Gerotor pump and motor-pump unit

Abstract

The application relates to a gerotor pump (1) for pumping a fluid from an inlet pump chamber (3) connected to an inlet (2) to an outlet pump chamber (5) of the gerotor pump (1) connected to an outlet (4), comprising a rotatable outer rotor (6); a rotatable inner rotor (7) which is arranged radially inside the outer rotor (6), wherein the inner rotor (7) and the outer rotor (6) have different axes of rotation (8, 9); a housing (10) with a housing space (11) in which the outer rotor (6) and the inner rotor (7) are accommodated;and a plurality of radially displaceable pressure elements (12, 32, 35) arranged on an outer circumference (13) of the outer rotor (6) and bearing against the housing (10) during operation, such that fluid-connected pressure chambers (14, 25, 33) are formed between the outer rotor (6) and the housing (10) and / or between the outer rotor (6) and the pressure elements (12, 32, 35) with the inlet pump chamber (3) and / or with the outlet pump chamber (5). The application also relates to a motor-pump unit (100) comprising the gerotor pump (1).

Description

[0001] The invention relates to a gerotor pump for conveying a fluid and a motor-pump unit comprising the gerotor pump.

[0002] Conventional gerotor pumps, also known as "gear pumps" or "Eaton pumps," feature a rotating outer rotor and a rotating inner rotor, with the inner rotor arranged radially inside the outer rotor. The inner rotor is typically driven by a motor. The inner rotor is designed as a gear and the outer rotor as a toothed ring, with the inner and outer rotors having different axes of rotation. This causes the outer rotor to rotate eccentrically on the outer teeth of the inner rotor. Due to the changing volumes between the tooth gaps of the inner and outer rotors, pressure zones, also called pump chambers, are formed, through which the fluid is pumped.

[0003] "Fundamentals of Designing Hydraulic Gear Machines" by Jaroslaw Stryczek (ISBN: 978-83-01-21226-1) and "Axial clearance compensation in the gerotor pump" by Jaroslaw Stryczek and Slawomir Bednarczyk from "the 19th International Conference on Hydraulics and Pneumatics, Prague, September 29 - October 1, 2008" describe conventional axial compensation in gerotor pumps using compensation plates.

[0004] Conventional gerotor pumps, however, have the disadvantage that manufacturing tolerances lead to a so-called tooth backlash between the teeth of the inner and outer rotors. This creates a gap, particularly between opposing teeth of the inner and outer rotors. This tooth backlash is already present when the pump is at rest, i.e., even when the pump is not running. When the pump is operating, the pressure increases and further widens the gap between the inner and outer rotors, causing internal leakage and reducing the pump's efficiency.

[0005] The object of the invention is to provide a gerotor pump which can reduce backlash between the inner and outer rotors during operation by radial compensation, thereby achieving high efficiency. It is also an object of the invention to provide a motor-pump unit which likewise exhibits high efficiency.

[0006] This problem is solved by the features of the dependent claims. The sub-claims describe advantageous embodiments of the invention.

[0007] This problem is solved in particular by a gerotor pump according to claim 1. The gerotor pump is designed and suitable for pumping a fluid from an inlet pump chamber connected to an inlet to an outlet pump chamber of the gerotor pump connected to an outlet. The gerotor pump has a rotatable outer rotor and a rotatable inner rotor. The inner rotor is arranged radially inside the outer rotor. The inner rotor and the outer rotor have different axes of rotation. Furthermore, the gerotor pump has a housing with a housing chamber in which the outer rotor and the inner rotor are received. The gerotor pump also has a plurality of radially displaceable pressure elements. The pressure elements are arranged on an outer circumference of the outer rotor.During operation of the gerotor pump, the pressure elements are in contact with the housing, so that pressure chambers are formed between the outer rotor and the housing and / or between the outer rotor and the pressure elements. The pressure chambers are fluid-connected to the inlet pump chamber and / or the outlet pump chamber.

[0008] During pump operation, pressure chambers form between the outer rotor and the casing and / or between the outer rotor and the pressure elements. These pressure chambers generate a force that presses the outer rotor radially against the inner rotor. This effect is also known as "radial compensation." This reduces the gap between the outer and inner rotors, especially at increasing pressures during pump operation, thus increasing efficiency.

[0009] The pressure chambers are advantageously defined as corresponding pressure zones of the fluid to be conveyed, which are separate from or in addition to the pressure zones between the outer and inner rotors through which the fluid is primarily conveyed. To distinguish them, the pressure zones formed between the outer and inner rotors for the main fluid conveyance are also called "primary pressure zones," and the pressure chambers defined above for radial compensation, which are generated by the pressure elements, are also called "secondary pressure zones."

[0010] In certain embodiments, the gerotor pump has at least two pressure elements. Particularly preferably, the gerotor pump has at least three to seven, and more preferably at least eight, pressure elements. Most preferably, the gerotor pump has exactly eight pressure elements or exactly six pressure elements.

