Wheelset AXLE protection device and method of manufacturing such

Abstract

The present invention relates to a process for manufacturing protection device for protecting a wheelset axle of a rail vehicle, wherein semi-finished products made of vulcanized layers of ballistic protection high performance fiber (e.g., ultra-high-molecular-weight polyethylene (UHMWPE) such as Dyneema®, or aramid or fiberglass-reinforced plastic) are processed in an autoclave as raw half-shells with a width of a UHMWPE web (e.g., 1600mm) and with a semicircular arc (e.g., > 180°). The raw half-shells are then subjected to a cutting process to produce various prefabricated half-shells of different sizes (e.g., long, medium and short) from one raw shell, which is not possible in a conventional pressing process. The obtained protection device comprises sectional shells (e.g., half-shells) made of vulcanized layers of the ballistic protection high performance fiber in combination with a metallic outer shell for protection against impact loads of relatively heavy gravel stones, e.g., prevention of damage to a wheel shaft.

Description

[0001] WHEELSET AXLE PROTECTION DEVICE AND METHOD OF MANUFACTURING SUCH

[0002] Field

[0003] The present application relates to a protection device for protecting a wheelset axle of a rail vehicle or other vehicle and a method of manufacturing such a protection device.

[0004] Rail vehicles generally comprise a car body and a plurality of bogies that support the car body. Such bogies may have a plurality of wheelsets, each wheelset comprising two rail wheels and one axle connecting the wheels together. While the rail vehicle is traveling, the wheelset axles may be exposed to collisions with objects such as gravel stones, rocks or ice. Such collisions may cause damage to the wheelset axle and in particular to its paintwork or coating, thus resulting in corrosion of the axle material and in cracking. Therefore, wheelset axles need to undergo time-consuming and expensive repair and / or maintenance operations.

[0005] Therefore, time-consuming coating has been applied on the wheelset axles to protect them against damage from colliding objects. Also, baffle plates have been proposed, which may be attached to a traction motor, a bogie frame and / or a bogie gearbox. These known protection measures are inadequate, however, when it comes to ensuring effective protection of the wheelset axle from collision-related damage.

[0006] The DE102010009437A discloses a wheelset axle protection device for train speeds up to about 200km / h, which comprises an elastomeric mat, that can be easily placed on the wheelset axle, and retaining means for retaining the elastomeric mat on the wheelset axle.

[0007] However, protection of the above known elastomeric mat was meanwhile determined to be insufficient for higher speeds of modern trains up to 400km / h, which means double momentum (m*v) and fourfold energy (m / 2*v2) of the impact of gravel stones. Summary

[0008] It is therefore an object of the invention to provide an improved protection device that provides more effective protection of the wheelset axle for higher train speeds without substantially changing size and weight of the protection device.

[0009] The present invention addresses the above-mentioned object by providing a manufacturing method as claimed in claim 1 and a device as claimed in claim 8.

[0010] According to a first aspect, a method of manufacturing a device for protecting a wheelset axle of a rail vehicle is provided, the method comprising: placing a layered structure including a plurality of layers of ballistic protection high performance fiber, in particular ultra-high-molecular-weight polyethylene, UHMWPE, or aramid or fiberglass-reinforced plastic, on a winding tube with a size adapted to the outer shape of the wheelset axle; processing the plurality of UHMWPE layers on the winding tube in a pressure vessel, in particular an autoclave, to obtain a laminated raw sectional shell of the device; and cutting the raw sectional shell into a predetermined length that is adapted to the length of the wheelset axle.

[0011] According to a second aspect, a device for protecting a wheelset axle of a rail vehicle is provided, the device comprising two or more sectional shells made of vulcanized layers of ballistic protection high performance fiber, in particular ultra-high-molecular- weight polyethylene (UHMWPE) or aramid or fiberglass-reinforced plastic, to be placed around the wheelset axle, and a metallic housing (made of e.g., stainless steel (e.g., EN 1.4301), aluminium or titan) arranged to enclose the sectional shells.

[0012] Accordingly, the proposed manufacturing process allows producing semi-finished products in a pressure vessel (e.g., an autoclave) as raw sectional shells (e.g., with a width of a high performance fiber (e.g., UHMWPE) web and a sectional circular arc or other bend or curved shape adapted to the shape of the wheelset axle), and then using them to produce various sectional shells by exact cutting. As a result, several prefabricated sectional shells can be produced from one raw shell, which is not possible in a conventional press.

[0013] The two or more sectional shells allow the use of shell material with less flexibility or elasticity compared to full circular or at least more than half-circular shell shapes. Thereby, protection efficiency of the shell material can be improved. For example, harder ballistic protection high performance fiber materials, such as ultra-high-molecu- lar-weight polyethylene (UHMWPE), can be used that provides extraordinary protection against colliding objects. The UHMWPE material of the sectional shells surprisingly provides non-expectable different ballistic performance values that become noticeable under very high impact loads only. This prevents damage to the wheelset axle at very high speed up to 400km / h, such that the service life and in particular the costs of maintaining the wheelset axle are reduced. At the same time, the dimensions (i.e., length, width and thickness) of the sectional shells may easily be adapted to the wheelset geometry. Direct contact between colliding objects and wheelset axle is thus prevented with higher protection strength.

