Equipment and methods for pressing and molding thick brick blanks

Abstract

This invention discloses a pressing and forming device and method for thick brick blanks. The forming device includes an upper mold, a mold sleeve, a lower mold, a main hydraulic cylinder, and a demolding cylinder. The main hydraulic cylinder drives the upper mold, and the demolding cylinder drives the mold sleeve. The main hydraulic cylinder has a first piston rod chamber, and the demolding cylinder has a first piston chamber. The first piston rod chamber and the first piston chamber are connected by a first pipeline, on which a first valve is installed. During pressing, the pressurized oil discharged from the first piston rod chamber enters the first piston chamber through the first pipeline. Implementing this invention can improve uniformity and simplify the control algorithm, thereby improving product quality.

Description

Technical Field

[0001] This invention relates to the field of press technology, and in particular to a molding equipment and method for forming thick brick blanks. Background Technology

[0002] Thick brick blanks generally refer to those with a thickness greater than 30mm, and often exceeding 50mm due to their substantial thickness. Therefore, when using traditional unidirectional pressure for pressing, the side closer to the upper mold tends to have high density, while the side closer to the lower mold (away from the upper mold) has low density, leading to pressing defects such as cracks. Furthermore, even if such pressed blanks do not exhibit defects during the pressing process, they are highly susceptible to defects during subsequent drying and firing. Currently, a common optimization approach is bidirectional pressure, using both the upper and lower molds simultaneously, but this equipment has a complex structure and high cost. Another approach is to use a scheme where the upper mold and mold frame move together to achieve equivalent pressing. However, in this technical solution, the mold frame and upper mold are controlled separately, resulting in low control precision and poor pressing effect. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a molding device for thick brick blanks, which can improve the uniformity of pressing, simplify the structure of the molding device, and reduce the control difficulty of the molding device.

[0004] The technical problem that this invention also aims to solve is to provide a pressing and molding method for thick brick blanks, which has high pressing uniformity and low control difficulty.

[0005] To address the aforementioned problems, this invention discloses a forming device for thick brick blanks, comprising an upper mold, a mold sleeve, a lower mold, a main hydraulic cylinder, and a demolding hydraulic cylinder. The main hydraulic cylinder is used to drive the upper mold to move, and the demolding hydraulic cylinder is used to drive the mold sleeve to move.

[0006] The main cylinder is provided with a first piston rod chamber, and the demolding cylinder is provided with a first piston chamber. The first piston rod chamber and the first piston chamber are connected by a first pipeline, and a first valve is provided on the first pipeline. During pressing, the pressurized oil discharged from the first piston rod chamber enters the first piston chamber through the first pipeline.

[0007] As an improvement to the above technical solution, the ratio of the cross-sectional area of ​​the first piston rod cavity to the cross-sectional area of ​​the first piston cavity is 1:(1.5~3).

[0008] As an improvement to the above technical solution, the ratio of the cross-sectional area of ​​the first piston rod cavity to the cross-sectional area of ​​the first piston cavity is 1:2.

[0009] As an improvement to the above technical solution, the main oil cylinder is provided with a second piston chamber and a first piston rod, and the first piston rod is rigidly connected to the upper mold;

[0010] The demolding cylinder is provided with a second piston rod chamber and a second piston rod. The second piston rod is connected to the mold sleeve. The first piston chamber and the second piston rod chamber are both connected to a reversing valve. The reversing valve is connected to an oil inlet pipe and an oil outlet pipe.

[0011] As an improvement to the above technical solution, the second piston chamber is connected to a second pipeline, which is used to introduce or discharge pressurized oil into the second piston chamber; the first piston rod chamber is connected to a third pipeline, which is used to introduce or discharge pressurized oil into the first piston rod chamber.

[0012] The second pipeline is equipped with a first speed regulating valve, and the third pipeline is equipped with a second speed regulating valve.

[0013] As an improvement to the above technical solution, the second pipeline includes a first main pipeline, a first oil inlet branch and a first oil outlet branch connected in parallel; the first speed regulating valve is located on the first main pipeline, a second valve is located on the first oil inlet branch, and a third valve is located on the first oil outlet branch.

