ROTARY PISTON ENGINE

Description

[0001] This patent application claims priority from German patent application DE 10 2018 203 992.5, the contents of which are incorporated herein by reference.

[0002] The invention relates to a rotary piston machine, in particular a claw machine, which can be operated, for example, as a compressor, vacuum pump or blower.

[0003] Rotary lobe pumps with interlocking rotary lobes are generally known from the state of the art through obvious prior use.

[0004] US 2016040669 A1 discloses a twin-shaft rotary lobe pump capable of improving reliability and operating efficiency by preventing exhaust gas from flowing back into a pump as much as possible, preventing the interior of the pump from being overcompressed as much as possible, and suppressing the temperature rise within the pump. Also described are twin-shaft rotary pumps in which two rotating shafts with rotors are supported by bearings such that, on the one hand, the two rotors rotate in a non-contact manner with a small clearance between the rotors, and, on the other hand, the two rotors rotate in a non-contact manner with a small clearance between an inner surface of a cylinder and the two rotors.A gas sucked into the cylinder and compressed is discharged from the cylinder, wherein an escape hole is formed in at least one of the end wall portions forming the two ends of the cylinder, which escape hole can allow a part of the compressed gas to escape and opens in the axial direction of the rotating shafts.

[0005] Furthermore, GB 2111126 A describes a pump, e.g., a multi-stage vacuum pump, consisting of a pumping chamber through which a pair of parallel shafts extend. Each shaft carries rotors in tandem, at least two of which are of the Northey or "claw" type. The rotors are arranged on the shafts in cooperating, mating pairs, each pair occupying a separate location in the pumping chamber and separated from the adjacent pair(s) of rotors by a fixed partition. Each "claw" rotor of a pair is mounted on its shaft in reverse orientation to the corresponding "claw" rotor(s) of the adjacent pair(s). The rotors may be of the bilobed Roots type.

[0006] The invention is based on the object of creating an improved rotary piston engine. In particular, it should be particularly powerful, especially with regard to its suction capacity, and extremely durable.

[0007] This object is achieved according to the invention by a rotary piston machine according to claim 1. Advantageous embodiments may have features of dependent claims.

[0008] The core lies in the fact that a ventilation channel is formed in the housing, in particular precisely, which temporarily establishes a flow connection - directly or indirectly - between the working chamber or at least one of the working sub-chambers, in particular the first working sub-chamber, and the environment. The ventilation channel opens into the working chamber via one, in particular precisely one, ventilation channel opening, in particular on the pressure side.

[0009] Preferably, during a compression phase, the ventilation duct is open, allowing air, particularly ambient air at ambient pressure, to enter the working chamber from the outside. If the ventilation duct opening is at least partially open, it is possible to supply air from the outside into the working chamber.

[0010] Further preferably, in an intake phase or in an intake cycle, the ventilation duct or the ventilation duct opening is open, which, depending on an operating point, leads to a relaxation or ventilation of the space in the housing of the rotary piston machine or the gas located therein, which space is then in direct or indirect flow connection with the ventilation duct or the ventilation duct opening or is adjacent to the ventilation duct opening.

[0011] Thermal loads on parts of the rotary piston machine, such as bearings and shaft(s), can be effectively reduced by the introduced air. The introduced air generally has a lower energy level. The performance of the rotary piston machine is thus particularly high. In particular, the temporary introduction of air into the working chamber during the compression phase ensures that the vacuum level of the rotary piston machine remains undisturbed. The introduced air reduces internal compression.

[0012] If the ventilation duct opening is completely closed, the supply of air from outside into the working chamber is prevented.

[0013] It is advantageous if, during operation, the first and / or second rotor passes the ventilation duct opening. Preferably, the first and / or second rotor passes the pressure connection opening and / or the suction connection opening.

