Heating device

Abstract

Heating device (12) for a motor vehicle, comprising an electric heating unit (86, 96, 102, 118, 136, 146) having heating elements (90, 99, 104, 122, 138, 150), and a corrugated rib arrangement (92, 98, 106, 120, 146, 148) having corrugated ribs (76, 78, 95, 97, 109, 111, 132, 134, 144, 148, 154), characterized in that the corrugated ribs (76, 78, 95, 97, 109, 111, 132, 134, 144, 148, 154) form a deformed radius (88, 108), wherein a large contact area (79, 114, 128, 142) is formed between the heating elements (90, 99, 104, 122, 138, 150) and the corrugated fins (76, 78, 95, 97, 109, 111, 132, 134, 144, 148, 154), wherein the large contact area (79, 114, 128, 142) of the corrugated fins (76, 78, 95, 97, 109, 111, 132, 134, 144, 148, 154) has a planar section (80) and wherein the deformed radius (88, 108) is a contact radius (88, 108) with r T>0.5 mm, wherein the corrugated rib (76, 78, 95, 97, 109, 111, 132, 134, 144, 148, 154) is designed as a trapezoidal rib (76, 95, 109, 132, 144) or as an omega rib (78, 97, 111, 134, 148), and wherein the corrugated ribs (76, 78, 95, 97, 109, 111, 132, 134, 144, 148, 154) are fixed by means of gluing, wherein in the case of the trapezoidal rib the adhesive surface is formed between the contact surfaces and in the case of the omega rib the contact surfaces are located next to each other and the adhesive is arranged outside the contact surfaces as an adhesive surface at the edge of the omega rib.

Description

Technical field

[0001] The invention relates to a heating device, in particular for a motor vehicle, according to the preamble of claim 1. State of the art

[0002] In motor vehicles, heating devices are typically required as electric auxiliary heaters in fuel-efficient combustion engines, plug-in hybrids / range extenders, and electric drives, for example, for cabin heating. These electric auxiliary heaters are primarily needed during the start-up phase and at low ambient temperatures and are well-suited because the electrical power can be converted into noticeable heat immediately. Electric auxiliary heaters for fuel-efficient combustion engines are generally air-side electric heaters powered by the low-voltage 13 V electrical system. The electric auxiliary heater typically has at least one heating element and corrugated fins. Common heating elements include PTC (Positive Temperature Coefficient) heating elements and resistance heating elements with resistive tracks.

[0003] In hybrid and / or purely electric vehicles (EVs), the importance of electric auxiliary heaters is greater, as these vehicles lack a conventional coolant heater. Electric auxiliary heaters with a power output greater than 3 W are typically required. These hybrid and / or EVs typically have an electrical system voltage higher than 60 V, sometimes even higher than 300 V. Due to the high heating requirements, the electric auxiliary heater is usually operated at the higher voltage of the vehicle's electrical system to minimize the current draw. Therefore, reliable contact protection is essential to prevent hazards during operation and / or maintenance. Consequently, all electrically conductive components of the electric heater that are accessible from the outside must be potential-free.

[0004] DE 10 2007 027 922 A1 describes a method for manufacturing a PTC heating device. The heating device comprises a plurality of PTC rods, each PTC rod having a built-in PTC element that generates heat when supplied with an electric current. Furthermore, the heating device comprises a plurality of heat-radiating fins attached to both sides of the PTC rods along a longitudinal direction, as well as an upper and a lower housing in which the PTC rods are arranged, the heat-radiating fins being connected to the PTC rods by means of a thermally conductive adhesive.

[0005] WO 2005 / 049350 A1 describes a PTC element module and an auxiliary heater with a PTC element module for a motor vehicle. The auxiliary heater comprises a PTC element module with a PTC element, a heat sink array arranged parallel to both sides of the PTC element module, positive and negative terminals arranged parallel to the heat sink array, and a housing containing the PTC element modules and the heat sink array. Furthermore, insulating elements are provided, having a "⊃"-shaped or rectangular form.

[0006] DE 20 2004 016 942 U1 discloses a heating module with a bonded corrugated fin.

[0007] DE 203 01 114 U1 discloses a resistance heating device with a corrugated fin and rubber insulation.

[0008] DE 201 18 511 U1 discloses a heat exchanger network with flat tubes and fins that are arranged in layers and clamped together.