[0014] Additionally, for a proper interception process, the metallic housing (made of e.g. stainless steel, titanium or aluminium) with two outer half-walls is necessary. In the event of an impact, the object, e.g. granite stone or chunks of ice, must not penetrate, but must be caught with a dent. Therefore, a ballistic hard shell (sectional shell) must be arranged behind the outer shell, which absorbs the momentum and generates so much resistance, in conjunction with the massive wheelset shaft, so that the object is cushioned or disassembled. The outer wall (i.e., first shell) should not crack in a temperature range of -50°C to + 50°C.

[0015] Throughout the present disclosure the term "ballistic protection high performance fiber" is to be understood as a material comprising polymeric-based high-performance fibers selected from e.g. a para-aramid group (e.g., Kevlar® and Twaron®), UHMWPE (e.g., Spectra®, Dyneema®, and Technora®), liquid-crystal polymer (LCP) fibers (e.g., Zylon® and Vectran®), and fiberglass (e.g., E, S, R glass) with their advantages of lightweight and high strength.

[0016] The proposed device can easily be mounted on the wheelset axle, without significant amounts of labour. Demounting the device may also be performed in minimal time.

[0017] With the proposed wheel shaft protection device, a combination of materials has been found that enables wheel shaft protection up to a train speed of 400km / h, while weight and dimensions of previous conventional protection devices can be maintained to ensure compatibility with the existing trains. The sectional shells of ballistic protection high performance fiber in combination with the metallic outer shell (e.g., sheet metal such as stainless steel) provides substantially improved protection against impact loads of relatively heavy gravel stones.

[0018] Bandage fixation systems are advantageous as the retaining means. These are cheap to obtain and allow rapid attachment of the device to the wheelset axle with little radial thickness. In this case, the retaining means fully encircle the sectional shells and optionally a housing.

[0019] According to a first option that can be combined with above first or second aspect, the device may comprise two half-shells and two portions of the metallic housing to be placed around the wheelset axle. Thereby, mounting and demounting of the metallic outer shell and the half-shells can be facilitated while ensuring proper stability and protection.

[0020] According to a second option that can be combined with the first option or the above first or second aspect, retaining means may be provided and configured to retain the sectional shells and the metallic housing when mounted on the wheelset axle.

[0021] According to a third option, the retaining means may comprise a bandage fixation system with closing elements submerged in the metallic housing. Thereby, the radial dimensions of the device after mounting can be reduced to better fit into the available space around the wheelset axle.

[0022] According to a fourth option that can be combined with any one of the first to third options or the above first or second aspect, the sectional shells to be placed around the wheelset axle may be made of Dyneema® HB24 or HB26 layers.

[0023] According to a fifth option that can be combined with any one of the first to fourth options or with the first or second aspect, the sectional shells may each have a radial thickness of 3mm and the metallic housing may have a radial thickness of 2mm.

[0024] According to a sixth option that can be combined with any one of the first to fifth options or with the first or second aspect, the placing step of the manufacturing process may comprise placing a pressure metal plate on top of the layered structure.

[0025] According to a seventh option that can be combined with the sixth option, the manufacturing process may further comprise placing an air ventilation fabric on top of the pressure metal plate.

[0026] According to an eighth option that can be combined with any one of the first to seventh options or with the above first or second aspect, the manufacturing process may further comprise wrapping the winding tube with the layered structure in a vacuum film that is sealed airtight.

[0027] According to a ninth option that can be combined with any one of the first to eighth options or with the above first or second aspect, the manufacturing process may further comprise placing the laminated raw sectional shell on a matched holding device with a plurality of cutting gaps adapted to predetermined lengths of the wheelset axle.

[0028] According to a tenth option that can be combined with any one of the first to ninth options or with the above first or second aspect, the manufacturing process may further comprise applying a suction force to a holding section of the holding device to fix the laminated raw sectional shell on a matched holding device.

[0029] According to an eleventh option that can be combined with any one of the first to tenth options or with the above first or second aspect, the manufacturing process may further comprise widening longitudinal ends of a cut sectional shell in a press mould or by providing a corresponding surface shape on the winding tube.

[0030] It shall be understood that a preferred embodiment of the invention can also be any combination of the dependent claims or above embodiments with the respective independent claim.

[0031] These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter.

[0032] Brief of the

[0033] Further exemplary embodiments and advantages of the invention are presented in the following description of exemplary embodiments of the invention with reference to the figures of the drawings, in which identical reference numerals refer to identically acting components and in which:

[0034] Fig. 1 schematically shows a cross-sectional view of a protection device according a first embodiment;

[0035] Fig. 2 schematically shows a perspective view of a protection device according to a second embodiment;

[0036] Figs. 3A to 3C schematically show perspective views of a bandage fixation system with submerged closing elements for use in various embodiments; Fig. 4 schematically shows a side view and a front view of a first example of a halfshell of the protection device according to various embodiments;

[0037] Fig. 5 schematically shows a perspective view of a second example of a half-shell of the protection device according to various embodiments;

[0038] Fig. 6 shows a flow diagram of a manufacturing process of a protection device according to various embodiments;

[0039] Fig. 7 schematically shows a cross-sectional view of an autoclave for use in the manufacturing process of Fig. 6; and

[0040] Figs. 8A to 8C schematically show perspective side views of a matched holding device for accommodating a raw half shell during a cutting process of the manufacturing process of Fig. 6.

