EP4160019A1 - Rotary pump with an adjusting device - Google Patents

Abstract

Rotary pump with adjustable delivery volume, the rotary pump having a pump housing with a low-pressure inlet and a high-pressure outlet for a fluid to be delivered, a delivery rotor which is arranged in the pump housing such that it can rotate about an axis of rotation and has a plurality of delivery means distributed over the circumference of the delivery rotor for delivering the fluid from the low-pressure inlet to the high-pressure outlet, and an adjusting element that can be moved back and forth in translation with respect to the pump housing for adjusting the delivery volume of the rotary pump, the adjusting element having a first peripheral section on the inlet side, which extends circumferentially in the direction of rotation of the delivery rotor and whose axial width is smaller than the axial width of the delivery means, and a second peripheral section, which follows the first peripheral section in the direction of rotation of the conveyor rotor and whose axial width is greater than the axial width of the first peripheral section, wherein a transition from the first peripheral section to the second peripheral section is arranged in every position of the actuating element in the low-pressure inlet.

Description

The invention relates to a rotary pump with an adjustable delivery volume. The rotary pump includes a pump housing with a low pressure inlet and a high pressure outlet. A delivery rotor which can be rotated about an axis of rotation is arranged inside the pump housing. The delivery rotor has a plurality of delivery means in order to deliver a fluid to be delivered from the low-pressure inlet to the high-pressure outlet. The conveying means distributed over the circumference of the conveying rotor can in particular be radially movable in relation to the axis of rotation of the conveying rotor. In order to adjust the delivery volume of the rotary pump, an adjusting element that can be moved in a translatory manner is arranged in the pump housing. The actuating element preferably limits the movement of the conveying means radially outwards with an inner lateral surface.

Rotary pumps with an adjustable delivery volume are known from the prior art, in which the adjusting element for adjusting the delivery volume is arranged in the pump housing such that it can rotate and/or swivel with respect to the axis of rotation of the delivery rotor. The actuating element delimits a delivery area of the rotary pump radially on the outside with its inner lateral surface. The adjusting elements of these known rotary pumps inevitably have circumferential sections which are arranged in the low-pressure inlet in every position of the adjusting element. There is always a peripheral section of the actuating element, which is arranged radially between the delivery rotor, in particular the delivery area, and the fluid flowing in via the low-pressure inlet. In order to nevertheless be able to ensure a radial inflow or supply of fluid to the conveying area, said circumferential sections regularly have an axial width which is smaller than the axial width of the conveying means.

The rotary pumps known from the prior art have the disadvantage that the radial inflow decreases in the direction of rotation of the feed rotor. The reason for this is that fluid flowing into the conveying area is carried along and accelerated in the circumferential direction, so that it is exposed to a centrifugal force that increases in the direction of rotation of the conveying rotor and presses radially outward. This effect has a negative influence on the conveying behavior. It can even happen that part of the fluid flows back radially outwards into the low-pressure inlet. This unwanted effect is main depends on the rotational speed of the feed rotor and occurs in all positions of the control element and is particularly disruptive in positions of maximum feed volume.

It is an object of the invention to provide a rotary pump that has improved pumping behavior and can be produced at low cost.

This object is achieved with the features of claim 1. Advantageous developments result from the dependent claims, the description and the figures.

The rotary pump according to the invention comprises a pump housing with a low-pressure inlet and a high-pressure outlet for a fluid to be pumped. A delivery rotor which can be rotated about an axis of rotation is arranged inside the pump housing. The conveying rotor has a plurality of conveying means distributed over the circumference of the conveying rotor, which can be moved, for example, radially or with a radial directional component in relation to the axis of rotation of the conveying rotor. The conveying means can be arranged on a rotor base body of the conveying rotor. In order to adjust the delivery volume of the rotary pump, the rotary pump comprises an adjusting element that can be moved back and forth translationally in relation to the pump housing.

A "translational movement" is understood to mean a change in the position of the corresponding component in relation to the pump housing, in which all components of the component experience the same displacement, i.e. have the same velocity and/or the same acceleration vector at a given point in time.

A "rotary movement" or a "rotary movement" is understood to mean a change in the position of the corresponding component in relation to the pump housing, in which all components of the component move in a circular manner about a common axis.

Preferably, an outer lateral surface of the rotor, in particular an outer lateral surface of the rotor base body, and an inner lateral surface of the actuating element radially delimit a delivery area of the rotary pump. The conveying area can be defined axially by the axial extent of the conveying means. Within the conveying area, two adjacent conveying means can form a conveying cell together with the outer lateral surface of the rotor, in particular the outer lateral surface of the basic rotor body, and the inner lateral surface of the actuating element. The cell volume of a delivery cell preferably changes during operation of the rotary pump (when the delivery rotor rotates). The Delivery area can have a low-pressure area and a high-pressure area. The low-pressure area is defined, for example, by the fact that the cell volume of the conveyor cells increases in the direction of rotation of the conveyor rotor. The high-pressure area is defined, for example, by the fact that the cell volume of the delivery cells decreases in the direction of rotation of the delivery rotor.

The low-pressure inlet preferably extends from a fluid connection on the outer wall of the pump housing up to or into the delivery area, in particular up to or into the low-pressure area. The fluid to be delivered can be supplied to the delivery area via the low-pressure inlet. Irrespective of this, the low-pressure inlet can have a number of sections. For example, an inlet channel can connect to the fluid connection in the direction of flow of the fluid to be delivered. The inlet channel advantageously extends from the fluid connection to an outer lateral surface of the actuating element. The inlet channel can be a passage or channel in the pump housing. From the outer lateral surface of the actuating element, the inlet channel can merge into a feed section. The feed section can have one or more partial channels and/or pockets and/or depressions and/or kidneys in the pump housing. These preferably enable an axial supply of the low-pressure area of the conveying area with the fluid. Irrespective of this, the feed section can also include recesses and/or indentations in other components of the rotary pump, such as the actuating element, in order to enable a supply, in particular a radial supply, of the delivery area, in particular the low-pressure area, with fluid.

The high-pressure outlet extends from the delivery area, in particular from the high-pressure area, to a fluid outlet on the outer wall of the pump housing. The delivered fluid can be discharged from the delivery area, in particular from the high-pressure area, via the high-pressure outlet. Irrespective of this, the high-pressure outlet can have a number of sections. For example, in the direction of flow of the fluid to be delivered, an outlet section can connect to the delivery area, in particular to the high-pressure area. The outlet section can be formed by one or more partial channels, pockets, depressions and/or kidneys in the pump housing. These preferably allow the conveyed fluid to be discharged axially from the conveying area, in particular from the high-pressure area. Irrespective of this, the outlet section can also include recesses and/or indentations in other components of the rotary pump, such as the actuating element, in order to allow the fluid to be discharged, in particular radially, from the delivery area, in particular from the high-pressure area. From the outer surface of the actuator can Outlet area merge into an outlet channel. The outlet channel advantageously extends from the outer lateral surface of the actuating element to the fluid outlet. The outlet channel can be a passage or channel in the pump housing.

