WHEELSET WITH PRESSED CONNECTION FOR RAIL VEHICLES

Description

[0001] The invention relates to a wheelset for rail vehicles. The wheelset comprises at least one wheel and a wheelset axle with at least one interference fit. The wheel is joined to a wheel hub bore by longitudinal pressing or shrinking onto the interference fit of the wheelset axle.

[0002] Wheelsets, particularly in the form of running or driving wheelsets, are used in rail vehicles for freight wagons, passenger trains, locomotives, high-speed trains, local and regional trains, trams, light rail, suburban trains and underground trains.

[0003] In rail vehicle wheelsets, the shaft-hub connections between the wheelset shaft and the components to be pressed are primarily created by longitudinal pressing or shrinking. For this purpose, the components have a component hub bore, which is joined to a press fit on the wheelset shaft.

[0004] Wheelset components known from the prior art include, in particular, wheels and functional components, which include, for example, parts of a drive unit and / or parts of a braking system. In particular, brake discs, clutch parts, and transmission gears are functional components that are regularly pressed onto a press fit of the wheelset shaft.

[0005] The shaft-hub connections of the components on the wheelset axles are subject to stringent requirements for transmitting drive and braking torques, torques from torsional vibrations, torsional or rolling vibrations, bending moments, and axial forces. It must be ensured that the attachments do not slip axially or circumferentially during operation.

[0006] In particular, torsional vibrations can occur in rail vehicles when the traction is temporarily lost due to longitudinal slippage of the wheels on a rail. This leads to anti-phase vibrations of the two wheels against each other and thus to briefly very high torsional moments. In the past, these high torsional vibration moments have in some cases led to the wheels slipping circumferentially on the press fits of the wheelset shaft. It is safety-relevant that these briefly very high torsional moments are reliably transmitted without the wheels slipping in the press fit, thus preventing detrimental circumferential slipping of the wheels on the wheelset shaft seats.

[0007] It is known from the prior art to counteract the high torsional moments using slip control for drive systems, by reducing the occurrence of these very high torsional vibrations. Another known countermeasure against wheel slippage on the axle shaft seats due to high torsional moments is to install vibration dampers on the wheels.

[0008] It is known from the prior art that the component hubs must be pressed axially onto the press fit of the wheelset shaft using high forces and lubricants. Depending on the diameter of the press fit, press-on forces of, for example, 300 to 1500 kN are required. Molybdenum sulfide pastes, oils, or tallow are used as lubricants. The lubricant used reduces the coefficient of static friction in the press fit.

[0009] The requirements for joining wheelsets for railway applications are specified in particular in the standard "DIN EN 13260: 12-2020, Railway applications - Wheelsets and bogies - Wheelsets - Product requirements; German version EN 13260:2020".

[0010] The pressing of components, for example, during maintenance, is regularly performed using a pressure oil process. For this purpose, the components preferably have oil pressure holes and oil grooves in the respective hub bores. For pressing, the hub bores are pressurized with oil, expanding the components and allowing them to be pressed axially against the oil lubricating film.

[0011] However, pressing components onto or off the wheelset axle can result in damage caused by pressing in the form of longitudinal scoring and cold welding, which can render the components unusable. This is especially true if components are repeatedly pressed on and off during maintenance.

[0012] Furthermore, the dynamic stresses during operation can cause fretting corrosion at the edges of the press connections, which can lead to cracking.

[0013] DE 806 970 C discloses the application of a layer of a material with plain bearing properties between the axle hub seat and the wheel hub bore to prevent interference fit damage. Metallic materials such as tin or non-metallic materials such as plastics are said to be suitable for this purpose.

[0014] EP 1 379 709 B1 discloses a method for preventing interference fit damage on wheelset axles or for increasing the fatigue strength and reducing the formation of fretting corrosion in interference fits on wheelset axles. A sulfide-containing powder that reduces the coefficient of friction is applied to the surface of the interference fit of the wheelset axle using a plasma ion implantation process. This plasma treatment implants solid lubricant particles into the surface of the wheelset axle. This process is intended to increase hardness, which increases resistance to the occurrence of interference marks and thus ensures the fatigue strength of the interference fit of the wheelset axle.

[0015] CZ 26 638 U1 also deals with the prevention of interference fit damage and discloses the application of a surface coating to the wheel axle seating areas for various functional components such as wheels, gears, or bearings. Various metals and metal alloys, as well as oxide and non-oxide ceramics, are mentioned as examples.