[0041] Detailed Description

[0042] In the following, embodiments of the present invention are described in more detail based on a cylindrical protection device for wheelset axles and a method of manufacturing such a protection device. However, the present invention can be applied to various other types of protection devices for other objects.

[0043] An underlying aim was to find a combination of materials that would enable wheelset axle protection up to a train speed of 400km / h, while the dimensions should be maintained to ensure compatibility with existing trains. New high-speed trains would not allow for larger dimensions and weights.

[0044] In an example, trailer wheelsets of a target train may allow for a maximum height and thus a maximum radial thickness of the protection of 12mm including fixing components (retaining means). Furthermore, motor wheelsets of the target train may allow for a maximum height and thus a maximum radial thickness of the protection of 9mm including fixing components. Thus, the above improved protection must be provided under the above height restrictions.

[0045] Furthermore, as regards longitudinal and circumferential fixation of the protection device on the wheelset axle, sufficient elasticity / rigidity against technological, respectively geometrical tolerances (e.g., +2 / 0mm of the wheelset axle diameter) between the interfaces of the fixing components needs to be provided. Moreover, a maximum mass of a segment of the protection device (e.g., 5kg for U-shaped segments, 10kg for C- shaped segments) and / or a maximum surface-specific mass of a segment (e.g., 18,9kg / m2)needs to be considered.

[0046] The inventors needed to carry out huge numbers of ballistic load tests with ceramic balls and original gravel stones until they surprisingly verified that the above aim can be achieved by replacing the initially described flexible elastomeric mat with solid circular segment shells (e.g., half shells) of ballistic protection high performance fiber material of the same thickness (e.g., 3mm). In general, for proper protection and based on the type of ballistic protection high performance fiber material, the thickness may range between 3mm and 6mm, more specifically 3 to 6mm for UHMWPE and aramid and 2 to 4mm for fiberglass.

[0047] Embodiments are configured to ensure that the outer metallic shell or housing is not penetrated in the event of an impact. Therefore, with a thin metal shell, for example made of stainless steel, a corresponding hardness of the material is necessary, depending on the thickness. At high loads faced with train speeds up to 400km / h hardness of the outer metallic shell provides less flexibility and therefore demands for two or more sectional shells (e.g., half shells).

[0048] In an example, stainless steel EN 1.4301 (AISI 304, DIN X5CrNil8-10, UNS S30400), which is a chrome-nickel steel, may be used for the outer metallic shells. Due to its good processing properties and its high corrosion resistance, this material is advantageous for wheelset protection. The high elasticity (breaking elongation of 45%) in combination with the hardness or tensile strength (500 to 700N / mm2) is important. It differs from other materials (such as EN 1.4307) in that it has a significantly higher carbon content. In general, a stainless steel with breaking elongation greater or equal about 45% may be used.

[0049] Based on the requirements of different bogies and train types, the thickness of the outer metallic sectional shells may range between 1.5mm and 2.5mm for stainless steel, between 3.0mm and 6.0mm for aluminium, and between 3.0mm and 4.5mm for titanium.

[0050] In embodiments, the segment shells may be made of Dyneema® Composite Fabric (DCF), also known as Cuben Fiber (CTF3), which is a ballistic protection high-performance composite fiber material used in high-strength, low-weight applications. Other ballistic protection high performance fiber materials that can be used to make the segment shells can be aramid or fiberglass-reinforced plastic, as initially mentioned.

[0051] DCF can be obtained by dissolving UHMWPE powder and then heating it in an extruder, using e.g. a gel-spinning process to disentangle the molecules. The heated substance is forced through a plate with hundreds of tiny holes - at which point the resulting elongated molecules begin to resemble a fiber. The fibers may then be placed parallel to each other, impregnated with a water-based resin, and allowed to dry. The fully dried layer is sent to a cross-ply machine where the initial roll is cut into sheets. An additional layer of impregnated filaments may then be placed on top and the two layers are laminated together. Different resins can be impregnated between the layers depending on the specific properties required for the end application.

[0052] Conventionally, DCF plates are produced from the above raw material using heated presses. In some cases, very high pressures (e.g., 500bar) are used in order to obtain a very pressure-resistant and high-performance plate.

[0053] According to embodiments, the proposed circular sectional shells may be manufactured in a pressure vessel (e.g., an autoclave, as described later) that may work with a pressure in the range of lObar due to its conditions. The resultant differently manufactured sectional shells of the protection device have different ballistic performance values, but these only become noticeable under very high impact loads. Using a pressure vessel such as the autoclave allows production of half-shells with an angular width of more than 180°, which is not possible in a heated press. Subsequently, the raw (semi-finished) sectional shells are cut to an exact finished angular and longitudinal dimension using e.g. a waterjet system or 3D laser system.

