The invention relates to a heat dissipater of an electric heating device intended to be passed through by a flow of air to be heated. The invention applies more particularly to the heating and/or air conditioning appliances for motor vehicles. The present invention relates also to the method for assembling an electric heating device.
Usually, the heating of the air intended to heat the interior of a motor vehicle, and for the defogging and de-icing is ensured by the passage of a flow of air through a heat exchanger, more specifically by a heat exchange between the flow of air and a liquid, generally the engine coolant.
However, this heating mode can prove unsuitable or inadequate to guarantee a rapid and effective heating of the car interior and can thus hamper the thermal comfort in the interior of the vehicle. Because of this, one way of improving the comfort for the passengers is to rapidly heat the air in the car interior, above all during the winter period.
In order to meet these comfort demands, one known solution consists in allocating an electric heating device, also called electric radiator, to the heat exchanger.
This electric heating device comprises electric heating modules positioned so as to be exposed directly to the air passing through the electric heating device to produce an almost immediate heat top-up.
According to one known solution, the heating modules are produced in the form of heating bars; a heating bar comprising resistive elements for example with positive temperature coefficient (PTC), such as PTC stones, heat dissipaters and electrodes. A heating module or heating bar is, for example, known which comprises two electrodes which extend longitudinally, each gripping a heat dissipater formed for example by a folded or corrugated metal tape coming to bear against resistive elements, such as PTC stones.
The electrodes make it possible to distribute the electrical current, supplied by an electrical power source, to the resistive elements.
The function of the heat dissipater produced by the corrugated tape consists in exchanging, with the flow of air, the heat produced by the PTC effect by the resistive elements, so as to heat the flow of air passing through the heat dissipater.
The heating device generally comprises a frame having housings for receiving the heating modules comprising the resistive elements, the heat dissipaters and the electrodes.
Such heating modules have a major drawback: because of their structure, these heating modules are costly. In effect, they comprise at least three elements: the resistive element, the electrode and the heat dissipater, as well as a frame supporting all these elements. These heating modules therefore require a number of components or materials, which means a significant cost.
Furthermore, assembling the elements of the heating modules and assembling the heating modules in the frame can prove complex.
The aim of the invention is therefore to mitigate these drawbacks of the prior art by proposing an electric heating device that is simplified by reducing the number of elements in order to lower the cost of manufacture of the electric radiator.
Another object of the invention is to make it possible to simplify, even automate, the method for assembling such an electric heating device or electric radiator.
The present invention provides a solution via a heat dissipater of a heating module for an electric heating device for a flow of air, said heating module comprising at least one heating element and said heat dissipater being configured to be passed through by the flow of air and to transmit the heat from the heating element to the flow of air to be heated, characterized in that the heat dissipater is a unitary block having at least one housing for receiving at least one heating element, the housing having at least one opening formed on a face of said dissipater intended to be in contact with the flow of air.
Such a heat dissipater forming a unitary block can have a support function for the heating elements. A single heat dissipater block makes it possible to transfer the heat produced by the heating elements to the flow of air to be heated. The same heat dissipater ensures this heat dissipation function for all the heating elements, and no longer one heat dissipater for each row of heating elements as in certain of the prior art solutions.
Nor is it necessary any longer to provide a support for the heating elements and heat dissipaters.
Furthermore, the design of the heating module is simplified. In particular, the heating elements, such as resistive elements of positive temperature coefficient type, and the associated electrodes, are directly received in a housing of the heat dissipater. There is no need to provide, for each heating structure, a heat dissipater gripped by the electrodes and coming to bear against the resistive elements, with everything having to be inserted into a housing of a support frame.
Said heat dissipater can further comprise one or more of the following features, taken separately or in combination:
The invention also relates to a heating module of an electric heating device for a heating and/or air conditioning apparatus for a motor vehicle, comprising at least one heating element and a heat dissipater configured to be passed through by a flow of air and to transmit the heat from the heating element to the flow of air to be heated, characterized in that the heat dissipater is a unitary block having at least one reception housing for at least one heating element and forming a support for said at least one heating element, the housing having at least one opening formed on a face of said dissipater intended to be in contact with the flow of air.
