From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
The advantages and performance of Super-Suspension anti-friction plates compared to standard laminated springs.
| Identifier | ExFiles\Box 154\1\ scan0035 | |
| Date | 15th December 1930 guessed | |
| - 2 - lubricant from the surfaces of the springs most needing it, and where the contact pressure is highest. Super-Suspension anti-friction plates definitely remove this disadvantage, and virtually enable the advantages of maintained lubrication to be retained over extended periods of use. The effect is in fact more pronounced than might be anticipated from comparison of the dry stiff spring, with the well lubricated condition, for in the latter case there often remains more frictional damping effect than is desirable and this can be initially reduced by the application of the ball bearing plates. Those not well acquainted with the problem of spring suspension design sometimes overlook the necessity for retention of damping or controlling action, and fail to realise that this inherent property of the laminated spring accounts very largely for its continued use, in preference to other forms, through many years of vehicle development. But constancy in action has not hitherto characterised its use, and in securing improvement in this respect, the Super-Suspension device represents a useful development in practice. Under working conditions the movement of vehicle springs requires to be very rapid and any hampering action, particularly in the early stage of flexure, has marked influence upon the intensity of the shocks conveyed to the vehicle. The reduction of static friction by the use of these anti-friction plates renders the springs more immediately responsive, and by reducing the total disturbance of the spring carried load, and the unsprung chassis weight, correspondingly limits the intensity of the shocks and stresses originated by road roughness. In other words the more immediate response and greater flexure of the springs in the early stage of disturbance, obviates the greater ultimate disturbance and shock due to the delayed action of an unduly friction bound spring. Or to parody a well known proverb "a yield in time avoids nine". It is not opportune in this report to enter into detailed consideration of the many factors of which account must be taken in spring suspension design, and among which the spring itself is necessarily prominent, but it is desirable to refer to the results of observation. I have, at present, had opportunities of witnessing the effect of fitting the Super-Suspension plates to two vehicles, one with solid tyres and one with pneumatic tyres, and of comparing the riding comfort with and without these devices. In both cases I had no difficulty in deciding that improvement had been effected as shown by easier and softer riding at different speeds over ordinary and rough road surfaces. In these cases the fitting of the plates was carried out under my observation, and constituted the sole alteration of the conditions of test. The springs were left in the condition in which they happened to be on arrival of the vehicles, at your works, and received no lubrication of plates or shackle links and pins, or other adjustment. In the case of the pneumatic tyred motor car the springs were found to be well lubricated throughout, and with the solid tyred motor lorry lubrication was satisfactory; except in the case of the rear spring plates, which were becoming dry, but had not rusted. When travelling in the solid tyred motor lorry at a speed of 18 to 20 miles per hour, with and without load, the improvement in riding became very noticeable after fitting the Super-Suspension plates, and I retain the impression of a remarkable change to smooth easy travel after the normal hard running on solid tyres. In order to supplement personal impression by observing the movement of the springs, in relation to the chassis and body, I used an indicator, which permitted the range of deflection and recoil to be noted. These observations confirmed the anticipation of easier motion of greater amplitude over fairly good road surface, when the anti-friction plates are in use, and over rough road surface easier motion, but of little increased amplitude, so far as the springs are concerned. As already stated the motion of the body and of the load carried by it is very noticeably smoother and easier. | ||