Gerotor Pump And Motor/Pump Unit

Abstract

The invention relates to a gerotor pump for conveying a fluid from an inlet pump chamber which is connected to an inlet to an outlet pump chamber which is connected to an outlet of the gerotor pump, having a rotatable outer rotor; a rotatable inner rotor which is arranged radially inside the outer rotor, wherein the inner rotor and the outer rotor have rotation axes which are different from each other; a housing having a housing space, in which the outer rotor and the inner rotor are received; and; and a plurality of radially displaceable pressure elements which are arranged on an outer circumference of the outer rotor and which during operation bear on the housing so that between the outer rotor and housing and/or between the outer rotor and the pressure elements pressure chambers which are connected in fluid terms to the inlet pump chamber and/or to the outlet pump chamber are formed. The invention further relates to a motor/pump unit having the gerotor pump.

Claims

1. A gerotor pump for conveying a fluid from an inlet pump chamber which is connected to an inlet to an outlet pump chamber which is connected to an outlet of the gerotor pump having: a rotatable outer rotor; a rotatable inner rotor which is arranged radially inside the outer rotor, wherein the inner rotor and the outer rotor have rotation axes which are different from each other; a housing having a housing space, in which the outer rotor and the inner rotor are received; and a plurality of radially displaceable pressure elements which are arranged on an outer circumference of the outer rotor and which during operation bear on the housing so that between the outer rotor and housing and/or between the outer rotor and the pressure elements pressure chambers which are connected in fluid terms to the inlet pump chamber and/or to the outlet chamber pump are formed.

2. The gerotor pump as claimed in claim 1, wherein the housing has along an inner circumference thereof a plurality of housing openings, in particular slots and/or holes, in which a pressure element is at least partially arranged in each case.

3. The gerotor pump as claimed in claim 2, further having a plurality of resilient elements which are in each case arranged in a housing opening and which are configured to pretension the respective pressure element with respect to the outer rotor.

4. The gerotor pump as claimed in claim 1, wherein the outer rotor along the outer circumference thereof has a plurality of openings, in particular slots and/or holes, in which a pressure element is at least partially arranged in each case, wherein the openings are in each case connected in fluid terms to the inlet pump chamber and/or to the outlet pump chamber.

5. The gerotor pump as claimed in claim 1, wherein the housing has a housing cover and a housing base between which the inner rotor and the outer rotor are arranged and wherein the housing cover and/or the housing base have grooves which together with intermediate spaces between the inner rotor and the outer rotor form the inlet and outlet pump chambers.

6. The gerotor pump as claimed in claim 1, wherein the pressure elements are in each case rotary disks.

7. The gerotor pump as claimed in claim 6, wherein a height of the rotary disks in an axial direction of the outer rotor is smaller than a height of the outer rotor or a height of the housing in an axial direction.

8. The gerotor pump as claimed in claim 6, wherein the rotary disks at least partially separate the housing space in a circumferential direction of the outer rotor and during operation pressure chambers are formed at least between the rotary disks in the circumferential direction.

9. The gerotor pump as claimed in claim 2, wherein the pressure elements are in each case pistons.

10. The gerotor pump as claimed in claim 9, wherein the respective piston seals a radially housing-side end of the opening and, during operation with a radial inner side of the opening, which is connected in fluid terms to the inlet pump chamber and/or to the outlet pump chamber, forms a piston pressure chamber.

11. The gerotor pump as claimed in claim 1, wherein the outer rotor and the housing space have center point axes which are different from each other perpendicularly to the radial direction.

12. A motor/pump unit having: a gerotor pump as claimed in claim 1; and a motor, which is connected to the inner rotor and which is configured to rotate the inner rotor in order to operate the gerotor pump.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0040] Other details, advantages and features of the present invention will be appreciated from the following description of exemplary embodiments with reference to the drawings, in which:

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

[0042] FIG. 2 shows a schematic plan view of the gerotor pump according to the first embodiment of the present invention;

[0043] FIG. 3 shows a perspective detailed view of an outer rotor of the gerotor pump according to the first embodiment of the present invention;

[0044] FIG. 4 shows a perspective detailed view of the outer rotor and a rotary disk of the gerotor pump according to the first embodiment of the present invention;

[0045] FIG. 5 shows a schematic cross sectional view of a gerotor pump according to a second embodiment of the present invention;

[0046] FIG. 6 shows a schematic cross sectional view of a gerotor pump according to a third embodiment of the present invention;

[0047] FIG. 7 shows another schematic sectioned view of the gerotor pump according to the third embodiment of the present invention; and

[0048] FIG. 8 shows a schematic block diagram of a motor/pump unit according to an embodiment of the present invention.

