Rotary engine and related method

The rotary piston engine design with tiltable rotors and ventilation channels addresses misalignment and friction issues, ensuring stable operation and high efficiency by allowing rotor tilting and reducing friction through airflow.

EP4772718A1Pending Publication Date: 2026-07-08

Patent Information

Authority / Receiving Office
EP · EP
Patent Type
Applications
Filing Date
2025-01-07
Publication Date
2026-07-08

AI Technical Summary

Technical Problem

Rotary piston engines face issues with rotor misalignment and increased friction due to thermal expansion and varying pressure conditions, leading to reduced efficiency and potential jamming.

Method used

The rotors are mounted with one degree of freedom using ball joints and ventilation channels to maintain a stable, positive-locking mesh, minimizing friction and preventing jamming across varying pressure and speed conditions.

Benefits of technology

This design achieves low friction and stable operation over a wide speed range by allowing rotor tilting and using airflow to minimize contact, thereby enhancing engine efficiency.

✦ Generated by Eureka AI based on patent content.

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Abstract

A rotary piston engine comprises an engine compartment (3) in which two rotors (30) are arranged on separate shafts (10) and driven by working fluid flowing through the engine compartment (3). Each shaft (10) has a ball joint (16) on which the respective rotor (30) is mounted. Each rotor (30) comprises two rotor disks (31, 32) which are mounted on the same shaft (10) and together surround the ball joint (16). A ventilation channel (11) is formed in each shaft (10) through which the engine compartment (3) is connected to an environment outside the engine compartment (3) for ventilating the engine compartment (3).
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Description

TECHNICAL AREA

[0001] The present disclosure relates to a rotary piston engine and a method for operating a rotary piston engine. BACKGROUND

[0002] Known rotary piston engines that originate from the inventor of the present invention are described, for example, in US11255258B2, US11098587B2, EP3144471 B1 and EP3379027A1. Another rotary piston engine is known from DE102007019958A1.

[0003] These rotary piston engines comprise a motor chamber in which two rotors are arranged on separate shafts. The motor chamber has an inlet and an outlet for a working fluid. A working fluid flows through the motor chamber, driving the two rotors. The energy is then transmitted via the shafts. Each rotor has a toothed ring, so that the teeth of the two rotors mesh and rotate together.

[0004] In general, to achieve the highest possible efficiency in a rotary piston engine, friction losses should be kept as low as possible. Preliminary work on the invention revealed that misalignment of the two rotors is problematic in rotary piston engines. The two rotors are coupled by the interlocking gear rings, and at the same time, frictional contact between the rotor faces and the engine compartment wall must be avoided. However, achieving a stable, positive-locking gear connection without jamming is already made difficult by temperature changes and the resulting thermal expansion. Furthermore, the pressure of the working fluid can cause the rotors to tilt, increasing friction or potentially leading to jamming. A rotary piston engine should, however, be able to operate stably and with low friction over a wide speed range and variable pressures.Preliminary work on the invention has shown that in known rotary piston engines, rigid mounting of the rotors on their respective shafts and the effects of variable pressure in the engine compartment are decisive for misalignment and increased friction, resulting in a reduction in efficiency. These problems are overcome by the present invention. SUMMARY

[0005] As a Task The invention can be regarded as providing a rotary piston motor and a method which minimize friction and the risk of rotor jamming and thus provide the highest possible efficiency of the rotary piston motor.

[0006] This task is solved by the rotary piston motor and the method with the features of the independent claims.

[0007] In this invention, rotors are mounted to allow tilting with one degree of freedom, thereby preventing jamming and frictional contact. This degree of freedom is maintained across widely varying pressure conditions—from motor start-up to high rotational speeds during continuous operation—by means of ventilation channels that ventilate or extract air from the motor compartment depending on the pressure conditions or rotational speed. This will be described in more detail later.

[0008] A rotary piston engine according to one embodiment of the invention comprises an engine compartment in which two rotors are arranged on separate shafts. The rotors have interlocking teeth. The engine compartment has an inlet and an outlet for a working fluid, and the rotors are driven by the working fluid. Each shaft has a ball joint on which the respective rotor is mounted. Furthermore, each rotor comprises two rotor disks, which are mounted on the same shaft and together surround the ball joint of the shaft. A ventilation channel is formed in each shaft, through which the engine compartment is connected to an environment outside the engine compartment for ventilating the engine compartment.

[0009] In a method according to the invention, a rotary piston motor of the invention is operated by passing a working fluid through the motor chamber of the rotary piston motor to drive its rotors.

[0010] The ball joint of the shaft allows the rotor to be mounted with one degree of freedom. This means the rotor is not rigidly coupled to the shaft, but can tilt slightly relative to it, unlike the rotary piston motor designs shown in the prior art. This also creates a degree of movement between the two interlocking rotors, which are mounted on different shafts. The ventilation channels maintain the degree of freedom of the flexibly mounted rotors and are essential for a stable, positive-locking mesh without jamming across varying pressure conditions and rotational frequencies.

[0011] The degree of freedom in the bearing of the rotors allows for interlocking without jamming over a wide temperature range and a wide speed range, with a friction-reducing airflow occurring at the end faces of the rotors.

[0012] At the front, the rotors are essentially sealed to the housing wall, but a small air gap remains through which air flows as the motor speed increases. The higher the rotational speed, the more air is drawn in through the ventilation channels. This air forms an air film that minimizes friction at the front faces.

[0013] To prevent the two rotary pistons / rotors, mounted on different shafts, from tilting and stalling when tilted relative to each other, the division of each rotary piston into at least two rotor disks is also relevant. In the axial direction, the rotor is thus formed by two narrower parts, which may have a small gap between them and offer a certain degree of mobility relative to each other, thus counteracting tilting with a rotor disk of the other rotary piston.

[0014] The specific effects of the ventilation ducts in maintaining the rotors' degrees of freedom are described in more detail with reference to exemplary configurations. When the rotary piston engine starts, the ventilation ducts vent the engine compartment; that is, a fluid (a portion of the working fluid) from the working / engine compartment flows out of the engine compartment via the ventilation ducts. As the engine speed increases, the flow direction reverses, so that ambient air is drawn in through the ventilation ducts and flows through the engine compartment together with the working fluid. The working fluid enters the engine compartment through an inlet, flows along the rotors to drive them, and exits the engine compartment through an outlet. As the rotor speed increases, the volume flow from the outlet is greater than the volume flow through the inlet into the engine compartment because the air drawn in via the ventilation ducts is added to the working fluid. Optional designs

[0015] Variants of the rotary piston engine and the method according to the invention are the subject of the dependent claims and are explained in the following description. ventilation duct

[0016] Each shaft incorporates a ventilation channel, creating a fluidic connection between the engine compartment and its surroundings. Depending on the pressure conditions, fluid can flow out of the engine compartment through this ventilation channel, or a fluid (air) can flow into the engine compartment from outside. Except for the ventilation channels and at least one inlet and one outlet for the working fluid, the engine compartment can be airtight.

