JP2000140978A - Die device for fully enclosed forging and fully enclosed forging method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a formed product excellent in quality without any underfill by arbitrarily setting a back pressure to be applied to a counter punch in accordance with a work. SOLUTION: In this die device for fully enclosed forging by which cavities 1a, 2a are enclosed between an upper die 1 and a lower die 2, by pressing/ branching a work 7 in the cavities 1a, 2a with an upper counter punch 8 and a lower counter punch 22, the work 7 in the cavities 1a, 2a is subjected to fully enclosed forging, pressing means 11, 19, in which the cavities 1a, 2a are both side-enclosed by pressing the upper die 1/lower die 2 from up/down directions, are arranged, a back pressure imparting means, in which the work 7 is both side-branched by imparting a back pressure smaller than a forming load to upper/lower counter punches 8, 22 in forming, is arranged above the upper counter punch 8 and below the lower counter punch 22, the back pressure imparted by the back pressure imparting means is arbitrarily set in accordance with the work 7 by a back pressure setting means, by arbitrarily setting corresponding to the work 7, the formed product excellent in quality without any underfill is easily obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a forging die apparatus and a closed forging method used for split flow closed forging.

[0002]

2. Description of the Related Art As a conventional method for manufacturing mechanical parts such as gears by forging, for example, those described in JP-A-5-154598 and JP-A-2534899 are known.

The method of forging a spur gear disclosed in the former publication includes a first processing step of upsetting a primary processing gear having a gear shape smaller than the tooth profile of the gear shape of the spur gear from which a material is to be obtained, and a primary processing gear. A second processing step of compression-molding the secondary processed gear into a secondary processed gear while allowing the material to flow freely in portions other than the tooth profile, and a third processing step of ironing and forming the secondary processed gear into a final product. The process is performed by cold forging, and since the ironing allowance at the time of ironing is formed stably, there is an effect that a highly accurate product can be obtained with a low load.

Further, the extrusion method disclosed in the latter publication is a method in which a projection having a hole is formed by extrusion with a punch having a hole, and a projection-opening end of this portion is pressed at a predetermined pressure. In this method, the pressure is reduced or removed before the processing is completed, and has an effect that the maximum load acting on the mold near the bottom dead center can be greatly reduced.

[0005]

However, in the former forging method, since the material is formed smaller than the gear profile of the gear shape of the spur gear to be obtained in advance, it is difficult to form the material into a gear shape. Since two or more steps are required, and three steps are required for forging a material, the number of steps is large, so that forging takes time and productivity is poor.

[0006] In addition, since the forging is performed by exchanging punches for each process, the exchanging operation becomes complicated, and it is necessary to prepare a plurality of types of punches and mandrels in advance. is there.

On the other hand, in the extrusion processing method disclosed in the latter publication, backward pressing is performed while partially restricting the flow of the material by a pressing member provided on the upper punch, and the pressing force of the pressing member is reduced or reduced before the processing is completed. Since the mold is removed, a high surface pressure acts on the mold from the start of molding, which causes problems such as seizure of the mold and early shortening of the life of the mold. Further, in the extrusion processing method disclosed in the above publication, since the pressing member is provided only on the upper punch side, the pressing force of the upper punch and the lower punch becomes uneven, and the material flows only in one direction. The fiber flow of the obtained product becomes non-uniform, so that the strength of the product is reduced, and defects such as cracks and sink marks are easily generated in the product.

The present invention has been made in order to solve such a problem, and provides a closing forging die apparatus and a closing forging method capable of arbitrarily setting a back pressure in accordance with a work. The object is to make it easy to obtain good quality mechanical parts.

