Tilting gravity casting apparatus

Abstract

In tilting gravity casting, product quality is improved by efficiently discharging gas from inside the mold to the outside. [Solution] A tilting gravity casting apparatus is provided in which molten metal M is stored in a ladle 7 of a mold 2, and the mold 2 is tilted to pour the molten metal M into the cavity 6 of the mold 2 via a runner 5. The mold 2 comprises an upper mold 4 located on the upper side before being tilted, a lower mold 3 located on the lower side before being tilted, and a shutter 18 provided on the upper mold 4 or lower mold 3 that moves in and out of the runner-forming wall surface of the mold 2 to open and close the runner 5. The mold 2 is provided with an air vent that opens into the runner-forming wall surface near the cavity 6 side of the shutter 18, and connects the runner 5 to the outside of the mold 2.

Description

Technical Field

[0001] The present invention relates to a tilting gravity casting device.

Background Art

[0002] For example, as in Patent Document 1 below, there is known a tilting gravity casting device that has a ladle in a mold, stores molten metal in this ladle, and pours the molten metal into the cavity of the mold through a runner when the mold is tilted. In such a tilting gravity casting device, it is important to efficiently discharge the gas remaining in the mold to the outside in order to ensure the quality of the product. Therefore, further improvement of the gas venting structure is required.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] An object of the present invention is to improve product quality by efficiently discharging the gas in the mold to the outside in tilting gravity casting.

Means for Solving the Problems

[0005] The tilting gravity casting device according to the present invention is a tilting gravity casting device in which molten metal is stored in a ladle of a mold and the molten metal is poured into the cavity of the mold through a runner by tilting the mold. The mold includes an upper mold located on the upper side in a state before being tilted, a lower mold located on the lower side in a state before being tilted, and a shutter provided on the upper mold or the lower mold and moving in and out from the runner forming wall surface of the mold that forms the runner to open and close the runner. An air vent is provided in the mold, which opens in the runner forming wall surface in the vicinity of the cavity side of the shutter and communicates the runner with the outside of the mold.

[0006] In this configuration, the shutter moves in and out of the runner-forming wall. When the shutter moves out of the runner-forming wall, the runner is blocked. Conversely, when the shutter moves back into the runner-forming wall, the runner is opened. In this way, as the shutter protrudes from the runner-forming wall when blocking the runner, the molten metal passing in front of the shutter is pushed towards the cavity by the tip of the shutter. That is, the molten metal flowing through the runner is locally pressed towards the cavity by the shutter. This pressing force can be used to discharge gases in the molten metal near the shutter to the outside of the mold through an air vent.

[0007] In particular, it is preferable that the air vent be provided on the upper mold. Gases such as air tend to accumulate on the upper mold side of the entire circumference of the runner forming wall, but since the air vent opens on the upper mold side of the entire circumference of the runner forming wall, the gas can be efficiently discharged from the opening of the air vent.

[0008] Furthermore, the shutter is provided on the upper mold, and the upper mold comprises an upper mold body and a rectangular tubular shutter bush attached to the upper mold body to support the shutter's extension and retraction movement. Preferably, the air vent is provided between the upper mold body and the shutter bush by providing a vent groove on the outer surface of the shutter bush. With this configuration, the upper mold is equipped with the shutter bush. Since the shutter slides on the inner surface of the shutter bush, by configuring the shutter bush as a separate part from the upper mold body, the shutter bush can be easily replaced and the mold can be maintained. Furthermore, by forming an air vent between the upper mold body and the shutter bush, an air vent can be easily provided in a position immediately next to the shutter. Also, by forming the vent groove on the shutter bush side rather than the upper mold body side, an air vent can be easily formed. Moreover, by forming the vent groove on the outer surface of the shutter bush, an air vent can be easily formed. In this way, by using the shutter bush to form an air vent, an air vent can be easily placed near the shutter, and gas near the shutter can be efficiently discharged to the outside.

[0009] Furthermore, the vent groove is preferably arc-shaped in cross-section. By making the vent groove arc-shaped in cross-section, the opening area of ​​the vent groove can be easily secured. Moreover, compared to, for example, the case where the vent groove is V-shaped in cross-section, the opening area of ​​both side edges of the vent groove can be easily widened. As a result, burrs of molten metal that have entered and solidified in the air vent, in particular burrs that get caught on both side edges of the air vent opening and become difficult to remove, can be easily removed from the air vent, improving the maintainability of the air vent, i.e., the maintainability of the mold.

