Roof Hood for a Rail Vehicle

Abstract

A roof hood for a rail vehicle having side walls and a planar roof, wherein a sloping part is provided at the transition from the side walls to the roof, where the roof hood configured to fasten to the roof of the rail vehicle, is curved upward and extends from the sloping part of one longitudinal side of the rail vehicle to the sloping part of the opposite longitudinal side.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This is a U.S. national stage of application No. PCT / EP2024 / 058627 filed 28 Mar. 2024. Priority is claimed on Austrian Application No. A 50321 / 2023 filed 28 Apr. 2023, the content of which is incorporated herein by reference in its entirety.BACKGROUND OF THE INVENTION1. Field of the Invention

[0002] The invention relates to a roof hood for a rail vehicle for reducing crosswind sensitivity, in particular for a passenger rail vehicle.2. Description of the Related Art

[0003] Rail vehicles are exposed to aerodynamic forces as a result of wind. The effective wind consists of relative wind caused by movement and natural ambient wind. If this wind does not occur as a pure headwind, but as a crosswind with a velocity component perpendicular to the longitudinal axis, then this can cause a rail vehicle to tip over, despite its generally high mass. This danger particularly exists for vehicles with unfavorable aerodynamic properties, for example, a large area exposed to the wind, low weight and high travel speed, due to the superposition of relative wind and ambient wind. In general, the rail vehicle is subject to an aerodynamic resistance force resulting from the headwind, lateral force resulting from the crosswind and lift force resulting from the air flow. In addition, roll, pitch and yaw moments occur due to the uneven aerodynamic force distribution. Crosswind sensitivity is in particular expressed by the roll moment on the vehicle about its longitudinal axis or a tilting moment about the leeward (windward) rail. Lift forces have a secondary effect by reducing the adhesion of the wheels to the rails. One known solution for reducing this sensitivity is to add mass in the area of the underframe. Other known measures involve modifications to the chassis properties to optimize load distribution on both bogies.

[0004] Conventional solutions to this problem focus on aerodynamic measures for improving crosswind stability of high-speed vehicles, in particular on reducing lift at the front of the vehicle. In contrast, conventional vehicles, which typically travel at speeds of up to 200 km / h, and in particular those reinforced for travel speeds of up to 230 km / h, generally have a rectangular car body and therefore exhibit different aerodynamic behavior due to their blunt shape. The car body is often constructed using lightweight construction techniques and this can also lead to increased crosswind sensitivity in these vehicles. Vehicles with a sloping part between a side wall and the roof have proven to be particularly critical in terms of crosswind sensitivity. A large number of vehicles constructed in this way are already in use. Consequently, a solution for retrofitting is also very advantageous, because it allows for responses to changes in weight and an extension of the driving speed range. Furthermore, structural integrity, pressure and resistance and watertightness of a rail vehicle body should not be impaired thereby and expenditure on assembly equipment should be low.SUMMARY OF THE INVENTION

[0005] In view of the foregoing, it is therefore an object of the invention to provide a roof hood for a rail vehicle that reduces crosswind sensitivity, i.e., reduces the resulting tilting moment on the car body caused by crosswinds.

[0006] This and other objects and advantages are achieved in accordance with the invention by a roof hood for a rail vehicle, where the rail vehicle comprises flat side walls and a flat roof, where a sloping part is provided at the transition from the side walls to the roof, and where the roof hood is structured to be fastened to the roof of the rail vehicle and is curved upward and extends from the sloping part of one longitudinal side of the rail vehicle to the sloping part of the opposite longitudinal side.

[0007] A flat roof can also be formed from corrugated sheet metal as is commonly used in rail vehicles, or from sheet metal reinforced with ribs.

[0008] This offers the advantage of being able to positively influence the aerodynamic properties of a rail vehicle with respect to the tilting moment that occurs in crosswinds, so that this tilting moment is reduced at the same flow velocity compared to rail vehicles without a roof hood.

