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).
Article detailing the design and operation of a new torsional-vibration damper invented by Edwin Thege.
| Identifier | ExFiles\Box 132\1\ scan0123 | |
| Date | 11th March 1939 | |
| 344 1116 A New Torsional-Vibration Damper Fig. 1—Torsional vibration damper designed for a seven-cylinder two-stroke engine of 1280 hp. A NEW type of torsional-vibration damper invented by Edwin Thege and built by the Aktiebolaget Atlas Diesel in Stockholm, Sweden, is said to have met all requirements with respect to damping power, simplicity of design, and ease of maintenance. A drawing of the damper, partly in section, is shown in Fig. 1. It comprises a hub, 1, bolted to the shaft whose vibrations are to be damped, and a rim or damping mass, 2, free to move angularly on the hub. The hub supports the rim at two different diameters, with a good sliding fit, but the angle through which the rim can move relative to the hub is limited by stops, 3. In its oscillating movement on the hub the damping mass is guided by side plates 4 and 5, which in turn are guided radially by bronze rings 6 and 7. In regular operation the damping mass has an oscillating motion on the hub, which is limited as to amplitude, not by the stops, 3, but by an oil cushion formed in the spaces between the inwardly-projecting parts of the damping mass and the outwardly projecting parts of the hub. Oil is introduced into the damper from the nearest engine bearing, through suitable channels. From there it is conducted through a groove communicating with a corresponding groove on the damping mass to the damping chambers. It fills these chambers, and it escapes from these through similar grooves on the smaller periphery of the hub to suitable discharge channels. The oil, of course, cannot absorb blows of the damping mass unless it is confined, and the grooves therefore are so designed that in certain extreme positions they cut off communication with the chambers. Between these extreme positions the damping mass moves freely, the only retarding force then being the friction at the sliding surfaces. For proper operation of the damper it is essential that there be no air in the damping chambers, and provisions are therefore made in the design so that any air which may be carried along with the oil will be separated out and collect in a central cavity in the hub, from which it escapes through tube 8. As the oil enters the damping chambers at their large diameter and escapes from them at the smaller diameter, the chambers are always kept filled by centrifugal force, and a high oil pressure in the feed line is not required. The method of operation of the vibration damper is as follows: Suppose that the hub is momentarily moving in the direction T, in which case the damping mass will be moving in the direction S. After a certain movement has occurred, the oil channels to chamber V will be cut off, and an impact on the oil cushion in that chamber will take place. The movement of the hub will be modified by this impact, depending on the elasticity of the oil cushion, the moments of inertia of the hub and the damping mass, and the relative speed of the hub and the mass. By the impact the direction of motion of the damping mass is reversed, and it will then move in the direction T at the same velocity (Turn to page 349, please) Fig. 2—Damper designed for a twelve-cylinder two-stroke V engine March 11, 1939 Automotive Industries | ||