Rotary pump comprising an adjusting device

Abstract

A rotary pump includes: a pump housing having a low-pressure inlet and a high-pressure outlet; a delivery rotor rotatable about a rotational axis and including multiple deliverers distributed over the circumference of the rotor for delivering a fluid from the low-pressure inlet to the high-pressure outlet; and a setting element for adjusting the delivery volume of the pump. The inlet end of the setting element includes a first circumferential portion which extends circumferentially in the rotational direction of the rotor and the axial width of which is smaller than the axial width of the deliverers and a second circumferential portion which adjoins the first circumferential portion in the rotational direction and the axial width of which is greater than the axial width of the first circumferential portion.

Claims

1. A rotary pump having an adjustable delivery volume, the rotary pump comprising: (a) a pump housing having a low-pressure inlet and a high-pressure outlet for a fluid to be delivered; and (b) a delivery rotor arranged such that it is rotatable about a rotational axis in the pump housing and comprising multiple delivery means which are distributed over a circumference of the delivery rotor for delivering the fluid from the low-pressure inlet to the high-pressure outlet; and (c) a setting element which is adapted to be translationally moved back and forth in relation to the pump housing for adjusting the delivery volume of the rotary pump, wherein (d) an inlet end of the setting element comprises: (d1) a first circumferential portion which extends circumferentially in a rotational direction of the delivery rotor and an axial width of which is smaller than an axial width of the delivery means and (d2) a second circumferential portion which adjoins the first circumferential portion in the rotational direction of the delivery rotor and an axial width of which is greater than the axial width of the first circumferential portion, wherein (e) a transition, in the rotational direction of the delivery rotor, from the first circumferential portion to the second circumferential portion is arranged in the low-pressure inlet in each position of the setting element, wherein the first circumferential portion exhibits a circumferential extent which is smaller than a maximum distance between the two outermost delivery means of a total of four adjacent delivery means as measured in the circumferential direction.

2. The rotary pump according to claim 1, wherein the first circumferential portion and the second circumferential portion are each at least partially arranged radially between the delivery rotor and an inlet channel of the low-pressure inlet.

3. The rotary pump according to claim 1, wherein the transition is a collar of the setting element which is parallel to the rotational axis of the delivery rotor.

4. The rotary pump according to claim 1, wherein an outer surface area of the delivery rotor, an inner surface area of the setting element and the axial outer edges of the delivery means define a delivery region of the rotary pump while the rotary pump is in operation, and the delivery region is connected in direct fluid communication with the low-pressure inlet via the first circumferential portion in the radial direction, and the second circumferential portion prevents direct fluid communication between the delivery region and the low-pressure inlet in the radial direction.

5. The rotary pump according to claim 4, wherein the delivery region comprises a low-pressure region into which the fluid to be delivered flows, wherein the first circumferential portion is arranged at the beginning of the low-pressure region in the rotational direction of the delivery rotor and extends over less than 70% of the circumferential extent of the low-pressure region in any position of the setting element.

6. The rotary pump according to claim 5, wherein the first circumferential portion extends over less than 60% of the circumferential extent of the low-pressure region in any position of the setting element.

7. The rotary pump according to claim 1, wherein the setting element comprises a first sealing sliding surface, which is in sliding contact with the pump housing and is provided next to the first circumferential portion, and a second sealing sliding surface which is in sliding contact with the pump housing and is provided next to the second circumferential portion, wherein the first sealing sliding surface and the second sealing sliding surface slide along the pump housing when the setting element is translationally adjusted.

8. The rotary pump according to claim 7, wherein the first sealing sliding surface defines a first imaginary plane, and the second sealing sliding surface defines a second imaginary plane, wherein the first imaginary plane is embodied to be parallel to the second imaginary plane, and both planes extend between the rotational axis of the delivery rotor and the transition in each position of the setting element.

9. The rotary pump according to claim 8, wherein the first imaginary plane and the second imaginary plane neither intersect nor are tangential to the transition from the first circumferential portion to the second circumferential portion.

10. The rotary pump according to claim 1, wherein the first circumferential portion is formed by a radially continuous, axial recess in the setting element.

11. The rotary pump according to claim 1, wherein the axial width of the second circumferential portion corresponds to or is smaller than the axial width of the delivery means.

