JP2008100270A - Manufacturing method of connecting rod - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a manufacturing cost by simplifying piercing work of a large end portion and a small end portion for an intermediate shape of a connecting rod integrally molded from the large end portion to the small end portion. <P>SOLUTION: A manufacturing method of a connecting rod includes the steps of: placing a workpiece W made of a third intermediate shape 18 on a recess 52 of a lower die 54 for piercing; inserting a guide rod 56 fixed to the upper die 62 for piercing through a guide hole 58 formed in the lower die 54 for piercing; and simultaneously piercing a large end hole 64a and a small end hole 64b on the large end portion 20a and the small end portion 20b of the workpiece W, by a first punch 66a and a small punch 66b fixed to the upper die 62 for piercing, in a state that the upper die 62 for piercing and the lower die 54 for piercing are positioned. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method of manufacturing a connecting rod constituting, for example, an engine component for a vehicle. More specifically, the present invention relates to a method of manufacturing a connecting rod having a large end and a small end, and then caps the large end. The present invention relates to a method for manufacturing a connecting rod that is divided into a rod part and a rod part.

  2. Description of the Related Art Conventionally, connecting rods (hereinafter also abbreviated as connecting rods) that connect a piston and a crankshaft of an internal combustion engine are known.

  In this type of connecting rod, the rod portion (main body portion) and the cap portion of the connecting rod are individually manufactured, and then the rod portion and the cap portion are integrally connected and assembled using a pair of bolts. An assembly type connecting rod is used (see Patent Documents 1 and 2).

  This assembly type connecting rod has a large end portion provided at one end portion and a small end portion provided at the other end portion, and the rod portion and the cap portion of the large end portion are separately manufactured. , And are integrally assembled by a pair of bolts. The assembly type connecting rod is assembled in a state where the cap portion is positioned with respect to the rod portion by fitting positioning pins into the pin hole of the rod portion and the pin hole of the cap portion, respectively.

  However, in the assembly type connecting rod, after the rod portion and the cap portion are individually forged and formed, bolt holes are drilled in the two parts of the rod portion and the cap portion, respectively. Therefore, it is necessary to process the mating surfaces into flat surfaces, which increases the number of processing steps and hinders production efficiency.

  Therefore, in recent years, after integrally forming the connecting rod from the large end portion to the small end portion by, for example, forging, the large end portion is broken and divided into a cap portion and a rod portion.

  That is, after the molded body in which the rod portion and the cap portion constituting the large end portion are integrally provided as the same member is integrally formed by, for example, forging molding, it is formed on the inner wall of the hole portion of the large end portion. With the cracking groove as a broken line, the large end portion is broken and divided into a rod portion and a cap portion, and the rod portion and the cap portion are integrally connected (coupled) via a pair of bolts. Manufactured by.

  The large end that is one end of the fracture split type connecting rod is provided with a large end hole composed of a large-diameter through hole, and the small end that is the other end on the opposite side along the axial direction. A small end hole made of a through hole having a smaller diameter than the large end hole is provided.

  The large end of the connecting rod is broken in a direction substantially perpendicular to the axial direction of the connecting rod near the center of the large end hole, with the cracking groove as the breaking line, thereby dividing the connecting rod into a rod portion and a cap portion. Is done. In this case, the fracture surface on the rod part side and the fracture surface on the cap part side are uneven and uneven, respectively, so that when the pair of bolts are attached, the uneven fracture surface on the rod part side and the unevenness on the cap part side The fracture surfaces are in close contact with each other, and both are assembled with high accuracy.

JP 63-57125 A JP 2004-144174 A

  By the way, when integrally forming the connecting rod from the large end portion to the small end portion by forging, for example, a large end hole penetrating the large end portion is formed by post-processing on the forged molded product, and the small It is necessary to form a small end hole penetrating the end. In this case, there is a desire to simplify post-processing after forging and reduce manufacturing costs.

  In the assembly type connecting rod, since the large end hole and the small end hole are formed in advance, it is not necessary to drill the large end hole and the small end hole by post-processing.

  An object of the present invention is to provide a manufacturing method of a connecting rod capable of simplifying post-processing after forging by subjecting a large end and a small end of a forged molded body to piercing at substantially the same time. There is to do.

