JP4454398B2 - Core for inner molding of receiving port in centrifugal casting machine - Google Patents

Description

  The present invention relates to a receiving port inner surface forming core in a centrifugal casting apparatus.

  As an apparatus for centrifugally casting a cast iron pipe such as a ductile cast iron pipe, an apparatus shown in FIG. Here, reference numeral 1 denotes a centrifugal cast metal frame, which is horizontally supported on a drive roller (not shown) so that it can rotate around the axis 2 at high speed. A ductile cast iron pipe usually has a receiving port having a diameter larger than that of the tube body at one end. Correspondingly, the metal frame 1 also has a larger diameter at one end than the inner diameter of other portions. A receiving port forming portion 3 having a diameter is provided.

  In general, the inner peripheral surface of the receiving port of the cast iron pipe has a complicated shape. In order to form such an inner peripheral surface of the receiving port, a cylindrical metal core 4 as illustrated is used. The metal core 4 includes a flange portion 5 attached to an end portion of the receiving port forming portion 3 of the metal frame 1, and a split core portion 6 disposed coaxially from the flange portion 5 toward the back side of the metal frame 1. And a receiving port 9 of a cast iron pipe 8 that is centrifugally cast with a molten metal supplied to the inside of the metal frame 1 by the outer periphery of the axially protruding portion 7 provided on the flange portion 5 and the split core portion 6. It is comprised so that the internal peripheral surface of may be formed. The divided core portion 6 is divided into a plurality along the circumferential direction, and each divided portion is configured to swing in the radial direction around the pin 10 provided on the flange portion 5.

  Specifically, the metal core 4 has an uneven portion (not shown) for forming a groove on the inner periphery of the receiving port 9 of the cast iron pipe 8 on the outer periphery, or on the inner side of the receiving port 9 on the back side of the receiving port. It is used to form a tapered surface 11 that expands toward the surface, and in the illustrated example, the tapered surface 11 is formed by the divided core portion 6.

  In such a configuration, when the cast iron pipe 8 is centrifugally cast, the horizontal metal frame 1 on which the metal core 4 is mounted is rotated around the axis 2 at a high speed as shown in the figure. Then, due to the centrifugal force acting on the divided core portion 6, the divided core portion 6 is rocked outward in the radial direction along the pin 10, and the core portion 6 is held in an expanded state. If the molten metal is supplied to the inside of the metal frame 1 in this state, the tube 8 is centrifugally cast, and the inner peripheral surface of the receiving port 9 is shaped into a predetermined shape by the axially protruding portion 7 and the divided core portion 6 of the metal core 4. Casted.

When the molten metal has solidified, the rotation of the metal frame 1 is stopped. Then, the split core portion 6 whose diameter has been expanded by the centrifugal force swings around the pin 10 so that the diameter can be reduced, so that the diameter is reduced and the distance from the tapered surface 11 of the receiving port 9 is reduced. By doing so, even if the tapered surface 11 of the cast iron pipe 8 is a so-called reverse tapered surface whose diameter increases toward the inner side of the receiving port, the metal core 4 can be taken out from the receiving port 9 of the formed cast iron tube 8 without any trouble. Can do.
JP 2003-164953 A

  However, since the diameter of the split core portion 6 of the metal core 4 is increased only by the centrifugal force acting on the split core portion 6 as described above, the diameter should not be increased to a predetermined shape in some cases. Can happen. In such a case, when the plurality of pipes 8 are continuously manufactured by centrifugal casting, a gap is formed in the divided portion due to thermal influence or deposition of the coating liquid applied to the metal core 4, and the molten metal enters the gap. There is a risk of casting.

  Further, after casting, the core portion 6 is reduced in diameter depending on the swinging of the divided core portion 6 around the pin 10 based on the action of gravity and the like, so that only insufficient reduction in diameter can be performed. There is no denying the possibility of something happening. In such a case, it becomes impossible to take out the metal core from the receiving port of the cast iron pipe.

  Therefore, the present invention solves such a problem, and when a pipe is centrifugally cast using a metal core having a split core portion, the occurrence of a gap based on a poor expansion of the split core portion is prevented, and the product It aims at making it possible to prevent the occurrence of casting. Another object of the present invention is to make it possible to reliably reduce the diameter of the divided core portion after centrifugal casting so that it can be taken out from the cast iron pipe.

