FR3078017A1 - FRAME FOR AN ELECTRICAL HEATING DEVICE COMPRISING AT LEAST ONE DEVICE FOR ELASTICALLY HOLDING HEATING ELEMENTS - Google Patents

Abstract

A frame (3) of an electrical heating device (1) for a flow of air circulating inside a ventilation, heating and / or air-conditioning system of a motor vehicle comprises at least one heating compartment (30) having at least one housing (7) for receiving a heating element (5), the housing (7) being defined at least by two longitudinal walls (23, 25) transversely delimiting an insertion path for the heating element (5), each longitudinal wall (23, 25) comprising an inner face (230, 250) oriented towards the insertion path, At least one of the longitudinal walls (23, 25) comprises a flexible portion (40 ) whose thickness (E40) according to the transverse dimension is smaller than the thickness (E) of the remainder of said longitudinal wall, said flexible portion (40) having a boss (42) which projects from the inner face (230, 250) of the flexible portion.

Description

The invention relates to electric heating devices, in particular for a heating, ventilation and / or air conditioning installation of a motor vehicle.

The heating of the air intended for heating the passenger compartment of a motor vehicle with an internal combustion engine, as well as for demisting and defrosting the glazed surfaces, is ensured by heat exchange between an air flow and a cooling of the heat engine circulating in a heat exchanger.

When the engine is started and for a certain period of time following the starting time, the calories transported by the engine coolant are insufficient to ensure rapid and efficient heating of the air brought into the passenger compartment. This is observed more particularly with certain types of engine and has a disadvantage in cold weather, because not only the internal temperature of the passenger compartment cannot be raised quickly, but also the functions of demisting and defrosting cannot be effectively ensured.

To remedy these drawbacks, it has been proposed to mount an additional electric heating device in the air flow directed towards the passenger compartment.

Such an additional electric heating device generally comprises a frame inside which are arranged a plurality of heating elements arranged respectively in a housing defined by walls of the frame. Each heating element, or heating rod, comprises parallel conductive plates between which are mounted resistive heating elements, for example resistors with positive temperature coefficient (PTC), and radiant elements attached to these conductive plates and increasing the surface of heat exchange with the air flow passing through the electric heater. Each heating element is inserted into its own housing, then connected to an electrical connection element for supplying the resistive heating elements. The manufacturing clearances of these housings formed in the frame and of the elements generate a mounting clearance for the heating element which can be arranged at a distance from the longitudinal walls delimiting the housing, so that these heating elements can debate and generate noise during of the vehicle running.

An electric heating device frame can be equipped for this purpose, that is to say avoid the deflection of the heating elements, of means for holding in elastic position which consist of tongues whose free end is arranged across the housing and the path for inserting the heating elements, the free end tending to retract during the passage of the heating element and then pushing against this heating element against one of the walls of the housing to keep it in position under the effect of the recall in elastic position. These tongues are made integral with a wall defining the housing at one of their ends and they are free at the opposite end, and they have in their original position an arrangement such that the free end is released from the wall defining housing. 11 results in a brittleness which can result in the breakage of this elastic tongue and in the loss of the function of holding in position of the heating elements.

An alternative is known in which the frame comprises means for plastic deformation of the heating elements, arranged projecting from the walls participating in delimiting the housing in which the heating element is inserted. These plastic deformation means make it possible to constrain and plastically deform each heating element in the direction of the opposite wall of the housing, in particular when they are inserted into the housing. These plastic deformation means allow the heating elements to be pressed into the housing while eliminating elastic elements which exert elastic restoring forces on the heating elements which are liable to break. However, the insertion of the heating elements into the heating body being done by a robot, the meeting of the heating elements with the plastic deformation means has the consequence of considerably increasing the insertion forces. The sensors fitted to the robot repeatedly detect that the increase in insertion forces corresponds to an abutment of the heating elements in the heating body. For security reasons, this abutment detection forces the robot to stop, so that an operator can verify it. Stopping the robot and verifying it by the operator interrupts the production chain, which generates a waste of time and a manufacturing cost.