[0009]

In order to achieve the above object, according to the first aspect of the present invention, a cavity is closed between an upper die mounted on a slide side and a lower die mounted on a bolster side. In a closed forging die apparatus for pressurizing and shunting a work in a cavity with an upper counter punch and a lower counter punch provided in an upper die and a lower die to forge the work, the upper die and the lower die are closed. Pressing means is provided below the mold to press the upper mold and the lower mold from above and below to close both sides of the cavity. Also, above the upper counter punch and below the lower counter punch, are formed into upper and lower counter punches during molding. A back pressure applying means for applying a back pressure smaller than the load to divide the work on both sides is provided, and the back pressure applied by the back pressure applying means is arbitrarily set by the back pressure setting means according to the work. Those who wear way.

With the above structure, when the upper die is lowered together with the slide to bring the upper die and the lower die into close contact with each other, the upper die and the lower die are pressed to close both sides of the cavity, and at the same time, the upper counter punch and the lower counter punch are used. Since the work in the cavity can be pressurized from above and below by the back pressure set according to the work and the work can be divided into both sides and flow into the cavity, such as the inner race of gears, bearing races, and constant velocity joints. Even if the corner portion is a molded product having a complicated shape, the material flows to every corner of the corner portion, so that a molded product having good quality without underfill can be easily obtained.

Further, since no burrs are generated on the gear tooth portion and the like, there is no need to remove the burrs after forging, thereby reducing the product cost.

Furthermore, since the hydraulic pressure can be simultaneously supplied to the upper and lower pressurizing means and the upper and lower molds can be closed on both sides, it is possible to supply the pressurized oil with one hydraulic pressure generating device, thereby reducing the equipment cost. In addition, since the hydraulic pressure only needs to be generated during the closed forging, the mold mounting parts and the like can be reduced in size, thereby reducing the price of the mold apparatus.

[0013] In order to achieve the above object, the invention according to claim 2 closes a cavity between an upper die mounted on a slide side and a lower die installed on a bolster side, and forms an upper die and a lower die. In the closing forging die apparatus for press-forging and shunting the work in the cavity by the provided upper counter punch and lower counter punch to close and forge the work, the lower die is pressurized downward from below the lower die. A pressurizing means for closing the cavity on one side is provided, and a back pressure is applied below the upper counter punch and below the lower counter punch to apply a back pressure smaller than the forming load to the upper and lower counter punches at the time of forming to divide the work on both sides. Means is provided, and the back pressure applied by the back pressure applying means can be arbitrarily set by the back pressure setting means according to the work.

With the above construction, the upper mold is lowered together with the slide, and the upper mold and the lower mold are brought into close contact with each other. When the lower mold is pressed, the cavity is closed on one side, and at the same time, the inside of the cavity is closed by the upper counter punch and the lower counter punch. Since the work can be pressurized from above and below by the back pressure set according to the work and the work can be divided into both sides and flow into the cavity, the corner part can be used like a gear, a bearing race, or the inner race of a constant velocity joint. Even if the molded product has a complicated shape, since the material flows to every corner of the corner portion, it is possible to easily obtain a molded product having good quality without underfill.

Since burrs are not generated on the gear tooth portion, the operation of removing the burrs after forging is not required, thereby reducing the product cost.

Further, since the upper and lower dies can be closed by supplying hydraulic pressure to the lower pressurizing means, it is possible to supply pressure oil with one hydraulic pressure generating device, thereby reducing equipment costs. Since the oil pressure needs to be generated only during the closed forging, the size of the mold mounting parts and the like can be reduced, thereby reducing the cost of the mold apparatus.

In order to achieve the above object, the invention according to claim 3 closes a cavity between an upper die mounted on a slide side and a lower die installed on a bolster side, and forms an upper die and a lower die. In a closed forging die apparatus for subjecting a work in a cavity to pressurized shunting by a provided upper counter punch and a lower counter punch, the upper die and the lower die are disposed above the upper die and below the lower die. A pressurizing means for pressurizing the mold from the vertical direction to close both sides of the cavity is provided, and a back pressure for applying a back pressure smaller than the forming load to the upper counter punch during the forming to divide the work to one side above the upper counter punch. A pressure applying means is provided, and the back pressure applied by the back pressure applying means can be arbitrarily set by the back pressure setting means in accordance with a work.

