Electric machine with flexible electrical conductors and shaped insulation
By using a combination of flexible carbon nanotubes or graphene fibers and thermoplastic insulating sheaths, the winding technology problem of motor stator and rotor coils was solved, improving the power density of the motor and reducing its weight and cost.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- ROBERT BOSCH GMBH
- Filing Date
- 2021-01-25
- Publication Date
- 2026-06-09
AI Technical Summary
The existing stator and rotor coil winding technology of motors affects the power and efficiency of motors, and the traditional copper conductor has poor shape stability during bending, resulting in complex manufacturing and high cost.
Using flexible carbon nanotubes or graphene fibers as conductor materials and wrapping them with an insulating sheath made of thermoplastic synthetic materials, the plug-in windings are formed into a fixed shape by heating and cooling, reducing material usage and weight.
This improved the power density and fill factor of the motor, reduced weight and manufacturing costs, and simplified the manufacturing process.
Smart Images
Figure CN115298934B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to an electric motor having a rotor and a stator. The rotor and / or stator have plug-in windings composed of flexible electrical conductors and shaped insulators. The invention further relates to a method for manufacturing electrical conductor elements used in the plug-in windings of the rotor and / or stator of the electric motor.
[0002] The present invention also relates to a forming apparatus for manufacturing an electrical conductor element used as a plug-in winding of a rotor and / or stator of an electric motor. Background Technology
[0003] In the transition from fossil fuels to renewable energy, vehicle drive systems have become increasingly important. In recent years, stricter laws regulating vehicle emissions have accelerated the development of alternative drive systems.
[0004] Here, the development of pure electric drive systems plays an increasingly important role in the development of long-lasting drive systems for vehicles. Automakers are further developing electric motors to provide an efficient and everyday-use alternative to internal combustion engines.
[0005] The winding technology of the coil windings used in the stator and rotor of electric motors, in particular, significantly affects the power and efficiency of the motor. Therefore, the coil winding method is also a key focus in the manufacture and development of high-power coil windings for motors used in vehicle drive systems.
[0006] As is well known, the stator windings of an electric motor are constructed using a plug-in technique. Insulated conductor elements are inserted into the stator body. Then, the inserted conductor elements are interconnected to form the corresponding stator windings. To obtain the desired shape for each conductor element, the insulated conductor elements are bent into their desired shapes through multiple bending processes before being inserted into the stator body. Summary of the Invention
[0007] The electric motor according to the invention particularly has an optimized power density. The motor includes a rotor and a stator, wherein the rotor and / or stator have plug-in windings. The plug-in windings include a plurality of rigid, insulated electrical conductor elements, wherein the conductor elements are arranged in slots in the stator or rotor. Here, the ends of the conductors protrude from the slots, wherein the conductor ends of the conductor elements are respectively connected to the conductor ends of other conductor elements to form an electrical plug-in winding. Each conductor element has an insulating sheath. Furthermore, each conductor element has a plurality of conductive, flexible fibers, particularly flexible fiber conductor strips. A plurality of fibers are surrounded by a flexible insulating sheath. Furthermore, the insulating sheath is configured such that it imparts a rigid shape to the electrical conductor element. Thus, the insulating sheath is particularly configured as a flexible or sleeve-shaped sheath, and the flexible fibers are arranged within the insulating sheath. Preferably, the insulating sheath allows for the construction of the conductor elements with a minimized volume and a maximized fill power.
[0008] The flexible fibers are preferably composed of carbon nanotubes or graphene. Carbon nanotubes or graphene have exceptionally high electrical conductivity and low density. Furthermore, the use of carbon nanotubes or graphene allows for exceptionally high filler density of the conductor elements, thereby achieving a particularly high filler factor in the motor. Therefore, the power density of the motor can be increased. In addition, due to the high conductivity of the conductor, material usage can be reduced, which, together with the lower conductor density, results in a lighter motor and lower manufacturing costs. Alternatively, metal fibers or conductive polymers and yarns can be used as the conductors, which can become conductive, for example, by doping.
