JP2001047173A - Die forging method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a die forging method having the advantage, such as high productivity, and high forming precision. SOLUTION: The die forging method is executed by forming a fitting part 4, flange part and a fitting part 6 with a step part in a spout tip metal 3 with an upper outer punch 20 and an upper die 19 in a pre-forging process. In a hole-forming process thereafter, while retreating a die pin 13 under loading the back pressure in the one end surface of a forging blank, a recessing and projecting part 7 is formed by punching an inner punch into the forging blank. Since a part of the forging blank is filled in a die cavity in the forging process, the shape of the formed part in the forging process can precisely be created.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a die forging method.

[0002]

2. Description of the Related Art Japanese Patent Application Laid-Open No. 55-15663 discloses
An inner punch and an outer punch (hollow die spin) are provided on the lower and upper dies for forging the metal molded product, respectively, so that they can be driven independently. After forming with the upper and lower dies and the upper and lower outer punches, There is disclosed a molding technique for improving the quality of a product by improving the flow of material by molding with an inner punch.

Japanese Patent Application Laid-Open No. 58-84632 discloses a closed die forging method using a superplastic metal. In this forging method, when a molding force reaches a certain value during forging, the mold is forged. There is a description that the movement of a movable portion provided in a part forms a filling gap inside the mold, allows excess metal to flow into the gap, and removes the surplus portion later to improve dimensional accuracy.

Japanese Patent Application Laid-Open No. 1-228638 discloses a forging method in which a part of a forging material is laterally extended in a pre-forging step, and an extended portion is formed in a post-forging step. In this method, both steps use separate molds.

[0005] Japanese Patent Application Laid-Open No. 2-274341 discloses a forging method in which a forged material is extended laterally and a gear is formed at the tip of the extended portion.

[0006] Japanese Patent Application Laid-Open No. 4-17934 discloses a forging method in which a punch is punched into a forged material to form a deep hole while backing the die spin by applying back pressure.

Japanese Patent Application Laid-Open No. 4-344845 discloses a method of forging while gradually increasing the back pressure.

Japanese Patent Application Laid-Open No. 7-236937 discloses that a forged material is firstly compressed by upper and lower dies to form an overhanging portion, and a punch is driven into the forging material to further overhang the overhanging portion. A method of forming a gear at the tip of the part is disclosed.

Outline of the 89th Autumn Meeting of the Japan Institute of Light Metals (1
995) p. Nos. 109 and 110 disclose a method of forging a scroll for a compressor (a spiral blade) while applying a back pressure.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to provide a die forging method having features such as high productivity and high molding accuracy.

[0011]

Means for Solving the Problems and Functions / Effects In order to solve the above problems, a die forging method according to one aspect of the present invention includes:
A forging method in which a forged material is plastically flowed by being pressed in a forging mold to form a predetermined shape; a pre-forging step and a subsequent hole forming step are performed using the same mold;
In the pre-forging step, at least a part of the forging material is forged so as to fill the cavity of the mold to obtain a part of the shape of the molded product. A hole is formed by driving a punch into the forged material while retreating while applying back pressure. Note that, in the present invention, "retracting in a state in which a back pressure is applied" means that in the case where the mold pressure is greater than the back pressure, it is a preferable embodiment to retreat naturally according to the differential pressure.

In the mold forging method disclosed in Japanese Patent Application Laid-Open No. 55-156631, the die spin is retracted before the forging material is filled in the mold cavity in the pre-forging step. On the other hand, in the die forging method of this aspect of the present invention, since a part of the forging material is filled in the die cavity in the forging step (closed forging), it is possible to accurately create the shape of the pre-forging step forming part. it can.

According to another aspect of the present invention, there is provided a die forging method comprising: performing a pre-forging step and a subsequent hole forming step using the same die;
In the pre-forging step, a part of the shape of the molded product is obtained,
In the hole forming step, a punch is punched into the forged material to form a hole while the die spin is applied to one end surface of the forged material and retreated under a back pressure, and the die spin is not moved during the pre-forging. It is characterized by the following.

In the die forging method disclosed in Japanese Patent Application Laid-Open No. 55-156631, the die spin is moved in the pre-forging step. on the other hand,
In the die forging method according to this aspect of the present invention, since the die spin is not moved until the outer shape of the molded product is completed, forging can be stably performed and the shape of the pre-forging step molded portion can be accurately created. .

According to another aspect of the present invention, there is provided a die forging method comprising: performing a hole forming step and a subsequent forging step using the same die;
In the hole forming step, while punching a punch into the forged material to form a hole while retracting while applying back pressure by applying a die spin to one end surface of the forged material,
In the post-forging step, at least a part of the forging material is forged to obtain a shape of a part of a molded product.

Japanese Patent Application Laid-Open No. 55-156631,
No. 344,845 does not have a separate forging step after the hole forming step. On the other hand, according to the die forging method of this aspect of the present invention, complicated and diverse molding can be performed in the post-forging step.

According to another aspect of the present invention, there is provided a die forging method in which a hole forming step and a forging step before or after the hole forming step are performed using the same die, and in the hole forming step, a die spin is applied to one end surface of the forged material. While retracting while applying back pressure, a punch is punched into the forged material to form a hole, and in the forging process, the die spin is basically prevented from retreating against the molding pressure of the forged material. It is characterized by holding.

In Japanese Patent Application Laid-Open No. 55-156631, the pressing force of the punch for pressure molding is changed depending on the process. However, in this embodiment of the present invention, a die spin dedicated to back pressure that is not pushed into a forged material is used. Changing holding power.

According to another aspect of the present invention, there is provided a die forging method comprising: a step of punching a punch into the forging material to form a hole while retracting the die-spin against one end surface of the forging material under a back pressure; The method includes a forming step, wherein the punch is driven from a direction other than the retreat direction of the die spin or the reverse direction.

Japanese Patent Application Laid-Open No. 55-156631 discloses that the punching direction is opposite to the retreating direction of the die spin.
-344845 is limited to the same direction. According to the die forging method of this aspect of the present invention, since punches are punched in a direction other than the retreat direction of the die spin or the reverse direction, products having complicated and various shapes such as cheese can be formed.

According to another aspect of the present invention, there is provided a mold forging method comprising: combining a mold for forging the outer shape of a molded product with a punch for forming a concave portion of the molded product; During the forging, the die spin is retracted while applying back pressure to the die spin.

The mold described in Japanese Patent Application Laid-Open No. 55-156631 (reference numeral 2 'in FIG. 10 of the same publication) does not forge while pushing the mold. According to the die forging method of this aspect of the present invention, a product having a complicated shape such as an impeller can be formed.

According to another aspect of the present invention, there is provided a die forging method in which a plurality of punches forming a plurality of recesses are pressed against a forging material from the same direction to perform forging, and a back pressure is applied to the die spin during forging. It is characterized by being retracted while moving.

In Japanese Unexamined Patent Publication (Kokai) No. 55-156631, the number of the concave forming punches is one each for upper and lower parts. On the other hand, according to this aspect of the present invention, forging is performed by pressing a punch that forms a plurality of concave portions against the forging material from the same direction, so that products having complicated and various shapes such as deep holes with steps can be obtained. Can be molded.

In the die forging method of this aspect, the molding may be performed by using the die and the punch at different timings. Alternatively, molding may be performed using a plurality of punches at different timings. When the mold and punch (or multiple punches) are operated together,
At the time of forging, there may be a problem that the meat near the root of the punch becomes missing. However, if molding is performed using both at different timings, such a problem can be prevented.

A die forging method according to another aspect of the present invention is characterized in that a plurality of punches are simultaneously punched into a forging material from different directions to perform molding, and during forging, the die spin is retracted while applying back pressure. And

According to the die forging method of this aspect of the present invention,
It is possible to obtain forged products of complicated and various shapes such as cheese.

According to another aspect of the present invention, there is provided a die forging method in which a punch is pressed or a die is pressed into the forged material while the die spin is applied to one end surface of the forged material and retreated under a back pressure. The method includes a forging step, wherein a plurality of the die spins are provided to form a plurality of holes.

According to the die forging method of this aspect of the present invention,
A product having a complicated shape having a large number of holes such as a multi-header can be formed.

In the die forging method of this aspect, it is preferable that the plurality of die spins are sequentially operated with a time lag to sequentially form the plurality of holes. In this case, since the flow of the material is simpler than in the case where the die spin is simultaneously operated to form a plurality of holes at the same time, defects such as entrapment and underfill can be reduced.

According to another aspect of the present invention, there is provided a die forging method comprising: pressing a punch or a die against the forged material in a state where a die spin is applied to one end surface of the forged material to apply pressure; In this process, the die spin is not retracted when the internal pressure of the mold is equal to or less than a predetermined pressure, and the die spin is retracted when the internal pressure of the mold exceeds the predetermined pressure.

Japanese Unexamined Patent Publication (Kokai) No. 55-156632 and Japanese Unexamined Patent Publication (KOKAI)
344845 and JP-A-4-17934 have no idea that excess forged material is released. JP-A-58-84
No. 632 describes a closed die forging method using a superplastic metal. In this forging method, a movable part provided in a part of a mold is provided when a forming force reaches a certain value during forging. Describes that a gap is formed inside the mold by the movement of, a surplus metal is caused to flow into the gap, and the dimensional accuracy is improved by removing the surplus portion later.
However, in this method, when the surplus portion flows into the filling gap portion, the inside of the mold is not in a closed state (filled state). In the die forging method according to this aspect of the present invention, the die spin is retracted according to the pressure of the material in the die, that is, the die spin is retracted while maintaining the closed state.

According to another aspect of the present invention, there is provided a die forging method comprising: a step of punching a punch into the forging material to form a hole while applying a die spin to one end surface of the forging material so as to retreat under a back pressure; The method includes a forming step, in which an uneven portion is provided on an end surface for applying the back pressure of the die spin, and a part of the product shape is formed by the uneven portion.

In Japanese Patent Application Laid-Open No. 55-156631 and two other cases,
The end face that gives the back pressure of the die spin is a flat surface without irregularities. According to the die forging method of this aspect of the present invention, a convex portion or a concave portion can be formed on a forming surface, and a forged product having a complicated and various shape can be obtained.

A die forging method according to another aspect of the present invention includes: an overhanging step of forming an overhang by forging; and a forming step of further forging the overhang and forming the overhang into a predetermined shape. It is characterized in that it is performed in the same mold.

In Japanese Patent Application Laid-Open No. 1-228638, the overhanging step and the forming step are performed by different molds. JP-A-2-2743
No. 41 and Japanese Patent Application Laid-Open No. 7-236937 do not hit a punch or a mold against the overhang portion, but form only the overhang portion. Compared with these prior arts, in this aspect of the present invention, the overhanging portion overhanging in the overhanging step is forged with a punch or the like in the forming step, so that the filling property of the material is better than that of forming only by overhanging. Also,
Since the overhanging step and the forming step are performed in the same mold, the number of types of the mold can be reduced, and the cost of the mold can be reduced. Furthermore, since it is not necessary to transfer a forged material to another press during forging, productivity is high.

A die forging method according to another aspect of the present invention includes: an overhanging step of forming an overhang by forging; and a forming step of further forging the overhang and forming the overhang into a predetermined shape. The overhanging portion extends in the same direction as the forging or in the opposite direction.

In Japanese Unexamined Patent Publication No. 1-228638, the overhanging portion extends laterally in the forging direction. In the die forging method according to this aspect of the present invention, “in the same direction or in the opposite direction to forging” refers to protruding a part of the forging material in the same direction as the movement of the die or pin during forging or in the opposite direction. According to this die forging method, complicated and various forged products can be obtained.

A die forging method according to another aspect of the present invention includes: an overhanging step of forming an overhang by forging; and a forming step of further forging the overhang and forming the overhang into a predetermined shape. The forging material is forged a plurality of times.

In Japanese Patent Laid-Open No. 1-28638, the upper and lower punches are simultaneously pushed to overhang. In the die forging method according to this aspect of the present invention, the forging material is forged a plurality of times in the overhanging process, whereby the overhanging portion is formed more smoothly than when all the overhanging portions are formed by a single forging. Burrs are less likely to occur on the overhang.

According to another aspect of the present invention, there is provided a die forging method comprising: simultaneously driving a first punch into a forged material; and forging the forged material by a second punch or die without retreating the first punch. It is characterized by processing.

According to the die forging method of this aspect of the present invention,
There is an advantage that the part formed by the first punch does not collapse.

According to another aspect of the present invention, there is provided a die forging method wherein a first punch is punched into a forged material to form a hole, and after the completion of the hole forming, the periphery of the hole is removed by a second punch or die without removing the punch. It is characterized by forging.

In Japanese Patent Application Laid-Open No. 55-156631, forging around a hole is performed before completion of hole forming. According to the die forging method of this aspect of the present invention, the periphery of the hole is forged by the second punch or die without removing the punch after completion of the hole forming.

