Brushless motor and method for installing a brushless motor

Abstract

The present invention relates to a brushless motor (1), more particularly as a drive for a pump for conveying a fluid, comprising at least one housing (2), at least one stator (3) and at least one rotor (4), wherein: - a fluid can flow through the housing (2) at least in a gap (5) between the stator (3) and the rotor (4) in the housing (2); - the stator (3) is formed in a fluid-tight stator chamber (6); and - the rotor (4) is fluid-tight. In order to provide a compact motor (1) that meets high requirements for sealing against surrounding media, the stator chamber (6) is delimited toward the rotor (4) by at least one inner sleeve (8), and at least one rotor bearing means (9) for supporting the rotor (4) is supported on an inner periphery (10) of the inner sleeve (8).

Description

[0001] “Brushless motor and method for assembling a brushless motor”

[0002] The invention relates to a brushless motor, in particular as a drive for at least one impeller for conveying a fluid. The motor comprises at least one housing, at least one stator, and at least one rotor. A fluid can flow through the housing at least in a gap between the stator and rotor. The housing has corresponding openings at the ends for this purpose. The rotor is fluid-tight, and the stator is arranged in a fluid-tight stator chamber.

[0003] Brushless motors, especially brushless DC motors, are known in the art in a variety of designs. Such motors, especially in small formats, are used, for example, to drive pumps for conveying fluids, such as fuels, in the food industry or in medical technology.

[0004] For example, DE 299 21 352 U1 discloses an intravascular blood pump with an electric motor. An impeller for pumping the fluid is arranged on the motor shaft at a first end of the electric motor. The stator windings are embedded in a synthetic resin matrix. The impeller-less rotor is mounted on a rotor shaft and protected from contact with the fluid by seals.

[0005] DE 10 2010 005 963 A1 discloses a brushless electric motor as a rotary drive for a fuel pump. The rotor has a metal sleeve that hermetically seals the rotor.

[0006] Especially when using generic motors in medical technology, there are numerous challenges regarding motor compactness and fluid sealing. Current motors often fail to meet the increased demands for compact design while simultaneously delivering high performance and efficiency.

[0007] The present invention is based on the object of providing a brushless motor which is particularly compact while offering high performance and which ensures increased requirements for sealing against fluids.

[0008] The above-mentioned object is achieved in a generic motor according to the characterizing part of patent claim 1 in that the stator space is delimited in the direction of the rotor by at least one inner sleeve, and that at least one rotor bearing means for supporting the rotor is supported on an inner circumference of the inner sleeve.

[0009] The housing of the motor is preferably designed such that a fluid, for example a flushing liquid, can flow axially through it between a first end and a second end. The flow through the housing occurs essentially in the gap formed between the stator and the rotor, in particular an annular gap. The gap between the stator and rotor is delimited in the radial direction by the inner sleeve over the entire length of the stator. The inner sleeve is preferably designed such that it radially delimits the entire fluid path within the housing, in particular between a motor flange arranged at a first end and a flushing connection arranged at a second end. The inner sleeve is part of the housing and delimits the gap in the direction of the stator chamber surrounding the rotor. The inner sleeve surrounds a rotor chamber in which the rotor is rotatably arranged, in particular mounted.

[0010] The stator surrounds the rotor, which is rotatable about a motor axis A within a rotor chamber. The motor advantageously has control and / or power electronics that are at least partially arranged in the housing. The control and / or power electronics have at least one circuit board that is arranged, in particular encapsulated, within the housing. The circuit board can preferably be contacted via at least one, preferably at least two, or at least three, connecting lines leading out of the housing.

[0011] In particular, to ensure a compact design of the motor, it is provided that at least one rotor bearing means for supporting the rotor is arranged in particular within the inner sleeve. The rotor bearing means is arranged such that it is supported on an inner circumference of the inner sleeve. Preferably, at least two rotor bearing means are provided for supporting the rotor, wherein both rotor bearing means are supported on a circumference of the inner sleeve. In particular, both rotor bearing means are arranged within the inner sleeve. At least one rotor bearing means is designed, for example, as a ball bearing, magnetic bearing, ceramic bearing or plain bearing. Preferably, at least one rotor bearing means has hydrodynamic lubrication and is designed in particular as a ceramic bearing. Advantageously, both rotor bearing means are designed identically.

[0012] In particular, at least one rotor bearing means is mounted with a sliding fit in the inner sleeve; preferably, both rotor bearing means are mounted with a sliding fit in the inner sleeve. Alternatively, it is provided that at least one rotor bearing, preferably both rotor bearings, are connected, in particular glued, to the inner sleeve.