[0010] Furthermore, the mold is equipped with an auxiliary pressure pin for pressurizing the molten metal in the runner, and it is preferable that the auxiliary pressure pin pressurizes the molten metal in the runner after the shutter has blocked the runner. With this configuration, after the shutter has blocked the runner, the auxiliary pressure pin protrudes into the runner and pressurizes the molten metal in the runner. The auxiliary pressure pin is located on the cavity side immediately above the air vent. Therefore, gas can be discharged from the air vent by the pressing force of the auxiliary pressure pin. [Effects of the Invention]

[0011] As described above, by providing an air vent near the shutter, the gas accumulated near the shutter can be efficiently discharged to the outside using the shutter's closing motion, thereby improving product quality. [Brief explanation of the drawing]

[0012] [Figure 1] A longitudinal cross-sectional view of a tilting gravity casting apparatus according to one embodiment of the present invention. [Figure 2] A vertical cross-sectional view showing the mold tilted at a 15-degree angle during the tilting process in the same device. [Figure 3] A vertical cross-sectional view showing the state in which the mold is tilted at a 45-degree angle during the tilting process in the same device. [Figure 4] A vertical cross-sectional view showing the state where the molten metal is pressurized by a pressure pin inside the cavity after the runner is blocked by the shutter. [Figure 5] A vertical cross-sectional view showing the state after the tilting process in the device has been completed. [Figure 6] This is a vertical cross-sectional view showing the state in which the molten metal in the runner is being pressurized by an auxiliary pressure pin after the tilting process in the device is completed. [Figure 7] This diagram shows the vicinity of the upper shutter in the device, viewed from the lower side. [Figure 8] (a) is a magnified view of the main part of Figure 7, (b) is a magnified view of the main part of (a), and (c) is a diagram showing the main part of the side of the shutter bush. [Modes for carrying out the invention]

[0013] The following describes a tilting gravity casting apparatus according to one embodiment of the present invention, with reference to the drawings. First, the overall configuration of the apparatus will be described. Figure 1 shows the horizontal state before tilting. In the following description, the vertical direction will be based on the horizontal state. The apparatus includes a mold 2, which includes a lower mold 3 located on the lower side in the horizontal state before tilting, and an upper mold 4 located on the upper side in the horizontal state. The lower mold 3 and the upper mold 4 define the runner 5 and the cavity 6. The runner-forming wall surface 60 (see Figure 7) of the mold 2 that forms the runner 5 is formed by dividing it vertically by the lower mold 3 and the upper mold 4, and similarly, the cavity-forming wall surface that forms the cavity 6 is formed by dividing it vertically by the lower mold 3 and the upper mold 4. A ladle 7 is fixed to the lower mold 3. Molten metal M such as aluminum alloy is supplied to and stored in the ladle 7. In this embodiment, the upper mold 4 is a movable mold and the lower mold 3 is a fixed mold, but the reverse may also be true.

[0014] The lower mold 3 is fixed to the upper surface of the base 8. The lower end of the guide shaft 9 is fixed to the base 8, and the upper end of the guide shaft 9 is fixed to the top plate 10. A first hydraulic cylinder 11 is fixed to the upper surface of the top plate 10, and the tip of the first cylinder rod 12, which passes through the top plate 10, is connected to a movable plate 13 disposed below the top plate 10. When the first hydraulic cylinder 11 is driven, the movable plate 13 is guided by the guide shaft 9 and moves vertically between the base 8 and the top plate 10 in Figure 1. A connecting member 14 is provided on the lower side of the movable plate 13, and the movable plate 13 and the upper mold 4 are connected by this connecting member 14. Therefore, the upper mold 4 moves vertically together with the movable plate 13.

[0015] The apparatus is equipped with a tilting mechanism (not shown) for tilting the mold 2. The tilting mechanism causes the mold 2 to tilt (rotate) approximately 90 degrees in the forward direction indicated by the symbol α from the horizontal state shown in Figure 1 to the vertical state shown in Figure 5, and then rotate approximately 90 degrees in the reverse direction indicated by the symbol β from that vertical state back to the horizontal state shown in Figure 1. The apparatus performs a reciprocating rotational operation between these horizontal and vertical states.

