WO2020065169A1

WO2020065169A1 - Electric heating device

Info

Publication number: WO2020065169A1
Application number: PCT/FR2019/052112
Authority: WO
Inventors: Yann COUAPEL; Erwan Gogmos
Original assignee: Valeo Systemes Thermiques
Priority date: 2018-09-28
Filing date: 2019-09-12
Publication date: 2020-04-02
Also published as: FR3086736A1

Abstract

Electric heating device (1) for heating an air through-flow, composed of a frame (2) incorporating at least one heating element (4), the at least one heating element (4) running longitudinally within the frame (2), and an electronic control interface housing (6) including a base (26), which base is configured to house electronic control components for controlling the at least one heating element (4), and a cover (34), the cover (34) including a peripheral portion (36) for attachment to the base (26) and a central portion (40) for covering the electronic components of the electronic control interface housing (6), the cover (34) having a substantially planar surface that lies mainly in a first plane (AB) and at least one local stiffening element (44) forming, in the central portion (40), a contact surface for a tool on the outside of the electronic control interface housing (6), said contact surface running in a longitudinally offset manner with respect to the first plane (AB) of the cover (34).

Description

ELECTRIC HEATING DEVICE

The field of the present invention is that of motor vehicle heating. It relates to electric heating devices intended to be mounted in a ventilation, heating and / or air conditioning installation of a motor vehicle.

More particularly, the invention relates to an electric heating device comprising heating modules by diffusion of heat under the effect of an electric potential, that is to say resistive heating elements, for example resistors with temperature coefficient positive (CTP), which allow heat to be generated quickly in vehicles by means of a given power supply.

The implementation of such electric heating devices is known for heating an air flow passing in particular through a duct of a ventilation, heating and / or air conditioning installation of a motor vehicle. In this context, the electric heating devices, or electric radiators, comprise an openwork frame configured to carry heating modules by diffusion of heat under the effect of an electric potential so that these heating modules are in contact with the air passing through the frame. The frame contains compartments for receiving at least one heating module which extends longitudinally and which can be formed of a tube inside which are housed electrodes which surround the resistive heating elements. The electrodes are extended outside the tube by connection terminals which extend to connection terminals, themselves connected to a printed circuit board. The connection terminals, the printed circuit board and the other electronic components necessary for the operation of the electric heating device are integrated in an electronic interface box which includes a base receiving these components and a cover which overlaps to protect them. .

The evolution of technologies and thermal needs of motor vehicles allow the implementation of electric heating devices supplied with high voltage, so as to deliver by the resistive elements a thermal power capable of heating the air passing through the installation ventilation, heating and / or air conditioning without the need to add an additional heat exchanger. These high-voltage devices require the provision of larger and larger electronic components, and this is accompanied by the need for large electronic interface boxes to house these components. The fact of having large electronic interface boxes implies having covers having a large surface area, which are conducive to deformation.

A problem with such a device therefore lies in the rigidity of the cover which, due to its high surface area, can easily deform under external mechanical stresses, whether these manifest themselves during the running of the vehicle and the vibrations which result therefrom, or else during the assembly of the electric heating device with the connection and connection terminals fitted into each other.

The present invention falls within this context and it relates to an electric heating device for heating a flow of air passing through, composed of a frame incorporating at least one heating element, the at least one heating element s extending longitudinally in the frame, and of an electronic interface box comprising a base, configured to house electronic components controlling the at least one heating element, and a cover, the cover comprising a peripheral portion for fixing to the base and a central part for covering the electronic components of the housing. According to the invention, the cover has a substantially flat surface extending mainly along a first plane and at least one local stiffening element forming in the central part a support surface for a tool outside the housing, said support surface. extending in longitudinal offset from the foreground of the cover.