The adjusting element, which can be moved back and forth in a translatory manner in relation to the pump housing, can be moved back and forth in a translatory manner, in particular, between a first position and a second position. The rotary pump preferably has a maximum delivery volume in the first position. In the second position, the rotary pump preferably has a minimum delivery volume. The actuating element can be in one piece. Preferably it is molded in one piece.

On the inlet side, that is to say for example facing the low-pressure inlet, in particular the inlet channel, the actuating element comprises a first peripheral section and a second peripheral section. Both circumferential sections extend circumferentially in the direction of rotation of the conveyor rotor, with the second circumferential section adjoining, preferably directly adjoining, the first circumferential section in the direction of rotation of the conveyor rotor. The first peripheral portion has an axial width that is less than the axial width of the conveyor. According to the invention, the second peripheral section has an axial width that is greater than the axial width of the first peripheral section. The axial width of the second peripheral section can nevertheless be smaller than the axial width of the conveying means. However, the axial width of the second peripheral section preferably corresponds at least essentially to the axial width of the conveying means. The term "substantially" is to be understood at this point as a permissible deviation that does not go beyond the manufacturing tolerances, in particular less than 0.5 mm.

The first peripheral section and the second peripheral section can at least partially radially delimit the conveying area, in particular the low-pressure area, in every position of the actuating element. In an exemplary embodiment, the first circumferential section is arranged at least partially radially between the delivery rotor and the inlet channel of the low-pressure inlet in every position of the actuating element. Alternatively or additionally, the second circumferential section is arranged at least partially radially between the delivery rotor and the inlet channel of the low-pressure inlet in every position of the actuating element. In a particularly advantageous embodiment, both the first circumferential section and the second circumferential section are arranged at least partially, preferably completely over the respective circumferential extent, radially between the delivery rotor and the inlet channel of the low-pressure inlet in every position of the actuating element.

The term "any position of the actuator" includes the first position, the second position, and any other position that the actuator can assume between the first and second positions.

In advantageous embodiments, the delivery area, in particular the low-pressure area of the delivery area, is directly fluidly connected to the low-pressure inlet, in particular the inlet channel, via the first peripheral section in the radial direction. This fluid-communicating connection between the delivery area, in particular the low-pressure area, and the low-pressure inlet, in particular the inlet channel, is preferably provided in every position of the actuating element. Alternatively or additionally, direct fluid communication between the delivery area, in particular its low-pressure area, and the low-pressure inlet, in particular the inlet channel, is prevented in the radial direction by the second peripheral section. The prevention of fluid communication between the delivery area, in particular the low-pressure area of the delivery area, and the low-pressure inlet, in particular the inlet channel, through the second peripheral section is advantageously given in every position of the actuating element. Such an embodiment has the advantage that the fluid which has already been supplied to the delivery area, in particular its low-pressure area, via the first peripheral section cannot be pushed out again radially outwards from the delivery area via the second peripheral section due to the centrifugal force.

The first peripheral section can be provided at the beginning of the low-pressure region in the direction of rotation of the feed rotor. The first circumferential section preferably extends over less than 70% of the circumferential extent of the low-pressure region in every position of the actuating element. The first circumferential section particularly preferably extends over less than 60% of the circumferential extent of the low-pressure region in every position of the actuating element. The extent of the first peripheral section, measured in the circumferential direction, can be greater than the maximum circumferential extent of two adjacent conveyor cells. In other words, the extension of the first peripheral section measured in the peripheral direction is preferably greater than the maximum peripheral distance between the two outermost conveying means of a total of three adjacent conveying means. Irrespective of this, the extent of the first peripheral section, measured in the circumferential direction, can be smaller than the maximum circumferential extent of three adjacent conveyor cells. The extent of the first circumferential portion measured in the circumferential direction is advantageously less than the maximum circumferential distance between the two outermost conveyors of a total of four adjacent conveyors.

The second peripheral section can extend in the direction of rotation of the delivery rotor up to the end of the low-pressure area, in principle also beyond the low-pressure area, as long as the delivery cells do not enlarge again. The second circumferential section preferably extends over more than 30% of the circumferential extent of the low-pressure region in every position of the actuating element. The second circumferential section particularly preferably extends over more than 40% of the circumferential extent of the low-pressure region in every position of the actuating element. The circumferential extent of the second circumferential portion may be greater than the maximum circumferential extent of a delivery cell. In other words, the extension of the second peripheral section measured in the peripheral direction is preferably greater than the maximum peripheral distance between two adjacent conveying means. Irrespective of this, the extent of the second peripheral section measured in the circumferential direction can be smaller than the maximum circumferential extent of two adjacent conveyor cells. The extension of the second peripheral section measured in the peripheral direction is preferably smaller than the maximum peripheral distance between the two outermost conveying means of a total of three adjacent conveying means.

A transition from the first circumferential section to the second circumferential section is arranged in every position of the actuating element in the low-pressure inlet. The transition can be, for example, a shoulder of the actuating element that is parallel to the axis of rotation of the conveyor rotor. In such an embodiment, the transition has almost no extension in the circumferential direction. Alternatively, the transition can also be designed as a ramp. In other words, the transition from the first peripheral section to the second peripheral section can take place in the direction of rotation of the conveyor rotor by increasing the axial width of the adjusting ring. In such an embodiment, the transition extends in the circumferential direction. The transition can be linear, concave and/or convex. A circumferentially short, preferably stepped transition is preferred.

For translational adjustment of the actuating element, the actuating element can have a number of sliding surfaces. Each sliding surface of the adjusting element preferably rests against a corresponding sliding surface of the pump housing. If the actuating element is adjusted, the sliding surfaces of the actuating element can contact the corresponding sliding surfaces of the Pump housing slide along to allow translational movements of the actuator with respect to the pump housing and to lead advantageously.

In an exemplary development, at least two sliding surfaces of the actuating element are designed as sealing sliding surfaces. Each of the sealing sliding surfaces may include at least one sealing edge facing the low pressure inlet. Advantageously, the respective sealing edges seal the low-pressure inlet in sliding contact between the pump housing and the actuating element. For example, the actuating element can have a first sealing sliding surface, which is provided in the circumferential direction, in particular counter to the direction of rotation of the conveyor rotor, next to the first circumferential section. In addition, the actuating element can have a second sealing sliding surface, which is provided in the circumferential direction, in particular in the direction of rotation of the conveyor rotor, next to the second circumferential section. Regardless of this, the first sealing sliding surface advantageously has a first sealing edge. The second sealing sliding surface can have a second sealing edge.

