JP4441721B2 - Forging mold for semi-molten metal and molding method using the mold - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention uses a semi-molten metal forging die and its die that prevent the capture of a solidified layer and the falling of the semi-molten metal when performing mold forging by inserting the semi-molten metal into the mold cavity. Related to the forming method.
[0002]
[Prior art]
In recent years, demands for weight reduction and integration in various machine parts and automobile parts have increased. Furthermore, what is conventionally a forged steel product is shifting to a cast product of light metal. In response to these demands, various attempts have been made to adopt a semi-molten metal forming method.
This semi-molten metal molding is injection-filled into the mold cavity in a semi-molten state where the liquid phase part and the solid phase part coexist. Since the viscosity of the semi-molten metal is high, it is filled in a state close to laminar flow. The Therefore, there is no occurrence of gas defects due to gas entrainment, and the metal structure is uniformly distributed with non-dendritic fine crystal grains and excellent in mechanical strength. (For example, refer to Patent Document 1).
[0003]
[Patent Document 1]
JP-A-8-325652 [0004]
[Problems to be solved by the invention]
However, the following problems occur when a conventional mold for injecting and filling the above-mentioned semi-molten metal into a cavity is used for forging of the semi-molten metal. That is, since the semi-molten metal placed in the cavity portion of the forged lower mold composed of a pair of upper and lower parts has a small amount of latent heat that the semi-molten metal has, the surface layer portion of the semi-molten metal in contact with the lower mold cavity portion is It is cooled rapidly and a so-called solidified layer is easily formed, and such a solidified layer is mixed in the product. When this solidified layer is mixed in the product, there is a problem that the surrounding healthy semi-molten metal portion cannot be completely melted, resulting in defects similar to the hot water boundary. In order to solve this problem, it is conceivable that the semi-molten metal is erected in the lower mold cavity in an elongated state in order to reduce the contact area between the lower part of the semi-molten metal and the lower mold cavity. In this case, the semi-molten metal sometimes tilts before forging with the upper and lower forging dies, and there is a problem that a desired product cannot be obtained because of lack of stability.
[0005]
The present invention has been made in view of the above-mentioned problems, and its purpose is to capture a solidified layer generated when a semi-molten metal is placed in a cavity portion and prevent mixing into a product, The present invention provides a forged die for semi-molten metal, which can stably form a semi-molten metal, and a molding method using the die.
[0006]
[Means for Solving the Problems]
In order to solve the above problems, the first invention in the present invention is to supply a semi-molten metal in a mold cavity in a molten state in which a solid phase and a liquid phase coexist at a temperature immediately above or below the melting point. A forging die for semi-molten metal for performing die forging, wherein the forging die is composed of a pair of detachable dies and a part of one die cavity of the forging die A plate-like recess having a diameter larger than the diameter of the semi-molten metal is placed on the semi-molten metal, and the other of the forging die is moved in the clamping direction to perform die forging. upon, forming excess protrusion of non-product containing solidified layer, a hydraulic Cylinders capturing solidified layer in a semi-molten metal in the dished recess having a diameter larger than the diameter of the semi molten metal, the semi characterized by providing to face the dished recess having a diameter larger than the diameter of the molten metal It is a forging die for the semi-molten metal.
[0007]
In the semi-molten metal forging die, the protrusion for preventing the semi-molten metal from tilting is a circular shape located in a dish-shaped recess having a diameter larger than the diameter of the semi-molten metal. A plurality of cylinders may be provided around the cylinder. Further, according to a second aspect of the present invention, a semi-molten metal in a molten state in which a solid phase and a liquid phase coexist at a temperature immediately above or below the melting point using the forged mold for a semi-molten metal, type, after placing in a dish-shaped recess having a diameter larger than the diameter of the semi molten metal, together with moving the other該鍛Zokin type mold clamping direction performing die forging, of the semi-molten metal A hydraulic cylinder provided so as to face a dish-shaped recess having a diameter larger than the diameter, and forming an excessive protrusion of a non-product including a solidified layer and having a diameter larger than the diameter of the semi-molten metal The solidified layer of semi-molten metal was captured by the recess .
