Solid wheel with high thermal performance for rail vehicles

Abstract

Solid wheel (V) with high thermal performance for rail vehicles, with: - a radially outer wheel rim (1), - a radially inner wheel hub (2) which runs around a central axis (MA) of the solid wheel (V), and - a wheel disc (3) that connects the wheel rim (1) to the wheel hub (2), - wherein the wheel flange (1) has a running surface (4), a wheel flange (5), an outer side surface in a first plane (X1) and an inner side surface in a second plane (X2), - wherein the first plane (X1) and the second plane (X2) are orthogonal to the central axis (MA), - wherein the wheel rim (1) has a reference plane (C) running orthogonally to the central axis (MA) with a running circle diameter (LD) in the area of ​​its running surface (4), - wherein the reference plane (C) is shifted parallel outwards relative to the second plane (X2) and the inner side surface of the edge ring (1) by an axial distance (LC), wherein the distance (LC) is preferably 50 mm to 80 mm, - wherein the wheel rim (1), the wheel disc (3) and the wheel hub (2) are formed in one piece as a solid wheel (V), and - wherein the wheel disc (3) has a median line (ML) whose course is defined by several construction points (K1, K2, K3, K4), characterized in that the following conditions apply to the median line (ML) and to the construction points (K1, K2, K3, K4): a) first construction point (K1): - The first construction point (K1) is the intersection of a third plane (X3) running orthogonally to the central axis (MA), which determines the axial position, and a first straight line (G1), which determines the radial position. - The third plane (X3) is shifted parallel inwards relative to the reference plane (C) by an axial distance (A) and passes through the area of ​​the wheel flange (5). - The first straight line (G1) passes through a foot point (Y1) at the radially inner and axially outer corner of the wheel rim (1) and is inclined at an angle (α) between 0° and 14° to a second straight line (G2) that runs parallel to the central axis (MA). - The median line (ML) of the wheel disc (3) runs parallel to the reference plane (C) in the area of ​​the first construction point (K1). b) second construction point (K2): - The second construction point (K2) is the vertex of the median line (ML), i.e. the point of the median line (ML) furthest axially outside. - The second construction point (K2) is the intersection of a fifth plane (X5) running orthogonally to the central axis (MA), which determines the axial position, and a diameter (DK2), which determines the radial position. - The fifth plane (X5) is shifted parallel outwards relative to the reference plane (C) by an axial distance (B). c) third construction point (K3): - The third construction point (K3) is the intersection of a fourth plane (X4) running orthogonally to the central axis (MA), which determines the axial position, and a diameter (D3), which determines the radial position. - The fourth level (X4) lies between the third level (X3) and the fifth level (X5) and is shifted parallel to these two levels. d) fourth construction point (K4): - The fourth construction point (K4) is an inflection point where the curvature direction of the median line (ML) changes, or a point on a straight line adjacent to both ends of which the curvature direction of the median line (ML) changes.

Description

[0001] The invention relates to a solid wheel with high thermal performance for rail vehicles, comprising: a radially outer wheel rim, a radially inner wheel hub extending around a central axis of the solid wheel, and a wheel disc connecting the wheel rim to the wheel hub, wherein the wheel rim has a running surface, a flange, an outer side surface in a first plane, and an inner side surface in a second plane, wherein the first plane and the second plane extend orthogonally to the central axis, wherein the wheel rim has, in the region of its running surface, a reference plane extending orthogonally to the central axis with a running circle diameter, wherein the reference plane is offset parallel outwards relative to the second plane and the inner side surface of the rim by an axial distance, wherein the distance is preferably 50 mm to 80 mm, wherein the wheel rim, the wheel disc, and the wheel hub are formed integrally as a solid wheel.and wherein the wheel disc has a median line whose course is defined by several construction points.

[0002] The solid wheel according to the invention (also: “monoblock wheel”) is a solid wheel for rail vehicles, which is particularly suitable for use on the European rail network in accordance with the Technical Specifications for Interoperability TSI WAG (freight wagons) and TSI LOC & PAS (locomotives and passenger cars) and whose product requirements are described in EN 13262 and the requirements for the approval of such wheels are described in EN 13979-1.

