JP2015528538A - Piston mold - Google Patents

Abstract

The present invention relates to a substantially annular casting core (3) that can be disassembled to form a cooling channel (4) and at least two supports (5, 6) that support the casting core (3) during casting. ) For a piston (2) of an internal combustion engine. An obstruction or closure element (15) is arranged at the connection between at least one of the supports (5, 6) and the support (9) and the casting core (3). The obstruction or closure element (15) is joined with the piston (2) after casting, and after removal of the casting core (3), the closure of the connecting part, the formation of an intermediate drainage channel (14) with a narrowed flow path. Do one of the following. Therefore, the stability of the mold (1) can be improved and the handling thereof can be simplified.

Description

  The present invention relates to a mold for a piston of an internal combustion engine, which is provided with the disassembling substantially annular mold core according to the preamble portion of claim 1. The invention further relates to a casting piston for an internal combustion engine and a method for producing such a casting piston.

  A general mold for a piston of an internal combustion engine, which is provided with a substantially annular mold core that can be disassembled to form a cooling channel, is known from DE 19804168. is there. The mold core is supported by two supports (so-called quills). These support members later form a liquid supply path and a liquid discharge path of the annular cooling flow path in a region communicating with the mold core.

  The center line of each support can be inclined with respect to the outer periphery of the piston, and the tip thereof is in contact with a mold core that is disposed on the outer periphery of the piston and can be disassembled. This makes it possible in particular to form a piston with improved strength.

  The known mold is not suitable for supporting the mold core that forms the cooling flow path because the liquid supply path and the drainage path of the cooling flow path are arranged close to each other.

  The present invention addresses the problems of an improved embodiment or at least an alternative embodiment of a general mold for internal combustion engine pistons, and the mold of the present invention is particularly improved in stability and manufactured with this mold. It features improved piston cooling power.

  According to the invention, this problem is solved by the subject matter of the independent claims. Preferred embodiments are the subject matter of the dependent claims.

  The present invention is based on the following basic concept. That is, in a piston mold of a known internal combustion engine, a substantially annular casting core that can be disassembled to form a cooling flow path, and at least two supports that support the casting core during a casting process; .

  An obstruction or closure element is arranged at the connection between at least one of the two supports or an additional third support and the casting core. The blocking or closing element remains in the piston at least partially firmly connected to the piston after the casting process. The obstructing or closing element closes the connecting portion after removal of the casting core or forms an intermediate drainage channel with at least a narrowed flow path.

  In this case, the blocking or closing element is a closing element and seals the cooling channel.

  As an alternative to this, an intermediate drainage path is formed by forming a constricted channel connecting portion that communicates with the cooling channel at the end facing the cooling channel in the blocking or closing element. Can be easily assumed.

  Practical cooling channel supply and drainage channels can be formed via one or two supports, or through post-processing of drilling holes in the cooling channels through these supports.

  In each embodiment of the obstruction or closure element, if no connection for introducing liquid into the cooling channel is formed, such an obstruction or closure element is a simple closure element and the corresponding support is It provides a simple support for securing the casting core during the casting process.

  If the obstruction or closure element forms a connection part with a narrowed flow path (small cross section) leading to the cooling flow path at the connection part with the cooling flow path, an intermediate drainage path is formed at this connection part it can.

  According to a preferred embodiment, to support the casting core, a third support is provided, the first two mentioned being placed adjacent to each other and later supplied to the cooling channel A channel and a drainage channel are formed.

  In the present invention, the third support for supporting the casting core is provided on the opposite side of the two supports in the casting core. This third support forms an intermediate drainage channel for the cooling channel, and its cross-sectional area is greatly reduced.

  To that end, the third support is provided with a blocking or closing element having a pin that enters the casting core, to which a sleeve is attached. In this case, the outer diameter of the pin is much smaller than the outer diameter of the sleeve.

  As a result, the diameter of the intermediate drainage channel when the pin is removed after casting corresponds to the diameter of the pin, not the sleeve. The pin is removed, but the sleeve remains in the piston after casting. For example, a dismantleable casting core that can be formed as a sand or salt core is similarly removed by a known method.

