SCREW PUMP

Description

[0001] The invention relates to a screw spindle pump, with a spindle housing in which a drive spindle and at least one running spindle meshing with the drive spindle are accommodated in spindle bores, and with an outer housing enclosing the spindle housing, on which an axial inlet connection and a radial outlet connection are provided.

[0002] Such a screw spindle pump is used to pump a fluid and is used in a wide variety of areas. An example is the pumping of fuel or other operating or supply fluid, such as a coolant or cleaning agent, in a motor vehicle. Such screw spindle pumps can also be used in other land or air vehicles such as airplanes or drones, although the possible applications are not limited to this. Such a screw spindle pump has a spindle housing, which can also be referred to as an inner housing, in which at least two spindles, namely a drive spindle and a running spindle, are accommodated in respective spindle bores which, however, intersect one another. The drive spindle and the running spindle each have a spindle profile, whereby the two spindle profiles mesh with one another.The drive spindle is connected to a drive motor and can be actively rotated, which also causes the meshing idler spindle to rotate. The spindle rotation continuously shifts a delivery volume in the direction of the spindle's longitudinal axis, through which the fluid is conveyed. The spindle housing is housed in an outer casing, which can be pot-shaped, for example, and can be closed off on one side by an axial wall, while the drive motor, for example, is flanged to the other side. It is also conceivable, however, for the outer casing to be multi-part and have a cylindrical base section that is closed off on one side by a cover, while the drive motor is flanged to the other side. The outer casing has an axial inlet connection, i.e. a corresponding connecting piece, to which a supply line can be connected, thus defining the suction side.It also has a radial outlet connection, i.e., a corresponding outlet nozzle, which defines the pressure side. The pumped fluid exits there at the respective pressure that can be generated by the pump. Such a pump is described, for example, in DE 10 2018 131 587 A1, DE 10 2018 130 472 A1, and DE 10 2005 025 816 A1.

[0003] In the known pump, an axial inlet connection is provided off-center on the outer housing, through which the inlet takes place. The fluid then initially flows laterally towards an axial inlet opening of the spindle housing, is conveyed through it, and leaves the spindle housing at a radial housing bore, from where it flows via a narrow connecting space between the spindle housing and the outer housing to the radial outlet connection. In the area of ​​this radial outlet bore of the spindle housing and the narrow connecting space, i.e. the pressure side, the conveyed fluid is present at a correspondingly high pump pressure, so that a high local pressure is exerted on the spindle housing or in the intermediate housing area where the narrow connecting space is provided.

[0004] The invention is based on the problem of providing an improved screw spindle pump.

[0005] To solve this problem, according to the invention, a screw spindle pump as described in the introduction is provided, in which the spindle housing has an axial fluid outlet for the fluid conveyed through the spindle housing via the drive spindle and the idler spindle, which fluid outlet communicates with a fluid chamber formed between the spindle housing and the outer housing and extending through 360°, which in turn communicates with the radial outlet.

[0006] In the screw spindle pump according to the invention, a radial fluid chamber is particularly advantageously provided between the spindle housing and the outer housing, which runs 360° around the spindle housing, thus surrounding it as an annular chamber. This annular fluid chamber is located on the pressure side and is therefore a pressure chamber, since the pressurized fluid emerging from the spindle housing is supplied to it. This fluid exits the spindle housing axially, which means that a correspondingly large, axial fluid outlet opening is provided on the spindle housing so that the fluid pumped axially along the spindle assembly can easily exit axially. No radial bores or similar configurations are required on the spindle housing side. The axial fluid outlet of the spindle housing communicates with the radial fluid or pressure chamber, which means that the pressurized fluid is appropriately deflected and supplied to the radial fluid chamber.

