EP2348219A1 - Coolant pump system - Google Patents

Abstract

The assembly has a centrifugal pump (4) surrounded by a tubular container (18). An axial end of the container is sealingly connected to a motor housing of a drive motor (2) e.g. canned motor and electric drive motor. Another axial end (20) of the container is connected to the former axial end in a closed manner. The container comprises a closed wall and suction and pressure openings (24, 26) that extend away from the container in a radial direction. The openings are provided with connection flanges (30). The openings are directly welded to a connection line.

Description

The invention relates to a refrigerant pump unit, according to the preamble of claim 1.

Refrigerant pump units are used to deliver refrigerants or refrigerants to their circulation in refrigeration or air conditioning systems. Centrifugal pumps can be used for this purpose.

The refrigerant is usually in such systems under high pressure, so that high demands are placed on the seals of the individual components and joints. In addition, refrigerants are often expensive, toxic and / or environmentally harmful media, so leakages should be avoided at all costs.

In view of this problem, it is an object of the invention to provide a refrigerant pump unit, in which leaks can be reliably prevented.

This object is achieved by a refrigerant pump unit having the features specified in claim 1. Preferred embodiments will become apparent from the subclaims, the following description and the accompanying figures.

The refrigerant pump unit according to the invention comprises a drive motor, in particular an electric drive motor and a centrifugal pump driven by this. The centrifugal pump can do this be formed one or more stages. Drive motor and centrifugal pump are connected together to form a pump unit.

According to the invention, it is provided that the centrifugal pump is surrounded by a tubular container. This tubular container surrounds the centrifugal pump as an additional wall, preferably radially spaced from the first housing walls of the individual pump stages of the centrifugal pump. The tubular container is sealingly connected to the housing of the drive motor with a first axial end, on which it is formed open. At its opposite axial end of the tubular container is formed closed, so that it has a total of a cup-shaped shape. The container closes the entire system to the outside and absorbs the forces generated by the system pressure of the fluid in its interior. For sealing only a single seal in the interface to the motor housing is required. In this respect, the risk of leaks is reduced by reducing the interfaces to be sealed. In addition, the housing parts of the individual pump stages of the centrifugal pump must not be formed so resistant to pressure that they can absorb the system pressure, these housing parts need only withstand the differential pressure which is generated by the centrifugal pump or its individual pump stages. In this respect, can be dispensed with expensive castings in this area. Since the entire container surrounding the centrifugal pump is preferably filled with the refrigerant to be delivered, the system pressure then prevails both inside and outside the housing of the pump stages of the centrifugal pump assembly. In addition, no higher demands on the seals inside the centrifugal pump must be made because they do not have to hermetically seal the centrifugal pump out to the environment. This function is carried out by the surrounding container.

The tubular container preferably has a suction and pressure connection. In addition to the open axial end, which is connected to the motor housing, these two openings are preferably the only other openings in the container, so that the container is relatively easy to seal outward in this case at only three interfaces. However, it is also conceivable that, depending on the system in which the container is to be installed, it may also be possible to provide more than one suction connection and / or more than one pressure connection to the container. Inside the container, the suction port is connected to the suction side of the centrifugal pump and the pressure port to the pressure side of the centrifugal pump.

Preferably, the suction port and / or pressure port extending in the radial direction away from the container, they thus form connecting pieces for connection to subsequent lines.

Incidentally, the container preferably has a closed wall. Preferably, the wall is formed in one piece or in one piece, optionally by welding a plurality of components. The closed container thus formed has, in addition to the open end face for connecting the motor and the suction and pressure ports thus preferably no further openings or interfaces to be sealed, whereby the risk of leakage is minimized.

The suction connection and / or the pressure connection can be provided with connecting flanges for connection to adjacent pipelines. Alternatively, the suction connection and / or the pressure connection can be designed for direct welding to connection lines. If subsequent lines are welded directly to the suction connection and / or the pressure connection, this has the advantage that no additional seals must be provided at these connections, whereby the risk of leakage is further minimized. In In the event that connection lines are welded directly to the suction port and pressure port, so ideally remains only one opening to be sealed to the container, namely the interface to the drive motor. The suction port and the pressure port may be formed as a connecting piece. Alternatively, the connection lines can also be welded directly to the peripheral wall of the container.

