U.S. patent application number 16/519666 was filed with the patent office on 2020-01-30 for spacer fabric and use thereof.
The applicant listed for this patent is Stefan MUELLER, Joachim WEIS. Invention is credited to Stefan MUELLER, Joachim WEIS.
Application Number | 20200032428 16/519666 |
Document ID | / |
Family ID | 69148704 |
Filed Date | 2020-01-30 |
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United States Patent
Application |
20200032428 |
Kind Code |
A1 |
MUELLER; Stefan ; et
al. |
January 30, 2020 |
SPACER FABRIC AND USE THEREOF
Abstract
A spacer fabric has two transversely spaced cloth layers. First
spacer yarns bridge and transversely connect the cloth layers and
are each formed by a core yarn and a helical wrapping made of metal
or having a metallic layer. Second spacer yarns also bridge and
transversely connect the cloth layers but are of different
construction from the first yarns.
Inventors: |
MUELLER; Stefan; (Wiehl,
DE) ; WEIS; Joachim; (Rauschenberg, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
MUELLER; Stefan
WEIS; Joachim |
Wiehl
Rauschenberg |
|
DE
DE |
|
|
Family ID: |
69148704 |
Appl. No.: |
16/519666 |
Filed: |
July 23, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
D10B 2401/16 20130101;
D10B 2403/021 20130101; D02G 3/12 20130101; D10B 2401/04 20130101;
D04B 21/14 20130101; D04B 1/14 20130101 |
International
Class: |
D02G 3/12 20060101
D02G003/12; D04B 21/14 20060101 D04B021/14; D04B 1/14 20060101
D04B001/14 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 27, 2018 |
DE |
102018118254.6 |
Claims
1. A spacer fabric comprising: two transversely spaced cloth
layers; and first spacer yarns that bridge and transversely connect
the cloth layers and that are each formed by a core yarn and a
helical wrapping made of metal or having a metallic layer.
2. The spacer fabric defined in claim 1, wherein the wrapping is
formed of metallic strip having a width and a thickness, a ratio of
the width to the thickness bing at least 5:1.
3. The spacer fabric defined in claim 2, wherein the strip is
flattened wire.
4. The spacer fabric defined in claim 3, wherein the wire is of
copper or has a coating of copper.
5. The spacer fabric defined in claim 2, wherein the strip is wound
helically around the core yarn and forms a plurality of spaced
turns between which the yarn is exposed.
6. The spacer fabric defined in claim 5, wherein the strip covers
30% to 95% of the core yarn.
7. The spacer fabric defined in claim 1, further comprising: second
monofilament spacer yarns that also bridge and transversely connect
the cloth layers but that are of different construction from the
first yarns. wherein the second spacer yarns are monofilaments.
8. The spacer fabric defined in claim 1, wherein the core yarn is a
multifilament yarn.
9. The spacer fabric defined in claim 1, wherein the cloth layers
and first and second spacer yarns are knitted.
10. The spacer fabric defined in claim 1, wherein a total thickness
of the spacer fabric is between 1 mm and 20 mm.
11. The spacer fabric defined in claim 1, wherein the core yarn has
a fineness between 50 dtex and 150 dtex.
12. The spacer fabric defined in claim 1, wherein the wrapping has
a cross-sectional area of between 200 .mu.m.sup.2 and 10,000
.mu.m.sup.2.
13. The spacer fabric defined in claim 1, wherein the first spacer
yarns have a cross-sectional shape that is not circular.
14. Use of the spacer fabric of claim 1 as a heat conduction
layer.
15. The use defined in claim 14, wherein the spacer fabric is
connected to an electrical component.
16. The use defined in claim 14, wherein the spacer fabric is in a
gap between a housing wall and the electrical component.
17. A method comprising the steps of: forming first yarns of a
multifilament nonconductive core yarn wrapped helically by a
conductive and flexible metal strip; providing second
monofilamentary yarns; and knitting together the first and second
yarns into a spacer fabric formed of two transversely spaced cloth
layers largely formed of the second yarns and bridged by first
spacer yarns formed by the first yarns and by second spacer yarns
formed by the second yarns.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a spacer fabric. More
particularly this invention concerns a knitted spacer fabric and a
use thereof.
