FR3078018A1 - FRAME FOR AN ELECTRIC HEATING DEVICE COMPRISING A PLASTIC DEFORMATION MEANS - Google Patents

Abstract

A frame (3) of an electric heating device comprises at least one housing (7) defined by longitudinal walls (23, 25) of the frame and intended to receive at least one heating element (5). At least one of the walls (23, 25) of the housing (7) comprises at least one plastic deformation means (10) configured to irreversibly deform the at least one heating element (5), said plastic deformation means ( 10) having a contact face (70) facing the interior of the housing, said contact face (70) being configured to include at least one recess (72).

Description

The invention relates to electric heating devices, in particular for a ventilation, heating 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 starts and for a certain period of time following the start time, the calories transported by the engine coolant are insufficient to ensure rapid and efficient heating of 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 electric heating device generally comprises a frame having a heating body comprising a plurality of parallel conductive plates between which are mounted resistive heating elements, for example resistors with positive temperature coefficient (PTC), and radiant elements increasing the heat exchange surface with the air flow passing through the heating device. These different elements are assembled so as to form at least one heating element, the heating element or elements constituting the heating body then being inserted in a housing thereof. To this end, the housing, defined by walls, comprises elastic elements, in particular arranged projecting from these walls, which are constrained during the insertion of the heating element (s) and which then exert an elastic restoring force participating in the plating. from the corresponding heating element to the opposite wall of the housing. This ensures that the heating element is kept in position in its housing, which must be provided with dimensions substantially larger than those of the heating element to allow its insertion.

The drawback associated with the use of these elastic elements exerting a restoring force on the heating elements lies in the fact that during rolling, or in the event of a fall of the heating device, the elastic elements are subjected to more or less vibrations. less important. These vibrations can cause noise in the ventilation circuit serving the passenger compartment, which can cause discomfort for users of the motor vehicle. It is also possible that these vibrations weaken or even break the elastic elements, the heating elements then no longer being held correctly in their housing.

In this context, the invention aims to propose an alternative to known frames of additional electric heating devices, which is at least as efficient, reliable, at a lower cost and simplified assembly.

To this end, the invention provides a framework 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 housing defined by longitudinal walls and intended to receive at least one heating element. According to the invention, at least one of the walls of the housing comprises at least one plastic deformation means configured to irreversibly deform the at least one heating element, and this plastic deformation means has a contact face facing the inside the housing, the contact face being configured so as to comprise at least one recess.

Thus, such a plastic deformation means allows the heating element to be pressed against the wall opposite to that on which it is located, by deformation of the heating element, which has the effect of keeping the heating element in the housing while by eliminating elastic elements capable of vibrating and generating noise inside the installation.

The plastic deformation means is distinguished from a guide rail by the fact that it is intended to irreversibly deform the heating element. In other words, the plastic deformation means arranged on one of the walls of the housing is located in the location intended to receive the heating element. More particularly, the deformation means is located in the path of the heating element when it is inserted into the housing.

The plastic deformation is for example a compression of the heating element.

The presence of the recess, without penalizing the guiding and the deformation of the heating element by the contact face, can make it possible, if necessary, to favor a deformation of the plastic deformation means rather than a deformation of the element. heating.

The frame of the electric heating device of an air flow according to the invention may further include one or more of the following characteristics, alone or in combination

- The recess extends from the contact face to the longitudinal wall on which the plastic deformation means extends.

- The recess is centered on the plastic deformation means, in the longitudinal direction of insertion of the heating elements in the housing and / or in the transverse direction of elongation of the corresponding longitudinal wall perpendicular to said longitudinal direction.

- The recess is a punctual recess. Advantageously, this point recess is arranged in the center of the contact face.

- The recess is linear and has an extension axis substantially perpendicular to the extension axis of the longitudinal walls. The recess thus has a form of slot, and this slot extends perpendicular to the direction of insertion of the heating elements in the housings.

- The recess has a triangular profile section. The point recess has the corresponding shape of the punch used to make this recess. Advantageously, the point recess has the shape of a point.

- The recess is bordered longitudinally by two projecting edges. In other words, the recess is arranged between a first upstream projecting edge and a second downstream projecting edge successively in contact with the heating element when it is inserted into the housing in the longitudinal direction.

- The recess extends over the entire width of the plastic deformation means. In this way, a flexibility is generated of the plastic deformation means which is homogeneous over the entire width, or transverse dimension, of the plastic deformation means.

- The plastic deformation means has a single recess. The recess can be positioned on the plastic deformation means to separate the latter into two symmetrical parts.

