FR3083744A1 - VEHICLE ELECTRIC HEATING DEVICE FRAME - Google Patents

Abstract

The invention relates to a frame (3) of an electric heating device (1) configured to heat an air flow (FA) circulating in a housing (17) for the ventilation, heating and / or air conditioning installation of a vehicle. , the frame (3) being configured to receive a heating element (2) in a housing (4), the housing (4) being bordered by a first upright (10) of the frame (3) and by a second upright (11) of the frame (3), the frame (3) comprising two faces (5) and a rib (12) placed on one of the perforated faces (5), the rib (12) comprising a central part (18), a first lateral part (19) connected to the central part (18) and to the first upright (10), a second lateral part (20) connected to the central part (18) and to the second upright (11), characterized in that the part central (18) partly forms a curve. Application to motor vehicles.

Description

The field of the present invention is that of electric heating devices for vehicles. The invention applies more particularly to ventilation, heating, and / or air conditioning installations of motor vehicles comprising such devices making it possible to heat an air flow.

Electric heating devices of this type are 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, the hot air flow being intended for heating the passenger compartment of a motor vehicle, or also for demisting or defrosting the glazed surfaces of the vehicle. This heating is ensured by the passage of an external air flow through an electric heating device arranged in a ventilation, heating, and / or air conditioning installation otherwise called HVAC installation, for the acronym "Heating, Ventilating and Air-Conditioning ”.

The electric heating device comprises a frame, in which are housed heating elements supplied electrically via a suitable connector at the periphery of said frame. The frame supports the heating elements and the associated electrical connections, and it also allows the electric heating device to be fixed to the vehicle, for example within the vehicle's HVAC installation. The heating elements consist of metal fins that thermally collect and conduct the heat generated by ceramic stones with PTC effect, acronym for the English expression "Positive Temperature Coefficient". The PTC elements generate heat under the effect of an appropriate electrical supply and the metal fins forming radiant elements restore this heat to the air flow circulating in contact with them, so that at the outlet of the electric heating device in operation, the air flow is warmer than it entered.

The frame has the shape of a parallelepipedic structure, the two large faces of which are arranged across the flow of the air flow to be heated. For this purpose, these large faces are perforated to be traversed by the air flow.

In order to consolidate the structure of the frame of such an electric heating device, perforated to allow the circulation of the air flow, the large perforated faces of the frame are each stiffened by ribs. There are known from the prior art rectilinear ribs arranged perpendicular to the longitudinal walls of the frame. The only lateral arrangement, that is to say perpendicular to the longitudinal direction, of these ribs is calculated to be particularly effective in terms of reinforcement of the frame, without it being particularly considered other problems that may be the flow circulation air through the electric heater or ease of fabrication by molding the frame.

The aim of the present invention is therefore to propose an alternative to the electric heating devices known from the prior art which allows an optimal compromise between the stiffening of the frame, the impact of the presence of the ribs on the circulation of the air flow. and manufacturing, and which also makes it possible to limit the problems of inserting the heating elements during the assembly of the electric heating device.

The subject of the invention is therefore an electric heating device frame configured to heat a flow of air circulating in a vehicle ventilation, heating and / or air conditioning installation box, the frame being configured to receive at least a heating element in a housing extending along a longitudinal axis, the housing being bordered by a first amount of the frame and by a second amount of the frame, the frame having two perforated faces at the level of the housing and at least one rib placed on the 'one of the perforated faces, the rib comprising a central part, a first lateral part connected to the central part and to the first upright of the frame, a second lateral part connected to the central part and to the second upright of the frame, characterized in that the central part forms at least partly a curve.

The frame is a one-piece structure which includes the first upright and the second upright at the periphery of the housing. The housing extends along its own longitudinal axis, this longitudinal axis corresponding to the direction of insertion of the heating element into the housing. The first upright and the second upright are arranged substantially parallel to the longitudinal axis.

By monoblock is meant the fact that it is not possible to dissociate the constituent elements of the frame without degrading the structure. In particular, the frame is obtained by molding. The plastic material may in particular consist of polypropylene or polyamide, loaded with glass fibers. For example, the material used could be PA66 + GF3O.