In this context, the invention aims to propose an alternative to existing solutions which allow efficient and reliable maintenance of the heating elements in the context of the electric heating device.

To this end, the invention provides a frame for an electric heating device for an air flow circulating inside a ventilation, heating and / or air conditioning installation of a motor vehicle, said frame comprising at least one heating compartment having at least one housing intended to receive a heating element, the housing being defined at least by two longitudinal walls transversely delimiting an insertion path for the heating element, each longitudinal wall comprising an internal oriented face towards the insertion path. According to the invention, at least one of the longitudinal walls has a flexible portion whose thickness along the transverse dimension is less than the thickness of the rest of said longitudinal wall, said flexible portion comprising a boss which projects from the internal face of the flexible portion.

The flexible portion and the associated boss form an elastic holding device for the heating element during its insertion. The boss is defined so as to extend at least partially inside the insertion path, to be constrained by the heating element during its passage. It is understood that this results in a force borne on the boss and tending to push it out of the insertion path, in particular due to the movement of the heating element. The boss is carried by a portion of small thickness, or at least of thickness less than that of the longitudinal wall in which it is integrated, so that flexibility is given to this portion of wall and that can accompany the movement of withdrawal of the boss out of the insertion path. The deformation is elastic so that the flexible portion tends to return to its original position, in the plane of the longitudinal wall, and so that the boss tends to return to its position inside the housing, pushing the heating element against the opposite longitudinal wall. This reduces the travel of the heating element inside the associated housing made possible by the manufacturing and mounting games of the frame and the heating element.

According to one or more characteristics which can be taken alone or in combination, provision may be made for:

- At least part of the boss is located inside the housing, across the path of insertion of the heating element, said part of the boss being intended to come into contact with the heating element when it is inserted into the housing.

- Each internal face of a longitudinal wall is delimited vertically by two end edges extending longitudinally, with a first end edge located opposite a second end edge.

- The flexible portion extends vertically over the entire vertical dimension of the longitudinal wall, from the first end edge to the second end edge, or over a portion of this vertical dimension of the longitudinal wall.

- The boss extends over the entire vertical dimension of the flexible portion.

- The flexible portion is held at its two longitudinal ends in the corresponding longitudinal wall, in which it fits. In other words, the flexible portion is free on its vertical sides, and it is configured to elastically debate in the transverse direction.

- Two longitudinal walls, including a first longitudinal wall and a second longitudinal wall, delimiting the same housing each include at least one flexible portion and an associated boss.

- At least one boss is provided in the vicinity of a bottom wall participating in delimiting each housing with the longitudinal walls.

- The same longitudinal wall comprises at least two bosses arranged successively in the insertion path.

- The frame comprises a plurality of flexible portions and associated bosses formed in the same housing and, depending on the direction of insertion of a heating element in the housing, the bosses have increasingly greater heights.

- The longitudinal wall comprising the flexible portion and the associated boss participate in delimiting two housings, the internal face being turned towards a first housing and the external face being turned towards a second housing. The flexible portion may comprise a first projection projecting from the internal face of the flexible portion, arranged at least partially across the insertion path defined by the first housing, and a second projection projecting from the external face of the flexible portion , arranged at least partially across the insertion path defined by the second housing.

- The longitudinal wall comprising the flexible portion and the associated boss participate in defining a housing, on the side of the internal face, the external face of the longitudinal wall participating in delimiting an air passage zone formed by an openwork plate. The perforated plate has a recess forming a clearance zone directly in the vicinity of the flexible portion.

The invention also relates to an electric heating device comprising at least one heating element and a frame defining at least one housing for receiving the heating element, characterized in that the frame is as defined above and in that the at least one heating element is held in position in the corresponding housing by an elastic return force generated by a flexible portion and a boss.