[0011] In an advantageous embodiment, the housing has a plurality of openings along its inner circumference, in each of which a pressure element is at least partially arranged. The openings (hereinafter also referred to as "openings") are advantageously slots and / or bores. Advantageously, the pressure elements bear against the housing within the opening along one circumferential direction. The pressure elements bear against the outer circumference of the outer rotor or are positioned or biased against the outer circumference of the outer rotor.

[0012] The housing openings are advantageously connected to the inlet pump chamber and / or the outlet pump chamber. In other words, the fluid to be pumped reaches the openings. This has the advantage that, during operation of the gerotor pump, the pressure elements in the openings are actuated against the outer rotor by hydraulic pressure, thus forming the secondary pressure zones. Furthermore, placing the pressure elements in housing openings eliminates the need for modifications to the inner or outer rotor, thereby simplifying the manufacturing of the gerotor pump.

[0013] Advantageously, the gerotor pump has a plurality of spring elements, each arranged in one of the housing openings. The spring elements pre-tension the respective pressure element (in the same housing opening) against the outer rotor. In other words, the spring element presses the pressure element against the outer rotor.

[0014] The spring elements are advantageously coil springs or leaf springs, with different types of spring elements being arranged in different housing openings. Furthermore, several spring elements can be arranged in one housing opening. For example, two coil springs can be arranged in one housing opening. Alternatively, or in other housing openings, a (single) leaf spring can be arranged in the housing opening.

[0015] In an advantageous embodiment, the outer rotor has a plurality of openings along its outer circumference, in each of which a pressure element is at least partially arranged. The openings are advantageously slots and / or bores. The openings are fluidly connected to the inlet pump chamber and / or the outlet pump chamber. In other words, the fluid to be pumped reaches the openings. This has the advantage that the pressure elements located between the outer rotor and the housing can be at least partially accommodated by the outer rotor. This advantageously reduces the size of the gerotor pump.

[0016] The pressure elements are radially displaceable and advantageously arranged at least partially within the aforementioned openings / housing openings. In a case where the pressure elements are arranged in openings of the outer rotor, they can, for example, be completely within their respective openings when the pump is at rest and, during operation, be displaced radially outwards by a centrifugal force so that they are only partially within their respective openings. During operation, the pressure elements can all protrude from their respective openings by the same or similar amount, or they can protrude from their respective openings by different amounts.

[0017] In a case where the pressure elements are arranged in housing openings, the pressure elements can, for example, be completely enclosed within the respective opening when the pump is at rest. During operation of the pump, hydraulic pressure from the inlet pump chamber and / or the outlet pump chamber, which are fluidically connected to the opening, can actuate the respective pressure element against the outer rotor.

[0018] In another example, the pressure elements can also be positioned or pre-tensioned against the outer rotor by means of the spring elements when the pump is at rest.

[0019] In an advantageous embodiment, the housing has a housing cover and a housing base, between which (along the axial direction) the inner and outer rotors are arranged. Along the axial direction, gaps are provided between the housing cover and the inner and outer rotors, and between the housing base and the inner and outer rotors, which form parts of the inlet pumping chamber and the outlet pumping chamber, such that the fluid to be pumped axially surrounds the inner and outer rotors.

[0020] In preferred embodiments, the housing cover and / or the housing base advantageously have grooves which, together with the spaces between the inner and outer rotors, form the inlet pump chamber and the outlet pump chamber. The grooves advantageously extend at least partially along a circumferential direction of the outer rotor. In a top view, defined as a view of a cross-section of the outer and inner rotors perpendicular to the axes of rotation, the grooves are arranged on two sides in the circumferential direction of the inlet and / or the outlet and extend along the circumferential direction away from the inlet and / or the outlet.The grooves advantageously increase the volume of the inlet pump chamber and / or outlet pump chamber between the housing cover / base and the outer rotor and / or inner rotor, thereby reducing viscous friction with the fluid and thus reducing areas with necessary low clearance / tolerances, thereby increasing the efficiency of the pump.

[0021] In a preferred embodiment, the pressure elements are rotary slides. These pressure elements, designed as rotary slides, are preferably substantially rectangular and plate-shaped. Advantageously, the rotary slides have rounded corners.

[0022] It is further advantageous if at least one housing-side side surface of the rotary valves arranged in openings of the outer rotor, in particular the housing-side side surface that comes into contact with the housing, is rounded. This reduces friction between the rotary valve and the housing.

