Rotary pump comprising an adjusting device

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.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims benefit of priority to German Patent Application No. 10 2021 125 709.3, filed Oct. 4, 2021. The contents of this application are incorporated herein by reference.

FIELD OF THE INVENTION

The invention relates to a rotary pump having an adjustable delivery volume. The rotary pump comprises a pump housing having a low-pressure inlet and a high-pressure outlet. A delivery rotor which can be rotated about a rotational axis is arranged within the pump housing. The delivery rotor comprises multiple delivery means in order to deliver a fluid to be delivered from the low-pressure inlet to the high-pressure outlet. The delivery means, which are distributed over the circumference of the delivery rotor, can in particular be radially movable in relation to the rotational axis of the delivery rotor. For adjusting the delivery volume of the rotary pump, a translationally movable setting element is arranged in the pump housing. Preferably, an inner surface area of the setting element delineates the movement of the delivery means radially outwards.

BACKGROUND OF THE INVENTION

Rotary pumps having an adjustable delivery volume are known from the prior art, in which the setting element for adjusting the delivery volume is arranged in the pump housing such that it can rotate and/or pivot in relation to the rotational axis of the delivery rotor, wherein the inner surface area of the setting element delineates a delivery region of the rotary pump on the radially outer side. The setting elements of these known rotary pumps have necessarily comprise circumferential portions which are arranged in the low-pressure inlet in any position of the setting element. There is always a circumferential portion of the setting element arranged radially between the delivery rotor, in particular the delivery region, and the fluid flowing in through the low-pressure inlet. In order to nonetheless be able to ensure a radial inflow and/or supply of fluid to the delivery region, said circumferential portions regularly exhibit an axial width which is smaller than the axial width of the delivery means.

The rotary pumps known from the prior art have the disadvantage that the radial inflow decreases in the rotational direction of the delivery rotor. The is due to the fact that fluid flowing into the delivery region is carried off in the circumferential direction and accelerated, such that it is exposed to a centrifugal force which increases in the rotational direction of the delivery rotor and presses it radially outwards. This effect has a negative influence on the delivering characteristics. It can even occur that some of the fluid flows radially outwards back into the low-pressure inlet. This unwanted effect is mainly dependent on the rotational speed of the delivery rotor and occurs in all positions of the setting element and is in particular disruptive in positions of maximum delivery volume.

SUMMARY OF THE INVENTION

An aspect of the invention is a rotary pump which exhibits improved delivery characteristics and which can be manufactured cost-effectively.

The rotary pump in accordance with an aspect of the invention comprises a pump housing having a low-pressure inlet and a high-pressure outlet for a fluid to be delivered. A delivery rotor which can be rotated about a rotational axis is arranged within the pump housing. The delivery rotor comprises multiple delivery means which are distributed over the circumference of the delivery rotor and can for example be movable, radially or with a radial direction component, in relation to the rotational axis of the delivery rotor. The delivery means can be arranged on a rotor base body of the delivery rotor. For adjusting the delivery volume of the rotary pump, the rotary pump comprises a setting element which can be translationally moved back and forth 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 the constituent parts of the component experience the same shift, i.e. exhibit the same velocity vector and/or acceleration vector at a given point in time.

A “rotary movement” or “rotational movement” is understood to mean a change in the position of the corresponding component in relation to the pump housing, in which all the constituent parts of the component are moved circularly about a common axis.

Preferably, a delivery region of the rotary pump is radially delineated by an outer surface area of the rotor, in particular an outer surface area of the rotor base body, and an inner surface area of the setting element. The delivery region can be axially defined by the axial extent of the delivery means. Within the delivery region, a delivery cell can be formed by two respectively adjacent delivery means together with the outer surface area of the rotor, in particular the outer surface area of the rotor base body, and the inner surface area of the setting element. The cell volume of a delivery cell preferably changes while the rotary pump is in operation (while the delivery rotor is rotating). The delivery region can comprise a low-pressure region and a high-pressure region. The low-pressure region is for example defined by the cell volume of the delivery cells increasing in the rotational direction of the delivery rotor. The high-pressure region is for example defined by the cell volume of the delivery cells decreasing in the rotational direction of the delivery rotor.

The low-pressure inlet preferably extends from a fluid port on the outer wall of the pump housing up to or into the delivery region, in particular up to or into the low-pressure region. The fluid to be delivered can be fed to the delivery region via the low-pressure inlet. Irrespective of this, the low-pressure inlet can comprise multiple sub-portions. An inlet channel can for example adjoin the fluid port in the flow direction of the fluid to be delivered. The inlet channel advantageously extends from the fluid port up to an outer surface area of the setting element. The inlet channel can be a passage or channel in the pump housing. From the outer surface area of the setting element, the inlet channel can transition into a feed portion. The feed portion can comprise one or more sub-channels and/or pockets and/or recesses and/or nodules in the pump housing. These preferably enable an axial supply of the fluid to the low-pressure region of the delivery region. Irrespective of this, the feed portion can also comprise cavities and/or recesses in other components of the rotary pump, such as for example the setting element, in order to enable a supply, in particular a radial supply, of fluid to the delivery region, in particular the low-pressure region.

