Drive turbine for rotary atomizer

Abstract

The invention relates to a drive turbine (2) for a rotary atomizer (1), comprising a turbine rotor with a rotatably mounted turbine shaft (5). According to the invention, the turbine shaft (5) is stepped along the axis of rotation (6) thereof with different shaft diameters (D1, D2, D4), in particular with different inner diameters (D2) and / or different outer diameters (D1, D4).

Description

Technical Field

[0001] The invention relates to a drive turbine for a rotary atomizer, in particular for painting motor vehicle body parts in a painting plant, and also to a rotary atomizer having such a drive turbine according to the invention. Background Art

[0002] In modern painting facilities for painting car body parts, a rotary atomizer is usually used as the application device, which is driven by a drive turbine by compressed air. The drive turbine has a turbine shaft, and a bell cup is mounted at the distal end of the turbine shaft, for example by a threaded connection between the turbine shaft and the bell cup. During the painting operation, the turbine shaft rotates at a high speed, and the bell cup is mounted thereon, so that the bell cup rotates and atomizes the paint to be applied from the annular spray edge. The paint is usually delivered to the bell cup by a paint pipe, which is arranged in the hollow turbine shaft and contains one or two main needle valves for opening or closing the application of the paint as required.

[0003] With these known rotary atomizers, there is a design conflict regarding the diameter of the turbine shaft.

[0004] On the one hand, a maximum inner diameter of the hollow turbine shaft is required so that there is enough space inside the turbine shaft to accommodate a paint tube with a plurality of main needle valves.

[0005] On the other hand, a large diameter of the turbine shaft leads to a correspondingly large moment of inertia, which requires a correspondingly large drive power. In addition, a large diameter of the turbine shaft also leads to a correspondingly large centrifugal load and an increase in the turbine shaft speed induced by the correspondingly large centrifugal force, which is undesirable.

[0006] Regarding the technical background of the present invention, reference should also be made to WO2015 / 029763A1, US2005 / 0001057A1, EP0645191B1, EP1245290B1 and DE102010013551A1. Summary of the invention

[0007] The present invention is therefore based on the task of resolving the above-mentioned design conflicts.

[0008] This object is achieved by a drive turbine according to the main claim.

[0009] The drive turbine according to the invention is designed for driving a rotary atomizer, as is known from the prior art. It should be mentioned here that the drive turbine according to the invention comprises a turbine rotor with a rotatably mounted turbine shaft, as has already been briefly described above with respect to the prior art. The invention solves the initially described design conflict by designing the turbine shaft to be stepped along its axis of rotation with different shaft diameters, in particular different inner diameters and / or different outer diameters. Therefore, in the drive turbine according to the invention, the diameter of the turbine shaft is not constant along its axis of rotation. Statements about different diameters of the turbine shaft preferably refer to the turbine shaft region axially before and after the wheel of the turbine rotor, since the wheel naturally has a larger outer diameter than the rest of the turbine shaft. Therefore, if the wheel is ignored, the turbine shaft according to the invention also preferably has different diameters.

[0010] In a preferred embodiment of the invention, the turbine shaft comprises a proximal shaft section with a larger shaft diameter and a distal shaft section with a smaller shaft diameter. Within the scope of the invention, this can apply to the inner diameter of the turbine shaft and / or the outer diameter of the turbine shaft. Thus, the larger shaft diameter of the proximal shaft section makes it possible to accommodate a paint tube with multiple (for example three or four) main needle valves, although in the context of the present invention, it is of course also possible to arrange only one main needle valve in the paint tube. On the other hand, the smaller shaft diameter of the distal shaft section ensures that the moment of inertia and the requirements for drive power are not too large. In this way, the drive turbine according to the invention solves the design conflict mentioned at the beginning.

[0011] In a preferred embodiment of the present invention, the turbine shaft has a predetermined outer diameter at the proximal shaft portion, wherein the turbine shaft preferably carries at least one wheel with a plurality of turbine blades and / or comprises a paint tube with a predetermined paint tube outer diameter at the proximal shaft portion.

[0012] The turbine shaft for receiving the paint tube is preferably hollow and has a specific inner diameter in the proximal shaft section, and the inner diameter of the turbine shaft in the proximal shaft section is preferably in the range of 25mm to 35mm, and the range from 28mm to 32mm has proved to be particularly advantageous. In a preferred embodiment of the present invention, the inner diameter of the turbine shaft in the proximal shaft section is 30.5mm, and a deviation of ±0.5mm is possible.

