JP6550919B2 - Forging crankshaft manufacturing equipment - Google Patents

Description

  The present invention relates to an apparatus for manufacturing a crankshaft by hot forging.

  In reciprocating engines such as automobiles, motorcycles, agricultural machines, ships, etc., a crankshaft is indispensable in order to convert the reciprocating motion of the piston into rotational motion and extract power. The crankshaft can be manufactured by die forging or casting. In particular, when high strength and high rigidity are required for the crankshaft, forged crankshafts manufactured by forging are frequently used because of excellent characteristics.

  Generally, for production of forged crankshafts, a billet is used as a raw material, and the billet has a round or square cross section and a constant cross sectional area over the entire length. The manufacturing process of a forged crankshaft includes each process of preforming, die forging, deburring, and shaping. Usually, the preforming process includes the steps of roll forming and bending, and the die forging process includes the steps of roughing and finishing.

  FIGS. 1A to 1F are schematic views for explaining a manufacturing process of a conventional general forged crankshaft. FIG. 1A shows a billet, FIG. 1B shows a roll waste, FIG. 1C shows a bending waste, FIG. 1D shows a rough forged material, FIG. 1E shows a finished forged material, and FIG. 1F shows a forged crankshaft.

  The crankshaft 1 illustrated in FIG. 1F includes five journal portions J1 to J5, four pin portions P1 to P4, a front portion Fr, a flange portion Fl, and eight crank arm portions (hereinafter simply referred to as “arm portions”). It is also composed of A1 to A8. The arm parts A1 to A8 connect the journal parts J1 to J5 and the pin parts P1 to P4, respectively. The crankshaft 1 has counterweight portions (hereinafter also simply referred to as “weight portions”) W1 to W8 in all eight arm portions A1 to A8. Such a crankshaft 1 is mounted on a four-cylinder engine and is a four-cylinder eight-piece counterweight.

  The four pin portions P1 to P4 are all eccentric with respect to the journal portions J1 to J5. The phases of the pin portions P1 to P4 are appropriately set so as to be plane-symmetrical about the central journal portion J3 in the longitudinal direction of the crankshaft 1. Therefore, the arm portions (A4, A5) connected to the central journal portion J3 are plane-symmetrical about the journal portion J3. That is, the two arm portions (A4, A5) are both connected to the same journal portion J3 and to the pin portions (P2, P3) having the same phase.

  Hereinafter, when the journal portions J1 to J5, the pin portions P1 to P4, the arm portions A1 to A8, and the weight portions W1 to W8 are collectively referred to, the reference numerals are “J” for the journal portion and “P” for the pin portion. Also, “A” for the arm portion and “W” for the weight portion. The pin portion P and a pair of arm portions A (including the weight portion W) connected to the pin portion P are collectively referred to as "slow".

  In the manufacturing method shown in FIG. 1, the forged crankshaft 1 is manufactured as follows. First, after the billet 2 shown in FIG. 1A is heated by a heating furnace (for example, an induction heating furnace or a gas atmosphere heating furnace), roll forming is performed. In the roll forming step, for example, the billet 2 is rolled by a hole-shaped roll and squeezed while its volume is distributed in the longitudinal direction to form a roll stock 3 as an intermediate material (see FIG. 1B). Next, in the bending hitting process, the roll wasteland 3 is partially pressed down from the direction perpendicular to the longitudinal direction to distribute the volume, and the bending wasteland 4 as a further intermediate material is formed (see FIG. 1C).

  Subsequently, in the roughing process, the bent rough ground 4 is press-forged using a pair of upper and lower dies to form a rough forged material 5 in which the approximate shape of the crankshaft (final product) is formed (see FIG. 1D). ). Further, in the finish punching process, the rough forging material 5 is press-forged using a pair of upper and lower dies, and the finished forging material 6 shaped to match the crankshaft of the final product is formed (see FIG. 1E). . At the time of roughing and finishing, surplus material flows out as burrs from between the split surfaces of the molds facing each other. For this reason, the rough forgings 5 and the finish forgings 6 both have a large amount of burrs (5a, 6a) around them.

  In the deburring step, for example, while the finish forged material 6 with the burrs 6a obtained by finish punching is sandwiched between the mold from above and below and held, the burrs 6a are punched out and removed by the blade type. Thereby, a burrless forged material having substantially the same shape as the forged crankshaft 1 shown in FIG. 1F can be obtained. In the shaping process, a key portion of the burr-free forging material is pressed slightly from above and below with a die to correct it into the dimensional shape of the final product. Here, the essential parts of the burr-free forging material correspond to, for example, the shaft portion such as the journal portion J, the pin portion P, the front portion Fr, the flange portion Fl, and the arm portion A and the weight portion W. Thus, the forged crankshaft 1 is manufactured.

  The manufacturing process shown to FIG. 1A-1F is applicable not only to the crankshaft of 4 cylinder-8 piece counterweight shown to FIG. 1F but to various crankshafts. For example, the present invention can also be applied to a crankshaft in which the weight portion W is provided to a part of the arm portions A, more specifically, to a crankshaft of a four-cylinder four-piece counterweight. In the crankshaft of the four-cylinder / four-counterweight, for example, the first first arm part A1, the last eighth arm part A8, and the central two arm parts (fourth arm part A4, fifth arm) Weight portions (W1, W4, W5, W8) are integrally provided in the portion A5). Further, the remaining arm portions, specifically, the second, third, sixth and seventh arm portions (A2, A3, A6, A7) do not have weight portions, and the shape is oval Become. Hereinafter, an arm portion having a weight portion integrally is referred to as a "weighted arm portion", and an arm portion not having a weight portion is also referred to as a "weightless arm portion".