Other characteristics and advantages of the present invention will appear more clearly with the aid of the description and the drawings, among which:

- Figure 1 is a front view of an electric heating device according to a first embodiment of the invention, comprising a frame in which three heating elements have been inserted and at one end of which is fixed an electrical connection interface , the heating elements being separated from each other by an air passage zone formed by an openwork plate;

- Figure 2 is a perspective view of a detail of the frame of Figure 1 without the heating elements, so as to make visible elastic retaining devices of each of these heating elements;

- Figure 3 is a front view of an electric heating device according to a second embodiment of the invention, comprising a frame in which two heating elements, one with two radiant elements and the other with three elements radiant, have been inserted and at one end of which is fixed an electrical connection interface, the heating elements being separated from one another by a longitudinal wall of the frame;

- Figure 4 is a detail view of the longitudinal wall of the frame illustrated in Figure 3> without the heating elements so as to make visible a first variant of an elastic holding device for these heating elements; and

- Figure 5 is a view similar to that of Figure 4> in which there is illustrated a second variant of elastic holding device of the heating elements.

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. However, it should be noted that these figures show only part of the possible embodiments according to the invention.

In the description which follows, reference will be made to an orientation as a function of the longitudinal axes L, vertical V and transverse T, as defined by the trihedron L, V, T shown in the figures. The longitudinal axis L corresponds to the direction of elongation of the frame of the electric heating device, the vertical axis V perpendicular to the longitudinal axis L, corresponds to the direction followed by the flow of air to be heated passing through the device. heating, and the transverse axis T is perpendicular to both the longitudinal axis L and the vertical axis V. 11 It should be noted that the choice of names for these axes is not limiting of the orientation that can take the electric heating device in its application to a motor vehicle.

An electric heating device 1 according to the invention comprises a frame 3 into which heating elements 5> capable of transforming an electric current into thermal energy, can be inserted. To ensure the position of the heating elements once they are inserted into their respective housings, the frame 3 includes elastic retaining devices 4 which will be described in detail below.

The electric heating device 1 is intended to be housed in an air circulation duct of a ventilation, heating and / or air conditioning installation, so as to transform the electrical energy taken from the vehicle into returned thermal energy in the air passing through this conduit. The installation is not shown here, but it will be understood that a main duct of this installation conventionally comprises an opening made in the wall of the duct for the insertion of the electric heating device.

We will first describe the electric heating device according to a first embodiment illustrated in FIGS. 1 and 2.

The heating elements 5 comprise means capable of exchanging heat, such as radiant elements 53 making it possible to increase the heat exchange surface, with the air flow passing through the electric heating device 1. The heating elements 5 comprise also electrodes 54 between which are arranged resistive heating elements, for example resistors with a positive temperature coefficient 55 (PTC), and against which the radiant elements are fixed 53 · The electrodes 54 and the PTC resistors 55 make it possible to transform a current electric in thermal energy to be transferred to the air flow passing through the electric heating device. It should be noted that the resistors with a positive temperature coefficient 55 can be bonded directly to the radiant elements 53 ·

The frame 3 includes a heating compartment 3θ> forming a receiving casing for the heating elements 5> and a connection interface 100 formed at one of its ends. The heating elements 5 are inserted in housings 7 formed inside the heating compartment 3θ · It is understood that the connection interface 100 comes to close an access by which the heating elements 5 are inserted in the housings 7 of the heating compartment 3θ at the same time as it allows the connection of the electrical heating device 1 to an electrical network of the vehicle allowing the electrical supply of the heating elements 5 ·

The frame 3 and the heating compartment 30 have the shape of a rectangular parallelepiped. The two main faces of the frame 3> respectively front and rear, opposite along the vertical axis V, are perforated to allow the passage of the air flow to be heated and a diffusion of heat in the duct where the electric heating device 1 is installed. The frame 3 comprises a median plane corresponding to a plane passing through one half of the frame and being perpendicular to the vertical direction followed by the air flow circulating through the electric heating device 1. It is understood that the front and rear faces of the frame 3 extend in planes parallel to the median plane.