[0008]
DETAILED DESCRIPTION OF THE INVENTION
The semi-molten metal forging die and the molding method using the die according to the present invention will be described in detail below. FIG. 1 is a cross-sectional view of a semi-molten metal forging die having a recess for placing the semi-molten metal slurry of the present invention. FIG. 2 is a cross-sectional view of a semi-molten metal forging die in a clamped state. 3 is an enlarged cross-sectional view of the upper forging die, FIG. 4 is an enlarged cross-sectional view of the lower forging die, FIG. 5 is a front cross-sectional view when a tilt-preventing protrusion is provided in the recess, and FIG. The top view at the time of seeing from is shown.
[0009]
The forged mold 10 for semi-molten metal of the present invention is a dedicated mold for semi-molten metal M, and is mainly composed of an upper mold 12, a lower mold 14, and a piston 41 with a hydraulic cylinder. A mold cavity 20 is formed between 12 and 14. The mold cavity 20 is formed between the upper mold 12 having the convex portion 22 and the lower mold 14 having the concave portion 24.
[0010]
First, the upper mold 12 will be described. As shown in FIG. 1, the upper mold 12 has a convex portion 22, and as shown in FIG. 3, a straight portion 26 and a truncated cone extending from the straight portion 26 toward the tip of the convex portion 22. The tapered portion 28 and the tip end have a flat portion 29.
[0011]
In addition, a space portion 54 is engraved in the upper mold 12. Inside the space portion 54, a base portion 52 to which an extrusion pin 50 for releasing a product from the surface of the upper mold 12 is attached is accommodated vertically. The base 52 is formed by overlapping two bases 52a and 52b.
[0012]
A nut 56 is fixed to the upper end face side of the base 52b, and an extrusion pin 50 having a screw engraved on the end is screwed to the nut 56. The extrusion pin 50 is movable up and down in a sliding hole 58 engraved in the heel direction inside the upper die 12, and after the product is formed, the tip end portion of the extrusion pin 50 extends from the flat portion 29 to the die cavity 20. It is configured to project on the side, and the product taken by the upper mold 12 is released from the upper mold 12.
[0013]
Next, the other lower mold 14 will be described. As shown in FIG. 1, the lower mold 14 has a concave portion 24. As shown in FIG. 4, the concave portion 24 is formed so that it can be inserted into and removed from the convex portion 22 of the upper mold 12. ing. The concave portion 24 is formed on the top of the frustoconical shape when the linear portions 30 forming a small gap between the linear portion 26 and the convex portion 22 of the upper mold 12 and the molds 12 and 14 are combined. In order to forge a product between the die taper portion 28 and the die taper portion 28, a lower die taper portion 32 and a bottom portion 34 are formed.
[0014]
Both the taper portions 28 and 32 have tapered diameters that are different from each other toward the upper portion, and are different in angle between the two, and the preferred angle of the upper tapered portion 28 is 1 degree. It has become. The preferred angle of one lower tapered portion 32 is 1.5 degrees, which is slightly larger than the angle of the upper tapered portion 28. By doing in this way, a product will not be taken by the lower metal mold | die 14 after shaping | molding.
[0015]
Further, the bottom 34 of the lower mold 14 is provided with a dish-like recess 36 that is deeply cut downward from the bottom 34. A side surface of the recess 36 forms a tapered portion 37 whose diameter is increased upward. This taper angle is preferably about 3 to 10 degrees, and if it is 3 degrees or less, the solidified layer generated by cooling between the semi-molten metal M and the bottom 35 of the recess 36 is difficult to be mixed into the product. However, after the molding, when the upper mold 12 is raised, the product is easily taken together with the upper mold 12 without being raised by the lower mold 14.
[0016]
On the other hand, when the temperature is 10 degrees or more, the product is easily lifted together with the upper mold 12 without being taken by the lower mold 14 when the upper mold 12 is lifted after molding. The solidified layer generated by cooling between M and the bottom 35 is easily mixed into the product.
[0017]
A sub-lower die 42 is fitted into a recess-shaped portion on the outer peripheral portion of the lower die 14 located on the back surface of the die cavity 20 to constitute a part of the lower die 14. A space 44 is formed inside the sub-lower mold 42. On the other hand, a circular cylinder 38 connected to the space 44 is opened at the upper center position of the space 44 that forms the main cylinder 46.
[0018]
The circular cylinder 38 is engraved along the direction of the vertical axis so as to open at the bottom 35 located at the center of the recess 36 engraved on the bottom 34 of the lower mold 14. As shown in FIG. 1, a small-diameter vertical piston 40 that moves up and down in the cylinder 38 and a large-diameter horizontal piston 48 that moves up and down in the space 44 are connected to a space portion that spans the space 44 and the cylinder 38. A hydraulic cylinder-equipped piston 41 is provided. Further, when placing the semi-molten metal M in the recess 36 of the lower mold 14, the tip of the saddle type piston 40 faces the mold cavity 20 and is flush with the bottom 35 of the recess 36. ing.
