EP2462780A1

EP2462780A1 - Functional module and method for producing the functional model

Info

Publication number: EP2462780A1
Application number: EP10743075A
Authority: EP
Inventors: Jan Ihle; Werner Kahr; Volker Wischnat; Steffen Mehlig
Original assignee: Epcos AG
Current assignee: TDK Electronics AG
Priority date: 2009-08-07
Filing date: 2010-07-30
Publication date: 2012-06-13
Also published as: US20120175149A1; DE102009036620A1; WO2011015535A1; JP2013501331A

Abstract

The invention relates to a functional module and a method for producing a functional module. The functional module comprises an outer tube having a first and second end face and an inner surface, an inner tube having a first and second end face and a shell surface disposed within the outer tube, and at least one molded part disposed in a form-fit manner between the inner surface of the outer tube and the shell surface of the inner tube, and comprising a material having a positive temperature coefficient of electrical resistance. The first end face of the inner tube and the outer tube is disposed on an electrically isolative substrate and the molded part is thereby fixed between the outer tube and the inner tube by clamping force.

Description

description

Function module and method for producing the

function module

The invention relates to a functional module and a method for producing the functional module.

Media or components can by means of a thermal

Contact with materials that have a positive

Temperature coefficients of electrical resistance (PTC materials) have to be heated. Such PTC materials can hitherto be formed as disks or rectangular elements. If the media is not in direct contact with the PTC material but is in a container or housing, there may be reduced contact areas between the PTC materials and the enclosures if the enclosures or containers have curved surfaces. A small

Contact area between the PTC material and the housing has a low efficiency due to the unfavorable

Surface volume ratio result. So far, for example, circular pipes through which fluids flow or flow around can only be heated with low efficiency by means of PTC materials. This causes longer

Heating times and higher heating capacities.

Furthermore, PTC materials can be used in devices as

Overload protection can be used. Again, so far no elements with a curved surface could be provided.

An object to be solved is to provide a functional module which has a high efficiency. These Task is a function module according to the

Claim 1 solved. Further embodiments of the

Function module, a method of making this

Functional module and its use are the subject of further claims.

According to one embodiment, a functional module

provided an outer tube with a first

End face, a second end face and an inner surface, an inner tube having a first end face, a second end face and a lateral surface, which within the

Outer tube is arranged, at least one molded body which is positively arranged between the inner surface of the outer tube and the lateral surface of the inner tube and a material having a positive temperature coefficient of the electric

Resistive comprises. Here are the first

Front side of the outer tube and the first end of the

Inner tube on an electrically insulating substrate

arranged and fixed the molded body between the outer tube and the inner tube by clamping force.

With this arrangement, a permanent contact of the molding by the outer tube and the inner tube and

at the same time provided a positive connection of the molding between the outer tube and the inner tube without the use of adhesives or additional components. The molded body can thus be positively and fully connected to the outer tube and the inner tube, and thus enable a good thermal and / or electrical contact.

The electrically insulating substrate may include a material having a high temperature stability. For example, plastics may be selected which may continue to be filled with glass fibers. Examples of plastics are polyphenylene sulfide (PPS) or

Polytetrafluoroethylene (PTFE).

The arrangement of the first end face of the inner tube and the first end face of the outer tube on the electrically insulating substrate becomes a short circuit on the one hand

prevented, which could arise when applying a voltage to the inner tube and the outer tube.

Furthermore, the inner tube and the outer tube

be positively connected. Due to the frictional connection of the molded body can be pressed by means of the inner tube into the outer tube and thus a permanent electrical

Contact to be realized. The forces necessary for this purpose can be transmitted by means of the electrically insulating substrate on which the inner tube and the outer tube are arranged. With the electrically insulating substrate can on the inner tube a compressive stress for pressing the

Inner tube in the molding and thus be generated for pressing the molding in the outer tube. At the same time, a tension equal to the compressive stress is generated on the outer tube, since the outer tube is also mechanically connected to the electrically insulating substrate,

for example by means of angled tabs. The sum of all occurring forces is thus zero.