According to another aspect of the present invention, there is provided a die forging method in which a forging material is plastically flowed by being pressed in a forging die to form a predetermined shape; A first step of defining a cavity in the direction, and pressing the forging material from the other end side of the forging material, thereby projecting the one end of the forging material to fill the cavity and fill the cavity. And a third step of forming a recess in the overhang by axially punching a punch from the end face of the one end into the overhang after the second step. And a step of:

By continuously forming the overhang portion and the concave portion on the forged material, the material yield, productivity, and molding accuracy can be increased, and forging defects can be suppressed. Further, the outer shape of the overhang portion can be accurately formed. After forming the first concave portion, a second concave portion having a diameter larger than the first concave portion and shallower than the first concave portion is continuously formed in the overhang portion by using the second punch arranged on the outer peripheral portion of the punch. You may.
In this case, flow inhibition of the material that occurs when the first concave portion and the second concave portion are simultaneously formed does not occur, and it is possible to prevent the overhanging portion from being cut off. Furthermore, if a notch is provided in a part of the die spin, a protrusion can be formed on a part of the end face of the forged material at the same time as the formation of the overhang.

A die forging method according to another aspect of the present invention is a die forging method in which a forging material is plastically flowed by being pressed in a forging die to form a predetermined shape; A step of punching a punch in the forging material in the axial direction from the end face to form a concave portion, and thereafter,
Using a second punch arranged on the outer periphery of the punch,
The method further comprises a step B of forming a second concave portion having a diameter larger than that of the concave portion and shallower than the concave portion.
The method is characterized in that the method includes retreating a die spin in contact with the other end of the forged material while applying back pressure.

There is no flow-back in which the concave volume of the forged material is pushed up in the direction opposite to the punch, and the forged material flows continuously and smoothly, so that micro cracks do not occur in the product. Further, since the pressing force of the punch may be substantially equal to the material processing force, the depth of the concave portion can be freely set without buckling of the punch.

According to another aspect of the present invention, there is provided a mold forging method comprising: forging a forged material into a forging material to form a plastic flow by pressurizing the forged material; A first step of projecting an original part of the projection on the top of the forged material; and after the first step, crushing the original part in a direction opposite to the direction in which the original part is extended. And a second step of projecting the convex portion to the side.

By continuously molding the cylindrical portion and the convex portion having the undercut, the material yield, productivity and molding accuracy are increased, and the crack in the cylindrical portion and the entrapment of the surface layer in the undercut portion are prevented. As a result, forging defects are less likely to occur.

A die forging method according to another aspect of the present invention is a die forging method in which a forged material is plastically flowed by being pressed in a forging die to form a molded product having a top-end cylindrical shape:
A step of pressing the punch into the center of the forged material and extruding backward while applying a back pressure to the end of the cylindrical portion while forming the outer peripheral surface of the cylindrical portion with the die cavity surface;
A step B of first punching out the punch used to form the cylindrical part when removing the molded part; and a die formed from the die used to form the outer peripheral surface of the cylindrical part after the step B. C step of extracting

By reducing the pulling force of the punch or die, deformation of the molded product can be prevented, and the molded product can be reliably taken out.

[0053]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a view schematically showing a structure of a brass flush fitting formed by a die forging method according to one embodiment of the present invention, FIG. 1 (A) is a plan view, and FIG. 1 (B) is a side sectional view. FIG. 1 (C) is a perspective view. The faucet fittings installed in kitchens and bathrooms are provided with parts called spouts.
A spout tip fitting 3 made of brass is mounted inside the vicinity of the tip of the spout.

The upper end of the brass spout tip fitting 3 of this example is a substantially D-shaped fitting part 4. A guide inclined surface 4 a is formed on an edge of the fitting portion 4. Further, the spout tip fitting 3 includes a flange portion 5 having a slightly larger diameter than the fitting portion 4, a stepped fitting portion 6, and an uneven portion 7 extending downward from the stepped fitting portion 6. It is formed integrally. The concavo-convex portion 7 is a relatively small-diameter bottomed cylinder having a convex portion 7b having a circular cross section and a concave portion 7 inside the convex portion 7b. The convex portion 7b is formed on the extension of the concave portion forming direction at the same time as the concave portion 7a is formed.

As will be described later, portions other than the uneven portion 7 are
Completed by forming the brass material in a state where the volume of the molding cavity is almost equal to the volume of the brass material (the forged material fills the cavity) in the first half of the molding after the mold clamping (pre-forging process) Formed into a state. The uneven portion 7 is continuously formed in a subsequent deep hole forming step.

The spout tip fitting 3 has a plurality of sharp edges 6a. In the pre-forging step, the plurality of sharp edges 6a are also formed with high precision.

Next, preferable materials of the brass material will be described. In order to reduce the deformation resistance during forging,
The brass material preferably has the following crystal structure. (A) a crystal structure having an average particle diameter of 15 μm or less; (b) an apparent Zn content of 37 to 50 wt%;
Content is 0.5 to 7 wt%, preferably 1.7 to 2.2.
wt%, and (c) the ratio of α phase at 450 ° C. is 4
It has a crystal structure of 4 to 65%, the ratio of β phase is 10 to 55%, and the ratio of γ phase is 1 to 25%.

FIGS. 2 to 4 are cross-sectional views schematically showing an apparatus for forging the spout tip metal fitting of FIG. 1 and a forging step. The brass material forging device 10 includes a main body frame (not shown), a lower mold 11, and an upper mold 17 corresponding to the lower mold 11.
And The lower die 11 includes a lower die 12, a die spin 13, and a first hydraulic cylinder 14 that holds the die spin 13 and is capable of driving up and down. The lower die 12 is fixed, and the upper surface of the lower die 12 is horizontal. At the center of the lower die 12, a pin insertion hole 15 having a vertical circular cross section is provided. The die pin 13 is slidably mounted in the pin insertion hole 15 up and down. The outer shape of the uneven portion 7 of the spout tip metal fitting 3 is formed by the pin insertion hole 15 and the die pin 13.

Near the pin insertion hole 15 on the upper surface of the lower die 12, a stepped hole 16 (see also FIG. 6) is formed so as to communicate with the upper end of the pin insertion hole 15. The stepped forming hole 16 is for forming the stepped fitting portion 6 of the spout tip fitting 3. The first hydraulic cylinder 14 is disposed vertically below the die pin 13, and the upper end of the piston rod 14 a of the first hydraulic cylinder 14 is
3 is connected. The first hydraulic cylinder 14 holds the die pin 13 at the position shown in FIGS.
The die spin 13 can be lowered while applying a holding force. Furthermore, the die pin 13 can be raised by the cylinder 14 to eject the spout tip metal fitting 3 after molding.

The upper die 17 has an upper slide 18 and an upper die 19. The upper die 17 is provided with an upper outer punch 20.
And an upper inner punch 21. Upper slide 18
Is moved up and down by the main hydraulic cylinder 22.
The upper inner punch 21 is moved up and down by a third hydraulic cylinder 23. The upper slide 18 is vertically vertically slidably guided via a guided portion slidably engaged with a guide portion formed on the main body frame, and is driven up and down by a main hydraulic cylinder 22. A recess 24 having a circular cross section is formed at the center of the lower portion of the upper slide 18 so as to open toward the lower surface. At least the upper end of the upper die 19 is mounted in the recess 24 so as to be slidable up and down. A flange 19a is formed at the upper end of the upper die 19, and the flange 19a is provided on the locking plate 2 fixed to the lower surface of the upper slide 18.
5 locked.

The lower surface of the upper die 19 is formed in a horizontal plane in contact with the upper surface of the lower die 12. A plurality of spring receiving holes 26 are formed in an upper part of the upper die 19 so that an upper end is open. A compression spring 27 is mounted in each of the spring receiving holes 26. The upper ends of these compression springs 27 are received by the upper end wall surface of the concave portion 24, and the upper die 1
9 is strongly elastically urged downward by these compression springs 27. A punch insertion hole 28 having a substantially D-shaped cross section, into which the upper outer punch 20 and the upper inner punch 21 can be inserted, is formed in the center of the upper die 19 in a vertical direction. The upper outer punch 20 and the upper inner punch 21 are slidably inserted into the punch insertion holes 28.

On the lower surface of the upper die 19, a flange forming portion 29 (see also FIG. 6) located outside the punch insertion hole 28 is provided. The flange forming portion 29 is for forming the flange portion 5 of the spout tip metal fitting 3. 2, the flange forming portion 29 of the upper die 19 communicates with the step forming portion 16 of the lower die 12. The upper outer punch 20 is formed integrally with the upper slide 18 and slidably inserted into the punch insertion hole 28. The outer shape of the cross section of the upper outer punch 20 is substantially D-shaped. At a lower end portion of the upper outer punch 20, a fitting portion forming portion 30 (see also FIG. 6) for forming the fitting portion 4 of the spout tip metal fitting 3 is formed. As shown in FIG. 2, in the clamped state, the fitting portion forming portion 30 is in spatial communication with the stepped forming portion 16.

The upper inner punch 21 is mainly used for forming the uneven portion 7 of the spout tip metal fitting 3, and is formed in a circular cross section. The upper inner punch 21 is provided with the inner punch insertion hole 3 at the center of the upper outer punch 20.
1 is inserted to be able to move up and down. Upper inner punch 21
Is connected to a piston rod 23a of a third hydraulic cylinder 23 disposed thereabove, and is driven up and down by the cylinder 23. In FIG. 2, a short cylindrical brass material 3A is set in a mold. The brass material 3A is formed into the spout tip metal fitting 3 shown in FIG. 4 through the intermediate formed body 3B shown in FIG.

Next, the hydraulic control system of the brass forging device shown in FIGS. 2, 3 and 4 will be described. FIG. 5 is a diagram schematically showing a configuration of a hydraulic control system of the brass material forging device shown in FIGS. This hydraulic control system has a hydraulic supply device 41 that supplies hydraulic pressure to the first hydraulic cylinder 14, the second hydraulic cylinder 22, and the third hydraulic cylinder 23. In addition, a hydraulic circuit including electromagnetic directional switching valves 42 to 44 and electromagnetic proportional relief valves 45 and 46 is provided. Further, it has a plurality of detection switches 47 and a control unit 48. The hydraulic pressure supply device 41 has a hydraulic pump, a drive motor, an oil tank, and the like (not shown).

The electromagnetic directional change valve 42 is installed in an oil passage for supplying oil pressure to the second hydraulic cylinder 22, and the electromagnetic directional cut valve 43 is installed in an oil passage for supplying oil pressure to the first hydraulic cylinder 14. , The electromagnetic directional control valve 44 is connected to the third hydraulic cylinder 2.
3 is installed in an oil passage that supplies hydraulic pressure.

The electromagnetic proportional relief valve 45 is connected to an oil passage for supplying hydraulic pressure to the first hydraulic cylinder 14, and the hydraulic pressure set by the electromagnetic proportional relief valve 45 is supplied to the cylinder 14. By setting the electromagnetic proportional relief valve 45, the back pressure of the die pin 13 is set. Similarly, the electromagnetic proportional relief valve 46 is connected to the third hydraulic cylinder 23
The cylinder 23 is supplied with a hydraulic pressure set by an electromagnetic proportional relief valve 46.

The plurality of detection switches 47 are connected to the upper die 19.
And a detection switch for detecting the upper and lower limit positions of the upper inner punch 21.

The control unit 48 has a microcomputer and an input / output interface. Based on detection signals from the plurality of detection switches 47, the ROM of the microcomputer stores the hydraulic pressure supply device 41, the electromagnetic directional change valves 42 to 44, and the electromagnetic proportional relief valves 45 and 46.
A control program for controlling is stored. The microcomputer performs a control operation according to the control program.

Next, a method of forging and forming the spout tip 3 using the above-described forging apparatus 10 will be described in detail. 6 to 9 are cross-sectional views showing the details of the lower die 11, the upper die 17, and the forging material 3A of the brass material forging device 10 shown in FIGS. FIG. 10 is a stroke diagram of a die and a punch at the time of forging.

First, as shown in FIG. 6, a forged brass material heated to approximately 300 to 600 ° C. in the stepped forming hole 16 of the lower die 12 with the upper inner punch 21 and the upper outer punch 20 raised. Set 3A. However, during the following forging, the brass material 3A is formed while maintaining the temperature at 550 ° C. or lower. Here, the volume of the brass material 3A is set to be equal to the net volume of the spout tip metal fitting 3 in order to realize the burr-free molding.

Next, as shown in FIG. 7, the upper die 19 is lowered to bring the lower surface of the upper die 19 into contact with the upper surface of the lower die 12, and the upper die 17 is clamped to the lower die 11. This mold clamping is performed by switching the electromagnetic direction switching valve 42 shown in FIG. 5 to extend the piston rod 22a of the second hydraulic cylinder 22 and lower the upper slide 18. In this clamped state, the lower end of the upper outer punch 20 and the lower end of the upper inner punch 21 form the same plane and are closely opposed to the upper end surface of the brass material 3A. This state is
This corresponds to times t1 to t2 in FIG.

