Abstract
An electric heating device includes at least two hollow profile elements which form a fluid channel for a fluid to be heated and, opposite the fluid channel, a heating chamber which is bounded by opposite contact surfaces against which at least one PTC element abuts in a heat-conducting manner. A scalable and easier to assemble electric heating device is achieved by connecting the hollow profile elements to one another by complementary form-fit segments.
Claims
1. An electric heating device, comprising: at least two hollow profile elements which form a fluid channel for a fluid to be heated and which form aa heating chamber which is located opposite the fluid channel and which is bounded by opposite contact surfaces; at least one PTC element which abuts against at least one of the contact surfaces in a heat-conducting manner; and complementary form-fit segments which connect the hollow profile elements to one another.
2. The electric heating device according to claim 1, wherein the fluid channel or the heating chamber is laterally delimited by the form-fit segments.
3. The electric heating device according to claim 1, wherein the form-fit segments form a tongue and groove connection, and wherein t the tongue is positively locked in the groove.
4. The electric heating device according to claim 3, wherein the form-fit segments comprise a saw tooth profile which allows a positive locking of the hollow profile elements with different distance of the opposing contact surfaces.
5. The electric heating device according to claim 3, wherein the form-fit segments are configured such that the hollow profile elements are movably and captively connected to each other orthogonally to the contact surface.
6. The electric heating device according to claim 1, wherein each hollow profile element forms at least two fluid channels separated by a partition wall, and wherein each of the hollow profile elements is provided on an end face thereof with a cover through which fluid flow from one fluid channel of the hollow profile element is deflected into the other fluid channel of the hollow profile element, and wherein at least one of the hollow profile elements is provided o with a connection housing which connects one of the fluid channels to an inlet opening for the fluid to be heated and the other of the fluid channels to an outlet opening for the fluid to be heated.
7. The electric heating device according to claim 6, wherein the connection housing comprises electrical conduction paths connecting strip conductors, which are electrically conductively connected to the PTC element, to an interface for power current.
8. The electric heating device according to claim 7, wherein the electrical conduction paths connect the strip conductors to a control housing which accommodates therein a control unit for controlling the power current and which abuts an outer surface of at least one of the hollow profile elements that extends perpendicularly to the contact surface.
9. The electric heating device according to claim 8, wherein the connection housing and the control housing are formed in a common component which is connected in a fluid-tight manner at an end face to the hollow profile elements.
10. The electric heating device according to claim 1, wherein the hollow profile elements of the electric heating device are encompassed by a clamp.
11. The electric heating device according to claim 1, wherein the hollow profile elements are arranged in a stack, and wherein a functional module is connected to an outside surface of the stack of hollow profile elements via at least one of the form-fit segments that is exposed on the outside surface of the stack.
12. An electric heating device comprising: a stack of hollow profile elements including at least two hollow profile elements which form a fluid channel for a fluid to be heated; complementary form-fit segments which connect the at least two hollow profile elements to one another; a heating channel that is located opposite the fluid channel and that is bounded by opposite contact surfaces; at least one PTC element which abuts against at least one of the contact surfaces in a heat-conducting manner; and a functional module that is connected to an outside surface of the stack of hollow profile elements via at least one of the form-fit segments that is exposed on the outside surface of the stack.
13. The electric heating device according to claim 12, wherein each hollow profile element forms at least two fluid channels separated by a partition wall, wherein the hollow profile elements are provided on one a first face with a cover through which the flow from one fluid channel of the hollow profile element is deflected into the other fluid channel of the hollow profile element, and wherein the hollow profile element is provided on a second end face that is opposite the first end face with a connection housing which connects one of the fluid channels to an inlet opening for the fluid to be heated and the other of the fluid channels to an outlet opening for the fluid to be heated.
14. The electric heating device according to claim 13, wherein the connection housing comprises electrical conduction paths connecting strip conductors, which are electrically conductively connected to the PTC element, to an interface for power current.
