EP2659731B1 - Heat sink and holding body for heating elements, heating apparatus and method for manufacturing a heat sink and holding body - Google Patents

Description

The invention relates to a cooling and holding body for heating elements, in particular PTC heating elements, a heater with such a cooling and holding body and a method for producing such a cooling and holding body. A cooling and holding body for heating elements with the features of the preamble of claim 1 is made DE 10 2006 018 151 A1 and DE 38 16 819 A1 known.

In control cabinets, for example, temperature changes cause the formation of condensation, which together with dust and aggressive lanes can cause corrosion. This increases the risk of business interruptions caused by creepage currents or flashovers. In order to ensure consistently optimum climatic conditions for the proper functioning of the components in the control cabinet, heaters or fan heaters, in particular PTC semiconductor heaters, are therefore used whose reliability and longevity are subject to stringent requirements.

Such cardiac devices are usually equipped with electrical heating elements. The holder of these heating elements should on the one hand allow a good heat transfer and on the other hand a constant secure fixation. The frequent and depending on the operating conditions temperature changes can lead to fatigue due to aging and thus to a reduction in the holding force with which the heating elements are fixed. As a result, the heat transfer is deteriorated. If the hold function is completely eliminated, it can even lead to a total failure of the device.

An example of a known heater with a PTC element is shown in FIG DE 196 04 218 A1 described, in which the PTC element is mounted in a centrally arranged rectangular recess. For attachment is a Double wedge arrangement provided in the recess, which can be moved by means of a screw to change the width of the double wedge assembly. Thus, the PTC element can be jammed in the recess. The double wedge assembly is expensive and does not solve the problem of reducing the clamping force due to material fatigue. To avoid this, the double wedge assembly would have to be adjusted by operating the screw.

An improvement of this known device is in the generic DE 2006 018 151 A1 disclosed to the assignee. In this case, the heating element is arranged in the centrally arranged recess of a heat exchanger, wherein the contact inner surfaces of the recess lie flat against the heating element. The holding force is achieved in that after installation of the heating element sidewalls of the heat exchanger are bent inwardly, whereby the distance between the contact surfaces of the recess is reduced. The arranged between the contact surfaces heating element is thereby clamped flat. This attachment is a stable holder that provides a constant high holding force and thus a constant good heat transfer from the heating element to the heat exchanger without readjustment. The buckling of the side walls, however, leads to a plastic deformation of the wall material, which is not optimal due to the frequent temperature changes for the holding conditions.

The invention is therefore based on the object to improve a cooling and holding body of the type mentioned in such a way that a secure mounting of the heating element or the heating elements in the cooling and holding body is achieved despite frequent temperature changes. The invention is further based on the object to provide a heater with such a cooling and holding body and a method for producing such a cooling and holding body.

According to the invention this object is achieved by the holding and cooling body according to claim 1, the heater according to claim 11 and the method according to claim 12.

The invention is based on the idea of a cooling and holding body for heating elements, in particular electrical heating elements, in particular PTC heating elements indicate that has a Heizelementeaufnahme in which the heating elements are clamped. The Heizelementeaufnahme has a plurality of circumferentially distributed receiving areas, in each of which at least one heating element is arranged. The receiving areas are formed between an outer part and an inner part arranged in the outer part. At least the outer part has a polygonal profile with several corners, which are connected by sides. The receiving areas are arranged in the corners of the polygonal profile. The sides of the polygonal profile are elastically deformed to produce a clamping force, wherein the clamping force acts on the respective heating elements.

In contrast to the known achieved by plastic deformation clamping the heating elements according to the invention, the sides of the polygonal profile are elastically deformed. This means that the deformation takes place in the area of the Hook's straight line and is proportional to the stress that is generated in the polygon profile. The deformation below the elastic limit optimizes the clamping force with which the heating elements are clamped in the receiving areas of the heating element receptacle. Settlements resulting from material aging are avoided in contrast to plastic deformation. The clamping force with which the heating elements are fixed remains constant or at least substantially constant despite the temperature changes. Due to the constant clamping force, a substantially constant heat transfer from the heating elements to the material of the holding and cooling body is achieved. The elastic deformation also causes the force with which the heating elements are pressed acts as a spring force. A readjustment of the pressure or clamping force is not required.

