High-speed engine for a motor vehicle

Abstract

The invention relates to a high-speed machine for a motor vehicle, comprising a stator and a rotor rotatably mounted relative to the stator along an axis, wherein the stator comprises a stator yoke and stator teeth, wherein the stator teeth are connected to the stator yoke by force and / or form locking, wherein The rotor comprises axially stacked laminations forming a laminated core, the laminated core comprising at least two receiving spaces in the radial direction to the axis, each receiving space containing a permanent magnet, the permanent magnet being force-fitted into the respective receiving spaces, the laminated core with the permanent magnets having a circular outer contour in the radial direction to the axis, and the rotor being enclosed by a retaining band to fix the permanent magnets in the laminated core.

Description

[0001] The present invention relates to a high-speed machine for a motor vehicle.

[0002] In today's electrified vehicles, high-speed motors play a crucial role due to their numerous advantages, which significantly contribute to improving drive technology. These motors are characterized by a high power density, enabling them to deliver more power per kilogram of weight, which can significantly increase vehicle efficiency and performance. The higher speeds also allow for more compact and lighter motor designs, reducing the vehicle's overall weight and thus improving its range. Furthermore, high-speed motors make it possible to eliminate the need for extensive transmission systems in certain design concepts, further reducing vehicle weight and improving mechanical efficiency.

[0003] The efficient operation of these machines further reduces the need for complex thermal management systems, which in turn lowers vehicle weight. Their compact design offers greater flexibility for integration into various vehicle platforms, enabling innovative and diverse vehicle designs. Overall, high-speed machines contribute significantly to increasing the efficiency, power-to-weight ratio, and overall performance of electric drive systems, resulting in improved performance and a longer range for modern electric vehicles.

[0004] The present invention addresses the challenges of the prior art of providing an improved electric machine with respect to improved torque and power density.

[0005] According to the invention, a high-speed engine for a motor vehicle according to claim 1 and a motor vehicle with a high-speed engine according to claim 10 are provided. Advantageous embodiments can be found in the dependent claims and the description.

[0006] The invention relates to a high-speed machine for a motor vehicle, comprising a stator and a rotor rotatably mounted relative to the stator along an axis, wherein the stator comprises a stator yoke and a plurality of stator teeth, wherein the stator teeth are connected to the stator yoke by force and / or form locking, wherein The rotor comprises axially stacked laminations forming a laminated core, the laminated core comprising at least two receiving spaces in the radial direction to the axis, each receiving space containing a permanent magnet, the permanent magnet being force-fitted in the receiving space, the laminated core with the permanent magnets having a circular outer contour in the radial direction to the axis, and the rotor being enclosed by a retaining band to fix the permanent magnets in the laminated core.

[0007] In an advantageous further development, the stator can be made of or comprise electrical steel.

[0008] Electrical steel, also known as dynamo steel, is a specially developed ferromagnetic material used in electrical engineering for the manufacture of cores in electric machines. Electrical steel can be made of or comprise silicon-iron alloys. These alloys can exhibit specific magnetic properties to minimize energy losses due to eddy currents and hysteresis. Key properties of electrical steel include high magnetic permeability, which allows the material to be easily magnetized, and low hysteresis losses. This means that little energy is converted into heat during magnetization processes.Furthermore, electrical steel can exhibit low eddy current losses, which can be achieved through a special alloy and / or thin sheet thickness and / or possible electrical insulation between the individual sheets of the laminated core. Electrical steel can be produced in various shapes and grades to meet the specific requirements of each application. It can be supplied as cold-rolled, non-grain-oriented (NGO) and grain-oriented (GO) electrical steel.

[0009] In an advantageous further development, windings for generating a rotating magnetic field can be inserted between the stator teeth. These windings can be formed from continuous conductors with either a rectangular or a circular cross-sectional profile. These can also be referred to as continuous wave windings. In this configuration, the continuous wave winding is inserted radially from the outside between the multitude of stator teeth and axially connected to the stator yoke by force-fit and / or positive locking.