Due to the frictional connection between inner tube and outer tube may continue to occur

Thermal expansions of the different materials of the

Outer tube, the inner tube and the molding due to Temperature changes and thus possibly associated mechanical damage are well balanced.

The lateral surface of the inner tube encloses the wall of the

Inner tube having an inner surface, an outer surface and a wall thickness.

Furthermore, the inner tube may have a gap in the longitudinal direction of the inner tube. The gap in the lateral surface of the

Inner tube causes a disruption of the lateral surface along the entire inner tube.

The lateral surface of the inner tube and the inner surface of the

Outer tube may include a curvature, at least in some areas. So it can be cylindrical, with oval

Average molded inner tubes and inner surfaces of outer tubes are used, or other arbitrarily shaped inner tubes and inner surfaces of outer tubes, which may be formed symmetrically or asymmetrically and whose curvature may be interrupted by a kink.

The molded body, which is arranged in a form-fitting manner between the lateral surface of the inner tube and the inner surface of the outer tube, likewise has the shape of a tube. He is like that

clamped between the outer tube and the inner tube, that an additional fixation by, for example

Adhesive connections is not necessary. It can also several, for example, up to ten moldings between the

Inner surface of the outer tube and the lateral surface of the

Be arranged inside tube. These are then arranged one behind the other, so that each shaped body comprises an interface with the lateral surface and the inner surface. The inner surface of the outer tube and the outer surface of the

Inner tube can each have a diameter. The diameter of the inner surface may be from the first end side to the second end side of the outer tube

rejuvenate. Thus, the diameter at the first end face of the outer tube is greater than at the second end face of the

Outer tube, wherein the diameter of the inner surface of the outer tube decreases steadily from the first end side to the second end side. Furthermore, the diameter of the lateral surface may taper from the first end side of the inner tube to the second end side of the inner tube. Thus, the diameter at the first end side of the inner tube is larger than the diameter at the second end side of the inner tube. The first end face of the inner tube is located on the same side as the first end face of the outer tube. Thus, the course of the taper of the inner tube is parallel to the

Rejuvenation of the inner surface of the outer tube. The inner tube and the inner surface of the outer tube thus have, for example, a shape that is shaped in the manner of a truncated cone.

By this shape of the inner surface of the outer tube can be the form-fitting to the inner surface of the outer tube

fit molded bodies well into the outer tube without slipping through the outer tube. Likewise, the inner tube can be well arranged within the molding without slipping through the molding. Thus, the fixation of the molded body between the outer tube and the inner tube is improved by clamping force. Furthermore, possibly occurring thermal expansions of

various materials of the outer tube, the inner tube and the molding due to temperature changes and thus possibly accompanied by mechanical damage.

The outer tube may further comprise an outer surface.

This may be formed according to the inner surface and have a diameter which is at the first end of the

Outer tube is larger than at the second end of the

Outer tube. The outer surface of the outer tube may be further formed such that the diameter of the outer surface at the first end side is as large as the diameter at the second end side of the outer tube, so that the inner surface of the outer tube in the manner of a truncated cone and the

Outer surface of the outer tube is formed cylindrically. The material of the outer tube and the inner tube may be selected from a group comprising metals and metal alloys. For example, can be selected as the material aluminum, copper or as a metal alloy brass. These

Metals can be used as electrodes for contacting the

Serve shaped body.

Furthermore, the inner tube may be formed resiliently. This effect is made possible by the existing gap in the lateral surface and can be further improved, for example by using a spring steel. This will be the

Molded body pressed by the inner tube in the outer tube by increased clamping force and thus improves the fixation of the molding between the outer tube and the inner tube. The thermal and / or electrical contacting of the molded body by the outer tube and the inner tube is characterized

improved. The fixation and positive contact is permanently stable, but not rigid, which

possible mechanical damage, such as Stress cracks can be avoided by different thermal expansions of the materials. Thus, too

Material fatigue can be reduced. The molded body, the outer tube and the inner tube may be in thermal contact with each other. Furthermore, a thermally conductive paste can be arranged between the outer surface of the inner tube and the shaped body and / or between the shaped body and the inner surface of the outer tube. This is a good thermal contact between the

Molded body and the inner tube and / or between the molded body and the outer tube ensures, so that the heat transfer between the inner tube and the molded body and the outer tube and the molded body is optimized. The heat transfer is further due to the adapted shape of the molded body to the inner surface of the outer tube and to the lateral surface of the

Inner tube improves, as a large-scale thermal

Contact between the molding and the inner tube and the outer tube is present.