DETAILED DESCRIPTION

[0049] FIG. 1 shows a schematic cross sectional view of a gerotor pump 1 according to a first embodiment of the present invention.

[0050] The gerotor pump 1 (pump 1 below) in order to convey a fluid has a rotatable inner rotor 7 and a rotatable outer rotor 6. The inner rotor 7 is in the form of a gear. The outer rotor 6 is in the form of a toothed ring.

[0051] The inner rotor 7 and the outer rotor 6 are received in a housing space 11 of a housing 10. In this instance, the inner rotor 7 is arranged in a radial direction 15 within the outer rotor 6.

[0052] The inner rotor 7 can be rotated about an inner rotor rotation axis 8, whilst the outer rotor 6 can be rotated about an outer rotor rotation axis 9. As can be seen in FIG. 1, the rotation axes 8, 9 are arranged differently from each other, that is to say, parallel with each other. During operation of the pump 1, a rotation of the inner rotor 7 brings about a rotation of the outer rotor 6. The operation of the pump 1 is explained below with reference to FIG. 2.

[0053] As can further be seen in FIG. 1, the outer rotor 6 in the present embodiment is at least in the idle state of the pump 1 not arranged centrally in the housing space 11. In other words, in this instance center point axes of the housing space 11 and the outer rotor 16 are different from each other. In this instance, the inner rotor 7 is arranged centrally in the housing space 11 so that a center point axis of the housing space 11 coincides with the inner rotor rotation axis 8. The center point axis of the outer rotor 6 coincides in this instance with the outer rotor rotation axis 9.

[0054] The outer rotor 6 has at least two, in this instance eight, openings 16 on the outer circumference 13 thereof. The openings 16 are, as explained below with reference to FIGS. 3 and 4, in this instance slots. The openings 16 are in this instance preferably distributed uniformly over the outer circumference 13 of the outer rotor 6, that is to say, arranged symmetrically. In an alternative specific embodiment, the openings 16 may be arranged asymmetrically along the outer circumference 13 so that between at least two pairs of openings 16 different spacings are formed along the outer circumference 13.

[0055] A rotary disk 12 is arranged in each opening as a pressure element. The rotary disks 12 can be radially displaced inside the respective openings 16. When the outer rotor 6 is rotated, a centrifugal force which results from the rotation results in the rotary disks 12 protruding from the respective openings 12 and bearing on the housing 12.

[0056] As explained below (see FIG. 2), during operation of the pump 1 the fluid which is intended to be conveyed is also located partially in the housing space 11 between the outer rotor 6 and the inner rotor 7. When the outer rotor 6 is rotated, the rotary disks 12 form pressure chambers 14. The pressure chambers 14 are in this instance formed in a radial direction 15 between the outer rotor 7 and the housing 10 and in a circumferential direction 18 between the rotary disks 10.

[0057] As a result of an eccentric rotation of the outer rotor 6 within the housing space 11, pressure chambers 14 with different fluid pressures are formed. These different fluid pressures at various circumferential locations around the outer rotor 6 produce a resultant force which urges the outer rotor 6 against the inner rotor 7. In this instance, the resultant force advantageously results in the outer rotor 6 being pressed in an illustrated-y direction against the inner rotor 7. A gap between opposing tips 19 of the outer rotor 6 and the inner rotor 7 is thereby advantageously reduced. At the locations of the opposing tips 19, a reduction of the gap between the outer rotor 6 and inner rotor 7 has the greatest advantageous effect of reducing an inner leakage and increasing the degree of efficiency of the pump 1. This is further explained with reference to FIG. 2.

[0058] Furthermore, the fluid is located partially inside the respective opening 16 radially further inward than the respective rotary disk 12. In this instance, the fluid is located in an opening space 24 between a radially inner side 17 of the opening 16 and the rotary disk 12 so that opening space/pressure chambers 25 are formed. The opening space/pressure chambers 25 ensure a resilience of the rotary disks 12 and, as explained below with reference to embodiment two, another (urging) force of the outer rotor 6. Alternatively or additionally, there may be arranged in the respective opening space 24 a resilient element which pretensions/urges the rotary disk 12 in a resilient or radial manner.