[0013] Very low friction in the rotor bearings can be achieved by preloading the rotor with a very low preload force in one direction, in particular with at least one wave spring washer. For example, the preload force is exactly or less than 5 N, in particular exactly or less than [N]. Preferably, at least part of the bearing cage, advantageously the entire bearing cage, is made of a biocompatible plastic, in particular polyetheretherketone (PEEK). The arrangement of the rotor bearing means within the inner sleeve has the advantage that no additional installation space is required for the rotor bearing means, which ensures a compact design.

[0014] The invention has the advantage over the prior art that, particularly thanks to the inner sleeve, it meets high safety requirements with regard to fluids while maintaining the compactness of the motor. The at least partial flow of a fluid through the housing during operation ensures advantageous heat dissipation, which, for example, prevents high temperatures on the outside of the housing. The motor is designed very efficiently to prevent excessive heating of the fluid.

[0015] According to a first embodiment of the motor, it has proven advantageous if the rotor bearing means or the rotor bearing means is / are designed and arranged such that the fluid can flow around and / or through it. The rotor bearing means or the rotor bearing means are therefore arranged such that a fluid flowing in the gap between the stator and the rotor at least flows around and / or through it. It is particularly advantageous for this purpose that rotor bearing means designed, for example, as ball bearings are at least partially made of a plastic. The cage is preferably made of a plastic, in particular of polyetheretherketone (PEEK). For example, balls are made of a ceramic and bearing rings - inner ring and / or outer ring - are made of corrosion-resistant steel.

[0016] A further advantageous embodiment of the motor provides for the inner sleeve to be formed in one piece. The inner sleeve preferably extends in one piece from the motor flange at a first end to the opposite, second end of the motor. To ensure biocompatibility of the motor, particularly in medical applications, the inner sleeve is made of a biocompatible plastic. Polyetheretherketone (PEEK) or polytetrafluoroethylene (PTFE) have proven particularly suitable biocompatible plastics. It is also provided for the inner sleeve to be formed in several parts, in particular in two parts, and for the parts of the inner sleeve to be joined together in a materially bonded, in particular fluid-tight, manner, preferably by adhesive or welding.

[0017] The inner sleeve is advantageously designed such that it radially delimits a rotor chamber within the housing. The motor flange is preferably formed at a first end, axially delimiting the rotor chamber and allowing fluid to escape from the housing, in particular from the rotor chamber. At a second end, the rotor chamber is axially delimited, preferably by a flushing connection, through which the fluid can enter the gap between the rotor and stator. The second end of the motor or the housing is sealed with a potting compound, in particular a stress-curing potting compound.

[0018] The design of the inner sleeve influences the efficiency of the motor as well as its size. According to a further embodiment, it is therefore particularly provided that the inner sleeve has a wall thickness of between 0.075 mm and 1 mm, at least in the region between the rotor and stator, in particular along the length of the stator. A wall thickness of between 0.1 mm and 0.5 mm is particularly preferred. The inner sleeve preferably has a constant wall thickness, at least along the length of the stator windings. Such small wall thicknesses pose a challenge for assembly, which is why the invention also claims a method for assembling a motor, as described below.

[0019] The inner sleeve delimits, among other things, the rotor chamber. According to a further embodiment of the motor, at least one outer sleeve is provided on the outside of the housing. The outer sleeve delimits the housing, in particular the stator chamber, in the radial direction on the outside. The housing is designed such that the inner sleeve delimits the stator chamber in the direction of the inner rotor chamber. In the radial direction, the outer sleeve also delimits the housing along its entire circumference. For the outer sleeve, a wall thickness of 0.05 mm and 1 mm, in particular between 0.1 mm and 0.5 mm, has proven particularly advantageous. The outer sleeve is preferably made of a corrosion-resistant steel.

[0020] According to a further embodiment, it has also proven advantageous if a motor flange is arranged on at least one first end side of the motor. The motor flange preferably supports the inner sleeve and the outer sleeve, so that the stator space between the inner sleeve and the outer sleeve is formed as an annular space. The motor flange is preferably glued or welded to the outer sleeve. Laser welding between the outer sleeve and the motor flange is particularly preferred. For example, the motor flange is made of the same material as the outer sleeve.