With the above structure, the upper die is lowered together with the slide, and the upper die and the lower die are brought into close contact with each other. Then, the upper die and the lower die are pressed to close both sides of the cavity. Pressure can be applied from above by the back pressure set according to the work, and the work can be diverted to one side and flow into the cavity, so that the corners like the inner race of gears, bearing races, and constant velocity joints Even in the case of a molded article having a complicated shape, the material flows to every corner of the corner portion, so that a molded article having good quality without underfill can be easily obtained.

Further, since no burrs are generated on the gear tooth portion and the like, it is not necessary to remove the burrs after forging, thereby reducing the product cost.

Furthermore, since the hydraulic pressure can be simultaneously supplied to the upper and lower pressurizing means so that the upper and lower molds can be closed on both sides, it is possible to supply the pressurized oil with one hydraulic pressure generator, thereby reducing equipment costs. In addition, since the hydraulic pressure only needs to be generated during the closed forging, the mold mounting parts and the like can be reduced in size, thereby reducing the price of the mold apparatus.

According to a fourth aspect of the present invention, a cavity is closed between an upper mold mounted on a slide side and a lower mold installed on a bolster side. In a closed forging die apparatus for press-dividing the work in the cavity by pressurized shunting of the work in the cavity with the provided upper counter punch and lower counter punch, the upper die is pressurized from above, above the upper die. Pressurizing means for closing the cavity on one side is provided, and above the upper counter punch, back pressure applying means for applying a back pressure smaller than the molding load to the upper counter punch at the time of molding to divide the work to one side is provided. The back pressure applied by the back pressure applying means can be arbitrarily set by the back pressure setting means according to the work.

With the above structure, when the upper mold is lowered together with the slide to bring the upper mold and the lower mold into close contact, the upper mold is pressurized to close the cavity on one side, and at the same time, the work in the cavity is moved by the upper counter punch. Since the work can be divided into one side and flowed into the cavity by applying pressure from above with the back pressure set according to the shape, the corner part has a complicated shape like gears, bearing races, and inner races of constant velocity joints Even in the case of the molded article of the above, since the material flows to every corner of the corner portion, a molded article of good quality without underfill can be easily obtained.

Further, since no burrs are generated on the gear tooth portion and the like, there is no need to remove the burrs after forging, thereby reducing the product cost.

Furthermore, since the upper and lower molds can be closed on one side by supplying hydraulic pressure to the upper pressurizing means, it is possible to supply pressure oil with one hydraulic pressure generating device, thereby reducing equipment costs. At the same time, since it is sufficient to generate the hydraulic pressure only during the closed forging, it is possible to reduce the size of the mold mounting parts and the like, thereby reducing the cost of the mold apparatus.

In order to achieve the above object, the invention according to claim 5 is characterized in that the back pressure setting means includes a variable relief valve, a relief pressure setting means for arbitrarily setting the relief pressure of the variable relief valve, and a back pressure near the slide bottom dead center. It is composed of a logic valve that removes pressure.

With the above configuration, the type and size of the work,
The back pressure can be easily set according to the shape, etc., and by removing the back pressure near the bottom dead center of the slide, no abnormal high pressure is generated in the cavity. In addition, it is possible to solve the problems such as the short life of the mold and the shortened life of the mold.

Since a large forming load is not required, a large work can be formed with a small press.
As a result, equipment can be reduced.

In order to achieve the above object, the invention according to claim 6 is characterized in that a cavity for accommodating a work is closed between an upper mold attached to a slide of a press and a lower mold fixed on a bolster. The work in the cavity is pressurized by the upper counter punch and the lower counter punch to which an arbitrary and smaller back pressure is applied according to the above, and the work is divided.

