DE102018202326A1 - Plastic molding and method for producing the plastic molding - Google Patents

Abstract

Electronic components are placed in housings for mechanical protection and / or EMC shielding. A plastic molded part 1 for housing an electronic component 2 is proposed, with a reinforcing component 3 and a plastic component 4, wherein the reinforcing component 3 is at least partially embedded in the plastic component 4, wherein the reinforcing component 3 is designed as a carbon fiber-based knitwear.

Description

State of the art

The invention relates to a plastic molding for housing of electronic components, with a reinforcing component and a plastic component, wherein the reinforcing component is at least partially embedded in the plastic component.

Electrical components are often arranged in housings. Such housings are preferably made of metallic materials. Advantages of such metallic housing are the high mechanical strength, stiffness and thermal conductivity to dissipate heat loss from the inside of the housing well and effectively to the outside. Furthermore, such metallic housings are good shields for electromagnetic radiation (EMC). Housing made of plastics are hardly known here.

The publication DE 10 2013 208 605 A1 , which is probably the closest prior art, describes a process for the production of plastic moldings. The method provides that the molding is molded by injection molding with a mixture of a polymer and thermally conductive fillers, wherein during molding by injection molding based on the surface geometry of the cavity of the injection molding tool, the filler particles are oriented transversely to the molding plane. These moldings are characterized by a good thermal conductivity transverse to the mold part level.

Disclosure of the invention

It is proposed a plastic molding for housing of electronic components with the features of claim 1. Furthermore, a method for producing the plastic molding with the features of claim 14 is proposed. Preferred and / or advantageous embodiments will become apparent from the subclaims, the following description and the accompanying figures.

It is proposed a plastic molding for housing electronic components. The plastic molded part is formed for example as an organic sheet. In particular, the plastic molding may be formed as a semi-finished product. The plastic molding is preferably formed insulating and can form a contact protection for the electronic component. The electronic component is in particular form-fitting manner in the plastic molded part can be arranged. The plastic molding in particular forms a housing for the electronic component. The electronic component is for example an electric drive, a motor, a battery or power electronics. The plastic molding in particular forms a fiber composite material.

The plastic molded part has a reinforcing component and a plastic component. The plastic component forms in particular a plastic matrix. The plastic component itself can be a multi-component mixture. In particular, the plastic component is formed as a resin or a plastic. Further, the plastic component may be an injection molded plastic or a plastic for extrusion. The plastic component is constructed, for example, of a thermoplastic or of a duroplastic. Polypropylene, polyethylene, polyurethane, polystyrene, liquid crystal polymer, polycarbonate, polyester, polyphenylene sulfide, polyamide, WMC and epoxy resin are particularly suitable as the plastic component.

The reinforcing component is at least partially embedded or arranged in the plastic component. Preferably, the reinforcing component is completely disposed in the plastic component and / or completely surrounded by the plastic component. For example, the reinforcing component is encapsulated with the plastic component. Alternatively and / or additionally, the plastic component is injected into the reinforcing component. In particular, the reinforcing component is impregnated with the plastic component. In particular, the reinforcing component forms a planar component, wherein the reinforcing component can also form a three-dimensional shape, for example a tubular or cylindrical shape. The planar reinforcing component is then sprayed or poured out, for example, with the plastic component.

According to the invention, the reinforcing component is designed as a carbon fiber-based knitwear. The reinforcing component is formed, for example, reticulated. The reinforcing component is in particular flat and preferably rollable and / or from the roll. The knitwear may be a fabric, a scrim and / or a textile. The reinforcing component is for improving mechanical strength, improving thermal conductivity and / or EMC shielding. The reinforcing component and / or the knitted fabric has a thermal conductivity and / or an electrical conductivity. The carbon fibers are especially inorganic carbon fibers. The carbon fibers are preferably constructed of elemental carbon and / or elemental carbon modifications.