[0013] Furthermore, it should be mentioned that the drive turbine in the preferred embodiment has at least one annular shaping air nozzle ring with a plurality of shaping air nozzles, wherein each shaping air nozzle can eject a jet of shaping air in order to shape the paint spray jet applied by the bell cup. This technique of shaping the paint spray jet by blowing shaping air onto the back of the spray jet is known per se and is part of general technical knowledge, so that no separate description is required in this regard. However, it should be noted here that the shaping air nozzle ring has a specific diameter.

[0014] It should also be mentioned that the turbine shaft has a certain outer diameter at the distal shaft section and preferably has a mounting interface for mounting a bell cup on the turbine shaft. For example, the bell cup can be mounted on the turbine shaft by threaded connection, but other types of mounting can also be realized within the scope of the invention.

[0015] In a preferred embodiment of the invention, the drive turbine is characterized in that the turbine shaft has a certain diameter ratio, as described below.

[0016] Therefore, the outer diameter of the turbine shaft in the proximal shaft section is preferably greater than the outer diameter of the turbine shaft in the distal shaft section. This advantageously achieves a combination of maximum installation space for the proximal shaft section in the hollow turbine shaft and minimum mass moment of inertia of the turbine shaft.

[0017] Here, the ratio between the outer diameter of the turbine shaft in the proximal shaft section and the outer diameter of the turbine shaft in the distal shaft section can preferably be in the range of 1.1:1 to 1.6:1, for example a ratio in the range of 1.3:1 to 1.4:1 has proven to be particularly advantageous.

[0018] It should also be mentioned that the inner diameter of the turbine shaft in the proximal shaft section is preferably greater than the outer diameter of the turbine shaft in the distal shaft section. This also advantageously achieves a combination of maximum installation space of the proximal shaft section in the hollow turbine shaft and minimum mass inertia moment of the turbine shaft.

[0019] Here, the ratio between the inner diameter of the turbine shaft in the proximal shaft section and the outer diameter of the turbine shaft in the distal shaft section can preferably be in the range of 1.05:1 to 1.4:1, a ratio in the range of 1.1:1 to 1.2:1 having proven to be particularly advantageous.

[0020] It should also be noted that the diameter of the shaping air nozzle ring is preferably larger than the outer diameter of the turbine shaft in the distal shaft section.

[0021] Here, the ratio between the diameter of the shaping air nozzle ring and the outer diameter of the turbine shaft in the distal shaft section can preferably be in the range of 1.1:1 to 1.9:1, and ratio values ​​in the range of 1.3:1 to 1.7:1 have proven to be particularly advantageous in order to discharge the shaping air at the minimum radial distance from the axis of rotation of the turbine shaft in order to achieve an optimal consumption of the shaping air. If the shaping air is discharged at a greater radial distance from the axis of rotation of the turbine shaft, then correspondingly more shaping air must be discharged, so that the shaping air nozzles should be as close to the axis of rotation as possible.

[0022] In a preferred embodiment of the invention, the drive turbine has a radial bearing which is located in the proximal shaft section of the shaft turbine and extends axially over a certain bearing section. Therefore, the bearing section is preferably completely located in the proximal shaft section with a larger shaft diameter. For example, such a radial bearing can be designed as an air bearing (aerostatic or aerodynamic bearing). In this case, in order to achieve a low moment of inertia of the turbine shaft, there can be a certain ratio between the outer diameter of the turbine shaft in the bearing section and the inner diameter of the turbine shaft in the bearing section. In a preferred embodiment, this ratio is a maximum of 1.3:1, 1.2:1 or 1.15:1.

[0023] It has been mentioned above that the turbine shaft is preferably hollow and can accommodate a paint tube inside, which has a specific outer diameter of the paint tube. Preferably, the ratio between the inner diameter of the turbine shaft in the proximal shaft section and the outer diameter of the paint tube is preferably in the range of 1.005:1 to 1.5:1, and a ratio in the range of 1.01:1 to 1.3:1 has proven to be advantageous in order to achieve a suitable pressure gradient.

[0024] In addition, the drive turbine preferably also includes an axial bearing with a rotating bearing disk, which is used to mount the turbine shaft. For example, the axial bearing can also be designed as an air bearing (air static pressure or air dynamic pressure bearing). In addition, the drive turbine according to the present invention preferably has a speed sensor, which has a rotating sensor disk for speed detection, as known from WO2022 / 157098A1 itself. In addition, the drive turbine includes a wheel with multiple turbine blades, which is used to accelerate or decelerate the turbine rotor. Within the scope of the present invention, the bearing disk, the sensor disk and the wheel can be integrated into one component. Integrating multiple functions (bearing disk, sensor disk and wheel) into one component can reduce the complexity of the drive turbine.