The high-pressure outlet extends from the delivery region, in particular from the high-pressure region, up to a fluid outlet on the outer wall of the pump housing. The delivered fluid can be discharged from the delivery region, in particular from the high-pressure region, through the high-pressure outlet. Irrespective of this, the high-pressure outlet can comprise multiple sub-portions. An outlet portion can for example adjoin the delivery region, in particular the high-pressure region, in the flow direction of the fluid to be delivered. The outlet portion can be formed by one or more sub-channels, pockets, recesses and/or nodules in the pump housing. These preferably enable an axial discharge of the delivered fluid from the delivery region, in particular from the high-pressure region. Irrespective of this, the outlet portion can also comprise cavities and/or recesses in other components of the rotary pump, such as for example the setting element, in order to enable a discharge, in particular a radial discharge, of the fluid from the delivery region, in particular from the high-pressure region. From the outer surface area of the setting element, the outlet region can transition into an outlet channel. The outlet channel advantageously extends from the outer surface area of the setting element up to the fluid outlet. The outlet channel can be a passage or channel in the pump housing.

The setting element, which can be translationally moved back and forth in relation to the pump housing, can in particular be translationally moved back and forth between a first position and a second position. The rotary pump preferably exhibits a maximum delivery volume in the first position. The rotary pump preferably exhibits a minimum delivery volume in the second position. The setting element can consist of one part. It is preferably molded in one piece.

The setting element comprises a first circumferential portion and a second circumferential portion at the inlet end, i.e. for example facing the low-pressure inlet, in particular the inlet channel. Both circumferential portions extend circumferentially in the rotational direction of the delivery rotor, wherein the second circumferential portion adjoins the first circumferential portion, preferably directly, in the rotational direction of the delivery rotor. The first circumferential portion exhibits an axial width which is smaller than the axial width of the delivery means. In accordance with an aspect of the invention, the second circumferential portion exhibits an axial width which is greater than the axial width of the first circumferential portion. The axial width of the second circumferential portion can nonetheless be smaller than the axial width of the delivery means. Preferably, however, the axial width of the second circumferential portion corresponds at least substantially to the axial width of the delivery means. At this juncture, the term “substantially” shall be understood to mean a permissible deviation which does not exceed the manufacturing tolerances and which is in particular less than 0.5 mm.

The first circumferential portion and the second circumferential portion can at least partially radially delineate the delivery region, in particular the low-pressure region, in any position of the setting element. In an example embodiment, the first circumferential portion is at least partially arranged radially between the delivery rotor and the inlet channel of the low-pressure inlet in any position of the setting element. Alternatively, or additionally, the second circumferential portion is at least partially arranged radially between the delivery rotor and the inlet channel of the low-pressure inlet in any position of the setting element. In a particularly advantageous embodiment, both the first circumferential portion and the second circumferential portion are arranged at least partially, and preferably completely over their respective circumferential extent, radially between the delivery rotor and the inlet channel of the low-pressure inlet in any position of the setting element.

The descriptor “any position of the setting element” includes the first position, the second position and any other position between the first position and the second position which the setting element can assume.

In advantageous embodiments, the delivery region, in particular the low-pressure region of the delivery region, is connected in direct fluid communication with the low-pressure inlet, in particular the inlet channel, via the first circumferential portion in the radial direction. This fluid-communicating connection between the delivery region, in particular the low-pressure region, and the low-pressure inlet, in particular the inlet channel, is preferably provided in any position of the setting element. Alternatively, or additionally, direct fluid communication between the delivery region, in particular the low-pressure region of the delivery region, and the low-pressure inlet, in particular the inlet channel, is prevented by the second circumferential portion in the radial direction. Fluid communication between the delivery region, in particular the low-pressure region of the delivery region, and the low-pressure inlet, in particular the inlet channel, is advantageously prevented by the second circumferential portion in any position of the setting element. This embodiment has the advantage that the fluid which has already been fed to the delivery region, in particular the low-pressure region of the delivery region, via the first circumferential portion cannot be pressed radially outwards back out of the delivery region via the second circumferential portion by the centrifugal force.

The first circumferential portion can be provided at the beginning of the low-pressure region in the rotational direction of the delivery rotor. The first circumferential portion preferably extends over less than 70% of the circumferential extent of the low-pressure region in any position of the setting element. The first circumferential portion particularly preferably extends over less than 60% of the circumferential extent of the low-pressure region in any position of the setting element. The extent of the first circumferential portion as measured in the circumferential direction can be greater than the maximum circumferential extent of two adjacent delivery cells. In other words, the extent of the first circumferential portion as measured in the circumferential direction is preferably greater than the maximum circumferential distance between the two outermost delivery means of a total of three adjacent delivery means. Irrespective of this, the extent of the first circumferential portion as measured in the circumferential direction can be smaller than the maximum circumferential extent of three adjacent delivery cells. The extent of the first circumferential portion as measured in the circumferential direction is advantageously smaller than the maximum circumferential distance between the two outermost delivery means of a total of four adjacent delivery means.

The second circumferential portion can extend up to the end of the low-pressure region in the rotational direction of the delivery rotor, and in principle beyond the low-pressure region, as long as the delivery cells do not increase in size again. The second circumferential portion preferably extends over more than 30% of the circumferential extent of the low-pressure region in any position of the setting element. The second circumferential portion particularly preferably extends over more than 40% of the circumferential extent of the low-pressure region in any position of the setting element. The extent of the second circumferential portion as measured in the circumferential direction can be greater than the maximum circumferential extent of a delivery cell. In other words, the extent of the second circumferential portion as measured in the circumferential direction is preferably greater than the maximum circumferential distance between two adjacent delivery means. Irrespective of this, the extent of the second circumferential portion as measured in the circumferential direction can be smaller than the maximum circumferential extent of two adjacent delivery cells. The extent of the second circumferential portion as measured in the circumferential direction is preferably smaller than the maximum circumferential distance between the two outermost delivery means of a total of three adjacent delivery means.