[0019]
In addition, the product formed by die forging between the upper and lower molds 12, 14 is moved to the upper mold 12 when the upper mold 12 is released from the lower mold 14 for product removal. The tip of the saddle type piston 40 protrudes into the mold cavity 20 from the same plane as the bottom 35 of the recess 36 so as to be surely taken up and rise together with the product. The product is reliably released from the lower mold 14 with the support of the saddle type piston 40 by the protruding operation.
[0020]
Hydraulic pipes 60 (a, b) for moving the horizontal piston 48 disposed in the space 44 up and down and controlling the piston 41 with the hydraulic cylinder are disposed.
[0021]
The operation of the semi-molten metal forging die configured as described above will be described.
[0022]
As shown in FIG. 1, the upper and lower molds 12 and 14 are separated from each other. In this state, the hydraulic pipe 60a side is opened, and hydraulic pressure is supplied from the hydraulic pipe 60b side. The tip of the vertical piston 40 that constitutes a part of the cylinder-equipped piston 41 is moved so as to be flush with the bottom 34 of the recess 36.
[0023]
Next, a semi-molten metal M having a frustoconical shape is gripped at the tip of a robot (not shown) so that the large-diameter portion of the semi-molten metal M is positioned at the lower portion, and the concave portion of the lower mold 14 is placed. It is placed on the bottom 34 of 36.
[0024]
Subsequently, the mold clamping device (not shown) is operated to slowly lower the upper mold 14 to perform mold clamping, and the semi-molten metal M is compression-molded and shaped into a desired product. This state is shown in FIG. At this time, the position of the vertical piston 40 is determined according to the supply amount of the semi-molten metal M. Semi-molten metal M of excess to be molded by the mold clamping force is added to the upper mold 12 during compression molding, by pushing down the vertical piston 40 down direction, an excess of the protrusion 62 as shown in FIG. 2 It is formed. This protrusion 21 becomes a non-product part and determines the yield of the molding material.
[0025]
At the time of forging, the cavity pressure (metal pressure) is determined by the projected area of the product (molded product) and the clamping force. Therefore, in the case of a product with a small projected area, the metal pressure may be 5000 kgf / cm 2 or more. is there.
[0026]
When the metal pressure becomes abnormally high in this way, the possibility of blowing burrs from the mold split surface increases. In addition, the sag (life) of the mold is accelerated. Therefore, it is necessary to keep the pressure of the mold cavity 20 at an appropriate value (1000 to 3000 kgf / cm 2). For the reasons described above, the semi-molten metal forging die 10 needs to have a metal pressure adjusting function.
[0027]
By maintaining the hydraulic pressure acting on the vertical piston 40 that constitutes a part of the piston 41 with the hydraulic cylinder in order to absorb the variation in the size of the semi-molten metal M (the variation in the supply amount) by a relief valve or the like. The metal pressure in the mold cavity 20 can be controlled.
[0028]
As described above, the semi-molten metal M formed and solidified at the portion of the recess 36 is not pushed into the mold cavity 20 at the time of molding, but instead becomes an excessive protrusion 62 of a non-product including a solidified layer. For this reason, a solidified layer does not enter. Further, the product taken by the upper mold 12 when the molds 12 and 14 are opened is to grip the excess protrusion 62 first by a robot (not shown), and then lower the push pin 50 to lower the upper mold. The product is released from the upper mold 12 so as to protrude from the flat portion 29 located at the tip of the convex portion of the mold 12.
[0029]
Another embodiment of the present invention will be described with reference to FIGS. FIG. 5 is a front cross-sectional view when the tilt prevention protrusion is provided in the recess, and FIG. 6 is a plan view when viewed from AA in FIG.
[0030]
A sub-lower die 42 is fitted into a concavely engraved portion on the outer peripheral portion of the lower die 14 that becomes the back surface of the die cavity 20 to constitute a part of the lower die 14. A space 44 is formed inside the sub-lower mold 42. On the other hand, a circular cylinder 38 connected to the space 44 is opened at the upper center position of the space 44 that forms the main cylinder 46.
