DE102017216278A1 - Tool and process for hydroforming with reduced cycle time - Google Patents

Abstract

The invention relates to a tool (100) for the hydroforming metallic hollow body (200) by means of active medium, with an upper tool (120) and a lower tool (110), which are formed with a cavity (130) for receiving a hollow body (200) the lower tool (110) has an inlet channel (180) for prefilling a hollow body (200) with active medium inserted into the cavity (130), which opens into the cavity (130) in front of an opening (210) of the inserted hollow body (200) the opening (210) of the inserted hollow body (200) is aligned. The invention further relates to a method to be carried out with this tool (100) for producing a component by hydroforming.

Description

The invention relates to a tool for hydroforming metallic hollow body according to the preamble of claim 1. The invention further relates to a method for producing a component by hydroforming.

In hydroforming (IHU) is the reshaped hollow body or the reshaped hollow workpiece, for. As a tube, inserted into the cavity of a forming tool (hydroforming tool), filled with a working medium (fluid) and reshaped by applying a high internal pressure. During the forming process, the openings of the hollow body are sealed by sealing stamp.

The cycle time in the hydroforming is significantly determined by the filling time for filling the reshaped hollow body with the active medium. This process is also called prefilling.

The DE 196 28 688 C1 describes a rapid filling device for the filling of the forming liquid into the blank before the beginning of the forming work. From the 1 If one removes that to a Umformflüssigkeitsbehälter ( 11 ) a fast filling channel ( 12 ) of large nominal size, which is located on one side of the mold space ( 5 ) via an inlet bore ( 13 ) into a section of the matrix system ( 4 ) between inserted blank ( R ) and at rest Umformstempel located ( 7 ). The inlet bore ( 13 ) is substantially vertical.

The prior art is in addition to the DE 103 43 868 B3 , which describes a fast filling device, which has a displaceable filling attachment with a filling bore.

With the invention, a further reduction of the cycle time during hydroforming is to be achieved.

This is achieved with a tool according to the invention according to the patent claim 1 and with a method according to the invention according to the independent claim. Further developments and embodiments of the invention will become apparent for both subject invention from the dependent claims, the following description of the invention and the drawings.

The tool according to the invention or hydroforming tool comprises an upper tool (upper mold half) and a lower tool (lower mold half) which are formed with (at least) one cavity or a mold space for receiving a hollow body to be formed. Self-explanatory, the tool can be opened and closed by vertically moving the upper tool. In the lower tool is (at least) an inlet channel for pre-filling or rapid filling of a hollow body inserted into the cavity with active medium, wherein the inlet channel opens into an opening of the inserted hollow body into the cavity and is aligned with this opening of the inserted hollow body.

The inlet channel is formed at least at its cavity-side mouth so that the pre-filling through the inlet channel flowing active medium directly, d. H. without deflection, can flow into the opening of the hollow body inserted in the cavity, which is thereby filled or flooded. As a result, prefilling can already be started before the tool is closed. In addition, the tool closing speed can be increased. Furthermore, the sealing punches can be positioned in their rest position closer to the hollow body to be formed. Cycle time reductions in the range of several seconds are possible, which brings considerable advantages in particular in mass production. Furthermore, the formation of air bubbles in the active medium is significantly reduced.

Preferably, the inlet channel is formed as a straight bore, which extends quasi obliquely through the lower tool. The bore axis of this bore or its extension points into the opening of the hollow body inserted in the cavity, so that the flow axis of the flowing through the inlet channel and the inlet bore active medium is directed directly into the interior of the hollow body.

The inlet channel may be formed as a slot hole. This means that the inlet channel is formed as a hole with a slot cross-section. This bore cross-section favors a high volume flow at low pressure (low pressure), allowing for rapid prefilling with little air bubble formation. Preferably, the slot geometry is adapted to the opening geometry of the hollow body, in particular such that there is the greatest possible coverage along the flow axis.

Preferably, the mouth of the inlet channel is not more than 5 mm from the opening or the opening edge of the inserted hollow body spaced. Particularly preferred is no distance between the mouth of the inlet channel and the opening or the opening edge of the inserted hollow body is provided.

The tool according to the invention may further comprise at least one movable sealing punch have, with which the opening of the inserted hollow body is sealable, wherein the tool is formed so that the sealing plunger closes the mouth of the inlet channel when approaching the opening.

