A positive and negative pressure sand injection mechanism for a core making machine

Abstract

The present invention discloses a positive and negative pressure sand shooting mechanism for a core making machine, which includes a frame. On the left and right sides of the frame, a left mold and a right mold are respectively installed. The second mold clamping servo cylinders are fixed on the front and rear sides of the top of the frame. A pressing box cylinder is fixed on the top of the frame. Moving servo cylinders are horizontally fixed at the left and right sides of the top of the frame. The heat curing box and the sand shooting box are respectively arranged on both sides of the top of the frame. The positive and negative pressure adjusting plate is embedded in the sand shooting box. An adjusting cavity is formed on the bottom surface of the positive and negative pressure adjusting plate. The pressure air pipe is installed through the positive and negative pressure adjusting plate. A sand hopper is installed on the top of the sand shooting box. This positive and negative pressure sand shooting mechanism for the core making machine, through the switching of positive and negative pressures, on the one hand improves the sand shooting efficiency, on the other hand avoids the leakage of excess sand and gravel, and at the same time can automatically adjust the opening and closing of the sand shooting holes according to the specifications of the mold, is applicable to the production of different molds, and has a high degree of automation.

Description

Technical Field

[0001] The present invention relates to the technical field of core-making machines, and particularly to a positive and negative pressure sand shooting mechanism for a core-making machine. Background Technique

[0002] A core-making machine shoots a sand core into a core box at a high speed. Under certain temperature conditions of the mold, through high-temperature gas, the sand core in the core box is quickly formed to obtain a finished product. It mainly includes a sand shooting mechanism, a mold closing mechanism, a thermal curing box, a core pulling and demolding mechanism, etc. The core made by the core-making machine has precise dimensions and a smooth surface, and is widely used in the casting machinery industry. Among them, the sand shooting mechanism is particularly important, which is related to the forming quality of the finished product. However, the existing sand shooting mechanisms have the following problems when in use:

[0003] Most of the existing sand shooting mechanisms use high-speed air flow to shoot the sand core into the core box, so that the sand core quickly fills the core box. However, when the existing sand shooting mechanism is in use, it is not convenient to use positive and negative pressure for auxiliary forming. On the one hand, when shooting alone with high-speed air flow, the air pressure is relatively large, and it is easy to cause wear on the mold after long-term use. At the same time, there is still a situation where the sand shooting efficiency is not high. On the other hand, the excess sand core stays in the sand shooting mechanism. Under the action of gravity, the sand core is easy to fall on the sand shooting plate and the mold, resulting in the need for cleaning every time a core is made, which is very troublesome. At the same time, when performing core-making operations, different molds are usually replaced for casting different workpieces. The existing sand shooting mechanism is not convenient to automatically open and close and adjust the corresponding positions of the sand shooting holes. When replacing the mold, it is also necessary to replace the corresponding sand shooting mechanism, which is troublesome to operate, increases the use cost and replacement time, and affects the processing efficiency.

[0004] In view of the above problems, there is an urgent need to innovate and design on the basis of the original sand shooting mechanism. Summary of the Invention

[0005] The purpose of the present invention is to provide a positive and negative pressure sand shooting mechanism for a core-making machine to solve the problems in the above background technique that the existing sand shooting mechanism is not convenient to use positive and negative pressure for auxiliary forming and is not convenient to automatically open and close and adjust the corresponding positions of the sand shooting holes. The technical solution of the present invention provides a solution significantly different from the prior art for the technical problem that the prior art solution is too single.