[0003] The main application area of ​​the invention relates to wheelsets of freight wagons where braking is predominantly achieved with brake shoes acting directly on the wheel treads. The resulting frictional energy causes the wheel tread to heat up considerably, consequently creating a strong thermal gradient between the wheel hub and the wheel rim.

[0004] Increasing axle loads, higher speeds, and the switch from cast iron to composite brake shoes for acoustic reasons are leading to ever-increasing thermal stresses on the wheels. For example, the composite brake shoes (K and LL) that have been legally mandated in Germany since the end of 2020 have the significant advantage over cast iron shoes that the wheel treads do not become roughened and remain smooth, thus drastically reducing the noise emission of a passing freight car.

[0005] However, a disadvantage is the lack of heat dissipation via the brake pads, which occurs with cast iron brake blocks; that is, the entire braking energy is now largely introduced into the wheel rim of the wheel and then primarily released to the surrounding air via the wheel rim and wheel disc.

[0006] The braking energies to be considered in the design of wheels, which specifically take into account the conditions on the European rail network, are defined, among other things, by EN 13979-1. For example, solid wheels for freight wagons with a tread diameter of 920 mm must be designed for continuous braking for 45 minutes. The total braking energy generated during this standard design is 135 MJ. This braking energy results in average wheel flange temperatures of approximately 550°C, while even at the end of these braking cycles, the wheel hubs have only heated up to approximately 50°C. Due to the temperature, the wheel flange would want to expand, but this expansion is prevented by the existing temperature gradient, as the less heated wheel hub hardly expands.

[0007] The consequence of this is high thermal stresses exceeding the yield strength of the wheel materials used, resulting in plastic deformation. These stresses then manifest as residual stresses of the first type when the wheels cool. For example, in a solid-wheel (monoblock) rail wheel, tensile stresses act on the wheel disc during continuous braking due to the expanding rim in the radial direction, while compressive stresses develop in the circumferential direction due to the restriction of expansion by the comparatively cold wheel disc. After braking, the mechanisms of the heating process reverse; that is, the wheel rim now attempts to contract more strongly, but is prevented from doing so by the previously plasticized and now effectively enlarged wheel disc.The result is the development of tensile residual stresses in the wheel rim in the circumferential direction, while the wheel disc is compressed by the contracting rim. Depending on the wheel disc's design, this compression process can lead to high local bending stresses and associated axial deformations on the wheel disc side. Such axial deformations of the wheel disc, which also occur in reverse during braking, lead to a change in the axial position of the wheel rim relative to the wheel hub. These changes are strictly limited by standards, as they lead to alterations in the wheel back gauge and track gauge of the wheelsets, and thus, if the limit dimensions are exceeded, the reliable tracking of the wheelset on the track is directly affected.

[0008] The challenges faced by designers of solid wheels with block brakes, as mentioned in the introduction, have led to a wide variety of wheel disc shapes, ranging from straight to disc-spring-like shapes to various corrugated shapes with and without camber (camber refers to the offset of the wheel disc between the entry point in the wheel rim and the wheel hub). In Europe, as early as 1968, with the introduction of the Y25 bogie by the International Union of Railways (UIC), a standard freight wagon wheelset was introduced by its Research and Testing Office (ORE). This wheelset featured a corrugated wheel disc without camber and was originally intended to be suitable for a 25-tonne axle load.Due to the camber-free wheel disc, the wheel remains largely stable in terms of track width during block braking. However, despite its corrugation, the wheel disc, which is positioned in the plane of the measuring circle, exhibits a comparatively high radial stiffness. This leads to high local stresses in the wheel disc with partial plastic deformation during block braking, as well as significant restriction of expansion in the wheel rim. The result is high tensile residual stresses in the wheel rim after cooling. These tensile residual stresses are highly undesirable, especially when tread defects such as thermal cracks occur, as they can lead to crack propagation and ultimately wheel failure.

[0009] Possible improvements to this wheel design led to various solutions, briefly outlined below.

[0010] Document DE 23 62 434 A1 describes a wheelset for railway vehicles, dating back to the 1970s, which features a nearly straight wheel disc. Due to the balanced stress distribution across the wheel disc caused by the absence of any undulation, the track gauge stability of the wheel described therein is significantly reduced compared to the UIC standard freight wagon wheel. Accordingly, local stresses and strains within the wheel disc are also considerably lower due to the lack of bending. However, above a certain temperature, the entire thickness of this wheel disc undergoes plastic deformation, which, in addition to affecting the load-bearing capacity in the wheel / rail forces, also results in increased tensile residual stresses in the wheel rim.

