Closure means for a stator slot

Abstract

The invention relates to a closure means (100) for closing a stator slot (510) in a stator (500) of an electric motor. The closure means (100) has a main body (101), said main body having a cross-section that is continuous along a longitudinal direction (LR) and having a ferromagnetic material. The cross-section has two spring sections (110, 120) each with oppositely oriented contact surfaces (111, 121) for making planar contact with a corresponding mating contact surface (511, 512) of the stator slot (510). The spring sections (110, 120) are elastically deformable between a relaxed position (P0) and a closed position (P2) when closing the stator slot (510) in order to generate spring forces onto the respective mating contact surface (51, 512) in a width direction (BR) transverse to the longitudinal direction (LR) via the two contact surfaces (111, 121). Furthermore, the cross-section has a connection free space (140) between the two spring sections (110, 120), which connection free space is free of ferromagnetic material. The invention further relates to a stator (500) which has at least one of the closure means (100). The invention additionally relates to mounting methods for mounting the closure means (100) in a stator slot (510).

Description

[0001] Sealing device for a stator slot

[0002] The invention relates to a closing means for closing a stator slot and a stator with the closing means. The invention also relates to methods for closing a stator slot with the closing means.

[0003] Electric motors are used to power hybrid and electric vehicles. In these vehicles, an electric motor converts the electrical power from a battery into mechanical power. Specifically, this conversion is achieved by generating opposing magnetic fields in a stator and a rotor, which in turn creates mechanical forces that cause the rotor to rotate. A rotating magnetic field in the stator can be generated by a multiphase electric current flowing through stator windings arranged in stator slots.

[0004] Stator configurations are known from the prior art in which the stator slots are open on both sides or at least on the rotor-side circumferential surface. This allows the use of continuous stator windings, which can simply be inserted into the stator slots. This increases the efficiency of the winding process. Often, the slot openings on the rotor-side circumferential surface are closed with wedge-shaped slots after the winding process is complete.

[0005] The slot wedges can, for example, be made of ferromagnetic material. A common material is a slot wedge made of a pressed fiberglass composite consisting of iron powder, glass fibers, and epoxy resin. Such slot wedges thus exhibit magnetic properties, which can advantageously reduce the effective air gap length of the electric motor. However, a disadvantage is that the slot wedges generate stray inductances in the stator, as the magnetic slot wedges create new paths for magnetic field lines. For example, a slot wedge can guide magnetic field lines from one stator tooth back to an adjacent stator tooth, thereby increasing stray fluxes. This reduces the efficiency and performance of the electric motor, as stray fluxes do not contribute to torque generation. Another disadvantage is that the slot wedges are relatively brittle due to their iron powder content.Therefore, even minor manufacturing inaccuracies in the stator slots can lead to problems during the installation of the keyways. Thermal fluctuations or mechanical loads during operation or installation can also cause the keyways to be damaged or to come loose from the stator slot.

[0006] The slot wedges from the prior art - as known, for example, from documents US 2745030 or US 8330318 B2 - thus have disadvantages with regard to their assembly, mechanical load-bearing capacity and magnetic behavior, which reduce the service life, performance and efficiency of the electric motors.

[0007] It is an object of the present invention to at least partially overcome the disadvantages described above. In particular, it is an object of the present invention to provide a closing device for stator slots that is improved with regard to assembly, mechanical load-bearing capacity and magnetic flux performance.

[0008] The foregoing problems are solved by a closure means having the features of claim 1, by assembly methods having the features of claims 14 or 15, and by a stator having the features of claim 16.

[0009] Further advantages and features of the invention will become apparent from the dependent claims, the description, and the drawings. Features and details described in connection with the closure device according to the invention naturally also apply in connection with the stator and the assembly methods according to the invention, and vice versa, so that the disclosure of the individual aspects of the invention always refers, or can refer, to each other.

[0010] One aspect of the present invention relates to a closing means for closing a stator slot of an electric motor stator in a closing direction. The closing means comprises a base body having a cross-section that extends continuously along a longitudinal direction. The base body further comprises a ferromagnetic material. The cross-section includes a first spring section. The first spring section has a first contact surface for making planar contact with a first mating surface of the stator slot. The cross-section further comprises a second spring section. The second spring section has a second contact surface for making planar contact with a second mating surface of the stator slot. The second contact surface is oriented opposite to the first contact surface.The first spring section and the second spring section each have at least one spring clearance between two spring legs to allow the spring sections to deform elastically from a relaxed position to a closed position when the stator slot is closed, in order to generate spring forces across the two contact surfaces in a lateral direction transverse to the longitudinal direction on the opposing contact surfaces. The cross-section also includes a connection clearance between the two spring sections, which is free of ferromagnetic material.

[0011] Thus, a closure means is disclosed for closing a stator slot of a stator of an electric motor in a closure direction.

[0012] The term "closing means" can be understood to mean, in particular, a device or structure that restricts access to a spatial region. For example, the closing means can be a keyway. The "stator slot" can be understood, in particular, as an elongated opening between two stator teeth of a stator. "Closing" can be understood, in particular, as covering or restricting access. The "closing direction" can be understood, in particular, as a direction along which passage between two spatial regions is blocked. If, for example, the closing means provides a separating surface, the closing direction can be parallel to its surface normal.

[0013] The closure element has a base body that extends continuously along a longitudinal direction with a cross-section. The base body is made of a ferromagnetic material.

[0014] The "base body" can be understood in particular as a three-dimensional profile body whose cross-section is constant along its length. The base body can be one or more parts. The "ferromagnetic material" can be understood in particular as a soft magnetic material and / or as a material that has a magnetic permeability p that is significantly greater than one. For example, the magnetic permeability p can be greater than 10 and less than 10 6 Colloquially, such materials are often called "magnetically conductive." The ferromagnetic material preferably contains iron, cobalt, or nickel. For example, the closure element can be made of weldable sheet steel or contain silicon steel.

