DE102006036364A1 - Warm air heating system for motor vehicle interiors has PTC heating elements in contact with multiple U-section fins through which air is passed - Google Patents

Abstract

The assembly comprises a fan (8) and cylindrical heater construction having positive temperature coefficient (PTC) heating elements (10) arranged in a ring with a number of inverted U-section fins (19) bound in a circular pattern with flat sections (20) in close contact with the heating units which have electrical contacts (12,14).

Description

The The invention relates to an electric heating module according to the preamble of claim 1. This heating module is in particular for air flow heating in Vehicles, such as motor vehicles and aircraft provided. It exists essentially of at least one PTC heating element and at least an adjoining, air-permeable heat-dissipating area with heat-conducting Slats that are in operative connection with the PTC heating element. The PTC heating element is in one with the heat-conducting fins Framework to a module summarized. The thermally conductive fins contain Heat transfer sections, the heat conducting on the PTC heating element rest. Alternatively or in addition can they also rest on a contact element heat-conducting, which is attached to the PTC heating element and that for the operation of the PTC heating element necessary electricity leads. Within the frame, a spring element is provided which the heat transfer sections the heat-conducting Blades pressed against the PTC heating element or the contact element. So is a good heat extraction from the PTC heating element into the heat-conducting Ensures slats.

PTC elements are semiconductor resistors made out Ceramic whose resistance to resistance is temperature-dependent. The resistance-temperature characteristic behave Nonlinear: The resistance of a PTC heating element decreases rising component temperature initially light, then at a characteristic temperature (reference temperature) to rise very steeply. This overall positive course of the resistance-temperature characteristic (PTC = Positive Temperature Coefficient) causes a PTC heating element has self-regulating properties. At a component temperature, which is significantly lower than the reference temperature, has the PTC heating element a low resistance, so that correspondingly high currents are passed can. If for a good heat dissipation of the surface of the PTC heating element is taken care of, so a corresponding amount of electrical power is absorbed and as heat issued. However, if the temperature of the PTC heater rises above the reference temperature, As the PTC resistance increases rapidly, the electrical power consumption increases a very small value is limited. The component temperature is approaching then an upper limit, which depends on the heat absorption the environment of the PTC heating element. Under normal environmental conditions, the component temperature of the PTC heating element so not over a characteristic highest Temperature rise, even if the desired heat dissipation in case of failure completely interrupted becomes. This and the self-regulating properties of a PTC heating element, due whose recorded electrical power exactly the delivered corresponds to thermal power, predestined PTC heating elements for use in heating or air conditioning systems of vehicles or other applications of airflow heats in vehicles. Because for safety reasons may in this application area even in case of failure no flammable Temperatures in the heating element arise, but nevertheless in normal operation a high heating capacity is required.

For the interior heating of motor vehicles, it is already known to use electric heating modules with a frame that combines a plurality of PTC heating elements and adjoining, heat-permeable heat-dissipating areas with heat-conducting fins to form a module. An example of such known electric heating modules can be found in the EP 0 350 528 A1 , The well-known heating module described therein consists of several layers of flat juxtaposed with its narrow side in the air flow PTC heating elements, which are electrically contacted on their flat tops and their lower sides with contact plates. The adjacent thereto heat dissipation areas have meandering arranged metal fins, which are also with their narrow side in the air flow and thermally contact on their broadside the Kontaktierungsbleche the PTC heating elements at regular intervals for a heat transfer. In order to achieve a good heat extraction from the PTC heating elements, the heat-conducting fins and thus in the air flow, a wavy bent, biased sheet is used as a spring element in the frame whose elastic spring force alternately arranged heat dissipation areas with heat-conducting fins and the webs with the PTC heating elements pressed together.

Another example of such a known construction of an electric heating module of the type mentioned is in the EP 1 432 287 A1 described. The electric heating module disclosed there with PTC heating elements contains a spring element as a flat sheet with elastically bent openings, which provide the contact pressure between the heat-conducting fins and the webs with the PTC heating elements.

