DE102022124585A1 - Device for hardening sheet metal components - Google Patents

Abstract

The invention relates to a device for hardening sheet metal components. The device comprises a base plate (01) and a head plate (02), which are connected to one another in a variable distance via guide elements in order to be able to assume an open and a closed state. An adjustable component space (03) remains between the base plate (01) and the head plate (02), into which a component (04) to be hardened can be inserted. A drive is provided to change the distance between the base plate (01) and the top plate (02). Numerous pairs of pressure pieces (06), each consisting of a base plate pressure piece (06a) and a top plate pressure piece (06b), are attached axially opposite one another on the base plate (01) and the top plate (02). At least one pressure piece of each pressure piece pair has an axially displaceable pressure stamp (07), so that the axial distance between the mutually directed ends of the pressure pieces of a pressure piece pair is variable. Numerous coolant nozzles (08) are provided, via which a coolant can be introduced into the component space (03) through an assigned recess (09) in the base plate (01) or in the top plate (02) in order to heat the component (04) to be hardened cool.

Description

The invention relates to a device for hardening sheet metal components. These can be formed or non-formed hardenable sheets, such as those required in vehicle construction, but also in other areas. The device is particularly suitable for hardening formed components, but flat blanks or unformed components can also be hardened with the device.

In order to harden sheet metal components, they are usually heated to over 900 ° C, in particular up to the respective austenitization temperature, and then cooled in a shock manner with the help of a coolant - preferably while maintaining the desired shape.

In the CN 113 249 553 A A method for quenching steel workpieces is described. In a first step, a fluid blowing process is used to apply a cooling medium directly to the surface of the steel workpiece heated to at least the austenitization temperature and to cool it to a temperature of 250-450 ° C within a control time. In the second step, the liquid cooling medium is brought into direct contact with the surface of the steel workpiece so that the workpiece temperature falls below 80°C within a control time of 6 to 20 seconds.

The DD 242 428 A1 describes a device for hardening sheet metal in a quenching bath using press plates to prevent distortion. For this purpose, a flow is generated in a quenching medium by means of displacement devices that are connected to the movable press plates and directed to edge areas of the workpiece to be hardened, whereby an increased quenching effect is to be achieved. The displacement device is arranged on the press plates on the side facing away from the workpiece and consists of an enclosed, circular sector-shaped space. The press plates can be pivoted relative to one another about axes of rotation.

From the DD 201 154 A1 a device for distortion-free hardening of thin sheets is known. The device has an upper and a lower hardening plate and uses a circulating hardening agent. The hardening plates are arranged inclined relative to the horizontal plane, with the hardening agent supply being arranged at the lower end of the hardening plates and the hardening agent drain being arranged at the upper end of the hardening plates. There are groove-like recesses in the hardening plates, in which the hardening agent is guided on both sides of the sheet, the recesses being arranged in such a way that a recess on one hardening plate is opposite a web on the opposite hardening plate.

The DE 890 804 B describes a device and a method for quenching metals, sheets and strips brought to a hardening temperature using quenching liquids or gases. The quenching liquids or gases are divided into individual streams that have different temperatures across the width of the strip or sheet. The strip or sheet brought to hardening temperature is only brought into indirect contact with the quenching liquid or gas in a quenching zone, with the same passing through a thermal barrier before entering the tempering zone.

In the DE 28 56 392 C3 A quenching device for hardening sheets of different widths is described. This includes an upper frame that carries sets of guide and driver rollers as well as a casing around the rollers and that defines a space for the quenching fluid. On both sides of the longitudinal axis of the device, retractable deflection plates are arranged transversely to the direction of travel of the sheets.

Forming and hardening techniques have been used in technology for a long time, although the basic procedure has hardly changed in the last few decades. The starting material is sheet metal, preferably alloyed manganese-boron steels such as 22MnB5, 22MnB8 or others. These steels are characterized, among other things, by the fact that an increase in strength is possible via a heat treatment process. The sheets can be coated without a coating, with a zinc layer or an aluminum-silicon layer to prevent scaling and to provide corrosion protection. The commonly used hot forming can be divided into two groups. In direct hot forming, a blank is heated in an oven, then the heated blank is formed and hardened in a press using cooled tools; Subsequently, scale and oxide layers are removed by sandblasting and finally trimming follows, preferably using laser cutting systems. In indirect hot forming, molded parts are first produced in a press and then heated in an oven; This is followed by mold hardening in a press using cooled tools and finally scale and oxide layers are removed by sandblasting. In both processes, the components are hardened in a press using cooled tools. This makes the tools expensive and the process time-consuming.

