EP3779205A1 - Fluid pump with an electrical drive - Google Patents

Abstract

The present invention relates to a fluid pump (1) with an electric drive, in particular a fluid pump (1) for a cooling and/or heating circuit of a motor vehicle, with a stator (5), an axle (7) connected to a pump housing (2) and a rotor (8) arranged on the axle (7), which has an impeller (9) and is mounted on the axle (7) by means of a radially acting first bearing (10), the axle (7), the stator ( 5) and the rotor (8) are arranged in the pump housing (2) and the axle (7) has a radial groove (14) on a free end (15) on the outer circumference. The fluid pump is characterized in that a deformable locking element (13) is arranged in the groove (14) and an axially acting second bearing (12) for the rotor (8) is arranged between the locking element (13) and the rotor (8), the second bearing (12) being designed to introduce an axially acting force (11) generated by the rotor (8) into the axle (7) via the deformable blocking element (13).

Description

The present invention relates to a fluid pump with an electric drive, in particular a fluid pump for a cooling and / or heating circuit of a motor vehicle, with a stator, an axle connected to a pump housing and a rotor arranged on the axle, which has an impeller and a radially acting first bearing is mounted on the axle, the axle, the stator and the rotor being arranged in the pump housing and the axle having a radially circumferential groove at a free end on the outer circumference.

Electrically driven fluid pumps are well known in the prior art. So can be found in the DE 4411960 A1 a detailed description of such a pump. The pump shown there has a bell-shaped rotor, in the cylindrical interior of which the stator engages. A pipe or. The cup-shaped wall runs between the rotor and the stator, an axis about which the rotor is rotatably mounted is let into the bottom of the cup.

Furthermore, from the EP 22 73123 A1 an electric motor vehicle coolant pump for cooling a motor vehicle internal combustion engine is known. This coolant pump has a containment can motor arrangement in which a rotor with the blades and a plain bearing sleeve is mounted on a stationary metallic axle. The pump blades of the rotor are arranged axially in the area of the plain bearing sleeve. At a distal end of the axle, a metallic stop ring is arranged, which is welded to the axle. The welded stop ring is used to axially fix the rotor.

The disadvantage of the known solutions is that the rotor is permanently fixed on the axle during assembly. A subsequent exchange of the rotor or a repair of the bearing is not possible or only with difficulty. In addition, a relatively complex thermal joining process is required during production, which can, for example, be accompanied by an undesirable introduction of heat into the component and weld spatter, and components must be damaged for dismantling.

It is therefore the object of the present invention to at least partially solve the problems arising from the prior art and, in particular, to provide a fluid pump that is easy to manufacture, has better acoustic properties and with Requirement, can be easily repaired and / or can be easily adapted to different operating conditions.

A fluid pump or a production method for a fluid pump according to the independently formulated patent claims contributes to the solution of this object (s). It should be pointed out that the features listed individually in the dependent claims can be combined with one another in any technologically meaningful way and define further embodiments of the invention. In addition, the features specified in the claims are explained and specified in more detail in the description, with further preferred exemplary embodiments of the invention being presented.

A fluid pump with an electric drive, in particular a fluid pump for a cooling and / or heating circuit of a motor vehicle, which has at least one stator, an axle connected to a pump housing and a rotor arranged on the axle, contributes to this. The rotor has an impeller and is mounted on the axle by means of a radially acting first bearing.

The axle, the stator and the rotor are arranged in the pump housing, the axle having a radial groove at a free end on the outer circumference. A deformable locking element is arranged in the groove. Furthermore, an axially acting second bearing for the rotor is arranged between the locking element and the rotor, the second bearing being designed to introduce an axially acting force generated by the rotor into the axle via the deformable locking element.

It was recognized that a second axially acting bearing can be fixed in the axial direction in a particularly advantageous manner by means of a deformable locking element. The deformability in the context of the present invention can optionally be plastic or elastic of the locking element. For this purpose, the deformable locking element is arranged in a groove which extends on the outer circumference of the axle and in its radial direction. The fluid pump designed in this way can be installed in a particularly simple manner by first plugging the rotor together with the first bearing onto the axle during installation. The second bearing is then installed, which prevents the rotor from being pulled off the axle in the axial direction. Finally, in the last step, the second bearing is fixed in the axial direction by simply inserting the deformable locking element into the groove. If you were to use the locking element in want to use radial direction, there would be a collision with the impeller blades or the geometry of the impellers would have to be shortened accordingly. With the present invention, however, in connection with the other mentioned advantages of the invention, a particularly simple axial assembly is made possible.