By the above method, the type and size of the workpiece,
By setting the back pressure arbitrarily according to the shape etc., even if the molded part has a complicated shape such as gears, bearing races, inner races of constant velocity joints, it will reach every corner of the corner Since the material flows, it is possible to easily obtain a molded article having good quality without underfill.

Further, since no burrs are formed on the tooth profile of the gear, it is not necessary to remove the burrs after forging, thereby reducing the product cost.

[0031]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described in detail with reference to the drawings shown in FIGS. FIG. 1 is a cross-sectional view of a closed forging die apparatus for forging mechanical parts (hereinafter referred to as “workpieces”) such as inner races of constant velocity joints, bevel gears, and flange parts by both-side closing and two-side branching, and FIG. FIG. 2 shows a circuit diagram of the device.

In these figures, 1 is an upper mold, 2 is a lower mold,
The upper die 1 is detachably attached to the lower surface of an upper support member 4 via an upper die holder 3, and the upper support member 4 is connected to a slide 6 of a forging press via an upper cylinder block 5.
It is attached to the lower surface. In the center of the lower surface of the upper die 1,
A cavity 1a for molding the work 7 is formed,
Into the cavity 1a, a tapered tip portion 8a of an upper counter punch 8, which is supported at the center of the upper die 1 so as to be slidable up and down, projects so as to be able to protrude and retract from above.

An elevating member 4a for elevating and lowering the upper mold 1 is accommodated in the upper support member 4 so as to be ascendable, and the upper die 1 is attached to a lower surface of the elevating member 4a by a holder 3. A step 4b is formed on the outer peripheral surface of the member 4a, and the step 4b is locked by the locking ring 4c, so that the lifting member 4a does not fall out of the upper support member 4. At the same time, the lower ends of the plurality of operating pins 10 are in contact with the upper surface of the elevating member 4a.

Each of the operating pins 10 is provided so as to vertically pass through an end plate 11a of an outer cylinder 11 provided in the cylinder block 5, and an upper end surface thereof is vertically slidable in the outer cylinder 11. Piston 11 housed in
b is in contact with the lower surface.

Above the piston 11b is a hydraulic chamber 11c.
And the oil passage 5 formed in the cylinder block 5
a and a back pressure generating means 26 of a hydraulic pressure generating device 25 shown in FIG.

At the center of the outer cylinder 11, an inner cylinder 12 is provided.
The lower surface of the piston 12a slidably accommodated in the inside of the piston 12a is in contact with the upper surface of the upper counter punch 8 via the pressing element 13, and is provided in the slide 6 at the center of the piston 12a. A knockout pin 14 of a slide knockout (not shown) is penetrated vertically slidably. The back pressure chamber 12 is located above the piston 12a.
b through the oil passage 5b and the pipe line 29 formed in the cylinder block 5 as shown in FIG.
Connected to 0.

On the other hand, the lower die 2 is mounted via a lower die holder 15 on the upper surface of an elevating member 14a housed in the lower supporting member 14 so as to be able to move up and down. It is mounted on the upper surface of the bolster 17 of the forging press through the intermediary of the forging press. A step 14b is formed on the outer peripheral surface of the elevating member 14a.
The lifting member 14a is prevented from falling out upward by locking the b to the locking ring 14c, and the upper ends of the plurality of operating pins 18 are in contact with the lower surface of the lifting member 14a. .

Each of the operating pins 18 is provided so as to vertically penetrate an end plate 19a of an outer cylinder 19 provided in the cylinder block 16, and a lower end surface thereof is vertically slidable in the outer cylinder 19. Piston 1 housed in
9b is in contact with the upper surface. The lower side of the piston 19b is a hydraulic chamber 19c, and the cylinder block 16
It is connected to a back pressure generating means 26 of a hydraulic pressure generating device 25 via an oil passage 16a formed therein and an electromagnetic valve (not shown).

