WO2019110425A1

WO2019110425A1 - Electric motor

Info

Publication number: WO2019110425A1
Application number: PCT/EP2018/083044
Authority: WO
Inventors: Lakshmi Narayanan MUTHU
Original assignee: Robert Bosch Gmbh
Priority date: 2017-12-08
Filing date: 2018-11-29
Publication date: 2019-06-13
Also published as: DE102017222289A1

Abstract

The invention relates to an electric motor (10), in particular an external rotor motor, having a rotor (14), a stator (12) and a motor shaft (26), wherein the motor shaft (26) is associated with the stator (12) or the rotor (14) and has an axis of rotation (32), the rotor (14) and the stator (12) being mounted by means of at least one bearing (40, 42) in such a way that they can rotate relative to each other about said axis of rotation, and wherein the motor shaft (26) has a lateral surface (28) and a contacting element (48) is arranged between the rotor (14) and the stator (12), said contacting element being in contact with the at least one bearing (40,42) and abutting the lateral surface (28) of the motor shaft (26) and/or a contact surface of the bearing (40, 42) in such a way that it is movable, in particular rotatable, relative thereto. It is proposed that the contacting element (48) is formed at least in part from a nickel layer (52), in particular an electroless nickel layer.

Description

title

electric motor

The invention relates to an electric motor with a contact element, such a contact element and a bearing with such a contact element according to the preamble of the independent claims.

State of the art

When electromechanical commutation of motors arise

electromagnetic waves, which are radiated into the environment. These occurring electromagnetic waves should be reduced.

From DE 10 2012 201 545 Al a device for shielding electromagnetic interference of an electric motor is known, which is controlled by means of a clocked signal. It is provided that the rotor is connected to the motor shaft via an electrically conductive connecting element, wherein the connecting element acts on the end face of the motor shaft and is secured to the end face of the rotor component.

Disclosure of the invention

Advantages of the invention

The invention relates to an electric motor, in particular a

External rotor motor, comprising a rotor, a stator and a motor shaft, wherein the motor shaft is associated with the stator or the rotor and having a rotation axis about which rotor and stator are rotatably supported by at least one bearing, and wherein the motor shaft has a lateral surface and between rotor and stator a contacting element is arranged, which in Contact with the at least one bearing is and on the lateral surface of the motor shaft and / or a contact surface of the bearing to this movable, in particular rotatable, is applied. It is suggested that the

Kontaktierelement is at least partially formed of a nickel layer, in particular a chemical nickel layer, or at least one such nickel layer.

The electric motor according to the invention with the features of the independent claim has the advantage that the contacting element particularly

save space and easy to install. By using a Kontaktierlementes, which is at least partially formed of a nickel layer, which is optimized in terms of their sliding properties and at the same time has a good electrical conductivity, friction between the contact element according to the invention and rotating components, such as the rolling bearing and / or the motor shaft are minimized and at the same time a stable ohmic connection to compensate for potential differences between the rotor and stator

to be provided. Such minimization of friction thus has an advantageous effect on the resulting friction losses, the heat developments and the

Wear of such Kontaktierelementes. In addition, the Kontaktiereiement invention can due to its small size

save space and without additional adjustments to the electric motor, integrated in existing systems or even retrofitted. Furthermore, such a contacting element can advantageously protect the interior of the bearing from solid or liquid contaminants. By the integral

Construction of the electric motor according to the invention, in which both the

Function of the seal of the bearing as well as the compensation of

Potential differences are integrated in a component, among other things, the objective functions of weight, number of components and costs can be optimized in an advantageous manner. In the context of the present invention, an imaginary axis can be understood by a rotation axis about which a body, in particular the rotor, rotates in the sense of a rotation axis. In contrast to the axis of rotation, which represents a purely imaginary axis, with reference to the present invention, the term motor shaft can be understood as an objective machine element.

In the context of the present invention, moreover, under a lateral surface of the motor shaft that surface of the motor shaft can be understood, which extends in the axial direction, that is, in the direction of the axis of rotation circumferentially.

The term lateral surface is in this case not limited to a cylindrically planar surface, rather, the lateral surface may comprise projections and recesses, which has the motor shaft.

According to an advantageous embodiment of the invention, the nickel layer is formed as a chemical nickel layer. A chemico-nickel layer is a chemically produced coating of nickel, which is deposited electrolessly on a substrate, for example, from nickel-phosphorus or nickel-boron alloys. The deposition of such a chemical nickel layer takes place in an autocatalytic process. Such a chemical nickel layer has in particular with respect to the uniformity of the layer thickness, as well as the

Corrosion resistance of the layer and the wear resistance advantages. The invention is based on the finding that such a chemico-nickel layer is advantageously suitable for dispersoids, such as PTFE particles as a matrix for the deposition of so-called dispersion layers, so that the properties of the layer in an advantageous manner to a

Electric motor occurring loads and requirements can be adjusted. According to the invention, the rotor and the stator are rotatably supported relative to one another by means of at least one bearing. For this purpose, for example, the motor shaft in the motor carrier or stator can be firmly clamped, wherein the rotor rotates in operation about the motor shaft. However, it is also conceivable that the motor shaft itself is clamped in the rotor and together with the rotor in the stator or

Engine block is rotatably mounted. According to a preferred embodiment, the electric motor is further designed as an external rotor motor. In such an embodiment, the shielding effect of the rotor itself can be used to improve the electromagnetic compatibility in an advantageous manner.

The measures listed in the dependent claims, advantageous refinements and improvements of the given in the independent claims characteristics.