[0014] It is advantageous if the ventilation duct is substantially circular in cross-section. The ventilation duct opening is preferably smaller, in particular significantly smaller, than the pressure connection opening and / or the suction connection opening. It preferably has an area between 10 mm2 and 200 mm2, preferably between 20 mm2 and 100 mm2. The area of the ventilation duct opening is advantageously between 1% and 10%, preferably between 2% and 10%, preferably between 2% and 5%, of the area of the suction connection opening. It is advantageous if it is between 7% and 20%, preferably between 10% and 16%, of the area of the pressure connection opening.

[0015] The housing advantageously has a housing base part and a first and second end part connected to the housing base part. The end parts are preferably connected to the housing base part opposite one another, in particular detachably.

[0016] The working chamber preferably has a cross-section formed by two intersecting circles forming an "8".

[0017] Gas can be introduced into the working chamber or the working sub-chambers via the suction port. It is advantageous if the suction port opens into the working chamber or at least one of the working sub-chambers via at least one suction port opening. The suction port opening is located in a suction area of the rotary piston machine.

[0018] Gas, particularly pressurized or vacuum-pressurized gas, can be discharged from the working chamber or from a working subchamber via the pressure connection. It is advantageous if the pressure connection is connected to the working chamber or at least one of the working subchambers, particularly the first working subchamber, via at least one pressure connection opening. The pressure connection opening is located in a pressure area of the rotary piston machine.

[0019] Each working subchamber is preferably spatially delimited on the outside by a working chamber wall of the housing, which extends in a circular arc at least in some areas on the inside. The associated rotor sweeps along the working chamber wall.

[0020] The rotors advantageously operate without contact and are preferably designed differently. They are adapted to one another. During operation, they preferably rotate in opposite directions to one another and then advantageously mesh with one another at least temporarily. Each rotor preferably has at least two rotor blades, which are preferably claw-like. Each rotor blade preferably has a claw and a claw recess. It is expedient if the first and / or second rotor, depending on the respective rotational position, controls or influences the suction connection and / or pressure connection, in particular at the front, with its rotor blades at least temporarily, in particular closing or opening them.

[0021] Further advantageous embodiments of the invention are specified in the subclaims.

[0022] The rotary piston machine according to subclaim 2 is particularly efficient. The operating pressure or the final pressure of the rotary piston machine is achieved in one stage or in one step, in particular from atmospheric pressure.

[0023] The first rotor according to dependent claim 3 is arranged or configured such that it, particularly at the front end, particularly with its rotor blades, controls or influences the effective cross-section of the ventilation duct opening. Depending on the respective rotational position of the first rotor, the ventilation duct opening is completely open, completely closed, or partially open / closed. Advantageously, the first rotor forms a control piston.

[0024] Preferably, in the shared working chamber phase of the rotors, the ventilation duct opening is completely closed, preventing any air supply from the outside. In the shared working chamber phase, a first working chamber, spatially delimited by the first rotor in the first working chamber, is in flow communication with a second working chamber, spatially delimited by the second rotor, in the second working chamber. The working chambers are adjacent to one another. They are preferably located on a common side of the rotary piston machine. It is expedient if the second rotor forms a delivery piston.

[0025] Optionally, the pressure port can be completely closed during the shared working chamber phase. This is preferably done by the first rotor and the second rotor. This allows for extremely effective compression of the gas in the working chamber. Release of gas from the working chamber is prevented during the shared working chamber phase.

[0026] A free dead space is preferably present between the rotors, at least temporarily, during the shared working chamber phase. It is expedient if the dead space is located in a central area of the working chamber.

[0027] Preferably, the pressure port is completely closed during the compression phase. This allows for particularly simple and efficient attainment of the operating pressure.

[0028] Further preferably, the ventilation channel opening is completely closed during an expulsion phase, in particular by the first rotor. This effectively prevents the rotor arrangement from expelling the gas via the ventilation channel.

[0029] Preferably, the pressure port is at least partially open during the expulsion phase. This allows the gas to be safely expelled from the working chamber via the pressure port.