  In order to achieve the above object, in the present invention, first, an intermediate formed body of a connecting rod integrally having a large end and a small end is used as a work, and the work is placed in a recess of a lower die. . Subsequently, the upper die and the lower die are positioned by lowering the upper die and inserting a guide rod fixed to the upper die into a guide hole formed in the lower die. The piercing process in which the upper die is further lowered and the large end hole and the small end hole are simultaneously drilled into the large end portion and the small end portion of the workpiece by the first punch and the second punch fixed to the upper die. Applied.

  When the piercing process is performed, the large end hole and the small end hole are formed in a state where the first punch and the second punch fixed to the upper die are positioned at predetermined positions with respect to the workpiece placed on the lower die. Drilled at the same time.

  In addition, after the upper die and the lower die are positioned, the workpiece is pressed toward the lower die side by a pressing plate provided on the upper die, and the workpiece is between the pressing plate and the lower die. It is good to perforate in the state pinched.

  According to the present invention, when the large end hole and the small end hole are simultaneously drilled into the large end portion and the small end portion of the workpiece by the first punch and the second punch fixed to the upper die, A guide rod fixed to the upper die is engaged with the guide hole to exert a guide function, so that the first punch and the second punch are positioned at predetermined positions with respect to the large end portion and the small end portion of the workpiece. It is drilled in the state that was done. As a result, the large end hole and the small end hole are formed with high accuracy with respect to predetermined positions of the large end portion and the small end portion of the workpiece.

  In the present invention, since the large end hole and the small end hole are simultaneously drilled with respect to the large end portion and the small end portion of the workpiece by the first punch and the second punch fixed to the upper die, post-processing after forging It is not necessary to perform piercing in the process, and post-processing can be simplified and manufacturing cost can be reduced.

  The method for manufacturing a connecting rod according to the present invention will be described in detail below with reference to the accompanying drawings by giving preferred embodiments in relation to a manufacturing apparatus for carrying out the method.

  In FIG. 1, reference numeral 10 indicates a forging apparatus that implements the method of manufacturing a connecting rod of the present invention. The forging apparatus 10 includes a plurality of first to fifth molds 12a to 12e in which the first to fifth steps are sequentially performed in succession (however, in FIG. 1, the first to fifth molds are used. The upper mold constituting 12a to 12e is omitted, and only the lower mold is shown).

  The outline of the forming process performed by the forging apparatus 10 is as follows. Forging material (not shown) heated to a predetermined temperature (for example, about 1250 degrees) is sequentially conveyed from a supply station (not shown) and supplied. The first intermediate forming body 14 (see FIG. 2A), which is approximately the shape of the molded product, is formed by applying a first roughing process by pressurizing the first intermediate forming body 14 and the first intermediate forming body 14. Further, by applying a second roughing process by pressurization, a second step in which a second intermediate molded body 16 (see FIG. 2B), which is a schematic shape of the molded product, is molded, and the second intermediate molded body 16 is further processed. A third process in which a third intermediate molded body 18 (see FIG. 2C) that approximates the shape of the second intermediate molded body 16 to a molded product is molded by pressurizing and finishing, and the third process. Forged 3rd inside A fourth step (FIG. 2D) in which piercing is performed to simultaneously pierce the piercing burrs 22a and 22b (see FIG. 2C) adhering to the large end 20a and the small end 20b of the molded body 18, and the outside of the third intermediate molded body 18 The fifth step (FIG. 2E) for trimming the outer burr 24 (see FIG. 2D) adhering to the edge side is continuously performed, whereby the connecting rod molded products 26a and 26b having a desired shape are obtained. can get.

  As shown in FIG. 2E, the molded products 26a and 26b are so-called two parallel arrangements in which a large end portion 20a and a small end portion 20b of a pair of connecting rods are arranged in parallel in opposite directions. Manufactured by molding.

  In this case, the forging apparatus 10 is a multi-step forging molding press capable of simultaneously performing multi-step stamping with a plurality of upper dies and lower dies composed of the first to fifth dies 12a to 12e. Therefore, the positioning accuracy of the upper and lower molds at the time of stamping is provided. The forging apparatus 10 includes a single upper mold (not shown) in which the first to fifth molds 12a to 12e are linearly arranged and a single lower mold 28.

