CA1307744C - Rotating piston machine - Google Patents

Abstract

Abstract A rotating piston machine has a casing with a shaft borne in the casing . In an annular space there are arranged rotating elements which bear in sealing manner against the walls of the annular space . Each ro-tating element has four outwardly extending sector-shaped vanes . The two rotating elements are arranged coaxially; their vanes en-gage in one another, so that in each case one vane of the one rotating element is arranged between two vanes of the other rotating element. By a cam track control it is achieved that, on rotation of the shaft , both rotating elements execute rotations with cyclic changes in the speed of ro-tation and the distances between the vanes The cam track control has in this case for each rotating element eight rolling elements which interact with an inner and an outer curved track non-positively and free from play.

Description

Jurgen Schukey, 1 307744 Hamburg, Rotating Piston Machine ~ he invention relates to a rotating piston machine uith a casing, with a shaft borne in the casing, with an annular space, in which two rotating elements are arranged ~nd agai(1st the wa~ls of which, in which intake and dis~
charge openings for the working medium are provided, the rotating elements bear ;n sealing manner, each rotating element having four radially outwardly extending sector-shaped vanes, the two rotating elements being arranged co-axially and their vanes engaging in one another in such away that in each case one vane of the one rotating element is arranged between two vanes of the other rotating ele-ment, a cam track control being provided, by wllich, on ro-tation of the shaft, both rotating elements execute rota-tions with cyclic changes in the speed of rotation and in the distances between the vanes of the two rotating ele-ments, and the cam track control having inner cam rings which are connected fixedly in terms of rotation to the shaft.
Various rotating piston machines are known, which all have, however, various disadvantages~ In particular, the problem of balance frequently occurs, so that the known rotating piston machines frequently run very out of round, which on the one hand causes vibration and noise, and on the other hand also subjects the bearings to very high stresses.
Various disadvantages also occur in the case of a known rotating piston machine of the type mentioned at the beginning (~ritish Patent Specification 299,767). As can be convincingly deduced from simple geometrical considera-tions, the guidance of the rolling elements between the inner cam track and the outer rollers cannot take place there without play. This is not possible with any cam geometry of the inner cam track. The force transmission via the variously borne rollers is very small, so that only a low efficiency can be achieved which is out of all proportion to the moved masses. No interaction takes place io the r~gion of the load cllanges, that is to say the rever-sal points of the cam track; there are dead points there.
The bearing of the rollers is not described and obviously S not solved. Owing to the said problems, it must be expec-ted that a rotating piston machine corresponding to the ci-tation would run at least very unevenly and have a lo~ ef-f l C l ellCy .
The object consists in creating a rotating piston machine which operates very effectively and ~ith which es-sentially no problems due to uneven running occur.
The solution according to the invention consists in that the cam track controL has outer cam rings which are connected fixedly in terms of rotation to one rotating ele-ment, that in each case four of the rolling elements rollbetween one inner cam ring and one outer cam ring each, and rolling elements which are displaceable in radiaL direction, held undisplaceably in circumferential direction by a cage -~ connected to the casing, and that two pairs of inner/outer ZO cam rings per rotating element are provided with correspond-ing rolling elements.
~ y the cam track controL according to the invention, the two rotating elements can be set in motion in such a way that, on their rotation, the volume of the working spaces on both their sides is changed cyclically in accordance with intake and discharge openings, so that the desired mode of operation is achieved.
The force transmission takes place in this case by the shortest route in each case via two cam track surfaces.
The flux of force is ensured at every point of the cam track.
Play-free running is also ensured. The cam geometry can in this case be designed in such a way that uniform accelera-tion values are achieved, as 3 result of which the acceler-ation torque can be reduced.
Eight rolling elements per rotating element are con-stantly active free from play and non-pos;tively. The force transmission takes place both by lifting work of the rolling elements and by traction between the cam tracks and the _ 3 _ l 3 0 7 74 4 rolling elements (i.e. rolling of the rolling elements on the cam tracks).
The rotating piston machine can in this case serve, on the one hand, as a compressor, for example for gases.
lt can, however, also operate as an engine if the compres-setJ gases are allowed to flow into a separate combustion chamber, have fuel admitted to them there and if this mix-ture is ignited and the gases subsequently are conducted back into the annular working space in order for them to drive the rotating elements.
