JP2012228707A - Forging method and system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a forging method that can carry out forging such as closed forging superior in productivity and stable in quality.SOLUTION: The forging method is characterized in that a die is replaceably set in a forging press machine to manufacture a connecting rod by closed forging, and the die is removed from the press machine each time after one forging molding process and replaced with another die. The die includes a pair of closed dies 12 horizontally movable close to and away from each other, and a die case 11 for housing the closed dies 12. The die case 11 is configured to drive the pair of closed dies 12 together in a mold clamping direction based on the roll-separating force of the forging press machine, and the closed dies 12 are removed from the forging press machine with a forged product each time after one forging molding process and replaced with another pair of closed dies 12.

Description

  The present invention relates to a forging method and a forging system for so-called die forging such as closed forging.

  As a closed forging method for a connecting rod of an internal combustion engine, a method described in Patent Document 1 has been proposed.

  In the closed forging method described in Patent Document 1, after adopting a lower die divided into four as a die, using a preform formed in advance with a volume distribution corresponding to each component of the connecting rod, A connecting rod is manufactured by a so-called single-cut method by closed forging in which the timing of pressing from three directions (front and rear, left and right and up and down) is changed.

JP-A-4-197546

  However, the closed forging method described in Patent Document 1 is not only a so-called single take (punching) closed forging method, but of course, cleaning for the purpose of removing scales or the like every molding cycle (or Cleaning) and a lubricant application work are essential, and the improvement in productivity is limited due to the long cycle time. In addition, when closed forging of products of other specifications, it is necessary to replace the entire mold, and it takes a long time to replace the mold, making it difficult to cope with so-called small-quantity production of other products.

  The present invention has been made by paying attention to such problems, and provides a forging method and a forging system that are particularly excellent in productivity and capable of performing closed forging with stable quality.

  In the forging method according to the present invention, a die is set in a forging press machine so as to be detachable and die forging is performed, and the die is taken out from the forging press machine each time forging is performed, and another die is formed. It is based on the exchange.

  In this case, it is desirable to wait for the next mold to be put into a standby area adjacent to the forging press. Further, as the mold, for example, it has a pair of inner molds that can approach and separate in the horizontal direction and an outer mold that accommodates the inner mold, and the outer mold is based on the rolling force of the forging press machine. A pair of inner dies are driven in the clamping direction, and the inner die is taken out of the forging press with the work after forging and replaced with another inner die for each forging process. To do.

  According to the present invention, since the mold can be changed for each forging process, it is possible to immediately shift to the next forging molding cycle, so that the cycle time is short and the productivity is high. Can respond flexibly. In addition, since forging is performed with a new die each time, the quality and stability of the forged molded product can be improved.

  In addition, cleaning (or washing) for removing scales and applying lubricants can be performed outside the forging press, so these incidental operations do not affect the cycle time and are much more productive. It becomes.

The schematic perspective view which shows the shape after the forge of the connecting rod used as the manufacture object of this invention. The expanded sectional view which follows the AA line of FIG. It is a figure which shows embodiment of this invention, and is schematic explanatory drawing of the metal mold | die for closure forging used for the forging of the connecting rod shown in FIG. Explanatory drawing which shows the state which the closure die of the metal mold | die for closure forging shown in FIG. 3 reached the bottom dead center. Explanatory drawing which shows the state which the punch for large ends of the metal mold | die for closed forging shown in FIG.3, 4 reached the bottom dead center. Cross-sectional explanatory drawing which follows the BB line of FIG. It is an enlarged view of FIG. 6, Comprising: Explanatory drawing when the shaping | molding surface of the punch for large ends is a flat surface. The principal part enlarged view of FIG. Explanatory drawing of the raw material meat flow direction in FIG. 6 is a schematic plan view of a forging system for the purpose of adopting and replacing the closed forging die shown in FIGS. Front explanatory drawing of FIG.

  FIGS. 1-6 has shown an example of the closing forging method of a connecting rod as a more concrete form for implementing this invention. In particular, FIGS. 1 and 2 show the schematic shape of the connecting rod 1 to be manufactured, and FIGS. 3 to 6 show the mold structure and its behavior for warm forging as a closed forging device used for manufacturing the connecting rod 1. Each is shown.

