PTC Heating Assembly and Electric Heating Device Comprising the Same

Abstract

APTC heating assembly includes contact elements and a cuboid ceramic component on which a metallization is applied. The ceramic component comprises mutually opposing main side surfaces for heat dissipation which are larger by at least a factor of five than each of the end faces extending between the main side surfaces. The contact elements are electrically conductively connected to the metallization for introducing the power current into the ceramic component. The metallization is formed only on the main side surfaces and is in the form of elongated metallization strips. The metallization strips extend along mutually opposite edges of the cuboid ceramic component, are each assigned to one polarity, are separated by a single end face, and are connected to a power source via a common contact element.

Claims

1. A PTC heating assembly comprising: a cuboid ceramic component on which a metallization is applied, wherein the ceramic component comprises mutually opposing main side surfaces for heat dissipation and first and second end faces extending between the main side surfaces, wherein the main side surfaces are larger by at least a factor of five than each of the end faces; contact elements that are electrically conductively connected to the metallization for introducing a power current into the ceramic component via the metallization, wherein the metallization is formed only on the main side surfaces and is in the form of elongated metallization strips extending along mutually opposing edges of the cuboid ceramic component, and wherein two elongated metallization strips are provided which are each assigned to a common polarity, which are separated by a single end face of the ceramic component, and which are configured to be connected to a power source via a common contact element.

2. The PTC heating assembly according to claim 1, wherein a contact element forms two contact surfaces which abut only against the main side surfaces and of which one contact surface contacts a first metallization strip and the other contact surface contacts a second metallization strip which is separated from the first metallization strip only by an end face.

3. The PTC heating assembly according to claim 1, wherein a contact element is formed as a claw having two substantially parallel extending legs abutting against the opposite main side surfaces and contacting the metallization strips, and a wherein the claw further comprises a web that is provided between the legs and that extends substantially parallel to the end face.

4. The PTC heating assembly according to claim 3, wherein the claw is connected to the ceramic component via a clamp connection.

5. An electric heating device comprising: at least one heater housing having a circulation chamber and a connection chamber separated by a partition wall; a PTC heating assembly arranged in the circulation chamber; wherein the PTC heater assembly includes at least one ceramic unit on which a metallization is applied, contact elements, a housing which joins the ceramic component and the contact elements as a structural unit, contact lugs which project through the partition wall and into the connection chamber and which are configured to be connected to a power source, wherein the ceramic component comprises mutually opposing main side surfaces for heat dissipation and first and second end faces extending between the main side surfaces, wherein the main side surfaces are larger by at least a factor of five than each of the end faces, wherein the contact elements are electrically conductively connected to the metallization for introducing a power current into the ceramic component via the metallization, wherein the metallization is formed only on the main side surfaces and is in the form of elongated metallization strips extending along mutually opposing edges of the cuboid ceramic component, and wherein two elongated metallization strips are provided which are each assigned to a common polarity, which are separated by a single end face of the ceramic component, and which are configured to be connected to a power source via a common contact element.

6. The Electric heating device according to claim 5, wherein the heating assembly is sealingly inserted into the partition wall.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Further details and advantages of the present invention will be evident from the following description of embodiments in conjunction with the drawing. Therein:

[0030] FIG. 1 shows a perspective front side view of an embodiment of a ceramic component with the metallization provided thereon;

[0031] FIG. 2 shows a schematic side view of the embodiment according to FIG. 1 with a first embodiment of a contact element;

[0032] FIG. 3 shows a side view according to FIG. 2 for a further embodiment of a contact element;

[0033] FIG. 4 shows a side view according to FIG. 2 with an electrically insulating overmold, and

[0034] FIG. 5 shows a perspective, partially sectional view of an electric heating device that includes several embodiments of the heat-generating element therein.

DETAILED DESCRIPTION

[0035] FIG. 1 shows a cuboid ceramic component 2 which has two opposing main side surfaces 4 spanned by the width B and the length L of the cuboid ceramic component 2. In the direction of the length L and in the direction of the height H, the longer end faces 6 extend. At right angles to this and at right angles to the main side surfaces 4, shorter end faces 8 extend.

