Patent GB-926801-A (GB)
IPC: F02B53/00
Filed: 1959-10-06
Abstract: 926,801. Rotary engines. NSU MOTORENWERKE, and WANKEL G.m.b.H. Oct. 6, 1959 [Oct. 7, 1958; April 23, 1959; July 17, 1959], No. 33816/59. Class 110 (2). In a rotary piston unit comprising either a stationary or rotary outer body having a multi-lobed inner periphery in continuous sliding engagement with the apices of an eccentrically rotatable rotor to form variable volume working chambers and internally and externally toothed gearing fixed to the rotor and outer body respectively, the rotor is journalled on an eccentric supported on bearing pins extending inwardly from the outer body end walls along the middle axis of the outer body. As shown in Fig. 1, the outer body 4 is rotatable and comprises end walls 5, 6 and a shell 7 having an epitrochoid-shaped, two-lobed inner periphery, see Fig. 2, in continuous engagement with the apices of a substantially triangular rotor 12 supported on a stationary eccentric 3 rigidly connected to the outer casing 1 by means of a pin 2 terminating in a disc 3a. The end walls 5, 6 are furnished with bearing pins 8, 9 respectively, extending inwardly along the middle of the outer body 4. Sleeve bearings 33, 34 fitted between the rotor and the eccentric and sleeve bearings 35, 36 fitted between the eccentric and the bearing pins are disposed so that the bearing loads resulting from the gaseous pressure in the variable volume chambers 21 acting radially on the rotor and outer body are substantially balanced to reduce the bending moments and therefore the size of the bearing pins 8, 9 and the pin 2. External teeth 15 on the bearing pin 8 engage internal teeth on a wheel 14 fixed to the rotor 12 so that the speed of the outer body 4 to the rotor is in the ratio 3: 2. When operating as an internal combustion engine, air is drawn in through a cavity 19 and a filter and mixed in an axial passage 17 in the driving shaft 16 with fuel admitted through a pipe 22 and nozzle assembly 23 in the pin 2 before passing into the chambers 21. A throttle 24 on movement of the pipe 22 controls the fuel-air mixture. Cooling fins 26, 27 are fitted on the outer body 4 and on rotation of the body generate a current of air between inlet openings 28 and an outlet 29. The rotor 12 and outer body 4 may be liquid-cooled, liquid entering a channel 40, Fig. 7, and passing through cavities 42, 43, 44 in the end walls 5, 6 and the shell 7 to cool the body 4. Part of this liquid leaves through a channel 45 and the remainder passes through a channel 46 into a cavity 47 within the rotor. Radial channels 48 opening into the cavity 47 radially beyond the bearings and the gear teeth return the liquid inwardly through centrifugal pressure to axially directed outlet channels 49. In another embodiment, the outer body 4, Fig. 4, having end walls 5<SP>1</SP>, 61 and a shell 7<SP>1</SP> is stationary and the pin 21 and eccentric 3<SP>1</SP> rotatably supported. In a modification of the Fig. 4 embodiment, the teeth 15 on the bearing pin 8 extend through the outer body end wall 5<SP>1</SP> with a consequential reduction in the diameter of this pin as compared with the diameter of the bearing pin 9. As a result of this the bearings 33<SP>1</SP>, 34<SP>1</SP>, 35<SP>1</SP>, 36<SP>1</SP> are unequally disposed on either side of the median line through the rotor so that the bearing loads are apportioned out according to bearing strengths. A hard steel bushing is inserted between the teeth 15 and the end wall 5<SP>1</SP> which is normally made of a light alloy.