DE102006016271B4 - Method of manufacturing an electric motor - Google Patents

Abstract

Method for producing an electric motor with a terminal box and stator, which comprises cooling fins (2) and fastening elements, the arrangement of the fastening elements having a two-, four- or multiple rotational symmetry, a base plate being detachably connectable to the stator by means of the fastening elements, with a Nameplates and/or rating plates and/or an electronic assembly can be releasably connected to the stator by means of additional fastening elements, the fastening means being designed as a streamlined thickening (3) of a cooling fin (2), so that the flow of cooling air between two adjacent cooling fins ( 2) is as unobstructed as possible and runs in a straight line, with at least four first of the fastening means lying in a first plane and at least four second of the fastening means lying in a second plane which is arranged perpendicularly to the first plane, so that the motor can be mounted in different orientations, where the fasteners tion elements are arranged on the stator in such a way that the base plate can be fastened to the stator in at least two orientations, i.e. in at least two different directions of the normal of the base plate, with the base plate being variably orientable and attachable relative to the terminal box by the base plate on one of the three sides of the stator can be mounted and the terminal box can be permanently provided on a fourth side, whereby initially only conical recesses are introduced as a centering aid during production in the thickenings (3) and then during assembly of the electric motor only in those used for fastening the base plate Thickenings (3) a bore is introduced, whereby those thickenings (3), which are used for fastening the base plate, have a conical depression in the area of the borehole, which serves as a centering aid when screwing in the fastening screws.

Description

The invention relates to a method for producing an electric motor.

Motors with fans for self-ventilation and cooling ribs on the stator housing are known.

From the EP 0 917 276 A1 a stator housing for electric motors is known in which a terminal box 10 reaches through a through-opening 42 in the stator housing 4 with a connecting piece 24 protruding from its through-opening 20 in the base 14 . The through-opening runs transversely to the cooling fins 40 across a region of several cooling fins ( 6 and 17 ). Sleeve-like formations 46 are provided for fastening the terminal box, which are arranged in interruptions in the cooling ribs and which engage in the extension of the axially running intermediate spaces formed by the cooling ribs. The through hole and sleeve-like formations are provided on the top and sides of the stator housing so that a terminal box 10 can be selectively attached to one or more of the three attachment points on the stator housing (col. 4, lines 4-11).

From the EP 0 917 275 A1 a stator housing for electric motors is known.

From the DE 17 28486 U a housing for electrical machines is known.

From the DE 74 24 640 U an electric motor with additional parts attached to the circumference of the motor housing is known.

The object of the invention is to further develop an electric motor with improved cooling.

According to the invention, the object is achieved in the method for producing an electric motor according to the features specified in claim 1.

Important features of the method of manufacturing an electric motor is that the electric motor includes a stator with cooling fins and fasteners,
wherein a base plate can be detachably connected to the stator by means of the fastening elements,
wherein the fastening means are designed as streamlined thickenings of cooling fins,
wherein the fastening elements are arranged on the stator in such a way that the base plate can be fastened on the stator in at least two, in particular three, orientations, in particular in at least two different directions of the normal of the base plate.

In this context, streamlined is understood to mean a profile shape of the cooling ribs with thickenings, the profile shape being obtained by cutting the cooling ribs with a coaxial, mathematically imaginary cylinder. The profile shape is streamlined, so that there is little flow resistance for the flow of cooling air.

The advantage here is that air ducts can be formed through the cooling ribs, in which air flows along the stator housing, in particular starting from a motor fan. Furthermore, the base plate can be variably oriented and attached relative to the terminal box by the base plate being mountable on one of the three sides. The terminal box can therefore be provided in a fixed manner on a fourth side. This advantageously prevents three through-openings, ie one through-opening on each side, from impeding the flow of air along the cooling fins and in particular directing it radially away from the stator housing. The streamlined shape of the fastening elements has the advantageous effect that the cooling air is laminar in the air ducts during normal operation of a motor fan, i.e. at flow speeds of 2 to 7 m/s, i.e. with a Reynolds number between 1200 and 4000 with a clear distance between the ribs with almond-shaped thickenings from 6 to 15 mm, flows. The clear distance between the ribs with almond-shaped thickening represents a characteristic length that describes the geometry. The axial length of the motors that can be used is between 0.1 m and 1 m.

In further advantageous configurations, flow velocities of 1 to 10 m/s in the air ducts are also useful. Reynolds numbers between 1000 and 5000 are also advantageous. The distance between the ribs can also advantageously be selected from 4 to 30 mm

In the case of other flow velocities, the structural dimensions of the stator housing with ribs must be selected accordingly in order to achieve a Reynolds number in the range given above. At higher flow velocities, the characteristic length should be chosen smaller so that the product of both variables remains constant, and vice versa.

