Bell cup and rotary sprayer including such a bell cup

Abstract

The present invention relates to a bell cup (1) for a rotary sprayer (10) for spraying a coating agent (e.g. paint), comprising a spray body (3) with an annular spraying edge (4) for spraying the coating agent, a hub part (13) for mounting the bell cup (1) on a rotatable hollow shaft (11) of the rotary sprayer (10), and a fixing arrangement (17-20, 23, 24) for matingly fixing the bell cup (1) on the hollow shaft (11) of the rotary sprayer (10). According to the invention, the fixing arrangement (17-20, 23, 24) has an annular clamping surface on the outer circumferential surface of the hub part (13) that is inclined with respect to the axis of rotation (2) of the bell cup (1) for abutment with a clamping element (18) of the rotary sprayer (10) in order to clamp the bell cup (1) on the hollow shaft (11) of the rotary sprayer (10) with an axial clamping force.

Description

[Technical field]

[0001] The present invention relates to a bell cup for a rotary sprayer for spraying a coating agent (e.g. paint). Furthermore, the present invention relates to a rotary sprayer equipped with such a bell cup. [Background technology]

[0002] Modern paint installations for painting automotive body parts typically use rotary atomizers as application devices, which use a turbine to rotate a bell cup that sprays paint from an annular spray edge. The bell cup is usually attached to the rotary atomizer turbine shaft by a threaded connection with fine threads. However, this method of fastening the bell cup to the rotary atomizer turbine shaft has various disadvantages.

[0003] One disadvantage of threaded connections is the relatively time consuming cleaning required for the fine threads as they can become contaminated and contamination of the fine threads can also cause an imbalance in the bell cup and in the worst case result in bearing failure.

[0004] Another drawback of the known fastening method is that multiple rotations of the bell cup relative to the turbine shaft are required to screw the bell cup onto the turbine shaft.

[0005] Furthermore, this type of fastening by means of a threaded connection entails the risk that the bell cup may tilt relative to the turbine shaft, which may result in damage to the fine thread into which it is screwed.

[0006] Furthermore, in the event of jerky braking of the bell cup or malfunction of the bearing unit at the turbine of the rotary atomizer, there is a risk of the threaded connection loosening due to the mechanical inertia of the bell cup.

[0007] Finally, reference is made to US Pat. No. 5,399,633, US Pat. No. 5,499,625, US Pat. No. 5,599,635 and US Pat. No. 5,599,625 for the technical background of the present invention. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] International Publication No. 2011 / 009641 [Patent Document 2] US Patent Application Publication No. 2007 / 0090204 [Patent Document 3] U.S. Patent No. 6,341,734 Summary of the Invention [Problem to be solved by the invention]

[0009] In view of the above, an object of the present invention is to provide an improved attachment of a bell cup to a rotary atomizer. [Means for solving the problem]

[0010] The present invention solves this problem by means of a bell cup as claimed in the main claim.

[0011] The bell cup according to the invention serves to be mounted on a rotary atomizer for spraying a coating agent (e.g. paint). It should be noted here that the invention is not limited to bell cups intended for the application of paint. Rather, the bell cup according to the invention may also be designed for the application of other coating agents. The invention is therefore not limited to paint as the coating agent to be applied. It should also be noted that the term bell cup used in the context of the invention should be interpreted in a general sense and includes, for example, the spray disk of a disk atomizer. However, preferably, the bell cup according to the invention is a bell cup in the literal sense.

[0012] Like known bell cups, the bell cup according to the invention firstly comprises a spray body with an annular, circumferential spray edge for spraying the coating agent.

[0013] Moreover, like known bell cups, the bell cup according to the invention has a hub part for mounting the bell cup on a rotatable hollow shaft of a rotary atomizer. It should be noted that in a preferred embodiment of the invention, the hub part and the spray body are separate parts that can be connected to each other, for example by a threaded connection. However, within the scope of the invention, it is also possible instead for the spray body and the hub part to be integral and form together a single part.

[0014] Furthermore, the bell cup according to the present invention also provides a fixing arrangement for matingly fixing the bell cup to the hollow shaft of the rotary atomizer.

[0015] Here, the bell cup according to the invention is distinguished from the prior art in terms of the structural design and functionality of this fastening arrangement. In contrast to the prior art, the fastening arrangement is therefore not a threaded connection. Instead, in the case of the bell cup according to the invention, the fastening arrangement has, on the outer circumferential surface of the hub part, an annular, circumferential clamping surface inclined with respect to the axis of rotation of the bell cup, which forms, in the assembled state, an abutment surface for abutment with a clamping element (e.g. a clamping ball) of the rotary sprayer, in order to clamp the bell cup on the hollow shaft of the rotary sprayer with an axial clamping force. The fastening arrangement according to the invention is therefore not characterised by a threaded connection, but rather provides a clamping connection. Within the scope of the invention, therefore, the connection between the bell cup on the one hand and the hollow shaft of the rotary sprayer on the other hand is preferably made without a threaded connection. However, it is pointed out for the avoidance of doubt that the fastening arrangement according to the invention may also have threaded connections between the individual parts of the fastening arrangement. However, these threaded connections do not serve to establish a connection between the bell cup on the one hand and the hollow shaft of the rotary sprayer on the other hand.

[0016] The fixing arrangement according to the invention serves firstly to mechanically fix the bell cup on the hollow shaft of the rotary sprayer. In addition, the fixing arrangement according to the invention may also perform other functions, in particular the centering of the bell cup on the hollow shaft of the rotary sprayer. For this, the hub part of the bell cup may have a centering cone on the outside for abutment with a complementary centering cone in the hollow shaft of the rotary sprayer. The hollow shaft of the rotary sprayer thus has a centering cone on the inside at its distal end, which widens in the distal direction. Correspondingly, the centering cone on the hub part of the bell cup has a centering cone on the outside that tapers in the proximal direction. The two centering cones of the hub part on the one hand and the hollow shaft of the rotary sprayer on the other hand are preferably coaxial with the axis of rotation of the bell cup and have the same cone angle to allow a good centering effect.

[0017] When the bell cup is mounted on the hollow shaft of the rotary sprayer, the above-mentioned clamping connection generates an axial clamping force which presses the bell cup axially against the hollow shaft of the rotary sprayer. This presses the conical surfaces of the two centering cones of the hub part on the one hand and the hollow shaft of the rotary sprayer on the other hand against each other in the axial direction, resulting in a good centering effect. It is desired to achieve an axial position of the bell cup as accurate as possible in the assembled state. The hub part of the bell cup then preferably has a flat surface on the outside for forming an axial stop for the bell cup. The flat surface on the hub part then preferably runs annularly and concentrically around the rotation axis of the bell cup, and is preferably aligned perpendicularly to the rotation axis of the bell cup. And the flat surface on the hub part of the bell cup is placed against the end face of the hollow shaft of the rotary sprayer in the assembled state, thus forming an axial stop. The flat surface on the hub part of the bell cup preferably adjoins the centering cone in the axial direction along the rotation axis, and said flat surface is preferably located axially between said centering cone and the spray edge of the bell cup.