[0021] The motor flange preferably has a central recess that provides an opening to the rotor chamber to ensure the flow of fluid. In addition, the motor flange has at least one central thread. The motor can be fastened to the thread or the thread serves as an interface for fastening further components to the motor. At least one motor shaft section of the rotor preferably passes through the motor flange. The motor shaft section is designed to drive a shaft, for example, that can be coupled to the motor shaft section. For example, the motor shaft section has means that are designed to interact in a form-fitting manner, in particular for transmitting torque, with a connectable shaft. At least in the operating state of the motor, the motor shaft section is rotatable.

[0022] According to a further embodiment of the motor, the inner sleeve has at least one flange section on the first end side, which in particular lines a central recess of the motor flange on the inside. The flange section is preferably pressed into the recess in the motor flange. The wall thickness in the region of the flange section is preferably increased compared to the wall thickness in the region between the rotor and the stator, in particular at least doubled. Furthermore, at least one section with a reduced diameter is provided in the flange section of the inner sleeve, so that at least one stop edge is provided for a rotor bearing means and / or a mounting ring. The mounting ring is made, for example, from polyetheretherketone (PEEK).

[0023] Preferably, a collar-like extension is formed between the flange section and the section of the inner sleeve with a constant wall thickness that extends between the rotor and stator, preferably extending toward the outer sleeve of the motor. For example, the collar-like extension is arranged such that it rests against the motor flange, particularly at the front. The collar-like extension serves, in particular, to provide electrical insulation from the motor flange and to axially position the coils and the iron return.

[0024] Opposite the first end of the motor, the housing, in particular the stator chamber, is sealed, for example, with at least one potting compound. In particular, at least one connecting cable for the motor and / or a purge connection passes through the potting compound. The purge connection is preferably made of the same material as the outer sleeve. The potting compound preferably fills both the annular space between the outer sleeve and inner sleeve as well as the end region of the inner sleeve. Stress-curing potting compounds have proven particularly advantageous.

[0025] For example, the outer sleeve extends to the end of the housing on the second end side, with the inner sleeve having a slight distance to the end of the housing within the potting compound.

[0026] The use of the potting compound has the advantage that heat is dissipated and that the inner sleeve is supported and stabilized. According to a further embodiment of the motor, it is further provided in particular that at least one centering flange is arranged on the second end side, which positions the inner sleeve and the outer sleeve at a distance from one another. Preferably, the centering flange also serves as a limiting means for the potting compound. Furthermore, it is preferably provided that the stator chamber, in particular the cavities present in the stator chamber, are potted with at least a second potting compound, preferably a stress-curing potting compound, in particular up to the centering flange. Preferably, the centering flange has at least one opening for introducing potting compound.

[0027] The motor, in particular the stator chamber, is thus advantageously redundantly sealed against ambient media, at the first end side by the motor flange and the potting compound in the stator chamber, and at the second end side by the external potting compound and the second potting compound in the stator chamber.

[0028] The flushing connection in the second end region of the housing has at least one connection contour outside the housing, for example for a hose. The connection contour is designed, for example, as a mandrel profile. The flushing connection serves to conduct fluid, for example a flushing liquid, through the potting compound into the housing of the motor, in particular from the inner circumference of the inner sleeve, so that the fluid can flow around the rotor and in the gap between the rotor and stator in the axial direction. The outer diameter of the flushing connection in the region of the inner sleeve preferably has a diameter that matches the inner diameter of the inner sleeve. The flushing connection preferably has a sliding fit to the inner circumference of the inner sleeve.

[0029] In the area of ​​the second end of the motor, at least one circuit board, for example a ring-shaped one, with control and / or power electronics for the motor is preferably arranged in the housing, in particular in the stator chamber. The circuit board is preferably held by a circuit board carrier extending annularly around the outer circumference of the inner sleeve.

[0030] The rotor is preferably mounted entirely within the inner sleeve. According to a further embodiment of the motor, it has also proven advantageous for the rotor to have at least one rotor sleeve, and for the rotor sleeve to have a first shaft extension at a first end and a second shaft extension at a second end. The rotor is preferably mounted on the shaft extensions of the rotor sleeve.

[0031] At least one permanent magnet of the rotor, in particular a plurality of permanent magnets, is arranged within the rotor sleeve. The at least one permanent magnet is arranged in the rotor sleeve, between the first shaft extension and the second shaft extension. The permanent magnet is preferably designed as a solid cylindrical magnet, in particular as a neodymium-iron-boron magnet.

[0032] For example, the rotor sleeve is made of the same material as the outer sleeve of the motor. The first shaft extension and the second shaft extension are also made of this material. For example, the first shaft extension and / or the second shaft extension are welded to the rotor sleeve, in particular by laser welding.

