ELECTRONIC INTERFACE UNIT FOR AN ELECTRIC HEATING DEVICE OF A HEATING, VENTILATION AND / OR AIR CONDITIONING SYSTEM OF A MOTOR VEHICLE

Description

[0001] The technical field of the present invention is that of ventilation, heating and / or air conditioning of motor vehicles. The present invention relates more particularly to electric heating devices intended to be part of a ventilation, heating and / or air conditioning system of a motor vehicle.

[0002] The invention finds a particular application in an electric heating device, or electric heating system, comprising heating modules that diffuse heat under the influence of an electrical potential, i.e., resistive heating elements. These may be, for example, positive temperature coefficient (PTC) resistors, which allow for the rapid production of heat in vehicles when they are electrically powered.

[0003] Such electric radiators include, for example, a perforated frame configured to house heating modules as described above, so that these heating modules are in contact with an airflow passing through the frame. Such a frame comprises, for example, compartments receiving at least one heating module, which may consist of a tube containing electrodes surrounding resistive heating elements. Outside the tube, the electrodes extend into connection terminals, which in turn extend to connection terminals, themselves connected to a printed circuit board.The connection terminals, the printed circuit board, and other electronic components necessary for the operation of the electric heating device are integrated into an electronic interface box which includes a base receiving these components, and a cover which covers the base to protect them.

[0004] Document EP 3 310 127 A1 discloses a cover for an electronic interface housing of an electric heating device for a motor vehicle according to the preamble of claim 1.

[0005] The evolution of vehicle technologies and thermal requirements has led to the implementation of high-voltage electric heating devices. These devices use resistive elements to deliver sufficient heat to warm the air passing through the ventilation, heating, and / or air conditioning system without the need for an additional heat exchanger. These high-voltage devices require a greater number and larger electronic components, resulting in an increase in the size and volume of the electronic interface packages housing these components. This increased size and volume, in turn, leads to an increase in the size and, in particular, the surface area of ​​the package covers, making these covers more susceptible to deformation.

[0006] One problem with such devices lies in the rigidity of the electronic interface housing cover, which, due to its large surface area, is easily deformed under external mechanical stresses such as, for example, those resulting from vibrations induced by vehicle movement, or those occurring during the assembly of the electric heating device with the interlocking connection terminals. The present invention addresses this issue by seeking a simple solution for an electronic interface housing cover that is easy to assemble with a base for such a housing, sufficiently rigid to withstand the aforementioned stresses, and flexible enough to allow easy assembly with the aforementioned base without risk of damage to the electronic components housed within the enclosure.

[0007] To this end, the invention relates, according to a first aspect, to a cover for an electronic interface housing of an electric heating device for a motor vehicle, the cover comprising at least one support member and at least one support element respectively configured to be in contact with a printed circuit board when the cover is fixed to the electronic interface housing, a free end of the at least one support member extending in a first transverse plane and a free end of the at least one support element extending in a second transverse plane, the at least one support member and the at least one support element being arranged in projection, in a direction perpendicular to a reference plane of the cover, from an internal face of the cover intended to be turned towards the inside of the electronic interface housing,characterized in that the first transverse plane and the second transverse plane are substantially parallel to each other and to the reference plane of the lid, strictly not coinciding with each other and with the reference plane of the lid, the second transverse plane being, in a direction perpendicular to it, closer to the reference plane of the lid than the first transverse plane.

[0008] In one example, the cover according to the invention is made by injection molding a plastic material chosen for its thermal properties and its mechanical properties, including both flexibility and rigidity. Advantageously, the electronic interface housing to which the cover according to the invention is intended to be attached is also made by injection molding a plastic material. In various examples, the materials chosen for the cover and the electronic interface housing may be the same or different. The invention also applies without restriction in cases where all or part of the electronic interface housing is made of a metallic material formed from thin sheet metal, the mechanical properties of which, due to the thinness of the sheet metal used, are comparable to those of a plastic material.

[0009] According to an optional feature of the invention, the cover comprises a perimeter and a main wall that has a generally planar shape. The plane in which the main wall of the cover extends principally may, in particular, be designated as the reference plane of the cover. At least one support member and at least one bearing element project from an inner face of the cover, in a direction perpendicular to the aforementioned reference plane, and they are oriented such that, when the cover according to the invention is placed and fixed onto the previously mentioned electronic interface housing, they are directed towards the electronic components housed in the housing.