The frame also has a first longitudinal end and a second longitudinal end which is opposite it relative to the longitudinal axis of the housing. The first longitudinal end is that which allows the insertion of the heating element into the housing. This first longitudinal end is for this purpose open. Conversely, the second longitudinal end corresponds to a bottom of the frame, intended to form a stop for the heating element at the end of its insertion into the housing.

The longitudinal axis is arranged in a median longitudinal plane of the frame which corresponds to the frame's extension plane in its largest dimension. The air flow intended to be heated circulates transversely to the frame, oriented perpendicular to the median longitudinal plane.

The faces of the frame are perforated so as to let the air flow pass through the housing, between the first upright and the second upright. Each rib of the frame is a stiffening rib of the openwork face which carries it and which therefore extends at least between the first upright and the second upright of a housing.

The rib is arranged in a main plane perpendicular to the air flow. In other words, the rib is arranged in a plane parallel to the median longitudinal plane of the frame. In particular, the rib is placed in the same plane as the openwork face which carries it.

The first lateral part and the second lateral part of the rib correspond to areas of attachment of the rib to the frame. More particularly, the first lateral part makes it possible to attach the rib to the first upright of the frame and the second lateral part makes it possible to attach the rib to the second upright of the frame.

By "partly curved" is meant that at least part of the shape of the central part is curved. In other words, a rib has its central part which is “partly curved” if the latter has in its central part only a curved part, or a plurality of curved parts, or even one or more straight ends when there is at least one main curved element.

In particular, the height, or longitudinal dimension measured along the longitudinal axis, of the central part is reduced relative to the longitudinal dimension of the first lateral part and / or the second lateral part.

The partly curved shape of the rib has an advantage during injection molding of the frame, the injected material being more easily distributed in a mold made of curves than in a mold having one or more angular parts, in particular at the junction of the rib and the first or second upright.

Furthermore, a rib comprising at least one curved part according to the invention does not fully cover any of the fins forming part of the radiant elements used to diffuse the heat. Thus, a greater number of fins at least partially allows the heat to be diffused to the air flow passing through the electric heating device. This optimizes the heat exchange between the air flow and the fins.

According to one aspect of the invention, the curve is an arc. In other words, the curved portion generates a C-profile of the rib. Thus, from one lateral end to the other of the rib, the curvature of the rib is continuous, which optimizes the resistance to effort of the rib, the ease of obtaining by molding as well as the clearance of each of the fins. forming radiant elements.

According to one aspect of the invention, the arc of a circle is configured so as to have a center arranged in a transverse plane passing through the longitudinal axis of the housing and perpendicular to the median longitudinal plane. The center of the arc is placed at an equal distance between the first upright and the second upright of the frame.

In particular, the circular arc described in the central part is symmetrical with respect to the transverse plane.

According to one aspect of the invention, the arc of a circle is configured so that the top of the curve is oriented towards the second longitudinal end of the frame. In other words, the apex of the curve being included in the central part, the apex of the curve is disposed at a greater distance from the first longitudinal end of the frame than are the first and the second lateral part respectively. In this way, when the heating element is inserted into its housing, the heating element passes first opposite the lateral parts of the rib and then opposite the central part and the top of the rib.

In an alternative example, the rib is curved opposite, with the top of the curve which is oriented towards the first longitudinal end of the frame.

According to one aspect of the invention, the first lateral part and the second lateral part of the rib are symmetrical with respect to the transverse plane. The first side part is then identical to the second side part. This symmetry is appreciated in the shape and dimensions of the first side part and the second side part. This symmetry is also appreciated in the arrangement of the first side part and the second side part by adding to the uprights of the frame carrying them respectively.

In this configuration, the first lateral part and the second lateral part are arranged at the same height, respectively on the first upright and the second upright. The height is considered along the extension axis of the housing: thus, the first lateral part and the second lateral part are at the same distance from the first longitudinal end of the frame.