[0018] The above-mentioned clamping connection between the bell cup on the one hand and the hollow shaft of the rotary sprayer on the other hand is preferably established by a clamping ring, which is not part of the bell cup but is located in an associated fixed arrangement in the hollow shaft of the rotary sprayer. This clamping ring is preferably screwed onto the hollow shaft of the rotary sprayer. This means that a rotation of the clamping ring in the hollow shaft of the rotary sprayer also results in a corresponding axial displacement of the clamping ring, which can be used to create the required axial clamping force. The rotation of the clamping ring to create the required clamping force is preferably performed by the bell cup during assembly of the bell cup. For this purpose, the hub part of the bell cup may have a receptacle for a driver, which projects axially from the clamping ring in the hollow shaft of the rotary sprayer as a projection and, in the assembled state, projects axially into a receptacle in the hub part of the bell cup, so that when the bell cup is rotated during assembly, it also rotates the clamping ring. When mounting the bell cup on the rotary sprayer, the bell cup is first placed on the hollow shaft so that the driver on the clamp ring projects into a receptacle in the hub portion of the bell cup. The bell cup is then rotated, causing the clamp ring to rotate, resulting in a corresponding axial displacement of the clamp ring. The clamp ring is then rotated until the centering cones on the hollow shaft of one rotary sprayer and on the hub portion of the other are in contact with each other and the flat surface of the hub portion abuts the end face of the hollow shaft.

[0019] Furthermore, the invention further comprises an inventive aspect relating to the rinsing of the bell cup. Thus, like the known bell cup, the bell cup according to the invention has an outer peripheral surface, which is for example conical in shape and continues on the outside to the spray edge of the bell cup. This outer peripheral surface can become dirty during the painting operation and must be cleaned from time to time. For this reason, like the known bell cup, the bell cup according to the invention preferably has an outer rinsing chamber, which is preferably located on the rear side of the bell cup. Then, during the rinsing process, the rinsing agent is introduced into the outer rinsing chamber of the bell cup. Then, from the outer rinsing chamber, the rinsing agent automatically passes onto the outer peripheral surface of the bell cup, as a result of which the cleaning of the outer peripheral surface is carried out there. In this case, the distribution of the rinsing agent on the outer peripheral surface of the bell cup can be promoted by shaping air which is blown from behind, substantially axially, onto the outer peripheral surface of the bell cup.

[0020] To introduce the rinsing agent into the outer rinsing chamber, the bell cup according to the invention, like known bell cups, has an outer rinsing channel which starts from the rinsing agent supply inside the bell cup and opens into the outer rinsing chamber at an outlet opening. The operation of such an outer rinsing system is also described, for example, in EP 0 715 896 A and EP 2 464 459 A.

[0021] As already mentioned above, the hub part on the one hand and the spray body on the other hand may be separate parts that are connected to each other, for example by a threaded connection, in particular by an internal thread on the hub part and an external thread on the spray body of the bell cup. This allows the outer rinse channel to extend between the hub part and the spray body over part of its length. It is worth noting here that the outer rinse channel in the area between the hub part and the spray body is preferably an annular channel running around the entire circumference.

[0022] As already mentioned above, the outer rinsing channel opens at its outlet opening into the outer rinsing chamber of the bell cup in order to introduce the rinsing agent into the outer rinsing chamber. Here, in the area between the hub part and the spray body, the outer rinsing channel can form a deflection which causes a change in the direction of the flow of the rinsing agent in the outer rinsing channel. Thus, the flow of the rinsing agent in the outer rinsing channel upstream of the outlet opening preferably flows in a distal direction obliquely relative to the rotation axis of the bell cup. And downstream after the deflection, the rinsing agent preferably enters the outer rinsing chamber in a proximal direction, where different outlet angles relative to the rotation axis of the bell cup are possible.

[0023] In one variant of the invention, the flow of rinsing agent enters the outer rinsing chamber from the outlet opening of the outer rinsing channel essentially parallel to the axis of rotation of the bell cup, where a tolerance range of ±10°, ±5° or ±2° is possible.

[0024] In another variation of the invention, on the other hand, the flow of rinsing agent exiting the outlet opening of the outer rinsing channel and entering the outer rinsing chamber is inclined outward, for example at an outlet angle of 15° relative to the axis of rotation of the bell cup, where tolerance ranges of ±10°, ±5° or ±2° are possible.

[0025] In yet another variant of the invention, on the other hand, the flow of rinsing agent leaving the outlet opening of the outer rinsing channel and entering the outer rinsing chamber is inclined inwards, in particular with an outlet angle of at least 15°, 20° or 25° relative to the axis of rotation of the bell cup, with possible tolerance ranges of ±10°, ±5° or ±2°. The purpose of this inward inclination is to allow the rinsing agent to peel off at the edges and swirl to reach everywhere.

[0026] In the context of the present invention, the above-mentioned aspects of the invention relating to the outer rinse have their own protection meaning independently of the other aspects of the invention, in particular independently of the fixing arrangement according to the invention.

[0027] As already mentioned at the beginning, the spray body and the hub part may be integral and thus form a single part, however, in a preferred embodiment of the invention it is provided that the spray body on the one hand and the hub part on the other hand are separate parts which are mechanically connected to each other, for example by a screw connection of the hub part to the spray body, in particular by an internal thread on the hub part and an external thread on the spray body.

[0028] In addition to the bell cup according to the invention described above, the invention also claims protection for a correspondingly adapted rotary atomizer.

[0029] Firstly, like known rotary atomizers, the rotary atomizer according to the invention has a rotatably mounted hollow shaft for rotating a bell cup during operation, the hollow shaft being capable of being driven, for example, by a turbine, which is known per se from the prior art and will not be described in detail.

[0030] Like known rotary atomizers, the rotary atomizer according to the invention also has a fixing arrangement making it possible to fix the bell cup in a snap-fit ​​manner on the hollow shaft of the rotary atomizer.

[0031] In the known rotary sprayers, the fixing arrangement, as already mentioned, allows a screw connection between the bell cup on the one hand and the hollow shaft of the rotary sprayer on the other hand. In the rotary sprayer according to the invention, it is provided on the one hand that the fixing arrangement in the hollow shaft of the rotary sprayer has at least one clamping element (e.g. a clamping ball) for abutment with a corresponding clamping surface on the hub part of the bell cup in order to clamp the bell cup on the hollow shaft of the rotary sprayer with an axial clamping force.

[0032] In a preferred embodiment of the invention, the at least one clamping element is a clamping ball having a radial range of motion within the hollow shaft of the rotary sprayer, and in a radially inner clamping position, the clamping element clamps the bell cup onto the hollow shaft of the rotary sprayer, whereas in a radially outer open position, the clamping element opens the bell cup to allow assembly or disassembly of the bell cup.

[0033] Here, a cage (e.g. a ball cage) is preferably provided for radially movably mounting the clamping element within the hollow shaft of the rotary sprayer, said cage being preferably arranged with the clamping elements (e.g. clamping balls) inside the hollow shaft of the rotary sprayer, for example the cage can be screwed with its male thread into a corresponding female thread of the hollow shaft of the rotary sprayer.

[0034] As already mentioned briefly above, the clamping elements (e.g. clamping balls) are radially movable between an outer open position and an inner clamped position. For the movement of the clamping elements from the outer open position to the inner clamped position, a clamping ring may be provided, which may be arranged in the annular gap between the cage and the hollow shaft of the rotary sprayer. This clamping ring is preferably connected to the hollow shaft of the rotary sprayer by a threaded connection having an external thread on the clamping ring and an internal thread in the hollow shaft of the rotary sprayer, so that a rotation of the clamping ring relative to the hollow shaft of the rotary sprayer results in a corresponding axial displacement of the clamping ring in the hollow shaft of the rotary sprayer. At its proximal end, the clamping ring preferably has a clamping surface that is inclined with respect to the axis of rotation of the bell cup and widens in the proximal direction, so that when the clamping ring moves in the proximal direction, it presses the clamping elements radially inwards to the clamped position. Then, during the fastening process, the clamp ring is rotated within the hollow shaft, which results in a corresponding axial displacement of the clamp ring, and as a result, the clamp ring ultimately presses at least one clamping element (e.g., a clamping ball) from an outer, open position to an inner, clamped position.