An inner cylinder 20 is provided at the center of the outer cylinder 19, and the upper surface of a piston 20a housed in the inner cylinder 20 so as to be slidable up and down is
It is in contact with the lower surface of the lower counter punch 22 via the pressing element 21. A tapered tip portion 22a formed at the upper end of the lower counter punch 22 is projected from below into a cavity 2a formed on the upper surface of the lower die 2 so as to be freely protruded and retracted from the lower portion. A knockout pin 23 of a bed knockout (both not shown) provided on the bed is penetrated so as to be vertically slidable.

The lower side of the piston 20a is a back pressure chamber 20b, which is previously filled with oil.
It is connected to a hydraulic pressure generator 25 via an oil passage 16b formed in the cylinder block 16 and a conduit 32 provided with a check valve 31 in the middle. The hydraulic pressure generator 25
Are cylinders 26a and 26 having different diameters as shown in FIG.
b, the hydraulic oil is supplied to the large-diameter cylinder 26a by supplying pressure oil to the small-diameter cylinder 26b from a hydraulic pump (not shown). The back pressure generated by the back pressure generating means 26 is transmitted to the back pressure chamber 1 of the inner cylinder 12 provided on the upper mold 1 side by the back pressure setting means 30 and the pipe line 29.
2b, and are supplied to the back pressure chamber 20b of the inner cylinder 20 provided on the lower mold 2 side by the conduit 32.

The back pressure setting means 30 includes the back pressure generating means 2
Check valve 30a which flows only from 6 to the back pressure chamber 12b side
And a relief pressure setting means 30c for arbitrarily setting the relief pressure of the variable relief valve 30b and the variable relief valve 30b provided in parallel with the check valve 30a. The relief pressure setting means 30c is constituted by, for example, an air-driven hydraulic pump or the like, and
The relief pressure of the relief valve 30b can be set arbitrarily according to the processing conditions such as the type, size, shape, etc.

It is to be noted that a pressure gauge 35 is used for the relief valve 30b so that the relief pressure can be manually set.
The relief pressure may be set while checking the pressure, or a device that can electrically set the relief pressure may be used.

In FIG. 2, reference numeral 33 denotes a back pressure chamber 12 on the upper mold 1 side.
A logic valve for releasing the residual pressure b, which is controlled to be opened and closed by an electromagnetic valve 34 turned on and off by a rotary cam switch (not shown) of the press.

Next, a method for closing and forging the work 7 using the above-configured closing forging die apparatus will be described. When performing the closed forging of the work 7, the split start time and the split direction differ depending on the type, size and shape of the work 7. For this reason, when the closed forging is performed by applying a constant back pressure regardless of the type, size, and shape of the work 7 as in the conventional closed forging die, there is a lack of the work 7 depending on the type, size, and shape. Since meat is generated and a highly accurate molded product cannot be obtained, or burrs are generated, a large number of man-hours are required for deburring work after molding. FIG. 3 shows the relationship between the forming load and the counter punch stroke when performing the closed forging while fixing the counter punch that divides the work 7, and when the slide reaches the vicinity of the bottom dead center, the forming load A sharply increases. Ascending, the material is completely filled in the cavities 1a and 2a at the time point B.

FIG. 4 shows a case where the back pressure applied to the counter punch is removed during the molding, and C ₁
Cavity 1a at the time of -C _3, material in 2a is completely filled, but the faster removal pressure time period, it can be seen that the material becomes longer counter punch stroke until it is fully filled. FIG. 5 shows the relationship between the forming load and the counter punch stroke when the back pressure applied to the counter punch is changed. It can be seen that the higher the back pressure applied, the earlier the forming load increases. And D _{1 to} D ₄
At this point, the material is completely filled in the cavities 1a and 2a. However, even after the material is completely filled, there is no sharp increase in the molding load, so that the mold can be prevented from being damaged. From the above, the back pressure applied to the counter punch is related to the forming load, and by changing the back pressure applied to the counter punch according to the type and size and shape of the work, even if a large forming load is not required. It can be understood that the material can be flowed to every corner of the cavity to obtain a molded product of good quality without underfill.