[0006] To achieve the above purpose, the present invention provides the following technical solution: A positive and negative pressure sand shooting mechanism for a core-making machine includes a frame. Left and right molds are respectively installed on the left and right sides of the frame. A mold ejection base is provided at the bottom of the frame, and a bottom mold is installed on the top of the mold ejection base. First mold closing servo cylinders are fixed between the bottom mold and the mold ejection base, and between the left and right molds and the frame. At the same time, a core pulling mechanism is movably installed at the top edge of the mold ejection base;

[0007] It further includes:

[0008] The second die - closing servo cylinder is fixed to the front and rear sides of the top of the frame. The output end of the second die - closing servo cylinder is connected to the upper die - closing template, and the upper die - closing template is located inside the frame. A pressing box cylinder is fixed to the top of the frame and is located between the two second die - closing servo cylinders. A sand - shooting air pipe penetrates through the pressing box cylinder. Horizontally fixed to the left and right sides of the top of the frame are moving servo cylinders. The output end of the moving servo cylinder is connected to a mounting frame, and the mounting frame is movably installed on a guide rail. The guide rail is horizontally fixed to the frame. At the bottom positions of the left and right groups of mounting frames, a heat - curing box and a sand - shooting box are respectively fixed. The heat - curing box and the sand - shooting box are respectively arranged on both sides of the top of the frame. A return spring is fixed between the heat - curing box and the sand - shooting box and the mounting frame. And a sand - shooting hole is opened at the bottom of the sand - shooting box;

[0009] The positive - negative pressure regulating plate is embedded in the sand - shooting box. Horizontally penetrating through the positive - negative pressure regulating plate is a positive - negative pressure pipe. At the bottom of the positive - negative pressure pipe and the corresponding position at the bottom of the positive - negative pressure regulating plate, air holes are both opened through. And a filter screen is fixed in the air hole at the bottom of the positive - negative pressure regulating plate. One end of the positive - negative pressure pipe is located outside the sand - shooting box. An adjusting cavity is opened on the bottom surface of the positive - negative pressure regulating plate. The adjusting cavity is located on one side of the positive - negative pressure pipe. A blocking block is connected in the adjusting cavity through an adjusting spring. And a pressure air pipe is fixedly penetrated through one side of the adjusting cavity. The pressure air pipe penetrates through the positive - negative pressure regulating plate, and one end of the pressure air pipe is located outside the sand - shooting box. A sand hopper is installed on the top of the sand - shooting box. The sand hopper is fixed at the edge of the top of the frame, and a butterfly valve is installed at the bottom of the sand hopper.

[0010] Preferably, a bottom plate adapted to the tops of the heat - curing box and the sand - shooting box is arranged at the bottom of the pressing box cylinder. Through holes are opened at the tops of the heat - curing box and the sand - shooting box. The internal cavity of the heat - curing box is filled with ceramic heat - storage particles, and an electric heating wire is installed in the heat - curing box. After the pressing box cylinder presses the heat - curing box and the sand - shooting box onto the upper die - closing template, the upper die - closing template can be adaptively installed with the heat - curing box or the sand - shooting box and the bottom of the pressing box cylinder, which is convenient for the sand - shooting air pipe on the pressing box cylinder to ventilate for sand - shooting and air - conveying heating operations. The ceramic heat - storage particles in the heat - curing box cooperate with the electric heating wire to conduct pre - heat storage, improving the heat - curing effect.

[0011] Preferably, the cross - section of the mounting frame is in an "L" - shaped structure. The mounting frame elastically slides with the heat - curing box and the sand - shooting box through the return spring. And a hole corresponding to the sand - shooting hole is opened at the bottom of the heat - curing box. When the pressing box cylinder presses the heat - curing box and the sand - shooting box, the mounting frame can keep the heat - curing box and the sand - shooting box stable under pressure. At the same time, the heat - curing box and the sand - shooting box can return to their original positions after being pressed.

[0012] Preferably, the air holes are equally angularly distributed at the bottom of the positive and negative pressure pipes and the positive and negative pressure regulating plate, and are staggered with the sand shooting holes. By introducing air into the positive and negative pressure pipes, positive pressure sand blasting can be carried out on the sand shooting holes. At the same time, air is drawn out of the positive and negative pressure pipes to form a negative pressure, avoiding the fall of excess sand and gravel in the sand shooting box.