12. A rotary pump having an adjustable delivery volume, the rotary pump comprising: (a) a pump housing having a low-pressure inlet and a high-pressure outlet for a fluid to be delivered; and (b) a delivery rotor arranged such that it is rotatable about a rotational axis in the pump housing and comprising multiple delivery means which are distributed over a circumference of the delivery rotor for delivering the fluid from the low-pressure inlet to the high-pressure outlet; and (c) a setting element which is adapted to be translationally moved back and forth in relation to the pump housing for adjusting the delivery volume of the rotary pump, wherein (d) an inlet end of the setting element comprises: (d1) a first circumferential portion which extends circumferentially in a rotational direction of the delivery rotor and an axial width of which is smaller than an axial width of the delivery means and (d2) a second circumferential portion which adjoins the first circumferential portion in the rotational direction of the delivery rotor and an axial width of which is greater than the axial width of the first circumferential portion, wherein (e) a transition, in the rotational direction of the delivery rotor, from the first circumferential portion to the second circumferential portion is arranged in the low-pressure inlet in each position of the setting element, wherein the setting element comprises a first sealing sliding surface, which is in sliding contact with the pump housing and is provided next to the first circumferential portion, and a second sealing sliding surface which is in sliding contact with the pump housing and is provided next to the second circumferential portion, wherein the first sealing sliding surface and the second sealing sliding surface slide along the pump housing when the setting element is translationally adjusted, and wherein the first sealing sliding surface comprises a first sealing edge at an end facing the second sealing sliding surface, and the second sealing sliding surface comprises a second sealing edge at an end facing the first sealing sliding surface, and each of the first sealing edge and the second sealing edge each seal off the low-pressure inlet at the transition in the sliding contact between the pump housing and the setting element, wherein the transition exhibits a distance from each of the first sealing edge and the second sealing edge as measured in the circumferential direction, in the rotational direction of the delivery rotor, which is greater than or equal to a maximum distance between two adjacent delivery means as measured in the circumferential direction in the rotational direction of the delivery rotor.

13. A rotary pump having an adjustable delivery volume, the rotary pump comprising: (a) a pump housing having a low-pressure inlet and a high-pressure outlet for a fluid to be delivered; and (b) a delivery rotor arranged such that it is rotatable about a rotational axis in the pump housing and comprising multiple delivery means which are distributed over a circumference of the delivery rotor for delivering the fluid from the low-pressure inlet to the high-pressure outlet; and (c) a setting element which is adapted to be translationally moved back and forth in relation to the pump housing for adjusting the delivery volume of the rotary pump, wherein (d) an inlet end of the setting element comprises: (d1) a first circumferential portion which extends circumferentially in a rotational direction of the delivery rotor and an axial width of which is smaller than an axial width of the delivery means and (d2) a second circumferential portion which adjoins the first circumferential portion in the rotational direction of the delivery rotor and an axial width of which is greater than the axial width of the first circumferential portion, wherein (e) a transition, in the rotational direction of the delivery rotor, from the first circumferential portion to the second circumferential portion is arranged in the low-pressure inlet in each position of the setting element, wherein the setting element comprises a first sealing sliding surface, which is in sliding contact with the pump housing and is provided next to the first circumferential portion, and a second sealing sliding surface which is in sliding contact with the pump housing and is provided next to the second circumferential portion, wherein the first sealing sliding surface and the second sealing sliding surface slide along the pump housing when the setting element is translationally adjusted, and wherein the first sealing sliding surface comprises a first sealing edge at an end facing the second sealing sliding surface, and the second sealing sliding surface comprises a second sealing edge at an end facing the first sealing sliding surface, and each of the first sealing edge and the second sealing edge each seal off the low-pressure inlet at the transition in the sliding contact between the pump housing and the setting element, and wherein the transition exhibits a distance from the first sealing edge as measured in the circumferential direction, in the rotational direction of the delivery rotor, which is greater than or equal to a distance from the second sealing edge as measured in the circumferential direction.

14. A rotary pump according having an adjustable delivery volume, the rotary pump comprising: (a) a pump housing having a low-pressure inlet and a high-pressure outlet for a fluid to be delivered; and (b) a delivery rotor arranged such that it is rotatable about a rotational axis in the pump housing and comprising multiple delivery means which are distributed over a circumference of the delivery rotor for delivering the fluid from the low-pressure inlet to the high-pressure outlet; and (c) a setting element which is adapted to be translationally moved back and forth in relation to the pump housing for adjusting the delivery volume of the rotary pump, wherein (d) an inlet end of the setting element comprises: (d1) a first circumferential portion which extends circumferentially in a rotational direction of the delivery rotor and an axial width of which is smaller than an axial width of the delivery means and (d2) a second circumferential portion which adjoins the first circumferential portion in the rotational direction of the delivery rotor and an axial width of which is greater than the axial width of the first circumferential portion, wherein (e) a transition, in the rotational direction of the delivery rotor, from the first circumferential portion to the second circumferential portion is arranged in the low-pressure inlet in each position of the setting element, wherein the first circumferential portion and the second circumferential portion exhibit a circumferential extent which corresponds to at least a maximum distance between two adjacent delivery means as measured in the circumferential direction in the rotational direction of the delivery rotor.