A transition from the first circumferential portion to the second circumferential portion is arranged in the low-pressure inlet in any position of the setting element. The transition can for example be a collar of the setting element which is parallel to the rotational axis of the delivery rotor. In this embodiment, the transition exhibits almost no extent in the circumferential direction. Alternatively, the transition can also be embodied as a ramp. In other words, the transition from the first circumferential portion to the second circumferential portion can be formed by an increase in the axial width of the setting ring in the rotational direction of the delivery rotor. In this embodiment, the transition does exhibit an extent in the circumferential direction. The transition can be embodied to be linear, concave and/or convex. A transition which is short in the circumferential direction—most preferably, a stepped transition—is preferred.

For translationally adjusting the setting element, the setting element can comprise multiple sliding surfaces. Each sliding surface of the setting element preferably abuts a corresponding sliding surface of the pump housing. If the setting element is adjusted, the sliding surfaces of the setting element can slide along corresponding sliding surfaces of the pump housing in order to enable and advantageously guide translational movements of the setting element in relation to the pump housing.

In an example development, at least two sliding surfaces of the setting element are embodied as sealing sliding surfaces. Each of the sealing sliding surfaces can comprise at least one sealing edge which faces the low-pressure inlet. Advantageously, the respective sealing edges seal off the low-pressure inlet in the sliding contact between the pump housing and the setting element. The setting element can for example comprise a first sealing sliding surface which is provided next to the first circumferential portion in the circumferential direction, in particular counter to the rotational direction of the delivery rotor. The setting element can additionally comprise a second sealing sliding surface which is provided next to the second circumferential portion in the circumferential direction, in particular in the rotational direction of the delivery rotor. Irrespective of this, the first sealing sliding surface advantageously comprises a first sealing edge. The second sealing sliding surface can comprise a second sealing edge.

The first sealing sliding surface can define a first imaginary plane. The first imaginary plane can for example be spanned by the first sealing edge of the first sealing sliding surface and another edge of the first sealing sliding surface which is orthogonal to the first sealing edge. The second sealing sliding surface can define a second imaginary plane. The second imaginary plane can for example be spanned by the second sealing edge of the second sealing sliding surface and another edge of the second sealing sliding surface which is orthogonal to the second sealing edge. Advantageously, the first imaginary plane is aligned in parallel with the second imaginary plane. The first imaginary plane can be offset in parallel with respect to second imaginary plane or aligned congruently with the second imaginary plane.

In an example embodiment, the first imaginary plane extends between the rotational axis of the delivery rotor and the transition of the setting element in any position of the setting element. The transition is preferably neither intersected by nor tangent to the first imaginary plane. Irrespective of this, the second imaginary plane can extend between the rotational axis of the delivery rotor and the transition in any position of the setting element. The transition is preferably neither intersected by nor tangent to the second imaginary plane. In an example development, both imaginary planes extend between the rotational axis of the delivery rotor and the transition. The transition is advantageously neither intersected by or tangent to either the first imaginary plane or the second imaginary plane.

The transition can exhibit a distance from the first sealing edge as measured in the circumferential direction, in particular counter to the rotational direction of the delivery rotor. This distance can be greater than or equal to a distance from the second sealing edge as measured in the circumferential direction, in particular in the rotational direction of the delivery rotor. The distance between the transition and the first sealing edge as measured in the circumferential direction, in particular counter to the rotational direction of the delivery rotor, is preferably greater than the distance between the transition and the second sealing edge as measured in the circumferential direction, in particular in the rotational direction of the delivery rotor.

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

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

The first circumferential portion can comprise an axial recess. The recess preferably extends over the entire radial width of the first circumferential portion. The circumferential extent of the first circumferential portion can be defined by the circumferential extent of the recess. The recess preferably comprises a recess base which is delineated in the circumferential direction by two recess walls. One of the recess walls can be formed by the transition.

In an example development, the second circumferential portion comprises a cavity. The cavity is preferably open radially inwards, towards the delivery rotor. The cavity is preferably not continuous in the radial and/or axial direction. In other words, the cavity does not extend over the entire axial and/or radial width of the second circumferential portion. The cavity can extend in the circumferential direction, in particular counter to the rotational direction of the delivery rotor, up to the first circumferential portion. In the opposite circumferential direction, in particular in the rotational direction of the delivery rotor, the cavity is advantageously delineated by a wall of the setting element. The extent of the cavity starting from the first circumferential portion and measured in the circumferential direction, in particular in the rotational direction of the delivery rotor, can be smaller than or equal to a maximum circumferential distance between two adjacent delivery means, but is preferably greater than a maximum circumferential distance between two adjacent delivery means.

While the rotary pump is in operation, the fluid to be delivered can for example flow from the low-pressure inlet into the cavity via the first circumferential portion. The cavity can be embodied such that the fluid situated in the cavity exhibits a flow direction which is tangential in relation to the delivery rotor. Advantageously, the delivery means which rotate past the cavity indirectly accelerate the fluid situated in the cavity in the rotational direction of the delivery rotor. The fluid accelerated in the circumferential direction in the cavity can then be introduced into the delivery region, in particular into the low-pressure region, via the delineating wall. Advantageously, indirect fluid communication between the low-pressure inlet, in particular the inlet channel, and the delivery region, in particular the low-pressure region, is achieved via the cavity of the second circumferential portion.