[0023] Advantageously, the height of the rotary valves along an axial direction of the outer rotor is less than the height of the outer rotor or less than the height of the housing in the axial direction. In other words, the axial depth of the opening, slot, or bore in the outer rotor or housing is advantageously greater than the height of the respective rotary valve. This has the advantage that the fluid to be pumped can flow from the inlet pump chamber along the rotary valve into the housing space between the outer rotor and the housing, or into the housing opening, with particularly low viscous friction. By adjusting the height of the rotary valves, the amount of fluid flowing along the rotary valve, as described above, can be controlled, thus controlling the pressure between the pressure chambers created by the rotary valves. In special embodiments, the rotary valves have different heights, or they all have the same height.

[0024] In some special embodiments, the height of the rotary valves is 90%, preferably 95%, and even more preferably 98%, of the height of the outer rotor or the housing. Preferably, the difference in height between the outer rotor or the housing and the rotary valves is greater than (merely) due to manufacturing tolerances. This allows for a particularly effective rotary valve operation and a reduction in friction. Alternatively, the height of the rotary valves can be approximately 50% of the height of the outer rotor or the housing.

[0025] The aforementioned height is to be understood in particular as the (axial) length of the aforementioned housing-side side surface or the aforementioned outer rotor-side side surface.

[0026] In an advantageous embodiment, the rotary valves divide the housing space at least section by section along a circumferential direction of the outer rotor. During operation, pressure chambers are formed at least between the rotary valves along the circumferential direction. These pressure chambers are preferably formed in addition to the primary pressure zones described above (between the inner and outer rotors). These pressure chambers are advantageously formed along the circumferential direction between the rotary valves and radially between the outer rotor and the housing. During pump operation, the fluid pressures in the pressure chambers are advantageously not axially symmetrical with respect to the axial direction or with respect to the axes of rotation of the outer and / or inner rotor. In other words, the pressure that arises within the pressure chambers differs between at least some of the pressure chambers.This advantageously creates a force that positions the outer rotor against the inner rotor, thus reducing the gap between them and increasing efficiency.

[0027] In an advantageous embodiment, the pressure elements are each piston. Advantageously, the respective opening is designed as a bore in which the respective piston is arranged to be radially displaceable. The opening is fluidly connected to the inlet pump chamber and / or the outlet pump chamber.

[0028] In a case where the pistons are located in the outer rotor, the piston is moved radially inwards during pump operation, exerting pressure on the fluid in the opening. This pressure, in turn, exerts a force on the outer rotor, which tilts it against the inner rotor and reduces the gap, thus increasing efficiency. In a case where the pistons are located in the casing, the piston is moved radially inwards during pump operation by the pressure in the inlet or outlet pump chamber, causing the piston to tilt the outer rotor against the inner rotor and reducing the gap, thus increasing efficiency.

[0029] Advantageously, each piston seals a radially housing-side end of the opening in the outer rotor or a radially outer-rotor-side end of the opening in the housing. In other words, each opening in the outer rotor in which such a piston is arranged has a radially inner end (inner-rotor-side) and a radially outer end (housing-side), with the piston slidably projecting at least partially from the housing-side end. A radial inner surface of the opening in the outer rotor, which is an inner surface of the opening at its radial inner end and which is fluidly connected to the inlet pump chamber and / or the outlet pump chamber, forms a piston pressure chamber with the piston. In a case where the piston is arranged in an opening of the housing, the radially inner end of the opening is on the outer-rotor side and the radially outer end of the opening is located radially further outwards in the housing.The piston pressure chamber is formed between the radially outer end of the housing opening and the piston, which is arranged between the housing and the outer rotor.

[0030] In other words, the piston and the opening together form a piston-cylinder arrangement. The piston pressure chamber advantageously exerts the actuating force described above on the outer rotor, thus increasing the pump's efficiency.

[0031] The radially inner end of the opening in the outer rotor or the radially outer end of the housing opening is preferably connected to the space between the outer rotor and the housing cover or, depending on the axial orientation of the opening, to the space between the outer rotor and the housing base, so that the fluid in this space can flow into the opening.

[0032] Advantageously, the design of the pressure elements as rotary valves and pistons can be combined. For example, at least one pressure element is designed as a rotary valve and at least one as a piston. Furthermore, a pressure element can be functionally designed simultaneously as a rotary valve and as a piston, for example, by designing the rotary valve as a piston with an axial height of at least 50% or 90%, or one of the other values ​​mentioned above for rotary valves, such as the height of the outer rotor. Advantageously, such pistons separate the housing space at least section by section along the circumferential direction of the outer rotor and, in addition to the piston pressure chambers, form further pressure chambers between the outer rotor and the housing along the circumferential direction.

[0033] In an alternative embodiment, the outer rotor and the housing have different axes of center perpendicular to the radial direction. Specifically, the axis of center of the housing and the axis of rotation of the outer rotor do not coincide. In other words, the outer rotor is not located centrally within the housing. This has the advantage that the secondary pressure chambers are asymmetrical, and a force resulting from these chambers causes the outer rotor to turn against the inner rotor, thus increasing efficiency. Due to the differing axes of center, the angular or circumferential position of the maximum generated pressure in the secondary pressure chambers changes accordingly during pump operation, so that a resulting pressure force from all secondary pressure chambers counteracts the resulting pressure force from the primary pressure chambers that turns the outer rotor.If the pressure force from the primary pressure chambers is more than compensated (more than completely counteracted), the gap between the outer rotor and inner rotor is reduced, which can further increase efficiency.

