US3485218A

US3485218A - Rotary piston machines

Info

Publication number: US3485218A
Application number: US672871A
Authority: US
Inventors: John Michael Clarke
Original assignee: National Research Development Corp UK
Current assignee: National Research Development Corp UK
Priority date: 1967-10-04
Filing date: 1967-10-04
Publication date: 1969-12-23
Anticipated expiration: 1986-12-23

Description

Dec. 23, 1969 .1. M. CLARKE 3,485,218

ROTARY PISTON MACHINES Filed 002.. 4, 1967 12 SheetsSheet 1 FIG. I.

WM FIG. 2.

Inventor AiZor neyS Dec. 23 1969 CLARKE 3,485,218

ROTARY PI STON MACHINES Filed Oct. 4. 1967 12 Sheets-Sheet 2 WM Q Inventor ,CLM A! tys Dec. 23, 1969 J. M. CLARKE ROTARY PISTON MACHINES Filed Oct. 4, 1967 12 Sheets-Sheet 5 4a 49 32 36 I533 F 25 46 J n f kk I g a 42 I \X I \3. J Y

FIG. 4.

Inventor M v Gui/MM Attarneys Dec. 23, 1969 M, CLARKE 3,485,218

ROTARY PISTON MACHINES Filed Oct. 4. 1967 12 Sheets-Sheet 4 FIG. 5.

W M Inventor Attorneys Dec. 23, 1969 J. M. CLARKE 3,

ROTARY PISTON MACHINES Filed Oct. 4. 1967 12 Sheets-Sheet 6 Inventor W03 Mm T Warneys Dec. 23, 1969 J. M. CLARKE 3,485,218

ROTARY PISTON MACHINES Filed Oct. 4, 1967 12 Sheets-Sheet 7 ANNE-Ill:

Inventor By 4' W At orneys Dec. 23, 1969 Y J. M. CLARKE 3,485,218

ROTARY PISTON MACHINES Filed Oct. 4, 1967 12 Sheets-Sheet 8 K ea 70 L 74 69 72 r 73 NW ifxigm FIG. 9a.

4 68 7 73M 69 \Y M 0 FIG.9b.

FIG.9c.

Inventar Mama "Mm Attorneys Dec. 23, 1969 (:LARKE 3,485,218

ROTARY PISTON MACHINES Filed Oct. 4. 1967 12 Sheets-Sheet 9 a9 a3 a: as m Inventor 1A ttar n eys Dec. 23, 1969 J. M. LARKE 3,485,218

ROTARY P I STON MACHINES Filed Oct. 4, 1967 12 Sheets-Sheet 10 FIG. II.

Inventor By MAM, r W

A! rnzys Dec. 23, 1969 J. M. CLARKE v 3,485,218

ROTARY PISTON MACHINES Filed 001.. 4. 1967 12 Sheets-Sheet 11 Inventor W T Mn Aitgrneys Dec. 23, 1969 CLARKE 3,485,218

ROTARY P I STON MACHINES Filed Oct. 4, 1967 12 Sheets-Sheet 12 N :07' 107 I05 p no: 3 107' N MS m V 4 A U Y 0 0 I I082? 5 I083 T v w v Q Q R 2:: U v v m \o S u ky V v 'r a) s e no I084 a T W roe o FIG. :3

W ML Inventor M521 T W At orneys US. Cl. 123-8 15 Claims ABSTRACT OF THE DISCLOSURE An internal combustion engine comprises a shaft having an inclined portion carrying a disc-like rotor capable of separate rotation and connected to the shaft through gearing. A casing containing the shaft and rotor has a circumferential channel with walls diverging from a point where they are narrowly spaced and which surround a web portion of the rotor connecting part spherical hub and rim portions arranged to partially enclose the channel. Seals are provided on the faces of the rotor web to bear against the channel Walls so that the space within the channel is divided into a series of chambers which vary in volume in accordance with rotation of the rotor. Gas inlet and exhaust ports provided in the channel walls are put into communication with the chambers during rotation and gas is drawn into successive chambers to be compressed, passed to other chambers by way of transfer valves and ignited to do useful work on the rotor before passing out of the exhaust.

