EP0523129A1

EP0523129A1 - A rotary engine

Info

Publication number: EP0523129A1
Application number: EP19910907244
Authority: EP
Inventors: Bernard Crawshaw Leggat
Original assignee: Individual
Current assignee: Individual
Priority date: 1990-04-02
Filing date: 1991-04-02
Publication date: 1993-01-20
Also published as: WO1991015659A1; JPH05506900A; GB9007372D0

Abstract

Moteur rotatif comprenant une structure (H) dans laquelle quatre pistons sont logés et montés sur des arbres co-axiaux (6b, 7a) pour permettre une rotation concentrique dans une chambre annulaire (C), les arbres étant mobiles séparément par l'intermédiaire de leviers (6, 7) et de pivots (6a, 7b), et lesquels sont connectés par des liaisons (3a, 3b) à un moyen amélioré permettant de transmettre des mouvements synchrones variables aux éléments de pistons de manière que les gaz peuvent être aspirés dans la chambre (C) par l'intermédiaire d'un orifice d'admission, pour être comprimés, expansés et déchargés par l'intermédiaire d'un orifice d'échappement. Ledit moyen amélioré comprend un élément d'arbre (S) comportant une partie excentrique (1) sur laquelle est monté rotatif un élément de collier (2), auquel est fixé un engrenage interne (4) permettant un engrènement avec un engrenage fixe doté de dents externes, le rapport de dents situé sur les engrenages interne et externe étant respectivement de 3:2.Rotary motor comprising a structure (H) in which four pistons are housed and mounted on coaxial shafts (6b, 7a) to allow concentric rotation in an annular chamber (C), the shafts being movable separately by means of levers (6, 7) and pivots (6a, 7b), which are connected by links (3a, 3b) to an improved means allowing variable synchronous movements to be transmitted to the piston elements so that gases can be sucked in into the chamber (C) via an inlet port, to be compressed, expanded and discharged via an exhaust port. Said improved means comprises a shaft element (S) comprising an eccentric part (1) on which a collar element (2) is rotatably mounted, to which is fixed an internal gear (4) allowing engagement with a fixed gear provided with external teeth, the ratio of teeth on the internal and external gears being 3: 2 respectively.

Description

A ROTARY ENGINE

This invention relates to rotary engines and aims to provide improved means for controlling differential piston movements in rotary engines. Such engine proposals are known and typically comprise pistons which are mounted in pairs onto shafts for concentric rotation about a common axis and housed within a single continuous annular chamber or cylinder, and wherein also is provided means for effecting differential movements to each pair of rotating pistons whereby gases may be drawn into the engine via an inlet port, and compressed, expanded, and expelled therefrom via an exhaust port. This combustion cycle having been previously described and established in principle, for example:- in 1928 Yoder- Morris discloses in UK Patent No. 278,648:- According to this patent a rotary engine has means for controlling the relative movement between piston members whereby a charge of expansible medium is sucked in, compressed, expanded and discharged, the said controlling means comprising basically a jointed parallelogram which is provided with rollers adapted to move upon a cam path.

It is an object of the present invention to provide a rotary piston engine having improved means for controlling the relative movement between pairs of piston members whereby the reguired cycles are carried out ie, induction, compression, expansion and exhaust, and whereby the combined variable piston movements are transformed via the controlling means into uniform rotary movement at the engine output shaft.

According to one aspect of the present invention, a 5 rotary engine comprises a casing having an inlet port, an outlet port, and a continuous annular chamber; two pairs of piston members mounted within the annular chamber, the piston members being connected in diametrically opposed pairs and mounted to piston shafts for concentric 0 rotation about a common axis the pistons being drivably connected to an outlet shaft rotatably mounted upon the common axis, characterised in that said output shaft is provided with an eccentric portion, a collar member being rotatably mounted upon the eccentric portion, the collar 5 member having an internally toothed gear mounted for movement therewith, the internally toothed gear movably engaging an externally toothed stationary gear mounted on the common axis, the ratio of the gear teeth on the internal gear to those on the external gear being 3:2, a 0 pair of links, each link being attached adjacent one end to the collar member at diametrically opposite positions by means of pivotal connections, said links being attached eccentrically one on to each of the two piston shafts by means of pivotal connections.

