Axial flux machine for an electric power tool and electric power tool having an axial flux machine

Abstract

The invention relates to an axial flux machine (10), in particular a single-sided axial flux motor, for an electrical machining tool (34), comprising a machine shaft (12), a disk-shaped stator (20), and a disk-shaped rotor (14) arranged adjacent to the stator (20) in the axial direction (A) of the machine shaft (12), the machine shaft (12), in particular a motor shaft, wherein the stator (20) is designed as a winding carrier (22) for at least one stator winding (24), and the rotor (14) connected to the machine shaft (12) in a rotationally fixed manner can be set into rotational motion relative to the stator (20). It is proposed that the stator (20) of the axial flux machine (10) consists of a combination of a composite material, in particular a fiber-plastic composite, and a soft magnetic field. The invention also relates to an electrical machining tool (34) having the axial flux machine (10) according to the invention.

Description

Technical Field

[0001] The present invention relates to an axial flux motor for an electrical discharge machining (EDM) appliance, particularly a single-sided axial flux motor, and an EDM appliance having an axial flux motor, according to the class of the independent claims. Background Technology

[0002] Compared to conventional electric motors with radial flux direction, axial flux motors offer advantages such as high efficiency and significantly reduced structural length. Furthermore, they achieve higher torque density, or power density, within the same outer diameter. These improvements are particularly attributable to a larger air gap area within a similar structural volume. Additionally, the smaller iron volume of the rotating components results in higher efficiency over a wider speed range.

[0003] The construction of the stator in an axial flux engine is relatively expensive due to the required 3D flux guidance. Typically, the slots of the lamination assembly must be punched before the stator winding process. Furthermore, the individual laminations have the disadvantage that the pole shoes only achieve tangential protrusions and cannot be externally wound with stator teeth that have protruding pole shoes, resulting in a small fill factor in the stator windings and consequently reduced efficiency.

[0004] An axial flux mechanism is known from DE 10 2015 223 766 A1, which has bent and wound laminations as winding carriers. The stator of the axial flux mechanism has a carrier structure made of sintered soft magnetic material and inserts constructed as laminations. The inserts are attached to the carrier structure by form-locking and / or force-locking and at least partially form the pole shoes of the axial flux mechanism. The laminations are formed on a single lamination by means of individual, stacked layers made of soft iron. The individual laminations are attached to each other in a manner that is electrically insulated from their respective adjacent laminations.

[0005] Alternatively, the stator of an axial flux transfer motor is also constructed entirely of composite material (soft magnetic composites, SMC). SMC material consists of high-purity iron powder with a specialized surface coating on each individual particle. This electrically insulating surface ensures high resistance even after extrusion and heat treatment, which in turn minimizes or eliminates eddy current losses. SMC material is known to those skilled in the art, and its composition will not be discussed further here. However, stators made of composite materials are particularly fragile or impact-sensitive and have a lower permeability compared to soft magnetic sheets. However, for axial flux transfer motors, especially those used in electrical discharge machining (EDM) tools, and particularly in power tools, high insensitivity to vibration and shock is particularly important. On the other hand, the use of composite materials cannot be omitted due to the torque density required by axial flux transfer motors. Summary of the Invention

[0006] Therefore, the object of the present invention is to provide a stator for an axial flux machine that is particularly insensitive to collisions compared to the prior art, while achieving a high torque density for the axial flux machine.

[0007] The present invention relates to an axial flux motor for electrical discharge machining (EDM) tools, particularly a single-sided axial flux motor, the axial flux motor having a machine shaft, a disc-shaped stator and a disc-shaped rotor arranged adjacent to the stator in the axial direction of the machine shaft, the machine shaft being particularly a motor shaft, wherein the stator is configured as a winding carrier for at least one stator winding, and the rotor, which is torsionally connected to the machine shaft, is capable of rotational motion relative to the stator.

