U.S. patent application number 11/462094 was filed with the patent office on 2007-02-08 for electrical heating module for air flow heating, in particular for heating and ventilation of seats.
This patent application is currently assigned to MicroHellix Systems GmbH. Invention is credited to Ingo Schehr.
Application Number | 20070029253 11/462094 |
Document ID | / |
Family ID | 35502211 |
Filed Date | 2007-02-08 |
United States Patent
Application |
20070029253 |
Kind Code |
A1 |
Schehr; Ingo |
February 8, 2007 |
ELECTRICAL HEATING MODULE FOR AIR FLOW HEATING, IN PARTICULAR FOR
HEATING AND VENTILATION OF SEATS
Abstract
An electric heating module for heating an air flow, in
particular for heating and ventilating seats is provided, having at
least one PTC-heating element 8 and at least one heat dissipation
area 2 adjacent thereto that allows air to flow therethrough,
having heat-conducting ribs 1, which are in an effective connection
to the PTC-heating element 8 and combined therewith to form a
module. The heat-conducting ribs 1 are formed from strips, which
are combined in the area of the PTC-heating element 8 to form at
least one packet of strips 3 formed by ribs 1 being in a
heat-conducting contact to one another, while they are fanned out
in the heat dissipation area 2.
Inventors: |
Schehr; Ingo; (Jockgrim,
DE) |
Correspondence
Address: |
VOLPE AND KOENIG, P.C.
UNITED PLAZA, SUITE 1600
30 SOUTH 17TH STREET
PHILADELPHIA
PA
19103
US
|
Assignee: |
MicroHellix Systems GmbH
Carl-Zeiss Strasse 4-6
Olbronn-Durrn
DE
75248
|
Family ID: |
35502211 |
Appl. No.: |
11/462094 |
Filed: |
August 3, 2006 |
Current U.S.
Class: |
210/603 |
Current CPC
Class: |
F24H 3/0405 20130101;
F24H 3/0482 20130101; B60H 2001/229 20130101; F24H 9/1863 20130101;
B60H 2001/2271 20130101; F24H 3/0464 20130101; F24H 3/0476
20130101; B60H 1/2225 20130101; F24H 3/0435 20130101 |
Class at
Publication: |
210/603 |
International
Class: |
C02F 3/00 20060101
C02F003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 6, 2005 |
DE |
20 2005 012 394.3 |
Claims
1. An electrical heating module for heating an air flow for heating
and ventilating seats, comprising at least one PTC-heating element
(8) and at least one heat dissipation area (2) adjacent thereto
which allows air to flow therethrough, with heat-conducting ribs
(1), which are in an effective connection to the PTC-heating
element (8) and are combined together to form a module, the
heat-conducting ribs (1) are formed from strips, which are combined
in an area of the PTC-heating element (8) to form at least one
packet of strips (3) formed by the ribs (1) in a heat-conducting
contact with one another, and which are fanned out in the heat
dissipation area (2).
2. An electric heating module according to claim 1, wherein the
heat dissipation area (2) is generally circular and encircles an
area of the PTC-heating element (8) in a plane aligned
approximately perpendicular to the air flow.
3. An electric heating module according to claim 1, wherein the
PTC-heating element (8) is located between two packets of the
strips (3) and contacts them both in a heat-conducting as well as
an electrically conducting manner, and an electrically insulating
frame material (5) is arranged between the two packets of strips
(3), into which the PTC-heating element (8) is integrated, and the
PTC-heating element (8) is supplied with power via the packets of
strips (3).
4. An electric heating element according to claim 3, wherein the
frame element (5) is provided in the form of a rib (1) that extends
into the heat dissipation area (2).
5. An electric heating module according to claim 4, wherein the
frame element (5) is provided with assembly elements (6) for
mounting to a housing (14) for the module.
6. An electric heating module according to claim 4, wherein contact
bars (7) are provided in or at the packets of strips (3) for
supplying power to the PTC-heating elements (8).
7. An electric heating module according to claim 3, wherein the
PTC-heating element (8) is surrounded by a soft-elastic sealing
layer located in the electrically insulating frame element (5).
8. An electric heating element according to claim 7, wherein the
soft-elastic sealing layer is an O-ring (11) or a soft-elastic
component of a material which forms the frame element.
9. An electric heating module according to claim 3, wherein the
packets of strips (3) are held together by a welding seam (4).
10. An electric heating module according to claim 1, wherein the
heat conducting ribs (1) comprise aluminum or copper sheet metal
strips.