Various alternative arrangements of basically similar configuration are also described, differing primarily in the positions of gas ports, shape of the rotor or configuration of the channel to facilitate operation as two or four stroke engines, pumps or combined engines and pumps.

The invention relates to rotary piston machines.

Various proposals have been made from time to time for machines having a rotary piston arrangement usually comprising some form of rotor revolving within a specially shaped casing. Such machines are particularly attractive compared with those having reciprocating pistons in that generally, dynamic balancing is much less of a problem and they have fewer moving parts.

However, a recurrent problem in many of these machines is the difficulty of maintaining adequate sealing between a rotor and its casing whereby leakage of operating fluid can be contained within such limits as would make efficient and reasonably trouble-free working a practicable proposition. This problem is particularly critical where sealing members are carried by rotating components such that rubbing surfaces subjected to centrifugal loads are required to pass over port openings.

The invention is concerned with rotary piston machines which inter alia lend themselves to the provision of simple and effective sealing arrangements.

A rotary machine according to the invention includes a casing, a shaft having an inclined portion, and a substantially disc-like rotor mounted coaxially on the said inclined portion, the casing having a circumferential convergent-divergent channel formed therein to constitute a working volume wherein the channel encloses a part of the rotor and seals are formed between the channel and said part of the rotor to divide the working volume into a plurality of chambers, the extent of individual chambers being varied during rotation of the rotor.

In a preferred form of the invention the shaft and the rotor rotate at different rates according to the ratio:

nited States Patent Patented Dec. 23, 1969 ice where (.0 is the rotation rate of the shaft,

m is the rotation rate of the rotor relative to the shaft,

and

N is the number of rotations of the shaft for each rotatlon of the rotor (and also the number of chambers).

In another preferred form of the invention, the casing also rotates, the relationship of the rotating components being according to the expression:

m: +l)( i J ill 1 10 where (0 is the rotation rate of the casing.

This ensures that the same relationship between the sealing surfaces of the channel and the rotor is repeated after each cycle of the shaft, the geometry being the same at every l/N part of the circumference of the rotor.

It is a feature of the invention that ports for the entry and exit of Working fluid are provided which are fixed relative to the channel and operated by the rotation of the rotor.

By varying the location of the ports, either with or without variations of the rotor and channel configurations, a machine according to the invention can operate as a two-stroke or four-stroke internal combustion engine, a pump, or a combined internal combustion engine and pump.

Various embodiments of the invention will now be described by way of example with reference to the accompanying diagrammatic drawings of which:

FIGURE 1 is an axial section of the basic parts of a machine which embodies essential features of the invention,

FIGURE 2 is a similar view of a part of the machine of FIGURE 1 embodying an additional preferred feature of the invention,

FIGURE 3 is a diagram showing the relative motions involved in FIGURE 2,

FIGURES 4 and 5 are longitudinal sections of an internal combustion engine at different phases of operation,

FIGURE 6 is an elevation of a rotor forming a part of the engine of FIGURES 4 and 5,

FIGURES 7a to 7 are developed cylindrical sections through the working space of the engine of FIGURES 4 and 5 at sequential intervals of its operating cycle,

FIGURE 8 is a longitudinal section of another form of internal combustion engine,

FIGURES 9a to are developed cylindrical sections through the working space of the engine of FIGURE 8 at sequential intervals of its working cycle,

FIGURES 10a to 10 are developed cylindrical sections through the working space of a pump,

FIGURES 11 and 12 are longitudinal sections of a further form of internal combustion engine at different phases of operation and taken at right angles to each other and FIGURES 13a to 13 are developed cylindrical sections of the working space of the engine of FIGURES 11 and 12 taken on the line of the rotor tip therein at sequential intervals of its operating cycle.

Referring to FIGURE 1, a shaft 1 carried in a fixed bearing 2 has an oblique portiton 3 disposed at an acute angle a. A rotor in the form of a disc 4 is carried on the oblique portion of the shaft by means of a bearing 5 whereby the polar axis of the disc is maintained in the same direction relative to the oblique portion. The bearing also permits the disc to rotate independently of the shaft.