Said heating module can further comprise one or more of the following features, taken separately or in combination:
The invention also relates to a method for assembling a heating module as defined previously, characterized in that it comprises the following steps:
Said method can further comprise one or more of the following features, taken separately or in combination:
Other features and advantages of the invention will become more clearly apparent on reading the following description, given as an illustrative and nonlimiting example, and the attached drawings in which:
a is a transverse cross-sectional view of a heat dissipater of the heating module represented in
b is a transverse cross-sectional view of the heat dissipater of
c is a transverse cross-sectional view of the heat dissipater of
d is a transverse cross-sectional view of the heat dissipater of
e is a view of
f is a transverse cross-sectional view of the heat dissipater of
a is a schematic front view representing a heat dissipater of the heating module of
b is a schematic view of the heating module according to the third embodiment during a step of insertion of heating structures into housings of the heat dissipater of
In these figures, the elements that are identical bear the same references.
The elements of
The elements of
In a heating and/or air conditioning apparatus of a motor vehicle, the heating of the air can be ensured by a heat exchanger, for example using the engine coolant as heat transfer liquid and/or by an electric heating device 1, otherwise called electric radiator, schematically and partially represented in
Such an electric heating device 1 is arranged in such a way as to be passed through by the flow of air to be heated.
The heating device 1 comprises a heating module 3 or several heating modules 3, all identical or different. The electric heating device 1 of the present application, passed through by a flow of air, therefore comprises at least one heating module 3 according to one of the embodiments described hereinbelow.
Whatever the embodiment described hereinbelow, the heating module 3 comprises at least one heating element 5 and a heat dissipater 7, 107, 207.
More specifically, a heating module 3 can comprise at least one resistive element 5 of positive temperature coefficient (PTC) type. The resistive elements are, for example, produced in the form of PTC stones. The resistive element 5 can be of parallelepipedal form. Through its form, this resistive element 5 comprises two opposite large end faces 5a, 5b.
Also, the heating module 3 comprises a common heat dissipater 7, 107, 207 for all the resistive elements 5. The heat dissipater 7, 107, 207 makes it possible to transmit the heat from the heating elements 5 to the flow of air to be heated which passes through the heating module 3.
This heat dissipater 7, 107, 207 is made of a thermally conductive metal material. Furthermore, the material is electrically conductive. This material can be aluminum.
Furthermore, the heat dissipater 7, 107, 207 forms a support for the heating element or elements 5, and all the elements of the heating module 3 as will be detailed hereinbelow. For this, the heat dissipater 7, 107, 207 is produced in the form of a unitary block which has at least one reception housing 9, 209 for at least one heating element 5.
According to a first embodiment illustrated in
The heat dissipater 7 is, for example, produced in the form of a deformed support plate in which the deformations form at least one reception housing for the resistive elements, for example by stamping or casting. The support plate formed by the heat dissipater 7 has a generally substantially parallelepipedal form. The length L and the width l are schematically defined in
The flow of air to be heated passes through the heating module 3 in a direction substantially at right angles to the general plane P defined by the heat dissipater 7. This heat dissipater 7 has two opposite air inlet and outlet faces, in the direction of flow of the flow of air to be heated.
The heat dissipater 7 is suitable for receiving at least one heating element 5, here a resistive element in PTC stone 5 form. The heat dissipater 7 has, to this end, at least one reception housing 9 for one or more resistive elements 5 and at least one heat dissipation area 11 for dissipating the heat produced by the resistive elements 5 to the flow of air passing through the heat dissipater 7.
According to the example illustrated, the dissipater 7 is suitable for receiving three resistive elements 5 in a reception housing 9 and has three reception housings 9. Each housing 9 is therefore dimensioned in such a way as to receive at least one entire resistive element 5, here three entire resistive elements 5.
The resistive elements 5 are arranged in the housings 9 so as to be directly exposed to the flow of air passing through the heat dissipater 7.
The housings 9 have at least one opening formed on a face of the dissipater 7, intended to be in contact with the flow of air passing through the dissipater 7.
In particular, the opening is formed on the airflow outlet face of the dissipater 7.
The housing 9 is therefore semi-open which makes it possible to simplify the assembly of the elements of the heating module 3 on the dissipater 7, as will be described hereinbelow.
A reception housing 9 is, according to the first embodiment illustrated, produced with a substantially “U”-shaped transverse section, as can be better seen in
Furthermore, a housing 9 has a solid surface, that is to say without any holes, so that it is not passed through by the flow of air to be heated.
The housing 9 is provided for the fixing of one or more resistive elements 5. The fixing can, for example, be done by bonding, using a bonding agent 10 (see
The resistive element or elements 5 are arranged in electrical and thermal contact with the heat dissipater 7. The latter is linked to the ground. More specifically, a resistive element 5 is arranged in a housing 9 associated with a first end face 5a in electrical and thermal contact with the heat dissipater 7.