[0025] It has been mentioned above that the axial bearing and the radial bearing can be defined as air bearings, which exhaust axial bearing exhaust and radial bearing exhaust during operation. It should also be mentioned that the drive turbine is driven by drive air during operation and exhausts turbine exhaust.

[0026] In the drive turbine according to the present invention, it is preferably configured that the radial bearing exhaust in the drive turbine is at least partially combined with the turbine exhaust to increase the temperature of the turbine exhaust, thereby avoiding condensation. For example, the radial bearing exhaust can be combined with the turbine exhaust in a ratio of 35%-75%.

[0027] In addition, it is also advantageous to combine the axial bearing exhaust in the driving turbine at least partially with the turbine exhaust to increase the temperature of the turbine exhaust and thus avoid condensation in the driving turbine. For example, the axial bearing exhaust can be combined with the turbine exhaust in a ratio of 25%-65%.

[0028] It has already been briefly mentioned above that the turbine rotor comprises a wheel with a plurality of turbine blades, which during operation are blown by at least one drive air nozzle with drive air in order to drive the drive turbine. In addition, preferably a plurality of brake air nozzles are provided for blowing air against the direction of rotation of the drive turbine blades in order to be able to brake the turbine rotor. The brake air nozzles are preferably distributed around the circumference of the wheel. It should be noted here that each brake air nozzle can flow to at least two or at least three turbine blades at different flow angles, respectively. The turbine blades are preferably all of the same design, i.e. no separate, differently shaped turbine blades are provided for braking the drive turbine.

[0029] When painting vehicle body parts, electrostatic paint charging is often performed in order to increase the efficiency of the application and to minimize disturbing overspray. Against the background of such electrostatic paint charging, it can be provided in the context of the present invention that the drive turbine has a discharge device for discharging the potential from the turbine shaft. The discharge device preferably forms a discharge path to ground, the discharge path preferably having a resistance of less than 10 kΩ.

[0030] The discharge path preferably contacts the turbine shaft at its distal shaft section, in particular at an axial distance of less than 5 cm, 3 cm, 2 cm or 1 cm from the distal end of the turbine shaft. Such electrical contacting of the turbine shaft at its distal end is advantageous because the discharge path then passes through only a small portion of the turbine rotor and is therefore relatively short.

[0031] In a preferred embodiment of the present invention, the discharge device surrounds the turbine shaft in an annular form in the axial direction between the radial bearing and the distal end of the turbine shaft. In this case, the discharge device can also form a sealing structure to seal the radial bearing relative to the environment. For example, the discharge device can have an electrical contact brush or foil for electrical contact with the turbine shaft.

[0032] It has already been mentioned above that the turbine shaft is preferably rotatably mounted in at least one radial bearing, which extends in the axial direction over a specific bearing segment located within the proximal shaft segment of the turbine shaft. The radial bearing has a specific bearing clearance in the radial direction. It is advantageous if the ratio between the axial length of the bearing segment and the radial bearing clearance of the radial bearing is in the range of 1000:1 to 8000:1, values ​​in the range of 2000:1 to 6000:1 have proven to be particularly advantageous in order to achieve sufficient stability and low bearing loss properties of the radial bearing.

[0033] Within the scope of the present invention, a plurality of main valves can be accommodated in the hollow turbine shaft to control the delivery of the coating agent of the rotary atomizer. The term "main valve" used in the context of the present invention means that, according to the meaning of the term in technical terms, there is no additional valve downstream of the corresponding main valve. Therefore, the main valve is used to open or close the application of the coating. The stepped shape of the turbine shaft makes it possible to arrange more than two, three or even more than four main valves in the hollow turbine shaft. For example, a total of four main valves can be arranged in the hollow turbine shaft. It should be mentioned here that each main valve is preferably designed as a needle valve, each needle valve has a movable valve needle, which can open or close the valve seat according to its position, thereby opening or closing the delivery of the coating.

[0034] In a preferred embodiment of the present invention, the turbine shaft has only two different shaft diameters, namely a larger shaft diameter of the proximal shaft section and a smaller shaft diameter of the distal shaft section.

[0035] It should also be mentioned that in a preferred embodiment of the invention the drive turbine has a turbine housing, wherein the turbine shaft protrudes with its distal shaft section in the axial direction from the turbine housing so that the bell cup can be mounted on the turbine shaft.

[0036] For example, the bell cup may be mounted on the distal end of the turbine shaft by a threaded connection, as is known in the art. However, other types of fastening are also possible within the scope of the invention.

