Stator assembly

Abstract

A stator assembly for a brushless permanent magnet motor includes a stator core, a plurality of coils wound around the stator core, and a plurality of terminal connectors to which the plurality of coils are connected. A first subset of the plurality of terminal connectors is located at a first end of the stator assembly, and a second subset of the plurality of terminal connectors different from the first subset of the plurality of terminal connectors is located at a second end of the stator assembly opposite the first end of the stator assembly.

Description

Technical Field

[0001] The present invention relates to a stator assembly for a brushless permanent magnet motor and to a brushless permanent magnet motor comprising the stator assembly. Background Art

[0002] It is often desirable to improve electric motors, such as brushless motors, in a variety of ways. For example, improvements may be desired in size, weight, power density, manufacturing cost, efficiency, reliability, and noise. Summary of the Invention

[0003] According to a first aspect of the present invention, a stator assembly for a brushless permanent magnet motor is provided, the stator assembly comprising: a stator core; a plurality of coils wound around the stator core; and a plurality of terminal connectors, the plurality of coils being connected to the plurality of terminal connectors; wherein a first subset of the plurality of terminal connectors is located at a first end of the stator assembly, and a second subset of the plurality of terminal connectors is different from the first subset of the plurality of terminal connectors and is located at a second end of the stator assembly opposite to the first end of the stator assembly.

[0004] Positioning the terminal connectors at opposite ends of the stator assembly can enable the stator assembly to have smaller radial and / or axial dimensions compared to a stator assembly in which the terminal connectors are located at a single end of the stator assembly. For example, where the terminal connectors are located at a single end of the stator assembly, a larger radial and / or axial dimension of the stator assembly may be required in order to maintain sufficient creepage and clearance distances between the terminal connectors. In contrast, by positioning the first and second subsets of terminal connectors at opposite ends of the stator assembly, such an increase in radial and / or axial dimension may not be required to accommodate the same number of terminal connectors in the stator assembly of the present invention.

[0005] By minimizing the radial and / or axial dimensions of the stator assembly, the size of the brushless permanent magnet motor including the stator assembly can be minimized, which can provide a minimized packaging volume for the brushless permanent magnet motor within an appliance.

[0006] Furthermore, positioning the terminal connections at opposite ends of the stator assembly may facilitate manufacture of the stator assembly, such as by providing more space for accessing the terminal connections compared to an arrangement where all terminal connections are located at a single end of the stator assembly.

[0007] The first and second subsets of the plurality of terminal connectors may comprise non-empty subsets of the plurality of terminal connectors, eg, such that there is at least one terminal connector in each of the respective first and second subsets of the plurality of terminal connectors.

[0008] The first subset of the plurality of terminal connectors may be smaller than the second subset of the plurality of terminal connectors. For example, the first subset of the plurality of terminal connectors may have a smaller cardinality than the second subset of the plurality of terminal connectors.

[0009] The first subset of the plurality of terminal connectors may include three terminal connectors, such as exactly three terminal connectors.The second subset of the plurality of terminal connectors may include six terminal connectors, such as exactly six terminal connectors.

[0010] The plurality of coils may be connected to the plurality of terminal connections such that the stator assembly comprises a three-phase stator assembly for a three-phase brushless permanent magnet motor. Positioning the terminal connections at opposite ends of the stator assembly may be particularly suitable for a three-phase stator assembly.

[0011] Multiple coils can be connected in a star configuration via multiple terminal connections. Positioning the terminal connections at opposite ends of the stator assembly can be particularly suitable for the star configuration of the coils, for example by enabling the neutral connection of the star configuration to be positioned at the end of the stator assembly opposite the live connections. The neutral connection can be at a different potential than the potential of the three phases of the star configuration. Spatially separating the neutral connection from the three phases can reduce the number of potentials in close proximity that must be isolated from each other. Thus, having the neutral connection at the end of the motor opposite the three-phase connection can reduce the number of different potentials that must be isolated in a relatively small space.

[0012] Multiple coils can be connected in a parallel star configuration via multiple terminal connectors. For example, where there are multiple coils per phase, coils of the same phase can be electrically connected in parallel with each other. Positioning the terminal connectors at opposite ends of the stator assembly can be particularly suitable for a parallel star configuration of the coils. For example, separating the terminal connectors in this manner can provide sufficient spacing between the terminal connectors to allow a minimum number of electrical connections to be made between the terminal connectors to provide a parallel star configuration of the coils. Providing a minimum number of terminal connectors can reduce the number of manufacturing operations required to assemble the stator assembly, thereby reducing manufacturing time or cost, and can also minimize the number of parts, which can result in a reduced risk of failure.

