Stator for an electronically commutated DC motor

Abstract

Stator (1) for an electronically commutated DC motor, comprising a stator lamination stack (2) with a plurality of stacked stator laminations (3), wherein a symmetrically designed stator ring (4) with radially arranged stator teeth (5) for an electrical winding (6) is formed, wherein the stator lamination stack (2) has a hub (7) through which an axle (8) is received, wherein the stator lamination stack (2) has at least one torque support (9), and wherein the at least one torque support (9) extends radially from the hub (7) to a region of the stator teeth (5), wherein connecting wires (15) of the winding (6) are guided through a recess (16) in the axis (8).

Description

[0001] The invention relates to a stator for an electronically commutated DC motor.

[0002] It is known to integrate electric motors into or onto the wheels or tires of vehicles to drive them directly. This has the advantage of saving space and eliminates the need for a complex drivetrain with shafts and gearboxes. The efficiency of the drive system also increases due to the direct connection to the vehicle wheel. Electric motors of this type can be used, particularly in the form of wheel hub drives, for electrically powered vehicles such as electric scooters or e-bikes. These combine high mobility, especially in urban traffic, with zero CO2 emissions during operation.

[0003] Typically, these types of electric motors have a stator mounted inside a wheel rim on a shaft that connects to the vehicle or the vehicle wheel, usually the rear wheel. The stator may be surrounded by a rotor that rotates around it and is also mounted within the wheel rim. The torque generated by the rotational movement, through the interaction between the two magnetic fields, is used to drive the vehicle wheel. No additional gearbox is required. Commutation between the stator and rotor is electronic, with the (control) electronics usually housed within the vehicle.

[0004] In known stators for an electronically commutated DC motor, particularly an external rotor motor, the stator comprises a stator core with a plurality of stator teeth. The stator core is mounted on a stator support, which accommodates a shaft or axle. However, this leads to tolerance problems, as the stator core must be adapted to the stator support in terms of its inner circumference and thickness.

[0005] The object of the invention is to provide a stator for an electronically commutated DC motor which is easy to manufacture, saves additional processes, ensures good stability and good heat dissipation, saves components and avoids tolerance problems.

[0006] This problem is solved by the stator according to the features of claim 1.

[0007] According to the invention, the stator for an electronically commutated DC motor comprises a stator lamination stack with a plurality of stacked stator laminations, wherein a symmetrically designed stator ring with radially arranged stator teeth for an electrical winding is formed, wherein the stator lamination stack has a hub through which an axle is received, wherein the stator lamination stack has at least one torque support, and wherein the at least one torque support extends radially from the hub to a region of the stator teeth. Advantageously, connecting wires of the winding are guided through a recess in the axle. The connecting wires of the individual phases are bundled in cable insulation and guided through a recess in the axle. For good stability, the stator lamination stack should preferably have at least two, and advantageously three, torque supports.The at least one torque support is preferably rigid, i.e., torsionally stiff. The stator lamination stack consists of a plurality of stator laminations stacked precisely on top of each other. The one-piece formation of the stator ring, the at least one torque support, and the hub within a single stator lamination / stator lamination stack advantageously eliminates the need for an additional stator support. This has the advantage that the thickness and inner diameter of the stator lamination stack do not need to be adapted to the dimensions of the stator support. This eliminates tolerance problems regarding the thickness and inner diameter of the stator lamination stack in relation to the stator support.The stator according to the invention is designed for an electronically commutated external rotor motor, in particular for wheel hub drives in electrically powered vehicles, and is used in electric scooters, electric bicycles, or other electrically powered means of transport known to those skilled in the art. However, the stator according to the invention can also be used for other applications in which the stator consists of a laminated core.

[0008] In a further development, the at least one torque arm, the hub and the stator ring are formed by a punch during a punching process, preferably simultaneously. The stator ring, at least one torque arm and the hub are preferably punched out of a sheet metal strip and punched together. As a result, the stator ring, the at least one torque arm and the hub are formed integrally in a stator sheet. This has the advantage that the stator ring, the at least one torque arm and the hub do not have to be stamped as individual parts and then joined together to form a stator sheet. This means fewer process steps are necessary. This also results in fewer parts, which reduces the potential for errors and reduces costs. Alternatively, the stator ring, the at least one torque arm and the hub can be punched out and punched together partially one after the other.This is particularly recommended for larger components. For smaller components, it is technically simpler to stamp and stack the stator rim, at least one torque support, and the hub, preferably simultaneously. During stamp stacking, the individual stator laminations are twisted relative to each other and stacked on top of each other.