In the embodiment illustrated in Figures 1 and 2, it is also noted that the frame 3 comprises perforated plates 9 disposed between each housing 7 and extending in the median plane of the frame 3 · These perforated plates 9 participate in the stiffening of the frame 3 and form air passage zones. In the example illustrated, the perforated plates take the form of bars comprising ventilation slots 90 allowing the air flow to flow through, the ventilation slots 90 are positioned one after the other according to the longitudinal axis L of the heating device 1. It will be understood that the perforated plates can take the form of plates perforated with holes of circular section, or of any other shape, without departing from the context of the invention.

The housings 7 of the frame 3 are defined by longitudinal walls 23, 25 extending along the longitudinal axis L. More precisely, each housing is defined by two longitudinal walls 23, 25, including a first longitudinal wall 23 and a second wall longitudinal 25 transversely delimiting an insertion path for the heating element 5 · The insertion path is the path taken by the heating element 5 during its insertion. In other words, the insertion path corresponds to a volume occupied by the heating element 5 during its insertion. Thus, the spacing between the first longitudinal wall 23 and the second longitudinal wall 25 of the same housing 7 corresponds to the transverse dimension of the heating element 5> apart from the manufacturing clearance. According to the exemplary embodiment illustrated in FIGS. 1 and 2, the frame 3 comprises three housings 7 with a central housing and two lateral housings located on either side of the central housing.

Each longitudinal wall 23, 25 comprises an internal face 230, 250 oriented towards the insertion path. Each internal face 230, 250 is delimited by two end edges 23a, 23b, 25a, 25b extending longitudinally. More precisely, these end edges 23a, 23b, 25a, 25b correspond to edges of the longitudinal walls 23, 25 · For the internal face 230 of the first longitudinal wall 23, a first end edge 23a is located located at the opposite a second end edge 23b (see Figure 2). Similarly, for the second internal face 250 of the second longitudinal wall 25, a first end edge 25a is defined which is opposite to a second end edge 25b.

Each housing 7 is further delimited by a bottom wall 21 extending along the transverse axis T. This bottom wall 21 is located opposite an opening 50 through which the heating elements 5 enter the compartment. heater 30 and which is intended to be covered by the connection interface 100. It should be noted that the heating elements 5 are inserted into the housings 7 in a direction of insertion parallel to the longitudinal axis L, the direction d insertion being defined from the opening 50 towards the bottom wall 21.

Abutment elements 210 may extend from the bottom wall 21, in the direction of the opening 50. In other words, each abutment element 210 extends along the longitudinal axis L towards the interior of the housing 7 · Two abutment elements 210 can be provided per housing 7 · In general, the number of abutment elements 210 in a housing 7 is equal to the number of radiant elements 53 equipping the element heater 5 intended to enter this housing 7 ·

The frame 3 also includes ribs 6, 8 vertically delimiting the path of insertion of the heating element 5 · For this, the ribs 6, 8 extend in a plane defined by the transverse axis T and the longitudinal axis L, also called transverse plane, perpendicular to the longitudinal walls 23, 25 · Among these ribs 6, 8, there are ribs extending partially between two longitudinal walls 23, 25 forming the same housing 7> called guide ribs 6 in the continuation of the description, and ribs extending at least between two longitudinal walls 23, 25 forming the same housing 7> called stiffening ribs 8. The spacing between two ribs 6, 8, whether they are guiding or stiffening, located on either side of the insertion path along the vertical axis V corresponds to the vertical dimension of the heating element 5> apart from the manufacturing clearances.

The stiffening ribs 8 connecting the two longitudinal walls 23, 25 participate in the stiffening of the frame 3 and the heating compartment 30. According to the illustrated embodiment, the guide ribs 6 and the stiffening ribs 8 extend to from an end edge 23a, 23b, 25a, 25b of the internal faces 230, 250 and projecting from the corresponding internal face.