[0054] In embodiments, a DCF roll fabric with a width of e.g. 1600mm may be used in the pressure vessel to produce half-shells as semi-finished products, which are then cut to their exact dimensions. This also enables cost-effective production of different half-shell formats for different train axles.

[0055] In embodiments, semi-finished products are produced in a pressure vessel (e.g., autoclave) to obtain raw half-shells with a width of the DCF web (e.g., 1600mm) and a circular arc (e.g., slightly larger than 180°), which are then used to produce various sectional shells by exact cutting (e.g., cut-to-size long, medium, short). Thereby, several prefabricated sectional shells can be produced from one raw shell. The DCF sectional shells are then combined with a metallic outer shell (made of e.g. stainless steel with a thickness of e.g. 2mm) to provide substantially enhanced protection against impact loads of relatively heavy gravel stones, i.e., prevention of damage to the (paint layer on the) wheel shaft.

[0056] Fig. 1 shows a cross-sectional view of a protection device 1 according to a first embodiment mounted on a wheelset axle 2. The protection device 1 comprises two half-shells 3a, 3b and a housing 4 made of sheet metal. Due to their matched circular shape, the halfshells 3a, 3b can be easily applied to the wheelset axle 2.

[0057] The sheet metal of the housing 4 may consists of stainless steel. The housing consists of two separate housing parts 4a and 4b, which are jointly retained on the wheelset axle 2 by connecting means (e.g., in the form of hose clips) (not shown in Fig. 1). The two- piece configuration of the housing 4 simplifies mounting. The housing parts 4a and 4b may be appropriately pre-shaped, such that a less flexible material can be selected, which increases shock resistance of the housing 4.

[0058] As an additional option, incisions (not shown) may be provided at the free longitudinal or axial ends of the housing parts 4a, 4b. These incisions define tongues, which are easy to bend, such that the housing 4 may be simply adapted to the geometry of the wheelset axle 2, which is generally thicker in its end region, at which the wheels are mounted. The tongues may simply be bent outwards, such that on mounting of the housing 4 the latter may be simply adapted to the geometry of the wheelset axle.

[0059] Similarly, the half-shells 3a, 3b may be widened at their free longitudinal or axial ends 8, as shown in Fig. 5.

[0060] FIG. 2 shows a perspective view of a further exemplary protection device according to a third embodiment. Again, the housing 4 enveloping the half-shells 3a, 3b is composed of two separate housing parts 4a and 4b. At its free peripheral sides each housing part 4a, 4b comprises an overlap deflection 9, such that at these sections the outer diameter of the protection device 1 is slightly expanded. With the overlap deflection 9, the housing part 4a or 4b respectively projects over the undeflected peripheral side of the respective other housing part 4b or 4a. In these regions the housing parts 4a and 4b therefore overlap. This prevents that a space / gap is formed between the mutually facing peripheral sides of the housing parts 4a and 4b. In this way, the half-shells 3a, 3b and thus the wheelset axle 2 can be shielded even better. In an example, the overlap deflection 9 of one housing part may be S-shaped, wherein the non-deflected free peripheral side of the other housing part may extend under the overlap deflection 9.

[0061] To clamp the housing 4 and the half-shells 3a, 3b to the wheelset axle 2, retaining means are used, which may comprise a flexible strap 11 with retaining eyelets at its two free ends, which arise for example by turning over the strap 11 appropriately and stitching the turned-over end to the strap. A clamp clip of a clamping fastener may extend through this retaining eyelet. In the process, the strap 11 surrounds the housing 4 and retains the housing 4 and the half-shells 3a, 3b on the wheelset axle 2.

[0062] Alternatively, the half-shells 3a, 3b and the housing parts 4a, 4b may be retained on the wheelset axle 2 by connecting means in the form of hose clips or the like.

[0063] Figs. 3A to 3C shows perspective views of a height-reducing bandage fixation system with submerged closing elements for use in various embodiments.

[0064] The closing elements of the bandage fixation system comprise a pair of bending elements 32 that protrude in vertical direction and between which the strap 11 of the retaining means can be placed and then fixed (clamped) by bending the bending elements 32 towards the horizontal direction. Additionally, the closing elements comprise a vertically protruding eye portion 34 through which an end of the strap 11 can be inserted and flapped around to be placed between the two bending elements 32 for fixation. The eye portion 34 may comprise a horizontal tooth shaped or other friction-enhanced edged portion facing away from the bending elements 32 to provide increased friction for better fixation when the strap 11 is flapped around the eye portion 34.

[0065] In examples, the closing elements may be stamped out and provided on a separate metal sheet or may be directly stamped out of one of the metallic housing parts 4a or 4b to reduce the radial dimension of the closing elements. In the first case, the respective metallic housing part 4a or 4b may comprise respective openings (matched through holes) through which the closing elements can be inserted from the radially inner surface of the housing part 4a or 4b to protrude from the outer surface of the housing part 4a or 4b.

[0066] Fig. 3A shows a perspective view of the closing elements with a portion of a metal sheet (e.g., a separate base plate or a portion of the housing part 4a or 4b) from which the bending elements 32 and the eye portion 34 are stamped out and bent in a vertical direction so as to protrude therefrom.

