AU2017203802B2

AU2017203802B2 - Railway vehicle body structure and method of assembly of such a body structure

Info

Publication number: AU2017203802B2
Application number: AU2017203802A
Authority: AU
Inventors: Olivier Gries; Stephane Roll
Original assignee: Alstom Holdings SA
Current assignee: Alstom Holdings SA
Priority date: 2016-06-09
Filing date: 2017-06-06
Publication date: 2022-11-03
Anticipated expiration: 2037-06-06
Also published as: EP3254923A1; AU2017203802A1; EP3254923B1; ES2721792T3; PL3254923T3; DK3254923T3; FR3052422B1; FR3052422A1

Abstract

The invention relates to a railway vehicle body structure, comprising a chassis, at least one panel, and a plurality of bolts fastening the panel on the chassis, each bolt including a shank and keeping a surface of the panel across from a surface of the chassis along an axis of the shank. The body structure further comprises friction sheets. For each of the bolts, at least one of the friction sheets is compressed by the bolt between the surface of the panel and the surface of the chassis. The surface of the panel has a sliding strength relative to the surface of the chassis along a longitudinal direction perpendicular to the axis, said friction sheet being suitable, with constant tightening of the bolt, for increasing the sliding strength. Figure 2 2/4 -- 0B 264 10B I S 26A FIG.

Description

2/4

-- 0B

26A 264 10B

IS FIG.

Railway vehicle body structure and method of assembly of such a body structure

The present invention relates to a railway vehicle body structure, the body structure comprising a chassis, at least one panel, and a plurality of bolts fastening the panel on the chassis, each bolt of the plurality including a shank and keeping a surface of the panel across from the surface of the chassis along an axis of the shank. The present invention also relates to a method for assembling such a body structure. To produce a body structure of a railway vehicle, such as a car, or a carriage, it is known to assemble panels, for example side panels, on a chassis, for example forming the framework for the future floor and on a pavilion forming the future roof of the vehicle. Such panels are generally fastened by welding, riveting or bolting. In the case of bolting, to obtain correct fastening of the panel, the bolts generally have diameter M20. However, due to the length of the chassis (typically 23 meters in modern convoys), and the number of bolts per meter to obtain a correct assembly, the total mass of the bolts is high, around 350 kg. It is not, however, possible to go from M20 bolts to M16 bolts, since the number of bolts would then have to be increased, which would not significantly reduce the total mass. Furthermore, by increasing the pre-stress by choosing stronger bolts with diameter M16, one would increase the cost of the fastening elements, and make the implementation of the tightening more complex. Riveting is interesting, especially in accessible zones on a single side (called blind riveting), but the diameters of structural rivets do not exceed 12 mm, and the rivets have a low shear strength. Bolts are then used with blind crimping having a diameter of 12 to 16 mm mounted adjusted, since the pre-stress of these elements is too low to have them work without sliding, as is the case for a non-blind bolts. Adjusted mounting presents production difficulties related to compliance with the necessary allowances: precision of the machines, counter-drilling. This last operation has the drawback of producing shavings that are incompatible with the assembly of pre-trimmed or painted panels. This results in excess costs related to protection of the panels to obtain an acceptable quality. In order to improve the sliding resistance of the bolted or riveted assemblies, it is also known to perform surface treatments (paint, sanding), which is costly to implement. Welding is interesting to lighten the structure and makes it possible to obtain continuous bonds distributing the stresses, and which are therefore very strong. However, it does not allow the same flexibility as bolting or riveting. For example, the assembly of box structures from several materials is more difficult to do by welding. Furthermore, welding requires special qualifications that are costly in terms of training for staff.

In this context, there is a need to resolve all or some of the aforementioned problems, i.e., in particular to provide a body structure in which the panel is correctly fastened on the chassis, with a total mass gain, the fastening remaining easy to do and comparable to or lower than the existing costs. To that end, the present invention relates to a body structure of the type described above, wherein: - the body structure further comprises friction sheets, - for each of the bolts of said plurality, at least one of the friction sheets is compressed by the bolt between the surface of the panel and the surface of the chassis, and - the surface of the panel having a sliding strength relative to the surface of the chassis along a longitudinal direction perpendicular to the axis, said friction sheet is suitable, with constant tightening of the bolt, for increasing the sliding strength. According to specific embodiments, the body structure comprises one or more of the following features, considered according to all technically possible combinations: - each friction sheet is respectively positioned around one of the bolts of said plurality; - for each of the bolts of said plurality, the friction sheet has a general washer shape substantially centered on the axis of the shank; - for each of the bolts of said plurality: - the shank has a shank diameter, and - the washer has an inner diameter smaller than or equal to the shank diameter increased by 3 mm, preferably increased by 1.5 mm; - each of the bolts of said plurality comprises a nut, and: - the nut has an outer nut diameter, - the chassis locally has a chassis thickness along the axis of the shank, between the nut and the washer, and - the washer has an outer diameter smaller than or equal to the sum of the outer nut diameter and twice the thickness; - for each of the bolts of said plurality: - the shank includes a head having a bearing diameter, - the panel locally has a thickness along the axis of the shank, between the head and the washer, and - the washer has an outer diameter smaller than or equal to the sum of the bearing diameter of and twice the thickness; - for each of the bolts of said plurality:

- the chassis includes, at least locally, a transverse slot intended to allow transverse positioning of the panel relative to the chassis, the chassis having two lips situated on either side of the slot, each of the lips defining a part of said surface of the chassis, and - the friction sheet includes a first part and a second part respectively sandwiched between the two lips and the panel surface; - for each of the bolts of said plurality: - the friction sheet includes at least one portion glued on the panel surface, and - the glued portion extends only between the two lips along a direction perpendicular to the transverse direction, such that the glued portion is situated outside the first part and the second part of the friction sheet; - for each of the bolts of said plurality, the friction sheet includes at least one reference able and intended to allow an angular orientation of the friction sheet relative to the panel around the axis of the shank, the angular orientation being intended to guarantee that the glued portion situated on the friction sheet across from the panel surface is oriented angularly around the axis of the shank so as to extend only between said two lips; and - the friction sheet includes at least two references able and intended to allow said angular orientation of the friction sheet, the two references being diametrically opposite relative to the axis of the shank, the two references respectively comprising at least one notch situated in a radially outer edge of the friction sheet. The present invention also relates to a method for assembling a railway vehicle body structure, the method comprising at least the following steps: - fastening at least one panel on a chassis using a plurality of bolts, each bolt of the plurality including a shank and keeping a surface of the panel across from the surface of the chassis along an axis of the shank, - providing friction sheets, and - for each of the bolts of said plurality, compressing at least one of the friction sheets between the surface of the panel and the surface of the chassis compressed by the bolt, the surface of the panel having a sliding strength relative to the surface of the chassis along a longitudinal direction perpendicular to the axis, the shear sliding strength being increased by the friction sheet with constant tightening of the bolt. The invention will be better understood upon reading the following description, provided solely as an example, and in reference to the appended drawings, in which:

- figure 1 is a general schematic illustration of a body structure according to the invention, - figure 2 is a sectional view along a vertical plane of a detail of the body structure shown in figure 1, - figure 3 is an exploded view of the chassis and the panel shown in figures 1 and 2, - figure 4 is a front view of one of the friction sheets shown in figures 2 and 3, and - figure 5 is a detail of figure 2 showing the dimensions of one of the bolts and one of the friction sheets illustrated in figure 2. In reference to figure 1, a body structure 1 is described according to the present invention that is intended to be part of a railway vehicle, not shown. The body structure 1 comprises a body bottom 2 and an upper pavilion 3, respectively including chasses 5, 6. The body structure 1 also comprises two panels 10 forming two side walls 12A, 12B. The assembly of the panels 10 on the body bottom 2 and the upper pavilion 3 forms a "tube" intended to be closed at both ends by transverse end walls (not shown). The mounting of one of the panels 10 on the chassis 5 situated in the body bottom 2 is described in reference to figures 2 and 3. The mounting of the panels 10 on the chassis 6 situated in the roof is similar and will not be described. The body structure 1 comprises a plurality of bolts 15A, 15B for fastening the panel 10 on the chassis 5, and a plurality of friction sheets 20A, 20B respectively compressed by the bolts 15A, 15B between the chassis and the panel. The body structure 1 for example comprises other panels (not shown) similar to the panel 10, the panels advantageously being fastened on the chassis 5 successively along a longitudinal direction L of the chassis. The longitudinal direction L is for example the forward travel direction of the future railway vehicle and horizontal when the body structure 1 is oriented as it is intended to be in this vehicle. The chassis 5 is for example a metal chassis made from aluminum, made from extruded profiles known in themselves. The chassis 6 for example has a structure similar to that of the chassis 5. According to one alternative that is not shown, this chassis is made from mechanically welded steel. Only part of the chassis 5 is shown in figures 2 and 3. The illustrated part for example corresponds to a longitudinal portion of a lateral edge of the future floor of the vehicle.