The inlet channel may at its end facing away from the mouth end with a connection, for. B. a hose or line connection, be formed, via which the active medium can be supplied for the purpose of pre-filling, z. B. by means of a filling pump.

The lower tool may have means for holding or fixing the inserted hollow body in order to prevent the slipping of the hollow body during priming, as long as the tool is not yet closed. This can z. B. magnetic holder or vacuum suction.

• - Einlegen des umzuformenden Hohlkörpers in das Unterwerkzeug (bei geöffnetem Werkzeug), derart, dass sich eine Öffnung des Hohlkörpers neben der Mündung des Einlaufkanals in die Kavität befindet;
• - Vorfüllen (Fluten) des Hohlkörpers mit dem Wirkmedium, wobei das Wirkmedium durch den Einlaufkanal über die daneben befindliche Öffnung in den Hohlkörper einströmt;
• - Schließen des Werkzeugs und Anfahren bzw. Anlegen von Dichtstempeln an die Öffnungen des Hohlkörpers (wenigstens wird ein Dichtstempel an eine Öffnung des Hohlkörpers angelegt);
• - Umformen, d. h. Innenhochdruckumformen des Hohlkörpers (eigentlicher Umformprozess), wozu über wenigstens einen der Dichtstempel ein (hoher) Innendruck aufgebracht wird;
• - Zurückfahren der Dichtstempel, gegebenenfalls Ablassen des Wirkmediums, Öffnen des Werkzeugs und Entformen des Bauteils.

The inventive method for producing a component by hydroforming using a tool according to the invention comprises the steps:

• - Inserting the reshaped hollow body in the lower tool (with the tool open), such that there is an opening of the hollow body adjacent to the mouth of the inlet channel into the cavity;
• - Prefilling (flooding) of the hollow body with the active medium, wherein the active medium flows through the inlet channel via the adjacent opening in the hollow body;
• Closing the tool and starting or applying sealing punches to the openings of the hollow body (at least one sealing stamp is applied to an opening of the hollow body);
• - Forming, ie hydroforming of the hollow body (actual forming process), for which a (high) internal pressure is applied via at least one of the sealing plunger;
• - Retracting the seal, possibly draining the active medium, opening the tool and removal of the component.

As already explained, the pre-filling of the inserted hollow body and the closing of the tool at the same time, d. H. temporally overlapping.

When prefilling the sealing punches can be positioned in front of the other openings of the inserted hollow body (via the no pre-filling), that a stowage of the active medium in the hollow body is possible or a back pressure arises, but still air can escape.

The component to be produced is in particular an automobile or motorcycle component, such. As an axle (eg. A longitudinal tube for an axle carrier) or a body structure part (eg., A lower windshield cross member or cowl).

• 1 zeigt ein erfindungsgemäßes Werkzeug und veranschaulicht in vier schematischen Schnittdarstellungen den erfindungsgemäßen Verfahrensablauf zur Herstellung eines Bauteils durch Innenhochdruckumformen (IHU).

The invention will be explained in more detail by way of example with reference to the drawing. The features shown in the figures of the drawing and / or explained below may be, even independently of concrete combinations of features, general features of the invention and further develop the invention accordingly.

• 1 shows a tool according to the invention and illustrates in four schematic sectional views of the process sequence according to the invention for the production of a component by hydroforming (hydroforming).

The tool 100 includes a lower tool 110 and an upper tool 120 that a cavity 130 for receiving a metallic hollow body to be formed 200 form. The lower tool 110 is arranged on a press table, not shown, and the upper tool 120 is attached to a press ram, not shown, (hold-down). In the reshaped hollow body 200 For example, it is a tubular blank having a first end opening 210 and a second end opening 220 , The lower tool 110 has funds 170 , such as B. magnet holder, for fixing the reshaped hollow body 200 on. To the tool 100 also include a first sealing stamp 140 and a second sealing stamp 150 that go along a major axis L are axially movable. In 1a Both seals are located 140 / 150 in rest positions.

The lower tool 110 also has an inlet channel 180 to pre-fill the cavity 130 inserted hollow body 200 with active medium. The inner end or the mouth 181 of the inlet channel 180 into the cavity 130 is located between the first opening 210 of the inserted hollow body 200 and at rest first seal first 140 , In the direction of the main axis L is not a distance between the mouth 181 and the first opening 210 or the opening edge of the inserted hollow body 200 available. The inlet channel 180 is designed as a single straight bore, in front of the first opening 210 the reshaped hollow body 200 into the cavity 130 opens, the bore axis 183 to the first opening 210 of the inserted hollow body 200 or in the hollow body 200 is aligned in it. The bore axis 183 and the longitudinal or major axis L intersect inside the hollow body 200 , The hole 180 extends obliquely through the lower tool 110 and is at its outer end with a connection 182 educated.