[0037] As explained above, the turbine shaft has different diameters. It should be mentioned here that the transition between the different diameters of the turbine shaft preferably occurs abruptly. However, the transition between the different shaft diameters of the turbine shaft may also be continuous, ie not abrupt.

[0038] Furthermore, it should generally be mentioned that the drive turbine can be an axial turbine or a radial turbine. However, within the scope of the invention, a combination of axial turbines and radial turbines is also possible.

[0039] It should also be noted that the present invention not only claims protection for the above-mentioned drive turbine according to the present invention. Further, the invention also claims protection for a complete rotary atomizer having such a drive turbine. Finally, the present invention also claims protection for a turbine shaft for a drive turbine of a rotary atomizer, wherein the turbine shaft is stepped along its axis of rotation with different shaft diameters, as described above. Therefore, the turbine shaft according to the present invention can also have the above-mentioned features for the entire drive turbine as a replacement part or as a single part.

[0040] Advantages of the invention

[0041] The present invention has the following advantages in particular:

[0042] - Space for four main needle valves is provided in the turbine shaft.

[0043] The drive turbine according to the invention has relatively small dimensions.

[0044] - Weight reduction by integrating multiple functions (bearing disc, sensor disc and turbine) into one component.

[0045] -Optimized bearing air guidance.

[0046] -Improved braking performance.

[0047] -Better high voltage discharge.

[0048] - Improved stability and robustness against imbalance.

[0049] Further advantageous embodiments of the invention are stated in the dependent claims or are explained in more detail below in the description of preferred embodiments of the invention in conjunction with the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 An external view of a rotary atomizer according to the invention is shown.

[0051] Figure 2 Shows Figure 1 Cross-section of the drive turbine of the rotary atomizer.

[0052] Figure 3 Shows Figure 2 Another cutaway view of the mid-drive turbine.

[0053] Figure 4A A perspective view of a wheel having a plurality of turbine blades driving a turbine is shown.

[0054] Figure 4B Shows Figure 4A Another perspective of the wheel in the.

[0055] Figure 4C Shows Figure 4A and 4B Side view of the wheel.

[0056] Figure 5 Shows Figure 2 An enlarged view of the turbine exhaust is shown to illustrate the flow path of the turbine exhaust.

[0057] Figure 6 A section through a drive turbine is shown, wherein a plurality of brake air nozzles are schematically illustrated.

[0058] Figure 7 A cross-sectional view of a discharge device for discharging electrostatic potential is shown. DETAILED DESCRIPTION

[0059] The following is an explanation of an embodiment of the rotary atomizer 1 of the present invention shown in the accompanying drawings, which can be used for painting car body parts in a painting plant. It should be mentioned here that the rotary atomizer 1 is usually guided by a multi-axis painting robot, but for the sake of simplicity, this is not shown.

[0060] A rotary atomizer 1 having a drive turbine 2 which rotates a bell cup 3 at high speed during the painting operation is known from the prior art.

[0061] In the present case, the bell cup 3 is mounted on the distal shaft section 4 of the rotatably mounted turbine shaft 5 by means of a threaded connection, which is also known per se in the prior art. However, it should be mentioned here that the bell cup 3 does not necessarily have to be mounted on the turbine shaft 5 by means of a threaded connection, since other types of fastening (e.g. clamping connections) are also possible within the scope of the invention. The turbine shaft 5 with the bell cup 3 is then rotated about the axis of rotation 6 during the coating operation.

[0062] The turbine shaft 5 is hollow and provides space in its interior for a paint pipe 7 which is only schematically shown here and may contain a plurality of main needle valves, which will be described in detail below.

[0063] As is known in the prior art, the drive turbine 2 further comprises a rear casing segment 8 and a front casing segment 9 .

[0064] A radial bearing 10 is arranged in the front housing section 9 , which is designed as an air bearing and extends in the bearing direction over a bearing section 11 .

[0065] Furthermore, it should be mentioned that the turbine shaft 5 carries in the proximal shaft section 12 a wheel having a plurality of turbine blades 14, in particular from Figures 4A-4C It can be seen that the turbine blades 14 are only shown schematically here.

[0066] The wheel 13 is surrounded on its circumference by a nozzle ring 15 having a plurality of circumferentially distributed drive air nozzles for blowing air towards the turbine blades 14 of the wheel 13, as is known from EP1388372B1 itself, and therefore the contents of this patent concerning the design of the drive turbine 2 should be incorporated herein by reference as a whole.

