Optimized electric machine for driving rail vehicle

Abstract

The invention relates to an electric machine (1) for driving a rail vehicle. The invention relates to a motor comprising a closed active arrangement (3) which is arranged in a housing (2) and has a stator (4) and a rotor (5). An external cooling path (6) is provided for conducting cooling air drawn in from the environment (U) outside the closed active arrangement (3), and an internal cooling path (7) is provided for conducting cooling air inside the closed active arrangement (3). The rotor (5) has a number (N) of magnetic poles (P), each of which is formed by two permanent magnets (11) arranged in a V-shape. The rotor (5) has, for each magnetic pole (P), at least one cooling hole (13) axially penetrating the rotor lamination stack (8), through which cooling hole the internal cooling path (7) passes. According to the invention, the ratio of the intermediate angle (WZ) to the polar angle (WP) is in the range of 0.2 to 0.4, the polar angle (WP) representing the angular range covered by the permanent magnets (11) of one magnetic pole (P), and the intermediate angle (WZ) representing the angular range extending between the polar angles (WP) of adjacent magnetic poles (P). Furthermore, the ratio of the hole angle (WL) to the polar angle (WP) is in the range of 0.925 to 1.075, where the hole angle (WL) represents the angular range covered by the two cooling holes (13). As a result, optimization of the electric machine (1) in terms of energy efficiency, noise emission, production costs and in particular cooling behavior is provided for the operating condition behavior of the rail vehicle.

Description

[0001] The present invention relates to an electric motor for driving a rail vehicle according to the preamble of claim 1.

[0002] Motors used to drive vehicles must meet a wide variety of requirements. Optimizing the design of such motors for their respective operating conditions is a demanding task, especially since many different requirements can influence each other. To address this optimization task, several standard optimization methods are known, which determine the impact of each variable parameter on the requirements to be met through extensive simulation of machine design variations, thereby obtaining the optimal set of parameters for the motor designed for its operational behavior.

[0003] An optimized electric motor for driving hybrid vehicles, such as passenger cars, trucks, or buses, is known from patent document EP 3 542 445 B1. In this synchronous motor integrated into an internal combustion engine, a rotor uses two pole magnets arranged in a V-shape with each pole. The stator has axially extending stator slots that extend uniformly around the motor axis, through which stator windings pass. The rotor contains axially extending magnetic poles and is rotatably supported inside the stator about the motor axis. The pole magnets have rectangular cross-sections and are respectively disposed in axially extending pole openings. The number of holes in the motor is greater than or equal to 1, where the number of holes is understood as the number of stator slots divided by the number of phases and then divided by the number of rotor poles. Multi-objective optimization is used to optimize the motor's maximum torque, maximum power, short-circuit current, noise level, tone characteristics, cycle efficiency, material cost, losses, and torque ripple. Together with the outer pole cap and inner pole cap, as well as the specific pole magnet offset angle, there are two optimized parameter sets for the stator: the ratio of tooth height to yoke thickness, the ratio of tooth width to slot width at the tooth root and tooth tip, and the ratio of slot width at the tooth root to slot width at the tooth tip.

[0004] Motors of the aforementioned types used as traction or travel motors in rail vehicles must have a high power-to-weight ratio, while also possessing efficient and cost-effective cooling. Furthermore, manufacturing costs, overall weight, and noise emissions should be kept low. Given the very limited installation space in the bogie area of ​​rail vehicles, the motors must be as compact as possible. Based on the pre-defined operating conditions—the movement or travel process of the rail vehicle regarding starting, traveling, braking, and stopping—the motor operation requires a wide speed range and load range with high efficiency. Since a large number of transmission solutions can be used for rail vehicle traction drives, the transmission ratio of the corresponding transmission must also be considered to achieve optimal operating behavior. Especially in enclosed motors, multi-objective optimization requirements are high because these machine configurations, due to their enclosed active arrangement, place high demands on adequate cooling while simultaneously requiring high efficiency and quiet operation.