The formation of at least the outer part as a polygonal profile has the advantage that the heating power is increased and a clamping of the heating elements without additional clamping elements is possible. The omission of the clamping elements enables a compact design of the holding and cooling body. In contrast to the prior art, not a single centrally arranged receiving area is provided, but a plurality of receiving areas distributed in the circumferential direction of the outer part. As a result, the heat output in the holding and cooling body is better distributed and allows efficient heat dissipation. By combining the inner part with the polygonal outer part, the installation of the heating elements is simplified. The formation of the outer part has a polygonal profile the further advantage that this can be easily produced, for example by extrusion.

In a preferred embodiment, the corners of the polygonal profile forming clamping surfaces, which are adapted to the shape of the heating elements, in particular flattened, whereby a particularly good heat transfer is achieved. The flattened rake surfaces are particularly well suited for use with flat heating elements in the form of PTC resistors directly connected to the outer and inner parts, further improving heat transfer. Other clamping fixtures, in particular profiled fixtures are possible.

The wall thickness of the outer part may be greater in the region of the corners of the polygonal profile than in the region of the sides of the polygonal profile. As a result, a uniform heat dissipation in the region of the corners or clamping surfaces is achieved.

Preferably, the sides of the polygonal profile are concave, convex or straight. This results in various ways of mounting the heating elements, in particular different ways of initiating the assembly force.

The thickness of the sides of the polygon profile can change in the circumferential direction, in particular decrease towards the corners. Thus, the introduction of force during assembly is improved, which takes place in the central region of the pages, in particular at the apex of each page. The force is introduced linearly in the longitudinal axial direction. By maximizing the wall thickness or the thickness of the side in the middle region or at the apex, the force introduced there is safely transferred to the edge regions of the side in order to achieve maximum elastic deformation.

The inner part may have a number of corners of the polygon profile corresponding number of holding surfaces for the heating elements. In combination with the clamping surfaces results in a two-dimensional surface support for the heating elements, which ensures a secure mechanical support and a good thermal connection between the heating element and the body.

The inner part preferably has a polygonal profile with a plurality of corners, which are connected by sides, wherein the holding surfaces correspond to the corners of the polygonal profile.

The holding surfaces are supported in a preferred embodiment radially inwardly only by the sides of the polygonal profile. Due to the elasticity of the sides of the shape of the inner part and thus the location of the retaining surfaces is changeable. The inner part is flexible. By acting in a suitable direction on the sides of the polygonal mounting force, the retaining surfaces are radially inwardly movable to increase the mounting gap between the inner part and the outer part. In the case of convexly outwardly curved sides, the assembly or spreading force acts from the inside to the outside. The sides are pushed outward and pull the retaining surfaces radially inward. With concave inwardly curved sides, the mounting or spreading force acts from outside to inside. The sides are pressed inwards and pull the retaining surfaces radially inwards.

Alternatively, the retaining surfaces are supported by webs, wherein the webs each extend inward in the radial direction. Thereby, a relatively rigid shape of the inner part is achieved compared to the above-mentioned embodiment. The location of the support surfaces is relatively localized during installation. The webs also increase the effective for heat dissipation surfaces and improve the stability of the inner part.

In a particularly preferred embodiment, the heating elements PTC resistors, which are arranged in the receiving areas and connected directly to the outer part and the inner part, in particular thermally and electrically connected. The direct connection of the PTC resistors with the outer and inner part improves the heat transfer between the heating elements and the holding and cooling body. Alternatively, it is possible to arrange the heating elements in the form of known PTC cartridges in the receiving areas. For a protection class 2 application, a version with insulating foil and separate electrodes is conceivable.

In a further preferred embodiment, at least three heating elements are distributed on the circumference of the outer part, in particular distributed symmetrically. This number of heating elements leads to a static certain system, which is also self-centering. A larger number of heating elements is possible.

To increase the heat output, a plurality of layers of heating elements arranged in the radial direction may be provided, wherein at least one intermediate part is arranged between the outer part and the inner part. The receiving areas are formed on the one hand between the inner part and the intermediate part and on the other hand between the intermediate part and the outer part. The receiving areas formed between the inner and intermediate parts form a first inner layer of heating elements. The receiving areas formed between the intermediate part and the outer part receive a second, radially further outward layer of heating elements. By arranging further intermediate parts, the number of heating layers can be increased accordingly. Conceivable are 3, 4 or more than 4 heating layers, the intermediate parts of the individual heating layers are respectively constructed accordingly.

