FR3081542A1 - HEATING DEVICE FOR MOTOR VEHICLE - Google Patents

Abstract

The invention relates to an electric heating device (10) in particular for a motor vehicle, comprising: - one or more heating modules (12), in particular each provided with a heating body (22), preferably of the type positive temperature coefficient, arranged to generate heat when an electric current flows through them, each module (12) comprising a thermal envelope (26) arranged to conduct the heat generated by the heating body (22), - a plate (101) comprising at least one opening through which extends one of the heating modules, - a sealing member (104) in contact with the plate and surrounding at least one of the heating modules (12) so as to seal said opening of the plate, in particular leaktight against water or dust, the sealing member being arranged in contact with the heating module on the thermal envelope of this heating module , especially only nt on the thermal envelope of this heating module.

Description

The present invention relates to a heating module for a heating device for a motor vehicle, in particular for a high-voltage heating device for an electric or hybrid motor vehicle.

It is known to provide a motor vehicle with a heating device. Such a heating device can in particular be used to heat air before it enters the passenger compartment of the motor vehicle.

In the context of an electric motor vehicle, in particular, it is known to use a so-called "high voltage" heating device. Such a heating device is conventionally supplied with a voltage between 100 V and 1000 V.

This heating device can in particular be integrated into a heating, ventilation and / or air conditioning installation (called "HVAC unit" from the English "heating, ventilation and air-conditioning"). In this case, the heating device is for example arranged downstream of the cooling liquid heating core.

Such a heating device conventionally comprises heating units, each received in a tube, the tubes being in contact with fins aimed at improving the heat exchange with the air to be heated. Each heating unit comprises for example one or more heating bodies, electrically powered by two electrodes, the whole of the heating body (s) and the two electrodes being covered by a layer of electrical insulator. The heating element is for example a stone made of a resistance material with a positive temperature coefficient (or PTC, from the English "positive temperature coefficient").

An object of the invention is to improve the sealing of these devices.

To this end, the invention relates to an electric heating device in particular for a motor vehicle, comprising:

- one or more heating modules, in particular each provided with a heating body, preferably of the type with a positive temperature coefficient, arranged to generate heat when they are traversed by an electric current, each module comprising a thermal envelope arranged to conduct the heat generated by the heater,

- a plate comprising at least one opening through which extends one of the heating modules,

a sealing member in contact with the plate and surrounding at least one of the heating modules so as to seal said opening of the plate, in particular leaktight with respect to water or dust, the member sealing being arranged in contact with the heating module on the thermal envelope of this heating module, in particular only on the thermal envelope of this heating module.

Thanks to the invention, an improved seal is obtained in a relatively simple manner. The invention allows the sealing member to extend over a relatively small height, while ensuring good sealing.

The invention also allows the electrodes to be left free, which makes assembly operations easier.

According to one aspect of the invention, the sealing member extends a portion of the height of the thermal envelope of the heating module.

According to one aspect of the invention, the sealing member is arranged to leave the electrodes of the heating module free, namely is not in contact with these electrodes.

According to one aspect of the invention, the sealing member is arranged to leave free a layer of electrical insulator between the envelope and the electrodes, namely is not in contact with this layer.

According to one aspect of the invention, the sealing member is arranged to surround all the heating modules.

According to one aspect of the invention, the plate has an outer peripheral rim so as to form a swimming pool for receiving the sealing member.

According to one aspect of the invention, the plate has an elongated shape, and has a plurality of openings for a plurality of heating modules.

According to one aspect of the invention, this plate is made for example from steel, aluminum or plastic.

According to one aspect of the invention, the sealing member comprises a silicone.

According to one aspect of the invention, the sealing member is in contact with at least one pad of an electronic device.

According to one aspect of the invention, this stud is at least partially pressed into the sealing member.

According to one aspect of the invention, the stud comprises a transverse collar arranged to rest on an external surface of the sealing member.

According to one aspect of the invention, the stud thus comprises a pin and this flange, these elements being made for example of plastic or aluminum.

According to one aspect of the invention, this or these studs being integral with a support for electronic components, or Driver in English.

According to one aspect of the invention, the electronic device forms a cover closing one end of the electric heating device.

According to one aspect of the invention, the electronic device has passages for letting the electrodes of the heating modules (12) pass to the electronic components.