  Further, on both sides of the first to fifth molds 12a to 12e in the arrangement direction, a pair of hollow and rail-like feed bars 30a and 30b are disposed to face each other in the horizontal direction with the lower mold 28 interposed therebetween. (See FIG. 1). The pair of feed bars 30a, 30b are spaced apart from the lower mold 28 by a predetermined distance and serve to automatically feed the formed body continuously to each forming step.

  The pair of feed bars 30a and 30b are arranged in a direction indicated by an arrow X along the arrangement direction of the first to fourth molds 12a to 12d and the first to fifth molds by a transfer mechanism (not shown) fixed to the apparatus body. Along the three axis directions consisting of the arrow Y direction approaching or separating toward the molds 12a to 12e and the arrow Z direction along the vertical direction (height direction) of the first to fifth molds 12a to 12d. Each is provided so as to be movable substantially simultaneously.

  A pair of clamp claws 32a and 32b for gripping the molded body in each step are disposed opposite to the pair of feed bars 30a and 30b, and the pair of clamp claws 32a and 32b are first to fourth gold. A plurality of the molds 12a to 12d are provided apart from each other at positions corresponding to the molds 12a to 12d. One clamp claw 32a (32b) detects the clamp state of the molded body by gripping the molded body and pressing a chuck portion (not shown) of the clamp claw 32a (32b) by the molded body. Each detection sensor is attached.

  Next, the fourth mold 12d used in the fourth step of simultaneously punching the pierce burrs 22a and 22b adhering to the large end portion 20a and the small end portion 20b of the third intermediate formed body 18 formed by forging in the third step. A schematic configuration is shown in FIGS.

  The fourth mold 12d includes a lower pierce die 42 fixed on the lower die cassette 40, and a pierce provided so as to approach or separate from the lower pierce die 42 under the action of a press ram (not shown). And an upper mold 44.

  The lower die 42 for piercing is not shown, a lower spacer 48 and a die plate 50 that are fixed in a state of being stacked on the lower die cassette 40 via a first fixing block 46a and a second fixing block 46b. A pierce lower die 54 fixed on the die plate 50 via a clamp mechanism and having a recess 52 on the upper surface on which the workpiece W (third intermediate molded body 18) is placed. The lower die 54 for piercing is supported in a floating manner by a floating mechanism (not shown) (for example, spring force of a spring member). Note that a plurality of guide holes 58 through which a plurality of guide rods 56 to be described later are inserted are formed at one end of the lower die 54 for piercing.

  The upper die 44 for piercing includes a press ram (not shown) that can be moved up and down via a lifting mechanism (not shown), an upper spacer 60 connected to the press ram, and the upper spacer 60 (not shown). An upper die 62 for piercing fixed to the upper die 62, and a first punch 66 a having a large diameter and fixed to the upper die 62 for piercing to pierce the large end portion 20 a of the workpiece W to form a large end hole 64 a and the workpiece W The small end portion 20b is drilled, and the small end hole 64b has a second punch 66b having a small diameter.

  Note that a total of two pairs of the first punch 66a and the second punch 66b are arranged corresponding to the parallel two-piece forming of the connecting rods, but for the sake of convenience, only the pair of the first punch 66a and the second punch 66b are illustrated. Illustration of the other pair of first punch 66a and second punch 66b is omitted.

  Further, the upper pierce die 44 is fixed to the upper pierce die 62 and is inserted into a guide hole 58 formed in the lower pierce die 54 to be mounted in the recess 52 of the lower pierce die 54. A plurality of guide rods 56 for positioning the first punch 66a and the second punch 66b with respect to the workpiece W placed thereon, and a floating mechanism supported by the upper die 62 for piercing via a support mechanism (not shown) A pressing plate 72 that presses the workpiece W toward the lower piercing die 54 side by the spring force of the load spring 70, and the pressing plate 72 interposed between the upper piercing die 62 and the pressing plate 72. Connected to a high-load spring 70 that urges the piercing lower die 54 in a pressing direction, and an actuator (not shown) such as a cylinder. It is and a knockout punch 74 for separating the first punch 66a and second punch 66b from the workpiece W by pressing against the upper surface on a piercing die 62 downward under the biasing action of the actuator.

  The forging apparatus 10 according to the embodiment of the present invention is basically configured as described above. Next, the operation and action of the fourth mold 12d along the flowchart shown in FIG. The effect will be described in detail below.

  First, as shown in FIG. 3, a state in which the upper pierce mold 44 is separated from the lower pierce mold 42 and waits at a predetermined upper position is set as an initial position.