[0016] A second hydraulic cylinder 15 is fixed to the upper surface of the upper mold 4. The second cylinder rod 16 of the second hydraulic cylinder 15 is connected to a shutter 18. The shutter 18 is driven by the second cylinder rod 16 to open and close the runner 5. The shutter 18 is positioned relatively close to the exit of the runner 5, and the tip surface of the shutter 18 forms the runner 5. That is, the tip surface of the shutter 18 constitutes a part of the wall surface portion of the runner-forming wall surface 60 on the upper mold 4 side. The shutter 18 is driven by the second hydraulic cylinder 15 to advance downward from the runner-forming wall surface 60, that is, toward the lower mold 3 side, opening the runner 5 in the retracted state and closing the runner 5 in the exit state. Therefore, the retracted state of the shutter 18 is the open state, and the exit state of the shutter 18 is the closed state. The tip surface of the shutter 18 is flush with the other part of the runner-forming wall surface 60 in the retracted state, and enters the runner 5 when it enters the exit state.

[0017] On the lower surface of the base 8, a third hydraulic cylinder 20 for pressing is fixed. The third cylinder rod 21 of the third hydraulic cylinder 20 is connected to a pressing pin 23. The pressing pin 23 penetrates the base 8, enters the lower mold 3, and reaches the cavity 6. When the third hydraulic cylinder 20 is driven, the tip of the pressing pin 23 enters the cavity 6 and presses the molten metal M in the cavity 6 upward, that is, toward the upper mold 4 side.

[0018] On the lower surface of the base 8, a fourth hydraulic cylinder 50 for auxiliary pressing is fixed. The fourth cylinder rod 51 of the fourth hydraulic cylinder 50 is connected to an auxiliary pressing pin 53. The auxiliary pressing pin 53 penetrates the base 8. When the fourth hydraulic cylinder 50 is driven, the tip of the auxiliary pressing pin 53 enters the runner 5 and presses the molten metal M in the runner 5 upward, that is, toward the upper mold 4 side. Thus, the protruding directions of the auxiliary pressing pin 53 and the shutter 18 are opposite to each other. The auxiliary pressing pin 53 is arranged near the outlet of the runner 5 as shown in FIG. 1. The auxiliary pressing pin 53 is located between the shutter 18 and the cavity 6.

[0019] The tilting process will be described. FIG. 2 shows the state where the mold 2 is tilted 15 degrees from the horizontal state in FIG. 1, FIGS. 3 and 4 show the state where the mold 2 is tilted 45 degrees, and FIGS. 5 and 6 show the state where the tilting operation is completed and the vertical state. First, in the horizontal state shown in FIG. 1, the molten metal M is stored in the ladle 7. The shutter 18 is in an open state, and the pressing pin 23 and the auxiliary pressing pin 53 are in a retracted state.

[0020] Next, the apparatus is tilted from the horizontal position shown in Figure 1 in the direction of symbol α (forward direction). As the apparatus is tilted, the molten metal M in the ladle 7 is poured into the cavity 6 through the runner 5. As shown in Figure 3, when the apparatus is tilted at a 45-degree angle, the shutter 18 closes and blocks the runner 5. Then, as shown in Figure 4, with the shutter 18 still closed, the pressure pin 23 protrudes and pressurizes the molten metal M in the cavity 6. Then, with the shutter 18 still closed and the pressure pin 23 still protruding, the apparatus rotates further in the forward direction to a vertical position as shown in Figure 5. Then, in the vertical position, as shown in Figure 6, the auxiliary pressure pin 53 protrudes and pressurizes the molten metal M near the outlet of the runner 5.

[0021] After the molten metal M in the cavity 6 has solidified, the mold opening process is performed. The molten metal M in the cavity 6 solidifies most slowly near the pressure pin 23 and faster near the runner 5. Therefore, the auxiliary pressure pin 53 is first retracted from the runner 5, and then the pressure pin 23 is retracted from the cavity 6. Then, the first hydraulic cylinder 11 is driven to move the upper mold 4 together with the movable plate 13 to the right in Figure 6, separating the upper mold 4 from the lower mold 3. Then, the product is removed from the mold 2 with an ejector pin (not shown). After the product is removed, a release agent is applied to the runner forming wall 60 and the cavity forming wall. Then, the first hydraulic cylinder 11 is driven to move the upper mold 4 together with the movable plate 13 to the left in Figure 6, performing a mold clamping process in which the upper mold 4 contacts the lower mold 3. After mold clamping, the device is rotated in the reverse direction β to return to the horizontal state in Figure 1.