---.5 The invention will now be described by way of example with reference to the accompanying drawings in which:- Figure 1 is a schematic sectional view, and demonstrates how the component parts of the present invention may be incorporated within and positioned along an engine axis.

Figure 2 is a schematic view at VI in Figure 1 of the elements which comprise (together with Figure 3) the piston controlling means ie:- Crankshaft (1), Collar member (2) , Links (3a) (3b) , Levers (6) (7) , Pivots (6a) (2a) (2b) (7b) , and Counterbalance weight (8) which is secured adjacent the BDC side of the crankshaft.

Figure 3 is a schematic view at V2 in Figure 1 of the internally toothed gear (4) which is engaged eccentrically (E) with an externally toothed stationary gear (5) positioned upon and concentric with the engine axis (A) , the ratio of gear teeth provided on the internal and external gears being respectively 3:2.

Figures 4 - 8 are a schematic sequence in which the piston controlling mechanism is rotated through one expansion cycle and continues on next expansion cycle in Figure 9; gears are not depicted in these diagrams.

Figures 10 - 15 are a schematic sequence and are viewed from V3 in Figure 1 to show the general piston arrangement and combustion sequence, and wherein two pair of pistons (a-c and b-d) are secured one each onto diametrically opposite sides of co-axial shafts (6b and 7a in Figure 1) and mounted for concentric rotation within a continuous annular chamber (C in Figure 1) formed within the housing (H) , and wherein also is provided an inlet port (IN) and an exhaust port (EX) the four engine phases being effected simultaneously through the sequence ie:- Induction between pistons (d-σ) Compression between pistons (a-d) Expansion between pistons (a-b) and exhaust between pistons (b-c) .

Referring now to the drawings, there is shown an engine comprising a casing (H) having an annular chamber (C) within which pistons (a, b, c and d) are housed and mounted in pairs (a-c and b-d) onto diametrically opposite sides of shafts (6b and 7a) , one shaft being sleeved upon the other for rotation about a common axis (A) . The shafts (6b and 7a) are each provided with a lever or flange portion (6, 7), levers (6 and 7) being disposed at 180° with respect to one another, when the pistons (a-c and b-d) on each shaft (6b, 7a) are disposed at 90° to the pistons (b-d and a-c) on the other shaft (7a, 6b). Each lever (6, 7) is provided with connecting means in the form of links (3a, 3b) whereby the combined variable movement of the pistons (a-c and b-d) may be transformed via the controlling and power transmitting mechanism, to effect power transmission.

The said controlling and transmitting mechanism comprises a shaft (S) rotatably mounted on the common or collective engine axis (A) , the shaft (S) being provided with or having formed upon it an eccentric portion (1) in the manner of a crank shaft, and upon which is rotatably mounted a collar member (2) . The collar member (2) is provided with or has formed upon it an internally toothed gear (4) for movable engagement with an externally toothed stationary gear (5) which is positioned on and concentric with the engine axis (A) . The ratio of the gear teeth provided on the internal and external gears (4 and 5) is respectively 3:2.

The connecting means are links (3a, 3b) are attached at one end, one to each of the lever portions (6, 7) of the piston shafts (6b, 7a) by means of pivotal connections (6a, 7b) , the other ends of the links (3a, 3b) being connected to the collar member (2) at diametrically opposite positions, by means of pivotal connections (2a and 2b) .

The principle of operation of the controlling and transmitting mechanism is now described with reference to rotation of shaft (S) which will in fact be the output shaft of the engine. It will be appreciated that although when the engine is running, it will be the motion of the pistons (a, b, c and d) that drive the shaft (S) the operation of the controlling and transmitting means and the motions imposed thereon upon the shafts (6b and 7a) and pistons (a, b, c and d) mounted thereon will be the same.

Upon rotation of shaft (S) the eccentric (1) will drive the collar member (2) and the internally toothed gear (4) provided thereon, in an orbital motion. Engagement between the teeth of the internally toothed gear (4) and the externally toothed stationary gear (5) will cause the collar member (2) and the internally toothed gear (4) to rotate eccentrically, the speed of rotation being one third that of the shaft (S) .

