JP7669604B2 - Die rotation device and forging machine - Google Patents

Description

The present invention relates to a die rotation device that rotates either a fixed die or a movable die that are arranged opposite each other, and to a forging machine that is equipped with this die rotation device.

In a typical pressing machine, a die (fixed die) and a punch (movable die) arranged opposite each other work together to perform pressing processing on a workpiece, causing plastic deformation to produce a part of a desired shape. One configuration example of this type of pressing machine is disclosed in Patent Document 1. The horizontal continuous multi-stage pressing machine of Patent Document 1 comprises a ram that can move forward and backward freely in a first direction, a number of punches arranged in a second direction of the ram, a number of dies that are fixedly arranged in the second direction and correspond to each of the multiple punches, and a transfer unit that transports the workpiece.

JP 2018-8281 A

In order to stabilize the operation of the transfer unit in transporting the workpiece, it may be preferable to change the posture of the workpiece after the heading process, rather than maintaining the posture. For example, the risk of the workpiece dropping may be reduced by changing the posture of the workpiece to suit the shape and operating form of the fingers that grip the workpiece, while taking into account the position of the center of gravity of the workpiece and the gripping position. However, with conventional heading machines, it is difficult to change the posture of the workpiece protruded from the die immediately before it is gripped. For this reason, a technology is required that rotates the die holding the workpiece around its central axis and changes the posture of the workpiece together with the die.

In addition, the technology of rotating a die around its central axis is not limited to applications in which a die is rotated or the position of a workpiece is changed, but it is possible to modify the configuration or apply it to other applications. For example, the object to be rotated may be a punch instead of a die. Also, for example, by rotating the die, it is possible to perform cutting or twisting operations on the workpiece.

The present invention was made in consideration of the problems in the background art described above, and aims to provide a die rotation device that can be used for work purposes other than forging work by rotating either a fixed die or a movable die that are arranged opposite to each other, and a forging machine equipped with this die rotation device.

The die rotation device of the present invention includes a fixed die having a central axis and holding a workpiece, a movable die arranged in a direction in which the central axis extends and facing the fixed die, and performing a predetermined operation on the workpiece in cooperation with the fixed die, and a rotation drive mechanism that rotates a rotating die, which is either the fixed die or the movable die, around the central axis, and the rotation drive mechanism includes an operating member that can move in the direction in which the central axis extends while sharing the central axis, a spiral groove provided in one of the rotating die and the operating member so as to be inclined with respect to the central axis, and a spiral groove provided in the other of the rotating die and the operating member so as to be inclined with respect to the central axis. the rotating mold has a guide pin that engages with the spiral groove, a drive unit that drives the operating member in the extension direction of the central axis to move the guide pin relatively along the spiral groove, thereby rotating the rotating mold, and a rotation prevention unit that prevents the operating member from rotating around the central axis, wherein the rotation prevention unit has a flat portion formed on the outer peripheral surface of the cylindrical operating member that is arranged on the outer periphery of the rotating mold, and extends in the extension direction of the central axis and in a width direction perpendicular to the extension direction, and a rotation prevention body that extends in the width direction and is in contact with the flat portion in the width direction while the operating member moves in the extension direction of the central axis .

The pressing machine of the present invention further comprises three or more pressing steps, each of which includes a fixed die and a movable die, and in which the workpiece is transported in sequence; a main drive source that causes the movable die to reciprocate along the central axis to perform pressing processing on the workpiece ; a fixed die having the central axis and holding the workpiece; a movable die that is positioned in a position in the extension direction of the central axis, faces the fixed die, and performs a predetermined operation on the workpiece in cooperation with the fixed die; and a rotation drive mechanism that rotates a rotating die, which is either the fixed die or the movable die, about the central axis, and a die rotation device that rotates the rotating die at least one of the forward and backward movements of the movable die , wherein the die rotation device is provided in the pressing step midway, and performs a posture change operation to change the rotational posture of the workpiece about the central axis instead of the pressing processing operation, and transports the workpiece after the posture change to the downstream pressing step .

In the die rotation device and forging machine of the present invention, the rotation drive mechanism can rotate either the fixed die or the movable die around the central axis, so that die rotation can be applied to work applications other than forging processing work.

1 is a plan view showing a schematic overall configuration of a pressing machine to which a die rotation device of a first embodiment can be applied. FIG. 4 is a side cross-sectional view showing the configuration of a die, which corresponds to a rotary die of a die rotating device, and a rotary drive mechanism. FIG. FIG. 2 is an enlarged perspective view of a portion of the mold rotating device as viewed obliquely from below. 1 is a perspective view illustrating an example of the shape and posture of a workpiece in each process produced by a multi-process heading machine; 5 is a time chart illustrating the operation when the posture of the workpiece is changed by the die rotation device in the third forging process of the forging machine shown in FIG. 4. 13 is a diagram showing a schematic configuration example of a die rotation device according to a second embodiment, in which a punch corresponding to a rotating die performs cutting work on a workpiece. FIG. FIG. 7 is a time chart illustrating the operation of the configuration example of FIG. 6. 13 is a diagram showing a schematic configuration example of a die rotation device according to a third embodiment for performing a twisting operation on a workpiece; FIG. 9 is a diagram showing the shape of a part manufactured by the configuration example of FIG. 8.

