A device for preventing surface blowhole of coated sand shell mold hydraulic casting

Abstract

The application discloses a coated sand shell type hydraulic casting surface pore prevention device and relates to the technical field of castings. The device comprises the following steps: putting sand into a mold, the mold being provided with an exhaust device, the exhaust device discharging air in the mold when the mold is closed, and the mold comprising a fixed mold, a movable mold and an upper mold, the top surface of the fixed mold being provided with a mold cavity, a sliding sleeve being vertically arranged on the movable mold and freely sliding, the lower end of the sliding sleeve being coaxially fixedly connected with an elastic sleeve, a communication cavity being formed in the elastic sleeve, the outer diameter of the elastic sleeve gradually increasing from top to bottom, a taper hole being formed in the bottom surface of the fixed mold and being used for clamping the elastic sleeve, and the exhaust device comprising an exhaust mechanism and a driving mechanism, the driving mechanism being used for driving the sliding sleeve to move upwards until the lower end surface of the elastic sleeve is flush with the bottom surface of the upper mold. When the mold is closed, the exhaust device discharges air in the sand, so that the surface pore rate of the sand after casting is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of castings, in particular to a device for preventing surface pores of a coated sand shell type hydraulic casting. BACKGROUND

[0002] Coated sand, sand particles are covered with a layer of solid resin film before molding. There are two coating processes: cold method and hot method. The cold method dissolves the resin with ethanol and adds urotropine during sand mixing to coat the sand particles. The ethanol evaporates to obtain coated sand. The hot method preheats the sand to a certain temperature, adds resin to melt it, and stirs to coat the sand particles. Add urotropine solution and lubricant, cool, crush and sieve to get coated sand. Used for casting steel and iron parts.

[0003] When the coated sand shell casting is cast, the mold cavity of the mold is first filled with sand, and the sand is pressed into a fixed shape. However, since the sand particles may not be tightly packed with each other, air may be trapped in the sand, which may cause pores on the surface of the casting after the casting is completed, thereby affecting the surface quality of the casting.

[0004] For example, patent CN 114453557 A discloses a coated sand shell casting process, which includes the following steps: S1, making a shell mold with coated sand, the shell mold includes a first half mold and a second half mold that can form a mold cavity after being closed, and the shell mold has a vent hole that communicates between the inside and outside of the mold cavity; S2, closing the first half mold and the second half mold, then bonding and fixing the exhaust pipe at the vent hole with hot melt adhesive, and coating a high-temperature resistant adhesive on the surface of the hot melt adhesive; S3, fixing the shell mold after closing and coating in S2 to a sand box and pouring. The exhaust pipe formed by closing the mold is omitted, which can greatly reduce the amount of coated sand used, thereby saving costs; the mold cavity, exhaust pipe and sprue cup are connected through the exhaust pipe and vent hole, thereby realizing pouring.

[0005] However, since the inner cavity gas is generated when the first half mold and the second half mold are closed, it is difficult to completely exhaust through a single vent hole, thereby affecting product quality. Moreover, due to the particularity of the casting product, such as the manufacturing process of the oil inlet valve casting, the internal oil passage formed by the shell mold and the sand core is small, the sand core is easy to break, and it is also impossible to place a core bone. In addition, since the main flow passage of the product is small, it is impossible to set up a gas vent, so the surface of the casting is easy to form bubbles. Therefore, a coated sand shell type hydraulic casting surface pore prevention device with reasonable exhaust function and structure is needed. SUMMARY

[0006] The present application aims to provide a coated sand shell type hydraulic casting surface pore prevention device to solve the problems raised in the background art.

[0007] To achieve the above object, the present application provides the following technical solutions:

[0008] A device for preventing surface pores of coated sand shell type hydraulic casting, comprising:

[0009] The molding sand is put into the mold, the mold is provided with an exhaust device, the exhaust device exhausts the air in the mold when the mold is closed, and the mold comprises:

[0010] The fixed mold and the movable mold, the bottom of the movable mold is fixedly connected with an upper mold, and the top surface of the fixed mold is provided with a mold cavity matched with the upper mold:

[0011] A sliding sleeve is vertically arranged on the movable mold and freely slides, the lower end of the sliding sleeve is coaxially fixedly connected with an elastic sleeve, the inside of the elastic sleeve is provided with a communication cavity, the outer diameter of the elastic sleeve increases from top to bottom, the tapered edge of the elastic sleeve is provided with a fine slit penetrating through the communication cavity, and the bottom surface of the fixed mold is provided with a tapered hole for clamping the elastic sleeve;

[0012] The exhaust device comprises:

[0013] An exhaust mechanism arranged on the sliding sleeve;

[0014] A driving mechanism arranged on the movable mold, the driving mechanism is used for driving the sliding sleeve to move upwards until the lower end surface of the elastic sleeve is flush with the bottom surface of the upper mold.

