A mould and process for casting a cast iron insert ring with a cavity

Abstract

The present application relates to the technical fields of metal casting, in particular to a mold and process for casting iron insert ring with cavity, comprising: a lower mold, the inner cavity of the lower mold is stacked with multiple shaping rings from bottom to top, the side of the shaping ring is set as "<" shape; the annular pipe is composed of two arc pipes which are spliced with each other, the middle part of the surface of the arc pipe is fixed with a positioning block; the upper part of the lower mold is provided with an upper mold, the upper mold covers the upper end opening of the lower mold and is pressed tightly; the beneficial effects are: multiple shaping rings are stacked from bottom to top in the middle part of the inner cavity of the lower mold, the annular pipe is located between the upper and lower adjacent two shaping rings, and a gap is left between the annular pipe and the shaping ring, the side wall of the shaping ring is "<" shape, and the side wall is inwardly recessed to form a quarter circular arc shape, so that the cast iron insert ring formed by the present device can be completely wrapped outside the annular pipe, the contact area between the two is maximized, and the overall strength is effectively improved.

Description

Technical Field

[0001] This invention relates to the field of metal casting technology, specifically to a mold and process for casting a cavity cast iron insert ring. Background Technology

[0002] A hollow cast iron insert is a special cast iron bushing that is pressed into the most critical part of an aluminum alloy piston (i.e., the piston head ring groove). Its internal design has a hollow cavity located at the first ring groove on the top of the piston, which gives the cast iron insert a certain "elasticity" to solve the thermal stress problem. In addition, the cavity removes excess material, which can significantly reduce the weight of the insert.

[0003] In the prior art, Chinese invention with publication number CN112756586B discloses a mold and process method for casting a cavity-type cast iron insert ring. The metallurgical bond between the annular heat-resistant stainless steel tube ring and the cast iron insert ring is achieved by insert casting, which can ensure that the metallographic structure of the cast iron insert ring is high-temperature austenite. It does not require welding of each cast iron insert ring and steel tube ring around the circumference, which can significantly improve the convenience of manufacturing. Moreover, the manufacturing process method is low in cost and has a high yield.

[0004] Currently, traditional cast iron inserts and annular steel pipes only have partial contact and bonding, resulting in insufficient connection strength. Over prolonged use, there is a risk of detachment between the annular steel pipe and the cast iron insert, thus affecting service life. Therefore, this invention proposes a mold and process for casting hollow cast iron inserts to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide a mold and process for casting a cavity-type cast iron insert ring, so as to solve the problems of limited contact area and insufficient connection strength between the cast iron insert ring and the annular steel pipe mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a mold for casting a cavity-type cast iron insert ring, comprising:

[0007] The lower mold has multiple shaping rings stacked from bottom to top in its inner cavity. The sides of the shaping rings are shaped like a "<" and are concave inward to form a quarter-circle arc. The outer edge of the shaping rings is covered with a protective ring. An annular tube is provided between two adjacent shaping rings. Multiple annular tubes and multiple protective rings are distributed sequentially at intervals. A gap is left between the surface of the annular tube and the side of the shaping ring.

[0008] The annular tube is composed of two arc-shaped tubes spliced ​​together. A positioning block is fixed in the middle of the surface of the arc-shaped tube, and the side of the positioning block abuts against the inner wall of the lower mold. A support column is fixedly installed through the middle of the positioning block, and two adjacent support columns are connected to each other by insertion.

[0009] An upper mold is provided above the lower mold, and the upper mold covers the upper opening of the lower mold and presses it tightly.

[0010] Preferably, the upper end of the support column is provided with a positioning slot, and the lower end of the support column is fixedly provided with a positioning insert that matches the positioning slot. One end of the arc-shaped tube is provided with a docking groove, and the other end of the arc-shaped tube is fixed with a docking ring that matches the docking groove. The two arc-shaped tubes are centrally symmetrically distributed, and the docking ring and the docking groove are inserted into each other in a corresponding manner.

[0011] Preferably, an upper retaining ring and a lower retaining ring are respectively provided at the upper opening and the bottom of the inner cavity of the lower mold. A stepped hole is provided through the bottom of the lower mold. The lower retaining ring is located in the inner cavity at the opening end of the stepped hole and is adapted to it. The upper mold is annular and presses the upper retaining ring from top to bottom. The upper retaining ring, the shaping ring and the lower retaining ring are concentric.

