DE102018220811A1 - Device for conveying a cooling fluid - Google Patents

Abstract

Device for conveying a cooling fluid, with a screw pump, which comprises a pump housing and a spindle screw rotatably mounted about a first axis of rotation and arranged in an axial passage of the pump housing, and with an electric motor for driving the spindle screw, which has a stator and non-rotatably connected to the pump housing comprises a rotor rotationally coupled to the spindle screw, and vehicle.

Description

The invention relates to a device for conveying a cooling fluid, comprising a screw pump, which comprises a pump housing and a spindle screw which is rotatably mounted about a first axis of rotation and is arranged in an axial passage of the pump housing, and an electric motor for driving the spindle screw, which is connected to the pump housing rotatably connected stator and a rotor rotatably coupled to the spindle screw. The invention further relates to a vehicle.

Devices with spindle screws are known in the prior art in different configurations. They are used in the form of spindle drives, for example, to transform a rotational movement into a translational movement.

So the reveals DE 102 35 078 A1 a spindle drive for an unspecified mechanical application. The spindle drive comprises an electric motor with a stator and a rotor which is mounted in the stator so as to be rotatable about an axis of rotation and is designed as a hollow shaft. Furthermore, the spindle drive comprises a spindle screw which extends through the rotor in an axial direction and is rotatably mounted in a spindle nut which is connected to the rotor in a rotationally fixed manner. At one axial end of the spindle screw, a joint head for connecting an application is attached in a rotationally fixed manner. Rotation of the rotor shifts the spindle screw and thus the joint head in the axial direction, whereby the application connected to the joint head is actuated.

A further field of application are devices for conveying a fluid, which comprise a screw pump with a flow channel and a displacement element in the form of a spindle screw which is rotatably mounted in the flow channel about an axis of rotation. When the spindle screw rotates, a fluid arranged in the flow channel is conveyed in an axial direction.

Such a device for conveying fuel for a vehicle discloses the DE 43 00 512 B4 . The device comprises an electric motor with a stator and a rotor which is rotatably mounted in the stator about an axis of rotation, and a spindle screw which extends through the rotor and which is rotatably mounted in the rotor by means of a plurality of rolling elements and has a piston at one axial end. Rotation of the rotor moves the spindle screw and thus the piston in an axial direction, whereby a fuel is delivered.

The DE 199 49 082 B4 discloses another fuel delivery device for an internal combustion engine. The device can be arranged in a tank of an internal combustion engine and comprises an electric motor with a stator and a bell-shaped rotor which is rotatably mounted about an axis of rotation in a housing of the stator and a screw pump arranged in the rotor. The screw pump comprises a pump housing which is connected to the stator in a rotationally fixed manner, a spindle screw and a running spindle which engages in the spindle screw and which are arranged in the pump housing. The spindle screw is rotatably mounted in the pump housing about the axis of rotation and rigidly connected to the rotor of the electric motor. During the operation of the device, the spindle screw rotates synchronously with the rotor and delivers fuel, the fuel also flowing through the electric motor.

Such devices for conveying a liquid fuel or fuel are designed for a high fluid pressure and a low volume flow. In contrast, a device for conveying a cooling fluid, for example for a vehicle for conveying a cooling liquid such as water, must be designed for a high volume flow in order to ensure the cooling effect of the cooling fluid.

The first-mentioned device does not allow a constantly high volume flow and requires a relatively large amount of axial installation space, while in the latter device a high volume flow that is possible in principle when flowing through the electric motor leads on the one hand to turbulence in the cooling fluid, which leads to a pressure loss in the cooling fluid and a strong noise development, i . H. acoustic emission, and on the other hand causes the electric motor to corrode.

Noise, a pressure loss in the cooling fluid or corrosion of the electric motor are undesirable because they are perceived as annoying by a person or can reduce the efficiency and / or the service life of the device.

The invention is therefore based on the object of providing an improved device for conveying a cooling fluid which avoids the disadvantages described. In addition, it is an object of the invention to provide a vehicle with a device for conveying a cooling fluid.

An object of the invention is a device for conveying a cooling fluid, with a screw pump, which has a pump housing and a bearing which is rotatable about a first axis of rotation comprises a spindle screw arranged in an axial passage of the pump housing, and with an electric motor for driving the spindle screw, which comprises a stator that is non-rotatably connected to the pump housing and a rotor that is rotationally coupled to the spindle screw. The conveying device can be installed, for example, as a cooling water pump in a motor vehicle.