The first seal face can define a first imaginary plane. For example, the first imaginary plane can be spanned by the first sealing edge of the first sealing sliding surface and a further edge of the first sealing sliding surface that is orthogonal to the first sealing edge. The second seal face can define a second imaginary plane. For example, the second imaginary plane can be spanned by the second sealing edge of the second sealing sliding surface and a further edge of the second sealing sliding surface that is orthogonal to the second sealing edge. Advantageously, the first imaginary plane is aligned parallel to the second imaginary plane. The first imaginary plane can be offset parallel to or aligned congruently with the second imaginary plane.

In an exemplary embodiment, the first imaginary plane extends in every position of the adjusting element between the axis of rotation of the feed rotor and the transition of the adjusting element. Preferably, the transition from the first imaginary plane is neither intersected nor tangent. Regardless of this, the second imaginary plane can extend in any position of the actuating element between the axis of rotation of the conveyor rotor and the transition. Preferably, the transition is neither intersected nor touched by the second imaginary plane. In an exemplary development, both imaginary planes extend between the axis of rotation of the conveyor rotor and the transition. Advantageously, the transition is not intersected or tangent to either the first imaginary plane or the second imaginary plane.

The transition can be at a distance from the first sealing edge, measured in the circumferential direction, in particular counter to the direction of rotation of the conveyor rotor. This distance can be greater than or equal to a distance from the second sealing edge measured in the circumferential direction, in particular in the direction of rotation of the conveyor rotor. The distance from the transition to the first sealing edge measured in the circumferential direction, in particular counter to the direction of rotation of the feed rotor, is preferably greater than the distance from the transition to the second sealing edge measured in the circumferential direction, in particular in the direction of rotation of the feed rotor.

The distance between the transition and the first sealing edge, measured in the circumferential direction, in particular counter to the direction of rotation of the conveying rotor, can be greater than the maximum circumferential extension of two adjacent conveying cells. In other words, the distance between the transition and the first sealing edge measured in the circumferential direction, in particular counter to the direction of rotation of the conveyor rotor, is preferably greater than the maximum circumferential distance between the two outermost conveyors of a total of three adjacent conveyors. Irrespective of this, the distance between the transition and the first sealing edge, measured in the circumferential direction, in particular counter to the direction of rotation of the conveying rotor, can be smaller than the maximum circumferential extension of three adjacent conveying cells. The distance between the transition and the first sealing edge, measured in the circumferential direction, in particular counter to the direction of rotation of the conveyor rotor, is preferably smaller than the maximum circumferential distance between the two outermost conveyors of a total of four adjacent conveyors.

The distance between the transition and the second sealing edge, measured in the circumferential direction, in particular in the direction of rotation of the conveying rotor, can be greater than the maximum circumferential extension of a conveying cell. In other words, the distance between the transition and the second sealing edge, measured in the circumferential direction, in particular in the direction of rotation of the conveyor rotor, is preferably greater than the maximum circumferential distance between two adjacent conveyors. Irrespective of this, the distance between the transition and the second sealing edge, measured in the circumferential direction, in particular in the direction of rotation of the conveying rotor, can be smaller than the maximum circumferential extent of two adjacent conveying cells. The distance between the transition and the second sealing edge, measured in the circumferential direction, in particular in the direction of rotation of the conveying rotor, is preferably smaller than the maximum circumferential distance between the two outermost conveying means of a total of three adjacent conveying means.

The first peripheral portion may have an axial indentation. The indentation preferably extends over the entire radial width of the first peripheral section. The circumferential extent of the first circumferential portion may be defined by the circumferential extent of the indentation. The indentation preferably comprises an indentation base which is delimited by two indentation walls in the circumferential direction. One of the depression walls can be formed by the transition.

In an exemplary development, the second peripheral section has a recess. The recess is preferably open radially inwards, towards the conveying rotor. The recess is preferably not continuous in the radial and/or axial direction. In other words, the recess does not extend over the entire axial and/or radial width of the second peripheral section. The recess can extend in the circumferential direction, in particular counter to the direction of rotation of the conveyor rotor, up to the first circumferential section. In the opposite circumferential direction, in particular in the direction of rotation of the conveyor rotor, the recess is advantageously delimited by a wall of the actuating element. The extent of the recess starting from the first circumferential section and measured in the circumferential direction, in particular in the direction of rotation of the conveyor rotor, can be less than or equal to a maximum circumferential distance between two adjacent conveyors, but is preferably greater than a maximum circumferential distance between two adjacent conveyors.

During operation of the rotary pump, the fluid to be pumped can flow into the recess, for example from the low-pressure inlet via the first peripheral section. The recess can be designed in such a way that the fluid located in the recess has a flow direction that is tangential with respect to the conveying rotor. Advantageously, the conveying means rotating past the recess indirectly accelerate the fluid located in the recess in the direction of rotation of the conveying rotor. The fluid accelerated in the circumferential direction in the recess can then be introduced via the delimiting wall into the conveying area, in particular into the low-pressure area. Advantageously, an indirect fluid communication between the low-pressure inlet, in particular the inlet channel, and the conveying area, in particular the low-pressure area, is brought about via the recess of the second peripheral section.

The recess is delimited radially by an outer wall of the second peripheral section, so that fluid flowing tangentially into the recess is accelerated along the outer wall in the circumferential direction, but not into the low-pressure inlet can be pushed back. In the area of the outer wall, the actuating element can have an axial width which corresponds to the axial width of the conveying means, as is preferred. In principle, however, the outer wall can also have an axial width that is smaller than the axial width of the conveying means. However, the axial width of the outer wall is greater than the axial width of the first peripheral section of the actuating element. The adjusting element can have a recess over the length of the second circumferential section measured in the circumferential direction from radially outside inwards, so that the adjusting element drops in steps from the axial width of the outer wall to the smaller axial width of the recess. Although such a profile is preferred, in principle the actuating element in the second circumferential section can instead fall off in a ramp-shaped manner from radially outside inward, obliquely or with a convex or concave round curvature.

In advantageous embodiments, the rotary pump can have a flow guide structure in order to influence the fluid flowing in the low-pressure inlet, in particular to influence it in a direction-changing manner. The flow guide structure preferably protrudes axially from the pump housing into the low-pressure inlet. In particular, it can be a structure of the pump housing. Contrary to the direction of flow of the fluid in the low-pressure inlet, the flow guide structure can be wedge-shaped or tapered. Advantageously, the flow guide structure directs a first partial flow of the fluid flow in the low-pressure inlet in such a way that the first partial flow has a main flow direction when passing the actuating element, which is directed opposite to the direction of rotation of the delivery rotor. Alternatively or additionally, the flow guide structure can be shaped in such a way that a second partial flow of the fluid flow in the low-pressure inlet has a main flow direction when passing the actuating element, which corresponds to the direction of rotation of the feed rotor. Irrespective of this, the flow guide structure can be shaped in such a way that the first partial flow of the fluid flow in the low-pressure inlet is directed in the direction of the first peripheral section. Alternatively or additionally, the flow guide structure can be shaped in such a way that the second partial flow of the fluid flow in the low-pressure inlet is directed in the direction of the second peripheral section. The flow directing structure, if present, thus divides the low-pressure inlet into a first partial inlet channel, which directs the fluid to the first peripheral portion of the actuator, and a second partial inlet channel, which directs the fluid to the second peripheral portion of the actuator.