More preferably, the container has in its interior an annular partition, which separates the suction and the pressure side of the centrifugal pump from each other. This annular partition preferably extends as an annular projection of the inner wall radially inwardly. The annular partition wall is seen in the axial direction of the container, that is arranged in the direction of the axis of rotation of the centrifugal pump, preferably between the suction port and the pressure port in the container. On its inner circumference, the annular partition wall is further preferably designed such that it comes into sealing contact with the outer circumference of a housing part of the centrifugal pump arranged in the interior of the container. Here, if appropriate, a seal, for example an O-ring may be provided. In this case, the partition wall in the axial direction is preferably placed so that the centrifugal pump engages with its suction-side axial end in the inner periphery of the partition wall and sealingly abuts the partition wall with the suction-side axial end. At the suction wall side facing away from the partition of the free space between the centrifugal pump and the surrounding container is preferably filled with the exiting from the centrifugal pumps fluid. This space is then preferably connected to the pressure port. Thus, a free space between the centrifugal pump and the inner circumference of the container preferably remains, ie the container has an inner diameter which is larger than the outer diameter of the centrifugal pump.

The centrifugal pump preferably extends concentrically to the container and is in the axial direction, d. H. inserted in the direction of the longitudinal or rotational axis of the centrifugal pump from the open end side into the container. In this case, the container is preferably releasably connected to the motor housing of the drive motor, for example by a bolted flange connection. This allows the container and the motor housing to be separated from one another, in which case the drive motor with the centrifugal pump assembly can be removed from or withdrawn from the container, for example to service or replace the centrifugal pump or the drive motor. In this respect, a very simple maintenance and possibly repair is possible because all connecting lines for connecting the centrifugal pump assembly with other parts of a refrigeration system need not be solved, but can remain firmly connected to the container.

More preferably, the drive motor is designed as a canned motor. That is, the drive motor is a wet-running electric motor. In this case, the split tube is more preferably arranged so that it is sealed directly to the open axial end of the container or is tightly connected to a flange for connection of the drive motor with the container. For example, the split tube can be welded to such a flange on the drive motor or motor housing. This has the advantage that even in the drive motor no further seals for sealing the filled with refrigerant and under system pressure interior are required. Ideally, therefore, only the only seal between the motor housing or drive motor on the one hand and the container on the other side is required. In particular, in the embodiment as a canned motor no shaft seals are required, which are particularly vulnerable to leakage.

As described above, the container is preferably formed pressure-resistant for the system pressure of the zufördernden refrigerant. The container is therefore particularly preferably designed such that it withstands a system pressure> 25, more preferably> 30 and in particular> 50 or 60 bar internal pressure.

The pump unit has in a known manner at least one impeller and a thrust bearing, which receives the axial reaction forces generated by the impeller in operation. This thrust bearing can be arranged for example on a shaft driving the impeller. The thrust bearing consists of a rotating and a fixed bearing part, wherein in operation the axial forces are transmitted from the rotating bearing part to the fixed bearing part and the fixed bearing part in turn is supported for example on the housing of the pump or the drive motor.

According to a preferred embodiment, both the rotating and the stationary bearing part are self-aligning. That is, fixed and rotating bearing part are formed so that their bearing surfaces can align with each other so that they extend parallel to each other and, for example, can come into contact directly with each other to slide in the manner of a sliding bearing on each other. The fact that both the rotating and the fixed bearing part and not only one of the bearing parts is self-aligning, even with position errors or deflections of the shaft reliable storage is possible because the bearing surfaces of the two bearing parts can always assume a mutually parallel angular position in which they slide reliably on each other. A tumbling of one of the bearing parts is prevented.

Such a thrust bearing is preferably suitable for an arrangement in the middle of the shaft. Thus, the thrust bearing on a drive shaft is preferred spaced from the axial ends of the drive shaft, in particular, it is located closer to the axial center of the drive shaft than towards the axial ends. That is, in this embodiment, the thrust bearing is in the region of the drive shaft, in which there may be slight radial deflections of the shaft and positional errors of the shaft, more than at the axial ends, where the shaft is usually mounted radially. The arrangement of the thrust bearing in this area usually has the problem that the bearing parts start to wobble, which causes increased friction and increased wear. Due to the self-aligning design of the two bearing parts according to the invention, this is avoided and even with an arrangement of the axial bearing in this central region of the shaft ensures a smooth and low-wear running.