BACKGROUND OF THE INVENTION
[0002] A typical spacer fabric comprises two usually substantially
flat or planar cloth layers and spacer yarns that transversely
bridge and interconnect the cloth layers. Some of the spacer yarns
and optionally even all of the spacer yarns having a core made of a
yarn and a spiral wrapping.
[0003] Spacer fabrics and, in particular, knitted spacer fabrics
are characterized by a light, air-permeable structure, with spacer
fabrics generally having an elasticity in the transverse direction
of their thickness as a result of spacer yarns that run between the
two cloth layers. By virtue of these properties, knitted spacer
fabrics are often provided as a soft, elastic layer that enables
air circulation in mattresses, upholstered furniture, garments, or
shoes. A conventional knitted spacer fabric is known from DE 90 16
062.
[0004] In addition to such conventional applications in the
consumer sector, spacer fabrics and, in particular, knitted spacer
fabrics are frequently also used as technical fabrics for highly
specialized applications. For instance, knitted spacer fabrics are
also used in the automotive industry, for example for
climate-controlled seats under the seat covers, with knitted spacer
fabrics allowing for good contour adjustment due to their
cushioning properties and very good restorative behavior despite
the overall low weight per unit area. Knitted spacer fabrics are
also used for the interior lining of vehicles, and it is even
possible to use them over air bags through the introduction of
local tear lines. The possible applications of knitted spacer
fabrics are not limited to the areas of ventilation and/or elastic
support. For instance, it is known from WO 2012/139142 to use
knitted spacer fabrics for railway sleepers for connecting a
concrete body to a sleeper pad, the knitted spacer fabric being
embedded partially in the concrete body and in the sleeper pad
during the manufacture of the sleeper body, thus enabling the
especially reliable, permanent connection of these two
elements.
[0005] Another known application is the provision of a heating or
sensor function, for which purpose wires and, in particular,
stranded wires are incorporated into the fabric structure.
Corresponding configurations are known from DE 19 903 070, DE 10
2008 034 937, and DE 10 2009 013 250.
[0006] According to DE 10 2015 114 778, a knitted spacer fabric is
proposed for heating purposes in which conductive yarns of a flat
knitted cloth layer are formed from a plastic multifilament yarn
provided with a conductive coating. The multifilament yarn has the
advantage that, despite the conductive and, in particular, metallic
coating of the individual filaments, it still has relatively good
flexibility, thus enabling processing in a knitting process. The
conductive yarns are exposed in at least the flat knitted layer
that is usually facing a user.
[0007] Another highly specialized application of a spacer knitted
fabric is known from US 2008/20299854 that also discloses a spacer
fabric with the above-described features. A spacer fabric with two
cloth layers and spacer yarns connecting the cloth layers is
described, the spacer yarns having a core that is made of a yarn
and a helical wrapping around the core. The knitted spacer fabric
is fire resistant to a certain extent. This property is achieved
particularly by the fact that the core is enclosed and protected by
the wrapping, for which purpose the wrapping is made of a
sufficiently insulating material wound up tightly around its core
yarn.
OBJECTS OF THE INVENTION
[0008] It is therefore an object of the present invention to
provide an improved spacer fabric.
[0009] Another object is the provision of such an improved spacer
fabric that overcomes the above-given disadvantages, in particular
that has a new functionality.
[0010] Another object is a preferred use of such a spacer
fabric.
SUMMARY OF THE INVENTION
[0011] A spacer fabric has according to the invention two
transversely spaced cloth layers. First spacer yarns bridge and
transversely connect the cloth layers and are each formed by a core
yarn and a helical wrapping made of metal or having a metallic
layer. Second spacer yarns also bridge and transversely connect the
cloth layers but are of different construction from the first
yarns.
[0012] In the context of the invention, a wrapping is thus provided
in at least the first spacer yarns that is made of metal or at
least has a metallic layer. A spacer fabric is thus provided that
is electrically and thermally conductive between the two cloth
layers transversely, i.e. in the direction of thickness. However,
the spacer yarns are not provided with a continuous sheath, which
would lead to substantial stiffening. In particular, the wrapping
can also be selected such that the spacer yarns can still be
processed easily during manufacturing of the spacer fabric, which
is not the case with solid or stranded metallic wires. The core of
the spacer yarns is formed by a yarn. In keeping with its general
meaning, the term "yarn" refers in this context to monofilaments,
multifilaments, or threads.
