JP6068309B2 - Crankshaft manufacturing method and apparatus - Google Patents

Description

  The present invention relates to a method for manufacturing a crankshaft having a hollow portion for weight reduction and an apparatus therefor.

  In internal combustion engines (engines) such as automobiles, weight reduction of components such as crankshafts is promoted from the viewpoint of improving fuel efficiency.

  Generally, a crankshaft has a journal shaft that is an output shaft of an engine, a crankpin that is pivotally supported by a connecting rod for transmitting motion of a piston, and a web (arm portion) that connects the journal shaft and the crankpin. . For example, weight reduction of the crankshaft is achieved by narrowing the solid forging material by improving the strength of material properties, hardening treatment, etc., but it is also effective to form a hollow part on the crankpin of the crankshaft etc. .

  By the way, the crankshaft differs in the number of crankpins formed and the phase (projection position in the circumferential direction around the journal axis) depending on the form of the engine (cylinder). For example, in a crankshaft of a V-type engine, the phases of adjacent crankpins are shifted such as 120 ° or 90 °. Therefore, in the manufacture of the crankshaft, a twisting process is often performed after the forging process to twist the crankshaft and change the phase of the crankpin. However, since there are problems such as an increase in manufacturing cost due to the implementation of the twisting process, a manufacturing method that omits the twisting process has been proposed as disclosed in, for example, Patent Document 1. That is, in the manufacturing method disclosed in Patent Document 1, the crankshaft is forged by a mold (molding die) so that the phases of the crankpins are different from each other in advance.

JP 2012-86265 A

  However, when the phase of the crankpin is changed in the forging process as disclosed in the above-mentioned Patent Document 1, there is another disadvantage that it is difficult to form the hollow portion in the crankpin. For example, in a crankshaft in which the phases of adjacent crankpins are shifted by 120 °, a structure in which a punch mechanism is installed around 120 ° in a mold of the crankshaft manufacturing apparatus is assumed. Therefore, the structure in the mold is complicated, and the manufacturing cost is expected to increase significantly. Furthermore, when a hollow part is formed in the web, the punch mechanism may interfere with a weight part provided on the opposite side of the crank pin across the journal shaft.

The present invention was made in connection with the manufacture of crankshafts, by appropriately installing the punch mechanism into a mold of the crank shaft, the manufacturing method of the crank shaft can favorably form a hollow portion and An object is to provide such a device.

To achieve the above object, the present invention includes a journal shaft, the phase of the crank pin each other in the axial center position displaced adjacent possess an axis parallel to the axis of the journal axis of the journal shaft a plurality of crank pins that are shifted 120 ° or 90 °, in the manufacturing method of the crank shaft having a pair of webs respectively supporting the crank pin projecting radially outwardly from said journal shaft, a first mold and the second mold A shaft forming step for forming the crankshaft by pressing a die, and a direction parallel to or perpendicular to the pressing direction of the first and second forming dies and perpendicular to the axis of the crankpin space forming the crankpin. The plurality of the clans are provided by a plurality of punch mechanisms including a movable part that is arranged so as to be able to advance and retreat, and a protruding part that is pushed out by advancement of the movable part. Kupyn and caused to enter the protrusion into the web have a hollow portion forming step of forming a hollow portion, respectively, the movable portion of the punch mechanism, the target web to directly form the hollow portion of the plurality of the web And the adjoining web adjacent to the target web .

Further, the present invention includes a journal shaft, the phase of the crank pin each other in the axial center position displaced adjacent possess an axis parallel to the axis of the journal axis of the journal axis deviated 120 ° or 90 ° In a crankshaft manufacturing apparatus that manufactures a crankshaft having a plurality of crankpins and a pair of webs that project radially outward from the journal shaft and support the crankpins, a first molding for molding the crankshaft by pressing -type and a second mold, disposed in said first and second molds, and a plurality of punches mechanisms respectively forming a hollow portion in a plurality of the crank pin and the web of the crankshaft to be molded The punch mechanism forms the crank pin parallel to or perpendicular to the pressing direction of the first and second molds. A movable portion arranged to be movable back and forth in a direction perpendicular to the axis of the crankpin space, and a protrusion that is pushed out by the advancement of the movable portion and enters the crankpin and the web. The movable portion is arranged to advance toward the crankpin between a target web that directly forms the hollow portion among the plurality of webs and an adjacent web adjacent to the target web. To do.

According to the above, in the manufacture of crankshafts, the pin portion constituted by the crank pin or web, it is possible to satisfactorily form a hollow portion for weight reduction. That is, since the punch mechanism is arranged in parallel or perpendicular to the pressing direction of the first and second molding dies, it can be easily provided for the first and second molding dies, and the first and second molding dies. The operating force at the time of pressing the mold can be used effectively. Furthermore, since the punch mechanism is disposed in a direction perpendicular to the axial center of the crank pin space, the pin portion can be formed with a hollow portion by moving forward and backward without interfering with the crankshaft web or the like. Accordingly, it is possible to easily form the hollow portion by the punch mechanism while forging the crankshaft in which the phases of the plurality of crankpins are shifted around the axis of the journal shaft by the forming die. As a result, production efficiency and production cost can be reduced.