- The contact face of the plastic deformation means, intended to come into contact with the heating element, is a rounded face, the recess being produced at the top of this rounded face. By rounded face is meant a curved face, without edges. The deformation means is for example a boss.

- The plastic deformation means comprises a plurality of recesses, forming a plurality of protrusions between which each of the recesses extend respectively. Several of these protrusions can be configured so as to fit into a rounded envelope consisting of said contact face.

- The plastic deformation means is located on a median elongation axis of the at least one wall. The median elongation axis is defined as an axis extending over the length of the at least one wall and being located at an equal distance between two longitudinal edges defining a face of the wall, a longitudinal edge being defined as the edge of the wall extending along the longitudinal axis.

- The wall includes several means of plastic deformation.

- The walls defining the housing include at least a first longitudinal wall and a second longitudinal wall, said longitudinal walls being arranged facing one another, each longitudinal wall comprising at least one plastic deformation means.

- The plastic deformation means comes from material with the wall on which the plastic deformation means is located.

- The plastic deformation means extends from one longitudinal edge to the other of the wall on which the plastic deformation means is located. Thus, the plastic deformation means has a width identical to a width of the wall on which it is located.

The invention also relates to a heating device characterized in that it comprises a frame as defined above and comprising at least one heating element disposed in the housing of the frame, said at least one heating element being plastically deformed.

The device for electrically heating an air flow according to the invention may also include one or more of the following characteristics, alone or in combination:

- The plastic deformation means is located between a deformed lateral face of the heating element and a longitudinal wall defining the housing.

- The plastic deformation means is configured to compress the heating element in a plastic and irreversible manner towards the wall opposite the wall on which the plastic deformation means is located.

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 an overall perspective view of an electric heating device according to the invention, comprising a frame in which the heating elements have been inserted and at one end of which is fixed an electrical connection interface;

- Figure 2 is an enlargement of part of the frame of an electric heating device according to a first embodiment of the invention, here without the heating elements so as to make visible a first type of plastic deformation means fitted a longitudinal wall participating in forming the frame;

- Figure 3 is a view similar to that of Figure 2, illustrating an electric heating device frame according to a second embodiment; and

- Figures 4 and 5 are views in longitudinal section of two alternative embodiments.

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 alternative 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 they are arbitrarily defined by the trihedron L, V, T represented in the figures. The longitudinal axis L corresponds to the direction of elongation of the element in question. The choice of names for these axes is not limiting of the orientation that the device can take in its application to a motor vehicle.

The additional heating device according to the invention is capable of being 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 thermal energy returned in the air passing through this duct. 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 for the insertion of the additional heating device.

FIG. 1 shows an electric heating device 1 according to the invention, comprising a frame 3 into which heating elements 5, capable of transforming an electric current into thermal energy, have been inserted. To compensate for the manufacturing gaps existing between the heating elements 5 and the frame 3, the frame 3 comprises one or more plastic deformation means 10 which will be described later.

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 positive temperature coefficient (PTC), and against which the radiant elements 53 are fixed. The electrodes 54 and the PTC resistors make it possible to transform an electric current into thermal energy. It should be noted that the resistors with a positive temperature coefficient can be bonded directly to the radiant elements 53.

The frame 3 comprises a heating compartment 30, 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 into housings 7 formed inside the heating compartment 30, as visible in FIGS. 2 or 3. The connection interface 100 closes an opening 50 through which the heating elements 5 are inserted in the housings 7 of the heating compartment 30, at the same time as it allows the connection of the electric 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 transverse axis T, are perforated to allow the passage of an air flow 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 a 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.

It is also noted that the frame 3 includes bars 9 arranged, here, on the periphery of the heating compartment 30. These bars 9 participate in the stiffening of the frame 3 and include ventilation slots 90 allowing the air flow to circulate. through. The ventilation slots 90 are positioned one after the other along the longitudinal axis

L of the heating device 1, it being understood that the shape and the number of the air passages here formed by the slots is not limiting of the invention. 11 results from the arrangement on the periphery of the bars 9 that the housings 7 are placed side by side.