It is a consideration of the invention to provide a plastic molding which is suitable for housing of electronic components and can be mechanically stable, thermally resistant and / or conductive and / or EMC shielding. Further, as base materials, rolls of material and / or readily available plastic blends may be used. In order to produce the plastic molding in particular cheap tools can be used, for example, aluminum die casting tools or simple molds made of wood, ceramic, stone or temperature-resistant plastic. The plastic molded part can form a contact protection and is in particular electrically insulating. When using the reinforcing component, in particular a puncture-proof plastic molded part can be provided. It is particularly preferred that the carbon fibers comprise graphene fibers and / or carbon nanotubes. In particular, the carbon fibers may also be formed as graphene fibers and / or carbon nanotubes. Carbon nanotubes are also referred to as carbon nanotubes. In particular, the carbon fibers have a density of at least 1.35 grams per cubic centimeter and less than 1.65 grams per cubic centimeter. The electrical conductivity of the carbon fibers is, in particular, greater than ten Siemens per micron, and preferably greater than forty Siemens per micron. The carbon fibers preferably have a temperature coefficient with respect to the electrical resistance, wherein the temperature coefficient is, for example, less than 1.6 × 10 ^-3 per Kelvin. The thermal conductivity, in particular the axial thermal conductivity of the carbon fibers is preferably greater than 600 watts per meter x Kelvin and optionally greater than 800 watts per meter x Kelvin. In particular, the carbon fibers have a fiber length and a fiber diameter, the fiber length preferably being greater than 100 micrometers, and more particularly greater than one centimeter. The fiber diameter is for example in the range between one and fifty nanometers. The carbon fibers may also comprise a plurality of carbon nanotubes and be in the form of a tube bundle, the length of such carbon fibers preferably being between ten centimeters and one meter.

Optionally, the knitwear is formed as a knit. In particular, the knitwear may also be formed as a woven fabric, a knitted fabric or a scrim. The knitwear is in particular a flat knitwear and forms, for example, a textile. In particular, the reinforcing component may also be formed as a nonwoven and / or comprise a nonwoven. The knitwear is identifiable by a thread density, the thread density indicating the threads per centimeter. The thread density for the knitwear may be constant throughout the range or may change as the knitwear proceeds.

Particularly preferably, the knitwear has at least one excellent fabric direction for strength control. The fabric direction can be constant and / or uniform over the entire area of the knitwear, alternatively the fabric direction can be changed over the area of the knitwear. For example, the tissue direction changes on a macroscopic scale, for example, over several centimeters, especially over five centimeters. The fabric direction can change continuously or discontinuously. In particular, the strength can be controlled by means of the fabric direction and / or the thread density. Areas with high thread density are stronger than areas with low thread density.

It is particularly preferred that the plastic molding has at least two molding sections. Furthermore, it is possible that the plastic molded part has a plurality, in particular more than five, molded part sections. The molded part sections here are in particular macroscopic sections, for example with several square centimeters of surface area. For example, a molding portion has at least an area of one square centimeter, and more preferably more than ten square centimeters. In particular, the molding sections are spaced apart, alternatively, the molding sections may merge into one another.

The molded part sections have different mechanical and / or physical properties. For example, the shaped part sections have different densities, strengths, electrical and / or thermal conductivities. The reinforcement components contained in the molding sections may have different reinforcement component properties for two different molding sections. For example, the thread density, the fabric direction or the type of fiber is different in two different molding sections. The transition of the mechanical and / or physical properties from one molding section to the next molding section is preferably continuous. Alternatively, the transition of the molding sections may be discontinuous and / or erratic.

Optionally, the molded part sections for strength control on knitted fabric of different structure. For example, the structure of the knitted fabric is the knitting pattern, the weave, the fabric direction and / or the thread density. For two molding sections of the same plastic molding the knitted fabric is constructed with a different structure. By using different knitted fabric in the molding sections, the strength and / or other mechanical Properties of the plastic molded part are controlled so that, for example, the strength and / or a concern of the plastic molded part can be controlled and / or optimized to the electronic component.

An embodiment of the invention provides that the molded part sections for strength control have knitwear of different extensibility. In particular, the molded part sections may have different plastic components, wherein the plastic components may have a different composition, elasticity, flexibility and / or plasticizer content. By changing the extensibility of the molded part sections, a conformal contact of the plastic molded part to the electronic component is possible.

Optionally, it is provided that the knitwear has drawstrings for contracting the knitwear. The drawstrings can be woven over the entire range of knitwear or only in sections in certain sections of the knitwear. By pulling on the pulling threads, the knitwear and / or the plastic molding pulls together, in particular in a predetermined and / or predeterminable manner. By weaving in the drawstrings, the subsequent structure of the plastic molded part in the contracted state of the knitwear is controllable and / or adjustable.