The axial forces generated by the rotor during pump operation can thus be passed on from the rotor via the bearing or contact point with the second bearing, which is not designed to be deformable, via the contact point of the second bearing with the deformable locking element to the deformable locking element before the deformable locking element that introduces axial forces into the axle via the groove.
In the case of repairs, only the deformable locking element has to be removed in order to be able to dismantle the fluid pump again into its individual components. This enables easy access to the bearing points or, for example, a simple exchange of the rotor or the pump wheel.

In addition, the rotor and the second bearing can be acoustically decoupled from the axle by the deformable locking element, which has a positive effect on the noise generation in the operating state, i.e. it is reduced. In addition, fluid pumps constructed in this way can be varied in a particularly simple manner in the manner of a modular principle and adapted to the respective operating conditions. In this way, individual or all components, such as the housing, pump wheel, rotor or the second bearing, can be manufactured from plastic and used with low loads. Furthermore, these components can be replaced by components made of metal or ceramic, for example, in the event of higher thermal loads. As a result, the most varied variants of the fluid pumps can be represented by means of the modular principle. Last but not least, by avoiding the introduction of heat during the production of the fluid pump, it is possible to use plastics for the components.

The second bearing can have an opening for receiving the axle. In this case, the second bearing can be pushed onto the axle in a particularly simple manner during assembly, the axle then being able to protrude through the opening.

For a particularly reliable transmission of the axial forces, provision can also be made for the opening to have opening cross-sections of different sizes in the axial direction of the axis. The opening cross-sections of the opening in the second bearing of different sizes make it possible for one that acts in the radial direction to the axis Exert force from the second bearing on the deformable locking element. In this way it can be achieved that an axial force introduced into the second bearing is deflected into a radial force and the deformable locking element is pressed in the direction of the groove by means of this radial force. Consequently, the greater the axial force exerted by the rotor via the second bearing, the greater the radial drive force which holds the deformable locking element in the groove. If the opening is also circular, the second bearing can be self-centering on the deformable locking element in the installed state. While, for example, a stop ring welded to the shaft, as is known from the prior art, has the disadvantage that this stop ring does not sit centrally on the axis and is also fixed in a position inclined to the axis due to the uneven heat input of the welding process, the present invention enables self-centering of the second bearing on the deformable locking element. At the same time, the bearing surface of the second bearing is automatically aligned at right angles to the longitudinal axis of the axle.

Furthermore, the deformable locking element can even compensate for positional deviations of the pump wheel, which are caused by tolerances between the first bearing and the pump wheel. For example, if the center axis of the pump wheel is slightly inclined with respect to the axis due to the tolerances, the second bearing can compensate for this inclination via the deformable locking element.

It is particularly advantageous if the opening is designed as a (continuous or) flat transition between two opening cross-sections of different sizes and axially spaced apart from one another.

In a further particularly simple embodiment, for example, a simple stepped bore can be provided which has a larger and a smaller diameter in the axial direction (directly) one behind the other. The different diameters preferably merge into one another as gently as possible via corresponding rounded edges in order not to damage the deformable locking element during assembly and not to generate unnecessarily high material stresses in the contact area with the second bearing in the installed state.

If you now choose the diameter so that the opening cross-sections of the breakthrough become smaller with increasing distance from the free end, the force component exerted by the second bearing in the radial direction on the locking element increases when that second bearing is moved in the direction of the free end. The system can thus be designed to be self-locking or self-locking.

It can further be provided that the opening is designed as a conical bore section. Here, the angle of the cone is between 5 ° and 60 °, preferably between 10 ° and 50 °, based on the longitudinal axis of the axis or based on the center axis of the opening. By means of a cone, the exerted axial force can be deflected particularly effectively into a radial force in order to press the deformable locking element into the groove.

In this way, even larger axial forces can be absorbed without any problems.

The opening can be designed as a conical bore section or as a bore with an integrally formed bevel, wherein the bevel or the cone can preferably extend from an end face of the second bearing to the (smallest) bore section. Such a bevel or such a cone can be produced particularly favorably in terms of production technology and the function corresponds to that of the previously described conical bore section.