In the context of the invention, a heater is further disclosed and claimed, which has a cooling and holding body according to the invention. An axial end of the cooling and holding body is connected to a fan such that the cooling and holding body can be traversed in the longitudinal direction with air, which cools the heating elements and transports the heat to the desired location, for example in a cabinet. The arrangement of the inner and outer parts in combination with the fan ensures that the inner part is hotter compared to the outer part during operation and that the thermal expansion of the inner part additionally increases the clamping force during operation.

The cooling and holding body can be arranged in an insulated housing. This embodiment is particularly suitable for the case that the PTC resistors are connected directly to the outer part and / or the inner part.

In the context of the invention, a method for producing a cooling and holding body according to the invention is disclosed, in which the diameter of the outer part is increased for joining. To enlarge the diameter of the outer part is acted upon on the sides of the polygonal profile each with a radially inwardly or outwardly acting mounting force. Due to the installation force the polygon sides are elastich deformed. The individual components, ie the Inner part, the heating elements and the enlarged cross-section outer part are then assembled such that the heating elements are located in the respective receiving areas. Thereafter, the outer part is relieved, so that this shrinks on the heating elements and holds all the heating elements with the same contact pressure. In the context of the method according to the invention, the assembly of the outer part can be achieved either exclusively thermally by shrinking or exclusively mechanically by elastic deformation of the clamping element or by a combination of thermal and mechanical diameter enlargement.

Fig. 1

eine perspektivische Darstellung eines Kühl- und Haltekörpers nach einem erfindungsgemäßen Ausführungsbeispiel mit einer einzigen Umfangslage aus Heizelementen;

Fig. 2

eine Vorderansicht des kühl- und Haltekörpers gemäß Fig. 1;

Fig. 3

eine perspektivische Ansicht eines Kühl- und Haltekörpers nach einem weiteren erfindungemäßen Ausführungsbeispiel mit zwei Umfangslagen aus Heizelementen;

Fig. 4

eine Vorderansicht des Kühl- und Haltekörpers gemäß Fig. 3;

Fig. 5

eine perspektivische Ansicht des kühl- und Haltekörpers gemäß Fig. 3, dessen axiales Ende mit einem Lüfter verbunden ist und dessen innere Lage aus Heizelementen eine Fügehilfe aufweist; Fig. 6 eine perspektivische eines Kühl- und Haltekörpers nach einem weiteren Ausführungsbeispiel, bei dem die Heizelemente als PTC-Patronen ausgeführt sind;

Fig. 7

eine Vorderansicht des Kühl- und Haltekörpers gemäß Fig. 6;

Fig. 8

eine perspektivische Ansicht des Kühl- und Haltekörpers gemäß Fig. 6 mit einer Fügehilfe;

Fig. 9

ein Teilschnitt durch den Kühl- und Haltekörper gemäß Fig. 8;

Fig. 10

eine perspektivische Ansicht des Kühl- und Haltekörpers gemäß Fig. 6, der von einem isolierenden Gehäuse eines Heizgerätes umgeben ist;

Fig. 11

eine perspektivische Ansicht des Außenteils eines Kühl- und Haltekörpers, dessen Polygonseiten eine sich in Umfangsrichtung ändernde Wandstärke aufweisen;

Fig. 12

eine perspektivische Ansicht eines Innenteils mit einem konkaven Polygonprofil;

Fig. 13

eine perspektivische Ansicht eines Innenteils mit einem konvexen Polygonprofil.

The invention will be explained in more detail with reference to embodiments with reference to the accompanying schematic figures. In these show:

Fig. 1

a perspective view of a cooling and holding body according to an embodiment of the invention with a single circumferential layer of heating elements;

Fig. 2

a front view of the cooling and holding body according to Fig. 1 ;

Fig. 3

a perspective view of a cooling and holding body according to another erfindungemäßen embodiment with two circumferential layers of heating elements;

Fig. 4

a front view of the cooling and holding body according to Fig. 3 ;

Fig. 5

a perspective view of the cooling and holding body according to Fig. 3 whose axial end is connected to a fan and whose inner layer of heating elements has a joining aid; Fig. 6 a perspective of a cooling and holding body according to a further embodiment, in which the heating elements are designed as PTC cartridges;

Fig. 7

a front view of the cooling and holding body according to Fig. 6 ;

Fig. 8

a perspective view of the cooling and holding body according to Fig. 6 with a joining aid;

Fig. 9

a partial section through the cooling and holding body according to Fig. 8 ;

Fig. 10

a perspective view of the cooling and holding body according to Fig. 6 surrounded by an insulating housing of a heater;

Fig. 11

a perspective view of the outer part of a cooling and holding body whose Polygonseiten have a circumferentially changing wall thickness;

Fig. 12

a perspective view of an inner part with a concave polygonal profile;

Fig. 13

a perspective view of an inner part with a convex polygon profile.