[0013] Preferably, the filter screen adopts a four-layer mesh structure, and the outer layer aperture of the filter screen is larger than the inner layer aperture. The sand and gravel are filtered through the filter screen to prevent the sand and gravel from entering the positive and negative pressure pipes. At the same time, the four-layer structure and the design of the large outer aperture of the filter screen ensure the stable use of the filter screen.

[0014] Preferably, the plug block is vertically elastically slid in the adjustment cavity by means of an adjustment spring, and the top cross-section of the plug block is in a "T" shape and fits and slides in the adjustment cavity. The pressure air pipe in the adjustment cavity is located above the plug block. The distribution position of the plug block corresponds to the distribution position of the sand shooting holes, and the bottom of the plug block is in concave-convex fit with the sand shooting holes. When the plug block is forced to insert into the sand shooting holes, the sand shooting holes can be blocked, which is suitable for the sand shooting core making operation of different molds. When changing different molds, there is no need to replace the sand shooting box.

[0015] Preferably, the number of the pressure air pipes is the same as the number of the plug blocks, and the pressure air pipes are arranged at both ends of the positive and negative pressure regulating plate. Whether to open or close which sand shooting hole according to the mold requirements is automatically controlled by the PLC to adjust the internal air pressure of the adjustment cavity. One end of each positive and negative pressure pipe is equipped with an electromagnetic replacement valve and is connected to a vacuum negative pressure gas storage tank and a positive pressure gas storage tank. The electromagnetic replacement valve on the positive and negative pressure pipes and the connection with the vacuum negative pressure gas storage tank and the positive pressure gas storage tank are controlled by the PLC to replace the positive and negative pressures. By controlling the entry and suction of each pressure air pipe through the PLC, the position of the corresponding plug block can be adjusted, and the degree of automation is high.

[0016] Preferably, the sand shooting box can be applied to other conventional core making machines.

[0017] Compared with the prior art, the beneficial effects of the present invention are:

[0018] 1. The present invention provides a positive and negative pressure assisted molding mechanism. A positive and negative pressure pipe is arranged in the sand shooting box. By connecting an external vacuum pump, air intake and suction vacuum in the positive and negative pressure pipe are realized. During the sand shooting process, high-speed air flow enters the sand shooting box through the sand shooting air pipe for sand shooting operation. At this time, the positive and negative pressure pipe provides positive pressure, which is blown into the sand shooting hole through the air hole to cooperate with the sand shooting air pipe for sand shooting operation, improving the sand shooting efficiency and reducing the occurrence of insufficient sand shooting. Through sand shooting with two air flows, the air transmission pressure in a single pipe is reduced, the power consumption of the pressure supply equipment is reduced. At the same time, the overall pressure is reduced, which also reduces the wear of the mold and improves the service life. In the traditional technology, mostly single sand shooting is used, and a relatively large pressure needs to be provided in the sand shooting pipe, which will cause certain losses to the sand shooting pipe and the mold. At the same time, with single sand shooting, the sand shooting speed is relatively low, resulting in an increase in processing time and affecting the processing efficiency. After the sand shooting is completed, a negative pressure is formed in the positive and negative pressure pipe, which can adsorb the redundant sand cores in the sand shooting box, preventing the redundant sand from falling from the sand shooting hole and avoiding the trouble of subsequent manual cleaning. In the traditional technology, the falling of the sand cores will also cause blockage of the sand shooting plate, which needs to be disassembled and cleaned, causing great trouble. By using the switching of positive and negative pressure, while improving the sand shooting efficiency, the subsequent maintenance time is reduced, further improving the work efficiency. At the same time, the number of molded parts is greatly increased within the same time, thus improving the economic benefits;

