JP2012076107A - Plunger tip for die-casting, and die-casting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plunger tip which can reduce the amount of solidified pieces mixed into a molten material within a cavity of a molding die device, and to provide a die-casting method using the plunger tip.SOLUTION: The plunger tip 1 for die-casting has a cylinder part 2 and a protruding part 3. The protruding part 3 is integrally provided at one end in an axial direction of the cylinder part 2. An outer diameter of the protruding part 3 becomes gradually small from the cylinder part 2 to a forefront thereof. A concave part 5 is formed at the forefront of the protruding part 3. When the plunger tip 1 moves forward inside a cylinder sleeve 11, the solidified pieces 52 peeled off from a solidifying layer 51 of the molten material are captured in space between an outer periphery 31 of the protruding part 3 of the plunger tip 1 and an inner periphery of the cylinder sleeve 11. The solidified pieces 52 leaking out from the space between the outer periphery 31 of the protruding part 3 and the inner periphery of the cylinder sleeve 11 are captured inside the concave part 5 of the protruding part 3.

Description

  The present invention relates to a die casting plunger tip and a die casting method using the same.

  Die casting equipment is used to produce castings. The die casting apparatus is composed of a mold apparatus and an injection apparatus. A cavity having a shape corresponding to the shape of the cast product is formed inside the mold apparatus. The cylinder sleeve of the injection apparatus is attached to the mold apparatus so as to communicate with the cavity. A plunger tip attached to the tip of the cylinder rod is inserted into the cylinder sleeve. Molten metal (a molten material such as a molten metal) is supplied in front of the plunger tip in the cylinder sleeve.

  As the plunger tip moves forward by the cylinder rod, the molten metal in the cylinder sleeve is pushed into the cavity of the mold apparatus. Thereby, the molten metal is filled in the cavity.

  The cylinder sleeve is provided so as to extend in the horizontal direction. For this reason, the molten metal portion that contacts the lower portion of the inner peripheral surface of the cylinder sleeve tends to solidify. Thereby, a solidified layer is formed in the lower part in the cylinder sleeve. When the plunger tip advances in this state, the solidified layer is scraped off at the tip end surface of the plunger tip, so that a part of the solidified layer is peeled off as a solidified piece. When the solidified pieces are mixed into the molten metal in the cavity of the mold apparatus, the quality of the cast product is deteriorated.

  Patent Document 1 describes a plunger tip for preventing a solidified piece from being mixed into a molten metal. The tip surface of the plunger tip constitutes a molten metal extrusion surface, and a notch is formed at least at the lower part of the molten metal extrusion surface. The notch is composed of a horizontal wall and a vertical wall. The exfoliated solidified piece is filled in the notch and is prevented from rising by the horizontal wall.

JP-A-9-295119

  However, when the temperature of the molten metal in the cylinder sleeve decreases or when the amount of the molten metal in the cylinder sleeve decreases, the thickness of the solidified layer in the cylinder sleeve increases. Also, when a delay occurs between the supply of the molten metal into the cylinder sleeve and the extrusion of the molten metal by the plunger tip, the thickness of the solidified layer in the cylinder sleeve increases. In such a case, the amount of solidified pieces that peel from the solidified layer increases. Therefore, even if the plunger tip of Patent Document 1 is used, the solidified piece overflows from the notch into the molten metal. Thereby, the quantity of the solidified piece mixed in the molten metal in the cavity of the mold apparatus increases. As a result, the quality of the cast product is deteriorated.

  An object of the present invention is to provide a plunger tip capable of reducing the amount of solidified pieces mixed into a molten material in a cavity of a mold apparatus and a die casting method using the same.

  (1) A plunger chip for die casting according to the present invention includes a cylindrical portion and a protruding portion integrally provided at one end in the axial direction of the cylindrical portion, and the protruding portion has an outer diameter that gradually decreases from the cylindrical portion to the tip. And a recess is formed at the tip.

  When a cast product is manufactured by the die casting method using the die casting plunger tip, the cylinder sleeve is attached to the mold apparatus and the plunger tip is inserted into the cylinder sleeve. Thereby, the space in the cylinder sleeve communicates with the cavity of the mold apparatus. Next, a molten material is injected into the space between the plunger tip and the mold apparatus in the cylinder sleeve.