11. An electric heating module according to claim 10, wherein the
sheet metal strips are provided with centering bores (12) for a
correctly positioned stacking during assembly.
12. An electrical heating module according to claim 1, wherein the
packets of strips (3) are compressed against one another by a
spring-loaded clamp (13).
13. An electric heating module according to claim 5, wherein the
housing (14) forms a cylindrical or conical air flow channel, in
which the heating module and, an axial or diagonal fan (15) is
located downstream and/or upstream of the heating module.
14. An electric heating module according to claim 13, wherein the
axial or diagonal fan (15) is positioned in a fan housing (18) of
its own, which is accepted in the housing (14).
15. An electric heating module according to claim 1, wherein the
heating module is connected to a ventilated seat to provide an air
flow that can be heated to the seat.
16. An electric heating module according to claim 15, wherein the
seat is a vehicle seat.
Description
BACKGROUND
[0001] The invention relates to an electrical heating module for
heating air flow according to the preamble of claim 1. This heating
module is particularly used for heating and ventilation of seats.
It comprises essentially at least one PTC-heating element and at
least one heat dissipation area adjacent thereto having
heat-conducting ribs, through which air can flow, effectively
connected to the PTC-heating element and combined with them to form
a single module.
[0002] PTC-elements are semi-conductor resistors made from
ceramics, with their active resistance varying depending on
temperature. The characteristic resistance-temperature line does
not progress linearly: the resistance of a PTC-heating element
initially reduces slightly with an increasing temperature of the
component in order to, then, rise very rapidly at a characteristic
temperature (reference temperature). This overall positive
progression of the characteristic resistance-temperature line
(PTC=positive temperature coefficient) leads to a PTC-heating
element having self-adjusting features. At a component temperature
distinctly lower than the reference temperature the PTC-heating
element has a lower resistance so that appropriately high current
can be conducted through it. When a good heat dissipation from the
surface of the PTC-heating element is ensured, an appropriately
high electric charge is accepted and released in the form of heat.
However, when the temperature of the PTC-heating element exceeds
the reference temperature, the PTC-resistance increases rapidly so
that the electric power draw is limited to a very low value. The
temperature of the component then approaches an upper limit, which
depends on the heat absorption of the environment of the
PTC-heating element. Under normal environmental conditions, the
temperature of the component of the PTC-heating element can
therefore not exceed a characteristic maximum temperature, even
when the intended heat dissipation is entirely interrupted in a
malfunction. This fact and the self-adjusting features of a
PTC-heating element, based on which the drawn electric power is
precisely equivalent to the thermal power dissipated, predestines
PTC-heating elements for the use in heating and/or air conditioning
arrangements of vehicles or in other applications of air flow
heating in vehicles. For safety reasons, in this application field
even in the case of a malfunction no flammable temperatures may
develop in the heating element, although in normal operation high
heating output is required.
[0003] In order to heat the interior compartment of motor vehicles
it has been known to use electric heating modules having a frame,
which forms a module by combining a multitude of PTC-heating
elements and adjacent heat dissipating areas, through which air can
flow, having heat-conducting ribs. An example for such electric
heating modules known is found in EP 0 350 528 A1.
[0004] In EP b 1 479 918 A1 a complete fan module, comprising a
radial fan integrated in a housing and a heating module of the type
mentioned at the outset, is disclosed serving to heat the seat in a
ventilated vehicle seat. Due to the fact that, for safety reasons,
a vehicle seat may not exceed a maximum temperature at its surface,
suitable for human beings, heating modules with PTC-heating
elements are excellently suitable, even in case of a ventilator
malfunction, because, while they provide the same level of safety,
they can release a considerably higher heating power than mats
conventionally used in heated seats with electric resistance wires,
whose power draw is very limited for safety reasons.
[0005] The previously known electric modules of the type mentioned
at the outset generally comprise several layers of planar
PTC-heating elements, arranged side-by-side, with their narrow
sides being in the line of the air flow, with their flat upper
sides and their lower sides each electrically contacting contact
metal sheets. The heat dissipation areas adjacent thereto are
provided with meandering metal ribs, which are also located with
their narrow sides in line with the air flow and thermally contact,
supported at their broad side, the contacting metal sheets of the
PTC-heating elements in regular intervals for heat transfer. In
order to achieve a good heat transfer from the PTC-heating elements
to the heat conducting ribs, a heat conducting glue or other
connection techniques can be used; however, a more efficient
solution has become widely accepted, i.e. to insert the PTC-heating
elements and the heat conducting bars into a frame, combining them
into a module, and to provide at least one spring element in the
frame, which presses the alternating arranged heat dissipation
areas with the heat conducting bars and the bars with the
PTC-heating elements against one another.