The heating compartment 30 includes a plurality of walls. Among these walls, there are longitudinal walls 23, 25 extending along the longitudinal axis L with two lateral longitudinal walls 23 and at least one intermediate longitudinal wall 25. The lateral longitudinal walls 23 define between them a vertical dimension of the compartment heater 30, and the intermediate longitudinal walls 25 extend parallel to the longitudinal side walls 23 and inside the heating compartment 30, so as to define, between them and with the longitudinal side walls 23, several housings 7 at the inside the heating compartment 30. Thus, each housing 7 of the frame 3 is delimited by walls. More specifically, each housing 7 is delimited vertically by two longitudinal walls 23, 25, which can be lateral 23 or intermediate 25. According to the illustrated embodiment, the frame 3 comprises two housings 7 with an intermediate longitudinal wall 25.

For each housing 7, a lateral longitudinal wall 23 and the intermediate longitudinal wall 25 delimit, between them and vertically, an insertion path for the heating element 5. The insertion path corresponds to the path taken by the heating element 5 when inserted inside the frame. The spacing between the longitudinal walls 23, 25 of the same housing 7 corresponds to the vertical dimension of the heating element 5, apart from the manufacturing clearance.

Each housing 7 is further delimited by a bottom wall 21 extending in a vertical transverse plane. This bottom wall 21 is located opposite the opening through which the heating elements 5 are inserted into the heating compartment 30. It should be noted that, according to the illustrated embodiment, the heating elements 5 are inserted in the housings 7 following an insertion direction parallel to the longitudinal axis L. The insertion direction S is defined from the opening towards the bottom wall 21.

The frame 3 also includes ribs 6 delimiting transversely the path for inserting the heating element 5 into the housing. For this, the ribs 6 extend at least between two longitudinal walls 23, 25 forming the same housing 7, and it should be noted that these ribs also have a role of stiffening the frame 3 and the heating compartment 30. The spacing between two ribs 6 located on either side of the insertion path along the transverse axis T corresponds to the transverse dimension of the heating element 5, apart from the manufacturing clearance.

According to the invention and in order to compensate for the manufacturing clearances between a heating element 5 and the walls delimiting the housing 7 receiving this heating element, the frame 3, and more particularly at least one longitudinal wall 23, 25 participating in defining a housing receiving a heating element, comprises at least one plastic deformation means 10 mentioned above and intended to irreversibly deform the heating element 5 when it is inserted into the corresponding housing.

For this, the plastic deformation means 10 projects from the longitudinal wall 23, 25 towards the inside of the heating compartment 30 so as to reduce the space allocated for the heating element 5 in the corresponding housing 7 and form a choke. 11 results from this that the heating element 5 is constrained during the passage at the level of this constriction and that the plastic deformation means 10 generates a plastic deformation of the heating element 5. More precisely, in order to generate this plastic deformation, the means deformation 10 has a rigidity greater than the rigidity of the heating element 5 and more particularly of the radiant element 53. Thus, it is ensured that only the heating element 5 is deformed while the plastic deformation means 10 and the walls longitudinal 23, 25 of the frame 3 remain intact.

The plastic and irreversible deformation of the heating element 5 when it is inserted into the housing 7 occurs when the heating element 5 finds itself constrained in its housing 7, under the effect of the contact of the heating element 5 with the means plastic deformation 10.

In the case of an insertion of the heating element 5 in the housing 7 along the longitudinal axis L, the plastic deformation results for example by a push in a vertical direction in the direction of the approach of the wall opposite to the wall bearing the plastic deformation means 10 acting on the heating element 5.

as a result, when the heating element 5 comes into contact with the opposite wall, compression of the heating element 5 and more precisely compression of the radiant element 53, in particular at the level of the plastic deformation means 10, this compression leading to local and irreversible plastic deformation of the radiant element 53.

It is understood that this irreversible deformation has the effect of keeping the heating element 5 in its housing 7 and of preventing any movement of the heating element.

FIG. 2 illustrates the frame without the heating elements, to make visible two plastic deformation means 10 respectively arranged in a housing defined by the frame, across a path for inserting a heating element brought to occupy this housing, and to make in particular visible a recess 72 formed according to the invention in each of these plastic deformation means.

Each plastic deformation means 10 projects from a longitudinal wall 23, 25, whether lateral or intermediate, by presenting a free end face intended to come into contact with the heating element 5. The face free end extends inside the housing 7 forming an obstacle to the insertion of a heating element 5 in the heating compartment 30.

Advantageously, at least one plastic deformation means 10 is in a region adjacent to the bottom wall, and in any case in the second longitudinal part of the frame, that is to say, relative to this longitudinal dimension, between a part central housing and the bottom wall. Provision may be made for this plastic deformation means disposed in an area adjacent to the bottom wall to be arranged at a longitudinal distance from the bottom wall of between 10 and 30 millimeters. In this way, the plastic deformation means is positioned at the end of the insertion stroke of the heating element, that is to say in the area where the heating element is most able to debate.

