Surge pressure suppression device and molding machine for molds

Abstract

The present invention provides a surge pressure suppression device for molds and a molding machine that can secure a larger volume of space for molten metal to flow through, which is generated by retracting a pin with the pressure of the molten metal. [Solution] This mold surge pressure suppression device 101 includes a blocking pin 2 whose tip surface 21 abuts against the inner surface 50 of the connecting channel 5 so as to block the connecting channel 5 that connects the overflow space 6 of the mold M and the cavity 4 that forms the molded product, and a pressurizing unit 3 that holds the blocking pin 2 so as to be able to move forward and backward and pressurizes the blocking pin 2 toward the inner surface 50 of the channel so as to maintain the state in which the blocking pin 2 is in contact with the inner surface 50 of the channel. The blocking pin 2 is configured to receive pressure from the molten metal while the molten metal is being filled into the mold M, retract against the pressure of the pressurizing unit 3, release the blocking of the connecting channel 5 and allow the molten metal to flow into the overflow space 6, thereby reducing the surge pressure generated when the molten metal is being filled.

Description

Technical Field

[0001] This invention relates to a surge pressure suppression device for a mold and a molding machine having a pin whose tip surface is located in a flow path of a mold through which molten metal flows.

Background Art

[0002] Conventionally, a die-casting machine having a pin whose tip surface is located in a flow path of a mold through which molten metal flows has been disclosed (for example, see Patent Document 1).

[0003] The above Patent Document 1 discloses a die-casting machine that includes a pin whose tip surface is located in a flow path of a mold through which molten metal flows, and by advancing the pin after completion of filling the mold with molten metal, locally pressurizes the molten metal to suppress the generation of casting cavities.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Although not explicitly stated in Patent Document 1 mentioned above, there is a conventional molding machine that reduces surge pressure, which is excessive pressure generated during filling, by retracting a pin whose tip surface abuts the flow path of the mold through the molten metal during filling using the pressure of the molten metal. Such a molding machine is configured to reduce surge pressure by generating a pressure loss (pressure drop) by flowing molten metal into the space between the pin tip before and after retraction. However, in such molding machines, due to constraints on the shape of the mold and the molding machine, it has not been possible to secure a sufficient volume of space for the molten metal to flow generated by retracting the pin, and therefore it has not been possible to sufficiently reduce surge pressure and sufficiently suppress the generation of burrs. For this reason, there is a need to secure a larger volume of space for the molten metal to flow generated by retracting the pin with the pressure of the molten metal.

[0006] This invention was made to solve the above-mentioned problems, and one objective of this invention is to provide a surge pressure suppression device for molds and a molding machine that can secure a larger volume of space for flowing molten metal, which is generated by retracting a pin with the pressure of the molten metal. [Means for solving the problem]

[0007] To achieve the above objective, the surge pressure suppression device for molds in the first aspect of this invention comprises a blocking pin whose tip surface abuts against the inner surface of a connecting channel so as to block a connecting channel that connects the overflow space of the mold and the cavity that forms the molded product, and a pressurizing unit that holds the blocking pin so as to be able to move forward and backward and pressurizes the blocking pin toward the inner surface of the channel so as to maintain the state in which the blocking pin is in contact with the inner surface of the channel, and the blocking pin is configured to reduce the surge pressure generated when molten metal is being filled into the mold by receiving pressure from the molten metal and retracting against the pressure of the pressurizing unit, thereby releasing the blocking of the connecting channel and allowing the molten metal to flow into the overflow space.

[0008] In the first aspect of this invention, the surge pressure suppression device for molds includes, as described above, a blocking pin that blocks a connecting channel connecting the overflow space and the cavity forming the molded product, and a pressurizing unit that pressurizes the blocking pin toward the inner surface of the channel. The blocking pin retracts against the pressure of the pressurizing unit in response to the pressure from the molten metal, releasing the blockage of the connecting channel and allowing molten metal to flow into the overflow space, thereby reducing the surge pressure. This differs from conventional configurations that reduce surge pressure by allowing molten metal to flow only in the space between the pin tip before and after retraction, as molten metal can also flow into the overflow space on the mold side. Therefore, in order to effectively reduce the surge pressure, a larger volume of space for molten metal to flow, generated by retracting the blocking pin with the pressure of the molten metal, can be secured. As a result, burrs generated on the mold can be effectively suppressed.

[0009] In the surge pressure suppression device for molds according to the first aspect described above, preferably, the pressurizing section is attached to the fixed mold, and the shut-off pin is pressed against the pressurizing section from the fixed mold side and contacts the inner surface of the flow path, which is part of the movable mold. With this configuration, the pressurizing section can be attached to the fixed mold, so it is possible to prevent the pressurizing section and its associated components from moving as the movable mold moves. In addition, since the pressurizing section can be attached to the fixed mold side, where there is ample space for placement, rather than the movable mold side, where space for placement is limited due to the provision of ejector pins and the like, a degree of freedom in the placement of the pressurizing section can be ensured.

