JP2013226567A - Die-casting apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a die-casting apparatus which can suppress blowholes generated in a solidification step of a molten metal by a simple configuration.SOLUTION: A die-casting apparatus includes: a sleeve 9 in communication with a mold cavity K; a pressurizing unit 5 fitted to the sleeve 9 and configured to be movable in a shaft center direction L of the sleeve 9; and a drive means for driving the pressurizing unit 5 in the shaft center direction L of the sleeve 9. The pressurizing unit 5 includes: a pressurizing pin 1 of a housing fitted to the sleeve 9 and configured to be movable in the shaft center direction L of the sleeve 9; and a pressurizing pin 2 fitted to the pressurizing pin 1 and configured to be movable in the shaft center direction L of the sleeve 9. Coil springs 6, 7 with elastic coefficients different from each other are arranged respectively between the sleeve 9 and the pressurizing pin 1 and between the pressurizing pin 1 and the pressurizing pin 2. The pressurizing pin 1 and the pressurizing pin 2 are configured to be projected into the cavity K in a multi-stepped manner toward the inside of the sleeve 9 by driving the pressurizing pin 2 by the drive means.

Description

  The present invention relates to a die casting apparatus, and more particularly to a die casting apparatus that locally pressurizes molten metal injected into a mold.

  Conventionally, die casting is a casting method capable of producing a product with excellent dimensional accuracy, and thus has been applied in various industrial fields.

  The above-mentioned die casting is a high production method by injecting molten metal (molten metal) such as aluminum, zinc, magnesium, etc. at high speed and high pressure into the mold cavity made of special steel, and rapidly solidifying the molten metal in the cavity. Maintaining sex.

  By the way, in die casting, since the molten metal is injected into the cavity at a high speed and cooled and solidified in a short time, a cavity called a “cast hole” is generated in the solidification process of the molten metal, and the product has a high density. There is a problem that the rigidity is lowered.

  In order to solve such a problem, Patent Documents 1 to 3 disclose techniques for suppressing a cast hole generated inside a product, particularly a sink hole generated in the product due to solidification shrinkage in the cast hole.

  The local pressure casting method disclosed in Patent Document 1 uses a mold in which a large-diameter pressure pin and a small-diameter pressure pin are provided in a double manner so as to be able to enter the cavity, and after injecting molten metal into the cavity. In this method, the large-diameter pressure pin and the small-diameter pressure pin are subjected to two-stage pressure with a time difference.

  In addition, the pressurizing device of the die-casting apparatus disclosed in Patent Document 2 is a pressurizing device of a die-casting device composed of a cylinder and a pin that pressurizes the melting part, and the cylinder has a double structure composed of left and right cylinders. The left cylinder is provided with an outer pin composed of a piston and a pin having a hollow portion, and the right cylinder is provided with a pin penetrating and sliding inside the piston and the outer pin, and an inner pin having a flange at the position of the hollow portion, and the piston diameter of the outer pin Is larger than the piston diameter of the inner pin, and hydraulic pressure is supplied to each cylinder to operate the outer pin and the inner pin.

  Further, the die casting apparatus disclosed in Patent Document 3 fills the mold with a molten metal, and moves the pressure rod forward into the cavity before the molten metal solidifies to apply the secondary pressurized pressure to the molten metal. In the die casting apparatus, the main pressure bar penetrating the mold wall includes at least one sub pressure bar that appears and disappears at the tip of the main pressure bar. It is an apparatus formed integrally with a piston that is housed in a cylinder chamber formed in the pressure rod and on which the hydraulic oil of the main pressure rod acts directly.

Japanese Patent Laid-Open No. 02-274361 JP-A-01-205863 JP-A-63-199059

  According to the die casting apparatus disclosed in Patent Documents 1 to 3, the shrinkage nest that can be generated in the solidification process of the molten metal injected into the mold is locally and multistagely pressurized with a plurality of pressure pins. And the occurrence of shrinkage nests inside the product can be suppressed.

  However, in the die casting apparatus disclosed in Patent Documents 1 and 2, a hydraulic cylinder that separately operates a large-diameter pressure pin and a small-diameter pressure pin, and an outer pin and an inner pin is required, and the entire apparatus is increased in size. In addition, there is a problem that the manufacturing cost increases due to the complexity.

  Further, in the die casting apparatus disclosed in Patent Document 3, the hydraulic oil of the main pressure bar directly acts on the sub pressure bar, and the main pressure bar and the sub pressure bar are respectively pressurized. Since it operates depending on the rigidity of the uncoagulated tissue located at the front position of the rod, there is a problem that the operation of each pressure rod of the main pressure rod and the sub pressure rod becomes unstable.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a die casting apparatus that can reliably suppress a cast hole generated in a solidification process of a molten metal with a simple configuration.

  In order to achieve the above object, a die casting apparatus according to the present invention includes a cylinder communicating with a mold cavity, a pressurizing unit that is fitted to the cylinder and is movable in the axial direction of the cylinder, A die casting apparatus comprising a driving means for driving the pressure unit in the axial direction of the cylinder, and driving the pressure unit by the driving means to project at least a part of the pressure unit into the mold cavity, The pressurizing unit is fitted to the cylindrical body so as to be movable in the axial direction of the cylindrical body, and is fitted to the first pressure pin and the first pressurizing pin. A second pressure pin that is movable in the axial direction is provided, and each of the cylinder and the first pressure pin and between the first pressure pin and the second pressure pin is a cylinder. Relative movement of the first pressure pin and the phase of the first pressure pin and the second pressure pin Elastic bodies having different elastic coefficients for restricting general movement are arranged, and the second pressing pin is driven by the driving means, so that at least a part of the first pressing pin is a cylindrical body. Projecting into the cavity, projecting at least a portion of the second pressure pin from the first pressure pin into the cavity, and moving the first pressure pin and the second pressure pin toward the inside of the cylinder. This is a device that projects into the cavity in multiple stages.