  With the third support, a number of effects can be realized with respect to common molds. The first effect to be mentioned in this case is that the disassembling casting core that forms the cooling flow path is supported relatively stably by the three supports, and the main liquid supply path and the main drainage liquid The path is provided at a location close to each other on one side of the cooling flow path.

  Since the blocking or closing element of the present invention comprises a pin and a sleeve attached to it, the diameter of the intermediate drainage channel and thus the cross-section can be further reduced. As a result, at least unintentional outflow of the refrigerant can be suppressed, and the cooling power of the piston manufactured by the mold of the present invention can be greatly improved.

  Compared with the drainage path on the opposite side of the liquid supply path in the conventional piston, the liquid supply path and the drainage path in the embodiment of the piston of the present invention are close to each other. Refrigerants such as cooling oil flowing into the cooling flow channel reach the entire cooling flow channel before flowing out of the cooling flow channel through the drainage channel.

  Although the cooling effect is thereby improved, since the liquid supply path and the drainage path are arranged on one side of the casting core, it becomes difficult to support the casting core. A third support is provided on the opposite side so that the casting core can be additionally supported, so that the casting core is significantly stabilized.

  However, if the third support is designed in the same manner as the first two supports, the refrigerant will not be at a location that has passed half of the cooling flow path, so that the desired cooling effect cannot be realized. Due to the obstruction or closure element of the present invention comprising a pin with a sleeve attached thereto, the third support can sufficiently exhibit a practical support effect without causing excessive outflow of refrigerant. The sleeve in this case constitutes an obstruction element.

  In practice, the obstructing or closing element or sleeve has an annular circumferential groove on its outside. While such an outer circumferential groove is very easily formed in terms of manufacturing, the casting material flows into such a circumferential groove when casting the piston, so that an obstructing or closing element or sleeve Is securely fixed to the cast piston.

  Instead of the outer circumferential groove, different external shapes such as a convex portion and a concave portion may be formed. These are securely connected to the casting material of the piston, and an obstructing or closing element or sleeve is more firmly fixed in the cast piston.

  When the solution of the present invention is further suitably developed, the outer diameter of the sleeve is about 4 to 5 mm (preferably about 4.5 mm), and the inner diameter is about 1 to 2 mm (preferably about 1.8 mm). It is.

  In this case, the outer diameter of the pin substantially matches the inner diameter of the sleeve (for example, 1.8 mm in this case). Compared to a conventional support whose outer diameter coincided with the inner diameter of the drainage passage formed later, the sleeve of the present invention reduces the diameter of the intermediate drainage passage from 4.5 mm to 1.8 mm, for example. it can. Therefore, the flow rate of the refrigerant that is drained through the intermediate drainage path can be greatly reduced.

  In practice, the sleeve is placed between the casting core and a negative mold (ie, another casting core). By inserting the pin into both the casting core and the negative mold, the casting core and the negative mold are fixed to each other.

  After casting of the piston, the casting core that forms the cooling flow path is disassembled (in particular, washed away). The pin is withdrawn from the sleeve, but the sleeve remains in the piston because the casting material of the piston is bonded to the circumferential groove of the sleeve.

  The pins and sleeves are made of metal (particularly steel or alloy steel). The pin not only has a function of supporting the casting core on the pin, but also has a function of fixing the casting core against the lateral displacement and lifting of the support.

  In a further preferred aspect of the invention, the obstruction or closure element comprises a pin that enters the casting core, and the obstruction or closure element has an axial hole-like recess on the opposite side of the pin. By means of the axial hole-shaped recess, the blocking or closing element can be fixed to the negative mold, for example, and is fixed to the casting core by pins that enter the casting core.

  Since the obstructing or closing element does not form a connecting portion for guiding the liquid or the intermediate drainage passage, by providing the obstructing or closing element, the casting core can be supported later without causing liquid leakage.

  The pin or sleeve may be designed as one part or as part. Further, the pin and the sleeve may be designed as a plurality of parts assembled to each other.

  Further important features and advantages of the invention are realized from the dependent claims, the drawings and the corresponding description of the drawings using the drawings.