[0007] Since, as described, this radial fluid or pressure chamber completely surrounds the inner housing, i.e., circumferentially by 360°, the corresponding pump pressure is particularly advantageously applied on all sides of the inner housing, which means that ultimately almost symmetrical pressure conditions are present at the spindle housing or load is applied to it. On the one hand, this avoids local pressure increases, such as those resulting from an asymmetric pressure distribution, as known from the prior art. On the other hand, deformations of the spindle housing, albeit slight, resulting from the fluid pressure that also builds up in the spindle housing are avoided, since, as described, the spindle housing is loaded radially on the outside with the fluid pressure prevailing in the fluid chamber and is therefore stabilized. This means that, according to the invention, a fluid jacket is particularly advantageously realized which creates a corresponding radial pressure that stabilizes the inner housing.This is particularly advantageous if the spindle housing is made of a somewhat softer material, such as plastic, which can certainly be the case with smaller screw spindle pumps, which can nevertheless generate correspondingly high pump pressures.

[0008] The fluid chamber provided according to the invention extends, as described, 360° around the spindle housing. It should also encompass the spindle housing over at least part of its axial length. The fluid chamber should extend at least half the length of the spindle bore or spindle housing, or even longer if necessary, for example, approximately two-thirds the length of the spindle bores or spindle housing. It is also conceivable for the fluid chamber to extend the entire length of the spindle bores or spindle housing.Due to the axial exit of the fluid from the spindle housing, which among other things also leads to a reduction of any flow noise and is therefore also advantageous, and the necessary deflection in the direction of the fluid chamber, the fluid chamber ultimately begins at the pressure-side end of the spindle housing and then extends axially to the suction-side end, whereby the fluid chamber extends over at least half the length, preferably even longer, of the spindle housing.

[0009] The spindle housing must be supported accordingly in the outer housing, and of course the fluid chamber must also be sealed axially. Various design options are conceivable for this. According to a first alternative, the fluid chamber can be axially delimited by two radial flanges, one of which has several axial openings through which the fluid chamber is connected to the fluid outlet of the spindle housing. The spindle housing is accommodated in the outer housing via these radial flanges and is radially supported. The radial flange provided on the pressure side has corresponding openings that allow the fluid flowing axially out of the spindle housing to flow axially back into the fluid chamber after being deflected. Sealing on this side is of course not necessary.The other radial flange, which is provided on the suction side, serves for sealing, for which purpose one or more suitable sealing means are provided in this area, by means of which the spindle housing is sealed to the outer housing, so that the fluid chamber is also sealed at this suction-side end.

[0010] As an alternative to the design of two radial flanges, it is also conceivable to axially define the fluid chamber by means of a radial flange, on the one hand, which has a plurality of axial openings through which the fluid chamber is connected to the fluid outlet of the spindle housing, and on the other hand, by means of a cover component. In this case, only one radial flange provided on the pressure side is used, which, as in the embodiment described above, has axial openings to enable the return flow of the pumped, pressurized fluid into the fluid chamber. The other side of the fluid chamber is closed or defined by a cover component placed on the cylindrical base part of the outer housing. While in the first variant the suction-side radial flange defines the chamber, in the second variant the axial chamber definition is achieved via the cover component.

[0011] As described, the fluid flowing axially out of the spindle housing is to be redirected and returned radially outwards into the fluid chamber. The fluid outlet is ultimately realized via the axially open side of the spindle housing, which is preferably accommodated centrally or centrally in the outer housing. In order to realize the redirection and return flow in a simple manner, an expedient further development provides for the arrangement of an intermediate component placed on the outer housing, which is designed to connect a drive motor, wherein one or more deflection cavities are formed on the intermediate component, which deflect the fluid coming from the fluid outlet of the spindle housing to the fluid chamber. This intermediate component, which can also be referred to as an adapter or adapter flange, is placed axially on the outer housing and fixed thereto.On the other hand, it also forms the mounting interface for the drive motor, which is axially mounted on the intermediate component and whose drive shaft runs through the intermediate component to a suitable coupling, via which the drive shaft is coupled to the drive spindle of the spindle assembly. According to the invention, one or more deflection cavities are provided on this intermediate component. These cavities are one or more recesses, depressions, or spaces into which the fluid flowing axially out of the spindle housing enters. These recesses extend radially outward and, in turn, communicate with the fluid chamber, for example, via the several openings provided on the pressure-side radial flange of the spindle housing.Via this one or more deflection cavities, it is possible to deflect the axially escaping fluid radially outwards around the entire circumference and axially back into the fluid chamber, so that the chamber inflow occurs not only locally but ultimately around the entire chamber circumference.