[0005] The technical problem to be solved by the present invention is to provide a motor of the above type, which is optimized in terms of energy efficiency, noise emissions, manufacturing costs, and especially cooling behavior according to its operating condition behavior.

[0006] This technical problem is solved by a motor having the features described in the feature portion of claim 1.

[0007] The aforementioned type of motor is configured and provided for driving rail vehicles, such as subway trains. The motor includes an active arrangement structure disposed within a motor housing and enclosed relative to the motor environment, the active arrangement structure having a stator and a rotor rotatable about a rotor axis relative to the stator. This enclosed structure protects the active arrangement structure from moisture and contaminants in the environment. The motor also includes an external cooling path for guiding cooling air drawn in from the environment outside the enclosed active arrangement structure, and an internal cooling path for guiding cooling air inside the enclosed active arrangement structure. The rotor has a hollow cylindrical rotor lamination assembly, which is torsionally connected to a rotor shaft rotatably supported in the housing and rotatable about a rotor axis. The rotor has a number (i.e., pole number) of magnetic poles, each consisting of two permanent magnets arranged in a V-shape and embedded in a magnetic pocket axially penetrating the rotor lamination assembly. Furthermore, the rotor has at least one cooling hole axially penetrating the rotor lamination assembly for each magnetic pole, through which the internal cooling path passes. Preferably, each magnetic pole is provided with two parallel cooling holes, for example, they can be arranged side by side and have the same radial distance from the rotor axis, and can have a circular or elongated hole cross-section.

[0008] According to the present invention, the ratio of the intermediate angle to the pole angle is in the range of 0.2 to 0.4. Here, the pole angle represents the angular range measured around the rotor axis covered by the permanent magnet of one pole. The intermediate angle represents the angular range extending between the pole angles of adjacent poles. Furthermore, according to the present invention, the ratio of the hole angle to the pole angle is in the range of 0.925 to 1.075, preferably 1. Here, the hole angle represents the angular range measured around the rotor axis covered by at least one cooling hole. Therefore, the hole angle of a pole is the minimum angular range covering one or more cooling holes of that pole. By selecting these parameters, a motor with high temperature distribution uniformity is provided while optimizing the aforementioned target characteristics.

[0009] In an advantageous embodiment of the motor of the present invention, the ratio of the magnet area to the rotor area is in the range of 0.05 to 0.25. The magnet area represents the sum of the cross-sectional areas of all permanent magnets in the rotor lamination assembly. The permanent magnets may have rectangular cross-sections, the area of ​​which is obtained by the product of the length and width of the cross-section. Since two permanent magnets are used for each pole, the cross-sectional area must be multiplied by twice the number of poles. The rotor area represents the area of ​​the annular rotor cross-section of the rotor lamination assembly. It is obtained by multiplying pi (π) by the difference between the square of the rotor's outer radius and the square of its inner radius.

[0010] In another advantageous embodiment of the motor according to the invention, the ratio of the hole area to the magnet area is in the range of 0.95 to 1.15, preferably about 1.05. Here, the hole area represents the sum of the cross-sectional areas of all cooling holes in the rotor lamination assembly.

[0011] In another advantageous embodiment of the motor according to the invention, the stator has a hollow cylindrical stator yoke with an outer casing and an inner casing, wherein the external cooling path passes through slotted cooling channels arranged on the inner side of the cylindrical casing of the housing, these cooling channels being defined by cooling sections of the outer casing of the stator yoke. The ratio of the cooling area to the casing area of ​​the outer casing of the stator yoke is in the range of 0.40 to 0.75. The cooling area represents the sum of the area of ​​all cooling sections.

[0012] In another advantageous embodiment of the motor according to the invention, cooling ribs extending into cooling channels are formed on the outer casing of the stator yoke, these cooling ribs forming enlarged cooling sections. The ratio of the enlarged cooling area to the total cooling area is in the range of 1.00 to 1.25. The enlarged cooling area represents the sum of the enlarged areas of all the enlarged cooling sections.