[0035] It should be noted here that during actual painting operation, centrifugal forces act on the clamping elements due to the high speed of the hollow shaft of the rotary sprayer, which push the clamping elements radially outwards. Due to these centrifugal forces, the clamping elements (e.g. clamping balls) push against the clamping surfaces of the clamping ring during operation, which results in an axial tension between the clamping ring on the one hand and the hollow shaft of the rotary sprayer on the other hand, so that the friction forces in the threaded connection between the clamping ring and the hollow shaft increase with speed. This opposes loosening of the threaded connection during painting.

[0036] As already mentioned above, the clamp ring is rotated during the fastening process, which results in a corresponding axial displacement of the clamp ring within the hollow shaft of the rotary atomizer. This rotation of the clamp ring is preferably caused by a bell cup, which is first placed on the turbine shaft and then rotated relative to the turbine shaft during the fastening process. This rotation of the clamp ring by the bell cup is made possible by a driver projecting axially distally from the clamp ring and fitting into a corresponding receptacle in the hub of the bell cup, so that when the bell cup is rotated during assembly or disassembly, it also rotates the clamp ring.

[0037] In the assembled state, a given axial clamping force acts on the rotatable clamping ring, where this axial clamping force is converted by the inclination of the clamping surface of the clamping ring into a corresponding surface-normal clamping force, which acts on the clamping elements (e.g. clamping balls). The clamping surface of the clamping ring is inclined with respect to the rotation axis of the bell cup such that a given force transmission ratio results between the axial clamping force on the clamping ring on the one hand and the surface-normal clamping force on the clamping elements on the other hand. This force transmission ratio is preferably at most 1:8, preferably greater than 1:1, 1:2, 1:4 or 1:6. The surface-normal clamping force on the clamping elements is therefore preferably substantially greater than the axial clamping force on the clamping ring.

[0038] Furthermore, it should be noted that in the screw connection between the clamping ring on the one hand and the hollow shaft of the rotary sprayer on the other hand, a certain friction force occurs which depends on the axial clamping force on the clamping ring, the ratio between the friction force of the screw connection on the one hand and the axial clamping force on the clamping ring on the other hand is preferably at least 0.5:1, 1:1 or 1:2, preferably at most 1:6.

[0039] In a preferred embodiment of the invention, the cage (e.g. ball cage) preferably comprises several sets of clamping elements (e.g. clamping balls), where the sets of clamping elements may be distributed over the circumference. In a preferred embodiment of the invention, the sets of clamping elements are evenly distributed over the circumference, e.g. three sets may be provided. The distance between the clamping elements in a set of clamping elements here is preferably smaller than the distance between the clamping elements of adjacent sets.

[0040] Additionally, it is worth noting that at least one clamping element (eg, clamping ball) is made from, for example, steel, ceramic, plastic, or glass, to name just a few materials.

[0041] It should be noted here that at least one clamping element (e.g. clamping ball) is arranged in operation on the corresponding part, which is a clamping surface, which is preferably formed on the hub part of the bell cup. Here, it is advantageous for the at least one clamping element (e.g. clamping ball) on the one hand and the clamping surface on the other hand to be made of different materials, since such material combinations have proven to be advantageous. For example, the clamping surface or the hub part can be made of steel, in particular hardened steel, while the at least one clamping element (e.g. clamping ball) can be made of ceramic. However, within the scope of the invention, other material combinations of materials with different material properties, in particular with regard to hardness, can also be used.

[0042] The individual clamping elements (eg clamping balls) preferably have a diameter in the range of 1 mm-5 mm.

[0043] It is further noted that the number of clamping elements may be, for example, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12.

[0044] Furthermore, it should be noted that the clamping connection between the inclined clamping surface of the clamping ring on the one hand and the clamping elements (eg clamping balls) on the other hand is preferably self-locking.

[0045] It is also worth noting that the clamp ring may have corrugated sections in the longitudinal sections to make the clamp ring resiliently flexible in the axial direction.

[0046] As already mentioned above, the actual connection between the rotary sprayer on the one hand and the bell cup on the other hand is not made by a threaded connection, but by a modern clamping connection. However, even in the fixed system according to the invention, the fixing arrangement in the rotary sprayer and in the bell cup preferably comprises a threaded connection. Here, there is a risk that such a threaded connection may loosen during operation. For example, the blocking of the hollow shaft of the rotary sprayer leads to a jerky braking of the hollow shaft, as a result of which the threaded connection is also subjected to a corresponding torque. In this case, it is advantageous that the torque occurring during such blocking does not lead to a loosening of the threaded connection, but to a tightening of the threaded connection. This is then advantageous, since in the case of blocking of the hollow shaft of the rotary sprayer, there is no risk that the bell cup will come off the rotary sprayer. The threaded connection is therefore preferably a right-hand thread, while the rotary sprayer is designed to rotate the hollow shaft preferably to the left in the painting operation, i.e. counterclockwise when viewed axially in the distal direction. Braking or even blocking of the hollow shaft of the rotary sprayer then causes the threaded connection to tighten.

[0047] Other advantageous further embodiments of the invention are indicated in the dependent claims and are explained in more detail below together with the description of preferred embodiments of the invention with reference to the drawings. [Brief description of the drawings]

[0048] [Figure 1] 1 shows a cross-sectional view of a bell cup according to the present invention attached to a rotary atomizer. [Diagram 2] FIG. 2 shows a detailed view of FIG. 1 of a clamping ball for clamping the bell cup onto the hollow shaft of the rotary atomizer. [Diagram 3] FIG. 2 is a detailed view of FIG. 1 illustrating an external rinse according to the present invention, with the thick arrows indicating the flow path of the rinse agent. [Figure 4A] 4A-4C show different variations of the invention for external rinsing with different exit angles of the rinsing liquid into the outer rinsing chamber of the bell cup. [Figure 4B] See legend to Figure 4A. [Figure 4C] See legend to Figure 4A. [Diagram 5] FIG. 2 shows a perspective view of a bell cup according to the invention with a fixing arrangement according to the invention. [Figure 6] FIG. 2 shows a cross-sectional view of a fixing arrangement according to the invention with three sets of clamping balls. [Figure 7] FIG. 2 shows a detail of FIG. 1 with the centering cone of the bell cup on the one hand and the hollow shaft on the other hand. [Figure 8A] 8A-8D show various stages during an assembly run. [Figure 8B] See legend to Figure 8A. [Figure 8C] See legend to Figure 8A. [Figure 8D] See legend to Figure 8A. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0049] In the following, an embodiment of the invention is described, which is illustrated in the drawings.

[0050] The drawings therefore show a bell cup 1 which is of partly conventional construction and which rotates in operation about an axis of rotation 2, as will be described in more detail below. As is conventional, the bell cup 1 includes a spray body 3 having an annular, circumferential spraying edge 4 for spraying the paint to be applied.