[0012] The intermediate component can be sealed from the drive motor or the drive shaft running through the intermediate component. This is possible using a shaft seal, so that no fluid flows into the drive motor to cool it. In this case, the drive motor would be a dry-running motor. If no seal, i.e., no shaft seal, is provided, a small portion of the fluid can flow into the drive motor, circulate there, and flow back again, thus simultaneously allowing motor cooling. In this case, the drive motor would be a wet-running motor.

[0013] However, the interposition of such an intermediate component is not absolutely necessary. Alternatively, it is also possible to provide one or more deflection cavities on the housing of a drive motor that is mounted on the outer housing. These deflection cavities divert the fluid coming from the fluid outlet of the spindle housing to the fluid chamber. In this case, the motor housing is mounted directly on the outer housing and connected to it, so that the fluid emerging from the spindle housing flows directly against the motor housing, on which the one or more deflection cavities are formed. Here, too, it is possible to design the drive motor as a dry-running motor, in which case the drive shaft leading out of the motor housing is sealed on that side by a shaft seal. In a wet-running motor design, no shaft seal would be provided, allowing a certain amount of fluid to flow into the drive motor for cooling purposes.

[0014] Preferably, a deflection cavity is provided in the form of an annular groove or pot-shaped depression, which is preferably rounded in the area of ​​the groove or depression base. This means that the intermediate component or the end wall of the motor housing is designed with a corresponding, annular and 360° circumferential annular groove or concave or dome-shaped depression, which enables fluid deflection on all sides. This easily ensures a symmetrical fluid flow into the fluid chamber. Of course, the groove can also be divided into individual groove sections via axially and radially extending webs if such webs are provided, for example, for stabilization purposes.

[0015] The fluid chamber itself, as already described, is sealed from the outer housing by one or more sealing elements. This or these sealing elements can be provided in different positions depending on the housing design. If the fluid chamber is axially limited at the suction end by a radial flange of the spindle housing, a first sealing element can be accommodated in a receiving groove on the radial flange of the spindle housing or outer housing adjacent to the inlet connection and seals the spindle housing to the outer housing. A second sealing element serves to seal the pressure side. Different variants are conceivable here. For example, a second sealing element can be accommodated in a receiving groove in the intermediate component and seals the intermediate component to the outer housing.If such a seal is not used, but the drive motor is flanged directly to the outer housing, a second sealing element can be accommodated in a groove in the drive motor housing and seal the motor housing to the outer housing. Sealing rings made of a suitable elastomer are advantageously used as sealing elements.

[0016] If sealing or axial limitation on the suction side is not provided by a radial flange, but rather by a cover component, an alternative pump design can feature a first sealing element housed in a groove on the spindle housing or on the cover component, sealing the spindle housing to the cover component. This creates a first sealing plane between the cover component and the spindle housing. Furthermore, a second sealing element can be housed in a groove on the outer housing or on the cover component, sealing the outer housing to the cover component. This creates the second sealing plane between the cover component and the outer housing.

[0017] As already described for the previous embodiment, two variants are conceivable for the pressure-side seal. For example, a third sealing element can be accommodated in a receiving groove of the intermediate component or the outer housing, sealing the intermediate component to the outer housing. If no such intermediate component is used, a third sealing element can be accommodated in a receiving groove of a motor housing of the drive motor, sealing the motor housing to the outer housing.

[0018] As described, the fluid or pressure jacket implemented according to the invention via the fluid chamber enables the targeted generation of all-round, radial stabilizing pressure on the spindle housing in order to avoid widening of the tolerances on the spindle housing or any minor operational changes in the geometry. This is particularly the case when the spindle housing is made of plastic, as can be provided according to the invention. Additionally or alternatively, it is also conceivable to manufacture the outer housing, the intermediate component and / or the cover component from plastic. This means that it is possible to manufacture all housing-relevant components from plastic, just as it is fundamentally possible to manufacture the spindles themselves from plastic. Preferably, however, at least these are made of metal.