[0009] In accordance with the invention, a roof hood is constructed in the form of a flat component with a curvature configured to be fastened in the roof area of a rail vehicle. The roof hood in accordance with the invention is particularly provided for rail vehicles with flat side walls and a flat roof with a sloping part at the transition from the side walls to the roof. This feature causes disadvantageous crosswind characteristics, which can be improved by a roof hood. A particularly advantageous property of the invention is that the roof hood can also be used to retrofit existing vehicles or vehicles that have already been developed in principle, where only minimal modifications to existing vehicles are required. The roof hood can be used particularly advantageously in train configurations that include a control car with a significantly lower mass than a locomotive, making it more sensitive to crosswinds.

[0010] The roof hood is to be formed as a component with an upward curvature in cross section, where this curvature remains constant along the entire length of the roof hood. In accordance with a first embodiment, the curvature consists of a sequence of at least three radii, where the first and last radius are each attached to a sloping part and the structure is to be symmetrical.

[0011] In a further preferred embodiment of the roof hood, the curvature of the roof hood follows a section of a circumferential line of an ellipse.

[0012] The transition between the sloping part of the car body of the rail vehicle and the roof hood is crucial for optimal functioning of the roof hood. It is particularly advantageous for the inclination of the roof hood to be tangential to that of the sloping part. Herein, sufficiently improved aerodynamic properties can still be provided with a deviation of up to 10° from the tangential direction to the horizontal.

[0013] The provision of transition radii that are too small or, in extreme cases, the provision of a sharp transition between the sloping part and roof will cause the flow to separate in this area on the windward side. This separation inter alia causes a leeward vortex next to the vehicle, which greatly reduces crosswind stability. On the one hand, due to its shape, the provision of a roof hood prevents this separation from occurring but, on the other hand, it exploits the Coanda effect, which causes negative pressure when air flows along a convex geometry. In this case, it occurs on the windward side, thus improving the vehicle's crosswind stability.

[0014] The roof hood can preferably extend over the entire length of the rail vehicle, thereby allowing for particularly advantageous crosswind characteristics. If this is not possible for certain reasons, such as the need for roof superstructures, then the roof hood may only extend over a specific section of the length of the rail vehicle. Particularly in the case of control cars, it is advantageous to arrange the roof hood close to the front side, because this improves the crosswind characteristics of the front of the vehicle, which is particularly sensitive to sidewinds, while leaving the remaining sections of the roof free for roof superstructures, such as pantographs and / or antennas.

[0015] A roof hood can advantageously be a sheet metal structure consisting of frames and bows planked with sheet metal, where further longitudinal stiffeners can be arranged to improve accessibility.

[0016] Furthermore, the aerodynamic properties of a roof hood in accordance with the invention can be improved by providing paneling on its front sides to direct relative wind around the gap between the roof and the underside of the hood. This can prevent disruptive turbulence and noise. Such paneling, which is preferably wedge-shaped, can be molded integrally into the roof hood, or be a separate component.

[0017] It is aerodynamically advantageous for the ends of the roof hood facing the front sides of the rail vehicle to taper in a wedge shape.

[0018] For this purpose, for example, the front of the roof hood can be provided so that it slopes at an acute angle. Alternatively, this front can also be rounded. Such a termination to the roof hood can preferably be formed as a deep-drawn component.

[0019] In a preferred embodiment of the invention, the roof hood is formed in two parts comprising a first partial roof hood and a second partial roof hood, where each partial roof hood is formed separately for fastening to the roof of the rail vehicle and each partial roof hood is attached to a sloping part of the rail vehicle, and where an area of the roof of the rail vehicle remains uncovered by the split roof hood. This offers the advantage of allowing large parts of the roof to remain unchanged so that roof superstructures, such as antennas, can continue to be provided without any changes. The aerodynamic properties of such a split roof hood are only slightly worse than those of a continuous roof hood and are significantly better than those of vehicles without this aerodynamic aid.