If the shaft rotates, and consequently the inner cam ring connected to it fixedly in terms of rotation, said cam ring uill push the rolling element outwards when its rolling surface for the rolling element goes outwards in radial direction upon this rotation. As a result, the outer cam ring is indirectly set in rotation since it has to give way in such a way that the rolling element finds a position in which the rolling track lies radially further outwards on the outer cam ring. In this way, the rotational move-ment of the shaft is transmitted to the outer cam ring andthus to the rotating element. The speed and the variation of this speed are determined in this case by the shape of the track curves on the cam rings. Once the rolling ele-ments have reached the outer-most position, they cannot transmit a torque any longer from the inner cam ring to the outer cam ring. The movement ;s then continued by the sec-ond set of inner/outer cam rings unt;l the f;rst set of inner/outer cam r;ngs can again transmit torque.
It would, admittedly, be conceivable to provide only one of the rotating elements with the cam track control men-tioned and to fix the other directly on the shaft. This so-lution is, however, less favourable since the rotating pis-ton mach;ne can then no longer run evenly. Therefore, a cam track control ;s exped;ently provided for each rotating ele-ment.
If cylindrical rolling elements are chosen, theycannot roll correctly on the cam rings if there are varying distances and thus circumferential lengths of the cam tracks, _ 4 _ 13~7744 but have to slide partially, ~hich is accompanied by fric-tional losses.
It is expediently provided that the rolling elements taper conically on both sides and that the cam rings have, S in radial and axial directions, rolling tracks following a givcn function.
In this way, it can be achieved by suitable choice of the functions that the rolling elements roll evenly and free from friction on the rolling tracks of the inner and of the outer cam ring and do not slide. The axial function for the rolling track is obtained in this case from the radial function. It must be ensured that, ~ith a given rotation of the rolling element about a certain angle, the rolling ele-ment rolls on both tracks without stiding. This takes ptace by changing the effective rolling element diameter in as much as the track is arranged axially displaced at a point at which the effective rolling element diameter has the suitable value on account of the conical shape.
The rolling elements and the cam rings are expedi-ently mirror-symmetrical with respect to a radia( plane. As a result, the rolling elements always rest on two mirror-symmetrical parts of a double rolling track and cannot tilt.
If the cam rings are made up of two mirror-symme-trical halves, they can be produced particularly simply~
~oth cam ring halves then have (apart from the track shape) essentially frustoconical shape, so that the outer ring halves in particular can be produced more easily. In addi-tion, in this way the entire arrangement can be assembled easily.
If the cam rings can at the same time be tensioned in axial direction by their being an intermediate space also provided bet~een the cam ring halves, the cam ring halves can, by axial tension, be pressed firmly against the roll-ing elements, so that the entire arrangement is free from play. This tensioning effect in axial direction takes place advantageously by spring loading.
As already mentioned, two cam ring pairs have to be provided per rotating element. If it is provided that the one set of cam rings of the pair of sets is idel1tical to, but fitted the other way round from, the other set of cam rings of the pair of cam rings and if the rolling elements of the one set of cam rings are offset by 45 with respect to the set of the other cam rings, on the one hand the two sets of rolling elements can be fitted quite closely to each other ;n axial direction, which reduces the overall size.
The balance is also better in these conditions. By using identicaL cam rings for both sets, the number of different cam rings also becomes very small. Only two outer cam ring halves and two inner cam ring halves have to be produced.
As a result of the second set of cam rings being fitted the other way round, in other uords that the function running in circumferential direction runs in precisely the opposite direction to that of the respectively other set, the contin-uous force transmission is made possible, so that whenever - no force is transm;tted by one set, this takes place by the other set.
It is advantageously provided that the vanes of the rotating elements have, in a plane containing the shaft axis, the shape of a square, the one diagonal of which is perpen-dicular to the shaft axis and that the casing consists of two halves, the parting line of which is the centre plane of the annular space, the annular space can thus be produced particularly easily and the machine can be assembled very simply. If a flexible seaL and a tensioning device are also provided bet~een the two casing halves, a better sealing effect can be achieved by stronger clamping of the casing halves, since then the oblique casing halves bear very well against the surfaces of the rotating elements running at 45 to the shaft.
If it is additionally provided that the angular po-sition of the cages with respect to the casing is variable, the position of the intake and discharge openings can also be changed. Although then the cyclic movement of the two rotating elements remains the same even with respect to each other, the rotating elements or the working spaces formed between them then coincide at different times-with the 1 3077~

