EP2654989B1 - Casting device for a piston for an internal combustion engine and method for opening and/or closing a casting device - Google Patents

Description

Technical area

The invention relates to a casting device for a piston for an internal combustion engine and to a method for opening and / or closing a casting device according to the preamble of claims 1 and 7, respectively.

State of the art

When casting pistons for internal combustion engines, there is a particular challenge in forming the piston into a mold with as few lost cores as possible, which has to be reworked as little as possible and is optimized with regard to weight saving.

To form recesses below the ring field of the piston, it is out of the DE 199 22 809 A1 known to provide a pivotable core for forming such a recess in addition to a linearly displaceable sleeve.

According to the US 2008/0257518 A1 suitable cores for forming the recesses under the ring field, which are used as Kühlausnehmungen, largely linear and obliquely with respect to the quills process.

Presentation of the invention

The invention has for its object to simplify an apparatus and a method for casting a piston for an internal combustion engine and at the same time to allow as extensive as possible the formation of recesses for weight savings.

The solution of this object is achieved on the one hand by the device described in claim 1.

Accordingly, this has at least one largely linearly movable quill to form at least one piston pin bore. The quill is thus a component which, at its end directed towards the casting cavity, has a largely cylindrical section which leaves a cavity for the piston pin bore on the finished piston. In particular, at the areas directed away from the casting cavity, the sleeve can have sections with a larger diameter and measures for coupling to a drive or, as described below, at least indirectly with the slide.

In the casting apparatus according to the invention, at least one slide, which can be moved substantially linearly and at an angle to the sleeve, is provided on the piston for forming at least one recess below the ring field. The travel of the slide results from the fact that the recesses under the ring field typically extend at an acute angle to the piston axis and thus obliquely to the axis of the quills extending perpendicular to the piston axis. In accordance with the invention, the quill is at least indirectly coupled to the slide in such a way that the quill at least partly entrains the slide during the process. This coupling can be designed, for example, when the casting device is opened in such a way that the sleeve is initially pulled back a little way is, and then a portion of the quill so at least indirectly engages the slider that it is moved obliquely to the quill. In other words, the quill is coupled to the slide, in particular for the opening movement, in such a way that it "takes along" it as part of a pulling movement. In addition, this coupling can also be effective when closing in the context of a "pushing" movement.

When closing the casting device, the process can take place substantially in the opposite direction, wherein it is currently preferred to effect a movement of the slide back into its closed position over substantially the entire closing movement of the sleeve. The slider expediently has a projection which forms the positive shape of the desired recess and is widening in the direction of movement for a particularly simple retraction when the mold is opened. The casting apparatus further includes any molds (halves) required for casting a complete piston. Further, both the sleeve and the slider are preferably provided in duplicate, to form the necessary configurations on both sides of the piston. Finally, the quill can pass through an opening in the slide. Advantageously, common casting devices do not have to be rebuilt. Compared to a pivoting movement of casting cores to form recesses under the ring field also results in the advantage that the recesses can be made deeper, and thus a more extensive weight savings is possible.

Preferred developments of the casting device according to the invention are described in the further claims.

Preferably, the slider is guided in at least one guide. As a result, the movement of the slider can be defined very precisely. At the same time, the coupling with the quill are made flexible in a certain frame, so that the guide can be interchangeable and / or, for example changeable in terms of angle, without having to change the coupling with the quill.

Accordingly, it is further preferred that the guide is replaceable. This offers the advantage of being able to adapt the travel path of the slide to different piston geometries. Alternatively or additionally, the angle provided by the guide with respect to the travel of the sleeve can be changed.

For the coupling between slide and quill a so-called pivoting fork is currently preferred, with which the slide is connected at least indirectly and at least to some extent pivotally. Here, the pivoting fork is pivotable through the sleeve, so that the quill "takes along" the slider by means of the pivoting fork.

In particular, with regard to the possibility to change the travel of the slider by replacing at least one guide and / or setting a different angle, it offers advantages when the slider is further coupled at least slightly displaceable with the pivoting fork.

With regard to the coupling between the quill and the slide by means of the pivoting fork, at least one pin on the quill, which can be brought into engagement with a projection and / or a sliding surface on the pivoting fork, is also currently preferred. The engagement with a projection is currently preferred for take-along when opening, while the interaction with a sliding surface in the context of the closing movement offers advantages.

The solution of the above object is further achieved by the method described in claim 7, after which a largely linearly movable quill at least one largely linear and oblique to the quill movable slider at least partially entrains. The preferred developments of the device are applicable to the inventive method. Furthermore, any method features described in connection with the device can be used in the method according to the invention.

Brief description of the drawings

Fig. 1

eine Seitenansicht eines Teils der erfindungsgemäßen Gießvorrichtung;

Fig. 2

eine erste Schnittansicht der in Fig. 1 gezeigten Gießvorrichtung in einem geschlossenen Zustand;

Fig. 3

eine zweite Schnittansicht der in Fig. 1 gezeigten Gießvorrichtung in einem geschlossenen Zustand;

Fig. 4

eine erste Schnittansicht der in Fig. 1 gezeigten Gießvorrichtung in einem teilweise zurückgezogenen Zustand der Pinole;

Fig. 5

eine zweite Schnittansicht der in Fig. 1 gezeigten Gießvorrichtung in einem teilweise zurückgezogenen Zustand der Pinole;

Fig. 6

eine erste Schnittansicht der in Fig. 1 gezeigten Gießvorrichtung in einem vollständig zurückgezogenen Zustand der Pinole; und

Fig. 7

eine zweite Schnittansicht der in Fig. 1 gezeigten Gießvorrichtung in einem vollständig zurückgezogenen Zustand der Pinole.