[0019] As already described, the screw spindle pump can have a drive motor which is coupled to the drive spindle by means of a drive shaft and which is either designed as a dry rotor, wherein the drive spindle is radially sealed by a shaft seal, or which is designed as a wet rotor, wherein a part of the fluid axially emerging from the spindle housing flows along the drive shaft into the drive motor.

[0020] The screw pump can be a 2-spindle pump with only one drive spindle and a side-mounted idler spindle. Alternatively, it is also conceivable for the screw pump to be a 3-spindle pump with a central drive spindle and two idler spindles arranged on either side of it, offset by 180°. Thus, different pump types can be realized with the fluid or pressure chamber according to the invention around the inner housing.

[0021] Furthermore, it can be provided that the inlet connection is aligned with a central axis of the spindle assembly comprising the drive spindle and one or two idler spindles. This means that the inlet nozzle is arranged as an axial extension of the central axis of the spindle assembly. In a 2-screw pump, this central axis is ultimately located centrally between the drive spindle and the idler spindle. In a 3-screw pump, this central axis lies in the longitudinal axis of the central drive spindle. This design has the particular advantage that the inflowing, axially sucked-in fluid does not first have to be deflected within the outer housing towards the spindle housing, which can be associated with flow noise. Instead, a direct axial flow from the inlet connection into the spindle housing is possible.

[0022] In addition to the screw pump itself, the invention further relates to the use of a screw pump of the type described above in a motor vehicle for pumping an operating fluid. This operating fluid can be of any nature. It can be a cleaning fluid, for example a windshield washer fluid, which is pumped via the pump. Alternatively, and a preferred use according to the invention, the screw pump can be used as a coolant pump, via which a coolant is pumped. The coolant can be any fluid coolant. The use relates in particular to the use for pumping a coolant used to cool an energy storage device. Such an energy storage device is increasingly used in electric motor-driven vehicles and is provided in the form of a correspondingly dimensioned traction or drive battery.This energy storage device requires appropriate cooling by means of a coolant, which can be easily pumped in the required quantity using the screw pump according to the invention.

[0023] Further advantages and details of the invention will become apparent from the following exemplary embodiments and the accompanying drawings. These schematically show: Fig. 1 a schematic diagram of a screw pump according to the invention of a first embodiment in a sectional view, Fig. 2 the screw pump from Fig. 1 with flow arrows drawn in, Fig. 3 an exploded view of the screw pump from the Figures 1 and 2 , Fig. 4 a partial view of a screw pump according to the invention of a further embodiment in a partially sectioned perspective view, Fig. 5 a partial view of the arrangement of Fig. 4in a longitudinal section through the intermediate component provided in this embodiment, Fig. 6 a view corresponding Fig. 5 in a cross-section, and Fig. 7 a perspective view of a screw pump according to the invention of a further embodiment.

[0024] Fig.1 shows a screw spindle pump 1 according to the invention in a first embodiment. This comprises a spindle housing 2, in which, in the example shown, three spindles are located, namely a drive spindle 3 and two idler spindles 4 positioned laterally offset by 180° next to the drive spindle 3, which are accommodated in corresponding, intersecting spindle bores. Fig. 1 shows, all spindles have corresponding spindle profiles that interlock and mesh with each other.

[0025] The spindle housing 2 is housed in a pot-shaped outer housing 5, on which an inlet connection 6, i.e. a corresponding connection piece, is provided, positioned centrally and in alignment with the longitudinal axis of the drive spindle 3. The spindle assembly consisting of the drive spindle 3 and the idler spindles 4 is axially supported by a support element, in this case a key 8, relative to the outer housing 5 or its radial flange 7.

[0026] Furthermore, a radial outlet connection 9, also a connection piece, is provided on the outer housing 5, through which the fluid sucked in via the inlet connection 6 and under pressure exits radially again.

[0027] How Fig. 1 clearly shows, the spindle housing 2 and its components are accommodated inside the pot-shaped outer housing 5. Between the outer wall of the inner housing 2 and the inner wall of the outer housing 5, a fluid chamber 10 is provided which, as Fig. 1 shows, extends by more than half the length of the spindle housing 2 or the spindle bores. The pressurized fluid exiting the axial fluid outlet of the spindle housing 2 enters this fluid chamber 10, meaning that the axial fluid outlet at the left end of the spindle housing 2 communicates with the fluid chamber 10. This, in turn, communicates with the outlet connection 9.