In Fig. 1 is a perspective view of a cooling and holding body for an electric heating element 10 according to an embodiment of the invention shown in a heating device, such as in the Fig. 5 or 10 shown, can be installed. In the context of the invention, both the cooling and holding body with the heating elements per se, ie as an assembly, as well as the entire heater with such a cooling and holding body is disclosed and claimed.

The heating elements are known per se PTC heating elements, ie PTC thermistors with a positive temperature coefficient. The heating elements 10 generally have a flat cuboid shape. Other heating elements are possible.

As in the Fig. 1 and 3 shown, the cooling and holding body has an approximately cylindrical shape and extends in the axial direction, wherein the length of the cooling and holding body substantially corresponds to the length of the PTC resistors 10a and 10a of the heating elements in general. At the end faces of the cooling and holding body is slightly above the heating elements 10 before. The cooling and holding body according to Fig. 1 has a ring-like outer part 13 which surrounds an inner part 14 like a shell. The outer part 13 forms a shell element. The inner part 14 and the outer part 13 are arranged concentrically. The inner part 13 and the outer part 14 are two separate components, wherein the inner part 13 forms the core. The inner part 13 is not directly to the outer part 14, that is not materially bonded, but only connected by the heating elements 10 arranged therebetween. The core or the inner part 13 is arranged freely in the outer part 14.

Between the inner part 14 and the outer part 13, the Heizelementaufnahme 11 is formed. For this purpose, a gap, in particular an annular gap is formed between the inner part 13 and the outer part 14, whose shape and / or width changes in the circumferential direction. In the region of the gap between the inner part 13 and the outer part 14 a plurality of receiving areas 15 are distributed over the circumference provided, which together form a Heizelementeaufnahme 11. In the region of the Heizelementeaufnahme 11 and the respective receiving areas 15 of the gap is perpendicular to the radius of the cooling and holding body. Between the receiving areas 15 follows the gap of the contour of the clamping portions 16 and is radially outwardly bounded by these. The receiving areas 15 are therefore offset geometrically from the clamping portions 16. But this is not absolutely necessary.

In the receiving areas 15, the heating elements 10 are arranged. The heating elements 10 are thus located between the inner part 13 and the outer part 14 and are fixed there in a press fit.

The receiving areas 15 are arranged eccentrically on the circumference of the cooling and holding body and spaced in the circumferential direction. In the example according to Fig. 1 the angle between two adjacent receiving areas 15 is 120 °. As a result, the heating elements 10 are in the ideal air flow.

For clamping the heating elements 10, the outer part 13 clamping surfaces 16 and the inner part 14 corresponding retaining surfaces 17, which lie opposite the clamping surfaces 16. The formed on the inner circumference of the receiving part 13 clamping surfaces 16 and formed on the outer periphery of the inner part 14 retaining surfaces 17 form outer and inner contact surfaces 12 of the respective receiving areas 15. Die Heizelemente 10 abut Contact surfaces 12 on. The clamping and holding surfaces 16, 17 limit the gap or the respective receiving areas 15 in the radial direction. In the circumferential direction, the receiving areas 15 are open. In the embodiment according to Fig. 1 are the clamping and holding surfaces 16, 17 flattened or straight. This shape of the clamping and holding surfaces 16, 17 is particularly well suited for direct connection to a flat PTC resistor 10a, as in Fig. 1 shown. Other shapes are possible.

The circumferentially immediately adjacent clamping surfaces 16 are connected by a convexly curved clamping portion 18. The clamping portion 18 may also be concavely curved or straight. In the assembled state, the clamping portion 18 is elastically deformed and acts on the respective clamping surfaces 16 associated heating elements 10 with a contact force acting like a spring in the direction of the respective associated holding surface 17.