[0016] US 2019 / 309382 A1 discloses an axle for a rail wheel, the surface of which is completely reinforced over its entire length by an induction hardened layer.

[0017] It is known from the prior art that a thermal coating of the press fits with almost pure molybdenum, which is often applied to the press fits of the wheelset shaft for the wheel hub bore, reduces press damage and fretting corrosion. In particular, the application of a chemically passive surface layer to the press fits of wheelset shafts is known from DE 10 2005 046 595 B4. This chemically passive surface layer hardens or strengthens the surface of the press fits of the wheelset shaft. DE 10 2005 046 595 B4 proposes mineral, ceramic, phosphate layers, or metal layers, such as molybdenum, as passive surface layers. The surface layer is preferably nitrided, which is intended to increase the fatigue strength of the wheelset shaft press fit. The disadvantage of these coatings, however, is that they are cost-intensive.

[0018] The surface treatments known from the prior art, in particular using a sulfide-containing powder that reduces the coefficient of friction, as described in EP 1 397 709 B1, or using a thermal molybdenum or a chemically passive surface layer, have proven advantageous for preventing interference fit damage to wheelset shafts due to pressing and / or pressing-off processes, or for increasing fatigue strength and reducing fretting corrosion. However, they could not increase the transmission capacity of axially acting forces or torsional and bending moments.

[0019] The invention is based on the object of providing a wheelset which overcomes the disadvantages known from the prior art, in particular avoiding slipping of the components, at least of the wheel, on the wheelset shaft, preferably while maintaining at least equivalent protection against press damage and fretting corrosion and at least the same fatigue strength of the wheelset shaft.

[0020] The object is achieved according to the invention by the features of claim 1. Due to the fact that a surface coating made of a non-ferrous metal or a non-ferrous metal alloy that increases adhesion relative to a material of the wheel is applied to the wheel hub bore of the wheel, and a surface coating (112) made of a non-ferrous metal or a non-ferrous metal alloy that increases adhesion relative to a material of the wheel (102) is applied to the wheel hub bore (110) of the wheel (102), and the surface coating consists of high-purity copper or a copper alloy made of high-purity copper, and the high-purity copper has purities of 90% to 99.9%, and the surface coating (112) in a raw, mechanically unfinished state has a roughness (Ra) of up to 30 µm, the static friction values ​​between the wheel and the wheelset shaft or between the wheel hub bore and the press fit of the wheelset shaft are greatly increased.The result is that the surface coating according to the invention introduces a suitable intermediate layer into the shaft-hub-seat pairings, which leads to a higher transferability of forces and torsional moments, particularly due to torsional vibrations, compared to conventional press connections and thus increases the resistance to slipping of at least the wheel on the wheelset shaft. Furthermore, the arrangement of this surface coating specifically on the wheel hub has the advantage over an arrangement on the press fit of the wheelset shaft that when the wheel is replaced, which occurs more frequently due to regular wear of the wheel, a new surface coating is automatically provided. Thus, the advantages of the adhesion-enhancing surface coating last for a long time without the need to replace the wheelset shaft, which involves extensive assembly work.

[0021] The invention provides an increase in the coefficient of static friction between the wheel hub bore and the press fit, resulting in a one-and-a-half to three-fold increase in the transmittable forces and torques from the drive and brake, as well as torsional vibrations, compared to prior art shaft-hub connections. This ensures safe operation and increases reliability.

[0022] Advantageously, the wheelset also provides a means of preventing press damage in the form of longitudinal scoring and cold welding during the pressing of the components onto and off the wheelset shaft by means of the surface coating according to the invention. Known lubricants can be conveniently dispensed with, at least during the pressing process, since the surface coating itself allows the components, in particular the wheel, to slide smoothly when being pressed onto the wheelset shaft and / or when being pressed off the wheelset shaft. This improves, in particular, the suitability for repeated pressing and off processes.

[0023] InIn an advantageous embodiment of the invention, the wheelset has at least one further press fit for additional functional components, in particular for parts of a drive unit and / or parts of a braking system. The functional components expediently each have a functional hub bore, with which they are joined at the press fit. Preferably, the functional components are pressed or shrunk onto the respective press fit of the wheelset shaft, analogous to the wheel.

