DE102010011003A1 - Producing casting parts consisting of a recasting- and a core part, comprises arranging the core part inside a cavity of a casting tool by movably mounted positioning elements for bearing safety during the production of the casting parts - Google Patents

Abstract

The method for producing casting parts consisting of recasting part and a core part (8), comprises arranging the core part inside a cavity (7) of a casting tool (1), and keeping the core part inside the cavity by movably mounted positioning elements (15) for bearing safety during the production of the casting parts, where one of the positioning elements are moved-out from its core part-supporting position into the cavity with the not yet completely solidified casting part. A movably mounted secondary compression element (22) is moved into the cavity up to a distance above the core part. The method for producing casting parts consisting of recasting part and a core part (8), comprises arranging the core part inside a cavity (7) of a casting tool (1), and keeping the core part inside the cavity by movably mounted positioning elements (15) for bearing safety during the production of the casting parts, where one of the positioning elements are moved-out from its core part-supporting position into the cavity with the not yet completely solidified casting part. A movably mounted secondary compression element (22), which is adjacent to the one of the positioning element and is simultaneous or subsequent to the outward movement, is moved into the cavity up to a distance above the core part, so that the melt volume lying above the secondary compression element is displaced into the cavity by its movement and into the volume released from the moved-back or moving-back positioning element through its lesser distance to the assigned positioning element. The positioning element is a positioning pin and the secondary compression element is a secondary compression pin, where the positioning pin and the secondary compression pin are displaced axis-parallel to each other with respect to the core part in a controlled manner. The outwardly moving all existing positioning elements are simultaneously introduced with the inwardly moving all second compression elements. The positioning elements are moved out from the cavity until they are in flush-mounted position with a contour of mold halves forming the cavity and the secondary compression elements are moved from the flush-mounted position into the cavity up to the distance above the core part. The core part is held as reinforcing element on both sides of the aligned positioning pins but the secondary compression pin is assigned only to the positioning pin, where the secondary compression pin displaces a molten casting metal into the reinforcing element by a passage opening lying before it and into the volume released from the positioning pin at the rear side of the reinforcing element during the simultaneous outward movement of the positioning pins. An independent claim is included for a casting tool for producing casting parts consisting of recasting part and a core part.

Description

The invention relates to a method for producing a cast part according to the preamble of claim 1 and to a casting tool for carrying out the method according to the preamble of claim 6.

The pouring / encapsulation of thin-walled, large-area reinforcing components in cast metal parts, in particular in light metal structures, as used in modern motor vehicles, leads to locally improved properties over an unreinforced component. With such reinforced components, a weight-optimized component design is achieved with maximum functionality.

For this purpose, a generic method ( DE 10 2008 004 023 A1 ) for producing a casting consisting of at least one encapsulation and at least one core part as a reinforcing component, wherein the core part is arranged within a cavity of a casting tool and held there by movably mounted positioning elements for securing the position during production of the casting. In order to avoid interfering influences of these positioning elements, for example an impairment of the casting strength, according to this method, at least one of the positioning elements is moved out of its cavity with its casting not fully solidified, preferably into a flush position with a contour forming the cavity the respective mold half of the casting tool. Next to be filled and potted by a targeted increase in pressure by means of the casting piston in a so-called post-pressure phase, the exposed by the retracted positioning elements as positioning pins volumes in the casting with molten metal. This is to ensure that the core part is completely encapsulated as a reinforcing component at the contact points of the positioning.

However, the disadvantage is that the melt, which is in direct contact with the positioning element acting as a core support, solidifies faster than the adjacent material. As a result, it is not ensured that the volumes released by the withdrawn positioning elements are completely closed in the casting, so that binding errors can disadvantageously result. This is especially true for thin-walled components or component areas that are located away from the sprue, since here after the mold filling in the emphasis phase applied emphasis can no longer reach the affected component areas or no molten connection between the sprue and the released volumes longer exists.

The object of the invention is therefore to develop the generic method for producing a casting consisting of at least one encapsulation and at least one core part as a reinforcing component so that the resulting by the moving out of the cavity positioning elements volumes safely and completely filled with melt and closed , Another object of the invention is to propose a suitable casting tool.

The object is achieved with respect to the method in that each adjacent to the at least one positioning simultaneously or subsequently to the outward movement at least one movably mounted Nachverdichterelement is moved into the cavity to a distance in front of the core part. As a result, the melt volume lying in front of the postcompressor element is displaced by its movement into the cavity and by its short distance from the associated positioning element into the volume released by the retracting or moved back positioning element.

