Piston gating system, piston casting mold and inner gate cooling method thereof

Abstract

The application discloses a piston runner system, a piston casting mold and an inner gate cooling method thereof. The piston runner system comprises a straight runner, a cross runner, a transition section and a connecting section. One end of the transition section is connected with the straight runner, the other end is connected with the connecting section, and one end of the connecting section away from the transition section is connected with an inner gate. The transition section extends in an arc shape, and the cross-sectional area of the transition section gradually decreases from the side close to the straight runner to the side close to the connecting section. The width of the connecting section gradually decreases from the side close to the cross runner to the other side, and the upper and lower sides of the connecting section are respectively provided with an upper taper surface and a lower taper surface. The distance between the upper taper surface and the lower taper surface gradually increases from the side close to the connecting section to the other side. The inner gate is provided. The piston runner system provided by the application avoids the turbulent flow of the metal liquid in the runner system, thereby eliminating the air entrapment and secondary oxidation slag inclusion defects of the piston blank, and improving the casting quality of the piston blank.

Description

Technical Field

[0001] This invention relates to the field of piston casting equipment, and in particular to a piston runner system. Furthermore, this invention also relates to a piston casting mold including the above-described piston runner system and a method for cooling its inner gate. Background Technology

[0002] Aluminum alloy pistons are formed into piston blanks through piston casting molds, and then the piston blanks are processed into finished pistons. Because pistons operate under harsh environments of high temperature, high pressure, and high speed in engines for extended periods, the piston matrix must possess excellent mechanical properties. The internal density of the piston matrix is ​​a key factor affecting its mechanical properties. Defects such as porosity, air entrapment, and slag inclusions within the piston matrix will severely reduce its mechanical properties, thereby significantly shortening its service life. The internal density of the piston matrix is ​​determined during the casting process of the piston blank. During the casting of the piston blank, the gating system is a crucial factor affecting its internal density. An inadequate gating system can lead to turbulence and poor feeding during the pouring of molten aluminum, resulting in casting defects such as porosity, air entrapment, and slag inclusions within the piston blank, making the piston matrix structure less dense.

[0003] In existing technology, piston casting systems consist of a sprue, a runner, and an ingate, such as... Figure 1 As shown in the diagram, the sprue is the crucial link between the sprue and the ingate. The sprue must efficiently redirect the molten aluminum from the sprue to the ingate. Simultaneously, the solidification time of the molten aluminum in the sprue must be later than that in the ingate. This allows the sprue to compensate for the solidification and shrinkage of the ingate, eliminating porosity in the piston blank near the ingate. Therefore, the sprue is the most critical component of the casting system and a core structural element of its design.

[0004] However, in existing piston casting systems, the straight-line design of the runner prevents the molten aluminum from smoothly transitioning to the ingate when poured from the sprue. This leads to turbulence and air entrapment in the runner, resulting in defects such as air entrapment and slag inclusions in the piston blank. Furthermore, existing technology requires an insulating coating to ensure the molten aluminum in the runner solidifies later than in the ingate, thus providing solidification compensation. However, in actual production, vibrations during mold opening and closing, the mismatch in expansion coefficients between the mold and the coating, and the coating's tendency to detach, cause the coating on the runner to peel off. Once the coating peels off, the runner loses its solidification compensation function for the ingate, resulting in a porous piston blank.

[0005] Therefore, how to improve the casting quality of piston blanks is a technical problem that needs to be solved by those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to provide a piston gating system that effectively avoids casting defects such as porosity, air entrapment, and slag inclusions in piston blanks, thereby improving the quality of the piston blanks. Another purpose of this invention is to provide a piston casting mold including the above-mentioned piston gating system and a method for cooling its inlet gate.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A piston gating system, comprising:

[0009] A sprue is used to supply molten metal into the runner;

[0010] A horizontal sprue transitions from the sprue to the ingate. The horizontal sprue includes a transition section and a connecting section. One end of the transition section connects to the sprue, and the other end connects to the connecting section. The end of the connecting section furthest from the transition section connects to the ingate. The transition section extends in an arc shape, and its cross-sectional area gradually decreases from the side closer to the sprue to the side closer to the connecting section. The width of the connecting section gradually decreases from the side closer to the horizontal sprue to the other side, and the upper and lower sides of the connecting section are respectively provided with an upper conical surface and a lower conical surface. The distance between the upper and lower conical surfaces gradually increases from the side closer to the connecting section to the other side.

