Stator, electric motor, cleaning device, and production method

Abstract

The invention relates to a stator (4) for an electric motor (3), wherein the stator (4) has inwardly directed stator teeth (11), and only every other stator tooth (11) is wound with a stator winding (5). The stator is characterized in that the stator (4) is completely overmolded with a plastic compound (10). The invention further relates to an electric motor comprising such a stator, to a cleaning device comprising such an electric motor or stator, and to a method for producing the aforementioned devices.

Description

[0001] Description

[0002] Stator, electric motor, cleaning device and manufacturing process

[0003] Technical area

[0004] The invention relates to a stator, an electric motor, a cleaning device and a manufacturing method.

[0005] State of the art

[0006] Stators known from the state of the art have the disadvantage that performance losses or malfunctions can be caused by contact of the stators with moisture.

[0007] In order to overcome this disadvantage, it is common practice in the state of the art to provide numerous components to protect the stator, which is why the assembly effort for electric motors equipped with such stators increases considerably.

[0008] Description of the invention, task, solution, advantages

[0009] The object of the present invention is to provide an alternative stator that is particularly characterized by its resistance to moisture. Furthermore, the object of the present invention is to provide an electric motor and a cleaning device with the same advantages. Furthermore, it is an object to provide a manufacturing method for producing the stator according to the invention, the electric motor according to the invention, and the cleaning device according to the invention.

[0010] The problem with regard to the stator is solved by a stator having the features of claim 1. One embodiment of the invention relates to a stator for an electric motor, wherein the stator has inwardly directed stator teeth, wherein only every second stator tooth is wound by a stator winding, wherein the stator is completely overmolded with a plastic compound. This creates a particularly durable and robust stator that, in particular, overcomes the disadvantages of the prior art.

[0011] It is particularly advantageous if the electric motor for which the stator is intended is an internal rotor. Furthermore, it is preferred if the electric motor is a permanent magnet synchronous motor. The stator winding is preferably a concentrated winding. Furthermore, it is preferred if the stator is a segmented stator. In this case, it is conceivable that the individual stator segments are secured to one another by the plastic compound.

[0012] Furthermore, it is preferred if, viewed in the circumferential direction of the stator, every second stator tooth is alternately wound or unwound by means of a stator winding. In other words, each wound stator tooth is preferably followed in the circumferential direction by an unwound stator tooth. It is expedient if an unwound stator tooth has a continuous taper, i.e., becomes narrower, in its direction of extension away from the stator yoke of the stator. Furthermore, it is expedient if a wound stator tooth has a widening, preferably abrupt, at its end facing away from the stator yoke of the stator, in particular the end directed radially inward.

[0013] It is also advantageous if the plastic compound is an electrically insulating material. Alternatively, it is conceivable for the plastic compound to be made of an electrically conductive material. In such a case, it is preferred if a ground connection for discharging electromagnetic voltages from the stator to a ground connection point is formed using the plastic compound. Complete overmolding means, in particular, that the stator is completely protected from liquids and moisture by the plastic compound. This contributes to its longevity and prevents malfunctions in an electric motor equipped with such a stator.

[0014] A preferred embodiment is characterized in that a convection channel is formed between the stator winding of at least one wound stator tooth and an adjacent, unwound stator tooth. The convection channel is preferably designed as an air channel for free convection. This achieves a particularly simple yet effective cooling effect.

[0015] Furthermore, it is preferred if the convection channel is limited radially to its direction of extension, in particular only, by the plastic mass.

[0016] It is also preferable if the convection channel is connected to a heat sink in a heat-conducting manner. Irrespective of this, the convection channel is preferably fluid-tight. Alternatively, it is conceivable for the convection channel to communicate fluidically with the surroundings of the stator or with the surroundings of a peripheral device to which the stator is attached.

[0017] In principle, all previously mentioned and subsequent embodiments that refer to a convection channel are also transferable to embodiments with more than one convection channel. In such a case, one, several, or all convection channels can be designed according to the embodiment.

[0018] The convection channel is preferably designed to increase the heat transfer surface from the heat source, in particular the stator winding, to the spaces between the stator teeth, here designed as fabrication channels. Another preferred embodiment is characterized in that the convection channel extends over the entire length of the stator. This achieves a particularly effective cooling effect.

[0019] A further preferred embodiment is characterized in that the stator comprises several convection channels. This allows for even better cooling of the stator. Each of the convection channels is preferably arranged between the stator winding of a wound stator tooth and an unwound stator tooth. It is particularly preferred if a convection channel is arranged between each wound stator tooth and each adjacent unwound stator tooth. This further increases the cooling performance.

[0020] A further preferred embodiment is characterized in that the plastic compound is used to overmold the integral connections between electrical conductors. This protects the integral connections not only from moisture but also from vibrations. The integral connections are preferably soldered or welded connections. The electrical conductors are preferably parts or ends of the stator winding or electrical conductors that are electrically connected to the stator winding. The integral connections are preferably electrically conductive connections.

[0021] A further preferred embodiment is characterized in that a stator or electric motor housing is formed by means of the plastic compound, which housing, in particular, has connecting openings for forming a fastening to a peripheral device. This reliably protects the stator or an electric motor of which the stator is a part, while also allowing it to be easily fastened to a peripheral device.

[0022] A further preferred embodiment is characterized in that the stator is electrically insulated from the plastic compound and / or the stator winding by means of an insulating compound. This increases the functional reliability of the stator and the electric motor, of which the stator may be a part, since relative movement between the stator winding and the stator, caused by the operation of the stator and the associated vibrations, cannot lead to a short circuit between the stator winding and the stator. Even if the insulation of the stator winding were to fail due to vibrations, the insulating compound insulating the stator prevents and prevents such a short circuit.