[0034] Preferably, the outer rotor has at least one, and in particular a plurality, of outer rotor grooves distributed along the circumferential direction. The outer rotor grooves are formed, in particular, along the circumferential direction between the aforementioned openings. The outer rotor grooves advantageously reduce viscous friction with the fluid between the outer rotor and the housing cover and / or housing base. The outer rotor grooves can be formed on one or both axial sides of the outer rotor (housing base side and / or housing cover side). The outer rotor grooves are formed, in particular, as axially deep, elongated recesses in the outer rotor. Preferably, the inner rotor can also have such corresponding grooves (inner rotor grooves).

[0035] Preferably, the housing has at least one, and in particular a plurality, of housing grooves distributed along the circumferential direction. The housing grooves are formed, in particular, along the circumferential direction between the aforementioned housing openings. The housing grooves advantageously reduce viscous friction with the fluid between the housing and the housing cover and / or housing base. The housing grooves can be formed on one or both axial sides of the housing (housing base side and / or housing cover side). The housing grooves are formed, in particular, as recesses in the housing that are elongated along the circumferential direction and axially deep. Preferably, the inner rotor and / or the outer rotor can have such grooves.

[0036] In some designs, the gerotor pump also features at least one compensation plate, which is arranged axially between the housing cover and / or base and the inner and / or outer rotor, enabling axial compensation of the gerotor pump. This advantageously gives the gerotor pump both radial and axial compensation, resulting in a particularly high efficiency.

[0037] The invention also relates to a motor-pump unit. The motor-pump unit comprises a gerotor pump according to one of the aforementioned preferred embodiments. Furthermore, the motor-pump unit comprises a motor which is connected to the inner rotor and is configured to rotate the inner rotor to operate the gerotor pump. The motor is, in particular, mechanically connected to the inner rotor by means of a shaft. The motor-pump unit exhibits increased efficiency.

[0038] The gerotor pump and the motor-pump unit also offer the following advantages. By compensating for tolerances (radial compensation or radial compensation with axial compensation), the components can be manufactured at significantly reduced costs, as manufacturing tolerances can be considerably expanded. Due to the higher efficiency, they can be used in higher pressure ranges. Furthermore, radial compensation increases performance stability across various pressures. Moreover, no additional control system is required for the radial compensation described above, as it operates autonomously through a hydraulic principle.

[0039] The preferred configurations and effects described above are independent of the direction of rotation of the outer rotor or the inner rotor.

[0040] Further details, advantages and features of the present invention will become apparent from the following description of exemplary embodiments with reference to the drawing. It shows: Fig. 1 a schematic cross-sectional view of a gerotor pump according to a first embodiment of the present invention; Fig. 2 a schematic top view of the gerotor pump according to the first embodiment of the present invention; Fig. 3 a perspective detail view of an outer rotor of the gerotor pump according to the first embodiment of the present invention; Fig. 4 a perspective detail view of the outer rotor and a rotary valve of the gerotor pump according to the first embodiment of the present invention; Fig. 5 a schematic cross-sectional view of a gerotor pump according to a second embodiment of the present invention; Fig. 6 a schematic cross-sectional view of a gerotor pump according to a third embodiment of the present invention; Fig. 7 a further schematic sectional view of the gerotor pump according to the third embodiment of the present invention; and Fig. 8 a schematic block diagram of a motor-pump unit according to an embodiment of the present invention.

[0041] Fig. 1 Figure 1 shows a schematic cross-sectional view of a gerotor pump 1 according to a first embodiment of the present invention.

[0042] The gerotor pump 1 (hereinafter referred to as "pump 1") for pumping a fluid has a rotatable inner rotor 7 and a rotatable outer rotor 6. The inner rotor 7 is designed as a gear. The outer rotor 6 is designed as a toothed ring.

[0043] The inner rotor 7 and the outer rotor 6 are housed in a housing space 11 of a housing 10. The inner rotor 7 is arranged along a radial direction 15 within the outer rotor 6.

[0044] The inner rotor 7 is rotatable about an inner rotor axis 8, while the outer rotor 6 is rotatable about an outer rotor axis 9. As shown from Fig. 1 The axes of rotation 8 and 9 are clearly distinct from one another, i.e., arranged parallel to each other. During operation of pump 1, a rotation of the inner rotor 7 causes a rotation of the outer rotor 6. The operation of pump 1 is described below with reference to Fig. 2 explained.