[0012] Preferably, a cooling cylinder is provided in the middle of the inner cavity of the lower mold, and the lower end of the cooling cylinder movably passes through the inner cavity of the stepped hole. The upper retaining ring, the shaping ring and the lower retaining ring are all movably sleeved on the outside of the cooling cylinder and adapted to it. The upper end of the cooling cylinder movably passes through the middle of the upper mold and extends to the top of the upper mold.

[0013] Preferably, a lower pressure ring is provided on the upper side of the upper mold, and a plurality of lower pressure columns arranged in a ring array are fixedly connected to the lower surface of the lower pressure ring. The lower pressure columns movably penetrate the upper mold and abut against the upper surface of the upper retaining ring. The lower pressure ring and the upper mold are locked together by fastening bolts. Both the side wall of the lower mold and the side wall of the upper mold are fixed with connecting bosses, and two adjacent connecting bosses are fixedly connected by bolts.

[0014] Preferably, the inner cavity of the cooling cylinder is provided with an inner cylinder concentric with it, and the upper ends of the two are fixedly connected. A flow guide baffle is fixedly provided in the gap between the cooling cylinder and the inner cylinder. The flow guide baffle is spiral in shape. There are two sets of flow guide baffles, and an upward flow channel and a downward flow channel are formed between the two sets of flow guide baffles. The upward flow channel and the downward flow channel are interconnected in the upper region between the cooling cylinder and the inner cylinder. The lower ends of the upward flow channel and the lower ends of the downward flow channel are both connected to circulation pipes. The two circulation pipes are respectively connected to the inlet and outlet of the external cooling circulation pump.

[0015] Preferably, the lower mold is placed on the upper surface of the support base, a limiting ring is fixed on the outer side of the cooling cylinder, the lower end of the cooling cylinder is inserted into the inside of the support base and the limiting ring fits against the upper surface of the support base, a rotating platform is rotatably installed on the lower end of the outer side wall of the lower mold, and a notch groove located directly below the rotating platform is opened at the corner of the support base.

[0016] Preferably, the lower outer wall of the lower mold has a receiving groove at its lower end, and the receiving groove is semi-circular. The bottom of the receiving groove has a casting inlet that communicates with the inner cavity of the lower mold. Half of the rotating platform is located in the inner cavity of the receiving groove, and the other half is located outside the receiving groove. The interior of the rotating platform has a U-shaped casting connection channel. The outer side of the lower mold is fixedly installed with a casting pipe by a bracket. The lower end face of the casting pipe is attached to the upper surface of the rotating platform. The two ends of the casting connection channel are respectively connected to the lower opening of the casting pipe and the casting inlet.

[0017] Preferably, a bottom cover is provided at the lower opening of the receiving trough, and the bottom cover is fixedly connected to the lower mold by bolts. A circular boss is fixedly provided on the upper surface of the bottom cover. The circular boss is inserted into the middle of the rotating platform and rotatably connected to it. A slag discharge hole is provided through the inner wall of the casting connection channel, and the slag discharge hole is offset from the center of the rotating platform. A slag discharge port is provided through the surface of the circular boss, and the slag discharge port is offset from the center of the circular boss. A slag discharge hole is provided through the surface of the rotating platform. After the rotating platform rotates 90 degrees, the slag discharge hole is connected to the slag discharge port and the slag discharge hole is connected to the casting pipe.

[0018] A process for casting a cavity-shaped cast iron insert ring, using the aforementioned mold, specifically includes the following steps:

[0019] Step 1: Pass the cooling cylinder through the inner cavity of the lower mold. Place the lower mold on the upper surface of the support base and insert the lower end of the cooling cylinder into the support base. Stack multiple shaping rings and multiple annular tubes in the inner cavity of the lower mold in sequence at intervals. Place the lower retaining ring and the upper retaining ring at the bottom and upper opening of the inner cavity of the lower mold, respectively. Cover the upper opening of the lower mold with the upper mold and lock the two together with bolts.

[0020] Step 2: Adjust the fastening bolts to press down the lower pressure ring, so that the lower end of the lower pressure column presses down and tightens against the upper retaining ring;

[0021] Step 3: Add molten metal into the inner cavity of the casting pipe. The molten metal passes through the casting connection channel and the casting inlet and is injected into the inner cavity of the lower mold until the inner cavity of the lower mold is filled.