[0051] A distribution disk holder 5 is arranged in the center of the spray body 3 on its end face, and a distribution disk 6 is fixed to the distribution disk holder 5. The distribution disk 6 has the role of dispersing the centrally and axially fed paint radially outwardly on an overflow surface 7, so that the paint passes outwardly along the overflow surface 7 towards the annular and circumferential spray edge 4 and is sprayed from there.

[0052] Furthermore, the spray body 3 of the bell cup 1 comprises a conical, distally expanding outer circumferential surface 8 which is continuous with the spray edge 4. During the painting operation, the outer circumferential surface 8 becomes soiled with paint residues, which makes it necessary from time to time to clean the outer circumferential surface 8 of the bell cup 1. For this reason, the spray body 3 comprises an outer rinsing chamber 9 at its rear side, into which rinsing agent is introduced during a cleaning operation, which will be described in more detail below. Due to centrifugal force, the rinsing agent automatically passes outward from the outer rinsing chamber 9 onto the outer circumferential surface 8 of the bell cup 1, where the distribution of the rinsing agent on the outer circumferential surface 8 may be assisted by shaping air, which is blown axially against the outer circumferential surface 8 from behind.

[0053] Furthermore, the drawing shows a rotary atomizer 10 having a hollow shaft 11 which is rotated by a compressed air turbine, which, for the sake of simplicity, is not shown since it is itself known from the prior art.

[0054] At its distal end, the hollow shaft 11 has an internal centering cone 12, as can be seen in particular in Figure 7. The centering cone 12 serves for the correct centering of the bell cup 1 on the hollow shaft 11 of the rotary atomizer 10, as will be described in more detail below.

[0055] The bell cup 1 further comprises a hub portion 13 which is tightly screwed onto the spray body 3 of the bell cup 1 .

[0056] The hub part 13 also has an external centering cone 14, as can be seen in particular from Figure 7. The centering cones 12, 14 of the hollow shaft 11 of the rotary atomizer 10 on the one hand and the hub part 13 of the bell cup 1 on the other hand have the same cone angle and are arranged adjacent to one another in the assembled state, as can be clearly seen in particular from Figure 7, so that the bell cup 1 is centered on the hollow shaft 11 of the rotary atomizer 10.

[0057] Furthermore, the hub part 13 of the bell cup 1 has an annular, circumferential flat surface 15 which is aligned perpendicular to the axis of rotation 2 of the bell cup 1, as can be seen in particular from Fig. 7. The flat surface 15 forms an axial stop for the bell cup 1 and, in the assembled state, is arranged against an end face 16 of the hollow shaft 11 of the rotary atomizer 10, as can be clearly seen from Fig. 7. The centering cones 12, 14, which, in the assembled state of the bell cup 1, are arranged against one another, provide centering, while the flat surface 15 forms an axial stop for the bell cup 1 with its end face 16.

[0058] A ball cage 17 threads onto the hollow shaft 11 of the rotary sprayer 10 and radially moveably and non-removably holds a number of clamping balls 18. The clamping balls 18 have a radial range of motion between an outer open position and an inner clamped position, as will be described in more detail below.

[0059] In the annular gap between the ball cage 17 and the hollow shaft 11 of the rotary sprayer 10 is a clamping ring 19, which is screwed onto the hollow shaft 11 of the rotary sprayer 10 by means of a threaded connection 20. Rotation of the clamping ring 19 within the hollow shaft 11 also results in a corresponding axial displacement of the clamping ring 19 within the hollow shaft 11, which is used in a fastening process, which will be described in more detail below.

[0060] At its proximal end, the clamping ring 19 has a clamping surface 21 that is inclined with respect to the axis of rotation 2 of the bell cup 1, as shown in particular in Figure 2. During the clamping process, the clamping surface 21 can press against the clamping ball 18 and urge it from a radially outer open position to a radially inner clamped position.

[0061] The hub portion 13 of the bell cup 1 has a corresponding clamping surface 22 at its proximal end such that when the clamp ring 19 urges the clamping ball 18 with its clamping surface 21 from a radially outer open position to a radially inner clamped position, the clamping ball 18 is forced against the clamping surface 22 on the hub portion 13, thereby clamping the bell cup 1 axially onto the hollow shaft 11 of the rotary atomizer 10.

[0062] FIG. 2 shows the clamp ring 19 applied with a predetermined axial clamping force F AXIAL The inclination of the clamping surface 21 of the clamping ring 19 with respect to the rotation axis 2 of the bell cup 1 creates a normal clamping force F SPANN acts on the clamping balls 18. Thus, the inclination of the clamping surface 21 results in an axial clamping force F AXIAL and normal clamping force F SPANN The force transformation between the normal clamping force F and the clamping force F is, for example, 1:4. SPANN is the axial clamping force F AXIAL The force transmission ratio may be four times as large as the force transmission ratio of the axial force.

[0063] As already mentioned above, the rotation of the clamp ring 19 relative to the hollow shaft 11 of the rotary sprayer 10 by means of the threaded connection 20 results in a corresponding axial displacement of the clamp ring 19, whereby the bell cup 1 is axially clamped on the hollow shaft 11. The rotation of the clamp ring 19 required for this is provided by the bell cup 1, which for this purpose is inserted with its hub part 13 into the hollow shaft 11. The driver 23 on the clamp ring 19 then projects into a corresponding receptacle 24 in the hub part 13 of the bell cup 1. When the bell cup 1 is rotated, the driver 23 is then also rotated in conjunction with the receptacle 24, which in turn results in a rotation of the clamp ring 19.

[0064] After the bell cup 1 is placed into the rotary atomizer 10, rotation of the bell cup 1 in turn results in a corresponding rotation of the clamp ring 19, which is also displaced axially during the process. The axial displacement of the clamp ring 19 then causes the clamping balls 18 to press radially inward against the clamping surface 22 at the proximal end of the hub portion 13, resulting in the hub portion 13 being axially clamped within the hollow shaft 11.

[0065] Furthermore, it should be noted that the hub part 13 on the one hand and the spray body 3 of the bell cup 1 on the other hand are separate parts which are connected to one another by a screw connection 25, as can be seen for example from Fig. 3. This advantageously allows an external rinsing of the outer peripheral surface 8 of the bell cup 1. Thus, a paint nozzle 26 extends into the hollow shaft 11 of the rotary sprayer 10, which has a dual role, as also described in EP 2 464 459 B1.

[0066] Firstly, the paint nozzle 26 delivers the paint to be applied via a central paint channel 27, which then axially impacts the distribution disc 7 and is deflected outwards.

[0067] Secondly, the paint nozzle, as can be seen in particular from Fig. 3, comprises an outer rinsing channel 28. The outer rinsing channel 28 also guides the rinsing agent forwards towards the distribution disc 6. In addition, a further outer rinsing channel 29 branches off from the outer rinsing channel 28 and guides a part of the rinsing agent outwards into the outer rinsing chamber 9. In a section 30, the outer rinsing channel 29 extends between the hub part 13 and the spray body 3 and forms there an annular channel. At its outlet opening 31, the outer rinsing channel 29 then opens into the outer rinsing chamber 9.

[0068] In the area of ​​the outlet opening 31, as can be seen from the various variants of Figures 4A-4C, the outer rinsing channel 29 forms a deflection for the flow of the rinsing agent, which therefore leaves the outlet opening 31 at an outlet angle α relative to the axis of rotation 2.

