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comparatively low speed and where maximum bearing efficiency is not important.
Q. Name important parts of any anti-friction bearing.
A. The important parts of an anti-friction bearing of the roller form are shown at Fig. 236-B, while those of ball bearings of the radial and double row types are outlined at Figs.237 and 238. The
Steel principal parts are an
Shell inner race, a number of supporting antifriction or rolling Separator elements, a suitable cage or separator to contain them and an outer race to act as path for the rolls or balls.
Q. Why is the separator or cage necessary? A. A ball or roller
Balls bearing may be made of the full type, i. e. proportioned so that prac
Balls tically no space shall
Cone exist between the balls or rollers. This intro- Fig. 238.-Important Components of Double duces an undesirable
Row Ball Bearing. element of friction, due to the rubbing of one revolving member against its neighbor, so most anti-friction bearing designers provide a cage, container or separator, that is depended on to separate the rolls or balls from each other.
Q. What are separators made from?
A. The design of the separator and the function it is intended to perform determine the materials to be used in its construction. A cage or retainer that is depended on to carry the balls or rolls and not to actually keep them separated from each other may be made of stamped steel while those forms that are intended to separate and guide rolling members usually pocket them in an oil filled individual chamber for each member and are generally die cast of bronze or white metal.
Fig. 239.—Front Hub of Ford Model T Mounted on Cup and Cone
Type Ball Bearings.
Q. What other function besides separating the balls or rolls must the separator perform in a "take down" bearing?
A. In a bearing of the cup and cone or taper roller type the separator also acts as a retainer to prevent the rolling elements coming out of place if the bearing is taken apart.
Q. Are annular radial type ball and roller bearings adjustable for wear?
A. Annular ball bearings having vertical load lines and roller bearings having straight rolls are not adjustable for wear.
Q. How is the factor of deterioration made negligible in annular bearings?
A. Annular bearings of the non-adjustable type are very accurately constructed and are made of material having a high elastic limit and great strength. As there is but little friction between the highly finished, accurately machined and fitted parts of a well made annular bearing there will be practically no wear and if the bearing is not overloaded and is properly lubricated the factor of depreciation will be negligible.
Q. What advantages have "take-up” bearings over the straight radial type, and wherein are the latter superior to the former?
A. When cup and cone ball bearings as outlined in a front hub at Fig. 239 or tapered roller bearings as shown at Fig. 240 are used it is possible to take up any looseness existing between the parts by screwing up on an adjusting nut that will bring the cone or inner member closer to the outer member which effectively eliminates lost motion. Bearings of this type may be easily removed for inspection and can always be adjusted by an experienced person so they will turn with minimum friction and with absolutely no lost motion. When used in front hubs in the manner indicated the combination of the two bearings which have diverging load lines from the center produces a hub mounting capable of withstanding end thrust from either direction and support a radial load as well. Bearings of the straight radial type would not be suited for this application
Fig. 241.-Gearbox With Shafts Mounted on Roller Bearings.
unless supplemented by forms capable of taking end thrust. A disadvantage of some moment sometimes advanced against the adjustable form of anti-friction bearings is that these may be adjusted too tightly or not tight enough by an inexperienced mechanician or novice motorist and the bearings be subjected to shocks and stresses that they were not designed to withstand, the result would be rapid depreciation and considerable friction at a point where this should properly be eliminated. When using annular non-adjustable forms of bearings these are received from the specializing manufacturer as a perfectly adjusted, free running unit which cannot be varied because no provision is made for changing the adjustment provided by the manufacturer. The non-adjustable type is practically a “fool proof” bearing.
Q. Name parts of automobiles where radial loads only are present.
A. Radial loads are present only in certain portions of the engine and gearset of the average automobile. In most cars the
Fig. 242.-Three Speed Gearset Using Ball Bearings.
connecting rod and crankshaft bearings are not subjected to thrust and the countershaft and main shaft of the gearset, unless this is incorporated as part of the rear axle, are subjected to practically only radial stress. In the illustration at Fig. 241 the use of flexible roller bearings on the countershaft, subjected to practically only radial loads, is outlined, while in Fig. 242 the application of single row annular ball bearings in a similar capacity is shown. In this form of gearset which is intended for attachment directly to the rear axle the bevel drive pinion is attached to and revolves with the