[0067] Fig. 3B shows a perspective view of the metallic housing part 4b with the halfshells 3a, 3b and two immersed (e.g., integrated or inserted) bending elements 32 and eye portions 34 of the retaining means after fixation of both ends of a strap 11, wherein end portions of the strap 11 have been flapped around the eye portions 34 and fixed by bending down the bending portions 32.

[0068] Fig. 3C shows a perspective view of the entire metallic housing part 4b with five pairs of integrated bending elements 32 and eye portions 34 (or openings for inserting the bending elements 32 and eye portions 34) to fix both ends of five straps 11 at a respective axial strap distance D in the range of 100 to 200mm (e.g., 150mm).

[0069] The strap distance D may be selected e.g. in dependence on the maximum speed of the rail vehicle (e.g., train) to improve fixation at higher speeds by using more straps 11 with less strap distance D.

[0070] The stap 11 may be a flexible band made of a plastic or metal (e.g., Bandimex® or the like) with an exemplary dimension of 19mm x 0.75mm.

[0071] Due to usual size tolerances of the wheelset axles and their coating, the inner half-shells 3a, 3b of the ballistic protection high performance fiber material may form a circular gap between them after mounting. Therefore, the outer metallic half-shells of the housing parts 4a, 4b of the housing 4 should be mounted on top of the inner halfshells 3a, 3b with a circular offset as shown in Figs. 1 and 2 (preferably 180° as shown in Fig. 2), so that the circular gap between the inner half-shells 3a, 3b is fully covered by the outer half-shells of the housing parts 4a, 4b.

[0072] Fig. 4 schematically shows a side view and a front view of a first example of the half-shells 3a, 3b of the protection device 1 according to various embodiments.

[0073] As can be gathered from Fig. 4, the half-shells can be defined by specific parameters comprising a longitudinal or axial length L, a thickness d, and an inner curvature radius R.

[0074] In an example, the half-shells may be manufactured in different sizes based on the wheelset axles to be protected. These sizes may comprise a short version with R=91.5mm, d=3mm and L=119mm, a medium version with R=91.5mm, d=3mm and L=260mm, and a long version with R=91.5mm, d=3mm and L=908mm, each adapted to practical dimensions of wheelset axles to be protected. High-speed trains, for example, may have 16 axles, i.e. 16 motor axles (driving wheels of the motor) and 16 trailer axles (running wheels of the train) with 2 long half-shells each for the motor axles and 4 medium and short half-shells each for the train axles. Thus, for such a train construction, 32 half-shells of the long version and 64 half-shells of the medium and short versions are required.

[0075] Fig. 5 schematically shows a perspective view of a second example of the half-shells 3a, 3b of the protection device 1 according to various embodiments.

[0076] In the second example, the half-shells are manufactured with widened or expanded end portions 8. Thereby, the half-shells can be better adapted to a geometry of the wheelset axle, when it is thicker in its end region where the wheels are mounted.

[0077] In an example which may be applied to the small shell version, the widened end portions may be configured with an axial length of 20mm, a bending radius of 75mm and a maximum open-end displacement of 2.7mm from the non-widened position.

[0078] Fig. 6 shows a flow diagram of a process of manufacturing a half-shell for a protection device according to various embodiments.

[0079] More specifically, the process is used for producing raw half-shells (i.e., semi-finished products) for the protection device of embodiments described herein.

[0080] In examples, production material for manufacturing the half-shells may include Dyneema® hard ballistic laminate (such as HB24 or HB26) or another ballistic protection high performance fiber laminate. Moreover, consumables such as release liner, tear-off fabric and woven ventilation material may be used in the proposed manufacturing process.

[0081] For optimal conversion of energy introduced by projectiles or fragments, exceptionally high performance is required for ballistic protection systems. Crucial factors are controlled deformation, delamination, or destruction of the half-shells. Beyond that, high adhesion, strength, or elasticity are decisive parameters in the development of the proposed protection device. Choosing the right adhesive system for joining different materials and components is crucial for the overall performance of the ultimate ballistic protection.

[0082] Benefits of thermoplastic adhesive films for ballistic protection include easy processing of the adhesive, defined and consistent adhesive mass distribution, broad spectrum of bondable materials, combination of different adhesive properties with multilayer films allowing surface modification to bond difficult substrates or make is accessible for diverse coating and paining processes.

[0083] Preparatory activities of the proposed manufacturing process include cutting the Dyneema® films to the desired size.

[0084] In step S100, a separation / release film (SF) is applied on a circular winding tube (WT) and fixed e.g. with adhesive tape on the right and left ends.

[0085] Thereafter, in step S102, nine or any suitable different number n of layers of the UHMWPE film (nxDN, e.g., Dyneema® with a size of 370mm x 1650mm) or other ballistic protection high performance fiber film are placed on the separating / release film and fixed e.g. with adhesive tape.

[0086] In subsequent step S104, the entire layer structure (nxDN / SF / WT) is covered with a separation / release film (SF) which is fixed e.g. with adhesive tape.

[0087] Then, in step S106, all previous fixations (e.g., previously placed fixation / adhesive tapes (FT)) are removed, except for the last layer (separation / release film) which remains fixed.