The cavity is radially delineated by an outer wall of the second circumferential portion, such that fluid flowing tangentially into the cavity can be accelerated along the outer wall in the circumferential direction, but not pressed back into the low-pressure inlet. In the region of the outer wall, the setting element can exhibit an axial width which corresponds to the axial width of the delivery means, as is preferred. The outer wall can however also in principle exhibit an axial width which is smaller than the axial width of the delivery means. The axial width of the outer wall is however greater than the axial width of the first circumferential portion of the setting element. The setting element can comprise a depression from the radially outer side inwards over the length of the second circumferential portion as measured in the circumferential direction, such that the setting element drops incrementally from the axial width of the outer wall to the comparatively smaller axial width of the cavity. Although this profile is preferred, the setting element can however in principle instead drop from the radially outer side inwards in the shape of a ramp or obliquely or in a convexly or concavely rounded curve in the second circumferential portion.

In advantageous embodiments, the rotary pump can comprise a flow channeling structure in order to influence and in particular redirect the fluid flowing in the low-pressure inlet. The flow channeling structure preferably protrudes axially from the pump housing into the low-pressure inlet. It can in particular be a structure of the pump housing. The flow channeling structure can be embodied to taper, in the shape of a wedge or conically, counter to the flow direction of the fluid in the low-pressure inlet. Advantageously, the flow channeling structure directs a first sub-flow of the fluid flow in the low-pressure inlet in such a way that the first sub-flow exhibits a main flow direction, when passing the setting element, which is directed counter to the rotational direction of the delivery rotor. Alternatively, or additionally, the flow channeling structure can be shaped such that a second sub-flow of the fluid flow in the low-pressure inlet exhibits a main flow direction, when passing the setting element, which corresponds to the rotational direction of the delivery rotor. Irrespective of this, the flow channeling structure can be shaped such that the first sub-flow of the fluid flow in the low-pressure inlet is directed towards the first circumferential portion. Alternatively, or additionally, the flow channeling structure can be shaped such that the second sub-flow of the fluid flow in the low-pressure inlet is directed towards the second circumferential portion. The flow channeling structure, if provided, thus sub-divides the low-pressure inlet into a first inlet sub-channel, which channels the fluid to the first circumferential portion of the setting element, and a second inlet sub-channel which channels the fluid to the second circumferential portion of the setting element.

As already explained, the transition from the first circumferential portion to the second circumferential portion is arranged in the low-pressure inlet in any position of the setting element. If the rotary pump comprises the flow channeling structure, the transition can advantageously be arranged next to the flow channeling structure in the region of the second inlet sub-channel in an axial plan view onto the flow channeling structure in any position of the setting element.

The setting element forms an axial sealing gap with axially facing end faces of the pump housing on each of the two end sides of the setting element, wherein the axial sealing gap seals the delivery region radially outwards over the circumference of the setting element within the scope of the setting element's ability to move.

The pump housing can comprise one or more axial recesses in the region of the low-pressure inlet. The respective housing recess axially widens the low-pressure inlet. The respective housing recess can extend on the facing end side of the setting element below the setting element into the low-pressure region of the delivery region, into an inlet nodule which is optionally provided therein and which can extend as an axial housing recess axially next to and in this sense below the delivery elements in the circumferential direction. In such embodiments, the fluid flows in the respective housing recess, past the setting element, into the inlet nodule. The inlet nodule, if provided, can extend in the circumferential direction along the first circumferential portion of the setting element and/or along the second circumferential portion of the setting element.

If the inlet nodule extends along the first circumferential portion, and a housing recess of the low-pressure inlet extends into the inlet nodule on an end side of the setting element below the first circumferential portion, fluid in the housing recess can flow past the first circumferential portion into the inlet nodule and from there axially into the delivery region.

If the inlet nodule extends along the second circumferential portion, and a housing recess of the low-pressure inlet extends into the inlet nodule on an end side of the setting element below the second circumferential portion, fluid can flow past the second circumferential portion into the inlet nodule and from there axially into the delivery region. If the axial width of the second circumferential portion of the setting element corresponds to the width of the delivery means in such embodiments, the setting element does prevent a radial flow into the delivery region in its second circumferential portion, but fluid can flow from the side via the part of the inlet nodule extending along the second circumferential portion and thus flow axially into the delivery region in such embodiments. If the axial width of the second circumferential portion of the setting element is smaller than the width of the delivery means, but greater than the axial width of the first circumferential portion, a radial inflow via the second circumferential portion is at least throttled as compared to the first circumferential portion. The axial width which in accordance with an aspect of the invention is greater than that of the first circumferential portion at least counteracts a backflow due to centrifugal force in the second circumferential portion.

The rotary pump can in particular be designed for use in a motor vehicle. The rotary pump can accordingly be embodied as a motor vehicle pump. The rotary pump is preferably designed for delivering a liquid, in particular a lubricant, coolant and/or actuating medium. The rotary pump can accordingly be embodied as a liquid pump. The rotary pump is preferably designed for supplying and/or lubricating and/or cooling a drive motor and/or a transmission of a motor vehicle. The liquid is preferably an oil, for example an engine lubricating oil or a transmission oil. The rotary pump can in particular be embodied as an engine lubricant pump for a motor vehicle and/or as a transmission pump for a motor vehicle.