[0015] Further, the upper surface of the fixed mold is fixedly connected with a guide column, and the movable mold is provided with a guide hole for the guide column to freely pass through.

[0016] Further, the exhaust mechanism comprises a fixed cylinder vertically fixed on the upper surface of the fixed mold, the inside of the fixed cylinder is hollow, and a piston is clamped in the fixed cylinder, the piston freely slides up and down in the fixed cylinder, the upper side of the outer wall of the fixed cylinder is provided with a first connecting port, the upper end surface of the sliding sleeve is provided with a second connecting port, the second connecting port is penetrated through the inside of the communication cavity, the first connecting port is connected with the second connecting port through an air pipe, and the sliding sleeve is provided with a lifting unit for driving the piston to move downwards.

[0017] Further, the lifting unit comprises a floating rod coaxially fixed on the piston, the upper end of the floating rod penetrates out of the fixed cylinder and freely slides up and down, the sliding sleeve is fixedly sleeved with a locking ring, the circumferential edge of the locking ring is fixedly connected with a pressing arm, and the pressing arm is matched with the upper end of the floating rod.

[0018] Further, a first tension spring is vertically installed in the fixed cylinder, the first tension spring is sleeved on the floating rod, and the two ends of the elastic force direction of the first tension spring are respectively elastically abutted against the piston and the top wall in the fixed cylinder.

[0019] Further, the driving mechanism comprises a second tension spring sleeved on the sliding sleeve, two ends of the second tension spring in the elastic force direction elastically abut against the locking ring and the movable mold respectively.

[0020] Further, two sides of the fixed mold are horizontally provided with rectangular rods, the rectangular rods are freely slid on the fixed mold, one end of the rectangular rod penetrates into the mold cavity, the movable mold is provided with a translation mechanism for driving the relative movement of the two rectangular rods.

[0021] Further, the translation mechanism comprises a connecting block fixed on one end of the rectangular rod penetrating out of the fixed mold, a nut sleeve is fixedly embedded on the connecting block, the fixed mold is horizontally rotatably connected with a rotating rod, two ends of the rotating rod are provided with threaded segments, the two threaded segments are threadedly provided on the two nut sleeves respectively, the screw rotation directions of the two threaded segments are opposite, and the movable mold is provided with a rotating unit for driving the rotation of the rotating rod.

[0022] Further, the rotating unit comprises a fixed plate fixed on the movable mold, a connecting arm is welded on the fixed plate, a rack is arranged on the connecting arm, and gears are sleeved on two ends of the rotating rod respectively, the gears are meshed with the rack.

[0023] Compared with the prior art, the beneficial effects of the present application are:

[0024] The present application can reduce the surface porosity of the finished product of the castings by the exhaust device to exhaust the air in the sand during the mold closing.

[0025] The present application can make the elastic sleeve slide in the taper hole when the sliding sleeve moves upward, until the lower end surface of the elastic sleeve is flush with the bottom surface of the upper mold, and the fine gap is in a closed state, so as to make the mold cavity inside be sealed, and avoid affecting the finished product quality of the castings.

[0026] The present application can make the two rectangular rods move towards the inside of the mold cavity until the end surface of the rectangular rod is flush with the inner wall of the mold cavity, so as to extrude the sand in the mold cavity, and make the air in the sand quickly exhaust into the fine gap of the elastic sleeve. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 It is a structure schematic view of the device for preventing surface porosity of the coated sand shell mold hydraulic casting in the present application;

[0028] Figure 2 It is Figure 1 It is an enlarged schematic view of the local structure at A in the present application;

[0029] Figure 3 It is Figure 1The sectional view of the middle structure is shown schematically;

[0030] Figure 4 For Figure 3 The enlarged schematic view of the local structure at B is shown;

[0031] Figure 5 For Figure 1 The front view angle schematic view of the structure is shown;

[0032] Figure 6 The structure schematic view of the sliding sleeve and the elastic sleeve after assembly is shown in the application;

[0033] Figure 7 For Figure 6 The sectional view of the structure is shown schematically.