[0036] It is evident that metallization strips 10, 12 are provided on the opposite main side surfaces 4. The metallization strips 10, 12 each have an equal width b. This width b corresponds to approximately 5% of the width B of the ceramic component 2. The metallization strips 10, 12 are applied solely to the main side surfaces 4. The metallization strips 10, 12 are generated by sputtering an electrically conductive material onto the ceramic surface of the ceramic component 2. The two metallization strips 10 are assigned to one polarity, the two metallization strips 12 are assigned to another polarity.

[0037] The longer and shorter end faces 6, 8 form a circumferential edge on the cuboid ceramic component 2. Each of the end faces 6, 8 is substantially smaller than each of the main side surfaces 4. Thus, the main side surfaces 4 form those surfaces for the predominant dissipation of the heat generated by the ceramic component.

[0038] FIG. 2 shows a side view of a lateral edge of an embodiment of the present invention with a contact element characterized by reference sign 14. The contact element 14 directly contacts the two opposing metallization strips 10. The contact element 14 is soldered to the metallization strip 10 and is thus connected by a material bond.

[0039] FIG. 3 shows an alternative embodiment. There, the contact element 14 consists of a claw with a central web 16 and opposite legs 18, from which convexly curved contact projections 20 project inwardly, which are connected directly to the surface with metallization strips 10 by clamping. An insulating layer, for example in the form of a plastic film, can be provided between the web 16 and the longer end face 6 in order to prevent electrical contact between the contact element 14 lying on a polarity and the end face 6.

[0040] As illustrated in FIGS. 2 and 3, the power current is introduced only via the metallization strips 10, 12. From there, the power current traverses the ceramic component 2 to the respective other polarity. As a result, the ceramic component 2 heats up.

[0041] In the embodiment shown in FIGS. 2 and 3, there is usually an insulating layer between the metallization strips 10, 12. This insulating layer may form outer surface of the PTC heating assembly.

[0042] FIG. 4 shows a sectional view of a variant in which an insulating layer 22 in the form of a ceramic plate or plastic film is applied to the area of the main side surface 4 not provided with the metal strip 10, 12. The edge region of the insulating layer 22 extending in the longitudinal direction L is overlapped by the legs 18 of the contact element 14 and accordingly is mechanically secured. FIG. 4 further illustrates an over-mold of an electrically insulating plastic, characterized by reference sign 24, which overlaps the rail-shaped contact element 14, as well as an extended edge region of the insulating layer 22 and seals the contact element 14. Thus, the outer surface of the insulating layer 22 forms the heat-emitting outer surface of a PTC heating assembly characterized by reference sign 26. The outer circumferential surface of this PTC heating assembly is essentially formed by the overmold 24. On one edge side, this frame-shaped overmold 24 is protruded by contact lugs formed by the free ends of the rail-shaped contact element 14. This can be trimmed to form a flat contact lug so that only one of the legs 18 or the web 16 projects beyond the overmold 24 as a contact lug.

[0043] The installation of several PTC heating assemblies, constructed in a corresponding manner, in an electric heating device of a motor vehicle for heating a liquid or gaseous medium is illustrated in FIG. 5. In FIG. 5, the heating assembly is identified with reference numeral 116. The electric heating device has a heater housing 100 made of plastic and characterized by reference sign 100. The heater housing 100 forms inlet and outlet ports 102 which define respective inlet and outlet openings 104 leading to a circulation chamber 106 which is fluid-tightly separated from a connection chamber characterized by reference sign 110 by a cover forming a partition wall 108. The partition wall 108 forms receptacles 112, which are formed as female plug-in elements of a fluid-tight plug-in connection which is effected by inserting a sealing collar 114 into the receptacle 112. The sealing collar 114 is typically made of a soft elastic plastic, in particular silicone. The sealing collar 114 may be part of the overmold 24 or formed by a separate overmold around it.

[0044] In the position shown in FIG. 4, the free ends of the contact lugs protrude into the connection chamber 110 and can be electrically connected there, as described in principle, for example, in EP 3 334 244 A1.

[0045] In the embodiment shown here, the cover forms the partition wall 108 which seals the circulation chamber 106 from the connection chamber 110 in a fluid-tight manner and forms the receptacles 112. In the embodiment shown, the cover is inserted into the heater housing as a separate component made of plastic. Other designs are also conceivable in which, for example, a bottom of the heater housing 100 is formed as a separate cover element and the partition wall 108 is integrally formed together with walls of the heater housing 100 defining the connection chamber 110 or the circulation chamber 106 and extending substantially at right angles to the bottom.