15. A rotary pump having an adjustable delivery volume, the rotary pump comprising: (a) a pump housing having a low-pressure inlet and a high-pressure outlet for a fluid to be delivered; and (b) a delivery rotor arranged such that it is rotatable about a rotational axis in the pump housing and comprising multiple delivery means which are distributed over a circumference of the delivery rotor for delivering the fluid from the low-pressure inlet to the high-pressure outlet; and (c) a setting element which is adapted to be translationally moved back and forth in relation to the pump housing for adjusting the delivery volume of the rotary pump, wherein (d) an inlet end of the setting element comprises: (d1) a first circumferential portion which extends circumferentially in a rotational direction of the delivery rotor and an axial width of which is smaller than an axial width of the delivery means and (d2) a second circumferential portion which adjoins the first circumferential portion in the rotational direction of the delivery rotor and an axial width of which is greater than the axial width of the first circumferential portion, wherein (e) a transition, in the rotational direction of the delivery rotor, from the first circumferential portion to the second circumferential portion is arranged in the low-pressure inlet in each position of the setting element, wherein the first circumferential portion is formed by a radially continuous, axial recess in the setting element, and wherein the axial recess comprises a recess base which is delineated in the circumferential direction by two opposing recess walls, and one of the recess walls forms the transition.

16. A rotary pump having an adjustable delivery volume, the rotary pump comprising: (a) a pump housing having a low-pressure inlet and a high-pressure outlet for a fluid to be delivered; and (b) a delivery rotor arranged such that it is rotatable about a rotational axis in the pump housing and comprising multiple delivery means which are distributed over a circumference of the delivery rotor for delivering the fluid from the low-pressure inlet to the high-pressure outlet; and (c) a setting element which is adapted to be translationally moved back and forth in relation to the pump housing for adjusting the delivery volume of the rotary pump, wherein (d) an inlet end of the setting element comprises: (d1) a first circumferential portion which extends circumferentially in a rotational direction of the delivery rotor and an axial width of which is smaller than an axial width of the delivery means and (d2) a second circumferential portion which adjoins the first circumferential portion in the rotational direction of the delivery rotor and an axial width of which is greater than the axial width of the first circumferential portion, wherein (e) a transition, in the rotational direction of the delivery rotor, from the first circumferential portion to the second circumferential portion is arranged in the low-pressure inlet in each position of the setting element, wherein the axial width of the second circumferential portion corresponds to or is smaller than the axial width of the delivery means, wherein the second circumferential portion comprises a cavity which is radially open towards the delivery rotor and is not axially continuous, and the cavity exhibits a circumferential extent, from the first circumferential portion in the rotational direction of the delivery rotor, which at most corresponds to a maximum distance between two adjacent delivery means as measured in the circumferential direction.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The features described above can be combined with each other as desired, wherever technically expedient and suitable. Other features, combinations of features and advantages of aspects of the invention follow from the following description of example embodiments on the basis of the figures. There is shown:

(2) FIG. 1 a sectional representation of an example embodiment of the rotary pump in accordance with the invention;

(3) FIG. 2 a perspective representation of the sectional representation shown in FIG. 1;

(4) FIG. 3 a perspective representation of a setting element of the example embodiment shown in FIG. 1;

(5) FIG. 4 a plan view of the setting element shown in FIG. 3;

(6) FIG. 5 a first sectional representation of the setting element shown in FIG. 3;

(7) FIG. 6 a second sectional representation of the setting element shown in FIG. 3; and

(8) FIG. 7 a detail of a lateral view of the example embodiment shown in FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

(9) FIG. 1 is a sectional representation of an example embodiment of the rotary pump 1 in accordance with the invention. In the example embodiment, the rotary pump 1 is embodied as a vane pump. The rotary pump 1 comprises a pump housing 2 comprising a low-pressure inlet 3 and a high-pressure outlet 4 for the fluid to be delivered. In order to channel the fluid to be delivered into the interior of the rotary pump 1, the low-pressure inlet 3 comprises a fluid port 3a on an outer wall of the pump housing 2. The fluid port 3a forms an inlet intersection for an inlet channel 3b of the low-pressure inlet 3. The inlet channel 3b extends from the fluid port 3a into the pump housing 2. Similarly, the high-pressure outlet 4 comprises an outlet channel 4a in order to channel the fluid out of the rotary pump via a fluid port (not shown) of the high-pressure outlet 4.

(10) A delivery rotor 5, which can be rotated about a rotational axis D, is arranged within the pump housing 2. The delivery rotor 5 is axially delineated by the pump housing 2. Multiple delivery means 6 are distributed over the circumference of the delivery rotor 5. In the example embodiment shown, the delivery means 6 can be moved back and forth radially outwards and inwards in relation to the rotational axis D. The delivery means 6 are arranged at equal distances from each other in the circumferential direction. Alternatively, or additionally, the delivery means 6 can be arranged at different distances from each other in the circumferential direction, at least in portions. The movement of the delivery means 6 is delineated radially inwards by the delivery rotor 5. The movement of the delivery means 6 outwards, away from the rotational axis D, is delineated by an inner surface area 16 of a setting element 10.