As already explained, the transition from the first circumferential section to the second circumferential section is arranged in the low-pressure inlet in every position of the actuating element. If the rotary pump has the flow guide structure, the transition can advantageously be in each Be arranged position of the actuating element in an axial plan view of the flow guide structure next to the flow guide structure in the region of the second partial inlet channel.

The actuating element forms an axial sealing gap with axially facing end faces of the pump housing on both end faces of the actuating element, which seals the conveying area radially outwards over the circumference of the actuating element within the scope of the mobility of the actuating element.

The pump housing can have one or more axial depressions in the area of the low-pressure inlet. The respective housing recess widens the low-pressure inlet axially. The respective housing recess can extend on the facing end face of the actuating element below the actuating element into the low-pressure area of the delivery area into an inlet kidney that is optionally present there, which as an axial housing recess can extend axially next to and in this sense below the delivery elements in the circumferential direction. In such designs, the fluid flows in the respective housing depression past the actuating element into the inlet kidney. The intake kidney, if present, may extend circumferentially along the first circumferential portion of the actuator and/or along the second circumferential portion of the actuator.

If the inlet kidney extends along the first peripheral section and if a housing depression of the low-pressure inlet extends into the inlet kidney on an end face of the actuating element below the first peripheral section, fluid in the housing depression can flow past the first peripheral section into the inlet kidney and from there axially into the delivery area.

If the inlet kidney extends along the second circumferential section and if a housing depression of the low-pressure inlet extends into the inlet kidney on an end face of the actuating element below the second circumferential section, fluid can flow past the second circumferential section into the inlet kidney and from there axially into the delivery area. If the axial width of the second circumferential section of the adjusting element corresponds to the width of the conveying means in such embodiments, the adjusting element in its second circumferential section does indeed prevent a radial inflow into the conveying area. However, in such embodiments, fluid can flow in from the side and thus axially into the conveying region via the part of the inlet kidney extending along the second circumferential section. If the axial width of the second peripheral section of the adjusting element is smaller than the width of the conveying means, but larger than the axial width of the first peripheral section, there will be a radial inflow via the second peripheral section compared to the first Circumferential section throttled at least. Flowing back due to centrifugal force is at least counteracted in the second peripheral section due to the axial width, which is greater according to the invention compared to the first peripheral section.

The rotary pump can be provided in particular for use in a motor vehicle. Accordingly, the rotary pump can be designed as a motor vehicle pump. The rotary pump is preferably provided for conveying a liquid, in particular a lubricant, coolant and/or actuating medium. Accordingly, the rotary pump can be designed as a liquid pump. The rotary pump is preferably provided to supply and/or lubricate and/or cool a drive motor and/or a transmission of a motor vehicle. Preferably, the liquid is an oil, such as engine lubricating oil or gear oil. The rotary pump can be designed in particular as an engine lubricant pump for a motor vehicle and/or as a transmission pump for a motor vehicle.

Figur 1

eine Schnittdarstellung eines Ausführungsbeispiels der erfindungsgemäßen Rotationspumpe;

Figur 2

eine perspektivische Darstellung der in Figur 1 gezeigten Schnittdarstellung;

Figur 3

eine perspektivische Darstellung eines Stellelements des in Figur 1 gezeigten Ausführungsbeispiels;

Figur 4

eine Draufsicht des in Figur 3 gezeigten Stellelements;

Figur 5

eine erste Schnittdarstellung des in Figur 3 gezeigten Stellelements;

Figur 6

eine zweite Schnittdarstellung des in Figur 3 gezeigten Stellelements; und

Figur 7

einen Ausschnitt einer Seitenansicht des in Figur 1 gezeigten Ausführungsbeispiels.

The features described above can be combined with one another as desired, insofar as this is technically sensible and suitable. Further features, combinations of features and advantages of the invention result from the following description of exemplary embodiments with reference to the figures. Show it:

figure 1

a sectional view of an embodiment of the rotary pump according to the invention;

figure 2

a perspective view of the figure 1 sectional view shown;

figure 3

a perspective view of an actuating element of the in figure 1 shown embodiment;

figure 4

a top view of the in figure 3 shown actuator;

figure 5

a first sectional view of the in figure 3 shown actuator;

figure 6

a second sectional view of the in figure 3 shown actuator; and

figure 7

a section of a side view of the in figure 1 shown embodiment.

figure 1 is a sectional view of an embodiment of the rotary pump 1 according to the invention. The rotary pump 1 is designed as a vane pump in the embodiment. The rotary pump 1 has a pump housing 2 which includes a low-pressure inlet 3 and a high-pressure outlet 4 for the fluid to be pumped. In order to conduct the fluid to be delivered into the interior of the rotary pump 1, the low-pressure inlet 3 has a fluid connection 3a on an outer wall of the pump housing 2 on. The fluid connection 3a forms an inlet opening for an inlet channel 3b of the low-pressure inlet 3. The inlet channel 3b extends from the fluid connection 3a into the pump housing 2. Analogously, the high-pressure outlet 4 has an outlet channel 4a in order to conduct the fluid out of the rotary pump via a fluid connection of the high-pressure outlet 4 that is not shown.

A delivery rotor 5 , which can be rotated about an axis of rotation D, is arranged inside the pump housing 2 . The delivery rotor 5 is limited axially by the pump housing 2 . A plurality of funding means 6 are distributed over the circumference of the conveying rotor 5 . In the exemplary embodiment shown, the conveying means 6 can be moved back and forth radially outwards and inwards with respect to the axis of rotation D. The conveying means 6 are arranged at equal distances from one another in the circumferential direction. Alternatively or additionally, the conveying means 6 can be arranged at different distances from one another in the circumferential direction, at least in sections. The movement of the conveying means 6 is limited radially inwards by the conveying rotor 5 . The outward movement of the conveying means 6 away from the axis of rotation D is limited by an inner lateral surface 16 of an actuating element 10 .

During operation of the rotary pump 1, the delivery rotor 5 rotates about the axis of rotation D. The delivery means 6 are pressed radially outwards in the direction of the inner lateral surface 16 of the actuating element 10 due to the centrifugal force acting on the delivery means 6. Together with the outer lateral surface 5a of the conveying rotor 5 and the inner lateral surface 16 of the actuating element 10, the axial outer edges of the conveying means 6 define a conveying area. The conveying area is thus an annular volume whose axial width corresponds to the width of the conveying means 6 . Within the conveying area, two adjacent conveying means 6 each form a conveying cell 6a. The conveying region or the conveying cells 6a are supplied with the fluid to be conveyed via the low-pressure inlet 3, in particular via the fluid connection 3a and the inlet channel 3b. In the delivery area, 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 in the delivery cells 6a under the direct influence of the rotating delivery means 6 from the low-pressure inlet 3 through the delivery area to the high-pressure outlet 4 .