The invention also relates to an electric heating device in particular for a motor vehicle, comprising:

- one or more heating modules, in particular each provided with a heating body, preferably of the type with a positive temperature coefficient, arranged to generate heat when they are traversed by an electric current, each module comprising a thermal envelope arranged to conduct the heat generated by the heater,

- an electronic device arranged to close one end of the electric heating device.

The invention also relates to a method for manufacturing an electric heating device (10) in particular for a motor vehicle, comprising:

- one or more heating modules, in particular each provided with a heating body, preferably of the type with a positive temperature coefficient, arranged to generate heat when they are traversed by an electric current, each module comprising a thermal envelope arranged to conduct the heat generated by the heater,

- a plate comprising at least one opening through which one of the heating modules extends, the method comprising the step:

- Form a sealing member in contact with the plate and surrounding at least one of the heating modules so as to seal said opening of the plate, in particular sealed against water or dust, the sealing member being arranged in contact with the heating module on the thermal envelope of this heating module, in particular only on the thermal envelope of this heating module.

The method may include the step of depositing a material intended to form the sealing member so as to surround the heating module or modules.

The method may include the step of booing this material, in particular in contact with a pad of an electronic device.

The module can also include one or more of the following characteristics, taken separately or in combination:

at least one of the first and second parts is configured to be deformed, in particular configured to be deformed plastically or elastically, so as to enclose the other part with which it is assembled, the thermal envelope surrounds the heating unit over substantially its entire periphery , the first and second parts are assembled together in a detachable manner, the first and second parts are assembled together so as to keep tight between said first and second parts, the heating body, the electrodes and the layer of electrical insulator, the first and second parts each comprise at least one fastening element, the fastening element of the first part is arranged to cooperate with the fastening element of the second part to assemble the first and second parts together, the body of heater includes one or more resistive elements, including a or several ceramics, the module comprises fins configured to increase the heat exchanges between the thermal envelope and the air to be heated, the fins are brazed or glued to the thermal envelope, so as to ensure thermal transfer by conduction between the 'envelope and the fins, each of the first and second parts comprises at least one main face which is parallel to the main face of the other part with which it is assembled, the main faces of the first and second parts are arranged on the side and d other of the heating unit, the main faces are facing the heating body, the electrodes are held tight against the heating body between the main faces, the main faces of the first and second parts are delimited by a main plate respectively of the first and of the second part, each main plate ensuring the thermal transfer p ar conduction between the heating unit and the fins, the main faces of the first and second pieces have the same surface area, the main faces of the first and second pieces are flat, the fins are brazed on the main plates, a main plate is rectangular , at least one of the first and second parts comprises a rim, the rim extends over at least part of the periphery of the main face, the rim extends perpendicular to the main face.

According to yet another aspect, the invention relates to a method for manufacturing an electric heating module for a heating device for a motor vehicle comprising the step consisting in:

deform, in particular deform plastically or elastically one of the first and second parts so as to enclose the other part and assemble the first and second parts therebetween.

According to a nonlimiting embodiment, the method comprises a step consisting in:

assemble the first and second pieces so as to keep tight between them, the heating body, the electrodes and the layer of electrical insulation.

The invention also relates to a heating device for a motor vehicle comprising a plurality of heating modules as described above in all of their combinations.

The invention will be better understood on reading the description which follows, given solely by way of example and made with reference to the drawings in which:

- Figure 1 shows a side view of an example of a heating device according to the invention;

- Figure 2 shows an assembled view of a heating module according to a first embodiment;

- Figure 3 shows an exploded view of the heating module according to the first embodiment;

- Figure 4 shows an enlarged view of the cover according to the first embodiment;

- Figure 5 shows an assembled view of a heating module according to a second embodiment;

- Figure 6 shows an exploded view of the heating module according to the second embodiment;

- Figure 7 shows a sectional view of the heating module according to the second embodiment in a first assembly position;

- Figure 8 shows a sectional view of the heating module according to the second embodiment in a second assembly position,

- Figures 9 to 11 illustrate another embodiment of the invention.

FIG. 1 shows, in side view, an example of a high-voltage heating device 10 for a motor vehicle. Such a heating device 10 is used in particular in electric and hybrid motor vehicles. Such a heating device 10 is for example supplied with a current whose voltage is between 100 V and 1000 V. Such a heating device 10 comprises a plurality of heating modules 12.

The electrical supply of the heating modules 12 can be carried out by means of an electronic control unit (not shown).