  In such an initial position, the third intermediate molded body 18 (work W) including the outer burr 24 finished by the third mold 12c is a pair of clamp claws 32a and 32b of the pair of feed bars 30a and 30b. The workpiece W is conveyed to the lower piercing die 54 and placed in the recess 52 under the displacement action of the pair of feed bars 30a, 30b (step S1).

  Subsequently, the upper die for piercing 44 is integrally lowered under the driving action of a press ram (not shown) (step S2), and a plurality of guides fixed to the upper piercing die 62 before the pressing plate 72 contacts the workpiece W. By inserting the rod 56 into the guide hole 58 formed in the lower piercing die 54 (step S3), the upper piercing die 62 and the lower piercing die 54 are positioned, and the upper piercing die The first punch 66a and the second punch 66b fixed to 62 are positioned at predetermined positions with high accuracy with respect to the workpiece W (step S4).

  As the piercing upper die 44 continues further descending, the pressing plate 72 comes into contact with the upper surface of the workpiece W, and the workpiece W moves toward the piercing lower die 54 side by the spring force of the high load spring 70. Pressed (step S5). In other words, the workpiece W is held at a predetermined position while being pressed between the pressing plate 72 and the lower piercing die 54 under the action of the spring force of the high load spring 70.

  In this state where the workpiece W is positioned and held at a predetermined position, the upper piercing die 62 further moves down against the spring force of the high load spring 70, so that the piercing upper die 62 is integrated with the upper piercing die 62. Thus, the first punch 66a and the second punch 66b are lowered, and the large end hole 64a is punched into the large end portion 20a of the workpiece W by the first punch 66a, and at the same time, the workpiece is moved by the other second punch 66b. A small end hole 64b is formed in the small end portion 20b of W (step S6).

  That is, the piercing burr 22a attached to the large end portion 20a of the workpiece W is removed by the first punch 66a and the second punch 66b fixed to the upper pierce die 62, and at the same time, the small end portion 20b of the workpiece W is removed. The attached pierce burr 22b is removed, and piercing is performed to simultaneously drill the large end hole 64a and the small end hole 64b.

  In this case, since the first punch 66a and the second punch 66b are accurately positioned at predetermined positions with respect to the workpiece W under the guiding action by the guide hole 58 and the guide rod 56, the large end portion of the workpiece W is obtained. The large end hole 64a is drilled at a predetermined position where the large end hole 64a is positioned with respect to 20a, and at the same time, the small end hole 64b is punched at a predetermined position with respect to the small end portion 20b of the workpiece W.

  After the large end hole 64a and the small end hole 64b are formed with respect to the workpiece W under the punching action of the first punch 66a and the second punch 66b, the actuator (not shown) is energized to bring the knockout punch 74 downward. The pressure plate 72 is pressed downward by the knockout punch 74 by being displaced toward the bottom. Therefore, by the pressing action of the knockout punch 74, the first punch 66a and the second punch 66b are smoothly removed from the large end hole 64a and the small end hole 64b of the workpiece W, and the first punch 66a and the second punch 66b are removed. The workpiece W can be smoothly detached (step S7).

  In this case, the workpiece W contracts due to the temperature drop of the heated workpiece W, and after the large end hole 64a and the small end hole 64b are shot through, the meat of the workpiece W is formed on the outer peripheral surfaces of the first punch 66a and the second punch 66b. It is possible to prevent sticking.

  Finally, after the entire upper pierce mold 44 is separated from the lower pierce mold 42 and returned to the initial position (step S8), the large end hole 64a and the small end hole 64b are moved under the displacement action of the pair of feed bars 30a and 30b. The molded body that has been subjected to the piercing process is gripped by the clamp claws 32a and 32b of the feed bars 30a and 30b, conveyed to the fifth mold 12e, and the outer burr 24 attached to the outer edge of the fifth mold 12e. Is formed, a pair of connecting rod molded products 26a and 26b are obtained.

  In the present embodiment, the large end hole 64a and the small end portion 20b of the workpiece W are separated by the first punch 66a and the second punch 66b of the fourth mold 12d constituting the forging apparatus 10 with respect to the large end hole 64a and the small end portion 20b. Since the end holes 64b are drilled at the same time, it is not necessary to perform piercing in the post-processing step after forging and the post-processing can be simplified and the manufacturing cost can be reduced.

