Compressor with electric disc rotor with a pressure reducer for the motor gap and heat pump

Abstract

Compressor, with an electric disc motor with the following features: a rotor (10) comprising a moving element (105) comprising a paddle wheel; a stator (20) arranged with respect to the rotor (10) such that a motor gap (30) is formed between the rotor (10) and the stator (20), wherein the electric disc motor is configured to convey a gas through the impeller from a source region (90) to a target region (100), wherein a target pressure in the target region (100) is higher than a source pressure in the source region (90), wherein the electric disc motor has a pressure reducer (140) for reducing a pressure acting on the rotor (10) due to the different pressures in the source region (90) and in the target region (100), wherein the pressure reducer (140) is designed such that a pressure in the motor gap (30) is less than the target pressure and greater than or equal to the source pressure, wherein the pressure reducer (140) has a first flow resistance (140a) between the target area (100) and the motor gap (30) and a second flow resistance (140b) between the motor gap (30) and the source area (90), wherein the first flow resistance (140a) is greater than the second flow resistance (140b), and wherein the second flow resistance (140b) of the pressure reducer (140) has a bore (200) in the moving element (105) to provide a passage for the gas from the motor gap (30) to the source area (90) through the rotor (10).

Description

[0001] The present invention relates to compressors with an electric motor and in particular to compressors with electric disc motors as well as to a heat pump.

[0002] EP 2 549 113 A2 discloses a magnetic rotor and a rotary pump with a magnetic rotor. The rotor is magnetically driven and mounted within a pump housing inside a stator of the rotary pump for pumping a fluid without physical contact. The rotor is also encapsulated by an outer encapsulation containing a fluorinated hydrocarbon. Inside the encapsulation, the rotor comprises a permanent magnet encased in a metal shell. The rotary pump includes a pump housing with an inlet for supplying a fluid and an outlet for discharging the fluid. The fluid is, for example, a chemically aggressive acid containing a gas, such as sulfuric acid with ozone. For pumping the fluid, a magnetic rotor is magnetically mounted within the pump housing without physical contact. The rotor is further equipped with a magnetic drive comprising electrical coils.The stator is made of laminated iron, which is magnetically connected to the rotor's permanent magnet. The drive is a bearingless motor, in which the stator serves simultaneously as both the bearing and drive stator. The rotor is a disc rotor, with its axial height being less than or equal to half its diameter.

[0003] The ETH dissertation No. 12870, "The Bearingless Disc Motor," by N. Barletta, 1998, discloses magnetically levitated disc motors. Magnetic bearings operate completely without contact, wear, maintenance, or lubrication. Two controllable electromagnets, including electronic control, are required for the active stabilization of one degree of freedom. The bearingless disc motor is used within a bearingless blood pump as a bearingless disc motor with an active axial bearing, as a miniature disc motor, or as a bearingless bioreactor. By combining passive reluctance magnetic bearings and a bearingless motor, it is possible to fully support a disc rotor with only two actively stabilized radial degrees of freedom. The requirement for a large air gap, necessary in hermetic systems, is met by selecting a bearingless permanent magnet synchronous motor.A bearingless disc motor suitable for driving an axial pump for cardiac support is designed for speeds of 30,000 revolutions per minute, resulting in a smaller size.

[0004] Commercial electric disc motors are also known as "pancake motors." The motor concept described in the two preceding references is characterized by the fact that the stator extends around the rotor. Such motors are also called internal rotor motors.

[0005] The problem with the internal rotor design is that the stator must always be larger than the rotor, meaning that the size and design of the rotor are always limited by the stator housing, or rather, that the rotor dominates the design of the stator. This limits the application range of such a disc motor designed as an internal rotor.

[0006] Furthermore, disc motors inherently suffer from the problem that the rotor, regardless of whether it is designed as an internal or external rotor, is subjected to pressure differentials or pressures in certain directions. These pressures cause a bearing to be loaded in the direction of the pressure acting on the rotor, thus increasing wear. Alternatively, if rotor deflection is permitted, the rotor will deflect in this direction, necessitating the provision of clearance for this deflection. Particularly when the pump is used to transfer a medium from a pressure zone with a lower pressure to a pressure zone with a lower pressure, or even to generate such a pressure differential in the first place, complex design measures must be implemented to either achieve the required wear resistance or to provide sufficient clearance for the resulting deflection.

[0007] All of this leads to an increase in the design complexity of the disc motor, and thus also an increase in its susceptibility to errors, while at the same time restricting its area of ​​application.

[0008] DE 10 2013 217 261 A1 discloses a compressor for a heat pump circuit and / or refrigeration circuit, comprising a housing and a rotor rotatably mounted about an axis of rotation, wherein the housing is arranged at least partially circumferentially of the rotor, wherein the rotor comprises at least one hub and at least one blade arranged radially outside the hub, wherein the blade is configured to convey a main fluid flow, wherein the rotor comprises a cover band arranged radially outside the blade, wherein the cover band is arranged radially spaced from the housing, wherein a bearing structure is provided radially outside the cover band, which is configured to form a bearing fluid flow between the cover band and the housing to form a fluid dynamic bearing for supporting the rotor in the housing.

[0009] DE 10 2006 056 799 A1 discloses that, for the rapid and cost-effective production of workpieces with magnets, permanent magnets are placed in a mold. Reinforcing material is then added to strengthen one or more selected areas. A liquid casting material is then injected into the mold, the temperature of which is below the Curie temperature of the permanent magnets. After the casting material has cooled, the workpiece containing the permanent magnets and the hardened casting material is removed from the mold. In particular, the cost-effective production of a workpiece comprising a radial gear, a shaft, a motor / generator section, a bearing, and a countersink is achieved through the use of plastic and plastic injection molding technology, as well as by incorporating reinforcing fibers, which are also placed in the mold before injection molding.