intake and discharge openings, so that the mode of operation of the machine can be changed in a simple way.
In the case of an expedient embodiment, it is fur-ther provided that at least parts of the radially outer wall S are formed by moveable, hollow elements which are provided with seals and uhich, if the contact pressure on the vanes subs;des and there is therefore a poorer sealing effect, are again pressed firmly against the vanes by a leakage flow caused thereby. In this way, a very simple and expedient automatic regulation of the sealing effect between rotating elements and walls of the sealing space is obtained.
The rolling elements in the cages are expediently held with the aid of bearing shells or sliding blocks which are fixed in the cage with the aid of toothings in such a way that they can execute a rolling movement in one direc-tion but are prevented from a movement in a direction per-pendicular thereto.
In many cases, it will be arranged for the input drive, if the rotating piston machine is used as a compres-sor, or the output drive, if the rotating piston machineis used as an engine, to take place at the shaft. However, the two rotating elements or parts connected thereto can also be connected rigidly to the rotor of an engine/genera-tor the stator of which is connected to the casing. In this advantageous embodiment, the input drive, in the case of use of the rotating piston machine as a compressor, does not act on the shaft, but directly on the two rotating ele-ments. The driving speed can in this case be adapted very effectively to the changes in the rotational sPeed of the rotating elements, in particular with use of a disc-rotor engine. Then all that takes place via the shaft is the forced compensation or adaptation, controlled by the roll-ing elements and cam tracks, of the speeds of rotation of the two rotating elements. The same applies corresponding-ly if the rotating piston machine is used as an engine; inthis case, the rotors of disc-rotor generators are rigidly connected to the rotating elements.
~ y the arrangement according to the invention of _ 7 _ 13~7~4~
eight rolling elements per rotating element, which are ar-ranged free from play, the rotating elements are borne ef-1ectively. As a result, in addition to the advantage al-ready mentioned of quiet running and of high efficiency, it is also achieved that additional bearings for the rotat-ing elcments can be dispensed with completely The invention is described below by way of example using advantageous embodiments with reference to the at-tached drawings, in which:
Figure 1 shows a section through a radial plane of the annular space with the two rotating elements;
Figure 2 shows the two rotating elements in differ-ent positions:
Figure 3 shows the principle of the cam track con-trol according to the invention;
Figure 4 shows a section in an axial plane of theshaft through inner cam ring, rolling element and outer cam ring;
Figure 5 shows a view of rolling element and cage parts, seen radially from outs;de;
Figure 6 shows a side view of the inner cam ring;
Figure 7 shows the cam ring of Figure 6 in plan view;
figure 8 shows a side view of the outer cam ring;
F;gure 9 shows the cam ring of Figure 8 in plan view;
Figure 10 shows details of the cage and of the roll-ing element gu;de in ax;al view;
Figure 11 shows a section through the machine of the invention;
Figure 12 shows an axial section through the annular working space in the case of a further embodiment of the in-vention; and Figure 13 shows a further embodiment in similar re-presentation to that of Figure 11.
Figure 1 shows the annular space (1), which is sur-rounded by parts of the casing (2). In the annular space(1) there are the two interengaging rotating elements, which are designed as ;mpellers t3 and 4). The impeller (3) has in this case the vanes t3a, 3b, 3c, and 3d) while the impeller (4) has the vanes (4a, 4b, 4c, and 4d) Both impellers are drive~l by a centrally arranged sllaft (5), il7 a way yet to be described. (6a-6h) denote various intake openings and discharge openings in the front wall of the annular space S (1).
The mode of operation of this arrangement is as follows. If the shaft (5) moves anticlockwise, the impel-lers (3 and 4) are turned clockwise at different speeds in a way yet to be described. In the position shown, for ex-ample, the impeller (4) would turn faster clockwise thanthe impeller (3). In this case, the working space between the impellers (3d and 4a) would increase , so that gas is sucked in through the intake port (6a). At a subsequent time, this intake port (6a) is then closed by the slowly follow;ng vane (3d). From about this moment on, the vane (3d) begins to move faster than the vane (4a), so that the working space between the two vanes is reduced and the gas is compressed until both vanes have moved so far that the working space is over the discharge opening (6b), so that the gas can escape here. At this time, the vane (3d) can be moved up to the vane (4a), so that the gas is fully pressed out here.
This mode of operation can be used both for a com-pressor and for an internal-combustion engine. All that need be provided are combustion spaces, fuel lines, etc.
Figure 2 shows four phases of the operating cycle just described. A new operating cycle commences after a 90 rotation of the two rotating elements.
Figure 3 then shows the principle of the cam track control according to the invention. Shown in the radial sec-tions of Fig~ 3 , on the inside, is an inner cam ring (7) connected fixedly in terms of rotation to the shaft (5) and embraced on the outside by an outer cam ring (8), which is connected to the rotating elements (3, 4). ~etueen the inner and outer cam track rings there are rolling elements (9) at 90 interva(s. The said rolling rings are held firm with respect to the casing (2) by a cage in such a uay that they can only perform a movement radially outuards or inwards, but no movement in the rotational direction of the shaft or of the inner and outer cam rings (7, 8).