  The manufacturing process shown in FIGS. 1A to 1F can also be applied to a crankshaft mounted on a three-cylinder engine, an in-line six-cylinder engine, a V-type six-cylinder engine, an eight-cylinder engine or the like. In addition, when adjustment of the arrangement | positioning angle of a pin part is required, a twisting process is added after a burr removal process.

  By the way, in recent years, reciprocating engines for automobiles in particular have been required to be reduced in weight in order to improve fuel efficiency. For this reason, the demand for weight reduction is also increasing for crankshafts mounted on reciprocating engines. As conventional techniques for reducing the weight of the forged crankshaft, there are the following.

  Patent Documents 1 and 2 describe an arm part in which a hole is formed on the surface on the journal part side, and also describe a method of manufacturing a crankshaft having this arm part. The hole portion of the arm portion is formed on a straight line connecting the shaft center of the journal portion and the shaft center of the pin portion (hereinafter, also referred to as "arm portion center line") and deeply recessed toward the pin portion. In such an arm described in the same document, the volume integration of the hole is reduced. The weight reduction of the arm portion leads to the weight reduction of the weight portion paired with the arm portion, and hence leads to the weight reduction of the entire forged crankshaft. Further, since the arm portion disclosed in the same document is maintained thick at both side portions in the vicinity of the pin portion sandwiching the arm portion center line, rigidity (torsional rigidity and bending rigidity) is also ensured.

  Thus, if the surface of the arm portion on the journal portion side is provided with a dent while maintaining a large thickness at both sides near the pin portion of the arm portion, it is possible to simultaneously achieve weight reduction and rigidity.

  However, forged crankshafts having such uniquely shaped arms are difficult to manufacture by conventional manufacturing methods. In the die forging process, if a dent is to be formed on the surface of the arm portion, the die drawing gradient of the die at the dent portion becomes a reverse gradient, and there is a situation in which the molded forging material cannot be removed from the die. .

  In order to cope with such a situation, in the manufacturing method described in Patent Literatures 1 and 2, in the die forging step, the arm portion is formed to be small without forming a recess in the surface on the journal portion side of the arm portion. In addition, after the deburring process, a punch is pushed into the surface of the arm portion on the side of the journal portion, and a dent is formed by the trace of the punch.

JP 2012-7726 A JP, 2010-230027, A

  Certainly, according to the manufacturing methods described in Patent Documents 1 and 2, a recess is formed on the surface of the arm portion on the journal portion side while maintaining a large thickness on both sides in the vicinity of the pin portion of the arm portion. Is possible. As a result, it is possible to manufacture a forged crankshaft that is designed to simultaneously achieve weight reduction and rigidity.

  However, in this manufacturing method, in order to form a dent on the surface of the arm portion on the journal portion side, the punch is strongly pressed into the surface of the arm portion to deform the entire arm portion, so that a great force is required for pushing the punch. . For this reason, a special equipment configuration is required to apply a great deal of force to the punch, and consideration must be given to the durability of the punch. In addition, further weight reduction is required while securing rigidity.

  An object of the present invention is to provide a forged crankshaft manufacturing apparatus capable of easily obtaining a forged crankshaft that simultaneously achieves weight reduction and rigidity securing.

  A manufacturing apparatus of a forged crankshaft according to an embodiment of the present invention includes: a journal portion serving as a rotation center; a pin portion eccentric to the journal portion; and a crank arm portion connecting the journal portion and the pin portion In the manufacturing process of the forged crankshaft which it has, it is a manufacturing apparatus of the forged crankshaft which performs shaping which corrects the shape of the forging material without burrs in which the shape of the said forged crankshaft was modeled. The crank arm portion of the forged crankshaft is an arm portion with a weight, all or part of which is integrally formed with a counterweight portion, and the forged material is formed on each of both side portions in the vicinity of the journal portion in the arm portion with the weight. And a first surplus portion protruding from the outer periphery.

  The apparatus for manufacturing a forged crank shaft is a pair of upper and lower parts that performs processing to deform the first excess thickness part and increase the thickness of the both sides in the vicinity of the journal part in the arm with weight together with the shaping process. And a first portion of the surface of the arm portion with weight that is pressed against a surface excluding at least the regions of the both side portions in the vicinity of the journal portion. A tool. The mold and the first tool each have a first guiding surface for guiding the first tool from the retracted position to the pressing position, and the first tool has one or both of the upper surface and the lower surface. And the first guiding surface is provided.

  The apparatus for manufacturing a forged crankshaft further includes a first jig movable along an eccentric direction of the pin portion, and the first jig guides the first tool with the first guide by the first guide surface. It is preferable that the first tool is held so as to be swingable in a first swing direction having an angle and a direction, and the first tool moves along the first guiding direction along with the movement of the first jig. In this case, the first jig holds the two first tools so as to be swingable in the first swinging direction, and the two first tools are the same in the crank arm portion. It is preferable that the two arm portions with weights connected to the pin portion are pressed against the surface on the pin portion side.