[0022] Step 4: Rotate the rotary table 90 degrees so that the lower opening of the pouring inlet is blocked by the surface of the rotary table. The slag discharge hole 1 is connected to the slag discharge port, and the slag discharge hole 2 is connected to the pouring pipe. At this time, the excess molten liquid in the inner cavity of the pouring pipe and the inner cavity of the pouring connection channel is discharged from the slag discharge hole 2 and the slag discharge port, respectively.

[0023] Step 5: After the molten metal in the lower mold cavity solidifies, a cast iron insert ring is formed. The cast iron insert ring, along with multiple shaping rings and multiple annular tubes, is taken out together. Annular flanges are cut and formed on the outside of the cast iron insert ring. Then, horizontal cuts are made between two adjacent annular tubes. Finally, the shaping rings are separated from the cast iron insert ring.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] This invention features multiple shaping rings stacked from bottom to top in the inner cavity of the lower mold. An annular tube is positioned between two adjacent shaping rings, with a gap between the annular tube and the shaping rings. The annular tube is composed of two arc-shaped tubes joined together. A positioning block is fixed to the surface of the arc-shaped tube and rests against the inner wall of the lower mold. A support column is fixedly installed through the center of the positioning block. Two adjacent support columns are interlocked to achieve the suspended positioning of the annular tube. The sidewall of the shaping ring is shaped like a "<" and is concave inward to form a quarter-circle arc. This allows the cast iron inlay ring, after being cast, to completely cover the outside of the annular tube, maximizing the contact area between the two and effectively improving the overall strength. Attached Figure Description

[0026] Figure 1 This is a three-dimensional schematic diagram of the overall structure of the present invention;

[0027] Figure 2 This is a schematic diagram of the internal structure of the mold of the present invention;

[0028] Figure 3 This is a schematic diagram showing the demolding process after the cast iron insert ring of the present invention has been formed;

[0029] Figure 4 This is a three-dimensional schematic diagram of the arc-shaped tube structure of the present invention;

[0030] Figure 5 This is a schematic diagram of the cast iron inlay ring covering the annular tube according to the present invention;

[0031] Figure 6 This is a three-dimensional schematic diagram of the cast iron inlaid ring structure of the present invention after cutting;

[0032] Figure 7 This is a schematic diagram showing the connection between the shaping ring and the cooling cylinder structure of the present invention;

[0033] Figure 8 This is a partial cross-sectional view of the cooling cylinder structure of the present invention;

[0034] Figure 9 This is an exploded view of the lower pressure ring and upper mold structure of the present invention;

[0035] Figure 10 This is an exploded view of the rotating platform and bottom cover structure of the present invention;

[0036] Figure 11 This is a schematic diagram of the internal structure of the rotary table of the present invention.

[0037] In the diagram: 1. Support base; 11. Notch; 2. Lower mold; 21. Stepped hole; 22. Collection slot; 23. Casting inlet; 24. Bottom cover; 241. Circular boss; 25. Slag discharge port; 3. Upper mold; 31. Lower pressure ring; 32. Lower pressure column; 33. Fastening bolt; 34. Connecting boss; 4. Cooling cylinder; 41. Circulation pipe; 42. Inner cylinder; 43. Flow guide baffle; 431. Upward flow channel; 432. Downward flow channel; 44. Limiting ring; 5. Casting pipe; 6. Rotary table; 61. Casting connection channel; 62. Slag discharge hole one; 63. Slag discharge hole two; 7. Ring pipe; 71. Arc pipe; 72. Positioning block; 721. Support column; 722. Positioning slot; 723. Positioning platform; 73. Docking groove; 74. Docking ring; 8. Shaping ring; 81. Protective ring; 82. Upper retaining ring; 83. Lower retaining ring; 9. Cast iron inlay ring; 91. Annular flange. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of the present invention clear and complete, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only some, not all, embodiments of the present invention, and are merely illustrative of the embodiments of the present invention. They are not intended to limit the embodiments of the present invention. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] Please see Figures 1 to 11 The present invention provides a technical solution:

[0040] Example 1: A mold for casting a cavity-type cast iron insert ring, comprising: a lower mold 2.