[0010] In the mold surge pressure suppression device according to the first aspect described above, preferably, the tip surface of the shut-off pin that abuts the inner surface of the flow path includes a contact portion that abuts the inner surface of the flow path, a flow path opposing portion that faces the connecting flow path when the contact portion is in contact with the inner surface of the flow path, and an overflow opposing portion that faces the overflow space when the contact portion is in contact with the inner surface of the flow path. With this configuration, the connecting flow path can be shut off by the contact portion, the flow path opposing portion can receive the pressure of molten metal to retract the shut-off pin, and the overflow opposing portion can connect the connecting flow path and the overflow space on the front side of the overflow opposing portion after the shut-off pin has retracted.

[0011] In the mold surge pressure suppression device according to the first aspect described above, preferably, the pressurizing unit is a hydraulic cylinder that pressurizes the shut-off pin toward the inner surface of the flow path using hydraulic pressure, and the shut-off pin is configured to be detachably attached to the tip of the piston of the hydraulic cylinder. With this configuration, the hydraulic cylinder can apply a predetermined hydraulic pressure to the shut-off pin, making it easy to maintain the contact state of the tip of the shut-off pin with the inner surface of the flow path of the connecting flow path.

[0012] In this case, preferably, multiple shut-off pins are provided so as to be replaceable, and the multiple shut-off pins have different lengths from each other. By removing a shut-off pin from the tip of the piston of the hydraulic cylinder and replacing it with another shut-off pin of a different length, the retraction distance of the shut-off pin when filling the mold with molten metal can be adjusted. With this configuration, the retraction distance of the shut-off pin can be adjusted to bring the space into which the molten metal is poured closer to the optimal size.

[0013] In the mold surge pressure suppression device according to the first aspect described above, preferably, the insert having an overflow space for the mold is configured to be replaceable with another insert having an overflow space of a different volume. With this configuration, the volume of the overflow space can be adjusted on the mold side to bring the space into which the molten metal is poured closer to the optimal size.

[0014] In the surge pressure suppression device for molds according to the first aspect described above, preferably, the tip surface of the shut-off pin that contacts the inner surface of the flow path is formed by a circular flat surface, and when viewed from the direction of movement of the shut-off pin, the diameter of the tip surface is larger than the flow path width of the portion of the connecting flow path that connects to the shut-off pin. With this configuration, the connecting flow path can be easily shut off by a shut-off pin having a tip surface with a diameter larger than the flow path width of the portion of the connecting flow path that connects to the shut-off pin.

[0015] To achieve the above objective, the molding machine in the second aspect of this invention comprises a molding machine body and a mold surge pressure suppression device provided on a mold fixed to the molding machine body. The mold surge pressure suppression device comprises a blocking pin whose tip surface abuts against the inner surface of a connecting channel so as to block a connecting channel that connects the overflow space of the mold and the cavity that forms the molded product, and a pressurizing unit that holds the blocking pin so as to be able to move back and forth and pressurizes the blocking pin toward the inner surface of the channel so as to maintain the state in which the blocking pin is in contact with the inner surface of the channel. The blocking pin is configured to reduce the surge pressure generated when filling the mold by receiving pressure from the molten metal and retracting against the pressure of the pressurizing unit while the molten metal is being filled into the mold, thereby releasing the blocking of the connecting channel and allowing the molten metal to flow into the overflow space.

[0016] In the molding machine according to the second aspect of this invention, as described above, a blocking pin is provided that blocks a connecting channel that connects the overflow space and the cavity forming the molded product, and a pressurizing unit is provided that pressurizes the blocking pin toward the inner surface of the channel. The blocking pin retracts against the pressure of the pressurizing unit in response to the pressure from the molten metal, releasing the blocking of the connecting channel and allowing molten metal to flow into the overflow space, thereby reducing the surge pressure. This differs from the conventional configuration in which molten metal flows only into the space between the pin tip before and after retraction to reduce the surge pressure, and allows molten metal to flow into the overflow space on the mold side as well. Therefore, in order to effectively reduce the surge pressure, it is possible to provide a molding machine that can secure a larger volume of space for molten metal to flow, which is generated by retracting the pin (blocking pin) with the pressure of the molten metal. As a result, burrs generated on the mold can be effectively suppressed.

Advantages of the Invention

[0017] According to the present invention, as described above, it is possible to secure a larger volume of the space for flowing the molten metal generated by retreating the pin with the pressure of the molten metal.