  The forging material further has a second excess thickness portion protruding from the outer periphery on each outer periphery of both side portions near the pin portion of the crank arm portion, and the mold deforms the second excess thickness portion It is preferable to further process to increase the thickness on both sides in the vicinity of the pin portion of the crank arm portion. In this case, the apparatus for manufacturing the forged crankshaft is accommodated in the open part of the mold, and the surface of the crank arm part on the side of the journal part excluding at least the area of the both sides in the vicinity of the pin part. The mold and the second tool each have a second guide surface for guiding the second tool from the retracted position to the pressed position, and the second tool includes Preferably, the second guide surface is provided on one or both of the upper surface and the lower surface.

  The manufacturing apparatus of the crankshaft further includes a second jig movable along the eccentric direction of the pin portion, and the second jig guides the second tool in a second guiding direction by the second guiding surface. It is preferable that the second tool be held so as to be able to swing in a second swing direction having an angle, and that the second tool move along the second guiding direction along with the movement of the second jig. In this case, the second jig holds the two second tools so as to be swingable in the second swinging direction, and the two second tools are the same in the crank arm portion. It is preferable that the two crank arm portions connected to the journal portion and connected to the pin portion having the same phase are respectively pressed against the surface on the journal portion side.

  The apparatus for manufacturing a forged crankshaft according to the present invention performs shaping by using a pair of molds at the top and bottom and deforms the first excess thickness in the weighted arm to increase the thickness of both sides in the vicinity of the journal. Apply. In that case, a 1st tool is pressed against the pin part side surface of an arm part with a weight, and the 1st tool is provided with a guide surface in any one or both of an upper surface and a lower surface.

  Such a manufacturing apparatus for a forged crankshaft according to the present invention can easily obtain a forged crankshaft in which the reduction in weight and the securing of rigidity are simultaneously achieved because the first surplus thickness portion is deformed by a mold. Moreover, the shape of the pin part side surface of the arm part with a weight can be shape | molded precisely by pressing of a 1st tool. Since the guide surface is provided on one or both of the upper surface and the lower surface of the first tool, the first tool can be prevented from interfering with the first jig and the mold, and the movable range of the first tool can be sufficiently secured. . Therefore, the forging material can be carried in and out smoothly.

FIG. 1A is a schematic view showing a billet in a manufacturing process of a conventional forged crankshaft. FIG. 1B shows a roll waste in the manufacturing process of a conventional forged crankshaft. FIG. 1C shows a bending stock in the manufacturing process of a conventional forged crankshaft. FIG. 1D shows a rough forged material in a conventional forged crankshaft manufacturing process. FIG. 1E shows a finish forged material in a conventional forged crankshaft manufacturing process. FIG. 1F shows a forged crankshaft in the process of manufacturing a conventional forged crankshaft. FIG. 2A is a perspective view schematically showing an example of the shape of the pin portion side surface of the weight-equipped arm portion of the shaped crankshaft which can be employed in the present invention. FIG. 2B is a diagram illustrating a pin portion side surface of the arm portion of FIG. 2A. FIG. 2C is a diagram illustrating a side surface of the arm portion of FIG. 2A. FIG. 2D is a cross-sectional view taken along the line AA of FIG. 2A. FIG. 3A is a perspective view schematically showing an example of the shape of the surface on the journal portion side of a suitable arm portion, which is suitable for the crankshaft after shaping which can be employed in the present invention. FIG. 3B is a view showing a surface on the journal side of the arm of FIG. 3A. FIG. 3C is a cross-sectional view taken along line B-B of FIG. 3A. FIG. 4A is a schematic view for showing an example of the shape of the surface on the pin portion side of the weight-equipped arm portion before shaping, and shows the surface on the pin portion side. FIG. 4B is a diagram illustrating a side surface of the arm portion of FIG. 4A. FIG. 4C is a cross-sectional view taken along line C-C of FIG. 4A. FIG. 5A is a schematic view for showing an example of the shape of the surface on the side of the journal with respect to the arm before shaping, and shows the surface on the side of the journal. 5B is a cross-sectional view taken along the line DD of FIG. 5A. FIG. 6A is a perspective view schematically showing a configuration example of a forged crankshaft manufacturing apparatus according to the present invention. FIG. 6B is a top view of FIG. 6A and shows the case of the pressing position. FIG. 6C is a top view of FIG. 6A and shows the case of the retracted position. FIG. 6D is an enlarged perspective view showing the main part of FIG. 6A. FIG. 7A is a perspective view schematically showing a configuration example of the second tool. FIG. 7B is an enlarged perspective view showing the main part of FIG. 7A. FIG. 7C is a top view of FIG. 7A and shows the case of the pressing position. FIG. 7D is a top view of FIG. 7A and shows the case of the retracted position.

  Below, the manufacturing apparatus of the forged crankshaft of this embodiment is demonstrated, referring drawings.

1. Shape of Crankshaft A forged crankshaft targeted by the present embodiment includes a journal portion serving as a rotation center, a pin portion that is eccentric with respect to the journal portion, and an arm portion that connects the journal portion and the pin portion. Further, the forged crankshaft has a weight portion integrally with all or a part of the arm portions. As such a forged crankshaft, the forged crankshaft shown in FIGS. 2A to 2D and FIGS. 3A to 3C can be employed, for example.