[0013] The first subset of terminal connectors may include a neutral terminal connector, e.g., only a neutral terminal connector. This may enable the neutral terminal connector to be separated from the live terminal connector and may facilitate connection of the neutral terminal connector, e.g., by providing a clear line of sight between the neutral terminal connectors, enabling use of a relatively simple connection mechanism.

[0014] The first subset of terminal connections may be connected via a common neutral busbar, such as a single common neutral busbar. This may provide a relatively simple connection mechanism. Using a single common neutral busbar may reduce the number of components, which may reduce cost and / or reduce the risk of failure compared to an arrangement with multiple neutral busbars.

[0015] The second subset of terminal connectors may include live terminal connectors, e.g., only live terminal connectors. This may enable the live terminal connectors to be separated from the neutral terminal connectors and may facilitate connection of the live terminal connectors, e.g., by providing a clear line of sight between the live terminal connectors, enabling maximum contact of a manufacturing tool head to create a connection.

[0016] The second subset of terminal connectors may include multiple pairs of terminal connectors, each terminal connector within a pair being connected together by a live busbar. The use of a busbar may provide a simpler connection mechanism than, for example, using tracks on a PCB to connect the live terminal connectors, and may provide reduced cost and / or environmental benefits when compared to using tracks on a PCB.

[0017] Each pair of terminal connections may correspond to a pair of coils, such as a pair of coils of the same phase.

[0018] Each live busbar may have substantially the same form, such as substantially the same shape and / or substantially the same size. This may provide manufacturing convenience and reduce manufacturing costs compared to arrangements requiring busbars of multiple forms, for example.

[0019] Each live busbar may extend substantially 180 degrees around the circumference of the stator assembly, for example with coils of the same phase positioned diametrically opposite one another in the stator assembly.

[0020] Each busbar may include a live input connection located substantially at the midpoint of the busbar, between the corresponding live terminal connections. This may reduce the risk of unbalanced currents flowing between coils of the same phase, for example where coils of the same phase are connected in parallel, which may otherwise result in recirculating currents that do not contribute to the generation of torque and may result in radial loads on a rotor assembly that the stator assembly is used to drive in use.

[0021] The stator assembly may include a carrier to which the live busbars are mounted. This may provide increased stability during manufacture compared to, for example, a stator assembly in which no such carrier is present.

[0022] The plurality of terminal connectors may include pins extending axially from respective first and second ends of the stator assembly. Terminal connectors extending axially from the first and second ends of the stator assembly can minimize the radial footprint of the stator assembly, compared to, for example, terminal pins extending radially outward from the stator assembly. This can minimize the stator assembly's package volume in the radial direction. The terminal connectors may not extend radially outward further than the outer periphery of the stator core and / or the outer periphery of the coils.

[0023] The first subset of the plurality of terminal connections may be substantially evenly spaced around a perimeter of the first end of the stator assembly. This may facilitate connection of the first subset of the plurality of terminal connections.

[0024] The second subset of the plurality of terminal connectors may be substantially evenly spaced around the perimeter of the second end of the stator assembly. This may facilitate connection of the second subset of the plurality of terminal connectors while maximizing the distance between the terminal connectors from a creepage and / or clearance distance perspective.

[0025] The stator assembly can include a plurality of stator core assemblies, each stator core assembly including stator core segments. By providing a segmented stator core, winding the coils around the stator core can be reduced in cost and / or complexity compared to, for example, a winding process for a fully annular stator core. Furthermore, a higher copper fill factor can be achieved when compared to a winding process for a fully annular stator core.

[0026] The stator assembly can include three stator core assemblies, for example, exactly three stator core assemblies. This can provide for easier winding of coils around the stator core segments, compared to, for example, an arrangement using only two stator core assemblies and, therefore, two stator core segments. For example, an arrangement having only two stator core segments can result in the stator core segments each spanning approximately 180 degrees, which can provide a winding machine with reduced access to the interior of the bend defined by the stator core segments when compared, for example, to a bend of shorter arc length. This can be particularly the case when each stator core assembly has exactly two coils.