[0006] However, this requires a rectangular shape of the electric
heating module with cellular structures of the components, which is
not the best choice with respect to the aerodynamics for heating
air, particularly when the space for the respective air-flow
conducting channels is very limited, as is the case in motor
vehicles. Therefore, it was logical for the ventilator module for
vehicle seats according to EP 1 479 918 A1 to use a radial
ventilator. However, it is known that radial ventilators are not
particularly suitable for this purpose, because they create high
pressure with respectively high exiting flow speeds.
[0007] Furthermore, an automated production of the known electric
heating modules is hardly possible due to their multi-layered,
spring-loaded structure within a frame. Rather, a high degree of
manual labor is necessary.
[0008] Another example for a ventilator module for motor vehicle
seats is found in EP 1 464 533 A1. U.S. Pat. No. 6,541,757 B1 shows
an example for a heating module provided with a blower and
resistance heating wires in the air flow, like in hair dryers, and
integrated in a vehicle seat.
SUMMARY
[0009] Starting with this prior art, the present invention is based
on the objective of improving an electric heating module of the
type mentioned at the outset with regard to automated
manufacturing.
[0010] This objective is attained by an electric heating module
having the features of claim 1. Preferred embodiments and further
embodiments of the invention are described in claims 2 through 14.
A preferred use of the heating module according to the invention is
found in claim 15.
[0011] According to the present invention an electric heating
module of the type mentioned at the outset is modified in that the
heat conducting ribs are formed from strips, which are connected in
the area of the PTC-heating element into at least one packet of
strips. This packet of strips is formed from bars being in a
heat-conducting contact to one another, while the strips in the
heat dissipation area are fanned out such that air can flow through
them. The heat transfer from the PTC-heating element into the ribs
occurs therefore in an area, in which the ribs are combined to a
compact packet and act as a massive block, in which the heat of the
PTC-heating element distributes rapidly. Where the ribs extend into
the heat dissipation area they are fanned, through, i.e. each being
at a distance from one another, by being increasingly angled at the
transfer section to the heat dissipation area towards the edge
regions of the packet of strips. Good heat conduction occurs within
the individual ribs so that the heat in the heat dissipation area
can be released very efficiently to the air flowing through.
Simultaneously, the production of such strips in the form of ribs
and combining them to packets of strips as well as the fanning of
the ribs in the heat dissipation area allow it to be produced
entirely in an automated fashion and furthermore makes it very
efficient and cost effective.
[0012] The fanning of the heat conducting ribs formed from strips
according to the invention, starting from the area of the
PTC-heating element, in which the ribs are combined to packets of
strips, naturally causes a fan-shaped arrangement of the ribs in
the heat dissipation area so that it has a beneficially curved
shape. Particular advantages result from the heat dissipation area
being embodied accordingly in a circular shape, in particular
round, and surround the area of the PTC-heating element in a plane
positioned approximately perpendicular to the air flow. Thus, in
this circular heat dissipation area the ribs extend essentially
radially so that the electric heating module according to the
invention can be inserted into a cylindrical, aerodynamically
beneficial air flow channel or a respective pipe. In this manner, a
very homogenous flow through the heat dissipation area is ensured
without forming heat pockets, such as e.g. in the corners of a
conventionally rectangular, cellular arranged heating module. But
primarily a heating module with a circular heat dissipation area is
suitable for an efficient combination with an axial or diagonal
fan; this can be inserted very easily in front or behind the
heating module according to the invention in order to form a
ventilating heater safe from overheating.
[0013] The PTC-heating element can be located between two packets
of strips and contact them not only in a heat-conducting fashion
but also electrically conducting. When simultaneously an
electrically insulating frame element is provided, which is
arranged between the two packets of strips and accepts the
PTC-heating element, the PTC-heating element can be supplied with
power via the packets of strips. This occurs simply in that the
first packet of strips is located at one side of the PTC-heating
element and connected to the other electrical potential than the
other packet of strips at the other side of the PTC-heating element
so that the current can flow through the PTC-heating element
necessary for heating it. In this way, the PTC-heating element can
be integrated in the packet of strips in a very compact fashion, in
particular assembled therein in an automated manner, so that
respective advantages result with regard to a compact construction,
efficient heat transfer, as well as easy automatic
manufacturing.
[0014] The electric insulating frame element can not only separate
the packet of strips from one another, but can also be embodied in
the form of a rib and extend into the heat dissipation area. This
way it is ensured that in the heat dissipation area no unintended
electrically conducting bridge can develop between the ribs of one
packet of strips and ribs of the other packet of strips.