For the thermally conductive paste, a material comprising particles incorporated in polymers can be selected. The particles may be, for example, thermally conductive

Metal particles, graphite particles or alumina particles. These particles make for a good one

Thermal conductivity of the between the molding and the

Inner tube and arranged between the molding and the outer tube paste. Furthermore, the outer tube may have a first contact element and the inner tube may have a second contact element for generating an electric current. It can be the first

Contact element and the second contact element through the protrude electrically insulating substrate so that the contact elements can be contacted externally. The

Contact elements protrude through the substrate in such a way that they do not touch and are therefore insulated from one another. The contact elements may be formed, for example, as sheets with terminal lugs, so that, for example, commercially available tabs or crimp terminals can be connected to the contact elements. Thus, a voltage can be applied to the molded body via the outer tube and the inner tube and the respective contact elements.

The taper of the inner surface of the outer tube and the

The lateral surface of the inner tube can be connected to a rotation axis of the

Inner tube and an axis of rotation of the outer tube have an angle which is selected from a range which includes 1 ° to 10 °. The angle may, for example, between 1 ° and 5 °. An axis of rotation is to be understood as describing an imaginary line which in the longitudinal direction of the inner tube or the outer tube in each case centrally through the

Passes the inner tube or the outer tube. The intersection of this imaginary axis with a second imaginary line running along the longitudinal direction of the inner tube on the

Outer surface and extends beyond the second end face of the inner tube or along the longitudinal direction of the

Outside tube on the inside and extends beyond the second end face of the outer tube, gives the angle.

Further, the molded article may have a thickness selected from a range of 0.3 mm to 3 mm. The thickness describes the wall thickness of the molding.

The thickness of the shaped body can be selected depending on the applied voltage. Thus, depending on Dimensions of the molding and thus in dependence of

Distance of the inner tube from the outer tube, which represent the electrodes, the ohmic resistance in the molding

be set.

The outer tube, the inner tube and the molded body may together result in a diameter of the functional module selected from a range including 1 mm to 50 mm. The diameter of the functional module comprises one

Inner diameter and an outer diameter. For example, the inner diameter can be 1 mm and a

Outside diameter of 3, 6 mm result, if the wall thickness of the inner tube 0.3 mm, the molding 0.5 mm and the outer tube 0.5 mm. At the same wall thicknesses of the outer tube, the inner tube and the molded body, for example, the outer diameter of the functional module 50 mm and the

Inner diameter 47.4 mm.

The shaped body of the functional module can be a ceramic

Contain material that has the structure Ba _] _- _x -yM _x DyTi _] __ _a _

J ₃ N ₅₁ Mn] ₃ C ^. The structure comprises a perovskite structure. In this case, x includes the range 0 to 0.5, y the

Range 0 to 0.01, a range 0 to 0.01, b range 0 to 0.01, M includes a divalent cation, D a trivalent or tetravalent donor, and N a five or six valent cation. M can be, for example, calcium, strontium or lead, D can be, for example, yttrium or lanthanum,

Examples of N are niobium or antimony. The molded article may include metallic impurities present at a level of less than 10 ppm. The content of

Metallic contamination is so low that the PTC properties of the molding are not affected. This material may have a Curie temperature ranging from -30 ° C to 340 ° C. The material of the molded article can further resist at 25 ° C

which is in a range of 3 Ωcm to 30,000 Ωcm.

It will continue a process for producing a

Function module with the above features

provided. The method comprises the method steps

A) providing an outer tube having a first end side and an inner surface and an inner tube having a first end side and a lateral surface,

B) injection molding or pressing at least one shaped body having a shape which is adapted to the inner surface of the outer tube and to the lateral surface of the inner tube,

C) sintering of the shaped body,

D) arranging the shaped body in the outer tube,

and

E) arranging the inner tube in the shaped body,

F) arranging the first end side of the inner tube and the outer tube on an electrically insulating substrate, wherein the inner tube of the molded body against the inner surface of the

Outer tube presses.