[0015] The cross-section has two spring sections with contact surfaces for flat contact with opposing contact surfaces of the stator slot.

[0016] A "spring section" can be understood, in particular, as a volume section of the base body with which a spring force can be generated by a reversible relative movement of two subsections against each other. Preferably, the spring section has a deflection range within which the subsections can be deflected relative to each other by means of elastic extension, thus making the relative movement completely reversible. For example, the spring section can be designed as a detent or snap connection. "Planar contact" can be understood, in particular, as the contact of two surfaces against each other. The opposing contact surfaces can, for example, each be arranged on a tooth flank of the stator. The stator slot extends between these two tooth flanks.

[0017] The two spring sections each have at least one spring clearance between two spring legs in order to elastically deform the spring sections from a relaxed position to a closed position.

[0018] A "spring clearance" can be understood as a continuous, elongated volume within the base body, which is at least partially enclosed by the spring legs. A "relaxed position" can be understood, in particular, as a position in which the base body is at rest without any external influence. A "locked position" can be understood, in particular, as a position in which spring forces occur in the base body, corresponding to the contact of the mating surfaces with the mating surfaces. The locked position can occur, for example, in the installed state. Thus, depending on the configuration of the stator slot and the arrangement of the locking element within the stator slot, there can be one or more locked positions. The cross-section has a connection clearance between the two spring sections, which is free of ferromagnetic material.

[0019] A "connection gap" can be understood as a continuous, elongated volume region within the base body, which is at least partially surrounded by structural components of the base body. The connection gap is free of ferromagnetic material, i.e., it contains no ferromagnetic material. Preferably, the connection gap can be made of a material with a magnetic permeability p of approximately 1, and more preferably, a magnetic permeability p of 0 to 10. Colloquially, these materials are often referred to as "magnetically non-conductive." For example, plastic or air can be used in the connection gap.

[0020] The invention thus provides a locking device that has a region free of ferromagnetic material between the spring sections used to secure the locking device in the stator slot. This interrupts the magnetic conductivity between the spring sections, resulting in a correspondingly low connection gap. Consequently, stray fluxes that would otherwise extend from the stator teeth through the locking device when installed are reduced. Since the locking device contains ferromagnetic material elsewhere, the effective air gap length can be further reduced. This results in an anisotropy of the magnetic permeability, as the locking device exhibits reduced permeability in the lateral direction due to the connection gap. The spring sections also facilitate the securing of the locking device in the stator slot.Temperature fluctuations and manufacturing inaccuracies can be compensated for, for example, by the expansion of the spring legs. The spring sections also allow for easy assembly and disassembly.

[0021] According to a preferred embodiment, the spring sections can each be arranged at opposite ends of the cross-section in the lateral direction in order to generate opposing spring forces in the lateral direction on the opposing contact surfaces in the closed position. Preferably, the locking element can extend between the contact surfaces in the lateral direction. Furthermore, preferably, at least the spring sections can comprise the ferromagnetic material.

[0022] By providing high conductivity for magnetic field lines, the ferromagnetic spring sections can align and amplify the magnetic flux in the radial direction of the stator, thus increasing the useful flux. In this way, the useful flux is improved and stray fluxes are suppressed.

[0023] For a secure and reliable fastening of the locking means in the stator slot, according to a preferred embodiment the cross-section of the locking means can have an extent in the lateral direction that is larger in the relaxed position than in the closed position.

[0024] To reliably prevent a short circuit between the stator teeth, the spring sections may preferably have an insulating coating, at least on the contact surfaces, for electrical insulation of the locking element from the stator. For example, the insulating coating may be a dielectric material such as polyethylene, polytetrafluoroethylene, or ceramic. The insulating coating may be provided as a film or a coating.

[0025] According to a further preferred embodiment, at least the spring leg can be arranged with the contact surface inclined relative to the closing direction.

[0026] Preferably, the spring legs of the spring sections can be arranged to run almost parallel to each other.

[0027] This allows for preferential steering of the magnetic flux in the radial direction of the stator in the closed position.

[0028] According to a preferred embodiment, the cross-section can further comprise a bridge section. The bridge section can connect the two spring sections and at least partially surround the connection gap. Preferably, the bridge section can extend between the two spring sections along the width direction with an arc segment having an arc curvature. The arc segment can preferably be U- or V-shaped. Preferably, the arc segment can extend with a curvature in or against the closing direction. The arc segment can, for example, also comprise the ferromagnetic material.

[0029] The bridge section thus forms a material bridge between the two spring sections in the locking mechanism, creating a magnetic detour around the gap between the two sections. In particular, the bridge section can be a kind of "magnetic labyrinth" made of coiled sections of ferromagnetic material. This helps to counteract the formation of stray fluxes.

[0030] According to a further preferred embodiment, the connection gap can be free of material. For example, the connection gap can contain air and / or be designed as an air gap.

[0031] This can increase the spring action of the locking device, as additional space is available for elastic deformation of the spring sections.

[0032] According to a further preferred embodiment, the locking device can also include at least one stabilizing element made of a non-ferromagnetic material. Preferably, the stabilizing element can be arranged between the two spring sections. Alternatively or additionally, the stabilizing element can preferably be arranged in the connection gap. The stabilizing element can, for example, have a T-profile shape. The stabilizing element can, for example, be made of a plastic material, an aluminum alloy, or a fiber-reinforced composite material.

[0033] By selecting the appropriate material for the stabilizing element, the magnetic conductivity within the connection gap can be further adjusted. Additionally, the stiffness of the closure element can be increased.