  Here, examples of the elastic body applied in the die casting apparatus of the present invention include a coil spring having a specific elastic coefficient, a resin rubber, an air spring using a predetermined pressure of air or an inert gas, and the like. Moreover, as a drive means, actuators, such as a hydraulic cylinder, can be mentioned, for example.

  According to the above-described die casting apparatus, the elastic bodies having different elastic coefficients are arranged between the cylinder and the first pressure pin and between the first pressure pin and the second pressure pin, Even when the second pressure pin is driven by the driving means, for example, at least a part of the first pressure pin protrudes from the cylindrical body and then the second pressure pin is driven from the first pressure pin. Projecting at least a part of the pin, or projecting at least a part of the second pressure pin from the first pressure pin and then projecting at least a part of the first pressure pin from the cylinder Can do. As a result, the first pressure pin and the second pressure pin can be protruded into the cavity in a multi-stage and continuously from the outside to the inside of the cylindrical body. The casting cavity that can be generated during the solidification process of the molten metal (molten metal) in the cavity such as the entrainment cavity caused by the entrainment of air or gas can be pressurized in multiple stages, so it can be generated inside the product with a simple structure. The cast hole can be suppressed.

  In the above-described die casting apparatus, the second pressure pin is composed of a plurality of pressure pins that are movable in the axial direction of the cylindrical body, and adjacent to the plurality of pressure pins. Elastic bodies having different elastic coefficients for restricting relative movement between the adjacent pressure pins are respectively arranged between the pressure pins to be operated. Of these, it is preferable that the pressure pins arranged on the innermost side of the cylinder are driven so that the plurality of pressure pins protrude into the cavity in multiple stages toward the inner side of the cylinder.

  According to the above-described die casting apparatus, the elastic body having different elastic coefficients is disposed between the adjacent pressure pins among the plurality of pressure pins constituting the second pressure pin, thereby driving means. Even when the pressure pin arranged inside the cylinder is driven among the plurality of pressure pins, the plurality of pressure pins are moved into the cavity from the outside to the inside of the cylinder. Can be projected. As a result, the casting cavity that can be generated in the solidification process of the molten metal in the cavity can be further pressurized in multiple stages, so that the casting cavity that can be generated inside the product can be more effectively suppressed. In addition, since the driving means can be arranged inside the cylinder by driving the pressure pin arranged most inside the cylinder among the plurality of pressure pins by the driving means, the physique of the entire apparatus Can be significantly reduced in size.

  Moreover, it is preferable that the elastic coefficient of the elastic body changes in an inclined manner from the outside to the inside of the cylindrical body.

  According to the above-described die casting apparatus, for example, when the second pressure pin is driven by the driving means, the first pressure pin and the second pressure pin are moved from the outside to the inside or from the inside. Since it can be projected into the cavity sequentially in a multi-stage toward the outside, it is possible to more effectively press the cast hole that may be generated in the solidification process of the molten metal in the cavity.

  The die casting apparatus may be configured to first pull back the second pressure pin when pulling back the first pressure pin and the second pressure pin protruding into the cavity toward the cylinder. Preferably, when the plurality of pressure pins constituting the second pressure pin projecting into the cavity are pulled back in the direction of the cylinder, the pressure pin arranged most inside the cylinder is pulled back first. It is desirable.

  Among the plurality of pressure pins protruding into the cavity, the pressure pin arranged inside the cylinder has a relatively small outer shape and is easily deformed compared to other pressure pins, and is pulled back toward the cylinder. It is easy for galling to occur. According to the above-described die casting apparatus, by sequentially pulling back in the direction of the cylinder from the pressure pin arranged inside the cylinder that is likely to be galling, it is due to thermal deformation or the like of the pressure pin arranged inside the cylinder. Deformation can be suppressed, and the occurrence of galling when pulling the pressure pin can be remarkably suppressed.

  Further, the above-described die-casting device has a protruding amount of the first pressure pin into the cavity with respect to the cylindrical body, a protruding amount of the second pressure pin into the cavity with respect to the first pressure pin, or a second It is preferable that the protruding amount of the adjacent pressure pins into the cavity among the plurality of pressure pins constituting the pressure pin is 7 mm or less.

  When the amount of protrusion of the first pressure pin into the cavity with respect to the cylindrical body or the amount of protrusion of the adjacent pressure pins into the cavity increases, the contact between the pressure pin protruding into the cavity and the molten metal in the cavity The area increases, the deformation due to thermal expansion of the pressure pin increases, and the pull back force increases when the pressure pin is pulled back toward the cylinder. According to the above-described die casting apparatus, the amount of protrusion of the first pressure pin into the cavity with respect to the cylindrical body and the amount of protrusion of the adjacent pressure pins into the cavity are set to 7 mm or less, thereby protruding into the cavity. The increase in the contact area between the pressed pin and the molten metal in the cavity is suppressed, the deformation due to the thermal expansion of the pressure pin is suppressed, and the increase in resistance when the pressure pin is pulled back in the cylinder direction is suppressed. Can do.

  As can be understood from the above description, according to the die-casting apparatus of the present invention, it is possible to easily eliminate a cast hole generated in a solidification process of a molten metal such as a sinkhole caused by solidification shrinkage or a wound nest caused by entrainment of air or gas. A cast body that can be effectively suppressed by the configuration and is excellent in denseness and rigidity can be provided.