  In this case, in the shaft forming step, pressing is performed by the first and second forming dies set so that the surface direction of the parting surface around the crankpin space passes through the axis of the crankpin space. Preferably it is done.

  The first and second molds of the crankshaft manufacturing apparatus are preferably set so that the surface direction of the parting surface around the crankpin space passes through the axis of the crankpin space. .

  Since the first and second molding dies are separated by a parting surface passing through the axis of the crankpin space, the crankshaft in which the phases of the plurality of crankpins are shifted around the axis of the journal shaft can be easily forged. Can do. Moreover, if the punch mechanism is arranged in the vicinity of the parting surface and along the surface direction of the parting surface, the punch mechanism can be installed more easily, and the shape of the hollow portion can be freely changed in design. It becomes possible.

Furthermore, the crank shaft, pre SL includes a shoulder portion inclined by a predetermined angle with respect to the projecting direction of the web at the surface of the web, in the hollow portion forming step, the punch mechanism, for shoulder forming said shoulder portion The projecting portion may be projected in a direction orthogonal to the space.

Furthermore, the crank shaft, pre SL includes a shoulder portion inclined by a predetermined angle with respect to the projecting direction of the web at the surface of the web, the punch mechanism, in a direction orthogonal to the space for the shoulder portions for forming a front Symbol shoulder the protrusions may Ru is protruded.

  Thus, a hollow part can be favorably formed with respect to the shoulder part of a crankshaft because a punch mechanism has a movable part and a protrusion part. Further, since the protruding portion advances and retreats in the orthogonal direction with respect to the shoulder portion, the bending of the protruding portion can be prevented and the durability of the manufacturing apparatus can be improved.

  According to the method and apparatus for manufacturing a crankshaft according to the present invention, the hollow portion can be satisfactorily formed by appropriately installing the punch mechanism in the crankshaft mold.

It is a perspective view which shows the shaping | molding die of the crankshaft manufacturing apparatus which concerns on one Embodiment of this invention. 2A is a plan view of the crankshaft of FIG. 1, FIG. 2B is a cross-sectional view taken along line IIB-IIB in FIG. 2A, and FIG. 2C is a cross-sectional view taken along line IIC-IIC in FIG. 2D is a cross-sectional view taken along line IID-IID in FIG. 2A. It is a perspective view which shows the fixed mold | type of FIG. It is a fragmentary sectional view which shows the punch mechanism of FIG. 1 schematically. It is a fragmentary sectional view showing roughly the punch mechanism concerning other composition examples. It is explanatory drawing which shows the manufacturing apparatus of FIG. 1 schematically. It is a perspective view which shows the shaping | molding die concerning a modification.

  Hereinafter, a crankshaft manufacturing method according to the present invention will be described in detail with reference to the accompanying drawings, taking a preferred embodiment in relation to a crankshaft manufacturing apparatus.

A crankshaft manufacturing apparatus 10 according to the present embodiment is an apparatus for manufacturing a crankshaft CS that is connected to a connecting rod and converts a reciprocating motion of a piston into a rotational motion in an engine such as an automobile (hereinafter also simply referred to as a manufacturing device 10). ). As shown in FIG. 1, the manufacturing apparatus 10 has a fixed mold 14 (first mold) and a movable mold 16 (second mold) as the mold 12, and presses the movable mold 16 against the fixed mold 14. Thus, the crankshaft CS is manufactured. In particular, the manufacturing apparatus 10 is configured to mold a crankshaft CS used for a three- cylinder engine.

Therefore, first , the configuration of the crankshaft CS of the three- cylinder engine will be described with reference to FIGS. 1 and 2A to 2D. The crankshaft CS includes four journal axes J (first to fourth journal axes J1 to J4), six webs W (first to sixth webs W1 to W6), and three crank pins P (first To third crank pins P1 to P3).

  The first to fourth journal shafts J1 to J4 are rotatably supported by a cylinder block of the engine and constitute a rotation shaft O of the crankshaft CS. Each of the journal shafts J1 to J4 has a column-shaped shaft-supported portion formed to have the same outer diameter, and the shaft-supported portions are separated from each other by a predetermined distance and arranged on the same axis (rotation axis O of the crankshaft CS). Is done. The first journal shaft J1 has a pivoted support portion in the vicinity of the connection portion with the first web W1, and protrudes from this portion so as to have a small diameter step by step. On the other hand, a disc-shaped attachment portion J41 for attaching a flywheel (not shown) is integrally formed on the protruding end portion of the fourth journal shaft J4.

  The first to sixth webs W1 to W6 are spaced apart from each other by sandwiching the first to fourth journal shafts J1 to J4 and the first to third crank pins P1 to P3 along the axial direction of the crankshaft CS. Placed. Specifically, the first web W1 is disposed between the first journal shaft J1 and the first crankpin P1, and connects the two. Similarly, the second web W2 connects the first crank pin P1 and the second journal shaft J2. The third web W3 connects the second journal shaft J2 and the second crankpin P2. The fourth web W4 connects the second crankpin P2 and the third journal shaft J3. The fifth web W5 connects the third journal shaft J3 and the third crank pin P3. The sixth web W6 connects the third crankpin P3 and the fourth journal shaft J4.