  2A to 2D are schematic diagrams showing examples of the shape of the surface on the pin side of the arm portion with weight for a crankshaft (final product) after shaping that can be employed in the present invention. Among them, FIG. 2A is a perspective view, FIG. 2B is a view showing a surface on a pin portion side, FIG. 2C is a view showing a side surface, and FIG. In FIGS. 2A-2D, one of the weighted arm portions of the crankshaft is representatively extracted and shown, and the remaining arm portions are omitted. Further, FIG. 2C is a projection view from the direction shown by the dashed arrow in FIG. 2B.

  The weighted arm portion A has a recess in the inner region At of both side portions (Ac, Ad) near the journal portion J in the surface on the pin portion P side. Further, both side portions (Ac, Ad) in the vicinity of the journal portion J bulge toward the pin portion P, and the thickness of the both side portions (Ac, Ad) is thicker than the thickness of the recess. Here, the side portion means the side surface of the arm portion A in the width direction (direction perpendicular to the eccentric direction of the pin portion) and the peripheral portion thereof, in other words, the end portion in the width direction of the arm portion A .

  In such an arm portion A, the thickness of both side portions (Ac, Ad) in the vicinity of the journal portion J is maintained thick, and a recess is formed on the surface on the pin portion P side. For this reason, weight reduction can be achieved by the depression of the surface of the arm portion A on the side of the pin portion P. In addition, by maintaining the thickness of both sides (Ac, Ad) in the vicinity of the journal portion J of the arm portion A, it is possible to secure rigidity.

  Subsequently, with respect to the shape of the surface of the arm portion A on the side of the journal portion J, a preferable aspect thereof will be described.

  3A to 3C are schematic views showing an example of the shape of the surface on the side of the journal of a suitable arm with respect to the crankshaft after shaping which can be adopted in the present invention, FIG. 3A is a perspective view, and FIG. 3B is the journal side. The figure which shows the surface and FIG. 3C are BB sectional drawings.

  Regardless of the presence or absence of the weight portion W, the arm portion A preferably has a dent in the region As inside the both side portions (Aa, Ab) near the pin portion P on the surface on the journal portion J side. Further, both side portions (Aa, Ab) in the vicinity of the pin portion P swell toward the journal portion J, and the thicknesses of both side portions (Aa, Ab) are preferably thicker than the thickness of the recess.

  In such an arm portion A, the thickness of both side portions (Aa, Ab) in the vicinity of the pin portion P is maintained thick, and a recess is formed on the surface on the journal portion J side. For this reason, while maintaining rigidity by maintaining the thickness of both sides (Aa, Ab) in the vicinity of the pin portion P, further weight reduction can be achieved by the depression on the surface of the journal portion J side.

  Then, the shape of the arm part before shaping is demonstrated, referring drawings.

  4A to 4C are schematic views showing an example of the shape of the surface on the side of the pin with respect to the arm with a weight before shaping, FIG. 4A is a view showing the surface on the side of the pin, FIG. FIG. In the figure, only one arm portion having an integral weight portion is extracted from the arm portions of the crankshaft, and the remaining crankshaft arm portions are omitted. FIG. 4B is a projection view from the direction indicated by the broken line arrow in FIG. 4A.

  Before shaping, the weighted arm portion A has a recess that matches the shape after shaping in the inner region At of both side portions (Ac, Ad) near the journal portion J on the surface on the pin portion P side. The recess smoothly extends to the area on both sides (Ac, Ad) near the journal J. Thereby, the thickness of the both sides (Ac, Ad) of the journal part J vicinity is thinner than the thickness after shaping.

  In addition, the arm portion A with a weight has first surplus portions (Aca, Ada) on the outer periphery of both side portions (Ac, Ad) in the vicinity of the journal portion J. The first surplus portion (Aca, Ada) protrudes from the outer periphery of both side portions (Ac, Ad). The 1st surplus part (Aca, Ada) shown to the same figure is plate shape, and it is provided along the outer periphery of the both sides (Ac, Ad) of the journal part J vicinity. The thickness of the first surplus portion (Aca, Ada) is comparable to or thinner than the thickness of both sides (Ac, Ad) of the root.

  The arm portion with weight before shaping in such a shape does not have a reverse gradient in any of the portion corresponding to the dent on the surface of the pin portion P side and the portion corresponding to the first surplus portion (Aca, Ada).

  5A and 5B are schematic views showing examples of the shape of the journal portion side surface of the arm portion before shaping, FIG. 5A is a view showing the journal portion side surface, and FIG. 5B is a DD cross-sectional view.

  The arm portion A after shaping shown in FIGS. 3A to 3D maintains the thickness of both side portions (Aa, Ab) in the vicinity of the pin portion P without depending on the presence or absence of the weight portion, and the journal portion J side. A recess is formed on the surface of the. In such a case, the arm part A before shaping matches the shape after shaping (final product) in the inner region of both side parts (Aa, Ab) near the pin part P on the surface on the journal part J side. It is preferable to have a dent. The recess smoothly extends to the area of both sides (Aa, Ab) near the pin portion P. Thereby, the thickness of the both side parts (Aa, Ab) in the vicinity of the pin part P before shaping is thinner than the thickness after shaping.

  In addition, it is preferable to provide a second surplus portion (Aaa, Aba) on the outer periphery of both sides (Aa, Ab) in the vicinity of the pin portion P, and the second surplus portion (Aaa, Aba) It protrudes from the outer periphery of (Aa, Ab). The second surplus portion (Aaa, Aba) shown in the figure is plate-shaped and is provided along the outer periphery of both side portions (Aa, Ab) in the vicinity of the pin portion P. The thickness of the second surplus portion (Aaa, Aba) is comparable to or thinner than the thickness of both sides (Aa, Ab) of its root.

