Arrester device, rotary atomizer comprising such an arrester device, use of such an arrester device

Abstract

The invention relates to an arrester device (8) for dissipating a high-voltage potential from a rotor (2), in particular from an atomizer shaft (2) of a rotary atomizer (1) with electrostatic charging of the coating. The arrester device according to the invention comprises an arrester ring (9), which annularly surrounds the rotor (2), and at least one electrically conductive contact element (10), which is arranged on the arrester ring (9) and touches the rotor (2), in order to dissipate the high-voltage potential from the rotor (2). The invention makes provision for the arrester ring (9) together with the at least one contact element (10) to be formed in one piece as an integral component (8).

Description

[0001] DESCRIPTION

[0002] DISCHARGE DEVICE, ROTARY ATOMIZER WITH SUCH A

[0003] DISCHARGE DEVICE, USE OF SUCH DISCHARGE DEVICE

[0004] Technical field of the invention

[0005] The invention relates to a discharge device for discharging a high-voltage potential from a rotor, in particular from an atomizer shaft of a rotary atomizer with an electrostatic coating agent charge. Furthermore, the invention relates to a rotary atomizer with such a discharge device.

[0006] Background of the invention

[0007] In modern paint shops for painting automotive body components, rotary atomizers are typically used as application equipment. To increase application efficiency and avoid disruptive overspray, electrostatic paint charging is also known. This charges the spray jet of the applied paint to a high-voltage potential while the vehicle body components to be painted are electrically grounded. This ensures that the applied paint is almost completely deposited on the vehicle body components to be painted, resulting in very little overspray.

[0008] Electrostatic paint charging can be designed as an external charging system. The electrostatic charging of the spray jet is then achieved by a separate external charging electrode, which is at high-voltage potential during operation and therefore charges the spray jet of the applied paint accordingly. In contrast to an alternative contact charging (direct charging), with external charging there is no physical contact between the external charging electrode on the one hand and the bell cup or the atomizer shaft of the rotary atomizer on the other. However, during operation, electrical discharges occur between the external charging electrode and the bell cup, so that the bell cup and the atomizer shaft can also assume a high-voltage potential, which is undesirable.In the worst case, with an increasing high-voltage potential of the atomizer shaft, voltage flashovers across a bearing gap in an aerostatic or aerodynamic bearing of the atomizer shaft can occur, causing a so-called high-voltage burn-up and damaging the atomizer shaft or the bearing.

[0009] To prevent such a charging of the atomizer shaft to high-voltage potential, EP 0 796 663 A2 discloses a discharge device that discharges the high-voltage potential from the atomizer shaft of the rotary atomizer and thus electrically grounds the atomizer shaft. This known discharge device consists of an aluminum ring that internally supports carbon fiber bundles that protrude radially inward from the aluminum ring and, during operation, touch the outer surface of the atomizer shaft, thereby establishing electrical contact. The aluminum ring is electrically grounded, so that any high-voltage potential of the atomizer shaft is discharged via the discharge device. However, this known discharge device is associated with various disadvantages, which are briefly described below.

[0010] A disadvantage of the known discharge device is that the carbon fiber bundles rub against the fast-rotating atomizer shaft, which can get into the exhaust air and form residues.

[0011] In addition, the service life of the known discharge device is shorter than the service life of the rotary atomizer, so that the discharge device must be replaced more frequently during operation.

[0012] A further disadvantage is that the discharge device in the rotary atomizer is located at the proximal end of the atomizer shaft, i.e., relatively far from the bell cup and, in particular, from the bearing in the rotary atomizer. Because of this large distance between the discharge device and the bearing, disruptive voltage surges can still occur in the bearing, resulting in undesirable high-voltage burn-off.

[0013] Furthermore, the production of the known discharge device is cost-intensive due to the hybrid construction of aluminum for the aluminum ring and carbon fiber for the carbon fiber bundles.

[0014] Finally, the installation of the well-known discharge device using screws is also costly and time-consuming.

[0015] Similar discharge devices are also known from DE 20 2014 105 015 Ul and DE 10 2020 007 030 Al.

[0016] Finally, regarding the general technical background of the invention, reference should also be made to US 5

[0017] 474 236 A.

