Note: Descriptions are shown in the official language in which they were submitted.
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A structural element arranged to form at least a part of a
shell of a car body of a railway vehicle
TECHNICAL FIELD OF THE INVENTION AND PRIOR ART
The present invention relates to a structural element arranged to
form at least a part of a shell of a car body of a railway vehicle,
wherein the structural element comprises an external layer
comprising a metal material, an intermediate layer arranged to
form a thermal insulating layer and an internal layer.
In conventional manufacturing of a side wall of a car body of a
railway vehicle, an external metal sheet which is provided on
internal beams in order to increase the stiffness of the metal
sheet is used. In order to prevent buckles to occur in the sheet,
supporting elements are provided which are connected to the
sheet by means of welding. Furthermore, a ventilation layer is
provided in connection with the sheet and a thermal insulating
layer and finally an internal panel. Such a side wall for a car
body is expensive and complicated to manufacture and it has a
large thickness, which encroaches on the internal volume of the
car body. Furthermore, irregularities easily occur in the sheet as
a consequence of internal treatment by, for example, welding
during the mounting of said supporting elements to the sheet.
From DE 38 38 686, EP 544 473 and DE 195 33 532 structural
elements are known, which are intended to be used for forming
shells of a car body of a railway vehicle. The structural elements
in these documents comprise, in addition to the initially
mentioned three layers, also reinforcement elements in form of
through beams or surrounding beams. Such reinforcement
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elements have the effect that the structural elements obtain a
relatively complicated construction, which increases their
manufacturing cost. Such reinforcement beams also increase
the weight of the structural elements, which makes its handling
more difficult.
DE 296 08 643 U 1 shows a structural element which comprises
a portion of a side wall, a roof and a floor of a railway vehicle.
The structural element comprises external and internal layers
formed by a fibre reinforced plastic material. Said external and
internal layers are connected to each other along the edges of
the structural element, wherein they enclose an intermediate
layer. This structural element comprises longitudinal
reinforcement beams at the roof and floor portion of the
structural element. Such reinforcement beams lead also in this
case to a relatively complicated construction of the structural
element. Furthermore, it may be difficult to obtain a completely
even and smooth external surface in a fibre reinforced plastic
material.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a structural
element of the initially mentioned kind, which is inexpensive to
manufacture and which has external and internal surfaces of
high quality at the same time as it enables a rapid and
uncomplicated mounting in the vehicle.
This object in achieved by the initially mentioned structural
element, which is characterised in that the intermediate layer is
fixedly connected to the external layer and the internal layer so
that a structural element in one piece is formed, wherein the
structural element is arranged to constitute a supporting element
of said vehicle body. By such a design, the structural element
does not require through beams or surrounding reinforcement
beams, wherein the manufacturing of the structural element is
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considerably simplified. Such a structural element may also be
manufactured to a low cost at the same time as it may be made
essentially lighter with respect to weight than by prior art
technique. Very advantageous is the fact that, the structural
element comprises an intermediate layer of a thermal insulating
material. Thereby is obtained that no further thermal insulation
need to be provided internally in the vehicle. A wall construction
may thereby be manufactured essentially thinner than by a
conventional construction and encroaches thereby less on the
internal volume of the vehicle.
According to a preferred embodiment of the invention, also the
internal layer comprises a metal material. Such a metal material
may be steel or aluminium. Preferably, both the external and
internal layer comprise sheets of metal which in co-operation
with the intermediate layer forms a structural element with such
a stiffness that it may constitute a supporting component of a
vehicle body. Alternatively only the external layer may comprise
a metal material. Thereby, the external layer will be
dimensioned so that it will carry the main load of the structural
element but it will at the same time be propped and guyed by
the remaining layers so that the structural element without
problem may be used as a supporting component.
According to preferred embodiment of the invention, said
intermediate layer is essentially thicker than said internal and
external layers. In order to provide stability to the external and
internal layers, the intermediate layer comprises such a stiff
material that it supplies stiffness to said structural element.
Such a stiff intermediate layer prevents also in an effective way
that buckles and deformations occur in the relatively thin
external and internal layers. Consequently, such an intermediate
layer has two functions, namely to stiffen the external and
internal layers as well as to provide thermal insulation.
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According to preferred embodiment of the invention, said
intermediate layer is fixedly connected to the internal and
external layers by means of a binder means arranged to work so
that said layers are connected along essentially its entire
surface. ,By connecting said layers to each other along
essentially the entire surface, it is prevented that a local
displacement between the layers occurs under load. Thereby,
the structural element will constitute a very stable, stiff unit
which distributes applied loads essentially along its whole
construction. Said binder means may consist of an adhesive
having good adhesive properties. Hereby, the external and
internal layers will obtain a very even and fine surface, which
has good strength against buckles and deformations.