[0010] From US 5 106 273 A, a vacuum pump with an integrated electric motor is known, comprising a stator, a bell-shaped rotor mounted on a central projecting projection of the stator via magnetic bearings, and a number of blades arranged on a radial outer circumference of the rotor alternately with blades arranged on an inner circumference of the stator, wherein the stator and rotor are arranged between an axial suction inlet and an axial outlet of the pump.

[0011] The object of the present invention is to create a compressor with an improved disc motor concept.

[0012] This problem is solved by a compressor with an electric disc motor according to claim 1 and a heat pump according to claim 20.

[0013] In one respect, the electric disc motor is designed as an external rotor motor. This means that the rotor has a recess in which the stator is located. The rotor then rotates around the stator. This allows the rotor design to be defined directly by its application, rather than always requiring, as with an internal rotor motor, the addition of a stator housing with corresponding magnetic coils. Furthermore, the disc motor is media- and pressure-separated by encapsulating the stator within the motor gap between the rotor and stator, thus completely isolating the stator from the surrounding media and pressure.This allows all coil connections for the motor coils in the stator to be routed out of the motor without any problems, because the entire stator area is at ambient pressure and / or in the ambient medium, and not in the pumping zone where the rotor is located. This also avoids overvoltage problems and similar effects that occur when high voltages are used in low-pressure areas, because the adjacent stator coils are all separated from the low-pressure area by the encapsulation material located in the motor gap. This is particularly important when the rotor operates in a low-pressure area, such as below 100 mbar, which occurs when the rotor is used as a compressor element in a heat pump that uses water as the working medium. However, even when the rotor operates at a higher pressure than the stator, the media / circuit pressure is still a concern.Pressure separation through an encapsulation material in the engine gap is of particular advantage.

[0014] By using an external rotor in conjunction with media / pressure separation through an encapsulation material in the motor gap, an electric disc motor is created that can be manufactured with minimal structural complexity, avoids the problems associated with overvoltage effects that would occur when coils are subjected to relatively high voltage in low-pressure areas, and is particularly well-suited for high speeds. This latter advantage arises from the fact that the permanent magnets attached to the rotor, which define the magnetic gap on the rotor side, are supported "outwardly" by the rotor material itself. This is especially important at high speeds, such as those exceeding 50,000 revolutions per minute, because the centrifugal forces occurring at these speeds can be problematic, particularly in internal rotor motors, requiring the permanent magnets to be secured with considerable effort.

[0015] On the other hand, the larger rotor diameter, due to the rotor being arranged around the stator, is particularly advantageous at speeds above 50,000 revolutions per minute, because, as with a gyroscope, it further stabilizes the rotation of the rotor itself and its axis of rotation. This effect is less pronounced or absent in electric disc motors with relatively small rotor diameters, such as those used in internal rotor motors.

[0016] In another aspect, the electric disc motor is used as either an external or internal rotor motor. It has a rotor, which contains a moving element, and a stator, which is positioned relative to the rotor such that a motor gap is formed between the rotor and the stator. The electric disc motor is designed to convey a medium from a source area to a target area through the moving element, where the target pressure in the target area is higher than the source pressure. According to this aspect, the pressure acting on the rotor due to the pressure difference is reduced by a pressure reducer, such that the pressure in the motor gap, i.e., where the magnetic interaction between the rotor and stator takes place, is lower than the target pressure and greater than or equal to the source pressure.This ensures that the rotor is no longer, or at least less, stressed in a certain direction due to the pressure difference between source pressure and target pressure, which would otherwise lead to a resulting pressure and thus to a deflection or increased wear of the bearing.

[0017] This means that while the rotor can generate the required pressure difference between the inlet and outlet, i.e., between the source and target areas, no such pressure difference, or only a reduced one, exists in the motor gap and thus in the area of ​​interaction between the rotor and stator. Using the example of a bearingless motor that is only passively supported axially, for example by a magnetic bearing, this reduces or even eliminates axial deflection due to the operation of the electric disc motor.

[0018] However, even in the case of a contact-mounted rotor, i.e., a rotor supported by a ball bearing, pressure reduction prevents the pressure from being transferred to the bearing and increasing bearing wear. Pressure reduction in the motor gap thus leads to a reduction in motor and bearing wear. In the case of wear-free bearings (i.e., non-contact bearings), it also means that the necessary clearances for rotor deflection due to the resulting pressure on the rotor in a specific axial or radial direction can be reduced. This is because, due to the rotor's operation, such deflections either do not occur or are very small compared to a situation where no specific mechanical pressure reduction is implemented.

[0019] Pressure reduction in the motor gap is equally beneficial for both external and internal rotor motors. Even with an internal rotor, it is advantageous that the rotor does not experience significantly greater deflection during operation than when stationary. This allows for a reduction in clearances, i.e., clearances between the rotor and a guide element that limits the fluid flow area in which the rotor operates.