[0018] The invention is therefore based on the object of creating a correspondingly improved discharge device which makes it possible to discharge a high-voltage potential from a rotor (e.g. atomizer shaft).

[0019] This object is achieved by a discharge device according to the invention according to the main claim.

[0020] The discharge device according to the invention is primarily intended to discharge a high-voltage potential from an atomizer shaft of a rotary atomizer that has an electrostatic coating agent charge. However, the discharge device according to the invention is not limited to use with a rotary atomizer. Rather, the discharge device according to the invention can be used generally to discharge a high-voltage potential from a rotor.

[0021] In accordance with the known diverting device described at the outset, the diverting device according to the invention also initially has a diverting ring which surrounds the rotor in a ring-like manner.

[0022] Furthermore, the discharge device according to the invention, in accordance with the known discharge device described at the outset, also has at least one electrically conductive contact element which is arranged on the discharge ring and touches the rotor in order to discharge the high-voltage potential from the rotor.

[0023] The invention is distinguished from the known discharge device described above in that the discharge ring, together with the at least one contact element, is formed as a single, integral component. In contrast to the known discharge device described above, the discharge ring and the contact elements are therefore not separate components that are then connected to one another. Rather, the contact elements are formed as a single piece onto the discharge ring, so that the discharge ring forms an integral component.

[0024] In a preferred embodiment of the invention, the integral component consists of a non-metallic and electrically conductive material. This also distinguishes the invention from the known discharge device described above with an aluminum discharge ring. Preferably, the integral component consists of an electrically conductive plastic with a volume resistance of less than 10 kΩ-m, e.g., polyphenylene sulfide (PPS).

[0025] In the preferred embodiment of the invention, the integral component has a plurality of contact elements distributed over the circumference of the discharge ring. For example, the integral component can have more than two, three, or four contact elements, which preferably protrude radially inward from the discharge ring. The individual contact elements are preferably distributed equidistantly over the circumference of the discharge ring.

[0026] It should also be mentioned that the individual contact elements are preferably designed to each establish one or more point contacts with the rotor. Such point contacts with the rotor are advantageous for a variety of reasons compared to surface contact. Firstly, surface contact between the contact elements on the one hand and the outer surface of the rotary atomizer on the other hand can create a disruptive air boundary layer that causes electrical insulation, which prevents the high-voltage potential from being dissipated from the atomizer shaft. Secondly, point contacts have a lower braking effect on the atomizer shaft than surface contact, so that the dissipation device according to the invention generates lower mechanical power loss.

[0027] In the preferred embodiment of the invention, the individual contact elements are each radial webs that protrude radially inward from the discharge ring. The radially inner end faces of the radial webs are concave and have a specific radius of curvature that is smaller than the radius of curvature of the outer surface of the rotor (e.g., atomizer shaft). This ensures that the contact between the radially inner end faces of the radial webs, on the one hand, and the outer surface of the rotor (e.g., atomizer shaft), on the other hand, is not flat, but forms point contacts, which are advantageous, as explained above.

[0028] It should also be noted that the diverter ring can have at least one indentation on the outside to achieve elastic compliance of the diverter ring, allowing the diverter ring to rebound in the radial direction. Preferably, several such indentations are arranged on the outside, distributed over the circumference of the diverter ring. For example, three, four, or five such indentations can be provided on the diverter ring. The indentations are preferably arranged equidistantly around the circumference of the diverter ring.

[0029] It should be noted that the indentations on the outside of the discharge ring are preferably arranged in the same angular position as the contact elements, so that one of the indentations is located on the outside of the discharge ring and one of the contact elements is located on the inside in the same angular position.

[0030] With regard to the indentations, it should also be mentioned that they each have a certain depth in the radial direction, whereby this depth of the indentations is preferably at least 20%, 30%, 40%, 50%, 60%, 70%, 80% or even at least 90% of the radial thickness of the diverter ring next to the indentations.

[0031] In general, it should be noted that the integral component is preferably made of a significantly softer material than the rotor (e.g., the atomizer shaft) to minimize wear on the rotor. For example, the integral component can be made of plastic, preferably an electrically conductive plastic. Therefore, the integral component is preferably made of a relatively soft material with a Shore D value of less than 90, 80, 70, 60, 50, 40, 30, 20, or 10 to minimize wear on the rotor.