On the side of the panel 10, the chassis 5 includes a face 22 (figure 3) for example defining two slots 24A, 24B oriented longitudinally and superimposed along a direction Z perpendicular to the longitudinal direction and an axis D of the bolt 15A. The direction V is for example substantially vertical. The slots 24A, 24B are suitable for respectively receiving nuts 26A, 26B of the bolts 15A, 15B while blocking their rotation around the axis D (figures 2 and 5). The slots 24A, 24B being similar to one another, only the slot 24A will be described in detail below. The slot 24A is advantageously cruciform in section perpendicular to the longitudinal direction L (i.e., in the plane of figures 2 and 5) so as to marry the shape of the bolt 15A. The slot 24A defines two longitudinal lips 28 positioned across from one another along the direction V. The slot 24A is suitable for allowing the nut 26A to slide in longitudinal translation as long as the bolt 15A is not tightened. The lips 28 partially close the slot 24A and prevent the nut 26A from leaving the slot 24A along the axis D. The lips 28 define a surface 30 (figure 5), which is advantageously planar, and is intended to be in contact with the friction sheet 20A. In the illustrated example, due to the presence of the slot 24A, the surface 30 of the chassis 5 is made from two parts respectively corresponding to the lower and upper lips 28. Still in the illustrated example, the surface 30 corresponding to the lower lip 28 of the slot 24B is separated by a slot 32 from the surface 30 corresponding to the upper lip 28 defined by the slot 24A. The slot 32 for example has a frustoconical section and facilitates positioning along the axis Z of the panel 10 before tightening. The lips 28 for example have a thickness El (figure 5) along the axis D. The thickness El is also the distance separating the nut 26A from the friction sheet 20A when the bolt 15A is tightened. The thickness El is for example comprised between 5 mm and 15 mm, and is advantageously equal to about 10 mm. The panel 10 also advantageously has a cellular structure including a primary wall 34 defining, at each bolt 15A, 15B, a surface 36 intended to be in contact with the friction sheet 20A, 20B, respectively, a skin 38 situated opposite the chassis 5 relative to the primary wall 34, and reinforcing elements 40 extending between the skin and the primary wall. The panel 10 advantageously extends from the illustrated portion of the chassis 5 to the chassis 6.

In the example, the skin 38 defines an opening 42, for example oblong, providing access to two piercings 44A, 44B arranged in the primary wall 34 for the bolts 15A, 15B. The bolts 15A, 15B are for example of type M16. Aside from the nuts 26A, 26B, the bolts 15A, 15B further respectively comprise shanks 46A, 46B oriented parallel to the axis D, and washers 48A, 48B on the side opposite the nuts. In the illustrated example, the shanks 46A, 46B are screws respectively having heads 50A, 50B. According to one alternative that is not shown, the shanks 46A, 46B are studs. The heads 50A, 50B are then for example nuts. A single plate 52 is further inserted between the washers 48A, 48B and the primary wall 34 of the panel 10. The bolts 15A, 15B being similar to one another, only the bolt 15A will be described in detail below. The nut 26A has an outer diameter DEE around the axis D. Still in reference to the axis D, the head 50A of the shank 46A has a bearing diameter DA and is separated from the friction sheet 20A by a distance E2 along the axis D. The bearing diameter DA is for example comprised between 20 mm and 30 mm, and is advantageously equal to about 25 mm. The distance E2 is the sum of the thicknesses of the primary wall 34, the plate 52 and the washers 48A along the axis D. The distance E2 is for example comprised between 10 mm and 20 mm, and is advantageously about 12 mm. The outer diameter DEE is for example comprised between 40 mm and 50 mm, and is advantageously equal to about 45 mm. The shank 46A has a shank diameter DT. The shank diameter DT is advantageously about 16 mm. In the illustrated example, each friction sheet 20A, 20B is assigned to one of the bolts 15A, 15B, in that it is compressed by this bolt and not by another bolt of the plurality. According to alternatives that are not shown, a same friction sheet is compressed by at least two bolts of the plurality. According to another alternative that is not shown, several separate friction sheets are positioned near a same bolt of the plurality, so as to be compressed by this bolt only. The friction sheets 20A, 20B being similar to one another, only the friction sheet 20A will be described in detail below. As shown in figure 4, the friction sheet 20A is generally washer-shaped, centered on the axis D of the bolt 15A.

