KR20090117056A - Crankshaft of forging and casting conjugation - Google Patents

Abstract

PURPOSE: A forged and cast crankshaft is provided to simplify the manufacturing process by selectively forging the part requiring durability against to an external force. CONSTITUTION: A forged and cast crankshaft comprises a crank journal(11), a crank pin(12), and a crank web(13). The crank journal is integrally forged to pass through the crank web. The crank web is cast to the crank journal to connect the crank journal and the crank pin. A pellet(21) is formed on the end of the crank journal or the crank pin to penetrate a specific part of the crank web.

Description

Crankshaft forged and cast bonded {CRANKSHAFT OF FORGING AND CASTING CONJUGATION}

The present invention relates to a crankshaft, and more particularly, to a crankshaft formed by casting a crank web to a forged crank pin and a crank journal.

In general, the crankshaft is supported by the journal bearing in the crank chamber to convert the linear movement of the piston obtained from the power stroke of each cylinder into the rotational movement to transmit the output of the engine to the outside.

In addition, the crankshaft for internal combustion engines is produced by integral forging or casting, and the crank web connecting the crank pin and the crank journal to the connecting end of the connecting rod, and the balance weight and shaft selectively installed on the opposite side of the crankshaft to maintain the balance of the crankshaft. It consists of parts, such as a crank journal to support.

In general, the crankshaft connected to the connecting rod is one of the components in which durability against friction, wear, flexural load, and torsional load is the most important factor among engine components.

Therefore, in order to manufacture a durable crankshaft, a method of forging the entire crankshaft is used, because mechanical properties such as tensile strength, yield strength, fatigue strength, and elongation of the material itself are superior to castings. It was because.

However, this has a problem that the forging process has a complicated and high production cost even to the crank web and the balance weight that do not receive relatively large external forces.

Accordingly, the present invention, the crank journal or the crank pin is forged integrally made of forged steel so as to penetrate adjacent crank web, the crank web formed of cast steel, cast iron or spherical graphite cast iron, etc. in the outside of the crank journal or crank pin The above problems have been overcome by melting and casting.

In addition, the present invention is cast-bonded dissimilar metals in the cooling process by arranging forging steel having a low coefficient of thermal expansion inside the cooling process and casting molten metal, such as cast steel, cast iron or spheroidal graphite cast iron, having a large coefficient of thermal expansion to the outside. The structure that the surface becomes more solid was made possible.

In order to solve the above problems, the present invention, forging a crank journal or a crank pin and casting-joining the crank web to select and strengthen the part requiring durability against external force, and internally forged steel with low shrinkage during cooling The present invention aims to obtain forged and cast-joined crankshafts characterized in that molten metals such as cast steel, cast iron, or spherical graphite cast iron are disposed outside to further strengthen the joint surface of dissimilar metals. .

In order to achieve the above technical problem, the present invention provides a forged and cast-bonded crankshaft.

The crankshaft in the present invention,

In a crankshaft consisting of a crank journal of a crankshaft for an internal combustion engine and a reciprocating air compressor, a crank pin and a crank web thereof,

The crank journal or crank pins are integrally forged to penetrate adjacent crank webs, and the crank webs are cast bonded to the crank journals or crank pins.

Meanwhile, at least one of the crank journal and the crank pin and the first hollow portion or the second hollow portion simultaneously passing through the crank web adjacent thereto may be formed.

Here, the first hollow portion refers to a hollow portion penetrating a crank journal and a crank web adjacent thereto. Meanwhile, the second hollow portion refers to a hollow portion penetrating through the crank pin and the crank web adjacent thereto.

According to the above configuration, by processing the crank journal and the crank pin for which the rotation moment is generated by the engine by forging, it is possible to prevent a decrease in the endurance life itself caused by the large acceleration and centrifugal force generated by the rotational weight.

On the other hand, by producing a relatively small force of the crank web by casting and joining the crank journal or crank pin, it is possible to increase the productivity and lower the manufacturing cost.

In addition, by using the principle that the shrinkage of liquid cast steel, cast iron or spherical graphite cast iron molten metal is greater than solid forging steel during cooling, the present invention provides a crank pin made of a forged steel is a crank web of molten metal during casting By being located outside of the crank journal, the dissimilar metal cast joint portion was formed to be more firmly bonded during the post-fusion welding at high temperature.

Meanwhile, the forged crank journal and the forged crank pin are forged steel and the crank web is characterized in that it is any one of cast steel, cast iron or spherical graphite cast iron.

On the other hand, wherein the forged crank journal or the forged crank pin,

Between the adjacent crank web and the crank web is made of a cylindrical constant diameter, but the inner radius of the crank web is characterized in that the outer radius gradually decreases toward the outside.

Furthermore, a fillet is formed at the distal end of the cylindrical outer circumferential surface of the crank journal to which the bearing is connected and the crank pin connected to the connecting rod to facilitate the rotational movement.

Furthermore, inside the crank web, the outer radius of the crank journal or crank pin is made smaller. By constructing as described above, it is possible to prevent waste that comes from forging unnecessary parts by the forging of the inner part of the crank web that is not subjected to a large external force than the cylindrical case.

According to the configuration as described above, the present invention by forging only the crank journal or crank pin portion of a simple shape without forging the entire crankshaft, and by forming a crankshaft by casting the crank web that is a connecting portion thereof, The parts requiring durability are forged by the forging process and the manufacturing process is simplified.

