Electric motor with housing part and fan hood

Abstract

Electric motor with housing part, wherein a fan hood (1) is attached to the housing part, wherein the fan hood (1) is detachably attached to the housing part by means of fastening screws, wherein the fan hood (1) has a layered structure in which at least one damping layer is provided between two sheet metal layers, wherein an electrically conductive material component is provided in the damping layer, wherein rubber elements are arranged between the housing part of the electric motor and the fan hood (1) and / or a rubber element is arranged between the fan hood (1) and the screw head of one of the fastening screws.

Description

[0001] The invention relates to an electric motor with a housing part and a fan hood.

[0002] It is known to provide a fan hood at the axial end region of electric motors to form a housing for a fan integrated in the motor or attached to the motor.

[0003] Converter systems comprise a grid-connected rectifier, whose unipolar output voltage is also referred to as the DC link voltage. This voltage supplies an inverter, which in turn powers an electric motor. In generator mode, energy is fed from the motor into the DC link via the inverter. Excess energy in the DC link is dissipated via a braking resistor or fed back into the grid by means of a complex regenerative braking system.

[0004] The invention is therefore based on the objective of further developing an electric motor with lower environmental emissions.

[0005] According to the invention, the problem is solved in the electric motor according to the features specified in claim 1 and in the fan hood according to the features specified in claim 11.

[0006] Important features of the invention for the electric motor are that it is provided with a housing part, where a fan hood is attached to the housing part, wherein the fan hood has a layered structure in which at least one damping layer is provided between two sheet metal layers.

[0007] An advantage of this is that the structure-borne sound waves that can be introduced into or propagate within the fan housing can be reduced by damping and by reducing the resonant structure. Thus, the power radiated from the surface of the fan housing in the form of airborne sound can be reduced. This, in turn, reduces environmental emissions.

[0008] In an advantageous embodiment, a fan cover is detachably attached to the housing part, in particular by means of fastening screws. An advantage of this is that simple and cost-effective fastening means can be used.

[0009] In an advantageous embodiment, the damping layer is a polyacrylate resin layer, in particular a partially cross-linked one. An advantage of this is that effective damping of structure-borne sound waves can be achieved.

[0010] In an advantageous embodiment, an electrically conductive material component is provided in the damping layer, in particular iron phosphide. It is advantageous that grounding of the two sheet metal layers can even be achieved via a ground connection of the motor housing.

[0011] In an advantageous embodiment, a material-bonded connection of the sheet metal layers is provided by means of the damping layer. It is advantageous that a high damping of structure-borne sound vibrations can be achieved by means of the connection of the parallel but spaced-apart sheet metal layers, in particular of vibrations that cause deflections of the sheet metal layers in the direction of the normal direction of the sheet metal.

[0012] In an advantageous embodiment, the fan housing is cylindrically shaped in a first axial region and has a circumferentially wave-like shape in a further axial region. An advantage of this is that resonance vibrations can be reduced. Because of the unequal shape in different axial regions, a resonance vibration can develop in one axial region; however, this does not correspond to a resonance vibration in the other axial region. Thus, the resonance vibration can only build up to a limited extent. Furthermore, the resonance vibration is mitigated by the layered structure.

[0013] In an advantageous embodiment, a grille is provided at the axial end region of the fan housing facing away from the motor. This grille has openings for the passage of airflow from the fan, which is completely or at least partially enclosed by the fan housing. It is advantageous that the fan housing allows cooling air to flow through it, while also providing protection against contact. Despite the layered structure, the openings can be manufactured by stamping. For this purpose, the openings are made with a diameter of more than 1 mm.

[0014] In an advantageous embodiment, the recesses are made so small that a human finger cannot be inserted through them. This is advantageous because it ensures protection against contact.