[0022] Figure 7 shows the vicinity of the shutter 18 from the lower mold 3 side. In Figure 7, the direction indicated by arrow A is the inlet side of the runner 5 and is the ladle 7 side, and the direction indicated by arrow B is the outlet side of the runner 5 and is the cavity 6 side. As described above, the tip surface of the shutter 18 faces the runner 5 and constitutes a part of the runner forming wall surface 60. The shutter 18 has a rectangular cross-section, and more specifically, the longitudinal direction X of the runner 5 is the short side direction, and the short side Y of the runner 5 is the long side direction. The longitudinal direction X of the runner 5 is the flow direction of the molten metal M in the runner 5, and the short side Y of the runner 5 is the direction perpendicular to the longitudinal direction X of the runner 5 and is the width direction of the runner 5.

[0023] The upper mold 4 is fitted with a shutter bush 61 for supporting the shutter 18. The shutter bush 61 is a replaceable part and is fitted to the upper mold body 62 in a replaceable manner. The upper mold body 62 has a bush mounting hole 63 that communicates with the runner 5, and the shutter bush 61 is fitted into this bush mounting hole 63. The shutter bush 61 is cylindrical. Since the shutter 18 has a rectangular cross-section, the shutter bush 61 also has a rectangular cross-section and is a rectangular cylinder. Note that in Figures 7 and 8(a) and (b), the shutter bush 61 is shown with numerous dots.

[0024] An air vent 64 is provided near the shutter 18. The air vent 64 is located near the cavity 6 side of the shutter 18. The air vent 64 is for discharging gas near the outlet of the runner 5 between the shutter 18 and the cavity 6 to the outside of the upper mold 4. Therefore, the air vent 64 opens to the portion of the runner-forming wall surface 60 on the upper mold 4 side of the entire circumference, connecting the runner 5 to the outside of the upper mold 4. The air vent 64 is provided between the upper mold body 62 and the shutter bush 61. More specifically, the air vent 64 is provided between the outer surface of the shutter bush 61 and the wall surface of the bush mounting hole 63 of the upper mold body 62.

[0025] The air vent 64 is provided on the cavity 6 side relative to the shutter 18. More specifically, as shown in Figure 8, a vent groove 65 is formed on the long side surface 61a of the outer surface of the shutter bush 61 on the cavity 6 side. The vent groove 65 extends to the tip surface of the shutter bush 61 on the runner 5 side. The air vent 64 is formed between the vent groove 65 and the wall surface of the bush mounting hole 63 of the upper mold body 62. The vent groove 65 is formed in an arc shape in cross-section. Therefore, the opening of the air vent 64 is approximately semicircular. Numerous vent grooves 65 are formed at regular intervals on the long side surface 61a of the shutter bush 61. Preferably, the vent grooves 65 are provided at regular intervals along the entire width of the runner 5 (the entire length in the short direction Y). On the long side surface 61a of the shutter bush 61, a flat surface 66 is provided between adjacent vent grooves 65. This flat surface 66 is a fitting surface. By securing flat surfaces 66 between the vent grooves 65 in this way, the shutter bush 61 can be fitted and mounted to the upper mold body 62 without any gaps. As shown in Figure 8(c), the vent groove 65 is formed linearly on the long side surface 61a of the shutter bush 61, along the direction in which the shutter bush 61 extends and retracts.