In the frame of reference of the rotating collar member (2) about the centre axis (A) , the pivotal connections (2a and 2b) of links (3a and 3b) respectively, to the collar member (2) , will move in circular paths. The links (3a and 3b) and levers (6 and 7) act as crank rockers so that the circular movement of pivotal connections (2a and 2b) will cause levers (6 and 7) to rock backwards and forwards, imposing an oscillation on the rotation of shafts (6b and 7a). As pivotal connections (2a and 2b) are attached to the collar member (2) at diametrically opposite positions, the oscillations on shafts (6b and 7a) will be 180° out of phase causing the pistons (a-c and b-d) mounted thereon to move together and apart producing compression and expansion strokes.

It will be appreciated that the degree of oscillation will depend upon the eccentricity of the crank (1) which sets the diameter of the circular path of the pivotal connections (2a and 2b) , the length of the links (3a and 3b) and the lengths of the levers (6 and 7) . Typically, these dimensions will be set to give an oscillation in the range of 10° to 30° in both directions, which when movement of the pistons (a-c and b-d) mounted on each shaft (6b, 7a) is taken into account will give an effective stroke of 40° to 120°.

Figures 4 to 9 show a schematic sequence of the control mechanism showing the actual movement of the pivotal connections (2a and 2b) as the collar member (2) rotates with the pistons (a, b, c and d) , so as to impose the oscillation on the rotation of shafts (6b and 7a) , thereby controlling movement of the pistons (a, b, c and d) . The arrangement of the inlet port, exhaust port and ignition device in order to utilise the various expansion and compression strokes provided by the controlling mechanism, to provide induction, compression, expansion and exhaust strokes of the engine, are illustrated in Figures 10 to 15.

It will be appreciated that many changes in construction and widely different embodiments will suggest themselves without departing from the spirit or scope of the invention, the disclosures and descriptions herein being purely illustrative and not intended to be in any sense limiting.

Claims

l. A rotary engine comprising a casing (H) having an inlet port (IN) , an outlet port (EX) , and a continuous annular chamber (C) ; two pairs of piston members (a-c and b-d) mounted within the annular chamber (C) , the piston members (a-c and b-d) being connected in diametrically opposed pairs and mounted to piston shafts (6b, 7a) for concentric rotation about a common axis (A) the pistons (a-c and b-d) being drivably connected to an outlet shaft (S) rotatably mounted upon the common axis (A) , characterised in that said output shaft (S) is provided with an eccentric portion (1) , a collar member (2) being rotatably mounted upon the eccentric portion (1) , the collar member (2) having an internally toothed gear (4) mounted for movement therewith, the internally toothed gear (4) movably engaging an externally toothed stationary gear (5) mounted on the common axis (A) , the ratio of the gear teeth on the internal gear to those on the external gear being 3:2, a pair of links (3a, 3b), each link (3a, 3b) being attached adjacent one end to the collar member (2) at diametrically opposite positions by means of pivotal connections (2a, 2b), said links (3a, 3b) being attached eccentrically one on to each of the two piston shafts (6b, 7a) by means of pivotal connections (6a, 7b) .

2. A rotary engine according to Claim 1 characterised in that the links (3a, 3b) are attached to the levers (6, 7) mounted for rotation on the piston shafts (6b, 7a).

3. A rotary engine according to Claim 2 characterised in that the levers (6, 7) are secured to the piston shafts (6b, 7a) , such that when the pistons (a-c and b-d) on one piston shaft (6b, 7a) are at 90° to the pistons (b-d and a-c) on the other piston shaft (7a, 6b) one lever (6, 7) will be at 180° with respect to the other lever (7, 6).

4. An engine according to any one of Claims 1 to 3 characterised in that the eccentricity of the crank (1) , the lengths of the links (3a, 3b) and/or the length of the levers (6, 7) are selected to provide an oscillation in rotation of each of the piston shafts (6b, 7a) in the range + 10° to ± 30°.