DETAILED DESCRIPTION OF THE INVENTION

FIG.1is a sectional representation of an example embodiment of the rotary pump1in accordance with the invention. In the example embodiment, the rotary pump1is embodied as a vane pump. The rotary pump1comprises a pump housing2comprising a low-pressure inlet3and a high-pressure outlet4for the fluid to be delivered. In order to channel the fluid to be delivered into the interior of the rotary pump1, the low-pressure inlet3comprises a fluid port3aon an outer wall of the pump housing2. The fluid port3aforms an inlet intersection for an inlet channel3bof the low-pressure inlet3. The inlet channel3bextends from the fluid port3ainto the pump housing2. Similarly, the high-pressure outlet4comprises an outlet channel4ain order to channel the fluid out of the rotary pump via a fluid port (not shown) of the high-pressure outlet4.

A delivery rotor5, which can be rotated about a rotational axis D, is arranged within the pump housing2. The delivery rotor5is axially delineated by the pump housing2. Multiple delivery means6are distributed over the circumference of the delivery rotor5. In the example embodiment shown, the delivery means6can be moved back and forth radially outwards and inwards in relation to the rotational axis D. The delivery means6are arranged at equal distances from each other in the circumferential direction. Alternatively, or additionally, the delivery means6can be arranged at different distances from each other in the circumferential direction, at least in portions. The movement of the delivery means6is delineated radially inwards by the delivery rotor5. The movement of the delivery means6outwards, away from the rotational axis D, is delineated by an inner surface area16of a setting element10.

While the rotary pump1is in operation, the delivery rotor5rotates about the rotational axis D, wherein the delivery means6are pressed radially outwards towards the inner surface area16of the setting element10by the centrifugal force acting on the delivery means6. The axial outer edges of the delivery means6, together with the outer surface area5aof the delivery rotor5and the inner surface area16of the setting element10, define a delivery region. The delivery region is thus an annular volume, the axial width of which corresponds to the width of the delivery means6. Within the delivery region, each two adjacent delivery means6form a delivery cell6a. The fluid to be delivered is supplied to the delivery region and/or the delivery cells6avia the low-pressure inlet3, in particular via the fluid port3aand the inlet channel3b. In the delivery region, the fluid to be delivered is delivered from the low-pressure inlet3to the high-pressure outlet4, in particular to the outlet channel4a. The fluid to be delivered is delivered from the low-pressure inlet3to the high-pressure outlet4, through the delivery region, in the delivery cells6adue to the direct influence of the rotating delivery means6.

The setting element10, the detailed structure of which is described in more detail further below and on the basis ofFIGS.3to6, is embodied to alter and/or adjust the delivery volume of the rotary pump1. For this purpose, the setting element10can be moved back and forth between at least two positions in relation to the pump housing2. In the example embodiment, the setting element10can be translationally moved, i.e. the setting element10is arranged such that it can be shifted in the pump housing2. The inner surface area16of the setting element10extends around a central axis (not shown) which is offset in parallel in relation to the rotational axis D of the delivery rotor5when the setting element10is in a first position. Because the central axis of the setting element10is offset in parallel in relation to the rotational axis D of the delivery rotor5, the setting element10exhibits an eccentricity in relation to the delivery rotor5.FIG.1shows the setting element10in its first position.

In the first position, the delivery region comprises a low-pressure region in which the volume of the delivery cells6aincreases in the rotational direction of the delivery rotor5. When the setting element10is 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 rotor5. In the high-pressure region, the volume of the delivery cells6adecreases in the rotational direction of the delivery rotor5. The rotary pump1exhibits a maximum delivery volume in the first position.

In a second position (not shown), the setting element10is shifted in the pump housing2such that the setting element10exhibits a minimum eccentricity or no eccentricity in relation to the delivery rotor5. In other words, the central axis of the setting element10is substantially or almost coaxial with the rotational axis D of the delivery rotor5in the second position. The rotary pump1exhibits a minimum delivery volume in the second position.

The first position and second position are preferably end positions of the setting element10, i.e. the setting element10cannot assume a position in which it exhibits a greater eccentricity in relation to the delivery rotor5than in the first position and/or a smaller eccentricity in relation to the delivery rotor5than in the second position. The setting element10can assume multiple intermediate positions, for example any number of intermediate positions, between the first position and the second position.

The rotary pump1comprises a restoring means7in order to press the setting element10into the first position. The restoring means7preferably exerts a restoring force on the setting element10, wherein the restoring force presses the setting element10into the first position. In the example embodiment shown, the restoring means7comprises two restoring springs7which are supported on the one hand on the pump housing2and on the other hand on a respective pressure surface21of the setting element10. In order to move the setting element10into the second position, the rotary pump1comprises a pressure channel23and a pressure chamber24. The pressure chamber24extends between the pump housing2and the setting element10. A pressurized fluid can be channeled into the pressure chamber24via the pressure channel23. The fluid pressure thus prevailing in the pressure chamber24presses the setting element10towards the second position, against the restoring force of the restoring means7. 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 housing2or a point downstream of the high-pressure outlet4.

At the inlet end, i.e. in the region of the low-pressure inlet3, the setting element10comprises a first circumferential portion11and a second circumferential portion13. Irrespective of this, the delivery region is delineated or surrounded on the radially outer side, at least in portions, by the first circumferential portion11and the second circumferential portion13. The second circumferential portion13adjoins the first circumferential portion11in the rotational direction of the delivery rotor5. Both circumferential portions11,13extend radially between the inner surface area16and an outer surface area17of the setting element10.

