JPH0528534U - Mold for die forging - Google Patents

Abstract

(57) [Summary] [Purpose] In a die for die for which a knockout pin is attached, the load applied to the knockout pin during die forging is not carried by an intermediate die or the like unlike the prior art, but the metal die is used. The mold body is directly and distributively distributed in the load direction to be carried to improve the service life of the mold and to simplify the mold structure by eliminating the need for an intermediate mold or the like. [Constitution] Knockout pin (3) to be attached to the mold (2)
Is a rod-shaped base rod part (3a) and a disc shape with a diameter larger than this base rod part (3a), and its end face is an impression of the mold (2).
(2) Formed in a shape that forms part of the back side of the mold
The pressure receiving head (3a) formed on the pressure receiving surface that abuts (2), and the load applied during die forging is applied to the mold (2) through the pressure receiving head (3a). ) Directly support the main unit. In addition, the knockout pin (3) that becomes the pressure receiving surface
The back surface of the pressure receiving head (3a) is formed into an inclined surface having an inclination angle α of 5 degrees to 35 degrees.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a die for die forging, and particularly to a die having knockout pins for taking out a product, such as a die for press die forging.

[0002]

[Prior Art]

 A die used for press die forging or the like is usually equipped with a knockout pin for taking out a product. In addition, since the knockout pins attached to these molds are operated by a driving means (a knocking mechanism normally provided in a forging device such as a press) arranged outside the molds when the product is taken out, the molds concerned Is formed so as to penetrate between the impression and the outside, and the inner end surface thereof forms a part of the impression and also carries a part of the load applied during die forging.

However, when the load applied to the knockout pin is directly transmitted to and carried by the knocking mechanism or the like, it is necessary to strengthen the device structure of the knocking mechanism or the like, and it is necessary to increase the size of the forging device to be used. In order to avoid this, conventionally, as shown in [Fig. 2], the load applied to the knockout pin is carried by a shank or an intermediate die arranged in series with the die. The configuration is the most commonly adopted.

FIG. 2 is a cross-sectional view showing a typical example of a conventional die forging die. In the mold shown in the figure, at the lower end of the main rod part (23a) of the knockout pin (23) mounted on the lower die (22), the pressure receiving part (23b) having a diameter larger than that of the main rod part (23a) is provided. ) Is provided, and the load applied during die forging is carried by the intermediate die (24) connected to the lower die (22) via the pressure receiving portion (23b).

2A shows a state in which the material to be molded M is pressure-molded under the pressure of the upper die (21). At this time, the knockout pin (23) is The applied load is entirely carried by the intermediate mold (24) via the pressure receiving portion (23b) and is not transmitted to the knocking bar (25) for operating the knockout pin (23). Further, Fig. (B) shows a state in which the press-molded material M is taken out. At this time, the knockout pin (23) is lifted by the operation of the knocking bar (25), The material M is pushed out from the impression (22a) of the lower mold (22).

[0006]

[Problems to be solved by the device]

 However, in the above-mentioned conventional mold, the working space for vertically moving the expanded pressure receiving part (23b) of the knockout pin (23) between the lower mold (22) and the intermediate mold (24). It is indispensable to provide S 2, and this causes various problems.

That is, the lower mold (22) for mounting the knockout pin (23) has a double structure with the intermediate mold (24), and since the working space S is provided in the middle, the structure is As it becomes complicated, the die strength decreases.

Moreover, when the impression (22a) of the lower die (22) is provided deeply, the stroke for pushing out the material M to be molded from within the impression (22a) becomes large, and the pressure receiving portion of the knockout pin (23) Since it is necessary to increase the height of the working space S for moving the (23b) up and down, not only the thickness of the lower die (22) required for design strength but also the intermediate die (24 ) Is also forced to be thicker. As a result, the total height of the two must be increased, which causes problems not only in terms of cost but also in securing the installation space.

On the other hand, the load applied to the knockout pin (23) is proportional to the area of the upper end surface of the main rod portion (23a) forming a part of the impression (22a) of the lower die (22). The size of the pressure receiving portion (23b) that transmits the load to the intermediate die (24) is set in proportion to the diameter of the main rod portion (23a). Therefore, in order to reduce the cross-sectional area of the working space S, it suffices to reduce the diameter of the main rod portion (23a) of the knockout pin (23), but as described above, it is necessary to push out the material M to be molded. When the stroke is large, if the diameter of the main rod portion (23a) is reduced, bending or buckling is likely to occur due to the load applied during die forging, making it impossible to take out the molded material M during operation, and There is a risk of disrupting the operation at times.