  Each of the webs W1 to W6 is formed in a flat plate shape that protrudes in a direction orthogonal to the rotation axis O of the crankshaft CS, and includes an arm portion Am that protrudes in opposite directions with respect to the rotation axis O, and a weight portion Wt. . Moreover, the planar shape of each web W1-W6 is designed in the shape which can be easily released from the shaping | molding die 12 (refer FIG. 2B-FIG. 2D).

  The arm portion Am is a portion that connects the journal shaft J and the crank pin P, the joint portion with the journal shaft J is wide, narrow along the protruding direction (direction toward the crank pin P), and the tip portion is It is formed in an arc shape. A shoulder portion Sr that is inclined with respect to the protruding direction of the arm portion Am is formed on the opposite surface of the portion of the arm portion Am that is connected to the crankpin P. That is, the thickness (dimension in the direction along the rotation axis O) of the arm portion Am of the portion where the shoulder portion Sr is formed is thin along the protruding direction.

  The weight part Wt has a larger area and weight than the arm part Am formed on the same web W. By providing this weight portion Wt, the center of gravity of each of the webs W1 to W6 is eccentric to the opposite side of the center of gravity of each of the pins P1 to P3 with respect to the rotation axis O of the crankshaft CS. Thereby, the balance between the center of gravity of each of the webs W1 to W6 and the center of gravity of each of the pins P1 to P3 is achieved.

  In addition, the first web W1 and the second web W2, the third web W3 and the fourth web W4, the fifth web W5 and the sixth web W6 are such that their planar shapes (arm portion Am, weight portion Wt) face each other. Is arranged. That is, the first web W1 and the second web W2 form a pair that supports the first crank pin P1 (hereinafter, the arm portion Am of the first web W1, the first crank pin P1, and the arm of the second web W2). A portion constituted by the portion Am is referred to as a first pin portion Pm1). Similarly, the third web W3 and the fourth web W4 form a pair that supports the second crankpin P2 (hereinafter, the arm portion Am of the third web W3, the second crankpin P2, and the fourth web W4). A portion constituted by the arm portion Am is referred to as a second pin portion Pm2.) Further, the fifth web W5 and the sixth web W6 form a pair that supports the third crankpin P3 (hereinafter, the arm portion Am of the fifth web W5, the third crankpin P3, and the arm of the sixth web W6). A portion constituted by the portion Am is referred to as a third pin portion Pm3).

  The first to third crank pins P1 to P3 are respectively supported by the webs W1 to W6, so that they are displaced radially outward from the axis (rotary axis O) of the journal axis J and parallel to the rotary axis O. Shaft axis OP (first to third axis centers OP1 to OP3). Each crankpin P1-P3 is formed in the column shape which has the axial direction length corresponding to a connecting rod, and the same outer diameter.

In the three- cylinder crankshaft CS, the phases of the mutual axial centers OP1 to OP3 of the first to third crankpins P1 to P3 (the protruding direction of the first to third pin portions Pm1 to Pm3) are There is a 120 ° deviation around the CS axis (rotation axis O). That is, the crankshaft CS is transmitted so that the reciprocating force of the connecting rods of the three cylinders is shifted every 120 ° rotation angle. As a result, a smooth torque can be output as the output shaft of the engine.

  The crankshaft CS has a hollow portion HW (first to sixth hollow portions HW1 to HW6) with respect to the first to third pin portions Pm1 to Pm3 (first to sixth webs W1 to W6) for weight reduction. Is formed. The first and second hollow portions HW1 and HW2 are formed obliquely from the outside to the inside of the first pin portion Pm1 so that the front end portions in the drilling direction are close to each other. Similarly, the third and fourth hollow portions HW3 and HW4 are formed obliquely from the outside to the inside of the second pin portion Pm2, and the fifth and sixth hollow portions HW5 and HW6 are formed of the third pin portion Pm3. It is formed obliquely from the outside to the inside.

  More specifically, each of the hollow portions HW1 to HW6 is formed to be orthogonal to the inclination of the shoulder portion Sr by a punch mechanism 70 described later. That is, the shoulder portion Sr is a portion set so that the punch mechanism 70 can easily form the hollow portion HW as the crankshaft CS itself becomes lighter. The hollow portion HW is satisfactorily provided by the punch mechanism 70 that faces the shoulder portion Sr (advances and retracts in the orthogonal direction). The crankshaft CS does not have the shoulder portion Sr on the sixth web W6, but the sixth hollow portion HW6 is formed obliquely with respect to the web W in the same manner as the other hollow portions HW1 to WH5.

