JP2006035231A - Casting die - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the entrapment of air into molten metal by quickly and surely exhausting air in both of a cavity and a cast plan section and reducing the pressure of the both. <P>SOLUTION: A casting die 10 is provided with: an ejector 50 for performing the reduction of pressure in the cavity 30 and a first runner 36, a second runner 38, a third runner 44 or the like as the casting plan section; a first pressure reducing passage 52 for communicating the cavity 30 with the ejector 50, and a second pressure reducing passage 54 for communicating the second runner 38 with the ejector 50. The first pressure reducing passage 52 and the second pressure reducing passage 54 are arranged at the last filling-up section of the molten metal in the cavity 30 and the second runner 38, respectively. In a cooling part 56 of the first pressure reducing passage 52 and a cooling part 58 of the second pressure reducing passage 54, heat radiation fins 59 having wavy shaped outer surface are arranged. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a casting mold for casting a cylinder block, and more particularly, to a casting mold including a decompression means for decompressing a cavity and a design part.

  When casting is performed by a die casting method, the molten metal is filled into the cavity at a high speed. Although air exists in the design portion and the cavity portion of the gate, gate, runner and the like, the quality of the cast product may be deteriorated when this air is caught in the high-speed molten metal. In order to prevent such a phenomenon of quality degradation, a vacuum die casting method is performed in which the cavity and the design portion are depressurized and the volume of the air to be entrained is reduced in advance.

  As a related prior art, Patent Document 1 discloses a casting mold for casting a cylinder block for a multi-cylinder internal combustion engine. A mold is described in which surface elevation is substantially uniform.

  In Patent Document 2, assist gates are provided at both ends in the journal axis direction (cylinder arrangement direction) in a cavity for forming a V-shaped cylinder block, and the casting quality of a pair of cylinder barrels can be made uniform. A mold for mold is described.

  In Patent Document 3, a runner is formed from the lower side of the cavity to the vicinity of the center, a gate is formed along the longitudinal direction of the runner, and molten metal is stored at the upper end of the degassing runner. A casting mold provided with a chamber is described.

  Patent Document 4 describes a casting mold in which runners are formed on both lower sides of a cavity, and a degassing runner communicating with a decompression means is provided at the upper part of the cavity which is the final filling portion of the molten metal. ing.

Japanese Patent Publication No. 7-24931 JP 2002-192306 A Japanese Patent No. 3095333 Japanese Patent No. 2784087

  Among the above prior arts, the casting mold described in Patent Document 4 is provided with a degassing runner in the final filling portion of the molten metal, so that the air in the cavity and the plan portion is efficiently exhausted, It is preferable because the air entrained in the molten metal can be considerably reduced.

  However, since the distance from the gate to the final filling portion of the molten metal in the cavity is long, and the cylinder block of the engine has a complicated shape, the exhaust resistance of the pipe in the middle increases, and the air in the cavity is exhausted quickly and sufficiently. There are cases where it is not possible. In addition, when the casting mold is provided with a sliding core, outside air may leak from the gap between the mold assembly consisting of the core and the mother mold, and this leaking outside air may be There is a risk that exhaust resistance and exhaust pressure may not be sufficient due to exhaust resistance.

  Furthermore, even when the inside of the cavity is exhausted and depressurized, when the air remains in the design part on the way to the cavity, there is a possibility that the molten metal entrains the air in the design part. In particular, when the cross-sectional area of the gate leading to the cavity is small, the gate acts like a throttle, and air tends to remain in the design portion.

  The present invention has been made in consideration of such problems, and high-quality casting molding is achieved by quickly and reliably exhausting and depressurizing air in both the cavity and the design part, and reducing entrainment of air into the molten metal. An object of the present invention is to provide a casting mold from which a product can be obtained.

  A casting mold according to the present invention includes a cavity for forming a cast product, a gate provided with a piston for injecting a molten metal, and a molten metal supplied from the gate to the cavity through a plurality of gates. A runner that is a supply passage, decompression means that decompresses the cavity and the runner, a first decompression passage that communicates the cavity and the decompression means, and communicates the runway and the decompression means. And a second decompression passage.