In the device according to the invention, the rotor is rotatably mounted on the pump housing about a second axis of rotation parallel and spaced apart from the first axis of rotation and axially penetrated by the spindle screw. The second axis of rotation can accordingly be referred to as the rotor axis of rotation. In this way, the stator of the electric motor can be encapsulated with respect to the flowing cooling fluid, whereby the stator is protected against corrosion by the cooling fluid. Since the rotor of the electric motor is also arranged at a distance from the flowing cooling fluid, the electric motor does not cause turbulence in the cooling fluid, so that pressure loss in the cooling fluid and noise in the flowing cooling fluid are avoided. In addition, the device requires a very small installation space in relation to the axial direction.

In an advantageous embodiment, the screw pump comprises a running spindle which is arranged in the pump housing and rotatably mounted about a third axis of rotation parallel to and spaced from the first axis of rotation and the second axis of rotation and which engages with the spindle screw. In addition to the screw, the spindle forms a further displacement element and can be driven by the screw, thanks to the mutual engagement. H. only the screw of the screw pump is driven by the electric motor.

In a preferred embodiment, the pump housing has a cylindrical shape and the rotor is designed as a hollow cylinder and comprises a roller bearing, by means of which the rotor of the electric motor is mounted on a peripheral surface of the pump housing. In other words, the rotor can rotate along the circumferential surface of the pump housing. The rolling bearing can comprise spherical or cylindrical rolling elements.

In further embodiments, the stator comprises a stator housing, within which the pump housing is arranged and which defines an inflow opening, an outflow opening and a flow channel connecting the inflow opening to the outflow opening for a cooling fluid, which extends through the axial passage of the pump housing. The respective cross-sectional areas of the inflow opening, the axial passage and the outflow openings can be designed in accordance with a required volume flow.

A cross-sectional area of the inflow opening and a cross-sectional area of the outflow opening are preferably circular, have an identical surface area and are centered with respect to the second axis of rotation. Circular inflow and outflow openings correspond to cylindrical fluid connections of the device, as a result of which connection of usually cylindrical cooling fluid lines, for example cooling hoses or cooling pipes, of a cooling circuit is easily possible.

In advantageous embodiments, an axial projection of a cross-sectional area of the axial passage of the pump housing into a plane of the cross-sectional area of the inflow opening or the outflow opening is completely contained in the cross-sectional area of the inflow opening or the outflow opening. In other words, the axial passage does not protrude in the radial direction from the inflow opening or the outflow opening. As a result, the inflow opening or the outflow opening limit a maximum cross-sectional area of the axial passage, while a volume flow of the cooling fluid depends on the possibly smaller cross-sectional area of the axial passage.

In preferred embodiments, the device comprises a gearwheel rotatably mounted on the stator housing and / or on the pump housing and, in the device, the rotor projects axially over the pump housing in the direction of the drain opening and the rotor has an internal toothing in an edge region facing the drain opening Spindle screw on an axial end facing the drain opening on an external toothing, which are each in engagement with the gear. For example, the gearwheel can be mounted in a radial bearing provided on the pump housing and / or the stator housing by means of a central bore on a cylindrical axis fastened to the pump housing and / or the stator housing, or a shaft rotatably connected to the gearwheel. There is therefore no rigid rotational coupling between the spindle screw and the rotor. Rather, the rotational coupling is mediated by the gear. Because of the gearwheel, a rotational speed of the spindle screw can therefore deviate from a rotational speed of the rotor, which allows an adjustment of a volume flow of the cooling fluid.

In the axially projecting edge region, the rotor particularly preferably has a radially inwardly pointing annular projection on which the internal toothing is formed. In this way, a circumference of the internal toothing is reduced, so that an identical one External toothing of the spindle screw, the gear has a smaller diameter and correspondingly fewer teeth, which is associated with a larger ratio. The volume flow of the cooling fluid can be flexibly adjusted with a radial width of the annular projection.

In a further preferred embodiment, the gearwheel is arranged such that an axial projection of the gearwheel into a plane of a cross-sectional area of a drain opening of a stator housing of the stator is arranged outside the cross-sectional area of the drain opening. In other words, the gear does not protrude into the flow channel. This avoids turbulence in the cooling fluid and a reduction in the volume flow through the gear.