  The pre-shaping arm portion having such a shape does not have a reverse gradient at any of the portion corresponding to the dent on the surface of the journal portion J and the portion corresponding to the second surplus portion (Aaa, Aba).

2. 6A to 6D are schematic views showing a configuration example of a forged crankshaft manufacturing apparatus according to the present invention, FIG. 6A is a perspective view, and FIG. 6B is a top view in a pressing position. 6C is a top view in the case of the retracted position, and FIG. 6D is an enlarged perspective view of the main part. 6A to 6D show the burr-free forging material 91, the bottom side member 11 that constitutes a part of the lower die of the mold, the first tool 20, and the first jig 30. FIG. In FIG. 6A, the top side member 12 which comprises a part of lower mold, the 2nd tool 40, and the 2nd jig 50 are further shown. 6B and 6C, the burr-free forging material 91 is shown by an imaginary line.

  6A to 6C, among the forged material 91 without burr, one pin portion P, two weighted arm portions A connected to the pin portion P, and a journal portion J connected to the two weighted arm portions A A part of is extracted and shown. In FIG. 6D, compared to FIGS. 6A to 6C, a part of the burr-free forging material 91 is omitted. Moreover, in FIG. 6A-6D, two 1st tools 20 are shown among several 1st tools with which a manufacturing apparatus is provided, and illustration of another 1st tool is abbreviate | omitted. The two first tools are pressed against the pin P side surfaces of the two weighted arm parts A connected to the same pin part P, respectively.

  The first tool 20 is pressed against the surface excluding at least the regions on both sides in the vicinity of the journal portion J in the surface on the pin portion P side of the arm portion A with weight. For example, the tip end surface 20a of the first tool 20 is pressed against the inner region At of both side portions (Aa, Ab) near the journal portion J in the surface of the arm portion A on the pin portion P side.

  The pair of upper and lower molds can be composed of an upper mold and a lower mold. In the figure, for easy understanding of the drawing, the upper mold is not shown and only some members constituting the lower mold are shown.

  In the upper mold and the lower mold, mold engravings 11a are engraved respectively in order to deform the protruding excess thickness portions together with shaping processing for correcting the shape of the forged material without burrs. The mold engraving portion 11a of the bottom-side member 11 constituting the lower mold of the drawing constitutes a part of the lower mold engraving portion.

  The upper and lower mold engraving portions reflect the shape of a portion of the shape of the crankshaft (final product) excluding a part. Specifically, in order to accommodate the first tool 20, a tool opening is provided in the mold (upper mold and lower mold). For this reason, the concave shape on the pin portion side surface of the arm portion is not reflected in the mold engraving portion.

  Moreover, when forming a dent in the journal part side surface of an arm part (refer said 3A-3C), the concave shape in the journal part side surface of an arm part is not reflected by a type | mold engraving part. This is because when this concave shape is reflected in the mold engraving portion, a part of the mold engraving portion has an inverse gradient. In this case, in order to accommodate the second tool 40, a tool opening may be provided in the mold (upper mold and lower mold).

  In order to accommodate the first jig 30, the mold (upper mold and lower mold) is provided with a groove-like jig opening portion 11c (see FIG. 6B).

  In order to guide the first tool 20 from the retracted position to the pressing position, both the upper surface 20b and the lower surface 20c of the first tool 20 are convex extending along the first guiding direction (see solid arrows in FIGS. 6B and 6C) A portion 20d is provided. Moreover, in order to receive the convex part 20d of the 1st tool 20, the groove-shaped recessed part 11d is provided in the bottom face of the tool opening part of the bottom side member 11 which comprises a metal mold | die (refer FIG. 6D). Therefore, when the first tool 20 moves from the retracted position to the pressing position, the first tool 20 is moved along the side surfaces 20e of the concave portion 11d of the tool opening portion (mold) and the side surface 20e of the convex portion 20d of the first tool 20. One tool 20 moves. That is, both side surfaces 20d of the convex portions provided on the upper surface 20b and the lower surface 20c of the first tool 20 function as guide surfaces (first guide surfaces) together with both side surfaces of the recess 11d of the tool opening (mold). .

  Such a forged crankshaft manufacturing apparatus according to the present embodiment uses a pair of upper and lower dies to shape and process the thickness of both side portions near the journal portion by deforming the first surplus portion in the weighted arm portion. To increase the processing. For this reason, in the weighted arm portion of the obtained crankshaft, the pin portion side surface can be made concave while maintaining the thickness of both side portions in the vicinity of the journal portion thick. Therefore, it is possible to reduce the weight and secure the rigidity at the same time.

  In the process of deforming the first excess thickness portion to increase the thickness of both sides in the vicinity of the journal portion, the first excess thickness portion may be bent toward the surface of the pin portion with a die. In addition, the first excess thickness portion may be crushed by a mold and may be protruded to the pin portion side. For this reason, the manufacturing apparatus for a forged crankshaft according to the present embodiment can easily obtain a crankshaft achieving both weight reduction and securing rigidity simultaneously without requiring a large amount of force.

  When deforming the first excess thickness portion, the first tool is pressed against the pin portion side surface of the weight-equipped arm portion, so that a dent or the like on the surface of the pin portion side is held. As a result, the shape can be precisely formed on the surface on the pin portion side, specifically, on both sides in the vicinity of the journal portion and the inner region thereof. Thus, the 1st tool aims at the holding | maintenance by pressing, and is not pushed into the pin part side surface of an arm part. For this reason, the force required to press the first tool is small.