1. Overall Configuration of the Forging Machine 1 First, the overall configuration of the forging machine 1 to which the die rotation device 5 of the first embodiment can be applied will be described with reference to FIG. 1 and FIG. 2. The forging machine 1 is a horizontal multi-step forging machine. The forging machine 1 is composed of a frame 2, a ram 3, five sets of punches 41 and dies 44, a workpiece transport unit 49, and a main drive unit 9. The forging machine 1 performs forging processing of the workpiece W in the first to fifth forging steps composed of the five sets of punches 41 and dies 44. The punch 41 is another name for a movable die, and the die 44 is another name for a fixed die. In FIG. 1, the first to fifth forging steps are arranged from the top to the bottom. The number of forging steps of the forging machine 1 is not limited to five steps, but is in the range of about 1 to 8 steps.

The frame 2 is a housing for arranging each part, and is made of iron to be sturdy. The five die holders 21 are arranged in a line in the width direction of the frame 2. The five dies 44 are replaceably attached to the front side (left side in Figure 1) of each die holder 21. A predetermined processing die is formed in front of each die 44. The die 44 has a central axis CL (see Figure 2), and holds the workpiece W in the processing die.

The ram 3 is roughly rectangular in plan view and reciprocates in the front-rear direction (left-right direction in FIG. 1) with respect to the frame 2. The five punch holders 31 are arranged side by side in the width direction on the front side of the ram 3 (right side in FIG. 1). The five punches 41 are replaceably attached to the front side of each punch holder 31. A predetermined processing die is formed on the front side of each punch 41. Each punch 41 reciprocates together with the ram 3. The punch 41 is disposed at a position in the extension direction of the central axis CL and faces the die 44. The punch 41 performs a forging process on the workpiece W in cooperation with the die 44. Note that the work performed by the punch 41 and the die 44 in cooperation is not limited to forging using a processing die, and may be other work.

The forging machine 1 is equipped with a cutting mechanism (not shown). The cutting mechanism has a ring-shaped movable cutter, a wire feed mechanism, and a pusher mechanism. The movable cutter cuts the long wire inserted into the ring by the wire feed mechanism to create a cylindrical workpiece of specified dimensions. The pusher mechanism pushes the workpiece out of the movable cutter. Examples of materials for the wire and workpiece include aluminum, iron, and various alloys.

The work transport unit 49 is disposed from above the die holder 21 to the front of the die 44. The work transport unit 49 is sometimes referred to as a transfer device. The work transport unit 49 has six pairs of fingers that grip the work. The first pair of fingers at the most upstream position grips the work produced by the cutting mechanism and transports it to the first forging process. The second to fifth pairs of fingers grip the work at the upstream forging process and transport it to the downstream forging process. The sixth pair of fingers at the most downstream position grips the work at the fifth forging process and transports it to the unloading unit (not shown).

A main drive unit 9 is provided to reciprocate the ram 3. The main drive unit 9 is composed of a main drive source 91 and various transmission mechanisms and cam mechanisms. The main drive source 91 can be, for example, an induction motor or a synchronous motor that operates on a three-phase AC power source. The main drive unit 9 drives the work transport unit 49 and the cutting mechanism unit together. The driving force of the main drive source 91 is input to a crankshaft 95 that drives the ram 3 via a flywheel 92, a disc brake 93, and a reduction mechanism 94. Furthermore, the driving force is branched and transmitted from the crankshaft 95 to a side shaft 97 via a branch gear pair 96.

The side shaft 97 branches and transmits the driving force upward. The driving force branched upward rotates and drives the transfer cam 98. The transfer cam 98 drives the work transport section 49. In addition, six open-close cams 9A are connected to the side shaft 97 via the transfer drive 99 so that they are rotated and driven. The open-close cams 9A are arranged at equal intervals in the width direction. Each open-close cam 9A drives the finger pairs to open and close.

The side shaft 97 is further provided with a cutter cam 9B, and is connected to a pusher cam 9C, a feed cam 9D, a wire rod feed device 9E, and five kick-out cams 9F. The cutter cam 9B, pusher cam 9C, feed cam 9D, and wire rod feed device 9E drive the cutting mechanism. The kick-out cams 9F are arranged at equal intervals in the width direction, and correspond to the positions of the first to fifth forging processes, respectively. The kick-out cams 9F drive the kick-out pins 4A, which will be described later.

2. Configuration in the Vicinity of the Die 44 Next, the configuration in the vicinity of the die 44 will be described with reference to Fig. 2. For convenience, the right side of Fig. 2 is the front side, and the left side is the rear side. As shown in the figure, the die holder 21 is configured by connecting a holder member 211, a back plate 212, and a die frame 213 from the front side to the rear side. These three members are each formed in a cylindrical shape that shares a central axis CL extending in the front-rear direction. Furthermore, these three members are joined by being pressed in the front-rear direction.

