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).
Page from an automotive journal detailing a GM rear-engined design, with illustrations of the transmission, clutch, and powerplant mounting.
| Identifier | ExFiles\Box 128\3\ scan0037 | |
| Date | 22th April 1939 | |
| 524 GM REAR-ENGINED DESIGN Fig. 5—Section of transmission and friction clutch, with detail of the vibration damper A, clutch shaft; B, hollow primary shaft of transmission; C, clutch throw-out bearing; D, collar on clutch shaft serving as one member of friction damper; E, pressure plate; F, floating washer; G, Belleville washers serving as clutch springs. the car, and also because air taken in through louvers at the rear of the body generally contains more dirt in suspension and, therefore, deposits more dirt in the engine compartment. By using only a small radiator at the rear, these objections are minimized. Moreover, the fan needed to obtain the proper cooling effect with the engine idling can be driven by simple means. Fig. 4 shows the way in which the various elements of the cooling system are connected. The front radiators may be provided with automatic shutters. In the vehicle referred to, the engine and transmission are mounted as a unit between the rear wheels and have the final drive located between them. A conical friction clutch is provided, and is located outside the transmission housing, close to one side of the body. This necessitates making the primary shaft of the transmission hollow and passing through it a shaft which connects the engine to the clutch at the far end thereof. The central shaft necessarily has to be kept small in diameter, as otherwise the pinions on the primary shaft and the center distance between transmission shafts would become too large, and it was found that with this arrangement there was considerable torsional vibration. This is overcome by interposing a torsional vibration damper of the friction-disc type between the forward end of the hollow transmission shaft and the clutch shaft. The friction damper is combined with the clutch spring, which latter consists of a number of Belleville washers. To disengage the clutch, the central shaft is shifted axially with relation to the hollow shaft, by means of a conventional throwout collar, throwout bearing, and yoke. From Fig. 5 it can be seen that the car has no direct drive; the power is always transmitted from the primary to the secondary shaft of the transmission, and from the inner end of the latter through spur gears to the differential. The powerplant is detachably connected to the vehicle for support on resiliently mounted road wheels. This makes is easy to remove the whole unit when major repairs are required. A transverse tube forms a backbone for the assembly, and from the ends of this tube extend flexibly supported crank arms on which the spindles for the road wheels are carried. The transverse tube supports the powerplant, from which latter universally jointed shafts extend to the drive wheels. Provisions are made for mounting the body frame at points on the tube adjacent to the wheel mountings. In addition to being supported on the transverse tube, the powerplant is braced to the body structure by a series of diagonal struts. An important feature of the mounting is the use in both the main support and the supplemental bracing of rubber connections designed to insulate and reduce the transmission of engine vibration to the body. Fig. 6 shows the general arrangement of the mounting. One patent covers the friction clutch, which is shown in partial section. Fig. 6—Mounting of powerplant on tubular cross member and bracing to body walls A, rib pressed in partition or cross wall of body; B. tubular member extending inward and downward to cross tube D; C, horizontal brace for cross tube D; E,E,E,E, braces extending from top of powerplant to body side walls; F,F, wheel-driving shafts; G and H, members of (Dubonnet-type) suspension. Cross tube D is clamped to the semi-cylindrical ends of the brackets formed by members B and C, and the entire rear assembly, including the wheels, can be removed after taking out a few bolts. April 22, 1939 Automotive Industries | ||