Based on the prior art, an object of the invention can be seen as providing an improved device for hardening sheet metal components, which can be easily adapted to various components and dispenses with expensive, cooled pressing or forming tools. Hardening should be possible in a comparatively short time and while maintaining the desired shape of the components, so that post-processing of the components is no longer necessary.

These and other tasks are achieved by a device for hardening sheet metal components according to the appended claim 1.

The device according to the invention is suitable for hardening sheet metal components and is adapted in size, stability and material to the components to be hardened. The device comprises a base plate and a head plate, which are connected to one another via guide elements in a variable distance. The two plates or the device formed by them can thus assume an open and a closed state. In the open state, when using the device, a single or several components to be hardened are placed between the base plate and the head plate in an adjustable component space. The component can already be heated to the austenitization temperature or, in alternative embodiments, can also be heated to this temperature within the device. In the latter case, the device comprises suitable heating elements, for example integrated heating wires.

The device also comprises at least one drive for changing the distance between the base plate and the head plate. The drive can be formed, for example, by integrated electric motors, pneumatic or hydraulic cylinders or by external force generation units.

In addition, numerous pairs of pressure pieces are provided in the device, each of which is formed from a base plate pressure piece and a head plate pressure piece. The two pressure pieces of each pair are mounted axially opposite one another on the base plate or the head plate, so that the mutually directed ends of the pressure pieces are essentially aligned. At least one pressure piece of each pressure piece pair has an axially displaceable pressure stamp, so that the axial distance between the mutually directed ends of the pressure pieces of a pressure piece pair is variable. The pressure pieces are attached to the base or top plate in such a way that the component to be hardened is positioned between the mutually facing ends of the pressure pieces when it is inserted into the device. The individual pairs of pressure pieces are adapted to the shape of the component to be hardened, so that the pressure stamps facing each other rest on the component in order to keep it in shape during the further hardening process. The pressure pieces are adapted to the shape of the respective component, in particular by adjusting the respective distance between the ends of the pressure pieces belonging to a pair of pressure pieces and shifting them to the desired level.

The device can therefore be easily and quickly adapted to different components by adjusting the pressure piece pairs. In this way, the device can be configured for hardening different components and thus replaces expensive cooled pressing tools that can only be used for a specific component.

The device also has numerous coolant nozzles, with each coolant nozzle allowing coolant to be introduced into the component space through an assigned recess either in the base plate or in the top plate. This serves to cool the component to be hardened that is inserted into the component space. The base and head plates therefore have numerous recesses to enable the coolant to be supplied. The coolant nozzles are connected to a coolant system and can be supplied with coolant together or alternatively individually or in groups. The coolant nozzles are preferably positioned in such a way that coolant can be applied via them to the entire surface of the component to be hardened. This ensures that all areas of the component can be cooled simultaneously and evenly during hardening.

A significant advantage of the device is that it enables sheet metal parts to be hardened outside of cooled pressing tools (hot forming tools). This makes the hardening process significantly cheaper.

According to a preferred embodiment, a water-air mist, water, an emulsion or another medium suitable for hardening the components is used as the coolant. Particularly preferably, the temperature and volume of the coolant delivered to the component via the coolant nozzles can be adjusted so that the component cools from the austenitization temperature (starting temperature) to a target temperature of approximately 150 ° C within a period of less than 20 seconds, preferably less than 15 seconds, in particular within 12 seconds or even less.

Preferably, the coolant nozzles and the recesses are on or in the base plate and the head plate is arranged in such a way that the component to be hardened can be wetted by the coolant over its entire surface from at least one side. Particularly preferably, there are numerous recesses in both the base plate and the head plate through which the coolant nozzles spray the coolant so that the component is wetted with the coolant from both sides. The coolant nozzles can preferably be attached to the base plate or head plate via spacers.

According to a further developed embodiment, both pressure pieces of each pair of pressure pieces each have an axially displaceable pressure stamp. In this way, the axial distance of the pressure stamps from both the base plate and the top plate can be changed, which means that they can be very individually adapted to the shape of the component to be hardened. The component to be hardened is thus clamped on both sides between the pressure stamps, so that the specified shape is kept stable at many bearing points, even if material tensions occur during the hardening process.