[0009] DE 10 2006 035 209 A1 discloses a corrugated rib with wave crests and wave troughs, wherein the bending edges are weakened so that the springback occurring during bending is reduced.

[0010] DE 21 14 340 A discloses a finned tube heat exchanger with fin packs between flat tubes.

[0011] JP 2001-255 091 A discloses a heat exchanger with a fin and an arc-shaped end face.

[0012] DE 10 2010 004 034 A1 discloses an electric heating device with a metallic heating fin structure with busbars and an electrically conductive coupling layer.

[0013] DE 10 2011 000 116 A1 discloses an electric heating device with an insulation structure.

[0014] EP 1 061 776 A1 discloses a positioning frame for an electric heating device.

[0015] DE 198 35 229 A1 discloses a fluid-flow heat exchanger with electric heating units between the fluid-flow tubes, wherein the electric heating units have corrugated fins which are arranged in a press fit. Description of the invention, problem, solution, advantages

[0016] The purpose of the invention is to create an improved heating device.

[0017] This is solved with a heating device having the features of claim 1.

[0018] One embodiment of the invention relates to a heating device, in particular for a motor vehicle, with an electric heating unit comprising heating elements and a corrugated fin arrangement comprising corrugated fins, wherein the corrugated fins form a deformed or deformable radius, and wherein a large contact area is formed between the heating elements and the corrugated fins.

[0019] According to the invention, the large contact surface of the corrugated ribs has a planar section.

[0020] According to the invention, in the heating device the deformed or deformable radius is a contact radius with r T >0.5 mm. A large contact radius with r T A value greater than 0.5 allows for the creation of a large, flat planting area.

[0021] According to the invention, the corrugated rib is designed as a trapezoidal rib or an omega rib. The trapezoidal rib and / or the omega rib can preferably be formed by contact pressure during the assembly of the corrugated rib with the heating element. Alternatively, the corrugated rib can also be designed as a trapezoidal rib and / or an omega rib before assembly.

[0022] The heating element of the heating device can be designed as a PTC heating element. Alternatively, the heating element can be designed as a resistance heating element, preferably as a thick-film resistance heating element. In this case, the resistance heating element preferably has resistive tracks arranged on a ceramic substrate, in particular on an Al₂O₃ ceramic substrate.

[0023] The heating device can have a low-voltage heating unit or a high-voltage heating unit. A low-voltage heating unit operates at voltages below 60 V, while a high-voltage heating unit can operate at voltages above 60 V.

[0024] Preferably, the heating device comprises a contact element and / or an insulating element. In a preferred embodiment, the large contact area of ​​the corrugated fins can function as the contact surface. This allows the large contact area to be arranged directly on the, for example, PTC heating element.

[0025] Preferably, in a non-inventive example, the corrugated rib can be fixed by clamping it to the heating element. In addition to fixing the rib, this clamping action can generate high contact pressure, which increases the deformable radius of the corrugated rib and creates the deformed radius with the large contact area.

[0026] The corrugated rib arrangement preferably exhibits high stiffness. This prevents breakage or bending of the insulating layer, preferably an insulating ceramic, under mechanical stress exerted on the heating element. In particular, an omega rib exhibits high stiffness.

[0027] Preferably, the corrugated fin can be fixed to the heating element by means of adhesive bonding. Alternatively, in a non-inventive example, tensioning with a spring can be used. Fixing the corrugated fins and / or the heating elements can be achieved by means of adhesive bonding and / or tensioning.

[0028] The invention is based on the idea that an improved heating device can be created by appropriately selecting the corrugated fins. The corrugated fins, which are preferably formed from a sheet, particularly an aluminum sheet, have a better contact area with the heating element due to their large contact surface. This large contact area can be achieved by means of a deformable radius of r. TA radius greater than 0.5 mm can be achieved, which can be deformed during the assembly process. This results in a deformed radius in the heating device at the interface between the corrugated fin and the heating element. The deformation preferably creates a flat surface on the corrugated fin, essentially parallel to the surface of the heating element. The large contact area represents a surface with dimensions of a few millimeters in width multiplied by the dimensions of one fin length, which is derived from one fin depth.