Next, the set pressure of the electromagnetic proportional relief valve 45 is set to a high pressure, and the holding force (pressing force,
Or, the supporting force is set high. At the same time, the first hydraulic cylinder 14 is operated by operating the electromagnetic directional switching valve 43 so that the upper end of the die pin 13 is flush with the lower end of the step forming hole 16 as shown in FIG.
3 height position is set. When the position of the die spin 13 is determined, the electromagnetic direction switching valve 43 is switched to the block position a.

Next, the upper outer punch 20 and the upper inner punch 21 are integrally driven downward to bring the volume of the molding cavity C substantially equal to the volume of the brass material 3A as shown in FIG. The brass material 3A is formed. In this state, portions other than the concave and convex portions 7 (see FIG. 9) (that is,
The forming (pre-forging step) of the fitting portion 4, the flange portion 5, and the stepped fitting portion 6) is completed. During this molding, in a state where the set pressure of the electromagnetic proportional relief valves 45 and 46 is set to a high pressure, the electromagnetic direction switching valves 42 and 44 are switched so that the piston rod 22 a of the second hydraulic cylinder 22 and the third hydraulic cylinder 23 The piston rod 23a is driven down synchronously.

During the pre-forging step, the electromagnetic directional control valve 43 is held at the block position a. Since the hydraulic oil is an incompressible fluid, the first hydraulic cylinder 14
The oil pressure in the head side oil chamber (lower oil chamber) is maintained high,
The die spin 13 does not retreat downward. Therefore, in the pre-forging step, the brass material 3A is formed into an intermediate molded body 3B as shown in FIG. 8 (or FIG. 3) by closed die forging.
Mold into This state corresponds to times t2 to t3 in FIG.

Next, as shown in FIG. 9, the upper inner punch 21 is driven to descend, and the die spin 13 is moved backward. As a result, the concavo-convex portion 7 is formed continuously with the pre-forging step. During this deep hole forming, the electromagnetic proportional relief valve 45 is switched to a set pressure lower than the pressing force of the upper inner punch 21, and the electromagnetic direction switching valve 43 is moved to the rod retreat position b.
Further, the holding force (back pressure) of the die pin 13 is held low via the throttle 43a at the rod retreat position b of the electromagnetic direction switching valve 43. This state corresponds to time t3 in FIG.
~ T4.

The set pressure of the electromagnetic proportional relief valve 45 is set sufficiently low, and the degree of throttle of the throttle 43 a of the electromagnetic direction switching valve 43 is set appropriately in relation to the lowering speed of the upper inner punch 21. The first hydraulic cylinder 1
The oil pressure in the head side oil chamber of No. 4 can be kept low. The lowering force of the upper inner punch 21 is appropriately set via the electromagnetic proportional relief valve 46, and the set pressure is set to a relatively low pressure at which molding is possible.

In the deep hole forming step, the concavo-convex portion 7 is formed by using the material of the lower part of the upper inner punch 21 of the intermediate formed body 3B shown in FIG.
For this reason, the volume of the brass material in the same portion is set so as to be substantially equal to the net volume of the uneven portion 7. If this condition is satisfied, the position of the upper end of the die spin 13 when molding the intermediate molded body 3B is not limited to the position shown in FIGS. 7 and 8, but is slightly higher than the position shown. It may be set or slightly lower.

After the completion of the forging, the upper die 17 is returned to the upper limit position. Next, the die cylinder 13 is raised by the hydraulic cylinder 14 to the upper limit position. As a result, the molded spout tip metal fitting 3 is ejected and the lower mold 1 is ejected.
Remove from 1.

According to the forging method described above, the following operations and effects can be obtained. (1) In the pre-forging step, while the holding force of the die spin 13 is set sufficiently high and the die spin 13 is held at a predetermined position, the volume of the molding cavity C is reduced to 3
A (cavity C)
The brass material 3A is formed (until the forging material is filled in the inside), and the formation of the portions other than the concave and convex portions 7 (the fitting 4, the flange 5, the stepped fitting 6) is completed. Therefore, before starting the forming of the concave-convex portion 7, the portion other than the concave-convex portion 7 can be accurately molded with almost no burrs. In particular, since portions other than the uneven portion 7 can be upset-formed in the same manner as forging under hydrostatic pressure, cracking defects caused by a frictional force acting between the brass material and the lower die 12 hardly occur.

(2) In the pre-forging step, die spin 1
In a case where the piston rod 14a of the hydraulic cylinder 14 is configured to be able to retreat while maintaining a high holding force for holding the brass material 3, the weight variation of the brass material 3A can be absorbed by the retraction of the piston rod 14a.

(3) In the deep hole forming step, the uneven portions 7
Continuing with the molding of the other parts, the upper inner punch 21 is driven downward to drive the punch 21 into the forged material 3A with the parts other than the concave and convex portions 7 sealed in the mold. At this time, the holding force of the die spin 13 is switched to a lower level, and the concave / convex portion 7 is formed while the die spin 13 is retracted with the back pressure applied. Therefore, since the brass material does not flow upward during the formation of the uneven portion 7, the uneven portion 7 can be formed accurately and without burrs without excessively increasing the pressing force of the upper inner punch 21.

(4) In the deep hole forming step, the brass material does not flow upward during the formation of the uneven portion 7, so that the edge portion 16
The entrapment defect due to the difference in the flow of the brass material in a is less likely to occur. Therefore, it is possible to form a sharp portion having the edge portion 16a. In addition, the material does not flow upward during the formation of the uneven portion 7, and the frictional force between the brass material and the lower die 13 generated at the time of the flow does not increase the resistance. There is no need to increase the height, and the upper inner punch 21 is less likely to buckle, and the durability is improved.

(5) The first hydraulic cylinder 14 is used as holding means for holding the die pin 13, and the holding force of the die pin 13 is changed by changing the oil pressure of the oil chamber on the head side of the first hydraulic cylinder 14. 13 can be appropriately adjusted. (6) Since the brass material is forged while being maintained at a temperature of 550 ° C. or lower, forging can always be performed with a constant deformation resistance even in a part shape in which the depth of the concave portion 7a is deep and the forging time is long. Note that the temperature of 550 ° C. is equal to or lower than the tempering temperature of hot tool steel (JIS SKD61 or the like) usually used for this type of mold, and therefore, the durability of the mold can be sufficiently ensured.

In the die forging method described above, brass having good workability is one of the preferable forging materials.
However, there is a problem in that conventional brass has a problem in corrosion resistance and the like as compared with bronze when used as a water supply equipment part for a house. However, if the molded article after cooling is at least one of the following crystal structures (1) to (3), problems such as corrosion resistance fall within an acceptable level.

(1) The area ratio of the α + β phase and the β phase is 15
% Or more, preferably 20% or more, the average crystal grain size of the α phase and the β phase is 15 μm or less, and the Sn concentration in the β phase is 1.5 wt% or more. (2) The area ratio of the α + γ phase and the γ phase is 3 to 30%, the average crystal grain size of the α phase is 15 μm or less, the average crystal grain size (minor axis) of the γ phase is 8 μm or less, and γ A crystal structure in which the Sn concentration in the phase is 8 wt% or more and the γ phase is scattered at the grain boundaries of the α phase. (3) The area ratio of α + β + γ phase and α phase is 40 to 94
%, The area ratio of the β phase and the α phase is 3 to 30%, the average crystal grain size of the α phase and the β phase is 15 μm or less, and the average crystal grain size (minor axis) of the γ phase is 8 μm or less. Therefore, the Sn concentration in the γ phase is 8 wt% or more,
Crystal structure surrounding the phase. (4) Any one of the crystal structures of the α + β phase, the α + γ phase, and the α + β + γ phase, and the area ratio of the α phase is 4
4 to 80%, the area ratio of the β phase is 0 to 55%, the area ratio of the γ phase is 0 to 50%, the average particle size of the α phase, the β phase, and the γ phase is 15 μm or less; , A crystal structure in which the γ phase is dispersed.

According to the crystal structures (1) to (3),
The first feature is that the Japan Copper and Brass Association Technical Standard (JBMA)
In the dezincification corrosion test according to T-303), the maximum zinc removal depth is 100 μm or less when parallel to the processing direction, and 70 μm or less when perpendicular to the processing direction.
As a second feature, when the cylindrical sample is exposed to an ammonia atmosphere on a 14% aqueous ammonia solution under a load of stress 180 N / mm ² for 24 hours, the sample has no SCC resistance that the sample is not broken.

As a third feature, it has a 0.2% proof stress or yield stress of 300 N / mm ² or more. As a fourth feature, it has erosion corrosion resistance.

In order to obtain the above crystal structure, for example, the apparent Zn content is 37 to 50 wt%, and the Sn content is 0.5 to 7 wt%, preferably 1.7 to 2.2 w%.
A brass material having a composition of t% is used. The addition of Sn can improve the corrosion resistance and improve the strength of the material by including Sn in the β phase having poor corrosion resistance. Here, “apparent Zn content”
The terms A are Cu content (wt%), B is Zn content (wt%), and a third element to which t is added (for example, Sn).
When the Zn equivalent and Q of the above are the content (wt%) of the third element, “{(B + tQ) / (A + B + tQ)} ×
100 ”.

The brass material having the above composition has a short axis average crystal grain size of 15 μm in the crystal structure of the forged material during forging.
Those having the following γ phase are preferred. Due to such a crystal structure during processing, sufficient ductility of the forged material can be ensured even when plastic deformation occurs while recrystallization occurs in a low temperature range of 300 to 550 ° C. In particular, by precipitating the γ phase in the β phase, the crystal grains of the γ phase can be further refined and the deformability can be increased, which is desirable. By setting the temperature difference between the start of forging and the end of forging within 20 degrees, the ductility of the material can be made substantially constant between the start of processing and the end of processing, and the formability of the forged material is improved.

The temperature difference between the forged material and the punch or die is set to 20 ° C. or less, or the punch or die is
Heating to 50 ° C. is also preferable from the viewpoint of improving moldability. In order to control the temperature of the punch or the die in this manner, for example, a heater and a temperature sensor may be incorporated in the punch or the die, and the amount of heat generated by the heater may be controlled by a temperature controller based on a detection signal output from the temperature sensor. it can.

Next, a second embodiment will be described. FIG.
FIG. 1 is a sectional view showing a structure of a pedestal formed by a die forging method according to a second embodiment of the present invention. FIG.
It is sectional drawing which shows the intermediate forging of the pedestal. The pedestal 50 in this example has a short tubular shape and has a pedestal portion 51 and a step portion 52 fixed to a predetermined mounting surface. To form the pedestal 50, first, the intermediate forged product 50B is forged. The intermediate forged product 50B has a base portion 5 having a bottom 53 and an edge 54a.
4 and a step original shape portion 55. This intermediate forged product 50B
The bottom 53 and the edge 54a of the pedestal prototype 54 are removed by cutting or the like to obtain the pedestal shown in FIG.

FIGS. 13 to 17 are sectional views schematically showing an apparatus for forging the pedestal intermediate forged product of FIG. 12 and a forging process. This brass material forging device has a lower die and an upper die corresponding to the lower die. The lower die has a lower die 12 and an ejector pin 15 which slides up and down through a pin insertion hole of the lower die 12.
Having. The upper die has an upper die 19 and an upper punch 24 that slides up and down by a cylinder through a punch insertion hole of the upper die 19. The lower die 12 is fixed, and the upper die 19 is moved up and down between the mold opening state and the mold clamping state.

The upper surface of the lower die 12 has a stepped hole 1
2a is formed. The stepped forming hole 12a is formed by the step original shape portion 55 and the base original shape portion 5 of the pedestal intermediate forged product 50B.
4 is formed. This stepped hole 12
The portion 12b surrounded by a is located higher than the upper surface of the other lower die 12. A portion 24a of the lower surface of the upper punch 24 facing the stepped forming hole 12a is formed in a concave shape. When the mold is clamped, the recess 24 a of the upper punch 24 communicates with the stepped hole 12 a of the lower die 12.

Next, the forging process will be described. First, as shown in FIG. 13, in a state where the mold is opened, the heated forged material 50A is inserted into the stepped hole 12 of the lower die 12.
It is set on the portion 12b surrounded by a. At this time,
The upper punch 24 is located at a position retracted from the lower surface of the upper die 19.

Next, as shown in FIG.
Then, the punch 24 is lowered at the same time, and the lower surface of the upper die 19 and the upper surface of the lower die 12 are brought into contact with each other to close the mold. During this time, the ejector pin 15 is in a predetermined position (the upper surface is the lower die 1).
2 is located on the same plane as the second plane). The forged material 50A undergoes flow deformation, and the bottom 53 of the intermediate forged product 50B.
, A prototype 54 ′ of the pedestal prototype 54, and a part of the prototype 55 ′ of the step prototype 55.