In order to achieve this object, the present invention provides a core mounted to form an inner surface of the receiving port at an end portion on the receiving side of a metal frame for centrifugally casting a tube having a receiving port at one end. A flange portion attached to an end portion on the receiving side of the metal frame, and disposed coaxially from the flange portion toward the interior of the receiving port in the metal frame, and divided into a plurality along the circumferential direction, And it becomes a regular shape by expanding the diameter at the time of casting, and when the casting is finished, it is inserted into the inside of the divided core portion at the time of casting, and the cylindrical divided core portion that can be reduced in diameter from the regular shape, And a core part diameter increasing member that presses the inner periphery of the divided core part in the diameter increasing direction.

Further, in the present invention, in the above, the split core portion is supported so as to be swingable around a plurality of axes provided in a direction perpendicular to the axis of the metal frame and tangential to the circumferential direction of the metal frame , Projections in the same direction as the shaft are formed on the inner side of the split core portion along the radial direction than the shaft and toward the opening side of the metal frame toward the opening side of the metal frame .

  Therefore, according to the present invention, the core portion expanding member is inserted into the divided core portion at the time of casting and the outer peripheral tapered surface is formed by this insertion to press the inner periphery of the divided core portion in the diameter increasing direction. Therefore, the split core portion is not only expanded in diameter by the acting centrifugal force, but also its inner periphery is pressed in the diameter expansion direction by the outer peripheral tapered surface of the core portion expanded member, so that it has a predetermined shape reliably. Therefore, it is possible to prevent the occurrence of a gap due to the poor expansion of the split core portion, and therefore, it is possible to prevent the occurrence of cast burr in the cast iron pipe as a product.

According to the invention, the split core portion is supported so as to be swingable around a plurality of shafts that are provided perpendicular to the axis of the metal frame and tangential to the circumferential direction of the metal frame. Since the protrusion in the same direction as the axis is formed at a position closer to the opening side than the receiving opening on the inner side along the radial direction of the split core portion and toward the opening side of the metal frame, the protrusion is inserted into the metal frame after centrifugal casting. By pulling in the direction away from the center, the split core portion can be swung around the shaft, and the split core portion can be reliably reduced in diameter and taken out from the cast iron pipe.

  In FIG. 1, 20 is a centrifugal cast metal frame, 21 is its axis, and 22 is its receiving port forming part. On the inner periphery of the opening of the receiving port forming portion 22, an outwardly opening tapered surface 23 and a radially inner end surface 24 following the inner end of the tapered surface 23 are formed. 25 is a cast iron pipe formed by supplying molten metal into the metal frame 20, and 26 is a receiving port thereof. On the inner periphery of the receiving port 26, an outwardly open tapered surface 27 is formed at the opening, and gradually toward the inner side of the receiving port 26 on the inner side of the receiving port 26 than the tapered surface 27. A so-called reverse-tapered tapered surface 28 that expands in diameter and a receiving end end surface 29 are formed.

  1 to 6, reference numeral 31 denotes a core for forming an inner surface of a receiving opening according to the present invention. In this core 31, 32 is an annular flange portion made of a heat-resistant metal, and is positioned in a concentric manner with respect to the metal frame 20 by contacting the taper surface 23 on the inner periphery of the metal frame 20. The outer peripheral taper surface 33 and the outer peripheral taper surface 33 in contact with the taper surface 23 of the metal frame 20 are pressed against the back end surface 24 of the metal frame 20, so that the core 31 is axially oriented with respect to the metal frame. It has the end surface 34 for positioning, and the cyclic | annular axial direction protrusion 35 for forming the taper surface 27 of the receptacle 26 of the cast iron pipe 25. As shown in FIG. Reference numeral 36 denotes a space formed in the central portion of the flange portion 32.

As shown in FIGS. 1, 2, and 4, the flange portion 32 has a surface opposite to the surface on which the axial center protrusion 35 is formed, that is, a surface facing the outside of the metal frame 20. A pair of brackets 37 are provided at a plurality of positions along the circumferential direction so as to protrude in the axial direction of the metal frame 20. A plurality of shafts 38 oriented in the direction of the tangent to the pitch circle on which these brackets 37 are arranged, that is, a plurality of shafts 38 provided in a direction perpendicular to the axis of the metal frame 20 on the pitch circle. These are supported by a pair of brackets 37 and 37, respectively.