The local stiffening element makes it possible to break the flatness of the flat surface of the cover and thus makes it possible to reduce the possibility of deformation of the cover of the housing by means of mechanical stresses exerted on the electric heating device. These mechanical stresses can in particular be exerted during the assembly of the device, with the frame and the heating elements which it participates in housing which are brought back opposite the electronic interface box to connect the electrodes of the heating elements to the circuit. power supply arranged in the housing. During this assembly, a tool external to the housing is used to form a counter support during the connection of the electrodes, while being placed in abutment against the external surface of the cover, that is to say the face turned away from the base of the housing and therefore away from the frame. The presence of this tool allows fitting of the electrode terminals into the terminals of the electronic components, ensuring that the housing remains in place. And the local stiffening element produced according to the invention on the cover makes it possible to ensure that this cover does not deform or very little. Furthermore, it is notable that this local stiffening element is capable of forming a zone for receiving the tool, making it possible to have the latter in an optimized position for producing the counter support.

According to different features of the invention, taken alone or in combination, provision may be made for: - the frame intended to receive the at least one heating element has substantially the shape of a rectangular parallelepiped;

- the frame intended to receive the at least one heating element is partially perforated so as to be traversed by an air flow intended to be in contact with the at least one heating element; - The stiffening element is obtained by deformation of the cover; in particular, the stiffening element is produced by stamping the cover;

- The stiffening element obtained by deformation of the cover may have the shape of a tank projecting from the flat surface of the cover towards the inside of the housing, the tank comprising a bottom which forms the bearing surface for the tools outside the housing; - The stiffening element obtained by deformation of the cover may have the form of a boss projecting from the flat surface of the cover towards the outside of the housing, the boss comprising a top which forms the bearing surface for the tools outside the housing;

According to a characteristic of the invention, at least two heating elements are stacked in series along a first dimension of the frame, and the stiffening element extends in a direction corresponding to said first dimension of the frame over the same length as that of the stack of at least two heating elements.

According to a characteristic of the invention, the bottom of the tank forming the element of stiffening obtained by deformation of the cover has an inner face opposite the electronic components housed in the electronic interface box and an opposite outer face, the inner face having at least one stud which protrudes from this inner face and which extends towards inside the housing. In this context, the electronic interface may include a printed circuit board having an upper face and a lower face, so that the upper face is the face of the printed circuit board facing the cover and that the lower face is the face of the printed circuit board facing the frame, the at least one stud being configured to provide a bearing surface on the upper face of the printed circuit board during assembly of the frame and the heating elements on the housing . This characteristic can in particular be implemented by an arrangement of the housing before assembly with the frame in which the stud or studs are in direct contact with the printed circuit board.

According to a characteristic of the invention, at least one stud, of cylindrical shape, has a height substantially equal to its diameter, the height being the dimension defined as that of the projection perpendicular to the bottom wall of the tank.

According to a characteristic of the invention, several studs extend projecting from the cover towards the inside of the housing, all of these studs being arranged on the inner face of the stiffening element. According to a characteristic of the invention, reinforcing ribs extend in or on the stiffening element, turned towards the outside of the housing.

According to a characteristic of the invention, the frame has a plurality of heating elements arranged in transverse series in the frame, each of the heating elements having a proximal end and a distal end, each of the distal ends of each of the heating elements comprising two terminals. connection able to be inserted in connection terminals integral with the printed circuit board housed in the electronic interface box, all the connection terminals forming a first on one side of the printed circuit board row and a second row parallel and offset from each other, the plurality of studs also forming two parallel rows and offset from each other so that in an assembled position of the housing with the frame, the connection terminals and the pads are arranged alternately.

Advantageously, the connection terminal has an insertion slot making it possible to house a connection terminal. The connection terminal has a rectangular section of complementary shape with the shape of the slot of the connection terminal.

According to a characteristic of the invention, the local stiffening element is a set of ribs turned towards the outside of the electrical control interface box. It is understood that the shape and size of the ribs are intended to form, as described above, a support surface for the tools external to the housing.