[0009] In particular, unlike the plug-in windings used to date, numerous conductive, flexible fibers are used instead of the bent copper conductor, which retains its shape after the bending process. By abandoning the copper plug-in windings known from the prior art, the shape of the conductor element is therefore determined not by the flexible fibers, but by a rigid insulating sheath. Therefore, the plastic forming characteristics, as previously seen in copper conductors, are not a necessary prerequisite when selecting conductor materials. This also allows for the use of flexible electrical conductors, i.e., fibers, thereby significantly expanding the selection of materials for electrical conductors. This particularly enables the use of the previously described low-density materials, thereby reducing the overall weight of the motor.
[0010] Furthermore, by using flexible fibers, a higher fill factor can be achieved in motors. Typically, flexible materials are characterized by a low modulus of elasticity and high deformability due to small forces and moments. Generally, the weight of the flexible fibers themselves is sufficient to deform the material.
[0011] Here, flexible fibers lack a rigid shape and therefore cannot be imprinted into a defined, predetermined shape through a bending process. Therefore, they are arranged within a shaped insulating sheath to maintain a fixed shape. In contrast, rigid materials are defined in such a way that their fixed shape can be retained after the forming process without the need for additional components or material support. Significant changes in shape can only be achieved by using higher forces. Here, the conductor's own weight is insufficient.
[0012] A preferred embodiment of the invention includes: the insulating sheath is heat-shrinkable onto a plurality of flexible fibers; the insulating sheath tensions the plurality of flexible fibers, especially conductor strips, within the insulating sheath; the insulating sheath is made of a thermoplastic synthetic material, especially polyetheretherketone; the insulating sheath is made of an insulating material having a negative coefficient of thermal expansion; each conductor element is configured in a U-shape or I-shape and has a quadrilateral, especially rectangular, cross-section; the flexible fibers, especially conductor strips, of each conductor element extend from the corresponding insulating sheath at the two conductor ends of the corresponding conductor element for electrically connecting the corresponding conductor element to other conductor elements among the conductor elements.
[0013] The insulating sheath is advantageously heat-shrinkable onto numerous flexible fibers. This enables simple and low-cost installation of the electrical conductor element. Particularly advantageous is that the insulating sheath is a shrink tubing. This allows for simple and reliable shaping of the electrical conductor element.
[0014] Of particular advantage is that the insulating sheath tensions numerous flexible fibers, especially conductor strips. This creates tension within the insulating sheath. This facilitates the tight encapsulation of the flexible fibers within the electrical conductor element. This advantageously allows for the achievement of the small volume and high packing density described above.
[0015] Preferred insulating sheaths are made of thermoplastic synthetic materials, particularly polyetheretherketone (PEEK). PEEK is a thermoplastic synthetic material suitable for use as insulating sheaths for electrical conductor elements in motors due to its high-temperature resistance and resistance to high-energy electromagnetic waves. Unlike other plastics, PEEK has a relatively high melting point, thus remaining undamaged even at the high operating temperatures of motors. Furthermore, PEEK's thermoplastic deformability makes it particularly suitable for the personalized and flexible rigid shaping of electrical conductor elements. PEEK can, for example, be heated to become substantially rigid molded elements. This allows for the production of different geometries and sizes of conductor elements at relatively low cost. However, other thermoplastic materials are also conceivable, either already possessing a substantially rigid shape or capable of being hardened by processes, such as heat transfer.
[0016] In a preferred design, the insulating sheath is made of an insulating material with a negative coefficient of thermal expansion. This allows the insulating sheath to be easily and reliably applied to the fiber, which is then reliably held within the sheath. The heating of the conductor element is thus facilitated by the negative expansion (contraction) of the insulating sheath, which contributes to the more secure holding of the conductor element.
[0017] In one embodiment, each conductor element can be configured in a U-shape or an I-shape. Furthermore, it is preferable that the conductor elements have a quadrilateral, particularly rectangular, cross-section. This shape allows for easy interconnection of the individual conductor elements. U-shaped conductor elements are particularly preferred because the plug-in windings thus only need to be connected to each other at the ends of the rotor and / or stator, thereby reducing the motor's connection costs and, consequently, its manufacturing costs. Furthermore, this reduces the number of connection points in the rotor and / or stator, further reducing installation costs. Additionally, this allows for a reduction in the size of the motor housing, thereby further increasing the motor's power density.