[0045] As from Fig. 1 It is further evident that, in the present embodiment, the outer rotor 6 is not arranged centrally in the housing chamber 11, at least when the pump 1 is at rest. In other words, the center axes of the housing chamber 11 and the outer rotor 6 are different. In this case, the inner rotor 7 is arranged centrally in the housing chamber 11, such that a center axis of the housing chamber 11 coincides with the inner rotor's axis of rotation 8. The center axis of the outer rotor 6 coincides with the outer rotor's axis of rotation 9.

[0046] The outer rotor 6 has at least two, here eight, openings 16 on its outer circumference 13. The openings 16 are, as below with reference to Fig. 3 & 4As explained, the openings 16 are slots. In this case, the openings 16 are preferably evenly distributed around the outer circumference 13 of the outer rotor 6, i.e., arranged symmetrically. In an alternative embodiment, the openings 16 can be arranged asymmetrically along the outer circumference 13, such that different distances are formed between at least two pairs of openings 16 along the outer circumference 13.

[0047] A rotary valve 12 is arranged in each opening as a pressure element. The rotary valves 12 are radially displaceable within the respective openings 16. When the outer rotor 6 rotates, a centrifugal force resulting from the rotation causes the rotary valves 12 to protrude from the respective openings 16 and bear against the housing 10.

[0048] As explained below (see Fig. 2 During operation of pump 1, the fluid to be pumped is also partially located in the housing space 11 between the outer rotor 6 and the inner rotor 7. When the outer rotor 6 rotates, the rotary valves 12 form pressure chambers 14. The pressure chambers 14 are formed in the radial direction 15 between the outer rotor 7 and the housing 10 and along a circumferential direction 18 between the rotary valves 12.

[0049] Eccentric rotation of the outer rotor 6 within the housing space 11 creates pressure chambers 14 with different fluid pressures. These varying fluid pressures at different circumferential points around the outer rotor 6 generate a resultant force that acts against the inner rotor 7. In this case, the resultant force advantageously causes the outer rotor 6 to be pressed against the inner rotor 7 along a specified -y direction. This advantageously reduces the gap between opposing tips 19 of the outer rotor 6 and the inner rotor 7. At the locations of the opposing tips 19, a reduction in the gap between the outer rotor 6 and the inner rotor 7 has the greatest beneficial effect in reducing internal leakage and increasing the efficiency of the pump 1. This will be further illustrated by Fig. 2 explained.

[0050] Furthermore, the fluid is located partially within the respective opening 16 radially further inward than the respective rotary valve 12. The fluid is situated in an opening space 24 between a radial inner surface 17 of the opening 16 and the rotary valve 12, thus forming opening space pressure chambers 25. The opening space pressure chambers 25 provide spring action for the rotary valves 12 and, as explained below with reference to embodiment two, for an (additional) actuating force on the outer rotor 6. Alternatively or additionally, a spring element can be arranged in the respective opening space 24, which springs the rotary valve 12 or radially preloads / actuates it.

[0051] Fig. 2 Figure 1 shows a schematic top view of the gerotor pump 1 according to the first embodiment of the present invention. The figure shows the Fig. 2 in particular a housing cover 20, which covers the outer rotor 6, the inner rotor 7 and the housing chamber 11. The components covered by the housing cover 20 are indicated by dashed lines. For better clarity, the rotary valves 12 are shown in the Fig. 2 not shown.

[0052] More precisely, the pump 1 has a housing cover 20 and a housing base 21, the housing base 21 not being (directly) visible in the present view. The inner rotor 7 and the outer rotor 6 are arranged between the housing cover 20 and the housing base 21 along an axial direction 30 of the outer rotor 6, which coincides with the outer rotor's axis of rotation 9 (in this case, in the z-direction). A gap (axial gap) is formed between at least the housing cover 20 (and / or at least the housing base 21) and the outer rotor 6 and the inner rotor 7 along the axial direction 30, so that fluid surrounds the outer rotor 6 and the inner rotor 7.

[0053] The base of the housing 21 has openings for an inlet 2 and an outlet 4. The fluid is pumped by the pump 1 from the inlet 2 to the outlet 4. As further details are shown Fig. 2 The housing cover 20 has grooves 22, which extend along the circumferential direction 18 and are each connected to the inlet 2 or the outlet 4. The grooves 22, together with the spaces 23 between the teeth of the inner rotor 7 and the outer rotor 6 (hereinafter "volumes 23"), define an inlet pump chamber 3 and an outlet pump chamber 5 of the pump 1. The inlet pump chamber 3 and the outlet pump chamber 5 of the pump 1 also include the aforementioned fluid or fluid volume in the axial direction 30 between the housing cover 20 and / or housing base 21 and the outer rotor 6 and the inner rotor 7.