The invention also relates to a heating, ventilation and air conditioning installation of a motor vehicle, comprising an electric heating device as described above, and in particular a heating device supplied with high voltage, for example of the order of at least 200V. Other characteristics, details and advantages of the invention will emerge more clearly on reading the description given below by way of indication in relation to the drawings in which:

- Figure 1 is a general perspective view of an electric heating device according to a first embodiment of the invention, making visible in particular a frame, capable of accommodating heating elements, and an electronic interface box , the housing being composed of a base and a cover;

- Figure 2 is a perspective view of an outer face of a cover capable of fitting a heating device according to a second embodiment of the invention; - Figure 3 is a perspective view of an outer face of a cover capable of fitting a heating device according to a third embodiment of the invention;

- Figure 4 is a sectional view showing a heating element and its associated electrodes, as well as the connection and connection terminals allowing connecting the electrodes to a printed circuit board, the heating device here consisting of an alternative embodiment in which studs are produced on an inner surface of the cover;

- Figure 5 is a perspective view of the cover of Figure 4, showing its inner face and the plurality of studs;

- Figure 6 is a front view of an alternative embodiment of the cover of the electronic interface box, in which reinforcing ribs are arranged in the stiffening element obtained by deformation of the cover;

- And Figure 7 is a cross-sectional view of the cover of Figure 6. It should first be noted that the figures show the invention in detail to implement the invention, said figures can of course be used to better define the invention if necessary.

In the following description, the longitudinal direction is defined as the direction corresponding to the main axis of the electric heating device and the heating elements which compose it, and the direction corresponding to the direction of insertion of the heating elements into the device. of heating. The vertical and transverse directions are defined as the directions corresponding to directions perpendicular to the longitudinal direction, the transverse direction corresponding to the direction of stacking of the heating elements one next to the other and the vertical direction corresponding to the direction of flow. air through the electric heater.

The directions mentioned above are also visible in an orthonormal reference frame LVT represented in the figures.

Referring first to FIG. 1, an electrical heating device 1 is seen comprising a frame 2, at least one heating element 4 and an electronic interface box 6.

The electric heating device 1 is configured to be integrated within a housing of a heating, ventilation and / or air conditioning installation. He understands in particular the frame 2 where the heating element or elements 4 are arranged which make it possible to heat the air passing through the frame of the electric heating device in a vertical direction and more particularly in a direction illustrated in FIG. 1 by an arrow F, and the box 6 contains all of the electronic components which make it possible both to control the operation and to supply the heating device 1 electrically.

The frame 2 is here produced in a single piece, in one piece, and it has the shape of a rectangular parallelepiped extending mainly along a longitudinal axis. More particularly, the frame 2 comprises a bottom wall 8 which extends opposite the housing 6 when the electric heating device 1 is assembled. At each of the transverse ends of the bottom wall 8 is positioned respectively a first side wall 10 and a second side wall 12, extending perpendicular to the bottom wall 8. The first side wall 10 and the second side wall 12, arranged facing each other, participate in delimiting transversely the housing formed by the frame of the electric heating device 1. The assembly formed by the bottom wall 8, the first side wall 10 and the second side wall 12 has the shape of a U, where the bottom wall 8 forms the base of the U, the box 6 closing the opening of the U during assembly of the electric heating device 1.

The U-shape of the frame 2 makes it possible to generate perforated faces which extend perpendicular to the vertical direction and therefore to the passage of air passing through the electric heating device.

The frame 2 has a plurality of longitudinal bars 14 which extend across these perforated faces, parallel to the first side wall 10 and the second side wall 12. The plurality of longitudinal bars 14 is arranged in series in the previously transverse direction mentioned.

The bottom wall 8, the first side wall 10, the second side wall 12 and the plurality of longitudinal bars 14 participate in forming at least one housing in which is positioned at least one heating element 4 as it has been presented below. -above.

The at least one heating element 4 comprises resistive elements electrically supplied so that they heat and thus participate in heating the flow of air passing through. the electric heating device in the direction F. Thus, the at least one heating element is electrically connected to an electrical network of the vehicle via the electronic interface box 6. Details on the structure of the heating elements will be given below with reference to FIG. 4.