  The connecting rod 1 has a large end portion 2 and a small end portion 3 as well as a rod-like or shaft-like connecting rod portion 4 that connects both of them. The large end 2 is formed with a half-divided and semicircular bearing recess 5, which is not shown in the drawing and is abutted against the butting surface (divided surface) which is the end surface 2 a of the large end 2. It is rotatably connected to a crankpin portion of a crankshaft (not shown) via a circular bearing cap and a bearing metal. On the other hand, a pin hole 4 is formed in the small end portion 3 and is connected to the piston via a piston pin (not shown) inserted into the pin hole 4.

  The bearing recess 5 having a semicircular shape means a shape when the bearing recess 5 is viewed from the axial direction (axial direction of the crank pin portion to which the connecting rod 1 is assembled). Further, the pin hole 4 shown in FIG. 1 has an incomplete shape after forging and before machining.

  As shown in FIGS. 1 and 2, ribs 6 are formed in a closed loop shape so as to include both ends in the width direction on both the front and back surfaces of the connecting rod portion 4. As a result, the connecting rod portion 4 itself is formed to have a substantially H-shaped cross section, and the width dimension W of the groove 7 formed between the ribs 6 and 6 is maximum at the portion near the large end portion 2. It has become.

  3 to 6 show a mold structure for warm forging as a closed forging device used for manufacturing the connecting rod 1 and its behavior. As shown in FIG. 3, the mold 10 is roughly divided into a die case 11 that functions as a rectangular outer frame, a pair of left and right closing dies (divided molds) 12 inserted into the die case 11, and A punch holder 13 that applies a pressing force (pushing force) to the die case 11 to the closing die 12 and a large end punch 14 that is supported by the punch holder 13 so as to be relatively movable (movable up and down) are provided.

  The die case 11 has two inclined surfaces (tapered surfaces) 15a in the central square hole-shaped die receiving portion 15 and is accommodated or inserted into the die receiving portion 15. The pair of left and right closing dies 12 have inclined cam surfaces (taper surfaces) 12a on the back side corresponding to the inclined cam surface 15a on the die case 11 side. Thereby, the die case 11 substantially functions as an outer mold, and the pair of closing dies 12 accommodated in the die case 11 function as inner molds.

  Then, when the pair of closing dies 12 is pushed into the die case 11 with the rolling force exerted on the punch holder 13 by the forging press machine, the pair of closings are caused by sliding contact between the inclined cam surfaces 12a and 15a as shown in FIG. The dies 12 and 12 move toward each other. In addition, from the function of the die case 11, it is desirable that the die case 11 as the outer mold is formed of a material harder than the pair of left and right closing dies 12 as the inner mold.

  The abutment surfaces (die-parting surfaces) of the pair of left and right closing dies 12 are engraved with halved impression portions corresponding to the shape of the connecting rod 1 that is a product, and these impression portions are preheated, for example. A pair of closing dies 12 is accommodated or inserted into the die case 11 in a state where the stepped rod-shaped material (blank) 16 is inserted. In addition, since the rod-shaped raw material 16 is preformed in a stepped shape in the previous step, it should be called a so-called preform (preliminary molded body).

  Then, as described above, when the pair of closing dies 12, 12 are moved closer to each other by sliding contact between the inclined cam surfaces 12a, 15a, the closing dies 12, 12 are eventually brought into contact with each other, as shown in FIG. The so-called mold clamping state is obtained. At this point in time, the closing die 12 reaches the bottom dead center for the die case 11 for the first time, and the pushing of the closing die 12 into the subsequent die case 11 becomes impossible.

  In the process of reaching the clamped state, the material 16 is forged into the rough shape of the connecting rod 1, and in the clamped state, the impression portion is incomplete but hermetically sealed and the material meat is filled. Even when both of the closing dies 12 reach the bottom dead center and are in a mold-clamping state, an opening through which the large end punch 14 can be inserted is secured on the upper surface of both of the closing dies 12.

  As described above, when both the closing dies 12 reach the bottom dead center and are in the clamping state, the large end punch 14 supported by the punch holder 13 is eventually forged as shown in FIGS. Under the pressing force of the press machine, it descends and is pushed into the impression part. As a result, the large end portion 2 including the bearing recess 5 (see FIG. 1) is installed in the longitudinal direction in the vicinity of the large end portion 2 (see FIG. 1) having a relatively large volume among the raw materials 16, particularly the raw material 16. The neighborhood is upset.