[0008] To address the proposed task setting: the stator is constructed from a combination of composite materials and soft magnets, particularly fiber-reinforced plastic composites. A significant advantage over prior art axial flux linkages is that this provides an axial flux linkage that is extremely resistant to mechanical stress and simultaneously exhibits excellent performance and efficiency, or a high-torque axial flux motor. This enables its use in electrical discharge machining (EDM) appliances that are, on the one hand, particularly robust to impacts and vibrations, and on the other hand, must provide very high electromagnetic power over extended periods of use. Therefore, the present invention also relates to an EDM appliance, particularly a power tool, having an axial flux linkage according to the invention, particularly an axial flux motor according to the invention.

[0009] In the context of this invention, electrical discharge machining (EDM) appliances should be understood in particular as battery-powered or grid-connected power tools used for machining workpieces using electrically driven insert tools. Here, EDM appliances can be configured not only as handheld power tools but also as stationary power tools. In this context, typical power tools include handheld or vertical drills, screw drills, impact drills, drill hammers, and demolition hammers. Planers, angle grinders, vibratory grinders, polishers, or the like. However, motor-driven gardening appliances, such as lawnmowers, lawn trimmers, twig saws, or the like, can also be considered as EDM appliances. Furthermore, the invention can be applied to axial flux machines in household appliances or kitchen appliances (e.g., washing machines, dryers, vacuum cleaners, blenders, etc.).

[0010] Here, the term "axial flux machine" can include not only axial flux motors but also axial flux generators used to convert mechanical energy into electrical energy. Similarly, an axial flux machine should also be understood as an axial flux motor that is at least partially used to regenerate mechanical energy into electrical energy, for example, during electrodynamic braking of an axial flux motor.

[0011] In an extended embodiment of the invention, it is proposed that the stator teeth and the first stator yoke are formed of a composite material. This is particularly advantageous in ensuring a high torque density of the axial flux engine. Furthermore, the use of the composite material enables the tangential and radial extensions of the pole shoes to be incorporated into the construction of the stator teeth. This has the advantage that single-tooth windings can be embedded into the corresponding stator teeth, which in turn leads to a reduction in the number of winding heads. An additional embodiment of the first stator yoke made of composite material ensures a defined transition of flux from the stator teeth to the stator yoke. Here, the stator teeth and the first stator yoke formed of composite material are permanently connected to each other, especially bonded, through a joining process. Thus, a high fill factor of the stator windings can be achieved by externally winding the coil carrier by applying the stator windings, or single-tooth windings, to the stator teeth during the joining process.

[0012] In another configuration of the axial flux engine according to the invention, a second stator yoke, composed of soft magnets, is arranged between the first stator yoke and the stator teeth in the axial direction of the machine shaft. This second stator yoke stabilizes the stator under strong mechanical stress and ensures improved flux guidance due to its high permeability.

[0013] To interrupt the eddy current path, the second stator yoke is constructed as a lamination assembly with multiple slots distributed along its outer periphery for receiving composite material. Here, the position of the slots is more important than their width. Additionally, the second stator yoke has annularly arranged, arc-shaped notches for receiving stator teeth. Each slot interrupts the outer periphery of the second stator yoke up to its respective radially recessed notch.

[0014] Each stator tooth has an arc-shaped tooth flange and an arc-shaped carrier frame. The tooth flange passes through an arc-shaped notch in the second stator yoke. The carrier frame surrounds the tooth flange and has a surrounding U-shaped profile for receiving the stator winding. The tooth flange and carrier frame are permanently connected to each other, particularly by bonding, through a joining process.

[0015] The rotor of an axial flux motor is constructed as a plate-shaped ring made of soft magnets. Furthermore, the rotor carries alternating polarized magnetic rings that work in conjunction with the stator windings to place the rotor in rotational motion during motor operation or to induce voltage in the stator windings during generator operation. Attached Figure Description

[0016] According to the following text Figures 1 to 10 The invention is illustrated by way of example, wherein the same reference numerals in the drawings denote the same components having the same function.

[0017] It shows

[0018] Figure 1 A cross-section of the axial flux motor according to the invention, which in the first embodiment takes the form of a single-sided axial flux motor.