[0029] The large contact area improves heat transfer between the heating element and the corrugated fin. This is an advantage over the V-shaped corrugated fins used in the prior art, which have a point-like contact area and are less efficient due to their significantly smaller radius r. T< 0.5 mm is the case. The corrugated rib with the deformed radius also exhibits high inherent stability and strength. The deformed radius of the corrugated rib compensates for unevenness in the mating contact surface, particularly on the surface of the heating element facing the corrugated rib. If the corrugated ribs have a radius > 0.5 mm due to manufacturing processes, the contact surface can be formed with a flat surface element during assembly by means of contact pressure. Thus, a trapezoidal rib can only be formed after the heating unit is mounted. The contact pressure can preferably be achieved by spring pressure or by bonding the corrugated ribs to the heating element. However, corrugated ribs that are already formed as trapezoidal ribs due to manufacturing processes and already have a flat contact surface before the heating unit is mounted can also be used.

[0030] In the low-voltage heating device embodiment, the heating unit preferably includes a contact plate. In the high-voltage heating unit embodiment, a sheathing tube can be provided, which encloses the heating element and an electrical insulating element. The surface facing the corrugated fins can be made of an electrically insulating material, in particular, for example, an insulating ceramic. Especially in this embodiment, the large contact area of ​​the corrugated fins is advantageous because the lower thermal conductivity of the insulating ceramic compared to aluminum can be compensated for by the large contact area, and good heat transfer between the corrugated fins and the heating element can be achieved. The omega-shaped fin design can further increase the contact area. The advantage here is that even in the low-voltage heating unit, a contact electrode can be omitted.The corrugated fins can be used in both a gill-like design and one with deep corrugations. The deep corrugations can further increase heat transfer.

[0031] Further advantageous embodiments are described by the following figure description and by the dependent claims. Brief description of the figures in the drawing

[0032] The invention is explained in more detail below based on at least one embodiment with reference to the figures in the drawing. These show, in schematic representation: Fig. 1. An air conditioner with an electric heater, Fig. 2 an electric heater in accordance with the state of the art, Fig. 3 an electric heater with a heating element in accordance with the state of the art, Fig. 4 another embodiment of an electric heater according to the prior art, Fig. 5 another embodiment of the heater according to the prior art, Fig. 6 another embodiment of the heater according to the prior art, Fig. 7 another embodiment of the heater according to the prior art, Fig. Comparison of 8 different rib shapes of a corrugated rib of a heater according to the prior art and of a heater according to the invention, Fig. 9 a rib on a contact plate according to the invention, Fig. 10 a rib arranged on a heating element according to the invention, Fig. 11 a rib arranged on a sheath tube according to the invention, Fig. 12 a rib which is arranged directly on an insulator, according to the invention, Fig. 13 a rib arranged on a heating ceramic according to the invention, Fig. 14 a heating element with a rib arranged on a heating ceramic, according to the invention, Fig. 15 a section of the heating element of Fig. 15, Fig. 16 embodiments of heating elements according to the invention. Preferred embodiment of the invention

[0033] Fig. Figure 1 shows a schematic representation of an air conditioning system 10 with an electric heating device 12, particularly for a motor vehicle 14. The engine compartment 16, in which the components of the air conditioning system 12 are arranged, and symbols 18, which denote the heating in the vehicle interior (not shown), are also depicted. The air conditioning system 12 includes, among other things, an evaporator 20, a radiator 22, a fan 24, and the electric heating device 12. Outside air, represented by an arrow 26, enters the evaporator 20 and exits as cold air, represented by an arrow 28. The cold air 28 is heated in the electric heating device 12 and, via the radiator 22, is directed as warm air, designated by arrows 30, into a flow channel system 32 and from there to an outlet area 34 in the vehicle interior.

[0034] Fig. 2 relates to an electric heating device 35 according to the prior art. The heating device 35 has a heating unit 36 ​​and corrugated fins 38, wherein the heating unit 36 ​​has heating elements 40, which can, for example, be designed as PTC heating elements. The heating elements 40 are described in various embodiments according to the prior art in the following Fig. 3 to 7 are described in more detail.

[0035] The corrugated fins 38 can optionally be provided with gills. A heating network 42 consisting of heating elements 36 is arranged in a frame 44 and fixed and secured therein by tensioning the heating unit 36 ​​over a spring or by gluing it in place. The heating device 35 shown can be a low-voltage heating device, typically operated at a voltage of less than 60 V.