[0011] Document DE 31 17 572 C2 has described a solid wheel for rail vehicles with a bell-shaped profile since the 1980s. This wheel also features a camber-free disc with a corrugation that follows a mathematical function, and a thin, nearly constant disc thickness. Consequently, the radial stiffness of this wheel is significantly reduced compared to the aforementioned wheel designs. However, due to the verification requirements for mechanical stresses according to the subsequently developed standards, the originally planned thin discs are no longer feasible. This results in higher radial stiffness of the disc and less favorable stress and strain behavior during block braking.

[0012] Document EP 0 798 136 A1 has disclosed a wheel disc since the 1990s whose shape corresponds approximately to half the corrugation of the wheel according to DE 31 17 572 C2, with the corrugation depth being evenly distributed on both sides of the reference plane or measuring circle plane. This gives the wheel disc a camber corresponding to the depth of the corrugation, and the wheel disc is oriented towards the flange at the transition to the wheel rim and towards the outer hub face at the transition to the wheel hub. Due to the camber of the wheel disc, this design exhibits increased radial elasticity compared to the design according to DE 31 17 572 C2, resulting in further reduced residual stresses in the wheel rim, particularly compared to the UIC / ORE wheel. However, the shape of the wheel disc leads to increased axial deflections, especially after the wheels have cooled down, as well as increased cyclic stresses from the wheel / rail forces occurring during operation.

[0013] Document EP 1 225 065 A1 relates to a wheel disc with a corrugation similar to DE 31 17 572 A1, wherein the maximum of the corrugation has been shifted so far that it approximately coincides with the plane formed by the outer wheel rim face and the transition from the wheel rim to the wheel disc or from the wheel disc to the wheel hub has been shifted from the reference plane towards the outside of the wheel, i.e. further below the running surface.

[0014] Document EP 1 440 817 A1 describes two wheel modifications which are fundamentally based on the corrugation design according to DE 31 17 572 A1, except that the area of ​​maximum corrugation is not formed by a curvature but by a (in cross-section) straight or flat section. The wheel disc can be designed with or without camber, with the entry of the wheel disc into the wheel rim and hub oriented to the reference plane or measuring circle plane. The distinguishing feature between the two described wheel designs is that the entry of the wheel disc into the wheel rim and hub is at an angle, or alternatively, is perpendicular, i.e., parallel to the reference plane.

[0015] Document EP 2 046 585 B1 describes a freight wagon wheel whose corrugated wheel disc moves on both sides relative to the reference plane, with the crest of the corrugation oriented towards the outside of the wheel and the point where the wheel disc meets the hub and wheel rim oriented towards the inside of the wheel. The crest of the corrugation, located between the inner diameter of the wheel rim and the outer diameter of the hub, is offset towards the wheel rim, and the defined radii of the individual sections of the median line of the wheel disc determine its curvature.

[0016] In the solution known from document EP 2 801 483 A1, the shape of the wheel disc is based in principle on EP 0 798 136, whereby the radius of the wheel disc's centerline between the turning point and the transition to the wheel hub is smaller than the radius at the transition to the wheel rim. Furthermore, the distance between the corrugation at the transition to the wheel rim and the center plane of the corrugations is greater than the distance between the corrugation at the transition to the wheel hub.

[0017] Document EP 3 932 690 A1 also describes two wheel variants, which are essentially based on EP 0 798 136 and differ primarily in the design of how the wheel disc enters the wheel rim. In the first version, the wheel disc also follows a semi-circular profile, with the disc even projecting slightly beyond the inner rim face on the inside of the wheel. The wheel disc then enters the rim at an angle towards the wheel's reference plane, while the wheel disc enters the hub parallel to this plane. Alternatively, a reinforcement is provided below the rim on the running surface side, into which the wheel disc enters at the aforementioned angle.

[0018] In summary, it must be stated that the previously described designs already exhibit improvements in thermal behavior compared to the original so-called UIC / ORE wheel. However, depending on the specific design and the amount of braking energy applied, axial deflections exceeding the limits, as well as high thermal stresses and the resulting residual stresses, still occur. The present invention overcomes these issues, thus providing a wheel that is ideally suited for future increases in axle loads and speeds while retaining the block brake.