According to one aspect of the invention, the first lateral part and the second lateral part each have a shape of paving stone comprising a first longitudinal end edge situated on the side of the first longitudinal end of the frame and a second opposite longitudinal end edge at the first edge and located on the side of the second longitudinal end of the frame, at least one of the first and second longitudinal end edges having a concavity. The concavity corresponds to a rounding formed between the first or the second upright and the central part of the rib. This concavity is located immediately around the amount concerned. This shape given to the first edge facilitates demolding of the frame when it is obtained.

One can in particular provide that at least one of the first and second longitudinal end edges has a concavity while the other is straight. The straight edge extends substantially perpendicular to the first or second wall.

More particularly, the first longitudinal end edge has a concavity when the curve is arranged so that its vertex is turned towards the first longitudinal end of the frame. And this is the second longitudinal end edge has a concavity when the curve is arranged so that its top is turned towards the second longitudinal end of the frame.

According to one aspect of the invention, the frame comprises a first longitudinal end of the frame intended for an operation of inserting the heating element into the housing, the first longitudinal end being opposite to a second longitudinal end of the frame, the rib comprising a leading edge turned towards the side of the first longitudinal end of the frame and an edge opposite the leading edge and turned towards the side of the second longitudinal end of the frame, the leading edge comprising a bevel forming a ramp inclined towards the housing of the heating element.

The first end of the frame is open on the housing to insert the heating element, during an assembly operation. The heating element is inserted into the housing in the direction given by the extension axis of the housing. The leading edge is the edge of the rib opposite which the heating element comes first when it is inserted. The leading edge is an edge of the rib which is likely to collide with the heating element being inserted.

The bevel can be located, at the leading edge of the rib, on the central part and / or on the first lateral part and / or on the second lateral part. Preferably, the bevel is at least found on the part of the leading edge intended to meet at first sight the heating element, that is to say the part of the rib closest to the first terminal end of the frame. . In particular, the bevel is found over the entire leading edge.

The bevel shape of the leading edge allows the heating element to slide on the rib during the insertion operation. The bevel forms a ramp which guides the heating element towards the inside of the housing, when it is inserted towards the second end of the frame.

According to one aspect of the invention, the frame comprises, on the same face of the frame and between the first upright and the second upright, the rib and an auxiliary rib joined in at least one junction portion. The rib and the auxiliary rib form a pair. The junction portion makes part of the rib coincident with a part of the auxiliary rib so that the rib and the auxiliary rib are indistinguishable at this junction portion.

According to one aspect of the invention, the auxiliary rib comprises an auxiliary central part, a third lateral part connected to the auxiliary central part and to the first upright of the frame, a fourth lateral part connected to the auxiliary central part and to the second upright of the frame. , the auxiliary central part forming at least part of a curve.

The curve of the auxiliary central part of the auxiliary rib is oriented in a direction opposite to the curve of the central part of the auxiliary jib rib. In other words, the rib has an apex facing the second longitudinal end of the frame and the auxiliary rib has an apex facing the first longitudinal end of the frame.

According to one aspect of the invention, the rib and the auxiliary rib both have a C-profile. In this configuration, with the rib and the auxiliary rib having a joint junction portion, the rib and the auxiliary rib are arranged back on back.

According to one aspect of the invention, the rib and the auxiliary rib are symmetrical with respect to a lateral plane perpendicular to the longitudinal plane and to the transverse plane. The lateral plane of symmetry passes through the junction portion and this results in an overall reinforcing element having a cross profile. This cross profile gives a certain flexibility to the twist to the pair of ribs and prevents them from breaking. In addition, efforts are better distributed there.

According to one aspect of the invention, the auxiliary rib has a first auxiliary border and a second straight auxiliary border. When inserting the heating element, it is first passed opposite the rib and then opposite the auxiliary rib. Therefore, it is not necessary that the auxiliary rib has a leading edge, unlike the rib as it could have been specified previously.

In the assembly formed by a rib and an additional rib, the leading edge of the rib is turned towards the side of the first longitudinal end of the frame and a border is opposite it. The leading edge of the rib has a bevel forming a ramp inclined towards the housing of the heating element. Furthermore, the auxiliary rib is such that the first right auxiliary border faces the first longitudinal end of the frame and the second right auxiliary border, opposite the first right auxiliary border, faces the second longitudinal end of the frame, at the opposite of the rib.