[0010] As previously mentioned, according to the invention, the first transverse plane and the second transverse plane, respectively defined by the free ends of the supporting members or elements, are substantially parallel to each other and to the reference plane of the cover, and strictly distinct from each other and from the reference plane of the cover. In other words, one of the previously defined transverse planes is, in a direction perpendicular to the reference plane of the cover, closer to the aforementioned reference plane than the other. That is to say, the free ends of at least one supporting member and at least one supporting element are offset from each other in a direction, also referred to as the axial direction, perpendicular to the reference plane of the cover.

[0011] In other words, a dimension, measured along the aforementioned axial direction, that is to say perpendicular to the reference plane of the cover, of one of the support means, namely at least one support member or at least one support element, is less than the dimension, measured along the same axial direction, of the other support means.

[0012] It follows from the foregoing that a slight gap exists, when the cover according to the invention is placed on the electronic interface housing, between at least one support element and the printed circuit board with which this support element is intended to be in contact once the cover is fixed to the electronic interface housing. It should be understood here that this gap is sized so that, when the cover is fixed to the housing, at least one support element is indeed in contact with the aforementioned printed circuit board. For example, this gap, or offset, measured along the aforementioned axial direction, that is, perpendicular to the reference plane, between the first transverse plane and the second transverse plane, is on the order of 1 to a few tenths of a millimeter. Preferably, but not exclusively, this offset is less than 0.5 millimeters.It should be noted that the direction perpendicular to the reference plane of the cover, or axial direction, is also the direction of placement of the cover on the electronic interface housing.

[0013] Depending on various characteristics, taken separately or in combination: The cover includes elastic fastening means for snapping onto a base of the electronic interface housing, and at least one support element is located between a support member and an edge of the cover on which elastic fastening means are arranged. This at least one support element comprises a plurality of pins arranged projecting from the inner face of the cover, perpendicular to its reference plane. Advantageously, the pins are all identical, for example, cylindrical. The second transverse plane mentioned previously is therefore defined by the free ends of all these pins. The pins of the at least one support element are arranged in a staggered pattern along at least two transverse lines.More specifically, according to this feature, the bases of the pins of the support element, by which said pins are attached to the inner face of the cover according to the invention, are arranged on this inner face in at least two substantially parallel lines. Furthermore, according to this feature, the aforementioned pins are staggered along the two aforementioned transverse lines. Such a surface arrangement of the pins constituting at least one support element allows for a precise definition of the second transverse plane described above. Moreover, in an electronic interface housing equipped with a cover according to the invention, such an arrangement of the pins localizes the play, or offset, mentioned above, across the entire surface of the region of the cover in which the pins are arranged.The aforementioned clearance thus becomes a surface clearance, allowing the snap-fit ​​force to be distributed across the entire surface of the lid region in which the pins extend. In a case where the pins of the support element are arranged in a region of the lid intended to cover a printed circuit board housed in the electronic interface enclosure, this protects the electronic components from excessive stress and damage during assembly of the lid with the electronic interface enclosure. The pins constituting at least one support element are arranged protruding from a deformed area of ​​the lid's inner face.Advantageously, the deformation of this area, when the cover is attached to the electronic interface housing, is directed inwards towards the housing itself, that is, towards the electronic components housed within it, and in particular towards the printed circuit board mentioned earlier. For example, this deformed area, viewed from the outer face of the cover, opposite its inner face in a direction perpendicular to its reference plane, forms a recessed cup shape within the electronic interface housing when the cover is attached. The resulting shape of the deformed area provides additional support for the cover, supplementing the at least one component and at least one support element mentioned previously.More specifically, the presence of such a deformed zone makes it possible, in particular, to reduce or even eliminate any risk of deformation of the cover under the effect of vibrations and / or stresses resulting from the vehicle's movement or induced by the assembly of the electric heating device. At least one support member includes at least one rib substantially perpendicular to the first transverse plane. For example, at least one support member includes a first portion, for example substantially cylindrical, and a second portion extending from the first portion, forming a substantially flat rib whose plane contains the axis of the first substantially cylindrical portion.In one example, the aforementioned rib extends from the inner face of the lid, and one dimension of this rib, measured perpendicular to the lid's reference plane, is substantially equal to the dimension, measured in the same direction, of the first portion of the at least one support member. It follows that the first transverse plane is defined by both the free end of the first portion of the at least one support member and the axial dimension of the aforementioned rib. It should therefore be noted that, in such a configuration, the first transverse plane is defined by the free end of a single support member, while the second transverse plane is defined by the free ends of a plurality of supports. Alternatively, the at least one support member may have a first rib and a second rib extending symmetrically on either side of the first portion of the support member.As an example, the cover includes several support elements of one and / or the other type mentioned above.