Brief Description of the Drawings

[0018] [Figure 1] It is a diagram schematically showing the overall configuration of a molding machine provided with a surge pressure suppression device for a mold according to an embodiment of the present invention. [Figure 2] It is a diagram showing a movable mold provided with a connection flow path blocked by a shut-off pin and an overflow space of a surge pressure suppression device for a mold according to an embodiment of the present invention from the fixed mold side. [Figure 3] It is a cross-sectional view showing a surge pressure suppression device for a mold according to an embodiment of the present invention from the side. [Figure 4] It is a partially enlarged view of part A in FIG. 3. [Figure 5] It is a diagram for sequentially explaining the replacement of the shut-off pin of a surge pressure suppression device for a mold according to an embodiment of the present invention. [Figure 6] It is a diagram for sequentially explaining the retreating operation of the shut-off pin when filling the mold with molten metal of a surge pressure suppression device for a mold according to an embodiment of the present invention. [Figure 7] It is a cross-sectional view showing a surge pressure suppression device for a mold according to a modification of the present invention from the side.

Modes for Carrying Out the Invention

[0019] Hereinafter, an embodiment as an example of embodying the present invention will be described based on the drawings.

[0020] (Embodiment) Referring to FIGS. 1 to 6, a molding machine 100 provided with a surge pressure suppression device 101 for a mold according to an embodiment will be described.

[0021] The molding machine 100 is a die-casting machine. The molding machine 100 comprises a molding machine body 100a and a mold surge pressure suppression device 101 provided on the mold M fixed to the molding machine body 100a.

[0022] The molding machine body 100a is a horizontal device that moves the movable mold M2 in the horizontal direction. The molding machine body 100a includes a fixed die plate 10 to which a fixed mold M1 is fixed, a movable die plate 11 to which the movable mold M2 is fixed, a mold clamping device 12 that drives the movable die plate 11 to perform mold clamping and mold opening, an injection sleeve 13 having a pouring port 13a, a plunger 14, and an injection device (not shown) that moves the plunger 14 back and forth in the horizontal direction.

[0023] In each drawing, the vertical (up and down) direction is indicated by the Z direction, the upward direction is indicated by the Z1 direction, and the downward direction is indicated by the Z2 direction. The opening and closing direction of the movable mold M2 is indicated by the X direction, the open direction is indicated by the X1 direction, and the closed direction is indicated by the X2 direction. The X direction is the horizontal direction perpendicular to the Z direction, and is also the direction of movement of the shut-off pin 2, which will be described later. The horizontal direction perpendicular to both the X and Z directions is indicated by the Y direction.

[0024] (Configuration of a surge pressure suppression device for molds) The mold surge pressure suppression device 101 shown in Figure 1 is a device for suppressing surge pressure. More specifically, the mold surge pressure suppression device 101 is a device for reducing the surge pressure generated when molten metal is filled into the mold. Surge pressure is the excessive pressure (mold opening force) inside the mold M that occurs in the pressure-boosting process, which is the final stage when filling the mold M with molten metal, and is a cause of burr formation on the dividing surface M3 between the fixed mold M1 and the movable mold M2. The mold surge pressure suppression device 101 is configured to mitigate the increase in pressure of the molten metal by providing a space for the molten metal to escape when the pressure inside the mold M increases as the molten metal is filled into the mold. In other words, the mold surge pressure suppression device 101 is configured to generate a pressure loss for the molten metal that is filled into the mold M at high pressure.

[0025] The mold surge pressure suppression device 101 comprises a shut-off pin 2 and a pressurizing unit 3. Before describing each component of the mold surge pressure suppression device 101, the mold M in which the mold surge pressure suppression device 101 is installed will be described first.

[0026] As shown in Figures 1 and 2, the mold M is configured to supply molten metal so that it is pushed upward from the lower side of the cavity 4 where the molded product is formed. The injection sleeve 13 is fixed to the fixed mold M1. A connecting channel 5 is provided at the top of the cavity 4. The connecting channel 5 connects the overflow space 6 of the mold M to the cavity 4. The connecting channel 5 also functions as a venting runner. The mold M suppresses the occurrence of casting defects in the cavity 4 by flowing and filling not only the cavity 4 but also the connecting channel 5, which is a venting runner. The connecting channel 5 is a concave channel formed so as to be recessed in the X1 direction from the dividing surface M3.

[0027] Viewed from the opening and closing direction (X direction) of the movable mold M2, a gas vent M4 is provided in the upper part of the connecting channel 5 near the center in the Y direction. The gas vent M4 extends along the dividing surface M3 and is configured to discharge only gas to the outside of the mold M without allowing molten metal to pass through.

[0028] Viewed from the opening and closing direction (X direction) of the movable mold M2, there is one overflow space 6 at each end (two in total) of the upper part of the Y direction of the connecting channel 5. The overflow space 6 is a concave space formed so as to be recessed in the X1 direction from the dividing surface M3.

[0029] As shown in Figure 3, the overflow space 6 is provided in an insert 60 that is detachable from the main body of the movable mold M2. That is, the insert 60 has the overflow space 6 of the mold M. The mold M (mold surge pressure suppression device 101) is configured so that this insert 60 can be replaced with other inserts 60a having overflow spaces 6a of different volumes.