Instead of air, a coolant, for example water, can also generally be provided, which flows in the air ducts. In this case, the flow velocity and the characteristic length in particular must be adjusted in such a way that the Reynolds number is in the range specified above.

In a further advantageous embodiment, the cooling ribs form air ducts in which air, in particular from an end face of the stator housing to the other, especially laminar flows.

Surprisingly, the laminar flow conditions have the particularly advantageous effect that the air flow sweeps over the entire length of the stator and is not carried away by turbulence from the air ducts and thus from the stator housing. Although the turbulence improves the cooling behavior locally, it means that parts of the stator housing are not swept over by the air flow. Thus, the cooling capacity is surprisingly reduced by the occurrence of turbulence.

In a further advantageous embodiment, connecting means, such as screws, rivets or clip means, are designed for connecting the base plate to the fastening means in such a way that they do not change the streamline shape of the cooling fins in the mounted position. In particular, blind bores or recesses are provided in the fastening means, which run in the imaginary plane through the top and bottom of the cooling fins and into which the connecting means can be inserted.

The advantage here is that the connection of the footplate to the fastening elements means that no additional parts are introduced that impede the flow of air in the air ducts. This improves engine cooling.

According to the invention, additional streamlined fastening means are provided in the cooling fins for fastening type and/or rating plates and/or electronic assemblies.

The advantage here is that additional functions and/or additional electronic functions can be easily and securely attached to the stator housing without disturbing the laminar flow in the air ducts.

According to the invention, the arrangement of the fastening elements has a two-, four- or multiple rotational symmetry.

The advantage here is that the base plate and/or nameplates and/or electronic assemblies can be mounted on one side in different orientations.

Important features of the cooling device for an electric motor are that three cooling ribs, in particular three consecutive ones in the circumferential direction, are included, of which a first and a second are provided to form a first air duct and the second and third to form a second adjacent air duct, wherein the ducts run in the axial direction, and wherein the central, i.e. second, cooling rib comprises fastening means, the side surfaces, i.e. the axially extending flank surfaces, of the cooling ribs being streamlined in order to avoid or reduce turbulence in the respective air duct, in particular continuously differentiable.

The advantage here is that an air flow between the cooling fins can be guided in a laminar manner. The constantly differentiable design of the cooling rib side faces particularly advantageously avoids turbulence, which would cause the air flow to be deflected away from the stator and thus reduce the cooling capacity. It is also advantageous that a terminal box and/or housing for electronic assemblies and/or base plates can be fastened to the stator, with these not representing any additional flow resistance for the air flow in the fastened position.

In a further advantageous embodiment, the air ducts are designed as A and B sides, ie the end faces of the stator housing, connecting linear, in particular parallel, ducts which are in particular delimited by the cooling fins transversely to the axial direction. In particular, in the air duct formed by the three cooling fins, air can advantageously be passed through in a laminar manner from the B side to the A side, or vice versa.

In this context, B-side is understood to be a side of the electric motor on which a fan or a flow source for the coolant is arranged. The A-side is understood to mean a side of the electric motor onto which the coolant flows from the B-side. The A and B sides of an electric motor are preferably described by the position of end shields, which are connected to the opposite end faces of the stator housing.

The advantage here is that the airflow for cooling sweeps over the entire length of the stator.

In a further advantageous embodiment, no objects or obstacles that increase the flow resistance are provided in the air ducts, in particular after attachment of devices to the attachment means, with blind holes being provided in particular on the attachment means, which run in the imaginary plane through the top and bottom of the cooling fins and in the fasteners can be inserted for attachment.

The advantage here is that devices can be attached to the fastening means without impeding the air flow in the air ducts.

Important features in the cooling device for an electric motor are that axially extending straight cooling fins and axially extending cooling fins with swell are included, the swells of the cooling fins with swell comprising fastening means which define at each point a tangential vector on the lateral surfaces of the straight cooling fins which is parallel to the Motor axis is, and the side surfaces of the cooling fins are streamlined, in particular continuously differentiable.

The continuously differentiable design of the side surfaces of the cooling fins, which is designed as a mathematical ideal within technical tolerances, has the advantageous effect that kinks, edges and/or steps in the side surfaces of the cooling fins are avoided. However, such kinks, edges and/or steps are known to cause turbulence in the air flow. The continuously differentiable design thus advantageously avoids the occurrence of such turbulence, leading to laminar flow conditions between the cooling fins. Deflection of the air flow away from the stator is thus advantageously avoided.

In a further advantageous embodiment, the cooling ribs extend over the length of the stator housing.

In a further advantageous embodiment, the tangential vector on the profile shape of the cooling ribs with thickening forms an angle with the motor axis of a maximum amount of 40°, preferably less than 30°.

This advantageously avoids geometric shapes of the cooling ribs, which promote the formation of turbulence in the air flow.