If, as can be seen in the transition fro~ the fig-ure on the left of Figure 3 to the centre figure, the inner cam ring (7) turns anticlockwise, due to its outcr contour, the rolling element (9) is pressed downwards. As a result, the outer cam ring (8) is then turned clockwise, since it must give way in this direction in order to create space for the rolling element (9). When the central position is reached, turning is continued by a corresponding movement on another set of inner cam ring, rolling elements and outer cam ring until the posit;on on the right of Figure 3 is reached, which again corresponds to the starting posi-tion on the left. In this way, the rotational movement of the shaft (S) is thus converted into a rotational movement of the rotating elements (3, 4) in the annular space, this rotational movement being uneven however and determined by the curve shape of the inner and outer cam rings (7, 8).
If the rolling elements (9) were cylindrical, they could not roll evenly on the inner and the outer cam ring (7, 8), but they would tend to slide since the track curves are different. This can now be avoided by the rolling ele-ments (9) according to the invention in the shape of a double cone, as is shown in section in Figure 4. There it can be seen that the rolling element (9) has various effec-tive diameters during rolling. For ;nstance, on the left at (10), an average rolling diameter for rolling on the outer cam ring (8) is shown, while on the right at (11) an aver-age rolling diameter for rolling on the inner cam ring (7) is indicated. Average rolling diameters are referred to here, as obviously the contact surface between cam ring and rolling element is not a mathematical line but has a cer-tain width.
As is shown in the figure, the cam rings ~7 and 8) are not designed in one piece, rather they consist of two cam ring halves (7a and 7b and 8a and 8b respectively), which are of mirror-symmetrical design. Only in the region of the rolling track (7c and 8c respectively) is the roll-lo - 1 307744 ing element (9) in contact with these cam ring halves.
The rolling elements are held in a cage, which must be imagined in Figure 4 in front of and behind the rotating element (9). This cage, or part of it, is shown in plan view in Figure 5.
The rolling elements (9) is held by two bearing shells (12), in which the rolling element can turn slid-ingly. The bearing shells have, on the outside, a toothing which engages in a corresponding toothed rack (13) of the cage (14). In this way, the rolling element (9) can indeed move forwards or backwards in Figure 5, i.e. in the case of the rotating piston machine in radial direction, or upwards or down~ards in Figure 4. However, it is hindered from an angular movement with respect to the casing, i.e. a move-ment to the right or left in the case of the representationof Figure 5.
Figure 6 shows a cam inner ring half (7a) in side view;
Figure 7 shows the same cam ring half (7a) in plan view.
The essentially obliquely running outer surface can beseen there, which is arranged in the shape of a truncated cone on which the rolling track (7c) for the rolling eLement (9) is then provided as the raised portion.
As can be seen from Figure 6 and 7, the rolling track (7c) passes, both in radial direction and in axial direction, through a function which corresponds to the desired track control behaviour.
` Figures 8 and 9 correspondingly show a section through an outer cam ring half (8a) (Figure 8) and a plan view (Figure 9). The elevated rolLing track (8c) can also be recognised there.
Figure 10 shows once again in more detail, in axial view partially cut away, the bearing of the rolling elements (9) in the cage (14). The cam rings with the rolling tracks are also indicated there.
Figure 11 shows , in an axial sect;on, one half of the machine according to the ;nvention. The other half of the machine continues here essentially mirror symmetrically Lo til ' lef~
The drive shaft (5) is rotatably borne in the casing (2) by means of a distance sleeve (15) and radial and axial bearings (16, 17) and a casing flange (18). Outside the dis-tance sleeve (1S), there further adjoins a coupling flange (19) and a nut (2û). Inside the distance sleeve (15) there follou the two pairs of inner cam rings, which form inner cam ring (7). There then adjoins to the right a distance sleeve (21), which then lead (sic) to the corresponding in-ner rings (7) on the other side, which are intended for the drive of the other of the tuo rotating elements.
~ y tightening of the nut (ZO), the two halves of the cam inner rings (7) are pushed together via the distance sleeves (15 and 21) and by a corresponding counter-pressure element on the left side (not shoun) of the machine, so that the rolling elements (9) are pressed outuards, to be prec;se against the cam outer rings (8). These likeuise consist of two halves and are arranged fixedly in terms of rotation in a jacket sleeve (22) uhich is connected to the rotating ele-ment (3). Sealing flanges (23) not only hold the outer cam rings (8) firm but also push them against each other in or-der to create a counter pressure here for the pressure of the rolling elements (9). The pushing together of the halves of the inner rings (7) or outer rings (8) may also take place here by means of spring elements.
The cage (14) in uhich the rolling elements (9) are borne, is finally fixed on the casing flange (18) and con-nected fixedly in terms of rotation to the cage on the other side of the arrangement by means of a rack toothing t24). In this uay, the cage is secured in circumferential direction against the casing. The angular setting of the cage t14) with respect to the casing t2) may also be changed by chang-ing the angular setting of the casing flange t18) uith res-pect to the casing t2) by an adjusting bearing (25).
At (26-30), further seals are shown, at (31) a fur-ther seal betueen the casing halves. Finally (3Z) is a slid-ing sleeve betueen cage (14) and rotor (3).