[0069] In the variant of the invention according to FIG. 4A, the outlet angle α=0°, ie the rinsing agent leaves the outlet opening 31 in the proximal direction parallel to the axis of rotation 2 .

[0070] In the variant of the invention according to FIG. 4B, on the other hand, the flow of rinsing agent is inclined outwards at an angle of approximately α=15°.

[0071] In the variant of the invention according to Figure 4C, on the other hand, the flow of rinsing agent at the outlet opening 31 is inclined inwards at an angle of approximately α = 15°. The purpose of this inward inclination is to allow the rinsing agent to peel off at the edges and swirl around to reach everywhere.

[0072] 8A-8C show different stages in the assembly of the bell cup 1 on the hollow shaft 11 of the rotary atomizer 10.

[0073] At the assembly stage depicted in FIG. 8A, the bell cup 1 is still completely separate from the rotary atomizer 10.

[0074] However, at the assembly stage depicted in Figure 8B, the bell cup 1 with the hub portion 13 is already inserted into the hollow shaft 11 of the rotary atomizer 10. The clamping balls 18 are still in their radially outer open position.

[0075] In the assembly stage according to Fig. 8C, the bell cup 1 has already been placed further axially on the hollow shaft 11 of the rotary atomizer 10. However, the bell cup 1 is not yet at its axial stop, which is formed by the flat surface 15 on the hub part 13 on the one hand and the end face 16 of the hollow shaft 11 on the other hand.

[0076] Figure 8D shows the final assembly stage, where the flat surface 15 on the hub portion 13 of the bell cup 1 is in contact with the end face 16 of the hollow shaft 11 of the rotary atomizer 10, thus forming an axial stop.

[0077] Furthermore, the conical surfaces of the centering cones 12 , 14 are disposed in contact with one another, causing the bell cup 1 to be accurately centered on the hollow shaft 11 of the rotary atomizer 10 .

[0078] Furthermore, the clamping ring 19 is rotated in the threaded connection 20 to such an extent that it is displaced axially such that its clamping surface 21 presses the clamping balls 18 radially inwards into a clamped position where the clamping balls 18 press against a clamping surface 22 at the proximal end of the hub part 13, thereby axially clamping the hub part 13 and thus also the entire bell cup 1 on the hollow shaft 11.

[0079] Additionally, it should be noted that the clamp ring 19 has a corrugated section 32 that allows for resilient flexibility of the clamp ring 19 in the axial direction.

[0080] Finally, FIG. 6 also shows that there are three sets of clamping balls 18 distributed around the circumference.

[0081] The present invention is not limited to the preferred embodiment described above. Rather, the present invention also encompasses various further embodiments that use the concept of the present invention and fall within the scope of protection. In particular, the present invention also claims protection for the subject matter and features of the dependent claims independently of the claims to which they refer, in particular without the features of the main claim. The present invention therefore includes several aspects of the invention that enjoy protection independent of each other. These aspects of the invention include the external rinse, centering and axial stop described above, to name just a few.

[0082] [Note] [Appendix 1] A bell cup (1) for a rotary atomizer (10) for spraying a coating material, in particular a paint, comprising: a) a spray body (3) having an annular, circumferential spray edge (4) for spraying the coating agent; b) a hub portion (13) for mounting the bell cup (1) on the rotatable hollow shaft (11) of the rotary atomizer (10); c) a fixing arrangement (17-24) for matingly fixing the bell cup (1) to the hollow shaft (11) of the rotary atomizer (10); Equipped with d) A bell cup (1), characterized in that the fixing arrangement (17-24) has an annular, circumferential clamping surface (22) on the outer surface of the hub part (13) inclined with respect to the axis of rotation (2) of the bell cup (1) for abutment with a clamping element (18) of the rotary sprayer (10) in order to clamp the bell cup (1) on the hollow shaft (11) of the rotary sprayer (10) with an axial clamping force.

[0083] [Appendix 2] a) the hub portion (13) of the bell cup (1) includes an external centering cone (14) for abutment with a complementary shaped centering cone (12) in the hollow shaft (11) of the rotary atomizer (10); b) the centering cone (14) on the bell cup (1) is preferably tapered in the proximal direction; c) the centering cone (14) on the bell cup (1) is preferably coaxial with the axis of rotation (2) of the bell cup (1); A bell cup (1) as described in Appendix 1.

[0084] [Appendix 3] a) the hub portion (13) of the bell cup (1) includes an external flat surface (15) for abutment with an end face (16) of the hollow shaft (11) of the rotary atomizer (10), the flat surface (15) forming an axial stop; b) said flat surface (15) is preferably annular and circumferential with respect to the axis of rotation (2) of said bell cup (1); c) the flat surface (15) is preferably coaxial with the axis of rotation (2) of the bell cup (1); d) said flat surface (15) is preferably aligned essentially perpendicular to the axis of rotation (2) of said bell cup (1); e) the flat surface (15) is preferably axially adjacent to the centering cone (14); f) the flat surface (15) is preferably located axially between the centering cone (14) and the spray edge (4); 3. A bell cup (1) according to claim 1 or 2.

[0085] [Appendix 4] the hub portion (13) of the bell cup (1) has a receptacle (24) for a driver (23) which projects axially from a clamp ring (19) in the hollow shaft (11) of the rotary atomizer (10) as a protrusion and, in an assembled state, projects axially into the receptacle in the hub portion (13) of the bell cup (1) so that when the bell cup (1) is rotated during assembly, it rotates the clamp ring (19); A bell cup (1) according to any one of appendixes 1 to 3.

[0086] [Appendix 5] a) an outer peripheral surface (8) of the bell cup (1) which is contiguous with the spray edge (4) and which preferably widens in the spray direction, in particular conically; b) an outer rinsing chamber (9) for rinsing the outer peripheral surface (8) of the bell cup (1) with a rinsing agent, the outer rinsing chamber (9) being located behind the bell cup (1) and preferably having an annular shape; c) at least one outer rinsing channel (29, 30) for supplying said rinsing agent, originating from a rinsing agent supply inside said bell cup (1) and opening into said outer rinsing chamber (9) at an outlet opening (31); Equipped with d) the hub part (13) and the spray body (3) are separate parts connected to each other, in particular by a threaded connection of the hub part (13) to the spray body (3), in particular by an internal thread on the hub part (13) and an external thread on the spray body (3); e) the outer rinse channel (29, 30) extends between the hub part (13) and the spray body (3) over a section (30) of the length of the outer rinse channel (29, 30), in particular before the outlet opening (31) of the outer rinse channel (29, 30) into the outer rinse chamber (9); f) the outer rinse channel (29, 30) in the section (30) between the hub portion (13) and the spray body (3) is preferably an annular channel running around the entire circumference; 5. A bell cup (1) according to any one of claims 1 to 4.

[0087] [Appendix 6] a) the outer rinse channels (29, 30) form a deflection in the section (30) between the hub part (13) and the spray body (3) with a change in the direction of flow of the rinsing agent in the outer rinse channels (29, 30); b) the rinsing agent in the outer rinsing channels (29, 30) upstream of the outlet opening (31) of the outer rinsing channel preferably flows in a distal direction; c) the rinsing agent is discharged from the outlet opening (31) of the outer rinsing channel, preferably in a proximal direction, into the outer rinsing chamber (9); The bell cup (1) described in Appendix 5.