[0034] To further reduce scattering losses, the stabilizing body can preferably be integrally connected to the spring sections. For example, the spring sections can each be connected to the stabilizing body by means of an adhesive bond. Alternatively, it is also conceivable to provide the stabilizing body by overmolding the spring sections with a plastic material on the closure element. According to a preferred embodiment, the base body can be formed in one piece. For example, the base body can be a bent part. Thus, the base body can be bent from a magnetic steel sheet or silicon steel sheet. A CNC bending machine can be used for this purpose. Preferably, the base body, or at least the spring sections, can have a uniform material thickness along their length, i.e., in their extension along the width direction.Preferably, the material thickness can be between 0.2 mm and 1.0 mm, or between 0.3 mm and 0.7 mm. Preferably, the bridge section can be integrally connected to the two spring sections.

[0035] In this way, the sealing element can be made from a material with high mechanical strength, high electrical resistance, and high magnetic saturation, further enhancing its advantages. At the same time, the aforementioned material thicknesses are particularly suitable for use in small to medium-sized electric motors. Additionally, the production effort for the sealing element can be significantly reduced compared to the effort required to manufacture the keyway from a fiberglass composite.

[0036] According to a further preferred embodiment, the base body can be made up of multiple parts. Preferably, the base body can have at least one ferromagnetic sub-base body with the spring sections.

[0037] According to a preferred embodiment, the multi-part base body can comprise two separate sub-base bodies. Preferably, each sub-base body can have at least one of the two spring sections and surround at least a portion of the connection gap. Furthermore, the sub-base bodies can preferably be made of the same material. Preferably, the sub-base bodies can be separated from each other in cross-section by a gap and each arranged in contact with the stabilizing body to support the spring forces against each other on the stabilizing body. Preferably, the sub-base bodies can be designed to be complementary to each other in order to form the cross-section when assembled. Furthermore, preferably, the sub-base bodies can be designed such that, when assembled, they complete the arch segment of the bridge section.

[0038] In this way, the locking device can be provided in a multi-part design, which simplifies assembly.

[0039] According to a preferred embodiment, the spring sections can be identical to each other. Preferably, the spring sections can be arranged as mirror images of each other in the width direction with respect to the connection clearance.

[0040] This allows for a symmetrical distribution of the spring forces. This enables the locking mechanism to be positioned in a stabilizing manner within the stator slot itself. At the same time, destabilizing torques on the locking mechanism can be avoided.

[0041] It is further advantageous if the cross-section is symmetrical according to a preferred embodiment. Preferably, an axis of symmetry, transverse to the longitudinal and lateral directions, can extend through the connection space.

[0042] According to a further preferred embodiment, the contact surfaces can each be arranged inclined with respect to the locking direction in the direction of the connection clearance in order to define a wedge angle. Alternatively or additionally, the cross-section can widen along the locking direction in its width.

[0043] This allows the locking device to be wedged in the stator slot, thus achieving a secure fastening. For example, the locking device can also provide snap-lock connections in this way.

[0044] According to a preferred embodiment, at least one of the spring sections can have at least one folded segment with a folded curvature. Preferably, the at least one folded segment can extend away from one of the spring legs. More preferably, the spring section can have at least one folded segment that extends into the spring clearance. In particular, the folded segment can extend into the spring clearance in multiple folds. This allows for the provision of additional spring-like elements in the locking device, which enable further deformation and higher spring forces in the lateral direction and / or the locking direction during assembly. Furthermore, additional labyrinth paths can be provided in the locking device, by means of which targeted guidance of the magnetic flux is possible.

[0045] According to a further preferred embodiment, at least one of the spring sections can have a locking segment to limit deformation of the spring leg in the closed position as it returns to the relaxed position. Preferably, the locking segment can extend in the lateral direction opposite to or in the direction of the contact surface.

[0046] This prevents the locking element from detaching and moving out of the stator slot during operation. Specifically, the locking element can only be removed from the stator slot by applying disassembly force to bring it into an installation position. Additionally, the magnetic flux in the air gap is distributed more evenly by the locking element.

[0047] To facilitate the assembly and proper placement of the locking device in the stator slot, according to a preferred embodiment at least one of the spring sections can have a guide segment on the contact surface to guide the spring section into the locking position contacting the corresponding counter-contact surface during assembly.

[0048] According to a further preferred embodiment, the base body can also have a contact surface oriented in the closing direction in order to transfer force components of the generated spring forces in the closing direction via the contact surface to a counter-contact surface for a radial fixing of windings in the stator slot.

[0049] In this way, the windings can be secured in the stator slot using the locking device.

[0050] Another aspect of the invention relates to a method for closing a stator slot of an electric motor stator in a closing direction. The closing means described above is preferably provided as a single piece. The closing means is moved from its relaxed position to an assembly position by applying assembly forces, whereby at least one of the two spring sections is elastically deformed in the lateral direction. The closing means, thus deformed, is inserted into the stator slot in the assembly position along the closing direction or the longitudinal direction. The closing means is moved from the assembly position to the closed position by removing the assembly forces and elastically deforming both spring sections until the contact surfaces of the contact surfaces with the mating contact surfaces of the stator slot are achieved.

[0051] The “assembly position” can be understood in particular as a position of the locking device in which the spring sections are exposed to external assembly forces and exhibit a higher elastic deformation than in the locking position.

[0052] In this way, an assembly method can be provided that allows the locking device to be inserted not only in the longitudinal direction of the stator but also in its radial direction. This prevents damage to coatings on the stator and the locking device. Therefore, in addition to the advantages already described for the locking device, benefits can also be achieved regarding the quality and durability of the stator.