The at least one heating element 4 extends along a longitudinal axis of the electric heating device 1, parallel to the first side wall 10 and the second side wall 12. It has a proximal end 18, defined thus in that it is disposed near the bottom wall 8 of the frame 2 when the electric heating device is assembled, and a distal end 20, defined thus in that it is arranged at a distance from the bottom wall 8 of the frame 2.

It should be understood that the characteristics which have been described and which will be described subsequently for a heating element 4 apply for each of the heating elements 4 capable of being housed in frame 2 of the electric heating device 1.

The housing 6 comprises a base 26 and a cover 34. The base 26 is configured to house electronic components and the cover 34 is arranged in overlap with the base 26 in order to protect the electronic components.

The base 26 has an internal face, not visible in FIG. 1 and facing the interior of the housing 6 and towards the electronic components, and an external face 23.

The base 26 comprises a set of fixing members 28 making it possible to fix the electric heating device 1 in a compartment of the housing of the heating, ventilation and / or air conditioning installation provided for this purpose. The set of fastening members 28 is arranged projecting from the external face 23 of the base 26.

The base 26 has a proximal longitudinal portion 25 close to the frame 2, capable of cooperating with the frame to allow assembly of one with the other, and a distal longitudinal portion 27 remote from the frame 2, on which is fixed the hood.

Also, the base 26 has a T-shape comprising a first part 29 and a second part 31 larger than the first part 29. The second part 31 is located in the longitudinal extension of the frame 2 and the first part 29 is offset vertically compared to the second part 31. On the first part 29 of the base 26 is positioned an electrical connection socket 32. The electrical connection socket 32 makes it possible to supply electrical current, particularly at high voltage, to the electronic components of the housing 6 and the resistive elements of each heating elements. The base 26 comprises on its external face 23 and on its distal longitudinal part

27 at least one lug 30. The at least one lug 30 enables the cover 34 to be fixed to the base 26. This fixing means will be detailed later in the detailed description.

The cover 34 also has a T shape complementary to the shape of the base 26. More particularly, it comprises a first portion 48, having a shape and dimensions equivalent to those of the first part 29 of the base 26, and a second portion 50, having a shape and dimensions equivalent to those of the second part 31 of the base 26.

The cover 34 extends mainly in a plane AB, comprising the transverse axis A and the vertical axis B Thus the cover 34 takes the form of a plate which comes to cover the base 26, in particular to protect the components electronics housed in the base.

The cover 34 comprises a peripheral portion 36 and a central portion 40. The peripheral portion 36 has at least one tongue 38 which extends perpendicular to the plane AB in which the cover mainly extends and whose function is to fix the cover 34 to the base 26 by complementarity with the at least one lug 30. It is understood that the lugs 30 and the tongues 38 cooperate to form latching means by elastic deformation.

On the central part 40 and in the first portion 48 is positioned an air opening 42. The air opening 42 makes it possible to prevent all of the electronic components integrated in the housing 6 from overheating.

The central part 40 of the cover according to the invention comprises a stiffening element 44 and more precisely in the second portion 50 of the cover 34, so as to be in the longitudinal extension of the heating elements 4 arranged in the frame when the heating device electric is assembled. The stiffening element 44 extends mainly along the transverse axis of the electric heating device 1, its dimension along this transverse axis being equal to the dimension of the transverse stack of the heating elements 4 inside the frame. In others, the stiffening element has a transverse dimension such that the longitudinal projection of all the heating elements is located within the extent of the stiffening element.

In the first embodiment illustrated in FIG. 1, the stiffening element 44 is produced by deformation, in particular by stamping, of the central part 40 of the cover, this deformation being carried out towards the inside of the housing 6. In this way , the stiffening element has the form of a tank 440 seen from outside the housing. This tank 440 comprises a bottom 46 which extends in longitudinal offset with respect to the plane AB in which the cover 34 mainly extends, the bottom 46 being disposed more inside the housing 6 than the rest of the central part 40 of the hood.