[0020] Such a split roof hood can be particularly advantageous for retrofitting existing rail vehicles, because it only needs to be arranged in the area of the transition from the sloping part of the side wall to the roof. However, roof superstructures are not commonly arranged at this position, so they do not need to be considered.

[0021] Such partial roof hoods can particularly advantageously be arranged on roofs made of corrugated sheet metal (or sheet metal reinforced with ribs). The partial roof hood can then be pulled over the ribs of a sloping part as far as a rib of the flat roof. The ribs then close off the partial roof hood at the sides.

[0022] The roof hood can be made from all materials commonly used in rail vehicle construction, such as steel, stainless steel or light metal. Likewise, it can also be made of plastic, for example, glass fiber reinforced plastic. The roof hood is preferably fastened with very little interference to the vehicle structure, in particular avoiding recesses and drill holes in the outer skin of the rail vehicle. Although screw connections, rivet connections or similar types of connection are possible, adhesive or welded connections are preferable in terms of ensuring long-term tightness of the vehicle outer skin. A free air passage must be provided in the gap between the underside of the roof hood and the roof so that this ventilation reduces the accumulation of water and the associated risk of corrosion.

[0023] A further option for implementing a roof hood or partial roof hood is to use solid plastic elements. These can be precisely adapted to the outer contour of the rail vehicle with their inner contour facing the rail vehicle, thus eliminating problems with water ingress, thermal expansion of air in a closed cavity and electrical grounding.

[0024] Alternatively, the area between a partial roof hood and the roof of a rail vehicle can be filled with foam. A foam with hydrophobic properties that does not expand upon curing should be used for this purpose.

[0025] A roof hood can, for example, be fastened via at least two C-rails, which are arranged parallel to the longitudinal axis of the rail vehicle on the roof and into which sliding nuts can be inserted. For this purpose, the roof hood itself has corresponding holes through which screw connections can be established. It is essential to close these holes appropriately after establishing a screw connection so that the pressure field acting on the rail vehicle remains undisturbed and the advantageous aerodynamic effect of a roof hood is not reduced.

[0026] Alternatively, the roof hood can also be fastened via brackets, braces or suitable holders.

[0027] However, modern bonding methods also enable a roof hood to be fastened exclusively via adhesive connections. Adhesive connections generally have an electrically insulating effect. Accordingly, appropriate measures, such as grounding strips, must be provided to ground the roof hood to the rail vehicle car body. In addition to an adhesive connection, it is particularly advantageous for the roof hood also to be connected to the car body via screw connections, because this ensures the electrical ground connection.

[0028] In a preferred embodiment of the invention, the roof is made of multi-bent sheet metal, so that the radii in the cross section of the roof hood are approximated by a polygonal chain. The production of a continuously bent sheet with a plurality of consecutive radii is complex. Consequently, a roof hood can be produced more simply and cost-effectively in this way. Herein, the bending points should be positioned close enough to one another such that a polygonal metal sheet can achieve virtually the same aerodynamic effect as continuously bent sheet metal.

[0029] Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims. It should be further understood that the drawings are not necessarily drawn to scale and that, unless otherwise indicated, they are merely intended to conceptually illustrate the structures and procedures described herein.BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Exemplary embodiments of the invention are described in detail below with reference to the accompanying figures, in which:

[0031] FIG. 1 shows A rail vehicle car body with roof hood in accordance with the invention;

[0032] FIG. 2 shows a rail vehicle car body with split roof hood in accordance with the invention;

[0033] FIG. 3 shows a sectional view of a rail vehicle roof with split roof hood in accordance with the invention; and

[0034] FIG. 4 shows a rail vehicle roof with roof hoods of different curvature in accordance with the invention.DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

