Stator and method for producing a stator

Abstract

The invention relates to a stator (1) of an electric machine, having an electrical connection device (3) for contacting winding wires (4) of the stator protruding axially from the stator, wherein the electrical connection device (3) has multiple contact tabs (5) which are each penetrated by at least one of the winding wires (4) protruding axially from the stator (1), and the electric contact between a contact tab (5) and a winding wire (4) is produced by means of a hot crimping method, wherein at least one first of the contact tabs (11) is penetrated by at least two winding wires (4) protruding axially from the stator (1) and the electric contact between said first contact tab (11) and the two winding wires (4) is produced by means of a hot crimping method.

Description

[0001] P241000

[0002] - 1 -

[0003] Stator and method for manufacturing a stator

[0004] The present invention relates to a stator of an electric machine with an electrical connection device for contacting winding wires of the stator that project axially from the stator, wherein the electrical connection device has a plurality of contact tabs, each of which is penetrated by at least one of the winding wires projecting axially from the stator, and the electrical contact between a contact tab and a winding wire is produced by a hot crimping process. The invention further relates to a method for manufacturing a stator.

[0005] Various stator designs and manufacturing processes are known in the art, particularly for use in electrical machines such as electric motors or generators. Stators typically consist of a core surrounded by winding wires, which, when current flows through them, generate a magnetic field that enables the rotor to rotate. The electrical connection of the winding wires to the external circuit is usually made by special connecting elements, such as contact tabs, which require complex attachment to the wires.

[0006] A major problem with known stators lies in the complex and time-consuming process of creating the electrical connections between the winding wires and the contact points. Particularly with dense winding packages where the wires are closely spaced, ensuring the necessary accessibility to the winding wires for a reliable electrical connection is challenging. This complicates the use of tools such as crimping pliers and increases the likelihood of assembly errors. Furthermore, existing methods often require multiple individual steps for insulating, positioning, and connecting the winding wires, extending production time and increasing costs. P241000

[0007] - 2 -

[0008] Furthermore, the connecting elements used in conventional methods, especially when individually attached to the winding wires, tend to be subject to increased mechanical stress, which can lead to damage or breakage of the winding wires. This impairs the service life and reliability of the stator. Another problem is that the electrical connections often exhibit high contact resistances, resulting in energy losses and reducing the overall efficiency of the electric machine. The stability of the electrical connections under thermal loads, such as those encountered during the operation of electric motors, is also insufficient in many cases, which can lead to premature contact degradation.

[0009] It is therefore an object of the invention to avoid or at least reduce the problems known from the prior art and to provide an improved stator. It is also an object of the invention to realize an optimized manufacturing process for a stator.

[0010] This problem is solved by a stator of an electric machine with an electrical connection device for contacting winding wires of the stator that protrude axially from the stator, wherein the electrical connection device has a plurality of contact tabs, each of which is penetrated by at least one of the winding wires that protrude axially from the stator, and the electrical contact between a contact tab and a winding wire is produced by means of a hot crimping process, wherein at least one first of the contact tabs is penetrated by at least two winding wires that protrude axially from the stator and the electrical contact between this first contact tab and the two winding wires is produced by means of a hot crimping process.

[0011] This stator offers the advantage that the use of a common contact tab for at least two winding wires reduces the number of contact points, thus decreasing component complexity and material requirements. Furthermore, the electrical contact is reliably established through hot crimping, resulting in a durable and stable electrical connection. P241000

[0012] - 3 - is ensured. Another advantage is that the shared contacting of several wires facilitates access to the contact tab for the crimping tool, which reduces assembly time and makes the production process more efficient.

[0013] First, the individual elements of the claimed invention are explained in the order in which they are mentioned in the claim set, and subsequently, particularly preferred embodiments of the invention are described.

[0014] Electrical connection device

[0015] For the purposes of this patent application, a connecting device is a device or assembly that serves to establish electrical contact between the winding wires extending axially from a stator of an electrical machine and other electrical components, in particular power electronics.