[0009] One advantage is that the at least one torque arm forms a connection between the hub and the stator ring. The hub is connected to the stator ring via the at least one torque arm. The at least one, preferably at least two, advantageously three, torque arms are formed from the hub, which is arranged in the center of the stator laminated core, to the stator ring. The hub has a hexagonal shape; however, it can also be formed in a different shape. As a result, the at least one torque arm, the hub and the stator ring do not have to be connected to one another as individual parts. However, it is also conceivable to connect the stator ring, the at least one torque arm and the hub as individual parts. Alternatively, at least one torque arm can be formed from the hub to the stator ring and a further torque arm can be formed from the hub towards the stator ring without a connection to the stator ring.It would also be conceivable to design at least one torque support with a connection of the stator ring towards the hub without a connection to the hub.

[0010] According to the invention, the hub has an axle mount with at least one keyway. At least one, preferably several, keyways are formed in the axle mount of the hub. These keyways do not have a spring-loaded action. Depending on the torque requirement, the at least one keyway creates a force-locking and / or form-locking connection between the axle and the axle mount. The axle can be positively mounted in the axle mount by pressing it in or applying a high torque. For additional form-locking of the axle in the axle mount, a key is inserted into the at least one keyway.

[0011] Advantageously, a bushing is partially integrated into the hub and / or provided on the axle in the area of ​​the axle mounting. The bushing contributes to improved axle support within the hub or axle mounting. Alternatively, the bushing can be omitted from the hub or axle mounting. At least one additional bearing is mounted on the axle.

[0012] In this further development, the torque supports are spaced apart from each other. The torque supports are arranged radially around the hub in the stator lamination / stator core. The spacing between the torque supports creates gaps within the stator lamination. These gaps in the stator lamination save material and therefore weight. The radial spacing of the torque supports enables high torque and balances the stator lamination.

[0013] An advantage is that a number of holes are distributed across the at least one torque support and the hub. This means that the torque support and the hub are not solid bodies, saving material and therefore weight. Most of the holes are required for connecting the individual stator laminations to form a stator lamination stack.

[0014] Advantageously, the stator laminations are connected to one another in a force-fitting and / or form-fitting manner, particularly by riveting, in the region of the bores. The stator laminations are connected to one another in a force-fitting and / or form-fitting manner by riveting across the plurality of bores in the at least one torque arm and the hub. The rivets are commercially available rivets or special hollow rivets that are pressed in or fastened by other methods known to those skilled in the art. The connection can also be made using bolts, pins, or other fasteners known to those skilled in the art. Riveting provides a cost-effective process.

[0015] According to the invention, an insulating ring is arranged on each of the axial end faces of the stator rim. The electrical winding is guided and contacted via at least one insulating ring and the stator rim. The electrical winding can be produced by a single continuous winding wire or several winding wires, depending on the specific connection configuration. The stator can be connected by a star-parallel winding, a star-series winding, a delta-series winding, a delta-parallel winding, a delta-half-parallel winding, a delta-double-parallel winding, or a delta-quadruple-parallel winding.

[0016] Advantageously, the winding's connecting wires are guided through a recess in the socket. The connecting wires of the individual phases are bundled within cable insulation and guided through a recess in the shaft and / or the socket.

[0017] In this advanced design, at least one layer of electrical insulation is arranged between the individual stator teeth in the stator ring. Due to the limited space between the stator teeth, paper insulation is more suitable than plastic insulation. Alternatively, plastic or another suitable insulating material can be used. The electrical insulation keeps the electrical winding away from the contact plates.

[0018] The invention is not limited to the embodiments mentioned. Rather, it encompasses all embodiments that can be implemented within the scope of expert practice and with minor modifications by a person skilled in the art.

[0019] Embodiments of the invention are explained in more detail below with reference to the drawings. They show: Fig. 1. A spatial representation of the stator lamination stack Fig. 2 a top view of the stator according to the invention Fig. 3 an exploded view of the stator according to Fig. 2

[0020] Fig. Figure 1 shows a spatial representation of the stator lamination stack (2) with a plurality of stacked stator laminations (3), wherein a symmetrically designed stator ring (4) with radially arranged stator teeth (5) for an electrical winding (6) (not shown here) is formed, wherein the stator lamination stack (2) has a hub (7) through which an axle (8) (not shown here) is received, wherein the stator lamination stack (2) has at least one torque support (9), and wherein the at least one torque support (9) extends radially from the hub (7) to a region of the stator teeth (5). The at least one torque support (9) forms a connection between the hub (7) and the stator ring (4). The hub (7) has an axle receptacle (10) with at least one keyway (11). The torque supports (9) are spaced apart from each other and form gaps.A plurality of bores (13) are arranged distributed on at least one torque support (9) and the hub (7). The stator laminations (3) are connected to each other in the area of ​​the bores (13) by means of force-fit and / or form-fit, in particular by rivets.