[0032] Furthermore, it should be mentioned that the integral component with the rotor preferably forms a material pairing with a friction coefficient which, in the case of sliding friction, is less than 0.5, 0.3, 0.2, 0.1 or 0.05, so that the discharge device exerts only a low braking torque on the atomizer shaft during operation.

[0033] It has already been mentioned above that the material of the integral component is electrically conductive in order to be able to dissipate the high-voltage potential from the rotor (e.g., atomizer shaft). Therefore, the material of the integral component preferably has an electrical conductivity of at least 10 12 S-crrT 1 , IO 10 S-cm" 1 , 10' 8 S-cm" 1 , 10' 6 S-cm" 1 , 10' 4 S-cm" 1 , 10' 2 S-cm" 1 , 1 S-cm" 1 , 10 S-cm" 1 , 100 S-cm" 1 or 100 S-cm" 1 on.

[0034] In addition, the integral component should be made of a material with low abrasion to minimize contamination of the components to be painted by material abrasion from the integral component. The material of the integral component should therefore have an abrasion value of less than 500 mm according to DIN 53516. 3 , 300 mm 3 , 200 mm 3 , 100 mm 3 , 50 mm 3 or 20 mm 3 have.

[0035] In the preferred embodiment of the invention, the integral component consists of a material that combines the following properties mentioned above, which leads to optimal suitability for the intended use according to the invention:

[0036] • The material of the integral component is softer than the atomizer shaft to minimize wear on the atomizer shaft.

[0037] • The material of the integral component is electrically conductive in order to dissipate the high voltage potential from the atomizer shaft.

[0038] • The material of the integral component serves as a wearing part.

[0039] • The material of the integral component has a low coefficient of friction when sliding with the atomizer shaft, so that the contact between the integral component and the atomizer shaft only leads to a low mechanical power loss.

[0040] In the preferred embodiment of the invention, several axial webs protrude from the diverter ring at the peripheral edge of the diverter ring, with the axial webs preferably being distributed equidistantly around the circumference. An axial web is preferably arranged between each pair of contact elements. The axial webs and the contact elements thus preferably alternate around the circumference of the diverter ring. These axial webs serve as spacers to allow for flexible spacing in the event of changes.

[0041] In one variant of the invention, the contact elements are elastic spring tongues that are molded onto the inside of the deflector ring and press resiliently against the outer surface of the rotor (e.g., atomizer shaft). The individual spring tongues are preferably elastically deflectable in a plane that is aligned at right angles to the rotational axis of the rotor. An advantage of this variant of the invention is the fact that the deflector ring is relatively insensitive to diameter deviations of the outer surface of the rotor, since the individual spring tongues can compensate for such diameter deviations by radial rebound. In this way, diameter deviations of the rotor (e.g., atomizer shaft) of more than 0.1 mm, 0.2 mm, 0.5 mm, 1 mm, 2 mm, or 3 mm can be compensated.The individual spring tongues are preferably formed on the inside of the diverter ring and protrude from the diverter ring in the circumferential direction either in the direction of rotation of the rotor or against the direction of rotation of the rotor.

[0042] In this variant of the invention, the spring tongues projecting circumferentially from the discharge ring form a notch with the rest of the discharge ring, so that corresponding notch stresses can occur in this notch. To reduce these disruptive notch stresses, the individual spring tongues preferably merge into the discharge ring via a fillet with a radius of at least 0.1 mm, 0.2 mm, 0.5 mm, 1 mm, 2 mm, or 3 mm.

[0043] The above-mentioned spring tongues preferably have a concavely curved contact surface with a specific radius of curvature on the inside, wherein the radius of curvature of the contact surface of the spring tongues is preferably smaller than the radius of curvature of the outer surface of the rotor in the contact area, so that the inner contact surfaces of the spring tongues do not form a flat contact with the outer surface of the rotor, but rather point contacts.

[0044] This variant of the invention with the contact elements as spring tongues also offers the advantage that the diverter ring can be used in different types of turbines of rotary atomizers.