According to the invention and in order to ensure the maintenance in position of the heating elements inside their housing between the longitudinal walls 23, 25 participating in delimiting the housing, the frame 3 comprises as has been specified above at least one elastic retaining device 4 formed on at least one of the longitudinal walls so as to extend at least partially across a housing 7 so as to be in the passage of a heating element 5 during its insertion and to be elastically deformed by this passage.

As is more visible in FIG. 2, it can be seen that each elastic holding device 4 comprises a flexible portion 4θ and a boss 42, the holding device being configured so that the flexible portion 4θ is arranged at rest in the plane of the corresponding longitudinal wall and so that the boss 42 is arranged projecting from the longitudinal wall to be at least partially across the insertion path.

The flexible portion 4θ is particular in that it consists of a portion of a longitudinal wall 23, 25 whose thickness E40 is reduced compared to the rest of the longitudinal wall, that is to say relative to the 'average thickness E of the longitudinal wall which comprises this flexible portion. The difference in thickness between the flexible portion 40 and the rest of the longitudinal wall generates drop-out zones by reduction in thickness 41 (in particular visible in FIGS. 4 and 5) at the level of the internal face of the longitudinal wall and / or at the level of the external face.

It is understood that the lesser thickness of the flexible portion 40 relative to the longitudinal wall in which it is inscribed gives flexibility to the flexible portion, capable of deforming under the effect of a force undergone by the boss 42 than she wears.

The flexible portion 40 is according to the invention maintained at its two longitudinal ends in the longitudinal wall. There is a continuity of material between the flexible portion and the longitudinal wall upstream and downstream of this flexible portion, the assembly being in one piece. The flexibility of the portion carrying the boss is generated by the reduction in section at the junction of the flexible portion and the longitudinal wall which carries it.

The elastic holding device 4 is thus configured to pass from an original position in which the flexible portion 40 is arranged in the continuity of the longitudinal wall, that is to say inscribed in the plane defined by this longitudinal wall, to a retracted position in which the flexible portion bulges to extend away from the housing relative to the longitudinal wall and allow the boss to move away from the housing. The fact that the flexible portion is held at its two ends by the longitudinal wall tends to recall the flexible portion 40 in the original position and therefore to recall the boss 42 across the housing.

In order to allow a sufficiently large elastic deformation of the flexible portion ίο to allow the release of the boss 42 along the path of insertion of the cbauffant element 5, one can provide a clearance area. In the first embodiment illustrated in FIGS. 1 and 2, the longitudinal wall comprising the flexible portion 40 and the associated boss 42 participates in delimiting a single housing 7 on the side of its internal face 230, 250, on which the boss is formed. . The external face 232, 252 opposite this longitudinal wall is extended perpendicularly by one of the perforated plates 9 mentioned above, participating in delimiting an air passage zone between the housings. The clearance zone necessary for the elastic deformation of the flexible portion 40 is produced by a recess 92 of the perforated plate 9 directly in the vicinity of the flexible portion, that is to say directly in the continuity of the flexible portion according to the transverse direction T.

The flexible portion 40 may extend vertically from the first end edge 23a, 23b, 25a, 25b of the corresponding longitudinal wall 23, 25 to the second end edge 23a, 23b, 25a, 25b opposite, or alternatively s 'partially extend over the vertical dimension of the corresponding longitudinal wall. Furthermore, the boss 42 can extend partially or over the entire vertical dimension of the flexible portion previously defined. In FIG. 2, an embodiment is shown in which the flexible portion extends partially over the vertical dimension of the corresponding longitudinal wall and in which the boss extends over the entire vertical dimension of the flexible portion 40.

The boss 42 is formed on the internal face 230, 250 of the longitudinal wall, at the level of the flexible portion 40.