  Of the molten material injected into the cylinder sleeve, the portion of the molten material that contacts the lower part of the inner peripheral surface of the cylinder sleeve tends to solidify. As the molten material solidifies, a solidified layer is formed in the lower portion of the cylinder sleeve.

  Thereafter, the plunger tip advances in the cylinder sleeve toward the mold apparatus, thereby pushing the molten material in the cylinder sleeve into the cavity of the mold apparatus. As a result, the molten material is filled in the cavity of the mold apparatus.

  In this case, when the plunger tip moves forward, a part of the solidified layer in the cylinder sleeve is peeled off as a solidified piece. The peeled solidified piece is captured in the space between the outer peripheral surface of the protrusion and the inner peripheral surface of the cylinder sleeve as the plunger tip advances. Since the protruding portion has an outer diameter that gradually decreases from the cylindrical portion to the tip, the space between the outer peripheral surface of the protruding portion and the inner peripheral surface of the cylinder sleeve is gradually narrowed toward the rear. Thereby, the solidified pieces are aggregated in the space between the outer peripheral surface of the protrusion and the inner peripheral surface of the cylinder sleeve.

  When the amount of the solidified pieces is large, the solidified pieces overflowing from the space between the outer peripheral surface of the protruding portion and the inner peripheral surface of the cylinder sleeve are captured in the concave portion of the protruding portion. Thereby, the amount of solidified pieces mixed in the molten material in the cavity of the mold apparatus is reduced. As a result, deterioration of the quality of the cast product is prevented.

  (2) The depth of the concave portion in the axial direction is preferably 5% or more and 200% or less of the radius of the cylindrical portion.

  When the depth of the concave portion is 5% or more of the radius of the cylindrical portion, a space having a sufficient volume can be secured inside the concave portion. Moreover, when the depth of the concave portion is 200% or less of the radius of the cylindrical portion, sufficient rigidity of the protruding portion can be ensured and stress concentration on the bottom portion of the concave portion can be reduced. Therefore, a sufficient amount of the solidified piece can be captured in the recess without reducing the strength of the plunger tip.

  (3) The concave portion has an inner peripheral surface and a bottom portion that are rotationally symmetric with respect to the axis of the cylindrical portion, and the inner diameter of the inner peripheral surface decreases linearly from the tip to the bottom, and the inner peripheral surface in the axial section of the protrusion Is preferably 5 degrees or more and 45 degrees or less.

  When the angle of the inner peripheral surface of the concave portion with respect to the axial direction is 5 degrees or more, sufficient rigidity of the protruding portion can be ensured. Further, when the liquid level of the molten material rises due to the extrusion of the molten material, the gas is prevented from being trapped in the recess. Furthermore, when taking out the cast product from the mold apparatus, the material can be easily separated from the concave portion of the plunger tip. In addition, when the angle of the inner peripheral surface of the recess with respect to the axial direction is 45 degrees or less, a space having a sufficient volume can be secured inside the recess.

  (4) It is preferable that the difference between the radius of the protruding portion and the radius of the cylindrical portion at the boundary between the cylindrical portion and the protruding portion is 0% or more and 50% or less of the radius of the cylindrical portion.

  Since the difference between the radius of the protrusion and the radius of the cylindrical portion is 50% or less of the radius of the cylinder, the solidified pieces captured in the space between the outer peripheral surface of the protrusion and the inner peripheral surface of the cylinder sleeve are removed. Aggregation tends to occur between the outer peripheral surface of the protrusion and the inner peripheral surface of the cylinder sleeve. Therefore, the solidified piece is prevented from flowing out in front of the protruding portion.

  (5) In the axial direction, the length from the boundary between the cylindrical portion and the protruding portion to the tip of the protruding portion is preferably 20% or more and 200% or less of the radius of the cylindrical portion.

  Since the length from the boundary between the cylindrical portion and the protruding portion to the tip of the protruding portion is 20% or more of the radius of the cylindrical portion, a sufficient volume is provided between the outer peripheral surface of the protruding portion and the inner peripheral surface of the cylinder sleeve. It is possible to secure a space having Therefore, the amount of solidified pieces overflowing from between the outer peripheral surface of the protrusion and the inner peripheral surface of the cylinder sleeve can be reduced. Moreover, when the length from the boundary between the cylindrical portion and the protruding portion to the tip of the protruding portion is 200% or less of the radius of the cylindrical portion, sufficient rigidity of the protruding portion can be ensured.