  The form (shape, area, and depth of the holes) of each of the hollow portions HW1 to HW6 is desirably set as appropriate depending on the weight of the crankshaft CS, the shape of the web W, and the like. For example, the hollow portion HW may be formed to a depth reaching the crank pin P from the shoulder portion Sr through the web W. Furthermore, each hollow part HW1-HW6 is good to be formed in a mutually different shape in consideration of the vibration characteristic etc. of an engine.

  Next, the manufacturing apparatus 10 will be described. As shown in FIG. 1, the molding die 12 has a parting surface 18 on which the fixed die 14 and the movable die 16 are separated, and the parting surface 18 is an upper surface 14 a of the fixed die 14 (facing the first molding die side. Surface) and the lower surface 16a of the movable die 16 (second molding die side facing surface). A fixed mold side space 20 is formed on the upper surface 14a, and a movable mold side space 22 is formed on the lower surface 16a. The fixed mold side space 20 and the movable mold side space 22 form a crankshaft forming space 24 for forming the above-described crankshaft CS in a contact state between the fixed mold 14 and the movable mold 16.

  As shown in FIGS. 1 and 3, the crankshaft forming space 24 has a journal shaft space 30, a web space 40, and a crankpin space 50, and these spaces are connected to form one forming cavity. Configured as

  The journal shaft space 30 has first to fourth journal shaft spaces 31 to 34 for forming the first to fourth journal shafts J1 to J4. In this case, the parting surfaces 18 around the first to fourth journal shaft spaces 31 to 34 are planes having the same height, and the surface direction of each of the first to fourth journal shaft spaces 31 to 34 is the same. It is set to pass through the axis. That is, the first to fourth journal shaft spaces 31 to 34 are formed by being divided into the fixed mold side space 20 and the movable mold side space 22 in half.

  The crankpin space 50 has first to third crankpin spaces 51 to 53 for forming the first to third crankpins P1 to P3. Here, the phases of the first to third crank pins P1 to P3 are shifted from each other by 120 ° around the axis of the journal shaft J (rotation axis O) as described above. Thus, even if the phases of the first to third crank pins P1 to P3 are shifted, the surface direction of the parting surface 18 passes through the respective shaft centers 51a to 53a of the first to third crank pin spaces 51 to 53. Is set to

  Specifically, the parting surfaces 18 around the first to third crankpin spaces 51 to 53 are stepped with respect to the parting surfaces 18 around the first to fourth journal shaft spaces 31 to 34. It is formed. That is, the upper surface 14a of the fixed mold 14 is formed such that the periphery of the first and third crankpin spaces 51 and 53 is lower than the periphery of the first to fourth journal shaft spaces 31 to 34. Further, the periphery of the second crankpin space 52 is formed higher than the periphery of the first to fourth journal shaft spaces 31 to 34. Eventually, the first to third crankpin spaces 51 to 53 are also divided into a fixed mold side space 20 and a movable mold side space 22 and formed in half.

  On the other hand, the web space 40 includes first to sixth web spaces 41 to 46 for forming the first to sixth webs W1 to W6. In this case, the parting surfaces 18 around the first to sixth web spaces 41 to 46 can be separated from the mold 12 according to the shape and phase of the webs W1 to W6 to be molded. Is set as appropriate. In addition, the first to fifth web spaces 41 to 45 have shoulder portion spaces 60 for forming the shoulder portions Sr on the arm portions Am of the web W. The outer portion of the wall portion 60a constituting the shoulder portion space 60 is inclined at a predetermined angle with respect to the axial centers 51a to 53a of the first to third crankpin spaces 51 to 53, and forms a hollow portion HW. A communication hole 62 communicating with the mechanism 70 is provided.

  The punch mechanism 70 (first to sixth punch mechanisms 71 to 76) includes a punch portion 70a that forms a hollow portion HW in the crankshaft CS, and an arrangement portion 70b that is provided in the molding die 12 and that allows the punch portion 70a to be freely moved back and forth. Prepare. As shown in FIG.1 and FIG.4, the punch part 70a (1st-6th punch part 71a-76a) is an action part which forms the 1st-6th hollow part HW1-HW6 separately in crankshaft CS. . The arrangement portion 70b (first to sixth arrangement portions 71b to 76b) is a housing portion for the first to sixth punch portions 71a to 76a. The first, second, fifth, and sixth arrangement parts 71b, 72b, 75b, and 76b are provided on the fixed mold 14 side, and the third and fourth arrangement parts 73b and 74b are provided on the movable mold 16 side.

  Further, each of the placement portions 71b to 76b is formed in a substantially cylindrical shape in the molding die 12, and is parallel or perpendicular to the pressing direction X of the molding die 12, and the axis of the first to third crankpin spaces 51 to 53. It is set to be orthogonal to the cores 51a to 53a (see FIG. 3). Specifically, the first and second arrangement portions 71 b and 72 b are at a position slightly deeper than the upper surface 14 a around the first crankpin space 51 and perpendicular to the pressing direction X of the mold 12 and the first crankpin space. It is formed so as to be orthogonal to the shaft center 51a of 51. The third and fourth arrangement portions 73b and 74b are formed in the movable die 16 so as to be parallel to the pressing direction X (perpendicular to the lower surface 16a) and orthogonal to the axis 52a of the second crankpin space 52. . The fifth and sixth arrangement portions 75 b and 76 b are slightly deeper than the upper surface 14 a around the third crankpin space 53 and are perpendicular to the pressing direction X and orthogonal to the axial center 53 a of the third crankpin space 53. Formed as follows.