[0019] Figure 2 : A schematic view of another embodiment of the stator of the axial flux engine according to the present invention.

[0020] Figure 3 : Figure 2 An exploded view of the stator in a schematic view without stator windings.

[0021] Figure 4 : A schematic partial view of the stator according to the invention in another embodiment,

[0022] Figure 5 : A schematic view of another embodiment of the rotor of the axial flux machine according to the present invention.

[0023] Figure 6 A schematic view of the housing of an axial flux generator according to the present invention.

[0024] Figure 7 : Figure 6A further schematic view of the empty housing of the axial flux engine according to the present invention.

[0025] Figure 8 A schematic cross-sectional view of another embodiment of the cooling air guiding device in an axial flux machine according to the present invention.

[0026] Figure 9: Two embodiments of the delta parallel circuit of the single-tooth winding of the stator winding of the axial flux engine according to the present invention, and

[0027] Figure 10 Electrical discharge machining tools, particularly power tools, that have an axial flux mechanism according to the invention, which are in the form of a drill hammer. Detailed Implementation

[0028] exist Figure 1 A cross-sectional view of a first embodiment of the axial flux transfer motor 10 according to the present invention is shown. The axial flux transfer motor 10 can also be configured as an axial flux motor or an axial flux generator. A disc-shaped rotor 14 is arranged torsionally on the machine shaft 12 of the axial flux transfer motor 10. The rotor 14 is constructed as a plate-shaped ring 16 made of soft magnets and carries alternately magnetized magnetic rings 18, which will also be referred to Figure 5 The magnetic ring will be discussed in more detail. However, since the rotor 14 is generally not exposed to alternating fields and the risk of eddy current losses is relatively small, the rotor 14 can also be made of a non-soft magnetic material (e.g., iron) or of a soft magnetic steel with a low carbon content. In the axial direction A of the motor shaft 12, a similarly disc-shaped stator 20 is adjacent to the rotor 14, or rather, to the magnetic ring 18. This stator is configured as a winding carrier 22 for at least one stator winding 24 (see...). Figure 2 The stator has a first stator yoke 26, which serves as a magnetic yoke for the magnetic field generated by the stator windings 24 and the magnetic ring 18. The rotor 14 can be put into rotational motion relative to the stator 20, or stator windings 24, by the motor shaft 12. For this purpose, the motor shaft 12 is connected on the one hand by a first bearing 28 integrated into the stator yoke 26, and on the other hand by a housing 32 received in the electrical discharge machining tool 34 (see...). Figure 10The second bearing 36 in the first stator yoke is supported in a rotatable manner, with the first bearing constructed, for example, as a fixed bearing 30, and the second bearing constructed, for example, as a floating bearing 38. The first and second bearings 28 and 36 are preferably constructed as ball bearings. The first bearing 28 is directly integrated into the winding carrier 22 and / or the first stator yoke 26. Therefore, the first bearing can be, for example, press-fitted or injected. Since the axial flux machine, especially the single-sided one, has a very high traction force in the axial direction A of the machine shaft 12 in the air gap between the rotor 14 and the stator 20, this traction force can be supported by the first bearing 28 in the first stator yoke 26, which is constructed as a fixed bearing 30. Therefore, it is not necessary to use the housing 32 of the electrical discharge machining tool 34 and / or the housing of the axial flux machine (see...). Figure 6 and Figure 7 It receives axial force.

[0029] To cool the axial flux motor 10, a fan impeller 40 is torsionally arranged on the machine shaft 12, which delivers cooling air through the axial flux motor 10. For this purpose, the fan impeller 40 preferably draws in cooling air radially so as to subsequently deliver the cooling air axially through the axial flux motor 10.

[0030] Figure 2 A schematic view of another embodiment of the disc-shaped stator 20 of the axial flux linkage 10 according to the invention is shown. The stator 20 essentially comprises a first stator yoke 26, a second stator yoke 42, and a winding carrier 22, the second stator yoke being arranged adjacent to the first stator yoke in the axial direction A of the machine shaft 12, and the winding carrier being arranged adjacent to the second stator yoke 42 in the axial direction A of the machine shaft 12. The winding carrier 22 is essentially composed of a plurality, particularly six, stator teeth 44, which carry stator windings 24, wherein each stator tooth 44 is associated with a single-tooth winding 46 of the stator winding 24. (Refer to...) Figure 9a The single-tooth windings 46 are electrically connected to each other in the delta parallel circuit 48.