[0059] FIG. 2 shows a schematic plan view of the gerotor pump 1 according to the first embodiment of the present invention. In this instance, FIG. 2 shows in particular a housing cover 20 which covers the outer rotor 6, the inner rotor 7 and the housing space 11. The components which are covered by the housing cover 20 are in this instance illustrated with broken lines. For greater clarity, the rotary disks 12 are not illustrated in FIG. 2.

[0060] More specifically, the pump 1 has a housing cover 20 and a housing base 21, wherein the housing base 21 is not (directly) visible in the present view. The inner rotor 7 and the outer rotor 6 are arranged, in an axial direction 30 of the outer rotor 6 which coincides with the outer rotor rotation axis 9 (in this instance in the z direction), between the housing cover 20 and the housing base 21. In this instance, at least between the housing cover 20 (and/or at least the housing base 21) and the outer rotor 6 and the inner rotor 7 in the axial direction 30 a spacing (axial gap) is formed so that fluid surrounds the outer rotor 6 and the inner rotor 7.

[0061] Openings for an inlet 2 and for an outlet 4 are formed in the housing base 1. The fluid is conveyed by the pump 1 from the inlet 2 to the outlet 4. As can further be seen in FIG. 2, the housing cover 20 has grooves 22 which extend in the circumferential direction 18 and which in each case are connected to the inlet 2 or the outlet 4. The grooves 22 define together with intermediate spaces 23 between the teeth of the inner rotor 7 and the outer rotor 9 (referred to as the volumes 23 below) 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 comprise the above-mentioned fluid or fluid volume in an axial direction 30 between the housing cover 20 and/or housing base 21 and the outer rotor 6 and the inner rotor 7.

[0062] During operation of the pump 1, fluid is conveyed from the inlet 2 to the outlet 4 in the circumferential direction 18. As can be seen in FIG. 2, the volumes 23 of the intermediate spaces starting from the inlet 2 in the circumferential direction 18 (in this instance in a clockwise direction) initially become greater so that fluid is drawn from the inlet 2. Subsequently, at the end of the groove 22 in the circumferential direction 18, the volumes 23 initially remain almost constant, before the volumes 23 subsequently become smaller. As a result of the reduction of the volumes 23 in the direction toward the outlet 4, the fluid is acted on with pressure and the fluid is conveyed out of the outlet 4. The resulting pressure regions of the fluid, by means of which the fluid is conveyed mainly between the inlet 2 and outlet 4, are also referred to as primary pressure regions, whilst the pressure regions which are formed by the rotary disks 12 explained above are also referred as secondary pressure regions.

[0063] At the locations of the opposing tips 19, a separation of the volumes 23 and consequently a degree of efficiency of the pump 1 as a result of the small contact surfaces of the teeth is particularly sensitive with respect to production tolerances and with respect to an urging of the outer rotor 6 at high pressures of the fluid. As a result of the urging of the outer rotor 6 against the inner rotor 7, brought about by the rotary disks 12 explained with respect to FIG. 1, whereby a gap between the opposing tips is reduced, the degree of efficiency of the pump 1 is increased.

[0064] FIG. 3 shows a perspective detailed view of the outer rotor 6 of the gerotor pump 1 according to the first embodiment of the present invention. As can be seen in FIG. 3, the outer rotor 6 is substantially a toothed ring with slots as openings 16 for receiving the rotary disks 12.

[0065] Furthermore, the outer rotor 6 has a plurality of outer rotor grooves 26, which are formed in the circumferential direction 18 between the openings 16. As a result of the outer rotor grooves 26, a viscous friction with the fluid between the outer rotor 6 and the housing cover 20 and/or the housing base 21 is reduced.

[0066] FIG. 4 shows a perspective detailed view of the outer rotor 6 and a rotary disk 12 of the gerotor pump 1 according to the first embodiment of the present invention. In FIG. 4, the housing base 21 is further illustrated.

[0067] As can be seen in FIG. 4, the rotary disk 12 is positioned on the housing base 21. A height 27 of the rotary disk 12 is with respect to the axial direction 30 smaller than a height 28 of the outer rotor 6. In this instance, the height 27 of the rotary disk 12 is in specific embodiments between 90% and 98% of the height 28 of the outer rotor 6.

[0068] As a result of the smaller height 27 of the rotary disk 12, fluid, indicated by a fluid flow 29, can flow particularly easily from the inlet pump chamber 3 on the rotary disk 12 into the housing space 11 between the outer rotor 6 and housing 10. In this instance, in particular the above-mentioned fluid between the housing cover 20 and the outer rotor 6 and inner rotor 7 (in the axal gap) can flow particularly easily into the housing space 11, that is to say, with little viscous friction.