[0014] The third pipeline includes a second main pipeline, a second inlet branch pipeline and a second outlet branch pipeline connected in parallel; the second speed regulating valve is located on the second main pipeline, a fourth valve is located on the second inlet branch pipeline, and a fifth valve is located on the second outlet branch pipeline.

[0015] As an improvement to the above technical solution, a sixth valve is provided on the oil inlet pipeline, and a back pressure valve is provided on the oil outlet pipeline.

[0016] As an improvement to the above technical solution, a first overflow valve is provided on the second main line;

[0017] The first speed control valve and the second speed control valve are proportional valves, and the first valve, the second valve, the third valve, the fourth valve, and the fifth valve are directional valves or cartridge valves.

[0018] As an improvement to the above technical solution, a second overflow valve is provided between the second piston rod chamber and the reversing valve, and the outlet of the second overflow valve is connected to the oil outlet pipeline.

[0019] Accordingly, the present invention also discloses a method for pressing and forming a thick brick blank, comprising:

[0020] The powder is applied into the mold cavity formed by the lower mold and the mold sleeve;

[0021] The upper mold descends at a first preset speed under its own weight or the action of the main hydraulic cylinder until it contacts the powder in the mold cavity;

[0022] The main hydraulic cylinder drives the upper mold to descend at a second preset speed, and the demolding cylinder drives the mold sleeve to descend, so as to apply pressure to the powder in the mold cavity; wherein, the pressurized oil discharged from the first piston rod cavity in the main hydraulic cylinder enters the first piston rod cavity of the demolding cylinder through the first pipeline, so that the upper mold and the mold sleeve descend at a preset speed ratio; wherein, the first preset speed is greater than or equal to the second preset speed;

[0023] The main hydraulic cylinder drives the upper mold to rise, and the demolding hydraulic cylinder drives the mold sleeve to descend until it is flush with the lower mold, and the molded brick blank is taken out.

[0024] Implementing this invention has the following beneficial effects:

[0025] The molding equipment of the present invention includes an upper mold, a mold sleeve, a lower mold, a main hydraulic cylinder, and a demolding cylinder. The main hydraulic cylinder drives the upper mold, and the demolding cylinder drives the mold sleeve. Furthermore, the piston rod chamber of the main hydraulic cylinder and the piston chamber of the demolding cylinder are connected by a pipeline. Based on this structure, the molding equipment can simultaneously control the downward pressing of the upper mold and the downward movement of the mold sleeve during pressing, optimizing pressure transmission and improving uniformity. Simultaneously, since the pressurized oil discharged from the piston rod chamber of the main hydraulic cylinder enters the piston chamber of the demolding cylinder during pressing, the control algorithm is simplified, making the speed ratio of the upper mold and the mold sleeve stable and reliable, thus improving product quality. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the system structure of the forming equipment for thick brick blanks in one embodiment of the present invention [the rapid descent stage of the upper mold, i.e., step (2)];

[0027] Figure 2 This is a schematic diagram of the system structure of a forming device for thick brick blanks in one embodiment of the present invention [the upper mold descends slowly to perform the pressing stage, i.e., step (3)]. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in further detail below.

[0029] This embodiment provides a forming device for thick brick blanks, including an upper mold 1, a mold sleeve 2, a lower mold 3, a main hydraulic cylinder 4 for driving the upper mold, a demolding cylinder 5 for driving the mold sleeve, and an oil tank 6. During pressing, the lower mold 3 remains stationary, the main hydraulic cylinder 4 drives the upper mold 1 to press down, and the demolding cylinder 5 drives the mold sleeve 2 to move down. Based on this technical solution, during the pressing process, the friction force on the powder near the mold sleeve 2 is reduced, promoting the flow of powder near the mold sleeve 2, improving pressure transmission, and enhancing the uniformity of the brick blank, achieving a technical effect similar to bidirectional pressing.

[0030] Furthermore, the main cylinder 4 is provided with a first piston rod chamber 41, and the demolding cylinder 5 is provided with a first piston chamber 51. The first piston rod chamber 41 and the first piston chamber 51 are connected through a first pipeline 7, and a first valve 71 is provided on the first pipeline 7. During pressing, the pressurized oil discharged from the first piston rod chamber 41 enters the first piston chamber 51 through the first pipeline 7. Based on this technical solution, the pressing speed ratio between the upper mold 1 and the mold sleeve 2 can be effectively controlled, further optimizing the pressing effect. Specifically, according to statistics, for refractory bricks (200mm×400mm) with a thickness of 30-35mm (fabric thickness 58-80mm), the yield rate using bidirectional pressing is about 95%; using the molding equipment of this embodiment, the yield rate is about 89-94%, while the yield rate of traditional unidirectional pressing presses is only about 65%.