[0028] Furthermore, a drive motor 11, only stylized here, is provided, which is mounted directly on the outer housing 5 and secured there. The drive motor 11 is coupled to the drive spindle 3 via a coupling element 13 by a drive shaft 12, also only stylized, so that the spindle can be actively rotated via the drive motor 11, so that the entire spindle assembly rotates and axially conveys the fluid sucked in via the inlet connection 6.

[0029] As described, the fluid exits the axial fluid outlet of the spindle housing 2, which in this embodiment is simply axially open at the pressure-side end. To enable the fluid to reach the fluid chamber, which is axially set back in terms of the conveying direction, a deflection cavity 14 is provided in the example shown, which in the example shown is formed directly on the housing wall of the drive motor 11 facing the spindle housing 2. This deflection cavity 14, which will be discussed below, is designed, for example, as a circumferential annular groove and is curved or rounded on the bottom side, so that the fluid, which flows in virtually centrally, is deflected radially outwards to the side and returned, allowing it to enter the fluid chamber 10 via corresponding openings 15 formed on a radial flange 19 of the spindle housing 2.

[0030] The fluid chamber 10 is axially delimited at the suction-side end by a radial flange 16 of the spindle housing 2. On the one hand, this is axially supported on a housing shoulder 17 of the outer housing. On the other hand, it extends to the inner wall of the outer housing 5 and is sealed to it by a sealing element 18, so that the fluid chamber 10 is closed and sealed at this end. At the opposite, pressure-side end, a radial flange 19 is also provided, but in which the already described openings 15 are formed, so that the fluid chamber 10 is open on this pressure side and the pressurized fluid can flow into the fluid chamber 10 via the deflection cavity 14. The seal on this side is achieved between the outer housing 5 and the motor housing via a suitable sealing element 20, so that an overall fluid-tight encapsulation is provided.

[0031] During operation, the drive spindle 3 is driven by the drive motor 11, causing the entire spindle assembly to rotate. The fluid drawn in through the inlet port 6 is conveyed axially by the spindle profiles of the spindles 3 and 4 engaging with each other, resulting in axially displaced delivery volumes that allow the fluid to be conveyed along the spindle assembly.

[0032] At the pressure-side end of the spindle housing 2, the fluid exits axially, which is advantageous in terms of quiet operation, as it is associated with no significant flow noise. The fluid then enters directly into the deflection cavity 14, as described, for example, an annular groove or concave recess, through which it is deflected radially outward and axially returned, i.e., deflected against the conveying direction of the spindle assembly. It enters the fluid chamber 10 via the openings 15 and via these into the outlet connection 9, where it is discharged.

[0033] As described, the pump pressure prevails in the fluid chamber 10, i.e., the outlet pressure, which can be generated via the screw spindle pump 1, is present in this fluid chamber 10, which surrounds the spindle housing 2 on all sides. This pressure acts radially on all sides on the spindle housing 2, as long as the spindle housing 2 is encompassed by the fluid chamber 10, which can also be referred to as a pressure chamber. As described, this fluid chamber 10 extends over at least half the length of the spindle housing 2, preferably even somewhat longer, so that the spindle housing 2 is optimally stabilized against any pressure-induced geometric changes or tolerance shifts. This applies in particular if the spindle housing 2 is made of plastic, i.e., a material somewhat softer than metal.

[0034] Fig. 2 shows the same representation as Fig. 1, only in this case corresponding flow arrows are drawn to represent the fluid flow. As Fig. 2 shows, the fluid, for example water, fuel, a coolant or similar, is sucked in at the inlet connection 6 and conveyed axially through the spindle housing 2 via the spindle assembly. It exits at the pressure-side end of the open spindle housing 2 and enters the deflection cavity 14, where, supported by the geometry of this deflection cavity, which, as mentioned, is rounded at the bottom, it is deflected radially outwards and against the inflow direction, so that it can flow axially through the openings 15 back into the fluid chamber 10, which it fills on all sides. From this fluid chamber 10, it then reaches the outlet connection 9, where it then flows out under pressure.