  (6) The projecting portion has a frustoconical outer peripheral surface, and an angle formed by the outer peripheral surface of the projecting portion with respect to the axial direction in an axial section of the projecting portion is 5 degrees or more and 45 degrees or less. preferable.

  When the angle of the outer peripheral surface of the protruding portion with respect to the axial direction is 5 degrees or more, a space having a sufficient volume can be ensured between the outer peripheral surface of the protruding portion and the inner peripheral surface of the cylinder sleeve. Therefore, the amount of solidified pieces overflowing from between the outer peripheral surface of the protrusion and the inner peripheral surface of the cylinder sleeve can be reduced. Moreover, when the angle of the outer peripheral surface of the protrusion with respect to the axial direction is 45 degrees or less, the solidified piece can be reliably captured between the outer peripheral surface of the protrusion and the inner peripheral surface of the cylinder sleeve.

  (7) It is preferable that the protruding portion has an annular end surface at the tip, and the width of the end surface in the radial direction is not less than 1% and not more than 80% of the radius of the cylindrical portion.

  When the width of the end face of the projecting portion is 1% or more of the radius of the cylindrical portion, the projecting portion can have a strength sufficient to withstand the pressure when extruding the molten material. Further, when the width of the end face of the protruding portion is 80% or less of the radius of the cylindrical portion, a space having a sufficient volume can be ensured between the outer peripheral surface of the protruding portion and the inner peripheral surface of the cylinder sleeve. At the same time, a space having a sufficient volume can be secured inside the recess.

  (8) A die casting method according to the present invention includes a step of attaching a cylinder sleeve to the mold apparatus so as to communicate with a cavity of the mold apparatus, and inserting the above-described die casting plunger tip according to the present invention into the cylinder sleeve; Injecting the molten material into the space between the plunger tip in the cylinder sleeve and the mold device, and moving the plunger tip in the cylinder sleeve toward the mold device to move the molten material in the cylinder sleeve to the mold. Pushing into the cavity of the mold apparatus.

  In this die casting method, the above-described plunger tip for die casting according to the present invention is used. When the solidified layer of the molten material is formed in the lower part in the cylinder sleeve, a part of the solidified layer in the cylinder sleeve is peeled off as a solidified piece by the advancement of the plunger tip.

  The peeled solidified piece is captured in the space between the outer peripheral surface of the protrusion and the inner peripheral surface of the cylinder sleeve as the plunger tip advances. Since the protruding portion has an outer diameter that gradually decreases from the cylindrical portion to the tip, the space between the outer peripheral surface of the protruding portion and the inner peripheral surface of the cylinder sleeve is gradually narrowed toward the rear. Thereby, the solidified pieces are aggregated in the space between the outer peripheral surface of the protrusion and the inner peripheral surface of the cylinder sleeve.

  When the amount of the solidified pieces is large, the solidified pieces overflowing from the space between the outer peripheral surface of the protruding portion and the inner peripheral surface of the cylinder sleeve are captured in the concave portion of the protruding portion. Thereby, the amount of solidified pieces mixed into the molten material in the cavity of the mold apparatus is reduced. As a result, deterioration of the quality of the cast product is prevented.

  According to the present invention, the amount of solidified pieces mixed in the molten material in the cavity of the mold apparatus is reduced. As a result, deterioration of the quality of the cast product is prevented.

It is a schematic diagram which shows the structure of the die-cast apparatus provided with the plunger chip | tip which concerns on one embodiment of this invention. It is a perspective view of the plunger tip concerning one embodiment of the present invention. It is sectional drawing along the axial direction of the plunger tip of FIG. It is the figure which looked at the plunger tip of FIG. 2 from the front. It is the figure which looked at the plunger tip of FIG. 2 from back. It is sectional drawing which shows the attachment structure of the plunger chip | tip in a cylinder sleeve. It is a figure for demonstrating the dimension of each part of a plunger tip. It is sectional drawing along the axial direction of the plunger tip which concerns on other embodiment of this invention. It is sectional drawing along the axial direction of the plunger tip which concerns on other embodiment of this invention. It is sectional drawing along the axial direction of the plunger tip which concerns on other embodiment of this invention.