[0054] During operation of pump 1, fluid is conveyed from inlet 2 to outlet 4 along the circumferential direction 18. As shown at the Fig. 2 The volumes 23 of the spaces between the inlets 22 and the circumferential direction 18 (clockwise in this case) initially increase, drawing fluid in through the inlet 2. Subsequently, at the end of the groove 22 in the circumferential direction 18, the volumes 23 remain almost constant before decreasing. This reduction in volume towards the outlet 4 pressurizes the fluid, forcing it out of the outlet 4. The resulting pressure zones, through which the fluid is primarily conveyed between the inlet 2 and outlet 4, are called "primary pressure zones," while the pressure zones formed by the rotary valves 12 described above are called "secondary pressure zones."

[0055] At the points of the opposing tips 19, the separation of the volumes 23, and thus the efficiency of the pump 1, is particularly sensitive to manufacturing tolerances and to the angle of the outer rotor 6 at high fluid pressures due to the small contact areas of the teeth. The angle of the outer rotor 6 relative to the inner rotor 7, caused by the [missing information] with respect to Fig. 1 The rotary valve 12, which reduces the gap between the opposing tips 19, increases the efficiency of the pump 1.

[0056] Fig. 3 Figure 1 shows a perspective detail view of the outer rotor 6 of the gerotor pump 1 according to the first embodiment of the present invention. As shown in Figure 2, the following is a description of the illustration: Fig. 3 The outer rotor 6 is essentially a toothed ring with slots as openings 16 for receiving the rotary valves 12.

[0057] Furthermore, the outer rotor 6 has a plurality of outer rotor grooves 26, which are formed along the circumferential direction 18 between the openings 16. The outer rotor grooves 26 reduce viscous friction with the fluid between the outer rotor 6 and the housing cover 20 and / or the housing base 21.

[0058] Fig. 4 Figure 1 shows a perspective detail view of the outer rotor 6 and a rotary valve 12 of the gerotor pump 1 according to the first embodiment of the present invention. Fig. 4 The case base 21 is also shown.

[0059] As from the Fig. 4 The rotary valve 12 is clearly resting on the housing base 21. The height 27 of the rotary valve 12 is less than the height 28 of the outer rotor 6 with respect to the axial direction 30. In certain embodiments, the height 27 of the rotary valve 12 is between 90% and 98% of the height 28 of the outer rotor 6.

[0060] Due to the reduced height 27 of the rotary valve 12, fluid, represented by a fluid flow 29, can flow particularly easily from the inlet pump chamber 3 on the rotary valve 12 into the housing space 11 between the outer rotor 6 and the housing 10. In particular, the aforementioned fluid can flow particularly easily, i.e., with low viscous friction, between the housing cover 20 and the outer rotor 6 and inner rotor 7 (in the axial gap) into the housing space 11.

[0061] In this case, the rotary valve 12 also has a rounded housing-side side surface 31, which reduces friction between the rotary valve 12 and the housing 10.

[0062] Fig. 5 Figure 1 shows a schematic cross-sectional view of a gerotor pump 1 according to a second embodiment of the present invention.

[0063] In the present embodiment, the pressure elements are designed as pistons 32. The gerotor pump 1 has at least two, and in this case six, pistons 32. The openings 16 are designed as radial bores in the outer circumference 13 of the outer rotor 6. The pistons 32 are radially displaceable and seal a radially housing-side end 34 of the respective opening 16. Furthermore, the openings 16 are fluidly connected to the inlet pump chamber 3 and / or to the outlet pump chamber 5. For this purpose, the openings 16 have, as shown in Fig. 5 shown, another axial bore (depth direction in Fig. 5 ), which is connected to the radial bore. This essentially results in an L-shaped bore in the outer rotor 6, with the respective piston 32 arranged in the radial bore. This allows the fluid located between the housing cover 20 and the outer rotor 6 (in the axial gap) to flow through the axial part of the bores into the openings 6. In other words, the axial bore is fluidly connected to the axial gap.

[0064] This creates piston pressure chambers 33 between the radial inner surface 17 of the opening 16 and the respective pistons 32. When the outer rotor 6 rotates, the pistons 32 are pressed radially into the openings 16, pressurizing the fluid through the piston 32. This resulting pressure exerts a force on the radial inner surface 17 of the opening 16 and thus on the outer rotor 6, causing it to be turned against the inner rotor 7. The piston pressure chambers 33 are secondary pressure zones, similar to the pressure chambers 14 generated by the rotary valves 12.

[0065] How a comparison of Fig. 5 with the Fig. 1 As shown, the pistons 32 can also create the pressure chambers 14 between the outer rotor 6 and the housing 10 in the housing space 11. For this purpose, the pistons 32 can have a corresponding height 27 of the rotary valves 12.

