with the opposite gearshafts of each group meshing. The brake drums provide differential control. BRAKE SHOE ASSEMBLY. Each brake shoe assembly consists of three brake shoes with replaceable brake friction linings. Each set of brake shoes is held together by pins. They are of the contracting type arranged around the outside of the brake drums. When the right or left brake control lever is pulled, the torque action of the steering brake shaft contracts the diameter of the corresponding set of brake shoes and slows the rotation of that brake drum. When the brake control lever is released, a spring enlarges the diameter of the set of brake shoes allowing the brake drum to increase speed. OUTPUT SHAFT ASSEMBLY. The splines of the left or right output shaft mate with a left or right steering gear of the steering unit assembly. Each shaft is ball bearing mounted, with bearings pressed on the shaft. The left output support is fixed to the right angle gearbox. The right output support is fixed to the differential housing. 0002 00-7