For forming the hollow body 200 this is when the tool is open 100 into the lower tool 110 inserted as in 1a shown. Even before the tool 100 by lowering the upper tool 120 is closed, the hollow body 200 over the inlet channel 180 with active medium W prefilled, as in 1b illustrated by the arrow. The active medium W can be directly into the hollow body 200 inflow, whereby a fast pre-filling with only slight turbulence is achieved. Meanwhile, the second sealing stamp 150 before the second opening 220 of the hollow body 200 positioned so that the active medium W in the hollow body 200 Dammed but still air can escape. The second sealing stamp 150 this is not quite the second opening 210 moved up. The filling time can be less than a second.

After the hollow body 200 filled, both are sealing stamp 140 / 150 placed in working or sealing positions, as in 1c shown. When approaching the first opening 210 closes the first seal 140 the estuary 181 of the inlet channel 180 , The hollow body 200 is now transformed by applying a high internal pressure, as in 1d shown. To generate the internal high pressure, the sealing stamp 140 / 150 z. B. have passageways which are connected to a high-pressure generating plant, as known from the prior art. Also in 1d shown axial Nachschieben the sealing stamp 140 / 150 is known from the prior art.

LIST OF REFERENCE NUMBERS

100

Tool

110

lower tool

120

upper tool

130

cavity

140

Sealing stamp (sealing cap)

150

Sealing stamp (sealing cap)

170

fixer

180

Inlet channel (hole)

181

muzzle

182

connection

183

bore axis

200

hollow body

210

Hollow body opening

220

Hollow body opening

L

main axis

W

active medium

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 19628688 C1 [0004]
• DE 10343868 B3 [0005]

Claims (10)

Tool (100) for hydroforming metallic hollow body (200) by means of active medium (W), with an upper tool (120) and a lower tool (110) formed with a cavity (130) for receiving a hollow body (200), wherein the Lower tool (110) has an inlet channel (180) for prefilling a hollow body (200) with active medium (W) inserted into the cavity (130), characterized in that the inlet channel (180) is arranged in front of an opening (210) of the inserted hollow body (200 ) into the cavity (130) and aligned with the opening (210) of the inserted hollow body (200). Tool (100) after Claim 1 , characterized in that the inlet channel (180) is formed as a straight bore. Tool (100) after Claim 1 or 2 , characterized in that the inlet channel (180) is designed as a slot hole. Tool (100) according to one of the preceding claims, characterized in that the mouth (181) of the inlet channel (180) is not more than 5 mm from the opening (210) of the inserted hollow body (200) spaced. Tool (100) according to one of the preceding claims, further comprising at least one movable sealing punch (140), with which the opening (210) of the inserted hollow body (200) is sealable, wherein the sealing punch (140) when approaching the opening (210) the mouth (181) of the inlet channel (180) closes. Tool (100) according to one of the preceding claims, characterized in that the inlet channel (180) is formed at the end remote from the mouth (181) end with a connection (182). Tool (100) according to one of the preceding claims, characterized in that the lower tool (110) has means (170) for fixing the inserted hollow body (200). A method of manufacturing a component by hydroforming with a tool (100) according to any one of the preceding claims, comprising the steps of: - Inserting a hollow body (200) to be formed in the lower tool (110), such that an opening (210) of the hollow body (200) adjacent to the mouth (181) of the inlet channel (180) is located; - Prefilling the hollow body (200) with active medium (W), which flows through the inlet channel (180) directly into the inserted hollow body (200); Closing the tool (100) and applying sealing punches (140, 150) to the openings (210, 220) of the hollow body (200); - Forming of the hollow body (200), for which via at least one of the sealing ram (140, 150), an internal pressure is applied; - Retracting the sealing stamp (140, 150), opening the tool (100) and demolding of the component. Method according to Claim 8 , characterized in that the prefilling of the inserted hollow body (200) and the closing of the tool (100) take place simultaneously. Method according to Claim 8 or 9 , characterized in that during the pre-filling in front of the other openings (220) of the inserted hollow body (200), the sealing rams (150) are positioned such that a stowage of the active medium (W) in the hollow body (200) is possible, but air can escape.

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