ALUMINIUM AND RUBBER

Auckland Star, Volume LX, Issue 232, 1 October 1929, Page 17

ALUMINIUM AND RUBBER

USE IN CAR DESIGN.

REDUCING VIBRATION.

COMING AMERICAN METHODS.

DETROIT (Mich.), Sept 10. Widened use of both aluminium and rubber in cars next year is forecast in reports of what aiitomobile engineers are working on. The aluminium comes in new alloy metals whose advantages are malleability, strength and lightness, while the rubber will reduce noise and vibration in engine and chassis parts. Lightness of parts, it is argued, also means' a better chance for engineers to produce silence and smoothness of operation, with vibration cut to the minimum and no rough period at any point in the speed range. Aluminium alloy castings have been commonly used in crankcases and gear boxes, and latterly in pistons and gear boxes. Now the engineers are putting alloys into connecting rods, cylinders, combustion heads, and even carburettors and manifolds. In some cases alloys have found their way into wheels, rear axles and brake shoes. Custom 'builders have been utilising hardened aluminium for the metal parts of the finest body coachwork. One maker recently brought out an engine, said to be the first of its kind, in which, an

alloy of chrome nickel was employed. It was said to give seven times the strength of iron. Saving in weight through alloy metals is a factor _in increased power and acceleration being built into engines as they are improved from season to season, on the theory that the lighter car with, the factor of strength provided requires less power to move it, and .therefore has faster getaway and more speed. The contention is that the lighter car cannot only move faster, but that because it is light it can be stopped in less time and with less braking force, and therefore is safer to drive. One of the newest applications of aluminium i 3 in a process which not only hardens it but gives a surface which cannot be scratched or tarnished, together with, properties that allow the metal to resist salt water and corrosive acids. The newest treatment, it is said, will allow radiator shells to be finished in harmony with body colour schemes of cars. It is also being tried out on pistons and engine parts, the assertion •being that entire assemblies, including piston rings, grooves and bearings, can be surfaced and hardened by one dipping. Further uses are being found for rubber by the engineers, who are putting it into new places on the chassis to check vibration. Its use for engine supports has become common. In tliis application research, has found new ways of preserving tensile strength and thereby lengthening the life of the "engine mounting. A rubber mounting on the fan has been found to make that unit, quieter, andv also to function as a vibration dampener for the engine. There is reported, too, increasing interest in rubber insulated universal joints and in steering gears in which rubber forms a part of the mechanism. Rubber also is to be used to eliminate the smaller mechanical joints in the braking system and control rods. One maker reports more than 400 parts in one car made of this material. Improvement of engine manufacturing processes also has been extended to take in metal-'to-metal contacts from which, noise has to be eliminated. An instance is that of Continental, which in its power plants now uses a special machine to burnish, bearings to a mirror-like surface, said to average more than 98 per cent of actual as the engineers rate it. Years ago crankshaft bearings were "broached out," the word "broach" being used in the sense of punching. If a finished bearing showed 85 per cent of the required surface it was passed, This method, being imperfect, was replaced by hand scraping, which gave a 90 per cent result, and then in turn became obsolete when the burnishing machine came in.