The axially displaceable pressure piece stamps are preferably adjustable manually or independently of one another via pressure piece drives. The pressure piece drives can, for example, be activated electrically, hydraulically or mechanically. In particular, the pressure piece stamps can be moved axially via a thread or by means of replaceable spacers. The axially displaceable pressure piece stamps are particularly preferably designed in a conical shape, preferably consist of a ceramic material or have a ceramic coating in order to show low adhesion to the surface of the component to be hardened. In alternative embodiments, the pressure piece stamps can also be made of steel or composite materials.

A preferred embodiment is characterized in that the drive for changing the distance between the base plate and the head plate is a mechanical, pneumatic, hydraulic or electric drive. In general, transmission gears can be used or the drive is coupled to the plates without a gear.

Particularly preferably, the drive and the number of pairs of pressure pieces are coordinated with one another in such a way that, in the closed state, a contact force of at least 10 N acts on the component to be hardened on each pressure piece.

• 1 eine vereinfachte Schnittansicht einer Ausführungsform einer erfindungsgemäßen Vorrichtung zum Härten von Blechbauteilen;
• 2 eine Detailzeichnung der Vorrichtung gemäß 1;
• 3 eine Perspektivansicht der Vorrichtung gemäß 1.

Further advantages and details of the invention result from the following description of a preferred embodiment, with reference to the drawing. Show it:

• 1 a simplified sectional view of an embodiment of a device according to the invention for hardening sheet metal components;
• 2 a detailed drawing of the device according to 1 ;
• 3 a perspective view of the device according to 1 .

1 and 2 show a device according to the invention for hardening sheet metal components, each in a side sectional view, wherein 2 shows a section of the device enlarged. The device comprises a base plate 01 and a head plate 02, which are connected to one another via guide elements (not shown) with a variable distance. By changing the distance, the plates can be moved from an open to a closed state. An adjustable component space 03 thus remains between the base plate 01 and the head plate 02, into which a component 04 to be hardened can be inserted. A drive is provided for changing the distance between the base plate 01 and the head plate 02 (not shown).

Numerous pairs of pressure pieces 06 are positioned between the base plate 01 and the top plate 02, each consisting of a base plate pressure piece 06a and a head plate pressure piece 06b. The base plate pressure piece 06a is attached to the base plate 01. The head plate pressure piece 06b lies axially aligned opposite the base plate pressure piece 06a and is attached to the head plate 02. In the illustrated embodiment, both pressure pieces of the pressure piece pair 06 each have an axially displaceable pressure stamp 07 at their mutually directed ends, so that the axial distance between the pressure stamps is variable. The distance between the pressure stamps is set depending on the thickness of the component 04 at the respective location. The position of the component gap remaining between the opposing pressure stamps in relation to the base and top plates is adapted to the shape of the component.

Furthermore, the device has numerous coolant nozzles 08 through which a coolant can be dispensed. The coolant nozzles 08 are each attached to the base plate 01 or the top plate 02 at an axial distance from the plate, with adjacent coolant nozzles 08 having a distance from one another that is determined so that the emerging coolant essentially covers all surface areas of the component 04 to be hardened can reach. So that the coolant can be applied to the component 04, there are recesses 09 in the base plate 01 and attached in the head plate 02, the coolant nozzles 08 each being assigned to such a recess 09.

Before the actual hardening process, the component 04 that is later to be hardened is first conventionally cold formed in a press. After the forming process, the component 04 is heated, for example, in an oven to over 900 ° C. The components can also be heated using other methods or even within the device according to the invention. Once the heating process is complete, the component is placed in the device. For this purpose, the base and head plates are in the open state. The pressure piece pairs 06 were previously adapted to the shape of the component 04 to be hardened. The deposited component 04 is now clamped in the device by transferring the base and head plates into the closed state, i.e. H. be moved towards each other. In the closed state, the pressure stamps 07 rest on the component 04 at numerous positions. Within a few seconds, the component 04 is then evenly distributed by supplying the coolant to e.g. B. cooled down to 150 ° C. This increases the hardness/strength of the component.

Due to the different stress distributions in the component, the component would warp if it cooled freely. The material stresses that occur during cooling are absorbed and compensated for by the pairs of pressure pieces. According to a further developed embodiment, the coolant nozzles 08 can be opened at a different time, so that a controlled application of coolant to the component via the coolant nozzles 08 is possible. This can also contribute to reducing or compensating for the material stresses in component 04.

3 shows the device again in a perspective view. It can be seen that for flat components 04, numerous pairs of pressure pieces 06 are attached to the base plate 01 or top plate 02 and numerous coolant nozzles 08 are provided.