[0017] The ventilation duct comprises an axial section that runs axially within the shaft and terminates in an axial ventilation opening at one axial end of the shaft. Optionally, the shaft may have an axial ventilation opening at only one axial end, while the opposite axial end has no ventilation opening. The shaft extends out of the engine compartment, and the axial ventilation opening is located outside the engine compartment. This provides a connection to an environment outside the engine. In a variation, the axial end can be closed, and the axial ventilation opening can be replaced by at least one lateral opening located on the shaft outside the engine compartment.

[0018] Each shaft can have ventilation openings on its outer surface (viewed axially within the engine compartment). These outer surface ventilation openings represent the opposite end of the ventilation duct, allowing fluid to flow into the ventilation duct through the outer surface ventilation openings and exit the ventilation duct through the axial ventilation opening, or vice versa. Each outer surface ventilation opening can be connected to the axial section of the ventilation duct via a radial section (radial duct). The radial ducts run radially outwards from the axial section within the shaft. They can run perpendicular to the axial section. Alternatively, the radial ducts can have both a radial and an axial component, thus running at an angle to the axial section.The angle between a radial channel and the axial channel can either be 90° or chosen so that flowing fluid is deflected by less than 90° to reduce flow resistance.

[0019] The ventilation openings on the outer surface of a shaft can generally be arranged at various positions in the axial direction and / or at various positions in the circumferential direction of the shaft. For the most uniform ventilation possible, it can be advantageous to provide ventilation openings at at least two or at least three different positions in the circumferential direction of the shaft. These ventilation openings can be evenly distributed in the circumferential direction; for example, three ventilation openings can be distributed around the shaft at 120° intervals. In the axial direction, ventilation openings can be arranged symmetrically about an axial center (the center of the shaft's ball joint). In particular, ventilation channels can be located at at least two different heights in the axial direction, adjacent to the two rotor disks, especially, viewed in the axial direction of the shaft, above and below the ball joint.Alternatively or additionally, at least one of the ventilation openings can be formed on the ball head, i.e., viewed in the axial direction of the shaft, not above or below the ball head, but on the ball head itself, particularly in the center of the ball head. Preferably, several ventilation openings, e.g., three, are formed on the ball head, evenly distributed in the circumferential direction.

[0020] The exact positions of ventilation openings and their associated effects are explained in more detail below.

[0021] Each rotor can have an upper and a lower base, each perpendicular to a rotor axis of rotation. The rotor bases can be flat and parallel to an adjacent engine compartment wall. A (small) gap is formed between one of the rotor bases and an adjacent engine compartment wall; frictional contact should be avoided. At least one (in particular at least three or exactly three) of the ventilation openings can be located at the gap between one of the rotor bases and the adjacent engine compartment wall, or adjacent to one of the rotor bases and the adjacent engine compartment wall. This arrangement of ventilation openings on the shaft's outer surface can apply equally to the upper and lower bases of the rotor.When the rotor is designed from two adjacent rotor disks, the upper and lower base sides refer to the sides of the two rotor disks that are farther apart, not the sides of the rotor disks that face each other.

[0022] In other words, the axial ends of the rotor can be formed by an upper and a lower base, with ventilation openings located axially adjacent to (or at the level of, or in the region of) the axial ends of the rotor disks. Each of these ventilation openings can also be located axially between one of the axial ends of the rotor and a housing wall (housing base) adjacent to that axial end.

[0023] The ventilation openings described above, located on the upper and lower base of the rotor, create an air film between the base and an adjacent housing wall (or a sealing plate on the housing wall, described in more detail later). When the motor starts and pressure builds up on the rotors, working fluid flows along the base and partially exits the motor compartment via the air channels. This results in a more uniform pressure across the base and prevents the rotors from tilting. It also prevents the formation of unwanted pressure cushions. At higher speeds, the incoming air creates an air film that minimizes frictional contact on the rotor bases and, in the case of the sealing plates described later, prevents them from bending, thus avoiding friction and damage to the sealing plates. Sealing plates and arrangement of ventilation openings of the shafts next to the sealing plates

[0024] The motor compartment can be bounded by two opposing (especially parallel) housing bases. These housing bases are parallel to the bases of the rotors and thus perpendicular to the respective rotor axes of rotation. A sealing plate can be arranged between the bases (end faces) of the rotors and the adjacent housing base. A sealing plate can cover essentially the entire housing base. In particular, a sealing plate can have two openings through which the two shafts of the two rotors extend. Furthermore, the sealing plate can cover the entire area of ​​the bases of the two rotors.

[0025] At least some of the ventilation openings can be located adjacent to the sealing plate, in particular directly next to the sealing plate or axially at the same level as the sealing plate. For two sealing plates, ventilation openings can therefore be arranged axially at two different heights, adjacent to one of the sealing plates each.

[0026] Compressed air or the working fluid, which could flow behind the end-face sealing plates, can enter the ventilation duct through the ventilation openings and thus escape, keeping the sealing plates in position and preventing the rotors from becoming jammed. A ventilation groove on the sealing plate, which will be described in more detail later, also contributes to this.

[0027] The seal (sealing plate) initially rests on the rotor's end faces. At higher speeds, the Venturi effect, or a negative pressure, draws air in through the ventilation channels. This drawn-in air creates an airflow across the sealing plate, preventing contact between the rotor's end face and the sealing plate.

[0028] As the rotational speed increases, the venting becomes ventilation. This allows air to be drawn in through the axial ventilation openings as the rotor speed increases, flowing between the sealing plates and the adjacent base surfaces of the rotors. Consequently, as the rotor speed increases, there is no contact between the base surfaces of the rotors and the sealing plates. Due to the diffuser effect, the sealing plates are pushed outwards by the flowing air and rest on the resulting cushion of incoming air at the rotor ends.

[0029] Each sealing plate can include two openings through which the shafts of the two rotors extend. The two openings can each be circular with an additional venting groove, or circular with a venting groove. One diameter of the circular opening corresponds to one diameter of the shafts. The venting groove provides an air channel along the shaft between opposite sides of the sealing plate. This design prevents compressed air / working fluid from accumulating behind the sealing plate, allowing it to escape via the venting groove and subsequently through the ventilation channels.

[0030] Optionally or additionally, the sealing plate can have an annular recess at or around each of the two openings, whereby one or more ventilation openings of the shaft can be located directly next to the annular recess or are fluidically connected to the area of ​​the annular recess via vent grooves in the sealing plate. The recess is formed on the side of the sealing plate facing the housing wall. Shaft with ball head and associated rotor consisting of two rotor discs

[0031] Each shaft has a ball joint on which the respective rotor is mounted. A ball joint forms an approximately spherical thickening of the shaft. In a cross-section along the shaft's longitudinal axis, the shaft therefore does not have a constant width, but rather a maximum width at the center of the ball joint. In cross-section, the shaft has a circular segment or a rounded shape. This allows a rotor mounted on the shaft to tilt slightly relative to its longitudinal axis.

[0032] Each rotor comprises at least two rotor disks (rotor parts) which are mounted side by side axially on the same shaft and together surround the ball head. Preferably, exactly two rotor disks (rotor halves) form a rotor, since with more than two axially adjacent rotor disks the design would be more complex and, in principle, rather disadvantageous.