Due to the necessarily very thin design of the heat-conducting fins, which are arranged with their broad sides meandering between two webs with PTC heating elements or between such a web and the frame, the spring force of the spring element must be defined defined. Otherwise there is a risk of unintentional plastic deformation the heat-conducting lamellae. On the other hand, the spring force must not be too small, otherwise the heat transfer from the PTC heating elements in the heat-conducting fins is not optimal. This requires high production engineering requirements in the production of the usually for the present application specially to be made spring elements and appropriate care in assembling the heating module.

Of the The present invention is based on the object, a electric heating module of the type mentioned in terms of To simplify or improve spring element.

This is solved Task by an electric heating module with the features of claim 1. Preferred embodiments and further developments of the invention are in the claims 2 to 16 laid down.

To The present invention is an electric heating module of the above so called type improved so that the spring element now made of soft elastic material, in particular an elastomer. Within the scope of the invention So the most diverse, quite normal commercially available soft elastic materials, such. As rubber or soft elastic plastics be used, wherein the spring force significantly from the selected material and its material thickness depends and therefore to their manufacture in the manufacture of the heating module no special requirements are made. It's just a selection of suitable materials for a specific heating module model to meet the requirements - on the one hand not too small and on the other hand not too big Spring force - too fulfill. Another advantage of the spring element according to the invention is that this is neither electrically nor thermally conductive. This enlarges the Travel for different arrangements of the items of the heating module.

in the Under the invention, the electric heating module with a Be equipped frame that at least partially made of soft elastic Material, for example rubber. This soft-elastic area Such a frame may then be formed by a suitable shaping thereof assume the function of the spring element. This considerably simplifies the production of the electric heating module, since an otherwise separately present component is saved.

Special Advantages arise in the context of the present invention, when the frame of the heating module is separable, in a parting plane, which is approximately perpendicular to the direction of flow of the heat dissipation area runs, So not, as hitherto in the prior art exclusively the case, in a direction of flow the heat release area parallel plane. The (separate or by part of the frame formed) spring element is arranged in the frame so that the Contact pressure of the heat transfer sections of thermally conductive Slats on the PTC heating elements and the contact elements substantially parallel to the direction of the air flow. The thermally conductive Slats and the PTC heating elements can then be in one half of the Frame are used and the frame then by simply putting on the other half be closed without risk of the heat-conducting fins due to excessive forces, in particular, too high a spring force to be deformed. Because the heat-conducting lamellae run with their broad sides parallel to the air flow, so that they easily flowed through by these are. The contact pressure acts in the present preferred separability the frame in contrast so on the narrow sides of the slats, since he is also parallel directed to the air flow. Point in the direction of their narrow sides the heat-conducting Slats, however, naturally the highest stability. hereby not only can the contact pressure for better heat transfer be increased, but it is especially possible for the first time, an electric heating module with PTC heating elements fully automatically assembled by machine.

For a machine Fabrication of the present electric heating module, it is preferred if arranged the spring element in the region of the parting plane of the frame is.

The thermally conductive Slats are preferably made of U-profiles, whose U-back the heat transfer sections form. The contact pressure of the spring element then continues to act on the narrow sides of the air-flow fins formed by the U-legs, which have a very high stability in this direction, while the U-back of the U-profiles run perpendicular thereto and an advantageously large contact surface of the thermally conductive Form slats on the PTC heating element or its contact element.

The U-legs of the heat-conducting Slats can in this case with surface structuring, in particular bead-like structures for steering and in particular for swirling be provided of the air flow. The generation of eddies in the air stream improved at such surface structuring the convective heat conduction in the air stream and thus the heat extraction from the slats in the airflow.

Of the Frame may be provided with airflow streaming webs, so that by a suitable air flow guide the heat extraction in the air flow can be improved again.

At the just mentioned flow guiding Stegen can concentrically arranged guide rings be arranged in the air flow. Depending on the application, it can be very Be beneficial, these guide rings to be tilted out of the axial plane, in particular in a concentric, conical shape, so that the air flow to the guide rings when flowing out radially outward is deflected or if the guide rings in the inflow area of the fan heater are arranged, is deflected in the axial direction. In addition to Effect of air flow guidance, the depending on the application of the appropriate air flow deflection Benefits, can have a concentric conical shape of guide rings the risk of foreign bodies entering the air flow channel reduce.

