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).
Description of the operation and acting forces within a roller-based friction clutch.
| Identifier | WestWitteringFiles\R\2October1927-November-1927\ 92 | |
| Date | 1st May 1927 guessed | |
| -2- In this ring-space are placed a number of cylindrical rollers of hard steel (shown in red on fig. 1), and, owing to the shape of the surfaces of the neck and collar, these rollers are constrained to lie obliquely to the axis of the shaft at a constant angle ∝. The shape of the collar is so adjusted that, in the symmetrical position shown by fig. 1, the fit is loose. The pressure of a spring, which may be applied to either EF or CD as desired, will then ensure either:- (1) A close fit of the surfaces AC, BD{Mr Berend} and a loose fit of the parts AE, BF; or (2) A close fit of AE, BF and a loose fit of AC, BD.{Mr Berend} In case (1), if the primary is made to revolve in the sense indicated by the black arrow in fig. 1, the collar will set the rollers rotating in the direction shown by the red arrow. Owing to the inclination of these rollers, this tends to displace the collar, by a screw motion, in the direction X to Y, thereby reducing the space between the surfaces AC, BD{Mr Berend} and the corresponding portion of the neck of the shaft. This compression increases the grip upon the rollers and causes them to jam. The parts of the rollers shown below AB (in fig. 1) are free, since, on that side of AB, the spacing between the constraining surfaces has been increased. The clutch then acts as a friction clutch and the primary and secondary revolve together. 2. ACTING FORCES. The collar will exert upon a roller, at a point of contact, a normal pressure and two components of friction, one along and the other across, the generating line of the roller. The main tendency of relative slip will be along the generating line of the roller. It is thus the first component of friction which is | ||