Additionally, the frame element can then be provided with assembly
elements for connecting them to a housing for the module, which
again facilitates the automatic machine production.
[0015] In this context it must be mentioned that, of course, in a
heating module according to the invention three or more packets of
strips having PTC-heating elements positioned therebetween and, if
necessary, corresponding electrically insulating frame elements can
be combined to a single module as well.
[0016] In order to electrically contact the PTC-heating element,
contacting links can be arranged in or at the packets of strips,
which are connected to the power supply. This also increases the
potential level of automation during the machine production of the
heating module according to the invention.
[0017] When an electrically insulating frame element is provided
between the packet of strips, in which the PTC-heating element is
integrated it is preferred for the PTC-heating element to be
surrounded by a soft-elastic sealing layer located in the
electrically insulating frame element. This soft-elastic sealing
layer may comprise an O-ring, which again facilitates the
production enormously, or a soft-elastic component of the material
of the frame element. In the latter case, the frame element could
be produced, for example, from plastic, using a two-component
injection technique. In addition to the mechanical protection for
the PTC-heating element during the assembly, such a soft-elastic
seal also offers protection from moisture, which can be rather
important for a heating module to be mounted in a seat.
[0018] The heat-conducting ribs preferably comprise aluminum or
copper sheet metal strips. Said materials offer high heat
conductivity and can be processed rather easily in an automated
fashion.
[0019] The packets of strips, to which the heat-conducting ribs are
combined in the area or the PTC-heating element, are preferably
held together by welding, for example using a laser welding seam or
the like. Additionally, the packets of strips can be pressed toward
one another by a spring-loaded clamp. This spring-loaded clamp can
preferably hold not only the respective packets of strips but all
packets of strips with the PTC-heating element located therebetween
and compress them such that the heat exchange between the
PTC-heating element and the packets of strips as well as between
the individual ribs is optimized.
[0020] For a simple and accurately positioned machine production,
the ribs embodied as strips can additionally be provided with
centering bores for a correctly positioned stacking during the
assembly.
[0021] When a housing is provided, into which the electric heating
module according to the invention is integrated, it is preferred
for said housing to form a cylindrical or, for the purpose of noise
reduction, a conical air flow channel, in which the heating module
and downstream and/or upstream in reference to a heating module, an
axial or diagonal fan is accepted.
[0022] The axial or diagonal fan can be a conventional fan with a
fan housing and electric connectors, so that it is useful for the
housing of the heating module according to the invention to accept
the axial or diagonal ventilator including its own ventilator
housing.
[0023] A particular advantage of the electric heating module
according to the present invention results when it is used as a
ventilator in a ventilated seat, in particular a vehicle seat, in
which the heating of the airflow can be switched on, if necessary,
to serve as a seat heater using the PTC-heating element and the
heat conducting ribs.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] In the following, an embodiment of the present invention is
described and explained in greater detail using the attached
drawing. It shows:
[0025] FIG. 1 a perspective view of a heating module according to
the invention;
[0026] FIG. 2 a top view of the heating module of FIG. 1;
[0027] FIG. 3 a perspective exploded view of the heating module of
FIG. 1;
[0028] FIG. 4 a heating module of FIG. 1 with a housing and fan,
prior to the assembly;
[0029] FIG. 5 the heating module assembled in the housing in a
perspective top view;
[0030] FIG. 6 a perspective view of the heating module assembled in
the housing, seen from below.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0031] The completely assembled exemplary embodiment of an electric
heating module according to the present invention, shown in a
perspective view in FIG. 1, comprises a multitude of
heat-conducting ribs 1, made from aluminum sheet metal strips and
radially filling a circular heat dissipation area 2. In the center
of the heat dissipation area 2 the heat conducting ribs 1 are
combined to a total of four packets of strips 3, with the ribs 1 of
each packet of strips 3 being closely packed and contacting one
another in a heat conducting and electrically conducting manner.
Using welding seams 4 the ribs 1 of the individual packets of
strips 3 are fixed to one another.
[0032] Two electrically insulating frame elements 5 are arranged
between the packets of strips 3, which insulate the two central
packets of strips 3 each from the exterior packets of strips 3. The
frame elements 5 extend from the central area inside the heat
dissipation area 2 towards the heat dissipation area 2 and continue
towards the assembly elements 6, at which a housing and a fan can
be attached, as described below.