  Hereinafter, a plunger tip and a die casting method using the same according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic view showing a configuration of a die casting apparatus provided with a plunger tip according to an embodiment of the present invention. A die casting apparatus 100 shown in FIG. 1 includes an injection apparatus 10 and a mold apparatus 60.

  The mold apparatus 60 includes a movable member 61, mold members 62 and 63, and a fixed member 64. The mold member 62 is attached to the movable member 61. The mold member 63 is attached to the fixing member 64.

  When the movable member 61 moves in the horizontal direction, the state is switched between a state in which the mold member 62 is joined to the mold member 63 and a state in which the mold member 62 is separated from the mold member 63. A cavity 65 is formed in a state where the mold members 62 and 63 are joined. The cavity 65 has a shape corresponding to the shape of the cast product. A molten metal supply port 66 is formed in the fixing member 64 and the mold member 63. A runner 67 is formed on the mold member 63.

  The injection device 10 includes a plunger tip 1, a cylinder sleeve 11, a cylinder rod 13, and a drive device 14. The cylinder sleeve 11 has a cylindrical shape. The tip of the cylinder sleeve 11 is fitted into the molten metal supply port 66 of the mold apparatus 60. The cylinder sleeve 11 extends in the horizontal direction. An inlet 12 is formed in the upper part of the cylinder sleeve 11.

  The plunger tip 1 is inserted into the cylinder sleeve 11. Hereinafter, the direction in which the plunger tip 1 is directed toward the mold device 60 is referred to as the front, and the direction in which the plunger tip 1 is separated from the mold device 60 is referred to as the rear.

  A cylinder rod 13 is attached to the rear end of the plunger tip 1. The cylinder rod 13 extends in the horizontal direction within the cylinder sleeve 11. The drive device 14 moves the cylinder rod 13 in the front-rear direction.

  The space inside the cylinder sleeve 11 communicates with the cavity 65 through the molten metal supply port 66 and the runner 67 of the mold apparatus 60. Molten material is injected from the inlet 12 of the cylinder sleeve 11. The molten material is a molten metal, a molten alloy, a molten resin, or the like. For example, molten aluminum is used as the molten material. Hereinafter, the molten material is referred to as a molten metal 70.

  When the cylinder rod 13 is driven forward by the driving device 14, the plunger tip 1 moves forward in the cylinder sleeve 11. Thereby, the molten metal 70 in the cylinder sleeve 11 is extruded into the cavity 65 through the molten metal supply port 66 and the runner 67 of the mold device 60. Thereby, the molten metal 70 is filled in the cavity 65.

  FIG. 2 is a perspective view of the plunger tip 1 according to the embodiment of the present invention. FIG. 3 is a sectional view taken along the axial direction of the plunger tip 1 of FIG. FIG. 4 is a view of the plunger tip 1 of FIG. 2 as viewed from the front. FIG. 5 is a rear view of the plunger tip 1 of FIG.

  As shown in FIG. 2, the plunger tip 1 includes a cylindrical portion 2, a protruding portion 3, and an attachment portion 4. Hereinafter, the central axis of the cylindrical portion 2 is referred to as an axis Ax of the cylindrical portion 2, and a direction parallel to the axis Ax of the cylindrical portion 2 is referred to as an axial direction. The plunger tip 1 is made of, for example, a steel material such as SKD61, a nickel alloy, or the like. The material of the plunger tip 1 is not limited to these materials.

  The protruding portion 3 is integrally provided on the front end surface of the cylindrical portion 2 in the axial direction. The attachment portion 4 is integrally provided on the rear end surface in the axial direction of the cylindrical portion 2.

  As shown in FIG. 3, the protruding portion 3 has an outer diameter that gradually decreases from the cylindrical portion 2 to the tip. In the present embodiment, the protrusion 3 has a frustoconical outer peripheral surface 31. A concave portion 5 is formed on the tip surface of the protruding portion 3. In the present embodiment, the concave portion 5 has an inner peripheral surface 51 and a bottom portion 52 that are rotationally symmetric with respect to the axis Ax of the cylindrical portion 2. The inner diameter of the inner peripheral surface 51 decreases linearly from the tip to the bottom 52. Thereby, the recessed part 5 has an inverted truncated cone shape. The maximum radius of the recess 5 is smaller than the radius of the tip of the outer peripheral surface 3 of the protrusion 3. Thereby, an annular end surface 32 is formed at the tip of the protrusion 3 as shown in FIGS. 3 and 4.

