FR3077459A1 - HEATING UNIT, HEATING RADIATOR AND AIR CONDITIONING UNIT, IN PARTICULAR A MOTOR VEHICLE - Google Patents

Abstract

The invention relates to a heating unit (12) comprising at least one heating element (20) for generating heat when it is traversed by an electric current, said heating element (20) having a first surface ( 22), said connecting faces, said heating element (20) further comprising one or more lateral flanges (34) extending from said first connection face, said heating unit (12) further comprising a first electrode (26) in electrical connection with the first connection face (22) for establishing said current in said heating element (20), said first connection face (22) having at least a first portion (35, 74) edge extending from an edge of the first electrode (26) to one or both of said side flanges (34).

Description

The present invention relates to a heating unit, a heating radiator comprising such a heating unit and an air conditioning unit equipped with such a heating radiator. It will find its applications, in particular, in the field of motor vehicles.

Electric heating radiators are known which are intended to be integrated into vehicle air conditioning units. These are either additional radiators, combined with heating radiators through which a heat transfer fluid flows, in vehicles with an internal combustion engine, or main radiators, in electric or hybrid vehicles.

Such radiators include a heating body accommodating heating units, provided with heating elements intended to generate heat when they are traversed by an electric current. Such heating units are intended to be brought into contact with an air flow passing through the radiator to heat said air flow.

Said heating units include electrodes in electrical connection with connection faces of the heating elements so as to allow the establishment of the current once the electrodes are respectively brought to different electrical potentials. The connection faces are connected by lateral flanges determining the spacing between the electrodes.

The question of the risk of a short circuit between the electrodes then arises, not only in the form of an initiation in the air or through any other medium separating the electrodes but also on the surface of the lateral edges. heating elements. The latter phenomenon can in particular occur when a film of dust and / or condensation is deposited on said edges, thus facilitating the establishment of a short-circuit current along the film from one electrode to another. . It has thus been demonstrated by the applicant that it is advisable to ensure a minimum distance along said flange between said connection faces.

A first solution in this sense would be to use thicker heating elements. However, this has many drawbacks, starting with an additional cost of said heating elements. In addition, the heating units in which the heating elements are installed would themselves have larger dimensions, thereby reducing the area left free for the flow of air flow through the equipped heating radiator.

The invention aims to at least partially overcome the drawbacks mentioned above and for this purpose provides a heating unit comprising at least one heating element, intended to generate heat when it is traversed by an electric current, said heating element having a first face, called connection faces, said heating element further comprising one or more lateral flanges extending from said first connection face, said heating unit further comprising a first electrode in connection electric with the first connection face for establishing said current in said heating element, said first connection face having at least a first edge portion extending from one edge of the first electrode to or at the one of said side edges.

In other words, on the first connection face, the edge portion is free, that is to say, is not covered by the first electrode. In other words, an edge of the first electrode is set back relative to an edge of the first connection face.

Thanks to said edge portion, the risks of short circuit along the side edges are limited. Indeed, any path connecting the first electrode and passing through one of said corresponding lateral flanges must also pass through said edge portion. This increases the distance to be covered in order to establish a possible short circuit.

According to other characteristics of the invention which can be taken together or separately:

the said heating element or elements have a second connection face,

the said lateral flange or flanges connect the said first and second connection faces,

said heating unit further comprises a second electrode in electrical connection with the second connection face for restoring said current,

- a distance between the first and the second electrodes is between 2 and 5 mm,

- a distance between the first and the second electrodes is

3.5 mm,

- the second of said connection faces has at least a second edge portion extending from one edge of the second electrode to or at one of said lateral edges,

- the first and second edge portions extend from the same lateral edge,

- the side edge (s) up to which the first and / or the second edge portion extend are straight,

- at least one of the other said lateral edges is oblique,

said oblique lateral rim (s) comprise an inclined panel connecting the first and the second connection face,

- The first and second electrodes each have at least one longitudinal edge respectively forming at least one of the edges of the first electrode and at least one of the edges of the second electrode from which one at least of the first portions of edge, said first longitudinal portion, and at least one of the second edge portions, said second longitudinal portion, extend so that said first and second longitudinal portions are in line with each other, said first and second electrodes respectively have first and second connection areas, intended to come respectively opposite the first and second connection faces, said first and second electrodes further having first and second connections respectively connecting said first and second connection areas, first and second bonds respectively defining first and second recesses in the first and second electrodes, the first link (s) passing to the right of the second recess (s) and the second link (s) passing to the right of the first recess (s),

- The first recesses define edges of the first electrode, called first recess edges, at least part of said first recess edges forming at least one of the edges of the first electrode from which at least one of the first edge portions extends, called the first transverse portion,