[0036] Fig. Figure 3 shows a schematic representation of an embodiment of the heating unit 36 ​​according to the prior art. The one in the right half of the Fig. The embodiment 46 shown in Figure 3 is a low-voltage heating unit 46 for a supply voltage < 60 V. The one in the left half of the Fig. The embodiment 48 shown in Figure 3 relates to a high-voltage heating unit 48 for a connection voltage > 60 V. Both embodiments 46 and 48 have PTC heating elements.

[0037] First, the low-voltage heating unit 46 will be described. The heating unit 46 has corrugated fins 50 and heating elements 52. The heating unit 46 is formed from alternately arranged corrugated fins 50 and heating elements 52 arranged between the corrugated fins 50. A contact plate 54 is arranged between each of the corrugated fins 50 and the adjacent heating element 52, so that each heating element 52 is surrounded on both sides by contact plates 54. The corrugated fin 50 is in the upper part of Fig. Figure 3 shows a sectional view. The corrugated fin 50 is preferably made of aluminum and has the shape of a series of "Vs", which is why it is also referred to as a V-fin 50. The V-fin 50 is characterized by a small, rigid radius r and forms a small, point-like contact area. This small contact area is compensated for by the contact plate 54, which increases the contact area of ​​the V-fin 50 with the heating element 52. The contact element 54 is a contact plate 54 and is typically made of aluminum, which has a thermal conductivity of approximately 200 mW / mK. The heating element 52 typically has a thermal conductivity of approximately 20 W / mK.

[0038] In contrast, the high-voltage heating unit 48 has electrical insulation 56 and a sheathing tube 58 surrounding the heating element 52 and the insulation 56, which acts as a protective shell. The associated corrugated fin 50 is also designed as a V-fin 50 and likewise has a small, rigid radius r. In the high-voltage heating unit 48, the contact element 54 is arranged between the insulation 56 and the heating element 52. The radius r rests directly against the sheathing tube 58. The insulation 56 can be designed as an insulating layer, an insulating film with a thermal conductivity of 5 W / mK, or as insulating ceramic with a thermal conductivity of approximately 20 W / mK. The sheathing tube 58 is typically made of aluminum with a thermal conductivity of approximately 200 W / mK.

[0039] The fixing of the corrugated rib 50 to the contact element 56 in the low-voltage heating unit 46 and to the sheathing tube 58 in the high-voltage heating unit 48 is in each case achieved by means of bonding, as shown in Fig. 4 is shown.

[0040] Fig. Figure 4 represents the low-voltage heating unit 46 and the high-voltage heating unit 48. In the bonding process for fixing the corrugated rib 50 to the contact element 54 or the sheathing tube 58, an adhesive 60 is precisely, and in particular with pinpoint accuracy, positioned on a contact surface 62 or contact point 62. The corrugated rib 50 is then preferably pressed onto the contact plate 54 or the sheathing tube 58, depending on the embodiment. The adhesive 60 spreads in a thin adhesive layer 64 between the corrugated rib 50 and the contact plate 54. The adhesive layer 64 can compensate for minor irregularities in the contact plate 54.

[0041] Fig. Figure 5 shows a slightly enlarged view of the connected corrugated rib 50 with the formed adhesive layer 64. Identical parts are designated with the same reference numerals. A problem with this arrangement is that the contact plate 54 is necessary to conduct the heat from the PTC ceramic 52, with the contact plate 54 essentially acting as a distribution plate. Furthermore, the contact area 62 of the V-rib 50 on the contact plate 54 is very small due to the small radius of r < 0.5 mm. This places very high demands on the flatness of the contact element 54 or the sheathing tube 58 in the area of ​​the contact point 62. Due to the rigid radius, it is also not possible to increase the contact area between the corrugated rib 50 and the contact element 54 or on the sheathing tube 58 at the contact point 62. For example, gaps or unevenness can only be partially filled with adhesive 60, so that the contact area 62 at the contact point is often further reduced.Furthermore, a problem with the high-voltage heating unit 48 is that it can be crushed if the contact pressure for fixing the corrugated rib 50 to the casing tube 58 has to be too high in order to achieve the bond. This in turn can lead to only a point contact area 62 being created.