[0066] In the preceding descriptions, the outer rotor 6 is not centrally located in the housing chamber 11, at least when the pump 1 is at rest. Alternatively, the outer rotor 6 can be centrally located in the housing chamber 11 when the pump 1 is at rest. In this case, a pressure difference between the inlet 2 and the outlet 4 (primary pressure zones) causes the outer rotor 6 to tilt during operation of the pump 1. This tilt, particularly at high pressures, also results in the outer rotor 6 being positioned off-center in the housing chamber 11, so that even in this case, secondary pressure zones are formed during operation of the pump 1. However, these secondary pressure zones counteract the tilt caused by the primary pressure zones, at least partially, so that the gap between the outer rotor 6 and the inner rotor 7 is reduced, at least during operation of the pump 1, and its efficiency is increased.

[0067] The Figuren 6 and 7Each shows a schematic sectional view of a gerotor pump 1 according to a third embodiment of the present invention.

[0068] In the present embodiment, as in particular in Fig. 6 As can be seen, the housing 10 has a plurality, here four, of openings 37, also called housing openings 37, along its inner circumference 36. In each of these housing openings 37, a radially displaceable pressure element in the form of a rotary valve 35 is arranged. Each rotary valve 35 rests, particularly during operation of the gerotor pump 10, along the circumferential direction 18 against at least one inner surface 41 of the housing 10 or of the housing opening 37.

[0069] Each rotary valve 35 projects from a radial inner surface 39 of the housing opening 37 and is arranged on the outer rotor 6. As can be seen in particular from Fig. 7 Each rotary valve 35 can be seen being positioned or pre-tensioned against the outer rotor 6 by a spring element 38, here a leaf spring.

[0070] How also the Fig. 7 As can be seen, the height 27 of the rotary valves 35 with respect to the axial direction 30 is less than the height 42 of the housing 10. In particular, the height 27 of the rotary valves 35 is less than the height 28 of the outer rotor 6. As a result, fluid from the housing space 11 between the housing cover 20 and the housing 10 can flow particularly easily, i.e., with low viscous friction, into the housing opening 37, as in the first embodiment.

[0071] Preferably, the housing cover 20 or the housing base 21 can have grooves that guide the fluid into the housing opening 37. In this case, for example, the spring element 38 can be functionally replaced, at least partially, by fluid in the housing opening 37, which directs the rotary valve 35 against the outer rotor 6.

[0072] Alternatively or in addition to the grooves in the housing cover 20 or in the housing base 21, the housing 10 can have one or more housing grooves 43, which are located in Fig. 6 The housing groove 43 is shown with a dashed line. This housing groove 43 is an axial recess in the housing 10 and connects two openings 37 to each other, so that they are fluid-connected. Furthermore, the housing groove 43 connects the two openings 37 to the housing chamber 11, so that the openings 37 are fluid-connected to it. This allows hydraulic pressure exerted by the fluid from the inlet pump chamber 3 and / or the outlet pump chamber 5 to actuate the rotary valves 35 against the outer rotor 6.

[0073] Furthermore, several housing grooves 43 can be arranged in the housing 10. In the present example of four openings 37, two housing grooves 43 can be formed, each connecting two of the four openings 37 to each other. This allows, for example, two of the openings 37 to be fluidly connected to the inlet pump chamber 3 and the other two of the openings 37 to the outlet pump chamber 5, without them being fluidly short-circuited (in pairs).

[0074] The rotary valves 35 of the present embodiment offer the same advantages as the rotary valves 12 of the first embodiment. In other words, the rotary valves 35 create pressure chambers 14 in the housing space 11 radially between the outer rotor 6 and the housing 10, thereby causing the outer rotor 6 to be turned.

[0075] The gerotor pump 1 according to the present embodiment can be combined with the gerotor pump 1 according to the first and / or the second embodiment. In particular, the rotary valves 35 of the present embodiment, apart from being arranged in the housing 10, and their associated openings 37 can have similar or identical configurations to the pressure elements 12, 32 and openings 16 of the first two embodiments. For example, the present rotary valves 35 can also be configured as pistons that actuate the outer rotor 6 against the inner rotor 7. This combination is particularly advantageously combinable with the aforementioned configuration in which the housing 10 has one or more housing grooves 43, in addition to or as an alternative to the possible grooves in the housing cover 20 or in the housing base 21.

[0076] The invention also relates to a motor-pump unit 100. This is in Fig. 8 Figure 1 shows a schematic block diagram of the motor-pump unit 100 according to an embodiment of the present invention.

[0077] The motor-pump unit 100 comprises a motor 101 and a gerotor pump 1 according to the preceding embodiments. The motor 101 is configured to rotate the inner rotor 7 to operate the gerotor pump 1. The motor 101 is connected by means of a shaft 102 (see also Fig. 2 ) mechanically connected to the inner rotor 7.

[0078] The motor-pump unit 100 has a particularly good efficiency and is less affected by tolerances.