[0016] The connection device preferably comprises several contact tabs designed to receive the axially protruding winding wires. The winding wires are guided through the contact tabs and firmly connected to them using a hot crimping process. This process ensures a robust mechanical connection while simultaneously guaranteeing optimal electrical conductivity. The design of the contact tabs allows for simplified access to the crimping tool, which facilitates and speeds up the assembly process.

[0017] The connecting device can be made of various materials, preferably copper, copper alloys, or aluminum. Aluminum offers the advantage of lower weight combined with good electrical conductivity, which is particularly important for applications with high weight-efficiency requirements. Aluminum can also be a more cost-effective alternative to copper, especially in applications with large material volumes. P241000

[0018] - 4 -

[0019] Regarding functionality, the connection device can advantageously be designed for multi-phase connections, particularly for a three-phase current supply to the stator winding. Furthermore, the connection device can also include one or more busbars that are electrically insulated from each other to separate the phases of the winding wires and prevent short circuits. These busbars can be either monolithic with the contact lugs or assembled modularly to allow for flexible adaptation to different machine configurations. A one-piece construction is preferred to increase the reliability of the electrical connection and the mechanical stability. Coatings, such as a corrosion protection layer or a thermally conductive coating, can also preferably be applied to improve the durability and resistance of the connection device.

[0020] For the purposes of this patent application, a winding wire is an electrically conductive element used in an electric machine to generate the electromagnetic field within the stator. The winding wire is preferably made of a wire material that advantageously exhibits high electrical conductivity to enable current flow with minimal losses. The winding wire is preferably made of copper, as copper possesses excellent conductivity and is characterized by good mechanical deformability. In certain embodiments, the winding wire can also be made of aluminum to reduce the weight of the stator, with the electrical conductivity of the material being designed according to the requirements of the machine.

[0021] The winding wire is preferably surrounded by an insulating layer to ensure reliable electrical isolation of the individual windings and to prevent short circuits between adjacent wire turns. An insulating material such as varnish or plastic is preferably used for this purpose, which can withstand both thermal and mechanical stresses during machine operation. The winding wires can preferably be round, as these are easy to process and offer flexibility in arrangement. P241000

[0022] - 5 -

[0023] Alternatively, rectangular or flattened wire shapes can be used to achieve a higher packing density in the stator, resulting in increased machine performance.

[0024] For the purposes of this patent application, a hot crimping process is a method for the electrical and mechanical joining of conductors, in which a permanent, secure, and low-resistance connection between the elements to be contacted is created by targeted heating and mechanical compression. In the hot crimping process, the winding wires to be joined and the contact tab are heated to a temperature sufficient to plastically deform the tab material and, if applicable, any coating.

[0025] Subsequently, with the simultaneous application of heat, the tab is mechanically pressed together with the winding wires contained within it, creating a firm mechanical and electrical connection.

[0026] The function of the hot crimping process is therefore primarily to ensure both an electrically and mechanically stable connection between the components. The heat treatment makes the contact plate material softer and more malleable, allowing it to conform optimally to the surface of the winding wires. Simultaneously, the mechanical crimping ensures that the wires are firmly enclosed within the contact plate. This results in a durable connection that, due to the plastic deformation of the material, can withstand mechanical stresses. Furthermore, the increased contact area created by crimping minimizes electrical resistance, ensuring efficient current transmission.

[0027] The hot crimping process preferably begins with positioning the winding wires in the contact tab. The tab is then advantageously heated locally or completely so that the material becomes malleable. Subsequently, the tab is mechanically crimped by using a tool – preferably crimping pliers – to firmly press the tab onto the wires. The P241000

[0028] - 6 -

[0029] The process ends with the cooling of the contact point, at which point the connection achieves its final strength.

[0030] Possible embodiments of the hot crimping process include various methods for heat application. Advantageously, the heat can be generated inductively by using an electromagnetic field to directly heat the contact tab. Alternatively, heating can be achieved by resistance heating, whereby current is passed through the tab to heat it. In another embodiment, heating can be effected by a heating element applied to the contact tab.