The wall forming the bottom 46 is defined in that it has an inner face 52 which faces the inside of the case 6 and an outer face 54 which faces the outside of the case 6.

The advantage of such an embodiment of the invention according to FIG. 1 is to avoid the cover 34 having a flat surface over its entire transverse dimension and thus to avoid a risk of deformation of the cover 34 during vibrations or stresses which may result from the vehicle running or from the assembly operation of the electric heating device 1.

During this assembly operation, a tool 100 (visible in FIG. 4) forms a support against contact with the outside face of the cover 34, the stiffening element 44 corresponding to a support surface of the tool. 100 against the cover 34. The assembly operation will be described in more detail with reference to FIG. 4 making visible the cooperation of the terminals for connecting the heating elements and their electrodes to the electronic interface box.

Without limiting the invention, FIG. 1 also shows a heat sink 16, positioned on the perforated face of the frame through which the air flow is likely to enter in the direction L. The heat sink 16 can especially allow the calories released by the electronic components used to generate the control and the electrical supply of at least one heating element 4 to be removed.

FIG. 2 shows a cover 34 of a heating device according to a second embodiment, said cover 34 differing from what has been previously described by the shape of the stiffening element 44.

The cover 34 is, as before, capable of being fixed on the base to ensure the coverage of the electronic components logged in the base of the electronic interface box. In this second embodiment, the stiffening element 44 has the shape of a rib 442 at H. The term “rib 442 at H” is understood to mean a configuration in which two main ribs extend transversely in the central part 40 and in which a rib extends vertically to link the two main ribs to each other.

The stiffening element 44 of the embodiment of FIG. 2 is thus configured to form a projection from the main plane in which the flat surface of the cover 34 extends, but it should be noted that, unlike the tank 440 of Figure 1, the rib 442 is facing outward, opposite the housing.

As for what has been described previously, with the shape of the stiffening element having the shape of a tank, the advantage of such a rib 442 is to avoid the cover 34 from presenting a flat surface over its entire transverse dimension and thus to limit the deformation of the cover following vibrations or mechanical stresses which may appear during the use of the vehicle but also during the mounting of the electrodes in their connection terminals 68 fixed to the housing 6, a tool 100 coming to put pressure on the external face of the cover 34.

The advantage of the rib is also, in this context, to delimit a support area of the tool against the cover 34 and to allow the obtaining of punctual contacts between the cover and the tool, the support area advantageously being arranged outside the base so that the use of a robot carrying the tool does not present a risk of coming into contact with the electronic interface box. Furthermore, although the stiffening element 44 of FIG. 2 is different in its ribbed shape, it retains the same dimensional dimensional characteristics mentioned above in FIG. 1. More particularly, the main longitudinal ribs extend over one dimension transverse equal to the transverse stacking dimension of the heating elements.

FIG. 3 represents a third embodiment of the invention according to which the cover 34 differs from the above in that the stiffening element 44 has the form of a boss 444. By boss is meant a deformation of the cover 34 forming a projection towards the outside of the housing 6. The characteristics relating to the transverse dimension of the tank of the first embodiment illustrated in FIG. 1 apply identically to the stiffening element 44 of FIG. 3 under boss form.

Again, the advantage of such a boss 444 is to avoid the cover 34 having a flat surface over its entire transverse dimension and thus to limit the deformation of the cover due to vibrations or mechanical stresses which may appear during use. of the vehicle but also during the mounting of the electrodes in their connection terminals 68 fixed to the housing 6, a tool 100 coming to press on the external face of the cover 34.