On the drive shaft, a rotor of an electric drive motor and at least one impeller is preferably arranged, wherein the thrust bearing is located in the axial direction between the rotor and the at least one impeller. In this case, the drive shaft may be formed as a continuous, one-piece drive shaft, but also in several parts, for example in the form of a motor shaft and a pump shaft to be formed, which are rotatably connected to each other. The axial bearing is thus preferably arranged on the axial end of the centrifugal pump facing the drive motor.

More preferably, the thrust bearing is arranged on the pressure side of the at least one impeller or an arrangement of a plurality of impellers, in the case of a multi-stage centrifugal pump. The pressure side is that side of the impeller on which the medium to be delivered has a higher pressure. That is to say that the axial bearing is preferably arranged in the region of the pump in which the highest fluid pressure prevails. This has the advantage that sufficient lubrication of the axial bearing can be ensured by the fluid in this area. This is especially true in the promotion of fluids or liquids which tend to evaporate upon heating and / or lower pressure. By arranging in the region of the highest pressure, it is ensured that in this area the fluid to be delivered is present in the liquid state of aggregation and can thus ensure adequate lubrication of the axial bearing. This is particularly important if the fluid to be delivered is, for example, a refrigerant which evaporates already at lower temperatures. The region of the highest pressure of the centrifugal pump is preferably located on the axial end of the centrifugal pump facing the drive motor. That is, the suction side of the pump is spaced in the axial direction of the drive motor. The thrust bearing is preferably located in front of the drive motor, so that the fluid to be delivered in this area is not heated by the waste heat of the drive motor substantially. Ideally, the thrust bearing is thus in a range of high pressure and low temperature of the fluid to be delivered, so that it is ensured in this area that the fluid can not evaporate and lubricate the bearing in liquid form.

As described above, the thrust bearing is preferably designed as a plain bearing and is lubricated by the fluid to be delivered or the liquid to be delivered.

More preferably, a bearing surface of at least one bearing part for alignment in its angular position to the axis of rotation of the drive shaft in at least a limited angular range is free to pivot. As a result, the self-alignment is ensured, ie the bearing surface can pivot in its angular position with respect to the axis of rotation and align at an angle so that it comes flush against the opposite bearing surface of the other bearing part. Thus, tumbling during operation can be prevented.

For this purpose, more preferably, the bearing surface of at least one bearing part for alignment in its angular position about two mutually perpendicular and perpendicular to the axis of rotation of the drive shaft extending axes pivotally. That is, this essentially represents a pivoting on a spherical plane whose center lies on the axis of rotation. Thus, the bearing surface can align freely in all directions in their angular position.

Preferably, the bearing surface of at least one bearing part is attached or supported on a carrier which has a bearing surface facing away from the spherical contact surface, which bears slidably on a corresponding conical counter-contact surface. In this case, the spherical contact surface is preferably convexly curved and the conical counter-contact surface is correspondingly concave. In this case, the counter-bearing surface is preferably curved concavely in the same radius, that is to say spherically formed, so that the surfaces come into contact with one another flatly. Contact surface and counter-contact surface thus form parts of a spherical surface and allow the above-described pivoting of the bearing surface in its angular position relative to the axis of rotation. The conical counter-bearing surface does not necessarily have to be spherical, instead it could also be conical with a straight cross-sectional line, the diameter and pitch of the cone being selected such that the spherical bearing surface can come into abutment against the conical counter-bearing surface at least in a line. The bearing surface can be formed directly on the carrier, that is, the carrier itself is formed from the desired bearing material. Alternatively, it is possible to provide the carrier as a separate component to which at least one bearing element made of a suitable bearing material are arranged, on which the actual bearing surface is formed.

More preferably, the contact surface and the counter-contact surface of at least one bearing part, preferably the rotating bearing part held by spring force in plant. This has the advantage that, even when the pump is at a standstill, the angular position of the bearing surface occupied by relative pivoting of contact surface and opposing contact surface can be maintained, since contact surface and counter-contact surface are held in contact with a certain frictional engagement.