[0019] Against this background, the invention is based on the objective of further increasing the thermal performance of monoblock wheels beyond the level achieved so far, without impairing the mechanical properties of the wheel.

[0020] This task is solved for a solid wheel described at the beginning by ensuring that the following conditions apply to the median line and the construction points, and that these conditions must be cumulatively met: a) First construction point: - The first construction point is the intersection of a third plane running orthogonally to the central axis, which determines the axial position, and a first straight line, which determines the radial position. - The third plane is shifted parallel inwards by an axial distance relative to the reference plane and runs through the area of ​​the wheel flange. - The first straight line passes through a foot point at the radially inner and axially outer corner of the wheel rim and is inclined at an angle α, which is between 0° and 14°, to a second straight line that runs parallel to the central axis. - The median line of the wheel disc runs parallel to the reference plane in the area of ​​the first construction point. b) second construction point: - The second construction point is the vertex of the median line, i.e., the point of the median line furthest axially outward. - The second construction point is the intersection of a fifth plane running orthogonally to the central axis, which determines the axial position, and a diameter, which determines the radial position. - The fifth plane is shifted parallel outwards by an axial distance relative to the reference plane. c) Third construction point: - The third construction point is the intersection of a fourth plane running orthogonally to the central axis, which determines the axial position, and a diameter, which determines the radial position. - The fourth level lies between the third level and the fifth level and is shifted parallel to these two levels. d) fourth construction point: - The fourth construction point is an inflection point where the curvature direction of the median line changes, or a point on a straight line adjacent to both ends of which the curvature direction of the median line changes.

[0021] The invention relates to a solid wheel with high thermal performance for rail vehicles, comprising: a radially outer wheel rim, a radially inner wheel hub extending around a central axis of the solid wheel, and a wheel disc connecting the wheel rim to the wheel hub, wherein the wheel rim has a running surface, a flange, an outer side surface in a first plane, and an inner side surface in a second plane, wherein the first plane and the second plane extend orthogonally to the central axis, wherein the wheel rim has, in the region of its running surface, a reference plane (also called a measuring circle plane) extending orthogonally to the central axis with a running circle diameter, wherein the reference plane is shifted parallel outwards relative to the second plane and the inner side surface of the rim by an axial distance, wherein the distance is preferably 50 mm to 80 mm, wherein the wheel rim,the wheel disc and the wheel hub are formed in one piece as a solid wheel, and the wheel disc has a median line whose course is defined by several construction points.

[0022] According to the invention, it has been recognized that the problem set out in the invention can be solved advantageously in such a solid wheel if the conditions mentioned in the characterizing part of claim 1 are cumulatively fulfilled for the median line and for the construction points.

[0023] The advantages of the described solid wheel become apparent in the following evaluation during a block braking test with a continuous braking power of 50 kW for 45 minutes using composite brake shoes. While the rim of the UIC / ORE wheel with a 920 mm diameter can expand radially by 2.0 mm relative to the wheel diameter, the radial expansion of the new solid wheel is 3.1 mm. This expansion is already in the direction of a rim that is coupled to the wheel disc by a split connection, which does not impede the radial expansion of the rim under temperature influences. In this hypothetical solution, the rim would be able to expand radially by 3.9 mm.

[0024] This results in the residual tensile stresses in the wheel rim, even in a worn state, reaching maximum values ​​of approximately 50 N / mm² in relation to the UIC-ORE wheel. 2The stress is not exceeded while maintaining extremely stable track dimensions. At this stress, the associated stress intensity of a possible, reliably detectable crack in the area of ​​the wheel rim is significantly below the threshold value, thus preventing crack growth should such material damage occur.

[0025] As previously explained, the second construction point is the vertex of the median line, i.e., the point furthest axially outward on the median line. To define the axial position of this vertex more precisely, and in particular to prevent the wheel disc from protruding axially outward beyond the outer surface of the wheel rim, the following relationships were determined: The axial distance B of the vertex of the median line from the reference plane C should be as follows: B=(RB−LC)*0.3 to 0.9

[0026] In other words, the reference plane has an axial distance LC to the inner side surface of the wheel rim; the axial distance between the reference plane and the outer side surface of the wheel rim is therefore "RB - LC". However, the vertex of the median line should be shifted less far axially outwards, namely by only 30% to 90% of this distance (0.3 times (RB - LC) to 0.9 times (RB - LC)). This ensures that not only the vertex of the median line, but (at least with typical wheel disc thicknesses) no point of the wheel disc protrudes axially outwards beyond the outer side surface of the wheel rim. This has the advantage that the wheel disc does not protrude from the "shadow" of the wheel rim, thus preventing collisions with wheelset bearing housings, chassis frames, and the like.