[0013] In another advantageous embodiment of the motor according to the invention, the ratio of rotor yoke height to pole height is in the range of 0.35 to 0.65. The rotor yoke height represents the radial width of the widest annulus extending around the rotor axis, radially located inside the permanent magnet and radially outside the cooling holes. The pole height represents the radial width of the narrowest annulus extending around the rotor axis where the permanent magnet is located.

[0014] In another advantageous embodiment of the motor according to the invention, the ratio of pole area to rotor area is in the range of 0.35 to 0.65. Here, pole area represents the area of ​​the narrowest annulus containing the permanent magnets, extending around the rotor axis.

[0015] In another advantageous embodiment of the motor according to the invention, the stator has stator teeth extending radially inward from the inner casing of the stator yoke, these stator teeth being spaced apart from each other by axially extending stator slots for receiving stator windings. The ratio of the stator yoke area to the stator area is in the range of 0.36 to 0.65. The stator yoke area represents the annular area of ​​a ring extending around the rotor axis, the outer radius of which corresponds to the radius of the outer casing, and the inner radius of which corresponds to the radius of the inner casing of the stator yoke. The stator area represents the annular area of ​​a ring extending around the rotor axis, the outer radius of which corresponds to the radius of the outer casing, and the inner radius of which corresponds to the radius of the inner casing of the stator yoke minus the tooth height of the stator teeth.

[0016] In another advantageous embodiment of the motor according to the invention, the ratio of stator tooth area to stator slot area is in the range of 0.95 to 1.10, preferably about 1.05. Herein, the stator tooth area represents the sum of the cross-sectional areas of all stator teeth. The stator slot area represents the sum of the cross-sectional areas of all stator slots.

[0017] In another advantageous embodiment of the motor according to the invention, the stator winding is led out from the stator slot at the end of the stator and introduced into the stator slot when forming the winding end. The ratio of the winding end extension length to the stator length is in the range of 0.10 to 0.40. The winding end extension length represents the length of the axial extension of the winding end beyond the stator end. The stator length represents the axial distance between the stator end ends, wherein the possible end plates of the stator lamination assembly are not included in the effective stator length.

[0018] In another advantageous embodiment of the motor according to the invention, the ratio of stator length to stator outer diameter is at least 0.75.

[0019] In another advantageous embodiment of the motor according to the invention, the number of poles is between 6 and 12, preferably 8.

[0020] Other features and advantages will become apparent from the following description of embodiments of the invention taken in conjunction with the accompanying drawings, in which...

[0021] Figure 1 The diagram shows a sector-shaped portion belonging to one magnetic pole in a cross-section of the motor according to the invention, and...

[0022] Figure 2 The diagram schematically shows a longitudinal section of the motor according to the invention, which is composed of two half-sections.

[0023] Figure 1 The diagram shows a sector-shaped portion of a cross-section of an eight-pole motor 1 according to the invention, the cross-section being transverse to the rotor axis R perpendicular to the plane of the drawing, wherein the sector-shaped portion corresponds to one of the eight magnetic poles P. Figure 2 A longitudinal section of the motor 1 according to the invention is shown, which is composed of two half-sections. Above the rotor axis R, a view according to... Figure 1 The half-section of the central section line IIa–IIa, and below the rotor axis R, shows the section according to... Figure 1 Half-section of the central section line IIb–IIb. According to Figure 1 and Figure 2 The motor 1 used to drive rail vehicles, such as subway trains, includes an active arrangement structure 3 disposed within a housing 2 of the motor 1 and enclosed relative to the environment U of the motor 1. This active arrangement structure has a stator 4 and a rotor 5 rotatable relative to the stator 4 about a rotor axis R. The enclosed structure protects the active arrangement structure 3 from moisture and contaminants in the environment U. The motor 1 also includes an external cooling path 6 and an internal cooling path 7. Cooling air drawn in from the environment U is guided outside the enclosed active arrangement structure 3 through the external cooling path, while the internal cooling path guides cooling air inside the enclosed active arrangement structure 3 to dissipate heat generated by the motor 1 during operation as a traction drive.