1 is a longitudinal sectional view schematically showing Embodiment 1 of a die casting apparatus according to the present invention. FIG. 2 is a longitudinal sectional view illustrating a pressurizing process by the die casting apparatus shown in FIG. 1, (a) is a diagram showing a state before pressurization, and (b) is a drawing subsequent to FIG. It is the figure which showed the state which actuated the pressure pin 1, (c) is the figure which showed the state which actuated the pressure pin 2 following FIG.2 (b). It is the partially expanded view which expanded and showed a part of pressurization unit of the die-casting apparatus shown in FIG.2 (c). It is the longitudinal cross-sectional view which showed Embodiment 2 of the die-casting apparatus concerning this invention typically. FIG. 5 is a longitudinal sectional view for explaining a pressurizing process by the die casting apparatus shown in FIG. 4, (a) is a view showing a state before pressurization, and (b) is a drawing subsequent to FIG. 5 (a). FIG. 6 is a diagram showing a state in which the pressure pins 1A, 12A, and 13A are operated, and FIG. 5C is a diagram showing a state in which the pressure pins 12A and 13A are operated following FIG. (D) is the figure which showed the state which actuated the pressurization pin 13A following FIG.5 (c). It is the longitudinal cross-sectional view explaining the pressurization process by Embodiment 3 of the die-casting apparatus based on this invention, Comprising: (a) is the figure which showed the state before pressurization, (b) is FIG. ) Is a diagram showing a state in which the pressure pins 1B, 12B, 13B are operated, and (c) is a diagram showing a state in which the pressure pin 13B is operated following FIG. 6 (b). (D) is the figure which showed the state which actuated the pressure pins 12B and 13B following FIG.6 (c). It is the figure which showed the relationship between the protrusion amount to the metal mold | die cavity of the pressurization pin by a test body, and pullback force.

  Embodiments of a die casting apparatus according to the present invention will be described below with reference to the drawings.

[Embodiment 1]
FIG. 1 is a perspective view schematically showing a first embodiment of a die casting apparatus according to the present invention.

  The illustrated die casting apparatus 10 includes a substantially cylindrical sleeve 9 that mainly communicates with a mold cavity K, and a pressurizing unit 5 that is fitted to the sleeve 9 and is movable in the axial center L direction of the sleeve 9. Driving means (not shown) for driving the pressure unit 5 in the direction of the axis L of the sleeve 9, and by driving the pressure unit 5 with the drive means, a part of the pressure unit 5 is driven. It protrudes into the mold cavity K. Here, examples of the driving means (not shown) include an actuator such as a hydraulic cylinder.

  The pressurizing unit 5 is further fitted with a sleeve 9 and a pressurizing pin 1 made of a cylindrical body which is movable in the direction of the axis L of the sleeve 9 and the pressurizing pin 1. The pressure pin 2 is movable in the direction of the axis L of the sleeve 9, and the driving means drives the pressure pin 2 in the pressure unit 5. The pressurizing pins 1 and 2 are arranged substantially concentrically with the axis L of the sleeve 9.

  Here, a step portion 9 a is formed on the inner peripheral surface of the sleeve 9, and a concave portion 1 b that can accommodate the step portion 9 a of the sleeve 9 is formed on the outer peripheral surface of the pressure pin 1 that is in sliding contact with the inner peripheral surface of the sleeve 9. A coil spring 6 that extends and contracts in the axial center L direction of the sleeve 9 is disposed in a region R1 that is formed and defined by the inner peripheral surface of the sleeve 9, the step portion 9a, and the concave portion 1b of the pressure pin 1. . Thus, by arranging the coil spring 6 between the sleeve 9 and the pressure pin 1, the driving force of the drive means transmitted to the pressure pin 1 via the pressure pin 2 is transmitted to the coil spring 6. When this occurs, the coil spring 6 is contracted between the step 9a of the sleeve 9 and the recess 1b of the pressure pin 1 in the direction of the axis L of the sleeve 9 by an amount corresponding to the driving force, and the pressure pin 1 is A part of the pressure pin 1 on the mold cavity K side is driven from the sleeve 9 to the mold by being driven in the axial L direction of the sleeve 9 relative to the sleeve 9 by the contraction amount of the coil spring 6 according to the driving force. It is projected into the cavity K.

  Further, a step portion 1 a is formed on the inner peripheral surface of the pressure pin 1, and the step portion 1 a of the pressure pin 1 is accommodated on the outer peripheral surface of the pressure pin 2 that is in sliding contact with the inner peripheral surface of the pressure pin 1. A concave portion 2b that can be deformed is formed, and the region R2 defined by the inner peripheral surface of the pressure pin 1 and the step portion 1a and the concave portion 2b of the pressure pin 2 expands and contracts in the axial center L direction of the sleeve 9. A coil spring 7 is disposed. Thus, when the coil spring 7 is disposed between the pressure pins 1 and 2, when the driving force of the driving means transmitted to the pressure pin 2 is transmitted to the coil spring 7, the coil spring 7 Is contracted in the direction of the axis L of the sleeve 9 by an amount corresponding to the driving force between the step portion 1a of the pressing pin 1 and the recess 2b of the pressing pin 2, and the pressing pin 2 corresponds to the driving force. The coil spring 7 is driven in the direction of the axis L of the sleeve 9 relative to the pressurizing pin 1 by the contraction amount of the coil spring 7, and a part of the pressurizing pin 2 on the mold cavity K side is further die than the pressuring pin 1 Projected into the mold cavity K.

  In this way, only the pressure pin 2 is driven by the driving means, and the pressure pin 2 is pressed while the coil spring 7 disposed between the pressure pins 1 and 2 is contracted by the driving force of the driving means. The sleeve 9 and the pressure pin 1 are driven by the driving force of the driving means which is driven relative to the shaft 1 in the direction of the axis L of the sleeve 9 and transmitted to the pressure pin 1 via the pressure pin 2 and the coil spring 7. At least a part of the pressure pin 1 is moved from the sleeve 9 by driving the pressure pin 1 in the direction of the axis L of the sleeve 9 while contracting the coil spring 6 disposed between the sleeve 9 and the sleeve 9. Projecting into the mold cavity K, projecting at least a part of the pressure pin 2 from the pressure pin 1 into the mold cavity K, and the pressure pins 1 and 2 from the radially outer side of the sleeve 9 to the axis L Multi-stage toward the mold cavity from the sleeve 9 It can be projected to the I K.

