Railway vehicle with wireless grounding

Abstract

In a rail vehicle (1) designed to travel on rails, comprising a frame (3), a chassis held on the frame (3), and a component or assembly designated as the superstructure (2) which is mechanically fastened to the frame (3) by means of bolts (5), wherein contact surfaces are provided in the area of ​​the bolts (5) at which the superstructure (2) contacts the frame (3), and wherein the superstructure (2) is electrically connected to the frame (3) in such a way that the superstructure (2) is grounded via the frame (3), the chassis and the rails, the invention proposes that contact elements made of an electrically conductive, corrosion-resistant material are arranged in the area of ​​the contact surfaces on both the superstructure (2) and the frame (3) in such a way that the contact elements are electrically pressed together by means of the bolts (5), wherein the contact elements connect electrically to the superstructure (2) or frame (3).

Description

[0001] The invention relates to a rail vehicle according to the preamble of claim 1.

[0002] Standard rail vehicles are well-known in practice. The frame refers to the elements of the rail vehicle's supporting structure, while the superstructure refers to the components, assemblies, or modules attached to this supporting structure. Fastening is achieved using bolts, such as rivets or typically screws. The running gear, also attached to the supporting structure, refers to the elements of the rail vehicle located between the supporting structure and the rails on which the rail vehicle travels.

[0003] In principle, all components of a rail vehicle must be grounded. Particularly stringent requirements apply to the grounding of superstructures where there is an increased probability that a potentially broken and live overhead line could fall onto such modules or assemblies. Therefore, in known rail vehicles, the superstructures are connected to the frame via grounding cables, which are bolted to the respective element of the rail vehicle at at least one or both of their ends. Since the rails, the undercarriage, and the frame are all made of steel—i.e., electrically conductive materials—grounding of the superstructure is ensured by means of the grounding cables, as an electrically conductive connection is established from the superstructure, through the frame and the undercarriage, to the rails, and then via the rails to the ground.

[0004] Depending on the requirements, the grounding cables have effective cross-sections of 95 mm² or more. The problem is that metal thieves can remove these grounding cables from the rail vehicle. Since, apart from the compromised grounding, the rail vehicle remains fully functional, there is a risk that the removal of the grounding cables will go unnoticed. Furthermore, there is a risk that the rail vehicle will continue to be used even after the loss of the grounding cables has been discovered, ultimately exposing the train's personnel to increased danger.

[0005] From DE 196 03 511 A1, a car body of a rail vehicle is known which is specially equipped with so-called grounding components. The grounding components each have a grounding holder, which is designed in the form of a bracket and to which a grounding cable, referred to as a grounding rope, can be screwed.

[0006] From DE 10 2011 051 137 A1, a fastening element is known which consists of a blind rivet nut and a screwed-in fastening screw. Grounding lugs at the ends of grounding cables are clamped between the blind rivet nut and the head of the fastening screw. The screw is not used for fastening the components, but the fastening element serves to create an electrical grounding point, i.e., to electrically connect the grounding lugs to a sheet metal or other component of a motor vehicle, particularly in the case of repairs, to replace broken ground studs.

[0007] German patent DE 29601672 U1 discloses a rail vehicle car body with grounding components. These grounding components are intended for grounding electrical components to the car body shell. As is common practice in rail vehicle construction, the electrical components are grounded using grounding cables that are connected to the grounding components by screws. For corrosion protection, a stainless steel threaded insert may be incorporated in the grounding holder, which serves to screw in such a grounding cable. Further reference to the prior art can be made to CN 208 489 367 U.

[0008] The invention is based on the objective of improving a generic rail vehicle in such a way that it enables reliable and permanently secured grounding.

[0009] This problem is solved by a rail vehicle with the features of claim 1. Advantageous embodiments are described in the dependent claims.

[0010] In other words, the invention proposes not to use external, separate grounding cables, but rather to provide contact elements made of an electrically conductive and corrosion-resistant material where contact surfaces already exist. This applies, for example, to the points where the superstructure is connected to the frame or the frame to the chassis. In this context, corrosion-resistant means that the contact elements are protected against corrosion not only at the time of installation, but also fundamentally due to their material properties under the conditions encountered during the operation of the rail vehicle. Protection against corrosion in this context means that the contact element in question is not destroyed by corrosion.

[0011] Additional components, such as the aforementioned grounding elements and grounding brackets known from rail vehicles, which are designed for use with grounding cables in a known manner, can therefore be omitted as proposed. The present proposal does not require an additional grounding console. Instead, the existing contact surface required to attach the superstructure to the vehicle frame is used for grounding the components.