Further, engagement elements are expediently arranged on the contact surface and the counter-contact surface, which are engaged with each other for torque transmission. The contact surface and the counter-contact surface should slide against each other to change the angular position of the bearing surface. As described above, this essentially involves pivoting about two mutually orthogonal pivot axes which intersect the axis of rotation of the drive shaft. However, pivoting or turning about the axis of rotation between the contact surface and the counter-contact surface is undesirable since this is the movement which is to take place in the axial bearing between the bearing surfaces of the two bearing parts. These should rotate together. In this respect, a rotation between the contact surface and counter-contact surface is to be prevented. The engagement elements may be formed, for example, in the form of engagement projections and corresponding engagement grooves, wherein the engagement projections are formed, for example, on the abutment surface and the engagement grooves in the counter abutment surface. The engagement projections and engagement grooves preferably extend in the radial direction, so that the engagement projections in the engagement grooves can move relative to one another when pivoting the contact surface relative to the counter-contact surface. However, a movement in the circumferential direction relative to each other is prevented. This allows a torque between contact surface and counter-contact surface be ensured by the positive engagement of the engagement elements.

The contact surface and / or the counter contact surface are preferably made of a ceramic material. These materials have sufficient strength and in particular wear resistance.

More preferably, one of the bearing parts on a bearing surface, which is formed by a plurality of individual bearing shoes and the other bearing part has a continuous bearing surface on which slide the bearing shoes. Thus, for example, the stationary or stationary bearing part may have a plurality of individual bearing shoes, while the rotating bearing part has an annular continuous bearing surface, which is preferably made as a one-piece component. However, grooves or recesses in the surface may be provided in the continuous bearing surface in order to ensure the supply of the fluid to be pumped by the pump for lubricating the bearing. The individual bearing shoes on the other bearing part may have a certain mobility, so that they can also align with their O-benflächen relative to the opposite bearing surface, so that the bearing surfaces can come to rest flat against each other. Free spaces or gaps can remain between the individual bearing shoes, which also serve to supply the fluid to be delivered or the fluid to be conveyed for lubricating the bearing. Also, corresponding recesses or grooves for lubricant supply can be provided in the bearing surfaces on the bearing shoes.

As described above, the centrifugal pump unit is configured to convey a refrigerant. Especially in such a centrifugal pump unit, it is desirable to arrange the thrust bearing on the pressure side of the centrifugal pump, ie in the axial center region of the shaft, wherein the quality of the storage is improved by the inventive design of the thrust bearing in the manner described above.

Figur 1 -

eine Schnittansicht eines Kreiselpumpenaggregates für die Förderung eines Kältemittels gemäß einer ersten Ausführungsform,

Figur 2 -

eine Schnittansicht eines Kreiselpumpenaggregates für die Förderung eines Kältemittels gemäß einer zweiten Ausführungsform,

Figur 3 -

eine perspektivische Gesamtansicht des Kreisel- pumpenaggregates gemäß Figur 1,

Figur 4 -

in einer perspektivischen Ansicht das Kreiselpum- penaggregat gemäß Figur 3 im geöffneten Zu - stand,

Figur 5 -

vergrößert die Ausgestaltung des Axiallagers in den Kreiselpumpen gemäß den Figuren 1 und 2,

Figur 6 -

in einer perspektivischen Explosionsansicht den ers- ten rotierenden Lagerteil des Axiallagers gemäß Figur 5,

Figur 7 -

eine perspektivische Explosionsansicht des festste- henden Lagerteils gemäß Figur 6 in anderer axialer Richtung gesehen,

Figur 8 -

eine perspektivische Explosionsansicht des festste- henden Lagerteils des Axiallagers gemäß Figur 5 und

Figur 9 -

eine perspektivische Explosionsansicht des festste- henden Lagerteils gemäß Figur 8 in anderer axialer Richtung gesehen.

The invention will now be described by way of example with reference to the accompanying drawings. In these shows:

FIG. 1 -

FIG. 2 a sectional view of a centrifugal pump assembly for conveying a refrigerant according to a first embodiment, FIG.

