Drive turbine for a rotary atomiser

Abstract

The invention relates to a drive turbine (2) for a rotary atomiser, said drive turbine comprising a turbine rotor having a rotatably mounted turbine shaft (5). According to the invention, the turbine shaft (5) is stepped along its axis of rotation (6) with different shaft diameters (D1, D2, D4), in particular with different internal diameters (D2) and / or different external diameters (D1, D4).

Description

[0001] DESCRIPTION

[0002] Drive turbine for a rotary atomizer

[0003] Technical field of the invention

[0004] The invention relates to a drive turbine for a rotary atomizer, in particular for painting motor vehicle body components in a paint shop. Furthermore, the invention relates to a rotary atomizer with such a drive turbine according to the invention.

[0005] Background of the invention

[0006] In modern painting systems for painting motor vehicle body components, rotary atomizers are typically used as application devices. These are driven by a drive turbine with compressed air. The drive turbine has a turbine shaft, with a bell cup mounted at the distal end of the turbine shaft, for example by a screw connection between the turbine shaft and the bell cup. During painting, the turbine shaft with the attached bell cup rotates at high speed, with the bell cup throwing the paint to be applied from an annular spray edge and atomizing it. The paint is usually supplied to the bell cup via a paint tube located within the hollow turbine shaft and containing one or two main needle valves to selectively activate or deactivate the paint application.

[0007] In these known rotary atomizers, there is a design conflict regarding the diameter of the turbine shaft.

[0008] On the one hand, the largest possible inner diameter of the hollow turbine shaft is desired so that there is enough space within the turbine shaft to accommodate a paint tube with several main needle valves.

[0009] On the other hand, a large turbine shaft diameter leads to a correspondingly large moment of inertia, which requires a correspondingly large drive power. Furthermore, a large turbine shaft diameter also leads to a correspondingly large centrifugal force load and a correspondingly large centrifugal force-induced speed increase of the turbine shaft, which is undesirable.

[0010] For the technical background of the invention, reference should also be made to WO 2015 / 029 763 A1, US 2005 / 0001 057 A1, EP 0645 191 B1, EP 1 245 290 B1 and DE 10 2010013551 A1.

[0011] Description of the invention

[0012] The invention is therefore based on the object of solving the constructive conflict of objectives described above.

[0013] This object is achieved by a drive turbine according to the invention according to the main claim.

[0014] The drive turbine according to the invention is designed to drive a rotary atomizer, as is known per se from the prior art. It should be noted that the drive turbine according to the invention has a turbine rotor with a rotatably mounted turbine shaft, as already briefly described above with regard to the prior art. The invention resolves the design conflict described above by staggering the turbine shaft along its rotational axis with different shaft diameters, in particular with different inner diameters and / or different outer diameters. In the drive turbine according to the invention, the diameter of the turbine shaft is therefore not constant along its rotational axis.This statement regarding the different diameters of the turbine shaft preferably refers to the areas of the turbine shaft axially in front of and axially behind the impeller of the turbine rotor, since the impeller naturally has a larger outer diameter than the rest of the turbine shaft. Therefore, the turbine shaft according to the invention preferably also has different diameters, apart from the impeller.

[0015] In a preferred embodiment of the invention, the turbine shaft has 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 to the outer diameter of the turbine shaft. The large shaft diameter in the proximal shaft section then preferably enables the accommodation of a paint tube with several (e.g. three or four) main needle valves, whereby within the scope of the invention it is of course also possible for only a single main needle valve to be arranged in the paint tube. The smaller shaft diameter in the distal shaft section, on the other hand, ensures that the moment of inertia and the requirements for drive power do not become too great. The drive turbine according to the invention thus resolves the conflict of objectives mentioned at the outset.

[0016] In a preferred embodiment of the invention, the turbine shaft has a specific outer diameter in the proximal shaft section, wherein the turbine shaft in the proximal shaft section preferably carries at least one impeller with a plurality of turbine blades and / or contains a paint tube with a specific paint tube outer diameter.

[0017] The turbine shaft for receiving the paint tube is preferably hollow and has a specific inner diameter in the proximal shaft section. The inner diameter of the turbine shaft in the proximal shaft section is preferably in the range of 25 mm to 35 mm, with a range of 28 mm to 32 mm having proven particularly advantageous. In the preferred embodiment of the invention, the inner diameter of the turbine shaft in the proximal shaft section is 30.5 mm, although a deviation of ±0.5 mm is possible.