As a result, the present invention can increase the productivity and lower the manufacturing cost compared to the conventional forged crankshaft and there is an advantageous effect that the dissimilar metal bonding surface is more firmly combined.

Hereinafter, the configuration of the present invention according to the accompanying drawings in more detail. Here, the reference numerals attached to each drawing maintains consistency, and therefore, the same reference numerals should be interpreted as having the same configuration and operation in different drawings.

In addition, the crankshaft described below relates to the hollow crankshaft, and will be apparent to those skilled in the art.

1 is a perspective view of a forged and cast-joined hollow crankshaft showing a preferred embodiment of the present invention. It demonstrates concretely below.

In the present invention, the hollow crankshaft is a crank web (11) for connecting the crank pin (12) and the shaft supporting the crank journal (11), the crank pin (12) and the crank journal (11) connected to the large end of the connecting rod ( 13).

On the other hand, the first hollow portion 14 which penetrates the center of the crank journal 11 and the adjacent crank web 13 at the same time is formed, and simultaneously penetrates the center of the crank pin 12 and the adjacent crank web 13. The second hollow portion 15 is formed.

When manufactured in the hollow as described above it is known that the strength is about 1.5 to 2 times compared to the solid crankshaft.

Fig. 2 is a longitudinal sectional view of a forged and cast-joint hollow crankshaft showing a preferred embodiment of the present invention. It demonstrates concretely below.

The hatched portion in FIG. 2 is forged as the crank journal 11 and the crank pin 12. On the other hand, the crank web 13 constituting the rest except the hatched portion is cast-bonded to the crank journal 11 and the crank pin 12.

Meanwhile, in order to cast-cast the crank web 13 to the crank journal 11 or the crank pin 12, it is preferable to use a conventional dissimilar metal melt bonding method.

As described above, the crank journal 11 and the crank web 13 cast-joined with the forging are superior in productivity compared to the crankshaft manufactured only by forging, and have various effects such as cost reduction.

In addition, as the molten metal material of the crank web 13 used in the casting bonding as described above, various metal materials such as cast steel and cast iron may be used, but spherical graphite cast iron is particularly preferable. Here, nodular cast iron refers to cast iron that crystallizes nodular graphite while being usually cast.

On the other hand, the fillet 21 is formed in the distal end of the outer peripheral surface of the crank pin 12 to which the connecting rod is connected and the outer peripheral surface of the crank journal 11 to which the bearing is connected.

By forming the fillet 21 as described above, the crank pin 12 and the crank journal 11 are not easily damaged even when a load caused by excessive external force is applied.

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and various substitutions, additions, and changes are possible in the technical field to which the present invention pertains without departing from the technical spirit of the present invention. It will be clear to those of ordinary knowledge.

1 is a perspective view of a forged and cast-joined hollow crankshaft showing a preferred embodiment of the present invention.

Fig. 2 is a longitudinal sectional view of a forged and cast-joint hollow crankshaft showing a preferred embodiment of the present invention.

<Description of symbols for important parts of the drawings>

11: Crank Journal 12: Crank Pins

13: crank web 14: first hollow part

15: second hollow portion 21: fillet

Claims (8)

In a crankshaft consisting of a crank journal of a crankshaft for an internal combustion engine and a reciprocating air compressor, a crank pin and a crank web thereof, A forged and cast joined crankshaft, characterized in that the crank journal (11) is integrally forged to penetrate the crank web (13), and the crank web (13) is cast bonded to the crank journal (11). In a crankshaft consisting of a crank journal of a crankshaft for an internal combustion engine and a reciprocating air compressor, a crank pin and a crank web thereof, A forged and cast-joined crankshaft, characterized in that the crank pin (12) is integrally forged to penetrate the crank web (13), and the crank web (13) is cast-joined with the crank pin. The method of claim 1, The forged crank journal 11, Forged and cast-joined, characterized in that the diameter between the adjacent crank web 13 and the crank web 13 is of a constant cylindrical shape and the outer diameter gradually decreases toward the outside in the interior passing through the crank web 13 Crankshaft. The method of claim 2, The forged crank pin 12, Forged and cast-joined, characterized in that the diameter between the adjacent crank web 13 and the crank web 13 is of a constant cylindrical shape and the outer diameter gradually decreases toward the outside in the interior passing through the crank web 13 Crankshaft.    The method according to claim 1 or 3, The forged and cast joined crankshaft, characterized in that the forged crank journal (11) is forged steel, the crank web (13) is any one of cast steel, cast iron or nodular cast iron. The method according to claim 2 or 4, The forged and cast joined crankshaft, characterized in that the forged crank pin (12) is forged steel and the crank web (13) is any one of cast steel, cast iron or nodular cast iron. The method according to any one of claims 1 to 4, One of the crank journal 11 and the crank pin 12 is forged and cast joint, characterized in that the distal end of the cylindrical outer peripheral surface forms a fillet 21, and penetrates a portion of the adjacent crank web 13 Crankshaft. The method according to any one of claims 1 to 4, Forged and cast-joined crankshafts, characterized in that hollow portions 14, 15 are formed at the same time through at least one of the crank journal 11 and the crank pins 12 and the crank web 13 adjacent thereto. .

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