[0018] Furthermore, the present invention relates to a method for improving the manufacture of plug-in windings for rotors and / or stators of electric motors. This method is used to manufacture substantially rigid, insulated electrical conductor elements used in the plug-in windings of rotors and / or stators of electric motors, particularly electric motors for electrically driven vehicles, and specifically includes the following steps:
[0019] First, a flexible fiber strip made of carbon nanotubes or graphene is wrapped around a tubular insulating sheath during the formation of the conductor element. The insulating sheath is preferably thermoplastically deformable. Next, the conductor element is arranged in a recess of a forming device. The recess thus shapes the conductor element. Then, the conductor element is heated in the recess of the forming device using at least one heating element. This heating continues until a temperature causes the insulating sheath to thermally shrink, particularly tighten. In this way, the fibers arranged within the insulating sheath are preferably tightly abutted against each other and tightly adhered to the insulating sheath. This achieves tight encapsulation of the fibers. After heating, the conductor element is cooled. Furthermore, the insulating sheath is preferably hardened by heating and / or cooling, so that the conductor element retains the shape predetermined by the recess. Here, the conductor element is formed using the insulating sheath. Unlike the known bending process of insulated copper conductors, this method shapes the conductor element not by bending, but by arranging the insulating sheath and flexible, conductive fibers in recesses constructed in the forming apparatus and by subsequently heating the insulating sheath. Here, the shape of the recesses substantially corresponds to the desired shape of the conductor element. In this method, the forming and insulation of the conductor are advantageously performed in a single process step, thereby reducing the number of process steps. Different shapes of conductor elements can be formed flexibly, quickly, and accurately using the method according to the invention. Thus, different geometries and sizes of conductor elements can be achieved by using different forming apparatuses. Advantageously, the insulating sheath is flexible before heat is introduced and can be deformed without damage without requiring high force. Here, the flexible insulating sheath does not retain its shape without external support. In the method according to the invention, the flexible insulating sheath is held in the desired shape by means of the forming recesses before heating. The insulating sheath is preferably sleeve-shaped or hose-shaped. Preferably, flexible fibers are guided through the sleeve-shaped or hose-shaped insulating sheath. The insulating sheath may also comprise multiple segments inserted along the direction of the recess and preferably directly adjacent to each other, enclosing the flexible fiber segments in a segmental manner. The segments are preferably connected to each other by a heating material. The insulating sheath is preferably made of a thermoplastic synthetic material, particularly polyetheretherketone (PEEK). The curing process, particularly by means of heating and cooling, can preferably be performed using passive temperature reduction. Here, for example, temperature reduction can be promoted simply by interrupting heat transfer. Alternatively, the curing process can include active temperature reduction, for example, active cooling, particularly by cooling elements and / or forced convection. The curing process of the conductor element is preferably carried out in the recess of the forming device. In particular, the negative temperature coefficient of the insulating sheath causes the flexible fibers inside the insulating sheath to tighten and can achieve filling of the entire cross-sectional volume of the conductor element.Thus, the shape of the conductor element is fully constructed, resulting in a compact conductor element with a high fill density. The conductor element can then be removed from the recess of the forming device without stress. Attached Figure Description
[0020] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Wherein:
[0021] Figure 1 A schematic view of a motor according to an embodiment of the present invention is shown.
[0022] Figure 2 A schematic view of the stator of an electric motor according to an embodiment of the present invention is shown.
[0023] Figure 3 A schematic partial view of the stator of an electric motor according to an embodiment of the present invention is shown.
[0024] Figure 4 A schematic view showing a cross-sectional view of the electrical conductor element through the plug-in winding of the stator of an electric motor according to an embodiment of the present invention.
[0025] Figure 4A A schematic view of the end region of the electrical conductor element of the stator plug winding of an electric motor according to an embodiment of the present invention is shown.