The cylindrical holder member 211 has a step on its inner circumferential surface, and the inner diameter is large at the front end and in the range from the middle position to the rear end. A thrust bearing 214 is provided at the front end of the holder member 211 where the inner diameter is large. A rotation operation space 215 is defined at the rear of the holder member 211 where the inner diameter is large. The cylindrical back plate 212 is formed so that its inner diameter is smaller than the outer diameter of the die 44. The cylindrical die frame 213 is formed so that the inner diameter is large at the front and small at the rear.

The die 44 is held between the thrust bearing 214 and the back plate 212 so that it cannot move in the front-rear direction. The die 44 is held rotatably around the central axis CL inside the holder member 211. A thrust bearing may be provided on the front side of the back plate 212 to reduce friction when the die 44 rotates. The die 44 holds the workpiece W inside a processing die formed on the front side. The shape of the processing die can be changed in various ways, so illustrations and explanations of the specific shape are omitted. The die 44 is formed in a roughly cylindrical shape, and a kick-out pin 4A is inserted into the inside from the rear.

The kick-out pin 4A performs an ejection operation to eject the workpiece W, which has undergone heading processing, from the die 44. The kick-out pin 4A is arranged on the central axis CL and is supported so as to be movable in the front-rear direction. The kick-out pin 4A is formed in a stepped round bar shape with several points where the diameter size changes. The tip 4C of the kick-out pin 4A can enter the rear of the die 44 and abut against the workpiece W. The tip 4C of the kick-out pin 4A may serve as part of the processing mold for the die 44.

The kick-out pin 4A has a large-diameter flange 4B toward the rear. The part of the kick-out pin 4A rearward of the flange 4B is housed inside the approximately cylindrical neck adjustment screw 4F. The kick-out pin 4A has its retracted position determined by the flange 4B abutting against the neck adjustment screw 4F. The neck adjustment screw 4F is screwed into a frame 841 (described below), and its position is adjusted in the front-rear direction. This adjusts the retracted position of the kick-out pin 4A. The rear end 4D of the kick-out pin 4A is driven by the main drive source 91 via a kick-out cam 9F.

While the punch 41 approaches the die 44 and the heading operation progresses, the kick-out pin 4A maintains the retracted position shown in FIG. 2. As the heading operation is completed and the punch 41 moves away from the die 44, the kick-out pin 4A is driven to the forward position by the kick-out cam 9F, and pushes the workpiece W to the front side of the die 44. The kick-out pin 4A is then pushed backward by the biasing spring 4E, which will be described later, and returns to the retracted position while following the kick-out cam 9F.

3. Configuration and operation of the die rotation device 5 of the first embodiment Next, the configuration and operation of the die rotation device 5 of the first embodiment will be described with reference to Figs. 2 and 3. The die rotation device 5 is applicable to at least one forging process of the forging machine 1. The die rotation device 5 is composed of a die 44, a punch 41, a rotation drive mechanism 6, and the like. The rotation drive mechanism 6 rotates a rotary die, which is either the die 44 or the punch 41, around the central axis CL. In the first embodiment, the rotation drive mechanism 6 rotates the die 44, which is the rotary die, to cause the die 44 to perform a posture change operation for changing the posture of the workpiece W. The rotation drive mechanism 6 is composed of an operation member 61, a spiral groove 62, a guide pin 63, a rotation prevention unit 7, a drive unit 8, and the like.

In FIG. 3, the lower half of the die 44 and the operating member 61 are shown, with the upper half omitted. The operating member 61 is formed in a cylindrical shape and is disposed on the outer periphery of the die 44. The inner diameter of the operating member 61 is set to be the same as the outer diameter of the die 44 with a positive tolerance, or to be slightly larger than the outer diameter of the die 44. As shown in FIG. 2, the operating member 61 is disposed in the rotation operation space 215 inside the holder member 211. The operating member 61 is movable in the extension direction of the central axis CL while sharing the central axis CL.

The spiral groove 62 is provided on the operating member 61 so as to be inclined with respect to the central axis CL, as shown in FIG. 3. The spiral groove 62 is formed in a straight line so as to have a constant inclination angle with respect to the central axis CL. Alternatively, the spiral groove 62 may be formed in a curved line so that the inclination angle gradually changes. The inclination angle and groove length of the spiral groove 62 are determined so as to correspond to the desired rotation angle range for rotating the die 44. In the first embodiment, the spiral groove 62 is formed so as to correspond to a rotation angle range of 25° of the die 44. The spiral groove 62 is preferably provided at multiple locations in the circumferential direction of the operating member 61. In the first embodiment, the spiral groove 62 is provided at two side positions 180° apart in the circumferential direction of the operating member 61.