According to one aspect of the invention, the third lateral part and the fourth lateral part comprise a first edge and a second edge opposite the first edge, the first edge is closer to the arrow than the second edge, the first edge has a concavity and the second edge is straight. This concavity makes it possible to soften an angle formed by the first edge, and / or the second edge, and the arc of a circle when these are for example consecutive.

According to one aspect of the invention, the rib comprises an internal surface oriented towards the housing, the internal surface comprising a device for holding the heating element in position, projecting from the rib. The holding device is intended to interact with the heating element. 11 overcomes the vibrations of the frame, holding the heating element in position in its housing. Advantageously, the holding device is in contact with the heating element.

According to one aspect of the invention, the device for holding the heating element in position is carried by at least the central part of the rib. Advantageously, the device for holding in position is specifically arranged on the central part of the rib. For a pair of ribs, the holding device is arranged on the central part of the rib and / or on the auxiliary central part of the rib. In particular, the holding device is located on the junction portion. A centered position of the holding device, centered for example on the axis of extension of the housing, ensures a fair balance of the maintenance of the heating element.

According to one aspect of the invention, the device for holding the heating element in position has a bevelled face inclined towards the housing of the heating element. The holding device protruding from the internal surface of the rib, and therefore disposed in the housing, this beveled configuration allows the heating element to slide on the rib during an operation of inserting the heating element into housing.

The invention also relates to an electric heating device configured to heat a flow of air circulating in a vehicle ventilation, heating and / or air conditioning installation box, comprising it at least one frame as described above and a heating element housed in the housing of said frame.

The invention also relates to a ventilation, heating and / or air conditioning installation box for a vehicle, comprising an electric heating device as described above.

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

FIG. 1 is a general view of an air flow distribution assembly in which an electric heating device according to the invention is arranged,

FIG. 2 is a general perspective view of an electric heating device according to a first embodiment of the invention,

FIG. 3 is a detailed view of the frame of the heating device according to the first embodiment of the invention of FIG. 2, the frame being observed from inside the frame,

- Figure 4 is a detailed view similar to that of Figure 3> of a frame according to a second embodiment of the invention, this time seen from outside the frame.

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, transverse or lateral names, above, below, in front, behind, refer to the orientation of the heating element or of the frame of the electric heating device according to the invention. The longitudinal dimension is assessed along a longitudinal extension plane, called the median longitudinal plane A, and with respect to a longitudinal X axis of the housing formed in the frame, and it corresponds more particularly to the direction of elongation and insertion. heating elements in their housing provided as part of the electric heating device. The transverse and lateral orientations correspond to concurrent lines, that is to say which intersect the longitudinal dimension, in particular perpendicular to the longitudinal X axis of the housing. The transverse dimension corresponds in particular to the direction taken by a flow of air caused to pass through the frame according to the invention.

Furthermore, the designations "first", "second", "third", ... are not intended to establish a hierarchy or order for the terms they accompany. These designations are assigned on a distinctive basis, and can easily be exchanged without impacting the meaning of the description.

Referring first to FIG. 1, there is seen a set 14 of air flow distribution FA for vehicle. This assembly 14 comprises a housing 17 in which is housed an electric heating device 1. The electric heating device 1 comprises a frame here not visible and an electrical connection interface 31 fixed at the end of this frame and intended to be accessible when the electric heater is positioned in the assembly 14 for distributing air flow. The FA air flow distribution assembly 14 is intended for a vehicle ventilation, heating and / or air conditioning installation. 11 is intended to be traversed by an air flow FA inside the vehicle, represented by arrows, to heat treat this air flow and send it to the passenger compartment at an appropriate temperature for the comfort benefits desired by the 'user.

More particularly, the housing of the distribution assembly 14 comprises a body 24 with a structuring vocation, the external envelope of which includes air inlets and outlets cooperating with appropriate distribution ducts, not shown here.