The thickness E of the boss is such that the boss 42 extends at least partially across the insertion path, so that the heating element inserted in the housing up to the bottom wall 21 comes into contact with the boss 42. The elastic nature of the flexible portion 40 ensures, once the cbauffant element 5 has been inserted, the return in position of the elastic holding device 4 in its original position, that is to say -to say with the boss 42 in the housing across the insertion path, and therefore the contact of the boss 42 against the cbauffant element 5 · 11 is notable that the prominence formed by the boss 42 tends to push the cbauffant element in direction of the opposite longitudinal wall.

Each boss 42 extends projecting from a longitudinal wall 23, 25 participating in defining the housing 7, in particular having at least one downstream face 420 and a free end face 421, each of these faces being intended to be at at least partially in the housing 7 in the original position of the boss 42, so as to come into contact with the heating element 5 ·

More specifically, the downstream face 420 has a profile inclined relative to the transverse direction. It is understood that during the insertion of the heating elements, it is this downstream face 420 which is the first in contact with the end of the heating element and the ramp shape created by this inclined profile allows contact without generating d 'excessive effort to retract the boss in the passage of the heating element.

Furthermore, the free end face 421 is here curved, so that a vertical linear contact is exerted on the heating element when the elastic restoring force in position of the elastic holding device 4 tends to press the boss 42 against the heating element 5 ·

The thickness E42 of the boss represents the distance between the face of the flexible portion 40 on which the boss 42 is located and the point forming the top of the free end face 421. In order to ensure contact between the heating element 5 and the boss 42 during the insertion of the heating element, and therefore ensuring a deformation of the elastic holding device and the creation of a restoring force making it possible to participate in keeping the heating element in position, the thickness E42 of the boss 42 is defined taking into account the chains of ribs of the heating elements 5 and the dimensions of the corresponding housings 7. More precisely, the thickness E42 of the boss 42 is at least equal to the difference between the transverse dimension of the housing 7 and the transverse dimension of the heating element 5 · More precisely still, it is necessary to take account of the reduction in thickness of the flexible portion 40 from which the boss 42 extends. If the face of the flexible portion from which the boss extends is set back with respect to the internal face of the corresponding longitudinal wall, the thickness E42 of the boss is at least equal to the difference between on the one hand the sum of the transverse dimension of the housing 7 and the withdrawal of the face of the flexible portion with respect to the corresponding face of the longitudinal wall and on the other hand the transverse dimension of the heating element 5 ·

According to the embodiment illustrated in Figure 3, a single elastic holding device 4 is provided on a single longitudinal wall 23, 25 for a defined housing. In other words, there is associated with each housing a single holding device.

This boss 42 can in particular be formed in the vicinity of the bottom wall 21 participating in delimiting each housing 7 with the longitudinal walls 23, 25 · The effort to hold in position is thus exerted at the end of insertion of the heating element in housing, and we reduce the effort to provide to perform this mounting operation. By in the vicinity of the bottom wall, it is understood that the boss can extend at a distance less than 25 mm from the bottom wall, in particular to be advantageously between 5 and 15 mm from the free end of the element corresponding heater opposite this bottom wall.

In the case where the same longitudinal wall comprises two elastic holding devices 4, as illustrated in FIG. 1, provision can be made for dimensioning one and the other of the bosses corresponding to these holding devices differently, with, according to the direction of insertion of the heating element 5 into the housing 7, shown by way of example by the arrow S in FIG. 2, the two bosses which have thicknesses which are increasingly greater, the thickness being measured as as described above from the longitudinal wall carrying the boss and along the transverse axis T.

According to a variant here not shown, the two longitudinal walls 23, 25 participating in delimiting the same housing 7 may each comprise at least one flexible portion 40 and a boss 42 associated to form an elastic holding device for the heating element brought to be inserted in this housing. In this case, it will be possible to provide less prominent boss thicknesses 42.

We will now describe a second embodiment with reference to Figures 3 to 5, which differs from the above in the arrangement and size of the housings and the number of heating elements arranged in these housings. Contrary to the above, no perforated plate is disposed in the vicinity of a housing, and a longitudinal wall 23, 25 can make it possible to delimit two neighboring housing, with the internal face which participates in defining a first housing 7 and the face external which participates in defining a second housing 7 ′, as visible in particular in FIGS. 4 and 5.