In this case, in step B) of the molding under

Considering the shrinkage of the molding to the

Adjusted inside surface of the outer tube. Depending on the composition of the material for the shaped body, during the sintering in process step C) a shrinkage of the volume of the

Shaped body occur. Thus, in method step B), a shaped body is injection-molded or pressed, which prior to sintering has a shape which corresponds to the inner surface of the outer tube and the lateral surface of the inner tube, to which the shaped body is adapted, is too large and after sintering to the

Inner surface and the lateral surface is adjusted. This ensures a large thermal and electrical contact area between the shaped body and the inner tube and the shaped body and the inner surface of the outer tube.

Furthermore, in method step B), a ceramic starting material is used for the production of the shaped body

which has a ceramic filling material of the structure Ba _x y _x M _x DyTi] __ _a _] ₃ N _a Mn] ₃ θ ₃ and a matrix.

In order to produce the ceramic starting material with less than 10 ppm metallic impurities, it can with

Tools are made, which have a hard coating to prevent abrasion. A hard one

Coating may for example consist of tungsten carbide. All surfaces of the tools with the ceramic

Material can come in contact with the hard

Be coated coating.

In this way, a ceramic filler, which can be converted by sintering into a ceramic PTC material, mixed with a matrix and processed into granules. This granules can for

Further processing injection-molded or pressed to the molding. The matrix in which the ceramic filler material is incorporated and which has a lower melting point than the ceramic material, may have a proportion of less than 20% by mass compared to the ceramic material. The The matrix may comprise a material selected from a group including wax, resins, thermoplastics and

water-soluble polymers. Other additives, like

Antioxidants or plasticizers may also be present.

The method step B) can be the steps

Bl) providing the ceramic starting material,

B2) injection molding or pressing the starting material into a mold, and

B3) Removing the matrix

exhibit .

During sintering in process step C), the ceramic starting material is converted into the material of the shaped body which has a positive temperature coefficient of electrical resistance.

In method steps D) and E), the molded body is fixed between the inner surface of the outer tube and the outer surface of the inner tube by clamping force.

By arranging the inner tube and the outer tube on the electrically insulating substrate in method step F), a frictional connection is produced between the inner tube and the outer tube.

Furthermore, the use of the functional module as a heating module in a heating system or as an overload protection module in a circuit system is provided.

This is a heating module, for example, as

Instantaneous water heater or as a connecting element in one Heating system can be used, provided

efficiently a medium, which is passed through the inner tube and / or around the outer tube, heated. By applying a voltage to the molded body, this heats up due to its positive temperature coefficient of electrical resistance, and this heat to inner tube and the

Leave outside pipe. In this case, the molded body

self-regulating behavior. If the temperature in the molding reaches a critical value, the temperature also increases

Resistance in the molded body, so that less current flows through the molded body. This prevents further heating of the shaped body, whereby no additional electronic regulation of the heating power has to be provided. With this heating module, the medium conducted through the inner tube and / or around the outer tube can be indirectly heated by the shaped body. The heating module may also be used to heat in the inner tube and / or outside of the outer tube

arranged components are used. By using a form-fitting to the inner surface of the outer tube and to the outer surface of the inner tube

arranged moldings, it is possible to improve the efficiency of the heating module compared to conventional heating modules, as a large-area thermal and electrical contact between the molded body and the inner tube and the molded body and the outer tube is provided and thus present a favorable surface volume ratio.

Furthermore, there is no direct contact between the guided from the inner tube and / or to the outer tube, too

heating medium or in the inner tube and / or

outside the outer tube arranged component and the

Moldings. This can be avoided that the molding is corrosively attacked by a medium to be heated or dissolved by the medium, and / or that the material of the shaped body contaminates the medium to be heated or the component to be heated.