[0018] Furthermore, it should be noted that in the preferred embodiment, the drive turbine has at least one annular shaping air nozzle ring with a plurality of shaping air nozzles, wherein the individual shaping air nozzles can emit shaping air jets to shape the paint spray jet applied from the bell cup. This technique of shaping the paint spray jet by blowing shaping air onto the spray jet from behind is known per se from the prior art and is part of general technical knowledge, so no separate description is required in this regard. However, it should be noted that the shaping air nozzle ring has a specific diameter.

[0019] Furthermore, it should also be noted that the turbine shaft has a specific outer diameter in the distal shaft section and preferably has a mounting interface for mounting a bell cup to the turbine shaft. For example, the bell cup can be mounted to the turbine shaft using a screw connection, but other mounting methods are also feasible within the scope of the invention.

[0020] In the preferred embodiment of the invention, the drive turbine is characterized by specific diameter ratios of the turbine shaft, which are described below. For example, the outer diameter of the turbine shaft in the proximal shaft section is preferably larger than the outer diameter of the turbine shaft in the distal shaft section. This advantageously enables the combination of maximum installation space in the proximal shaft section within the hollow turbine shaft, on the one hand, with a minimal mass moment of inertia of the turbine shaft, on the other.

[0021] In this case, there is preferably a certain ratio between the outer diameter of the turbine shaft in the proximal shaft section on the one hand and the outer diameter of the turbine shaft in the distal shaft section on the other hand, which can be, for example, in the range from 1.1:1 to 1.6:1, whereby a range from 1.3:1 to 1.4:1 has proven to be particularly advantageous for this ratio.

[0022] Furthermore, it should be noted that the inner diameter of the turbine shaft in the proximal section is preferably larger than the outer diameter of the turbine shaft in the distal section. This also allows for the combination of maximum installation space in the proximal section within the hollow turbine shaft on the one hand, with a minimal mass moment of inertia of the turbine shaft on the other.

[0023] In this case, there is preferably a specific ratio between the inner diameter of the turbine shaft in the proximal shaft section on the one hand and the outer diameter of the turbine shaft in the distal shaft section on the other hand, which ratio can be in the range of 1.05:1 to 1.4:1, whereby a ratio in the range of 1.1:1 to 1.2:1 has proven to be particularly advantageous.

[0024] Furthermore, it should 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.

[0025] In this case, there is preferably a specific ratio between the diameter of the shaping air nozzle ring, on the one hand, and the outer diameter of the turbine shaft in the distal shaft section, on the other hand, which can be in the range of 1.1:1 to 1.9:1. A ratio value in the range of 1.3:1 to 1.7:1 has proven particularly advantageous in order to deliver the shaping air at the shortest possible radial distance from the axis of rotation of the turbine shaft for optimal consumption. When the shaping air is delivered at a large radial distance from the axis of rotation of the turbine shaft, correspondingly more shaping air must be delivered, so the shaping air nozzles should be located as close to the axis of rotation as possible.

[0026] In the preferred embodiment of the invention, the drive turbine has a radial bearing located in the proximal shaft section of the shaft turbine and extending in the axial direction over a specific bearing section. The bearing section is therefore preferably located entirely within the proximal shaft section with the larger shaft diameter. For example, this radial bearing can be designed as an air bearing (aerostatic or aerodynamic bearing). In this case, there is preferably a specific ratio between the outer diameter of the turbine shaft in the bearing section, on the one hand, and the inner diameter of the turbine shaft in the bearing section, on the other, in order to achieve a low moment of inertia of the turbine shaft. In the preferred embodiment, this ratio is a maximum of 1.3:1, 1.2:1, or 1.15:1.

[0027] As already mentioned above, the turbine shaft is preferably hollow and can accommodate a paint tube having a specific outer diameter. In this case, there is preferably a specific ratio between the inner diameter of the turbine shaft in the proximal shaft section, on the one hand, and the paint tube outer diameter, on the other hand. This ratio is preferably in the range of 1.005:1 to 1.5:1, with a value in the range of 1.01:1 to 1.3:1 having proven advantageous for achieving a suitable pressure drop.