(11) While the rotary pump 1 is in operation, the delivery rotor 5 rotates about the rotational axis D, wherein the delivery means 6 are pressed radially outwards towards the inner surface area 16 of the setting element 10 by the centrifugal force acting on the delivery means 6. The axial outer edges of the delivery means 6, together with the outer surface area 5a of the delivery rotor 5 and the inner surface area 16 of the setting element 10, define a delivery region. The delivery region is thus an annular volume, the axial width of which corresponds to the width of the delivery means 6. Within the delivery region, each two adjacent delivery means 6 form a delivery cell 6a. The fluid to be delivered is supplied to the delivery region and/or the delivery cells 6a via the low-pressure inlet 3, in particular via the fluid port 3a and the inlet channel 3b. In the delivery region, the fluid to be delivered is delivered from the low-pressure inlet 3 to the high-pressure outlet 4, in particular to the outlet channel 4a. The fluid to be delivered is delivered from the low-pressure inlet 3 to the high-pressure outlet 4, through the delivery region, in the delivery cells 6a due to the direct influence of the rotating delivery means 6.

(12) The setting element 10, the detailed structure of which is described in more detail further below and on the basis of FIGS. 3 to 6, is embodied to alter and/or adjust the delivery volume of the rotary pump 1. For this purpose, the setting element 10 can be moved back and forth between at least two positions in relation to the pump housing 2. In the example embodiment, the setting element 10 can be translationally moved, i.e. the setting element 10 is arranged such that it can be shifted in the pump housing 2. The inner surface area 16 of the setting element 10 extends around a central axis (not shown) which is offset in parallel in relation to the rotational axis D of the delivery rotor 5 when the setting element 10 is in a first position. Because the central axis of the setting element 10 is offset in parallel in relation to the rotational axis D of the delivery rotor 5, the setting element 10 exhibits an eccentricity in relation to the delivery rotor 5. FIG. 1 shows the setting element 10 in its first position.

(13) In the first position, the delivery region comprises a low-pressure region in which the volume of the delivery cells 6a increases in the rotational direction of the delivery rotor 5. When the setting element 10 is in its first position, the delivery region also comprises a high-pressure region which adjoins the low-pressure region in the rotational direction of the delivery rotor 5. In the high-pressure region, the volume of the delivery cells 6a decreases in the rotational direction of the delivery rotor 5. The rotary pump 1 exhibits a maximum delivery volume in the first position.

(14) In a second position (not shown), the setting element 10 is shifted in the pump housing 2 such that the setting element 10 exhibits a minimum eccentricity or no eccentricity in relation to the delivery rotor 5. In other words, the central axis of the setting element 10 is substantially or almost coaxial with the rotational axis D of the delivery rotor 5 in the second position. The rotary pump 1 exhibits a minimum delivery volume in the second position.

(15) The first position and second position are preferably end positions of the setting element 10, i.e. the setting element 10 cannot assume a position in which it exhibits a greater eccentricity in relation to the delivery rotor 5 than in the first position and/or a smaller eccentricity in relation to the delivery rotor 5 than in the second position. The setting element 10 can assume multiple intermediate positions, for example any number of intermediate positions, between the first position and the second position.

(16) The rotary pump 1 comprises a restoring means 7 in order to press the setting element 10 into the first position. The restoring means 7 preferably exerts a restoring force on the setting element 10, wherein the restoring force presses the setting element 10 into the first position. In the example embodiment shown, the restoring means 7 comprises two restoring springs 7 which are supported on the one hand on the pump housing 2 and on the other hand on a respective pressure surface 21 of the setting element 10. In order to move the setting element 10 into the second position, the rotary pump 1 comprises a pressure channel 23 and a pressure chamber 24. The pressure chamber 24 extends between the pump housing 2 and the setting element 10. A pressurized fluid can be channeled into the pressure chamber 24 via the pressure channel 23. The fluid pressure thus prevailing in the pressure chamber 24 presses the setting element 10 towards the second position, against the restoring force of the restoring means 7. The pressurized fluid can for example be the delivered fluid, which is taken at a point of the high-pressure region still within the pump housing 2 or a point downstream of the high-pressure outlet 4.

(17) At the inlet end, i.e. in the region of the low-pressure inlet 3, the setting element 10 comprises a first circumferential portion 11 and a second circumferential portion 13. Irrespective of this, the delivery region is delineated or surrounded on the radially outer side, at least in portions, by the first circumferential portion 11 and the second circumferential portion 13. The second circumferential portion 13 adjoins the first circumferential portion 11 in the rotational direction of the delivery rotor 5. Both circumferential portions 11, 13 extend radially between the inner surface area 16 and an outer surface area 17 of the setting element 10.