It is a figure of the casting_mold | template concerning this invention. It is a figure of the casting piston cast using the mold concerning the present invention. It is detail drawing of the area | region of the 3rd support body in the casting_mold | template which concerns on this invention. It is a figure of the field of the 3rd support in a mold concerning an embodiment of the present invention. It is a figure of the area | region of the 3rd support body in the casting_mold | template which concerns on another embodiment of this invention. It is a figure of the area | region of the 3rd support body in the casting_mold | template which concerns on another embodiment of this invention. FIG. 6 is a diagram of a region of a third support in a mold according to a further embodiment of the present invention.

  It should be understood that the features described above and hereinafter described features may be used not only in the corresponding described combinations, but also in other combinations or alone without departing from the scope of the invention. It is.

  Preferred embodiments of the invention are described in more detail below in conjunction with the drawings. Like reference numerals in the description denote identical, similar, or functionally identical components.

  1 and 3 show the mold 1 of the present invention which is not shown otherwise. The mold 1 for the piston 2 (see FIG. 2) of the internal combustion engine includes a disassembling substantially annular casting core 3 (see FIG. 1) that forms a cooling channel 4 (see FIGS. 2 and 3), and a casting. In the process, two supports 5 and 6 for supporting the casting core 3 are provided. These two supports 5 and 6 later form a liquid supply path 7 and a liquid discharge path 8 of the cooling flow path 4 at the connecting portion with the casting core 3 (see FIG. 1).

  The cooling flow path 4 in this case is designed in an annular shape, and the annular shape is divided only in the region of the liquid supply path 7 and the drainage path 8. In a special embodiment of the invention, the two supports 5 and 6 are arranged adjacent to each other and on the opposite side of the casting core 3 from the liquid supply path 7 and the drain path 8 A third support 9 that supports the child 3 is provided.

  According to the invention, the blocking or closing element 15 is arranged at the connection between at least one of the two supports 5, 6 or an additional third support 9 and the casting core 3. Has been. At least a part of the blocking or closing element 15 after the casting process is firmly connected to the piston 2.

  The blocking or closing element 15 either closes the connecting portion after removal of the casting core 3 or forms an intermediate drainage path 14 with at least a narrowed flow path. Here, the blocking or closing element 15 comprises a pin 10 (see FIGS. 3 to 7) that enters the casting core 3 and a sleeve 11 that is mounted on the pin 10.

  The third support 9 can not only support the casting core 3 at the third position, but also can arrange the liquid supply path 7 and the drainage path 8 adjacent to each other. As a result, the overall more stable mold 1 can be realized.

The pin 10 connected to the blocking or closing element 15 or the sleeve 11 allows the diameter of the intermediate drain 14 formed by the pin 10 to be reduced from the diameter d ₁ to the diameter d ₂ (see FIG. 4), and the cross-sectional area is also reduced. it can. For this reason, the refrigerant material flowing out from the intermediate drainage channel 14 in the region of the third support 9 can be reduced.

  Here, the liquid supply path 7, the drainage path 8, and / or the intermediate drainage path 14 (support 9) are substantially orthogonal to the annular surface of the casting core 3, for example, as is apparent from FIG. 1. It may be formed so as to. The blocking or closing element 15 or sleeve 11 may further comprise a circumferential groove 12 (see FIGS. 3 and 4).

  After the pin 10 is removed to inject casting material during casting of the piston 2, the sleeve 11 is fixed in the piston 2 by this circumferential groove 12. It is obvious that other convex portions or concave portions may be formed on the outer peripheral surface of the sleeve 11 instead of the peripheral groove 12. These are connected to the casting material of the piston 2 in an undercut shape, so that the blocking or closing element 15 or the sleeve 11 is securely fixed in the cast piston 2.

  As shown in FIG. 4, it is clear that the sleeve 11 may have a smooth outer surface and need only be held on the casting material of the piston 2 by adhesive friction. The outer diameter of the sleeve 11 is, for example, about 4 to 5 mm (preferably about 4.5 mm), and the inner diameter of the sleeve 11 may be, for example, about 1 to 2 mm (preferably 1.8 mm).

  The inner diameter of the sleeve 11 substantially matches the outer diameter of the pin 10. The piston 2 may for example be cast from an aluminum alloy, in particular as a light metal piston. The material of the sleeve 11 and the pin 10 may in particular be an aluminum alloy or steel.

  The casting core 3 is supported by the pins 10 in a substantially vertical direction and is fixed against lateral displacement and lifting. As a result, an overall strong mold 1 can be created.