[0010] In advanced training, the conductors of the continuous wave winding include cavities through which a fluid or gas can flow, thus enabling high cooling capacity due to the high heat transfer between the conductors and the fluid or gas. The conductors can be made of, or comprise, an electrically conductive material such as copper or aluminum.

[0011] In a further advantageous design, the stator teeth can be made of or comprise cobalt-iron. This increases the magnetic permeability and allows for a higher magnetic flux, thereby generating more electromagnetic torque within the same machine footprint.

[0012] In a further development, the stator yoke is made of cobalt-iron or is made entirely of cobalt-iron, which can further increase the electromagnetic torque.

[0013] Permanent magnets, force-fitted into the receiving spaces of the lamination stack, can offer several advantages. By reducing magnetic leakage flux, the performance (especially the electromagnetic torque) and efficiency of the high-speed machine can be improved.

[0014] In connection with the insertion of the permanent magnets into the receiving spaces of the rotor or the rotor lamination stack, the term "force-fit" refers to the way in which the magnets are fastened in the rotor or the lamination stack, which is ensured by a retaining band with an undersized dimension.

[0015] The shape of the magnets and the receiving spaces is designed so that they interlock and form a fit; the retaining band prevents movement or slippage of the magnets.

[0016] An additional significant advantage of this arrangement is the increased mechanical stability of the permanent magnets, as they are securely integrated into the rotor or the lamination stack, preventing them from slipping or falling out at high speeds. This can enhance the mechanical integrity of the entire assembly.

[0017] Furthermore, the precise placement of the magnets allows the magnetic field to be optimally generated and utilized, which can increase the efficiency of the high-speed machine.

[0018] The force-fit insert reduces the magnetic leakage flux within the rotor lamination stack, which can lead to reduced magnetic losses and thus to higher efficiency of the high-speed machine.

[0019] Another advantage can be the reduction of vibrations and associated noise, since the force-fit fixing of the magnets reduces imbalance and can ensure quieter operation with a reduced rolling bearing load of the high-speed machine.

[0020] Another practical advantage can be the reduced assembly effort, as the force-fit insertion of the permanent magnets into the sheet metal stack simplifies and speeds up the assembly process.

[0021] The axis of the high-speed machine is the imaginary line around which all rotating parts of the high-speed machine, such as the rotor, in particular the lamination stack, the permanent magnets and the retaining belt, rotate.

[0022] Radial to the axis refers to a direction that extends outwards or inwards from the axis. In relation to the axis, radial means that the movement or arrangement is perpendicular to the axis, i.e., along a line radiating from the center of the axis.

[0023] Axial to the axis refers to a direction along the axis. In contrast to "radial," which points away from or towards the axis, "axial" describes movements, forces, or arrangements that run parallel to the axis.

[0024] In a further training course, the retaining strap is trained as a carbon fiber bandage.

[0025] In a further training, the fiber direction of the carbon fiber bandage extends radially around the rotor.

[0026] A significant advantage of using carbon fiber wrapping in high-speed machines to secure the permanent magnets within the lamination stack lies in the outstanding mechanical properties of carbon fibers. These materials are characterized by their exceptionally high tensile strength and stiffness, enabling them to withstand high mechanical loads. This is particularly important in high-speed machines, where high centrifugal forces are at play, which must securely hold the permanent magnets in place.

[0027] In a further development, the rotor comprises 4, 6, or 8 mounting spaces, each for holding a permanent magnet. The number of mounting spaces determines the number of poles or the number of magnet pairs of the electric machine.

[0028] The number of pole pairs in a high-speed machine refers to the number of magnetic poles, more precisely, north and south pole pairs, present on the machine's rotor. This parameter is crucial for determining the relationship between the rotor speed and the electrical frequency of the generated or applied voltage. In other words, a pole pair consists of a north pole and a south pole. The number of pole pairs is the total number of poles divided by two. For example, a machine with four magnetic poles (two north poles and two south poles) has a pole pair number of two. The pole pair number significantly influences the machine's operating characteristics and is directly related to the synchronous speed of the high-speed machine. For instance, a pole pair number of two, or a pole count of four, corresponds to four mounting spaces in the laminated core.