  Reference numeral 40 denotes a cylindrical divided core portion formed of a heat-resistant metal. The split core portion 40 is divided into a plurality of portions along the circumferential direction, and as shown in FIGS. 5 and 6, a long divided portion 41 having a long circumferential length and a short divided having a short circumferential length. The parts 42 are arranged alternately along the circumferential direction.

As shown in FIG. 1, the split core portion 40 constituted by the long split portion 41 and the short split portion 42 is a portion on the back side of the receiving port 26 with respect to the taper surface 27 of the outer opening in the cast iron pipe 25, that is, A core forming portion 43 for forming a portion including the tapered surface 28 on the back side of the receiving port 26 with respect to the tapered surface 27 is formed integrally with the core forming portion 43, and the core forming portion 43 is made of gold. The arm portion 44 is disposed along the axial direction of the metal frame 20 toward the opening side of the frame 20. The core forming portion 43 includes an inner flange portion 45 for forming the back end surface 29 of the receiving port 26 of the cast iron pipe 25. The arm portion 44 is formed in an L shape, and a tip portion thereof is supported by the shaft 38. In other words, each of the long divided portion 41 and the short divided portion 42 of the divided core portion 40 has the arm portion 44 and is supported by the shaft 38, as shown by a solid line and a virtual line in FIG. The metal frame 20 can be swung in the radial direction about the shaft 38. As a result, the split core portion 40 takes a diameter-enlarged state indicated by a solid line in FIGS. 1 and 2, that is, a regular shape for forming the inner surface of the cast iron pipe 25, and a diameter-reduced state indicated by an imaginary line in FIG. 2. be able to.

As shown in FIGS. 5 and 6, the cross-sectional shapes of the long divided portion 41 and the short divided portion 42 are both trapezoidal. Specifically, the long divided portion 41 is formed in a trapezoid shape with the inner peripheral side being the upper bottom and the outer peripheral side being the lower bottom, and the short divided portion 42 is a trapezoid shape having the inner peripheral side being the lower bottom and the outer peripheral side being the upper bottom. Is formed. As a result, when the diameter is expanded, the long divided portion 41 is expanded first, and when the diameter is reduced, the short divided portion 42 is first reduced in diameter, thereby hindering the diameter expansion and the diameter reduction of the divided core portion 40. It is configured to be able to do without. Then, when the diameter is increased and a regular shape is obtained, each of the long divided portion 41 and the short divided portion 42 has a cross-sectional shape that comes into contact with each other without any gap in the circumferential direction.

Further, as shown in FIGS. 1 and 2, the split core portion 40 is configured to be able to come into contact with the tip end of the axial-direction protruding portion 35 when the diameter is expanded to a normal state. Thereby, the axial direction protrusion part 35 and the division | segmentation core part 40 are positioned mutually, and the inner surface of the receiving port 26 of the cast iron pipe 25 can be correctly cast now.

  As shown in FIGS. 1, 2, and 4, the longer divided portion 41 of the divided core portion 40 and the arm portion 44 of the shorter divided portion 42 are located on the inner side in the radial direction of the divided core portion 40 than the shaft 38. In this position, protrusions 46 in the same direction as the shaft 38 are formed so as to protrude from both sides of the arm portion 44, respectively.

  As shown in FIGS. 1 and 2, a metal disk-like plate 48 is coaxially attached to the flange portion 32, and a metal hollow sleeve 49 is integrally provided on the plate 48. . Specifically, bolts 50 in a direction parallel to the axis 21 and away from the metal frame 20 are implanted and fixed to the flange portion 32 at a plurality of positions along the circumferential direction. The head 51 is arranged at a position spaced from the flange 32 of the implanted bolt 50. As shown in FIGS. 1 to 3, the plate 48 is formed with a through hole 52 through which the bolt 50 is inserted, and the bolt 50 is inserted into the flange portion 32 after passing through the through hole 52 as shown in the figure. Accordingly, the plate 48 is movable in the direction of the axis 21 between the flange portion 32 and the head portion 51 of the bolt 50. When the plate 48 is attached to the flange portion 32 in such a manner that the plate 48 is movable in the direction of the axis 21 as described above, interference with the bracket 37, the shaft 38, and the arm portion 44 of the split core portion 40 is caused. Radial cutouts 53 are formed to avoid this.