  Further, the radius of the protruding portion 3 is smaller than the radius of the cylindrical portion 2 at the boundary between the protruding portion 3 and the cylindrical portion 2. Thereby, as shown in FIGS. 3 and 4, an annular shoulder portion 21 is formed at the boundary between the projecting portion 3 and the cylindrical portion 2.

  The protruding portion 3 functions as a pressing portion, and in the present embodiment, the outer peripheral surface 31 and the end surface 32 of the protruding portion 3, the inner peripheral surface 51 and the bottom portion 52 of the concave portion 5, and the shoulder portion 21 constitute a pressing surface.

  As shown in FIG. 3, a cylindrical inner space 22 that is rotationally symmetric with respect to the axis Ax is formed in the cylindrical portion 2. Moreover, the attachment part 4 has a cross-sectional square shape, as shown in FIG. As shown in FIGS. 3 and 4, the attachment portion 4 is formed with a cylindrical opening 23 that is rotationally symmetric with respect to the axis Ax. A mounting hole 24 that is rotationally symmetric with respect to the axis Ax is formed between the internal space 22 of the cylindrical portion 2 and the opening 23. The inner diameter of the internal space 22 is larger than the inner diameter of the mounting hole 24. The inner diameter of the opening 23 is larger than the inner diameter of the mounting hole 24. A female screw 24 a is formed on the inner peripheral surface of the mounting hole 24.

  FIG. 6 is a cross-sectional view showing the mounting structure of the plunger tip 1 in the cylinder sleeve 11.

  As shown in FIG. 6, the cylinder rod 13 is attached to the plunger tip 1 using a connecting member 15. The connecting member 15 has a through-hole penetrating from the rear end surface to the front end surface. A male screw corresponding to the female screw 24 a (FIG. 3) of the mounting hole 24 of the plunger tip 1 is formed on the outer peripheral surface of the distal end portion of the connecting member 15. The connecting member 15 is attached to the attachment hole 24 (FIG. 3) of the plunger tip 1 through the opening 23 (FIG. 3). The cylinder rod 13 is formed in a tubular shape. The front end of the cylinder rod 13 is attached to the rear end portion of the connecting member 15. The cylinder rod 13 and the connecting member 15 may be integrally formed.

  The cooling water pipe 16 is inserted so as to penetrate the internal space of the cylinder rod 13 and the connecting member 15. The tip of the cooling water pipe 16 protrudes into the internal space 22 of the plunger tip 1. Cooling water is supplied to the internal space 22 of the plunger tip 1 through the cooling water pipe 16. The cooling water in the internal space 22 is discharged outside through a space between the inner peripheral surface of the cylinder rod 13 and the outer peripheral surface of the cooling water pipe 16.

  In this state, the plunger tip 1 and the cylinder rod 13 are inserted into the cylinder sleeve 11. The inner diameter of the cylinder sleeve 11 and the outer diameter of the cylindrical portion 2 of the plunger tip 1 are substantially equal. As the cylinder rod 13 moves back and forth, the plunger tip 1 slides back and forth within the cylinder sleeve 11.

  Here, a die casting method using the plunger tip 1 according to the present embodiment will be described with reference to FIGS. 1 and 6.

  First, as shown in FIG. 1, the cylinder sleeve 11 is attached to the molten metal supply port 66 of the mold apparatus 60. Further, the plunger tip 1 to which the cylinder rod 13 is attached is inserted into the cylinder sleeve 11. Thereby, the space in front of the plunger tip 1 in the cylinder sleeve 11 communicates with the cavity 65 of the mold apparatus 60 through the runner 67.