  As described above, by providing the respective decompression passages for the cavity and the runner, the exhaust resistance is reduced, and the air in both the cavity and the design part can be exhausted and decompressed quickly and reliably.

  In this case, when the first decompression passage and the second decompression passage are respectively provided in the final filling portion of the molten metal in the cavity and the runner, efficient exhaust along the flow of the molten metal can be performed. it can.

  In addition, when at least one of the gates is disposed in the vicinity of the second pressure reducing passage, the second pressure reducing passage can exert a pressure reducing action on the cavity portion in addition to the pressure reducing action of the design portion. it can.

  According to the casting mold according to the present invention, the air in both the cavity and the plan part can be exhausted and depressurized quickly and reliably, and the entrainment of air into the molten metal is reduced to obtain a high-quality cast product. be able to.

  Hereinafter, embodiments of the casting mold according to the present invention will be described with reference to FIGS. A casting mold 10 according to the present embodiment is for casting a cylinder block (casting product) 12 which is a part of a V-type 6-cylinder engine by an aluminum die casting method. First, the cylinder block 12 will be described.

  As shown in FIG. 1, the cylinder block 12 includes a crankcase portion 14 and a pair of first cylinder row 16a and second cylinder row 16b extending in two directions from the crankcase portion 14 in a V shape. . Each of the first cylinder row 16a and the second cylinder row 16b has three cylinder bores 18, and an angle formed between the cylinder bore 18 of the first cylinder row 16a and the cylinder bore 18 of the second cylinder row 16b is, for example, 60 °. Alternatively, it is 90 ° and has a V shape.

  A cylinder piston (not shown) is slidably fitted in each cylinder bore 18. The crankcase portion 14 is provided with a plurality of (four in this embodiment) journal walls 20 along the direction of arrow A (see FIG. 3), which is the direction in which the cylinder bores 18 are arranged. A crankshaft (not shown) is rotatably supported by a bearing cap (not shown) fastened to 20. These journal walls 20 are arranged at an intermediate position between the first cylinder row 16a and the second cylinder row 16b.

  As shown in FIG. 2, the casting mold 10 includes a stationary mold 22 on the crankcase side, a movable mold 24 on the cylinder head side, and sliding molds 26 and 28 that move on the rail to form the side surface of the cylinder. And have. The movable mold 24 can advance and retreat in the direction perpendicular to the fixed mold 22, and the sliding mold 26 can slide while sliding on the surface of the fixed mold 22.

  A cavity 30 in the space formed by the fixed mold 22, movable mold 24, sliding molds 26 and 28 and formed in the central portion has the shape of the cylinder block 12, and the cavity 30 is made of molten aluminum. A cylinder block 12 is obtained by injecting and solidifying a molten metal. The cavity 30 has a complicated shape corresponding to the cylinder block 12.

  The casting mold 10 is a pouring gate 34 provided with a piston 32 for injecting molten metal, and a passage for supplying the molten metal supplied from the pouring gate 34 to the cavity 30 with respect to the journal shaft C (see FIG. 3). The first runner 36 and the second runner 38 are arranged substantially parallel and substantially symmetrically and have substantially the same shape.

  The gate 34 has an injection sleeve 39 that holds the piston 32 so as to be able to advance and retreat, and an opening 39 a into which molten metal is introduced is provided on the upper surface in the vicinity of the end of the injection sleeve 39.

  As shown in FIG. 3, the first runner 36 is connected to a portion corresponding to the first cylinder row 16a via gates 40a, 40b, 40c and 40d, and the second runner 38 is connected to the second cylinder row. It is connected to a portion corresponding to 16b via gates 42a, 42b, 42c and 42d. The first runner 36 and the second runner 38 are connected to each other by a third runner 44 on one side (in the direction of the arrow A <b> 1) viewed from the cavity 30. On the side in this direction, assist gates 45a and 45b are provided, and the third runner 44 and the cavity 30 communicate with each other. The gate 34 is connected to a substantially central portion of the second runway 38.