[0014] The invention thus achieves its intended purpose by proposing, through simple solutions, a cover for an electronic interface box of an electric heating device in a ventilation, heating and / or air conditioning system for a motor vehicle, a cover which has, on the one hand, sufficient rigidity to resist, in particular, the vibrations and stresses induced by the movement of the vehicle, and, on the other hand, sufficient flexibility to allow its attachment to the electronic interface box without risk of damage to the electronic components housed in this box under the effect of the stresses exerted during the installation of the cover.

[0015] According to a second aspect, the invention extends to an electronic interface housing for an electric heating device for a motor vehicle, comprising a cover as described above, and a base configured to house a printed circuit board, the base comprising snap-fit ​​means configured to cooperate with elastic fastening means carried by the cover in order to close a receiving cavity for the printed circuit board.

[0016] Advantageously, snap-on means carried by the base are configured to cooperate with elastic fastening means, carried by the cover, located near at least one support element previously mentioned.

[0017] According to an advantageous feature of the invention, such an electronic interface housing includes an electrical connection area and a connection area to heating elements of an electric heating device of the motor vehicle, and at least one support element of the cover is located near the connection area to the heating elements of the electric heating device.

[0018] As previously mentioned, the invention finds a privileged application in an electric heating device comprising at least one heating module formed of a tube inside which are housed electrodes which surround resistive heating elements, and in which the electrodes are extended, outside the tube, by connection terminals which extend to connection terminals themselves connected to the previously mentioned printed circuit board, placed in the electronic interface box.In addition to the area for connecting the printed circuit board to the electrodes of the heating elements, such a housing also includes an electrical connection area through which the printed circuit board is connected to a power supply device, for example a power supply device specific to the ventilation, heating and / or air conditioning system, or a vehicle power supply device.

[0019] It follows from the above that the area where the heating elements connect to the electrodes is mechanically the most fragile. Positioning at least one support element of the cover near this area therefore protects this part of the electronic interface housing through the clearance defined and described above. The stress exerted on the connection area to the heating elements during the installation and securing of the cover to the housing base according to the invention is thus reduced, thereby preventing any stress and damage to the connection elements in this region.

[0020] Advantageously, in the electronic interface housing according to the invention, the printed circuit board is sandwiched between at least one support member of the cover and a reinforcing element arranged in the base. It should be understood here that the reinforcing element is arranged perpendicular to the reference plane of the cover, and that the sandwiching occurs once the cover is in place and secured, by the previously mentioned elastic snap-fit ​​fastening means, to the base of the housing. This notably ensures that the printed circuit board remains securely in place and minimizes any vibrations it might exhibit while the vehicle is in motion.

[0021] The invention finally extends to an electric heating device for heating an airflow in a motor vehicle, comprising at least one heating element and an electronic interface housing as previously described.

[0022] Other features and advantages of the present invention will become more apparent from the description and drawings, including: [ Fig 1 ] schematically illustrates in perspective an electric heating device intended for a ventilation, heating and / or air conditioning system in a motor vehicle, [ Fig 2 ] is a schematic perspective view of a cover of an electronic interface housing according to a first aspect of the invention, viewed from the side of its inner face, intended to be turned towards the interior of the electronic interface housing of an electric heating device such as that illustrated by the figure 1 , [ Fig 3 ] is a partial representation, in cross-section along a plane perpendicular to its reference plane, of a lid and a housing such as those illustrated by the figure 2 , [ Fig 4 ] schematically illustrates, in cross-section along a plane perpendicular to the reference plane of the cover, the installation and fixing of a cover on an electronic interface housing such as those illustrated by the figure 3 , there figure 4 illustrating more specifically the electronic interface housing and the front cover, which is elastically secured by snap-fit, [ Fig 5 ] is a view similar to that of the figure 4 illustrating more specifically the electronic interface housing and the cover once the cover is fixed by snapping it onto a base of the housing.

[0023] It should first be noted that while the figures illustrate the invention in detail for its implementation, they can, of course, also serve to further define the invention where necessary. It should also be noted that these figures only show some of the possible embodiments of the invention.

[0024] With reference to the figure 1 An electric heating device 100 suitable for equipping a ventilation, heating and / or air conditioning system of a motor vehicle includes, in particular, a frame 1 in which several heating elements 2 are arranged, the role of which is to heat an airflow passing through the frame 1. The direction of such an airflow is represented by the arrow F on the figure 1 The electric heating device 100 also includes an electronic interface box 300 configured to house all the electronic components which both supply power to the electric heating device 100 and control its operation.

