JP5564789B2 - Casting apparatus and casting method - Google Patents

Description

  The present invention relates to a casting apparatus and a casting method for performing casting by supplying a molten metal to a cavity of a casting mold in a state where a core pin is disposed in the casting mold.

Conventionally, when casting using a cast pin, the cast pin has a double pipe structure as its cooling structure, and the cooling water is supplied into the internal pipe, and the supplied cooling water is supplied to the internal pipe and the external pipe. What discharges outside through a discharge passage having an annular groove between the two is known (see Patent Document 1 below).
Japanese Patent No. 3616616

  By the way, the above-mentioned conventional one is provided with a plurality of annular grooves spaced apart from each other in the axial direction as a cooling water passage between the inner pipe and the outer pipe, and a plurality of annular grooves extending in the axial direction. Communicate with each other. For this reason, the flow until the cooling water that has entered the annular groove flows out to the adjacent annular groove through the communication groove is not smooth, and there is a risk that the cooling water stagnates in the annular groove. There is a problem that the surface temperature of the outer periphery becomes uneven.

  Accordingly, an object of the present invention is to make the surface temperature of the core pin uniform by suppressing the stagnation of the flow of the cooling medium.

The present invention relates to a spiral groove serving as a spiral cooling medium passage in which a cooling pipe is inserted and disposed in a hollow casting pin and a cooling medium flows on the inner circumferential surface of the casting pin facing the outer circumferential surface of the cooling pipe. And connecting one end of the spiral cooling medium passage to the distal end of the internal cooling medium passage formed inside the cooling pipe, and the base end of the internal cooling medium passage and the spiral cooling medium passage. One of the other end portions is used as an inlet portion for the cooling medium, and the other is used as an outlet portion for the cooling medium , and the spiral groove is the spiral cooling medium passage that forms the spiral groove. It characterized that you have to close the cavity by one end or side as the depth of the groove located on either downstream side of the other end portion is deeply formed.

  According to the present invention, since the cooling medium smoothly flows through the cooling medium passage formed in a spiral shape, the occurrence of stagnation of the cooling medium can be suppressed, and the surface temperature of the core pin can be made uniform. At that time, since the spiral cooling medium passage is constituted by a spiral groove formed on the inner peripheral surface of the core pin, the spiral coolant passage is located closer to the cavity located on the outer peripheral side of the core pin and is supplied to the cavity. The cooling effect on the molten metal can be enhanced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a front view showing a core pin 1 showing an embodiment of the present invention and a cooling pipe 3 integrated with the core pin 1, and is made of an aluminum alloy of the automobile V-type engine shown in FIG. A cylinder bore 7 of a linerless cylinder block (hereinafter simply referred to as a cylinder block) 5 is formed by casting.

  That is, in the state where the above-described bore forming portion 9 of the core pin 1 is inserted and set in a region 11 corresponding to the inside of the cylinder bore 7 in FIG. The cylinder bore 7 is formed by supplying molten metal to a cavity formed between the mold body.

  The core pin 1 has a bottomed hollow cylindrical shape as shown in FIG. The cast pin 1 has a female screw portion 15 formed on the inner peripheral surface of the right-side opening 13 in FIG. 3A, and the outer periphery of the cooling tube 3 on the proximal end side. By screwing and fastening the male screw portion 17 formed on the surface, it is integrated with the cooling pipe 3 as shown in FIG.

  A flange portion 19 is formed on the further end side of the male screw portion 17 formed on the cooling pipe 3, and the cylindrical portion 21 on the tip side of the cooling pipe 3 is inserted into the core pin 1 as shown in FIG. In an integrated state, the O-ring 23 serving as a sealing material provided on the end surface of the flange portion 19 on the male screw portion 17 side is pressed against the end surface 26 of the core pin 1. Further, in the state of FIG. 1, the tip surface 25 of the cooling pipe 3 is in a state of being separated from the bottom surface 27 of the core pin 1 through a gap 29.

  The cooling pipe 3 described above has a cylindrical shape as a whole as shown in FIG. 3B, and has a through hole 3a penetrating along the axial direction in the center, and a thin tube 30 is inserted into the through hole 3a. ing. The inside of the thin tube 30 constitutes an internal cooling water passage 31 as an internal cooling medium passage, and both ends of the thin tube 30 slightly protrude from both ends of the cooling tube 3. The end of the internal cooling water passage 31 on the flange 19 side is an inflow port 31a as an inlet portion of cooling water that is a cooling medium, and the tip end side opposite to the flange 19 is an outflow port 31b of the cooling water. It opens to the gap 29 shown in FIG. Therefore, the cooling water supplied from the inflow port 31a passes through the internal cooling water passage 31 and flows out into the gap 29 through the outflow port 31b.

