EP1253032B1 - Electrical heating device with a heater block mounted in a frame - Google Patents

Abstract

The device has a heating block (1) with several parallel electrical heating elements and intermediate heat conducting ribs and a frame in which the heating block is mounted with two longitudinal legs (4a,4b) spanning the block and two cross-legs (5a,5b). The cross-legs have enclosure sections on their ends with which they enclose the corresponding longitudinal leg ends.

Description

The invention relates to an electric heater with a heating block, which includes a plurality of parallel electrical heating elements and intermediate heat conducting ribs, and a frame in which the heating block is held and having two block-clamping trained longitudinal leg and two perpendicularly arranged transverse leg. Such electrical heaters are used for example in heating systems of motor vehicles for heating a vehicle interior. As heating elements often strip-shaped PTC heating coils are used, which are constructed of two sheets and between these held in openings of a sealing profile PTC elements.

At one in the Laid-open publication DE 197 06 199 A1 described PTC heating device of this type, the frame consists of two circumferential, parallel to the Heizblockebene opposite frame parts made of thermoplastic material, wherein the longitudinal legs are formed block Verspannend that they easily in the relaxed, unassembled state from the central region to its two end curved outside. In the assembled state brace the longitudinal leg due to their elasticity, the heating block between them. Furthermore, an alternative is described in which the frame consists of two frame parts, which result by dividing the transverse limbs along a plane perpendicular to the Heizblockebene and the transverse limbs dividing plane. In this case, the block bracing is done by connecting the frame parts by means of spring clips or spring-loaded screws.

At one in the EP 0 893 937 A2 discloses PTC heater of similar design, the transverse legs of the block-holding frame are split longitudinally at least at their ends, and the longitudinal legs are provided at their corresponding ends with at least one wedge-like area and held clamped with the respective wedge surfaces between the end portions of the transverse legs. Preferably, the wedge surfaces are realized in that the longitudinal legs are formed as a profile with trapezoidal or triangular cross-section. During assembly, the heating block is inserted into the frame, after which the divided Querschenkelendbereiche be connected to each other via connecting means and exert on the wedge surfaces a heating block bracing force on the longitudinal leg. The frame legs are preferably formed as aluminum extruded profiles. As connecting means serve screws or rivets.

From the EP 0 350 528 A1 , Which represents the closest prior art, a heating device is known, the transverse frame members embrace the ends of the longitudinal and against each other spring-loaded frame members form-locking and securing them in the transverse direction outwards. This allows a simple and largely automatable pre-assembly of the frame. However, a more extensive attachment appears desirable.

The object of the invention is to provide an electric heater of the generic type, which can be assembled particularly advantageously and largely automated as needed.

The invention solves this problem by providing an electric heater with the features of claim 1. The subclaims relate to advantageous developments.

In this heater, the transverse legs are provided at their ends with Umfassungsabschnitten with which they the corresponding longitudinal leg ends in the transverse direction to the outside. This measure, in conjunction with the block-spanning training of the longitudinal leg allows a largely automated pre-assembly of the heating block with the surrounding and holding frame. For this purpose, the two longitudinal legs can be applied to the heating block and then introduced on one side between the two enclosing portions of a transverse leg. Subsequently, the other transverse leg can be placed under endseitigem, block Verspannend compression of the longitudinal leg. As soon as he also includes the corresponding longitudinal leg ends with his two Umfassungsabschnitten, the structure is self-holding pre-assembled, since the longitudinal leg compress the heating block and thereby stabilize the structure and the longitudinal leg ends are simultaneously secured against yielding by the Umfassungsabschnitte the transverse leg. In this self-holding preassembled state then all necessary fasteners can be made without the pre-assembled body by hand or must be mechanically held together.

The invention is characterized in that the attachment points for connecting at least a part of the frame legs with each other and / or for connecting at least a part of the electric heating elements with one or more of the Rahmenschenkein from a common and vertical to the Heizblockebene mounting direction can be produced. Accordingly, all fasteners in a common, perpendicular to the Heizblockebene mounting direction. By this measure, the production of the required (for the long life) attachments can be done automatically with very little effort.

In an advantageous embodiment of the invention according to claim 2, at least one of the two transverse legs is designed as a ring part. This can be pushed laterally on the held together structure of heating block and longitudinal leg, wherein the annular sections in the longitudinal leg at the same time act as the Umfassungsabschnitte, which therefore do not need to be specially trained. The ring shape allows optimal power distribution and a low component weight.