The first circumferential portion11exhibits an axial width B1which is smaller than the axial width of the delivery means6. InFIG.13, one of the delivery means6of width B6is shown to the left of the setting element10. The second circumferential portion13exhibits an axial width B2which is greater than the axial width B1of the first circumferential portion11(cf.FIGS.3and5). The axial width B2of the second circumferential portion13preferably corresponds to the axial width B6of the delivery means6.

An extent of the first circumferential portion11as measured in the circumferential direction is greater than or equal to the circumferential extent of the second circumferential portion13. In the example embodiment shown inFIG.1, the extent of the first circumferential portion11as measured in the circumferential direction is greater than the circumferential extent of the second circumferential portion13.

As shown inFIG.1, the extent of the first circumferential portion11as measured in the circumferential direction is greater than the maximum circumferential extent of two adjacent delivery cells6a. In other words, the extent of the first circumferential portion11as measured in the circumferential direction is greater than the maximum circumferential distance between the two outermost delivery means6of a total of three adjacent delivery means6. Irrespective of this, the extent of the first circumferential portion11as measured in the circumferential direction is smaller than the maximum circumferential extent of three adjacent delivery cells6a. The extent of the first circumferential portion11as measured in the circumferential direction is smaller than the maximum circumferential distance between the two outermost delivery means6of a total of four adjacent delivery means6.

The extent of the second circumferential portion13as measured in the circumferential direction is greater than the maximum circumferential extent of a delivery cell6a. In other words, the extent of the second circumferential portion13as measured in the circumferential direction is greater than the maximum circumferential distance between two adjacent delivery means6. Irrespective of this, the extent of the second circumferential portion13as measured in the circumferential direction is smaller than the maximum circumferential extent of two adjacent delivery cells6a. The extent of the second circumferential portion13as measured in the circumferential direction is smaller than the maximum circumferential distance between the two outermost delivery means6of a total of three adjacent delivery means6.

While the rotary pump1is in operation, the fluid to be delivered can flow around the first circumferential portion11in the radial direction in order to radially flow into the delivery region of the rotary pump1. The delivery region of the rotary pump1is connected in direct fluid communication with the low-pressure inlet3, in particular the inlet channel3aof the low-pressure inlet3, via the first circumferential portion11in the radial direction. The first circumferential portion11advantageously causes the delivery cells6ato 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.

The first circumferential portion11is formed by a recess12, in particular an axial recess12, in the setting element10. The recess12is continuous in the radial direction.

The first circumferential portion11extends in the rotational direction of the delivery rotor5up to a transition15. In the example embodiment, the transition15is a collar15and can in particular be a collar15which is parallel to the rotational axis D of the delivery rotor5. The transition15connects the first circumferential portion11to the second circumferential portion13. In other words, the transition15defines the boundary between the first circumferential portion11and the second circumferential portion13. In the example embodiment shown, the transition15is arranged in the low-pressure inlet3in any position of the setting element10. The transition15is arranged within the range of extent of the low-pressure inlet3as measured in the circumferential direction in any position of the setting element10, and the fluid flowing in the low-pressure inlet3can preferably flow onto it in any position of the setting element10. The transition15is arranged radially between the delivery rotor5and a portion of the low-pressure inlet3, in particular the inlet channel3b, in any position of the setting element10.

The fluid to be delivered, which flows into the delivery cells6aeven at the beginning of the low-pressure region while the rotary pump1is in operation, is subjected to a centrifugal force which increases in the rotational direction of the delivery rotor5because it is carried off by the delivery means6. 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 rotor5. Further flooding of the delivery cells6afrom a radial direction is increasingly impeded in the rotational direction of the delivery rotor5. Instead, the fluid even tends to be pressed back out of the delivery cells6a. This effect occurs in particular towards the end of the low-pressure region, i.e. in particular in a second circumferential portion13of the low-pressure region or setting element10which adjoins the first circumferential portion11in the rotational direction of the delivery rotor5.

The second circumferential portion13is shaped such that a radial flow of the fluid out of the delivery cells6ais impeded or advantageously prevented. In other words, the second circumferential portion13impedes or prevents direct fluid communication between the delivery region and the low-pressure inlet3, in particular the inlet channel3bof the low-pressure inlet3, in the radial direction. To this end, the axial width B2of the second circumferential portion13corresponds at least substantially to the axial width B6of the delivery means6in advantageous embodiments.

In the example embodiment, the second circumferential portion13comprises a cavity14. The cavity14is an axial recess in the second circumferential portion13. The cavity14is open radially inwards, i.e. towards the inner surface area16of the setting element10, and is delineated on the radially outer side by an outer wall of the setting element10. The setting element10axially drops incrementally from the delineating outer wall onto a base of the cavity14, such that the strip-shaped cavity14around the delivery means6which pass on the inside is obtained over the length of the second circumferential portion13as measured in the circumferential direction.

The cavity14extends in the circumferential direction, counter to the rotational direction of the delivery rotor5, up to the first circumferential portion11. The cavity14is delineated in the rotational direction of the delivery rotor5by a wall14a.