The present invention focuses on the above points, and arbitrarily sets the back pressure applied to the counter punch in accordance with the type, size, and shape of the work 7 so that a large forming load is not required, and The purpose of the present invention is to obtain a molded product having good quality without meat. In setting the back pressures of the upper and lower counter punches 8 and 22, closed forging of various works 7 is actually performed, and the optimum back pressure is experimentally obtained for each work 7. The relief pressure of the variable relief valve 30b is set by the data.

When the setting of the back pressure smaller than the molding load is completed by the back pressure setting means 30 as described above, with the slide 6 stopped at the top dead center, the lower die 2 is moved by the work transfer means (not shown). After the work 7 is carried into the cavity 2a, the upper die 1 is lowered together with the slide 6,
When the lower surface of the upper mold 1 is brought into close contact with the upper surface of the lower mold 2, back oil is supplied from the back pressure generating means 26 to the outer cylinders 11, 19 in this state.
Are simultaneously supplied to the respective hydraulic chambers 11c and 19c to press the upper mold 1 and the lower mold 2 from above and below, thereby closing the cavities 1a and 2a (this is called both-side closing).

At the same time, the workpieces 7 in the cavities 1a, 2a are vertically moved by the front ends 8a, 22a of the upper counter punch 8 and the lower counter punch 22 projecting into the cavities 1a, 2a by the back pressure in the back pressure chambers 12b, 20b. The work 7 is further pressurized to divide the work 7 into the cavities 1a and 2a (this is referred to as bilateral divergence).
2a, the work 7 is closed and forged, and a pressure corresponding to the work 7 is applied to the upper counter punch 8 and the lower counter punch 22 as a back pressure. The material is filled to every corner of the corner.

The material is filled up to every corner of the cavities 1a and 2a and the internal pressure rises. When the internal pressure rises and the back pressure in the back pressure chamber 12b of the upper mold 1 exceeds the relief pressure of the relief valve 30b. , The relief valve 30b is opened,
The back pressure in the back pressure chamber 12b is returned to the back pressure generating means 26 side, and when the slide 6 reaches the vicinity of the bottom dead center, the solenoid valve 34 is turned on by a signal from a rotary switch of the press, and the solenoid valve 34 is turned on. Since the lodge valve 33 is opened by the supplied pressure oil, the back pressure chamber 12b communicates with the back pressure generating means 26, and the back pressure in the back pressure chamber 12b is reduced to the pressure generated by the back pressure generating means 26. Depressurized. As a result, the molding load does not abnormally increase near the bottom dead center of the press, so that damage to the mold can be prevented.

When the molding of the work 7 is completed as described above, as the slide 6 starts to move up together with the upper mold 1, the knock pin 14 is firstly knocked out by the slide knockout.
Is pushed down, the work 7 attached to the upper mold 1 is knocked out, and then, as the slide 6 further rises, the knockout pin 23 is pushed up by the bed knockout, and the work 7 is knocked out from the lower mold 2. The work 7 having been formed is carried out by the work transfer device.

By repeating the above operation, the work 7 is closed and forged. The upper and lower dies 1 and 2 are closed on both sides, and at the same time, the work 7 is inserted into the upper and lower counter punches 14 and 22.
Forging is performed by diverting the work 7 on both sides while applying the optimum back pressure according to the type, size, shape, etc. of the product, so that a good molded product with no underfill at every corner of the corner can be obtained. become.

In the first embodiment, the upper and lower dies 1
6 and the upper and lower counter punches 8 and 22 are simultaneously pressed in the vertical direction. FIG. 6 shows an embodiment in which one side is closed and both sides are divided, and FIG. 7 shows an embodiment in which both sides are closed and one side is divided. FIG. 8 shows an embodiment in the case of one-side occlusion, and FIG. 8 shows an embodiment in the case of one-side branch flow.