  Moreover, the manufacturing apparatus of the forged crankshaft of this embodiment provides a 1st guide surface in any one or both of the upper surface 20b of the 1st tool 20, and the lower surface 20c. For this reason, it is not necessary to make the side shape of the first tool 20 flat, and for example, the shape can be appropriately changed by chamfering or rounding. Thereby, the width of the first tool 20 can be reduced, so that the first tool 20 can be prevented from interfering with the first jig 30 or the mold, and the movable range of the first tool 20 can be sufficiently secured. Therefore, the forging material can be carried in and out smoothly.

  The forged crankshaft manufacturing apparatus of the present invention is not limited to the case where the forged crankshaft is pressed against the surfaces of the two weighted arm portions A connected to the same pin portion P as shown in FIG. 6A. For example, one of two arm portions connected to the same pin portion P is an arm portion without weight, and the first tool can be applied only to the surface of the other arm portion A with weight A on the pin portion P side. In this case, one first tool is disposed between two arm portions connected to the same pin portion P, and the first jig is configured to hold the one first tool.

  In the case where two arm parts A connected to the same pin part P integrally have a weight part W, the two first tools 20 interfere with each other, and the movable range of the first tools 20 tends to be insufficient. In order to prevent this and sufficiently secure the movable range of the first tool 20, the two first tools 20 pressed against the surface of the pin part P side of the two weighted arm parts A connected to the same pin part P, respectively. Preferably, the first guide surface 20e is provided on one or both of the upper surface 20b and the lower surface 20c.

  Here, unlike the configuration shown in FIGS. 6A to 6D, the first tool 20 is fixed to the first jig 30, and the first tool is moved along the first guiding direction according to the movement of the first jig. It can also be configured to move. However, in the above configuration, since the first guiding directions are different among the plurality of first tools 20, the directions in which the first jig 30 is moved are also different. For this reason, there is a possibility that the movable range becomes insufficient due to interference between the first jig 30 and the driving device (not shown).

  From the viewpoint of preventing interference between the first jig 30 and the driving device (not shown) and unifying the direction in which the first jig 30 is moved, the eccentric direction of the pin portion (hatching in FIGS. 6B and 6C is performed). It is preferable to include a first jig 30 that is movable along the arrows). In this case, the first jig 30 holds the first tool 20 so as to be able to swing in the first swing direction (see the broken line arrows in FIGS. 6B and 6C) having an angle with the first guide direction by the first guide surface. .

  If such a first jig 30 is provided, the first tool 20 can be moved along the first guiding direction by moving the first jig along the eccentric direction. For this reason, it can arrange | position between an arm part and the arm part next to it, preventing interference with a forging material. Further, since the first jig 30 moves along the eccentric direction, the mechanism for driving the movement of the first jig 30 can be made common, and the equipment configuration of the manufacturing apparatus can be simplified. As a result, the first tool 20 can be disposed in a narrower space while securing the movable range of the first tool. The first swinging direction can be appropriately set according to the first guiding direction.

  When the two first tools 20 are pressed against the surface of the pin part P side of the two weighted arm parts A connected to the same pin part P, the two first tools 20 are moved by a single first jig 30. It is preferable to hold them swingably, respectively. Also by this, the configuration of the manufacturing apparatus can be simplified, and the movable range of the first tool 20 can be more sufficiently secured.

  The forging material 91 preferably has a second surplus portion (Aaa, Aba) as shown in FIGS. 5A and 5B. In this case, the mold deforms the second surplus portion (Aaa, Aba) in addition to shaping and deforming the first surplus portion (Aca, Ada), and both sides of the arm portion near the pin portion It is preferable to further apply processing to increase the thickness. As a result, in the obtained forged crankshaft, as shown in FIGS. 3A to 3C, the weight can be further reduced while securing the rigidity.

  In the processing of deforming the second excess thickness portion to increase the thickness of both sides in the vicinity of the pin portion, the second excess thickness portion may be bent toward the surface of the journal portion side by a die. Further, the second surplus portion may be crushed by a mold and protruded to the journal portion side. As a result, it is possible to easily obtain a crankshaft that achieves weight reduction and securing rigidity simultaneously without requiring a great deal of force.

  When the forged material has the second surplus portion, the forged crankshaft manufacturing apparatus of the present embodiment preferably includes the second tool 40 pressed against the surface of the arm portion on the journal portion side.

  7A to 7D are schematic views showing a configuration example of the second tool, FIG. 7A is a perspective view, FIG. 7B is a perspective view showing an enlarged main part, and FIG. 7C is a top view showing a pressing position. FIG. 7D is a top view showing the case of the retracted position. FIGS. 7A to 7D show the top side member 12 constituting a part of the lower mold of the mold, the second tool 40, and the second jig 50. Moreover, in FIG. 7A, a part of burr-free forging material 91 of a to-be-processed material is shown. About the above-mentioned 1st tool 20, illustration is omitted.

  The second tool 40 is pressed against the surface on the journal side of the arm except at least the area on both sides near the pin. For example, the tip surface 40a of the second tool 40 is pressed against the region As inside the both side portions (Aa, Ab) in the vicinity of the pin portion P in the surface on the journal portion J side of the arm portion A (FIG. 5A and FIG. 5B).