According to preferred embodiment of the invention, the external
and internal layers of said structural element comprise at least a
curved portion. Usually, it is desired that a shell of a vehicle is
manufactured with curved portions in order to, for example,
decrease the air resistance of the vehicle and to use available
loading profile to obtain an aesthetically attractive visual
sensation. A structural element according to the present
invention, which does not comprise stiffening beams, may in a
rather uncomplicated way be manufactured with curved surface
portions but may also be performed with a plane surface. Said
relatively thin external and internal layers may without problem
each be bent to a desired shape individually or during the
joining process with the intermediate layer. The intermediate
layer may with a suitable choice of material also without problem
be manufactured in a desired shape, wherein such a material
may be a plastic material. Thereafter, said layers are connected
with a suitable adhesive in order to form a structural element,
which has desired curved surfaces.
According to a preferred embodiment of the invention, the
structural element comprises fastening devices for equipment in
the vehicle. Since the internal layer of the structural element has
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a flat surface, which also may carry loads, the possibility arises
to fasten in the vehicle provided internal equipment in the
structural element. For example, fasting channels for seats may
be provided in the structural element, such channels may be
5 fastened in the internal layer or provided so that they also
extend into the intermediate layer. Further material savings are
thereby obtained since there is no need for supporting elements,
for such equipment.
According to another preferred embodiment of the invention,
said structural element forms at least a portion of a side wall or
a portion of a roof of a car body of a railway vehicle. The
present structural element is very favourable to use in railway
vehicles such as in underground railway cars and in railway cars
for transportation of people. It is in the first place the side walls
of the car body, 'which are suitable to be comprised by said
structural element. By making the walls thinner a greater
internal volume for the accommodation of passengers may be
obtained. The vehicle car will also be essentially lighter, which
fact, i.a., influences the energy consumption in a favourable
way. It also favorable to use the present structural element in
the roof of the car body, which by this measure obtains a light
and uncomplicated construction. To use the structural element
in a floor construction of a railway vehicle is also an alternative,
which may not be excluded.
BRIEF DESCRIPTION OF THE DRAWINGS
In the following, preferred embodiments of the invention are
described as examples with reference to the attached drawings,
in which:
Fig 1 shows a plane view of a car body of a railway vehicle
comprising a structural element according to the
present invention,
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Fig 2 shows schematically a cross sectional view of a
structural element according to the present invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF
THE INVENTION
Fig 1 shows a car body 1 of a railway vehicle, comprising a
structural element 2 according to the present invention. The
structural element 2 forms at least a part of a side wall of the
car body 1 and has openings for windows 3. The structural
element 2 may, for example, extend between two door openings
4, of which one door opening 4 is shown in Fig 1. The structural
element 2 comprises an external layer 5 of a first piece of
material comprising a metal material, an intermediate layer 6 of
another second piece of material comprising a thermal insulating
material, and an internal layer 7 of a third piece of material. The
intermediate layer 6 is arranged to be joined together with the
external 5 and the internal 7 layers by means of an adhesive so
that the three pieces of material form a structural element 2 in
one piece. This structural element 2 is intended to be mounted
on the vehicle by means of fastening means, which may be
applied to suitable portions of the structural element 2. The
fastening means, which may, for example, be rivet joint
connections or joint bolt connections, may thereby connect the
structural element 2 at the top to the roof of the railway vehicle
and at the bottom to a lower frame 9. Possibly, also fastening
means may be applied for connecting the structural element 2 to
adjacent side walls.
Before the mounting of the structural element 2 in the vehicle,
fastening devices for internal equipment may be attached to the
structural element 2. Such a mounting of, for example, interior
details is considerably simpler to perform before the structural
element is mounted to the vehicle since a mounting inside the
vehicle always leads to a limited mounting space. Equipment,
which may be fixed to the structural element 2 internally, is, for
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example, fastening channels for seats and sound absorbing
panels.
Fig 2 shows schematically a cross sectional view of a structural
element 2 according to the present invention. The structural
element 2 thus comprises an external layer 5, an intermediate
layer 6 and an internal layer 7. Preferably, the external 5 and
internal 7 layers consist of metal sheets of, for example, steel or
aluminium, which layers essentially supply the supporting
properties to the structural element 2. However, it is possible to
manufacture the internal 7 layer in other materials such as, for
example, fibre reinforced plastic materials. The internal 7 layer
may also be performed in a more pliant material, such as
plywood, under the condition that the external 5 layer is
manufactured in an essentially stiffer material, such as, for
example, steel. Preferably, the intermediate layer 6 consists of a
stiff, thermal insulating material. Such a material may comprise
a foam plastic material of PVC, PMI, PEI or PUR. Alternative
materials for the intermediate layer 6 are balsa wood and other
materials having good thermal insulating properties. Preferably,
such thermal insulating materials may be formed in a honey
comb structure. The intermediate layer 6, which is essentially
thicker than the external 5 and internal 7 layers, is arranged to
provide both stiffness and thermal and sound insulating
properties to the structural element 2.
At the edges of the structural element 2, the material of
intermediate layer 6 may be in full view or covered by, for
example, a plastic material 10, in order to protect the material of
the intermediate layer 6 against, for example, damp.
The present invention is not in any way restricted to the
described embodiments but may be varied and modified within
the scopes of the claims.