[0024] The rotor 5 of the motor 1 has a hollow cylindrical rotor lamination assembly 8, which is torsionally connected—for example, by thermal fitting—to a rotor shaft 10 rotatable about a rotor axis R. The rotor shaft 10 is rotatably supported in a housing 2, for example by rolling bearings 9. The rotor 5 here has a pole number N, which represents the number of magnetic poles P. In the illustrated embodiment, the pole number N=8, but depending on the rail vehicle to be driven, it could also be N=12, N=10, or N=6. Each magnetic pole P consists of two permanent magnets 11 arranged in a V-shape relative to each other. The rotor lamination assembly 8 is penetrated by axially extending magnet pockets 12, in which the permanent magnets 11 are embedded. The permanent magnets 11 have, for example, a rectangular cross-section, and are not shown for clarity. Figure 2 As shown in the figure. The gaps remaining in the magnet bag 12 after the permanent magnet 11 is inserted are filled with a filler material not shown. In addition, each magnetic pole P of the rotor has at least one cooling hole 13 that extends axially through the rotor lamination group 8, through which the internal cooling path 7 passes.

[0025] The stator 4 of the motor 1 has a hollow cylindrical stator yoke 14, which has an outer casing 15 and an inner casing 16. The stator yoke can also be designed as a laminated assembly. An external cooling path 6 passes through slotted cooling channels 18 arranged on the cylindrical inner side 17 of the housing 2. These cooling channels are defined by cooling sections 19 of the outer casing 15 of the stator yoke 14. Cooling ribs 20 extending into the cooling channels 18 can be formed on the outer casing 15 of the stator yoke 14. These cooling ribs form enlarged cooling sections 21 on the stator yoke 14 (relative to cooling sections 19 without cooling ribs 20). The stator 4 has stator teeth 22 extending radially inward from the inner casing 16 of the stator yoke 14. These stator teeth are spaced apart from each other by axially extending stator slots 23 for accommodating stator windings 24. Figure 2 The stator winding 24 is led out from the stator slot 23 at the end 25 of the stator 4 and reintroduced into the stator slot 23 with other angular offsets by forming the winding end.

[0026] The functional principle of the permanently magnet synchronous motor 1 constructed in this way is known, wherein the rotor shaft 10 drives the track wheels or wheelsets of a rail vehicle via a transmission device (not shown) and possibly coupling elements. During this process, heat is generated in the active arrangement structure 3, which must be dissipated by cooling air. Cooling air circulating in the internal cooling path 7 is supplied by an internal fan 27 driven by the rotor shaft 10. This cooling air, absorbing heat, flows through the first winding end of the stator winding 24, through cooling holes 13 in the rotor 5, and through the second winding end of the stator winding 24 opposite to the first winding end. From there, the cooling air, releasing heat, flows back through the axial channel 26 in the housing 2, where the internal cooling circuit is closed. Cooling air flowing through the external cooling path 6 is drawn from the environment U of the motor 1 through the housing opening by an external fan 28, which is also driven by the rotor shaft 10, and is guided along the cooling section 19 in the housing 2, along the cooling section 21 enlarged by the cooling ribs 20 in the illustrated embodiment, and blown back to the environment U through other different housing openings in order to transfer heat from the stator 4, the housing 2 and the internal cooling path 7 to the environment U.

[0027] Through the aforementioned multi-objective optimization, the geometric parameters of the motor 1 according to the invention, particularly the ratios of area, angle, or length, are optimized, thereby optimizing its energy efficiency, noise emissions, manufacturing costs, and especially its cooling behavior, taking into account the operating behavior of the rail vehicle to be driven. This avoids particularly hot locations within the motor 1 and achieves a temperature distribution that is as uniform as possible, with a small temperature deviation from the average value.