[0020] In preferred embodiments, the pressure reduction is achieved by two flow resistances: a first flow resistance located between the target area and the engine gap, and a second flow resistance located between the engine gap and the source area. In particular, the flow resistance between the engine gap and the target area is designed to be greater than the flow resistance between the engine gap and the source area, so that the flow resistance between the engine gap and the target area reduces the pressure, while the flow resistance between the engine gap and the source area ensures that the lower pressure acting in the engine gap is the same as that acting in the source area.Particularly when the motor is designed as an external rotor, such that the stator is arranged in a recess of the rotor, it is preferred to position the flux resistance between the target area and the motor gap as far out on the rotor as possible, so that as large a portion of the rotor surface as possible, opposite the stator, is located in an area exposed to the low source pressure or a pressure lower than the target pressure. Conversely, it is preferred to position the second flux resistance between the motor gap and the source area as centrally as possible, i.e., relatively in the middle of the rotor, to achieve conditions as uniform as possible around the circumference of the motor gap.

[0021] In preferred embodiments, the pressure reducer comprises a labyrinth seal between the target area and the motor gap, which creates a defined and relatively high flux resistance, and alternatively or additionally a bore in the rotor between the motor gap and the source area, which creates a relatively low flux resistance. Even the use of either only a labyrinth seal or only a bore, i.e., the use of only one flux resistance between the source area and the motor gap or the target area and the motor gap, already leads to a pressure reduction in the motor gap and thus to a reduced deflection of the rotor relative to the stator during operation in the case of a non-contact magnetic bearing, and especially in the case of an axially passive bearing, or to a reduction in wear in the case of a contact bearing, such as a ball bearing, due to the reduced load during operation.

[0022] The first aspect of the encapsulation material in the motor gap and the second aspect of the pressure reducer can preferably be combined, such that an external rotor disc motor incorporates both the encapsulation in the motor gap and the pressure reducer. However, the two aspects can also be used interchangeably and, with regard to the pressure reducer, not only for external rotors but also for internal rotors. Furthermore, both aspects can be used separately or together for contact bearings, although the use of magnetically levitated rotors is preferred, and in particular axially passive bearings, i.e., axially unregulated bearings and radially actively regulated magnetic bearings.

[0023] Preferred embodiments of the present invention are explained in detail below with reference to the accompanying drawings. These show: Fig. 1A an outrunner according to a first aspect; Fig. 1B an electric disc motor according to a second aspect, designed as an external rotor or internal rotor; Fig. 1C an internal runner according to the second aspect; Fig. 1D a preferred implementation of the second aspect with two series-connected flux resistors; Fig. 2A a cross-section through an electric disc motor according to the first aspect; Fig. 2B a cross-section through an electric disc motor according to the second aspect in which the first aspect is also realized; Fig. 3 a cross-section through a detailed representation of an implementation of flow resistance using a labyrinth seal; Fig. 4 a schematic representation of a rotor and the forces acting on it with regard to the second aspect; Fig. 5 a schematic representation of a magnetic bearing using the example of an internal rotor; Fig. 6 a cross-sectional view of an outer rotor with an increased return element; and Fig. 7 a schematic cross-section through a heat pump with the electric disc motor according to the first or second aspect.

[0024] Fig. Figure 1A shows a cross-section through a schematically represented electric disc motor with a rotor 10, which has a moving element. A stator 20 is also present, the stator 20 being arranged relative to the rotor 10 such that a motor gap 30 exists between the rotor and the stator. The rotor 10 further includes a recess 40 in which the stator 20 is arranged.

[0025] Furthermore, the rotor 10 is arranged in a first region 50 with a first pressure p1. The stator is also arranged in a second region 60, which has a second pressure p3 that differs from the first pressure p1. In the Fig. In the embodiment shown in 1A, the first pressure is, for example, the pressure inside the electric disc motor of Fig. 1A. In contrast, the second pressure is, for example, ambient pressure or atmospheric pressure if the disc motor is located in the atmosphere, or a pressure different from atmospheric pressure if the disc motor is located in an area with a pressure different from atmospheric pressure. Furthermore, an encapsulation material 70 is arranged in the motor gap 30, by which the first area 50 is separated from the second area 60. The separation occurs, for example, by the fact that the encapsulation material is located in the Fig. In the embodiment shown in 1A, the stator is completely enclosed, and connecting leads 80 for the coils, which are attached to the stator and which are in Fig. 1A, which are not shown, are used to supply the coils with electrical power. The leads are routed through the encapsulation material to the outside, i.e., into the second area 60. The electric disc motor is designed as a conveying motor and includes an inlet 90 for a working medium and an outlet 150 for the working medium conveyed by the disc motor. As shown in Fig. As shown in Figure 1A, the pressure inside the disc motor, p1, differs from the pressure outside the disc motor, p3. Preferably, the pressure p1 inside the disc motor is lower than the pressure outside the disc motor. Likewise, the pressure outside the disc motor can be lower than the pressure inside, i.e., within the motor housing.

[0026] In particular, in Fig. Figure 1A further shows that the rotor and the stator are arranged in a motor housing 110, the motor housing having an opening through which the encapsulation material 70 extends. The encapsulation material, or an element to which the encapsulation material is connected, is attached to the motor housing 110 by a schematically depicted sealing ring 120, so that a pressure-tight connection exists between the encapsulation material 70 and the motor housing 110 via the sealing ring 120, which can, for example, be an O-ring. Thus, in Fig. 1A An external rotor is implemented as an exemplary electric disc motor in which the rotor moves within a motor housing, while the stator coils, and in particular the area of ​​the stator located at the motor gap, do not communicate with the internal pressure p1 of the disc motor, but rather with the external pressure. This is particularly advantageous with regard to the electrical supply of the coils typically located in the stator. Especially when the internal pressure p1 is lower than the external pressure p3, it offers significant advantages with regard to coil flashovers and other effects that the coils are not located in the low-pressure region, but are encapsulated from it.