[0019] 2. The present invention provides a sand shooting hole automatic switching mechanism. By installing multiple pressure air pipes in the positive and negative pressure regulating plate in the sand shooting box, when air enters the pressure air pipes, the plug block is pressed downward, blocking the corresponding sand shooting hole. At the same time, under the action of the regulating spring, when no air enters the pressure air pipes, the plug block resets to open the sand shooting hole at the corresponding position, realizing the switching of the sand shooting hole. When performing molding operations on molds with different structures, only different molds need to be replaced, and there is no need to replace the sand shooting box. Only after the PLC controller edits the program and inputs the corresponding values, the automatic switching of the sand shooting hole can be realized, with a high degree of automation, greatly reducing the use of workpieces, saving production costs, and at the same time reducing the mold replacement time, further improving the work efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic diagram of the three-dimensional structure of the present invention from the first perspective;

[0021] Figure 2 is a schematic diagram of the three-dimensional structure of the present invention from the second perspective;

[0022] Figure 3 is a schematic diagram of the front structure of the present invention;

[0023] Figure 4 is a schematic diagram of the three-dimensional structure of the bottom of the thermal curing box of the present invention;

[0024] Figure 5Schematic diagram of the three-dimensional structure of the bottom of the sand shooting box of the present invention;

[0025] Figure 6 Schematic diagram of the three-dimensional structure of the third perspective of the present invention;

[0026] Figure 7 Schematic diagram of the three-dimensional structure inside the sand shooting box of the present invention;

[0027] Figure 8 Schematic diagram of the front sectional structure of the positive and negative pressure pipes of the present invention;

[0028] Figure 9 Schematic diagram of the front sectional structure of the plug block of the present invention;

[0029] Figure 10 Schematic diagram of the distribution structure of the air holes on the positive and negative pressure pipes of the present invention.

[0030] In the figure: 1, frame; 2, left mold; 3, right mold; 4, mold ejection seat; 5, bottom mold; 6, first mold clamping servo cylinder; 7, core pulling mechanism; 8, second mold clamping servo cylinder; 9, upper mold clamping plate; 10, pressing box cylinder; 11, sand shooting air pipe; 12, moving servo cylinder; 13, mounting frame; 14, guide rail; 15, thermal curing box; 16, sand shooting box; 17, return spring; 18, sand shooting hole; 19, positive and negative pressure regulating plate; 20, positive and negative pressure pipe; 21, air hole; 22, filter screen; 23, regulating cavity; 24, regulating spring; 25, plug block; 26, pressure air pipe; 27, sand hopper; 28, butterfly valve. Detailed implementation manners

[0031] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0032] Please refer to Figures 1-10 , the present invention provides a technical solution: a positive and negative pressure sand shooting mechanism for a core making machine, including a frame 1, a left mold 2, a right mold 3, a mold ejection seat 4, a bottom mold 5, a first mold clamping servo cylinder 6, a core pulling mechanism 7, a second mold clamping servo cylinder 8, an upper mold clamping plate 9, a pressing box cylinder 10, a sand shooting air pipe 11, a moving servo cylinder 12, a mounting frame 13, a guide rail 14, a thermal curing box 15, a sand shooting box 16, a return spring 17, a sand shooting hole 18, a positive and negative pressure regulating plate 19, a positive and negative pressure pipe 20, an air hole 21, a filter screen 22, a regulating cavity 23, a regulating spring 24, a plug block 25, a pressure air pipe 26, a sand hopper 27 and a butterfly valve 28;