- The second recesses define edges of the second electrode, called second recess edges, at least part of said second recess edges forming at least one of the edges of the second electrode from which at least one of the second edge portions extends, called the second transverse portion,

- part of the first recesses is in line with part of the second recesses,

the first and second electrodes are in the form of a comb, the teeth of the comb respectively forming the first and second connection zones, spaces between the teeth respectively forming the first and second recesses and bridges of material between the teeth respectively forming the first and second bonds,

the first and second electrodes are in the form of a coil, enlarged parts of the coil respectively forming the first and second connection zones, thinner parts of the coil, connecting the enlarged parts in pairs, forming the first and second connections respectively, spaces between the enlarged zones respectively forming the first and second recesses,

- the first and second electrodes are identical and arranged by being turned 180 ° relative to each other,

- the first and second connection faces are substantially parallel,

the first and / or the second connection faces are substantially flat,

- the first and second electrodes are substantially parallel,

said first and / or second electrodes are substantially planar,

- said heating unit comprises a tube inside which said heating element or elements, said first electrode and / or said second electrode are located to electrically isolate them from the outside.

The invention also relates to a heating radiator comprising one or more heating units as described above.

The invention also relates to an air conditioning unit comprising a heating radiator as described above.

The invention will be better understood and other details, characteristics and advantages of the invention will appear on reading the following description given by way of non-limiting example and with reference to the appended drawings in which:

- Figure 1 schematically illustrates in front view an example of a heating radiator according to the invention,

FIG. 2 schematically illustrates, in cross section, a heating unit according to the invention,

FIG. 3 schematically illustrates a perspective view of a first and a second electrode and of heating elements of a heating unit according to a first embodiment of the invention,

- Figure 4 schematically illustrates a perspective view along a first orientation of a first and a second electrode, partially illustrated, and heating elements of a heating unit according to a second embodiment of the 'invention,

- Figure 5 schematically illustrates a perspective view in a second orientation, opposite to the orientation used in Figure 4 of the first and second electrodes, partially illustrated, and heating elements of the unit heater of figure 4,

FIG. 6 schematically illustrates a perspective view of first and second electrodes and heating elements of a heating unit according to a third embodiment of the invention,

FIG. 7 schematically illustrates a perspective view of an enlarged end part of the heating element of FIG. 6,

FIG. 8 schematically illustrates a perspective view of first and second electrodes and heating elements of a heating unit according to a fourth embodiment of the invention,

- Figure 9 schematically illustrates a perspective view of an enlarged end part of the heating element of Figure 8.

As illustrated in Figure 1, the invention relates to an electric heating radiator. It is, for example, a heating radiator, said to be high voltage, that is to say intended to be supplied by direct current (DC) or alternating current (AC) having an electrical voltage greater than 60 V , in particular between 60 and 1000 V, more particularly between 180 and 600 V, and / or allowing a heating power to be released on the air or a consumed electric power greater than 2 kW, in particular between 2 kW and 10 kW .

Said heating radiator comprises, for example, a heating body 10 supplied with electric current to heat a flow of air passing through said heating body 10.

Said heating body 10 here has a substantially parallelepiped configuration, extending on the surface. It is intended to be positioned transversely to the air flow to be heated. More specifically, said air flow is intended to be oriented perpendicular to said heating body 10, that is to say perpendicular to the plane of the figure.

The heating body 10 includes heating units 12, extending horizontally in the figure. Said heating body 10 may also include heat sinks 14, for example fins, in thermal contact relation with the heating units 12. The heatsinks 14 are positioned, in particular, between said heating units 12. Said heating body comprises in addition here a frame 16, in particular made of plastic, accommodating and holding said heating units 12 and / or the heat sinks 14. The air flow passes between the heating units 12, through the heatsinks 14.

Preferably, the heating radiator further comprises a unit 18 for distributing and / or controlling the current flowing in said heating body 10.

Said distribution and / or control unit 18 is advantageously configured to control the current supplying the heating body 10, in particular the various heating units 12, for example using piloted switches, making it possible to respectively control the circulation of current in each of the heating units 12. These are, in particular, transistors, for example of the Mosfet or IGBT type, operating in particular by pulse width modulation.

As illustrated in FIG. 2, the heating units 12 comprise at least one heating element 20, intended to generate heat when it is traversed by an electric current. The said heating element (s) 20 are, for example, PTC effect resistors (for positive temperature coefficient).

Said heating elements 20 have a first and here a second face 22, 24, called connection faces, intended to be brought to different electrical potentials for the establishment of said current in said heating elements 20.