Of the basic structure of the electric heating module according to the invention may provide that multiple PTC heating elements circumferentially distributed around a heat release area are arranged, for example in a circular shape. Alternatively or additionally For example, the at least one PTC heating element may be in the center of the heat dissipation area be arranged. These two arrangement options are special advantageous if the frame of the heating module in a perpendicular to Air flow direction lying plane is divisible and the contact pressure of the heat-conducting Slats on the PTC heating elements axially, ie parallel to the direction of air flow runs. Because in this case it makes sense to arrange the PTC heating elements so that their broadsides also substantially perpendicular to the air flow direction run; They are therefore equally "transversal" in the air flow first not optimal, so that the arrangement of the PTC heating elements on the outer edge of the heat-conducting Lamellas circumferentially distributed, circular or in the form of an n-corner, the possibility offers, the PTC heating elements outside of the flow area to arrange the heating module. At the same time are the PTC heating elements then also arranged at the one place where the two frame parts clash and thus the highest contact pressure on this Create a spot. Placing a PTC heating element in the center of the heat dissipation area is then not disadvantageous if the heating module according to the invention with a fan is combined, which is arranged directly before or after the heat release area is. Because such a fan is usually provided with an arranged in the axis of rotation motor, the Heat-dissipating area the heating module shaded anyway at this point.

A annular Training the heat delivery area is for the present electric heating module is particularly preferred, though Other forms, such as the conventional rectangular shape feasible are. The thermally conductive Slats can then as a continuous lamellar ring be prefabricated, which is the mechanical production of the heating module according to the invention again considerably simplified. The spring element can then off a sealing ring, such as a commercially available O-ring exist, and to avoid excessive contact pressures this Sealing ring by introducing circumferentially distributed recesses can be modified.

The annular Arrangement of the heat dissipation area with its heat-conducting Slats, which are preferably arranged substantially radially extending are, allows, that the inventive electrical Heating module in a streamlined cylindrical air flow channel or a corresponding tube can be used, wherein a very even flow through the Heat output range without formation of hot Areas such as In the corners of a conventional rectangular heating module arise, is guaranteed. This increases not least the efficiency of the PTC heating elements used. The radially extending arrangement of the heat-conducting fins allows a flow the same not only in the axial direction, but with an additional radial velocity component of the air flow, so that the Slats are not only one-dimensional, but two-dimensional flows through. This also increases turn the efficiency of heat extraction in the airflow.

In front everything is a ring trained heating module, however, for efficient combination with a Axial or diagonal fan suitable for what preferably a fan housing on the frame attached or integrally formed on this. The axial or diagonal fan Can be used together with the heating module as overheating-safe fan heater this being a previously unprecedented flat construction has, for example, for insertion into ventilated vehicle seats suitable to form the seat heating.

embodiments for a Heating module according to the invention will be described in more detail below with reference to the accompanying drawings and explained. Show it:

1 a perspective view of a first embodiment of a heating module according to the invention with fan;

2 the embodiment 1 in an exploded view;

three the embodiment 1 in a perspective from below;

4 an exploded view of a second embodiment of a heating module according to the invention with fan;

5a . 5b a perspective and a plan view of a laminated ring in a first embodiment;

6a . 6b a perspective and a plan view of a laminated ring in a second embodiment;

7a . 7b . 7c a perspective from above, from below and a plan view of a third embodiment of a laminated ring;

8a . 8b a perspective and a plan view of a fourth embodiment of a laminated ring;

9a . 9b a perspective and a plan view of a fifth embodiment of a laminated ring.

In the 1 to three a first embodiment of an electric heating module according to the invention is shown, which is combined with an integrated fan to a fan heater. A frame 1 is integral with a fan housing 2 connected, both of which have a substantially cylindrical For tion and form in its interior a streamlined cylindrical channel for the air stream to be heated. The frame 1 is divided into two parts and consists of a top part three as well as a lower part 4 , which are in a radial parting plane 5 sit on each other and snap hooks 6 be held together. In the discharge area of the illustrated device, the frame 1 Stege 7 on, which extend into the air flow and lead this. The fan housing 2 includes a diagonal fan 8th that with mounts 9 on the fan housing 2 is attached. With the diagonal fan 8th it is a commercially available fan with centrally arranged (not shown here) electric motor. To look at the fan 8th to release is in 2 the fan housing 2 shown partially cut.