[0033] Embodiment 1

[0034] Please refer to Figures 1-6 , including a frame 1, a left mold 2 and a right mold 3 are respectively installed on the left and right sides of the frame 1, and a mold ejection base 4 is arranged at the bottom of the frame 1, and a bottom mold 5 is installed on the top of the mold ejection base 4. Moreover, a first mold clamping servo cylinder 6 is fixed between the bottom mold 5 and the mold ejection base 4, and between the left mold 2, the right mold 3 and the frame 1. At the same time, a core-pulling mechanism 7 is movably installed at the top edge of the mold ejection base 4; the second mold clamping servo cylinder 8 is fixed on the front and rear sides of the top of the frame 1, and the output end of the second mold clamping servo cylinder 8 is connected with an upper mold clamping plate 9, and the upper mold clamping plate 9 is located inside the frame 1. A pressing box cylinder 10 is fixed on the top of the frame 1, and the pressing box cylinder 10 is located between the two second mold clamping servo cylinders 8, and a sand injection air pipe 11 is installed through the pressing box cylinder 10. The left and right sides of the top of the frame 1 are horizontally fixed with a moving servo cylinder 12, and the output end of the moving servo cylinder 12 is connected with a mounting bracket 13, and the mounting bracket 13 is movably installed on a guide rail 14, and the guide rail 14 is horizontally fixed on the frame 1. At the same time, a heat curing box 15 and a sand injection box 16 are respectively fixed at the bottom positions of the left and right groups of mounting brackets 13. The heat curing box 15 and the sand injection box 16 are respectively arranged on both sides of the top of the frame 1, and a return spring 17 is fixed between the heat curing box 15, the sand injection box 16 and the mounting bracket 13. Moreover, a sand injection hole 18 is opened at the bottom of the sand injection box 16; a bottom plate adapted to the tops of the heat curing box 15 and the sand injection box 16 is arranged at the bottom of the pressing box cylinder 10, and inlet holes are opened at the tops of the heat curing box 15 and the sand injection box 16. Moreover, the inner cavity of the heat curing box 15 is filled with ceramic heat storage particles, and an electric heating wire is installed in the heat curing box 15. The cross section of the mounting bracket 13 is in an "L" shape, and the mounting bracket 13 elastically slides with the heat curing box 15 and the sand injection box 16 through the return spring 17. Moreover, a hole corresponding to the sand injection hole 18 is opened at the bottom of the heat curing box 15; through the cooperation of the first mold clamping servo cylinder 6, the second mold clamping servo cylinder 8 and the moving servo cylinder 12, the sand injection positioning accuracy is improved, the box inlet speed is increased, the stability is improved, and at the same time, the speed and smoothness of mold clamping and mold opening are improved, and the noise is reduced;

[0035] Embodiment 2

[0036] Please refer to Figures 1-3 and Figures 7-8, the positive and negative pressure regulating plate 19 is embedded in the sand shooting box 16. A positive and negative pressure pipe 20 is horizontally installed through the positive and negative pressure regulating plate 19. Air holes 21 are opened at corresponding positions at the bottom of the positive and negative pressure pipe 20 and the bottom of the positive and negative pressure regulating plate 19. A filter screen 22 is fixed in the air hole 21 at the bottom of the positive and negative pressure regulating plate 19. One end of the positive and negative pressure pipe 20 is located outside the sand shooting box 16. The air holes 21 are distributed at equal angles at the bottom of the positive and negative pressure pipe 20 and the positive and negative pressure regulating plate 19, and are staggered with the sand shooting holes 18. The filter screen 22 adopts a four-layer mesh structure, and the outer pore diameter of the filter screen 22 is larger than the inner pore diameter. By switching the positive and negative pressure of the positive and negative pressure pipe 20, the sand shooting efficiency is improved, the phenomenon of insufficient sand shooting is reduced, and at the same time, the leakage of excess sand cores is avoided;