[0027] According to one embodiment of the solid wheel, the running circle diameter is intended to be in the range of 600 mm to 1250 mm, and in particular between 840 mm and 920 mm. Running circle diameters in the range of 920 mm are especially preferred. Solid wheels with such running circle diameters are particularly suitable for freight transport, where the challenge of improving thermal performance is particularly significant due to the use of composite brake shoes.

[0028] Another embodiment of the solid wheel provides that the thickness of the wheel disc adjacent to the wheel hub is greater than the thickness of the wheel disc adjacent to the wheel rim (1), preferably with the following properties: 1.05 * S1 ≤ S2 ≤ 1.95 * S1. The wheel disc should therefore taper from the inner wheel hub towards the outer wheel rim. A wheel disc with variable thickness, unlike a wheel disc with constant thickness, has the advantage of being able to adapt the thickness to the locally prevailing mechanical requirements. The tapered shape is chosen because the mechanical stresses on the wheel primarily result from the lateral force acting on the wheel rim, and thus the bending stress acting in the wheel disc reaches its maximum at the transition from the wheel disc to the wheel hub.Furthermore, this can reduce the stiffness of the wheel disc towards the wheel rim, which benefits the thermal expansion capacity of the wheel rim and also reduces the wheel weight in the sense of lightweight construction.

[0029] The radially outer part of the wheel disc can be further designed by providing a first section between the first and fourth design points, which is curved and preferably has a constant curvature throughout. The first section can therefore be curved in sections or completely, and in particular circular. Alternatively or additionally, the wheel disc can be provided with a second section between the fourth and second design points, which is curved and preferably has a constant curvature throughout. The second section can also be curved in sections or completely, and in particular circular. In a curved design of the first and second sections, it can be provided that the first and second sections have opposite directions of curvature.The opposing curvatures can merge at a (turning) point; however, it can also be provided that a straight line running through the fourth design point is provided between the opposing curvatures, parallel to the central axis or at an angle to it. A straight line may be necessary for wheels with a particularly large tread diameter. Opposing curvature directions result in an S-shaped profile with a change from a "left curve" to a "right curve" (or vice versa). This design allows for particularly advantageous adjustment of the radial stiffness and the thermal expansion behavior of the wheel disc. Furthermore, this shape preferably results in bending stresses in the wheel disc, in contrast to the dominant normal stress components in straight wheel disc shapes.This prevents otherwise possible complete plasticization of entire wheel disc areas, and only partial plasticization occurs.

[0030] The radially inner part of the wheel disc can be further designed by having a third section adjacent to the second design point and a fourth section adjacent to the third design point, both exhibiting opposite directions of curvature. Here, too, the previously mentioned advantages and properties of opposite directions of curvature have been recognized and utilized. It is further proposed that the third section be curved and preferably have a constant curvature throughout. The third section can therefore be partially or completely circular. With regard to the fourth section, it is proposed that the fourth section be at least partially curved and / or at least partially straight.The fourth section therefore does not need to be completely curved and, in particular, does not need to have a constant curvature; it can even be straight in sections, especially in the area adjacent to the wheel hub, i.e., in the "entry" into the wheel hub. This allows the transition between the wheel disc and the wheel hub to be designed as desired. In the area of ​​the wheel hub, the highest possible radial stiffness is desirable to achieve a sufficiently strong bond between the wheel and the axle. In this respect, for example, wheel disc profiles with a steeper incline entering the wheel hub are counterproductive.

[0031] The invention is explained in more detail below with reference to a drawing, which merely represents a preferred embodiment. The drawing shows: Fig. 1: A solid wheel according to the invention in a cutaway view.

