EP1912028A1 - Electric heating means, specially for an automobile - Google Patents

Abstract

The arrangement (1) has a heat transmission area for transmission of the produced heat to fluid flowing through the arrangement, where the transmission area has a set of positive temperature coefficient (PTC) units (3) that are arranged in parallel. The PTC units are connected with one another in a force-fit manner in a connection area by using a tie rod. The PTC units run parallel to each other and arranged at a distance from each other. Disks (6) are arranged between the PTC units, and an isolating housing or a frame (2) is made from polyamide (PA66), where the PTC units are made of plastic.

Description

The invention relates to an electrical heating arrangement with PTC elements, in particular for a motor vehicle.

With regard to the design of the PTC heating arrangements, there are essentially two different embodiments.

The first embodiment generally comprises strip or cuboid PTC elements which are arranged between contact plates and / or corrugated ribs, via which the electrical contacting takes place. In this case, the air to be heated essentially absorbs the heat emitted by the PTC elements from the corrugated fins provided for the enlargement of the heat transfer surface. The PTC elements may be plastic or ceramic elements.

An example of such an embodiment is shown in FIG EP 1 522 439 A1 disclosed. Here, the arranged between the contact plates PTC elements and arranged on the outside of the contact plates corrugated fins are held in an electrically insulating plastic frame.

The electrical contacting of the contact sheets can be effected in that the contact plates protrude laterally from the frame and a plug connection is provided, wherein the frame can be designed accordingly. However, the contact sheets can also be connected within the frame with contact rails, which are contacted from the outside, or an electrical conductor is inserted directly into the frame and connected to the contact bars or contact plates.

According to the second embodiment, which differs fundamentally from the first embodiment, a honeycomb body is provided, which consists entirely of a PTC material through which the air to be heated flows. The electrical contacting takes place on two opposite sides of the honeycomb body. An example of such an embodiment is shown in FIG DE 100 60 301 A1 disclosed, wherein the honeycombs are formed as a continuous channels with a square cross-section.

It is an object of the invention to provide an improved electrical heating arrangement with electrical heating elements, in particular PTC elements available.

This object is achieved by an electrical heating arrangement with the features of claim 1. Advantageous embodiments are the subject of the dependent claims.

According to the invention, an electrical heating arrangement is provided, in particular for a motor vehicle, having a heat transfer area for transferring the heat generated to a fluid flowing through the electric heating arrangement, the heat transfer area having a number of flat elements arranged side by side, and the flat elements are non-positively clamped together in at least one connecting region via at least one tie rod. By providing a tie rod, for example, formed by a rod with end-threaded areas and nuts screwed thereto, allows a simple way a purely mechanical assembly (and accordingly disassembly) and also a purely mechanical fixation of the heating grid, which preferably is formed from a plurality of individual elements, in particular preferably by plate-shaped PTC elements (ceramic or plastic), optionally also in combination with other elements. A usually advantageous bonding can in principle - but not necessarily - omitted, since by the tie rod or a sufficiently secure fixation is possible. A purely mechanical assembly and fixation without adhesives or similar. also simplifies recycling of the heater assembly, which is associated with a separation of the individual components.

It is particularly advantageous if the tie rod provides at least a portion of the electrical contact. By way of the tie rod, in particular via one end thereof, a PTC element or possibly also an element serving for the distribution of current, such as a metal strip or the like, can be simply contacted electrically, the end of the tie rod preferably projecting beyond the frame of the heating arrangement. This makes it possible to provide a power supply in a very simple way at a central area. An electrical contact via laterally projecting tongues or similar. can be additionally provided, but preferably omitted, if two tie rods are provided.

The flat elements are preferably at least partially formed by PTC elements, ie the flat elements are formed by composite, for example by said PTC elements, in particular conventional PTC bricks glued in between the metal strips and / or corrugated ribs that make electrical contact.