[0045] The discharge device according to the invention was described above as a single component. However, the invention also claims protection for a rotary atomizer with such a discharge device for discharging a high-voltage potential from the atomizer shaft of the rotary atomizer.

[0046] In a preferred embodiment of the invention, the electrostatic coating agent charging of the rotary atomizer comprises an external charging system with an external charging electrode that is separate from the atomizer shaft, so that the atomizer shaft is electrostatically charged to the high-voltage potential by an electrical discharge from the external charging electrode to the atomizer shaft. This type of electrostatic coating agent charging by means of an external charging system is to be distinguished from direct charging (contact charging), in which the paint-carrying components of the rotary atomizer themselves are charged to a high-voltage potential.During operation of such a rotary atomizer with external charging, the electrical discharge from the external charging electrode acts on the atomizer shaft at an impact point at the distal end of the atomizer shaft, for example, on a bell cup mounted at the distal end of the atomizer shaft. The integral component according to the invention for discharging the high-voltage potential from the atomizer shaft is preferably located near the impact point of the electrical discharge from the external charging electrode, i.e., at the distal end of the atomizer shaft. Therefore, the axial distance between the integral component, on the one hand, and the distal end of the atomizer shaft, on the other hand, is preferably shorter than 10 cm, 7 cm, 5 cm, 3 cm, or even shorter than 2 cm.

[0047] The rotary atomizer according to the invention typically has a bearing for rotatably supporting the atomizer shaft. For example, this can be an aerodynamic bearing or an aerostatic bearing. The integral component according to the invention for dissipating a high-voltage potential from the atomizer shaft is preferably located in the axial direction between the bearing on the one hand and the distal end of the atomizer shaft on the other, in order to reliably prevent high-voltage burn-off in the bearing.

[0048] In general, it should be mentioned that the integral component in the rotary atomizer according to the invention is preferably electrically grounded or at a potential close to earth in order to be able to divert the high-voltage potential from the atomizer shaft.

[0049] The above-mentioned electrostatic coating agent charging may have a charging voltage of at least 10 kV, 20 kV, 50 kV or 100 kV.

[0050] It should also be noted that the integral component preferably touches the outer surface of the atomizer shaft. However, within the scope of the invention, it is also fundamentally possible for the integral component to touch the atomizer shaft at other points in order to dissipate the high-voltage potential from the atomizer shaft.

[0051] In accordance with the state of the art, the atomizer shaft may have a thread at its distal end to enable the spray body to be screwed onto the atomizer shaft.

[0052] Finally, the invention also claims protection for the novel use of the inventive discharge device for discharging a high-voltage potential from an atomizer shaft of a rotary atomizer with an electrostatic coating agent charge. Other advantageous developments of the invention are characterized in the subclaims or are explained in more detail below together with the description of the preferred embodiment of the invention with reference to the figures.

[0053] Brief description of the drawings

[0054] Figure 1 shows a longitudinal section through a rotary atomizer according to the invention with a discharge device according to the invention for discharging a high-voltage potential from the atomizer shaft of the rotary atomizer.

[0055] Figure 2 shows a cross-sectional view through the rotary atomizer according to Figure 1 along the section line AA in Figure 1.

[0056] Figure 3 shows the discharge device according to the invention as a single component.

[0057] Figure 4 shows a perspective view of the discharge device according to the invention as a single component.

[0058] Figures 5A-5C show various views of an alternative embodiment of a diverter device according to the invention with several spring tongues that are distributed over the circumference of the diverter ring.

[0059] Figure 6 shows a cross-sectional view through a rotary atomizer with a discharge device according to the invention according to Figures 5A-5C on a non-stepped atomizer shaft.

[0060] Figure 7 shows a cross-sectional view through a rotary atomizer with a discharge device according to the invention according to Figures 5A-5C on a stepped atomizer shaft.