The housing thus has an air inlet face of the distribution assembly 14, here not visible due to the angle of view, and two main portions 100 of air flow outlet FA. In the example illustrated, the housing and these main portions 100 are configured to form a six-zone assembly, that is to say capable of supplying heat-treated air to six distinct zones of the passenger compartment by means of duct connections. appropriate. This specific supply of six separate areas of the passenger compartment is illustrated schematically by the six arrows FA. Compartmentalization partitions are arranged in the air flow outlet portions to direct the air in the appropriate duct, the compartmentalization partitions can be associated, where appropriate, with compartmentalization flaps.

In order to allow the air flow to be oriented inside the box 17 of the air flow distribution assembly 14 FA so that it is correctly directed towards the desired outlet portion, the body 24 of the housing includes in its internal volume one or more walls which induce a distribution of the air flow FA, at least one of these walls being arranged in the context of the invention closest to the electric heating device.

This housing 17 includes a niche 5θ in which is housed the electric heating device 1 according to the invention. The niche 5θ has an opening on one of the faces of the housing ίο by which the electric heating device 1 according to the invention is inserted into the housing 17 during an insertion operation oriented along an insertion axis corresponding to an axis X of main longitudinal elongation of the electric heating device 1. The insertion operation is guided by the presence of the edges delimiting the opening defined by the recess, these edges guiding between them the frame of the electric heating device.

FIG. 2 illustrates the electric heating device 1 alone, so as to make visible curved ribs stiffening a frame structure of the device according to the invention.

The electric heating device 1 comprises a frame 3, made of two housings 4 in which are housed heating elements 2. The frame 3 has the shape of a rectangular parallelepiped having a median longitudinal plane A. The electric heater is configured to heat an air flow FA circulating transversely with respect to the median longitudinal plane A.

The heating elements 2 comprise radiant elements in particular formed of metal fins 35 in contact with electrodes enclosing resistive elements which take in particular the form of ceramic stones 6 PTC type and which generate heat under the effect of an electrical supply. electrodes, the heat being moreover diffused by the metal fins 35 · Each housing 4 extends along a longitudinal axis X inscribed in the median longitudinal plane A. The heating elements 2 are dimensioned so as to be able to be arranged in the housing 4 provided in the frame 3 ·

The frame 3 has two openwork faces 5 so as to allow the circulation of the air flow FA through the electric heating device 1. Each open face 5 thus opens onto the housings 4 so that the air flow FA passes through the elements heaters 2. When the air flow FA passes through the electric heating device 1 right through, entering through one face 5 and emerging from the other face 5 which is opposite to it, the heat diffused by the heating elements 2 is transmitted to the flow of air FA entering in contact with them and in contact with the radiant elements.

The frame 3 has a first longitudinal end 7 provided with an opening to allow the insertion of the heating elements 2 into the housing 4 and a second longitudinal end 8 opposite the first longitudinal end 7 · In this case, the heating elements 2 are already installed in their respective housings 4. The opening of the first longitudinal end 7 is here closed by a cover 9 integrating the electrical connection interface 31, the cover 9 being fitted on the first longitudinal end 7 of the frame. The second longitudinal end 8 closes the housings 4 by forming a bottom wall capable of holding the heating elements 2.

not

Each housing 4 is bordered laterally by a first upright 10 of the frame 3 and by a second upright 11 of the frame 3, the first upright 10 and the second upright 11 being substantially parallel to the longitudinal axis X.

Between the first upright 10 and the second upright 11, the frame 3 comprises at least one rib 12, 13 making it possible in particular to stiffen the perforated frame. More particularly, in the embodiment illustrated in Figures 2 and 3, the frame 3 has at least one rib 12 and an auxiliary rib 13, joined and organized in pairs. The auxiliary rib 13 is arranged in series longitudinally with the rib 12, so that the rib 12 and the auxiliary rib 13 are arranged one after the other along the longitudinal axis X. In the case illustrated in the figure 2, the frame 3 comprises several ribs 12 and auxiliary ribs 13, organized in pairs.

According to the invention, and as will be described in more detail with reference to FIG. 3, both of the ribs have at least in a central part a curved shape, and they can in particular have a single curvature for have a C shape.