According to an advantageous embodiment of the invention, it is provided that the chemical nickel layer is formed as a nickel-phosphorus alloy layer. With such a nickel-phosphorus alloy layer used according to the invention, it is possible to provide a layer in the form of a composite which is dimensionally stable, has very good tribological properties and is capable of using its electrical conductivity

Compensate for potential differences between rotor in and stator.

Of course, such a nickel-phosphorus alloy layer is not limited exclusively to the components nickel and phosphorus. So it can be provided, for example, that additional hard particles or dry lubricant particles are stored, so that the

Material properties can be optimally matched to the functionalities in an advantageous manner. According to a further advantageous embodiment of the invention, it is provided that the nickel layer comprises solid lubricant particles. The incorporation of solid lubricating particles in the nickel layer can be provided in a particularly advantageous manner, a material which synergistically has the properties of the nickel matrix and at the same time the properties of the solid lubricating particle, such as a good abrasive behavior and high

Lubricity, peculiar. According to an advantageous embodiment of the invention, it is provided that the nickel layer for this purpose comprises PTFE particles, which can reduce the coefficient of friction and thus the closure rate for the dynamic application in the electric motor according to the invention.

According to a further advantageous embodiment of the invention, it is provided that the nickel layer 20-30 vol.% PTFE particles. In a further advantageous embodiment of the invention, these PTFE particles also have a particle size between 0, l-0.3pm. In this way, a nickel layer can be provided, which on the one hand in terms of

tribological properties is optimized and on the other hand is able

Compensate for potential differences between rotor and stator.

A particularly corrosion-resistant and at the same time hard nickel layer can be provided according to a further advantageous embodiment in that the nickel-phosphorus alloy layer has a phosphorus content of 9-13 vol. % having. In particular, a range between 10-12Vol. % Phosphorus has proven to be particularly suitable.

According to a further advantageous embodiment of the invention, it is provided that the nickel layer has a layer thickness of 5-25pm. As can be deposited by means of chemical nickel plating layers whose target layer thickness can be set very accurately and which have a high dimensional stability, the opposing requirements for the electric motor, such as the compensation of the Potential differences and the costliness of the electric motor to be optimized. It has been shown that a layer thickness range between 7pm and 15pm can both be produced inexpensively, as well as being able to provide an electrical bridge of the type in question between rotor and stator.

According to a particularly advantageous embodiment of the invention, it is provided that the contacting element is formed at least in two parts and has at least one support element and at least one contact element, wherein the contact element comprises the nickel layer. Such a two-part

Embodiment of the Kontaktierelementes has regarding the retrofitting of existing systems and the flexibility of manufacturing the electric motor according to the invention decisive advantages, since such a multi-part support member can be particularly easily coated outside the electric motor and then installed as a common component in the electric motor. The chemical nickel plating also provides a non-rotatable, stable and cost-effective connection between the contact element and the support element.

In the context of the present invention can under a support element a

Basic body are understood, which is able to provide a surface for the nickel layer. Such a support member may be formed, for example, of a metallic material. However, it is also conceivable that the support element is formed from a plastic, insofar as it is suitable due to its material properties to act as a base body for the coating and it is technically feasible to chemically nickel this support element under the set boundary conditions. Furthermore, a contact element can be understood to mean such an element which, in the installed state, makes contact with rotating components of the electric motor

or abraded. According to an advantageous development of the invention, it is provided that the contacting element is designed as a sealing element for the bearing, that is to say that the contacting element seals off the interior of the bearing from the environment in the direction in which the contacting element is arranged. In this context, the term sealing element can be understood to mean, in particular, such an element, which seals the interior of the bearing substantially tightly in relation to the solids and additionally or alternatively to liquids in the environment of such an inventive

Electric motor completes. In this way, the access of solid and liquid contaminants in the camp can be advantageously prevented.

According to an advantageous development of the invention, it is further provided that the contacting and additionally or alternatively, the support member is formed as an annular disc, wherein the nickel layer abradingly abuts the end face of the bearing and additionally or alternatively thereto on the lateral surface of the motor shaft. Such a flat disc can be used in a particularly space-saving manner with optimum utilization of the available installation space.

In an advantageous development, it is also provided that the bearing is designed as a rolling bearing and having an inner ring and an outer ring, and that the contacting element is connected to the outer ring and on the inner ring movable, in particular rotatably. As a result of the electrical bridging between the inner ring and the outer ring, the distance to be covered by the contacting element according to the invention can advantageously be kept low. Although such bearings have a plurality of electrically conductive components, which are basically suitable for compensating potential differences, due to the lubrication of these bearings, however, these are not a complete electrical line safe to comply, resulting in a combination of such a rolling bearing with a contact element according to the invention for balancing

Potential differences proves to be particularly advantageous. In addition, due to the small radial distance from the axis of rotation, such a contacting element is subject to low relative speeds, which has a positive effect on the

Loading height of Kontaktierelementes and concomitantly affects its life.

In an advantageous embodiment, it is provided that the motor shaft is rotatably connected to the stator, the inner ring is rotatably connected to the motor shaft and the outer ring rests against a bearing seat, wherein the bearing seat is formed on the rotor.

According to a particularly advantageous embodiment of the invention, it is provided that the contacting element or the support element is formed as part of the rolling bearing. Such an embodiment has advantages in particular with regard to the number of components and the space required.