[0027] Furthermore, for a three-phase motor, having a multiple of three stator core assemblies can maintain impedance and / or current balance between the three phases. Three stator core assemblies is the minimum number of stator core assemblies that can achieve this, and when compared to a higher multiple of three stator core assemblies, three stator core assemblies can minimize any increase in magnetic resistance in the magnetic circuit due to interfaces between the stator core assemblies.

[0028] Each stator core assembly includes a bobbin mounted to a corresponding stator core segment, at least one terminal connector from a first subset of the plurality of terminal connectors is mounted to each bobbin, and at least two terminal connectors from a second subset of the plurality of terminal connectors are mounted to each bobbin. In this manner, the terminal connectors can be substantially evenly distributed between the stator core assemblies.

[0029] Each stator core assembly may include two coils, and the two coils may be wound in opposite directions. Because each stator core assembly includes the same number of coils, with one coil wound in each direction, e.g., left-handed or right-handed, the stator core assemblies may be substantially similar in form, which may reduce the cost and / or complexity of the stator assembly manufacturing process compared to, for example, stator assemblies using stator core assemblies of different forms.

[0030] Both coils can be wound using a single wire, for example using a continuous winding process, which can reduce the manufacturing cost and complexity of the stator assembly compared to, for example, a stator assembly that uses a separate wire to wind each coil.

[0031] Each stator core assembly may comprise substantially the same form. This may reduce the cost and complexity of manufacturing the stator assembly compared to, for example, a stator assembly using stator core assemblies of different forms.

[0032] The stator assembly may have an outer diameter of no greater than 40 mm, e.g., no greater than 35 mm, no greater than 30 mm, no greater than 25 mm, or no greater than 20 mm. Positioning the terminal connections at opposite ends of the stator assembly may achieve such a size of the stator assembly while maximizing the available distance for creepage and / or clearance distances of the plurality of terminal connections.

[0033] The stator assembly may be overmolded, for example, with an electrically insulating material such as a plastic material. This may allow the terminal connections to the first subset and / or the second subset to be closer together than in an arrangement without such overmolding. The plastic material may include a filler, for example, a filler intended to enhance thermal conductivity compared to the plastic material alone.

[0034] A second aspect of the present invention provides a brushless permanent magnet motor comprising a stator assembly according to the first aspect of the present invention.

[0035] The plurality of coils, when energized, may generate a magnetic field that interacts with permanent magnets of a rotor assembly of the brushless permanent magnet motor to rotate the rotor assembly relative to the stator assembly.

[0036] The brushless permanent magnet motor may be configured to operate at approximately 400 V, for example where the coils are configured to receive a DC link voltage of approximately 400 V.

[0037] According to a third aspect of the present invention, there is provided a hair care appliance comprising a brushless permanent magnet motor according to the second aspect of the present invention.

[0038] According to a fourth aspect of the present invention, there is provided a vacuum cleaner comprising the brushless permanent magnet motor according to the second aspect of the present invention.

[0039] Where appropriate, optional features of one aspect of the invention may be equally applicable to other aspects of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 is a perspective view of the stator assembly;

[0041] Figure 2 yes Figure 1 Exploded view of the stator assembly;

[0042] Figure 3 yes Figure 1 a perspective view of a stator core assembly of a stator assembly;

[0043] Figure 4 yes Figure 3 An exploded view of the stator core assembly;

[0044] Figure 5 yes Figure 1 a perspective view of a first busbar assembly of a stator assembly;

[0045] Figure 6 yes Figure 5 A perspective view of a live busbar of a first busbar assembly;

[0046] Figure 7 It is a perspective view of the neutral busbar;

[0047] Figure 8 is included Figure 1 Schematic diagram of a brushless permanent magnet motor having a rotor assembly;

[0048] Figure 9 is included Figure 6 A schematic diagram of a brushless permanent magnet motor of a vacuum cleaner; and

[0049] Figure 10 is included Figure 1 Schematic diagram of a hair care appliance with a brushless permanent magnet motor. DETAILED DESCRIPTION

[0050] The stator assembly 10 is Figure 1 and Figure 2 1 , and includes a first stator core assembly 12 , a second stator core assembly 14 , and a third stator core assembly 16 , as well as a first bus bar assembly 18 and a second bus bar assembly 20 .