[0011] The ingate is used to connect the runner and the cavity.

[0012] Preferably, the cast-in-place channel is provided with a plurality of slag-hanging grooves, the extension direction of the slag-hanging grooves being perpendicular to the extension direction of the cast-in-place channel, and the slag-hanging grooves being arranged along the extension direction of the cast-in-place channel.

[0013] Preferably, the width of the slag-hanging trough is d, the depth is (0.5-1)d, and the spacing between adjacent slag-hanging troughs is (2-3)d of the width.

[0014] Preferably, the thickness of the lower end of the skirt of the piston blank is A, the downward slope of the lower conical surface is B, B is 20-30°, and the upward slope of the upper conical surface is C, C is 25-35°.

[0015] Preferably, the height D of the transition section in the horizontal runner is (2.5-4)A; the angle between the connecting section of the horizontal runner and the center line of the cavity is F, F = 15-25°; the maximum distance between the horizontal runner and the center line of the cavity is G, G = (0.8-1.1)E; the maximum thickness of the horizontal runner is H, H = (0.7-1)D; the arc value of the outer side of the transition section of the horizontal runner is RI, RI = 20-30mm; and the arc value of the inner side of the transition section of the horizontal runner is RJ, RJ = 5-10mm.

[0016] Preferably, the ingate is provided with an ingate, the width of which is E, and E equals (0.7-1)A; the width of the sprue is K, and K = (3-4)E; the distance between the sprue and the ingate is L, and L = (0.5-0.7) times the radius of the piston blank; the minimum depth of the sprue is M, and M = (0.5-0.7)K; the upward opening slope of the sprue is N, and N = 2-3°.

[0017] A piston casting mold includes a mold body and the aforementioned piston runner system disposed within the mold body.

[0018] Preferably, cooling channels are provided on the left and right sides of the inner gate of the mold body near the piston runner system, and the cooling channels are used for the circulation of cooling medium.

[0019] Preferably, the mold body includes an inner mold and an outer mold, the cooling channel is formed on the outer mold, the diameter of the cooling channel is 6-8mm, the distance of the cooling channel from the upper horizontal runner of the outer mold is T, T = 4-6mm, the distance of the cooling channel from the cavity of the outer mold is U, U = 4-6mm; the cooling channel includes an interface channel and a channel body located inside the outer mold, the outer side of the interface channel is provided with inlet and outlet ports, and the angle between the interface channel and the center line of the outer mold is S, S = 35-55°.

[0020] A method for cooling the gate inside a piston casting mold, applied to the aforementioned piston casting mold, includes the following steps:

[0021] Step S1: After the molten metal is poured, a cooling medium is introduced into the cooling channel at a flow rate of 3-6 liters / minute.

[0022] Step S2: Control the flow time of the cooling medium to 30-50% of the total solidification time of the piston blank.

[0023] The piston gating system provided by this invention includes: a sprue for supplying molten metal into a runner; a runner that transitions from the sprue to the ingate, the runner including a transition section and a connecting section, one end of the transition section being connected to the sprue and the other end being connected to the connecting section, the end of the connecting section away from the transition section being connected to the ingate; the transition section extending in an arc shape, and the cross-sectional area of ​​the transition section gradually decreasing from the side closer to the sprue to the side closer to the connecting section; the width of the connecting section gradually decreasing from the side closer to the runner to the other side, and the upper and lower sides of the connecting section respectively having an upper conical surface and a lower conical surface, the distance between the upper conical surface and the lower conical surface gradually increasing from the side closer to the connecting section to the other side; and an ingate for connecting the runner and the cavity. The piston gating system provided by this invention utilizes the arc-shaped bend and gradually changing cross-section structure of the transition section in the horizontal gating, as well as the upper and lower conical gradually changing structure of the connecting section, to smoothly transition the molten metal in the sprue to the ingate, avoiding turbulence in the molten metal in the gating system, thereby eliminating air entrapment and secondary oxidation slag inclusion defects in the piston blank and improving the casting quality of the piston blank.