  The vicinity of the crankshaft forming space 24 of each of the placement portions 71b to 76b includes a bent space 77 that is bent with respect to the axial center of each placement portion 70b and that extends in a direction orthogonal to the wall portion 60a that constitutes the shoulder portion space 60. . An end portion of the bent space 77 communicates with the shoulder portion space 60 through the communication hole 62.

  And the 1st-6th punch part 71a-76a is arrange | positioned so that a movement in parallel or perpendicularly to the press direction X is possible along the 1st-6th arrangement | positioning parts 71b-76b formed as mentioned above. Each punch part 71a-76a is movable rod 78 (movable part) inserted in the orthogonal direction with respect to the side or upper surface of the mold 12 having a square shape, and is disposed at the tip of the movable bar 78 and can be pushed out by the movable bar 78. And a protruding body 79 (protruding portion).

  The movable rod 78 of the punch portion 70a has a base end portion protruding from the mold 12 fixed to first to sixth punch drive mechanisms 93 to 98 (see FIG. 6), which will be described later, and drives the punch drive mechanisms 93 to 98. The inside of the mold 12 can be advanced and retracted by receiving force. An extruding surface 78 a capable of extruding the protrusion 79 is formed at the tip of the movable rod 78. The extrusion surface 78a is inclined at a predetermined angle so as to be pushed out while being in contact with the base end surface 79a of the protrusion 79.

  The protrusion 79 is a member for forming a hollow portion that advances toward the first to third pin portions Pm1 to Pm3 formed in the crankshaft forming space 24 and is inserted into the hollow portion HW. . Most of the protruding body 79 is disposed in the bending space 77 and guided in the axial direction of the bending space 77. The projecting body 79 of each of the punch portions 71a to 76a has a cross-sectional shape corresponding to the shape of the hollow portion HW to be formed, and has a predetermined longitudinal length (can be advanced into the web space 40 and the crankpin space 50). Length). The base end surface 79 a of the projecting body 79 is inclined at a predetermined angle so as to face the extrusion surface 78 a of the movable rod 78.

  Further, a flange portion 80 in which one end of the spring 81 is disposed is formed at the base end portion of each protrusion 79. The other end of the spring 81 comes into contact with the seat 82 of the mold 12 formed near the wall 60 a of the shoulder space 60 and biases the projecting body 79 away from the seat 82. That is, the flange portion 80, the spring 81, and the seat 82 constitute a return mechanism 84 for returning the projecting body 79 pushed out by the movable rod 78. The configuration of the return mechanism 84 is not particularly limited. For example, a hook portion that is hooked on the protrusion 79 is provided in the movable rod 78, and a spring that pulls the protrusion 79 is provided in the movable rod 78. It can take a configuration.

  The configuration of the punch mechanism 70 is not limited to the configuration shown in FIG. For example, as in another configuration example shown in FIG. 5, the punch mechanism 70 </ b> A includes a punch portion 70 a configured by a cylinder 86 having a projecting body 85 (projection portion), and the cylinder 86 is disposed in the placement portion 70 b. It can be. The cylinder 86 includes, for example, a drive transmission portion 86 a that receives an operating force in the vertical direction of the movable mold 16 described later to advance and retract the protrusion 85. The protruding body 85 is accommodated in the cylinder 86 in a normal state, and advances into the shoulder space 60 under the action of the drive transmission portion 86a, thereby forming a hollow portion HW in the crankshaft CS.

  The manufacturing apparatus 10 applies stress (punch force) for forming the hollow portion HW to the punch mechanism 70 described above. At this time, the manufacturing apparatus 10 is configured to transmit a pressing force for pressing the movable die 16 to the fixed die 14 to the punch mechanism 70 to operate the punch mechanism 70. Hereinafter, a specific configuration will be described with reference to FIG.

  In the manufacturing apparatus 10, a lower plate 89 is provided on the bolster 88, and an upper plate 91 is provided on the lower surface of a press ram 90 that can move in the vertical direction with respect to the bolster 88. The fixed die 14 is attached on the lower plate 89, and the movable die 16 is attached to the upper plate 91 via a load adjusting means 92 (for example, a cylinder device or the like).

  The manufacturing apparatus 10 includes first to sixth punch drive mechanisms 93 to 98 that are connected to the movable rod 78 of the first to sixth punch portions 71a to 76a protruding from the side portion and the upper portion of the mold 12. The first, second, fifth and sixth punch drive mechanisms 93, 94, 97, 98 convert the moving force in the vertical direction (downward) of the press ram 90 into the horizontal direction (perpendicular to the pressing direction X). , To the first, second, fifth and sixth punch portions 71a, 72a, 75a, 76a.