  Next, the molten metal 70 is injected into the space in front of the plunger tip 1 in the cylinder sleeve 11 from the injection port 12 of the cylinder sleeve 11. Of the molten metal 70 injected into the cylinder sleeve 11, the portion of the molten metal 70 that contacts the lower portion of the inner peripheral surface of the cylinder sleeve 11 tends to solidify. As the molten metal 70 solidifies, a solidified layer 71 is formed in the lower portion of the cylinder sleeve 11 as shown in FIG.

  Thereafter, the plunger rod 1 is moved toward the mold device 60 in the cylinder sleeve 11 by advancing the cylinder rod 13 by the drive device 14 of FIG. As a result, the molten metal 70 in the cylinder sleeve 11 is pushed into the cavity 65 in the mold apparatus 60. As a result, the molten metal 70 is filled into the cavity 65 and the runner 67 of the mold apparatus 60.

  At this time, as shown in FIG. 6, when the plunger tip 1 moves forward, a part of the solidified layer 71 in the cylinder sleeve 11 is peeled off as a solidified piece 72. The peeled solid piece 72 is captured in the space between the outer peripheral surface 31 of the protrusion 3 and the inner peripheral surface of the cylinder sleeve 11 as the plunger tip 1 moves forward. Since the protruding portion 3 has an outer diameter that gradually decreases from the cylindrical portion 2 to the tip, the space between the outer peripheral surface 31 of the protruding portion 3 and the inner peripheral surface of the cylinder sleeve 11 becomes gradually narrower toward the rear. As a result, the solidified pieces 72 are aggregated in the space between the outer peripheral surface 31 of the protrusion 3 and the inner peripheral surface of the cylinder sleeve 11.

  Further, when the amount of the solidified layer 71 is large, the solidified piece 72 overflowing from the space between the outer peripheral surface 31 of the protruding portion 3 and the inner peripheral surface of the cylinder sleeve 11 is captured in the concave portion 5 of the protruding portion 3. Is done. Thereby, the amount of solidified pieces 72 mixed in the molten metal 70 in the cavity 65 of the mold apparatus 60 of FIG. 1 is reduced. As a result, deterioration of the quality of the cast product is prevented.

  FIG. 7 is a view for explaining the dimensions of each part of the plunger tip 1.

  In FIG. 7, let R be the radius of the cylindrical portion 2 of the plunger tip 1. The amount of the solidified piece 72 peeled from the solidified layer 71 of the molten metal 70 in the cylinder sleeve 11 depends on the radius of the cylinder sleeve 11. Since the radius R of the cylindrical portion 2 of the plunger tip 1 is substantially equal to the radius of the cylinder sleeve 11, the amount of the solidified piece 72 depends on the radius R of the cylindrical portion 2. Therefore, the preferable dimension of each part of the plunger tip 1 is expressed on the basis of the radius R of the cylindrical part 2.

  Let D be the depth of the recess 5 in the axial direction of the cylindrical portion 2 (the direction of the axis Ax). The depth D of the recess 5 is preferably 5% or more and 200% or less of the radius R of the cylindrical part 2. When the depth D of the concave portion 5 is 5% or more of the radius R of the cylindrical portion 2, a space having a sufficient volume inside the concave portion 5 can be secured. Further, when the depth D of the concave portion 5 is 200% or less of the radius R of the cylindrical portion 2, the ratio of the axial height of the protruding portion 3 to the width b of the annular bottom portion of the protruding portion 3 is increased. Only. Thereby, sufficient rigidity of the protrusion 3 can be ensured and stress concentration on the bottom 52 of the recess 5 can be reduced. Accordingly, a sufficient amount of the solidified piece can be captured in the recess 5 without reducing the strength of the plunger tip 1.

  An angle formed by the inner peripheral surface 51 of the concave portion 5 with respect to the axial direction in the cross section in the axial direction of the protruding portion 3 is defined as α. The angle α of the inner peripheral surface 51 is preferably 5 degrees or greater and 45 degrees or less. When the angle α of the inner peripheral surface 51 is 5 degrees or more, sufficient rigidity of the protruding portion 3 can be ensured. Further, when the liquid level of the molten metal 70 is raised by the extrusion of the molten metal 70, the gas is prevented from being trapped in the recess 5. Furthermore, when the cast product is taken out from the mold apparatus 60, the solidified material can be easily separated from the concave portion 5 of the plunger tip 1. Moreover, when the angle α of the inner peripheral surface 51 is 45 degrees or less, a space having a sufficient volume can be secured inside the recess 5.