Downstream of the diagonal fan 8th are in the parting plane, but outside the cylindrical flow channel annular around this six PTC heating elements 10 , on a lower ring plate 11 glued on, arranged. Above is an upper ring plate 12 made of aluminum on the PTC heating elements 10 placed to contact them electrically and thermally. The upper ring plate 12 returns those from the PTC heating elements 10 decoupled heat to a lamellar ring 13 Further, which forms an inventively annular heat dissipation area by extending its individual fins radially towards the center into the cylindrical air flow channel.

The assembly of lower ring plate 11 , PTC heating elements 10 , upper ring plate 12 and lamellar ring 13 is between the shell three and the lower part 4 of the frame 1 held. This is in the lower part 4 of the frame 1 a recording 17 intended. For efficient heat transfer from the broad sides of the PTC heating elements 10 over the upper ring plate 12 on the lamellar ring 13 is a high contact pressure is essential. This is made by a soft elastic spring element 14 , here by milling in recesses 15 made of a commercially available O-ring seal, guaranteed. Because this generates in conjunction with the snap hooks 6 a contact force between the lamellar ring 13 and the upper ring plate 12 as well as between the upper ring plate 12 and the PTC heating elements 10 ,

As based on 2 can be clearly seen, the contact force acts in contrast to the prior art in the axial direction of the slats of the heat dissipation area, ie parallel to the air flow. Since in this way the narrow sides of the lamellae are subjected to the contact force, due to their higher stability in this direction, they can cope with larger tolerances in the contact force, so that a machine assembly of the illustrated fan heater is possible without difficulty. The possibility for mechanical production is further supported by the fact that for the spring element 14 a seal seat 16 in the lower part 4 of the frame 1 is provided, and that the two ring plates 11 . 12 one contact tongue each 18 Wear that with composite frame 1 protrude from this and for electrical contacting of the PTC heating elements 10 can be used.

The use of a diagonal fan 8th and the arrangement of the lamella ring 13 , that is, the air-throughable heat release area downstream of the diagonal fan 8th as well as the corresponding shaping of the upper part three of the frame 1 causes the lamellar ring 13 flows through not only axially, but also with a diagonal component from the inside out. The radial arrangement of the U-profiles 19 existing individual slats of the lamellar ring 13 supports this air duct. However, the slats do not consist of continuous U-profiles 19 ; Rather, the U-back is present only on the radially outer side and forms there heat transfer sections 20 with which the lamellar ring 13 on the upper ring sheet 12 rests and by means of the spring element 14 on the ring plate 12 is pressed on.

That in the 1 to three illustrated embodiment represents a particularly compact, yet efficient fan heater, with its PTC heating elements 10 self-regulating, safe and very fast reacting enables efficient heating, for example, of ventilated motor vehicle seats. By switching off the PTC heating elements, the fan heater can optionally serve as a cooling fan. The arrangement shown with an annular heat dissipation area and a diagonal fan connected in front, which can of course also be an axial fan, at the same time ensures that a high volume of air with low power consumption of the fan 8th can be passed with advantageously low outflow speeds.

Based 2 be added that the fan housing 2 can also be releasably attached to the frame. It is also conceivable that at least the frame 1 made of soft elastic material, such as hard rubber, so that with a corresponding shape of the recording 17 or one from the frame 1 inwardly retracted housing lip on the separate spring element 14 can be omitted, since the spring force from the frame 1 or a corresponding lip is generated.

Of course it is also possible, the heat dissipation area and thus the lamellar ring 13 upstream of the fan, so to arrange in its laminar Anströmzone. An appropriate structure is in the 4 as a second embodiment in an exploded view. The case used here 1 again consists of a shell three and a lower part 4 , where the top part three at the same time as a fan housing 2 for an axial fan 21 serves. The lower part 4 of the frame 1 is here at the top three by means of locking tabs 22 and corresponding latching projections 23 established.