[0032] Fig. Figure 1 shows a solid wheel V according to the invention in a sectional view. The solid wheel V initially has a radially outer wheel rim 1. The radial direction is in Fig. The axial direction is indicated by the coordinate y (represented as an arrow), where the positive y-direction points radially outwards, while the negative y-direction points radially inwards (i.e., towards a wheel center axis MA). The coordinate x (also represented as an arrow) indicates the axial direction, where the positive x-direction points axially inwards (i.e., towards the center of the wheelset or towards the opposite solid wheel), while the negative x-direction points axially outwards.

[0033] The solid wheel V also has a radially inner wheel hub 2 and a wheel disc 3 that connects the wheel rim 1 to the wheel hub 2. The wheel rim 1 has a running surface 4 and a flange 5. The running surface 4 runs on the rail and can simultaneously serve as a braking surface for a friction brake. The flange 5, on the other hand, serves to transmit axial wheel guidance forces. The wheel rim 1, the wheel disc 3, and the wheel hub 2 are formed in one piece, which is why such wheels—in contrast to multi-part wheels—are also referred to as "solid wheels" or "monoblock wheels." The wheel disc 3 has a median line ML, the course of which is defined by several construction points K1, K2, K3, K4.

[0034] The wheel rim 1 has an axially outer side surface in a first plane X1 and an axially inner side surface in a second plane X2. Between the outer side surface (or the first plane X1) and the inner side surface (or the second plane X2) of the wheel rim 1 is a reference plane C of the solid wheel V, defined as the measuring circle plane. A running circle diameter LD is measured in the reference plane C. Furthermore, the reference plane C serves as the starting point for different wheel profiles, which apply depending on the applicable norm or standard. The transverse dimensions of the wheelset, which are crucial for safe track guidance in the rail network, are derived from these norms or standards. For example, a measurement circle diameter LD is created between the inner side surface (or the first plane X1) and the inner side surface (or the second plane X2).The distance LC between the second level X2) of the wheel flange 1 and the reference plane C is, for example, 70 mm (Technical Specification Interoperability for the railway system in the European Union for the subsystems rolling stock - freight wagons as well as locomotives and passenger cars - uniformly for track gauges 1435, 1524, 1600 and 1668 mm). For railways outside this group of operators, the standards applicable there must be applied. The wheel flange 1 has a radial thickness RD, which is composed of a wear component VA and the residual wheel flange thickness RRD, which must not be undercut during operation for reasons of strength (RD = VA + RDD). The wheel flange 1 also has an axial width RB, which is preferably in the range between 120 mm and 150 mm and can particularly be 135 mm.

[0035] The wheel hub 2 provides the secure connection of the solid wheel V with the (in Fig.1 (not shown) wheelset axle. It is typically cold-pressed or hot-shrunk onto an interference fit. The wheel hub 2 has a bore diameter D1N, which is determined by the fatigue strength verification for the interference fit, as specified in the applicable standards, in Europe according to EN 13103-1. The interference between wheel hub 2 and interference fit depends on the loads occurring on the wheelset, such as braking torques, short-circuit torques, the lateral forces between wheel and rail, the process parameters during assembly, and the temperature gradients within the wheel and between wheel and axle, and is preferably between 0.75‰ and 2.5‰.

[0036] The wheel hub 2 has an axial outer hub diameter D2a and an axial inner hub outer diameter D2i. The following applies to these: 1.14*D1N≤D2a or D2i≤1.55*D1N.

[0037] The entry of the median line ML of the wheel disc 3 into the wheel rim 1 runs parallel to the reference plane C in an imaginary third plane X3 at an axial distance A. This third plane X3 is to be determined such that the entire thickness S1 of the wheel disc 3 lies within the area of ​​the flange 5 at the point of entry into the wheel rim 1 (this should apply at least to a wheel with a flange in its new condition). The intersection of this third plane X3 with the inner diameter of the wheel rim D4 gives the first construction point K1 of the wheel disc 3. The inner diameter of the wheel rim D4 is determined by a base point Y1 of the wheel rim 1 and a first straight line G1, which runs at an angle α between 0° and 14° (inwards) to a second straight line G2 running axially (i.e., parallel to the wheel center axis MA).