[0033] The two rotor disks that form a rotor can each have a pan-shaped (spherical segment-shaped) depression on their facing sides. These pan-shaped depressions rest on the ball head and are shaped accordingly. An axial opening is formed in the center of each pan-shaped depression, through which the shaft extends. The two rotor disks can each extend axially to the center of the ball head and can have the same thickness (that is, the same extent along the longitudinal axis of the shaft). Power transmission between rotor discs and shaft, with ventilation.

[0034] Power transmission elements can be present for power transmission between the rotor disks and the associated shaft. Each power transmission element can extend from a receptacle in the shaft (or in the ball joint of the shaft) to a receiving groove in the rotor disks. Each power transmission element can thus be inserted into a receptacle in the shaft and extend radially outward from the receptacle into a receiving groove of a rotor disk. Due to the two-part rotor design consisting of two rotor disks, each with its own receiving groove, a power transmission element can extend into the two mutually aligned receiving grooves of the two rotor disks.

[0035] The shaft's receptacles are recesses, such as milled slots, into which the power transmission elements can be inserted. These receptacles are located at least within the ball joint and can extend beyond the ball joint in the axial direction of the shaft, meaning they may be longer than the rounded part of the ball joint.

[0036] The receiving grooves of the rotor disks are notches on the inside of the rotor disk, i.e., at a central opening through which the shaft protrudes.

[0037] The longitudinal direction of the receiving grooves runs in the axial direction of the shaft or at least has a directional component in the axial direction. The depth of the receiving grooves is measured in the radial direction.

[0038] The power transmission elements can optionally be held with play in the mounting grooves of the rotor disks and / or the shaft receptacles to improve mobility between the rotor disks and the associated shaft. This play prevents the power transmission elements from being clamped in both the mounting grooves and the receptacles; in particular, there is no interference fit between the mounting grooves and the receptacles. Rather, a small gap remains circumferentially between the power transmission elements and a wall of the mounting grooves and / or the receptacles. It is possible to provide for the power transmission elements to be rigidly fixed to the shaft or held without play, while allowing play in the rotor disk receptacles.

[0039] Each or at least some of the shaft's mounting points can incorporate one of the ventilation openings of the ventilation channel. Viewed circumferentially along the shaft, the ventilation openings are precisely positioned to coincide with the mounting points. This ensures proper ventilation even in the areas surrounding the power transmission elements. An unwanted pressure buildup in these areas is thus avoided, particularly during motor start-up, thereby preventing jamming.

[0040] Each power transmission element can have a ventilation opening, which is positioned to match the ventilation opening of the shaft's ventilation channel. The ventilation opening extends radially outwards with respect to the shaft and serves to vent the spherical area, i.e., the area between the spherical head and the rotor discs.

[0041] Shape of the power transmission elements: Each power transmission element can be formed by an elongated body whose longitudinal axis is aligned with the axial direction of the shaft. The elongated body can have a widening in the middle of its longitudinal direction. The ventilation opening is formed in the area of ​​this widening. The receptacle on the ball joint also has a widening in the axial direction, so that the widening holds the power transmission element axially within the receptacle on the ball joint, preventing it from axially exiting the receptacle on the ball joint. In the assembled state, the widening of the power transmission element lies completely within the ball joint.Because the widening of the power transmission element does not protrude radially from the ball head, when assembling the motor the power transmission elements can first be inserted radially into the receptacles on the ball head and then the rotor discs can be placed axially onto the ball head. Rotor suspension for flexibility between the rotor halves

[0042] Each rotor can have at least one spring element between its rotor disks to provide one degree of freedom between the disks. The spring element is clamped between the disks and thus held in position. An elastic, deformable material is used for the spring element, for example, silicone or a rubber material. The spring element can be formed as a ring surrounding the shaft. A ring is understood to be a closed shape, which need not be circular but can, for example, be cloverleaf-shaped. This shape of the spring element can be chosen depending on the cross-sectional shape of the rotor disks, which can, for example, have several recesses into which the working teeth of the other rotor engage. In a cross-section, the spring element can be rounded, particularly circular, or have flat surfaces facing the two rotor disks.

[0043] The rotor discs that form a rotor can each have a receiving groove for the spring element on their facing sides. The receiving groove can be shaped to fit the spring element. The thickness of the spring element (i.e., its extension in the longitudinal direction of the shaft) is greater than the sum of the depths of the two receiving grooves on the two rotor discs, so that the two rotor discs are (slightly) separated from each other by the spring element. The spring element also acts as a seal between the rotor discs, but the flexibility provided by the spring element between the rotor discs plays a crucial role in maintaining the degree of freedom between the rotor discs and compensating for horizontal movements. A rigid connection between the rotor halves is avoided. A rotor disc on one shaft can be toothed with the rotor disc on the other shaft and should be able to tilt to accommodate this toothing.The degree of freedom provided by the spring element allows one rotor disk to tilt without requiring the other rotor disk on the same shaft to tilt rigidly in the same way. Ultimately, this results in optimal sealing without jamming. Since the spring element creates some play between the rotor halves, frictional contact between the rotor bases and the housing wall or the seal on the housing wall is better prevented. External shape of the rotors

[0044] The rotors can have radially projecting working teeth against which the working fluid presses as it flows through the motor chamber, thus driving the rotors. Each rotor can, for example, have two or three working teeth evenly distributed around its circumference. The rotors also have recesses into which the working teeth of the other rotor engage. The rotor disks, which together form a rotor, collectively constitute the working teeth and recesses.

[0045] Optionally, each rotor working tooth can have a receiving slot in which a sealing strip is arranged. The sealing strips extend radially outward from the working teeth to create a seal against the motor housing.

[0046] Each receiving slot can open radially inwards into a cylindrical bore, the diameter of which is larger than the width of the adjacent receiving slot. A cylindrical bore can be understood as a hole with a longitudinal axis parallel to the longitudinal axis of the shaft.

[0047] Each cylinder bore can accommodate a sealing strip spring, whereby the sealing strip received in the receiving slot projects into the cylinder bore and is pressed outwards by the sealing strip spring.

[0048] The sealing strip may have radially inward-projecting locking wings at its axial ends, extending into the cylinder bore. The sealing strip spring is arranged axially between the locking wings, so that the locking wings prevent the sealing strip from axially protruding from the cylinder bore. The locking wings thus seal the cylinder bores, but do not prevent fluid flow.

[0049] Each cylinder bore can accommodate a (non-hollow) silicone thread as a sealing strip spring. The diameter of the silicone thread is larger than the width of the receiving slot, preventing the silicone thread from escaping the cylinder bore and entering the receiving slot.