Assuming for the moment that the bearing is fixed, (i.e., the shaft and the disc together constitute a swash plate), the disc will apparently wobble when the shaft is rotated. An the shaft and disc rotate the rim of the disc (or a point thereon) will appear to describe a transverse are though in fact any point on the disc will be describing a true circular path parallel to the transverse axis of the disc.

If, however, the disc is held from rotation and the shaft rotated, a point (conveniently on a side surface) of the disc will merely oscillate.

By choosing an intermediate relative velocity, the aforesaid point will oscillate sideways whilst rotating, thus following a sinous path on the surface of a sphere.

It will be seen that where the disc is enclosed within a suitably shaped casing 6 it can be made to sweep over a sector-shaped region within the casing.

A part spherical annular member 7 extending outwards from the side of the disc co-operates with a similarly shaped portion 8 of the casing to close off the aforesaid sector-shaped region to give an enclosed annular space.

By virtue of the foregoing explanation, points on the same side surface of the disc can be maintained in close proximity to a boundary of the swept region whereby a seal 9 may be maintained to divide the enclosed annular space circumfereutially. Provided two or more seals are used the annular space can be subdivided into a number of chambers the respective volumes of which will undergo cyclic variation during shaft rotation.

A necessary condition for the application of this arrangement to a positive displacement device is that the cyclic variation be accurately reproduced since if there is a mismatching between the cycles of the shaft and of the disc, the seals will not necessarily follow the same path in relation to the housing. It is therefore necessary for the geometry of the disc to be repeated every l/Nth part of its circumference where N is the number of rotations of the shaft for each rotation of the disc.

If is the rotation rate of the disc relative to the shaft and ca is the rotation rate of the shaft, in order for the geometry to be repeated each shaft revolution:

The casing might also rotate at a rate 10 (being a fixed proportion of ar about the same axis as the shaft when this expression becomes:

io N in Of more fundamental interest however are the devices having a value of w /w chosen to give an inherently balanced oscillatory system. It can be shown that if:

where I is the moment of inertia of the disc about its polar axis and I is the moment of inertia of the rotor about any axis normal to the polar axis; then the bearing on the inclined portion of the shaft need transmit no inertia loads and the mechanism can run at high speed without vibration as though all members were simply rotating.

The conditions 1 and 2 are exclusive (i.e., not compatible) since inherent balance is not possible in the first case. A compromise using a stationary casing can however be achieved in a machine having sliding seals to form two chambers at each side of its rotor (i.e., N :2), a disc-like rotor (I /I /2) and in which the angle between the axes of the shaft and its oblique portion is small (i.e., cos e21).

This type of machine which will hereafter be referred to as a two-stroke unit is the most satisfactory from the inertia loading point.

A machine in which three chambers are formed by the rotor seals will be referred to as a four-stroke unit. The larger values of the couples required to cause oscillatory 4 motion of the rotor within a stationary casing can be tolerated because of the simplicity of the arrangements for porting fluid to and from the machine which are thereby facilitated.

The residual couples can be completely balanced by diametrically opposed masses at opposite ends of the shaft. Because the masses can be disposed to have a large moment and only a proportion of the oscillating couple remains to be balanced, these masses can be quite small compared with that of the disc. Balancing is assisted by the oblique portion of the shaft, particularly if this is of large diameter and much shorter than its diameter.

FIGURE 2 illustrates a mechanism whereby a rotary oscillatory motion can be imparted to the disc, the same reference numerals as before being used where applicable. In this case the outer edge of the annular member 7 is formed with gear teeth 10 and a fixed gear wheel 11 is mounted co-axially about the shaft 1. As the shaft is rotated the gear teeth 10 will be brought successively into engagement with those of the fixed gear to impart a rotary motion to the disc the rate of which is determined by the rate of rotation of the shaft and the ratio between the numbers of teeth on the annular member and on the fixed gear.