[0031] Contact tab

[0032] For the purposes of this patent application, a contact tab is a component of the electrical connection device, which serves to establish an electrical connection between the winding wires of the stator and the connection device, in particular a busbar of the connection device. The contact tab preferably has a flat, strip-shaped structure through which one or more winding wires projecting axially from the stator are passed in order to subsequently be electrically contacted by means of a hot crimping process.

[0033] Regarding its construction, the contact tab can preferably be made of an electrically conductive material such as copper or aluminum, which offers good conductivity and high thermal resistance. Materials that withstand both the high temperatures of the hot crimping process and the mechanical stresses during motor operation are advantageous. The contact tab can either be formed integrally with the busbar or welded or attached to it as a separate element. A one-piece, monolithic construction offers the advantage of improved electrical conductivity and increased mechanical stability, as there are no additional connection points that could potentially be prone to failure. Structurally, the contact tab can be flat or angled to ensure optimal adaptation to the spatial conditions of the stator and the position of the winding wires. P241000

[0034] - 7 -

[0035] Advantageous embodiments of the invention

[0036] According to an advantageous embodiment of the invention, the electrical connection device may have at least one first busbar that is axially spaced from the stator at least partially along a circular contour, from which at least one contact tab, preferably a plurality of contact tabs, and most preferably all contact tabs, extend radially outwards. Advantageously, the axial spacing of the busbar from the stator allows for better spatial separation of the electrical contacts, which reduces the risk of short circuits between the winding wires. Furthermore, the radial orientation of the contact tabs achieves optimal placement of the electrical connections, resulting in improved accessibility for assembly tools and increased flexibility in integrating the stator into different designs of electrical machines.

[0037] For the purposes of this patent application, a busbar is therefore a component of the electrical connection device that serves to establish electrical connections between the winding wires of the stator and the switching system of the electric machine. The busbar is electrically conductive and runs along a specific contour at a defined distance from the stator, receiving and conducting the electrical currents from the winding wires protruding axially from the stator.

[0038] Regarding its construction, the busbar is preferably made of a highly conductive material such as copper or aluminum to minimize electrical losses and ensure high current-carrying capacity. Advantageously, the busbar can be manufactured as a monolithic component that integrates contact tabs, or it can consist of several segments that are electrically insulated and mechanically connected. Possible embodiments include both flat, strip-shaped structures and profiled variants that allow for optimized current flow and mechanical fastening of the winding wires via the contact tabs. P241000

[0039] - 8 -

[0040] According to a further preferred embodiment of the invention, the electrical connection device may also include a second busbar axially spaced from the stator at least partially along a rib-like contour, and at least one third busbar axially spaced from the stator at least partially along a rib-like contour, wherein the first busbar, the second busbar, and the third busbar are electrically insulated from one another. The introduction of multiple electrically insulated busbars offers the advantage that different winding phases of the stator can be safely and separately routed without electrical flashovers or unwanted connections occurring.

[0041] Furthermore, according to another advantageous embodiment of the invention, at least the first contact lugs of the first busbar, which is penetrated by at least two winding wires projecting axially from the stator, can be formed at a first circumferential distal end of the first busbar. By arranging the contact lugs at the distal ends of the busbars, the structural integrity of the busbar is enhanced, as the contact is made at a mechanically stable point. This improves the reliability of the electrical connection and prevents damage to the winding wires due to mechanical stress. Moreover, this positioning further optimizes accessibility for assembly tools, thus simplifying the manufacturing process.

[0042] According to a further particularly preferred embodiment of the invention, at least one second contact tab is penetrated by at least two winding wires projecting axially from the stator, and the electrical contact between this second contact tab and the two winding wires is established by means of a hot crimping process. The use of a second contact tab for contacting two winding wires enables redundancy in the electrical connection, which increases the reliability of the overall system. By distributing the electrical load across multiple contact points, the service life is extended.