Next, these embodiments will be described. The same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. In the second embodiment shown in FIG. 6, only the lower mold 2 is pressurized from below by the piston 19a of the outer cylinder 19 and closed on one side.
The back pressure is applied to the workpiece 22 from above and below to divide the work 7 on both sides. The cavities 1a and 2a are filled with the works 7 branched on both sides, and the internal pressure exceeds a preset relief pressure. When this occurs, the relief valve 30b is opened to relieve the back pressure in the back pressure chamber 12b.

In the third embodiment shown in FIG. 7, the upper die 1 and the lower die 2 are
b and 19b to simultaneously pressurize and close both sides, and simultaneously apply a back pressure only from above to the upper counter punch 8 to divide the work 7 into one side.
When the work 7 that has been diverted to one side is filled in a and 2a and the internal pressure exceeds a preset relief pressure, the relief valve 30b is opened to relieve the back pressure in the back pressure chamber 12b. Things.

Further, in the fourth embodiment shown in FIG. 8, only the upper die 1 is pressurized by the piston 11b of the outer cylinder 11 to close one side, and at the same time, a back pressure is applied only to the upper counter punch 8 from above. The work 7 is diverted to one side, and when the cavities 1a and 2a are filled with the work 7 diverted to one side and the internal pressure exceeds a preset relief pressure, the relief valve 30b is opened and the back is opened. Pressure chamber 12b
It is designed to relieve the back pressure inside. Even in the case of any of the above embodiments, a molded product of good quality without underfill can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view of a closed forging die apparatus according to a first embodiment of the present invention.

FIG. 2 is a circuit diagram of a hydraulic pressure generator used in the closed forging die apparatus according to the first embodiment of the present invention.

FIG. 3 is a diagram showing the relationship between the forming load and the stroke of the counter punch when the closed forging is performed by fixing the counter punch of the closed forging die apparatus.

FIG. 4 is a diagram showing the relationship between the forming load and the stroke of the counter punch when the closed punch forging is performed by removing the back pressure of the counter punch of the closed forging die apparatus during the forming.

FIG. 5 is a diagram showing the relationship between the forming load and the stroke of the counter punch when the counter punch of the die apparatus for closed forging is always subjected to closed forging by applying a back pressure.

FIG. 6 is a sectional view of a closed forging die apparatus according to a second embodiment of the present invention.

FIG. 7 is a sectional view of a closed forging die apparatus according to a third embodiment of the present invention.

FIG. 8 is a sectional view of a closed forging die apparatus according to a fourth embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Upper mold 1a ... Cavity 2 ... Lower mold 2a ... Cavity 6 ... Slide 7 ... Work 8 ... Upper counter punch 11 ... Pressurizing means (outer cylinder) 12 ... Back pressure applying means (inner cylinder) 17 ... Bolster 19 ... Addition Pressure means (outer cylinder) 20 ... Back pressure applying means (inner cylinder) 22 ... Lower counter punch 30 ... Back pressure setting means 30b ... Variable relief valve 30c ... Relief pressure setting means 33 ... Logic valve

 ──────────────────────────────────────────────────続 き Continued on front page F term (reference) 4E087 AA02 AA04 AA06 AA10 CA14 CA22 CA33 CB03 DA04 DA05 EB03 EC01 EC12 EC18 EC38 EC46 EC50 EC57 ED22 EE02 HA01 HA21 HA23 HA25 HB01

Claims (6)