  The first, second, fifth and sixth punch drive mechanisms 93, 94, 97, 98 take the form of cam mechanisms. That is, each punch drive mechanism 93, 94, 97, 98 is supported by the upper plate 91 and moves in the vertical direction together with the upper plate 91, and the cam block 100 is pushed toward the mold 12 by the cam driver 99. And have. The cam block 100 is provided with a spring 101 to which the movable rod 78 of the first, second, fifth and sixth punch portions 71a, 72a, 75a, 76a is fixed and pulls back the pushed cam block 100. The cam driver 99 is provided with an inclined portion 99a, and the cam block 100 is provided with an inclined portion 100a. When the press ram 90 is at the top dead center, the cam driver 99 is separated from the cam block 100, and the inclined portion 99a and the inclined portion 100a are not in contact with each other. As the press ram 90 is lowered, the inclined portion 99a and the inclined portion 100a come into contact with each other, and the cam block 100 moves toward the mold 12 as the inclined portions 99a and 100a slide.

  Thereby, the movable rod 78 of the first, second, fifth and sixth punch portions 71a, 72a, 75a, 76a advances toward the back side in the fixed die 14 (to the crankshaft forming space 24), The protrusion 79 is pushed out. The projecting body 79 advances in the bending space 77 and projects into the shoulder space 60 through the communication hole 62, and the first and second hollow portions HW1 and HW2 are provided in the first pin portion Pm1, and the third pin portion. The fifth and sixth hollow portions HW5 and HW6 are formed in Pm3, respectively.

  On the other hand, the third and fourth punch driving mechanisms 95 and 96 transmit the moving force in the vertical direction (downward) of the press ram 90 to the third and fourth punch portions 73a and 74a as they are. The third and fourth punch drive mechanisms 95, 96 are configured to receive the moving force of the press ram 90 separately from the movable die 16 in the load adjusting means 92. The punch portions 73a and 74a are operated independently. Accordingly, the movable rod 78 of the third and fourth punch portions 73a and 74a advances downward to push out the protrusion 79, and the protrusion 79 is connected to the second pin portion Pm2 by the third and fourth hollow portions HW3, HW4 is formed.

  The structure of the first to sixth punch drive mechanisms 93 to 98 is not particularly limited. For example, an actuator (cylinder device, linear motor, or the like) that can operate independently of the vertical movement of the press ram 90 is used. There may be.

  The manufacturing apparatus 10 according to the present embodiment is basically formed as described above, and a method for manufacturing the crankshaft CS will be specifically described below.

  First, as shown in FIG. 6, the preform A (the crankshaft CS before being forged) is placed in the fixed mold side space 20 of the fixed mold 14. The preform A can be manufactured by a conventionally known method such as hot forging or casting.

  After placement of the preform A, the manufacturing apparatus 10 presses the movable die 16 against the fixed die 14 to form the crankshaft CS (shaft forming step). The manufacturing apparatus 10 moves the press ram 90 downward from the top dead center (pressing direction X), presses the preform A with the fixed mold 14 and the movable mold 16, and moves the movable mold 16 on the upper surface 14 a of the fixed mold 14. The lower surface 16a is brought into contact. As a result, the crankshaft CS is forged by the constructed crankshaft forming space 24.

  The manufacturing apparatus 10 performs the hollow part formation process which shape | molds the 1st-6th hollow parts HW1-HW6 in the 1st-3rd pin parts Pm1-Pm3 of crankshaft CS simultaneously with this shaft formation process. At this time, the manufacturing apparatus 10 transmits the moving force in the pressing direction X of the press ram 90 to the first to sixth punch portions 71a to 76a by the first to sixth punch drive mechanisms 93 to 98. That is, the press ram 90 and the cam driver 99 are integrally moved downward to bring the inclined portion 99a into contact with the inclined portion 100a of the cam block 100. Then, as the cam driver 99 further moves downward, the cam block 100 is advanced toward the fixed mold 14. As a result, the movable rods 78 of the first, second, fifth and sixth punch portions 71 a, 72 a, 75 a and 76 a advance to the back side of the fixed mold 14. Simultaneously with the operation timing of the first, second, fifth and sixth punch portions 71a, 72a, 75a, 76a, the movable rod 78 of the third and fourth punch portions 73a, 74a also moves in the pressing direction X of the press ram 90. Under the moving force, it advances to the back side of the movable mold 16.

  As a result, the movable rods 78 of the first to sixth punch portions 71a to 76a advance and move substantially simultaneously, and simultaneously push the protrusions 79 shown in FIG. 4 into the shoulder portion space 60. The protrusion 79 is inserted into the preform A that is advanced toward the shoulder portion Sr of the preform A and forged. Thereby, the first to sixth hollow portions HW1 to HW6 are formed in the first to third pin portions Pm1 to Pm3 of the crankshaft CS. Since the protrusion 79 advances in the orthogonal direction with respect to the shoulder portion Sr, inconveniences such as deviation of the advancement direction are prevented, and the hollow portion HW can be easily formed.