The heating module 12 essentially comprises a heating unit 20. More specifically, the heating unit 20 comprises, in accordance with the invention, a heating body 22, sandwiched between two electrodes 24, a layer of electrical insulator (not shown) surrounding the assembly formed by the heating body 22 and the two electrodes 24 and a thermal envelope 26 arranged to conduct the heat generated by the heating body 22. In the example illustrated, the thermal envelope 26 surrounds the heating unit 20 over substantially its entire periphery. The heating body 22 generates heat by Joule effect when a current flows through it.

The thermal envelope 26 is for example in one of the metals among aluminum, copper, brass. The thermal envelope 26 can be made of a single metal or can be made of different metals or alloys. The thermal envelope 26 serves as a thermal interface between in particular the heating unit 20 and the other elements of the heating device 10 as well as the air to be heated.

The function of the electrical insulating layer is to avoid a short circuit through the thermal envelope 26 between the various elements of the heating unit 20. The electrical insulating layer is preferably made of a material which is a good conductor of heat, in order to allow a significant heat exchange between the heating body 22 and the air to be heated surrounding the thermal envelope 26. For example, the layer of electrical insulator is made of one of the materials among the alumina or a polyimide-type synthetic material, Kapton®. For reasons of clarity of the figures, this layer of electrical insulation is not shown.

The heating body 22 is for example a stone made of a resistance material with a positive temperature coefficient, such as a ceramic. Thus, the resistance of the heating body 22 increases with the temperature of this heating body 22.

The heating unit 20 can comprise several heating bodies 22.

The electrodes 24 can in particular be made of one of the metals among aluminum, copper, brass.

In the example illustrated, the module comprises fins configured to increase the heat exchanges between the thermal envelope and the air to be heated. One can in particular choose as shape for the fins 14 any geometry allowing for example to increase the heat exchanges with the air to be heated. The fins 14 are, in the example illustrated, brazed to the thermal envelope 26. According to an alternative embodiment, the fins can be bonded to the envelope 26.

The thermal envelope 26 is now described in more detail.

The thermal envelope 26 comprises a first part 28a and a second part 28b. The first and second parts 28a; 28b are detachably assembled together. It will be understood by this that the first part 28a can be separated from the second part 28b without causing even partial destruction of the first and / or the second part 28a; 28b. In particular, the first part 28a and / or the second part 28b are configured to be plastically and / or elastically deformed, so as to enclose the other part 28a; 28b with which it is assembled so as to assemble the first and second parts 28a; 28b between them.

The first and second parts 28a; 28b keep tight between them, the heating body 22, the electrodes 24 and the layer of electrical insulator. Intimate contact between the different elements of the heating module 12 is advantageous in order to promote the conduction of the heat generated by the heating body 22 towards the outside of the heating module 12. The heat generated by the heating body 22 is thus conducted efficiently through the electrodes 24 and the layer of electrical insulator to the thermal envelope 26, which dissipates the heat in the air to be heated. In particular, the heat is transmitted by conduction from the thermal envelope 26 to the fins 14, then and evacuated by convection, natural or forced, between the surface of the fins 14 and the air to be heated.

In order to achieve a detachable assembly of the first and second parts 28a; 28b, these include fixing elements arranged to cooperate with each other. Thus, a fastening element of the first part 28a cooperates with at least one fastening element of the second part 28b.

Each of the first and second parts 28a; 28b has at least one main face 30a; 30b which is parallel to the main face 30a; 30b in the other room 28a; 28b with which it is assembled. The main faces 30a; 30b of the first and second parts 28a; 28b are arranged on either side of the heating unit 20. In the example illustrated, the main faces 30a; 30b are opposite the heating body 22 and the electrodes 24 are held tight against the heating body 22 between these main faces 30a; 30b.

The main face 30a of the first part 28a is delimited by a main plate 32a of the first part 28a. Similarly, the main face 30b of the second part 28b is delimited by a main plate 32b of the second part 28b. It will be understood here that each of the main plates 32a; 32b constitutes a face of a plate, called the main plate, the thickness of which is negligible compared to the other dimensions, the plate thus constituting a wall of the first and second part 28a respectively; 28b. The fins 14 are brazed or glued to each of the main plates 32a; 32b, the main plates 32a; 32b thus ensuring thermal transfer by conduction between the heating unit 20 and the fins 14.

In the example illustrated, the main faces 30a; 30b of the first and second parts 28a; 28b therefore comprise a flat face, of a rectangular plate or wall of the first part 28a and the second part 28b respectively.

H is possible to provide a member for sealing between the first and second parts 28a; 28b, for example a seal 34.