[0013] However, the core is especially preferably formed by a
multifilament yarn that is substantially softer and more flexible
than a monofilament yarn with the same fineness. Although the
metallic or metal wrapping does not form a closed surface and is
flexible, the metallic material stiffens the composite first yarns.
Particularly in this context, it can be advantageous if the core is
made of a multifilament yarn, even if poorer restorative properties
are produced in terms of a compression hardness as compared to a
monofilament yarns.
[0014] According to a preferred embodiment of the invention, in
order not to adversely affect the flexibility of the spacer yarns
that are provided with the wrapping and, beyond that, in order to
achieve good functional properties, the wrapping is strip-shaped
and has a width and a thickness with the ratio of the width to the
thickness being at least 5:1.
[0015] Several embodiments of such a strip-shaped material are
conceivable in principle. For example, the wrapping can be
separated in the form of a strip from a thin foil or another strip
stock. According to an especially preferred embodiment of the
invention, however, a wire is provided that is flattened and thus
formed into the flat strip. Such a reshaping of a round wire that
is usually flat at first is also referred to as flattening.
[0016] According to a preferred development of the invention, the
wrapping can be made of copper or have a layer of copper in the
interest of good thermal and/or electrical conductivity.
Particularly in consideration of material costs, copper is
preferable to more noble metals such as gold or silver, but these
materials and other metals can also be used in principle within the
scope of the invention.
[0017] In order to achieve long-term protection in the case of a
wrapping that consists substantially of copper, a covering layer of
tin can be provided provides protection from corrosion while not
impairing the thermal and/or electrical conductivity. In
particular, it is also possible to flatten tin-plated copper wire
as described above and thus to transform it into a strip-shaped
material without removing or damaging the tin coating.
[0018] As already explained above, the spacer yarns provided with
the wrapping retain a high degree of flexibility, because the
successive helical turns can still be moved and, in particular,
angled relative to one another.
[0019] According to a preferred embodiment of the invention, the
wrapping covers between 30% and 95% of the core yarn on its lateral
surface, particularly between 40% and 80%. This degree of coverage
provides good flexibility on the one hand while also providing
sufficient conductivity in terms of heat and/or electricity on the
other hand.
[0020] It is assumed that, in the usual embodiment of a core made
of a basically nonconductive polymeric yarn, not only the
electrical conduction but also the heat conduction takes place
substantially via the wrapping, which is metallic or has at least
one metallic layer.
[0021] It should also be noted in this regard that, due to the
helical shape of the winding, the effective length to be considered
for electrical conduction and heat conduction is substantially
greater than the length of the spacer yarn itself. With a typical
width and coverage of the wrapping, the length of wrapping in the
unwound or rectified state is between 1.5 and 4, preferably between
2 and 2.5 times greater than the length of the wrapped core yarn
itself. The spacer fabric, which is preferably embodied as a
knitted spacer fabric, is surprisingly characterized by very good
conductivity in terms of electricity and heat.
[0022] For example, the total thickness of the spacer fabric can be
between 1 mm and 20 mm, preferably between 2 mm and 10 mm. The
core, which is preferably made of multifilament yarn, preferably
has a fineness of between 50 dtex and 150 dtex.
[0023] As already explained above, the wrapping preferably is a
strip in order to be wound around the core in a helical manner with
the smallest possible thickness. In order to ensure sufficient
stability on the one hand and good processability on the other
hand, and in order to provide the desired conductive properties,
the wrapping preferably has a cross-sectional area of between 200
.mu.m.sup.2 and 10,000 .mu.m.sup.2, especially preferably between
600 .mu.m.sup.2 and 40 .mu.m.sup.2.
[0024] The two flat cloth layers are not limited in their specific
design. Preferably, the flat cloth layers are made of polymeric
yarns and are also preferably free of metal and thus electrically
non-conductive and thermally insulating.
[0025] In an embodiment as a knitted spacer fabric, different
laying patterns are possible, and openings can also be provided in
the cloth layers, each of which is formed by a plurality of
stitches.