Moreover, the heat dissipater 7 forms a support for the different elements of the heating module 3.
Thus, according to this first embodiment, a reception housing 9 is also suitable for receiving an electrode 12. This electrode 12 is produced in the form of a plate extending longitudinally in the lengthwise L direction of the heat dissipater 7.
At one end of the electrode 12, the electrode plate has a terminal 12a for connecting to an electrical power source (not represented). The connection terminal 12a forms a protuberance relative to the heat dissipater 7, in the lengthwise L direction.
The electrode 12 is arranged on the resistive element or elements 5 received in the associated reception housing 9. According to the example illustrated, an electrode 12 is arranged on three PTC stones 5 in an associated housing 9.
As said previously, a resistive element 5 has two opposite large faces 5a, 5b, with one large face 5a in electrical and thermal contact with the heat dissipater 7, and the other large face 5b of a resistive element 5 in electrical contact with the electrode plate 12. Thus, a resistive element 5 is arranged between the heat dissipater 7 on the one hand, and an associated electrode plate 12 on the other.
Finally, an additional layer 13 can be provided, notably a deposition of silicone, on the elements received in a reception housing 9 of the heat dissipater 7. This additional layer 13 is provided to maintain contact between the electrode plate 12 and the resistive element or elements 5 received in the associated housing 9 and to protect these elements. A certain reliability and robustness of the heating module 3 is thus guaranteed. This additional layer 13 is a layer of electrical insulation, such as a layer of silicone. The electrically insulating silicone is thermally conductive, so as to participate in the heat transfer between the heating elements 5 and the flow of air passing through the heating module 3.
As mentioned previously, the heat dissipater 7 also comprises at least one heat dissipation area 11.
The heat dissipation area 11 is intended to exchange heat with the flow of air passing through the heating module 3 and consequently passing through the heat dissipater 7. The phrase “exchange heat with the flow of air” should be understood to mean the fact that the flow of air passes right through the heat dissipation area 11 in a direction substantially at right angles to the plane P defined by the heat dissipater 7 and thus increases its temperature on contacting this heat dissipation area 11.
This heat dissipation area 11 has a plurality of louvers 15 that can be better seen in
These louvers 15 are, for example, produced by cutting and folding.
The louvers 15 have a substantially “U”-shaped transverse section and each comprise a substantially rectangular large face 15a defining the length of the louver 15 and two small lateral faces 15b, 15c to a planar wall 17 of the heat dissipation area 11.
The louvers 15 are contained in a plane substantially parallel to the plane P. Louvers 15 are notably provided that are spaced apart over the entire heat dissipation area 11 in the lengthwise L direction of the heat dissipater 7. In other words, the louvers 15 follow one another in the lengthwise L direction of the heat dissipater 7.
A heat dissipation area 11 is therefore distinct from the reception housing 9.
“Distinct” should be understood to mean the fact that a reception housing 9 and a heat dissipation area 11 are of different structures. In effect, a housing 9 has a solid surface without holes and is thus not passed through by the flow of air to be heated, whereas the heat dissipation area 11 is holed and is thus passed right through by the flow of air to be heated.
The distinction between a housing 9 and a heat dissipation area 11 stands also from the fact of their different functions. In effect, a housing 9 is the site for fixing one or more resistive elements 5 onto the heat dissipater 7 and makes it possible to conduct the heat produced by the resistive elements 5 to the heat dissipation area 11, whereas, for its part, the heat dissipation area 11 makes it possible to dissipate the heat produced by the resistive elements 5 to the flow of air passing through the heat dissipation area 11.
Moreover, the heat dissipater 7 can comprise a plurality of housings 9 and dissipating areas 11. More specifically, the heat dissipater 7 can comprise an alternation of housings 9 and of dissipating areas 11. According to the example illustrated, the heat dissipater 7 comprises three housings 9 and four dissipating areas 11 arranged alternately. This alternation is produced widthwise l on the heat dissipater 7. In this way, a housing 9 is adjacent to two heat dissipation areas 11 intended to exchange heat with a flow of air passing through the heat dissipater 7. The housings 9 and the heat dissipation areas 11 of the heat dissipater 7 are contained in the same plane P.
Such a dissipater 7 forming a support for the elements of the heating module 3 therefore forms a unitary block. The housings 9 and the heat dissipation areas 11 are secured to the heat dissipater 7. The assembly of the elements of the heating module 3: the heat dissipater 7, the resistive elements 5, the electrodes 12, forms a heating block.