The actuator 10, the detailed structure below and based on the Figures 3-6 is described in more detail is designed to change or adjust the delivery volume of the rotary pump 1 . For this purpose, the actuating element 10 can be moved back and forth between at least two positions in relation to the pump housing 2 . In the Exemplary embodiment, the actuating element 10 can be moved in a translatory manner. This means that the actuating element 10 is arranged in the pump housing 2 in a displaceable manner. The inner lateral surface 16 of the actuating element 10 extends around a central axis, not shown, which is offset parallel in a first position of the actuating element 10 in relation to the axis of rotation D of the conveyor rotor 5 . Due to the parallel offset of the central axis of the adjusting element 10 in relation to the axis of rotation D of the delivery rotor 5 , the adjusting element 10 has an eccentricity in relation to the delivery rotor 5 . figure 1 shows the actuating element 10 in the first position.

In the first position, the delivery area includes a low-pressure area in which the volume of the delivery cells 6a increases in the direction of rotation of the delivery rotor 5 . Furthermore, the delivery area in the first position of the actuating element 10 comprises a high-pressure area which adjoins the low-pressure area in the direction of rotation of the delivery rotor 5 . In the high-pressure range, the volume of the delivery cells 6a decreases in the direction of rotation of the delivery rotor 5. The rotary pump 1 has a maximum delivery volume in the first position.

In a second position, not shown, the control element 10 is displaced in the pump housing 2 in such a way that the control element 10 has minimal eccentricity or no eccentricity in relation to the delivery rotor 5 . In other words, the central axis of the actuating element 10 in the second position is essentially or almost coaxial with the axis of rotation D of the delivery rotor 5. The rotary pump 1 has a minimum delivery volume in the second position.

The first and the second position are preferably end positions of the actuating element 10. This means that the actuating element 10 cannot assume a position in which the actuating element 10 has a greater eccentricity in relation to the conveyor rotor 5 than in the first position, and/or that the actuating element 10 in relation to the conveying rotor 5 cannot have a lesser eccentricity than in the second position. Between the first position and the second position, the actuating element 10 can assume a number of, for example any number of, intermediate positions.

The rotary pump 1 comprises a restoring means 7 in order to press the actuating element 10 into the first position. The restoring means 7 preferably exerts a restoring force on the actuating element 10, with the restoring force pressing the actuating element 10 into the first position. In the exemplary embodiment shown, the restoring means 7 has two restoring springs 7, which are located on the one hand on the pump housing 2 and on the other hand on a respective pressure surface 21 of the actuating element 10 support. In order to move the actuating 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 actuating element 10. A pressurized fluid can enter the pressure chamber via the pressure channel 23 24 to be directed. The fluid pressure thus prevailing in the pressure chamber 24 presses the actuating element 10 against the restoring force of the restoring means 7 in the direction of the second position. The pressurized fluid can be, for example, the pumped fluid that is removed at a point in the high-pressure area that is still inside the pump housing 2 or at a point downstream of the high-pressure outlet 4 .

On the inlet side, i.e. in the area of the low-pressure inlet 3, the actuating element 10 comprises a first peripheral section 11 and a second peripheral section 13. Regardless of this, the delivery area is delimited or encased radially on the outside at least in sections by the first peripheral section 11 and the second peripheral section 13. The second peripheral section 13 follows the first peripheral section 11 in the direction of rotation of the conveyor rotor 5 . Both peripheral sections 11, 13 extend radially between the inner lateral surface 16 and an outer lateral surface 17 of the actuating element 10.

The first peripheral portion 11 has an axial width B ₁ which is smaller than the axial width of the conveying means 6. The second peripheral portion 13 has an axial width B ₂ which is larger than the axial width B ₁ of the first peripheral portion 11 (cf Figures 3 and 5 ). The axial width B ₂ of the second peripheral section 13 preferably corresponds to the axial width of the conveying means 6.

An extension of the first circumferential section 11 measured in the circumferential direction is greater than or equal to the circumferential extension of the second circumferential section 13. In FIG figure 1 illustrated embodiment, the extension of the first circumferential section 11 measured in the circumferential direction is greater than the circumferential extension of the second circumferential section 13.

As in figure 1 shown, the extent of the first peripheral portion 11 measured in the circumferential direction is greater than the maximum circumferential extent of two adjacent conveyor cells 6a. In other words, the extent of the first peripheral section 11 measured in the peripheral direction is greater than the maximum peripheral distance between the two outermost conveying means 6 of a total of three adjacent ones Conveying means 6. Irrespective of this, the extent of the first peripheral section 11 measured in the circumferential direction is smaller than the maximum circumferential extent of three adjacent conveying cells 6a. The extent of the first peripheral section 11 measured in the circumferential direction is smaller than the maximum circumferential distance between the two outermost conveying means 6 of a total of four adjacent conveying means 6.

The extent of the second peripheral section 13 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 section 13 measured in the circumferential direction is greater than the maximum circumferential distance between two adjacent conveying means 6. Regardless of this, the extent of the second circumferential section 13 measured in the circumferential direction is smaller than the maximum circumferential extent of two adjacent conveying cells 6a. The extent of the second peripheral section 13 measured in the circumferential direction is smaller than the maximum circumferential distance between the two outermost conveyors 6 of a total of three adjacent conveyors 6.

During operation of the rotary pump 1 , the fluid to be pumped can flow around the first peripheral section 11 in the radial direction in order to flow radially into the pumping area of the rotary pump 1 . The delivery area of the rotary pump 1 is directly fluidly connected to the low-pressure inlet 3 , in particular to the inlet channel 3a of the low-pressure inlet 3 , via the first circumferential section 11 in the radial direction. The first peripheral section 11 advantageously has the effect that the delivery cells 6a are optimally flooded with the fluid to be delivered at the beginning of the low-pressure area, in particular in a first section of the low-pressure area.

The first peripheral section 11 is formed by a depression 12 in the actuating element 10, in particular an axial depression 12. The depression 12 is continuous in the radial direction.

In the direction of rotation of the conveyor rotor 5, the first peripheral section 11 extends to a transition 15. The transition 15 is a shoulder 15 in the exemplary embodiment, and can in particular be a shoulder 15 parallel to the axis of rotation D of the conveyor rotor 5. The transition 15 connects the first peripheral portion 11 to the second peripheral portion 13. In other words, the transition 15 defines the boundary between the first peripheral portion 11 and the second peripheral portion 13. In the illustrated embodiment, the transition 15 is in every position of the actuating element 10 in the low-pressure inlet 3 arranged. The transition 15 is in every position of the actuating element 10 arranged within the extent of the low-pressure inlet 3 measured in the circumferential direction and can preferably be flown against by the fluid flowing in the low-pressure inlet 3 in any position of the actuating element 10 . In every position of the actuating element 10, the transition 15 is arranged radially between the delivery rotor 5 and a section of the low-pressure inlet 3, in particular the inlet channel 3b.