  After forming the crankshaft CS having the hollow portion HW, the fixed die 14 and the movable die 16 are separated by moving the press ram 90 upward from the bottom dead center. In the first, second, fifth and sixth punch drive mechanisms 93, 94, 97 and 98, the cam block 100 is pulled back by the spring 101 when the press ram 90 moves. As a result, the movable rod 78 of the first, second, fifth and sixth punch portions 71a, 72a, 75a and 76a is retracted. The third and fourth punch drive mechanisms 95 and 96 move the movable rod 78 of the third and fourth punch portions 73a and 74a backward as the press ram 90 moves. Each protrusion 79 is returned from the crankshaft forming space 24 into the arrangement portion 70b by the return mechanism 84, and the forged crankshaft CS is left in the fixed die side space 20 of the fixed die 14.

As described above, according to the crankshaft CS manufacturing method and manufacturing apparatus 10 according to the present embodiment, the first to third pin portions Pm1 to Pm3 of the three- cylinder crankshaft CS can be reduced in weight. The hollow part HW can be formed satisfactorily. In particular, the manufacturing apparatus 10 is configured so that the parting surface 18 of the molding die 12 is separated by the journal shaft space 30 and the crankpin space 50 so that the crankshaft CS can be forged without the twisting process. Set to Even in the molding die 12 set in this way, the hollow portion HW can be accurately molded by appropriately arranging the punch mechanism 70.

Here, in the crankshaft CS of the three- cylinder engine, the phases of the three crankpins P are shifted by 120 ° around the journal shaft J. For this reason, in general, it can be assumed that the punch mechanism is installed obliquely in the mold according to the phase of the crankpin P, but the internal structure of the rectangular mold becomes complicated. In contrast, the punch mechanism 70 according to the present embodiment is parallel or orthogonal to the pressing direction X of the mold 12 and is orthogonal to the axial centers 51a to 53a of the first to third crankpin spaces 51 to 53. Therefore, the structure in the mold 12 is simplified. Further, the first, second, fifth and sixth punch mechanisms 71, 72, 75, 76 can be arranged in the vicinity of the parting surface 18 and along the surface direction of the parting surface 18, and each punch The mechanism 70 can be installed more easily. Furthermore, the punch mechanism 70 can be easily replaced, and the shape and the like of the hollow portion HW can be freely changed.

  In addition, the punch mechanism 70 arranged in parallel or perpendicular to the pressing direction X of the mold 12 can be operated based on the operating force easily transmitted when the mold 12 is pressed. That is, it is not necessary to prepare a separate drive source for operating the punch mechanism 70, and the apparatus can be further simplified.

  Furthermore, the punch mechanism 70 disposed in the direction orthogonal to the shaft centers 51a to 53a of the first to third crankpin spaces 51 to 53 performs an advance / retreat operation without interfering with the web W or the like of the crankshaft CS. Thereby, the hollow portion HW can be easily formed by the punch mechanism 70 while the crankshaft CS in which the phase of the crankpin P is shifted around the axis of the journal axis J is easily forged by the mold 12. Become.

  Furthermore, since the punch mechanism 70 includes the movable rod 78 and the projecting body 79, the advancing direction of the projecting body 79 can be easily changed with respect to the advancing direction of the movable rod 78. Therefore, the projecting body 79 can be moved back and forth in the orthogonal direction to the shoulder portion Sr inclined with respect to the axis OP of the crankpin P, and the hollow portion HW can be favorably formed. Further, since the protruding body 79 is prevented from bending during forward / backward movement, the manufacturing apparatus 10 can improve the durability of the entire apparatus.

  Therefore, according to the manufacturing method and manufacturing apparatus 10 of the crankshaft CS described above, it is possible to improve the efficiency at the time of manufacturing the crankshaft CS, reduce the manufacturing cost of the crankshaft CS, and the like.

  In addition, the manufacturing apparatus 10 can design freely about the structure of the shaping | molding die 12 which shape | molds the crankshaft CS, For example, you may employ | adopt the shaping | molding die 12A which concerns on the modification shown in FIG. . The molding die 12A has a crankshaft molding space 24A in which the second crankpin P2 faces the lateral direction of the molding die 12A. In this case, the parting surface 18A around the first crankpin space 51A that is 120 ° out of phase with the second crankpin space 52A is set higher than the parting surface 18A around the journal shaft space 30A. . Further, the parting surface 18A around the third crankpin space 53A is set lower than the parting surface 18 around the journal shaft space 30A. Accordingly, the surface direction of the parting surface 18A of the mold 12A is set so as to pass through the shaft centers of both the first to fourth journal shafts J1 to J4 and the first to third crank pins P1 to P3.

  The punch mechanism 70 is provided in the molding die 12A according to the shape of the crankshaft molding space 24A. For example, the first and second punch mechanisms 71 and 72 (not shown) are provided in the movable die 16A so as to be orthogonal or parallel to the pressing direction X and orthogonal to the axis of the first crankpin P1. . The third and fourth punch mechanisms 73 and 74 are provided between the fixed die 14A and the movable die 16A (parting surface 18A) so as to be orthogonal to the pressing direction X and the axis of the second crankpin P2. The fifth and sixth punch mechanisms 75 and 76 (not shown) are provided in the fixed die 14A so as to be orthogonal or parallel to the press direction X and orthogonal to the axis of the third crank pin P3.