It is particularly preferred that the knitwear has at least one sensor fiber for measuring a physical quantity. In particular, the knitwear may have a plurality of sensor fibers. The sensor fibers are in particular woven into the knitwear. The sensor fiber is designed for example for pressure measurement, temperature measurement, strain measurement and / or measurement of an electromagnetic field. It is particularly preferred that the sensor fiber can measure local properties in the plastic molded part. Alternatively, the sensor fiber is designed for the global measurement of a property in the plastic molding.

Optionally, the sensor fiber is designed for temperature measurement. For example, the sensor fiber has a temperature-dependent electrical resistance for this purpose. The sensor fiber is electrically contacted, for example, so as to measure the temperature. The sensor fiber may be, for example, a thermistor or a PTC thermistor. Particularly preferably, the sensor fiber is designed as a platinum measuring resistor.

An embodiment of the invention provides that the knitted fabric has electrically conductive fibers. In particular, the carbon fibers are electrically conductive. The carbon fibers and / or the electrically conductive fibers are electrically contacted. In particular, the knit fabric forms an electrically conductive mesh. The knit fabric with the conductive fibers is designed for EMC shielding.

Optionally, the knitted fabric has electrically conductive fibers for heating the plastic molded part. The knitted fabric can form heating braid for the plastic molding, which can heat the plastic molding by electricity. For this purpose, the knitwear has, for example, a fiber made of a heating conductor alloy. In particular, the heating conductor alloy is Nichrome, Manganin, Nickelin, Ferrochronin, Sichromal or Kanthal.

It is particularly preferred that the reinforcing component is encapsulated by the plastic component. For example, for this purpose, the reinforcing component is adapted to its subsequent use and / or shaped and then injected with the plastic component and / or overmoulded. The plastic molded part can thus be produced in an injection molding process and / or extruder process. Alternatively, the reinforcing component may be filled with a resin and / or be poured with a plastic. Furthermore, by impregnating the reinforcing component with a liquid plastic for the production of the plastic molding serve.

It is particularly preferred that the plastic molded part has cooling channels. The cooling channels are in particular embedded in the plastic component and / or are formed by the plastic component. The cooling channels can be produced in particular in a multi-layer casting process. For example, for this purpose, the knit fabric is repeatedly soaked with plastic and / or molded, in which case cooling channels are einarbeitbar. The cooling channels can also be prefabricated by inserts, for example made of plastic or metal, introduced into the plastic component. Furthermore, carrier structures, in particular as inserts, can be introduced into the plastic component.

Another object of the invention is a method for producing the plastic moldings. In particular, the method is used to produce the plastic moldings as previously described. According to the method, a reinforcing component is at least partially embedded in a plastic component. The reinforcing component forms a knit fabric. For this purpose, the reinforcing component is soaked, for example, with the plastic component, for example a plastic or a resin, and cured. The reinforcing component can also be poured out with the plastic component. Especially it is preferred that the reinforcing component is extrusion-coated with the plastic component, for example in an injection molding process step. In particular, the plastic component can also be injected into the reinforcing component. The casting and / or embedding step may in particular also be preceded by a weaving, knitting or knitting step, the knitted fabric being produced in this step. The knitwear can be made to fit between the weaving, knitting or knitting step and the pouring and / or embedding step. After the knitwear is brought into shape, for example a tube, the knitted fabric brought into shape is overmolded with the plastic component and / or embedded in the plastic component.

An embodiment of the method provides, in particular, that before the embedding of the reinforcing component in the plastic component, the knitted fabric is brought into shape, is contracted and / or contoursah applied to the electronic component. For example, the knitwear includes drawstrings, wherein by pulling on the drawstrings the knitwear is nestled and / or applied to the electronic component. After donning, nestling or shaping, the knitwear, ie the reinforcing component, is overmolded, soaked and / or embedded in the plastic component.