[0031] Specifically, the speed ratio of the upper mold 1 and the mold sleeve 2 can be controlled by the ratio of the cross-sectional area of ​​the first piston rod cavity 41 to the cross-sectional area of ​​the first piston cavity 51. Specifically, the ratio is 1:(1.5~3), preferably 1:2. Based on this ratio, the yield can be effectively improved, making the yield ≥93%.

[0032] Specifically, in this embodiment, the main cylinder 4 includes a second piston chamber 42, a first piston rod chamber 41, and a first piston rod 43. The first piston rod 43 is rigidly connected to the upper mold 1 to drive the upper mold 1 to move up and down.

[0033] The second piston chamber 42 is connected to a second pipeline 44, which is used to supply or discharge pressurized oil to the second piston chamber 42. The first piston rod chamber 41 is connected to a third pipeline 45, which is used to supply or discharge pressurized oil to the first piston rod chamber 41. Furthermore, a first speed regulating valve 46 is provided on the second pipeline 44, and a second speed regulating valve 47 is provided on the third pipeline 45. The movement speed of the upper die can be controlled by the first speed regulating valve 46 and the second speed regulating valve 47. The first speed regulating valve 46 and the second speed regulating valve 47 can be proportional valves or servo valves, but are not limited to these. A proportional valve is preferred because its control accuracy meets the requirements of the application and its cost is low. It should be noted that because the presses used in fields such as building ceramics and refractory bricks require large tonnages, the area difference between the second piston chamber 42 and the first piston rod chamber 41 is significant. If controlled by a traditional single oil circuit plus a reversing valve, the control difficulty is very high. Therefore, in this embodiment, the second piston chamber 42 and the first piston rod chamber 41 are controlled by separate oil circuits, reducing the control difficulty and improving the control accuracy.

[0034] Specifically, in this embodiment, the second pipeline 44 includes a first main pipeline 441, a first oil inlet branch 442, and a first oil outlet branch 443. The first oil inlet branch 442 and the first oil outlet branch 443 are connected in parallel. The first oil inlet branch 442 is connected to the pressure oil P1, and the first oil outlet branch 443 is connected to the oil tank 6. A first speed regulating valve 46 is installed on the first main pipeline 441 to control the pressure oil flowing out of / into the second piston chamber 42. A second valve 444 is installed on the first oil inlet branch 442, and a third valve 445 is installed on the first oil outlet branch 443. The second valve 444 and the third valve 445 can be directional valves or cartridge valves, but are not limited to these.

[0035] Specifically, in this embodiment, the third pipeline 45 includes a second main pipeline 451, a second oil inlet branch 452, and a second oil outlet branch 453. The second oil inlet branch 452 and the second oil outlet branch 453 are connected in parallel. The second oil inlet branch 452 is connected to the pressure oil P1, and the second oil outlet branch 453 is connected to the oil tank 6. A second speed regulating valve 47 is installed on the second main pipeline 451 to control the flow of pressure oil into / out of the first piston rod chamber 41. A fourth valve 454 is installed on the second oil inlet branch 452, and a fifth valve 455 is installed on the second oil outlet branch 453. The fourth valve 454 and the fifth valve 455 can be reversing valves or cartridge valves, but are not limited to these. Furthermore, a first overflow valve 48 is also provided on the second main pipeline 451 between the first piston rod chamber 41 and the second speed regulating valve 47, which can effectively protect the relatively small area of ​​the first piston rod chamber 41.

[0036] Specifically, in this embodiment, the demolding cylinder 5 includes a first piston chamber 51, a second piston rod chamber 52, and a second piston rod 53. Both the first piston chamber 51 and the second piston rod chamber 52 are connected to a reversing valve 54, which is connected to an oil inlet pipe 55 and an oil outlet pipe 56. The reversing valve 54 effectively controls the flow of pressure oil into / out of the first piston chamber 51 and the second piston rod chamber 52, thereby controlling the movement direction and speed of the mold sleeve 2. Specifically, the reversing valve 54 can be a servo reversing valve or a proportional reversing valve, but is not limited to these. Furthermore, a sixth valve 57 is also provided on the oil inlet pipe 55, which can be a reversing valve or a cartridge valve, but is not limited to these.