The guide pins 63 are cylindrical members that are erected radially outward on the outer peripheral surface of the die 44. The number of guide pins 63 is the same as the number of spiral grooves 62. Each guide pin 63 engages with a different spiral groove 62. The length of the guide pins 63 is set to match the groove depth of the spiral groove 62 or to be slightly larger than the groove depth. The diameter of the guide pins 63 is set to be slightly smaller than the groove width of the spiral groove 62. This stabilizes the engagement state of the guide pins 63 with the spiral groove 62.

The rotation prevention portion 7 prevents the operating member 61 from rotating around the central axis CL. The rotation prevention portion 7 is preferably provided at multiple locations in the circumferential direction. In the first embodiment, the rotation prevention portion 7 is provided at two locations, on the lower and upper sides of the operating member 61 (see FIG. 2). The rotation prevention portion 7 consists of a flat portion 71 and a rotation prevention body 72. The flat portion 71 is provided on the outer peripheral surface of the operating member 61 and is formed, for example, by cutting. The flat portion 71 is a roughly rectangular flat portion that extends in the extension direction of the central axis CL and in the width direction perpendicular to the extension direction.

The rotation prevention body 72 is formed of a round bar-shaped member extending in the width direction. Both ends of the rotation prevention body 72 are fixed to the inner peripheral surface of the holder member 211. The rotation prevention body 72 is always in contact with almost the entire width direction of the flat portion 71 while the operating member 61 moves in the extension direction of the central axis line CL. This prevents the operating member 61 from rotating, stabilizing the rotational movement of the die 44, which will be described later. Furthermore, the combination of multiple sets of spiral grooves 62 and guide pins 63, as well as the multiple rotation prevention parts 7 arranged alternately in the circumferential direction, facilitates the rotational movement of the die 44.

The drive unit 8 drives the operating member 61 in the direction in which the central axis CL extends (the front-rear direction). The drive unit 8 is composed of a number of operating pins 81, a drive pin 83, a drive source unit 84, a liquid source container 8A, a liquid path operating unit 8B, a hydraulic fluid control unit 8C, and a plate position detection unit 8D.

The multiple operation pins 81 are positioned equidistant from the central axis CL and are arranged at equal intervals in the circumferential direction. The multiple operation pins 81 extend parallel to the central axis CL and are arranged so as to pass through the through holes 216 of the back plate 212. Six operation pins 81 are illustrated in FIG. 3. The front end of each operation pin 81 is connected to the rear end of the operation member 61. The rear end of each operation pin 81 is connected to a flange-shaped flange portion 82.

A coil-shaped biasing spring 4E is inserted between the flange 82 and the flange 4B of the kick-out pin 4A. The biasing spring 4E biases the kick-out pin 4A rearward. A cylindrical drive pin 83 is disposed on the outer periphery of the biasing spring 4E. The front end of the drive pin 83 is connected to the flange 82. The rear end of the drive pin 83 is connected to a connection plate 842 (described below).

The drive source unit 84 is disposed on the rear side of the die frame 213 of the die holder 21. The drive source unit 84 is composed of a frame body 841, two hydraulic drive sources 85, two sets of front and rear fluid paths 88 and 89, and a connecting plate 842. Note that since the desired operating force cannot be obtained with one hydraulic drive source 85, two hydraulic drive sources 85 are used in parallel. The frame body 841 is a hollow frame-shaped member that opens to the front, and is disposed in contact with the rear side of the die frame 213.

The two hydraulic drive sources 85 are provided toward the rear inside the frame 841. The two hydraulic drive sources 85 are spaced apart and vertically symmetrical when viewed from the central axis CL. The underhead adjustment screw 4F is located between the two hydraulic drive sources 85.

Each hydraulic drive source 85 has a cylinder 86 and a piston 87. The cylinder 86 is formed in a cylindrical shape with a bottom that opens to the front. The piston 87 is disposed inside the cylinder 86 and protrudes to the front. The piston 87 is a round bar-shaped member consisting of a small diameter portion at the front and a large diameter portion at the rear. A liquid-tight groove and an O-ring (symbol omitted) are provided on the outer periphery of the large diameter portion. This forms a liquid-tight structure between the cylinder 86 and the piston 87.

The connecting plate 842 is formed long in the vertical direction. As shown in FIG. 2, the connecting plate 842 is connected to the front sides of the two pistons 87 using bolts 843. The neck adjustment screw 4F is loosely fitted into a hole provided in the center of the connecting plate 842. The rear end of the drive pin 83 is connected to the front side of the connecting plate 842. Therefore, the two pistons 87, connecting plate 842, drive pin 83, operating pin 81, and operating member 61 move integrally in the front-to-rear direction.

The closed space defined by the outer surface of the small diameter portion of the piston 87 and the inner surface of the cylinder 86 is the front liquid chamber 861. The closed space defined by the rear surface of the piston 87 and the inner bottom surface of the cylinder 86 is the rear liquid chamber 862. A front communication port 863 is provided through the side surface of the cylinder 86, communicating with the front liquid chamber 861 from the outside. Similarly, a rear communication port 864 is provided through the side surface of the cylinder 86, communicating with the rear liquid chamber 862 from the outside.