It has proved to be particularly advantageous if the support element is designed as a cover plate of the rolling bearing. Furthermore, it is provided that this cover plate is coated with a nickel layer or chemical nickel layer such that the nickel layer abradingly abuts against rotating components. Due to the good tribological properties of

According to the invention nickel layer friction losses can be minimized at the grinding system, at the same time, such a contacting element is advantageously able to compensate for potential differences between the rotor and stator and provide a seal of the interior of the bearing.

In an advantageous embodiment of the invention, the support element is further designed as Federeiement. Such a spring element may be, for example, an elastic beam, which contacts the motor shaft radially or axially. By applying the inventive lubricious nickel layer in the region of this Contacting can be minimized in such an embodiment advantageously squeaking noises and friction losses.

The contact element according to the invention is particularly suitable for being used in such an electric motor which has a stator and a rotor and a motor shaft. Due to its embodiment with at least one support element and at least one contact element, which is movable, in particular rotatably applied to at least one rotating component of the electric motor and which a

Nickel layer, in particular having a chemical nickel layer, the contacting element according to the invention in a particularly advantageous manner

Derive interference radiation and act as a sealing element for at least one bearing of the electric motor. At the same time, the functional integration of the seal and contacting enables cost optimization and quick and easy installation. For this purpose, it is particularly advantageous if the contacting element and additionally or alternatively also the support element is designed as an annular disc. Preferably, the contacting element is designed to

derive electromagnetic interference. In this way, the emission of unfavorable noise can be reduced.

The contact element according to the invention is particularly suitable for being used in a bearing, in particular in a rolling bearing, which has a cover plate. Due to the embodiment of the bearing, in which this cover plate is formed as a support member, wherein the support member has a nickel layer which abradingly abuts a bearing surface of the bearing, the bearing according to the invention can compensate for potential differences between the rotor and stator in an advantageous manner and is in relation to the Environment formed sealed. drawing

Embodiments of the invention are illustrated in the figures and explained in more detail in the following description. Show it:

Figure 1 is a schematic sectional view of an inventive

Electric motor with a contact element according to the invention,

FIG. 2 shows a section of the electric motor according to the invention in an enlarged view analogously to FIG. 1,

Figure 3 is a perspective view of an inventive

Contacting element according to FIGS. 1 and 2,

FIG. 4 shows a detail of the electric motor according to the invention in accordance with a second embodiment,

Figure 5 is a perspective view of an inventive

Contacting element according to FIG. 4,

6 shows a detail of the electric motor according to the invention according to a further embodiment with a bearing according to the invention,

Figure 7 shows a detail of the electric motor according to the invention according to a further embodiment.

description

FIG. 1 shows a sectional view of an electric motor 10 embodied by way of example as an external rotor motor. The electric motor can in particular as

Fan motor in HVAC systems or for cooling an internal combustion engine in a vehicle or for driving a fan, a gearbox, a pump or an actuator can be used.

The electric motor 10 has a fixed part, the stator 12 and a

circulating part, the rotor 14 on. An electric motor 10 of the type External rotor motor, as exemplified in Figure 1, is characterized in that the radially inner part is fixed during operation, while the radially outer part rotates. On the stator 12, a plurality of windings 16 is arranged. The rotor 14 in turn has magnets 18. Will the

Windings 16 are traversed by current, this generates the magnetic field of the electric motor 10.

It should be noted that the electric motor 10 is shown in Figure 1 only schematically, since structure and functionality of a suitable electric motor are well known in the prior art, so here for the purpose

Scarcity and simplicity of description on an in-depth

Description of the electric motor 10 is omitted. Furthermore, it should be noted that the electric motor 10 merely by way of example and not for

Restriction of the invention is shown as an external rotor motor, since the

Invention can also be found in an internal rotor motor application.

The windings 16 of electric motors are fed in operation usually with pulse width modulated signals that can cause interference. The electromagnetic interference occurs here usually at the

Windings 16 or the magnet 18. Starting from the windings 16 or magnets 18, the interference radiation can lead to disruption of other electronic systems and components which are arranged in the vicinity of the electric motor 10. In addition to influencing the

Environmental components by the electric motor 10 may affect the electric motor 10 in its functionality in the reverse manner and interference from the environment. The electric motor 10 according to the invention should therefore shield the windings 16 and magnets 18 as possible in all directions.

In an electric motor 10 of the type of external rotor, as shown in Figure 1, such a shield can inter alia by a as close as possible to the stator 12 arranged rotor 14 can be achieved. As can be clearly seen in Figure 1, the rotor 14 is formed substantially cup-shaped. This cup-shaped design of the rotor 14 forms a shield for the windings 16 and magnets 18, which are arranged within the cup-shaped rotor 14. The pot-shaped rotor 14 has for this purpose a radially extending in the first portion 20. This first portion 20 of the rotor 14 forms the bottom of the cup-shaped rotor 14. In addition to the first portion 20, the rotor 14 has a second portion 22 which is arranged on the outer edge of the rotor 14 and a, extending in the axial direction, circumferential side wall of the cup-shaped rotor 14 forms.

The open area of the rotor 14 opposite the bottom 20 of the pot-shaped rotor 14, as can be clearly seen in FIG

Motor carrier 24 shielded. The arrangement of the cup-shaped rotor 14 and acting as a cover motor carrier 24 results in a

Substantially closed space, which is shielded in all directions by electrically conductive surfaces.