[0088] [Appendix 7] a) the flow of the rinsing agent leaving the outlet opening (31) of the outer rinsing channel and entering the outer rinsing chamber (9) is aligned essentially parallel to the axis of rotation (2) of the bell cup (1), in particular within a tolerance range of ±10°, ±5° or ±2°, or b) the flow of rinsing agent leaving the outlet opening (31) of the outer rinsing channel and entering the outer rinsing chamber (9) is inclined outwards, in particular with a tolerance range of ±10°, ±5° or ±2°, in particular with an outlet angle (α) of 15° with the axis of rotation (2) of the bell cup (1), or c) the flow of the rinsing agent leaving the outlet opening (31) of the outer rinsing channel and entering the outer rinsing chamber (9) is inclined inwards, in particular with an outlet angle (α) of at least 15°, 20° or 25° with the axis of rotation (2) of the bell cup (1), in particular within a tolerance range of ±10°, ±5° or ±2°, Bell cup (1) as described in Appendix 6.

[0089] [Appendix 8] a) the spray body (3) and the hub portion (13) are integral and together form a single part, or b) the spray body (3) and the hub part (13) are separate parts connected to each other, in particular by a threaded connection (25) of the hub part (13) to the spray body (3), in particular by an internal thread on the hub part (13) and an external thread on the spray body (3); 8. A bell cup (1) according to any one of claims 1 to 7.

[0090] [Appendix 9] A rotary atomizer (10) for spraying a coating material, in particular a paint, comprising: a) a rotatably mounted hollow shaft (11) for rotating a bell cup (1), in particular a bell cup (1) according to any one of claims 1 to 8, b) a fixing arrangement (17-24) for matingly fixing the bell cup (1) to the hollow shaft (11) of the rotary atomizer (10); having c) the rotary sprayer (10), characterized in that the fixing arrangement (17-24) comprises at least one clamping element (18) for abutment with a clamping surface (22) of the bell cup (1) in the hollow shaft (11) of the rotary sprayer (10) for clamping the bell cup (1) on the hollow shaft (11) of the rotary sprayer (10) with an axial clamping force.

[0091] [Appendix 10] a) at least one of said clamping elements (18) is a rolling element, in particular a clamping ball (18), and / or b) the clamping element (18) has a radial range of motion within the hollow shaft (11) of the rotary atomizer (10); and / or c) the clamping element (18) in its radially inner clamping position clamps the bell cup (1) onto the hollow shaft (11) of the rotary atomizer (10); and / or d) the clamping elements (18) in their radially outer open position open the bell cup (1) to allow assembly or disassembly of the bell cup (1); 10. The rotary atomizer (10) of claim 9.

[0092] [Appendix 11] a) a cage (17) is provided for radially movably retaining the clamping element (18) within the hollow shaft (11) of the rotary atomizer (10); b) the cage (17) is arranged in the hollow shaft (11) of the rotary sprayer (10) together with the clamping element (18); c) said cage (17) is preferably substantially hollow cylindrical in shape; d) the cage (17) is preferably male-threaded and screwed into the female-threaded hollow shaft (11) of the rotary atomizer (10); 11. The rotary atomizer (10) of claim 10.

[0093] [Appendix 12] a) a clamping ring (19) is provided for moving the clamping element (18) from the outer, open position to the inner, clamped position; b) the clamp ring (19) is disposed in the annular gap between the cage (17) and the hollow shaft (11) of the rotary atomizer (10); c) the clamp ring (19) is connected to the hollow shaft (11) of the rotary sprayer (10) by a threaded connection (20) having male threads on the clamp ring (19) and female threads in the hollow shaft (11) of the rotary sprayer (10), such that rotation of the clamp ring (19) results in a corresponding axial displacement of the clamp ring (19) within the hollow shaft (11) of the rotary sprayer (10); d) the clamping ring (19) has a clamping surface (21) at its proximal end that is inclined with respect to the axis of rotation (2) of the bell cup (1) and that extends in a proximal direction, so that the clamping ring (19) pushes the clamping elements (18) radially inwardly into the clamped position when moving in the proximal direction; 12. The rotary atomizer (10) of claim 11.

[0094] [Appendix 13] the clamping elements (18) are pressed outwardly against the clamping surface of the clamping ring (19) due to the centrifugal forces generated when the hollow shaft (11) rotates during a coating operation, thereby axially fixing the threaded connection (20) between the clamping ring (19) and the hollow shaft (11) of the rotary sprayer (10), so that the frictional forces in the threaded connection (20) between the clamping ring (19) and the hollow shaft (11) increase with the rotational speed; 13. The rotary atomizer (10) of claim 12.

[0095] [Appendix 14] The driver (23) projects axially distally from the clamp ring (19) and fits into a receptacle (24) in the hub portion (13) of the bell cup (1) so that when the bell cup (1) is rotated during assembly or disassembly, the clamp ring (19) also rotates. 14. The rotary atomizer (10) of claim 12 or 13.

[0096] [Appendix 15] a) In the assembled state of the bell cup (1), a predetermined axial clamping force (F AXIAL ) acts on the clamp ring (19), b) the inclined clamping surface (21) of the clamping ring (19) is in the assembled state such that the clamping element (F SPANN ) with a given surface normal clamping force (F SPANN ) and c) the clamping surface (21) of the clamping ring (19) is adapted to have a predetermined force transmission ratio of the axial clamping force (F AXIAL ) and on the other hand the surface-normal clamping force (F SPANN ) is inclined with respect to the rotation axis (2) of the bell cup (1), d) the force transmission ratio is at most 1:8 and / or is greater than 1:1, 1:2, 1:4 or 1:6; 15. The rotary atomizer (10) of any one of claims 12 to 14.

[0097] [Appendix 16] a) In the assembled state of the bell cup (1), a predetermined axial clamping force (F AXIAL ) acts on the clamp ring (19), b) in the threaded connection (20) between the clamping ring (19) and the hollow shaft (11), a certain friction force occurs which depends on the axial clamping force on the clamping ring (19); c) the friction force on the one hand and the axial clamping force (F AXIAL ) is at least 0.5:1, 1:1, or 1:2, and / or at most 1:6; 16. The rotary atomizer (10) of any one of claims 12 to 15.

[0098] [Appendix 17] a) said cage (17) comprises several sets of said clamping elements (18) distributed around its circumference; and / or b) the sets of clamping elements (18) are evenly distributed around the circumference; and / or c) the number of sets of clamping elements (18) is three; and / or d) the distance between the clamping elements (18) within a set is less than the distance between the clamping elements (18) of adjacent sets; and / or e) at least one of the clamping elements (18) is made of steel, ceramic, plastic or glass; and / or f) at least one of said clamping elements (18) has a diameter in the range of 1 mm-5 mm; and / or g) the number of clamping elements (18) is 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12; 17. A rotary atomizer (10) according to any one of claims 11 to 16.

[0099] [Appendix 18] a) at least one of the clamping elements (18) of the fixing arrangement (17-24) in the hollow shaft (11) of the rotary atomizer (10) on the one hand and the clamping surface (22) of the bell cup (1) on the other hand are made of different materials, b) at least one of the clamping elements (18) of the fixing arrangement (17-24) in the hollow shaft (11) of the rotary atomizer (10) is preferably made of ceramic; c) the clamping surface (22) of the bell cup (1) is made of steel, in particular hardened steel; 18. The rotary atomizer (10) of any one of claims 10 to 17.