[0026] Figure 5 A schematic view showing another electrical conductor element of the stator plug-in winding of an electric motor according to an embodiment of the present invention, and
[0027] Figure 6 A schematic view of a forming apparatus for manufacturing a method of producing an electrical conductor element of a stator plug-in winding of an electric motor according to an embodiment of the present invention is shown. Detailed Implementation
[0028] Figure 1 An electric motor 1 according to an embodiment of the present invention is schematically shown. The electric motor 1 has a rotor 3 and a stator 2. The stator 2 is arranged on a housing 2a, wherein a rotor shaft 3a is rotatably supported on the housing 2a, and the rotor 3 is mounted on the rotor shaft. Thus, the rotor 3 can rotate about a central axis 100, wherein the central axis 100 is also the central axis of the stator 2. Particularly advantageously, the electric motor 1 is a drive system for a vehicle, such as a car or bicycle.
[0029] Figure 2 The stator 2 of an electric motor 1 according to an embodiment of the present invention is schematically shown. The stator 2 has a stator base 6 on which a plug-in winding 4 is disposed. The plug-in winding 4 consists of a plurality of individual rigidly insulated electrical conductor elements 5. This is in Figure 3As shown in the figure. Therefore, a plurality of I-shaped conductor elements 5 and / or U-shaped conductor elements 5 are provided, wherein these conductor elements 5 are inserted into the stator slots 7 of the stator base 6. The conductor ends 17 of the conductor elements 5 protrude from the stator slots 7, wherein the conductor ends 17 of the conductor elements 5 are matingly connected to the conductor ends 17 of other conductor elements 5 to form plug-in windings 4, particularly to realize three separate winding strips on the stator base 6. The stator base 6 is advantageously composed of a plurality of single-laminated stacks, wherein, Figure 3 For simplicity and to provide a better overview, only one stator lamination is shown among these stator laminations.
[0030] The plug-in winding 4, constructed in this way, allows strong current to flow through the conductor elements 5. Each conductor element 5 has a larger cross-section compared to conventional conductors; in particular, rectangular cross-sections are present. As a result, the current-carrying capacity of each conductor element 5 is improved, thus enabling the motor 1 to have high output power.
[0031] Figure 4 The diagram shows a cross-section through one of the insulated electrical conductor elements 5, which are used to manufacture the plug-in winding 4. Electrical conductor element 5... Figure 2 The embodiment shown is I-shaped. Figure 4A The end region of conductor element 5 is shown.
[0032] The insulated conductor element 5 comprises numerous flexible, conductive fibers 8, particularly conductor strips composed of flexible fibers 8 made of carbon nanotubes (CNTs). The flexible fibers 8 are arranged within a sleeve-shaped or hose-shaped and substantially rigid electrically insulating sheath 9. The insulating sheath 9 is preferably made of a synthetic material, particularly polyetheretherketone (PEEK).
[0033] At the conductor end 17 of the conductor element 5, the fiber end 18 of the fiber 8 extends from the insulating sheath 9 and is therefore not electrically insulated. These fiber ends 18 are used in particular for the electrical connection of the two conductor elements 5 in order to manufacture the plug-in winding 4 as described above.
[0034] The flexible fibers 8 preferably have fabric properties. Thus, the flexible fibers 8 can preferably be arranged in the insulating sheath 9 with a high fill density. The insulating sheath 9 thus determines the shape of the conductor element 5, because the rigid insulating sheath 9 imparts a rigid shape to the conductor element 5. Furthermore, a high current-carrying capacity is achieved through the numerous flexible fibers 8, while the use of carbon nanotubes results in a low density and therefore low weight for the conductor element 5. This allows for the provision of the motor 1 with a high power density.
[0035] Figure 5Another embodiment of an insulated electrical conductor element 5 with a plurality of flexible fibers 8 is shown. (Compared to...) Figure 4 The embodiments shown are different, according to Figure 5 The insulated electrical conductor element 5 is U-shaped.
[0036] The U-shaped insulated electrical conductor element 5 includes two legs 10 connected by a transverse region 11. Besides its shape, the conductor element 5 also features… Figure 4 The structure of the embodiment shown is similar to that of conductor element 5. Figure 5 The embodiments shown are no different. Therefore, in Figure 5 The diagram also shows a sleeve-shaped or hose-shaped insulating sheath 9, within which multiple flexible fibers 8 are arranged. These flexible fibers 8 extend from one leg 10 through a transverse region 11 to another leg 10 and emerge from the insulating sheath 9 at the conductor end 17 on the leg 10 as fiber ends 18. The electrical conductor element 5 is based on... Figure 5 The advantages of the embodiments shown in the figure are similar to those of the conductor element 5. Figure 4 The advantages of the embodiments shown are the same.