(18) The first circumferential portion 11 exhibits an axial width B.sub.1 which is smaller than the axial width of the delivery means 6. In FIG. 13, one of the delivery means 6 of width B.sub.6 is shown to the left of the setting element 10. The second circumferential portion 13 exhibits an axial width B.sub.2 which is greater than the axial width B.sub.1 of the first circumferential portion 11 (cf. FIGS. 3 and 5). The axial width B.sub.2 of the second circumferential portion 13 preferably corresponds to the axial width B.sub.6 of the delivery means 6.

(19) An extent of the first circumferential portion 11 as measured in the circumferential direction is greater than or equal to the circumferential extent of the second circumferential portion 13. In the example embodiment shown in FIG. 1, the extent of the first circumferential portion 11 as measured in the circumferential direction is greater than the circumferential extent of the second circumferential portion 13.

(20) As shown in FIG. 1, the extent of the first circumferential portion 11 as measured in the circumferential direction is greater than the maximum circumferential extent of two adjacent delivery cells 6a. In other words, the extent of the first circumferential portion 11 as measured in the circumferential direction is greater than the maximum circumferential distance between the two outermost delivery means 6 of a total of three adjacent delivery means 6. Irrespective of this, the extent of the first circumferential portion 11 as measured in the circumferential direction is smaller than the maximum circumferential extent of three adjacent delivery cells 6a. The extent of the first circumferential portion 11 as measured in the circumferential direction is smaller than the maximum circumferential distance between the two outermost delivery means 6 of a total of four adjacent delivery means 6.

(21) The extent of the second circumferential portion 13 as measured in the circumferential direction is greater than the maximum circumferential extent of a delivery cell 6a. In other words, the extent of the second circumferential portion 13 as measured in the circumferential direction is greater than the maximum circumferential distance between two adjacent delivery means 6. Irrespective of this, the extent of the second circumferential portion 13 as measured in the circumferential direction is smaller than the maximum circumferential extent of two adjacent delivery cells 6a. The extent of the second circumferential portion 13 as measured in the circumferential direction is smaller than the maximum circumferential distance between the two outermost delivery means 6 of a total of three adjacent delivery means 6.

(22) While the rotary pump 1 is in operation, the fluid to be delivered can flow around the first circumferential portion 11 in the radial direction in order to radially flow into the delivery region of the rotary pump 1. The delivery region of the rotary pump 1 is connected in direct fluid communication with the low-pressure inlet 3, in particular the inlet channel 3a of the low-pressure inlet 3, via the first circumferential portion 11 in the radial direction. The first circumferential portion 11 advantageously causes the delivery cells 6a to be optimally flooded with the fluid to be delivered at the beginning of the low-pressure region, in particular in a first portion of the low-pressure region.

(23) The first circumferential portion 11 is formed by a recess 12, in particular an axial recess 12, in the setting element 10. The recess 12 is continuous in the radial direction.

(24) The first circumferential portion 11 extends in the rotational direction of the delivery rotor 5 up to a transition 15. In the example embodiment, the transition 15 is a collar 15 and can in particular be a collar 15 which is parallel to the rotational axis D of the delivery rotor 5. The transition 15 connects the first circumferential portion 11 to the second circumferential portion 13. In other words, the transition 15 defines the boundary between the first circumferential portion 11 and the second circumferential portion 13. In the example embodiment shown, the transition 15 is arranged in the low-pressure inlet 3 in any position of the setting element 10. The transition 15 is arranged within the range of extent of the low-pressure inlet 3 as measured in the circumferential direction in any position of the setting element 10, and the fluid flowing in the low-pressure inlet 3 can preferably flow onto it in any position of the setting element 10. The transition 15 is arranged radially between the delivery rotor 5 and a portion of the low-pressure inlet 3, in particular the inlet channel 3b, in any position of the setting element 10.

(25) The fluid to be delivered, which flows into the delivery cells 6a even at the beginning of the low-pressure region while the rotary pump 1 is in operation, is subjected to a centrifugal force which increases in the rotational direction of the delivery rotor 5 because it is carried off by the delivery means 6. This centrifugal force acting on the fluid causes the fluid to be pressed radially outwards with increasing force in the rotational direction of the delivery rotor 5. Further flooding of the delivery cells 6a from a radial direction is increasingly impeded in the rotational direction of the delivery rotor 5. Instead, the fluid even tends to be pressed back out of the delivery cells 6a. This effect occurs in particular towards the end of the low-pressure region, i.e. in particular in a second circumferential portion 13 of the low-pressure region or setting element 10 which adjoins the first circumferential portion 11 in the rotational direction of the delivery rotor 5.

(26) The second circumferential portion 13 is shaped such that a radial flow of the fluid out of the delivery cells 6a is impeded or advantageously prevented. In other words, the second circumferential portion 13 impedes or prevents direct fluid communication between the delivery region and the low-pressure inlet 3, in particular the inlet channel 3b of the low-pressure inlet 3, in the radial direction. To this end, the axial width B.sub.2 of the second circumferential portion 13 corresponds at least substantially to the axial width B.sub.6 of the delivery means 6 in advantageous embodiments.