Said heating unit 12 further comprises a first electrode 26, intended to be brought to first potential, and here a second electrode 28 intended to be brought to a second potential. These are, for example, metal electrodes. The first electrode 26 is in electrical connection with the first connection face 22 and the second electrode 28 is in electrical connection with the second connection face 24 thus allowing the circulation of current in the heating element or elements 20 when the first and second electrodes 26, 28 are supplied. For this, the first and second electrodes 26, 28 are preferably connected to said distribution and / or control unit 18. Said heating elements 20 are advantageously electrically connected in parallel between the electrodes 26, 28.

Said heating unit 12 may comprise a tube 30 inside which said heating element (s) 20, said first electrode 26 and / or said second electrode 28 are located to electrically isolate them from the outside of tube 30. Tubes 30 are preferably in contact with the dissipators 14.

Said heating units 12 also include layers of material 32, electrically insulating and thermally conductive, said layers of material 32 being located between each of the electrodes 26, 28 and one of the walls of the tube 30. In this way, the tube 30 is electrically isolated from the electrodes 26, 28 and the heating elements 20.

Said heating units 12 also advantageously comprise films of material, not illustrated, electrically conductive and respectively located between the first electrode 26 and the first connection face 22 and between the second electrode 28 and the second connection face 24 to maintain the or the heating elements 20 relative to the electrodes 26, 28 while allowing electrical connection between said electrodes 26, 28 and said heating element (s) 20. Said conductive films are respectively located on all of the facing surfaces of the first electrode 26 and of the first connection face 22 and / or of the second electrode 28 and second connection face 24, a portion 35, 37 of the surface of said first and / or of the second connection faces, in particular a edge part, possibly being left free, as will be detailed later.

The at least one heating element 20 further comprises one or more lateral flanges 34 connecting here said first and second connection faces 22, 24. They form the thickness of the heating elements 20 and determine the spacing between the electrodes 26, 28 , except to take into account the thickness of any conductive films.

The spacing between said first and second electrodes 26, 28 is, for example, between 2 and 5 mm. It is preferably from

3.5mm.

Advantageously, said connection faces 22, 24 are opposite and substantially parallel. They are substantially flat. The electrodes 26, 28 are substantially planar, mutually parallel and parallel to the connection faces 22, 24.

As illustrated in FIG. 3, said heating elements 20 are advantageously distributed regularly along the electrodes 26, 28. In other words, said heating elements 20 are advantageously distributed regularly along their respective heating units. The first and second electrodes 26, 28 have in this example a substantially identical shape. More specifically, said first and second electrodes 26, 28 are, for example, of elongated shape, in particular substantially rectangular.

Said first and second electrodes 26, 28 extend over the length of the tube of said heating unit.

The first and second connection faces 22, 24 are, for example, rectangular and the side edges 34 of the heating elements 20 are four in number, each of said edges 34 extending along one of the sides of the first and second connection face 22, 24. A large dimension of the heating elements 20 is here perpendicular to a large dimension of the first and second electrodes 26, 28.

According to the invention, as illustrated in Figures 3 and following, said first connection face 22 has at least a first edge portion 35, 74 extending from an edge of the first electrode 26 to or at one of said lateral flanges 34. In other words, on the first connection face 22, the edge portion 35 is free, that is to say is not covered by the first electrode 26. In other words, an edge of the first electrode 26 is set back with respect to an edge of the first connection face 22. In this way, the distance to be traveled on the surface of the heating elements is lengthened to follow a path passing through the corresponding lateral rim 34 and making it possible to join the first and second electrodes 26, 28. This limits the risk of short circuit.

Preferably, the second 28 of said connection faces also has at least a second edge portion 37, 78 extending from one edge of the second electrode 28 to or at one of said side edges 34. There is further increased in this way the distance to be covered for the establishment of a possible short circuit and / or one may be dealing with electrodes of non-rectangular configuration.

For some 35, 37 of them, the first and second edge portions extend from the same lateral edge 34.

Advantageously, the lateral edge (s) 34 to which the first and / or the second edge portion 35, 37 extend are straight, that is to say generated by a straight line, here they are planar, and perpendicular to the first and second connection faces 22, 24.

According to the embodiment of Figure 3, such first and second longitudinal portions 35, 37 are provided on each side of the heating elements 12 along opposite longitudinal edges of the first and second electrodes 26, 28. Thus, the side flanges 34 from which extend both a first and second edge portions 35, 37 are oriented parallel to the longitudinal axis of the heating elements 14.