It is therefore understood that the creation of a specific clearance zone to allow the elastic deformation of the flexible portion is no longer necessary, the flexible portion being able to debate on either side of the longitudinal wall due to the manufacturing clearance originally present between the housing and the heating element to be inserted in this housing.

In FIG. 4, a first variant is illustrated in which the flexible portion 40 comprises a single boss 42. In this way, the flexible portion illustrated is capable of holding in position only a heating element, that is to say the heating element inserted in the housing in which this single boss extends. It is therefore understood that another elastic holding device must be provided to hold the other heating element in position brought to be inserted in the other housing.

In FIG. 5, a second variant has been illustrated in which the flexible portion 40 comprises a first boss 42 projecting from the internal face 230, 250 of the flexible portion, arranged at least partially across the insertion path defined by the first housing, and a second boss 42 'projecting from the external face 232, 252 of the flexible portion, arranged at least partially across the insertion path defined by the second housing 7' · In this way, the same device elastic retention can participate in maintaining in position two heating elements in two neighboring housings, the flexible portion 4θ taking a final mounting position not necessarily in the extension of the longitudinal wall, taking into account the different manufacturing clearances which may exist in a housing to another and from one heating element to another.

it should be noted that in these variants of the second embodiment, the free end face 421 is here flat, so that a flat support is generated in contact with the heating element when the elastic return force in the position of the elastic retaining device 4 tends to press the boss 42 against the heating element 5 ·

We will now describe the assembly of the electric heating device 1 comprising the frame 3 according to the invention, with reference to FIG. 2. It will be understood that the assembly described below is substantially similar depending on whether the device is produced according to the first mode or the second embodiment described above, or alternatively according to a possible alternative embodiment of these embodiments.

The heating elements 5 are firstly inserted into the appropriate housings 7 inside the heating compartment 3θ · For this, the heating elements 5 are inserted through the opening 5θ formed at one end of the frame 3, and the heating elements 5 are slid in translation towards the bottom wall 21 of the housing 7, in particular according to the direction of insertion materialized by the arrow S. When passing the bosses 42 and more particularly in contact with the top of these bosses, c that is to say the innermost portion of the housing, the heating elements 5 and in particular the radiant elements 53 facing the boss 42 are slightly pushed in the direction of their initial trajectory to be pressed against the opposite longitudinal wall. Due to the rigidity of the heating element 5 and the deformable nature of the flexible portion which carries the boss, the latter tends to retract from the passage and the flexible portion folds for this purpose, away from the housing in which is inserted the heating element.

As may have been specified previously, the reduction in thickness between the longitudinal wall and the flexible portion contributes to generating an elastic deformation, so that the elastic return force tends to bring the flexible portion back into the plane defined by the longitudinal wall and tends to push the heating element against the opposite longitudinal wall.

According to the embodiment illustrated in FIG. 2, the insertion of the heating elements 5 is also carried out by meeting, where appropriate, the guide ribs 6 and the stiffening ribs to direct them vertically. These ribs 6, 8 prevent the heating elements 5 from coming out of their insertion path and the insertion continues up to the bottom wall 21.

Once inserted, each heating element 5 remains in contact with the top of the boss or bosses 42 and the elastic nature of the flexible portion, which tends to return the latter to its original position in the plane of the longitudinal wall, pushes the boss 42 against the heating element. In this position, the heating elements 5 are constrained in their housing 7 by the elastic nature of the elastic holding means 4 ·

The connection interface 100 is then placed at one end of the heating compartment 3θ and allows the connection of the electric heating device 1 to an electrical network of the vehicle. The heating device 1 is then inserted into a duct of the heating-ventilation and / or air-conditioning installation.