[0037] Embodiment 3

[0038] Please refer to Figures 1-3 、 Figure 7 and Figures 9-10 , an adjustment cavity 23 is opened on the bottom surface of the positive and negative pressure regulating plate 19. The adjustment cavity 23 is located on one side of the positive and negative pressure pipe 20. A plug 25 is connected in the adjustment cavity 23 through an adjustment spring 24. One side of the adjustment cavity 23 is fixedly connected with a pressure air pipe 26. The pressure air pipe 26 is installed through the positive and negative pressure regulating plate 19, and one end of the pressure air pipe 26 is located outside the sand shooting box 16. A sand hopper 27 is installed on the top of the sand shooting box 16, and the sand hopper 27 is fixed at the top edge of the frame 1. A butterfly valve 28 is installed at the bottom of the sand hopper 27. The plug 25 is vertically elastically slid in the adjustment cavity 23 through the adjustment spring 24, and the top cross-section of the plug 25 is in a "T" shape and fits and slides in the adjustment cavity 23. The pressure air pipe 26 in the adjustment cavity 23 is located above the plug 25. The distribution position of the plug 25 corresponds to the distribution position of the sand shooting holes 18, and the bottom of the plug 25 is in concave-convex fit with the sand shooting holes 18. The number of the pressure air pipes 26 is the same as the number of the plugs 25, and the pressure air pipes 26 are arranged and distributed at both ends of the positive and negative pressure regulating plate 19. Whether to open or close which sand shooting hole 18 of the pressure air pipe 26 is automatically controlled by the PLC to adjust the internal air pressure of the adjustment cavity 23. One end of each positive and negative pressure pipe 20 is installed with an electromagnetic replacement valve and is connected with a vacuum negative pressure gas storage tank and a positive pressure gas storage tank. The electromagnetic replacement valve on the positive and negative pressure pipe 20 and the connection of the vacuum negative pressure gas storage tank and the positive pressure gas storage tank are controlled by the PLC to replace the positive and negative pressure; By controlling the intake and exhaust of the individual pressure air pipes 26, the position of the corresponding plug 25 is adjusted, and the sand shooting holes 18 are automatically switched, so as to be suitable for the use of different molds.

[0039] Working principle: When using the positive and negative pressure sand shooting mechanism for the core making machine, such as Figures 1-10In this process, first, the bottom mold 5 is pushed into the corresponding position through the mold ejection seat 4. Then, the first mold clamping servo cylinder 6 on the frame 1 is started, so that the left mold 2, the right mold 3 and the bottom mold 5 are clamped. Then, the core pulling mechanism 7 is pushed into the core, and the butterfly valve 28 on the sand hopper 27 is opened, so that the sand core enters the sand shooting box 16. There are matching holes at the top of the sand shooting box 16. At the same time, the second mold clamping servo cylinder 8 is started to drive the upper mold clamping plate 9 to move downward and cooperate with the left mold 2, the right mold 3 and the bottom mold 5. Then, the moving servo cylinder 12 is started to drive the mounting frame 13 to move on the guide rail 14, driving the sand shooting box 16 to reach above the upper mold clamping plate 9. Then, the pressing box cylinder 10 is started, and the sand shooting box 16 is pressed down to the top of the upper mold clamping plate 9 through the pressing box cylinder 10 to cooperate with the holes thereon for subsequent sand shooting operations. The high-speed air flow is shot into the sand shooting box 16 through the sand shooting air pipe 11 by an externally connected high-speed compressed air pump, so that the sand core in the sand shooting box 16 enters the mold through the sand shooting holes 18 and the holes in the upper mold clamping plate 9. At the same time, gas is introduced into the positive and negative pressure pipe 20 by an externally connected vacuum pump to provide positive pressure, so that the gas reaches the sand shooting holes 18 through the air holes 21 to provide additional sand shooting pressure and improve the sand shooting efficiency. After the sand shooting is completed, the vacuum pump at one end of the positive and negative pressure pipe 20 is started again to extract the gas, so that negative pressure is generated in the positive and negative pressure pipe 20 to adsorb the sand core in the sand shooting box 16 to prevent it from falling. At this time, the sand core is blocked by the filter screen 22. Then, the moving servo cylinder 12 is started to drive the sand shooting box 16 to perform the box returning operation. Another moving servo cylinder 12 is started to drive the thermal curing box 15 to reach the top of the upper mold clamping plate 9. And again through the pressing box cylinder 10, the thermal curing box 15 is pressed onto the upper mold clamping plate 9, and air is introduced through the sand shooting air pipe 11. The gas is heated through the thermal curing box 15 and enters the mold cavity to perform the thermal solidification forming operation on the sand core. Then, the moving servo cylinder 12 is used to drive the thermal curing box 15 to perform the box retreating operation. When the thermal curing box 15 and the sand shooting box 16 enter and retreat from the box, they elastically slide and reset on the mounting frame 13 through the return spring 17. Then, the mold opening operation is performed. The left mold 2, the right mold 3 and the bottom mold 5 are driven to open the mold by the first mold clamping servo cylinder 6. Then, the formed part is ejected from the mold through the mold ejection seat 4, and the core pulling operation is performed through the core pulling mechanism 7 to complete the forming operation of one workpiece. When different molds need to be replaced, the mold heads are removed from the left mold 2, the right mold 3 and the bottom mold 5, and the upper mold clamping plate 9 is replaced accordingly. At this time, the position of the sand shooting holes 18 can be switched according to the position of the holes in the upper mold clamping plate 9. The corresponding pressure air pipe 26 is controlled by the PLC to intake or exhaust air, so that the plug block 25 cooperates with the adjusting spring 24 to move in the adjusting cavity 23, so that the sand shooting holes 18 at the corresponding positions are opened, while the sand shooting holes 18 at other positions are closed, which is suitable for sand shooting operations of different specifications of molds. During actual operation, data can be input through the PLC controller according to the model or label of the mold to realize the plugging or opening of the corresponding sand shooting holes 18.