In a development of the invention according to claim 3, the attachment points are realized by self-tapping screws or laser welding. These compounds are very tolerant to production, as they are after the pre-assembly of the invention to the desired. Points can be made without having to pay attention to a precise mutual positioning of the parts to be joined. At the same time effect These types of fastening ensure a secure mechanical and electrical connection.

An advantageous development according to claim 4 provides that the attachment points lie in a common plane.

In a further development, according to claim 5, a transverse limb and the heating element connection ends to be contacted with it are designed such that these heating element connection ends can be fastened to a corresponding contacting surface of the transverse limb in the said common installation direction, in which all other fixings are made.

Fig. 1

eine perspektivische Draufsicht auf eine PTC-Heizeinrichtung mit einem Heizblock und einem diesen haltenden Rahmen für eine Kraftfahrzeug-Heizungsanlage,

Fig. 2

eine Draufsicht auf die in Fig. 1 linke Stirnseite der Heizeinrichtung,

Fig. 3

eine Draufsicht auf einen als Ringteil ausgebildeten Querschenkel des Rahmens von Fig. 1,

Fig. 4

eine Perspektivansicht des anderen Querschenkels des Rahmens von Fig. 1,

Fig. 5

eine Seitenansicht eines der im Heizblock von Fig. 1 verwendeten PTC-Heizregister und

Fig. 6

eine Perspektivansicht der mit einem Kunststoff-Außenrahmen komplettierten Heizeinrichtung von Fig. 1.

An advantageous embodiment of the invention is illustrated in the drawings and will be described below. Hereby show:

Fig. 1

a perspective top view of a PTC heater with a heating block and this holding frame for a motor vehicle heating system,

Fig. 2

a top view of the in Fig. 1 left end of the heater,

Fig. 3

a plan view of a formed as a ring part transverse leg of the frame of Fig. 1 .

Fig. 4

a perspective view of the other transverse leg of the frame of Fig. 1 .

Fig. 5

a side view of the one in the heating block of Fig. 1 used PTC heating coil and

Fig. 6

a perspective view of the completed with a plastic outer frame heater of Fig. 1 ,

The electric heater shown is particularly suitable as additional heating in a motor vehicle to heat leading into the vehicle interior air, as long as or as far as a heating and cooling circuit of a combustion engine usually used in the motor vehicle used as a drive heat is not sufficient. As in Fig. 1 to recognize, the heater has a heating block 1, which is composed of a plurality of spaced apart adjacent electrical heating elements in the form of strip-shaped PTC heating coils 2 and introduced between these, heat-conducting corrugated fins 3.

The rectangular heating block 1 is held in a surrounding frame, which on each opposite block sides two parallel to the heating elements arranged longitudinal legs 4a, 4b and two perpendicular thereto arranged transverse legs 5a, 5b. All four frame legs 4a, 4b, 5a, 5b are preferably made of an aluminum material. At about half the height of the heating block, two adjacent PTC heating coils are spaced apart from one another by a resilient strip 6 by a spring strip 6 having a plurality of oppositely spread spring tongues. The spring strip 6 is used to achieve an elastic manufacturing tolerances compensating, backlash-free Heizblockaufbaus and is just like the corrugated fins made of thermally conductive and electrically conductive material.

The two longitudinal legs 4a, 4b consist of a C-profile, as for the one profile 4a Fig. 2 visible, with its open side from the heating block 1 outwardly facing. The C-shaped longitudinal leg sections 4a, 4b are prefabricated slightly bent from the middle region to the two ends outwards, ie toward their open profile side. The material thickness is selected, for example, in the range between 1 mm and 2 mm so that the longitudinal legs 4a, 4b can be pressed during mounting in the direction of a straight course, as a result of which they are able to compress the heating block structure 1 without play and thereby to clamp it.

Matching to this longitudinal leg design, a special design of the transverse leg 5a, 5b is provided, which is suitable to pre-assemble the Heizblockaufbau 1 can then make connections provided on the preassembled structure without this must be held together by hand or mechanically. For this purpose, the transverse legs 5a, 5b at their two ends, ie end faces, respective enclosing portions 7a, 8a and 7b, 8b. These include in the assembled state of the heating block, as in Fig. 1 Thus, the latter are secured against moving away in the transverse direction to the outside, ie the transverse legs 5a, 5b hold the longitudinal legs 4a, 4b in their tensioned mounting state in which they clamp the heating block 1.