[0100] [Appendix 19] a) the clamping connection between the inclined clamping surface (21) of the clamping ring (19) on the one hand and the clamping element (18) on the other hand is self-locking, and / or b) the clamp ring (19) has corrugated sections (32) in its longitudinal sections to render the clamp ring (19) resiliently flexible in the axial direction; 19. The rotary atomizer (10) of any one of claims 12 to 18.

[0101] [Appendix 20] a) the screw connections (20, 25) of said fixing arrangements are each right-hand threaded, in particular a1) the cage (17) and the hollow shaft (11) of said rotary atomizer (10); a2) the hub portion (13) and the spray body (3) of the bell cup, and / or a3) the hollow shaft (11) and the clamp ring (19) of the rotary sprayer (10); having a threaded connection between the parts, b) the rotary sprayer (10) is configured to rotate the hollow shaft (11) to the left during a coating operation, and the deceleration, and in particular the blocking of the rotational movement, of the hollow shaft (11) results in tightening of the right-hand thread of the threaded connection (20, 25); 20. A rotary sprayer according to any one of claims 9 to 19. [Explanation of symbols]

[0102] 1 Bell Cup 2 Bell cup rotation axis 3 Spray body of bell cup 4 Spray edge of bell cup 5. Dispersion disk holding portion of bell cup for holding dispersion disk 6 Bell Cup Dispersion Disc 7 Bell cup overflow surface 8 Outer surface of bell cup 9 Outer rinsing chamber of the bell cup 10 Rotary Sprayer 11 Hollow shaft of rotary sprayer 12 Centering cone of hollow shaft of rotary atomizer 13 Bell cup hub 14 Centering cone on hub of bell cup 15 Flat surface on hub of bell cup 16 Rotary sprayer hollow shaft end face 17 Ball cage for receiving clamp ball 18 Clamp Ball 19 Clamp ring 20 Threaded connection between the hollow shaft of the rotary sprayer and the clamp ring 21 Clamping surface of clamp ring 22 Clamping surface on hub 23 Driver on clamp ring 24 Receptacle in hub of bell cup for driver of clamp ring 25 Threaded connection between hub and bell cup spray body 26 Paint nozzle 27 Paint Channel 28 Outer rinse channel in bell cup 29 Outer rinse channel in bell cup 30 Section of the outer rinse channel between the hub and the spray body 31 Outer rinse channel outlet opening into the outer rinse chamber 32 Clamp Ring Wave Section F AXIAL Axial clamping force of the clamp ring F SPANN Radial clamping force of the clamping ball α Exit angle of the rinse fluid from the outer rinse channel into the outer rinse chamber

Claims

1. A bell cup (1) for a rotary atomizer (10) for spraying a coating agent, in particular a paint, comprising: a) a spray body (3) having an annular, circumferential spray edge (4) for spraying the coating agent; b) a hub portion (13) for mounting said bell cup (1) on the rotatable hollow shaft (11) of said rotary atomizer (10); c) a fixing arrangement (17-24) for matingly fixing the bell cup (1) to the hollow shaft (11) of the rotary atomizer (10); Equipped with d) the fixing arrangement (17-24) has on the outer surface of the hub portion (13) an annular, circumferential clamping surface (22) inclined with respect to the axis of rotation (2) of the bell cup (1) for abutment with a clamping element (18) of the rotary atomizer (10) in order to clamp the bell cup (1) on the hollow shaft (11) of the rotary atomizer (10) with an axial clamping force.

2. a) the hub portion (13) of the bell cup (1) includes an external centering cone (14) for abutment with a complementary shaped centering cone (12) in the hollow shaft (11) of the rotary atomizer (10); b) the centering cone (14) on the bell cup (1) is preferably tapered in the proximal direction; c) the centering cone (14) on the bell cup (1) is preferably coaxial with the axis of rotation (2) of the bell cup (1); A bell cup (1) according to claim 1.

3. a) the hub portion (13) of the bell cup (1) includes a flat surface (15) on the outside for abutment with the end face (16) of the hollow shaft (11) of the rotary atomizer (10), the flat surface (15) forming an axial stop; b) said flat surface (15) is preferably annular and circumferential with respect to the axis of rotation (2) of said bell cup (1); c) said flat surface (15) is preferably coaxial with the axis of rotation (2) of said bell cup (1); d) said flat surface (15) is preferably aligned essentially perpendicular to the axis of rotation (2) of said bell cup (1); e) said flat surface (15) is preferably axially adjacent to the centering cone (14); f) the flat surface (15) is preferably located axially between the centering cone (14) and the spray edge (4); A bell cup (1) according to claim 1.

4. The hub portion (13) of the bell cup (1) has a receptacle (24) for a driver (23) that projects axially from a clamp ring (19) in the hollow shaft (11) of the rotary atomizer (10) as a protrusion and, in an assembled state, projects axially into the receptacle in the hub portion (13) of the bell cup (1), so that when the bell cup (1) is rotated during assembly, it rotates the clamp ring (19). A bell cup (1) according to claim 1.

5. a) an outer peripheral surface (8) of the bell cup (1) that continues from the spray edge (4) and preferably widens in the spray direction, in particular conically; b) an outer rinsing chamber (9) for rinsing the outer peripheral surface (8) of the bell cup (1) with a rinsing agent, the outer rinsing chamber (9) being located behind the bell cup (1) and preferably having an annular shape; c) at least one outer rinsing channel (29, 30) for supplying said rinsing agent, starting from a rinsing agent supply inside said bell cup (1) and opening into said outer rinsing chamber (9) at an outlet opening (31); Equipped with d) the hub part (13) and the spray body (3) are separate parts connected to each other, in particular by a threaded connection of the hub part (13) to the spray body (3), in particular by an internal thread on the hub part (13) and an external thread on the spray body (3); e) the outer rinse channel (29, 30) extends over a section (30) of the length of the outer rinse channel (29, 30) between the hub portion (13) and the spray body (3), in particular before the outlet opening (31) of the outer rinse channel (29, 30) into the outer rinse chamber (9); f) the outer rinse channels (29, 30) in the section (30) between the hub portion (13) and the spray body (3) are preferably annular channels running around the entire circumference; A bell cup (1) according to claim 1.

6. a) the outer rinse channels (29, 30) form a deflection in the section (30) between the hub portion (13) and the spray body (3) with a change in the direction of flow of the rinse agent in the outer rinse channels (29, 30); b) the rinsing agent in the outer rinsing channels (29, 30) upstream of the outlet opening (31) of the outer rinsing channel preferably flows in a distal direction; c) the rinsing agent is released from the outlet opening (31) of the outer rinsing channel, preferably in a proximal direction, into the outer rinsing chamber (9); Bell cup (1) according to claim 5.

7. a) the flow of rinsing agent exiting the outlet opening (31) of the outer rinsing channel and entering the outer rinsing chamber (9) is aligned essentially parallel to the axis of rotation (2) of the bell cup (1), in particular within a tolerance range of ±10°, ±5° or ±2°, or b) the flow of rinsing agent leaving the outlet opening (31) of the outer rinsing channel and entering the outer rinsing chamber (9) is inclined outwards, in particular with a tolerance range of ±10°, ±5° or ±2°, in particular with an outlet angle (α) of 15° with the rotation axis (2) of the bell cup (1), or c) the flow of rinsing agent leaving the outlet opening (31) of the outer rinsing channel and entering the outer rinsing chamber (9) is inclined inwards, in particular with a tolerance range of ±10°, ±5° or ±2°, in particular with an outlet angle (α) of at least 15°, 20° or 25° with the rotation axis (2) of the bell cup (1); Bell cup (1) according to claim 6.