The invention also relates to a vehicle with a cooling circuit, which comprises an inventive device for conveying a cooling fluid. Thanks to the conveyor device according to the invention, the vehicle has efficient and long-lasting cooling, which also low noise, i. H. low acoustic emissions.

An essential advantage of the device according to the invention is that it simultaneously enables a high cooling capacity, a long service life and low noise during operation.

• 1 in einer schematischen Darstellung eine radiale Schnittansicht einer Vorrichtung zum Fördern eines Kühlfluids nach einer Ausführungsform der Erfindung;
• 2 in einer schematischen Darstellung eine Querschnittansicht der in 1 gezeigten Vorrichtung auf die mit II-II bezeichnete Schnittebene in Pfeilrichtung.

The invention is illustrated schematically using an embodiment in the drawings and is further described with reference to the drawings. It shows:

• 1 a schematic representation of a radial sectional view of a device for conveying a cooling fluid according to an embodiment of the invention;
• 2nd in a schematic representation, a cross-sectional view of the in 1 shown device on the with II-II designated cutting plane in the direction of the arrow.

1 shows a schematic representation of a radial sectional view of a device 1 for conveying a cooling fluid according to an embodiment of the invention. The device 1 can, for example, be installed in a vehicle, not shown, as part of a cooling circuit in which water circulates as the cooling fluid.

The device 1 includes a screw pump 10th . The screw pump 10th comprises a sectionally cylindrical pump housing 11 , which has a cylindrical shape and an axial passage 13 having.

The device 1 also includes a spindle screw 12 . The spindle screw 12 is about a first axis of rotation 2nd rotatably mounted and in the axial passage 13 of the pump housing 11 arranged.

The screw pump 10th further includes one about the first axis of rotation 2nd parallel and spaced third axis of rotation 4th rotatable spindle 14 which in the radial passage 13 of the pump housing 11 arranged and with the spindle screw 12 is engaged.

The device further comprises 1 an electric motor 20th for driving the spindle screw 12 . The electric motor 20th includes one with the pump housing 11 non-rotatably connected stator 30th which has one or more coil windings 32 carries, and one with the spindle screw 12 rotationally coupled rotor 40 , which one or more permanent magnets 41 wearing.

The stator 30th of the electric motor 20th includes a stator housing 31 , inside of which the pump housing 11 is arranged and which is an inflow opening 33 , a drain opening 34 and the inlet opening 33 with the drain opening 34 connecting flow channel 35 defined for a cooling fluid which passes through the axial passage 13 of the pump housing 11 extends.

A cross-sectional area of the inflow opening 33 and a cross-sectional area of the drain opening 34 are circular, have an identical surface area and are related to the second axis of rotation 3rd , i.e. the rotor axis of rotation, is centered. In addition, there is an axial projection of a cross-sectional area of the axial passage 13 of the pump housing 11 into a plane of the cross-sectional area of the inflow opening 33 or the drain opening 34 completely in the cross-sectional area of the inflow opening 33 or the drain opening 34 contain.

The rotor 40 of the electric motor 20th is from the spindle screw 12 axially penetrated and on the pump housing 11 about one to the first axis of rotation 2nd and the third axis of rotation 4th parallel and spaced second axis of rotation 3rd rotatably mounted. In other words, the axes of rotation extend 2nd , 3rd , 4th in pairs parallel and spaced from each other, ie are not arranged coaxially. The rotor 40 is designed as a hollow cylinder and by means of a roller bearing 50 the device 1 on a peripheral surface of the pump housing 11 stored.

The rotor 40 stands over the pump housing 11 towards the drain opening 34 axially in front and points in one to the drain opening 34 facing edge area an internal toothing 42 on. In further embodiments, the rotor 40 by doing axially protruding edge region on a radially inwardly facing annular projection on which the internal toothing 42 is trained. Correspondingly, the spindle screw points 12 at one to the drain opening 34 facing axial end an external toothing 15 on.

The device 1 further includes one on the stator housing 31 and on the pump housing 11 rotatable gear 60 . This is the gear 60 penetrated by an axis, the opposite free ends each on the stator 31 and on the pump housing 11 are attached.