  As shown in FIG. 3, the sleeve 11 is disposed between the casting core 3 and the negative mold 13 (that is, a metal mold, a sand mold, or a salt mold), and the pin 10 is connected to the casting core 3 and the negative mold 13. These are fixed to each other by being inserted into the mold 13. The casting core 3 may be formed as a sand core or a salt core, for example.

  In general, a wide range of various embodiments are envisaged for the supports 5, 6, and 9, and these supports later function as a liquid supply path 7, a drain path 8, and an intermediate drain path 14, respectively. To do. When the supports 5, 6, 9 simply have a support function, it is conceivable that the liquid supply passage 7 and the drainage passage 8 are provided with holes in the cast piston 2.

  FIGS. 2 and 3 show an obstructing or closing element 15 with a sleeve 11, which is held on both the casting core 3 and the negative mold 13 via pins 10. By removing the pin 10, an intermediate drainage channel 14 with a reduced cross section is formed after the casting process. Here, the pin 10 may be long enough to penetrate the negative mold 13.

  FIG. 5 shows an obstruction or closure element 15 consisting of a pin 10 and a sleeve 11, which remains on the piston 2 after the casting process. Since the pin 10 remains in the piston 2 in the same manner, the cooling flow path 4 is firmly closed at the connecting portion with the support body 9, and thus there is no leakage.

  A similar embodiment is shown in FIG. Here, the pin 10 and the sleeve 11 are integrally formed, and the pin 10 and the sleeve 11 constitute an integral blocking or closing element 15.

  FIG. 7 illustrates an embodiment of an obstruction or closure element 15 comprising a pin 10 that enters the casting core 3. The pin 10 is an integral part of the obstructing or closing element 15, and on the face of the obstructing or closing element 15 opposite the pin 10, there is an axial hole-like recess 16. The blocking or closing element 15 can be held and fixed by the pin 10 ′ or the negative mold 13 through the axial hole-shaped recess 16.

  In general, the blocking or closing element 15, sleeve 11, pin 10 can be used for all supports 5, 6, 9, ie any form of support. This is because the liquid supply path 7, the drainage path 8, and the intermediate drainage path 14 can be formed by drilling a post process.

  Although the shape of the cooling flow path 4 in the cast piston 2 is determined later, the casting core 3 is supported by the mold 1 at least at two positions facing each other for stability. In this case, for example, by disposing one support at a position that later becomes the liquid supply path 7, the liquid supply that later becomes the cooling flow path 4 through the contact surface of the support with the casting core 3. An opening has already been formed.

  The liquid supply path 7 and the drainage path 8 in the cooling flow path 4 described above are disposed adjacent to the same side of the piston 2 in order to obtain a good cooling effect. This is because the cooling fluid needs to flow through the entire cooling flow path 4.

  Therefore, for stability reasons, it is not sufficient to provide a single support for the liquid supply path 7 and the liquid discharge path 8. A support is also required at a position substantially opposite to the liquid supply path 7 or the drainage path 8 with respect to the longitudinal axis of the piston.

  The support 9 is formed with an undesired additional opening serving as the cooling flow path 4 (intermediate drainage path 14), and this opening drains oil before the actual drainage path 8. In order to close or reduce this additional opening, a blocking or closing element 15 is cast between the casting core 3 and the support 9.

  The blocking or closing element 15 further comprises the function of fixing the casting core 3. The blocking or closing element 15 either completely closes the cooling flow path 4 or reduces cooling fluid outflow. The blocking or closing element 15 preferably has an outer shape that can be securely connected with the cast piston 2.

  According to the present invention, the piston 2 is manufactured as follows.

  First, a dismantleable substantially annular casting core 3 that forms the cooling channel 4 is supported on three supports 5, 6, 9 that support the casting core 3 during the casting process. The first two supports 5 and 6 are arranged adjacent to each other in the connection region with the casting core 3 that will later form the liquid supply path 7 and the drainage path 8 of the cooling flow path 4.

  Opposite sides of the liquid supply path 7 and the liquid discharge path 8 in the casting core 3 are supported by a third support 9. The blocking or closing element 15 is provided at the connection between the third support 9 and the casting core 3. After the casting process, at least part of the blocking or closing element 15 is firmly connected to the piston 2, and after the casting core 3 is removed, the connecting portion is closed or at least the flow path is narrowed. A path 14 is formed.

