Discharge device and rotary atomizer equipped with the same

Abstract

This invention relates to a discharge device (8) for extracting a high-voltage potential from a rotor (2), particularly from the atomizer shaft (2) of a rotary atomizer (1) equipped with an electrostatic coating charging system. The discharge device of this invention comprises a discharge ring (9) annularly surrounding the rotor (2), and at least one conductive contact element (10) arranged on the discharge ring (9) and in contact with the rotor (2) to extract the high-voltage potential from the rotor (2). A key design feature of this invention is that the discharge ring (9) and the at least one contact element (10) are integrally formed as a single component (8).

Description

Technical Field

[0001] This invention relates to a discharge device for extracting a high-voltage potential from the rotor, particularly from the atomizer shaft of a rotary atomizer equipped with an electrostatic coating charging system. The invention also relates to a rotary atomizer equipped with this discharge device. Background Technology

[0002] In modern painting systems used for painting vehicle body parts, rotary atomizers are typically used as the coating device. To improve coating efficiency or avoid interfering overspray, existing technologies also employ electrostatic paint charging systems. These systems charge the paint mist to a high voltage potential while keeping the vehicle body parts to be painted electrically grounded, thus ensuring that the paint is almost completely deposited on the vehicle body parts, resulting in only a very small amount of overspray.

[0003] The electrostatic coating charging system can be designed as an external charging system. In this case, the electrostatic charging of the coating mist is achieved by a separate external charging electrode, which operates at a high voltage potential during operation, thereby charging the coating mist accordingly. Unlike the alternative contact charging (direct charging), there is no contact between the external charging electrode and the bell cup or atomizer shaft of the rotating atomizer. However, during operation, a discharge phenomenon occurs between the external charging electrode and the bell cup, causing the bell cup and atomizer shaft to also carry a high voltage potential, which is undesirable. In the worst case, the high voltage potential of the atomizer shaft continuously increases, leading to voltage flashover across the bearing clearance in the atomizer shaft's hydrostatic or hydrodynamic bearings, resulting in so-called high-voltage ablation and damage to the atomizer shaft or bearings.

[0004] To prevent the atomizer shaft from being charged to a high voltage potential, EP0796663A2 discloses a discharge device that can discharge the high voltage potential on the atomizer shaft of a rotating atomizer, thereby electrically grounding the atomizer shaft. This existing discharge device includes an aluminum ring with a carbon fiber bundle disposed inside the ring. The carbon fiber bundle extends radially inward from the aluminum ring and contacts the outer surface of the atomizer shaft during operation, thus achieving electrical connection. The aluminum ring remains electrically grounded, so any high voltage potential on the atomizer shaft can be discharged through this discharge device. However, this existing discharge device has several drawbacks, which will be briefly described below.

[0005] One drawback of this existing discharge device is that the carbon fiber bundles will wear down on the high-speed rotating atomizer shaft, and the resulting debris will enter the exhaust gas and form residues.

[0006] Furthermore, the lifespan of this existing discharge device is shorter than that of the rotary atomizer, thus requiring more frequent replacements during operation.

[0007] Another drawback is that the discharge device in the rotary atomizer is located near the atomizer shaft, which is far from the bell cup, and particularly far from the bearing in the rotary atomizer. Due to the large distance between the discharge device and the bearing, interfering voltage flashover may still occur in the bearing, thereby causing the aforementioned unfavorable high-voltage erosion.

[0008] Furthermore, the existing discharge device uses aluminum for the aluminum ring and carbon fiber for the carbon fiber bundle, resulting in a high manufacturing cost due to this hybrid structure.

[0009] Finally, installing the existing discharge device using screws is also time-consuming and labor-intensive.

[0010] Similar discharge devices are also disclosed in DE202014105015U1 and DE102020007030A1.

[0011] Finally, for the overall technical background of the present invention, please refer to US5474236A. Summary of the Invention

[0012] Therefore, the objective of this invention is to provide a correspondingly improved discharge device capable of extracting high voltage potential from a rotor (e.g., an atomizer shaft).