[0050] Alternatively, a hollow hose can be installed in each cylinder bore to act as a sealing strip spring. The hollow hose is fluidically connected to the engine compartment, so that when pressure builds up in the engine compartment as the rotors start up, pressure also builds up in the hollow hose, forcing the sealing strips outwards. Compressed air thus also flows into the hollow hoses, which press against the sealing strips and, up to a certain rotational speed, provide the force for the sealing effect of the sealing strips. At higher rotational speeds, however, the centrifugal force of the sealing strips takes over the sealing effect. Working fluid and applications of the rotary piston engine

[0051] The working fluid that drives the rotors can, in principle, be any fluid and is selected depending on the engine's application. For example, the working fluid can be (compressed) air, i.e., a gas or gas mixture. The working fluid can also be a vapor, particularly water vapor. It can also consist of exhaust gases / combustion products resulting from the combustion of a fuel. The fuel can be, for example, oil-based, especially a fossil fuel, or based on hydrogen gas or methanol. Fuel can, for example, be burned outside the engine, with the combustion products / gases having increased pressure, and this increased pressure is used to drive the rotors.

[0052] The rotary piston motor can be a compressed air motor. In this case, three power transmission elements (distributed circumferentially in 120° increments) can be arranged on each shaft to transmit power from the rotor disks to the shaft. If, however, the rotary piston motor is a steam engine or part of an internal combustion engine, higher operating pressures may occur, which is why a greater number of power transmission elements are selected, for example, six force transducers on each shaft, distributed circumferentially in 60° increments.

[0053] The rotary piston engine can be part of an ORC process (ORC: Organic Rankine Cycle) in which heat is utilized.

[0054] A motor system can consist of several of the described rotary piston motors, with the working fluid flowing through the rotary piston motors in parallel or series. In a series arrangement, the working fluid first flows through one of the rotary piston motors and then through another. The rotary piston motors flowing through one another thus constitute cascaded motor units.

[0055] In a steam-driven or hydrogen gas combustion system, expansion, and thus volume increase, occurs across optionally several cascaded engine units (expansion units). This design allows for a higher isotropic efficiency. The volume of the engine compartment (and therefore the volume available for the working fluid around the rotors) can increase from one rotary piston engine to the next in a cascaded configuration. For example, three rotary piston engines used in series can have volumes of 350 cm³, 660 cm³, and 967 cm³. This accounts for the fact that the volume of the working fluid increases with each engine unit due to expansion.

[0056] In a hydrogen engine design, an external flywheel is unnecessary; the rotors themselves act as the flywheel. Ignition and combustion of hydrogen gas do not occur in the engine compartment where the rotors are located, but rather beforehand in, for example, a specially added pre-chamber or in a rail attached to the engine. Several rotary piston motors can be optionally connected to the rail in a switchable manner: For high power / torque, several (e.g., three) rotary piston motors can be used in parallel, with a direct connection from the rail to each of these motors. Alternatively, a connection from the rail to one or more of the rotary piston motors can be closed, and a switchable connection from one of the rotary piston motors to another can be opened. This allows one of the rotary piston motors to be used either in parallel or in series with another of the rotary piston motors.It is therefore possible to switch between a particularly high efficiency in series operation or (e.g. with an increased combustion rate of a fuel such as hydrogen gas) a higher power output in parallel operation. General characteristics

[0057] In this context, "air" can refer to any gas mixture, any gas, or even a mixture with a liquid or vapor. In particular, air flowing into the engine compartment via ventilation ducts can be ambient air as it exists outside the engine compartment. However, the air flowing in through the ventilation ducts can also be pretreated, for example, by adding engine-conditioning substances, filtering (blocking) harmful particles, and / or adding or removing elements, thereby making the composition of the incoming air more similar to that of the engine fluid.

[0058] For faster understanding, the term "ventilation channel" is used, whereby in principle any fluid can flow through this channel; in particular, the working fluid can flow out or an ambient fluid located outside the engine compartment can flow in.

[0059] In principle, variations of the described designs are also possible, which may achieve the described advantages or effects only to a lesser extent. For example, a ventilation channel should be formed in each shaft, whereby a certain degree of ventilation of the engine compartment is already achieved if at least one ventilation channel is formed in at least one of the shafts. A somewhat improved efficiency compared to the prior art can, in principle, be achieved with variations that only incorporate the design with a ball joint or the ventilation channels.

[0060] In this context, a shaft is understood to be a shaft coupled to a rotor, which rotates when the rotor turns. Rotational energy from the rotary piston motor can be output via the shaft. The shaft can be connected to other components for power output in any known and arbitrary manner.

[0061] An axial direction is understood to be a direction parallel to the longitudinal axis of the shaft(s) or parallel to the axis of rotation of the shafts or rotors. A radial direction is a direction perpendicular to this, extending radially outward from the shaft or vice versa. Descriptions of components with reference to the axial or radial direction refer to the respective shaft unless otherwise specified.

[0062] Properties described in the singular are intended to cover the variants "exactly one" as well as "at least one". For example, the engine compartment can have one or more inlets and / or one or more outlets.

[0063] Variations of the described variants incorporate additional components. For example, instead of the two described rotor discs, four rotor discs can form a single rotor. This also achieves the desired degree of freedom between the rotor discs, but the overall structure and the seal become more complex. A spring element, as described, is used between adjacent rotor discs.

[0064] The additional device features described in the invention also result in variants of the inventive method when used as intended. Conversely, the device can also be configured to carry out the described method variants. BRIEF DESCRIPTION OF THE FIGURES

[0065] Exemplary embodiments are described below with reference to the figures. Identical and similarly functioning components are generally identified by the same reference numerals. FIG. 1 is a schematic perspective view of a rotary piston engine of an embodiment of the invention; FIG. 2 shows components of a rotor with associated shaft of the rotary piston engine; FIG. 3 is an exploded view of the rotor with associated shaft; FIG. 4 shows the rotor with associated shaft in a section along the longitudinal axis of the shaft; FIG. 5 shows its side top view of the shaft; FIG. 6 shows a perspective view of the shaft with one of the associated sealing strips; FIG. 7 shows a sealing plate of the rotary piston engine; FIG. 8 shows parts of the rotary piston engine in a section along the longitudinal axis of one of the shafts; FIG. 9 is a photograph of the opened engine housing of a rotary piston engine of an embodiment of the invention; and FIG. 10 shows a perspective view of the rotary piston engine with the engine housing closed. DETAILED DESCRIPTION OF EXAMPLES OF EXECUTION

[0066] With reference to FIG. 1First, predominantly more general properties of a rotary piston engine according to the invention are described, while most of the differences compared to known rotary piston engines are subsequently explained with reference to the further figures. FIG. 1

[0067] An embodiment of a rotary piston motor according to the invention is shown schematically in FIG. 1 shown. The rotary piston engine 1 comprises a housing (engine housing) 2, which surrounds an engine compartment 3. In FIG. 1 The engine compartment housing 2 is shown without a final top part / cover, so that the engine compartment 3 with the components contained therein is visible.

[0068] The engine compartment 3 has an inlet 4 for the working fluid and an outlet 5 for the working fluid. Furthermore, two rotors 30 are arranged on separate shafts 10 in the engine compartment 3. Each rotor 30 has a toothed ring or teeth 39 on its outer surface, which mesh with the teeth 39 of the other rotor 30, so that the rotors 30 rotate together (in opposite directions) and no working fluid can pass between the two rotors 30.