[0037] In both embodiments, the conductor end 17 of the conductor element 5 can be electrically contacted to electrically connect the corresponding conductor element 5 to other components. The conductor elements 5 can in particular contact with each other to form a plug-in winding 4. Thus, the conductor elements 5 can be used, in particular, as a conventional part of a plug-in winding.
[0038] Figure 6 A forming apparatus 12 is shown, which is used to manufacture the described insulated electrical conductor element 5 according to the method according to the invention. The exemplary forming apparatus 12 is particularly used for manufacturing insulated electrical conductor elements 5 according to the invention. Figure 5 The insulated electrical conductor element 5 is shown in the figure.
[0039] The forming device 12 has a base 13 and a recess 14 formed in the base 13. The recess 14 is U-shaped and, in particular, has a square or rectangular cross-sectional shape. Furthermore, other orientations of the recess 14 are conceivable, especially for manufacturing in… Figure 4 The diagram shows the I-shaped orientation of the insulated electrical conductor element 5.
[0040] The forming apparatus 12 includes a plurality of heating elements 15 which are fastened to the base 13 and are distributed around the recess 14. The heating elements 15 preferably have an elongated shape that runs along the recess 14. However, it is also conceivable that a plurality of point-like heating elements 15 are arranged along the recess 14.
[0041] The heating element 15 is preferably designed as a thermocouple. However, alternatively, it may also be constructed as, for example, a heating wire. The heating element 15 is preferably screwed into the base 13. However, a plug-in connection between the heating element 15 and the base 13 is also conceivable.
[0042] To manufacture the insulated electrical conductor element 5, a plurality of conductive, flexible fibers 8 are first guided through an insulating sheath 9. The insulating sheath 9 is sleeve-shaped or hose-shaped, having an angular or circular cross-sectional shape, and at this point, the insulating sheath does not necessarily have the final shape of the conductor element 5. Next, the insulating sheath 9, together with the flexible fibers 8 arranged therein, is arranged into a recess 14 constructed in the base 13 of the forming device 12.
[0043] After the insulating sheath 9 and the flexible fibers 8 are arranged in the recess 14, the insulating sheath 9 is heated by means of the heating element 15.
[0044] The insulating sheath 9 is preferably a thermoplastic synthetic material, especially polyetheretherketone (PEEK). Here, the insulating sheath 9 is heated to a thermoplastic range during the manufacture of the conductor element 5. The thermoplastic range is the temperature range in which the heated insulating sheath 9 retains plastic deformation, that is, it no longer has its original shape.
[0045] Next, the heat transfer via the heating element 15 is interrupted, allowing the insulating sheath 9 to preferably harden. Hardening can be passive, i.e., the cooling of the insulating sheath 9 is achieved solely by interrupting the heat transfer, without any additional measures. However, hardening can also be designed to be active, for example, using additional cooling elements and / or devices that induce forced convection. In both cases of hardening, the insulating sheath 9 is preferably held within the recess 14 so that the complete construction of the conductor element 5 can be achieved. This results in a high fill density for the conductor element 5.
[0046] Next, the conductor element 5, which essentially retains the shape of the recess 14, can be integrally removed from the recess 14. The conductor element 5 now has a fixed shape achieved by the method described.
[0047] The insulating sleeve 9 is preferably a shrink tubing and / or made of a material with a negative coefficient of thermal expansion. Thus, the insulating sleeve 9 is preferably heat-shrinkable onto a plurality of flexible fibers 8 and is preferably configured to apply tension to the flexible fibers 8, especially the conductor strips, located within the insulating sleeve 9 when heated by the heating element 15. This tightly encapsulates the fibers 8 and thus achieves a high packing density of the conductor elements 5. Together with the low density of the carbon nanotubes, the plug-in winding 4 composed of the conductor elements 5 can thus achieve high current carrying capacity while maintaining low weight. The motor 1 thus has a high power density.