[0029] In a further advantageous design, the high-speed machine is configured as a permanent magnet synchronous machine. The permanent magnet synchronous machine (PMSM) is a special type of synchronous machine in which the magnetic field in the rotor can be generated by permanent magnets. This design can offer several advantages, such as higher efficiency, lower losses, and a more compact construction.

[0030] In further training, the position of the receiving space on the rotor, in particular on the laminated core, can be determined using the equation θn=360°2⋅pn calculated where p corresponds to the number of pole pairs of the high-speed machine and thus 2*p is the number of poles, n is the consecutive number of the recording space and θ_n is the angular position in degrees of the respective recording space depending on n.

[0031] In a further training course, the respective permanent magnet is designed as a circular sector or as a triangle.

[0032] A circular sector is a portion of a circle bounded by a first radius, a second radius, and the arc between them. The shape of a circular sector is defined by the center of the circle and two points on its circumference. The angle formed between the two radii of the sector at the center of the circle is called the central angle and is measured in degrees (°) or radians (rad). The two line segments extending from the center of the circle to two different points on the circumference are the radii that define the circular sector. The portion of the circumference between these two points on the circle, connecting the two radii, is called the arc of the circular sector. In a more advantageous design, the first and second radii can be identical.

[0033] In an advantageous further development, the receiving space in the sheet metal stack has an opening angle which corresponds to the central angle of the associated permanent magnet which is inserted into the respective receiving space.

[0034] In a further training course, the radius of the circular arc of the circular sector corresponds to the radius of the rotor. The radius of the circular arc is not related to the circular sector itself, but rather to the axis of the high-speed machine. Therefore, the radius of the circular sector, i.e., of the respective permanent magnet, does not necessarily correspond to the radius of the rotor.

[0035] In other words, each permanent magnet fits into the laminated core, in particular into the respective receiving space of the rotor's laminated core, in such a way that the respective permanent magnets complete an outer contour of the laminated core and thus the rotor as a whole to form a circular outer contour.

[0036] In a further development, the respective circular arc of the circular sector of each permanent magnet and the rotor's laminated core form a circular outer contour relative to the axis. The permanent magnets embedded in the rotor can thus follow the rotor's outer radius with their radially outward-facing side. The outward-facing side is the side that is not inserted into the receiving space or in contact with the rotor's laminated core.

[0037] A "circular outer contour" describes the shape of an object whose outer boundary follows a circular pattern. This means that the object's outer edge is equidistant from a central point in all directions, so the object's shape corresponds to a circle. Manufacturing tolerances are to be disregarded when considering a circular outer contour.

[0038] In a further development, the receiving space is triangular, and each permanent magnet has a sector-like contour, comprising a first radius and a second radius, the two radii converging to a point which is inserted into the respective receiving space. In an advantageous further development, the point of each permanent magnet can point towards the center of the rotor, particularly towards the axis. The first radius and the second radius enclose a central angle α.

[0039] The invention also relates to a high-speed machine according to at least one of the preceding further developments.

[0040] The invention is described below by way of example only, with reference to the drawings. The drawings show: Fig. Figure 1 shows a high-speed machine for a motor vehicle according to an embodiment of the invention; and Fig. 2 a permanent magnet with a circular sector-like contour according to an embodiment of the invention.

[0041] Fig. Figure 1 shows a high-speed motor 100 for a motor vehicle, comprising a stator 110 and a rotor 120 rotatably mounted relative to the stator 110 along an axis 200. The stator 110 comprises a stator yoke 111 and a plurality of stator teeth 112, the stator teeth 112 being connected to the stator yoke 111 by friction and / or form-fit. The rotor 120 comprises axially stacked electrical iron laminations forming a laminated core 121, the laminated core 121 comprising at least two receiving spaces 122 radially to the axis 200, each receiving space containing a permanent magnet 125. The permanent magnet 125 is frictionally engaged in the respective receiving spaces 122. The laminated core 121 with the permanent magnets has a circular outer contour in the radial direction to the axis 200, wherein the rotor 120 is enclosed by a retaining band 130 for fixing the permanent magnets 125 in the laminated core.