[0030] As shown in Figures 2 and 3, a channel inner surface 50, which is part of the movable mold M2 and located on the dividing surface M3, is provided between the overflow space 6 and the concave portion of the connecting channel 5. The channel inner surface 50 is a flat surface that separates the overflow space 6 and the concave portion of the connecting channel 5, and also contacts the tip surface 21 of the shut-off pin 2. The channel inner surface 50 is the surface that forms part of the connecting channel 5 when the shut-off pin 2 retracts. When the shut-off pin 2 retracts from a state in which the channel inner surface 50 and the shut-off pin 2 are in contact, a space is formed by the three surfaces: the channel inner surface 50, the tip surface 21 of the shut-off pin 2, and the inner circumferential surface of the through hole M10 in which the shut-off pin 2 is positioned, creating a pin tip side space 20 (see Figure 6) into which molten metal flows. The pin tip side space 20 is connected to the overflow space 6 from below. The pin tip side space 20 has the function of injecting molten metal to suppress surge pressure and the function of being a connecting channel 5 that flows molten metal into the overflow space 6.

[0031] The through-hole M10 in which the shut-off pin 2 is located is formed to extend in the X2 direction from the dividing surface M3 of the fixed mold M1. A recess M11 is provided on the end face of the fixed mold M1 in the X2 direction, recessed in the X1 direction. The recess M11 is a space for arranging the pressurizing section 3 and is in communication with the X2 end of the through-hole M10. The pin tip side space 20 (see Figure 6) is the space on the X1 direction side of the tip surface 21 of the shut-off pin 2 and functions as part of the connecting channel 5. The overflow space 6 and the cavity 4 are connected via the pin tip side space 20 (connecting channel 5).

[0032] As shown in Figure 2, when viewed from the opening and closing direction (X direction) of the movable mold M2, one mold surge pressure suppression device 101 (two in total) is provided at the upper part of both ends in the Y direction of the connecting channel 5, which is a runner for gas release. The mold surge pressure suppression device 101 is provided at the end of the connecting channel 5 on the overflow space 6 side. The mold surge pressure suppression device 101 is located at the boundary between the connecting channel 5 and the overflow space 6. Since the two mold surge pressure suppression devices 101 have similar configurations, the configuration of one mold surge pressure suppression device 101 will be described below.

[0033] (Configuration of the shut-off pin in a surge pressure suppression device for molds) As shown in Figures 3 and 4, the blocking pin 2 is configured such that its tip surface 21 abuts against the inner surface 50 of the connecting channel 5 (part of the movable mold M2) of the connecting channel 5, which connects the overflow space 6 of the mold M and the cavity 4 (see Figure 2) that forms the molded product. In one example, the blocking pin 2 is formed from a round metal rod extending in the X direction. The blocking pin may also be formed from a rectangular or triangular rod. The blocking pin 2 is fitted into the through hole M10 of the fixed mold M1 and is configured to move back and forth in the X direction inside the through hole M10. The gap between the through hole M10 and the fixed mold M1 is large enough to prevent molten metal from entering.

[0034] The shut-off pin 2 is configured to be detachably attached to the tip of the piston 30 of the pressurizing unit 3 (hydraulic cylinder), which will be described later. Specifically, the end of the shut-off pin 2 in the X2 direction is provided with a connecting portion 22 for connecting to the piston 30 of the pressurizing unit 3. For example, the connecting portion 22 is formed by a lateral T-shaped protrusion projecting in the X2 direction. The piston 30 of the pressurizing unit 3 is also provided with a connecting portion 30a for connecting to the connecting portion 22. For example, the connecting portion 30a is formed by a lateral T-shaped recess recessing in the X2 direction. The shut-off pin 2 and the piston 30 are connected to each other by engaging the connecting portion 22 and the connecting portion 30a. When the shut-off pin 2 and the piston 30 are positioned in the through hole M10 extending in the X direction, the connection between the shut-off pin 2 and the piston 30 is not released by the shut-off pin 2 moving in the X direction.

[0035] The mold surge pressure suppression device 101 (pressurizing unit 3) is attached to the fixed mold M1. The shut-off pin 2 is pressurized by the pressurizing unit 3 from the fixed mold M1 side and is configured to contact the inner surface 50 of the flow path, which is part of the movable mold M2 (connecting flow path 5). The shut-off pin 2 is constantly pressurized by the pressurizing unit 3 from the fixed mold M1 side toward the movable mold M2 side (X1 direction side). That is, the shut-off pin 2 is pressed against the movable mold M2 from the fixed mold M1 side before the molten metal is filled into the mold M. The shut-off pin 2 is configured to receive pressure from the molten metal during the filling of the mold M, retract (move in the X2 direction) against the pressure of the pressurizing unit 3, release the shut-off of the connecting flow path 5, and allow the molten metal to flow into the overflow space 6, thereby reducing the surge pressure generated when the molten metal is filled. Details of the configuration for retracting the shut-off pin 2 will be described later.