[0079] In addition to the above written description of the invention, explicit reference is hereby made to the graphic representation of the invention in the figures for its supplementary disclosure. Bezugszeichenliste

[0080] 1 Gerotor pump 2 Inlet 3 Inlet pump chamber 4 Outlet 5 Outlet pump chamber 6 Outer rotor 7 Inner rotor 8 Inner rotor axis of rotation 9 Outer rotor axis of rotation 10 Housing 11 Housing space 12 Rotary valve 13 Outer circumference of the outer rotor 14 Pressure chamber 15 Radial direction 16 Opening 17 Radial inner surface 18 Circumferential direction 19 Opposing tips 20 Housing cover 21 Housing bottom 22 Groove 23 Intermediate space / volumes 24 Opening space 25 Opening space pressure chamber 26 Outer rotor groove 27 Height of the rotary valve 28 Height of the outer rotor 29 Fluid flow 30 Axial direction 31 Side surface 32 Piston 33 Piston pressure chamber 34 Radial housing-side end of the opening 35 Rotary valve 36 Inner circumference of the housing 37 Housing opening 38 Spring element 39 Radial inside of housing opening 40 Radial outside of housing opening 41 Inner surface of housing 42 Height of housing 43 Housing groove 100 Motor-pump unit 101 Motor 102 Shaft

Claims

1. Gerotor pump (1) for conveying a fluid from an inlet pump chamber (3) connected to an inlet (2) to an outlet pump chamber (5) of the gerotor pump (1) connected to an outlet (4), comprising: a rotatable outer rotor (6); a rotatable inner rotor (7) arranged radially inside the outer rotor (6), wherein the inner rotor (7) and the outer rotor (6) have different axes of rotation (8, 9); a housing (10) with a housing space (11) in which the outer rotor (6) and the inner rotor (7) are accommodated; and a plurality of radially displaceable pressure elements (12, 32, 35) which are arranged on an outer circumference (13) of the outer rotor (6) and bear against the housing (10) during operation, so that pressure chambers (14, 25, 33) which are fluidically connected to the inlet pump chamber (3) and / or to the outlet pump chamber (5) are formed between the outer rotor (6) and the housing (10) and / or between the outer rotor (6) and the pressure elements (12, 32, 35).

2. Gerotor pump (1) according to claim 1, wherein the housing (10) has along its inner circumference (36) a plurality of housing openings (37), in particular slots and / or bores, in each of which a pressure element (35) is at least partially arranged.

3. Gerotor pump (1) according to claim 2, further comprising a plurality of spring elements (38), each of which is arranged in a housing opening (37) and is configured to prestress the respective pressure element (35) toward the outer rotor (6).

4. Gerotor pump (1) according to claim 1, wherein the outer rotor (6) has a plurality of openings (16) along its outer circumference (13), in particular slots and / or bores, in each of which a pressure element (12, 32) is at least partially arranged, wherein the openings (16) are each fluidically connected to the inlet pumping chamber (3) and / or to the outlet pumping chamber (5).

5. Gerotor pump (1) according to one of the preceding claims, wherein the housing (10) has a housing cover (20) and a housing base (21), between which the inner rotor (7) and the outer rotor (6) are arranged and wherein the housing cover (20) and / or the housing base (21) have grooves (22) which, together with spaces (23) between the inner rotor (7) and the outer rotor (6), form the inlet and outlet pumping chambers (3, 5).

6. Gerotor pump (1) according to one of the preceding claims, wherein the pressure elements (12, 32, 35) are each rotary vanes (12, 35).

7. Gerotor pump (1) according to claim 6, wherein a height (27) of the rotary vanes (12, 35) along an axial direction (30) of the outer rotor (6) is less than a height (28) of the outer rotor (6) or than a height (42) of the housing (10) in the axial direction (30).

8. Gerotor pump (1) according to claim 6 or 7, wherein the rotary vanes (12, 35) at least partially separate the housing space (11) along a circumferential direction (18) of the outer rotor (6) and, during operation, pressure chambers (14) are formed at least between the rotary vanes (12, 35) along the circumferential direction (18).

9. Gerotor pump (1) according to one of claims 2 to 5, wherein the pressure elements (12, 32, 35) are each pistons (32).

10. Gerotor pump (1) according to one of claims 4 or 5, wherein the respective piston (32) seals a radial housing-side end (34) of the opening (16) and, during operation, forms a piston pressure chamber (33) with a radial inner side (17) of the opening (16), which is fluidically connected to the inlet pumping chamber (3) and / or to the outlet pumping chamber (5).

11. Gerotor pump (1) according to one of the preceding claims, wherein the outer rotor (6) and the housing space (11) have different center axes perpendicular to the radial direction (15).

12. A motor-pump unit (100) comprising: a gerotor pump (1) according to any one of the preceding claims; and a motor (101) connected to the inner rotor (7) and configured to rotate the inner rotor (7) to operate the gerotor pump (1).

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