A method for assembling a heating module 3 as described above is described with reference to
In a first step (
More specifically, according to the first embodiment, the heat dissipater 7 is produced in a single piece from a metal material. Thus, the housings 9 and the heat dissipation areas 11 are produced in a single piece with the heat dissipater 7. A single-piece part is thus available, produced by simple stamping or by casting.
A cutting step can make it possible to cut the material to the desired dimensions. Then, it is possible to form, for example by stamping or casting, at least one semi-open reception housing 9, for example of substantially “U”-shaped transverse section, and at least one heat dissipation area 11 suitable for being passed right through by the flow of air to be heated. Louvers 15 can, for example, be produced by cutting and folding in the heat dissipation area or areas 11.
In a second step (
In a third step (
In a fourth step (
The method can then comprise a pressing step (
The method can also comprise a step of deposition of an additional layer 13 for maintaining contact between the electrodes 12 and the associated resistive elements 5 in a reception housing 9 of the heat dissipater 7. This additional layer 13 is an electrically insulating layer, such as a layer of thermally conductive silicone. This electrically insulating layer also ensures that the elements received in the housing 9 are mechanically secured while allowing the heat dissipation to be controlled.
Finally, a step of heating of the duly assembled assembly can be provided, for example by passing through an oven.
Thus, all the elements of the duly obtained heating module 3 are finally fixed to one another, forming a heating block.
In effect, according to this second embodiment, the heat dissipating block 107 comprises a support plate 119, for example produced in aluminum, and dissipation fins 121, for example produced in aluminum. The assembly can be fixed by bonding or brazing, thus forming a unitary block.
The dissipation fins 121 are arranged in the heat dissipation areas 111 of the heat dissipater 107.
In a manner similar to the first embodiment, the reception housings 109 are produced with a “U”-shaped transverse section and extend in the lengthwise L direction of the heat dissipater 107.
The resistive elements 5, the electrodes 12 and a thermally conducting and mechanically securing electrically insulating layer 13 are identical to the first embodiment.
Similarly, the steps of the assembly method are substantially the same as for the first embodiment.
The difference lies in the phase of obtaining of the heat dissipating block 107 comprising dissipation fins 121.
The dissipation fins 121 can be produced in a single piece with the heat dissipater 107 and the housings 109, for example by casting.
As a variant, the dissipation fins 121 can be brazed or even bonded to the housings 109 to form a heat dissipater 107 in unitary block form.
Finally, a third embodiment is represented in
According to this third embodiment, the heat dissipating block 207 has a support plate 219 comprising housings 209 and dissipation fins 221.
This third embodiment differs from the first and second embodiments by the fact that the housings 209 are substantially tubular and have a substantially rectangular transverse section as represented in
Furthermore, according to this third embodiment, the heating structures 223 are arranged in the associated housings 209 of the heat dissipater 207.
The form of the housings 209 complements the form of the heating structures 223.
Referring to
In this case, the resistive elements 5 are electrically insulated from the heat dissipater 207 using an insulating jacket 225. This insulating jacket 255 surrounds the heating elements 5 and the associated electrodes 212 and 212′ to insulate them from the heat dissipater 207. The insulating jacket 255 is, for example, produced in Kapton.
Referring to
In a first step (
More specifically, a support plate 219 is produced that has partially open, substantially tubular housings 209, and heat dissipation areas 211 comprising dissipation fins 221. One and the same material, for example aluminum, is used for the support plate 219 and the fins 221. The assembly can be assembled by bonding or brazing, or, in a variant, the fins 221 can be produced in the same mold as the support plate 219 and the housings 209.
In a second step (
In the preliminary step of assembly of a heating structure 223, as illustrated in
When a heating structure 223 is inserted into an associated housing 209 of the heat dissipater 207, from the left in
A heating block is thus obtained in which the elements of the heating module 3: the resistive elements 5, the electrodes 212, 212′, and the insulating jacket 225, are borne by the heat dissipater 207.
It will therefore be understood that a heat dissipater 7, 107, 207 according to any of the embodiments previously described, forms a unitary block advantageously produced in one and the same material and preferably in a single piece, and serves as support for all of the elements of the heating module 3, notably for the resistive elements 5 and the associated electrodes 12, 212, 212′.
The number of elements of the heating module is thus reduced, because the heat dissipater 7, 107, 207 combines the functions:
The method for assembling a heating module 3 is thus simplified because it requires fewer steps and can be easily automated.
Number | Date | Country | Kind |
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1259983 | Oct 2012 | FR | national |
Filing Document | Filing Date | Country | Kind |
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PCT/EP2013/071777 | 10/17/2013 | WO | 00 |