Page:Popular Science Monthly Volume 92.djvu/938

 9^2^2

��Popular Science Monthly

��Automobile Bearings and How to Care for Them Properly

THE bearings of the automobile are, to many motorists, as a closed book, into which they have never ventured to peep — they have been content to

���The usual type of ball race with the ball holding ring and steel balls in place

let the garage man "turn the trick." In a way this may be a wise course, but, after all, it is more satisfactory for the motorist to learn and know his own car than to motor in a depend-on-someone-else man- ner. The bearings constitute one of the most important features of the motor car and for this reason, if he is thoroughly to know his machine, the motorist must give some attention to the bearings.

The bearings with which the modern automobile is equipped may be divided into three different classes — plain, roller and ball, the names themselves describing the types with considerable accuracy.

Plain bearings —The plain bearing con- sists of a cylinder which is open at both ends and split down the sides. Generally it is made of bronze and has a babbitt, a soft metal lining, this being situated im- mediately against the rotating shaft. The babbitt and its supporting metal are securely locked together, and as a rule there are grooves, running crosswise of the bearing or at an angle, cut in the babbitt to permit of even distribution of oil. These bearings are used as supports for the crankshaft of the engine and also for the lower ends of the connecting rods — where they connect with the crank- shaft.

There is also another type of plain bearing, consisting of a bronze cylinder, without the babbitt lining, these usually being called bronze bushings. These are

��found at the top of the connecting rods, in the clutch, on the brake pedals, etc., or any other place where there is little dan- ger of excessive heat being generated.

When the babbitted plain bearing be- comes worn, the result is generally a knock within the motor. When this oc- curs it may be remedied by removing a shim, a very thin piece of metal located between the two halves of the bearing, or filing away part of the metal where the two halves touch. A laminated shim is made consisting of many thin steel layers and by removing one or more of these the offending looseness or play may be taken up. This babbitt-lined bearing requires perfect lubrication, for if the bearing is permitted to run dry excessive heat is generated through friction and the soft metal is quickly melted, or burned out, this being denoted by a pounding in the motor. The burnt-out or worn bearing should be replaced or repaired at the earliest possible moment, otherwise a ruined engine may result.

Roller bearings — These are cylindrical in form and vary in length. Each con- sists of a series of steel rollers which form this cylinder, and is divided into two main divisions — straight roller and tapered roller. There are radial roller bearings and thrust roller bearings and combina- tions of the two. These are generally

���A roller bearing and its sleeve which is used on larger and longer shaft surfaces

used in the rear axle and rear wheels of the automobile. Tf one roller should be- come worn an entirely new bearing should be installed, for if all the rollers are not the same size the accuracy of the complete part cannot be maintained.

Ball bearing This consists of steel balls which revolve between two holders or races. This is the most flexible bearing

�� �