  The sleeve 49 is provided concentrically at the center of the plate 48, and the outer periphery of the sleeve 49 is welded to the inner peripheral edge 54 of the plate 48 at a portion other than the notch 53. And integrated.

  The sleeve 49 is disposed concentrically with the shaft center 21 from the plate 48 toward the inside of the split core portion 40, and the tip end side of the tip portion 55 is made of gold more than the inner flange portion 45 at the tip end of the split core portion 40. It protrudes to a position on the back side of the frame 20. An external thread 56 is formed on the outer periphery of the distal end portion 55 of the sleeve 49. An annular metal core diameter increasing member 57 is screwed onto the outer screw 56. 58 is a metal retaining nut that is screwed onto the sleeve 49 together with the core diameter-expanding member 57 to position the core diameter-expanding member 57 in the length direction of the sleeve 49, that is, in the direction of the axis 21. The double nut for fixing to 49 is comprised. A tapered surface 59 is formed on the outer periphery of the core diameter increasing member 57 so as to decrease in diameter toward the inner side of the opening forming portion 22 of the metal frame 20. A tapered surface 60 corresponding to the tapered surface 59 is formed on the inner periphery of the inner flange portion 45 of the split core portion 40. The angle formed by the taper surface 59 of the core diameter-expanding member 57 and the axis 21 is configured to be equal to or smaller than the angle formed by the taper surface 60 of the inner flange 45 and the axis 21. .

  Further, the sleeve 49 is also provided in a direction away from the metal frame 20 rather than the plate 48, and a tip portion thereof is coupled to a pressing portion 63 of the core setter via a bearing 62. The pressing portion 63 is rotatable with respect to the sleeve 49 and moves the sleeve 49 together with the plate 48 in the direction of the axis 21 until the plate 48 hits the flange portion 32 and the head portion 51 of the bolt 50. In particular, the distal end portion 55 of the sleeve 49 can be moved toward the back side of the opening forming portion 22 of the metal frame 20.

  For example, when the sleeve 49 is pushed into the receiving port forming portion 22 until the plate 48 hits the flange portion 32 by the pressing portion 63, the tapered surface 59 of the core portion diameter increasing member 57 becomes the inner flange portion of the split core portion 40. The core portion enlarged member 57 is pre-positioned with respect to the sleeve 49 and fixed by the lock nut 58 so that the divided core portion 40 can be expanded in a normal state by acting on the taper surface 60 of 45. Keep it.

  In such a configuration, when the cast iron pipe 25 is centrifugally cast by the metal frame 20 using the core 31, first, the split core portion 40 of the core 31 that is not attached to the metal frame 20 is first attached to an appropriate jig or the like. Then, a coating material is applied to the outer peripheral surface and a predetermined portion of the flange portion 32.

  Next, the diameter-expanded state of the split core portion 40 is released, and the core 31 together with the sleeve 49 and the plate 48 is moved by the pressing portion 63 of the core setter and attached to the metal frame 20. When the metal frame 20 is rotated around the axis 21 at a high speed while the flange portion 32 of the core 31 is pressed and fixed to the metal frame 20 by the stopper 65 shown in FIG. Then, the split core portion 40 is expanded in diameter by centrifugal force as shown in FIG.

  Further, the sleeve 49 is pushed into the divided core portion 40 by the pressing portion 63 until the plate 48 contacts the flange portion 32. Then, a diameter expansion force is applied to the inner flange portion 45 of the split core portion 40 by the action of the tapered surface 59 of the core portion diameter increasing member 57. At this time, the sleeve 49 also rotates together with the rotation of the core 31, but the pressing portion 63 does not rotate together with the sleeve 49 due to the action of the bearing 62.

  As a result, the divided core portion 40 is expanded in diameter by the acting centrifugal force, and is also expanded by the core diameter-expanding member 57, so that the diameter is surely expanded to a predetermined shape. For this reason, generation | occurrence | production of the clearance gap based on the diameter expansion defect of the division | segmentation core part 40 can be prevented.