[0061] Detailed description of the drawings

[0062] The following describes the exemplary embodiment of a rotary atomizer 1 according to the invention, which is illustrated in the drawings and has an external electrostatic charge, as indicated by the high-voltage symbol. The rotary atomizer 1 according to the invention is largely conventionally constructed, as is known from the prior art, and comprises an atomizer shaft 2, which has a mounting interface at its distal end 3 for mounting a bell cup (the bell cup is not shown). For example, the mounting interface can be a thread, so that the bell cup can be screwed onto the distal end 3 of the atomizer shaft 2.

[0063] During operation, the atomizer shaft 2 rotates about a rotation axis 4 and can be driven by a compressed air turbine, which, however, is not shown for the sake of simplicity.

[0064] In the rotary atomizer 1, the atomizer shaft 2 is rotatably mounted in a bearing 5, although the bearing 5 is only partially shown here. For example, the bearing 5 can be an aerodynamic or aerostatic bearing.

[0065] Furthermore, the drawing shows that the rotary atomizer 1 has a housing 6 which is closed at its distal end by a housing cover 7, wherein the atomizer shaft 2 projects through an opening in the housing cover 7 in the axial direction.

[0066] Located radially between the outer housing cover 7 and the inner atomizer shaft 2 is a discharge device 8 according to the invention, which is manufactured as an integral component from an electrically conductive plastic. This means that the discharge device 8 is formed in one piece and has an annular, circumferential discharge ring 9 and five radially inwardly projecting contact elements 10, as can be seen in particular in Figures 2-4.

[0067] The discharge device 8 is located at a relatively short axial distance a from the distal end 3 of the atomizer shaft 2. This is advantageous because the point of action of the electrical discharges from the external charging electrode (shown only symbolically as a high-voltage symbol) is located at the distal end 3 of the atomizer shaft 2, so the discharge device 8 should be located as close as possible to this point of action. The axial distance a between the distal end 3 of the atomizer shaft 2 and the discharge device is therefore a<5 cm.

[0068] Furthermore, it should be noted that the discharge device 8 is located axially between the distal end 3 of the atomizer shaft 2 and the bearing 5. This ensures that any high-voltage potential of the atomizer shaft 2 is discharged by the discharge device 8 before it can reach the bearing 5, which could, in the worst case, lead to high-voltage burn-off there.

[0069] The contact elements 10 protrude radially inwards from the discharge ring 9 as radial webs and, during operation, touch the outer surface of the atomizer shaft 2 in order to discharge the high-voltage potential from the atomizer shaft 2, which is why the discharge device 8 itself is electrically earthed, as indicated in the drawing by the earth symbol.

[0070] It should be noted here that the individual contact elements 10 do not make surface contact with the outer surface of the atomizer shaft 2. Rather, the contact elements 10 each form two point contacts 11, 12 with the outer surface of the atomizer shaft 2. The surface contact between the radially inner end face of the contact elements 10 on the one hand and the outer surface of the atomizer shaft 2 on the other hand is prevented by the fact that the radially inner end face of the contact elements 10 is concavely shaped with a radius of curvature that is smaller than the radius of curvature of the outer surface of the atomizer shaft 2. This prevents surface contact between the radially inner end faces of the contact elements 10 on the one hand and the outer surface of the atomizer shaft 2 on the other.The above-mentioned point contacts between the outer surface of the atomizer shaft 2 on the one hand and the contact elements 10 on the other hand are advantageous for various reasons, as will be explained below.

[0071] On the one hand, the point contacts 11, 12 lead to a lower friction force compared to flat contacts and thus also to a lower mechanical power loss caused by the discharge device 8.

[0072] On the other hand, in the case of surface contact, a disturbing air boundary layer can arise which has an electrically insulating effect and prevents the high voltage from being dissipated from the atomizer shaft 2.

[0073] Furthermore, it should be mentioned that the diverter ring 9 has five indentations 13 on its outer side, which enable elastic compliance of the diverter ring 9, so that the diverter ring 9 can rebound in the radial direction.

[0074] The indentations 13 are each arranged in the same angular position as the radially inwardly projecting contact elements 10. The indentations 13 each have a radial depth d which is greater than the radial thickness b of the discharge ring 9 between the adjacent en 13.

[0075] Figure 4 also shows that five axial ribs 14 protrude axially from the diverter ring 9. The axial ribs 14 serve as spacers to maintain a flexible spacing in the event of changes.