[0035] FIG. 1 shows by way of example a schematic representation of a rail vehicle car body with a roof hood. Here, an oblique view of a cross section through a rail vehicle roof is depicted, where sloping parts 3 are attached to both sides at the upper end of the side walls and form the transition to a flat roof 2. The rail vehicle shown by way of example is constructed differently than a planked bow-and-frame structure. A “trapezoidal” sheet metal sheet, which is more stable than flat sheet metal, is provided as planking. The kink in the course of the planking at the point of transition from the sloping part 3 in the flat roof 2 is disadvantageous for the aerodynamic properties of such a car body in terms of its crosswind sensitivity. In the exemplary illustrated embodiment, this is improved by providing a roof hood 1. The roof hood 1 is curved upward and extends from the sloping part 3 of one longitudinal side of the rail vehicle to the sloping part 3 of the opposite longitudinal side. Herein, the roof hood 1 is shaped so that its slope is tangential to the sloping part 3. Two C-rails 5 are arranged on the roof 2, via which screw connections 7 are established between the roof 2 and the roof hood 1. The roof hood 1 shown in FIG. 1 spans the entire width of the roof 2 thus complicating the provision of roof superstructures, such as antennas. This problem can be solved by creating recesses in the roof hood 1 through which these roof superstructures can penetrate the roof hood 1. It is essential to seal the holes for the screw connections 7 tightly after they have been established in order to ensure the aerodynamic effect of the roof hood 1.

[0036] To improve tightness between the roof hood 1 and the sloping part 3, the lateral runners of the sheet metal of the roof hood 1 can press against the roof when the screw connections 7 are established, thus ensuring tightness of this connection point.

[0037] FIG. 2 shows by way of example a schematic representation of a rail vehicle roof with a split roof hood. This depicts a detail of a car body of a rail vehicle at the point of transition from a sloping part 3 to a flat roof 2, where a partial roof hood 4 is arranged at this position. Such a partial roof hood 4 is also provided at the opposite point of transition along the opposite longitudinal side of the car body. For purposes of clarity, FIG. 2 only depicts one side. The partial roof hood 4, i.e., the inclination of the partial roof hood 4, is tangential to the sloping part 3 and subsequently extends over the flat roof 2. The flat roof 2 is then uncovered and thus any roof superstructures provided are not impaired by the partial roof hoods 4. The aerodynamic effect of two partial roof hoods 4 is slightly reduced compared to a continuous roof hood 1, as depicted in FIG. 1, but significantly improved compared to a car body without such aerodynamic aids. The exemplary illustrated embodiment shows a partial roof hood 4 that is connected to the sloping part 3 and the roof 2 via adhesive connections 6. A C-rail 5 is arranged on the roof 2, where the partial roof hood 4 is secured against falling off via screw connections 7 and an electrically conductive connection is established between the partial roof hood 4 and the roof 2. This grounding connection is not necessary for partial roof hoods made of plastic. It is essential to have a tight adhesive connection 6 between the partial roof hood 4 and the sloping part 3 so that no air flow can penetrate the gap between the partial roof hood 4 and the car body because this can lead to increased noise and impaired aerodynamic properties. To drain water from the cavity between the rail vehicle roof and the roof hood and to equalize pressure due to thermal expansion of the air, openings should therefore preferably be arranged on the front side.

[0038] FIG. 3 shows by way of example a schematic representation of a rail vehicle roof with a split roof hood in a sectional view. This depicts the exemplary embodiment in FIG. 2 with partial roof hoods 4, where the sectional view is transverse to the longitudinal direction of the car body. Herein, in particular the positions of the adhesive points 6 and the screw connections 7 in relation to the roof 2 are clearly visible. A partial roof hood 4 in accordance with the invention can be made in one piece from sheet metal and, in contrast to a non-split roof hood 1, as shown in the exemplary embodiment in FIG. 1, does not require a support structure made of frames and / or bows.