  The casting mold 10 includes an ejector 50 as decompression means for decompressing the cavity 30 and the design portion, a first decompression passage 52 and a first decompression passage 52 communicating the ejector 50 with the cavity 30 and the second runner 38, respectively. 2 decompression passages 54. The first decompression passage 52 and the second decompression passage 54 join at a joining conduit 55 and are connected to the ejector 50. The first decompression passage 52 includes two pipes, and the decompression in the cavity 30 can be efficiently performed. The first decompression passage 52 and the second decompression passage 54 may be connected to individual ejectors.

  The first decompression passage 52 is provided on the side (in the direction of arrow A2), which is the final filling portion of the molten metal in the cavity 30, and the second decompression passage 54 is provided in the first runway 36, the second runway 38, and the third hot water. It is provided at the end of the second runner 38 that is the final filling portion of the melt in the passage 44.

  The cooling portion 56 of the first decompression passage 52 and the cooling portion 58 of the second decompression passage 54 are provided with heat radiation fins 59 whose outer surfaces are corrugated, respectively, so that the molten metal passing therethrough is radiated and cooled. Thereby, the molten metal that passes through the cooling unit 56 and the cooling unit 58 is solidified or becomes highly viscous, and the inflow of the molten metal to the ejector 50 is prevented. Such radiating fins 59 (and on-off valves 66 and 68 to be described later) may be provided only on one side where the molten metal is supposed to flow into the ejector 50.

  In FIG. 3 (and FIGS. 4 and 5 to be described later), the shape of the space formed by these portions is illustrated to facilitate understanding of the shapes of the gate, cavity, runner and gate. The illustration of the metal mold itself is omitted.

  Next, a procedure for casting the cylinder block 12 using the casting mold 10 configured as described above will be described.

  First, as shown in FIG. 2, the sliding dies 26 and 28 are slid toward the center, and the movable die 24 is brought into contact with the sliding dies 26 and 28 to form a cavity 30.

  Next, the ejector 50 is operated to exhaust the air in the cavity 30 and the first runner 36, the second runner 38 and the third runner 44 via the first decompression passage 52 and the second decompression passage 54, Reduce pressure. The ejector 50 has a suction action of drawing air from the sub-pipe when the compressed air passes through the main pipe, and sucks air from the merging pipe 55.

  The first decompression passage 52 is provided in the final filling portion of the molten metal in the cavity 30, has a long distance from the gate 34, and the cavity 30 has a complicated shape corresponding to the cylinder block 12 and is exhausted in the middle of the pipeline. Resistance is great. Therefore, the air in the first runner 36, the second runner 38, and the third runner 44 of the design part may not be exhausted quickly and sufficiently by the first decompression passage 52 alone. The second decompression passage 54 provided at the end of the second runner 38 is smoothly exhausted and decompressed. That is, there are no obstacles that cause exhaust resistance between the first runway 36, the second runway 38, the third runway 44, and the second decompression passage 54. Exhausted.

  Further, as described above, the cavity 30 is formed by the fixed mold 22, the movable mold 24, and the sliding molds 26 and 28. However, the outside air that leaks from a slight gap between these molds also has the first decompression passage 52 and the first mold. 2 The air is reliably exhausted from the decompression passage 54 toward the ejector 50.

  As described above, since the exhaust process is performed quickly, the cycle time of the step of casting the cylinder block 12 is shortened, and the working efficiency is improved.

  Next, while continuing the exhaust process by the ejector 50, the molten metal is poured from the opening 39 a into the gate 34, and then the molten metal is injected into the cavity 30 by the piston 32 at a high speed. The molten metal pushed out by the piston 32 is injected into the cavity 30 from the first runner 36 through the gates 40a to 40d, and from the second runner 38 through the gates 42a to 42d. The three runners 44 are injected through assist gates 45a and 45b.