Preferably, in the heater grid, i. provided in the heat transfer area, at least one through opening for the tie rod. This opening can be located both at the edge, in particular in the case of two or more openings, or in a central area. Particularly preferred two tie rods and thus two through openings are provided in the heater.

Preferably, exactly two openings are provided in each PTC element-in the case of plate-shaped PTC elements-or in the heating grid, through which an electrically conductive tie rod protrudes. However, more than two openings per PTC element or heating grid and correspondingly many electrically conductive tie rods can be provided in order to enable different heating stages in which different areas of the PTC elements or the heating grid are traversed by current and thereby generate heat. In principle, isolated tie rods are also possible for additional fixation, which serve exclusively for fixing and thus avoiding vibrations.

Preferably, a plurality of PTC elements is provided, wherein the PTC elements are arranged parallel to each other and spaced from each other. Such a configuration in conjunction with tie rods allows a relatively simple extension of the heater assembly in the longitudinal direction of the tie rods, but the frame must be adjusted accordingly.

If a plurality of PTC elements arranged in parallel are provided, spacer elements, preferably also likewise pushed onto the tie rod, are preferably arranged between the individual PTC elements Slices, arranged. The spacer elements have for this purpose an opening through which the corresponding tie rod protrudes. In this case, the outer or inner dimensions of the openings preferably correspond. The spacer elements are preferably electrically conductive, so that a large-area electrical contacting of the intermediate PTC elements is ensured.

The electrically conductive tie rods, as well as the electrically conductive spacer elements, particularly preferably in the form of discs, are preferably made of steel, stainless steel, brass, copper, silver-plated copper. In principle, an electrically conductive coating which has sufficient conductivity is sufficient, so that a more cost-effective base material, which has sufficient strength and on which the coating can be reliably applied, can be used for the tie rods and / or spacer elements.

Preferably, a PTC element-disc arrangement is provided on the tie rods with a plurality of alternately arranged PTC elements and discs or spacers which correspond in function to those of discs.

The PTC element-disc arrangement preferably ends on the outside in each case with a disk or another spacer element.

For bracing the PTC elements and thus ensuring the electrical contact is preferably screwed to at least one end of the tie rod, which is threaded, or at least one end of the threaded rod formed as a tie rod at least one nut.

Preferably, one end of the tie rod is head-like in diameter expanded and thus forms an end stop for a PTC element disc arrangement, so that the assembly is facilitated because only at one end of the tie rod fixation after threading of the PTC Elements and discs must be provided.

Preferably, an electrical connection is prepared at one end of the tie rod, so that during assembly a quick and easy electrical contact is possible.

The PTC element is preferably a plastic PTC element. Such PTC elements can be produced inexpensively in almost any shape. In principle, the use of ceramic PTC bricks with parallelepiped shapes is also possible, particularly preferably in a composite.

The frame is preferably made of polyamide, more preferably PA66, and is injection molded. It can be formed with a corresponding embodiment, but in particular also in several parts, wherein the individual parts can be connected to each other in a known manner, for example by means Verclipsens or screwing. In this case can be done in the frame by connecting the parts at the same time a fixation of the rod-PTC elements-disc arrangement.

Heating arrangements according to the invention can be provided both as a heater in conjunction with a conventional air conditioner or a conventional heater and in isolation.

Fig. 1

eine schematische Darstellung einer erfindungsgemäßen Heizungsanordnung,

Fig. 2

eine Draufsicht auf ein PTC-Element der Heizungsanordnung von Fig. 1,

Fig. 3

eine Draufsicht auf eine Scheibe der Heizungsanordnung von Fig. 1,

Fig. 4

eine Seitenansicht einer Gewindestange der Heizungsanordnung von Fig. 1,

Fig. 5

eine erste Variante einer Gewindestange,

Fig. 6

eine zweite Variante einer Gewindestange,

Fig. 7

eine andere Ansicht der Gewindestange von Fig. 6, und

Fig. 8

eine dritte Variante einer Gewindestange.