[0042] Fig. 6 and Fig. Figure 7 shows a schematic representation of an embodiment of a heating unit 65 as a thick-film resistance heating element 66 with a thick-film resistance layer 68. The heating element 66 has a distribution plate 72 arranged on a finned profile 70, which serves for the direct heat dissipation from an insulating ceramic 74 on the finned profile 70. Top left in Fig. Figure 6 shows the heating element 66 with two fin profiles 70. The fin profile 70 is also shown in an oblique view. A top view of the resistive track 68 with the insulation 74 is shown on the right side of the figure. Fig. Figure 6 shows a first connection 73 and a second connection 75 for connecting the heating element 66. The upper illustration of the heating element 66 shows that the electrical resistance tracks 68 are applied to one of the insulating ceramics 74. The insulating ceramic 74 also serves to insulate the heating element 66 from the outside.

[0043] A problem with this embodiment of the heating unit 65 is that the distribution plate 72 is necessary to conduct heat from the heating ceramic 74. The thermal conductivity of the insulating ceramic 74 is approximately 20 W / mK. Due to its small radius r, the corrugated fin 68 of the fin profile 70 has only a very small contact area with the distribution plate 72, which acts as the contact plate 72. This can lead to local overheating of the heating ceramic 74 and to thermal stresses. Overall, this results in an uneven temperature distribution on the insulating ceramic, which can lead to breakage of the insulating ceramic 74 and / or the heating ceramic 74 as a whole if mechanical stresses occur. In general, any mechanical stress on the heating unit 65 is therefore very problematic. The corrugated fin 68 of the fin structure 70, with its small radius, offers little strength to prevent bending of the heating ceramic 74.

[0044] Fig. Figure 8 shows a cross-sectional view of an assembly of a corrugated rib 50 according to the prior art, a trapezoidal rib 76 according to the invention, and an omega rib 78 according to the invention. Furthermore, it shows Fig. 8 the V-rib 50, the trapezoidal rib 76 and the omega rib 78 each on the contact point 54 in the prior art and a contact surface 79 for the embodiment according to the invention. In the prior art, the adhesive layer 64 is formed on the entire contact element 54. In the trapezoidal rib 76 according to the invention, however, an adhesive layer 82 is arranged between each pair of surface elements 80 of the trapezoidal rib 76. The surface element 80 in between lies flat against a contact surface 84. Thus, direct contact between the trapezoidal rib 76 and the contact element 79 is enabled. The contact surface 84 can be a contact plate 84 made of aluminum or, alternatively, a PTC heating element 90 made of ceramic in a low-voltage version of the heating unit 86 according to the invention, which is Fig. Figure 9 is shown. In a high-voltage version, the contact surface 84 is formed directly on the insulating ceramic or on the heating ceramic.

[0045] The trapezoidal rib 76 and the omega rib 78 both have a large radius r T on, where the radius r T is deformed. The corrugated rib 76, 78 according to the invention has a deformable radius 88 in its uninstalled state. The deformable radius 88 in its installed state in the heating unit 86 preferably has the flat surface element 80. In the manufacturing process of the heating unit 86, the deformable radius 88 can be clamped to the heating element 90 by an external spring or bonded, as is done in Fig. Figure 8 is shown. By applying a contact pressure, the initial radius of the wave rib 76, 78 is deformed so that the deformed radius 88 is formed.

[0046] Fig. Figure 9 shows the heating unit 86 in two different section planes. The left half of Fig. Figure 9 shows the heating unit 90 as a sectional view in the xy-plane of a ribbed profile 92 and the right half of Fig. Figure 9 shows the heating unit 90 in a plane perpendicular to the xy-plane, in which trapezoidal ribs 76 and omega ribs 78 are visible. The rib arrangement 92 optionally features gills. In the right part of Fig. 9 in the right-hand section represents the trapezoidal rib 76 and the omega rib 78, which already correspond to the illustration in Fig. The large contact surface 80 described in section 8 is formed. An adhesive surface 94 is formed outside each contact surface 80. In the case of the trapezoidal rib 76, the adhesive surface 94 is formed between the contact surfaces 80. In the case of the omega rib 78, the contact surfaces 80 are located next to each other. The adhesive is arranged outside the contact surfaces 80 as an adhesive surface 94 at the right and left edges of the omega rib 78. Compared to the trapezoidal rib 76, the omega rib 78 has a larger contact surface 80 overall. Here, the contact element 84 or the contact plate 84 no longer functions as a heat distribution plate, but serves for the electrical contacting of the heating unit 86. The heating element 90 is, for example, a PTC heating element 90. The heating unit 86 in the Fig. The embodiment shown in Figure 9 is a low-voltage heating unit 86.