  Next, with reference to FIG. 2, the pressurization process by the die-cast apparatus 10 shown in FIG. 1 is demonstrated in detail. FIG. 2A is a view showing a state before pressurization, and FIG. 2B is a view showing a state in which the pressurization pins 1 and 2 are operated following FIG. 2A. FIG. 2C is a view showing a state in which the pressure pin 2 is operated following FIG. 2B. In addition, the position where the pressurization unit 5 of the die casting apparatus 10 is disposed, the timing at which the molten metal in the mold cavity K is pressed by the pressurization unit 5, the pressurization depth and pressurization speed of the pressurization unit 5, and the pressurization unit 5 The shape and the like are defined in advance by numerical analysis, empirical rules, and the like.

  First, as shown in FIG. 2A, in the state before pressurization by the die casting apparatus 10, the inner wall surface of the mold cavity K and the end surface (pressurization surface) of the pressurization pins 1 and 2 on the mold cavity K side. The pressurizing pins 1 and 2 of the pressurizing unit 5 are arranged in the sleeve 9 so as to be flush with each other. Here, a region defined by the inner peripheral surface of the sleeve 9 and the side surface 9ab of the stepped portion 9a on the side away from the mold cavity K and the side surface 1bb of the recess 1b of the pressing pin 1 on the side away from the mold cavity K. The coil spring 6 disposed in R1 is in a contracted state, and a pressing force is applied to the pressure pin 1 in a direction away from the mold cavity K by the coil spring 6, but the mold cavity of the step 9a of the sleeve 9 is provided. When the side surface 9aa on the K side and the side surface 1ba on the mold cavity K side of the recess 1b of the pressure pin 1 abut, the position of the pressure pin 1 in the sleeve 9 is defined. Similarly, it is defined by the inner peripheral surface of the pressure pin 1, the side surface 1 ab of the stepped portion 1 a on the side away from the mold cavity K, and the side surface 2 bb of the recess 2 b of the pressure pin 2 on the side away from the mold cavity K. The coil spring 7 disposed in the region R2 is in a contracted state, and the urging force is applied to the pressure pin 2 in a direction away from the mold cavity K by the coil spring 7, but the step portion 1a of the pressure pin 1 is applied. When the side surface 1aa on the mold cavity K side and the side surface 2ba on the mold cavity K side of the recess 2b of the pressure pin 2 abut, the position of the pressure pin 2 in the sleeve 9 is defined.

  Next, the pressurizing pin 2 is driven by a driving means (not shown) in order to pressurize the cast hole generated in the solidification process of the molten metal in the mold cavity K by the pressurizing unit 5. Here, the spring elastic coefficient of the coil spring 6 disposed between the sleeve 9 and the pressure pin 1 is relatively smaller than the spring elastic coefficient of the coil spring 7 disposed between the pressure pin 1 and the pressure pin 2. Therefore, the coil spring 6 contracts before the coil spring 7 contracts. Thus, as shown in FIG. 2B, before the coil spring 7 is contracted by the driving force transmitted from the driving means to the pressure pin 2, the pressure pin 2, the coil spring 7, and the pressure pin 1 are used. The coil spring 6 is contracted in the direction of the axis L of the sleeve 9 by the driving force transmitted to the coil spring 6, so that the relative position of the pressure pin 2 with respect to the pressure pin 1 does not change from the pressure pins 1 and 2. The pressurizing unit 5 is driven in the direction of the axis L of the sleeve 9 relative to the sleeve 9 by the contraction amount of the coil spring 6 according to the driving force. Therefore, a part of the pressure unit 5 including the pressure pins 1 and 2 protrudes from the sleeve 9 to the mold cavity K, and the molten metal in the mold cavity K is made to have a relatively large area S1 (pressure pins 1 and 2). The area of both pressure surfaces can be pressurized.

  Next, after the coil spring 6 disposed between the sleeve 9 and the pressure pin 1 contracts by a predetermined amount, when the pressure pin 2 is further driven by a driving means (not shown), it is shown in FIG. Thus, the coil spring 6 is not further contracted, and the coil spring 7 is contracted in the direction of the axis L of the sleeve 9 by the driving force transmitted from the driving means to the coil spring 7 via the pressure pin 2, and the pressure pin 2 is The coil spring 7 is driven in the direction of the axis L of the sleeve 9 relative to the pressure pin 1 by the amount of contraction of the coil spring 7 according to the driving force. Therefore, a part of the pressure pin 2 further protrudes from the pressure pin 1 to the mold cavity K, and the molten metal in the mold cavity K is relatively small in area S2 (area of the pressure surface of the pressure pin 2). Can be pressurized.

  Thus, since the coil springs 6 and 7 have different spring elastic coefficients, even when only the pressure pin 2 is driven by the driving means, the coil springs 6 and 7 are generated in the solidification process of the molten metal in the mold cavity K. The casting cavity can be first pressurized with a relatively large area S1, and then continuously pressurized with a relatively small area S2, and the casting cavity generated in the solidification process of the molten metal in the mold cavity K can be properly treated. Since pressurization can be performed at a proper timing and with an appropriate area, pressurization depth, and the like, it is possible to effectively eliminate a cast hole generated inside the molten metal.