[0021] Fig. 2 shows a plan view of the stator (1) according to the invention for an electronically commutated DC motor, comprising a stator lamination stack (2) with a plurality of stacked stator laminations (3), wherein a symmetrically designed stator ring (4) with radially arranged stator teeth (5) is formed for an electrical winding (6), wherein the stator lamination stack (2) has a hub (7) through which an axle (8) is received, wherein the stator lamination stack (2) has at least one torque support (9), and wherein the at least one torque support (9) extends radially from the hub (7) to a region of the stator teeth (5). The at least one torque support (9) forms a connection between the hub (7) and the stator ring (4). The stator (1) has an electrical winding (6), which is designed here as a delta quadruple parallel winding. However, another type of winding connection is also possible.The connecting wires (15) of the winding (6) are bundled and guided through a recess (16) in the axis (8) and / or the socket (12).

[0022] Fig. Figure 3 shows an exploded view of the stator (1) according to Fig.2. The stator ring (4) with the radially arranged stator teeth (5) has an electrical winding (6). An insulating ring (14) is arranged on each of the axial end faces of the stator ring (4). At least one electrical insulation (17) is arranged in the stator ring (4) between the individual stator teeth (5). This electrical insulation (17) can be made of paper. However, other insulating materials are also conceivable. The electrical insulation (17) is inserted between the individual stator teeth (5) before the stator teeth (5) are wound. Advantageously, the stator laminations are connected to each other in the area of ​​the bores by means of a force-fit and / or form-fit connection, in particular by rivets. The stator laminations are connected by means of a force-fit and / or form-fit connection via the majority of bores in the at least one torque support and the hub by means of rivets.The rivets are either standard commercial rivets or special hollow rivets, which are pressed in or fastened by other methods known to those skilled in the art. The connection can also be made using bolts, pins, or other fasteners known to those skilled in the art. List of reference symbols 1 stator 2 Stator lamination package 3 Stator laminations 4 Stator ring 5 stator tooth 6 windings 7 hub 8-axis 9 Torque support 10 axle mounting 11 Keyway 12 sockets 13 boreholes 14 Insulating ring 15 connecting wires 16 Exclusion 17 Insulation

Claims

[1] Stator (1) for an electronically commutated DC motor, comprising a stator laminated core (2) with a plurality of stacked stator laminations (3), wherein a symmetrically formed stator ring (4) with radially arranged stator teeth (5) is formed for an electrical winding (6), wherein the stator core (2) has a hub (7) through which an axle (8) is received, wherein the stator laminated core (2) has at least one torque support (9), and wherein the at least one torque support (9) extends radially from the hub (7) to a region of the stator teeth (5), wherein connecting wires (15) of the winding (6) are guided through a recess (16) in the axis (8). [2] Stator according to claim 1, wherein the at least one torque support (9), the hub (7) and the stator ring (4) are formed by a punch during a punching package, preferably simultaneously. [3] Stator according to claim 1 or 2, wherein the at least one torque support (9) forms a connection of the hub (7) with the stator ring (4). [4] Stator according to claim 1, 2 or 3, wherein the hub (7) has an axle receptacle (10) with at least one keyway (11). [5] Stator according to one of the preceding claims, wherein a bushing (12) is partially received by the hub (7) and / or is provided in the region of the axle receptacle (10) on the axle (8). [6] Stator according to one of the preceding claims, wherein the torque supports (9) are arranged at a distance from one another. [7] Stator according to one of the preceding claims, wherein a plurality of bores (13) are arranged distributed on the at least one torque support (9) and on the hub (7). [8] Stator according to claim 7, wherein the stator laminations (3) are connected to one another in a force-fitting and / or form-fitting manner, in particular by riveting, in the region of the bores (13). [9] Stator according to one of the preceding claims, wherein an insulating ring (14) is arranged on each of the axial end faces of the stator ring (4). [10] Stator according to one of the preceding claims, wherein the connecting wires (15) of the winding (6) are guided through a recess (16) in the bushing (12). [11] Stator according to one of the preceding claims, wherein at least one electrical insulation (17) is arranged in the stator ring (4) between the individual stator teeth (5).

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