[0023] Furthermore, it is preferred if the convection channel is limited radially to its direction of extension only by the plastic mass and the insulated mass.

[0024] The object of the electric motor is achieved by providing an electric motor with a stator according to the invention. Such an electric motor has the same advantages as the stator according to the invention.

[0025] It is particularly advantageous if the electric motor is an internal rotor. Furthermore, it is preferable if the electric motor is a permanent magnet synchronous motor. Such electric motors are characterized by their longevity and high efficiency.

[0026] The object with regard to the cleaning device is achieved by providing a cleaning device for cleaning sensors of a vehicle, which comprises a motor according to the invention or a stator according to the invention.

[0027] It is also preferable if a motor vehicle is provided with such a cleaning device. The motor vehicle is preferably a motor vehicle with external sensors that can be cleaned using the cleaning device according to the invention. This ensures that the vehicle's sensors are operational. The invention is particularly advantageous if the motor vehicle is an autonomously operable motor vehicle whose sensors are required for the autonomous operation of the motor vehicle. In this way, the cleaning device contributes to the functional reliability of the motor vehicle.

[0028] The object with regard to the method is achieved in that a method for producing one of the devices according to the invention, in particular the stator according to the invention, the electric motor according to the invention and the cleaning device according to the invention, is provided, wherein the method comprises completely encapsulating the stator with an insulating compound, winding every second stator tooth by means of a stator winding, completely encapsulating the stator with a plastic compound and forming convection channels between the stator winding of a wound stator tooth and an unwound stator tooth, preferably during the encapsulation of the stator with the plastic compound. The devices according to the invention can be produced by this method. The method steps preferably take place in the specified order.When the stator is completely overmolded with the plastic compound, the entire stator winding and / or the entire insulating compound is preferably overmolded.

[0029] Advantageous further developments of the present invention are described in the subclaims and in the following description of the figures.

[0030] Short description of the drawings

[0031] The invention is explained in detail below using exemplary embodiments with reference to the drawings. In the drawings:

[0032] Fig. 1 a vehicle, and

[0033] Fig. 2 shows a sectional view of an electric motor according to the invention. Preferred embodiment of the invention

[0034] Figure 1 shows a vehicle 1 comprising sensors that can be cleaned by means of a cleaning device 2 according to the invention. The cleaning device 2 comprises an electric motor 3 according to the invention, which is designed as a permanent magnet synchronous machine and comprises a stator 4 according to the invention.

[0035] Figure 2 shows a sectional view of the electric motor 3 from Figure 1. The section runs perpendicular to a rotational axis of a rotor 6 of the electric motor 3. The stator 4 according to the invention can be seen, which is electrically insulated from a stator winding 5 and a plastic compound 10 by means of an insulating compound 4a. It can also be seen that convection channels 7 for cooling the stator by means of free convection are formed through the plastic compound 10. It can also be seen that only every second stator tooth 11 of the stator 4 is wound by the stator winding 5. The stator winding 4 is a concentrated winding. The convection channels 7 are each arranged between the stator winding 5 of a wound stator tooth 11 of the stator 4 and a wound stator tooth of the stator 4.By means of the plastic compound 10, a stator housing 8 is further formed, which has a fastening 9 by means of which the stator 4 is fastened to a periphery.

[0036] The embodiments of Figures 1 to 2 are in particular not restrictive in nature and serve to clarify the inventive concept.

[0037] List of reference symbols

[0038] 1 vehicle

[0039] 2 Cleaning device 3 Electric motor

[0040] 4 Stator

[0041] 4a Insulating compound

[0042] 5 Stator winding

[0043] 6 Rotor 7 Convection channel

[0044] 8 Stator housing

[0045] 9 Fastening

[0046] 10 plastic compound

[0047] 11 stator tooth

Claims

Patent claims 1 . Stator (4) for an electric motor (3), wherein the stator (4) has inwardly directed stator teeth (11), wherein only every second stator tooth (11) is wound by means of a stator winding (5), characterized in that the stator (4) is completely encapsulated by means of a plastic compound (10).

2. Stator (4) according to claim 1, characterized in that a convection channel (7) is formed between the stator winding (5) of at least one wound stator tooth (11) and an adjacent, unwound stator tooth (11).

3. Stator (4) according to claim 2, characterized in that the convection channel (7) extends over the entire length of the stator (4).

4. Stator (4) according to claim 2 or 3, characterized in that the stator (4) comprises several convection channels (7).

5. Stator (4) according to one of the preceding claims, characterized in that material-locking connections between electrical conductors are overmolded by means of the plastic compound (10).

6. Stator (4) according to one of the preceding claims, characterized in that a stator or electric motor housing (8) is formed by means of the plastic mass, which in particular has connecting openings for forming a fastening (9) to a periphery.

7. Stator (4) according to one of the preceding claims, characterized in that the stator (4) is electrically insulated from the plastic mass (10) and / or the stator winding (5) by means of an insulating mass (4).

8. Electric motor with a stator (4) according to one of the preceding claims.

9. Cleaning device (2) for cleaning sensors of a vehicle (1), comprising an electric motor (3) according to claim 8 or a stator (4) according to one of claims 1 to 7.

10. A method for producing a device (2, 3, 4) according to one of the preceding claims, comprising the following method steps: - Completely overmolding the stator (4) with an insulating compound (4a), - Winding every second stator tooth (11) by means of a stator winding (5), - Completely encapsulating the stator (4) with a plastic compound (10), - Forming convection channels (7) between the stator winding (5) of a wound stator tooth (11) and an unwound stator tooth (11), preferably during the encapsulation of the stator (4) with the plastic compound

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