[0024] In an advantageous variant, a surface coating made of a non-ferrous metal or a non-ferrous metal alloy that increases adhesion relative to a material of the wheelset shaft and / or the functional component is applied to the respective press fit of the wheelset shaft and / or to the functional hub bore of the respective functional component. This provides a higher transferability of forces and torsional moments, in particular due to torsional vibrations. With regard to the arrangement of the functional components on the wheelset shaft, the same advantages advantageously arise as are provided according to the invention with regard to the wheel on the wheelset shaft.

[0025] Examples of functional components are brake discs, especially shaft brake discs, clutch parts and transmission gears.

[0026] It has proven advantageous that the wheel and / or the functional components are made of steel and / or aluminum components and are pressed onto the respective press fit of the wheelset shaft.

[0027] It has proven particularly advantageous that the surface coating consists of high-purity copper with a purity of 99.9%.

[0028] In particular, the surface coating made of copper or a copper alloy has the advantage that no friction-reducing lubricant is required for pressing on the wheel and / or functional components from the wheelset axle, and the risk of damage such as scoring or cold welding is reduced when pressing the wheel and / or functional components off the wheelset axle. In addition to these advantages, the surface coating made of copper or a copper alloy effectively reduces fretting corrosion at the edges of the press fits of the wheelset axle. In particular, these advantages prevent any reduction in the fatigue strength of the wheelset axle due to damage during assembly and disassembly and / or fretting corrosion and / or bending moment and torsional stresses from operational use.In addition, the surface coating made of copper or a copper alloy has the particular advantage that the coefficient of static friction in an interference fit is very high, allowing higher axial forces, bending moments, and especially higher torsional moments to be transmitted than with conventional interference fits. Examples of prior art interference fits include the material pairings of steel and steel, or steel with a molybdenum coating and steel.

[0029] The surface coating can be applied, in particular as a sprayed layer, using conventional surface coating processes to the respective press fit of the wheelset shaft and / or in the respective wheel hub bore and / or the respective functional hub bore of the wheelset.

[0030] Thermal surface coating processes have proven to be advantageous, so the surface coating is preferably applied using a thermal surface coating process, in particular a thermal spraying process. Thermal surface coating processes advantageously achieve low porosity in the layer while simultaneously minimizing oxidation of the coating material.

[0031] In particular, this results in a high density and adhesion strength of the surface coating.

[0032] Exemplary surface coating processes used to apply the surface coating include, but are not limited to, flame spraying, in particular arc flame spraying, high-velocity flame spraying, plasma flame spraying, etc., and cold gas spraying. This allows the surface coating to be firmly applied to the respective press fit of the wheelset shaft and / or in the respective wheel hub bore and / or the respective functional hub bore of the wheelset, achieving low porosity, low oxidation of the coating material, high density, and high adhesion strength.

[0033] Alternatively, the surface coating can be applied by electroplating or a friction coating process.

[0034] The surface coating advantageously has a thickness in the range from 0.04 mm to 0.45 mm, in particular from 0.05 mm to 0.4 mm, particularly preferably from 0.08 mm to 0.255 mm. Surface coatings having a thickness in these ranges are particularly well suited, in terms of their adhesion and wear properties, for use on the respective press fit of the wheelset shaft and / or on the respective wheel hub bore and / or on the respective functional hub bore of the wheelset. The thickness of the surface coating is expediently selected according to the selected oversize for the components to be pressed onto the wheelset shaft, in particular the wheel and / or the functional components.

[0035] In a raw state, the surface coating of at least the wheel hub bore of one wheel, preferably also the functional hub bore of at least one functional component, expediently has a roughness (Ra) of up to 20 µm, preferably up to 15 µm. The as-sprayed state is, in particular, a state in which the surface coating has not been post-treated or reworked, in particular not mechanically reworked.

[0036] One variant of the wheelset provides for the wheelset axle and the respective wheel and / or the respective functional component to be joined together with the surface coating in its raw state. Depending on the application, mechanical post-treatment of the surface coating may be advantageous.

[0037] In particular, it is advantageous for the wheelset shaft to have an additional anti-corrosion coating and / or a shock-absorbing coating. Conventional coatings can be used for this purpose. It is expedient for the anti-corrosion coating and / or the shock-absorbing coating to be formed on at least one surface section of the wheelset shaft that is free from the surface coating. In particular, the areas of the wheelset shaft axially adjacent to the press fits are preferably coated with the additional anti-corrosion coating and / or the shock-absorbing coating.It is also additionally or alternatively advantageous that the wheelset shaft is provided with the corrosion protection seal and / or the shock-absorbing coating in the region of at least one gap of a hub edge, in particular a hub edge of the wheel hub bore and / or the functional hub bore, of at least one wheel and / or at least one functional component to the respective press fit.