[0088] In the next step S108, a pressure metal plate (PM, e.g., 0.5mm sheet made of e.g. V2A stainless steel) is placed on top of the entire layer structure and fixed e.g. with adhesive tape (e.g., on the circumferential short sides).

[0089] Thereafter, in step S110, the winding tube with the entire layer structure placed thereon is wrapped with peel ply (PP) or other tear-off fabric (which can be reused later).

[0090] Additionally, in step S112, the winding tube with the entire layer structure is folded in an air ventilation fabric (e.g., tradename Airwave® (AW)) made of air textured yarn, where an air jet is used to create tiny loops in the yarn.

[0091] Moreover, in step S114, the winding tube with the entire layer structure is wrapped in vacuum film (VF, e.g., a foil tube) and sealed airtight (using e.g. a foil sealer).

[0092] Then, in step S116, the winding tube with the entire layer structure is positioned on a matched holding structure of a table of an autoclave (pressure vessel) and connected (e.g., suction lines for vacuum generation and / or fixation on the holding structure) for an autoclave lamination / vulcanization process (AC). The air ventilation fabric facilitates the vacuum generation in the autoclave. In an exemplary serial manufacturing process depending on the autoclave and other equipment, 20 to 40 raw half-shells (each with a raw length of 1600mm) could be processed per cycle.

[0093] In step S118 after the autoclave process, the vacuum foil, the air ventilation fabric, the peel ply and the pressure plate are removed, while the laminated raw half-shell still remains on the winding tube. A marker (e.g., felt-tip pen) may now be used to draw a parallel line along the long edge of the half-shell, as a marking for the later cutting process.

[0094] In step S120 after edge marking, the laminated raw half shell is removed from the winding tube.

[0095] Then, in step S122, a cutting process (e.g., laser cutting (LC)) is initiated (e.g., at a separate facility) with a recording of dimensions and set-up / documentation of the cutting program. Cutting programs, which may have been created offline, may then be loaded onto a robot of the cutting device and optimized there. The dimensional accuracy may be adjusted via several measuring loops.

[0096] Depending on the cutting gas, laser intensity, material and requirements (e.g., ox- ide-free edges), different cutting processes may be used, such as flame cutting (e.g. for non-alloy and low-alloy stainless steels) with a laser intensity of less than 107W / cm2 based on an exothermic reaction (ignition / combustion) with the material that indirectly supports the cutting process, or fusion cutting (for higher alloy stainless steels, aluminium, titanium) with a laser intensity of less than 107W / cm2 based on blowing out the material from the kerf by means of high pressure to avoid reactions / oxidations, or sublimation cutting (for non-metals such as wood, paper and plastic) with a laser intensity of more than 107W / cm2 based on a sufficiently high laser intensity to evaporate the material, whereby the cutting gas prevents material reactions / oxidation.

[0097] In the present embodiment, the laminated raw half-shells made of UHMWPE composite or other ballistic protection high performance fiber material may be cut with a carbon dioxide laser using fusion cutting with a power of max. 3.5kW, constant wave (CW) and a wavelength of 10600nm using a plastic cutting head.

[0098] In more detail, half-shells of different sizes (e.g., the three sizes described above or other sized adapted to the size of different wheelsets of different train types) may be cut out from the pre-finished (raw) half-shells. A prefabricated matched holding device can be set up for this purpose, as explained later with reference to Figs. 8A to 8C. The matched holding device can be used for correctly placing the pre-finished half-shells in order to cut several variants of the final half-shell.

[0099] Finally, in step S124, edges (axial ends) of the pre-finished laminated half-shell may be deburred and optionally widened or expanded, as described in connection with Fig. 5 above, by a suitable expansion process using e.g. pressure moulding or the like.

[0100] Note that step S124 may be skipped if the winding tube already has an outer shape with integrated radially expanded portions for shaping the laminated half-shell.

[0101] Thereby, a highly flexible and efficient manufacturing process can be provided, which allows production of a unique size of raw half-shells followed by an individualized cutting process that can be adapted to the wheelset axle, bogie and / or train type.

[0102] Fig. 7 schematically shows a cross-sectional view of an autoclave 76 which can be used in connection with the proposed manufacturing process (e.g., as described above with reference to Fig. 6).

[0103] The autoclave 76 is a pressure vessel used to carry out industrial and scientific processes requiring elevated temperature and pressure in relation to ambient pressure and / or temperature. Autoclaves are used in industrial applications, especially in the manufacturing of composites, especially for melding multiple layers without any voids that would decrease material strength. The high heat and pressure that autoclaves generate help to ensure that the best possible physical properties are repeatable.

[0104] In Fig. 7, a layered object 71 (e.g., the winding tube with the entire layer structure of step 116 of Fig. 6) is placed in a chamber of the autoclave 76 and comprises the plurality of UHMWPE layers (not shown in Fig. 7) to be laminated. It may be mounted on a carrier 75 (an example of which is described below with reference to Figs. 8A to 8C) and may be introduced into the autoclave 76 by means of a movable device 74.

[0105] As explained above, the object 71 is surrounded by a fluid-tight, flexible or expansible envelope 73, in which a reduced pressure (vacuum) is produced (cf. step 114 of Fig. 6). Pressure and heat are applied to the enveloped object 71 to vulcanize (laminate) the UHMWPE layers. The temperature used may be in a range 140°C - 170°C. Reduced pressure is maintained during vulcanization.