And it is deduced from what has been described in relation to the covers illustrated in FIGS. 1 and 2, that the production of the stiffening element in the form of a boss makes it possible to have an imprint allowing a form cooperation with the tool forming against support against the cover during assembly, for the correct positioning of the tool in the longitudinal extension of the heating elements, and that this form cooperation advantageously takes place at a distance from the base of the housing to facilitate handling of this tool. FIG. 4 presents a view in longitudinal section of a part of the electric heating device 1 once it has been assembled, with the frame and the heating elements connected to the electronic interface box. The description of this variant, differing in particular from the above by the presence of studs, will also be made with reference to FIG. 5. In these figures, in particular, the stiffening element 44 is found in the form of a tank 440, as illustrated in FIG. 1, the bottom of which has an inner face 52 and an outer face 54.

The section of FIG. 4 also makes visible a heating element 4 and part of the electronic components housed in the housing 6, the electronic components represented here consisting of a printed circuit board 62 and connection terminals 68, soldered on the circuit board. printed circuits by each presenting two pins 39 brought to cross the printed circuit board.

In this alternative embodiment, the inner face 52 of the bottom of the tank 440 has studs 56 which extend respectively in longitudinal projection of this inner face 52. The studs 56 are distributed on the inner face 52 of the bottom of the tank 440 in a first row 55 and a second row 57. The arrangement of the first row 55 and the second row 57 on the inner face 52 of the bottom of the tank 46 will be explained in more detail in the detailed description of Figure 5. The FIG. 4 shows a heating element 4 visible at its distal end 20.

This has a tube 22 inside which are arranged two electrodes 37 which enclose resistive elements between them. A longitudinal end of each of the electrodes extends beyond the tube 22 and each longitudinal end is extended by a connection terminal 24 able to be inserted in one of the connection terminals 68 previously described. It is understood that the front view of FIG. 4 only makes visible one of the two electrodes housed in the tube 22, only the connection terminal 24 of the second electrode here hidden by the first electrode being visible.

It should be noted that to ensure a reliable electrical connection, the connection terminal of each electrode of a heating element must be fully inserted into the corresponding connection terminal, for example to allow a snap of cooperating means between the two terminals here not shown. During assembly of the electric heating device, the frame 2 and the heating elements 4 housed inside the frame are thus attached opposite the base 26 of the housing 6 and an appropriate tool 100 placed against the element of stiffening 44, here against the bottom wall 46 of the tank 440, prevents the housing from escaping under the effect of the thrust of the frame and the heating elements. As may have been clarified before, it will be understood from reading FIG. 4 that, independently of the studs illustrated, the local stiffening zone is advantageous in that it makes it possible to break the flatness of the surface of the cover against which must be supported by the tool 100, and in that it allows the tool to be positioned vertically and transversely with respect to the heating elements and with respect to the force of insertion of the electrodes of these heating elements in the housing.

For a given tube 22, which extends mainly longitudinally, the two connection terminals 24 are offset with respect to each other as well transversely, due to the presence of the electrodes against each two opposite walls of the tube, that vertically, as is more particularly visible in FIG. 4. It is understood that these characteristics also apply to connection terminals 68 due to their respective cooperation with a connection terminal 24 of a plurality of heating elements 4. In this way, the connection terminals, integral with the printed circuit board are arranged in two rows, a first row 67 and a second row 69, parallel to each other. The first row 67 and the second row 69 will be visible in FIG. 5 in dotted lines, to illustrate the offset during assembly between the pads and the connection terminals, and more particularly the pairs of pins of the connection terminals.

FIG. 4 also illustrates the printed circuit board 62, which has two faces, an upper face 64 facing the inner face 52 of the tank 440 is a lower face 66 facing the heating elements 4.

The studs 56 projecting from the stiffening element have here a cylindrical shape and they have a free end face 560, opposite the stiffening element. Each stud 56 here has a height substantially equal to its diameter, the height being the dimension defined longitudinally as that of the projection perpendicular to the bottom wall of the tank.