[0026] Particularly if the cloth layers are made of nonconductive
yarns according to a preferred embodiment of the invention, it can
be advantageous if the spacer yarns are integrated into the cloth
layers so that they are exposed to or even protrude beyond the
outer faces of the spacer fabric. At the same time, the fact that
the wrapping of the spacer yarns results in a certain stiffening
can also be advantageously exploited, so that they are less
strongly angled in the stitch formation. In particular, the first
spacer yarns provided with the wrapping can be adjusted in the same
way through suitable selection of the core on the one hand and of
the wrapping on the other hand, that the first spacer yarns still
have good processability but also have a certain strength and
rigidity at the same time.
[0027] In the context of the invention, both the first and the
second spacer yarns can be provided with the wrapping in the manner
described.
[0028] According to an alternative, preferred embodiment of the
invention, the first spacer yarns have core yarns with helically
wound wrapping, while a second portion of the spacer yarns is
provided without wrapping.
[0029] The proportion of the number of one of the spacer yarns to
the total number of the first plus the second spacer yarns in a
given area is typically between 10% and 90%, preferably between 30%
and 70%. The second spacer yarns are especially preferably made of
monofilament yarn in order to impart good elastic properties and
good compression hardness to the spacer fabric. In the context of
such an embodiment, a functional division then takes place between
the first spacer yarns and the second spacer yarns.
[0030] According to an embodiment of the invention, the spacer
yarns can be deformed after they are wrapped in order to stabilize
the spacer yarns provided with the winding to some extent. As with
the flattening of a wire to form the wrapping, the yarns provided
with the wrapping can be flattened between rolls prior to
processing, i.e. particularly knitting, in which case the spacer
yarns are given an approximately oval cross-sectional shape. By
virtue of such an oval, flatly pressed cross section, the structure
of the first spacer yarns is stabilized on the one hand and, on the
other hand, the flexibility in the spacer fabric formed is reduced.
In particular, this can prevent the spacer yarns from twisting or
the wrapping from twisting relative to the core.
[0031] The spacer fabric according to the invention can be provided
in an especially advantageous manner as a heat-conduction layer,
for best service as the preferred use with an electrical or
electronic component.
[0032] The knitted spacer fabric is characterized by a particularly
light structure, but good heat transfer is possible in the
transverse direction of thickness. It is also of particular
advantage that the spacer fabric is elastic in the direction of
thickness. For example, the spacer fabric can also be used in gaps
and cracks in order to allow heat transfer there.
[0033] Such an arrangement is advantageous particularly if
electrical components are to be cooled in a housing. For example,
if rechargeable batteries, motors, and other electrical components
are placed in a housing with an ohmic resistance, the spacer fabric
can be used for heat transfer in such installation situations.
Optionally, an adhesive, a paste, or the like can be used on the
cloth layers for better fixation and/or contacting, it being
possible even then for thickness compensation or thickness
adjustment to be performed by the spacer yarns. Different gap
dimensions due to production-related fluctuations can be
compensated for by the knitted spacer fabric in a particularly
advantageous manner, and because of the low weight per unit area
compared to known designs, weight savings can often also be
achieved. Especially for the described applications, the heat
conduction is sufficient despite the overall airy structure.
[0034] Finally, applications are also conceivable in which the
cooling is improved even further through ventilation of the spacer
fabric, so that a cooling by convection or a cooling air flow then
also occurs in addition to the heat conduction via the
thickness.
[0035] One specific application in which the advantages described
above are especially evident is for an electrical component fitted
in a housing, in which case small gaps may remain due to assembly.
The electrical component can be a motor, a rechargeable battery
module, an inverter, or the like. In this context, it should also
be noted that, particularly with regard to the storage of electric
current for mobile applications such as electric vehicles or in
connection with photovoltaic systems, increasing demand exists for
corresponding electrical components, with weight minimization being
desired particularly for mobile use.
BRIEF DESCRIPTION OF THE DRAWING
[0036] The above and other objects, features, and advantages will
become more readily apparent from the following description,
reference being made to the accompanying drawing in which:
[0037] FIG. 1 is a perspective view of a piece of a knitted spacer
fabric or fabric according to the invention;
[0038] FIG. 2 is a larger-scale view of a detail of the fabric of
FIG. 1;
[0039] FIG. 3 is a view of a short piece of a spacer yarn of the
knitted spacer fabric according to FIG. 1 that is made of a yarn
and a wrapping;
[0040] FIGS. 4a to 4c shows method steps for forming the spacer
yarn of this invention; and
[0041] FIG. 5 is a schematic view of a rechargeable battery module
in a housing.