[0013] The objective of this invention is achieved through the discharge device described in the independent claim.

[0014] The discharge device described in this invention was originally intended to extract the high voltage potential on the atomizer shaft of a rotary atomizer equipped with an electrostatic coating charging system. However, the application of the discharge device described in this invention is not limited to rotary atomizers; on the contrary, the discharge device described in this invention can be widely used in scenarios where high voltage potential is extracted from various types of rotors.

[0015] Similar to the existing discharge devices described above, the discharge device of the present invention also includes a discharge ring that surrounds the rotor in an annular shape.

[0016] In addition, similar to the existing discharge devices described at the beginning, the discharge device of the present invention also includes at least one conductive contact element arranged on the discharge ring and in contact with the rotor to extract the high voltage potential from the rotor.

[0017] The difference between this invention and the existing discharge device described at the beginning is that the discharge ring and at least one contact element are integrally formed as a single component. Therefore, unlike the existing discharge device described at the beginning, the discharge ring and the contact element are not independent components connected to each other, but rather the contact element is integrally formed on the discharge ring, making the discharge ring a single component.

[0018] In a preferred embodiment of the invention, the integral component is made of a non-metallic and conductive material, which is another difference between the present invention and the existing discharge device equipped with an aluminum discharge ring described at the outset. Preferably, the integral component has a contact resistance of less than 10kΩ. m is made of conductive plastic, such as polyphenylene sulfide (PPS).

[0019] In a preferred embodiment of the invention, the integral component includes a plurality of the aforementioned contact elements arranged along the periphery of the discharge ring. For example, the integral component may have more than two, three, or four contact elements, which preferably extend radially inward from the discharge ring. The contact elements are preferably arranged equidistantly along the periphery of the discharge ring.

[0020] It should also be noted that each contact element is preferably designed to form one or more point contacts with the rotor. Forming such point contacts with the rotor has several advantages over surface contacts. On the one hand, if a surface contact is formed between the contact element and the outer surface of the rotating atomizer, an interfering air boundary layer with electrical insulation properties is generated, hindering the discharge of the high voltage potential on the atomizer shaft. On the other hand, compared to surface contacts, point contacts exert less braking effect on the atomizer shaft, thus resulting in lower mechanical power loss in the discharge device described in this invention.

[0021] In a preferred embodiment of the invention, each contact element is a radially protruding portion extending radially inward from the discharge ring. The radially inner end face of the radially protruding portion is concave and has a specific radius of curvature smaller than the radius of curvature of the outer surface of the rotor (e.g., the atomizer shaft). This design ensures that the radially inner end face of the radially protruding portion does not form a surface contact with the outer surface of the rotor (e.g., the atomizer shaft), but rather forms a favorable point contact as described above.

[0022] It should also be noted that at least one notch may be provided on the outer side of the discharge ring to achieve elastic compliance, allowing the discharge ring to deflect radially. Preferably, multiple notches are arranged along the periphery of the discharge ring on its outer side; for example, three, four, or five notches may be provided on the discharge ring. The notches are preferably arranged at equal intervals along the periphery of the discharge ring.

[0023] It should be noted that the notch on the outer side of the discharge ring is preferably at the same angular position as the contact element, so that at the same angular position, one of the notches is provided on the outer side of the discharge ring and one of the contact elements is provided on the inner side.

[0024] Regarding the notches, it should also be noted that each notch has a certain radial depth, which is preferably at least 20%, 30%, 40%, 50%, 60%, 70%, 80%, or even at least 90% of the radial thickness of the discharge ring next to the notch.

[0025] In general, the one-piece component is preferably made of a material much softer than the rotor (e.g., the atomizer shaft) to minimize rotor wear. For example, the one-piece component can be made of plastic, preferably conductive plastic. Therefore, the one-piece component is preferably made of a soft material with a Shore D hardness of less than 90, 80, 70, 60, 50, 40, 30, 20 or 10, thereby minimizing rotor wear.