In terms of dimensioning, the plastic deformation means 10 may have a length, measured along the longitudinal axis L, which may for example be between 1 and 10mm.

The height of a plastic deformation means, the height being measured along the vertical axis V, can be of the order of 1 to 10% of the height of the housing in which it extends. Preferably, the height of the plastic deformation means, measured along the vertical axis V, is between 0.5 and 1.5 millimeters and more particularly between 1 and 1.5 millimeters, knowing that the manufacturing clearance between the heating element 5 and the housing 7 is generally between 0.2 millimeter and 0.5 millimeter.

it should be noted that in the case of a plurality of plastic deformation means on longitudinal walls defining the same housing, the sum of the heights of each of the plastic deformation means is taken into account, and in particular when these means are arranged in the same area of the housing, in order to ensure that the presence of the plastic deformation means does not generate a bottleneck which would increase the efforts of insertion of the heating elements.

it should be noted that the plastic deformation means 10 may extend partially or entirely from one longitudinal edge 36 to the opposite longitudinal edge, these two edges vertically delimiting the longitudinal wall 23, 25 on which the plastic deformation means 10 is located . In other words, the plastic deformation means 10 can have a width identical to the width of the longitudinal wall on which it is located, the width extending along the transverse axis T, as can be seen in FIG. 3.

It will be understood that the dimension of the plastic deformation of the heating element 5 depends on the dimensions of the plastic deformation means 10, it being understood that the larger the dimension of the plastic deformation, the better the heating element 5 is constrained in its housing 7 .

In what follows, we will define several different arrangements of plastic deformation means 10 equipping a frame 3 with an additional heating device 1 according to the invention. Each of these arrangements, which can differ in size, number and / or position of the plastic deformation means (s) 10, allows plastic deformation of a heating element 5 during its insertion to block it in a final position, without use of elastic deformation means.

A longitudinal wall 23, 25 can comprise a single plastic deformation means 10 or several plastic deformation means 10. In the embodiment illustrated in FIG. 2, two longitudinal walls each include a plastic deformation means 10, and these means plastic deformation are offset from each other longitudinally. Without departing from the context of the invention, provision may be made for one or more longitudinal walls to include one or more plastic deformation means

As shown in FIGS. 2 and 3, the plastic deformation means 10 is located on a median elongation axis M of the corresponding longitudinal wall 23, 25. The median elongation axis M is defined as an axis in which this wall 23, 25 extends longitudinally and being located equidistant from the two longitudinal edges 36 of this wall 23, 25. According to a variant of the plastic deformation means 10 located on the median axis M, it is possible to provide a plurality of plastic deformation means 10 arranged on either side of the median elongation axis M. It is understood that one seeks by this characteristic and its variant to achieve symmetrical deformation of the heating element inserted in the housing.

Furthermore, it should be noted, in the embodiment illustrated in FIG. 2, that the plastic deformation means have the same dimensions. Provision may be made for the plastic deformation means 10 of the same housing or of the same frame to have different dimensions between them.

Each plastic deformation means 10 has a free end face, forming a contact face 70 for the heating elements 5 inserted in the housing equipped with such a plastic deformation means. This contact face 70 is the face turned towards the inside of the housing 7, opposite the longitudinal wall. The contact face 70 here has a rounded shape, namely a curved face without edges. The deformation means 10 takes the form of a boss, for example.

The contact face 70 is configured so as to comprise at least one recess 72. The recess 72 is advantageously arranged at the top 71 of the plastic deformation means, that is to say at the top of the convex shape of the contact face 70.

In the embodiment illustrated in FIG. 2, the plastic deformation means 10 consists of a boss having the regular shape of a dome, and a single recess 72 is formed on this plastic deformation means, in this case arranged substantially at center of contact face 70.

The recess 72 is thus centered on the plastic deformation means 10, here longitudinally, that is to say in the longitudinal direction L of insertion of the heating elements in the housing, and transversely, that is to say in the transverse direction T of elongation of the corresponding longitudinal wall perpendicular to said longitudinal direction.

The recess 72 is in this embodiment a point recess, produced by punching the contact face. The shape of the recess thus corresponds to the male shape of the punch, and the recess here has a straight cylindrical bore, of vertical axis, perpendicular to the longitudinal wall forming a support for the plastic deformation means 10.