The considerations involved appear diagrammatically in FIGURE 3 in which Z is a fixed direction corresponding to the axis of the shaft, K is the axis of the disc (and of the oblique portion of the shaft) and S2 is the instantaneous axis of rotation (or point of engagement of the gears) and ,8 the angle between the disc axis and the instantaneous axis.

It is possible to obtain diverse types of motion by various combinations of oz and B (e.g., simple rotation about the axis of symmetry when et=fi=0 or as a slowly precessing spinning top when ([320) but where ,BzNoc the required rotating oscillation motion can be obtained.

Returning to FIGURE 2, the rate of rotation of the disc can be Varied by causing the gear 11 to rotate in step with the shaft 1 as by interposing a tarin of gears to give a desired ratio.

It is essential that the disc rotates at a negative angular velocity relative to the shaft. (For example, the disc rotates in the same direction as the shaft but at a lower rate.)

Referring to FIGURE 4, an internal combustion twostroke engine comprises a casing 21 in which is mounted a shaft 22 having a centrally-disposed boss portion 23. The boss is obliquely inclined relative to the shaft its axis passing through that of the shaft on the centre line of the boss at an acute angle. A tapered roller thrust bearing 24 mounted on the boss carries a rotor which can rotate separately from the shaft. The rotor comprises a hub portion 25 and an outer rim 26 connected by an annular web 27 which extends radially between the hub and the rim. The web is curved circumferentially so that it extends between positions at one side of the rotor transverse centre plane at positions 180 apart as shown in FIGURE 4 to corresponding positions at the other side of the said plane in the course of a quarter of the circumference as shown in FIGURE 5. The shape of the web 27 is nidicated in FIGURE 6, which shows the rotor in elevation in the same operating position as in FIGURE 4, the web and other parts within the rim appearing in dotted lines. Two lobes (of which one is shown at located diametrically opposite each other extend radially across the web on one side of it. Two

further lobes

121, 122, displaced at right angles from those mentioned above are similarly arranged at the other side of the web. Those portions of the sides of the webs between the lobes are shaped so that, with the rotor in place in the casing, there will be clearance between the said portions and the later walls of the casing at least during certain phases of rotation and the volumes of the chambers so defined will be varied during rotation of the rotor as will be detailed later. With further reference to FIGURE 4, the circumferential outer surfaces of the

hub

28, 29 at either side of the web form part of a sphere and the web itself is located within an annular channel formed in the casing,

lateral walls

30, 31 defining the channel being sinuous in a circumferential sense and more widely spaced apart at the bottom of the casing than at the top where their clearance of the web is minimal. Thus a developed cylindrical section of the chnanel would show a convergent-divergent form, the widest portion being at the lower end as indicated at E-E in FIGURE 4, the narrowest portion corresponding to the position indicated at F-F. The spherical surfaces of the hub co-operate with internal spherical surfaces on the

casing

32, 33 disposed on opposite sides of the aforesaid channel while the rim 26 is provided with internal

spherical surfaces

34, 35 generated from the same centre as those of the hub, which are arranged to co-operate with the externally

spherical surfaces

36, 37 formed on the casing. Circumferentially-extending resilient strip seals 38, 39 are provided in the

surfaces

32, 33 adjacent to the sides of the channel and

similar seals

40, 41 are provided in the

surfaces

36 and 37. Gas ports 42, 43 are provided in the casing communicating with the channel near its widest point and on opposite sides of its vertical centre-line. The periphery of the rim of the rotor also has a spherical surface and a circumfernetial seal 44 carried in an encircling wall 45 of the casing bears on this surface. The shaft 22 carries a toothed gear 46 at its left hand end whereby it drives a bevel gear 47 mounted co-axially about the shaft through reduction gearing 48, 49, 50.

An annular bevel gear 51 formed on the rotor hub meshes obliquely with the bevel gear 47 so that rotation of the shaft causes the rotor to rotate in the same direction at half speed.

Sliding seals extending radially are located in the lobes of the rotor web to bear against the lateral walls of the channel. There are two 52, 53 at diametrically opposite points on the right hand side of the web and two 54, 55 in the left hand side of the web also diametrically opposed and spaced 90 apart from those first mentioned.