[0027] Furthermore, encapsulating the coils in relation to the interior of the disc motor offers advantages in that the coils do not come into contact with the medium being conveyed and are therefore not exposed to corrosion due to the medium being conveyed, which can be, for example, water or steam. Fig. Figure 1A further shows that the rotor 10 is provided with permanent magnets 130 which are opposite the stator-side area, which typically has stator-side poles on which magnetic coils are wound, in order to define the motor gap 30.

[0028] Fig. Figure 1B shows an electric disc motor according to a second aspect, which also has a rotor 10 facing a stator 20 to define the motor gap 30. In particular, the second aspect, which is shown in Fig. As shown in 1B, the electric disc motor is designed to move the element to be moved, which is connected to the rotor 10 and which is in Fig. Figure 1B, together with the rotor 10, is designed to convey a medium from an inlet 90, or source region 90, where a lower pressure prevails, to a target region 100, or outlet 100, where the target region has a higher pressure, or more generally, a higher pressure than the source region. Furthermore, the electric switching motor is configured to include a pressure reducer 140, which is designed to reduce the pressure acting on the rotor due to the pressure differential between the source and target regions. Specifically, the pressure reducer is configured such that the pressure in the motor gap 30 is lower than the target pressure, or the higher pressure, but greater than or equal to the source pressure.The pressure reducer 140 is therefore designed to reduce the pressure in the motor gap 30 compared to a situation where the pressure reducer is not present, relative to the higher pressure in the target area, and to optimally equalize the pressure in the source area or to bring it between the target pressure and the source pressure.

[0029] Fig. 1C shows an alternative implementation of the electric disc motor from Fig. 1B, in which a stator 20 is again present, which now forms part of the motor housing 110. The stator is further equipped with coils 150, which are opposite the permanent magnets 130 of the rotor 10, in order to again form the motor gap 30. Furthermore, the rotor 10 is connected to a movable element 105, which is formed here above the rotor and connected to the rotor. The pressure reducer 140 is again provided to reduce the pressure in the motor gap 30, specifically with respect to the pressure in the target area, i.e., the pressure at the outlet 100.

[0030] As it is in Fig. As shown in Figure 1D, the pressure reducer 140 includes, by way of example, a first flow resistance 140a between the target region 100 and the motor gap 30, and a second flow resistance 140b between the motor gap 30 and the source region 90 or the inlet 90. Preferably, both flow resistances 140a and 140b are present. Depending on the implementation, however, it may be sufficient to reduce the pressure acting on the rotor due to the operation of the disc rotor by providing only the first flow resistance between the target region and the motor gap, or, alternatively, the second flow resistance 140b between the motor gap and the source region. Preferably, if both flow resistances 140a and 140b are provided, the first flow resistance 140a has a higher value than the second flow resistance 140b.This means that the pressure in the motor gap 30 preferably differs more from the high pressure in the target area 100 than the pressure in the motor gap 30 differs from the pressure in the source area when the electric disc motor is operated.

[0031] Fig. Figure 2A shows a preferred embodiment of the electric disc motor according to the first aspect by way of an embodiment for a radial wheel compressor which can be used at high speeds above 50,000 revolutions per minute and up to, for example, 90,000 revolutions per minute within a heat pump which can be operated with, for example, water as the working medium.

[0032] Fig. Figure 2A shows an implementation of the disc motor according to the first aspect, in which the stator 20 is encapsulated with the encapsulation material 70, so that the media separation between the high and low pressure areas takes place via the motor gap 30. The stator 20 is provided with coils which are in Fig. 2A are not shown, but are located in the surrounding area 60 via the access lines 80, which extend through the encapsulation material 70, or, if the encapsulation material only encapsulates the motor gap and parts of the stator, are already located there.

[0033] The rotor, which is formed by the permanent magnets 130, a return element 160 comprising the permanent magnets, and a banding 170 attached as an additional safety measure, is further connected to the moving element 105, which is located in Fig. 2A is shown schematically as a radial wheel with blades. In particular, the electric disc motor is designed to rotate the radial wheel 105 and the rotor 10 within a guide element 180, which is spaced from the respective blade ends of the radial wheel 105 by a clearance 190. The radial wheel is designed to typically bring steam from an evaporator, in which a lower pressure p0 prevails, to a first pressure p1. This first pressure p1 typically prevails at an outlet of the radial wheel, which is also referred to as an impeller, as shown in Fig. 2A is shown schematically. Typically, the guide element is coupled to a guide chamber, so that the steam accelerated by the rotation of the radial wheel is brought into the guide chamber, and there, due to the continuous delivery of steam by the radial wheel, is brought to a higher target pressure p2, which prevails in the condenser of the heat pump, as shown in Fig. 2A is shown. In the case of the external rotor, the height of the electrically effective stator 20 is less than the diameter of the stator and preferably less than half the diameter of the stator. If, on the other hand, the internal rotor is considered, then in this case, when Fig. 1C is taken as a reference, the height of the electrically effective rotor is preferably smaller than the diameter of the electrically effective rotor and preferably even smaller than half the diameter of the rotor.

[0034] Fig. Figure 2B shows an embodiment of the electric disc motor according to the second aspect, in connection with an application for a radial wheel of a compressor of a heat pump, as shown by Fig. 2A has been shown. In addition to the ones in Fig. The elements shown in 2A are present in the Fig. In the embodiment shown in 2B, the two flux resistances 140a, 140b are further shown, which are based on Fig. 1D described, formed. In particular, the pressure reducer 140 includes the one described in Fig. In the exemplary embodiment shown in Figure 2B, the second flow resistance 140b is a bore 200 in the rotor 105, which is designed to allow media passage from the motor gap 40 to the source area or inlet 90 in the compressor. This makes it possible for media to pass through the moving element 105, which is connected to the rotor.