The front communication port 863 is connected to the liquid source container 8A via the front liquid path 88 and the liquid path operation unit 8B. The rear communication port 864 is connected to the liquid source container 8A via the rear liquid path 89 and the liquid path operation unit 8B. The front liquid path 88 and the rear liquid path 89 of the two hydraulic drive sources 85, in other words the four liquid paths, are of equal length and equal cross-sectional area. This results in good agreement in the operating characteristics when the two hydraulic drive sources 85 operate in synchronous. The front liquid path 88 and the rear liquid path 89 are made of resin tubes, metal pipes, etc. An example of the hydraulic fluid used in the hydraulic drive source 85 is hydraulic oil, but is not limited to this.

The liquid path operation unit 8B is composed of a combination of pumps and valves (not shown). The liquid path operation unit 8B operates the flow of hydraulic fluid between the two hydraulic drive sources 85 and the liquid source container 8A. The hydraulic fluid control unit 8C controls the operation of the liquid path operation unit 8B. The hydraulic fluid control unit 8C is composed, for example, of a computer device with a function for inputting and outputting control signals. The hydraulic fluid control unit 8C is accompanied by a plate position detection unit 8D.

The plate position detection unit 8D detects the position of the coupling plate 842 in the front-rear direction. The plate position detection unit 8D is composed of an encoder 8E and a linear gauge 8F. The linear gauge 8F is provided on the top of the coupling plate 842 and moves back and forth together with the coupling plate 842. The linear gauge 8F has a scale engraved at a predetermined pitch in the front-rear direction. The encoder 8E is fixedly attached to the frame 841 and disposed opposite the linear gauge 8F. The encoder 8E reads and codes the scale of the linear gauge 8F, and outputs it to the hydraulic fluid control unit 8C. For example, a magnetic detection type sensor can be used as the plate position detection unit 8D.

The hydraulic fluid control unit 8C receives the output of the encoder 8E and also receives information regarding the operating status of the main drive source 91. The hydraulic fluid control unit 8C determines the current position of the operating member 61 based on the output received from the encoder 8E. The hydraulic fluid control unit 8C also refers to the operating status of the main drive source 91 and controls the fluid path operating unit 8B in a timely manner to control the operation of the operating member 61.

In FIG. 2, the front fluid chamber 861 has the maximum volume, and the rear fluid chamber 862 has the minimum volume. At this time, the piston 87 is in the retracted position. When hydraulic fluid flows out of the front fluid chamber 861 and into the rear fluid chamber 862 under the control of the hydraulic fluid control unit 8C, the piston 87 moves forward by an amount of movement corresponding to the amount of hydraulic fluid flowing in and out. Conversely, when hydraulic fluid flows out of the rear fluid chamber 862 and into the front fluid chamber 861, the piston 87 moves backward. The operating member 61 moves forward and backward in synchronization with the forward and backward movements of the piston 87.

If the inflow and outflow of hydraulic fluid in one hydraulic drive source 85 precedes the outflow of hydraulic fluid, the operating force output to the connecting plate 842 will momentarily be only one side. At this time, the operating member 61 will not operate, or will operate at a slow speed. Then, the inflow and outflow of hydraulic fluid in the other hydraulic drive source 85 will catch up in a short time, and operating forces will be output from both hydraulic drive sources 85 to the connecting plate 842. After this, the two hydraulic drive sources 85 operate in synchronization. Therefore, the operating forces output from the two hydraulic drive sources 85 are added together, and the operating member 61 can exert a large operating force.

As shown by arrow M1 in FIG. 3, when the operating member 61 advances from the retreated position in the direction of extension of the central axis CL, the guide pin 63 moves relatively along the spiral groove 62 as shown by arrow M2. At this time, since the guide pin 63 is fixed to the die 44, it cannot move in the direction of extension of the central axis CL, and actually only rotates in the circumferential direction. As a result, the die 44 rotates around the central axis CL as shown by arrow M3. When the operating member 61 reaches the forward most position on the front side, the die 44 is rotated 25°. Also, when the operating member 61 returns from the forward position to the retreated position, the die 44 rotates 25° in the opposite direction and returns to its original state. The rotational movement of the die 44 can be applied to work applications other than forging work.

Here, the drive unit 8 is different from the main drive source 91, and has a degree of freedom of drive independent of the main drive source 91. Therefore, by variously setting the drive timing and drive speed when the drive unit 8 drives the rotation of the die 44, it is possible to apply the rotation operation of the die 44 to a variety of work applications. In addition, the drive unit 8 using the hydraulic drive source 85 allows for more precise control than, for example, a drive using a kick-out 9F, so that an accurate rotation angle, rotation speed, and appropriate rotation timing of the die 44 can be achieved.

