U.S. patent application number 09/861872 was filed with the patent office on 2002-01-31 for electric heating device, especially for use in motor vehicles.
This patent application is currently assigned to CATEM GmgH & Co. KG. Invention is credited to Beetz, Klaus, Bohlender, Franz.
Application Number | 20020011484 09/861872 |
Document ID | / |
Family ID | 8168820 |
Filed Date | 2002-01-31 |
United States Patent
Application |
20020011484 |
Kind Code |
A1 |
Beetz, Klaus ; et
al. |
January 31, 2002 |
Electric heating device, especially for use in motor vehicles
Abstract
The present invention relates to an electric heating device
which is especially conceived as a heating device for use in
automotive vehicles. A plurality of heating elements, which are
stacked so as to define a heating block, form together with a
control device a structural unit. For this purpose, the control
device is accommodated in a lateral bar of the frame by means of
which the heating elements are held together. The air to be heated
flows through the heating block as well as through windows provided
in the lateral bar, past cooling elements which are respectively
connected to the power-electronics components of the control
device.
Inventors: |
Beetz, Klaus; (Karlsruhe,
DE) ; Bohlender, Franz; (Kandel, DE) |
Correspondence
Address: |
DARBY & DARBY
805 THIRD AVENUE, 27TH FLR.
NEW YORK
NY
10022
US
|
Assignee: |
CATEM GmgH & Co. KG
|
Family ID: |
8168820 |
Appl. No.: |
09/861872 |
Filed: |
May 21, 2001 |
Current U.S.
Class: |
219/530 ;
219/202; 219/540 |
Current CPC
Class: |
B60H 1/2225 20130101;
H05B 3/50 20130101; H05K 1/0204 20130101; F24H 3/0441 20130101;
F24H 9/1872 20130101; H05B 1/0236 20130101; F24H 3/0429 20130101;
H05B 2203/02 20130101; B60H 1/2218 20130101 |
Class at
Publication: |
219/530 ;
219/540; 219/202 |
International
Class: |
H05B 003/22 |
Foreign Application Data
Date |
Code |
Application Number |
May 23, 2000 |
EP |
00111120.2 |
Claims
1. An electric heating device, especially for use as a
supplementary electric heating for motor vehicles, comprising: a
plurality of heating elements (2) which are combined so as to form
a heating block, said heating block being held in a rectangular
frame (3, 4, 5), and a control device for controlling the heating
elements (2), said control device defining a structural unit with
the heating block held in the frame (3, 4, 5) and being provided
with power transistors (11) which are arranged on a printed circuit
board (10) and which are each provided with a cooling element (6),
wherein the frame is defined by opposed longitudinal bars (3) and
lateral bars (4, 5) arranged at right angles to said longitudinal
bars (3), at least one of said lateral bars (5) is implemented as a
box which is open on one side thereof and which is adapted to have
the control device inserted therein, window openings (7) are
provided in said lateral bar (5) and the cooling elements (6) of
the power transistors (11) are located between respective opposed
window openings (7) in the inserted condition of the control
device.
2. An electric heating device according to claim 1, wherein means
(17) for influencing the air current are provided between said
opposed window openings (7).
3. An electric heating device according to claim 1, wherein the
cooling elements (6) are each U-shaped and wherein the respective
opposed legs of the cooling elements (6) are arranged adjacent the
window openings (7) in the inserted condition of the control
device.
4. An electric heating device according to claim 3, wherein
air-conducting means (17) are provided between said opposed window
openings (7), said air-conducting means projecting between the legs
of the U-shaped cooling elements (6).
5. An electric heating device according to one of the claims 1,
wherein each cooling element (20) has a pin (20a) which, extending
through an opening provided in the printed circuit board (10),
establishes a connection between said cooling element (20) and the
transistor (19).
6. An electric heating device according to one of the claims 1,
wherein each of the cooling elements (20) is secured in position by
means of a spring (21).
7. An electric heating device according to one of the claims 2,
wherein the window openings (7) and/or the means (17) for
influencing the air current are implemented such that air can flow
around components of the control device which are located on the
printed circuit board (10).
8. An electric heating device according to one of the claims 1,
wherein the printed circuit board (10) of the control device is
equipped with components on only one side thereof.
9. An electric heating device according to one of the claims 1,
wherein the printed circuit board (10) is arranged at right angles
to the plane of the frame and is implemented such that its length
corresponds substantially to that of the lateral bar (5).
10. An electric heating device according to one of the claims 1,
wherein the control device is adapted to be fixed in the lateral
bar (5) by means of electric connection lugs (15) which project
from the heating elements (2) into the interior of said lateral bar
(5).