At least one of the other said lateral edges 34 is oblique or beveled. By this is meant a non-straight rim, that is to say, a rim which is not both generated by a straight line and perpendicular to the two connection faces 26, 28. The distance between said first and second electrodes 26 , 28 along the surface of the oblique edges 34, is thus increased for the same spacing of said first and second electrodes 26, 28. It is advantageously at least 5 mm. The oblique lateral rim (s) 34 are here the lateral edges extending perpendicular to a longitudinal axis of the heating elements 12.

In the example, said oblique lateral edge or edges 34 comprise an inclined face 38 connecting the first and the second connection face 22, 24. By “inclined” is meant perpendicular neither to the first nor to the second connection face 26 , 28.

The inclined faces 38 and the first and second connection faces 26, 28 give in section to the heating element 20 a profile in the shape of a trapezoid. This is a cross section of the heating elements 20, that is to say a longitudinal section of the heating unit 12. In other words the first and second connection faces 22, 24 form the top and base of a truncated pyramid, two of the sides of which are straight and two of which are inclined. The angle formed between the second connection face 24 and the inclined faces is advantageously about 45 °.

The heating elements 20 all have the same orientation here. More precisely, the top of the truncated pyramid defined by the heating elements 20 is opposite the same electrode, here the first electrode 26.

Other orientations of the heating elements as well as other shapes with oblique edges are of course possible.

The first and second electrodes 26, 28 each have at least one longitudinal edge respectively forming at least one 36 of the edges of the first electrode and at least one 38 of the edges of the second electrode from which one 35 to less of the first edge portions, called the first longitudinal portion, and at least one of the second edge portions, said second longitudinal portion, extend so that said first and second longitudinal portions 35, 37 are at right one of the other. The first and second longitudinal portions are of the sort on either side of the corresponding lateral edge 34, that is to say of the lateral edge up to which said first and second edge portions 35, 37 extend. Said first and second longitudinal portions may have the same extension.

Said first and second portions 35, 37 have a distance, for example, of approximately 0.75 mm between said longitudinal edges 36, 38 of the first and second electrodes 26, 28 and the corresponding lateral flanges 34, that is to say say those oriented parallel to said longitudinal edges 36, 38.

In the embodiments of Figures 4 and following, said first and second electrodes 26, 28 respectively have first and second connection areas 60, 62, intended to come respectively opposite the first and second connection faces 22, 24. Said first and second electrodes 26, 28 also have first and second connections 64, 66 respectively connecting said first and second connection areas 60, 62. The first and second connections define first and second recesses 68, 70 respectively in the first and second electrodes 26, 28. The first connection (s) 64 pass to the right of the second recess (s) 70 and the second connection (s) 66 pass to the right of the first recess (s) 68.

The first recesses 68 define edges of the first electrode 26, called the first recess edges. At least part of said first recess edges forming at least one 72 of the edges of the first electrode 26 from which at least one of the first edge portions extends, called the first transverse portion. Said first transverse portion 74 has a distance, for example, of approximately 1.5 mm between said recess edge 72 of the first electrode 26 and the corresponding side edge 34, here a side edge 34 oriented perpendicular to the longitudinal axis heating elements 12.

The second recesses 70 define edges of the second electrode, called the second recess edges. At least part of said second recess edges forms at least one 76 of the edges of the second electrode 28 from which at least one of the second edge portions 78 extends, called the second transverse portion. Said second transverse portion 78 has a distance, for example, of about 1.5 mm between said recess edge 76 of the second electrode 28 and the corresponding side edge 34, here a side edge 34 oriented perpendicular to the longitudinal axis heating elements 12.

The first and second transverse portions 74, 78 are wider than the first and second longitudinal portions 35, 37 because the lateral rim parts corresponding to said transverse portions are directly in contact with the opposite electrodes 28, 26 rather than being adjacent another edge portion as with the longitudinal portions 35, 37.

Part of the first recesses 68 is in line with a part of the second recesses 70. In other words, the first connections 64 are not complementary to the second recesses 70 and the second connections 66 are not complementary to the first recesses 68.

In the embodiment of FIGS. 4 and 5, the first electrode 26 forms a ladder with a single longitudinal upright 80, provided with pairs of transverse bars 82. The bars 82 of the same pair are located on either side of the longitudinal upright 80. Each pair of bars 82 forms one of the first connection zones 60. The parts of the longitudinal upright 80 connecting the pairs of transverse bars 82 form the first connections 64 and the spaces between the neighboring bars 82 located at the same side of the longitudinal upright 80 forms the first recesses 68.