[0043] - 9 - the connection is extended and the risk of failure is reduced. In addition, the double contact can contribute to a more even current distribution within the stator, which improves the efficiency of the electric machine.

[0044] Furthermore, the invention can also be further developed such that the second contact tab of the first busbar, which is penetrated by at least two winding wires projecting axially from the stator, is formed at a second circumferential distal end of the first busbar. Positioning the second contact tab at a further distal end of the busbar offers the advantage of achieving a symmetrical distribution of the contact points. This results in a balanced mechanical load on the busbar and the winding wires, thereby improving the mechanical stability of the system. Moreover, this symmetrical arrangement simplifies manufacturing, as the positioning of the tabs is clearly defined and assembly errors are reduced.

[0045] In a preferred embodiment of the invention, the first contact tab and / or the second contact tab can also be formed integrally, particularly monolithically, with the first busbar. The integral or monolithic formation of the contact tabs with the busbar offers the advantage that no additional mechanical connections between the components are required. This reduces the number of potential sources of error and increases the reliability of the electrical connection. Furthermore, the monolithic design simplifies the manufacturing process, as fewer components need to be processed and assembled, which reduces production costs and shortens production time.

[0046] It can also be advantageous to further develop the invention such that only the first busbar has a first contact tab and / or second contact tab, each of which is penetrated by at least two winding wires projecting axially from the stator. The advantage of limiting the invention to one busbar with multiple contact tabs, each of which is penetrated by at least two winding wires, lies in the simplification of the electrical system. Reducing it to a single busbar facilitates manufacturing. P241000

[0047] - 10 - and reduces the space requirement, which is particularly advantageous in compact electric motors.

[0048] According to a further preferred embodiment of the invention, the two winding wires passing through the first contact tab can run parallel between their exit from the stator and the first contact tab and bear against each other at least partially, and / or the two winding wires passing through the second contact tab can run parallel between their exit from the stator and the second contact tab and bear against each other at least partially. The parallel routing of the winding wires between their exit from the stator and the contact tabs offers the advantage of uniform mechanical stress on the wires, which reduces the risk of wire breakage or damage. Furthermore, this arrangement facilitates the precise positioning of the wires in the contact tabs, which simplifies the manufacturing process and increases the reliability of the electrical connection.

[0049] Finally, the problem of the invention can also be solved by a method for manufacturing a stator of an electrical machine, comprising the following steps:

[0050] • Provision of a stator with a plurality of winding wires projecting axially from the stator;

[0051] • Provision of an electrical connection device for contacting the axially protruding winding wires of the stator, wherein the electrical connection device has a plurality of contact tabs, each of which can be penetrated by at least one of the axially protruding winding wires from the stator, and wherein at least one of the contact tabs can be penetrated by at least two axially protruding winding wires from the stator; P241000

[0052] - 11 -

[0053] Positioning of the electrical connection device so that the first contact tab is penetrated by at least two winding wires projecting axially from the stator;

[0054] • Establishing an electrical contact between the first contact tab and the two winding wires using a hot crimping process.

[0055] The described manufacturing process offers the advantage of simple and quick stator assembly, as the winding wires are inserted into the contact tabs without complex handling and securely connected using hot crimping. This reduces manufacturing time and minimizes the risk of assembly errors. Furthermore, the use of hot crimping creates a stable and durable electrical connection that is both mechanically robust and electrically efficient.

[0056] The invention will now be explained in more detail with reference to figures, without limiting the general concept of the invention.

[0057] It shows:

[0058] Figure 1 shows a stator with an electrical connection device in a perspective view,

[0059] Figure 2 shows a stator with an electrical connection device in a top view.