  In the present embodiment, when the large end hole 64a and the small end hole 64b are simultaneously drilled by the first punch 66a and the second punch 66b, the upper pierce die 62 for the piercing with respect to the guide hole 58 of the lower pierce die 54 is used. By engaging the guide rod 56 fixed to the center and exhibiting the guide function, the first punch 66a and the second punch 66b are positioned at predetermined positions with respect to the large end 20a and the small end 20b of the workpiece W. Perforated in the state of As a result, the large end hole 64a and the small end hole 64b are formed with high accuracy with respect to predetermined positions of the large end 20a and the small end 20b of the workpiece W.

  Further, in the present embodiment, the plurality of first to fifth molds 12a to 12e that sequentially perform from the first step for roughing the forging material to the fifth step for obtaining a molded product are linear. Production is performed by piercing forming the large end hole 64a and the small end hole 64b with the fourth die 12d disposed in the forging apparatus 10 using the forging apparatus 10 disposed in the vicinity of It becomes possible to mass-produce with improved efficiency.

  Furthermore, even when a pair of feed bars 30a and 30b that convey each intermediate formed body from the first step to the fifth step is used, the workpiece W is lowered for piercing by the pair of feed bars 30a and 30b. Piercing can be performed while the workpiece W is placed smoothly in the recess 52 of the die 54 and the workpiece W is positioned and held at a predetermined position.

It is a schematic structure perspective view of the forge forming apparatus which enforces the manufacturing method of the connecting rod of the present invention. It is process drawing which shows the shape of the intermediate molded object continuously shape | molded by the forge forming apparatus shown in FIG. It is a longitudinal cross-section schematic block diagram of the initial position where the upper mold | die for piercing and the lower mold | type for piercing of the 4th metal mold | die which comprise the forge forming apparatus shown in FIG. 1 were separated. FIG. 4 is a schematic longitudinal sectional view showing a state in which the upper pierce die is lowered from the state shown in FIG. 3 and a guide rod fixed to the upper pierce die is engaged with a guide hole formed in the lower pierce die. In the state where the upper die for piercing is further lowered from the state shown in FIG. 4 and the workpiece is clamped by the pressing plate and the lower die for piercing, the large end hole and the small end hole are simultaneously formed by the first punch and the second punch. It is a longitudinal cross-sectional schematic block diagram which shows the state pierced. FIG. 4 is a schematic longitudinal sectional view showing a state in which the upper die for piercing is raised and the first punch and the second punch are separated from the workpiece W. It is a flowchart which shows the process in which a large end hole and a small end hole are simultaneously drilled by the 1st punch and the 2nd punch with respect to the large end part and small end part of a workpiece | work by a 4th metal mold | die.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Forging apparatus 12a-12e ... Die 14, 16, 18 ... Intermediate molded object 20a ... Large end part 20b ... Small end part 22a, 22b ... Pierce burr 24 ... Outer burr 26a, 26b ... Molded product 30a, 30b ... Feed Bar 40 ... Lower die cassette 42 ... Lower die for piercing 44 ... Upper die 46a, 46b for piercing ... Fixing block 48 ... Lower spacer 50 ... Die plate 52 ... Recess 54 ... Lower die for piercing 56 ... Guide rod 58 ... Guide Hole 60 ... Upper spacer 62 ... Upper die for piercing 64a ... Large end hole 64b ... Small end hole 66a, 66b ... Punch 70 ... High load spring 72 ... Press plate 74 ... Knockout punch

Claims (2)

Placing a workpiece made of an intermediate molded body of connecting rods integrally having a large end and a small end in the recess of the lower die;
Lowering the upper die and inserting the guide rod fixed to the upper die into the guide hole formed in the lower die, thereby positioning the upper die and the lower die;
Further lowering the upper die and simultaneously drilling a large end hole and a small end hole with respect to the large end portion and the small end portion of the workpiece by a first punch and a second punch fixed to the upper die;
The manufacturing method of the connecting rod characterized by having. The method of claim 1, wherein
After the upper die and the lower die are positioned, the workpiece is pressed toward the lower die by the pressing plate provided on the upper die, and the workpiece is pressed between the pressing plate and the lower die. A method for manufacturing a connecting rod, wherein the connecting rod is perforated in the formed state.

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