[0028] Optimal thermal behavior exists when the ratio of the intermediate angle WZ to the pole angle WP is in the range of 0.2 to 0.4, preferably about 0.3. Here, the pole angle WP represents the angular range measured around the rotor axis R covered by the permanent magnet 11 of a magnetic pole P. In other words, the pole angle WP is the minimum angular range of a permanent magnet 11 of a magnetic pole P. When the number of poles N=8, the pole angle WP can be between 34° and 35°. The intermediate angle WZ represents the angular range extending between the pole angles WP of adjacent magnetic poles P. When the number of poles N=8, the intermediate angle WZ can be between 10° and 11°. Furthermore, the optimized ratio of the hole angle WL to the pole angle WP is in the range of 0.925 to 1.075, preferably 1. In the illustrated embodiment, the hole angle WL represents the angular range measured around the rotor axis R covered by the two cooling holes 13. In other words, the hole angle WL is the minimum angular range of the cooling holes 13 accommodating the magnetic pole P. When the number of poles N=8, the aperture angle WL can be approximately 35°.

[0029] When the ratio of the magnet area AM to the rotor area AR is in the range of 0.05 to 0.25, preferably between 0.05 and 0.15, or particularly preferably between 0.10 and 0.11, further optimization of thermal behavior can be achieved. Here, the magnet area AM represents the sum of the cross-sectional areas A11 of all permanent magnets 11 in the rotor lamination group 8, i.e., AM = 2·N·A11. The rotor area AR represents the area of ​​the annular rotor cross-section of the rotor lamination group 8, which has an outer radius R8A and an inner radius R8I. Therefore, according to AR = π(R8A... 2 –R8I 2 )calculate.

[0030] Further optimization can be achieved when the ratio of the hole area AL to the magnet area AM is in the range of 0.95 to 1.15, preferably 1.05. Here, the hole area AL represents the sum of the cross-sectional areas A13 of all cooling holes 13 in the rotor lamination group 8, calculated in the illustrated embodiment according to AL = 2·N·A13.

[0031] When the ratio of the cooling area AK to the cover area A15 of the stator yoke 14 outer casing 15 is in the range of 0.40 to 0.75, preferably between 0.40 and 0.60, and particularly preferably about 0.45, further optimization of heat dissipation can be obtained. The cooling area represents the sum of the section areas A19 of all cooling sections 19. In the illustrated embodiment, the expanded cooling area AK+ by the formed cooling ribs 20 represents the sum of the expanded section areas A21 of all expanded cooling sections 21 of the stator yoke 14. In an optimized case, the ratio of the expanded cooling area AK+ to the cooling area AK is in the range of 1.00 to 1.25, preferably between 1.110 and 1.115.

[0032] When the ratio of rotor yoke height H to maximum height H11 is in the range of 0.35 to 0.65, preferably between 0.45 and 0.50, the motor 1 exhibits optimized thermal behavior. Here, rotor yoke height H represents the radial width of the widest annulus extending around the rotor axis R, radially located inside the permanent magnet 11 and radially outside the cooling holes 13. Maximum height H11 represents the radial width of the narrowest annulus extending around the rotor axis R where the permanent magnet 11 is located. Rotor yoke height H can, for example, be between 12 mm and 13 mm, and maximum height H11 can be between 26 mm and 27 mm.

[0033] When the ratio of pole area AP to rotor area AR is in the range of 0.35 to 0.65, preferably between 0.45 and 0.55, motor 1 exhibits further optimization. Here, pole area AP represents the area of ​​the narrowest annulus extending around the rotor axis R where the permanent magnet 11 is located. The outer radius of this annulus can be taken as the outer radius R8A of the rotor lamination group 8, and the radial width of this annulus corresponds to the pole height H11.

[0034] In addition to the parameters of rotor 5, the parameters of stator 4 also provide optimization possibilities regarding the cooling behavior of motor 1, which are determined through multi-objective optimization. Accordingly, the optimized ratio of stator yoke area A14 to stator area A4 is in the range of 0.35 to 0.65, preferably between 0.40 and 0.50, and particularly preferably about 0.45. Here, stator yoke area A14 represents the annular area of ​​a ring extending around rotor axis R, the outer radius of which corresponds to the radius R15 of outer casing 15, and the inner radius of which corresponds to the radius R16 of inner casing 16 of stator yoke 14. Stator area A4 represents the annular area of ​​a ring extending around rotor axis R, the outer radius of which corresponds to the radius R15 of outer casing 15, and the inner radius of which corresponds to the radius R16 of inner casing 16 of stator yoke 14 minus the tooth height H22 of stator teeth 22.