In the embodiment shown in Figure 1, the motor shaft 26 is rotatably connected to the motor carrier 24 and thus associated with the stator 12. Such a rotationally fixed connection can be provided in particular by injecting the motor shaft 26 into the motor carrier 24. As shown in Figure 1, the motor shaft 26 has a free end 30 and a rotation axis 32 about which the rotor 14 and the stator 12 are rotatably mounted to each other. Furthermore, the

Motor shaft 26 extending in the axial direction, circumferential lateral surface 28. As already mentioned, the invention is not such, here

illustrated embodiment with a rotationally fixed in the stator 12 arranged motor shaft 26 limited. Rather, it is also conceivable that the motor shaft 26 is rotatably clamped in the rotor 14 and correspondingly the motor shaft 26 is associated with the rotor 14. As shown in Figure 1, the axis of rotation 32 extends in the sense of an infinitely extending imaginary straight line in particular centrally through the motor shaft 26 and corresponds to the central axis of the motor shaft 26. For rotatable mounting of the rotor 14 relative to the stator 12 about the axis of rotation 32 points the pot-shaped rotor 14 on its side facing the motor shaft 26 on a bearing seat 36 which extends in the axial direction. Inside the bearing seat 36 of the rotor 14, a bearing 38 is arranged. As shown in Figure 1, the bearing 38 has two rolling bearings 40, 42, wherein both roller bearings 40, 42 sit with their respective outer ring 44 in the bearing seat 36 of the rotor 14 and with its corresponding inner ring 46 on the motor shaft 26.

In order to prevent the rotor 14 from assuming the function of a high-frequency antenna and possibly worsening the interference problem, the rotor 14 must be contacted with a ground potential 34. For this purpose, the rotor 14 must be electrically conductively connected to the motor shaft 26, which in turn is pressed into the motor carrier 24 and thus abuts the ground potential 34. Such a coupling between the rotor 14 and the motor shaft 26 can not be provided via the roller bearings 40, 42 as a rule, since they have an oil-filled bearing gap with the result that no sufficiently stable ohmic connection can be provided ,

Nevertheless, a sufficiently stable connection between the rotor 14 and

To provide motor shaft 26, an electrically conductive contacting element 48 is disposed between the stator 12 and the rotor 14. The contacting element 48 effects the reduction of potential differences between the rotor 14 and the stator 12 of the electric motor 10 and according to the invention is formed at least partially from a nickel layer 52. According to the invention, such a nickel layer 52 may be deposited both electrolytically from nickel electrolytes, but it is also conceivable that the nickel layer 52 may be formed by means of a chemical Nickel plating is applied. In the case of such a chemically deposited nickel layer 52, this is referred to as a so-called chemical nickel layer.

According to an advantageous development of the invention, the nickel layer 52 is formed as a chemical nickel layer. Such a chemico-nickel layer 52 has advantages in particular with regard to the uniformity of the layer thickness, as well as the corrosion resistance of the layer and the wear resistance against electrolytically produced nickel layers 52. The chemico-nickel layer is an alloy layer which generally comprises nickel and phosphorus in the majority of cases, so that a nickel-phosphorus alloy layer is mentioned here. However, it should be expressly mentioned at this point that, in addition to such a nickel-phosphorus alloy layer, it is also possible to use nickel-boron alloy layers. Such nickel-boron alloy layers are generally deposited by means of so-called borates.

In both nickel-boron alloy layers and nickel-phosphorus alloy layers, the nickel layer 52 is de-energized in one

deposited chemical process. The autocatalytic process is based on a redox process, which is due to the catalytic oxidation of the

Reducing agent on a metallic surface, associated with the reduction of deposited metal ions is characterized. Such a chemical

Nickel deposition according to the invention is a wet-chemical reduction process, which is usually activated catalytically and thermally. The electrolytes used for producing the chemical nickel layer 52 according to the invention, in this case have nickel ions, which are reduced on the surface of the supporting body to be coated to nickel atoms. The electrons necessary for such a process become in contrast to a galvanic one

Deposition not provided by an external power source, but by a corresponding reducing agent. It should be expressly mentioned at this point that this may lead to co-deposition of further elements due to side reactions of the reducing agent.

With the nickel-phosphorus alloy layer 52 according to the invention, a layer formed as a composite material can be provided, which is dimensionally stable, has very good tribological properties and is capable of compensating potential differences between rotor 14 and stator 12 due to their electrical conductivity.

According to a particularly preferred embodiment of the invention, the nickel-phosphorus alloy layer 52 comprises PTFE particles. These PTFE particles are inventively distributed in the nickel-phosphorus matrix, so that it can be assumed here of a composite material. Since PTFE, including polytetrafluoroethylene, has a very low coefficient of friction, the incorporation of PTFE into the nickel-phosphorus alloy layer 52 can advantageously minimize wear and abrasion in the area of the rotatable abutment. There are two effects to the significant reduction in wear. On the one hand, the built-in PTFE particles prevent adhesive wear due to the low coefficient of friction, and on the other hand, abraded PTFE particles form a dry lubricating film between the friction partners.

It should be mentioned at this point that others too

Solid lubricant particles or dry lubricant particles are conceivable. For example, the incorporation of hexagonal boron nitride into the nickel-phosphorus alloy layer 52 has proven to be particularly suitable. The macroscopically hexagonal particles, which are in the form of platelets, are made up of stacked layers of hexagonal symmetry, which can easily slide against each other when shear forces occur. In addition to hexagonal boron nitride, it is also conceivable that known solid lubricants such For example, find graphite and molybdenum disulfide application. In addition, it is also conceivable that perfluoroalkoxy polymers are used as solid lubricant particles, which have advantages in terms of protection against adhesive wear and the prevention of stick-slip behavior.