For safe and reliable manufacture, it is advantageously provided that the axle has symmetrically designed and / or arranged radial circumferential grooves at its two ends. The axes designed in this way can thus be in both positions, i.e. H. can be fixed in the housing either with the first end or the second end, without causing a manufacturing error. The axles can be pressed, glued, screwed and / or injected into the pump housing. All suitable manufacturing processes known in the prior art are available for this purpose.

In order to improve the durability of the deformable locking element and / or to facilitate assembly, it can also be advantageously provided that the groove has at least partially rounded edges. The rounded edges facilitate the assembly (the at least partial penetration into the groove) of the deformable locking element and prevent damage to the locking element from sharp edges. In this case, all edges of the groove can optionally be rounded or only those with which the deformable locking element comes into contact during assembly or disassembly.

Particularly favorable deformable properties are achieved if the blocking element consists at least partially of an elastomer. Suitable elastomers for use in a heating and / or cooling circuit are, for example, HNBR or EPDM. These can be used advantageously for axes with a diameter of 3-10 mm and especially for axes with a diameter of 6-8 mm.

In other embodiments of the invention, especially with larger axle diameters, locking elements made of spring steel can also be used. Such locking elements can for example be formed from a helically wound wire, the turns of which lie against one another. Such a locking element can be temporarily expanded radially for assembly in the groove of the axle, similar to a ring of a key ring, without it experiencing a plastic deformation.

It is particularly favorable if the locking element consists of an incompressible material. While the invention can already be implemented with compressible and foamed elastomers, provided they have sufficient strength or hardness (e.g. Shore hardness), it is even more favorable if the selected elastomer is incompressible. In this case, the deformable locking element can be moved particularly effectively into the groove by the radial forces exerted by the second bearing and thus ensure a particularly secure hold of the second bearing on the axle.

For fluid pumps with a particularly long service life, a preferred exemplary embodiment of the present invention provides for the second bearing to consist of a ceramic material. The second bearing can thus form a particularly smooth and low-friction contact point with the rotor. In addition to the low coefficient of friction, the contact point also has a particularly high wear resistance. The fluid pump designed in this way is therefore particularly low-wear, energy-saving and durable. When producing the second bearing from a ceramic material, in addition to the low-friction contact point with the rotor, a contact surface that is in contact with the deformable locking element can be designed with increased roughness. The increased surface roughness between the deformable locking element and the second bearing prevents inadvertent rotation of the second bearing relative to the deformable locking element while the fluid pump is in operation. Such a permanent relative movement between the two components would increase in the long term unnecessary wear thus lead to premature wear on one of the components or even on both components. However, this can reliably be prevented.

In a further particularly inexpensive embodiment it is provided that the second bearing consists of a plastic material. Thermosetting plastics and thermoplastics are preferably used as plastic materials. Unreinforced thermosets, reinforced thermoplastics or thermoset-bound graphites can be used particularly advantageously for the present invention. Such plastic materials can be used if, for example, only small axial forces have to be supported.

In another advantageous embodiment, it is provided that the second bearing consists of a metallic material. If the fluid pump is to be used, for example, at very high temperatures, it can be advantageous to manufacture the second bearing from metal. Metals have a higher hardness than plastics, are temperature-resistant and can be processed cheaply into second bearings. This can be done by punching, exciting processes or the sintering of powder metals. Alternatively, the metals can also be processed using a metal injection process, also known as metal injection molding (MIM).

Metallic materials also have a relatively large surface roughness in the untreated state, which prevents unintentional relative movement between the second bearing and the deformable locking element.

For an additional prevention of this relative movement, a rotary brake can advantageously be arranged between the second bearing and the locking element. Such a rotary brake can be formed, for example, by radial webs on the contact surface of the second bearing to the deformable locking element or by targeted formation of burrs or roughness on punched metallic second bearings. In addition to the formation of burrs, there is also the possibility of forming depressions or notches in the metal during punching, which then engage positively in the locking element, which is shaped complementarily to it, and thereby act as a rotary brake. In this way, an unintentional relative movement between the deformable locking element and the second bearing can be reliably avoided.

Furthermore, a method for producing a fluid pump, in particular a liquid pump for a cooling and / or cooling system, contributes to the solution of the stated problem Heating circuit of a motor vehicle, in which the fluid pump has a rotor which has an impeller and which can be rotated about an axis fixedly arranged in terms of rotation. The method is characterized, for example, in that the first end of the axis is fixed in a housing of the pump, the rotor is pushed onto the axis, then the second bearing is pushed onto the axis, and (then or later) the rotor and the second bearing is axially secured by a deformable locking element inserted into a groove in the axle. According to the proposed method, the fluid pump can be installed and also dismantled again in a particularly simple manner, since it is only necessary to remove the deformable locking element in order to be able to dismantle the remaining components of the fluid pump.