Rust- and acid-resistant materials are particularly suitable as materials for all components of the device in order to keep wear and tear to a minimum. A suitable coating that prevents corrosion of the base material can also be used. A ceramic connection is preferred for the preferably conical pressure stamps 07, as this results in less heat dissipation from the component 04 to be hardened. The contact surface of the printing stamp must be made as small as possible (at certain points). For each pressure piece 06, a preferred contact force of at least 10 N can be expected. The pressure pieces are designed to be axially adjustable in the direction of the component. This can be done through a thread or by using spacers. The pressure pieces 06a, 06b preferably have a length of approximately 40 mm, so that the component surface can still be easily reached by the coolant. The central distance between adjacent pressure pieces is preferably not more than 50 mm. This distance from the edge of the component is preferably chosen to be no greater than 5 mm. So that the coolant can reach the component to be hardened unhindered, the remaining webs between adjacent recesses in the base and top plates are preferably not wider than 15 mm. The pressure pieces 06 are attached to these webs.

In order to ensure that the device closes precisely, robust guide elements are selected. These are preferably designed to be wear-resistant and corrosion-resistant. The device can be closed and opened, for example, by driving the head plate 02 on one side if the base plate 01 is designed to be fixed to the frame. Reverse or double-sided drive can also take place.

The size of the device depends on the component size and the number of components to be hardened at the same time. Scaling the device size is therefore easily possible.

Reference symbols

01

Base plate

02

Headstock

03

Component space

04

component to be hardened

05

-

06

Pair of pressure pieces

06a

Base plate pressure piece

06b

Head plate pressure piece

07

Print stamp

08

coolant nozzle

09

recess

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was 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

• CN 113249553 A [0003]
• DD 242428 A1 [0004]
• DD 201154 A1 [0005]
• DE 890804 B [0006]
• DE 2856392 C3 [0007]

Claims (10)

Device for hardening sheet metal components, comprising: - a base plate (01) and a head plate (02), which are connected to one another via guide elements at a variable distance in order to be able to assume an open and a closed state, whereby an adjustable component space (03) remains between the base plate (01) and the head plate (02), into which a component (04) to be hardened can be inserted; - a drive for changing the distance between the base plate (01) and the head plate (02); - numerous pressure piece pairs (06), each consisting of a base plate pressure piece (06a) and a head plate pressure piece (06b), which are attached axially opposite one another on the base plate (01) or the head plate (02), whereby at least one pressure piece of each pressure piece pair has an axially displaceable pressure stamp (07), so that the axial distance between the mutually facing ends of the pressure pieces of a pressure piece pair is variable; - numerous coolant nozzles (08), wherein a coolant can be introduced via each coolant nozzle through an associated recess (09) either in the base plate (01) or in the head plate (02) into the component space (03) in order to cool the component (04) to be hardened which is inserted there. Device according to Claim 1 , characterized in that the coolant nozzles (08) and the recesses (09) in the base plate (01) and the top plate (02) are arranged in such a way that the component (04) to be hardened is penetrated over its entire surface at least from one side Coolant is wettable. Device according to Claim 1 or 2 , characterized in that both pressure pieces of each pressure piece pair (06) each have an axially displaceable pressure stamp (07). Device according to one of the Claims 1 until 3 , characterized in that the axially displaceable pressure piece stamps (07) can be adjusted manually or via pressure piece drives. Device according to Claim 4 , characterized in that the pressure piece stamps (07) are axially displaceable via a thread or replaceable spacers. Device according to one of the Claims 1 until 5 , characterized in that the axially displaceable pressure piece stamps (07) are conical and consist of a ceramic material or have a ceramic coating. Device according to one of the Claims 1 until 6 , characterized in that the drive for changing the distance between the base plate (01) and the top plate (02) is a mechanical, pneumatic, hydraulic or electric drive. Device according to one of the Claims 1 until 7 , characterized in that the drive and the number of pressure piece pairs (06) are coordinated with one another in order to exert a contact force of at least 10 N on the component (04) to be hardened on each pressure piece in the closed state. Device according to one of the Claims 1 until 8th , characterized in that the coolant nozzles (08) are dimensioned to cool the component (04) to be hardened from an initial temperature of 900 ° C to a target temperature of a maximum of 150 ° C within a maximum of 15 seconds. Device according to one of the Claims 1 until 9 , characterized in that it further contains heating elements to heat the component to be hardened.

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