For heating arranged outside of the outer tube

Components, the contact surface between the lateral surface of the inner tube and the molded body may be lower than that

Contact surface between the molded body and the inner surface of the outer tube. Furthermore, the thickness of the inner tube may be less than the thickness of the outer tube. Thus, a more outwardly directed heat sink is formed, which causes a high heat dissipation through the outer tube, while less heat is dissipated through the inner tube. Such a heating module can be used for example as a heating cartridge.

Furthermore, an overload protection module can be provided in switching systems in which high currents flow. Due to the above-described shape of the inner tube, the

Shaped body and the outer tube, a large cross section of the molded body is achieved, which leads to low resistances for a small voltage drop across the shaped body. At the same time a small and space-saving design of the module is realized. Thus, a variety of

electronic circuits with high power consumption, where an overload protection is required, with a

reversible, self-regulating overload protection module containing a PTC molded body, be equipped, even if only a small space is available.

Based on the figures and embodiments, the described objects are to be explained in more detail: FIG. 1 shows a schematic side view of a

Cross-section of the functional module, Figure 2 shows a schematic three-dimensional

Front view of the functional module,

FIG. 3 shows a schematic three-dimensional view

Rear view of the function module.

FIG. 1 shows a schematic side view of a cross section of the functional module. Between the outer tube 10 and the inner tube 30 is at least one molded body 20th

arranged. In the figure 1 are two by way of example

However, it is also possible for only one shaped body 20 or even more than two shaped bodies to be arranged one behind the other between the inner tube 30 and the outer tube 10. The shaped body 20 comprises a ceramic having a positive temperature coefficient of electrical resistance and contains a material having the structure Ba _] __ _x _yM _x DyTi _] __ _a _ _b N _a Mn _b O _{3 #} The outer tube 10 is electrically conductively connected to a contact element 15 and the inner tube 30 is provided with a

Contact element 35 electrically connected. The

Contact elements 15 and 35 project separately through an electrically insulating substrate 40 so that they are externally connected to a power source and

simultaneously a short circuit between inner tube 30 and

Outer tube 10 can be avoided. The outer tube 10 and the Inner tube 30 are formed from metals or metal alloys and serve as electrodes for the molded body 20th

The function module can be used, for example, as a heating module

be formed. Then, within the inner tube 30 and / or outside the outer tube 10, a medium is passed, which is indirectly heated by the PTC effect of the molded body 40 upon application of a voltage. The functional module can also be used to enclose a component,

For example, a plug that is to be heated. The heating process starts as soon as the electric

Contacting via the contact elements 15 and 35 a

Current flow is generated in the molded body 20. The inner tube 30 and the outer tube 10 each have a first end face 50 and a second end face 60. For the sake of clarity, in FIGS. 1 to 3 the first end faces of the inner tube and of the outer tube lying on the same side of the functional module are identified by a reference symbol. Likewise, the second end faces is moved.

The inner tube has a lateral surface, which is formed such that the diameter of the inner tube on the first

Similarly, the diameter at the first end face 50 of the inner surface of the outer tube is larger than the diameter formed on the second end face of the inner surface. Furthermore, in the lateral surface of the inner tube 30, a gap 70 is present (not shown here), and the inner tube 30 resiliently

formed. Furthermore, a frictional connection between the inner tube 30 and the outer tube 10 is generated by the electrically insulating substrate 40. This can be the Shaped body 20 are pressed by the inner tube 30 into the outer tube 10. This creates a permanent, non-rigid Klemmkontaktierung that requires no glued joints or additional components, so that eventual

Extensions of different materials can be balanced without causing mechanical stresses in the

Function module occur.

Figure 2 shows a schematic three-dimensional

Front view of the functional module. Here, the gap 70 of the lateral surface of the inner tube 30 can be seen, the to the

Clamping force of the inner tube 30 leads. Furthermore, the

Contact elements 15 and 35 shown, which are exemplified as plates with terminal lugs formed.