Next, as shown in FIG. 15, only the upper punch 24 is further lowered, and the space formed by the lower die 12, the upper die 19, and the upper punch 24 becomes a forged material 50.
The volume should be approximately the same as the volume of A. In this process, the forged material 50A is filled in each part, and an intermediate forged product 5 having a bottom 53, a pedestal prototype 54, and a step prototype 55 is provided.
OB is molded.

After the completion of the forging, the upper die is returned to the upper limit position as shown in FIG. Subsequently, as shown in FIG. 17, the eject pin 15 is raised to discharge the intermediate forged product 50B. Finally, the bottom 53 and the edge 54a of the pedestal prototype 54 are removed from the intermediate forged product 50B by cutting or the like to obtain the final pedestal 50.

According to the die forging method of this example, the punch 24
By forming the hole which becomes the bottom 53 and the step original shape part 55 with, and continuously forming the pedestal part original shape part 54 around the hole by the punch 24, the supply of the material from the central part to the periphery becomes smooth, Formability is improved.

Next, a third embodiment will be described. FIG.
FIG. 8 is a view showing the structure of an impeller according to a third embodiment of the present invention, wherein FIG. 18 (A) is a plan view and FIG. 18 (B) is a sectional view. FIG. 19 is a diagram showing a structure of an intermediate forged product of the impeller of FIG. 18, in which FIG. 19 (A) is a plan view and FIG. 19 (B).
Is a sectional view. The impeller 60 of this example has a hub portion 61 and a blade portion 62, and a shaft hole 63 passes through the center. To form the impeller 60, first, the intermediate forged product 60B is forged. The intermediate forged product 60B includes an outer burr 62a, an end burr 63a, a material placing step 62b, and a punch step 6
2c. Outer part 62 of this intermediate forged product 60B
a, the material placing step 62b, the punch step 62c, and the end face burr 63a are removed by cutting or the like to obtain the impeller shown in FIG.

20 to 26 are sectional views schematically showing an apparatus for forging the impeller intermediate forged product of FIG. 19 and a forging process. This brass material forging device has a lower die and an upper die corresponding to the lower die. The lower die is a lower die 12 and an ejector pin 1 that slides vertically through a pin insertion hole of the lower die 12.
5 The upper die has an upper die 19 having an upper outer punch 20 and an upper inner punch 21. The upper outer punch 20 is not connected to the driving source, and the upper die 1
Nine punch insertion holes are slidably arranged vertically.
The lowering of the upper outer punch 20 is locked by the locking surface 19 b of the upper die 19. The upper inner punch 21 slides up and down through a punch insertion hole of the upper outer punch 20. The lowering of the upper inner punch 21 is locked by the locking surface 20 a of the upper outer punch 20.

The upper surface of the lower die 12 has a stepped hole 1
2a is formed. The stepped forming hole 12a is formed in the outer bur portion 62a of the intermediate forged product 60B and the material placing step portion 62.
b, for forming the punch step 62c and the end face burr 63a. A stepped hole 19a is also formed on the lower surface of the upper die 19 at a portion facing the stepped hole 12a. When the mold is clamped, these stepped holes 12a and 19a communicate with each other.

Next, the forging process will be described. First, as shown in FIG. 20, the heated forged material 60A is set in the stepped hole 12a of the lower die 12 with the mold opened. Next, as shown in FIG.
The lower die 9 and the upper inner punch 21 are simultaneously lowered, and the lower surface of the upper die 19 contacts the upper surface of the lower die 12 to clamp the mold. At this time, the lower surface of the upper outer punch 20 abuts on the upper surface of the forged material 60A and is locked. No load is applied to the upper outer punch 20, and the punch 20 retreats relatively to the upper die 19.

Next, as shown in FIG. 22, the upper inner punch 21 is lowered until it comes into contact with the locking surface 20a of the upper outer punch 20. Here, the end face burr 6 of the shaft hole 63
A part of 3a is formed. At this time, the upper outer punch 2
0 remains in contact with the forged material 3A.

Next, as shown in FIG. 23, the upper inner punch 21 is further lowered. At this time, the upper inner punch 21 is locked on the locking surface 20 a of the upper outer punch 20, and the upper outer punch 20 and the upper inner punch 21 are simultaneously lowered, and the upper outer punch 20 is locked on the locking surface 19 b of the upper die 19. Abut At this time, a shaft hole 63 is formed. At the same time, the forged material flows and deforms and is filled into each stepped forming hole, and the outer portion 62a
To completely form the end face burrs 63a. At the same time as inserting the upper inner punch 21 to completely form the shaft hole 63 and further compressing the upper outer punch 20 to form the hub portion 61, the material is pushed and spread from the center toward the outer periphery, The spread of the material becomes uniform, and the moldability is improved.

After the completion of the forging, as shown in FIG. 24, the upper inner punch 21 is pulled out of the forged product. Thereafter, the upper die is returned to the upper limit position as shown in FIG. At this time, the upper outer punch 20 also rises at the same time. continue,
As shown in FIG. 26, the eject pin 15 is raised to discharge the intermediate forged product 60B. In addition, a part 12c of the lower die 12 also rises similarly to the eject pin 15,
Help discharge the intermediate forged product 60B. Then, the outer burr 6
2a, the end burr 63a, the material placing step 62b, and the punch step 62c are removed by cutting or the like to obtain the final impeller 60.

In the die forging method according to the third embodiment, the upper inner punch 21 (first punch) is driven in parallel with the driving of the upper inner punch 21 (first punch) into the forging material 60A.
The upper outer punch 20 without retreating the (first punch)
The forged material is processed by (second punch or die). For this reason, there is an advantage that the part formed by the upper inner punch 21 (first punch) does not collapse.

Next, a fourth embodiment will be described. FIG.
7 to 33 are cross-sectional views schematically showing an apparatus and a forging process according to another embodiment for forging the impeller intermediate forged product of FIG. This brass material forging device has a lower die and an upper die corresponding to the lower die. The lower die is a lower die 12 and an ejector pin 1 that slides vertically through a pin insertion hole of the lower die 12.
5 The upper die has an upper die 19 having an upper outer punch 20 and an upper inner punch 21. The upper outer punch 20 is not connected to the driving source, and the upper die 1
Nine punch insertion holes are slidably arranged vertically.
The lowering of the upper outer punch 20 is locked by the lower locking surface 19 a of the upper die 19, and the rising is locked by the upper locking surface 19 b of the upper die 19. The upper inner punch 21 slides up and down through a punch insertion hole of the upper outer punch 20. The lowering of the upper inner punch 21 is locked by the locking surface 20 a of the upper outer punch 20.

The upper surface of the lower die 12 has a stepped hole 1
2a is formed. The stepped forming hole 12a is formed in the outer bur portion 62a of the intermediate forged product 60B and the material placing step portion 62.
b, for forming the punch step 62c and the end face burr 63a. A stepped hole 19b is also formed on the lower surface of the upper die 19 at a portion facing the stepped hole 12a. When the mold is clamped, these stepped holes 12a and 19b communicate with each other.

Next, the forging process will be described. First, as shown in FIG. 27, the heated forged material 60 </ b> A is set in the stepped forming hole 12 a of the lower die 12 with the mold opened. The upper outer punch 20 is located on the lower locking surface 19 a of the upper die 19. Next, as shown in FIG. 28, the upper die 19 and the upper inner punch 21 are simultaneously lowered, and the lower surface of the upper die 19 is brought into contact with the upper surface of the lower die 12. However, no mold clamping is performed at this time. Lower surface of upper outer punch 20 is forged material 60A
Is brought into contact with the upper surface of the lock. The punch 20 retreats from the upper die 19 to the upper locking surface 19 b of the upper die 19. The forged material 60A is pressed by the upper inner punch 20 and the upper die 19 to flow and deform, and a portion 62 ′ of the blade portion starts to be formed by the amount of the forged material protruding in the outer peripheral direction. At the same time, the end burr portion 63a starts to be formed.

Next, as shown in FIG. 29, the upper inner punch 21 is lowered until it comes into contact with the locking surface 20a of the upper outer punch 20. Here, the end face burr 6 of the shaft hole 63
A part of 3a is formed. At the same time, a part 62 'of the blade is further molded. At this time, due to the movement of the material extruded by the upper inner punch 21, the upper outer punch 20 retreats, and the unmolded upper die also retracts.

Next, as shown in FIG. 30, the upper inner punch 21 is further lowered. At this time, the upper inner punch 21 is locked on the locking surface 20a of the upper outer punch 20, and the upper outer punch 20 and the upper inner punch 21 are simultaneously lowered. Further, the upper die 19 is also lowered and the mold is clamped. At this time, a shaft hole 63 is formed. At the same time, the forged material flows and deforms, is filled in each stepped forming hole, and completely forms the blade portion 62 with the material that protrudes to the outer periphery,
The end face burrs 63a are completely formed. Furthermore, the shaft hole 63 is completely formed by inserting the upper inner punch 21. At the same time as the work of forming the hub portion 61 by compressing with the upper outer punch 20, the material is pushed and spread from the center to the outer peripheral direction, so that the spread of the material becomes uniform and the formability is improved. In these processes, the upper inner punch 21 is still inserted, and the shaping of the shaft hole 63 is ensured.

After the completion of the forging, as shown in FIG. 31, the upper inner punch 21 is pulled out of the forged product. Thereafter, the upper die is returned to the upper limit position as shown in FIG. At this time, the upper outer punch 20 also rises at the same time. continue,
As shown in FIG. 33, the eject pin 15 is raised to discharge the intermediate forged product 60B. In addition, a part 12c of the lower die 12 also rises similarly to the eject pin 15,
The intermediate forged product 60B is discharged. Thereafter, the outer part 62
a, the end face burr portion 63a, the material placing step portion 62b, and the punch step portion 62c are removed by cutting or the like to obtain the final impeller 60.

In the die forging method according to the fourth embodiment, the upper inner punch 21 (first punch) is provided on the forged material.
The forging material is processed by the upper outer punch 20 (the second punch or the die) without retreating the upper inner punch 21 (the first punch) in parallel with the driving. For this reason, the upper inner punch 21 (first punch)
There is an advantage that the molded part due to is not collapsed.

Next, a fifth embodiment will be described. FIG.
FIGS. 4 to 37 are cross-sectional views schematically showing an apparatus and a forging process according to another embodiment for forging the impeller intermediate forged product of FIG. This brass material forging device has a lower die and an upper die corresponding to the lower die. The lower die is a lower die 12 and a die pin 1 that slides up and down through a punch insertion hole of the lower die 12.
3. It has an ejector pin 15 that slides up and down the pin insertion hole of the lower die 12. The upper die includes an upper die 19 and an upper punch 24 that slides up and down through a punch insertion hole of the upper die 19.
Having. The lowering of the upper punch 24 is locked by the lower locking surface 19 b of the upper die 19.

On the upper surface of the lower die 12, a stepped hole 1 is formed.
2a is formed. The stepped forming hole 12a is formed in the outer bur portion 62a of the intermediate forged product 60B and the material placing step portion 62.
b, for forming the punch step 62c and the end face burr 63a. A stepped hole 19a is also formed on the lower surface of the upper die 19 at a portion facing the stepped hole 12a. When the mold is clamped, these stepped holes 12a and 19a communicate with each other.

Next, the forging process will be described. First, as shown in FIG. 34, the heated forged material 60 </ b> A is set in the stepped hole 12 a of the lower die 12 in the mold open state. At this time, the upper surface of the die spin 13 is located on the same plane as the surface of the step forming hole 12a, and is set to a lower holding force. Next, as shown in FIG. 35, the upper die 19 and the upper punch 24 are simultaneously lowered, and
The upper surface of the lower die 12 is brought into contact with the upper surface of the lower die 12 to clamp the mold.
At this time, the forged material flows and deforms to fill each forming hole,
The blade 62 is completely formed. At the same time, die spin 1
In No. 3, the forging material 60A is pushed in by a relatively low holding force (back pressure) and slightly retreats. Here, the end face burrs 63a are partially formed.

Next, as shown in FIG.
Is lowered until it comes into contact with the locking surface 19 a of the upper die 19. At the same time, the die spin 13 retreats. Here shaft hole 6
3 is completely formed. By forming the shaft hole 63 with the upper punch 24 after the blade 62 is completely formed, the outer shape of the blade 62 can be accurately formed.

After the forging is completed, as shown in FIG. 37, the upper punch 24 is pulled out of the forged product. Thereafter, the upper die is returned to the upper limit position. Subsequently, the eject pin 15 is raised to discharge the intermediate forged product 60B. Thereafter, the outer burr 62a, the end burr 63a, the material placing step 62b, and the punch step 62c are removed by cutting or the like to obtain the final impeller 60.

In the die forging method according to the fifth embodiment, an upper die 19 (a die for forging the outer shape of a molded product) and an upper punch 24 (a punch for molding a concave portion of the molded product) are viewed from the same direction. The forging is performed by pressing against the forging material 60A, and the die spin 13 is retracted while applying a back pressure during the forging. Therefore, a product having a complicated shape such as an impeller can be formed.