The method can be implemented in particular with the fluid pump presented here and vice versa. The explanations of the configurations of the fluid pump or its assembly can also be used here to further specify the method.

Fig.1:

eine schematische Schnittansicht einer erfindungsgemäßen Fluidpumpe;

Fig. 2:

eine Schnittansicht durch ein zweites Lager mit deformierbarem Sperrelement;

Fig. 3a:

eine erste Ausführungsform eines zweiten Lagers;

Fig. 3b:

eine zweite Ausführungsform eines zweiten Lagers; und

Fig. 4:

eine weitere erfindungsgemäße Ausführungsform mit verrundeter Nut.

The invention and the technical environment are explained in more detail below with reference to the figures. It should be pointed out that the figures show particularly preferred embodiment variants of the invention, to which, however, it is not restricted. In the drawing shows:

Fig. 1:

a schematic sectional view of a fluid pump according to the invention;

Fig. 2:

a sectional view through a second bearing with a deformable locking element;

Fig. 3a:

a first embodiment of a second bearing;

Fig. 3b:

a second embodiment of a second bearing; and

Fig. 4:

Another embodiment of the invention with a rounded groove.

In Figure 1 a fluid pump 1 according to the invention is shown in an axial sectional view. The fluid pump 1 comprises a pump housing 2 with an inlet connection 3 and an outlet connection 4. A stator 5 is arranged in the pump housing 2 and is separated from the liquid-carrying area of the fluid pump 1 by a wall or a hood 6. An axle 7 is fixedly mounted in the hood 6. A rotor 8, which is connected to an impeller 9 and is mounted by means of a first bearing 10 in FIG radial direction to the axis 7 is supported and guided. During operation of the fluid pump 1, fluid is sucked in via the inlet connector 3 and deflected in the direction of the outlet connector 4 by the rotating vanes of the impeller 9. The impeller 9 generates an axial force in the direction of the arrow 11. A second bearing 12 is arranged on the axis 7 to absorb the axial force and to support it. The second bearing 12 is disk-shaped and is used for the axial support of the impeller 9 and at the same time for introducing the axial force into the axis 7. For this purpose, a deformable locking element 13 is provided at a free end 15 of the axis 7 in a groove 14. In the embodiment shown, the deformable locking element 13 is designed as an O-ring which is inserted into the upper groove 14 and has a high coefficient of friction with respect to the axis 7 and the second bearing 12. The axis 7 can have a further groove opposite at the mounted end 23, via which the axis 7 is secured in the hood 6, it being possible for the two grooves to be identical.

It can be clearly seen here that the axis 7 is symmetrical and has two circumferential grooves 14 so that incorrectly positioned installation of the axis 7 is not possible.

The Figure 2 shows an enlarged representation of another embodiment according to the invention, in which the axis 7 has a conical or trapezoidal groove 14. In the groove 14, the deformable locking element 13 is used, which is designed as an elastomer O-ring. The impeller 9 exerts an axial force (arrow 11) on the second bearing 12 via the first bearing 10. The second bearing 12 is ring-shaped and has a cylindrical bore section 16, a conical bore section 17 and an upper edge 18. The cylindrical bore section 16 and the conical bore section 17 form an opening 19 through which the axis 7 protrudes. If the second bearing 12 is now moved in the direction of the arrow 11 due to the axial force, the conical bore section 17 first comes into contact with the deformable locking element 13.

When this contact state is reached, the axial force is deflected via the conical bore section 17 in a radial direction acting at right angles thereto and presses the deformable locking element 13 into the groove 14 with increasing movement of the second bearing 12 in the direction of arrow 11 in the radial direction the axial force, the greater the holding force of the locking element 13 pressed into the groove 14. Since the deformable locking element 13 is designed as an incompressible O-ring, and If the cross-sectional area of the O-ring is larger than that of the associated groove 14, the O-ring always protrudes beyond the groove 14 in the installed state, via which the axial forces of the impeller 9 can be introduced into the axle 7.