[0035] Furthermore, in the Fig. The embodiment of the pressure reducer 140 shown in Figure 2B is designed to have a plurality of construction elements 210a, 210b, 210c, which are located between the target area or the outlet from the radial wheel, which is also equipped with 100 in Fig. 2B is shown, and the motor gap 30 is present. Through the interaction of the majority of construction elements 210a-210c, a pressure drop is achieved from the target area 100, which has a pressure p1, to the motor gap, which has a pressure p 1' exhibits a pressure that is smaller than p1 and greater than or equal to the pressure p0 in the source region, i.e., at inlet 90. In particular, a first design element of the plurality of design elements is attached to the rotor. This design element is located in the Fig. In the embodiment shown in Figure 2B, the structural element is 210b. Furthermore, one of the multiple structural elements is attached to a motor housing, such as the motor housing 110, and this structural element is designated as structural element 210a or 210c. The two structural elements, which are projecting rings with a cross-section of Fig. The components shown in 2B are designed and arranged so that their interaction causes a pressure drop. In particular, the structural elements 210a-210c form a labyrinth seal. In the case of the Fig. In the embodiment shown in Figure 2B, the structural elements are each designed as projecting rings. However, they can also be designed as alternative structural elements that project from a surface of the motor housing 110 on the one hand and the rotor or the element to be moved on the other hand, in order to interact in such a way that the rotor can be rotated relative to the motor housing, and in such a way that, due to the close proximity of the structural elements to each other, a pressure drop occurs, so that the pressure p 1' The pressure inside the labyrinth seal with the construction elements 210a-210c is smaller than the pressure p1 outside the labyrinth seal.

[0036] Fig. Figure 3 shows an alternative, enlarged-scale representation of the embodiment of Fig. 2B. Further construction elements 212a-212d are also formed, wherein construction elements 212a and 212c are again arranged on the housing 210, and construction elements 212b and 212d are arranged on the housing 210 and the moving element 105, respectively. In contrast to construction elements 210a to 210c and 210d of Fig. 3, which extend radially with respect to a rotation of the rotor, the structural elements 212a-212d are arranged axially with respect to a rotation of the rotor 10. In one implementation, both radial and axial or alternatively oriented structural elements can be provided as a labyrinth seal, or only radial structural elements 210a-212d, or only axial structural elements 212a-212d, or only structural elements formed in other directions.

[0037] Furthermore, it is not necessarily required that only a relatively small number of construction elements, such as in Fig. Figure 2B shows that the components do not necessarily interact with each other; rather, more or even fewer components can interact, for example, only two components or four or more. Furthermore, it is also possible that more components are attached to the rotor than to the housing, or vice versa.

[0038] In one implementation, the structural elements could also be placed between the rotor and stator, outside the motor gap. However, this is not the case in the application in Fig. 2B, or preferably overall, structural elements are to be installed between the rotor / moving element and the motor housing, since then the structural elements or the associated flux resistance R1 140a are positioned as far outwards as possible with respect to the rotor between the target area 100 and the motor gap 30, while at the same time the second flux resistance, i.e. the bore 200 through the rotor, is positioned as far inwards as possible and preferably even directly axially within the rotor. This ensures that the largest possible area of ​​the rotor, namely at the top where in Fig. In the orientation shown in Figure 2B, which is also a preferred orientation for this disc motor in a heat pump compressor application, the rotor is not subjected to the target pressure p1, but only to the reduced pressure p1'. Therefore, the operation of the rotor, which ultimately generates the different pressures p1 and p0, will not cause any downward deflection of the rotor, or only a very small deflection. This allows the clearance 190 between the guide element 180 and the radial wheel 105 to be kept very small, resulting in a compressor with good efficiency.

[0039] On the other hand, the small deflection of the radial wheel in the axial direction, i.e., when in Fig. As shown in example 2B below, the rotor can be magnetically supported, and in particular with a magnetic bearing that is passive in the axial direction, i.e., not controlled in this direction, but only in the radial direction. Thus, control is only required with respect to a single direction, namely the radial one. This results in an electric disc motor which, despite the considerable speeds it is capable of achieving, has a simple bearing control concept, since axial bearing control is not necessary. Nevertheless, the rotor can be operated with a small clearance to the guide element 180 to achieve high efficiency.

[0040] Fig. Figure 4 shows a schematic representation of the forces acting on the rotor. The rotor 10, or rather the moving element 105, is again schematically depicted as a radial wheel in cross-section. For clarity, the individual blades are not shown in detail, but their function is immediately obvious to those skilled in the art. When the rotor is operating, a low evaporation pressure p0 exists in the source region, while a higher pressure p1 is present at the outlet of the radial wheel in the target region. This pressure is increased to the even higher condenser pressure by the guide chamber adjacent to the radial wheel. The outlet pressure p1 exerts a force F1 on the relatively large upper surface of the radial wheel, which is equal to the product of p1 and the area A1, i.e., the area shown in the top view of the rotor 101.

[0041] In addition, a small pressure F0 acts on the rotor from below, which is equal to the product of the low source pressure p0 and the relatively small area A0.