Of course, in addition, other hard materials, such as silicon carbide, boron carbide or diamond may be incorporated in the nickel-phosphorus alloy layer 52, which may for example have a positive effect on the hardness of the alloy layer.

Hereinafter, the fixedly clamped end 28 of the motor shaft 26 facing rolling bearing as the first roller bearing 40 and the free end 30 of the motor shaft 26 associated rolling bearings referred to as the second rolling bearing 42.

It should be noted at this point that the bearings 40, 42 shown in Figure 1 are shown by way of example only as a rolling bearing. Thus, it is also conceivable that such contacting element 48 according to the invention is used in an electric motor 10 which is mounted by means of at least one slide bearing. Due to the lubrication gap, which is filled to provide the hydrodynamic lubrication usually with oil or grease, plain bearings are in

Generally not suitable to provide a sufficiently stable ohmic connection between the stator 12 and rotor 14, so that an application of the contacting element 48 is advantageously suitable for this

Electric lubrication gap to bridge.

It should also be noted at this point that the rolling bearing is shown in Figure 1 by way of example only and not to limit the invention as a ball bearing. So it is also conceivable that other basic forms of rolling bearings, such as cylindrical roller bearings, needle roller bearings or tapered roller bearings can be used. All of these rolling bearing forms is common, however, that between the inner ring 46 and an outer ring 44 rolling body the Reduce frictional resistance and they are due to the lubrication or their nature are not able to provide a sufficiently stable ohmic connection between the rotor 14 and the stator 12.

As can be seen in Figure 1, the outer ring 44 of the first bearing 40 is clearly fixed in the axial direction in the embodiment shown here. For this purpose, the outer ring 44 of the first roller bearing 40 is fixed at its free end 30 of the motor shaft 26 facing side via a spacer sleeve 49. The function of securing in the axial direction of the outer ring 44 on the side facing away from the free end 30 of the motor shaft 26 takes over the bearing seat 38.

As can also be seen in FIG. 1, the second bearing 42 assumes the function of a fixed bearing, that is, it is capable of unambiguously positioning the motor shaft 26 in the axial direction. For this purpose, the second bearing 42 must be able to absorb both radial and axial forces and guide it into the surrounding construction. In the embodiment shown in Figure 1, the inner ring 46 of the second bearing 42 is fixed for this purpose on its the free end 30 of the motor shaft 26 facing side via a locking ring 50 on the motor shaft 26.

Of course, an inventive electric motor 10 is not limited to an axial fixation of the inner ring 46 via a locking ring 50. It can also other security elements, such as nuts or

Be provided locking washers. In order to take over the function of a fixed bearing, and the outer ring 44 of the second bearing 46 in the axial direction, that is in the extension direction of the rotation axis 32, fixed.

In addition to the spacer sleeve 49, the function of securing in the axial direction of the outer ring 44 assumes a speed groove 51.

It should also be mentioned at this point that the bearing assembly and securing the two rolling bearings 40, 42, as shown in Figure 1, in a variety of types and Modified or modified, without departing from the spirit. Thus, it is also conceivable, in particular, that the contacting element 48 is arranged on the second bearing 42. In such an embodiment, it is conceivable, for example, that the speed groove 51 assumes the function of the contacting element 48 according to the invention in addition to its supporting function. Furthermore, it is also conceivable that the contacting element 48 may be arranged on the end face 60, facing away from the free end 30 of the motor shaft 26, of the respective roller bearings 40, 42. Moreover, the invention is not limited to an embodiment with only one contacting element 48. For example, it is also possible that a corresponding one of the two rolling bearings 40, 42

Contacting element 48 is arranged.

Figure 2 shows a section of the electric motor 10 according to the invention analogous to Figure 1. As already explained, the motor shaft 26 is rotatably mounted in the stator 12. For rotatably supporting the rotor 14 with respect to the stator 12 to the

Rotary axis 32 is formed on the rotor 14 on its side facing the motor shaft 26 a bearing seat 36. At this bearing seat 36 of the outer ring 44 of the first bearing 40 abuts. The inner ring 46 of the same bearing 40 is rotatably connected to the motor shaft 26.

In order to compensate for potential differences between the stator 12 and the rotor 14, a contacting element 48 is provided according to the invention, which is in contact with the rolling bearing 40 and, according to the embodiment of the invention shown in Figure 2, rotatably abutting or rubbing on the end face 60 of the rolling bearing 40. As can be seen in FIG. 2, the end face 60 of the roller bearing 40 represents that surface which is essentially perpendicular to the imaginary axis of rotation 32. As an alternative to such an embodiment, in which the contacting element 48 abuts the end face 60 of the bearing 40 in a grinding manner, it is also conceivable for the contacting element 48 to abut the peripheral surface 28 of the motor shaft 26 in a rotatable or grinding manner. According to one further alternative embodiment of the invention, it may also

be provided that the contacting element according to the invention 48 rotatably, or abradingly abuts both on the lateral surface 28 of the motor shaft 26, and on the end face 60 of the bearing 40.