[0033] The two central packets of strips 3 are only separated from
one another by a contact bar 7, by which the PTC-heating elements
(here not shown) integrated in the frame elements 5 can be
connected to a power supply (not shown). Additional contact bars 7
are provided at the edge region of the exterior packet of strips 3
in order to also connect the respective other contact surfaces of
the PTC-heating elements to the power supply.
[0034] The electrical contacting is illustrated with charge symbols
in FIG. 2, which is a top view of the electrical heating module of
FIG. 1. The central contact bar 7, symbolized with a plus sign, is
switched to another electric potential than the two exterior
contact bars 7, which are marked with a minus sign. Due to the fact
that the ribs 1 in the central area around the two PTC-heating
elements located in the frame elements 5 are supported on one
another over their entire surface they not only form a good heat
conductor but also a good electric conductor so that the current
from the contact bars 7 reach the PTC-heating elements via the
packets of strips 3. The electrically insulating frame elements 5
ensure that no short can develop in the area of the packets of
strips 3 or in the heat release area 2.
[0035] In FIG. 3, an exploded view of FIG. 1, it is discernible how
the two now visible PTC-heating elements 8 are integrated in the
frame elements 5. The frame elements 5, additionally provided at
the top and the bottom with assembly frames 9 for an exact
positioning, are provided with a circular recess 10, into which the
PTC-heating elements 8 and an O-ring 11 can be inserted in a
form-fitting manner. The heat-conducting ribs 1 are combined to
packets of strips 3 in their central areas, while they radially fan
out in the heat dissipation area 2. The packets of strips 3 are
fixed via welding seams 4. The ribs 1 are provided with central
bores 12, by which they can be stacked exactly in order to form the
packets of strips 3. After the assembly of the four packets of
strips 3 and the two frame elements 5 with the two PTC-heating
elements 8 as well as the assembly therebetween and/or
superimposition of the contact bars 7 the entire module is finally
fixed with the spring-loaded clamp 13. In addition, the
spring-loaded clamp 13 permanently presses the packets of strips 3
towards one another so that the packets of strips 3 positioned at
both sides of the PTC-heating elements 8 are pressed against the
PTC-heating elements in order to ensure an optimal contact.
[0036] Using the FIGS. 1 through 3, it is discernible that the
heating module according to the invention can be very easily
assembled, in particular assembled and produced automatically by
machines without any problems. As described in the following, the
insertion into a housing and the attachment of a fan are also
possible very easily just as the electrical contact of the module
via the contacting bar 7.
[0037] FIG. 4 shows a perspective view of the electric heating
module of FIGS. 1 through 3, a housing 14, and an axial fan 15
prior to their assembly. The axial fan 15 comprises a commercial
axial fan with a rotor 16, a motor 17, and a housing ring 18. The
housing 14 comprises a cylindrical heat exchange area 19, a
cylindrical fan area 20, and an air output opening 21, which is
provided with air directing bars 22. A type of assembly flange 23,
having centering pins 24, is formed at the housing 14. In order to
allow the axial fan 15 to be inserted together with its housing 18,
without having to modify it, the ventilator area 20 is expanded in
reference to the heat exchange area 19, into which the heating
module is to be inserted. For this purpose, the assembly elements 6
of the frame element 5 serve to fix the housing ring 18 of the
axial fan 15 in the right position in reference to the ribs 1 and
to hold them fixed in the housing 14. An opening 25 in the housing
serves to guide cables for the power supply of the motor 17 of the
axial fan 15 as well as to connect the PTC-heating elements via the
contact bars 7 to the power supply.
[0038] In the FIGS. 5 and 6, perspective representations of the
assembled arrangement of FIG. 4 are shown from the top and the
bottom. Using these drawings, the present invention shows the
compact and easily automatically assembled construction of the
ventilator with air flow heating, in particular for an assembly
into ventilated seats. Simultaneously, using the FIGS. 1 through 6,
it is discernible that the heating module according to the
invention can be automatically produced and assembled without any
problems with a very high degree of automation. The housing 14,
shown in FIGS. 5 and 6 and provided with an electric heating module
and an axial fan 15, can be used both for ventilation, for example
of a vehicle seat, or when the PTC-heating element is activated,
for heating of a seat with a very efficient air flow heating, with
the air flow heater being provided with heat-conducting ribs 1
arranged radially, with a circular heat dissipation area 2
producing a very even temperature distribution in the housing 14,
and ultimately in the seat. Due to the particulars of the
PTC-heating elements, here a very high initial power is provided
for heating, while due to the positive temperature characteristic
the PTC-heating elements ensure a tolerable maximum temperature
under all circumstances, i.e. even during malfunctions.
* * * * *