  Let r be the radius of the protrusion 2 at the boundary between the cylindrical portion 2 and the protrusion 3. The difference between the radius R of the cylindrical portion 3 and the radius r of the protruding portion 3 corresponds to the width of the shoulder portion 21. Let the width of the shoulder 21 be ΔR. The width ΔR of the shoulder portion 21 is preferably 0% or more and 50% or less of the radius R of the cylindrical portion 2. When the width ΔR of the shoulder portion 21 is 50% or less of the radius R of the cylindrical portion 2, the solidified piece 72 captured in the space between the outer peripheral surface 31 of the protruding portion 3 and the inner peripheral surface of the cylinder sleeve 11 is obtained. Aggregation tends to occur between the outer peripheral surface 31 of the protrusion 3 and the inner peripheral surface of the cylinder sleeve 11. Therefore, the solidified piece 72 is prevented from flowing out in front of the protrusion 3.

  Let H be the length from the boundary (shoulder portion 21) between the cylindrical portion 2 and the protruding portion 3 to the tip of the protruding portion 3 in the axial direction. The length H of the protruding portion 3 is preferably 20% or more and 200% or less of the radius R of the cylindrical portion 2. When the length H of the protruding portion 3 is 20% or more of the radius R of the cylindrical portion 2, a space having a sufficient volume is secured between the outer peripheral surface 31 of the protruding portion 3 and the inner peripheral surface of the cylinder sleeve 11. can do. Therefore, it is possible to reduce the amount of the solidified piece 72 that overflows from between the outer peripheral surface 31 of the protruding portion 3 and the inner peripheral surface of the cylinder sleeve 11. Further, when the length H of the protruding portion 3 is 200% or less of the radius R of the cylindrical portion 2, sufficient rigidity of the protruding portion 3 can be ensured.

  Let β be the angle formed by the outer peripheral surface 31 of the protrusion 3 with respect to the axial direction in the axial section of the protrusion 3. The angle β of the outer peripheral surface 31 of the protrusion 3 is preferably 5 degrees or more and 45 degrees or less. When the angle β of the outer peripheral surface 31 of the protruding portion 3 is 5 degrees or more, a space having a sufficient volume can be secured between the outer peripheral surface 31 of the protruding portion 3 and the inner peripheral surface of the cylinder sleeve 11. . Therefore, it is possible to reduce the amount of the solidified piece 72 that overflows from between the outer peripheral surface 31 of the protruding portion 3 and the inner peripheral surface of the cylinder sleeve 11. Moreover, when the angle of the outer peripheral surface 31 of the protrusion 3 is 45 degrees or less, the solidified piece 72 can be reliably captured between the outer peripheral surface 31 of the protrusion 3 and the inner peripheral surface of the cylinder sleeve 11. .

  Let W be the width of the annular end surface 53 of the protrusion 3. The width W of the end face 53 of the protruding portion 3 is preferably 1% or more and 80% or less of the radius R of the cylindrical portion 2. When the width W of the end face 53 of the protruding portion 3 is 1% or more of the radius R of the cylindrical portion 2, the protruding portion 3 can have a strength sufficient to withstand the pressure when the molten metal 70 is pushed out. In addition, since the width W of the end surface 53 of the protruding portion 3 is 80% or less of the radius R of the cylindrical portion 2, a sufficient volume is provided between the outer peripheral surface 31 of the protruding portion 3 and the inner peripheral surface of the cylinder sleeve 11. A space having a sufficient volume can be secured inside the recess 5 as well as a space having the space.

  8, 9 and 10 are sectional views in the axial direction of a plunger tip 1 according to another embodiment of the present invention.

  In the plunger tip 1 of FIG. 8, the outer diameter of the protrusion 3 decreases from the cylindrical portion 2 to the tip so as to follow a concave curve. Thereby, the outer peripheral surface 31 of the protrusion part 3 curves in a concave shape. Further, the inner diameter of the recess 5 decreases from the tip to the bottom 52 along a concave curve. Thereby, the inner peripheral surface 51 of the recess 5 is curved in a concave shape.