This in 4 shown second embodiment of a fan heater shows in addition to the "reverse" arrangement of heat dissipation of the heating module and fan another modification; The annular assembly consisting of four PTC heating elements 10 which this supporting lower ring plate 11 , the upper ring plate 12 and the soft-elastic and thermally and electrically insulating spring element 14 this time is not located outside of the approximately cylindrical flow area, but so that the heat transfer sections 20 the lamellae of the lamellar ring 13 lie in the radial direction approximately centrally in the annular flow area. This is the recording 17 in the lower part 4 of the frame 1 approximately in the middle of the inflow area of the axial fan 21 arranged sucked air. The advantage of this arrangement of the heating element assembly is that of the PTC heating elements 10 decoupled heat very quickly and evenly over the entire lamellar surface of the lamellar ring 13 distributed. Furthermore, so will the annular assembly with the PTC heating elements 10 flows directly around the air flow, so that an additional heat extraction takes place in the air flow into it. This is very advantageous due to the resistance-temperature characteristic of a PTC heating element and leads to a higher efficiency of the heating module.

The lower ring plate 11 and the upper ring plate 12 each have a contact tongue 18 pointing toward the center of the cylindrical air flow passage to be contacted together with the fan motor (not shown).

Correspondingly, other modifications of the embodiments shown are possible. Thus, for example, the central region of the cylindrical flow channel, which is already shaded by the fan motor, be used to arrange a round or more star-shaped or otherwise arranged PTC heating elements. This may also be in addition to an outer PTC heating element ring in the in 1 to three be combined type shown. It is also possible to arrange both an upstream and downstream of a fan, an electric heating module according to the present invention, or vice versa upstream and downstream of a fin ring to insert a respective fan. Of course, an inventive electric heating module can also be combined with a radial fan.

The 5 to 9 finally show different embodiments of laminated rings 13 , both in their production technology as well as in the respective radial position of the heat transfer sections 20 differ.

In the 5a and 5b is a lamellar ring 13 shown, consisting of individual U-profiles 19 which is substantially radial, is composed. For this are the U-profiles 19 radially inward with laser welding points 24 mechanically as well as thermally connected. The U-backs 25 the U-profiles 19 extend only over a radially outer portion and form the heat transfer sections 20 for thermal contacting of the PTC heating elements 10 or the lower or, depending on the embodiment, the upper ring plate 11 . 12 ,

In the 6a and 6b is a very similar structure of a lamellar ring 13 by U-profiles 19 shown. The U-backs 25 the U-profiles 19 Again form the heat transfer sections 20 but these are facing up and are intended for use upstream of a fan. At the same time are the U-profiles 19 with beads 26 on the one hand to increase their stability in the axial direction (which is a higher contact pressure on the PTC heating elements 10 or the corresponding ring plate 11 . 12 allows), and on the other hand, the air passing through the lamellar ring 13 flows, in addition to swirl, resulting in better heat transfer from the fins 19 into the air stream.

The lamellar ring 13 in the 7a . 7b and 7c is shown, does not consist of a plurality of individually manufactured slats or profiles, but of a folded form sheet. Accordingly, the here again radially outer heat transfer section 20 who no longer made single U-backs 25 is formed, formed continuously in the circumferential direction, resulting in a higher heating power of the PTC heating elements 10 allows, as the heat extraction in the laminar ring 13 is higher. Based 7b You can also see very well that the lamellar ring 13 Is formed axially graduated in the radial direction.

The in the 8a and 8b shown lamellar ring 13 again consists of individual U-profiles 19 by means of welding points 24 mechanically and thermally interconnected. Unlike in the 5a and 5b shown lamellar ring 13 Here are the U-backs 25 the U-profiles 19 arranged radially inwardly and do not continue radially outward, but form the heat transfer sections 20 for direct or indirect contacting of the PTC heating elements 10 , This lamellar ring 13 So it is suitable for use in an electric heating module in which the PTC heating elements 10 are arranged centrally inside.