[0041] Specifically, multiple shaping rings 8 are stacked from bottom to top in the inner cavity of the lower mold 2. The sides of the shaping rings 8 are shaped like a "<" and are concave inward to form a quarter-circle arc. Figure 2As shown, multiple shaping rings 8 are stacked sequentially and support each other. The sidewalls of two adjacent shaping rings 8 are joined to form an annular groove with a semi-circular cross-section. A protective ring 81 covers the outer edge of the shaping ring 8, protecting the annular edge in the middle of the side of the shaping ring 8. The shaping ring 8 is made of ceramic, possessing high hardness, high temperature resistance, and good thermal conductivity. This device can form a cast iron inlaid ring 9 by pouring molten metal into the inner cavity of the mold 2. Due to the concave sidewalls of the shaping ring 8, the inner surface of the cast iron inlaid ring 9 is semi-circular after forming. The protective ring 81 is made of ceramic fiber material, capable of... High temperature resistance, easy cutting, and low price make them suitable for use as consumables. Since the formed cast iron insert 9 comprises multiple units, individual cast iron inserts 9 can be obtained by cutting along the protective ring 81. During the cutting process, the protective ring 81, as a consumable, can protect the shaping ring 8, preventing it from being damaged and ensuring its reuse. Furthermore, annular tubes 7 are provided between adjacent shaping rings 8, with multiple annular tubes 7 and multiple protective rings 81 spaced apart. A gap is left between the surface of the annular tubes 7 and the side of the shaping ring 8. Figure 2 and Figure 3 As shown, after the cast iron insert ring 9 is formed, it can cover the outside of the annular tube 7, so that the contact area between the two reaches the maximum, thereby effectively improving the connection strength between the two.

[0042] Secondly, the annular tube 7 is composed of two arc-shaped tubes 71 spliced ​​together. The arc-shaped tube 71 is formed by bending a columnar steel tube in the prior art, which is easy to pre-process. A positioning block 72 is fixed in the middle of the surface of the arc-shaped tube 71, and the side of the positioning block 72 abuts against the inner wall of the lower mold 2. After the positioning block 72 abuts against the inner wall of the lower mold 2, it can position the annular tube 7 in the horizontal direction and prevent the annular tube 7 from shifting in the horizontal direction. A support column 721 is fixedly and through the middle of the positioning block 72. Two adjacent support columns 721 are interlocked and connected. The support column 721 is used to support the annular tube 7 as a whole and ensure that the annular tube 7 can be suspended. When the cast iron inlaid ring 9 is formed, the cast iron inlaid ring 9 can cover the positioning block 72 and the support column 721 together, thereby further improving the connection strength between the annular tube 7 and the cast iron inlaid ring 9.

[0043] Furthermore, an upper mold 3 is provided above the lower mold 2. The upper mold 3 covers the upper opening of the lower mold 2 and presses it tightly. The upper mold 3 is mainly used to prevent the molten metal in the inner cavity of the lower mold 2 from leaking.

[0044] To splice and position the annular tube 7, this application also includes a positioning slot 722 at the upper end of the support column 721 and a positioning insert 723 adapted to the positioning slot 722 fixed at the lower end of the support column 721. The positioning insert 723 and the positioning slot 722 are interlocked to prevent the two adjacent annular tubes 7 from rotating and misaligning. A docking groove 73 is provided at one end of the arc-shaped tube 71, and a docking ring 74 adapted to the docking groove 73 is fixed at the other end of the arc-shaped tube 71. The two arc-shaped tubes 71 are centrally symmetrically distributed, and the docking ring 74 and the docking groove 73 are interlocked. The docking groove 73 and the docking ring 74 cooperate with each other to ensure that the two arc-shaped tubes 71 will not be misaligned and to ensure the overall structural stability of the annular tube 7.

[0045] To ensure that the two adjacent shaping rings 8 remain tightly pressed together, this application further includes an upper retaining ring 82 and a lower retaining ring 83 respectively provided at the upper opening and bottom of the inner cavity of the lower mold 2. A stepped hole 21 is provided through the bottom of the lower mold 2, and the lower retaining ring 83 is located in and fits into the inner cavity of the opening end of the stepped hole 21. The upper mold 3 is annular, and the upper mold 3 presses against the upper retaining ring 82 from top to bottom. The upper retaining ring 82, the shaping ring 8, and the lower retaining ring 83 are concentric. Figure 2 and Figure 3 As shown, the lower retaining ring 83 and the upper retaining ring 82 are mainly used to raise the shaping ring 8 and to press the shaping ring 8 tightly, so as to avoid gaps between two adjacent shaping rings 8 that could lead to leakage of molten metal.