Further, in this embodiment, the upper die 1
9 (mold) and the upper punch 24 (punch) are formed at different timings. If the mold and the punch (or a plurality of punches) are operated integrally, there may be a problem that the meat near the base of the upper punch 24 (punch) becomes missing during forging. However, such problems can be prevented by using both at different timings or by using a plurality of punches at different timings.

Next, a sixth embodiment will be described. FIG.
8 is a view showing a structure of a water meter formed by a die forging method according to a sixth embodiment of the present invention, wherein FIG. 38 (A) is a front sectional view, and FIG. 38 (B) is a partial sectional plan view. is there. 39 is a diagram showing a structure of an intermediate forged product of the water meter of FIG. 38, FIG. 39 (A) is a front sectional view, and FIG. 39 (B) is a partial sectional plan view. The water meter 70 in this example has a blade insertion portion 71 to which a rotary blade (not shown) is attached in the center, and a cap screw portion 72. Further, the insertion portion 71
And a flowing water outlet passage 74 extending downward and to the right and a flowing water inlet passage 73 extending downward and to the left. An outlet screw portion 74a and an inlet screw portion 73a are provided at the distal ends of the flowing water outlet passage 74 and the flowing water inlet passage 73. The intermediate forged product 70B is
As shown in FIG. 44, burr portions 74b and 73b are provided at the tip of the outlet screw portion 74a and the inlet screw portion 73a, respectively.
Further, burrs 74c and 73c are provided at positions where the respective flowing water passages enter the insertion section 71. This burr part 7
4b, 73b, 74c and 73c are removed by cutting or the like to obtain a finished water meter 70.

FIGS. 40 to 48 are views schematically showing an apparatus for forging the water meter intermediate forged product of FIG. 39 and a forging process. FIG. 40 is a side sectional view of this forging device, FIG. 41 is a plan view, and FIG. 42 is a side sectional view of AA section. This brass material forging device has a lower die and an upper die corresponding to the lower die. The lower die has a lower die 12, left and right side punches 226 and 227, a middle punch 228, and an ejector pin 15 that slides up and down through a pin insertion hole. As shown in FIG. 45, the left and right side punches 226 and 227 slide through punch insertion holes formed on the left and right sides of the lower die 19. The middle punch 228 slides through a punch insertion hole formed in the front of the lower die 19, as shown in FIG. As shown in FIG. 41, the left and right punch insertion holes are located on a straight line on the horizontal cross section, and the middle punch insertion hole and the left and right punch insertion holes are located at right angles on the horizontal cross section. Further, the left punch insertion hole and the right punch insertion hole are inclined outward and downward.

On the upper surface of the lower die 12, a stepped hole 1 is formed.
2a is formed. A portion of the lower surface of the upper die 19 facing the stepped hole 12a is provided with a stepped hole 19a.
a is formed. When the mold is clamped, these stepped holes 12a and 19a communicate with each other.

The upper die 19 has a built-in heater (not shown). As shown in FIG. 42, a heat insulating material is wound around the outer periphery of the lower die 12 and the upper die 19.
The die mating surface of each die is covered with a heat insulating material 229 and a SUS plate 230 to keep the temperature.

Next, the forging process will be described. First, as shown in FIG. 43, the heated forged material 70 </ b> A is set on the step forming hole 12 a of the lower die 12 in the mold open state. Next, as shown in FIG. 44, the upper die 19 is lowered and brought into contact with the lower die 12 to perform mold clamping. Next, as shown in FIG. 45, the middle punch 228 is inserted. At this time, the forged material 70A undergoes flow deformation, and the blade insertion portion 71 and the cap screw portion 72, and the respective flowing water passages 74 ', 7
Part of 3 'is molded. Medium punch 228 after insertion is complete
Has a holding force. Subsequently, as shown in FIG. 46, the left side punch 226 and the right side punch 227 are simultaneously inserted to the locking surface. Here, the thread portions 74b and 73b and the burr portions 74c and 73c of each flowing water path are formed.

After this forging is completed, as shown in FIG.
The middle punch 228, the left side punch 226, and the right side punch 227 are retracted. Thereafter, the upper die is returned to the upper limit position as shown in FIG. Then, the ejector pin 15 is raised to discharge the intermediate forged product 70B. The intermediate molded product is processed by the above-described cutting process or the like, and unnecessary portions are removed to obtain a final molded product.

In the die forging method according to the sixth embodiment, an overhanging step of forming an overhang by forging;
And a forming step of forming the overhang portion into a predetermined shape by further forging the overhang portion, and the two steps are performed in the same mold.

In the forming step, the left and right side punches 22
6, 227 (punch, etc.), so that the filling of the material is better than molding by overhang only. Also,
Since the overhanging step and the forming step are performed in the same mold, the number of types of the mold can be reduced, and the cost of the mold is not required. Further, the productivity is high because there is no need to transfer the forged material to another press during forging.

This final molded article has SCC resistance. FIG. 49 is a diagram showing an SCC resistance test apparatus. The SCC resistance is a property that a sample does not crack when exposed to an ammonia atmosphere on a 14% aqueous ammonia solution for 24 hours while applying a load of 180 N / mm ² stress. This SCC resistance test is evaluated by exposing the cylindrical sample 232 in a glass desiccator 231 to a NH ₃ vapor atmosphere for 24 hours while applying a vertical load, and then examining the occurrence of cracks.

Further, it has eco-erosion corrosion resistance. FIG. 50 is a diagram illustrating an eco-resistance test apparatus. The resistance to eco-erosion was determined by using a cylindrical sample 53 having an orifice 233 inside, and flowing water through the orifice 233 at a flow rate of 40 m / sec for a predetermined period of time.
The tightening torque to the resin stopper 234 required to seal the orifice 233 was measured under a water pressure of 05 Pa (Kg / cm ² ).

FIG. 51 is a graph showing the results of the eco-erosion resistance test. As a result, as shown in FIG. 51, better characteristics were obtained than the conventional brass material.

Next, a seventh embodiment will be described. FIG.
2 is a diagram showing a structure of a throw-away shaft formed by a die forging method according to a seventh embodiment of the present invention, wherein FIG. 52 (A) is a perspective view and FIG. 52 (B) is a cross-sectional view. FIG. 53 is a view showing the structure of the intermediate forging of the throwaway shaft of FIG.
(A) is a perspective view, and FIG. 53 (B) is a cross-sectional view. The intermediate forged product 80 of this example has a shaft portion 81, an upper small diameter portion 82, a large diameter portion 83, and a lower small diameter portion 84. The intermediate forging 80B has a disposal margin 80a protruding from the lower small diameter portion 84. The waste 80a is removed by cutting or the like to obtain a final intermediate forged product 80.

FIGS. 54 to 56 are sectional views schematically showing a device for forging the intermediate shaft forged product of FIG. 53 and a forging process. This brass material forging device has a lower die and an upper die corresponding to the lower die. The lower die has a lower die 12 and a die pin 13 that slides up and down through a pin insertion hole of the lower die 12. The upper die has an upper die 19, and an upper outer punch 20 is provided integrally.

The upper surface of the lower die 12 has a stepped hole 1.
2a is formed. The upper outer punch 20 is fitted into the upper stepped hole 12a. On the lower surface of the upper outer punch 20, a stepped forming hole 20b is formed.

Next, the forging process will be described. First, as shown in FIG. 54, in a state where the mold is opened, the heated forging material 80A is placed in the stepped hole 12 on the lower die 12.
Set in a. Next, as shown in FIG. 55, the upper die 19 is lowered, and the lower surface of the upper outer punch 20 is brought into contact with the upper surface of the forging material 80A. At this time, the lower surface of the upper die 19 is not in contact with the upper surface of the lower die 12. A holding force is applied to the die spin 13. In this state,
The upper outer punch 20 fluidly deforms the forged material 80A, and forms a part of the shaft portion 81, an upper small diameter portion 82, a large diameter portion 83, and a lower small diameter portion 84.

Further, as shown in FIG.
9 is lowered, and the lower surface of the upper die 19 and the upper surface of the lower die 12 are brought into contact with each other to clamp the mold. At this time, die spin 13
Load of forging material applied to die spin 1
When the holding force becomes larger than the holding force of 3, the excess forging material 3A overcomes the holding force of the die spin 13 and retreats the die spin 13. At this time, the surplus forging material 80A flows into the pin insertion hole of the lower die 12 to form a waste 80a.
Further, it also flows into the shaft portion 81 to completely form the shaft portion 81. Finally, the upper die 19 is raised and the die spin 13
And discharge the molded product.

During the forming, a holding force larger than the load applied to the die spin 13 when the forging material 80A is filled in the forming hole is applied to the die spin 13. For this reason, the forged material 80A is reliably filled into the details of the molding hole, and the excess material flows into the pin insertion hole, so that no underfill occurs. Further, since the retreated portion meat is entirely removed in the subsequent step, the surplus material does not adversely affect the accuracy. Further, since the holding force of the die spin 13 can be set to be adjustable by a hydraulic cylinder, the load applied to the die spin 13 when the forging material 80A is filled in the forming hole can be easily grasped. Therefore, forging can be performed with a minimum necessary forming force.

Further, when the forging becomes full during the forging, the holding force of the die spin 13 is set to a low level, so that the surplus forging material 80A comes into contact with the die spin 13 and overcomes the holding force of the die spin 13. . And since it flows into the pin insertion hole while moving the die spin 13,
There is no interruption of forging due to the sealed high pressure state, and the load on the mold can be reduced.

Next, an eighth embodiment will be described. FIG.
FIG. 7 is a view showing a structure of a disposal shaft formed by a die forging method according to an eighth embodiment of the present invention, wherein FIG. 57 (A) is a perspective view and FIG. 57 (B) is a sectional view. FIG. 58 is a diagram showing the structure of the intermediate forging of the throwaway shaft of FIG.
(A) is a perspective view, and FIG. 58 (B) is a cross-sectional view. The intermediate forged product 90 has an edge 91, a hole 92, and a shaft 93.
The intermediate forged product 90B has a disposal margin 90a protruding from the shaft portion 93. The final allowance 90a is removed by cutting or the like to obtain a final intermediate forged product 90.

FIGS. 59 to 62 are sectional views schematically showing a device for forging the intermediate shaft forged product of FIG. 58 and a forging process. This brass material forging device has a lower die and an upper die corresponding to the lower die. The lower die has a lower die 12 and a die pin 13 that slides up and down through a pin insertion hole of the lower die 12. The upper die has an upper die 19 and an upper punch 24 that slides up and down through a punch insertion hole of the upper die 19.

On the upper surface of the lower die 12, a stepped hole 1 is formed.
2a is formed. A portion of the lower surface of the upper die 19 which faces the stepped forming hole 12a is provided with a stepped forming hole 19a.
a is formed. When the mold is clamped, the stepped holes 19a and 12a communicate with each other.

Next, the forging process will be described. First, as shown in FIG. 59, in a state where the mold is opened, the heated forged material 90A is formed into the stepped hole 12a of the lower die 12.
Set inside. At this time, the upper surface of the die spin 13
It is located on the same plane as the surface of the stepped forming hole 12a. next,
As shown in FIG. 60, the upper die 19 and the upper punch 24 are simultaneously lowered, and the lower surface of the upper die 19 is brought into contact with the upper surface of the lower die 12 to clamp the mold.

Next, as shown in FIG.
Is lowered to the first stage. At this time, the forged material flows and deforms, and a part of the edge 91, the hole 92, and the shaft 93 are formed. Here, the die spin 1
3 and the holding force of the die spin 13 are equal,
The die spin 13 does not retreat. Further, as shown in FIG. 62, the upper punch 24 is lowered to the second stage. At this time, the load applied to the die spin 13 becomes larger than the holding force, and the excess forged material 90A overcomes the holding force of the die spin 13 and retreats the die spin 13. Here, the edge portion 91 is completely formed, and the surplus forging material 90A flows into the pin insertion hole, and a waste margin 90a is formed.

Lastly, the upper die is returned to the upper limit position, and the intermediate forged product is discharged. Thereafter, the discarding allowance 90a is removed by cutting or the like to obtain a final intermediate forged product 90.

Next, a ninth embodiment will be described. FIG.
3 is a diagram showing a structure of a hand shower support fitting formed by a die forging method according to a ninth embodiment of the present invention, FIG. 63 (A) is a plan sectional view, and FIG. 63 (B) is a side sectional view. is there. The hand shower support fitting 100 of this example has a cylindrical bottomed shape, a deep recess (first recess) 101 for inserting a hand shower, and a shallow recess (second recess) 102 having a larger diameter than this. It has two recesses. An overhanging portion 103 is provided at the open end, and a small protrusion 104 is provided at the closed end.