[0026] It should also be noted that the sliding friction coefficient of the material pair formed by the integral component and the rotor is preferably less than 0.5, 0.3, 0.2, 0.1 or 0.05, so that the braking torque applied to the atomizer shaft by the discharge device during operation is relatively small.

[0027] As mentioned above, the material of the integrated component is conductive to conduct the high voltage potential on the rotor (such as the atomizer shaft). Therefore, the material of the integrated component preferably has a conductivity of at least 10. -12 S . cm -1 10 -10 S . cm -1 10 -8 S . cm -1 10 - 6 S . cm -1 10 -4 S . cm -1 10 -2 S . cm -1 1S . cm -1 10S . cm -1 100S . cm -1 The electrical conductivity.

[0028] Furthermore, the monolithic component should be made of a material with low material abrasion to minimize contamination of the coated parts caused by material abrasion of the monolithic component. Therefore, the abrasion value of the monolithic component material, measured according to DIN 53516, is preferably less than 500 mm. 3 300mm 3 200mm 3 100mm 3 50mm 3 Or 20mm 3 .

[0029] In a preferred embodiment of the present invention, the integral component is made of a material possessing some of the aforementioned characteristics, making it fully suitable for the intended application scenarios described in the present invention. Specific characteristics are as follows: - The material of the one-piece component is softer than that of the atomizer shaft to minimize wear on the atomizer shaft; - The material of the one-piece component is conductive to conduct the high voltage potential on the atomizer shaft; - The material of the one-piece component can be used as a consumable part; - The material of the one-piece component has a low coefficient of sliding friction with the atomizer shaft, so the contact between the one-piece component and the atomizer shaft only produces a small mechanical power loss.

[0030] In a preferred embodiment of the invention, a plurality of axial protrusions extend from the circumferential edge of the discharge ring, and these axial protrusions are preferably distributed equidistantly along the periphery. Preferably, an axial protrusion is arranged between every two contact elements, thus the axial protrusions and contact elements are preferably arranged alternately along the periphery of the discharge ring. These axial protrusions serve as spacers to flexibly maintain the spacing when dimensions change.

[0031] In a variant of the invention, the contact element is an elastic spring formed inside the discharge ring, which elastically presses against the outer surface of the rotor (e.g., an atomizer shaft). Each elastic spring is preferably capable of elastic deflection in a plane perpendicular to the rotor's axis of rotation. An advantage of this variant is that the discharge ring has high tolerance to diameter deviations in the rotor's outer circumferential surface because each elastic spring can compensate for such diameter deviations through radial deflection. In this way, diameter deviations of the rotor (e.g., an atomizer shaft) exceeding 0.1 mm, 0.2 mm, 0.5 mm, 1 mm, 2 mm, or 3 mm can be compensated.

[0032] Each elastic tongue is preferably formed inside the discharge ring and extends out of the discharge ring in the circumferential direction along or against the direction of rotation of the rotor.

[0033] In this variant of the invention, a gap is formed between the elastic tongue extending from the discharge ring in the circumferential direction and the rest of the discharge ring, where a corresponding notch stress may occur. To reduce this interfering notch stress, each elastic tongue preferably transitions to the discharge ring by a rounded transition, the radius of which is at least 0.1 mm, 0.2 mm, 0.5 mm, 1 mm, 2 mm, or 3 mm.

[0034] The inner side of the aforementioned elastic tongue preferably has a concave curved contact surface, which has a specific radius of curvature, and the radius of curvature is preferably smaller than the radius of curvature of the outer surface of the rotor in the contact area. Therefore, the inner contact surface of the elastic tongue and the outer surface of the rotor are not in surface contact, but rather form a point contact.

[0035] The variant of the invention with a spring-loaded contact element has another advantage: the discharge ring can be adapted to different types of rotary atomizer turbines.

[0036] The discharge device described above is a single component, and the present invention also claims protection for a rotary atomizer equipped with the discharge device to extract the high voltage potential on the atomizer shaft of the rotary atomizer.