[0033] The first shaft extension on a first end side of the motor projects at least partially into the rotor sleeve and is preferably closed on the inside with a plug, in particular a plug made of polyetheretherketone (PEEK), to prevent the ingress of fluid. The first shaft extension also has a motor shaft section on which, for example, the first bearing means is arranged. In particular, the motor shaft section protrudes from the housing through the motor flange in order to drive, for example, a shaft connectable to the motor shaft section. For example, the connectable shaft is at least partially inserted into the motor shaft section for connection. The motor shaft section represents, in particular, an interface for transmitting torque. The motor shaft section has, for example, at least partially a profiled outer contour or inner contour, in particular an outer square and / or an inner square.

[0034] The second shaft extension on a second end side of the housing also penetrates at least partially into the rotor sleeve and is preferably welded to it. In the end of the second shaft extension oriented towards the second end region, the diameter is reduced such that it corresponds to the inner diameter of the rotor bearing means arranged there. Preferably, the inner diameter of both rotor bearing means is substantially identical. In addition, a spring washer, in particular a corrugated spring washer, is arranged on the second shaft extension and is preferably supported against the scavenging connection in order to mount the rotor in the axial direction with a sliding fit. The rotor is preferably preloaded by the spring washer, in particular with a preload force of equal to or less than 5 N, preferably equal to or less than 3 N. The preload preferably occurs in the direction of the first end side of the motor.Advantageously, the rotor sleeve is connected to the shaft ends in a fluid-tight manner.

[0035] A further embodiment of the motor provides that the first shaft extension has at least one motor shaft section on the first end side. The motor shaft section is at least partially hollow so that a fluid can flow through it. The motor shaft section has an axially extending recess. The motor shaft section is, for example, formed integrally with the first shaft extension. Alternatively, it is also provided that the motor shaft section is attached to the shaft extension. It is also provided that a first motor shaft section, preferably without a recess, is arranged on the first shaft extension, and that a second motor shaft section, in particular as an adapter, can be fastened to the first motor shaft section, wherein the second motor shaft section has a longitudinally extending recess, preferably with a square socket.To further increase the efficiency of the motor, a further embodiment provides for the stator to have a magnetic yoke with a plurality of adjacently arranged individual laminations. The magnetic yoke is arranged between the stator windings and the outer sleeve. The individual laminations are made, for example, of silicon-iron or nickel sheet. The individual laminations of the magnetic yoke preferably have a thickness between 0.05 mm and 0.5 mm. A thickness between 0.05 mm and 0.3 mm is also preferred. A thickness of approximately 0.1 mm or 0.2 mm for each of the individual laminations is particularly preferred.

[0036] Furthermore, it has proven advantageous for efficiency if the stator is provided with at least three or at least four coil pairs. The coils are wound ironless, preferably according to the coreless armature principle. Preferably, two coil pairs, in particular essentially oppositely arranged coil pairs, are connected in series, so that, for example, with six coils, only six winding taps are present. In particular, the coils are interconnected on the circuit board.

[0037] The dimensioning of the gap between the inner sleeve and the rotor has a strong influence on the efficiency of the motor and the fluid losses. According to a further embodiment of the motor, it has therefore proven advantageous if the gap between the rotor and stator has a height of between 0.12 mm and 1.5 mm over at least 50% of the length of the rotor. For example, the gap between the rotor and stator has the aforementioned height at least over the entire length of the rotor sleeve. A gap height of between 0.25 mm and 1 mm is particularly preferred, and a gap height of approximately 0.5 mm is most preferred.

[0038] Furthermore, according to a further embodiment, the efficiency of the motor can be influenced by maintaining a ratio of the outer diameter of the inner sleeve to the outer diameter of the housing between 0.3 and 0.7. A ratio of 0.5 is particularly preferred. Furthermore, for example, the ratio of the outer diameter of the stator winding to the outer diameter of the iron yoke is between 0.6 and 0.9, in particular approximately 0.8.

[0039] The invention further relates to a method for assembling an engine, in particular according to one of the above embodiments, at least comprising the following method steps:

[0040] - Providing a motor flange with an outer sleeve arranged thereon for defining the housing of the motor and an inner sleeve arranged on the motor flange, in particular wherein a flange portion of the inner sleeve enters the motor flange,

[0041] - At least partially filling the stator space between the inner sleeve and the outer sleeve with a first casting compound,

[0042] - arranging the stator windings and the iron return in the stator chamber, in particular on an outer circumference of an inner sleeve, in the first casting compound, in particular one which has not yet solidified,

[0043] - Inserting the rotor together with the rotor bearing means into a rotor space formed by the inner sleeve, so that a motor shaft section of the rotor protrudes from the housing in the area of ​​the motor flange,

[0044] - Arranging a flushing flange, in particular at least partially in the inner sleeve, and at least one centering flange, in particular between the inner sleeve and the outer sleeve,

[0045] - Potting the housing on the second end side with a second potting compound.