The internal toothing 42 of the rotor 40 and the external teeth of the spindle screw are each with the gear 60 engaged. The gear 60 is arranged such that an axial projection of the gear 60 into a plane of a cross-sectional area of a drain opening 34 of a stator housing 31 of the stator 30th outside the cross-sectional area of the drain opening 34 is arranged.

2nd shows a schematic representation of a cross-sectional view of the in 1 shown device 1 on the with II-II designated cutting plane in the direction of the arrow. The device 1 has an essentially rotationally symmetrical structure. The structure comprises the stator housing from radially outside to radially inside 31 who have favourited Coil winding 32 , the permanent magnet 41 , the rotor 40 and the pump housing 11 , which are arranged concentrically. The eccentrically arranged gear 60 and the non-rotationally symmetrical axial passage 13 as well as those in the axial passage 13 arranged spindle screw 12 and spindle 14 break the rotational symmetry of the device 1 .

Reference symbol list

1

contraption

2nd

first axis of rotation

3rd

second axis of rotation

4th

third axis of rotation

10th

Screw pump

11

Pump housing

12

Spindle screw

13

axial passage

14

Spindle

15

External teeth

20th

Electric motor

30th

stator

31

Stator housing

32

Coil winding

33

Inflow opening

34

Drain opening

35

Flow channel

40

rotor

41

Permanent magnet

42

Internal teeth

50

roller bearing

60

gear

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 10235078 A1 [0003]
• DE 4300512 B4 [0005]
• DE 19949082 B4 [0006]

Claims (10)

Device (1) for conveying a cooling fluid, with a screw pump (10), which has a pump housing (11) and a spindle screw (12) rotatably mounted about a first axis of rotation (2) and arranged in an axial passage (13) of the pump housing (11) ), and with an electric motor (20) for driving the spindle screw (12), which comprises a stator (30) connected in a rotationally fixed manner to the pump housing (11) and a rotor (40) rotationally coupled to the spindle screw (12) the pump housing (11) is rotatably mounted about a second axis of rotation (3) parallel to and spaced from the first axis of rotation (2) and is axially penetrated by the spindle screw (12). Device after Claim 1 , wherein the screw pump (10) comprises a running spindle (14) which is arranged in the pump housing (11) and is rotatable about a third axis of rotation (4) which is parallel to and spaced from the first axis of rotation (2) and the second axis of rotation (3), which is in engagement with the spindle screw (12). Device according to one of the Claims 1 or 2nd , in which the pump housing (11) has a cylindrical shape and the rotor (40) is designed as a hollow cylinder, and which comprises a roller bearing (50) by means of which the rotor (40) of the electric motor (20) on a peripheral surface of the pump housing ( 11) is stored. Device according to one of the Claims 1 to 3rd , in which the stator (30) comprises a stator housing (31) within which the pump housing (11) is arranged and which has an inflow opening (33), an outflow opening (34) and an inflow opening (33) with the outflow opening (34) connecting flow channel (35) for a cooling fluid, which extends through the axial passage (13) of the pump housing (11). Device after Claim 4 , in which a cross-sectional area of the inflow opening (33) and a cross-sectional area of the outflow opening (34) are circular, have an identical surface area and are centered with respect to the second axis of rotation (3). Device after Claim 5 , in which an axial projection of a cross-sectional area of the axial passage (13) of the pump housing (11) into a plane of the cross-sectional area of the inflow opening (33) or the outflow opening (34) completely in the cross-sectional area of the inflow opening (33) or the outflow opening (34) is included. Device after Claim 6 which comprises a gearwheel (60) rotatably mounted on the stator housing (31) and / or on the pump housing (11) and in which the rotor (40) projects axially beyond the pump housing (11) in the direction of the drain opening (34) and in an edge area facing the drain opening (34) has an internal toothing (42) and the spindle screw (12) has an external toothing (15) at an axial end facing the drain opening (34), each of which meshes with the gear (60). Device after Claim 7 , in which the rotor (40) in the axially protruding edge region has a radially inwardly pointing annular projection on which the internal toothing (42) is formed. Device according to one of the Claims 7 or 8th , wherein the gear (60) is arranged such that an axial projection of the gear (60) into a plane of a cross-sectional area of a drain opening (34) of a stator housing (31) of the stator (30) is arranged outside the cross-sectional area of the drain opening (34) is. Vehicle, with a cooling circuit, which has a device (1) for conveying a cooling fluid according to one of the Claims 1 to 9 includes.

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