[0031] The stator teeth 44 and the first stator yoke 26 of the stator 20 are formed of a composite material (soft magnetic composite, abbreviated as SMC) and are permanently connected to each other, especially bonded, through a bonding process. The SMC material consists of high-purity iron powder, each individual particle of which has a specialized surface coating. This electrically insulating surface ensures high resistance even after extrusion and heat treatment, which in turn minimizes or avoids eddy current losses. Particularly advantageous compared to prior art axial flux motors is the ability to provide an axial flux motor or axial flux motor that is extremely resistant to mechanical stress and simultaneously offers excellent performance and efficiency, or provides high torque. The engagement of the stator teeth 44 with the first stator yoke 26 is achieved by applying the stator winding 24, or a single-tooth winding 46, to the stator teeth 44 during the engagement process, thereby achieving external winding of the winding carrier 22. This allows for a high fill factor of the stator winding 24.

[0032] Unlike the first stator yoke 26, the second stator yoke 42 of the rotor 20 is composed of soft magnets and is constructed as a lamination group 48 (see...). Figure 3 The lamination assembly has multiple, particularly six, slots 50 distributed on the outer periphery of the lamination assembly and used to receive the composite material. The number of slots 50 corresponds here to the number of stator teeth 44. The second stator yoke 42 thus stabilizes the stator 20 under strong mechanical stress and ensures improved flux guidance due to its high permeability. The slots of the lamination assembly 48 not only promote better reception of the composite material and thus result in higher stability of the stator 20, but also ensure optimized guidance of eddy currents caused substantially by the stator windings 24.

[0033] according to Figure 3 The second stator yoke 42 for receiving stator teeth 44 has annularly arranged, arc-shaped notches 52, wherein each slot 50 interrupts the outer periphery of the second stator yoke 42 up to the radially recessed notch 52. Each stator tooth 44 is formed by an arc-shaped tooth flange 54 and an arc-shaped carrier frame 56, the tooth flange passing through the arc-shaped notch 52 of the second stator yoke 42, the carrier frame surrounding the tooth flange 54, the carrier frame having a surrounding U-shaped profile 58 for receiving stator windings 24, or single-tooth windings 46. The tooth flange 54 and the carrier frame 56 are permanently connected to each other, particularly by bonding, through a joining process.

[0034] Figure 4 A schematic view of a portion of the stator 20 according to the invention in another embodiment is shown. Here, the stator teeth 44, or rather its tooth flanges 54 (see...) Figure 3The stator tooth 44 is guided through the notch 52 of the second stator yoke 42 and permanently connected to the first stator yoke 26 by laser welding. In the first stator yoke 26, a drilled hole 60 is provided approximately centrally on each face of the stator tooth 44 lying flat on the first stator yoke 26, through which the stator tooth 44 can be connected to the first stator yoke 26 by means of laser welding. The weld extends along the entire periphery of the drilled hole 60 to permanently connect the first stator yoke 26 and the corresponding stator tooth 44. However, alternatively, the weld can also be provided to extend only point-by-point along the periphery of the drilled hole 60. Due to the welding at the center of each stator tooth 44, the guidance of magnetic flux is only slightly affected, and the high-plane parallelism of the stator tooth 44 to the radial air gap located between them can be achieved. By avoiding adhesion, the adhesive gap between the stator teeth 44 and the first stator yoke 26 can be effectively avoided, and it is not necessary to fix the stator teeth 44 and the first stator yoke 26 during the hardening of the adhesive portion. (Refer to...) Figure 1 Alternatively, one could consider omitting the second stator yoke 42 and instead directly connecting the first stator yoke 26 to the stator teeth 44 made of composite material, particularly by means of the boreholes 60 in the first stator yoke 42, which is constructed as a plate-shaped ring 16 made of soft magnets.