[0067] The wheel 13 and the nozzle ring 15 are adjacent to a further fixed ring 16, which contains an exhaust duct 17 for receiving the turbine exhaust. The exhaust duct 17 in the fixed ring 16 then finally leads to a common exhaust duct 18, which also receives radial bearing exhaust from the radial bearing 10, such as Figure 3 The mixing of the radial bearing exhaust gas with the turbine exhaust gas increases the exhaust gas temperature at the turbine outlet, thereby preventing condensation inside the drive turbine 2.

[0068] It should also be mentioned that the wheel 13 is also part of the axial bearing, which also discharges axial bearing exhaust, which is also discharged into the common exhaust duct 18, such as Figure 3 This also increases the exhaust gas temperature at the turbine outlet, thereby preventing condensation inside the drive turbine 2.

[0069] also, Figure 2 It is shown that the drive turbine 2 has a shaping air nozzle ring, on the end face of which there are a plurality of shaping air nozzles 19, which are distributed in the circumferential direction and each nozzle ejects a shaping air jet 20. By ejecting the shaping air jet 20, the paint spray jet ejected from the bell cup 3 can be shaped, as is known in the prior art.

[0070] The shaping air is supplied via a shaping air duct 21, wherein the shaping air duct 21 is fed by shaping air from an air space 22. The air space 22 is located between the front housing segment 9 of the drive turbine 2 and an annular housing cover 23. The supply of shaping air from the air space 22 is also described in a similar form in EP1384514B1, the content of which should therefore be incorporated herein by reference in its entirety.

[0071] It should also be mentioned that the wheel 13 driving the turbine 2 comprises an annular magnetic encoder 24 which enables magnetic speed measurement, as is known from WO 2022 / 157098 A1 itself, and therefore the contents concerning speed measurement in that patent should be incorporated herein by reference in their entirety.

[0072] It should be mentioned here that the wheel 13 performs three technical functions. Firstly, the wheel 13 realizes the mechanical drive of the turbine shaft 5 by blowing air to the turbine blades 14. Secondly, the wheel 13 can also perform speed measurement via the annular magnetic encoder 24. Finally, the wheel 13 also forms part of the axial bearing of the drive turbine 2. The integration of three technical functions in the wheel 13 is advantageous because the number of required components can be reduced.

[0073] In the present embodiment, the shaft diameter of the turbine shaft 5 along the axis of rotation 6 is not uniform. Instead, the outer diameter D1 of the turbine shaft 5 in the proximal shaft section 12 is greater than the outer diameter D4 of the turbine shaft 5 in the distal shaft section 4. The ratio D1:D4 is preferably in the range of 1.3:1 to 1.4:1. This is advantageous in combining the maximum installation space in the turbine shaft 5 with the minimum mass moment of inertia of the turbine shaft 5. The installation space in the hollow turbine shaft 5 is so large that the paint tube 7 can be designed to be correspondingly large so that a total of four main needle valves can be accommodated.

[0074] Furthermore, it should be mentioned that the inner diameter D2 of the turbine shaft 5 in the proximal shaft section 12 is also greater than the outer diameter D4 of the turbine shaft 5 in the distal shaft section 4. Therefore, the ratio D2:D4 is preferably in the range of 1.1:1 to 1.2:1. As mentioned above, this is advantageous in combining a maximum installation space in the turbine shaft 5 with a minimum mass moment of inertia of the turbine shaft 5.

[0075] The diameter D3 of the shaping air nozzle ring with the shaping air nozzles 19 is preferably greater than the outer diameter D4 of the turbine shaft 5 in the distal shaft section 4. The ratio D3:D4 is preferably in the range of 1.7:1 to 1.3:1. This is advantageous for achieving a consumption-optimized shaping air supply at a short distance from the axis of rotation 6 of the turbine shaft 5. When shaping air is supplied from a longer radial distance from the axis of rotation 6 of the turbine shaft 5, correspondingly more shaping air must be supplied, so that the shaping air nozzles 19 should be as close to the axis of rotation 6 as possible.

[0076] It should also be mentioned that the coating tube 7 in the hollow turbine shaft 5 has an outer diameter D5 which is smaller than the inner diameter D2 of the turbine shaft 5. The ratio D2:D5 is preferably in the range of 1.01:1 to 1.3:1 to generate a suitable pressure gradient.

[0077] Figure 3 It is also shown that the radial bearing exhaust gas enters the common exhaust gas duct 18 directly through the exhaust gas duct 25. Therefore, the common exhaust gas duct 18 sucks in the radial bearing exhaust gas, the axial bearing exhaust gas and the turbine exhaust gas.