[0046] To prevent the shaping ring 8 from shifting horizontally, this application also includes a cooling cylinder 4 located in the middle of the inner cavity of the lower mold 2, with the lower end of the cooling cylinder 4 movably penetrating through the inner cavity of the stepped hole 21. The upper retaining ring 82, the shaping ring 8, and the lower retaining ring 83 are all movably sleeved on the outside of the cooling cylinder 4 and adapted to it. The cooling cylinder 4 is mainly used to position the multiple shaping rings 8 and prevent the shaping rings 8 from shifting horizontally. The upper end of the cooling cylinder 4 movably penetrates through the middle of the upper mold 3 and extends above the upper mold 3. The contact joint between the upper mold 3 and the cooling cylinder 4 is kept sealed. The cooling cylinder 4 can be removed separately from the middle of the lower mold 2 and the upper mold 3.

[0047] To adjust the clamping force between two adjacent shaping rings 8, this application also includes a lower pressure ring 31 provided on the upper side of the upper mold 3. A plurality of lower pressure columns 32 arranged in a ring array are fixedly connected to the lower surface of the lower pressure ring 31. The lower pressure columns 32 movably pass through the upper mold 3 and abut against the upper surface of the upper retaining ring 82. The lower pressure ring 31 and the upper mold 3 are locked together by fastening bolts 33. By turning the fastening bolts 33, the vertical height position of the lower pressure ring 31 can be adjusted, thereby changing the downward pressure generated by the lower pressure columns 32 on the upper retaining ring 82, and thus adjusting the clamping force between two adjacent shaping rings 8. Connecting bosses 34 are fixed on the side walls of the lower mold 2 and the side walls of the upper mold 3, and two adjacent connecting bosses 34 are fixedly connected by bolts. The connecting bosses 34 and bolts are used to connect the upper mold 3 and the lower mold 2. By loosening the bolts on the connecting bosses 34, the upper mold 3 and the lower mold 2 can be opened.

[0048] To cool the cast iron insert ring 9, this application further includes an inner cylinder 42 concentric with the cooling cylinder 4, with their upper ends fixedly connected. A flow guide baffle 43 is fixedly installed in the gap between the cooling cylinder 4 and the inner cylinder 42. The flow guide baffle 43 is spiral-shaped, and two sets of flow guide baffles 43 are provided, forming an upward flow channel 431 and a downward flow channel 432 between the two sets of flow guide baffles 43. The upward flow channel 431 and the downward flow channel 432 are interconnected in the upper region between the cooling cylinder 4 and the inner cylinder 42. Figure 8 As shown, the cooling medium between the cooling cylinder 4 and the inner cylinder 42 can flow spirally upward in the inner cavity of the downward flow channel 432, and the cooling medium flows spirally downward in the inner cavity of the upward flow channel 431. The lower ends of the upward flow channel 431 and the lower ends of the downward flow channel 432 are both connected to circulation pipes 41. The two circulation pipes 41 are respectively connected to the inlet and outlet of the external cooling circulation pump. When the external cooling circulation pump is working, it is used to drive the cooling medium to circulate in the gap between the cooling cylinder 4 and the inner cylinder 42, so as to realize the cooling and heat exchange of the shaping ring 8, and thus be able to cool and reduce the temperature of the cast iron insert ring 9 in time after it is formed.

[0049] In order to place the lower mold 2 and the cooling cylinder 4, the lower mold 2 of this application is placed on the upper surface of the support base 1. A limiting ring 44 is fixed on the outer side of the cooling cylinder 4. The lower end of the cooling cylinder 4 is inserted into the support base 1 and the limiting ring 44 is attached to the upper surface of the support base 1. The limiting ring 44 is set to prevent the cooling cylinder 4 from moving downward. A rotating table 6 is rotatably installed on the lower end of the outer side wall of the lower mold 2. A notch 11 located directly below the rotating table 6 is opened at the corner of the support base 1. A collecting cylinder is placed in the notch 11 to collect excess molten metal.