4. Operation example of the forging machine 1 Next, an operation example of the forging machine 1 to which the die rotation device 5 is applied will be described with reference to FIG. 4 and FIG. 5. In the operation example, the forging machine 1 has the first to sixth forging processes (#1 to #6), and the die rotation device 5 is applied to the third forging process (#3). In the operation example, the forging process and the position change process are performed on the workpiece W as shown in FIG. 4. The upper right direction of the paper surface of FIG. 4 corresponds to the upper side of the forging machine 1, and the lower left direction of the paper surface corresponds to the lower side of the forging machine 1. The central axis CL extends in the vertical direction of FIG. 4. In addition, in each forging process (#1, #2, #4, #5, #6) other than the third forging process (#3), the shape of the workpiece W after the forging process is performed is illustrated. In addition, in the second and fourth forging processes (#2, #4), a partial cross section in which a quarter of the workpiece W is cut off is illustrated.

In an example of the operation of the forging machine 1, first, a cylindrical workpiece W is cut by the cutting mechanism. In the next first forging process (#1), the two cut end faces of the workpiece W are corrected and pilot holes H1 are formed in the two end faces. In the next second forging process (#2), bottomed holes H2, which are slightly enlarged versions of pilot holes H1, are formed in the two end faces of the workpiece W. In the next third forging process (#3), instead of forging, a posture change operation is performed to change the posture of the workpiece W (described in detail below).

In the next, fourth forging process (#4), an upsetting process is carried out to change the outer shape of the workpiece W from a cylindrical shape to a rectangular parallelepiped shape. In the next, fifth forging process (#5), a through hole H3 having a roughly rectangular cross section is formed in the workpiece W. In the final, sixth forging process (#6), the internal shape of the through hole H3 in the workpiece W is corrected.

Next, the position change operation of the workpiece W in the third forging process (#3) will be described in detail. FIG. 5 shows a time chart when the position change operation of the workpiece W is performed. The horizontal axis of FIG. 5 is a common time axis t. The three graphs show, from top to bottom, the stroke characteristics of the punch 41, the operating characteristics of the kick-out pin 4A, and the operating characteristics of the operating member 61. FIG. 5 shows one cycle of operation in which the punch 41 moves forward from the rear dead center PR to the front dead center PF and then returns to the rear dead center PR. The operating characteristics of the kick-out pin 4A are realized by the cam shape of the kick-out cam 9F. The operating characteristics of the operating member 61 are realized by the control from the hydraulic fluid control unit 8C and the operation of the fluid path operating unit 8B.

At time t0 in FIG. 5, the punch 41 is at rear dead center PR. At this time, the kick-out pin 4A is at forward position KF. At the same time, the operating member 61 is at retracted position SR, and the die 44 is not rotating. The punch 41 moves forward with a sinusoidal stroke characteristic as time passes after time t0, and reaches front dead center PF at time t2. Meanwhile, the kick-out pin 4A has already returned from the forward position KF to the retracted position KR at time t1, prior to time t2. The operating member 61 maintains the retracted position SR throughout the time the punch 41 is moving forward.

During forward movement, the punch 41 performs a posture change operation to change the inclination posture of the workpiece W relative to the central axis CL instead of a forging operation. Specifically, as shown by arrow A1 in FIG. 4, the punch 41 changes the horizontal posture in which the workpiece W is parallel to the central axis CL to an upright posture in which the workpiece W is perpendicular to the central axis CL. The applicant of the present application has already disclosed an example of the configuration of a forging process that changes the inclination posture of the workpiece W relative to the central axis CL in JP 2018-024007 A. The third forging process (#3) is configured by combining the configuration already disclosed above with the die rotation device 5 of the first embodiment.

The punch 41 then starts moving backward at time t2, and returns to the rear dead center PR at time t9. At time t3, while the punch 41 is moving backward, the kick-out pin 4A starts moving forward from the retracted position KR. Then, at time t4, the operating member 61 starts moving forward from the retracted position SR, and at time t5, the operating member 61 reaches the forward position SF. At time t5, the operations shown by the arrows M1 to M3 in FIG. 3 are completed, and the die 44 is rotated by 25°. As a result, the workpiece W is changed from an upright position to an inclined position inclined by 25°, as shown by the arrow A2 in FIG. 4. In summary, the rotary drive mechanism 6 rotates the die 44 around the central axis CL during the return movement of the punch 41, thereby causing the die 44 to perform a position change operation that changes the rotational position around the central axis CL of the workpiece W.

At time t6, slightly later than time t5, the kick-out pin 4A reaches the forward position KF. As a result, the workpiece W in an inclined position is pushed out to the front of the die 44. The workpiece W in an inclined position is then transported by the work transport section 49 to the next fourth forging process (#4). From the fourth forging process onwards (#4 to #6), the workpiece W is subjected to forging and transport while maintaining its inclined position. After time t6 to time t7, the operating member 61 returns from the forward position SF to the retracted position. After the workpiece W is pushed out, the die 44 rotates 25° in the opposite direction to return to its original state and waits for the next workpiece W to be delivered.

Here, the inclined posture of the workpiece W, which is inclined 25° from the upright posture, is compatible with the shape and operating mode of the finger pairs of the workpiece transport section 49. In other words, the inclined posture of the workpiece W is a posture suitable for the finger pairs to stably grasp and transport. This suppresses problems such as the workpiece W dropping during transport or changing its posture so that it is no longer held by the die 44 in the downstream process. As a result, the operational reliability of the forging machine 1 is improved. In contrast, in a conventional forging machine that does not have a rotation drive mechanism 6, the finger pairs grasp the workpiece W in an upright posture by pinching the sides of the workpiece W, which increases the risk of the workpiece W slipping straight down.