The fluid to be delivered can flow from the low-pressure inlet3into the cavity14via the first circumferential portion11. The fluid situated in the cavity14mainly exhibits a tangential flow direction in relation to the delivery rotor5. The delivery means6which rotate past the cavity14accelerate the fluid situated in the cavity14in the rotational direction of the delivery rotor5. However, an outer wall of the setting element10which delineates the cavity14on the radially outer side holds the fluid back. The fluid accelerated in the cavity14is then directed into the delivery region, in particular into the low-pressure region, of the rotary pump1in the region of the wall14a. The cavity14enables indirect fluid communication between the delivery region and the low-pressure inlet3via the second circumferential portion13. The filling of the delivery cells6ain the second circumferential portion13is improved by the cavity14which is delineated on the radially outer side by the outer wall of the setting element10.

The rotary pump1comprises a flow channeling structure22which is arranged in the low-pressure inlet3. The flow channeling structure22protrudes axially, in relation to the rotational axis D of the delivery rotor5, from a wall of the pump housing2into the low-pressure inlet3. The flow channeling structure22is preferably embodied to influence the fluid flow flowing in the low-pressure inlet3, in particular the fluid flowing in the inlet channel3b. In the example embodiment, the fluid flow is at least partially redirected by the flow channeling structure22. A first sub-flow of the fluid is redirected and/or deflected by the flow channeling structure22in 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 rotor5. A second sub-flow of the fluid is redirected and/or deflected by the flow channeling structure22in such a way that the second sub-flow obtains at least a flow component which corresponds to the rotational direction of the delivery rotor5.

The flow channeling structure22, together with the pump housing2, forms a first inlet sub-channel3cwhich is axially open on one side. The first sub-flow of the fluid flow preferably flows through the first inlet sub-channel3cwhile the rotary pump1is in operation. A second inlet sub-channel3dis arranged next to the first inlet sub-channel3cin the rotational direction of the delivery rotor5. The second inlet sub-channel3dis axially open on one side and is formed by the flow channeling structure22and the pump housing2. The second sub-flow of the fluid preferably flows through the second inlet sub-channel3dwhile the rotary pump1is in operation. In other words, the flow channeling structure22protrudes axially into the low-pressure inlet3such that it is arranged between the first inlet sub-channel3cand the second inlet sub-channel3d. The flow channeling structure22separates the first inlet sub-channel3cfrom the second inlet sub-channel3din the circumferential direction.

The flow channeling structure22protrudes axially from only one side of the pump housing2into the low-pressure inlet3, i.e. it does not extend over the full axial width of the low-pressure inlet3. Fluid can therefore also flow across the flow channeling structure22. The flow channeling structure22could however in principle also axially extend almost completely through the low-pressure inlet3.

The first circumferential portion11is arranged axially next to and/or in the first inlet sub-channel3cin any position of the setting element10. The second circumferential portion13is arranged axially next to and/or in the second inlet sub-channel3din any position of the setting element10. The transition15is arranged axially next to the flow channeling structure22and/or axially next to the second inlet sub-channel3din any position of the setting element10. Alternatively, or additionally, the transition15can be arranged radially next to the flow channeling structure22and/or in the second inlet sub-channel3din any position of the setting element10.

For translationally adjusting the setting element10, the setting element10comprises multiple sealing sliding surfaces18,19. Each sealing sliding surface18,19respectively abuts a sliding surface8,9of the pump housing2. If the setting element10is adjusted, the sealing sliding surfaces18,19slide along the respective sliding surface8,9. The sealing sliding surfaces18,19comprise sealing edges18a,19awhich face the low-pressure inlet3. The sealing edges18a,19aseal off the low-pressure inlet3at the transition from the pump housing2to the setting element10.

In the example embodiment shown inFIG.1, the setting element10comprises a first sealing sliding surface18comprising a first sealing edge18a(FIG.3). The first sealing sliding surface18abuts a first sliding surface8of the pump housing2. A second sealing sliding surface19of the setting element10comprises a second sealing edge19a. The second sealing sliding surface19abuts a second sliding surface9of the pump housing2. The first sealing sliding surface18is arranged circumferentially next to the first circumferential portion counter to the rotational direction of the delivery rotor5. The second sealing sliding surface19is arranged circumferentially next to the second circumferential portion13in the rotational direction of the delivery rotor5.

The transition15has a distance from the first sealing edge18aas measured in the circumferential direction which is greater than or equal to a distance from the second sealing edge19aas measured in the circumferential direction. In the example embodiment shown inFIG.1, the distance between the transition15and the first sealing edge18aas measured in the circumferential direction is greater than the distance between the transition15and the second sealing edge19aas measured in the circumferential direction.

The distance between the transition15and the first sealing edge18aas measured in the circumferential direction is greater than the maximum circumferential extent of two adjacent delivery cells6a. In other words, the distance between the transition15and the first sealing edge18aas measured in the circumferential direction is greater than the maximum circumferential distance between the two outermost delivery means6of a total of three adjacent delivery means6. Irrespective of this, the distance between the transition15and the first sealing edge18aas measured in the circumferential direction is smaller than the maximum circumferential extent of three adjacent delivery cells6a. The distance between the transition15and the first sealing edge18aas measured in the circumferential direction is smaller than the maximum circumferential distance between the two outermost delivery means6of a total of four adjacent delivery means6.

The distance between the transition15and the second sealing edge19aas measured in the circumferential direction is greater than the maximum circumferential extent of a delivery cell6a. In other words, the distance between the transition15and the second sealing edge19aas measured in the circumferential direction is greater than the maximum circumferential distance between two adjacent delivery means6. Irrespective of this, the distance between the transition15and the second sealing edge19aas measured in the circumferential direction is smaller than the maximum circumferential extent of two adjacent delivery cells6a. The distance between the transition15and the second sealing edge19aas measured in the circumferential direction is smaller than the maximum circumferential distance between the two outermost delivery means6of a total of three adjacent delivery means6.