As in Fig. 1 to recognize, the outer part 13 has a polygonal profile, wherein the clamping surfaces 16 are arranged in the region of the corners 19 a of the polygonal profile. The clamping portions 18 form the sides 19b of the polygonal profile. In the embodiment according to Fig. 3 three sides are provided, resulting in a statically determined structure. In the embodiment with a statically determined arrangement of the surfaces of the contact pressure is applied concentrically to the heating elements 10. The three-sided polygonal profile has the further advantage that the arrangement is self-centering, whereby the assembly is simplified. A different number of polygon corners is possible.

The polygonal profile of the outer part 13 has the further advantage that the sides 19b of the polygonal profile or the clamping portions 18 can be acted upon for mounting with a radially inwardly acting mounting force, as in Fig. 2 represented by the radially inwardly directed arrows M. The mounting force can be applied for example by appropriately arranged mounting punch (not shown). By the mounting force, the clamping portions 18 are slightly widened or elongated, so that the clamping surfaces 16 move radially outward, as shown by the smaller radially outwardly directed arrows L in Fig. 2 clarified. A slight change in position of the clamping surfaces 16 is sufficient to allow the assembly of the cooling and holding body. After mounting the heating elements 10 between the inner part 14 and the outer part 13th the assembly force is released and the clamping action of the outer part 13, justified by the elastic material deformation occurs.

In the mounted state, the heating elements 10 are therefore fixed in a press fit between the inner part 14 and the outer part 13, specifically between the respective holding surface 17 of the inner part 14 and the associated clamping surface 16 of the outer part 13. In this case, the excess between the respective heating element 10 and the outer part 13 is set so that the polygon sides or clamping sections 18 deform elastically. The deformation takes place in the area of Hooke's straight line, ie below the elastic limit. This applies to all receiving areas 15. The expert will make the adjustment of a suitable oversize depending on the respective material properties.

Alternatively or additionally, the mounting of the cooling and holding body can be thermally assisted in so far as the outer part 13 is heated. After mounting the heating elements 10 by thermal expansion, the outer part 13 is cooled and shrinks on this. The mechanical and thermal expansion of the outer part 13 can be combined. The mechanical expansion can be varied depending on the shape of the clamping portions 18. For example. can be expanded with convex clamping portions 18 (not shown), the outer part 13 with radially outwardly acting mounting forces.

For a uniform heat dissipation, the wall thickness of the outer part 13 in the region of the clamping surfaces 17 is increased. Specifically, the wall thickness in the region of the clamping surfaces 17 is greater than the wall thickness in the region of the clamping sections 18. The heat dissipation can be increased by additional cooling ribs on the outer circumference of the outer part 13 (not shown).

The inner part 14, specifically the holding surfaces 17 on which the heating elements 10 are arranged, has the function of an abutment. The inner part 14 is therefore designed so that it can absorb the introduced from the outer part 13 holding forces. The outer part 13 is therefore more elastically deformable than the inner part 14. The rigid shape of the inner part 14 is achieved by a plurality of webs 20 extending in the radial direction. At the radially outer end of the webs 20 each have a holding surface 17 is arranged. In the area of the holding surface 17, the webs 20 are T-shaped, wherein the top of the T-profile the Holding surface 17 forms. The webs 20 each have a foot 21, according to the embodiment Fig. 2 is connected to an inner cylinder 22. The inner cylinder 22 is arranged concentrically with respect to the cooling and holding body. It is a hollow inner cylinder 22. The inner cylinder may have a different cross-section than in Fig. 2 shown.

The inner part 14 has a polygonal profile which essentially corresponds in its shape to the polygonal profile of the outer part 13, such as, for example, in FIG Fig. 1 shown. The sides 19b 'of the polygonal profile of the inner part 14 connect the retaining surfaces 17 provided in the region of the corners 19a' of the polygonal profile. As a result, the stability of the inner part 14 is improved.

Between the webs 20 hollow chambers are formed to effectively and quickly transport the heated air away from the heating element. This can be further improved by a machined surface (vortex effects).

The invention is not on the in the Fig. 1, 2 In general, the polygon sides 19b or clamping portions 18 are curved between the corners 19a, convex convex convex toward the outside or curved concavely inwards. The polygon sides 19b or clamping sections 18 may be straight. The polygon corners 19a are to be understood as the regions in which adjacent polygon sides 19b are connected. The polygon corners 19a extend transversely to the longitudinal axis of the cooling and holding body and form abutment or contact surfaces 12 for the heating elements 10. The polygon corners 19a are flattened, in particular flattened on the inside.