[0015] In an advantageous embodiment, rubber elements are arranged between the housing part of the electric motor and the fan housing, and / or a rubber element is arranged between the fan housing and the screw head of the fastening screw, in particular so that the clamping force of the fastening screw is transmitted from the screw head to the fan housing via the rubber element. An advantage of this is that further damping occurs even when vibrations are introduced by the motor. The housing is effective on the fan cover.

[0016] In an advantageous embodiment, the housing part is designed as a stator housing or flange part of the electric motor. An advantage here is that the fan cover can be directly attached to the motor housing.

[0017] Important features of the fan housing are that the fan housing has a layered structure in which at least one damping layer is provided between two sheet metal layers. In particular, the fan housing is intended for an electric motor described above.

[0018] An advantage of this is that all vibrations propagating along the sheet metal are dampened. This reduces the radiation of sound into the surrounding air. This is particularly beneficial because energy is introduced into the damping layer when the sheet metal deflects and thus bends.

[0019] In an advantageous embodiment, the fan hood has fastening areas at its axial end region, in particular recesses provided in the area of ​​the edge of the fan hood. The advantage here is that a connection is made in a simple manner and no separate additional components are required.

[0020] Further advantages arise from the dependent claims.

[0021] In the inverter system with adapter that supplies the motor, it is important that the adapter is provided for connecting the intermediate circuits of inverters.

[0022] An advantage of this is that adapters of different sizes can be coupled to each other via their intermediate circuit, thus enabling energy exchange between motor and generator drives via the intermediate circuit. Smaller drives can also be coupled to larger ones, so that different cable routing technologies, such as busbars (i.e., rigid structures) and power cables (i.e., more flexible and therefore vibration-damping structures than busbars), can be connected. This connection is achieved by means of the adapter and its design.

[0023] Further advantages arise from the dependent claims. Reference symbol list 1 fan hood 2 area with a wavy appearance in the circumferential direction 3 Grid with cutouts 4 Mounting area

[0024] The invention will now be explained in more detail with reference to illustrations: Figure 1 shows a fan cover according to the invention in an oblique view. This fan cover 1 is screwed onto a housing part of an electric motor in its mounting areas 4 by means of fastening screws, i.e., it is detachably connected.

[0025] Thus, a fan provided at an axial end region of the electric motor can be enclosed by the fan housing 1, forming a housing. The grille 3 of the fan housing, located at the axial end region furthest from the motor, is provided with recesses so that the cooling airflow is admitted or discharged by the fan housing. The recesses are therefore designed to be so small as to provide protection against contact, i.e., a human little finger cannot fit through them.

[0026] The fan hood is made of an electrically conductive sheet metal, which is thus grounded, in particular via the motor housing if the latter is provided to be electrically grounded.

[0027] Furthermore, the fan hood 1 has an axial, circumferentially wave-shaped area 2, which is thus designed to dampen vibrations and increase the stiffness of the fan hood.

[0028] The sheet metal is constructed from two sheet metal layers, in particular steel sheet metal layers, between which a damping layer is provided, in particular a polyacrylate resin layer, which is partially cross-linked. The damping layer is made electrically conductive by means of additives, such as iron phosphide, whereby the two sheet metal layers are electrically connected to each other and thus the entire fan hood is grounded.

[0029] This construction allows for a particularly effective vibration damping effect. The layered structure of the sheet metal enables a high damping effect for vibrations. In particular, bending and extensional vibrations are strongly damped, since the damping layer connects the two sheet metal layers, especially by a material bond.

[0030] Preferably, the fan is passive, i.e., it comprises a fan wheel which is non-rotatably connected to the rotor shaft of the electric motor. Alternatively, an active fan, i.e., a fan comprising its own electric drive, is also possible. In the Fig. 1 shows a converter of a converter system according to the invention.

[0031] In a converter system, intermediate circuits of different sizes can be connected to one another. Each intermediate circuit comprises an upper and a lower intermediate circuit potential, and the unipolar voltage prevailing between these potentials, in particular DC voltage, can supply a respective inverter stage comprising half-bridges of controllable power semiconductors, which is provided for generating single- or multi-phase AC voltage, from which an electric motor with the fan hood according to the invention can be supplied.