15. The electric heating device according to claim 14, wherein the electrical conduction paths connect the strip conductors to a control housing which accommodates therein a control unit for controlling the power current and abuts an outer surface of at least one of the hollow profile elements that extend perpendicularly to the contact surface.
16. The electric heating device according to claim 15, wherein the connection housing and the control housing are formed in a common component which is connected in a fluid-tight manner at the second end face to the hollow profile elements.
17. The electric heating device according to claim 12, wherein the hollow profile elements of the electric heating device are encompassed by a claim.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] Further advantages and details of the present invention will be apparent from the following description of an embodiment in conjunction with the drawing. Therein:
[0026] FIG. 1 shows a perspective front view of an embodiment of a hollow profile element;
[0027] FIG. 2 shows a perspective front view of joined form-fit segments of two interconnected hollow profile elements;
[0028] FIG. 3 shows a perspective side view of an embodiment of an electric heating device;
[0029] FIG. 4 shows a perspective sectional view of an embodiment different from that shown in FIG. 3;
[0030] FIGS. 5A-5D show perspective views of the end faces of a stack with different variants of clamps for bracing the stack;
[0031] FIG. 6 shows a perspective front view of another embodiment of an electric heating device according to the present invention;
[0032] FIG. 7 shows a variation on the embodiment shown in FIG. 6;
[0033] FIG. 8 shows the embodiment according to FIG. 6 with an embodiment of a function module;
[0034] FIG. 9 shows a stack of hollow profile elements approximately as shown in FIG. 7, and
[0035] FIG. 10 shows a perspective front view of joined form-fit segments of two hollow profile elements connected by a saw tooth profile.
DETAILED DESCRIPTION
[0036] FIG. 1 shows a perspective front view of a hollow profile element 2 in the form of an extruded profile with a substantially rectangular base area. A partition wall 6 protrudes from opposite contact surfaces 4, dividing a central cavity of the hollow profile element 2 into two fluid channels 8. The contact surfaces 4 are projected at the edges by tongues 10 at the top and by grooves 12 at the bottom, which form form-fit segments in the sense of the present invention. These form-fit segments 10, 12 extend the hollow profile element 2 in the height direction.
[0037] FIG. 2 illustrates the joining of two adjacent hollow profile elements 2.1 and 2.2. A PTC heating assembly 14 with two insulating layers 16 in the form of separate ceramic plates applied against the main side surface 4 is located between opposing contact surfaces 4 of the respective hollow profile elements 2.1, 2.2. These insulating layers are provided between the contact surfaces 4 and the strip conductors 18 and support the same in an electrically insulating manner with respect to the contact surface 4. The strip conductors 18 accommodate between them a PTC element 20 and a position frame 22 which spaces apart a plurality of PTC elements 20 one behind the other in a plane in the longitudinal direction L of the hollow profile element.
[0038] As FIG. 2 illustrates, the joined form-fit segments 10, 12 project vertically beyond a heating chamber 24 formed between the main side surfaces 4. In this way, the heating chamber 24 is electromagnetically shielded from the outside. In this context, it is irrelevant whether the groove 12 and the tongue 10 each project beyond the contact surface 4 associated therewith. It is only important that the heating chamber 24 is also laterally enclosed by the metallic material of the hollow profile elements 2.1, 2.2. The hollow profile elements 2 are made of aluminum.
[0039] FIG. 3 shows a stack, characterized by reference sign 26, of several hollow profile elements 2 connected to each other via the form-fit segments 10, 12, each of which accommodates a PTC heating assembly 14 between them. At an end face of the stack 26, a connection housing 28 is shown, which is applied sealingly against the respective fluid channels 8 and forms inlet and outlet openings, not shown, for the introduction and discharge of a fluid to be heated from the electric heating device. This connection housing 28 is sealed from the stack 26 via a molded seal. The seal also covers the respective heating chambers 24 so that the PTC heating assemblies 14 are separated from the fluid to be conducted.