FIG. 2 -

FIG. 2 is a sectional view of a centrifugal pump assembly for conveying a refrigerant according to a second embodiment; FIG.

FIG. 3 -

an overall perspective view of the centrifugal pump assembly according to FIG. 1 .

FIG. 4 -

in a perspective view of the Kreiselpum- pagaggregat according to FIG. 3 in the open state,

FIG. 5 -

increases the configuration of the thrust bearing in the centrifugal pumps according to the FIGS. 1 and 2 .

FIG. 6 -

in a perspective exploded view of the first rotating bearing part of the thrust bearing according to FIG. 5 .

FIG. 7 -

an exploded perspective view of the fixed bearing part according to FIG. 6 seen in another axial direction,

FIG. 8 -

an exploded perspective view of the festste- Henden bearing part of the thrust bearing according to FIG. 5 and

FIG. 9

an exploded perspective view of the fixed bearing part according to FIG. 8 seen in another axial direction.

The in the FIGS. 1 and 2 shown centrifugal pump units are specially designed for the promotion of refrigerants and have at an axial end to a drive motor 2, on which the axial side, ie in the direction of the axis of rotation X, a centrifugal pump 4 is attached. The centrifugal pump 4 is designed in multiple stages, that is, it has a plurality of in the axial direction one behind the other on the drive shaft 6 arranged impellers 8. The wheels 8 are as known from conventional centrifugal pumps ago surrounded by housing parts 10 with internal nozzles 12. The nozzles 12 are used to guide the flow of an impeller 8 to the next and for deflecting the radially emerging from the impeller 8 flow in the axial direction.

The housing parts 10 are placed in the axial direction X together, so that they together form a tubular housing. At the first axial end 13 of the centrifugal pump 4, which forms the suction side, a filter 14 is arranged, through which the refrigerant to be delivered is sucked by the centrifugal pump 4 and enters into this. At the opposite pressure-side axial end, circumferential outlet openings 16 are arranged in the last housing part 10, through which the refrigerant conveyed by the centrifugal pump 4 exits radially out of the centrifugal pump 4.

In the promotion of refrigerants, the problem is that this is usually funded under a high system pressure. The total system pressure of a refrigeration system can be more than 50 bar, while the differential pressure between the suction and pressure side of the centrifugal pump 4 can be much lower, for example, in the range between 2.5 and 6 bar. The high system pressure, however, requires that the centrifugal pump assembly be sufficiently pressure-resistant. In particular, in the promotion of refrigerants leaks are to be avoided at all costs, since such refrigerants are often expensive, harmful to the environment and / or toxic, so that their escape into the environment must be avoided.

In order to make the centrifugal pump assembly sufficiently leakproof and pressure-resistant, the centrifugal pump 4 is arranged in a surrounding pressure-resistant container 18. The container 18 is tubular and closed at its end remote from the drive motor 2 end 20. Thus, a cup-shaped container shape is achieved overall. The container has only three openings. These are an opening 22, which is formed by the end face of the container 18 facing away from the axial end 20, as well as a suction opening 24 and a pressure opening 26. Incidentally, the container wall is formed completely closed. The container 18 may in particular be pressure-tight welded in the other areas. Through the suction port 24, the refrigerant to be delivered is sucked and then enters through the filter 14 in the centrifugal pump 4 a. The conveyed by the stages of the centrifugal pump refrigerant then exits at the opposite axial end of the centrifugal pump 4 through the outlet openings 16. It then flows through the gap 28 between the outside of the housing parts 10 and the inner circumference of the container 18 to the pressure port 26, through which it then exits the centrifugal pump assembly. To form the gap 28, the inner diameter of the container 18, which is preferably a circular Cross-section with respect to the axis of rotation X, formed larger than the outer diameter of the housing parts 10th

Inside the container 18, a ring 29 is arranged on the inner wall, which forms a partition wall in the gap 28 and separates the pressure side of the suction side. The ring 29 sealingly abuts the axial end 13 of the tubular housing formed from the housing parts 10. For this purpose, an O-ring is provided to the seal. This prevents the fluid from flowing from the pressure side in the gap 28 into the suction side and the opening at the axial end 13 of the centrifugal pump 4. The ring 29 is fixedly and tightly connected to the container wall, in particular welded.