  As is clear from the above description, the large end punch 14 has an abutment surface (divided surface) which is the end surface 2a (see FIG. 1) of the large end 2 in addition to the bearing recess 5 in addition to the above-described upsetting function. ) Is finished into a predetermined shape. By such upsetting by the large end punch 14, the shape accuracy of the connecting rod 1 is enhanced in the form of so-called closed forging, and the rough forging of the connecting rod 1 is completed. In the present embodiment, even if it is closed forging, the occurrence of a part of “burr” in the closed closed space is allowed.

  Here, as described above, the punch for the large end portion which is responsible for forming the butting surface (divided surface) which is the end surface 2a of the large end portion 2 in addition to the bearing concave portion 5 together with the upsetting function of the large end portion 2. As shown in FIGS. 7 and 8, the portion that is responsible for forming the deepest portion of the bearing recess 5 in the large-end punch 14 is a flat pressure restraining surface 18. 7 and 8 show an example in which forging is performed in a shape in which the bearing recess 5 is provided with the fillet 17.

  Further, as described above with reference to FIGS. 1 and 2, the connecting rod portion 4 itself has a substantially H-shaped cross section because ribs 6 protrude from both the front and back surfaces of the connecting rod portion 4 of the connecting rod 1. The width dimension W of the groove 7 formed between the ribs 6 and 6 is the largest in the portion near the large end portion 2. Therefore, as the relationship between the width dimension P of the flat bottom pressure restraint surface 18 shown in FIG. 8 and the maximum dimension W1 of the width dimension W of the groove 7, the width dimension P of the bottom pressure restraint surface 18 is It is preset so as to be larger than the maximum width dimension W1.

  Accordingly, when the large end 2 is installed using such a large end punch 14 as shown in FIGS. 7 and 8, the shape of the bottom pressure restraining surface 18 is transferred. The upsetting is completed in a state in which the entire inner peripheral surface of the half-shaped bearing recess 5 including the flat surface 5a to be shaped and the end surface 2a of the large end 2 serving as the split surface of the bearing recess 5 are pressure restrained. However, the bearing recess 5 does not have a semicircular shape as shown in FIG. 1 because it includes the flat surface 5a, but the deepest portion of the bearing recess 5 when the bearing recess 5 is viewed from its axial direction. It is nothing but to complete the upsetting while maintaining the incomplete recess shape whose side becomes the flat surface 5a.

  Therefore, as shown in FIG. 9, the flow direction m <b> 1 of the raw material meat during the upsetting by the large end punch 14 is directed to the bottom pressure restraint surface 18 (the bottom pressure restraint surface 18. The flat surface 5a) formed by the step is oriented in a direction perpendicular to the surface, and a portion having a step in the connecting portion between the large end portion 2 and the connecting rod portion 4 having a relatively large volume is positively filled. become able to. Therefore, it is possible to prevent the occurrence of forging defects such as a lack of thickness at the joint portion. This tendency is preset as P> W1 as the relationship between the width P of the flat bottom pressure restraint surface 18 shown in FIG. 8 and the maximum width W1 of the groove 7 between the ribs 6 and 6. This becomes even more noticeable.

  In addition, as shown in FIGS. 3 to 6, the pair of left and right closing dies 12 having an impression portion is pushed into the die case 11 and forged, so that the closing dies 12, 12 can be easily aligned. At the same time, a target shape can be obtained with high accuracy when the closing dies 12, 12 are put together, and as a result, the impression processing of the impression portion of each closing die 12 is facilitated.

  Here, when the bearing recess 5 is viewed from its axial direction, the upsetting is completed with the incomplete recess shape in which the deepest side of the bearing recess 5 becomes the flat surface 5a. This means that the shape does not become a regular semicircular shape but remains as an incomplete shape as the bearing recess 5. Therefore, when the connecting rod 1 formed by closed forging is machined in a subsequent process, the deepest side than the flat surface 5a is cut out in a substantially crescent shape together with the meat 17 as shown in FIG. Thus, it can be finished as a regular semicircular bearing recess 5.

  10 and 11 show an outline of a forging system premised on the use of the mold structure shown in FIGS. 3 to 6, in particular FIG. 10 shows a plan view thereof and FIG. 11 shows a front view thereof. .