  Further, an elastic body 37 made of rubber packing or the like serving as a fixture is attached to a part of the outer periphery of the thin tube 30 in the longitudinal direction. The outer diameter of the elastic body 37 when not inserted into the through hole 3a (natural state) is slightly larger than the inner diameter of the through hole 3a. Therefore, in a state where the thin tube 30 is inserted into the through hole 3a together with the elastic body 37 to the position shown in FIG. 3 (b), the elastic body 37 is pressed against the inner wall of the through hole 3a and is compressed and deformed. It will be fixed at. In this fixed state, a gap 32 is formed between the narrow tube 30 and the inner wall of the through hole 3a.

  The elastic body 37 in the fixed state is located substantially at the center in the longitudinal direction of the cylindrical portion 21 of the cooling pipe 3. The elastic body 37 separates the gap 32 described above into two on the left and right sides in FIG. 3B, and the gap 32 on the inlet 31a side becomes the drainage passage 32a.

  The means for fixing the thin tube 30 in the through hole 3a is not limited to the elastic body 37 described above. For example, a male screw may be formed on the outer peripheral portion corresponding to the portion where the elastic body 37 of the thin tube 30 is provided, and this male screw may be screwed and fastened to a female screw formed on the inner surface of the through hole 3a. Further, the inner diameter of the through-hole 3a on the tip side (left side in FIG. 3B) from the position where the elastic body 37 and the male screw are formed is made smaller than the inner diameter on the side that becomes the drainage passage 32a, so that the capillary 30 3B is inserted into the through hole 3a from the right side in FIG. 3B, the elastic body 37 and the male screw portion abut against the end of the reduced inner diameter portion to serve as a stopper, thereby penetrating the thin tube 30. The attachment work to the hole 3a becomes easy.

  On the other hand, the cast pin 1 has a spiral spiral groove 33 formed on the inner peripheral surface thereof facing the outer peripheral surface of the cylindrical portion 21 of the cooling pipe 3, and the spiral groove 33 and the outer peripheral surface of the cylindrical portion 21. A space formed between them becomes a spiral cooling water passage 35 as a spiral cooling medium passage through which the cooling water flows.

  The left end of the spiral cooling water passage 35 in FIG. 1 communicates with a gap 29 between the tip surface 25 of the cooling pipe 3 and the bottom surface 27 of the core pin 1, and the spiral cooling water passage 35 in FIG. The other end on the right side communicates with the drainage passage 32a through the drainage passage 3b formed in the radial direction of the cooling pipe 3.

  Therefore, here, one end portion of the spiral cooling water passage 35 is connected to the distal end portion of the internal cooling water passage 31 of the cooling pipe 3 through the gap 29, and the base end portion of the internal cooling water passage 31 is connected to the cooling water. On the other hand, the other end of the spiral cooling water passage 35 is used as the cooling water outlet (drainage passages 3b and 32a).

  Next, the operation will be described. A cast pin 1 in which the cooling pipe 3 shown in FIG. 1 is integrated with a mold body (not shown) is inserted and set in a region 11 corresponding to the cylinder bore 7 of the cylinder block 5 shown in FIG. The cylinder bore 7 (cylinder block 5) is cast-molded by supplying molten metal to a cavity formed between the punch pin 1 and the mold body.

  At this time, in the present embodiment, cooling water is supplied from a cooling water supply device (not shown) to the internal cooling water passage 31 of the cooling pipe 3 from the inlet 31a as shown by an arrow W in FIG. The cooling water supplied to the internal cooling water passage 31 flows smoothly through the spiral cooling water passage 35 around the cylindrical portion 21 of the cooling pipe 3 after flowing into the gap 29 from the outlet 31b. Go.

  Thus, the core pin 1 is cooled by the cooling water flowing through the helical cooling water passage 35. At this time, in this embodiment, since the cooling water flows in a spiral shape, the cooling water suppresses the occurrence of stagnation. However, it will flow smoothly. As a result, the surface temperature of the core pin 1 is made uniform, seizure during casting and resistance to product pull-out can be reduced, and poor hot water can be suppressed, and a high-quality cast product can be obtained.

  Cooling water that has flowed through the spiral cooling water passage 35 and used for cooling is discharged from the downstream end through the drain passages 3b and 32a.

  In the present embodiment, the spiral cooling water passage 35 is formed by forming the spiral groove 33 on the inner peripheral surface of the core pin 1. For this reason, in the present embodiment, the spiral cooling water passage 35 is formed by the cavity to which the molten metal is supplied, as compared with the case where the spiral cooling water passage is formed by forming a spiral groove on the outer peripheral surface of the cooling pipe 3. The cooling effect on the molten metal in the cavity can be increased, the cooling time for the molded product can be shortened, and the casting time can be shortened.