[0040] The content not described in detail in this specification belongs to the prior art well-known to those skilled in the art. In the description of the present invention, unless otherwise specified, the meaning of "a plurality of" is two or more; the orientation or positional relationship indicated by terms such as "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "head", "tail", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as a limitation on the present invention. In addition, terms such as "first", "second", "third", etc. are only used for descriptive purposes and cannot be construed as indicating or implying relative importance. In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "connected" and "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0041] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A positive and negative pressure sand shooting mechanism for a core making machine, comprising a frame (1). On the left and right sides of the frame (1), a left mold (2) and a right mold (3) are respectively installed. At the bottom of the frame (1), a mold ejection base (4) is provided. At the top of the mold ejection base (4), a bottom mold (5) is installed. Between the bottom mold (5) and the mold ejection base (4), and between the left mold (2) and the right mold (3) and the frame (1), first mold clamping servo cylinders (6) are fixed. At the same time, a core pulling mechanism (7) is movably installed at the top edge of the mold ejection base (4). It is characterized in that: It further comprises: A second mold clamping servo cylinder (8). The second mold clamping servo cylinder (8) is fixed on the front and rear sides of the top of the frame (1). The output end of the second mold clamping servo cylinder (8) is connected to an upper mold clamping plate (9). The upper mold clamping plate (9) is located inside the frame (1). A pressing box cylinder (10) is fixed on the top of the frame (1). The pressing box cylinder (10) is located between the two second mold clamping servo cylinders (8). A sand shooting air pipe (11) is installed through the pressing box cylinder (10). On the left and right sides at the top of the frame (1), a moving servo cylinder (12) is horizontally fixed. The output end of the moving servo cylinder (12) is connected to a mounting bracket (13). The mounting bracket (13) is movably installed on a guide rail (14). The guide rail (14) is horizontally fixed on the frame (1). At the bottom positions of the left and right groups of mounting brackets (13), a heat curing box (15) and a sand shooting box (16) are respectively fixed. The heat curing box (15) and the sand shooting box (16) are respectively arranged on both sides of the top of the frame (1). A return spring (17) is fixed between the heat curing box (15) and the sand shooting box (16) and the mounting bracket (13). A sand shooting hole (18) is opened at the bottom of the sand shooting box (16). A positive and negative pressure regulating plate (19). The positive and negative pressure regulating plate (19) is embedded in the sand shooting box (16). A positive and negative pressure pipe (20) is horizontally installed through the positive and negative pressure regulating plate (19). At the bottom of the positive and negative pressure pipe (20) and at the corresponding position at the bottom of the positive and negative pressure regulating plate (19), air holes (21) are both opened through. A filter screen (22) is fixed in the air hole (21) at the bottom of the positive and negative pressure regulating plate (19). At the same time, one end of the positive and negative pressure pipe (20) is located outside the sand shooting box (16). An adjusting cavity (23) is opened on the bottom surface of the positive and negative pressure regulating plate (19). The adjusting cavity (23) is located on one side of the positive and negative pressure pipe (20). A plug (25) is connected in the adjusting cavity (23) through an adjusting spring (24). One side of the adjusting cavity (23) is fixedly connected through a pressure air pipe (26). The pressure air pipe (26) is installed through the positive and negative pressure regulating plate (19). One end of the pressure air pipe (26) is located outside the sand shooting box (16). A sand hopper (27) is installed on the top of the sand shooting box (16). The sand hopper (27) is fixed at the top edge of the frame (1). A butterfly valve (28) is installed at the bottom of the sand hopper (27).