~ Z
As stated, the casing (2) is made up of two halves, the seaL (31) being provided at the parting ~ine (33J of the same. If the sealing effect between the vanes of the rotat-ing elements (3, 4) and the wall of the annular space t1) becomes inferior, by tightening of a bolt taken through the bore (34), it can be effected that the two casing halves are moved closer together, producing a better contact between casing walls and rotating eLements (3, 4) in the annuLar space, as a resuLt of which the sealing effect is improved.
In the case of the embodiment of Figure 12, the vanes (just out of sight in Figure 12) of the rotating ele-ment (3 and 4) are not directly in contact with the casing walL (2), but with a walL eLement (35) which is bourne in a flexible and sealing manner. If said walL element (35) yields, a sealing gap (36) between rotating eLement (3) and eLement (35) widens or a corresponding seaLing gap between rotating element (4) and a corresponding element (37), which corresponds to the element (35) ~idens. As a resuLt, gas under pressure here enters the sealing gap (36) (and corres-Z0 pondingly on the other side) and can pass through an opening (38) into the cavity behind the element (35) and thereby press the latter in the direction of the arrows (39) inwards against the vanes of the rotating elements. In this way, an automatic regulation of the sealing effect is achieved.
In the case of the embodiment of Fig. 13, the rotors 42 of engines or generators 40 are connected directly to the rotating elements 3, 4. Figure 13 shows that the rotor 42 of the engine/generator is connected rigidly to the ro-tating element 3 via the jacket sleeve 22. The same ap-plies correspondingly for a second engine/generator 40 (not shown), which is rigidly connected to the rotating element 4. The stator 41 of said engines/generators is in this case rigidly connected to the casing 2. In the case of this em-bodiment, the input/output drive no longer takes place via the shaft 5. Rather, the rotating elements 3, 4 are driven directly by the engines 40 or the rotating elements 3, 4 drive the generators 4û directly, the forcibLy controlled coordination of the movements of the rotating elements 3 ~ - 13 -and 4 then taking place via the shaft 5.