  By the way, although the pressurizing unit 5 pressurizes the casting cavity generated during the solidification process of the molten metal in the mold cavity K is extremely short, the molten metal in the mold cavity K is very high temperature, and therefore is shown in FIG. As described above, the pressurizing unit 5 protruding from the sleeve 9 to the mold cavity K is thermally expanded by the heat of the molten metal around it. Further, as the molten metal in the mold cavity K solidifies and the molten metal around the pressurizing unit 5 solidifies and shrinks, the pressurizing unit 5 protruding from the sleeve 9 to the mold cavity K shrinks around the melt. Persisted by molten metal. Due to the anchor effect by the thermal expansion of the pressurizing unit 5 and the solidification and shrinkage of the molten metal around the pressurizing unit 5, the pressurizing unit 5 that pressurizes the casting cavity inside the molten metal in the mold cavity K is connected to the sleeve 9. The pulling force when pulling back to the side is considered to increase.

  Therefore, after the pressurizing unit 5 pressurizes the cast hole inside the molten metal in the mold cavity K and then pulls back the pressurizing unit 5 to the sleeve 9 side, the outer shape is relatively small first. The pressure pin 2 having low rigidity is moved relative to the pressure pin 1 in the direction of the axis L of the sleeve 9, and a part of the pressure pin 2 protruding into the mold cavity K is moved to the pressure pin 1. Pull back inward. At this time, the side surface 1aa on the mold cavity K side of the step portion 1a of the pressure pin 1 and the side surface 2ba on the mold cavity K side of the recess 2b of the pressure pin 2 are brought into contact with each other. The position of the pressure pin 2 is defined. Then, after a part of the pressure pin 2 protruding into the mold cavity K is pulled back to the inside of the pressure pin 1, the pressure unit 5 including the pressure pins 1 and 2 is integrated with the sleeve 1. Thus, the sleeve 9 is moved in the direction of the axis L of the sleeve 9, and a part of the pressurizing unit 5 protruding into the mold cavity K is pulled back into the sleeve 9. At that time, the side surface 9aa on the mold cavity K side of the step 9a of the sleeve 9 and the side surface 1ba on the mold cavity K side of the concave portion 1b of the pressure pin 1 are brought into contact with each other. Two positions are defined.

  In this way, when the pressurizing unit 5 that pressurizes the casting cavity inside the molten metal in the mold cavity K is pulled back to the sleeve 9 side, the pressurizing pins 1 and 2 are pulled back into the sleeve 9 in multiple stages. Thus, each pulling force when the pressure pins 1 and 2 are pulled back into the sleeve 9 can be remarkably reduced. Further, by pulling back the pressure pin 2 having a relatively small outer shape and low rigidity toward the sleeve 9 first, the occurrence of galling (axial misalignment) when the pressure pins 1 and 2 are pulled back into the sleeve 9 is effective. Can be suppressed.

  In the die casting apparatus 10 of the first embodiment described above, the pressure pins 1 and 2 of the pressure unit 5 can be pulled back to the sleeve 9 side by using the biasing force of the contracted coil springs 6 and 7. Therefore, it is possible to effectively reduce the pull back force by the driving means when pulling back the pressure pins 1 and 2 to the sleeve 9 side.

  In the die casting apparatus 10 according to the first embodiment described above, the spring elastic coefficient of the coil spring 6 disposed between the sleeve 9 and the pressure pin 1 is disposed between the pressure pin 1 and the pressure pin 2. Although the embodiment has been described in which the coil spring 6 contracts before the coil spring 7 contracts, the spring elastic coefficient of the coil spring 6 disposed between the sleeve 9 and the pressure pin 1 is relatively smaller than the spring elastic coefficient of the coil spring 7. May be made relatively larger than the spring elastic coefficient of the coil spring 7 disposed between the pressure pin 1 and the pressure pin 2 so that the coil spring 7 contracts before the coil spring 6 contracts.

  In this case, when the pressure pin 2 is driven by the driving means, the coil spring 7 is moved in the direction of the axis L of the sleeve 9 by the driving force transmitted to the coil spring 7 through the pressure pin 2 before the coil spring 6 contracts. The pressure pin 2 is driven in the direction of the axis L of the sleeve 9 relative to the pressure pin 1 by the amount of contraction of the coil spring 7 corresponding to the driving force. Therefore, a part of the pressure pin 2 protrudes from the pressure pin 1 in a substantially stationary state to the mold cavity K, and the molten metal in the mold cavity K is reduced to a relatively small area S2 (pressure surface of the pressure pin 2). The area can be pressurized. Further, when the pressure pin 2 is further driven by the driving means, the coil spring 7 is not further contracted, and the coil spring 6 is driven by the driving force transmitted to the coil spring 6 via the pressure pin 2, the coil spring 7 and the pressure pin 1. The pressurizing unit 5 comprising the pressurizing pins 1 and 2 in a posture in which a part of the pressurizing pin 2 is projected with respect to the pressurizing pin 1 is contracted in the direction of the axial center L of the sleeve 9 is a coil spring corresponding to the driving force. The sleeve 9 is driven in the direction of the axis L relative to the sleeve 9 by a contraction amount of 6. Therefore, a part of the pressure pin 1 protrudes from the sleeve 9 to the mold cavity K in a posture in which the relative position of the pressure pin 2 with respect to the pressure pin 1 is not changed, and the molten metal in the mold cavity K is relatively It is possible to apply pressure with a large area S1 (area of the pressing surfaces of both the pressing pins 1 and 2).

[Embodiment 2]
FIG. 4 is a longitudinal sectional view schematically showing Embodiment 2 of the die casting apparatus according to the present invention. The die casting apparatus 10A according to the second embodiment shown in FIG. 4 is different from the die number of the pressure pin mainly constituting the pressure unit and the sleeve and the pressure unit with respect to the die casting apparatus 10 according to the first embodiment shown in FIG. The configurations of the elastic bodies arranged in are different, and the other configurations are almost the same. Therefore, about the structure similar to the die-cast apparatus 10 of Embodiment 1, the same code | symbol is attached | subjected and the detailed description is abbreviate | omitted.