11. An electric heating device according to claim 10, wherein
spring elements (14) for receiving the connection lugs (15) are
provided on the printed circuit board (10), said spring elements
(14) being complementary to the connection lugs (15).
12. An electric heating device according to one of the claims 1,
wherein the open side of the box-shaped lateral bar (5) can be
closed by means of a plug-on or clip-on cover.
12. An electric heating device according to one of the claims 1 to
11, wherein the open side of the box-shaped lateral bar (5) can be
closed by means of a plug-on or clip-on cover.
Description
[0001] The present invention relates to an electric heating device
for heating air, which is especially suitable for use as a
supplementary electric heating in motor vehicles.
[0002] In motor vehicles heating devices or radiators are used for
heating the vehicle interior and/or the engine. On the one hand,
they are used when the engine is started, as long as the engine
does not yet provide sufficient heat energy. On the other hand,
especially consumption-optimized internal combustion engines make
it necessary to use such heating devices in motor vehicles.
[0003] The use of such heating devices is, however, not restricted
to the field of automotive vehicles. These heating devices are also
suitable to be used for a great variety of other purposes, e.g. in
the field of domestic installations (room air conditioning),
industrial plants and the like.
[0004] EP-A2-0 901 311 discloses an electric heating means for
motor vehicles. The heating device described comprises a plurality
of heating elements which are combined so as to form a heating
block. The heating block and a control device for controlling the
heating elements are held in a common frame. In this way, the
control device defines a structural unit together with the heating
block held in the frame. The control device comprises a power
electronics with electronic switches which are provided with
cooling bodies. The control device is arranged in such a way that
the main part of an air current to be heated flows through the
heating block and that a boundary portion of said air current is
applied to the control device for the purpose of cooling.
[0005] This known heating device is disadvantageous insofar as the
air current flowing over the control device reduces the total
effectiveness of the heating power. The part of the air current to
be heated which passed the heating block and the part which flowed
past the control device have different output temperatures. The
output temperature of the air current which was applied to the
control device is markedly lower than that of the main current.
This results especially in an inhomogeneous air discharge
temperature. In addition, the heating device will be less effective
when air having a lower temperature flows in.
[0006] It is therefore the object of the present invention to
provide an electric heating device by means of which more effective
heating can be achieved.
[0007] This object is achieved by the features of claim 1.
[0008] According to the present invention, the air to be heated is
not applied to the control device as a whole, but the amount of air
passing through and used for cooling the power electronics can be
controlled through window openings. In this way, an adaptation to
the amount of air passing through the heating block is possible so
that both amounts of air will have substantially the same output
temperature. In this way, the effectiveness of the whole heating
device will not be reduced by an air current which is diverted for
cooling the control electronics.
[0009] According to an advantageous embodiment of the present
invention, means for influencing the air current are provided
within the area between opposed window openings. In this way, the
air current can be conducted such that it is optimally applied to
the cooling elements of the power electronics so that the maximum
possible heating of the cooling air current will be achieved. A
particularly advantageous variant can be accomplished by means of
U-shaped cooling elements in the case of which additional
air-conducting elements can be provided which project between the
legs of the U-shaped cooling elements.
[0010] The cooling air can be heated still further, when it is also
conducted over the components of the control device. For this
purpose, the printed circuit board of the control device is
preferably equipped with components on only one side thereof. A
particularly simple application of air to the components can be
achieved in this way. In addition, such an arrangement of the
components is also particularly advantageous for reasons of
production engineering.
[0011] In accordance with an advantageous embodiment of the present
invention, the printed circuit board is arranged at right angles to
the plane of the frame. This kind of arrangement permits, on the
one hand, a simple application of air to the components. On the
other hand, a small construction depth of the electric heating
device can be achieved in this way.
[0012] The control device can be fixed in a particularly simple
manner when the electric connection lugs of the heating elements,
which project into the box of the lateral bar, are used for such
fixing. For this purpose, spring elements which are complementary
to the connection lugs can be provided on the printed circuit
board. This embodiment permits, with the aid of the same means,
electric contacting, e.g. for conducting the control currents for
the heating elements, as well as mechanical fixing. This has the
effect that the amount of material required, for an electric
heating device according to the present invention and the
investment in the production process of such an electric heating
device will be reduced substantially.
[0013] Further advantageous embodiments of the present invention
are disclosed in the subclaims.