SPECIFIC DESCRIPTION OF THE INVENTION
[0042] FIG. 1 shows a spacer fabric in the form of a knitted spacer
fabric with two cloth layers 1 and first and second spacer yarns 2a
and 2b that extend transversely between the planes of and connect
the layers 1. FIG. 1 and the detail view of FIG. 2 show that the
spacer yarns 2a and 2b are configured differently. The first spacer
yarns 2a each have a core 3 formed by a multifilament yarn and a
helical wrapping 4 around the core 3. The wrapping 4 is made of
metal or has at least one metallic layer.
[0043] It can already be seen from the detailed view of FIG. 2
that, if desired, good electrical conduction can also be achieved
by the metallic wrapping 4 transversely, in the direction of
thickness, the other spacer yarns 2b are formed of polymeric
monofilaments.
[0044] The different spacer yarns 2a and 2b extend similarly
between the two cloth layers 1 and also are of a similar thickness.
While the metal-wrapped first spacer yarns 2a ensure good
conduction of heat and electricity, the second spacer yarns 2b can
provide the compression hardness and elastic recovery that are
typical of a spacer fabric and particularly a knitted spacer
fabric.
[0045] The exact configuration of the first spacer yarns 2a
provided with the sheath 4 can be seen from the sectional view of
FIG. 3. In the illustrated embodiment, the core 3 is a
multifilament yarn with for example a fineness of 76 dtex.
Polyethylene terephthalate is particularly suitable as the
material, but other typical materials such as various polyolefins,
polyamide, and the like can also be employed.
[0046] It can be seen from FIG. 3 that the wrapping 4 has a
strip-shaped configuration with a width b and a thickness d, the
ratio of the width b to the thickness d being at least 5:1. In the
illustrated embodiment, the wrapping 4 is made of tinned copper, it
being possible for an initially circular-section tinned copper wire
to be flattened in order to form the strip-shaped configuration.
Such a method step is shown by way of example in FIG. 4a.
[0047] It is also apparent from FIGS. 2 and 3 that there is a gap
between the successive turns of the wrapping 4, 30% and 95% of the
core being covered.
[0048] The helical wrapping 4 also has the effect that the
effective length for heat conduction or electrical conduction of
the wrapping 4 is greater than the length of the core. In the
unwound state, the wrappings 4 typically have a length that is 2 to
2.5 times greater than that of the respective core yarns 3. Despite
this increased path length, very good conduction of heat is
observed overall.
[0049] For example, the wrapping can have a cross-sectional area of
between 200 .mu.m.sup.2 and 10,000 .mu.m.sup.2, particularly
between 600 .mu.m.sup.2 and 4000 .mu.m.sup.2. The multifilament
yarn that is here provided as the core 3 can have 24 or 36
filaments, for example.
[0050] FIG. 4b indicates how the core 3 of multifilament yarn can
be provided with the wrapping 4. Finally, FIG. 4c shows that the
first spacer yarns 2a can also be flattened to some extent before
the knitting process to stabilize their cross-sectional shape and
wrapping.
[0051] The spacer fabric according to the invention is provided in
an especially advantageous manner as a heat conduction layer, it
being also optionally possible for ventilation to take place
through it. In this context, the highly schematic representation of
FIG. 5 shows the arrangement of a rechargeable battery module 5 in
a housing 6, with the spacer fabric forming an intermediate layer 7
between the outer surface of the module Sand the inner surface of
the housing 6. In particular, this spacer fabric as an intermediate
layer 7 can be used to compensate for a remaining gap between the
rechargeable battery module 5 and the housing 6. It should also be
noted that the actual gap to be bridged can vary greatly due to
manufacturing-related variations. Particularly in this context, the
invention offers the advantage that the spacer fabric can be
compressed when used as a heat conduction layer and also resets
elastically to a certain extent. Such compensation is not possible
with a thermally conductive paste or other compact media.
* * * * *