[0051] The first stator core assembly is as follows Figure 3 and Figure 4 Each of the first stator core assembly 12, the second stator core assembly 14, and the third stator core assembly 16 has substantially the same form, and therefore, for the sake of brevity, the second stator core assembly 14 and the third stator core assembly 16 will not be described in detail herein. It should be understood that the same reference numerals used for features of the first stator core assembly 12 may be used for corresponding features of the second stator core assembly 14 and the third stator core assembly 16.

[0052] The first stator core assembly 12 includes a stator core segment 22 , a bobbin 24 , first 26 , second 28 , and third 30 terminal connections, and a first coil 32 and a second coil 34 .

[0053] The stator core segments 22 are formed from a stack of steel laminations (not shown) and are generally arcuate, with a height greater than both length and width. The stator core segments 22 span an arc length of approximately 120 degrees. The circumferential end faces of the stator core segments 22 are generally planar in form.

[0054] The bobbin 24 is formed of a plastic material and is overmolded to the stator core segment 22. The bobbin 24 includes a connection recess 36, a window 38, and a connection structure 40. The connection recess 36 is generally cylindrical in form and is shaped and sized to receive the corresponding first to third terminal connectors 26-30. The window 38 is generally elongated and rectangular in cross-section and provides a line of sight to the radially outer surface of the stator core segment 22. The window 38 enables appropriate magnets to hold the stator core segment 22 in place during assembly of the first stator core assembly 12. The connection structure 40 includes appropriate protrusions and / or recesses that interact with corresponding recesses and / or protrusions of the second stator core assembly 14 and the third stator core assembly 16 to hold the stator core assemblies 12, 14, 16 relative to each other.

[0055] The first through third terminal connectors 26-30 have substantially the same form and are typically elongated pins formed of a conductive material with a square cross-sectional shape. The first and second terminal connectors 26, 28 are inserted into corresponding connection recesses 36 by a push fit and extend axially outward from a first end 42 of the first stator core assembly 12. The third terminal connector 30 is inserted into the corresponding connection recess 36 and extends axially outward from a second end 44 of the first stator core assembly 12 opposite the first end 42 of the first stator core assembly 12.

[0056] The first and second coils 32, 34 are formed from multiple turns of copper wire and are wound around the bobbin 24 such that the first and second coils 32, 34 cover both the radially inner and radially outer surfaces of the stator core segments 22. The stator assembly 10 is a slotless stator assembly. For clarity, the first and second coils 32, 34 are shown in block form, so that the individual turns are not visible in the figure. The first and second coils 32, 34 are formed from a single piece of copper wire, allowing them to be wound using a continuous winding process. For example, the first coil 32, located at the first terminal connection 26, is wound around the bobbin 24, and thus around the stator core segments 22, and is tied at the third terminal connection 30. The second coil 32 then begins at the third terminal connection 30, is wound around the bobbin 24, and thus around the stator core segments 22, and is tied at the second terminal connection 28. The first coil 32 and the second coil 34 are wound in opposite directions, wherein one of the first coil 32 and the second coil 34 is wound in a right-handed manner, and the other of the second coil 34 and the first coil 32 is wound in a left-handed manner.

[0057] Collectively, the first, second, and third stator core assemblies 12, 14, and 16, when connected together, define an annular space having a central bore 46 for receiving the rotor assembly, wherein the stator assembly 10 has a diameter of no greater than 40 mm. When connected together, the generally circumferential surfaces of the stator core segments 22 substantially contact one another, such that a generally annular stator core is formed by the stator core segments 22. The first and second terminal connectors 26, 28 of each stator core assembly 12, 14, 16 form a first subset of terminal connectors located at a first end 48 of the stator assembly 10, and the third terminal connector 30 forms a second subset of terminal connectors located at a second end 50 of the stator assembly 10.

[0058] The first and second terminal connections 26 , 28 are evenly spaced around the circumference of the first end 48 of the stator assembly 10 , while the third terminal connections 30 are evenly spaced around the circumference of the second end 50 of the stator assembly 10 .

[0059] The first busbar assembly 18 is located at a first end 48 of the stator assembly 10 and is Figure 5 The first busbar assembly 18 includes a carrier 52 and three live busbars 54 .