[0035] An exploded view of the screw pump 1 from the Figures 1 and 2 is in Fig. 3shown. Starting on the right, the outer housing 5 is shown with its axial inlet connection 6 and its radial outlet connection 9, which has a mounting flange 21 at the end facing the drive motor 11 in the assembled position, which is fastened to a corresponding mounting flange 22 on the motor housing 23 of the drive motor by means of suitable fastening screws 24.

[0036] Shown next is the cross-shaped key 8, on which the drive spindle 3 and the idler spindles 4 are axially supported. The cross-shaped design of the key 8 enables the spindle housing 2 to be mounted in two orientations offset by 90° relative to the outer housing 5, with the spindles 3, 4 being axially supported on the key 8 in each of the two mounting positions.

[0037] Also shown is the spindle housing 2 with its radial flange 16, on which a corresponding receiving groove 25 is formed, in which the sealing element 18 is received, which, in the assembled position, seals against the outer housing 5. The spindle housing 2 is connected to the outer housing 5 via corresponding connecting screws 26, which penetrate corresponding bores 27 in the radial flange 16 and are screwed into threaded bores (not shown in detail) on the outer housing 5.

[0038] Also shown are the drive spindle 3 and the two running spindles 4, which are inserted into the spindle bores 28, which, as Fig. 3 shows, intersect each other, are inserted.

[0039] Also shown is the coupling element 13, which is inserted in a rotationally fixed manner into a corresponding receptacle on the axial end face of the drive spindle 3 and which has a corresponding plug-in receptacle 28 into which a plug-in pin 29 of the drive shaft 12 of the drive motor 11 engages, thus providing a rotationally fixed connection between the drive shaft 12 and the drive spindle 3. Also shown are two support bearings 30 provided on the motor housing 23 in the form of axially projecting pins, which serve to axially support or mount the two running spindles 4. Also shown is an axial flange 31, which is formed on the motor housing 23 and has a corresponding radial groove 23, in which the sealing element 20, which seals against the outer housing 5, is inserted.

[0040] The fluid chamber 10 is delimited from the suction side by the radial flange 16, as described. Also shown is the radial flange 19, which is open via the openings 15, so that the fluid can flow from the deflection cavity 14, which is indicated on the motor housing 23, into the fluid chamber 10.

[0041] Fig. 4 shows a partial view of a screw pump according to the invention of a further embodiment, the structure of which corresponds to the embodiment shown in the Figures 1 - 3. Provided here again is an outer housing 5 with an axial inlet connection 6 and a radial outlet connection 7, as well as a spindle housing 2 with a drive spindle 3 and two idler spindles 4 provided therein. Likewise, a fluid chamber 10 is formed between the inner housing 2 and the outer housing 5, which extends 360° around the spindle housing 2 and, viewed axially, over at least half the length of the spindle housing. Sealing on the suction side is again achieved via a corresponding radial flange 16 and a sealing element 18 received in the groove 25.

[0042] Unlike the embodiment described above, the motor housing 23 is not mounted directly on the mounting flange 21 of the outer housing 5; rather, in this variant, an intermediate component 33 in the form of an intermediate plate is provided, which is placed between the mounting flange 21 and the mounting flange 22. The annular groove-shaped or dome-shaped deflection cavity 14 is formed on this intermediate component 33, which has a corresponding axial flange 34 with which it engages axially in the outer housing 5. The drive motor 11, with its drive shaft 9, passes through a corresponding bore in this intermediate component and, as already described above, is coupled to the drive spindle 3 via a coupling element 13.

[0043] In this variant of the invention, the fluid deflection is realized via the plate-shaped intermediate component 33, on which the deflection cavity 14 is formed. This, in turn, is shaped such that the fluid is conveyed radially outward and deflected counter to the feed direction, so that it can flow into the fluid chamber 10 via the corresponding openings 15 in the radial flange 19 of the spindle housing 2, and the corresponding stabilizing pressure can be built up in the fluid chamber 10.