[0025] According to the example most particularly illustrated by the figure 1 The frame 1 is substantially in the shape of a rectangular parallelepiped, the longest dimension of which extends along a longitudinal direction L of the electric heating device 100. More precisely, the frame 1 consists of two substantially flat side walls, 10a and 10b respectively, substantially parallel to each other, within manufacturing tolerances, and a substantially flat bottom wall 10c perpendicular to the side walls 10a and 10b. The side walls 10a and 10b and the bottom wall 10c together form a U-shape, with the bottom wall 10c forming the base, and together they define a housing 150 for the heating elements 2. As shown in the figure 1 The side walls 10a, 10b of frame 1 extend mainly along the previously mentioned longitudinal direction L, and the bottom wall 10c, substantially perpendicular to the side walls 10a, 10b, extends mainly along a transverse direction T of the electric heating device 100, the transverse direction T being perpendicular to the previously defined longitudinal direction L. The walls 10a, 10b, 10c also extend, perpendicular to the longitudinal direction L and the transverse direction T, along a vertical direction V of the electric heating device 100, such that the directions L, T, V together form a right-handed trihedron. It should be noted that the vertical direction V is also, as shown in the figure 1 , the direction of passage of an airflow to be heated in the electric heating device 100. It should also be noted that the aforementioned longitudinal, transverse, and vertical directions may, in a motor vehicle equipped with an electric heating device 100, have any orientations with respect to the longitudinal, transverse, and vertical directions of the vehicle in question.

[0026] With reference to the directions and orientations defined above, the electronic interface housing 300 is placed at the longitudinal end of the frame 1 opposite the bottom wall 10c of the latter, so as to close the opening of the U formed by the walls 10a, 10b, 10c, of the frame 1 when assembling the electric heating device 100.

[0027] In the housing 150, delimited in particular by the walls 10a, 10b, 10c of the frame 1, each heating element 2 extends substantially parallel to the lateral walls 10a, 10b, of the frame 1, that is to say substantially parallel to the longitudinal direction L of the electric heating device 100. Each heating element 2 therefore has, according to the longitudinal direction L of the electric heating device 100, a first end 20 located near the bottom wall 10c of the frame 1 and a second end 21 located near the electronic interface box 300.

[0028] It should be noted that the electric heating device, according to the invention, could be implemented without a frame, which has been described herein as a structural element that serves, in particular, to protect the heating elements and facilitate the integration of the electric heating device into the ventilation, heating, and air conditioning system, notably for reasons of device weight reduction. In such a context, the heating elements remain attached to the electronic interface housing and are subject to airflow, and the structure of the electronic interface housing remains unchanged from what follows.

[0029] The electronic interface housing 300 comprises a base 3 and a cover 4. The base 3 is configured to house electronic components for powering and controlling the operation of the heating elements, and the cover 4 is configured to cover an opening in the base 3 to protect the aforementioned electronic components. These electronic components include, in particular, a printed circuit board 5, not visible in the figure 1 , configured to command and control the operation of the heating elements 2. The base 3 therefore forms a cavity 35, not marked on the figure 1 , receiving the aforementioned electronic components and, in particular, the printed circuit board 5.

[0030] As shown by figure 1 , the base 3 includes fixing elements 30 allowing the heating device 100 to be fixed in a casing of a ventilation, heating and / or air conditioning system of a motor vehicle.

[0031] The base 3 here has the general shape of a T, comprising a first part 31 and a second part 32, one dimension of which, along the transverse direction T of the electric heating device 100, is greater than a transverse dimension of the first part 31. The second part 32 of the base 3 lies, along the longitudinal direction L of the electric heating device 100, in line with the heating elements, and the first part 31 of the base 3 lies, along the vertical direction V of the electric heating device 100, in line with the second part 32. Along the aforementioned transverse direction T, the first part 31 and the second part 32 of the base 3 are substantially centered with respect to each other. The receiving cavity 35 mentioned previously extends advantageously into the first part 31 and the second part 32 of the base 3.

[0032] The cover 4 is located opposite, along the longitudinal direction L of the electric heating device 100, the portion by which the electronic interface housing 300, and more specifically its base 3, is connected to the heating elements. The cover 4 has a substantially flat main wall 40, which extends primarily along a plane 400 defined by the transverse direction T and the vertical direction V of the electric heating device 100. This plane 400 will be referred to hereafter as the reference plane of the cover 4.