[0069] In this instance, the rotary disk 12 further has a rounded side face 31 on the housing, whereby a friction between the rotary disk 12 and the housing 10 is reduced.

[0070] FIG. 5 shows a schematic cross sectional view of a gerotor pump 1 according to a second embodiment of the present invention.

[0071] In the present embodiment, the pressure elements are in the form of a piston 32. In this instance, the gerotor pump 1 has at least two, in this instance six, pistons 32. The openings 16 are in the form of radial holes 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 connected in fluid terms to the inlet pump chamber 3 and/or to the outlet pump chamber 5. To this end, the openings 16, as illustrated in FIG. 5, have another axial hole (depth direction in FIG. 5) which is connected to the radial hole. An L-shaped hole is thereby substantially produced in the outer rotor 6, wherein the respective piston 32 is arranged in the radial hole. The fluid which is between the housing cover 20 and the outer rotor 6 (in the axial gap) can thereby flow through the axial portion of the holes in the openings 6. In other words, the axial hole is connected to the axial gap in fluid terms.

[0072] Between the radially inner side 17 of the opening 16 and the respective piston 32 piston pressure chambers 33 are thereby formed. When the outer rotor 6 is rotated, the pistons 32 are pressed radially into the openings 16, wherein the fluid is acted on with pressure by the piston 32. This pressure which is produced applies a force to the radial inner side 17 of the opening 16 and consequently to the outer rotor 6, whereby this rotor is urged against the inner rotor 7. The piston pressure chambers 33 are, in a similar manner to the pressure chambers 14 which are produced by the rotary disks 12, secondary pressure regions.

[0073] As shown by comparing FIG. 5 with FIG. 1, the pistons 32 may also produce the pressure chambers 14 between the outer rotor 6 and the housing 10 in the housing space 11. To this end, the pistons 32 may have a corresponding height 27 of the rotary disks 12.

[0074] In the above embodiments, the outer rotor 6 is at least in the idle state of the pump 1 not arranged centrally in the housing space 11. Alternatively, however, the outer rotor 6 may in the idle state of the pump 1 be arranged centrally in the housing space 11. In this instance, a pressure difference between the inlet 2 and the outlet 4 (primary pressure regions) during operation of the pump 1 brings about an urging of the outer rotor 6. This urging, in particular at high pressures, further brings about a non-central arrangement of the outer rotor 6 in the housing space 11 so that even in such a case during operation of the pump 1 the secondary pressure regions are formed. However, these secondary pressure regions at least partially counteract the urging by the primary pressure regions so that the gap between the outer rotor 6 and the inner rotor 7 at least during the operation of the pump 1 is reduced and the degree of efficiency thereof is increased.

[0075] FIGS. 6 and 7 show in each case schematic sectioned views of a gerotor pump 1 according to a third embodiment of the present invention.

[0076] In the present embodiment, as can be seen in particular in FIG. 6, the housing 10 has along the inner circumference 36 thereof a plurality of, in this instance four, openings 37, also referred to as housing openings 37. In each of these housing openings 37, a radially displaceable pressure element is arranged as a rotary disk 35. Each rotary disk 35 bears in this instance, in particular during operation of the gerotor pump 10, in the circumferential direction 18 on at least one inner face 41 of the housing 10 or the housing opening 37.

[0077] Each rotary disk 35 protrudes from a radial inner side 39 of the housing opening 37 and is arranged on the outer rotor 6. As can be seen in particular in FIG. 7, each rotary disk 35 is urged or pretensioned by a resilient element 38, in this instance a leaf spring, against the outer rotor 6.

[0078] As can further be seen in FIG. 7, a height 27 of the rotary disks 35 with respect to the axial direction 39 is smaller than a height 42 of the housing 10. In this instance, the height 27 of the rotary disks 35 is in particular smaller than a height 28 of the outer rotor 6. As in the first embodiment, fluid can thereby flow from the housing space 11 between the housing cover 20 and the housing 10 into the housing opening 37 particularly easily, that is to say, with little viscous friction.

[0079] Preferably, the housing cover 20 or the housing base 21 may have grooves which direct the fluid into the housing opening 37. In this instance, for example, the resilient element 38 may functionally at least partially be replaced by fluid in the housing opening 37 which urges the rotary disk 35 against the outer rotor 6.