On rotation of the shaft 22, the boss 23 and its associated bearing 24 will describe a conical path around the shaft, the apex of the cone being centred on the intersection of the axis of the boss with the axis of the shaft. At the same time the bevel gear 47 will cause the rotor to rotate on the bearing 24, the intermeshing point with the bevel gear 51 rolling around in step with the rotation of the shaft.

By reasons of the considerations discussed earlier, the

seals

52, 53, 54, 55 will follow sinusoidal paths whereby they will remain in contact with their respective walls of the channel in the casing.

The movement of the rotor and seals may be followed in FIGURES 7a to 7 which represent a developed cylindrival section through the web of the rotor and the sides of the channel the movement of the rotor being from left to right. The locations EE and F-F in FIGURE 7a correspond to the diametrically opposite locations indicated in FIGURE 4 and FIGURES 7b to 7 show successive positions of the rotor at 30 intervals corresponding to 60 intervals in the rotation of the shaft, i.e., at the 60, 120, 180, 240 and 320 positions from that shown in FIGURE 7a. Points GG and H-H in FIGURE 7d correspond to the similarly-marked points in FIGURE 5 which shows the position when the shaft has rotated through 180 and the rot r through 90 relative to FIGURE 4. The movement of the two faces of the rotor web is also illustrated in these drawings.

Referring to FIGURES 7a to 7 in conjunction with FIGURE 4, it can be seen that a chamber A contained between the

seals

52 and 53 and the front face of the web and the side of the channel 31 becomes progressively less in volume as the rotor moves from the position shown in FIGURE 7a to that in FIGURE 7d where it has become virtually non-existent, the face of the rotor between the

aforementioned seals

52, 53 being almost in surface contact with the side of the channel. Continued rotation of the rotor as in FIGURES 7e and 7 results in the resurgence of the chamber whose further behaviour is as the chamber B in FIGURES 7a to 7 again taken in sequence. Similarly a chamber C virtually not present in FIGURE 7a begins to enlarge in FIGURE 71; as the portion of the rotor Web between the

seals

54, 55 begins to move away from the left hand wall 30 of the passage progressively becoming greater in volume with continued rotation of the rotor to the position shown in FIGURE 7f after which its behaviour is as the chamber D in the sequence through FIGURES 7a to 7 When the inclination of the rotor relative to the shaft is as in FIGURE 4 the rim 26 towards the bottom of the rotor has moved to the right and no longer encloses the wall 30 of the channel in this region which is thus open to the passage 42 and the gas from the passage can flow to the chamber D until such time as the inclination of the rotor is such that the rim 26 again comes into contact with the lower portion of the seal 40 (i.e., the position shown in FIGURE 7d), and the gas will be trapped within the chamber D to be compressed as it decreases in volume. A transfer valve 56 is provided in the web of the rotor and is arranged so that a pre-determined gas pressure within the chamber D will cause the valve to open (FIGURE 7e) allowing the gas to flow into the chamber B, this process being assisted by further reduction in the chamber D. Referring to FIGURE 7a the aforesaid gas must be regarded as being contained in the chamber A of this figure and the pressure within the chamber has returned the transfer valve 56 to its seating.

Alternatively the transfer valve might be arranged to be opened and closed by mechanical means such as a cam ring. Continued rotation of the rotor (FIGURE 7b) results in further compression of the gas. A combustion chamber 57 formed in the casing has a connecting port 58 extending through the front wall 31 of the channel and when the rotor reaches the position shown in FIG- URE 7c the compressed gas begins to pass into the combustion chamber.

At the position of FIGURE 7d virtually all the gas is contained in the combustion chamber, at which point the gas is ignited in conventional manner. Since the chamber A is enlarging again, the expanding gas will pass thereto and do useful mechanical work on the rotor which can be transmitted to the main shaft 22 through the bearing 24 and the boss 23. Turning once again to FIGURE 7a expanding gas is contained in chamber B and on reaching the position shown in FIGURE 7b the rim 2:6 of the rotor moves to the left clear of the lower portion of the seal 39 thus bringing the passage 43 into communication with the chamber B from which the burned gases thereby pass to exhaust (see also FIGURE 5). The opening of the transfer valve 56 resulting in compressed gas flowing into the chamber B from the chamber D completes the purging of the exhaust gases after which the exhaust passage is again sealed off by the rim 26.