[0028] In addition, the drive turbine preferably also has an axial bearing with a rotating bearing disk for supporting the turbine shaft, whereby the axial bearing can also be designed, for example, as an air bearing (aerostatic or aerodynamic bearing). In addition, the drive turbine according to the invention preferably has a speed sensor with a rotating sensor disk for speed detection, as is known per se from WO 2022 / 157098 A1. Furthermore, the drive turbine has an impeller with several turbine blades to accelerate or decelerate the turbine rotor. Within the scope of the invention, it is possible for the bearing disk, the sensor disk, and the impeller to be integrated into a single component. This integration of several functions (bearing disk, sensor disk, and impeller) into a single component makes it possible to reduce the complexity of the drive turbine.

[0029] It was already mentioned above that the axial bearing and the radial bearing can be designed as air bearings, which emit axial bearing exhaust air and radial bearing exhaust air, respectively, during operation. It should also be mentioned that the drive turbine is driven by drive air during operation and emits turbine exhaust air.

[0030] In the drive turbine according to the invention, it is preferably provided that the radial bearing exhaust air in the drive turbine is at least partially combined with the turbine exhaust air in order to increase the temperature of the turbine exhaust air and thereby prevent condensation. For example, the radial bearing exhaust air can be combined with the turbine exhaust air at a proportion of 35%-75% of the radial bearing exhaust air.

[0031] Furthermore, it is preferably also provided that the axial bearing exhaust air in the drive turbine is at least partially combined with the turbine exhaust air in order to increase the temperature of the turbine exhaust air and thereby prevent condensation in the drive turbine. For example, the axial bearing exhaust air can be combined with the turbine exhaust air at a proportion of 25%-65% of the axial bearing exhaust air.

[0032] It was already briefly mentioned above that the turbine rotor has an impeller with a plurality of turbine blades, wherein the turbine blades are blown with drive air from at least one drive air nozzle during operation in order to drive the drive turbine. In addition, a plurality of brake air nozzles are preferably provided in order to blow the turbine blades against the drive direction of rotation in order to be able to brake the turbine rotor. The brake air nozzles are preferably arranged distributed over the circumference of the impeller. It should be mentioned here that the individual brake air nozzles can each flow onto at least two or at least three of the turbine blades with different angles of attack. The turbine blades are preferably all of the same design, i.e. there is no separate, differently shaped turbine blade for braking the drive turbine.

[0033] When painting motor vehicle body components, electrostatic paint charging is usually carried out in order to increase application efficiency and minimize disruptive overspray. Within the scope of such electrostatic paint charging, it can be provided within the scope of the invention that the drive turbine has a discharge device for dissipating electrical potential from the turbine shaft. The discharge device preferably forms a discharge path to ground, wherein the discharge path preferably has a resistance of less than 10 kΩ. 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. This electrical contacting of the turbine shaft at its distal end is advantageous because the discharge path only runs over a small part of the turbine rotor and is therefore relatively short.

[0034] In the preferred embodiment of the invention, the deflection device surrounds the turbine shaft in an annular manner, specifically in the axial direction between the radial bearing and the distal end of the turbine shaft. The deflection device can also form a seal that seals the radial bearing from the environment. For example, the deflection device can comprise a brush or a foil for electrically contacting the turbine shaft.

[0035] It was already mentioned above that the turbine shaft is preferably rotatably mounted in at least one radial bearing, wherein the radial bearing extends in the axial direction over a specific bearing section located within the proximal shaft section of the turbine shaft. The radial bearing has a specific bearing gap in the radial direction. It is advantageous if the ratio between the axial length of the bearing section, on the one hand, and the radial bearing gap of the radial bearing, on the other hand, lies in the range of 1000:1 to 8000:1, with a value in the range of 2000:1 to 6000:1 having proven particularly advantageous in order to achieve sufficient stability and low bearing power losses of the radial bearing.

[0036] Within the scope of the invention, several main valves can be accommodated in the hollow turbine shaft to control the coating agent delivery from the rotary atomizer. The term "main valve" used within the scope of the invention implies, in accordance with the meaning of this term in technical terminology, that there is no further valve downstream of the respective main valve. The main valve therefore serves to switch the paint application on and off. The stepped shape of the turbine shaft makes it possible to arrange more than two, three, or even more than four main valves within the hollow turbine shaft. For example, a total of four main valves can be arranged in the hollow turbine shaft.It should be noted that the individual main valves are preferably designed as needle valves, each having a movable valve needle that, depending on its position, either opens or closes a valve seat, thereby activating or deactivating the paint delivery. In the preferred embodiment of the invention, the turbine shaft has only two different shaft diameters: the larger shaft diameter in the proximal shaft section and the smaller shaft diameter in the distal shaft section.