(27) In the example embodiment, the second circumferential portion 13 comprises a cavity 14. The cavity 14 is an axial recess in the second circumferential portion 13. The cavity 14 is open radially inwards, i.e. towards the inner surface area 16 of the setting element 10, and is delineated on the radially outer side by an outer wall of the setting element 10. The setting element 10 axially drops incrementally from the delineating outer wall onto a base of the cavity 14, such that the strip-shaped cavity 14 around the delivery means 6 which pass on the inside is obtained over the length of the second circumferential portion 13 as measured in the circumferential direction.

(28) The cavity 14 extends in the circumferential direction, counter to the rotational direction of the delivery rotor 5, up to the first circumferential portion 11. The cavity 14 is delineated in the rotational direction of the delivery rotor 5 by a wall 14a.

(29) The fluid to be delivered can flow from the low-pressure inlet 3 into the cavity 14 via the first circumferential portion 11. The fluid situated in the cavity 14 mainly exhibits a tangential flow direction in relation to the delivery rotor 5. The delivery means 6 which rotate past the cavity 14 accelerate the fluid situated in the cavity 14 in the rotational direction of the delivery rotor 5. However, an outer wall of the setting element 10 which delineates the cavity 14 on the radially outer side holds the fluid back. The fluid accelerated in the cavity 14 is then directed into the delivery region, in particular into the low-pressure region, of the rotary pump 1 in the region of the wall 14a. The cavity 14 enables indirect fluid communication between the delivery region and the low-pressure inlet 3 via the second circumferential portion 13. The filling of the delivery cells 6a in the second circumferential portion 13 is improved by the cavity 14 which is delineated on the radially outer side by the outer wall of the setting element 10.

(30) The rotary pump 1 comprises a flow channeling structure 22 which is arranged in the low-pressure inlet 3. The flow channeling structure 22 protrudes axially, in relation to the rotational axis D of the delivery rotor 5, from a wall of the pump housing 2 into the low-pressure inlet 3. The flow channeling structure 22 is preferably embodied to influence the fluid flow flowing in the low-pressure inlet 3, in particular the fluid flowing in the inlet channel 3b. In the example embodiment, the fluid flow is at least partially redirected by the flow channeling structure 22. A first sub-flow of the fluid is redirected and/or deflected by the flow channeling structure 22 in such a way that the first sub-flow obtains at least a flow direction component which is opposite to the rotational direction of the delivery rotor 5. A second sub-flow of the fluid is redirected and/or deflected by the flow channeling structure 22 in such a way that the second sub-flow obtains at least a flow component which corresponds to the rotational direction of the delivery rotor 5.

(31) The flow channeling structure 22, together with the pump housing 2, forms a first inlet sub-channel 3c which is axially open on one side. The first sub-flow of the fluid flow preferably flows through the first inlet sub-channel 3c while the rotary pump 1 is in operation. A second inlet sub-channel 3d is arranged next to the first inlet sub-channel 3c in the rotational direction of the delivery rotor 5. The second inlet sub-channel 3d is axially open on one side and is formed by the flow channeling structure 22 and the pump housing 2. The second sub-flow of the fluid preferably flows through the second inlet sub-channel 3d while the rotary pump 1 is in operation. In other words, the flow channeling structure 22 protrudes axially into the low-pressure inlet 3 such that it is arranged between the first inlet sub-channel 3c and the second inlet sub-channel 3d. The flow channeling structure 22 separates the first inlet sub-channel 3c from the second inlet sub-channel 3d in the circumferential direction.

(32) The flow channeling structure 22 protrudes axially from only one side of the pump housing 2 into the low-pressure inlet 3, i.e. it does not extend over the full axial width of the low-pressure inlet 3. Fluid can therefore also flow across the flow channeling structure 22. The flow channeling structure 22 could however in principle also axially extend almost completely through the low-pressure inlet 3.

(33) The first circumferential portion 11 is arranged axially next to and/or in the first inlet sub-channel 3c in any position of the setting element 10. The second circumferential portion 13 is arranged axially next to and/or in the second inlet sub-channel 3d in any position of the setting element 10. The transition 15 is arranged axially next to the flow channeling structure 22 and/or axially next to the second inlet sub-channel 3d in any position of the setting element 10. Alternatively, or additionally, the transition 15 can be arranged radially next to the flow channeling structure 22 and/or in the second inlet sub-channel 3d in any position of the setting element 10.