In the 9a and 9b Finally, the lamellar ring 13 out 4 shown. It in turn consists of a plurality of U-profiles 19 that over weld points 24 mechanically and thermally interconnected, in turn, the U-back 25 not over the entire length of the U-profiles 19 extend, but extend radially only as far as it to form the heat transfer sections 20 necessary is. The heat transfer sections 20 are for each U-profile 19 arranged approximately centrally so that the paths for heat conduction in each U-profile 19 are kept advantageously short. In the area of the U-back 25 again four beads each 26 on every U-profile 19 attached so that the U-profiles 19 and thus the lamellar ring as a whole 13 have a high stability.

Claims (16)

Electric heating module for air flow heating, in particular in vehicles, with at least one PTC heating element ( 10 ) and at least one adjoining, air-flowable heat dissipation area ( 13 ) with heat-conducting fins, and with a PTC heating element ( 10 ) and the heat-conducting lamellae ( 13 ) into a module summary framework ( 1 ), wherein the heat-conducting lamellae ( 13 ) Heat transfer sections ( 20 ) mounted on the PTC heating element ( 10 ) and / or on an attached thereto, electrical current leading contact element ( 11 . 12 ) lie in a thermally conductive manner, and wherein within the frame ( 1 ) a spring element ( 14 ) for pressing the heat transfer sections ( 20 ) of the heat-conducting lamellae ( 13 ) to the PTC heating element ( 10 ) and / or the contact element ( 11 . 12 ), characterized in that the spring element ( 14 ) consists of soft elastic material, in particular of an elastomer. Electric heating module according to claim 1, characterized in that the frame ( 1 ) at least partially made of soft elastic material, in particular rubber and a part of the frame ( 1 ) the spring element ( 14 ). Electric heating module according to one of claims 1 or 2, characterized in that the frame ( 1 ) in a direction of the flow of air flowing through the heat release area substantially perpendicular separation plane ( 5 ) is separable, wherein the spring element ( 14 ) is arranged so that the contact pressure of the heat transfer sections ( 20 ) of the heat-conducting lamellae ( 13 ) to the PTC heating element ( 10 ) and / or the contact elements ( 11 . 12 ) runs parallel to the direction of the air flow. Electric heating module according to claim 3, characterized in that the spring element ( 14 ) in the region of the parting plane ( 5 ) of the frame ( 1 ) is arranged. Electric heating module according to at least one of claims 1 to 4, characterized in that the heat-conducting lamellae ( 13 ) made of U-profiles ( 19 ) whose U-backs ( 25 ) the heat transfer sections ( 20 ) form. Electric heating module according to claim 5, characterized in that the U-legs of the heat-conducting lamellae ( 13 ) with surface structuring, in particular bead-like structures ( 26 ) are provided for steering and / or turbulence of the air flow. Electric heating module according to at least one of claims 1 to 6, characterized in that the frame ( 1 ) with streaming webs extending into the airflow ( 7 ) is provided. Electric heating module according to claim 17, characterized in that in the air flow channel at the webs ( 7 ) Conically shaped, concentrically arranged guide rings for the radial deflection of the incoming or outflowing air flow are mounted. Electric heating module according to at least one of claims 1 to 8, characterized in that a plurality of PTC heating elements ( 10 ) circumferentially distributed around a heat release area ( 13 ) are arranged. Electric heating module according to at least one of claims 1 to 9, characterized in that the at least one PTC heating element ( 10 ) in the center of the heat release area ( 13 ) is arranged. Electric heating module according to at least one of claims 1 to 10, characterized in that the heat-conducting lamellae ( 13 ) are prefabricated as a continuous lamellar ring. Electric heating module according to at least one of claims 1 to 11, characterized in that the heat release area ( 13 ) is formed as a substantially circular ring. Electric heating module according to claim 12, characterized in that the spring element ( 14 ) consists essentially of a sealing ring. Electric heating module according to claim 13, characterized in that the sealing ring with circumferentially distributed recesses ( 15 ) is provided. Electrical heating module according to at least one of claims 1 to 14, characterized in that a fan housing ( 2 ) on the frame ( 1 ) is attached or molded on this. Electric heating module according to claim 15, characterized in that in the fan housing ( 2 ) an axial fan ( 21 ) or diagonal fan ( 8th ) sits.