  In order to accommodate the second tool 40, a tool opening 12b is provided in the mold (upper mold and lower mold). Further, in order to accommodate the second jig 50, groove-shaped jig opening portions 12c are provided in the mold (upper mold and lower mold), respectively.

  In order to guide the second tool 40 from the retracted position to the pressing position, the second guide direction (FIGS. 7C and 7D) is respectively provided on the upper surface 40b and the lower surface of the second tool 40 shown in the same figure as the first tool. A convex portion 40d extending along the solid line arrow) is provided. Moreover, in order to receive the convex part 40d of the 2nd tool 40, the groove-shaped recessed part 12d is provided in the top side member 12 which comprises a metal mold | die. For this reason, when the second tool 40 moves from the retracted position to the pressing position, it is applied to both side surfaces of the concave portion 12d of the top side member 12 constituting the mold and both side surfaces 40e of the convex portion 40d of the second tool 40. The second tool 40 moves along. That is, the side surfaces 40e of the convex portion 40d provided on the upper surface 40b and the lower surface of the second tool 40 function as guide surfaces (second guide surface) together with the side surfaces of the recess 12d of the top side member 12 constituting the mold. To do.

  If such a second tool 40 is provided, the depression on the journal side surface is held by the pressing of the second tool. Therefore, the shape can be precisely formed on both sides of the arm in the vicinity of the journal.

  Further, by providing the second guide surface on either one or both of the upper surface 40b and the lower surface of the second tool 40, the second tool 40 can be used as the second jig 50 or the mold as in the first tool described above. Interference can be prevented and the movable range of the second tool can be sufficiently secured. Therefore, the forging material can be carried in and out smoothly.

  As in the case of the first jig, in order to prevent interference between the second jig 50 and the driving device (not shown) and to unify the direction in which the second jig 50 is moved, the eccentric direction of the pin portion It is preferable to further include a second jig 50 that is movable along the hatched arrows in FIGS. 7C and 7D. In this case, as with the first jig shown in FIGS. 6A to 6D, the second jig 50 has a second swing direction (broken line in FIGS. 7C and 7D) having an angle with the second guide direction by the second guide surface. The second tool 40 is held in a swingable manner (see the arrow).

  The second swinging direction can be appropriately set according to the second guiding direction, and can be, for example, a direction along the portion of the arm portion on which the second tool is pressed.

  The two second tools 40 may be pressed against the pin side surfaces of the two arm parts connected to the same journal part J and connected to the pin parts in the same phase. In this case, as shown in FIGS. 7A to 7D, the two second tools are preferably held swingably by a single second jig, respectively. Also by this, the configuration of the manufacturing apparatus can be simplified, and the movable range of the second tool can be secured more sufficiently.

  Further, the second tool may be pressed against the journal side surface of the first to third and sixth to eighth arm portions, for example, in the crankshaft of the four-cylinder to eight-piece counterweight shown in FIG. 1F. Good. In this case, it is possible to adopt a configuration in which one second tool is disposed between adjacent arm parts via the journal part and the second jig holds the one second tool.

3. Next, a method for using the forged crankshaft manufacturing apparatus of the present embodiment described above, that is, a forged crankshaft manufacturing method using the forged crankshaft manufacturing apparatus of the present embodiment described above will be described. Do.

  A manufacturing process can be made into the same structure as the former, for example, can be comprised in each process of preforming, die forging, deburring, and shaping. In this case, in order to obtain the forged material without burrs as shown in FIGS. 4A to 4C, in the die forging step, the forged material with burrs having the first surplus portion is formed in the arm portion with weight. The first surplus portion is provided on the outer periphery of each side portion near the journal portion, and protrudes from the outer periphery of each side portion. Further, the above-mentioned second surplus portion may be formed in the burred forged material. The second excess thickness portion is provided on the outer periphery of each side portion in the vicinity of the pin portion of the arm portion, and protrudes from the outer periphery.

  As described above, the weighted arm portion before shaping does not have a reverse gradient in any of the portion corresponding to the dent on the surface of the pin portion P side and the portion corresponding to the first surplus portion (Aca, Ada). In addition, the arm portion before shaping does not have an inverse gradient in any of the portion corresponding to the depression on the surface on the side of the journal portion J and the portion corresponding to the second surplus portion (Aaa, Aba). For this reason, it is possible to perform die forging without any trouble and to obtain a forged material with a burr. Subsequently, if burrs are removed from the forged material with burrs in the deburring step, a forged material without burrs can be obtained.

  In the shaping step, a forged crankshaft manufacturing apparatus as shown in FIGS. 6A to 6D is used. First, the upper tool and the lower tool of the mold are separated, and the first tool is placed in the retracted position. Then, the burr-free forging material is carried in and placed between the upper and lower dies.

Subsequently, by moving the first tool to the pressing position, the first tool is pressed against the forged material, specifically, against the surface on the pin portion side of the arm portion. In this state, the upper mold and the lower mold are moved close to each other. More specifically, the upper mold is moved to the bottom dead center, and the forging material is slightly pressed and pressed by the mold. Thereby, the forging material is subjected to shaping processing and corrected to the dimensional shape of the final product. At this time, the thickness of both side portions in the vicinity of the journal portion of the arm portion is increased by deforming the first surplus portion.