[0078] from Figure 6 It can also be seen that a plurality of brake air nozzles 26, 27, 28 are provided, which are only shown schematically here, and which are used to brake the drive turbine 2 by blowing brake air against the drive direction onto the turbine blades 14. It has proven to be advantageous that the brake air nozzles 26-28 blow brake air onto a plurality of turbine blades 14 at different flow angles, respectively.

[0079] at last, Figure 7 A discharge device is shown for discharging electrostatic potential from the turbine shaft 5, which is advantageous in the case of electrostatic paint charging.

[0080] For this purpose, the discharge device has an annular discharge device 29 which may include a contact brush and rest against the outer surface of the turbine shaft 5 and may also form a sealing structure. The discharge device 29 is connected to the ground potential GND via a discharge path 30, wherein the resistance R of the discharge path 30 is less than 10 kΩ.

[0081] The invention is not limited to the preferred embodiments described above. On the contrary, a large number of variants and modifications are possible, which also exploit the inventive concept and therefore fall within the scope of protection herein. In particular, the invention also claims protection for the features of the subject matter and dependent claims, independently of the features and claims mentioned. The invention therefore comprises various aspects of the invention which enjoy protection independently of one another. This applies in particular to ideas relating to the discharge device, the size of the bearing gap, the brake airflow and the merging of the bearing exhaust with the turbine exhaust.

[0082] Reference numerals list

[0083] 1 Rotary Atomizer

[0084] 2 Driving turbine of rotary atomizer

[0085] 3. Bell Cup

[0086] 4 Distal end of turbine shaft

[0087] 5 Turbine shaft

[0088] 6 Turbine shaft axis of rotation

[0089] 7 Paint pipe in turbine shaft

[0090] 8 Rear casing section driving the turbine

[0091] 9 Front casing section of the drive turbine

[0092] 10Radial bearing for installing turbine shaft

[0093] 11 Bearing segment of radial bearing

[0094] 12 Proximal end section of turbine shaft

[0095] 13 Turbine rotor wheels

[0096] 14 turbine blades of the turbine rotor wheel

[0097] 15 Nozzle ring with drive air nozzles for blowing air to the turbine blades of the wheel

[0098] 16Fixed ring

[0099] 17 Exhaust duct

[0100] 18 Exhaust pipe

[0101] 19 Shaping air nozzle

[0102] 20Shaped air jet

[0103] 21Forming air duct

[0104] 22 Air space for forming air ducts

[0105] 23 Housing cover for covering the air space

[0106] 24 Ring magnetic encoder for speed measurement of turbine wheel,

[0107] 25 Exhaust duct

[0108] 26-28 Brake air nozzles for blowing air to the turbine blades of the wheels

[0109] 29 discharge device

[0110] 30 Discharge path of discharge device

[0111] GND ground potential

[0112] D1 The outer diameter of the turbine shaft at the proximal end

[0113] D2 Inner diameter of turbine shaft at proximal end

[0114] D3 Diameter of the shaping air nozzle ring

[0115] D4 The outer diameter of the turbine shaft at the distal end

[0116] D5 The outer diameter of the paint tube in the turbine shaft

[0117] RDischarge path resistance to ground

Claims

1. A driving turbine (2) for a rotary atomizer (1), comprising: a) a turbine rotor having a rotatably mounted turbine shaft (5), It is characterized in that b) The turbine shaft (5) is stepped along its axis of rotation (6) with different shaft diameters (D1, D2, D4), in particular with different inner diameters (D2) and / or different outer diameters (D1, D4).

2. The drive turbine (2) according to claim 1, characterized in that The turbine shaft (5) has a larger shaft diameter (D1, D2), in particular a larger inner diameter (D2) and / or a larger outer diameter (D1), in a proximal shaft section (12) than in a distal shaft section (4).

3. The drive turbine (2) according to claim 2, characterized in that a) The turbine shaft (5) has a specific outer diameter (D1) in the proximal shaft section (12), wherein the turbine shaft (5) in the proximal shaft section (12) preferably: a1) carries at least one wheel (13) having a plurality of turbine blades (14), and / or a2) comprising a coating tube (7) having a specific coating tube outer diameter (D5), b) the turbine shaft (5) for receiving the coating material tube (7) of the rotary atomizer is hollow and has a specific inner diameter (D2) in the proximal shaft section (12), the inner diameter (D2) in the proximal shaft section (12) is preferably in the range of 25 mm to 35 mm, in particular in the range of 28 mm to 32 mm, in particular the inner diameter is 30.5 mm ± 0.5 mm, c) the drive turbine (2) comprises at least one annular shaping air nozzle ring with a plurality of shaping air nozzles (19), the shaping air nozzle ring having a specific diameter (D3), and / or d) The turbine shaft (5) has a specific outer diameter (D4) in the distal shaft section (4) and preferably has a mounting interface, in particular a threaded portion, in order to mount the bell cup (3) on the turbine shaft (5).