8. a) the spray body (3) and the hub portion (13) are integral and together form a single part, or b) the spray body (3) and the hub part (13) are separate parts connected to each other, in particular by a threaded connection (25) of the hub part (13) to the spray body (3), in particular by an internal thread on the hub part (13) and an external thread on the spray body (3); A bell cup (1) according to claim 1.

9. A rotary atomizer (10) for spraying a coating material, in particular a paint, comprising: a) a rotatably mounted hollow shaft (11) for rotating a bell cup (1), in particular a bell cup (1) according to any one of claims 1 to 8; b) a fixing arrangement (17-24) for matingly fixing the bell cup (1) to the hollow shaft (11) of the rotary atomizer (10); and c) the fixing arrangement (17-24) comprises at least one clamping element (18) in the hollow shaft (11) of the rotary sprayer (10) for abutment with a clamping surface (22) of the bell cup (1) in order to clamp the bell cup (1) on the hollow shaft (11) of the rotary sprayer (10) with an axial clamping force.

10. a) at least one of said clamping elements (18) is a rolling element, in particular a clamping ball (18), and / or b) the clamping element (18) has a radial range of motion within the hollow shaft (11) of the rotary atomizer (10); and / or c) the clamping element (18) in its radially inner clamping position clamps the bell cup (1) onto the hollow shaft (11) of the rotary atomizer (10), and / or d) the clamping elements (18) in their radially outer open position open the bell cup (1) to allow assembly or disassembly of the bell cup (1); A rotary atomizer (10) according to claim 9.

11. a) a cage (17) is provided for radially movably retaining the clamping element (18) within the hollow shaft (11) of the rotary atomizer (10); b) the cage (17) is arranged in the hollow shaft (11) of the rotary atomizer (10) together with the clamping element (18); c) said cage (17) is preferably substantially hollow cylindrical in shape; d) the cage (17) is preferably screwed with an external thread into the internal thread of the hollow shaft (11) of the rotary atomizer (10); A rotary atomizer (10) according to claim 10.

12. a) a clamping ring (19) is provided for moving the clamping element (18) from the outer, open position to the inner, clamped position; b) the clamping ring (19) is located in the annular gap between the cage (17) and the hollow shaft (11) of the rotary atomizer (10); c) the clamping ring (19) is connected to the hollow shaft (11) of the rotary sprayer (10) by a threaded connection (20) having an external thread on the clamping ring (19) and an internal thread in the hollow shaft (11) of the rotary sprayer (10), so that rotation of the clamping ring (19) results in a corresponding axial displacement of the clamping ring (19) within the hollow shaft (11) of the rotary sprayer (10); d) the clamping ring (19) has a clamping surface (21) at its proximal end that is inclined with respect to the rotation axis (2) of the bell cup (1) and that widens in the proximal direction, so that the clamping ring (19) pushes the clamping elements (18) radially inwardly into the clamped position when moving in the proximal direction; A rotary atomizer (10) according to claim 11.

13. the clamping elements (18) are pressed outward against the clamping surface of the clamping ring (19) due to the centrifugal forces generated when the hollow shaft (11) rotates during a coating operation, thereby axially fixing the threaded connection (20) between the clamping ring (19) and the hollow shaft (11) of the rotary atomizer (10), so that the frictional forces in the threaded connection (20) between the clamping ring (19) and the hollow shaft (11) increase with the rotational speed. A rotary atomizer (10) according to claim 12.

14. A driver (23) protrudes axially distally from the clamp ring (19) and fits into a receptacle (24) in the hub portion (13) of the bell cup (1), so that when the bell cup (1) is rotated during assembly or disassembly, the clamp ring (19) also rotates. A rotary atomizer (10) according to claim 12.

15. a) In the assembled state of the bell cup (1), a predetermined axial clamping force (F ＡＸＩＡＬ ) acts on the clamp ring (19), b) the inclined clamping surface (21) of the clamping ring (19) is in the assembled state such that the clamping element (F ＳＰＡＮＮ ) to a predetermined surface normal clamping force (F ＳＰＡＮＮ ) and c) the clamping surface (21) of the clamping ring (19) is such that a predetermined force transmission ratio is established between the axial clamping force (F) on the clamping ring (19) and the ＡＸＩＡＬ ) on the other hand, the surface-normal clamping force (F ＳＰＡＮＮ ) and is inclined with respect to the rotation axis (2) of the bell cup (1) so as to occur between d) the force transmission ratio is at most 1:8 and / or is greater than 1:1, 1:2, 1:4 or 1:6; A rotary atomizer (10) according to claim 12.

16. a) In the assembled state of the bell cup (1), a predetermined axial clamping force (F ＡＸＩＡＬ ) acts on the clamp ring (19), b) in the threaded connection (20) between the clamping ring (19) and the hollow shaft (11), a predetermined friction force occurs which depends on the axial clamping force on the clamping ring (19); c) the friction force on the one hand and the axial clamping force (F ＡＸＩＡＬ ) is at least 0.5:1, 1:1, or 1:2, and / or at most 1:6; A rotary atomizer (10) according to claim 12.

17. a) said cage (17) comprises several sets of said clamping elements (18) distributed around its circumference, and / or b) the sets of clamping elements (18) are evenly distributed around the circumference, and / or c) the number of sets of clamping elements (18) is three, and / or d) the distance between the clamping elements (18) within a set is less than the distance between the clamping elements (18) of adjacent sets; and / or e) at least one of said clamping elements (18) is made of steel, ceramic, plastic or glass, and / or f) at least one of said clamping elements (18) has a diameter in the range of 1 mm-5 mm; and / or g) the number of said clamping elements (18) is 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12; A rotary atomizer (10) according to claim 11.

18. a) at least one of the clamping elements (18) of the fixing arrangement (17-24) in the hollow shaft (11) of the rotary atomizer (10) on the one hand and the clamping surface (22) of the bell cup (1) on the other hand are made of different materials; b) at least one of the clamping elements (18) of the fixing arrangement (17-24) in the hollow shaft (11) of the rotary atomizer (10) is preferably made of ceramic; c) the clamping surface (22) of the bell cup (1) is made of steel, in particular hardened steel; A rotary atomizer (10) according to claim 10.

19. a) the clamping connection between the inclined clamping surface (21) of the clamping ring (19) on the one hand and the clamping element (18) on the other hand is self-locking; and / or b) the clamping ring (19) has corrugated sections (32) in its longitudinal sections to make the clamping ring (19) resiliently flexible in the axial direction; A rotary atomizer (10) according to claim 12.

20. a) the threaded connections (20, 25) of said fixing arrangements are each right-hand threaded, in particular a1) the cage (17) and the hollow shaft (11) of said rotary atomizer (10); a2) the hub portion (13) and the spray body (3) of said bell cup, and / or a3) the hollow shaft (11) and clamp ring (19) of the rotary atomizer (10); having a threaded connection between the parts, b) the rotary atomizer (10) is configured to rotate the hollow shaft (11) to the left during the coating operation, and the slowing down, in particular the blocking of the rotational movement, of the hollow shaft (11) results in tightening of the right-hand thread of the threaded connection (20, 25); 10. The rotary atomizer of claim 9.

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