  At this time, since the inside of the cavity 30 is sufficiently decompressed mainly by the first decompression passage 52, the molten metal is smoothly injected. Moreover, since the design parts such as the first runway 36, the second runway 38, and the third runway 44 are mainly sufficiently decompressed by the second decompression passage 54, the molten metal has gates 40a to 40d and gates 42a to 42a. 42d and the assist gates 45a and 45b are supplied smoothly, and air entrapment and oxidation do not occur in the design part.

  The second decompression passage 54 mainly exerts the decompression action of the plan portion. However, since the gate 42d is disposed in the vicinity of the second decompression passage, the second decompression passage 54 also exerts a decompression action on the cavity 30. You can help.

  Furthermore, a small amount of air remaining in the cavity 30 is pushed out by the molten metal, but the first decompression passage 52 is provided in the final filling portion of the molten metal in the cavity 30, so that the flow of the molten metal causes It is pushed out and discharged smoothly. Similarly, since the second decompression passage 54 is provided at the end of the second runner 38 which is the final filling portion in the design part, a small amount of air remaining in the design part is directed to the second runway 38. It will be pushed out smoothly. In this way, the air in the cavity 30 and the design part is pushed out by the molten metal and does not remain, and a cast hole is hardly generated in the cylinder block 12.

  Next, by continuously injecting the molten metal with the piston 32, the molten metal fills the cavity 30, and a part thereof flows into the first decompression passage 52. Similarly, most of the molten metal filled in the second runner 38 is injected into the cavity 30 through the gates 40 a to 40 d, but a part flows into the second decompression passage 54. As described above, the molten metal that has flowed into the first decompression passage 52 and the second decompression passage 54 is solidified or increased in viscosity by being cooled by the cooling unit 56 and the cooling unit 58, and is unnecessarily transferred to the merge pipe 55. There is no inflow, and the inflow of the molten metal to the ejector 50 is prevented.

  Next, the piston 32 is stopped, and after the molten metal is sufficiently cooled and solidified, the movable mold 24 and the sliding molds 26 and 28 are separated from the cavity 30. Further, the insert pin (not shown) is pulled out and, if a sand core is provided, the sand core is crushed and removed. Thereby, the cylinder block 12 and the unnecessary part 80 as shown in FIG. 1 are formed. The unnecessary portion 80 is formed in the first runner 36, the second runner 38, the gates 40a to 40d, the gates 42a to 42d, the third runner 44, a part of the first decompression passage 52, and a part of the second decompression passage 54. The corresponding portion is formed integrally with the cylinder block 12, and the cylinder block 12 is obtained by removing the unnecessary portion 80 by a predetermined procedure.

  Further, as shown in FIG. 4, in order to prevent the molten metal from flowing into the ejector 50, contact sensors 60 and 62 are provided on the outer walls of the inlets of the cooling portions 56 and 58 as melt passage detecting means, and the contact sensors are provided. On-off valves 66 and 68 that close under the action of the control unit 64 based on the detection signals 60 and 62 may be provided at the outlets of the cooling units 56 and 58, respectively. That is, when the temperatures detected by the contact sensors 60 and 62 are equal to or higher than a predetermined threshold value, it is determined that the molten metal approaches or passes through the cooling units 56 and 58, and the on-off valve 66 that is in the open state is opened. And 68 (or any one of them) are individually closed under the action of the control unit 64, and the inflow of the molten metal to the ejector 50 is reliably prevented. The on-off valves 66 and 68 (or one of them) may be closed in synchronism with the start of the operation of the piston 32 after the cavity 30 and the design part are decompressed.

  As the molten metal passage detection means, in addition to the contact sensors 60 and 62, a pressure sensor or a temperature sensor can be used.