The stiffening element 44 from which the studs extend here has the shape of a tank, the bottom 46 of which extends along a plane CD, parallel to the plane AB of the central part 40. The pads 56 are positioned, when the electric heating device is assembled, so that the free end face 560 is as close as possible, advantageously in contact with the upper face 64 of the printed circuit board 62. In particular, clipping the cover onto the base ensures contact of the free end face with the printed circuit board. In this way, it is ensured that this contact is effective during the assembly of the frame and the heating elements with the electronic interface box.

It is advantageous that the free end faces of the pads are arranged in contact with the printed circuit board so that, once the heating device has been assembled, the pads can form a stop for excessive movement of the frame and the heating elements relative to to the electronic interface box, so as to avoid a risk of shearing at the terminal junctions.

According to another embodiment not illustrated, the connection terminals 68 can be in contact only with the lower face 66 of the printed circuit board 62. Still according to this other embodiment not illustrated, the inner face 52 of the bottom of the tank 46 may not have studs 56, the inner face 52 of the bottom of the tank 46 then being positioned facing the printed circuit board, as close as possible thereto, advantageously in contact with the upper face 64 of the printed circuit board 62. FIG. 5 shows the cover 34 at a perspective angle making visible the inside face of the cover capable of being turned towards the housing 6.

The central part 40, on this inner face, of the cover 34 has stiffeners 58 arranged here in a grid. The stiffeners 58 make it possible to limit the deformation of the cover 34 and to increase its impact resistance. The central part 40, on this inner face, also has two support ribs 60. A first support rib 60 is located in the first portion 48 of the cover 34 and a second support rib 60 is located in the second portion 50 of cover 34.

The support rib 60 has the function of forming a support stop for the printed circuit board 62 placed in the housing 6, in order to prevent it from bending. FIG. 5 makes it possible to observe that all of the studs 56 are disposed within the extent defined by the stiffening element 44. As has been described previously, the plurality of studs 56 are arranged in two rows forming two straight lines, a first row 55 and a second row 57. The first row 55 and the second row 57 are spaced apart vertically being parallel to each other and they are positioned so that each stud in the first row is transversely offset from the plane immediately next to the other row.

Note also in FIG. 5, dotted circles which represent the pairs of pins 39 of the connection terminals 68 arranged in a first row 67 and a second row 69, when the electric heating device 1 is assembled. This makes visible the characteristic that the pads are offset relative to the pairs of pins when the heating device is assembled, which allows the free end faces of the pads to be as close as possible to the printed circuit board.

During assembly of the cover on the base, which is produced by snap-fastening of the pins 30 in the tongues 38, the studs are housed between the pins of the connection terminals, without coming into contact with these pins.

FIG. 6 illustrates an alternative embodiment of the cover, in which the stiffening element 44, obtained by deformation of the cover, is associated with a network of reinforcing ribs 600, 610. In the example illustrated, the reinforcing ribs are arranged in a grid pattern, with a plurality of transverse ribs 600 and a plurality of vertical ribs 610. It is understood that the reinforcing ribs may consist only of transverse ribs or only of vertical ribs, or alternatively consist of ribs produced diagonally in an arrangement here not shown.

FIG. 7 illustrates an example of longitudinal dimension of the reinforcing ribs 600, 610 when these are produced in combination with a stiffening element

44 forming a tank. In this example, the free ends 620 of the reinforcing ribs 600, 610 protrude from the plane of the central part 40 of the cover, but it will be understood that one could have free ends at the height of the plane of this central part. In both cases, the reinforcing ribs 600, 610 have a double effect, namely on the one hand reinforcing the stiffening element 44 and on the other hand providing a contact surface to the tool 100 outside the housing. In another alternative, one could have ribs which remain in the volume of the tank, the free ends remaining below the plane of the central portion of the cover so that the reinforcing ribs essentially have the role of stiffening the cover.

Figures 6 and 7 illustrate the presence of reinforcing ribs in a stiffening element in the form of a tank, towards the inside of the housing, the reinforcing ribs originating on the bottom wall of the tank. Consideration could be given to associating such reinforcing ribs with a stiffening element in the form of a boss, towards the outside of the housing, the reinforcing ribs originating on the top of the boss.