  In the plunger tip 1 of FIG. 9, the outer diameter of the protrusion 3 decreases from the cylindrical portion 2 to the tip so as to follow a convex curve. Thereby, the outer peripheral surface 31 of the protrusion part 3 curves in a convex shape. Further, the inner diameter of the recess 5 decreases along the convex curve from the tip to the bottom 52. Thereby, the inner peripheral surface 51 of the recess 5 is curved in a convex shape.

  In the plunger tip 1 of FIG. 10, the outer diameter of the protruding portion 3 decreases stepwise from the cylindrical portion 2 to the tip. Further, the inner diameter of the recess 5 decreases stepwise from the tip to the bottom 52.

  The shape of the outer peripheral surface 31 of the protruding portion 3 of the plunger tip 1 of any of FIGS. 3, 8, 9, and 10 and the concave portion 5 of the plunger tip 1 of any of FIGS. 3, 8, 9, and 10. The shape of the inner peripheral surface 51 may be combined.

  The plunger tip 1 may have a shape different from the shape of the outer peripheral surface 31 of the protrusion 3 in the above embodiment. Moreover, the plunger chip | tip 1 may have a shape different from the shape of the internal peripheral surface 51 of the recessed part 5 in the said embodiment.

  The present invention can be used for producing various cast products by a die casting method.

DESCRIPTION OF SYMBOLS 1 Plunger tip 2 Cylindrical part 3 Protruding part 4 Mounting part 5 Recessed part 10 Injection apparatus 11 Cylinder sleeve 12 Inlet 13 Cylinder rod 14 Drive apparatus 15 Connection member 16 Pipe for cooling water 22 Internal space 23 Opening 24 Mounting hole 24a Female screw 31 Outer peripheral surface 51 Inner peripheral surface 52 Bottom 53 End surface 60 Mold device 61 Movable member 62, 63 Mold member 64 Fixed member 65 Cavity 66 Molten metal supply port 67 Runner 70 Molten metal 71 Solidified layer 72 Solidified piece 100 Die casting apparatus Ax Shaft D Depth H length R radius W width α, β angle ΔR width

Claims (8)

A cylindrical part;
A protrusion provided integrally at one end of the cylindrical portion in the axial direction;
The die casting plunger tip, wherein the protrusion has an outer diameter that gradually decreases from the cylindrical portion to the tip, and a recess is formed at the tip. The depth of the said recessed part in the said axial direction is 5% or more and 200% or less of the radius of the said cylindrical part, The die tip for die-casting of Claim 1 characterized by the above-mentioned. The concave portion has an inner peripheral surface and a bottom portion that are rotationally symmetric with respect to the axis of the cylindrical portion, and an inner diameter of the inner peripheral surface decreases linearly from the tip to the bottom portion, and the axial section of the protruding portion 3. The die casting plunger tip according to claim 1, wherein an angle formed by the inner peripheral surface with respect to the axial direction is not less than 5 degrees and not more than 45 degrees. The difference between the radius of the protruding portion and the radius of the cylindrical portion at the boundary between the cylindrical portion and the protruding portion is 0% to 50% of the radius of the cylindrical portion. The plunger tip for die-casting in any one of -3. The length from the boundary between the cylindrical portion and the protruding portion to the tip of the protruding portion in the axial direction is 20% or more and 200% or less of the radius of the cylindrical portion. 4. The die casting plunger tip according to any one of 4 above. The protrusion has a frustoconical outer peripheral surface, and an angle formed by the outer peripheral surface of the protrusion with respect to the axial direction in the axial section of the protrusion is not less than 5 degrees and not more than 45 degrees. The plunger tip for die casting according to any one of claims 1 to 5. The projecting portion has an annular end surface at the tip, and the width of the end surface in the radial direction is not less than 1% and not more than 80% of the radius of the columnar portion. The plunger tip for die-casting in any one. Attaching a cylinder sleeve to the mold apparatus so as to communicate with a cavity of the mold apparatus, and inserting the die casting plunger tip according to any one of claims 1 to 7 into the cylinder sleeve;
Injecting a molten material into a space between the plunger tip and the mold apparatus in the cylinder sleeve;
And a step of pushing the molten material in the cylinder sleeve into the cavity of the mold apparatus by moving the plunger tip in the cylinder sleeve toward the mold apparatus. .

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