As can be clearly seen in FIG. 2, according to the embodiment of the invention shown in FIG. 2, the contacting element 48 contacts both the outer ring 44 and the inner ring 46 of the bearing 40 in a contacting manner. It is provided according to an embodiment that the contacting element 48 is pressed in its outer region via the spacer sleeve 49 on the outer ring 44 of the bearing 40, so that the contacting element 48 is arranged substantially non-rotatably on the outer ring 44 of the bearing 40. Due to the rigidity of the contacting element 48 in the axial direction, the contacting element 48 is further pressed onto the inner ring 46 of the bearing 40. Due to the planar contact of the contacting element 48 both on the outer ring 44 of the bearing 40 and on the inner ring 46 of the bearing 40, the interior 58 of the bearing 40 can be sealed in an advantageous manner in the region of the contacting element 48. In this way, the leakage of lubricants from the bearing 40 and the penetration of particles into the bearing 40 can be reduced and thus the

Bearing life can be increased. Furthermore, such, over the

Kontaktierelement 48 provided seal particularly easy to be mounted and retrofitted in existing systems. In addition, due to the optimized coefficient of friction of the chemical nickel layer 52, the sealing wear can advantageously be minimized. Due to the integral construction of the electric motor 10, in which both the function of the seal of the bearing 40,42 and the compensation of potential differences are integrated in one component, among other things, the target functions weight, number of components and costs can be optimized in an advantageous manner. As can be seen clearly in FIG. 2, the contacting element 48 is designed in two parts. According to the embodiment of the invention shown in Figure 2, the contacting element for this purpose, a support member 54 and a

Abutment element 56, wherein the abutment element 56 has the nickel layer 52. A support element 54 of the type in question may be a metal support element. However, it is also conceivable that the

Support member 54 is formed of a different material. Due to the electroless deposition in the chemical nickel plating, it is possible to coat electrically non-conductive support members 54, which are formed for example of plastic. Essential to the invention here is merely that the support member 54 has a sufficient bending stiffness and thus forms a supporting structure for contact element 56 and that the surface of the support member 54 is formed such that the chemical nickel layer 52 can be deposited without current on the support member 54. In addition to its function of providing a base body for the deposition of the nickel layer 52, it may be further provided that the support element 54 is designed such that it is able to compensate for small tolerance differences between the rotor 14 and the stator 12.

In the production of an electric motor 10 according to the invention according to the embodiment shown in Figure 2 is first in a first

Manufacturing step, the nickel layer 52 deposited on the support member 54 by means of chemical nickel plating. The nickel layer 52 preferably has a layer height 62 of 7-15 pm. Subsequently, the contacting element 48 is pushed onto the motor shaft 26 until it rests with the abutment element 56 against the inner ring 46 of the first bearing 40. Subsequently, the spacer sleeve 49 is pushed, which presses the outer portion of the Kontaktierelementes 48 against the outer ring 44. Essential to the invention here is that the

Supporting area between the outer ring 44 and the contact element 48 is designed in terms of area so large that a sufficiently stable ohmic Connection between the outer ring 44 and the contacting element 48 can be provided and that only the abutment portion 56 of the

Kontaktierelementes abrading against rotating components.

FIG. 3 shows the embodiment of the contacting element 48 according to the invention shown in FIG. 2 in a perspective view. As can be clearly seen in FIG. 3, the layer height 62 of the chemical nickel layer 52 is set in such a way that it terminates flush with the support element 54 in the axial direction. Both the contact element 56 and the support element 54 are formed according to the embodiment shown in Figure 5 as a substantially annular discs. It should be expressly mentioned at this point that it is also conceivable that the contact element 56 or the

Support member 54 have a different shape in that they are suitable to provide the appropriate functionalities.

As already explained, the nickel layer 52 may according to an advantageous

Development of the invention be designed as a nickel-phosphorus alloy layer in which PTFE particles are incorporated. A phosphorus content of

10-12Vol.% Has proven to be particularly suitable because at such a phosphorus content of the wear protection for the electric motor 10 according to the invention is considered particularly suitable. According to an advantageous embodiment of the invention, it is further provided that the nickel layer 52 between 20 vol.% And 30 vol.% PTFE particles which are preferably between 0, lpm and 0.3pm large. Storage rates above 30% vol

tribological behavior for a corresponding electric motor 10 of the type in question here not suitable because too little of the cohesive

Chemical-nickel matrix is present, whereby the particles can not be held sufficiently firmly in the layer. As already explained at the outset, it is provided according to the invention that the nickel layer 52 rotatably bears against the end face 60 of the bearing 40 or the lateral surface 28 of the motor shaft 26. Since such a nickel layer 52, in particular with the addition of certain dry lubricants can be very cost-intensive, it can be provided according to the present invention that the radial width 64 of the abutment element 56 is reduced in the radial direction, so that only on a narrow circumferential edge of the support element 54, the corresponding nickel layer 52 respectively

Chemically nickel layer is deposited. Essential to the invention, however, is that the support element 54 itself does not abrade against rotating components and here causes friction losses.

In accordance with a further embodiment of the invention, provision may additionally be made for the abutment element 56 to protrude beyond the contour of the support element 54 in the axial direction. Furthermore, it can be provided that the contact element 56 or the nickel layer 52 covers the entire radial width 66 of the support element 54. Such an embodiment is shown by way of example in FIGS. 4 and 5.

FIG. 4 shows a detail of the electric motor 10 according to FIG. 2, with the only difference that the contacting element 48 is in another

alternative embodiment is shown. The contacting element 48 from FIG. 4 now has a nickel layer 52 or a contact element 56 which covers the support element 56 on one side over the entire radial width 66. As can also be seen in FIG. 4, the contacting element 48 is rotatably connected to this contact surface 56 both on the end face 60 of the bearing 40 and on the lateral surface 28 of the motor shaft.