In the following the invention with reference to two embodiments, in part with reference to the drawings, explained in detail. In the drawing show:

Fig. 1

a schematic representation of a heating arrangement according to the invention,

Fig. 2

1 is a top view of a PTC element of the heating arrangement of FIG. 1,

Fig. 3

1 a top view of a pane of the heating arrangement of FIG. 1,

Fig. 4

1 is a side view of a threaded rod of the heating arrangement of FIG. 1,

Fig. 5

a first variant of a threaded rod,

Fig. 6

a second variant of a threaded rod,

Fig. 7

another view of the threaded rod of Fig. 6, and

Fig. 8

a third variant of a threaded rod.

A heater assembly 1 according to the embodiment serves as a heater in an automotive air conditioner, being arranged in the air flow direction according to a conventional heater. The heating assembly 1 has a frame 2 made of plastic, in this case PA66, which is injection-molded. In the frame, a plurality of plate-shaped plastic PTC Elernenten 3 are arranged parallel to each other and spaced from each other, so that the air flowing through the heater assembly 1 air is distributed to the individual gaps between the PTC elements 3 and the same on both sides of air to be flowed around. Due to the configuration of the PTC elements 3, they are also referred to as "flat elements".

As can be seen in FIG. 2, the PTC elements 3 have an elongate shape with narrow sides ending in a radius, wherein a circular opening 4, for example a bore, is provided in the center of curvature. In the assembled state protrude through the openings 4 rods, in this case threaded rods 5, whose outer diameter corresponds to the opening diameter. The threaded rods 5 are made according to the embodiment of stainless steel. However, any other electrically conductive materials which have sufficient stability are also possible, in particular steel, brass, copper, silver-plated copper. In principle, an electrically conductive coating which has sufficient conductivity is sufficient. The rods form tie rods, which serve, inter alia, the bracing of the PTC elements 3.

Between the individual PTC elements 3, electrically conductive disks 6 (see FIG. 3) are arranged on the threaded rods 5, which ensure a constant distance between the PTC elements 3 and have an inner diameter corresponding to the threaded rod outer diameter. The outer diameter of the discs 6 is in the present case dimensioned so that it corresponds to the curvature diameter of the rounded portion of the PTC elements 3, so that viewed from the narrow side a compact, columnar shape and also in the air flow direction, a block-like shape of the PTC element discs The material of the disks 6 can be the same material as the threaded rods 5.

To fix the PTC element-disc arrangement on the threaded rods 5, a nut 7 is arranged in each case after the final disc, which braces the entire assembly. Any backups of the Nuts 7 are - although not shown in the drawing - possible, for example. Locknuts, spring washers or split pins.

The threaded rods 5 protrude laterally beyond the frame 2 on one side 8, where they can be electrically contacted in a simple and in principle known manner, i. the tie rods serve as electrical contacts. The entire assembly of the heater assembly 1 takes place here purely mechanically, which is also very advantageous in terms of a possible recycling and the disassembly associated therewith.

The threaded rods 5 need not necessarily be simply formed threaded rods, as shown in FIG. 4. Alternatively, more specifically adapted to the application threaded rods are possible, for example. As shown in Fig. 5, with a Radsok connection, as shown in Fig. 6 and 7, with an attached directly at the end electrical connection in the form of a perforated disc with tab , or as in Fig. 8 with a widened end, so that on one side the mother can be omitted, with combinations are possible, in particular the first and last variant. However, other electrical contacting systems of the threaded rods are possible. Likewise, a threaded thread does not necessarily have to be provided in the case of the threaded rods; instead, a correspondingly designed end region is sufficient for screwing on a nut.

In principle, other measures, such as. Pushed onto the rods springs are conceivable for bracing the PTC element disc arrangement, so that as a conclusion of rods and other means, such as snap rings, are possible and no thread must be provided.