The foregoing description clearly explains how the invention makes it possible to achieve the objectives which it has set itself, and in particular to propose a heating device 1 in which the heating elements 5 are easily inserted and do not debate inside. their accommodation.

The invention as it has just been described cannot be limited to the means and configurations exclusively described and illustrated, and also applies to all means or configurations, equivalent and to any combination of such means or configurations. Likewise, if the invention has been described here according to variant embodiments each implementing separately a type of arrangement of the flexible portions and associated bosses, it goes without saying that the different arrangements presented can be combined without harming the invention.

Claims (10)

1. Frame (3) of an electric heating device (1) of an air flow circulating inside a ventilation, heating and / or air conditioning installation of a motor vehicle, said frame (3) comprising at least one heating compartment (30) having at least one housing (7) intended to receive a heating element (5), the housing (7) being defined at least by two longitudinal walls (23, 25) delimiting transversely an insertion path for the heating element (5), each longitudinal wall (23, 25) comprising an internal face (230, 250) oriented towards the insertion path, characterized in that at least one of the walls longitudinal (23, 25) comprises a flexible portion (40) whose thickness (E40) along the transverse dimension is less than the thickness (E) of the rest of said longitudinal wall, said flexible portion (40) comprising a boss ( 42) which projects from the internal face (230, 250 ) of the flexible portion. 2. Frame according to claim 1, characterized in that at least a part of the boss (42) is located inside the housing (7), across the path of insertion of the heating element (5), said part of the boss (42) being intended to come into contact with the heating element (5) when it is inserted into the housing (7) · 3. Frame according to claim 1 or 2, wherein each internal face (230, 250) of a longitudinal wall is delimited vertically by two end edges (23a, 23b, 25a, 25b) extending longitudinally, with a first end edge (23a, 23b, 25a, 25b) located opposite a second end edge (23a, 23b, 25a, 25b), characterized in that the flexible portion (40) extends vertically from the first end edge (23a, 23b, 25a, 25b) to the second end edge (23a, 23b, 25a, 25b). 4. Frame according to any one of the preceding claims, characterized in that the boss (42) extends over the entire vertical dimension of the flexible portion (40) · 5. Frame according to any one of the preceding claims, characterized in that the flexible portion (40) is held at its two longitudinal ends in the corresponding longitudinal wall (23, 25). 6. Frame according to any one of the preceding claims, characterized in that at least one boss (42) is formed in the vicinity of a bottom wall (21) participating in delimiting each housing (7) with the longitudinal walls ( 23, 25) 7 A frame according to any one of the preceding claims, characterized in that the same longitudinal wall (23, 25) comprises at least two bosses (42) arranged successively in the insertion path. 8. Frame according to any one of the preceding claims, in which the longitudinal wall comprising the flexible portion (40) and the associated boss (42) participate in delimiting two housings (7, 7 '), the internal face (230, 250 ) being turned towards a first housing (7) and the external face (232, 252) being turned towards a second housing (7 '), characterized in that the flexible portion (40) comprises a first boss (42) projecting from the internal face (230, 250) of the flexible portion, arranged at least partially across the insertion path defined by the first housing, and a second boss (42 ') projecting from the external face (232, 252) of the flexible portion, arranged at least partially across the insertion path defined by the second housing (7 '). 9. Frame according to any one of the preceding claims, in which the longitudinal wall comprising the flexible portion (40) and the boss (42) associated participate in delimiting a housing (7) on the side of the internal face (230, 250) , the external face (232, 252) of the longitudinal wall participating in delimiting an air passage zone formed by an openwork plate (9), characterized in that the openwork plate (9) has a recess (92) forming a clearance zone directly in the vicinity of the flexible portion. 10. Electric heating device (1) comprising at least one heating element (5) and a frame (3) defining at least one housing (7, 7 ') for receiving the heating element, characterized in that the frame (3 ) is according to any one of the preceding claims and in that the at least one heating element (5) is held in position in the corresponding housing (7) by an elastic return force generated by a flexible portion (40) and a boss (42).