In the following, the rotatable, axial contacting of the Kontaktierelementes 48 with the end face 60 of the bearing 40 as the first sliding contact surface 68 and the rotatable, radial contacting of the Kontaktierelementes 48 with the lateral surface 28 of the motor shaft 26 referred to as the second sliding contact surface 70. A

Embodiment of the invention according to which it is provided that the contacting element 48 abuts both the first sliding contact surface 68 and the second sliding contact surface 70, has the advantage that in case of loss of contact with one of the two sliding contact surfaces 68, 70 of the

Potential equalization can be done via the corresponding remaining contact. In particular, a slight lifting of the contacting element 48 from the first sliding contact surface 68 can occur during operation by start-up movements or Schüttei loads, so that the corresponding radial contact can maintain the function of balancing the potential differences. In this way, the reliability of the electrical bridge can be increased.

Furthermore, the sealing of the bearing interior 58 with respect to the environment due to the additional sealing surfaces can be provided with particular preference by means of such, on both sliding contact surfaces 68, 70 contacting element 48.

FIG. 5 shows the contacting element 48 shown in FIG

perspective view. As can be clearly seen in FIG. 5, the contacting element 48 according to the invention has a nickel layer 52 which covers the entire width of the support element 54. In the assembled state, therefore, the abutment element 56 contacts both the inner ring 46 and the outer ring 44 in a contacting manner. Due to the low coefficient of friction of the contact element 56, it may be in such an embodiment of the invention that the

Spacer sleeve 49 can not provide a sufficiently large surface pressure to provide a rotationally fixed connection between the outer ring 44 and the abutment member 56 so that relative movements between abutment member 56 and the outer ring 44 may occur. However, this does not affect the compensation of potential differences or only insignificantly. As already explained, according to the embodiment illustrated in FIGS. 4 and 5, the contacting element 48 abrades both the first sliding contact surface 68 and the second sliding contact surface 70. In order nevertheless to be able to ensure a simple sliding of the contacting element 48 onto the motor shaft 26 during assembly, the contacting element according to an advantageous development has an inner diameter whose smallest dimension is greater than or equal to the largest dimension of the diameter of the motor shaft 26.

FIG. 6 shows a further advantageous embodiment of the invention. Figure 6 shows a section of an electric motor 10 according to the invention, as already shown in Figures 2 and 4, with the difference that the contacting element 48 is now formed as part of the bearing 40 itself. As can be clearly seen in FIG. 6, the roller bearing 40 has a cover disk 76 on its side facing the free end 30 of the motor shaft 26. This cover plate 76 according to the invention forms the support element 54 for the nickel layer 52.

As can be seen in Figure 6, the cover plate 76 is arranged according to the embodiment shown in Figure 6 on the outer ring 44 and extends in the radial direction as far in the direction of the inner ring 46, that only a narrow gap remains between the inner ring 46 and the cover plate.

According to the invention, it is now provided that this cover disk 76 is coated with a nickel layer or chemical nickel layer in such a way that the nickel layer abrades the inner ring 46 of the rolling bearing 40. Due to the good tribological properties of the invention

Nickel layer friction losses can be minimized at the abrasive system, at the same time, however, such a contact element 48 is able to compensate for potential differences between the rotor 14 and stator 12 and a Seal the interior 56 of the bearing 40 to provide. This functional integration has an advantageous effect on the number of components of such an electric motor 10 and the space required.

According to the embodiment of the invention shown in FIG

Nickel layer 52 on the, the free end 30 of the motor shaft 26 facing side of the cover plate 76 is arranged. It should be noted at this point, however, expressly that the invention is not limited to such an embodiment

limited. Thus, for example, it is also conceivable that the nickel layer 52 or the abutment element 56 surrounds the cover plate or, alternatively, can be arranged on the side facing the interior 58 of the bearing 40.

Of course, the invention is not limited to the use of cover plates 76 as carrying elements 54. For example, it is also conceivable that other non-contacting seals of the bearings 40, 42, such as, for example, non-contacting sealing disks or baffle plates, may be designed as support elements 54. Since, as already explained, chemical nickel layers can be deposited both on metallic base bodies and on plastic base bodies, the invention is furthermore not limited to a metallic bearing part as support element 74, so that, for example

Plastic sealing washers may be suitable as support elements 54 in the sense of the invention.

According to an advantageous embodiment of the invention, it is also conceivable that additionally or alternatively to one, according to FIG. 6

arranged cover plate 76, this can be arranged on the, the free end 30 of the motor shaft 26 side facing away. In addition, it is also conceivable that such a contact plate 48 formed as cover plate 78, which has the function of the support body for the applied on the cover plate Nickel layer 52 forms, may additionally or alternatively also be arranged on the second bearing 42. It should be expressly noted at this point that the shape of the cover plate 76 is not limited to the contour shown in Figure 6. Thus, a plurality of cover plates are conceivable, insofar as they are suitable to provide the functionality of the support element 74 accordingly. In addition, such a cover plate 76,

or sealing disc, depending on the application as a single seal for the bearing 40, 42 may be provided or in addition to a further pre-seal.

Figure 7 shows a further advantageous embodiment of the invention according to which the T ragelement 54 may be formed as a spring element 78. As can be seen in FIG. 7, the support element 54 is shown in FIG

Embodiment of the invention, an integral part of a Speednut 51 for axial fixation of the bearing 42 and has a trained as a bail spring element 78, which contacts the motor shaft 28 frontally. Furthermore, provision is made for the spring element 78 to have the nickel layer 52 according to the invention in the region of the contacting, so that friction losses at the abrading abutment can advantageously be reduced.