[0033] With reference to the figure 1 The cover 4 has a T-shape complementary to that of the base 3, comprising a first part 41, whose shape and dimensions are complementary to the shape and dimensions, in projection onto the reference plane 400, of the first part 31 of the base 3, and a second part 42, whose shape and dimensions are complementary to the shape and dimensions, in projection onto the reference plane 400, of the second part 32 of the base 3. More precisely, the shapes and dimensions of the first part 41 and the second part 42 of the cover 4 are defined such that the cover 4, when fixed onto the base 3, completely covers and seals the opening of the receiving cavity 35 previously defined. According to the example more particularly illustrated by the figure 1 , the receiving cavity 35 extends substantially over the entire base 3, the cover 4 covering the latter.

[0034] The base 3 and the cover 4 also include means for elastically snapping the cover 4 onto the base 3. According to the example more particularly illustrated by the figure 1 These means include, in particular, on the one hand, at least one lug 33 projecting from a wall of the base 3 and, on the other hand, additional means 43 projecting from the perimeter of the cover 4. According to the example more particularly illustrated by the figure 1 Several lugs 33 are distributed on the lateral walls of the base 3. In particular, a lug 33 is arranged on each lateral wall 320, substantially parallel to a vertical longitudinal plane 410, of the second part 32 of the base 3. According to the example more particularly illustrated by the figure 1 , lugs 33 are also arranged on a longitudinal wall 321 of the second part 32 of the base 3, perpendicular to the aforementioned lateral walls 320, as well as on a longitudinal wall 310 of the first part 31 of the base 3. Advantageously, the cover 4 has as many elastic snap-fit ​​fastening means 43 as the base 3 has lugs 33.

[0035] There figure 2 shows more specifically the cover 4 of an electric heating device 100 such as the one illustrated by the figure 1 , seen from the inside of it, that is to say seen from the side of it intended to be placed opposite the receiving cavity 35 when the cover 4 is fixed on the base 3. As a reminder, the receiving cavity 35 is configured to receive the electronic components for the control and monitoring of the operation of the heating elements 20 of the electric heating device 100.

[0036] We find on the figure 2 the reference plane 400 of the lid 4, previously defined, as well as the main wall 40, the first part 41 and the second part 42 of the lid 4. We also find on the figure 2 the trihedron (L, V, T), previously defined, of the electric heating device 100 as illustrated by the figure 1 , the side walls 420, previously mentioned, of the second part 42 of the cover 4, as well as the elastic snap-fit ​​fastening means 43 complementary to the lugs 33 previously described. These means 43 here take the form of eyelets pierced with an opening configured to cooperate with the lugs. According to the example illustrated by the figure 2 , the cover 4 includes in particular several elastic snap-fit ​​fastening means 430 located on the side walls 420 of the second part 42 of the cover 4.

[0037] According to the example most particularly illustrated by the figure 2 , the cover 4 comprises, extending in projection from the inner face 401 of its main wall 40, a first support member 44a, arranged in the first part 41 of the cover 4, and a second support member 44b, arranged in the second part 42 of the cover 4.

[0038] The first support member 44a and the second support member 44b extend from the inner face 401 of the main wall 40 of the cover 4 substantially perpendicular to the reference plane 400 of the cover 4. More precisely, the first support member 44a and the second support member 44b are attached to the inner face 401 of the cover 4 by one of their ends along the longitudinal direction L, and their opposite end, along said longitudinal direction L, is free. The support members 44a and 44b therefore extend towards the interior of the electronic interface housing 300 when the cover is attached to the base of the electronic interface housing.

[0039] According to the invention, the free ends of the first support member 44a and the second support member 44b together define a first transverse plane 451, substantially parallel to the vertical direction V and the transverse direction T of the cover 4 and the electric heating device 100, and notably visible on the figure 3 . The first transverse plane 451 is therefore, within manufacturing tolerances, substantially parallel to the reference plane 400 of the cover 4.

[0040] According to the example most particularly illustrated by the figure 2 The first support member 44a comprises a first portion 440a, substantially cylindrical, whose axis is, within manufacturing tolerances, substantially perpendicular to the datum plane 400, and a second portion 441a, substantially flat, forming a rib extending from the aforementioned first portion 440a. More precisely, the second portion 441a extends along a plane perpendicular to the datum plane 400 containing the axis of the first portion 440a. According to the example illustrated by the figure 2 , non-exclusive, the second portion 441a of the first support member 44a extends along a plane substantially parallel to a vertical longitudinal plane defined by the longitudinal directions L and vertical directions V of the electric heating device 100.