[0053] A further aspect of the invention relates to another method for closing a stator slot of an electric motor stator in a closing direction. In this method, the closing element is provided in multiple parts. The two component bases are inserted into the stator slot along the longitudinal direction, so that the component bases are aligned in the stator slot in the lateral direction and are partially enclosing the connection gap between the opposing mating surfaces. The stabilizing element is inserted longitudinally into the connection gap enclosed by the component bases. The closing element is brought into the closing position by bringing the stabilizing element at least partially into contact with the component bases in the connection gap, thereby elastically deforming the component bases and generating spring forces on the mating surfaces of the stator slot.

[0054] This allows the assembly of the locking device to be divided into several steps and simplified. The sub-bases can be pre-assembled and then easily clamped to the stabilizing body. This protects the sub-bases from damage when inserted into the stator slot. Additionally, the assembly process can be simplified and automation facilitated.

[0055] Another aspect of the invention relates to a stator for an electric motor with a rotor. The stator has a stator body extending along a longitudinal axis. The stator body has stator slots for receiving windings, evenly distributed over a circumferential surface. The stator slots extend along the longitudinal axis and in a slot direction within the stator body. The stator further has at least one stator slot with the aforementioned closing means to close the stator slots, at least on the circumferential surface, in the closing direction.

[0056] The stator offers the same advantages and effects previously described for the locking device. In particular, the inventive design of the stator eliminates the need to weld the wire ends of the windings during final assembly, as pre-fabricated hairpin windings can be used, which already have a continuous electrical connection and therefore only need to be sealed with the locking device after insertion.

[0057] According to a preferred embodiment, the stator can be designed as an inner stator, wherein the circumferential surface can define an outer circumferential surface of the stator body, which can be enclosed by a rotor. Alternatively, the stator can be designed as an outer stator, wherein the circumferential surface can define an inner circumferential surface of the stator body for receiving a rotor.

[0058] Therefore, the stator can be used for various types of machines.

[0059] According to a further preferred embodiment, the stator can have slotted inserts for lining the stator slots, which are arranged in the stator slots between the stator body and the windings to electrically insulate the windings from the stator body. Preferably, the slotted insert can cover the winding on its circumferential surface. Furthermore, preferably, the sealing element can be arranged in the stator slot on top of the slotted insert, so that the slotted insert is positioned between the winding and the sealing element. The slotted insert can, for example, be made of paper.

[0060] This allows for additional electrical insulation between the stator body, the windings, and the locking mechanism.

[0061] According to a preferred embodiment, the stator slots can extend between two tooth flanks of adjacent stator teeth. Preferably, at least one stator tooth can have a tooth opening that extends along the longitudinal axis through the stator tooth. Preferably, the tooth openings are arranged in a stator tooth at a radial distance from the longitudinal axis that is identical to the radial distance of the connection clearance from the longitudinal axis.

[0062] In this way, the magnetic field can form uniformly in the air gap.

[0063] In a preferred embodiment, for additional fastening of the windings in the stator slots, the stator slots filled with the windings can be filled with a binding material, such as a resin.

[0064] It can also be advantageous if the stator slots are open at least on the circumferential surface. Alternatively, the stator slots can also be open on both sides in the radial direction. Furthermore, the windings preferably have at least two electrical phase strands.

[0065] Further advantages, features, and details of the invention will become apparent from the following description, in which exemplary embodiments of the invention are described in detail with reference to the figures. The figures schematically show:

[0066] Fig. 1 shows a top view of an embodiment of a closure device according to the invention in a relaxed position,

[0067] Fig. 2 shows an embodiment of a stator according to the invention with the

[0068] The locking device from Figure 1 in a locked position, Figure 3 the embodiment of Figure 2 in a perspective view,

[0069] Fig. 4 shows a detailed view of a section of Figure 3,

[0070] Fig. 5 shows a sectional view of a further embodiment of a stator according to the invention with the locking means from Figure 1 in a closed position,

[0071] Fig. 6 shows a detailed view of a section of Figure 5,

[0072] Fig. 7 shows a further embodiment of an invention

[0073] a locking means which is arranged in a locking position in a further stator according to the invention,

[0074] Fig. 8 shows the locking device from Figure 7 in a perspective view,

[0075] Fig. 9 shows a further embodiment of a closure means according to the invention, which is arranged in the closure position in a further stator according to the invention.

[0076] Fig. 10 Steps of an embodiment of an assembly method according to the invention for the locking device from Figure 9,

[0077] Figures 11 and 12 show further views of possible steps in the assembly process from Figure 10.

[0078] Fig. 13 shows an overview of the course of the magnetic fields for the different embodiments of the locking devices in a first electrical operating mode,

[0079] Fig. 14 shows an overview of the course of the magnetic fields for the different embodiments of the locking devices in a second electrical operating mode.

[0080] The figures show different views and aspects of the invention. One aspect of the invention relates to a closing means 100 for closing a stator slot 510 in a closing direction VR. For example, the closing means 100 can be a wedge-shaped groove that separates the interior of a stator slot 510 of a stator 500 from its surroundings. Figures 1 to 6 show an embodiment of such a closing means 100.

[0081] The closure element 100 shown in these figures has a one-piece base body 101 made of a ferromagnetic material. In the example shown in Figures 1 to 6, the base body 101 is preferably made of a silicon steel sheet, which was processed into the base body 101 in a bending machine. The base body 101 has a cross-section that is continuous along a longitudinal direction LR, as can be clearly seen in Figures 3 and 4. In Figures 1 to 6, the cross-section is shown in an exemplary symmetrical configuration. The continuous extent of the cross-section allows the base body 101 to provide a continuous cover surface for the stator slot 510.

[0082] The cross-section comprises a first spring section 110 with a first contact surface 111 and a second spring section 120 with a second contact surface 121, the second contact surface 121 being oriented opposite to the first contact surface 111. Preferably, the cross-section extends in the lateral direction BR between these two contact surfaces 111, 121. The contact surfaces 111, 121 can each be arranged inclined towards each other with respect to the locking direction VR in order to define a wedge angle. In this way, the extension of the cross-section in the lateral direction BR can increase along the locking direction VR.