[0047] Fig. Figure 10 shows another embodiment of a heating unit 96 in two different section planes. The left half of Fig. Figure 10 shows the heating unit 96 as a sectional view in the xy-plane of a ribbed profile 98 and the right half of Fig. Figure 10 shows the heating unit 96 in a plane perpendicular to the xy-plane, in which trapezoidal ribs 76 and omega ribs 78 are visible. The heating unit 96 has no contact element. The trapezoidal rib 76 forms the contact surface 80 directly on a heating element 99. The rib 76 and / or 78 serves here as a heat distribution element and as a contact electrode 100. Due to the stable shape of the trapezoidal rib 76 and the omega rib 78, they can assume the function of the contact plate. The heating unit 96 has no contact element. The ribs 76 and / or 78 are directly electrically contacted.

[0048] Fig. Figure 11 shows a schematic representation of a heating unit 102 in a representation in the xy-plane (left part of Fig. 11) and a plane perpendicular to the xy-plane (right part of Fig. 11) The heating unit 102 is an embodiment of a high-voltage heating unit 102 comprising a heating element 104, a fin arrangement 106, a sheathing tube 108, insulation 110, which may be designed as an insulating layer or insulating film, and a contact element 112 arranged between the heating element 104 and the insulation 110. A contact surface 114 is provided as in the embodiments of Fig. 9 and Fig. The heating element 102 is designed as a large contact surface 114 and lies directly against the outer tube 108. An adhesive strip 116 is formed outside the contact surfaces 114 and is optional. A silicone adhesive, for example, can be used. The heating unit 102 is characterized by the fact that the contact surface 114 is formed between the outer tube 108 and a deformed fin radius 118. This allows for improved heat extraction from the heating element 104, which is preferably a PTC heating element 104. The heat extraction occurs from the PTC element 104 via the contact element 112, the insulation 110, the outer tube 108, to the fin 76 or 78, depending on the type of fin used: trapezoidal fin 76 or 78 (omega fin). An adhesive strip 116 is only visible in the spaces between the contact surfaces 114. The adhesive can also be omitted entirely. A spring is used to fix the rib 76 or 78 to the sheathing tube 108.By compressing the trapezoidal rib 76, an omega rib 78 with an enlarged contact surface 114 can be created. This also overcomes a disadvantage present in V-ribs 38 or 50 used in the prior art, and despite compression of the sheathing tube 108, a flat contact surface of the rib 76 or 78 on the sheathing tube 108 can be achieved. The sheathing tube 108 forms the contact surface with the rib 76 or the rib 78.

[0049] Fig. Figure 12 shows a schematic representation of another embodiment of a high-voltage heating unit 118 in a representation in an xy-plane (upper part of Fig. 12) and in a representation perpendicular to the xy-plane (lower part of Fig. 12) A rib arrangement 120 is arranged alternately with a heating element 122. The heating element 122 comprises a PTC heating element 122 with a contact element 124 and electrical insulation 126. A contact surface 128 is arranged directly on a surface of the insulation 126. Optionally, an adhesive 130 can be provided outside the contact surfaces 128 to fix the rib arrangement 120 to the heating element 122. The rib arrangement 120 can have a trapezoidal rib 132 and / or an omega rib 134. In particular, in the heating unit 118 with the omega rib 134, the contact element 124 can be omitted. Here, the omega rib 134 can function as a heat distribution plate.

[0050] Fig. Figure 13 shows a high-voltage heating unit 136 with a thick-film resistance heating element 138, which is at least partially surrounded by electrical insulation 140. The insulation element 140 is preferably a ceramic insulation element 140. A contact surface 142 of a trapezoidal rib 144 or an omega rib 146 is arranged directly on the insulation element 140. Since the contact surface 142 of the trapezoidal rib 144 and the omega rib 146 are planar, a heat distribution plate is not required. The planar design of the contact surface 142 and the high stiffness of the trapezoidal rib 142 and / or the omega rib 144 can prevent bending and / or breakage of the insulating ceramic 140, even under mechanical stress on the heating unit 138. The heating unit 138 has an optimized number of components.

[0051] Fig. Figure 14 shows a schematic representation in a perspective view of a heating unit 146 with a corrugated fin arrangement 148, in particular a trapezoidal fin arrangement 148 on both sides of a heating ceramic 150 with connection elements 152. The lower part of Fig. Figure 14 shows the heating ceramic 150 of the heating unit 146 without the rib arrangement 148. In a heating device according to the invention (not shown), heating units 146 and heating ceramics 150 are preferably arranged alternately.