[0046] The assembly sequence described above also allows for easy assembly of inner sleeves with very small wall thickness.

[0047] In particular, it is provided that any cavities remaining in the stator chamber after the stator windings and the iron return path have been inserted, in particular up to the centering flange, are filled with potting compound. Preferably, at least one spring washer, in particular a wave spring washer, is applied to the second shaft extension before the flushing flange is arranged. In particular, it is provided that the rotor is preloaded via the flushing flange toward the first end face, that the potting compound is subsequently introduced, and that the preload is released after the potting compound has hardened, so that the rotor remains preloaded between the flushing flange and the first end face.

[0048] Further advantageous embodiments of the invention emerge from the following description of the figures and the dependent subclaims.

[0049] They show:

[0050] Fig. 1 shows an embodiment of a brushless motor according to the invention in a side sectional view, and

[0051] Fig. 2 shows an embodiment of a schematic sequence of a method according to the invention.

[0052] In the various figures of the drawing, identical parts are always provided with the same reference symbols.

[0053] With regard to the following description, it is claimed that the invention is not limited to the exemplary embodiments and not to all or several features of described combinations of features, but rather each individual partial feature of the / each exemplary embodiment is also important for the subject matter of the invention, even independently of all other partial features described in connection therewith, and also in combination with any features of another exemplary embodiment.

[0054] Fig. 1 shows an embodiment of a brushless motor 1 in a sectional side view. The motor 1 is designed in particular as a drive for a connectable shaft, for example with at least one impeller for conveying a fluid. The motor 1 has at least a housing 2, a stator 3 and a rotor 4. The housing 2 is designed such that a fluid can flow through it in a gap 5, in particular an annular gap, between the stator 3 and the rotor 4. For this purpose, the stator 3 is designed in a fluid-tight stator chamber 6. The rotor 4 is also fluid-tight and, during operation, is arranged in a rotor chamber 7 filled with fluid. The gap 5 has a constant height essentially along the extent of the stator 3.

[0055] The stator chamber 6 is delimited in the direction of the rotor 4, in particular in the radial direction, by an inner sleeve 8. The inner sleeve 8 thus also delimits the outer circumference of the rotor chamber 7. The rotor 4 is arranged within the inner sleeve 8, i.e. in the rotor chamber 7, and is mounted by rotor bearing means 9. The rotor 4 can rotate about a motor axis A running centrally through the housing 2. The rotor bearing means 9 are designed as ball bearings with a cage made of polyetheretherketone (PEEK). The bearing outer ring of the rotor bearing means 9 is supported on an inner side 10 of the inner sleeve 8. A sliding fit is formed between the rotor bearing means 9 and the inner sleeve 8. The rotor bearing means 9 are designed so that a fluid flowing in the gap 5 between the rotor 4 and the stator 3 can flow through the rotor bearing means 9.

[0056] The inner sleeve 8 is formed in one piece from polyetheretherketone (PEEK) and delimits the rotor chamber 7 in the radial direction. The inner sleeve 8 delimits the entire space within the housing 2, in which a fluid can flow through the housing 2 in the axial direction. In the region of the extension of the stator 3, the inner sleeve 8 has a constant wall thickness, which is preferably approximately 0.5 mm. The stator chamber 6 is delimited on an outer circumference of the housing 2 by an outer sleeve 11. The outer sleeve 11 is preferably made of a corrosion-resistant steel and has a wall thickness of approximately 0.5 mm.

[0057] The inner sleeve 8 and the outer sleeve 11 are connected to a first end side 12 of the

[0058] Motor 1 is supported by a motor flange 13. The outer sleeve 11 is partially pushed onto the motor flange 13 and welded to it by laser welding. The inner sleeve 8 has a flange section 14 and extends at the first end 12 with the flange section 14 into the motor flange 13 and is preferably pressed into the motor flange 13. The flange section 14 extends in a central recess 16 within the motor flange 13. The inner sleeve 8 extends to the end of the motor flange 13 and is flush with the motor flange 13.