[0024] The piston casting mold provided by this invention includes a mold body and a piston gating system disposed within the mold body, wherein the piston gating system is the aforementioned piston gating system; and cooling channels are provided on the left and right sides of the ingate near the piston gating system within the mold body, the cooling channels being used for the flow of cooling medium. With the piston casting mold provided by this invention, after the molten metal is poured, cooling medium is rapidly introduced into the cooling channels to lower the temperature of the mold near the ingate. Because the cooling channels are close to the molten metal in the ingate, the molten metal in the ingate can be cooled quickly, thereby achieving the effect that the molten metal in the ingate solidifies before the molten metal in the runner, thus achieving good shrinkage compensation from the runner to the ingate. At this time, the runner does not need to be coated with heat-insulating paint, and the piston casting mold will not experience piston blank porosity problems during long-term operation.

[0025] The piston casting mold in-sprue cooling method provided by this invention includes the following steps: Step S1: After the molten metal is poured, a cooling medium is introduced into the cooling channel, and the flow rate of the cooling medium is 3-6 liters / minute; Step S2: The flow time of the cooling medium is controlled to be 30-50% of the total solidification time of the piston blank. The piston casting mold in-sprue cooling method provided by this invention introduces a cooling medium into the cooling channel immediately after the molten metal is poured, which can quickly reduce the mold temperature near the ingate, thereby rapidly cooling the molten metal in the ingate and providing good shrinkage compensation for the ingate; simultaneously, the cooling medium is introduced into the ingate cooling channel for 30-50% of the total solidification time of the piston blank. The purpose is to stop the cooling medium flow into the ingate cooling channel in the middle and later stages of the piston casting solidification, allowing the temperature of the ingate to react with the temperature of the piston blank, achieving an appropriate temperature increase, thereby preventing cold shuts in the piston blank due to excessively low ingate temperature in the next casting cycle. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the structure of a piston gating system in the prior art;

[0028] Figure 2-1 A front view of a specific embodiment of the piston gating system provided by the present invention;

[0029] Figure 2-2 Left view of a specific embodiment of the piston gating system provided by the present invention;

[0030] Figure 2-3 for Figure 2-1 A cross-sectional view of PP in the piston gating system shown;

[0031] Figure 2-4 for Figure 2-2 The diagram shows the structure of the piston gating system in the Q direction.

[0032] Figure 3-1 A front view of a specific embodiment of the piston casting mold provided by the present invention;

[0033] Figure 3-2 A top view of a specific embodiment of the piston casting mold provided by the present invention;

[0034] Figure 3-3 for Figure 3-2 A partially enlarged view of the Q direction in the piston casting mold shown;

[0035] Among them: 101 straight sprue; 102 slag trough; 103 horizontal sprue; 103-1 transition section; 103-2 connecting section; 104 inner sprue; 201 mold cover; 202 sprue block; 203 outer mold cover plate; 204 outer mold; 205 guide sleeve; 206 inner mold; 207 shaft pin; 208 cooling channel; 209 inlet and outlet. Detailed Implementation

[0036] The core of this invention is to provide a piston gating system that prevents turbulence and poor feeding during molten metal casting, avoiding common defects in piston blanks and enabling the production of high-quality piston blanks. Another core aspect of this invention is to provide a piston casting mold including the aforementioned piston gating system and a method for cooling its ingate.

[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] Please refer to Figures 2 and 3. Figure 2-1 A front view of a specific embodiment of the piston gating system provided by the present invention; Figure 2-2 Left view of a specific embodiment of the piston gating system provided by the present invention; Figure 2-3 for Figure 2-1 A cross-sectional view of PP in the piston gating system shown; Figure 2-4 for Figure 2-2 The diagram shows the structure of the piston gating system in the Q direction. Figure 3-1 A front view of a specific embodiment of the piston casting mold provided by the present invention; Figure 3-2 A top view of a specific embodiment of the piston casting mold provided by the present invention; Figure 3-3 for Figure 3-2 A magnified view of the Q direction in the piston casting mold shown.

[0039] In this embodiment, the piston gating system includes:

[0040] The sprue 101 is used to allow molten metal to enter the runner 103;

[0041] A horizontal sprue 103 transitions from the sprue 101 to the ingate 104. The horizontal sprue 103 includes a transition section 103-1 and a connecting section 103-2. One end of the transition section 103-1 is connected to the sprue 101, and the other end is connected to the connecting section 103-2. The end of the connecting section 103-2 away from the transition section 103-1 is connected to the ingate 104. The transition section 103-1 extends in an arc shape, and its cross-sectional area gradually decreases from the side closer to the sprue 101 to the side closer to the connecting section 103-2. The width of the connecting section 103-2 gradually decreases from the side closer to the horizontal sprue 103 to the other side. The upper and lower sides of the connecting section 103-2 are respectively provided with an upper conical surface and a lower conical surface, and the distance between the upper and lower conical surfaces gradually increases from the side closer to the connecting section 103-2 to the other side.