[0060] The carrier 52 is generally annular in form and is molded from a plastic material. The carrier 52 includes three channels 56 and three heat stakes 58. Each channel 56 has a substantially identical form, is formed on the radially outer surface of the carrier 52, and has a central portion 60, an upper portion 62, and a lower portion 64. The central portion 60 extends axially along the height of the carrier 52, while the upper portion 62 extends circumferentially from the central portion 60 in a first direction, and the lower portion 64 extends circumferentially from the central portion 60 in a second direction opposite the first direction. The upper portion 62 of one channel 56 overlaps the lower portion 64 of an adjacent channel 56 on the carrier 52. Each heat stake 58 is located in the corresponding central portion 60 of the channel 56.

[0061] Live bus 54 Figure 6 5. The live busbar 54 is formed of an electrically conductive material and includes a central portion 66, an upper portion 68, and a lower portion 70. The central portion 66 extends axially in a height direction, while the upper portion 68 extends circumferentially from the central portion 66 in a first direction, and the lower portion 70 extends circumferentially from the central portion 66 in a second direction opposite the first direction. The central portion 66 defines a connection between the stator assembly 10 and an inverter (not shown), such as a live connection of the stator assembly that can receive a voltage during use. The central portion 66 includes a hole 72 for receiving a corresponding heat stake 58 of the carrier 52.

[0062] Each of the upper portion 68 and the lower portion 70 includes a connecting arm 74 extending in a direction parallel to the height of the middle portion 66. The connecting arms 74 are generally evenly spaced apart from the middle portion 66. The connecting arms 74 are welded at the first end 48 of the stator assembly 10 to the first terminal connection 26 and the second terminal connection 28 of each stator core assembly 12, 14, 16. Each live bus bar 54 is thereby connected to two coils of the stator assembly.

[0063] The second busbar assembly 20 is located at the second end 50 of the stator assembly 10 and is Figure 7 16 . The second busbar assembly 20 includes a single neutral busbar having a main body 76 and three connecting arms 78. The main body 76 is arcuate, and the three connecting arms 78 extend from the main body 76. The connecting arms 78 are welded to the third terminal connection 30 of each stator core assembly 12, 14, 16 at the second end 50 of the stator assembly 10. Assuming that the first coil 32 and the second coil 34 of each stator core assembly 12, 14, 16 are connected to the third terminal connection 30 of that particular stator core assembly 12, 14, 16, and that a single neutral busbar is used to connect the third terminal connections 30 together, each first coil 32 and second coil 34 of the stator assembly is connected together by the second busbar assembly 20.

[0064] In the manner described above, coils 32 , 34 and first and second busbar assemblies 18 , 20 define a three-phase parallel star connection with first and second terminal connections 26 , 28 serving as live connections and third terminal connection 30 serving as neutral connection.

[0065] Positioning the first and second terminal connections 26, 28 at the opposite end of the stator assembly 10 from the third terminal connection 30 can enable the stator assembly 10 to have a smaller radial and / or axial dimension than a stator assembly having terminal connections located at a single end of the stator assembly. By minimizing the radial and / or axial dimension of the stator assembly, the size of the brushless permanent magnet motor including the stator assembly 10 can be minimized, which can provide a minimized packaging volume for the brushless permanent magnet motor within an appliance.

[0066] Furthermore, positioning the terminal connectors at opposite ends of the stator assembly 10 in the manner described above may facilitate manufacture of the stator assembly 10 by providing more space for accessing the terminal connectors compared to an arrangement where all terminal connectors are located at a single end of the stator assembly 10 .

[0067] The manufacture of the stator assembly 10 can be further facilitated by using three stator core segments 22, each of which spans an arc length of approximately 120 degrees. In particular, segmenting the stator core can enable the stator core segments 22 to be more linear than would be the case if a smaller number of segments were used to form an annular stator core. This can facilitate the formation of the laminations that form the stator core segments 22, for example by enabling an increased number of laminations to be formed from a single piece of material, thereby reducing material waste and cost.

[0068] Furthermore, a toroidal core or two-part core with each segment spanning an arc length of 180 degrees provides a winding machine with reduced access to the interior of the bend defined by the stator core segments when compared to, for example, a bend with a shorter arc length. The shorter arc length stator core segments can enable the use of an easier and / or less expensive winding process.