[0038] The wheel disc 3, extending from the first construction point K1 towards the wheel hub 2, describes a "wave crest" with its median line ML, which points outwards in the axial direction. This wave crest begins – starting at the wheel rim 1 – with a curved (e.g., circular) rising first section A1 up to the fourth construction point K4 (which mathematically represents a "turning point" where the direction of curvature changes; alternatively, the fourth construction point can be part of a straight line whose two ends border opposite curvatures), followed by a curved (e.g., circular) flattening second section A2 with the second construction point K2 as the vertex of the wave crest. This is followed – further towards the wheel hub 2 – by a curved (e.g.,a circularly descending third section A3 and a fourth section A4 that is at least partially curved and flattening, with a tangential transition into a fourth plane X4 running parallel to the reference plane C, with the third construction point K3 as the endpoint of the wheel disc 3, through which the entry into the wheel hub 2 is defined.

[0039] The third construction point K3 is an intersection point with a hub diameter D3, which is formed according to the relationship: D3 = Maximum value(D2a,D2i) + Minimum value(L2a,L2i) * 0.15 to 0.6

[0040] L2a corresponds to the axial distance between an (axially outer) hub outer end face in a seventh plane X7 and the fourth plane X4, and L2i corresponds to the axial distance between an (axially inner) hub inner end face in a sixth plane X6 and the fourth plane X4. The distance of the fourth plane X4 is preferably located in the x-direction between the third plane X3 (first construction point K1) and the fifth plane X5 (second construction point K2).

[0041] The second construction point K2 of the wheel disc 3 is formed from the intersection point between the second construction point K2 of the median line ML and the fifth plane X5 running parallel to the reference plane C, where: DK2=0.35 to 0.6*(D4−D3)+D3

[0042] The axial distance B of this fifth plane X5 from the reference plane C is given as follows: B=(RB−LC)*0.3 to 0.9

[0043] The thickness of wheel disc 3 is determined based on numerical calculations and must take into account not only thermal stresses but also, in particular, cyclic stresses due to wheel / rail forces. This is addressed by ensuring that the profile of wheel disc 3 tapers towards wheel rim 1 along the median line ML between design points K3 and K4, with the following ratios for thickness S1 (adjacent to wheel rim 1) and thickness S2 (adjacent to wheel hub 2): 1.05*S1≤S2≤1.95*S1

[0044] The transition from the wheel disc 3 to the wheel hub 2 and from the wheel disc 3 to the wheel rim 1 is achieved by radii or elliptical transitions connecting the outer surfaces of the wheel hubs or inner surfaces of the wheel rims with the wheel disc in a tangential manner. Reference symbol list: 1 wheel rim 2 Wheel hub 3 Wheel disc 4 Running surface 5 wheel flange A axial distance (between reference plane C and third plane X3) A1 first section (of the median line ML / of the wheel disc 3) A2 second section (of the median line ML / of the wheel disc 3) A3 third section (of the median line ML / of the wheel disc 3) A4 fourth section (of the median line ML / of the wheel disc 3) C Reference plane (of the solid wheel 1) D1N Bore diameter (of the wheel hub 2) D2a outer hub outer diameter D2i inner hub outer diameter D3 Hub diameter (of construction point K3) D4 Wheel rim inner diameter G1 first straight G2 second straight K1 first construction point K2 second construction point K3 third construction point K4 fourth construction point L2a distance (fourth level X4 - seventh level X7) L2i distance (fourth level X4 - sixth level X6) LC axial distance (between reference plane C and inner side surface X2) LD Running circle diameter MA middle axle (of the solid wheel V) ML median line (of wheel disc 3) RB wheel flange width (axial) RD Wheel rim thickness (radial) RRD remaining wheel rim thickness (radial) S1 Thickness of the wheel disc 3 (adjacent to the wheel rim 1) S2 Thickness of the wheel disc 3 (adjacent to the wheel hub 2) V full wheel VA wear rate x axial direction X1 first plane (axially outer side surface of the wheel rim 1) X2 second plane (axial inner side surface of wheel rim 1) X3 third level (entry level median line ML in wheel rim 1) X4 fourth level (entry level median line ML in wheel hub 2) X5 fifth plane (vertex plane) X6 sixth level (inner hub face) X7 seventh plane (hub outer face) y radial direction Y1 Foot point (of wheel rim 1) α angle