[0069] The inlet 4 and outlet 5 are arranged such that the working fluid can only reach the outlet 5 from the inlet 4 if, as it flows through the engine compartment 3, it sets the two rotors 30 in rotation. For this purpose, the rotors 30 have radially projecting working teeth 40 on their outer surface. Therefore, as the working fluid flows through the engine compartment, it presses against the working teeth 40 and thus rotates the two rotors 30. Each working tooth 40 has a sealing strip 20 embedded within it, which projects radially from the working tooth 40 to a wall of the engine compartment housing 2. The two rotors 30 each have recesses 41 on their outer surface into which the working teeth 40 of the respective other rotor 30 can engage to form a seal. Each sealing strip 20 is pressed radially outwards by an associated sealing strip spring 23, which will be described in more detail later.

[0070] The term "radial" is understood here in relation to an axis of rotation or the shafts 10. For example, radially projecting working teeth 40 of the rotors 30 are understood to mean that the working teeth 40 project radially outwards with respect to the axis of rotation or the respective shaft 10. Similarly, "axial" is understood to mean a direction parallel to the axis of rotation or to the longitudinal direction of the shafts 10. The two shafts 10 are mounted parallel to each other.

[0071] Power transmission elements 26 are provided for power transmission between rotors 30 and the associated shaft 10. Several power transmission elements 26 project radially from the circumference of each shaft 10 and extend into the respective rotor 30. This ensures that the rotors 30 rotate only together with their respective shaft 10. However, unlike conventional rotary piston engines, the power transmission elements 26 allow for a certain degree of play between one of the rotors 30 and its associated shaft 10, which will be described in more detail later.

[0072] In contrast to conventional rotary piston engines, a ventilation channel 11 is formed within each shaft 10. The ventilation channel 11 allows for the supply or exhaust of air to the engine compartment 3, which will be explained in more detail later.

[0073] A sealing plate 60 can be arranged between an end face of the rotors 30 and a base face of the engine housing 2 that is parallel to it. The sealing plate 60 separates the end face of the rotors 30 from the flat base face of the engine housing 2. An end face of the rotors 30 is understood to be a side that is perpendicular to the axis of rotation of the rotors 30 and thus also essentially perpendicular to the outer surface of the rotors 30. In the example shown, the sealing plate 60 is partially visible below the rotors 30. A similar sealing plate can be added above the rotors 30 in the assembled state, forming a cover for the engine compartment.

[0074] Next, the construction of a rotor 30 will be described in more detail with reference to the following figures. FIG. 2 and 3

[0075] FIG. 2Figure 1 shows components of a rotor 30 with its associated shaft 10. The rotor 30 and shaft 10 are shown in an exploded view. FIG. 3 depicted.

[0076] Both rotors 30 of the rotary piston engine can be formed in the same way.

[0077] The design according to the invention achieves particularly low-friction operation of the rotors 30, thereby preventing tilting between the rotors 30 or rubbing contacts with the sealing plates on the base sides of the engine housing. This is achieved through a two-part design of the rotor 30 with movable bearings on a specially shaped shaft 10, as well as the ventilation of the engine compartment via ventilation channels.

[0078] As in FIG. 3 As shown, the rotor 30 comprises two rotor disks 31, 32, which are mounted on the same shaft 10. For better visibility of the structure, in FIG. 2Only one of the two rotor disks 31, 32 is shown. In an axial section of the shaft 10, in which the rotor disks 31, 32 are held, a surface of the shaft 10 is not straight, in particular not parallel to the axis of rotation of the shaft 10, but convex or rounded and thus thickened. Thus, the shaft 10 forms a spherical head 16 on which the rotor disks 31, 32 are mounted.

[0079] The two rotor disks 31, 32 each have a central bore 34 or axial opening through which the shaft 10 protrudes. How best to FIG. 3As can be seen, the inner surface of each rotor disk 31, 32, which defines the bore 34, is shaped to match the rounded form of the ball head 16. The inner surface of the rotor disks 31, 32 is therefore not straight or parallel to the axis of rotation, but has a concave shape. This forms a cup-shaped depression 34 or spherical socket, analogous to the shape of the ball head 16. Due to this shape, the diameter of the bore 34 of a rotor disk 31, 32 varies. The diameter of the bore 34 increases monotonically in the axial direction towards the other rotor disk 32, 31.

[0080] Due to the mounting of the rotor disks 31, 32 on the ball joint 16 of the shaft 10, the rotor disks 31, 32 can move slightly relative to the shaft 10, in particular tilt. This is important, among other things, to prevent the motor from jamming and stalling when the gear rings of different rotors mesh. Since the gear rings mesh tightly, contact is necessary. At the same time, a certain degree of tilting of the rotors (generally undesirable in the prior art) can never be completely avoided, even with conventional rotors rigidly connected to the shaft. However, if tilted, the tightly meshing gear rings can easily jam or collide with a housing wall / sealing plate.To counteract this, the two-part rotor design is relevant, as it reduces the radial dimension of each rotor disk to half that of a one-piece rotor, thus advantageously reducing the deflection length at a given tilt angle. It is also important that the two rotor disks 31, 32 are not rigidly coupled to each other, but rather that movement between them is possible. This is achieved using a rotor spring, i.e., a spring element 50 made of, for example, silicone or another deformable material. The spring element 50 is located between the two rotor disks 31, 32, which together form a rotor 30. When one of the rotor disks 31, 32 tilts or moves, the spring element 50 is deformed without the other rotor disk 32, 31 having to tilt or move identically. The spring element 50 can be formed in a ring shape around the shaft 10.The term "ring-shaped" means that the spring element 50 forms a closed shape around the shaft 10, although it does not necessarily have to have a circular cross-section perpendicular to the rotor's axis of rotation. In the example shown, it is more in the shape of a four-leaf clover, where the number of leaves or radially outwardly projecting areas of the spring element 50 can be equal to the number of working teeth 40 plus the associated recesses 41. This deviation from a circular shape increases the stability and positional accuracy of the spring element 50. As shown in... FIG. 3As shown, each rotor disk 31, 32 can have a receiving groove 38 for the spring element 50 on its end face, which faces the other rotor disk. The shape of the receiving groove 38 corresponds to the shape of the spring element 50. The diameter of the spring element 50 (i.e., its dimension in the axial direction of the shaft 10) is slightly larger than the sum of the depths of the receiving grooves 38 of both rotor disks 31, 32 (i.e., the dimensions of the receiving grooves 38 in the axial direction of the shaft 10), so that a sealing contact between the rotor disks 31, 32 is achieved by the spring element 50, and a certain degree of movement between the rotor disks 31, 32 is possible while the sealing contact continues to exist.

[0081] Power is transmitted between the rotor disks 31, 32 and the shaft 10 via power transmission elements 26. The shaft 10 has receptacles / recesses 17 on its outer surface, with one of the power transmission elements 26 being inserted into each receptacle 17. The power transmission elements 26 project radially, at least partially, out of the receptacles 17 and into corresponding receiving grooves (notches) 36 in the rotor disks 31, 32. The receiving grooves 36 are formed in the cup-shaped recesses 35 of the rotor disks 31, 32.