[0035] exist Figure 5 The diagram shows a cross-sectional schematic of the rotor 14 of the axial flux transfer motor 10 according to the present invention. The rotor 14 is constructed as a plate-shaped ring 16 made of soft magnets. Furthermore, the rotor carries an alternating polarized magnetic ring 18, which works in conjunction with the stator windings 24 of the stator 20 to place the rotor 14 in rotational motion during motor operation or to induce voltage in the stator windings 24 during generator operation. The magnetic ring 18, not shown in detail, has an arcuate magnet configuration such that the surface of the magnet coincides to a maximum extent with the arcuate stator teeth 44 to achieve optimized flux and high torque. Instead of the alternating polarized magnetic ring 18, a ring with embedded single magnets can also be considered. As mentioned above, the rotor 14 is generally not exposed to an alternating field, therefore, no or very little eddy current loss is generated. Therefore, the rotor 14 of the axial flux transfer motor 10 can also be constructed of a non-soft magnetic material.

[0036] In a preferred embodiment of the invention, the plate-like ring 16 of the rotor 14 is constructed as a rotor yoke 62, which is either permanently connected to the bidirectional fan 40, particularly by bonding, through a joining process, or serves itself as a bidirectional fan 64. Here, the bidirectional fans 40, 64 have at least one radial airflow direction 66 and an axial airflow direction 68 for cooling the axial flux motor 10, particularly for cooling the stator 20, or stator winding 24, and the rotor 14. The radial airflow direction 66 is achieved substantially by a plurality of radial air blades 70 arranged circularly in the outer radius region of the bidirectional fans 40, 64, while the axial airflow direction 68 is achieved by a plurality of axial openings 72 arranged in the inner radius region of the rotor yoke 62.

[0037] Therefore, refer to Figure 6 The bidirectional fans 40 and 64 cause radial intake 74 of airflow 76, accompanied by axial flow 78 through the stator 20 and rotor 14 of the axial flux transfer motor 10 and radial exhaust 80 of the heated airflow 76 from the housing 82 of the axial flux transfer motor 10. The radial intake 74 of airflow 76 is achieved through the stator teeth 44 (see...) Figure 2 The process is carried out in the air gap between the rotor and rotor 14, and in the region of the first stator yoke 26 of the stator 20, especially on the end side 84 of the first stator yoke 26 at the far end as seen from the rotor 14.

[0038] exist Figure 7 The diagram shows an axial flux mechanism 10 with a housing 82 containing an axial flux motor and a cover 86 that closes the housing. Figure 8 The housing 82 is shown without the axial flux mechanism 10 and the cover 86. The housing 82 is open on one side to receive the cover 86 and has substantially closed end sides 88 on the opposite side (see [reference]). Figure 8 The cover 86 encloses the housing 82, and thus forcefully locks the stator 20 and rotor 14 of the axial flux transfer motor 10 together. "Substantially closed" in this context should be understood as the end side 88 being able to have multiple openings 90, such as for cooling, serving as cable passages, and / or as through-holes for the machine shaft 12; however, it should also be understood alternatively that the end side 88 is completely closed. The housing 82 is constructed in a cylindrical shape and secures the stator 20 such that a defined air gap is created between the rotor 14, or the magnetic ring 18 of the rotor, and the stator 20, or the winding carrier 22 of the stator. To reduce or avoid eddy current losses, the housing 82 is made of a magnetically insulating material with the lowest possible permeability, such as plastic (PA66). The cover 86 can also be constructed accordingly.

[0039] A first bearing 28, configured as a fixed bearing 30, is fixed in the bearing flange 92 of the cover 86. This first bearing supports the machine shaft 12 in a non-displaceable manner, while the substantially closed end side 86 of the housing 82 has a second bearing 36, configured as a floating bearing 38, in another bearing flange 94, for supporting the machine shaft 12 in a displaceable manner. In this way, the housing 82 can be easily pushed open after the axial flux machine 10 is assembled and then removed for possible maintenance work.