[0083] The spring sections 110, 120 are each formed by a pair of spring arms 112, 113, 122, 123, between which a spring clearance 115, 125 extends. The spring sections 110, 120 can be deflected relative to each other by elastic deformation and define different positions for the locking element 100.

[0084] Figure 1 shows, for example, the locking device 100 in a relaxed position PO, in which the spring sections 110, 120 are not deformed. Preferably, the spring legs 112, 113, 122, 123 can each be connected in pairs via a bending leg with a small bending radius. The spring legs 112, 113, 122, 123 connected in this way can extend side by side along similar directions in the relaxed position PO. Figures 2 to 6 show the locking device 100 in a closed position P2, in which it is arranged in the stator slot 510 to close it. Figures 2 to 6 show that the spring sections 110, 120 in the closed position P2 make full contact with their contact surfaces 111, 121 on corresponding counter-contact surfaces 511, 512 of the stator slot 510.According to the elastic deformation of the spring legs 112, 113, 122, 123 relative to their position in the unloaded position PO, spring forces are generated in a lateral direction BR transverse to the longitudinal direction LR. This can, for example, enable a compression in the stator slot 510.

[0085] The two spring sections 110, 120 can preferably be identically designed, as shown by way of example, and arranged at opposite ends of the cross-section in the width direction BR, so that uniform clamping of the locking means 100 in the locking position P2 can be achieved via the two contact surfaces 111, 121 between the two counter-contact surfaces 511, 512.

[0086] By means of the spring sections 110, 120 and the cross-sectional design, a secure fastening of the fastening element 100 in a stator slot 510 can thus be achieved. However, the spring sections 110, 120 and the cross-sectional design can also influence the distribution of magnetic fields generated in the stator 500.

[0087] Thus, the respective two spring arms 112, 113, 122, 123 can, for example, extend almost parallel to each other in the closed position P2 in order to define preferred paths for the course of magnetic field lines. In this way, the spring sections 110, 120 can be used to steer magnetic field lines in the radial direction RR of the stator 500.

[0088] The cross-section further features a connection gap 140 between the two spring sections 110 and 120, which is free of ferromagnetic material. In Figures 1 to 6, the connection gap 140 is shown filled with air as an example. Of course, it is also conceivable to provide a different, non-magnetic material in the connection gap 140. The connection gap 140 is enclosed in Figures 1 to 6 by a bridge section.

[0089] The bridge section 130 surrounds the two spring sections 110, 120, which connects them via a substantially U-shaped arc segment 131 extending with a curve along the closure direction VR. Preferably, the angle of curvature of the arc segment 131 from Figures 1 to 6 can be more than 180 degrees but less than 300 degrees, for example, 270 degrees. A folding segment 117, 127 with a folding curvature can also be provided between the bridge section 130 and the two spring sections 110, 120. The folding segment 117, 128 can connect one spring leg 113, 123, which faces the bridge section 130, to the arc segment 131. The radius of curvature of the arc segment 131 can be smaller than the folding curvature of the folding segment 117, 127. Preferably, the arc segment

[0090] 131 and the folding segments 117, 127 are each curved in opposite directions to each other, so that the base body 101 can extend alternately in or against the closure direction VR along the width direction BR. In this way, the extension of the base body 101 can form a kind of labyrinth for the magnetic flux in the width direction BR.

[0091] Figure 1 also shows locking segments 118, 128, which extend along the width direction BR opposite the contact surface 111, 121. The function of these locking segments 118, 128 can be clarified in particular by referring to the illustrations of the locking device 100 in the locked position P2. Figures 2, 5, and 6 show in particular that the locking segments 118, 128 can prevent the spring arm 112, 122 from returning from the locked position P2 to the relaxed position PO by limiting the deformation of one of the spring arms 112, 122 relative to the other spring arm 113, 123 by blocking the relative movement.

[0092] The spring sections 110, 120 can each have a guide segment 119, 129 on their contact surfaces 111, 121 to guide the spring section 110, 120 against the corresponding counter-contact surfaces 511, 512 during assembly until the locking position P2 is reached. For example, a tapering of the cross-section at an end region in the locking direction VR can facilitate the insertion of the locking element 100 into the stator slot 510. Furthermore, the spring forces generated by the locking element 100 can also produce a clamping force in the locking direction VR in the locking position P2, as can be seen in particular in Figures 2 to 6. For example, the clamping force can be transmitted via a contact surface 103 to a counter-contact surface 513 in the stator slot 510.For example, in the locking position P2, windings 550 in the stator slot 510 can be subjected to a holding force in the locking direction VR.

[0093] Figures 7 and 8 show another embodiment of the closure device 100. This closure device 100 has a similar configuration to the closure device 100 described previously with reference to Figures 1 to 6. In particular, in this embodiment as well, the base body 101 is made in one piece from a bent sheet of steel. Therefore, the following section primarily describes the differences between the two configurations.

[0094] The spring sections 110, 120 each have two spring legs 112, 113, 122, 123, which are preferably connected in pairs via a bending leg with a bending radius. Unlike in the previous embodiment, the bending radius is selected such that the respective spring legs 112, 113, 122, 123 of a spring section 110, 120 extend almost perpendicularly to each other. The locking element 100 also has the bridge section 130, which surrounds the connection gap 140 in the locking direction VR. The two spring sections 110, 120 are directly connected to each other via a substantially V- or U-shaped arc segment 131, which extends with a curvature opposite to the locking direction VR. The spring sections 110, 120 each have a folding segment 117, 127 which extends simply folded into the spring clearance 115, 125.Preferably, the folded segment 117, 127 extends in the closed position P2, in particular, to the contact with the bending leg, which connects the spring legs 112, 113, 122, 123 of the same spring section 110, 120. The spring leg 112, 122 and the folded segment 117, 127 can thus align and guide magnetic field lines in the radial direction RR. Figure 7 shows exemplary compressive forces DK occurring in the stator slot 510, which result in the closed position P2 from the contact of the locking element 100 in the stator slot 510. This shows that the contact surface 103 for transmitting a clamping force to a counter-contact surface 513 of the windings 550 is arranged on the spring leg 113, 123 and thus, unlike in the embodiment of figures 1 to 6, acts on an edge area in the middle of the windings 550 instead of a central area of ​​the windings 550.