[0035] When the ratio of the stator tooth area AZ to the stator slot area AN is in the range of 0.95 to 1.10, preferably about 1.05, the motor 1 exhibits further optimization. Here, the stator tooth area AZ represents the sum of the cross-sectional areas A22 of all stator teeth 22 of the stator 4. The stator slot area AN represents the sum of the cross-sectional areas A23 of all stator slots 23 of the stator 4.

[0036] When the ratio of the winding end extension length L24 to the stator length L4 is in the range of 0.10 to 0.40, preferably between 0.20 and 0.30, and particularly preferably about 0.25, further optimization of heat dissipation can be obtained. The winding end extension length L24 represents the axial extension length of the stator winding 24 above the stator end 25 on the stator 4. The stator length L4 represents the axial distance between the opposite end 25s of the stator 4. When the stator length L4 is 300 mm, the winding end extension length L24 can be approximately 70 mm.

[0037] When the ratio of the stator length L4 to the outer diameter D4 of the stator 4, i.e., twice the radius R15 of the outer casing 15, is at least 0.75, preferably about 0.88, the motor 1 will also be optimized. The stator outer diameter D4 can be approximately 340 mm.

Claims

1. An electric motor (1) for driving rail vehicles, comprising: - An active arrangement structure (3) arranged within the housing (2) of the motor (1) and enclosed relative to the environment (U) of the motor (1), the active arrangement structure having a stator (4) and a rotor (5) rotatable relative to the stator (4) about a rotor axis (R), - An external cooling path (6) is used to guide cooling air drawn in from the environment (U) outside the enclosed active arrangement structure (3), and - Internal cooling path (7) for guiding cooling air within the enclosed active arrangement structure (3), -in, The rotor (5) has a hollow cylindrical rotor lamination assembly (8), which is torsionally connected to a rotor shaft (10) rotatably supported in the housing (2) and rotatable about the rotor axis (R). -The rotor (5) has magnetic poles (P) with a pole number (N), each magnetic pole (P) being composed of two permanent magnets (11) arranged in a V-shape and embedded in a magnet bag (12) that axially penetrates the rotor lamination assembly (8). -The rotor (5) has at least one cooling hole (13) axially penetrating the rotor lamination group (8) for each magnetic pole (P), and the internal cooling path (7) passes through the cooling hole. Its features are, - The ratio of the intermediate angle (WZ) to the polar angle (WP) is in the range of 0.2 to 0.

4. - Wherein, the pole angle (WP) represents the angular range covered by the permanent magnet (11) of a magnetic pole (P), measured around the rotor axis (R). - Wherein, the intermediate angle (WZ) represents the angular range extending between the pole angles (WP) of adjacent magnetic poles (P), and The ratio of the aperture angle (WL) to the polar angle (WP) is in the range of 0.925 to 1.

075. - Wherein, the hole angle (WL) represents the angular range covered by the at least one cooling hole (13) and measured around the rotor axis (R).

2. The motor (1) according to claim 1, -The ratio of magnet area (AM) to rotor area (AR) is in the range of 0.05 to 0.

25. -in, The magnet area (AM) represents the sum of the magnet cross-sectional areas (A11) of all permanent magnets (11) in the rotor lamination group (8), and - Wherein, the rotor area (AR) represents the area of ​​the annular rotor cross section (A8) of the rotor lamination group (8).

3. The motor (1) according to claim 2, -The ratio of aperture area (AL) to magnet area (AM) is in the range of 0.95 to 1.

15. -in, The hole area (AL) represents the sum of the cross-sectional areas (A13) of all the cooling holes (13) of the rotor lamination group (8).