In a further advantageous embodiment, each cooling fin with a thickening is adjacent to two straight cooling fins.

The advantage here is that the thickenings do not protrude from two adjacent cooling fins into the common space and thus do not deflect and swirl the air flow. In a further advantageous embodiment, the axial spatial extent of the fastening means is more than twice the transverse extent of the fastening means.

The advantage here is that the fastening means have a particularly streamlined shape and thus influence the air flow between the cooling fins as little as possible.

In a further advantageous embodiment, the transverse extent of the fastening means exceeds the clear distance to at least one adjacent cooling fin.

The advantage here is that the fastening means offer a large attachment surface for devices to be fastened, in particular a base plate can thus be attached stably to the stator housing.

Important features of the electric motor with stator are that cooling fins and fastening elements are included, with further components, in particular rating plate, base plate or the like, being detachably connectable to the stator by means of the fastening elements, and with the fastening means being designed as thickenings of cooling fins, with in The air ducts formed by the cooling ribs are not provided with any further obstacles, i.e. objects and/or formations that increase flow resistance, in particular that the air flow in the air ducts flows in a laminar manner in the axial direction and does not lift off from the cooling ribs or from the space between the cooling ribs.

The advantage here is that only slight thickenings in the cooling fins are sufficient to accommodate the fasteners. Screws can thus be screwed into the cooling fins themselves and the heat can be given off to the additional component that is screwed on. In addition, the air duct covered by the additional component can be kept free between two adjacent cooling ribs by making the thickened area sufficiently small. In particular, bulges are shaped in such a way that the flow of cooling air along the cooling ribs is unimpeded or only slightly impeded as a result of the bulges. The advantage here is that the cooling, ie heat dissipation to the ambient air, is improved and the performance of the motor is increased, in particular the maximum permissible performance.

In an advantageous embodiment, the thickenings run in the direction of the cooling rib in an approximately almond-shaped or streamlined manner and are spatially less extended in the direction of the normal to the cooling rib than the distance to the next neighboring cooling rib. The advantage here is that the cooling air flow is as laminar as possible, i.e. there is as little turbulence as possible. Small turbulences, which run transversely to the direction of flow as small self-contained vortices, are already introduced by the fan and have a beneficial effect on cooling. The thickenings can be designed in such a way that the cooling air flow does not open up in the direction of the cooling fins swirls and does not lift off, i.e. does not leave the space between the cooling fins, which is crucial for cooling. The almond-shaped shape of the surface in the direction of the cooling fins can be continuously differentiated.

According to the invention, at least some of the fastening means lie in one plane. The advantage here is that the other components just described can be screwed on.

In an advantageous embodiment, at least four of the fastening means lie in one plane. The advantage here is that a base plate can be releasably connected and the motor can be mounted stably on such a mounting plate.

In an advantageous embodiment, the thickenings are spatially less extended in the direction of the normal of the cooling rib than half the distance to the next neighboring cooling rib in order to reduce the influence on the cooling air flow. The advantage here is that the cooling air flow flows within the ribs.

According to the invention, the thickenings include blind holes or centering aids, which are formed, for example, as conical recesses. The advantage here is that simple and inexpensive fasteners can be provided.

According to the invention, at least four first of the fastening means lie in a first plane and at least four second of the fastening means lie in a second plane, which is arranged perpendicularly to the first plane. The advantage here is that the motor can be mounted in different orientations.

In an advantageous embodiment, two fastening means are provided for the detachable connection to a rating plate and four further fastening means for the detachable connection to a base plate, that is to say a mounting plate, particularly in the region of the first level. The advantage here is that the rating plate or the base plate can be optionally connected.

Further advantages result from the dependent claims.

• In den 1 bis 6 ist ein mit einem erfindungsgemäßen Verfahren hergestellter Elektromotor in verschiedenen Ansichten gezeigt. Das Unterteil des zugehörigen Anschlusskastens ist in den 7 und 8 in verschiedenen Ansichten gezeigt.

The invention will now be explained in more detail with reference to figures:

• In the 1 until 6 an electric motor produced with a method according to the invention is shown in various views. The lower part of the associated junction box is in the 7 and 8th shown in different views.

The motor is designed as an electric motor and has a flange 1 with which another device to be driven, such as a gear or agitator, can be connected.

The motor has cooling ribs 2 on its stator housing, some of which have almond-shaped thickenings 3 . The fan shroud 4 is provided on the side opposite to the flange 1 . The connection box, which can also be referred to as a terminal box, is composed of a connection box lower part 5 and a connection box upper part 6, which can be connected detachably to this part, as a cover. On its outer side facing the stator housing of the motor, the terminal box lower part 5 has cams 20, which represent accumulations of material for the introduction of a bore.