[0106] In an example, pressure is applied first, then the temperature is raised, for vulcanization. As explained above with reference to Fig. 6, preparation of the object 71 may take place outside the autoclave 76 in which vulcanization is completed. The reduced pressure used in the object 71 may be about 80hPa, while the positive pressure applied in the autoclave 76 may be in the range 0.1 - 2MPa. The vulcanization temperature may be in a range of 150°C - 160°C.

[0107] Between the UHMWPE layers and the envelope 73, a (diffusion) layer (not shown in Fig. 7) for better propagation of a negative pressure (e.g., the above-mentioned air ventilation fabric made of air textured yarn (cf. step S112), a fleece, a grid or a gas-permeable layer of any kind).

[0108] The heat required for vulcanization may be generated by an internal heating device 78 or by an external hot air system.

[0109] Furthermore, the vacuum acting on the UHMWPE layers within the envelope 73 of the sealed object 71 may be generated via a vacuum line 77 and a vacuum connection of the autoclave 76 by means of a vacuum generating device or a vacuum pump 79.

[0110] Thereafter, a vulcanization pressure is built up within the autoclave 76 by means of any medium via an overpressure supply 72. At the same time, the interior of the autoclave is heated.

[0111] Further details about the processing in the autoclave 76 can be gathered from e.g. EP 1 882 573 Al.

[0112] Figs. 8A to 8C schematically show perspective side views of a matched holding device for accommodating a raw half-shell (semi-finished product) 30 during a cutting process (e.g., step S122 of Fig. 6) without the raw half-shell 30 (Fig. 8A) and with the raw halfshell 30 prior to (Fig. 8B) and after (Fig. 8C) laser cutting.

[0113] In the present example, the holding device is configured with a half-cylindrical upper surface 18 (having an outer radius that at least substantially matches with the inner radius (R in Fig. 4) of the raw half-shell) to accommodate the raw half-shell 30 as obtained from the pressure vessel (autoclave).

[0114] The holding device comprises a plurality of two-armed stands 14 mounted on a common elongated foot bar 17. The two-armed stands 14 that support respective half- cylindrical holding sections (nests) matched to optional cutting sizes of the half-shells and separated by cutting gaps 12 through which the cutting process can be performed.

[0115] In the example of Fig. 8A, the cutting gaps 12 are arranged to cut the raw half-shell 30 either into four smaller half-shells of a length of e.g. 119mm (small variant) or two larger half-shells of a length of e.g. 260mm (medium variant). Fig. 8B shows a state prior to the cutting process, where the raw half-shell 30 is placed on the holding section and the cutting gaps 12 are thus covered by the raw halfshell 30.

[0116] Fig. 8C shows a state after the cutting process, where the raw half-shell has been cut into four sections (i.e., small variants) of cut half-shells 3a / 3b, as defined by the cutting gaps 12.

[0117] In order to attach (e.g., screw) the holding device to a cutting machine, a fixation substructure (not shown) may be provided at the elongated foot bar 17.

[0118] As an additional option, the holding sections of the holding device may be equipped with suction holes and suction ports 16, via which a suction force can be applied to the raw half-shell to secure (press) it on the holding device. Optionally, holes that are not needed can be closed (e.g., by applying adhesive strips or other covering / closing material or elements).

[0119] If the raw half-shell 30 is not completely in contact with the surface of the holding sections 10, the suction ports 16 may not be able to exert a sufficient suction force to fix the raw half-shell 30. The shorter half-shells may then slip during the cutting process. This can be prevented e.g. by adding recessed silicone suction bellows and / or automatic tensioners.

[0120] Moreover, to avoid twisting and / or displacement, stops and / or markings (e.g., align a central longitudinal line on the raw half-shell 30 with a marking on the holding device) and / or holes / pins may be provided in the waste material that is cut-off from the raw half-shell. For long parts such as the raw half-shell 30, a stop edge may be formed to provide a length reference for proper sizing of the cut half-shells 3a / 3b.

[0121] Depending on the type of laser, a high-energy beam generated in a laser beam source may be guided to a robot base via a glass fiber or freely propagated via mirrors. If the beam is guided in a fiber, the beam may be collimated (parallelized) with the help of a lens after it has been decoupled from a fiber connector. Then, regardless of the type of laser, the beam propagates freely via a mirror system within a robot arm, which may be completely encapsulated and flushed, all the way to a cutting head where the beam is focused via another lens to a small point. At this point, the laser beam on the surface of the material is partially absorbed and heats the material above the melting point or evaporation temperature. When the beam has fully penetrated the material, the cutting head is moved forward with constant melting or evaporation of the material. The non-evapo- rated material may be blown out of the resulting gap with the help of a cutting gas.

[0122] After the laser has cut through the UHMWPE composite or other ballistic protection high performance fiber material of the raw half-shell 30, it may partially melt the material on the opposite side of the raw half-shell 30. This may result in an exposure of the inner fiber material of the raw half-shell 30, so that it may no longer be protected by the outer matrix of the raw half-shell 30. This effect can be eliminated or at least mitigated by slightly tilting the laser beam along the longitudinal edges. Alternatively, the device could be supplemented with guard / protection elements.