[0037] Furthermore, it should be mentioned that in the 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.

[0038] For example, the bell cup can be mounted to the distal end of the turbine shaft using a screw connection, as is known from the prior art. However, other fastening methods are also possible within the scope of the invention.

[0039] It was explained above that the turbine shaft has different diameters. It should be noted that the transition between the different diameters of the turbine shaft is preferably abrupt. However, it is also possible for the transition between the different diameters of the turbine shaft to be continuous, i.e., not abrupt.

[0040] Furthermore, it should be noted that the drive turbine can be either an axial turbine or a radial turbine. However, within the scope of the invention, a combination of an axial turbine and a radial turbine is also possible.

[0041] Furthermore, it should be noted that the invention not only claims protection for the drive turbine according to the invention described above. Rather, the invention also claims protection for a complete rotary atomizer with such a drive turbine. Finally, the invention also claims protection for a turbine shaft for a drive turbine of a rotary atomizer, wherein the turbine shaft is stepped along its rotational axis with different shaft diameters, as already described above. The turbine shaft according to the invention can therefore also have the features described above for the complete drive turbine as a replacement part or as an individual component.

[0042] Advantages of the invention

[0043] The invention offers the following advantages in particular: • A space for four main needle valves is provided in the turbine shaft.

[0044] • The drive turbine according to the invention has a small size.

[0045] • Weight savings through integration of several functions (bearing disc, sensor disc and turbine impeller) in one component.

[0046] • Optimized bearing clearance management.

[0047] • Improved braking performance.

[0048] • Better high voltage dissipation.

[0049] • Improved stability and robustness against imbalance.

[0050] Other advantageous developments of the invention are characterized in the subclaims or are explained in more detail below together with the description of the preferred embodiment of the invention with reference to the figures.

[0051] Brief description of the drawings

[0052] Figure 1 shows an external view of a rotary atomizer according to the invention.

[0053] Figure 2 shows a sectional view of the drive turbine of the rotary atomizer from Figure 1.

[0054] Figure 3 shows another sectional view of the drive turbine from Figure 2.

[0055] Figure 4A shows a perspective view of the impeller of the drive turbine with multiple turbine blades.

[0056] Figure 4B shows another perspective view of the impeller from Figure 4A.

[0057] Figure 4C shows a side view of the impeller from Figures 4A and 4B.

[0058] Figure 5 shows an enlargement of Figure 2 to illustrate the flow paths of the turbine exhaust air.

[0059] Figure 6 shows a sectional view of the drive turbine with several schematically illustrated brake air nozzles. Figure 7 shows a sectional view with a discharge device for electrostatic potential dissipation.

[0060] Detailed description of the drawings

[0061] The following describes the exemplary embodiment of a rotary atomizer 1 according to the invention, which can be used for painting motor vehicle body components in a painting system, as shown in the drawings. It should be noted that the rotary atomizer 1 is typically guided by a multi-axis painting robot, which, however, is not shown for the sake of simplicity.

[0062] The rotary atomizer 1 has a drive turbine 2 which rotates a bell cup 3 at high speed during painting operation, as is known per se from the prior art.

[0063] The bell cup 3 is mounted by means of a screw connection to a distal shaft section 4 of a rotatably mounted turbine shaft 5, as is also known from the prior art. However, it should be noted that the bell cup 3 does not necessarily have to be mounted to the turbine shaft 5 by means of a screw connection, since other fastening methods (e.g., clamping connections) are also possible within the scope of the invention. The turbine shaft 5, with the bell cup 3 mounted thereon, then rotates about a rotational axis 6 during painting.

[0064] The turbine shaft 5 is hollow and offers space in its interior for a paint tube 7, shown only schematically here, which can contain several main needle valves, as will be described in detail.

[0065] The drive turbine 2 further comprises a rear housing section 8 and a front housing section 9, as is known per se from the prior art.

[0066] In the front housing section 9 there is a radial bearing 10, which is designed as an air bearing and extends in the axial direction over a bearing section 11.