[0036] As shown in Figure 2, the tip surface 21 of the shut-off pin 2 that contacts the inner surface 50 of the flow path is formed by a circular, flat surface. As an example, when viewed from the direction of movement of the shut-off pin 2 (X direction), the diameter of the tip surface 21 (through hole M10) is larger than the width of the flow path in the portion of the connecting flow path 5 that connects to the shut-off pin 2 (pin tip side space 20).

[0037] As shown in Figure 4, the tip surface 21 of the shut-off pin 2 that contacts the inner surface 50 of the flow path of the movable mold M2 includes a contact portion 210, a flow path opposing portion 211, and an overflow opposing portion 212.

[0038] The contact portion 210 of the shut-off pin 2 is the portion that contacts the inner surface 50 of the flow path. The flow path-facing portion 211 of the shut-off pin 2 is the portion that faces the connecting flow path 5 when the contact portion 210 is in contact with the inner surface 50 of the flow path, and is located below the contact portion 210 (towards the Z2 direction). The overflow-facing portion 212 of the shut-off pin 2 is the portion that faces the overflow space 6 when the contact portion 210 is in contact with the inner surface 50 of the flow path, and is located above the contact portion 210 (towards the Z1 direction). The entire outer surface of the shut-off pin 2 is always facing the inner surface of the through hole M10 of the fixed mold M1.

[0039] As shown in Figure 6, when the contact portion 210 of the shut-off pin 2 receives pressure from the molten metal and the shut-off pin 2 retracts and moves away from the inner surface 50 of the flow path of the movable mold M2, a space 20 on the pin tip side is formed between the contact portion 210 and the inner surface 50 of the flow path. As the shut-off pin 2 retracts in the X2 direction, the volume of the space 20 on the pin tip side increases. The volume of the space 20 on the pin tip side reaches its maximum when the shut-off pin 2 contacts the end face 311a on the X2 direction side of the rear oil chamber 311 of the pressurizing section 3, which will be described later.

[0040] As shown in Figure 5, multiple shut-off pins 2 and 2a are provided so that they can be replaced. The multiple shut-off pins 2 and 2a have different lengths in the X direction. By removing the shut-off pin 2 from the tip of the piston 30, which is the pressurizing part 3 (described later), and replacing it with another shut-off pin 2a of a different length, the retraction distance of the shut-off pin 2 when filling the mold M with molten metal can be adjusted. The retraction distance is the distance from the pressure-receiving surface 30b of the piston 30 to the end surface 311a of the rear oil chamber 311 on the X2 direction side when the tip surface 21 of the shut-off pin 2 is in contact with the inner surface 50 of the flow path (movable mold M2).

[0041] In the example shown in Figure 5, the shut-off pin 2 is replaced with another shut-off pin 2a that is longer by L. As a result, the retraction distance D1 changes to a smaller retraction distance D2 (= D1 - L). Note that this is not limited to the example shown in Figure 5; it is also possible to increase the retraction distance by replacing the shut-off pin 2 with one of a smaller length.

[0042] (Configuration of the pressurizing section of a surge pressure suppression device for molds) As shown in Figure 6, the pressurizing unit 3 is configured to hold the shut-off pin 2 so that it can move back and forth, and to pressurize the shut-off pin 2 toward the inner surface 50 of the flow path so that the shut-off pin 2 is in contact with the inner surface 50 of the flow path. In short, the pressurizing unit 3 is configured to bias the shut-off pin 2 from the fixed mold M1 side toward the movable mold M2 side, thereby pressing the shut-off pin 2 against the movable mold M2. The pressurizing unit 3 maintains the contact state of the shut-off pin 2 with the movable mold M2 (inner surface 50 of the flow path). The pressurizing unit 3 is located inside the recess M11 and is detachably fixed to the inner surface of the recess M11 by a fixing member B such as a bolt.

[0043] The pressurizing section 3 is a hydraulic cylinder that uses hydraulic pressure to pressurize the shut-off pin 2 toward the inner surface 50 of the flow path. The piston 30 of the pressurizing section 3, which is a hydraulic cylinder, divides the inside of the cylinder tube 31 into a front oil chamber 310 on the X1 direction side (front side) and a rear oil chamber 311 on the X2 direction side (rear side). The pressurizing section 3 is provided with a pressurizing source 33 (see Figure 1) that pressurizes the rear oil chamber 311 via piping 32. In addition, piping 34 for adjusting the amount of oil is also connected to the front oil chamber 310. The pressurizing source 33 is configured to supply hydraulic fluid to the rear oil chamber 311 to pressurize (bias) the shut-off pin 2 in the X1 direction. As an example, the pressurizing source 33 is composed of an accumulator. Alternatively, the pressurizing section may be composed of a biasing member that pressurizes (biasses) the shut-off pin by elastic deformation, without a pressurizing source.

[0044] (Regarding the retraction of the shut-off pin) The retraction of the shut-off pin 2 will be explained with reference to Figure 6.