Further, the upper limit of the knockout pin (23) is restricted by the height of the working space S. Therefore, unless the height of the working space S has a margin in advance, it is changed midway for the convenience of handling or the like. There is also the inconvenience of not being able to respond even if you want to.

The present invention has been made to solve the above-mentioned problems of the prior art, and the load applied to the knockout pin at the time of die forging can be directly carried by the die body, and the intermediate metal It is easy to adjust the extrusion amount of the material to be molded from within the impression by eliminating the need for auxiliary members such as molds and special working space, and for improving die life. The purpose is to provide the mold.

[0012]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention has the following configuration. That is, the die forging die according to the present invention is a die forging die that is equipped with a knockout pin for taking out a product, and has a rod-shaped base rod portion and a diameter larger than the base rod portion. Now, a knockout pin whose end surface is formed into a shape that forms a part of the impression of the mold and whose back side is a pressure receiving head formed on the pressure receiving surface that abuts against the mold It is characterized by being mounted in a fitting hole provided in a shape corresponding to the knockout pin.

In the die forging die according to the invention of claim 2, the pressure receiving surface of the pressure receiving head of the knockout pin is inclined so as to continuously project from the outer peripheral end toward the center toward the opposite end face. It is formed on a slope and has an inclination angle of 5 to 35 degrees.

[0014]

[Action]

 In the mold of the present invention, a rod-shaped base rod portion and a diameter larger than that of the base rod portion are formed, and the end face is formed into a shape forming a part of the impression of the mold, and the back side is pressed against the mold. Since the knockout pin having the pressure receiving head formed on the pressure receiving surface in contact with the knockout pin is attached to the insertion hole formed in the shape corresponding to the knockout pin, the load applied to the knockout pin during die forging is It can be directly carried by the mold body via the pressure receiving head, and it is not necessary to provide an intermediate mold for carrying this load in series with the mold, unlike the conventional mold. .. In addition, since there is no particular restriction on the amount of movement of the mold toward the inside of the impression, by appropriately adjusting the knocking amount from the end of the base rod part, the amount of movement from within the impression of the material to be molded can be improved. The amount of extrusion can be changed and adjusted easily.

Further, in the die of claim 2, the pressure receiving surface of the pressure receiving head of the knockout pin is continuously inclined from the outer peripheral end portion toward the central portion so as to protrude in the direction opposite to the end face, and the inclination angle thereof is also increased. Since it is formed on the inclined surface with a degree of 5 to 35 degrees, the load applied to the knockout pin during die forging is appropriately dispersed not only in one vertical direction but also as a component force through the inclined surface in the outer peripheral direction. It can be supported on the mold body, which can prevent the stress concentration portion from being formed on the mold body, and can improve its service life. Here, the reason why the inclination angle is limited to the range of 5 degrees to 35 degrees is that if the inclination angle is less than 5 degrees, the component force in the outer peripheral direction is small and the load cannot be effectively dispersed. On the other hand, if the inclination angle exceeds 35 degrees, the component force in the outer peripheral direction becomes too large, that is, the pressure receiving head of the knockout pin acts as if it were a wedge, and rather reduces the service life of the mold. is there.

[0016]

【Example】

 An embodiment of a die for die forging according to the present invention will be described below with reference to the drawings.

[FIG. 1] is a cross-sectional view showing a mold of one embodiment of the present invention, wherein (a) is a cross-sectional view showing a state during pressure molding, and (b) is (a). (A) is an enlarged cross-sectional view of the portion a, and (c) is a cross-sectional view showing a state of taking out the material to be molded.

In (a) of FIG. 1, (1) is an upper mold, (2) is a lower mold, and these upper and lower molds (1), (2) The impressions (1a) and (2a) are provided, and they are arranged in the pressing portion of a forging device (not shown). In addition, the lower mold (2) has an annular pressure-increasing expanded portion (4a) at the upper end of the base rod hole (4b) that vertically penetrates between the impression (2a) and the lower surface. There is a pin insertion hole (4) formed with.