It should be expressly mentioned at this point that formed as a support element 54 spring element 78 is not limited to such an embodiment shown in Figure 7. For example, it is also conceivable that one or more spring elements 78 can be arranged between the inner ring 46 and the outer ring 44 of the bearings 40, 42. Furthermore, it is also conceivable that such a spring element 78 radially contacts the motor shaft 26 or the lateral surface 28 of the motor shaft 26. Essential to the invention here is merely that on the support member 54, a corresponding contact element 56 is arranged, which has the nickel layer 52 according to the invention, and that this Nickel layer 52 corresponding to the rotating components of the

Electric motor 10 is arranged.

It should be noted that, with regard to the exemplary embodiments shown in the figures and in the description, a variety of possible combinations of the individual features are possible with one another. Thus, for example, the configuration of the contacting element 48 and / or the insertion element 76 can be adapted to the permissible relative speeds, coefficients of friction and squeaking noises. The design of the Kontaktierelementes 48 as a one-piece or multi-part component and the type of rotationally fixed attachment of the contacting on the rolling bearing can

Product requirements such as the cost of the component or the retrofitting of an existing system can be adjusted.

Preferably, the electric motor 10 according to the invention drives

Combustion engine cooling fan on. However, the electric motor 10 can also be used in a pump, in particular a coolant pump, or an interior ventilation system of a vehicle.

Claims

claims

1. Electric motor (10), in particular external rotor motor, with a rotor (14), a stator (12) and a motor shaft (26), wherein the motor shaft (26) is associated with the stator (12) or the rotor (14) and a Rotary axis (32) to which rotor (14) and stator (12) to each other by means of at least one

Bearing (40, 42) are rotatably mounted, and wherein the motor shaft (26) has a lateral surface (28) and between the rotor (14) and stator (12)

Contacting element (48) is arranged, which is in contact with the at least one bearing (40,42) and on the lateral surface (28) of the motor shaft (26) and / or a contact surface of the bearing (40, 42) movable to this, in particular rotatable, abuts, characterized in that the

Contacting element (48) at least partially from a nickel layer (52), in particular a chemical nickel layer is formed, or at least one such nickel layer (52).

2. Electric motor (10) according to claim 1, characterized in that the

Chemical nickel layer is formed as a nickel-phosphorus alloy layer.

3. Electric motor (10) according to one of the preceding claims, characterized

characterized in that the nickel layer comprises solid lubricant particles, in particular PTFE particles.

4. Electric motor (10) according to one of the preceding claims, characterized

characterized in that the nickel layer comprises 20-30 vol.% PTFE particles.

5. Electric motor (10) according to one of the preceding claims, characterized

characterized in that the nickel layer comprises PTFE particles with a particle size between 0, l-0.3pm.

6. Electric motor (10) according to one of the preceding claims, characterized in that the nickel-phosphorus alloy layer a

Phosphorus content of 9-13vol. %, in particular 10-12Vol. % having.

7. Electric motor (10) according to one of the preceding claims, characterized

characterized in that the nickel layer (52) has a layer thickness of 5-25pm, especially 7-15pm.

8. Electric motor (10) according to one of the preceding claims, characterized

characterized in that the contacting element (48) is formed at least in two parts and at least one support element (54) and at least one

Abutment element (56), wherein the abutment element (56) the

Nickel layer (52)

9. Electric motor (10) according to one of the preceding claims, characterized

characterized in that the contacting element (48) is designed as a sealing element for the bearing (40, 42).

10. Electric motor (10) according to one of the preceding claims, characterized

in that the contacting element (48) and / or the

Support member (54) is formed as an annular disc, wherein the

Nickel layer (52) on the end face (60) of the bearing (40, 42) and / or the lateral surface (28) of the motor shaft (26) abradingly.

11. Electric motor (10) according to one of the preceding claims, characterized

characterized in that the bearing (40, 42) is designed as a rolling bearing and has an inner ring (46) and an outer ring (44), wherein the

Contacting element (48) with the outer ring (44) is connected and on the inner ring (46) movable, in particular rotatably rests.

12. Electric motor (10) according to any one of the preceding claims, characterized in that the motor shaft (26) rotatably connected to the stator (12) is connected, the inner ring (46) rotatably connected to the motor shaft (26) and the outer ring (44 ) abuts a bearing seat (36), wherein the bearing seat (36) on the rotor (14) is formed.

13. Electric motor (10) according to one of the preceding claims, characterized

characterized in that the contacting element (48) or the support element (54) as part of the rolling bearing (40 42), in particular as a cover plate (76) of the

Rolling bearing (40, 42) is formed.

14. Electric motor (10) according to one of the preceding claims, characterized

in that the support element (54) is designed as a spring element (78).

15. contacting element (48) for use in an electric motor (10) according to one of the preceding claims, characterized in that the

Contacting element (48) has at least one support element (54) and at least one contact element (56), wherein the contact element (56) has a

Nickel layer (52), in particular a chemical nickel layer, wherein the nickel layer (52) in the installed state at the end face (60) of the bearing (40, 42) and / or the lateral surface (28) of the motor shaft (26) grinding is applied.

16. contacting element (48) according to claim 15, characterized in that the contacting element (48) and / or the support element (54) is designed as an annular disc.

17. bearing (40,42) with a contacting element (48) according to one of the preceding claims, characterized in that the bearing (40, 42) a Cover disc (78), wherein the cover plate (78) is designed as a support member (54) and wherein the support member (54) has a nickel layer (52) which abuts a contact surface of the bearing (40, 42).