[0044] The Figures 5 and 6 show two sectional views offset by 90° through the plate-shaped intermediate component 3. As shown, this is screwed to the mounting flange 21 of the outer housing 5 via corresponding fastening screws 35, wherein in this embodiment the sealing element 20 is received in a corresponding annular groove 36 which is formed on the axial flange 34 and seals radially towards the outer housing 5.

[0045] Also shown is the central bore 37 through which the drive shaft 9 extends. The intermediate component 37 also functions as a motor bearing, since the drive shaft is ultimately supported or guided in this bore 37. If a sealing element in the form of a shaft seal is located in this bore 37, axial flow of the fluid flowing into the deflection cavity 14 along the drive shaft 9 is excluded, and the drive motor 11 would then be a dry-running motor. If there is no shaft seal in the bore 37, a small amount of fluid can flow axially along the drive shaft 9 into the drive motor 11 and cool it.

[0046] In the Fig. 5The sectional view shown clearly shows the ring or dome shape of the deflection cavity 14, which has a rounded bottom surface 38 that promotes fluid deflection. The sectional plane here runs through the drive spindle 3, but not through the running spindles 4.

[0047] A sectional view rotated by 90° is shown in Fig. 6 shown, here the sectional plane runs through the drive spindle 4. This sectional view shows the two support bearings 30 in the form of support pins, whereby these support bearings 30 are integrally formed on the intermediate component 33. A running spindle 4 is axially supported on each support bearing 30.

[0048] Fig. 7Finally, a third embodiment of a screw pump 1 according to the invention is shown, comprising an outer housing 5, which here consists of a cylindrical base part 39 and a cover component 40 axially mounted thereon, which closes off the outer housing 5 on the suction side. The drive motor 11 is arranged on the opposite pressure side and can be screwed either directly to the base part 39 or via an intermediate component 33, as also described above.

[0049] Furthermore, a spindle housing 2 is provided, in which only one drive spindle 3 and one running spindle 4 are accommodated. This is therefore, unlike the designs according to the Figures 1 - 6 This is a 2-spindle pump. However, the basic operating principle is the same.

[0050] In this embodiment, the inlet connection 6 is formed on the cover component 40, as is the outlet connection 9. This means that the cover component 40 forms the axial closure on the one hand, but also has the inlet and outlet connections 6, 9 on the other hand.

[0051] For sealing, an axial flange 41 is formed on the cover component 40, with an annular groove 42 into which a sealing element 43 in the form of a sealing ring is inserted. This provides an axial seal to the spindle housing 2.

[0052] A further sealing plane is provided between the cover component 40 and the base part 39. A radially open annular groove 44 is formed on the base part 39, in which a sealing element 45 in the form of a sealing ring is received, which seals radially toward the cover component 40.

[0053] In this variant, too, these sealing structures axially delimit and seal a fluid chamber 10 encircling the spindle housing 2 on the suction side. In this variant, this fluid chamber 10 extends over the entire length of the spindle housing 2 because, as already described for the preceding embodiments, the fluid exits axially at the axially open, pressure-side end of the spindle housing 2 and is redirected via the deflection cavity 14 and guided back into the fluid chamber 10. As described, the deflection cavity 14 can be formed either directly on the corresponding bottom wall of the motor housing 23 or on the plate-shaped intermediate component 33.

[0054] In any case, a corresponding pressure builds up within the fluid chamber 10, which acts radially on all sides of the spindle housing 2. The fluid chamber 10 naturally also communicates with the outlet connection 9, as Fig. 7 clearly shows.

Claims

1. Screw spindle pump having a spindle housing (2), in which a drive spindle (3) and at least one running spindle (4) which meshes therewith are received in spindle bores (28), characterized by an outer housing (5) which encloses the spindle housing (2) and on which an axial inlet port (6) and a radial outlet port (9) are provided, wherein the spindle housing (2) has an axial fluid outlet for the fluid delivered through the spindle housing (2) by the drive spindle and the running spindle (3, 4), which axial fluid outlet communicates with a fluid chamber (10), which is formed between the spindle housing (2) and the outer housing (5), extends around 360°, and in turn communicates with the radial outlet port (9).

2. Screw spindle pump according to Claim 1, characterized in that the fluid chamber (10) extends over at least half the length of the spindle bore (23).