• 1 ein Kunststoffformteil als ein erstes Ausführungsbeispiels;
• 2a, 2b und 2c Ablauf eines Verfahrens zur Herstellung des Kunststoffformteils;
• 3a und 3b eine Verstärkungskomponenten für ein Kunststoffformteil mit mehreren Formteilabschnitten;
• 4a und 4b eine Verstärkungskomponente mit Ziehfäden.

Further advantages and effects will be apparent from the attached figures and their description. Showing:

• 1 a plastic molding as a first embodiment;
• 2a . 2 B and 2c Sequence of a method for producing the plastic molding;
• 3a and 3b a reinforcing component for a plastic molding having a plurality of molding portions;
• 4a and 4b a reinforcing component with pulling threads.

1 shows a plastic molding 1 and an electronic component 2 , The electronic component 2 is for example an electronic board. The plastic molding 1 forms a housing for the electronic component 2 , The plastic molding 1 surrounds the electronic component positively and in particular captive. In particular, the plastic molding surrounds 1 the electronic component 2 a sleeve.

The plastic molding 1 has a reinforcing component 3 and a plastic component 4 on. In particular, the reinforcing component 3 in the plastic component 4 completely arranged, with the plastic component 4 For example, a matrix for the gain component 3 forms. The gain component 3 is completely from the plastic component 4 surrounded and / or embedded in this.

The plastic component 4 is made of a plastic. Plastic component 4 For example, is formed by a thermoset, alternatively, the plastic component 4 be formed by an elastomer. The plastic component 4 is in particular electrically insulating. The plastic component 4 In particular, it has a density less than two grams per cubic centimeter. The tensile strength of the plastic component is preferably in the range of greater than eighty megapascals. For example, the plastic component is formed by an epoxy resin.

The gain component 3 is made of a knitted fabric. The knitwear is made of a carbon fiber. The knitwear is for example a knitted fabric, a woven fabric or a braid. The carbon fiber is preferably a graphene fiber and specifically a carbon nanotube, also called carbon nanotube or carbon nanotube. The carbon fiber may also be formed from a bundle of carbon nanotubes. The knit fabric has a density between 1.4 grams per cubic centimeter and two grams per cubic centimeter. Further, the knitted fabric and the reinforcing component 3 electrically conductive and has an electrical conductivity of greater than thirty Siemens per micrometer. In particular, the knitwear is also thermally conductive with a thermal conductivity greater than 600 watts per meter x Kelvin.

The knitted fabric and the reinforcing component 3 surrounds the electronic component 2 also positive and in particular captive. The plastic of the plastic component 4 is preferably also in the knit fabric of the reinforcing component 3 arranged. For example, the reinforcing component 3 with the plastic of the plastic component 4 soaked, sprayed and / or injected.

2a to 2c show schematically the sequence of a method for producing the plastic molding 1 ,

2a shows an electronic component 2 that is in the reinforcing component 3 was plugged. The gain component 3 This forms a textile. The textile is tubular and has two openings. The electronic component 2 is formed by an electric motor. The electric motor is in the tubular reinforcing component 3 inserted, wherein the reinforcing component loosely around the electronic component 2 lies.

2 B shows a method step in which the gain component 3 in the axial direction 5 is stretched, wherein the reinforcing component 3 then in the radial direction 6 contracts. By stretching in the axial direction 5 becomes the gain component 3 close to the electronic component 2 created. The application can also be considered a constriction in the radial direction 6 be understood. After applying the reinforcing component 3 to the electronic component 2 follows the encapsulation and / or pouring with the plastic component 4 , This is the gain component 3 in the plastic component 4 and / or with the plastic of the plastic component 4 soaked. It is also possible to encapsulate and inject the plastic component 4 and / or the plastic of the plastic component 4 in the reinforcing component 3 ,

After curing and / or polymerizing the plastic of the plastic component 4 is the plastic molding 1 as in 2c shown available. The plastic component closes the reinforcing component 3 from the environment. The gain component 3 is contacting the electronic component 2 arranged. The plastic molding 1 surrounds the electronic component 2 tubular and sleeve-shaped. The plastic molding 1 indicates the mechanical and chemical properties of the plastic component 4 on, for example, electrically insulating, lightweight and flexible. Furthermore, the plastic molding has 1 also the mechanical and / or physical properties of the reinforcing component 3 on, for example, an EMC shield by the electrically conductive graphene fibers.