[0060] Figures 1 and 2 each show a stator 1 of an electric machine with an electrical connection device 3 for contacting winding wires 4 of the stator 1 that project axially from it. The electrical connection device 3 has a plurality of contact tabs 5, each of which is penetrated by at least one of the winding wires 4 projecting axially from the stator 1. The electrical contact between P241000

[0061] - 12 - a contact tab 5 and a winding wire 4 are produced using a hot crimping process. Figures 1-2 show the stator in its assembled state before hot crimping.

[0062] A first contact lug 11 is penetrated by at least two winding wires 4 projecting axially from the stator 1, and the electrical contact between this first contact lug 11 and the two winding wires 4 is established by a hot crimping process. In Figure 2, the first contact lug is located at approximately twelve o'clock. The connecting device 3 has a second contact lug 12, which is penetrated by at least two winding wires 4 projecting axially from the stator 1, and the electrical contact between this second contact lug 12 and the two winding wires 4 is also established by a hot crimping process. The second contact lug 12 is located at approximately six o'clock in Figure 2.

[0063] The electrical connection device 3 has a first busbar 7 that is axially spaced from the stator 1 at least partially along a circular contour 6, from which all contact lugs 5, 11, 12 extend radially outwards. Figures 1-2 also clearly show that the electrical connection device 3 has a second busbar 8 and a third busbar 9 that are axially spaced from the stator 1 at least partially along a spiral contour 6, wherein the first busbar 7, the second busbar 8, and the third busbar 9 are electrically insulated from each other.

[0064] The two winding wires 4 passing through the first contact lug 11 run parallel between their exit from the stator 1 and the first contact lug 11 and are in contact with each other at least partially. The same applies to the two winding wires 4 passing through the second contact lug 12, which run parallel between their exit from the stator 1 and the second contact lug 12 and are in contact with each other at least partially. P241000

[0065] - 13 -

[0066] It is clearly evident from Figures 1-2 that only the first busbar 7 has a first contact tab 11 and a second contact tab 12, each of which is penetrated by at least two winding wires 4 projecting axially from the stator 1.

[0067] The first contact lug 11 of the first busbar 7, which is penetrated by at least two winding wires 4 projecting axially from the stator 1, is formed at a first circumferential distal end 10 of the first busbar 7, while the second contact lug 12 of the first busbar 7, which is penetrated by at least two winding wires 4 projecting axially from the stator 1, is formed at a second circumferential distal end 13 of the first busbar 7. The first contact lug 11 and the second contact lug 12 are formed integrally, in particular monolithically, with the first busbar 7.

[0068] A method for manufacturing a stator 1 of an electrical machine, as sketched in Figures 1-2, may comprise the following steps. First, a stator 1 is provided with a plurality of winding wires 4 projecting axially from the stator 1, and an electrical connection device 3 is provided for contacting the winding wires 4 of the stator 1 projecting axially from the stator 1. The electrical connection device 3 has a plurality of contact tabs 5, each of which can be penetrated by at least one of the winding wires 4 projecting axially from the stator 1, and in which at least one of the contact tabs 11 can be penetrated by at least two winding wires 4 projecting axially from the stator 1.

[0069] The electrical connection device 3 is then positioned such that the first contact tab 11 is penetrated by at least two winding wires 4 projecting axially from the stator 1. Electrical contact is then established between the first contact tab 11 and the two winding wires 4 using a hot crimping process. P241000

[0070] - 14 -

[0071] It is understood that the second contact tab 12 can be treated in an analogous manner.

[0072] The invention is not limited to the embodiments illustrated in the figures. The foregoing description is therefore not to be considered limiting, but rather explanatory. The following claims are to be understood as meaning that a named feature is present in at least one embodiment of the invention. This does not preclude the presence of further features. Where the claims and the foregoing description define 'first' and 'second' features, this designation serves to distinguish between two similar features without establishing any hierarchy.