The fluid to be pumped, which already flows into the pumping cells 6a at the beginning of the low-pressure range during operation of the rotary pump 1, is subjected to a centrifugal force which increases in the direction of rotation of the pumping rotor 5 because it is carried along by the pumping means 6. This centrifugal force acting on the fluid causes the fluid to be pressed radially outwards with increasing force in the direction of rotation of the feed rotor 5 . Further flooding of the conveyor cells 6a from a radial direction is made increasingly difficult in the direction of rotation of the conveyor rotor 5 . On the contrary, the fluid even tends to be pressed out of the delivery cells 6a again. This effect occurs in particular towards the end of the low-pressure region, ie in particular in a second circumferential section 13 of the low-pressure region or of the actuating element 10 adjoining the first circumferential section 11 in the direction of rotation of the delivery rotor 5 .

The second peripheral section 13 is shaped in such a way that a radial outflow of the fluid from the delivery cells 6a is made more difficult or advantageously prevented. In other words, the second peripheral section 13 impedes or prevents direct fluid communication between the conveying region and the low-pressure inlet 3, in particular the inlet channel 3b of the low-pressure inlet 3, in the radial direction. In advantageous embodiments, the axial width B ₂ of the second peripheral section 13 corresponds at least essentially to the axial width of the conveying means 6.

In the exemplary embodiment, the second peripheral section 13 includes a recess 14. The recess 14 is an axial depression in the second peripheral section 13. The recess 14 is open radially inwards, i.e. towards the inner lateral surface 16 of the actuating element 10, and is open radially outwards through an outer wall of the actuating element 10 limited. The actuating element 10 falls axially in steps from the limiting outer wall to a bottom of the recess 14, so that the strip-shaped recess 14 around the conveying means 6 running past on the inside is obtained over the length of the second circumferential section 13 measured in the circumferential direction.

In the circumferential direction, the recess 14 extends counter to the direction of rotation of the feed rotor 5 up to the first circumferential section 11. In the direction of rotation of the feed rotor 5, the recess 14 is delimited by a wall 14a.

The fluid to be delivered can flow from the low-pressure inlet 3 into the recess 14 via the first peripheral section 11 . The fluid located in the recess 14 mainly has a tangential direction of flow with respect to the delivery rotor 5 . The conveying means 6 rotating past the recess 14 accelerate the fluid located in the recess 14 in the direction of rotation of the conveying rotor 5. However, an outer wall of the actuating element 10 delimiting the recess 14 radially on the outside holds the fluid back. The fluid accelerated in the recess 14 is then directed in the region of the wall 14a into the delivery region, in particular into the low-pressure region, of the rotary pump 1. The recess 14 enables indirect fluid communication between the delivery area and the low-pressure inlet 3 via the second peripheral section 13. The filling of the delivery cells 6a in the second peripheral section 13 is improved by the recess 14 delimited radially on the outside by the outer wall of the actuating element 10.

The rotary pump 1 includes a flow guide structure 22 which is arranged in the low-pressure inlet 3 . The flow guide structure 22 protrudes axially from a wall of the pump housing 2 into the low-pressure inlet 3 with respect to the axis of rotation D of the delivery rotor 5 . The flow guide structure 22 is preferably designed to influence the fluid flow flowing in the low-pressure inlet 3, in particular the fluid flowing in the inlet channel 3b. In the exemplary embodiment, the flow of fluid is influenced by the flow guide structure 22 at least partially in a direction-changing manner. A first partial flow of the fluid is influenced or deflected by the flow guide structure 22 in a direction-changing manner such that the first partial flow receives at least one flow direction component that is opposite to the direction of rotation of the conveyor rotor 5 . A second partial flow of the fluid is influenced or deflected by the flow guide structure 22 in a direction-changing manner such that the second partial flow receives at least one flow component that corresponds to the direction of rotation of the conveyor rotor 5 .

The flow guide structure 22 together with the pump housing 2 forms a first partial inlet channel 3c which is open on one side axially. When the rotary pump 1 is in operation, the first partial flow of the fluid flow preferably flows through the first partial inlet channel 3c. In the direction of rotation of the conveyor rotor 5, a second partial inlet channel 3d is arranged next to the first partial inlet channel 3c. The second partial inlet channel 3d is open on one side axially and is formed by the flow guide structure 22 and the pump housing 2 . Preferably the second partial flow of the fluid flows during operation of the rotary pump 1 through the second partial inlet channel 3d. In other words, the flow guide structure 22 projects axially into the low-pressure inlet 3 in such a way that it is arranged between the first partial inlet channel 3c and the second partial inlet channel 3d. The flow guide structure 22 separates the first partial inlet duct 3c from the second partial inlet duct 3d in the circumferential direction.

The flow guide structure 22 protrudes axially from only one side of the pump housing 2 into the low-pressure inlet 3, ie it does not extend over the full axial width of the low-pressure inlet 3. Fluid can therefore also flow over the flow guide structure 22. In principle, however, the flow guide structure 22 could also extend axially almost completely through the low-pressure inlet 3 .

The first peripheral section 11 is arranged axially next to and/or in the first partial inlet duct 3c in every position of the actuating element 10 . The second peripheral section 13 is arranged axially next to and/or in the second partial inlet duct 3d in every position of the actuating element 10 . In every position of the actuating element 10, the transition 15 is arranged axially next to the flow guide structure 22 and/or axially next to the second partial inlet channel 3d. Alternatively or additionally, the transition 15 can be arranged radially next to the flow guide structure 22 and/or in the second partial inlet channel 3d in any position of the actuating element 10 .

For the translational adjustment of the actuating element 10, the actuating element 10 comprises a plurality of sealing sliding surfaces 18, 19. The sealing sliding surfaces 18, 19 each lie against a sliding surface 8, 9 of the pump housing 2. If the adjusting element 10 is adjusted, the sealing sliding surfaces 18, 19 slide along the respective sliding surface 8, 9. The sealing sliding surfaces 18, 19 include sealing edges 18a, 19a, which face the low-pressure inlet 3. The sealing edges 18a, 19a seal the low-pressure inlet 3 at the transition from the pump housing 2 to the actuating element 10.

in the in figure 1 illustrated embodiment, the actuating element 10 comprises a first sealing sliding surface 18 with a first sealing edge 18a ( 3 ). The first sealing sliding surface 18 rests against a first sliding surface 8 of the pump housing 2 . A second sealing sliding surface 19 of the actuating element 10 has a second sealing edge 19a. The second sealing sliding surface 19 rests against a second sliding surface 9 of the pump housing 2 . The first sealing sliding surface 18 is arranged circumferentially opposite to the direction of rotation of the conveyor rotor 5 next to the first circumferential section 11 . The second sealing sliding surface 19 is arranged circumferentially next to the second circumferential section 13 in the direction of rotation of the conveying rotor 5 .