  In addition, by forming the spiral groove 33 on the inner peripheral surface of the core pin 1, screw-like convex portions are continuously formed between the axial grooves. It is possible to contribute to securing the strength of the cylindrical cored pin 1 by fulfilling this role.

Further, the cooling water flowing through the spiral cooling water passage 35 gradually increases in temperature as it goes downstream by receiving the heat of the molten metal, so that the cooling effect on the molten metal in the cavity tends to decrease toward the downstream side. For this reason, by forming the spiral groove 33 deeper toward the downstream side of the spiral cooling water passage 35 and approaching the cavity, the cooling effect can be enhanced toward the downstream side of the spiral cooling water passage 35. it is possible to equalize the surface temperature of the.

Moreover, since the casting pin 1 is tapered toward the distal end side due to the draft, the thickness of the cylinder bore 7 corresponding to the distal end side tends to be thicker than that on the proximal end side. For this reason, by increasing the passage area of the spiral cooling water passage 35 toward the front end side of the cast pin 1, the amount of cooling water flowing to the front end side is increased, thereby increasing the cooling effect on the thick portion. can, the surface temperature of the core pin can uniformly collapse into Rukoto a.

  The cooling effect for such a thick portion is that the cooling water flowing to the tip side is reduced by narrowing the interval in the axial direction of the spiral cooling water passage 35 toward the tip side of the cast pin 1 that is tapered by the draft. Can be achieved in the same manner as described above.

  In the above-described embodiment, the cooling water is supplied from the internal cooling water passage 31 of the cooling pipe 3. However, the internal cooling water passage 31 is used as a drainage side, and the spiral cooling is performed from the drainage passage 32a side. Cooling water may be supplied to the water passage 35.

It is a front view of the core pin integrated with the cooling pipe which shows one Embodiment of this invention. It is sectional drawing of the linerless cylinder block made from the aluminum alloy of the V-type engine for motor vehicles provided with the cylinder bore shape | molded by the cast pin of FIG. (A) is sectional drawing of the core pin of FIG. 1, (b) is sectional drawing of the cooling pipe of FIG.

Explanation of symbols

1 Casting pin 3 Cooling pipe 3b, 32a Drainage passage (cooling medium outlet)
31a Inlet (cooling medium inlet)
31 Internal cooling water passage of cooling pipe (internal cooling medium passage)
33 Spiral groove 35 Spiral cooling water passage (spiral cooling medium passage)

Claims (4)

In casting apparatus which performs casting by supplying molten metal to the cavity between the core pin of the casting mold in the state in which the pin punching cast into the molding cast, cooled to the hollow of the core pin as a hollow structure A pipe is inserted and arranged, and a spiral groove serving as a spiral cooling medium passage through which a cooling medium flows is provided on the inner peripheral surface of the core pin facing the outer peripheral surface of the cooling pipe, and the spiral cooling medium passage One end portion is connected to a distal end portion of an internal cooling medium passage formed inside the cooling pipe, and either one of a base end portion of the internal cooling medium passage and the other end portion of the spiral cooling medium passage Is the inlet of the cooling medium, one of the other is the outlet of the cooling medium,
The spiral groove is formed such that the depth of the groove is deeper toward the downstream side of the one end portion or the other end portion of the spiral cooling medium passage constituting the spiral groove. A casting apparatus characterized by being close to   The casting apparatus according to claim 1, wherein a passage area of the spiral cooling medium passage is increased toward a tip end side of the casting pin that is tapered due to a draft.   3. The casting apparatus according to claim 1, wherein an interval between the spiral cooling medium passages is narrower toward a tip end side of the casting pin that is tapered due to a draft. 4. In a casting method for performing casting by supplying molten metal to a cavity between the casting pins of the casting mold in a state where the casting pins are arranged in the casting mold,
A spiral groove formed on the inner peripheral surface of the core pin opposite to the outer peripheral surface of the cooling pipe, the spiral tube being formed by inserting and arranging a cooling pipe in the hollow with the hollow pin structure, The one end of the helical cooling medium passage formed by a spiral groove having a deeper groove depth toward the downstream side of one end or the other end of the cooling medium passage, and the cooling pipe The tip of the internal cooling medium passage formed inside is connected, and the cooling medium is supplied from either the base end of the internal cooling medium passage or the other end of the spiral cooling medium passage. The supplied cooling medium is passed through a connecting portion between one end of the spiral cooling medium passage and the tip of the internal cooling medium passage, and the other end of the inner cooling medium passage and the spiral cooling medium passage. To discharge to the outside from either one of the ends Casting method according to symptoms.

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