[0034] In the figure, the reference signs are explained as follows: 1, fixed mold; 2, fixed cylinder; 3, pressure arm; 4, movable mold; 5, guide column; 6, fixed plate; 7, connecting arm; 8, gear; 9, rotating rod; 10, threaded section; 11, rectangular rod; 12, first connecting port; 13, floating rod; 14, second connecting port; 15, second tension spring; 16, sliding sleeve; 17, connecting block; 18, nut sleeve; 19, thin gap; 20, elastic sleeve; 21, communicating cavity; 22, upper mold; 23, piston; 24, first tension spring. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the application.

[0036] Please refer to Figures 1-7 The application provides a technical solution: a device for preventing surface pores of coated sand shell type hydraulic casting. The device is based on a mold with an exhaust function. The mold comprises a movable mold 4 and a fixed mold 1. The fixed mold 1 is installed on a casting device, and the movable mold 4 is located above the fixed mold 1. In addition, a hydraulic device is arranged on the casting device, and the hydraulic device is used to drive the movable mold 4 to move up and down. The bottom of the movable mold 4 is fixedly connected with an upper mold 22. The top surface of the fixed mold 1 is provided with a mold cavity used in cooperation with the upper mold 22. When casting, the mold sand is poured into the mold cavity, and then the movable mold 4 is driven to move downward by the hydraulic device, so that the upper mold 22 is clamped into the mold cavity, and then the mold sand is extruded and formed. The upper surface of the fixed mold 1 is fixedly connected with a guide column 5, and the movable mold 4 is provided with a guide hole through which the guide column 5 can freely pass. The guide column 5 slides in the guide hole, thereby guiding the upward and downward movement of the movable mold 4.

[0037] The upper end surface of the movable die 4 is vertically provided with a sliding sleeve 16 which vertically freely slides on the movable die 4. The lower end of the sliding sleeve 16 is coaxially fixedly connected with an elastic sleeve 20. The elastic sleeve 20 is internally provided with a communicating cavity 21. The outer diameter of the elastic sleeve 20 is gradually increased from top to bottom. The tapered edge of the elastic sleeve 20 is provided with a thin slit 19 which penetrates the communicating cavity 21. The bottom surface of the fixed die 1 is provided with a tapered hole for clamping the elastic sleeve 20. The upper surface of the fixed die 1 is connected with a fixed cylinder 2. The fixed cylinder 2 is internally hollow and clamps a piston 23. The piston 23 freely slides in the fixed cylinder 2. The upper side outer wall of the fixed cylinder 2 is provided with a first connecting port 12. The upper end surface of the sliding sleeve 16 is provided with a second connecting port 14. The second connecting port 14 is internally penetrated with the communicating cavity 21. The first connecting port 12 is connected with the second connecting port 14 through an air pipe. The piston 23 is coaxially fixedly connected with a floating rod 13. The upper end of the floating rod 13 penetrates the fixed cylinder 2 and freely slides. The sliding sleeve 16 is fixedly sleeved with a locking ring. The peripheral edge of the locking ring is fixedly connected with a pressing arm 3 which cooperates with the upper end of the floating rod 13. The fixed cylinder 2 is vertically installed with a first tension spring 24 which is sleeved on the floating rod 13. The two ends of the first tension spring 24 in the elastic force direction are respectively elastically abutted against the piston 23 and the inner top wall of the fixed cylinder 2. The sliding sleeve 16 is sleeved with a second tension spring 15. The two ends of the second tension spring 15 in the elastic force direction are respectively elastically abutted against the locking ring and the movable die 4.

[0038] Before the mold is closed, the sliding sleeve 16 is moved downwardly by the pulling force of the second tension spring 15 on the locking ring. Thus the elastic sleeve 20 is moved downwardly and the lower end surface of the elastic sleeve 20 slightly protrudes to the bottom surface of the upper die 22. At this time, the thin slit 19 is not closed. Thus when the mold is closed, the pressing arm 3 gradually approaches the floating rod 13 until the pressing arm 3 presses the upper end of the floating rod 13. Thus the floating rod 13 drives the piston 23 to move downwardly. When moving downwardly, the piston 23 can increase the upper space in the fixed cylinder 2 so that the air pressure in the fixed cylinder 2 is decreased. At the same time, the upper die 22 extrudes the sand in the mold cavity. The air in the sand can be discharged into the communicating cavity 21 of the sliding sleeve 16 through the thin slit 19. Under the influence of the low air pressure in the fixed cylinder 2, the air in the sand is discharged into the fixed cylinder 2 from the communicating cavity 21.