In the die rotation device 5 of the first embodiment, the rotation drive mechanism 6 can rotate the die 44 around the central axis CL, so that the rotational motion of the die 44 can be applied to work applications other than forging. For example, in a forging machine 1 to which the die rotation device 5 is applied, the rotational motion of the die 44 can be applied to the work of changing the position of the workpiece W, thereby preventing the workpiece W from falling.

5. Mold rotation device 5A of the second embodiment
Next, the die rotation device 5A of the second embodiment will be described with reference to Figs. 6 and 7, focusing mainly on the differences from the first embodiment. The die rotation device 5A of the second embodiment can be applied to any of the forging processes of the forging machine 1. However, in the second embodiment, the rotary drive mechanism 6A rotates the punch 41A, which serves as the rotary die, to perform cutting work. This will be described in detail below.

As shown in FIG. 6, the punch 41A has a cutting blade 41K at its tip. The cutting blade 41K is formed in an umbrella shape centered on the central axis CL and has multiple blades extending radially. The rotation drive mechanism 6A is mounted on the ram 3 and has an operating member 61 around the punch 41A. A spiral groove 62 is provided on one of the punch 41A and the operating member 61, and a guide pin 63 is provided on the other of the punch 41A and the operating member 61. The rotation drive mechanism 6A has a configuration similar to that of the first embodiment and rotates the punch 41A around the central axis CL by the same action. On the other hand, the workpiece WA held by the die 44A has a rotationally symmetric shape centered on the central axis CL and has a bottomed round hole WH on the surface facing the punch 41A.

Figure 7 shows a time chart when cutting work is performed on the workpiece WA. The horizontal axis in Figure 7 is a common time axis t. From the top, the three graphs show the stroke characteristics of the punch 41A, the operating characteristics of the kick-out pin 4A, and the operating characteristics of the operating member 61 of the rotation drive mechanism 6A. At time t10 in Figure 7, the punch 41 is at rear dead center PR, the kick-out pin 4A is at forward position KF, and the operating member 61 is at retracted position SR. At time t11, prior to time t12 when the punch 41A reaches front dead center PF, the kick-out pin 4A has already returned from forward position KF to retracted position KR.

At the same time t11, the operating member 61 starts to advance from the retracted position SR, and at time t12, the operating member 61 reaches the advanced position SF. As a result, the punch 41A rotates between time t11 and time t12. Then, before the punch 41A reaches the front dead point PF, the cutting blade 41K abuts against the front inner edge of the circular hole WH in the workpiece WA to perform the cutting operation. As a result, a chamfered portion WM is formed on the front inner edge of the circular hole WH in the workpiece WA.

The punch 41 then starts to move back at time t12, returning to the rear dead center PR at time t19. The kick-out pin 4A moves from the retracted position KR to the forward position KF between time t13 and time t14, and ejects the workpiece WA. Meanwhile, the operating member 61 moves from the forward position SF to the retracted position SR between time t14 and time t15, and the punch 41A rotates in the reverse direction, returning to its original state.

In the second embodiment of the die rotation device 5A, the rotary drive mechanism 6A rotates the punch 41A around the central axis CL during forward movement, causing the punch 41A to perform cutting work instead of heading work. Note that the cutting work performed by the rotating punch 41A is not limited to the chamfering described above. For example, a drill-shaped cutting blade can be provided at the tip of the punch 41A to perform cutting work to drill holes in the workpiece WA.

Furthermore, in a forging machine 1 that uses a die rotation device 5A, forging and cutting operations can be performed in combination. This expands the range of shapes of the workpiece WA that can be manufactured by the forging machine 1.

6. Die Rotation Device 5B of the Third Embodiment
Next, the die rotation device 5B of the third embodiment will be described with reference to Figures 8 and 9, focusing mainly on the differences from the first and second embodiments. The die rotation device 5B of the third embodiment performs a twisting operation on the workpiece WB. In this die rotation device 5B, the punch 41B does not reciprocate along the central axis line CL. Therefore, the die rotation device 5B is not applied to the forging machine 1, and is configured as a standalone device. The die rotation device 5B is configured with a die 44B, a punch 41B, a rotation drive mechanism 6B, and the like.

The die 44B has a central axis CL and is fixed to a frame (not shown). The punch 41B is provided at a position in the extension direction of the central axis CL, rotatably supported by the frame, and positioned opposite the die 44B. As shown in FIG. 8, the die 44B and punch 41B each grip an end of the square bar-shaped workpiece WB. The rotation drive mechanism 6B rotates the punch 41B, which is gripping the workpiece WB, by a predetermined angle around the central axis CL.