[0042] In addition, a weight force F acts g on the rotor, which is equal to the mass of the rotor m R times the acceleration due to gravity g. In addition, a force F also acts on it. MThe force then shifts upwards, corresponding to the change in mass over time multiplied by the velocity of the mass flow drawn in from bottom to top by the radial wheel. The force of gravity and the force due to the mass flow are externally determined. The same applies to the dimensions of areas A0 and A1. However, according to the present invention, the pressure reducer 140 lowers the pressure p1. This minimizes the difference between p0 · A0 - p1 · A1. Consequently, the total force acting on the rotor or the moving element due to rotor operation is reduced as much as possible, which in turn leads to a reduced rotor deflection when the rotor is in operation. If no deflection is permitted due to a contact bearing, such as a ball bearing, the pressure on the bearing is reduced.

[0043] Preferably, the rotor is supported relative to the stator by a magnetic bearing, as exemplified in Fig. 5 is shown. Fig. Figure 5 shows the two directions axial 250 and radial 260. A motor with a motor gap 40 exists, and the rotor is held axially relative to the stator by the permanent magnets on the rotor side and the electrical coils on the stator side, without any specific control. However, a radial sensing device 270 and a radial control / regulation device 280 are provided. The radial sensing device 270 detects the position of the rotor relative to the stator, and vice versa, via sensing lines 271. The result of the radial sensing device 270 is communicated to the radial control / regulation device 280 via a sensor line 272. Depending on the implementation, the radial control / regulation device generates corresponding actuator signals via actuator signal lines 273 at the rotor or the stator.However, it is preferred to control only the rotor in order to position it relative to the stator based on the actuator signal 273, such that the motor gap 40 has a similar size around the entire rotor and the rotor does not touch the stator.

[0044] At the in Fig. In the embodiment shown in Figure 5, the rotor can be on the inside and the stator on the outside. In this case, it is an internal rotor. However, the inner element can also be the stator and the outer element the rotor, making it an external rotor. In principle, the magnetic bearing is similar in both cases in that axial control does not occur, while radial control is achieved by the radial sensing device 270 and the radial control / regulating device 280.

[0045] Fig. Figure 6 shows a cross-section through a preferred rotor, which is formed in multiple sections. In particular, the rotor comprises the moving element 105, which in preferred embodiments of the present invention is made of a non-ferromagnetic material, such as plastic or aluminum. The moving element is, for example, a paddle wheel or...

[0046] Impeller of a turbo compressor, such as those used in a heat pump.

[0047] In contrast, the rotor 10, which comprises the permanent magnets 130, the ring-shaped return element surrounding the permanent magnets 130, and the bandage 170 arranged above it, is made of a different material than the element to be moved. In particular, the permanent magnets are made of a specific material suitable for permanent magnets. The return element is ring-shaped and made of a ferromagnetic material, and the bandage 170 is preferably made of carbon material.

[0048] At the in Fig. In the embodiment shown in Figure 6, the permanent magnets 130 partially protrude over a first flat side 105a, in which the recess 40 is formed. The moving element 105 also has a second "flat" side 105b, which, however, has a smaller diameter than the first side 105a. This second "flat" side can also be considered if, for illustrative purposes, the recess 40 is disregarded, and if the projection in the form of a circumferential spring 276 is also disregarded. Preferably, however, the spring 276 engages in an annular groove 278 provided in the return element 160, so that the projection 276 and the groove 278 engage. Depending on the embodiment, however, a spring can also be provided in the return element and the groove in the moving element 105 or in the first "flat" side 105a.This gives the connection between the return element, permanent magnet, and bandage structural stability with the moving element 105, creating a stable overall structure that retains its shape and structure even at high rotational speeds. In particular, the recess 40 further ensures that the permanent magnets and the return element press against the rotor material due to centrifugal forces, so that the connection between the return element and the rotor material becomes increasingly strong as the rotational speed increases.

[0049] Regarding the dimensions, it is preferred that the motor gap 40 be less than 1.5 mm, wherein, in the case of encapsulation in the motor gap, the distance between the encapsulation material and the permanent magnets is less than 1.5 mm. Furthermore, it is preferred that the diameter of the stator 20 be between 3 cm and 7 cm, or that the height of the stator be less than 4 cm. The electric disc motor is also designed to operate at a speed greater than 50,000 revolutions per minute. The bore 200 preferably has a diameter between 1 and 4 mm. Additionally, the clearance 190 between the guide element 180 and the impeller 105 is preferably less than 1.5 mm.

[0050] Furthermore, as is particularly evident in Fig. As shown in Figure 6, preferably the moving element 105 has a first "flat" side 105a facing the stator 20 and a second flat side 105b facing away from the stator 20, the diameter of the first flat side being larger than the diameter of the second flat side. Furthermore, as mentioned, the recess 40 is arranged in the first flat side 105a, with the permanent magnets 130 being at least partially located in the recess 40. In preferred embodiments, it is also advantageous for the return element to have a trapezoidal cross-sectional shape, as shown in Figure 6. Fig. 6 is shown, such that an upper edge of the return element 160 is arranged higher in the axial direction than an upper edge of the permanent magnets 130. This ensures that the permanent magnets 130 are arranged as deep as possible in the recess, while the return element protrudes over the permanent magnets 130 on the side that is connected to the bandage 170.

[0051] Furthermore, as is more clearly stated, for example, in Fig. As shown in Figure 2B, the encapsulation material 70 is not only attached to the stator 20 in the motor gap 40, but also on the underside of the stator 20 in Fig. 2B, i.e., the side of the stator opposite the recess 40. The stator 20 is preferably disk-shaped and has a normal that is parallel to or coincides with the axis of rotation. The flat side of the stator lies opposite a corresponding side of the moving element via the recess 40, and the encapsulation material 70 is also applied to the flat side of the stator in addition to the corresponding sides of the permanent magnets. However, it is not necessary for the encapsulation material to fill the entire area above the stator 20. Instead, it is sufficient for the encapsulation material of the stator to seal against the interior of the electric disc motor.