The friction sheet 20A has a small thickness, advantageously smaller than 0.5 mm, for example equal to about 0.16 mm. It is for example made up of a metal sheet, two layers of nickel-phosphorus fastened on the faces of the metal sheet, and ceramic or diamond particles situated in and on said layers. Said layers and the particles create a roughness typically comprised between 10 pm and 50 pm. The friction sheet 20A is advantageously glued on the surface 36 of the panel 10 to facilitate the assembly of the body structure 1. The friction sheet 20A has an inner diameter DI advantageously smaller than or equal to the shank diameter DT plus 3 mm, preferably less than or equal to DT plus 1.5 mm. The inner diameter DI is according to the ISO standards in force for bores for the passage of fastening screws. The friction sheet 20A has an outer diameter DE advantageously smaller than or equal to a value DMAX1 equal to the sum of the outer nut diameter DE and twice the thickness El. The outer diameter DE is also advantageously smaller than or equal to a value DMAX2 equal to the sum of the bearing diameter DA and twice the thickness E2. As shown in figure 4, the friction sheet 20A comprises two references 54, advantageously diametrically opposite relative to the axis D, making it possible to orient the friction sheet angularly around the axis D relative to the panel 10. The references 54 are further suitable for indicating, to an operator, two gluing zones 56 in which he can place one or several glue spots 58. The references 54 for example have a notch shape made on a radially outer edge 57 of the friction sheet 20A. The zones 56 are defined as the points of an inner face 60 of the friction sheet 20A situated at a distance X from a line L1 parallel to the longitudinal direction L and passing through the axis D, the distance X being smaller than half of the shank diameter DT. Thus, by positioning the glue in the gluing zones 56, then orienting the references 54 along the longitudinal direction L when the friction sheet 20A is glued on the face 36 of the panel 10, the operators ensure that the glued zones will not be sandwiched between the chassis 5 and the panel 10, which prevents subsequent creep phenomena that are bothersome for mastering the pre-stress in the assembly. The friction sheet 20A comprises a first part 62 situated above the zones 56 in figure 4, and a second part 64 situated below. The first part 62 and the second part 64 are free of glue and are sandwiched between the lips 28 and the panel 10.

The assembly of the body structure 1 will now be described. The assembly includes a step for fastening the panel 10 on the chassis 5 using bolts 15A, 15B. The friction sheets 20A, 20B are glued beforehand on the face 36 of the primary wall 34 of the panel 10. The friction sheets 20A, 20B are advantageously glued in the gluing zones 56 identified using the references 54. The friction sheets 20A, 20B are then respectively positioned around piercings 44A, 44B, the references 54 being longitudinally aligned, such that the glued zones 58 are situated between the lips 28 along the direction V. Next, the shanks 46A, 46B of the bolts are inserted into the piercings 44A, 44B. The shanks 46A and 46B are screwed into the nuts 26A, 26B inserted beforehand into the slots 24A, 24B. The slots 24A, 24B block the rotation of the nuts 26A, 26B around the shanks 46A, 46B. The heads 50A, 50B are next screwed using a tool (not shown) through the window 42 until the desired tightening is obtained. This tightening is done to a minimum pre-stress level making it possible to obtain a sufficient pressure at the interface that anchors the friction sheets 20A, 20B on the parts in contact. The friction sheets 20A, 20B are then compressed between the surfaces 30 of the chassis 5 and the surface 36 of the panel 10. Each friction sheet 20A, 20B contributes locally, respectively at the bolts 15A, 15B, to increasing, by friction, the sliding strength or shear strength in the plane defined by the directions L and V. It is thus possible to reduce the diameter, the quality class or the number of bolts 15A, 15B used. For example, by going from M20 to M16 bolts, it becomes possible to lighten the body structure 1 by about 70 kg. Furthermore, the M16 bolts are less expensive than the M20 bolts, such that the cost of the body structure is also reduced. Owing to the features described above, the panel 10 is correctly fastened on the chassis 5, with a mass gain of about 20% of the total mass of the bolts. The fastening is easy to do and less expensive, since M16 bolts are less expensive than M20 bolts and the assembly does not require surface preparation. Furthermore, the dimensional criteria listed above make it possible to optimize the positioning of each of the friction sheets 20A, 20B relative to the panel 10 or the chassis 5. The criteria pertaining to the inner diameter DI make it possible to center the washer on the bolts. The criteria pertaining to the outer diameter DE make it possible to give the washer a maximum diameter lower than both the values DMAX1 and DMAX2 beyond which the material of the friction sheets 20A, 20B no longer significantly contributes to increasing the sliding strength. Lastly, the references 54 make it possible to orient the friction sheets 20A, 20B at the moment when they are placed around the piercings 44A, 44B. The fact that each friction sheet is glued makes it possible to prevent them from moving or being lost during the assembly of the body structure 1. Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps. The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as, an acknowledgement or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates. While various features of embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not by way of limitation. It will be apparent to a person skilled in the relevant art that various changes in form and detail can be made therein without departing from the spirit and scope of the invention. Thus, the present invention should not be limited by any of the above described exemplary embodiments.