[0037] In a preferred embodiment of the invention, the electrostatic coating charging system of the rotary atomizer includes an external charging system with an external charging electrode that is separate from the atomizer shaft. Therefore, the atomizer shaft is charged to a high voltage potential by the discharge from the external charging electrode. This electrostatic charging method of the coating achieved through external charging differs from direct charging (contact charging), in which the coating component of the rotary atomizer itself is charged to a high voltage potential.

[0038] During operation of the rotary atomizer equipped with this external charging system, the discharge of the external charging electrode acts on a point of action at the distal end of the atomizer shaft, for example, on the bell-shaped cup mounted at the distal end of the atomizer shaft. The integrated component for deriving the high-voltage potential of the atomizer shaft, as described in this invention, is preferably located near the point of action of the discharge of the external charging electrode, i.e., at the distal end of the atomizer shaft. Therefore, the axial distance between the integrated component and the distal end of the atomizer shaft is preferably less than 10cm, 7cm, 5cm, 3cm, or even less than 2cm.

[0039] The rotary atomizer described in this invention is typically equipped with a bearing for rotatably supporting the atomizer shaft; for example, the bearing may be a pneumatic or hydrostatic bearing. The integrated component for deriving the high-voltage potential of the atomizer shaft, as described in this invention, is preferably arranged axially between the bearing and the distal end of the atomizer shaft to reliably prevent high-voltage ablation within the bearing.

[0040] In general, the integrated component in the rotary atomizer of the present invention is preferably electrically grounded or at near-ground potential in order to conduct the high voltage potential on the atomizer shaft.

[0041] The charging voltage of the electrostatic coating agent charging system is preferably at least 10kV, 20kV, 50kV or 100kV.

[0042] It should also be noted that the one-piece component preferably contacts the outer surface of the atomizer shaft. However, within the scope of this invention, the one-piece component may also contact the atomizer shaft at other locations in principle to conduct the high voltage potential on the atomizer shaft.

[0043] According to existing technology, the distal end of the atomizer shaft can be threaded to allow the spray body to be screwed onto the atomizer shaft.

[0044] Finally, the present invention also claims a novel use of the discharge device described herein, namely, for extracting a high voltage potential on the atomizer shaft of a rotary atomizer equipped with an electrostatic coating charging system.

[0045] Other advantageous embodiments of the invention are defined by the dependent claims, or described in detail below in conjunction with the description of preferred embodiments of the invention and with reference to the accompanying drawings. Attached Figure Description

[0046] Figure 1 This is a longitudinal sectional view of a rotary atomizer equipped with a discharge device according to the present invention, the discharge device being used to extract the high voltage potential on the atomizer shaft of the rotary atomizer. Figure 2 For along Figure 1 AA section line pair Figure 1 A cross-sectional view of the rotary atomizer; Figure 3 This is a schematic diagram of the single-unit structure of the discharge device described in this invention; Figure 4 This is a three-dimensional schematic diagram of the single-unit structure of the discharge device described in this invention; Figures 5A-5C This is a different view of another embodiment of the discharge device described in the present invention, which is equipped with a plurality of elastic tongues along the periphery of the discharge ring; Figure 6 For equipped Figures 5A-5C The diagram shows a cross-sectional view of the rotating atomizer of the discharge device of the present invention on the axis of a non-stepped atomizer. Figure 7 For equipped Figures 5A-5C The diagram shows a cross-sectional view of the rotating atomizer of the discharge device of the present invention on the axis of the stepped atomizer. Detailed Implementation

[0047] The following description, in conjunction with the accompanying drawings, will describe an embodiment of the rotary atomizer 1 of the present invention, which is equipped with an electrostatic external charging system, indicated by a high voltage symbol in the drawings.