The number of heating elements 10 may vary. It is possible to use more than three heating elements 10, for example in conjunction with a 4, 5 or polygonal polygonal profile of the outer part 13. The receiving areas 10 of a polygonal polygonal profile are arranged distributed uniformly on the circumference. In the embodiment according to Fig. 1 with three heating elements 10, the receiving areas 15 and the heating elements 10 are distributed over an angle of 120 ° on the circumference.

As the material, for example, aluminum or aluminum alloys can be used for both the outer part 13 and the inner part 14. Other materials are possible. The choice of material takes into account that after assembly elastic deformation of the clamping portions 18 occurs such that they exert a spring force in the direction of the support surfaces 17 on the clamping surfaces 16 on the heating element 10. The material alloys of inner part 14 and outer part 13 may be different, so that different thermal expansions take place at the same temperature. The thermal expansion coefficient of the inner part 14 should be greater than the thermal expansion coefficient of the outer part 13.

In the 3 and 4 is a further development of the embodiment according to Fig. 1, 2 shown, in which a plurality of heating element layers are provided. Specifically, in the embodiment according to the Fig. 3, 4 provided two Heizelementlagen. Incidentally, the embodiments agree according to the Fig. 1, 2 respectively. Fig. 3, 4 match. In this respect, in connection with the embodiment according to 3 and 4 to the above remarks to the Fig. 1, 2 Referenced. The embodiment according to Fig. 3 differs from the embodiment according to Fig. 1 by the intermediate part 23, which is arranged between the inner part 14 and the outer part 13. The shape of the intermediate part 23 essentially corresponds to the shape of the outer part 13. Accordingly, the intermediate part 23 has a polygonal profile, wherein in the region of the corners of the polygonal profile the wall is flattened both on the outer and on the inner diameter. Moreover, the wall thickness in the area of the polygon corners is greater than in the area of the polygon sides. The transition from polygon side or chord and polygon corner has a radius such that the notch effect in the transition region is minimized or reduced. This also applies to the embodiment according to Fig. 1 ,

In the assembled state, the receiving area 15 for the heating elements 10 is on the one hand between the inner part 14 and the intermediate part 23. These receiving areas 15 form the radially inwardly arranged receiving areas of the Heizelementaufnahme 11. The formed between the intermediate part 23 and the outer part 13 receiving areas 15 form the radial outer receiving areas. As in Fig. 3 shown, the inner and outer receiving area are each in the radial direction one above the other.

Between the receiving areas 15, the clamping portions 18 are provided, wherein in the assembled state, the clamping portions 18 of the intermediate part 23 and the clamping portions 18 of the outer part 13 are arranged one above the other. The position of the various sections or areas of the intermediate part 23 and the outer part 13 is thus arranged accordingly.

The inner part 14 of the embodiment according to Fig. 3 substantially corresponds to the inner part 14 of the embodiment according to Fig. 1 , at least as far as the arrangement of the radial webs 20 is concerned.

The two-layer arrangement according to Fig. 3 can be extended to a three-layer, four-layer or generally multi-layer arrangement, wherein the number of intermediate parts 23 is adjusted accordingly. The shape of the intermediate parts 23 corresponds in each case to the shape and position of the outer part 13.

For mounting the heating elements, joining means 26 can be used which hold the heating elements 10 in the correct position during assembly. As in Fig. 5 shown, the joining means 26 are formed as brackets which engage around the webs 20 in the axial direction. As a result, the clamps are fixed on the inner circumference of the inner part 14 at least in the circumferential direction.

In the embodiments according to Fig. 1, 2 or 3, 4, the PTC resistors 10a are connected directly to the inner part 14 and the outer part 13, respectively. Deviating from this is in Fig. 6 illustrated that with the cooling and holding body PTC cartridges 10b can be used, which are arranged at corresponding positions in the region of the corners 19 of the polygonal profile. The shape of the holding surfaces 17 and the clamping surfaces 16 is adapted to the outer contour of the approximately cylindrical PTC cartridges 10 b, as well as in Fig. 7 shown. The holding surfaces 17 and the clamping surfaces 16 are formed as half shells. The half-shells are profiled and engage in a corresponding counter-profile of the PTC cartridges, much like a tongue and groove system.