[0039] FIG. 4 shows by way of example a schematic representation of a rail vehicle roof with two roof hoods of different curvature. The point of transition between a sloping part 3 and a roof 2 is depicted in abstracted form, where both roof hoods have an identical radius of the middle part 3. The curvature of the roof hoods differs at the transition to the sloping part 3. The first roof hood is attached tangentially to the sloping part 3 so that its first radius R1 follows the tangent T. The second roof hood has a second radius R2 at this point of transition that follows a line T-10° that is 10 degrees flatter than the horizontal.

[0040] Thus, while there have been shown, described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements that perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and / or elements shown and / or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.

Claims

1. -11. (canceled)12. A roof hood for a rail vehicle comprising:flat side walls; anda flat roof;wherein a sloping part is provided at a transition from the side walls to the roof,wherein the roof hood is configured to be fastened to the flat roof of the rail vehicle, is curved upward and extends from the sloping part of one longitudinal side of the rail vehicle to the sloping part of an opposite longitudinal side; andwherein an inclination of the roof hood at a connection point to the sloping part is connected to the sloping part between a tangential direction and up to 10° from the tangential direction to a horizontal.

13. The roof hood for a rail vehicle as claimed in claim 12, wherein the curvature of the roof hood follows a sequence of at least three radii; and wherein a first and third radius, which are each attached to a sloping part, are identical, such that the roof hood has a symmetrical cross section.

14. The roof hood for a rail vehicle as claimed in claim 12, wherein the curvature of the roof hood follows a section of a circumferential line of an ellipse.

15. The roof hood for a rail vehicle as claimed in claim 13, wherein the curvature of the roof hood follows a section of a circumferential line of an ellipse.

16. The roof hood for a rail vehicle as claimed in claim 12, wherein the roof hood is formed in two parts comprising a first partial roof hood and a second partial roof hood; wherein each partial roof hood (4) is formed separately for fastening to the roof of the rail vehicle and each partial roof hood is attached to a sloping part of the rail vehicle; and wherein an area of the roof of the rail vehicle remains uncovered by a split roof hood.

17. The roof hood for a rail vehicle as claimed in claim 13, wherein the roof hood is formed in two parts comprising a first partial roof hood and a second partial roof hood; wherein each partial roof hood is formed separately for fastening to the roof of the rail vehicle and each partial roof hood is attached to a sloping part of the rail vehicle; and wherein an area of the roof of the rail vehicle remains uncovered by a split roof hood.

18. The roof hood for a rail vehicle as claimed in claim 14, wherein the roof hood is formed in two parts comprising a first partial roof hood and a second partial roof hood; wherein each partial roof hood is formed separately for fastening to the roof of the rail vehicle and each partial roof hood is attached to a sloping part of the rail vehicle; and wherein an area of the roof of the rail vehicle remains uncovered by a split roof hood.

19. The roof hood for a rail vehicle as claimed in claim 12, wherein the roof hood is a sheet metal structure made of frames and bows planked with sheet metal.

20. The roof hood for a rail vehicle as claimed in claim 12, wherein the curvature of the roof hood is approximated via polygonization from multi-bent sheet metal.

21. The roof hood for a rail vehicle as claimed in claim 12, wherein an ends of the roof hood facing front sides of the rail vehicle taper in a wedge shape.

22. A rail vehicle comprising:flat side walls; anda flat roof;wherein a sloping part is provided at a transition from the flat side walls to the flat roof;wherein at least two C-rails are arranged on the flat roof parallel to a longitudinal axis of the rail vehicle for fastening a roof hood.

23. The rail vehicle comprising the roof hood as claimed in one of claim 12, wherein the roof hood extends over an entire length of the rail vehicle.

24. The rail vehicle comprising a roof hood as claimed in claim 12, wherein the roof hood extends over a specific section of a length of the rail vehicle.

25. The rail vehicle as claimed in claim 22, wherein the rail vehicle is a control car.

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