4. The motor (1) according to any one of claims 1 to 3, -The stator (4) has a hollow cylindrical stator yoke (14) with an outer shell (15) and an inner shell (16), and -in, The external cooling path (6) passes through the grooved cooling channels (18) arranged on the cylindrical inner side (17) of the housing (2), and these cooling channels are respectively defined by the cooling sections (19) of the outer shell (15) of the stator yoke (14). -The ratio of the cooling area (AK) to the casing area (A15) of the outer casing (15) of the stator yoke (14) is in the range of 0.40 to 0.

75. - Wherein, the cooling area (AK) represents the sum of the area (A19) of all cooling sections (19).

5. The motor (1) according to claim 4, - In this structure, cooling ribs (20) extending into the cooling channels (18) are formed on the outer shell (15) of the stator yoke (14), and these cooling ribs constitute an enlarged cooling section (21). -in, The ratio of the increased cooling area (AM+) to the cooling area (AM) is in the range of 1.00 to 1.

25. -wherein, the The enlarged cooling area (AM+) represents the sum of the enlarged section areas (A21) of all the enlarged cooling sections (21).

6. The motor (1) according to any one of claims 1 to 5, -The ratio of rotor yoke height (H) to maximum height (H11) is in the range of 0.35 to 0.

65. -in, The rotor yoke height (H) represents the radial width of the widest annulus extending around the rotor axis (R), radially located inside the permanent magnet (11) and radially outside the cooling hole (13). - Wherein, the extreme height (H11) represents the radial ring width of the narrowest ring within which the permanent magnet (11) extends around the rotor axis (R).

7. The motor (1) according to any one of claims 2 to 6, -in, The ratio of pole area (AP) to rotor area (AR) is in the range of 0.35 to 0.

65. - Wherein, the pole area (AP) represents the ring area of ​​the narrowest ring within which the permanent magnet (11) extends around the rotor axis (R).

8. The motor (1) according to any one of claims 1 to 7, -The stator (4) has stator teeth (22) extending radially inward from the inner casing (16) of the stator yoke (14), and these stator teeth are spaced apart from each other by stator slots (23) extending axially for accommodating stator windings (24). -in, The ratio of the stator yoke area (A14) to the stator area (A4) is in the range of 0.36 to 0.

65. - Wherein, the stator yoke area (A14) represents the annular area of ​​a ring extending around the rotor axis (R), the outer radius of which corresponds to the radius (R15) of the outer casing (15), and the inner radius of which corresponds to the radius (R16) of the inner casing (16) of the stator yoke (14). - Wherein, the stator area (A4) represents the annular area of ​​a ring extending around the rotor axis (R), the outer radius of which corresponds to the radius (R15) of the outer casing (15), and the inner radius of which corresponds to the radius (R16) of the inner casing (16) of the stator yoke (14) minus the tooth height (H22) of the stator tooth (22).

9. The motor (1) according to claim 8, -The ratio of stator tooth area (AZ) to stator slot area (AN) is in the range of 0.95 to 1.

10. -in, The stator tooth area (AZ) represents the sum of the cross-sectional areas (A22) of all stator teeth (22), and - Wherein, the stator slot area (AN) represents the sum of the slot cross-sectional areas (A23) of all stator slots (23).

10. The motor (1) according to claim 8 or 9, - wherein the stator winding (24) is drawn out from the stator slot (23) at the end (25) of the stator (4) and introduced into the stator slot (23) in the case of forming the winding end. -in, The ratio of the winding end extension length (L24) to the stator length (L4) is in the range of 0.10 to 0.

40. - Wherein, the winding end extension length (L24) represents the length of the axial extension of the winding end above the end face (25) of the stator (4), and - Wherein, the stator length (L4) represents the axial distance between the end faces (25) of the stator (4).

11. The motor (1) according to any one of claims 8 to 10, - wherein the ratio of the stator length (L4) to the outer diameter (D4) of the stator (4) is at least 0.

75.

12. The motor (1) according to any one of claims 1 to 11, -in, The number of poles (N) is between 6 and 12, preferably 8.

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