[0048] The main structure of the rotary atomizer 1 described in this invention is a conventional design, consistent with existing technology. It includes an atomizer shaft 2, and the distal end 3 of the atomizer shaft 2 has a mounting interface for mounting a bell-shaped cup, which is not shown in the accompanying drawings. For example, the mounting interface can be a threaded structure to screw the bell-shaped cup onto the distal end 3 of the atomizer shaft 2.

[0049] During operation, the atomizer shaft 2 rotates around the rotation axis 4 and can be driven by a compressed air turbine. For the sake of simplicity, the compressed air turbine is not shown in the attached figure.

[0050] In the rotary atomizer 1, the atomizer shaft 2 is rotatably supported by a bearing 5. Only a portion of the structure of the bearing 5 is shown in the attached diagram. For example, the bearing 5 can be a pneumatic hydrodynamic bearing or a pneumatic hydrostatic bearing.

[0051] Furthermore, the accompanying drawings also show that the rotary atomizer 1 includes a housing 6, the distal end of which is closed by a housing end cap 7, and the atomizer shaft 2 extends through an opening in the housing end cap 7 in an axial direction.

[0052] A discharge device 8, as described in this invention, is disposed in the radial gap between the outer housing end cap 7 and the inner atomizer shaft 2. This discharge device is integrally molded from conductive plastic. Specifically, the discharge device 8 is a one-piece structure comprising an annular discharge ring 9 and five contact elements 10 extending radially inward. Figure 2-4 It can be clearly seen in the middle.

[0053] The axial distance 'a' between the discharge device 8 and the distal end 3 of the atomizer shaft 2 is small. This design is advantageous because the discharge point of the external charging electrode (shown schematically only as a high-voltage symbol in the attached figure) is located at the distal end 3 of the atomizer shaft 2. Therefore, the discharge device 8 should be positioned as close as possible to this point of action. Thus, the axial distance 'a' between the distal end 3 of the atomizer shaft 2 and the discharge device is < 5 cm.

[0054] It should also be noted that the discharge device 8 is arranged axially between the distal end 3 of the atomizer shaft 2 and the bearing 5. This design ensures that any high voltage potential on the atomizer shaft 2 is discharged by the discharge device 8 before reaching the bearing 5, thus preventing high voltage ablation caused by the high voltage potential within the bearing 5.

[0055] The contact element 10 is a radial protrusion extending radially inward from the discharge ring 9. During operation, it contacts the outer surface of the atomizer shaft 2 to conduct the high voltage potential on the atomizer shaft 2. Therefore, the discharge device 8 itself is electrically grounded, which is indicated by the grounding symbol in the attached figure.

[0056] It should be noted that the contact elements 10 do not form full-surface contact with the outer surface of the atomizer shaft 2. Instead, each contact element 10 forms two point contacts 11 and 12 with the outer surface of the atomizer shaft 2. The radially inner end face of the contact element 10 is concave, and its radius of curvature is smaller than the radius of curvature of the outer surface of the atomizer shaft 2. This design avoids surface contact between the radially inner end face of the contact element 10 and the outer surface of the atomizer shaft 2. The aforementioned point contacts formed between the outer surface of the atomizer shaft 2 and the contact elements 10 have several advantages, which will be explained below.

[0057] On the one hand, compared with surface contact, point contact 11 and 12 generate less friction, so the mechanical power loss caused by discharge device 8 is also lower; On the other hand, when in contact with the surface, an interfering air boundary layer with electrical insulation effect is generated, which prevents the high voltage potential on the atomizer shaft 2 from being discharged.

[0058] It should also be noted that the discharge ring 9 has five notches 13 on its outer side. These notches allow the discharge ring 9 to bend elastically, thereby enabling the discharge ring 9 to deflect radially.

[0059] The notch 13 and the contact element 10 extending radially inward are at the same angular position.

[0060] The radial depth d of each notch 13 is greater than the radial thickness b of the discharge ring 9 between adjacent notches 13.

[0061] Figure 4 The diagram also shows that five axial protrusions 14 extend axially from the discharge ring 9, which serve as spacers to flexibly maintain spacing when dimensions change.