The present invention thus provides a simple and inexpensive means for providing a robust electric heating device, in a context of high voltage electric heating in which operational safety is an essential point.

The present invention cannot however be limited to the means and configurations described and illustrated here, and it also extends to any equivalent means and configuration and to any technically effective combination of such means.

Claims

1. Electric heating device (1) for heating a through air flow, composed of a frame (2) integrating at least one heating element (4), the at least one heating element (4) s' extending longitudinally in the frame (2) and of an electronic control interface box (6) comprising a base (26), configured to house electronic control components of the at least one heating element, and a cover ( 34), the cover (34) comprising a peripheral portion (36) for fixing to the base (26) and a central part (40) for covering the electronic components of the housing (6), characterized in that the cover (34 ) has a substantially planar surface extending mainly along a first plane (AB) and at least one local stiffening element (44) forming in the central part (40) a bearing surface for a tool (100) for the outside of the housing, said bearing surface extending in decaf longitudinal length of the foreground (AB) of the hood.

2. An electric heating device (1) according to the preceding claim, in which the stiffening element (44) is obtained by deformation of the cover (34).

3. An electric heating device (1) according to claim 1 or 2, wherein at least two heating elements (4) are stacked in series along a first dimension of the frame (2), and the stiffening element (44) s 'extends in a direction corresponding to said first dimension of the frame over the same length as that of the stack of at least two elements (4).

4. Electric heating device (1) according to any one of the preceding claims, in which the stiffening element (44) obtained by deformation of the cover (34) has the shape of a tank (440) extending in protrusion from the flat surface of the cover towards the inside of the housing (6), the tank (440) comprising a bottom (46) which forms the bearing surface for the tool (100).

5. An electric heating device (1) according to the preceding claim, in which the bottom (46) of the tank (440) forming the stiffening element (44) obtained by deformation of the cover (34) has an inner face (52 ) facing the electronic components housed in the electronic interface box (6) and an opposite external face (54), the internal face (52) having at least one stud (56) which projects from this face interior (52) and which extends towards the interior of the housing (6).

6. Electric heating device (1) according to claim 5, wherein the electronic interface comprises a printed circuit board (62) having an upper face (64) and a lower face (66), so that the upper face is the face of the printed circuit board facing the cover (34) and that the underside is the face of the printed circuit board facing the frame (2), the at least one stud (56) being configured to make a bearing surface on the upper face (64) of the printed circuit board (62) during assembly of the frame and the heating elements on the housing.

7. An electric heating device (1) according to one of claims 5 or 6 in which at least one stud (56), of cylindrical shape, has a height substantially equal to its diameter.

8. An electrical heating device (1) according to one of claims 5 to 7, in which several studs (56) project from the cover towards the inside of the housing, all of these studs being arranged on the inner face (42) of the stiffening element (44).

9. Electric heating device (1) according to one of the preceding claims, in which reinforcing ribs (600, 610) extend in or on the stiffening element (44), facing outwards from the housing. .

10. Electric heating device (1) according to the preceding claim, in combination with claim 5, wherein the frame (2) has a plurality of heating elements (4) arranged in transverse series in the frame (2), each heating elements (4) having a proximal end (18) and a distal end (20), each of the distal ends (20) of each of the heating elements (4) comprising two connection terminals (24) capable of being inserted in connection terminals (68) integral with the printed circuit board (62) housed in the electronic interface box (6), all of the connection terminals (68) forming on one face of the printed circuit board opposite of the cover (34) a first row (67) and a second row (69) parallel and offset from one another, the plurality of studs (56) also forming two rows (55, 57) parallel and offset from each other so that in an assembled position of the housing (6) with the frame (2), the connection terminals (68) and the studs (56) are arranged alternately.

11. An electric heating device (1) according to claim 1, in which the local stiffening element (44) is a set of ribs turned towards the outside of the electronic interface box (6).