[0039] The rectangular rod 11 is horizontally penetrated on both sides of the fixed mold 1, the rectangular rod 11 is freely slid on the fixed mold 1, one end of the rectangular rod 11 is penetrated into the mold cavity, the end of the rectangular rod 11 penetrating out of the fixed mold 1 is fixedly connected with the connecting block 17, the inner wall of the mold cavity is provided with a rectangular groove for the free passing of the rectangular rod 11, the connecting block 17 is fixedly embedded with the nut sleeve 18, the fixed mold 1 is horizontally rotatably connected with the rotating rod 9, the rotating rod 9 is provided with the threaded section 10 at both ends, the two threaded sections 10 are threadedly penetrated on the two nut sleeves 18 respectively, the screw rotation directions of the two threaded sections 10 are opposite, the movable mold 4 is fixedly connected with the fixed plate 6, the fixed plate 6 is welded with the connecting arm 7, the connecting arm 7 is provided with a rack, the rotating rod 9 is sleeved with the gear 8 at both ends, the gear 8 is engaged with the rack;

[0040] When the movable mold 4 moves downward, the fixed plate 6 moves downward, so that the rack on the connecting arm 7 is engaged with the gear 8, thereby driving the gear 8 to rotate, when the gear 8 rotates, the rotating rod 9 is driven to rotate, when the rotating rod 9 rotates, the two nut sleeves 18 are respectively threadedly screwed with the two nut sleeves 18, thereby driving the two connecting blocks 17 to relatively approach, so that the two rectangular rods 11 move towards the inside of the mold cavity, until the end surface of the rectangular rod 11 is flush with the inner wall of the mold cavity, thereby enabling the rectangular rod 11 to extrude the sand in the rectangular groove, so that the sand can be extruded and pressed.

[0041] The working principle of the present application is that the sand is put into the mold cavity, then the movable mold 4 is driven to move downward by the hydraulic device, so that the upper mold 22 is clamped into the mold cavity, thereby extruding and forming the sand, before the mold is closed, the second tension spring 15 pulls the locking ring, so that the sliding sleeve 16 moves downward, thereby enabling the elastic sleeve 20 to move downward, and the lower end surface of the elastic sleeve 20 slightly protrudes to the bottom surface of the upper mold 22, and at this time, the fine gap 19 is not closed, so that when the mold is closed, the pressure arm 3 gradually approaches the floating rod 13, until the pressure arm 3 presses the upper end of the floating rod 13, so that the floating rod 13 drives the piston 23 to move downward, when moving downward, the piston 23 can increase the upper space in the fixed cylinder 2, so that the air pressure in the fixed cylinder 2 decreases, at the same time, the upper mold 22 extrudes the sand in the mold cavity, and the air in the sand can be discharged into the communication cavity 21 of the sliding sleeve 16 through the fine gap 19, and under the influence of the low air pressure in the fixed cylinder 2, the air in the sand is discharged into the fixed cylinder 2 from the communication cavity 21;

[0042] When the movable die 4 moves downward, the fixed plate 6 will move downward, so that the rack on the connecting arm 7 engages with the gear 8, thereby driving the gear 8 to rotate, when the gear 8 rotates, the rotating rod 9 will be driven to rotate, when the rotating rod 9 rotates, the two nut sleeves 18 will be driven to threadedly engage with the two nut sleeves 18 respectively, thereby driving the two connecting blocks 17 to relatively close, so that the two rectangular rods 11 move towards the inside of the mold cavity, until the end face of the rectangular rod 11 is flush with the inner wall of the mold cavity, thereby enabling the rectangular rod 11 to extrude the molding sand in the rectangular groove, so that the molding sand can extrude each other, thereby enabling the air in the molding sand to be quickly extruded out.