[0032] The unipolar voltage is generated from a mains-powered rectifier during motor operation. During generator operation of the motor, energy is supplied from this rectifier to the intermediate circuit.

[0033] Energy balancing is now possible by connecting the intermediate circuits of different converters. In the first converter, the intermediate circuit is implemented using busbars.

[0034] Second converters, which are smaller in size and therefore have a lower maximum output power, also have a DC link to which further converters can be connected. However, instead of busbars, simple round cables are used for the upper and lower DC link potentials. Since the round cables are more elastic By using rigid busbars, vibration damping is already achieved, and the motor is significantly decoupled from the inverter in terms of vibration. An adapter is provided to connect the intermediate circuits of the first inverter, with one busbar each for the upper and lower intermediate circuit potential. Each of these busbars can thus be connected, in particular screw-connected, to corresponding busbars provided in the first inverter that protrude from the recess. An insulating foil is provided between the busbars, which also reduces vibration and increases the electrical insulation distance, thereby lowering the critical voltage value at which breakdown occurs.

[0035] The further first converter to be connected again has a similar recess to which the adapter can be connected by means of its busbars.

[0036] For the insertion of the connecting screws, elongated holes are provided in the busbars, in particular elongated holes whose longer side is located in the direction of the connection direction determined by the adapter. In this way, length compensation is possible.

[0037] For connection with the round cables of the further second converters, the busbars are extended perpendicular to the connection direction by means of intermediate circuit adapters and are provided with a recess so that a connecting screw can be passed through, with which an eyelet can be attached, to which the electrical conductors of the round cable can be soldered.

[0038] Thus, smaller-sized converters can be easily provided below the larger-sized converters with busbars.

Claims

[1] Electric motor with housing part, where a fan hood is attached to the housing part, characterized by the fact that The fan hood has a layered structure in which at least one damping layer is provided between two sheet metal layers. [2] Electric motor according to at least one of the preceding claims, characterized in that a fan hood is detachably attached to the housing part, in particular by means of fastening screws. [3] Electric motor according to at least one of the preceding claims, characterized in that the damping layer is a polyacrylate resin layer, in particular a partially cross-linked one. [4] Electric motor according to at least one of the preceding claims, characterized in that an electrically conductive material component is provided in the damping layer, in particular iron phosphide. [5] Electric motor according to at least one of the preceding claims, characterized in that a single-material bond between the sheet metal layers is provided by means of the damping layer. [6] Electric motor according to at least one of the preceding claims, characterized in that the fan hood is cylindrically shaped in a first axial region and is wave-shaped in a further axial region in the circumferential direction. [7] Electric motor according to at least one of the preceding claims, characterized in that a grille is provided on the axial end region of the fan housing facing away from the motor, which has recesses for the passage of airflow. exhibits a fan that is completely or at least partially surrounded by the fan shroud. [8] Electric motor according to at least one of the preceding claims, characterized in that the recesses are designed to be so small that a human finger cannot be inserted through them. [9] Electric motor according to at least one of the preceding claims, characterized in that rubber elements are arranged between the housing part of the electric motor and the fan hood and / or a rubber element is arranged between the fan hood and the screw head of the fastening screw, in particular so that the clamping force of the fastening screw is transferred from the screw head to the fan hood via the rubber element. [10] Electric motor according to at least one of the preceding claims, characterized in that the housing part is designed as a stator housing or flange part of the electric motor. [11] Fan hood characterized in that the fan hood has a layered structure in which at least one damping layer is provided between two sheet metal layers. [12] Fan hood according to claim 9, characterized in that it is provided for an electric motor according to at least one of the preceding claims. [13] Electric motor according to at least one of the preceding claims, characterized in that the fan hood has fastening areas at its axial end region, in particular recesses provided in the area of ​​the edge of the fan hood.

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