[0040] FIG. 3 schematically shows a control housing segment 30 of the connection housing 28 for accommodating a control device, not shown, for controlling the power current. This is electrically connected to the strip conductors 18 of the respective PTC heating assemblies 14. For this purpose, the strip conductors 18 formed from sheet metal strips are extended over the stack 26. The connection housing 28 can form plug-in element receptacles which are plugged into the terminal lugs of the strip conductors 18 when the connection housing 28 is slid open.
[0041] The connection housing 28 has flange surfaces 32 laterally enclosing the stack 26, which brace the stacking 26 so that the respective PTC heating assemblies 14 rest with a certain pretension against the associated contact surfaces 4. In any case, the flange surfaces 32 are designed to interact with the contour of the tongue 10 and groove 12 in such a way that the connection housing 28 is positively fixed relative to the stack 26.
[0042] The fixing of the hollow profile elements 2 against each other via the respective form-fit segments 10, 12 can be taken from FIG. 2. Therein, reference sign 34 illustrates a widened head as part of the tongue 10 which is engaged in the groove 12. Opposite wall segments 36, which laterally delimit the groove 12, are inclined towards each other. Thus, the mouth of the groove 12 is narrower than an area of the groove 12 near its groove bottom 38. As a result, the adjacent hollow profile elements 2 are locked and captive to each other after the tongue 10 is inserted into the groove 12.
[0043] In FIG. 2, there is still sufficient distance between the head 34 and said groove bottom 38. In this context, the PTC heating assembly 14 is already abutting against the opposing contact surfaces 4. The corresponding free space between the head 34 and the groove bottom 38 can accommodate a further relative movement of the hollow profile elements 2 when these are braced against each other in order to apply the layers of the PTC heating assembly 14 against each other under pretension.
[0044] FIG. 4 illustrates a cross-sectioned embodiment with several hollow profile elements 2, each of which accommodates PTC heating assemblies 14 between them, as described with reference to the preceding Figures. On the left side in FIG. 4, a connection housing 28 is provided with inlet and outlet openings 39, which are formed by nozzles projecting beyond the actual connection housing 28. Internally, this connection housing 28 forms deflection chambers 41 which communicate with adjacent fluid channels 8 to transfer the flowing medium from one fluid channel 8 to the adjacent fluid channel 8. Similarly, a cover characterized by reference sign 43 is configured to form deflection chambers 41 for the flowing fluid on the side opposite the connection housing 28.
[0045] Various possibilities for bracing the hollow profile elements 2 are shown in FIGS. 5A-D.
[0046] According to the variant according to FIG. 5A, L-shaped bent-over clamps 40 are pushed over the stack 26. The ends of the clamps, which are characterized by reference sign 42, are bent at right angles to a web 44 of the clamp 40 and curved convexly in the direction of the stack 26. Thus, the raised form-fit segments 10, 12 are positively encompassed by the clamp 40. The clamp 40 is dimensioned such that a pretensioning force is effected in this case, which is guided in each case over the contact surfaces 4 and through the PTC heating assemblies 14. The form-fit segments 10, 12 do not transmit the contact pressure force. These form-fit segments 10, 12 merely serve to fix the hollow profile elements 2 in a direction opposite to the pretensioning force.
[0047] In the variant shown in FIG. 5B, the webs 44 are bent over in a W-shape in their center, thereby forming a spring segment 46 through which the clamp 40 is able to store an elastic pretensioning force in an improved manner.
[0048] According to the variant shown in FIG. 5C, the spring segments 46 are formed in a trapezoidal shape. The spring segment 46 can be formed after the clamps 40 have been placed around the stack 26 by a forming tool forming the spring segments 46 by cold forming and thereby setting the desired clamping force in the clamp 40. In this way, during the manufacture of the heating device, adding tolerances due to different thicknesses of the individual PTC elements can be compensated.