[0038] The wheelset shaft is preferably joined to the wheel and / or the functional components using a longitudinal pressing process. The components are preferably pressed together using the well-known longitudinal pressing process without additional lubricants.

[0039] In particular, it is intended that the pressing process along the pressing diagram meets the product requirements for wheelsets of "DIN EN 13260: 12-2020, Railway applications - Wheelsets and bogies - Wheelsets - Product requirements; German version EN 13260:2020." Therefore, a joining speed should preferably be adapted to these requirements of "DIN EN 13260: 12-2020, Railway applications - Wheelsets and bogies - Wheelsets - Product requirements; German version EN 13260:2020."

[0040] It is particularly advantageous that at least one press fit of the wheelset shaft with the wheel hub bore of at least one wheel and / or the functional hub bore of at least one functional component is joined using the longitudinal pressing process at a joining speed in the range from 20 mm / min to 130 mm / min, in particular in the range from 30 mm / min to 120 mm / min, preferably in the range from 40 mm / min to 110 mm / min, advantageously in the range from 50 mm / min to 100 mm / min, particularly preferably 50 mm / min.

[0041] Expediently, the pressing of at least one wheel and / or at least one functional component from the wheelset shaft can be carried out by means of methods known from the prior art, in particular by means of the pressure oil method.

[0042] It is within the scope of the invention that all features relating to the surface coating relate to the surface coating on the respective press fit of the wheelset shaft and / or in the respective wheel hub bore and / or the respective functional hub bore of the wheelset.

[0043] Further advantageous embodiments of the invention emerge from the following description of the figures and the dependent subclaims.

[0044] They show: Fig. 1 shows an embodiment of a wheelset according to the invention with a wheelset shaft and two wheels joined on the wheelset shaft, Fig. 2 shows a sectional view of a press fit of the wheelset shaft of the wheelset according to Fig. 1axially to the wheelset shaft with a wheel joined on the press fit, Fig. 3 a sectional view of another wheelset shaft with two tire wheels and two functional components axially to the wheelset shaft and Fig. 4 a sectional view of another wheelset shaft with two solid wheels and two functional components axially to the wheelset shaft.

[0045] In the various figures of the drawing, identical parts are always provided with the same reference symbols.

[0046] With regard to the following description, it is claimed that the invention is not limited to the exemplary embodiments and not to all or several features of described combinations of features, but rather each individual partial feature of the / each exemplary embodiment is also important for the subject matter of the invention, both independently of all other partial features described in connection therewith and also in combination with any features of another exemplary embodiment.

[0047] In the Fig. 1 , 3 and 4 Each wheel set 100 is shown. The wheel set 100 shown is exemplary for rail vehicles. The wheel set 100 has at least one wheel 102, in the illustrated embodiment advantageously two wheels 102, and a wheel set shaft 104. Advantageously, the wheel set shaft 104, as shown in the Fig. 2 and 3 shown, has a hollow bore 106.

[0048] The at least one wheel 102 is in particular a solid wheel, shown in Fig. 4 , or as a rubber-sprung wheel or as a tyred wheel, shown in Fig. 3 The wheelset shaft 104 is formed in particular from a metallic material, in particular a ferrous metal or a ferrous metal alloy.

[0049] As particularly in the Fig. 2 , 3 and 4 As shown, the wheelset shaft 104 has at least one press fit 108. In particular, the Fig. 3 The illustrated wheelset shaft 104 advantageously has four press fits 108. The wheel 102 has a wheel hub bore 110, wherein the wheel 102 is joined to the wheel hub bore 110 by longitudinal pressing or shrinking on the press fit 108 of the wheelset shaft 104.

[0050] According to the invention, a surface coating 112 made of a non-ferrous metal or a non-ferrous metal alloy that increases adhesion relative to a material of the wheel 102 is applied to the wheel hub bore 110 of the wheel 102. The surface coating 112 is Fig. 2 shown.