[0014] In the following, the present invention will be described
with reference to the drawings enclosed, in which
[0015] FIG. 1a and 1b show a top view and a side view of an
electric heating device according to the present invention,
[0016] FIG. 2 shows a detail view of the printed circuit board of
the control device, said printed circuit board being equipped with
components,
[0017] FIG. 3 shows a detail view of the box-shaped lateral bar and
of the control device which is adapted to be inserted in said
lateral bar,
[0018] FIG. 4 shows a further detail view of the box-shaped lateral
bar and of the control device which is adapted to be inserted in
said lateral bar.
[0019]
[0020] FIG. 5a, 5b and 5c show detail views of a further embodiment
of the present Invention,
[0021] FIG. 6 shows a simplified perspective detail view of a
realization of a further embodiment of the control device according
to the present invention, and
[0022] FIG. 7a, 7b and 7c show various detail views of the
structural design of the control device according to FIG. 6.
[0023] FIG. 1a shows a side view of the electric heating device 1
according to the present invention. FIG. 1b shows a top view of the
electric heating device 1. The electric heating device 1 includes a
heating block comprising a plurality of heating elements 2 which
are arranged in layers or which are stacked. Each heating element 2
consists of a resistance heating element and of radiators or heat
conducting plates which are arranged adjacent said resistance
heating element. The heating elements used as resistance heating
elements are preferably PTC elements. The heating block comprising
the heating elements 2 is held in a frame. This frame consists of
opposed longitudinal bars 3 and lateral bars 4 and 5 which are
arranged at right angles thereto. The bars of the frame are
produced either from metal or from plastic material.
[0024] Whereas the longitudinal bars 3 have a substantially
symmetrical structural design, the two lateral bars 4 and 5 differ
in the embodiment shown in FIG. 1.
[0025] In contrast to the lateral bar 4, the lateral bar 5 is
implemented as a box which is open on one side thereof. The opening
of this box-shaped lateral bar 5 is located on the lateral-bar side
located opposite the heating elements 2. This box is adapted to
have inserted therein a control device which controls the heat
output of the individual heating elements 2 by controlling the
current supplied to said heating elements 2. The open side of the
box-shaped lateral bar 5 is closed by means of a plug-on or clip-on
cover after insertion of the control circuit.
[0026] After insertion, the printed circuit board 10 of the control
device is preferably arranged at right angles to the plane of the
frame, but a parallel arrangement is possible as well (not
shown).
[0027] The heating device 1 has current supplied thereto via two
connecting pins 8. These connecting pins are implemented such that
they can easily conduct the heating currents demanded. In the
embodiment shown in FIG. 1, the connecting pins 8 project on the
side on which the box-shaped lateral bar 5 is open.
[0028] On the same side a further plug base is provided for
controlling the control device; this plug base is not shown in FIG.
1.
[0029] The lateral bar 5 has window openings 7 on the sides located
in the plane of the frame. These window openings are arranged such
that they, too, are positioned in the air current to be heated.
Cooling elements 6 are arranged between the opposed window openings
7, said cooling elements 6 belonging to the power electronics
components of the control circuit. When the heating device is in
operation, air to be heated flows not only through the heating
block consisting of the heating elements 2 but also through the
window openings.
[0030] The amount of air flowing past the cooling elements 6 can be
determined by selecting the size of the window openings 7.
According to the present invention, the air flow rate is adjusted
such that the differences in temperature between the air flowing
through the heating block and the air flowing past the cooling
bodies 6 are as small as possible. Only if the temperature of the
air flowing through the window openings 7 approaches the
temperature of the air flowing through the heating block as closely
as possible, the heating device will be operated with the highest
possible efficiency.
[0031] FIG. 2 shows a detail view of the control device arranged
within the box-shaped lateral bar. A printed circuit board 10 has
provided thereon a control electronics 12 in addition to the power
electronics components 11. The control electronics 12 determines
the amount of current which is to be delivered by the power
electronics components 11, especially the power transistors, to the
respective associated heating element 2. The amount of current is
supplied to the control device from one of the connecting pins 8
via a conductive rail 13. The output of the power transistor 11 is
fixedly soldered to the printed circuit board 10 and connected to
the spring element 14 which is associated with this transistor.
[0032] The spring elements 14 are arranged on the printed circuit
board in such a way that, when the control device is attached to
the lateral bars 5, they are connected to connection lugs of the
heating elements. Such connection lugs 15 can be seen in FIG. 3 and
4.
[0033] In the embodiment shown, the connection lugs 15 are passed
through the printed circuit board 10 in FIG. 2 and inserted into
the spring elements 14. Such an arrangement permits fast mechanical
fixing of the printed circuit board 10 with the control electronics
in the frame. Simultaneously, electric contacting with the
respective heating elements is effected.