[0012] The specially designed fastening elements mentioned above, which are intended to allow the electrically conductive connection of grounding lugs instead of a ground bolt and are therefore also designed for use with grounding cables, can also be omitted. Instead, the existing mounting points where the superstructure is attached to the vehicle frame are used for grounding the components. No components of the bolted connection, such as a blind rivet nut and a screwed-in fastening bolt, are used for grounding; rather, the aforementioned contact surfaces where the superstructure rests on the vehicle frame are used. An advantage of this design is that any liquids penetrating the bolted connection cannot affect the grounding. Therefore, corrosion-resistant bolts are not required, allowing the use of higher-strength bolts, unlike, for example, stainless steel bolted connections.The screws are used for the intended fastening of the components anyway, and the grounding is a desired "side effect" that saves components, simplifies the manufacture of the rail vehicle and makes the grounding more reliable, because, for example, grounding cables that could be torn off are not present in the first place.

[0013] According to the invention, the contact elements are pressed together in an electrically conductive manner by means of bolts at the connection points, for example where the structure is connected to the frame, so that as a result the contact surfaces are held in an electrically conductive contact by means of the bolts.

[0014] Finally, according to the invention, it is further provided that the contact elements also connect electrically to the component of the rail vehicle to which they are attached, i.e., are electrically conductively connected either to the superstructure or to the frame.

[0015] The inventive design of the rail vehicle simplifies, firstly, the assembly of the rail vehicle, since the grounding is automatically ensured simultaneously with the necessary attachment of the superstructure to the frame, without requiring additional assembly steps such as the installation of a grounding cable. Secondly, grounding of the superstructure is ensured as long as it is attached to the frame of the rail vehicle. Thirdly, the rail vehicle is better protected against vandalism, since no separate grounding cables are used that could be removed. The contact elements are well protected in the area of ​​the connection points where the superstructure is connected to the frame of the rail vehicle by means of bolts.This improved vandalism protection enhances the safety of the train's personnel and reduces the otherwise necessary maintenance effort that would arise from the required replacement of grounding cables.

[0016] With an otherwise fundamentally unchanged design of a rail vehicle, the rail vehicle can be designed according to the invention by providing stainless steel sheets on the frame and on the superstructure in the area of ​​fastening points, for example, screw connections. These sheets come into contact with each other when the superstructure is connected to the frame at the fastening points. The fastening of the superstructure to the frame using screws is mentioned here only as an example, without limiting the invention to the design of the bolts as screws.

[0017] In one embodiment, particularly reliable contact is achieved by inserting an electrically conductive sleeve into a bore in the frame, which is designed to receive the bolts. This sleeve forms the contact element of the frame. It is particularly advantageous to have such sleeves as contact elements at all screw connections where the structure is attached to the frame. The sleeve has an inner diameter large enough to allow the bolt to be inserted into and pass through it. The sleeve is electrically connected to the frame. The contact pressure applied during the screw connection process ensures excellent electrical contact between the bolt and the sleeve for grounding purposes.

[0018] To ensure optimal electrical contact between the sleeve and the frame, the frame is preferably free of any surface coating in the area where it contacts the sleeve. To prevent corrosion of the frame in this area, which could undesirably increase the electrical resistance between the sleeve and the frame, the sleeve advantageously connects to the frame at both ends in a watertight manner. The sleeve can, for example, be welded into the frame of the rail vehicle so that it connects to the frame at both ends in a watertight and electrically conductive way. Alternatively, separate sealing elements such as O-rings or the like can be used, but especially electrically conductive sealing elements such as copper rings.

[0019] The corrosion-resistant contact elements can, for example, consist of an aluminum or copper alloy, which, due to its aluminum or copper content, can exhibit excellent electrical conductivity. While such materials as aluminum or copper oxidize, just like steel, and are therefore not ultimately corrosion-free, they form an oxide layer on their surface that protects the surrounding material from further oxidation. Thus, these materials are corrosion-resistant in the sense of this proposal. In contrast, the oxide layer known as rust on most types of steel does not form such a protective layer. Consequently, in most steel alloys, the rusting component is destroyed by the rust and is therefore neither corrosion-free nor corrosion-resistant.

[0020] In particular, an aluminum and copper-containing design of the contact elements can consist of an aluminum base component – ​​e.g., a plate – being electroplated with a copper-containing surface layer, which, for example, can have a layer thickness of approximately 1 mm. Such an aluminum component can be used, for instance, when it is to be welded as a contact element to a vehicle component that is also made of aluminum, as may be the case for body components, such as a platform, for weight reasons. In this case, the copper coating can be mechanically removed where the contact element is to be welded to the vehicle component, thus enabling this welding process without problems.

[0021] The contact elements can preferably be made of a non-corrosive stainless steel alloy, so that the contact element is both corrosion-resistant and corrosion-free. This ensures good electrical conductivity, which is maintained throughout the entire service life, since no oxide layer forms on the surface of the stainless steel contact element that would have different electrical properties than the base material beneath the surface.

[0022] Good electrical contact between the sleeve and the frame can be achieved by the sleeve making electrically conductive contact with the frame along its circumference. For example, the sleeve can be pressed into the bore of the frame.