4. The drive turbine (2) according to claim 3, characterized in that a) the outer diameter (D1) of the turbine shaft (5) in the proximal shaft section (12) is greater than the outer diameter (D4) of the turbine shaft (5) in the distal shaft section (4) in order to preferably combine a maximum installation space in the proximal shaft section (12) with a minimum mass moment of inertia of the turbine shaft (5), and / or b) a ratio between an outer diameter (D1) of the turbine shaft (5) in the proximal shaft section (12) and an outer diameter (D4) of the turbine shaft (5) in the distal shaft section (4) is in the range of 1.1:1 to 1.6:1, in particular in the range of 1.3:1 to 1.4:

1.

5. The drive turbine (2) according to claim 3 or 4, characterized in that a) the inner diameter (D2) of the turbine shaft (5) in the proximal shaft section (12) is greater than the outer diameter (D4) of the turbine shaft (5) in the distal shaft section (4), in order to preferably combine a maximum installation space in the proximal shaft section (12) with a minimum mass moment of inertia of the turbine shaft (5), and / or b) a ratio between an inner diameter (D2) of the turbine shaft (5) in the proximal shaft section (12) and an outer diameter (D4) of the turbine shaft (5) in the distal shaft section (4) is in the range of 1.05:1 to 1.4:1, in particular in the range of 1.1:1 to 1.2:

1.

6. The drive turbine (2) according to any one of claims 3 to 5, characterized in that a) the diameter (D3) of the shaping air nozzle ring is greater than the outer diameter (D4) of the turbine shaft (5) in the distal shaft section (4), and / or b) The ratio between the diameter (D3) of the shaping air nozzle ring and the outer diameter (D4) of the turbine shaft (5) in the distal shaft section (4) is in the range of 1.1:1 to 1.9:1, in particular in the range of 1.7:1 to 1.3:1, so that the shaping air is preferably discharged at a short distance from the axis of rotation (6) of the turbine shaft (5) to achieve a shaping air utilization optimized in terms of consumption.

7. A drive turbine (2) according to any one of the preceding claims, characterised in that The driving turbine (2) comprises: a) a radial bearing (10) for mounting the turbine shaft (5) in a bearing section (11) in the proximal shaft section (12), in particular as an air bearing, b) a ratio between the outer diameter (D1) of the turbine shaft (5) in the bearing section (11) and the inner diameter (D2) of the turbine shaft (5) in the bearing section (11) of at most 1.3:1, 1.2:1 or 1.15:1, in order to preferably achieve a low moment of inertia of the turbine shaft (5).

8. A drive turbine (2) according to any one of the preceding claims, characterised in that a) the turbine shaft (5) is hollow and contains a coating tube (7) having a coating tube outer diameter (D5) inside, and b) The ratio between the inner diameter (D2) of the turbine shaft (5) in the proximal shaft section (12) and the outer diameter (D5) of the paint tube is in the range of 1.005:1 to 1.5:1, in particular in the range of 1.01:1 to 1.3:1, so as to preferably generate a suitable pressure gradient.

9. A drive turbine (2) according to any one of the preceding claims, characterised in that a) the drive turbine (2) comprises an axial bearing with a rotating bearing disk for mounting the turbine shaft (5), the axial bearing being in particular an air bearing, b) the drive turbine (2) comprises a speed sensor having a rotating sensor disk for speed detection, c) the driving turbine (2) comprises a wheel (13) having a plurality of turbine blades (14), and d) The bearing disk, the sensor disk and the wheel (13) are integrated into one component.

10. A drive turbine (2) according to any one of the preceding claims, characterised in that a) an axial bearing for mounting the turbine shaft (5), the axial bearing being designed as an air bearing and discharging axial bearing exhaust gas during operation, b) a radial bearing (10) for mounting the turbine shaft (5), the radial bearing being designed as an air bearing and discharging radial bearing exhaust gas during operation, c) the drive turbine (2) is driven by drive air during operation and discharges turbine exhaust gas, d) the radial bearing exhaust gas in the driving turbine (2) is at least partially combined with the turbine exhaust gas, in particular the proportion of the radial bearing exhaust gas is in the range of 35%-75%, in order to increase the temperature of the turbine exhaust gas and thus avoid condensation, and / or e) The axial bearing exhaust in the driving turbine (2) is at least partially combined with the turbine exhaust, in particular the proportion of the axial bearing exhaust is in the range of 25%-65%, so as to increase the temperature of the turbine exhaust and thus avoid condensation.