[0051] The surface coating 112 has the advantageous property that, due to the adhesion, the static friction coefficients between the wheel 102 and the wheelset shaft 104, or between the wheel hub bore 110 and the press fit 108 of the wheelset shaft 104, are greatly increased. In particular, the surface coating 112 according to the invention leads to a higher transferability of forces and torsional moments, particularly due to torsional vibrations, compared to conventional press connections.

[0052] Torsional vibrations are also referred to as torsional or rolling vibrations, which can occur when, for example, the traction is temporarily lost due to longitudinal slip of the wheels 102 on the rail. This leads, as shown in the Fig. 1 and 4 illustrated by the arrows 114, leads to antiphase vibrations of the two wheels 102 against each other and thus to briefly very high torsional moments, which are reliably transmitted to the wheelset shaft 104 by means of the surface coating 112 according to the invention. According to the invention, the improved transferability of forces and torsional moments prevents the respective wheel 102 from slipping on its press fit 108 in the circumferential direction.

[0053] A further developed, in the Figs. 3 and 4In the embodiment shown, the wheelset 100 has at least one further press fit 108 for at least one further functional component 116. Functional components 116 can, in particular, be parts of a drive unit and / or parts of a braking system. The functional component 116 preferably has a functional hub bore 118, with which it is joined to the press fit 108 assigned to it. Depending on the joining method of the wheels 102 on the wheelset shaft 104, the functional component 116 is preferably pressed or shrunk onto the respective press fit 108.

[0054] In a further developed embodiment, a surface coating 112 made of a non-ferrous metal or a non-ferrous metal alloy that increases adhesion relative to a material of the wheelset shaft 104 and / or the functional component 116 is applied to the press fit 108 of the wheelset shaft 104 assigned to the functional component 116 and / or to the functional hub bore 118 of the respective functional component 116. In particular, this results in the same advantageous properties as in the wheel hub bore-press fit connection according to the invention by means of the surface coating 112.

[0055] The advantageous arrangement and press connection between the functional components 116 and the wheelset shaft 104 corresponds to the arrangement and press connection according to the invention between the wheel 102 and the wheelset shaft 104, as shown in Fig. 2 is shown.

[0056] Functional components 116 within the meaning of the invention are, in particular and not exclusively, brake discs, e.g., shaft brake discs, clutch parts and transmission gears. Fig. 3 a functional component 116 as a shaft brake disc 120 and a functional component 116 as a drive coupling 122 and in Fig. 4 a functional component 116 is designed as a gear 124.

[0057] At least one wheel 102 and / or at least one functional component 116 is expediently formed, in particular, from a metallic material, in particular a ferrous metal or a ferrous metal alloy. Preferably, at least one wheel 102 and / or at least one functional component 116 is formed from steel or aluminum.

[0058] The surface coating 112 consists of high-purity copper or a copper alloy of high-purity copper, wherein the high-purity copper has purities of 90% to 99.9%, preferably 99.9%.

[0059] A spraying process, particularly preferably a thermal spraying process, has proven to be an advantageous surface coating process, in particular a thermal surface coating process, for applying the surface coating 112, so that the surface coating 112 is preferably formed as a sprayed layer. Thermal surface coating processes advantageously achieve low porosity in the layer while simultaneously minimizing oxidation of the coating material. In particular, this results in a high density and adhesive strength of the surface coating 112.

[0060] The surface coating 112, in particular the surface coating 112 formed as a sprayed layer, is expediently applied using conventional surface coating methods to the respective press fit 108 of the wheelset shaft 104 and / or in the respective wheel hub bore 110 and / or the respective functional hub bore 118 of the wheelset 100.

[0061] For example, the surface coating 112 is applied in particular by means of flame spraying, arc flame spraying, high-velocity flame spraying, plasma flame spraying, etc., and cold gas spraying to the respective press fit 108 of the wheelset shaft 104 and / or in the respective wheel hub bore 110 and / or the respective functional hub bore 118 of the wheelset 100. Through these methods, the surface coating 112 is firmly applied to the respective press fit 108 of the wheelset shaft 104 and / or in the respective wheel hub bore 110 and / or the respective functional hub bore 118 of the wheelset 100, thereby achieving low porosity, low oxidation of the coating material, high density, and high adhesive strength.

