Evrim Berk 030060161 6th Week

1-) Retaining (Snap) Ring

Previous One

A retaining ring, also known as a snap ring, is a fastener that snaps into a circumferential groove on a shaft or tube to form a shoulder. The assembly can be used to locate or restrict the movement of parts mounted on the shaft. Remaining rings are available for both external (shaft) and internal (bore) applications. They are made from either sheet metal or wire stock, heat treated for hardness and stiffness. To assemble a retaining ring, a special plier’s tool is used to elastically deform the ring so that it fits over the shaft (or into the bore) and then is release into the groove. (Mikell P. Groover; Fundamentals of Modern Manufacturing Materials, Processes, and Systems 3rd Edition; pg.775)

New One

Shoulders is an economical way of positioning parts on a shaft. But it usually requires shafts of very large diameter and it is a costly procedure. With retaining rings designers can allow for a smaller shaft diameter and reduce machining to cutting a narrow circular groove. Retaining rings work only when a small amount of axial ply is permissable. They provide a removable shoulder to locate, retain or lock accurately components on shaft or in bore and housings.

materials used: Retaining rings are usually made of spring steel and remain seated there in a deformed position.

Application: They can be used to replace cotter pins and washer set screws and collar or nut and shouldered shafts. Thus they effectively lower the cost of fastening and assembly.

Disadvantages: They require grooves for seating, which are stress raisers. Hence snap rings should be avoided in areas of high stress.

(Babu, Sridhar; Design of Machine Elements; pg.233)

2-) RWD (Rear Wheel Drive)

Previous One

A front engine, rear wheel drive (RWD) vehicle has the engine in front and the drive axle in the rear. The transmission is usually right behind the engine, and a drive shaft transfers power back to the rear axle.

(Auto body repair technology, James E. Duffy,Robert Scharff, p. 25)

New One

The traditional layout has the engine situated with its output shaft set longitudinally. In this arrangement the rear wheels act as the driving wheels and the front wheels swivel to allow the vehicle to be steered. In the past rear-wheel drive was a natural choice becuase of the difficulty of transmissing a drive to wheel that had to swivel for steering purposes.

Spacing out the main components in this layout makes each unit accessible but a drawback is the intrusion of the transmission components into the passanger compartment. These create a large bulge in the region of the gearbox and a raised long bulge, called a tunnel, down the centre of the car floor for the accommodation of the propeller shaft. Using the rear wheels to propel the car utilizes the load transfer that takes place from the front to rear of the vehicle when the car is climbing a hill or accelerating.

(Hillier V.A.W. Fundamentals of Motor vehicle Technology,p. 7-8)