[0123] In an example, for a linear cut without deviations, edges may be cut with a speed of 30mm / s. Longer longitudinal edges of the long half-shell variant may be cut with a faster speed of lOOmm / s.

[0124] To summarize, a process for manufacturing a protection device for protecting a wheelset axle of a rail vehicle has been described, wherein semi-finished products made of vulcanized layers of ballistic protection high performance fiber (e.g., ultra-high-molec- ular-weight polyethylene (UHMWPE) such as Dyneema®, or aramid or fiberglass-rein- forced plastic) are processed in an autoclave as raw half-shells with a width of a UHMWPE web (e.g., 1600mm) and with a semicircular arc (e.g., > 180°). The raw half-shells are then subjected to a cutting process to produce various prefabricated half-shells of different sizes (e.g., long, medium and short) from one raw shell, which is not possible in a conventional pressing process. The obtained protection device comprises sectional shells (e.g., half-shells) made of vulcanized layers of the ballistic protection high performance fiber in combination with a metallic outer shell for protection against impact loads of relatively heavy gravel stones, e.g., prevention of damage to a wheel shaft.

[0125] While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive. The invention is not limited to the disclosed embodiments. Any number and size of sectional shells (e.g., quarter-shells etc.) may be placed around an object to be protected. The sectional shells can be of any curved or bent shape (e.g., circular, elliptical, polygonal, etc.) that is matched to the surface of an object to be protected by the shells. Moreover, the sectional shells may made of any type of ballistic protection high performance fiber material. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. A single processor or other unit may fulfil the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. The foregoing description details certain embodiments of the invention. It will be appreciated, however, that no matter how detailed the foregoing appears in the text, the invention may be practiced in many ways, and is therefore not limited to the embodiments disclosed. It should be noted that the use of particular terminology when describing certain features or aspects of the invention should not be taken to imply that the terminology is being re-defined herein to be restricted to include any specific characteristics of the features or aspects of the invention with which that terminology is associated.

Claims

CLAIMS1. A method of manufacturing a device (1) for protecting a wheelset axle (2) of a rail vehicle, the method comprising: placing a layered structure including a plurality of layers of ballistic protection high performance fiber, in particular ultra-high-molecular-weight polyethylene, UHMWPE, or aramid or fiberglass-reinforced plastic, on a winding tube with a size adapted to the outer shape of the wheelset axle (2); processing the plurality of UHMWPE layers on the winding tube in a pressure vessel (76), in particular an autoclave, to obtain a laminated raw sectional shell (30) of the device (1); and cutting the raw sectional shell (30) into a predetermined length that is adapted to the length of the wheelset axle (2).

2. The method according to claim 1, further comprising placing (S110) a pressure metal plate on top of the layered structure.

3. The method according to claim 2, further comprising placing (S112) an air ventilation fabric on top of the pressure metal plate.

4. The method according to any one of the preceding claims, further comprising wrapping (S114) the winding tube with the layered structure in a vacuum film that is sealed airtight.

5. The method according to any one of the preceding claims, further comprising placing the laminated raw sectional shell (30) on a matched holding device with a plurality of cutting gaps (12) adapted to predetermined lengths of the wheelset axle (2).

6. The method according to claim 5, further comprising applying a suction force to a holding section (10) of the holding device to fix the laminated raw sectional shell (30) on a matched holding device.

7. The method according to any one of the preceding claims, further comprising widening longitudinal ends (8) of a cut sectional shell (3a, 3b) in a press mould or by providing a corresponding surface shape on the winding tube.

8. A device (1) for protecting a wheelset axle (2) of a rail vehicle, the device(I) comprising two or more sectional shells (3a, 3b) made of vulcanized layers of ballistic protection high performance fiber, in particular ultra-high-molecular-weight polyethylene, UHMWPE, or aramid or fiberglass-reinforced plastic, to be placed around the wheelset axle (2), and a metallic housing (4) arranged to enclose the sectional shells (3a, 3b).

9. The device (1) according to claim 8, further comprising retaining means(II) configured to retain the sectional shells (3a, 3b) and the metallic housing (4a) when mounted on the wheelset axle (2).

10. The device (1) according to claim 8 or 9, wherein the device (1) comprises two half-shells (3a, 3b) and two portions (4a, 4b) of the metallic housing to be placed around the wheelset axle (2).

11. The device (1) according to any one of claims 8 to 10, wherein the retaining means comprise a bandage fixation system with closing elements (32, 34) submerged in the metallic housing (4).

12. The device (1) according to any one of claims 8 to 11, wherein the sectional shells (3a, 3b) to be placed around the wheelset axle (2) are made of Dyneema® HB24 or HB26 layers.

13. The device (10) according to any one of claims 8 to 12, wherein the sectional shells (3a, 3b) each have a radial thickness of 3mm and the metallic housing (4) has a radial thickness of 2mm.

14. The device (10) according to any one of claims 8 to 13, wherein the metallic housing (4) is made of stainless steel with a breaking elongation greater or equal 45%, such as EN 1.4301.

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