[0062] The following will discuss Figures 5A-5C The following description is based on an embodiment of the discharge device 8 of the present invention. This embodiment is partially the same as the embodiments of the present invention described above. To avoid repetition, reference is made to the above description, and the corresponding structures are referred to by the same reference numerals.

[0063] One feature of this embodiment is that the contact element 10 is designed as an elastic spring, which is formed inside the discharge ring 9 and extends out of the discharge ring 9 in the circumferential direction. In this embodiment, the extension direction is the same as the rotation direction of the atomizer shaft 2.

[0064] Each contact element 10 transitions to the discharge ring 9 via a rounded section 15, which reduces the notch stress at the transition point between the elastic tongue-shaped contact element 10 and the discharge ring 9.

[0065] It should also be noted that the contact element 10, designed as a spring-loaded contact, has a concave curved contact surface on its inner side. The radius of curvature of this contact surface is smaller than the radius of curvature of the outer surface of the atomizer shaft 2 within the contact area. This design is advantageous because it allows point contact 11, 12 to be formed between the contact element 10 and the outer surface of the atomizer shaft 2, rather than surface contact.

[0066] It should also be noted that the contact element 10, designed as an elastic tongue, can elastically open radially to compensate for the diameter deviation of the atomizer shaft 2.

[0067] Figure 6 It shows Figures 5A-5C The discharge device 8 shown is used on the shaft 2 of a non-stepped atomizer, while Figure 7 It shows Figures 5A-5C The discharge device 8 shown is applied to the stepped atomizer shaft 2.

[0068] This invention is not limited to the preferred embodiments described above. Instead, various variations and improvements exist, all of which utilize the inventive concept of this invention and therefore fall within its protection scope. In particular, this invention also claims protection for the subject matter and technical features of each dependent claim, independent of the claims referenced by each dependent claim, and especially independent of the technical features of the independent claim. Therefore, this invention comprises multiple independently protected inventive aspects.

[0069] Advantages of the invention This invention has many advantages, which will be briefly described below: - First, the present invention enables a compact design of the discharge device; - Within the scope of protection of this invention, the discharge device may be made of conductive plastic; - The discharge device described in this invention is wear-resistant and only produces minimal wear; - The discharge device described in this invention can be designed in various geometries and sizes; - The discharge device and the atomizer shaft are in point contact, so only a small frictional force is generated, resulting in only a correspondingly small mechanical power loss; - The notch on the outside of the discharge ring allows the discharge ring to deflect radially to accommodate various shaft movements of the atomizer shaft; - The discharge device of the present invention is an integral component that can be manufactured in one piece, so its manufacturing cost is lower than that of discharge devices in the prior art; - Unlike carbon fiber bundles in the prior art, the inner diameter of the discharge device described in this invention can be processed with higher precision; - Due to its higher processing precision, the discharge device described in this invention can be put into use without a break-in period.

[0070] List of reference numerals 1. Rotary atomizer 2. Atomizer shaft of a rotary atomizer 3. The distal end of the atomizer shaft 4. Axis of rotation of the atomizer shaft 5. Bearings for rotatable supports of atomizer shafts 6. Housing of the rotary atomizer 7. Rotary atomizer housing end cap 8. Discharge device 9. Discharge ring 10. Contact elements on the discharge ring Point contact between discharge rings 11 and 12 and atomizer shaft 13. The notch on the outer side of the discharge ring for radial deflection. 14. Axial protrusion on the discharge ring 15. Rounding between the elastic spring tongue and the discharge ring a. Axial distance between the discharge ring and the distal end of the atomizer shaft b. Radial thickness of the discharge ring d. Radial depth of the notch on the discharge ring

Claims

1. A discharge device (8) for extracting a high voltage potential from a rotor (2), particularly from the atomizer shaft (2) of a rotary atomizer (1) equipped with an electrostatic coating charging system, comprising: a) A discharge ring (9) that surrounds the rotor (2) in a ring shape; as well as b) At least one conductive contact element (10) is arranged on the discharge ring (9) and in contact with the rotor (2) to extract the high voltage potential from the rotor (2). Its features are, c) The discharge ring (9) and the at least one contact element (10) are integrally formed as a single component (8).