In the embodiment of FIGURE 8 which is another form of two-stroke engine, a rotor mounted on a shaft as in the previous example and driven in similar manner comprises a hub portion 61 carrying a web 62 as in the previous case and of the same sinuous configuration. The rotor is enclosed within a casing 63 but in this construction is not provided with a rim, the circumferential surface of the web 63 having working clearance from a part spherical inner surface of the casing which forms part of a channel as before. The said circumferential surface is provided with a sealing member 64 which bears radially outwardly against the inner surface of the casing to prevent gas leakage from one side of the web to the other. Strip seals 65, 66 extend radially in the right hand face of the web outwardly from the hub at diametrically opposite locations and bear against the right hand wall 67 of the channel. Similar seals 68, 69 (shown in FIGURES 9a to 90) in the left hand face of the web and spaced 90 apart from those just mentioned bear against the left hand inner wall 70 of the casing. Two openings 71, 72 (of which one 71 is shown in FIGURE 8) are formed in the casing at either side of the vertical plane containing the axis of the shaft. These openings are also symmetrically disposed about the centre line of the channel and constitute gas inlet and outlet ports to and from the channel.

The movement of the rotor and seals in this case is set out in FIGURES 9a to 90, which show a developed cylindrical section of FIGURE 8 at 120 intervals of shaft rotation with the locations KK and LL of FIGURE 9a corresponding to those of FIGURE 8.

' The port 71 is open to the chamber M until cut off by movement of the rotor (FIGURE 9b) after which compression takes place until the seal 68 passes the connecting port 73 of a combustion chamber 74 in the wall 70 (FIG- URE 90). Further movement of the rotor reduces the volume of the chamber M still further until all of the gas is contained in the chamber when ignition is arranged to occur. The expanding gas passes into resurgent chamber N to do useful work on the rotor until the exhaust port 72 is opened. No transfer port is provided in this engine in which a similar sequence of operations takes place on both sides of the rotor web, a second connecting port 75 and combustion chamber 76 being provided in the wall 67. Some degree of pressurising of the infiowing gas (e.g., supercharging) would probably be advantageous with this arrangement. A useful scavenging effect is obtained in that the exhaust from one chamber commences just before the opposite chamber is closed off from the exhaust port.

It is envisaged that the disposition of the ports might be varied to induce a gas charge through a port in the spherical surface of the hub thus making use of centrifugal effects.

In another variation of the arrangement of FIGURE 8 a different arrangement of ports is used and the rotor driven by external means to enable operation as a pump.

The operating sequence is shown in FIGURES 10a to 10f in which

inlet ports

81, 82 are formed in the

walls

83, 84 of a convergent-divergent annular channel opposite to each other at a median point of the divergent portion (relative to the movement of a rotor).

Outlet ports

85, 86, likewise communicate with the convergent portion.

Tuming of the rotor, the web 87 of Which is provided with

seals

88, 89, 90 and 91 arranged as previously described, will result in fluid being drawn through the inlet ports and expelled through the outlets as indicated by the arrows.

With a compressible fluid and a high compression ratio there may be a tendency for reverse flow to occur and it may be necessary to incorporate non-return valves or other appropriate means to obviate this.

By a suitable arrangement of ports, a self-contained pump unit is feasible, a combustible gas being introduced and burned at one side of a rotor to give power for pumping operations on the other side.

In the double-acting four stroke engine of FIGURES 11 and 12 the basic arrangement of shaft, boss, rotor hub and timing gears is as in the previous embodiments except that the gearing is arranged to give a 3/1 ratio between the shaft and the rotor instead of 2/ 1.

The arrangement of the rotor web and its associated annular channel differs considerably however.