[0037] Furthermore, a back pressure valve 58 is installed on the oil outlet line 56, which provides back pressure to the second piston rod chamber 52 to ensure that the mold sleeve 2 is suspended in a reasonable position. A second relief valve 59 is installed on the line between the second piston rod chamber 52 and the reversing valve 54, and the outlet of the second relief valve 59 is connected to the oil outlet line 56.

[0038] Furthermore, the equivalent bidirectional press in this embodiment is also equipped with a displacement sensor 8, which is located next to the upper mold 1 and the mold sleeve 2. The actual speed of the upper mold 1 and the mold sleeve 2 can be calculated in real time through the displacement sensor 8.

[0039] Accordingly, the present invention also discloses a pressing and molding method based on the above-mentioned pressing and molding equipment, which specifically includes:

[0040] (1) The powder material is applied into the mold cavity formed by the lower mold and the mold sleeve;

[0041] Specifically, the powder is applied into the mold cavity formed by the mold sleeve 2 and the lower mold 3. In this step, the pressure provided by the back pressure valve 58 causes the mold sleeve 2 to suspend in a specific position and remain stationary (i.e., maintain the depth of the mold cavity).

[0042] (2) The upper mold descends at a first preset speed under its own weight or the action of the main hydraulic cylinder until it contacts the powder in the mold cavity;

[0043] Specifically, in one embodiment, the upper mold 1 descends rapidly under its own weight. In this step, the second valve 444 is closed, meaning no pressurized oil flows into the second piston chamber 42. The second speed regulating valve 47 and the fifth valve 455 are opened, allowing the pressurized oil in the first piston rod chamber 41 to be discharged into the oil tank 6 via the second main channel 451 and the second oil outlet branch channel 453. In this step, the descent speed of the upper mold 1 can be controlled by controlling the second speed regulating valve 47. When the upper mold 1 contacts the powder in the mold cavity, this step ends, and the next step begins.

[0044] (3) The main hydraulic cylinder drives the upper mold to descend at the second preset speed, and the demolding hydraulic cylinder drives the mold sleeve to descend, so as to apply pressure to the powder in the mold cavity;

[0045] Specifically, when the upper mold 1 contacts the powder, the increased pressure requirement causes the second valve 444 to open, allowing pressurized oil to enter the second piston chamber 42 via the first inlet branch 442, the first speed regulating valve 46, and the first main line 441, providing downward pressure. At this time, the sixth valve 57 and the second speed regulating valve 47 are closed, and the first valve 71 is opened. Pressurized oil discharged from the first piston rod chamber 41 enters the first piston chamber 51 via the first pipeline 7, thereby pushing the mold sleeve 2 downward. For the demolding cylinder 5, the pressurized oil in the second piston rod chamber 52 enters the outlet pipeline 56 via the reversing valve 54, and is then discharged into the oil tank 6.

[0046] Specifically, the second preset speed is less than or equal to the first preset speed. Using a slower speed in this step can improve the uniformity of pressing.

[0047] (4) The main hydraulic cylinder drives the upper mold to rise, and the demolding hydraulic cylinder drives the mold sleeve to descend until it is flush with the lower mold, and the molded brick blank is taken out.

[0048] Specifically, when the second piston chamber 42 reaches the preset pressure or the upper mold 1 is pressed down to the preset displacement, the pressing is completed. At this time, the upper mold 1 is controlled to rise, and the mold sleeve 2 continues to descend. After the mold sleeve 2 is lowered to be flush with the lower mold 3, the formed brick blank is pushed out. In this step, the mold sleeve 2 continues to descend. At this time, the first valve 71 is disconnected, and pressurized oil is introduced into the first piston chamber 51 through the oil inlet pipe 55 and the reversing valve 54. At the same time, the pressurized oil in the second piston rod chamber 52 enters the oil outlet pipe 56 through the reversing valve 54 and is then discharged into the oil tank 6. In this step, the upper mold 1 begins to rise. Specifically, the fourth valve 454 is opened, and pressurized oil is introduced into the first piston rod chamber 41 through the second oil inlet branch 452, the second speed regulating valve 47, and the second main line 451. At this time, the fifth valve 455 is closed. At the same time, the second valve 444 is closed and the third valve 445 is opened, so that the pressure oil in the second piston chamber 42 flows out to the oil tank 6 through the first main line 441, the first speed regulating valve 46, and the first oil outlet branch line 443.