[0040] On the open side of the housing, a plurality of notches 96 and tabs 98 are alternately arranged around the periphery of the housing 82 for receiving and fixing the stator 20. Here, radial protrusions are distributed around the periphery of the first and second stator yokes 26, 42 of the stator 20 (see...). Figure 2 and Figure 3 The cover 86 is fitted into a corresponding recess 96 in the housing 82. Correspondingly, the cover 86 also includes a radially protruding portion configured as a tab 106, which fits into the recess 96 in the housing 82. In this way, a high axial force of the axial flux motor 10 can be discharged in the direction of the cover 86. At least one drilled hole 100 is provided in each tab 98 of the housing 82 for securing the cover 86 by means of a corresponding fastening device 102, in particular a screw 104, and thus also securing the stator 20. The fastening device 102 transmits the axial force of the axial flux motor 10 to the housing 82 and thus withstands shear force.

[0041] The opening 90 on the substantially closed end side 88 of the housing 82 is configured as a ventilation opening 104 acting radially and / or axially, particularly as a ventilation outlet 106, for cooling the axial flux engine 10 (see also...). Figure 6 Furthermore, the housing 82 has a plurality of radially distributed ventilation openings 108, particularly ventilation inlets 110, located approximately at the center between the substantially closed end side 88 and the open side opposite in the axial direction A. In addition to the opening 90 for cooling the axial flux engine 10, further openings 90 are provided, particularly in the tabs 98 of the housing 82, which can be used as guide portions 112 for sensor lines or the like.

[0042] exist Figure 9a In the circuit diagram, the stator winding 22 is represented by the six single-tooth windings 46 of the stator tooth 44 (see...). Figure 2The delta-parallel circuit 48 is shown. For each phase, two single-tooth windings 46 are connected in parallel at connection points U and V, V and W, or W and U, respectively. The delta circuit itself causes the entire supply voltage to drop across each single-tooth winding 46. This results in an increase in the number of turns of the single-tooth winding 46 to achieve a specific required speed when the motor is running, or a specific required energy output when the generator is running. With the additional parallel circuit, the winding wire diameter can be increased in a particularly advantageous manner, and thus the resulting internal resistance can be reduced. Therefore, compared to the common star circuit, the delta-parallel circuit 48 enables a reduction in the internal resistance of the axial flux motor 10, which leads to a significant increase in the power capability of the axial flux motor 10 compared to solutions to date. Figure 9b An alternative implementation of a delta-parallel circuit 48 for a total of nine single-tooth windings 46 for stator winding 22 is shown.

[0043] exist Figure 10 The text shows that it has the following characteristics: Figure 1 This is one embodiment of the electrical discharge machining (EDM) tool 34 of the axial flux unit 10 according to the present invention. The EDM tool 34 is configured as a power tool 112, which takes the form of a grid-operated drill hammer having an electric motor-driven impactor 114 that places a drill chuck 116 (not shown) for use with an insert tool in a rotary and / or impact motion. The specific configuration of the drill hammer is not discussed in detail here, as it is well known to those skilled in the art. The EDM tool can also be understood as any other battery-operated or grid-operated power tool 112 used for machining workpieces using an electrically driven insert tool. Here, the EDM tool can be configured not only as a handheld power tool but also as a stationary power tool. In this context, typical power tools include handheld or vertical drills, screw drills, impact drills, drill hammers, and demolition hammers. Planers, angle grinders, vibratory grinders, polishers, or the like. However, motor-driven gardening appliances, such as lawnmowers, lawn trimmers, twig saws, or the like, can also be considered as EDM appliances. Furthermore, the invention can be applied to axial flux machines in household appliances or kitchen appliances (e.g., washing machines, dryers, vacuum cleaners, blenders, etc.).