  After the shaping process and the processing to the first surplus portion are completed, the upper mold and the lower mold are separated from each other, and more specifically, the upper mold is moved to the top dead center. Then, after moving the first tool to the retracted position, the processed forging material is carried out. As a result, a crankshaft as shown in FIGS. 2A to 2D can be obtained, and weight reduction and securing of rigidity can be simultaneously achieved.

  When the burr-free forging material has the second excess thickness portion, the manufacturing device of the forged crankshaft may include a second tool that is pressed against the surface on the journal portion side of the arm portion. The second tool may be disposed at the pressing position or the retracted position following the first tool. As a result, a crankshaft as shown in FIGS. 3A to 3C can be obtained, and further weight reduction can be achieved while securing rigidity.

  The present invention can be effectively used for the manufacture of forged crankshafts mounted on reciprocating engines.

1: Forged crankshaft, J, J1 to J5: Journal section, P, P1 to P4: Pin section,
Fr: front part, Fl: flange part, A, A1 to A8: crank arm part,
W, W1-W8: counterweight part,
Aa, Ab: the side part near the pin part of the arm part,
Aaa, Aba: second surplus portion,
Ac, Ad: the side part of the arm part near the journal part,
Aca, Ada: first surplus portion,
As: Inner region of both side portions on the journal side surface of the arm portion,
At: Inner region of both sides on the pin side surface of the arm part,
11: Bottom side member constituting lower mold, 11a: mold engraving section,
11c: Opening part for jig, 11d: Recessed part,
12: Top side member constituting lower mold, 12a: mold engraving portion, 12b: tool opening,
12c: Opening part for jig, 12d: Recessed part,
20: first tool, 20a: tip surface (type engraving portion), 20b: top surface,
20c: lower surface, 20d: convex portion, 20e: side surface of convex portion (first guide surface)
30: 1st jig | tool, 30a: Convex part, 40: 2nd tool,
40a: tip surface (type engraving portion) 40b: upper surface 40d: convex portion
40e: side surface of the convex portion (second guiding surface), 50: second jig, 50a: convex portion,
91: Forgings without burrs

Claims (6)

The shape of the forged crankshaft in the manufacturing process of the forged crankshaft having a journal portion serving as a rotation center, a pin portion eccentric to the journal portion, and a crank arm portion connecting the journal portion and the pin portion. An apparatus for manufacturing a forged crankshaft that is shaped to correct the shape of a forged material without burrs,
The crank arm portion of the forged crankshaft is a weighted arm portion in which all or a part integrally has a counterweight portion,
The forging material has, in the arm portion with a weight, a first surplus portion projecting from the outer periphery on the outer periphery of each side portion in the vicinity of the journal portion,
The forged crankshaft manufacturing apparatus comprises:
Along with the shaping process, in the weighted arm part, a pair of upper and lower dies for performing a process of deforming the first surplus part and increasing the thickness of the both side parts near the journal part,
A first tool housed in the opening of the mold and pressed against at least the surface of the arm portion with weight on the side of the pin portion excluding at least the regions on both sides near the journal portion; ,
The mold and the first tool each have a first guiding surface for guiding the first tool from the retracted position to the pressing position,
An apparatus for manufacturing a forged crankshaft, wherein the first guide surface is provided on one or both of the upper surface and the lower surface of the first tool. The forged crankshaft manufacturing apparatus according to claim 1,
The apparatus for manufacturing a forged crankshaft further includes a first jig movable along an eccentric direction of the pin portion,
The first jig holds the first tool swingably in a first swing direction having an angle with a first guide direction by the first guide surface,
The manufacturing apparatus of a forged crankshaft, wherein the first tool moves along the first guiding direction in accordance with the movement of the first jig. The forged crankshaft manufacturing apparatus according to claim 2,
The first jig holds the two first tools so as to be able to swing in the first swing direction, respectively.
Manufacturing of a forged crankshaft in which the two first tools are pressed against the surface on the pin part side against the two arm parts with weights connected to the same pin part among the crank arm parts. apparatus. An apparatus for manufacturing a forged crankshaft according to any one of claims 1 to 3, wherein
The forging material further includes a second excess thickness portion that protrudes from the outer periphery on the outer periphery of each side portion in the vicinity of the pin portion of the crank arm portion,
The mold is further processed to deform the second excess thickness portion and to increase the thickness on both sides of the crank arm portion in the vicinity of the pin portion,
The forged crankshaft manufacturing apparatus is accommodated in an open portion of the mold, and is pressed against a surface of the crank arm portion on the journal portion side excluding at least the regions on both sides near the pin portion. Further comprising a second tool to be
The mold and the second tool each have a second guiding surface for guiding the second tool from the retracted position to the pressing position,
An apparatus for manufacturing a forged crankshaft, wherein the second guide surface is provided on one or both of the upper surface and the lower surface of the second tool. The forged crankshaft manufacturing apparatus according to claim 4,
The apparatus for manufacturing a crankshaft further includes a second jig movable along an eccentric direction of the pin portion,
The second jig holds the second tool swingably in a second swing direction having an angle with a second guide direction by the second guide surface,
The apparatus for manufacturing a forged crankshaft, wherein the second tool moves along the second guiding direction along with the movement of the second jig. The forged crankshaft manufacturing apparatus according to claim 5,
The second jig holds the two second tools so as to be able to swing in the second swing direction, respectively.
The two second tools are pressed against the surface of the journal portion side with respect to the two crank arm portions connected to the same journal portion of the crank arm portions and to the pin portion having the same phase. Forging crankshaft manufacturing equipment applied.