Claims

[1] Solid wheel (V) with high thermal performance for rail vehicles, with: - a radially outer wheel rim (1), - a radially inner wheel hub (2) which runs around a central axis (MA) of the solid wheel (V), and - a wheel disc (3) that connects the wheel rim (1) to the wheel hub (2), - wherein the wheel flange (1) has a running surface (4), a wheel flange (5), an outer side surface in a first plane (X1) and an inner side surface in a second plane (X2), - wherein the first plane (X1) and the second plane (X2) are orthogonal to the central axis (MA), - wherein the wheel rim (1) has a reference plane (C) running orthogonally to the central axis (MA) with a running circle diameter (LD) in the area of ​​its running surface (4), - wherein the reference plane (C) is shifted parallel outwards relative to the second plane (X2) and the inner side surface of the edge ring (1) by an axial distance (LC), wherein the distance (LC) is preferably 50 mm to 80 mm, - wherein the wheel rim (1), the wheel disc (3) and the wheel hub (2) are formed in one piece as a solid wheel (V), and - wherein the wheel disc (3) has a median line (ML) whose course is defined by several construction points (K1, K2, K3, K4), characterized by , that the following conditions apply to the median line (ML) and to the construction points (K1, K2, K3, K4): a) first construction point (K1): - The first construction point (K1) is the intersection of a third plane (X3) running orthogonally to the central axis (MA), which determines the axial position, and a first straight line (G1), which determines the radial position. - The third plane (X3) is shifted parallel inwards relative to the reference plane (C) by an axial distance (A) and passes through the area of ​​the wheel flange (5). - The first straight line (G1) passes through a foot point (Y1) at the radially inner and axially outer corner of the wheel rim (1) and is inclined at an angle (α) between 0° and 14° to a second straight line (G2) that runs parallel to the central axis (MA). - The median line (ML) of the wheel disc (3) runs parallel to the reference plane (C) in the area of ​​the first construction point (K1). b) second construction point (K2): - The second construction point (K2) is the vertex of the median line (ML), i.e. the point of the median line (ML) furthest axially outside. - The second construction point (K2) is the intersection of a fifth plane (X5) running orthogonally to the central axis (MA), which determines the axial position, and a diameter (DK2), which determines the radial position. - The fifth plane (X5) is shifted parallel outwards relative to the reference plane (C) by an axial distance (B). c) third construction point (K3): - The third construction point (K3) is the intersection of a fourth plane (X4) running orthogonally to the central axis (MA), which determines the axial position, and a diameter (D3), which determines the radial position. - The fourth level (X4) lies between the third level (X3) and the fifth level (X5) and is shifted parallel to these two levels. d) fourth construction point (K4): - The fourth construction point (K4) is an inflection point where the curvature direction of the median line (ML) changes, or a point on a straight line adjacent to both ends of which the curvature direction of the median line (ML) changes. [2] Solid wheel (V) according to claim 1, characterized by , that the running circle diameter (LD) is in the range between 600 mm and 1250 mm, in particular between 840 mm and 920 mm. [3] Solid wheel (V) according to claim 1 or claim 2, characterized by , that the thickness (S2) of the wheel disc (3) adjacent to the wheel hub (2) is greater than the thickness (S1) of the wheel disc (3) adjacent to the wheel rim (1), preferably being: 1.05 * S1 ≤ S2 ≤ 1.95 * S1. [4] Solid wheel (V) according to one of claims 1 to 3, characterized by, that the wheel disc (3) between the first design point (K1) and the fourth design point (K4) has a first section (A1) which is curved and preferably has a constant curvature throughout. [5] Solid wheel (V) according to one of claims 1 to 4, characterized by , that the wheel disc (3) has a second section (A2) between the fourth design point (K4) and the second design point (K2), which is curved and preferably has a constant curvature throughout. [6] Solid wheel (V) according to claim 4 or 5, characterized by , that the first section (A1) and the second section (A2) have opposite directions of curvature. [7] Solid wheel (V) according to any one of claims 1 to 6, characterized by, that the wheel disc (3) has between the second construction point (K2) and the third construction point (K3) a third section (A3) adjacent to the second construction point (K2) and a fourth section (A4) adjacent to the third construction point (K3), which have opposite directions of curvature. [8] Solid wheel (V) according to claim 7, characterized by , that the third section (A3) is curved and preferably has a constant curvature throughout. [9] Solid wheel (V) according to claim 7 or 8, characterized by , that the fourth section (A4) is at least section-wise curved and / or at least section-wise straight.

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