The rib 12 and the auxiliary rib 13 participate, with the first upright 10 and the second upright 11, in delimiting the housing 4, the rib 12 and the auxiliary rib 13 participating in delimiting the housing in the transverse direction corresponding to the direction of LA air flow flow. The first upright 10 and the second upright 11 can also carry lugs 110 on which the heating elements 2 can bear, as can be seen in FIG. 4 · The lugs 110 project from the first upright 10 and the second upright 11 to form a stop for the heating elements across the perforated face 5.

The frame 3 also has two lateral ends 15 · A middle part 16 separates the housings 4 and contributes to the structure of the frame 3 · The first upright 10, the second upright 11, the ribs 12, the auxiliary ribs 13, the two ends side 15 and the middle part 16 are inseparable, so as to constitute a one-piece structure obtained for example by molding. The cover 9 is also an insert on the frame 3 ·

Figure 3 shows a detail of the electric heater 1 as illustrated in Figure 2, that is to say with a pair formed by a rib 12 and an auxiliary rib 13, seen from the inside of the housing 4 of the frame 3 · For the sake of readability of FIG. 3, the heating element or elements 2 normally present in the housing 4 have been removed.

The rib 12 comprises a central part 18, a first lateral part 19 connected to the first upright 10 of the frame 3 and a second lateral part 20 connected to the second upright 11 of the frame 3 · The first lateral part 19 and the second lateral part 20 are located in the same plane including the first upright 10 and the second upright 11, this plane being parallel to the median longitudinal plane A.

The rib 12 is characterized by its height, or longitudinal dimension, “h” defining the first lateral part 19 and the second lateral part 20 which is greater than the height, or longitudinal dimension, “H” defining the central part 18.

The rib 12 is delimited longitudinally by a leading edge 22 and a border 36, with the leading edge 22 facing the side of the first longitudinal end 7 of the frame and the edge 36 opposite the leading edge facing the side of the second longitudinal end 8 of the frame.

In this way, during the mounting operation during which the heating element 2 during its insertion into the housing 4 of the frame 3 borrows an insertion direction "S", the heating element 2 is brought to concomitantly meet the first lateral part 19 and the second lateral part 20, before the central part 18, the first lateral part 19 and the second lateral part 20 being closer to the first longitudinal end 7 than is the central part 18 due to the curved shape of the rib 12.

In the example illustrated, the leading edge 22 is bevelled while the border 36 is straight. Thus, during insertion, the heating element 2 can be guided towards the inside of the frame and of the housing corresponding to the contact of the ramp formed by the beveled leading edge. The edge 36 is not in direct contact with the heating element during its insertion, it is therefore not necessary to make a bevel on this edge.

The auxiliary rib 13 comprises an auxiliary central part 28 and a third lateral part 29 connected to the first upright 10 of the frame 3 · A fourth lateral part 3θ is connected to the second upright 11 of the frame 3 · The auxiliary rib 13 participates in the stiffening of the frame 3 without influencing the insertion of the heating element 2, unlike the rib 12. The auxiliary rib 13 has a first auxiliary border 37, straight, on the side of the first end 7 of the frame 3 and a second auxiliary border 38, right, on the side of the second longitudinal end 8 of the frame 3> opposite the first auxiliary border 37 ·

As mentioned above, the rib 12 and the auxiliary rib 13 have at least one curved part in their central part. More particularly, in the example illustrated, the central part 18 of the rib 12 describes an arc 43 whose apex 41 and center 44 are located in a transverse plane V passing through the longitudinal axis X of the housing and perpendicular to the longitudinal plane A median. The auxiliary central part 28 of the auxiliary rib 13 describes an auxiliary arc 46, the auxiliary apex 42 and the auxiliary center 45 of which are arranged in the transverse plane V.

The circular arc 43 and the auxiliary circular arc 46 having respective centers the center 44 and the auxiliary center 45 are arranged in opposite orientations so as to be symmetrical along a lateral plane B perpendicular to the transverse plane V and to the plane A longitudinal median. Thus, the rib 12 and the auxiliary rib 13 are symmetrical along this transverse plane B and along the plane V.

In the example illustrated in FIGS. 2 and 3, the central part 18 and the auxiliary central part 28 are C-shaped, the two Cs being inverted with respect to one another.