Claims

1. A railway vehicle body structure, the body structure comprising a chassis, at least one panel, and a plurality of bolts fastening the panel on the chassis, each bolt of the plurality including a shank and keeping a surface of the panel facing a surface of the chassis along an axis of the shank, wherein: - the body structure further comprises friction sheets, - for each of the bolts of said plurality, at least one of the friction sheets is compressed by the bolt between the surface of the panel and the surface of the chassis, and - the surface of the panel having a sliding resistance relative to the surface of the chassis along a longitudinal direction perpendicular to the axis, said friction sheet is suitable, with constant tightening of the bolt, for increasing the sliding resistance, wherein, for each of the bolts of said plurality: - the chassis includes, at least locally, a transverse slot intended to allow transverse positioning of the panel relative to the chassis, the chassis having two lips situated on either side of the slot, each of the lips defining a part of said surface of the chassis, and - the friction sheet includes a first part and a second part respectively sandwiched between the two lips and the surface of the panel.

2. The body structure according to claim 1, wherein each friction sheet is respectively positioned around one of the bolts of said plurality.

3. The body structure according to claim 1 or 2, wherein, for each of the bolts of said plurality, the friction sheet has a general washer shape substantially centered on the axis of the shank.

4. The body structure according to claim 3, wherein, for each of the bolts of said plurality: - the shank has a shank diameter, and - the washer has an inner diameter smaller than or equal to the shank diameter increased by 3 mm, preferably increased by 1.5 mm.

5. The body structure according to claim 3 or 4, wherein each of the bolts of said plurality comprises a nut, and wherein: - the nut has an outer nut diameter, - the chassis locally has a chassis thickness along the axis of the shank, between the nut and the washer, and

- the washer has an outer diameter smaller than or equal to the sum of the outer nut diameter and twice the thickness.

6. The body structure according to any one of claims 3 to 5, wherein, for each of the bolts of said plurality: - the shank includes a head having a bearing diameter, - the panel locally has a thickness along the axis of the shank, between the head and the washer, and - the washer has an outer diameter smaller than or equal to the sum of the bearing diameter and twice the thickness.

7. The body structure according to any one of claims 1 to 6, wherein, for each of the bolts of said plurality: - the friction sheet includes at least one portion glued on the panel surface, and - the glued portion extends only between the two lips along a direction perpendicular to the transverse direction, such that the glued portion is situated outside the first part and the second part of the friction sheet.

8. The body structure according to claim 7, wherein, for each of the bolts of said plurality, the friction sheet includes at least one reference able and intended to allow an angular orientation of the friction sheet relative to the panel around the axis of the shank, the angular orientation being intended to guarantee that the glued portion situated on the friction sheet across from the panel surface is oriented angularly around the axis of the shank so as to extend only between said two lips.

9. The railway vehicle body structure according to claim 8, wherein the friction sheet includes at least two references able and intended to allow said angular orientation of the friction sheet, the two references being diametrically opposite relative to the axis of the shank, the two references respectively preferably comprising at least one notch situated in a radially outer edge of the friction sheet.

10. A method for assembling a railway vehicle body structure, the method comprising at least the following steps: - fastening at least one panel on a chassis using a plurality of bolts, each bolt of the plurality including a shank and keeping a surface of the panel facing a surface of the chassis along an axis of the shank, the chassis including, at least locally, a transverse slot intended to allow transverse positioning of the panel relative to the chassis, the chassis having two lips situated on either side of the slot, each of the lips defining a part of said surface of the chassis, - providing friction sheets, and

- for each of the bolts of said plurality, compressing at least one of the friction sheets between the surface of the panel and the surface of the chassis compressed by the bolt, the surface of the panel having a sliding resistance relative to the surface of the chassis along a longitudinal direction perpendicular to the axis, the shear sliding resistance being increased by the friction sheet with constant tightening of the bolt, the friction sheet including a first part and a second part respectively sandwiched between the two lips and the surface of the panel.