At the in FIG. 1 As shown, the suction opening 24 and the pressure opening 26 are surrounded by flanges 30, by means of which the centrifugal pump unit can be connected to adjacent connecting lines. In this case, between the flanges 30 and against these mating connection flanges (not shown here) is interposed in each case a sealing element for sealing. In order to avoid such a seal, it is also possible to weld the container 18 directly with subsequent pipes. For this purpose, the embodiment according to FIG. 2 provided in which the suction port 24 and the pressure port 26 are formed only by radially extending away from the container 18 tubular nozzle 32, which can be welded directly to adjoining lines. Alternatively, it would also be possible to weld subsequent lines directly to the container 18. In this way, sealed connection points are avoided, which form a potential risk of leakage.

Surrounding the opening 20, a flange 34 is disposed at the axial end of the container 18, which is circumferentially with the wall of the container 18 is welded. This flange 34 serves to connect to the drive motor 2, which for this purpose at its the centrifugal pump 4 facing axial end has a counter flange 36 which is screwed by means of screws 38 to the flange 34. Between flange 34 and mating flange 36, an O-ring 40 is arranged for sealing.

The drive motor 2 is designed as a canned motor, wherein its split tube 42 is connected at its open the centrifugal pump 4 end facing sealingly with the mating flange 36, preferably welded thereto. By this configuration it is achieved that the entire centrifugal pump assembly except the suction ports 24 and 26 only has an interface at which the interior is to be sealed to the outside, namely between the flange 34 and the counter flange 36 in the region of the connection between the drive motor 2 and container 18th In the case that also the suction ports 24 and 26 as in the embodiment according to FIG. 2 are connected by welding with subsequent pipes, so only a single seal for sealing the pressure chamber is required to the outside. This minimizes the risk of leakage. In addition, it is very easy for maintenance purposes, the entire centrifugal pump 4, as in FIG. 4 shown in the axial direction X after removing the screws 38 to remove from the container 18. Thus, the entire centrifugal pump 4 including the drive motor 2 can be replaced very easily.

A further feature of the centrifugal pump unit according to the invention is the configuration of the axial bearing 44, which is described below with reference to FIG FIGS. 5 to 9 will be described in detail.

As in FIG. 1 and 2 can be seen, the thrust bearing 44 is disposed in the central region of the drive shaft 6, that is, it is from the two axial ends the drive shaft 6 spaced and located closer to the axial center of the drive shaft 6 as to the axial ends. The thrust bearing 44 thus lies between the centrifugal pump 4 and the rotor 46 of the drive motor 2, which is also mounted on the drive shaft 6. In the example shown here, the drive shaft 6 is formed in two parts, the part of the shaft in the rotor 2 is separated from the part of the drive shaft 6 in the centrifugal pump 4. Both parts are non-rotatably connected. However, it should be understood that here also a one-piece drive shaft 6 could find use.

The position of the thrust bearing 44 on the drive motor 2 facing the end of the centrifugal pump 4 has the advantage that the thrust bearing 44, which is lubricated by the delivered refrigerant, located in the region of the centrifugal pump, in which the highest pressure of the refrigerant prevails. At the same time, however, the axial bearing is still spaced from the rotor 46 of the drive motor 2, so that in this area the delivered refrigerant is not heated excessively by the waste heat of the drive motor 2. This means that the axial bearing 44 is located precisely in the region in which the refrigerant does not evaporate due to the high pressure and the not yet completed heating by the drive motor, so that reliable fluid lubrication of the axial bearing 44 is ensured here.

In the central region of the drive shaft 6, in which the thrust bearing 44 is arranged, there is usually the problem that the parts of a thrust bearing tend to wobble due to possible radial deflections of the drive shaft. According to the invention, this is avoided in that the thrust bearing is self-aligning. The thrust bearing consists of two bearing parts 48 and 50, namely a stationary bearing part 48 and a rotating bearing part 50. The rotating bearing part 50 is rotatably connected to the shaft 6, while the stationary bearing member 48 rotatably in a bolted to the mating flange 36 Housing part 52 is located. Both the stationary bearing part 48 and the rotating bearing part 50 are self-aligning.