[0031]
This circular cylinder 38 is engraved along the direction of the vertical axis so as to open at the center of a recess 36 engraved in the bottom 34 of the lower mold 14. When the semi-molten metal M is placed in the recess 36 of the lower mold 14, the tip of the saddle type piston 40 faces the mold cavity 20 and is flush with the low part 35.
[0032]
As shown in FIG. 6, four tilt prevention protrusions 64 arranged at equal intervals are fixed to the bottom 34 of the periphery of the circular cylinder 38. The tilt preventing projection 64 has a triangular side surface, and its tip is configured to be lower than the same horizontal position as the bottom 34 of the lower mold 14. In addition, the shape of the protrusion part 64 for tilt prevention does not stick to a triangular shape, but may be, for example, a truncated cone shape.
[0033]
In addition, by disposing the tilt preventing projection 64 on the bottom 34 of the peripheral portion of the cylinder 38, the robot holds the outside of the holding container (also referred to as a cup) containing the semi-molten metal M so that the lower mold 14, the bottom surface side of the semi-molten metal M enters the tilt-preventing projection 64 (FIG. 5), and the semi-molten metal M is not tilted by the anchor effect and is stable. Therefore, the mold is reliably molded by the mold cavity 20 between the upper and lower molds 12 and 14.
[0034]
【The invention's effect】
According to the present invention described above, for the solidified layer trapped in the lower mold, by providing the dished recess having a diameter larger than the diameter of the semi-molten metal, greater than the diameter of the semi-molten metal A hydraulic cylinder provided so as to face a dish-shaped recess having a diameter, forming an excessive protrusion of a non-product including a solidified layer, and a solidified layer with a dish-shaped recess having a diameter larger than the diameter of the semi-molten metal Can be reliably captured, so that the solidified layer is not mixed in the product, and the quality of the product is remarkably improved. In addition, if a plurality of tilt-preventing protrusions are provided in the dish-shaped recess having a diameter larger than that of the semi-molten metal, the semi-molten metal will not tilt before forming, and the solidified layer can be reliably secured. Since the solidified layer is not mixed in the product, the quality of the product and the moldability are remarkably improved.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a semi-molten metal forging die having a recess for placing the semi-molten metal of the present invention.
FIG. 2 is a cross-sectional view of a semi-molten metal forging die in a clamped state.
FIG. 3 is an enlarged sectional view of a forged upper die.
FIG. 4 is an enlarged cross-sectional view of a lower forging die.
FIG. 5 is a front sectional view showing another embodiment of the present invention, in which a tilt preventing projection is provided in the recess.
6 is a plan view when viewed from AA in FIG. 5;
[Explanation of symbols]
10 Forged mold for semi-molten metal 12 Upper mold 14 Lower mold 20 Mold cavity 22 Convex part 24 Concave part 26 Linear part 28 Tapered part 29 Flat part 30 Linear part 32 Tapered part 34 Bottom part 35 Bottom part 36 Concave part 37 Taper Part 38 Circular cylinder 40 Vertical piston 41 Piston 42 with hydraulic cylinder Sub-lower mold 44 Space 46 Main cylinder 48 Horizontal piston 50 Extrusion pin 52 (a, b) Base 54 Space 56 Nut 58 Slide hole 60 (a B) Hydraulic piping 62 Excess protrusion 64 Inclination prevention protrusion

Claims (2)

A semi-molten metal forging die for supplying a semi-molten metal in a molten state in which a solid phase and a liquid phase coexist at a temperature immediately above or below the melting point into a mold cavity to perform die forging, The forging die is composed of a pair of detachable molds, and the semi-molten metal for placing the semi-molten metal in a part of one die cavity of the forging die . When providing a dish-shaped recess having a diameter larger than the diameter and performing mold forging by moving the other of the forging dies in the clamping direction, an excessive protrusion of a non-product including a solidified layer is formed, the hydraulic Cylinders capturing solidified layer in a semi-molten metal in the dished recess having a diameter larger than the diameter of the semi molten metal, provided to face the dished recess having a diameter larger than the diameter of the semi-molten metal A forging die for semi-molten metal, characterized by that. Using the casting mold for semi-molten metal according to claim 1, the semi-molten metal is placed in a dish-like recess having a diameter larger than that of the semi-molten metal of one of the forged dies. after moves the other該鍛Zokin type mold clamping direction performs die forging, in dish-shaped recess having a diameter larger than the diameter of the semi-molten metal, so as to capture the solidified layer in a semi-molten metal A molding method using a forging die for semi-molten metal, characterized in that

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