[0042] The ingate 104 is used to connect the runner 103 and the cavity.

[0043] Specifically, the sprue 101 is the casting inlet. Molten metal, such as molten aluminum, enters the runner 103 through the sprue 101. It first flows through the transition section 103-1 of the runner 103. Since the transition section 103-1 has an arc structure, the flow of molten metal is buffered. Then, it enters the ingate 104 through the connecting section 103-2 of the runner 103. The runner 103 has an arc bend and a gradually changing cross-section structure, which ensures that the molten metal in the sprue 101 smoothly transitions to the ingate 104, avoiding turbulence in the casting system, thereby eliminating air entrapment and secondary oxidation slag inclusions, and improving the casting quality of the piston blank.

[0044] In some embodiments, the sprue 101 is provided with a plurality of slag-holding grooves 102, the extending direction of the slag-holding grooves 102 being perpendicular to the extending direction of the sprue 101, and the slag-holding grooves 102 being arranged along the extending direction of the sprue 101. Specifically, the sprue 101 is provided with multiple parallel slag-holding grooves 102 for catching any oxide scale and oxide inclusions that may exist in the molten metal in the sprue 101, preventing them from flowing into the casting system, thereby preventing oxide inclusions from entering the casting system.

[0045] In some embodiments, the upper conical surface slopes upward from the side closest to the transition section 103-1 to the other side, and the lower conical surface slopes downward from the side closest to the transition section 103-1 to the other side, such as... Figure 2-1 and Figure 2-4 As shown, the connecting section 103-2 gradually increases in height and gradually decreases in width from the side near the transition section 103-1 to the side near the ingate 104, realizing the transition from a cylindrical structure to a flat structure. This setting can ensure that all the molten metal from the sprue 101 flows quickly into the grate 103, avoiding the accumulation of molten metal and improving fluidity.

[0046] In some embodiments, the slag-hanging groove 102 has a width of d, a depth of (0.5-1)d, a spacing between adjacent slag-hanging grooves 102 of (2-3)d of the width, and a length equal to the width of the sprue 101, facilitating processing. Preferably, the width d of the slag-hanging groove 102 is 1-2 mm. This configuration effectively blocks oxide scale and oxide inclusions while reducing the impact on the fluidity of the molten metal.

[0047] In some embodiments, the thickness of the lower end of the skirt of the piston blank is A, the downward slope of the lower conical surface is B, where B is 20-30°, and the upward slope of the upper conical surface is C, where C is 25-35°. Figure 2-1 As shown, the slope of the upper conical surface should be just enough to connect with the inner sprue 104. The slope of the lower conical surface should not be too large, which would cause the impact speed of the molten metal to be too high and affect the quality of the blank. It should also not be too small, which would result in poor fluidity of the molten metal. Therefore, it is preferred to be 20-30° to meet the fluidity requirements while avoiding excessive impact speed.

[0048] In some embodiments, the height D of the transition section 103-1 in the horizontal runner 103 is equal to (2.5-4)A, and the value of D is generally between 20-40mm. This setting avoids the transition section 103-1 from being too high, causing unnecessary waste, and also avoids the transition section 103-1 from being too low, which would affect the flow rate of the molten metal. Therefore, it is preferred to be 2.5-4 times A.

[0049] In some embodiments, the angle between the connecting section 103-2 of the horizontal runner 103 and the center line of the cavity is F, where F = 15-25°. Specifically, this angle should not be too large to ensure that the molten metal flows smoothly into the ingate, and it should not be too small to avoid the impact of the molten metal on the molten metal in the cavity.

[0050] In some embodiments, the maximum distance between the runner 103 and the center line of the cavity is G, where G equals (0.8-1.1)E, and the value of G is generally between 5-11 mm. Specifically, the maximum distance between the runner 103 and the center line of the cavity should not be too large, because if the value of G is too large, the length of the runner 103 will be too long, resulting in excessive temperature loss when the molten metal flows through the runner 103. It should also not be too small, so as to avoid the molten metal from making a rapid turn and causing turbulence when flowing from the sprue 101 through the runner 103.