In the Fig. 8 . 9 is shown that the joining aid 26 different from the embodiment according to Fig. 5 can attack on the outer part 13.

In Fig. 10 the cooling and holding body is shown in the installed state, wherein the axial end 24 of the cooling and holding body with a fan 25th connected is. The cooling and holding body is located in a housing 27, which may be insulated, for example when the current-conducting PTC resistors are connected directly to the outer part 13 and the inner part 14, as in the embodiment according to Fig. 1 shown. The end face of the housing 27 may be closed by a protective grid, not shown.

A modification of the outer part 13 is in FIG. 11 shown, in which the wall thickness or the thickness of the polygon sides 19b changes in the circumferential direction of the outer part 13. Specifically, the wall thickness decreases towards the edge regions of the polygon sides 19b, ie towards the corners 19a. The polygon sides 19b taper toward the corners 19a. The maximum wall thickness is in the middle region, specifically in the region of the apex of the polygon side 19b. The vertex is indicated by the dashed line S, which intersects the center of the outer part 13 and bisects the polygon side 19b. As in FIG. 11 As can be seen, the change in the wall thickness is continuous. The radius of the polygon side 19b between the vertex and the corner 19a is denoted by R. By increasing the wall thickness in the region of the apex of the polygon side 19b, a stiffening of the polygon side 19b is achieved, which improves the transmission of force into the edge regions. Other stiffeners of the polygon side 19b are possible, for example stiffening ribs which prevent local deformation of the polygon side 19b in the region of the vertex or at the point of application of the mounting force or reduce.

It is understood that the increase in the wall thickness in the region of the apex of the polygon side 19b extends along the entire axial length of the outer part region.

In the Figures 12 and 13 Embodiments are shown in which the inner part 14, so the inner Heizelementkern is designed to be movable. The outer circumference of the Heizelementekerns or the inner part 14 can be reduced by a suitable application of force. This ensures that the gap between the inner part 14 according to FIG. 12 . 13 and the outer part 13 is increased according to one of the aforementioned embodiments. Due to the larger gap tolerances of the introduced into the receiving area 15 heating element even better balanced. Accordingly, the below-described features of the inner parts according to FIG. 12 . 13 in the Relates to the context of all the above embodiments disclosed and claimed.

The increased flexibility of the inner part 14 according to the Figures 12 . 13 is achieved in that the retaining surfaces 17 are supported radially inwardly only by the sides 19 b 'of the polygonal profile. In other words, the differences from the embodiment according to FIG. 1 no webs provided which support the retaining surfaces 17 radially inwardly and thus stiffen the inner part 14. The inner part 14 according to the Figures 12 . 13 is designed without installation, ie, no support elements for the retaining surfaces 17 are provided in the interior of the inner part 14. The retaining surfaces 17 can thus move radially inward or radially outward depending on the material properties and the mounting force to be applied.

This is achieved in that the inner part 14 according to FIG. 12 . 13 is designed as a polygonal profile, wherein the examples according to Figures 12 . 13 differ by the shape of the polygon sides 19b '. In the example according to FIG. 12 are the polygon sides 19b 'concave, that is curved inwardly. When an inwardly acting pressing force or mounting force is applied to the polygon side 19b ', the holding surfaces 17 are pulled radially inwardly and the inner part 14 is reduced in size. In the embodiment according to FIG. 13 the polygon sides 19b 'are convex. The polygon sides 19b 'curve outward. If in the inner part 14 according to FIG. 13 an expanding force or a mounting force is applied, which acts on the polygon sides 19b 'from the inside to the outside, the flat sides or the holding surfaces 17 are also drawn radially inwardly, whereby the mounting gap increases.

It is also conceivable to form the polygon sides 19b 'straight.

In summary, the outer part 13 forms a mechanical tensioning element in the form of a polygonal profile, wherein the contact pressure force is achieved by elastic deformation of the outer part 13. The deformation is thus effected in the stress-strain diagram in the region of Hooke's straight line. This has the advantage that can be dispensed with additional spring elements. The clamping effect is reinforced by the geometry of the outer part 13, which has between the clamping surfaces 13 clamping portions 18, in particular convex or concave curved or straight clamping portions 18. The clamping sections 18 bridge the distance between the clamping surfaces 16 and connect them. The same principle can be realized by the inner part, which is also designed as a polygonal profile.