The transition 15 is at a distance from the first sealing edge 18a, measured in the circumferential direction, which is greater than or equal to a distance from the second sealing edge 19a, measured in the circumferential direction. in the in figure 1 illustrated embodiment, the distance of the transition 15 to the first sealing edge 18a, measured in the circumferential direction, is greater than the distance of the transition 15 to the second sealing edge 19a, measured in the circumferential direction.

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

The distance, measured in the circumferential direction, between the transition 15 and the second sealing edge 19a is greater than the maximum circumferential extent of a delivery cell 6a. In other words, the distance measured in the circumferential direction between the transition 15 and the second sealing edge 19a is greater than the maximum circumferential distance between two adjacent conveying means 6. Regardless of this, the distance measured in the circumferential direction between the transition 15 and the second sealing edge 19a is smaller than the maximum circumferential extension of two adjacent conveyor cells 6a. The distance measured in the circumferential direction between the transition 15 and the second sealing edge 19a is smaller than the maximum circumferential distance between the two outermost conveyors 6 of a total of three adjacent conveyors 6.

The first sealing sliding surface 18 preferably spans a first imaginary plane (not shown). The second sealing sliding surface 19 spans a second imaginary plane, not shown. The two imaginary planes extend parallel to one another in the direction of movement of the actuating element 10 . In the exemplary embodiment, the second imaginary plane is offset in parallel with respect to the first imaginary plane. In particular, the second imaginary plane has an orthogonal distance from the axis of rotation D that is greater than the orthogonal one Distance between the first imaginary plane and the axis of rotation D. In alternative exemplary embodiments, the two planes can also be arranged congruently with one another. Both imaginary planes extend in every position of the actuating element 10 between the axis of rotation D of the conveyor rotor 5 and the transition 15.

For a better understanding, the in figure 1 shown sectional view of the rotary pump 1 in figure 2 shown in perspective. To explain the structure and function of the in figure 2 illustrated rotary pump 1 is referred to the above statements.

figure 3 shows a perspective view of the actuating element 10 of the embodiment. However, the actuating element 10 can also be used in other rotary pumps with an adjustable delivery volume. The actuating element 10 is preferably in one piece and can in particular be formed in one piece.

The actuating element 10 is delimited radially on the outside by an outer lateral surface 17 and radially on the inside by an inner lateral surface 16 . In addition, two pressure surfaces 21 are formed on the actuating element 10, on each of which a restoring means 7 of the rotary pump 1 can be supported (restoring means 7 in figure 3 not shown). In alternative embodiments, the actuating element 10 can also have only one pressure surface 21 or more than two pressure surfaces 21 .

in the in figure 3 In the perspective view shown, the first sealing sliding surface 18 and the second sealing sliding surface 19 are visible. On the opposite side of the actuating element 10, on the side of the high-pressure outlet, the actuating element 10 comprises two further sealing sliding surfaces, which are preferably designed analogously to the first sealing sliding surface 18 and the second sealing sliding surface 19.

The edge of the first sealing sliding surface 18 facing the first peripheral section 11 forms the first sealing edge 18a. The edge of the second sealing sliding surface 19 facing the second peripheral section 13 forms the second sealing edge 19a.

The first circumferential section 11 has an axial width B ₁ which is smaller than the axial width B ₂ of the second circumferential section 13. In the circumferential direction, the first circumferential section 11 is separated from the second circumferential section 13 by the transition 15.

The first peripheral section 11 is defined by at least one indentation 12 or, as shown in the exemplary embodiment shown, two axially opposite indentations 12 formed. The recess 12 includes a recess bottom 12a. The edge 12c, which connects the outer lateral surface 17 to the depression base 12a, is preferably rounded off or has a radius. A rounded edge 12c causes a less turbulent radial inflow of the fluid to be delivered from the low-pressure inlet 3 into the delivery area of the rotary pump 1. In the circumferential direction, the depression base 12a is delimited by a depression wall 12b. The depression wall 12b arranged in the direction of rotation of the conveyor rotor 5 also forms the transition 15.

The transition 15 is a shoulder 15 of the actuating element 10. The shoulder 15 extends from the first peripheral section 11, in particular from the depression base 12a, perpendicularly in the axial direction.

The second circumferential section 13 which follows in the direction of rotation of the conveyor rotor 5 has a width B ₂ which corresponds to the axial width of the conveyor means 6 . The second peripheral portion 13 includes a recess 14 on the side of the inner lateral surface 16. The recess 14 extends in the peripheral direction from the first peripheral portion 11 and/or from the transition 15 to a wall 14a.

in the in figure 3 In the exemplary embodiment of the actuating element 10 shown, a pressure recess 25 is provided in the second sealing sliding surface 19 . When the actuating element 10 is installed, the pressure recess 25 is connected to the pressure chamber 24 via a channel 26 for fluid communication.

For a better understanding, the control element is 10 in figure 4 shown in a plan view. Figure 5 and Figure 6 show the in figure 4 marked sections of the actuating element 10. With regard to the specific structure of the actuating element 10, reference is made to the above statements.

figure 7 shows a section of a side view of the rotary pump 1. In the case of FIG figure 7 shown section, the observer looks over the low-pressure inlet 3 in the direction of flow of the fluid to be pumped into the pump housing 2.

The fluid to be delivered reaches the inlet channel 3b of the low-pressure inlet 3 via the fluid connection 3a. A first part of the inflowing fluid can flow directly, preferably in the radial direction, onto the actuating element 10, in particular onto the outer lateral surface 17 of the actuating element 10. The fluid can flow into the delivery area via the first peripheral section 11, in particular radially or at least with radial directional component flow into the conveying area, and are conveyed by the conveying means 6.

The second peripheral section 13 follows the first peripheral section 11 in the direction of rotation of the conveyor rotor 5 . The second peripheral section 13 has an axial width that corresponds to the axial width of the conveying means 6 . As a result, the second peripheral section 13 advantageously prevents the fluid to be conveyed from being able to flow out radially again from the conveying region due to the increasing centrifugal force.

A second part of the inflowing fluid impinges on the flow guide structure 22. The flow guide structure 22 directs a partial flow of the second part of the fluid into the first partial inlet channel 3c. Another partial flow of the second part of the fluid is directed through the flow guide structure 22 into the second partial inlet channel 3d.

