SILENT GEARING.

Putaruru Press, Volume I, Issue 10, 20 December 1923, Page 1

SILENT GEARING.

- * A MODERN ESSENTIAL. One 01. uic greatest advances in postwar drsign is exemplified by tlic high degree of silence attained by gearing of ::'i descriptions timing wheels, gearlsi.x pinions, and final drives, though it must be admitted that even the best gear boxes leave room for improvement on the indirect gears. in the majority of eases the causes of noisy running were iimccurn:«: workmanship and faulty production me! hods rather than poor design. The gears were first c-ut. then heattreated. and finally plunged into oil or brine. It was found that the distortion set..up'by 1 he-sudden immersion of the It it gear in tlic cool liquid entirely negatived the care taken in the earlier i operations. To remedy this, the teeth were roughly shaped prior to hardeiir ieg, and then ground to the correct; profile a. the last operation. Special machines were developed for this pro-ce-ss, and a ver; high standard of accuracy made passible. It had previously Is.-fii foun 1 in some gear-boxes that the length cf the shafts carrying the gears was such that they sprang apart or deflected under load 1 r* such an extent that the correct meshing of the gears •.as affected. This was overcome by i

more compact des'gn, reducing tbc s’-. -, i f h-ngih die.mo; or, or by additional Ai the same time, it vv:t - found that, con .tin designs of easing (ended to ini easily any gear noise, and careful work iii l!:is respect provided yet another step in the direct 1 on of silence. Where the gears have to slide i and out of mesh, as on the spline secondary shaft of a gear-box, it is so dom an easy matter to ensure coneoii t licity with the bon*. The gear i usually allowed to sent between th splines, as this permits a straight grim on the bore, but the accurat machining of the l»ea rag portion ill* spline: ! • Ins f’l pro,mils >o:.:e dim r mi Jess a t- !i is m-. T-i for tlt hi.ai 'per;:l i«>n. Some makers hr ho;, s.-pn t* (hr shafts iii iieu o splines; ’with this arrangement tin shaft can be ground ail over, and i: ings. The st •“night bevds used la the him .1 rives of many cars were a source of !rouble to most manufacturers; in a large number of cases tin.* noise wasaused by the deflection under powui >f the overhung pinion shaft; improve mont in this respect was effected 1>; increasing the shaft diameter, bringing the bearing nearer the pinion, 01 where space permitted, by placing ai additional bearing on the far side o iiie pinion. The last method was th most effective, and was adopted. !> several high-grade manufacturers.