[0062] According to a preferred embodiment, the surface coating 112, in particular the surface coating made of copper or a copper alloy, as in Fig. 2characterized, a thickness 126 in the range from 0.04 mm to 0.45 mm, in particular from 0.05 mm to 0.4 mm, particularly preferably from 0.08 mm to 0.255 mm. Due to their adhesion and wear properties, these thicknesses have proven particularly suitable for use on the respective press fit 108 of the wheelset shaft 104 and / or on the respective wheel hub bore 110 and / or on the respective functional hub bore 118 of the wheelset 100. The thickness 126 of the surface coating 112 is advantageously selected according to the selected oversize for the components to be pressed onto the wheelset shaft 104, in particular the at least one wheel 102 and / or the at least one functional component 116.

[0063] According to the invention, the surface coating 112 in a raw, non-mechanically reworked state has a roughness (Ra) of up to 30 µm, in particular up to 20 µm, preferably up to 15 µm.

[0064] A variant of the wheelset 100 provides that the wheelset shaft 104 and the respective wheel 102 and / or the respective functional component 116 are each joined together in the raw state with the surface coating 112. Depending on the application, the surface coating 112 is optionally chemically and / or mechanically post-processed / treated.

[0065] As in Fig. 2 As shown, an advantageous embodiment of the invention provides that the wheelset shaft 104 has an additional corrosion protection coating 128 and / or a shock-absorbing coating 130.

[0066] The anti-corrosive coating 128 and / or the shock-absorbing coating 130 is expediently applied to at least one surface section of the wheelset shaft 104 which is free from the surface coating 112, as shown in Fig. 2In an improved variant, in particular the areas of the wheelset shaft 104 axially adjacent to the press fits 108 are coated with the additional corrosion protection coating 128 and / or the shock-absorbing coating 130. This embodiment is particularly suitable in Fig. 2 shown.

[0067] Another advantageous variant is that the wheelset shaft 104 is provided with the anti-corrosive coating 128 and / or the shock-absorbing coating 120 in the region of at least one gap of a hub edge, in particular a hub edge of the wheel hub bore 110 and / or the functional hub bore 118, of at least one wheel 102 and / or at least one functional component 116 to the respective press fit 108.

[0068] The longitudinal pressing method has proven particularly advantageous for assembling the wheelset 100, or for joining the wheel 102 and / or the functional component 116, to the wheelset shaft 104. The components, in particular the at least one wheel 102 and / or the at least one functional component 116, are preferably pressed onto the wheelset using the known longitudinal pressing method and preferably without the use of additional lubricants.

[0069] The pressing process preferably meets the product requirements for wheelsets of "DIN EN 13260: 12-2020, Railway applications - Wheelsets and bogies - Wheelsets - Product requirements; German version EN 13260:2020" in the course of the pressing diagram. Therefore, a joining speed must be adapted in accordance with these requirements of "DIN EN 13260: 12-2020, Railway applications - Wheelsets and bogies - Wheelsets - Product requirements; German version EN 13260:2020".

[0070] One form of the invention provides that at least one press fit 108 of the wheelset shaft 104 with the wheel hub bore 110 of at least one wheel 102 and / or the functional hub bore 118 of at least one functional component 116 is joined using the longitudinal pressing process at a joining speed in the range from 20 mm / min to 130 mm / min, in particular in the range from 30 mm / min to 120 mm / min, preferably in the range from 40 mm / min to 110 mm / min, advantageously in the range from 50 mm / min to 100 mm / min, particularly preferably 50 mm / min.

[0071] According to the invention, the surface coating 112, in particular made of copper or a copper alloy, can achieve significantly higher press-on forces depending on the selected interference fit between the press fit 108 and the wheel hub bore 110 or the functional hub bore 118 and due to the higher coefficient of friction provided by the surface coating 112, in particular made of copper or a copper alloy. This also significantly increases the transmittable forces and moments, in particular the torsional moments, during operation of the wheelset 100. In particular, with a surface coating 112 made of copper, the press-on forces are one and a half to three times higher than with the material pairings known from the prior art, steel and steel, or steel with a molybdenum coating and steel, with the same interference.

[0072] For conventional wheelsets known from the state of the art, especially for the known material pairs steel and steel or steel with a molybdenum coating and steel, the oversize, depending on the nominal diameter, is according to "DIN EN 13260: 12-2020, Railway applications - Wheelsets and bogies - Wheelsets - Product requirements; German version EN 13260:2020" in a range of: 0 , 0010 ∗ D mm bis 0 , 0015 ∗ D mm + 0 , 06 mm .