[0050] To pour molten metal into the inner cavity of the lower mold 2 to form the cast iron insert ring 9, this application further includes a receiving groove 22 formed at the lower end of the outer side wall of the lower mold 2. The receiving groove 22 is semi-circular, and a pouring inlet 23 communicating with the inner cavity of the lower mold 2 is formed at the bottom of the receiving groove 22. Half of the rotating platform 6 is located inside the receiving groove 22, and the other half is located outside the receiving groove 22. A U-shaped pouring connection channel 61 is formed inside the rotating platform 6. A pouring pipe 5 is fixedly installed on the outer side of the lower mold 2 by a bracket, and the lower end face of the pouring pipe 5 is attached to the rotating platform. On the upper surface of 6, the two ends of the casting connection channel 61 are connected to the lower opening of the casting pipe 5 and the casting inlet 23 respectively. The casting pipe 5, the casting connection channel 61 and the casting inlet 23 form a communicating vessel structure. By pouring molten metal into the inner cavity of the casting pipe 5, the molten metal can pass through the inner cavity of the casting connection channel 61 and the casting inlet 23 in sequence and enter the inner cavity of the lower mold 2 to cast the cast iron insert ring 9. The rotating table 6 itself can rotate. After rotation, the lower opening of the casting inlet 23 is blocked, thereby preventing the molten metal from leaking from the inner cavity of the lower mold 2.

[0051] To drain excess molten metal from the inner cavity of the casting pipe 5 and the casting connection channel 61, this application further includes a bottom cover 24 at the lower opening of the receiving tank 22, which is fixedly connected to the lower mold 2 by bolts. A circular boss 241 is fixedly provided on the upper surface of the bottom cover 24, which is inserted into the middle of the rotating platform 6 and rotatably connected to it. The bottom cover 24 and the circular boss 241 are used to install and position the rotating platform 6, ensuring that the rotating platform 6 can only rotate. A slag discharge hole 62 is provided through the inner wall of the casting connection channel 61, and the slag discharge hole 62 is offset from the center of the rotating platform 6. A slag discharge hole 62 is provided through the surface of the circular boss 241. The slag outlet 25 and the slag discharge outlet 25 are misaligned with the center of the circular boss 241. The surface of the rotating table 6 is provided with a second slag discharge hole 63. After the rotating table 6 rotates 90 degrees, the first slag discharge hole 62 is connected to the slag discharge outlet 25 and the second slag discharge hole 63 is connected to the casting pipe 5. After the molten metal is poured, the casting inlet 23 can be blocked by rotating the rotating table 6. After the first slag discharge hole 62 is connected to the slag discharge outlet 25, the molten metal in the inner cavity of the casting connection channel 61 can be automatically discharged through the slag discharge outlet 25 under the action of gravity. At the same time, the molten metal in the inner cavity of the casting pipe 5 can be automatically discharged from the second slag discharge hole 63. The discharged molten metal falls into the collection cylinder placed below.

[0052] This invention also discloses a process for casting a hollow cast iron insert ring, using the aforementioned mold, specifically including the following steps:

[0053] Step 1: Pass the cooling cylinder 4 through the inner cavity of the lower mold 2. Place the lower mold 2 on the upper surface of the support base 1 and insert the lower end of the cooling cylinder 4 into the support base 1. Stack multiple shaping rings 8 and multiple annular tubes 7 in the inner cavity of the lower mold 2 in sequence at intervals. Place the lower retaining ring 83 and the upper retaining ring 82 at the bottom and upper opening of the inner cavity of the lower mold 2, respectively. Cover the upper mold 3 at the upper opening of the lower mold 2 and lock the two together with bolts.

[0054] Step 2: Adjust the fastening bolt 33 to press down the lower pressure ring 31, so that the lower end of the lower pressure column 32 presses down and tightens against the upper retaining ring 82;

[0055] Step 3: Add molten metal into the inner cavity of the casting pipe 5. The molten metal passes through the casting connection channel 61 and the casting inlet 23 and is injected into the inner cavity of the lower mold 2 until the inner cavity of the lower mold 2 is filled.

[0056] Step 4: Rotate the rotary table 6 ninety degrees so that the lower opening of the casting inlet 23 is blocked by the surface of the rotary table 6. The slag discharge hole 1 62 is connected to the slag discharge port 25, and the slag discharge hole 2 63 is connected to the casting pipe 5. At this time, the excess molten liquid in the inner cavity of the casting pipe 5 and the inner cavity of the casting connection channel 61 is discharged from the slag discharge hole 2 63 and the slag discharge port 25 respectively.

[0057] Step 5: After the molten metal in the inner cavity of the lower mold 2 solidifies, a cast iron insert ring 9 is formed. The cast iron insert ring 9, together with multiple shaping rings 8 and multiple annular tubes 7, is taken out. An annular flange 91 is cut and formed on the outside of the cast iron insert ring 9. Then, a horizontal cut is made between two adjacent annular tubes 7. Finally, the shaping ring 8 is separated from the cast iron insert ring 9.