[0067] Furthermore, it should be mentioned that the turbine shaft 5 carries an impeller 13 with numerous turbine blades 14 in a proximal bearing section 12, as can be seen in particular from Figures 4A-4C, wherein the turbine blades 14 are shown only schematically here. The impeller 13 is surrounded on its circumference by a nozzle ring 15, which has a plurality of drive air nozzles distributed over the circumference for blowing air onto the turbine blades 14 of the impeller 13, as is known per se from EP 1 388 372 B1, so that the content of this earlier patent is fully applicable to the present description with regard to the structural design of the drive turbine 2.

[0068] The impeller 13 and the nozzle ring 15 are adjacent to another stationary ring 16, which contains an exhaust air duct 17 for receiving the turbine exhaust air. The exhaust air duct 17 in the stationary ring 16 then finally flows into a common exhaust air duct 18, which also receives radial bearing exhaust air from the radial bearing 10, as can be seen in Figure 3. This merging of the radial bearing exhaust air with the turbine exhaust air increases the exhaust air temperature at the turbine outlet and thus prevents condensation within the drive turbine 2.

[0069] Furthermore, it should be noted that the impeller 13 is also part of an axial bearing, which also discharges axial bearing exhaust air, which is also discharged into the common exhaust air duct 18, as can be seen in Figure 3. This also increases the exhaust air temperature at the turbine outlet, which prevents condensation within the drive turbine 2.

[0070] Furthermore, Figure 2 shows that the drive turbine 2 has a shaping air nozzle ring on its front end with numerous shaping air nozzles 19, which are arranged distributed over the circumference and each emit a shaping air jet 20. By emitting the shaping air jets 20, it is possible to shape the spray jet of paint emitted by the bell cup 3, as is known per se from the prior art.

[0071] The shaping air is supplied via a shaping air duct 21, wherein the shaping air duct 21 is fed with shaping air from an air chamber 22. The air chamber 22 is located between the front housing section 9 of the drive turbine 2 and an annular, circumferential housing cover 23. The supply of shaping air from the air chamber 22 is also described in a similar form in EP 1 384 514 B1, so that the content of this earlier patent is fully incorporated into the present description.

[0072] Furthermore, it should be mentioned that the impeller 13 of the drive turbine 2 contains an annular magnetic encoder 24 which enables magnetic speed measurement, as is known per se from WO 2022 / 157098 A1, so that the content of this patent publication with regard to speed measurement is to be fully attributed to the present description.

[0073] It should be noted that the impeller 13 fulfills three technical functions. Firstly, the impeller 13 enables a mechanical drive of the turbine shaft 5 by blowing air onto the turbine blades 14. Secondly, the impeller 13 also enables speed measurement using the annular magnetic encoder 24. Finally, the impeller 13 also forms part of the axial bearing of the drive turbine 2. This integration of three technical functions in the impeller 13 is advantageous because it allows for a reduction in the number of required components.

[0074] In this exemplary embodiment, the turbine shaft 5 does not have a uniform shaft diameter along the rotational axis 6. Rather, the outer diameter D1 of the turbine shaft 5 in the proximal shaft section 12 is larger 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 for combining the largest possible installation space within the turbine shaft 5 on the one hand with the lowest possible mass moment of inertia of the turbine shaft 5 on the other. The installation space within the hollow turbine shaft 5 is so large that the paint tube 7 can be designed accordingly large so that it can accommodate a total of four main needle valves.

[0075] Furthermore, it should be mentioned that the inner diameter D2 of the turbine shaft 5 in the proximal shaft section 12 is also larger than the outer diameter D4 of the turbine shaft 5 in the distal shaft section 4. Thus, the ratio D2:D4 is preferably in the range of 1.1:1 to 1.2:1. This is advantageous for combining the largest possible installation space within the turbine shaft 5 on the one hand with the lowest possible mass moment of inertia of the turbine shaft 5 on the other hand, as already mentioned above.

[0076] The diameter D3 of the shaping air nozzle ring with the shaping air nozzles 19 is preferably larger 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 consumption-optimized shaping air delivery at a short distance from the rotational axis 6 of the turbine shaft 5. When the shaping air is delivered at a large radial distance from the rotational axis 6 of the turbine shaft 5, correspondingly more shaping air must be delivered, so that the shaping air nozzles 19 should be located as close to the rotational axis 6 as possible. It should also be mentioned that the paint tube 7 in the hollow turbine shaft 5 has a specific outer diameter D5 that 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 in order to generate a suitable pressure drop.