3. Screw spindle pump according to Claim 1 or 2, characterized in that the fluid chamber (10) either is axially delimited by two radial flanges (16, 19), wherein the one radial flange (19) has multiple axial apertures (15) via which the fluid chamber (10) is connected to the fluid outlet of the spindle housing (2), or in that the fluid chamber is axially delimited on one side by a radial flange (19), which has multiple axial apertures (15) via which the fluid chamber (10) is connected to the fluid outlet of the spindle housing (2), and on the other side by a cover component (40).

4. Screw spindle pump according to one of the preceding claims, characterized in that an intermediate component (33) fitted on the outer housing (5) and designed for the attachment of a drive motor (11) is provided, wherein one or more deflection cavities (14) which deflect the fluid coming from the fluid outlet of the spindle housing (2) toward the fluid chamber (10) are provided on the intermediate component (33).

5. Screw spindle pump according to one of Claims 1 to 3, characterized in that one or more deflection cavities (14) which deflect the fluid coming from the fluid outlet of the spindle housing (2) toward the fluid chamber (10) are provided on a housing (23) of a drive motor (11) fitted on the outer housing (5).

6. Screw spindle pump according to Claim 4 or 5, characterized in that the one deflection cavity (14) is an annular groove or pot-like depression, which has a round configuration in the region of the groove or depression base.

7. Screw spindle pump according to one of the preceding claims, characterized in that the fluid chamber (10) is sealed with respect to the outer housing (5) by one or more seal elements (18, 20, 36, 43, 45).

8. Screw spindle pump according to Claim 3 and Claim 4, 5 or 6, and Claim 7, characterized in that a first seal element (18) is received in a receiving groove (25) on the radial flange (16), adjacent to the inlet port (6), of the spindle housing (2) or of the outer housing (5) and seals the spindle housing (2) with respect to the outer housing (5), and in that a second seal element (20) is received in a receiving groove (36) of the intermediate component (33) and seals the intermediate component (33) with respect to the outer housing (5), or in that a second seal element (20) is received in a receiving groove (32) of a motor housing (23) of the drive motor (11) and seals the motor housing (23) with respect to the outer housing (5).

9. Screw spindle pump according to Claim 3 and Claim 4, 5 or 6, and Claim 7, characterized in that a first seal element (43) is received in a receiving groove (42) on the spindle housing (2) or on the cover component (40) and seals the spindle housing (2) with respect to the cover component (40), in that a second seal element is received in a receiving groove (44) on the outer housing (5) or on the cover component (40) and seals the outer housing (5) with respect to the cover component (40), and in that a third seal element (20) is received in a receiving groove (36) of the intermediate component (33) or of the outer housing (5) and seals the intermediate component (33) with respect to the outer housing (5), or in that a third seal element (20) is received in a receiving groove (32) of a motor housing (23) of the drive motor (11) and seals the motor housing (23) with respect to the outer housing (5).

10. Screw spindle pump according to one of the preceding claims, characterized in that the spindle housing (2), the outer housing (5), the intermediate component (33) and / or the cover component (40) are made of plastic.

11. Screw spindle pump according to one of the preceding claims, characterized in that a drive motor (11) is provided, which is coupled to the drive spindle (3) by way of a drive shaft (9), and which either is in the form of a dry-running rotor, wherein the drive shaft (9) is radially sealed by a shaft sealing ring, or which is in the form of a wet-running rotor, wherein some of the fluid axially exiting the spindle housing (2) flows along the drive shaft (9) into the drive motor (11).

12. Screw spindle pump according to one of the preceding claims, characterized in that a central drive spindle (3) and two running spindles (4) arranged on either side of the drive spindle are provided.

13. Screw spindle pump according to one of the preceding claims, characterized in that the inlet port (6) is arranged in line with a central axis of the spindle set comprising the drive spindle (3) and the one or the two running spindles (4).

14. Use of a screw spindle pump (1) according to one of the preceding claims in a motor vehicle for the purpose of delivering an operating liquid.

15. Use according to Claim 14, characterized in that the screw spindle pump (1) is used as a coolant pump, in particular for delivering a coolant serving to cool an energy store.