[0030] The ventilation duct opening according to dependent claim 5 is arranged in a pressure region of the rotary piston engine. There, a pressure exists that is altered, such as increased or reduced, compared to the original, in particular atmospheric, pressure. The ventilation duct opening is thus arranged at a distance from a suction region of the rotary piston engine.

[0031] According to subclaim 6, the ventilation channel opening is arranged adjacent to, but spaced from, the pressure connection opening of the pressure connection. In particular, the ventilation channel opening is arranged upstream of the pressure connection opening in the direction of rotation of the first rotor.

[0032] According to subclaim 9, the end part is designed as a bearing shield, in particular a B-bearing shield. It is advantageous if this carries at least one bearing for supporting the rotor assembly. The end part is preferably removable.

[0033] A preferred embodiment of the invention is described below by way of example with reference to the accompanying drawings. In the drawings: Fig. 1 bis 6 Cross sections of a rotary piston machine according to the invention, illustrating successive positions of the rotor arrangement and their interaction with the suction port, pressure port and ventilation duct.

[0034] One in the Fig. 1 bis 6 The partially illustrated rotary piston machine comprises a housing 1 that spatially defines a working chamber 2. An actuatable rotor assembly 3 is arranged in the working chamber 2. The rotary piston machine also has a suction connection 4, which opens into the working chamber 2 via a suction connection opening 5. Furthermore, the rotary piston machine has a pressure connection 6 arranged at a distance from the suction connection 4, which is in flow connection with the working chamber 2 via a pressure connection opening 7. In addition, the rotary piston machine has a ventilation duct 8, which opens into the working chamber 2 via a ventilation duct opening 9.

[0035] The housing 1 is made up of several parts. It comprises a first bearing plate 10 and a housing base 11, as well as a second bearing plate (not shown). When the housing 1 is assembled, the bearing plates 10 are arranged on opposite sides of the housing base 11.

[0036] The bearing shields 10 and the housing base part 11 together delimit the working chamber 2. The bearing shields 10 spatially delimit the working chamber 2 in the longitudinal direction or axially, while the housing base part 11 or its working chamber wall spatially delimits the working chamber 2 laterally outwards or radially outwards.

[0037] The working chamber 2 has a first working sub-chamber 12 and a second working sub-chamber 13, which are essentially identical in design. The working sub-chambers 12, 13 are arranged side by side and are in direct flow communication with each other. They are open to each other in a connecting area.

[0038] A first rotor 14 of the rotor assembly 3 is arranged in the first working subchamber 12. The first rotor 14 is mounted in a rotationally fixed manner on a first rotor shaft 15, which is mounted in the housing 1 so as to be rotatable or rotatably driven about its first longitudinal central axis 16.

[0039] The Fig. 1 The contour of the first rotor 14 shown is point-symmetrical with respect to the first longitudinal center axis 16. It has two opposing first rotor blades 17 that protrude from a first rotor base body. Each first rotor blade 17 has a first claw 18 and a first claw recess 19 defined by the first claw 18. The first claw recesses 19 are open radially outward with respect to the first longitudinal center axis 16. They are spatially delimited by the first claws 18, counter to a first direction of rotation 20 of the first rotor 14 and also partially radially outward.

[0040] A second rotor 21 of the rotor assembly 3 is arranged in the second working subchamber 13. The second rotor 21 is mounted in a rotationally fixed manner on a second rotor shaft 22, which is arranged in the housing 1 so as to be rotatable or rotatably driven about its second longitudinal central axis 23. The rotor shafts 15, 22 run parallel to each other.

[0041] The second rotor 21 is point-symmetrical with respect to the second longitudinal central axis 23. It comprises two opposing second rotor blades 24 that protrude from a second rotor base body. Each second rotor blade 24 has a second claw 25 and a second claw recess 26 defined by the second claw 25. The second claw recesses 26 are open radially outward with respect to the second longitudinal central axis 23. They are spatially delimited by the second claws 25, counter to a second direction of rotation 27 of the second rotor 21 and also partially radially outward.