  Specifically, the pressurizing unit 5A of the die casting apparatus 10A of the second embodiment shown in FIG. 4 is formed of a cylindrical body that is fitted to the sleeve 9A and is movable in the direction of the axis LA of the sleeve 9A. The pressure pin 1A and the pressure pin 2A that is fitted to the pressure pin 1A and is movable in the direction of the axis LA of the sleeve 9A are configured. A pressure pin 12A made of a cylinder that is fitted to a pressure pin 1A made of a cylinder and is movable in the direction of the axis LA of the sleeve 9A, and a shaft of the sleeve 9A fitted to the pressure pin 12A. The pressure pin 13A is movable in the direction of the center LA, and a driving means (not shown) drives the pressure pin 13A arranged on the innermost side of the pressure unit 5A. Yes. The pressurizing pins 1A, 12A, and 13A are arranged substantially concentrically with the axis LA of the sleeve 9A.

  Here, a step 9aA is formed at the end of the inner peripheral surface of the sleeve 9A on the mold cavity K side, and the outer peripheral surface of the pressure pin 1A that is in sliding contact with the inner peripheral surface of the sleeve 9A is on the mold cavity K side. The end is formed with a recess 1bA that can accommodate the step 9aA of the sleeve 9A, and in a region R0A defined by the inner peripheral surface of the sleeve 9A, the step 9aA and the recess 1bA of the pressure pin 1A. Contains air (air spring) A at approximately atmospheric pressure. As described above, the air A is accommodated between the sleeve 9A and the pressure pin 1A, so that when the driving force of the driving means is transmitted to the pressure pin 1A via the pressure pin 3A or the like, the pressure is applied. The pressure pin 1A is driven in the direction of the axis LA of the sleeve 9A relative to the sleeve 9A with almost no resistance (elastic coefficient is very small), and a part of the pressure pin 1A on the mold cavity K side is the sleeve. It protrudes from 9A to the mold cavity K.

  The relationship between the pressure pin 12A and the pressure pin 13A of the pressure unit 5A of the die casting apparatus 10A of the second embodiment shown in FIG. 4 is the same as that of the pressure casting unit 5 of the die casting apparatus 10 of the first embodiment shown in FIG. The relationship between the pressure pin 1 and the pressure pin 2 is the same.

  As described above, the driving means drives only the pressure pin 13A arranged on the innermost side of the pressure unit 5A, and the coil spring is arranged between the pressure pins 12A and 13A by the driving force of the driving means. The pressure pin 13A is driven in the direction of the axis LA of the sleeve 9A relative to the pressure pin 12A while contracting 7A, and transmitted to the pressure pin 12A via the pressure pin 13A and the coil spring 7A. The pressure pin 12A is driven in the direction of the axis LA of the sleeve 9A relative to the pressure pin 1A while the coil spring 6A disposed between the pressure pins 1A and 12A is contracted by the driving force of the driving means. The pressure pin 1A is moved relative to the sleeve 9A by the driving force of the driving means transmitted to the pressure pin 1A via the pressure pins 13A and 12A and the coil springs 7A and 6A. By driving the axial LA direction, pressure pin 1A, 12A, 13A and it is possible to further protrude into the multi-stage manner mold cavity K toward the radially outer side of the sleeve 9A to axis LA.

  Next, with reference to FIG. 5, the pressurization process by the die casting apparatus 10A shown in FIG. 4 will be described in detail. FIG. 5A is a diagram showing a state before pressurization, and FIG. 5B is a diagram showing a state in which the pressurization pins 1A, 12A, and 13A are operated following FIG. 5A. FIG. 5C is a diagram showing a state in which the pressure pins 12A and 13A are operated following FIG. 5B, and FIG. 5D is a diagram following FIG. 5C. It is the figure which showed the state which acted the pressurization pin 13A.

  First, as shown in FIG. 5 (a), in the state before pressurization by the die casting apparatus 10A, the inner wall surface of the mold cavity K and the end surface (pressurization) of the pressurization pins 1A, 12A, 13A on the mold cavity K side. The pressure pins 1A, 12A, and 13A of the pressure unit 5A are arranged in the sleeve 9A so that the pressure surface is flush with the pressure surface. Here, the side surface 9abA of the step 9aA of the sleeve 9A that is separated from the mold cavity K and the side surface 1bbA of the depression 1bA of the pressure pin 1A that is separated from the mold cavity K are separated by a predetermined distance (pressure pin 1A). (Corresponding to the amount of protrusion of the sleeve 9A).

  Next, in order to pressurize the cast hole generated in the solidification process of the molten metal in the mold cavity K with the pressurizing unit 5A, the pressurizing pin 13A is driven by a driving means (not shown). Here, the air resistance between the sleeve 9A and the pressure pin 1A (also referred to as the elastic coefficient of the air spring) is the same as that of the coil spring 6A and the pressure pin 12A disposed between the pressure pin 1A and the pressure pin 12A. Since it is relatively smaller than the spring elastic force of the coil spring 7A disposed between the pressure pins 13A, as shown in FIG. 5B, the coil spring 6A is driven by the driving force transmitted from the driving means to the pressure pin 13A. The pressure pins 1A, 12A, 13A constituting the pressure unit 5A are driven by the driving force transmitted to the pressure pins 1A via the pressure pins 13A, 12A and the coil springs 7A, 6A before the contraction of the pressure pins 7A, 7A. The pressure unit 5A is driven in the direction of the axis LA of the sleeve 9A relative to the sleeve 9A by the predetermined distance in a posture in which the relative position of the sleeve 9A does not change. Therefore, a part of the pressurizing unit 5A composed of the pressurizing pins 1A, 12A, 13A protrudes from the sleeve 9A to the mold cavity K, and the molten metal in the mold cavity K is relatively large in area S1A (pressurizing pin 1A , 12A, and 13A).

