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the gears, the shaft to which they are keyed, and the supporting bearings and their housing, is replaced in position. Next the primary shaft member is put in, then the main shaft, and lastly the control members or shifting rods, until the gearbox is again as shown at A, and ready for bolting the top part in place.
The bearings used on the ends of the countershaft are often of the ball form, as shown at Fig. 333. Different methods of re
Fig. 333.—Conventional Methods of Retaining Ball Bearing Inner Races
on Sliding Gearset Countershaft.
taining the bearing in place are followed. That at A shows the use of a cap screw and clamping washer. At B a clamp nut is used to press the bearing inner race firmly against the shoulder on the shaft, while a lock nut keeps the clamp nut in place. A very simple method, and one that is entirely satisfactory, is shown at C. This consists of grooving the end of the shaft circumferentially and putting in a split ring, as shown at C. A common method of retaining the bearing inner race, and one recommended by ball bearing manufacturers, is shown at D. After the clamp nut is brought tightly against the face of the inner race a locking
wire is sprung around the nut and the point entered into a suitable drill hole which goes through the nut into the shaft as indicated. Another method having much in its favor is shown at E. In this a double row ball bearing is pressed against the shoulder by a
-GEAR SHIFT LEVER
HIGH AND INTERMEDIATE
F'ig. 334.—Diagram Showing Construction of National Three Speed
clamping nut which is separated from the bearing inner face by a locking washer of the form shown at E'. This has one projection on its inner periphery designed to engage a keyway cut in the shaft. The projection on the outer periphery is intended to be bent around one of the facets of the nut to hold it in place after it has been firmly seated against the locking washer and bearing inner race. Complete instructions for the maintenance and instal
lation of ball bearings and other anti-friction forms will be found in Chapter IX., which deals with rear axle construction.
The construction of a typical three speed forward and reverse selective transmission showing ball bearings and gear shift members is clearly shown at Fig. 334. This has the gear shaft and emergency brake levers carried by a suitable supporting casting forming part
Fig. 335.—Three Speed Sliding Gearset, Forming Part of Rear
Construction of Overland Automobiles.
of the gear case cover. In this gear box single row ball bearings are used at all points, except to support the telescoping end of the main shaft, which fits into the primary shaft and which rotates on a roller bearing. The primary shaft is supported by two single row bearings, the outer one being clamped so it holds the shaft steady while the inner and larger one has a floating outer race. When a ball bearing is clamped on both inner and outer races it
will take end thrust as well as radial load. A thrust is usually an endwise load, while a radial stress is a load applied from an up-and-down direction or sidewise. In this gearset the bearing inner races on the countershaft are pushed on tightly, these being a force fit on the shaft ends. No retention means are provided. The general construction of this gear box, which is that used on National cars, is so clearly shown that further description is unnecessary.
A three speed and reverse sliding gear set that forms part of the rear construction on Overland cars is clearly shown at Fig.
335. In this the primary shaft is carried on single and double row ball bearings, while the end of the main shaft to which the bevel driving pinion is secured is supported by a large double row hearing which is capable of taking end thrust and radial load in combination. The single row bearings on the end of the countershaft are subjected to radial loads only as the countershaft is kept from end movement by simple thrust members composed of a steel ball fitting into an adjustable screw plug. The gear shifting forks
are attached to the gear shifting shafts by means of taper pins which may be driven out to release the forks and permit of taking the transmission apart by removing pipe plugs in the side of the gear case which gives access to the retaining pins when the sliding gear members are in the neutral position as indicated.
In some gear boxes, especially those used on high-priced aut: