Automobile Production

Specialists in automobile industry deal with designing and manufacturing cars, so they should know that the production of the automobile comprises the following phases:

1) designing, 2) working out the technology of manufacturing processes, 3) laboratory tests, 4) road tests, 5) mass production.

It is important to know all these facts as before the automobile is put into mass production, it should be properly designed and the automobile must meet up-to-date requirements. What are these requirements?

The automobile must have high efficiency, long service life, driving safety, ease of maintenance and pleasant appearance.

In order to obtain all these qualities engineers should develop up-to-date (11) methods of designing cars, using new types of resistant to corrosion light materials.

Also it is important to know computer science because it is intended to shorten the time between designing and manufacturing. Computers offer quick and optimal solutions of problems.

Before the car is put into mass production all its units and mechanisms are subjected to tests (12), first in the plant’s laboratory, then the car undergoes a rigid quality control in road tests.

What qualities are required of the automobile? The modern automobile must be rapid in acceleration, must have smooth acting clutch (13), silent gearbox, dependable (14) brakes and steering system, as well as pleasant appearance. Also it must be comfortable and have all conveniences.

Bearings

A bearing is a mechanical device for decreasing friction in a machine in which a moving part bears-that is, slides or rolls on another part. Usually a bearing confines the motion of a part and prevents it from moving in any other way. The common bearings are found at the rigid supports of rotating shafts where friction is the greatest. That part of a shaft which rotates in a bearing is called a journal (1) and the outer portion is a sleeve (2).

Bearings were invented early in history; when the wheel was invented, it was mounted on an axle, and where the wheel and axle touched was a bearing. Such early bearings had surfaces of wood or leather lubricated with animal fat.

Modern bearings have been designated (3) as friction and antifriction bearings.

The first type comprises sleeve or journal bearings.; the second, ball and roller bearings (4). Neither type of bearings is completely frictionless, and both are highly efficient in reducing friction.

Bearing materials must have sufficient strength. They must be good conductors of heat, uniform in structure, resistant to abrasion, and have a low coefficient of friction when dry or slightly greasy. Steel, cast iron and various alloys are commonly used as bearing materials. Lubrication is necessary to reduce the frictional contact between the rolling members and the rotating cages (5), to help to dissipate the heat, otherwise the bearing may “seize”.

Gears

A gear is a toothed wheel or cylinder used to transmit rotary or reciprocating motion from one part of a machine to another. Two or more gears, transmitting motion from one shaft to another, constitute a gear train (6). Gearing (7) is a term used to describe systems of wheels or cylinders with meshing teeth (8).

The simplest gear is the spur gear (9), a wheel with teeth cut across its edge parallel to the axis. Spur gears transmit rotating motion between two shafts or other parts with parallel axes. In simple spur gearing, the driven shaft revolves in the opposite direction to the driving shaft. If rotation in the same direction is desired, an idler gear (10), is placed between the driving gear (11) and the driven gear. In any form of gearing the speed of the driven shaft depends on the number of teeth in each gear.

Bevel gears (12) are employed to transmit rotation between shafts that do not have parallel axes. These gears have cone-shaped bodies and straight teeth.

Helical gears (13) have teeth that are not parallel to the axis of the shaft, but are spiralled around the shaft in the form of a helix. Such gears are suitable for heavy loads because the gear teeth come together at an acute angle rather than (14) at 90˚ as in spur gearing.

Worm gearing is a variation of helical gearing. A worm gear (13) is a long, thin cylinder that has one or more continuous helical teeth that mesh with a helical, gear. Worm gears are used chiefly to transmit rotation, with a large reduction in speed, from one shaft to another at a 90˚ angle.