A portion of the central portion 18 merges with a portion of the auxiliary central portion 28. The meeting point of the rib 12 and the auxiliary rib 13 corresponds to a junction portion 26.

The first lateral part 19 and the second lateral part 20 of the rib 12 each have a block shape comprising a first edge 39 of longitudinal end situated on the side of the first longitudinal end of the frame and a second edge 40 of opposite longitudinal end at the first edge 39 and located on the side of the second longitudinal end of the frame. In the example illustrated, the curve is arranged so that its top is turned towards the second longitudinal end 8 of the frame. In this context, the first edge 39 is straight, that is to say perpendicular to the upright that the lateral part extends, while the second edge 40 is concave.

Similarly, the third lateral part 29 and the fourth lateral part 3θ each have a shape of paving stone comprising a third edge 47 of longitudinal end located on the side of the first longitudinal end of the frame and a fourth auxiliary edge 48 of longitudinal end opposite the first auxiliary edge and located on the side of the second longitudinal end of the frame. In the example illustrated, the curve is arranged so that its vertex is turned towards the first longitudinal end 7 of the frame. In this context, the third edge 47 is concave while the fourth edge 48 is straight.

In this way, in the example illustrated, the opposite edges of the lateral parts are both concave.

The rib 12 and the auxiliary rib 13 comprise, on an internal surface 51 oriented towards the housing 4, two devices 27 for holding the heating element 2 in position, which project from the rib 12 and the rib auxiliary 13 towards the heating element 2 when the latter is inserted into the frame. The two holding devices 27 are centered on the lateral plane B. In particular, these devices 27 for holding the heating element 2 in position are carried by the junction portion 26. They extend from the leading edge 22 to the second auxiliary edge 38. The device 27 of holding the heating element 2 in position has a first face 49, arranged in the extension of the leading edge 22, which is bevelled to complete the ramp towards the housing 4 of the heating element

2.

These devices 27 for holding the heating element 2 in position are intended to be in contact with the heating element 2. The presence of a holding device 27 is not limited to a frame 3 provided with rib 12 and rib auxiliary 13 · In another embodiment having only ribs 12 as will be described below, the devices 27 for holding in position are carried by a single rib 12, for example at its central part 18 .

The rib 12 and the auxiliary rib 13 are carried by one or the other of the faces 5 of the frame 3 · A pair of ribs 12, 13 of a face 5 is positioned alternately in the longitudinal direction relative to a another pair of ribs 12, 13 arranged on the other face 5, so that the lateral plane B of a pair formed by a rib 12 and an auxiliary rib 13 on one face 5 is distinct from the lateral plane B 'another pair of ribs 12 and auxiliary rib 13 carried by the other face 5 ·

Figure 4 illustrates a detail of frame 3 according to a second embodiment of the invention in which the uprights 10, 11 are reinforced by one or more ribs 12, arranged independently of the others without junction zone as it could be described with reference to the first embodiment. The frame 3 is here observed from the point of view of the exterior of the housing 4, revealing the heating element 2. The heating elements 2, arranged in the housing 4, in particular comprise metal fins 35 disposed in contact with electrodes enclosing resistive elements formed here by ceramic stones 6 with PTC effect.

The rib 12 is observed from outside the frame 3 · It corresponds to that described in FIG. 3, with the difference that the rib 12 is individualized, not being connected to an auxiliary rib 13 · It therefore does not include no junction portion. The rib 12 has symmetry only along the transverse plane V. In accordance with the above, the rib 12 has a curved part at least in its central part and here has a C shape.

FIG. 4 illustrates in particular an advantage of the invention according to which, due to the curved shape of the central part of the rib and the lateral dimension of the lateral parts connecting this central part to the uprights respectively delimiting the housings, none of the metal fins 35 forming part of the radiant elements is not completely covered by the rib. In other words, each fin is at least partially cleared so that air can pass through the electric heater, making each of the fins active. Thus, the heat exchange between the air flow FA and the heating elements is optimized because all the fins are operational, compared to a straight rib and perpendicular to the uprights as may be known from the prior art, which would conceal metallic fins in their entirety and render them non-operational.