[0076] The following describes the embodiment of a discharge device 8 according to the invention, which is illustrated in Figures 5A-5C. This embodiment partially corresponds to the embodiment of the invention described above, so that, to avoid repetition, reference is made to the above description, the same reference numerals being used for corresponding details.

[0077] A special feature of this embodiment is that the contact elements 10 are designed as spring tongues which are formed on the inside of the diverter ring 9 and protrude from the diverter ring 9 in the circumferential direction, specifically in this embodiment in the direction of rotation of the atomizer shaft 2.

[0078] The individual contact elements 10 merge into the discharge ring 9 via a rounded portion 15, whereby the rounded portion 15 is intended to reduce notch stresses at the transition between the contact elements 10 shaped as spring tongues and the discharge ring 9.

[0079] It should also be noted that the contact elements 10, designed as spring tongues, each have a concavely curved contact surface on the inside, which has a smaller radius of curvature than the outer surface of the atomizer shaft 2 in the contact area. This is advantageous because it does not create a flat contact with the outer surface of the atomizer shaft 2, but rather point contacts 11, 12.

[0080] Furthermore, it should be mentioned that the contact elements 10 designed as spring tongues can rebound in the radial direction and can thus compensate for diameter deviations of the atomizer shaft 2.

[0081] Figure 6 shows the use of the discharge device 8 according to Figures 5A-5C on a non-stepped atomizer shaft 2, whereas Figure 7 shows the use of the discharge device 8 according to Figures 5A-5C on a stepped atomizer shaft 2.

[0082] The invention is not limited to the preferred embodiment described above. Rather, a multitude of variants and modifications are possible, which also utilize the inventive concept and therefore fall within the scope of protection. In particular, the invention also claims protection for the subject matter and features of the subclaims, independently of the respective claims referred to, and in particular even without the features of the main claim. The invention thus encompasses various aspects of the invention that enjoy independent protection.

[0083] Advantages of

[0084] The invention offers various advantages, which are briefly explained below:

[0085] • Firstly, the invention enables a compact design of the discharge device.

[0086] • Furthermore, within the scope of the invention there is the possibility that the discharge device is made of an electrically conductive plastic.

[0087] • Due to the abrasion resistance of the discharge device according to the invention, only minimal abrasion occurs.

[0088] • The discharge device according to the invention can be implemented in a wide variety of geometries and sizes.

[0089] • Due to the point contact between the discharge device and the atomizer shaft, only low friction occurs, so that only a correspondingly low mechanical power loss is generated.

[0090] • The indentations on the outside of the deflection ring allow radial rebound of the deflection ring and adaptation to the respective wave movement of the atomizer shaft.

[0091] • Due to the manufacture of the discharge device according to the invention as an integral component made from one piece, the manufacturing costs are lower than in the prior art.

[0092] • In contrast to the carbon fiber bundles in the prior art, the inner diameter of the discharge device according to the invention can be manufactured more precisely.

[0093] • Due to the more precise manufacturing possibilities, no running-in phase of the discharge device according to the invention is required.

[0094] 1 rotary atomizer

[0095] 2 atomizer shaft of the rotary atomizer

[0096] 3 Distal end of the atomizer shaft

[0097] 4 Rotation axis of the atomizer shaft

[0098] 5 bearings for the rotating mounting of the atomizer shaft

[0099] 6 Housing of the rotary atomizer

[0100] 7 Housing cover of the rotary atomizer

[0101] 8 Discharge device

[0102] 9 Discharge ring

[0103] 10 contact elements on the discharge ring

[0104] 11, 12 Point contacts between the deflection ring and the atomizer shaft

[0105] 13 indentations on the outside of the deflection ring to enable radial rebound

[0106] 14 axial webs on the diverter ring

[0107] 15 Fillet between spring tongues and deflection ring a Axial distance between the deflection ring and the distal end of the atomizer shaft b Thickness of the deflection ring in radial direction d Depth of the indentations in the deflection ring in radial direction

Claims

CLAIMS 1. Discharge device (8) for discharging a high-voltage potential from a rotor (2), in particular from an atomizer shaft (2) of a rotary atomizer (1) with an electrostatic coating agent charge, with a) a discharge ring (9) which surrounds the rotor (2) in a ring shape, and b) at least one electrically conductive contact element (10) which is arranged on the discharge ring (9) and touches the rotor (2) in order to dissipate the high-voltage potential from the rotor (2), characterized in that c) the discharge ring (9) together with the at least one contact element (10) are formed in one piece as an integral component (8).