In the exemplary embodiment, the first peripheral section 11 is arranged axially next to, in particular also axially above, the first partial inlet port 3c in every position of the actuating element 10 . The second peripheral section 13 is arranged axially next to, in particular also axially above, the second partial inlet port 3d in every position of the actuating element 10 . Depending on the position of the actuating element 10, the transition 15 is arranged either axially next to, in particular axially above, the flow guide structure 22 and/or the second partial inlet duct 3d. <u>Reference marks:</u> 1 rotary pump 13 second circumferential section 2 pump housing 14 recess 3 low pressure inlet 14a wall 3a fluid connection 15 crossing 3b inlet channel 16 inner lateral surface 3c first partial inlet port 17 outer surface 3d second partial inlet channel 18 first sealing sliding surface 4 high pressure outlet 18a first sealing edge 4a exhaust port 19 second sealing sliding surface 5 conveyor rotor 19a second sealing edge 5a outer surface 20 - 6 funding 21 printing surface 6a conveyor cells 22 flow guide structure 7 return means 23 pressure channel 8th first sliding surface 24 pressure chamber 9 second sliding surface 25 print recess 10 actuator 26 channel 11 first perimeter section 12 deepening 12a deepening reason D axis of rotation 12b cavity wall b ₁ axial width 12c edge b ₂ axial width

Claims (15)

Rotary pump (1) with variable displacement, the rotary pump (1) comprising: (a) a pump housing (2) with a low-pressure inlet (3) and a high-pressure outlet (4) for a fluid to be pumped, (b) a delivery rotor (5) arranged in the pump housing (2) so as to be rotatable about an axis of rotation (D) and having a plurality of delivery means (6) distributed over the circumference of the delivery rotor (5) for delivering the fluid from the low-pressure inlet (3) to the high-pressure outlet (4) , and (c) an adjusting element (10) that can be moved back and forth in translation with respect to the pump housing (2) for adjusting the delivery volume of the rotary pump (1), wherein (d) the actuating element (10) on the inlet side (d1) a first circumferential section (11) which extends circumferentially in the direction of rotation of the conveying rotor (5) and whose axial width (B ₁ ) is smaller than the axial width of the conveying means (6), and (d2) a second peripheral section (13) which follows the first peripheral section (11) in the direction of rotation of the conveyor rotor (5) and whose axial width (B ₂ ) is greater than the axial width (B ₁ ) of the first peripheral section (11) , has, where (E) a transition (15) from the first peripheral section (11) to the second peripheral section (13) is arranged in each position of the actuating element (10) in the low-pressure inlet (3). Rotary pump (1) according to the preceding claim, wherein the first peripheral section (11) and the second peripheral section (13) are each at least partially arranged radially between the delivery rotor (5) and an inlet channel (3b) of the low-pressure inlet (3). Rotary pump (1) according to one of the preceding claims, wherein the axial width (B ₂ ) of the second peripheral section (13) is smaller than the axial width of the conveying means (6) or preferably corresponds to the axial width of the conveying means (6). Rotary pump (1) according to one of the preceding claims, in which the transition (15) is a shoulder (15) of the actuating element (10) parallel to the axis of rotation (D) of the delivery rotor (5). Rotary pump (1) according to one of the preceding claims, wherein an outer lateral surface (5a) of the delivery rotor (5), an inner lateral surface (16) of the actuating element (10) and the axial outer edges of the delivery means (6) when the rotary pump (1) is in operation form a delivery area of the rotary pump (1) and the delivery area is directly fluidly connected to the low-pressure inlet (3) via the first peripheral section (11) in the radial direction and the second peripheral section (13) provides direct fluid communication between the delivery area and the low-pressure inlet (3) in the radial direction direction prevented. Rotary pump (1) according to Claim 5, in which the delivery area has a low-pressure area into which the fluid to be delivered flows, the first peripheral section (11) being arranged in the direction of rotation of the delivery rotor (5) at the start of the low-pressure area and changing in every position of the actuating element (10) extends over less than 70% of the circumferential extent of the low pressure area, preferably less than 60% of the circumferential extent of the low pressure area. Rotary pump (1) according to one of the preceding claims, wherein the adjusting element (10) has a first sealing sliding surface (18) which is in sliding contact with the pump housing (2) and is provided next to the first peripheral section (11) and a first sealing sliding surface (18) which is connected to the pump housing (2) in second sealing sliding surface (19) located in a sliding contact and provided next to the second peripheral section (13), the first sealing sliding surface (18) and the second sealing sliding surface (19) sliding along the pump housing (2) when the adjusting element (10) is translationally adjusted . The rotary pump (1) according to claim 7, wherein the first sealing sliding surface (18) defines a first imaginary plane and the second sealing sliding surface (19) defines a second imaginary plane, the first imaginary plane being formed parallel to the second imaginary plane and both planes in each position of the actuating element (10) between the axis of rotation (D) of the conveyor rotor (5) and the transition (15) and preferably neither intersect nor touch the transition (15). Rotary pump (1) according to claim 7 or claim 8, wherein the first sealing sliding surface (18) has a first sealing edge (18a) at one end facing the second sealing sliding surface (19) and the second sealing sliding surface (19) has a sealing edge (18a) at one end facing the first sealing sliding surface (18). End includes a second sealing edge (19a), and the Sealing edges (18a, 19a) seal the low-pressure inlet (3) in sliding contact between the pump housing (2) and the actuating element (10), with the transition (15) having a distance from the sealing edges (18a, 19a), measured in the circumferential direction, which is greater than or equal to a maximum distance measured in the circumferential direction between two adjacent conveying means (6). Rotary pump (1) according to one of Claims 7 to 9, the transition (15) having a distance from the first sealing edge (18a), measured in the circumferential direction, which is greater than or equal to a distance from the second sealing edge (19a), measured in the circumferential direction. Rotary pump (1) according to one of the preceding claims, wherein the first peripheral portion (11) and the second peripheral portion (13) have a peripheral extent which corresponds to at least a maximum distance measured in the peripheral direction between two adjacent conveying means (6). Rotary pump (1) according to one of the preceding claims, wherein the first peripheral portion (11) has a peripheral extent which is smaller than a maximum distance measured in the peripheral direction between the two outermost conveying means (6) of a total of four adjacent conveying means (6). Rotary pump (1) according to one of the preceding claims, wherein the first peripheral section (11) is formed by a radially continuous, axial depression (12) in the actuating element (10). Rotary pump (1) according to claim 12, wherein the depression (12) has a depression base (12a) which is delimited in the circumferential direction by two opposing depression walls (12b), and one of the depression walls (12b) forms the transition (15). Rotary pump (1) according to one of the preceding claims, wherein the second peripheral section (13) comprises a recess (14) which is radially open towards the delivery rotor (5) and is not axially continuous, and the recess (14) extends from the first peripheral section (11) in the direction of rotation of the Conveyor rotor (5) has a circumferential extent which corresponds at most to a maximum distance measured in the circumferential direction between two adjacent conveying means (6).

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