[0052] Fig. Figure 7 shows a preferred application of the electric disc motor using the example of a heat pump. The heat pump comprises an evaporator 300, a compressor 400, and a condenser 500, wherein the compressor 400 includes the electric disc motor, which, with reference to the Fig. Sections 1A to 6 have been described. In addition to the elements of the disc motor, which, for example, refer to Fig. As shown in Figure 2A, the compressor further comprises a guide chamber 510, which is arranged radially to further convey the working steam supplied by the moving element 105, which has been drawn in by the evaporator 300, and ultimately to increase the pressure to the required pressure in the condensation zone in the condenser 500.

[0053] The liquid to be cooled flows into the evaporator via an evaporator inlet 302. The cooled working liquid flows out of the evaporator via an evaporator outlet 304. To ensure that the radial wheel 105 draws in only steam and not water droplets, a droplet separator 306 is also provided. Due to the low pressure in the evaporator 300, some of the working liquid supplied to the evaporator 300 via the evaporator inlet 302 is evaporated and drawn through the droplet separator 306 over the second side 105b of the radial wheel 105, conveyed upwards, and then discharged into the guide chamber 510. Compressed working steam is introduced from the guide chamber 510 into the condensation zone 510. The condensation zone 510 is further supplied with working fluid to be heated via a condenser inlet 512, which is heated by condensation with the heated steam and is discharged via a condenser outlet 514.Preferably, the condenser is designed as a condenser in the form of a "shower", so that a liquid distribution in the condensation zone 510 is achieved via a distribution device 516, so that the compressed working steam is condensed as efficiently as possible and the heat contained in it is transferred to the liquid in the condensation process.

[0054] At the in Fig. In the embodiment shown in Figure 7, the motor housing 110 also forms the upper housing part of the condenser or liquid condenser 500. Furthermore, as is also shown in Figure 7, the motor housing 110 also forms the upper housing part of the condenser or liquid condenser 500. Fig. As shown in Figure 7, the connecting line 80 for the coils of the stator 20 is connected to a control unit 600 in order to carry out the corresponding speed controls and simultaneously also the active bearing operation via a preferably used magnetic bearing, as shown in the Fig. 5 has been described. The controller also provides the functions of the radial detection 270 and the radial control / regulation 280.

[0055] Although certain elements are described as device elements, it should be noted that this description can equally be seen as a description of steps in a process and vice versa.

[0056] Furthermore, it should be noted that the control is, for example, by element 600 in Fig. 7 or 280 in Fig.5. The control system can be implemented as software or hardware. The control system can be implemented on a non-volatile storage medium, a digital or other storage medium, in particular a floppy disk or CD, containing electronically readable control signals that can interact with a programmable computer system to execute the corresponding method for pumping heat or operating a heat pump. In general, the invention thus also includes a computer program product with program code stored on a machine-readable medium for carrying out the method, provided the computer program product runs on a computer. In other words, the invention can also be realized as a computer program with program code for carrying out the method, provided the computer program runs on a computer. Reference symbol list 10 Rotor 20 Stator 30 engine gap 40 Exclusion 50 first area 60 second area 70 Encapsulation material 80 connecting lines 90 Inlet / Source area 100 Exit / Destination area 105 element to be moved 105a first page 105b second page 110 engine housings 120 seals 130 permanent magnets 140 pressure reducers 140a first flow resistance 140b second flux resistance 150 stator coils 160 Inference element 170 Bandage 180 guide element 190 leeway 200 bore 210a-210d construction elements 212a-212d construction elements 250 Axial direction 260 Radial direction 270 Radial detection device 271 Recording line 272 Control line 273 Actuator line 276 lead 278 Nut 280 Radial control / regulation 300 evaporators 302 Evaporator inlet 304 Evaporator drain 306 droplet separators 400 compressor 410 Conduit path 500 Condenser 510 Condensation zone 512 Condenser inlet 514 Condenser outlet 516 Condenser distributor 600 control