According to a first embodiment illustrated in FIGS. 2 to 4, the first part 28a is configured to be plastically deformed so as to grip the second part 28b. The first and second parts 28a; 28b are, in this embodiment, crimped to each other.

The crimping of the first and second pieces 28a; 28b between them makes it possible not to have recourse to welding to assemble the first and second parts 28a; 28b between them. The heating module 12 is thus in no way affected thermally during an assembly operation, which further reduces the risk of damage to a component of this module 12.

As visible in FIG. 3, the first part 28a forms a receptacle for the heating unit 20, the receptacle has an opening 36 for the insertion of the heating unit 20. The second part 28b forms a cover which s' adapts to said opening 36.

The first part 28a in particular has a rim 38 which extends over a part of the periphery of the main face of said first part 28a, perpendicular to said first part 28a. The rim 38 extends in the example illustrated on at least three sides of the periphery of the main face 30a of the first part 28a. The rim 38 thus delimits the opening 36 of the receptacle for the insertion of the heating unit 20. The main plate 32a of the first part 28a forms a bottom for the receptacle.

In this embodiment, the fastening elements of the first part 28a are in the form of tenons 40, each tenon 40 taking, in this embodiment, the form of a tongue. A lug 40 of the first part 28a is configured to be plastically deformed so that the first part 28a encloses the second part. The pins 40 are advantageously made in the form of slots in the rim 38. This further simplifies the manufacture of the first part 28a, and in particular the manufacture of the fastening elements.

The fastening elements of the second part 28b are in the form of holes 42 (not shown in FIG. 3) cut from the main plate 32b of the second part. The pins 40 cooperate with the orifices 42 in order to assemble the first and second parts 28a; 28b between them. In such an assembly, the pins 40 are arranged to keep clamped between the first and the second part 28a; 28b the heating body 22, the electrodes 24 and the layer of electrical insulator.

According to the first embodiment, pins 40 are arranged on the periphery of the first part 28a and are spaced regularly from each other. The orifices 42 of the second part 28b are arranged on the periphery of the main plate 32b of the second part 28b and are spaced regularly from one another so as to each cooperate with one of the tenons 40.

According to a second embodiment illustrated in Figures 5 to 8, the first and second parts 28a; 28b are configured to be assembled together by elastic deformation of at least one of the first and second parts 28a; 28b so that one of the first and second parts 28a; 28b encloses the other room 28a; 28b with which it is assembled.

In this embodiment, each of the first and second parts 28a; 28b includes first and second flanges 38a; 38b; 39a; 39b. The first edge 38a; 39a extends on a first side of the periphery of the main face 30a; 30b of each of the first and second parts 28a, respectively; 28b and the second rim 38b; 39b extends over a second side of the periphery of said main face 30a; 30b, the second side being opposite the first side.

A fastening element of the second part 28a is in the form of a rib 44 on a flange 39a; 39b of the second part 28b, said rib 44 thus forming a protusion on the rim 39a; 39b of the second room 28b. The rib 44 is configured to anchor the second part 28b in at least one recess formed in a flange 38a; 38b of the first part 28a. The recesses are, in the example illustrated, constituted by two parallel grooves 46E; 46C formed in each of the flanges 38a; 38b of the first part 28a.

As illustrated in the sectional views of Figures 7 and 8, the flanges 38a; 38b of the first part 28a therefore each comprise two grooves 46E; 46C and ledges 39a; 39b of the second part 28b each comprise a rib 44. In particular, each of the flanges 38a; 38b of the first part 28a has a first groove, called the extreme groove 46E, extending along the rim 38a; 38b, near the distal free end of said flange 38a; 38b. Each of the flanges 38a; 38b of the first part 28a further comprises a second groove, called central groove 46C, extending along said rim 38a; 38b, between the extreme groove 46E and the periphery of the main face 30a. The central groove 46C extends between the extreme groove 46E and the edge which intersects between the flange 38a; 38b and the main plate 32a of the first part.

Each of the ribs 44 is in the example illustrated rectilinear and cooperates by complementary shape with at least one groove 46E; 46C, itself straight.

FIGS. 9 to 11 show an electric heating device 100 comprising:

- Several heating modules 12, as described above, each provided with a heating body 22, of the type with a positive temperature coefficient, arranged to generate heat when they are traversed by an electric current, each module 12 comprising a thermal envelope 26 arranged to conduct the heat generated by the heating body 22,

- a plate 101 comprising openings 102 through each of which extends one of the heating modules 12, as best seen in FIG. 11,

a sealing member 104 in contact with the plate 101 and surrounding the heating modules 12 so as to seal the openings 102 in the plate 101, in particular leaktight with respect to water or dust, the member seal 104 being arranged in contact with the heating module on the thermal envelope 26 of this heating module, here only on the thermal envelope of this heating module.