[0044] The axial flux motor 10 of the power tool 112, which operates as an axial flux motor, drives the impact machine 114 via a transmission 118 in a known manner through the machine shaft 12 of the axial flux motor. Here, the axial flux motor 10 is operated by a main switch 122 arranged in the D-shaped handle 120 of the power tool 112. This main switch, in conjunction with electronic devices (not shown), energizes the stator winding 22 connected in the delta-parallel circuit 48. The stator 20 of the axial flux motor 10 is directly received in the housing 32 of the power tool 112. For this purpose, the stator 20 and the housing 32 are permanently connected to each other through a joining process, particularly by bonding. However, alternatively, the stator 20 can also be permanently connected to the housing 32 by form-fitting, particularly by verpressing. Furthermore, it is possible to provide a second bearing 36, particularly a floating bearing 38, connected to the machine shaft 12 of the axial flux motor 10, in addition to the housing 32 of the power tool 112 or the transmission housing 122. Figure 1 The axial flux transfer motor 10 shown, the power tool 112, or the electrical discharge machining tool 34 can also (without limitation) be equipped with according to Figures 6 to 8 Axial flux generator 10.

[0045] Finally, it should be noted that the present invention is not limited to the present invention based on Figures 1 to 10 The illustrated embodiments are not limited to the number of stator teeth, single-tooth windings, and magnetic ring magnets mentioned.

Claims

1. An axial flux transfer motor (10) for an electrical discharge machining (34) having a machine shaft (12), a disc-shaped stator (20), and a disc-shaped rotor (14) arranged adjacent to the stator (20) in an axial direction (A) of the machine shaft (12), wherein, The stator (20) is configured as a winding carrier (22) for at least one stator winding (24), and a rotor (14) torsionally connected to the machine shaft (12) is capable of rotational motion relative to the stator (20), wherein the stator (20) is composed of a combination of composite material and soft magnets, and a plurality of stator teeth (44) and a first stator yoke (26) of the stator (20) are formed of the composite material, characterized in that a second stator yoke (42) composed of soft magnets is arranged between the first stator yoke (26) and the stator teeth (44) in the axial direction (A) of the machine shaft (12).

2. The axial flux engine (10) according to claim 1, characterized in that, The axial flux motor (10) is a single-sided axial flux motor.

3. The axial flux engine (10) according to claim 1, characterized in that, The machine shaft is a motor shaft.

4. The axial flux engine (10) according to claim 1, characterized in that, The composite material is a fiber-plastic composite.

5. The axial flux engine (10) according to any one of claims 1 to 4, characterized in that, The stator teeth (44) formed from the composite material and the first stator yoke (26) are permanently connected to each other through a bonding process.

6. The axial flux engine (10) according to claim 5, characterized in that, The stator teeth (44) formed from the composite material and the first stator yoke (26) are permanently bonded together through a bonding process.

7. The axial flux engine (10) according to any one of claims 1 to 4, characterized in that, The second stator yoke (42) is constructed as a lamination group (48) having a plurality of grooves (50) distributed on the outer periphery of the lamination group for receiving the composite material.

8. The axial flux engine (10) according to any one of claims 1 to 4, characterized in that, The second stator yoke (42) has an annularly arranged, arc-shaped notch (52) for receiving the stator teeth (44).

9. The axial flux engine (10) according to claim 8, characterized in that, Each slot (50) interrupts the outer periphery of the second stator yoke (42) up to the radially built-in notch (52).

10. The axial flux engine (10) according to claim 8, characterized in that, Each stator tooth (44) has an arc-shaped tooth flange (54) and an arc-shaped carrier frame (56), the tooth flange passing through an arc-shaped notch (52) of the second stator yoke (42), the carrier frame surrounding the tooth flange (54), the carrier frame having a surrounding U-shaped profile (58) for receiving the stator winding (22).

11. The axial flux engine (10) according to any one of claims 1 to 4, characterized in that, The rotor (14) is constructed as a plate-shaped ring (16) made of soft magnets.

12. An electrical discharge machining (EDM) appliance (34) having an axial flux motor (10) according to any one of claims 1 to 11.

13. The electrical discharge machining tool (34) according to claim 12, characterized in that, The electrical discharge machining tool is an electric machine tool (112).

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