The channel is of double convergent-divergent form in cylinducal section, being narrower at the top and bottom of the engine than at the sides as may be seen by comparing the two figures in which the channel is defined by walls 161, 102. The rotor web 103 is again of sinuous form its disposition relative to hub 104 varying between the locations in FIGURES 11 and 12 in which the rotor is shown as displaced by a quarter revolution.

Recesses

105, 106 are formed in each face of the web at 120 intervals, those on one face being mid-way between those on the opposite face. These recesses, as will be explained later, act as combustion chambers. Radially extending sliding

seals

107, 108 are provided in lobes on the web, three to each face, opposite to the recesses in the other face and bear against their adjacent channel walls.

Reference should now be made to FIGURES 13a to 13; which represent a peripheral development of the channel of FIGURES 11 and 12 on the line of the rotor tip. The movement of the rotor is again from left to right and the locations NN and PP in FIGURE 13a correspond to the diametrically opposite locations indicated in FIG- URE 12. FIGURES 13b to 13) show successive positions of the rotor at 20 intervals, corresponding to 60 intervals in the rotation of the shaft.

The chamber Q will be seen to be at its maximum extent in FIGURE 13a and also to be in communication with exhaust port 199 formed in channel wall 102. The chamber becomes progressively reduced in volume with movement of the rotor and any gases contained therein are constrained to pass through the port 10R by seals 103 108 When the rotor reaches the position shown in FIGURE 132, the seal 198 has effectively passed over inlet port also formed in channel wall 1412 to admit an inflow of gas into the chamber Q until exhaust port 109 is closed off by further movement of the rotor.

The next sequence of events is illustrated by the changes in volume of the chamber R which is progressively enlarged whilst in communication with the inlet port 110 until this is closed off by the seal 108 (FIGURE 13 when the volume begins to be reduced thus starting to compress the gas which has flowed into it.

The final sequence of events appears from the changes in volume of the chamber S. Compression is continuing in FIGURE 13a and in FIGURE 13b the charge of gas is effectively contained within the recess 106 at which it is ignited. The resultant expansion of the gas reacts on the rotor to propel it and do useful mechanical work. The volume of the chamber S is increased during this stage and is eventually connected with the exhaust port 109 by movement of the seal 108 after which the cycle continues as already described.

A similar sequence of operations takes place on the opposite side of the rotor web, exhaust and inlet ports 111 and 112 respectively being provided in the channel wall 101.

Thus there are two power strokes for each revolution of the shaft and six for each revolution of the rotor.

By varying the relative positions of the inlet and exhaust points the extent of the overlap of the exhaust and induction strokes can be altered as required to give the most effective purging of the exhaust gases.

It is envisaged that the casing of the engine might with advantage also be rotated in addition to the shaft and the rotor. In this way inherent balance can be achieved with the rotor having the ideal ratio of rotational to oscillation frequencies, the bearings not then being required to exert any inertial loads.

Such an arrangement would be suitable for use as part of a gas generator system employing turbo machinery where it would be particularly compatible because of its axial symmetry, high swept volume in relation to size. and high speed shaft output.

It will be obvious that innumerable detail variations of a more or less conventional nature might be incorporated into the embodiments previously described to assist in maintenance or manufacture or to give improved performance. For instance, instead of combustion chambers being formed in an engine casing, detachable combustion chambers could be screwed into suitable ports in the casing walls and these combustion chambers could conveniently incorporate fuel injectors, air only being compressed by movement of the rotor.

Again, the casings might be constructed in several parts one or more of which could be readily removable to allow access to the rotor or other components. One such construction comprises two end housings containing shaft supporting bearings and having inclined faces which form the sides of a circumferential channel with their peripheries connected by a ring housing comprising a section of a hollow sphere and wider at one side than at the other. Preferably such a ring housing would be in two parts, one of which could be readily detachable.

Differing porting arrangements from those described can also be envisaged particularly for two-stroke engines, split exhaust and single inlet ports being one possibility.

In another variation of a less general nature, rubbing faces of the rotor can be made fiat (rather than conical) by a suitable selection of the angles at which seals are mounted.