[0077] Figure 3 also shows that the radial bearing exhaust air is routed via an exhaust air duct 25 into the common exhaust air duct 18. The exhaust air duct 18 thus receives the radial bearing exhaust air, the axial bearing exhaust air, and the turbine exhaust air.

[0078] Furthermore, Figure 6 shows that several brake air nozzles 26, 27, 28 are provided, which are only shown schematically here and serve to decelerate the drive turbine 2 by blowing brake air onto the turbine blades 14 in the opposite direction to the drive direction. The brake air nozzles 26-28 each blow brake air onto several of the turbine blades 14 at different angles of attack, which has proven advantageous.

[0079] Finally, Figure 7 shows a discharge device for electrostatic potential discharge from the turbine shaft 5, which is advantageous in the case of electrostatic paint charging.

[0080] For this purpose, the discharge device comprises an annular discharge device 29, which may consist of a contact brush and rests on the outer surface of the turbine shaft 5 and also forms a seal. The discharge device 29 is connected to ground GND via a discharge path 30, wherein the discharge path 30 has a resistance R<10 kΩ.

[0081] The invention is not limited to the preferred embodiment described above. Rather, a multitude of variants and modifications are possible, which also utilize the inventive concept and therefore fall within the scope of protection. In particular, the invention also claims protection for the subject matter and features of the subclaims, independently of the respective claims referred to, and in particular even without the features of the main claim. The invention thus encompasses various aspects of the invention that enjoy independent protection. This applies in particular to the ideas concerning the discharge device, the dimensioning of the bearing gap, the brake air flow, and the merging of the bearing air discharge with the turbine exhaust air. List of reference symbols

[0082] 1 rotary atomizer

[0083] 2 Drive turbine of the rotary atomizer

[0084] 3 bell plates

[0085] 4 Distal shaft section of the turbine shaft

[0086] 5 Turbine shaft

[0087] 6 Rotation axis of the turbine shaft

[0088] 7 Paint tube in the turbine shaft

[0089] 8 Rear housing section of the drive turbine

[0090] 9 Front housing section of the drive turbine

[0091] 10 radial bearings for the turbine shaft

[0092] 11 Bearing section of the radial bearing

[0093] 12 Proximal shaft section of the turbine shaft

[0094] 13 Impeller of the turbine rotor

[0095] 14 turbine blades on the impeller of the turbine rotor

[0096] 15 Nozzle ring with drive air nozzles for blowing the turbine blades of the impeller

[0097] 16 Fixed Ring

[0098] 17 Exhaust air duct

[0099] 18 exhaust air duct

[0100] 19 shaping air nozzles

[0101] 20 shaping air jet

[0102] 21 shaping air duct

[0103] 22 Air space for shaping air duct

[0104] 23 Housing cover to cover the airspace

[0105] 24 Ring-shaped magnetic encoder on the turbine wheel impeller for speed measurement

[0106] 25 exhaust air duct

[0107] 26-28 Brake air nozzles for blowing the turbine blades of the impeller

[0108] 29 Discharge device

[0109] 30 Discharge path of the discharge device

[0110] GND Ground

[0111] Dl Outer diameter of the turbine shaft in the proximal shaft section

[0112] D2 Inner diameter of the turbine shaft in the proximal shaft section

[0113] D3 Diameter of the shaping air nozzle ring

[0114] D4 Outer diameter of the turbine shaft at the distal end of the turbine shaft D5 Outer diameter of the paint tube in the turbine shaft

[0115] R resistance of the discharge path to ground

Claims

CLAIMS 1. Drive turbine (2) for a rotary atomizer (1), with a) a turbine rotor with a rotatably mounted turbine shaft (5), characterized in that b) the turbine shaft (5) is stepped along its axis of rotation (6) with different shaft diameters (Dl, D2, D4), in particular with different inner diameters (D2) and / or different outer diameters (Dl, D4).