[0034] The printed circuit board is provided with components on
only one side thereof. In accordance with the number of heating
stages, the printed circuit board is provided with power
transistors 11 which are horizontally secured thereto. In the
embodiment shown, three heating stages and, consequently, three
power transistors are provided. Each power transistor 11 is fixedly
soldered to the printed circuit board 10 at the output terminal
thereof.
[0035] A connection lug protrudes beyond the transistor, said
connection lug having a cooling element 6 secured thereto. It will
be advantageous to connect the cooling element 6 to the heating
element in non-conductive manner.
[0036] The cooling element 6 is provided with cooling fins, which
are located in a plane that extends at right angles to the printed
circuit board. In the embodiment shown, the cooling fins are, in
addition, arranged on the non-equipped side of the printed circuit
board. Only one leg of the cooling element 6 projects onto the
equipped side of the printed circuit board and is connected to the
connection lug of the transistor 11 so as to dissipate the heat
produced by said transistor. In the embodiment shown, the
cooling-element leg connected to the transistor 11 projects through
an opening in the printed circuit board 10 onto the equipped side
of the printed circuit board 10. It may, however, also project
beyond the edge of the printed circuit board so that an opening in
said printed circuit board 10 can be dispensed with.
[0037] A corresponding arrangement of the components comprising the
transistor 11, the spring element 14 and the cooling element 6 is
provided for each heating stage on the printed circuit board.
[0038] FIG. 3 shows a detail view of the box-shaped lateral bar 5
and of the control circuit which is adapted to be inserted in said
lateral bar. One side of the lateral bar 5 is connected to the
longitudinal bars 3 and the heating block with the heating elements
2. On the upper surface of the lateral bar 5, the window-shaped
openings 7 can be seen through which the air to be heated
passes.
[0039] Within the box-shaped lateral bar 5 three connection lugs 15
and one connecting pin 8a can be seen. This connecting pin
represents the positive connection for all heating elements 2. This
figure additionally shows a perspective view of the control device
5a which is adapted to be inserted into the box of the lateral bar
5. The control device 5a is inserted into the lateral bar 5 with
the side facing said lateral bar.
[0040] On the side of the control device 5a facing the lateral bar
5, the lower surface of the printed circuit board 10 can be seen.
Three cooling elements 6 project beyond this printed circuit board
10. Each of these cooling elements or cooling plates is associated
with one of the power transistors 11 of a heating stage.
[0041] For each cooling element 6, complementary window openings 7
are provided in the surface of the lateral bar 5. This has the
effect that, when the heating device is in operation, each cooling
element has effectively supplied an air current thereto.
[0042] On the side facing away from the lateral bar, a further
connecting pin 8b can be seen. This connecting pin serves as an
electric ground pole when current is supplied. The connecting pin
8b is connected to the conductive bar 13 which is shown in FIG. 2
and 4 and which supplies the heating current to individual heating
stages. Each individual one of the heating stages draws via its
power transistor 11 up to approx. 40 amperes from the amount of
current supplied via the conductive rail 13.
[0043] FIG. 4 shows a further perspective detail view of the
lateral bar 5 and of the control circuit which is adapted to be
inserted into the box-shaped opening of said lateral bar 5.
[0044] In the upper area of FIG. 4, two of the window openings 7
can be seen on the surface of the lateral bar 5. These window
openings are arranged in such a way that they are positioned above
and below the cooling elements 6 when the control circuit has been
inserted into the lateral bar 5.
[0045] Within the box-shaped opening of the lateral bar 5, the
connection lugs 15 of the heating elements 2 can be seen. One
respective connection lug 15 is provided for each heating
stage.
[0046] In the lower half of FIG. 4, the control circuit which is
adapted to be inserted into the lateral bar 5 is shown. In order to
show the structural design more clearly, only one of the power
transistors 11 is provided with a cooling element 6 in this case.
As for the rest, the structural design of the control circuit
corresponds to the control circuit described in connection with
FIG. 2.
[0047] FIG. 5 shows a further embodiment of the present invention.
FIG. 5a, 5b and 5c show different detail views in which the
embodiment specially differs from the preceding embodiment
described.
[0048] FIG. 5a shows a slightly modified design of the lateral bar
5. The arrangement of the window openings 7 corresponds to the
above-described embodiment. In order to influence the air current
more accurately, walls are provided between the window openings 7
in the lateral bar 5, as far as such a provision of walls is
possible without impeding the insertion of the control circuit in
the lateral bar 5. All the intermediate spaces which are located on
the upper side between the windows and the side facing the heating
element are closed by additional walls 18. In this way, the air is
prevented from flowing around aimlessly when the heating device is
in operation.