[0049] This effect is also shown in the variant according to FIG. 5D. This shows a clamp 40 circumferentially surrounding the stack 26, consisting of a first clamp component 48 and a second clamp component 50, each of which is bent around in a U-shape. The clamp components 48, 50 are connected to each other by a positive connection 52 comprising a plurality of cooperating teeth so that the two clamp components 48, 50 can be pushed together to the extent desired to brace the stack 26 and secured against each other. On the outer exposed contact surfaces 4, a head portion 54 of the respective clamp components 48, 50, which is convexly curved in the direction of the stack 26, abuts under elastic pretension.
[0050] In the embodiment shown in FIG. 6, the electric heating device has a first hollow profile element 2a and a second hollow profile element 2b, which are connected to each other by a tongue 10 and a groove correspondingly provided thereto, with the PTC heating assembly 14 being provided in the heating chamber 24. Ribs 58 project from main walls 56a, b, which enclose the fluid channel 8 between them, are integrally formed on the hollow profile elements 2 and are intended to improve heat transfer between the PTC heating assembly 12 and the fluid in the fluid channels 8.
[0051] In the embodiment according to FIGS. 6 to 9, the PTC heating assembly 14 is held in the respective hollow profile element 2a by clamping between the main side walls 56a, b with good thermal conductivity. The main wall characterized by reference sign 56a has a crowned shape and is correspondingly stiffened at the center. The contact surface 4 is formed with a step 60 projecting in the direction of the PTC heating assembly 14. Between this step 60 and a side edge of the hollow section, edge-side deformation areas 62 of reduced cross-section are formed. A deformation tool can act there. The deformation force applied in this process acts outside the contact surface of the hollow profile element 2a to the PTC heating assembly 14. During this deformation, the hollow profile element 2a can be enclosed at the edge so that the deformation tool only acts locally on the deformation area 62, but the basic shape of the hollow profile element 2a otherwise remains unchanged. Impeding the compensating movement of the hollow profile element 2a improves the abutment of the PTC heating assembly 14 under pretension against the contact surfaces 4.
[0052] FIG. 7 shows a hollow profile element 2 that can be integrated into a stack of multiple hollow profile elements. This embodiment has a heating chamber 24 as described above, in which the PTC heating assembly 14 is accommodated in the manner described above. This hollow profile element 2 has form-fit segments on opposite sides in the form of a groove 12 (top) and in the form of a tongue 10 (bottom), respectively.
[0053] FIG. 9 illustrates a stack 26 consisting of such hollow profile elements 2. This stack 26 can be surrounded by at least one clamp segment as previously described with reference to FIGS. 5A-D. For sealing the individual fluid channels 8, which are each bounded by two hollow profile elements 2, a permanently elastic sealant or a setting adhesive can be filled into the groove 12. Additionally or alternatively, such a sealant can also be applied against the wall segments at the ends.
[0054] FIG. 8 shows a variant of the embodiment according to FIG. 6. Reference sign 64 characterizes a functional module comprising an extruded profile 66. This extruded profile has form-fit segments in the form of tongues 10 provided at the edges, which engage in the grooves 12 of the hollow profile element 2a and thereby seal off one of the fluid channels 8. The extruded profile 66 has two fastening grooves 68 open towards the main side, into which self-tapping screws 70 are screwed, which penetrate an angle plate 72, via which the electric heating device can be mounted, for example, on the chassis of a vehicle.
[0055] FIG. 10 illustrates form-fit segments with a corresponding saw tooth profile 74. In this context, saw teeth are provided on both sides of the head 34 and the inner surfaces of the wall segments 36. This saw tooth profile acts like a ratchet. The hollow profile elements 2 can be positively fixed at different distances relative to each other. Tolerance compensation is also provided by insulating layers 16 with compressible properties, the thickness of which can be varied while storing elastic pretension. The insulating layers 16 are provided at a distance from the lateral boundary of the heating chamber 24. The insulating layers 16 are accordingly less wide than the heating chamber 24. The insulating layers 16 can accordingly be stretched in the width direction.