2. Discharge device (8) according to claim 1, characterized in that a) the integral component (8) consists of a non-metallic and electrically conductive material, and / or b) the integral component (8) consists of an electrically conductive plastic.

3. Discharge device (8) according to one of the preceding claims, characterized in that a) the integral component (8) has a plurality of contact elements (10) which are arranged distributed over the circumference of the discharge ring (9), b) the number of contact elements (10) is preferably greater than two, three or four, c) the contact elements (10) are preferably arranged equidistantly distributed over the circumference of the discharge ring (9), d) the individual contact elements (10) are preferably designed to each establish one or more point contacts (11, 12) with the rotor (2) and thereby, in contrast to a surface contact, to prevent the formation of a separating air boundary layer and to keep the braking torque of the discharge device (8) low, e) the individual contact elements (10) preferably protrude radially inwards from the discharge ring (9).

4. Discharge device (8) according to one of the preceding claims, characterized in that a) the individual contact elements (10) are each radial webs which extend from the discharge ring (9) protrude radially inwards, b) that the radial webs (10) each have a radially inner end face which is concavely shaped with a certain radius of curvature, and c) that the radius of curvature of the inner end faces of the radial webs (10) is smaller than the radius of curvature of the outer surface of the rotor (2), so that the inner end faces of the radial webs (10) do not form a surface contact with the outer surface of the rotor (2), but rather point contacts.

5. Discharge device (8) according to one of the preceding claims, characterized in that a) the discharge ring (9) has at least one indentation (13) on the outside in order to achieve elastic compliance of the discharge ring (9) so that the discharge ring (9) can rebound in the radial direction, b) preferably several of the indentations (13) are arranged distributed externally over the circumference of the discharge ring (9), in particular at least three, four or five indentations (13), c) the indentations (13) on the outside of the discharge ring (9) are preferably arranged equidistantly over the circumference of the discharge ring (9), d) the indentations (13) on the outside of the discharge ring (9) are preferably arranged in the same angular position as the contact elements (10), so that on the discharge ring (9) one of the indentations (13) is located on the outside and one of the contact elements (10) is located on the inside, in the same angular position,e) that the indentations (13) on the outside of the diverter ring (9) preferably each have a depth (d) in the radial direction which is at least 20%, 30%, 40%, 50%, 60%, 70%, 80% or 90% of the radial thickness (b) of the diverter ring (9) next to the indentations (13).

6. Discharge device (8) according to one of the preceding claims, characterized in that a) the integral component (8) consists of a substantially softer material than the rotor (2) in order to minimize wear on the rotor (2), and / or b) the integral component (8) is preferably made of plastic, and / or c) that the integral component (8) forms a material pairing with the rotor (2) with a coefficient of friction which, under sliding friction, is less than 0.5, 0.3, 0.2, 0.1 or 0.05, and / or d) that the integral component (8) consists of a material with a Shore hardness of less than 90, 80, 70, 60, 50, 40, 30, 20 or 10 Shore-D in order to minimize wear on the rotor (2), and / or e) that the integral component (8) consists of a material with an electrical conductivity of at least 10'^ S-cm" 1 , IO 10 S-cm" 1 , 10' 8 S-cm" 1 , 10' 6 S-cm" 1 , 10' 4 S-cm" 1 , 10' 2 S-cm" 1 , 1 S-cm" 1 , 10 S-cm" 1 , 100 S-cm" 1 , 100 S-cm" 1 and / or f) that the integral component (8) is made of an abrasion-resistant material with an abrasion value according to DIN 53516 of less than 500 mm 3 , 300 mm 3 , 200 mm 3 , 100 mm 3, 50 mm 3 or 20 mm 3 consists.