[0095] Figure 9 shows another embodiment of the closure device 100. Here, the closure device 100 has a similar geometry to the closure device 100 described previously with reference to Figures 7 and 8. Unlike before, however, the base body 101 is multi-part and made of different materials.

[0096] The base body 101 comprises two separate sub-base bodies 106, 107, each of which includes one of the two spring sections 110, 120 and each surrounds a portion of the connection clearance 140. In particular, the sub-base bodies 106, 107 each extend from the spring section 110, 120 with sub-bridge sections 1301, 1302, in order to reproduce the shape of the curved arc 131 when assembled. The sub-bridge sections 1301, 1302 each have at least one longitudinal leg extending in the locking direction VR and a bending leg with a radius of curvature. Unlike in Figures 7 and 8, the cross-section of the partial bridge sections 1301 and 1302 does not form a continuous curved arc 131, but rather the partial base bodies 106 and 107 are separated by an (air) gap 134. Preferably, the partial base bodies 106 and 107 can be bent from a U-shaped steel profile and can thus exhibit magnetic properties.

[0097] The base body 101 further comprises an I-, L-, or T-shaped non-magnetic stabilizing body 108. Preferably, the stabilizing body 108 can have a longitudinal leg 1082 and a transverse leg 1083 extending transversely and arranged centrally thereto. For example, the stabilizing body 108 can be made of plastic. In the closed position P2, the stabilizing body 108 is arranged between the partial base bodies 106, 107 in the connection space 140. Preferably, the longitudinal leg 1082 can be arranged here. In particular, the sections of the bridge segment 130 are each in planar contact with the stabilizing body 108 in order to achieve mutual support of the spring forces of the spring sections 110, 120. Preferably, the stabilizing body 108 can be force-fitted to the partial base bodies 106, 107.Alternatively or additionally, the parts of the multi-part base body 101 can also be connected to one another by an adhesive or positive-locking connection. The spring legs 113, 123 preferably also bear against the stabilizing body 108 in a planar contact. In particular, the spring legs 113, 123 bear against a partial surface of the transverse leg 1083 of the stabilizing body 108. A surface extending on the opposite side of the partial surface can thereby form an electrically insulating surface for bearing on winding wires 551 of the winding 500.

[0098] Figures 13 and 14 further show the resulting curves for the radial magnetic flux along the lateral direction BR for the different embodiments. Figure 13 shows a rotor 500 in which the slot axis is aligned with the magnetic field direction MFR. Figure 14, on the other hand, shows a rotor 500 in which the slot axis is rotated 90 degrees relative to the magnetic field axis.

[0099] Figures 13 and 14 show only moderate stray fluxes and high pulse amplitudes in the air gap for the embodiment depicted on the left in Figures 1 to 6. In contrast, the embodiment depicted on the right in Figures 7 and 8 exhibits strong stray fluxes but low pulse amplitudes in the air gap. The embodiment depicted in the center in Figures 9 to 12, however, shows low stray fluxes but high pulse amplitudes in the air gap.

[0100] Another aspect of the invention relates to a stator 500 for an electric motor, which has a rotor. Figures 2 to 14 show different embodiments of such a stator 500 according to the invention.

[0101] The stator 500 extends along a longitudinal axis LA with a stator body

[0102] 501. This can be seen, for example, in Figures 3 and 4. The stator body 501 has a plurality of stator slots 510 arranged evenly over a circumferential surface 502 for receiving windings 550. The stator slots 510 extend along the longitudinal axis LA and in a slot direction SR from the circumferential surface 502 into the stator body 501. This is shown, for example, in Figures 2, 5, and 9. Preferably, the stator slots 510 extend between adjacent stator teeth 503. The tooth flanks of the stator teeth 503 have mating surfaces 511 and 512. Figure 2 shows, by way of example, a preferred embodiment of the stator teeth 503, in which continuous tooth openings 504 extending along the longitudinal axis LA are arranged centrally in the stator tooth 503.

[0103] In Figures 2 to 4 and 7 to 14, the stator 500 is shown in a configuration with an external rotor (not shown in detail), where the circumferential surface 502 is an outer surface of the stator 500. In Figures 5 and 6, however, the stator 500 is shown in a configuration with an internal rotor (not shown in detail), where the circumferential surface 502 is an inner surface of the stator 500.

[0104] According to the invention, the stator slots 510 are each closed by the closing means 100 in the closing direction VR. Preferably, the closing means 100 can be arranged at the same height as the tooth openings 504 in the stator slots 510. Preferably, the stator slots 510 can have a receiving opening with a slot opening cross-section that corresponds at least partially to the cross-section of the closing means 100 in the closed position P2. Preferably, the slot opening cross-section in the width direction BR has a smaller extent than the closing means 100 in the relaxed position PO.