Due to the overall low mass of the outer part 13 connected to the strong clamping pressure exerted by the outer part 13 on the heating elements 10, an optimal heat extraction is effected. This is supported by the fact that the heating elements are arranged on the outer circumference of the cooling and holding body. For a direct voltage supply can be formed in the material of the cooling and holding body, a channel to crimp a phase or a neutral directly.

LIST OF REFERENCE NUMBERS

10

heating element

11

heaters recording

12

contact surfaces

13

outer part

14

inner part

15

receiving areas

16

clamping surfaces

17

holding surfaces

18

clamping sections

19

Corners of the polygonal profile 19a, 19a '/ sides of the polygonal profile 19b, 19b'

20

Stege

21

foot

22

inner cylinder

23

intermediate part

24

Axial end

25

Fan

26

joining means

27

casing

R

radius

S

Vertex line

Claims (12)

1. Heat sink and holding body for heating elements (10), in particular PTC heating elements, having a heating-element receptacle (11) in which the heating elements (10) are clamped, wherein
   the heating-element receptacle (11) has a plurality of receptacle regions (15) which are located in a distributed manner in the circumferential direction and in which at least one heating element (10) is in each case located, and wherein

   - the receptacle regions (15) are formed between an outer part (13) and an inner part (14), which is located in the outer part (13), and

   - at least the outer part (13) has a polygonal profile with a plurality of corners (19a) which are connected by sides (19b), wherein the receptacle regions (15) are located in the corners (19a) of the polygonal profile,

   characterized in that
   the sides (19b) of the polygonal profile are elastically deformed for generating a clamping force which acts on the respective heating elements (10).
2. Heat sink and holding body according to Claim 1, characterized in that
   the corners (19a) of the polygonal profile form clamping faces (16) which are adapted, in particular flattened, to suit the shape of the heating elements (10).
3. Heat sink and holding body according to Claim 1 or 2,
   characterized in that
   the wall thickness of the outer part (13), in the region of the corners (19a) of the polygonal profile, is greater than in the region of the sides (19b) of the polygonal profile.
4. Heat sink and holding body according to one of the preceding claims,
   characterized in that
   the sides (19b) of the polygonal profile are configured to be concave, convex or straight.
5. Heat sink and holding body according to one of the preceding claims,
   characterized in that
   the thickness of the sides (19b) of the polygonal profile varies in the circumferential direction, in particular decreases towards the corners (19a).
6. Heat sink and holding body according to one of the preceding claims,
   characterized in that
   the inner part (14) has a number of holding faces (17) for the heating elements (10) which corresponds to the number of corners (19b) of the polygonal profile.
7. Heat sink and holding body according to Claim 6,
   characterized in that
   the inner part (14) has a polygonal profile with a plurality of corners (19a') which are connected by sides (19b'), wherein the holding faces (17) correspond to the corners (19a').
8. Heat sink and holding body according to Claim 6,
   characterized in that
   the holding faces (17) are supported radially towards the inside only by the sides (19b') of the polygonal profile, or the holding faces (17) are supported by webs (20), wherein the webs (20) extend in each case in the radial direction towards the inside.
9. Heat sink and holding body according to one of the preceding claims,
   characterized in that
   at least three heating elements (10) are located in a distributed manner on the circumference.
10. Heat sink and holding body according to one of the preceding claims,
    characterized in that
    a plurality of layers which are located in the radial direction and consist of heating elements (10) are provided, wherein at least one intermediate part (23) is located between the outer part (13) and the inner part (14), wherein the receptacle regions (15) of the inner layer are configured between the inner part (14) and the intermediate part (23), and the receptacle regions (15) of the outer layer are configured between the intermediate part (23) and the outer part (13).
11. Heating apparatus having a heat sink and holding body according to one of the preceding claims, wherein an axial end (24) of the holder is connected to a blower (25) in such a manner that air can flow through the heat sink and holding body in the longitudinal direction.
12. Method for manufacturing a heat sink and holding body according to Claim 1, in which the diameter of the outer part (13) is enlarged for joining, wherein

    - the outer part (13), on the sides (19b) of the polygonal profile, is in each case impinged and elastically deformed by a fitting force which acts radially towards the inside or radially towards the outside,

    - then the inner part (14), the heating elements (10) and the outer part (13) are assembled in such a manner that, after assembly, the heating elements (10) are situated in the receptacle regions (15), and

    - then the outer part (13) is de-stressed.

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