[0042] The first rotor 14 and the first rotor shaft 15 are, for example, connected to one another as a single piece. Alternatively, they are designed separately. The same applies to the second rotor 21 and the second rotor shaft 22.

[0043] Each rotor shaft 15, 22 is preferably supported on both sides in the housing 1. The first rotor shaft 14 is preferably connected to a drive. The rotor shafts 15, 22 are preferably connected to each other via a synchronization gear.

[0044] The first claws 18 are dimensioned or shaped such that, upon rotation in the first direction of rotation 20, they extend tightly along the inside of the housing base part 11. The second claws 25 are dimensioned or shaped such that, upon rotation in the second direction of rotation 27, they extend tightly along the inside of the housing base part 11.

[0045] The suction port 4 is located in the first bearing plate 10. Via the suction port opening 5, the suction port 4 opens eccentrically into the first working subchamber 12 and the second working subchamber 13. The suction port opening 5 is primarily located in the second working subchamber 13.

[0046] The pressure connection 6 is arranged in the first bearing plate 10. The pressure connection 6 opens eccentrically into the first working subchamber 12 via the pressure connection opening 7.

[0047] The ventilation duct 8 is arranged in the first bearing plate 10. The ventilation duct 8 opens eccentrically into the first working subchamber 12 via the ventilation duct opening 9. The ventilation duct opening 9 is arranged adjacent to the pressure connection opening 7. It is arranged between the suction connection opening 5 and the pressure connection opening 7 in the first direction of rotation 20. With respect to the first direction of rotation 20, the ventilation duct opening 9 is arranged upstream of the pressure connection opening 7 and downstream of the suction connection opening 5.

[0048] The ventilation duct opening 9 is substantially smaller than the pressure connection opening 7. It is substantially smaller than the suction connection opening 5, which is larger, in particular substantially larger, than the pressure connection opening 7. The area of the ventilation duct opening 9 is between 1% and 10%, more preferably between 2% and 5%, of the area of the suction connection opening 5. It is between 7% and 20%, more preferably between 10% and 16%, of the area of the pressure connection opening 7.

[0049] The operation of the rotary piston machine is described below. The first rotor shaft 15 is set in rotation about the first longitudinal center axis 16 in the first direction of rotation 20 by the drive. The second rotor shaft 22 is also set in rotation via the synchronization gear acting between the first rotor shaft 15 and the second rotor shaft 22. The rotor shafts 15, 22 and thus also the rotors 14, 21 are driven in opposite directions. The rotors 14, 21 interact and are temporarily in meshing engagement with each other.

[0050] Fig. 1 Illustrates the beginning of an intake cycle of the rotary piston engine. The intake port 5 is only partially closed by the first rotor 14 and the second rotor 21. Conversely, it is partially open. Gas can thus flow into the first working subchamber 12 and the second working subchamber 13 via the intake port 4.

[0051] The pressure connection opening 7 is completely closed by the first rotor 14.

[0052] The first rotor 14 and the second rotor 21 block a flow connection between the suction connection opening 5 and the ventilation channel opening 9. A first claw 18 of the first rotor 14 engages in a second claw recess 26 of the second rotor 21.

[0053] The rotors 14, 21, together with the housing 1, define an intake or inlet chamber 32 in the working chamber 2, which adjoins the intake connection opening 5 on both sides and extends into the first and second working subchambers 12 and 13, respectively. The intake or inlet chamber 32 expands during the intake cycle due to the rotation of the rotors 14, 21. It is closed.

[0054] The ventilation duct opening 9 is completely open. It is uncovered. A working space 33, which is essentially spatially limited by the housing 1 and the second rotor 21 and is located in the second working subchamber 13, is according to Fig. 1 shortly before isochoric transport.

[0055] In the working chamber 33 of the rotary piston machine, a static negative pressure with respect to the atmospheric pressure prevails due to the kinematics of the gas caused by the rotation of the second rotor 21.