[0051] In some embodiments, the maximum thickness of the horizontal runner 103 is H, where H equals (0.7-1)D. Specifically, the thickness of the horizontal runner 103 should not be too large, because if the thickness of the horizontal runner 103 is too large, the ratio of the cross-sectional area of ​​the horizontal runner 103 to the cross-sectional area of ​​the sprue 101 will be too large, thereby excessively reducing the speed at which the molten metal flows through the horizontal runner 103, which is not conducive to the filling of the mold. It should also not be too small, so as to avoid the molten metal solidifying too quickly in the horizontal runner 103, which would not be able to complete the feeding of the ingate 104 and cause the piston to become loose.

[0052] In some embodiments, the outer arc value of the transition section 103-1 of the horizontal runner 103 is RI, where RI = 20-30 mm; the inner arc value of the transition section 103-1 of the horizontal runner 103 is RJ, where RJ = 5-10 mm. Specifically, the principle for selecting the outer and inner arc values ​​of the transition section 103-1 of the horizontal runner 103 is as follows: an appropriate combination of outer and inner arc values ​​is intended to ensure a smooth transition in the flow direction of the molten metal from the sprue 101 to the horizontal runner 103 without abrupt changes, thus avoiding turbulent flow and air entrapment. If the outer arc value RI is too large or too small, the flow velocity of the molten metal on the outer arc of the horizontal runner 103 will change too much, resulting in turbulence. Similarly, if the inner arc value RJ is too large or too small, the flow velocity of the molten metal on the inner arc of the horizontal runner 103 will change too much, resulting in turbulence.

[0053] In some embodiments, the ingate 104 is provided with an ingate, the width of which is E, which is equal to (0.7-1)A. The value of E is generally between 6-10mm. Specifically, the width of the ingate should not be too large, because if the width of the ingate is too large, the solidification speed of the molten metal in the ingate 104 will be too slow, resulting in looseness. It should also not be too small, so as to avoid the phenomenon of molten metal jetting due to excessive casting speed in the ingate 104, thereby producing oxide inclusion defects.

[0054] In some embodiments, the width of the sprue 101 is K, K = (3-4)E; specifically, the width of the sprue (101) should not be too large, because if the width of the sprue 101 is too large, the inner surface area of ​​the sprue 101 will be too large, resulting in excessive temperature loss of the molten metal flowing through the sprue 101. It should not be too small, because if the width is too small, the cross-sectional area of ​​the sprue 101 will be too small, resulting in excessive speed of the molten metal flowing through the sprue 101, causing slag inclusion and gas entrapment in the molten metal.

[0055] In some embodiments, the distance between the sprue 101 and the ingate is L, where L = (0.5-0.7) times the radius of the piston blank, and the radius of the piston blank is the structural dimension of the piston blank product, so as to ensure that the molten metal smoothly transitions to the ingate 104.

[0056] In some embodiments, the minimum depth of the sprue 101 is M, where M = (0.5-0.7)K; and the upward opening slope of the sprue 101 is N, where N = 2-3°.

[0057] The above dimensions are applicable to the processing of general aluminum piston blanks. When the piston structure is abnormal, appropriate adjustments can be made to ensure smooth filling of the piston gating system and eliminate defects such as air entrapment and slag inclusion in the piston blank. This piston gating system can achieve slag adhering to the sprue 101 and smooth flow in the gating system without air entrapment or slag inclusion.

[0058] In addition to the piston runner system described above, the present invention also provides a piston casting mold, including a mold body and the piston runner system described above disposed within the mold body.

[0059] In some embodiments, cooling channels 208 are provided on the left and right sides of the mold body near the gate of the casting system. The cooling channels 208 are used for the flow of cooling medium. Specifically, the cooling channels 208 are provided on at least one side of the gate of the casting system. In order to ensure uniform cooling, it is preferable to provide at least one cooling channel 208 on both the left and right sides of the gate of the casting system. Cooling medium, preferably cooling water, can be introduced into the cooling channels 208.