[0059] In the axial direction along the motor axis A, the inner sleeve 8 rests against the motor flange 13 with a collar-like extension 15 at its end. On the other side of the collar-like extension 15, the stator 3 is formed in the stator chamber 6. The wall thickness of the inner sleeve 8 in the region of the flange section 14 is at least twice as large as in the region of the gap 5 between the stator 3 and rotor 4. In addition, the flange section 14 has a region 17 with a reduced diameter to ensure a mounting edge 18 within the flange section 14 for a rotor bearing means 9. The inner diameter in the region 17 corresponds to the inner diameter of the inner sleeve 8 in the region between the stator 3 and rotor 4.

[0060] In this exemplary embodiment, the first rotor bearing means 9 rests against the mounting edge 18, so that the first rotor bearing means 9 is supported in the axial direction. On the second end side 20 of the motor 1 or the housing 2, a centering flange 21 is arranged between the outer circumference of the inner sleeve 8 and the inner circumference of the outer sleeve 11. The centering flange 21 keeps the inner sleeve 8 and the outer sleeve 11 spaced apart from one another. The centering flange 21 also delimits the stator chamber 6 in the axial direction. The stator chamber 6 is completely filled, for example, with a first potting compound 22.

[0061] At the second end 20, the housing 2 or the motor 1 is completely sealed by a second potting compound 23. The second potting compound 23 is flush with the outer sleeve 11. The inner sleeve 8 ends at a distance in the potting compound 23. An electrical connection cable 24 of the motor 1 and a flushing connection 25 arranged on the second end 20 pass through the potting compound 23. The flushing connection 25 has a connection profile 26 on the outside, for example for a hose. On the inside, the flushing connection 25 serves to introduce the fluid flowing in the gap 5 and is inserted in a form-fitting manner into the inner circumference of the inner sleeve 8. The flushing connection 25 bears fully against the inner side 10 of the inner sleeve 8 and preferably forms a sliding fit with the inner sleeve 8. The flow direction of a fluid from the flushing connection 25 to the motor flange 13 is advantageous.

[0062] In the axial direction along the motor axis A, a spring washer 27 is arranged between the rotor 4 and the purge connection 25, which preloads the rotor 4 in the axial direction toward the first end face 12. The rotor bearing means 9 are axially movable within the sliding fit and the spring force of the spring washer 27 and are clamped against each other by the spring force.

[0063] The rotor 4 has a rotor sleeve 28, which is attached to a first shaft extension 29 at the first end 12 and to a second shaft extension 30 at the second end 20. The rotor sleeve 28 is connected to the shaft extensions 29, 30 in a fluid-tight manner by being welded, in particular laser-welded, to the shaft extensions 29, 30. Material can be applied to or removed from the first shaft extension 29 and / or the second shaft extension 30 to balance the rotor 4.

[0064] The first shaft extension 29 on the first end 12 of the motor 1 extends at least partially into the rotor sleeve 28. Furthermore, the first shaft extension 29 has a motor shaft section 31, which protrudes from the housing 2 at the first end 12, for example, to interact with a shaft (not shown) and drive the shaft. The motor shaft section 31 preferably has a square socket (not shown). The motor shaft section 31 is hollow. For manufacturing reasons, the bore in the motor shaft section 31 continues into the area of ​​the rotor sleeve 28 and is closed there with a sealing plug 33, which prevents fluid from entering the rotor 4. A permanent magnet 34 in the form of a solid cylindrical magnet is arranged within the rotor sleeve 28 between the first shaft extension 29 and the second shaft extension 30.

[0065] The second shaft extension 30 also extends at least partially into the rotor sleeve 28. Toward the second end face 20, the second shaft extension 30 has a reduced diameter, so that it can be advantageously mounted in the second rotor bearing means 9.

[0066] The spring washer 27 exerts a spring force on the rotor 4 in the direction of the first end side 12, so that the rotor 4 is pressed against the mounting edge 18 via the rotor bearing means 9 at the first end side 12.

[0067] The stator 3 has a ferrous yoke 35 with a plurality of individual laminations 35a extending side by side in the stator chamber 6. The stator 3 also has an ironless winding 36 with three coil pairs. The winding 36 extends from the collar-like extension 15 at the first end 12 to a circuit board carrier 37 at the second end 20. The circuit board carrier 37 is annular and holds a circuit board 38, which is also annular.

[0068] The circuit board 38 is used for the electrical connection of the coil pairs of motor 1.

[0069] The gap 5 between rotor 4 and stator 3 is dimensioned such that it has a height of approximately 0.5 mm, at least in the area of ​​the extension of the rotor sleeve 28. Such a height of the gap 5 has proven particularly advantageous for the efficiency of the motor 1.