The rotating bearing part 50 has an annular bearing element 54 made of a suitable bearing material, for example a ceramic material. On the bearing element 54, a first bearing surface 56 is formed on an axial side with respect to the axis of rotation X. The bearing member 54 is held on a support 58, being centered over an O-ring 60. The O-ring 60 is arranged circumferentially of a projection 62 of the carrier 58, which engages in the inner circumference of the annular bearing element 54, so that the O-ring 60 comes to rest on the inner circumference of the bearing element 54. With the bearing surface 56 facing away from the axial rear side of the bearing element 54 is flat against the support 58 at. The carrier 58 is supported via a wave-shaped spring washer 64 on a radially projecting shoulder 65 of a sleeve 66, wherein the sleeve 66 is fixed to the drive shaft 6.

The bearing element 54 facing away from the rear surface of the support 58 is formed as a spherical contact surface 68. That is, the abutment surface 68 has the shape of an annular spherical portion, with the center of this sphere lying on the axis of rotation X. The contact surface 68 bears against a conical, in this case correspondingly spherically shaped, counter-bearing surface 70, which is formed in a support body 72. The counter-abutment surface 70 in this case has the same curvature, ie, the same radius as the abutment surface 68. The contact surface 68 is convex and the counter-contact surface 70 is concave. The support body 42 in turn is supported on an annular projection 74 on the drive shaft 6. In the example shown here, the projection 74 is formed by the axial end of the shaft portion of the drive shaft 6, which forms the rotor shaft of the rotor 46. In this case, the projection 74 of the shoulder 65 is opposite. and the carrier 58 are clamped by the spring action of the spring washer 64 between the shoulder 65 and the projection 74 and the abutment surface 68 and the counter-abutment surface 70 are held in abutment by this spring force.

Due to the spherical shape of the abutment surface 78 and the counter-abutment surface 70, the carrier X is possible to pivot around the center of the spherical shape of the abutment surface 68 and the counter-abutment surface 70, so that the angular position of the bearing surface 56 with respect to the rotation axis X by two mutually orthogonal and the axis of rotation X orthogonal axes is changeable. In this way, the bearing surface 56 can align itself automatically in its angular position to the axis of rotation X, wherein the contact surface 68 slides on the counter-bearing surface 70. By the spring action of the spring washer 64 ensures that even when the pump is stopped, when the axial force which acts on the thrust bearing in operation, is no longer present, the contact surface 68 and the counter-contact surface 70 are fixed to each other, so that a previously automatically set angular position of the bearing surface 56 is maintained even when the pump is stopped.

Also, the stationary bearing part 48 is formed selbstausrichtend. The stationary bearing part 48 has a plurality of bearing shoes 76, whose axial surfaces form second bearing surfaces 78, which are in sliding contact with the first bearing surface 56. The bearing shoes 76 are fixed in a retaining ring 80, which has recesses 82 which correspond to the outer contour of the bearing shoes 76. Thus, the bearing shoes 76 may extend through the recesses 82 and be fixed in the radial and circumferential direction in the retaining ring 80. At the axial side facing away from the bearing surfaces 78, the bearing shoes 76 rest against a carrier 84. The carrier 84 has on its side facing away from the bearing shoes 76 axial side on a spherical contact surface 86. This spherical contact surface 86 forms an annular surface 86 on. This spherical abutment surface 86 forms an annular section of a spherical surface, wherein the center of the ball is located on the axis of rotation X. The contact surface 86 bears against a counter-contact surface 88, which is formed in the housing part 52. The counter-bearing surface 88 is conical, in this case correspondingly spherical, ie it has the same radius of curvature and is curved around the same center point as the abutment surface 86. The abutment surface 86 is convexly curved, while the counter-abutment surface 88 is concavely curved. This embodiment allows the carrier 84 to pivot about the midpoint of the spherical surface defining the abutment surface 86 and abutment surface 88. Thus, it is possible that the bearing surfaces 78 on the bearing shoes 76 in its angular position automatically align with respect to the axis of rotation X. That is, the bearing surfaces 78 are free to pivot about two mutually orthogonal pivot axes, which extend normal to the longitudinal axis X, in a certain angular range. In this way, the bearing surfaces 78 can always create a flat against the bearing surface 56 of the rotating bearing part, so that there is always a sliding contact without wobbling movement of the bearing surfaces.