[0105] The stator 500 further comprises windings 550 made of winding wires 551. The winding wires 551 can be inserted into slot inserts 540 in the stator slots 510 for electrical insulation. Preferably, the ends of the slot inserts 540 can overlap at the circumferential surface 502. This is shown by way of example in Figures 2 to 14. Preferably, the overlap area thus formed can constitute the mating contact surface 513 for fastening the windings 550 in the stator slots 510. This has the advantage that the fastening means 100 are simultaneously electrically insulated from the windings 550. In the embodiment shown in Figure 9, this is not necessary, since the locking means 100 has an electrically insulating stabilizing body 108, with which the locking means 100 can rest on the slot inserts 540 without the risk of an electrical short circuit.

[0106] Another aspect of the invention relates to methods for closing the stator slots 510 with the aforementioned closing means 100.

[0107] In the case of the multi-part locking device 100 from Figure 9, the two partial base bodies 106, 107 are first inserted into the stator slot 510 along the longitudinal direction LR such that the partial base bodies 106, 107 are arranged in the stator slot 510 between the opposing mating surfaces 511, 512. In particular, the partial base bodies 106, 107 are aligned in the lateral direction BR and partially enclosing the connection gap 140. This process step is shown by way of example in Figure 10A. In a further step, the stabilizing body 108 is also inserted in the longitudinal direction LR into the connection gap 140 enclosed by the partial base bodies 106, 107. This is shown by way of example in Figures 10B, 11 and 12.The stabilizing body 108 preferably has an insertion tip 1081 at one end in the longitudinal direction LR, which facilitates the insertion or sliding of the stabilizing body 108 between the two partial base bodies 106, 107. The insertion of the stabilizing body 108 can be carried out along two directions, as can be seen from the insertion directions indicated in Figures 11 and 12. The stabilizing body 108 is then brought into contact with the partial base bodies 106, 107, at least partially, in the connection space 140, thus moving the locking means 100 into the locking position P2, since the partial base bodies 106, 107 are thereby expanded and elastically deformed, and spring forces are generated on the opposing contact surfaces 511, 512 of the stator slot 510.

[0108] In the case of the one-piece locking devices 100 from Figures 2 to 8, the locking device 100 is first elastically deformed at least at one of the spring sections 110, 120 in order to move the locking device 100 from the relaxed position PO to an assembly position by applying assembly forces. The deformed locking device 100 is then inserted in the assembly position into the stator slot 510 along the locking direction VR or along the longitudinal direction LR. By removing the assembly forces, the locking device 100 can be moved from the assembly position to the locking position P2, whereby the deformations elastically return to their original shape until a planar contact between the contact surfaces 111, 121 and the opposing contact surfaces 511, 512 of the stator slot 510 is achieved.

[0109] The preceding explanation of the embodiments describes the present invention solely by way of examples. Naturally, individual features of the embodiments can be freely combined with one another, provided this is technically feasible, without departing from the scope of the present invention.

[0110] Reference symbol list

[0111] Closure element 100 Base body 101 Contact surface 103 Partial base body 106, 107 Stabilizing body 108 Insertion tip 1081 Longitudinal leg 1082 Transverse leg 1083 First spring section 110 First contact surface 111 Spring leg 112, 113, 122, 123 Spring clearance 115, 125 Folding segment 116, 117, 126, 127 Securing segment 118, 128 Guide segment 119, 129 Second spring section 120 Second contact surface 121 Bridge section 130 Partial bridge sections 1301, 1302 Arc segment 131 Air gap 134 Connection clearance 140

[0112] Stator 500

[0113] Stator body 501

[0114] Circumferential area 502

[0115] Stator tooth 503

[0116] Tooth opening 504

[0117] Stator slot 510 first mating surface 511 second mating surface 512

[0118] Counter contact surface 513 Slot insert 540

[0119] 550 windings

[0120] Winding wire 551

[0121] Latitude BR

[0122] Pressure force DK

[0123] Longitudinal axis LA

[0124] Longitudinal direction LR

[0125] Magnetic field direction MFR

[0126] Relaxation position PO

[0127] Locking position P2 radial direction RR

[0128] Slot direction SR

[0129] Closure direction VR

Claims

Claims 1. Closing means (100) for closing a stator slot (510) of a stator (500) of an electric motor in a closing direction (VR), comprising a base body (101) which has a cross-section continuous along a longitudinal direction (LR) and a ferromagnetic material, characterized in that the cross-section has - a first spring section (110) with a first contact surface (111 ) for planar contact with a first counter-contact surface (511 ) of the stator slot (510), and - a second spring section (120) with a second contact surface (121) for planar contact with a second counter-contact surface (512) of the stator slot (510), wherein the second contact surface (121) is oriented opposite to the first contact surface (111), wherein the first spring section (110) and the second spring section (120) each have at least one spring clearance (115, 125) between two spring legs (112, 113, 122, 123) for elastic deformation of the spring sections (110, 120) from a relaxed position (PO) to a closed position (P2) when closing the stator slot (510) to generate spring forces in a lateral direction (BR) transverse to the longitudinal direction (LR) via the two contact surfaces (111, 121) onto the counter-contact surfaces (511, 512), and the The cross-section also has a connection space (140) between the two spring sections (110, 120) which is free of ferromagnetic material.

2. Locking means (100) according to claim 1, wherein the spring sections (110, 120) are each arranged at opposite ends of the cross-section in the lateral direction (BR) in order to exert opposing spring forces in the lateral direction (BR) on the opposing contact surfaces (511, 512) in the closed position (P2) via the two contact surfaces (111, 121). 512) to produce, wherein preferably the locking means (100) extends between the contact surfaces (111 , 121 ) in the width direction (BR), and wherein at least the spring sections (110, 120) have the ferromagnetic material.

3. Closure means (100) according to claim 1 or claim 2, wherein the cross-section further comprises a bridge section (130) which connects the two spring sections (110, 120) and at least partially surrounds the connection clearance (140), wherein the bridge section (130) extends between the two spring sections (110, 120) along the width direction (BR) with an arc segment (131) having an arc curvature, wherein the arc segment (131) is preferably U- or V-shaped, and wherein the arc segment (131) preferably extends with a curvature in or against the closure direction (VR).