  Next, after the side surface 9abA on the side of the step 9aA of the sleeve 9A that is separated from the mold cavity K and the side surface 1bbA on the side of the depression 1bA of the pressure pin 1A that are separated from the mold cavity K are in contact, further driving is performed. When the pressure pin 13A is driven by means (not shown), the spring elastic coefficient of the coil spring 6A disposed between the pressure pin 1A and the pressure pin 12A is disposed between the pressure pin 12A and the pressure pin 13A. As shown in FIG. 5C, the driving force transmitted to the coil spring 6A through the pressure pin 13A, the coil spring 7A, and the pressure pin 12A is relatively smaller than the spring elastic coefficient of the coil spring 7A. As a result, the coil spring 6A is contracted in the direction of the axis LA of the sleeve 9A, and the pressure pin 2A does not change the relative position of the pressure pin 13A with respect to the pressure pin 12A. Driven into axial LA direction relative the sleeve 9A relative shrinkage of only sleeve 9A of Rubane 6A. Therefore, a part of the pressure pin 2A composed of the pressure pins 12A and 13A is further protruded from the pressure pin 1A to the mold cavity K, and the molten metal in the mold cavity K has an area S2A (of the pressure pins 12A and 13A). It is possible to apply pressure with the area of both pressing surfaces.

  Then, after the coil spring 6A disposed between the pressure pin 1A and the pressure pin 12A contracts by a predetermined amount, when the pressure pin 13A is further driven by driving means (not shown), FIG. 5 (d). As shown, the coil spring 7A is contracted in the direction of the axial center LA of the sleeve 9A by the driving force transmitted from the driving means to the coil spring 7A through the pressure pin 13A, and the pressure pin 2 corresponds to the coil spring 7A corresponding to the driving force. The sleeve 9A is driven in the direction of the axis LA relative to the pressure pin 12A by the amount of contraction. Therefore, a part of the pressure pin 13A further protrudes from the pressure pin 12A to the mold cavity K, and the molten metal in the mold cavity K is relatively small in area S3A (the area of the pressure surface of the pressure pin 13A). Can be pressurized.

  As a result, the mold cavity generated in the solidification process of the melt in the mold cavity K is first pressurized with a relatively large area S1A, then pressurized with an area S2A, and then continuously with a relatively small area S3A. It is possible to pressurize the casting cavity generated during the solidification process of the molten metal in the mold cavity K in a multistage manner, and the timing, pressure area, and pressure to pressurize the casting cavity generated in the molten metal. Since the pressure depth and the like can be adjusted more precisely, the cast hole generated inside the molten metal can be more effectively eliminated.

  When a part of the pressurizing unit 5A protruding to the mold cavity K is pulled back to the sleeve 9A side, the pressurizing pin 13A disposed at the innermost side first is inserted as in the first embodiment. The sleeve 9A is moved to the inside of the pressure pin 12A in the direction of the axial center LA of the sleeve 9A, and then the pressure pin 2A in which the pressure pins 12A and 13A are integrated is moved to the inside of the pressure pin 1A in the direction of the axial center LA of the sleeve 9A. Next, the pressure unit 5A in which the pressure pins 1A, 12A, and 13A are integrated is moved toward the sleeve 9A in the axial center LA direction of the sleeve 9A, and the pressure pins 1A, 12A, and 13A are sleeved in a multistage manner. Pull back to the 9A side.

[Embodiment 3]
FIG. 6 is a longitudinal sectional view for explaining a pressurizing step according to Embodiment 3 of the die casting apparatus according to the present invention, and FIG. 6 (a) is a diagram showing a state before pressurization, and FIG. FIG. 6B is a diagram illustrating a state in which the pressure pins 1B, 12B, and 13B are operated following FIG. 6A, and FIG. 6C is a diagram illustrating the pressure pin following FIG. 6B. FIG. 6D is a diagram illustrating a state in which the pressure pins 12B and 13B are operated following FIG. 6C.

  The die casting apparatus 10B of the third embodiment shown in FIG. 6 differs from the die casting apparatus 10A of the second embodiment shown in FIGS. 4 and 5 in the form of the coil spring disposed between the pressure pins. The other configurations are almost the same. Therefore, the same reference numerals are given to the same configurations as those of the die casting apparatus 10A of the second embodiment, and the detailed description thereof is omitted.

  Specifically, in the die casting apparatus 10B of the third embodiment, the spring elastic coefficient of the coil spring 6B disposed between the pressure pin 1B and the pressure pin 12B is between the pressure pin 12B and the pressure pin 13B. Since it is relatively larger than the spring elastic force of the arranged coil spring 7B, the coil spring 7B contracts before the coil spring 6B contracts.

  In the die casting apparatus 10B of the third embodiment, when the pressing pin 13B is driven by the driving means, first, as shown in FIG. 6B, by the driving force transmitted from the driving means to the pressing pin 13B. Before the coil springs 6B and 7B contract, the pressure pins 1B and 12B constituting the pressure unit 5B are applied by the driving force transmitted to the pressure pins 1B via the pressure pins 13B and 12B and the coil springs 7B and 6B. The pressure unit 5B is driven in the direction of the axis LB of the sleeve 9B relative to the sleeve 9B in a posture in which the relative position of 13B does not change.

  Next, when the pressure pin 13B is further driven by a driving means (not shown), the spring elastic coefficient of the coil spring 6B disposed between the pressure pin 1B and the pressure pin 12B becomes the pressure pin 12B and the pressure pin 13B. As shown in FIG. 6C, the coil spring 7B is moved by the driving force transmitted to the coil spring 7B via the pressure pin 13B. The pressure pin 13B is contracted in the direction of the axial center LB of the sleeve 9B, and the pressure pin 13B is in the posture in which the relative position of the pressure pin 12B with respect to the pressure pin 1B does not change. The sleeve 9B is driven in the direction of the axis LB relative to 12B.