2. The discharge device (8) according to claim 1, characterized in that, a) The integral component (8) is made of a non-metallic and conductive material; and / or b) The integral component (8) is made of conductive plastic.

3. The discharge device (8) according to any one of the preceding claims, characterized in that, a) The integral component (8) includes a plurality of contact elements (10) arranged along the periphery of the discharge ring (9); b) The number of contact elements (10) is preferably more than two, three or four; c) The contact elements (10) are preferably arranged at equal intervals along the periphery of the discharge ring (9); d) Each contact element (10) is preferably designed to form one or more point contacts (11, 12) with the rotor (2) respectively, so as to avoid the formation of an isolating air boundary layer, unlike surface contact, and keep the braking torque of the discharge device (8) at a low level; e) Each contact element (10) preferably extends radially inward from the discharge ring (9).

4. The discharge device (8) according to any one of the preceding claims, characterized in that, a) Each contact element (10) is a radial protrusion extending radially inward from the discharge ring (9); b) The radially inner end faces of the radially protruding portion (10) are all concave and have a specific radius of curvature; and c) The radius of curvature of the inner end face of the radial protrusion (10) is smaller than the radius of curvature of the outer surface of the rotor (2), so that the inner end face of the radial protrusion (10) and the outer surface of the rotor (2) are not in surface contact, but in point contact.

5. The discharge device (8) according to any one of the preceding claims, characterized in that, a) The discharge ring (9) has at least one notch (13) on the outer side to realize the elastic return capability of the discharge ring (9) so that the discharge ring (9) can deflect in the radial direction. b) Preferably, a plurality of notches (13), particularly at least three, four or five notches, are arranged to be distributed on the outer side of the periphery of the discharge ring (9); c) The notches (13) on the outer side of the discharge ring (9) are preferably distributed at equal intervals along the periphery of the discharge ring (9); d) The notch (13) on the outer side of the discharge ring (9) is preferably arranged at the same angular position as the contact element (10), such that at the same angular position, one of the notches (13) is provided on the outer side of the discharge ring (9), and one of the contact elements (10) is provided on the inner side of the discharge ring (9); e) The notches (13) on the outside of the discharge ring (9) preferably have a certain radial depth (d), which is at least 20%, 30%, 40%, 50%, 60%, 70%, 80% or 90% of the radial thickness (b) of the discharge ring (9) next to the notch (13).

6. The discharge device (8) according to any one of the preceding claims, characterized in that, a) The integral component (8) is made of a material significantly softer than the rotor (2) to minimize wear on the rotor (2); and / or b) The integral component (8) is preferably made of plastic; and / or c) The integral component (8) and the rotor (2) form a material pair with a sliding friction coefficient of less than 0.5, 0.3, 0.2, 0.1 or 0.05; and / or d) The integral component (8) is made of a material with a Shore D hardness of less than 90, 80, 70, 60, 50, 40, 30, 20 or 10 to minimize wear on the rotor (2); and / or e) the one-piece component (8) is made of a material having an electrical conductivity of at least 10 -12 S . cm -1 , 10 -10 S . cm -1 , 10 -8 S . cm -1 , 10 -6 S . cm -1 , 10 - 4 S . cm -1 , 10 -2 S . cm -1 , 1S . cm -1 , 10S . cm -1 , 100S . cm -1 ; and / or f) The integral component (8) is made of a wear-resistant material, the wear value of which, as measured according to DIN 53516, is less than 500 mm. 3 300mm 3 200mm 3 100mm 3 50mm 3 Or 20mm 3 .

7. The discharge device (8) according to any one of the preceding claims, characterized in that, a) Multiple axial protrusions (14) extend axially from the circumferential edge of the discharge ring (9) to serve as spacers; b) The axial protrusions (14) are equidistantly distributed along the periphery; c) The axial protrusion (14) is preferably arranged in the circumferential direction between the contact elements (10) and / or between the recesses (13).