3a shows a reinforcing component 3 for a plastic molding 1 with three molding sections 7a . 7b and 7c , The molding sections 7a and 7c have the same and / or similar physical and mechanical properties. The molding section 7b differs in the mechanical and / or physical properties of the molding sections 7a and 7c , The gain component 3 in the molding sections 7a and 7c has a high rigidity and are hardly stretchable. The reinforcing component 3 in the molding section 7b however, it has increased flexibility, elasticity and elasticity.

3b shows how the electronic component 2 , here again an electric motor, into the tubular reinforcing component 3 was plugged. The reinforcing component nestles here 3 of the molding section 7b good and positive fit to the electronic component 2 on. The reinforcing component in the region of the molded part sections 7a and 7c however, hardly fits the geometry of the electronic component 2 because it is not stretchy and flexible in the sections. After inserting the electronic component 2 in the reinforcing component 3 with the three molding sections 7a . 7b and 7c , becomes the gain component 3 with the plastic component 4 overmoulded and the plastic molding 1 generated. The plastic molding 1 thus also has three molding sections 7a . 7b . 7c on, wherein in these molding sections 7a . 7b and 7c the gain component 3 has different mechanical properties.

The 4a shows an embodiment of the gain component 3 in which the reinforcing component 3 two pulling threads 8th having. The pulling threads are 8 at an open end of the reinforcing component 3 arranged. In the reinforcement component 3 is already an electronic component 2 arranged. After arranging the electronic component 2 can on the pulling threads 8th to be pulled.

In 4b is shown by pulling on the pulling threads 8th the open end closes, leaving the reinforcing component 3 the electronic component 2 now completely surrounds at an originally open end. After closing the open end, the reinforcing component 3 with the plastic component 4 be sprayed and so the plastic molding 1 to be obtained.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102013208605 A1 [0003]

Claims (15)

Plastic molding (1) for housing an electronic component (2), with a reinforcing component (3) and a plastic component (4), wherein the reinforcing component (3) is at least partially embedded in the plastic component (4), characterized in that the reinforcing component (3 ) is formed as a carbon fiber-based knit fabric. Plastic molding (1) after Claim 1 , characterized in that the carbon fibers comprise graphene fibers and / or carbon nanotubes. Plastic molding (1) after Claim 1 or 2 , characterized in that the knitwear is formed as a knit. Plastic molding (1) according to one of the preceding claims, characterized in that the knitted fabric has at least one excellent fabric direction for strength control. Plastic molding (1) according to one of the preceding claims, characterized by at least two molding sections (7a, 7b, 7c), wherein the molding sections (7a, 7b, 7c) have different mechanical and / or physical properties. Plastic molding (1) after Claim 5 , characterized in that the shaped part sections (7a, 7b, 7c) for strength control have knitwear of different structure. Plastic molding (1) after Claim 5 or 6 , characterized in that the molded part sections (7a, 7b, 7c) for strength control have knitwear of different extensibility. Plastic molding (1) according to one of the preceding claims, characterized in that the knitted fabric has draw threads (8) for contraction of the knitwear. Plastic molding (1) according to one of the preceding claims, characterized in that the knitted fabric has at least one sensor fiber for measuring a physical quantity. Plastic molding (1) after Claim 9 , characterized in that the sensor fiber for temperature measurement has a temperature-dependent electrical resistance. Plastic molding (1) according to one of the preceding claims, characterized in that the knitted fabric comprises electrically conductive fibers, wherein the electrically conductive fibers are electrically contacted for EMC shielding. Plastic molding (1) according to one of the preceding claims, characterized in that the knitted fabric has electrically conductive fibers for heating the plastic molded part (1). Plastic molding (1) according to one of the preceding claims, characterized by cooling channels, wherein the cooling channels are embedded and / or formed by the plastic component. Method for producing a plastic molded part (1), in particular a plastic molded part (1) according to one of the preceding claims, wherein a knit fabric based on carbon fibers is embedded as a reinforcing component (3) in a plastic component (4). Method according to Claim 14 , characterized in that before the embedding of the reinforcing component (3) in the plastic component (4) the reinforcing component (3) is applied to the electronic component (2) and / or the reinforcing component (3) is pulled together.

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