[0058] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A mold for casting a cavity-shaped cast iron insert ring, characterized in that: include: The lower mold (2) has multiple shaping rings (8) stacked from bottom to top in its inner cavity. The side of the shaping ring (8) is set in the shape of a "<" and the side is concave inward to form a quarter circle arc. The outer edge of the shaping ring (8) is covered with a protective ring (81). An annular tube (7) is set between two adjacent shaping rings (8). Multiple annular tubes (7) and multiple protective rings (81) are distributed in sequence at intervals. A gap is left between the surface of the annular tube (7) and the side of the shaping ring (8). The annular tube (7) is composed of two arc-shaped tubes (71) spliced ​​together. A positioning block (72) is fixed in the middle of the surface of the arc-shaped tube (71), and the side of the positioning block (72) abuts against the inner wall of the lower mold (2). A support column (721) is fixedly installed through the middle of the positioning block (72), and two adjacent support columns (721) are connected to each other by insertion. An upper mold (3) is provided above the lower mold (2), and the upper mold (3) covers the upper opening of the lower mold (2) and presses it tightly.

2. The mold for casting a cavity-type cast iron insert ring according to claim 1, characterized in that: The upper end of the support column (721) is provided with a positioning slot (722), and the lower end of the support column (721) is fixedly provided with a positioning insert (723) that is compatible with the positioning slot (722). One end of the arc-shaped tube (71) is provided with a docking groove (73), and the other end of the arc-shaped tube (71) is fixed with a docking ring (74) that is compatible with the docking groove (73). The two arc-shaped tubes (71) are centrally symmetrically distributed, and the docking ring (74) and the docking groove (73) are inserted into each other.

3. The mold for casting a cavity-type cast iron insert ring according to claim 2, characterized in that: The lower mold (2) has an upper retaining ring (82) at the upper opening and a lower retaining ring (83) at the bottom. The bottom of the lower mold (2) has a stepped hole (21) through it. The lower retaining ring (83) is located in the inner cavity of the opening end of the stepped hole (21) and is adapted to it. The upper mold (3) is annular and presses the upper retaining ring (82) from top to bottom. The upper retaining ring (82), the shaping ring (8), and the lower retaining ring (83) are concentric.

4. The mold for casting a cavity-type cast iron insert ring according to claim 3, characterized in that: The lower mold (2) has a cooling cylinder (4) in the middle of its inner cavity, and the lower end of the cooling cylinder (4) moves through the inner cavity of the stepped hole (21). The upper retaining ring (82), the shaping ring (8) and the lower retaining ring (83) are all movably sleeved on the outside of the cooling cylinder (4) and adapted to it. The upper end of the cooling cylinder (4) moves through the middle of the upper mold (3) and extends to the top of the upper mold (3).

5. A mold for casting a cavity-type cast iron insert ring according to claim 4, characterized in that: The upper mold (3) is provided with a lower pressure ring (31) on its upper side. The lower surface of the lower pressure ring (31) is fixedly connected with a plurality of lower pressure columns (32) arranged in a ring array. The lower pressure columns (32) move through the upper mold (3) and abut against the upper surface of the upper retaining ring (82). The lower pressure ring (31) and the upper mold (3) are locked together by fastening bolts (33). The side wall of the lower mold (2) and the side wall of the upper mold (3) are both fixed with connecting bosses (34), and two adjacent connecting bosses (34) are fixedly connected by bolts.

6. A mold for casting a cavity-type cast iron insert ring according to claim 5, characterized in that: The inner cavity of the cooling cylinder (4) is provided with an inner cylinder (42) concentric with it, and the upper ends of the two are fixedly connected. A flow guide baffle (43) is fixedly provided in the gap between the cooling cylinder (4) and the inner cylinder (42). The flow guide baffle (43) is spiral in shape. There are two sets of the flow guide baffle (43), and an upward flow channel (431) and a downward flow channel (432) are formed between the two sets of flow guide baffles (43). The upward flow channel (431) and the downward flow channel (432) are interconnected in the upper region between the cooling cylinder (4) and the inner cylinder (42). The lower end of the upward flow channel (431) and the lower end of the downward flow channel (432) are both connected to a circulation pipe (41). The two circulation pipes (41) are respectively connected to the inlet and outlet of the external cooling circulation pump.