It is essential that the core part as a reinforcing element in the region of the withdrawn positioning elements is securely completely covered with encapsulation material by the Nachverdichterelemente moved into the cavity. On the one hand, this is achieved by the fact that the Nachverdichterelement is moved into the cavity only up to a distance in front of the core part and on the other hand so much molten Umgussmaterial is displaced, that the contact area and the released volume of the associated positioning element are filled. The ultimately remaining through the Nachverdichterelement in the casting opening does not interfere. Optionally, recesses in the casting can also be left behind by the retracted positioning elements, which likewise do not disturb, as long as the core part as a reinforcing element in these areas is securely covered with encapsulation material.

The above method is easy to carry out if the at least one positioning element is designed as a positioning pin and the at least one after-compressor element as a post-compression pin (squeezepine), which are displaced in a controlled manner with respect to the core part with respect to the axis. Squeezepins for a local pressure increase in the melt are generally off for other applications, for example US 2007/0193712 A1 known.

The exact process flow can be very well controlled due to the current control and regulation capabilities of the real-time regulated die casting machines.

Ideally, the moving out of the positioning elements occurs simultaneously to the forward movement of the Nachverdichterelemente to minimize the time required for the process. Thus, the temperature loss is reduced as a relevant size for the time available as much as possible.

In order that the withdrawn positioning elements leave no depressions in the casting as far as possible, it is proposed to move them out of the cavity until they are in a flush position with a contour of mold halves of the casting tool forming the cavity. On the other hand, it is expedient to move the Nachverdichterelemente from such a flush position in the cavity to a distance in front of the core part. In order to reduce the expense for Nachverdichterelemente, it is proposed that the core part is held as a reinforcing element on both sides of aligned associated positioning pins, but only one positioning pin is associated with a Nachverdichterstift. This Nachverdichterstift displaced while simultaneously moving out of the positioning pins through an opening in front of him in the reinforcing element molten casting metal on the back of the reinforcing element in the released from the local positioning pin volume. This closed by two opposite positioning pins openings are closed by only one Nachverdichterstift.

The object of the invention is achieved with respect to the casting tool in that at least to a portion of the positioning pins adjacent axially parallel controlled movable Nachverdichterelemente are arranged as Nachverdichterstift (Squeezepins).

Excellent process results are achieved with the following dimensions:
With a locator pin diameter (d), the booster stylus diameter (D) is made larger, about 1.5 to 2.5 times (d), preferably about 2 times (d). Thus, sufficient Nachdruckvolumen retained for the Nachverdichterstift.

The center distance (h) of the positioning pin and the Nachverdichterstifts be less than 3 times the Nachverdichterstift diameter (D) selected. Thus, the required proximity between the Nachverdichterstift and the associated positioning is guaranteed.

Further, it is expedient to round off the Nachverdichterstift on its front with a radius (R) corresponding to about 2 times the Nachverdichterstift diameter (D).

Advantageously, a material reservoir for the recompression is already formed in the mold in the region in front of a post-compressor pin and optionally an associated positioning pin.

An opening in a reinforcing element for permeating molten casting metal should expediently be positioned approximately between the axes of the positioning pins and the associated post-compression pin. In this case, the opening may be designed arcuate with respect to the volume released by the rear positioning pin and this partially surrounding. The geometric shape of the opening in the reinforcing element is thus chosen so that the distance to the occluding opening in the casting is minimal.

In a structurally simple embodiment, the adjusting elements can be designed as lifting cylinder units which act directly or via intermediate carrier plates on the positioning and / or Nachverdichterelemente.

Reference to a drawing, the invention will be further explained.

Show it:

1 a side view of a casting tool with the functionally relevant components for carrying out the method according to the invention,

2 an enlarged scale representation of the detail A after 1 .

3 a plan view of the finished casting in the area A, and

4 a plan view of the reinforcing element in the region A with a flow-through.

An in 1 shown casting tool 1 consists of one on a foundation 2 fixedly positioned first mold half 3 and a corresponding thereto, in the horizontal direction movable (double arrow 4 ) and of a closing unit 5 acted upon second half of the mold 6 ,

When closed, as in 1 is shown, close both mold halves 3 . 6 a cavity 7 a, whose contour ultimately corresponds to the shape of a casting formed as a composite casting. Inside the cavity 7 is as a reinforcing element 8th arranged for the casting serving core part, which of one, the remaining cavity of the cavity 7 enclosing infusion is enclosed.