[0045] Before molten metal filling, the shut-off pin 2 connected to the piston 30 is pressurized in the X1 direction by the pressurizing unit 3 together with the piston 30 and pressed against the inner surface of the flow path 50 (movable mold M2). In other words, the shut-off pin 2 is held in contact with the inner surface of the flow path 50.

[0046] Subsequently, when the filling of molten metal into the mold M begins, the molten metal reaches the flow path opposing portion 211 of the tip surface 21 of the shut-off pin 2, and the flow path opposing portion 211 is pressurized in the X2 direction from the molten metal. The force F1 in the X2 direction applied to the shut-off pin 2 and piston 30 from the molten metal is obtained by "area of ​​flow path opposing portion 211 × pressure of molten metal". The force F2 in the X1 direction applied to the shut-off pin 2 and piston 30 from the pressurizing section 3 is obtained by "area of ​​pressure-receiving surface 30b of piston 30 (end face on the X1 direction side of the rear oil chamber 311) × pressure of the hydraulic fluid in the rear oil chamber 311".

[0047] In the initial stages of filling the mold M with molten metal, the pressure of the molten metal inside the mold M is relatively low, resulting in the condition "force F1 in the X1 direction ≤ force F2 in the X2 direction". In this case, a force of magnitude "force F2 - force F1" acting on the shut-off pin 2 in the X1 direction (the leftward force in Figure 6) maintains contact between the shut-off pin 2 and the inner surface 50 of the flow path. That is, the shut-off state of the connecting flow path 5 by the shut-off pin 2 is maintained.

[0048] Subsequently, during the pressure-boosting process, which is the final stage in filling the mold M with molten metal, the pressure of the molten metal inside the mold M increases, and the state changes to "force F1 in the X1 direction > force F2 in the X2 direction". As a result, a force acting on the shut-off pin 2 in the X2 direction (a force directed to the right in Figure 6) is generated, causing the shut-off pin 2 to begin retracting in the X2 direction. Consequently, the shut-off pin 2 separates from the inner surface 50 of the flow path, and the shut-off of the connecting flow path 5 by the shut-off pin 2 is released. When the shut-off of the connecting flow path 5 by the shut-off pin 2 is released, molten metal flows into the two spaces, the pin tip side space 20 and the overflow space 6, suppressing surge pressure that would generate burrs on the dividing surface M3.

[0049] (Effects of the embodiment) The effects of this embodiment will be described.

[0050] In this embodiment, as described above, the device includes a shut-off pin 2 that shuts off a connecting channel 5 connecting the overflow space 6 and the cavity 4 that forms the molded product, and a pressurizing unit 3 that pressurizes the shut-off pin 2 toward the inner surface 50 of the channel. The shut-off pin 2 retracts against the pressure of the pressurizing unit 3 in response to the pressure from the molten metal, releasing the shut-off of the connecting channel 5 and allowing the molten metal to flow into the overflow space 6, thereby reducing the surge pressure. This differs from conventional configurations where molten metal is only allowed to flow into the space between the pin tip before and after retraction to reduce the surge pressure, allowing molten metal to flow into the overflow space 6 on the mold M side as well. Therefore, in order to effectively reduce the surge pressure, a larger volume of space for molten metal to flow (the space formed by the overflow space 6 and the pin tip side space 20) can be secured by retracting the shut-off pin 2 with the pressure of the molten metal. As a result, burrs generated on the mold M can be effectively suppressed.

[0051] In this embodiment, as described above, the pressurizing unit 3 is attached to the fixed mold M1, and the shut-off pin 2 is pressurized by the pressurizing unit 3 from the fixed mold M1 side and is configured to contact the inner surface 50 of the flow path, which is part of the movable mold M2. This allows the pressurizing unit 3 to be attached to the fixed mold M1, thus preventing the pressurizing unit 3 and its associated components (such as the piping 32) from moving as the movable mold M2 moves. Furthermore, since the pressurizing unit 3 can be attached to the fixed mold M1 side, which has ample space for placement, rather than the movable mold M2 side, which has limited space for placement due to the presence of ejector pins and the like, a degree of freedom in the placement of the pressurizing unit 3 can be ensured.

[0052] In this embodiment, as described above, the tip surface 21 of the shut-off pin 2 that abuts the inner surface 50 of the flow path includes a contact portion 210 that abuts the inner surface 50 of the flow path, a flow path opposing portion 211 that faces the connecting flow path 5 when the contact portion 210 is in contact with the inner surface 50 of the flow path, and an overflow opposing portion 212 that faces the overflow space 6 when the contact portion 210 is in contact with the inner surface 50 of the flow path. As a result, the contact portion 210 can shut off the connecting flow path 5, the flow path opposing portion 211 can receive the pressure of the molten metal to retract the shut-off pin 2, and the overflow opposing portion 212 can connect the connecting flow path 5 and the overflow space 6 on the front side of the overflow opposing portion 212 after the shut-off pin 2 has retracted.