(34) For translationally adjusting the setting element 10, the setting element 10 comprises multiple sealing sliding surfaces 18, 19. Each sealing sliding surface 18, 19 respectively abuts a sliding surface 8, 9 of the pump housing 2. If the setting element 10 is adjusted, the sealing sliding surfaces 18, 19 slide along the respective sliding surface 8, 9. The sealing sliding surfaces 18, 19 comprise sealing edges 18a, 19a which face the low-pressure inlet 3. The sealing edges 18a, 19a seal off the low-pressure inlet 3 at the transition from the pump housing 2 to the setting element 10.

(35) In the example embodiment shown in FIG. 1, the setting element 10 comprises a first sealing sliding surface 18 comprising a first sealing edge 18a (FIG. 3). The first sealing sliding surface 18 abuts a first sliding surface 8 of the pump housing 2. A second sealing sliding surface 19 of the setting element 10 comprises a second sealing edge 19a. The second sealing sliding surface 19 abuts a second sliding surface 9 of the pump housing 2. The first sealing sliding surface 18 is arranged circumferentially next to the first circumferential portion counter to the rotational direction of the delivery rotor 5. The second sealing sliding surface 19 is arranged circumferentially next to the second circumferential portion 13 in the rotational direction of the delivery rotor 5.

(36) The transition 15 has a distance from the first sealing edge 18a as measured in the circumferential direction which is greater than or equal to a distance from the second sealing edge 19a as measured in the circumferential direction. In the example embodiment shown in FIG. 1, the distance between the transition 15 and the first sealing edge 18a as measured in the circumferential direction is greater than the distance between the transition 15 and the second sealing edge 19a as measured in the circumferential direction.

(37) The distance between the transition 15 and the first sealing edge 18a as measured in the circumferential direction is greater than the maximum circumferential extent of two adjacent delivery cells 6a. In other words, the distance between the transition 15 and the first sealing edge 18a as measured in the circumferential direction is greater than the maximum circumferential distance between the two outermost delivery means 6 of a total of three adjacent delivery means 6. Irrespective of this, the distance between the transition 15 and the first sealing edge 18a as measured in the circumferential direction is smaller than the maximum circumferential extent of three adjacent delivery cells 6a. The distance between the transition 15 and the first sealing edge 18a as measured in the circumferential direction is smaller than the maximum circumferential distance between the two outermost delivery means 6 of a total of four adjacent delivery means 6.

(38) The distance between the transition 15 and the second sealing edge 19a as measured in the circumferential direction is greater than the maximum circumferential extent of a delivery cell 6a. In other words, the distance between the transition 15 and the second sealing edge 19a as measured in the circumferential direction is greater than the maximum circumferential distance between two adjacent delivery means 6. Irrespective of this, the distance between the transition 15 and the second sealing edge 19a as measured in the circumferential direction is smaller than the maximum circumferential extent of two adjacent delivery cells 6a. The distance between the transition 15 and the second sealing edge 19a as measured in the circumferential direction is smaller than the maximum circumferential distance between the two outermost delivery means 6 of a total of three adjacent delivery means 6.

(39) The first sealing sliding surface 18 preferably spans a first imaginary plane 18, and the second sealing sliding surface 19 spans a second imaginary plane 19 both shown in FIG. 3. The two imaginary planes 18 and 19 extend parallel to each other in the movement direction of the setting element 10. In the example embodiment, the second imaginary plane 19 is offset in parallel in relation to the first imaginary plane 18. The second imaginary plane 19 in particular exhibits an orthogonal distance from the rotational axis D which is greater than the orthogonal distance between the first imaginary plane 18 and the rotational axis D. In alternative example embodiments, the two planes 18 and 19 can however also be arranged congruently with each other. Both imaginary planes 18 and 19 extend between the rotational axis D of the delivery rotor 5 and the transition 15 in any position of the setting element 10.

(40) For better comprehension, the sectional representation of the rotary pump 1 shown in FIG. 1 is shown in a perspective representation in FIG. 2. For an explanation of the structure and functionality of the rotary pump 1 depicted in FIG. 2, reference is made to the statements made above.

(41) FIG. 3 shows a perspective representation of the setting element 10 of the example embodiment. The setting element 10 can however also be used in other rotary pumps having an adjustable delivery volume. The setting element 10 preferably consists of one part and can in particular be molded in one piece.

(42) The setting element 10 is delineated on the radially outer side by an outer surface area 17 and on the radially inner side by an inner surface area 16. Two pressure surfaces 21 are also embodied on the setting element 10, on each of which a restoring means 7 of the rotary pump 1 can be supported (the restoring means 7 not being shown in FIG. 3). In alternative embodiments, the setting element 10 can also comprise only one pressure surface 21 or more than two pressure surfaces 21.

(43) The first sealing sliding surface 18 and the second sealing sliding surface 19 are visible in the perspective view shown in FIG. 3. The setting element 10 comprises two other sealing sliding surfaces, which are preferably each embodied in a similar way to the first sealing sliding surface 18 and the second sealing sliding surface 19, on the opposite side of the setting element 10, i.e. on the side of the high-pressure outlet.