7. Discharge device (8) according to one of the preceding claims, characterized in that a) a plurality of axial webs (14) project in the axial direction from the discharge ring (9) at the circumferential edge in order to serve as spacers, b) that the axial webs (14) are distributed equidistantly over the circumference, c) that the axial webs (14) are arranged in the circumferential direction preferably between the contact elements (10) and / or between the indentations (13).

8. Diversion device (8) according to one of the preceding claims, characterized in that a) the contact elements (10) are elastic spring tongues which are formed on the inside of the diversion ring (9) and resiliently press against the outer surface of the rotor (2), and / or b) the contact elements (10) designed as spring tongues are elastically deflectable in a plane which is aligned at right angles to the axis of rotation of the rotor (2), and / or c) the contact elements (10) designed as spring tongues protrude from the diversion ring (9) in the circumferential direction in the direction of rotation or counter to the direction of rotation of the rotor (2), and / or d) the diversion ring (9) allows diameter deviations of the outer surface of the rotor (2) of at least 0.1 mm, 0.2 mm, 0.5 mm, 1 mm, 2 mm or 3 mm, and / or e) the contact elements (10) designed as spring tongues each have a Rounding (15) with a radius of at least 1 mm, 2 mm or 3 mm is formed on the diverter ring (9).

9. Diversion device (8) according to claim 8, characterized in that a) the contact elements (10) designed as spring tongues for contacting the outer surface of the rotor (2) have a concavely curved contact surface with a certain radius of curvature, and b) that the radius of curvature of the contact surface of the contact elements (10) designed as spring tongues is preferably smaller than the radius of curvature of the outer surface of the rotor (2), so that the inner contact surfaces do not form a flat contact with the outer surface of the rotor (2), but rather point contacts (11, 12).

10. Rotary atomizer (1) for coating a component, in particular a motor vehicle body component, with a coating agent, in particular with a paint, with a) a rotatably mounted atomizer shaft (2) for rotating a spray body, in particular a bell cup, b) an electrostatic coating agent charger for electrostatically charging the applied coating agent, and c) a discharge device (8) for discharging a high-voltage potential resulting from the electrostatic coating agent charge from the atomizer shaft (2), characterized in that d) that the discharge device (8) is designed according to one of the preceding claims.

11. Rotary atomizer (1) according to claim 10, characterized in that the electrostatic coating agent charging has an external charging with an external charging electrode which is separate from the atomizer shaft (2), so that the atomizer shaft (2) is electrostatically charged to the high-voltage potential by an electrical discharge from the external charging electrode to the atomizer shaft (2).

12. Rotary atomizer (1) according to claim 11, characterized in that a) the electrical discharge from the external charging electrode acts on the atomizer shaft (2) at an action point at the distal end (3) of the atomizer shaft (2), in particular on a bell cup which is mounted on the atomizer shaft (2), and b) that the integral component (8) surrounds the atomizer shaft (2) in a ring shape at the distal end (3) of the atomizer shaft (2) near the action point of the electrical discharge, in particular with an axial distance (a) from the distal end (3) of the atomizer shaft (2) of less than 10 cm, 7 cm, 5 cm, 3 cm or 2 cm.

13. Rotary atomizer (1) according to one of claims 10 to 12, characterized in that a) the atomizer shaft (2) is rotatably mounted in a bearing (5), in particular in an aerodynamic bearing (5) or in an aerostatic bearing (5), and b) the integral component (8) is arranged in the axial direction between the bearing (5) and the distal end of the atomizer shaft (2) in order to avoid high-voltage burn-off in the bearing (5).

14. Rotary atomizer (1) according to one of claims 10 to 13, characterized in that a) the integral component (8) is electrically earthed or has a potential close to earth, and / or b) the electrostatic coating agent charge has a charging voltage of at least 10 kV, 20 kV, 50 kV or 100 kV, and / or c) the integral component (8) touches the outer surface of the atomizer shaft (2), and / or d) the atomizer shaft (2) has a thread at its distal end in order to be able to screw the spray body onto the atomizer shaft (2).

15. Use of a discharge device (8) according to one of claims 1 to 9 for discharging a high-voltage potential from an atomizer shaft (2) of a rotary atomizer (1) with an electrostatic coating agent charge.

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