[0049] Preferably, in one embodiment, the molding method further includes:

[0050] (5) The upper mold rises to the pre-pressing position under the action of the main oil cylinder, and the mold sleeve rises to the pre-pressing position under the drive of the demolding oil cylinder.

[0051] Specifically, in this step, the upper mold 1 continues to rise, while the mold sleeve 2 is controlled to rise. Specifically, the reversing valve 54 is controlled to introduce pressurized oil into the second piston rod chamber 52, causing the mold sleeve 2 to move upward. At the same time, the back pressure valve 58 is opened, allowing the pressurized oil in the first piston chamber 51 to be discharged into the oil tank 6. After a certain period of time, the upper mold and mold sleeve are returned to their positions before pressing.

[0052] The above description is a preferred embodiment of the invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principle of the invention, and these improvements and modifications are also considered to be within the scope of protection of the invention.

Claims

1. A forming device for thick brick blanks, characterized in that, It includes an upper mold, a mold sleeve, a lower mold, a main hydraulic cylinder, and a demolding cylinder. The main hydraulic cylinder is used to drive the upper mold to move, and the demolding cylinder is used to drive the mold sleeve to move. The main cylinder is provided with a first piston rod chamber, and the demolding cylinder is provided with a first piston chamber. The first piston rod chamber and the first piston chamber are connected by a first pipeline, and a first valve is provided on the first pipeline. During pressing, the pressure oil discharged from the first piston rod chamber enters the first piston chamber through the first pipeline. The main cylinder is provided with a second piston chamber and a first piston rod, the first piston rod being rigidly connected to the upper mold; the second piston chamber is connected to a second pipeline, the second pipeline being used to introduce or discharge pressurized oil into the second piston chamber; the second pipeline is provided with a first speed regulating valve; The second pipeline includes a first main pipeline, a first inlet branch pipeline and a first outlet branch pipeline connected in parallel; the first speed regulating valve is located on the first main pipeline, a second valve is located on the first inlet branch pipeline, and a third valve is located on the first outlet branch pipeline. The demolding cylinder is provided with a second piston rod chamber and a second piston rod, the second piston rod being connected to the mold sleeve; the first piston rod chamber is connected to a third pipeline, the third pipeline being used to supply or discharge pressurized oil to the first piston rod chamber; a second speed regulating valve is provided on the third pipeline; The third pipeline includes a second main pipeline, a second oil inlet branch pipeline and a second oil outlet branch pipeline connected in parallel; the second speed regulating valve is located on the second main pipeline, a fourth valve is located on the second oil inlet branch pipeline, and a fifth valve is located on the second oil outlet branch pipeline. Both the first piston chamber and the second piston rod chamber are connected to a reversing valve, which is connected to an oil inlet pipe and an oil outlet pipe.

2. The forming equipment for thick brick blanks as described in claim 1, characterized in that, The ratio of the cross-sectional area of ​​the first piston rod cavity to the cross-sectional area of ​​the first piston cavity is 1:(1.5~3).

3. The forming equipment for thick brick blanks as described in claim 2, characterized in that, The ratio of the cross-sectional area of ​​the first piston rod cavity to the cross-sectional area of ​​the first piston cavity is 1:

2.

4. The forming equipment for thick brick blanks as described in claim 1, characterized in that, The oil inlet pipe is equipped with a sixth valve, and the oil outlet pipe is equipped with a back pressure valve.

5. The forming equipment for thick brick blanks as described in claim 1, characterized in that, The second main line is equipped with a first overflow valve; The first speed control valve and the second speed control valve are proportional valves, and the first valve, the second valve, the third valve, the fourth valve, and the fifth valve are directional valves or cartridge valves.

6. The forming equipment for large-thickness brick blanks as described in claim 4, characterized in that, A second overflow valve is provided between the second piston rod chamber and the reversing valve, and the outlet of the second overflow valve is connected to the oil outlet pipeline.

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