[0023] Advantageously, the sleeve can have a circumferential collar on the side facing the superstructure, so that the largest possible contact area is provided on the frame of the rail vehicle, to which a corresponding contact area of ​​the superstructure can be applied when the superstructure is connected to the frame.

[0024] In one embodiment, the aforementioned sleeves can be omitted and the number of components reduced if a plate forms the frame-side contact element. The plate is placed on the frame, thus replacing the collar of one of the aforementioned sleeves that would otherwise rest on the frame. The plate can be large enough to extend over two or more bores arranged in the frame to accommodate the bolts, allowing several sleeves to be replaced by this single plate. With a suitable material selection, the plate can be welded to the frame all around, preventing moisture from penetrating underneath and thus protecting the inner surfaces of the bolt holes from corrosion.

[0025] An embodiment of the invention is explained in more detail below with reference to the purely schematic representation.

[0026] The drawing shows a section of a rail vehicle 1, in the form of a vertical section through the area of ​​two bolted connections where a superstructure 2 is attached to a frame 3 of the rail vehicle 1. The superstructure 2 could, for example, be the housing of a specific unit, or it could be a mounting bracket that is part of a larger component. This mounting bracket is a welded construction and has a cross-section similar to an I-beam. The depicted area of ​​the frame 3 could, for example, be the top flange of a vehicle frame.

[0027] The frame 3 has a bore 4 at each of the two screw points. The diameter of the bore 4 is dimensioned to provide clearance around a bolt 5. In the illustrated embodiment, the bolts 5 are designed as screws. Between a nut 7 and the frame 3, and between the screw head of the bolt 5 and the adjacent section of the structure 2 located below the screw head, intermediate washers 6 and 8 made of different materials are arranged. These washers serve to distribute the load and also to seal, so that, for example, the surface of the frame 3 in the area of ​​the bore 4 is sealed downwards by the intermediate washers 6.

[0028] A plate 10 is located on the top side of the frame 3, i.e., towards the structure 2, thus providing a large contact area. The plate 10 can be welded to the frame 3 along its outer circumference to ensure a watertight connection between the plate 10 and the frame 3, thereby protecting the inner surfaces of the bores 4 from corrosion.

[0029] Plate 10 represents a contact element of the frame 3, to which an electrically conductive contact element of the superstructure 2, designed as plate 9, rests. Both plates 9 and 10 are made of stainless steel and are therefore corrosion-resistant. Plate 9 has bores through which the two bolts 5 extend, so that when the bolting is completed, the contact elements of the superstructure 2 and the frame 3, namely plates 9 and 10, are pressed together and create an electrically conductive connection that forms part of the grounding system of the rail vehicle 1. Reference symbol:

[0030] 1 Rail vehicle 2 Superstructure 3 Frame 4 Bore 5 Bolt 6 Washer 7 Nut 8 Washer 9 Plate 10 Plate

Claims

1. Rail vehicle (1) which is intended to run on rails, comprising a frame (3), a chassis mounted on the frame (3), and comprising a component or an assembly which is referred to as a superstructure (2) and is mechanically secured on the frame (3) by way of bolts (5), wherein there are contact surfaces in the region of each of the bolts (5), the superstructure (2) contacting the frame (3) at each of the contact surfaces, and wherein the superstructure (2) is electrically conductively connected to the frame (3) in such a way that the superstructure (2) is earthed via the frame (3), the chassis and the rails, characterized in that contact elements composed of an electrically conductive, corrosion-resistant material are arranged in the region of the contact surfaces both on the superstructure (2) and on the frame (3) in such a way that the contact elements are electrically conductively pressed against each other by way of the bolts (5), wherein the contact elements are each electrically conductively connected to the superstructure (2) or frame (3) to which they are secured.

2. Rail vehicle according to Claim 1, characterized in that a frame-side contact element is configured as an electrically conductive sleeve which is arranged in a hole (4) in the frame (3) intended for receiving a bolt (5), wherein the inside diameter of the sleeve is dimensioned to allow for the bolt (5) to be received, and the sleeve is electrically conductively connected to the frame (3), wherein the sleeve, along its circumference, electrically conductively contacts the frame (3) and, on its side facing the superstructure (2), has an encircling collar (10).

3. Rail vehicle according to Claim 2, characterized in that the sleeve is connected to the frame (3) in a watertight manner at both of its ends.

4. Rail vehicle according to any of the preceding claims, characterized in that the contact elements consist of a stainless steel alloy.

5. Rail vehicle according to Claim 2, characterized in that the sleeve is screwed into the frame (3).

6. Rail vehicle according to Claim 1, characterized in that a frame-side contact element is configured as an electrically conductive plate (10) which has a hole (4) intended for a bolt (5) to pass through, wherein the plate (10) is electrically conductively connected to the frame (3).