2. The positive and negative pressure sand injection mechanism for a core making machine according to claim 1, wherein: The bottom of the pressing cylinder (10) is provided with a bottom plate adapted to the tops of the thermal curing box (15) and the sand shooting box (16). Both the tops of the thermal curing box (15) and the sand shooting box (16) are provided with inlet holes. The inner cavity of the thermal curing box (15) is filled with ceramic heat storage particles, and an electric heating wire is installed in the thermal curing box (15).

3. The positive and negative pressure sand injection mechanism for a core making machine according to claim 1, characterized in that: The cross-section of the mounting frame (13) is in an "L" shape, and the mounting frame (13) elastically slides between the thermal curing box (15) and the sand shooting box (16) through a return spring (17). A hole corresponding to the sand shooting hole (18) is opened at the bottom of the thermal curing box (15).

4. The positive and negative pressure sand injection mechanism for a core making machine according to claim 1, characterized in that: The air holes (21) are equally angularly distributed at the bottom of the positive and negative pressure pipe (20) and the positive and negative pressure regulating plate (19), and the air holes (21) are staggeredly distributed with the sand shooting holes (18).

5. The positive and negative pressure sand injection mechanism for a core-making machine according to claim 1, characterized in that: The filter screen (22) adopts a four-layer mesh structure, and the outer diameter of the filter screen (22) is larger than the inner diameter.

6. The positive and negative pressure sand injection mechanism for a core making machine according to claim 1, characterized in that: The plug block (25) is vertically elastically slidably limited in the adjustment cavity (23) through an adjustment spring (24). The top cross-section of the plug block (25) is in a "T" shape and fits and slides in the adjustment cavity (23). The pressure air pipe (26) in the adjustment cavity (23) is located above the plug block (25). The distribution position of the plug block (25) corresponds to the distribution position of the sand shooting holes (18), and the bottom of the plug block (25) is in concave-convex fit with the sand shooting holes (18).

7. A positive and negative pressure sand injection mechanism for a core making machine according to claim 1, characterized in that: The number of the pressure air pipes (26) is the same as the number of the plug blocks (25). The pressure air pipes (26) are arranged at both ends of the positive and negative pressure regulating plate (19). Which sand shooting hole (18) is opened or closed according to the mold requirements is automatically controlled by a PLC to adjust the internal air pressure of the adjustment cavity (23). One end of each of the positive and negative pressure pipes (20) is installed with an electromagnetic replacement valve and is connected to a vacuum negative pressure gas storage tank and a positive pressure gas storage tank. The connection of the electromagnetic replacement valve on the positive and negative pressure pipes (20) to the vacuum negative pressure gas storage tank and the positive pressure gas storage tank is controlled by a PLC to replace the positive and negative pressures.

8. A positive and negative pressure sand injection mechanism for a core making machine according to claim 1, characterized in that: The sand shooting box (16) is applicable to other conventional core making machines.

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