[0080] Alternatively or additionally to the grooves in the housing cover 20 or in the housing base 21, the housing 10 may have one or more housing grooves 43 which are illustrated with dashed lines in FIG. 6. This housing groove 43 is an axial recess in the housing 10 and connects two openings 37 to each other so that they are connected to each other in fluid terms. Furthermore, the illustrated housing groove 43 connects the two openings 37 to the housing space 11 so that the openings 37 are connected thereto in fluid terms. A hydraulic pressure which is applied by the fluid from the inlet pump chamber 3 and/or the outlet pump chamber 5 can thereby urge the rotary disks 35 against the outer rotor 6.

[0081] Furthermore, a plurality of housing grooves 43 may be arranged in the housing 10. In the present example of four openings 37, there may be formed in particular two housing grooves 43 which each connect two of the four openings 37 to each other. It is thereby possible, for example, for two of the openings 37 to be connected in fluid terms to the inlet pump chamber 3 and for the other two of the openings 37 to be connected in fluid terms to the outlet pump chamber 5 without them being short-circuited in fluid terms (in pairs).

[0082] The rotary disks 35 of the present embodiment afford the same advantages as the rotary disks 12 of the first embodiment. In other words, the rotary disks 35 produce pressure chambers 14 in the housing space 11 radially between the outer rotor 6 and the housing 10, whereby the outer rotor 6 is urged.

[0083] The gerotor pump 1 according to the present embodiment can be combined with the gerotor pump 1 according to the first and/or second embodiment. In this instance, in particular the rotary disks 35 of the present embodiment, with the exception of the fact that they are arranged in the housing 10, and the associated openings 37 thereof may have similar or identical configurations to the pressure elements 12, 32 and openings 16 of the first two embodiments. For example, the present rotary disks 35 may also be in the form of pistons which urge the outer rotor 6 against the inner rotor 7. This combination can particularly advantageously be combined with the above-mentioned configuration, in which the housing 10 has one or more housing grooves 43, additionally or alternatively to the possible grooves in the housing cover 20 or in the housing base 21.

[0084] The invention further relates to a motor/pump unit 100. This is illustrated in FIG. 8 which shows a schematic block diagram of the motor/pump unit 100 according to an embodiment of the present invention.

[0085] The motor/pump unit 100 has a motor 101 and a gerotor pump 1 according to the above embodiments. The motor 101 is configured to rotate the inner rotor 7 to operate the gerotor pump 1. In this instance, the motor 101 is mechanically connected to the inner rotor 7 by means of a shaft 102 (see also FIG. 2).

[0086] The motor/pump unit 100 has a particularly good degree of efficiency and is less dependent on tolerances.

[0087] In addition to the above written description of the invention, for the additional disclosure thereof reference may explicitly be hereby made to the illustration of the invention in the Figures.

LIST OF REFERENCE NUMERALS

[0088] 1 Gerotor pump [0089] 2 Inlet [0090] 3 Inlet pump chamber [0091] 4 Outlet [0092] 5 Outlet pump chamber [0093] 6 Outer rotor [0094] 7 Inner rotor [0095] 8 Inner rotor rotation axis [0096] 9 Outer rotor rotation axis [0097] 10 Housing [0098] 11 Housing space [0099] 12 Rotary disk [0100] 13 Outer circumference of the outer rotor [0101] 14 Pressure chamber [0102] 15 Radial direction [0103] 16 Opening [0104] 17 Radial inner side [0105] 18 Circumferential direction [0106] 19 Opposing tips [0107] 20 Housing cover [0108] 21 Housing base [0109] 22 Grooves [0110] 23 Intermediate space/volumes [0111] 24 Opening space [0112] 25 Opening space/pressure chamber [0113] 26 Outer rotor groove [0114] 27 Height of the rotary disk [0115] 28 Height of the outer rotor [0116] 29 Fluid flow [0117] 30 Axial direction [0118] 31 Side face [0119] 32 Piston [0120] 33 Piston pressure chamber [0121] 34 Radial housing-side end of the opening [0122] 35 Rotary disk [0123] 36 Inner circumference of the housing [0124] 37 Housing opening [0125] 38 Resilient element [0126] 39 Radial inner side of the housing opening [0127] 40 Radial outer side of the housing opening [0128] 41 Inner face of the housing [0129] 42 Height of the housing [0130] 43 Housing groove [0131] 100 Motor/pump unit [0132] 101 Motor [0133] 102 Shaft