[0049] FIG. 5a and 5b show in detail how the air is conducted
between the window openings 7. For accurately conducting the air,
an air-conducting element 17 is inserted into the areas located
between the window openings 7. As can be seen in FIG. 5b, a
Y-shaped spoiler element permits a better flow of air around the
cooling fins of the U-shaped cooling element 6. The respective
cooling fins of the cooling element 6 are arranged adjacent the
window openings 7.
[0050] In FIG. 5b the printed circuit board 10 with the power
transistor 11 is additionally indicated.
[0051] FIG. 5c shows a corresponding structural design of the
cooling element 6. Whereas in the above-described embodiment the
substantially U-shaped cooling element 6 rests with its U-shaped
side perpendicularly on the printed circuit board, the cooling body
6 according to the present embodiment is arranged in such a way
that the U-shape has its lower side arranged parallel to the
printed circuit board 10. Accordingly, the Y-shaped air-conducting
element 17 is arranged in such a way that it projects from the
lateral-bar side facing the heating elements in the direction of
the control device. When a cooling body 6 according to the first
embodiment is used, complementary air-conducting elements can be
arranged on the lateral boundaries between the opposed window
openings 7.
[0052] In the embodiment shown in FIG. 5c, the width b1 of one
cooling fin is approx. 3 mm, whereas the distance b2 between the
cooling fins is slightly smaller, approx. 2.5 mm. The cooling body
is preferably produced from aluminium or copper.
[0053] In FIG. 6 and 7, a further embodiment of a control device
according to the present invention is shown. In this embodiment,
especially the structural design of the power transistors and of
the cooling bodies differs from that of the preceding embodiments.
The cooling bodies 20 according to this embodiment are connected in
a different way to the power transistors. In the preceding
embodiments, the power transistors 11 have cooling vanes formed
thereon, which project beyond the power transistor on one side
thereof. The cooling bodies of the above-described embodiments are
secured to these cooling vanes. The cooling vanes of the power
transistors are soldered to the printed circuit board. In the
embodiment described in the following, the cooling bodies are
connected to the transistor by means of a clipped connection. In
FIG. 6 and 7 it is shown that the cooling bodies 20 of this
embodiment have a special structural design. In order to permit a
clip 21 to engage, the cooling fins of the cooling body 20 have a
non-symmetrical structural design. For this purpose, the preferably
U-shaped cooling body has on one side thereof a smaller number of
fins than is normally the case so as to permit the clip 21 to
engage. The clip preferably engages the power transistor 19 and the
cooling body 20 from outside and secures the cooling body 20 to the
control device and the transistor 19 in this way.
[0054] This embodiment is particularly suitable for SMD-type power
transistors. It is a construction-dependent property of SMD-type
transistors that they are not provided with cooling vanes to which
the cooling body can be secured. In order to be able to connect the
cooling body to the lower surface of the power transistor 19, the
printed circuit board has a hole provided therein and this hole has
preferably a diameter of approx. 7.5 mm.
[0055] Accordingly, the cooling body 20 is provided with pin 20a on
the lower side thereof. In the embodiment shown, this pin projects
in a direction opposite to the direction of the individual cooling
fins. The diameter of the pin 20a is preferably approx. 7 mm.
[0056] The pin 20a formed on the cooling body 20 projects through
the hole in the printed circuit board 10 and contacts the
transistor 19 directly.
[0057] This structural design is shown in FIG. 7a, 7b and 7c in
detail. FIG. 7a shows a top view of the printed circuit board 10
having the power transistor 11 provided thereon. The power
transistor 11 is arranged on the boundary of the printed circuit
board 10 so that the clip 21 used for fixing the cooling body 20
can be fastened easily. The printed circuit board may be provided
with a small indentation at the location at which the clip 21
engages the printed circuit board from above and from below so that
said clip 21 will not necessitate a larger construction depth of
the printed circuit board 10. Preferably, the depth of this
indentation corresponds approximately to the thickness of the clip
21 in this area. The transistor 19 is preferably arranged in such a
way that connection contacts 22 point towards the opposite edge of
the printed circuit board 10.
[0058] FIG. 7b shows a side view. FIG. 7c shows a sectional view
along the sectional line A-A in FIG. 7b. FIG. 7c shows that the
cooling body 20 and the spring 21 are geometrically adapted to one
another in such a way that correctly positioned fixing with an
optimum pressure application point is guaranteed.
* * * * *