In Figure 3a Another embodiment of the invention of a second bearing 12 is shown in a partial axial sectional view. The second bearing 12 is in turn annular with an opening 19 and encloses the axis 7. Between the axis 7 and the second bearing 12, a deformable locking element 13 is pressed by the second bearing 12 in the radial direction 20 into the groove 14. In this embodiment, the opening 19 is designed as a conical bore section 16. The cone used is open at an angle 22 in the direction of the free end 15. This means that an opening cross section of the opening 19 in the area of the upper edge 18 is larger than the opening cross section of the opening 19 in the area of a lower edge 21. The opening cross section is viewed in a plane whose normal direction is aligned parallel to the longitudinal axis of the axis 7. In order to make assembly as simple as possible, the opening 19 in the area of the lower edge 21 can be slightly oversized relative to the axis 7. This excess makes it easier to attach the second bearing to the axle 7 and can be compensated for by compensating for tolerances of the deformable locking element 13.

The Figure 3b shows a further embodiment in which the second bearing 12 has an opening 19 which is designed as a cylindrical bore section 16 in the lower region. However, this cylindrical bore section 16 ends before it reaches the upper edge 18, whereby a free-form, flat, for example dome-shaped transition is provided to overcome a diameter jump from the smaller diameter in the area of the lower edge 21 to the larger diameter in the area of the upper edge 18, which is contoured so that the locking element 13 is tightly enclosed by the latter and is pressed into the groove 14 with increasing movement of the second bearing 12 in the direction of the arrow 11.

After all, in Figure 4 Another embodiment is shown in which the groove 14 has rounded edges. The edges are rounded with a radius R, so that the locking element 13 can be installed or removed easily and without damage.

List of reference symbols

1

Fluid pump

2

Pump housing

3

Inlet connection

4th

Drain connection

5

stator

6

Hood

7th

axis

8th

rotor

9

Impeller

10

first camp

11

arrow

12th

second camp

13

Locking element

14th

Groove

15th

free end

16

cylindrical bore section

17th

conical bore section

18th

Top edge

19th

breakthrough

20th

radial direction

21st

Lower edge

22nd

angle

23

mounted end

R.

radius

Claims (11)

Fluid pump (1) with an electric drive, in particular a fluid pump (1) for a cooling and / or heating circuit of a motor vehicle, with a stator (5), an axle (7) connected to a pump housing (2) and one on the axle (7) arranged rotor (8) which has an impeller (9) and is mounted on the axis (7) by means of a radially acting first bearing (10), the axis (7), the stator (5) and the rotor (8) are arranged in the pump housing (2) and the axis (7) has a circumferential groove (14) at a free end (15), a deformable blocking element (13) in the groove (14) and between the blocking element (13 ) and the rotor (8) an axially acting second bearing (12) for the rotor (8) is arranged, and the second bearing (12) is designed to transmit an axially acting force (11) generated by the rotor (8) to introduce the deformable locking element (13) into the axis (7). Fluid pump (1) according to claim 1, wherein the second bearing (12) has an opening (19) for receiving the non-rotatable axis (7) and the opening (19) over its course along the axial direction of the axis (7) has different opening cross-sections having. Fluid pump (1) according to Claim 2, the opening cross-sections of the opening (19) becoming smaller as the distance from the free end (15) increases. Fluid pump (1) according to one of Claims 2 or 3, the opening being designed as a conical bore section (16). Fluid pump (1) according to one of the preceding claims, wherein the blocking element (13) consists at least partially of an elastomer. Fluid pump (1) according to one of the preceding claims, wherein the blocking element (13) consists of an incompressible material. Fluid pump (1) according to one of the preceding claims, wherein the second bearing (12) consists of a ceramic material. Fluid pump (1) according to one of the preceding claims, wherein the second bearing (12) consists of a plastic material. Fluid pump (1) according to one of the preceding claims, wherein the second bearing (12) consists of a metallic material. Fluid pump (1) according to one of the preceding claims, wherein a rotary brake is arranged between the second bearing (12) and the locking element (13). Method for manufacturing a fluid pump (1), wherein the fluid pump (1) has a rotor which has an impeller and which can be rotated about an axis fixedly arranged in terms of rotation, the first end of the axis being fixed in a housing of the pump, the rotor (8 ) is pushed onto the axle, then the second bearing is pushed onto the axle, and then the rotor (8) and the second bearing are axially secured by a deformable locking element inserted into a groove in the axle.

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