[0070] Fig. 2 shows an embodiment of a schematic sequence of a method 100 according to the invention. To assemble the motor 1, the outer sleeve 11 is first applied to the motor flange 13 and welded to it, and the inner sleeve 8 is pressed with its flange section 14 into the recess 16. The motor flange 13 with the outer sleeve 11 is provided 101. The annular space created between the outer sleeve 11 and the inner sleeve 8 - the stator space 6 - is then filled 102 with a first potting compound 22. The stator windings 36 are introduced 104, together with the iron yoke 35, into the still liquid first potting compound 22. After the centering flange 21 has been introduced, any cavities present in the stator space 6 are filled with the first potting compound 22 so that the second potting compound reaches up to the centering flange.Subsequently, the first rotor bearing means 9, together with the pre-assembled rotor 4, is first inserted 104 into the rotor chamber 7 in the inner sleeve 8 such that the first rotor bearing means 9 rests against the mounting edge 18. The rotor bearing means 9 are supported on the inner side 10 of the inner sleeve 8.

[0071] Subsequently, the spring washer 27 is arranged 105 together with the purge connection 25 in the inner sleeve, and a force is exerted on the purge connection 25 in the direction of the first end 12, so that the rotor 4 is preloaded in the direction of the first end 12. Finally, potting 106 with the second potting compound 23 takes place on the second end 20. The force on the purge connection 25 is maintained until the second potting compound 23 has completely hardened. Preferably, the pre-assembly of the stator 3 up to the insertion of the centering flange 21 and the hardening of the first potting compound 22, as well as the pre-assembly of the rotor 4 including the bearing means 10, takes place outside a clean room. The assembly of the rotor 4 in the stator 3, including the application and hardening of the second potting compound 23, preferably takes place in a clean room.

[0072] The invention is not limited to the illustrated and described embodiments, but also encompasses all equivalent embodiments within the meaning of the invention. It is expressly emphasized that the embodiments are not limited to all features in combination; rather, each individual partial feature can also have an inventive significance in itself, independently of all other partial features. Furthermore, the invention is not yet limited to the combination of features defined in claim 1, but can also be defined by any other combination of specific features of all the individual features disclosed as a whole. This means that, in principle, practically every individual feature of claim 1 can be omitted or replaced by at least one individual feature disclosed elsewhere in the application.

[0073] List of reference symbols

[0074] 1 engine

[0075] 2 housings

[0076] 3 Stator

[0077] 4 Rotor

[0078] 5 gap

[0079] 6 Stator chamber

[0080] 7 Rotor chamber

[0081] 8 inner sleeve

[0082] 9 Rotor bearing means

[0083] 10 Inside of the inner sleeve 8

[0084] 11 Outer sleeve

[0085] 12 First end side of the engine 1

[0086] 13 Motor flange

[0087] 14 Flange section

[0088] 15 Collar-like extension

[0089] 16 Central recess

[0090] 17 Area of ​​the flange section 14

[0091] 18 Mounting edge

[0092] 20 Second end side of the engine 1

[0093] 21 Centering flange

[0094] 22 First casting compound

[0095] 23 Second casting compound

[0096] 24 connecting cable

[0097] 25 Flushing connection

[0098] 26 Connection profile

[0099] 27 Spring washer

[0100] 28 Rotor sleeve

[0101] 29 First wave approach

[0102] 30 Second wave approach

[0103] 31 Motor shaft section Plug Permanent magnet Iron return Individual sheets Ironless winding Board carrier Board