The recess 72 is delimited by a wall whose free end, at the level of the contact face, forms a protruding edge edge. In this case of a point recess, the projecting edge edge has a circular shape surrounding the recess. It can be noted that during its insertion into the housing, the heating element is caused to successively encounter a first portion of projecting edge 74, upstream of the recess, then a second portion of projecting edge 76, downstream of this recess. During insertion, the pushing force exerted on the heating element, as soon as it is in contact with the plastic deformation means in the housing, can generate a local deformation of the first protruding edge portion, which tends to disappear in the free space formed by the recess 72. In this way, the stresses undergone by the heating element in the narrowest area of the housing, that is to say in the area where the plastic deformation means is the most across the insertion path, can be decreased.

The depth of the recess 72 is obtained by the more or less long vertical insertion of the punch into the thickness of the plastic deformation means, it being understood that this recess may extend over the entire height, or over a height at least substantially equal to 10% of the height of the plastic deformation means, sufficient to generate the local deformability of the projecting edge bordering the recess.

We will now describe a second embodiment with reference to FIG. 3, in which the boss forming the plastic deformation means 10 has the shape of a portion of cylinder extending here from one longitudinal edge 36 to the other. of the corresponding longitudinal wall. Thus, the plastic deformation means has a width identical to a width of the wall on which it is located. The plastic deformation means thus participates in the deformation of the heating element over the entire width of the latter when it passes through the plastic deformation means.

The recess is, in this second embodiment, linear, so as to extend significantly over the transverse dimension of the plastic deformation means. The recess 72 has an elongation axis substantially perpendicular to the elongation axis of the longitudinal walls, and it thus has a form of slot which extends perpendicular to the direction of insertion of the heating elements in the housings. . In the example illustrated in FIG. 3, the recess extends over the entire width of the plastic deformation means. In this way, a flexibility is generated of the plastic deformation means, at the level of an edge edge delimiting the recess, which is uniform over the entire width, or transverse dimension, of the plastic deformation means.

In accordance with what has been described above, the plastic deformation means 10 comprises a single recess 72, again centered on the plastic deformation means in the longitudinal direction of insertion of the heating elements in the housing.

The recess 72 thus positioned on the plastic deformation means 10 makes it possible to separate the latter into two symmetrical parts, with, as has been described above, a first projecting edge 74 delimiting the recess upstream thereof, and a second projecting edge 76, delimiting the recess downstream thereof.

In the example illustrated, the recess 72 extends over the entire height of the plastic deformation means, from the contact face 70 to the longitudinal wall 23, 25 on which the plastic deformation means extends. And in accordance with what has been described above, the slot forming the recess takes the form of a rectangular section, obtained by appropriate right tools.

Of course, one could combine the teachings of the two embodiments described above without departing from the context of the invention, for example by providing one or more punctual recesses in the plastic deformation means in the form of a cylinder portion, since this combination helps to provide one or more recesses in the contact face of a plastic deformation means, in order to lighten the frame in which these elements are made and / or in order to allow local deformability of the deformation means plastic in an area of high stress for the heating element capable of being deformed by this plastic deformation means.

Other variants, described by way of nonlimiting examples, are illustrated in FIGS. 4 and 5, these variants having characteristics which can be combined with the characteristics of the embodiments previously described.

FIG. 4 represents a first alternative embodiment of the invention, in which the shape of the recess 72 is different, here having a triangular section instead of the rectangular section previously described. In other words, the point recess can have the shape of a point. In accordance with what has been described, the point recess has the corresponding shape of the punch used to make this recess.

this results in a more tapered shape of the projecting edges 74, 76 delimiting the recess upstream and downstream, and therefore a greater ability to local deformation under the effect of the passage of the heating element.

FIG. 5 represents a second alternative embodiment of the invention, in which the plastic deformation means this time comprises a plurality of recesses, forming a plurality of protrusions 78 between which each of the recesses extend respectively. Several of these protrusions can be configured so as to fit into a rounded envelope consisting of said contact face, here shown in dotted lines. Each recess 72 is delimited upstream and downstream by projecting edges 74, 76, and each upstream projecting edge 74 forming a protrusion inscribed in the envelope acting as contact face is liable to deform locally and to collapse at passage of the heating element 5.

In each of the embodiments and variants presented above, the plastic deformation means 10 can be provided by an insert, that is to say a part produced separately and then made integral with the corresponding longitudinal wall, or else may have come integrally with the longitudinal wall 23, 25 of the housing 7, in particular by a single molding operation.

Of course, a mixture of different shapes and / or different arrangements of the plastic deformation means 10 and of the recesses 72 for the same frame 3, or even the same longitudinal wall, is possible.