  Further, as shown in FIG. 5, the gate 34 is disposed at the approximate center of the third runner 44, and the third decompression passage 70 and the cooling unit 72 communicating with the ejector 50 are provided at the end of the first runner 36. You may do it. In this case, the third decompression passage 70 has the same effect as the second decompression passage 54, and the inside of the first runner 36 can be decompressed quickly and reliably, and as a result, the design portion can be decompressed more sufficiently. it can.

  As described above, according to the casting mold 10 according to the present embodiment, the first decompression passage 52 and the second decompression passage 54 supplement each other with the exhaust action, and both the cavity 30 and the plan portion. Air can be exhausted and decompressed quickly and reliably. As a result, the cycle time of the casting process is shortened, the working efficiency is improved, and the high-quality cylinder block 12 with less air trapped in the molten metal can be obtained.

  In addition, by driving the piston 32 sufficiently fast, the influence of gravity can be relatively reduced with respect to the driving force of the piston acting on the molten metal, and the casting mold 10 has a vertical axis whose journal axis direction is vertical. The present invention can be applied to either a placement method or a horizontal placement method in which the journal axis direction is horizontal.

  By using the casting mold 10, molten metal is injected from the gates 40 a to 40 d into the portion corresponding to the first cylinder row 16 a in the cavity 30, while the gates 42 a to 42 d are applied to portions corresponding to the second cylinder row. Molten metal is poured from By providing a large number of gates in this way, the so-called hot water performance is improved.

  The cavity 30 is surrounded on three sides by the first runner 36, the second runner 38, and the third runner 44, and the molten metal is injected from the gates 40a to 40d, the gates 42a to 42d, and the assist gates 45a and 45b. be able to. By providing many gates in this way, the molten metal can be injected in a short time, and the pipe resistance to the molten metal is reduced, thereby enabling smooth injection.

  When the casting mold product of the casting mold 10 is applied to the cylinder block 12 or the like of a V-shaped engine having a complicated shape, the design portion can be decompressed particularly efficiently. Of course, it may be a shape of a cast product having a simpler shape.

  The casting mold according to the present invention is not limited to the above-described embodiment, and it is needless to say that various configurations can be adopted without departing from the gist of the present invention.

It is a side view of the cylinder block cast-molded by the casting die. It is side surface sectional drawing which shows the metal mold | die for casting which concerns on this Embodiment. It is a top view of the space part which the cavity of a casting die concerning this embodiment, a runner, and a gate form. It is a top view of the space part which the metal mold | die for casting in which the contact sensor and the on-off valve were provided in the pressure_reduction | reduced_pressure path forms. It is a top view of the space part which the metal mold | die for casting in which the 3rd decompression path was provided in the edge part of a 2nd runner.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Mold for casting 12 ... Cylinder block 14 ... Crankcase part 16a, 16b ... Cylinder row | line | column 20 ... Journal wall 22 ... Fixed type | mold 24 ... Movable type | mold 26, 28 ... Sliding type | mold 30 ... Cavity 32 ... Piston 34 ... Spout 36 ... 1st runway 38 ... 2nd runway 40a-40d, 42a-42d ... Gate 44 ... 3rd runway 45a, 45b ... Assist gate 50 ... Ejector 52 ... 1st decompression passage 54 ... 2nd decompression passage 56, 58 72 ... Cooling unit 60, 62 ... Contact sensor 66, 68 ... Open / close valve 70 ... Third decompression passage

Claims (3)

A cavity for forming a cast product,
A gate with a piston for injecting molten metal;
A runner that is a passage for supplying molten metal supplied from the gate to the cavity through a plurality of gates;
Decompression means for decompressing the cavity and the runner;
A first decompression passage communicating the cavity and the decompression means;
A second decompression passage communicating the runner and the decompression means;
A casting mold characterized by comprising: The casting mold according to claim 1, wherein
The casting mold, wherein the first decompression passage and the second decompression passage are provided in a final filling portion of the molten metal in the cavity and the runner, respectively. The casting mold according to claim 1, wherein
At least one of the gates is disposed in the vicinity of the second decompression passage.

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