Claims

Compressor, comprising an electric disc motor with the following features: a rotor (10) having a moving element (105) having a paddle wheel; a stator (20) arranged with respect to the rotor (10) such that a motor gap (30) is formed between the rotor (10) and the stator (20), wherein the electric disc motor is configured to convey a gas through the paddle wheel from a source region (90) to a destination region (100), wherein a destination pressure in the destination region (100) is higher than a source pressure in the source region (90), wherein the electric disc motor has a pressure reducer (140) for reducing a pressure acting on the rotor (10) due to the different pressures in the source region (90) and in the destination region (100), wherein the pressure reducer (140) is configured such that a pressure in the motor gap (30) is less than the target pressure and greater than or equal to the source pressure.wherein the pressure reducer (140) has a first flow resistance (140a) between the target region (100) and the motor gap (30) and a second flow resistance (140b) between the motor gap (30) and the source region (90), wherein the first flow resistance (140a) is greater than the second flow resistance (140b), and wherein the second flow resistance (140b) of the pressure reducer (140) has a bore (200) in the moving element (105) to provide a passage for the gas from the motor gap (30) to the source region (90) through the rotor (10). Compressor with electric disc motor according to claim 1, wherein the first flow resistance (140a) of the pressure reducer (140) comprises a plurality of design elements (210a-210d, 212a-212d) between the target area (100) and the motor gap (30) in order to achieve a pressure drop from the target area (100) to the motor gap (30) by means of the plurality of design elements (210a-210d, 212a-212d), wherein a first design element (210b) of the plurality of design elements is attached to the rotor (10) or the element to be moved (105), and wherein a second design element (210a, 210c) of the plurality of design elements is attached to a motor housing (110) opposite the rotor (10) or the element to be moved (105), wherein the two design elements are arranged so close to each other that Together they cause a drop in pressure. Compressor with electric disc motor according to claim 2, wherein the majority of design elements (210a-210d, 212a-212d) are designed as a labyrinth seal between the rotor (10) and the motor housing (110). Compressor with electric disc motor according to claim 1, wherein the first flow resistance (140a) is designed as a labyrinth seal between the motor gap (30) and the target area (100). Compressor with electric disc motor according to claim 4, wherein the rotor (10) has a plurality of permanent magnets (130) on an inner region of the recess (40), wherein furthermore an annular magnetic return element (160) surrounds the permanent magnets (130), so that the permanent magnets (130) are arranged between the return element and the motor gap (30). Compressor with electric disc motor according to one of the preceding claims, wherein the moving element (105) is designed as the impeller connected to the rotor (10), wherein the moving element (105) is furthermore rotatably arranged within a guide element (180), wherein a clearance (190) between the guide element (180) and the impeller is less than 1.5 mm. Compressor with electric disc motor according to one of the preceding claims, wherein the rotor (10) has a recess (40) in which the stator (20) is arranged. Compressor with electric disc motor according to one of the preceding claims, wherein the rotor is actively magnetically supported radially with respect to an axis of rotation of the rotor (10) (270, 280). Compressor with electric disc motor according to one of the preceding claims, wherein the rotor (10) is magnetically passively mounted axially with respect to an axis of rotation of the rotor (10). Compressor with electric disc motor according to one of the preceding claims, wherein the rotor (10) has a plurality of permanent magnets (130), wherein a return element (160) is further connected to the permanent magnets (130), such that the permanent magnets (130) are arranged between the return element (160) and the motor gap (30). Compressor with electric disc motor according to one of the preceding claims, wherein the moving element (105) has a first side (105a) opposite the stator (20) and a second side (105b) facing away from the stator (20), wherein a first diameter of the first side is larger than a second diameter of the second side. Compressor with electric disc motor according to claim 11 in which a recess (40) is arranged in the first side (105a) in which the permanent magnets (130) are at least partially arranged, wherein the permanent magnets (130) are provided on a side facing away from the stator (20) with an annular return element (160). Compressor with electric disc motor according to claim 12, wherein the permanent magnets (130) project at least partially beyond the first side (105a), or wherein the annular return element (160) projects beyond the first side (105a), or wherein the permanent magnets (130) project a first length beyond the first side (105a) and the annular return element (160) projects beyond the first side (105a) by a second length greater than the first length, wherein the pressure reducer (140) has one or more cooperating structural elements (210a-210d, 212a-212d) for pressure reduction in a region projecting beyond the first side and opposite a motor housing part. Compressor with electric disc motor according to one of the preceding claims, wherein the moving element (105) is a radial wheel with blades. Compressor with electric disc motor according to claim 14, wherein the radial wheel has a first side (105a) opposite the stator (20) and a second side (105b) facing away from the stator (20) and arranged in the source region (90), wherein the second flow resistance (140b) of the pressure reducer (140) has the bore (200) in a central region of the radial wheel, and wherein the first flow resistance (140a) of the pressure reducer (140) has one or more cooperating structural elements, wherein at least one structural element is formed on the rotor (10) on the first side and has a diameter larger than the first diameter. Compressor with electric disc motor according to claim 14 or 15, wherein the first flow resistance (140a) of the pressure reducer (140) has a labyrinth seal which has at least one structural element (210a, 210c) on a motor housing (110) and a structural element (210b) on the rotor (10) which are arranged so close to each other that a pressure drop occurs across the interacting structural elements during operation of the electric disc motor. Compressor with electric disc motor according to claim 15 or 16, wherein the structural element on the rotor (10) has a diameter greater than or equal to 1.75 times the first diameter. Compressor with electric disc motor according to one of claims 15 to 17, wherein the structural element is designed as a radially or axially extending projection (210a-210d, 212a-212d). Compressor with electric disc motor according to one of the preceding claims, in which an encapsulation material (70) is arranged in the motor gap (30), by which a first pressure region (50), in which the rotor (10) is arranged and a second pressure region (60), in which the stator (20) is arranged, are separated from each other, wherein the second pressure region (60) differs from the source pressure or the target pressure. Heat pump with the following features: an evaporator (300); a compressor (400) according to one of claims 1 to 19; and a condenser (500). Heat pump according to claim 20, wherein an intake region of the evaporator (300) is connected to a guide element (180) such that, during operation of the electric disc motor, evaporated working fluid is drawn in, wherein, during operation of the heat pump, a source pressure is present in the intake region of the evaporator (300), wherein at a conveying end of the impeller, the first region has a pressure higher than the source pressure, wherein in the condenser (500) there is a condenser pressure greater than the first pressure, and wherein the second pressure in the second region (60) is equal to the condenser pressure or equal to ambient pressure, wherein the source pressure is a pressure in the evaporator (300), and wherein at an outlet (100) of the impeller (105) there is a draw pressure, and wherein a pressure in the condenser (500) is higher than the target pressure.

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