Hereinafter, an embodiment of the invention shown by way of example in the drawings will be explained in more detail. Show it:

Fig. 1

a side view of a part of the casting apparatus according to the invention;

Fig. 2

a first sectional view of the in Fig. 1 shown casting device in a closed state;

Fig. 3

a second sectional view of the in Fig. 1 shown casting device in a closed state;

Fig. 4

a first sectional view of the in Fig. 1 shown pouring device in a partially retracted state of the quill;

Fig. 5

a second sectional view of the in Fig. 1 shown pouring device in a partially retracted state of the quill;

Fig. 6

a first sectional view of the in Fig. 1 shown pouring device in a fully retracted state of the quill; and

Fig. 7

a second sectional view of the in Fig. 1 shown pouring device in a fully retracted state of the quill.

Detailed description of a preferred embodiment of the invention

In Fig. 1 a section of the casting device according to the invention is shown, wherein in the side view of Fig. 1 in the first place a guide 14 for the linear movement of a slider 12 in the direction A can be seen. Furthermore, in Fig. 1 one of which (according to Fig. 1 located on the left) casting cavity facing away from the sleeve 10 can be seen, which is movable in the direction B. Thus, the directions A and B are oblique to each other. As will be explained in more detail below, the sleeve 10 and the slider 12 are coupled by means of a pivoting fork 16, which is pivotable about an axis 24 in a direction C. The mentioned coupling takes place in the example shown via a pin 18 which is engageable when opening with a projection 20 on the pivoting fork 16 and when closing with a sliding surface 22 on the pivoting fork in engagement.

Out Fig. 2 that the state of Fig. 1 It can also be seen that the sleeve 10 extends through an opening in the slider 12, and that the slider 12 according to the figures in the upper region has a nose-like projection 26 for forming a recess below the annular field of a piston.

Furthermore, in Fig. 3 to recognize the coupling between the slider 12 and the pivoting fork 16, which consists in that a widened, free end 28 of the pivoting fork 16 is inserted into a cavity 30 in the slider such that a linear movement can be transmitted, further in Fig. 7 can be seen, a slight pivoting movement is made possible, and also a certain linear displacement (according to the figures from right to left) is allowed. This mobility is due to the determination of the movement of the slider by the guide (see. Fig. 1 ) low, since the movement of the slide can be defined by the guide in the said degrees of freedom between the slide and the pivoting fork, but can be transmitted through the fork on the slider.

While the FIGS. 2 and 3 correspond to the closed state of the casting apparatus and both quill and slide are in a casting position is in 4 and 5 an intermediate position shown, in which the casting device is still closed, but the quill 10 is partially retracted, while the slider 12 is still in a casting position. In Fig. 5 It can be seen that the pin 8 on the quill is just with the projection 20 on the pivoting fork 16 is engaged to start the entrainment of the slider 12.

Out Fig. 6 results in the final position in which the sleeve 10 is moved back a maximum, the slider is cleared and the casting device can thus be opened. Based on the position of the pivoting fork 16 it can be seen that this has been pivoted at least slightly counterclockwise, and thereby, in particular in Fig. 7 shown, the slide whose movement continues through the guide 14 (see. Fig. 1 ), took with him. Since in the example shown, the travel of the slider is relatively steep, the free end 28 of the pivot fork 16 has moved out of the cavity 30 of the slider 12 a little.

When the casting apparatus starting from the in Fig. 7 If the state is to be closed, the quill is again in the in the Fig. 1 to 3 shown state. In this case, the pin 18 slides on the sliding surface 22 of the pivoting fork, which as a result returns the slider 12 in the fully retracted position.

Claims (7)

1. Casting device for a piston for an internal combustion engine having at least one sleeve (10) which can be moved at least largely linearly to form at least one piston pin bore and at least one slider (12) which can be moved at least largely linearly and at an angle to the sleeve (10) to form at least one recess below a ring zone of the piston, characterised in that the sleeve (10) and the slider (12) are coupled at least indirectly such that the sleeve at least partly drives the slider (12) during the movement.
2. Casting device according to claim 1, characterised in that the slider (12) is guided in at least one guide (14).
3. Casting device according to claim 2, characterised in that the guide (14) can be exchanged and/or its angle can be changed.
4. Casting device according to one of the preceding claims, characterised in that the slider (12) is coupled at least indirectly and pivotably to a pivoting fork (16) which can be pivoted by the sleeve (10).
5. Casting device according to claim 4, characterised in that the slider (12) is further coupled to the pivoting fork (16) to be at least slightly displaceable.
6. Casting device according to one of claims 4 or 5, characterised in that the sleeve (10) has at least one peg (18) which can be engaged with a projection (20) and/or a sliding surface (22) on the pivoting fork (16).
7. Method for opening and/or closing a casting device for a piston for an internal combustion engine, in which at least one sleeve (10) which can be moved largely linearly at least partly drives at least one slider (12) which can be moved largely linearly and at an angle to the sleeve (10).

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