[0041] According to the example most particularly illustrated by the figure 2 , the second support member 44b comprises, like the first support member, a first portion 440b, substantially cylindrical, whose axis is, within manufacturing tolerances, substantially perpendicular to the reference plane 400. Advantageously, a dimension, measured perpendicular to the reference plane 400, of the first portion 440b of the second support member 44b, is identical to a dimension, measured along the same direction, of the first portion 440a, of the first support member 44a.

[0042] The second support member 44b also includes a second substantially flat portion extending from the aforementioned first portion 440b. This second portion of the second support member 44b extends along a plane containing the longitudinal axis of the first portion 440b, and it takes the form of two ribs 4410b, 4411b diametrically opposed to the aforementioned first portion 440b, extending along a transverse longitudinal plane defined by the longitudinal direction L and the transverse direction T of the electric heating device 100. It should be noted that these two ribs of the second support member 44b are arranged perpendicularly to the second portion 441a of the first support member 44a.

[0043] It was previously stated that the free ends of the first support member 44a and the second support member 44b together define a first transverse plane 451, substantially parallel to the reference plane 400 of the cover 4. This first transverse plane 451 is defined by the free ends of the ribs 441a, 4410b, 4411b, that is, by their longitudinal dimension. According to the example illustrated by the figure 2 , the longitudinal dimensions, measured perpendicular to the reference plane 400 of the cover 4, of the ribs of each support member are identical, and here they are slightly greater than the corresponding dimensions of the first portions of each support member.

[0044] The lid 4 also includes a support element 405, which here takes the form of a plurality of pins 45 projecting from the inner face 401 of its main wall 40. As shown in the figure 2 The pins 45 extend from the previously defined inner face 401 of the cover 4 in a direction substantially perpendicular to the reference plane 400 of the latter. In other words, like the support members 44a, 44b, the pins 45 extend towards the interior of the electronic interface housing 300.

[0045] The pawns 45 are arranged here in the second part 42 of the lid 4. According to the example illustrated by the figure 2 , the pins 45 are substantially cylindrical, with an axis perpendicular to the reference plane 400. Each pin 45 thus has, along a longitudinal direction perpendicular to the reference plane 400, a first end 4500 by which it is attached to the inner face 401 of the cover 4, and a second end 4501, free.

[0046] According to the invention, the free ends 4501 of the pins 45 together define a second transverse plane 452, parallel to the reference plane 400, and not coinciding with it. To this end, the longitudinal dimensions, measured perpendicular to the reference plane 400, of the pins 45 are all identical. More particularly, and as will be particularly evident on the figure 3 , the second transverse plane 452 is closer to the reference plane 400 than is the first transverse plane 451.

[0047] According to the example illustrated by the figure 2 , the pins 45 are arranged in projection from a deformed area 402 of the main wall 40 of the cover 4. More precisely, the deformed area 402 constitutes a bowl shape whose bottom 4020, substantially parallel to the reference plane 400 of the cover 4, extends offset, along the longitudinal direction L, from the inner face 401 of the cover 4, towards the interior of the electronic interface housing 300.

[0048] This deformed zone 402 extends, in the second part 42 of the cover 4, in the vicinity of the elastic snap-fit ​​fastening means 430 arranged on the side walls 420 of this second part. As a result, the pins 45 are also located in the vicinity of these elastic fastening means 430, and in particular between these elastic fastening means 430 and the second support member 44b.

[0049] According to the example illustrated by the figure 2 The pins 45 are distributed along two parallel lines 455 and 456, staggered relative to each other along these two lines. Furthermore, the pins 45 are arranged here approximately across the entire base 4020 of the deformed zone 402, parallel to the reference plane 400 of the cover 4.

[0050] There figure 3 shows a detail of the electronic interface housing 300, in a position in which the cover 4 is placed, but not fixed, on the base 3. This detail makes visible on the one hand the deformed area 402 and the studs 45 of the support element as previously described and on the other hand the second support member 44b, its first portion 440b and one of its ribs 4410b, 4411b.

[0051] More specifically, the figure 3 makes visible a pin 45 of the line 455 of pins previously described, as well as, at the level of the other line 456, the end of a connection terminal 50 of a heating element suitable for cooperating with an electrode 22 of this heating element, the pins 45 being arranged in a staggered fashion from one line to the other.

[0052] According to the invention, the support members 44a, 44b and the pins 45 are in contact with the printed circuit board 5 when the cover 4 is fixed on the base 3 of the electronic interface housing 300, by cooperation of the snap-on fastening means carried by the cover and the base.