[0069] In use, the stator assembly 10 is mated with the rotor assembly 100 to form a brushless permanent magnet motor 102, such as Figure 8 The rotor assembly 102 includes a shaft 104 and permanent magnets 106 mounted to the shaft 104. When the coils 32, 34 are driven at an appropriate voltage (here up to about 400 V), the stator assembly 10 generates a magnetic field that interacts with the permanent magnets 106 to rotate the rotor assembly 100.

[0070] exist Figure 9 A vacuum cleaner 200 comprising a brushless permanent magnet motor 102 is schematically shown in FIG.

[0071] exist Figure 10A hair care appliance 300 including a brushless permanent magnet motor 102 is schematically shown in FIG.

Claims

1. A stator assembly for a brushless permanent magnet motor, the stator assembly comprising: stator core; a plurality of coils wound around the stator core; and a plurality of terminal connectors to which the plurality of coils are connected; wherein a first subset of the plurality of terminal connectors is located at a first end of the stator assembly, and a second subset of the plurality of terminal connectors is different from the first subset of the plurality of terminal connectors and is located at a second end of the stator assembly opposite the first end of the stator assembly.

2. The stator assembly according to claim 1, wherein: The plurality of coils are connected to the plurality of terminal connections such that the stator assembly comprises a three-phase stator assembly for a three-phase brushless permanent magnet motor.

3. The stator assembly according to claim 1 or 2, wherein: The plurality of coils are connected in a star configuration via the plurality of terminal connectors.

4. A stator assembly according to any one of the preceding claims, wherein: The plurality of coils are connected in a parallel star configuration via the plurality of terminal connectors.

5. The stator assembly according to claim 3 or 4, wherein: The first subset of the terminal connections includes a neutral terminal connection.

6. The stator assembly according to claim 5, wherein: The first subset of the terminal connections are connected by a common neutral busbar.

7. The stator assembly according to any one of claims 3 to 6, wherein: The first subset of the terminal connectors includes exactly three terminal connectors.

8. The stator assembly according to any one of claims 3 to 7, wherein: The second subset of the terminal connections includes live terminal connections.

9. The stator assembly according to claim 8, wherein: The second subset of terminal connectors includes a plurality of pairs of terminal connectors, each terminal connector within a pair being connected together by a live busbar.

10. The stator assembly according to claim 9, wherein: Each live busbar has substantially the same form.

11. The stator assembly according to claim 9 or 10, wherein: The stator assembly includes a carrier to which the live busbars are mounted.

12. A stator assembly according to any one of the preceding claims, wherein: The plurality of terminal connections include pins extending axially from respective first and second ends of the stator assembly.

13. A stator assembly according to any one of the preceding claims, wherein: The first subset of the plurality of terminal connections is substantially evenly spaced around a perimeter of the first end of the stator assembly.

14. A stator assembly according to any one of the preceding claims, wherein: The second subset of the plurality of terminal connections is substantially evenly spaced around a perimeter of the second end of the stator assembly.

15. A stator assembly according to any one of the preceding claims, wherein: The stator assembly includes a plurality of stator core assemblies, each stator core assembly including stator core segments.

16. A stator assembly according to any one of the preceding claims, wherein: The stator assembly includes three stator core assemblies.

17. The stator assembly according to claim 15 or 16, wherein: Each stator core assembly includes a bobbin mounted to a corresponding stator core segment, at least one terminal connector of the first subset of the plurality of terminal connectors mounted to each bobbin, and at least two terminal connectors of the second subset of the plurality of terminal connectors mounted to each bobbin.

18. The stator assembly according to any one of claims 15 to 17, wherein: Each stator core assembly includes two coils, and the two coils are wound in opposite directions.

19. The stator assembly according to any one of claims 15 to 18, wherein: The two coils are wound using a single wire.

20. The stator assembly according to any one of claims 15 to 19, wherein: Each stator core assembly comprises substantially the same form.

21. A stator assembly according to any one of the preceding claims, wherein: The stator assembly has an outer diameter of no greater than 40 mm.

22. A stator assembly according to any one of the preceding claims, wherein: The stator assembly is overmolded with a plastic material.

23. A brushless permanent magnet electric machine comprising a stator assembly according to any one of the preceding claims.

24. A hair care appliance comprising the brushless permanent magnet motor according to claim 23.

25. A vacuum cleaner comprising the brushless permanent magnet motor according to claim 23.

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