In the area of the first half of the mold 3 is on the foundation a known casting unit 9 arranged, which is a molten metal 10 containing filling chamber 11 has, wherein the molten metal 10 during the casting process via a casting piston 12 and a connection channel 13 into the cavity 7 is pressed.

As can be seen from the synopsis of 1 and 2 gives, is the reinforcing element 8th on both sides of positioning pins 14 . 15 acted upon. The positioning pins 14 . 15 are axially movable within the first and second mold halves, respectively 3 . 6 guided and individually or jointly via hydraulically or pneumatically operated lifting cylinder units 18 . 19 into the cavity 7 movable in and out.

Next is inside the second half of the mold 6 one from another lift cylinder 20 displaceable positioning pin 21 axially movable leads to the reinforcing element 8th attachable for pre-positioning.

In addition, the two positioning pins 15 each adjacent an axially parallel controlled movable Nachverdichterstift 22 assigned, with both Nachverdichterstifte 22 coupled via another lifting cylinder 23 are relocatable. Further details will be described below with reference to the enlarged illustration 2 explains:
The positioning pins 14 . 15 have a diameter d, wherein the Nachverdichterstift 22 has a diameter D twice as large. The center distance between the positioning pin and the post-compressor pin 22 h is slightly smaller than three times the diameter of the post-compactor pin 22 , The Nachverdichterstift 22 is rounded off in front with a radius of about the order of magnitude 2D ,

The mold half 6 has in the area of the positioning pin 15 and Nachverdichterstifts 22 a recess 24 as a melt material reservoir. For example, in the flight between the positioning pin 15 and the post-compressor pen 22 is a flow opening 25 in the reinforcing element 8th , The in 2 Area A shown corresponds in mirror image to an identically constructed area in the lower part of the cavity.

According to the procedure according to the invention, the reinforcing element is initially open when the casting tool is open 8th for pre-positioning on the positioning pin 21 attached. Subsequently, the casting tool 1 by shifting the mold half 6 by means of the closing unit 5 closed. Subsequently, the positioning pins 14 . 15 moved up to the reinforcing element, whereby the reinforcing element 8th precisely positioned and held. The pre-positioning pin 21 can now be withdrawn again.

Molten metal, in particular light metal, is supplied to the filling chamber via a metering furnace and via the casting piston 12 and the connection channel 13 into the cavity 7 pressed. Favorable are large section thicknesses> 5 mm and low filling speeds <1 m / s.

If not completely solidified casting the positioning pins 14 . 15 up to one position 26 corresponding to the rear surface of the recess 24 withdrawn.

After the end of the mold filling, preferably simultaneously with the retraction of the positioning pins 14 . 15 becomes the post-compressor pen 22 in the in 2 dashed line position 27 with a distance 28 to the reinforcing element 8th extended and into the cavity 7 inside moves. That before the post-compressor pen 22 located melt volume is in the associated from the positioning pin 15 released volume displaced because of the small distance of the positioning pin 15 and the post-compactor pen 22 the casting metal in between is at least partially molten. It also flows through the reinforcement element 8th included flow opening 25 the still liquid metal on the back of the reinforcing element 8th and closes there by the withdrawal of the positioning pin 14 released volumes. This closes off the Nachverdichterstift 22 displaced metal in the surrounding by the withdrawal of the positioning pins 14 . 15 remaining openings cohesively and the reinforcing element 8th is sure completely encapsulated.

After complete solidification of the casting becomes the casting tool 1 opened and the composite casting consisting of casting and reinforcing element 8th can be removed from the pouring device.

In 3 is a plan view of a finished casting 29 in a partial area A with viewing direction according to arrow 30 out 2 shown. The negative form of the recess 24 in the cavity corresponds to the positive shape of an attached dome 31 on the finished casting 29 , The recess 24 or the cathedral 31 serves as a casting material reservoir for the post-compressor pin 22 , where on Dom 31 the from the positioning pin 15 and from the post-compressor pen 22 originating contours 32 . 33 can be seen.

In 4 is also in the direction of view 30 a plan view of the portion A on the reinforcing element 8th with the flow opening 25 shown. Dashed lines are the positions of the positioning pin 15 and the post-compactor pen 22 located. How out 4 can be seen, the flow-through 25 approximately aligned between the positioning pin and the Nachverdichterstift 22 with a slit-shaped and arcuately curved shape. Due to this geometric shape, the distance to the occlusive opening in the back Umgussbereich through the retracted positioning pin 14 minimal.