We will now describe the mounting of the additional heating device 1 comprising the frame 3 according to the invention, and in particular with reference to an embodiment in which the plastic deformation means conforms to what is illustrated in FIG. 2.

The heating elements 5 are firstly inserted into the appropriate housings 7 inside the heating compartment 30. For this, the heating elements 5 are inserted through the opening formed at one end of the frame 3, and the heating elements 5 are moved in translation towards the bottom wall 21 of the housing 7, in particular according to the direction of insertion shown by the arrow S.

During insertion, the heating element 5, and in particular the faces of the radiant elements 53 facing the longitudinal wall or walls carrying a plastic deformation means 10, comes into contact with these plastic deformation means 10. This heating element 5 is then deviated from its initial rectilinear trajectory, by being pushed in the direction of the longitudinal wall opposite to that on which the plastic deformation means are provided. Once in contact with the opposite longitudinal wall, the higher rigidity of the plastic deformation means 10 vis-à-vis the rigidity of the heating elements 5 makes it possible to plastically and irreversibly deform the heating element 5 inserted. The side face of this heating element 5 facing the plastic deformation means 10 undergoes compression in the direction of the longitudinal or intermediate wall opposite to that on which the deformation means 10 is located.

When the heating element 5 is in contact with the top 71 of the plastic deformation means 10, the compression is maximum because the space allocated for the passage of the heating element is minimal. 11 results in a maximum insertion force and it is expedient according to the invention that the recess 72 formed in the contact face 70 of the plastic deformation means allows local deformation, under the effect of contact with the heating element , of the projecting edge defining the upstream longitudinal edge of the recess. In this way, the deformation of the heating element is less and the insertion effort to be provided is less.

At the end of insertion, the heating elements 5 are constrained in their housing both by the plastic deformation means 10 and by the opposite wall, thus making it possible to avoid any existing play. The heating elements 5 do not debate inside their housing and therefore do not cause noise.

Finally, once the heating elements 5 have been inserted, the heating compartment 30 is closed by the connection interface 100. The connection interface is then placed at one end of the heating compartment 30 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 in which the heating elements do not debate inside their housing and therefore do not generate no noise likely to be heard by motor vehicle users, by means of a rigid plastic deformation means, which, moreover, is configured to allow relative flexibility in the contact zone causing the greatest stresses . The fact that the frame of the heating device comprises at least one such plastic deformation means ensures sufficient maintenance of the heating elements in their housing by eliminating any risk of deflection.

Claims (10)

1. Frame (3) of an electric heating device for a flow of air circulating inside a ventilation, heating, and / or air conditioning installation of a motor vehicle, said frame comprising at at least one housing (7) defined by longitudinal walls (23, 25) of the frame and intended to receive at least one heating element (5), characterized in that at least one of the walls (23, 25) of the housing (7) comprises at least one plastic deformation means (10) configured to irreversibly deform the at least one heating element (5), said plastic deformation means (10) having a contact face (70) turned towards the inside the housing, said contact face (70) being configured so as to comprise at least one recess (72). 2. Frame according to the preceding claim, characterized in that the recess is centered on the plastic deformation means (10), in the longitudinal direction of insertion of the heating elements in the housing (7). 3. Frame according to claim 1 or 2, characterized in that the recess (72) is a point recess. 4. Frame according to claim 1 or 2, characterized in that the recess (72) is linear and has an extension axis substantially perpendicular to the extension axis of the longitudinal walls (23, 25). 5. Frame according to one of the preceding claims, characterized in that the plastic deformation means (10) comprises a single recess (72). 6. Frame according to the preceding claim, characterized in that the contact face (70) of the plastic deformation means (10), intended to come into contact with the heating element (5), is a rounded face, the recess being made at the top (71) of this rounded face. 7. Frame according to one of claims 1 to 4, characterized in that the plastic deformation means (10) comprises a plurality of recesses (72), forming a plurality of protrusions (78) between which each extend respectively recesses. 8. Frame according to the preceding claim, characterized in that several of these protrusions (78) are configured so as to fit in a rounded envelope consisting of said contact face (70). 9. Frame according to any one of the preceding claims, characterized in that the plastic deformation means (10) came integrally with the wall (23, 25) on which it is located. 5 10. Heating device (1) characterized in that it comprises a frame (3) defined according to any one of the preceding claims and comprising at least one heating element (5) disposed in the housing (7) of the frame (3 ), said at least one heating element (5) being plastically deformed.