The one, in Fig. 1 left transverse leg 5a is as out Fig. 3 seen as a closed ring or bracket part with two stiffening transverse webs 13, 14 is formed. This design has the advantage of ease of manufacture, ease of assembly and optimum power distribution with low weight. The Umfassungsabschnitte 7a, 8a for embracing the longitudinal legs are formed in this rectangular transverse leg ring of the narrow side portions.

The other transverse leg 5b is, as from the Fig. 1 and 4 seen, formed by a U-shaped profile, the open side facing away from the Heizblockaufbau 1 to the outside. At its ends is this U-transverse leg profile 5b on the one hand with a first 90 ° -Abwinklung 7b, 8b provided. These two angled portions 7b, 8b extend in planes lying perpendicular to the longitudinal axis of the profile and form the enclosing sections for externally embracing the corresponding longitudinal leg ends 11, 12. On the other hand, a second 90 ° bend 15, 16 is formed on each end of this transverse leg 5b. These two bends 15, 16 extend in a common plane parallel to the heating block plane and lie in the mounted state against the in Fig. 1 front side of the corresponding longitudinal leg ends. Each of the two angled portions 15, 16 is provided with two attachment openings 17, 18.

The second transverse leg 5b also serves as a common connection rail for electrically contacting each one sheet of each second PTC heating register of the heating block 1 with a first pole of an associated electrical power supply. For this purpose, a U-longitudinal edge 19 of this transverse leg 5b acts as a connecting rail contacting surface, which is parallel to the heating block level at the in Fig. 1 extends front block side. Fig. 5 shows one of the to be connected to this connection rail 19 PTC heating coil. Like the other PTC heating coils, these PTC heating coils have the above-described conventional structure consisting of two contact plates 20, 21, between which several PTC elements are located side by side in openings of a sealing profile 22, in which the contact plates 20, 21 in lateral longitudinal grooves are guided. In the PTC heater to be connected to the busbar 19, as shown in FIG Fig. 5 to recognize that a contact plate 20 at the corresponding terminal end a contact angle 23, which is formed by a double 90 ° -Abwinklung first by 90 ° about the transverse axis and then by 90 ° about the vertical axis of the strip-shaped PTC-Heizregisters 2. As a result, the contacting angle 23 at the end a contacting surface 23 a, with which he in the assembled state of Fig. 1 plan rests on the transverse leg contacting surface 19, wherein the Contacting surface 23 a of the Heizregister-contacting angle 23 is provided with a mounting opening 24.

The other, arranged in the block in the block PTC heating coil, which are not contacted with the busbar 19, have at the opposite end in each case one of its two sheets formed contact lug 25, as from the Fig. 1 and 2 to recognize. About this is a connection to the other pole of the supply voltage using a corresponding, not shown harness. In this case, the PTC heating register 2 can be electrically connected in a desired manner by a control device, not shown, for example arranged block-external control consisting of a drive logic and power electronics, for example, parallel or serial or in a mixed form. The connection for the busbar 19 can take place via a connecting angle 26, which is integrally formed on the one longitudinal limb 4a and is located on the same block side as the connecting lugs 25, so that all cable connections can be made on a common block side. The metallic design of the longitudinal and transverse legs 4a, 4b, 5a, 5b ensures the electrical connection between the connection bracket 26 and the connecting rail 19th

The described design of the heating block 1 shown with the surrounding and holding frame 4a, 4b, 5a, 5b offers great advantages in terms of a largely automatable assembly. This can be done as follows. First, the heating block 1 is loosely constructed in the usual way by alternately, suitable juxtaposition of corrugated fins 3 and PTC heating coils 2 with the central spring strip 6. The loose block structure is then compressed by two externally pressing on the longitudinal leg 4a, 4b clamping means until the transverse sides 5a, 5b can be easily plugged on the two transverse sides. After loosening the tensioning means, the transverse limbs 4a, 4b hold the longitudinal limbs 5a, 5b in their block-tightening state, by engaging with their enclosing sections 7a, 8a, 7b, 8b, the longitudinal leg ends 9, 10, 11, 12 hold. In this state, consequently, the block structure 1 is tension-free braced and secured by the four frame legs 4a, 4b, 5a, 5b self-locking against falling apart. The block-centered spring strip 6 in this case ensures a uniform distribution of the frame 4a, 4b, 5a, 5b provided compressive force and compensates for manufacturing tolerances.