[0056] A relaxation / ventilation chamber 34 of the rotary piston machine extends into Fig. 1 in the first working sub-chamber 12 and the second working sub-chamber 13. It is spatially separated from the intake or inlet chamber 32 and the working chamber 33. The expansion / ventilation chamber 34 is spatially delimited by the first rotor 14, the second rotor 21, and the housing 1.

[0057] The ventilation duct opening 9 is in Fig. 1 in flow communication with the expansion / ventilation chamber 34. Depending on the operating point reached, the expansion / ventilation chamber 34 is under either overpressure or underpressure relative to atmospheric pressure.

[0058] If there is an overpressure in the expansion / ventilation space 34 with respect to the atmospheric pressure, the expansion / ventilation space 34 or the gas enclosed therein is released into the atmosphere via the ventilation duct opening 9 or the ventilation duct 8.

[0059] If, however, an operating point is reached at which internal compression in the expansion / ventilation chamber 34 is insufficient to raise the static pressure to atmospheric pressure, a negative pressure relative to atmospheric pressure prevails in the expansion / ventilation chamber 34 even shortly before opening or reaching the pressure connection opening 7. In this case, the expansion / ventilation chamber 34 is then ventilated to atmospheric pressure via the ventilation duct opening 9 or the ventilation duct 8. At this operating point, the negative pressure in the expansion / ventilation chamber 34 is preferably less than 400 mbar(a) relative to atmospheric pressure.

[0060] How Fig. 2 shows, the intake cycle is followed by an isochoric transport cycle for the isochoric transport of the sucked-in gas enclosed in the intake chamber 32. The intake chamber 32 or the gas enclosed therein was divided by rotation of the rotors 14, 21 in the respective direction of rotation 20 or 27 through an angular range of 50° to 75° into / into two separate, mutually separated transport chambers 28, 29, which face away from each other and are delimited by the housing 1 and the respective rotor 14 or 21. Each first and second transport chamber 28 or 29 is arranged and closed off in the respective working sub-chamber 12, 13. The transport chambers 28, 29 or the gas enclosed therein are / is displaced isochorically. The rotors 14, 21 are disengaged. In particular, the claws 18 and 25, respectively, and the claw recesses 19, 26 of the rotors 14, 21 are disengaged. The second transport chamber 29 essentially corresponds to the working chamber 33.

[0061] The pressure port 7 is mostly open. The first rotor 14 opens the pressure port 7. The expansion / ventilation chamber 34 has shrunk in size.

[0062] The suction port 5 remains partially open. This allows gas to enter the working chamber 2 for a new cycle. The rotary piston machine with rotors 14, 21 allows two suction and discharge cycles per rotor revolution.

[0063] The ventilation channel opening 9 is completely closed by the first rotor 14.

[0064] How Fig. 3 shows, the isochoric transport cycle is followed by a common working chamber phase. The two transport chambers 28, 29 are merged into a closed common working chamber 30 by rotation of the rotors 14, 21 in the respective direction of rotation 20 and 27 by an angular range of 55° to 85°. The closed common working chamber 30 is separated from the partially open suction connection opening 5 by the rotors 14, 21. It is arranged at a distance from the suction connection opening 5. It extends over the first working sub-chamber 12 and the second working sub-chamber 13. A second claw 25 of the second rotor 21 engages in a first claw recess 19 of the first rotor 14.

[0065] The pressure connection opening 7 is almost completely closed by the first rotor 14. The second rotor 21 blocks a flow connection between the pressure connection opening 7 and the common working chamber 30.

[0066] The ventilation channel opening 9 is completely closed by the first rotor 14.

[0067] The common working space phase is followed by a dead space inclusion and dead space return phase by rotating the rotors 14, 21 in the respective direction of rotation 20 and 27 by an angular range of 5° to 35°, which Fig. 4 A dead space 31 is enclosed between the first rotor 14 and the second rotor 21 in a central region of the housing 1 in the working chamber 2 between adjacent claws 18 and 25, respectively, or between adjacent claw recesses 19, 26. The dead space 31 is sealed. It lies between the rotor shafts 15, 22. In the dead space containment and dead space return phases, the dead space 31 is enclosed and returned to the suction area.