  Next, when the pressure pin 13B is further driven by a drive means (not shown), as shown in FIG. 6D, the coil spring 6B is passed from the drive means via the pressure pin 13B, the coil spring 7B, and the pressure pin 12B. The coil spring 6B is contracted in the direction of the axis LB of the sleeve 9B by the driving force transmitted to the pressure pin 12B in a posture that does not change the relative position of the pressure pin 13B with respect to the pressure pin 12B. The coil spring 6B is driven in the direction of the axis LB of the sleeve 9B relative to the pressure pin 1B by the contraction amount of the coil spring 6B.

  As described above, by appropriately adjusting the elastic force (for example, the spring elastic force of the coil spring or the pressure of the air spring) of the elastic body disposed between the pressure pins or between the pressure pin and the sleeve, a plurality of pressures are applied. The pressure pin can be protruded into the mold cavity in various forms adapted to the state of the cast hole, and the cast hole generated inside the molten metal in the mold cavity can be more effectively eliminated.

  In the first to third embodiments described above, the embodiment has been described in which the mold cavity and the sleeve communicating with the mold cavity are provided separately. For example, the mold cavity and the sleeve may be integrally formed.

[Experiment and results of measuring the pull-back force of the pressure pin by the specimen]
The present inventors made two types of pressure pin test bodies (φ12 mm columnar test body 1 and φ15 mm columnar test body 2, material: SKD61) having different outer diameters. In contrast, the pull-back force was measured when the amount of protrusion to the molten metal (material: ADC12) in the mold cavity was changed.

  The method for measuring the pullback force is that the test body is projected into the mold cavity in advance, the molten metal is filled into the mold cavity, and then the test body is pulled back from the mold cavity using a hydraulic cylinder in 3 seconds. The pulling force of was measured. The die time (casting completion time) at that time was 10 seconds.

  FIG. 7 is a view showing the relationship between the protruding amount of the pressing pin into the mold cavity and the pulling force by the test bodies 1 and 2 described above.

  As shown in the figure, in the test body 1 having a relatively small outer diameter, the pulling force of the pressure pin increases as the protruding amount to the mold cavity increases, and the protruding amount to the mold cavity exceeds 7 mm. It was confirmed that the pullback force increased rapidly. In the specimen 2 having a relatively large outer diameter, the pulling force is reduced as compared with the specimen 1 having a relatively small outer diameter, but when the protruding amount to the mold cavity exceeds 7.5 mm, the pulling force is increased. Was confirmed to increase rapidly.

  From this experimental result, the pressure pin protruding into the molten metal in the mold cavity increases the pull-back force of the pressure pin as the amount of protrusion into the mold cavity increases due to the anchor effect due to thermal expansion and the solidification shrinkage of the molten metal. However, it was proved that an increase in pull-back force can be effectively suppressed for a pressure pin having a generally used outer shape by setting the protrusion amount of the pressure pin to 7 mm or less.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and there are design changes and the like without departing from the gist of the present invention. They are also included in the present invention.

DESCRIPTION OF SYMBOLS 1, 2 ... Pressure pin, 5 ... Pressure unit, 6, 7 ... Coil spring (elastic body), 9 ... Sleeve (cylinder), 10 ... Die casting apparatus, A ... Air (air spring), K ... Cavity, L ... Axis center of sleeve

Claims (6)

A cylinder communicating with the mold cavity, a pressure unit that is fitted to the cylinder and is movable in the axial direction of the cylinder, and drives the pressure unit in the axial direction of the cylinder A die casting apparatus comprising a driving means, wherein the pressing unit is driven by the driving means to project at least a part of the pressing unit into the mold cavity,
The pressurizing unit is fitted to the cylinder and is fitted to the first pressure pin and the first pressurization pin that is movable in the axial direction of the cylinder and the cylinder. A second pressure pin that is movable in the axial direction of
Between the cylinder and the first pressure pin and between the first pressure pin and the second pressure pin, the relative movement of the cylinder and the first pressure pin and the first pressure pin and the first pressure pin, respectively. Elastic bodies having different elastic coefficients for restricting relative movement of the two pressure pins are disposed;
The second pressing pin is driven by the driving means so that at least a part of the first pressing pin protrudes from the cylindrical body into the cavity, and at least a part of the second pressing pin is moved to the first. A die casting apparatus configured to project from a pressure pin into a cavity and project a first pressure pin and a second pressure pin into the cavity in multiple stages toward the inside of the cylinder.   The second pressure pin is composed of a plurality of pressure pins that are movable in the axial direction of the cylinder, and between the pressure pins adjacent to each other among the plurality of pressure pins. Are arranged with elastic bodies having different elastic coefficients for restricting relative movement between adjacent pressure pins, and are arranged on the innermost side of the plurality of pressure pins by the driving means. 2. The die casting apparatus according to claim 1, wherein the pressure pins are driven to project the plurality of pressure pins into the cavity in multiple stages toward the inside of the cylindrical body.   3. The die casting apparatus according to claim 1, wherein an elastic coefficient of the elastic body changes in an inclined manner from the outer side to the inner side of the cylindrical body.   2. The die casting apparatus is configured to first pull back the second pressure pin when pulling back the first pressure pin and the second pressure pin protruding into the cavity toward the cylindrical body. 4. The die casting apparatus according to any one of 3.   In the die casting apparatus, when the plurality of pressure pins constituting the second pressure pin protruding into the cavity are pulled back in the cylinder direction, the pressure pin arranged most inside the cylinder body is pulled back first. The die casting apparatus according to claim 2, wherein   The amount of protrusion of the first pressure pin into the cavity with respect to the cylindrical body, the amount of protrusion of the second pressure pin into the cavity with respect to the first pressure pin, or a plurality of components constituting the second pressure pin The die casting apparatus according to claim 2, wherein a protruding amount of the adjacent pressure pins into the cavity among the pressure pins is 7 mm or less.

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