[0026] As described above, in the tilting gravity casting apparatus of this embodiment, by providing an air vent 64 near the shutter 18, gas accumulated near the shutter 18 can be efficiently discharged to the outside of the mold 2. Therefore, product quality can be improved. As shown in Figures 5 and 6, the mold 2 is in a vertical position, and in that state, the shutter 18 is located above the cavity 6. Therefore, gas tends to accumulate near the shutter 18, but since an air vent 64 is provided in that location, the gas accumulated near the shutter 18 can be efficiently discharged to the outside. Moreover, since the gas can be discharged from the air vent 64 using the pressing force when the shutter 18 closes, the gas can be discharged efficiently. Furthermore, after the shutter 18 closes the runner 5, the auxiliary pressure pin 53 protrudes and pressurizes the molten metal M in the runner 5. The auxiliary pressure pin 53 is located immediately on the cavity 6 side of the air vent 64. Therefore, gas can be discharged from the air vent 64 by the pressing force of the auxiliary pressure pin 53. In particular, since the protruding direction of the auxiliary pressure pin 53 is opposite to the protruding direction of the shutter 18, the gas remaining in the runner 5 can be efficiently sent to the air vent 64 and discharged to the outside of the upper mold 4. In addition, the pressure from the auxiliary pressure pin 53 pushes the gas in the runner 5 upward, forcing the gas to the air vent 64, which is located above the auxiliary pressure pin 53 in the vertical state shown in Figure 6.

[0027] Furthermore, since the air vent 64 is provided on the upper mold 4, which is the upper mold, gas can be efficiently discharged from the upper mold 4 side where gas tends to accumulate. Moreover, since the air vent 64 is formed between the upper mold body 62 and the shutter bush 61, the air vent 64 can be easily installed in a position right next to the shutter 18. Furthermore, since the vent groove 65 is formed on the shutter bush 61 side rather than the upper mold body 62 side, the air vent 64 can be easily created. In addition, by forming the vent groove 65 on the long side surface 61a of the shutter bush 61 on the cavity 6 side, the air vent 64 can be easily created. In this way, by forming the vent groove 65 on the shutter bush 61, the air vent 64 can be easily installed near the shutter 18, and gas near the shutter 18 can be efficiently discharged to the outside.

[0028] Furthermore, because the vent groove 65 has an arc shape in cross-section, the opening area of ​​the vent groove 65 can be easily secured. In addition, the opening area on both sides of the vent groove 65 can be easily widened, making it easy to remove burrs of molten metal M that have entered and solidified in the air vent 64, especially burrs that get caught on the side edges 64a of the opening of the air vent 64 and become difficult to remove. As a result, the maintainability of the mold 2 can be improved. [Explanation of Symbols]

[0029] 2 molds 3 Lower mold 4 Upper mold 5 Yudo 6 Cavity 7 Ladle 8 Base 9 Guide axis 10 Top Plate 11. First hydraulic cylinder 12. First Cylinder Rod 13 Movable Plate 14 Connecting members 15. Second hydraulic cylinder 16. Second Cylinder Rod 18 shutters 20 Third hydraulic cylinder 21 Third Cylinder Rod 23 Pressure pin 50. Fourth hydraulic cylinder 51. Fourth Cylinder Rod 53 Auxiliary pressure pin 60 Runway forming wall surface 61 Shutterbush 61a side 62 Upper body 63 bushing mounting holes 64 Air vents 64a Side edge 65 Bent groove 66 Plane section M molten metal

Claims

1. A tilting gravity casting apparatus in which molten metal is stored in the ladle of the mold and the mold is tilted to pour the molten metal into the mold cavity through the runner, The mold comprises an upper mold located on the upper side in the state before tilting, a lower mold located on the lower side in the state before tilting, and a shutter provided on the upper or lower mold that moves in and out from the runner-forming wall surface of the mold that forms the runner, in order to open and close the runner. A tilting gravity casting apparatus is provided in which the mold is equipped with an air vent that opens into the runner-forming wall near the cavity side of the shutter, and connects the runner to the outside of the mold.

2. The tilting gravity casting apparatus according to claim 1, wherein an air vent is provided in the upper mold.

3. The shutter is mounted on the upper mold, and the upper mold comprises an upper mold body and a rectangular tubular shutter bushing attached to the upper mold body to support the shutter's extension and retraction movement. The tilting gravity casting apparatus according to claim 2, wherein the air vent is provided between the upper mold body and the shutter bush by providing a vent groove on the outer surface of the shutter bush.

4. The tilting gravity casting apparatus according to claim 3, wherein the vent groove is arc-shaped in cross-section.

5. The tilting gravity casting apparatus according to any one of claims 1 to 4, wherein the mold is equipped with an auxiliary pressure pin for pressurizing the molten metal in the runner, and the auxiliary pressure pin pressurizes the molten metal in the runner after the shutter has blocked the runner.

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