[0073] For conventional wheelsets known from the prior art, without a surface coating 112 according to the invention, with the material pairing steel and steel of the press connection of the wheel on the wheelset shaft and a nominal diameter "D" of 171 mm, the above formula according to "DIN EN 13260: 12-2020, Railway applications - Wheelsets and bogies - Wheelsets - Product requirements; German version EN 13260:2020" results in an oversize range of:

[0074] In an embodiment of the wheel set 100 according to the invention, the interference fit of the press connection with the material pairing surface coating 112, e.g. made of copper, and steel is preferably in a range of: 0 , 0010 ∗ D mm bis 0 , 0025 ∗ D mm + 0 , 06 mm .

[0075] In particular, the oversize of the embodiment according to the invention with the material pairing surface coating 112, e.g. made of copper, and steel according to this formula compared to the prior art with the nominal diameter "D" of the press connection of 171 mm is in a range of:

[0076] The at least one wheel 102 and / or the at least one functional component 116 is expediently joined to the respective press fit 108 of the wheelset shaft 104 using a longitudinal pressing process with a pressing force that depends on the nominal diameter "D" of the press fit or the hub bore.

[0077] For state-of-the-art wheelsets, it is known to select the press-on force based on "DIN EN 13260: 12-2020, Railway applications - Wheelsets and bogies - Wheelsets - Product requirements; German version EN 13260:2020." For known wheelsets, the interval within which the press-on force "Ff" must be located depends on the force "F" specified in DIN EN 13260: 12-2020, Chapter 4.2.1. The specified force "F" (measured in kilonewtons) corresponds to four times the nominal diameter "D" (measured in millimeters) (F [kN] = 4 * D [mm]). According to the above-mentioned standard, the press-on force "Ff" must be between 0.85 F and 1.45 F.

[0078] For example, for a state-of-the-art wheelset with a press fit made of steel and steel and a nominal diameter of 171 mm, the force "F" is calculated using the formula according to DIN EN 13260: 12-2020, Chapter 4.2.1: F = 4 ∗ 171 = 684 kN

[0079] Accordingly, the pressing force "Ff" lies in a range of: Ff = 0 , 85 ∗ 684 kN bis 1 , 45 ∗ 684 kN = 581 kN bis 992 kN

[0080] In comparison, according to the invention, depending on the oversize of the press connection with the material pairing surface coating 112, e.g. made of copper, and steel with a nominal diameter "D" of 171 mm, the press-on force "Ff" is in a range of 1200 kN to 2800 kN.

[0081] In particular, the press-on force "Ff" determined in tests for the wheel hub bore 110 with the surface coating 112, which is joined to the press fit 108 of the steel wheelset shaft 104, with a nominal diameter "D" of 171 mm, is greater than or equal to 1488 kN, preferably greater than or equal to 1984 kN, and particularly preferably greater than or equal to 2228 kN. This corresponds to a factor of 1.5 to 2.25 compared to the maximum press-on force of 992 kN of the conventional wheelset.

[0082] Since the pressing-on force "Ff" is proportional to the sliding friction coefficient, the static friction coefficient after pressing is at least as high as the sliding friction coefficient. Tests have shown that the pressing-on force is increased by the surface coating according to the invention compared to the prior art for the same nominal diameter. Advantageously, the surface coating 112 significantly increases the static friction coefficient and thus also the transmittable forces and moments, especially the torsional moments, compared to conventional wheel sets.

[0083] For pressing the wheel 102 and / or the functional component 116 from the wheelset shaft 104, the methods known from the prior art, in particular the pressure oil method, have proven successful.

[0084] It is within the scope of the invention that all features relating to the surface coating 112 relate to both the surface coating 112 on the respective press fit 108 of the wheelset shaft 104 and / or the surface coating 112 in the respective wheel hub bore 110 and / or the surface coating 112 of the respective functional hub bore 118 of the wheelset 100.