In the contact surface 86 are, as in FIG. 9 can be seen, three evenly distributed over the circumference radially extending grooves 90 formed, which improve the fluid circulation and thus the lubrication in the thrust bearing.

In order to hold the carrier 86 rotatably on the housing part 52, on the outer circumference of the contact surface 86, three, uniformly distributed over the circumference, extending in the axial direction engaging projections 92 are formed, which engage in corresponding recesses 94 in the housing part 52. In this case, between the engagement projections 92 and the recesses 94 in particular in radial Rich alignment movement between contact surface 86 and the counter-contact surface 88 remains possible.

Accordingly, the carrier 58 is rotatably mounted on the support body 72, so that a torque from the support body 72 can be transferred to the carrier 58. For this purpose, radially extending engagement projections 96 are arranged on the outer circumference of the contact surface 68, which engage in corresponding recesses 98 in the support body 72. Again, sufficient clearance, in particular in the radial direction between the engagement projections 96 and provided in the recesses 98 in order to keep the pivotal movement of the abutment surface 68 relative to the counter abutment surface 70 further possible.

The contact surfaces 68 and 86 and the counter-bearing surfaces 70 and 88 are preferably made of a hard wear-resistant material, in particular, the carrier 58 may be the housing part 52 and the support body 72 made of a corresponding hard material such as cemented carbide or ceramic.

LIST OF REFERENCE NUMBERS

2 - drive motor 4 - rotary pump 6 - drive shaft 8th - impellers 10 - housing parts 12 - nozzles 13 - axial 14 - filter 16 - outlet openings 18 - container 20 - axial end 22 - opening 24 - suction opening 26 - pressure opening 28 - gap 29 - ring 30 - flanges 32 - Support 34 - flange 36 - companion flange 38 - screw 40 - O-ring 42 - canned 44 - thrust 46 - rotor 48 - stationary bearing part 50 - rotating bearing part 52 - housing part 54 - bearing element 56 - storage area 58 - carrier 60 - O-ring 62 - head Start 64 - spring washer 65 - shoulder 66 - shell 68 - contact surface 70 - Anvil surface 72 - support body 74 - head Start 76 - stock shoes 78 - storage areas 80 - retaining ring 82 - recesses 84 - carrier 86 - contact surface 88 - Anvil surface 90 - groove 92 - engagement projections 94 - recesses 96 - engagement projections 98 - recesses X - axis of rotation

Claims (10)

Refrigerant pump unit with a drive motor (2) and a centrifugal pump (4), characterized in that the centrifugal pump (4) by a tubular container (18) is surrounded, which with a first axial end sealingly connected to the motor housing of the drive motor (2) and is formed closed at its opposite axial end (20). Refrigerant pump unit according to claim 1, characterized in that the tubular container (18) has a suction (24) and a pressure port (26). Refrigerant pump unit according to claim 2, characterized in that the suction port (24) and / or the pressure port (26) extend in the radial direction of the container (18) away. Refrigerant pump unit according to one of the preceding claims, characterized in that the container (18) has a closed wall. Refrigerant pump unit according to claim 3 or 4, characterized in that the suction port (24) and / or the pressure port (26) with connecting flanges (30) are provided. Refrigerant pump unit according to one of claims 3 to 5, characterized in that the suction port (24) and / or the pressure port (26) are designed for direct welding to a connecting line. Refrigerant pump unit according to one of the preceding claims, characterized in that in the container (18) an annular partition (25) is arranged, which separates the suction (24) and the pressure side (26) of the centrifugal pump (4) from each other. Refrigerant pump unit according to one of the preceding claims, characterized in that the container (18) with the motor housing of the drive motor (2) is detachably connected. Refrigerant pump unit according to one of the preceding claims, characterized in that the drive motor (2) is a canned motor. Refrigerant pump unit according to one of the preceding claims, characterized in that the container (18) pressure-resistant for the system pressure of the refrigerant to be delivered is formed.

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