[0073] P241000

[0074] - 15 -

[0075] List of reference signs

[0076] I Stator 3 Connection device

[0077] 4 winding wires

[0078] 5 contact tabs

[0079] 6 Contour

[0080] 7 busbar 8 busbar

[0081] 9 busbar

[0082] 10 End

[0083] II Contact tab

[0084] 12 Contact tab 13 End

Claims

P241000 - 16 - Claims 1. Stator (1) of an electrical machine with an electrical connection device (3) for contacting winding wires (4) of the stator (1) projecting axially from the stator (1), wherein the electrical connection device (3) has a plurality of contact tabs (5), each of which is penetrated by at least one of the winding wires (4) projecting axially from the stator (1), and the electrical contact between a contact tab (5) and a winding wire (4) is produced by means of a hot crimping process, characterized in that at least one first of the contact tabs (11) is penetrated by at least two winding wires (4) projecting axially from the stator (1), and the electrical contact between this first contact tab (11) and the two winding wires (4) is produced by means of a hot crimping process.

2. Stator (1 ) according to claim 1 , characterized in that the electrical connection device (3) has at least one first busbar (7) which is axially spaced at least sectionally along a rice-like contour (6) from which at least one contact tab (5), preferably a plurality of the contact tabs (5), particularly preferably all contact tabs (5) extend radially outwards.

3. Stator (1 ) according to claim 1 or 2, characterized in that the electrical connection device (3) comprises a second busbar (8) axially spaced at least partially along a rice-like contour (6) from the stator (1 ) and at least one third busbar axially spaced at least partially along a rice-like contour (6) from the stator (1 ). P241000 - 17 - has a busbar (9) wherein the first busbar (7) and the second The busbar (8) and the third busbar (9) are electrically isolated from each other.

4. Stator (1 ) according to one of the preceding claims, characterized in that at least the first contact tabs (11 ) of the first busbar (7), which is penetrated by at least two winding wires (4) projecting axially from the stator (1 ), is formed at a first circumferential distal end (10) of the first busbar (7).

5. Stator (1 ) according to one of the preceding claims, characterized in that at least one second of the contact tabs (12) is penetrated by at least two winding wires (4) axially projecting from the stator (1 ) and the electrical contact between this second contact tab (11 ) and the two winding wires (4) is produced by means of a hot crimping process.

6. Stator (1 ) according to claim 5, characterized in that the second contact tab (12) of the first busbar (7), which is penetrated by at least two winding wires (4) projecting axially from the stator (1 ), is formed at a second circumferential distal end (13) of the first busbar (7).

7. Stator (1 ) according to one of the preceding claims, characterized in that the first contact tab (11 ) and / or the second contact tab (12) are formed in one piece, in particular monolithically, with the first busbar (7). P241000 - 18 - 8. Stator (1 ) according to one of the preceding claims, characterized in that only the first busbar (7) has a first contact tab (11 ) and / or second contact tab (12), each of which is penetrated by at least two winding wires (4) axially projecting from the stator (1 ).

9. Stator (1 ) according to one of the preceding claims, characterized in that the two winding wires (4) passing through the first contact tab (11) run parallel between their exit from the stator (1 ) and the first contact tab (11) and are at least partially in contact with each other and / or the two winding wires (4) passing through the second contact tab (12) run parallel between their exit from the stator (1 ) and the second contact tab (12) and are at least partially in contact with each other.

10. Method for manufacturing a stator (1 ) of an electrical machine, comprising the following steps: • Provision of a stator (1 ) with a plurality of winding wires (4) extending axially from the stator (1 ); • Provision of an electrical connection device (3) for contacting the winding wires (4) of the stator (1) projecting axially from the stator (1), wherein the electrical connection device (3) has a plurality of contact tabs (5), each of which can be penetrated by at least one of the winding wires (4) projecting axially from the stator (1), and wherein at least one of the contact tabs (11) can be penetrated by at least two winding wires (4) projecting axially from the stator (1); P241000 - 19 - • Positioning of the electrical connection device (3) such that the first contact tab (11) is penetrated by at least two winding wires (4) projecting axially from the stator (1); • Establishing an electrical contact between the first contact tab (11) and the two winding wires (4) by means of a hot crimping process.

Images