4. Closure means (100) according to one of claims 1 to 3, wherein the connection space (140) is free of material and is preferably designed as an air gap.

5. Closure means (100) according to one of claims 1 to 4, wherein the base body (101) is formed in one piece, wherein preferably the base body (101) is a bent part, or wherein the base body (101) is formed in multiple parts, wherein preferably the base body (101) has at least one ferromagnetic part-base body (106, 107) with the spring sections (110, 120).

6. Closure means (100) according to one of claims 1 to 3, further comprising a stabilizing body (108) made of a non-ferromagnetic material, which is arranged between the two spring sections (110, 120) and preferably in the connection space (140), wherein the stabilizing body (108) preferably has a T-profile shape.

7. Closure means (100) according to claims 5 and 6, wherein the base body (101) is formed in multiple parts and the multi-part base body (101) has two separate partial base bodies (106, 107), each of which has at least one of the two spring sections (110, 120) and surrounds at least a part of the connection clearance (140), wherein the partial base bodies (106, 107) preferably have an identical material, and wherein the partial base bodies (106, 107) are separated from each other in cross-section by a gap (134) and are each arranged in contact with the stabilizing body (108) in order to support the spring forces against each other on the stabilizing body (108).

8. Locking means (100) according to one of the preceding claims, wherein the spring sections (110, 120) are identical to each other and are preferably arranged mirrored to each other in the width direction (BR) with respect to the connection clearance (140), and wherein the two spring legs (112, 113, 122, 123) are aligned almost parallel to each other in the locking position (P2) in order to specify preferred paths for the course of magnetic fields generated with the stator (500).

9. Locking means (100) according to one of the preceding claims, wherein the contact surfaces (111 , 121 ) or the spring legs (112, 113, 122, 123) with the contact surfaces (111 , 121 ) are each arranged inclined with respect to the locking direction (VR) in the direction of the connection clearance (140) in order to define a wedge angle, and wherein the cross-section has an extent in the width direction (BR) which increases along the locking direction (VR).

10. Closure means (100) according to one of the preceding claims, wherein at least one of the spring sections (110, 120) has at least one fold segment (116, 117, 126, 127) with a fold curvature, wherein the at least one fold segment (116, 117, 126, 127) extends away from one of the spring legs (112, 113, 122, 123), and wherein preferably the spring section (110, 120) has at least one folded segment (116, 117, 126, 127) which extends into the spring clearance (115, 125) and preferably extends into the spring clearance (115, 125) in multiple folds.

11. Locking means (100) according to one of the preceding claims, wherein at least one of the spring sections (110, 120) has a locking segment (118, 128) which extends in the width direction (BR) opposite to or towards the contact surface (111, 121) in order to limit deformation of the spring leg (112, 113, 122, 123) to return to the relaxation position (PO) in the locked position (P2).

12. Locking means (100) according to one of the preceding claims, wherein at least one of the spring sections (110, 120) has a guide segment (119, 129) on the contact surface (111, 121) to guide the spring section (110, 120) into the locking position (P2) contacting the corresponding counter-contact surface (511, 512) during assembly.

13. Locking means (100) according to one of the preceding claims, wherein the base body (101) further comprises a contact surface (103) oriented in the locking direction (VR) in order to transfer force components of the generated spring forces in the locking direction (VR) via the contact surface (103) to a counter-contact surface (513) in the locking position (P2) for a radial fixing of windings (550) in the stator slot (510).

14. Method for closing a stator slot (510) of a stator (500) of an electric motor in a closing direction (VR), characterized by Providing a closure means (100) according to any one of the preceding claims 1 to 6 and 8 to 13, Bringing the locking device (100) from the relaxed position (PO) into an assembly position by applying assembly forces to elastically deform at least one of the two spring sections (110, 120) in the lateral direction (BR) of the locking device (100), Inserting the deformed closure element (100) in the assembly position into the stator slot (510) along the closure direction (VR) or the longitudinal direction (LR), and Bringing the locking means (100) from the mounting position to the locking position (P2) by removing the mounting forces and elastically deforming both spring sections (110, 120) until a planar contact of the contact surfaces (111 , 121 ) with the counter-contact surfaces (511 , 512) of the stator slot (510) is achieved.

15. Method for closing a stator slot (510) of a stator (500) of an electric motor in a closing direction (VR), characterized by Providing the sealing means (100) according to claim 7, Inserting the two partial base bodies (106, 107) into the stator slot (510) along the longitudinal direction (LR), so that the partial base bodies (106, 107) are arranged in the stator slot (510) in the width direction (BR) and partially enclosing the connection clearance (140) between the opposing counter-contact surfaces (511, 512), Inserting the stabilizing body (108) in the longitudinal direction (LR) into the connection space (140) enclosed by the partial base bodies (106, 107), Bringing the locking means (100) into the locking position (P2) by at least partially bringing the stabilizing body (108) into contact with the partial base bodies (106, 107) in the connection space (140) in order to elastically deform the partial base bodies (106, 107) and to generate spring forces on the opposing contact surfaces (511, 512) of the stator slot (510).

16. Stator (500) for an electric motor with a rotor, comprising a stator body (501) extending along a longitudinal axis (LA), which has stator slots (510) arranged uniformly over a circumferential surface (502) for receiving windings (550), wherein the stator slots (510) extend along the longitudinal axis (LA) and in a Slot direction (SR) extend from the circumferential surface (502) in the stator body (501 ), characterized in that at least one of the stator slots (510) has a closing means (100) according to one of claims 1 to 13 in order to close the stator slots (510) at least on the circumferential surface (502) of the stator body (501 ) in the closing direction (VR).

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