FIGS. 64 to 69 are sectional views schematically showing an apparatus for forging the hand shower support of FIG. 63 and a forging process. This brass material forging device has a lower die and an upper die corresponding to the lower die. The lower mold has a lower die 12 and
It has a die pin 13 that slides up and down the pin insertion hole of the lower die 12. The upper die has an upper die 19, an upper outer punch 20 and an upper inner punch 21. The upper outer punch 20 slides vertically between the lower locking surface 19b and the upper locking surface 19c of the upper die 19. Further, the upper outer punch 20 is urged upward by a spring 20c. The upper inner punch 21 slides up and down through the punch insertion hole of the upper outer punch 20.

On the upper surface of the die spin 13, a concave portion 13a is formed. The recess 13 is for forming the projection 104 of the hand shower support fitting 100.
On the lower surface of the upper die 19, a stepped forming hole 19a is formed.

Next, the forging process will be described. First, as shown in FIG. 64, the heated forged material 100A is set on the die spin 13 in the lower die 12 in the mold open state. At this time, the lower surface of the upper outer punch 20 urged upward and the lower surface of the upper inner punch 21 are positioned on the same plane as the lower surface of the die 19. Next, FIG.
As shown in FIG. 5, the upper die 19 and the upper inner punch 21
At the same time, the lower surface of the upper die 19 is
Abut the upper surface of the mold and clamp the mold. Next, as shown in FIG. 66, the die spin 13 is raised. At this time, the upper inner punch 21 is assisted to be located at the position shown in FIG. The forged material 100A undergoes flow deformation, and the overhang portion 10
3 is formed, and the projection 104 is formed on the end face. As described above, by providing the concave portion for molding in the die spin 13, a complicated shape can be molded.

Next, as shown in FIG. 67, the upper inner punch 21 is lowered. Here, molding of the deep concave portion 101 'is started. At this time, die spin 13 is forged material 1
Retract downward while applying back pressure to 00A. The die spin 13 descends by a volume equal to the pressed volume of the upper inner punch 21. Subsequently, as shown in FIG. 68, the upper inner punch 21 is further lowered. At this time, the upper inner punch 21 comes into contact with the upper outer punch 20, and the upper outer punch 20 also descends at the same time. Here, a shallow recess 102 is formed. The die spin 13 retreats while applying back pressure. As described above, by using two punches having different diameters in two stages, it is possible to form concave portions having different depths without obstructing the flow of the material.

Thereafter, as shown in FIG. 69, the upper inner punch 21 is raised. Thereafter, the upper die is returned to the upper limit position, and finally, the upper die 19 is raised to discharge the molded product.

By retracting the die spin 13 while applying a back pressure, flowback in which the integral in the concave portion of the forged material 3A is pushed up in the opposite direction to the upper inner punch 21 and the upper outer punch 20 does not occur, and the forged material 100A is continuously formed. It flows smoothly and smoothly. For this reason, a minute crack does not occur in the product. Further, since the pressing force of the punch may be substantially equal to the material processing force, the depth of the concave portion can be freely set without buckling of the punch.

Next, a tenth embodiment will be described. FIG. 70 is a side sectional view showing the structure of the flash valve lid formed by the die forging method according to the tenth embodiment of the present invention. The flash valve lid 110 in this example is concave and has a cylindrical portion 111 and a top portion 112. A knob 113 having an undercut is provided on the upper surface of the top 112. Further, a shoulder portion 114 is provided on the cylindrical portion 111.

FIGS. 71 to 77 are cross-sectional views schematically showing an apparatus for forging the hand shower support of FIG. 70 and a forging process. This brass material forging device has a lower die and an upper die corresponding to the lower die. The lower mold has a lower die 12 and
The lower die 12 has a lower punch 235 that slides up and down through a punch insertion hole. A collar 2 is provided on the outer periphery of the lower punch 235.
36 is attached and urged upward by a spring. The upper die has an upper die 19 and an upper punch 24 that slides up and down through a punch insertion hole of the upper die 19. A top 237 is provided on the outer periphery of the upper punch 24. The top 237 includes two parts 237a and 237b symmetrical in the axial direction of the upper punch 24, and is urged outward by a spring in a direction perpendicular to the axis.

The upper surface of the lower die 12 has a stepped forming hole 12.
a is formed. The lower surface of the top 237 is formed in a concave shape. Also, the division parts 237a and 237 of the frame 237
A concave portion 237c is provided in a portion facing b.
The recess 237c is for forming the knob 113 of the flash valve lid 110.

Next, the forging process will be described. First, as shown in FIG. 71, the heated forged material 110A is set on the lower punch 235 of the lower die 12 with the mold opened. The lower end surface of the top 237 is
Is located below the lower surface of the. Next, as shown in FIG. 72, the upper die 19 and the upper punch 24 are simultaneously lowered, and the lower surface of the top 237 is abutted on the upper surface of the lower die 12 and fixed. Here, the forged material 110A undergoes flow deformation to form the top portion 112 and the shoulder portion 114, and at the same time, the original shape portion 113 'of the knob 113 starts to be formed at the top portion.

Next, as shown in FIG.
Increase 5 The forged material 110A further flows and deforms, and the original shape portion 113 'of the knob 113 further grows upward. Further, a force higher than the holding force of the spring is also applied to the upper portion of the collar 236 of the lower punch 235, and the cylindrical portion 111 is completely formed. At this time, a back pressure is applied to the collar 236 by a spring, and the lower end of the cylindrical portion 111 is pressed to prevent the forged material from cracking.

Next, as shown in FIG.
Descends. At this time, the original shape of the knob 113 formed on the top 112 is crushed and protrudes to the side, and the knob (convex) 113 having an undercut is formed. By continuously forming the tubular portion 111 and the undercut knob 113 in this way, cracks in the tubular portion 111 and entrapment of the undercut surface layer are prevented, and forging defects are less likely to occur.

Thereafter, as shown in FIG.
35 falls. Then, as shown in FIG. 76, the upper die 19, the upper punch 24, and the top 237 rise integrally. The forged product rises together between the pieces 237. Finally, as shown in FIG. 77, the upper punch 24 descends with respect to the upper die 19. At this time, the top 237 is opened right and left by the bias of the spring, and the knob 113 is released.
The forged product 110 is reliably discharged.

In the die forging method according to the tenth embodiment, the lower punch 235 used to form the cylindrical portion 111 (cylindrical portion) when the forged product 110 (molded product) is taken out.
(Punch) is removed first, and after this B step, there is provided a C step of removing the molded product from the top 237 (die) used to form the outer peripheral surface of the cylindrical portion 111 (cylindrical portion). I have. For this reason, by lowering the pulling force of the lower punch 235 (punch) and the top 237 (die), it is possible to prevent deformation of the forged product 110 (molded product) and to reliably remove the molded product.

Next, an eleventh embodiment will be described. FIG. 78 is a side sectional view showing the structure of the H bush formed by the die forging method according to the eleventh embodiment of the present invention. H
The bush 120 has an H-shaped cross section, has an upper concave portion 121 and a lower concave portion 122, and has a flange 123 protruding outward on the outer circumference.

FIGS. 79 and 80 are sectional views schematically showing an apparatus for forging the H bush of FIG. 78 and a forging process. This brass material forging device has a lower die and an upper die corresponding to the lower die. The lower die has a lower die 19, a lower inner die spin 238 and a lower outer die spin 239. The lower outer die pin 239 slides up and down through the pin insertion hole of the lower die 19 and the lower inner die pin 23
8 slides up and down through the pin insertion hole of the lower outer die spin 239. The upper die has an upper die 12 and an upper punch 24 that slides up and down through a punch insertion hole of the upper die 12. Lower inner die spin 239, lower outer die spin 23
9. The upper punch 24 slides on the same axis.

The upper surface of the lower die 19 has a stepped hole 19.
a is formed. The stepped forming hole 19a is for forming the flange 123. On the lower surface of the upper die 12,
A step-forming hole 12a is formed in a portion facing the step-forming hole 19a. This stepped forming hole 12a
The upper concave portion 121 is formed.

Next, the forging process will be described. First, with the mold opened, the heated forged material 120A
Is set on the upper surface of the inner die spin 238 and the outer die spin 239 of the lower die 12. At this time,
The upper surface of each die spin is located on the same plane. Next, FIG.
As shown in FIG. 9, the upper die 19 and the upper punch 24 are simultaneously lowered to bring the lower surface of the upper die 19 into contact with the upper surface of the lower die 12, thereby clamping the mold. At this time, forged material 120A
Flows and deforms, and a part 121 ′ of the upper concave portion and the
Is molded.

Subsequently, as shown in FIG.
4 is further lowered, and at the same time, the outer die spin 239
Is lowered. At this time, the lowering volume of the upper punch 24 and the lowering volume of the outer die spin 239 are equal. The inner die spin 238 is held under a high holding pressure. Thereby, the lower concave portion 122 is formed. As described above, the upper punch 24 and the die spins 238 and 239 arranged coaxially can perform complicated forging having a concave portion on the upper and lower sides. Finally, the outer die spin 239 is raised to discharge the forged product.

Next, a twelfth embodiment will be described. FIG. 81 is a side sectional view showing the structure of a cheese formed by the die forging method according to the twelfth embodiment of the present invention. The cheese 130 has a T-shaped cross section and has passages 131 and 132 opened to the left and right, and a lower passage 133 opened downward perpendicular to the passage. To make this cheese 130,
First, after forming the intermediate forged product 130B (see FIG. 86), a final product is manufactured by cutting or the like. The intermediate forged product 3B is located at the center of the left and right passages 131 and 132 and the left and right passages 13 and 132.
It has a shape in which there is a wall between the first and the 132 and the lower passage 133.

FIGS. 82 to 86 are sectional views schematically showing an apparatus for forging the cheese of FIG. 81 and a forging process. This brass material forging device has a lower die and an upper die corresponding to the lower die. The lower die has a lower die 12, a left side punch 226, a right side punch 227, a ring 252, and a lower fixed punch 253. Left and right side punches 226, 2
27 slides coaxially through the left and right punch insertion holes of the lower die 12. The ring 252 is a fixed punch 2 of the lower die 12.
The outer periphery of 53 is slid up and down. The sliding direction of the ring 252 is perpendicular to the sliding direction of the left and right side punches.

On the upper surface of the lower die 12, a forming hole 12a is formed. A molding hole 19 a is formed on the lower surface of the upper die 19. These molding holes 12a and 19a communicate with each other when the mold is clamped.

Next, the forging process will be described. First, the heated forged material 130A is set on the upper surface of the fixed punch 253 and the ring 252 of the lower die 12 with the mold opened. At this time, the fixed punch 253 and the ring 2
The upper surface of 52 is located on the same plane. Next, as shown in FIG. 82, the upper die 19 is lowered, and the lower surface of the upper die 19 and the upper surface of the lower die 12 are brought into contact with each other to clamp the die. Next, as shown in FIG. 83, the left and right side punches 226 and 227 are simultaneously inserted for the first stage. At this time, forged material 130
A flows and deforms, and a part 131 ′, 132 ′ of the left and right passages
Is molded. Ring 252 is retained.

Next, as shown in FIG. 84, the left and right side punches 226 and 227 are inserted for the second stage. At this time, the ring 252 is retracted at the same time. Here, the volume for the insertion of the left and right side punches and the volume for the retraction of the ring 252 are equal. Here, the left and right passages 131 and 132 are further formed, and the lower passage 133 is formed. Thus, the left and right side punches 226 and 227 and the ring 252 sliding in a direction different from the sliding direction of these side punches.
This enables forging of a complicated shape having openings in three directions.

Next, as shown in FIG. 85, the left and right side punches 226 and 227 are retracted. Then, as shown in FIG. 86, the ring 252 is raised to
Discharge 0B. Finally, the remaining wall is cut to obtain a final molded product.

In the die forging method according to the twelfth embodiment, the left and right side punches 226 and 223 are inserted into the forging material while the ring 252 (die spin) is retreated under a back pressure by applying to one end surface of the forging material. 227 (punch), and a hole forming step of forming a hole by punching the left and right side punches 226 and 227 (punch).
(Die spin) is driven from a direction other than the retreat direction or the reverse direction. Thus, the ring 252
Since the left and right side punches 226 and 227 (punches) are driven from directions other than the retreat direction (die spin) or the reverse direction, products of complex and various shapes such as cheese can be formed.

Further, according to this embodiment, the left and right side punches 226 and 227 (a plurality of punches) are simultaneously driven from different directions to perform the forming, and the ring 252 (die spin) is retracted while applying a back pressure during forging. ing. For this reason, products of complicated and various shapes can be formed.

Next, a thirteenth embodiment will be described. FIG. 87 is a side sectional view showing the structure of a multi-header formed by the die forging method according to the thirteenth embodiment of the present invention.
The multi-header 140 of this example has a passage 1 penetrating left and right.
41 and 3 which are arranged at right angles to this passage and communicate with the passage
It has two vertical passages 142.