(44) The edge of the first sealing sliding surface 18 which faces the first circumferential portion 11 forms the first sealing edge 18a. The edge of the second sealing sliding surface 19 which faces the second circumferential portion 13 forms the second sealing edge 19a.

(45) The first circumferential portion 11 exhibits an axial width B.sub.1 which is smaller than the axial width B.sub.2 of the second circumferential portion 13. The first circumferential portion 11 is separated from the second circumferential portion 13 in the circumferential direction by the transition 15.

(46) The first circumferential portion 11 is formed by at least one recess 12 or, as in the example embodiment shown, by two axially opposing recesses 12. The recess 12 comprises a recess base 12a. The edge 12c which connects the outer surface area 17 to the recess base 12a is preferably rounded and/or exhibits a radius. A rounded edge 12c causes a less turbulent radial flow of the fluid to be delivered from the low-pressure inlet 3 into the delivery region of the rotary pump 1. The recess base 12a is respectively delineated in the circumferential direction by a recess wall 12b. The recess wall 12b arranged in the rotational direction of the delivery rotor 5 simultaneously forms the transition 15.

(47) The transition 15 is a collar 15 of the setting element 10. The collar 15 extends perpendicularly from the first circumferential portion 11, in particular from the recess base 12a, in the axial direction.

(48) The second circumferential portion 13, which is adjacent in the rotational direction of the delivery rotor 5, exhibits a width B.sub.2 which corresponds to the axial width B.sub.6 of the delivery means 6. The second circumferential portion 13 comprises a cavity 14 on the side of the inner surface area 16. The cavity 14 extends in the circumferential direction from the first circumferential portion 11 and/or from the transition 15 up to a wall 14a.

(49) In the example embodiment of the setting element 10 shown in FIG. 3, a pressure cavity 25 is provided in the second sealing sliding surface 19. When the setting element 10 is installed, the pressure cavity 25 is connected in fluid communication with the pressure chamber 24 via a channel 26.

(50) For better comprehension, the setting element 10 is shown in a plan view in FIG. 4. FIG. 5 and FIG. 6 show the sections of the setting element 10 indicated in FIG. 4. With regard to the specific structure of the setting element 10, reference is made to the statements made above.

(51) FIG. 7 shows a detail of a lateral view of the rotary pump 1. In the detail shown in FIG. 7, the viewer is looking into the pump housing 2 through the low-pressure inlet 3 in the flow direction of the fluid to be delivered.

(52) The fluid to be delivered enters the inlet channel 3b of the low-pressure inlet 3 via the fluid port 3a. A first part of the inflowing fluid can flow directly, preferably in the radial direction, towards the setting element 10, in particular towards the outer surface area 17 of the setting element 10. The fluid can flow into the delivery region, in particular radially or at least with a radial direction component, via the first circumferential portion 11 and delivered by the delivery means 6.

(53) The second circumferential portion 13 adjoins the first circumferential portion 11 in the rotational direction of the delivery rotor 5. The second circumferential portion 13 exhibits an axial width which corresponds to the axial width of the delivery means 6. The second circumferential portion 13 thus advantageously prevents the fluid to be delivered from being able to flow radially back out of the delivery region due to the increasing centrifugal force.

(54) A second part of the inflowing fluid hits the flow channeling structure 22. The flow channeling structure 22 directs a sub-flow of the second part of the fluid into the first inlet sub-channel 3c. Another sub-flow of the second part of the fluid is directed into the second inlet sub-channel 3d by the flow channeling structure 22.

(55) In the example embodiment, the first circumferential portion 11 is arranged axially next to and in particular also axially above the first inlet sub-channel 3c in any position of the setting element 10. The second circumferential portion 13 is arranged axially next to and in particular also axially above the second inlet sub-channel 3d in any position of the setting element 10. Depending on the position of the setting element 10, the transition 15 is arranged axially next to and in particular axially above either the flow channeling structure 22 and/or the second inlet sub-channel 3d.

REFERENCE SIGNS

(56) TABLE-US-00001 1 rotary pump 2 pump housing 3 low-pressure inlet 3a fluid port 3b inlet channel 3c first inlet sub-channel 3d second inlet sub-channel 4 high-pressure outlet 4a outlet channel 5 delivery rotor 5a outer surface area 6 delivery means 6a delivery cells 7 restoring means 8 first sliding surface 9 second sliding surface 10 setting element 11 first circumferential portion 12 recess 12a recess base 12b recess wall 12c edge 13 second circumferential portion 14 cavity 14a wall 15 transition 16 inner surface area 17 outer surface area 18 first sealing sliding surface 18a first sealing edge 19 second sealing sliding surface 19a second sealing edge 20 21 pressure surface 22 flow channeling structure 23 pressure channel 24 pressure chamber 25 pressure recess 26 channel D rotational axis B.sub.1 axial width B.sub.2 axial width B.sub.6 axial width