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).
Descriptive page on the Frazer Nash-B.M.W. 2-litre Chassis, detailing the rear axle, front axle, steering, and suspension systems.
| Identifier | ExFiles\Box 126\3\ scan0144 | |
| Date | 1st October 1936 guessed | |
| 5 The Frazer Nash-B.M.W. 2-litre Chassis—contd. at the other end the corresponding fork has a splined shaft fitting in internal splines in the propeller tube. The final drive is through spiral bevel pinions. For the standard model the reduction is 4.3 : 1, the alternative for the sports model known as Type 66 being 3.9 : 1. The pinion is supported immediately behind the teeth by a robust roller bearing, while at the front end the shank is mounted in a combined journal and thrust bearing. A distance bush is fitted between the two bearings, a ring nut nipping the two bearings and the distance bush between itself and the front face of the bevel pinion, while the rear bearing is mounted in a sleeve screwed into the outer casing, thus providing a means for adjusting the mesh of the gears. The crown wheel is mounted by bolts to the outside of the differential cage, the differential gear being of the bevel type. Taper roller bearings are fitted on each side of the differential cage, the axle being of the semi-floating type. The extremities of the one-piece steel axle casing terminate in a flange bolted to the brake bracket and the housing for the single ball bearing on which the wheel runs. Front axle. There is, of course, no front axle in the orthodox sense. The frame terminates in a short cross-member, and on the upper part of this is mounted the single transverse spring which provides the front suspension. Each end of this spring is attached by a bolt passing through its eye to ears on the upper part of the pivot pin, while at the lower end of the pin is a boss to which is attached the forked end of one half of a wishbone lever, the other half being attached by a bolt to the main lever. At the wide end, the lever is closed by a sleeve and pin passing through bosses arranged on the front cross-member, and in which two ball journal bearings are fitted. At the centre of this sleeve is a short vertical lever terminating in a cam which bears on the piston of a hydraulic shock absorber. It should be noticed, however, that the oil only acts in one direction, the piston being returned by a coil spring. A needle-valve adjustment controls the rate of oil flow. In the event of spring breakage, the wishbone levers and shock absorber are sufficiently robust to support the wheel. Front wheel brake. The stub axle is a particularly strong construction, and is formed in one with the brake bracket. The hub runs on two journal ball bearings having a distance piece between them. Generous radii are provided at each change of diameter in this member. Steering layout. Rear suspension. At the rear end of the chassis two semi-elliptic springs are fitted, anchored beneath the rear axle. Rubber pads are fitted above the axle to check the blow should the axle come in contact with the frame under exceptionally severe conditions. The clearance at this point, however, is so great that this would seem an unlikely occurrence. The shackles are at the rear end, a commendable point being that a pipe from the one-shot chassis-lubrication system is led to the upper bush of the shackle, a communicating hole being drilled down the shackle on the far side communicating with the lower bush. Hydraulic shock absorbers are fitted, being mounted on the rear cross-member and attached to the axle through links fitted with oil-less graphite bushes. In this instance the oil in the shock absorber acts in both directions. Steering. Each wheel is independently steered. The steering column is supported at the upper end from a dashboard bracket, in which is fitted an oil-less graphite bush, the casing for which is split and adjustable and thus provides a means of eliminating rattles. At the lower end is fitted a Hardy-type rubber universal joint just above the rack and pinion gear, which forms the operating mechanism. The whole of this gear is mounted in rather a large bracket attached to the front cross-member by two setscrews. Referring to the steering head, it should be noticed that adjustment for up and down movement of the pinion is provided for by a nut at the upper end, while adjustment for taking up back lash is provided by an eccentric bush. The rack is attached by a pin to the centre of a transverse rod terminating in two ball-ended pins. These in turn fit in the ends of the tubes which transmit the motion to the stub axles. The construction of the spherically ended joint is worth noting. The outer member, which has a partly semi-spherical recess is so shaped that it must be fitted over the ball-ended pin prior to assembly. Inside the tube is a bush, which also has a partial spherical depression, and this is held in contact by a short spring, the whole assembly being held together by a single bolt passing through the tube. Each joint is protected from General arrangement of independent wheel steering. | ||