[0060] In some embodiments, the mold body includes an inner mold 206 and an outer mold 204. The outer mold 204 includes a left outer mold 204 and a right outer mold 204. A cooling channel 208 is formed on the outer mold 204. The diameter of the cooling channel 208 is 6-8mm. The distance between the cooling channel 208 and the horizontal sprue 103 on the outer mold 204 is T, where T = 4-6mm. The distance between the cooling channel 208 and the cavity of the outer mold 204 is U, where U = 4-6mm. This arrangement facilitates processing and allows the cooling channel to be as close as possible to the sprue and cavity of the outer mold 204, enabling rapid cooling of the inner gate.

[0061] In some embodiments, the cooling channel 208 includes a left cooling channel 208 and a right cooling channel 208, with the left cooling channel 208 located on the left outer mold 204 and the right cooling channel 208 located on the right outer mold 204. The left cooling channel 208 and the right cooling channel 208 are symmetrically arranged with respect to the center lines of the left outer mold 204 and the right outer mold 204.

[0062] In some embodiments, the cooling channel 208 includes an interface channel and a channel body located inside the outer mold 204. The interface channel has an inlet / outlet 209 on its outer side. The angle between the interface channel and the centerline of the outer mold 204 is S, where S = 35-55°. Specifically, each cooling channel 208 includes two interface channels and a channel body located inside the outer mold 204. One interface channel serves as an inlet channel and the other as an outlet channel. The interface channel has an inlet / outlet 209 on its outer side to allow the cooling medium to flow into the channel body. The vertical length of the channel body is V. The value of V should be as large as possible and determined according to the specific mold material characteristics. For ordinary H13 heat-resistant mold steel, it is generally sufficient to ensure that the mold wall thickness around the interface channel is 5-6 mm.

[0063] In some implementations, the actual size of the piston runner system should be 1.005-1.006 times the design size. Specifically, the piston runner system can be enlarged from the design size by a ratio of 1.005-1.006, and two ingate cooling channels 208 are provided on the left and right sides of the ingate of the mold. The distance between the cooling channel 208 and the cavity of the outer mold 204 should be as small as possible. See the above description for specific solutions.

[0064] In one specific embodiment, the piston casting mold includes an inner mold 206, a guide sleeve 205, an outer mold 204, an outer mold cover plate 203, a sprue block 202, a mold cover 201, and a shaft pin 207. The outer mold 204, the outer mold cover plate 203, the sprue block 202, and the shaft pin 207 each include left and right parts. The dimensions of the sprue system of the mold are consistent with the shape of the blank sprue system, and its dimensions are enlarged according to a ratio of 1.005-1.006. In this mold structure, two cooling channels 208 for the inner gate are set at the left and right positions of the inner gate, which are very close to the inner gate. These channels are used to quickly cool both sides of the inner gate 104, thereby generating a reasonable temperature distribution gradient for the casting system and eliminating porosity.

[0065] In addition to the piston casting mold described above, the present invention also provides a method for cooling the inlet gate of the piston casting mold applied to the piston casting mold described above, comprising the following steps:

[0066] Step S1: After the molten metal is poured, a cooling medium is introduced into the cooling channel 208 at a flow rate of 3-6 liters / minute.

[0067] Step S2: Control the flow time of the cooling medium to be 30-50% of the total solidification time of the piston blank. Specifically, after casting is completed, the cooling medium is immediately introduced. When the solidification time of the entire piston blank casting is T, the water flow time of the inner gate cooling channel 208 is 0.3-0.5T.

[0068] The piston casting mold inlet gate cooling method provided by this invention introduces a cooling medium into the cooling channel 208 immediately after the molten metal is poured. This rapidly reduces the mold temperature near the inlet gate 104, thereby quickly cooling the molten metal in the inlet gate 104 and providing good shrinkage compensation for the inlet gate 104. Simultaneously, the cooling medium is introduced into the inlet gate cooling channel 208 for 30-50% of the entire solidification time of the piston blank. The purpose is to stop the cooling medium flow into the inlet gate cooling channel 208 during the later stages of piston casting solidification, allowing the temperature of the inlet gate 104 to react with the temperature of the piston blank, achieving a slight temperature increase. This prevents the piston blank from experiencing cold shut-off due to the inlet gate 104 being too cold in the next casting cycle.

[0069] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0070] The piston gating system provided by this invention has been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the embodiments above are merely for the purpose of helping to understand the method and core ideas of this invention. It should be noted that those skilled in the art can make various improvements and modifications to this invention without departing from its principles, and these improvements and modifications also fall within the protection scope of the claims of this invention.