Reference numeral (3) is a knockout pin, and the knockout pin (3) is a rod-shaped base rod portion (3a) and a pressure receiving member formed in a disk shape having a diameter larger than that of the base rod portion (3a). It has a head part (3b) and is vertically movably inserted into the pin insertion hole (4) of the lower mold (2). Also, the pressure receiving head (3b) of the knockout pin (3) is formed such that the upper end surface thereof forms a part of the impression (2a) of the lower mold (2), and the back side surface is the lower mold. It is formed on the pressure receiving surface that contacts the inner surface of the expanded diameter receiving part (4a) of the pin insertion hole (4) provided in (2) and transmits the load applied during die forging to the lower die (2). ing.

Here, the back surface of the pressure receiving head (3b) of the knockout pin (3), which is the pressure receiving surface, continuously protrudes downward from the outer peripheral end toward the center as shown in FIG. The pressure receiving head (3b) is formed with an inclined surface having an inclination angle α, and a corner R of the pressure receiving head (3b) is provided with a corner R having a radius r described later. On the other hand, even at the same inclination angle α as the pressure receiving head (3b) of the knockout pin (3), the inner bottom surface of the pressure receiving expanded portion (4a) of the pin insertion hole (4) into which the knockout pin (3) is inserted. Is formed on the inclined surface, and a corner R of the same radius r is also attached to the corner portion of the outer peripheral lower end of the pressure-increasing expanded portion (4a).

(5) is a knocking bar, and this knocking bar (5) is an output end of a knocking mechanism included in a forging device (not shown), It moves back and forth in the pin insertion hole (4), and its action moves the knockout pin (3) up and down.

In die forging using the die of the present embodiment having the above-mentioned configuration, as shown in (a) of FIG. 1, the material M is pressure-formed by pressing down the upper die (1). However, the load applied to the knockout pin (3) during the pressure forming is transmitted to the lower mold (2) via the pressure receiving head (3b) of the knockout pin (3), All of them are carried by the main body of the lower mold (2).

Therefore, it is not necessary to apply a load at the time of press molding to the base rod portion (3a) of the knockout pin (3), and the knocking bar (5) for operating the knockout pin (3) is not required. ) Can also be prevented from being subjected to the load. Further, when taking out the pressure-formed molded material M, as shown in (c), the knockout pin (3) is lifted by the operation of the knocking bar (5) to move the molded material M to the lower metal. It can be extruded at any height from inside the impression (2a) of the mold (2).

As described above, in the die of this embodiment, the load applied to the knockout pin (3) during die forging is applied to the inner bottom surface of the pressure-increasing expanded portion (4a) of the lower die (2). Although the pressure is to be received, the inner bottom surface of the pressure-increasing expanded portion (4a) is an annular surface having a base rod hole (4b) that does not carry a load in the center. Therefore, when the annular inner bottom surface of the pressure-increasing expanded portion (4a) is simply formed as a flat surface to receive the load in only one vertical direction, a large stress is applied to the lower side of the annular inner bottom surface. And mold material is flowed in the direction of the base rod hole (4b) in the center and deforms, making the knockout pin (3) immovable up and down, and further, the expanded pressure-receiving part that becomes the stress concentration part. There are cases where cracks and fractures originating from the corner portion at the lower end of the outer periphery of (4a) occur and the service life of the die is reduced.

Therefore, in the mold of the present embodiment, the back surface of the pressure receiving head (3b) of the knockout pin (3), which is the suppression pressure receiving surface, and the expanded pressure receiving portion (4a) of the pin insertion hole (4). The bottom surface and the inclined surface are formed, and the load applied to the knockout pin (3) at the time of die forging is not limited to the vertical 1 direction as shown by the arrow in the figure (c) The lower die (2) is supported by the main body of the lower die (2) while being dispersed in the same direction, while the corners of the pressure-increasing expanded portion (4a) are provided with corners R to relieve stress concentration. We aimed to improve strength and service life. From this point of view, the following trial example is conducted to find out the inclination angle α of the inclined surface and the radius r of the corner R that are most suitable for improving the strength and service life of the mold. It was

Regarding a die having a lower die (2) having a sectional shape shown in FIG. 1 and having a diameter of about 300 mm and a height of about 150 mm, the lower die (2) has a pin fitting hole (4 ) Of the pressure-increasing expanded portion (4a), the inclination angle α of the bottom surface is set to 0 °, 5 °, 15 °, 25 °, 35 °, 45 ° and 60 °. A total of 9 types of corner R with radius r of 2.0 mm, 2.5 mm and 4.0 mm were manufactured. Then, using these dies, die forging under the same conditions was repeated, and the fracture lives of each were compared and evaluated.