The openings 102 are aligned along a longitudinal axis.

The sealing member 104 extends a portion of the height of the thermal envelope 26 of each heating module 12.

The sealing member 104 is arranged to leave the electrodes 24 of the heating module free, that is to say that it is not in contact with these electrodes 24.

The plate 101 has an outer peripheral rim 105 so as to form a swimming pool for receiving the sealing member 104.

The plate 101 has an elongated shape, and has a plurality of openings 104 for a plurality of heating modules 12.

The sealing member 104 comprises a silicone, and is in one piece.

The sealing member 104 is in contact with studs 108 of an electronic device 110.

Each stud 108 is at least partially pressed into the sealing member 104.

The stud 108 includes a transverse flange 111 arranged to rest on an outer surface 112 of the sealing member 104.

The stud 113 sinks into the silicone.

These pads 108 are integral with a support 120 of electronic components, or Driver in English.

The electronic device 110 includes a cover 121 closing one end 122 of the electric heating device 10.

The electronic device 110 has passages 128 for letting electrodes 24 of the heating modules 12 pass to the electronic components 130.

The method of manufacturing the device 10 may include the step of depositing a material intended to form the sealing member 104 so as to surround the heating module or modules 12.

The method may include the step of booing this material, in particular in contact with a pad 111 of an electronic device.

The device 10 comprises a frame 140 housing the heating modules 12.

The frame 140 has one end receiving the plate 101, and has lateral uprights 141.

The electronic device 110 cooperates with this frame 140, for example by snap-fastening, preferably by means of snap-fastening forms 180 formed on the uprights 141, which are here openings, and snap-in forms 181 formed on the device electronics, which here are snap tabs.

This simplifies mounting, while not affecting the seal.

It is not beyond the scope of the present invention when one or certain envelopes are devoid of a heating body. This makes it possible to adapt to thermal needs. For example, if there are 8 envelopes in the device, 6 could contain a heating element and 2 do not.

Claims (9)

1. Electric heating device (10) in particular for a motor vehicle, comprising: - one or more heating modules (12), in particular each provided with a heating body (22), preferably of the type with a positive temperature coefficient, arranged to generate heat when they are traversed by an electric current, each module (12) comprising a thermal envelope (26) arranged to conduct the heat generated by the heating body (22), - a plate (101) comprising at least one opening through which extends one of the heating modules, - A sealing member (104) in contact with the plate and surrounding at least one of the heating modules (12) so as to seal said opening of the plate, in particular watertight with respect to water or dust, the sealing member being arranged in contact with the heating module on the thermal envelope of this heating module, in particular only on the thermal envelope of this heating module. 2. Device according to the preceding claim, wherein the sealing member (104) extends over a portion of the height of the thermal envelope of the heating module. 3. Device according to claim 1 or 2, wherein the sealing member (104) is arranged to leave free of the electrodes of the heating module, namely is not in contact with these electrodes. 4. Device according to one of the preceding claims, in which the sealing member is arranged to surround all the heating modules (12). 5. Device according to one of the preceding claims, in which the plate (101) has an external peripheral rim so as to form a swimming pool for receiving the sealing member. 6. Device according to one of the preceding claims, in which the sealing member comprises a silicone. 7. Device according to one of the preceding claims, in which the sealing member is in contact with at least one stud (111) of an electronic device. 8. Device according to the preceding claim, wherein this stud (111) is at least partially pressed into the sealing member. 9. Method for manufacturing an electric heating device (10) in particular for a motor vehicle, comprising: - one or more heating modules (12), in particular each provided with a heating body (22), preferably of the type with a positive temperature coefficient, arranged to generate heat when they are traversed by an electric current, each module (12) comprising a thermal envelope (26) arranged to conduct the heat generated by the heating body (22), - a plate comprising at least one opening through which one of the heating modules extends, the method comprising the step: - Form a sealing member in contact with the plate and surrounding at least one of the heating modules (12) so as to seal said opening of the plate, in particular sealed with respect to water or dust , the sealing member being arranged in contact with the heating module on the thermal envelope of this heating module, in particular only on the thermal envelope of this heating module.