[0053] In this embodiment, as described above, the pressurizing unit 3 is a hydraulic cylinder that pressurizes the shut-off pin 2 toward the inner surface 50 of the flow path using hydraulic pressure, and the shut-off pin 2 is configured to be detachably attached to the tip of the piston 30 of the hydraulic cylinder. This makes it possible to easily maintain the contact state of the tip of the shut-off pin 2 with the inner surface 50 of the flow path of the connecting flow path 5 by applying a predetermined hydraulic pressure to the shut-off pin 2 using the hydraulic cylinder.

[0054] In this embodiment, as described above, multiple shut-off pins 2 are provided so as to be replaceable, and the multiple shut-off pins 2 have different lengths from each other. By removing a shut-off pin 2 from the tip of the piston 30 of the hydraulic cylinder and replacing it with another shut-off pin 2 of a different length, the retraction distances D1 and D2 of the shut-off pins 2 when filling the mold M can be adjusted. This makes it possible to adjust the retraction distances D1 and D2 of the shut-off pins 2 to bring the space into which the molten metal is poured closer to the optimal size.

[0055] In this embodiment, as described above, the insert 60 having an overflow space 6 in the mold M is configured to be replaceable with other inserts 60a having overflow spaces 6 of different volumes. This allows the volume of the overflow space 6 to be adjusted on the mold M side, bringing the space into which the molten metal is poured closer to the optimal size.

[0056] In this embodiment, as described above, the tip surface 21 of the shut-off pin 2 that contacts the inner surface 50 of the flow path is formed by a circular flat surface, and when viewed from the direction of movement of the shut-off pin 2, the diameter of the tip surface is larger than the flow path width of the portion of the connecting flow path 5 that connects to the shut-off pin 2. As a result, the connecting flow path 5 can be easily shut off by the shut-off pin 2 having a tip surface 21 with a diameter larger than the flow path width of the portion of the connecting flow path 5 that connects to the shut-off pin 2.

[0057] [Differentiation] It should be noted that the embodiments disclosed herein are illustrative and not restrictive in all respects. The scope of the present invention is indicated by the claims rather than by the description of the embodiments above, and further includes all modifications within the meaning and scope equivalent to the claims.

[0058] For example, the above embodiment shows an example in which a mold surge pressure suppression device is provided on a fixed mold, but the present invention is not limited to this. In the present invention, a mold surge pressure suppression device may be provided on a movable mold.

[0059] In the above embodiment, an example was shown in which two mold surge pressure suppression devices were provided for the mold, but the present invention is not limited to this. In the present invention, a number of mold surge pressure suppression devices other than two may be provided for the mold.

[0060] In the above embodiment, an example was shown in which the mold surge pressure suppression device is arranged at both ends in the width direction (Y direction) of the mold connection channel, but the present invention is not limited to this. In the present invention, the mold surge pressure suppression device may be arranged at an intermediate position in the width direction of the mold connection channel, etc.

[0061] In the above embodiment, an example was shown in which the mold surge pressure suppression device is positioned above the cavity, but the present invention is not limited to this. In the present invention, the mold surge pressure suppression device may be positioned at the same height as the cavity, or below the cavity.

[0062] In the above embodiment, an example was shown in which the pressurizing section that pressurizes the shut-off pin is configured with a hydraulic cylinder, but the present invention is not limited thereto. In the present invention, the pressurizing section that pressurizes the shut-off pin may be configured with an elastic member, a device that generates pressure by electric power or magnetic force, or the like.

[0063] In the above embodiment, an example was shown in which the tip surface of the shut-off pin has three parts: a "contact portion," a "flow path opposing portion," and an "overflow opposing portion." However, the present invention is not limited to this. In the present invention, as shown in the modified example in Figure 7, the tip surface 21a of the shut-off pin may have a "contact portion 210" and a "flow path opposing portion 211," but may not have an "overflow opposing portion." In this case, a notch M10a is provided at the tip of the through hole M10 in order to allow molten metal to flow into the overflow space 6.

[0064] In the above embodiment, an example was shown in which the overflow space is provided in a nested manner, but the present invention is not limited thereto. In the present invention, the overflow space may be provided in the movable mold body.

[0065] In the above embodiment, an example was shown in which a surge pressure suppression device for a mold is configured such that the shut-off pin moves in the opening and closing direction of the mold. However, the present invention is not limited to this. In the present invention, the surge pressure suppression device for a mold may be configured such that the shut-off pin moves in a direction intersecting the opening and closing direction of the mold.

[0066] In the above embodiment, an example was shown in which the tip surface of the shut-off pin was formed as a flat surface, but the present invention is not limited thereto. In the present invention, the tip surface of the shut-off pin may be formed as an inclined surface or a curved surface.

[0067] In the above embodiment, an example was shown in which the gas vent is provided in the connecting passage which is a runner for gas removal, but the present invention is not limited to this. In the present invention, the gas vent may be provided in the overflow space.