11. A drive turbine (2) according to any one of the preceding claims, characterised in that a) the turbine rotor comprises at least one wheel (13) having a plurality of turbine blades (14), b) the drive turbine (2) has at least one drive air nozzle for blowing air toward the turbine blades (14) in a rotational drive direction for driving the turbine rotor, c) the drive turbine (2) has a plurality of brake air nozzles (26-28) for blowing air toward the turbine blades (14) in the direction opposite to the rotational drive direction to brake the turbine rotor, d) the brake air nozzles (26-28) are distributed around the circumference, e) the individual brake air nozzles (26-28) flow onto at least two or at least three turbine blades (14) at different flow angles, f) The turbine blades (14) are preferably all of the same design, without additional turbine blades of a different shape being used to brake the drive turbine (2).

12. A drive turbine (2) according to any one of the preceding claims, characterised in that a) the drive turbine (2) has a discharge device (29, 30, R) for discharging an electric potential from the turbine shaft (5), and / or b) the discharge device (29, 30, R) forms a discharge path (30) to the ground potential (GND), the resistance (R) of the discharge path (30) is less than 10 kΩ, and / or c) the discharge path (30) is in contact with the turbine shaft (5) at the distal shaft section (4) of the turbine shaft (5), in particular at an axial distance of less than 5 cm, 3 cm, 2 cm or 1 cm from the distal end of the turbine shaft (5), and / or d) the discharge device (29, 30, R) surrounds the turbine shaft (5) in an annular manner, i.e. surrounds the turbine shaft (5) in an annular manner in the axial direction between the radial bearing (10) and the distal end of the turbine shaft (5), and / or e) the discharge device (29, 30, R) forms a sealing structure that seals the radial bearing (10) relative to the environment, and / or f) The discharge device (29, 30, R) has a contact brush (29) or a foil or a discharge ring for making electrical contact with the turbine shaft (5).

13. A drive turbine (2) according to any one of the preceding claims, characterised in that a) the turbine shaft (5) is rotatably mounted in a radial bearing (10), b) the radial bearing (10) extends in the axial direction on a certain bearing section (11) located within the proximal shaft section (12), c) the radial bearing (10) has a specific bearing clearance in the radial direction, and d) The ratio between the axial length of the bearing segment (11) and the radial bearing clearance of the radial bearing (10) is in the range of 1000:1 to 8000:1, in particular in the range of 2000:1 to 6000:1, so as to preferably achieve sufficient stability and low bearing loss performance of the radial bearing (10).

14. A drive turbine (2) according to any one of the preceding claims, characterised in that a) the turbine shaft (5) is hollow, b) the hollow turbine shaft (5) comprises a plurality of main valves for controlling the distribution of the coating agent of the rotary atomizer, and there are no other valves downstream of the main valves, c) the number of main valves in the hollow turbine shaft (5) is greater than 2 or 3, in particular equal to 4, and / or d) Each main valve is designed as a needle valve with a displaceable valve needle which can open or close a valve seat depending on its position.

15. A drive turbine (2) according to any one of the preceding claims, characterised in that a) the turbine shaft (5) has only two different shaft diameters, namely a larger shaft diameter (D1) in the proximal shaft section (12) and a smaller shaft diameter (D4) in the distal shaft section (4), and / or b) the drive turbine (2) has a turbine housing (9), the turbine shaft (5) protrudes from the turbine housing (9) with the distal shaft section (4) in the axial distal direction, and / or c) the turbine shaft (5) has at its distal end a fastening device for fixing the bell cup (3), in particular a threaded portion for screwing the bell cup (3) onto the turbine shaft (5), in particular as an external threaded portion or an internal threaded portion, and / or d) the transition between different shaft diameters of the turbine shaft (5) occurs abruptly or continuously, and / or e) The driving turbine (2) is an axial flow turbine or a radial flow turbine.

16. A rotary atomiser (1) comprising a drive turbine (2) according to any one of the preceding claims.

17. A drive turbine (2) for a rotary atomizer (1), in particular a turbine shaft (5) for a drive turbine (2) according to any one of claims 1 to 15, characterized in that: The turbine shaft (5) is stepped along its axis of rotation (6) with different shaft diameters (D1, D2, D4), in particular with different inner diameters (D2) and / or different outer diameters (D1, D4).

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