As described above, even when the molding die 12A according to the modification is employed, the same effect as that of the molding die 12 shown in FIG. 1 can be obtained, and the hollow portion HW is excellent in the crankshaft CS for three cylinders. Can be formed.

In the above description, the present invention has been described with reference to preferred embodiments. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention. Yes. For example, the present invention is not limited to the crankshaft CS of a three- cylinder engine, but can be applied to a crankshaft CS of an engine configured for a V-type multicylinder. At this time, the phase around the axis of the journal shaft J of the crankpin P is appropriately changed (for example, 90 °) according to the number of cylinders. Even in this case, the punch mechanism 70 is provided in the mold 12 so as to be movable back and forth in a direction parallel or perpendicular to the press direction X and perpendicular to the axis of the crankpin space 50 forming the crankpin P. The hollow part HW can be formed satisfactorily.

10 ... Crankshaft manufacturing equipment (manufacturing equipment)
12, 12A ... Molding die 14, 14A ... Fixed die 14a ... Upper surface 16, 16A ... Movable die 16a ... Lower surface 18, 18A ... Parting surfaces 24, 24A ... Crankshaft molding space 30 ... Journal shaft space 40 ... Web space 50 ... Space for crank pin 60 ... Space for shoulder portion 70 ... Punch mechanism 78 ... Movable rod 79 ... Projection body Am ... Arm portion CS ... Crank shaft HW ... Hollow portion J ... Journal shaft P ... Crank pin Sr ... Shoulder portion W ... Web Wt ... Weight part X ... Press direction

Claims (6)

And journal axis, and a plurality of crankpins phase of the crank pin adjacent possess an axis parallel to the axis of the journal axes that are shifted 120 ° or 90 ° with the axial center offset position of the journal axis, In a method of manufacturing a crankshaft having a pair of webs that project radially outward from the journal shaft and respectively support the crankpin,
A shaft forming step of forming the crankshaft by pressing a first mold and a second mold;
A movable part arranged parallel to or perpendicular to the pressing direction of the first and second molding dies and movable in a direction perpendicular to the axis of the crankpin space forming the crankpin , and advancement of the movable part a plurality of punches mechanism including a projecting portion that is pushed out by the, have a hollow portion forming step in which a plurality of the crank pin and by entering the projecting portion to the web to form a hollow portion, respectively,
The movable part of the punch mechanism is arranged so as to advance toward the crank pin between a target web that directly forms the hollow part among the plurality of webs and an adjacent web adjacent to the target web. A manufacturing method of a crankshaft characterized by the above. In the manufacturing method of the crankshaft of Claim 1,
In the shaft forming step, pressing is performed by the first and second forming dies set so that the surface direction of the parting surface around the crankpin space passes through the axis of the crankpin space. A method for manufacturing a crankshaft. In the manufacturing method of the crankshaft of Claim 1 or 2,
The crank shaft, pre SL includes a shoulder portion inclined by a predetermined angle with respect to the projecting direction of the web at the surface of the web,
In the hollow portion forming step , the punch mechanism causes the protruding portion to protrude in a direction orthogonal to a shoulder portion space for forming the shoulder portion. And journal axis, and a plurality of crankpins phase of the crank pin adjacent possess an axis parallel to the axis of the journal axes that are shifted 120 ° or 90 ° with the axial center offset position of the journal axis, In a crankshaft manufacturing apparatus that manufactures a crankshaft having a pair of webs that project radially outward from the journal shaft and respectively support the crankpin,
A first mold and a second mold for molding the crankshaft by pressing;
Wherein provided in the first and second molds, and a plurality of punches mechanisms respectively forming a hollow portion in a plurality of the crank pin and the web of the crankshaft to be molded,
The punch mechanism is a movable part arranged so as to be movable back and forth in a direction parallel or perpendicular to the pressing direction of the first and second molding dies and perpendicular to the axis of the crankpin space forming the crankpin ; A projecting portion that is pushed out by advancement of the movable portion and enters the crankpin and the web,
The movable part of the punch mechanism is arranged so as to advance toward the crank pin between a target web that directly forms the hollow part among the plurality of webs and an adjacent web adjacent to the target web. The crankshaft manufacturing apparatus characterized by the above-mentioned. In the crankshaft manufacturing apparatus according to claim 4,
The crankshaft manufacturing apparatus, wherein the first and second molding dies are set so that a surface direction of a parting surface around the crankpin space passes through an axis of the crankpin space. In the crankshaft manufacturing apparatus according to claim 4 or 5,
The crank shaft, pre SL includes a shoulder portion inclined by a predetermined angle with respect to the projecting direction of the web at the surface of the web,
The punch mechanism, before Symbol crankshaft production apparatus, characterized in that the projecting portion in the orthogonal direction of the shoulder portion space for molding the shoulder portion Ru is protruded.

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