Figure 13-6.-Power flow through a four-speed transmission.The double-disk clutch (fig. 13-4) is basically thesame as the single-plate disk clutch except that anotherdriven disk and intermediate driving plate are added.MULTIPLE-DISK CLUTCHA multiple-disk clutch is one having more than threeplates or disks. Some have as many as 11 driving platesand 10 driven disks. Because the multiple-disk clutchhas a greater frictional area than a plate clutch, it issuitable as a steering clutch on crawler types of tractors.The multiple-disk clutch is sometimes used on heavytrucks. Its operation is very much like that of the plateclutch and has the same release mechanism. The facings,however, are usually attached to the driving plates ratherthan to the driven disks. That reduces the weight of thedriven disks and keeps them from spinning after theclutch is released.You may run into other types of friction clutchessuch as the lubricated plate clutch and the cone clutch.These types are seldom used on automatic equipment.However, fluid drives are largely replacing the frictionclutches in automobiles, light trucks, and some tractors.For information on fluid drives (automatic trans-missions), refer to Construction Mechanic 3 & 2,NAVPERS 10644G-1, chapter 11.TRANSMISSIONThe transmission is part of the power train. Itconsists of a metal case filled with gears (fig. 13-5). Itis usually located in the rear of the engine between theclutch housing and the propeller shaft, as shown infigure 13-1. The transmission transfers engine powerfrom the clutch shaft to the propeller shaft. It allows thedriver or operator to control the power and speed of thevehicle. The transmission shown in figure 13-5 and 13-6is a sliding gear transmission. Many late model truckshave either a constant mesh or synchromesh trans-mission (explained later). However, both transmissionshave the same principles of operation and the same gearratios.A review of chapter 6 of this book will help you tounderstand the transmissions and power transfermechanisms described in this chapter.13-5
Integrated Publishing, Inc. - A (SDVOSB) Service Disabled Veteran Owned Small Business