FIGS. 88 to 90 are cross-sectional views schematically showing an apparatus for forging the multi-header of FIG. 87 and a forging process. This brass material forging device has a lower die and an upper die corresponding to the lower die. The lower die has a lower die 12, a left side punch 226, a right side punch 227 and a right hollow pin 255. Left side punch 226 is lower die 12
Slide through the pin insertion hole. The right hollow pin 227 slides through the insertion hole of the lower die 12. The right side punch 227 slides inside the right hollow pin 255. Further, three fixed punches 253 are provided in the lower die 12 in a direction perpendicular to the insertion hole.
, And a lower hollow die pin 252 that slides up and down on the outer periphery of the fixed punch 253.

Next, the forging process will be described. First, with the mold opened, the forging material 140A is set on the lower die 12 at a position left of the leftmost hollow die spin 252a. At this time, the tips of the right side punch 227 and the right hollow pin 255 are on the same plane, and both tips are located to the left of the leftmost hollow die pin 252a. Next, the upper die 19 is lowered, and the lower surface of the upper die 19 is brought into contact with the upper surface of the lower die to clamp the die. Next, as shown in FIG. 88, the left side punch 226 is inserted rightward. At the same time, the right hollow pin 255 is retracted until the vicinity of the leftmost fixed punch 253a is exposed. Further, the leftmost lower hollow die spin 252a is lowered. At this time, the forged material flows and deforms, and a part of the left and right passages and a part of the leftmost upper and lower passages are formed.

Subsequently, as shown in FIG. 89, when the left side punch 226 is further inserted, the leftmost lower hollow die pin 252a descends to the locking surface. Here, the first vertical passage is formed. At this time, the right side punch 22
7 is fixed. Next, as shown in FIG. 90, the left side punch 227 is further inserted rightward. at the same time,
The right hollow pin 255 is retracted so that the periphery of the second fixed punch 253b is exposed. Further, the lower hollow die spin 252b is lowered. At this time, the first lower hollow die pin 252a is locked and fixed. The forged material flows and deforms, and a part of the second vertical passage is formed.
Further, the left side punch 227 is inserted, the lower hollow die pin 252b is lowered to the locking surface, and a second vertical passage is formed. Thus, by providing the plurality of fixed punches 253 on different axes, forging of a complicated shape can be performed.

This operation is repeated by the number of upper and lower passages to form a plurality of upper and lower passages. The final molded product is
A wall remains at one end of the left and right passages and between the left and right passages and the up and down passages. Therefore, these walls are cut to obtain a final molded product.

In the die forging method according to the thirteenth embodiment, the hollow die spin 252 (die spin) is applied to one end surface of the forging material and backed down while applying back pressure.
The method includes a step of driving a left side punch 227 (punch) into the forging material or pressing a die to forging, and a plurality of hollow die pins 252 (die pins) are provided to form a plurality of deep holes. Therefore, a product having a complicated shape having a large number of holes such as a multi-header can be formed.

[0179]

As is apparent from the above description, according to the present invention, it is possible to provide a die forging method having features such as high productivity and high molding accuracy.

[Brief description of the drawings]

FIG. 1 is a view schematically showing a structure of a brass flush fitting formed by a die forging method according to one embodiment of the present invention, FIG. 1 (A) is a plan view, and FIG. 1 (B) is a side sectional view. Figure, Figure 1
(C) is a perspective view.

FIG. 2 is a cross-sectional view schematically showing an apparatus for forging the spout tip metal fitting of FIG. 1 and a forging process.

FIG. 3 is a cross-sectional view schematically showing an apparatus for forging the spout tip metal fitting of FIG. 1 and a forging step.

FIG. 4 is a sectional view schematically showing an apparatus for forging the spout tip metal fitting of FIG. 1 and a forging step.

FIG. 5 is a diagram schematically showing a configuration of a hydraulic control system of the brass material forging device shown in FIGS. 2, 3 and 4.

6 is an enlarged sectional view showing details of a lower die 11, an upper die 17, and a forging material 3A shown in FIGS. 2 to 4; FIG.

FIG. 7 is an enlarged sectional view showing details of a lower die 11, an upper die 17, and a forging material 3A shown in FIGS. 2 to 4;

FIG. 8 is an enlarged sectional view showing details of a lower die 11, an upper die 17, and a forging material 3A shown in FIGS. 2 to 4;

9 is an enlarged sectional view showing details of a lower die 11, an upper die 17, and a forging material 3A shown in FIGS. 2 to 4; FIG.

FIG. 10 is a stroke diagram of a die and a punch at the time of forging.

FIG. 11 is a sectional view showing a structure of a pedestal formed by a die forging method according to a second embodiment of the present invention.

FIG. 12 is a sectional view showing an intermediate forged product of the pedestal of FIG. 11;

13 is a cross-sectional view schematically illustrating an apparatus for forging the pedestal intermediate forged product of FIG. 12 and a forging process.

14 is a sectional view schematically showing an apparatus for forging the pedestal intermediate forged product of FIG. 12 and a forging process.

15 is a cross-sectional view schematically showing an apparatus for forging the pedestal intermediate forged product of FIG. 12 and a forging process.

FIG. 16 is a sectional view schematically showing an apparatus for forging the pedestal intermediate forged product of FIG. 12 and a forging step.

17 is a cross-sectional view schematically showing an apparatus for forging the pedestal intermediate forged product of FIG. 12 and a forging process.

FIG. 18 is a view showing the structure of an impeller according to a third embodiment of the present invention, wherein FIG. 18 (A) is a plan view and FIG. 18 (B) is a sectional view.

19 is a view showing the structure of an intermediate forged product of the impeller of FIG. 18, wherein FIG. 19 (A) is a plan view and FIG. 19 (B) is a sectional view.

20 is a cross-sectional view schematically illustrating an apparatus for forging the impeller intermediate forged product of FIG. 19 and a forging process.

21 is a sectional view schematically showing an apparatus for forging the impeller intermediate forged product of FIG. 19 and a forging process.

FIG. 22 is a cross-sectional view schematically illustrating an apparatus for forging the impeller intermediate forged product of FIG. 19 and a forging process.

23 is a cross-sectional view schematically showing an apparatus for forging the impeller intermediate forged product of FIG. 19 and a forging process.

24 is a cross-sectional view schematically showing an apparatus for forging the impeller intermediate forged product of FIG. 19 and a forging process.

25 is a cross-sectional view schematically showing an apparatus for forging the impeller intermediate forged product of FIG. 19 and a forging process.

26 is a cross-sectional view schematically illustrating an apparatus for forging the impeller intermediate forged product of FIG. 19 and a forging process.

FIG. 27 is a cross-sectional view schematically showing an apparatus and a forging process according to another embodiment for forging the impeller intermediate forged product of FIG.

FIG. 28 is a cross-sectional view schematically showing an apparatus and a forging process according to another embodiment for forging the impeller intermediate forged product of FIG.

FIG. 29 is a cross-sectional view schematically showing an apparatus for forging the impeller intermediate forged product of FIG. 19 and a forging process according to another embodiment.

FIG. 30 is a cross-sectional view schematically showing an apparatus for forging the impeller intermediate forged product of FIG. 19 and a forging process according to another embodiment.

FIG. 31 is a cross-sectional view schematically showing an apparatus for forging the impeller intermediate forged product of FIG. 19 and a forging process according to another embodiment.

FIG. 32 is a cross-sectional view schematically showing an apparatus for forging the impeller intermediate forged product of FIG. 19 and a forging process according to another embodiment.

FIG. 33 is a cross-sectional view schematically showing an apparatus for forging the impeller intermediate forged product of FIG. 19 and a forging process according to another embodiment.

FIG. 34 is a cross-sectional view schematically showing an apparatus for forging the impeller intermediate forged product of FIG. 19 and a forging process according to another embodiment.

FIG. 35 is a cross-sectional view schematically showing an apparatus for forging the impeller intermediate forged product of FIG. 19 and a forging process according to another embodiment.

FIG. 36 is a cross-sectional view schematically showing an apparatus and a forging process according to another embodiment for forging the impeller intermediate forged product of FIG.

FIG. 37 is a cross-sectional view schematically showing an apparatus for forging the impeller intermediate forged product of FIG. 19 and a forging process according to another embodiment.

FIG. 38 is a view showing a structure of a water meter formed by a die forging method according to a sixth embodiment of the present invention, and FIG.
(A) is a front sectional view, and FIG. 38 (B) is a partial sectional plan view.

39 is a view showing a structure of an intermediate forged product of the water meter of FIG. 38, FIG. 39 (A) is a front sectional view, and FIG. 39 (B).
Is a partial cross-sectional plan view.

40 is a view schematically showing an apparatus for forging the water meter intermediate forged product of FIG. 39 and a forging step.

41 is a diagram schematically showing an apparatus for forging the water meter intermediate forged product of FIG. 39 and a forging process.

42 is a diagram schematically showing an apparatus for forging the water meter intermediate forged product of FIG. 39 and a forging process.

FIG. 43 is a view schematically showing an apparatus for forging the water meter intermediate forged product of FIG. 39 and a forging step.

44 is a diagram schematically showing an apparatus for forging the water meter intermediate forged product of FIG. 39 and a forging process.

45 is a view schematically showing an apparatus for forging the water meter intermediate forged product of FIG. 39 and a forging step.

FIG. 46 is a view schematically showing an apparatus for forging the water meter intermediate forged product of FIG. 39 and a forging step.

FIG. 47 is a view schematically showing an apparatus for forging the water meter intermediate forged product of FIG. 39 and a forging step.

48 is a view schematically showing an apparatus for forging the water meter intermediate forged product of FIG. 39 and a forging step.

FIG. 49 is a view showing an SCC resistance test apparatus.

FIG. 50 is a view showing an eco-erosion resistance test apparatus.

FIG. 51 is a graph showing the results of an eco-resistance test.

FIG. 52 (A) is a perspective view, and FIG. 52 (B) is a cross-sectional view, showing a structure of a disposal shaft formed by the die forging method according to the seventh embodiment of the present invention.

53 is a view showing the structure of an intermediate forged product of the throwaway shaft of FIG. 52, FIG. 53 (A) is a perspective view, and FIG. 53 (B) is a sectional view.

FIG. 54 is a cross-sectional view schematically showing an apparatus for forging the intermediate shaft forged product of FIG. 53 and a forging step.

FIG. 55 is a cross-sectional view schematically showing an apparatus for forging a discarded shaft intermediate forged product of FIG. 53 and a forging step.

FIG. 56 is a cross-sectional view schematically showing an apparatus and a forging step for forging the discarded shaft intermediate forged product of FIG. 53.

FIG. 57 is a view showing a structure of a throw-away shaft formed by a die forging method according to an eighth embodiment of the present invention, wherein FIG. 57 (A) is a perspective view and FIG. 57 (B) is a cross-sectional view.

58 is a view showing the structure of an intermediate forged product of the throwaway shaft of FIG. 57, FIG. 58 (A) is a perspective view, and FIG. 58 (B) is a sectional view.

FIG. 59 is a cross-sectional view schematically showing an apparatus for forging the discarded shaft intermediate forged product of FIG. 58 and a forging step.

60 is a cross-sectional view schematically showing an apparatus for forging the discarded shaft intermediate forged product of FIG. 58 and a forging step.

61 is a cross-sectional view schematically showing an apparatus for forging the discarded shaft intermediate forged product of FIG. 58 and a forging step.

62 is a cross-sectional view schematically showing an apparatus for forging the forged shaft intermediate forged product of FIG. 58 and a forging step.

63A and 63B are diagrams showing a structure of a hand shower support fitting formed by a die forging method according to a ninth embodiment of the present invention, wherein FIG. 63A is a plan sectional view, and FIG. It is.

FIG. 64 is a sectional view schematically showing an apparatus for forging the hand shower support of FIG. 63 and a forging step.

FIG. 65 is a cross-sectional view schematically showing an apparatus for forging the hand shower support of FIG. 63 and a forging step.

FIG. 66 is a cross-sectional view schematically showing an apparatus for forging the hand shower support of FIG. 63 and a forging step.

67 is a sectional view schematically showing an apparatus for forging the hand shower support of FIG. 63 and a forging step.

FIG. 68 is a cross-sectional view schematically showing an apparatus for forging the hand shower support of FIG. 63 and a forging step.

FIG. 69 is a cross-sectional view schematically showing an apparatus for forging the hand shower support of FIG. 63 and a forging step.

FIG. 70 is a side sectional view showing a structure of a flash valve lid formed by a die forging method according to a tenth embodiment of the present invention.

FIG. 71 is a cross-sectional view schematically showing an apparatus for forging the hand shower support of FIG. 70 and a forging step.

72 is a sectional view schematically showing an apparatus for forging the hand shower support of FIG. 70 and a forging step.

73 is a sectional view schematically showing an apparatus for forging the hand shower support of FIG. 70 and a forging step.

74 is a sectional view schematically showing an apparatus for forging the hand shower support of FIG. 70 and a forging step.

75 is a sectional view schematically showing an apparatus for forging the hand shower support of FIG. 70 and a forging step.