[0053] There figure 3 It becomes apparent that, before the cover is fixed to the base, when the cover is positioned opposite the base, rib 4410b, 4411b, and more generally each of the ribs of the support members, is in contact with the printed circuit board 5, while pin 45, and more generally each of the pins, is not in contact with the printed circuit board. More specifically, the invention provides that, in the position in which the cover 4 is placed on the base 3 of the electronic interface housing 300, but not fixed to it, the first transverse plane 451 and the second transverse plane 452, previously described, are, in a direction perpendicular to the reference plane 400, offset longitudinally from each other and from the reference plane 400.The longitudinal offset between the first transverse plane 451 and the second transverse plane 452 is on the order of 1 to a few tenths of a millimeter, and preferably less than 5 tenths of a millimeter. This offset results in play for the attachment of the cover 4 and thus gives the latter a certain degree of flexibility in the region where the pins 45 are arranged.

[0054] It then follows from the arrangement of the pins 45 in the second part 42 of the cover 4, that is to say in the part of this cover intended to cover the region of the electronic interface housing 300 in which is located the area of ​​connection to the heating elements of the electric heating device 100, that this makes it possible to avoid any excessive stress on the connection terminals 50 and the corresponding electrodes 22 when fixing the cover on the base.

[0055] The play in assembly, permitted by the axial offset of the free ends of the ribs and studs as previously described, is made over the entire surface of the region in which the pins 45 are arranged, that is to say, according to the example illustrated by the figures, over the entire surface of the bottom 4020 of the deformed area 402. This allows a better distribution of the fixing force of the cover in this region.

[0056] We also notice on the figure 3 that the printed circuit board 5 is sandwiched between the rib 4410b, 4411b of the second support member 44b and a stud 34 of the base 3. This makes it possible in particular to ensure good retention of the printed circuit board 5 in the electronic interface housing 300, reducing the effect of vibrations which may result from the driving of the vehicle equipped with the electric heating device 100, as well as during the placement and fixing of the cover 4 on the base 3.

[0057] What has just been described with reference to the figure 3 is illustrated schematically on the figure 4 , namely a representation of the electronic interface housing 300 in a position in which the cover 4 is placed on the base 3, but not fixed to the latter, and the figure 5 illustrates the same electronic interface housing 300 this time in a position in which the cover 4 is fixed on the aforementioned base 3.

[0058] We thus find, on these figures 4 et 5 , the cover 4, its reference plane 400, the deformed area 402 and its bottom 4020, a support member 44a, 44b, as well as a pin 45 and the stud 34 previously described. These figures also schematically show a lug 33 arranged projecting from a lateral wall 320, 321, of the second part 32 of the base 3, as well as an eyelet 430 forming an elastic snap-fit ​​fastening means in the second part 42 of the cover 4. It should be noted here that, while the support member 44b schematically mentioned here may be of the type of the second support member 44b previously described with two ribs 4410b, 4411b, it may also be of the type of the first support member 44a with a single rib 441a, the support member illustrated in figures 4a and 4b being the one that is closest to the pins 45 arranged in the second part 42 of the cover 4.

[0059] As shown by figure 4 , in the position in which the cover 4 is placed on the base 3 but not fixed to it, the first transverse plane 451 and the second transverse plane 452 are offset from each other along a longitudinal direction perpendicular to the reference plane 400 of the cover 4. The ribs of the support members are in contact with the printed circuit board 5 so that the longitudinal offset mentioned above implies a clearance 500 between on the one hand the printed circuit board 5 and the first transverse plane 451 and on the other hand the free end 4501 of the pins 45 and the second transverse plane 452.

[0060] It is understood that in order to engage the eyelets 430 with the lugs 33 to achieve the snap-fit ​​fastening of the cover 4 onto the base 3, it is necessary to exert a force on the cover 4 directed perpendicularly to the aforementioned reference plane 400, a force whose direction is represented by the arrow F1 on the figure 4 .

[0061] The presence of the 500 set makes it possible in particular to ensure the correct engagement of the snap-fit ​​fastening means despite the manufacturing and assembly clearances of the components of the electronic interface housing 300 and to prevent the direct transmission of stresses appearing during snap-fit ​​fastening to the printed circuit board 5 and to the connection terminals 50 of the electrodes.

[0062] It is noteworthy that the recessed support elements—that is, the elements that are positioned away from the printed circuit board when the cover is placed on the base but not fixed—are arranged peripherally on the cover. This allows easy pressure to be applied to the cover in this peripheral area, enabling the eyelets 430 to deform towards the lugs 33.