  The blocking or closing element 15 comprises a pin 10 that enters the casting core 3, and the sleeve 11 is attached to this pin 10. In this case, the sleeve 11 is disposed between the casting core 3 and a negative mold 13 such as a metal mold, and the pin 10 enters both the casting core 3 and the negative mold 13. Thus, the casting core 3 and the negative mold 13 can be fixed to each other (see FIGS. 3, 4, 5, and 6).

  The piston 2 is cast using this mold 1 and, after cooling, the casting core that forms the cooling flow path 4 is removed (in detail, it is washed away). In this process, the pin 10 is also pulled out of the sleeve 11, so that only the sleeve 11 remains in the cast piston 2.

  In this case, the sleeve 11 can be fixed in the piston 2 via an appropriate convex portion, concave portion, or circumferential groove 12 outside the sleeve 11. Depending on whether the obstruction or closure element 15 is designed as an obstruction element or as a closure element, it is possible to either prevent cooling fluid outflow or reduce cooling fluid outflow.

  In particular, the third support of the casting core 3 according to the invention makes it possible to form a particularly stable mold 1 from the position of the intermediate drainage path 14 in the cooling channel 4 by means of the blocking or closing element 15. A large amount of unintentional refrigerant can be prevented from flowing out.

Claims (11)

A mold (1) for a piston (2) of an internal combustion engine,
A substantially annular casting core (3) that can be disassembled to form a cooling channel (4);
At least two supports (5, 6) for supporting said casting core (3) during the casting process;
With
At least one of the two supports (5, 6), or an additional third support (9) and a connection between the casting core (3), an obstruction or closure element (15) is arranged,
The blocking or closing element (15) is at least partially firmly connected to the piston (2) after the casting process and closes the connection after removal of the casting core (3), or at least A mold characterized by forming an intermediate drainage channel (14) with a narrowed channel. The mold according to claim 1,
The blocking or closing element (15) comprises a pin (10) that enters the casting core (3);
The sleeve (11) is attached to the pin (10), or
A mold having a bearing-like hole (16) on the opposite side of the pin (10). The mold according to claim 1 or 2,
The two supports (5, 6) are provided adjacent to each other, and later, at the connecting portion with the casting core (3), the liquid supply path (7) of the cooling channel (4) ) And drainage channel (8),
A third support (9) for supporting the casting core (3) is provided on the opposite side of the casting core (3) from the liquid supply path (7) and the drainage path (8). A mold characterized by being made. The mold according to claim 3, wherein
The liquid supply path (7), the drainage path (8), and / or the intermediate drainage path (14) are substantially different with a deviation of 5 ° or less from the annular surface of the casting core (3). A mold characterized by being oriented perpendicularly to each other. The mold according to any one of claims 2 to 4,
A mold characterized in that the blocking or closing element (15) or its sleeve (11) has an annular circumferential groove (12) on its outside. The mold according to any one of claims 2 to 5,
The sleeve (11) after casting is fixed to the piston (2), and the pin (10) is removable,
And / or
A mold characterized in that the blocking or closing element (15) comprises a pin formed integrally with the sleeve (11). The mold according to any one of claims 2 to 6,
A mold characterized in that the blocking or closing element (15) or its sleeve (11) has an outer diameter of about 4-5 mm and an inner diameter of about 1-2 mm. The mold according to any one of claims 1 to 7,
A mold characterized in that the piston (2) is made of a light metal alloy, in particular an aluminum alloy. The mold according to any one of claims 2 to 8,
The sleeve (11) is arranged between the casting core (3) and the negative mold (13), and the pin (10) is connected to the casting core (3) and the negative mold (13). ), The casting core (3) and the negative mold (13) are fixed to each other. The mold according to claim 9, wherein
A casting mold characterized in that the casting core (3) and / or the negative mold (13) is formed as a salt or sand core. A casting piston (2) for an internal combustion engine,
An annular cooling channel (4) located inside to cool the piston (2) during operation of the internal combustion engine;
Casting piston in which the cooling channel (4) is formed by the mold (1) according to any one of claims 1 to 10.

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