76 is a sectional view schematically showing an apparatus for forging the hand shower support of FIG. 70 and a forging step.

FIG. 77 is a cross-sectional view schematically showing an apparatus for forging the hand shower support of FIG. 70 and a forging step.

FIG. 78 is a side sectional view showing a structure of an H bush formed by a die forging method according to an eleventh embodiment of the present invention.

FIG. 79 is a cross-sectional view schematically showing an apparatus for forging the H bush of FIG. 78 and a forging step.

FIG. 80 is a cross-sectional view schematically showing an apparatus for forging the H bush of FIG. 78 and a forging step.

FIG. 81 is a side sectional view showing the structure of a cheese formed by the die forging method according to the twelfth embodiment of the present invention.

FIG. 82 is a sectional view schematically showing an apparatus for forging the cheese of FIG. 81 and a forging step.

FIG. 83 is a cross-sectional view schematically showing an apparatus for forging the cheese of FIG. 81 and a forging step.

FIG. 84 is a cross-sectional view schematically showing an apparatus for forging the cheese of FIG. 81 and a forging step.

FIG. 85 is a cross-sectional view schematically showing an apparatus for forging the cheese of FIG. 81 and a forging step.

86 is a sectional view schematically showing an apparatus for forging the cheese of FIG. 81 and a forging step.

FIG. 87 is a side sectional view showing a structure of a multi-header formed by a die forging method according to a thirteenth embodiment of the present invention.

FIG. 88 is a cross-sectional view schematically showing an apparatus for forging the multi-header of FIG. 87 and a forging step.

FIG. 89 is a cross-sectional view schematically showing an apparatus for forging the multi-header of FIG. 87 and a forging step.

90 is a sectional view schematically showing an apparatus for forging the multi-header of FIG. 87 and a forging step.

[Explanation of symbols]

Reference Signs List 3 spout tip fitting 4 fitting part 6 step fitting part 7 uneven part 10 forging device for brass material 11 lower die 12 lower die 13 die spin 14 first cylinder 15 ejector pin 16 stepped forming hole 17 upper die 18 upper slide 19 Upper die 20 Upper outer punch 21 Lower inner punch 22 Main cylinder 23 Second cylinder 24 Concave hole 25 Lock plate 26 Spring receiving hole 27 Compression spring 28 Insertion hole 29 Flange forming part 30 Fitting part forming part 31 Inner punch insertion hole 41 Hydraulic pressure supply device 42, 43, 44 Electromagnetic directional switching valve 45, 46 Electromagnetic proportional relief valve 47 Detection switch 48 Control unit 50 Pedestal 60 Impeller 70 Water meter 80, 90 Discard shaft 100 Hand shower support bracket 110 Flash valve lid 120 H Bush 130 Cheese 14 Multi Header 224 upper punch 226 left side punches 227 right side punches 228 in the punch 229 heat insulator 230 SUS
Plate 231 Glass desiccator 232 Sample 233 Orifice 234 Resin stopper 235 Lower punch 236 Color 237 Top 238 Lower inner die spin 239 Lower outer die spin 252 Hollow die spin 253 Lower fixed punch 255 Hollow pin

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Ryoichi Sugimoto 2-1-1, Nakajima, Kokurakita-ku, Kitakyushu-city, Fukuoka Prefecture Inside Totoki Kiki Co., Ltd. 1-1-1, Totoki Kiki Co., Ltd. (72) Inventor Yoji Higashi 2-1-1 Nakajima, Kokurakita-ku, Kitakyushu-shi, Fukuoka Tochiki Kiki Co., Ltd. (72) Inventor Jun Yamauchi Kokura, Kitakyushu-shi, Fukuoka 2-1-1 Nakajima, Kita-ku Toto Kiki Co., Ltd. (72) Inventor Kenji Uchio 2-1-1 Nakajima, Kokurakita-ku, Kitakyushu-shi, Fukuoka F-term (in reference) 4E087 AA08 AA10 BA07 CA14 CB02 CB04 EC12 HB03

Claims (29)

[Claims] 1. A die forging method in which a forged material is plastically flowed by being pressed in a forging die to form a predetermined shape; a pre-forging step and a subsequent hole forming step are performed using the same die. In the pre-forging step, at least a part of the forging material is forged so as to fill the cavity of the mold to obtain a shape of a part of the molded product. A die forging method, wherein a hole is formed by punching a punch into the forging material while retracting while applying back pressure against an end face. 2. A die forging method in which a forged material is plastically flowed by being pressed in a forging die to form it into a predetermined shape; a pre-forging step and a subsequent hole forming step are performed using the same die. In the pre-forging step, a part of the shape of the molded product is obtained. A die forging method, wherein a hole is formed by driving, and the die spin is not moved during the pre-forging. 3. A die forging method in which a forged material is plastically flowed by being pressed in a forging die to form it into a predetermined shape; a hole forming step and a post forging step are performed using the same die. In the hole forming step, while punching a punch into the forged material to form a hole while retracting while applying back pressure by applying a die spin to one end surface of the forged material, at least in the post-forging step, A die forging method, wherein a part of the forged material is forged to obtain a shape of a part of a molded product. 4. A die forging method in which a forged material is plastically flowed by being pressed in a forging die to form a predetermined shape; a hole forming step and a forging step before or after using a same die. In the hole forming step, a punch is punched into the forging material to form a hole while the die spin is applied to one end surface of the forged material and retreated under a back pressure, and the die spin is formed in the forging step. A die forging method characterized in that the forging material is basically held so as not to recede against the molding pressure of the forging material. 5. A die forging method in which a forged material is plastically flowed by being pressed in a forging die to form a predetermined shape; a die spin is applied to one end surface of the forged material to apply back pressure. A hole forming step of forming a hole by driving a punch into the forging material while retreating, wherein the punch is driven from a direction other than the retreat direction of the die spin or the reverse direction. . 6. A die forging method in which a forged material is plastically flowed by being pressed in a forging die to form a predetermined shape; a die for forging the outer shape of a molded product from the same direction;
A die forging method characterized by performing forging by pressing a forging material in combination with a punch for forming a concave part of a molded product, and retracting while applying back pressure to a die spin during forging. 7. A die forging method in which a forged material is plastically flowed by being pressed in a forging die to form a predetermined shape; a plurality of punches forming a plurality of recesses from the same direction are formed on the forged material. A die forging method characterized by performing forging by pressing, and backing down while applying back pressure to the die spin during forging. 8. The die forging method according to claim 6, wherein the forming is performed by using the die and the punch at different timings. 9. The die forging method according to claim 7, wherein the forming is performed using the plurality of punches at different timings. 10. A die forging method in which a forged material is plastically flowed by being pressed in a forging die to form a predetermined shape; a plurality of punches are simultaneously driven into the forged material from different directions to perform the forming. In addition, a die forging method characterized in that during forging, the die is retracted while applying the back pressure of the die spin. 11. A die forging method in which a forged material is plastically flowed by being pressed in a forging die to form a predetermined shape; a die spin is applied to one end surface of the forged material to apply back pressure. A die forging method comprising a step of driving a punch or pressing a die into the forging material to forge while retracting, and forming a plurality of holes by providing a plurality of the die spins. 12. The die forging method according to claim 11, wherein the plurality of die spins are sequentially operated with a time lag to sequentially form the plurality of holes. 13. A die forging method in which a forged material is plastically flowed by being pressed in a forging die to form it into a predetermined shape; a method in which a die spin is applied to one end surface of the forged material and pressure is applied; A step of pressing a punch or a die against the forged material to advance the punch or the die to a predetermined position to complete the forging. Wherein the die spin is retracted when the pressure exceeds the predetermined pressure. 14. A die forging method in which a forged material is plastically flowed by being pressed in a forging die to form a predetermined shape; and a die spin is applied to one end surface of the forged material to apply back pressure. A hole forming step of punching a punch into the forged material to form a hole while retracting, forming an uneven portion on an end surface for giving a back pressure of the die spin, and forming a part of the product shape with the uneven portion. A die forging method characterized by the following. 15. A die forging method in which a forged material is plastically fluidized by being pressed in a forging die to form a predetermined shape; an overhanging step of forming an overhang by forging; and further forging the overhang. And a forming step of forming into a predetermined shape, wherein both steps are performed in the same die. 16. A die forging method in which a forged material is plastically flowed by being pressed in a forging die to form it into a predetermined shape; an overhanging step of forming an overhang by forging; and further forging the overhang. And a forming step of forming the sheet into a predetermined shape. 17. A die forging method in which a forged material is plastically flowed by being pressed in a forging die to form a predetermined shape; an overhanging step of forming an overhang by forging; and further forging the overhang. And a forming step of forming the forged material into a predetermined shape by forging the forged material a plurality of times in the overhanging step. 18. A die forging method in which a forged material is plastically flowed by being pressed in a forging die to form a predetermined shape; in parallel with driving a first punch into the forged material, the method comprises: A die forging method, wherein a forging material is processed by a second punch or a die without retreating the first punch. 19. A die forging method in which a forging material is plastically flowed by being pressed in a forging die to form a predetermined shape; a first method for defining a cavity on one side of the forging material. Step, pressing the forging material from the other end side of the forging material, extends the one end of the forging material and fills the cavity to form an outer shape of the same, thereby obtaining an overhanging body. A second step, and after the second step, a third step of driving a punch in the axial direction into the overhang body from the one end face to form a recess in the overhang body. And die forging method. 20. A die forging method in which a forging material is plastically flowed by being pressed in a forging die to form a predetermined shape; and a forging material is axially inserted into the forging material from an end face of one end of the forging material. A step of forming a concave portion by driving a punch, and thereafter, forming a second concave portion having a larger diameter and shallower than the concave portion on the end face by using a second punch disposed on an outer peripheral portion of the punch. A die forging method, further comprising the step of: the step (A), wherein the die spin contacting the other end of the forging material is retracted while applying back pressure. 21. A die forging method in which a forged material is plastically flowed by being pressed in a forging die to form a molded product having a convex portion with an undercut; A first step of projecting the original part of the part, and after the first step, a second step of crushing the original part from a direction opposite to the direction in which the part is projected and projecting the projection to the side; A die forging method, comprising: 22. A die forging method in which a forged material is plastically flowed by being pressed in a forging die to form a molded product having a top cylindrical shape, the cylindrical portion being formed by a die cavity. A step of pushing a punch into the center of the forged material and extruding backward while applying a back pressure to the end of the cylinder while molding on the surface, and used for molding the cylinder when removing the molded product A die forging method comprising: a B step of first punching out the punch; and a C step of extracting the molded product from a die used to mold the outer peripheral surface of the cylindrical portion after the B step. . 23. The die forging method according to any one of claims 1 to 23, wherein the molded product after forging and cooling is made of a brass material having the following crystal structure: (a) α + β phase and The area ratio of the β phase is 15% or more, (b) the average crystal grain size of the α phase and the β phase is 15 μm or less, and (c) the Sn concentration in the β phase is 1.5% by weight or more. 24. The mold forging method according to any one of claims 1 to 23, wherein the molded product after forging and cooling is made of a brass material having the following crystal structure: (a) α + γ phase and (b) the average crystal grain size of the α phase is 15 μm or less, the average crystal grain size of the short axis of the γ phase is 8 μm or less, and (c) the γ phase The Sn concentration is at least 8 wt%, and (d) the γ phase is scattered at the grain boundaries of the α phase. 25. The die forging method according to any one of claims 1 to 23, wherein the molded product after forging and cooling is made of a brass material having the following crystal structure: (a) α + β + γ phase; α-phase area ratio is 40 to 94
%, The area ratio of the β phase and the α phase is 3 to 30%, respectively; (b) the average crystal grain size of the α phase and the β phase is 15 μm or less;
The average crystal grain size of the minor axis of the phase is 8 μm or less, (c) the Sn concentration in the γ phase is 8 wt% or more, and (d) the γ phase surrounds the α phase. 26. The method according to claim 1, wherein the forging material is a brass material, and the method includes a step of heating the forging material and the forging die to 300 to 550 ° C. for forging. Die forging method. 27. The brass material has an apparent Zn content of 37 to 50 wt% and an Sn content of 0.5 to 7 wt%, and has an average crystal grain diameter of a short axis in a crystal structure in the temperature range. Has a γ phase of 15 μm or less. 28. The brass material according to claim 1, wherein the brass material has a temperature range of 300 to 550 ° C. and a molded product after forging and cooling is made of a brass material having the following crystal structure. Die forging method. (1) It has any crystal structure of α + β phase, α + γ phase or α + β + γ phase. (2) The area ratio of α phase is 44 to 80%, the area ratio of β phase is 0 to 55%, and γ phase. (3) The average particle size of the α phase, β phase and γ phase is 15 μm or less, and (4) the α phase and γ phase are dispersed. 29. The die forging method according to claim 1, wherein the γ phase precipitates in the β phase when the brass material is heated to a temperature for forging.