[0042] Each permanent magnet 125 has a sector-like contour. The permanent magnet comprises a first radius 126 and a second radius 127, with the two radii converging at a point. The first radius 126 and the second radius 127 enclose a central angle α at the point. The sector is a portion of a circular area bounded by the first radius 126 and the second radius 127 and the arc 128 between them. The first radius 126 and the second radius 127 are equal in size.

[0043] Fig.Figure 2 shows a permanent magnet 125 with a circular sector-like contour. The permanent magnet comprises a first radius 126 and a second radius 127, with the two radii converging at a point. The first radius 126 and the second radius 127 enclose a central angle α. The circular sector is a sub-region of a circular area bounded by the first radius 126 and the second radius 127 and the intervening circular arc 128.

[0044] The invention is not limited to the described embodiments. Within the scope of the invention, all described and / or drawn features can be combined with one another as desired, unless otherwise stated.

Claims

[1] High-speed engine (100) for a motor vehicle, comprehensive a stator (110) and a rotor (120) rotatably mounted relative to the stator (110) along an axis (200), wherein the stator (110) comprises a stator yoke (111) and a plurality of stator teeth (112), wherein the stator teeth (112) are forcefully and / or positively connected to the stator yoke (111), wherein the rotor (120) comprises axially layered laminations which form a lamination stack (121), wherein the sheet metal package (121) comprises at least two receiving spaces (122) in the radial direction to the axis (200), wherein In each receiving space (122) a permanent magnet (125) is arranged, wherein each permanent magnet (125) is force-fitted into the respective receiving spaces (122), wherein the laminated core (122) with the permanent magnets has a circular outer contour in the radial direction to the axis (200), wherein the rotor (120) is enclosed by a retaining band (130) for fixing the permanent magnets (125) in the laminated core. [2] High-speed machine (100) for a motor vehicle according to claim 1, characterized by , that the retaining strap (130) is designed as a carbon fiber bandage. [3] High-speed machine (100) for a motor vehicle according to claim 2, characterized by , that the fiber direction of the carbon fiber bandage (130) extends radially around the rotor (120). [4] High-speed machine (100) for a motor vehicle according to claim 1, characterized by, that the rotor (120) comprises 4 or 6 or 8 receiving spaces (122) for receiving one permanent magnet (125) each. [5] High-speed machine (100) for a motor vehicle according to one of the preceding claims, characterized by , that the position of the receiving chamber (122) on the rotor (120) is given by the equation θn=360°2⋅pn can be calculated where 2*p corresponds to a pole number of the high-speed machine (100), n to the running number of the recording space (122) and θ_n to the angular position in degrees of the respective recording space (121) depending on n. [6] High-speed engine for a motor vehicle according to claim 5, characterized by , that the respective permanent magnet (125) is designed as a circular sector. [7] High-speed motor machine for a motor vehicle according to claim 6, characterized by , that a radius of a circular arc (128) of the circular sector corresponds to a radius of the rotor (120). [8] High-speed engine for a motor vehicle according to claim 7, characterized by , that each circular arc (128) of the circular sector of the respective permanent magnet (125) and the laminated core (121) of the rotor (120) form a circular outer contour with respect to the axis (200). [9] High-speed machine (100) for a motor vehicle according to one of claims 6 to 8, characterized by , that the receiving space (122) is triangular in shape and each permanent magnet (125) has a sector-shaped contour, wherein the permanent magnet comprises a first radius (126) and a second radius (127), the two radii converging to a point which is inserted into the respective receiving space (122). [10] Motor vehicle with a high-speed engine (100) according to at least one of the preceding claims.

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