It is also possible to dispense with separate radial seals, especially in machines rotating at high speeds with low working pressures, by making the side surfaces of circumferential channels slightly spherical and profiling the rubbing faces of the rotor so as to maintain effective line contact during rotation.

I claim:

1. A rotary piston machine comprising a casing, a shaft mounted for rotation in the casing and having an oblique portion, a substantially disc-like rotor mounted co-axially on the said oblique portion for rotation relative to the shaft, lateral walls of sinuous form in the casing defining therein an annular channel of convergent-divergent configuration as seen in cylindrical section taken co-axially with the shaft, said channel constituting a Working space containing a part of the rotor, which part is situated substantially at the periphery of the rotor, means operative to constrain the rotor to continuous rotation relative to the channel, and seals formed between the lateral walls of the channel and said part of the rotor so as to divide the working space into a plurality of chambers, the volume of each of these chambers being varied during rotation of the rotor.

2. A rotary piston machine according to claim 1 in which means are provided to cause the shaft and the r t0r to rotate at different velocities according to the ratio:

where a is the rotation rate of the shaft, is the rotation rate of the rotor relative to the shaft,

and N is the number of rotations of the shaft during each complete rotation of the rotor. 3. A rotary piston machine according to claim 1 in which means are provided to cause the shaft, the rotor and the casing to rotate at different velocities according to the expression:

E: 1+- -)(1-- N lo where m is the rotation rate of the shaft,

@0 is the rotation rate of the rotor relative to the shaft,

@ is the rotation rate of the casing being a fixed proportion of m and N is the number of rotations of the shaft for each rotation of the rotor.

4. A rotary piston machine according to claim 1 comprising toothed gearing interposed between the shaft and the rotor and arranged so that rotation of one of these will cause the other to rotate.

5. A rotary piston machine according to claim 4 in which the gearing includes a bevel gear operatively connected to the shaft and a further bevel gear formed on the rotor, the said bevel gears meshing together.

6. A rotary piston machine according to claim 1 in which the rotor comprises a hub portion and an annular web extending radially from the hub portion, the web being the aforesaid part of the rotor contained within the annular channel in the casing.

7. A rotary piston machine according to claim 6 in which said seals comprise circumferentially-spaced radially-extending sealing surfaces provided in the web and arranged to bear against the walls of the channel.

8. A rotary piston machine according to claim 7 in which the sealing surfaces are constituted by sliding seals.

9. A rotary piston machine according to claim 7 comprising two diametrically-opposed sealing surfaces at each side of the web and means constraining the rotor to rotate at half the rate of rotation of the shaft.

10. A rotary piston machine according to claim 9 having sealing surfaces at one side of the Web spaced circumferentially midway between sealing surfaces at the other side of the web portion.

11. A rotary piston machine according to claim 10 comprising means in the web for enabling communication between chambers on opposite sides of the web.

12. A rotary piston machine according to claim 11 in which the said means comprises a transfer valve.

13. A rotary piston machine according to claim 7 comprising three-equally spaced sealing surfaces at each side of the web, the sealing surfaces at one side of the Web being spaced circumferentially mid-way between the sealing surfaces at the other side of the web lateral walls defining a channel with two convergent-divergent portions, as seen in cylindrical section co-axial with the shaft, so that its width is at a maximum at diametrically-opposite points and at a minimum at further diametricall 'opposite points located circumferentially mid-way between the points of maximum width and means constraining the rotor to rotate at one-third of the rate of rotation of the shaft.

14. A rotary piston machine according to claim 13 comprising combustion recesses located between the sealing surfaces in each side face of the web portion of the rotor.

15. A rotary piston machine according to claim 1 in which ports for the entry and exit of working fluid are provided, the ports being fixed relative to the channel and arranged to be periodically and sequentially opened and closed by the rotor in the course of rotation.

References Cited UNITED STATES PATENTS 1,912,634 6/1933 Gray l2385 2,328,775 9/1943 Betzen i 12385 2,997,000 8/1961 Becker et al. 103-133 LAURENCE M. GOODRIDGE, Primary Examiner US. Cl. XR.