According to the second embodiment, not shown in the drawing, in order to enable a flat, electrical contacting, PTC stones provided in place of the sheet-formed plastic PTC elements, which are arranged in known manner by means of an electrically conductive adhesive between metal strips. Corrugated ribs are arranged between the individual metal strips in order to enlarge the heat-transferring surface. The corrugated ribs can be glued or soldered to the metal strip. In order to clamp and fix the entire arrangement, in the present case, a single rod is guided centrally through holes in the metal strip and the corrugated ribs. The holes are presently designed such that a meaningful, alternating, electrical contacting of the metal strip on the rod is possible. The second, other contact takes place here in a known manner via an outer, a tongue-forming end of not contacted via the holes metal strip. Alternatively, an electrical contact via a second rod would be possible, wherein the bore dimensions are to be interpreted in the metal strip such that only one metal strip is in contact with one of the rods.

The rod or rods are used in addition to the electrical contact and the bracing of the heating grid, at least in the context of assembly, so that after the gluing, with still uncured adhesive, no displacement of the individual components to each other is possible. Preferably, however, even after curing of the adhesive by the rod (n) applied pressure on the heater is present. In addition, the ends of the bars, when projecting beyond the frame, can also serve to position and fix the heating grid in the frame. For this purpose, for example, a nut can be screwed on the outside of an end of the rod, of course, a fixation is possible on both sides.

In order to avoid short circuits, discs can also be used in those holes that are not the electrical contact of the corresponding Metal strip serve, ie the insulating discs separate the metal strip from the guided through the bore rod. The discs can be used during the assembly of the heater grid.

With a corresponding design of the metal strips and PTC blocks, in principle, a "loose" arrangement of the same is possible, which is held together only by an exciting force, which is applied by the or acting as tie rod rods.

Claims (18)

Electric heating arrangement (1), in particular for a motor vehicle, having a heat transfer area for transferring the heat generated to a fluid flowing through the electric heating arrangement, the heat transfer area having a number of flatly arranged elements arranged next to one another, characterized in that the flat elements in at least one Connection region are clamped together by at least one tie rod non-positively. Heating arrangement according to claim 1, characterized in that the tie rod provides at least a portion of the electrical contact. Heating arrangement according to claim 1 or 2, characterized in that the flat elements are at least partially formed by PTC elements. Heating arrangement according to claim 3, characterized in that the flat elements are at least partially formed by electrically conductive strips or plates and / or corrugated fins. Heating arrangement according to claim 4, characterized in that the flat elements are formed by glued together PTC elements and electrically conductive strips or plates and / or corrugated fins. Heating arrangement according to one of the preceding claims, characterized in that at least one through opening (4) is provided for the tie rod in and / or at the edge of the heat transfer area. Heating arrangement according to claim 6, characterized in that two tie rods and two through openings (4) are provided. Heating arrangement according to one of the preceding claims, characterized in that the heating arrangement has at least one plate-shaped PTC element (3). Heating arrangement according to claim 8, characterized in that a plurality of PTC elements (3) is provided, wherein the PTC elements (3) are arranged parallel to each other and spaced from each other. Heating arrangement according to claim 9, characterized in that between the individual PTC elements (3) spacer elements, in particular discs (6) are arranged, which are pushed onto the tie rods. Heating arrangement according to claim 10, characterized in that the spacer elements are electrically conductive. Heating arrangement according to one of the preceding claims, characterized in that on the tie rods a PTC element-disc arrangement with a plurality of alternately arranged PTC elements (3) and discs (6) is provided. Heating arrangement according to claim 12, characterized in that the PTC element-disc arrangement ends on the outside in each case with a disc (6). Heating arrangement according to one of the preceding claims, characterized in that at least one end of the tie rod at least one nut (7) is screwed. Heating arrangement according to one of the preceding claims, characterized in that at one end of the tie rod or an electrical connection is prepared. Heating arrangement according to one of the preceding claims, characterized in that the PTC element (3) is a plastic PTC element. Heating arrangement according to one of the preceding claims, characterized in that the electrical heating arrangement (1) has an insulating housing or a frame (2). Heating arrangement according to claim 17, characterized in that the frame (2) made of polyamide, in particular of PA66, injection molded.

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