Thereafter, the required fasteners or mechanical and electrical connections can be made on the block structure, without the latter having to be held together by hand or by machine. Of particular advantage here is that due to the described block and frame design all attachment points can be operated from a common mounting direction ago, and that of the in Fig. 1 In addition, all these attachment points are practically in a common plane parallel to the block plane. This includes both fasteners 27 of the heating register contact angle 23 on the connecting rail 19 and a respective pair of fasteners 28, 29 for fixing the two longitudinal legs 4a, 4b on the connecting rail transverse leg 5b.

In the example shown, all these fasteners 27, 28, 29 are realized by self-tapping screws, which are easily automated e.g. can be attached by a corresponding automatic screwdriver. The latter can be done very easily, if, as mentioned, all screw fasteners are made from one direction and in a common plane, i. at the same height.

Other advantages of this type of fastening are that they represent an optimal electrical connection as well as a safe, backlash-free mechanical connection, for the release of a higher torque than for screwing is required. In addition, this type of attachment is completely independent of manufacturing tolerances, since no corresponding mounting holes are to be brought into agreement, but the screw can be introduced in each case, where after the pre-assembly, the associated mounting opening 17, 18, 24 is located. As a mounting alternative, for example, offers laser welding, which is also tolerant of production and easy to automate and leads to reliable, backlash-free mechanical and electrical connections.

Further advantages of the block frame design according to the invention are the reusability, if the four frame legs 4a, 4b, 5a, 5b are made as described exclusively from an aluminum material, by the nature of the longitudinal and transverse legs 4a, 4b, 5a, 5b low weight of the structure and the comparatively low production costs. It is understood that in addition to the heating device described above further realizations of the invention are possible, for example, one in which both transverse legs are formed as a closed ring part. Instead of the mentioned PTC heating coil, other conventional electrical heating elements can be used depending on the application and, instead of the mentioned strip shape, any other shape suitable for block construction is possible for the electrical heating elements.

As in Fig. 6 shown, the Heizblockrahmenaufbau 1a produced as described can be surrounded with a plastic outer frame, which serves for sealing, insulation and support in the heating system and consists of a temperature-resistant plastic material. In this case, it is possible to integrate the cable harness mentioned for the electrical connection of the PTC heater 2 in these outer frame 30, ie receive it, so that the block frame structure 1a itself no electrical plug connections are required, which keeps the footprint low. The outer art frame 30 also has a defined air flow window 31, which ensures that the air flow to be heated only by the range of heated by the PTC heating coils 2 corrugated fins 3 passes and no unwanted bypass air streams occur, for example in the region of the frame legs or a cable harness opening.

Claims (5)

1. Electrical heating device, in particular for a motor vehicle, with

   - a heating block (1) with several electrical heating elements (2) arranged in parallel, and heat conducting fins (3) arranged in between, and

   - a frame, in which the heating block (1) is held, with two longitudinal members (4a, 4b) designed to tension the block, and two transverse members (5a, 5b) arranged perpendicular thereto, wherein

   - the transverse members (5a, 5b) have embracing sections (7a, 8a, 7b, 8b) at their ends, with which they embrace the corresponding ends of the longitudinal members (9, 10, 11, 12) in lateral direction while interlocking these in transverse direction against the exterior,

   characterised in that
   the fixation sites, connecting at least one part of the members of the frame (4a, 4b, 5a, 5b) with each other and/or connecting at least one part of the electrical heating elements (2) with one or several of the members of the frame (4a, 4b, 5a, 5b), can be manufactured from a common direction of assembly, which is arranged perpendicular to the plane of the heating block.
2. Electrical heating device according to claim 1,
   further characterised in that
   at least one of the transverse members (5a, 5b) is designed to be a closed-loop part.
3. Electrical heating device according to claim 1 or 2,
   further characterised in that
   the fixation sites (27, 28, 29), connecting at least one part of the members of the frame (4a, 4b, 5a, 5b) with each other and/or connecting at least one part of the electrical heating elements (2) with one or several of the members of the frame (4a, 4b, 5a, 5b), are implemented by self-cutting screws (27, 28, 29) or laser-welded joints.
4. Electrical heating device according to claim 1,
   further characterised in that
   the fixation sites (27, 28, 29) are arranged in a common plane.
5. Electrical heating device according to claim 1 or 4,
   further characterised in that

   - at least one transverse member (5b) is designed to be an electrically conducting collective line of the heating elements with a contacting surface (19), which is arranged in parallel with the plane of the heating block, and

   - the heating elements, which are connected to the collective line, have a contacting angular piece (23) with a contacting surface (23a) at their corresponding contacting ends, through which they are connected with the contacting surface (19) of the collective line.

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