[0068] In the above embodiment, an example was shown in which an overflow space is provided in the mold on the side of the fixed mold and the movable mold that is different from the mold on which the mold surge pressure suppression device is attached. However, the present invention is not limited to this. In the present invention, an overflow space may be provided in the mold on the same side of the fixed mold and the movable mold that is the same as the mold on which the mold surge pressure suppression device is attached.

[0069] In the above embodiment, an example was shown in which a mold surge pressure suppression device was provided for all overflow spaces, but the present invention is not limited thereto. In the present invention, a mold surge pressure suppression device may be provided for only some of the overflow spaces.

[0070] In the above embodiment, an example was shown in which the connecting portion of the shut-off pin is a convex portion and the connecting portion of the piston is a concave portion, but the present invention is not limited to this. In the present invention, the connecting portion of the shut-off pin may be a concave portion and the connecting portion of the piston may be a convex portion. [Explanation of Symbols]

[0071] 2. Shut-off pins 3 Pressurized section 4 Cavities 5 Connection channel 6. Overflow space 20 Pin tip side space 21, 21a (Tip surface of the shut-off pin) 30 pistons 50 (Inner surface of the connecting channel) 60 nesting 60a Other nesting 100 molding machine 100a Molding machine body 101 Surge pressure suppression device for molds 210 Contact portion (of the tip surface of the shut-off pin) 211 (The part of the tip of the shut-off pin) that faces the flow path 212 Overflow-facing portion (of the tip surface of the shut-off pin) D1, D2 Retraction distance M mold M1 Fixed mold M2 movable mold

Claims

1. A blocking pin whose tip surface abuts against the inner surface of the connecting channel so as to block the connecting channel that connects the overflow space of the mold and the cavity that forms the molded product, The system includes a pressurizing unit that holds the shut-off pin so that it can move forward and backward, and pressurizes the shut-off pin toward the inner surface of the flow path so as to maintain the state in which the shut-off pin is in contact with the inner surface of the flow path, A surge pressure suppression device for a mold, wherein the shut-off pin is configured to receive pressure from the molten metal while the molten metal is being filled into the mold, retract against the pressure of the pressurizing section, release the shut-off of the connecting channel, and allow the molten metal to flow into the overflow space, thereby reducing the surge pressure generated when the molten metal is being filled.

2. The pressurizing section is attached to the fixed mold, The surge pressure suppression device for a mold according to claim 1, wherein the shut-off pin is pressurized from the fixed mold side to the pressurizing section and is configured to contact the inner surface of the flow path, which is part of the movable mold.

3. The tip surface of the shut-off pin that contacts the inner surface of the flow path is A contact portion that contacts the inner surface of the flow path, With the aforementioned contact portion in contact with the inner surface of the flow path, the flow path opposing portion faces the connecting flow path, The surge pressure suppression device for a mold according to claim 1, further comprising an overflow facing portion that faces the overflow space while the contact portion is in contact with the inner surface of the flow path.

4. The pressurizing section is a hydraulic cylinder that pressurizes the shut-off pin toward the inner surface of the flow path using hydraulic pressure, The surge pressure suppression device for molds according to claim 1, wherein the shut-off pin is configured to be detachably attached to the tip of the piston of the hydraulic cylinder.

5. Multiple shut-off pins are provided so as to be replaceable. The multiple blocking pins have different lengths from each other. A surge pressure suppression device for a mold according to claim 4, wherein the device is configured to allow adjustment of the retraction distance of the shut-off pin when filling the mold with molten metal, by removing the shut-off pin from the tip of the piston of the hydraulic cylinder and replacing it with another shut-off pin of a different length.

6. A surge pressure suppression device for a mold according to claim 1, wherein the insert having the overflow space of the mold is configured to be replaceable with another insert having the overflow space of a different volume.

7. The tip surface of the shut-off pin that contacts the inner surface of the flow path is formed by a circular, flat surface. The surge pressure suppression device for a mold according to claim 1, wherein, viewed from the direction of movement of the shut-off pin, the diameter of the tip surface is greater than the width of the flow path in the portion of the connecting flow path connected to the shut-off pin.

8. The molding machine body and The system includes a mold surge pressure suppression device provided on the mold fixed to the molding machine body, The aforementioned surge pressure suppression device for molds is A blocking pin is provided, the tip of which contacts the inner surface of the connecting channel of the connecting channel, so as to block the connecting channel that connects the overflow space of the mold and the cavity that forms the molded product. The system includes a pressurizing unit that holds the shut-off pin so that it can move forward and backward, and pressurizes the shut-off pin toward the inner surface of the flow path so as to maintain the state in which the shut-off pin is in contact with the inner surface of the flow path, A molding machine wherein the shut-off pin is configured to retract against the pressure of the pressurizing section in response to pressure from the molten metal while the molten metal is being filled into the mold, thereby releasing the shut-off of the connecting channel and allowing the molten metal to flow into the overflow space, thereby reducing the surge pressure generated when the molten metal is being filled.

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