DAMPING VIBRATION

Evening Post, Volume CVI, Issue 11, 14 July 1928, Page 18

DAMPING VIBRATION

EXPEDIENT OP RUBBER ' - Although it would be.untrue tc say that motor-car design has reached finality, it is a fact that manufacturers on' thewhole prefer to keep to conventional ideas and experiment in the direction of refining existing designs, rather than developing new principles of. construction. The greatest importance is placed on the elimination of vibration and any noises of an objectionable nature, and -to- this end- the modern engine is extremely web balanced, while damping devices for ab-, Borbing some of the vibration" which' is inseparable from an engine in which reciprocating motion is v converted to a rotary movement, no matter how well the parts are balanced, have been invented and are in constant use. ■ • Whilst not forgetting the importance of removing as much of this vibration as possible, engineers have not been slow to appreciate the value of confining to its source what cannot be removed. It is the vibration which is transmitted through the chassic and body panels which is Such a worry to the motorist. In order to isolate this vibration in the engine various expedients have, been adopted. v _ Probably the most successful material for preventing its transmission to tha frame is rubber, and the car in which rubber is not interposed in some way between the engine bearer arms and the car frame is rapidly becoming the exception rather than the rule. In some cases quite heavy rubber blocks are used to take the weight, while in others, where the engine retaining bolts lie horizontally, they are inserted in bushings made of this material. FLEXIBLE MOUNTING. Tho idea in all cases where rubber is used is to obtain a fairly flexible mounting capable of absorbing engine vibration before it has a chanco to reach the frame. Rubber blocks, how-

iover,-are not the only things used for I the purpose A noted British fum attacks the i subject in an entuely different way In this car miniature friction type shock absorbers, operating in identically the same way as tho familiar dovices designed for controlling the | springs, are attached.to tho front oi" the engine. ■' T» another car ttc engine is attached to the frame by short laminated leaf springs; while in still another,, case a, complete semi-elliptical transverse spring provides the front, > engine mounting. * Examination of-"a - modern molor-car of^gOod class will discloso that th-< idea pfr using rubber-'ita cheek vibration and nojsp is applied- -to many other parts f>£iihe>, vehicle. It is now quite com,nib)i''.practice to interpose rubber bc•tween tho body and tho chassis frame ,-while -many of the small controls likely, to set up rattles are mounted on rubber bushings. Although a comparatively recent do-1 velopment, the idea of mounting tho | ends of the road springß in either rubber blocks or suspending them by] rubber impregnated fabric is now quite familiar to most drivers, ahd both of these two schemes represent a ' very , important step forward in motor-car design, for not only do they eliminate shackle-belt rattles, but to a slight extent they absorb road shocks. :