  Therefore, while maintaining this state, the pouring trough is inserted from the insertion port forming portion of the metal frame 20 to the vicinity of the receiving port forming portion 22, and the molten metal is supplied from the tip of the pouring trough to the inner periphery of the metal frame 20. Then, the tube 25 is centrifugally cast. The inner peripheral surface of the receiving port 26 of the tube 25 is formed by the outer peripheral surface of the axially protruding portion 35 of the flange portion 32 and the split core portion 40.

  At this time, since the generation of the gap based on the diameter expansion failure of the split core portion 40 is prevented as described above, it is possible to reliably prevent the occurrence of cast burr in the cast iron pipe 25 as a product. Further, the angle formed by the tapered surface 59 of the core diameter-expanding member 57 and the shaft center 21 is configured to be equal to or smaller than the angle formed by the tapered surface 60 of the inner flange 45 and the shaft center 21. Therefore, it is possible to prevent the molten metal from entering the gap between the inner periphery of the inner flange 45 and the outer periphery of the core portion enlarged member 57.

  When the casting of the cast iron pipe 25 by the pouring operation is completed, the rotation of the metal frame 20 is stopped, and the direction in which the plate 48 is separated from the flange portion 32 by the pressing portion 63, that is, the metal frame 20 as shown in FIG. The sleeve 49 is moved in the direction of exiting from the receiving port forming portion 22. Then, the core portion diameter increasing member 57 is separated from the inner flange portion 45 of the split core portion 40, whereby the split core portion 40 can be reduced in diameter by gravity or other action, and by reducing the diameter, a so-called reverse taper is obtained. The core 31 can be easily extracted from the cast iron tube 25 having the tapered surface 28 and removed from the metal frame 20.

In some cases, the cast iron pipe 25 may seize on the split core portion 40 of the core 31 at the time of casting. If no countermeasure is taken in such a case, the split core portion 40 will not be reduced in diameter and cannot be extracted. However, as described above, the arm portion 44 of the split core portion 40 has the projection 46 in the same direction as the shaft 38 at the inner position along the radial direction of the split core portion 40 than the shaft 38. Since the projections 46 are pulled in the direction away from the metal frame 20 in the order of the short division portion 42 and the long division portion 41, the division core portion 40 is moved around the shaft 38 . The diameter can be forcibly reduced without any problem by swinging.

It is sectional drawing which shows a mode that the core for receiving port inner surface shaping | molding in the centrifugal casting apparatus of embodiment of this invention was mounted | worn with the centrifugal casting metal frame. FIG. 2 is an exploded view of a core for forming an inner surface of a receptacle in FIG. 1. It is a side view of the plate in the same core. It is a left view of the principal part of the core in FIG. It is a right view of the principal part of the core in FIG. It is a perspective view of the part shown by FIG. It is a figure which shows a mode that the division | segmentation core part in FIG. 1 is diameter-reduced. It is sectional drawing which shows a mode that the core for receiving port inner surface shaping | molding in the conventional centrifugal casting apparatus was mounted | worn with the centrifugal casting metal frame.

Explanation of symbols

DESCRIPTION OF SYMBOLS 20 Centrifugal cast metal frame 22 Receptacle forming part 25 Cast iron pipe 26 Receptacle 31 Core 32 Flange part 40 Divided core part 48 Plate 49 Sleeve 57 Core part diameter expansion member

Claims (2)

A core mounted to form an inner surface of the receiving port at an end of the receiving side of a metal frame for centrifugally casting a tube having a receiving port at one end;
A flange portion to be attached to an end portion on the receiving side of the metal frame;
While being coaxially arranged from the flange part toward the inner depth of the receiving port in the metal frame, it is divided into a plurality along the circumferential direction and becomes a regular shape by expanding the diameter during casting, and casting is completed. A cylindrical split core that can be reduced in diameter from a regular shape,
A core part diameter increasing member inserted into the divided core part at the time of casting and pressing the inner periphery of the divided core part in the diameter increasing direction;
A core for forming an inner surface of a receiving port in a centrifugal casting apparatus. The split core portion is supported so as to be swingable around a plurality of shafts that are perpendicular to the axis of the metal frame and tangential to the circumferential direction of the metal frame . 2. The receiving in a centrifugal casting apparatus according to claim 1, wherein a projection in the same direction as the shaft is formed at a position on the inner side along the radial direction and toward the opening side of the metal frame and on the opening side of the receiving port. Mouth inner surface molding core.

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