The breaking life of these dies is determined as the breaking life at the time when a crack occurs at the corner of each pressure-increasing expanded portion (4a), and the fracture life of each die The inclination life angle α of the bottom surface was 0 °, and the breaking life of the mold with the radius r of the pressure-increasing diameter-increasing portion (4a) corner R being 2.5 mm was set to 1 and compared and evaluated. The results are shown in [Table 1].

[0028]

[Table 1]

As shown in [Table 1], the inclination angle α of the inner bottom surface of the pressure-increasing expanded portion (4a) is set to 5 ° to 35 °, preferably 15 ° to 25 °, based on the investigation results of these trial examples. On the other hand, when the radius r of the pressure-increasing expanded portion (4a) corner R is set to 2.5 mm or more, preferably about 3 to 4 mm, it can be understood that the desired improvement of the service life of the die can be achieved. Based on this, in the mold of this embodiment, the inclination angle α is set to 25 degrees selected from the range of 5 degrees to 35 degrees, and the radius r of the corner R is set to 3.0 mm.

As described above, in the die of the present embodiment, the load applied to the knockout pin during die forging is not limited to the vertical 1 direction, but is appropriately adjusted not only in the vertical direction but also in the outer peripheral direction as a component force through the inclined surface. The particles were dispersed and supported on the mold body, which prevented formation of stress concentration parts in the mold body and improved their service life. Moreover, since the load is not applied to the base rod portion (3a) of the knockout pin (3), the base rod portion (3a) has a strength required for taking out the originally intended material regardless of the stroke. The base rod hole (4b) of the pin insertion hole (4) corresponding to the base rod (3a) can be made small to improve the structural strength of the mold body. I was able to raise it. In addition, since it is not necessary to provide an intermediate die or a special working space unlike the conventional die described above, the structure can be greatly simplified.

Further, in the mold of the present embodiment, since no special restriction is imposed on the amount of rise of the knockout pin (3), even if the knocking bar (5) needs to be changed midway due to handling or other reasons. The amount of extrusion of the material to be molded M from the lower die (2) from the impression (2a) can be easily changed and adjusted by adjusting the operation amount of (1). Furthermore, by slightly increasing the area of the upper end surface of the pressure receiving head (3b) of the knockout pin (3), it is possible to support and push up the material M to be molded in a stable state.

[0032]

[Effect of the device]

 As described above, according to the die forging die of the present invention, the load applied to the knockout pin at the time of forging is directly and further dispersed in the load direction, and is carried by the die body. As a result, the service life can be maintained for a long time, and auxiliary structures such as intermediate molds and special operating spaces, which are required in the conventional technology, are not required, and the structure can be greatly simplified. Can be achieved. Furthermore, it is easy to change and adjust the extrusion amount of the material to be molded, and it is possible to enhance the ability to respond to changes in handling conditions in actual operation.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a mold according to one embodiment of the present invention, wherein (a) is a cross-sectional view showing a state during pressure molding, and (b) is a view.
FIG. 3A is an enlarged cross-sectional view of part A in FIG. 1A, and FIG.

FIG. 2 is a cross-sectional view showing a typical example of a conventional die forging die.

[Explanation of symbols]

 (1) --Upper mold (1a)-Impression (2) --Lower mold (2a)-Impression (3) --Knockout pin (3a)-Base rod (3b)-Pressure receiving head Part (4) --Pin insertion hole (4a) --Expansion part for pressure reception (4b) --Base rod hole (5) --Knocking bar M --Molding material

Claims (2)

[Scope of utility model registration request] 1. A die forging die, comprising a knockout pin for taking out a product, wherein a rod-shaped base rod portion has a diameter larger than that of the base rod portion, and an end face is made of an impression of the die. A knockout pin formed in a shape that forms a part and having a pressure receiving head formed on the pressure receiving surface that abuts against the mold is provided with a fitting hole provided in a shape corresponding to this knockout pin. A die for die forging, which is characterized by being attached to the. 2. The pressure-receiving surface of the pressure-receiving head of the knockout pin is formed as an inclined surface which continuously projects from the outer peripheral end toward the center and inclines so as to project in the direction opposite to the end face, and the inclination angle is 5 degrees or more. The die for die forging according to claim 1, wherein the die is 35 degrees.