[0082] The receiving grooves 36 can extend axially over the entire length of both rotor disks 31, 32, as shown (or alternatively, at least over the entire length of one of the rotor disks 31, 32 and from there into the other rotor disk). This allows the power transmission elements 26 to be inserted into the receptacles 17 of the shaft 10 during motor assembly (with the insertion direction being radial), and then the two rotor disks 31, 32 can be slid axially onto the shaft 10. The two rotor disks 31, 32 are slid onto the shaft 10 from opposite axial ends, and a rotational position of the rotor disks 31, 32 is selected such that the portion of the power transmission elements 26 protruding from the shaft 10 is pushed axially into the receiving grooves 36.

[0083] The FIG. 2 and 3Figure 1 also shows how the sealing strips 20 are held on the rotor disks 31 and 32. Each working tooth 40 of the rotor disks 31 and 32 has a receiving slot 42, which extends radially and axially in the working tooth 40 in a blade-like shape. A sealing strip 20 has a plate or blade shape and is inserted into the receiving slot 42 of the rotor disk 31 and the corresponding receiving slot 42 of the rotor disk 32. To prevent the sealing strip 20 from protruding radially from the receiving slot 42, the sealing strip 20 has a sealing strip hole 21 into which a locking element 22 is inserted. The locking element 22 projects perpendicularly from the plane defined by the plate-shaped sealing strip 20 (this plane of the sealing strip 20 extends radially and axially). The receiving slot 42 has a radial widening in its center to accommodate the locking element 22.To assemble the engine, first the [part] is [part]. FIG. 2 The situation shown is created in which first one of the rotor disks (here rotor disk 31) is placed on the shaft 10 and the sealing strip 20, together with the associated locking element 22, is inserted into the receiving slot 42 of rotor disk 31 (in the axial direction). Then the second rotor disk 32 is pushed onto the shaft, and in this process the locking element 22 is enclosed in the receiving slots 42 of both rotor disks 31 and 32.

[0084] Each receiving slot 42 opens radially into a cylinder bore 43, which is wider than the receiving slot 42. A longitudinal direction of the cylinder bore 43 is parallel to the axial direction of the shaft 10. The cylinder bore 43 preferably extends, as shown, completely through both rotor disks 31, 32 in the axial direction. A sealing strip spring 23 is accommodated in each cylinder bore 43. The sealing strip 20 is dimensioned such that it projects into the cylinder bore 43 and against the sealing strip spring 23. This compresses the sealing strip spring 23 radially and pushes the sealing strip 20 radially outwards. This is, at least at low engine speeds, the decisive force for a sealing effect between the sealing strips 20 and the engine housing.

[0085] How best to FIG. 3Visibly, the sealing strip 20 can project further into the cylinder bore 43 at both ends in the axial direction than in its central area, thereby forming two radially projecting locking wings 24. The locking wings 24 prevent the sealing strip spring 23 from protruding axially from the cylinder bore 43. For this purpose, the sealing strip spring 23 is located, viewed axially, between the two locking wings 24.

[0086] The locking flaps 24 prevent the sealing strip spring 23 from axially protruding from the cylinder bore 43, but do not seal the cylinder bore 43. This allows pressure equalization and a certain fluid flow through the cylinder bore 43. Otherwise, the increasing pressure in the engine compartment would excessively counteract the pressure of the sealing strip spring 23 against the sealing strip 20. This is particularly relevant if the sealing strip spring 23 is designed as a hollow tube. Alternatively, a silicone cord made of solid material or a cord made of another elastically deformable material can be used as the sealing strip spring 23.

[0087] The rotary piston motor of the invention also utilizes a special ventilation system, which is important to avoid undesirable pressure cushions and thus preserve the degree of freedom between the rotors and the rotor disks 31, 32, and to prevent frictional contact on the sealing plates (and also deformation of the sealing plates, which could lead to their destruction). For this purpose, a ventilation channel is used in each shaft. FIG. 2 and 3 Figure 1 shows an axial ventilation opening 12 of the ventilation duct at an axial end of the shaft 10, as well as several radial ventilation openings 13, 14 and 15 on the outer surface of the shaft 10. The ventilation duct is described in more detail with reference to the following figures. FIGS. 4 to 6

[0088] FIG. 4 Figure 1 shows a cross-section through a rotor 30 with associated shaft 10. The cross-section is a section taken centrally along the longitudinal axis of the shaft 10. FIG. 5shows a related side view and FIG. 6 A perspective view. For better visibility of the ventilation openings, the FIGS. 5 and 6 Rotor 30 is not shown.

[0089] How best to FIG. 4 As can be seen, the shaft 10 has an axial bore which forms an axial channel / section 12A of the ventilation channel 11. The ventilation channel 10 extends from an axial end of the shaft 10, where an axial opening / ventilation opening 12 is formed. The axial section 12A can optionally terminate as a blind hole within the shaft 10 or alternatively extend continuously to the opposite axial end of the shaft 10 and form an axial opening there.

[0090] Important are the radial ventilation openings 13, 14, 15, which are formed on the outer surface of the shaft 10. The outer surface is understood to be the outside of the shaft 10 that is not either of the two axial ends. The radial ventilation openings 13, 14, 15 are connected to the axial section 12A by radial channels / radial sections 13A, 14A, 15A of the ventilation duct 11. In the example shown, the radial sections 13A, 14A, 15A extend radially outwards from the axial section 12A. Alternatively, the radial sections 13A, 14A, 15A can also have an axial component and thus run not perpendicularly, but obliquely to the axial section 12A.

[0091] The radial ventilation openings 13, 14 and 15 are located at different positions in the axial direction. In the sectional view of FIG. 4Only one radial ventilation opening 13, one radial ventilation opening 14, and one radial ventilation opening 15 are visible. However, there are several radial ventilation openings 13, 14, and 15 distributed around the circumference of the shaft 10, for example, three of each.

[0092] The radial ventilation openings 15 are located centrally in the axial direction, that is, centrally at the ball head 16 of the shaft 10. The radial ventilation openings 13 are located on or next to an upper base 32A of the rotor 30, which is a base / end face of the rotor disk 32 facing the housing wall (not the other rotor disk 31). Similarly, the radial ventilation openings 14 are located on or next to a lower base 31A of the rotor 30, which is a base / end face of the rotor disk 31 facing the housing wall (not the other rotor disk 32).

[0093] The radial ventilation openings 13-15 serve to ventilate areas of the engine compartment, whereby an airflow in FIG. 4 illustrated with dashed lines. The radial ventilation openings 15 lead to the area between the rotor halves, that is, between the rotor disks 31 and 32. As shown in FIG. 4As shown, each power transmission element 26 can have a corresponding ventilation opening 27, that is, a hole that extends radially (with respect to the shaft 10) through the power transmission element 26. The radial ventilation openings 15 promote pressure equalization in the area between the rotor disks 31 and 32 with respect to the rest of the engine compartment. Otherwise, undesirable pressure conditions could counteract the movement of the rotor disks 31 and 32 relative to each other. For example, if rotor disk 31 is tilted or displaced relative to the other rotor disk 32, an area between the rotor disks 31, 32 (especially at the power transmission element 26 and adjacent to the spring element 50) would be enlarged or reduced, thus compressing or expanding the fluid located there. The resulting pressure differences can be relieved via the radial ventilation channels.