  In this system, the die case 11 as the outer die described above is fixed to the forging press 8 in a fixed position in order to improve the productivity in the closed forging of the so-called single-piece (strike) type connecting rod 1. On the other hand, a pair of left and right closed dies 12 as inner molds that can be attached to and detached from the die case 11 are set as one set in the die case 11 and closed forging is performed. Then, the closing die 12 is taken out of the die case 11 together with the connecting rod 1 after forging for each forging, and replaced with another pair of left and right closing dies 12. In the following description regarding FIGS. 10 and 11, a set of the pair of left and right closing dies 12 is referred to as an inner mold 112 for convenience.

  As shown in FIGS. 10 and 11, a rotary index type and multi-station type storage device 21 having a rotary table 20 as a main element is adjacent to the forging press 8 in the vicinity of the forging press 8. In addition, a handling robot 22 as a conveying means is arranged between the forging press 8 and the storage device 21. The rotary table 20 is indexed and rotated in the direction of arrow M in FIG. 10 by a predetermined index driving mechanism (not shown) in synchronism with the forging molding cycle of the forging press 8.

  As described above, the storage device 21 is used as a standby area or a circulation type storage area for waiting for a plurality of inner dies 112 to be kept in standby every time forging is performed. Will work. At the same time, it also functions as a stage for performing regular maintenance for removing the scale of the inner mold 112, applying a lubricant, and the like.

  On the rotary table 20, a mold preheating station S1, a mold lubrication station S2, a blank mold setting station S3, a mold loading / unloading station S4, a workpiece unloading station S5, a mold cleaning station S6, and a mold damage check Each station (stage) of the station S7 is set.

  A mold preheating device 23 is prepared at the mold preheating station S1, and the inner mold 112 is heated to about 60 ° C. to 100 ° C., for example. When the rotary table 20 is indexed to the mold preheating station S1, the inner mold 112 sent from the previous station is taken into the mold preheating apparatus 23, while the inner mold 112 already heated by the mold preheating apparatus 23 is taken. Transfer on the rotary table 20. In this mold preheating device 23, it is assumed that at least one of the inner molds 112 after completion of preheating is waiting separately from the inner mold 112 preheated by the mold preheating apparatus 23.

  In the mold lubrication station S2, a lubricant is applied to the impression portion of the inner mold 112 indexed to the mold lubrication station S2. This lubricant application operation may be performed by an automated device or manually.

  In the blank mold charging station S3, a blank (preform) as the material 16 is loaded into the impression part of the inner mold 112 to which the lubricant has been previously applied. The blank is preheated to a temperature suitable for warm forging. The blank is inserted into the inner mold 112, that is, the impression part which is a gap between the closing dies 12 and 12 set as a pair on the left and right sides, and the blank is abutted so as not to be displaced. Shall.

  In the mold loading / unloading station S4, after the forging molding cycle for each cycle on the forging press 8 side is finished, the inner mold 112 (the inner mold 112 is moved to the left and right) from the die case 11 shown in FIGS. As described above, the paired closing dies 12 are taken out by the handling robot 22 and transferred to the rotary table 20. The inner die 112 still contains the connecting rod 1 as a forged product formed by forging. Then, after the rotary table 20 has been indexed and rotated, the inner die 112 on which a blank has been set in advance is set in the die case 11 on the forging press 8 side by the handling robot 22.

  Here, as shown in FIG. 11, since the movable lubricant application device 24 is attached to the forging press 8 side, the inner mold 112 is taken out from the die case 11 and the next Before the inner mold 112 is set, a lubricant is applied by, for example, a spray method around the sliding surface of the die case 11 with the inner mold 112. On the forging press 8 side where the new inner die 112 is set in the die case 11, the next forging molding cycle can be immediately started.

  At the workpiece take-out station S5, the inner die 112 is opened and the forging-formed connecting rod 1 is taken out.

  In addition, a mold cleaning machine 25 is prepared at the mold cleaning station S6. For example, cleaning using an air nozzle, a wire brush, or the like, particularly for the purpose of removing scales or the like adhering to the compression portion of the inner mold 112. Is done. When the rotary table 20 is indexed to the mold cleaning station S6, the inner mold 112 sent from the previous station is taken into the mold cleaning machine 25 by the handling robot 26, while being already cleaned by the mold cleaning machine 25. The inner mold 112 is transferred onto the rotary table 20. It is assumed that at least one of the inner molds 112 after completion of cleaning is waiting in the mold cleaning machine 25 separately from the inner mold 112 cleaned by the mold cleaning machine 25.