As a result, the die 44B and punch 41B work together to perform a twisting operation on the workpiece WB. After the twisting operation is completed, the gripped portion of the workpiece WB is cut off. Finally, the twisted part P shown in FIG. 9 is produced. In the third embodiment, the rotational motion of the punch 41B can be applied to the twisting operation.

7. Modifications and Applications of the Embodiments In the first embodiment, the plate position detector 8D of the drive unit 8 may be omitted, and the position of the operating member 61 may be calculated based on the flow rate of the hydraulic fluid. The drive source 84 of the drive unit 8 is not limited to the hydraulic drive source 85, and may be another type of drive source, such as a motor, that drives the operating member 61. Contrary to the configuration of the first embodiment, a spiral groove 62 may be provided on the outer circumferential surface of the die 44, and a guide pin 63 may be provided on the operating member 61 so as to face inward in the radial direction. It is also possible to use a rotation drive method other than the combination of the spiral groove 62 and the guide pin 63. For example, a configuration may be adopted in which an operating lever extending outward in the radial direction is provided on the rotatably held die 44, and the drive unit rotates the operating lever.

Furthermore, in the third forging step (#3) in FIG. 4, the punch 41 can be configured to move forward to perform the forging operation, and the die 44 can be configured to rotate to perform the position change operation when the punch 41 moves backward. In addition, the use of the rotation of the die 44 is not limited to the position change operation of the workpiece W. For example, when the kick-out pin 4A ejects a workpiece having a helical gear shape, the operating force required for ejection can be reduced by rotating the die 44. In addition, the die 44 may be rotated to change the position of the workpiece W before the punch 41 moves forward to start the forging operation. The present invention is not limited to the configuration of the embodiment, and various applications and modifications other than those described above are possible.

1: Pressing machine 2: Frame 3: Ram 41, 41A, 41B: Punch
44, 44A, 44B: Die 49: Work transport section 4A: Kick-out pin
5, 5A, 5B: Mold rotation device 6, 6A, 6B: Rotation drive mechanism
61: Operating member 62: Spiral groove 63: Guide pin
7: Anti-rotation portion 71: Plane portion 72: Anti-rotation body
8: Drive unit 81: Operation pin 83: Drive pin 842: Connection plate
85: hydraulic drive source 86: cylinder 87: piston 8A: liquid source container
8B: Liquid path operation unit 8C: Working fluid control unit 8D: Plate position detection unit
9: Main drive unit 91: Main drive source
CL: Center axis W, WA, WB: Workpiece WM: Chamfer

Claims (5)

A fixed die having a central axis and holding a workpiece;
a movable die arranged in a direction in which the central axis extends, facing the fixed die, and performing a predetermined operation on the workpiece in cooperation with the fixed die;
a rotation drive mechanism that rotates a rotation die, which is either the fixed die or the movable die, around the central axis line,
The rotation drive mechanism includes:
An operating member that is movable in a direction in which the central axis line extends while sharing the central axis line;
a spiral groove provided in one of the rotary die and the operating member so as to be inclined with respect to the central axis;
a guide pin provided on the other of the rotary die and the operating member and adapted to be engaged with the spiral groove;
a drive unit that drives the operating member in an extension direction of the central axis line to relatively move the guide pin along the spiral groove, thereby rotating the rotary die;
a rotation prevention portion that prevents the operating member from rotating around the central axis,
The rotation prevention portion is
a flat surface portion formed on an outer peripheral surface of the cylindrical operating member disposed on the outer peripheral side of the rotary die, the flat surface portion extending in an extension direction of the central axis line and in a width direction perpendicular to the extension direction;
a rotation prevention body extending in the width direction and contacting the planar portion in the width direction while the operation member moves in the extension direction of the central axis line,
Mold rotation device. The mold rotation device according to claim 1, wherein the rotation drive mechanism has the spiral groove and the guide pin at multiple locations in the circumferential direction. Three or more forging processes, each of which includes a fixed die and a movable die, in which the workpiece is conveyed in sequence;
a main drive source that reciprocates the movable die along a central axis to perform a heading process on the workpiece;
a fixed die having the central axis and holding the workpiece; a movable die arranged in a position in the extension direction of the central axis, facing the fixed die, and performing a predetermined operation on the workpiece in cooperation with the fixed die; and a rotary drive mechanism which rotates a rotary die, which is either the fixed die or the movable die, around the central axis, and a die rotation device which rotates the rotary die at least one of when the movable die moves forward and when it moves backward;
The die rotation device is provided in the forging process in the middle, and performs a posture change operation to change the rotation posture of the workpiece about the central axis instead of the forging process, and transports the workpiece after the posture change to the downstream forging process.
Pressing machine. 4. The pressing machine according to claim 3, wherein the rotation drive mechanism rotates the fixed die about the central axis when the movable die moves back, thereby causing the fixed die to perform a posture change operation that changes the rotational posture of the workpiece about the central axis. 5. The forging machine according to claim 3 or 4, wherein the movable die of the forging process provided with the die rotation device performs a second attitude change operation for changing an inclination attitude of the workpiece relative to the central axis during forward movement , instead of the forging processing operation.

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