[0094] The radial ventilation openings 13-15 also have additional effects: When the engine starts (and at relatively low speeds), the pressure in the engine compartment rises. Working fluid can escape the engine compartment through the radial ventilation openings 13-15, thus counteracting unwanted pressure differences that could lead to misalignment of the rotors 30 or excessive friction between the rotors 30 and the sealing plates 60. Otherwise, the working fluid could force the rotors apart during engine start-up and cause a leak. As the engine speed increases, the flow velocity of the working fluid in the engine compartment rises, and the flow direction reverses in the ventilation duct 11. Working fluid no longer leaves the engine compartment through the ventilation duct 11; instead, a fluid (e.g., ambient air) flows into the engine compartment through the ventilation duct 11.In continuous operation of the rotary piston engine with compressed air as the working fluid, an example ratio of approximately 82:69 was measured between compressed air flowing out through the outlet and compressed air flowing in through the inlet.

[0095] The air flowing in through the ventilation ducts forms, in particular, a low-friction air film between the rotor 30 and the sealing plates on the engine housing. The flow at the sealing plates and the structure of the sealing plate are further described with reference to the following figures. FIGS. 7 to 9

[0096] FIG. 7 schematically shows a perspective view of a sealing plate 60. FIG. 8 is a cross-section of a section of the rotary piston motor 1 and shows the positioning of the sealing plates 60. FIG. 9 Figure 2 is a photograph of the opened engine compartment housing 2 and shows one of the sealing plates 60 on a base side (housing base surface) of the engine compartment. FIG. 9Graphically, the metallic engine compartment housing 2 differs from the darker material of the elastically deformable sealing plate 60. FIG. 7 and 8 They are schematic for better visibility of components, meaning that size ratios and gaps between components do not necessarily correspond to concrete implementations.

[0097] How best to FIG. 7As can be seen, the sealing plate 60 comprises two openings 61 through which the two shafts 10 extend in the assembled state. The openings 61 can be essentially circular. However, the circular shape is interrupted by one or more vent grooves 65, in the illustrated example three vent grooves 65. The vent grooves 65 radially enlarge the opening 61. In the assembled state, the vent groove 65 provides a fluidic connection between an end face 62 of the sealing plate 60, which faces the rotors 30, and an opposite rear face 63 of the sealing plate 60, which faces the engine housing, i.e., the housing base surfaces 6 and 7, see in particular FIG. 8Depending on the rotational position of the shaft 10, the vent groove 65 is directly adjacent to the vent opening 13 or 14 and is fluidically connected to it. Furthermore, an annular recess 64 is formed around the opening 61 on the rear side 63 of the sealing plate 60. In the area of ​​the annular recess 64, the opening 61 thus has a larger diameter than over its remaining axial area. The annular recess 64 therefore forms an annular free area. Any fluid located behind the sealing plate 60 can escape through this area and then exit the engine compartment via the vent groove 65 and the radial vent openings 13 or 14 (at low engine speeds).

[0098] The vent grooves 65 of the sealing plate 60 are important to allow any (working) fluid that might be located between the sealing plate 60 and the engine housing 2 to escape. In particular, the sealing plate 60 can be pressed against the engine housing 2 without air pockets / fluid cushions forming between the sealing plate 60 and the engine housing 2, since the fluid can escape via the vent grooves 65. This prevents deformation of the sealing plate 60, which could lead to a collision with one of the rotors 30.

[0099] In the case of compressed air as the working fluid, the compressed air flowing into the engine compartment acts not only on the rotors 30, but also on the end faces of the sealing plates 60, which offer a very large surface area. Without vent grooves 65, this can lead to deformation; that is, the sealing plates 60 bend and jam the rotors 30, causing the engine to start poorly or not at all. Furthermore, the sealing plates 60 can be destroyed. The vent grooves 65 allow the compressed air to pass through them when the engine is started and be expelled via small channels. This creates a pressure equalization before the rotors 30 begin to rotate, preventing the sealing plates 60 from bending. As the rotational speed of the rotors 30 increases, a vacuum is created, which draws air from the outside into the working chamber through the vent grooves 65.This creates an air cushion between the front face 62 and the rotors 30, so that there is no contact between the rotor end faces and the sealing plate 60.

[0100] The ventilation channels and the two-part rotor design prevent friction, tilting and jamming, resulting in particularly high efficiency with minimal wear. FIG. 10

[0101] For the sake of completeness, in FIG. 10 A rotary piston engine with a closed engine housing is shown schematically. The inlet 4 for working fluid is visible. It is also shown that the axial ventilation openings 12 of the two shafts 10 lead to the surroundings of the rotary piston engine, allowing ambient air to enter through the axial ventilation openings 12.

[0102] Rotary piston motors of the type described can be used for various applications and with different working fluids. For example, in the upper section of FIG. 10 (and in the lower range of FIG. 1 A shaft is shown which serves as a variable transmission and to which loads can be connected. Alternatively, loads can also be connected directly to the rotor shafts.

[0103] The properties described for the various figures can be combined with one another. The described embodiments are purely illustrative, and modifications thereof are possible within the scope of the attached claims. Reference symbol list

[0104] 1 Rotary piston motor 2 Engine housing 3 Engine compartment 4 Inlet for working fluid 5 Outlet for working fluid 6, 7 Opposing housing bases defining the engine compartment 3 10 Shaft of a rotor 30 11 Ventilation channel in the shaft 10 12A Axial section of the ventilation channel 11 12 Axial ventilation opening of the shaft 13, 14, 15 Radial ventilation openings for ventilation of areas of the engine compartment 13A, 14A, 15A Radial sections of the ventilation channel 11 16 Ball head of the shaft 17 Recess / milling for the power transmission element (and provided with ventilation opening 15 for ventilation of the ball area) 20 Sealing strip 21 Sealing strip hole for locking element 22 22 Locking element for the sealing strip 23 Sealing strip spring (round cord, Solid silicone material) 24 Radially projecting sealing wings of the sealing strip 20 26 Power transmission elements 27 Ventilation passage of the power transmission elements 26 30 Rotors, each formed by two rotor disks 31, 32 31,32 Rotor discs of the two-part rotor 31A Lower base of the rotor / end face of the rotor disc 31 towards the housing wall 32A Upper base of the rotor / end face of the rotor disc 32 towards the housing wall 34 Bore / opening of the rotors or rotor discs for the shaft 35 Ball socket / cup-shaped recess of the rotor disc 31, 32 36 Receipt grooves in the rotor discs for the power transmission elements 26 38 Receipt groove in the rotor discs 31, 32 for the rotor suspension 50 39 Teeth of the rotor discs 31, 32 40 Working teeth of the rotors 30 41 Recesses of one rotor for engagement of the working teeth of the other rotor 42 Receipt slot in the working tooth 40 for receiving the sealing strip 20 43 Cylindrical bore for receiving the sealing strip suspension 23 50 Rotor suspension / spring element 60 Sealing plate 61 Openings in the sealing plate for the shafts 62 Front side of the sealing plate facing the rotors 63 Back side of the sealing plate,which rests against the engine compartment housing; 64 ring-shaped recess on the front face of the sealing plate; 65 ventilation grooves at the openings of the sealing plate.