  In the mold damage confirmation station 7, in addition to visual inspection and hammering inspection by an operator, there is an abnormality such as cracking of the inner mold 112 using, for example, an AE (acoustic emission) type flaw detection device. Perform an inspection. When an abnormality is found, the corresponding inner mold 112 is extracted from the rotary table 20, while a new inner mold or a spare internal mold that has been maintained is put in the rotary table 20 instead.

  By performing the operations at the stations S1 to S7 in the storage device 21 in synchronization with the forging molding cycle on the forging press 8 side, the forging press 8 side only repeats a predetermined forging molding cycle, Even in the forging of the so-called single-piece connecting rod 1, since the downtime on the forging press 8 side is significantly shortened, efficient closed forging with high productivity can be performed.

  In other words, in addition to blank insertion and removal of the connecting rod 1 after forging, all auxiliary work such as cleaning of the inner mold 112 and application of lubricant are performed outside the forging press 8. Therefore, the time required for these auxiliary operations does not affect the forging molding cycle on the forging press 8 side, and productivity can be improved by shortening the forging molding cycle time.

  Further, if the slide down stroke of the forging press 8 is constant and the outer shapes of the die case 11 and the inner mold 112 are made common, it is possible to easily and flexibly cope with small-quantity production of other types. .

  Here, individual effects other than those described above are listed as follows.

  (1) Since this is a system in which only the inner mold 112 (a pair of left and right closed dies 12) is replaced each time, leaving the die case 11 as an outer mold, compared with a system in which the entire mold including the die case 11 is replaced. The equipment can be downsized.

  (2) Forging is performed with the fresh inner mold 112 that has been cleaned each time, so that the quality and stability of the forged product can be improved.

  (3) By preheating the inner mold 112 in advance, it is possible to improve and stabilize the quality of the forged product as described above.

  (4) The inner die 112 is checked for damage each time, and the inner die 112 is replaced as necessary, so that even if the inner die 112 is damaged, the forging press 8 is not stopped. It can respond and production can be continued. This also improves productivity.

1 ... Connecting rod (forged product)
8 ... Forging press 11 ... Die case (outer mold)
12 ... Blocking die (inner mold)
16 ... Material 20 ... Rotary table 21 ... Storage device (standby area, circulation type storage area)
22 ... Handling robot (conveying means)
S1 ... Mold preheating station S2 ... Mold lubrication station S3 ... Blank mold setting station S4 ... Mold loading / unloading station S5 ... Work removal station S6 ... Mold cleaning station S7 ... Mold damage confirmation station

Claims (11)

  A forging method characterized in that a die is set in a forging press machine so that the die can be attached and detached, the die is forged, and the die is removed from the forging press machine and replaced with another die for each forging process. .   2. The forging method according to claim 1, wherein a die to be charged next is made to wait in a waiting area adjacent to the forging press. The mold has a pair of inner molds that can approach and separate in the horizontal direction and an outer mold that accommodates the inner molds, and the outer molds are separated from each other based on the rolling force of the forging press. It is designed to drive in the mold clamping direction
3. The forging method according to claim 2, wherein the inner die is taken out of the forging press together with the forged product after forging and replaced with another inner die for each forging. A forging system for use in the forging method according to claim 3,
The standby area is a circular storage area having a plurality of stations,
This storage area includes a station that manages the maintenance of the inner mold.   The forging system according to claim 4, wherein each of the stations that manages the cleaning of the inner mold and the application of the lubricant is included as the station that manages the maintenance.   6. The forging system according to claim 5, wherein the storage area includes respective stations for taking out a forged product after forging from the inner die and feeding the material into the inner die.   The forging system according to claim 6, wherein the storage area includes a station for preheating the inner mold.   8. The forging system according to claim 7, further comprising conveying means for carrying in and out of the inner mold between the forging press and the storage area.   9. The forging system according to claim 8, wherein the storage area is configured as a multi-station type having a rotary table as a main element.   The forging system according to any one of claims 4 to 9, wherein the die forging is closed forging, and the inner die is for closed forging.   The forging system according to any one of claims 4 to 10, wherein the outer mold is made of a material harder than the inner mold.

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