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

3. 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 impeller (13) with a plurality of turbine blades (14) and / or a2) contains a paint tube (7) with a specific paint tube outer diameter (D5), b) the turbine shaft (5) is hollow for receiving a paint tube (7) of the rotary atomizer and has a specific inner diameter (D2) in the proximal shaft section (12), wherein the inner diameter (D2) in the proximal shaft section (12) is preferably in the range from 25 mm to 35 mm, in particular in the range from 28 mm to 32 mm, in particular with an inner diameter of 30.5 mm ± 0.5 mm, c) that the drive turbine (2) has at least one annular shaping air nozzle ring with several shaping air nozzles (19),wherein the shaping air nozzle ring has a specific diameter (D3), and / or d) that the turbine shaft (5) in the distal shaft section (4) has a specific outer diameter (D4) and preferably has a mounting interface, in particular a screw thread, for mounting a bell cup (3) on the turbine shaft (5).

4. Drive turbine (2) according to claim 3, characterized in that a) the outer diameter (Dl) of the turbine shaft (5) in the proximal shaft section (12) is larger than the outer diameter (D4) of the turbine shaft (5) in the distal shaft section (4), in order to preferably combine maximum installation space in the proximal shaft section (12) with a minimum mass moment of inertia of the turbine shaft (5), and / or b) that there is a ratio between the outer diameter (Dl) of the turbine shaft (5) in the proximal shaft section (12) on the one hand and the outer diameter (D4) of the turbine shaft (5) in the distal shaft section (4) on the other hand, which ratio is in the range from 1.1:1 to 1.6:1, in particular in the range from 1.3:1 to 1.4:

1.

5. 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 larger than the outer diameter (D4) of the turbine shaft (5) in the distal shaft section (4), in order to preferably combine maximum installation space in the proximal shaft section (12) with a minimum mass moment of inertia of the turbine shaft (5), and / or b) that there is a ratio between the inner diameter (D2) of the turbine shaft (5) in the proximal shaft section (12) on the one hand and the outer diameter (D4) of the turbine shaft (5) in the distal shaft section (4) on the other hand, which ratio is in the range from 1.05:1 to 1.4:1, in particular in the range from 1.1:1 to 1.2:

1.

6. Drive turbine (2) according to one of claims 3 to 5, characterized in that a) that 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) that between the diameter (D3) of the shaping air nozzle ring on the one hand and the outer diameter (D4) of the turbine shaft (5) in the distal shaft section (4) on the other hand there is a ratio which is in the range from 1.1:1 to 1.9:1, in particular in the range from 1.7:1 to 1.3:1, in order to preferably deliver the shaping air for consumption-optimized shaping air use at a short distance from the axis of rotation (6) of the turbine shaft (5).

7. Drive turbine (2) according to one of the preceding claims, characterized by a) a radial bearing (10) for supporting the turbine shaft (5) in a bearing section (11) within the proximal shaft section (12), in particular as an air bearing, b) a ratio of a maximum of 1.3:1, 1.2:1 or 1.15:1 between the outer diameter (Dl) the turbine shaft (5) in the bearing section (11) on the one hand and the inner diameter (D2) of the turbine shaft (5) in the bearing section (11) on the other hand, in order to preferably achieve a low moment of inertia of the turbine shaft (5).

8. Drive turbine (2) according to one of the preceding claims, characterized in that a) the turbine shaft (5) is hollow and contains the paint tube (7) with the paint tube outer diameter (D5) on the inside, and b) that between the inner diameter of the turbine shaft (5) (D2) in the proximal shaft section (12) on the one hand and the paint tube outer diameter (D5) on the other hand there is a ratio which is in the range from 1.005:1 to 1.5:1, in particular in the range from 1.01:1 to 1.3:1, in order to preferably generate a suitable pressure drop.

9. Drive turbine (2) according to one of the preceding claims, characterized in that a) the drive turbine (2) has an axial bearing with a rotating bearing disk, in particular as an air bearing, for supporting the turbine shaft (5), b) the drive turbine (2) has a speed sensor with a rotating sensor disk for detecting the speed, c) the drive turbine (2) has an impeller (13) with a plurality of turbine blades (14), and d) the bearing disk, the sensor disk and the impeller (13) are integrated in one component.