Claims
1. An electric motor (1) having a rotor (3) and a stator (2), wherein, The stator (2) and / or the rotor (3) have an electrically plug-in winding (4) comprising a plurality of rigid, insulated electrical conductor elements (5), wherein the electrical conductor elements (5) are arranged in slots of the stator (2) or the rotor (3) and protrude from the slots with conductor ends (17), wherein the conductor ends (17) of the electrical conductor elements (5) are respectively connected to the conductor ends (17) of other conductor elements among the electrical conductor elements (5) to form the electrically plug-in winding (4), wherein the electrical conductor elements (5) have an electrically insulating sheath (9), characterized in that each electrical conductor element (5) comprises a plurality of flexible fibers (8), and the insulating sheath (9) surrounds the plurality of fibers (8) in a flexible manner and is configured such that the insulating sheath imparts a rigid shape to the electrical conductor element (5), such that the rigid shape of the electrical conductor element (5) is not given by the flexible fibers (8) but by the insulating sheath (9).
2. The motor (1) according to claim 1, characterized in that, The insulating sheath (9) is heat-shrinked onto a number of flexible fibers (8).
3. The motor (1) according to claim 1 or 2, characterized in that, The insulating sheath (9) tensions a number of flexible fibers (8) in the insulating sheath (9).
4. The motor (1) according to claim 1 or 2, characterized in that, The insulating sheath (9) is made of thermoplastic synthetic material.
5. The motor (1) according to claim 1 or 2, characterized in that, The insulating sheath (9) is made of an insulating material with a negative coefficient of thermal expansion.
6. The motor (1) according to claim 1 or 2, characterized in that, Each electrical conductor element (5) is constructed in a U-shape or I-shape and has a quadrilateral cross-section.
7. The motor (1) according to claim 1 or 2, characterized in that, The flexible fiber (8) of each electrical conductor element (5) extends from the corresponding insulating sheath (9) at the two conductor ends (17) of the corresponding electrical conductor element (5) with flexible fiber ends (18) for electrically connecting the corresponding electrical conductor element (5) to other conductor elements in the electrical conductor element (5).
8. The motor (1) according to claim 1, characterized in that, Each electrical conductor element (5) comprises a number of flexible fibers in a conductor strip consisting of flexible fibers (8) made from carbon nanotubes or graphene.
9. The motor (1) according to claim 8, characterized in that, The insulating sheath (9) tensions the conductor strip.
10. The motor (1) according to claim 4, characterized in that, The insulating sheath (9) is made of polyetheretherketone.
11. The motor (1) according to claim 6, characterized in that, Each electrical conductor element (5) has a rectangular cross-section.
12. The motor (1) according to claim 8, characterized in that, The conductor strip of each electrical conductor element (5) extends from the corresponding insulating sheath (9) at the two conductor ends (17) of the corresponding electrical conductor element (5) with flexible fiber ends (18) for electrically connecting the corresponding electrical conductor element (5) to other conductor elements in the electrical conductor element (5).
13. A method for manufacturing a rigid, insulated electrical conductor element (5), said electrical conductor element being used in the electrically connected windings (4) of the rotor (3) and / or stator (2) of an electric motor (1) according to any one of claims 1 to 12, said method comprising the following steps: - In the case of forming an electrical conductor element (5), a strip of flexible fiber (8) made of carbon nanotubes or graphene is surrounded by a tubular insulating sheath (9). - The electrical conductor element (5) is arranged in the forming recess (14) of the forming device (12). -The conductor element (5) is heated to a temperature that causes the insulating sheath (9) to thermally shrink by means of at least one heating element (15) in the recess of the forming device (12), and - Cool the electrical conductor element (5).
14. The method according to claim 13, characterized in that, The electrical conductor element is used in the electrical plug-in winding (4) of the rotor (3) and / or stator (2) of the electric motor of the electric drive vehicle.
15. The method according to claim 13, characterized in that, The electrical conductor element (5) is heated to a temperature that causes the insulating sheath (9) to shrink by means of at least one heating element (15) in the recess of the forming device (12).