[0052] Fig. Figure 15 shows a top view of the heating unit 136 in the upper part. Fig. 14. In the lower part of Fig. Figure 15 shows an arrangement of corrugated ribs 154 in perspective view. The middle part of Fig. Figure 15 shows an enlarged section of the arrangement of corrugated ribs 154. Each corrugated rib 154 has a height 156, which is denoted by R. H is designated, and a width of 158, which is labelled with R Dis designated, as well as a rib depth of 160, which is labelled with R T The rib 154 is deep-waved, meaning it has a depth of 162 and does not include gills. The depth of 162 increases heat transfer between the rib 154 and the air. The corrugated rib 154 is oriented according to the airflow, allowing the air to pass along or substantially parallel to the rib depth 160.

[0053] Fig.Figure 16 shows the high-voltage heating unit 146 in a side view (top) and as a top view (middle and bottom). A corrugated fin 154, forming the fin arrangement 148, is arranged on each side of the heating ceramic 150. The fin height 156 is essentially perpendicular to the plane of the heating ceramic 150's extension direction. In the top view (middle and bottom) of the heating unit 146, the corrugation depth 162 of the fin 154 is visible. The fin can be mechanically clamped (middle) or bonded (bottom) to fix it to the heating ceramic 150. Due to the high stiffness of the fin 154, which can be configured as either a trapezoidal fin 132 or an omega fin 134, breakage of the heating ceramic 150 is prevented even under mechanical stress. Due to the large contact area of ​​the large base 128, no local temperature differences can occur on the ceramic 150. The heat can be distributed evenly. This prevents thermoelectric stresses.

Claims

[1] Heating device (12) for a motor vehicle, comprising an electric heating unit (86, 96, 102, 118, 136, 146) having heating elements (90, 99, 104, 122, 138, 150), and a corrugated fin arrangement (92, 98, 106, 120, 146, 148) having corrugated fins (76, 78, 95, 97, 109, 111, 132, 134, 144, 148, 154), characterized by , that the corrugated fins (76, 78, 95, 97, 109, 111, 132, 134, 144, 148, 154) form a deformed radius (88, 108), wherein a large contact area (79, 114, 128, 142) is formed between the heating elements (90, 99, 104, 122, 138, 150) and the corrugated fins (76, 78, 95, 97, 109, 111, 132, 134, 144, 148, 154), wherein the large contact area (79, 114, 128, 142) of the corrugated fins (76, 78, 95, 97, 109, 111, 132, 134, 144, 148, 154) has a planar section (80) and wherein the deformed radius (88, 108) is a contact radius (88, 108) with r T>0.5 mm, wherein the corrugated rib (76, 78, 95, 97, 109, 111, 132, 134, 144, 148, 154) is designed as a trapezoidal rib (76, 95, 109, 132, 144) or as an omega rib (78, 97, 111, 134, 148), and wherein the corrugated ribs (76, 78, 95, 97, 109, 111, 132, 134, 144, 148, 154) are fixed by means of gluing, wherein in the case of the trapezoidal rib the adhesive surface is formed between the contact surfaces and in the case of the omega rib the contact surfaces are located next to each other and the adhesive is arranged outside the contact surfaces as an adhesive surface at the edge of the omega rib. [2] Heating device (12) according to claim 1, characterized by , that at least one heating element (90, 99, 104, 122, 138, 150) is a PTC heating element (90, 99, 104, 122, 150). [3] Heating device (12) according to one of the preceding claims 1 or 2, characterized by, that the at least one heating element (90, 99, 104, 122, 138, 150) is a resistance heating element (138, 150), in particular a thick-film resistance heating element (138). [4] Heating device (12) according to any one of the preceding claims 1 to 3, characterized by , that a contact element (79, 84, 112, 124) and an insulating element (110, 126, 140) are provided. [5] Heating device (12) according to any one of the preceding claims 1 to 3, characterized by , that an insulating element (110, 126, 140) is provided. [6] Heating device (12) according to one of the preceding claims, characterized by , that the corrugated ribs (76, 78, 95, 97, 109, 111, 132, 134, 144, 148, 154) exhibit high stiffness. [7] Heating device (12) according to any of the preceding claims, characterized by , that the heating elements (90, 99, 104, 122, 138, 111, 150) can be fixed by means of gluing.

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