10. Drive turbine (2) according to one of the preceding claims, characterized in that a) an axial bearing is provided for supporting the turbine shaft (5), which is designed as an air bearing and releases axial bearing exhaust air during operation, b) a radial bearing (10) is provided for supporting the turbine shaft (5), which is designed as an air bearing and releases radial bearing exhaust air during operation, c) the drive turbine (2) is driven by drive air during operation and releases turbine exhaust air, d) the radial bearing exhaust air in the drive turbine (2) is at least partially combined with the turbine exhaust air, in particular with a proportion in the range of 35%-75% of the radial bearing exhaust air, in order to increase the temperature of the turbine exhaust air and thereby avoid condensation, and / or e) the axial bearing exhaust air in the drive turbine (2) is at least partially combined with the turbine exhaust air, in particular with a proportion in the range of 25%-65% of the Thrust bearing exhaust air to increase the temperature of the turbine exhaust air and thereby avoid condensation.

11. Drive turbine (2) according to one of the preceding claims, characterized in that a) the turbine rotor has at least one impeller (13) with a plurality of turbine blades (14), b) the drive turbine (2) has at least one drive air nozzle for blowing air onto the turbine blades (14) in a drive direction of rotation for driving the turbine rotor, c) the drive turbine (2) has a plurality of brake air nozzles (26-28) for blowing air onto the turbine blades (14) opposite to the drive direction of rotation for braking the turbine rotor, d) the brake air nozzles (26-28) are arranged distributed over the circumference, e) the individual brake air nozzles (26-28) each flow onto at least two or at least three of the turbine blades (14) with different angles of attack, f) the turbine blades (14) are preferably all of the same design without an additional, differently shaped turbine blade for braking the Drive turbine (2).

12. Drive turbine (2) according to one of the preceding claims, characterized in that a) the drive turbine (2) has a discharge device (29, 30, R) for discharging electrical potential from the turbine shaft (5), and / or b) the discharge device (29, 30, R) forms a discharge path (30) to ground (GND), wherein the discharge path (30) has a resistance (R) of less than 10 kΩ, and / or c) the discharge path (30) contacts the turbine shaft (5) at its distal shaft section (4), 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, namely in the axial direction between the radial bearing (10) and the distal end of the turbine shaft (5), and / or e) that the diverting device (29, 30, R) forms a seal which seals the radial bearing (10) from the environment,and / or f) that the diverting device (29, 30, R) has a contact brush (29) or a foil or a diverting ring for electrically contacting the turbine shaft (5).

13. Drive turbine (2) according to one of the preceding claims, characterized in that a) the turbine shaft (5) is rotatably mounted in a radial bearing (10), b) that the radial bearing (10) extends in the axial direction over a specific bearing section (11) which lies within the proximal shaft section (12), c) that the radial bearing (10) has a specific bearing gap in the radial direction, and d) that the ratio between the axial length of the bearing section (11) on the one hand and the radial bearing gap of the radial bearing (10) on the other hand is in the range from 1000:1 to 8000:1, in particular in the range from 2000:1 to 6000:1, in order to preferably achieve sufficient stability and low bearing power loss of the radial bearing (10).

14. Drive turbine (2) according to one of the preceding claims, characterized in that a) the turbine shaft (5) is hollow, b) the hollow turbine shaft (5) contains a plurality of main valves in order to control the coating agent discharge of the rotary atomizer, wherein there is no further valve downstream of the main valves, c) the number of main valves in the hollow turbine shaft (5) is greater than two or three, in particular equal to four, and / or d) the main valves are each designed as a needle valve with a displaceable valve needle which, depending on its position, either opens or closes a valve seat.

15. Drive turbine (2) according to one of the preceding claims, characterized in that a) the turbine shaft (5) has only two different shaft diameters, namely the larger shaft diameter (D1) in the proximal shaft section (12) and the smaller shaft diameter (D4) in the distal shaft section (4), and / or b) the drive turbine (2) has a turbine housing (9) and the turbine shaft (5) with the distal shaft section (4) protrudes from the turbine housing (9) in the axial distal direction, and / or c) the turbine shaft (5) has at its distal end a fastening device for fastening a bell cup (3), in particular a screw thread for screwing the bell cup (3) onto the turbine shaft (5), in particular as an external thread or as an internal thread, and / or d) the transition between the different shaft diameters of the turbine shaft (5) occurs abruptly or continuously,and / or e) that the drive turbine (2) is an axial turbine or a radial turbine., 16. Rotary atomizer (1) with a drive turbine (2) according to one of the preceding claims.

17. Turbine shaft (5) for a drive turbine (2) of a rotary atomizer (1), in particular for a drive turbine (2) according to 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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