[0085] The invention is not limited to the illustrated and described embodiments, but also encompasses all equivalent embodiments within the meaning of the invention. It is expressly emphasized that the embodiments are not limited to all features in combination; rather, each individual partial feature can also have an inventive significance in itself, independently of all other partial features. Furthermore, the invention is not yet limited to the combination of features defined in claim 1, but can also be defined by any other combination of specific features of all the individual features disclosed as a whole. This means that, in principle, practically every individual feature of claim 1 can be omitted or replaced by at least one individual feature disclosed elsewhere in the application. List of reference symbols

[0086] 100Wheelset 102Wheel 104Wheelset shaft 106Hollow bore 108Press fit 110Wheel hub bore 112Surface coating 114Anti-phase vibrations 116Functional component 118Functional hub bore 120Shaft brake disc 122Drive coupling 124Gear 126Thickness 128Anti-corrosion coating 130Shock-absorbing coating DNominal diameter FfPress-on force FSpecified force according to "DIN EN 13260: 12-2020, Railway applications - Wheelsets and bogies - Wheelsets - Product requirements; German version EN 13260:2020"

Claims

1. A wheelset (100) for rail vehicles, comprising at least one wheel (102) and a wheelset shaft (104) with at least one press fit (108), wherein the wheel (102) is joined to a wheel hub bore (110) by longitudinal pressing or shrinking on the press fit (108) of the wheelset shaft (104), characterized in that a surface coating (112) of a non-ferrous metal or a non-ferrous metal alloy which increases adhesion relative to a material of the wheel (102) is applied to the wheel hub bore (110) of the wheel (102), and the surface coating (112) consists of high-purity copper or a copper alloy of high-purity copper, and the high-purity copper degrees of purity of 90% to 99.9%has , and the surface coating (112) has a roughness (Ra) of up to 30 µm in a raw, mechanically non-reworked state.

2. Wheelset (100) according to claim 1, characterized in that the wheelset (100) has at least one further press fit (108) for at least one further functional component (116), in particular for a part of a drive unit and / or a part of a brake equipment, the functional component (116) having in each case a functional hub bore (118), with which it is joined to the press fit (108), in particular is pressed on or shrunk on, and a surface coating is applied to the press fit (108) of the wheelset shaft (104) and / or to the functional hub bore (118) of the respective functional component (116), in particular pressed on or shrunk, and a surface coating (112) of a non-ferrous metal or a non-ferrous metal alloy which increases the adhesion relative to a material of the wheelset shaft (104) and / or of the functional component (116) is applied to the press fit (108) of the wheelset shaft (104) and / or to the functional hub bore (118) of the respective functional component (116).

3. Wheelset (100) according to claim 1 or 2 , characterized in that the surface coating (112) of high-purity copper with a degree of purity of 99.9 %.

4. Wheelset (100) according to any one of claims 1 to 3 , characterized in that the surface coating (112) is applied by means of a thermal surface coating process.

5. Wheelset (100) according to any one of claims 1 to 4, characterized in that the surface coating (112) is formed as a spray coating.

6. Wheelset (100) according to any one of claims 1 to 5, characterized in that the surface coating (112) has a thickness (126) in the range from 0.04 mm to 0.45 mm, in particular from 0.05 mm to 0.4 mm, particularly preferably from 0.08 mm to 0.255 mm.

7. Wheelset (100) according to any one of claims 1 to 6, characterized in that the surface coating (112) has a roughness (Ra) of up to 20 µm, preferably up to 15 µm, in a raw, mechanically unfinished state.

8. Wheelset (100) according to any one of claims 1 to 7, characterized in that the respective wheel (102) and / or the respective functional component (116) is in each case pressed with the surface coating (112) in the raw state onto the respective press fit (108) of the wheelset shaft (104).

9. Wheelset (100) according to any one of claims 1 to 8, characterized in that the wheelset shaft (104) has an anti-corrosion coating (128) and / or a shock-absorbing coating (130).

10. Wheelset (100) according to claim 9, characterized in that the anti-corrosion coating (128) and / or the shock-absorbing coating (130) is formed at least on a surface section of the wheelset shaft (104) that is free from the surface coating (112).

11. Wheelset (100) according to claim 9 or 10, characterized in that the wheelset shaft (104) is provided with the corrosion protection coating (128) and / or the shock-absorbing coating (130) in the area of at least one gap between a hub edge of at least one wheel (102) and / or at least one functional component (116) and the respective press fit (108).

12. Wheelset (100) according to any one of claims 1 to 11, characterized in that at least the one press fit (108) of the wheelset shaft (104) is joined to the wheel hub bore (110) of the wheel (102) and / or the functional hub bore (118) of the functional component (116) at a joining speed in the range from 20 mm / min to 130 mm / min, in particular in the range from 30 mm / min to 120 mm / min, preferably in the range from 40 mm / min to 110 mm / min, advantageously in the range from 50 mm / min to 100 mm / min, particularly preferably 50 mm / min, using the longitudinal pressing method.