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 102008004023 A1 [0003]
• US 2007/0193712 A1 [0008]

Claims (11)

A method for producing a casting consisting of at least one Umgoss- and at least one core part, wherein the core part is disposed within a cavity of a casting tool and held there by movably mounted positioning elements for securing position during the production of the casting and at least one of the positioning elements in not yet completely solidified Casting part is moved out of its core part supporting position in the cavity, characterized in that in each case adjacent to the at least one positioning element ( 15 ) at least one movably mounted secondary compressor element (or 22 ) into the cavity ( 7 ) to a distance ( 28 ) in front of the core part ( 8th ) is moved in, so that the before the Nachverdichterelement ( 22 ) melt volume by its movement in the cavity ( 7 ) and by its short distance to the associated positioning element ( 15 ) in the moving from the back or moved positioning ( 15 ) released volume is displaced. A method according to claim 1, characterized in that the at least one positioning element is a positioning pin ( 15 ) and the at least one secondary compressor element a Nachverdichterstift ( 22 ) (Squeezepine) which are axially parallel to each other with respect to the core part ( 8th ) are moved under control. Method according to claim 1 or 2, characterized in that the removal preferably of all the existing positioning elements ( 14 . 15 ) simultaneously with the moving in preferably all the secondary compressor elements ( 22 ) is initiated. Method according to one of claims 1 to 3, characterized in that the positioning elements ( 14 . 15 ) so far out of the cavity ( 7 ) are moved out until they are in a flush position with a cavity ( 7 ) forming contour of mold halves ( 3 . 6 ) of the casting tool ( 1 ) and on the other hand the Nachverdichterelemente ( 22 ) from such a flush position into the cavity ( 7 ) to a distance ( 28 ) in front of the core part ( 8th ) are moved into it. Method according to one of claims 1 to 4, characterized in that the core part as reinforcing element ( 8th ) each on both sides of aligned associated positioning pins ( 14 . 15 ), but only one positioning pin ( 15 ) a post-compressor pen ( 22 ), which Nachverdichterstift ( 23 ) while simultaneously moving out the positioning pins ( 14 . 15 ) through a flow opening in front of it ( 25 ) in the reinforcing element ( 8th ) molten cast metal also on the back of the reinforcing element ( 8th ) into the locating pin ( 14 ) displaced volumes displaced. Casting tool for carrying out the method according to one of claims 1 to 5, consisting of a first mold half and a corresponding thereto, movable via a closing unit second mold half, which form a cavity in the closed state, whose contour corresponds to the shape of a casting to be produced, wherein a within the cavity located Kernteil is held by positioning elements, wherein the positioning elements are arranged as positioning individually or jointly controlled via controllable adjusting elements within the mold halves axially movable, characterized in that at least a portion of the positioning pins ( 15 ) adjacent parallel to the axis controlled movable Nachverdichterelemente as Nachverdichterstifte ( 22 ) are arranged. Casting tool according to claim 6, characterized in that at a positioning pin diameter (d) of the Nachverdichterstift diameter (D) is greater than 1.5 to 2.5 times (d), preferably about 2 times (d) dimensioned, and that the center distance (h) of the positioning pin (h) 15 ) and the Nachverdichterstifts ( 22 ) is smaller than three times the post-compressor pin diameter (D), that is h <3D is selected. Casting tool according to claim 7, characterized in that the post-compression pen ( 22 ) is rounded at its front with a radius (R) corresponding to about twice the Nachverdichterstift diameter (D), that is R ≈ 2D. Casting tool according to one of claims 6 to 8, characterized in that in the mold half ( 6 ) in the region of a Nachverdichterstifts ( 22 ) and an associated positioning pin ( 15 ) a recess ( 24 ) is formed as a material reservoir for the densification. Casting tool according to one of claims 6 to 9, characterized in that a flow-through opening ( 25 ) in a reinforcing element ( 8th ) for displacing molten casting material approximately between the axes of the positioning pins ( 14 . 15 ) and the associated Nachverdichterstifts ( 22 ), wherein the flow-through opening ( 25 ) arcuately with respect to that of the rear positioning pin ( 14 ) volume is executed. Casting tool according to one of claims 6 to 10, characterized in that the adjusting elements as Hubzylindereinheiten ( 18 . 19 . 20 ) educated are the directly or via intermediate carrier plates on the positioning ( 14 . 15 ) and / or Nachverdichterelemente ( 22 ).

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