[0063] The dimensions of the 500 gap, which allow for the longitudinal offset between the transverse planes 451 and 452, are calculated to allow, on the one hand, this deformation of the eyelets to ensure snap-fit ​​fastening, and on the other hand, to ensure contact between the pins 45 forming the support element and the printed circuit board when the cover 4 is snap-locked onto the base 3, as illustrated in the figure 5 . Since the fixing of the cover 4 on the base 3 is an elastic fixing by snap-fit, the eyelet 430 takes support on the corresponding lug 33 by generating a force in the opposite direction to the thrust force F1 on the cover previously mentioned, which implies a pressing of the pins 45 against the printed circuit board by a tilting effect of the deformed area 402 towards this board.

[0064] The invention thus makes it possible to produce an electronic interface housing 300 whose cover 4 has, on the one hand, thanks to the support members 44a, 44b and the support elements 405, a certain rigidity, and, on the other hand, thanks to the play 500, a flexibility allowing its attachment to the base 3 of the electronic interface housing 300 with a minimum stress on the fragile elements which are the terminals and connection assembly of the heating elements of an electric heating device 100 for a motor vehicle.

Claims

1. Cover (4) for an electronic interface housing (300) for an electric heating device (100) for a motor vehicle, the cover (4) comprising at least one support member (44a, 44b) and at least one support element (405, 45) configured to be in contact with a printed circuit board (5) when the cover (4) is fixed to the electronic interface box (300), a free end of the at least one support member (44a, 44b) extending in a first transverse plane (451) and a free end (4501) of the at least one support element (405, 45) extending in a second transverse plane (452), the at least one support member (44a, 44b) and the at least one support element (405, 45) being arranged to protrude in a direction perpendicular to a reference plane (400) of the cover (4) from an inner face (401) of the cover (4) intended to face the interior of the electronic interface box (300), characterised in that the first transverse plane (451) and the second transverse plane (452) are substantially parallel to each other and to the reference plane of the cover, strictly non-coincident with each other and with the reference plane (400) of the cover (4), the second transverse plane (452) being, in a direction perpendicular to it, closer to the reference plane (400) of the cover (4) than the first transverse plane (451).

2. Cover (4) according to the preceding claim, characterised in that an offset (500), measured perpendicular to the reference plane (400), between the first transverse plane (451) and the second transverse plane (452) is in the order of 1 to a few tenths of a millimetre.

3. Cover (4) according to any of the preceding claims, comprising means (430) for elastic snap-fit attachment to a base (3) of the electronic interface housing (300), characterised in that the at least one support element (405, 45) is located between a support member (44a, 44b) and an edge of the cover on which the elastic fastening means (430) are arranged.

4. Cover (4) according to any of the preceding claims, characterised in that the at least one support element comprises a plurality of pins (45) arranged to protrude from the inner face (401) of the cover (4), perpendicular to the reference plane (400) thereof.

5. Cover (4) according to the preceding claim, characterised in that the pins (45) of the at least one support element are arranged in a staggered pattern along at least two transverse lines (455, 456).

6. Cover (4) according to any one of claims 4 or 5, characterised in that the pins (45) constituting the at least one support element are arranged so as to protrude from a deformed area (402) of the inner face (401) of the cover (4).

7. Cover (4) according to any of the preceding claims, characterised in that the at least one support member (44a, 44b) comprises at least one rib (441a, 4410b, 4411b) substantially perpendicular to the first transverse plane (451).

8. Electronic interface housing (300) for an electric heating device (100) for a motor vehicle, comprising a cover (4) according to any of the preceding claims, as well as a base (3) configured to house a printed circuit board (5), the base (3) comprising latching means (33) configured to cooperate with elastic fastening means (43, 430) carried by the cover (4) in order to close a receiving cavity (35) for the printed circuit board (5).

9. Housing (300) according to the preceding claim, comprising an electrical connection area and a connection area for heating elements (2) of an electric heating device (100) for a motor vehicle, characterised in that the support element (45) of the cover (4) is located near the connection area to the heating elements (2) of the electric heating device (100).

10. Housing (300) according to one of claims 8 or 9, characterised in that the printed circuit board (5) is sandwiched between the at least one support member (44a, 44b) of the cover (4) and a reinforcing element (34) arranged in the base (3).

11. Electric heating device (100) for heating an air flow in a motor vehicle, comprising at least one heating element (2) and an electronic interface housing (300) according to any of claims 8 to 10.