FIG. 3 shows the rear view of FIG

Function module shown in three-dimensional schematic view. Here are in the foreground, the contact elements 15 and 35, which are connectable with commercially available flat connectors or crimp terminals. The in the outer tube 10th

located moldings 20 are not visible. At the first end face 50, a part of the inner tube 30 can be seen within the functional module. The embodiments shown in the figures can

can be varied as desired. It's still too

take into account that the invention does not relate to the

Examples limited, but other embodiments not listed here allows. LIST OF REFERENCE NUMBERS

10 outer tube

15 contact element

20 moldings

30 inner tube

35 contact element

40 electrically insulating substrate

50 first end face

60 second end face

70 gap

Claims

claims

1. Function module comprising

- An outer tube (10) having a first end face (50), a second end face (60) and an inner surface,

- An inner tube (30) having a first end face (50), a second end face (60) and a lateral surface which is disposed within the outer tube (10),

- At least one molded body (20), the form-fitting between the inner surface of the outer tube (10) and the

Lateral surface of the inner tube (30) is arranged and has a material with a positive temperature coefficient of electrical resistance,

wherein the first end face (50) of the outer tube (10) and the first end face (50) of the inner tube (30) are arranged on an electrically insulating substrate (40) and the shaped body (20) is arranged between the outer tube (30) and the inner tube ( 10) is fixed by clamping force.

2. Function module according to the preceding claim, wherein the inner tube (30) has a gap (70) in the longitudinal direction of the inner tube (30).

3. Function module according to one of the preceding claims, wherein the inner surface of the outer tube (10) has a

Diameter, and the diameter of the first end face (50) to the second end face (60) tapers.

4. Function module according to one of the preceding claims, wherein the lateral surface of the inner tube (30) has a

5. Function module according to one of the preceding claims, wherein the material of the outer tube (10) and the material of the inner tube (30) comprise metals or metal alloys.

6. Function module according to one of the preceding claims, wherein the inner tube (30) is formed resiliently.

7. Function module according to one of the preceding claims, wherein the inner tube (30) and the outer tube (10)

are positively connected.

8. Function module according to the preceding claim, wherein the outer tube (10) has a first contact element (15) and the inner tube (30) has a second contact element (35) for

Generating an electric current, and the first contact element (15) and the second contact element (35) protrude through the insulating substrate (40).

9. Function module according to one of the preceding claims, wherein the taper of the inner surface and the taper of the outer surface to a rotational axis of the inner tube (30) and a rotational axis of the outer tube (10) have an angle which is selected from a range of 1 ° to 10 °.

10. Function module according to one of the preceding claims, wherein the shaped body (20) has a thickness which is selected from a range of 0.3 mm to 3 mm

includes.

11. Function module according to one of the preceding claims, wherein the shaped body (20) contains a ceramic material having the structure Bai- _x - _y M _x D _y Tii- _a - _b N _a Mn _b θ3, where x = 0 to 0 , 5, y = 0 to 0.01, a = 0 to 0.01, b = 0 to 0.01, M comprises a divalent cation, D comprises a trivalent or tetravalent donor, and N comprises a five or six valent cation ,

12. Functional module according to one of the preceding claims, wherein the shaped body (20) has a Curie temperature, which comprises a range of -30 ⁰ C to 340 ⁰ C.

13. Function module according to one of the preceding claims, wherein the shaped body (20) has a resistance at 25 ° C, which is in a range of 3 Ωcm to 30000 Ωcm.

14. Method for producing a functional module according to

one of claims 1 to 13 with the method steps

A) providing an outer tube (10) having a first end face (50) and an inner surface and a

Inner tube (30) having a first end face (50) and a lateral surface,

B) injection molding or pressing at least one shaped body (20), which has a shape which is applied to the inner surface of the

Outer tube (10) and adapted to the lateral surface of the inner tube (30),

C) sintering of the shaped body (20),

D) arranging the shaped body in the outer tube (10), and

E) arranging the inner tube (30) in the shaped body (20),

F) arranging the first end face (50) of the inner tube (30) and the outer tube (10) on an electric

insulating substrate (40),

wherein the inner tube (30) the molded body (20) against the

Inner surface of the outer tube (10) presses.

15. Use of the functional module according to one of claims 1 to 13 as a heating module in a heating system or as an overload protection module in a circuit system.