8. The discharge device (8) according to any one of the preceding claims, characterized in that, a) The contact element (10) is an elastic tongue formed inside the discharge ring (9), the elastic tongue elastically abutting against the outer circumferential surface of the rotor (2); and / or b) The contact element (10) is designed as a spring-loaded contact, capable of elastic deflection in a plane perpendicular to the rotation axis of the rotor (2); and / or c) A contact element (10) in the form of an elastic tongue extends from the discharge ring (9) in the circumferential direction along or against the rotational direction of the rotor (2); and / or d) The discharge ring (9) is adapted to accommodate a diameter deviation of at least 0.1 mm, 0.2 mm, 0.5 mm, 1 mm, 2 mm or 3 mm on the outer surface of the rotor (2); and / or e) The contact elements (10) designed as elastic tongues are all formed on the discharge ring (9) by rounding (15), and the radius of the rounding is at least 1 mm, 2 mm or 3 mm.

9. The discharge device (8) according to claim 8, characterized in that, a) The contact surface of the contact element (10) designed as an elastic tongue for contacting the side surface of the rotor (2) is concave and curved, and has a specific radius of curvature. as well as b) The radius of curvature of the contact surface of the contact element (10) designed as an elastic tongue is preferably smaller than the radius of curvature of the outer surface of the rotor (2), so that the inner contact surface and the outer surface of the rotor (2) are not in surface contact, but form point contact (11, 12).

10. A rotary atomizer (1) for applying a coating agent, particularly a paint, to components, especially to vehicle body components, comprising: a) Rotatably supported atomizer shaft (2) for rotating the spray body, especially the bell cup; b) An electrostatic coating agent charging system for electrostatically charging the applied coating agent; and c) Discharge device (8) for extracting the high voltage potential from the electrostatic coating charging system from the atomizer shaft (2), Its features are, d) The discharge device (8) is designed according to any one of the preceding claims.

11. The rotary atomizer (1) according to claim 10, characterized in that, The electrostatic coating charging system includes an external charging system with an external charging electrode that is separated from the atomizer shaft (2), so that the atomizer shaft (2) is charged to a high voltage potential by the external charging electrode discharging to the atomizer shaft (2).

12. The rotary atomizer (1) according to claim 11, characterized in that, a) The discharge from the external charging electrode acts on the point of action at the distal end (3) of the atomizer shaft (2), particularly on the bell-shaped cup mounted on the atomizer shaft (2); and b) The integrated component (8) is located at the distal end (3) of the atomizer shaft (2) in a ring around the atomizer shaft (2) and near the point of discharge action. In particular, the axial distance (a) between the integrated component and the distal end (3) of the atomizer shaft (2) is less than 10cm, 7cm, 5cm, 3cm or 2cm.

13. The rotary atomizer (1) according to any one of claims 10 to 12, characterized in that, a) The atomizer shaft (2) is rotatably supported in a bearing (5), particularly an air dynamic bearing (5) or an air static bearing (5); and b) An integral component (8) is arranged axially between the bearing (5) and the far end of the atomizer shaft (2) to avoid high-pressure ablation inside the bearing (5).

14. The rotary atomizer (1) according to any one of claims 10 to 13, characterized in that, a) The integral component (8) is electrically grounded, or at near-ground potential; and / or b) The charging voltage of the electrostatic coating agent charging system is at least 10kV, 20kV, 50kV or 100kV; and / or c) The integral component (8) is in contact with the outer surface of the atomizer shaft (2); and / or d) The atomizer shaft (2) has threads at its distal end so that the spray body can be screwed onto the atomizer shaft (2).

15. Use of a discharge device (8) according to any one of claims 1 to 9 for extracting a high voltage potential on the atomizer shaft (2) of a rotary atomizer (1) equipped with an electrostatic coating charging system.

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