Claims

1. A piston gating system, characterized in that, include: The sprue (101) is used to allow molten metal to enter the runner (103). A horizontal sprue (103) transitions from the sprue (101) to the ingate (104). The horizontal sprue (103) includes a transition section (103-1) and a connecting section (103-2). One end of the transition section (103-1) is connected to the sprue (101), and the other end is connected to the connecting section (103-2). The end of the connecting section (103-2) away from the transition section (103-1) is connected to the ingate (104). The transition section (103-1) extends in an arc shape, and the transition section (103-1) has an arc shape. The cross-sectional area gradually decreases from the side closer to the sprue (101) to the side closer to the connecting section (103-2); the width of the connecting section (103-2) gradually decreases from the side closer to the runner (103) to the other side, and the upper and lower sides of the connecting section (103-2) are respectively provided with an upper conical surface and a lower conical surface, and the distance between the upper conical surface and the lower conical surface gradually increases from the side closer to the connecting section (103-2) to the other side; the angle between the connecting section (103-2) of the runner (103) and the center line of the cavity is F, where F=15-25°; The ingate (104) is used to connect the runner (103) and the cavity.

2. The piston runner system according to claim 1, characterized in that, The cast-in-place channel (101) is provided with a plurality of slag-hanging grooves (102), the extension direction of the slag-hanging grooves (102) is perpendicular to the extension direction of the cast-in-place channel (101), and each of the slag-hanging grooves (102) is arranged along the extension direction of the cast-in-place channel (101).

3. The piston runner system according to claim 2, characterized in that, The width of the slag-hanging trough (102) is d, the depth is (0.5-1)d, and the distance between adjacent slag-hanging troughs (102) is (2-3)d of the width.

4. The piston runner system according to any one of claims 1 to 3, characterized in that, The thickness of the lower end of the skirt of the piston blank is A, the downward slope of the lower conical surface is B, B is 20-30°, and the upward slope of the upper conical surface is C, C is 25-35°.

5. The piston runner system according to claim 4, characterized in that, The ingate (104) is provided with an ingate, the width of which is E; the height D of the transition section (103-1) in the runner (103) is (2.5-4)A; the maximum distance between the runner (103) and the center line of the cavity is G, which is (0.8-1.1)E; the maximum thickness of the runner (103) is H, which is (0.7-1)D; the arc value of the outer side of the transition section (103-1) of the runner (103) is RI, which is 20-30mm; the arc value of the inner side of the transition section (103-1) of the runner (103) is RJ, which is 5-10mm.

6. The piston runner system according to claim 4, characterized in that, The ingate (104) is provided with an ingate, the width of which is E, which is equal to (0.7-1)A; the width of the sprue (101) is K, which is (3-4)E; the distance between the sprue (101) and the ingate is L, which is (0.5-0.7) times the radius of the piston blank; the minimum depth of the sprue (101) is M, which is (0.5-0.7)K; the upward opening slope of the sprue (101) is N, which is 2-3°.

7. A piston casting mold, comprising a mold body and a piston runner system disposed within the mold body, characterized in that, The piston runner system is the piston runner system according to any one of claims 1 to 6; and cooling channels (208) are provided on the left and right sides of the inner gate of the piston runner system in the mold body, and the cooling channels (208) are used for the circulation of cooling medium.

8. The piston casting mold according to claim 7, characterized in that, The mold body includes an inner mold (206) and an outer mold (204). The cooling channel (208) is opened on the outer mold (204). The diameter of the cooling channel (208) is 6-8mm. The distance between the cooling channel (208) and the horizontal runner (103) on the outer mold (204) is T, where T=4-6mm. The distance between the cooling channel (208) and the cavity of the outer mold (204) is U, where U=4-6mm.

9. The piston casting mold according to claim 8, characterized in that, The cooling channel (208) includes an interface channel and a channel body located inside the outer mold (204). The interface channel is provided with an inlet and outlet (209) on its outer side. The interface channel and the center line of the outer mold (204) form an angle S, where S = 35-55°.

10. A method for cooling the gate in a piston casting mold, applied in the piston casting mold as described in any one of claims 7-9, characterized in that, Includes the following steps: Step S1: After the molten metal is poured, a cooling medium is introduced into the cooling channel (208), and the flow rate of the cooling medium is 3-6 liters / minute; Step S2: Control the flow time of the cooling medium to be 30-50% of the total solidification time of the piston blank.

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