[0068] The ventilation channel opening 9 is gradually opened by the first rotor 14. The first rotor 14 opens the ventilation channel opening 9.

[0069] The pressure connection opening 7 is completely closed by the first rotor 14.

[0070] The suction connection opening 5 is still partially open.

[0071] The dead space inclusion and dead space return phase is followed by a rotation of the rotors 14, 21 in the respective direction of rotation 20 and 27 by an angular range of 45° to 75°. Fig. 5 This phase is shown in the ventilation duct opening phase, in which the ventilation duct opening 9 is completely open and the working chamber 30 is filled with ambient air and charged to ambient pressure. The working chamber 30 decreases in volume. This advantageously allows compressed air or a vacuum to be generated. The first rotor 14 is rotated relative to the ventilation duct opening 9.

[0072] The first rotor 14 also gradually releases the pressure port 7. It opens it. Gas can then leave the working chamber 2 via the pressure channel 6.

[0073] The suction connection opening 5 is still partially open.

[0074] The rotors 14, 21 are disengaged.

[0075] The ventilation channel opening phase is followed by a rotation of the rotors 14, 21 in the respective direction of rotation 20 or 27 by an angular range of 5° to 30°. Fig. 6 shown further phase, in which the ventilation channel opening 9 is completely closed by the first rotor 14. The rotors 14, 21 are disengaged.

[0076] The pressure connection opening 7 is at least partially open.

[0077] The suction connection opening 5 is still partially open.

[0078] This is followed by the Fig. 1 Intake phase shown. In a rotary piston machine with a dual rotor claw design, two suction and discharge cycles are performed per rotor revolution.

[0079] The first rotor 14 forms a control rotor with respect to the ventilation duct opening 9.

Claims

1. A rotary piston engine, comprising a) a housing (1) spatially limiting a working chamber (2), b) an intake connection (4) for guiding gas into the working chamber (2), c) a pressure connection (6), connected to the working chamber (2), for guiding the gas out of the working chamber (2), d) a rotor assembly (4) having i) a first rotor (14) rotatably arranged in a first working sub-chamber (12) of the working chamber (2), and ii) a second rotor (21) rotatably arranged in a second working sub-chamber (13) of the working chamber (2) and cooperating with the first rotor (14), characterised by e) an expansion / ventilation space (34) which extends in the first working sub-chamber (12) and the second working sub-chamber (13), and f) a ventilation channel (8), formed in the housing (1) and connected to the working chamber (2) via a ventilation channel opening (9), both for the expansion and for the ventilation of the expansion / ventilation space (34).

2. The rotary piston engine according to Claim 1, characterised in that it is one-stage.

3. The rotary piston engine according to Claim 1 or 2, characterised in that the ventilation channel opening (9) is controllable, in particular releasable and / or closable, via the first rotor (14).

4. The rotary piston engine according to any one of the preceding claims, characterised in that the ventilation channel opening (9) is completely open prior to opening of the pressure connection (6).

5. The rotary piston engine according to any one of the preceding claims, characterised in that the ventilation channel opening (9) is arranged in a pressure region of the rotary piston engine.

6. The rotary piston engine according to any one of the preceding claims, characterised in that the ventilation channel opening (9) is arranged alongside a pressure connection opening (7), arranged in the working chamber (2), of the pressure connection (6).

7. The rotary piston engine according to any one of the preceding claims, characterised in that the ventilation channel opening (9) opens out into the working chamber (2) at a distance from the dead space (31) between the first rotor (14) and the second rotor (21).

8. The rotary piston engine according to any one of the preceding claims, characterised in that the ventilation channel opening (9) is completely closed, in particular by the first rotor (14), during closure of the dead space (31) between the first rotor (14) and the second rotor (21).

9. The rotary piston engine according to any one of the preceding claims, characterised in that the ventilation channel (8) is arranged in a first end part (10) of the housing (1), which is embodied as a bearing plate, in particular a B bearing plate.