Claims (14)

1. A rotating piston machine having a casing, a shaft mounted in the casing, an annular space, in which two rotating elements are arranged and against the walls of which, in which walls intake and discharge openings for a working medium are provided, the rotating elements bear in sealing manner, each rotating element having four radially outwardly extending sector-shaped vanes, the two rotating elements being arranged coaxially and their vanes engaging in one another such that in each case one vane of the one rotating element is arranged between two vanes of the other rotating element, a cam track control, by which, on rotation of the shaft, both rotating elements execute rotations with cyclic changes in the speed of rotation and in the distances between the vanes of the two rotating elements, and the cam track control having inner cam rings which are fixedly connected in terms of rotation to the shaft, the cam track control having outer cam rings which are fixedly connected in terms of rotation to one rotating element, and rolling elements which are displaceable in the radial direction, held undisplaceably in the circumferential direction by a cage connected to the casing, in each case four of the rolling elements rolling between one inner cam ring and one outer cam ring each, and two pairs of inner/outer cam rings per rotating element which has such a cam track control being corresponding two sets of four rolling elements.

2. A machine according to claim 1, in which a cam track control is provided for each rotating element.

3. A machine according to Claim 1, in which the rolling elements taper conically on both sides and the cam rings have, in radial and axial direction, rolling tracks following a given function.

4. A machine according to Claim 3, in which the rolling elements and the cam rings are mirror symmetrical with respect to a radial plane of the shaft.

5. A machine according to Claim 4, in which the cam rings are made up of two mirror symmetrical halves.

6. A machine according to Claim 5, in which the cam rings can be tensioned in axial direction.

7. A machine according to Claim 6, in which the cam rings are spring loaded in axial direction.

8. A machine according to Claim 1, 2 or 3, in which the one cam rings of the pair are identical to, but fitted the other way round from, the other cam rings of the pair and the rolling elements of the one cam rings are arranged offset by 45°
with respect to the other cam rings.

9. A machine according to Claim 1, 2 or 3, in which the vanes of the rotating elements have, in a plane containing the shaft axis, the cross-sectional shape of a square, the one diagonal of which is perpendicular to the shaft axis, and the casing consists of two halves, the parting line of which is the centre plane of the annular space.

10. A machine according to Claim 1, 2 or 3, in which the annular position of the cages is variable with respect to the casing.

11. A machine according to Claim 1, 2 or 3, in which at least parts of the radially outer wall of the annular space are formed by moveable, hollow elements which are provided with seals and which, wherein the contact pressure on the vanes subsides and there is therefore a poorer sealing effect, are pressed back firmly against the vanes by a leakage flow caused thereby.

12. A machine according to Claim 1, 2 or 3, in which the rolling elements are held in the cages with the aid of bearing shells or sliding blocks, which are fixed in the cage with the aid of toothings in such a way that they can execute a rolling movement in one direction.

13. A machine according to Claim 1, in which the rotor of an engine/generator being be rigidly connected to each rotation element, the stator of which engine/generator is connected to the casing.

14. A machine according to Claim 13, in which the engines/generators are disc-rotor engines/generators.