The first sealing sliding surface18preferably spans a first imaginary plane18′, and the second sealing sliding surface19spans a second imaginary plane19′ both shown inFIG.3. The two imaginary planes18′ and19′ extend parallel to each other in the movement direction of the setting element10. In the example embodiment, the second imaginary plane19′ is offset in parallel in relation to the first imaginary plane18′. The second imaginary plane19′ in particular exhibits an orthogonal distance from the rotational axis D which is greater than the orthogonal distance between the first imaginary plane18′ and the rotational axis D. In alternative example embodiments, the two planes18′ and19′ can however also be arranged congruently with each other. Both imaginary planes18′ and19′ extend between the rotational axis D of the delivery rotor5and the transition15in any position of the setting element10.

For better comprehension, the sectional representation of the rotary pump1shown inFIG.1is shown in a perspective representation inFIG.2. For an explanation of the structure and functionality of the rotary pump1depicted inFIG.2, reference is made to the statements made above.

FIG.3shows a perspective representation of the setting element10of the example embodiment. The setting element10can however also be used in other rotary pumps having an adjustable delivery volume. The setting element10preferably consists of one part and can in particular be molded in one piece.

The setting element10is delineated on the radially outer side by an outer surface area17and on the radially inner side by an inner surface area16. Two pressure surfaces21are also embodied on the setting element10, on each of which a restoring means7of the rotary pump1can be supported (the restoring means7not being shown inFIG.3). In alternative embodiments, the setting element10can also comprise only one pressure surface21or more than two pressure surfaces21.

The first sealing sliding surface18and the second sealing sliding surface19are visible in the perspective view shown inFIG.3. The setting element10comprises two other sealing sliding surfaces, which are preferably each embodied in a similar way to the first sealing sliding surface18and the second sealing sliding surface19, on the opposite side of the setting element10, i.e. on the side of the high-pressure outlet.

The edge of the first sealing sliding surface18which faces the first circumferential portion11forms the first sealing edge18a. The edge of the second sealing sliding surface19which faces the second circumferential portion13forms the second sealing edge19a.

The first circumferential portion11exhibits an axial width B1which is smaller than the axial width B2of the second circumferential portion13. The first circumferential portion11is separated from the second circumferential portion13in the circumferential direction by the transition15.

The first circumferential portion11is formed by at least one recess12or, as in the example embodiment shown, by two axially opposing recesses12. The recess12comprises a recess base12a. The edge12cwhich connects the outer surface area17to the recess base12ais preferably rounded and/or exhibits a radius. A rounded edge12ccauses a less turbulent radial flow of the fluid to be delivered from the low-pressure inlet3into the delivery region of the rotary pump1. The recess base12ais respectively delineated in the circumferential direction by a recess wall12b. The recess wall12barranged in the rotational direction of the delivery rotor5simultaneously forms the transition15.

The transition15is a collar15of the setting element10. The collar15extends perpendicularly from the first circumferential portion11, in particular from the recess base12a, in the axial direction.

The second circumferential portion13, which is adjacent in the rotational direction of the delivery rotor5, exhibits a width B2which corresponds to the axial width B6of the delivery means6. The second circumferential portion13comprises a cavity14on the side of the inner surface area16. The cavity14extends in the circumferential direction from the first circumferential portion11and/or from the transition15up to a wall14a.

In the example embodiment of the setting element10shown inFIG.3, a pressure cavity25is provided in the second sealing sliding surface19. When the setting element10is installed, the pressure cavity25is connected in fluid communication with the pressure chamber24via a channel26.

For better comprehension, the setting element10is shown in a plan view inFIG.4.FIG.5andFIG.6show the sections of the setting element10indicated inFIG.4. With regard to the specific structure of the setting element10, reference is made to the statements made above.

FIG.7shows a detail of a lateral view of the rotary pump1. In the detail shown inFIG.7, the viewer is looking into the pump housing2through the low-pressure inlet3in the flow direction of the fluid to be delivered.

The fluid to be delivered enters the inlet channel3bof the low-pressure inlet3via the fluid port3a. A first part of the inflowing fluid can flow directly, preferably in the radial direction, towards the setting element10, in particular towards the outer surface area17of the setting element10. The fluid can flow into the delivery region, in particular radially or at least with a radial direction component, via the first circumferential portion11and delivered by the delivery means6.

The second circumferential portion13adjoins the first circumferential portion11in the rotational direction of the delivery rotor5. The second circumferential portion13exhibits an axial width which corresponds to the axial width of the delivery means6. The second circumferential portion13thus 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.

A second part of the inflowing fluid hits the flow channeling structure22. The flow channeling structure22directs a sub-flow of the second part of the fluid into the first inlet sub-channel3c. Another sub-flow of the second part of the fluid is directed into the second inlet sub-channel3dby the flow channeling structure22.

In the example embodiment, the first circumferential portion11is arranged axially next to and in particular also axially above the first inlet sub-channel3cin any position of the setting element10. The second circumferential portion13is arranged axially next to and in particular also axially above the second inlet sub-channel3din any position of the setting element10. Depending on the position of the setting element10, the transition15is arranged axially next to and in particular axially above either the flow channeling structure22and/or the second inlet sub-channel3d.

REFERENCE SIGNS