7. A mold for casting a cavity-type cast iron insert ring according to claim 6, characterized in that: The lower mold (2) is placed on the upper surface of the support base (1). A limiting ring (44) is fixed on the outer side of the cooling cylinder (4). The lower end of the cooling cylinder (4) is inserted into the support base (1) and the limiting ring (44) fits against the upper surface of the support base (1). A rotating table (6) is rotatably installed on the lower end of the outer wall of the lower mold (2). A notch (11) located directly below the rotating table (6) is opened at the corner of the support base (1).

8. A mold for casting a cavity-type cast iron insert ring according to claim 7, characterized in that: The lower outer wall of the lower mold (2) is provided with a receiving groove (22) and the receiving groove (22) is semi-circular. The bottom of the receiving groove (22) is provided with a pouring inlet (23) that communicates with the inner cavity of the lower mold (2). Half of the rotating table (6) is located in the inner cavity of the receiving groove (22) and the other half is located outside the receiving groove (22). The interior of the rotating table (6) is provided with a "U"-shaped pouring connection channel (61). The outer side of the lower mold (2) is fixedly installed with a pouring pipe (5) by a bracket. The lower end face of the pouring pipe (5) is attached to the upper surface of the rotating table (6). The two ends of the pouring connection channel (61) are respectively connected to the lower end opening of the pouring pipe (5) and the pouring inlet (23).

9. A mold for casting a cavity-type cast iron insert ring according to claim 8, characterized in that: The lower opening of the storage trough (22) is provided with a bottom cover (24), and the bottom cover (24) is fixedly connected to the lower mold (2) by bolts. A circular boss (241) is fixedly provided on the upper surface of the bottom cover (24). The circular boss (241) is inserted into the middle of the rotating platform (6) and rotated therewith. The inner wall of the casting connection channel (61) is provided with a slag discharge hole (62) that extends downwards, and the center of the slag discharge hole (62) is misaligned with the center of the rotating platform (6). The surface of the circular boss (241) is provided with a slag discharge port (25) that extends downwards, and the center of the slag discharge port (25) is misaligned with the center of the circular boss (241). The surface of the rotating platform (6) is provided with a slag discharge hole (63). After the rotating platform (6) rotates 90 degrees, the slag discharge hole (62) and the slag discharge port (25) are connected accordingly, and the slag discharge hole (63) and the casting pipe (5) are connected accordingly.

10. A process for casting a hollow cast iron insert ring, characterized in that: Using the mold described in claim 9 specifically includes the following steps: Step 1: Pass the cooling cylinder (4) through the inner cavity of the lower mold (2), place the lower mold (2) on the upper surface of the support base (1), and insert the lower end of the cooling cylinder (4) into the support base (1). Stack multiple shaping rings (8) and multiple annular tubes (7) in the inner cavity of the lower mold (2) in sequence at intervals, and place the lower retaining ring (83) and the upper retaining ring (82) at the bottom and upper opening of the inner cavity of the lower mold (2) respectively. Cover the upper mold (3) at the upper opening of the lower mold (2) and lock the two together with bolts. Step 2: Adjust the fastening bolt (33) to press down the lower pressure ring (31) so that the lower end of the lower pressure column (32) presses down and tightens against the upper retaining ring (82); Step 3: Add molten metal to the inner cavity of the casting pipe (5). The molten metal passes through the casting connection channel (61) and the casting inlet (23) and is injected into the inner cavity of the lower mold (2) until the inner cavity of the lower mold (2) is filled. Step 4: Rotate the rotating table (6) 90 degrees so that the lower opening of the casting inlet (23) is blocked by the surface of the rotating table (6). The first slag discharge hole (62) is connected to the slag discharge port (25), and the second slag discharge hole (63) is connected to the casting pipe (5). At this time, the excess melt in the inner cavity of the casting pipe (5) and the inner cavity of the casting connection channel (61) is discharged from the second slag discharge hole (63) and the slag discharge port (25) respectively. Step 5: After the molten metal in the inner cavity of the lower mold (2) solidifies, a cast iron insert ring (9) is formed. The cast iron insert ring (9) together with multiple shaping rings (8) and multiple annular tubes (7) are taken out. Annular flanges (91) are cut and formed on the outside of the cast iron insert ring (9). Then, horizontal cuts are made between two adjacent annular tubes (7). Finally, the shaping rings (8) and the cast iron insert ring (9) are separated.

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