[0043] It should be noted that the relational terms herein such as first and second and the like are used solely to distinguish one entity or action from another, without necessarily requiring or implying any such actual relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. Although embodiments of the present application have been shown and described, it is to be understood that various modifications, substitutions, alternatives, and variations can be made thereto without departing from the principles and spirit of the present application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A device for preventing surface porosity in coated sand-shell type hydraulic castings, characterized in that, include: Molding sand is poured into a mold, which is equipped with an venting device. When the mold is closed, the venting device expels the air from inside the mold. The mold includes: A fixed mold (1) and a moving mold (4), wherein the bottom of the moving mold (4) is fixedly connected to an upper mold (22), and the top surface of the fixed mold (1) is provided with a mold cavity that cooperates with the upper mold (22): A sliding sleeve (16) is vertically inserted into the moving mold (4) and slides freely. An elastic sleeve (20) is coaxially fixed to the lower end of the sliding sleeve (16). A communicating cavity (21) is opened inside the elastic sleeve (20). The outer diameter of the elastic sleeve (20) increases from top to bottom. A slit (19) is opened on the tapered edge of the elastic sleeve (20) to penetrate the communicating cavity (21). A tapered hole is opened on the bottom surface of the fixed mold (1) for the elastic sleeve (20) to be engaged. The exhaust device includes: An exhaust mechanism is provided on the sliding sleeve (16); A driving mechanism is provided on the moving mold (4), which is used to drive the sliding sleeve (16) to move upward until the lower end face of the elastic sleeve (20) is flush with the bottom surface of the upper mold (22); The exhaust mechanism includes a fixed cylinder (2) vertically fixed to the upper surface of the fixed mold (1). The fixed cylinder (2) is hollow inside and has a piston (23) engaged. The piston (23) slides freely up and down inside the fixed cylinder (2). The upper outer wall of the fixed cylinder (2) is provided with a first connection port (12). The upper end face of the sliding sleeve (16) is provided with a second connection port (14). The second connection port (14) is connected to the interior of the communicating cavity (21). The first connection port (12) is connected to the second connection port (14) through an air pipe. The sliding sleeve (16) is provided with a lifting unit for driving the piston (23) to move downward. A rectangular rod (11) is horizontally inserted on each side of the fixed mold (1). The rectangular rod (11) slides freely horizontally on the fixed mold (1). One end of the rectangular rod (11) is inserted into the mold cavity. The moving mold (4) is provided with a translation mechanism for driving the two rectangular rods (11) to move relative to each other. The translation mechanism includes a connecting block (17) fixedly connected to one end of the rectangular rod (11) extending out of the fixed mold (1). A nut (18) is fixedly embedded on the connecting block (17). A rotating rod (9) is horizontally rotatably connected to the fixed mold (1). Threaded sections (10) are provided at both ends of the rotating rod (9). The two threaded sections (10) are threaded onto the two nut (18) respectively. The threads of the two threaded sections (10) have opposite directions. A rotating unit for driving the rotating rod (9) to rotate is provided on the moving mold (4).

2. The device for preventing surface porosity in coated sand-shell type hydraulic castings according to claim 1, characterized in that, The fixed mold (1) has a guide post (5) fixedly attached to its upper surface, and the moving mold (4) has a guide hole for the guide post (5) to pass through freely.

3. The device for preventing surface porosity in coated sand-shell type hydraulic castings according to claim 1, characterized in that, The lifting unit includes a floating rod (13) coaxially fixed to the piston (23). The upper end of the floating rod (13) passes through the fixed cylinder (2) and slides freely up and down. A locking ring is fixedly sleeved on the sliding sleeve (16). A pressure arm (3) is fixedly connected to the periphery of the locking ring. The pressure arm (3) is used in conjunction with the upper end of the floating rod (13).

4. The device for preventing surface porosity in coated sand-shell type hydraulic castings according to claim 3, characterized in that, A first tension spring (24) is vertically installed inside the fixed cylinder (2). The first tension spring (24) is wrapped around the floating rod (13), and the two ends of the first tension spring (24) elastically abut against the piston (23) and the inner top wall of the fixed cylinder (2) respectively.

5. The device for preventing surface porosity in coated sand-shell type hydraulic castings according to claim 4, characterized in that, The driving mechanism includes a second tension spring (15) wrapped around the sliding sleeve (16), and the two ends of the second tension spring (15) elastically abut against the locking ring and the moving mold (4) respectively in the direction of the elastic force.

6. The device for preventing surface porosity in coated sand-shell type hydraulic castings according to claim 5, characterized in that, The rotating unit includes a fixed plate (6) fixed to the moving mold (4), a connecting arm (7) welded on the fixed plate (6), a rack on the connecting arm (7), and gears (8) fitted at both ends of the rotating rod (9), the gears (8) meshing with the rack.

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