Claims

Claims 1. Brushless motor (1), in particular as a drive for a pump for conveying a fluid, comprising at least one housing (2), at least one stator (3) and at least one rotor (4), wherein the housing (2) is permeable to fluid flow at least in a gap (5) between the stator (3) and rotor (4) in the housing (2), wherein the stator (3) is formed in a fluid-tight stator chamber (6), and wherein the rotor (4) is fluid-tight, characterized in that the stator chamber (6) is bounded in the direction of the rotor (4) by at least one inner sleeve (8), and that at least one rotor bearing means (9) for supporting the rotor (4) is supported on an inner circumference (10) of the inner sleeve (8). Brushless motor (1) according to claim 1, characterized in that the rotor bearing means (9) or rotor bearing means (9) are designed and arranged to allow fluid flow around and / or through them.Brushless motor according to claim 1 or 2, characterized in that the inner sleeve (8) is formed in one piece and / or that the inner sleeve (8) is made of a biocompatible plastic, in particular polyetheretherketone (PEEK) or polytetrafluoroethylene (PTFE). Brushless motor (1 ) according to one of claims 1 to 3, characterized in that at least one outer sleeve (11 ) is provided, that the outer sleeve delimits the stator space (6), in particular the housing (2), preferably that the outer sleeve (11 ) has a wall thickness between 0.05 mm and 1 mm, in particular between 0.1 mm and 0.5 mm, at least in sections; Brushless motor (1 ) according to one of claims 1 to 4, characterized in that a motor flange (13) is arranged on at least one first end side (12) of the motor (1 ), and that the motor flange (13) supports the inner sleeve (8) and the outer sleeve (11 ), in particular that the inner sleeve (8) is at least partially inserted, preferably pressed, into the motor flange (13).Brushless motor (1) according to any one of claims 1 to 5, characterized in that the inner sleeve (8) has a flange section (14) at the first end side (12), in particular wherein the flange section (14) extends at least partially into the motor flange (13). Brushless motor (1) according to any one of claims 1 to 6, characterized in that the inner sleeve (8) has at least one collar-like extension (15) at the first end side (12), in particular that the collar-like extension (15) abuts the motor flange (13), preferably at its end face. Brushless motor (1) according to any one of claims 1 to 7, characterized in that at least one centner flange (21) is arranged at a second end side (20), that the centner flange (21) positions the inner sleeve (8) and the outer sleeve (11) at a distance from each other, in particular that the motor (1), preferably the stator chamber (6), is sealed at the second end side (20) by at least one potting compound (23). Brushless motor (1) according to any one of claims 1 to 8, characterized in that the rotor (4) has at least one rotor sleeve (28), and that the rotor sleeve (28) has a shaft extension (29) at a first end side and a second shaft extension (30) at a second end side (20), preferably that the rotor sleeve is fluid-tightly connected to the shaft extensions, in particular that the rotor bearing means (9) rotatably support the rotor (4) at the shaft extensions (29, 30).Brushless motor (1) according to any one of claims 1 to 9, characterized in that the rotor (4) has at least one permanent magnet (34), in particular a plurality of permanent magnets (34), advantageously that the at least one permanent magnet (34) is arranged in the rotor sleeve (28) and / or is designed as a solid cylindrical magnet. Brushless motor (1) according to any one of claims 1 to 10, characterized in that the first shaft extension (29) at the first end face (12) has a motor shaft section (31), in particular that the motor shaft section (31) is at least partially hollow. Brushless motor (1) according to any one of claims 1 to 11, characterized in that the stator (3) has an iron core (35) with a plurality of individual laminations (35a), in particular that the individual laminations (35a) each have a thickness of between 0.05 mm and 0.5 mm, in particular between 0.05 mm and 0.3 mm, preferably a thickness of about 0.1 mm or 0.2 mm. Brushless motor (1) according to any one of claims 1 to 12, characterized in that the stator (3) has at least three or at least four coil pairs, preferably that the two coils of a coil pair are connected in series.Brushless motor (1) according to any one of claims 1 to 13, characterized in that the ratio of the outer diameter of the inner sleeve (8) to the outer diameter of the housing (2) is at least sectionally between 0.3 and 0.7, in particular about 0.5, and / or that the ratio of the outer diameter of the winding (36) of the stator (3) to the outer diameter of the iron core (35) is between 0.6 and 0.9, in particular about 0.

8. Method (100) for assembling a brushless motor (1), in particular according to any one of claims 1 to 14, comprising at least the following method steps: - Providing (101) a motor flange (13) with an outer sleeve (11) arranged thereon for limiting the housing (2) of the motor (1) and an inner sleeve (8) arranged on the motor flange (13), in particular wherein a flange section (14) of the inner sleeve (8) enters the motor flange (13), - At least partially filling (102) a stator space (6) between inner sleeve (8) and outer sleeve (11) with a first potting compound (22), - Arranging (103) the stator windings (35) and the iron return (36) in the stator space (6), in particular on an outer circumference of the inner sleeve (8), in the first potting compound (22), in particular which has not yet hardened, - Insertion (104) of the rotor (4) together with the rotor bearing means (9) into a rotor space (7) formed by the inner sleeve (8), so that a motor shaft section (31 ) of the rotor (4) protrudes from the housing (2) in the area of ​​the motor flange (13), - Arranging (105) a flushing flange (25), in particular at least partially in the inner sleeve (8), and at least one centner flange (21), in particular between the inner sleeve (8) and the outer sleeve (11), - Potting (106) the housing (2) at the second end side (20) with a second potting compound (23).

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