It will be understood from reading the above that the present invention provides an electric heating device frame configured to facilitate the circulation of the air flow passing through it. This electric heating device frame, intended in particular to be integrated into a ventilation, heating, and / or air conditioning installation of motor vehicles, also makes it possible to propose a rigid electric heating device. Furthermore, the at least partially curved shape of the rib integrated into the frame, beyond its technical structural and energy advantages cited in this document, can allow rapid visual identification of the frame: it can thus be envisaged that the manufacturer of the frame gives the latter a distinctive silhouette that characterizes it.

The invention cannot however be limited to the means and configurations described and illustrated here, and it also extends to any equivalent means or configuration and to any technical combination operating such means. In particular, the shape of the electric heating device frame can be modified without harming the invention, insofar as the electric heating device frame for a vehicle, ultimately, fulfills the same functions as those described in this document.

Claims (10)

1. Frame (3) of an electric heating device (1) configured to heat an air flow (FA) circulating in a housing (17) for installing ventilation, heating and / or air conditioning of a vehicle, the frame (3) being configured to receive at least one heating element (2) in a housing (4) extending along a longitudinal axis (X), the housing (4) being bordered by a first upright (10) of the frame (3 ) and by a second upright (11) of the frame (3), the frame (3) comprising two faces (5) perforated at the level of the housing (4) and at least one rib (12) placed on one of the faces ( 5) openwork, the rib (12) comprising a central part (18), a first lateral part (19) connected to the central part (18) and to the first upright (10) of the frame (3), a second lateral part ( 20) connected to the central part (18) and to the second upright (11) of the frame (3), characterized in that the central part (18) forms at least partially a curve. 2. Frame (3) of an electric heating device (1) according to claim 1, in which the curve is an arc of a circle (43) · 3. Frame (3) of an electric heating device (1) according to the preceding claim, in which the arc of a circle (43) is configured so as to have a center (44) disposed in a transverse plane (V) passing through. the longitudinal X axis of the housing (4) and perpendicular to the median longitudinal plane A. 4. Frame (3) of an electric heating device (1) according to claim 2 or 3> in which the arc of a circle (43) is configured so that the top of the curve is oriented towards the second longitudinal end of the frame. 5. Frame (3) of an electric heating device (1) according to the preceding claim, in which the first lateral part (19) and the second lateral part (20) each have a shape of paving stone comprising a first edge (39) d the longitudinal end and a second longitudinal end edge (40) opposite the first edge, at least one of the first and second longitudinal end edges having a concavity. 6. Frame (3) of an electric heating device (1) according to any one of the preceding claims, in which the frame (3) has a first longitudinal end (7) of the frame (3) intended for an insertion operation. of the heating element (2) in the housing (4), the first longitudinal end (7) being opposite a second longitudinal end (8) of the frame (3), the rib (12) having a leading edge ( 22) turned towards the side of the first end (7) of the frame (3) and an edge (36) opposite the leading edge (22) and turned towards the side of the second longitudinal end (8) of the frame (3), the leading edge (22) having a bevel forming an inclined ramp towards the housing (4) of the heating element (2). 7. Frame (3) of an electric heating device (1) according to any one of the preceding claims, in which the frame (3) comprises, on the same face (5) of the frame (3) 5 and between the first upright (10) and the second upright (11), the rib (12) and an auxiliary rib (13) joined in at least one junction portion (26). 8. Frame (3) of an electric heating device (1) according to any one of the preceding claims, in which the rib (12) comprises an internal surface (51) oriented towards the housing (4), the internal surface (51 ) comprising a device (27) for holding in position 10 of the heating element (2), projecting from the rib (12). 9. Electric heating device (1) configured to heat an air flow (FA) circulating in a housing (17) for installing ventilation, heating and / or air conditioning of a vehicle, the electric heating device (1 ) comprising at least one frame (3) according to any one of the preceding claims and a heating element (2) housed in the housing (4) 15 of said frame (3). 10. Housing (17) for ventilation, heating and / or air conditioning installation for a vehicle, comprising an electric heating device (1) according to the preceding claim.