[Claims] 1. An upper die (1) mounted on a slide (6) side and a lower die (2) mounted on a bolster (17) side.
, The cavities (1a) and (2a) are closed, and the upper counter punch (8) and the lower counter punch (22) provided in the upper die (1) and the lower die (2) close the cavity (1).
a) In a closing forging die apparatus for closing and forging a work (7) by pressurizing and shunting a work (7) in (2a), an upper part of the upper die (1) and a lower part of a lower die (2). The pressurizing means (1) presses the upper mold (1) and the lower mold (2) from above and below to close both sides of the cavities (1a) and (2a).
1) and (19), and above the upper counter punch (8) and below the lower counter punch (22),
Back pressure applying means (12) and (20) for applying a back pressure smaller than the forming load to the upper and lower counter punches (8) and (22) to divide the work (7) on both sides are provided. The back pressure applied by the means (12) and (20) is
A closed forging die apparatus which can be arbitrarily set by a back pressure setting means (30) according to a work (7). 2. An upper mold (1) mounted on the slide (6) side and a lower mold (2) installed on the bolster (17) side.
, The cavities (1a) and (2a) are closed, and the upper counter punch (8) and the lower counter punch (22) provided in the upper die (1) and the lower die (2) close the cavity (1).
a) In a closing forging die apparatus for subjecting a work (7) in (2a) to pressurized shunting and closing and forging the work (7), a lower die (2) is placed below the lower die (2). A pressurizing means (19) is provided for closing the cavities (1a) and (2a) on one side by applying pressure from below, and is formed above the upper counter punch (8) and below the lower counter punch (22) during molding. Back pressure applying means (12) and (20) for applying a back pressure smaller than the forming load to the upper and lower counter punches (8) and (22) to divide the work (7) on both sides are provided. (12) The die apparatus for closed forging, wherein the back pressure applied by (20) can be arbitrarily set by the back pressure setting means (30) according to the work (7). 3. An upper mold (1) mounted on the slide (6) side and a lower mold (2) installed on the bolster (17) side.
, The cavities (1a) and (2a) are closed, and the upper counter punch (8) and the lower counter punch (22) provided in the upper die (1) and the lower die (2) close the cavity (1).
a) In a closing forging die apparatus for closing and forging a work (7) by pressurizing and shunting a work (7) in (2a), an upper part of the upper die (1) and a lower part of a lower die (2). The pressurizing means (1) presses the upper mold (1) and the lower mold (2) from above and below to close both sides of the cavities (1a) and (2a).
1) and (19), and a back pressure that applies a back pressure smaller than the forming load to the upper counter punch (8) during the forming to divide the work (7) to one side above the upper counter punch (8). In addition to providing the applying means (12), the back pressure applied by the back pressure applying means (12) can be arbitrarily set by the back pressure setting means (30) according to the work (7). Forging die equipment. 4. An upper die (1) mounted on the slide (6) side and a lower die (2) mounted on the bolster (17) side.
, The cavities (1a) and (2a) are closed, and the upper counter punch (8) and the lower counter punch (22) provided in the upper die (1) and the lower die (2) close the cavity (1).
a) In a closed forging die apparatus for closing and forging the work (7) by pressurizing and shunting the work (7) in (2a), the upper die (1) is placed above the upper die (1). A pressurizing means (11) is provided for closing the cavities (1a) and (2a) on one side by applying pressure from above, and a molding load is applied to the upper counter punch (8) during molding above the upper counter punch (8). A back pressure applying means (12) for applying a smaller back pressure to divide the work (7) into one side is provided, and the back pressure applied by the back pressure applying means (12) is adjusted according to the work (7). A die apparatus for closed forging, characterized in that it can be arbitrarily set by a pressure setting means (30). 5. A variable relief valve (30b) for a back pressure setting means (30), a relief pressure setting means (30c) for arbitrarily setting a relief pressure of the variable relief valve (30b), and a slide (6) bottom dead center. The die apparatus for closed forging according to any one of claims 1 to 4, further comprising a logic valve (33) for reducing back pressure in the vicinity. 6. A cavity (1) containing a work (7) between an upper die (1) attached to a slide (6) of a press and a lower die (2) fixed on a bolster (17).
a) and (2a) are closed by closing the upper and lower counter punches (8) and (22) with the back pressure arbitrarily and smaller than the forming load applied according to the work (7). A closed forging method characterized in that the work (7) is pressurized to divide the work (7).