The second electrode 28 forms a ladder with two longitudinal uprights 84 connected by transverse bars 86, each transverse bar 86 forming one of the second connection zones 62. The parts of the longitudinal uprights 84 connecting the transverse bars 86 form the second connections 66 and the spaces between the neighboring bars 86 forming the second recesses 70.

In this way, the single longitudinal upright 80 of the first electrode 26 passes in line with the spaces between the bars 86 of the second electrode 28. The first and second transverse portions 74, 78 are respectively located on either side of the longitudinal upright single 80 and between the longitudinal uprights 84.

In the embodiment of Figures 6 and 7, the first and second electrodes 26, 28 are in the form of a comb. Teeth 88 of the comb respectively forming the first and second connection zones 60, 62. Spaces 90 between the teeth 88 respectively form the first and second recesses 68, 70 and bridges of material 92 between the teeth 88 respectively form the first and second connections 64, 66. The first and second electrodes 26, 28 are identical and arranged by being turned 180 ° relative to one another.

In this way the material bridges 92 of one of the combs pass in line with the spaces 90 between the teeth 88 of the other comb. The transverse edges 74, 78 extend perpendicular to the bridges of material 92.

In the embodiment of Figures 8 and 9, the first and second electrodes 26, 28 are in the form of a coil. Enlarged parts 94 of the coil respectively form the first and second connection zones 60, 62. Thinner parts 96 of the coil, connecting two by two the enlarged parts 94, respectively form the first and second connections 64, 66. Spaces 98 between the enlarged zones 92 respectively form the first and second recesses 68, 70. The first and second electrodes 26, 28 are identical and arranged by being turned 180 ° relative to each other.

In this way, the thinner parts 96 of one of the coils pass between the enlarged parts 94 of the other. The transverse edges 74, 78 extend perpendicular to said thinner parts 96.

The invention also relates to the heating units described above in themselves, such heating units being able to find their application in all types of heating device without necessarily being a heating radiator, in particular the described heating radiator.

The invention also relates to an air conditioning unit comprising a heating radiator as described above. Said housing comprises a body for circulating the air flow inside which said heating radiator is located.

Claims (10)

1. Heating unit (12) comprising at least one heating element (20), intended to generate heat when it is traversed by an electric current, said heating element (20) having a first face (22), said connection faces, said heating element (20) further comprising one or more lateral flanges (34) extending from said first connection face, said heating unit (12) further comprising a first electrode (26 ) in electrical connection with the first connection face (22) for establishing said current in said heating element (20), said first connection face (22) having at least a first portion (35, 74) of edge s 'extending from one edge of the first electrode (26) to or to one of said side flanges (34). 2. Heating unit according to the preceding claim, in which the said heating element (s) (20) have a second connection face (24), the said lateral flange (s) (34) connecting the said first and second connection faces (22, 24 ), said heating unit (12) further comprising a second electrode (28) in electrical connection with the second connection face (24) for establishing said current, the second of said connection faces having at least a second portion ( 37, 78) edge extending from an edge of the second electrode (28) to or at one of said side edges (34). 3. Heating unit according to the preceding claim wherein the first and second edge portions (35, 37) extend from the same side edge (34). 4. Heating unit according to any one of claims 2 or 3 in which the side rim (s) (34) up to which the first and / or the second edge portion (35, 37) extend are straight. 5. Heating unit according to any one of claims 2 and 3 wherein at least one of the other said side edges (34) is oblique. 6. Heating unit according to the preceding claim wherein said one or more oblique lateral edges include an inclined face (38) connecting the first and the second connection face (22, 24). 7. Heating unit according to any one of claims 2 to 5 in which the first and second electrodes (26, 28) each have at least one longitudinal edge (36, 38) respectively forming at least one of the edges of the first electrode (26) and at least one of the edges of the second electrode (28) from which one (35) at least of the first edge portions, called the first longitudinal portion, and one (37) at the less than the second edge portions, called the second longitudinal portion, extend so that the said first and second longitudinal portions (35, 37) are in line with one another. 8. Heating unit according to any one of claims 2 to 7 wherein said first and second electrodes (26, 28) respectively have first and second connection areas (60, 62), intended to come respectively opposite the first and second connection faces (22, 24), said first and second electrodes (26, 28) further having first and second connections (64, 66) respectively connecting said first and second connection areas (60, 62), first and second links (64, 66) respectively defining first and second recesses (68, 70) in the first and second electrodes (26, 28), the first link (s) (64) passing in line with the second recess (s) ( 70) and the second link (s) (66) passing to the right of the first recess (s) (68). 9. Heating radiator comprising one or more heating units (12) according to any one of the preceding claims. 10. Air conditioning unit comprising a heating radiator according to the preceding claim.