Claims

1. A rotary piston engine comprising: a motor chamber (3) in which two rotors (30) are arranged on a respective shaft (10), wherein the rotors (30) have interlocking teeth (39), wherein the motor chamber (3) has an inlet (4) and an outlet (5) for a working fluid and the rotors (30) are driveable by the working fluid, characterized by that Each shaft (10) has a ball head (16) on which the respective rotor (30) is mounted, that Each rotor (30) has two rotor disks (31, 32) which are mounted on the same shaft (10) and together surround the ball head (16), wherein a ventilation duct (11) is formed in each shaft (10), through which the engine compartment (3) is connected to an environment outside the engine compartment (3) for ventilating or extracting the engine compartment (3).

2. The rotary piston engine according to the immediately preceding claim, wherein the ventilation duct (11) comprises an axial section (12A) which extends axially inside the shaft (10) and reaches to an axial ventilation opening (12) of the shaft (10), wherein the shaft (10) extends out of the engine compartment (3) and the axial ventilation opening (12) is located outside the engine compartment (3).

3. The rotary piston motor according to the immediately preceding claim, wherein each shaft (10) has ventilation openings (13-15) on its outer surface which are connected to the axial section (12A) via radial sections (13A-15A) of the ventilation channel (11), wherein at least one of the ventilation openings (15) is formed in the ball head (16).

4. The rotary piston motor according to claim 2 or 3, wherein axial ends of the rotor (30) are formed by an upper and a lower base (31A, 32A), wherein at least several of the ventilation openings (13, 14) are located next to the axial ends of the rotor (30) when viewed in the axial direction.

5. The rotary piston engine according to the immediately preceding claim, wherein the engine compartment (3) is bounded by two opposing housing base surfaces (6, 7), wherein the housing base surfaces (6, 7) are parallel to base sides (31A, 32A) of the rotors (30) and thus perpendicular to a respective axis of rotation of the rotors (30), wherein a respective sealing plate (60) is arranged between the base sides (31A, 32A) of the rotors (30) and the respective adjacent housing base surface (6, 7), wherein at least some of the ventilation openings (13, 14) are located adjacent to the sealing plate (60).

6. The rotary piston motor according to the immediately preceding claim, wherein each sealing plate (60) comprises two openings (61) through which the shafts (10) of the two rotors (30) extend, wherein the two openings (61) are each formed as a circular shape with an additional venting groove (65), wherein a diameter of the circular shape is selected corresponding to a diameter of the shafts (10) and the venting groove (65) provides an air channel along the shaft (10) between opposite sides of the sealing plate (60).

7. The rotary piston motor according to claim 5 or 6, wherein the sealing plate (60) has an annular recess (64) at each of the two openings (61) on a rear side (63) facing away from the rotors (30), wherein one or more of the ventilation openings (13, 14) of the shaft (10) are located next to the annular recess (64).

8. The rotary piston motor according to one of the preceding claims, wherein the rotor disks (31, 32) forming the same rotor (30) each have a pan-shaped recess (35) on their mutually facing sides, which rests on the ball head (16) and is shaped according to the ball head (16); wherein the rotor disks (31, 32) each have an opening (34) in the center of their pan-shaped recesses (35) through which the shaft (10) extends; and wherein the two rotor disks (31, 32) each extend in the axial direction to the center of the ball head (16).

9. The rotary piston motor according to one of the preceding claims, wherein power transmission elements (26) are provided for power transmission between the rotor disks (31, 32) and the shaft (10), wherein each power transmission element (26) extends from a receptacle (17) in the shaft (10) to a receiving groove (36) in the rotor disks (31, 32).

10. The rotary piston motor according to the immediately preceding claim, wherein the power transmission elements (26) are held with clearance in the receiving grooves (36) of the rotor disks (31, 32) and / or the receivings (17) of the shaft (10) in order to maintain mobility between the rotor disks (31, 32) and the associated shaft (10).

11. The rotary piston motor according to claim 9 or 10, wherein in each receptacle (17), within the ball head (16), one of the ventilation openings (15) of the ventilation duct (11) is formed; wherein each power transmission element (26) has a ventilation passage (27) which is arranged to fit the ventilation opening (15) formed in the ball head (16) and extends radially outwards with respect to the shaft (10) in order to vent or aerate an area between the ball head (16) and the rotor disks (31, 32).

12. The rotary piston motor according to one of the preceding claims, wherein each rotor (30) has a spring element (50) between the rotor disks (31, 32) to provide one degree of freedom between the rotor disks (31, 32); wherein the rotor disks (31, 32) have a receiving groove (38) for the spring element (50) on their mutually facing side.

13. The rotary piston motor according to one of the preceding claims, wherein the rotors (30) have radially projecting working teeth (40) against which the working fluid presses as it flows through the motor chamber (3) and thus drives the rotors (30); wherein the rotors (30) have recesses (41) into which the working teeth (40) of the respective other rotor (30) engage; wherein each working tooth (40) of the rotors (30) has a receiving slot (42) in which a sealing strip (20) is arranged, wherein the sealing strips (20) extend radially out of the working teeth (40) to provide a seal to a motor chamber housing (2); wherein each receiving slot (42) opens radially inwards into a cylinder bore (43), wherein a sealing strip spring (43) is received in each cylinder bore (43), wherein the sealing strip (20) received in the receiving slot (42) projects into the cylinder bore (43) and is pressed outwards by the sealing strip spring (43);wherein the sealing strip (20) has locking wings (24) projecting radially inwards into the cylinder bore (43), wherein the sealing strip spring (43) is arranged axially between the locking wings (24) so ​​that the locking wings (24) prevent axial protrusion of the sealing strip (20) from the cylinder bore (43).

14. The rotary piston motor according to the immediately preceding claim, wherein the sealing strip suspension (43) is a silicone thread; or wherein the sealing strip suspension (43) is a hollow tube which is fluidically connected to the motor chamber (3), so that when pressure builds up in the motor chamber (3) when the rotors (30) start up, a pressure build-up also occurs in the hollow tube due to inflowing working fluid, which pushes the sealing strips (20) outwards.

15. A method for operating a rotary piston motor according to one of the preceding claims, wherein a working fluid is passed through the rotary piston motor to drive its rotors (30).

16. The method according to the immediately preceding claim, if it depends on one of claims 5-7, wherein, with increasing rotational speed of the rotors (30), air is drawn in through the axial ventilation openings (12) and flows between the sealing plates (60) and the adjacent base faces (31A, 32A) of the rotors (30), so that, with increasing rotational speed of the rotors (30), there is no contact between the base faces (31A, 32A) of the rotors (30) and the sealing plates (60).