Since the parts of the motor, but in particular the parts of the motor that form the housing, are designed to save as much material as possible, it is not possible to easily and stably drill a hole in the housing. Therefore, the cams 20 provide material thickenings into which the drilled holes 80 can be made from the inside of the lower part of the connection box. The shape of the cams is shark fin like. The cams are directed towards the motor and are provided on the underside of the terminal box. Without a sloping side, the strength would not be high enough. The shark fin-like shape enables high strength with slightly more material consumption than would be necessary for the bore 80 . Another surface that would run obliquely would further increase the material consumption, but would not have a correspondingly large strength-increasing effect. The borehole 80 is designed as a pre-cast blind hole. Only material around the borehole 80 is used so that the minimum amount of material is used, with only one tapered side being provided to increase strength with little material consumption.

In its housing wall, the connection box lower part 5 comprises screwed cable connections 30 for the passage of cables. The protective conductor included in these is connected to the protective conductor connection device 43 .

As an option, the rectifier module 40 is fastened with the fastening screws 41 in the lower part 5 of the connection box.

The terminal board 42 is used at least to connect the supply lines routed through the cable glands 30 to the winding wires of the stator.

The fan shroud 4 has elevations that alternate with one another in the circumferential direction on its circumference gene 100 and depressions 101, so wavy impressions in the circumferential direction in the intake of the fan cowl. In this way, noise emissions are reduced and, in addition, the rigidity of the fan hood 4 is increased. The fan cover 4 also has a stacking edge 31 running all the way around. The hoods 4 can be stacked in the warehouse to save space by means of this stacking edge 31 . The edge of the stack has an additional stiffening effect on the fan cowl 4.

The almond-shaped thickenings 3 are designed as a thickening of the cooling ribs on the stator housing for attaching the type plate, ie rating plate, or for example on another side for attaching a base plate on which the motor can be mounted. For this purpose, the almond-shaped thickenings 3 are arranged within one plane. In particular, four of these each belong together. The almond shape is designed in such a way that it impedes the flow of cooling air between two adjacent cooling fins as little as possible. For this purpose, they are approximately streamlined or correspondingly almond-shaped running along the cooling fins. The cooling fins are only slightly thicker in these areas. Advantageously, the engine is therefore better cooled than in the prior art. Because there is no thickening that impedes the flow of air between two cooling fins along the cooling fins. None of the thickenings even connects two adjacent cooling fins. Instead of introducing a blind hole, according to the invention, only conical recesses are initially to be introduced as a centering aid during manufacture. Only if a hole is actually to be provided during assembly of the engine is one drilled. But then the drilling tool is simply centered and the location of the hole is already pre-marked.

In further exemplary embodiments according to the invention, the boreholes are designed as blind boreholes.

According to the invention, those thickenings which can be used to fasten the base plate have a conical indentation in the region of the borehole as a centering aid when screwing in the fastening screws.

Instead of the rectifier module 40 other electronic circuits such as motor starters or soft starters or converters and control circuits or connection devices such as terminal strips or holding devices such as mounting rails or the like can also be connected in further exemplary embodiments according to the invention.

Reference List

1

flange

2

cooling fin

3

almond-shaped thickening

4

fan hood

5

terminal box base

6

Junction box top

20

cam

30

cable gland

31

stack edge

40

Rectifier module as an option

41

Fixing screws for option

42

clipboard

43

Protective conductor connection device

80

Hole in cam

100

increase

101

deepening

Claims (1)

Method for producing an electric motor with a terminal box and stator, which comprises cooling fins (2) and fastening elements, the arrangement of the fastening elements having a two-, four- or multiple rotational symmetry, a base plate being detachably connectable to the stator by means of the fastening elements, with a Nameplates and/or rating plates and/or an electronic assembly can be detachably connected to the stator by means of additional fastening elements, the fastening means being designed as a streamlined thickening (3) of a cooling rib (2), so that the flow of cooling air between two adjacent cooling ribs ( 2) is as unobstructed as possible and is straight, with at least four first of the fasteners lying in a first plane and at least four second of the fasteners lying in a second plane that is perpendicular to the first plane, so that the motor can be mounted in different orientations, where the be fastening elements are arranged on the stator in such a way that the base plate can be fastened to the stator in at least two orientations, i.e. in at least two different directions of the normal of the base plate, with the base plate being variably orientable and attachable relative to the terminal box by the base plate on one of the three sides of the stator can be mounted and the terminal box can be provided on a fourth side, whereby - initially in the production in the thickenings (3). only conical recesses are made as a centering aid and - then during assembly of the electric motor only a bore is made in the thickenings (3) used for fastening the base plate, with those thickenings (3) which are used for fastening the base plate being conical Have deepening in the area of the drill hole, which serve as a centering aid when screwing in the fastening screws.

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